JP4379867B2 - Power unit for electric vehicles - Google Patents

Description

  The present invention relates to a power unit for an electric vehicle.

As a drive shaft constituting a part of a conventional power unit, a drive shaft connected to a transaxle is known (for example, see Patent Document 1).
JP-A-10-119505

FIG. 1 of Patent Document 1 will be described with reference to FIG. In addition, the code | symbol was reassigned.
FIG. 5 is a cross-sectional view showing a conventional drive shaft mounting structure. A final reduction gear 202 is provided in a transaxle 201, and a casing 204 is rotatably attached to a bearing 203 provided in the final reduction gear 202. A shaft portion 208 constituting a part of the connecting shaft 207 is attached to the gear 206 arranged in FIG. 2, and the intermediate shaft 212 is connected to a cylindrical outer race 211 protruding from the transaxle 201 of the connecting shaft 207. The intermediate shaft 212 is connected to a wheel (not shown).

  The intermediate shaft 212 has a triport 213 splined to the tip, and the triport 213 forms three cylindrical trunnions 214 projecting in the radial direction on the outer periphery. The trunnions 214 are respectively provided with rollers via bearings 216. 217 is rotatably attached. The rollers 217 slide in three axially extending grooves provided in the hollow portion of the outer race 211 described above.

  The connecting shaft 207 and the intermediate shaft 212 described above are components provided in the drive shaft 218. The outer race 211, the intermediate shaft 212, the triport 213, the trunnion 214, the bearing 216, and the roller 217 described above are components constituting a constant velocity joint, that is, an inboard joint.

  The transaxle 201 and the wheel are connected by the drive shaft 218 described above. For example, when the distance between the transaxle 201 and the wheel is short, the entire length of the drive shaft 218 is shortened, and the maximum inboard joint of the drive shaft 218 is increased. Since the bending angle is determined, the vertical stroke amount of the wheel is reduced, which affects the riding comfort of the vehicle.

  Therefore, if the total length of the drive shaft 218 is increased in order to increase the vertical stroke amount of the wheel, the distance between the transaxle 201 and the wheel increases, the distance between the left and right wheels, so-called tread increases, and the vehicle width Increases the size of the vehicle.

  If the total length of the drive shaft 218 is increased while maintaining the transaxle 201 and the wheel at a predetermined distance, for example, if the protrusion amount of the outer race 211 from the transaxle 201 can be reduced and the total length of the drive shaft 218 can be increased. A large amount of vertical stroke of the wheel can be secured.

  Further, in recent years, it has been required to further increase the size of the interior of a vehicle (for example, a passenger compartment, a luggage compartment, etc.) among the limited vehicle outer dimensions, and the power unit and the power transmission device itself can be made more compact, It has become necessary to dispose the power transmission device on the outside of the vehicle body. If such a countermeasure can be implemented in a state where the entire length of the drive shaft 218 is secured, the above-described wheel vertical stroke amount can be secured, and the transaxle 201 can be moved further outward from the vehicle body, thereby increasing the space inside the vehicle.

  An object of the present invention is to improve the power unit for an electric vehicle, thereby ensuring the vertical stroke amount of the wheel, reducing the size of the power transmission device, and further expanding the space in the vehicle.

The invention according to claim 1 is an electric vehicle in which a power unit for driving wheels is attached to a side frame, and the power unit is provided in the electric motor, a speed reduction mechanism connected to a rotating shaft of the electric motor, and the speed reduction mechanism. In a power unit for an electric vehicle comprising a drive shaft connected to the final gear and a case for housing these electric motors, the entire speed reduction mechanism, and a part of the drive shaft , the final gear is arranged in a direction perpendicular to the axis of rotation. The constant velocity joint provided at one end of the drive shaft is disposed inside the final gear, and the power unit is disposed below the side frame.

By disposing the constant velocity joint inside the final gear, the amount of protrusion of the constant velocity joint to the side of the vehicle is reduced. Further, when the power units are arranged below the left and right side frames, the distance between the left and right power units can be further increased.

