Vehicle drive device

Abstract

A vehicle drive device is provided with: a first electric motor and a second electric motor as travel drive sources for a vehicle; a transmission having an input shaft to which torque is input, a transmission mechanism for changing the rotation speed of the input shaft, and a transmission housing for accommodating the input shaft and the transmission mechanism; a rotating shaft extending coaxially with the input shaft around the axis outside the transmission housing and connected to the input shaft; a first power transmission unit that transmits the torque of the first motor to the rotating shaft; and a second power transmission unit that transmits the torque of the second motor to the rotating shaft. The first motor and the second motor are disposed at substantially symmetrical positions with the rotation axis as an axis of symmetry.

Description

Technical Field

[0001] The present invention relates to a vehicle driving device having an electric motor as a driving source for traveling. Background Art

[0002] In the past, there have been known vehicles with a plurality of motors for driving the vehicle. As such a vehicle, for example, a vehicle described in Patent Document 1 has a motor (hub motor) built into each wheel of the vehicle, and each wheel is driven to rotate by the driving of each motor.

[0003] As described in Patent Document 1, when multiple motors for driving the vehicle are configured as in-wheel motors, the driving force of each motor becomes the driving force of each wheel. Therefore, in order to increase the driving force of the wheel, a large motor is required, which leads to an increase in the size of the device.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent document 1: Japanese Patent No. 6355927 (JP6355927B). Summary of the invention

[0007] A vehicle drive device according to one technical solution of the present invention comprises: a first motor and a second motor, which serve as a driving source for driving the vehicle; a transmission having an input shaft to which torque is input, a speed change mechanism for changing the rotation speed of the input shaft, and a transmission case for accommodating the input shaft and the speed change mechanism; a rotating shaft, which is outside the transmission case, extends coaxially with the input shaft and is centered on the axis, and is connected to the input shaft; a first power transmission part, which transmits the torque of the first motor to the rotating shaft; and a second power transmission part, which transmits the torque of the second motor to the rotating shaft. The first motor and the second motor are arranged at substantially symmetrical positions with the rotating shaft as a symmetric axis. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The objects, features and advantages of the present invention will be further clarified through the following description of the embodiments in conjunction with the accompanying drawings.

[0009] Figure 1 It is a side view of a vehicle to which the vehicle drive device according to the embodiment of the present invention is applied.

[0010] Figure 2 yes Figure 1 II direction view.

[0011] Figure 3 It is a perspective view showing the overall structure of a vehicle drive device according to an embodiment of the present invention.

[0012] Figure 4It is a side view showing the overall structure of the vehicle drive device according to the embodiment of the present invention.

[0013] Figure 5 It is an exploded perspective view of a drive unit which is a part of the vehicle drive device according to the embodiment of the present invention.

[0014] Figure 6 yes Figure 5 A cross-sectional view of the main parts of the drive unit.

[0015] Fig. 7A It is composed Figure 5 A perspective view of the housing of the drive unit.

[0016] Figure 7B It is from Fig. 7A Perspective views of the housing viewed from different directions.

[0017] Figure 8 It is composed Figure 5 A three-dimensional view of a support frame of a drive unit.

[0018] Fig. 9 It is composed Figure 5 A perspective view of a bracket of a drive unit.

[0019] Fig.10 It is shown Figure 5 A cross-sectional view of the structure of a connection portion between a rotating shaft of a drive unit and an input shaft of a transmission. DETAILED DESCRIPTION

[0020] The following reference Figures 1 to 10 The vehicle drive device of the embodiment of the present invention is a device for driving a vehicle and can be applied to various vehicles such as passenger cars, trucks, and work vehicles. As an example, the application of the vehicle drive device to a four-wheel truck is described below.

[0021] Figure 1 2 is a side view of a vehicle (truck) 200 equipped with the vehicle drive device 100 according to the embodiment of the present invention. Figure 2 2 is a bottom view of a vehicle 200 showing a schematic structure of a vehicle drive device 100 ( Figure 1 II direction view). It should be noted that Figure 1 , 2 The front-rear direction (length direction), the left-right direction (width direction), and the up-down direction (height direction) of the vehicle 200 are indicated by arrows.

[0022] like Figure 1As shown, the vehicle 200 has a pair of left and right front wheels 201, a pair of left and right rear wheels 202, a cab 203 arranged above the front wheels 201, a chassis (body frame) 204 forming the skeleton of the vehicle 200, and a cabin 205 arranged above the chassis 204. The vehicle 200 is a rear-wheel drive vehicle in which the front wheels 201 are configured as driven wheels and the rear wheels 202 are configured as driving wheels, and the rear wheels 202 are driven by the vehicle drive device 100. The vehicle drive device 100 is arranged below the chassis 204 and near the rear wheels 202.

