阅读说明：本技术 具有带预载摩擦离合器的限滑差速器组件的动力传输部件 (Power transmitting component having limited slip differential assembly with preloaded friction clutch ) 是由 肖恩·S·普罗克特 道格拉斯·J·舍梅利 于 2020-04-20 设计创作，主要内容包括：一种具有差速器组件的传动系统动力传输部件,所述差速器组件具有差速器输入端、由所述差速器输入端驱动的第一差速器输出端和第二差速器输出端、第一摩擦离合器、第一偏压弹簧和第二摩擦离合器。所述第一摩擦离合器具有不可旋转地但可轴向滑动地联接至所述差速器输入端的摩擦片。所述第一偏压弹簧促使所述第一摩擦离合器进入接合状况,其中所述第一摩擦离合器的所述摩擦片与所述第一差速器输出端摩擦地接合。所述第二摩擦离合器具有可轴向滑动地但不可旋转地联接至所述差速器输入端的多个第一离合器片,和与所述第一离合器片交错且可轴向滑动地但不可旋转地联接至所述第一差速器输出端的多个第二离合器片。(A driveline power transmitting component having a differential assembly with a differential input, first and second differential outputs driven by the differential input, a first friction clutch, a first biasing spring, and a second friction clutch. The first friction clutch has friction plates non-rotatably but axially slidably coupled to the differential input. The first biasing spring urges the first friction clutch into an engaged condition, wherein the friction plates of the first friction clutch are frictionally engaged with the first differential output. The second friction clutch has a plurality of first clutch plates axially slidably but non-rotatably coupled to the differential input and a plurality of second clutch plates interleaved with the first clutch plates and axially slidably but non-rotatably coupled to the first differential output.)

1. A driveline power transmitting component comprising:

a differential assembly having a differential input, first and second differential outputs driven by the differential input, a first friction clutch having at least one friction plate non-rotatably but axially slidably coupled to the differential input, a first bias spring urging the first friction clutch into an engaged condition in which the at least one friction plate of the first friction clutch is frictionally engaged with the first differential output so as to resist relative rotation between the first differential output and the differential input, and a second friction clutch having a plurality of first clutch plates axially slidably but non-rotatably coupled to the differential input, and a plurality of first clutch plates interleaved with the first clutch plates and axially slidably but non-rotatably coupled to the first differential output A plurality of second clutch plates.

2. The driveline power transmitting component of claim 1, wherein the differential input is a differential case housing the first differential output and the second differential output.

3. The driveline power transmitting component of claim 2, wherein the differential assembly further comprises a differential gear set having a first side gear rotatably coupled to the first differential output and a second side gear rotatably coupled to the second differential output.

4. The driveline power-transmitting component of claim 3, wherein the first side gear and the first differential output are fixedly coupled to one another.

5. The driveline power transmitting component of claim 1, wherein the first and second friction clutches are disposed in series between the first differential output and an axial end of the differential input.

6. The driveline power transmission component of claim 1, further comprising a third friction clutch, a second biasing spring, and a fourth friction clutch, said third friction clutch having at least one friction plate non-rotatably but axially slidably coupled to said differential input, said second biasing spring urging said third friction clutch into an engaged condition, wherein said at least one friction plate of said third friction clutch is frictionally engaged with said second differential output, thereby resisting relative rotation between the second differential output and the differential input, the fourth friction clutch has a third plurality of clutch plates axially slidably but non-rotatably coupled to the differential input, and a plurality of fourth clutch plates interleaved with the third clutch plates and axially slidably but non-rotatably coupled to the second differential output.

7. The driveline power transmitting component of claim 6, wherein the third and fourth friction clutches are disposed in series between the first differential output and an axial end of the differential input.

