Clutch actuating apparatus for double clutch transmission

A clutch actuating apparatus for a double clutch transmission, may include an operation rod that constructs an operation stroke for engaging a clutch while moving straight, an electric power unit that generates a rotational force, a straight converting unit that converts the rotational force of the electric power unit into a straight movement force for moving straight the operation rod, a supplement force supplying unit for increasing the straight movement force of the operation rod and removing increased straight movement force in accordance with whether the operation rod engages or disengages the clutch, a rod locating unit that changes a position of the operation rod relative to the straight converting unit, and a housing that accommodates the straight converting unit and the supplement force supplying unit and covers the operation rod with a portion exposed to the outside.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to Korean Patent Application Number 10-2010-117155 filed Nov. 23, 2010, the entire contents of which application is incorporated herein for all purposes by this reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a clutch actuating apparatus for a double clutch transmission, and more particularly, to a technology about an actuator that respectively engages/disengages two clutches of a double clutch transmission.

2. Description of Related Art

Double clutch transmissions, different from a single clutch transmission systems of the related art, are shifting systems equipped with two clutches and designed to form separate shifting lines while one clutch connects/disconnects the gears of the odd-numbered stages and the other clutch connects/disconnects the gears of the even-numbered stages, which facilitate driving, such as automatic transmission, and achieve larger improvement of fuel efficiency than manual transmissions.

Further, double clutch transmissions allow for smooth shifting, because disconnection of acceleration, chattering and difference when gears are engaged, which are generated in transmissions equipped with a single clutch, do not occur.

The double clutch transmissions are provided with a pre-select function that engages in advance a shift gear of a shift stage in a next desired shift line other than the present shift stage, and directly shift only by changing the operation of the two clutches.

That is, with shift stages of two different shift lines engaged, respectively, the transmission ratio outputted from the transmission is changed in accordance with which clutch of the two clutches is engaged.

As described above, a clutch actuating apparatus for engaging a clutch should engage a clutch while being mechanically moved by electric operation or hydraulic operation, such that sufficient force for engaging the clutch should be applied to an apply bearing and a function of compensating frictional wear is required to compensate increase of the operational stroke when the clutch is worn.

Further, the clutch actuating apparatus requires a self-opening function that allows the clutch to be automatically disengaged in order to ensure safety in an emergency, such as when power of a vehicle is cut, and is usually attached to the outer side of a transmission case; therefore, it is required to be mounted in a small size in order not to protrude a lot out of the transmission case or occupy a large volume.

BRIEF SUMMARY

Various aspects of the present invention are directed to provides a clutch actuating apparatus for a double clutch transmission that can engage a clutch with an electric power unit having a relatively small capacity, supply sufficient force for engaging the clutch to an apply bearing, provide an abrasion compensation function that allows the clutch to always stably and appropriately operate by automatically compensating the operation stroke when the clutch is worn, and a self-opening function that automatically disengages the clutch when power supplied to the electric power unit is cut.

Further, various aspects of the present invention are directed to provides a clutch actuating apparatus for a double clutch transmission that is configured to use common clutch mechanism provided with a separate clutch lever as it is, in order to implement clutch mechanism of a double clutch transmission using various parts and general technologies that have been developed in the related art, and has a simple and compact configuration to be easily mounted in a vehicle.

In an aspect of the present invention, the clutch actuating apparatus for a double clutch transmission, may include an operation rod that constructs an operation stroke for engaging a clutch while moving straight, an electric power unit that generates a rotational force, a straight converting unit that converts the rotational force of the electric power unit into a straight movement force for moving straight the operation rod, a supplement force supplying unit for increasing the straight movement force of the operation rod and removing increased straight movement force in accordance with whether the operation rod engages or disengages the clutch, a rod locating unit that changes a position of the operation rod relative to the straight converting unit, and a housing that accommodates the straight converting unit and the supplement force supplying unit and covers the operation rod with a portion exposed to the outside.

The electric power unit may include an electric motor, the straight converting unit may include a screw rotated by the electric motor, a nut block thread-coupled to the screw to move straight along the screw, and a nut guide formed to the housing and being slidably coupled to the nut block to guide the nut block to move straight by preventing rotation of the nut block, and the electric motor may be connected to be controlled by a controller that receives an output shaft velocity information of the double clutch transmission.

The rod locating unit may include a rod block slidably assembled to the housing so as to move straight with respect to the housing by receiving a straight movement force of the nut block, wherein the operation rod may be slidably coupled to the rod block and guides the operation rod to move straight and wherein the rod block may be coupled to the nut block, a pinion gear that may be rotatably mounted in the rod block to move straight the operation rod with respect to the rod block while rotating, a one-way clutch that may be rotatably mounted in the rod block to allow the pinion gear to rotate in a direction without reversing, and a clutch rotating unit that rotates the pinion gear by a predetermined angle in the direction allowed by the one-way clutch, when the rod block moves straight in a compensation section across an origin in a disengagement direction of the clutch.

