Abstract: A master cylinder-reducing valve assembly has a master cylinder and a reducing valve for transmitting output hydraulic pressure from the master cylinder to a rear wheel brake at a reduced level. The reducing valve includes a valve housing provided on the master cylinder and having an inlet communicating with the output port of the master cylinder and an outlet communicating with a rear wheel brake. A pressure receiving piston is slidably received in the valve housing to divide the interior of the housing into an input hydraulic chamber communicating with the inlet and an output hydraulic chamber communicating with the outlet. The pressure receiving piston has a communication bore connecting between the input and output hydraulic chambers. A valve member is disposed in the input hydraulic chamber to open and close the communication bore. A valve spring is received in the valve housing and biases the valve member toward the pressure receiving piston.

Abstract: A tandem master cylinder for an automobile disclosed herein includes a cylinder body having a cylinder bore, a first and a second pistons slidable in the cylinder bore and axially apart from each other, a first and a second power chambers defined, independently from each other, in the cylinder bore by the first and second pistons, and an auxiliary reservoir formed integrally with the cylinder body at its upper side adjacent the first power chamber. The auxiliary reservoir has a first and second reservoir chambers separated from each other by a partition and both connected with a main reservoir. The first power chamber is connected with the first reservoir chamber through a pair of first vent and supply ports. The second power chamber is connected with the second reservoir chamber through an oil passage which is formed in the cylinder body and which uprises in the direction from the latter to the former.

Abstract: A tandem master cylinder for an automobile disclosed herein includes a cylinder body having a cylinder bore, a first and a second pistons slidable in the cylinder bore and axially apart from each other, a first and a second power chambers defined, independently from each other, in the cylinder bore by the first and second pistons, and an auxiliary reservoir formed integrally with the cylinder body at its upper side adjacent the first power chamber. The auxiliary reservoir has a first and second reservoir chambers separated from each other by a partition and both connected with a main reservoir. The first power chamber is connected with the first reservoir chamber through a pair of first vent and supply ports. The second power chamber is connected with the second reservoir chamber through an oil passage which is formed in the cylinder body and which uprises in the direction from the latter to the former.

Abstract: A servo mechanism for a vehicle braking system comprises a pressure housing having a front shell 2 and a rear shell 3. A tie rod 43 passes through the front and rear shells 2 and 3, and also through a power piston 4 and diaphragm 5 within the pressure housing. One end of the tie rod carries a device to be actuated by the servo mechanism, while the other end of the tie rod is secured to a vehicle body. In order to provide a fluid-tight seal around the tie rod, a boot 53 is provided, having one end 53a secured to the tie rod 43, and the other end 53c secured within a hole 4a in the piston 4. A cylindrical securing member 54 clamps the respective end 53c of the boot 53 within the hole 4a in the piston 4, and also serves to clamp together the diaphragm 5 and piston 4, in the region of their respective holes 5a and 4a through which the tie rod 43 passes.

Abstract: An assembly of a vacuum booster device and a master cylinder comprising a booster shell composed of front and rear halves and a brake master cylinder body which are together combined by the aid of tie rods extending through the booster shell, and a booster piston accommodated in the shell so that the load on the booster shell is removed, any means for fastening the opposite edge portions of both the shell halves is eliminated and, accordingly, outside diameter of the shell is decreased without lowering its strength. Furthermore, retaining ring fitted in the tie rod effective in preventing the shell from separation enables both the constructing and separating works of the assembly easier.

Abstract: A vacuum type brake booster device comprising a booster shell, a booster piston accommodated in the booster shell, a piston diaphragm working together with the booster piston for dividing the booster shell into both front and rear working chambers, and tie rods extending through the piston and the diaphragm for connection of the front and rear walls of the booster shell. Circumferential positioning devices are arranged between the booster piston and piston diaphragm and between the piston diaphragm and booster shell, respectively, so that the piston can correctly be adapted to the shell. Accordingly, the booster piston can be operated freely from interference of the tie rods. Furthermore, the piston diaphragm can be prevented from unnecessary forces due to the pressure difference between both the working chambers by the aid of thin-wall portions arranged in the piston diaphragm.

