Title of Invention

ANOUTER ROTOR TYPE BRUSHLESS MOTOR STRUCTURE

Abstract

An outer rotor type brushlee motor structure wherein the motor fixed side being a stator, a rotor on the motor rotary side being provided outside the stator and an angle sensor for detecting a rotor truing angle being provided, Wherein said rotor has a container shape with side opened for accommodating said stator, and wherein a permanent magnet is attached to an inner peripheral surface of a peripheral wall, provided in an outer peripheral part of the rotor, surrounding said stator, further wherein an opened edge of the peripheral wall is partially projected, in correspondence with the permanent magnet, as a detection projection further wherein the permanent magnet, as a detection projection, further wherein a detection portion of said angle sensor as a magnetic sensor is provided in the proximity of the detection projection.

Full Text

FORM 2 THE PATENTS ACT 1970 [39 OF 1970] COMPLETE SPECIFICATION [See Section 10] "OUTER ROTOR TYPE BRUSHLESS MOTOR STRUCTURE" HONDA GIKEN KOGYO KABUSHIKI KAISHA, a corporation of Japan, 1-1, Minamiaoyama 2-chome, Minato-ku, Tokyo, Japan 26 FEB 2002 The following specification particularly describes the nature of the invention and the manner in which it is to be performed :- type brushless motor structure. In this example, a boss 4 of a rotor 3 is coupled to one end of output shaft 2 passing through the center of a stator 1 on the motor fixed side, a sensor magnet 5 is provided on an outer periphery of an end of the boss 4 extending inside the motor, and a magnetic sensor 6 is provided in the proximity of the magnet. Reference numeral 7 denotes a stator coil, and 8, a permanent magnet. [0003] [Problems to Be Solved by the Invention] Note that the above-described magnetic sensor 6 detects a magnetic pole position of the permanent magnet 8 provided in the rotor 3 by a magnetic change upon passing of the sensor magnet 5 previously provided in correspondence with the permanent magnet 8. However, when an electric current is passed through the coil 7 of the stator 1, a magnetic field occurs around the coil, accordingly, if the sensor magnet 5 is provided near it, the magnet might be magnetically influenced by the magnetic field of the coil 7. Accordingly, a structure with reduced such magnetic influence is desired. Further, as the position of the sensor magnet 5 is closer to the rotational center of the motor, the setting range is smaller and the detection accuracy of the sensor cannot be increased. Accordingly, a structure to easily improve the detection accuracy is desired. Further, it is desirable to reduce the cost by omitting the sensor magnet 5 itself. Accordingly, the present invention has an object to realize these requirements. [0004] [Means to Solve the Problems] 3 -To solve the above problems, the invention in claim 1 according to the outer rotor type brushless motor structure of the present application is characterized in that, predicated on a structure where the motor fixed side being a stator, a rotor on the motor rotary side being provided outside the stator, and an angle sensor for detecting a rotor turning angle being provided, said rotor has a container shape with one side opened for accommodating said stator, and a permanent magnet is attached to an inner peripheral surface of a peripheral wall, provided in an outer peripheral part of the rotor, surrounding said stator, further, an opened edge of the peripheral wall is partially projected, in correspondence with the permanent magnet, as a detection projection, and further, a detection portion of said angle sensor as a magnetic sensor is provided in the proximity of the detection projection. [0005] The invention in claim 2 is characterized in that in the above-described structure, said rotor has a container shape with one side opened for accommodating said stator, and a permanent magnet is attached to an inner peripheral surface of a peripheral wall, Provided in an outer peripheral part of the rotor, surrounding said stator, further, an opened edge of the peripheral wall is partially projected, in correspondence with the permanent magnet, as a detection projection, and further, the detection projection passes through a detection portion of said angle sensor as an optical sensor. 4 [0006] The invention in claim 3 is characterized in that in claim 1 or 2, the number of said detection projections is an arbitrary number different from that of said permanent magnets. [0007] The invention in claim 4 is characterized in that the above-described structure, a sensor magnet is provided on an outer peripheral surface of said rotor, and a detection portion of said angle sensor as a magnetic sensor is provided in the proximity of the magnet. [0008] [Effects of the Invention] According to the invention in claim 1, as the peripheral wall of the rotor is partially projected in correspondence with the permanent magnet, as the detection projection, and the detection portion of the magnetic sensor is provided in the proximity of the detection projection, the magnetic flux of the permanent magnet provided in the rotor passes through the detection projection. Accordingly, every time the detection projection passes through, the magnetic sensor detects a magnetic change and detects the position of the permanent magnet in the rotor. [0009] At this time, as the detection projection is positioned on the outer periphery of the rotor and away from the coil of the stator, the influence by the magnetic field caused by the coil is reduced, and the position of the permanent magnet can be accurately detected. Further, as the detection position of 5 the magnetic sensor is on the outer periphery of the rotor, the detection accuracy can be easily improved in comparison with the case where the detection position is on the motor center side. Further, as the permanent magnet is utilized, a specialized sensor magnet can be omitted, and the cost can be reduced. [0010] According to the invention in claim 2, every time the detection projection provided in correspondence with the permanent magnet on the outer periphery of the rotor passes through the detection portion of the optical sensor, it blocks detection light from the detection portion, thus the position of the permanent magnet can be detected. In this case, similar effects to those in claim 1 can be attained. [0011] According to the invention in claim 3, as the number of the detection pro