摘要:
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.
摘要:
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.
摘要:
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.
摘要:
A hydraulic circuit for controlling an automatic transmission. The hydraulic circuit has a control valve connected between a shift valve and a hydraulic servomotor for actuating a frictional engagement element such as a brake in a main transmission unit. The control valve is controlled by a signal from a control means in such a manner that, when the hydraulic servomotor is drained by the operation of the shift valve to disengage the brake, the engagement of a frictional engaging element in another transmission unit is synchronized therewith.
摘要:
In an automatic transmission, friction elements are engaged and disengaged by a hydraulic servo connected alternately to a pressure source or to a drain through a selector valve, and an accumulator is connected to the line between the selector valve and the servo. The resistance against the oil discharged from the accumulator, the resistance against the oil discharged from the servo, and the return biasing forces in the accumulator and servo are adjusted so that the hydraulic pressure at the servo is lower than the hydraulic pressure of the accumulator for a predetermined time when the selector valve connects the servo with the drain. In one embodiment, a relief valve responsive to a vehicle running condition, controls the discharge rate of working oil through the drain. In another embodiment, a pressure regulator varies the level of the pressure of the working oil discharged from the accumulator in response to variations in a vehicle running condition.
摘要:
A cut-back pressure control device for a multi-speed automatic transmission includes a cut-back valve that has a spool which is controlled by both hydraulic pressure which changes in response to shifting of a sub-transmission unit between high-speed and low-speed modes and a hydraulic pressure which is established by the operation of the main transmission unit at 2nd or higher speeds. The spool is moved to a position where it interrupts the cut-back pressure when the main transmission unit selects the 1st speed while the sub-transmission unit is in the low-speed mode, whereas, when the sub-transmission unit is in the high-speed mode or when the main transmission unit selects the 2nd or a higher speed, the spool is held at a position at which it permits the supply of the cut-back pressure.
摘要:
An accumulator control device for controlling the back pressure of an accumulator includes an accumulating control valve having a first port communicating with a control oil source and a second port communicating with an accumulator back pressure chamber. The accumulator control valve is controlled by a oil pressure from a shift control. According to the control position of the shift control, the accumulator control valve controls the communicating state of the first and second ports to increase or decrease the back pressure of the accumulator.
摘要:
Described herein is a hydraulic control system for vehicular automatic transmission, including an accumulator back pressure control circuit which is provided between a line pressure conduit and a back pressure supply conduit, and comprises a first accumulator control valve for dropping the line pressure according to the throttle opening, and a second accumulator control valve receiving an input pressure commensurate with the throttle opening and dropping the output pressure of the first accumulator control valve according to the throttle opening to apply to the piston of the accumulator a back pressure varying in corresponding to the engine output shaft torque.
摘要:
A lock-up clutch control device for an automatic transmission having a torque converter with a lock-up clutch and a speed changing gear mechanism including a sub-transmission unit and a main transmission unit. The device has a lock-up operation device for producing a control signal when the sub-transmission unit is in the higher speed mode or when the main transmission unit selects 2nd or a higher speed gear. The control signal is delivered to a lock-up relay valve which operates effectively while it receives the control signal. Therefore, the torque converter can be locked up at 2nd or higher speeds of the automatic transmission which, because of various combinations of the states of the sub-transmission and main transmission units, outputs multiple speed.
摘要:
A rotational speed detecting device for detecting the rotational speed of a predetermined element of a shifting unit is provided for at least one of a main shifting unit and a sub-shifting unit. A control is provided for controlling a predetermined friction engaging element of at least one of the shifting units according to signals from the rotational speed detecting device, so that shifting operations of both the shifting units will be synchronized when both the units are shifted. Therefore, the output of speed of the transmission is not temporarily increased or decreased and thus, smooth shifting is obtained.