JP2013209079A - Electric power unit for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric power unit for a vehicle, which requires small numbers of parts and assembly processes and which is also capable of reducing the weight and securing the stiffness of a transmission case.SOLUTION: A second gear case portion 22 housing a secondary reduction gear train 14 is provided integrally continuous to a rear end of a shaft case portion 21 housing a propeller shaft 11. A first opening portion 23 for inserting the propeller shaft 11 and a drive gear 17 of the secondary reduction gear train 14 and for attaching a first bearing 33 supporting a rear portion of the propeller shaft 11 to the shaft case portion 21 or the second gear case portion 22 is provided in a front end of the shaft case portion 21. In addition, a second opening portion 24 for inserting a driven gear 17 of the secondary reduction gear train 14 and a rear axle holder 48 holding a bearing 47 supporting a rear axle 12 is provided in one side portion of the second gear case portion 22.

Description

  The present invention relates to an electric motor, a propeller shaft arranged in parallel with the rotor shaft of the electric motor, a rear axle arranged at right angles to the propeller shaft and driving a rear wheel of the vehicle, and an output of the rotor shaft A primary reduction gear train that transmits the propeller shaft at a reduced speed to the front portion of the propeller shaft, a secondary reduction gear train that transmits the output of the propeller shaft to the rear axle at a reduced speed from the rear portion, and the electric motor The present invention relates to an improvement in an electric power unit for a vehicle including a propeller shaft, a primary reduction gear train, and a transmission case that houses a secondary reduction gear train.

  Such an electric power unit for a vehicle is already known as disclosed in Patent Documents 1 and 2 below.

JP-A-5-105160 JP-A-5-213253

  In the conventional electric power unit for a vehicle, the transmission case is divided between a shaft case portion that houses the propeller shaft and a gear case portion that houses the secondary reduction gear train, and the gear case portion is further divided into the secondary reduction gear train. The body part of the gear case part is divided into a shaft case part and a cover part that supports the inner end part of the rear axle via a bearing, and an axle holder that supports an intermediate part of the rear axle via a bearing. When connecting the propeller shaft and the drive gear through the joint in the shaft case portion. In such a case, the number of parts and assembly man-hours are large, and it is difficult to reduce the product cost. In addition to the division between the shaft case and the gear case, the gear case is divided into three parts, resulting in a reduction in the rigidity of the transmission case. If the thickness of each part of the transmission case is increased to compensate for this, the weight of the electric power unit will increase.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide the above-described electric power unit for a vehicle that has a small number of parts and an assembling man-hour, and is capable of both reducing the weight of the transmission case and ensuring rigidity. And

  In order to achieve the above object, the present invention drives an electric motor, a propeller shaft arranged in parallel to the rotor shaft of the electric motor, and a vehicle rear wheel arranged at right angles to the propeller shaft. A rear axle, a primary reduction gear train that decelerates and transmits the output of the rotor shaft to the front portion of the propeller shaft, and a secondary reduction gear that decelerates and transmits the output of the propeller shaft from the rear portion to the rear axle. An electric power unit for a vehicle comprising a train and a transmission case that supports the electric motor, and that houses the propeller shaft, a primary reduction gear train, and a secondary reduction gear train. A first gear case portion that supports the motor and accommodates the primary reduction gear train, and a propeller shaft connected to a rear portion of the first gear case portion. And a second gear case portion that is integrally connected to the rear portion of the shaft case portion and accommodates a secondary reduction gear train, while the secondary reduction gear train is configured as the propeller shaft. A drive gear fixed to the rear axle, and a driven gear fixed to the rear axle and meshed with the drive gear. The propeller shaft and the drive gear are provided at the front portion of the shaft case portion. And a first opening for mounting the first bearing for supporting the propeller shaft adjacent to the drive gear to the shaft case portion or the second gear case portion, and the second gear case. One side of the part includes a bearing for inserting the driven gear into the second gear case part and for supporting the rear axle. A second opening for mounting the rear axle holder holding provided, the first characterized in that a one piece integrally molding the shaft case portion and the second gear case portions.

  In addition to the first feature, the present invention has a second feature that a bearing holder that holds a second bearing that supports a front portion of the propeller shaft is attached to the first opening.

  In addition to the second feature of the present invention, the first gear case portion is detachably joined to the front end of the shaft case portion, and the bearing holder is formed integrally with the first gear case portion. Three features.

  Furthermore, according to the present invention, in addition to the first feature, the second bearing for supporting the front portion of the propeller shaft is mounted on the front side wall of the first gear case portion for supporting the electric motor. It is characterized by.

  Furthermore, in addition to any of the first to fourth features, the present invention can separate the first gear case portion into a front case half that supports the electric motor and a rear end of the front case half. And a rear case half joined to the front end of the shaft case portion.

  Furthermore, in addition to the first feature, the present invention has a sixth feature in which the propeller shaft and the drive gear of the secondary reduction gear train are integrally formed into one component.

  Furthermore, in addition to the first feature, the seventh feature of the present invention is that the rear axle and the driven gear of the secondary reduction gear train are integrally formed into one component.

  Furthermore, in addition to any one of the first to seventh features, the present invention provides a drive gear and a driven gear constituting the primary reduction gear train, wherein the transmission case is made of an Al alloy, the propeller shaft is made of steel. An eighth feature is that a spur gear or a helical gear is used to absorb the difference in thermal expansion between the transmission case and the propeller shaft in the longitudinal direction of the drive gear and the driven gear.

