Vehicle driveline component having friction clutch

Abstract

A vehicle drive line component including a friction clutch, configured to selectively communicate rotational motion between the first plate mount and the second plate mount, comprising: a clutch pack having a plurality of first clutch plates axially slidable but non-rotatable relative to the first plate mount, a plurality of second clutch plates, interleaved with the first clutch plates, axially slidable but non-rotatable relative to the second plate mount; a pressure plate, disposed on a side of the clutch pack, comprising: a hub portion; an engagement portion that is configured to contact the clutch pack; and a flange portion that extends radially outwardly from the hub portion, wherein the flange portion includes: a flange body; a first transition portion coupling the hub portion to a radially inner side of the flange body; and a second transition portion that couples the engagement portion to a radially outer side of the flange body.

Description

[0001] VEHICLE DRIVELINE COMPONENT HAVING FRICTION CLUTCH

[0002] REFERENCE TO RELATED APPLICATIONS

[0003] This application claims the benefit of U.S. Provisional Serial No. 63 / 559,540 filed on February 29, 2024 the entire contents of which are incorporated herein by reference in its entirety.

[0004] TECHNICAL FIELD

[0005] The present disclosure relates to a vehicle driveline component having a friction clutch.

[0006] BACKGROUND

[0007] This section provides background information related to the present disclosure which is not necessarily prior art.

[0008] Friction clutches are commonly employed in various vehicle driveline components, such as transfer cases, electric drive units, power take-off units, torque transfer couplings, and axle assemblies to selectively transfer rotary power between two components of the vehicle driveline component. Such friction clutches commonly include a clutch hub, a clutch drum, a clutch pack and a pressure plate. The clutch pack includes first clutch plates, which are axially slidably but non-rotatably coupled to the clutch hub, and a plurality of second clutch plates that are interleaved with the first clutch plates and axially slidably but non-rotatably coupled to the clutch drum. Each of the first clutch plates and / or each of the second clutch plates can include an annular steel plate and a friction material that is adhered to the annular steel plate. The pressure plate can be axially slidably but non-rotatably coupled to either the clutch hub or the clutch drum and can be translated along the rotational axis of the friction clutch to selectively compress the clutch pack to permit torque transmission between the first and second clutch plates.

[0009] It is relatively common to specify a torque curve for a friction clutch that is used in a vehicle driveline component. In brief, the torque curve associates the position of the pressure plate (relative to a kiss point) with the amount of torque that the friction clutch is able to transmit. When a friction clutch is designed to perform within acceptable limits of a predetermined torque curve, the friction clutch can be integrated into the vehicle driveline component without a need for empirically determining the actual torque curve of the friction clutch and thereafter calibrating the controller that operates the actuator of the friction clutch to compensate for differences between the actual torque curve and the design target torque curve.

[0010] Heretofore, it has been a significant challenge to design a relatively lowcost friction clutch that is robust, easily manufactured, and has an actual torque curve that matches the design target torque curve. With reference to Figure 9, an exemplary prior art friction clutch 2 is illustrated in cross-section and under a predetermined load. Bending of various components within the friction clutch 2, including a conventional pressure plate 4, can cause some of the clutch plates 6a, 6b in the friction clutch 2 to bind rather than slide in an axial direction. When such binding occurs, the clutch plates 6a, 6b that experience binding transmit relatively less torque than the clutch plates 6a, 6b that do not experience binding so that the actual torque curve of the friction clutch 2 deviates from the design target torque curve. This situation cannot be rectified by merely exerting more force onto the clutch plates 6a, 6b as this would tend to overload the clutch plates 6a, 6b that are not experiencing binding and more significantly, does not change the actual torque curve of the friction clutch 2 so that it would match the design target torque curve.

[0011] One proposed solution adds clutch plates 6a, 6b into the friction clutch 2. Unfortunately, the addition of clutch plates 6a, 6b to the friction clutch 2 increases the cost of the friction clutch 2 as well as the physical size of the friction clutch 2.

