JP2020158012A - Electrically-driven saddle-riding type vehicular power unit - Google Patents

Abstract

To make it possible to achieve downsizing and lightening while maintaining high rotation angle detection accuracy of an electric motor in an electrically-driven saddle-riding type vehicular power unit comprising a speed reduction gear mechanism which has a first gear fixed to a motor shaft of which an axial one side is coaxially connected to a rotor of the electric motor, a second gear which engages with the first gear and is fixed to an intermediate shaft, a third gear fixed to the intermediate shaft, and a fourth gear which engages with the third gear and is fixed to an output shaft, and is accommodated in a gear case.SOLUTION: A resolver 76 is provided at the other end part of a motor shaft 38, and a second gear 42 is located on an electric motor 25 side with respect to a third gear 43.SELECTED DRAWING: Figure 2

Description

The present invention includes a motor shaft whose one end side in the axial direction is coaxially connected to the rotor of an electric motor, an output shaft that can rotate around an axis parallel to the motor shaft so as to transmit power to the drive wheels, and the motor. A first gear fixed to the shaft, an intermediate shaft rotatable around an axis parallel to the motor shaft and the output shaft, and a second gear meshed with the first gear and fixed to the intermediate shaft. A gear case having a third gear formed to have a diameter smaller than that of the second gear and fixed to the intermediate shaft, and a fourth gear that meshes with the third gear and is fixed to the output shaft. The present invention relates to a power unit for an electric saddle-mounted vehicle having a reduction gear mechanism housed therein.

Patent Document 1 provides a power unit for an electric saddle-mounted vehicle in which the rotational power output from the electric motor is decelerated by a reduction gear mechanism and transmitted to the rear wheel side.

Japanese Patent No. 5356087

By the way, in order to control the rotation angle of the electric motor, it is necessary to detect the rotation angle of the electric motor. In the one disclosed in Patent Document 1, the rotation angle sensor for detecting the rotation angle of the rotor of the electric motor is described above. It is arranged in the case of the electric motor at a position close to the coil of the stator. However, if a leakage flux is generated from the coil at a position close to the coil, the detection accuracy of the rotation angle sensor may decrease.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a power unit for an electric saddle-riding vehicle capable of reducing the size and weight while maintaining high rotation angle detection accuracy of the electric motor. ..

In order to achieve the above object, the present invention rotates around a motor shaft whose one end side in the axial direction is coaxially connected to the rotor of the electric motor and an axis parallel to the motor shaft so as to transmit power to the drive wheels. A possible output shaft, a first gear fixed to the motor shaft, an intermediate shaft that can rotate around the motor shaft and an axis parallel to the output shaft, and the intermediate shaft that meshes with the first gear. A second gear fixed to the second gear, a third gear formed to have a diameter smaller than that of the second gear and fixed to the intermediate shaft, and a third gear that meshes with the third gear and is fixed to the output shaft. In an electric saddle-mounted vehicle power unit having four gears and having a reduction gear mechanism housed in a gear case, a resolver is arranged at the other end of the motor shaft, and the electric motor is more than the third gear. The first feature is that the second gear is arranged on the side.

Further, in the present invention, in addition to the configuration of the first feature, two places separated in the axial direction of the motor shaft are rotatably supported by the gear case via a motor shaft bearing, and the motor is supported by the motor shaft. An in-shaft oil passage having an introduction port on the end surface of the other end of the shaft and extending coaxially with the motor shaft, and the in-shaft oil on the motor shaft bearing side of the pair of the motor shaft bearings closer to the electric motor. The second feature is that a bearing oil passage for guiding oil from the passage is provided, and the gear case is provided with an in-case oil passage connected to the introduction port of the in-shaft oil passage.

In the present invention, in addition to the configuration of the first or second feature, the gear case has an inner wall arranged on the electric motor side along a plane orthogonal to the axis of the motor shaft, and the electric motor on the inner wall. It has an outer wall facing from the opposite side, and the motor shaft is rotatably supported by the inner wall via a first motor shaft bearing and rotatably supported by the outer wall via a second motor shaft bearing. The intermediate shaft is rotatably supported on the inner wall via a first intermediate shaft bearing and rotatably supported on the outer wall via a second intermediate shaft bearing, so that the outer surface of the outer wall is supported by the outer wall. The third feature is that it is formed flat.