  According to the first aspect of the present invention, the transmission case includes a first gear case portion that supports the electric motor and accommodates the primary reduction gear train, and a propeller shaft that is connected to the rear portion of the first gear case portion. And a second gear case portion that is integrally connected to the rear portion of the shaft case portion and accommodates the secondary reduction gear train, while the secondary reduction gear train is fixed to the propeller shaft. And a driven gear that is fixed to the rear axle and meshes with the drive gear. In the front part of the shaft case part, the propeller shaft and the drive gear are inserted into the shaft case part. A first opening for mounting the first bearing for supporting the propeller shaft adjacent to the gear to the shaft case portion or the second gear case portion is provided. One side of the gear case portion is provided with a second opening for inserting a driven gear into the second gear case portion and for mounting a rear axle holder for holding a bearing for supporting the rear axle. Since the gear case portion is integrally molded into one component, the propeller shaft and the drive gear can be integrated, and the shaft case portion and the second gear case portion can be integrated, and the propeller can be opened from the first and second openings. The shaft and secondary reduction gear train can be easily assembled to the transmission case, and the rigidity of the transmission case is enhanced by the integration of the shaft case and the second gear case. Can be reduced in weight. Also, the integration of the shaft case and the second gear case, and the integration of the propeller shaft and the drive gear reduce the number of parts, and in combination with the integral molding of the shaft case and the second gear case, the cost is reduced. be able to.

  According to the second aspect of the present invention, the propeller shaft support is completed within the shaft case portion by mounting the bearing holder for holding the second bearing supporting the front portion of the propeller shaft in the first opening. As a result, not only can the subsequent primary reduction gear train be assembled easily, but also the coaxial accuracy of the first and second bearings can be easily secured.

  According to the third feature of the present invention, since the first gear case portion and the shaft case portion are separated from each other, each shape can be simplified and each molding can be easily performed, and the first gear case portion can be easily formed. And the bearing holder can be integrated to suppress an increase in the number of parts.

  According to the fourth aspect of the present invention, the accuracy of the inter-shaft distance between the rotor shaft and the propeller shaft is improved by mounting the second bearing supporting the front end portion of the propeller shaft on the front side wall of the first gear case portion. The meshing accuracy of the primary reduction gear train can be improved, and the tilt of the driven gear of the primary reduction gear train can be prevented. Further, the support rigidity of the propeller shaft can be increased by maximizing the distance between the first and second bearings that support the propeller shaft.

  According to a fifth aspect of the present invention, the first gear case portion is detachably joined to the front case half supporting the electric motor and the rear end of the front case half so as to be separated from the front end of the shaft case portion. Therefore, when the specification of the electric motor is changed, only the design of the simple front case half needs to be changed in accordance with the change, and the design change of the transmission case is necessary. Therefore, it is possible to respond to changes in the specifications of electric motors at low cost.

  According to the sixth aspect of the present invention, since the propeller shaft and the drive gear of the secondary reduction gear train are integrally formed as one component, the number of parts and assembly man-hours of the electric power unit are reduced, and the cost is reduced. Not only can it be reduced, but also torque capacity can be increased.

  According to the seventh aspect of the present invention, the rear axle and the driven gear of the secondary reduction gear train are integrally formed into one component, thereby reducing the number of parts and assembly man-hours of the electric power unit, thereby reducing the cost. In addition, the torque capacity can be increased.

  According to the eighth aspect of the present invention, even if a thermal expansion difference occurs in the longitudinal direction of the transmission case and the propeller shaft in accordance with the environmental temperature change, the difference is caused by the drive gear and the driven gear constituting the primary reduction gear train. It will be absorbed by a slight shift in the axial direction of the meshing part of the gear, avoiding unnecessary stress on the transmission case and propeller shaft support, and always ensuring smooth power transmission .

1 is a side view of a motorcycle according to a first embodiment of the present invention. The principal part top view of the said motorcycle. FIG. 3 is a front view of the electric power unit in the motorcycle as viewed from the direction of arrow 3 in FIG. 1. Fig. 3 is a bottom view of the motorcycle. FIG. 5 is an enlarged sectional view taken along line 5-5 in FIG. FIG. 6 is an enlarged sectional view taken along line 6-6 in FIG. The perspective view which looked at the swing arm from the upper part. The perspective view which looked at the same swing arm from the lower part. The perspective view which shows the attachment state to the adjacent member of the same swing arm. FIG. 6 is a view corresponding to FIG. 5 showing a second embodiment of the present invention. FIG. 6 is a view corresponding to FIG. 5 showing a third embodiment of the present invention. FIG. 6 is a view corresponding to FIG. 5 showing a fourth embodiment of the present invention. FIG. 6 is a view corresponding to FIG. 5 showing a fifth embodiment of the present invention. FIG. 6 is a view corresponding to FIG. 5 showing a sixth embodiment of the present invention. The principal part side view of the motorcycle which shows 7th Embodiment of this invention. FIG. 9 is a view corresponding to FIG. 5 showing an eighth embodiment of the present invention. The principal part side view of the motorcycle which shows the same 8th Embodiment. The principal part side view of the motorcycle which shows 9th Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  First, the description starts with the description of the first embodiment of the present invention shown in FIGS. 1 to 4, a scooter type motorcycle V as a vehicle includes a body frame 1, a front fork 2 that is steerably connected to a head pipe 1 a at the front end of the body frame 1 and supports a front wheel 3, An electric power unit P is attached to the rear lower part of the vehicle body frame 1 via a pivot 57 so as to be swingable up and down and supports the rear wheel 4 and drives it, and between the electric power unit P and the vehicle body frame 1, A cushion unit 5 that cushions the vertical swing of the electric power unit P is interposed.

  As shown in FIG. 5, the electric power unit P includes an electric motor 10 arranged with the rotor shaft 10 a directed in the front-rear direction of the motorcycle V, and a propeller shaft arranged in parallel with the rotor shaft 10 a of the electric motor 10. 11, a rear axle 12 disposed at right angles and horizontally with respect to the propeller shaft 11, a primary reduction gear train 13 for reducing the output of the rotor shaft 10 a and transmitting it to the propeller shaft 11, and the output of the propeller shaft 11. A secondary reduction gear train 14 that decelerates and transmits to the rear axle 12, and a transmission case 19 that supports the electric motor 10 and accommodates the primary reduction gear train 13, the propeller shaft 11, and the secondary reduction gear train 14. ing.

