Aisin Seiki Kabushiki Kaisha

Noriyoshi Kondoh

Suguru Futamura

Shigeo Takahashi

Eiji Sugiura

A fluid pressure control circuit for a transmission, includes plural electromagnetic valves each switching one of engagement elements between an engaged state and a disengaged state, plural passages configured to connect the engagement elements to a fluid pressure source, a first electromagnetic valve corresponding to one of the electromagnetic valves and switching one of the engagement elements between the engaged and disengaged states, a second electromagnetic valve corresponding to another of the electromagnetic valves and switching another of the engagement elements between the engaged and disengaged states, and a shut-off valve, when the first electromagnetic valve and the second electromagnetic valve are open, closing the passages among the first electromagnetic valve, the engagement elements switched by the first electromagnetic valve and the fluid pressure source with the use of the fluid pressure to establish a closed state, and maintaining the closed state with the use of the fluid pressure.

Fluid pressure control circuit for transmission

A hydraulic control apparatus for an automatic transmission which supplies a controlled hydraulic pressure to a engagement element includes a control valve unit including a line pressure input port, an output port for outputting the controlled hydraulic pressure, a spool for selectively opening and closing the line pressure input port and the output port, a spring for biasing the spool in one direction, a feedback hydraulic chamber, a pilot pressure chamber, a pilot pressure control device, a sleeve, a plunger positioned inside of the sleeve, and at least one plunger hydraulic chamber for pushing the plunger when the controlled hydraulic pressure is introduced therein so as to push the spool in a direction against the biasing direction of the spring. The hydraulic control apparatus further includes a switching device provided at a hydraulic passage between the output port and the plunger hydraulic chamber and for selectively establishing a communication therebetween.

Hydraulic control apparatus for automatic transmission

A hydraulic pressure control device for an automatic transmission in which a single control valve selectively applies control pressure to friction elements includes a control valve and a shift valve. The control valve has a control port from which control pressure is outputted after being adjusted by a linear solenoid valve, and first and second feedback ports to which the control pressure is fed back. The shift valve is positionable in a first position when the control pressure is applied to the first friction element and a second position when the control pressure is applied to the second friction element, and is adapted to lower the control pressure outputted by the control valve in the second position of the shift valve by controlling communication of the control port with the feedback ports. In addition, an ON-OFF solenoid valve switches the position of the shift valve.

Hydraulic pressure control device for an automatic transmission

To reliably establish a shift in a hydraulic pressure control device for an automatic transmission in which a control valve applies a control pressure, by way of a shift valve, to a plurality of friction engaging elements, the hydraulic pressure control device is designed to establish an intermediate shift pattern. The hydraulic pressure control device includes an electronic control unit that establishes shift pattern to produce the second and third gear stages and shift pattern to produce the third, fourth and fifth gear stages in which ON-OFF solenoid valves under energization are combined to produce both the second and third gear stages. The hydraulic pressure control device also establishes shift pattern during the transfer from shift pattern to shift pattern which prevents application of the control pressure from one of the control valves supplying control pressure to one of the friction engaging elements in the shift pattern , with the ON-OFF solenoid valves under energization being combined to produce the third gear stage.

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Nagoya, Japan

Noriyoshi Kondoh