jecti on s is an arbitrary number different from that of the permanent magnets, the detection projection can be utilized as a turning angle sensor such as a pulsar, and the detection result can be utilized for various controls. [0012] According to the invention in claim 4, as the sensor magnet is provided on the outer peripheral surface of the rotor, the magnetic influence by the coil of the stator can be reduced as soon as possible, and as the sensor magnet is provided on the outer periphery of the rotor, the detection accuracy can be improved. [0013] 6 [Working Examples] Hereinbelow, working examples will be described with reference to the drawings. Fig. 1 is an entire cross sectional view of an outer rotor type brushless motor for a vehicle according to a first working example. Note that in the following description, upward/downward leftward/rightward directions and the like are based on illustrated states in the figures. This motor 10 has a stator 11 on the motor fixed side, an output shaft 12 passing through the center thereof, and a rotor 13 fixed to its one end. The rotor 13 is on the motor rotary side, and one end of the output shaft 12 is taper-coupled to a boss 14 provided in the central portion thereof and further coupled integrally rotatably with the output shaft 12 by a key 15 and a shaft-end nut 16. [0014] The rotor 13 has the boss 14 and a flywheel 17 integral with the boss 14 covering the outside of the stator 11. The rotor has a container shape in which the stator 1 can be accommodated, and one side of the rotor is opened as the insertion side of the stator 11. The outer periphery of the flywheel 17 serves as a peripheral wall 18 surrounding the stator 11. A predetermined number of permanent magnets 19 are provided on an inner peripheral surface of the peripheral wall 18 in a circumferential direction, and the magnets are opposite to the outer periphery of the stator 11. [0015] In a portion of the peripheral wall 18 where the permanent magnets 19 are provided, an edge facing the opening as the stator 8 11 insertion side is projected toward the rotational axial direction, as a detection projection 20. Note that other portion of the edge facing the above opening of the peripheral wall 18 than the detection projection 20 is bent in the rotational central direction as a swaging portion 21 to hold the permanent magnets 19. [0016] A magnetic sensor 22 is provided near a projection end of the detection projection 20, and its detection portion 23 is provided in the proximity of an outer surface of the detection projection 20, i.e., a surface on the outside in the rotational radial direction of the rotor, a main body 24 is bent at an approximately right angle from the detection portion 23 and extended inside the rotor rotational radial direction, and a base 25 is attached to the stator 11 near the boss 14 by a bolt 26. The magnetic sensor 22 is a well-known part for detecting a magnetic change and outputting an electrical detection signal to a control device (not shown) . In the present working example, the sensor constructs an angle sensor for grasping the turning angle of the rotor 3 by detecting the position of the permanent magnet 19 via the detection projection 20. [0017] Plural stators 11 are formed radially in correspondence with the permanent magnets 19, and respectively fixed to a support member 27 . The support member 27 is immovably attached to a vehicle body side member 28. A coil 30 is put around each stator 11, and is energized at optimum timing by the control device (not shown) via connectors 31 based on rotor turning 9 angle information detected by the magnetic sensor 20. [0018] Note that a tip of the detection projection 20 is projected rightward in the figure further from the outmost position of the coil 30 in the rotational axial direction. The connectors 31, for electric-current supply for the respective stators 11 and for signal line of the magnetic sensor 20, are attached to the stators 11 by a clip 32 and a bolt 33. [0019] Next, an operation of the present working example will be described. By passing an electric current through the coil 30, the rotor 13 rotates, then, in accordance with the rotation, the detection projection 20 passes through a position near the detection portion 23 of the magnetic sensor 22 . As the magnetic flux of the permanent magnet 19 passes through the detection projection 20, the magnetic sensor 22 detects a magnetic change upon passing of the detection projection 20 and outputs an electric detection signal. [0020] As the position of the permanent magnet 19 in correspondence with the detection projection 20 is grasped by this signal, the turning angle of the rotor 13 can be detected. Further, since the detection projection 20 is provided on the peripheral wall 18 as the outer periphery of the rotor 13 and the detection portion 23 of the magnetic sensor 22 is positioned on the outer periphery of the detection projection 20 and away from the coil 30 of the stator 11, the influence by the magnetic field caused by the coil 30 is reduced, and the position of the permanent magnet 19 can be accurately detected. Further, as the detection projection 20 is projected further rightward in the figure from the outmost side of the coil 30, the magnetic influence is further reduced. [0021] Further, as the detection position of the magnetic sensor 22 is on the outer periphery of the rotor 13, the detection accuracy can be easily improved in comparison with a case where the magnetic sensor 22 is provided on the central side as in the case of the conventional art. Further, as the detection projection 20 is magnetized by utilizing the magnetic flux of the permanent magnet 19, a specialized sensor magnet can be unnecessitated, thus the cost can be reduced. [0022] Note that the number of detection projections 20 may be an arbitrary number different from that of the permanent magnets 19. For example, if the number of detection projections 20 is one, the magnetic sensor 22 detects one magnetic change and generates a detection signal per one rotation of the rotor 13. Accordingly, this can be utilized as a pulsar signal and utilized as various control signals based on the motor rotation. [0023] Further, if plural detection projections 20 are used, as the number increases, the detection accuracy can be increased. Further, if the rotation of the rotor 13 is synchronized with or set in a predetermined ratio with respect to that of engine