The fourth feature of the present invention is that, in addition to the configuration of the second feature, an oil temperature sensor for detecting the oil temperature of the oil flowing through the oil passage in the case is attached to the gear case.

Further, in addition to the configuration of the second or fourth feature, the present invention has a fifth feature that an oil filter interposed in the middle of the oil passage in the case is attached to the gear case.

According to the first feature of the present invention, since the resolver is arranged at the other end of the motor shaft in which one end side in the axial direction is fixed to the rotor of the electric motor, the resolver is arranged at a position separated from the electric motor. Therefore, it is possible to prevent the resolver from deteriorating the accuracy of rotation angle detection by making it less susceptible to the influence of the leakage flux from the coil of the electric motor. Moreover, since the second and third gears fixed to the intermediate shaft in the reduction gear mechanism are arranged on the electric motor side of the third gear, they are fixed to the motor shaft and mesh with the second gear. It is possible to arrange the first gear to be closer to the electric motor, and even in a structure in which the resolver is arranged at the other end in the axial direction of the motor shaft, it is possible to avoid an increase in the shaft length of the motor shaft, and the gear case and thus It can contribute to reducing the size and weight of the power unit.

Further, according to the second feature of the present invention, a pair of motors interposed between the motor shaft and the gear case by the in-case oil passage provided in the gear case and the in-shaft oil passage and the bearing oil passage provided in the motor shaft. Of the shaft bearings, the motor shaft bearing closer to the electric motor can be lubricated, and an oil passage can be easily formed in the gear case and by using the motor shaft.

According to the third feature of the present invention, both ends of the motor shaft and the intermediate shaft are rotatably supported by the inner wall and the outer wall of the gear case, and the outer surface of the outer wall is flat, so that the axes of the motor shaft and the intermediate shaft are flat. The width of the gear case can be narrowed in the direction along the above to improve the aerodynamic performance and the design.

According to the fourth feature of the present invention, the oil temperature sensor for detecting the oil temperature of the oil passage in the case can be attached to the gear case, and the oil temperature sensor can be arranged by effectively utilizing the empty space.

Further, according to the fifth feature of the present invention, since the oil filter interposed in the middle of the oil passage in the case is attached to the gear case, the oil filter can be arranged by effectively utilizing the empty space.

It is a left side view of the electric motorcycle of the 1st embodiment. It is a cross-sectional view taken along the line 2-2 of FIG. It is sectional drawing corresponding to FIG. 2 of the 2nd Embodiment.

Embodiments of the present invention will be described with reference to the accompanying drawings. In the following explanation, front and rear, left and right, and up and down shall refer to the directions seen by the occupants riding the electric motorcycle.

The first embodiment of the present invention will be described with reference to FIGS. 1 and 2. First, in FIG. 1, the body frame F included in the electric motorcycle, which is an electric saddle-riding vehicle, has a front wheel WF at the lower end. A head pipe 7 that rotatably supports a front fork 5 that supports the shaft and a steering handle 6 that is connected to the front fork 5, a main frame 8 that extends downward from the head pipe 7, and the main frame 8. A pair of left and right pivot frames 9 that are integrally connected to the rear end and extend downward, a pair of left and right seat frames 10 that extend rearward from the rear end of the main frame 8, and an upper portion of the pivot frame 9 and the seat frame. An auxiliary frame 11 for connecting the rear portions of the 10 is provided.

In the pivot frame 9, the front end portion of the swing arm 12 that pivotally supports the rear wheel WR, which is a drive wheel, at the rear end portion is swingably supported via the support shaft 13. A rear cushion 15 is provided between the support stay 14 fixed to the rear end of the main frame 8 and the rear of the swing arm 12.

The main frame so that the power unit P that exerts the power to drive the rear wheel WR is supported by the pair of left and right hanger plates 16 attached to the upper portion of the pivot frame 9 and the lower portion of the pivot frame 9. It is placed below 8. The power unit P has an output shaft 40 protruding to the left in the vehicle width direction, a drive sprocket 17 fixed to the protruding end of the output shaft 40, and a driven sprocket fixed to the axle of the rear wheel WR. An endless drive chain 19 is wound around the 18.

