Drive unit with differential and bearing support assembly

Abstract

A drive unit for a vehicle includes a differential having a plurality of differential gears and a housing, an input gear mounted on the housing for rotation with the housing, an input shaft driven for rotation about a first axis, a drive gear carried by the input shaft for rotation with the input shaft, the drive gear meshing with the input gear such that the input gear rotates when the input shaft rotates, and a support bearing assembly. The support bearing assembly includes a first bearing component coupled to the input shaft and having a first bearing surface, and a second bearing component having a second bearing surface arranged to be selectively engaged by the first bearing component.

Description

[0001] Citation of relevant applications This application claims a benefit from U.S. Provisional Application No. 63 / 759,739, filed on February 18, 2025, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0002] This disclosure generally relates to an automotive drive unit that includes a differential. Background Technology

[0003] Torque within a vehicle's drivetrain tends to flex certain components, such as shafts. Shaft bearings help maintain alignment between the shaft and gears, as well as the shaft joints. Some shafts extend into a housing and have gears at their ends and within the housing that mesh with another gear, such as the input gear of a differential. The shaft bearings are then spaced from the gear ends of the shaft, and as the shaft rotates in a direction associated with the vehicle's rearward or reverse movement, forces exist between the shaft gears and the input gear that tend to flex the shaft and disengage the gears. Flexural or bending forces on the input shaft can damage one or more components, such as the shaft bearings, and can damage one or more teeth or gears, or cause one or more teeth or gears to fail, due to reduced overlap / meshing of the gear teeth. Summary of the Invention

[0004] In at least some embodiments, a drive unit for a vehicle includes: a differential having a plurality of differential gears and a housing; an input gear mounted on the housing for rotation with the housing; an input shaft driven for rotation about a first axis; a drive gear carried by an input bearing for rotation with the input shaft, the drive gear meshing with the input gear such that the input gear rotates when the input shaft rotates; and a support bearing assembly. The support bearing assembly includes: a first bearing member coupled to the input shaft and having a first bearing surface; and a second bearing member having a second bearing surface arranged to selectively engage with the first bearing member.

[0005] In at least some embodiments, in the normal operating position of the input shaft, the clearance is provided between the first bearing surface and the second bearing surface.

[0006] In at least some embodiments, the second bearing surface is arranged to prevent the drive gear from moving away from the ring gear.

[0007] In at least some embodiments, the differential is received in a housing, a portion of the input shaft extends into the housing, and a second bearing component is carried by the housing. In at least some embodiments, the drive gear is carried at or near the free end of the input shaft, and a first bearing component is received axially relative to a first axis between the input shaft and the housing.

[0008] In at least some embodiments, the second bearing surface is part of an annular body. In at least some embodiments, the second bearing surface spans between 45 degrees and 270 degrees.

[0009] In at least some embodiments, when the first bearing surface engages with the second bearing surface, at least a portion of the first bearing component rotates relative to the input shaft.

[0010] In at least some embodiments, the second bearing component is arranged to be engaged by the first bearing component when a force on the drive gear causes the drive gear to move in a direction that reduces the engagement between the drive gear and the ring gear. In at least some embodiments, the second bearing surface is part of a ring body and spans between 45 degrees and 270 degrees.

[0011] In at least some embodiments, the differential is received in a housing, a portion of the input shaft extends into the housing, and a second bearing assembly is carried by the housing. The drive gear is carried at or near the free end of the input shaft. A first bearing assembly is received axially relative to a first axis between the input shaft and the housing, and the second bearing surface is not a complete ring. In at least some embodiments, the second bearing surface spans between 45 degrees and 270 degrees.

[0012] In at least some embodiments, a method of assembling a drive unit for a vehicle includes: providing a housing; mounting an input shaft into the housing, the input shaft having a drive gear that rotates with the input shaft and a first bearing component carried by the input shaft; mounting a second bearing component into the housing and mounting it relative to the first bearing component; and mounting a differential gear into the housing.

[0013] In at least some embodiments, the second bearing component is not a complete ring and is mounted in the housing in a position selected such that the first bearing component selectively engages with the second bearing component.

