1. Industrial Useful Field
This invention relates to an intermediate plate positioning mechanism for a twin clutch having two clutch discs with an intermediate plate sandwiched therebetween.
2. Prior Art and its Problem
As illustrated in FIG. 8, a conventional twin clutch 100 is generally composed of a first clutch disc 103 pressed on a flywheel 101, an annular intermediate plate 104 pressing the first clutch disc 103 on the flywheel 101, a second clutch disc 105 pressed on a back face of the intermediate plate 104 and an annular pressure plate 106 pressing the second clutch disc 105 on the back face (right side of FIG. 8) of the intermediate plate 104, which are all housed respectively concentrically in an inside of a clutch cover 102 secured to an outer peripheral part of the flywheel 101. Various positioning mechanisms at a time of clutch disengagement have been proposed for the intermediate plate 104 disposed between the first clutch disc 103 and the second clutch disc 105.
A construction is well known, wherein a stopper pin 112 extending in a longitudinal direction (lateral direction of FIG. 8) is passed through a hole 111 on an outer peripheral part of the intermediate plate 104. A supporting part 120 for contacting with the stopper pin and secured to the flywheel 101 in such a manner as covering an outer peripheral side of the pressure plate 106 is provided. The flywheel 101 is connected to the intermediate plate 104 by an elastic strap 121. The stopper pin 112 is elastically fitted in a hole of an annular stopper spring 114 in such a manner that the stopper pin 112 is able to slide only backward in relation to the stopper spring 114. Stopper spring 114 is held between the elastic strap 121 and the intermediate plate 104, as illustrated in an upper part of FIG. 8 for example (Japanese Patent Publication No. 63-27724, for example).
According to the above-mentioned structure, a backward movement of the intermediate plate 104 is restricted by the stopper pin 112 so that a prescribed return stroke L (backward movement of the intermediate plate 104) can be correctly insured at the backside of the intermediate plate 104.
However, a friction facing 105a of the second clutch disc 105 is apt to wear out earlier than a friction facing 103a of the first clutch disc 103 because the facing 105a rubs against the pressure plate 106 forming a rotating member in advance of the friction facing 103a at a time of clutch engagement. Consequently, when the clutch is kept operating under a state where only the friction facing 105a is excessively worn out, a clearance (a distance between the intermediate plate 104 and the friction facing 105a) becomes larger than an initial dimension so that this clearance does not correspond with the return stroke L.