Motor unit

Abstract

In the motor unit, it is possible to supply oil that is not cooled by the oil cooler to the motor chamber, and the motor unit can be made smaller. [Solution] A motor unit comprising a case and an oil supply device that supplies oil to a motor chamber and a gear chamber within the case. The oil supply device comprises an oil pump, an oil cooler, a first oil passage, and a second oil passage. The first oil passage is configured to allow oil supplied from the oil pump to flow when the first valve is open, and is a passage connecting the oil pump, the oil supply port of the gear chamber, and the first end of the internal passage of the oil cooler. The second oil passage is configured to allow oil supplied from the oil pump to flow when the second valve is open, and is a passage connecting the oil pump, the oil supply port of the motor chamber, and the second end of the internal passage.

Description

Technical Field

[0001] The technology disclosed in this specification relates to a motor unit.

[0002] In the motor unit disclosed in Patent Document 1, a motor chamber and a gear chamber are provided in a case. A motor is provided in the motor chamber, and a gear is provided in the gear chamber. Further, this motor unit has an oil cooler for cooling oil. The oil cooled by the oil cooler is supplied into the case. Thereby, the motor unit is cooled.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the temperature of the oil is low, the viscosity of the oil becomes high. When the temperature of the motor is low and the oil cooled by the oil cooler is supplied to the motor chamber, the efficiency of the motor decreases. In this specification, a technique is proposed that enables the supply of oil not cooled by the oil cooler to the motor chamber in a motor unit and downsizes the motor unit.

Means for Solving the Problems

[0005] A motor unit disclosed herein comprises a case having a motor chamber and a gear chamber, a motor disposed in the motor chamber, a gear disposed in the gear chamber and engaged with the rotation shaft of the motor, and an oil supply device for supplying oil to the motor chamber and the gear chamber. The oil supply device comprises an oil pump, an oil cooler, a first oil passage, and a second oil passage. The first oil passage is provided with a first valve and configured to allow oil supplied from the oil pump to flow when the first valve is open, and is a passage connecting the oil pump, the oil supply port of the gear chamber, and the first end of the internal passage of the oil cooler. The second oil passage is provided with a second valve and configured to allow oil supplied from the oil pump to flow when the second valve is open, and is a passage connecting the oil pump, the oil supply port of the motor chamber, and the second end of the internal passage.

[0006] This motor unit can perform a first operation with the first valve open and a second operation with the second valve open. In the first operation, oil is supplied to the gear chamber and the oil cooler via the first oil passage. The oil that has passed through the oil cooler (i.e., the internal passage) from the first end to the second end is supplied to the motor chamber via the second oil passage. Thus, in the first operation, oil is supplied to both the motor chamber and the gear chamber. In this case, the cooler oil that has passed through the oil cooler is supplied to the motor chamber. In the second operation, oil is supplied to the motor chamber and the oil cooler via the second oil passage. The oil that has passed through the oil cooler (i.e., the internal passage) from the second end to the first end is supplied to the gear chamber via the first oil passage. Thus, in the second operation as well, oil is supplied to both the motor chamber and the gear chamber. In this case, the relatively hotter oil that has not passed through the oil cooler is supplied to the motor chamber. As explained above, this configuration allows switching between a first operation in which oil that has passed through the oil cooler is supplied to the motor chamber, and a second operation in which oil that has not passed through the oil cooler is supplied to the motor chamber. Furthermore, in this configuration, oil flows to the oil cooler in both directions during the first and second operations, so there is no need to provide a bypass passage for the oil cooler. Therefore, the motor unit can be made smaller. [Brief explanation of the drawing]

[0007] [Figure 1] A side view of the vehicle. [Figure 2] Perspective view of motor unit 16. [Figure 3] A cross-sectional view showing the internal structure of case 20. [Figure 4] A diagram showing the flow path of the oil supply device 70. [Figure 5] A diagram showing the bypass flow path 100 of the comparative example oil supply device 70. [Modes for carrying out the invention]

[0008] In one example of a motor unit disclosed herein, the cooling performance of the oil cooler may be higher when oil flows through the internal passage from the first end to the second end than when oil flows through the internal passage from the second end to the first end.

