Abstract: In a friction disc clutch assembly of the type including a flywheel secured to a drive shaft, a clutch cover having an outer peripheral rim secured to the flywheel by means of a plurality of circumferentially spaced bolts and being formed with an internal cylindrical surface, a pressure plate mounted within the clutch cover in such a manner as to be rotatable with and axially displaceable with respect to the flywheel, a diaphragm spring assembled within the clutch cover to bias splined to a driven shaft and interposed between the flywheel and the pressure plate, the outer periheral rim of the clutch cover is formed with a radial exhaust hole located between each pair of the circumferentially spaced bolts and extending outwardly from the internal cylindrical surface of the clutch cover to exhaust muddy water entered into the interior of the clutch cover.

Abstract: A friction clutch wherein a clutch disc is disposed between a flywheel, and a pressure plate fixed to the flywheel via a clutch cover secured to the flywheel, such that the clutch disc is normally held in pressed contact with the flywheel and pressure plate, with the pressure plate biased by a diaphragm spring against the clutch disc. The diaphragm spring engages the clutch cover at its outer end and engages a releasing member at its inner end, such that the spring normally biases the pressure plate at its intermediate portion. The clutch disc is released from the flywheel and pressure plate when the releasing member is operated to free the pressure plate from the biasing action of the spring. The friction clutch has a stopper device for limiting a maximum permissible length of axial displacement of the pressure plate toward the clutch disc due to wear of the clutch disc. This length is determined to the smaller than X.multidot.

Abstract: A clutch master cylinder comprises a master cylinder body provided thereon with a fluid reservoir tank and therein with an inlet port in communication with the reservoir tank and an outlet port for connection to a slave cylinder, a piston axially slidably disposed within the cylinder body and arranged to be moved inward by a push-rod, a valve seat arranged between the inlet and outlet ports within the cylinder body to permit fluid flow passing therethrough, a valve body associated with the piston to cooperate with the valve seat in response to inward movement of the piston, a fixed plug mounted on the cylinder body, and an adjusting plug disposed within the cylinder body to adjust an axial space between the valve seat and the valve body, the adjusting plug having an outer end portion adjustably threaded into the fixed plug and fastened in place by a lock nut threaded thereon and being provided at an intermediate portion thereof with an annular flange engageable with the inner end of the fixed plug to restrict

Abstract: A clutch release mechanism permitting a center fulcrum type release fork to be installed or removed under such condition that a clutch housing is fixed to a cylinder block, so as to simplify installation of the release fork in a production step and also simplify subsequent exchange of the release fork. The clutch release mechanism comprises a release fork having a pair of forked arms and adapted to be inserted from a fork insertion hole formed through a part of a clutch housing and mounted to a bearing hub of a clutch release bearing in a direction perpendicular to an axis of the bearing hub so as to be interlocked with the bearing hub, a fulcrum pin fixed to base portions of the forked arms of the release fork at both ends thereof, and a fork support fixed to an inside wall of the clutch housing for rotatably supporting the fulcrum pin.

Abstract: In a clutch of the type including a fork inserting hole formed at a certain position of a side wall of a clutch housing, so as to insert and install a clutch release fork from an outer side of the clutch housing, a clutch ventilation structure comprises a ventilation duct which has a L-shaped ventilation passage therein and which is mounted to the fork inserting hole. An inner end of the ventilation passage is open into the clutch housing, and an outer end of the ventilation passage is open to the atmosphere. With this arrangement, ventilation of the inside area of the clutch housing may be smoothly carried out by effectively utilizing the fork inserting hole without closing the hole with a blind plug, thereby improving a cooling effect of the clutch.

Abstract: A mounting structure for a clutch booster assembly to be arranged adjacent to and in front of a vacuum brake booster assembly fixed to a forward fire-wall structure of a vehicle body. A bracket member of a U-shaped cross-section fixed to the fire-wall structure opens toward one side of the brake booster assembly and supports the clutch booster assembly on its front end. A flexible tubular cover member has a front end secured to the front end of the bracket member to hermetically enclose a rear air suction opening of the clutch booster assembly and a rear end coupled within an opening of the fire-wall structure, and a flexible tubular sealing boot has a front end secured to the rear end of the cover member and a rear end secured to an operation rod of the clutch booster assembly. The sealing boot is provided with an annular lip in engagement with the front face of the fire-wall structure and at its rear end with a vent hole.

Abstract: Disclosed herein is a clutch disc comprising a thrust plate incorporated between the first frictional plate, which is interposed between the subdisc plate and the hub flange, and the hub flange, so as to rotate relatively to the hub flange within the range of slight angular displacement corresponding to the amount of play defined between the pawl portion of the thrust plate and the cutaway portion of the aperture opened through the hub flange, and a frictional plate fixed to the thrust plate on the flange side, said frictional plate having a smaller frictional coefficient than the first frictional plate.

Abstract: A twin-plate clutch comprises an annular intermediate plate interposed between a fly wheel and a pressure plate, a first clutch disc interposed between the intermediate plate and the fly wheel, and a second clutch disc interposed between the intermediate plate and the pressure plate, wherein the first clutch disc is provided with facings fixed to an outer circumferential portion of a disc plate thereof under a condition of no cushioning function in an axial direction of the first clutch disc, and the second clutch disc is provided with cushion springs fixed to an outer circumferential portion of a disc plate thereof and facings fixed on both sides of the cushion springs. With this arrangement, an amount of axial movement of the second clutch disc of the twin-plate clutch is rendered small, thereby suppressing increase in a pedal stroke and reducing wear between a clutch hub of the second clutch disc and an input shaft.