阅读说明：本技术 具有差速器太阳齿轮断开式离合器的电动车桥 (Electric axle with differential sun gear disconnect clutch ) 是由 布莱恩·李 于 2020-03-26 设计创作，主要内容包括：一种电动车桥,该电动车桥构造成选择性地使电动马达能够为车辆的驱动轴提供动力。电动车桥包括差速器行星齿轮组,该差速器行星齿轮组构造成将驱动扭矩传递至驱动轴。差速器行星齿轮组具有构造成环绕驱动轴的太阳齿轮。离合器构造成选择性地将太阳齿轮以不可旋转的方式联接至驱动轴。离合器可以包括能够沿轴向方向移动的套筒。(An electric axle is configured to selectively enable an electric motor to power a drive shaft of a vehicle. The electric axle includes a differential planetary gear set configured to transfer drive torque to the drive shaft. The differential planetary gear set has a sun gear configured to encircle the drive shaft. The clutch is configured to selectively non-rotatably couple the sun gear to the drive shaft. The clutch may comprise a sleeve movable in an axial direction.)

1. An electric axle configured to selectively enable an electric motor to power a drive shaft of a vehicle, the electric axle comprising:

a differential planetary gear set configured to transmit drive torque to a drive shaft, the differential planetary gear set having a sun gear configured to encircle the drive shaft; and

a clutch configured to selectively non-rotatably couple the sun gear to the drive shaft.

2. The electric axle of claim 1, wherein the clutch includes a sleeve configured to move in an axial direction, wherein the sleeve selectively engages the sun gear when moved in the axial direction into a locked mode or an engaged mode.

3. The electric axle of claim 2, wherein the sun gear has an inner surface with a first set of radially extending teeth and the sleeve has an outer surface with a second set of radially extending teeth that mesh with the first set of radially extending teeth when the clutch is in the locked mode or the engaged mode.

4. The electric axle of claim 2, wherein the sleeve has an inner surface with radially extending teeth configured to mesh with corresponding teeth of the driveshaft.

5. The electric axle of claim 2, further comprising an actuator assembly including an actuator configured to move in the axial direction to urge the sleeve in the axial direction.

6. The electric axle of claim 5, wherein the actuator assembly includes a gear set configured to rotate an actuator nut, wherein rotation of the actuator nut urges the actuator in the axial direction.

7. The electric axle of claim 6, wherein the actuator nut has threads that mate with corresponding threads of the actuator.

8. The electric axle of claim 2, further comprising a spring wrapped around the sleeve and configured to return the sleeve to an unlocked mode or a disengaged mode.

9. An electric axle for a drive shaft, the electric axle comprising:

a housing;

a differential planetary gear set at least partially disposed within the housing, the differential planetary gear set including a sun gear rotatable within the housing, the sun gear having an inner surface defining teeth; and

a sleeve disposed radially inward of the sun gear, the sleeve having an outer surface defining a tooth portion that meshes with the tooth portion of the sun gear;

wherein the sleeve is axially movable between (i) an unlocked or disengaged position in which the sun gear is rotatable independently of the drive shaft, and (ii) a locked or engaged position in which the sleeve non-rotatably couples the sun gear with the drive shaft.

10. The electric axle of claim 9, wherein the sleeve has an inner surface defining teeth that mesh with the driveshaft, and further comprising an actuator assembly including an actuator configured to move the sleeve from the unlocked or disengaged position to the locked or engaged position.

Technical Field

The present disclosure relates to an electric axle ("trolley axle") equipped with a clutch for selectively enabling an electric motor to power wheels associated with the axle.

Background

Electric motors are increasingly being used as a source of driving power in vehicles to provide an alternative to conventional internal combustion engines that require fossil fuels. Considerable efforts have been made to improve the applicability of electric motors in all-electric or hybrid vehicles.

Electric axles, also referred to as electric axles or electric axles, for transmitting drive torque from an electric motor to an output and optionally via a reduction or acceleration drive transmission are known in the art. For example, a planetary gear set may be provided for transmitting torque from an electric motor to one or more axles while enabling the rotor of the electric motor to rotate at a different speed than the axles due to operation of the planetary gears.

Disclosure of Invention

According to one embodiment, an electric axle is configured to selectively enable an electric motor to power a drive shaft of a vehicle. The electric axle includes a differential planetary gear set configured to transfer drive torque to the drive shaft. The differential planetary gear set has a sun gear configured to encircle the drive shaft. The clutch is configured to selectively non-rotatably couple the sun gear to the drive shaft.

