Abstract: A counter-force mechanism (37), which produces a counter force when a brake booster is operated, is made up of an input-side member (38) slidably disposed within a valve body (3), a second constant-pressure chamber (39) formed on the rear side of the input-side member and into which a pressure is introduced from a constant pressure chamber (A), and a second constant-pressure chamber (39) formed on the front side of the input-side member and into which a pressure is introduced from a variable pressure chamber (B). The counter force from the counter-force mechanism (37) is reduced by an orifice passage (43) as a counter-force reducing means in rapid operation of the brake.

Abstract: In a brake boosting system the present invention, as it is decided that brake assist is necessary, a pump 53 is driven, and a solenoid valve 72 is switched to its communication position, and a solenoid shut-off valve 75 is opened. Then, the pump 53 sucks brake fluid from a reservoir 9 through the solenoid valve 72 and sends out the brake fluid to the pressure intensifying chamber 21 through the solenoid shut-off valve 75. At this point, an output shaft 11 has already advanced and a radial hole 38 is positioned ahead of a seventh cup sealing member 31 so that the pressure intensifying chamber 21 and the reaction chamber 33 are shut off from the reservoir 9 so as to be in the sealed state. Therefore, pump discharge pressure is supplied to the pressure intensifying chamber 21 and the reaction chamber 33 so that the pressure in these chambers is intensified. Since the intensified pressure acts on the primary piston 12, the master cylinder pressure is intensified to a value greater than that of normal braking.

Abstract: A brake booster includes a reaction transmitting means which includes a spring that is compressed when a brake reaction from a reaction disc exceeds a preset load. A holder is mounted on a valve body, and a brake reaction which is transmitted from the reaction disc is accepted by the valve body through the holder. A plate plunger is slidably fitted in the holder to allow a brake reaction which is transmitted to the reaction disc to be transmitted to the reaction transmitting means and the valve plunger through the plate plunger. A larger outer diameter can be chosen for the spring in order to achieve a preferred preset load, and a servo ratio can be freely established by the choice of areas of contact between the reaction disc on one hand and the holder and the plate plunger on the other hand.

Abstract: An improvement of a booster as may be used in a brake of an automobile is provided. The booster is provided with pseudo-reaction imparting means (spring) which imparts a pseudo-reaction which depends on the travel of an input shaft to the input shaft. An arrangement is made in accordance with the invention such that when an input applied to the input shaft exceeds a given value, only the pseudo-reaction from the pseudo-reaction imparting means (spring) is transmitted to a driver. The arrangement enables an increased output to be reliably obtained, even by a powerless female driver, whenever a braking force of an increased magnitude is required as when using the booster as an emergency brake.

Abstract: A valve plunger, which forms part of a reaction mechanism of a brake booster, comprises a plunger member and a valve side member which are disposed to be slidable relative to each other, with a first spring disposed therebetween. A piston is slidably disposed within a valve body, and a given clearance is formed between the rear end face of the plunger member and the piston. A second spring having a greater resilience than the first spring is disposed between the piston and the valve body, and is compressed after the first spring is initially compressed. With this construction, as a brake reaction increases, the first spring is compressed to cause the plunger member to abut against the piston, and subsequently the first and second spring are compressed.

Abstract: An improvement of a valve mechanism used in the booster is disclosed. A first and a second valve seat are formed so as to face forward while a valve element is disposed so as to face rearward in opposing relationship with both valve seats. Thus, the both valve seats and the valve element are disposed in an arrangement which is opposite from that used in a conventional valve mechanism. Such an arrangement allows the atmosphere valve to be located radially outward of the vacuum valve, thus permitting the diameter of the atmosphere valve to be increased as compared with a conventional booster. This enables the operational response of the booster to be improved.

Abstract: A method of painting a portion of a shell of a brake booster which is joined together by a caulking operation. A pair of members are disposed in opposing relationship to each other, and a shear caulking operation is applied to the outer periphery thereof at a plurality of locations, thereby joining the members together to define a shell. The shell is held so as to be rotatable about its axis, and a nozzle of a paint applicator is disposed in opposing relationship with the outer periphery of the shell. By intermittently rotating the shell through a given angle, paint is applied successively to only the caulked portions.

