Differential with disconnecting device

Abstract

The invention provides a differential with a disconnect device. A differential includes a disconnect feature. In the disengaged state, the drive gear is disengaged from the differential carrier. Thus, a portion of the powertrain that will provide propulsion through the differential may be stationary, and parasitic drag is reduced. The differential transitions to an engaged state by providing an electrical current in a solenoid coil fixed to a housing. A solenoid piston acts through a thrust bearing to slide a sleeve, thereby coupling the carrier to the drive gear.

Description

Technical Field

[0001] The present invention relates to an automobile axle assembly and more particularly to a differential that can be disconnected from a driving source. Background Art

[0002] Hybrid vehicles include multiple propulsion sources, such as an internal combustion engine and an electric motor. When one of these sources is not in use, it is beneficial if it can be stopped to reduce parasitic drag. A differential is typically used to distribute mechanical power from one or both propulsion sources to the left and right wheels while allowing a slight speed difference. Summary of the invention

[0003] A vehicle differential includes a drive gear, a gear carrier, a gear arrangement, and a sleeve. The drive gear is supported for rotation relative to a housing. The drive gear may be directly supported for rotation relative to the housing by two ball bearing assemblies. The gear carrier is directly supported for rotation relative to the drive gear by two sets of needle bearings. Each set of needle bearings contacts the drive gear and the gear carrier. The gear arrangement is configured to transmit torque from the gear carrier to a left stub shaft and a right stub shaft and constrain the gear carrier to rotate at a speed between the speed of the left stub shaft and the speed of the right stub shaft. The left stub shaft and the right stub shaft may be directly supported by the gear carrier. The gear arrangement may include a beveled left side gear and a beveled right side gear and a plurality of beveled planetary gears. The beveled left side gear is fixed to the left stub shaft. The beveled right side gear is fixed to the right stub shaft. The plurality of beveled planetary gears each mesh with the left side gear and the right side gear and are supported for rotation relative to the gear carrier. The distance from the rotational axis of the gear carrier to the needle bearing in the two sets of needle bearings can be less than the radius of the left gear. The sleeve is slidingly connected to the gear carrier and is configured to selectively couple the drive gear to the gear carrier. The solenoid coil can be fixed to the housing. The solenoid piston can be configured to slide axially in response to the current in the solenoid coil. A thrust bearing can be between the solenoid piston and the sleeve to push the sleeve into an engagement position with the drive gear. A compression spring can act between the gear carrier and the sleeve to push the sleeve away from the engagement position.

[0004] The vehicle differential includes a drive gear, a gear carrier, a gear arrangement, a sleeve, a solenoid coil, a solenoid piston, and a thrust bearing. The drive gear is supported to rotate relative to a housing. The drive gear may be directly supported by two ball bearing assemblies to rotate relative to the housing. The gear carrier is supported by two sets of needle bearings to rotate relative to the drive gear. Each set of needle bearings contacts the drive gear and the gear carrier. The gear arrangement is configured to transmit torque from the gear carrier to a left stub shaft and a right stub shaft and constrain the gear carrier to rotate at a speed between the speed of the left stub shaft and the speed of the right stub shaft. The left stub shaft and the right stub shaft may be directly supported by the gear carrier. The gear arrangement may include a beveled left side gear and a beveled right side gear and a plurality of beveled planetary gears. The beveled left side gear may be fixed to the left stub shaft. The beveled right side gear may be fixed to the right stub shaft. The plurality of beveled planetary gears may each mesh with the left side gear and the right side gear and be supported to rotate relative to the gear carrier. The distance from the rotational axis of the gear carrier to the needle bearing in the two sets of needle bearings can be less than the radius of the left gear. The sleeve is slidably connected to the gear carrier and is configured to selectively couple the drive gear to the gear carrier. The solenoid coil is fixed to the housing. The solenoid piston is configured to slide axially in response to the current in the solenoid coil. The thrust bearing pushes the sleeve to an engagement position with the drive gear in response to the axial movement of the solenoid piston. A compression spring can act between the gear carrier and the sleeve to push the sleeve away from the engagement position.

