Title of Invention	PERMANENT MAGNET TYPE ROTARY ELECTRIC MACHINE AND DRIVE UNIT FOR SAME
Abstract	A permanent magnet type rotary electric machine wherein a rotor yoke of a generally cylindrical shape adapted to rotate along an outer periphery of a stator is formed with a plurality of magnet inserting holes in a circumferential direction thereof alternately with interpoles, and permanent magnets are inserted into said magnet inserting holes, respectively, characterized in that: said magnetic inserting holes each comprises a main opening for insertion therein of each of said permanent magnets and slits extending with a predetermined width (W) toward a central portion from both end portions in the circumferential direction of said main opening, and a residual thickness (H) of the rotor yoke at the tip of each said slit and said slit width (W) satisfy the relationship of 0.3 < residual thickness (H) /slit width (W) < 0.7, and Wherein said permanent magnet type rotary electric machine comprises a control unit which feeds an exciting current from a battery to each stator winding at a rotational speed lower than a predetermined rotational speed, and is driven by the internal combustion engine at a rotational speed not lower than a predetermined rotational speed.

Title of Invention

PERMANENT MAGNET TYPE ROTARY ELECTRIC MACHINE AND DRIVE UNIT FOR SAME

Abstract

A permanent magnet type rotary electric machine wherein a rotor yoke of a generally cylindrical shape adapted to rotate along an outer periphery of a stator is formed with a plurality of magnet inserting holes in a circumferential direction thereof alternately with interpoles, and permanent magnets are inserted into said magnet inserting holes, respectively, characterized in that: said magnetic inserting holes each comprises a main opening for insertion therein of each of said permanent magnets and slits extending with a predetermined width (W) toward a central portion from both end portions in the circumferential direction of said main opening, and a residual thickness (H) of the rotor yoke at the tip of each said slit and said slit width (W) satisfy the relationship of 0.3 < residual thickness (H) /slit width (W) < 0.7, and Wherein said permanent magnet type rotary electric machine comprises a control unit which feeds an exciting current from a battery to each stator winding at a rotational speed lower than a predetermined rotational speed, and is driven by the internal combustion engine at a rotational speed not lower than a predetermined rotational speed.

