1. Field of the Invention
The present invention relates to a clutch driving device, particularly a clutch driving device that operates a clutch in a horizontal motion and vertical translation method, by generating lever-sided vertical translation via a move distance of rollers horizontally moving to both sides and converting the vertical translation into operational translation for pressing a release bearing.
2. Description of Related Art
In general, while manual transmissions operate, the engine power is temporarily cut before the shift gear is engaged, and then the engine power is transmitted after the shift gear is engaged, and clutches are used for this operation.
A pedal type clutch driving device having a structure including a clutch pedal and a clutch and pressing a clutch pack connected to the clutch pedal with a force transmitted from the clutch pedal is commonly used to operate the clutch. The pedal type clutch driving device is generally used for a manual transmission.
The pedal type clutch driving device using a clutch pedal is a constant-close type, in which as a driver presses down the clutch pedal, the force pressing the clutch is removed, such that the gears can be shifted.
AMTs (Auto Manual Transmission) have been developed and practically applied to vehicle, which have the convenience of automatic transmissions, in addition to the advantages of manual transmission, with the technological development.
Further, DCTs (Double Clutch Transmission) are called a second generation AMT by using two clutches divided from the input shaft of a manual transmission and having a clutch/gear actuator.
The DCT has two clutches respectively connected to an odd-numbered shift input shaft and an even-numbered shift input shaft and is classified into a wet type similar to a wet type multi-plate type and a dry type similar to a clutch, in accordance with the clutch type.
Accordingly, the DCT is implemented in a pre-selection way that engages in advance a shift gear connected with a second clutch in traveling where a first clutch is connected with the engine, that is, shifting according to the traveling condition is performed in advance in the gear train.
The two clutches connected to the odd-numbered shift input shaft and the even-numbered shift input shaft are operated by a clutch driving device, which uses electric actuator for operating the clutches.
In general, electric actuator requires an operational structure for holding the clutch and a clutch self-opening function for ensure fail safety concept when power is cut in the vehicle.
FIG. 5 show a clutch driving device equipped with an electric actuator having the function.
As shown in FIG. 5A, the clutch driving device includes a clutch 100, a release bearing 200 changing the stroke to engage clutch 100, a lever 300 lifted to pressure release bearing 200, a reciprocating body 400 lifting lever 300 while moving in the longitudinal direction of lever 300 along support plate 310, and an actuator 500 moving forward/backward reciprocating body 400 in the longitudinal direction of lever 300, using a screw rod 510.
Actuator 500 is composed of a motor.
In this structure, a pivot point B where reciprocating body 400 moves in the longitudinal direction of lever 300 with respect to lever 300, the total force applied to release lever 200 satisfies Ft=Fs(b/a).
Ft is the total force applied to release bearing 200, Fs is lever spring tensile force, a is the distance from the pivot point B to the point of action C, and b is the distance from the point of the force A to the pivot point B.
The point of the force A is the position where reciprocating body 400 is not moved by the operation of the clutch in the entire length L of lever 300, the pivot point B is the support point of reciprocating body 400 with respect to lever 300, and the point of action C is the position where lever 300 applies force to release bearing 200.
FIG. 5B shows the relationship of force according to mechanical dynamics relationships when the clutch driving device described above operates.
As shown in the figure, as actuator 500 is operated to engage clutch 100, reciprocating body 400 moves forward in the length direction of the lever 300 by the rotation of screw rod 510 and pivot point B correspondingly moves.
Pivot point B moves in the longitudinal direction of lever 300 in accordance to the move distance of reciprocating body 400, such that the distance b from the point of the force A to the pivot point B increases and the total force Ft applied to release bearing 200 increases in the relationship Ft=Fs(b/a). Accordingly, the force applied to clutch 100 through bearing 200 increases and the clutch is strongly engaged.
As described above, a mechanical structure changing the position of the pivot point B of reciprocating body 400 in the longitudinal direction of lever 300 is used in order to variably use the lever ratio b/a in this method.
However, since the change in lever ratio b/a for operating clutch 100 is made by the positional change of the pivot point B, the change in the force of action depending on the position of the pivot point B should be reflected to lever 300. Further, since the operational force of clutch 100 is achieved by forward/backward move of the pivot point B in the longitudinal direction of lever 300, energy consumption increases.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.