Abstract: A hydraulic control system for an automatic transmission includes first and second passages connected to first and second engaging elements, first and second accumulators arranged with the first and second passages, and a timing valve connected to a back-pressure chamber of the first accumulator and for determining a timing for draining a first pressure within the back-pressure chamber of the first accumulator in accordance with a second pressure within a back-pressure chamber of the second accumulator.

Abstract: A system for carrying out shift control of an automatic transmission in accordance with a rotational speed of an input shaft thereof during shifting comprises calculating an input torque coefficient in accordance with torque of the engine detected and a rate of time change calculated, converting the input torque coefficient calculated into a velocity ratio, calculating a rotational speed of the input shaft of the automatic transmission in accordance with the rotational speed of the engine detected and the velocity ratio, and carrying out torque-down of the engine in accordance with the rotational speed of the input shaft calculated.

Abstract: A shift control system for an automatic power transmission is capable of optimizing operation timing of a timing valve and whereby eliminate a shift-shock and occurrence of racing.

Abstract: A brake system comprising a brake drum having an outer peripheral surface, and a brake band including a flexible band-shaped metal member having fixed and actuation brackets mounted near the opposite ends thereof. The band-shaped metal member is wound around the outer peripheral surface of the brake drum with the fixed bracket being fixed to an anchorage pin. The brake band also includes a lining member fixed on the band-shaped metal member. An actuator is coupled to the actuation bracket for acting a force on the band-shaped metal member to bring the lining member into surface contact with the outer peripheral surface of the brake drum at a speed. Oil grooves are formed in the lining member for discharging oil from a space between the lining member and the brake drum to control the speed at which the lining member comes into surface contact with the brake drum. The oil grooves have an oil discharging capacity increasing as going from the fixed bracket toward the actuation bracket.

Abstract: A speed change control device for an automatic transmission is shown which comprises first, second and third shift valves, each having two switching positions for selectively carrying out application and releasing of hydraulic pressure to and from an oil chamber of a hydraulically operated friction element. First and second solenoid valves are employed each controlling an output of hydraulic pressure in accordance with an electric signal applied thereto. The first solenoid valve outputs a hydraulic pressure for controlling the switching operation of the second shift valve, and the second solenoid valve outputs a hydraulic pressure for controlling the switching operation of the first shift valve. A passage structure is further employed which applies the hydraulic pressure from the second solenoid valve to the third shift valve to control the switching operation of the same only when the second shift valve assumes one given position.