Driving device

Abstract

To provide a driving device with a terminal block chamber between an electric motor chamber and a gear chamber to improve insulation properties of the terminal block.SOLUTION: A driving device mounted on a vehicle comprises: a case with an electric motor chamber, a terminal block chamber, and a gear chamber; an electric motor; a terminal block; a reduction gear arranged in the gear chamber; and a hypoid gear arranged in the gear chamber. A first through hole is arranged at a partition wall between the electric motor chamber and the terminal block chamber. A second through hole is arranged at a partition wall between the terminal block chamber and the gear chamber. A rotor shaft of the electric motor extends from the electric motor chamber through the first through hole, the terminal block chamber, and the second through hole to the gear chamber. A gap between the rotor shaft and the second through hole is sealed with oil seal. A first lubrication oil is stored in the electric motor chamber and the terminal block chamber. A second lubrication oil is stored in the gear chamber.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a drive device.

[0002] Patent Document 1 discloses a drive device that drives the wheels of a vehicle. This drive device has an electric motor housed in an electric motor chamber and a gear housed in a gear chamber. The gears in the gear chamber include a reduction gear and a hypoid gear. The gear chamber is arranged next to the electric motor chamber. The driving force of the electric motor is transmitted to a drive shaft via the gear, thereby rotating the wheels. This drive device also has a terminal block that supplies power to the electric motor. The terminal block chamber that houses the terminal block is provided on the opposite side of the gear chamber with the electric motor chamber in between. In other words, the electric motor chamber is arranged between the terminal block chamber and the gear chamber. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-050886 A Summary of the Invention [Problem to be solved by the invention]

[0004] In order to shorten the overall length of the drive device, a terminal block chamber can be provided between the motor chamber and the gear chamber. This specification proposes a technology for improving the insulation of the terminal block in a drive device in which a terminal block chamber is provided between the motor chamber and the gear chamber. [Means for solving the problem]

[0005] The drive device disclosed in this specification is mounted on a vehicle. The drive device has a case, an electric motor, a terminal block, a reducer, and a hypoid gear. The case has an electric motor chamber, a terminal block chamber, and a gear chamber. The electric motor is accommodated in the electric motor chamber. The terminal block is accommodated in the terminal block chamber and is electrically connected to the electric motor. The reducer is disposed in the gear chamber. The hypoid gear is disposed in the gear chamber. A first through hole is provided in a partition wall between the electric motor chamber and the terminal block chamber. A second through hole is provided in a partition wall between the terminal block chamber and the gear chamber. The electric motor has a rotor shaft that extends from the electric motor chamber through the first through hole, the terminal block chamber, and the second through hole to the gear chamber. The drive device is configured so that rotation of the rotor shaft is transmitted to the wheels of the vehicle via the reducer and the hypoid gear. A gap between the rotor shaft and the second through hole is sealed by an oil seal. A first lubricating oil is contained in the motor chamber and the terminal block chamber, and a second lubricating oil is contained in the gear chamber.

[0006] The reducer and the hypoid gear may be arranged in any order. For example, the rotation of the rotor shaft may be transmitted to the reducer, the hypoid gear, and the wheels in that order, or the rotation of the rotor shaft may be transmitted to the hypoid gear, the reducer, and the wheels in that order.

[0007] In this drive device, the terminal block chamber and the gear chamber are separated by an oil seal. Therefore, a lubricant different from that in the motor chamber and the terminal block chamber can be stored in the gear chamber. Therefore, a second lubricant suitable for lubricating the gears can be used in the gear chamber, and a first lubricant suitable for lubricating the motor can be used in the motor chamber. In addition, since the first lubricant is also stored in the terminal block chamber, an oil film of the first lubricant is formed on the surface of the terminal block. This improves the insulation of the terminal block and enables the terminal block to be made smaller. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view of the drive device according to the first embodiment taken along the left-right direction. [Diagram 2] FIG. 4 is a cross-sectional view of the left drive system 90 taken along the left-right direction. [Diagram 3] FIG. 4 is a cross-sectional view of the left drive system 90 taken along the vertical direction. [Figure 4] FIG. [Diagram 5] FIG. 11 is a cross-sectional view of a drive device according to a second embodiment. [Figure 6] FIG. 11 is a cross-sectional view of a drive device according to a third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The following are additional features of the drive device disclosed in this specification:

[0010] A first lubricating oil may be circulated between the motor chamber and the terminal block chamber during operation of the motor.

