motor unit

Abstract

In the motor unit, oil that has not been cooled by the oil cooler can be supplied to the motor chamber, thus enabling the motor unit to be miniaturized. The motor unit includes a housing, a motor chamber within the housing, and an oil supply device for supplying oil to the gear chamber. The oil supply device includes an oil pump, an oil cooler, a first oil flow path, and a second oil flow path. The first oil flow path is configured to supply oil supplied from the oil pump when a first valve is open, and connects the oil pump, the oil supply port of the gear chamber, and a first end of the internal flow path of the oil cooler. The second oil flow path is configured to supply oil supplied from the oil pump when a second valve is open, and connects the oil pump, the oil supply port of the motor chamber, and a second end of the internal flow path.

Description

Technical Field

[0001] The technology disclosed in this specification relates to motor units. Background Technology

[0002] In the motor unit disclosed in Patent Document 1, a motor chamber and a gear chamber are provided in the housing. A motor is housed in the motor chamber, and a gear is housed in the gear chamber. Furthermore, this motor unit includes an oil cooler for cooling oil. Oil cooled by the oil cooler is supplied to the housing. This cools the motor unit.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2024-131256 Summary of the Invention

[0004] If the oil temperature is low, the oil viscosity will increase. If oil cooled by the cooler is supplied to the motor chamber when the motor temperature is low, it will lead to a decrease in motor efficiency. This specification proposes a technique for supplying oil that has not been cooled by the oil cooler to the motor chamber in a motor unit, thereby enabling the miniaturization of the motor unit.

[0005] The motor unit disclosed in this specification includes: a housing having a motor chamber and a gear chamber; a motor disposed within the motor chamber; a gear disposed within the gear chamber and engaging with the rotating shaft of the motor; and an oil supply device for supplying oil to the motor chamber and the gear chamber. The oil supply device includes an oil pump, an oil cooler, a first oil flow path, and a second oil flow path. The first oil flow path is provided with a first valve configured to allow oil supplied from the oil pump to flow when the first valve is open, and connects the oil pump, the oil supply port of the gear chamber, and a first end of the internal flow path of the oil cooler. The second oil flow path is provided with a second valve configured to allow oil supplied from the oil pump to flow when the second valve is open, and connects the oil pump, the oil supply port of the motor chamber, and a second end of the internal flow path.

[0006] This motor unit is capable of performing a first action of opening the first valve and a second action of opening the second valve. In the first action, oil is supplied to the gear chamber and the oil cooler via the first oil flow path. Oil flowing from the first end to the second end through the oil cooler (i.e., the internal flow path) is supplied to the motor chamber via the second oil flow path. Thus, in the first action, oil is supplied to both the motor chamber and the gear chamber. In this case, the low-temperature oil that has passed through the oil cooler is supplied to the motor chamber. In the second action, oil is supplied to both the motor chamber and the oil cooler via the second oil flow path. Oil flowing from the second end to the first end through the oil cooler (i.e., the internal flow path) is supplied to the gear chamber via the first oil flow path. Thus, in the second action, oil is also supplied to both the motor chamber and the gear chamber. In this case, the relatively high-temperature oil that has not passed through the oil cooler is supplied to the motor chamber. As explained above, according to this structure, it is possible to switch between the first action of supplying oil that has passed through the oil cooler to the motor chamber and the second action of supplying oil that has not passed through the oil cooler to the motor chamber. Furthermore, in this structure, the oil flows bidirectionally within the oil cooler during both the first and second operations, thus eliminating the need for a bypass path to the oil cooler. This allows for miniaturization of the motor unit. Attached Figure Description

[0007] Figure 1 This is a picture of the vehicle viewed from the side.

[0008] Figure 2 This is a 3D view of motor unit 16.

[0009] Figure 3 This is a cross-sectional view showing the internal structure of the housing 20.

[0010] Figure 4 This is a diagram showing the flow path of the oil supply device 70.

[0011] Figure 5 This is a diagram showing the bypass flow path 100 of the oil supply device 70 in the comparative example.

[0012] Explanation of reference numerals in the attached figures

[0013] 16...Motor unit; 21...Gear chamber oil supply port; 23...Motor chamber oil supply port; 30...Gear mechanism; 30a...Gear chamber; 60...Motor; 60a...Motor chamber; 70...Oil supply device; 74...Oil pump; 76...Oil cooler Detailed Implementation

[0014] In one example of the motor unit disclosed in this specification, the cooling performance of the oil cooler is higher when the oil flows from the first end to the second end in the internal flow path, compared to the case where the oil flows from the second end to the first end in the internal flow path.