Abstract: A vacuum booster device which is mainly used to operate a master cylinder for hydraulic brakes or the like of automobiles. The device is so constructed that the inner peripheral bead of the diaphragm disposed within the booster shell and the clamping band adapted to clamp the bead tightly are fitted in the annular fitting groove formed in the rear surface of the booster piston, a part of the inner peripheral bead is formed as a thin-walled elastic valve portion which is in close-contact with the inner surface of the annular fitting groove in a separable manner and which engages with the notched recess formed in the rear side wall of the fitting groove, and the relief is provided between the valve portion and the clamping band to allow deformation of the elastic valve portion. Thus, when the pressure within the first working chamber is increased, air can be discharged from the first working chamber to the second working chamber through a gap made in the relief region due to deformation of the valve portion.

Abstract: A vacuum type brake booster device comprising a first and a second working chambers defined in a booster shell by a booster piston, tie rods extending through the booster piston for connection of the front and rear walls of the booster shell so as to support loads on the booster shell, flexible bellows surrounding each of the tie rods and having opposite ends fixed respectively to the tie rod and the booster piston so that the inside of the bellows is communicated to the second working chamber, and an adjustable stop mechanism provided on an input rod for adjusting a retraction limit of the latter, whereby a control valve is held in a neutral position to keep the second working chamber out of communication with the first working chamber and the external atmosphere so that the bellows becomes expansive owing to a pressure difference between the working chambers for getting out of contact with the tie rod and, accordingly, for keeping the movement of the booster piston undisturbed.

Abstract: A vacuum type brake booster device is provided which comprises a booster shell of substantially elliptical shape in transverse cross section, a booster piston of similar shape as the booster shell and accommodated therein for axial reciprocating movement, and a diaphragm secured about the outer periphery thereof to the booster shell and about the inner periphery to the booster piston to divide the interior of the booster shell into a first working chamber in communication with a vacuum source and a second working chamber adapted to be selectively placed in communication with the first working chamber or the atmosphere by a switching valve. The diaphragm is also shaped substantially elliptically in transverse cross section, and includes a pair of opposite straight peripheral wall sections and a pair of opposite arcuate peripheral wall sections interconnecting the straight wall sections; the arcuate wall sections have a wall thickness greater than that of the straight wall sections.

Abstract: A highly durable and light-weighted vacuum type brake booster device including a booster shell, a booster piston axially slidably accommodated in the booster shell to divide the interior thereof into a first chamber communicating with a vacuum source and a second chamber adapted to be placed into selective communication through a control valve with the first chamber and the atmosphere, and an input rod operatively connected with the control valve for operating the latter to generate a pressure differential between the first and second chambers. The front and rear walls of the booster shell are connected with each other by means of tie rod(s) which extend(s) through the booster piston with a deformable seal member disposed therebetween. The booster piston is urged in a retracting direction by a return spring disposed in the first chamber.

Abstract: A vacuum type brake booster device comprising a booster shell, a booster piston accommodated in the booster shell, a piston diaphragm working together with the booster piston for dividing the booster shell into front and rear working chambers, and tie rods extending through the piston and the diaphragm for connection of the front and rear walls of the booster shell. The piston diaphragm is provided with reasonably arranged reinforcing beads integrally formed projected therewith for increasing the tensile rigidity of the diaphragm. Accordingly, the thrust force produced by the pressure difference between both the working chambers can be effectively transmitted from the piston diaphragm to the booster piston.

Abstract: A vacuum type brake booster device comprising a booster shell divided into front and rear halves, a booster piston accommodated in the booster shell, and tie rods extending through the booster piston for connection of the front and rear halves. The tie rod is firmly held upright at a prescribed position on the rear half wall by the combined action of a mounting support on the rear half wall, a stepped tie rod flange, an elastic sealing member disposed in said mounting support between the rear half wall and the stepped flange, a retainer ring inside the mounting support. Accordingly, the tie rod thus firmly secured to the rear half is readily aligned with and pass through a through hole in the front half to expedite the assembly of the front and rear halves and, in addition, use of the elastic sealing member contributes to the simplification of the construction.

Abstract: A hose with a one-way valve used in a brake actuating system for automobiles. A one-way valve unit is housed in a flexible hose for connecting a booster shell of a servomotor with an intake manifold of the internal combustion engine so as to prevent leakage of vacuum. A valve housing receives therein a valve member and a valve spring thereby forming the one-way valve unit. The housing further has a valve seat, a cylindrical guide portion and an annular seal projection of diameter larger than the guide portion. A fastening band is provided on the outer periphery of the hose to prevent movement of the one-way valve and is marked with a mounting direction of the hose.