8. A driveline power transmitting component comprising:

a differential assembly having a differential case, a differential gear set received in the differential case and having a pair of side gears, and a pair of clutch assemblies, each of the clutch assemblies being coupled to an associated one of the differential case and the side gears, each of the clutch assemblies being disposed in a torque path between the differential case and the associated one of the side gears;

wherein the differential assembly has a torque bias ratio that varies as a function of an amount of torque transmitted from the differential case to the side gears, wherein the clutch assembly is configured to create a step in the function in which the torque bias ratio increases with increasing amount of torque, wherein the torque bias ratio decreases with increasing amount of torque before the step in the function, and wherein the torque bias ratio decreases with increasing amount of torque after the step in the function.

9. A driveline power transmitting component comprising:

an input member;

a differential case driven by the input member, the differential case defining a cavity and being rotatable about an output axis;

a differential gear set received in the cavity, the differential gear set having a pair of side gears rotatable relative to the differential case about the output axis;

a pair of clutch packs received in the cavities, each of the clutch packs having a first friction clutch with at least one friction plate non-rotatably but axially slidably coupled to the differential case, a biasing spring urging the at least one friction plate into engagement with an associated one of the side gears to resist relative rotation between the first side gear and the differential case, and a second friction clutch having a plurality of first clutch plates axially slidably but non-rotatably coupled to the differential case, and a plurality of second clutch plates interleaved with the first clutch plates and axially slidably but non-rotatably coupled to the associated one of the side gears.

10. The power transmitting component of claim 8, wherein the input member comprises an input pinion shaft, and wherein the power transmitting component further comprises an input pinion coupled to the input pinion shaft for rotation therewith, and a ring gear meshed with the input pinion and rotationally coupled to the differential case.

11. The power transmitting component of claim 8, wherein the biasing spring of each of the clutch assemblies comprises a plurality of spring elements that are circumferentially spaced from one another about the output axis.

12. The power transmitting component of claim 11, wherein the spring element comprises a helical compression spring.

13. The power transmitting component of claim 8, wherein the differential gear set further comprises a plurality of differential pinions rotatably mounted on cross pins, the differential pinions meshing with the side gears.

14. The power transmitting component of claim 13, wherein the cross pin is coupled to the differential case to rotate with the differential case about the output axis.

Technical Field

The present disclosure relates to a power transmitting component having a limited slip differential assembly with a preloaded friction clutch.

Background

This section provides background information related to the present disclosure that is not necessarily prior art.

Limited slip differential assemblies are used to limit the speed differential between the output members of the differential assembly under certain conditions. Typically, a limited slip differential assembly will include one or more friction clutches or clutch assemblies, each clutch assembly providing a torque-carrying interface between a differential input, such as a differential case, and one of the differential output members, such as side gears. A spring may be used to preload the clutch assembly to provide a desired minimum torque carrying capacity. While such a preloaded limited slip differential assembly configuration is satisfactory for its intended purpose, a fixed minimum torque threshold for slip between the differential input and the differential output may be disadvantageous in some situations.

Disclosure of Invention

This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

In one form, the present disclosure provides a driveline power transmitting component having a differential assembly with a differential input, first and second differential outputs driven by the differential input, a first friction clutch, a first biasing spring, and a second friction clutch. The first friction clutch has at least one friction plate non-rotatably but axially slidably coupled to the differential input. The first biasing spring urges the first friction clutch into an engaged condition in which the at least one friction plate of the first friction clutch is frictionally engaged with the first differential output, thereby resisting relative rotation between the first differential output and the differential input. The second friction clutch has a plurality of first clutch plates axially slidably but non-rotatably coupled to the differential input and a plurality of second clutch plates interleaved with the first clutch plates and axially slidably but non-rotatably coupled to the first differential output.

In some forms the differential input is a differential case that houses the first differential output and the second differential output. Optionally, the differential assembly further comprises a differential gear set having a first side gear rotatably coupled to the first differential output and a second side gear rotatably coupled to the second differential output. In some forms the first side gear and the first differential output are fixedly coupled to one another.

In some forms the first and second friction clutches are disposed in series between the first differential output and an axial end of the differential input.