crankshaft (not shown), the signal can be 11 utilized for engine ignition timing control and fuel injection control. Note that in any case, another sensor is provided in a position corresponding to the permanent magnet 19 for rotation control of the motor itself. [0024] Fig. 2 is a diagram similar to Fig. 1 according to a second working example. This working example differs from the first working example in that an optical angle sensor 42 having a well-known photointerrupter structure is provided in place of the magnetic sensor. A detection portion 43 of the angle sensor 42 has a light emitting portion 47 and a photoreception portion 48. These light emitting portion 47 and the photoreception portion 48 are opposite to each other with a groove 49 therebetween, and the light emitting portion 47 always emits detection light toward the photoreception portion 48. [0025] A tip of the detection projection 20 passes through the groove 49 while it enters the groove. As the tip blocks the detection light upon passing, the photoreception portion 48 temporarily cannot receive the detection light, and the angle sensor 42 detects the passing of the detection projection 20 and generates an electric signal. Thus the sensor detects the position of the permanent magnet 19 corresponding to the detection projection 20, and detects the turning angle of the rotor 13. [0026] Note that the other portions in the angle sensor 42, a main body 44 and a base 45, are similar to those in the magnetic 12 sensor 22. The base 45 is attached to the stator 11 by a bolt 46. Further, as the motor structure except the angle sensor 42 is similar to that of the first working example, corresponding reference numerals are given in the figure and the explanations thereof will be omitted. [0027] In this structure, the angle sensor 42 can be an optical sensor and the magnetic influence by the coil 30 can be fully removed. Further, similar effects, the improvement in detection accuracy by providing the detection projection 20 on the outer periphery of the rotor 13 and the omission of sensor magnet, can be attained. Further, the utilization as the above-described pulsar can be made. [0028] Fig. 3 is a diagram similar to Fig. 1 according to a third working example. This working example differs from the first working example in that the detection projection of the first working example is removed, a step portion 50 is provided on an outer peripheral surface side of a portion of the peripheral wall 18 as a shoulder of the flywheel 17, and a sensor magnet 51 is attached in the step portion 50 such that an outer surface of the magnet is in approximately the same plane as the other outer peripheral surface portion of the peripheral wall 18. Further, a detection portion 53 of the magnetic sensor 52 is provided to be opposite to the sensor magnet 51, and the magnetic sensor 52 is fixed by a screw 55 to a flange 54 on the vehicle body side member 28 positioned outside the rotor 13. [0029] 13 In this arrangement, every time the sensor magnet 51 passes through by the rotation of the rotor 13, the magnetic sensor 52 detects the passing and detects the turning angle of the rotor 13 . Further, as the magnetic sensor 52 is provided further outward in the rotational radial direction from the peripheral wall 18 of the rotor 13, the magnetic sensor 52 is isolated from the coil 30 by the rotor 13. Accordingly, the magnetic influence by the coil 30 to the magnetic sensor 52 can be reduced as soon as possible. Further, the effect of the improvement in detection accuracy by providing the sensor magnet 51 on the outer periphery of the rotor 13 can be attained as in the case of the respective above working examples. [0030] Note that the present invention is not limited to the above-described working examples, but various changes and applications can be made within .the same principle of the invention. For example, the purpose as the outer rotor type brushless motor according to the present invention can be widely utilized for general machines as well as vehicles. 14 We claim: 1. An outer rotor type brushless motor structure wherein the motor fixed side being a stator, a rotor on the motor rotary side being provided outside the stator, and an angle sensor for detecting a rotor turning angle being provided, characterized in that said rotor has a container shape with one side opened for accommodating said stator, and wherein a permanent magnet is attached to an inner peripheral surface of a peripheral wall, provided in an outer peripheral part of the rotor, surrounding said stator, further wherein an opened edge of the peripheral wall is partially projected, in correspondence with the permanent magnet; as a detection projection, further wherein a detection portion of said angle sensor as a magnetic sensor is provided in the proximity of the detection projection. 2. An outer rotor type brushless motor structure wherein the motor fixed side being a stator, a rotor on the motor rotary side being provided outside the stator, and an angle sensor for detecting a rotor turning angle being provided, wherein said rotor has a container shape with one side opened for accommodating said stator, and wherein a permanent magnet is attached to an inner peripheral surface of a peripheral wall, provided in an outer peripheral part of the rotor, surrounding said stator, further wherein an opened edge of the peripheral wall is partially projected, in correspondence with the permanent magnet, as a detection projection, further wherein the detection projection passes through a detection portion of said angle sensor as an optical sensor. 3. The outer rotor type brushless motor structure as claimed in 1 or 2, wherein the number of said detection projections is an arbitrary number different from that of said permanent magnets. 16 4. An outer rotor type brushless motor structure wherein the motor fixed side being a stator, a rotor on the motor rotary side being provided outside the stator, and an angle sensor for detecting a rotor turning angle being provided, wherein a sensor magnet is provided on an outer peripheral surface of said rotor, and wherein a detection portion of said angle sensor as a magnetic sensor is provided in the proximity of the magnet. 5. An outer type brushless motor structure substantially as hereinbefore described with reference to the figures 1 to 3. Dated this 26th day of February, 2002. [RAJAN AILAVABI] OF REMFRY & SAGAR ATTORNEY FOR THE APPLICANTS

