Electric vehicle

Abstract

To provide an electric vehicle capable of obtaining both an improved rigidity and vibration damping effect for a case while maintaining a space-saving structure.SOLUTION: In the present invention, an oil reservoir is formed between a first partition that separates a drive chamber and an inverter chamber, and a second partition that is provided on the drive chamber side of the first partition and separates the drive chamber and the inverter chamber, and a through hole is provided vertically above the second partition to allow oil scooped up by gears provided in a power transmission device to flow into an oil reservoir. This makes it possible to utilize existing oil to increase the rigidity of the case by the adjacent partitions and the oil stored in the oil reservoir, thereby obtaining a vibration-damping effect. Therefore, it is possible to obtain both the effects of improving the rigidity of the case and the vibration damping effect while maintaining the space-saving structure.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an electric vehicle including a case that integrally houses an electric motor, a power transmission device, and an inverter. [Background technology]

[0002] There is a well-known electric vehicle that includes an electric motor, a power transmission device that transmits the power of the electric motor to drive wheels, an inverter that controls the electric motor, and a case that integrally houses the electric motor, the power transmission device, and the inverter. For example, a drive unit is described in Patent Document 1. Patent Document 1 discloses that the case includes a motor case that houses a rotating electric machine, and an inverter case that houses an inverter and is disposed adjacent to the motor case. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-44922 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a case that houses a drive unit including an electric motor and a power transmission device and an inverter as an integrated unit, it is possible to design the partition wall that separates the drive chamber that houses the drive unit from the inverter chamber that houses the inverter with a minimum of rigidity in order to save space. However, since the case deformation and vibration caused by the torque from the drive chamber act excessively on the inverter, measures must be taken as necessary.

[0005] The present invention has been made against the background of the above circumstances, and its object is to provide an electric vehicle that can obtain both the effects of improved case rigidity and vibration damping while maintaining a space-saving structure. [Means for solving the problem]

[0006] The gist of a first aspect of the present invention is an electric vehicle including: (a) an electric motor, a power transmission device that transmits power of the electric motor to drive wheels, an inverter that controls the electric motor, and a case that integrally houses the electric motor, the power transmission device, and the inverter, (b) the case includes a drive chamber that houses a drive unit including the electric motor and the power transmission device, and a portion vertically below a gear of the power transmission device is immersed in oil when the case is mounted on the electric vehicle; and (c) a drive chamber that houses the inverter disposed horizontally adjacent to the drive chamber when the case is mounted on the electric vehicle. (d) an inverter chamber that accommodates a motor; (d) a first partition that separates the drive chamber and the inverter chamber; (e) a second partition that is provided on the drive chamber side of the first partition and separates the drive chamber and the inverter chamber; (f) an oil reservoir formed between the first partition and the second partition for storing the oil scooped up by a gear provided in the power transmission device; and (g) a through hole that is provided vertically above the second partition and allows the oil scooped up by the gear provided in the power transmission device to flow into the oil reservoir when the power transmission device is mounted on the electric vehicle. Effect of the Invention

[0007] According to the first aspect of the present invention, an oil reservoir is formed between a first partition wall separating the drive chamber and the inverter chamber, and a second partition wall separating the drive chamber and the inverter chamber, which is provided on the drive chamber side of the first partition wall, and a through hole is provided vertically above the second partition wall, through which oil scooped up by a gear of the power transmission device flows into the oil reservoir. This makes it possible to increase the rigidity of the case by utilizing the existing oil, using the adjacent partition wall and the oil stored in the oil reservoir, and to obtain a vibration-proofing effect. Therefore, it is possible to obtain both the effects of improving the rigidity of the case and the vibration-proofing effect while maintaining the space-saving structure. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating an example of an electric vehicle to which the present invention is applied; [Diagram 2] FIG. 2 is a diagram illustrating an example of a schematic configuration of a drive unit. [Diagram 3] FIG. 3 is a diagram for explaining an example of a schematic configuration of a drive unit, which is an embodiment different from that of FIG. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. EXAMPLES

[0010] Fig. 1 is a diagram illustrating an example of an electric vehicle 10 to which the present invention is applied. Fig. 1(a) is a diagram illustrating an example of a schematic configuration of the electric vehicle 10. In Fig. 1(a), the electric vehicle 10 is an electric car equipped with an electric motor MG that functions as a power source. The electric vehicle 10 also includes drive wheels 12 and a power transmission device 14 provided in a power transmission path between the electric motor MG and the drive wheels 12.

