Drive device

Abstract

A drive device mounted on a vehicle is provided with: a housing having a motor chamber, a terminal block chamber, and a gear chamber; a motor; a terminal block; a decelerator; and a hyperbolic gear. A partition wall between the motor chamber and the terminal block chamber is provided with a first through hole. A partition wall between the terminal block chamber and the gear chamber is provided with a second through hole. The motor has a rotor shaft extending from the motor chamber to the gear chamber through the first through hole, the terminal block chamber, and the second through hole. And a gap between the rotor shaft and the second through hole is sealed by an oil seal. A first lubricating oil is accommodated in the motor chamber and the terminal block chamber. Second lubricating oil is accommodated in the gear chamber.

Description

Technical Field

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

[0002] Japanese Patent Publication No. 2004-050886 discloses a drive device for driving the wheels of a vehicle. The drive device has a motor housed in a motor chamber and a gear housed in a gear chamber. The gear in the gear chamber includes a reducer and a hypoid gear. The gear chamber is arranged next to the motor chamber. The driving force of the motor is transmitted to the drive shaft via the gear, thereby rotating the wheel. In addition, the drive device has a terminal block for supplying power to the motor. The terminal block chamber that accommodates the terminal block is arranged on the opposite side of the gear chamber across the motor chamber. That is, the motor chamber is arranged between the terminal block chamber and the gear chamber. Summary of the invention

[0003] In order to shorten the overall length of the drive device, the terminal block chamber may be provided between the motor chamber and the gear chamber. This specification proposes a technique for improving the insulation of the terminal block in a drive device in which the terminal block chamber is provided between the motor chamber and the gear chamber.

[0004] The drive device disclosed in this specification is mounted on a vehicle and includes a housing, an electric motor, a terminal block, a speed reducer, and a hypoid gear.

[0005] The housing has a motor chamber, a terminal block chamber, and a gear chamber.

[0006] The motor is accommodated in the motor chamber.

[0007] The terminal block is accommodated in the terminal block chamber and is electrically connected to the motor.

[0008] The speed reducer is arranged in the gear chamber.

[0009] The hypoid gear is disposed in the gear chamber.

[0010] A first through hole is provided in a partition wall between the motor chamber and the terminal block chamber.

[0011] A second through hole is provided in the partition wall between the terminal block chamber and the gear chamber.

[0012] The electric motor includes a rotor shaft extending from the motor chamber to the gear chamber through the first through-hole, the terminal block chamber, and the second through-hole.

[0013] The rotation of the rotor shaft is transmitted to the wheels of the vehicle via the speed reducer and the hypoid gear.

[0014] A gap between the rotor shaft and the second through hole is sealed by an oil seal.

[0015] The motor chamber and the terminal block chamber contain a first lubricating oil.

[0016] The gear chamber contains second lubricating oil.

[0017] It should be noted that the reducer and the hypoid gear can be arranged in any order. For example, the rotation of the rotor shaft can be transmitted in the order of the reducer, the hypoid gear, and the wheel, and the rotation of the rotor shaft can also be transmitted in the order of the hypoid gear, the reducer, and the wheel.

[0018] In this drive device, the terminal block chamber and the gear chamber are separated by an oil seal. Therefore, the gear chamber can contain lubricating oil different from that in the motor chamber and the terminal block chamber. Therefore, the second lubricating oil suitable for lubricating the gears can be used in the gear chamber, and the first lubricating oil suitable for lubricating the motor can be used in the motor chamber. Moreover, since the first lubricating oil is also contained in the terminal block chamber, an oil film of the first lubricating oil is formed on the surface of the terminal block. As a result, the insulation of the terminal block is improved and the terminal block can be miniaturized. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described hereinafter with reference to the accompanying drawings, wherein like reference numerals represent like elements, and wherein:

[0020] Figure 1 is a cross-sectional view of the driving device of Example 1 along the left-right direction;

[0021] Figure 2 is a cross-sectional view of the left drive system 90 along the left-right direction;

[0022] Figure 3 is a cross-sectional view of the left drive system 90 along the up-down direction;

[0023] Figure 4 is an enlarged cross-sectional view of the oil seal 25;

[0024] Figure 5 is a cross-sectional view of the driving device of Example 2; and

[0025] Figure 6 It is a cross-sectional view of the driving device of Example 3. DETAILED DESCRIPTION

[0026] The following lists additional features of the drive device disclosed in this specification.

[0027] During operation of the electric motor, the first lubricating oil may circulate between the electric motor chamber and the terminal block chamber.

[0028] According to this configuration, the electric motor can be efficiently cooled by the first lubricating oil.

[0029] The first lubricating oil may have a lower viscosity than the second lubricating oil.