Full Text	ORIGINAL 746/MUM/2001 205062 FORM 2 THE PATENTS ACT 1970 [39 OF 1970] & THE PATENTS RULES, 2003 COMPLETE SPECIFICATION [See Section 10; rule 13] "PERMANENT MAGNET TYPE ROTARY ELECTRIC MACHINE AND DRIVE UNIT FOR SAME" HONDA GIKEN KOGYO KABUSHIKl KAISHA, a corporation of Japan, having a place of business at 1-1, Minamiaoyama 2-chome, Minato-ku, Tokyo, Japan, The following specification particularly describes the invention and the manner in which it is to be performed: GRANTED 3 MAR 2006 3-3-2006 The present invention relates to permanent magnet type rotaiy electric machine and drive unit for same. The present invention relate to a permanent magnet type rotary electric machine wherein a rotor yoke having a plurality of permanent magnets arranged in a circumferential direction thereof is adapted to rotate along an outer periphery of a stator, as well as a drive unit for the same. Particularly, the invention is concerned with a permanent magnet type rotary electric machine wherein the rotor yoke have interpoles alternately with permanent magnets, as well as a drive unit for the same. [0002] [Prior Art] Heretofore, a starter motor and a generator both for an internal combustion engine have been provided separately from each other, but a starter/generator having the respective functions in an integrated state is disclosed, for example, in Japanese Patent Laid-open No. Hei 10-148142. [0003] On the other hand, as a starter motor for an internal combustion engine there is known an outer rotation, permanent magnet type rotary electric machine wherein a cylindrical rotor yoke rotates along an outer periphery of a stator. Further, for example in Japanese Patent Laid-open No. Hei 8-275476 there is disclosed such a permanent magnet type rotary electric machine wherein interpoles are formed so as to be each positioned between adjacent permanent magnets to mitigate a strain of a magnetic flux distribution between a rotor and a stator and thereby prevent the occurrence of torque oscillation. [0004] [Problems to be Solved by the Invention] In the conventional permanent magnet type rotary electric machine described above, between permanent magnets adjacent to each other with an interpole therebetween there occurs a leaking magnetic flux with the interpole as a magnetic path and hence an effective magnetic flux diminishes. Therefore, if it is intended to obtain a larger amount of driving torque, it is necessary to increase the size of each permanent magnet used or increase an exciting current for a stator winding. But an increase in size and weight of the motor or an increase in power consumption results. [0005] Further, where it is intended to let one motor function as a starter motor at the time of starting an internal combustion engine and also function as a generator during travel of the vehicle concerned, an increase in size of permanent magnets will afford a large driving force if the motor is allowed to function as a starter motor, but larger electric power than necessary will be generated if the motor is allowed to function as a generator, thus resulting in an increase of torque (driven torque) which the internal combustion engine, indicated at E, requires for driving a starter/generator. [0006] In the conventional permanent magnet type rotary electric machine described above, the ratio [Wmg:Wsp] of the width, Wmg, of each permanent magnet to the width, Wsp, of each interpole both in the rotational direction exerts a great influence on the torque in a low rotation region particularly when the electric machine is allowed to function as an electric motor. In the foregoing prior art, however, no consideration is given to an appropriate relation of the ratio [Wmg:Wsp] to an increase of friction when the permanent magnet type rotary electric machine is allowed to function as a generator. [0007] Further, in the permanent magnet type rotary electric machine of the structure described above, since the interposes function as part of the permanent magnets, it is desirable that the supply of an electric current to the rotary electric machine be advanced by an angle corresponding to the width Wsp of each interpole. In the foregoing prior art, however, no consideration is given to an appropriate relation between the interloped width Wsp and the advance angle. [0008] It is a first object of the present invention to solve the above-mentioned technical problems of the prior art and provide a permanent magnet type rotary electric machine as a starter/generator capable of affording a large driving torque when it is allowed to function as a starter motor and diminishing a driven torque when allowed to function as a generator. [0009] It is a second object of the present invention to solve the above-mentioned problems of the prior art and provide a permanent magnet type rotary electric machine having an optimum ration [Wmg:Wsp] of the permanent magnet width Wmg to the Interpol width Wsp. [0010] It is a third object of the present invention to solve the above-mentioned problems of the prior art and provide a drive unit for a permanent magnet type rotary electric machine having an optimum relation between the Interpol width Wsp and the advance angle in the supply of an electric current. [0011] [Means for Solving the Problems] According to the present invention, for achieving the first object, there is provided a permanent magnet type rotary electric machine wherein a rotor yoke of a generally cylindrical shape adapted to rotate along an outer periphery of a stator is formed with a plurality of magnet inserting holes in a circumferential direction thereof alternately with interposes, and permanent magnets are inserted into the magnet inserting holes, respectively, characterized in that the magnet inserting holes each comprise a main opening for insertion therein of each of the permanent magnets and slits (first clearances) extending with a predetermined width (w) toward a central portion from both end portions in the circumferential direction of the main opening, and a residual thickness (H) of the rotor yoke at the tip of each of the slits and the slit width (W) satisfy the relationship of 0.3 Widening the slit width (W) is equivalent to thinning the residual thickness (H), which is disadvantageous from the standpoint of decreasing the driven torque. Conversely, increasing the residual thickness (H) is disadvantageous from the standpoint of increasing the driving torque. Thus, widening the slit width (W) to increase the driving torque and increasing the residual thickness H of the rotor yoke to decrease The driven torqueses are antinomy events. If priority is given to increasing the driving torque, the ratio (H/W) of the two must be set low, while if priority is given to decreasing the driven torque, the ratio (H/W) must be set high. However, if 0.3 [0013] For achieving the second and third objects the present invention is characterized by adopting the following means. [0014] (1) In a permanent magnet type rotary electric machine wherein a rotor yoke of a generally cylindrical shape adapted to rotate along an outer periphery of a stator is formed with a plurality of magnet inserting holes in a circumferential direction thereof alternately with interposes, and permanent magnets are inserted into the magnet inserting holes, respectively, a feature resides in that the ratio [Wmg:Wsp] of the width, Wmg, of each of the permanent magnets to the width, Wsp, of each of the interposes both in a rotational direction is approximately [5:1]. [0015] (2) In a drive unit for a permanent magnet type rotary electric machine wherein a rotor yoke of a generally cylindrical shape adapted to rotate along an outer periphery of a stator is formed with a plurality of magnet inserting holes in a circumferential direction thereof alternately with interposes, and permanent magnets are inserted into the magnet inserting holes, respectively, a feature resides in that the phase of an alternating current to be fed to each phase terminal of the permanent magnet type rotary electric machine is advanced by an angle corresponding to 1 to 1.5 times the width, Wsp, of each Interpol in a rotational direction. [0016] According to the above features, not only the improvement of torque is attained particularly in a low rotation region when the permanent magnet type rotary electric machine is allowed to function as an electric motor, but also the friction is diminished when the rotary electric machine is allowed to function as a generator. Thus, it is possible to realize a well-balanced rotary electric machine. [0017] [Mode for Carrying Out the Invention] The present invention will be described below in Detail with reference to the drawings. The present invention relates to a permanent magnet type rotary electric machine wherein a rotor yoke of a generally cylindrical shape adapted to rotate along an outer periphery of a stator is formed with a plurality of magnet inserting holes in a circumferential direction thereof alternately with interposes, and permanent magnets are inserted into said magnet inserting holes, respectively, characterized in that: said magnetic inserting holes each comprises a main opening for insertion therein of each of said permanent magnets and slits extending with a predetermined width (W) toward a central portion from both end portions in the circumferential direction of said main opening, and a residual thickness (H) of the rotor yoke at the tip of each said slit and said slit width (W) satisfy the relationship of 0.3 Wherein said permanent magnet type rotary electric machine comprises a control unit which feeds an exciting current from a battery to each stator winding at a rotational speed lower than a predetermined rotational speed, and is driven by the internal combustion engine at a rotational speed not lower than a predetermined rotational speed. [BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS] [FIG. 1] Fig 1 is an entire side view of a scooter type two -wheeled motor vehicle in which a permanent magnet type rotary electric machine embodying the present invention is applied to a starter/generator. [FIG. 2] Fig. 2 is a sectional view of a swing unit shown in Fig. 1, taken a crank shaft. [FIG. 3] Fig. 3 is a partially cut-away plan view taken along a plane perpendicular to a rotary shaft (crank shaft) of the starter/ generator (the permanent magnetic type rotary electric machine). [FIG. 4] Fig. 4 is a sectional side view of Fig. 3. [Fig. 5] Fig. 5 is a plan view of a rotor yoke. [Fig. 6] Fig. 6 is a side view of the rotor yoke. [Fig. 7] Fig. 7 is a partial enlarged view of the rotor yoke [Fig. 8] Fig. 8 is a block diagram of a control system used in the starter/generator. [Fig. 9] Fig. 9 is a diagram for explaining the function (as a starter motor) of slits and clearances formed in the rotor yoke. [Fig. 10] Fig. 10 is a diagram for explaining the function (as a generator) of the slits and clearances formed in the rotor yoke. [Fig. 11] Fig. 11 is a diagram showing a plane shape of a rotor yoke according to the second embodiment of the present invention. [Fig. 12] Fig. 12 is a partial enlarged diagram showing a state in which a permanent magnet is inserted into an Opening shown in Fig. 11. [Fig. 13] Fig. 13 is a diagram showing a plane shape of a rotor yoke according to the third embodiment of the present invention. [Fig. 14] Fig. 14 is a partial enlarged diagram showing a state in which a permanent magnet is inserted into an opening shown in Fig. 13. [Fig. 15] Fig. 15 is a diagram showing a plane shape of a rotor yoke according to the fourth embodiment of the present invention. [Fig. 16] Fig. 16 is a partial enlarged diagram showing a state in which a permanent magnet is inserted into an opening shown in Fig. 15. [Fig. 17] Fig. 17 is a diagram showing a plane shape of a rotor yoke according to the fifth embodiment of the present invention. [Fig. 18] Fig. 18 is a partial enlarged diagram showing a state in which a permanent magnet is inserted into an Opening shown in Fig. 17. [Fig. 19] Fig. 19 is a diagram showing a plane shape of a rotor yoke according to the sixth embodiment of the present invention. [Fig. 20] Fig. 20 is a partial enlarged diagram showing a state in which a permanent magnet is inserted into an opening shown in Fig. 19. [Fig. 21] Fig. 21 is a partial enlarged diagram of Fig. 9. [Fig. 22] Fig. 22 is a partial enlarged diagram of Fig. 10. [Fig. 23] Fig. 23 is a diagram showing a relation between an advance angle of a power supply timing and torque in 120° power supply control with rotor revolutions as a parameter ([Wmg:Wsp] is about [5:1]). [Fig. 24] Fig. 24 is a diagram showing a relation between an advance angle of a power supply timing and torque in 120° power supply control with rotor revolutions as a parameter ([Wmg:Wsp] is about [4:1]). [Fig. 25] Fig. 25 a diagram showing a relation between an advance angle of a power supply timing and torque in 12 0° power supply control with rotor revolutions as a parameter ([Wmg:Wsp] is about [2.8:1]). [Fig. 26] Fig. 26 is a diagram showing a relation between an advance angle of a power supply timing and torque in 180° power supply control with rotor revolutions as a parameter ([Wmg:Wsp] is about [5:1]). [Fig. 27] Fig. 27 is a diagram showing a relation between an advance angle of a power supply timing and torque in 180° power supply control with rotor revolutions as a parameter ([Wmg:Wsp] is about [4:1]). [Fig. 28] Fig. 28 is a diagram showing a relation between an advance angle of a power supply timing and torque in 180° power supply control with rotor revolutions as a parameter ([Wmg:Wsp] is about [2.8:1]). [Fig. 29] Fig. 29 is a diagram showing a relation between the ratio (H/W) of a residual thickness H of a rotor yoke at the tip of a slit to the slit width W and a driving torque. [Fig. 30] Fig. 30 is a diagram showing a relation between said ratio (H/W) and a driven torque. Fig. 1 is a .............................................................................. entire side view of a scooter type two-wheeled motor vehicle in which a permanent magnet type rotary electric machine according to the present invention is applied to a starter/generator. [0018] A front body portion 3a and a rear body portion 3b are connected together through a low floor portion 4, and a body frame which constitutes a skeleton of the vehicle body is substantially composed of a down-tube 6 and a main pipe 7. A fuel tank and a receptacle box (neither shown) are supported by the main pipe 7 and a seat 8 is disposed there above. [0019] In the front body portion 3a, a handle 11 is provided at an upper position in a pivotally supported state by a steering head 5, while a front fork 12 extends downward, with a front wheel FW being supported at a lower end of the front fork through an axle. An upper portion of the handle 11 is covered with a handle cover 13 which also serves as an instrument board. A bracket 15 is projecting provided on a lower end of a rise portion of the main pipe 7 and a hanger bracket 18 of a swing unit 2 is connected to the bracket 15 swing ably through a link member 16. [0020] On a front portion of the swing unit 2 is mounted a single-cylinder two-stroke internal combustion engine E, and a belt type continuously variable transmission 26 is constituted backward from the internal combustion engine E. A reduction mechanism 27 is connected to a rear portion of the continuously variable transmission 26 through a centrifugal clutch and a rear wheel RW is supported by the reduction mechanism 27 through an axle. A rear cushion 22 is interposed between an upper end of the reduction mechanism 27 and an upper bent portion of the main pipe 7. On the front side of the swing unit 2 