JPS6181464U - - Google Patents

Description

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a hydraulic brake system for an automobile equipped with an anti-skid device which is an embodiment of the present invention, and FIG. 2 is a front sectional view showing the master cylinder of FIG. FIG. 3 is a sectional view of a main part of a master cylinder according to another embodiment of the present invention. 10: Reservoir tank (first reservoir), 1
2: Master cylinder, 16: Cylinder bore, 20
: first piston, 22: second piston, 24: first pressure chamber, 26: second pressure chamber, 32: first compression coil spring, 34, 36, 172, 174: spring receiver, 38: second compression coil Spring, 40: Brake pedal, 42: First supply chamber, 44: Second supply chamber,
46, 48: Supply port, 54, 56: Communication path, 58: First cup seal, 60: Second cup seal, 62: First relief port, 64: Second relief port, 80, 81: Rear wheel, 82, 8
4: Rear wheel cylinder, 86, 88: Front wheel,
90, 92: Front wheel cylinder, 94:
Switching valve, 96: Electromagnetic control valve, {98: Master cylinder side passage, 100: Intermediate passage, 102: Wheel cylinder side passage} (main liquid passage), 108: Reservoir passage, 110: Reservoir (second reservoir)
, 120: pump, 124: pump passage, 156
: Third output port, 160, 170: Valve element (valve device), 164, 176: Compression coil spring (elastic member), 165: Engaging portion, 166: Bypass passage,
168: Check valve, 171: Retaining ring (stopper means), 176: Compression coil spring (elastic member), 17
8: Tension member.

Claims (1)

[Claims for Utility Model Registration] (1) When the piston with the cup seal is retracted to its original position in the cylinder bore, the relief port communicates the pressure chamber in front of the piston with the first reservoir so that the brake fluid is The state allows communication between the pressure chamber and the first reservoir, but after the outer circumferential end of the cup seal passes through the relief port as the piston moves forward, the pressure chamber and the first reservoir A master cylinder whose communication with the relief port is cut off and hydraulic pressure is generated in its pressure chamber, and a main liquid passage that guides the hydraulic pressure generated in the pressure chamber of the master cylinder to a brake cylinder provided in a wheel brake. It is provided in the middle of the main fluid passage, and is switched by the controller between a pressure increase permitting state in which the brake cylinder is communicated with the master cylinder and a pressure drop permitting state in which the brake cylinder is communicated with the first reservoir or a second reservoir separate from it. and an electromagnetic control valve that controls the hydraulic pressure of the brake cylinder so that the slip rate of the wheel becomes an appropriate value; In an anti-skid device, the anti-skid device includes a pump that supplies a portion of the main liquid passageway between the electromagnetic control valve and the brake cylinder, and a pump that supplies a pump to a portion of the main liquid passageway that connects the electromagnetic control valve and the brake cylinder. A bypass passage that bypasses the electromagnetic control valve is provided between the pressure chamber of the master cylinder and a check valve whose forward direction is in the direction from the pressure chamber of the master cylinder toward the brake cylinder. Further, the opening of the bypass passage on the master cylinder side is normally open to allow communication between the pressure chamber and the bypass passage, but the piston is connected to the relief port and the pressure chamber by the cup seal. An anti-skid device characterized by being provided with a valve device that closes in conjunction with the movement of the piston to cut off communication between the pressure chamber and the bypass passage after the piston advances a short distance beyond a position where communication with the pressure chamber is cut off. . (2) An opening on the master cylinder side of the bypass passage is provided to open at the bottom surface of the cylinder bore, and the valve device is provided so as to be movable in a direction parallel to the moving direction of the piston, and is provided with an elastic member. A valve element is provided that is biased toward the bottom surface of the cylinder bore, and the valve element is movable relative to the piston, but is engaged in a state in which it cannot be separated from the piston beyond a certain limit, and the valve element is always engaged with the piston so that it cannot be separated from the piston beyond a certain limit. The bypass passage and the pressure chamber are brought into communication by being retracted from the position where it contacts the bottom surface of the cylinder bore by engagement with the piston, and the piston is brought into communication with the relief chamber by the cup seal. After the valve element advances beyond a position where communication between the port and the pressure chamber is cut off, the elastic member presses the valve element against the bottom surface of the cylinder bore, thereby cutting off communication between the bypass passage and the pressure chamber. An anti-skid device according to Claim 1 of the Utility Model Registration Claim. (3) An opening on the master cylinder side of the bypass passage is provided to open at a side surface of the cylinder bore, and the valve device includes a valve element slidably fitted into the cylinder bore, and the valve element is provided with a valve element slidably fitted into the cylinder bore. connected to the piston in a state in which the elastic member is prevented from elongating beyond a certain level by a tension member, and is prevented from being separated from the piston by a certain distance;
Also, a stopper means is provided for preventing the valve element from moving forward beyond a position where it closes the opening of the bypass passage, and the valve element is normally brought into contact with the stopper means by the piston via the elastic member. By retreating from the contact position, the bypass passage and the pressure chamber are brought into communication; however, after the piston moves forward beyond the position where communication between the relief port and the pressure chamber is cut off by the cup seal, Utility model registration claim No. 1, wherein the valve is pressed against the stopper means by the biasing force of the elastic member and maintained at the forward end position, thereby cutting off communication between the bypass passage and the pressure chamber. The anti-skid device according to item 1.