Patent Application
20180180110
The present disclosure relates to wedge clutches for coupling two or more rotatable elements.
A vehicle powertrain may include a wedge clutch for coupling an input shaft to an output shaft. The wedge clutch includes 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 clutch for selectively coupling first and second rotational members includes a hub rotatable about an axis and connectable to the first rotational member, and a carrier rotatable about the axis and connectable to the second rotational member. One of the hub and the carrier defines an annular groove and the other of the hub and the carrier defines a ramped surface. A wedge plate of the clutch has a first edge disposed on the ramped surface, a second edge disposed in the annular groove, and a face extending between the edges and defining an annular shoulder. An annular resilient member is seated against the shoulder.
According to another embodiment, a wedge clutch has first and second concentric races supported for rotation about a common axis. A wedge plate for the wedge clutch includes a plurality of arcuate segments arranged to form a disk. Each of the segments has an inner edge engageable with the first race, an outer edge engageable with the second race, and first and second opposing faces extending between the inner and outer edges. A retaining ring is adjacent to the first face on each of the arcuate segments to secure the segments as the disk. At least one clip is provided to secure the retaining ring to the disk. The clip includes a retaining portion disposed against the retaining ring and a clip portion connected to the disk.
According to yet another embodiment, a clutch includes a hub supported for rotation about an axis and a carrier supported for rotation about the axis. A wedge plate frictionally engages between the hub and the carrier when the clutch is locked to couple the hub and the carrier. The wedge plate includes a plurality of wedge segments arranged for rotation about the axis. A retaining ring interconnects the wedge segments to form a disk. A clip secures the retaining ring to the disk.
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.
Referring to
A wedge clutch 36 is disposed in the housing 22 and selectively couples the input shaft 26 to the output shaft 32 to transfer torque from the input shaft 26 to the output shaft 32. The clutch 36 has a closed state (also referred to as a locked state) in which the input and output shafts are coupled to each other and an open state (also referred to as an unlocked state) in which the input and output shafts are independently rotatable relative to each other. The wedge clutch 36 may include a hub 38 (which may be referred to as an inner race), a carrier 40, and a disk 42 (which may be referred to as a wedge plate) that are all supported for rotation about the axis 28.
The hub 38 includes an inner surface 46 connected to the output shaft 32 and an outer ramped surface 48. The ramped surface is inclined in the axial direction. The carrier 40 includes a base 50 connected to the input shaft 26, a radially extending portion 52, and an axially extending portion 54 (which may be referred to as an outer race). A projection 56 extends axially from the radially extending portion 52 and engages with the disk 42.
The disk 42 is radially disposed between the hub 38 and the axially extending portion 54. An inner edge 59 of the disk 42 defines a generally circular opening 62 that receives the hub 38 and is seated on the ramped surface 48. An outer edge 60 of the disk 42 is disposed in a groove 58 of the carrier 40. The groove may include opposing ramped surfaces 63. When the clutch 36 is locked, the outer edge 60 frictionally engages with the groove 58 and the inner edge 59 engages with the ramped surface 48 to couple the carrier 40 to the hub 38 creating a power flow path between the input shaft 26 and the output shaft 32.
An actuator 44 moves the clutch 36 between the open and closed states. The actuator 44 may be an electric actuator, as shown, or may be a hydraulic or mechanical actuator. In one embodiment, the electric actuator 44 includes electric coils 64 and an armature 66. The armature 66 is connected to the hub 38 and slides the hub towards the carrier 40 when energized to lock the clutch. A spring 67 may bias the hub 38 away from the carrier 40 to unlock the clutch when the armature 44 is de-energized. In some embodiments, the spring 67 is eliminated in lieu of a bidirectional actuator that also slides the hub 38 away from the carrier 40 to unlock the clutch.
The disk 42 may include multiple segments 72 (also known as wedge segments) retained together by an annular resilient member such as a retaining ring 74. The retaining ring 74 is formed of spring steel or other resilient material. Each of the segments 72 are annular and collectively form the disk 42 when assembled together. The retaining ring 74 may be secured to the disk 42 by clips 118.
The ramped surface 48 of the hub is not a perfect circle and includes cams 68 that ramp radially outward from the center of the hub. The cams 68 cooperate with the cams 70 on the inner edge 59 of the disk 42 to force the disk 42 radially outward to engage with the axially extending portion 54 when the clutch is locked. The segments 72 are moveable relative to each other allowing the disk to expand. Having multiple segments aids in the radial expansion of the disk. Multi-segment disks radially expand more uniformly than single-piece disks providing better engagement between the disk 42 and the carrier 40.
The clutch 36 is illustrated in the open state in
Referring to
Referring to
One or more clips 118 retain the retaining ring 74 to the disk 42. In the illustrated embodiment, the number of clips equals the number of arcuate segments 72 with one clip being attached to each of the segments 72. Each of the clips 118 includes an arcuate body 120 having an engaging side 124 disposed against the second face 112 of the retaining ring 74 and an exposed side 126. A pair of prongs 122 secures the body 120 to the arcuate segment 72. Each of the prongs 122 includes an elongated member 128 extending from the engaging side 124. A hooked end 130 is connected to a distal end of the elongate member 128. Each of the prongs 122 extends through one of the openings 94 allowing the body 120 to be disposed against a front side 132 of the segment 72 and the hooked end 130 to engage with the back side 134 of the segment. The outboard surface 80 may define one or more clips slots 136 that each receive one of the elongate members 128. The clip slots 136 are recessed into the base portion 76. The base portions 76 may include features on the back side 134 that the hooked end 130 snaps on to.
Referring to
Wedge clutches may be used in many different applications other than in a PTU. Wedge clutches may be used in any application that requires two or more rotating components to be selectively coupled together. Other possible uses include between a gear and a shaft and any other application in which two or more rotatable member are required to be selectively coupled.
This disclosure is not limited to the illustrated embodiments that show the outer race defining the groove and the inner race defining the ramped surface. In other embodiments, the placement of the hub and carrier are switched with the carrier being the inner race and the hub being the outer race. Here, the inner edge of the disk engages with a groove defined in the inner race, and the outer edge of the disk is disposed on the ramped surface of the outer race. Additional structure and operation of the wedge clutch is provided in the following documents, which are incorporated in their entirety by reference herein: U.S. patent application Ser. No. ______ (Attorney Docket SCHF0105PUS), filed on the same day as this disclosure; U.S. patent application Ser. No. ______ (Attorney Docket SCHF0106PUS), filed on the same day as this disclosure; U.S. patent application Ser. No. ______ (Attorney Docket SCHF0107PUS), filed on the same day as this disclosure; U.S. patent application Ser. No. ______ (Attorney Docket SCHF0108PUS), filed on the same day as this disclosure; and U.S. patent application Ser. No. ______ (Attorney Docket SCHF0109PUS), filed on the same day as this disclosure.
While example 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.