Below the mainframe 8 and diagonally above the front side of the power unit P, a plurality of batteries 20 for supplying power to the power unit P and a PDU (Power Delivery Unit) for controlling the power supplied to the power unit P. 21 is arranged. Further, an electrical component 22 is arranged on the main frame 8, and an upper cover 23 that covers the electrical component 22 and a part of the battery 20 is attached to the main frame 8 and arranged behind the upper cover 23. The riding seat 24 is supported by the seat frame 10.

In FIG. 2, the power unit P includes an electric motor 25 that exerts rotational power to rotationally drive the rear wheel WR, and a reduction gear mechanism 26 that decelerates the rotational power of the electric motor 25 and transmits it to the rear wheel WR side. The reduction gear mechanism 26 is arranged on the left side in the vehicle width direction of the electric motor 25 on the right side in the vehicle width direction.

The electric motor 25 is arranged so that its rotation axis is horizontal in the vehicle width direction, and is configured as an inner rotor type having a rotor 27 and a stator 28 surrounding the rotor 27.

The rotor 27 is formed by coaxially fixing a permanent magnet 30 to a rotating shaft 29. Further, the stator 28 is formed by winding a coil 33 around a stator core 31 via a bobbin 32, and is arranged so as to coaxially surround the rotor 27.

The electric motor 25 is housed in a motor housing 34 except for a part of the rotating shaft 29, and the stator 31 is supported by the motor housing 34.

The reduction gear mechanism 26 is arranged around an axis parallel to the motor shaft 38 so as to transmit power to the rear wheel WR and the motor shaft 38 whose one end side in the axial direction is coaxially connected to the rotor 27 of the electric motor 25. A rotatable output shaft 40, a first gear 41 fixed to the motor shaft 38, an intermediate shaft 39 rotatable around an axis parallel to the motor shaft 38 and the output shaft 40, and the first gear. A second gear 42 that meshes with 41 and is fixed to the intermediate shaft 39, a third gear 43 that is formed to have a diameter smaller than that of the second gear 42 and is fixed to the intermediate shaft 39, and the third gear. It has a fourth gear 44 that meshes with 43 and is fixed to the output shaft 40, and is housed in the gear case 45.

One end side of the motor shaft 38 is coaxially and non-rotatably connected to the rotating shaft 29 of the rotor 27. The rotating shaft 29 is coaxially provided with a nut insertion hole 48 formed in a diameter larger than that of the connecting hole 47 while forming an annular step portion 49 between the connecting hole 47 and the connecting hole 47. Be done. On the other hand, on one end side of the motor shaft 38 in the axial direction, there is a connecting shaft portion 38a that is inserted into the connecting hole 47 and spline-coupled, and the connecting shaft portion 38a that penetrates into the nut insertion hole 48. A screw shaft portion 38b that is coaxially connected and formed to have a diameter smaller than that of the connecting shaft portion 38a is provided coaxially, and a nut 51 having a washer 50 interposed between the step portion 49 and the nut 51 is a nut insertion hole. By screwing into the screw shaft portion 38b in 48 and tightening the nut 51, one end side of the motor shaft 38 is coaxially connected to the rotor 27.

The gear case 45 is configured such that a first case member 52 arranged on the right side in the vehicle width direction and a second case member 53 arranged on the left side in the vehicle width direction of the first case member 52 are mutually fastened. A gear chamber 46 for accommodating the reduction gear mechanism 26 is formed in the gear case 45.

The first case member 52 has an inner wall 52a arranged on the electric motor 25 side along a plane orthogonal to the axis of the motor shaft 38, and a cylindrical first case projecting from the inner wall 52a toward the electric motor 25. The first side wall 52b and the tubular second side wall 52c which is arranged on the rear side of the first side wall 52b and projects to the side opposite to the electric motor 25 are integrally provided.

The motor housing 34 is coupled to the first side wall 52b by a plurality of first bolts 36 so as to cover the inner wall 52a, the first side wall 52b, and the electric motor 25 from the side opposite to the speed reduction mechanism 26. The stator 28 is fastened to a plurality of boss portions 52d projecting from the first side wall 52b with a second bolt 37.

