192 clutches and power-stop control – Clutches – Automatic
Reexamination Certificate
2001-01-17
2002-05-14
Butler, Douglas C. (Department: 3613)
192 clutches and power-stop control
Clutches
Automatic
C192S043100, C192S069100, C192S046000, C192S045100, C188S082200
Reexamination Certificate
active
06386349
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to “one-way” clutches wherein the clutch is selectively disabled to permit “free-wheeling” of the driven member in either rotational direction relative to the driving member.
2. Background Information
Clutches are used in a wide variety of applications to selectively couple power from a first rotatable “driving” member, such as a driving disk or plate, to a second, independently-rotatable “driven” member, such as a driven plate or disk. In one known variety of clutches, commonly referred to as “one-way” or “overrunning” clutches, the clutch “engages” to mechanically couple the driving member to the driven member only when the driving member seeks to rotate in a first direction relative to the driven member. Once so engaged, the clutch will release or decouple the driven member from the driving member only when the driving member rotates in a second, opposite direction relative to the driven member. Further, the clutch otherwise permits the driving member to freely rotate in the second direction relative to the driven member. Such “free-wheeling” of the driving member in the second direction relative to the driven member is also known as the “overrunning” condition.
Occasionally, it is desirable to deploy a plurality of such one-way clutches along a common rotational axis in order to selectively drive a given output shaft in a selected rotational direction notwithstanding continuous rotation of an input shaft in a single rotational direction. For example, in a known embodiment, a driving member is disposed about a common rotational axis between a pair of driven members, with the driving member being axially translated relative to one or the other of the driven members to thereby permit exclusive torque transmission between the driving member and a selected one of the driven members using a one-way clutch. Because each driven member includes a plurality of circumferentially-spaced gear teeth to define a respective bevel gear, and because each bevel gear simultaneous meshes with a common pinion, the pinion is caused to be driven in opposite directions depending upon which driven member is mechanically coupled for rotation with the driving member. In this manner, an output shaft coupled to the pinion is selectively driven in either direction based upon the selected axial position of the driving member. A “neutral” position is advantageously provided by axially translation of the driving member to a position intermediate the two driven members, whereby rotation of the driving member does not produce any rotary output. Unfortunately, the need to axially translate the driving member relative to the driven members (or, indeed, each of several coaxial clutch assemblies deployed along a common drive shaft) and the resultant actuating structures implicates greater levels of mechanical complexity and increases the overall size of each such clutch assembly.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a clutch assembly with which to selectively couple an input shaft to an output shaft to thereby generate a rotary output in a selected rotational direction, which overcomes the deficiencies of the prior art.
Under the invention, a clutch assembly includes a driving member that is selectively and controllably rotatable about a first axis in each of two opposite rotational directions, for example, by an electric motor in accordance with a preferred method described further below. The driving member includes a first driving face that preferably defines a first reference surface that is generally perpendicular to the first axis. In a preferred embodiment, the driving member further includes a second driving face on the opposite side of the driving member that likewise preferably defines a second reference surface that is generally perpendicular to the first axis. The driving faces of the driving member each include at least one recess, with each recess defining a load-bearing shoulder that is operative when the driving member is rotated in the first direction, and with each recess preferably being adapted to receive a strut in the manner described further below. Significantly, each recess defined on the first driving face of the first driving is angularly offset from, i.e., is not axially aligned with, any recess defined on the driving member's second driving face.
The clutch assembly of the invention also includes a first driven member, also rotatable about the first axis, that includes a driven face in close-spaced opposition with the first driving face of the driving member and, hence, in the preferred embodiment, likewise defines a respective reference surface that is generally perpendicular to the first axis. The driven face of the first driven member includes a plurality of recesses, with each recess defining a respective load-bearing shoulder. A first coupling is disposed between the first driving face of the driving member and the driven face of the first driven member. The first coupling includes a first strut that, in a preferred embodiment, is carried by the driving member so as to rotate with the driving member. The first strut is moveable between a first position characterized by simultaneous abutting engagement of a respective end of the first strut with a respective shoulder of both the first driving face of the driving member and the driven face of the first driven member, and a second position characterized by non-engagement of the first strut with at least one of the first driving face of the driving member and the driven face of the first driven member (in the preferred embodiment, wherein the first strut is carried by the driving member within the recess defined in the driving member's first driving face, the second position is characterized by the nonengagement of the first strut with the driven face of the first driven member).
The first coupling also includes a first spring, for example, carried by the driving member, that urges the first strut toward the first position; and a first strut retainer rotatable about the first axis that operates to urge the first strut to the second position when the first strut retainer is rotated into a first predetermined rotational position relative to the driving member. By controlling the rotational position of the first strut retainer relative to the driving member, the first strut retainer is used to selectively enable or disable the nominal operation of the one-way planar clutch that is otherwise defined by the opposed members and the first coupling's spring-biased strut.
Critically, under the invention, the first strut retainer is rotatable about the first axis so as to rotate with the driving member only when the driving member is rotated in the first rotational direction relative to the first driven member, and, further, to rotate with the first driven member only when the driving member rotates in the second rotational direction relative to the first driven member. In this manner, the first strut is urged by the first strut retainer into the second, non-engaging position by controllably rotating the driving member in the second rotational direction into the first predetermined rotational position, whereupon the first one-way clutch defined by the driving member, the first driven member, and elements of the first coupling is disabled, with the driving member thereafter being free to “free-wheel” in the first rotational direction. It will be appreciated that, upon subsequent further rotation of the driving member in the second rotational direction relative to the driven member, the first strut retainer will rotate with the driving member out of the first predetermined rotational position, whereupon the thus-defined first one-way clutch is enabled to transmit power from the driving member to the first driven member upon subsequent relative rotation of the driving member in the first rotational direction and to “free-wheel” when the first driven member overruns the driving member while rotating in the first rotational dir
Brooks & Kushman P.C.
Butler Douglas C.
Means Industries Inc.
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