In the invention according to claim 1, the final gear is arranged so as to be aligned in a direction perpendicular to the axis of the rotation shaft , and the constant velocity joint is arranged inside the final gear, so that the constant velocity joint protrudes toward the vehicle side. The power transmission unit comprising the power unit, specifically the speed reduction mechanism and the drive shaft, can be made compact.

Also, when placing the power unit to each of the lower left and right side frames, it is possible to increase the distance between the left and right of the power unit, it is possible to form a large space between the left and right of the power unit. Therefore, the vehicle interior space can be expanded to the space side, and a large vehicle interior space can be secured.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.
FIG. 1 is an explanatory view of an electric vehicle equipped with a power unit according to the present invention. The electric vehicle 10 has a battery 13 disposed below the front seat 11, more specifically, below the floor panel 12, and between the left and right front wheels 14. A power unit 16 is arranged, and the front wheel 14 is driven by supplying power from the battery 13 to the power unit 16, specifically an electric motor described later. Reference numeral 18 denotes a rear seat, 21 denotes a passenger compartment, and 22 denotes left and right rear wheels.

  FIG. 2 is a plan view for explaining the power unit according to the present invention (the arrow (FRONT) represents the front of the vehicle. The same applies hereinafter), and a pair of left and right front side frames 31 and 32 are arranged at the front portion of the electric vehicle 10. The left power unit 33 and the right power unit 34 constituting the power unit 16 are attached to the lower portions of the front side frames 31 and 32, and the left and right front wheels 14 and 14 are connected to the power units 33 and 34, respectively.

  Here, 36 and 37 are floor frames attached to the center of the floor panel 12 in the vehicle width direction, 41 and 42 are side sills provided at both edges of the floor panel 12 in the vehicle width direction, and 43 and 44 are capable of moving the front wheel 14 up and down. Suspension arms 46 attached to the front side frames 31 and 32 for supporting the front side frames 31 and 32, respectively, are bumper beams passed to the front ends of the front side frames 31 and 32, respectively.

  The left power unit 33 includes a power unit main body 51 and a drive shaft 52 extending from the power unit main body 51 substantially to the side of the vehicle body. The front end of the drive shaft 52 is connected to the front wheel 14 via a hub (not shown).

The drive shaft 52 is provided with constant velocity joints 54 and 55 at each end, the constant velocity joint 54 on the power unit main body 51 side is an inboard joint, and the constant velocity joint 55 on the front wheel 14 side is It is also called an outboard joint.
The right power unit 34 has the same basic structure as the left power unit 33 described above, and a detailed description thereof will be omitted.

  FIG. 3 is a cross-sectional view showing a power unit according to the present invention. The left power unit 33 includes an electric motor 61, a power transmission device 63 connected to a rotating shaft 62 of the electric motor 61, the whole of the electric motor 61, and The power transmission device 63 includes a drive case 64 that houses a part of the power transmission device 63. The power transmission device 63 includes a speed reduction mechanism 66 that includes a plurality of gears and support shafts, and the drive shaft 52 that is connected to the speed reduction mechanism 66. Consists of. Reference numerals 71, 72, 73, and 74 denote a case main body (a member indicated by a thick line), a first case cover, a second case cover, and a third case cover that constitute the drive case 64.

The electric motor 61 includes a stator 76 attached to the case main body 71 and a rotor 77 disposed inside the stator 76. The stator 76 includes a coil 78, and the rotor 77 is a first bearing attached to the case main body 71. A rotary shaft 84 rotatably supported by a second bearing 83 attached to the first case cover 72 via a support shaft 82, and a plurality of permanent magnets supported by flange members 86 and 87 attached to the rotary shaft 84. 88.
The coil 78 is energized from the outside via the bus bar 91 and the connection fitting 92. Reference numeral 93 denotes a connection connector.

The support shaft 82 is a member in which a screw 95 is formed at the end, and is attached to the first case cover 72 by screwing a nut 96 into the male screw 95.
The rotation shaft 84 is a member in which a tooth portion 97 is formed at the tip portion.