[0011] According to this configuration, the electric motor can be effectively cooled by the first lubricating oil.

[0012] The viscosity of the first lubricant may be lower than the viscosity of the second lubricant.

[0013] According to this configuration, the high viscosity of the second lubricating oil suppresses oil film breakage on the gear tooth surface. Also, the low viscosity of the first lubricating oil allows the rotor of the electric motor to rotate with low loss. Also, the low viscosity of the first lubricating oil makes it easier for an oil film of the first lubricating oil to be formed on the surface of the terminal block, effectively improving the insulation of the terminal block.

[0014] The oil seal may have a first seal portion in contact with the outer peripheral surface of the rotor shaft and the inner peripheral surface of the second through hole, and a second seal portion in contact with the outer peripheral surface of the rotor shaft and the inner peripheral surface of the second through hole at a position closer to the gear chamber than the first seal portion.

[0015] With this configuration, leakage of lubricating oil from the oil seal can be effectively suppressed.

[0016] The case may be provided with an oil discharge passage that opens onto an inner circumferential surface of the second through hole at a position between the first seal portion and the second seal portion.

[0017] With this configuration, leakage of lubricating oil from the oil seal can be more effectively suppressed. EXAMPLES

[0018] A drive unit 10 of the first embodiment shown in FIG. 1 is mounted on an electric vehicle. In FIG. 1, an arrow FR indicates the front direction of the vehicle, and an arrow RH indicates the right direction of the vehicle. The drive unit 10 has a case 12. A left drive system 90 and a right drive system 91 are provided inside the case 12. The left drive system 90 drives a left rear wheel 92 of the electric vehicle. The right drive system 91 drives a right rear wheel 93 of the electric vehicle. The left drive system 90 and the right drive system 91 are symmetrical, so the left drive system 90 will be described below.

[0019] Inside the case 12, there are a left motor chamber 13, a left terminal block chamber 14, a left counter gear chamber 15, and a left hypoid gear chamber 16. The left terminal block chamber 14 is disposed rearward of the left motor chamber 13. The left counter gear chamber 15 is disposed rearward of the left terminal block chamber 14. The left hypoid gear chamber 16 is disposed rearward of the left counter gear chamber 15. The left motor chamber 13 houses an electric motor 20. The left terminal block chamber 14 houses a terminal block 20e. The terminal block 20e is provided with a terminal for supplying power to the electric motor 20. The left counter gear chamber 15 houses a gear set constituting a counter gear. The left hypoid gear chamber 16 houses a gear set constituting a hypoid gear. A left drive system 90 is constituted by the electric motor 20, the gear set in the left counter gear chamber 15, and the gear set in the left hypoid gear chamber 16, etc.

[0020] As shown in FIG. 2, the electric motor 20 has a rotor 20a and a stator 20b. The rotor 20a has a rotor shaft 20c. The rotor shaft 20c has a shaft 20c-1 and a shaft 20c-2. The shaft 20c-1 has a cylindrical shape. The shaft 20c-2 has a columnar shape. One end of the shaft 20c-2 is inserted into the shaft 20c-1. The shaft 20c-2 is fixed to the shaft 20c-1 by a spline engagement. The rotor 20a is accommodated in the left motor chamber 13 with the rotor shaft 20c extending along the front-rear direction of the electric vehicle. A through hole 18 is provided in the partition wall between the left motor chamber 13 and the left terminal block chamber 14. A through hole 19 is provided in the partition wall between the left terminal block chamber 14 and the left counter gear chamber 15. The rotor shaft 20c extends from the left motor chamber 13 to the left counter gear chamber 15 through the through hole 18, the left terminal block chamber 14, and the through hole 19. More specifically, the shaft 20c-1 extends from the left motor chamber 13 to the left terminal block chamber 14, and the shaft 20c-2 extends from the left terminal block chamber 14 to the left counter gear chamber 15. The rotor 20a is rotatably supported by a bearing provided in the case 12. The gap between the outer peripheral surface of the shaft 20c-2 and the inner peripheral surface of the through hole 19 is sealed by an oil seal 25. The stator 20b is disposed around the rotor 20a. The stator 20b is electrically connected to the terminal block 20e. When a current is supplied to the stator 20b via the terminal block 20e, the rotor 20a rotates.

