Electric vehicle transmission

Abstract

An electric vehicle transmission (30) for a vehicle includes a housing (32) defining a housing interior (34) and an electric motor (40) disposed in the housing interior (34). The electric motor (40) includes a rotor (42) and a stator (44). The electric vehicle transmission (30) also includes an input shaft (46) disposed in the housing interior (34) and extending along an axis of the shaft. The input shaft (46) is rotatably coupled to a rotor (42) of an electric motor (40). The electric vehicle transmission (30) further includes a gear reduction assembly (50) disposed in the housing interior (34). A gear reduction assembly (50) is rotatably coupled to the input shaft (46) for transmitting rotational torque to wheels of the vehicle. The housing (32) defines a first reservoir (36) for containing oil and a second reservoir (38) separate from the first reservoir (36) for containing oil. The second reservoir (38) and the first reservoir (36) are configured such that oil lubricates the gear reduction assembly (50) when flowing from the second reservoir (38) into the first reservoir (36).

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to and all advantages of U.S. Provisional Patent Application No. 63 / 342,738, filed on May 17, 2022, the entire contents of which are hereby incorporated by reference. Technical Field

[0002] The present invention generally relates to electric vehicle transmissions. Background Art

[0003] A conventional electric vehicle transmission for a vehicle includes: a housing defining an interior of the housing and a sump for containing oil; an electric motor including a rotor and a stator disposed in the interior of the housing; an input shaft disposed in the interior of the housing and extending along a shaft axis, wherein the shaft is rotatably coupled to the rotor of the electric motor; and a gear reduction assembly disposed in the interior of the housing. The gear reduction assembly is rotatably coupled to the input shaft for transmitting a rotational torque to the wheels of the vehicle. The oil is typically distributed from the sump to the entire electric vehicle transmission using at least one pump. However, a typical electric vehicle transmission uses at least one pump to distribute the oil to the entire electric vehicle transmission, requiring at least one pump to be larger, which takes up space in the vehicle and increases the cost of the electric vehicle components.

[0004] Therefore, there remains a need for improved electric vehicle transmissions. Summary of the invention

[0005] An electric vehicle transmission for a vehicle, comprising: a housing defining an interior of the housing and an electric motor disposed in the interior of the housing. The electric motor comprises a rotor and a stator. The electric vehicle transmission also comprises an input shaft disposed in the interior of the housing and extending along the axis of the shaft. The input shaft is rotatably coupled to the rotor of the electric motor. The electric vehicle transmission further comprises a gear reduction assembly disposed in the interior of the housing. The gear reduction assembly is rotatably coupled to the input shaft for transmitting a rotational torque to the wheels of the vehicle. The housing defines a first reservoir for containing oil and a second reservoir for containing oil separated from the first reservoir. The second reservoir and the first reservoir are configured such that: the oil lubricates the gear reduction assembly when it flows from the second reservoir into the first reservoir. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Other advantages of the present disclosure will be readily appreciated as the disclosure becomes better understood by referring to the following detailed description when considered in conjunction with the accompanying drawings.

[0007] Figure 1 is a perspective view of an electric vehicle transmission including a housing defining a housing interior; Figure 2is a perspective view of the gear reduction assembly; Figure 3 is a front view of the gear reduction assembly; Figure 4 is a front view of an electric vehicle transmission, the electric vehicle transmission including a housing defining a first reservoir and a second reservoir; Figure 5 is a perspective view of a transmission for an electric vehicle; Figure 6 is a perspective view of a transmission for an electric vehicle; Figure 7 is a front view of a planetary gear set and carrier of an electric vehicle transmission; Figure 8 is a front view of another embodiment of a planetary gear set and a carrier of an electric vehicle transmission; Fig. 9 is a front view of another embodiment of a planetary gear set and a carrier of an electric vehicle transmission; Fig.10 is a cross-sectional view of an electric vehicle transmission, wherein the interior of the housing has a motor side and a gear reduction side; and Fig.11 is an exploded perspective view of the gear reduction assembly. DETAILED DESCRIPTION

