Drive device

Abstract

The invention relates to a drive device for a vehicle. The driving device comprises a motor; the gear unit is mechanically connected with the motor; the power conversion unit is electrically connected with the motor; a housing having a first chamber and a second chamber separated from each other by a partition wall; and a cooling system that circulates a heat medium in at least one of the first chamber and the second chamber, the cooling system including a partition wall cooling path that supplies the heat medium to the partition wall, the cooling system being configured so that the heat medium flows through the partition wall cooling path compared to a state in which the vehicle speed of the vehicle is high and the output torque of the motor is low. When the vehicle speed is low and the output torque is high, the amount of the heat medium supplied to the partition cooling path is increased.

Description

Technical Field

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

[0002] The vehicle drive device disclosed in Japanese Patent Application Laid-Open No. 2023-35537 has a structure in which a housing for accommodating a power conversion unit and a housing for accommodating a motor are integrally connected. In this drive device, a partition wall separating the power conversion unit and the motor is provided with fins for air cooling.

[0003] In the drive device of Japanese Patent Application Laid-Open No. 2023-35537, optimization of cooling is not studied. As a result, the amount of heat transferred from the motor to the power conversion unit may increase during low-speed operation when the running wind cannot be expected and cooling is difficult, or during high-torque operation when the heat generated by the motor increases. As a result, the life of various electronic components of the power conversion unit may be reduced due to the increase in heat load. Summary of the invention

[0004] The vehicle drive device disclosed in the present specification includes: a motor; a gear unit, which is mechanically connected to the motor; a power conversion unit, which is electrically connected to the motor; a housing, which has a first chamber and a second chamber separated from each other by a partition wall, at least one of the motor and the gear unit is accommodated in the first chamber, and the power conversion unit is accommodated in the second chamber; and a cooling system, which circulates a heat medium in at least one of the first chamber and the second chamber, wherein the cooling system includes a partition wall cooling path for supplying the heat medium to the partition wall, and is configured to increase the supply of the heat medium to the partition wall cooling path when the vehicle speed is low and the output torque is high compared to when the vehicle speed is high and the output torque of the motor is low.

[0005] The heat medium can be set in various ways. For example, the heat medium can be oil, water, air, etc. According to the above structure, the supply amount of the heat medium to the cooling path of the next-door wall can be appropriately adjusted according to the vehicle speed and the output torque. Even under conditions where it is difficult to cool the next-door wall (for example, low vehicle speed conditions, high torque conditions), the next-door wall can be cooled. Since the amount of heat transferred from the motor to the power conversion unit can be suppressed, the increase in the heat load of the power conversion unit can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like parts, and in which:

[0007] Figure 1 It is a diagram showing a schematic configuration of the driving device 1 .

[0008] Figure 2 This is an example of the torque curve TC of the motor 40 .

[0009] Figure 3 It is a table showing the distribution of the oil supply amount.

[0010] Figure 4 It is a diagram showing a schematic configuration of the driving device 101 .

[0011] Figure 5 It is a diagram showing a schematic structure of the driving device 201.

[0012] Figure 6 It is a diagram showing a schematic structure of the driving device 301.

[0013] Figure 7 It is a diagram showing a schematic structure of the driving device 401. DETAILED DESCRIPTION

[0014] When the vehicle speed index related to the vehicle speed is lower than the first threshold, the cooling system may increase the supply amount of the heat medium to the partition-wall cooling passage in stages or continuously as the torque index related to the output torque increases.

[0015] According to the above configuration, when the vehicle speed is low, the greater the heat generated by the motor, the greater the cooling capacity of the partition wall can be increased.

[0016] Alternatively, when the vehicle speed index is lower than the first threshold and the torque index is lower than the second threshold, the cooling system adjusts the supply amount of the heat medium to the adjacent cooling path to the first supply amount. Alternatively, when the vehicle speed index is lower than the first threshold and the torque index exceeds the second threshold, the cooling system adjusts the supply amount of the heat medium to the adjacent cooling path to the second supply amount that is greater than the first supply amount.

[0017] According to the above configuration, when the vehicle speed is low, the cooling capacity of the partition wall can be increased as the output torque of the motor increases (that is, as the heat generated by the motor increases).

[0018] When the torque index related to the output torque exceeds the second threshold value, the cooling system may reduce the amount of heat medium supplied to the partition-wall cooling passage in stages or continuously as the vehicle speed index related to the vehicle speed increases.