[0021] An output shaft 24 is disposed in the left counter gear chamber 15. The output shaft 24 is disposed parallel to the rotor shaft 20c. More specifically, the central axis of the output shaft 24 is parallel to the central axis of the rotor shaft 20c. The output shaft 24 is rotatably supported by a bearing provided in the case 12. The output shaft 24 penetrates a partition wall between the left counter gear chamber 15 and the left hypoid gear chamber 16 and extends from the left counter gear chamber 15 to the left hypoid gear chamber 16. The output shaft 24 is rotatably supported by a bearing provided in the case 12.

[0022] The gear set provided in the left counter gear chamber 15 has gears 22a and 22b. The gear 22a is a cylindrical gear and is fixed to the rotor shaft 20c. The gear 22b is a cylindrical gear and is fixed to the output shaft 24. The gear 22a is engaged with the gear 22b. The gears 22a and 22b form a counter gear 22.

[0023] When the rotor shaft 20c rotates, the gear 22a rotates. When the gear 22a rotates, a driving force is transmitted from the gear 22a to the gear 22b. This causes the gear 22b and the output shaft 24 to rotate. The gear ratio of the counter gear 22 is set so that the rotation speed of the output shaft 24 is slower than the rotation speed of the rotor shaft 20c. In this way, the drive system in the left counter gear chamber 15 constitutes a reducer.

[0024] A drive shaft 27 is disposed in the left hypoid gear chamber 16. The drive shaft 27 extends in the left-right direction of the electric vehicle. The drive shaft 27 extends from the left hypoid gear chamber 16 through the left wall of the case 12 to the outside of the case 12. As shown in FIG. 1, a left rear wheel 92 is connected to the left end of the drive shaft 27. The drive shaft 27 is rotatably supported by a bearing provided in the case 12.

[0025] As shown in Fig. 2, the gear set provided in the left hypoid gear chamber 16 has gears 28a and 28b. Gear 28a is a truncated cone gear and is fixed to the output shaft 24. Gear 28b is a truncated cone gear and is fixed to the drive shaft 27. Gear 28a is engaged with gear 28b. Gears 28a and 28b form a hypoid gear 28.

[0026] When the electric motor 20 is driven, the rotor shaft 20c rotates. As described above, when the rotor shaft 20c rotates, the output shaft 24 rotates. When the output shaft 24 rotates, the gear 28a rotates, and the driving force is transmitted from the gear 28a to the gear 28b. As a result, the gear 28b and the drive shaft 27 rotate. When the drive shaft 27 rotates, the left rear wheel 92 rotates. In this way, the left drive system 90 rotates the left rear wheel 92 by the driving force of the electric motor 20.

[0027] As shown in FIG. 2, the drive unit 10 has an oil storage tank 46. The oil storage tank 46 may be provided inside the case 12. It may be provided outside the case 12. A first lubricating oil 80 is stored in the oil storage tank 46. As will be described later in detail, the first lubricating oil 80 circulates through the left motor chamber 13 and the left terminal block chamber 14. As shown in FIG. 3, a second lubricating oil 82 is stored in the bottom of the left counter gear chamber 15 and the left hypoid gear chamber 16. The first lubricating oil 80 is a different type of lubricating oil from the second lubricating oil 82. The viscosity of the first lubricating oil 80 is lower than the viscosity of the second lubricating oil 82. The left counter gear chamber 15 and the left hypoid gear chamber 16 are connected at a position not shown. Therefore, the second lubricating oil 82 can flow between the left counter gear chamber 15 and the left hypoid gear chamber 16. The left terminal block chamber 14 and the left counter gear chamber 15 are separated by a partition wall, except for the through hole 19. Furthermore, the through hole 19 is sealed by an oil seal 25. The oil seal 25 prevents lubricating oil from leaking between the left terminal block chamber 14 and the left counter gear chamber 15. In this way, the left terminal block chamber 14 and the left counter gear chamber 15 are separated so that the lubricating oils do not mix.

[0028] The lower part of the gear 28b is immersed in the second lubricating oil 82. Therefore, when the gear 28b rotates, the second lubricating oil 82 is dispersed into the left counter gear chamber 15 and the left hypoid gear chamber 16. As a result, the gears 22a, 22b and the gears 28a, 28b are lubricated by the second lubricating oil 82. High pressure is applied to the tooth surfaces of each gear. In this embodiment, since the viscosity of the second lubricating oil 82 is high, oil film breakdown on the tooth surfaces of the gears 22a, 22b and the gears 28a, 28b is prevented.