[0011] The electric motor MG is a known rotating electric machine having a function as a motor that generates mechanical power from electric power and a function as a generator that generates electric power from mechanical power, and is a so-called motor generator.

[0012] The power transmission device 14 includes a drive gear 16, a driven gear 18, a driven shaft 20, a final gear 22, a differential gear 24, a drive shaft 26, and the like.

[0013] The drive gear 16 is connected to a rotor shaft of the electric motor MG, and the electric motor MG is connected to the drive gear 16 so as to be capable of transmitting power. The driven gear 18 has a larger diameter than the drive gear 16 and is engaged with the drive gear 16. The driven shaft 20 fixes the driven gear 18 and a final gear 22 so that they cannot rotate relative to each other. The final gear 22 has a smaller diameter than the driven gear 18 and is engaged with a differential ring gear 24a of the differential gear 24. The drive shaft 26 is connected to the differential gear 24.

[0014] The power transmission device 14 configured in this manner transmits the power output from the electric motor MG to the driven gear 18 via the drive gear 16. The power transmission device 14 transmits the power transmitted to the driven gear 18 to the driving wheels 12 sequentially via the driven shaft 20, the final gear 22, the differential gear 24, the drive shaft 26, etc.

[0015] The power transmission device 14 has a first axis CL1, a second axis CL2, and a third axis CL3. These three axes CL1, CL2, and CL3 are parallel to one another. The first axis CL1 is a rotation axis of the electric motor MG and the drive gear 16. The second axis CL2 is a rotation axis of the driven gear 18, the driven shaft 20, and the final gear 22. The third axis CL3 is a rotation axis of the differential gear 24 and the drive shaft 26.

[0016] 1(b) is a diagram illustrating an example of an electrical configuration of the electric vehicle 10, particularly an electrical configuration related to control of the electric motor MG. In FIG. 1(b), the electric vehicle 10 includes a high-voltage battery 30 and an inverter 32.

[0017] The high-voltage battery 30 is a chargeable and dischargeable DC power source, such as a secondary battery such as a nickel-metal hydride secondary battery or a lithium-ion battery. The high-voltage battery 30 is connected to an inverter 32. Stored electric power is supplied from the high-voltage battery 30 to the electric motor MG via the inverter 32. In addition, electric power generated by regenerative control of the electric motor MG is supplied to the high-voltage battery 30 via the inverter 32.

[0018] The inverter 32 is operated by a command from a motor control device (not shown). The inverter 32 is a power control device that controls the power exchanged between the high-voltage battery 30 and the motor MG, and is an inverter assembly for motor control that controls the motor MG. The inverter 32 includes an MG power module 34 and the like. The inverter 32 converts a direct current from the high-voltage battery 30 into an alternating current for driving the motor MG by driving the MG power module 34 on and off as a switching element. The inverter 32 also converts an alternating current generated by the motor MG by regenerative braking into a direct current.

[0019] FIG. 2 is a diagram illustrating an example of a schematic configuration of a drive unit 50 housed in a case 40 provided in an electric vehicle 10. FIG. 2 is a side view of the electric vehicle 10 from the left side. In FIG. 2, the case 40 is a non-rotatable case that is a non-rotating member attached to a vehicle body, and houses an electric motor MG, a power transmission device 14 (excluding a drive shaft 26), and an inverter 32 integrally. The drive unit 50 is a unit in which a transaxle 52 and an inverter 32 are integrated, that is, an electromechanical integrated unit. In other words, the transaxle 52 and the inverter 32 are housed in the same case 40 as the drive unit 50. The transaxle 52 is a drive device including the power transmission device 14 and the electric motor MG. The vertical direction and the forward and reverse directions in the figure indicate the directions in a mounted state in the electric vehicle 10. The vehicle width direction (see FIG. 3) is a horizontal direction perpendicular to the forward and backward travel direction of the electric vehicle 10, and is parallel to the axial directions of the first axis CL1, the second axis CL2, and the third axis CL3.