[0019] According to the above structure, when the output torque of the motor is large, the cooling capacity of the partition wall can be reduced as the vehicle speed increases. Thus, the reduction in the cooling capacity of the partition wall can be distributed to other parts such as the motor, thereby optimizing the cooling capacity of the drive device as a whole.

[0020] Alternatively, when the torque index exceeds the second threshold and the vehicle speed index is lower than the first threshold, the cooling system adjusts the supply amount of the heat medium to the adjacent cooling path to the second supply amount. Alternatively, when the torque index exceeds the second threshold and the vehicle speed index exceeds the first threshold, the cooling system adjusts the supply amount of the heat medium to the adjacent cooling path to a third supply amount that is smaller than the second supply amount.

[0021] According to the above configuration, when the output torque is large, the cooling capacity of the partition wall can be reduced as the vehicle speed increases. Thus, the reduction in the cooling capacity of the partition wall can be distributed to other parts such as the motor.

[0022] Alternatively, at least a motor may be accommodated in the first chamber. Alternatively, the cooling system may further include a motor cooling path for supplying a heat medium to the motor. Alternatively, the cooling system may switch the ratio of the supply amount of the heat medium supplied to the adjacent cooling path to the supply amount of the heat medium supplied to the motor cooling path between at least two levels according to a combination of a vehicle speed index related to the vehicle speed and a torque index related to the output torque.

[0023] According to the above configuration, the distribution of the cooling capacity between the partition wall and the motor can be controlled by the ratio of the supply amount of the heat medium between the partition wall and the motor.

[0024] When the torque index exceeds the second threshold value, the cooling system may reduce the ratio stepwise or continuously as the vehicle speed index increases.

[0025] According to the above configuration, when the output torque of the motor is large, the cooling capacity can be allocated more to the motor than to the adjacent wall as the vehicle speed increases. Since the energy consumption of the motor can be suppressed, high efficiency can be achieved.

[0026] Alternatively, when the torque index exceeds the second threshold and the vehicle speed index is lower than the first threshold, the cooling system adjusts the ratio to the first ratio. Alternatively, when the torque index exceeds the second threshold and the vehicle speed index exceeds the first threshold, the cooling system adjusts the ratio to a second ratio that is smaller than the first ratio.

[0027] According to the above configuration, when the output torque is large, the cooling capacity can be allocated more to the motor than to the partition wall in accordance with the increase in vehicle speed.

[0028] Alternatively, the heat medium is in liquid form. Alternatively, the cooling system further includes a pump for supplying the heat medium to the adjacent cooling path and the motor cooling path. Alternatively, the cooling system further includes a flow rate adjustment unit that can adjust the ratio of the supply amount of the heat medium supplied to the adjacent cooling path to the supply amount of the heat medium supplied to the motor cooling path.

[0029] According to the above configuration, the cooling capacity can be distributed between the motor and the partition wall using the pump and the flow rate adjustment unit.

[0030] Alternatively, the heat medium may be oil. Alternatively, the first chamber may further include a gear compartment for storing the gear unit. Alternatively, the oil may be stored in the first chamber.

[0031] Alternatively, the housing may further include a storage portion for storing oil at the lower portion of the gear compartment. Alternatively, a portion of the gear unit may be immersed in the oil stored in the storage portion. Alternatively, the cooling system may further include a pump for delivering the oil stored in the storage portion to the adjacent cooling path. Alternatively, the cooling system may switch the delivery amount of the pump between at least two levels according to a combination of a vehicle speed index related to the vehicle speed and a torque index related to the output torque.

[0032] According to the above configuration, the distribution of the oil supply capacity between the partition wall and the gear unit can be controlled by the delivery amount of the pump.

[0033] The cooling system may reduce the amount of oil sent to the adjacent cooling passage in stages or continuously as the vehicle speed index increases.

[0034] According to the above structure, the amount of oil stored in the storage portion can be increased as the vehicle speed increases. Therefore, the lubricating performance of the oil can be more distributed to the gear unit as the vehicle speed increases, and seizure of the gear unit can be suppressed.

[0035] Alternatively, the first chamber further includes a motor compartment for accommodating the motor. Alternatively, the cooling system further includes a motor cooling path for supplying oil to the motor. Alternatively, the pump delivers the oil stored in the storage portion to the adjacent cooling path and the motor cooling path. Alternatively, the cooling system switches the ratio of the amount of oil supplied to the adjacent cooling path relative to the amount of oil supplied to the motor cooling path between at least two levels according to a combination of a vehicle speed index and a torque index.