  The speed reduction mechanism 66 is rotatably attached to the first support shaft 111 held by the case body 71 and the second case cover 73, and the second case cover 73 via the bearing 112, and the bearing 113 is attached to the third case cover 74. A second support shaft 114 that is rotatably mounted via a bearing, and a gear support as a support shaft that is rotatably mounted to the case body 71 via a bearing 116 and is also rotatably mounted to the third case cover 74 via a bearing 117. A cylindrical body 118, a first gear 122 that is rotatably attached to the first support shaft 111 via a plurality of bearings 121 and meshed with a tooth portion 97 of the rotation shaft 84, and one end portion side of the second support shaft 114. A second gear 123 that is spline-coupled and meshed with the first gear 122, and a third molded integrally with the second support shaft 114 on the other end side. And Ya 124, and a fourth gear 128 serving as a final gear which is meshed with the third gear 124 is attached by a plurality of bolts 127 to a flange portion 126 which projects integrally from the outer circumferential surface of the gear support cylinder 118. Reference numeral 129 denotes a nut for attaching the second support shaft 114 to the bearing 112.

  The constant velocity joint 54 of the drive shaft 52 is coupled to a large-diameter hole 131 and a small-diameter hole 132 formed in the gear support cylinder 118, more specifically, a housing 133 that is spline-coupled, and a large-diameter hole 131 of the housing 133. The three rollers 136 that slide in the three grooves 134, the spider 138 integrally including a shaft 137 that rotatably supports these rollers 136, and a shaft that is splined at the end to the spider 138. 141 and a sliding triport joint comprising a rubber boot 142 that covers the housing 133 and the shaft 141 in order to prevent dust from entering the housing 133. Reference numerals 144 and 145 denote bands for fixing the rubber boot 142.

4A and 4B are cross-sectional views for comparing the arrangement of constant velocity joints in the power transmission device. Note that in both (a) and (b), the vertical direction in the figure is the horizontal direction of the vehicle (the vehicle width direction).
The power transmission device 230 of the comparative example shown in (a) includes a final reduction gear 231 and drive shafts 232 and 233 connected to the left and right of the final reduction gear 231. The front ends of these drive shafts 232 and 233 are connected to the left and right wheels.

  The final reduction gear 231 includes a transmission shaft 235 connected to the drive source side, a reduction small gear 236 formed integrally with the transmission shaft 235, and a reduction large gear 237 that meshes with the reduction small gear 236 (the portion indicated by a thick line) And a differential device 238 that supports the large reduction gear 237 and a case 239 (divided into a left case 239a and a right case 239b). Reference numeral 242 denotes a bearing attached to the left case 239a to support the transmission shaft 235.

  The differential device 238 includes a differential case 244 that supports the reduction large gear 237, a pin 245 that is inserted through the differential case 244, and a pin 245 that is rotatably attached to the pin 245. The differential small gears 247 and 247 accommodated in the portion 246 and the differential large gears 248 and 248 that mesh with the differential small gears 247 and 247 and accommodated in the hollow portion 246 are included.

  The differential case 244 is rotatably supported by a bearing (tapered roller bearing) 251 attached to the left case 239a and a bearing (tapered roller bearing) 252 attached to the right case 239b, and projects integrally from the outer peripheral surface. This is a component in which a large reduction gear 237 is attached to a flange portion 253 that has been made by a plurality of bolts 254. A plurality of symbols 256 are dust seals that prevent dust from entering the case 239.

  The drive shaft 232 includes a constant velocity joint 258 (an inboard joint) at one end, and the shaft portion 262 of the housing 261 (the outline is a portion indicated by a thick line) constituting the constant velocity joint 258 is described above. This is a member that is spline-coupled to the differential large gear 248. The drive shaft 233 has the same structure as the drive shaft 232 described above, and a detailed description thereof is omitted. Reference numerals 264, 265, 266, and 267 denote rollers, spiders, shafts, and rubber boots.

  In the power transmission device 230 of the above-described comparative example, the constant velocity joints 258 of the drive shafts 232 and 233, specifically, the housing 261 protrude in the left-right direction of the vehicle. Here, the distances from the center of the tooth width of the reduction large gear 237, which is the final gear, to the end of each housing 261 are denoted by L1 and L2.