[0014] In at least some embodiments, in the mounting position, a gap is provided between the first bearing surface and the second bearing surface. In at least some embodiments, the second bearing surface is positioned such that, during operation of the drive unit, engagement of the first bearing component and the second bearing component prevents deflection of the input shaft in at least one direction. Attached Figure Description

[0015] The following detailed description of preferred embodiments and best modes will be illustrated with reference to the accompanying drawings, in which: Figure 1 This is a cross-sectional view of a portion of the drive unit, showing the differential, the ring gear on the differential housing, and the input shaft arranged to drive the ring gear; Figure 2 It is a schematic end view of the input shaft including the bearing assembly; Figure 3 This is a perspective view of a portion of the drive unit, with the drive unit housing removed; Figure 4 This is a side view of a portion of the drive unit; and Figure 5 This is a partial cross-sectional view showing the bearing assembly in the drive unit. Detailed Implementation

[0016] Refer to the references for more details. Figure 1 A vehicle drive unit 10 is shown, which may be mounted in a vehicle drivetrain, for example, between the side axles of the front or rear axle. Generally, the drive unit 10 includes a differential 11, which may have different designs and configurations depending on (among other possible influencing factors) the architecture of a large AWD vehicle drivetrain, upstream and downstream drivetrain components, packaging requirements, and torque output demands. In the embodiment presented in the figures, the drive unit 10 includes a housing 12 in which the differential is received.

[0017] The differential 11 includes a housing 13, a first pinion 14, a second pinion 16, a first side gear 18, and a second side gear 20; and in other embodiments, it may include more, fewer, and / or different components. For example, the differential 11 may have more than two pinions, and may have three or four or more pinions. The housing 13 is externally coupled to an annular input gear (referred to as an annular gear 22), and the annular gear 22 is coupled to a drive gear 24 of an input shaft 26, which is rotated by the vehicle powertrain (e.g., by an upstream output gear, such as the output gear of a transmission in a front axle layout or the output gear of a propeller shaft in an automotive drivetrain). When driven, the housing 13 rotates about axis (A), and a suitable bearing 28 may be disposed between the housing 13 and the drive unit housing 12.

[0018] In the assembly and use of the differential 11, the teeth of the first pinion 14 mesh with the teeth of the first side gear 18 and the second side gear 20, and the teeth of the second pinion 16 mesh with the teeth of the first side gear 18 and the second side gear 20. The first pinion 14 and the second pinion 16 include a passage through which a pinion shaft 30 extends. The pinion shaft 30 has a central axis (B) and is mounted in an opening 32 on opposite sides of the differential housing 13. The first side gear 18 has a set of internal splines 34 for connection to a first side shaft 36, the end of which is received in a first opening 38 of the housing 13, and the second side gear 20 has a set of internal splines 40 for connection to a second side shaft 42, the end of which is received in a generally oppositely facing second opening 44 in the housing 13. The side shafts 36 and 42 rotate about axis (A) during use.

[0019] The input shaft 26 extends into the housing 12 through a third opening 46 and carries the drive gear 24 at or near its free end 48. The input shaft 26 rotates about an axis of rotation (C), and suitable bearings may be disposed between the input shaft 26 and the housing 12, spaced apart from the drive gear 24. In at least some embodiments, a first bearing 50 (which may be referred to as a head bearing) is disposed near the drive gear 24. A second bearing 52 (which may be referred to as a tail bearing) is axially spaced from the head bearing 50 and further axially spaced from the drive gear 24 to provide two rotational support positions for the input shaft 26. The drive gear 24 and the ring gear 22 have meshing teeth such that when the input shaft 26 rotates, the ring gear 22 and the differential housing 13 rotate about an axis (A).

[0020] In at least some embodiments, the axis of rotation (A) of the ring gear 22 and housing 13 is not parallel to the axis of rotation (C) of the input shaft 26 and drive gear 24, and may be perpendicular to this axis of rotation. In the example shown, the drive gear 24 and ring gear 22 are quasi-hypoid gears, but other gear types may be used as desired. The teeth of the ring gear 22 and drive gear 24 are arranged at an angle to the axes of rotation (A, C), and when the input shaft 26 rotates in a first direction (intended to cause forward movement of the vehicle), torque is transmitted from the input shaft 26 through the drive gear 24 and ring gear 22 to the differential housing 13, and from the differential housing 13 through differential gears 14, 16, 18 and 20 to the side shafts 36, 42.

