Patent Application
20190128341
The present disclosure relates to a wedge clutch for selectively coupling two or more powertrain components to each other.
In a motor vehicle, a four-wheel drive system or an all-wheel drive system can be selectively activated by a clutch. The clutch can be part of a power transfer unit for connecting a power source to a secondary drive shaft when it is desired to deliver power to the secondary drive shaft. It is known that such a clutch can be a dog clutch. Dog clutches are prone to teeth clash or blocking. It is also known that such a clutch can be a wet clutch in a differential. Pressurized fluid must be continuously supplied to keep the clutches in a closed mode, adding to the power usage associated with usage of the clutch.
Recently, wedge clutches are being developed as an alternative structure for coupling an input shaft to an output shaft. Wedge clutches are known, such as those described in U.S. Patent Publication Numbers 2015/0083539, 2015/0014113, and 2015/0152921. A wedge clutch may include an inner race connected to one of the shafts, and an outer race connected to the other of the shafts. A wedge plate is radially disposed between the inner and outer races and is configured to engage the inner and outer races when the clutch is locked to transmit power from the input shaft to the output shaft.
According to one embodiment, a wedge clutch includes an inner race rotatable about an axis, and an outer race concentric with the inner race and rotatable about the axis. A plurality of wedge segments are arranged about the axis, are circumferentially separated from each other, and collectively form an annular wedge plate disposed between the inner and outer races. An actuating cage is coupled to the wedge plate and is axially moveable relative to the wedge plate. Axial movement of the actuating cage causes radial expansion and contraction of the wedge segments to selectively transfer torque between the inner race and the outer race.
In another embodiment, a wedge clutch includes a hub extending along an axis, and a wedge plate having a plurality of wedge plate segments concentric with the hub and disposed radially outward of the hub. The wedge plate segments each have an outer surface. A carrier is concentric with the hub, extends along the axis, and is disposed radially outward of the wedge plate. The carrier has an inner surface facing the outer surfaces of the wedge plate segments. An actuating cage has a plurality of projections, each projection extending between two of the wedge plate segments. Axial movement of the actuating cage along the axis relative to the wedge plate selectively locks and unlocks the wedge clutch.
In yet another embodiment, a wedge clutch includes an inner race, an outer race, and a wedge plate located radially between the inner race and the outer race. An actuating cage has a plurality of projections extending through the wedge plate. Axial movement of the actuating cage causes radial expansion and contraction of the actuating cage to selectively engage and disengage the outer race and the inner race.
Embodiments of the present disclosure are described herein. It is to be understood, however, that the disclosed embodiments are merely examples and other embodiments can take various and alternative forms. The figures are not necessarily to scale; some features could be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the embodiments. As those of ordinary skill in the art will understand, various features illustrated and described with reference to any one of the figures can be combined with features illustrated in one or more other figures to produce embodiments that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. Various combinations and modifications of the features consistent with the teachings of this disclosure, however, could be desired for particular applications or implementations.
In the example shown in
An outer edge 60 of the wedge plate 42 is disposed in a groove 58 of the carrier 40, and an inner edge 61 of the wedge plate is disposed on the hub 38. When the wedge clutch 36 is locked, the outer edge 60 frictionally engages with the groove 58, and the inner edge 61 engages with the hub 38 (which is a ramped surface in this example) to couple the carrier 40 to the hub 38, creating a power flow path between the input shaft 26 and the output shaft 32.
The wedge plate may include a plurality of wedge segments retained together by springs and biased to the disengaged position. For example,
The use of retaining springs and snap rings increases costs of manufacture and assembly. It is therefore desirable to have a wedge clutch with radially-expanding wedge segments while reducing production costs, assembly costs, and weight.
Therefore, according to various embodiments of this disclosure, a wedge clutch is provided with an actuating cage that moves relative to the wedge segments to radially displace the wedge segments. The actuating clutch may hold or bind the wedge segments together, or may not hold the wedge segments together. As will be described below, the actuating cage can move axially to thereby radially displace the wedge segments to engage and disengage the wedge clutch.
One example of such a wedge clutch is shown in
In the disengaged state shown in
The wedge clutch 100 also includes an actuating cage 120. The actuating cage 120 is able to translate linearly along the axis 112, as shown in
As can be seen in
In one embodiment, the projections 124 have eight sides. The two largest of the sides are in contacting engagement with the radially-inward portion of the cut-outs 130. The next two largest of the sides are in contacting engagement with the radially-outward portion of the cut-outs 130. The remaining sides do not contact the cut-outs directly, but remain substantially separated from the cut-out surfaces to facilitate relative movement between the projections 124 and the plate 122.
As can be seen in
It should be understood that the actuating cage 120 shown in the figures is merely one embodiment. Other designs can be utilized while still maintaining the function of sliding relative to the wedge plate segments to expand or contract them. For example, in one embodiment, the projections of the actuating cage extend radially outward, such that the radial inward and outward movement of the wedge segments is reversed relative to the directional movement of the actuating cage shown in
While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes can be made without departing from the spirit and scope of the disclosure. As previously described, the features of various embodiments can be combined to form further embodiments of the invention that may not be explicitly described or illustrated. While various embodiments could have been described as providing advantages or being preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, those of ordinary skill in the art recognize that one or more features or characteristics can be compromised to achieve desired overall system attributes, which depend on the specific application and implementation. These attributes can include, but are not limited to cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. As such, to the extent any embodiments are described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics, these embodiments are not outside the scope of the disclosure and can be desirable for particular applications.
