Clutch actuator

A clutch actuator includes: a reduction gear to rotate in a housing by a motor; a connecting rod having a first end connected to the reduction gear; a pair of levers provided on a hinge shaft in the housing, and connected to a second end of the connecting rod to rotate according to a rotation of the reduction gear; a push rod contacting with a clutch actuator fork; and a wear compensating unit movably coupled between the levers in a vertical direction and provided with an inclined surface contacting a first cam. In particular, the push rod has one end extended outwardly of the housing and is coupled with the first cam of which one end is movably inserted into the first hole of the levers.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority to and the benefit of Korean Patent Application No. 10-2016-0171214, filed on Dec. 15, 2016, the entire contents of which is incorporated herein by reference.

FIELD

The present disclosure relates to a clutch actuator for a clutch.

BACKGROUND

Generally, a manual transmission transmits a force through a tappet of a clutch release cylinder by an oil pressure generated from a clutch master cylinder when a driver steps on a clutch pedal and transmits a force to a clutch diaphragm spring by allowing the force transmitted through the tappet to push a clutch release fork to thereby move a release bearing in an axial direction.

The clutch is disposed between an engine and the transmission and is connected between an engine side flywheel and a transmission input shaft to transmit or block a torque of the engine to the transmission.

By the way, in the case of the clutch pedal and the hydraulic cylinder, it is troublesome for a driver to directly operate the clutch pedal, and the driving feeling and the driving safety are greatly influenced by the skill of the driver. Therefore, recently, an automated manual transmission and a double clutch transmission tend to be used.

A clutch actuator carries out a clutch interruption operation of the automated manual transmission and the double clutch transmission. One example of the clutch actuator is disclosed in a related art.

As a means for interrupting power at the time of shifting during the transfer of the power of the engine to wheels through the transmission, the clutch is configured to transmit power by a frictional force. The frictional force is generated from disks provided to face each other on one side of a flywheel provided on a crank shaft of the engine and on one side of an input shaft of the transmission.

A clutch disc of the clutch is provided with a friction material for generating a frictional force and is severely worn due to the repeated interruption operation of the clutch. We have discovered that the disk wear causes a problem that the clutch operated by the clutch actuator is incompletely operated.

The matters described as the related art have been provided only for assisting in the understanding for the background of the present disclosure and should not be considered as corresponding to the related art known to those skilled in the art.

SUMMARY

The present disclosure proposes a clutch actuator capable of keeping a stroke control position of the actuator the same by compensating for a movement of a push rod using a wear compensating unit in a clutch housing, when a clutching facing wear occurs.

In one form of the present disclosure, a clutch actuator includes: a reduction gear configured to rotate in the housing by a torque of a motor; a connecting rod having a first end connected to the reduction gear; a pair of levers configured to be provided on a hinge shaft in the housing, connected to a second end of the connecting rod, to rotate according to a rotation of the reduction gear, and have a first hole in a horizontal direction provided in an upper portion of the pair levers with respect to the hinge shaft; a push rod configured to be in contact with clutch actuator fork, having a first end extended outwardly of the housing, be coupled with a first cam of which one end is movably inserted into the first hole to operate the clutch actuator fork while linearly moving according to the rotation of the at least one lever of the pair of levers; and a wear compensating unit configured to be movably coupled between the pair of levers in a vertical direction and provided with an inclined surface contacting the first cam to adjust a position of the first cam while vertically moving based on a degree of a clutch facing wear.

The pair of levers may be provided with a second hole and a third hole in a horizontal direction that are provided in a lower portion of the pair of levers with respect to the hinge shaft, and a second cam and a third cam may be inserted into the second hole and the third hole, respectively.

The wear compensating unit may include: a first plate having a first inclined surface configured to contact the first cam provided at an upper end of the first plate, and a second inclined surface configured to contact the second cam provided at a lower end of the first plate to be moved downwardly when the first cam is moved in one direction so as to move the second cam in another direction; and a second plate having a third inclined surface configured to contact the second cam provided with a lower end portion of the second plate, and a fourth inclined surface configured to contact the third cam provided at an upper end portion of the second plate to be moved upwardly when the second cam is moved in the another direction to thereby move the third cam in the another direction.

The second end of the connecting rod may be coupled to the third cam.