  The primary reduction gear train 13 includes a spar drive gear 15 fixed to the rear end portion of the rotor shaft 10a and a spar driven gear 16 fixed to the front end portion of the propeller shaft 11 so as to mesh with the spar drive gear 15. Composed.

  The secondary reduction gear train 14 includes a bevel drive gear 17 formed integrally with the rear end portion of the propeller shaft 11 and a bevel driven gear 18 formed integrally with the rear axle 12 so as to mesh with the bevel drive gear 17. Composed. The propeller shaft 11 and the bevel drive gear 17 are formed into one part by forging, and the rear axle 12 and the bevel driven gear 18 are also formed by forging.

  The transmission case 19 includes a first gear case portion 20 that accommodates the primary reduction gear train 13, a shaft case portion 21 that is coupled to the rear portion of the first gear case portion 20 and accommodates the propeller shaft 11, and the shaft. The second gear case portion 22 is integrally connected to the rear end of the case portion 21 and accommodates the secondary reduction gear train 14. The front end surface of the shaft case portion 21 is formed in the first gear case portion 20. A first opening 23 that opens toward the rear wheel 4 is provided, and a second opening 24 that opens toward the rear wheel 4 is provided on one side surface of the second gear case portion 22.

  The first gear case portion 20 includes a lid-like front case half 25 that supports the electric motor 10 and a rear case half 26 that is detachably joined to the rear end surface of the front case half 25. . Thereafter, the case half body 26 is formed in a box shape from a peripheral wall 26a surrounding the primary reduction gear train 13 and a rear side wall 26b integrally connecting the rear end portion of the peripheral wall 26a to the front end portion of the shaft case portion 21, The front case half 25 is coupled to the front end of the peripheral wall 26 a by a bolt 27. The stator 10 b of the electric motor 10 is fixed to the front end surface of the front case half 25 with bolts 28. At that time, the first gear case portion 20 projects from the shaft case portion 21 to the front side of the rear wheel 4 so that the rotor shaft 10a of the electric motor 10 is as close as possible to the vertical plane A including the rotation center plane of the rear wheel 4. Are arranged as follows.

  The shaft case portion 21 and the second gear case portion 22 are integrally formed by die casting using an Al alloy as a raw material to form one part. At this time, the rear case half 26 is preferably integrally formed with the shaft case portion 21 and the like.

  An annular forward shoulder 30, a first bearing housing 31, and a screw hole 32 are formed at the rear end of the shaft case portion 21 from the rear side. The rear end of the propeller shaft 11 is formed in the first bearing housing 31. The outer race 33a of the first ball bearing 33 for supporting the outer race 33 is fitted, and a ring nut 34 for screwing the outer race 33a to the forward shoulder 30 is screwed into the screw hole 32. A first shim 35 is interposed between the inner race 33 b of the first ball bearing 33 and the bevel drive gear 17, and the bevel drive gear 17 is connected to the inner race 33 b through the first shim 35. A coil spring 36 for pressing and holding with a set load is contracted between the front end surface of the inner race 33b and an annular retainer 37 locked to the propeller shaft 11 via a circlip 42 in front of the inner spring 33b. Is done.

  The propeller shaft 11 with the bevel drive gear 17, the first ball bearing 33, the ring nut 34, the first shim 35, and the coil spring 36 are inserted into the shaft case portion 21 through the first opening 23. In order to make the insertion possible, the outer diameter of the first ball bearing 33 is smaller than the inner diameter of the first opening 23, and the maximum outer diameter of the bevel drive gear 17 is forward facing the outer race 33 a of the first ball bearing 33. It is set smaller than the inner diameter of the shoulder 30.

  A bearing holder 39 that holds a second ball bearing 38 that supports the front portion of the propeller shaft 11 is fitted into the first opening 23 via a seal member 40, and a first mounting flange 39 a of the bearing holder 39 is fitted. Is fastened to the rear side wall 26b of the first gear case portion 20 by bolts 41. The spar driven gear 16 of the primary reduction gear train 13 is attached to the front end portion of the propeller shaft 11 protruding forward of the bearing holder 39. It is desirable that the first and second ball bearings 33 and 38 are sealed so that the inside of the first and second gear case portions 20 and 22 is oil-tight.

  On the other hand, a second bearing housing 45 is formed on the inner wall of the second gear case portion 22, and a ball bearing 46 that supports the inner end portion of the rear axle 12 is fitted thereto. The rear axle 12 with the ball bearing 46 and the bevel driven gear 18 is inserted into the second gear case portion 22 through the second opening 24. In order to enable the insertion, the maximum outer diameter of the bevel driven gear 18 is set smaller than the inner diameter of the second opening 24.

  One end portion of a rear axle holder 48 that holds a pair of ball bearings 47 and 47 that support the rear axle 12 is fitted into the second opening 24 via a seal member 49, and a second attachment of the rear axle holder 48 is performed. A flange 48 a is fastened to the end face of the second gear case portion 22 around the second opening 24 by a bolt 50.

  The rear axle holder 48 is provided with an annular inward shoulder 48b that contacts the outer end of the outer race 47a outside the pair of ball bearings 47, 47. On the other hand, the portion of the rear axle 12 that protrudes outside the second gear case portion 22 is a large-diameter shaft portion 12a from the bevel-driven gear 18 side, and a small-diameter shaft portion 12c that continues to the outer end of the large-diameter shaft portion 12a via a step portion 12b. And a spline shaft portion 12d having a diameter substantially the same as that connected to the outer end of the small diameter shaft portion 12c, and a screw shaft portion 12e having a smaller diameter connected to the outer end of the spline shaft portion 12d. The outer periphery of the shaft portion 12a is in close contact with the seal member 49, and the inner race 47b of each of the pair of ball bearings 47, 47 is fitted to the small diameter shaft portion 12c, and the inner race of the step portion 12b and the inner ball bearing 47 is fitted. A second shim 51 is interposed between the first and second shims 47b. Further, the hub 4a of the rear wheel 4 is spline fitted to the spline shaft portion 12d, and the hub 4a is pressed and held on the stepped portion 12b together with the inner races 47b and the second shims 51 of the pair of ball bearings 47, 47. The nut 52 is screwed onto the screw shaft portion 12e.

