Abstract: A hydraulic operating unit for the friction engaging apparatus of a transmission provides a hydraulic operating unit which permits the introduction of a low-pressure working fluid to permit the forceable disengagement of the hydraulic operation unit to work against the fluid which would normally urge the unit into engagement. The effective pressure-receiving area on the releasing side of a hydraulic power servo mechanism is made sufficiently large with respect to the effective pressure-receiving area on the engaging side of the servo mechanism while the piston diameter is kept small in order to save space in the construction of the servo mechanism while at the same time permitting the device to effectively disengage the friction mechanism.

Abstract: An end of a shaft member which is displaced and actuated in conjunction with a shift lever of a transmission presses and displaces a latch which is arranged in such a way as to be able to be displaced in an opposing direction against a cam surface of a cam which is formed on a fixed member to function like a wedge which wedges itself between said cam surface and latch, thereby making the latch engage teeth which are drivingly coupled to an output shaft of the transmission in a parking mechanism of a transmission. A cylindrical support portion is continuously extended from the cam surface so as to guide the end of the shaft member at the time when the end of the shaft member is disengaged from the area between the cam surface and latch.

Abstract: The transmission of the invention is capable of attaining a plurality of shift ranges by locking and releasing one or more elements of a gear mechanism to a casing of the transmission or by connecting and releasing the elements with the input shaft, the output shaft or into and out of engagement with each other. The control system for controlling the action of the elements of the gear set is a hydraulic control system having friction elements which achieve a higher speed range and a lower speed range of the transmission upon actuation by servo valves. An additional servo valve is included to work in opposition to one of the other servo valves and communicates with another of the servo valves. A communication control valve is disposed in a hydraulic line which communicates with another of the servo valves and with the servo valve acting in opposition so as to control the communication between these valves in response to a signal pressure developed by a signal pressure valve.

Abstract: A control apparatus in an automatic transmission includes first and second shift valves which are independently actuable to define four distinct states corresponding to four speed ranges of the transmission. In the first state, neither valve participates in achieving the first range. In the second state, only the first valve participates in achieving the second range. In the third state, only the second valve participates in achieving the third range. In the fourth state, both valves participate in locking a lock-up clutch by being fluidly interconnected by an interconnecting passage so as to define a signal pressure passage which conducts a signal pressure to a lock-up relay valve to implement a locking of the lock-up clutch.

Abstract: A control system for an automatic transmission equipped with a plurality of friction engaging devices for attaining a plurality of shift ranges by locking the elements of a gear mechanism, which is disposed between an input shaft and an output shaft, to a case, by bringing the elements into and out of engagement with the input shaft or output shaft, or into and out of engagement with each other, said friction engaging devices including a first friction engaging device (C2) which takes part in achieving a reverse shift, and a second friction engaging device (B2) which participates in achieving parking and reverse the control system includes an electronic control circuit means which controls the timing of the actuation of the first and second friction engaging devices upon shifting from parking to reverse range so as to mitigating shock upon gear shifting.

Abstract: A governor valve comprising a housing provided with inlet and outlet ports; a rotational shaft provided within the housing; a body rotatably supported by the housing and operatively connected to the rotational shaft; a valve spool slidably disposed within the body for controlling the communication between the inlet and outlet ports; a ball cage slidably disposed within the body and being provided with a plurality of cylindrical portions radially and outwardly extended therefrom; a plurality of ball members slidably inserted into the plurality of cylindrical portions of the ball cage; and a cam member provided with a tapered face for receiving a centrifugal force of the plurality of ball members.

Abstract: A hydraulic control system for a vehicle transmission including a plurality of hydraulically operated functional brake and clutch devices for providing a plurality of driving stages of different speed ratios, the system comprising a pressure regulator valve for providing a regulated line pressure and shift valves for transmitting the line pressure to selected ones of the frictional devices. Pressure control valves are provided between the shift valves and the brake or clutch devices which are operated in low speed range of the transmission to provide a time delay in the increase of the pressure for actuating the devices. The pressure regulator valve is provided with pressure increasing chambers which receive the outlet pressure from the pressure control valves to increase the line pressure when the transmission is shifted to the low speed range such as the first and second speed forward drive stage and the reverse drive stage.