are disposed a carburetor 24 connected to an intake pipe 23 extending from the internal combustion engine E and an air cleaner 25 connected to the carburetor 24. [0021] Fig. 2 is a sectional view of the swing unit 2 taken along a crank shaft 201, in which the same reference numerals as in the above description represent the same or equivalent portions. [0022] The swing unit 2 is covered with a crank case 202 which is constituted by a combination of left and right Crank cases 202L, 202R. The crank shaft 201 is supported rotatably by bearings 208 and 209 which are fixed to the crank case 202R. To the crank shaft 201 is connected a connecting rod (not shown) through a crank pin 213. [0023] The left crank case 202L also serves as a belt type continuously variable transmission case, and a belt driving pulley 210 is mounted rotatably on the crank shaft 201 extending up to the left crank case 202L. The belt driving pulley 210 comprises a fixed pulley half 210L and a movable pulley half 210R. The fixed pulley half 210L is fixed to a left-end portion of the crank shaft 201 through a boss 211, while on the right-hand side of the fixed pulley half 210L the movable pulley half 210R is spilled to the crank shaft 201 so as to be movable toward and away from the fixed pulley half 210L, with V belt 212 being entrained between both pulley halves 210L and 210R. [0024] On the right-hand side of the movable pulley half 210R a cam plate 215 is fixed to the crank shaft 201 and a slide piece 215a provided at an outer peripheral end of the cam plate 215 is slidably engaged with a cam plate sliding boss portion 210Ra which is formed axially at an Outer periphery ends of the movable pulley half 210R. The cam plate 215 located on the right-hand side of the movable pulley half 210R has a tapered surface inclined toward the movable pulley half 210R at a portion thereof close to its outer periphery, and a dry weight ball 216 is accommodated within a space formed between the said tapered surface and the movable pulley half 210R. [0025] As the rotational speed of the crank shaft 201 increases, the dry weight ball 216, which is located between the movable pulley half 210R and the cam plate 215 and is adapted to rotate accordingly, moves in a centrifugal direction under the action of a centrifugal force, so that the movable pulley half 210R is pushed by the dry weight ball 216, moves leftwards and approaches the fixed pulley half 210L. As a result, the V belt 212 sandwiched in between both pulley halves 210L and 210R moves in the centrifugal direction and its winding diameter becomes larger. [0026] In a rear portion of the vehicle is installed a driven pulley (not shown) mating with the belt driving pulley 210 and the V belt 212 is entrained on the driven pulley. With this belt transfer mechanism, the power from The internal combustion engine E is adjusted automatically and is transmitted to a centrifugal clutch to drive the rear wheel RW through the reduction mechanism 27, etc. [0027] Within the right crank case 202R is disposed a starter/generator 1 as a combination of a starter motor and an AC generator. In the starter/generator 1, an outer rotor 60 is fixed with screw 253 onto a tapered end portion of the crank shaft 201. An inner stator 50, which is disposed inside the outer rotor 60, is threadedly secured to the crank case 202 with a bolt 279 and is supported thereby. As to the construction of the starter/generator, it will be described later in detail with reference to Figs. 3 to 7. [0028] A fan 280 has a central conical portion 280a, a skirt portion of which is fixed to the outer rotor 60 with a bolt 246. The fan 280 is covered with a fan cover 281 through a radiator 282. [0029] A sprocket 231 is fixed onto the crank shaft 201 at a position between the starter/generator 1 and the bearing 209 and a chain is entrained on the sprocket 231 to drive a cam shaft (not shown) from the crank shaft 201. The sprocket 231 is integral with a gear 232 which is for the transfer of power to a lubricant oil circulating pump. [0030] Figs. 3 and 4 are a partially cut-away plan view and a sectional side view thereof taken along a plane perpendicular to the rotational shaft (crank shaft 201) of the starter/generator 1 (a permanent magnet type rotary electric machine), and Figs. 5 and 6 are a plan view of a rotor yoke and a partial enlarged view thereof, respectively. In these figures, the same reference numerals as in the previous description represent the same or equivalent portions. [0031] As shown in Figs. 3 and 4, the starter/generator 1 of this embodiment is made up of the stator 50 and the outer rotor 60 adapted to rotate along the outer periphery of the stator 50. The outer rotor 60 is made up of a rotor yoke 61 constituted by stacking ring-like silicon steel sheets (thin sheets) in a generally cylindrical shape, as shown in Figs. 4 and 5, N-pole permanent magnets 62N and S-pole permanent magnets 62S inserted alternately into plural openings 611 formed in the circumferential direction of the rotor yoke 61, as shown in Figs. 3 and 7, and a cup-like rotor case 63 which connects the rotor yoke 61 to the crank shaft 201, as shown in Figs. 3 and 4. [0032] The rotor case 63 is formed with a pawl portion 63a along its circumferential end portion. By bending the pawl portion 63a inwards the rotor yoke 61 of the stacked structure described above is held grippingly and the permanent magnets 62 (62N, 62S) inserted respectively into the openings 611 of the rotor yoke are held at predetermined positions in the rotor yoke 61. [0033] The stator 50 is constituted by stacking silicon steel sheets (thin sheets) and includes a stator core 51 and stator salient poles 52, as shown in Fig. 3. A stator winding 53 is wound round each stator salient pole 52 in a single pole concentrated manner and a main surface of the stator 50 is covered with a protective cover 71. [0034] In the rotor yoke 61, as shown in Figs. 5 and 6, twelve openings 611, into which the permanent magnets 62 are inserted axially, are formed circumferentially at intervals of 30°. In both circumferential ends of each opening 611 are formed slits (second clearances) 614 with a predetermined width toward a central portion. The portion between adjacent openings 611 functions as an interpole 613. Into each of the openings 611 is inserted a permanent magnet 62 of a generally drum-like section, as shown in Fig. 7. The ratio [Wmg:Wsp] of the width of each opening 611, i.e., the width, Wmg, of each permanent magnet 62 to the width, Wsp, of each interpole 613 is set at approximately [5:1], as shown in Fig. 6. [0035] Into each of the openings 611 is inserted a permanent magnet 62 of a generally drum-like section, as shown in Fig. 7. In this embodiment, the shape of each opening 611 and the sectional shape of each permanent magnet 62 are not the same, but when the permanent magnet 62 is inserted into the opening 611, slits (first clearances) 612 are formed on both sides in the circumferential direction of each permanent magnet 62 and the slits 614 are left on the stator side at both ends of each permanent magnet 62. [0036] Fig. 8 is a block diagram of a control system used in the starter/generator 1, in which the same reference numerals as in the above description represent the same or equivalent portions. [0037] A control unit 40 includes a DC-DC converter 102 which converts an output voltage VBATT of a battery 42 into a logic voltage VDD and supplies the logic voltage VDD to a CPU 101, an ignition controller 103 which controls the supply of electric current to an IG coil 41 and causes a spark plug 43 to spark at a predetermined timing, and a three-phase driver 104 which converts the battery voltage VBATT into three-phase AC power and supplies it to the stator windings 53. [0038] A throttle sensor 45 detects a throttle opening 6 th and notifies the CPU 101 of the result. Likewise, a rotor sensor 46 detects a rotational position of the outer rotor 60 and notifies the CPU 101 of the result. Further, a regulator 44 controls an induced electromotive force to be generated in the stator windings 53 into a predetermined battery voltage VBATT in accordance with rotation of the outer rotor 60. [0039] In such a configuration, when starting an engine, the CPU 101 determines an excitation timing for the stator windings 53 on the basis of the rotational position of the outer rotor 60 detected by the rotor sensor 46, controls a switching timing of each power FET in the three-phase driver 104 and supplies AC power to each phase of the stator winding 53. [0040] Each of power FETs (Trl~Tr6) in the three-phase driver 104 is PwM-controlled by the CPU 101 and a duty ratio, or a driving torque, thereof is controlled in accordance with the number of revolutions of the outer rotor 60. [0041] On the other hand, upon start-up of the internal combustion engine E, the supply of electric power from the three-phase driver 104 to the stator windings 53 is stopped, and then starter/generator 1 is driven by the internal combustion engine E. At this time, an electromotive force is generated in the stator windings 53 in accordance with the rotational speed of the crank shaft 201. This electromotive force is controlled to the battery voltage VBATT by the regulator 44 and is fed to each electric load, while surplus electric power is charged to the battery 42. [0042] Figs. 23, 24 and 25 each illustrate a relation between an advance degree (°) of a power supply timing and torque (N/m) with rotor revolutions (rpm) as a parameter in 120° power supply control. In Figs. 23, 24, and 25, the ratios [Wmg:Wsp] of the width, Wmg, of each permanent magnet 62 to the width, Wsp, of each interpole 613 are approximately [5:1], [4:1], and [2.8:1], respectively. [0043] In the example shown in Fig. 23 in which the ratio [Wmg:Wsp] is approximately [5:1], high torques are generated at advance degrees in the range of 5' to 7 * or 8° regardless of whether the number of revolutions of the rotor is large or small. On the other hand, in the examples shown in Figs. 24 and 25 in which the ratios [Wmg:Wsp] are approximately [4:1] and [2.8:1], respectively, the drop of torque becomes conspicuous as the advance degree is increased when the number of revolutions of the rotor is small (40 rpm). [0044] Figs. 26, 27 and 28 each illustrate a relation between an advance degree (*) of a power supply control and torque (N/m) with rotor revolutions (rpm) as a parameter. In Figs. 26, 27, and 28, the ratios [Wmg:Wsp] of the width, Wmg, of each permanent magnet 62 to the width, Wsp, of each interpole 613 are approximately [5:1], [4:1], and [2.8:1], respectively. [0045] In the example shown in Fig. 26 in which the ratio [wmg:wsp] is approximately [5:1], high torques are generated at advance degrees in the range of 5' to 7' or 8° particularly when the number of revolutions of the rotor is small. On the other hand, in the examples shown in Figs. 27 and 28 in which the ratios [wmg:wsp] are approximately [4:1] and [2.8:1], respectively, torques generated at small rotor revolutions are inferior in comparison with the example shown in Fig. 26 in which the ratio [Wmg:Wsp] is approximately [5:1]. [0046] Thus, according to the results of experiments made by the inventor it is seen that in both 120° and 180" power supply controls high torques are obtained particularly in a low rotation region of the rotor when the ratio [wmg:Wsp] of the width, wmg, of each permanent magnet 62 to the width, wsp, of each interpole 613 is approximately [5:1]. It is also seen that a high torque is obtained if the advance degree is set at a value in the range of 5° to 7' or 8°, i.e., at a value 1 to 1.5 times the angle (5° in this embodiment) of each interpole 613. [0047] No ith reference to Figs. 9 and 10, a description will be given below of the operation of the slits 614 formed in the rotor yoke 61 and the clearances 612 formed between the rotor yoke 61 and the permanent magnets 62. [0048] Fig. 9 illustrates a magnetic flux density distribution obtained when the starter/generator 1 is allowed to function as a starter motor, while Fig. 10 illustrates a magnetic flux density distribution obtained when the starter/generator 1 is allowed to function as a generator. [0049] When the starter/generator 1 is allowed to function as a starter motor, if an exciting current is fed from the battery 42 to each stator winding 53 through the control unit 40, as shown in Fig. 9, magnetic lines of force generated in a radial direction from each N-magnetized stator salient pole 52N pass through the back from the stator-side surface of each S-pole permanent magnet 62S and many of them passes through a core portion 615 of the rotor yoke 61 and an interpole 613, then further passes through an adjacent S-magnetized stator salient pole 52S and the stator core 51, and returns to the N-magnetized stator salient pole 52N. [0050] In this case, since in this embodiment clearances 612 are formed on both sides of in the circumferential direction of each permanent magnet 62 and magnetic flux leaking from side portions of each permanent magnet 62 to the interpole 613 side is diminished thereby, most of the magnetic lines of force pass from each permanent magnet 62 to the core portion 615 of the rotor yoke 61 and reach the stator 50 side via the interpoles 613. As a result, a vertical component of the magnetic flux passing through the air gap between the outer rotor 60 and the stator 50 increases, so that it becomes possible to increase the driving torque in comparison with the case where the clearances 612 are not formed. [0051] Further, since in this embodiment slits 614 for limiting a magnetic path in the circumferential direction are also formed on the stator side at both end portions of each permanent magnet 62, leaking magnetic flux which passes the inside of the rotor yoke 61 also diminishes. [0052] More specifically, as in Fig. 21 which illustrates the interior of a broken-line circle in Fig. 9 on a larger scale, one (614A) of the slits (second clearances) 614 acts to conduct a magnetic flux Bl efficiently from an interpole 613 of the rotor yoke 61 to the stator salient pole 52S. The other (614B) of the clearances 614 acts to conduct a magnetic flux B2 to the stator salient pole 52S efficiently, the magnetic flux B2 passing through the inner circumferential portion 616 of the rotor yoke 61 from the permanent magnet 62N. As a result, a vertical component of magnetic flux passing through the air gap between the outer rotor 60 and the stator 50 further increases and it becomes possible to further increase the driving torque as the starter motor. [0053] On the other hand, when the starter/generator 1 is allowed to function as a generator, as shown in Fig. 10, a magnetic flux generated from each permanent magnet 62 forms a closed magnetic path together with stator salient poles and the stator core, so that an electric current proportional to the number of revolutions of the rotor can be generated in the stator windings. [0054] In this embodiment a regulated voltage from the regulator 44 is set at 14.5V, and when the starter/generator 1 is allowed to function as a generator and an output voltage obtained reaches the aforesaid regulated voltage, earth-side power FETs (Tr2, Tr4 and Tr6) out of the power FETs in the three-phase driver are short-circuited. Consequently, a short-circuit current flows at a lag phase in each stator winding 53, the magnetic lines of force passing through the stator 50 decreases, and a leaking magnetic flux connecting between adjacent permanent magnets 62 increases, resulting in that the driven torque of the starter/generator 1 decreases and so does the load on the internal combustion engine E. [0055] More