  A third shim 53 is fitted between the inner race of the ball bearing 46 that supports the inner end of the rear axle 12 and the step 12f of the rear axle 12 adjacent thereto. The thicknesses of the first, second, and third shims 35, 51, and 53 are selected in advance so that the backlash between the meshing bevel drive gear 17 and the bevel driven gear 18 is appropriate.

  The rear wheel 4 is provided with a brake drum 54 that connects the spoke 4b and the hub 4a. A brake panel 55 that faces the opening of the brake drum 54 is formed integrally with the rear axle holder 48. A brake shoe (not shown) for applying a braking force by friction to the inner peripheral surface of the brake drum 54 is attached to 55.

  1, 4, and 6 to 9, the rear case half 26 of the first gear case portion 20 is integrally formed with an arm attachment portion 63 that protrudes from the lower surface thereof. The rear end portion of the swing arm 56 extending forward and facing the lower surface of the electric motor 10 is detachably fixed. The front end portion of the swing arm 56 extends along the vehicle width direction at the center lower portion of the body frame 1. Is pivotally supported by a pivot 57 attached thereto.

  The swing arm 56 and its peripheral structure will be described in detail with reference to FIGS. 6 to 9. First, the arm mounting portion 63 has a positioning hole 64 extending in the vehicle width direction and a parallel to the positioning hole 64. A plurality of screw holes 65, 65 arranged around the periphery are provided.

  On the other hand, the swing arm 56 has a pair of left and right pivot boss portions 66, 66, a cross member portion 67 that integrally connects the rear portions of the pivot boss portions 66, 66, and a rearward projecting from the cross member portion 67. A pair of left and right arm portions 68, 68. One arm portion 68 is arranged in the vicinity of the pivot boss portions 66, 66 on the same side, and the other arm portion 68 is a cross member 67. Arranged at the intermediate portion, both arm portions 68, 68 are adapted to receive the arm attachment portion 63 therebetween. Both arm portions 68 and 68 are provided with a positioning hole 64 ′ arranged coaxially with the positioning hole 64 and a plurality of bolt holes 65 ′ and 65 ′ corresponding to the plurality of screw holes 65 and 65. The arm portions 68 and 68 are attached to the arm mounting portions by press-fitting the knock pins 69 into the corresponding positioning holes 64 and 64 'and screwing and tightening the bolts 70 inserted into the respective bolt holes 65' into the corresponding screw holes 65. It is fixed to 63.

  The left and right pivot boss portions 66 and 66 are respectively fitted with bearing collars 73 with rubber bushes 72, and the pivots 57 are fitted into the bearing collars 73. Thus, the swing arm 56 is supported by the pivot 57 so as to be able to swing up and down and to be buffered.

  The swing arm 56 is formed with a reinforcing rib 74 that extends horizontally between the arm portions 68 and 68 and the cross member portion 67 and faces the lower surface of the electric motor 10. Further, a pair of left and right stand boss portions 75 and 75 projecting from the lower surface of the swing arm 56 are formed in the vicinity of the left and right pivot boss portions 66 and 66, and a stand 58 is connected to the stand boss portions 75 and 75 via a support shaft 76. And can be stowed and stored. The swing arm 56 is integrally formed by casting in the illustrated example, but may be made of a steel plate.

  Referring again to FIG. 1, a cushion bracket 59 is integrally projected on the upper surface of the second gear case portion 22, and the lower end portion of the cushion unit 5 having the rear end portion connected to the rear portion of the vehicle body frame 1 is connected to the cushion bracket 59. The cushion unit 5 is designed to cushion the electric power unit P from swinging up and down.

  Thus, when the electric power unit P is mounted on the motorcycle V, as shown in FIGS. 2 to 4, the electric motor 10 and the first gear case portion 20 are disposed in front of the rear wheel 4 with the shaft case portion 21 and The second gear case portion 22 is disposed on one side of the rear wheel 4. The axis r of the rotor shaft 10 a of the electric motor 10 is offset from the axis p of the propeller shaft 11 obliquely upward toward the rotation center plane A of the rear wheel 4. Therefore, the axis r of the rotor shaft 10a is offset by a distance a toward the rotation center plane A of the rear wheel 4 with respect to the axis p of the propeller shaft 11, and is offset by a distance b above the axis p of the propeller shaft 11. It will be.

  Next, the operation of the first embodiment will be described.

  When the electric motor 10 is operated in the electric power unit P, the output of the rotor shaft 10a is decelerated by the primary reduction gear train 13 and transmitted to the propeller shaft 11, and then decelerated again via the secondary reduction gear train 14. Thus, the rear wheel 4 is driven and the motorcycle V can be driven.