[0023] For your convenience, Figure 2 The rear wheels 202 and the left and right drive shafts 206 connected to the rear wheels 202 are shown by double-dashed lines. As for the chassis 204, only the outermost contour is shown by solid lines. Figure 2 As shown, the vehicle drive device 100 is disposed between the left and right rear wheels 202. The front end of the vehicle drive device 100 is located forward of the front ends of the rear wheels 202, and the rear end is located backward of the drive shaft 206 and forward of the rear ends of the rear wheels 202.

[0024] The vehicle drive device 100 includes a drive unit 1, a transmission 2, and a differential mechanism 3. The drive unit 1 is mounted on the left end of the transmission 2, and the torque output from the drive unit 1 is input to the input shaft of the transmission 2. The transmission 2 changes the speed of the input shaft at a predetermined speed ratio. The differential mechanism 3 is disposed at the rear of the transmission 2, and distributes the torque output from the transmission 2 to the left and right, and transmits it to the left and right drive shafts 206. As a result, the drive shaft 206 rotates, and the left and right rear wheels 202 are driven.

[0025] The vehicle drive device 100 is supported by a plurality of support parts 211 to 213 provided at the bottom of the chassis 204. Specifically, the vehicle drive device 100 is supported by a support part 211 provided at the right front, a support part 212 provided at the left front, and a support part 213 provided at the center and rear in the left-right direction via a well-known bracket mechanism.

[0026] Originally, the engine is connected to the transmission 2. If the drive unit 1 is connected instead of the engine, the drive unit 1 is configured to be substantially the same size as the engine. Therefore, the drive unit 1 can be directly arranged in the installation space of the engine, and the bracket of the engine can be directly used as the support part of the vehicle drive device 100. As a result, an engine vehicle having an engine as a driving source can be easily and inexpensively changed to an electric vehicle having the drive unit 1.

[0027] Figure 3 1 is a perspective view showing the overall structure of the vehicle drive device 100 (viewed from the left front and from above). Figure 2 , 3As shown in FIG. 1 , the transmission 2 includes a transmission case 20 and a speed change mechanism 21 accommodated in the transmission case 20. Although not shown in the figure, the speed change mechanism 21 includes an input shaft and an output shaft rotatably supported in the transmission case 20 and extending parallel to each other in the left-right direction, and a multi-stage gear that transmits the rotation of the input shaft to the output shaft. The transmission case 20 is configured to accommodate the input shaft, the output shaft, and the multi-stage gear, with an axis CL1 extending in the left-right direction (see FIG. 1 ). Figure 4 ) is a roughly cylindrical shape with the center being

[0028] Figure 4 is a side view of the vehicle drive device 100 as seen from the left ( Figure 1 ). Figure 4 As shown, the differential mechanism 3 is arranged to bulge out from the transmission 2 to the rear. The bottom surface of the differential mechanism 3 is located at the same or substantially the same level as the bottom surface of the transmission 2. Behind the transmission 2, the drive shaft 206 protrudes from the left and right ends of the differential mechanism 3 to the left and right directions.

[0029] The vehicle drive device 100 according to the present embodiment is characterized in the structure of the drive unit 1 . Figure 5 is an exploded perspective view of the drive unit 1. Figures 3 to 5 As shown, the drive unit 1 has a pair of front and rear motors 11, 12, a support frame 13 supporting the motors 11, 12, a shell 14 supporting the support frame 13, a rotating shaft 15 supported inside the shell 14 in a rotatable manner, a pair of power transmission parts 16, 17 respectively transmitting the torque of the motors 11, 12 to the rotating shaft 15, and a bracket 18 for mounting the drive unit 1 on the chassis 204.

[0030] The rotating shaft 15 extends in the left-right direction along the axis CL1 passing through the center of the rotating shaft 15. It should be noted that, hereinafter, the direction parallel to the axis CL1 is sometimes referred to as the axial direction, the direction radially extending from the axis CL1 (the direction perpendicular to the axis CL1) is sometimes referred to as the radial direction, and the direction of extension of a circle centered on the axis CL1 is sometimes referred to as the circumferential direction.

[0031] The motors 11 and 12 are electric motors of the same structure, for example, three-phase AC synchronous motors. Figure 1 As shown, a battery 250 is mounted in front of the vehicle drive device 100 and below the chassis 204. The DC power of the battery 250 is converted into three-phase AC power by a power conversion circuit (not shown) and supplied to the motors 11 and 12. As a result, a pair of motors 11 and 12 are driven simultaneously. It should be noted that the torque output from the motors 11 and 12 is the same when the vehicle is running. By using two motors 11 and 12 as the driving source, a large driving torque can be generated without using a large motor.