[0036] According to the above configuration, it is possible to control the distribution of the oil supply capacity among the partition wall, the gear unit, and the motor.

[0037] When the torque index exceeds the second threshold value, the cooling system may reduce the ratio stepwise or continuously as the vehicle speed index increases.

[0038] According to the above configuration, when the output torque of the motor is large, the cooling capacity can be allocated more to the motor than to the adjacent wall as the vehicle speed increases. Since the energy consumption of the motor can be suppressed, high efficiency can be achieved.

[0039] [Example]

[0040] (Structure of driving device 1)

[0041] Figure 1 The schematic structure of the drive device 1 of this embodiment is shown. The drive device 1 is an integrated device in which a motor, a gear unit, and a power conversion unit for controlling the motor are accommodated in the same casing. Figure 1 Indicates the state where the drive device 1 is mounted on a vehicle (electric vehicle). The direction FR indicates the front in the front-rear direction of the vehicle. In addition, the direction RH indicates the right in the left-right direction (or width direction) of the vehicle. And the direction UP indicates the upper direction in the up-down direction of the vehicle. Figure 1 In FIG. 5 , the plurality of shafts (the motor shaft 43 , the auxiliary shaft 52 , and the drive shaft 57 ) are developed and represented in the same plane. In addition, the cooling path is represented by a solid line.

[0042] The drive device 1 is controlled by a control device 2. The control device 2 includes, for example, a CPU, a RAM, a ROM, an input / output interface, etc. The control device 2 is connected to the power conversion unit 21, the oil pump 64, the variable orifice 66, etc. via signal lines (not shown).

[0043] The driving device 1 includes a housing 10 . The housing 10 includes a first chamber 11 and a second chamber 12 which are partitioned from each other by a partition wall 13 .

[0044] The first chamber 11 includes a motor compartment 31 and a gear compartment 32. The two compartments are separated from each other by a partition wall 35. A motor 40 is accommodated in the motor compartment 31. The motor 40 includes a stator 41, a rotor 42, and a motor shaft 43. The stator 41 has a cylindrical shape. The rotor 42 is rotatably arranged inside the stator 41. The motor shaft 43 is coaxially arranged with the rotation center of the rotor 42. The motor shaft 43 is hollow.

[0045] The gear compartment 32 accommodates a gear unit 50. The gear unit 50 includes a shaft gear 51, a counter shaft 52, a first counter gear 53, a second counter gear 54, a ring gear 55, and a differential gear 56. The shaft gear 51 is attached to the motor shaft 43. Thus, the gear unit 50 and the motor 40 are mechanically connected.

[0046] A first counter gear 53 and a second counter gear 54 are mounted on the counter shaft 52. The first counter gear 53 meshes with the shaft gear 51. The second counter gear 54 meshes with the ring gear 55. The ring gear 55 is mounted on the differential gear 56. The differential gear 56 drives the drive shaft 57. When the rotation of the motor 40 is transmitted to the drive shaft 57, a pair of wheels (not shown) connected to the drive shaft 57 rotate. As a result, the vehicle travels.

[0047] The gear compartment 32 has a reservoir 33 at the bottom. The reservoir 33 stores oil 34. The oil 34 functions as a heat medium for cooling the motor 40, the partition wall 13, and the gear unit 50, and also functions as a lubricant for the gear unit 50. That is, the oil 34 has a cooling function and a lubricating function. A portion of the gear unit 50 is immersed in the oil 34 stored in the reservoir 33. Figure 1 In the example of FIG. 5 , the lower portion of the differential gear 56 is immersed in the oil 34. The stored oil 34 is lifted up by the differential gear 56, thereby lubricating each gear of the gear unit 50.

[0048] The drive device 1 also includes a cooling system 60. The cooling system 60 circulates the oil 34 stored in the first chamber 11. The cooling system 60 includes a motor cooling path 61, a partition cooling path 62, a strainer 63, an oil pump 64, an oil cooler 65, and a variable orifice 66.

[0049] The motor cooling path 61 is a path for supplying oil to the motor 40. The motor cooling path 61 is a path from the coarse filter 63 to the motor 40 via the oil pump 64 and the oil cooler 65. The coarse filter 63 is arranged in the storage section 33. The oil pump 64 sucks the oil 34 in the storage section 33 via the coarse filter 63. And the oil pump 64 sends the sucked oil to the motor cooling path 61 and the next-door cooling path 62. The delivery amount of the oil pump 64 is controlled by the control device 2. The control content of the delivery amount of the oil pump 64 will be described later. The oil cooler 65 is a heat exchanger that cools the oil by heat exchange with the refrigerant. The oil sent from the oil cooler 65 is introduced into the upper part of the motor compartment 31.