In another embodiment, an electric axle for a drive shaft includes a housing and a differential planetary gear set at least partially disposed within the housing. The differential planetary gear set includes a sun gear rotatable within a housing. The sun gear has an inner surface defining teeth. The sleeve is disposed radially inward of the sun gear. The sleeve has an outer surface defining teeth that mesh with the teeth of the sun gear. The sleeve is axially movable between (i) an unlocked or disengaged position in which the differential sun gear is rotatable independently of the drive shaft, and (ii) a locked or engaged position in which the sleeve non-rotatably couples the differential sun gear with the drive shaft.

In yet another embodiment, an electric axle includes: a planetary gear set including a sun gear; and a sleeve sized to fit around the drive shaft. The sleeve is configured to move in an axial direction in a gap between the sun gear and the drive shaft. The actuator assembly is configured to urge the sleeve in an axial direction to selectively non-rotatably lock the sleeve with both the sun gear and the drive shaft.

Drawings

FIG. 1 is a perspective view of an assembled electric axle assembly or electric vehicle axle according to one embodiment.

FIG. 2 is an enlarged perspective view of a portion of an electric axle according to one embodiment with the outer housing removed.

FIG. 3 is a cross-sectional view of the electric axle of FIG. 1.

FIG. 4 is an enlarged cross-sectional view of a portion of the electric axle of FIG. 3 with the clutch of the electric axle in an unlocked mode or a disengaged mode, according to one embodiment.

FIG. 5 is an enlarged cross-sectional view of a portion of the electric axle of FIG. 4 with a clutch of the electric axle in an engaged or locked mode, according to one embodiment.

FIG. 6 is an elevational cross-sectional view, taken along line 6-6 of FIG. 5, of a clutch actuator assembly for actuating a clutch of an electric axle, according to one embodiment.

FIG. 7 is a front cross-sectional view of a portion of the electric axle 10 in an engaged or locked mode along line 7-7 of FIG. 5 according to one embodiment.

Detailed Description

Embodiments of the present disclosure are described herein. However, it is to be understood that the disclosed embodiments are merely examples and that other embodiments may take different and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the embodiments. As one of ordinary skill in the art will appreciate, various features illustrated and described with reference to any one of the figures may be combined with features illustrated in one or more other figures to produce embodiments that are not explicitly illustrated or described. The combination of features illustrated provides a representative implementation for typical applications. However, various combinations and modifications of the features consistent with the teachings of the present disclosure may be desired for particular applications or implementations.

Directional terminology used herein is made with reference to the views and orientations shown in the exemplary drawings. The central axis is shown in the drawings and described below. Terms such as "outer" and "inner" are relative to the central axis. For example, "outer" surfaces mean that these surfaces face away from the central axis, or are external to another "inner" surface. Terms such as "radial," "diameter," "circumferential," and the like are also relative to the central axis. The terms "front", "rear", "upper" and "lower" designate directions in the drawings to which reference is made.

In hybrid electric vehicles, electric-only vehicles, and the like, the vehicle is driven at least in part by an electric motor. For example, the electric motor may be powered by a high voltage battery pack, and may be capable of performing regenerative braking to convert kinetic energy of the vehicle into electrical energy for storage in the battery.

Electric axles (also known as electric axles, electronic axles, etc.) may be located on the drive axle assembly of the vehicle. The electric axle may act as a differential, allowing the drive shaft to adopt different rotational speeds, for example, when the vehicle is turning. The electric axle may also transmit power from the motor to the drive shaft via an acceleration or deceleration transmission. Electric axles may eliminate the need for a drive shaft or propeller shaft, and each forward and aft axle may be independently powered or propelled.

According to the embodiments described herein, an electric axle is provided with a planetary differential with a sun gear and a disconnect clutch that selectively engages the sun gear. When the clutch is open or disengaged, the motor cannot power the drive shaft. In this mode, the wheels on the drive shafts may be passively rotated while the vehicle is running. When the clutch is closed or engaged, the sun gear is connected to the drive shaft, which enables torque from the electric motor to be transmitted to the drive shaft through the planetary differential. In certain embodiments described herein, the clutch includes a sleeve that functions as a dog clutch. The sleeve is axially movable to open or close the clutch. The sleeve may have a splined outer surface to always engage and rotate with the sun gear. The sleeve may also have an inner surface that engages the axle shaft when the sleeve is moved axially. The axle shaft may freely rotate relative to the sun gear when the sleeve is moved axially out of engagement. These concepts are merely examples of clutches provided at the sun gear of the differential, and further description of these concepts is described in the embodiments explained below.