  In this electric power unit P, the transmission case 19 is connected to the first gear case portion 20 that supports the electric motor 10 and accommodates the primary reduction gear train 13 and the rear side wall of the first gear case portion 20 to be connected to the propeller shaft. 11 and a second gear case portion 22 that is integrally connected to the rear portion of the shaft case portion 21 and accommodates the secondary reduction gear train 14, while the secondary reduction gear train 14 Is composed of a bevel drive gear 17 fixed to the rear end of the propeller shaft 11 and a bevel driven gear 18 fixed to the rear axle 12 and meshing with the bevel drive gear 17. In order to insert the propeller shaft 11 and the bevel drive gear 17 into the shaft case portion 21 and the rear portion of the propeller shaft 11 A first opening 23 for mounting the supporting first bow bearing 33 to the shaft case portion 21 is provided, and a bevel driven gear 18 is inserted into the second gear case portion 22 at one side portion of the second gear case portion 22. For mounting the ball bearing 46 for supporting the inner end of the rear axle on the second gear case portion 22 and for mounting the rear axle holder 48 for holding the ball bearings 47, 47 for supporting the intermediate portion of the rear axle 12. By providing the second opening 24, the first and second openings 23 can be integrated while allowing the propeller shaft 11 and the bevel drive gear 17 to be integrated and the shaft case 21 and the second gear case 22 to be integrated. 24, the propeller shaft 11 and the secondary reduction gear train 14 are easily assembled to the transmission case 19. Bets can be, moreover enhance the rigidity of the transmission case 19 by integration of the shaft case portion 21 and the second gear case portion 22, thinning of the transmission case 19, and by extension becomes possible its weight. Further, the integration of the shaft case portion 21 and the second gear case portion 22 and the integration of the propeller shaft 11 and the bevel drive gear 17 reduce the number of parts, and the shaft case portion 21 and the second gear case portion 22 are integrally formed by casting. In combination, cost can be reduced.

  In addition, the bearing holder 39 that holds the second ball bearing 38 that supports the front portion of the propeller shaft 11 is mounted in the first opening portion 23, thereby completing the support of the propeller shaft 11 within the shaft case portion 21. Thus, the subsequent primary reduction gear train 13 can be easily assembled, and the coaxial accuracy of the first and second ball bearings 33 and 38 can be easily secured.

  Further, the rear case includes a first side wall 26b connected to the front end of the shaft case 21 and a peripheral wall 26a integrally connected to the periphery of the rear side wall 26b and surrounding the primary reduction gear train 13. Since the half body 26 and the front case half body 25 that is separably joined to the front end of the peripheral wall 26a and supports the electric motor 10 are configured, when the specification of the electric motor 10 is changed, a simple shape is adapted to the change. Only the front case half 25 needs to be changed in design, and there is no need to change the design of the transmission case 19 significantly, so that the specification change of the electric motor 10 can be handled at low cost. At this time, if the rear case half 26 is integrally formed with the shaft case portion 21, the dividing surface of the transmission case 19 can be reduced, and the rigidity of the transmission case 19 can be enhanced and the number of parts can be reduced.

  The first gear case portion 20 is disposed so as to protrude from the shaft case portion 21 to the front side of the rear wheel 4, and the rotor shaft 10 a of the electric motor 10 is placed on the vertical plane A including the rotation center plane of the rear wheel 4 as much as possible. Since the electric motor 10 which is a heavy object is located almost immediately before the rear wheel 4 and approaches the pivot 57 that supports the swing arm 56 on the vehicle body frame 1, this improves the running stability of the vehicle. At the same time, the moment of inertia of the electric power unit P including the rear wheel 4 around the pivot 57 can be suppressed as much as possible, and the load on the rear cushion unit 5 can be reduced.

  In addition, the propeller shaft 11 and the bevel drive gear 17 are integrally formed by forging or the like, and the rear axle 12 and the bevel driven gear 18 are integrally formed by forging or the like, and are thus one part. Not only can the number of parts and the number of assembly steps be reduced, the cost can be reduced, but also the torque capacity can be increased.

  Further, the transmission case 19 is made of an Al alloy, the propeller shaft 11 is made of steel, and the primary reduction gear train 13 is composed of a spar drive gear 15 and a spar driven gear 16, so that the transmission case 19 and Even if a thermal expansion difference occurs in the longitudinal direction of the propeller shaft 11, the difference is absorbed by a slight shift in the axial direction of the meshing portion of the spar drive gear 15 and the spar driven gear 16. By avoiding unnecessary stress from being generated in the support portion of the shaft 11, it is possible to always ensure smooth power transmission.

  By the way, the rear end portion of the swing arm 56 extending forward from the lower portion and facing the lower surface of the electric motor 10 is fixed to the transmission case 19, and the front end portion of the swing arm 56 is fixed to the vehicle body via the pivot 57. Since it is pivotally connected to the frame 1, when it is required to increase or decrease the wheel base or to change the position of the electric motor 10 due to changes in the specifications of the applicable vehicle, the pivot arm 56 can be pivoted only by changing the length and shape of the swing arm 56. The distance between the shaft 57 and the rear axle 12, and therefore the wheel base L can be increased or decreased, or the position of the electric motor 10 can be changed. Therefore, it is not necessary to change the transmission case 19 and the transmission member in the transmission case 19, and the new electric power unit P can be provided at a relatively low cost. Even when the capacity of the electric motor 10 is changed, it is not necessary to change the transmission case 19 and the transmission member inside thereof.

  At this time, the swing arm 56 is fixed to the lower portion of the first gear case portion 20 located at the foremost portion in the transmission case 19, thereby shortening the length of the swing arm 56 as much as possible and reducing the weight of the electric power unit P. Can be achieved.

  Furthermore, an arm attachment portion 63 is formed in the lower part of the transmission case 19 and the rear end portion of the swing arm 56 is detachably connected to the arm attachment portion 63, so that the swing arm 56 can be reduced in length when changing the specifications. It is sufficient to replace the one with a different shape, and the new electric power unit P can be provided at a lower cost.

  In addition, the swing arm 56 extends forward from the lower portion of the transmission case 19 and faces the lower surface of the electric motor 10, so that the electric motor 10 can be protected from road surface protrusions and stepping stones. That is, it can serve as a protective member for the electric motor 10.