[0020] 2, when transaxle 52 is mounted on electric vehicle 10, first axis CL1, second axis CL2, and third axis CL3 are arranged parallel to the vehicle width direction of electric vehicle 10. When transaxle 52 is mounted on electric vehicle 10, the positions of first axis CL1, second axis CL2, and third axis CL3 are, from top to bottom in the vertical direction, electric motor MG, differential gear 24, and driven shaft 20, and, from front to rear in the forward / reverse direction, electric motor MG, driven shaft 20, and differential gear 24. When inverter 32 is mounted on electric vehicle 10, inverter 32 is arranged at a position overlapping transaxle 52 when viewed in the horizontal direction.

[0021] The case 40 includes a drive chamber Rpu, an inverter chamber Rinv, a first partition wall 60 and a second partition wall 62.

[0022] The drive chamber Rpu is a space within the case 40 that houses the transaxle 52 (excluding the drive shaft 26). In the drive chamber Rpu, a vertically lower portion of a gear, such as the differential ring gear 24a, included in the power transmission device 14 is immersed in oil FLD when the drive chamber Rpu is mounted on the electric vehicle 10. In other words, a vertically lower portion of the differential ring gear 24a is immersed in an oil reservoir Roil that is provided at the bottom of the drive chamber Rpu and that accumulates the oil FLD. The inverter chamber Rinv is a space within the case 40 that houses the inverter 32. For example, the board of the inverter 32 is fastened to the inverter chamber Rinv. When the drive chamber Rinv is mounted on the electric vehicle 10, the inverter chamber Rinv is disposed adjacent to the drive chamber Rpu in the horizontal direction.

[0023] The first partition 60 and the second partition 62 are partitions that separate the drive chamber Rpu and the inverter chamber Rinv. In the case 40, the wall that separates the drive chamber Rpu and the inverter chamber Rinv has a double structure. The second partition 62 is provided on the drive chamber Rpu side with respect to the first partition 60.

[0024] The case 40 further includes an oil reservoir 64 formed between the first partition 60 and the second partition 62 for storing the oil FLD scooped up by the differential ring gear 24a. The oil reservoir 64 has a pocket shape (structure) for storing the oil FLD.

[0025] Since the case 40 has an oil reservoir 64, the second partition 62 has a through hole 66 that allows the oil FLD in the drive chamber Rpu scooped up from the oil pool Roil by the differential ring gear 24a to flow into the oil reservoir 64. Arrow A in FIG. 2 shows an example of the trajectory of the oil FLD scooped up by the differential ring gear 24a. The through hole 66 is a hole that allows the oil FLD scooped up by the differential ring gear 24a to flow into the oil reservoir 64. The through hole 66 is provided vertically above the second partition 62 when the oil is mounted on the electric vehicle 10.

[0026] FIG. 3 is a diagram for explaining an example of a schematic configuration of the drive unit 50 housed in a case 70 provided in the electric vehicle 10, and is an embodiment different from that in FIG. 2. FIG. 3 is a side view of the electric vehicle 10 from the rear. In the case 40 in FIG. 2, the inverter chamber Rinv is disposed adjacent to the drive chamber Rpu in the horizontal direction, particularly in the forward direction, when mounted in the electric vehicle 10. In FIG. 3, the case 70 is mainly different from the case 40 in FIG. 2 in that the inverter chamber Rinv is disposed adjacent to the drive chamber Rpu in the horizontal direction, particularly in the vehicle width direction, when mounted in the electric vehicle 10. In the case 70, when mounted in the electric vehicle 10, the mounting position of the differential ring gear 24a is different by 90 degrees around the vertical direction from the case 40 in FIG. 2.

