摘要:
A vehicle automatic transmission having a torque converter and a multiple stage transmission gear mechanism connected with the torque converter. The gear stage of the gear mechanism is selected in accordance with the vehicle operating condition. The transmission includes friction members. One of the friction members is engaged for a higher gear stage and disengaged for a lower gear stage whereas the other is disengaged for the higher gear stage and engaged for the lower gear stage. In shifting down from the higher gear stage to the lower gear stage, the other friction member is engaged after a predetermined time from the disengagement of the one friction member.
摘要:
An abnormality treatment device for an automatic transmission control device according to the invention comprises in input portions of signals from an engine load sensor, a vehicle speed sensor and a pressure sensor, abnormal value detection circuits for detecting any abnormal value of at least one of the signals from the sensors to generate an abnormality detection signal, and a speed range selection judgement circuit and a hydraulic control judgement circuit for generating respective abnormality treatment signals when receiving the abnormal detection signal, thereby maintaining a predetermined speed range and a predetermined high line pressure.
摘要:
A hydraulic control for a transmission wherein one drive establishing device, such as a brake, is engaged for independent drive ratios, such as low forward and reverse, at different pressure levels. A control valve is disposed between the manual control valve and the drive establishing device to admit full pressure during one drive ratio and reduced pressure during the other drive ratio.
摘要:
A circuit for controlling hydraulic pressure of an automatic transmission includes a first shift device, a second shift device and a third shift device which make line pressure lead-through by selecting the predetermined combination of supply and exhaust of hydraulic pressure in accordance with the transmission stage in order to set the transmission stage of the automatic transmission in response to the driving condition of the vehicle. A switching device detects that a hydraulic pressure is supplied to an output line of the first shift device or an output line of the third shift device so that the third-speed and the fourth-speed are switched. The switching device also detects that the hydraulic pressure is supplied to an output line of the second shift device and an output line of the third shift device so as to shut out a line which is conducted to one of engaging elements being engaged at each time of the first-speed and the third-speed. By switching the combination of the supply and exhaust of hydraulic pressure, among devices which set each of the transmission stages, the number of parts and the required space can be reduced by shutting out the switching valves of line pressure.
摘要:
A lock-up valve includes a spool movable between a clutch engagement position wherein the lock-up clutch is engaged and a clutch release position wherein the engagement of the lock-up clutch is released. A spring biases the spool toward the clutch release position. The spool has a first pressure acting area and a second pressure acting area. A fluid pressure is applied to the first pressure acting area during operation in one of the m th speed ratio and m+1 th speed ratio. An auxiliary valve is provided which allows the application of another fluid to the second pressure acting area during operation in the other speed ratio.
摘要:
A hydraulic control system for an automatic transmission including a fluid coupling type torque converter, and a gear system provided with two or more frictional devices adapted to establish two or more speed conditions. The hydraulic control system includes a hydraulic pressure source, a line pressure control valve receiving pressure from the hydraulic pressure source to generate a regulated line pressure, a throttle pressure control valve for generating a throttle pressure commensurate with the intake throttle opening, a governor pressure control valve for generating a governor pressure commensurate with the vehicle speed, a detent regulator valve receiving the line pressure to generate a regulated detent pressure, a manual valve for enabling manual shifts of the transmission, two or more shift valves for shifting the paths of the line pressure to the frictional engaging devices in response to the opposingly acting forces of the throttle pressure and governor pressure, the shift valves including one shift valve operative to establish the highest speed ratio for the transmission, and a control valve provided in the shift valve for the highest speed ratio and adapted to draw in the detent pressure when the intake throttle valve is opened substantially to a full extent, in a manner to offset the throttle pressure acting on the highest shift valve, thereby controlling the highest shift valve according to a balancing relation between the detent pressure and the governor pressure.
摘要:
A control device of a transmission fluid pressure for an electronically controlled automatic transmission comprising: a rotational number change detecting means for detecting a rotational number change of either an engine or a rotational member of an automatic transmission; a transmission fluid pressure controlling means for arbitrarily controlling a transmission fluid pressure for a transmission fluid pressure controlling device of the automatic transmission; and a control device for controlling a target value of the transmission fluid pressure for the transmission fluid pressure controlling device by a negative feed back control dependent at least on the rotational number change of either the engine or the rotational member of the automatic transmission, said control device determining whether the engine is in a constant speed or acceleration mode, and temporarily discontinuing the negative feed back control or reducing a control quantity thereof when the engine shifts from a deceleration/closed throttle mode to a constant speed or acceleration mode while the transmission fluid pressure controlling means is controlling the transmission fluid pressure for changing the gear in which the transmission to which the engine is coupled.
摘要:
The temperature of the oil (hydraulic fluid) which is used to engage the friction elements of the transmission is sensed. When the temperature exceeds a predetermined level, the level of line pressure which is used during shifting (lower than that used during non-shifting operations) is increased to compensate for the loss in viscosity and lubricative properties of the oil.
摘要:
A hydraulic fluid pressure control system for a transmission which is shifted between two speed stages via a hydraulic actuator. A line pressure regulation valve receives supply of fluid pressure from a pump and produces a regulated line pressure. A switching valve receives supply of this regulated line pressure and selectively supplies it as an operating pressure to the fluid actuator, according to the opening and closing of a pilot port. This operating pressure is also supplied to the line pressure regulation valve for increasing the regulated value of the line pressure when the fluid actuator is being operated.
摘要:
A multiple-transmission-ratio transmission arrangement includes at least first and second transmission-ratio-establishing units, for example brake bands and/or clutches, having hydraulically activated and unactivated states and operative in the hydraulically activated state for establishing respective first and second transmission ratios. An arrangement for changing the transmission ratio of the transmission arrangement comprises, in combination, a source of hydraulic activating fluid and conduits connected to the source and to the hydraulically activatable transmission-ratio-establishing units. Electrically controllable valves in the conduits are operative for alternately permitting and preventing the supply of hydraulic activating fluid to the transmission-ratio-establishing units. An electrical transmission-ratio-selecting arrangement is connected to the valves and is operative for charging the transmission ratio of the transmission arrangement by causing the valves to effect a change of state of one of the units and an opposite change of state of the other of the units. Included is an electronic timing arrangement operative during a change of transmission ratio for delaying the change of state of one of the units until after the change of state of the other of said units has been effected.