[0029] As shown in FIG. 2, the drive unit 10 has an oil discharge passage 35 and an oil supply passage 36. In addition, an oil discharge port 34 is formed at the bottom of the left terminal block chamber 14. The upstream end of the oil discharge passage 35 is connected to the oil discharge port 34. The downstream end of the oil discharge passage 35 is connected to the oil storage tank 46. The upstream end of the oil supply passage 36 is connected to the oil storage tank 46. As described above, the shaft 20c-1 has a cylindrical shape. The shaft passage 38 is formed by the central hole of the shaft 20c-1. The downstream end of the oil supply passage 36 is connected to the front end of the shaft passage 38. The oil supply passage 36 is provided with an oil pump 30. The oil pump 30 sends out the first lubricating oil 80 from the oil storage tank 46 toward the shaft passage 38. The shaft 20c-1 is provided with a plurality of oil discharge ports 40 extending from the shaft passage 38 to the outer circumferential surface of the shaft 20c-1. The case 12 is provided with an oil flow passage 48 that connects the left motor chamber 13 and the left terminal block chamber 14 .

[0030] During the operation of the electric motor 20, the oil pump 30 operates. When the oil pump 30 operates, the first lubricating oil 80 stored in the oil reservoir 46 is supplied to the shaft flow passage 38 in the shaft 20c-1 through the oil supply flow passage 36. The first lubricating oil flows backward through the shaft flow passage 38. The electric motor 20 is cooled by the first lubricating oil flowing through the shaft flow passage 38. The first lubricating oil in the shaft flow passage 38 is discharged from the oil discharge port 40 into the left electric motor chamber 13. The electric motor 20 is lubricated by the first lubricating oil discharged into the left electric motor chamber 13. The first lubricating oil discharged into the left electric motor chamber 13 flows through the oil flow passage 48 to the left terminal block chamber 14. The terminal block 20e is cooled by the first lubricating oil. The first lubricating oil in the left terminal block chamber 14 flows through the oil discharge port 34 and the oil discharge flow passage 35 to the oil reservoir 46. As described above, when the oil pump 30 operates, the first lubricating oil circulates between the left motor chamber 13 and the left terminal block chamber 14. When the first lubricating oil circulates, the first lubricating oil is applied to the surface of the terminal block 20e. Therefore, an oil film of the first lubricating oil is formed on the surface of the terminal block 20e. Since the surface of the terminal block 20e is covered with the oil film of the first lubricating oil, the insulating property of the terminal block 20e is improved. In particular, since the viscosity of the first lubricating oil is low, an oil film of the first lubricating oil is easily formed on the surface of the terminal block 20e. Therefore, high insulating property can be realized in the terminal block 20e. Therefore, it is possible to shorten the insulating distance between each terminal of the terminal block 20e and the case 12. This realizes a reduction in size of the drive device 10.

[0031] As described above, in the drive device 10 of the first embodiment, the left terminal block chamber 14 and the left counter gear chamber 15 are separated by the oil seal 25, and different lubricating oils are used in each separated chamber. The second lubricating oil having a high viscosity is used in the left counter gear chamber 15 and the left hypoid gear chamber 16, so that the oil film on the tooth surface of each gear is prevented from being broken. In addition, the first lubricating oil having a low viscosity is used in the left motor chamber 13 and the left terminal block chamber 14, so that the first lubricating oil can be efficiently circulated by the oil pump 30, and the motor 20 and the terminal block 20e can be efficiently cooled. In addition, the first lubricating oil having a low viscosity is used in the left motor chamber 13, so that the rotor 20a can be rotated with low loss. In addition, the first lubricating oil (i.e., the lubricating oil having a low viscosity) common to the left motor chamber 13 is used in the left terminal block chamber 14, so that the insulation of the terminal block 20e can be effectively improved.

