Drive device for electric vehicle

Abstract

To improve mountability of a power supply system such as a battery.SOLUTION: An electric vehicle includes an electric motor provided on a side member of the electric vehicle and having a first output shaft extending in a vehicle length direction, a transmission connected to the first output shaft and having a second output shaft that changes a driving force of the first output shaft, a differential connected to a suspension suspended from the side member, and a flexible joint coupling the second output shaft and an input shaft of the differential. The electric motor is disposed so as to be displaced from the differential in a vehicle width direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a drive device for an electric vehicle. [Background technology]

[0002] A drive source including an electric motor, a transmission, etc. of an electric vehicle is connected via a drive shaft to a driven mechanism including an axle, drive wheels, etc., and is arranged in the vehicle length direction of the electric vehicle. For example, Patent Document 1 discloses a technology in which the transmission and drive wheels, which are connected via a front joint and a rear joint of a propeller shaft, are arranged so as to be relatively offset in the vehicle height direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-109578 Summary of the Invention [Problem to be solved by the invention]

[0004] Here, depending on the model of the electric vehicle, it is conceivable that a larger battery will be installed due to factors such as the driving distance.

[0005] Therefore, an object of the present disclosure is to provide a drive device for an electric vehicle that improves the mountability of a power supply system such as a battery. [Means for solving the problem]

[0006] The present invention has been made to solve at least some of the above-mentioned problems, and can be realized as the following aspects or application examples.

[0007] The drive device of the electric vehicle according to this application example includes an electric motor provided on a side member of the electric vehicle and having a first output shaft extending in the vehicle length direction, a transmission connected to the first output shaft and having a second output shaft that changes the driving force of the first output shaft, a differential connected to a suspension suspended from the side member, and a flexible joint that connects the second output shaft and an input shaft of the differential, and is characterized in that the electric motor is positioned offset in the vehicle width direction relative to the differential.

[0008] According to this application example, the electric vehicle can arrange the transmission and differential closer to each other than in a configuration using a long connecting shaft such as a propeller shaft, thereby reducing the space occupied by the drive device including the electric motor, transmission, differential, etc. For example, the electric vehicle can arrange the electric motor and transmission further rearward, closer to the drive wheels, thereby increasing the space on the forward side in the vehicle length direction. Furthermore, the electric vehicle can also secure space on the opposite side of the electric motor in the vehicle width direction by arranging the electric motor offset from the differential.

[0009] Therefore, according to the present disclosure, it is possible to provide a drive device for an electric vehicle that improves the mountability of a power supply system such as a battery. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a plan view showing a part of the configuration of a chassis frame, a drive device, and the like of an electric vehicle. [Figure 2] 2 is a cross-sectional view of the electric vehicle shown in FIG. 1 taken along line II-II. [Figure 3] FIG. 3 is a cross-sectional view of the flexible joint shown in FIG. 1 taken along line III-III. DETAILED DESCRIPTION OF THE INVENTION

[0011] Next, one embodiment of a configuration according to the present disclosure will be described with reference to FIGS. 1 to 3 as appropriate.

[0012] Fig. 1 is a plan view showing a part of the configuration of the chassis frame 2, the drive unit 10, etc. at the rear side of the electric vehicle 1. Fig. 2 is a cross-sectional view taken along line II-II of the electric vehicle in Fig. 1. In the following description, the left side of Fig. 1 will be referred to as the front of the electric vehicle 1 and the opposite side as the rear, and the lower side of Fig. 1 will be referred to as the left of the electric vehicle 1 and the opposite side as the right. Furthermore, the upper side of Fig. 2 will be referred to as the top of the electric vehicle 1 and the opposite side as the bottom.

[0013] The electric vehicle 1 includes a chassis frame 2, a power supply system 3, a drive system 4, and a wheel mechanism 5. The power supply system 3, the drive system 4, and the wheel mechanism 5 constitute a drive unit 10 of the electric vehicle 1. The chassis frame 2 in this embodiment is a ladder frame and includes a pair of left and right side members 2a and a cross member 2b. The side members 2a extend in the fore-and-aft direction (vehicle length direction) of the electric vehicle 1 and are arranged parallel to each other. The cross member 2b extends in the left-and-right direction (vehicle width direction) of the electric vehicle 1 and connects the pair of left and right side members 2a. The chassis frame 2 supports a cab (not shown), the power supply system 3, the drive system 4, and other heavy objects.