specifically, as in Fig. 22 which illustrates the interior of a broken-line circle in Fig. 10 on a larger scale, between adjacent permanent magnets 62S and 62N are generated a magnetic flux B3 which passes through an outer circumferential portion 617 of the rotor yoke 61, a magnetic flux B4 which passes through an interpole 613 of the rotor yoke 61, a magnetic flux B5 which passes through an inner circumferential portion 616 of the rotor yoke 61, and a magnetic flux B6 which passes through the inner circumferential portion 616 of the rotor yoke 61, the air gap and a stator salient pole 52N. [0056] According to this embodiment, as described above, in a permanent magnet type rotary electric machine wherein the rotor yoke 61 of the outer rotor 60 has interpoles 613 each located between adjacent permanent magnets 62, there are formed clearances 612 (614) between each permanent magnet 62 and the rotor yoke 61, so a leaking magnetic flux between adjacent permanent magnets diminishes and the proportion of magnetic flux which perpendicularly intersects the air gap portion between the outer rotor 60 and the stator 50 increases. Thus, the driving torque can be increased when the permanent magnet type rotary electric machine is allowed to function as a starter motor without increasing the driven torque when the rotary electric machine is allowed to function as a generator. [0057] When the permanent magnet type rotary electric machine is allowed to function as a starter motor, as is seen from the above description and as shown in Fig. 21, the driving torque is increased by obstructing the magnetic fluxes Bl and B2 with slits (second clearances) 614A and 614B. Therefore, as shown enlargedly on the right-hand side in the same figure, the larger the width W of each slit 614, the better. [0058] On the other hand, when the permanent magnet type rotary electric machine is allowed to function as a generator, the driven torque is decreased by ensuring a sufficient magnetic path of the leaking magnetic flux B5. Therefore, as shown enlargedly on the right-hand side in the same figure, the larger the residual thickness H of the rotor yoke at the tip of each slit 614, the better. [0059] As the slit width w increases, the leaking magnetic flux B5 in Fig. 22 decreases, which is equivalent to thinning the residual thickness H. This is disadvantageous from the standpoint of decreasing the driven torque. Conversely, as the residual thickness H at the tip of each slit increases, effective components of the magnetic fluxes Bl and B2 in Fig. 21 decrease (in the amount conducted to the stator side), which is equivalent to narrowing the slit width w. This is disadvantageous from the standpoint of increasing the driving torque. Thus, increasing the slit width w to increase the driving torque and increasing the residual thickness H at the slit tip to decrease the driven torque are antinomy events and it is necessary that the ratio (H/w) of the two be set low if priority is given to increasing the driving torque and be set high if priority is given to decreasing the driven torque. [0060] Figs. 29 and 30 illustrate relations of the ratio (H/W) to the driving torque (Fig. 29) and driven torque (Fig. 30), respectively, with the residual thickness H of the rotor yoke at the tip of the second clearance (slit) 614 as parameter. In Fig. 30 it is indicated that the larger the absolute value of the driven torque, the larger the driven torque. [0061] As shown in Fig. 29, the driving torque tends to increase as the ratio (H/W) decreases, but the rate of increase becomes dull when the ratio (H/W) drops below about 0.3. On the other hand, as shown in Fig. 30, the driven torque tends to increase as the ratio (H/W) decreases, but the rate of increase increases when the ratio (H/W) drops below about 0.3. Thus, it is seen that the slit width W and the residual thickness H be set preferably not smaller than 0.3 in terms of the ratio (H/W) of the two. [0062] As shown in Fig. 30, the rate of decrease of the driven torque tends to become dull when and after the ratio (H/W) exceeds about 0.5, and the rate of decrease of the driving torque tends to become dull in the (H/W) range of 0.5 to 0.7. Thus, it is preferable to set the (H/W) ratio at a value of not larger than 0.7, and it can be said that a value of 0.5 or so is optimum. [0063] From the above experimental results it is seen that according to this embodiment both driving torque and driven torque can be made compatible with each other effectively by setting the (H/W) ratio at a value in the range of 0.3 to 0.7 and most effectively by setting the (H/W) ratio at 0.5 or thereabouts. [0064] Fig. 11 illustrates a plane shape of a rotor yoke 61a according to the second embodiment of the present invention and Fig. 12 is a partial enlarged diagram showing a state in which a permanent magnet 62a is inserted into an opening 611a formed in the rotor yoke 61a. In both figures, the same reference numerals as in the previous description represent the same or equivalent portions. [0065] In this embodiment, each opening 611a formed in the rotor yoke 61a is in a generally trapezoidal shape and a permanent magnet 62a having a rectangular section is inserted into the opening 611a. As a result, clearances 612a for preventing the leakage of magnetic flux between adjacent permanent magnets 62a are formed on both sides in the circumferential direction of each permanent magnet 62a. Also on the stator side at both ends of each permanent magnet 62a are formed clearances 614a for restricting a circumferential magnetic path. Thus, the same effects as above can be attained also in this embodiment. Also in this embodiment the ratio [Wmg:Wsp] of the width, Wmg, of each permanent magnet 62a to the width, Wsp, of each interpole 613 both in the rotational direction is set at approximately [5:1] . [0066] Fig. 13 illustrates a plane shape of a rotor yoke 61b according to the third embodiment of the present invention and Fig. 14 is a partial enlarged diagram showing a state in which a permanent magnet 62b is inserted into an opening 611b formed in the rotor yoke 61b. In both figures, the same reference numerals as in the previous description represent the same or equivalent portions. [0067] In this embodiment, each opening 611b formed in the rotor yoke 61b is like a drum of a special shape and a permanent magnet 62b having a drum-shaped section is inserted into the opening 611b. As a result, slits (first clearances) 612b for preventing the leakage of magnetic flux between adjacent permanent magnets 62b are formed on both sides in the circumferential direction of each permanent magnet 62b and also on the stator side at both ends of each permanent magnet 62b are formed slits (second clearances) 614b for restricting a circumferential magnetic path. Thus, the same effects as above are attained also in this embodiment. Also in this embodiment the ratio [Wmg:Wsp] of the width, Wmg, of each permanent magnet 62b to the width, Wsp, of each interpole 613 both in the rotational direction is set at approximately [5:1]. [0068] Fig. 15 illustrates a plane shape of a rotor yoke 61c according to the fourth embodiment of the present invention and Fig. 16 is a partial enlarged diagram showing a state in which a permanent magnet 62c is inserted into an opening 611c formed in the rotor yoke 61c. In both figures, the same reference numerals as in the previous description represent the same or equivalent portions. [0069] In this embodiment, each opening 611c formed in the rotor yoke 61c is of a special shape with cutout portions being formed on both sides of a drum-like portion, and a permanent magnet 62c having a drum-shaped section is inserted into the opening 611c. As a result, clearances 612c for preventing the leakage of magnetic flux between adjacent permanent magnets 62c are formed on both sides in the circumferential direction of each permanent magnet 62c and also on the stator side at both ends of each permanent magnet 62c there are formed clearances 614c for restricting a circumferential magnetic path. Thus, the same effects as above are obtained also in this embodiment. Also in this embodiment the ratio [Wmg:Wsp] of the width, Wmg, of each permanent magnet 62c to the width, Wsp, of each interpole 613 both in the rotational direction is set at approximately [5:1] . [0070] Fig. 17 illustrates a plane shape of a rotor yoke 61d according to the fifth embodiment of the present invention and Fig. 18 is a partial enlarged diagram showing a state in which a permanent magnet 62d is inserted into an opening 611d formed in the rotor yoke 61d. In both figures, the same reference numerals as in the previous description represent the same or equivalent portions. [0071] In this embodiment, each opening 611d formed in the rotor yoke 61d is like a drum of a special shape and a permanent magnet 62d having a drum-shaped section is inserted into the opening 611d. As a result, clearances 612d for preventing the leakage of magnetic flux between adjacent permanent magnets 62d are formed on both sides in the circumferential direction of each permanent magnet 62d. [0072] Further, separately from the opening 611d, clearances 614d for restricting a circumferential magnetic path are formed like cutouts in inner peripheral portions of the rotor yoke 61d corresponding to both ends of each permanent magnet 62d. Therefore, the same effects as above are obtained also in this embodiment. Also in this embodiment the ratio [Wmg:Wsp] of the width, Wmg, of each permanent magnet 62d to the width, Wsp, of each interpole 613 both in the rotational direction is set at approximately [5:1]. [0073] Fig. 19 illustrates a plane shape of a rotor yoke 61e according to the sixth embodiment of the present invention and Fig. 20 is a partial enlarged diagram showing a state in which a permanent magnet 62e is inserted into an opening 611e formed in the rotor yoke 61e. In both figures, the same reference numerals as in the previous description represent the same or equivalent portions. [0074] In this embodiment, each opening 611e formed in the rotor yoke 61e is like a drum of a special shape and a permanent magnet 62e having a drum-shaped section is inserted into each opening 611e. As a result, clearances 612e for preventing the leakage of magnetic flux between adjacent permanent magnets 62e are formed on both sides in the circumferential direction of each permanent magnet 62e and also on the stator side at both ends of each permanent 62e there are formed clearances 614e for restricting a circumferential magnetic path. Thus, the same effects as above are obtained also in this embodiment. Also in this embodiment the ratio [Wmg:Wsp] of the width, Wmg, of each permanent magnet 62e to the width, Wsp, of each interpole 613 both in the rotational direction is set at approximately [5:1]. [0075] [Effects of the Invention] According to the present invention, as described hereinabove, in a permanent magnet type rotary electric machine wherein a rotor yoke of an outer rotor has interpoles each located between adjacent permanent magnets, both driving and driven torques can be made compatible with each other effectively. Therefore, it is possible increase the driving torque when the permanent magnet type rotary electric machine is allowed to function as a starter motor without increasing the driven torque when the rotary electric machine is allowed to function as a generator. [0076] According to the present invention, as described hereinabove, in a permanent magnet type rotary electric machine wherein a rotor yoke of an outer rotor has interpoles each located between adjacent permanent magnets, the ratio [Wmg:Wsp] of the width, Wmg, of each of the permanent magnets to the width, Wsp, of each of the interpoles both in the rotational direction is optimized and the advance angle of an alternating current to be fed to each phase terminal is optimized on the basis of the width, Wsp, of each interpole in the rotational direction. Therefore, when the permanent magnet type rotary electric machine is allowed to function as an electric motor, there is attained an improvement of torque particularly in a low rotation region, while when the rotary electric machine is allowed to function as a generator, it is possible to diminish friction in a high rotation region. [Explanation of Reference Numerals] 1 ... starter/generator, 50 ... stator, 51 ... stator core, 52 ... stator salient pole, 53 ... stator winding, 60 ... outer rotor, 61 ... rotor yoke, 62 (62N, 62S) ... permanent magnet, 63 ... rotor case, 71 ... protective cover, 201 ... crank shaft, 611 ... opening, 612 ... slit (first clearance), 613 . . . interpole, 614 . . . slit (second clearance) WE CLAIM : 1. A permanent magnet type rotary electric machine wherein a rotor yoke of a generally cylindrical shape adapted to rotate along an outer periphery of a stator is formed with a plurality of magnet inserting holes in a circumferential direction thereof alternately with interpoles, and permanent magnets are inserted into said magnet inserting holes, respectively, characterized in that: said magnetic inserting holes each comprises a main opening for insertion therein of each of said permanent magnets and slits extending with a predetermined width (W) toward a central portion from both end portions in the circumferential direction of said main opening, and a residual thickness (H) of the rotor yoke at the tip of each said slit and said slit width (W) satisfy the relationship of 0.3 wherein said permanent magnet type rotary electric machine comprises a control unit which feeds an exciting current from a battery to each stator winding at a rotational speed lower than a predetermined rotational speed, and is driven by the internal combustion engine at a rotational speed not lower than a predetermined rotational speed. 2. A permanent magnet type rotary electric machine as claimed in claim 1, wherein the residual thickness (H) /slit width (W) is approximately 0.5. 3. A permanent magnet type rotary electric machine wherein a rotor yoke of a generally cylindrical shape adapted to rotate along an outer periphery of a stator is formed with a plurality of magnet inserting holes in a circumferential direction thereof alternately with interpoles, and permanent magnets are inserted into said magnet inserting holes, respectively, wherein the ratio (Wmg:Wsp) of the width, Wmg, of each said permanent magnet to the width, Wsp, of each said interpole both in a rotational direction is approximately (5:1). 4. A permanent magnet type rotary electric machine as claimed in claim 3, said permanent magnet type rotary electric machine comprises a control unit which feeds an exciting current from a battery to each stator winding at a rotational speed lower than a predetermined rotational speed, and is driven by the internal combustion engine at a rotational speed not lower than a predetermined rotational speed. 5. A drive unit for a permanent magnet type rotary electric machine wherein a rotor yoke of a generally cylindrical shape adapted to rotate along an outer periphery of a stator is formed with a plurality of magnet inserting holes in a circumferential direction thereof alternatively with interpoles, and permanent magnets are inserted into said magnet inserting holes, respectively, wherein the phase of an alternating current to be fed to each phase terminal of said permanent magnet type rotary electric machine is advanced by an angle corresponding to 1 to 1.5 times the width, Wsp, of each said interpole in a rotational direction. 6. A permanent magnet type rotary electric machine substantially as hereinbefore described with reference to the accompanying drawings. Dated this 3rd day of August,2001.