[0005] The vehicle differential includes a drive gear, a gear carrier, a beveled left side gear and a beveled right side gear, a plurality of beveled planetary gears and a sleeve. The drive gear is supported to rotate relative to a housing. The drive gear may be directly supported by two ball bearing assemblies to rotate relative to the housing. The gear carrier is supported by two sets of needle bearings to rotate relative to the drive gear. Each set of needle bearings contacts the drive gear and the gear carrier. The beveled left side gear is fixed to a left stub shaft. The beveled right side gear is fixed to a right stub shaft. The left stub shaft and the right stub shaft may be directly supported by the gear carrier. The plurality of beveled planetary gears mesh with the left side gear and the right side gear and are supported to rotate relative to the gear carrier. The sleeve is slidably connected to the gear carrier and is configured to selectively couple the drive gear to the gear carrier. The distance from the rotation axis of the gear carrier to the needle bearings in the two sets of needle bearings is less than the radius of the left side gear. A solenoid coil may be fixed to the housing. The solenoid piston can be configured to slide axially in response to the current in the solenoid coil. A thrust bearing between the solenoid piston and the sleeve can push the sleeve into an engagement position with the drive gear. A compression spring can act between the gear carrier and the sleeve to push the sleeve away from the engagement position. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 A block diagram of a hybrid vehicle powertrain is shown.

[0007] Figure 2 Shows the application Figure 1 A disconnectable differential for the hybrid powertrain.

[0008] Figure 3A and Figure 3B They are shown respectively Figure 2 A connector for a disconnectable differential in an engaged and disengaged state. DETAILED DESCRIPTION

[0009] Detailed embodiments of the present invention are disclosed herein; however, it should be understood that the disclosed embodiments are merely examples of the present invention that may be embodied in various forms and alternative forms. The drawings are not necessarily drawn to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, the specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching those skilled in the art to employ the present invention in various ways.

[0010] Figure 1A vehicle drivetrain configuration of a hybrid vehicle 10 is shown. Power is provided by an internal combustion engine 12 and by an electric motor 14. At a given time, power may be provided by the engine 12, by the motor 14, or by a combination of the two. The engine 12 drives the front wheels 16 and 18 via a transaxle 20. The electric motor 14 drives the rear wheels 22 and 24 via a rear differential 26. The transaxle 20 includes a variable ratio gearbox and a differential that distributes power between the left and right wheels while allowing a certain speed difference between the left and right wheels. During the time when only one of the two power sources is providing power, it is beneficial to disconnect the power source from the wheels to reduce the parasitic drag associated with spinning the power source quickly.

[0011] Figure 2 26 is a cross section of a differential 26 with a disconnect feature. Although this is a rear differential associated with an electric motor, a differential as part of a transaxle 20 can be similarly constructed. In addition, the differential can be used in other drivetrain configurations, such as a battery electric vehicle (BEV) that utilizes an electric motor to propel both the front and rear axles. The housing 30 is rotationally fixed to the vehicle structure. The housing can be in multiple parts, such as 30A and 30B. The drive gear 32 is supported to rotate relative to the housing 30 and is propelled by a power source. The drive gear 32 can be formed by several pieces attached to each other. In this example, the left and right portions 32A and 32B of the drive gear are attached to each other and to the gear element 32C. The left portion 32A is directly supported by the housing via ball bearings 34. The right portion 32B is directly supported by the housing via ball bearings 36. In the illustrated embodiment, the gear element 34C is a parallel axis helical gear. In other embodiments, other types of gear arrangements, such as hypoid gear arrangements, can be utilized.

[0012] Direct support means that there are no intermediate components between the components other than the bearing itself. For this purpose, the bearing races and the rolling elements of the bearing are considered to be part of the bearing. On the other hand, indirect support describes an arrangement in which intermediate components can have a different rotational speed than the supported and supporting elements.