[0050] The motor cooling path 61 is branched into an upper path 61u and an axial path 61a in the motor compartment 31. The upper path 61u is provided with a plurality of discharge holes opening in a radially downward direction. The stator 41 is cooled by the oil discharged downward from the discharge holes. The motor shaft 43 is hollow (cylindrical), and an axial path 61a is provided on the axis. The axial path 61a is provided with a plurality of discharge holes penetrating in a radial direction. The oil flowing out of the discharge holes flows down to the bottom of the motor compartment 31 through a hole (not shown) in the rotor 42.

[0051] The bulkhead cooling path 62 is a path for supplying oil to the bulkhead 13. The bulkhead cooling path 62 is a path from the branch 61b of the motor cooling path 61 to the motor compartment 31 via the variable throttle hole 66 and the wall-inside flow path 62w. The variable throttle hole 66 is a flow rate adjustment unit for controlling the flow rate of the oil branching and flowing to the bulkhead cooling path 62. In other words, the variable throttle hole 66 controls the ratio of the amount of oil supplied to the bulkhead cooling path 62 to the amount of oil supplied to the motor cooling path 61. The control content of the variable throttle hole 66 will be described later. The wall-inside flow path 62w is a flow path arranged in the bulkhead 13.

[0052] The oil supplied to the motor 40 through the motor cooling path 61 and the oil supplied to the partition wall 13 through the partition wall cooling path 62 flows downward in the motor compartment 31. The flowing oil returns to the reservoir 33 in the gear compartment 32 through a communication hole (not shown) provided in the partition wall 35.

[0053] The second chamber 12 contains a power conversion unit 21. The power conversion unit 21 is a part for controlling the power supplied to the motor 40 and the generated power. As an example of the components included in the power conversion unit 21, an inverter, a converter, etc. can be cited. The power conversion unit 21 is electrically connected to the motor 40 through a bus bar 22. In addition, the power conversion unit 21 is provided with a cooling water path 23. The cooling water path 23 is provided with a water pump 24 and a radiator 25. Cooling water circulates in the cooling water path 23.

[0054] (Oil supply control)

[0055] The cooling system 60 controls the oil pump 64 and the variable throttle 66 according to a combination of a vehicle speed index and a torque index. The vehicle speed index is an index related to the vehicle speed. In the present embodiment, the vehicle speed index is the rotation speed of the motor 40. The torque index is an index related to the output torque of the motor 40. In the present embodiment, the torque index is a torque command value of the motor 40.

[0056] use Figure 2 Provide specific instructions. Figure 2 A torque curve TC of the electric machine 40 is shown. Figure 2 The horizontal axis is the rotation speed N of the motor 40, and the vertical axis is the output torque Te. The rotation speed N has a predetermined first threshold value TV1. The output torque Te has a predetermined second threshold value TV2. In addition, the first threshold value TV1 and the second threshold value TV2 can be determined in various ways. These thresholds can be fixed values, or can be calculated each time based on a calculation formula or a table.

[0057] In the rotation speed N, the range lower than the first threshold TV1 is defined as the low speed range LS, and the range higher than the first threshold TV1 is defined as the high speed range HS. In the low speed range LS, the cooling capacity of the power conversion unit 21 is lower than that in the high speed range HS. This is because the lower the vehicle speed, the lower the air volume of the running wind passing through the radiator 25, and therefore the heat dissipation of the radiator 25. Here, the running wind refers to the flow of air flowing into the engine room when the vehicle is running. As the vehicle speed increases, the air volume of the running wind also increases. In addition, the lower the vehicle speed, the more difficult it is to reduce the ambient temperature around the drive device 1. In addition, in the high speed range HS, sintering of the gear unit 50 is more likely to occur than in the low speed range LS. This is because the higher the speed at which the gear unit 50 rotates, the more likely the oil film is to break.

[0058] In the output torque Te, the range lower than the second threshold value TV2 is defined as the low torque range LT, and the range higher than the second threshold value TV2 is defined as the high torque range HT. As an example of a condition that becomes the low torque range LT, a situation of driving downhill or on flat ground can be cited. As an example of a condition that becomes the high torque range HT, a situation of driving uphill can be cited. In the high torque range HT, the heat generated by the motor 40 is greater than that in the low torque range LT. This is because the greater the output torque Te, the greater the current flowing through the motor 40.