Full Text

ORIGINAL
746/MUM/2001
205062
FORM 2
THE PATENTS ACT 1970
[39 OF 1970]
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See Section 10; rule 13]
"PERMANENT MAGNET TYPE ROTARY ELECTRIC MACHINE AND DRIVE UNIT FOR SAME"
HONDA GIKEN KOGYO KABUSHIKl KAISHA, a corporation of Japan, having a place of business at 1-1, Minamiaoyama 2-chome, Minato-ku, Tokyo, Japan,
The following specification particularly describes the invention and the manner in which it is to be performed:

GRANTED

3 MAR 2006
3-3-2006

The present invention relates to permanent magnet type rotaiy electric machine and drive unit for same.
The present invention relate to a permanent magnet type rotary electric machine wherein a rotor yoke having a plurality of permanent magnets arranged in a circumferential direction thereof is adapted to rotate along an outer periphery of a stator, as well as a drive unit for the same. Particularly, the invention is concerned with a permanent magnet type rotary electric

machine wherein the rotor yoke have interpoles alternately with permanent magnets, as well as a drive unit for the same.
[0002]
[Prior Art]
Heretofore, a starter motor and a generator both for an internal combustion engine have been provided separately from each other, but a starter/generator having the respective functions in an integrated state is disclosed, for example, in Japanese Patent Laid-open No. Hei 10-148142.
[0003]
On the other hand, as a starter motor for an internal combustion engine there is known an outer rotation, permanent magnet type rotary electric machine wherein a cylindrical rotor yoke rotates along an outer periphery of a stator. Further, for example in Japanese Patent Laid-open No. Hei 8-275476 there is disclosed such a permanent magnet type rotary electric machine wherein interpoles are formed so as to be each positioned between adjacent permanent magnets to mitigate a strain of a magnetic flux distribution between a rotor and a stator and thereby prevent the occurrence of torque oscillation.
[0004]

[Problems to be Solved by the Invention]
In the conventional permanent magnet type rotary electric machine described above, between permanent magnets adjacent to each other with an interpole therebetween there occurs a leaking magnetic flux with the interpole as a magnetic path and hence an effective magnetic flux diminishes. Therefore, if it is intended to obtain a larger amount of driving torque, it is necessary to increase the size of each permanent magnet used or increase an exciting current for a stator winding. But an increase in size and weight of the motor or an increase in power consumption results. [0005]
Further, where it is intended to let one motor function as a starter motor at the time of starting an internal combustion engine and also function as a generator during travel of the vehicle concerned, an increase in size of permanent magnets will afford a large driving force if the motor is allowed to function as a starter motor, but larger electric power than necessary will be generated if the motor is allowed to function as a generator, thus resulting in an increase of torque (driven torque) which the internal combustion engine, indicated at E, requires for driving a starter/generator.

[0006]
In the conventional permanent magnet type rotary electric machine described above, the ratio [Wmg:Wsp] of the width, Wmg, of each permanent magnet to the width, Wsp, of each interpole both in the rotational direction exerts a great influence on the torque in a low rotation region particularly when the electric machine is allowed to function as an electric motor. In the foregoing prior art, however, no consideration is given to an appropriate relation of the ratio [Wmg:Wsp] to an increase of friction when the permanent magnet type rotary electric machine is allowed to function as a generator.
[0007]
Further, in the permanent magnet type rotary electric machine of the structure described above, since the interposes function as part of the permanent magnets, it is desirable that the supply of an electric current to the rotary electric machine be advanced by an angle corresponding to the width Wsp of each interpole. In the foregoing prior art, however, no consideration is given to an appropriate relation between the interloped width Wsp and the advance angle.
[0008]
It is a first object of the present invention to

solve the above-mentioned technical problems of the prior art and provide a permanent magnet type rotary electric machine as a starter/generator capable of affording a large driving torque when it is allowed to function as a starter motor and diminishing a driven torque when allowed to function as a generator.
[0009]
It is a second object of the present invention to solve the above-mentioned problems of the prior art and provide a permanent magnet type rotary electric machine having an optimum ration [Wmg:Wsp] of the permanent magnet width Wmg to the Interpol width Wsp.
[0010]
It is a third object of the present invention to solve the above-mentioned problems of the prior art and provide a drive unit for a permanent magnet type rotary electric machine having an optimum relation between the Interpol width Wsp and the advance angle in the supply of an electric current.
[0011] [Means for Solving the Problems]
According to the present invention, for achieving the first object, there is provided a permanent magnet type rotary electric machine wherein a rotor yoke of a

generally cylindrical shape adapted to rotate along an outer periphery of a stator is formed with a plurality of magnet inserting holes in a circumferential direction thereof alternately with interposes, and permanent magnets are inserted into the magnet inserting holes, respectively, characterized in that the magnet inserting holes each comprise a main opening for insertion therein of each of the permanent magnets and slits (first clearances) extending with a predetermined width (w) toward a central portion from both end portions in the circumferential direction of the main opening, and a residual thickness (H) of the rotor yoke at the tip of each of the slits and the slit width (W) satisfy the relationship of 0.3 Widening the slit width (W) is equivalent to thinning the residual thickness (H), which is disadvantageous from the standpoint of decreasing the driven torque. Conversely, increasing the residual thickness (H) is disadvantageous from the standpoint of increasing the driving torque. Thus, widening the slit width (W) to increase the driving torque and increasing the residual thickness H of the rotor yoke to decrease

The driven torqueses are antinomy events. If priority is given to increasing the driving torque, the ratio (H/W) of the two must be set low, while if priority is given to decreasing the driven torque, the ratio (H/W) must be set high. However, if 0.3 [0013]
For achieving the second and third objects the present invention is characterized by adopting the following means.
[0014] (1) In a permanent magnet type rotary electric machine wherein a rotor yoke of a generally cylindrical shape adapted to rotate along an outer periphery of a stator is formed with a plurality of magnet inserting holes in a circumferential direction thereof alternately with interposes, and permanent magnets are inserted into the magnet inserting holes, respectively, a feature resides in that the ratio [Wmg:Wsp] of the width, Wmg, of each of the permanent magnets to the width, Wsp, of each of the interposes both in a rotational direction is approximately [5:1].
[0015]

(2) In a drive unit for a permanent magnet type rotary electric machine wherein a rotor yoke of a generally cylindrical shape adapted to rotate along an outer periphery of a stator is formed with a plurality of magnet inserting holes in a circumferential direction thereof alternately with interposes, and permanent magnets are inserted into the magnet inserting holes, respectively, a feature resides in that the phase of an alternating current to be fed to each phase terminal of the permanent magnet type rotary electric machine is advanced by an angle corresponding to 1 to 1.5 times the width, Wsp, of each Interpol in a rotational direction. [0016]
According to the above features, not only the improvement of torque is attained particularly in a low rotation region when the permanent magnet type rotary electric machine is allowed to function as an electric motor, but also the friction is diminished when the rotary electric machine is allowed to function as a generator. Thus, it is possible to realize a well-balanced rotary electric machine. [0017] [Mode for Carrying Out the Invention]
The present invention will be described below in

Detail with reference to the drawings.
The present invention relates to a permanent magnet type rotary electric machine wherein a rotor yoke of a generally cylindrical shape adapted to rotate along an outer periphery of a stator is formed with a plurality of magnet inserting holes in a circumferential direction thereof alternately with interposes, and permanent magnets are inserted into said magnet inserting holes, respectively, characterized in that:
said magnetic inserting holes each comprises a main opening for insertion therein of each of said permanent magnets and slits extending with a predetermined width (W) toward a central portion from both end portions in the circumferential direction of said main opening, and a residual thickness (H) of the rotor yoke at the tip of each said slit and said slit width (W) satisfy the relationship of 0.3 Wherein said permanent magnet type rotary electric machine comprises a control unit which feeds an exciting current from a battery to each stator winding at a rotational speed lower than a predetermined rotational speed, and is driven by the internal combustion engine at a rotational speed not lower than a predetermined rotational speed.
[BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS]
[FIG. 1]
Fig 1 is an entire side view of a scooter type two -wheeled motor vehicle in which a permanent magnet type rotary electric machine embodying the present invention is applied to a starter/generator.
[FIG. 2]
Fig. 2 is a sectional view of a swing unit shown in Fig. 1, taken a crank shaft.
[FIG. 3]
Fig. 3 is a partially cut-away plan view taken along a plane perpendicular to a rotary shaft (crank shaft) of the starter/ generator (the permanent magnetic type rotary electric machine).
[FIG. 4]
Fig. 4 is a sectional side view of Fig. 3.

[Fig. 5]
Fig. 5 is a plan view of a rotor yoke. [Fig. 6]
Fig. 6 is a side view of the rotor yoke. [Fig. 7]
Fig. 7 is a partial enlarged view of the rotor yoke [Fig. 8]
Fig. 8 is a block diagram of a control system used in the starter/generator. [Fig. 9]
Fig. 9 is a diagram for explaining the function (as a starter motor) of slits and clearances formed in the rotor yoke. [Fig. 10]
Fig. 10 is a diagram for explaining the function (as a generator) of the slits and clearances formed in the rotor yoke. [Fig. 11]
Fig. 11 is a diagram showing a plane shape of a rotor yoke according to the second embodiment of the present invention. [Fig. 12]
Fig. 12 is a partial enlarged diagram showing a state in which a permanent magnet is inserted into an

Opening shown in Fig. 11. [Fig. 13]
Fig. 13 is a diagram showing a plane shape of a rotor yoke according to the third embodiment of the present invention. [Fig. 14]
Fig. 14 is a partial enlarged diagram showing a state in which a permanent magnet is inserted into an opening shown in Fig. 13. [Fig. 15]
Fig. 15 is a diagram showing a plane shape of a rotor yoke according to the fourth embodiment of the present invention. [Fig. 16]
Fig. 16 is a partial enlarged diagram showing a state in which a permanent magnet is inserted into an opening shown in Fig. 15. [Fig. 17]
Fig. 17 is a diagram showing a plane shape of a rotor yoke according to the fifth embodiment of the present invention. [Fig. 18]
Fig. 18 is a partial enlarged diagram showing a state in which a permanent magnet is inserted into an

Opening shown in Fig. 17. [Fig. 19]
Fig. 19 is a diagram showing a plane shape of a rotor yoke according to the sixth embodiment of the present invention. [Fig. 20]
Fig. 20 is a partial enlarged diagram showing a state in which a permanent magnet is inserted into an opening shown in Fig. 19. [Fig. 21]
Fig. 21 is a partial enlarged diagram of Fig. 9. [Fig. 22]
Fig. 22 is a partial enlarged diagram of Fig. 10. [Fig. 23]
Fig. 23 is a diagram showing a relation between an advance angle of a power supply timing and torque in 120° power supply control with rotor revolutions as a parameter ([Wmg:Wsp] is about [5:1]). [Fig. 24]
Fig. 24 is a diagram showing a relation between an advance angle of a power supply timing and torque in 120° power supply control with rotor revolutions as a parameter ([Wmg:Wsp] is about [4:1]). [Fig. 25]

Fig. 25 a diagram showing a relation between an advance angle of a power supply timing and torque in 12 0° power supply control with rotor revolutions as a parameter ([Wmg:Wsp] is about [2.8:1]). [Fig. 26]
Fig. 26 is a diagram showing a relation between an advance angle of a power supply timing and torque in 180° power supply control with rotor revolutions as a parameter ([Wmg:Wsp] is about [5:1]). [Fig. 27]
Fig. 27 is a diagram showing a relation between an advance angle of a power supply timing and torque in 180° power supply control with rotor revolutions as a parameter ([Wmg:Wsp] is about [4:1]). [Fig. 28]
Fig. 28 is a diagram showing a relation between an advance angle of a power supply timing and torque in 180° power supply control with rotor revolutions as a parameter ([Wmg:Wsp] is about [2.8:1]). [Fig. 29]
Fig. 29 is a diagram showing a relation between the ratio (H/W) of a residual thickness H of a rotor yoke at the tip of a slit to the slit width W and a driving torque.