[0013] The differential carrier 38 is directly supported by the drive gear 32 via needle bearings 40 and 42. A left stub shaft 44 and a right stub shaft 46 are directly supported by the differential carrier. The relative rotational speeds of the stub shafts and the carrier tend to be small, so bushings may be sufficient. The differential gearing distributes torque from the carrier to the left and right stub shafts while allowing for slight speed differences. The stub shafts are coupled to the respective wheels via half shafts. Several different types of differential gearing are known. In the illustrated embodiment, a beveled left side gear 48 is fixed to the left stub shaft 44, and a beveled right side gear 50 is fixed to the right stub shaft 46. A set of beveled planetary gears 52 are supported for rotation relative to the differential carrier 38. Each planetary gear meshes with both the left side gear and the right side gear.

[0014] Connector 54 selectively couples the differential gear carrier 38 to the drive gear 32. The structure and function of the connector will be described in more detail below. When the power source is used, the connector 54 is set in an engaged position to couple the drive gear to the gear carrier, thereby establishing a power flow path from the drive gear to the short shaft. Two components are considered to be connected when the speeds are constrained to be equal and rotational power can be transmitted between the components. When the power source is not used, the connector can be set in a disengaged position in which the drive gear and the differential gear carrier can rotate at different speeds. More specifically, the gear carrier will rotate at the average speed of the two wheels, while the drive gear can be stationary.

[0015] It is advantageous to support the rotating shaft using bearings located at a relatively small distance from the center of rotation. Figure 2 The configuration allows the use of bearings 34, 36, 40 and 42 that are relatively close to the center of rotation. More specifically, bearings 40 and 42 are located closer to the axis of rotation than the radius of side gears 48 and 50.

[0016] Figure 3A and Figure 3B Connector 54 is shown in greater detail. Figure 3A The connector is shown in an engaged position in which the gear carrier 38 is coupled to the drive gear 32 . Figure 3B The connector is shown in a disengaged position wherein the gear carrier 38 and the drive gear 32 are free to have different speeds with a small amount of drag torque between the two components. The connector 54 includes a sleeve 60 slidingly connected to the gear carrier 38. Specifically, the gear carrier 38 includes external splines 62 which mesh with internal splines 64 of the sleeve 60 such that the sleeve 60 rotates with the gear carrier 38 but can move axially. A solenoid coil 66 is fixed to the housing. The current in the solenoid coil forces the solenoid piston 68 toward the left. The solenoid piston 68, acting through a thrust bearing 70, pushes the sleeve 60 to the left. Figure 3AIn this engaged position, the end splines 72 of the sleeve 60 engage the end splines 74 of the drive gear 32, thereby coupling the drive gear to the gear carrier 38. When the current in the solenoid coil 66 is removed, the return spring 76 pushes the sleeve 60 to the right. Figure 3B In the disengaged position, the end splines 72 are not engaged with the end splines 74. Therefore, the speed of the drive gear 32 may be different from the speed of the gear carrier 38.

[0017] Although exemplary embodiments are described above, these embodiments are not intended to describe all possible forms of the present invention. Rather, the words used in the specification are descriptive rather than restrictive terms, and it should be understood that various changes can be made without departing from the spirit and scope of the present invention. In addition, the features of the various embodiments of implementation can be combined to form other embodiments of the present invention.

[0018] According to the present invention, a vehicle differential is provided, which has: a drive gear, which is supported to rotate relative to a housing; a gear carrier, which is directly supported by two sets of needle bearings to rotate relative to the drive gear, each set of needle bearings contacts the drive gear and the gear carrier; a gear device, which is configured to transmit torque from the gear carrier to a left stub shaft and a right stub shaft, and constrain the gear carrier to rotate at a speed between the speed of the left stub shaft and the speed of the right stub shaft; and a sleeve, which is slidably connected to the gear carrier and is configured to selectively connect the drive gear to the gear carrier.

[0019] According to an embodiment, the drive gear is directly supported for rotation relative to the housing by two ball bearing assemblies.

[0020] According to an embodiment, the gear device includes: a left-side gear with a bevel, which is fixed to the left short shaft; a right-side gear with a bevel, which is fixed to the right short shaft; and a plurality of planetary gears with bevels, each of which is meshed with the left gear and the right gear and is supported to rotate relative to the gear carrier.

