Patent Application
20110048889
The present disclosure generally relates to torque transmission components, and more particularly relates to clutch plates.
Torque transmission members such as clutch plates are widely known in the art. In vehicles, for example, various types of clutches have been used to transmit torque, such as an automatic transmission which may use multiple clutches to engage or disengage selected gearsets, thereby to obtain a desired gear ratio. The clutches provided for this purpose are typically friction plate clutches, which include a plurality of inner or drive plates that are splined to a rotatable hub. A housing or case is coaxially aligned with the hub and supported for rotation independent of the hub. A plurality of outer or driven plates are splined to the housing or case and are interposed between the drive plates, such that the drive and driven plates are alternately arranged on a common axis. The drive plates include a friction material on one or both sides of the plates. An actuator, such as a hydraulic piston, applies a pressure force that presses the drive and driven plates into engagement, thereby permitting torque to be transferred from the hub to the housing.
The above-described clutch plates typically use spline teeth to couple the plate to an associated rotatable member. The spline teeth are configured to slide along grooves formed in the rotatable member. Additionally, the spline teeth provide the points of contact between the clutch plate and the rotatable member, and therefore they encounter a significant amount of contact stress. In most conventional clutch plates, the spline teeth are formed as extensions of a central, annular body. Accordingly, the thickness of the entire clutch plate is typically selected according to the amount of contact stress expected at the spline teeth. This may result in the body portion of the clutch plate being oversized, which may increase clutch plate weight and rotating inertia, thereby adversely impacting clutch design. Additionally, thicker clutch plates may require additional space, thereby increasing the size of the transmission or other component in which they are used.
In accordance with one aspect the disclosure, a clutch plate is provided for transmitting torque from a driving member to a driven member. The clutch plate may include an annular body disposed around an axis and defining inner and outer edges, the annular body having a thickness “t”. A plurality of spline teeth may project radially from the annular body, each spline tooth including a tab extending from the annular body and a flap superposed over the tab, in which each spline tooth has a thickness “T” approximately twice the body thickness “t”.
According to other aspects of this disclosure, a clutch plate may include an annular body disposed around an axis and defining inner and outer edge, and a plurality of spline teeth projecting radially from the annular body. Each spline tooth may have a tab extending from the annular body, a flap superposed over the tab, and a joint extending between the tab and the flap. The joint may define a fold line extending substantially circumferentially about the body axis.
According to further aspects of this disclosure a clutch plate may include an annular body disposed around an axis and defining inner and outer edges, the annular body having a thickness “t”, and a plurality of spline teeth projecting radially from the annular body. Each spline tooth may have a tab aligned with and extending from one of the inner and outer edges of the annular body, each tab including first and second side edges, a flap superposed over the tab so that each spline tooth has a thickness “T” approximately twice the body thickness “t”, each flap including first and second side edges, and a joint extending between the tab and the flap, the joint defining a fold line extending substantially circumferentially about the body axis. Each tab and flap have substantially the same overall shape so that each spline tooth includes a first composite side edge formed by the tab first edge and flap first edge and a second composite side edge formed by the tab second side edge and the flap second side edge.
These and other aspects and features of the disclosure will become more apparent upon reading the following detailed description when taken into consideration in conjunction with the accompanied drawings.
While the present disclosure is susceptible to various modifications and alternative constructions, certain illustrative embodiments thereof are shown in the drawings and are described below in detail. It should be understood, however, that there is no intention to limit the present disclosure to the specific forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the spirit of the scope of the present disclosure.
A clutch plate is disclosed herein that includes reinforced spline teeth. The clutch plate includes a body portion having a thickness, and the spline teeth have a thickness that is approximately twice the thickness of the body portion. In certain embodiments, each spline tooth may include a tab portion and a flap portion that is superposed over the tab portion. The flap portion may be joined to the tab portion by a circumferential fold line. The increased thickness of the spline teeth reduces contact stress in the spline teeth while permitting a reduced thickness body portion, thereby reducing overall clutch plate weight and associated rotating inertia to improve clutch performance. Additionally, the smaller body portion thickness reduces the amount of space required for the torque transmission component in which the clutch plate is used.
Referring now to the drawings,
As shown in
Referring still to
The inner and outer clutch plates 38, 42 are allowed to slide in an axial direction while remaining attached to and rotating with the hub 28 and housing 32, respectively. Accordingly, the plates 38, 42 are movable between an unengaged position, in which the plates 38, 42 do not contact each other, and a torque transmitting position, in which the plates 38, 42 engage each other with sufficient force to transmit torque from the inner plates 38 to the outer plates 42. An actuator 44 may be operatively coupled to the clutch plates 38, 42 to move them between the unengaged and torque transmitting positions.
The inner clutch plate 38 is shown in greater detail in
Each spline tooth 58 may have a greater thickness than the body 50 to reduce contact stresses during torque transmission. In the illustrated embodiment, each spline tooth 58 includes a tab 60 and a flap 62. The tab 60 may be aligned with and extend inwardly from the body 50. The flap 62 is superposed over the tab 60. The tab 60 and flap 62 may be coupled by a joint 64 that defines a fold line 66 extending circumferentially about the body axis 52. The tab 60 and flap 62, therefore, may be formed integrally with the body 50, with the flap 62 being folded over to overlie the tab 60. Accordingly, each spline tooth 58 may have a thickness “T” that is approximately twice the body thickness “t”.
One of the spline teeth 58 is shown in
When the flap 62 is folded over the tab 60, the resulting spline tooth 58 has first and second composite side edges 76, 78. The first composite side edge 76 is formed by the juxtaposition of the tab first side edge 68 and the flap first side edge 72, while the second composite side edge 78 is similarly formed by the tab second side edge 70 and the flap second side edge 74. The tab 60 and flap 62 may have substantially the same overall shapes so that the resulting first and second composite side edges 76, 78 of each spline tooth 58 are substantially contiguous and smooth, thereby to reduce localized areas of stress and more efficiently transmit torque from the torque transmission component to the clutch plate, or vice versa.
More specifically, the outer clutch plate 42 includes an annular body 82 disposed about an axis 84. The body 82 includes an inner edge 86 and an outer edge 88. The spline teeth 80 extend outwardly from the body outer edge 88. As best shown in
Any of the spline tooth embodiments discussed above may further include an optional fastener for holding the flap in place against the tab. The fastener may be provided in any of form suitable for securing the flap in the folded position, including, but not limited to, staking, gluing, welding, and riveting.
While the foregoing embodiments are described as including a flap that is integrally provided with the tab, it will be appreciated that the flap may be provided as a separate component which is then fastened to the tab. Accordingly, the term “superposed” as used herein and in the claims includes portions of an integral component or two separate components that are folded or otherwise placed adjacent or in contact with one another.
The foregoing provides a clutch plate that can advantageously be used in a vehicle transmission or other torque transfer application. The clutch plate includes spline teeth that are reinforced by having a thickness that is larger than that of a body portion, thereby reducing contact stress in the spline teeth. The clutch plates disclosed herein further permit the use of a reduced thickness body portion for a given application, thereby reducing overall clutch plate weight and associated rotating inertia to improve clutch performance. Additionally, the smaller body portion thickness reduces the amount of space required for the torque transmission component in which the clutch plate is used.
This application is a non-provisional claiming priority under 35 USC §119 (e) to U.S. Provisional Patent Application No. 61/238,340 filed on Aug. 31, 2009.
| Number | Date | Country | |
|---|---|---|---|
| 61238340 | Aug 2009 | US |