[0008] Referring to the drawings, wherein like numerals refer to like parts throughout the several views, Figure 1-11 , an electric vehicle transmission 30 for a vehicle is generally shown. The electric vehicle transmission 30 includes a housing 32 that defines a housing interior 34. The electric vehicle transmission also includes an electric motor 40 that is disposed in the housing interior 34. The electric motor 40 includes a rotor 42 and a stator 44. The electric vehicle transmission 30 further includes an input shaft 46 that is disposed in the housing interior 34 and extends along a shaft axis SA. The input shaft 46 is rotatably coupled to the rotor 42 of the electric motor 40. The electric vehicle transmission 30 typically includes a first output shaft 47 and a second output shaft 49. The input shaft 46 and the first output shaft 47 may be concentric shafts. The electric vehicle transmission 30 additionally includes a gear reduction assembly 50 that is disposed in the housing interior 34. The gear reduction assembly 50 is rotatably coupled to the input shaft 46 for transmitting a rotational torque to the wheels of the vehicle.

[0009] The housing 32 defines a first reservoir 36 for containing oil and a second reservoir 38 for containing oil separate from the first reservoir 36. The housing 32 may include a housing protrusion 56 extending into the second reservoir 38 for further defining the second reservoir 38. The second reservoir 38 and the first reservoir 36 are configured so that the oil lubricates the gear reduction assembly 50 when it flows from the second reservoir 38 into the first reservoir 36. As described in further detail below, by configuring the second reservoir 38 and the first reservoir 36 so that the oil lubricates the gear reduction assembly 50 when it flows from the second reservoir 38 into the first reservoir 36, the electric vehicle transmission 30 is allowed to use a smaller pump to lubricate the motor 40. In addition, as described in further detail below, by configuring the second reservoir 38 and the first reservoir 36 so that the oil lubricates the gear reduction assembly 50 when it flows from the second reservoir 38 into the first reservoir 36, the lubrication of the gear reduction assembly 50 is allowed to depend on the rotational speed of the components of the electric vehicle transmission 30.

[0010] In one embodiment, the second reservoir 38 and the first reservoir 36 are configured to passively control the flow of oil from the second reservoir 38 and the first reservoir 36. In other words, the electric vehicle transmission 30 may not have a valve (such as a solenoid valve) for actively controlling the flow of oil between the second reservoir 38 and the first reservoir 36. Typically, the oil flows from the second reservoir 38 to the first reservoir 36 by gravity. In order to control the amount of oil flowing from the second reservoir 38 to the first reservoir 36, an oil passage 58 may be defined between the second reservoir 38 and the first reservoir 36, wherein the flow area of ​​the oil passage 58 is sized based on the desired flow rate of oil flowing from the second reservoir 38 to the first reservoir 36. Typically, the amount of oil flowing through the oil passage 58 is less than the amount of oil scooped from the first reservoir 36 to the second reservoir 38. Alternatively, the electric vehicle transmission 30 may include a valve 60 , such as a solenoid valve, disposed between the second reservoir 38 and the first reservoir to actively control the flow of oil between the second reservoir 38 and the first reservoir 36 .

[0011] The gear reduction assembly 50 may be further defined as a planetary gear set 62. The planetary gear set 62 may include a plurality of pinion gears 64 disposed about the shaft axis SA. The plurality of pinion gears 64 may be defined as three pinion gears 64 and may be radially separated from each other by 120 degrees about the shaft axis SA.

[0012] The electric vehicle transmission 30 may include a carrier 66, such as a disc, coupled to the gear reduction assembly 50. When present, the carrier 66 is configured to scoop (i.e., transfer) oil from the first reservoir 36 to the second reservoir 38 during rotation of the gear reduction assembly 50. In one embodiment, the carrier 66 has a circular configuration. The carrier 66 may have a first carrier surface 68 and a second carrier surface 70, the first carrier surface 68 facing a first direction relative to the axis SA of the shaft, and the second carrier surface 70 facing a second direction opposite to the first direction relative to the axis SA of the shaft. The first carrier surface 68 and the second carrier surface 70 may have a flat configuration. Having a flat configuration allows the carrier 66 to rotate through the oil in the first reservoir with minimal drag loss, all while still allowing the oil to be set on the first carrier surface 68 and the second carrier surface 70 and transferred to the second reservoir 38 due to the rotation of the carrier 66. The first carrier surface 68 and the second carrier surface 70 may be parallel to each other. It will be appreciated that the first carrier surface 68 and the second carrier surface 70 may have protrusions and / or recesses for assisting in scooping oil from the first reservoir 36 to the second reservoir 38 during rotation of the carrier 66. Whether the first carrier surface 68 and the second carrier surface 70 are flat or have recesses and / or protrusions depends on the trade-off between the desire to reduce the resistance of the carrier 66 through the oil in the first reservoir 36 and the amount of oil that needs to be scooped from the first reservoir 36 to the second reservoir 38.