[0009] This configuration allows low-viscosity oil to be supplied to the gear chamber during the second operation.

[0010] In one example of a motor unit disclosed herein, the motor unit may be mounted on a vehicle. The oil supply port of the motor chamber and the oil supply port of the gear chamber may be spaced apart in the vehicle width direction. The oil cooler may have a shape that is elongated in the vehicle width direction. The first end and the second end may be positioned between the oil supply port of the motor chamber and the oil supply port of the gear chamber in the vehicle width direction such that the first end is positioned closer to the oil supply port of the gear chamber than the second end.

[0011] This configuration allows for shortening the flow path between the motor chamber and the second end, and the flow path between the gear chamber and the first end.

[0012] The vehicle 10 shown in Figure 1 is a vehicle having an electric motor as at least one of its drive sources. The vehicle 10 may be, for example, an electric vehicle, a hybrid vehicle, or a fuel cell vehicle.

[0013] Vehicle 10 has a battery pack 12 mounted under the floor and two motor units 16 and 18. The battery pack 12 supplies power to each of the motor units 16 and 18. Motor unit 16 drives the front wheels 13, and motor unit 18 drives the rear wheels 14. Although vehicle 10 is exemplified as a four-wheel drive vehicle, it may also be a two-wheel drive vehicle equipped with only one of the motor units 16 or 18. Motor units 16 and 18 have a common structure. Motor unit 16 will be described below.

[0014] As shown in Figure 2, the motor unit 16 comprises a case 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 case 20. The power control unit 19 is positioned adjacent to the motor 60 and gear mechanism 30 in the longitudinal direction of the vehicle (rear in this example). The power control unit 19 converts the power supplied from the battery pack 12 from DC to 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 into torque and then distributes it to the left and right wheels.

[0015] As shown in Figure 3, the case 20 contains a motor chamber 60a housing the motor 60 and a gear chamber 30a housing the gear mechanism 30. The motor chamber 60a and the gear chamber 30a are connected to each other.

[0016] The motor 60 comprises a stator 62 and a rotor 64. The stator 62 is fixed to the case 20. The rotor 64 is positioned concentrically inside the stator 62. The rotor 64 is supported by the case 20 so as to be rotatable around its central axis. The output shaft 66 of the rotor 64 is hollow. That is, the output shaft 66 is provided with a through hole 66a extending along its central axis.

[0017] The gear mechanism 30 comprises 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. Note that the configuration of the gear mechanism 30 described below is just one example, and other types of configurations can be adopted as appropriate.

[0018] The planetary gear mechanism 40 includes a sun gear 42, a plurality of stepped pinion gears 44, a ring gear 46, and a 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 plurality of stepped pinion gears 44 has a large-diameter pinion gear P1 and a small-diameter pinion gear P2 that is smaller in diameter than the large-diameter pinion gear P1. The large-diameter pinion gear P1 meshes with the sun gear 42. The small-diameter pinion gear P2 meshes with the ring gear 46. The ring gear 46 is fixed to the case 20. The carrier 48 rotatably supports each of the plurality of stepped pinion gears 44. Thus, in the planetary gear mechanism 40, the sun gear 42 is an input element, the ring gear 46 is a reaction force element, and the carrier 48 is an output element.

[0019] The differential gear 50 includes a differential case 51. The differential case 51 is supported by the case 20 so as to be rotatable around the rotation axis of the motor 60. The differential case 51 is connected to the carrier 48 of the planetary gear mechanism 40 and rotates integrally with the carrier 48.

[0020] Inside the differential case 51, a pinion shaft 53, a pair of differential pinion gears 54, 55, and side gears 56, 57 are provided.

[0021] The pinion shaft 53 is connected to the differential case 51 and rotates integrally with the differential case 51. The pinion shaft 53 extends inside the differential case 51 along a direction orthogonal to the rotation axis direction of the motor 60. Each of the pair of differential pinion gears 54, 55 is supported by the pinion shaft 53 so as to be rotatable around the axis of the pinion shaft 53. The side gear 56 is a member that outputs driving force to the front wheel 13a and meshes with each of the pair of differential pinion gears 54, 55. The side gear 57 is a member that outputs driving force to the front wheel 13b and meshes with each of the pair of differential pinion gears 54, 55.