  In particular, the swing arm 56 includes a pair of left and right pivot boss portions 66 and 66 supported by the pivot 57, a cross member portion 67 that integrally connects the rear portions of the pivot boss portions 66 and 66, and the cross member portion 67. And a pair of left and right arm portions 68 and 68 fixed to the transmission case 19 and extending horizontally between the arm portions 68 and 68 and the cross member portion 67. By forming the reinforcing ribs 74 that oppose each other, the rigidity and weight of the swing arm 56 can be reduced, and the area where the swing arm 56 faces the lower surface of the electric motor 10 can be widened to effectively protect the electric motor 10. Can do.

  Further, the axis r of the rotor shaft 10a of the electric motor 10 is set to the rotation center plane A of the rear wheel 4 with respect to the axis p of the propeller shaft 11 arranged along the front-rear direction of the motorcycle V on one side of the rear wheel 4. By being offset to the side, the center of gravity of the electric power unit P can be brought as close as possible to the rotation center plane A of the rear wheel 4, and the running stability of the motorcycle V can be achieved. Further, by offsetting the axis r of the rotor shaft 10a of the electric motor 10 upward with respect to the axis p of the propeller shaft 11, the ground height h of the electric motor 10 can be sufficiently secured, and muddy water scattered from the road surface, It becomes difficult for earth and sand to be applied to the electric motor 10.

  Next, a second embodiment of the present invention shown in FIG. 10 will be described.

  In the second embodiment, the front case half 25 constituting the first gear case portion 20 is constituted by a peripheral wall 25a and a front side wall 25b integrally formed at the front end thereof. The lid-like rear case half 26 is integrally connected to the shaft case portion 21 and is separably fixed to the rear end of the peripheral wall 25a with a bolt 27. Other configurations are the same as those in the first embodiment, and in FIG. 10, portions corresponding to the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  Next, a third embodiment of the present invention shown in FIG. 11 will be described.

  In the third embodiment, the lid-like rear case half 26 of the first gear case portion 20 is joined to the front end surface of the shaft case portion 21 with a bolt 41, and then the bearing holder 39 is integrated with the case half 26. Since the other configuration is the same as that of the second embodiment, parts corresponding to those of the second embodiment are denoted by the same reference numerals in FIG.

  According to the third embodiment, since the first gear case portion 20 and the shaft case portion 21 are separated from each other, the respective shapes can be simplified and the respective molding can be easily performed, and the first gear case portion. The increase in the number of parts can be suppressed by integrating the bearing 20 with the bearing holder 39.

  Next, a fourth embodiment of the present invention shown in FIG. 12 will be described.

  In the fourth embodiment, a second housing 38 that supports the front end portion of the propeller shaft 11 is attached to the bearing housing 60 formed in the lid-like front case half 25 of the first gear case portion 20, and the shaft case portion 21 is attached. The first opening portion 23 is provided with a seal member 62 for preventing unnecessary transfer of the lubricating oil from the first gear case portion 20 to the shaft case portion 21. Other configurations are the same as those of the first embodiment. Since these are the same, in FIG. 12, the same reference numerals are assigned to the portions corresponding to the first embodiment, and the overlapping description is omitted.

  According to the fourth embodiment, the accuracy of the distance between the rotor shaft 10a and the propeller shaft 11 is improved, the meshing accuracy of the primary reduction gear train 13 can be improved, and the primary reduction gear train 13 The support of the spar-drive gear 16 becomes a double-supported type, and the inclination can be prevented. Furthermore, the distance between the first and second ball bearings 33 and 38 that support the propeller shaft 11 can be maximized to increase the support rigidity of the propeller shaft 11.

  Next, a fifth embodiment of the present invention shown in FIG. 13 will be described.

  In the fifth embodiment, a centrifugal clutch 78 is connected between the rotor shaft 10a of the electric motor 10 and the spar drive gear 15 of the primary reduction gear train 13 in accordance with an increase in the rotational speed of the rotor shaft 10a. The point where it was interposed, the second ball bearing 38 that supports the front portion of the propeller shaft 11, and the seal member 79 adjacent thereto were directly attached to the first opening 23 of the shaft case portion 21, A thrust bearing 81 for receiving a thrust load received from the secondary reduction gear train 14 is interposed between the front case half 25 and the front end portion of the propeller shaft 11, and a bevel drive gear 17 of the secondary reduction gear train 14. A first ball bearing 33 that projects the rear end portion of the propeller shaft 11 from the rear end surface and supports the rear end portion is attached to the second gear case portion 22. The configuration is substantially the same as that of the first embodiment except that it is mounted on the bearing housing 80 that is formed and opens forward. In FIG. 13, parts corresponding to those of the first embodiment are denoted by the same reference numerals. A duplicate description will be omitted. Also in the fifth embodiment, the first ball bearing 33 that supports the rear end portion of the propeller shaft 11 is attached to the bearing housing 80 through the first opening 23 of the shaft case portion 21.

  Next, a sixth embodiment of the present invention shown in FIG. 14 will be described.

  In the sixth embodiment, in order to make the first gear case portion 20 oil-tight, an oil seal 83 that is adjacent to the rear side of the second ball bearing 38 and has a seal lip in close contact with the outer peripheral surface of the propeller shaft 11 is provided as a bearing holder. 39, and in order to fix the inner race 33b of the first ball bearing 33, the inner race 33b together with the first shim 35 and the front end surface of the bevel drive gear 17 are used instead of the coil spring 36 of the first embodiment. A nut 84 that is pressed onto the propeller shaft 11 is screwed onto the propeller shaft 11, and further, an O-ring 85 that is in close contact with the inner peripheral surface of the rear portion of the shaft case portion 21 and an outer peripheral surface of the propeller shaft 11, An oil seal 86 that closely contacts the seal lip is attached to the ring nut 34.

