Provided, in one aspect, is a downhole torque limiter, comprising a tubular housing; a pipe positioned within the tubular housing, the pipe transitioning from a larger inside diameter (ID.sub.L) to a smaller inside diameter (ID.sub.S), thereby forming a venturi profile having a first pressure zone (Z.sub.1) and a second pressure zone (Z.sub.2); a tubular valve plate radially positioned between the tubular housing and the pipe and rotationally fixed with the pipe; a lower sub rotationally fixed relative to the tubular housing and rotationally coupled to the tubular valve plate via a clutch mechanism; and a valve assembly positioned within a longitudinal opening extending along at least a portion of a sidewall of the tubular valve plate, the valve assembly configured to be activated by a pressure drop created by fluid flowing through the venturi profile.

A clutch (1) includes a housing (3) connected to a drive input member (5). First friction discs (7) are mounted in the housing and rotate therewith. Second friction discs (9) are mounted on a driven member (11). A pressure plate (13) is elastically stressed toward the driven member to compress the first and the second friction discs (7, 9) against one another. Cam profiles (31, 33) integral with the driven member and with the pressure plate, generate a thrust to move the driven member and pressure plate away from each other when it is necessary to reduce the pressure exerted by the pressure plate on the first and second friction discs. An angular stroke limiter limits the relative rotation between the driven member and the pressure plate and thereby limits the movement of the pressure plate away from the driven member).

A clutch (1) includes a housing (3) connected to a drive input member (5). First friction discs (7) are mounted in the housing and rotate therewith. Second friction discs (9) are mounted on a driven member (11). A pressure plate (13) is elastically stressed toward the driven member to compress the first and the second friction discs (7, 9) against one another. Cam profiles (31, 33) integral with the driven member and with the pressure plate, generate a thrust to move the driven member and pressure plate away from each other when it is necessary to reduce the pressure exerted by the pressure plate on the first and second friction discs. An angular stroke limiter limits the relative rotation between the driven member and the pressure plate and thereby limits the movement of the pressure plate away from the driven member).

The invention relates to a coupling device for a drive train of a motorcycle or other motor vehicle, in particular for suppressing a so-called hopping. According to the invention, the coupling device has an output rotation part, a switchable friction coupling, which has an energy storage device for closing thereof and which is closed in an unactuated state, and at least one freewheel coupling for forming a torque transmission path for torque transmission from the input rotating part to the output rotating part, wherein the freewheel coupling includes the following components: an inner rotating element, the outer circumference of which forms a sawtooth-shaped circumferential structure having a plurality of circumferentially extending ramps; a substantially annular plate structure having an individual plate element or a stack of a plurality of plate elements, the inner circumference of which forms a sawtooth-shaped circumferential structure having a plurality of circumferentially extending counter-ramps to form an interlock and/or a friction lock together with the ramps of the inner rotating element in a rotation direction; and an outer rotating element surrounding the plate structure. The invention further relates to a corresponding drive train having such a coupling device.

The invention relates to a coupling device for a drive train of a motorcycle or other motor vehicle, in particular for suppressing a so-called hopping. According to the invention, the coupling device has an output rotation part, a switchable friction coupling, which has an energy storage device for closing thereof and which is closed in an unactuated state, and at least one freewheel coupling for forming a torque transmission path for torque transmission from the input rotating part to the output rotating part, wherein the freewheel coupling includes the following components: an inner rotating element, the outer circumference of which forms a sawtooth-shaped circumferential structure having a plurality of circumferentially extending ramps; a substantially annular plate structure having an individual plate element or a stack of a plurality of plate elements, the inner circumference of which forms a sawtooth-shaped circumferential structure having a plurality of circumferentially extending counter-ramps to form an interlock and/or a friction lock together with the ramps of the inner rotating element in a rotation direction; and an outer rotating element surrounding the plate structure. The invention further relates to a corresponding drive train having such a coupling device.

A dual clutch device having an input side, a first output side, and a second output side, which are arranged rotatably about an axis of rotation, and having a first, radially outer friction clutch for producing frictional engagement between the input side and the first output side and a second, radially inner friction clutch for producing frictional engagement between the input side and the second output side. Each friction clutch has a first friction element, which engages in the input side in a torque-transmitting manner, a second friction element, which engages in the associated output side in a torque-transmitting manner, a control element for providing an axially pressing force on the friction elements, and a leaf spring element, which is spirally wound around the axis of rotation and which is arranged axially between the control element and the friction elements.

A friction surface clutch having two conical friction surface pairs each with an inner friction surface element and an outer friction surface element, wherein the inner friction surface element is mounted axially displaceable with respect to a rotational axis, and wherein a frictionally locking connection is set up and canceled in a manner which is dependent on the axial displacement position of the inner friction surface element. The inner friction surface element is coupled to a separate transmission element such that the inner friction surface element and the transmission element can be rotated jointly about the rotational axis, with the coupling being set up via a bearing contact between a guide surface on the inner friction surface element and a countersurface on the transmission element.

A friction surface clutch having two conical friction surface pairs each with an inner friction surface element and an outer friction surface element, wherein the inner friction surface element is mounted axially displaceable with respect to a rotational axis, and wherein a frictionally locking connection is set up and canceled in a manner which is dependent on the axial displacement position of the inner friction surface element. The inner friction surface element is coupled to a separate transmission element such that the inner friction surface element and the transmission element can be rotated jointly about the rotational axis, with the coupling being set up via a bearing contact between a guide surface on the inner friction surface element and a countersurface on the transmission element.

A downhole torque limiter. The downhole torque limiter may include a tubular housing; a pipe positioned within the tubular housing, the pipe transitioning from a larger inside diameter (ID.sub.L) to a smaller inside diameter (ID.sub.S), thereby forming a venturi profile having a first pressure zone (Z.sub.1) and a second pressure zone (Z.sub.2); a tubular valve plate radially positioned between the tubular housing and the pipe and rotationally fixed with the pipe; a lower sub rotationally fixed relative to the tubular housing and rotationally coupled to the tubular valve plate via a clutch mechanism; and a valve assembly positioned within a longitudinal opening extending along at least a portion of a sidewall of the tubular valve plate, the valve assembly configured to be activated by a pressure drop created by fluid flowing through the venturi profile.

A downhole torque limiter. The downhole torque limiter may include a tubular housing; a pipe positioned within the tubular housing, the pipe transitioning from a larger inside diameter (ID.sub.L) to a smaller inside diameter (ID.sub.S), thereby forming a venturi profile having a first pressure zone (Z.sub.1) and a second pressure zone (Z.sub.2); a tubular valve plate radially positioned between the tubular housing and the pipe and rotationally fixed with the pipe; a lower sub rotationally fixed relative to the tubular housing and rotationally coupled to the tubular valve plate via a clutch mechanism; and a valve assembly positioned within a longitudinal opening extending along at least a portion of a sidewall of the tubular valve plate, the valve assembly configured to be activated by a pressure drop created by fluid flowing through the venturi profile.