[0012] Consequently, there remains a need in the art for an improved friction clutch whose actual torque curve is easily modifiable to conform to a design target torque curve. SUMMARY

[0013] According to one aspect of the disclosure, a vehicle driveline component includes a first plate mount! a second plate mount! a friction clutch, configured to selectively communicate rotational motion between the first plate mount and the second plate mount, comprising: a clutch pack having a plurality of first clutch plates axially slidable but non-rotatable relative to the first plate mount, a plurality of second clutch plates, interleaved with the first clutch plates, axially slidable but non-rotatable relative to the second plate mount! a pressure plate, disposed on a side of the clutch pack, comprising: a hub portion! an engagement portion that is configured to contact the clutch pack! and a flange portion that extends radially outwardly from the hub portion, wherein the flange portion includes: a flange body! a first transition portion coupling the hub portion to a radially inner side of the flange body! and a second transition portion that couples the engagement portion to a radially outer side of the flange body.

[0014] According to another aspect of the disclosure, a vehicle driveline component a first shaft supported for rotation about a first axis! a second shaft supported for rotation about a second axis! a first plate mount coupled to the first shaft! a second plate mount included with a clutch drum rotatably coupled with the second shaft! a friction clutch, configured to selectively communicate rotational motion between the first plate mount and the second plate mount, comprising: a clutch pack having a plurality of first clutch plates axially slidable but non-rotatable relative to the first plate mount, a plurality of second clutch plates, interleaved with the first clutch plates, axiallyslidable but non-rotatable relative to the second plate mount! a pressure plate, disposed on a side of the clutch pack, comprising: a hub portion! an engagement portion that is configured to contact the clutch pack! and a flange portion that extends radially outwardly from the hub portion, wherein the flange portion includes: a flange body! a first transition portion coupling the hub portion to a radially inner side of the flange body! and a second transition portion that couples the engagement portion to a radially outer side of the flange body. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] 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.

[0016] Figure 1 is a perspective view of an exemplary vehicle drive line component having a friction clutch that is constructed in accordance with the teachings of the present disclosure;

[0017] Figure 2 is a section view taken through the vehicle driveline component of Figure 1;

[0018] Figures 3 and 3A are enlarged portions of Figure 4;

[0019] Figure 4 is an exploded perspective views of a portion of the vehicle driveline component of Figure 1 illustrating the configuration of a friction clutch;

[0020] Figure 5 is a perspective view of a portion of the friction clutch illustrating a pressure plate;

[0021] Figure 6 is a section view taken along the line 6-6 of Figure 5;

[0022] Figure 7 is a section view taken along the line 7-7 of Figure 5;

[0023] Figure 8 is a section view similar to that of Figure 3 but illustrating the friction clutch with a predetermined load being applied through the pressure plate; and

[0024] Figure 9 is a section view of a prior art friction clutch with a predetermined load being applied through a conventional pressure plate to a clutch pack.

[0025] Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

[0026] DETAILED DESCRIPTION

[0027] With reference to Figure 1, an exemplary vehicle driveline component constructed in accordance with the teachings of the present disclosure is generally indicated by reference numeral 10. The vehicle driveline component 10 is illustrated to be a transfer case of the type that is selectively operable in a 2-wheel drive mode and a 4-wheel drive mode. It will be appreciated, however, that the teachings of the present disclosure have application to various other types of driveline components, including power take-off units, axle assemblies, electro- hydraulic clutches (e.g., a Haldex® coupling manufactured by BorgWarner Inc. of Auburn Hills, Michigan) and electric drive units.

[0028] With reference to Figure 2, the vehicle driveline component 10 can include a housing 12, a first shaft 14, a second shaft 16, a friction clutch 18, a drive element 20, a driven element 22, an endless power transmitting component 24, and a clutch actuator 26. The housing 12 can comprises first and second housing halves 40 and 42, respectively, that can be fastened together to define an internal cavity 44 into which the first and second shafts 14 and 16, the friction clutch 18, the drive and driven elements 20 and 22, the endless power transmitting component 24, and the clutch actuator 26 can be received.