[0015] According to this structure, low-viscosity oil can be supplied to the gear chamber in the second operation.

[0016] In one example of the motor unit disclosed in this specification, the motor unit may also be mounted in a vehicle. Alternatively, the oil supply port of the motor housing and the oil supply port of the gear housing may be spaced apart in the vehicle width direction. Alternatively, the oil cooler may have a shape that is longer in the vehicle width direction. Alternatively, the first end and the second end may be positioned in the vehicle width direction between the oil supply port of the motor housing and the oil supply port of the gear housing, with the first end positioned closer to the oil supply port of the gear housing than the second end.

[0017] According to this structure, the flow path between the motor chamber and the second end, as well as the flow path between the gear chamber and the first end, can be shortened.

[0018] Figure 1 The vehicle 10 shown is a vehicle having at least one electric motor as a drive source. The vehicle 10 may also be, for example, an electric vehicle, a hybrid vehicle, or a fuel cell vehicle.

[0019] Vehicle 10 has a battery pack 12 mounted below the floor and two motor units 16 and 18. The battery pack 12 supplies power to motor units 16 and 18 respectively. Motor unit 16 drives the front wheels 13, and motor unit 18 drives the rear wheels 14. Furthermore, vehicle 10 is illustrated as a four-wheel drive vehicle, but it could also be a two-wheel drive vehicle equipped with only one of motor units 16 and 18. Motor units 16 and 18 have a common structure. Motor unit 16 will be described below.

[0020] like Figure 2 As shown, the motor unit 16 includes a housing 20, a motor 60, a gear mechanism 30, and a power control unit 19. The motor 60, gear mechanism 30, and power control unit 19 are housed within the housing 20. The power control unit 19 is positioned adjacent to the motor 60 and gear mechanism 30 in the longitudinal direction of the vehicle (in this example, the rear of the vehicle). The power control unit 19 converts the power supplied from the battery pack 12 from direct current (DC) to alternating current (AC) and supplies it to the motor 60. The motor 60 generates driving force based on the AC power supplied from the power control unit 19. The gear mechanism 30 amplifies the driving force generated by the motor 60 and distributes it to the left and right wheels.

[0021] like Figure 3 As shown, a motor chamber 60a for housing the motor 60 and a gear chamber 30a for housing the gear mechanism 30 are provided inside the housing 20. The motor chamber 60a and the gear chamber 30a are connected to each other.

[0022] The motor 60 includes a stator 62 and a rotor 64. The stator 62 is fixed to the housing 20. The rotor 64 is concentrically disposed inside the stator 62. The rotor 64 is supported in the housing 20 in a manner that allows it to rotate freely about its central axis. The output shaft 66 of the rotor 64 is hollow. That is, a through hole 66a extending along its central axis is provided in the output shaft 66.

[0023] The gear mechanism 30 includes a planetary gear mechanism 40 and a differential gear 50. Both the planetary gear mechanism 40 and the differential gear 50 are composed of multiple gears. The planetary gear mechanism 40 reduces the rotation of the output shaft 66 of the motor 60. The differential gear 50 distributes the driving force of the motor 60 transmitted via the planetary gear mechanism 40 to the left and right front wheels 13a and 13b. The motor 60, the planetary gear mechanism 40, and the differential gear 50 are arranged coaxially. Furthermore, the structure of the gear mechanism 30 described below is an example; other types of structures can be appropriately adopted.

[0024] The planetary gear mechanism 40 includes a sun gear 42, multiple stepped pinions 44, a ring gear 46, and a planet carrier 48. The sun gear 42 is connected to the output shaft 66 of the motor 60 and rotates integrally with the output shaft 66. Each of the multiple stepped pinions 44 has a large-diameter pinion P1 and a small-diameter pinion P2 with a smaller diameter than the large-diameter pinion P1. The large-diameter pinion P1 meshes with the sun gear 42. The small-diameter pinion P2 meshes with the ring gear 46. The ring gear 46 is fixed to the housing 20. The planet carrier 48 rotatably supports each of the multiple stepped pinions 44. Thus, in the planetary gear mechanism 40, the sun gear 42 is the input element, the ring gear 46 is the reaction force element, and the planet carrier 48 is the output element.

[0025] The differential gear 50 includes a differential housing 51. The differential housing 51 is supported on the housing 20 in a manner that allows it to rotate freely about the rotation axis of the motor 60. The differential housing 51 is connected to the planet carrier 48 of the planetary gear mechanism 40 and rotates integrally with the planet carrier 48.

[0026] The differential housing 51 contains a pinion shaft 53, a pair of differential pinions 54 and 55, and side gears 56 and 57.

