Title of Invention

"MOUNTING STRUCTURE OF AN IGNITION COIL DEVICE INTEGRATED WITH PLUG CAP"

Abstract

The invention is intended to provide a structure for mounting an ignition coil device 50 having an integrated plug cap 51 to a spark plug 35 on a cylinder head 34. The ignition coil device 50 is attached via an elastic member 37 to a fan shroud 36 disposed above the cylinder head 34, and is engaged, via the elastic member 37 and near a plug cap, with projections extending 34a from the cylinder head 34. [Advantageous Results] The ignition coil device is engaged with the cylinder head having the spark plug, so that the ignition coil device can be reliably supported even when there is a positional displacement between the spark plug and the ignition coil device. Therefore/ the plug cap of the ignition coil device and the spark plug can be reliably and stably engaged. [Reference Drawing

Full Text

Detailed Description of the Invention] fJ ' [Field of the invention] The present invention relates to a structure for directly mounting an ignition coil device having an integrated plug cap to a spark plug of an engine. [Description of the Related art] Japanese Utility Model Publication No. Sho 62-179364 entitled "Ignition Coil" exemplifies an ignition coil hiving an integrated plug cap. In the following, reference numbers are identical to those shown in the publication. In Fig. 1 of this publication, an ignition coil 10 is constituted by a core 15, surrounding a plug cap 19 to be connected to a spark plug 3 and being coaxial with the spark plug 3, a secondary coil 14 and a primary coil 12, all of which are arranged one after another, and are enclosed by a bottomed cylindrical case 11. The spark plug 3 is screwed into a cylinder head 2, and the ignition coil 10 is fitted into the spark plug 3. The ignition coil 10 is attached to an engine cover 6. [Problems to be solved by the Invention] However, since the engine cover 6 is made of a resin material, there is a time lag between vibrations of the cylinder head 2 and the engine cover 6, and a positional displacement is caused between the spark plug and the ignition coil device. Therefore, an external force will be applied to the spark plug 3. The ignition coil 10 is very heavy because it houses not only the plug cap 19 but also the primary and secondary coils 12, 14, and the core 15. The weight of the ignition coil 10 acts on the spark plug 3, and so it is necessary to pay attention to the mounting strength of the spark coil 3. [Means to solve the Problems] The present invention is intended to overcome the problems of the related art. According to the invention disclosed in claim 1, there is provided a structure for mounting an ignition coil device having an integrated plug cap to a spark plug on a cylinder head. The ignition coil device is attached via an elastic member to a fan shroud disposed above the cylinder head, and is engaged, via the elastic member and near a plug cap, with projections extending from the cylinder head. The ignition coil device is interlocked with the cylinder head having the spark plug. Therefore, even when there is a positional displacement between the spark plug and the ignition coil device, they can be reliably and stably engaged with each other. Accordance to the invention disclosed in claim 2, the projections are integral with forced air cooling fins disposed on the cylinder head. The projections are integrally formed on the cylinder head together with air cooling fins. The projections can be formed without difficulty, and also function as air cooling fins. Further, according to the invention disclosed in claim 3, there is provided a structure for mounting an ignition coil device having an integrated;.plug_cap to a Spark plug on-a cylinder head. The ignition coil device is interlocked with the cylinder head through a fan shroud on the cylinder head. The ignition coil device having an integrated plug cap is attached to the cylinder head having the spark plug. Even when there is a positional displacement between the spark plug and the ignition coil device, the ignition coil device can be reliably held, on the cylinder head. Therefore, the spark plug can be reliably and stably fitted into the plug cap of the ignition coil device. Accordingly, there is provided a mounting structure of an ignition^coil device integrated with a plug cap connected to a spark plug on a cylinder head, said ignition coil device being attached via an elastic member to a fan shroud disposed above the cylinder head, wherein projecting portions extend upward from the cylinder head and characterised in that said ignition coil device is engaged with said projection portions, via the elastic member and near the plug cap. [Brief Description of the Drawings] Fig. 1 is a side view of a scooter type motorcycle to which the mounting structure according to the invention is applied. Fig. 2 is a side view of the engine and the fuel tank. Fig. 3 is a plan view of the engine and the fuel tank. Fig. 4 is