In some forms the driveline power transmission component further includes a third friction clutch, a second biasing spring, and a fourth friction clutch. The third friction clutch has at least one friction plate non-rotatably but axially slidably coupled to the differential input. The second biasing spring urges the third friction clutch into an engaged condition in which the at least one friction plate of the third friction clutch is frictionally engaged with the second differential output, thereby resisting relative rotation between the second differential output and the differential input. The fourth friction clutch has a plurality of third clutch plates axially slidably but non-rotatably coupled to the differential input and a plurality of fourth clutch plates interleaved with the third clutch plates and axially slidably but non-rotatably coupled to the second differential output. Optionally, the third and fourth friction clutches are arranged in series between the first differential output and an axial end of the differential input.

In another form, the present disclosure provides a driveline power transmitting component that includes a differential assembly having a differential case, a differential gear set, and a pair of clutch assemblies. The differential gear set is received in the differential case and has a pair of side gears. Each of the clutch assemblies is coupled to the differential case and an associated one of the side gears. Each of the clutch assemblies is disposed in a torque path between the differential case and an associated one of the side gears. The differential assembly has a torque bias ratio (torque bias ratio) that varies as a function of the amount of torque transmitted from the differential case to the side gears. The clutch assembly is configured to create a step (step) in the function in which the torque bias ratio increases as the amount of torque increases. The torque bias ratio decreases as the amount of torque increases before the step in the function. After the step in the function, the torque offset ratio decreases as the amount of torque increases.

In yet another form, the present disclosure provides a driveline power transmitting component having an input member, a differential case driven by the input member, a differential gear set, and a pair of clutch assemblies. The differential case defines a cavity and is rotatable about an output axis. The differential gear set is received in the cavity and includes a pair of side gears rotatable relative to the differential case about the output axis. The clutch assemblies are received in the cavities and each clutch assembly has a first friction clutch, a biasing spring, and a second friction clutch. The first friction clutch in each clutch assembly has at least one friction plate non-rotatably but axially slidably coupled to the differential case. The first biasing spring urges the at least one friction plate into engagement with an associated one of the side gears to resist relative rotation between the first side gear and the differential case. The second friction clutch has a plurality of first clutch plates axially slidably but non-rotatably coupled to the differential case, and a plurality of second clutch plates interleaved with the first clutch plates and axially slidably but non-rotatably coupled to the associated one of the side gears.

In some forms the input member is an input pinion shaft to which input pinions are coupled for rotation with the input pinion shaft, and a ring gear is meshed with the input pinions and rotationally coupled to the differential case.

In some forms, the biasing spring of each of the clutch assemblies includes a plurality of spring elements that are circumferentially spaced from one another about the output axis. Optionally, the spring element comprises a helical compression spring.

In some forms, the differential gear set includes a plurality of differential pinions rotatably mounted on a cross pin and meshing with the side gears. Optionally, the cross pin is rotatably coupled to the differential case.

Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

Drawings

The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

FIG. 1 is a perspective view, partially in section, of an example vehicle driveline component constructed in accordance with the teachings of the present disclosure;

FIG. 2 is a transverse cross-sectional view of a portion of the vehicle driveline component of FIG. 1 illustrating the differential assembly in greater detail; and is

FIG. 3 is a schematic diagram depicting TBR versus differential input torque for a prior art differential assembly and a differential assembly constructed in accordance with the teachings of the present disclosure.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

Detailed Description

Referring to FIG. 1, an example driveline power transmission component constructed in accordance with the teachings of the present disclosure is indicated generally by the reference numeral 10. In the particular example provided, the driveline power transmitting component 10 is a rear axle assembly, but it will be appreciated that the teachings of the present disclosure may be used in a variety of other driveline power transmitting components, including front axle assemblies, gearboxes, center differentials, and power take-off units. In the example provided, the driveline power transmission component 10 may include a housing 12, an input member 14, an input pinion 16, a ring gear 18, a differential assembly 20, and a pair of output shafts 22.