[0027] The pinion shaft 53 is connected to the differential housing 51 and rotates integrally with it. The pinion shaft 53 extends within the differential housing 51 in a direction orthogonal to the rotational axis of the motor 60. A pair of differential pinions 54 and 55 are supported on the pinion shaft 53 in a manner that allows them to rotate freely about its axis. The side gear 56 is the component that outputs driving force to the front wheel 13a and meshes with the pair of differential pinions 54 and 55. The side gear 57 is the component that outputs driving force to the front wheel 13b and meshes with the pair of differential pinions 54 and 55.

[0028] The motor unit 16 also includes drive shafts 58 and 59. Drive shaft 58 is inserted into a through hole 66a of output shaft 66. Drive shaft 58 connects side gear 56 to front wheel 13a. Drive shaft 59 connects side gear 57 to front wheel 13b. Drive shafts 58 and 59 transmit driving force from differential gear 50 to the left and right front wheels 13a and 13b.

[0029] Lubricating oil accumulates at the bottom of the housing 20. The housing 20 is provided with an oil drain port 24, motor chamber oil supply ports 22 and 23, and gear chamber oil supply port 21. The oil drain port 24 is located at the bottom of the housing 20. The oil drain port 24 discharges the oil accumulated in the housing 20 to the outside of the housing 20. Oil is supplied from the outside to the motor chamber oil supply ports 22 and 23 and the gear chamber oil supply port 21. The motor chamber oil supply ports 22 and 23 are located at the upper part of the motor chamber 60a. The motor chamber oil supply port 22 discharges the externally supplied oil toward the stator 62. The motor chamber oil supply port 23 is connected to a cooling flow path 62a located inside the stator 62. The oil supplied from the outside to the motor chamber oil supply port 23 flows within the cooling flow path 62a. The oil passing through the cooling flow path 62a is discharged into the motor chamber 60a. The gear chamber oil supply port 21 is located at the upper part of the gear chamber 30a. The gear chamber oil supply port 21 discharges externally supplied oil toward the gears inside the gear chamber 30a.

[0030] Figure 4 This is a diagram showing the front compartment 11 of vehicle 10 as viewed from above. (See diagram below.) Figure 4 As shown, a housing 20 is disposed within the front compartment 11. Additionally, the motor unit 16 has an oil supply device 70. The oil supply device 70 supplies oil to the housing 20. The oil supply device 70 includes an oil pump 74 and an oil cooler 76. The oil cooler 76 has an internal flow path 76a for oil flow. The internal flow path 76a has connection ports 76a-1 and 76a-2 at both ends. The oil cooler 76 cools the oil flowing within the internal flow path 76a through heat exchange. The oil pump 74 and the oil cooler 76 are disposed on the upper part of the housing 20.

[0031] like Figure 4 As shown, the oil supply device 70 has a first oil flow path 71 and a second oil flow path 72 disposed on the upper part of the housing 20. Additionally, as... Figure 3 As shown, the oil supply device 70 has an oil discharge passage 75 connected to the lower part of the housing 20.

[0032] like Figure 3 As shown, the upstream end of the oil discharge path 75 is connected to the oil discharge port 24 located on the bottom surface of the housing 20. The downstream end of the oil discharge path 75 is connected to the suction port of the oil pump 74. The oil pump 74 draws oil stored at the bottom of the housing 20 via the oil discharge path 75.

[0033] like Figure 4 As shown, the first oil flow path 71 and the second oil flow path 72 are connected to the outlet of the oil pump 74. The oil pump 74 delivers the oil drawn from the oil discharge flow path 75 to the first oil flow path 71 and the second oil flow path 72.

[0034] The first oil flow path 71 connects the oil pump 74, the gear chamber oil supply port 21, and the connection port 76a-1 of the oil cooler 76. The first oil flow path 71 includes a pump flow path 71a, a gear chamber flow path 71b, and an oil cooler flow path 71c. The upstream end of the pump flow path 71a is connected to the discharge port of the oil pump 74. A valve 77 is installed in the pump flow path 71a. The valve 77 opens and closes the pump flow path 71a. The downstream end of the pump flow path 71a is connected to the upstream ends of the gear chamber flow path 71b and the oil cooler flow path 71c. The downstream end of the gear chamber flow path 71b is connected to the gear chamber oil supply port 21. The downstream end of the oil cooler flow path 71c is connected to the connection port 76a-1.