a circuit diagram of the ignition coil device. Fig. 5 is a cross section of the ignition coil device, viewed in the direction 5 in Fig. 2. Fig. 6 is a section of the ignition coil device, taken along line 6-6 in Fig. 5. Fig. 7 is a section showing the state in which the ignition coil device is coupled to the engine. Fig. 8 shows a sequence for assembling the ignition coil device. Fig. 9 shows a sequence for attaching the ignition coil device to the engine. Fig. 10 shows the operation of the engine and the fuel tank. Fig. 11 is a section of the modified example of the ignition coil device which is attached to the engine. [Description of Embodiment] The invention will be described with reference to an embodiment shown on the accompanying drawings. In the following, the words "front", "rear", "left" and "right" denote directions from the point of view of a motorcycle rider. Fig. 1 is a side view of a scooter type motorcycle 1 (called the "motorcycle 1"). The motorcycle 1 comprises a chassis 2, a chassis cover 11, a front wheel 21, a rear wheel 22, a rider's seat 25, a fuel tank 26, a power unit 31, a rear cushion 47, and so on. The chassis 2 comprises a head pipe 3, a telescopic fork 4 for mounting the front wheel 21, a down tube 5 extending downward and rearward from the head pipe 3, and a rear frame 6 extending rearward from the end of the down tube 5. The rear frame 6 includes a pair of left and right front sub-frames 6a (only one sub-frame 6a is shown in Fig. 1) extending substantially laterally between the lower end of the down tube 5 and the rear end of the motorcycle 1, a pair of left and right middle sub-frames 6b extending from the rear part of the front sub-frames 6a toward the rear end of the motorcycle 1, and a rear sub-frame 6c joining the ends of the middle sub-frames 6b. The rear frame 6 is substantially The chassis cover 11 includes a front cover 12, a front side cover 13, a leg shield 14, a floor board 15, a rear lower cover 16, a rear upper cover 17, and a rear fender 22. The front cover 12 and the front side cover 13 cover the front part and side of the head pipe 3 and the upper part of the front wheel 21, respectively. The leg shield 14 covers an area in front of the rider's legs, and the floor board 15 receives the rider's feet thereon. The rear lower cover 16 covers the opposite rear sides of the chassis 2. The rear upper cover 17 covers the rear upper part of the chassis 2, and the rear fender 24 covers the upper part of the rear wheels 22. The rider's seat 25 is hinged to the rear upper cover 17, can be opened and closed, and serves to cover an opening at the top of the rear upper cover 17. The fuel tank 26 is attached to the front sub-frame 6a below the leg shield 14. The power unit 31 is a combined unit of a forced air cooling type two-stroke engine 32 and a continuously variable transmission 39. The engine 32 is positioned at the front part of the power unit 31, and the transmission 39 is positioned behind the engine 32. The transmission 39 transmits output of the engine 32 to the rear wheel 22 connected therewith. The motorcycle 1 adopts a swing-arm type rear suspension in which the power unit 31 is suspended from the rear part of the chassis 2 using rear cushions (dampers) 47. Specifically, the power unit 31 is suspended from the middle sub-frames 6b via a link mechanism 41 at the front part and via the rear cushions 47 at the rear part, so that the power unit 31 can rock back and forth (in the running direction of the motorcycle 1). Fig. 2 is a side view showing the positional relationship between the engine 32 and the fuel tank 26. The link mechanism 41 includes a support 42 attached to the middle sub-frames 6b, a pair of links 43 attached to the support 42 in order to be movable back and forth (in the running direction of the motorcycle 1), and a pair of pivots 44 coupled to the movable ends of the links 43. The pivots 44 are movable back and forth, and are formed on a cylinder block (not shown) of the engine 32 as integral members. The engine 32 includes an ignition coil device 50 detachably attached to the front part thereof. The ignition coil device 50 is positioned near a rear end of the fuel tank 26. A lid 27 is positioned at the front part of the rear upper cover 17, and is used for supplying fuel to the fuel tank 26. Fig. 3 is a plan view of the engine 32 and the fuel tank 26, specifically showing that the rear part of the fuel tank 26 is sloped in order to prevent it from interfering with the engine 32. This is because the ignition coil device 50 is positioned close to the fuel tank 26. A cable 72 is connected to the ignition coil device 50 via a coupler 71, and is orientated to the left (i.e. to the lower side of the plane of the drawing sheet of Fig. 3). Therefore, neither the coupler 71 nor the cable 72 come into contact with the rear end 26a of the fuel tank 26. Fuel is supplied to the fuel tank 26 via an orifice 26b. The ignition coil device 50 comprises a secondary coil 54 and a primary coil 