The arrangement described below is just one embodiment of a disconnect clutch in an electric axle. The teachings of U.S. patent application No.16/376,125, which further discloses a disconnect clutch in an electric axle, are fully incorporated by reference herein. The teachings of the present disclosure and the teachings of U.S. patent application No.16/376,125 may be combined to form additional embodiments.

FIG. 1 illustrates an assembled electric axle assembly or electric axle 10. Fig. 2 illustrates an enlarged view of a portion of the electric axle assembly 10 with the outer housing removed for clarity. Fig. 3 shows a cross-sectional view of the electric axle 10, and fig. 4 shows an enlarged cross-sectional view of a portion of the electric axle 10 with the clutch in either a disengaged or an unlocked mode. Fig. 5 shows the electric axle 10 with the clutch in an engaged or locked mode. FIG. 6 illustrates the interaction of the clutch actuator assembly about the drive shaft. Fig. 7 shows an enlarged region of the powered axle 10 of fig. 5 in an engaged or locked mode, and fig. 8 shows a front cross-sectional view of a portion of the powered axle 10 in an engaged or locked mode. Reference is now made to the components illustrated in at least one of the figures.

The electric axle 10 is disposed about a central axis 11 and about a pair of drive shafts, such as a first drive shaft 12 and a second drive shaft 14. Each of the drive shafts 12, 14 is configured to rotate about the axis 11 to rotate a corresponding wheel (not shown). The drive shaft 12 may have a hollow core 13, which may reduce the overall mass of the shaft 12. An outer housing 16 or shell (removed in fig. 2) is provided and may include a first housing shell 18 and a second housing shell 20.

An electric motor 22 is accommodated in the second housing case 20. The electric motor 22 may be powered by a high voltage battery (not shown) such that the motor is configured to power the drive shafts 12, 14. The motor 22 may include a stator 24 and a rotor 26 having a corresponding rotor shaft 28 configured to rotate relative to the stator 24 about the axis 11 when energized. Rotor shaft 28 is rotatably coupled to second housing shell 20 such that rotor 26 may rotate within housing 16 while housing 16 remains stationary or grounded during operation. The rotor shaft 28 may also be coupled to the drive shaft 14.

The electric axle 10 includes a planetary gear set 30. In one embodiment, the planetary gear set 30 includes a sun gear 32 that is non-rotatably coupled (e.g., via splines) to the rotor shaft 28, for example. For example, the sun gear 32 is coupled to the planet gears 34 by meshing engagement. This allows the planet gears 34 to rotate about each of their own central axes while collectively rotating about the sun gear 32. The carrier 36 supports the planet gears 34. The planet gears 34 are also connected to the ring gear 38 in meshing engagement such that the planet gears 34 can rotate within (and relative to) the ring gear 38.

The electric axle 10 also includes a differential including a differential planetary gear set 31 that provides a torque vectoring function. The differential planetary gear set includes a differential sun gear 33 that circumscribes shaft 12. The differential planetary gear set may also share a common carrier 36 with the planetary gear set 30, or the differential planetary gear set may have a carrier that is engaged with or otherwise configured to rotate with carrier 36. There may be a pair of opposing differential sun gears. For example, a first differential sun gear 33 may be disposed about axle 12, and a second differential sun gear 35 may be disposed about axle 14. The second differential sun gear 35 may be directly engaged (e.g., meshed, splined) with the shaft 14. On the other hand, the first differential sun gear 33 may be radially spaced or gapped from the shaft 12 to accommodate a sleeve 52 described below.

A clutch pack or clutch 50 is also provided for selectively non-rotatably securing one axle shaft (e.g., shaft 12) to the corresponding differential sun gear 33. In other words, the clutch 50 may be activated to non-rotatably engage the shaft 12 with the differential sun gear 33, and the clutch may be deactivated to decouple the shaft 12 from the differential sun gear 33 and allow free rotation between the shaft and the differential sun gear. This connection point allows torque to flow through the planetary differential when the clutch is engaged.

The clutch assembly 50 includes a sleeve 52, which is also referred to as a dog clutch sleeve or dog clutch member. The sleeve 52 has an outer surface facing away from the central axis 11 that directly engages (e.g., is in splined engagement) with an inner surface of the differential sun gear 33. When the sleeve 52 is engaged with the differential sun gear 33, the sleeve 52 may move axially (e.g., to the right in the orientation of fig. 2) to also engage the outer surface of the shaft 12. In other words, axle shaft 12 is splined to engage the inner surface of sleeve 52 as sleeve 52 is axially moved into engagement with shaft 12. When the sleeve 52 is moved axially out of engagement (e.g., to the left in the orientation of fig. 2), the axle shaft 12 may rotate freely within the inner diameter of the differential sun gear 33.