The second case member 53 includes an outer wall 53a that faces the inner wall 52a from the side opposite to the electric motor 25, and a tubular third side wall 53b that projects from the outer circumference of the outer wall 53a toward the second side wall 52c. The gear case 45 is formed by fastening the third side wall 53b and the protruding end portion of the second side wall 52c with a plurality of third bolts 54.

The inner wall 52a of the first case member 52 is provided with a first bearing housing 56 having a first through hole 55, and the motor shaft 38 rotatably penetrates the first through hole 55 and the motor shaft 38. A first ball bearing 57 as a first motor shaft bearing is interposed between the first bearing housing 56, and a first annular seal member 59 forming an annular chamber 60 with the first ball bearing 57. Is interposed between the rotating shaft 29 of the electric motor 25 and the inner wall 52a. The first ball bearing 57 has a first shield 58 and is configured to have a seal, and the first shield 58 is arranged on the first ball bearing 57 on the side opposite to the annular chamber 60. Ru.

A second bearing housing 62 having a recess 61 into which the other end of the motor shaft 38 is inserted is provided on the inner surface of the outer wall 53a of the second case member 53, and the second bearing housing 62 and the motor shaft A second ball bearing 63 as a second motor shaft bearing is interposed between the 38 and the 38. The second ball bearing 63 has a second shield 64 and is configured to have a seal, and the second shield 64 is arranged at the end of the second ball bearing 63 on the gear chamber 46 side. ..

The inner wall 52a is provided with a third bearing housing 65 that cooperates with a part of the first bearing housing 56, and the outer wall 53a is provided with a fourth bearing that cooperates with a part of the second bearing housing 62. A housing 66 is provided, and a third ball bearing 67 as a first intermediate shaft bearing is interposed between the third bearing housing 65 and the intermediate shaft 39, and between the fourth bearing housing 66 and the intermediate shaft 39. Is intervened with a fourth ball bearing 68 as a second intermediate shaft bearing.

The inner wall 52a is provided with a fifth bearing housing 69 that cooperates with a part of the third bearing housing 66, and the outer wall 53a is provided with a sixth bearing that cooperates with a part of the fourth bearing housing 66. The housing 70 is provided so as to have a second through hole 71, and a fifth ball bearing 72 is interposed between one end of the output shaft 40 and the fifth bearing housing 69. Further, the intermediate shaft 39 rotatably penetrates the second through hole 71, and a sixth ball bearing 73 is interposed between the sixth bearing housing 70 and the intermediate shaft 39. A second annular seal member 74 is interposed between the outer wall 53a and the intermediate shaft 39 on the outer side of the sixth ball bearing 73. Further, the drive sprocket 17 is fixed to the protruding end of the output shaft 40 from the outer wall 53a.

A resolver 76 for detecting the rotation angle of the electric motor 25 is arranged at the other end of the motor shaft 38 in the recess 61 of the outer wall 53a of the second case member 53. The resolver 76 includes a small rotor 77 fixed to the motor shaft 38, and a small stator 78 attached to the inner circumference of the recess 61 so as to surround the small rotor 77.

Moreover, in the reduction gear mechanism 26, the second gear 42 is arranged closer to the electric motor 25 than the third gear 43 with respect to the third gear 43 integrally provided on the intermediate shaft 39, and is intermediate to the third gear 43. The second gear 42 is fixed to the shaft 39, and in this embodiment, the inner race 67a of the third ball bearing 67 and the second gear 42 whose axial movement is restricted by the third gear 43 are described. It is spline-coupled to the intermediate shaft 39.

The motor shaft 38 is provided with an in-shaft oil passage 80 having an introduction port 80a leading into the recess 61 on the end surface of the other end of the motor shaft 38 and extending coaxially with the motor shaft 38. Of the first and second ball bearings 63, the annular chamber 60 and the in-shaft oil passage 80 are connected so as to guide oil from the in-shaft oil passage 80 to the first ball bearing 57 side closer to the electric motor 25. A bearing oil passage 81 is provided.

An oil dropping hole (not shown) for dropping oil from above is provided in the meshing portion of the third gear 43 and the fourth gear 44 on the upper portion of the gear case 45, and the third and fourth gears 43 and 44 are provided. The meshing portions of the first and second gears 41 and 42 are also lubricated by the oil scattered as the intermediate shaft 39 rotates.