56, and has a circuit configuration as shown in Fig. 4. The secondary coil 54 includes a first winding end 54a and a second winding end 54b. The first winding end 54a is connected to the spark plug 35 via a positive terminal 64 for the secondary coil 54, an electric noise preventing resistor 65, a cap terminal 66, and the plug cap 51. The second winding end 54b is grounded via a negative terminal 68 for both the primary and secondary coils 56, 54. The primary coil 56 includes a first winding end 56a and a second winding end 56b. The first winding end 56a is connected to a GDI unit (Capacitance Discharging Ignition unit) 69 via a positive terminal 67 for the primary coil 56. The second winding end 56b is grounded via the negative terminal 68. Fig. 5 is a plan view of the ignition coil device 50, observed in a direction 5 in Fig. 2, specifically showing that no sealant is filled therein. The positive terminal 67 and the negative terminal 68 are juxtaposed on a casing 57 (i.e. on the front side of the plane of the drawing sheet of Fig. 5), and extend into a coupler receptacle 58. The positive terminal 64 and the cap terminal 66 are juxtaposed on a terminal board 53b of a secondary coil bobbin 53. Fig. 6 is a section of the ignition coil device 50, taken along line 6-6 in Fig. 5. In the ignition coil device 50, the plug cap 51 to be engaged with the spark plug 35 (to be described. later) is sequentially covered by a yoke (an iron core) 52, the secondary coil bobbin 53, and a primary coil bobbin 55, all of which are enclosed in the casing 57. The casing 57 is made of an electrically insulating resin material, and includes an annular bottom 57a, an inner cylindrical portion 57b, and an outer cylindrical portion 57c. The casing 57 has an open top. The inner cylindrical portion 57b supports not only the plug cap 51 but also the yoke 52. Specifically, the inner cylindrical portion 57b includes the conductive plug cap 51 on its inner surface as an integral member, and the yoke 52 coaxially embedded therein. The primary coil bobbin 55 having the secondary coil bobbin 53 fitted therein is positioned in a space S defined by the inner and outer cylindrical portions 57b and 57c. In other words, the primary and secondary coil bobbins 55 and 53 made of electrically insulating resin are independent from the casing 57. The secondary coil bobbin 53 includes a cylindrical portion 53a for winding the secondary coil 54 thereon, and a flat terminal board 53b positioned on top of the cylindrical portion 53a. The secondary coil bobbin 53 has an open bottom. The cap terminal 66 is fixedly attached on the terminal board 53b by a projection 53c, and is coupled to an upper end 51a of the plug cap 51. The primary coil bobbin 55 holds the primary coil 56 wound thereon. A sealant 59 made of an electrically insulating resin material is filled in the casing 57 (including the space S defined by the inner and outer cylindrical portions 57b and 57c), via the open top of the casing 57. The coupler receptacle 58 attached to the casing 57 extends substantially parallel to the plane which is orthogonal to the core of the plug cap 51. In Fig. 6, reference number 53d denotes a .member around which the first and second winding ends 54a, 54b of the secondary coil 54 are wound, and 55a denotes a member around which the first and second winding ends 56a, 56b of the primary coil 56 are wound. Fig. 7 is a cross section showing the state in which the ignition coil device is engaged with the engine. Specifically, the ignition coil device 50 is mounted in the fan shroud 36 via the elastic member 37, and is engaged, near the plug cap 51, with the projections 34a protruding from the upper part of the cylinder head 34. The engine 32 is of a forced air cooling type, and is cooled by air streams which are generated by a fan (not shown) in a space defined by the fan shroud 36 (i.e. a forced air cooling cover) covering the cylinder block 33 and the cylinder head 34. The cylinder head 34 receives the spark plug 35 screwed therein, and has two projections 34a in the shape of rods (only one projection 34a is shown in Fig. 7) as integral members. The projections 34a are engaged with the ignition coil device 50 via the elastic member 37, and are integral with the air cooling fins disposed on the cylinder head 34. The elastic member 37 is made of a flexible material such as rubber or the like, and includes a center cylindrical portion 37a and a flat plate 37b extending from the bottom of the center cylindrical portion 37a, which are formed as an integral member. The center cylindrical portion 37 has a pair of cavities 37c (refer to Fig. 6) for elastically receiving the two projections 34a. The cavities 37c are substantially in the shape of a letter T, as shown in Fig. 6, and the projections 34a are identical to the cavities 37c in shape. The fan shroud 36 has a nozzle 36a facing the spark plug 35. The nozzle 36a is elastically supported by the center cylindrical portion 37a of the elastic member 