Abstract: A method of manufacturing a clutch housing having a boss portion and a drum portion integrally provided with the boss portion, is characterized by steps of integrally forming the boss portion and the drum portion by hot forging, and forced-cooling at least a portion of the boss portion, continuous to the integrally forming step.

Abstract: A wet-type multiple disc clutch comprises a clutch plate set having a plurality of friction plates and a plurality of separator plates alternately interposed between a clutch case and a clutch hub. An oil pressure piston slidably retained in a cylinder chamber is disposed between inner and outer cylindrical members of the clutch case and serves to fasten the clutch plate set. A canceler for defining a centrifugal oil pressure cancel chamber between the oil pressure piston and the clutch case is secured on the inner cylindrical member of the clutch case through a stop ring. A detention portion is provided on the canceler for preventing the stop ring from falling out of position.

Abstract: A method of manufacturing a clutch housing having a boss portion and a drum portion integrally provided with the boss portion, is characterized by steps of integrally forming the boss portion and the drum portion by hot forging, and forced-cooling at least a portion of the boss portion, continuous to the integrally forming step.

Abstract: A brake drum for a wet-type band brake has a large number of grooves substantially along the circumferential direction on a slide contact surface with the brake band. Each adjacent grooves are smoothly linked to each other through a substantially convex arcuate cross sectional-portion. A method for manufacturing the brake drum comprises the steps of forming the grooves by cutting work, and forming a border portion between each adjacent grooves in a substantially convex arcuate cross section by plastic working using a forming roller.

Abstract: A wet-type multiple disc clutch comprises a clutch plate set having a plurality of friction plates and a plurality of separator plates alternately, interposed between a clutch case and a clutch hub, an oil pressure piston serving to fasten the clutch plate set, slidably retained in a cylinder chamber formed between the outer tube and the inner tube of the clutch case. A canceler for defining a centrifugal oil pressure cancel chamber between the oil pressure piston and the clutch case is secured on the inner tube of the clutch case through a stop ring. Stop ring fall-out preventing means is provided for preventing a fall of the stop ring.

Abstract: A brake drum for a wet-type band brake has a large number of grooves substantially along the circumferential direction on a slide contact surface with the brake band. Each adjacent grooves are smoothly linked to each other through a substantially convex arcuate cross sectional-portion. A method for manufacturing the brake drum comprises the steps of forming the grooves by cutting work, and forming a border portion between each adjacent grooves in a substantially convex arcuate cross section by plastic working using a forming roller.

Abstract: A tube-pressed brake includes a tube for being injected with a pressure fluid to produce a pressure therein to permit transmission of a torque between two members arranged in a combination and rotating relative to each other. The tube has been applied with a coating.

Abstract: A tube-pressed brake has a tube, which is inflatable by injection of a pressure fluid thereinto such that a torque can be transmitted to a counterpart. The tube-pressed brake comprises a pressure fluid circuit for circulating the pressure fluid through an interior of the tube. The tube may be provided with a pressure fluid supply hole and a pressure fluid discharge hole, and the pressure fluid circuit may be provided with a first pressure control device arranged upstream the pressure fluid supply hole and also with a second pressure control valve arranged downstream the pressure fluid discharge hole. The pressure fluid circuit may comprise a main circuit and a pressure control circuit. Through the main circuit, the pressure fluid is allowed to successively flow through a reservoir, a pump, the first pressure control device, the tube, the second pressure control device and the reservoir in this order.

Abstract: A friction engaging device capable of obtaining a large transfer torque capacity with a compact and simple construction and smoothly connecting and disconnecting friction engaged members. A wet type multi-disc clutch has a clutch case, a hub and a main clutch. A variable length joint is provided between an inner cylindrical portion of the clutch case and a cylindrical portion of the hub. The variable length joint is constructed mainly of a first cam plate so held as to be slidable in the axial direction on the hub, a second cam plate so held as to be rotatable relatively to the clutch case, and a plurality of rollers interposed between the first and second cam plates. A tube type clutch for making the second cam plate and the clutch case frictionally engage with each other, is provided in a gap between the second cam plate and the inner cylindrical portion of the clutch case.

Abstract: In order to accurately control the operation between the fastening and liberation of a clutch piston, a cooling oil path and a drain oil path are provided independently of a clutch liberating oil path and a clutch fastening oil path, respectively.

Abstract: In addition to a first oil pump directly connected to an engine, a second oil pump is provided which is driven by an electric motor. Accordingly, a start clutch engaging pressure is applied through first and second solenoid-operated valves. The electric motor-driven pump is of the constant pressure type, and therefore its start, at the start of the automobile, can be achieved with a simple control program. After the start of the automobile, the solenoid-operated valve is switched over to the other one, so that the oil pressure is applied from the first oil pump directly connected to the engine, whereby the battery power consumption is minimized. This oil circuit is applied to various kinds of friction engagement clutches.

Abstract: In a starting clutch, an oil path for operating the clutch is provided independently of an oil path for cooling a frictional surface. That is, there is provided an oil path exclusively for cooling the frictional surface. Accordingly, a necessary amount of oil can be supplied to the frictional surface, which can thus be cooled efficiently.

Abstract: A torque converter having a lockup mechanism makes it possible to positively and forcibly suppress the frictional heat and others generated on the frictional surfaces of the lockup clutch and its counterpart while the lockup clutch is in operation, particularly in a slipping state. Hence, the life of the lockup clutch or that of the torque converter as a whole is prolonged. In this torque converter having the lockup mechanism, a hydraulic control mechanism is provided for maintaining the difference of pressure substantially at a constant level and changing the flow rate of a fluid to be supplied to the frictional surface of the lockup clutch in order to control the slipping state of the lockup clutch. Oil grooves are cut on the frictional member of the lockup clutch.