By the way, the outer surface of the outer wall 53a of the gear case 45 is formed flat, and the oil passage 82 inside the case is provided on the outer wall 53a of the gear case 45, and the oil passage 82 inside the case communicates with the recess 61. The in-shaft oil passage 80 is connected to the in-case oil passage 82 via the recess 61.

Further, an oil temperature sensor 84 that detects the oil temperature of the oil flowing through the oil passage in the case is attached to the outer wall 53a of the gear case 45.

Next, the operation of the first embodiment will be described. The reduction gear mechanism 26 that constitutes the power unit P together with the electric motor 25 is attached to the motor shaft 38 whose one end side in the axial direction is coaxially connected to the rotor 27 of the electric motor 25. A first gear 41 that is fixedly attached, a second gear 42 that is fixedly attached to an intermediate shaft 39 that is rotatable around an axis parallel to the motor shaft 38 and the output shaft 40 and meshes with the first gear 41, and a second gear. It has a third gear 43 formed to have a diameter smaller than that of the gear 42 and fixed to the intermediate shaft 39, and a fourth gear 44 that meshes with the third gear 43 and is fixed to the output shaft 40. Since the resolver 76 is arranged at the other end of the motor shaft 38, the resolver 76 is arranged at a position separated from the electric motor 25, and the electric motor 25 is accommodated in the gear case 45. It is possible to prevent the resolver 76 from deteriorating the accuracy of rotation angle detection by making it less susceptible to the influence of the leakage magnetic flux from the coil 33.

Moreover, since the second and third gears 42 and 43 of the gear reduction mechanism 26 are fixed to the intermediate shaft 39 so that the second gear 42 is arranged closer to the electric motor 25 than the third gear 43. The first gear 41, which is fixed to the motor shaft 38 and meshes with the second gear 42, can be arranged closer to the electric motor 25, and the resolver 76 is arranged at the other end in the axial direction of the motor shaft 38. In terms of structure, it is possible to avoid an increase in the shaft length of the motor shaft 38 and contribute to reducing the size and weight of the gear case 45 and thus the power unit P.

Further, two points separated in the axial direction of the motor shaft 38 are rotatably supported on the gear case 45 via the first and second ball bearings 57 and 63, and the motor shaft 38 is supported by the motor shaft 38. An in-shaft oil passage 80 having an introduction port 80a on the end surface of the other end and extending coaxially with the motor shaft 38, and a first ball bearing of the first and second ball bearings 57 and 63 closer to the electric motor 25. A bearing oil passage 81 for guiding oil from the in-shaft oil passage 80 is provided on the 57 side, and an in-case oil passage 82 connected to the introduction port 80a of the in-shaft oil passage 80 is provided in the gear case 45. Therefore, the first ball bearing 57 can be lubricated by the in-case oil passage 82 provided in the gear case 45, the in-shaft oil passage 80 and the bearing oil passage 81 provided in the motor shaft 38, and in the gear case 45 and in the bearing case 45. An oil passage can be easily formed by using the motor shaft 38.

Further, the gear case 45 has an inner wall 52a arranged on the electric motor 25 side along a plane orthogonal to the axis of the motor shaft 38, and an outer wall 53a facing the inner wall 52a from the side opposite to the electric motor 25. The motor shaft 38 is rotatably supported by the inner wall 52a via the first ball bearing 57 and rotatably supported by the outer wall 53a via the second ball bearing 63, and the intermediate shaft 39 is provided. Is rotatably supported by the inner wall 52a via the third ball bearing 67 and rotatably supported by the outer wall 53a via the fourth ball bearing 68, so that the outer surface of the outer wall 53a is formed flat. , The width of the gear case 45 can be narrowed in the direction along the axes of the motor shaft 38 and the intermediate shaft 39 to improve the aerodynamic performance and the design.

Further, since the oil temperature sensor 84 that detects the oil temperature of the oil flowing through the oil passage 82 in the case is attached to the gear case 45, the oil temperature sensor 84 can be arranged by effectively utilizing the empty space.