37. The flat plate 37b of the elastic member 37 is in contact with tips of the cooling fins 34b on the cylinder head 34, thereby absorbing vibrations of the fan shroud 36. The ignition coil device 50 is mounted in the elastic member 37 when the center cylindrical portion 37a of the elastic member 37 is fitted into the casing 57. In this state, the plug cap 51 is engaged with the spark plug 35. An elastic sealing member 61 seals the outer surface of the spark plug 35 with which the plug cap 51 is engaged. The ignition coil device 50 is assembled in the following sequence shown in Fig. 8. (1) First of all, the secondary coil 54 and the primary coils 56 are wound around the secondary coil bobbin 53 and the primary coil bobbin 55, respectively. (2) The secondary coil bobbin 53 is fitted into the primary coil bobbin 55 (as shown by an arrow (1)). (3) The primary coil bobbin 55 with the secondary coil bobbin 53 is fitted into the space S defined by the inner and outer cylindrical portions 57b and 57c of the casing 57 (as shown by an arrow ( 2 ) ) . (4) The cap terminal 66 is snap-fitted to the projection 53c of the secondary coil bobbin 53 and the upper end 5 la of the plug cap 51 (as shown by an arrow (3)). (5) The first and second winding ends 54a, 54b, 56a and 56b, and the electric noise preventing resistor 65 are connected to the terminals 64, 66, 67 and 68 (shown in Fig. 4), respectively. (6) Finally, the sealant 59 (shown in Fig. 6) is filled into the casing 57, the inner section is sealed, and the ignition coil device 50 is then in a finished state. The ignition coil device 50 is engaged with the engine 32 in the following sequence shown in Fig. 9. (1) First of all, the spark plug 35 is attached to the cylinder head 34. (2) The elastic member 37 is fitted into the nozzle 36a of the fan shroud 36. (3) The fan shroud 36 is put on the engine 32, and the elastic member 37 is engaged with the cylinder head 34 by tightly fitting the projections 34a into the cavities 37c (as shown by an arrow ( 4 ) ) . (4) The casing 57 is fitted into the center cylindrical portion 37a, so that the ignition coil device 50 is engaged with the elastic member 37 (as shown by an arrow (5)). In this state, the ignition coil device 50 is engaged with the engine 32. Therefore, the plug cap 51 is coupled to the spark plug 35 (as shown by an arrow (6) ) .Assembly is now complete . The sequences shown in Figs. 8 and 9 are described only as an example in order to promote understanding of the foregoing mounting structure . It should be noted that the present invention is not limited to this example. The operation of the ignition coil device 50 will be described with reference to Fig. 4. A low voltage is applied from the GDI unit 69 to the ignition coil device 50 via the positive terminal 67, the primary coil 56, and the negative terminal 68. A high voltage current is then generated in the secondary coil 54, and flows via the plug cap 51, the spark plug 35, and ground. Thereafter, the spark plug 35 sparks and fires the engine 32 (refer to Fig. 7) . The positional relationship between the engine 32 and the fuel tank 26 when the engine 32 rocks will now be described with reference to Fig. 10 (a) to 10(c). When the rear cushions 47 (shown in Fig. 1) are in the middle of the stretching direction, the pivot 44 of the link mechanism 41 is at a relatively high level (as shown in fig. 10(a)), and the ignition coil device 50 is above the rear end 26a of the fuel tank 26. The pivot 44 is below the level shown in Fig. 10(a) when the rear cushions 47 are maximally stretched, as shown in Fig. 10(b). Further, the engine 32 rocks in the counter clockwise direction shown by an arrow in Fig. 10, so that the ignition coil device 50 is near the top of the rear end 26a of the fuel tank 26. When the rear cushions 47 are maximally contracted '(Fig. 10(c)), the pivot 44 is at a level below the level shown in Fig. 10(a). The engine 32 rocks further in the foregoing direction, so that the ignition coil device 50 comes close to the top of the rear end 26a of the fuel tank 26 (i.e. this level is slightly below the level shown in Fig. 10(b). J, The spark plug 35 (refer to Fig. 7) and the ignition coil device 50 are mounted to the engine 32 which is mounted on the chassis 2 via the link mechanism 41 so as to rock back and forth. Therefore, it is possible to reduce a range trough which the spark plug 35 and the ignition coil device 50 may rock. Further, the fuel tank 26 is positioned near the engine 32, which enables effective use of the space in front of these members. Fig. 11 is a section of a modified example of the ignition coil device which is attached to the engine. This modified example features that the ignition coil device 50 passes through the fan shroud 36, and is coupled to the cylinder head 34. In Fig. 11, identical parts have identical numbers to those in Fig. 7. The cylinder head 34 includes two projections 34c (only one projection 34c is shown in Fig. 11) extending along the spark