Vehicle brake device and its reservoir

Abstract

A vehicular braking apparatus including a shut-off valve for shutting off, as needed, a flow of oil from a wheel cylinder to a master cylinder; a pressure increase-decrease control valve increasing and decreasing a pressure in the wheel cylinder; a reservoir receiving and storing in a reservoir chamber the oil from the wheel cylinder when the pressure increase-decrease control valve is in a pressure decrease position; a pump sucking in and pressuring the oil from the reservoir chamber and supplying the oil to the wheel cylinder via the pressure increase-decrease control valve when the pressure increase-decrease control valve is in a pressure increase position; and a communication control valve controlling communication between the master cylinder and the reservoir chamber. The communication control valve is a normally-closed valve and is opened by a suction pressure of the pump.

1 . (canceled) 
     
     
         2 . A vehicular braking apparatus comprising:
 a shut-off valve that shuts off, as needed, a flow of a working liquid from a wheel cylinder to a master cylinder;   a pressure increase-decrease control valve that increases and decreases a pressure in the wheel cylinder;   a reservoir that receives and stores in a reservoir chamber the working liquid from the wheel cylinder when the pressure increase-decrease control valve is in a pressure decrease position and at a time when the working liquid in the master cylinder is pressurized;   pressurizing supply means for sucking in and pressurizing the working liquid from the reservoir chamber and supplying the working liquid to the wheel cylinder via the pressure increase-decrease control valve when the pressure increase-decrease control valve is in a pressure increase position; and   a communication control valve that controls communication between the master cylinder and the reservoir chamber;   wherein,   the communication control valve includes a normally-closed on-off valve, and valve-opening means for opening the on-off valve by being driven by means of the suction pressure of the pressurizing supply means;   the normally-closed on-off valve comprises a valve element and a valve element-urging member for urging the valve element to a close position, and the communication control valve maintains a closed condition at the time of nonbraking;   the valve-opening means includes a reciprocally movable member disposed within the reservoir so as to be reciprocally movable in a direction of opening and closing of the on-off valve and that is driven in a direction of opening of the on-off valve by means of the suction pressure of the pressurizing supply means;   the direction of opening of the on-off valve is a direction of reduction of a volume of the reservoir chamber;   the on-off valve is a check valve which includes a valve element and valve-element-urging means for urging the valve element against a valve seat and that closes through the valve element touching the valve seat and opens through the valve element moving away from the valve seat; and   the valve element is in a form of a poppet including a head portion and a spool portion smaller in diameter than the head portion and is supported at the spool portion by a valve housing in a reciprocally movable manner, and the on-off valve closes through the head portion touching the valve seat and opens through the head portion moving away from the valve seat.   
     
     
         3 . A vehicular braking apparatus according to  claim 2 , wherein, until the suction pressure of the pressurizing supply means attains a predetermined value or greater, the working liquid can flow from the reservoir to the pressurizing supply means in a state in which the communication control valve maintains a closed condition. 
     
     
         4 . A vehicular braking apparatus according to  claim 2 , wherein, when an amount of movement of the reciprocally movable member in the direction of opening of the on-off valve from a position at the time of nonbraking is equal to or less than a preset amount of idle movement, the valve-opening means does not open the on-off valve. 
     
     
         5 . A vehicular braking apparatus according to  claim 2 , wherein the reservoir has a housing, a reservoir piston disposed within the housing in a reciprocally movable manner and that defines the reservoir chamber in cooperation with the housing, and piston-urging means for urging the reservoir piston in the direction of reduction of the volume of the reservoir chamber, and the reservoir chamber communicates at all times with a suction side of the pressurizing supply means and communicates with the master cylinder via the communication control valve. 
     
     
         6 . A vehicular braking apparatus according to  claim 2 , wherein the valve element, in cooperation with the valve housing, defines a variable-volume chamber whose volume increases and decreases according to a reciprocal movement of the valve element so as to allow the reciprocal movement of the valve element, and includes an internal passage for establishing communication at all times between the variable-volume chamber and the 
       reservoir chamber. 
     
     
         7 . A reservoir provided in a vehicular braking apparatus comprising:
 a shut-off valve for shutting off, as needed, a flow of a working liquid from a wheel cylinder to a master cylinder;   a pressure increase-decrease control valve that increases and decreases a pressure in the wheel cylinder;   pressurizing supply means for pressurizing the working liquid and supplying the working liquid to the wheel cylinder via the pressure increase-decrease control valve at a time when the pressure increase-decrease control valve is in a pressure increase position and the working liquid in the master cylinder is pressurized, the reservoir receiving and storing in a reservoir chamber the working liquid from the wheel cylinder when the pressure increase-decrease control valve is in a pressure decrease position, the reservoir chamber communicating with a suction side of the pressurizing supply means; and   a communication control valve that controls communication between the master cylinder and the reservoir chamber;   wherein,   the communication control valve includes a normally-closed on-off valve, and valve opening means for opening the on-off valve by being driven by means of the suction pressure of the pressurizing supply means; the normally-closed on-off valve comprises a valve element and a   
       valve element-urging member for urging the valve element to a close position, and the communication control valve maintains a closed condition at the time of nonbraking;
 the valve-opening means includes a reciprocally movable member disposed within the reservoir so as to be reciprocally movable in a direction of opening and closing of the on-off valve and that is driven in a direction of opening of the on-off valve by means of the suction pressure of the pressurizing supply means; 
 the direction of opening of the on-off valve is a direction of reduction of a volume of the reservoir chamber; 
 the on-off valve is a check valve which includes a valve element and valve-element-urging means for urging the valve element against a valve seat and that closes through the valve element touching the valve seat and opens through the valve element moving away from the valve seat; and 
 the valve element is in a form of a poppet including a head portion and a spool portion smaller in diameter than the head portion and is supported at the spool portion by a valve housing in a reciprocally movable manner, and the on-off valve closes through the head portion touching the valve seat and opens through the head portion moving away from the valve seat.