[0029] The first shaft 14 can be supported for rotation about a first axis 50 relative to the housing 12 by suitable bearings 52. In the example provided, the first shaft 14 has a reduced diameter end 54 and a female splined output end (not shown). The reduced diameter end 54 is configured to nest inside a planet carrier of a two- speed planetary reduction that serves as the input to the vehicle driveline component 10. One of the bearings 52 (a needle bearing in the example shown) can rotationally support the first shaft 14 for rotation relative to the planet carrier. It will be appreciated that the two-speed planetary reduction outputs rotary power to the first shaft 14 and can be operated in a first speed ratio, in which the first shaft 14 is coupled for rotation with the planet carrier, and a second speed ratio where the first shaft 14 is driven at a reduced rotational speed relative to the planet carrier. It will also be appreciated that the planetary reduction could be eliminated altogether so that the first shaft 14 would directly receive a rotary input (i.e., the first shaft 14 would be the input of the vehicle driveline component 10 rather than the planet carrier). The output end of the first shaft 14 can be coupled to a propshaft (not shown) in a conventional manner to transmit rotary power to a rear axle assembly (not shown).

[0030] The second shaft 16 can be supported for rotation about a second axis 60 relative to the housing 12 by a pair of second bearings 62. The second axis 60 can be parallel to the first axis 50. The second shaft 16 can have a female splined output end 66 that can be configured to engage a male splined end (not shown) of a shaft (not shown) that transmits rotary power to a front axle assembly (not shown).

[0031] With reference to Figures 3 and 4, the friction clutch 18 can include a clutch hub 70, a clutch drum 72, a clutch pack 73, which has a plurality of first clutch plates 74 and a plurality of second clutch plates 76, and a pressure plate 78. The clutch hub 70 can be a sleevedike structure and can have a female splined aperture 80, which is received on and engaged to a male splined segment 14a of the first shaft 14, and a first plate mount 82. The clutch hub 70 can float axially (i.e., along the first axis 50) on the first shaft 14 or one or more snap rings (not shown) could be employed to limit axial movement of the clutch hub 70 on the first shaft 14 in a desired direction or directions. The first plate mount 82 can have a radially outer surface with a plurality of spline teeth 102 formed thereon. A plurality of clutch plate lubricant passages (not shown) can be formed radially through the clutch hub 70 to permit lubricant to flow through the first plate mount 82 to lubricate the friction clutch 18.

[0032] The clutch drum 72 can be a drumdike structure having a second plate mount 110 and an annular wall member 112. The second plate mount 110 can be a circumferentially extending wall that is disposed concentrically about the first plate mount 82. The second plate mount 110 can have an inner circumferential surface, which can have a plurality of spline teeth 114 formed thereon. The annular wall member 112 can extend radially inwardly from the second plate mount 110.

[0033] The first clutch plates 74 can be axially slidably but non-rotatably coupled to the first plate mount 82. In the example provided, the first clutch plates 74 conventionally have a plate member 116 and a plurality of sets of friction material 118 that are bonded to the opposite faces of the plate member 116. The friction material 118 can be unitarily formed in an annular manner, or could be formed in two or more segments. If the friction material is formed in two or more segments, the ends of the segments may optionally be coupled to one another so that the segments cooperate to form a continuous annular ring. The friction material 118 is mounted to each face of the plate member 116 at or relatively close to the outer circumferential edge of the plate member 116. The plate member 116 can define a splined aperture 120 that defines a plurality of spline teeth. The first plate mount 82 of the clutch hub 70 is received into the splined aperture 120 such that the spline teeth 102 of the first plate mount 82 meshingly engage the spline teeth of the splined aperture 120 to thereby rotationally couple the first clutch plates 74 to the clutch hub 70.