[0022] The motor unit 16 further includes drive shafts 58 and 59. The drive shaft 58 is inserted into the through-hole 66a of the output shaft 66. The drive shaft 58 connects the side gear 56 and the front wheel 13a. The drive shaft 59 connects the side gear 57 and the front wheel 13b. The drive shafts 58 and 59 transmit the driving force from the differential gear 50 to the left and right front wheels 13a and 13b.

[0023] Lubricating oil is stored at the bottom of the case 20. The case 20 is provided with an oil discharge port 24, motor chamber oil supply ports 22 and 23, and a gear chamber oil supply port 21. The oil discharge port 24 is provided at the bottom of the case 20. The oil discharge port 24 discharges the oil stored in the case 20 to the outside of the case 20. Oil is supplied to the motor chamber oil supply ports 22, 23 and the gear chamber oil supply port 21 from the outside. The motor chamber oil supply ports 22 and 23 are provided at the upper part of the motor chamber 60a. The motor chamber oil supply port 22 discharges the oil supplied from the outside toward the stator 62. The motor chamber oil supply port 23 is connected to a cooling flow path 62a provided inside the stator 62. The oil supplied from the outside to the motor chamber oil supply port 23 flows in the cooling flow path 62a. The oil that has passed through the cooling flow path 62a is discharged into the motor chamber 60a. The gear chamber oil supply port 21 is provided at the upper part of the gear chamber 30a. The gear chamber oil supply port 21 discharges the oil supplied from the outside toward the gears in the gear chamber 30a.

[0024] Figure 4 is a view of the front compartment 11 of the vehicle 10 from above. As shown in Figure 4, the case 20 is located inside the front compartment 11. The motor unit 16 also has an oil supply device 70. The oil supply device 70 supplies oil into the case 20. The oil supply device 70 has an oil pump 74 and an oil cooler 76. The oil cooler 76 has an internal passage 76a through which oil flows. The internal passage 76a has connection ports 76a-1 and 76a-2 at both ends. The oil cooler 76 cools the oil flowing through the internal passage 76a by heat exchange. The oil pump 74 and the oil cooler 76 are located at the top of the case 20.

[0025] As shown in Figure 4, the oil supply device 70 has a first oil passage 71 and a second oil passage 72 located at the top of the case 20. Also, as shown in Figure 3, the oil supply device 70 has an oil discharge passage 75 connected to the bottom of the case 20.

[0026] As shown in Figure 3, the upstream end of the oil discharge passage 75 is connected to an oil outlet 24 located on the bottom of the case 20. The downstream end of the oil discharge passage 75 is connected to the suction port of the oil pump 74. The oil pump 74 sucks the oil accumulated at the bottom of the case 20 through the oil discharge passage 75.

[0027] As shown in Figure 4, the discharge port of the oil pump 74 is connected to a first oil passage 71 and a second oil passage 72. The oil pump 74 sends the oil drawn in from the oil discharge passage 75 to the first oil passage 71 and the second oil passage 72.

[0028] The first oil passage 71 connects the oil pump 74, the gear chamber oil supply port 21, and the connection port 76a-1 of the oil cooler 76 to each other. The first oil passage 71 has a pump passage 71a, a gear chamber passage 71b, and an oil cooler passage 71c. The upstream end of the pump passage 71a is connected to the discharge port of the oil pump 74. A valve 77 is provided in the pump passage 71a. The valve 77 opens and closes the pump passage 71a. The downstream end of the pump passage 71a is connected to the upstream end of the gear chamber passage 71b and the upstream end of the oil cooler passage 71c. The downstream end of the gear chamber passage 71b is connected to the gear chamber oil supply port 21. The downstream end of the oil cooler passage 71c is connected to the connection port 76a-1.