  In the above, the ring nut 34 is a male screw portion 34a that is screwed into the female screw 21a of the shaft case portion 21 and a male screw that is connected to the rear end of the male screw portion 34a and presses the outer race 33a of the first ball bearing 33. The presser tube portion 34b having a smaller diameter than the portion 34a and a flange portion 34c having a diameter larger than that of the male screw portion 34a are connected to the front end of the male screw portion 34a. The O-ring 85 is formed in the outer circumferential groove of the flange portion 34c. Is installed. An annular protrusion 34d that can push the front end of the oil seal 86 is formed on the inner periphery of the ring nut 34, and the annular protrusion 34d screws the ring nut 34 fitted with the oil seal 86 into the screw hole 32. At this time, the oil seal 86 is pressed from the front to set the propeller shaft 11 onto the later-described seal portion 11c.

  The propeller shaft 11 has a bearing fitting portion 11a into which the inner race 33b of the first ball bearing 33 is fitted, a male screw portion 11b into which the nut 84 is screwed, and a seal portion in which a seal lip of the oil seal 86 is in close contact. 11c and a long shaft portion 11d extending forward from the seal portion 11c are formed so as to be successively reduced in diameter, and a tapered guide step portion 11e is provided between the seal portion 11c and the long shaft portion 11d. Accordingly, since the long shaft portion 11d has a smaller diameter than the inner diameter of the oil seal 86, when the oil seal 86 attached to the ring nut 34 is set on the seal portion 11c from the front end of the long shaft portion 11d, the oil seal 86 It is possible to prevent the seal lip from being damaged by the long shaft portion 11d. In addition, when the oil seal 86 is attached to the seal portion 11c, the seal lip is gradually expanded by the tapered guide step portion 11e, so that the seal portion is not damaged. 11c can be easily mounted.

  Further, the inner peripheral surface of the shaft case portion 21 is fitted with the screw hole 32 into which the male screw portion 34a of the ring nut 34 is screwed and the flange portion 34c of the ring nut 34, and the seal portion 21a with which the O-ring 85 is in close contact. , And the hollow portion 21b to which the casting gradient is given is formed so as to increase in diameter sequentially, and a tapered guide step portion 21c is provided between the seal portion 21a and the hollow portion 21b. Therefore, when the male screw portion 34a of the ring nut 34 is screwed into the screw hole 32 of the shaft case portion 21, the male screw portion 34a is smoothly screwed into the screw hole 32 without interfering with the hollow portion 21b and the seal portion 21a. Can be combined. Also, the O-ring 85 can be guided to the tapered step portion 21c to reach the seal portion 21a easily and accurately, and damage to the O-ring 85 can be prevented.

  Thus, by using the bearing holder 39, the ring nut 34, the oil seals 83, 86, etc., the lubricating oil is prevented from flowing into the shaft case portion 21 from the first and second gear case portions 20, 22, and the shaft case. By making the inside of the portion 21 dry, it is possible to keep the lubricating oil stored only in the first and second gear case portions 20 and 22 and to minimize the amount of lubricating oil used in the transmission case 19, and to The oil level fluctuation of the lubricating oil in the first and second gear case portions 20 and 22 can be reduced during acceleration, deceleration, climbing, and downhill.

  The other configurations are the same as those in the first embodiment, and in FIG. 14, portions corresponding to the first embodiment are denoted by the same reference numerals and redundant description is omitted.

  Next, a seventh embodiment of the present invention shown in FIG. 15 will be described.

  In the seventh embodiment, contrary to the first embodiment shown in FIGS. 1 and 5, the front case half 25 of the first gear case portion 20 is formed in a box shape, and then the case half 26 is formed in a lid shape. The swing arm 56 is integrally formed by casting on the front case half body 25, and other configurations are the same as those of the first embodiment. In FIG. The same reference numerals are assigned and duplicate descriptions are omitted.

  According to the seventh embodiment, the box-shaped and highly rigid front case portion 26 and the swing arm 56 are integrated to simplify the structure and increase the connection strength between the swing arm 56 and the front case portion 26. Further, since the front case half 25 with the swing arm 56 separated from the rear case half 26 is a relatively small part, the front case with the swing arm 56 can be changed according to changes in the length and shape of the swing arm 56. Even when a change is made to the mold for forming the half body 25, the change cost is relatively low, which can contribute to the cost reduction of the new electric power unit P.

  Next, an eighth embodiment of the present invention shown in FIGS. 16 and 17 will be described.

  In the eighth embodiment, the front case half 25 of the first gear case portion 20 is formed in a lid shape and the rear case half body 26 is formed in a box shape, and then the case half body 26 is formed on the front end surface of the shaft case portion 21. In this case, the bearing holder 39 and the swing arm 56 are integrally formed by casting in the case half 26 so as to be separable by the bolt 41, and other configurations are the same as those in the first embodiment. In FIG. 16 and FIG. 17, parts corresponding to those of the first embodiment are denoted by the same reference numerals, and redundant description is omitted.

  Also in the eighth embodiment, the box-shaped and highly rigid rear case half 26 and the swing arm 56 are integrated to simplify the structure and increase the connection strength between the swing arm 56 and the rear case half 26. Since the rear case half 26 with the swing arm 56 separated from the shaft case portion 21 is a relatively small part, the rear case with the swing arm 56 can be changed according to changes in the length and shape of the swing arm 56. Even when a change is made to the mold for forming the half body 26, the change cost can be relatively low, which can contribute to the cost reduction of the new electric power unit P.

  Finally, a ninth embodiment of the present invention shown in FIG. 18 will be described.

  In the ninth embodiment, a swing arm 56 is integrally formed by casting on the lid-like front case half 25 of the first gear case portion 20, and the other configuration is the same as that of the eighth embodiment of FIG. In FIG. 18, parts corresponding to those in the eighth embodiment are designated by the same reference numerals, and redundant description is omitted.