Documents:

178-mum-2002-abstract (02-05-2008).doc

178-mum-2002-abstract (02-05-2008).pdf

178-mum-2002-cancelled pages(02-05-2008).pdf

178-mum-2002-claims(granted)-(02-05-2008).doc

178-mum-2002-claims(granted)-(02-05-2008).pdf

178-mum-2002-correspondence(02-05-2008).pdf

178-mum-2002-correspondence(ipo)-(08-05-2007).pdf

178-mum-2002-drawings (26-02-2002).pdf

178-mum-2002-form 1(02-05-2008).pdf

178-mum-2002-form 1(26-02-2002).pdf

178-mum-2002-form 13(02-05-2008).pdf

178-mum-2002-form 18(24-01-2006).pdf

178-mum-2002-form 2(granted)-(02-05-2008).doc

178-mum-2002-form 2(granted)-(02-05-2008).pdf

178-mum-2002-form 3(06-04-2004).pdf

178-mum-2002-form 3(26-02-2002).pdf

178-mum-2002-form 5(26-02-2002).pdf

178-mum-2002-petition under rule 137(02-05-2008).pdf

178-mum-2002-petition under rule 138(02-05-2008).pdf

178-mum-2002-power of attorney(02-05-2008).pdf

178-mum-2002-power of attorney(20-05-2002).pdf

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