[0032] like Figure 4 As shown in FIG. 1 , one motor 11 is arranged in front of the rotating shaft 15 and below the rotating shaft 15. The bottom surface of the motor 11 and the bottom surface of the transmission 2 are located on the same horizontal plane. The other motor 12 is arranged behind the rotating shaft 15 and between the drive shaft 206 and the chassis 204. Thus, in this embodiment, the pair of motors 11 and 12 are arranged approximately symmetrically with respect to the rotating shaft 15 with the rotating shaft 15 as the symmetry axis. Thus, as shown in FIG. Figure 1 As shown, the angle (called the intersection angle) θ between a pair of line segments extending from the center of the rotating shaft 15 (axis CL1) to the center of the motors 11 and 12 becomes larger. The roughly symmetric here refers to the case where the intersection angle θ is greater than a specified angle θ1 (for example, 135°), and also includes the case of strict symmetry (that is, the intersection angle θ is 180°).

[0033] Assuming that the rear motor 12 is arranged above the drive shaft 206 without changing and the front motor 11 is arranged with the crossing angle θ being 180°, the bottom surface of the motor 11 is located below the bottom surface of the transmission 2, and the distance from the road surface to the motor 11 (the lowest ground clearance) becomes shorter. On the other hand, when the front motor 11 is arranged above the drive shaft 206, the bottom surface of the motor 11 is located below the bottom surface of the transmission 2. Figure 4 When the motor 12 is arranged with the crossing angle θ being 180° without changing its position, the motor 12 may interfere with the drive shaft 206. Therefore, the crossing angle θ is set to a value greater than the predetermined angle θ1 so that the motor 11 on the front side can be sufficiently clear of the ground while the motor 12 on the rear side is arranged without interfering with the drive shaft 206. Preferably, the crossing angle θ is set to a value as close to 180° as possible (180° if possible).

[0034] like Figure 5 As shown, the output shafts of the motors 11 and 12 extend in the left-right direction in parallel with the axis CL1, and drive pulleys 111 and 121 of the same structure are provided at their top ends (right ends). The rear motor 12 is arranged to the right of the front motor 11 by a predetermined length, and the drive pulley 121 is located to the right of the drive pulley 111 by a predetermined length. The distances from the axis CL1 to the output shafts of the motors 11 and 12 are equal to each other.

[0035] The power transmission parts 16 and 17 are arranged at positions offset from each other in the left-right direction. The power transmission part 16 on the left side has a driven pulley 161 having a larger diameter than the driving pulley 111 and an annular transmission belt 162. The transmission belt 162 is hung between the driven pulley 161 and the driving pulley 111 in front of it, and the rotation of the driving pulley 111 is decelerated and transmitted to the driven pulley 161 via the transmission belt 162. The power transmission part 17 on the right side has a driven pulley 171 having a larger diameter than the driving pulley 121 and an annular transmission belt 172. The transmission belt 172 is hung between the driven pulley 171 and the driving pulley 121 behind it, and the rotation of the driving pulley 121 is decelerated and transmitted to the driven pulley 171 via the transmission belt 172. The structures (diameter, width) of the driven pulleys 161 and 171 are the same, and the structures (length, width) of the transmission belts 162 and 172 are also the same.

[0036] The driven pulleys 161 and 171 are attached to the rotating shaft 15 so as to rotate integrally with the rotating shaft 15 . Figure 6 1 is a cross-sectional view of the main part of the drive unit 1 cut along the axis CL1. Figure 5 , 6 As shown, the outer peripheral surface of the rotating shaft 15 is formed in a stepped shape, and has a large diameter portion 151, a small diameter portion 152 extending rightward from the large diameter portion 151, and a connecting portion 153 on the left side of the large diameter portion 151. Figure 6 As shown, the inner ring of the ball bearing 41 is mounted on the outer peripheral surface of the large diameter portion 151. The outer ring of the ball bearing 41 is mounted on the inner peripheral surface of the substantially annular bearing support portion 141 centered on the axis CL1 provided in the housing 14. Thus, the rotating shaft 15 is rotatably supported in the housing 14 via the ball bearing 41.

[0037] The washer 42, the driven pulley 171, the sleeve 43 and the driven pulley 161 are respectively fitted in the outer peripheral surface of the small diameter portion 152 from the right side. The threaded hole 154 is provided at the left end of the rotating shaft 15, and the bolt 44 is threadedly engaged with the threaded hole 154. The washer 42, the driven pulley 171, the sleeve 43 and the driven pulley 161 are fixed by being clamped between the bearing surface of the bolt 44 and the left end surface of the large diameter portion 151. The inner ring of the bearing 41 is fixed by being clamped between the end surface of the step portion 151a provided on the outer peripheral surface of the large diameter portion 151 and the washer 42. The outer ring of the bearing 41 is fixed by being clamped between the side wall portion 142 extending radially inward from the left end of the bearing support portion 141 and the retaining ring (spring retaining ring) 45 fitted in the groove of the inner peripheral surface of the bearing support portion 141.

[0038] The housing 14 is configured as a substantially cylindrical shape as a whole so as to cover the periphery of the rotating shaft 15 and the driven pulleys 161, 171, etc. Figure 5As shown, the housing 14 has a base 143 (first end) provided at the right end, a flange 144 (second end) provided at the left end, and a side wall 145 extending in the left-right direction to connect the base 143 and the flange 144 .

