Pressure regulating reservoir

A pressure regulating reservoir comprising:

• a housing;
• a first conduit provided at the housing and connecting a main conduit and the pressure regulating reservoir, the main conduit connecting a brake hydraulic pressure generating means for generating a brake hydraulic pressure in response to an operation of a brake operation member and a wheel braking force generating means for generating a braking force relative to a wheel;
• a second conduit provided at the housing and connecting the main conduit and the pressure regulating reservoir in order to allow the brake hydraulic pressure to be transmitted from the brake hydraulic pressure generating means to the pressure regulating reservoir through the second conduit;
• a reservoir chamber formed at the housing, connected to the first conduit and the second conduit, storing therein a brake fluid, and connected to an inlet port of a pump for sucking the brake fluid stored within the reservoir chamber;
• a first reservoir port connecting the reservoir chamber and the second conduit;
• a second reservoir port connecting the reservoir chamber and the first conduit;
• a valve portion provided at the first reservoir port and including a first hydraulic passage for allowing the brake fluid to flow therethrough from the second conduit to the reservoir chamber, a first valve body, a second valve body for closing the first hydraulic passage and a valve seat at which a second hydraulic passage, which has a larger passage area than the first hydraulic passage and which is to be closed by the first valve body, is formed;
• a piston portion including a piston for changing a volume of the reservoir chamber and a spring, which is disposed at the piston portion at a portion opposite from the reservoir chamber relative to the piston so as to bias the piston in a direction of reducing the volume of the reservoir chamber;
• a mobile member being displaceable in response to a pressure difference generated between the reservoir chamber and an opposing chamber, which is positioned so as to be adjacent to the reservoir chamber, in order to change a distance between the first valve body and the mobile member;
• a protruding portion for displacing the second valve body in response to a displacement of the mobile member in order to open the first hydraulic passage to establish a fluid communication;
• and
• a shaft for opening the second hydraulic passage by displacing the first valve body after the second valve body is displaced by the protruding portion, wherein
• in a case where the pump is not actuated, no displacement of the mobile portion occurs and the protruding portion is positioned away from the second valve body, so that the first hydraulic passage is closed by the second valve body thereby interrupting the fluid communication,
• in a case where the pump is actuated while the brake hydraulic pressure is generated by the brake hydraulic pressure generating means, the mobile member is displaced and the protruding portion displaces the second valve body, so that the pressure difference between the brake hydraulic pressure generated within the reservoir chamber and the brake hydraulic pressure generated within the first reservoir port is regulated;
• and
• in a case where the pump is actuated while no brake hydraulic pressure is generated by the brake hydraulic pressure generating means, the mobile member is further displaced and the shaft displaces the first valve body, so that the second hydraulic passage is opened to establish the fluid communication.