[0029] The second oil passage 72 connects the oil pump 74, the motor room oil supply ports 22 and 23, and the connection ports 76a-2 of the oil cooler 76. The second oil passage 72 has a pump passage 72a and a motor room passage 72b. The upstream end of the pump passage 72a is connected to the discharge port of the oil pump 74. A valve 78 is provided in the pump passage 72a. The valve 78 opens and closes the pump passage 72a. The downstream end of the pump passage 72a is connected to the upstream end of the motor room passage 72b and the connection ports 76a-2 of the oil cooler 76. The downstream part of the motor room passage 72b is branched into two. One downstream end of the motor room passage 72b is connected to the motor room oil supply port 22. The other downstream end of the motor room passage 72b is connected to the motor room oil supply port 23. The oil supply device 70 has a control device (not shown) that controls the oil pump 74 and valves 77 and 78.

[0030] The oil supply device 70 supplies oil into the case 20 while the motor 60 is in operation. The oil supplied into the case 20 lubricates and cools the motor 60 and gears. The oil supply device 70 can also perform a first operation, which is to supply oil cooled by the oil cooler 76 to the motor chamber 60a, and a second operation, which is to supply oil that has not been 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 the like, and performs the first and second operations according to the detected temperature.

[0031] If the temperature of the motor 60 is higher than the standard value, the oil supply device 70 performs a first action. In the first action, the oil supply device 70 opens valve 77, closes valve 78, and operates the oil pump 74. As a result, the oil pump 74 discharges oil into the pump passage 71a. The oil in the pump passage 71a then branches and flows into the gear chamber passage 71b and the oil cooler passage 71c.

[0032] The oil in the gear chamber passage 71b is discharged from the gear chamber oil supply port 21 toward the gears in the gear chamber 30a. This lubricates the gears in the gear chamber 30a.

[0033] The oil in the oil cooler passage 71c flows into the internal passage 76a from connection port 76a-1. The oil flowing in the internal passage 76a is cooled by the oil cooler 76. The oil in the internal passage 76a flows into the motor chamber passage 72b from connection port 76a-2. The oil in the motor chamber passage 72b is supplied into the motor chamber 60a from motor chamber oil supply ports 22 and 23. The oil supplied into the motor chamber 60a from motor chamber oil supply port 22 flows into the cooling passage 62a of the stator 62. The stator 62 is cooled by the flow of oil in the cooling passage 62a. The oil that has flowed through the cooling passage 62a is discharged into the motor chamber 60a. In addition, the motor chamber oil supply port 23 discharges oil toward the stator 62. This also cools the stator 62. Furthermore, the motor 60 is lubricated by the oil discharged into the motor chamber 60a.

[0034] As explained above, in the first operation, which is performed when the motor 60 is hot, oil cooled by the oil cooler 76 is supplied into the motor chamber 60a. The oil cooler 76 can efficiently cool the oil as it flows through the internal passage 76a from connection port 76a-1 to connection port 76a-2. Therefore, in the first operation, sufficiently cool oil is supplied into the motor chamber 60a. As a result, the motor 60 can be cooled efficiently.

[0035] If the temperature of the motor 60 is below the reference value, the oil supply device 70 performs a second action. In the second action, the oil supply device 70 closes valve 77, opens valve 78, and operates the oil pump 74. As a result, the oil pump 74 discharges oil into the pump passage 72a. The oil in the pump passage 72a then branches off and flows to the motor chamber passage 72b and the connection port 76a-2.

[0036] The oil in the motor chamber passage 72b is supplied into the motor chamber 60a from the motor chamber oil supply ports 22 and 23. The stator 62 is cooled as the oil flows from the motor chamber oil supply port 22 into the cooling passage 62a of the stator 62. In addition, the motor chamber oil supply port 23 discharges oil toward the stator 62. This also cools the stator 62. Furthermore, the motor 60 is lubricated by the oil discharged into the motor chamber 60a.

[0037] The oil that flows from the pump passage 72a to the connection port 76a-2 flows into the internal passage 76a from the connection port 76a-2. The oil flowing in the internal passage 76a is cooled by the oil cooler 76. The oil in the internal passage 76a flows from the connection port 76a-1 through the oil cooler passage 71c to the gear chamber passage 71b. The oil in the gear chamber passage 71b is discharged from the gear chamber oil supply port 21 toward the gears in the gear chamber 30a. This lubricates the gears in the gear chamber 30a.

