Abstract: A valve seat (50) is provided on and along the end face of the end tubular portion (16a) of the valve body (16) of a power brake device. A valve member (49) is slidably put on the input shaft (8). The valve member (49) is moved forward and backward by an actuator (51). When the valve member (49) is seated on the valve seat (50), the valve member (49) closes a pressure path (35). In this state, the operation of amplifying a braking force by the power brake device is not performed. The brake system may be incorporated into a vehicle with a regenerative brake device. The operation of amplifying a braking force by the power brake device can be interrupted. Therefore, the brake system produces a braking force optimal for a current loading state of a vehicle. The braking force amplifying operation of the power brake device can be stopped until the regenerative brake device produces a large regenerative braking force. Therefore, the regenerative braking force can be effectively used.

Abstract: An antiskid brake control system includes a supply passageway (16) bypassing a pressure-compensated flow control valve (13), and a check valve (22), which allows flow of brake fluid only toward a wheel cylinder, or a check valve (23), which allows flow of brake fluid only away from the wheel cylinder, is provided inside the supply passageway (16) and arranged in series with an orifice (15). Accordingly, antiskid brake control is such that either slow and fast pressurization modes, a fast depressurization mode and a holding mode or slow and fast depressurization modes, a fast pressurization mode and a holding mode are established. A sudden fluctuation in braking hydraulic pressure can be suppressed by establishing the holding mode when there is a transition from the fast depressurization mode to the fast pressurization mode or from the fast pressurization mode to the fast depressurization mode.

Abstract: A brake booster for holding the braking action even if the brake pedal is released. The booster has a low pressure chamber and a variable pressure chamber with a diaphragm therebetween for moving the output shaft to the brake cylinder. A valve mechanism mechanically controlled by the brake pedal switches a communication passage between the low and variable pressure chambers and an atmospheric pressure passage from the variable pressure chamber to the exterior. A first solenoid valve can close the communication passage between the low and variable pressure chambers irrespective of the brake pedal position so as to hold the braking. A second solenoid valve can control a passage between the variable pressure chamber and the low pressure source so that the braking release can be gently effected.

Abstract: In a conventional solenoid valve, a solenoid coil is disposed on a spool of a non-magnetic material, which forms a magnetic path therefor. By contrast, according to the invention, a sleeve-shaped guide which is formed as part of a spacer of a magnetic material is fitted into the spool and a plunger is slidably fitted into the guide, so that the plunger and the spacer define part of the magnetic path for the solenoid, thus allowing an improved magnetic path to be defined.

Abstract: A vacuum-type brake booster device for automotive use having a shape such that the mounting of the booster device and surrounding components inside the engine compartment of the vehicle is markedly eased. The shell of the booster device, and hence the diaphragm contained therein, has the shape in the plane of the diaphragm of a circle having a peripheral segment thereof removed. This causes the effective center of the diaphragm to be shifted from the center of the circle. The input and output shafts and the master cylinder are mounted on the shell aligned with the offset effective center of the diaphragm.

Abstract: A parking maintaining apparatus includes a solenoid-operated open/close valve which opens or closes a constant pressure passage providing a communication between a valve mechanism and a constant pressure chamber of a brake booster. A relief valve is provided which relieves a pressure within the constant pressure passage into the constant pressure chamber when such pressure exceeds a given value. The provision of the relief valve allows the pressure within a variable pressure chamber to be maintained at or below the given value through the valve mechanism under a parking maintaining condition, whereby the pressure within the variable pressure chamber can be rapidly displaced as the parking maintaining condition is to be terminated, thus eliminating a partly braked condition.

Abstract: A relay valve is operatively disposed between a pressurized air source and a work chamber of a brake booster. The relay valve has a pilot chamber so that the relay valve can feed the work chamber with a pressurized air, the pressure of which corresponding to that of a pressure applied to the pilot chamber. Electromagnetic valves are arranged to selectively connect the pilot chamber with the pressurized air source and the atmosphere. The valves are so controlled by an electronic control unit that the pilot chamber is supplied with pressurized air the pressure of which being determined in accordance with a brake pedal force applied from a brake pedal to an input means of the booster.

Abstract: An electromagnetically operated mechanism produces an unstable first controlled pressure which, under a given condition, is saturated quickly to a degree slightly lower than a target value determined in accordance with an information signal issued from a brake pedal force detecting device. A servo-motor type actuator produces a stable second controlled pressure which, under a given condition, is saturated slowly to the target value. A control mechanism applies only the first controlled pressure to a work chamber of a pneumatic brake booster when the first controlled pressure is higher than the second controlled pressure, and applies only the second controlled pressure to the work chamber after the second controlled pressure becomes higher than the first controlled pressure.

Abstract: A brake booster includes a solenoid valve which enables the opening or closing of a passage which provides a communication between a constant and a variable pressure chamber through a valve mechanism. The invention utilizes an empty space left within the constant pressure chamber for disposing a solenoid valve therein. The solenoid valve is mounted on a valve body in a manner to utilize the entry space efficiently to allow the solenoid valve to be mounted on the valve body without increasing the axial size of the brake booster.

Abstract: A brake power servo booster in which a power piston is slidably disposed in a shell, a master cylinder is connected to the brake pedal side of the shell, an input shaft is used to actuate a valve mechanism in order to generate a pressure difference between the forward and backward sides of the power piston, an output shaft is used to connect the power piston and a piston contained in the master cylinder, and a stopper member is provided in the housing of the master cylinder for limiting the retreat position of the input shaft.

Abstract: A flow control device for controlling the flow rate of fluid utilizes a stepping motor. A translating mechanism translates the rotation of the stepping motor into a rectilinear movement which causes a valve to move in either forward or backward direction, thereby controlling a clearance formed between the valve and its associated valve seat. A channel area is controlled in this manner, and a flow control over an extensive range from a minimal to maximal flow is achieved with a high accuracy and improved response.

Abstract: A brake power servo booster including a stationary stop provided on the cylindrical projection of a rear shell, and a movable stop provided on an input shaft connected between a brake pedal and a valve mechanism, and operationally associated with the stationary stop to restrict the retracted position of the input shaft. An intermediate stop member is slidably provided in the cylindrical projection, and has its retraction restricted by the stationary stop. The input shaft extends slidably through the intermediate stop member. The movable stop is adapted for abutment on the intermediate stop member to restrict the retracted position of the input shaft.

Abstract: A brake power servo booster, in which a fluid pressure difference is generated between opposite sides of a power piston, is provided with a wedge shaped member which is forced by the power piston between the wedge shaped recess of the members of an output shaft. When the wedge shaped member is forced into the recess by the piston the distance between the members of the output shaft is enlarged.