[0035] The second oil flow path 72 connects the oil pump 74, the motor chamber oil supply ports 22 and 23, and the connection port 76a-2 of the oil cooler 76. The second oil flow path 72 has a pump flow path 72a and a motor chamber flow path 72b. The upstream end of the pump flow path 72a is connected to the discharge port of the oil pump 74. A valve 78 is provided in the pump flow path 72a. The valve 78 opens and closes the pump flow path 72a. The downstream end of the pump flow path 72a is connected to the upstream end of the motor chamber flow path 72b and the connection port 76a-2 of the oil cooler 76. The downstream portion of the motor chamber flow path 72b is divided into two. The downstream end of one side of the motor chamber flow path 72b is connected to the motor chamber oil supply port 22. The downstream end of the other side of the motor chamber flow path 72b is connected to the motor chamber oil supply port 23. The oil supply device 70 has a control device (not shown) and controls the oil pump 74 and valves 77 and 78 through the control device.

[0036] The oil supply device 70 supplies oil to the housing 20 during the operation of the motor 60. The oil supplied to the housing 20 lubricates and cools the motor 60 and gears. Furthermore, the oil supply device 70 is capable of performing a first action of supplying oil cooled by the oil cooler 76 to the motor chamber 60a, and a second action of supplying oil not cooled by the oil cooler 76 to the motor chamber 60a. The oil supply device 70 detects the temperature of the motor 60 using a temperature sensor or similar means, and performs the first and second actions based on the detected temperature.

[0037] When the temperature of motor 60 is higher than the reference value, oil supply device 70 performs a first action. In this first action, oil supply device 70 opens valve 77 and closes valve 78, thereby activating oil pump 74. Therefore, oil pump 74 discharges oil into pump flow path 71a. The oil in pump flow path 71a flows in branches to gear chamber flow path 71b and oil cooler flow path 71c.

[0038] Oil in the gear chamber flow path 71b is discharged from the gear chamber oil supply port 21 toward the gears in the gear chamber 30a. Thus, the gears in the gear chamber 30a are lubricated.

[0039] Oil in the oil cooler flow path 71c flows into the internal flow path 76a from the connection port 76a-1. The oil flowing in the internal flow path 76a is cooled by the oil cooler 76. Oil in the internal flow path 76a flows into the motor chamber flow path 72b from the connection port 76a-2. Oil in the motor chamber flow path 72b is supplied to the motor chamber 60a from the motor chamber oil supply ports 22 and 23. Oil supplied to the motor chamber 60a from the motor chamber oil supply port 22 flows into the cooling flow path 62a of the stator 62. The stator 62 is cooled by the oil flowing into the cooling flow path 62a. The oil flowing through the cooling flow path 62a is discharged into the motor chamber 60a. In addition, oil is discharged from the motor chamber oil supply port 23 toward the stator 62. The stator 62 is also cooled by this. In addition, the motor 60 is lubricated by the oil discharged into the motor chamber 60a.

[0040] As explained above, in the first operation performed when the motor 60 is at a high temperature, oil cooled by the oil cooler 76 is supplied into the motor chamber 60a. The oil cooler 76 efficiently cools the oil as it flows from connection port 76a-1 towards connection port 76a-2 within the internal flow path 76a. Therefore, in the first operation, sufficiently cool oil is supplied into the motor chamber 60a. Thus, the motor 60 is cooled efficiently.

[0041] When the temperature of motor 60 is below a reference value, oil supply device 70 performs a second action. In this second action, oil supply device 70 closes valve 77 and opens valve 78, thereby activating oil pump 74. Therefore, oil pump 74 discharges oil into pump flow path 72a. The oil in pump flow path 72a flows in a branch path to motor chamber flow path 72b and connection port 76a-2.

[0042] Oil in the motor chamber flow path 72b is supplied to the motor chamber 60a through the motor chamber oil supply ports 22 and 23. The stator 62 is cooled by the oil flowing from the motor chamber oil supply port 22 to the cooling flow path 62a. Additionally, oil is discharged from the motor chamber oil supply port 23 toward the stator 62, thus also cooling the stator 62. Furthermore, the oil discharged into the motor chamber 60a lubricates the motor 60.

[0043] After flowing from pump flow path 72a to connection port 76a-2, the oil flows from connection port 76a-2 into internal flow path 76a. The oil flowing in internal flow path 76a is cooled by oil cooler 76. The oil in internal flow path 76a flows from connection port 76a-1 through oil cooler flow path 71c to gear chamber flow path 71b. The oil in gear chamber flow path 71b is discharged from gear chamber oil supply port 21 towards the gears in gear chamber 30a. Thus, the gears in gear chamber 30a are lubricated.