The clutch rotating unit may include a latch gear that may be coaxially coupled to the pinion gear to rotate the pinion gear and may have a plurality of locking teeth, and a locking lever that may be mounted in the housing to rotate the latch gear by a predetermined amount, by being locked to the locking teeth by the rod block at regular intervals on an outer circumference thereof, when the rod block moves in the disengagement direction of the clutch, and wherein the controller controls the electric motor such that the rod block moves straight in the compensation section.

The one-way clutch may include a driving-sided dog coaxially fitted on a rotary shaft of the pinion gear by a spline, a fixing-sided dog disposed between the driving-sided dog and the pinion gear to be restricted in rotation by the rod block and allowed to move straight along the rotary shaft of the pinion gear, a return spring elastically supporting the fixing-sided dog against the driving-sided dog, and a plurality of wedged protrusions formed at regular intervals on surfaces facing each other of the fixing-sided dog and the driving-sided dog and engaged with each other to allow for one-directional rotation with respect to each other.

The one-way clutch may be disposed at one side of the pinion gear, the latch gear may be disposed at the other side of the pinion gear, a bias elastic member may be disposed between the locking lever and the housing to elastically support the locking lever against the latch gear, and an idler gear rotatably mounted to the rod block may be engaged with the pinion gear and transmits rotational force of the pinion gear to the operation rod for moving the operation rod straight.

The clutch actuating apparatus for the double clutch transmission may further include a carrier slidably coupled to the rod block and having a rack engaged with the idler gear on an outer surface thereof, wherein the operation rod may be coupled to the carrier.

The supplement force supplying unit may include a pressing slope that protrudes from a straight plane of the rod block, which may be parallel with a straight movement direction of the rod block, at an angle with respect to the straight movement direction, a pressing roller that continuously contacts with the straight plane or the pressing slope while the rod block moves straight, and a pressing elastic member disposed perpendicular to the straight plane of the rod block and applying an elastic force to the pressing roller.

The electric motor may be disposed opposite to a protrusion direction of the operation rod in the housing, and the electric motor, the straight converting unit, the rod block, and the supplement force supplying unit may be disposed on the same plane.

The rod block may have block extenders at both sides from the center of the rod block in a longitudinal direction of the operation rod, a plurality of rollers may be disposed between the block extenders and an inner wall of the housing to guide the block extender to move straight, the pressing slope of the supplement force supplying unit may be formed between the straight plane and the block extender formed in the protrusion direction of the operation rod in the block extenders, and a fixing protrusion that may be inserted and fixed in the nut block integrally protrudes from the rod block between the block extenders.

The controller monitors the timing of change in an output shaft velocity of the double clutch transmission and when an expected change in the output shaft velocity may be delayed over a predetermined level, the controller operates the rod locating unit.

The present invention can engage a clutch with an electric power unit having a relatively small capacity, supply sufficient force for engaging the clutch to an apply bearing, provide an abrasion compensation function that allows the clutch to always stably and appropriately operate by automatically compensating the operation stroke when the clutch is worn, and a self-opening function that automatically disengages the clutch when power supplied to the electric power unit is cut.

Further, the present invention is configured to use a common clutch mechanism provided with a separate clutch lever as it is, in order to implement a clutch mechanism of a double clutch transmission using various parts and general technologies that have been developed in the related art, and has a simple and compact configuration to be easily mounted in a vehicle.

DETAILED DESCRIPTION

Referring toFIGS. 1 to 4, a clutch actuating apparatus according to an exemplary embodiment of the present invention includes, an operation rod1that constructs an operation stroke for engaging a clutch while moving straight, an electric power unit that generates rotational force, a straight converting unit3that converts the rotational force of the electric power unit into straight movement force for moving straight operation rod1, a supplement force supplying unit5that implements a state for increasing straight movement force of operation rod1and removing the increased straight movement force, in accordance with whether operation rod1engages/disengages the clutch, a rod locating unit7that changes the relative position of operation rod1to straight converting unit3, and a housing9that accommodates straight converting unit3and supplement force supplying unit5and covers operation rod1with a portion exposed to the outside.

The electric power unit may be an electric motor11. The straight converting unit3includes a screw13rotated by electric motor11, a nut block15thread-fastened to screw13to move straight, and a nut guide17guiding nut block15to move straight by preventing rotation of nut block15.

That is, as screw13is rotated by electric motor11, nut block15moves straight along the spiral on screw13and nut guide17is inserted in a straight groove formed on nut block15, such that nut block15is guided to move straight without rotating.