An actuator assembly 60 is also provided for moving the sleeve 52 into and out of engagement between the shaft 12 and the sun gear 32. At least a portion of the actuator assembly 60 may be mounted or otherwise coupled to the exterior of the housing 18. The actuator assembly 60 includes an electric motor 62 configured to rotate a gear set 64 when energized. The gear set 64 is in meshing engagement with an actuator nut 66. The actuator nut 66 is connected to the actuator 68 by a threaded engagement. For example, the actuator 68 is connected to the sleeve 52 in face-to-face engagement. Thus, when motor 62 rotates gear set 64, gear set 64 rotates actuator nut 66 along the threads of actuator 68, thereby axially pushing actuator 68.

Referring to fig. 3 and 4, the clutch assembly 50 is shown in a disengaged state. The sleeve 52 is engaged with the sun gear 32 via a mesh or spline connection, but the sleeve 52 is not engaged with the shaft 12 so that the shaft 12 and the sleeve 52 can rotate independently of each other.

The engagement of the clutch assembly 50 is shown in fig. 5 and 7. Activation of the actuator assembly 60 via energization of the motor 62 (as described above) causes axial movement of the sleeve 52 as represented by arrow 51. When in the engaged or locked mode, the inner surface of the sleeve 52 is splined or otherwise engaged with the shaft 12 and the outer surface of the sleeve 52 is splined or otherwise engaged with the differential sun gear 33. This non-rotatably fixes the shaft 12 with the differential sun gear 33, allowing torque to be transferred through the differential planetary gear set and into the shaft 12 (or allowing torque to be transferred through the shaft and into the differential planetary gear set). As shown in fig. 7, the differential planet gears 70 mesh with and rotate about the differential sun gear 33.

As shown in fig. 5 and 7, the shaft 12 may be provided with spline features 72 only at an end region 74 of the shaft 12. The spline feature 72 extends outwardly from an end region of the shaft to define a larger outer diameter than the remainder of the shaft 12. These spline features 72 may include radially extending teeth sized and configured to mesh with the inner surface of the sleeve 52 when the sleeve 52 is actuated in the engaged or locked mode. Likewise, the differential sun gear 33 has spline features 76 that may include radially extending teeth configured to mesh with the outer surface of the sleeve 52 when the sleeve is actuated in the engaged or locked mode. The spline feature 76 of the differential sun gear 33 may continue to engage the outer surface of the sleeve 52 even when the sleeve is in the disengaged or unlocked mode (see, e.g., fig. 4).

A spring 78 may be disposed about the sleeve 52. When the actuator assembly no longer forces the sleeve 52 in the locked or engaged mode, the spring 78 may be biased to return the sleeve 52 to the unlocked or disengaged mode. In one embodiment, the spring 78 is located in the axial gap between the sleeve 52 and the differential sun gear 33. When the sleeve 52 is moved axially into the locked or engaged mode, the spring 78 compresses forcing the spring in the compressed state to bias the sleeve 52 back into the unlocked or disengaged mode of the sleeve. The sleeve 52 may be provided with a radially extending flange 80 at one end to axially accommodate the spring between the sleeve 52 and the differential sun gear 33.

While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the disclosure. As previously described, features of the various embodiments may be combined to form further embodiments of the invention, which may not be explicitly described or illustrated. While various embodiments may be described as providing advantages or being preferred over other embodiments or over prior art embodiments with respect to one or more desired characteristics, those skilled in the art will recognize that one or more features or characteristics may be compromised to achieve desired overall system attributes, which depend on the particular application and embodiment. These attributes may include, but are not limited to, cost, strength, durability, life cycle cost, market demand, appearance, packaging, size, suitability, weight, manufacturability, ease of assembly, and the like. Thus, any embodiment described as being somewhat less desirable in one or more characteristics than other embodiments or prior art implementations may not depart from the scope of the present disclosure and may be desirable for particular applications.

Description of the reference numerals

10 electric axle 11 center axis 12 first drive shaft 13 hollow core 14 second drive shaft 16 outer housing 18 first housing shell 20 second housing shell 22 electric motor 24 stator 26 rotor 28 planetary shaft 30 planetary gear set 31 differential planetary gear set 32 sun gear 33 differential sun gear 34 planetary gear 35 second differential sun gear 36 carrier 38 ring gear 50 clutch assembly 51 arrow 52 sleeve 60 actuator assembly 62 electric motor 64 gear set 66 actuator nut 68 actuator 70 differential planetary gear 72 spline feature 74 end region 76 spline feature 78 spring 80 flange.