Abstract: The control system comprises a starting valve wherein an engine revolution speed indicative fluid pressure and a start adjustment fluid pressure act on a spool of the valve against each other. The starting valve generates a start pressure to be used as a clutch engagement pressure for a hydraulic clutch. The start adjustment fluid pressure is generated by a start adjustment valve coupled with an electronic control unit. Under the control of the electronic control unit, the start adjustment offsets a variation in the engine revolution fluid pressure when the engine idles with the vehicle at a standstill.

Abstract: A method and an apparatus for controlling the reduction ratio of a continuously variable transmission are disclosed wherein when an actual engine coolant temperature indicative signal is greater than or equal to a predetermined value indicative signal, a desired optimum reduction ratio signal is obtained by retrieving the desired optimum reduction ratio signal data stored in a memory versus an engine load and a vehicle speed. When the actual engine coolant temperature indicative signal is less than the predetermined value indicatiive signal, the same desired optimum reduction ratio signal data are retrieved based on a corrected signal which is obtained by correcting an engine load indicative signal or a vehicle speed indicative signal in order to provide a larger reduction ratio. Alternatively, another optimum reduction ratio signal data are retrieved when the actual engine coolant temperature indicative signal is less than the predetermined value indicative signal.

Abstract: A control system for a continuously variable V-belt transmission is disclosed wherein for the purpose of preventing an undesirable rapid drop in pressure in a cylinder chamber of a drive pulley a flow restrictor is provided to restrict the flow of oil discharged from the cylinder chamber upon rapid change in reduction ratio of the continuously variable V-belt transmission.

Abstract: A maximum reduction ratio maintaining valve is fluidly disposed between a drive pulley and a shift control valve which controls the supply of fluid to and discharge thereof from the drive pulley. The maximum reduction ratio maintaining valve drains the drive pulley to set a reduction ratio between the drive and driven pulleys at the largest reduction ratio to facilitate starting a vehicle.

Abstract: A starting valve has a start fluid pressure regulating state and a complete engagement fluid pressure regulating state and supplies a regulated fluid pressure to a hydraulic clutch. A shift operating mechanism comprises a rod movable within a reduction ratio select range and an overstroke range. A complete engagement control valve has a spool operatively connected with the rod. When the rod is disposed within the reduction ratio select range, the complete engagement control valve renders the starting valve operable in the complete engagement fluid pressure regulating state, while when the rod is disposed within the overstroke range, the complete engagement control valve renders the starting valve operable in the start fluid pressure regulating state.

Abstract: Revolution speed of a drive pulley and a parameter indicative of an output of the engine are detected. A desired value in the engine revolution speed is obtained using a predetermined function for any value in the parameter indicative of the engine output. The reduction ratio is controlled in such a manner as to maintain the revolution speed of the drive pulley in a predetermined relationship with the desired value in the engine revolution speed.

Abstract: The reduction ratio of a continuously variable transmission is controlled by a shift motor. The shift motor is controlled such that each of rotary positions thereof corresponds uniquely to a desired optimum reduction ratio. Upon detecting a state wherein a rapid shifting is needed, the shift motor is rotated at an increased revolution speed as compared to a normal revolution speed.

Abstract: A hydraulic control system comprises a line pressure regulator valve which uses a spring has non-uniform spring rate. A spring is compressed between a pressure regulating element and a member movable responsive to a reduction ratio between drive and driven pulleys. A length of the spring is varied by the member with variation in the reduction ratio. The line pressure regulator valve generates a line pressure having non-linear characteristic with respect to the variation in the reduction ratio.

Abstract: A continuously variable transmission includes a hydrodynamic device, such as a fluid coupling or a torque converter, having a lock-up clutch. The reduction ratio of the continuously variable transmission is controlled by a shift motor. The shift motor is controlled such that each of rotary positions thereof corresponds uniquely to a desired optimum reduction ratio. Upon detecting a state wherein a rapid down shift is needed, the lock-up clutch is temporarily disengaged to allow the hydrodynamic device to slip during the rapid down shift.

Abstract: A hydraulic control system disclosed herein comprises a line pressure regulator valve which regulates the fluid supplied from a pump to provide a line pressure variable at least depending upon output torque of the engine. The line pressure is supplied to a shift control valve which regulates the fluid supply to and discharge from cylinder chambers of drive and driven pulleys.

Abstract: A method and a system for controlling a continuously variable transmission are disclosed wherein, upon varying fluid pressure within a cylinder chamber of a drive pulley, fluid pressure within a cylinder chamber of a driven pulley is kept constant, while, upon varying the fluid pressure within the cylinder chamber of the driven pulley, the fluid pressure within the drive pulley is kept constant.

Abstract: A continuously variable V-belt transmission comprises a hydrodynamic transmission unit including a lock-up means. A switch valve is provided which is responsive to fluid pressure in a cylinder chamber of a drive pulley, which fluid pressure being indicative of the reduction ratio of a continuously variable V-belt transmission unit. The lock-up means is engaged in response to the state of the switch valve to lock the hydrodynamic transmission unit when the reduction ratio is small. The switch valve may be responsive to stator reaction of a stator of the hydrodynamic transmission unit so that the lock-up means is released as long as the hydrodynamic transmission unit multiply torque.

Abstract: A continuously variable V-belt transmission comprises a V-belt running over drive and driven pulleys, each having an axially fixed conical disc, axially movable conical disc and a cylinder chamber for moving the axially movable conical disc. At least one of the pulleys has a compensation chamber which is separated from the cylinder chamber by a partition wall member. The compensation chamber is enclosed by the partition wall member, cylinder wall and trough including an annular disc like portion directed inwardly of the cylinder wall. The trough has a tubular portion directed axially from the disc like portion. A passage is formed and is so directed that flow of fluid from an outlet port of a torque converter is guided by the tubular portion toward the compensation chamber.

Abstract: According to the present invention, a parking gear is rotatable with that rotary member which is in driving connection with a differential. The rotary member is released from a continuously variable V-belt transmission unit upon setting a manual shift lever in "P" position. When the manual shift lever is set to the "P" position, the parking gear is locked.

Abstract: A continuously variable transmission comprising driving and driven pulleys and a V-belt interconnecting these pulleys. A forward gear is rotatably mounted on a driven shaft and a multiple disc friction clutch is mounted within the driven pulley and operative to connect the driven pulley to the forward gear.

Abstract: A continuously variable V-belt transmission comprises means for producing a signal indicative of state of a hydrodynamic transmission unit which is drivingly connected to a continuously variable V-belt transmission unit. A line pressure regulator valve regulates fluid supplied by a pump in response to the signal to produce a line pressure variable depending upon the state of the hydrodynamic transmission unit.

Abstract: A countershaft-type automatic power transmission in which a countershaft gear assembly is operated by a hydraulic control system controlled by electric control means responsive to various operational variables of a vehicle and in which a clutch assembly is operated between the coupled and uncoupled conditions by clutch control valve means which is also controlled by the electric control means, the power transmission further featuring throttle valve control means adapted to move the carburetor throttle valve to a position to produce an idling condition in the engine independently of the accelerator pedal when the clutch assembly is in the uncoupled condition.