[0059] As described above, the region of the torque curve TC is classified into four regions: a low-speed low-torque region R1, a low-speed high-torque region R2, a high-speed low-torque region R3, and a high-speed high-torque region R4. The low-speed low-torque region R1 is defined by the low-speed range LS and the low-torque range LT. The low-speed high-torque region R2 is defined by the low-speed range LS and the high-torque range HT. The high-speed low-torque region R3 is defined by the high-speed range HS and the low-torque range LT. The high-speed high-torque region R4 is defined by the high-speed range HS and the high-torque range HT. The low-speed low-torque region R1 and the high-speed low-torque region R3 are regions where the accelerator opening is relatively small. The low-speed high-torque region R2 and the high-speed high-torque region R4 are regions where the accelerator opening is relatively large.

[0060] Figure 3 The table shows the distribution of the oil supply amount among the partition wall 13, the motor 40, and the gear unit 50. Here, "priority" means increasing the oil supply amount. The cooling system 60 changes the location of the priority oil supply in each area of ​​the low speed and low torque area R1 to the high speed and high torque area R4. Specific description is given.

[0061] In the low speed and low torque region R1, the heat generated by the motor 40 is small, and the gear unit 50 is unlikely to be short of oil. Therefore, the motor 40, the gear unit 50, and the partition wall 13 do not need to be supplied with oil in priority.

[0062] In the low-speed and high-torque region R2, the oil supply to the motor 40 and the bulkhead 13 is prioritized over the oil supply to the gear unit 50. The reason for giving priority to the cooling of the motor 40 is that the heat generated by the motor 40 increases in the high-torque range HT. In addition, the reason for giving priority to the cooling of the bulkhead 13 is that the cooling capacity of the power conversion unit 21 decreases in the low-speed range LS. When the cooling capacity of the power conversion unit 21 decreases, it is difficult to remove the heat transferred from the motor 40 via the bulkhead 13. Therefore, the heat load applied to the power conversion unit 21 due to the heat generated by the motor 40 increases. Therefore, by improving the cooling function of the bulkhead 13, the heat transfer from the motor 40 can be suppressed. That is, the reduction in the cooling capacity of the power conversion unit 21 caused by the reduction in vehicle speed can be enhanced by the cooling capacity of the bulkhead 13.

[0063] In the high speed and low torque region R3, the oil supply to the gear unit 50 is prioritized over the oil supply to the motor 40 and the partition wall 13. This is because seizure of the gear unit 50 is likely to occur in the high speed range HS. Also, in the low torque range LT, the heat generated by the motor 40 is small.

[0064] In the high speed and high torque region R4, the oil supply to the motor 40 and the gear unit 50 is prioritized over the oil supply to the partition wall 13. The reason for giving priority to the cooling of the motor 40 is that the heat generated by the motor 40 increases in the high torque range HT. The reason for giving priority to the lubrication of the gear unit 50 is that the sintering of the gear unit 50 is likely to occur in the high speed range HS. In addition, the reason why the cooling of the partition wall 13 may not be prioritized is that the running air volume increases in the high speed range HS, so the cooling capacity of the power conversion unit 21 becomes higher.

[0065] (Operation and Effect of Cooling System 60)

[0066] Description for Figure 3 The specific operation of the cooling system 60 of the oil supply control is shown in FIG. 1 . The cooling system 60 adjusts the oil supply amount to the partition wall cooling path 62 to the first supply amount (see FIG. 1 ) in the low speed and low torque region R1. Figure 3 , region A1). In addition, the cooling system 60 adjusts the oil supply amount to the bulkhead cooling path 62 to a second supply amount (refer to region A2) that is larger than the first supply amount in the low speed and high torque region R2. The control of increasing the oil supply amount can be performed by at least one of increasing the oil distribution ratio to the bulkhead cooling path 62 by using the variable throttle hole 66 and increasing the delivery amount of the oil pump 64.

[0067] In other words, in the low speed range LS, the greater the output torque Te, the greater the cooling system 60 increases the amount of oil supplied to the bulkhead cooling path 62 in stages (see regions A1 and A2). Thus, when the vehicle speed is low, the cooling capacity of the bulkhead 13 can be increased in accordance with the increase in the output torque of the motor 40 (i.e., in accordance with the increase in the heat generated by the motor 40). The heat load applied to the power conversion unit 21 due to the heat generated by the motor 40 can be suppressed.

