Aisin Seiki Kabushiki Kaisha

Advics Co., Ltd.

Hideaki Iijima

Toshihiro Nakano

Kaoru Tsubouchi

Katsuhiro Mita

Koji Suzuki

Haruo Arakawa

Hiromu Kuromitsu

Atsushi Yasuda

Shinji Sakata

Akimoto Okada

Hitoshi Ichioka

Toshiharu Okuda

Kiyohiko Minagawa

A master cylinder includes a cylinder body and primary and secondary pistons slidably received in the cylinder body, thereby defining first and second pressure chambers in the cylinder body. The first and second pressure chambers communicate with a reservoir through first and second fluid passages, respectively. During automatic brake control such as traction control or vehicle stability control, hydraulic fluid is drawn from the reservoir through the first and second pressure chambers. A throttle valve is received in each of the first and second fluid passages. The throttle valves are adapted to open while the master cylinder is inoperative and to close under backflow pressure when hydraulic fluid flows from the pressure chambers toward the reservoir. The throttle valves each include a floating valve body and a valve seat. The valve seat has its radially outer portion liquid-tightly joined and fixed to the cylinder body so that the fixed position of the valve seat and the lowermost position of the floating valve body are determined by the cylinder body.

Master cylinder

A master cylinder includes a primary piston and a secondary piston, each formed with piston ports which include two different kinds of ports, i.e. first ports for ensuring communication between a reservoir and a pressure chamber of the master cylinder, and second ports through which brake fluid is sucked from the reservoir during automatic break control. The second ports are greater in number than the first ports and are positioned forwardly of the first ports so that the second ports are closed by primary cups which are provided on the inner wall of the cylinder body so as to be in sliding contact with the respective pistons before the first ports when the respective pistons are advanced. An annular wall having a greater inner diameter than the outer diameter of the pistons is formed on the inner wall of the cylinder body to support the back of each of the primary cups. An annular groove is formed in each piston so as to communicate with the first ports. The annular groove is preferably arranged so as to radially oppose the annular wall when the piston is in an inoperative position.

A master cylinder having variable input/output characteristics includes a cylinder body in which is formed a cylinder bore and a piston fitted in the cylinder bore and movable upon brake operation. The piston is divided into a front portion and a rear portion, with a pressure chamber being defined at the front side of the front portion and an auxiliary chamber being defined at the rear side of the front portion. The auxiliary pressure chamber is located at the same position as the rear portion of the piston. A first changeover valve is provided between the auxiliary pressure chamber and the pressure chamber to establish and interrupt fluid communication between the auxiliary pressure chamber and the pressure chamber.

Master cylinder for automotive vehicle

In a master cylinder for drawing brake fluid from a reservoir through a pressure generating chamber in the master cylinder during fluid pressure control to supply brake pressure to a wheel cylinder, a check valve is provided for securing sufficient suction from the master cylinder. The check valve is operational to communicate the supply chamber and the pressure generating chamber with each other only when the pressure generating chamber is under a negative pressure while the piston is in a non-operating position. The check valve is arranged within the inner portion of the piston and along the axis of the piston.

A master cylinder includes a cylinder body including a cylinder portion, a piston fit into the cylinder portion so as to fluid-tightly divide the cylinder portion into a pressure chamber and a supply chamber, a connecting passage which is disposed in the piston and which connects the pressure chamber with the supply chamber, a valve mechanism which is mounted on the piston and which disconnects the connecting passage when the piston is moved for a predetermined distance and a restriction member installed in the connecting passage for restricting a flow of a fluid from the pressure chamber into the supply chamber when the piston is operated and allowing the flow of the fluid from the supply chamber into the pressure chamber when the piston is returned.

Master cylinder having restriction means with piston

A master cylinder includes a valve that is slidably mounted in a movable piston means for limited axial movement therein between a closed position wherein the valve is sealingly engaged with the piston and an open position wherein a gap is maintained between the valve and the piston. The valve includes a passage for providing fluid communication between the supply chamber and the pressure chamber when the valve is in the open position. An orifice in the piston limits the flow of fluid from the pressure chamber to the supply chamber at least during the limited movement of the valve from the open position to closed position. An overflow arrangement on the piston is responsive to movement of the piston against the bias of a biasing device for establishing fluid communication between the passage and the supply chamber only when the valve is in the closed position.

Growing community of inventors

Kariya, Japan

Hideaki Iijima