[0032] FIG. 4 shows a cross section of the oil seal 25 and its surroundings. As shown in FIG. 4, the oil seal 25 has a double lip structure that seals the oil at two points, the seal parts 25a and 25b. The seal part 25a contacts the outer peripheral surface of the rotor shaft 20c and the inner peripheral surface of the through hole 19. The seal part 25b is disposed at a position close to the left counter gear chamber 15 with a gap therebetween from the seal part 25a. The seal part 25b contacts the outer peripheral surface of the rotor shaft 20c and the inner peripheral surface of the through hole 19. In addition, the case 12 is formed with an oil discharge passage 50 that opens to the inner peripheral surface of the through hole 19 in the gap part 25c between the seal parts 25a and 25b. An oil reservoir 52 is provided at the other end of the oil discharge passage 50. The oil reservoir 52 is provided with a discharge port 54 that is connected to the outside of the case 12. The discharge port 54 is closed by a cap 56. The first lubricating oil may leak from the left terminal block chamber 14 past the seal portion 25a into the gap portion 25c. The second lubricating oil may leak from the left counter gear chamber 15 past the seal portion 25b into the gap portion 25c. The lubricating oil leaked into the gap portion 25c in this manner is discharged from the oil drain path 50 into the oil reservoir 52. The lubricating oil accumulated in the oil reservoir 52 is discharged from the drain port 54 to the outside of the case 12 during maintenance. This configuration makes it possible to suppress leakage of the first lubricating oil from the left terminal block chamber 14 to the left counter gear chamber 15 and leakage of the second lubricating oil from the left counter gear chamber 15 to the left terminal block chamber 14.

[0033] The gear configuration may be different from that of Example 1. For example, the gear may be configured as in Examples 2 and 3 described below.

[0034] FIG. 5 shows a drive device of the second embodiment. In the second embodiment, a counter shaft 100 and a counter gear 110 are housed in the left counter gear chamber 15. The counter gear 110 transmits the rotation of the rotor shaft 20c to the counter shaft 100. In the second embodiment, the output shaft 24 is arranged coaxially with the rotor shaft 20c. The counter gear 22 transmits the rotation of the counter shaft 100 to the output shaft 24. Other configurations of the second embodiment are the same as those of the first embodiment. As in the second embodiment, the drive device may have multiple counter gears.

[0035] FIG. 6 shows a drive unit of the third embodiment. In the third embodiment, an intermediate shaft 130 is disposed in the gear chamber. The intermediate shaft 130 extends along the left-right direction of the vehicle. The hypoid gear 28 is provided between the rotor shaft 20c and the intermediate shaft 130. The hypoid gear 28 transmits the rotation of the rotor shaft 20c to the intermediate shaft 130. The counter gear 22 is provided between the intermediate shaft 130 and the drive shaft 27. The counter gear 22 transmits the rotation of the intermediate shaft 130 to the drive shaft 27. The other configurations of the third embodiment are the same as those of the first embodiment. As in the third embodiment, a counter gear may be provided behind the hypoid gear.

[0036] Although the embodiments have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes to the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or drawings achieves multiple objectives simultaneously, and achieving one of the objectives itself has technical utility. [Explanation of symbols]

[0037] 10: Drive unit 12: Case 13:Left motor room 14:Left terminal block room 15: Left counter gear room 16: Left hypoid gear chamber 18:Through hole 19:Through hole 20: Electric motor 20c: rotor shaft 20e:Terminal block 22: Counter gear 27: Drive shaft 28: Hypoid gear 80:1st lubricant 82:Second lubricant

Claims

1. A drive device mounted on a vehicle, a case having a motor chamber, a terminal block chamber, and a gear chamber; an electric motor accommodated in the electric motor chamber; a terminal block housed in the terminal block chamber and electrically connected to the electric motor; A reducer disposed in the gear chamber; and a hypoid gear disposed in the gear chamber; having a first through hole is provided in a partition wall between the motor chamber and the terminal block chamber, A second through hole is provided in a partition wall between the terminal block chamber and the gear chamber, the electric motor has a rotor shaft extending from the electric motor chamber through the first through hole, the terminal block chamber, and the second through hole to the gear chamber, The rotation of the rotor shaft is transmitted to wheels of the vehicle via the reduction gear and the hypoid gear, a gap between the rotor shaft and the second through hole is sealed by an oil seal, A first lubricant is contained in the motor chamber and the terminal block chamber, A second lubricant is contained in the gear chamber. Drive unit.

2. The drive device according to claim 1 , wherein the first lubricating oil circulates between the motor chamber and the terminal block chamber during operation of the motor.

3. The drive unit according to claim 1 or 2, wherein the first lubricant oil has a lower viscosity than the second lubricant oil.

4. 3. The drive device described in claim 1 or 2, wherein the oil seal has a first seal portion that contacts the outer peripheral surface of the rotor shaft and the inner peripheral surface of the second through hole, and a second seal portion that contacts the outer peripheral surface of the rotor shaft and the inner peripheral surface of the second through hole at a position closer to the gear chamber than the first seal portion.

5. The drive unit according to claim 4 , wherein the case is provided with an oil discharge passage that opens onto the inner circumferential surface of the second through hole at a position between the first seal portion and the second seal portion.

Images