  In the power transmission device 63 of the embodiment shown in (b), the constant velocity joint 54 of the drive shaft 52, specifically, the housing 133 (the part indicated by the bold line) is the fourth gear 128 which is a final gear. Because it is located inside the vehicle, it does not protrude in the left direction of the vehicle. Here, if the distance from the center of the tooth width of the fourth gear 128 to the end of the housing 133 is L3, L3 <L1 and L3 <L2 are satisfied with respect to the distances L1 and L2 shown in FIG.

  Therefore, the power transmission device 63 of the present embodiment can reduce the outer dimension in the vehicle width direction as compared with the power transmission device 230 of the comparative example shown in FIG. Can be made compact.

  As described above with reference to FIGS. 2 and 3, the present invention is an electric vehicle in which power units (the left power unit 33 and the right power unit 34) for driving the front wheels 14 as wheels are attached to the left and right front side frames 31 and 32, respectively. 10, the power units 33 and 34 are connected to an electric motor 61, a speed reduction mechanism 66 connected to the rotating shaft 62 of the electric motor 61, and a drive shaft 52 connected to a fourth gear 128 provided in the speed reduction mechanism 66. The electric motor 61, the entire speed reduction mechanism 66, and a drive case 64 that houses a part of the drive shaft 52, and a constant velocity joint 54 provided at one end of the drive shaft 52 inside the fourth gear 128. The power units 33, 3 are arranged below the front side frames 31, 32, respectively. Characterized in that a.

  By disposing the constant velocity joint 54 inside the fourth gear 128, the amount of protrusion of the constant velocity joint 54 toward the vehicle side can be reduced, and the power units 33 and 34, more specifically, the speed reduction mechanism 66 and the drive shaft 52 can be reduced. The power transmission device 63 can be made compact.

  Further, by arranging the power units 33 and 34 below the front side frames 31 and 32, the distance between the left and right power units 33 and 34 can be increased, and a large space 150 is provided between the left and right power units 33 and 34. Can be formed. Therefore, a vehicle interior space, for example, the passenger compartment 21 (see FIG. 1) can be expanded toward the space 150, and a large passenger compartment 21 can be secured.

  In the present embodiment, the power unit is mounted on the electric vehicle. However, the present invention is not limited thereto, and the power unit may be mounted on a fuel cell vehicle including a fuel cell instead of the battery.

  The power unit of the present invention is suitable for electric vehicles and fuel cell vehicles.

It is explanatory drawing of the electric vehicle carrying the power unit which concerns on this invention. It is a top view explaining the power unit concerning the present invention. It is sectional drawing which shows the power unit which concerns on this invention. It is sectional drawing which compares arrangement | positioning of the constant velocity joint in a power transmission device. It is sectional drawing which shows the conventional drive shaft attachment structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Electric vehicle, 14 ... Wheel (front wheel) 31, 32 ... Side frame ( front side frame ) 33, 34 ... Power unit (left power unit, right power unit), 52 ... Drive shaft, 54, 55 ... Constant velocity joint, DESCRIPTION OF SYMBOLS 61 ... Electric motor, 62 ... Rotating shaft, 63 ... Power transmission device, 64 ... Case (drive case), 66 ... Deceleration mechanism, 128 ... Final gear (4th gear).

Claims (1)

An electric vehicle having a power unit for driving wheels on a side frame,
The power unit includes an electric motor, a speed reduction mechanism connected to the rotating shaft of the electric motor, a drive shaft connected to a final gear provided in the speed reduction mechanism, the electric motor, the whole speed reduction mechanism, and one of the drive shafts. In a power unit for an electric vehicle comprising a case for storing a part,
The final gear is arranged so as to be aligned in a direction perpendicular to the axis of the rotation shaft, a constant velocity joint provided at one end of the drive shaft is arranged inside the final gear, and the power unit is arranged below the side frame. A power unit for an electric vehicle characterized by that.

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