[0039] The side wall portion 145 extends obliquely as it approaches the axis CL1 toward the left. The size of the flange portion 144 centered on the axis CL1, that is, the overall size of the flange portion 144 on a plane perpendicular to the axis CL1, is smaller than the overall size of the base portion 143 centered on the axis CL1. Figure 3 As shown, the base portion 143 is formed to have a substantially L-shaped cross section so as to cover the periphery of the left end portion of the transmission case 20 , thereby enabling the case 14 to be accurately positioned relative to the transmission case 20 .

[0040] Fig. 7A This is a three-dimensional view of the housing 14 as viewed from the left front and slightly above. Figure 7B This is a three-dimensional view of the housing 14 as viewed from the left rear and slightly below. Fig. 7A As shown, a plurality of through holes 143a and threaded holes 143b are provided in the circumferential direction on the base 143. The bolts passing through the through holes 143a are threadedly connected with the threaded holes of the flange portion of the transmission housing 20, and the bolts passing through the flange portion of the transmission housing 20 are threadedly connected with the threaded holes 143b, thereby the housing 14 is fastened to the left end surface of the transmission housing 20. It should be noted that only one of the through holes 143a and the threaded holes 143b may be provided on the base 143.

[0041] The housing 14 is not provided over the entire circumference with the axis CL1 as the center, but is provided by cutting off a portion of the circumference. Figure 4 The end surface 146 is cut by a virtual plane extending in the left-right direction substantially parallel to the axis CL1 and with reference line CL2 behind the axis CL1. Figure 7B As shown, the end surface 146 (shown by hatching for convenience) is located radially outward of the bearing support portion 141, and the base portion 143, the side wall portion 145, and a portion of the flange portion 144 are cut off by the end surface 146. The end surface 146 is provided with a plurality of threaded holes 146a.

[0042] like Figure 4 As shown, the cover 140 ( Figure 5 The cover 140 is fastened to the end surface 146 by means of a bolt 147 threadedly engaged with the threaded hole 146a. When the cover 140 is fastened to the end surface 146 of the housing 14, the rotating shaft 15 and the driven pulleys 161 and 171 ( Figure 6) etc. are surrounded by the entire circumference. In this way, the cover 140 and the housing 14 integrally surround the rotating shaft 15, the driven pulleys 161, 171, etc., and the cover 140 is sometimes treated as a part of the housing. That is, the housing 14 is sometimes treated as the first housing (main housing) and the cover 140 is treated as the second housing (sub-housing).

[0043] like Figure 5 As shown, the transmission belt 162 extends forward from the driven pulley 161, and the transmission belt 172 extends backward from the driven pulley 171. Fig. 7A , 7B As shown in FIG. 1 , a pair of upper and lower cutouts 148 are provided on the side wall portion 145 of the housing 14, corresponding to the position of the transmission belt 162, extending from the left end surface 144c (first end surface) of the flange portion 144 to the right with a predetermined depth. The cutouts 148 extend substantially parallel to the axis CL1, and their depth (length in the left-right direction) is equivalent to the width of the transmission belt 162. Thus, as shown in FIG. Figure 3 As shown, the drive belt 162 passes through the housing 14 via the cutout 148 , and the drive belt 162 can be driven without interfering with the housing 14 .

[0044] like Fig. 7A , 7B As shown in FIG. 1 , a substantially rectangular cutout 149 having a predetermined depth upward from the end surface 146 (second end surface) is provided on the side wall portion 145 of the housing 14 corresponding to the position of the transmission belt 172. Figure 5 As shown in FIG. 1 , the transmission belt 172 is located to the right of the transmission belt 162, and correspondingly, the cutout 149 is located to the right of the cutout 148. The width (length in the left-right direction) of the cutout 149 is equivalent to the width of the transmission belt 172. Figure 3 As shown, the transmission belt 172 passes through the housing 14 via the cutout 149, and the transmission belt 172 can be driven without interfering with the housing 14. The cutout 149 extends substantially perpendicularly to the axis CL1 and has a predetermined depth (length in the vertical direction). The depth of the cutout 149 can be shortened, and the cover 140 ( Figure 4 ) is provided with a cutout, and a transmission belt 172 is arranged between the cutout 149 of the housing 14 and the cutout of the cover 140. Since the cutout 149 is provided in the end surface 146, the depth of the cutout 149 can be easily shortened.

[0045] After the belt 172 is arranged through the cutout 149, the cover 140 is attached to the end surface 146 of the housing 14. When the cover 140 is attached to the housing 14, the inlet (lower end) of the cutout 149 is blocked by the cover 140, and the cutout 149 becomes a substantially rectangular opening.