[Fig. 30]
Fig. 30 is a diagram showing a relation between
said ratio (H/W) and a driven torque.

Fig. 1 is a .............................................................................. entire side view of a scooter type two-wheeled motor vehicle in which a permanent magnet type rotary electric machine according to the present invention is applied to a starter/generator. [0018]
A front body portion 3a and a rear body portion 3b are connected together through a low floor portion 4, and a body frame which constitutes a skeleton of the vehicle body is substantially composed of a down-tube 6 and a main pipe 7. A fuel tank and a receptacle box (neither shown) are supported by the main pipe 7 and a seat 8 is disposed there above. [0019]
In the front body portion 3a, a handle 11 is provided at an upper position in a pivotally supported state by a steering head 5, while a front fork 12 extends downward, with a front wheel FW being supported at a lower end of the front fork through an axle. An upper portion of the handle 11 is covered with a handle cover 13 which also serves as an instrument board. A bracket 15 is projecting provided on a lower end of a rise portion of the main pipe 7 and a hanger bracket 18 of a swing unit 2 is connected to the bracket 15 swing ably through a

link member 16.
[0020]
On a front portion of the swing unit 2 is mounted a single-cylinder two-stroke internal combustion engine E, and a belt type continuously variable transmission 26 is constituted backward from the internal combustion engine E. A reduction mechanism 27 is connected to a rear portion of the continuously variable transmission 26 through a centrifugal clutch and a rear wheel RW is supported by the reduction mechanism 27 through an axle. A rear cushion 22 is interposed between an upper end of the reduction mechanism 27 and an upper bent portion of the main pipe 7. On the front side of the swing unit 2 are disposed a carburetor 24 connected to an intake pipe 23 extending from the internal combustion engine E and an air cleaner 25 connected to the carburetor 24.
[0021]
Fig. 2 is a sectional view of the swing unit 2 taken along a crank shaft 201, in which the same reference numerals as in the above description represent the same or equivalent portions.
[0022]
The swing unit 2 is covered with a crank case 202 which is constituted by a combination of left and right

Crank cases 202L, 202R. The crank shaft 201 is supported rotatably by bearings 208 and 209 which are fixed to the crank case 202R. To the crank shaft 201 is connected a connecting rod (not shown) through a crank pin 213.
[0023]
The left crank case 202L also serves as a belt type continuously variable transmission case, and a belt driving pulley 210 is mounted rotatably on the crank shaft 201 extending up to the left crank case 202L. The belt driving pulley 210 comprises a fixed pulley half 210L and a movable pulley half 210R. The fixed pulley half 210L is fixed to a left-end portion of the crank shaft 201 through a boss 211, while on the right-hand side of the fixed pulley half 210L the movable pulley half 210R is spilled to the crank shaft 201 so as to be movable toward and away from the fixed pulley half 210L, with V belt 212 being entrained between both pulley halves 210L and 210R.
[0024]
On the right-hand side of the movable pulley half 210R a cam plate 215 is fixed to the crank shaft 201 and a slide piece 215a provided at an outer peripheral end of the cam plate 215 is slidably engaged with a cam plate sliding boss portion 210Ra which is formed axially at an

Outer periphery ends of the movable pulley half 210R. The cam plate 215 located on the right-hand side of the movable pulley half 210R has a tapered surface inclined toward the movable pulley half 210R at a portion thereof close to its outer periphery, and a dry weight ball 216 is accommodated within a space formed between the said tapered surface and the movable pulley half 210R.
[0025]
As the rotational speed of the crank shaft 201 increases, the dry weight ball 216, which is located between the movable pulley half 210R and the cam plate 215 and is adapted to rotate accordingly, moves in a centrifugal direction under the action of a centrifugal force, so that the movable pulley half 210R is pushed by the dry weight ball 216, moves leftwards and approaches the fixed pulley half 210L. As a result, the V belt 212 sandwiched in between both pulley halves 210L and 210R moves in the centrifugal direction and its winding diameter becomes larger.
[0026]
In a rear portion of the vehicle is installed a driven pulley (not shown) mating with the belt driving pulley 210 and the V belt 212 is entrained on the driven pulley. With this belt transfer mechanism, the power from

The internal combustion engine E is adjusted automatically and is transmitted to a centrifugal clutch to drive the rear wheel RW through the reduction mechanism 27, etc.
[0027]
Within the right crank case 202R is disposed a starter/generator 1 as a combination of a starter motor and an AC generator. In the starter/generator 1, an outer rotor 60 is fixed with screw 253 onto a tapered end portion of the crank shaft 201. An inner stator 50, which is disposed inside the outer rotor 60, is threadedly secured to the crank case 202 with a bolt 279 and is supported thereby. As to the construction of the starter/generator, it will be described later in detail with reference to Figs. 3 to 7.
[0028]
A fan 280 has a central conical portion 280a, a skirt portion of which is fixed to the outer rotor 60 with a bolt 246. The fan 280 is covered with a fan cover 281 through a radiator 282.
[0029]
A sprocket 231 is fixed onto the crank shaft 201 at a position between the starter/generator 1 and the bearing 209 and a chain is entrained on the sprocket 231

to drive a cam shaft (not shown) from the crank shaft 201. The sprocket 231 is integral with a gear 232 which is for the transfer of power to a lubricant oil circulating pump.
[0030]
Figs. 3 and 4 are a partially cut-away plan view and a sectional side view thereof taken along a plane perpendicular to the rotational shaft (crank shaft 201) of the starter/generator 1 (a permanent magnet type rotary electric machine), and Figs. 5 and 6 are a plan view of a rotor yoke and a partial enlarged view thereof, respectively. In these figures, the same reference numerals as in the previous description represent the same or equivalent portions.
[0031]
As shown in Figs. 3 and 4, the starter/generator 1 of this embodiment is made up of the stator 50 and the outer rotor 60 adapted to rotate along the outer periphery of the stator 50. The outer rotor 60 is made up of a rotor yoke 61 constituted by stacking ring-like silicon steel sheets (thin sheets) in a generally cylindrical shape, as shown in Figs. 4 and 5, N-pole permanent magnets 62N and S-pole permanent magnets 62S inserted alternately into plural openings 611 formed in the circumferential direction of the rotor yoke 61, as

shown in Figs. 3 and 7, and a cup-like rotor case 63 which connects the rotor yoke 61 to the crank shaft 201, as shown in Figs. 3 and 4.
[0032]
The rotor case 63 is formed with a pawl portion 63a along its circumferential end portion. By bending the pawl portion 63a inwards the rotor yoke 61 of the stacked structure described above is held grippingly and the permanent magnets 62 (62N, 62S) inserted respectively into the openings 611 of the rotor yoke are held at predetermined positions in the rotor yoke 61.
[0033]
The stator 50 is constituted by stacking silicon steel sheets (thin sheets) and includes a stator core 51 and stator salient poles 52, as shown in Fig. 3. A stator winding 53 is wound round each stator salient pole 52 in a single pole concentrated manner and a main surface of the stator 50 is covered with a protective cover 71.
[0034]
In the rotor yoke 61, as shown in Figs. 5 and 6, twelve openings 611, into which the permanent magnets 62 are inserted axially, are formed circumferentially at intervals of 30°. In both circumferential ends of each opening 611 are formed slits (second clearances) 614 with

a predetermined width toward a central portion. The portion between adjacent openings 611 functions as an interpole 613. Into each of the openings 611 is inserted a permanent magnet 62 of a generally drum-like section, as shown in Fig. 7. The ratio [Wmg:Wsp] of the width of each opening 611, i.e., the width, Wmg, of each permanent magnet 62 to the width, Wsp, of each interpole 613 is set at approximately [5:1], as shown in Fig. 6.
[0035]
Into each of the openings 611 is inserted a permanent magnet 62 of a generally drum-like section, as shown in Fig. 7. In this embodiment, the shape of each opening 611 and the sectional shape of each permanent magnet 62 are not the same, but when the permanent magnet 62 is inserted into the opening 611, slits (first clearances) 612 are formed on both sides in the circumferential direction of each permanent magnet 62 and the slits 614 are left on the stator side at both ends of each permanent magnet 62.
[0036]
Fig. 8 is a block diagram of a control system used in the starter/generator 1, in which the same reference numerals as in the above description represent the same or equivalent portions.

[0037]
A control unit 40 includes a DC-DC converter 102 which converts an output voltage VBATT of a battery 42 into a logic voltage VDD and supplies the logic voltage VDD to a CPU 101, an ignition controller 103 which controls the supply of electric current to an IG coil 41 and causes a spark plug 43 to spark at a predetermined timing, and a three-phase driver 104 which converts the battery voltage VBATT into three-phase AC power and supplies it to the stator windings 53.
[0038]
A throttle sensor 45 detects a throttle opening 6 th and notifies the CPU 101 of the result. Likewise, a rotor sensor 46 detects a rotational position of the outer rotor 60 and notifies the CPU 101 of the result. Further, a regulator 44 controls an induced electromotive force to be generated in the stator windings 53 into a predetermined battery voltage VBATT in accordance with rotation of the outer rotor 60.
[0039]
In such a configuration, when starting an engine, the CPU 101 determines an excitation timing for the stator windings 53 on the basis of the rotational position of the outer rotor 60 detected by the rotor

sensor 46, controls a switching timing of each power FET in the three-phase driver 104 and supplies AC power to each phase of the stator winding 53.
[0040]
Each of power FETs (Trl~Tr6) in the three-phase driver 104 is PwM-controlled by the CPU 101 and a duty ratio, or a driving torque, thereof is controlled in accordance with the number of revolutions of the outer rotor 60.
[0041]
On the other hand, upon start-up of the internal combustion engine E, the supply of electric power from the three-phase driver 104 to the stator windings 53 is stopped, and then starter/generator 1 is driven by the internal combustion engine E. At this time, an electromotive force is generated in the stator windings 53 in accordance with the rotational speed of the crank shaft 201. This electromotive force is controlled to the battery voltage VBATT by the regulator 44 and is fed to each electric load, while surplus electric power is charged to the battery 42.
[0042]
Figs. 23, 24 and 25 each illustrate a relation between an advance degree (°) of a power supply timing

and torque (N/m) with rotor revolutions (rpm) as a parameter in 120° power supply control. In Figs. 23, 24, and 25, the ratios [Wmg:Wsp] of the width, Wmg, of each permanent magnet 62 to the width, Wsp, of each interpole 613 are approximately [5:1], [4:1], and [2.8:1], respectively. [0043]
In the example shown in Fig. 23 in which the ratio
[Wmg:Wsp] is approximately [5:1], high torques are generated at advance degrees in the range of 5' to 7 * or 8° regardless of whether the number of revolutions of the rotor is large or small. On the other hand, in the examples shown in Figs. 24 and 25 in which the ratios
[Wmg:Wsp] are approximately [4:1] and [2.8:1], respectively, the drop of torque becomes conspicuous as the advance degree is increased when the number of revolutions of the rotor is small (40 rpm). [0044]
Figs. 26, 27 and 28 each illustrate a relation between an advance degree (*) of a power supply control and torque (N/m) with rotor revolutions (rpm) as a parameter. In Figs. 26, 27, and 28, the ratios [Wmg:Wsp] of the width, Wmg, of each permanent magnet 62 to the width, Wsp, of each interpole 613 are approximately [5:1],