[0030] According to this structure, since the viscosity of the second lubricating oil is high, the oil film on the tooth surface of the gear is suppressed from breaking. Moreover, since the viscosity of the first lubricating oil is low, the rotor of the motor can be rotated with low loss. Moreover, since the viscosity of the first lubricating oil is low, the oil film of the first lubricating oil is easily formed on the surface of the terminal block, which can effectively improve the insulation of the terminal block.

[0031] The oil seal may include: a first sealing portion contacting the outer circumferential surface of the rotor shaft and the inner circumferential surface of the second through hole; and a second sealing portion contacting the outer circumferential surface of the rotor shaft and the inner circumferential surface of the second through hole at a position closer to the gear chamber than the first sealing portion.

[0032] According to this structure, leakage of lubricating oil at the oil seal can be effectively suppressed.

[0033] The housing may be provided with an oil discharge passage that opens to the inner peripheral surface of the second through hole at a position between the first seal portion and the second seal portion.

[0034] According to this structure, the leakage of the lubricating oil at the oil seal can be suppressed more effectively.

[0035] Example 1

[0036] Figure 1 The driving device 10 of the first embodiment shown is mounted on an electric vehicle. Figure 1 In the figure, arrow FR indicates the front direction of the vehicle, and arrow RH indicates the right direction of the vehicle. The drive device 10 has a housing 12. A left drive system 90 and a right drive system 91 are provided inside the housing 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.

[0037] A left motor chamber 13, a left terminal block chamber 14, a left reversing gear chamber 15, and a left hyperbolic gear chamber 16 are provided inside the housing 12. The left terminal block chamber 14 is arranged at the rear of the left motor chamber 13. The left reversing gear chamber 15 is arranged at the rear of the left terminal block chamber 14. The left hyperbolic gear chamber 16 is arranged at the rear of the left reversing gear chamber 15. The left motor chamber 13 accommodates a motor 20. The left terminal block chamber 14 accommodates a terminal block 20e. The terminal block 20e has a terminal for supplying power to the motor 20. The left reversing gear chamber 15 accommodates a gear set constituting a reversing gear. The left hyperbolic gear chamber 16 accommodates a gear set constituting a hyperbolic gear. The left drive system 90 is constituted by the motor 20, the gear set in the left reversing gear chamber 15, and the gear set in the left hyperbolic gear chamber 16.

[0038] like Figure 2 As shown, the 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 cylindrical 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 spline fitting. The rotor 20a is housed in the left motor chamber 13 in a direction in which the rotor shaft 20c extends 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 reversing gear chamber 15. The rotor shaft 20c extends from the left motor chamber 13 to the left reversing gear chamber 15 through the through hole 18, the left terminal block chamber 14 and the through hole 19. In more detail, 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 reversing gear chamber 15. The rotor 20a is supported by a bearing provided in the housing 12 so as to be rotatable. 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 arranged around the rotor 20a. The stator 20b is electrically connected to the terminal block 20e. When current is supplied to the stator 20b via the terminal block 20e, the rotor 20a rotates.

[0039] An output shaft 24 is arranged in the left counter gear chamber 15. The output shaft 24 is arranged 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 housing 12. The output shaft 24 penetrates the partition wall between the left counter gear chamber 15 and the left hyperbolic gear chamber 16 and extends from the left counter gear chamber 15 to the left hyperbolic gear chamber 16. The output shaft 24 is rotatably supported by a bearing provided in the housing 12.

[0040] The gear set provided in the left counter gear chamber 15 includes gears 22a and 22b. Gear 22a is a cylindrical gear fixed to the rotor shaft 20c. Gear 22b is a cylindrical gear fixed to the output shaft 24. Gear 22a engages with gear 22b. The counter gear 22 is formed by gear 22a and gear 22b.

[0041] When the rotor shaft 20c rotates, the gear 22a rotates. When the gear 22a rotates, the driving force is transmitted from the gear 22a to the gear 22b. Therefore, the gear 22b and the output shaft 24 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, a speed reducer is formed by the drive system in the left counter gear chamber 15.

[0042] A drive shaft 27 is disposed in the left hyperbolic 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 hyperbolic gear chamber 16 through the left side wall of the housing 12 to the outside of the housing 12. Figure 1 As shown, the 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 housing 12.

[0043] like Figure 2 As shown, the gear set provided in the left hypoid gear chamber 16 includes gears 28a and 28b. Gear 28a is a truncated cone gear fixed to the output shaft 24. Gear 28b is a truncated cone gear fixed to the drive shaft 27. Gear 28a engages with gear 28b. Gear 28a and gear 28b constitute a hypoid gear 28.

[0044] When the 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. Therefore, 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 motor 20.