[0014] The cab is a structure including a driver's seat (not shown) and is provided on the upper front side of the chassis frame 2. The power supply system 3 includes a battery 31 and an inverter (not shown) connected to the output of the battery 31. The electric vehicle 1 in Fig. 1 includes two batteries 31 in front of the electric motor 41 in the vehicle length direction D1.

[0015] The drivetrain 4 includes an electric motor 41, a transmission 42 (power transmission section), a flexible joint 43, a differential 44, etc. The electric motor 41 includes a motor. The electric motor 41 generates a driving force required for running the electric vehicle 1 by receiving AC power supplied from the battery 31 via an inverter (not shown). The electric motor 41 is provided on a side member 2a of the electric vehicle 1. The electric motor 41 is disposed offset in the vehicle width direction D2 with respect to the differential 44. In the example of FIG. 1, the electric motor 41 is disposed on the right side of the electric vehicle 1 with respect to the differential 44. The electric motor 41 also has a first output shaft P1 extending in the vehicle length direction D1.

[0016] The transmission 42 includes a plurality of gears and functions as a reducer that reduces the rotational driving force supplied from the electric motor 41. The transmission 42 is connected to the first output shaft P1 of the electric motor 41, and has a second output shaft P2 that changes the speed (reduces) of the driving force of the first output shaft P1 inside the transmission 42 and outputs the rotational driving force.

[0017] The flexible joint 43 connects the second output shaft P2 of the transmission 42 and the input shaft P3 of the differential 44 together.

[0018] The differential 44 distributes the rotational driving force input from the transmission 42 to the left and right drive wheels 5a, 5b (5), which are the rear wheels. That is, the drivetrain 4 changes the rotational driving force of the electric motor 41 to a rotational speed suitable for driving the electric vehicle 1 via the transmission 42 and the differential 44 and transmits it to the rear axles 45a, 45b (45). As a result, the drivetrain 4 rotates the drive wheels 5a, 5b (5) via the rear axles 45a, 45b (45), causing the electric vehicle 1 to drive. The differential 44 and the rear axles 45a, 45b (45) are connected to a suspension (e.g., leaf spring) 6 suspended from the side member 2a.

[0019] Fig. 3 is a cross-sectional view of the flexible joint 43 taken along the line III-III of Fig. 1. Note that the configuration of the flexible joint 43 in Fig. 3 is an example and is not limited to this.

[0020] The flexible joint 43 has joint bodies 431 whose general shape is symmetrical about the axes (P2, P3), and a connecting member 432 that connects the joint bodies 431 together. The joint body 431 is formed in a generally plate-like shape and has a bottomed bearing portion 431a that is recessed in a concave shape on its outer surface. The connecting member 432 is curved in a U-shape in cross section and is formed in a generally rotationally symmetric manner about the axis. Therefore, the connecting member 432 is formed in a generally annular shape that is recessed in a concave shape around the outer periphery.

[0021] In the flexible joint 43, a joint body 431 and a coupling member 432 are connected in an annular shape by fastening with a screw member or the like on each of the second output shaft P2 side and the input shaft P3 side. The coupling members 432 are also connected in an annular shape by fastening with a screw member or the like.

[0022] The flexible joint 43 houses the second output shaft P2 and the input shaft P3 in the bearing portion 431a, and connects them while arranging them facing each other on approximately the same axis. The second output shaft P2 and the bearing portion 431a (as well as the input shaft P3 and the bearing portion 431a) are connected, for example, in a fitted, fastened, or engaged state.

[0023] The flexible joint 43 transmits the rotational driving force (torque) of the electric motor 41 to the input shaft P3 of the differential 44 while allowing relative displacement between the second output shaft P2 and the input shaft P3 due to the bending of the connecting member 432. The allowable relative displacement includes, for example, relative angular displacement up to a preset range and displacement in the axial direction.

[0024] Therefore, even if the electric motor 41 and the transmission 42 are fixedly provided on the side member 2a side and the differential 44 is connected to the side of the suspension (leaf spring) 6 suspended from the side member 2a, the electric vehicle 1 can transmit the rotational driving force from the electric motor 41 side to the differential 44 side while allowing relative displacement between the second output shaft P2 and the input shaft P3.