[0027] In the case 40 in FIG. 2, the oil FLD scooped up by the differential ring gear 24a flies mainly in the direction of the second partition wall 62 (see arrow A in FIG. 2). However, in the case 70, the oil FLD scooped up by the differential ring gear 24a flies in a direction different from the direction of the second partition wall 62. Arrow B in FIG. 3 shows an example of the trajectory of the oil FLD scooped up by the differential ring gear 24a in the case 70. Therefore, the case 70 is provided with a guide portion 72 that guides the oil FLD scooped up by the differential ring gear 24a to the through hole 66. The guide portion 72 is formed with a guide hole 74 that communicates with the through hole 66 on the outflow side of the oil FLD. The inflow side of the oil FLD in the guide hole 74 is provided in the direction in which the oil FLD scooped up by the differential ring gear 24a flies. The guide hole 74, together with the through hole 66, is a hole that allows the oil FLD scooped up by the differential ring gear 24a to flow into the oil storage portion 64. As a result, in the case 70, like the case 40, it is possible to encourage the oil FLD to flow into the oil storage portion 64.

[0028] As described above, according to this embodiment, an oil reservoir 64 is formed between the first partition 60 that separates the drive chamber Rpu and the inverter chamber Rinv, and the second partition 62 that separates the drive chamber Rpu and the inverter chamber Rinv and is provided on the drive chamber Rpu side of the first partition 60. A through hole 66 is provided vertically above the second partition 62, allowing the oil FLD scooped up by the differential ring gear 24a to flow into the oil reservoir 64. By utilizing the existing oil FLD, the rigidity of the cases 40 and 70 can be increased by the adjacent partitions 60 and 62 and the oil FLD stored in the oil reservoir 64, and a vibration-proof effect can be obtained. Therefore, both the rigidity improvement and vibration-proof effect of the cases 40 and 70 can be obtained while maintaining the space-saving structure.

[0029] Although the embodiment of the present invention has been described in detail above with reference to the drawings, the present invention can be applied to other embodiments.

[0030] For example, in the above-described embodiment, a case rib may be added between the drive chamber Rpu and the inverter chamber Rinv, or the case plate thickness may be increased, thereby further improving the rigidity.

[0031] In the above-described embodiment, a damper may be provided on the vibration generating portion of the transaxle 52 to prevent vibrations from the drive chamber Rpu from affecting the inverter chamber Rinv, thereby obtaining a further vibration-proofing effect.

[0032] It should be noted that the above is merely one embodiment, and the present invention can be embodied in various modified and improved forms based on the knowledge of those skilled in the art. [Explanation of symbols]

[0033] 10: Electric vehicle 12: Drive wheel 14: Power transmission device 24a: Differential ring gear (gear provided in the power transmission device) 32: Inverter 40: Case 52: Transaxle (drive device) 60: First partition 62: Second partition 64: Oil reservoir 66: Through hole FLD: Oil MG: Electric motor Rinv: Inverter chamber Rpu: Drive chamber

Claims

[Claim 1] An electric vehicle including an electric motor, a power transmission device that transmits power of the electric motor to drive wheels, an inverter that controls the electric motor, and a case that integrally houses the electric motor, the power transmission device, and the inverter, The case is a drive chamber that accommodates a drive unit including the electric motor and the power transmission device, and a portion of a vertical lower portion of a gear included in the power transmission device is immersed in oil when the power transmission device is mounted on the electric vehicle; an inverter chamber that houses the inverter and is disposed horizontally adjacent to the drive chamber when the inverter is mounted on the electric vehicle; a first partition wall that separates the drive chamber and the inverter chamber; a second partition wall provided on the drive chamber side of the first partition wall and separating the drive chamber from the inverter chamber; an oil reservoir formed between the first partition and the second partition, the oil reservoir configured to store the oil scooped up by a gear included in the power transmission device; a through hole provided vertically above the second partition wall in a state in which the power transmission device is mounted on the electric vehicle, through which the oil scooped up by a gear included in the power transmission device flows into the oil reservoir; An electric vehicle comprising:

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