[0046] like Figure 7BAs shown in FIG. 1 , a plurality of threaded holes 144a are provided on the left end surface of the flange portion 144. The bolt 181 ( Figure 4 ) are threadedly engaged with these threaded holes 144a, thereby fastening the support frame 13 to the left end surface of the flange portion 144. Figure 8 This is a three-dimensional view of the support frame 13 obtained by observing the support frame 13 from the left rear and slightly above. Figure 8 As shown, the support frame 13 includes a flange portion 131 and a pair of front and rear motor support portions 132 and 133 extending forward and rearward from the front end portion and the rear end portion of the flange portion 131 , respectively.

[0047] The flange portion 131 is formed into a substantially circular arc shape with the axis CL1 as the center, similarly to the flange portion 144 of the housing 14, and the right end surface of the flange portion 131 abuts against the left end surface of the flange portion 144. The motor support portions 132 and 133 are respectively formed into a substantially C-shape corresponding to the shape of the outer peripheral surface of the motors 11 and 12. The rear motor support portion 133 extends rearward from the periphery of the flange portion 131, and correspondingly, the front motor support portion 132 is provided to bulge to the left relative to the flange portion 131 in accordance with the positional offset of the transmission belts 162 and 172 in the left-right direction. That is, the motor support portion 132 and the motor support portion 133 are provided to be offset from each other in the left-right direction (the direction along the axis CL1).

[0048] A pair of through holes 134 are formed at both ends of the motor support portion 132 in the vertical direction. The motor 11 is connected to the motor 11 by bolts 135 ( Figure 3 ) is fixed to the motor support portion 132. A pair of through holes 136 are provided at both ends of the motor support portion 133 in the upper and lower directions, and the motor 12 is fixed by bolts 137 ( Figure 3 ) is fixed to the motor support portion 133.

[0049] The flange portion 131 and the motor support portion 132 overlapping the flange portion 131 are connected to the screw hole 144a ( Figure 7B ) positions correspondingly to the plurality of through holes 131a. Figure 4 As shown, a bracket 18 is installed on the left end surface of the support frame 13. Fig. 9 This is a three-dimensional view of the bracket 18 obtained by observing the bracket 18 from the right front obliquely. Fig. 9 As shown, the bracket 18 has a mounting portion 182 for mounting on the support frame 13, a mounting portion 183 for mounting on the chassis 204, and an arm portion 184 connecting the mounting portion 182 and the mounting portion 183. The arm portion 184 extends from the mounting portion 182 obliquely forward, leftward, and upward.

[0050] The mounting portion 182 is divided into two in the circumferential direction and is arranged at a position staggered in the left-right direction. The right end face of one of the mounting portions 182 (the right end face that protrudes further to the right) abuts against the left end face of the flange portion 131 of the support frame 13, and the right end face of the other abuts against the left end face of the motor support portion 132. A plurality of through holes 182a are provided at positions corresponding to the through holes 131a of the support frame 13. Figure 4 As shown, the bolt 181 passing through the through hole 182a of the bracket 18 and the through hole 131a of the support frame 13 is connected to the threaded hole 144a ( Figure 7B ) threaded connection, whereby the bracket 18 and the support frame 13 are fixed to the housing 14 at the same time.

[0051] Fig.10 1 is a cross-sectional view showing the structure of the connection portion between the rotating shaft 15 of the drive unit 1 and the transmission 2. For convenience, a portion of the transmission 2 is shown by a virtual line (two-dot chain line). Fig.10 As shown, the transmission 2 has an input shaft 23 extending in the left-right direction coaxially with the rotating shaft 15. Although not shown in the figure, not only the input shaft 23 but also an output shaft extending in the left-right direction parallel to the input shaft 23 is arranged in the transmission case 20. A multi-stage gear not shown is provided on the outer peripheral surface of the input shaft 23, and the gears mesh with the gears provided on the outer peripheral surface of the output shaft, thereby transmitting torque from the input shaft 23 to the output shaft.

[0052] The left end of the input shaft 23 protrudes to the left from the transmission case 20. The input shaft 23 is rotatably supported in the transmission case 20 via a pair of left and right bearings (ball bearings) 25 and 26. More specifically, a portion to the right of the left end of the input shaft 23 by a predetermined length and the right end of the input shaft 23 are supported by the bearings 25 and 26. A cylindrical shaft portion 27 is provided at the left end (top end) of the input shaft 23, and a shaft portion 28 having a larger diameter than the shaft portion 27 is provided on the right side of the shaft portion 27. A spline is formed on the outer peripheral surface of the shaft portion 28.

[0053] A bottomed hole 155 of a predetermined depth and substantially cylindrical in shape is provided at the connection portion 153 at the right end of the rotating shaft 15, with the axis CL1 as the center, from the right end surface of the rotating shaft 15 to the left. The bottomed hole 155 includes a hole portion 156 on the depth side of the bottomed hole 155 and a hole portion 157 which is larger in diameter than the hole portion 156 and is located on the right side of the hole portion 156. The diameter of the hole portion 156 is equal to (or substantially equal to) the diameter of the shaft portion 27, and the shaft portion 27 and the hole portion 156 are fitted without a gap (or substantially without a gap). A spline is formed on the inner circumferential surface of the hole portion 157, and the spline of the shaft portion 28 meshes with the spline of the hole portion 157. As a result, the torque is transmitted from the rotating shaft 15 to the input shaft 23.