[0044] As explained above, in the second operation performed when the motor 60 is at a low temperature, oil that has not passed through the oil cooler 76 (i.e., oil not cooled by the oil cooler 76) is supplied to the motor chamber 60a. The oil supplied to the motor chamber 60a has a relatively high temperature, and therefore a low viscosity. Thus, losses due to oil viscosity are less likely to occur in the motor 60, and the motor 60 can operate efficiently. In this way, by supplying relatively hot oil to the motor chamber 60a when the motor 60 temperature is sufficiently low, the operating efficiency of the motor 60 is improved. Furthermore, although oil cooled by the oil cooler 76 is supplied to the gear chamber 30a in the second operation, the gears are less affected by oil viscosity compared to the motor 60, so even if high-viscosity oil is supplied to the gear chamber 30a, the losses are not too high. Additionally, when the oil flows from the connection port 76a-2 towards the connection port 76a-1 within the internal flow path 76a, the cooling performance of the oil cooler 76 is lower compared to the case of reverse oil flow. Therefore, in the second operation, the cooling performance of the oil cooler 76 is low, and the viscosity of the oil supplied to the gear chamber 30a is not too high. Consequently, the losses occurring in the gear chamber 30a are reduced further in the second operation. Thus, the motor unit 16 can operate efficiently in the second operation.

[0045] As explained above, in the motor unit 16, during the first and second operations, oil flows in opposite directions through the internal flow path 76a of the oil cooler 76. That is, the motor unit 16 allows bidirectional flow of oil through the internal flow path 76a of the oil cooler 76. According to this structure, there is no need to provide a flow path that bypasses the oil cooler 76, thus enabling the motor unit 16 to be miniaturized. For example, if it is desired to supply oil from the motor chamber flow path 72b to the gear chamber oil supply port 21 in the second operation, bypassing the oil cooler 76, then... Figure 5 The bypass flow path 100 is set up in that way. In this case, the bypass flow path 100 needs to intersect with other flow paths, resulting in a large motor unit. In contrast, in the motor unit 16 of this embodiment, a bypass flow path is not required, thus enabling the realization of a small motor unit 16.

[0046] In addition, such as Figure 4As shown, the motor chamber oil supply port 23 and the gear chamber oil supply port 21 are arranged at a distance from each other in the vehicle width direction. The oil cooler 76 has a shape that is longer in the vehicle width direction. The connection ports 76a-1 and 76a-2 of the internal flow path 76a of the oil cooler 76 are arranged at a distance from each other in the vehicle width direction. The connection ports 76a-1 and 76a-2 are arranged with the connection port 76a-1 located closer to the gear chamber oil supply port 21 than the connection port 76a-2. The connection ports 76a-1 and 76a-2 are arranged between the motor chamber oil supply port 23 and the gear chamber oil supply port 21 in the vehicle width direction. According to this structure, the flow path connecting the connection port 76a-1 to the gear chamber oil supply port 21 and the flow path connecting the connection port 76a-2 to the motor chamber oil supply port 23 can be shortened, and the motor unit 16 can be made smaller.

[0047] The embodiments have been described in detail above, but these are merely illustrative and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples illustrated above. The technical elements described in this specification or drawings, individually or in various combinations, contribute to the technical utility and are not limited to the combinations described in the claims at the time of application. Furthermore, the technology illustrated in this specification or drawings can achieve multiple objectives simultaneously, and achieving even one of these objectives is itself technically practical.

Claims

1. A motor unit, wherein, The motor unit has: The housing contains a motor chamber and a gear chamber; The motor is located in the motor housing; A gear, disposed within the gear chamber, engages with the rotating shaft of the motor; and An oil supply device supplies oil to the motor chamber and the gear chamber. The oil supply device has: Oil pump; Oil cooler; A first oil flow path is provided with a first valve, configured to allow oil supplied from the oil pump to flow when the first valve is open, and connecting the oil pump, the oil supply port of the gear chamber, and the first end of the internal flow path of the oil cooler; and The second oil flow path is provided with a second valve, configured to allow oil supplied from the oil pump to flow when the second valve is open, and to connect the oil pump, the oil supply port of the motor chamber, and the second end of the internal flow path.

2. The motor unit according to claim 1, wherein, Compared to the case where oil flows from the second end to the first end in the internal flow path, the oil cooler has higher cooling performance when the oil flows from the first end to the second end in the internal flow path.

3. The motor unit according to claim 1 or 2, wherein, The motor unit is mounted on the vehicle. The oil supply port of the motor chamber and the oil supply port of the gear chamber are arranged at intervals in the vehicle width direction. The oil cooler has a shape that is relatively long in the vehicle width direction. The first end and the second end are disposed in the vehicle width direction between the oil supply port of the motor chamber and the oil supply port of the gear chamber, with the first end positioned closer to the oil supply port of the gear chamber than the second end.

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