GB1223333A - Improvements in or relating to apparatus for automatically adjusting the clearance of a motor vehicle clutch - Google Patents

Abstract

1,223,333. Clutch release mechanisms. DAIKIN SEISAKUSHO K.K. 3 April, 1968 [19 April, 1967; 12 May, 1967 (2)], No. 16104/68. Heading F2L. Wear compensating apparatus for the gap between a clutch release yoke 21, Fig. 1, and a release bearing 20 comprises a release cylinder 5 having first and second flow paths arranged so that depression of the clutch pedal 1 causes the yoke 21 to close the gap a and disengage the clutch, a switching valve 6, 8, 11 closes one of the flow paths at the moment the yoke disengages from the bearing thereby obstructing return movement of the release piston 23 and a piston 13 in the release cylinder allows the release piston to recede an additional amount proportional to the gap which is thereby maintained regardless of any wear at the clutch facing. Depression of pedal 1 causes oil flow through duct 4 and passage 18 into chamber 24 causing downward movement of piston 13 which in turn causes oil flow from chamber 7 into the release cylinder 3, the piston 23 being moved to the left to disengage the clutch. Clearance b disappears as yoke 21 contacts the release bearing 20 and as further oil enters chamber 12 the valve member 11 is raised to allow oil to flow directly into the release cylinder via ports 7, 6 so that the release piston is moved further to the left in the clutch releasing direction. When the pedal is released the action of springs 25, 30 moves the release piston to the right. When the yoke 21 disengages from the release bearing spring 8 overcomes spring 25 causing the valve member 11 to move to the Fig. 1 position in which the oil flow via port 6, chamber 12 and port 7 and further return movement of piston 23 is prevented. Spring 15 is compressed as the piston 13 rises allowing a further movement of the release piston 23 to maintain the gap a. In another embodiment the piston (13), Fig. 4 (not shown), and valve member 11 are in separate cylinders in a housing 5, the gap being maintain in the same way as in Fig. 1. In a further embodiment depression of the clutch pedal causes the release piston 23a, Fig. 6, to be moved to the left and pressure oil passing through piston 13 also causes the latter to be moved outwardly. Further depression of the clutch pedal causes the yoke 21 to engage the release bearing, valve member 11 being lifted and oil flows via ducts 7, 6a, 6b to move all pistons 23a, 13 and 23b outwardly into the Fig. 6 position. When the clutch pedal is released springs 25, 30 return the release piston 23a. Until yoke 21 separates from the release bearing 20 valve 11 remains in its upper position so that pistons 13, 23b can return whilst maintaining clearance b. After the separation the valve member 11 descends to close duct 6b preventing any further return of the release pistons 23b, but piston 13 and therefore piston 23a is permitted to return by an amount equal to the clearance b to form a gap between the yoke and the release bearing.