[0038] As explained above, in the second operation, which is 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 into the motor chamber 60a. Since the temperature of the oil supplied into the motor chamber 60a is relatively high, the viscosity of the oil supplied into the motor chamber 60a is low. Therefore, losses due to oil viscosity are less likely to occur in the motor 60, and the motor 60 can operate efficiently. Thus, when the temperature of the motor 60 is sufficiently low, the operation efficiency of the motor 60 is improved by supplying relatively high-temperature oil into the motor chamber 60a. In addition, in the second operation, oil cooled by the oil cooler 76 is supplied to the gear chamber 30a, but since gears are less affected by oil viscosity than the motor 60, the losses are not so high even if high-viscosity oil is supplied to the gear chamber 30a. Furthermore, when oil flows through the internal passage 76a from connection port 76a-2 to connection port 76a-1, the cooling performance of the oil cooler 76 is lower compared to when oil flows in the reverse direction. 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 very high. As a result, the losses that occur in the gear chamber 30a during the second operation are further reduced. In this way, the motor unit 16 can operate efficiently during the second operation.

[0039] As explained above, in the motor unit 16, oil flows in opposite directions through the internal passage 76a of the oil cooler 76 during the first and second operations. In other words, the motor unit 16 allows oil to flow in both directions through the internal passage 76a of the oil cooler 76. With this configuration, there is no need to provide a bypass passage for the oil cooler 76, so the motor unit 16 can be made smaller. For example, if it were to supply oil to the gear chamber oil supply port 21 by bypassing the oil cooler 76 from the motor chamber passage 72b during the second operation, it would be necessary to provide a bypass passage 100 as shown in Figure 5. In this case, a three-dimensional intersection between the bypass passage 100 and other passages would be necessary, resulting in a larger motor unit. In contrast, the motor unit 16 of this embodiment does not require a bypass passage, so a smaller motor unit 16 can be realized.

[0040] Furthermore, as shown in Figure 4, the motor chamber oil supply port 23 and the gear chamber oil supply port 21 are spaced apart in the vehicle width direction. The oil cooler 76 has a long shape 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 spaced apart in the vehicle width direction. The connection ports 76a-1 and 76a-2 are arranged such that connection port 76a-1 is closer to the gear chamber oil supply port 21 than connection port 76a-2. In the vehicle width direction, connection ports 76a-1 and 76a-2 are located between the motor chamber oil supply port 23 and the gear chamber oil supply port 21. With this configuration, the flow path connecting connection port 76a-1 and the gear chamber oil supply port 21, and the flow path connecting connection port 76a-2 and the motor chamber oil supply port 23 can be shortened, and the motor unit 16 can be made smaller.

[0041] Although embodiments have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. The technical elements described in this specification or drawings exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated in this specification or drawings achieve multiple objectives simultaneously, and achieving even one of these objectives constitutes technical usefulness. [Explanation of symbols]

[0042] 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

Claims

1. A motor unit, A case having a motor room and a gear room, A motor located inside the motor chamber, A gear is located inside the gear chamber and engages with the rotating shaft of the motor, An oil supply device that supplies oil to the motor chamber and the gear chamber, It has, The oil supply device, oil pump and oil cooler and A first valve is provided, and when the first valve is opened, oil supplied from the oil pump flows through it. A first oil passage connects the oil pump, the oil supply port of the gear chamber, and the first end of the internal passage of the oil cooler. A second valve is provided, and when the second valve is open, oil supplied from the oil pump flows through it. A second oil passage connects the oil pump, the oil supply port of the motor chamber, and the second end of the internal passage. A motor unit having the following features.

2. The motor unit according to claim 1, wherein when oil flows through the internal passage from the first end to the second end, the cooling performance of the oil cooler is higher than when oil flows through the internal passage from the second end to the first end.

3. 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 with a gap between them in the vehicle width direction. The aforementioned oil cooler has a shape that is elongated in the vehicle width direction, The first end and the second end are positioned between the oil supply port of the motor chamber and the oil supply port of the gear chamber, such that in the vehicle width direction, the first end is positioned closer to the oil supply port of the gear chamber than the second end. The motor unit according to claim 1 or 2.

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