The first inclined surface may be formed in a direction in which the first plate is moved downward when the first cam is moved in the one direction and the second inclined surface may be formed in a direction in which the second cam is moved in the another direction when the first plate is moved downward, and the third inclined surface and the fourth inclined surface may be formed in a direction opposite to a direction in which the second inclined surface is headed.

A plurality of rivets may be formed between the pair of levers, and a plurality of vertical long holes may be formed at corresponding positions to the plurality of rivets so that the rivets are inserted into the wear compensating unit.

The push rod may have a middle portion protrudedly provided with a protrusion and a second end inserted into a pivot, and a compression spring may be provided between the protrusion and the pivot of the push rod.

One end of the pivot may be provided with a groove into which the first cam is inserted, and thus the pivot and the push rod may be integrally formed with respect to the first cam.

An auxiliary spring may be connected between the lower end of the pair of levers and the housing.

The clutch actuator may further include: an absorption spring having a first end fixed in the housing and a second end configured to contact a stopper protruding on one side of the reduction gear to reduce or prevent a backlash of the reduction gear.

DETAILED DESCRIPTION

FIG. 1is a cross-sectional view of a clutch actuator,FIG. 2is a cross-sectional view illustrating an operation of the clutch actuator upon engagement of the clutch, andFIG. 3is a cross-sectional view illustrating the operation of the clutch actuator upon a clutch wear.

Referring first toFIG. 1, a clutch actuator in one form of the present disclosure includes: a reduction gear20configured to rotate in a housing5by a torque of a motor10; a connecting rod25having one end connected to the reduction gear20; a pair of levers30configured to be provided on a hinge shaft40in the housing5, connected to the other end of the connecting rod25to rotate according to a rotation of the reduction gear20, and have a first hole31in a horizontal direction provided in an upper portion thereof with respect to the hinge shaft40. The clutch actuator further includes a push rod50that is in contact with an actuator fork100while extending outwardly of the housing5, coupled with a first cam32of which the other end is movably inserted into the first hole31to operate the clutch actuator fork100while linearly moving according to the rotation of the lever30. The clutch actuator further includes a wear compensating unit60which is movably coupled between the levers30in a vertical direction and provided with an inclined surface contacting the first cam32to adjust a position of the first cam32while vertically moving depending a degree of a clutch facing wear. The motor10may rotate based on a control signal of a transmission control unit (TCU). A gear applied to a shaft of the motor10is engaged with the reduction gear20and thus the reduction gear20is supplied with a torque of the motor10.

As illustrated inFIG. 2, if the reduction gear20rotates, a torque is transmitted to the lever30through the connecting rod25, and the push rod50is pushed forward by the rotation of the lever30to push one end of the clutch actuator fork100. The other end of the clutch actuator fork100is fixed by a fulcrum105to push forward a release bearing110contacting a middle portion of the clutch actuator fork, and a pressure plate130is released from a clutch disk140while a diaphragm spring120connected thereto is bent. Here, a point at which the lever30rotates to contact the housing5is designated as a control reference point.

Meanwhile, the wear compensating unit60is inserted between the pair of levers30. In one form, as illustrated inFIG. 3, when the clutch disc140is worn and thus the first cam32pushed backward along the first hole31by the push rod50, the wear compensating unit60switches the backward pushing to a vertical direction to inhibit or prevent a distance of the control reference point of the lever30and the housing5from being changed, thereby inhibiting or preventing a touch point from being changed. Therefore, the stroke control of the clutch actuator may be accurately performed even if the clutch face wear occurs.

FIG. 4is a front view illustrating a lever and a wear compensating unit as one form of the present disclosure, andFIG. 5is a front view illustrating an operation of the wear compensating unit. Referring toFIGS. 4 and 5, the levers30are provided with a second hole33and a third hole35in a horizontal direction that are provided in a lower portion of the lever30with respect to the hinge shaft40, and a second cam34and a third cam36are inserted into the second hole33and the third hole35, respectively.

Further, the wear compensating unit60may include a first plate61configured to have an inclined surface62contacting the first cam32provided at an upper end of first plate61and a second inclined surface63contacting the second cam34provided at a lower end of the first plate61to be moved downwardly when the first cam32is moved in one direction to thereby move the second cam34in the other direction. A second plate65has a third inclined surface67contacting the second cam34provided with a lower end portion of the second plate65and a fourth inclined surface67contacting the third cam36provided at an upper end portion of the second plate65to be moved upwardly when the second cam34is moved in the other direction to thereby move the third cam36in the other direction.

