Aisin Aw Co., Ltd.

Hiroshi Niki

Masahiko Ando

Kazuhisa Ozaki

Takayuki Kubo

Shigeyasu Kozaki

A hydraulic control device for an automatic transmission capable of preventing engine racing and tie-up by controlling disengagement side oil pressure in accordance with an input torque and an oil temperature. Gear-change execution controller U controls drain timings T and T and a drain gradient &dgr;P of the disengagement side oil pressure acting on the frictional engagement elements of the disengagement side according to the magnitude of the input torque and elevation of the oil temperature in torque phase control wherein both the engagement side oil pressure and the disengagement side oil pressure are controlled.

Hydraulic control device for automatic transmission

An automatic transmission for an automotive vehicle has a plurality of friction devices for selectively coupling a number of rotary elements in a planetary gear mechanism to one another, and a hydraulic circuit for controlling changeover of the friction devices. The hydraulic circuit includes a regulator valve for generating line pressure, a manual valve for selectively changing over the line pressure to the hydraulic circuit, a plurality of shift solenoids for directly controlling engaging hydraulic pressure of the friction devices by duty control when a shift is made, and a plurality of relay valves controlled by the solenoid valves, wherein the solenoid valves are duty-controlled independently of one another. With such an arrangement, one accumulator is sufficient and the number of valves can be reduced, so that the valve body can be made more compact. In addition, highly precise shock control is possible with regard to all shift conditions.

Growing community of inventors

Anjo, Japan

Hiroshi Niki