The housing 12 may define a cavity 30, and the input member 14, input pinion 16, ring gear 18, and differential assembly 20 may be received in the cavity 30. The housing 12 may support the input member 14 for rotation about an input axis 32. The input member 14 is configured as a shaft in the example provided, and the input pinion 16 may be coupled to the input member 14 for rotation therewith about an input axis 32. The ring gear 18 may be meshed with the input pinion 16 and may rotate about an output axis 34 that may be transverse (e.g., perpendicular) to the input axis 32.

Referring to fig. 2, differential assembly 20 may include a differential input 40, a differential gear set 42, and a pair of clutch assemblies 44.

Differential input 40 may be rotatably coupled to ring gear 18 and may be supported by housing 12 (fig. 1) for rotation about output axis 34. In the example provided, differential input 40 is a differential case defining a case cavity 48, and differential gear set 42 and clutch pack 44 may be received in case cavity 48.

Differential gear set 42 may have first and second differential outputs 50 and 52, respectively, which may be driven by differential input 40. Each of the first and second differential outputs 50, 52 has an internally toothed or splined bore 54 configured to axially slidably, but non-rotatably, engage a male splined segment 56 on an associated one of the output shafts 22.

The differential gear set 42 may be configured with helical gears and/or may be configured as a planetary gear set. In the example provided, differential gear set 42 includes a cross pin 60, a plurality of differential pinions 62, and a pair of side gears 64. Cross pin 60 may be rotatably coupled to differential input 40 and may extend through case cavity 48 along an axis perpendicular to output axis 34. The differential pinion gear 62 may be configured as a straight bevel gear and may be received in the differential cavity 30 and mounted for rotation on the cross pin 60. Each of the side gears 64 may be a straight bevel gear that may be received in the case cavity 48 for rotation about the output axis 34 and may mesh with the differential pinion gear 62. Each of the side gears 64 may be rotatably coupled to an associated one of the first and second differential outputs 50, 52, optionally fixedly coupled to an associated one of the first and second differential outputs 50, 52. In the example provided, each of the side gears 64 is integrally formed with an associated one of the first and second differential outputs 50, 52.

Each of the clutch assemblies 44 may include a first friction clutch 70, a biasing spring 72, and a second friction clutch 74. The first friction clutch 70 may have at least one friction plate 80 non-rotatably but axially slidably coupled to the differential input 40. If desired, the first friction clutch 70 may have a first plurality of friction plates that may be non-rotatably but axially slidably coupled to the differential input 40, and a second plurality of friction plates that may be non-rotatably but axially slidably coupled to one of the first and second differential outputs 50, 52.

A biasing spring 72 may be disposed between the differential input 40 and the first friction clutch 70, and may urge the first friction clutch 70 into an engaged condition, wherein at least one friction plate 80 is frictionally engaged with an associated one of the first and second differential outputs 50, 52, thereby resisting relative rotation between the associated one of the first and second differential outputs 50, 52 and the differential input 40. In this regard, the biasing spring 72 preloads the first friction clutch 70 such that relative rotation between the associated one of the first and second differential outputs 50, 52 and the differential input 40 is inhibited if the difference between the amount of torque input to the differential input 40 and the amount of torque output from the associated one of the first and second differential outputs 50, 52 is less than or equal to a first torque threshold. The biasing spring 72 may include one or more spring elements 84, each of which may be configured as a wave spring or a helical coil compression spring. In the example provided, the biasing spring 72 includes a plurality of spring elements 84, the plurality of spring elements 84 being configured as helical coil compression springs, and the plurality of spring elements 84 being received in the case cavity 48 and being circumferentially spaced from one another about the output axis 34.

Second friction clutch 74 may have a plurality of first clutch plates 90 axially slidably but non-rotatably coupled to differential input 40, and a plurality of second clutch plates 92 interleaved with first clutch plates 90 and axially slidably but non-rotatably coupled to an associated one of first and second differential outputs 50, 52. The second friction clutch 74 may be disposed on an opposite side of the first friction clutch 70 from the associated one of the first and second differential outputs 50, 52. The first and second clutch plates 90, 92 of the second friction clutch 74 are not biased into engagement such that the second friction clutch 74 has no or relatively little effect on the operation of the differential assembly 20 when relatively little torque is transmitted from the differential input 40 to the associated one of the first and second differential outputs 50, 52.

