Tokico, Ltd.

Satoru Suga

Hiromi Ando

Kenji Sano

Kunihiro Matsunaga

A dual function brake fluid control apparatus is presented for performing antiskid operation as well as another control operation involving control of the fluid pressure when the apparatus is not performing an antiskid operation. The apparatus is provided with a pressure relief valve having a valve body and a piston. The relief valve is forced closed by a biasing spring acting on a valve body, and when in the open state relieves the discharge pressure of a pump to the intake side of the pump. The piston closes the relief valve when the fluid pressure from the master cylinder exceeds a specific value. This configuration allows setting the discharge fluid pressure of the pump to apply fluid pressure to the wheel cylinders for non-antiskid control operations higher than that for the antiskid control operation. During an antiskid control operation, the fluid pressure relief valve also allows to maintain the discharge fluid pressure of the pump at the same value as or higher than the fluid pressure generated in the master cylinder.

Brake fluid pressure control apparatus

The present invention relates to a brake fluid pressure control apparatus in which a casing contains a pump communication port separately from a master cylinder communication port. A spool is also provided which limits the communication between the pump communication port and the master cylinder communication port in a manner such that the discharge pressure from the pump is not added directly to the master cylinder. Additionally, in the intake and discharge sides of the pump, a bypass channel is provided. In this bypass channel, a relief valve is provided which allows the escape of pressure force to the intake side of the pump in the case when the pressure force between the discharge side of the pump and the flow control valve increases to a high pressure. Furthermore, because the brake fluid is normally designed to be discharged from the pump to the flow control valve at approximately a fixed flow rate by means of the relief valve, there is no return of brake fluid to the master cylinder via the flow control valve, and stroke fluctuations of the master cylinder can be eliminated. Additionally, the necessity for providing an orifice between a pump communication port and the master cylinder communication port disappears.

The present invention relates to a brake fluid pressure control apparatus in which a casing contains a pump communication port separately from a master cylinder communication port. A spool is also provided which limits the communication between the pump communication port and the master cylinder communication port in a manner such that the discharge pressure from the pump is not added directly to the master cylinder. Additionally, in the intake and discharge sides of the pump, a bypass channel is provided. In this bypass channel, a relief valve is provided which allows the escape of pressure force to the intake side of the pump in the case when the pressure force between the discharge side of the pump and the flow control increases to a high pressure. Furthermore, because the brake fluid is normally designed to be discharged from the pump to the flow control valve at approximately a fixed flow rate by means of the relief valve, there is no return of brake fluid to the master cylinder via the flow control valve, and stroke fluctuations of the master cylinder can be eliminated. Additionally, the necessity for providing an orifice between a pump communication port and the master cylinder communication port disappears.

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Yamanashi, Japan

Satoru Suga