[0054] The portion of the hole 156 where the shaft 27 fits is referred to as a fitting portion FP. The rotating shaft 15 is supported at two locations in the axial direction by the bearing 41 and the fitting portion FT. Thus, the bearing 41 does not need to be enlarged, and the deflection (tilting) of the rotating shaft 15 when torque acts on the rotating shaft 15 can be suppressed. As a result, the housing 14 having the bearing support portion 141 can be compactly configured.

[0055] The small diameter portion 152 of the rotating shaft 15 has a pulley support portion 152A to which the driven pulley 161 is mounted and a pulley support portion 152B to which the driven pulley 171 is mounted. The pulling force F1 is directed to the driven pulley 161 and the transmission belt 162. Fig.10 The pulling force F2 acts on the pulley support portion 152A in the direction of the arrow (forward). Fig.10 The direction of the arrow (rearward) acts on the pulley support portion 152B. The direction in which the tension F1 acts is substantially opposite to the direction in which the tension F2 acts. Thus, the tensions F1 and F2 acting on the rotating shaft 15 cancel each other out, and the radial load acting on the bearing 41 can be reduced.

[0056] Reference Figure 5 , 6 The assembly sequence of the drive unit 1 is described below. First, with the bearing 41 installed on the rotating shaft 15, insert the rotating shaft 15 into the bearing support portion 141 of the housing 14 from the right. Then, install the retaining spring 45 in the groove on the inner circumference of the bearing support portion 141, and install the rotating shaft 15 in the housing 14 in a rotatable manner. Next, after the washer 42, the driven pulley 171, the sleeve 43, and the driven pulley 161 are sequentially fitted into the outer circumference of the rotating shaft 15 from the left, the bolt 44 is threadedly engaged with the threaded hole 154 of the rotating shaft 15 to fix the washer 42, the driven pulley 171, the sleeve 43, and the driven pulley 161 to the rotating shaft 15. At this time, the transmission belts 162, 172 are pre-wound around the driven pulleys 161, 171, and the belts 162, 172 are pre-wound through the cutouts 148, 149 ( Figure 7B ) With the transmission belts 162 and 172 removed to the outside of the housing 14, the driven pulleys 161 and 171 are assembled to the rotating shaft 15.

[0057] Next, the pair of motors 11 and 12 are fixed to the motor support parts 132 and 133 ( Figure 8 ). Furthermore, by means of bolt 181 ( Figure 4 ) The support frame 13 is mounted on the flange portion 144 of the housing 14 ( Figure 7B ). At this time, the bracket 18 is installed at the same time. Next, after the transmission belts 162 and 172 are hung around the drive pulleys 111 and 121 of the motors 11 and 12, a predetermined tension is applied to the transmission belts 162 and 172. Finally, the end surface 146 ( Figure 4)The cover 140 is installed, and the assembly of the drive unit 1 is completed.

[0058] After the drive unit 1 is assembled, the base 143 of the housing 14 is fastened to the left end of the transmission housing 20 using bolts. At this time, the base 143 having a substantially L-shaped cross section is positioned on the transmission 2, so that Fig.10 As shown, the input shaft 23 and the rotating shaft 15 can be precisely located on the same axis. As a result, the input shaft 23 can be easily fitted into the bottomed hole 155 of the rotating shaft 15.

[0059] According to this embodiment, the following effects can be achieved.

[0060] (1) The vehicle drive device 100 includes: motors 11 and 12, which serve as driving sources for driving the vehicle 200; a transmission 2, which has an input shaft 23 to which torque is input, a speed change mechanism 21 for changing the speed of rotation of the input shaft 23, and a transmission case 20 for accommodating the input shaft 23 and the speed change mechanism 21; a rotating shaft 15, which extends coaxially with the input shaft 23 outside the transmission case 20 and is connected to the input shaft 23; and power transmission parts 16 and 17, which transmit the torque of the motors 11 and 12 to the rotating shaft 15, respectively. Figure 1 , 5 , 10). The motor 11 and the motor 12 are arranged at substantially symmetrical positions in the radial direction of the rotating shaft 15 with the rotating shaft 15 as the symmetry axis. Figure 4 ).

[0061] Thus, the torque of the multiple motors 11 and 12 is input to the input shaft 23 of the transmission 2 via the rotating shaft 15. Therefore, without using a large motor, the torque of the rear wheel 202 can be increased, and the vehicle drive device 100 can be miniaturized. In addition, the multiple motors 11 and 12 are arranged in approximately symmetrical positions across the rotating shaft 15, so the pulling forces F1 and F2 acting on the pulley support parts 152A and 152B of the rotating shaft 15 via the transmission belts 162 and 172 are in opposite directions and cancel each other out. Therefore, the radial load acting on the rotating shaft 15 can be reduced. Furthermore, for example, when a wheel is driven by a hub motor, the driving force of a single motor becomes the driving force of a single wheel. Therefore, it is possible that the driving force of the multiple motors as a whole cannot be transmitted to a single wheel, and sufficient driving force cannot be generated when the wheel is idling. In this regard, in the present embodiment, the driving force of the multiple motors 11 and 12 is input to the transmission 2, so that each wheel can generate sufficient driving force.