In operation, the first friction clutch 70 inhibits relative rotation between the differential input 40 and the associated one of the first and second differential outputs 50, 52 until the amount of torque transmitted through the first clutch assembly 70 exceeds a first predetermined threshold. As the amount of torque transmitted from the differential input 40 to the first and second differential outputs 50, 52 increases, the thrust forces acting on the first and second differential outputs 50, 52 tend to drive the first and second differential outputs 50, 52 axially away from each other along the output axis 34. When the thrust force is sufficiently large, the thrust force will overcome the biasing spring 72 and will drive the first and second clutch plates 90, 92 of the second friction clutch 74 into frictional engagement with one another.

Referring to FIG. 3, a first curve 100 depicts a Torque Bias Ratio (TBR) of a prior art limited slip differential assembly as a function of an amount of torque input to the prior art limited slip differential assembly. The limited slip differential assembly of the prior art is a conventional preloaded limited slip differential assembly having a (single) friction clutch that is preloaded with a preload spring. The first curve 100 generally follows a function in which TBR is inversely related to the square of the amount of torque input to the limited slip differential assembly of the prior art (i.e., TBR ═ 1/(TQ)²+ C, where TQ is the amount of differential input torque, and C is a constant).

A second curve 102 depicts the TBR of a limited slip differential assembly constructed in accordance with the teachings of the present disclosure. The second curve 102 has four different line segments 110, 112, 114 and 116. The line segment 110 is very steep relative to the corresponding portion of the first curve 100, the difference being due to the relatively low torque capacity of the first friction clutch 70 (fig. 2). The line segment 112 occurs where the thrust forces on the first and second differential outputs 50, 52 (fig. 2) are driving the first and second differential outputs 50, 52 (fig. 2) away from each other and compressing the biasing spring 72 (fig. 2). Line segment 114 occurs where the thrust forces on the first and second differential outputs 50 and 52 (fig. 2) are driving the first and second clutch plates 90 and 92 (fig. 2) into engagement with one another. Line segment 116 occurs where the thrust forces on first and second differential outputs 50 and 52 (fig. 2) are greater than or equal to the thrust forces required to fully engage first and second clutch plates 90 and 92 (fig. 2) of second friction clutch 74 (fig. 2) to one another.

The foregoing description of the embodiments has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The individual elements or features may also be varied in a number of ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

The claims (modification according to treaty clause 19)

1. A driveline power transmitting component (10), comprising:

a differential assembly (20) having a differential input (40), first and second differential outputs (50, 52) driven by the differential input (40), a first friction clutch (70), a first biasing spring (72) and a second friction clutch (74), the first friction clutch (70) having at least one friction plate (80) non-rotatably but axially slidably coupled to the differential input (40), the first biasing spring (72) urging the first friction clutch (70) into an engaged condition, wherein the at least one friction plate (80) of the first friction clutch (70) is frictionally engaged with the first differential output (50) to resist relative rotation between the first differential output (50) and the differential input (40), the second friction clutch (74) has a first plurality of clutch plates (90) axially slidably but non-rotatably coupled to the differential input (40), and a second plurality of clutch plates (92) interleaved with the first clutch plates (90) and axially slidably but non-rotatably coupled to the first differential output (50).

2. The driveline power transmitting component (10) of claim 1, wherein the differential input (40) is a differential case housing the first differential output (50) and the second differential output (52).

3. The driveline power transmitting component (10) of claim 2, wherein the differential assembly (20) further comprises a differential gear set (42) having a first side gear (64) rotatably coupled to the first differential output (50) and a second side gear (64) rotatably coupled to the second differential output (52).

4. The driveline power transmitting component (10) of claim 3, wherein the first side gear (64) and the first differential output (50) are fixedly coupled to one another.

5. The driveline power transmitting component (10) of claim 1, wherein the first friction clutch (70) and the second friction clutch (74) are disposed in series between the first differential output (50) and an axial end of the differential input (40).