[4:1], and [2.8:1], respectively.
[0045]
In the example shown in Fig. 26 in which the ratio [wmg:wsp] is approximately [5:1], high torques are generated at advance degrees in the range of 5' to 7' or 8° particularly when the number of revolutions of the rotor is small. On the other hand, in the examples shown in Figs. 27 and 28 in which the ratios [wmg:wsp] are approximately [4:1] and [2.8:1], respectively, torques generated at small rotor revolutions are inferior in comparison with the example shown in Fig. 26 in which the ratio [Wmg:Wsp] is approximately [5:1].
[0046]
Thus, according to the results of experiments made by the inventor it is seen that in both 120° and 180" power supply controls high torques are obtained particularly in a low rotation region of the rotor when the ratio [wmg:Wsp] of the width, wmg, of each permanent magnet 62 to the width, wsp, of each interpole 613 is approximately [5:1]. It is also seen that a high torque is obtained if the advance degree is set at a value in the range of 5° to 7' or 8°, i.e., at a value 1 to 1.5 times the angle (5° in this embodiment) of each interpole 613.

[0047]
No ith reference to Figs. 9 and 10, a description will be given below of the operation of the slits 614 formed in the rotor yoke 61 and the clearances 612 formed between the rotor yoke 61 and the permanent magnets 62.
[0048]
Fig. 9 illustrates a magnetic flux density distribution obtained when the starter/generator 1 is allowed to function as a starter motor, while Fig. 10 illustrates a magnetic flux density distribution obtained when the starter/generator 1 is allowed to function as a generator.
[0049]
When the starter/generator 1 is allowed to function as a starter motor, if an exciting current is fed from the battery 42 to each stator winding 53 through the control unit 40, as shown in Fig. 9, magnetic lines of force generated in a radial direction from each N-magnetized stator salient pole 52N pass through the back from the stator-side surface of each S-pole permanent magnet 62S and many of them passes through a core portion 615 of the rotor yoke 61 and an interpole 613, then further passes through an adjacent S-magnetized stator

salient pole 52S and the stator core 51, and returns to the N-magnetized stator salient pole 52N.
[0050]
In this case, since in this embodiment clearances 612 are formed on both sides of in the circumferential direction of each permanent magnet 62 and magnetic flux leaking from side portions of each permanent magnet 62 to the interpole 613 side is diminished thereby, most of the magnetic lines of force pass from each permanent magnet 62 to the core portion 615 of the rotor yoke 61 and reach the stator 50 side via the interpoles 613. As a result, a vertical component of the magnetic flux passing through the air gap between the outer rotor 60 and the stator 50 increases, so that it becomes possible to increase the driving torque in comparison with the case where the clearances 612 are not formed.
[0051]
Further, since in this embodiment slits 614 for limiting a magnetic path in the circumferential direction are also formed on the stator side at both end portions of each permanent magnet 62, leaking magnetic flux which passes the inside of the rotor yoke 61 also diminishes.
[0052]
More specifically, as in Fig. 21 which illustrates

the interior of a broken-line circle in Fig. 9 on a larger scale, one (614A) of the slits (second clearances) 614 acts to conduct a magnetic flux Bl efficiently from an interpole 613 of the rotor yoke 61 to the stator salient pole 52S. The other (614B) of the clearances 614 acts to conduct a magnetic flux B2 to the stator salient pole 52S efficiently, the magnetic flux B2 passing through the inner circumferential portion 616 of the rotor yoke 61 from the permanent magnet 62N. As a result, a vertical component of magnetic flux passing through the air gap between the outer rotor 60 and the stator 50 further increases and it becomes possible to further increase the driving torque as the starter motor.
[0053]
On the other hand, when the starter/generator 1 is allowed to function as a generator, as shown in Fig. 10, a magnetic flux generated from each permanent magnet 62 forms a closed magnetic path together with stator salient poles and the stator core, so that an electric current proportional to the number of revolutions of the rotor can be generated in the stator windings.
[0054]
In this embodiment a regulated voltage from the regulator 44 is set at 14.5V, and when the

starter/generator 1 is allowed to function as a generator and an output voltage obtained reaches the aforesaid regulated voltage, earth-side power FETs (Tr2, Tr4 and Tr6) out of the power FETs in the three-phase driver are short-circuited. Consequently, a short-circuit current flows at a lag phase in each stator winding 53, the magnetic lines of force passing through the stator 50 decreases, and a leaking magnetic flux connecting between adjacent permanent magnets 62 increases, resulting in that the driven torque of the starter/generator 1 decreases and so does the load on the internal combustion engine E. [0055]
More specifically, as in Fig. 22 which illustrates the interior of a broken-line circle in Fig. 10 on a larger scale, between adjacent permanent magnets 62S and 62N are generated a magnetic flux B3 which passes through an outer circumferential portion 617 of the rotor yoke 61, a magnetic flux B4 which passes through an interpole 613 of the rotor yoke 61, a magnetic flux B5 which passes through an inner circumferential portion 616 of the rotor yoke 61, and a magnetic flux B6 which passes through the inner circumferential portion 616 of the rotor yoke 61, the air gap and a stator salient pole 52N.

[0056]
According to this embodiment, as described above, in a permanent magnet type rotary electric machine wherein the rotor yoke 61 of the outer rotor 60 has interpoles 613 each located between adjacent permanent magnets 62, there are formed clearances 612 (614) between each permanent magnet 62 and the rotor yoke 61, so a leaking magnetic flux between adjacent permanent magnets diminishes and the proportion of magnetic flux which perpendicularly intersects the air gap portion between the outer rotor 60 and the stator 50 increases. Thus, the driving torque can be increased when the permanent magnet type rotary electric machine is allowed to function as a starter motor without increasing the driven torque when the rotary electric machine is allowed to function as a generator.
[0057]
When the permanent magnet type rotary electric machine is allowed to function as a starter motor, as is seen from the above description and as shown in Fig. 21, the driving torque is increased by obstructing the magnetic fluxes Bl and B2 with slits (second clearances) 614A and 614B. Therefore, as shown enlargedly on the right-hand side in the same figure, the larger the width

W of each slit 614, the better.
[0058]
On the other hand, when the permanent magnet type rotary electric machine is allowed to function as a generator, the driven torque is decreased by ensuring a sufficient magnetic path of the leaking magnetic flux B5. Therefore, as shown enlargedly on the right-hand side in the same figure, the larger the residual thickness H of the rotor yoke at the tip of each slit 614, the better.
[0059]
As the slit width w increases, the leaking magnetic flux B5 in Fig. 22 decreases, which is equivalent to thinning the residual thickness H. This is disadvantageous from the standpoint of decreasing the driven torque. Conversely, as the residual thickness H at the tip of each slit increases, effective components of the magnetic fluxes Bl and B2 in Fig. 21 decrease (in the amount conducted to the stator side), which is equivalent to narrowing the slit width w. This is disadvantageous from the standpoint of increasing the driving torque. Thus, increasing the slit width w to increase the driving torque and increasing the residual thickness H at the slit tip to decrease the driven torque are antinomy events and it is necessary that the ratio (H/w) of the

two be set low if priority is given to increasing the driving torque and be set high if priority is given to decreasing the driven torque.
[0060]
Figs. 29 and 30 illustrate relations of the ratio (H/W) to the driving torque (Fig. 29) and driven torque (Fig. 30), respectively, with the residual thickness H of the rotor yoke at the tip of the second clearance (slit) 614 as parameter. In Fig. 30 it is indicated that the larger the absolute value of the driven torque, the larger the driven torque.
[0061]
As shown in Fig. 29, the driving torque tends to increase as the ratio (H/W) decreases, but the rate of increase becomes dull when the ratio (H/W) drops below about 0.3. On the other hand, as shown in Fig. 30, the driven torque tends to increase as the ratio (H/W) decreases, but the rate of increase increases when the ratio (H/W) drops below about 0.3. Thus, it is seen that the slit width W and the residual thickness H be set preferably not smaller than 0.3 in terms of the ratio (H/W) of the two.
[0062]
As shown in Fig. 30, the rate of decrease of the

driven torque tends to become dull when and after the ratio (H/W) exceeds about 0.5, and the rate of decrease of the driving torque tends to become dull in the (H/W) range of 0.5 to 0.7. Thus, it is preferable to set the (H/W) ratio at a value of not larger than 0.7, and it can be said that a value of 0.5 or so is optimum.
[0063]
From the above experimental results it is seen that according to this embodiment both driving torque and driven torque can be made compatible with each other effectively by setting the (H/W) ratio at a value in the range of 0.3 to 0.7 and most effectively by setting the (H/W) ratio at 0.5 or thereabouts.
[0064]
Fig. 11 illustrates a plane shape of a rotor yoke 61a according to the second embodiment of the present invention and Fig. 12 is a partial enlarged diagram showing a state in which a permanent magnet 62a is inserted into an opening 611a formed in the rotor yoke 61a. In both figures, the same reference numerals as in the previous description represent the same or equivalent portions.
[0065]
In this embodiment, each opening 611a formed in the

rotor yoke 61a is in a generally trapezoidal shape and a permanent magnet 62a having a rectangular section is inserted into the opening 611a. As a result, clearances 612a for preventing the leakage of magnetic flux between adjacent permanent magnets 62a are formed on both sides in the circumferential direction of each permanent magnet 62a. Also on the stator side at both ends of each permanent magnet 62a are formed clearances 614a for restricting a circumferential magnetic path. Thus, the same effects as above can be attained also in this embodiment. Also in this embodiment the ratio [Wmg:Wsp] of the width, Wmg, of each permanent magnet 62a to the width, Wsp, of each interpole 613 both in the rotational direction is set at approximately [5:1] .
[0066]
Fig. 13 illustrates a plane shape of a rotor yoke 61b according to the third embodiment of the present invention and Fig. 14 is a partial enlarged diagram showing a state in which a permanent magnet 62b is inserted into an opening 611b formed in the rotor yoke 61b. In both figures, the same reference numerals as in the previous description represent the same or equivalent portions.
[0067]