[0021] When the input shaft 26 rotates in the opposite second direction (intended to cause the vehicle to move backward or in reverse), the torque flow path to the side shafts 36, 42 is the same. However, in this direction of rotation, there is a force between the drive gear 24 and the ring gear 22 that tends to disengage the gears. With the differential 11 and the ring gear 22 firmly supported in the housing 12, the force tends to elastically flex or deform the input shaft 26 in a direction that reduces the meshing overlap of the drive gear teeth and the ring gear teeth (e.g., disengaging the drive gear 24 from the ring gear 22). Under normal operating forces, a lower torque is required during vehicle reversing operation, and this force is borne by the drive unit components (e.g., bearings 50, 52). However, under the higher forces generated during the reversing operation of a vehicle with higher torque, the flexural or bending force on the input shaft 26 may damage or cause one or both bearings 50, 52 to fail, and due to the reduced overlap of gear teeth, may damage or cause one or more teeth or meshing gears 22, 24 to fail.

[0022] In at least some embodiments, a support bearing assembly 54 is provided to withstand higher forces on the input shaft 26 in a direction tending to separate the drive gear 24 from the ring gear 22. The support bearing assembly 54 includes a first bearing member 56 carried by the input shaft 26 and fixed to rotate with the input shaft 26 at its free end 48. The drive gear 24 is positioned between the head bearing 50 and the first bearing member 56. The first bearing member 56 has a circular periphery, is coaxial with the drive gear 24, may have a smaller diameter than the drive gear 24, may have a smaller diameter than the free end 48 of the input shaft 26, and extends axially outward beyond the end face 58 of the drive gear 24 (relative to the axis of rotation (C) of the input shaft).

[0023] The first bearing component 56 may be a rotary bearing having an inner ring fixed to the input shaft 26 and an outer ring rotatably coupled to the inner ring, and having a cylindrical outer surface defining a first bearing surface 60 of the first bearing component 56. As a non-limiting example, the first bearing component may be a non-rotating portion, such as a bushing or protrusion integral with the end of the input shaft. The first bearing component 56 may be formed of any desired material to provide a bearing surface that allows rotation relative to the second bearing component 62, as described later. In at least some embodiments, the first bearing component 56 may be formed of cast iron, hardened steel, or sintered metal (including, but not limited to, sintered bronze).

[0024] To limit the movement of the first bearing assembly 56 and the drive gear 24 away from the ring gear 22, the support bearing assembly 54 includes a second bearing assembly 62, which is arranged under at least some operating conditions to provide rotational support for the first bearing assembly 56. The second bearing assembly... Figure 3 and Figure 4 The diagram is illustrated by rectangles, and in Figure 1 , Figure 2 and Figure 5 It is shown in various non-restrictive forms.

[0025] The second bearing component 62 is fixed in place, for example, by means of a member fixed to the housing 12 or to the housing 12. The second bearing component 62 includes a second bearing surface 64, which is concave and complementary in shape to the first bearing surface 60 of the first bearing component 56. In at least some embodiments, the second bearing surface 64 is not annular, but rather a portion of an annular body. In at least some embodiments, the second bearing surface 64 may be half of an annular body (e.g., as shown in the image). Figure 5 (as shown in the general) to a quarter (e.g., as shown in the general) Figure 1 and Figure 2 (Generally shown) (e.g., extending circumferentially between 90 and 180 degrees), but the second bearing surface 64 may span a larger or smaller circumferential range. When the second bearing surface 64 of the second bearing component 62 is not a complete ring, it can be received within a smaller area of ​​the drive unit 10 without interfering with the differential housing 13 rotating within the housing 12 during use. Figure 5 In the example shown, the second bearing surface 64 is defined in a body or bracket 65 (e.g., secured to the housing 12 by one or more bolts 67) and may have sides 69 that engage support surfaces of the housing. These support surfaces may be arranged complementaryly to provide support to the second bearing component in use. The second bearing surface 64 may be a relatively smooth, stationary surface (e.g., non-rotating) or may include one or more rotating elements (e.g., balls, needles, or other rollers rotatable relative to the body / bracket 65). The second bearing component 62 may be formed of the material described herein for the first bearing component and, in other respects, supports the first bearing component and allows rotation of the first bearing component relative to the second bearing component.