[0034] The second clutch plates 76 can be interleaved with the first clutch plates 74 and can be axially slidably but non-rotatably coupled to the second plate mount 110. In the example provided, the second clutch plates 76 conventionally have an outer circumferential surface that defines a plurality of spline teeth and the second clutch plates 76 are received into the second plate mount 110 such that the spline teeth of the second clutch plates 76 meshingly engage the spline teeth 114 of the second plate mount 110 to thereby rotationally couple the second clutch plates 76 to the clutch drum 72.

[0035] The pressure plate 78 is disposed on a side of the clutch pack 73 that is opposite the radial wall 84 of the clutch hub 70 and can be movable along the first axis 50 to selectively apply a compressive force to the clutch pack 73, which causes frictional engagement between the first and second clutch plates 74 and 76. If desired, the pressure plate 78 can be non-rotatably but axially slidably coupled directly to the clutch hub 70 or directly to the clutch drum 72. In the example provided, the pressure plate 78 is not directly engaged to either of the clutch hub 72 or the clutch drum 72, but is engagable to the first clutch plates 74, as will be discussed in more detail below, to limit rotation of the pressure plate 78 relative to the first clutch plates 74 and the clutch hub 70.

[0036] With reference to Figures 4 through 7, the pressure plate 78 has a hub portion 130, a flange portion 131, which extends radially outwardly from the hub portion 130, and an engagement portion 132 that is configured to contact the clutch pack 73. The hub portion 130 defines a hub aperture 134 that is received over the first shaft 14 (Fig. 2). In the example provided, the hub aperture 134 is smaller in diameter than the clutch hub 70. The flange portion 131 is coupled to and extends radially between the hub portion 130 and the engagement portion 132. The flange portion 131 can include a flange body 140, a first transition portion 142, which couples the hub portion 130 to a radially inner side of the flange body 140, and a second transition portion 144 that can couple the engagement portion 132 to a radially outer side of the flange body 140. In the example provided, the flange body 140 is generally perpendicular to the first axis 50 when the pressure plate 78 is not compressing the clutch pack 73. Optionally, the flange portion 131 can include a plurality of tabs 148 that extend perpendicularly from the flange body 140 into the clutch pack 73. More specifically, the tabs 148 extend from the flange body 140 and are received through corresponding tab apertures 150 formed in the plate members 116 of the first clutch plates 74. It will be appreciated that contact between the tabs 148 and the sides of the tab apertures 150 effectively limits relative rotation between the pressure plate 78 and the first clutch plates 74 as well as the clutch hub 70. The engagement portion 132 can be formed as a relatively short hollow cylindrical segment that extends from a distal end of the second transition portion 144. The engagement portion 132 can be disposed coaxially about the first axis 50 concentric with the clutch hub 70 and defines an engagement face 154 that is annular in shape and perpendicular to the first axis 50.

[0037] The pressure plate 78 is formed of a steel sheet metal material in a suitable stamping process (e.g., with a progressive die). The deformation of the steel sheet metal material in the forming process can work harden the pressure plate 78 to provide desired strength. Optionally, the pressure plate 78 could be heat treated for increased strength. We have found good results when the thicknesses of the steel sheet metal material is greater than or equal to 3mm, and preferably greater than or equal to 4mm.

[0038] With reference to Figures 3 through 5, the pressure plate 78 is formed so that the engagement face 154 has a relatively narrow width and has an outer diameter that is relatively close to the diameter of the first clutch plates 74. In the example provided, the engagement face has a width W of about 4mm. The relatively small contact area over which the pressure plate 78 makes contact with the first clutch plates 74, along with the positioning of the contact as far radially outwardly on the first clutch plates 74 as is possible, greatly improves the ability of the pressure plate 78 to apply uniform and consistent force to the first clutch plates 74 when relatively high forces are transmitted from the pressure plate 78 to the first clutch plate 74.