In this embodiment, each opening 611b formed in the rotor yoke 61b is like a drum of a special shape and a permanent magnet 62b having a drum-shaped section is inserted into the opening 611b. As a result, slits (first clearances) 612b for preventing the leakage of magnetic flux between adjacent permanent magnets 62b are formed on both sides in the circumferential direction of each permanent magnet 62b and also on the stator side at both ends of each permanent magnet 62b are formed slits (second clearances) 614b for restricting a circumferential magnetic path. Thus, the same effects as above are attained also in this embodiment. Also in this embodiment the ratio [Wmg:Wsp] of the width, Wmg, of each permanent magnet 62b to the width, Wsp, of each interpole 613 both in the rotational direction is set at approximately [5:1]. [0068]
Fig. 15 illustrates a plane shape of a rotor yoke 61c according to the fourth embodiment of the present invention and Fig. 16 is a partial enlarged diagram showing a state in which a permanent magnet 62c is inserted into an opening 611c formed in the rotor yoke 61c. In both figures, the same reference numerals as in the previous description represent the same or equivalent

portions.
[0069]
In this embodiment, each opening 611c formed in the rotor yoke 61c is of a special shape with cutout portions being formed on both sides of a drum-like portion, and a permanent magnet 62c having a drum-shaped section is inserted into the opening 611c. As a result, clearances 612c for preventing the leakage of magnetic flux between adjacent permanent magnets 62c are formed on both sides in the circumferential direction of each permanent magnet 62c and also on the stator side at both ends of each permanent magnet 62c there are formed clearances 614c for restricting a circumferential magnetic path. Thus, the same effects as above are obtained also in this embodiment. Also in this embodiment the ratio [Wmg:Wsp] of the width, Wmg, of each permanent magnet 62c to the width, Wsp, of each interpole 613 both in the rotational direction is set at approximately [5:1] .
[0070]
Fig. 17 illustrates a plane shape of a rotor yoke 61d according to the fifth embodiment of the present invention and Fig. 18 is a partial enlarged diagram showing a state in which a permanent magnet 62d is inserted into an opening 611d formed in the rotor yoke

61d. In both figures, the same reference numerals as in the previous description represent the same or equivalent portions.
[0071]
In this embodiment, each opening 611d formed in the rotor yoke 61d is like a drum of a special shape and a permanent magnet 62d having a drum-shaped section is inserted into the opening 611d. As a result, clearances 612d for preventing the leakage of magnetic flux between adjacent permanent magnets 62d are formed on both sides in the circumferential direction of each permanent magnet 62d.
[0072]
Further, separately from the opening 611d, clearances 614d for restricting a circumferential magnetic path are formed like cutouts in inner peripheral portions of the rotor yoke 61d corresponding to both ends of each permanent magnet 62d. Therefore, the same effects as above are obtained also in this embodiment. Also in this embodiment the ratio [Wmg:Wsp] of the width, Wmg, of each permanent magnet 62d to the width, Wsp, of each interpole 613 both in the rotational direction is set at approximately [5:1].
[0073]

Fig. 19 illustrates a plane shape of a rotor yoke 61e according to the sixth embodiment of the present invention and Fig. 20 is a partial enlarged diagram showing a state in which a permanent magnet 62e is inserted into an opening 611e formed in the rotor yoke 61e. In both figures, the same reference numerals as in the previous description represent the same or equivalent portions. [0074]
In this embodiment, each opening 611e formed in the rotor yoke 61e is like a drum of a special shape and a permanent magnet 62e having a drum-shaped section is inserted into each opening 611e. As a result, clearances 612e for preventing the leakage of magnetic flux between adjacent permanent magnets 62e are formed on both sides in the circumferential direction of each permanent magnet 62e and also on the stator side at both ends of each permanent 62e there are formed clearances 614e for restricting a circumferential magnetic path. Thus, the same effects as above are obtained also in this embodiment. Also in this embodiment the ratio [Wmg:Wsp] of the width, Wmg, of each permanent magnet 62e to the width, Wsp, of each interpole 613 both in the rotational direction is set at approximately [5:1].

[0075] [Effects of the Invention]
According to the present invention, as described hereinabove, in a permanent magnet type rotary electric machine wherein a rotor yoke of an outer rotor has interpoles each located between adjacent permanent magnets, both driving and driven torques can be made compatible with each other effectively. Therefore, it is possible increase the driving torque when the permanent magnet type rotary electric machine is allowed to function as a starter motor without increasing the driven torque when the rotary electric machine is allowed to function as a generator.
[0076]
According to the present invention, as described hereinabove, in a permanent magnet type rotary electric machine wherein a rotor yoke of an outer rotor has interpoles each located between adjacent permanent magnets, the ratio [Wmg:Wsp] of the width, Wmg, of each of the permanent magnets to the width, Wsp, of each of the interpoles both in the rotational direction is optimized and the advance angle of an alternating current to be fed to each phase terminal is optimized on the basis of the width, Wsp, of each interpole in the

rotational direction. Therefore, when the permanent magnet type rotary electric machine is allowed to function as an electric motor, there is attained an improvement of torque particularly in a low rotation region, while when the rotary electric machine is allowed to function as a generator, it is possible to diminish friction in a high rotation region.
[Explanation of Reference Numerals]
1 ... starter/generator, 50 ... stator, 51 ... stator core, 52 ... stator salient pole, 53 ... stator winding, 60 ... outer rotor, 61 ... rotor yoke, 62 (62N, 62S) ... permanent magnet, 63 ... rotor case, 71 ... protective cover, 201 ... crank shaft, 611 ... opening, 612 ... slit (first clearance), 613 . . . interpole, 614 . . . slit (second clearance)

WE CLAIM :
1. A permanent magnet type rotary electric machine wherein a rotor yoke of a generally cylindrical shape adapted to rotate along an outer periphery of a stator is formed with a plurality of magnet inserting holes in a circumferential direction thereof alternately with interpoles, and permanent magnets are inserted into said magnet inserting holes, respectively, characterized in that:
said magnetic inserting holes each comprises a main opening for insertion therein of each of said permanent magnets and slits extending with a predetermined width (W) toward a central portion from both end portions in the circumferential direction of said main opening, and a residual thickness (H) of the rotor yoke at the tip of each said slit and said slit width (W) satisfy the relationship of 0.3 wherein said permanent magnet type rotary electric machine comprises a control unit which feeds an exciting current from a battery to each stator winding at a rotational speed lower than a predetermined rotational speed, and is driven by the internal combustion engine at a rotational speed not lower than a predetermined rotational speed.
2. A permanent magnet type rotary electric machine as claimed in claim 1, wherein the residual thickness (H) /slit width (W) is approximately 0.5.
3. A permanent magnet type rotary electric machine wherein a rotor yoke of a generally cylindrical shape adapted to rotate along an outer periphery of a stator is formed with a plurality of magnet inserting holes in a circumferential direction thereof alternately with interpoles, and permanent magnets are inserted into said magnet inserting holes, respectively, wherein the ratio (Wmg:Wsp) of the width, Wmg, of each said permanent magnet to the width, Wsp, of each said interpole both in a rotational direction is approximately (5:1).

4. A permanent magnet type rotary electric machine as claimed in claim 3, said permanent magnet type rotary electric machine comprises a control unit which feeds an exciting current from a battery to each stator winding at a rotational speed lower than a predetermined rotational speed, and is driven by the internal combustion engine at a rotational speed not lower than a predetermined rotational speed.
5. A drive unit for a permanent magnet type rotary electric machine wherein a rotor yoke of a generally cylindrical shape adapted to rotate along an outer periphery of a stator is formed with a plurality of magnet inserting holes in a circumferential direction thereof alternatively with interpoles, and permanent magnets are inserted into said magnet inserting holes, respectively, wherein
the phase of an alternating current to be fed to each phase terminal of said permanent magnet type rotary electric machine is advanced by an angle corresponding to 1 to 1.5 times the width, Wsp, of each said interpole in a rotational direction.
6. A permanent magnet type rotary electric machine substantially as
hereinbefore described with reference to the accompanying drawings.
Dated this 3rd day of August,2001.

Documents:

746-mum-2001-cancelled pages(3-3-2006).pdf

746-mum-2001-claim(granted)-(3-3-2006).doc

746-mum-2001-claims(granted)-(3-3-2006).pdf

746-mum-2001-correspondence(28-3-2006).pdf

746-mum-2001-correspondence(ipo)-(18-5-2006).pdf

746-mum-2001-drawing(3-8-2001).pdf

746-mum-2001-form 1(3-3-2006).pdf

746-mum-2001-form 1(3-8-2001).pdf

746-mum-2001-form 18(16-6-2005).pdf

746-mum-2001-form 2(granted)-(3-3-2006).doc

746-mum-2001-form 2(granted)-(3-3-2006).pdf

746-mum-2001-form 3(3-3-2006).pdf

746-mum-2001-form 3(3-8-2001).pdf

746-mum-2001-form 5(3-3-2006).pdf

746-mum-2001-form 5(3-8-2001).pdf

746-mum-2001-petition under rule137(3-3-2006).pdf

746-mum-2001-petition under rule138(3-3-2006).pdf

746-mum-2001-power of authority(19-11-2001).pdf

746-mum-2001-power of authority(3-3-2006).pdf

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Patent Number

205062

Indian Patent Application Number

746/MUM/2001

PG Journal Number

25/2007

Publication Date

22-Jun-2007

Grant Date

13-Mar-2007

Date of Filing

03-Aug-2001

Name of Patentee

HONDA GIKEN KOGYO KABUSHIKI KAISHA

Applicant Address

BUSINESS AT 1-1, MINAMIAOYAMA 2-CHOME, MINATO-KU, TOKYO, JAPAN.

Inventors:

#	Inventor's Name	Inventor's Address
1	SHIBATA KAZUMI,	C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, OF 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA, JAPAN.
2	OTA ATSUO	C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, OF 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA, JAPAN.
3	ONOZAWA SEIJI	C/O KABUSHIKI KAISHA HONDA GIJUTSU KENKYUSHO, OF 4-1, CHUO 1-CHOME, WAKO-SHI, SAITAMA, JAPAN.

PCT International Classification Number

H 02 K 21/22

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2000-256014	2000-08-25	Japan
2	2000-343520	2000-11-10	Japan