Electric motor11is connected to be controlled by a controller19, which receives the output shaft velocity information of a double clutch transmission, and a velocity sensor21that measures the output shaft velocity of the transmission is connected to controller19.

Rod locating unit7includes a rod block23that guides operation rod1to move straight and moves straight with respect to housing9by receiving straight movement force of nut block15, a pinion gear25mounted in rod block23to move straight operation rod1with respect to rod block23while rotating, a one-way clutch27mounted in rod block23to allow pinion gear25to rotate in one direction without reversing, and a clutch rotating unit29rotating pinion gear25by a predetermined angle in the direction allowed by one-way clutch27, when rod block23moves straight in a compensation section across the origin in the disengagement direction of the clutch.

The origin is the position where rod block23starts moving straight to engage the clutch, in which rod block23returns to the origin when the clutch is disengaged, and the compensation section implies a predetermined straight distance where rod block23moves straight from the origin in the disengagement direction of the clutch such that clutch rotating unit29operates.

Clutch rotating unit29includes a latch gear31that is coaxially coupled to pinion gear25to rotate pinion gear25and has a plurality of locking teeth at regular intervals on the outer circumference and a locking lever33that is mounted in housing9to rotate latch gear31by a predetermined amount, by being locked to the locking teeth, when rod block23moves in the compensation section in the disengagement direction of the clutch. Controller19can control electric motor11such that rod block23moves straight in the compensation section.

One-way clutch27includes a driving-sided dog35coaxially fitted on the rotary shaft of pinion gear25by a spline, a fixing-sided dog37disposed between driving-sided dog35and pinion gear25to be restricted in rotation by rod block and allowed to move straight along the rotary shaft of pinion gear25, and a return spring39elastically supporting fixing-sided dog37against driving-sided dog35, in which a plurality of wedged protrusions63is formed at regular intervals on the surfaces facing each other of fixing-sided dog37and driving-sided dog35and engaged with each other to allow for one-directional rotation with respect to each other.

One-way clutch27is disposed at one side of pinion gear25, latch gear31is disposed at the other side of pinion gear25, a bias elastic member41is disposed between locking lever33and housing9to elastically support locking lever33against latch gear31, and an idler gear43, which transmits power for moving operation rod1straight, using rotational force from pinion gear25, is engaged with pinion gear25.

That is, it is possible to implement a more stable and durable configuration by separately and symmetrically disposing one-way clutch27and latch gear31at both sides of pinion gear25and it is possible to dispose one-way clutch27and latch gear31closer to pinion gear25and achieve a more compact configuration by making it possible to output the rotational force of pinion gear25through idler gear43.

Operation rod1is integrally inserted and fixed in a carrier45and a rack47is formed on the surface of carrier45, such that rack47is engaged with idler gear43and accordingly the rotational force of pinion gear25is transmitted and operation rod1moves straight.

Therefore, when operation rod1is deformed or damaged by a long time use, a new operation rod1can be fixed in carrier45, such that maintenance becomes easy.

Supplement force supplying unit5includes: a pressing slope51that protrudes from a straight plane49of rod block23, which is parallel with the straight movement direction of rod block23, at an angle with respect to the straight movement direction, a pressing roller53that continuously contacts with straight plane49and pressing slope51while rod block23moves straight, and a pressing elastic member55that applies elastic force, which is perpendicular to straight plane49of rod block23, to pressing roller53.

That is, as rod block23moves straight to engage the clutch and pressing roller53moves to contact with pressing slope51from straight plane49of rod block23, the force applied from pressing roller53to rod block23is divided into the straight motion direction of rod block23by pressing slope51and added to the straight motion force of rod block23which is supplied from electric motor11. Therefore, the straight motion force of operation rod1is increased and pressing roller53contacts with straight plane49of rod block23while rod block23moves to disengage the clutch and returns to the origin, such that the divided force supplied from pressing roller53in the straight motion direction of rod block23is completely removed.

The operation of increasing the straight movement force of operation rod1when pressing roller53contacts with pressing slope51makes it possible to minimally use the electromotive force for electric motor11and maintain stable stop position of operation rod1while the clutch maintains the engagement, such that stable engagement of the clutch can be ensured.

The sum of the straight motion force of operation rod1which is supplied from electric motor11and straight movement force from supplement force supplying unit5keeps the clutch in stable engagement, however, when the force supplied from electric motor11is removed and only the force from supplement force supplying unit5is exerted, due to a failure of the power unit of a vehicle, the clutch is disengaged and power transmission is stopped in the vehicle, such that it is required to implement a self-opening function for ensuring stability of the vehicle. Therefore, the force applied to the clutch from supplement force supplying unit5through operation rod1should be set smaller than the elastic force exerted in the clutch such that the clutch is disengaged.