[0021] According to an embodiment, a distance from the rotation axis of the gear carrier to a needle bearing in the two sets of needle bearings is smaller than a radius of the left gear.

[0022] According to an embodiment, the left stub shaft and the right stub shaft are directly supported by the gear carrier.

[0023] According to an embodiment, the present invention is also characterized by: a solenoid coil, which is fixed to the housing; a solenoid piston, which is configured to slide axially in response to the current in the solenoid coil; and a thrust bearing, which is between the solenoid piston and the sleeve to push the sleeve into an engagement position with the drive gear.

[0024] According to an embodiment, the invention is also characterized by a compression spring acting between the carrier and the sleeve to urge the sleeve away from the engaged position.

[0025] According to the present invention, a vehicle differential is provided, which has: a drive gear, which is supported to rotate relative to a housing; a gear carrier, which is supported by two sets of needle bearings to rotate relative to the drive gear, each set of needle bearings contacts the drive gear and the gear carrier; a gear device, which is configured to transmit torque from the gear carrier to a left stub shaft and a right stub shaft, and constrain the gear carrier to rotate at a speed between the speed of the left stub shaft and the speed of the right stub shaft; a solenoid coil, which is fixed to the housing; a solenoid piston, which is configured to slide axially in response to an electric current in the solenoid coil; and a thrust bearing, which is between the solenoid piston and the sleeve to push the sleeve into an engagement position with the drive gear.

[0026] According to an embodiment, the invention is also characterized by a compression spring acting between the carrier and the sleeve to urge the sleeve away from the engaged position.

[0027] According to an embodiment, the drive gear is directly supported for rotation relative to the housing by two ball bearing assemblies.

[0028] According to an embodiment, the gear device includes: a left-side gear with a bevel, which is fixed to the left short shaft; a right-side gear with a bevel, which is fixed to the right short shaft; and a plurality of planetary gears with bevels, each of which is meshed with the left gear and the right gear and is supported to rotate relative to the gear carrier.

[0029] According to an embodiment, a distance from the rotation axis of the gear carrier to a needle bearing in the two sets of needle bearings is smaller than a radius of the left gear.

[0030] According to an embodiment, the left stub shaft and the right stub shaft are directly supported by the gear carrier.

[0031] According to the present invention, a vehicle differential is provided, which comprises: a drive gear, which is supported to rotate relative to a housing; a gear carrier, which is supported by two sets of needle bearings to rotate relative to the drive gear, each set of needle bearings contacts the drive gear and the gear carrier; a beveled left side gear, which is fixed to a left stub shaft; a beveled right side gear, which is fixed to a right stub shaft; a plurality of beveled planetary gears, which are each meshed with the left side gear and the right side gear and are supported to rotate relative to the gear carrier; and a sleeve, which is slidably connected to the gear carrier and is configured to selectively connect the drive gear to the gear carrier, wherein the distance from the rotation axis of the gear carrier to a needle bearing in the two sets of needle bearings is less than the radius of the left side gear.

[0032] According to an embodiment, the drive gear is directly supported for rotation relative to the housing by two ball bearing assemblies.

[0033] According to an embodiment, the left stub shaft and the right stub shaft are directly supported by the gear carrier.

[0034] According to an embodiment, the present invention is also characterized by: a solenoid coil, which is fixed to the housing; a solenoid piston, which is configured to slide axially in response to the current in the solenoid coil; and a thrust bearing, which is between the solenoid piston and the sleeve to push the sleeve into an engagement position with the drive gear.

[0035] According to an embodiment, the invention is also characterized by a compression spring acting between the carrier and the sleeve to urge the sleeve away from the engaged position.

Claims

1. A vehicle differential, comprising: a drive gear supported for rotation relative to the housing; a gear carrier, the gear carrier being directly supported for rotation relative to the drive gear by two sets of needle bearings, each set of needle bearings contacting the drive gear and the gear carrier; a gear arrangement configured to transmit torque from the carrier to the left and right stub shafts and to constrain the carrier to rotate at a speed between a speed of the left stub shaft and a speed of the right stub shaft; as well as A sleeve is slidingly connected to the carrier and is configured to selectively couple the drive gear to the carrier.