[0062] (2) The vehicle drive device 100 further includes a housing 14 mounted on the transmission housing 20 and covering the periphery of the rotating shaft 15, and a single bearing 41 ( Figure 5 , 6 The power transmission unit 16 includes an endless transmission belt 162 hung between a driving pulley 111 for outputting the torque of the motor 11 and a pulley support portion 152A (driven pulley 161) of the rotating shaft 15, and the power transmission unit 17 includes an endless transmission belt 172 hung between a driving pulley 121 for outputting the torque of the motor 12 and a pulley support portion 152B (driven pulley 171) of the rotating shaft 15. Figure 5 , 10 The pulley support portion 152A and the pulley support portion 152B are provided between the left end portion of the rotating shaft 15 and the bearing 41 so as to be separated from each other in the axial direction. Fig.10 ). Thus, the pulling forces F1 and F2 in opposite directions act on two axial locations of the rotating shaft 15 via the transmission belts 162 and 172. Therefore, the radial load acting on the bearing 41 can be reduced, and the bearing 41 and the housing 14 supporting the bearing 41 can be miniaturized.

[0063] (3) The transmission 2 further includes a pair of left and right bearings 25 and 26 for rotatably supporting the input shaft 23. Fig.10 The right end portion (fitting portion FP) of the rotating shaft 15 is fitted with the left end portion of the input shaft 23 in a manner capable of transmitting torque. Fig.10 ). Thus, the rotating shaft 15 is supported at two locations in the left-right direction by the fitting portion FP and the bearing 41. Therefore, it is not necessary to increase the size of the bearing 41, and the deflection of the rotating shaft 15 can be suppressed.

[0064] (4) The invention further comprises: a pair of left and right drive shafts 206 for transmitting the torque output from the transmission 2 to the left and right rear wheels 202, and a differential mechanism 3 for transmitting the torque output from the transmission 2 to the pair of left and right drive shafts 206. Figure 2 The motor 11 and the rotating shaft 15 are arranged in front of the driving shaft 206, and the motor 12 is arranged above the driving shaft 206 ( Figure 4 ). Thus, the vehicle drive device 100 is arranged close to the drive shaft 206, so that the ground load of the rear wheel 202 can be increased, and the grip of the tire can be improved.

[0065] (5) The height of the lower end of the motor 11 from the road surface is substantially the same as the height of the lower end of the differential mechanism 3 from the road surface. Figure 4 ). Thus, when one motor 12 is arranged above the drive shaft 206, the other motor 11 can be arranged at a substantially symmetrical position of the motor 12 with the rotation axis 15 as the symmetry axis, and a sufficient height of the motor 11 from the ground can be ensured.

[0066] This embodiment can be modified into various forms. Several modified examples are described below. In the above embodiment, a motor 12 (second motor) is arranged above the drive shaft 206, and another motor 11 (first motor) and the rotating shaft 15 are arranged in front of the drive shaft 206, but the first motor and the rotating shaft can also be arranged behind the drive shaft.

[0067] In the above embodiment, the transmission belt 162 (first belt-shaped member) is wound between the driving pulley 111 (first output portion) for outputting the torque of the motor 11 and the driven pulley 161 provided at the pulley support portion 152A (first portion) of the rotating shaft 15, and the transmission belt 172 (second belt-shaped member) is wound between the driving pulley 121 (second output portion) for outputting the torque of the motor 12 and the driven pulley 171 provided at the pulley support portion 152B (second portion) of the rotating shaft 15. Here, the annular belt-shaped member may be composed of a member other than the transmission belt (e.g., a chain).

[0068] In the above embodiment, a single bearing 41 for rotatably supporting the rotating shaft 15 is sandwiched between the housing 14 (housing portion) covering the periphery of the rotating shaft 15 and the rotating shaft 15, but the structure of the rotating shaft supporting portion is not limited to the above. In the above embodiment, a pair of left and right pulley supporting portions 152A, 152B are provided between the left end portion (one axial end portion) of the rotating shaft 15 and the bearing 41, but the configuration of the pulley supporting portion is not limited to the above. In the above embodiment, the input shaft 23 of the transmission 2 is rotatably supported on the transmission housing 20 by a pair of left and right bearings 25, 26, but the input shaft 23 may be rotatably supported by more input shaft supporting portions.