[0013] The pinion 64 may define a pinion diameter PD. The carrier 66 may define a carrier diameter CD. Typically, the carrier diameter CD is greater than the pinion diameter PD. It will be appreciated that the carrier 66 may have an enlarged diameter portion to further allow the carrier 66 to enter the oil disposed in the first reservoir 36 during rotation of the carrier 66 so as to then scoop the oil out into the second reservoir 38. In addition to being configured to scoop oil out of the first reservoir 36 to the second reservoir 38, the carrier 66 also provides additional support for the pinion 64, so that deflection of components of the electric vehicle transmission 30, particularly the gear reduction assembly 50, is reduced. To this end, when the carrier 66 is present, the carrier 66 is able to move oil from the first reservoir 36 to the second reservoir 38 and reduce spin losses of the electric vehicle transmission 30.

[0014] like Fig.10, the housing interior 34 can be divided into a motor side 74 and a gear reduction side 76. Typically, the electric vehicle transmission 30 includes a pump for circulating oil in the motor side 74 of the housing interior 34. The electric vehicle transmission 30 may not have a pump for circulating oil in the gear reduction side 76 of the housing interior 34. Due to the need to cool the motor 40, the motor side 74 of the housing interior 34 typically requires a higher flow and circulation of oil to cool the motor 40. The pump circulates the oil and cools the oil through the heat exchanger of the electric vehicle transmission 30. When the carrier 66 is present, the gear reduction side 76 of the housing interior 34 typically does not require a pump because the carrier 66 scoops the oil from the first reservoir 36 to the second reservoir 38 and allows gravity to pull the oil from the second reservoir 38 to the first reservoir 36 and lubricate the gear reduction assembly 50. To help direct the oil throughout the gear reduction assembly 50 and to other components of the electric vehicle transmission 30, the electric vehicle transmission 30 may include an oil distribution assembly 78 disposed within the housing interior 34. Typically, the oil distribution assembly 78 is disposed between the second reservoir 38 and the first reservoir 36 such that the oil flows from the second reservoir 38 to the oil distribution assembly 78 and, after the oil lubricates the gear reduction assembly 50 and other components of the electric vehicle transmission 30, such as bearings, gears, and bushings, flows to the first reservoir 36.

[0015] In order to balance the amount of oil in the motor side 74 and the gear reduction side 76 inside the housing, the housing 32 may define an upper overfill bleed orifice 82 in the second reservoir 38 for allowing oil to flow between the motor side 74 and the gear reduction side 76. Similarly, the housing 32 may define a lower overfill bleed orifice 82 in the first reservoir 36 for allowing oil to flow between the motor side 74 and the gear reduction side 76.

[0016] Embodiment 1: An electric vehicle transmission for a vehicle, comprising: a housing defining a housing interior; an electric motor disposed inside the housing, wherein the electric motor comprises a rotor and a stator; an input shaft disposed within the housing interior and extending along a shaft axis, wherein the input shaft is rotatably coupled to the rotor of the electric motor; a gear reduction assembly disposed within the housing interior, wherein the gear reduction assembly is rotatably coupled to the input shaft for transmitting rotational torque to wheels of the vehicle; wherein the housing defines a first reservoir for containing oil and a second reservoir for containing oil separated from the first reservoir; Wherein, the second reservoir and the first reservoir are configured such that oil lubricates the gear reduction assembly when flowing from the second reservoir into the first reservoir.

[0017] Embodiment 2: The electric vehicle transmission as set forth in Embodiment 1, wherein the second reservoir and the first reservoir are configured to passively control oil flow between the second reservoir and the first reservoir.