[0045] like Figure 2 As shown, the drive device 10 has an oil reservoir 46. The oil reservoir 46 may be disposed inside the housing 12 or outside the housing 12. The oil reservoir 46 stores a first lubricating oil 80. The first lubricating oil 80 circulates in the left motor chamber 13 and the left terminal block chamber 14, and the details will be described later. Figure 3As shown, a second lubricating oil 82 is stored at the bottom of the left reversing gear chamber 15 and the left hyperbolic gear chamber 16. The first lubricating oil 80 is a lubricating oil of a different type from the second lubricating oil 82. The viscosity of the first lubricating oil 80 is lower than that of the second lubricating oil 82. The left reversing gear chamber 15 is connected to the left hyperbolic gear chamber 16 at a position not shown in the figure. Therefore, the second lubricating oil 82 can flow between the left reversing gear chamber 15 and the left hyperbolic gear chamber 16. The left terminal block chamber 14 and the left reversing gear chamber 15 are separated by a partition wall except for the through hole 19. Moreover, the through hole 19 is sealed by an oil seal 25. The oil seal 25 prevents the lubricating oil from leaking between the left terminal block chamber 14 and the left reversing gear chamber 15. In this way, the left terminal block chamber 14 is separated from the left reversing gear chamber 15 so that the lubricating oils are not mixed.

[0046] 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 spread into the left counter gear chamber 15 and the left hyperbolic gear chamber 16. As a result, the gears 22a, 22b and the gears 28a, 28b are lubricated by the second lubricating oil 82. A high pressure is applied to the tooth surface of each gear. In this embodiment, since the viscosity of the second lubricating oil 82 is high, it is possible to prevent the oil film on the tooth surface of the gears 22a, 22b and the gears 28a, 28b from being broken.

[0047] like Figure 2 As shown, the drive device 10 has an oil discharge flow path 35 and an oil supply flow path 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 flow path 35 is connected to the oil discharge port 34. The downstream end of the oil discharge flow path 35 is connected to the oil storage tank 46. The upstream end of the oil supply flow path 36 is connected to the oil storage tank 46. As described above, the shaft 20c-1 has a cylindrical shape. The axial flow path 38 is formed by the center hole of the shaft 20c-1. The downstream end of the oil supply flow path 36 is connected to the front end of the axial flow path 38. An oil pump 30 is provided in the oil supply flow path 36. The oil pump 30 sends the first lubricating oil 80 from the oil storage tank 46 toward the axial flow path 38. A plurality of oil ejection ports 40 extending from the axial flow path 38 to the outer peripheral surface of the shaft 20c-1 are provided in the shaft 20c-1. An oil flow path 48 connecting the left motor chamber 13 and the left terminal block chamber 14 is provided in the housing 12.

[0048] During the operation of the motor 20, the oil pump 30 operates. When the oil pump 30 operates, the first lubricating oil 80 accumulated in the oil reservoir 46 is supplied to the axial flow path 38 in the shaft 20c-1 via the oil supply flow path 36. The first lubricating oil flows toward the rear in the axial flow path 38. The motor 20 is cooled by the first lubricating oil flowing in the axial flow path 38. The first lubricating oil in the axial flow path 38 is ejected from the oil ejection port 40 into the left motor chamber 13. The motor 20 is lubricated by the first lubricating oil ejected into the left motor chamber 13. The first lubricating oil ejected into the left motor chamber 13 flows to the left terminal block chamber 14 through the oil flow path 48. The terminal block 20e is cooled by the first lubricating oil. The first lubricating oil in the left terminal block chamber 14 flows to the oil reservoir 46 through the oil discharge port 34 and the oil discharge flow path 35. 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 insulation of the terminal block 20e is improved. In particular, since the viscosity of the first lubricating oil is low, the oil film of the first lubricating oil is easily formed on the surface of the terminal block 20e. Therefore, high insulation can be achieved in the terminal block 20e. Therefore, the insulation distance between each terminal of the terminal block 20e and the housing 12 can be shortened. Thus, the miniaturization of the drive device 10 can be achieved.

[0049] As described above, in the drive device 10 of Example 1, the left terminal block chamber 14 and the left reverse gear chamber 15 are separated by the oil seal 25, and different lubricating oils are used in each separated chamber. By using the second lubricating oil with high viscosity in the left reverse gear chamber 15 and the left hyperbolic gear chamber 16, the oil film at the tooth surface of each gear can be prevented from rupture. Moreover, by using the first lubricating oil with low viscosity in the left motor chamber 13 and the left terminal block chamber 14, 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. Moreover, by using the first lubricating oil with low viscosity in the left motor chamber 13, the rotor 20a can be rotated with low loss. Moreover, by using the same first lubricating oil (i.e., lubricating oil with low viscosity) as in the left motor chamber 13 in the left terminal block chamber 14, the insulation of the terminal block 20e can be effectively improved.