[0069] In the above embodiment, the holes 156 and 157 of the rotating shaft 15 and the shafts 27 and 28 of the input shaft 23 are engaged with each other by splines so as to transmit torque. That is, the right end (the other end in the axial direction) of the rotating shaft 15 and the left end (one end in the axial direction) of the input shaft 23 are engaged with each other, but the hole portion may be provided in the input shaft 23 and the shaft portion may be provided in the rotating shaft 15 so as to engage with each other. Therefore, the structure of the engagement portion FP where the one end in the axial direction of the input shaft 23 and the one end in the axial direction of the rotating shaft 15 are engaged is not limited to the above.

[0070] In the above embodiment, the vehicle drive device 100 is mounted on the bottom of the chassis 204 of the truck, and the rear wheels 202 are driven by the vehicle drive device 100, but the structure of the vehicle equipped with the vehicle drive device is not limited to the above. The vehicle drive device may drive the front wheels instead of the rear wheels of the vehicle. It is also possible to drive both the front wheels and the rear wheels. It is also possible to set a plurality of vehicle drive devices in the vehicle.

[0071] One or more of the above-described embodiments and modifications may be arbitrarily combined, and modifications may be combined with each other.

[0072] According to the present invention, it is not necessary to use a large motor, the driving force of the wheel can be increased, and the device can be miniaturized.

[0073] The present invention has been described above in conjunction with preferred embodiments, but it should be understood by those skilled in the art that various modifications and changes can be made without departing from the scope of the claims.

Claims

1. A vehicle driving device, characterized in that: have: A first motor (11) and a second motor (12) serving as driving sources for the vehicle (200); A transmission (2) comprising an input shaft (23) to which torque is input, a speed change mechanism (21) for changing the speed of rotation of the input shaft (23), and a transmission housing (20) for accommodating the input shaft (23) and the speed change mechanism (21); A rotating shaft (15) is outside the transmission housing (20), extends coaxially with the input shaft (23) and centered on the axis (CL1), and is connected to the input shaft (23); a first power transmission unit (16) for transmitting the torque of the first motor (11) to the rotating shaft (15); and a second power transmission unit (17) for transmitting the torque of the second motor (12) to the rotating shaft (15), The first motor (11) and the second motor (12) are arranged at substantially symmetrical positions with the rotation axis (15) as a symmetry axis.

2. The vehicle driving device according to claim 1, characterized in that: Also available: a housing portion (14) mounted on the transmission housing (20) and covering the periphery of the rotating shaft (15); and a single rotating shaft support portion (41) which is interposed between the housing portion (14) and the rotating shaft (15) and supports the rotating shaft (15) on the housing portion (14) in a rotatable manner; The first power transmission unit (16) includes an annular first belt-shaped member (162) wound between a first output unit (111) for outputting torque of the first motor (11) and a first portion (152A) of the rotating shaft (15). The second power transmission unit (17) includes an annular second belt-shaped member (172) wound between a second output unit (121) for outputting the torque of the second motor (12) and a second portion (152B) of the rotating shaft (15). The first portion (152A) and the second portion (152B) are provided between one axial end portion of the rotating shaft (15) and the rotating shaft support portion (41) and are separated from each other in the axial direction.

3. The vehicle driving device according to claim 2, characterized in that: The transmission (2) further comprises a plurality of axial input shaft support parts (25, 26) for rotatably supporting the input shaft (23). The other axial end portion of the rotating shaft (15) is fitted to the one axial end portion of the input shaft (23) in a torque-transmittable manner.

4. The vehicle driving device according to claim 2, characterized in that: A support frame (13) is also provided, wherein the support frame (13) is mounted on the end of the housing (14) and comprises a first motor support portion (132) for supporting the first motor (11) and a second motor support portion (133) for supporting the second motor (12).

5. The vehicle driving device according to claim 4, characterized in that: The first motor support portion (132) and the second motor support portion (133) are arranged at positions offset from each other in a direction along the axis (CL1).

6. The vehicle driving device according to claim 4, characterized in that: The invention also comprises a bracket portion (18), wherein the bracket portion (18) has a first mounting portion (182) mounted to the support frame portion (13) at one end thereof, and is arranged between the first motor (11) and the second motor (12). The bracket portion (18) has a second mounting portion (183) mounted on the vehicle body (204) at the other end.

7. The vehicle drive device according to any one of claims 1 to 6, characterized in that: Also available: a pair of left and right drive shafts (206) for transmitting the torque output from the transmission (2) to the left and right wheels (202); and a differential mechanism (3) for transmitting the torque output from the transmission (2) to the pair of left and right drive shafts (206), The first motor (11) and the rotating shaft (15) are arranged in front of or behind the driving shaft (206). The second motor (12) is arranged above the drive shaft (206).

8. The vehicle driving device according to claim 7, characterized in that: The first electric motor (11) is arranged so that the height of its lower end from the road surface is substantially the same as the height of the lower end of the differential mechanism (3) from the road surface.

9. The vehicle drive device according to any one of claims 1 to 6, characterized in that: An included angle between a pair of line segments extending from the axis (CL1) to the center of the first motor (11) and the center of the second motor (12) is greater than 135 degrees.

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