As a second embodiment of the present invention, as shown in FIG. 3, an oil filter 85 interposed in the middle of the oil passage 82 in the case may be attached to the outer wall 53a of the gear case 45. Then, the oil filter 85 can be arranged by effectively utilizing the empty space.

Further, the oil temperature sensor 84 and the filter 85 may both be attached to the outer wall 53a of the gear case 45.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various design changes are made without departing from the present invention described in the claims. Is possible.

25 ... Electric motor 26 ... Reduction gear mechanism 27 ... Rotor 38 ... Motor shaft 39 ... Intermediate shaft 40 ... Output shaft 41 ... 1st gear 42 ... 2nd gear 43 ... 3rd gear 44 ... 4th gear 45 ... Gear case 52a ... Inner wall 53a ... Outer wall 57 ... 1st ball bearing 63 ... 1st motor shaft bearing 2nd motor shaft bearing, 2nd ball bearing 67 ... 1st intermediate shaft bearing, 3rd ball bearing 68 ... 2nd intermediate shaft bearing, 4th ball bearing 76 ... Resolver 80.・ ・ In-shaft oil passage 80a ・ ・ ・ Introduction port 81 ・ ・ ・ Bearing oil passage 82 ・ ・ ・ Case inner oil passage 84 ・ ・ ・ Oil temperature sensor 85 ・ ・ ・ Oil filter P ・ ・ ・ Power unit WR ・ ・ ・ Drive Rear wheel which is a wheel

Claims (5)

A motor shaft (38) whose one end side in the axial direction is coaxially connected to the rotor (27) of the electric motor (25), and an axis parallel to the motor shaft (38) so as to transmit power to the drive wheels (WR). Around an output shaft (40) that can rotate around, a first gear (41) fixed to the motor shaft (38), and an axis parallel to the motor shaft (38) and the output shaft (40). The diameter is smaller than that of the rotatable intermediate shaft (39), the second gear (42) that meshes with the first gear (41) and is fixed to the intermediate shaft (39), and the second gear (42). A third gear (43) formed and fixed to the intermediate shaft (39) and a fourth gear (44) that meshes with the third gear (43) and is fixed to the output shaft (40). In a power unit for an electric saddle-mounted vehicle having a reduction gear mechanism (26) housed in a gear case (45), a resolver (76) is arranged at the other end of the motor shaft (38). A power unit for an electric saddle-riding vehicle, wherein the second gear (42) is arranged closer to the electric motor (25) than the third gear (43). Two points separated in the axial direction of the motor shaft (38) are rotatably supported by the gear case (45) via motor shaft bearings (57, 63), and the motor shaft (38) is supported by the motor shaft (38). An in-shaft oil passage (80) having an introduction port (80a) on the end surface of the other end of (38) and extending coaxially with the motor shaft (38), and a pair of the motor shaft bearings (57, 63). A bearing oil passage (81) for guiding oil from the in-shaft oil passage (80) is provided on the motor shaft bearing (57) side closer to the electric motor (25), and the shaft is provided in the gear case (45). The power unit for an electric saddle-mounted vehicle according to claim 1, wherein a case inner oil passage (82) connected to the introduction port (80a) of the inner oil passage (80) is provided. The gear case (45) has an inner wall (52a) arranged on the electric motor (25) side along a plane orthogonal to the axis of the motor shaft (38), and the electric motor (25) on the inner wall (52a). ), The motor shaft (38) is rotatably supported by the inner wall (52a) via a first motor shaft bearing (57) and has an outer wall (53a) facing from the opposite side. The outer wall (53a) is rotatably supported via a second motor shaft bearing (63), and the intermediate shaft (39) is rotatably supported by the inner wall (52a) via a first intermediate shaft bearing (67). 1. The outer wall (53a) is rotatably supported by a second intermediate shaft bearing (68), and the outer surface of the outer wall (53a) is formed flat. Alternatively, the power unit for an electric saddle-mounted vehicle according to 2. The electric saddle-mounted vehicle according to claim 2, wherein an oil temperature sensor (84) for detecting the oil temperature of the oil flowing through the oil passage (82) in the case is attached to the gear case (45). Power unit. The power unit for an electric saddle-riding vehicle according to claim 2 or 4, wherein an oil filter (85) interposed in the middle of the oil passage (82) in the case is attached to the gear case (45).