[0050] Figure 4 FIG. 2 shows a cross section of the oil seal 25 and its surroundings. Figure 4As shown, the oil seal 25 has a double lip structure that seals the oil at two locations, the sealing portions 25a and 25b. The sealing portion 25a is in contact with the outer circumferential surface of the rotor shaft 20c and the inner circumferential surface of the through hole 19. The sealing portion 25b is spaced apart from the sealing portion 25a and is arranged at a position close to the left counter gear chamber 15. The sealing portion 25b is in contact with the outer circumferential surface of the rotor shaft 20c and the inner circumferential surface of the through hole 19. In addition, an oil discharge passage 50 is formed in the housing 12, and the oil discharge passage 50 opens to the inner circumferential surface of the through hole 19 in the spacer 25c between the sealing portion 25a and the sealing portion 25b. An oil accumulation portion 52 is provided at the other end of the oil discharge passage 50. A discharge port 54 connected to the outside of the housing 12 is provided at the oil accumulation portion 52. The discharge port 54 is sealed by a cap 56. There is a case where the first lubricating oil leaks from the left terminal block chamber 14 past the sealing portion 25a into the spacer 25c. In addition, there is a case where the second lubricating oil leaks from the left reversing gear chamber 15 over the sealing portion 25b into the partition portion 25c. The lubricating oil leaking into the partition portion 25c as described above is discharged from the oil discharge path 50 to the oil accumulation portion 52. The lubricating oil accumulated in the oil accumulation portion 52 is discharged from the discharge port 54 to the outside of the housing 12 during maintenance. According to this structure, it is possible to suppress the first lubricating oil from leaking from the left terminal block chamber 14 to the left reversing gear chamber 15, and the second lubricating oil from the left reversing gear chamber 15 to the left terminal block chamber 14.

[0051] The structure of the gear may be different from that of Embodiment 1. For example, the gear may be configured as in Embodiments 2 and 3 described below.

[0052] Figure 5 The drive device of Example 2 is shown. In Example 2, 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 Example 2, the output shaft 24 is coaxially arranged with the rotor shaft 20c. The counter gear 22 transmits the rotation of the counter shaft 100 to the output shaft 24. The other structures of Example 2 are the same as those of Example 1. As in Example 2, the drive device may have a plurality of counter gears.

[0053] Figure 6 The driving device of the third embodiment is shown. In the third embodiment, an intermediate shaft 130 is arranged in the gear chamber. The intermediate shaft 130 extends in 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 structures of the third embodiment are the same as those of the first embodiment. As in the third embodiment, a counter gear may be provided at the rear stage of the hypoid gear.

[0054] The above detailed description of the implementation methods is only for illustration and does not limit the claims. The technology described in the claims includes various modifications and changes to the specific examples illustrated above. The technical elements described in this specification or drawings exert technical usefulness alone or in various combinations, and are not limited to the combinations recorded in the claims at the time of application. Moreover, the technology illustrated in this specification or drawings is a technology that achieves multiple purposes at the same time, and the achievement of one of the purposes itself has technical usefulness.

Claims

1. A driving device, the driving device being mounted on a vehicle, wherein: The driving device comprises: A housing having a motor chamber, a terminal block chamber, and a gear chamber; an electric motor, the electric motor being accommodated in the motor chamber; a terminal block, the terminal block being received in the terminal block chamber and being electrically connected to the motor; A reducer, the reducer being arranged in the gear chamber; and A hyperbolic gear is arranged in the gear chamber. A first through hole is provided in the partition wall between the motor chamber and the terminal block chamber. A second through hole is provided in the partition wall between the terminal block chamber and the gear chamber. The motor includes a rotor shaft extending from the 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 the wheels of the vehicle via the speed reducer and the hypoid gear. The 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. The gear chamber contains second lubricating oil.

2. The driving device according to claim 1, wherein: During operation of the electric motor, the first lubricating oil circulates between the electric motor chamber and the terminal block chamber.

3. The driving device according to claim 1 or 2, wherein: The first lubricating oil has a lower viscosity than the second lubricating oil.

4. The driving device according to claim 1 or 2, wherein: The oil seal includes: a first sealing portion, the first sealing portion being in contact with the outer peripheral surface of the rotor shaft and the inner peripheral surface of the second through hole; and a second sealing portion, the second sealing portion being 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 sealing portion.

5. The driving device according to claim 4, wherein: The housing is provided with an oil discharge passage, and the oil discharge passage opens to the inner peripheral surface of the second through hole at a position between the first seal portion and the second seal portion.

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