  According to the ninth embodiment, the front case half body 25 having a lid shape and having the swing arm 56 becomes a smaller part, so that the rear case having the swing arm 56 according to the change in the length and shape of the swing arm 56. Even when a change is made to the mold for forming the half body 26, the cost of the change becomes lower, which can further contribute to the cost reduction of the new electric power unit P. Moreover, even if the front case half 25 has a lid shape, the rigidity is enhanced by the electric motor 10 attached thereto, so that the swing arm 56 can be supported without any problem in strength.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the scope of the present invention. For example, the first gear case portion 20 can be divided symmetrically. A helical gear can be used instead of the spar drive gear 15 and the spar driven gear 16, and a face gear or a hypoid gear can be used instead of the bevel drive gear 17 and the bevel driven gear 18. Further, instead of the ball bearings 33, 38, 46, 47, other types of bearings such as plain bearings, angular contact bearings, and roller bearings may be used. Furthermore, the present invention is also applicable to an automatic tricycle or a four-wheeled vehicle in which the rear axle 12 is projected to the left and right outer sides of the transmission case 19 and a pair of rear wheels are attached to both ends thereof.

P ... Electric power unit V ... Vehicle (motorcycle)
DESCRIPTION OF SYMBOLS 1 ...... Body frame 10 ... Electric motor 10a ... Rotor shaft 11 ... Propeller shaft 12 ... Rear axle 13 ... Primary reduction gear train 14 ... Secondary reduction gear train 15 ...・ Drive gear of primary reduction gear train (spar drive gear)
16 ... Driven gear of primary reduction gear train (spar driven gear)
17 ... Secondary reduction gear train drive gear (bevel drive gear)
18 ... Secondary reduction gear train driven gear (bevel driven gear)
DESCRIPTION OF SYMBOLS 19 ... Transmission case 20 ... 1st gear case part 21 ... Shaft case part 22 ... 2nd gear case part 23 ... 1st opening part 24 ... 2nd opening part 25 ... Front Case half 26 ... Rear case half 33 ... First bearing (first ball bearing)
38 ... 2nd bearing (2nd ball bearing)
39 ... Bearing holder 47 ... Bearing (ball bearing)
48 ... Rear axle holder

The other structure is the same configuration as the first embodiment, in FIG. 14, parts corresponding to the first embodiment and the description thereof is omitted here denoted by the same reference numerals.

Claims (8)

An electric motor (10), a propeller shaft (11) arranged parallel to the rotor shaft (10a) of the electric motor (10), and a vehicle (V) arranged at right angles to the propeller shaft (11) A rear axle (12) for driving a rear wheel (4), a primary reduction gear train (13) for reducing and transmitting the output of the rotor shaft (10a) to the front portion of the propeller shaft (11), A secondary reduction gear train (14) for reducing and transmitting the output of the propeller shaft (11) from its rear part to the rear axle (12) and the propeller shaft (11) while supporting the electric motor (10). ), A vehicle electric power unit comprising a primary reduction gear train (13) and a transmission case (19) that houses the secondary reduction gear train (14),
The transmission case (19) supports the electric motor (10), a first gear case portion (20) for housing the primary reduction gear train (13), and a rear portion of the first gear case portion (20). A shaft case portion (21) for receiving the propeller shaft (11), and a shaft case portion (21) for receiving the secondary reduction gear train (14) integrally connected to the rear portion of the shaft case portion (21). The secondary reduction gear train (14) is fixed to the drive gear (17) fixed to the propeller shaft (11) and the rear axle (12). And a driven gear (18) meshing with the drive gear (17). The propeller shaft (11) and the drive gear (17) are connected to the shaft case portion (21) at the front portion of the shaft. A first bearing (33) for supporting the propeller shaft (11) adjacent to the drive gear (17) and the shaft case portion (21) or the second gear case. A first opening (23) for mounting on the part (22) is provided, and the driven gear (17) is provided on one side of the second gear case part (22) to the second gear case part (22). A second opening (24) is provided for insertion and for mounting a rear axle holder (48) for holding a bearing (47) for supporting the rear axle (12), and the shaft case (21) and the second An electric power unit for a vehicle, wherein the gear case portion (22) is integrally molded into a single part. In the vehicle electric power unit according to claim 1,
An electric power unit for a vehicle, wherein a bearing holder (39) for holding a second bearing (38) for supporting a front portion of the propeller shaft (11) is attached to the first opening (23). . The vehicle electric power unit according to claim 2,
The first gear case part (20) is detachably joined to the front end of the shaft case part (21), and the bearing holder (39) is formed integrally with the first gear case part (20). Electric power unit for vehicles. In the vehicle electric power unit according to claim 1,
The second bearing (38) that supports the front portion of the propeller shaft (11) is mounted on the front portion of the first gear case portion (20) that supports the electric motor (10). Electric power unit for vehicles. In the electric power unit for vehicles according to any one of claims 1 to 4,
The first gear case part (20) is detachably joined to a front case half (25) supporting the electric motor (10) and a rear end of the front case half (25), and the shaft case part An electric power unit for a vehicle comprising the rear case half (26) connected to the front end of (21). In the vehicle electric power unit according to claim 1,
An electric power unit for a vehicle, wherein the propeller shaft (11) and the drive gear (17) of the secondary reduction gear train (14) are integrally formed as one component. In the vehicle electric power unit according to claim 1,
The electric power unit for a vehicle, wherein the rear axle (12) and the driven gear (18) of the secondary reduction gear train (14) are integrally formed as one component. In the vehicle electric power unit according to any one of claims 1 to 7,
The transmission case (19) is made of an Al alloy, the propeller shaft (11) is made of steel, the drive gear (15) and the driven gear (16) constituting the primary reduction gear train (13) are spur gears or helical gears, The vehicular electric power unit characterized in that the thermal expansion difference in the longitudinal direction of the transmission case (19) and the propeller shaft (11) is absorbed by the meshing portion of the drive gear (15) and the driven gear.

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