At this point, the other end of the connecting rod25is provided to be coupled to the third cam36.

Further, the first inclined surface62is formed in a direction in which the first plate61is moved downward when the first cam32is moved in one direction and the second inclined surface63is formed in a direction in which the second cam34is moved in the other direction when the first plate61is moved downward and the third inclined surface66and the fourth inclined surface67may be formed in a direction opposite to the direction in which the second inclined surface63is headed.

As illustrated inFIG. 4, before the clutch facing wear occurs, the first cam32coupled with the other end of the push rod is positioned at one side of the first hole31and the second cam34and the third cam36are positioned at the other side of the second hole33and the third hole35, respectively. This is because the reduction gear20is fixed and thus the third cam36is fixed to the other side of the third hole35. As a result, the second plate65is kept moved downward and the first plate61is kept moved upward, by the fixed force transmitted to the second cam34and the first cam32.

If the clutch facing wear occurs, the push rod50is pushed backward as illustrated inFIG. 3, and thus the first cam32is moved to the other side along the first hole31as illustrated inFIG. 5. The first plate61is moved downward by the first inclined plane62contacting with the first cam32and the second cam34is moved to the other side along the second hole33by the second inclined plane63. Therefore, the second plate65is moved upward by the third inclined surface66and the fourth cam36contacting the fourth inclined surface67is moved to the other side to push the connecting rod25forward.

Therefore, even if a back stroke occurs in the clutch actuator fork due to the clutch facing wear, the control stroke distance between the lever30and the housing5is not changed, such that the accurate clutch actuator control may be performed.

A plurality of rivets70are formed between the levers30and a plurality of vertical long holes may be formed at corresponding positions so that the rivets70are inserted into the wear compensating unit60.

Therefore, the first and second plates61and65may be vertically moved between the levers30but may be inhibited or prevented from moving to other positions.

Meanwhile,FIG. 6is a view illustrating in detail the push rod in one form of the present disclosure. Referring toFIG. 6, the push rod50has a middle portion provided with a protrusion53and the other end inserted into a pivot55, in which a compression spring57is provided between the protrusion53and the pivot55of the push rod50. That is, it is possible to inhibit or prevent the push rod50from being pushed backward by simple shaking.

Further, the other end of the pivot55is provided with a groove59into which the first cam32is inserted, and thus the pivot55and the push rod50may be integrally formed with respect to the first cam32. Therefore, the push rod50may be provided to be linearly moved even if the lever30rotates.

FIG. 7is a view illustrating the operation of the clutch actuator upon the engagement of the clutch wear in one form of the present disclosure, andFIG. 8is a view illustrating the operation of the clutch actuator upon disengagement of the clutch wear.

Referring toFIGS. 7 and 8, an auxiliary spring80may be connected between the lower end of the lever30and the housing5. That is, the auxiliary spring80is provided to apply a force to restore the lever30to a state in which the clutch is released, thereby reducing a load of the motor.

Further, the clutch actuator may further include an absorption spring configured to have one end fixed in the housing5and the other end provided to contact a stopper27protruding on one side of the reduction gear20to reduce or prevent a backlash of the reduction gear20.

FIG. 9is a perspective view illustrating a reduction gear in one form of the present disclosure. Referring toFIGS. 7 to 9, one end of the absorption spring90is kept fixed in the housing5, and when a back stroke force is transmitted to the reduction gear20, the absorption spring90abuts to the stopper27of the reduction gear20, thereby absorbing the backlash force of the reduction gear20.

In addition, a boot inserted into the push rod50may be provided outside the housing5to reduce or prevent foreign matters from penetrating into the clutch housing and to provide water tightness with the push rod50.

The clutch actuator having the above-mentioned structure may keep the control stroke position of the actuator the same even if the clutch facing wear occurs, thereby improving the accuracy of the stroke control.

Although the present disclosure has been illustrated and described with respect to specific exemplary forms, it will be obvious to those skilled in the art that the present disclosure may be variously modified and altered without departing from the spirit and scope of the present disclosure.