[0026] When the second bearing surface 64 of the second bearing component 62 engages with the first bearing surface 60 of the first bearing component 56, radial movement of the first bearing component 56 (relative to the input shaft 26 and the axis of rotation of the first bearing component 56) is prevented. In at least some embodiments, such as Figure 2 and Figure 5As shown, in the normal arrangement of the drive unit 10, a clearance 66 is provided between the first bearing component 56 and the second bearing component 62, and the first bearing component 56 engages the second bearing component 62 only when a force on the input shaft 26 causes the first bearing component 56 to move toward the second bearing component 62. In the example shown, this occurs during operation requiring higher torque when the vehicle is reversing, as described earlier. Without this force on the input shaft 26, the first bearing component 56 does not engage the second bearing component 62. The clearance 66 between the first bearing surface 60 and the second bearing surface 64 can be made very small, thereby limiting radial offset or deflection of the input shaft 26 to prevent overload and damage to portions of the drive gear 24, ring gear 22, or other bearings (e.g., bearings 50, 52) associated with the input shaft 26.

[0027] In at least some embodiments, the second bearing component 62 does not have a fully annular bearing surface 64. This, for example, reduces the size of the bearing component 62, which is desirable in automotive applications where space and weight saving are priorities. Furthermore, in at least some embodiments, at least a portion of the second bearing component 62 is axially received between the differential housing 13 and the drive gear 24 (relative to axis (A)). As will be explained later, the partially annular second bearing surface 64 facilitates the assembly of the second bearing component 62 into the housing.

[0028] Additionally, in at least some embodiments, the input shaft 26 is radially offset from the pinion shaft 30 relative to its axis (C). That is, the axis of rotation (B) of the pinion shaft 30 is offset from the axis of rotation (C) of the input shaft 26. In differentials having multiple pinion shafts, pinion shafts 30 oriented in the same general direction as the input shaft 26 can be considered in this respect. The differential housing 13, radially offset from the pinion shaft 30 and radially extending beyond the pinion, may taper or narrow near the side shafts 36, 42 (and bearing 28) toward the end 68 of the housing to provide space in which the second bearing component 62 can be disposed.

[0029] Alternatively, or to replace this deviation, such as Figure 4 As shown, the pinion shaft 30 may be tilted relative to an imaginary plane 70 (i.e., not parallel to the imaginary plane 70) (e.g., at an angle 71 of up to fifteen degrees in at least some embodiments), which includes / is parallel to both the rotational axes (A) of the side shafts 36, 42 and the rotational axis (B) of the pinion shaft 30. This angle of the pinion shaft 30 provides clearances or open spaces 72 of varying sizes between the drive gear 24 and the free end 48 of the input shaft 26, having a maximum open space 72 in one region 74 and a minimum open space 72 in another region 76. Figure 4As shown in the diagram, region 74, which has the largest open space, and the area near region 74 provide additional space for receiving the second bearing assembly 62. This avoids the need to make the ring gear 22 larger, or reduces the extent to which the ring gear 22 must be made larger or extend further from the differential housing 13 to accommodate the second bearing assembly 62.

[0030] In at least some embodiments, the drive unit can be assembled by first mounting its input shaft 26, on which a drive gear 24 is mounted, into the housing 12, wherein the input shaft 26 extends through associated bearings 50, 52. This is achieved by removing a cover defining a portion of the housing 12 to expose the interior of the housing 12. Next, as shown, a second bearing component 62 can be inserted and secured into the interior of the housing 12, wherein a second bearing surface 64 is located radially outside and axially aligned with a first bearing surface 60. Subsequently, a differential 11, on which a ring gear 22 is mounted, can be installed into the drive unit. The partially annular second bearing surface 64 facilitates assembly into the drive unit housing 12 and provides clearance with the ring gear 22 while still supporting the first bearing component 56 and the input shaft 26 to prevent displacement of the ring gear 22, as described herein.

[0031] It should be understood that the above description is intended to be exemplary and not limiting. Many other embodiments and applications beyond the examples provided will arise for those skilled in the art upon reading the above description. For example, various bearings or bushings or other relative rotational arrangements may be incorporated into and provided by the bearing support assembly 54 to allow at least partial rotation of the input shaft and the first bearing component relative to the second bearing component. The scope of the invention should not be determined by reference to the above description, but rather by reference to the appended claims, together with the full scope of equivalents conferred by those claims. Future developments in the technical fields discussed herein are anticipated and planned, and the disclosed components and methods will be incorporated into such future embodiments. In summary, it should be understood that the invention is capable of various modifications and variations, limited only by the following claims.