[0068] The cooling system 60 adjusts the oil supply amount to the partition wall cooling path 62 to the second supply amount (see Figure 3 , region A2). In addition, the cooling system 60 adjusts the oil supply amount to the partition wall cooling path 62 in the high speed and high torque region R4 to a third supply amount (see region A3) which is smaller than the second supply amount.

[0069] In other words, in the high torque range HT, the greater the vehicle speed, the more the cooling system 60 reduces the oil supply to the bulkhead cooling path 62 in stages (refer to regions A2 and A3). Thus, when the output torque is large, the cooling capacity of the bulkhead 13 can be reduced in accordance with the increase in vehicle speed. Therefore, the reduction in the cooling capacity of the bulkhead 13 can be distributed to other parts such as the motor 40. The cooling capacity of the drive device 1 can be optimized as a whole.

[0070] The cooling system 60 adjusts the ratio of the oil supply amount to the partition wall cooling path 62 to the oil supply amount to the motor cooling path 61 to a first ratio (see Figure 3 , regions A2 and A4). In addition, the cooling system 60 adjusts the above ratio to a second ratio (see regions A3 and A5) smaller than the first ratio in the high speed and high torque region R4. The control to reduce the above ratio can be performed by reducing the oil distribution ratio to the next-wall cooling path 62 relative to the motor cooling path 61 using the variable throttle 66.

[0071] In other words, in the high torque range HT, the greater the vehicle speed, the greater the cooling system 60 gradually reduces the oil supply ratio to the bulkhead cooling path 62. Thus, when the output torque of the motor 40 is large, the greater the vehicle speed, the greater the cooling capacity can be allocated to the motor 40 than to the bulkhead 13. Since the energy consumption of the motor 40 can be suppressed, high efficiency can be achieved.

[0072] The cooling system 60 prioritizes the oil lubrication of the gear unit 50 in the high speed and high torque region R4 (see region A7) over the oil lubrication of the gear unit 50 in the low speed and high torque region R2 (see region A6). The control to improve the oil lubrication of the gear unit 50 can be performed by reducing the oil delivery amount from the oil pump 64 to increase the oil level of the oil in the reservoir 33.

[0073] In other words, as the vehicle speed increases, the cooling system 60 gradually reduces the amount of oil delivered from the oil pump 64. As a result, as the vehicle speed increases, the lubricating performance of the oil can be more distributed to the gear unit 50. Seizing of the gear unit 50 can be suppressed.

[0074] The above detailed description of the implementation methods is provided, but these are only examples and do not limit the claims. The technology described in the claims includes technologies obtained by various deformations and changes to the specific examples illustrated above. The technical elements described in this specification or the drawings exert technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of application. In addition, the technology illustrated in this specification or the drawings achieves multiple purposes at the same time, and achieving one of the purposes itself has technical usefulness.

[0075] (First Modification)

[0076] Figure 4 1 shows a driving device 101 of a first modified example. In addition, the driving device of the modified example and the driving device 1 ( Figure 1 ) are marked with the same reference numerals, and the description is omitted. The drive device 101 is equipped with a cooling pipe 162p instead of the wall flow path 62w of the drive device 1. The cooling pipe 162p is arranged in the motor compartment 31 in a manner facing the partition wall 13. The cooling pipe 162p is provided with a plurality of discharge holes opening toward the partition wall 13. Oil is ejected from the plurality of discharge holes toward the partition wall 13 respectively. The partition wall 13 can be cooled.

[0077] (Second Modification)

[0078] Figure 5 The driving device 201 of the second modified example is shown. The driving device 201 also includes a gear cooling path 263. The gear cooling path 263 is a path for supplying oil to the gear unit 50. The gear cooling path 263 is a path from the branch 61c of the motor cooling path 61 to the gear compartment 32 via the variable throttle hole 268. In addition, a variable throttle hole 267 is arranged in the motor cooling path 61. The cooling system 60 controls the variable throttle holes 66, 267, and 268. Thus, the oil flow rate can be individually controlled in each path of the next-wall cooling path 62, the axial path 61a and the upper path 61u of the motor 40, and the gear cooling path 263. In addition, in the driving device 201, the gear cooling path 263 can also be omitted.