[0025] The drive device for an electric vehicle according to this embodiment has been described above. The drive device includes an electric motor 41 provided on a side member 2a of the electric vehicle 1 and having a first output shaft P1 extending in the vehicle length direction D1, a transmission 42 connected to the first output shaft P1 and having a second output shaft P2 that changes the speed of the driving force of the first output shaft P1, a differential 44 connected to a suspension (leaf spring) 6 suspended from the side member 2a, and a flexible joint 43 that connects the second output shaft P2 to an input shaft P3 of the differential 44. The electric motor 41 is positioned offset in the vehicle width direction D2 with respect to the differential 44.

[0026] Therefore, in the electric vehicle 1, the transmission 42 and the differential 44 can be disposed close to each other, thereby increasing the space between the electric motor 41 and the transmission 42. For example, in the electric vehicle 1, the electric motor 41 and the transmission 42 can be disposed further rearward, closer to the drive wheels 5a and 5b, thereby increasing the space on the forward side in the vehicle length direction D1. Furthermore, in the electric vehicle 1, by displacing the electric motor 41 in the vehicle width direction D2 relative to the differential 44, space can also be secured on the opposite side of the electric motor 41 in the vehicle width direction D2. This improves the mountability of the power supply system 3, such as the battery 31.

[0027] The electric vehicle 1 of this embodiment is provided with two batteries 31 in the vehicle length direction D1 in front of the electric motor 41. Therefore, the drive device 10 of the electric vehicle 1 of this embodiment can arrange the batteries 31, which are heavy objects, near the center of gravity of the electric vehicle 1, and therefore can ensure an area for mounting the large batteries 31 while maintaining the weight balance of the electric vehicle 1.

[0028] Although the description of the embodiment of the present invention has been completed above, the aspects of the present invention are not limited to this embodiment.

[0029] For example, in the present embodiment, the electric motor 41 is disposed on the right side of the electric vehicle 1 relative to the differential 44, but may be disposed on the left side of the electric vehicle 1.

[0030] In addition, in this embodiment, the output shafts (P1, P2) of the electric motor 41 and the transmission 42 and the input shaft P3 of the differential 44 are arranged parallel to each other, but the output shafts (P1, P2) may be arranged inclined to the right or left of the electric vehicle 1 with respect to the input shaft P3. In this case, the electric motor 41 and the transmission 42 are arranged inclined to either the left or right with respect to the differential 44.

[0031] In addition, in this embodiment, the electric motor 41 is disposed offset in the vehicle width direction D2 with respect to the differential 44, but this is not limiting, and for example, in a case where a flexible joint 43 is provided between the electric motor 41 and the differential 44, the electric motor 41 may be configured to be disposed linearly without being offset in the vehicle width direction D2 with respect to the differential 44. In this case, for example, in FIG. 1, the output shafts (P1, P2) and the input shaft P3 are disposed linearly without being offset in the vehicle width direction D2.

[0032] Furthermore, when a flexible joint 43 is provided between the electric motor 41 and the differential 44, it may be offset in the vehicle height direction D3. In this case, for example, in FIG. 2, the input shaft P3 is offset in the vehicle height direction D3 (upper or lower) with respect to the output shafts (P1, P2). [Explanation of symbols]

[0033] 1 Electric vehicles 2 Chassis frame 2a Side member 2b Cross member 3 Power system 4. Drivetrain 5 Wheel mechanism 5a, 5b Drive wheels 6 Suspension (leaf spring) 10 Drive unit 31 Battery 41 Electric motor 42 Transmission 43 Flexible joint 44 Differential 45a, 45b rear axle 431 Joint body 431a Bearing section 432 Connecting member D1 Vehicle length direction D2 Vehicle width direction D3 Vehicle height direction P1 First output shaft P2 Second output shaft P3 input shaft

Claims

[Claim 1] an electric motor provided on a side member of the electric vehicle and having a first output shaft extending in a vehicle length direction; a transmission having a second output shaft connected to the first output shaft and adapted to change the speed of the driving force of the first output shaft; a differential connected to a suspension suspended from the side member; a flexible coupling connecting the second output shaft and an input shaft of the differential; Equipped with A drive device for an electric vehicle, wherein the electric motor is disposed offset in the vehicle width direction relative to the differential.

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