2. The vehicle differential of claim 1, wherein the drive gear is directly supported by two ball bearing assemblies for rotation relative to the housing.

3. The vehicle differential of claim 1, wherein the gear arrangement comprises: a left side gear with a bevel, the left side gear with a bevel fixed to the left stub shaft; a right gear with a bevel surface, the right gear with a bevel surface being fixed to the right stub shaft; as well as A plurality of planetary gears with bevel surfaces are respectively meshed with the left side gear and the right side gear and are supported to rotate relative to the carrier.

4. The vehicle differential of claim 3, wherein a distance from the rotation axis of the carrier to a needle bearing in the two sets of needle bearings is smaller than a radius of the left side gear.

5. The vehicle differential as claimed in claim 1, wherein the left stub shaft and the right stub shaft are directly supported by the gear carrier.

6. The vehicle differential of claim 1, further comprising: a solenoid coil fixed to the housing; a solenoid piston configured to slide axially in response to an electric current in the solenoid coil; as well as A thrust bearing is between the solenoid piston and the sleeve to push the sleeve into engagement with the drive gear.

7. A vehicle differential, comprising: a drive gear supported for rotation relative to the housing; a gear carrier supported by two sets of needle bearings for rotation relative to the drive gear, each set of needle bearings contacting the drive gear and the gear carrier; a gear arrangement configured to transmit torque from the carrier to the left and right stub shafts and to constrain the carrier to rotate at a speed between a speed of the left stub shaft and a speed of the right stub shaft; a sleeve slidably connected to the gear carrier and configured to selectively couple the drive gear to the gear carrier; a solenoid coil fixed to the housing; a solenoid piston configured to slide axially in response to an electric current in the solenoid coil; as well as A thrust bearing is between the solenoid piston and the sleeve to push the sleeve into engagement with the drive gear.

8. The vehicle differential of claim 7 further comprising a compression spring acting between the carrier and the sleeve to urge the sleeve away from the engaged position.

9. The vehicle differential of claim 7, wherein the drive gear is directly supported by two ball bearing assemblies for rotation relative to the housing.

10. The vehicle differential of claim 7, wherein the gear arrangement comprises: a left side gear with a bevel, the left side gear with a bevel fixed to the left stub shaft; a right gear with a bevel surface, the right gear with a bevel surface being fixed to the right stub shaft; as well as a plurality of beveled planetary gears each meshing with the left side gear and the right side gear and supported for rotation relative to the gear carrier; The distance from the rotation axis of the gear carrier to the needle bearings in the two sets of needle bearings is smaller than the radius of the left gear.

11. The vehicle differential of claim 7, wherein the left stub shaft and the right stub shaft are directly supported by the carrier.

12. A vehicle differential comprising: a drive gear supported for rotation relative to the housing; a gear carrier supported by two sets of needle bearings for rotation relative to the drive gear, each set of needle bearings contacting the drive gear and the gear carrier; a left side gear with a bevel surface, wherein the left side gear with a bevel surface is fixed to the left stub shaft; a right side gear with a bevel surface, wherein the right side gear with a bevel surface is fixed to the right stub shaft; a plurality of beveled planetary gears each meshing with the left side gear and the right side gear and supported for rotation relative to the gear carrier; as well as a sleeve slidably connected to the gear carrier and configured to selectively couple the drive gear to the gear carrier; The distance from the rotation axis of the gear carrier to the needle bearings in the two sets of needle bearings is smaller than the radius of the left gear.

13. The vehicle differential of claim 12, wherein the drive gear is directly supported for rotation relative to the housing by two ball bearing assemblies.

14. The vehicle differential of claim 12, wherein the left stub shaft and the right stub shaft are directly supported by the carrier.

15. The vehicle differential of claim 12, further comprising: a solenoid coil fixed to the housing; a solenoid piston configured to slide axially in response to an electric current in the solenoid coil; a thrust bearing between the solenoid piston and the sleeve to push the sleeve into engagement with the drive gear; as well as A compression spring acts between the carrier and the sleeve to urge the sleeve away from the engaged position.

Images