[0079] (Third Modification)

[0080] The second chamber 12 may be arranged in various positions. Figure 6As shown in the driving device 301 of the third modified example, the second chamber 12 may be arranged adjacent to the gear compartment 32. Thus, the unnecessary space of the gear compartment 32 can be used for the second chamber 12, so that the volume of the driving device 301 can be further reduced.

[0081] (Fourth Modification)

[0082] The heat medium for cooling the partition wall 13 is not limited to oil. Figure 7 As shown in the fourth modified example of the drive device 401, the partition wall 13 may be cooled by cooling water. In the drive device 401, the second chamber 12 is arranged adjacent to the upper part of the motor compartment 31. In addition, the ring gear 55 and the drive shaft 57 are located on the front side of the vehicle (i.e., the inner side of the paper), and are therefore illustrated with dotted lines.

[0083] The cooling water path 23 is branched into a power conversion unit cooling path 23p and a next-door cooling path 23w at the branch 23b. The next-door cooling path 23w is a path that returns from the branch 23b to the water pump 24 via the variable throttle hole 26 and the wall flow path 62w. The variable throttle hole 26 is a flow rate adjustment unit for controlling the flow rate of the cooling water that branches and flows to the next-door cooling path 23w. In other words, the variable throttle hole 26 controls the ratio of the supply amount of cooling water supplied to the next-door cooling path 23w to the supply amount of cooling water supplied to the power conversion unit cooling path 23p.

[0084] In the drive device 401 of the fourth modified example, the supply amount of the heat medium can also be controlled in the same manner as the drive device 1 of the present embodiment. That is, the supply amount of the cooling water to the bulkhead cooling path 23w can be appropriately adjusted according to the vehicle speed and the output torque. Therefore, even under conditions where it is difficult to cool the bulkhead 13 (e.g., low vehicle speed conditions, high torque conditions), the bulkhead 13 can be appropriately cooled.

[0085] (Other Modifications)

[0086] The vehicle equipped with the drive device of this specification is not limited to electric vehicles. The drive device of this specification can be installed in a hybrid vehicle or a plug-in hybrid vehicle, for example. In this case, the drive device of this specification can accommodate multiple motors in the housing, and can also accommodate a planetary gear mechanism. In addition, the drive device of this specification can also be applied to vehicles such as fuel cell vehicles that use electric motors for at least part of their driving.

[0087] The first threshold value TV1 for dividing the vehicle speed range and the second threshold value TV2 for dividing the torque range are not limited to one, but may be multiple. In addition, the adjustment of the oil supply amount based on the cooling system 60 is not limited to the method of changing in stages. For example, the oil supply amount may be changed continuously according to the change of the vehicle speed or the change of the output torque.

[0088] The vehicle speed index may be various, for example, the actual vehicle speed may be used. The torque index may be various, for example, the current value of the motor 40 may be used, or the torque measurement value by a torque sensor may be used.

[0089] The traveling wind flowing inside the vehicle may pass not only through the radiator 25 but also through the surface of the housing 10 of the drive device. In addition, ribs functioning as heat dissipation fins may be provided on the surface of the housing 10. Thus, the heat load applied from the motor 40 and the gear unit 50 side to the power conversion unit 21 side can be alleviated.

Claims

1. A driving device for a vehicle, characterized in that: include: Motor; a gear unit, the gear unit being mechanically connected to the motor; A power conversion unit, the power conversion unit is electrically connected to the motor; a housing having a first chamber and a second chamber separated from each other by a partition wall, at least one of the motor and the gear unit being accommodated in the first chamber, and the power conversion unit being accommodated in the second chamber; as well as A cooling system that circulates a heat medium in at least one of the first chamber and the second chamber, wherein: The cooling system includes a bulkhead cooling path for supplying the heat medium to the bulkhead, and is configured to increase the amount of the heat medium supplied to the bulkhead cooling path when the vehicle speed is low and the output torque is high, compared to when the vehicle speed is high and the output torque of the motor is low.

2. The driving device according to claim 1, characterized in that: The cooling system is configured to increase the supply amount of the heat medium to the partition-wall cooling passage in stages or continuously as a torque index related to the output torque increases when the vehicle speed index related to the vehicle speed is lower than a first threshold value.

3. The driving device according to claim 2, characterized in that: The cooling system is configured to adjust the supply amount of the heat medium to the partition wall cooling path to a first supply amount when the vehicle speed index is lower than the first threshold and the torque index is lower than a second threshold, When the vehicle speed index is lower than the first threshold and the torque index exceeds the second threshold, the supply amount of the heat medium to the partition wall cooling passage is adjusted to a second supply amount that is larger than the first supply amount.