Obviously, the leads of screw13and nut block15should be sufficiently large such that screw13can be reversed by the straight movement force from nut block15, in order to implement the self-opening function.

Electric motor11is disposed opposite to the protrusion direction of operation rod1in housing9, and electric motor11, straight converting unit3, rod block23, and supplement force supplying unit5are disposed on one plane.

The arrangement described above makes more compact the clutch actuator apparatus for a double clutch transmission of the present invention, such that the clutch actuating apparatus can be more easily mounted to the transmission.

That is, according to the structures of common transmission, the size gradually decreases toward the rear from the front where the clutch housing is disposed, whereas operation rod1protrudes toward the clutch housing at the front of the transmission such that operation rod1is more easily connected to the clutch in the clutch housing while operation rod1having a relatively small volume faces the front of the transmission and electric motor11having a relatively large volume is positioned at the rear of the transmission in an exemplary embodiment of the present invention. Therefore, the clutch actuating apparatus of the present invention can be coupled to the transmission substantially in one unit without protruding a lot from the side of the transmission and the spatial limit for installing the transmission can be reduced.

Rod block23has block extenders57at both sides from the center in the longitudinal direction of operation rod1, a plurality of rollers59is disposed between block extenders57and the inner wall of housing9to guide block extender57to move straight, pressing slope51of supplement force supplying unit5is formed at the front end of block extender57in the protrusion direction of operation rod1in block extenders57, and a fixing protrusion61that is inserted and fixed in nut block15protrudes between block extenders57.

The operation of an exemplary embodiment having the above configuration according to an exemplary embodiment of the present invention is described hereafter.

Power is supplied to electric motor11such that screw13rotates, and nut block15is guided by nut guide17to move straight to the right inFIG. 1, in order that controller19engages the clutch.

The straight movement of nut block15is transmitted to rod block23and rod block23and operation rod1move to the right and operate the lever of the clutch connected to operation rod1, thereby engaging the clutch.

In this operation, as the amount of straight movement of rod block23increases, pressing roller53contacts with pressing slope51and provides the elastic force of pressing elastic member55in the straight movement direction of rod block23.

When the clutch is engaged, the engagement of the clutch is stably maintained by the force provided by pressing elastic member55while the electromotive force provided for electric motor11is minimally maintained. When the electricity that has been supplied to electric motor11is cut, the force applied to operation rod1correspondingly decreases and nut block15moves backward while rotating screw13by the reaction force applied to operation rod1from the inside of the clutch, and accordingly, the clutch is automatically disengaged and power transmission is stopped, such that it is possible to ensure safety of a vehicle when the power unit of the vehicle suddenly fails.

On the other hand, when it is required to normally disengage the clutch, as controller19reverses electric motor11, nut block15and rod block23move straight to the left and return to the origin, pressing roller53moves up along pressing slope51and contacts with straight plane49of rod block23, and operation rod1moves with rod block23, and consequently, the clutch is disengaged.

While the clutch is repeatedly engaged and disengaged as described above, the clutch is worn and the frictional wear should be appropriately compensated. Accordingly, controller19receives output shaft velocity information of the double clutch transmission from velocity sensor21and compensates the frictional wear of the clutch using rod locating unit7.

That is, controller19drives electric motor11to engage the clutch and then monitors the timing of change in the output shaft velocity of the double clutch transmission, in which when an expected change in the output shaft velocity is delayed over a predetermined level, controller17determines that the delay is due to frictional wear of the clutch, such that it operates rod locating unit7.

As controller19controls electric motor11and rod block23moves straight in the compensation section from the origin, the locking teeth of latch gear31are locked to locking lever33by the movement of rod block23, pinion gear25and driving-sided dog35of one-way clutch27are rotated by the rotation of latch gear31, and idler gear43engaged with pinion gear25moves rack47of carrier45while rotating, such that operation rod1is further moved straight to the right with respect to rod block23, thereby compensating abrasion of the clutch.

Obviously, driving-sided dog35can rotate because as driving-sided dog35is rotated by the inclination of wedged protrusions63, fixing-sided dog37axially moves straight while contracting return spring39.

As driving-sided dog35rotates, as described above, the rotational position is fixed in the reverse direction by the elastic force of return spring39and wedged protrusions63between driving-sided dog35and fixing-sided dog37, such that operation rod1can be stably kept at the position.

Obviously, when rod block23returns to the origin, which is the initial position, after moving along the compensation section, locking lever33is elastically supported against latch gear31such that it can be locked to the next locking tooth of latch gear31by bias elastic member41.