[0018] Embodiment 3: The electric vehicle transmission as set forth in Embodiment 1, further comprising a valve disposed between the second reservoir and the first reservoir to actively control the flow of oil between the second reservoir and the first reservoir.

[0019] Embodiment 4: The electric vehicle transmission as set forth in any of the preceding embodiments, wherein the gear reduction assembly is further defined as a planetary gear set.

[0020] Embodiment 5: The electric vehicle transmission as set forth in Embodiment 4, wherein the planetary gear set includes a plurality of pinion gears disposed about the axis of the shaft.

[0021] Embodiment 6: The electric vehicle transmission as set forth in Embodiment 5, wherein the plurality of pinions are further defined as three pinions.

[0022] Embodiment 7: The electric vehicle transmission as set forth in Embodiment 6, wherein the three pinions are radially separated from each other by 120 degrees around the axis of the shaft.

[0023] Embodiment 8: The electric vehicle transmission as set forth in any of the preceding embodiments, further comprising a carrier coupled to the gear reduction assembly, wherein the carrier is configured to scoop oil from the first reservoir to the second reservoir during rotation of the gear reduction assembly.

[0024] Embodiment 9: The electric vehicle transmission as set forth in Embodiment 8, wherein the carrier has a circular configuration.

[0025] Embodiment 10: An electric vehicle transmission according to any one of embodiments 8 and 9, wherein the carrier has a first carrier surface and a second carrier surface, the first carrier surface faces a first direction relative to the axis of the shaft, and the second carrier surface faces a second direction opposite to the first direction relative to the axis of the shaft, wherein the first carrier surface and the second carrier surface have a flat structure.

[0026] Embodiment 11: An electric vehicle transmission according to any one of embodiments 8 and 9, wherein the carrier has a first carrier surface and a second carrier surface, the first carrier surface faces a first direction relative to the axis of the shaft, and the second carrier surface faces a second direction opposite to the first direction relative to the axis of the shaft, wherein the first carrier surface and the second carrier surface have protrusions and / or recesses.

[0027] Embodiment 12: An electric vehicle transmission according to any one of embodiments 8 and 9, wherein the carrier has a first carrier surface and a second carrier surface, the first carrier surface faces a first direction relative to the axis of the shaft, and the second carrier surface faces a second direction opposite to the first direction relative to the axis of the shaft, wherein at least one of the first carrier surface and the second carrier surface has a protrusion and / or a recess for assisting in scooping oil from the first reservoir to the second reservoir during rotation of the carrier.

[0028] Embodiment 13: The electric vehicle transmission as set forth in any one of the preceding embodiments, wherein the housing includes a housing protrusion extending into the second reservoir to further define the second reservoir.

[0029] Embodiment 14: The electric vehicle transmission as set forth in any one of the preceding embodiments, wherein the interior of the housing is divided into a motor side and a gear reduction side.

[0030] Embodiment 15: The electric vehicle transmission as set forth in Embodiment 14, wherein the housing defines an upper overflow drain port in the second reservoir for allowing oil to flow between the motor side and the gear reduction side.

[0031] Embodiment 16: The electric vehicle transmission as set forth in any one of Embodiments 14 and 15, wherein the housing defines a lower overflow drain port in the first reservoir for allowing oil to flow between the motor side and the gear reduction side.

[0032] Embodiment 17: The electric vehicle transmission as set forth in any one of Embodiments 14 to 16, further comprising a pump for circulating oil in the motor side inside the housing.

[0033] Embodiment 18: The electric vehicle transmission as set forth in any one of Embodiments 14 to 17, without a pump for circulating oil in the gear reduction side inside the housing.

[0034] Embodiment 19: The electric vehicle transmission as set forth in any of the preceding embodiments, further comprising an oil distribution assembly disposed within the housing interior.

[0035] Embodiment 20: The electric vehicle transmission according to embodiment 19, wherein the oil distribution assembly is arranged between the second reservoir and the first reservoir, so that oil flows from the second pump to the oil distribution assembly, and after the oil lubricates the gear reduction assembly, flows to the first reservoir.