Abstract: An apparatus for painting a portion of a two piece shell of a brake booster joined together by a caulking operation. The two pieces are disposed in opposing relationship to each other, and a shear caulking operation is applied to the outer periphery thereof at a plurality of locations, thereby joining the pieces together to define a shell. The shell is held so as to be rotatable about its axis, and a nozzle of a paint applicator is disposed in opposing relationship with the outer periphery of the shell. By rotating the shell through a given angle, paint is applied to successive caulked portions.

Abstract: In the negative pressure booster equipment of this invention, the vacuum passage to provide the communication between the control valve and the constant pressure chamber is furnished with a groove formed by the forming die of the valve body.According to the present invention, therefore, the groove is formed as the vacuum passage when the valve body is formed by a forming die of the valve body. By this groove, the sectional area of the vacuum passage is enlarged, and the air in the variable pressure chamber flows in larger quantity toward the constant pressure chamber. This causes the rapid restoration of vacuum pressure in the variable pressure chamber, and the power piston is promptly returned to the non-operating position. Because the groove is formed by a forming die, the portion with the groove is not enlarged.

Abstract: A valve mechanism for a brake booster includes a valve element and a valve seat, either of which includes a first seat through which an orifice passage is formed and a second seat. Under an intermediate load condition when a forward movement of an input shaft ceases, the first seats become engaged with each other and the orifice passage is effective to maintain a communication therethrough. Subsequently when the valve element and the valve seat are more strongly abutting together, the second seats engage to interrupt the communication.

Abstract: The invention relates to a locking arrangement for a key member used in a brake booster. A key member includes an arcuate portion which surrounds substantially one-half the perimeter of a valve body, and engaging recesses are formed at the opposite ends of the arcuate portion on the inner side. A retainer surrounds substantially one-half the perimeter of the valve body at a location opposite to the arcuate portion of the key member. The opposite ends of the retainer are formed with engaging pawls on the outer side for engaging with the engaging recesses under the resilience of the retainer. Accordingly, by merely assembling the key member and the retainer with the valve body, the engaging pawls of the retainer can be automatically engaged with the engaging recesses in the key member, thereby preventing the withdrawal of the retainer and the key member from the valve body.

Abstract: A liquid pressure booster as may be used in a brake booster or clutch booster produces an oil pressure of a level which corresponds to the magnitude of an input applied to an input shaft. The oil pressure acts upon a power piston, which then produces an amplified output in response to a small input. The oil pressure is also returned to act upon the input shaft so as to provide a reaction to the input. The invention provides a step in at least one of the input shaft and the power piston so that the combination of the step and the housing defines a pressure chamber having a pressure responsive surface at the step. A flow path switching valve selectively establishes a communication of the pressure chamber with either the power chamber or a reservoir. When the switching valve is operated, the pressure responsive area of the input shaft which is acted upon by the oil pressure can be changed, thereby changing the magnitude of the reaction transmitted to a driver.

Abstract: An apparatus for controlling braking liquid pressure produces a proportionate reduction in an input liquid pressure supplied from a master cylinder before it is output to a rear wheel cylinder. The apparatus includes a body which is formed of a single member and which is formed with a bore in which a plunger slides. An annular retainer having an inner diameter less than that of the bore is fitted into the bore at its end nearer the master cylinder. One end of the plunger extends through the annular retainer.

Abstract: A deceleration sensing valve is provided which includes a valve body adapted to move under its own inertia as the deceleration of a road vehicle exceeds a given value, and a valve seat on which the valve body seats. The valve seat is located rearwardly of the valve body as viewed in the direction of movement thereof under its inertia, whereby there can occur no change in a control pressure derived by the deceleration sensing valve, in particular when the vehicle is empty, as it does occur in the prior art in response to any slight shift in the timing when the valve body becomes seated. Consequently, when used in combination with a proportion valve, the deceleration sensing valve of the invention assures a stable braking characteristic when the vehicle is empty as well as when the vehicle is occupied.

Abstract: A deceleration sensing valve is provided which includes a valve body adapted to move under its own inertia as the deceleration of a road vehicle exceeds a given value, and a valve seat on which the valve body seats. The valve seat is located rearwardly of the valve body as viewed in the direction of movement thereof under its inertia, whereby there can occur no change in a control pressure derived by the deceleration sensing valve, in particular when the vehicle is empty, as it does occur in the prior art in response to any slight shift in the timing when the valve body becomes seated. Consequently, when used in combination with a proportion valve, the deceleration sensing valve of the invention assures a stable braking characteristic when the vehicle is empty as well as when the vehicle is occupied.