6. The driveline power transmitting component (10) of claim 1, further comprising a third friction clutch (70), a second biasing spring (72), and a fourth friction clutch (74), the third friction clutch (70) having at least one friction plate (80) non-rotatably but axially slidably coupled to the differential input (40), the second biasing spring (72) urging the third friction clutch (70) into an engaged condition in which the at least one friction plate (80) of the third friction clutch (70) is frictionally engaged with the second differential output (52) to resist relative rotation between the second differential output (52) and the differential input (40), the fourth friction clutch (74) having a plurality of third clutch plates (90) axially slidably but non-rotatably coupled to the differential input (40), and a plurality of fourth clutch plates (92) interleaved with the third clutch plates (90) and axially slidably but non-rotatably coupled to the second differential output (50).

7. The driveline power transmitting component (10) of claim 6, wherein the third friction clutch (70) and the fourth friction clutch (74) are disposed in series between the second differential output (52) and an axial end of the differential input (40).

8. The driveline power transmitting component (10) of claim 1, wherein the differential input (40) is a differential case, wherein the differential assembly (20) includes a differential gear set (42) received in the differential case, wherein the differential gear set (42) includes a first side gear (64) and a second side gear (64), the first side gear (64) being the first differential output (50), the second side gear (64) being the second differential output (52), the first friction clutch (70) disposed in a first torque path between the differential case and the first side gear (64), the second friction clutch (74) disposed in a second torque path between the differential case and the first side gear (64);

wherein the differential assembly (20) has a torque bias ratio that varies as a function of an amount of torque transmitted from the differential case to the first and second side gears (64, 64), wherein the first and second friction clutches (70, 74) are configured to create a step in the function that increases in the torque bias ratio as the amount of torque increases, wherein the torque bias ratio decreases as the amount of torque increases before the step in the function, and wherein the torque bias ratio decreases as the amount of torque increases after the step in the function.

9. A driveline power transmitting component (10), comprising:

an input member (14);

a differential case (40) driven by the input member (14), the differential case (40) defining a cavity (48) and being rotatable about an output axis (34);

a differential gear set (42) received in the cavity (48), the differential gear set (42) having a pair of side gears (64) rotatable relative to the differential case about the output axis (34);

a pair of clutch packs (44) received in the cavities (48), each of the pair of clutch packs (44) having a first friction clutch (70), a biasing spring (72), and a second friction clutch (74), the first friction clutch (70) having at least one friction plate (80) non-rotatably but axially slidably coupled to the differential case (40), the biasing spring (72) urging the at least one friction plate (80) into engagement with an associated one of the side gears (64) to resist relative rotation between the associated one of the side gears (64) and the differential case (40), the second friction clutch (74) having a plurality of first clutch plates (90) axially slidably but non-rotatably coupled to the differential case (40), and a plurality of first clutch plates (90) interleaved with and axially slidably but non-rotatably coupled into the side gears (64) A plurality of second clutch plates (92) of the associated one.

10. The power transmitting component of claim 9, wherein the input member (14) comprises an input pinion shaft, and wherein the power transmitting component further comprises an input pinion (16) coupled to the input pinion shaft for rotation therewith, and a ring gear (18) meshed with the input pinion (16) and rotationally coupled to the differential case (40).

11. The power transmitting component of claim 9, wherein the biasing spring (72) of each of the pair of clutch assemblies (44) includes a plurality of spring elements (84), the plurality of spring elements (84) being circumferentially spaced from one another about the output axis (34).

12. The power transmitting component of claim 11, wherein the plurality of spring elements (84) comprise helical compression springs.

13. The power transmitting component of claim 9, wherein the differential gear set (42) further comprises a plurality of differential pinions (62) rotatably mounted on a cross pin (60), the differential pinions (62) meshing with the pair of side gears (64).

14. The power transmitting component of claim 13, wherein the cross pin (60) is coupled to the differential case (40) to rotate with the differential case (40) about the output axis (34).