plug 35. The projections 34c are integral with the cylinder head 34. The fan shroud 36 has through-holes 36b at positions corresponding to the tops of the projections 34c. A collar 82 having an elastic piece 81 is fitted into the through-hole 36b. The casing 57 of the ignition coil device 50 includes a bracket 57d as an integral member, into which a bolt inserting collar 83 is fitted. The ignition coil device 50 is coupled to the cylinder head 34 by joining a bolt 84 to the projections 34c using a screw, via the two collars 83 and 82. Specifically, the collar 82 with the elastic piece 81, the bolt inserting collar 83 and the bracket 57d are laid on top of the projections 34c, and are joined to the projections 34c using a bolt 84. Thus, the ignition coil device 50 is coupled to the cylinder head 34. As long as the elastic member 37 can be reliably engaged, the number of projections 34a and the number of cavities 37c are not limited to two. Further, the projections 34a and cavities 37c may be any shape. This also applies to the number of projections 34c and the number of brackets 57d in the modified example. The elastic member 37 may be any shape as long as it is engageable with the projection 34a and the ignition coil device 50. The elastic member 37 is not always required to be fitted in the nozzle 36a of the fan shroud 36. [Effect of the Invention] According to the invention disclosed in claim I, there is provided a structure for mounting an ignition coil device having an integrated plug cap to a spark plug on a cylinder head. The ignition coil device is attached via an elastic member to a fan shroud disposed above the cylinder head, and is engaged, via the elastic member and near a plug cap, with projections extending from the cylinder head. The ignition coil device is interlocked with the cylinder head having the spark plug. Therefore, even when there is a positional displacement between the spark plug and the ignition coil device, they can be reliably and stably engaged with each other. In accordance with the invention disclosed in claim 2, the projections are integral with forced air cooling fins disposed on the cylinder head. The projections are integrally formed on the cylinder head together with air cooling fins. The projections can be formed without difficulty, and also function as air cooling fins. According to the invention disclosed in claim 3, there is provided a structure for mounting an ignition coil device having an integrated plug cap to a spark plug on a cylinder head. The ignition coil device is interlocked with the cylinder head through a fan shroud on the cylinder head. The ignition coil device having an integrated plug cap is attached to the cylinder head having the spark plug. Even when there is a positional displacement between the spark plug and the ignition coil device, the ignition coil device can be reliably held on the cylinder head. Therefore, the spark plug can be reliably and stably fitted into the plug cap of the ignition coil device. [Description of the Numerals] 32 engine 34 cylinder head 34a projections 34b cooling fins 35 spark plug 36 fan shroud (engine cover) 36a nozzle 36b through hole 37 elastic (engaging) member 50 ignition coil device 51 plug cap 52 yoke 53 secondary coil bobbin 54 secondary coil 55 primary coil bobbin 56 primary coil 57 casing 57a annular bottom 57b inner cylindrical portion (for holding yoke) 57c outer cylindrical portion 57d bracket 59 sealant 81 elastic pieces 84 bolt S space defied by inner and outer cylindrical portions WE CLAIM: 1. A mounting structure of an ignition coil device (50) integrated with a plug cap (51) connected to a spark plug (35) on a cylinder head (34), said ignition coil device (50) being attached via an elastic member (37) to a fan shroud (36) disposed above the cylinder head (34), wherein projecting portions extend upward from the cylinder head (34) and characterised in that said ignition coil device (50) is engaged with said projection portions, via the elastic member (37) and near the plug cap (51). 2. A mounting structure as claimed in claim 1, wherein the projections (34a) are integral with forced air cooling fins (34b) disposed on the cylinder head (34). 3. A mounting structure as claimed in claim 1, wherein the ignition coil device (50) is interlocked with the cylinder head (34) through a fan shroud (36) on the cylinder head (34). 4. A mounting structure substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

Documents:

1638-del-1997-abstract.pdf

1638-del-1997-claims.pdf

1638-del-1997-correspondence-others.pdf

1638-del-1997-correspondence-po.pdf

1638-del-1997-description (complete).pdf

1638-del-1997-drawings.pdf

1638-del-1997-form-1.pdf

1638-del-1997-form-13.pdf

1638-del-1997-form-19.pdf

1638-del-1997-form-2.pdf

1638-del-1997-form-3.pdf

1638-del-1997-form-4.pdf

1638-del-1997-form-6.pdf

1638-del-1997-gpa.pdf

1638-del-1997-petition-137.pdf

1638-del-1997-petition-138.pdf

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