[0039] With reference to Figure 8, the application of a relatively high force to the pressure plate 78 is associated with relatively little tipping of the first clutch plates 74. Consequently, the binding between or pinching together of the first clutch plates 74 and the second clutch plates 76 can be significantly reduced relative to the prior art so that the friction clutch 18 is able to transmit a relatively higher amount of torque than the prior art configuration that is depicted in Figure 9.

[0040] The foregoing description of the embodiments has been provided for 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 same may also be varied in many 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.

Claims

What is claimed is:

1. A vehicle driveline component, comprising: a first plate mount; a second plate mount; a friction clutch, configured to selectively communicate rotational motion between the first plate mount and the second plate mount, comprising: a clutch pack having a plurality of first clutch plates axially slidable but non-rotatable relative to the first plate mount, a plurality of second clutch plates, interleaved with the first clutch plates, axially- slidable but non-rotatable relative to the second plate mount; a pressure plate, disposed on a side of the clutch pack, comprising: a hub portion; an engagement portion that is configured to contact the clutch pack; and a flange portion that extends radially outwardly from the hub portion, wherein the flange portion includes: a flange body; a first transition portion coupling the hub portion to a radially inner side of the flange body; and a second transition portion that couples the engagement portion to a radially outer side of the flange body.

2. The vehicle driveline component of claim 1, further comprising a plurality of spline teeth formed on the first plate mount and the second plate mount.

3. The vehicle driveline component of claim 1, further comprising a clutch hub configured to rotatably couple to a first shaft and form a portion of the second plate mount.

4. The vehicle driveline component of claim 1, wherein the pressure plate is non-rotatably but axially slidably coupled to a clutch hub or a clutch drum.

5. The vehicle driveline component of claim 1, further comprising a plurality of tabs extending perpendicular to the flange body and through corresponding tab apertures formed in the first clutch plates.

6. The vehicle driveline component of claim 1, wherein the engagement portion is a hollow cylindrical segment that extends from a distal end of the second transition portion.

7. The vehicle driveline component of claim 1, wherein the engagement portion further comprises an engagement face that is annular in shape.

8. A vehicle driveline component, comprising: a first shaft supported for rotation about a first axis; a second shaft supported for rotation about a second axis; a first plate mount coupled to the first shaft; a second plate mount included with a clutch drum rotatably coupled with the second shaft; a friction clutch, configured to selectively communicate rotational motion between the first plate mount and the second plate mount, comprising: a clutch pack having a plurality of first clutch plates axially slidable but non-rotatable relative to the first plate mount, a plurality of second clutch plates, interleaved with the first clutch plates, axially- slidable but non-rotatable relative to the second plate mount; a pressure plate, disposed on a side of the clutch pack, comprising: a hub portion; an engagement portion that is configured to contact the clutch pack; and a flange portion that extends radially outwardly from the hub portion, wherein the flange portion includes: a flange body; a first transition portion coupling the hub portion to a radially inner side of the flange body; anda second transition portion that couples the engagement portion to a radially outer side of the flange body.

9. The vehicle driveline component of claim 8, further comprising and endless loop coupling rotational motion from the first shaft to the second shaft.

10. The vehicle driveline component of claim 8, further comprising a plurality of spline teeth formed on the first plate mount and the second plate mount.

11. The vehicle driveline component of claim 8, further comprising a clutch hub configured to rotatably couple to a first shaft and form a portion of the second plate mount.

12. The vehicle driveline component of claim 8, wherein the pressure plate is non-rotatably but axially slidably coupled to a clutch hub or a clutch drum.

13. The vehicle driveline component of claim 8, further comprising a plurality of tabs extending perpendicular to the flange body and through corresponding tab apertures formed in the first clutch plates.

14. The vehicle driveline component of claim 8, wherein the engagement portion is a hollow cylindrical segment that extends from a distal end of the second transition portion.

15. The vehicle driveline component of claim 8, wherein the first axis is not coaxial with the second axis.

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