[0032] Unless expressly indicated otherwise herein, all terms used in the claims are intended to be given the broadest reasonable composition and the common meaning understood by one skilled in the art. In particular, the use of singular articles such as “a,” “the,” “the,” etc., should be understood to refer to one or more indicated elements, unless the claims expressly state a limitation to the contrary. In the foregoing description, various operating parameters and components have been described with respect to one or more exemplary embodiments. These specific parameters and components are listed by way of example only and are not intended to be restrictive.

[0033] The terms "an example," "an embodiment," "an implementation," "an implementation method," or "at least some implementation methods" used in the foregoing description refer to a specific feature, structure, or characteristic associated with that example that is included in at least one example or implementation method, which includes one or more (but not necessarily all) innovative features or components. The various examples, embodiments, or implementation methods mentioned herein do not necessarily refer to the same example, embodiment, or implementation method every time they appear.

Claims

1. A drive unit for a vehicle, comprising: A differential, the differential having multiple differential gears and a housing; An input gear, which is mounted on the housing for rotating with the housing; An input shaft, which is driven to rotate about a first axis; A drive gear, carried by the input bearing for rotation with the input shaft, meshes with the input gear such that the input gear rotates when the input shaft rotates; as well as A support bearing assembly includes a first bearing component and a second bearing component, the first bearing component being coupled to the input shaft and having a first bearing surface, and the second bearing component having a second bearing surface, which is arranged to selectively engage with the first bearing component.

2. The driving unit according to claim 1, wherein, In the normal operating position of the input shaft, the gap is located between the first bearing surface and the second bearing surface.

3. The driving unit according to claim 1, wherein, The second bearing surface is arranged to prevent the drive gear from moving away from the ring gear.

4. The drive unit of claim 1, further comprising a housing, the differential being received in the housing, and a portion of the input shaft extending into the housing, wherein, The second bearing component is supported by the housing.

5. The driving unit according to claim 4, wherein, The drive gear is carried at or near the free end of the input shaft, and the first bearing component is axially received between the input shaft and the housing relative to the first axis.

6. The driving unit according to claim 1, wherein, The second bearing surface is part of an annular structure.

7. The driving unit according to claim 6, wherein, The second bearing surface spans between 45 degrees and 270 degrees.

8. The driving unit according to claim 1, wherein, When the first bearing surface engages with the second bearing surface, the first bearing component does not rotate relative to the input shaft.

9. The driving unit according to claim 1, wherein, When the first bearing surface engages with the second bearing surface, at least a portion of the first bearing component rotates relative to the input shaft.

10. The driving unit according to claim 3, wherein, The second bearing component is arranged to be engaged by the first bearing component when a force on the drive gear causes the drive gear to move in a direction that reduces the engagement between the drive gear and the ring gear.

11. The drive unit according to claim 10, wherein, The second bearing surface is part of an annular body, and the second bearing surface spans between 45 degrees and 270 degrees.

12. The drive unit of claim 1, further comprising a housing, the differential being received in the housing, and a portion of the input shaft extending into the housing, wherein, The second bearing component is supported by the housing, the drive gear is supported at or near the free end of the input shaft, the first bearing component is axially received between the input shaft and the housing relative to the first axis, and the surface of the second bearing is not completely annular.

13. The drive unit according to claim 12, wherein, The second bearing surface spans between 45 degrees and 270 degrees.

14. A method of assembling a drive unit for a vehicle, comprising: Provide the shell; An input shaft is installed into the housing, the input shaft having a drive gear that rotates with the input shaft and a first bearing component carried by the input shaft; The second bearing component is installed into the housing and is mounted relative to the first bearing component; as well as Install the differential into the housing.

15. The method according to claim 14, wherein, The second bearing component is not a complete ring and is mounted in the housing in a position selected such that the first bearing component selectively engages the second bearing component.

16. The method of claim 14, wherein, In the installation position, the gap is located between the first bearing surface and the second bearing surface.

17. The method according to claim 16, wherein, The second bearing surface is positioned such that, during operation of the drive unit, engagement of the first bearing component with the second bearing component prevents the input shaft from deflecting in at least one direction.

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