4. The driving device according to claim 1, characterized in that: The cooling system is configured to reduce the amount of heat medium supplied to the partition-wall cooling passage in stages or continuously as the vehicle speed index related to the vehicle speed increases when the torque index related to the output torque exceeds a second threshold value.

5. The driving device according to claim 4, characterized in that: The cooling system is configured to adjust the supply amount of the heat medium to the partition cooling path to a second supply amount when the torque index exceeds the second threshold and the vehicle speed index is lower than a first threshold, When the torque index exceeds the second threshold value and the vehicle speed index exceeds the first threshold value, the supply amount of the heat medium to the partition wall cooling passage is adjusted to a third supply amount that is smaller than the second supply amount.

6. The driving device according to claim 1, characterized in that: The first chamber at least accommodates the motor. The cooling system further includes a motor cooling path for supplying the heat medium to the motor. The cooling system is configured to switch a ratio of a supply amount of the heat medium to the partition cooling path relative to a supply amount of the heat medium to the motor cooling path between at least two levels according to a combination of a vehicle speed index related to the vehicle speed and a torque index related to the output torque.

7. The driving device according to claim 6, characterized in that: The cooling system is configured to reduce the ratio stepwise or continuously as the vehicle speed index increases when the torque index exceeds a second threshold value.

8. The driving device according to claim 7, characterized in that: The cooling system is configured to adjust the ratio to a first ratio when the torque index exceeds the second threshold and the vehicle speed index is lower than a first threshold, When the torque index exceeds the second threshold and the vehicle speed index exceeds the first threshold, the ratio is adjusted to a second ratio that is smaller than the first ratio.

9. The driving device according to claim 6, characterized in that: The heat medium is in liquid form. The cooling system also includes: a pump that supplies the heat medium to the bulkhead cooling path and the motor cooling path; and A flow rate adjustment unit is configured to adjust a ratio between a supply amount of the heat medium supplied to the partition wall cooling channel and a supply amount of the heat medium supplied to the motor cooling channel.

10. The driving device according to claim 1, characterized in that: The heat medium is oil, The first chamber further includes a gear compartment for accommodating the gear unit. The oil is stored in the first chamber.

11. The driving device according to claim 10, characterized in that: The housing further includes a storage portion for storing the oil at a lower portion of the gear compartment. A portion of the gear unit is immersed in the oil stored in the storage portion, The cooling system further includes a pump for sending the oil stored in the storage portion to the partition wall cooling path. The cooling system is configured to switch a delivery rate of the pump between at least two levels according to a combination of a vehicle speed index related to the vehicle speed and a torque index related to the output torque.

12. The driving device according to claim 11, characterized in that: The cooling system is configured to reduce the amount of the oil sent to the partition wall cooling passage in stages or continuously as the vehicle speed index increases.

13. The driving device according to claim 12, characterized in that: The first chamber further comprises a motor compartment for accommodating the motor. The cooling system further includes a motor cooling path for supplying the oil to the motor, The pump delivers the oil stored in the storage portion to the partition wall cooling path and the motor cooling path. The cooling system is configured to switch a ratio of the amount of the oil supplied to the partition wall cooling path relative to the amount of the oil supplied to the motor cooling path between at least two levels according to a combination of the vehicle speed index and the torque index.

14. The driving device according to claim 13, characterized in that: The cooling system is configured to reduce the ratio stepwise or continuously as the vehicle speed index increases when the torque index exceeds a second threshold value.

15. The driving device according to claim 14, characterized in that: The cooling system is configured to adjust the ratio to a first ratio when the vehicle speed index is lower than a first threshold and the torque index exceeds the second threshold, When the vehicle speed index exceeds the first threshold and the torque index exceeds the second threshold, the ratio is adjusted to a second ratio that is smaller than the first ratio.

16. The driving device according to claim 15, characterized in that: The cooling system further includes a flow rate adjustment unit configured to adjust a ratio between a supply amount of the heat medium supplied to the partition wall cooling path and a supply amount of the heat medium supplied to the motor cooling path.

17. The driving device according to claim 1, characterized in that: The partition wall cooling path includes a flow path disposed in the partition wall.

18. The driving device according to claim 1, characterized in that: The partition wall cooling passage includes a portion for ejecting the heat medium toward the partition wall.

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