Claims

1. An electric vehicle transmission for a vehicle, comprising: a housing defining a housing interior; an electric motor disposed inside the housing, wherein the electric motor comprises a rotor and a stator; an input shaft disposed within the housing interior and extending along a shaft axis, wherein the input shaft is rotatably coupled to the rotor of the electric motor; a gear reduction assembly disposed within the housing interior, wherein the gear reduction assembly is rotatably coupled to the input shaft for transmitting rotational torque to wheels of the vehicle; wherein the housing defines a first reservoir for containing oil and a second reservoir for containing oil separated from the first reservoir; and Wherein, the second reservoir and the first reservoir are configured such that oil lubricates the gear reduction assembly when flowing from the second reservoir into the first reservoir.

2. The electric vehicle transmission according to claim 1, wherein: The second reservoir and the first reservoir are configured to passively control oil flow between the second reservoir and the first reservoir. 3 . The electric vehicle transmission according to claim 1 , further comprising a valve disposed between the second reservoir and the first reservoir to actively control oil flow between the second reservoir and the first reservoir.

4. An electric vehicle transmission according to any one of the preceding claims, wherein: The gear reduction assembly is further defined as a planetary gear set.

5. The electric vehicle transmission according to claim 4, wherein: The planetary gear set includes a plurality of pinion gears disposed about an axis of the shaft.

6. The electric vehicle transmission according to claim 5, wherein: The plurality of pinions are further defined as three pinions.

7. The electric vehicle transmission according to claim 6, wherein: The three pinions are radially separated from each other by 120 degrees about the axis of the shaft.

8. An electric vehicle transmission according to any one of the preceding claims, further comprising a carrier coupled to the gear reduction assembly, wherein: The carrier is configured to scoop oil from the first reservoir to the second reservoir during rotation of the gear reduction assembly.

9. The electric vehicle transmission according to claim 8, wherein: The carrier has a circular configuration.

10. The electric vehicle transmission according to any one of claims 8 and 9, wherein: The carrier has a first carrier surface facing in a first direction relative to the axis of the shaft and a second carrier surface facing in a second direction opposite to the first direction relative to the axis of the shaft, wherein the first carrier surface and the second carrier surface have a flat configuration.

11. The electric vehicle transmission according to any one of claims 8 and 9, wherein: The carrier has a first carrier surface and a second carrier surface, the first carrier surface facing in a first direction relative to the axis of the shaft, the second carrier surface facing in a second direction opposite to the first direction relative to the axis of the shaft, wherein the first carrier surface and the second carrier surface have protrusions and / or recesses.

12. The electric vehicle transmission according to any one of claims 8 and 9, wherein: The carrier has a first carrier surface facing in a first direction relative to the axis of the shaft and a second carrier surface facing in a second direction opposite to the first direction relative to the axis of the shaft, wherein at least one of the first carrier surface and the second carrier surface has protrusions and / or recesses for assisting in scooping oil from the first reservoir to the second reservoir during rotation of the carrier.

13. An electric vehicle transmission according to any one of the preceding claims, wherein: The housing includes a housing protrusion extending into the second reservoir for further defining the second reservoir.

14. An electric vehicle transmission according to any one of the preceding claims, wherein: The interior of the housing is divided into a motor side and a gear reduction side.

15. The electric vehicle transmission according to claim 14, wherein: The housing defines an upper overflow drain port in the second sump for allowing oil to flow between the motor side and the gear reduction side.

16. The electric vehicle transmission according to any one of claims 14 and 15, wherein: The housing defines a lower overflow drain orifice in the first sump for allowing oil to flow between the motor side and the gear reduction side.

17. The electric vehicle transmission according to any one of claims 14 to 16, further comprising a pump for circulating oil in the motor side inside the housing.

18. An electric vehicle transmission according to any one of claims 14 to 17, without a pump for circulating oil in the gear reduction side of the interior of the housing.

19. An electric vehicle transmission according to any one of the preceding claims, further comprising an oil distribution assembly disposed within the housing interior.

20. The electric vehicle transmission of claim 19, wherein: The oil distribution assembly is disposed between the second reservoir and the first reservoir such that oil flows from the second pump to the oil distribution assembly and flows to the first reservoir after the oil lubricates the gear reduction assembly.

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