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 disc brake device including a piston, an automatic adjuster and a sleeve piston within the cylinder of a caliper body, wherein braking and automatic braking-gap adjustment are achieved by a hydraulic input, and said piston is pushed by a mechanical input through said sleeve piston and said automatic adjuster for braking.

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 source device of vacuum booster is disclosed. The device includes an air ejector having an air inlet communicated with the atmosphere, an air outlet connected to a vacuum pick-up port opening to the portion of the intake system of an internal combustion engine downstream of a throttle valve, and a pressure reduction chamber connected to a vacuum chamber of the vacuum booster. A by-pass passage connecting between the vacuum pick-up port and the vacuum chamber of the vacuum booster by detouring the diffuser of the air ejector imposes a smaller flow resistance than the diffuser. A first check valve is disposed in the by-pass passage, while a second check valve is disposed between the by-pass passage and the vacuum chamber.

Abstract: The diaphragm of a vacuum booster device is normally placed in intimate contact with the disc portion of the booster piston due to the pressure difference between the first and second working chambers. The diaphragm has through-holes which the tie rods penetrate, and the peripheral portion of each through-hole is resiliently pushed to the disc portion of the booster piston by means of an elastic member. When the booster piston is manually operated while no vacuum pressure is stored in the first working chamber, the air in the first working chamber compressed by the advance of the booster piston is discharged into the second working chamber through the through-hole of the diaphragm, thus insuring smooth manual operation of the booster piston.

Abstract: A vacuum booster device which comprises a booster shell; a booster piston axially slidably accommodated in the booster shell and having a central boss portion and a disc portion around the outer circumference of the boss portion; and a diaphragm superposed on the rear surface of the disc portion and having an inner circumferential bead fitted to the central boss portion of the booster piston and an outer circumferential bead fitted to the circumferential wall of the booster shell. The booster piston and the diaphragm cooperate with each other to divide the interior of the booster shell into a front side first working chamber communicated with a vacuum supply source and a rear side second working chamber selectively communicated with the first working chamber or the atmosphere via a control valve operatively connected to an input member. The front and rear walls of the booster shell are connected to each other by tie rods extending through the disc portion of the booster piston and the diaphragm.

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 negative pressure booster wherein a brake master cylinder of an automobile is boosted and operated under negative pressure. The booster comprises a booster shell, a booster piston to divide the interior of the booster shell into a first and second actuator chambers, a valve cylinder, a valve piston received in the valve cylinder and a resilient valve body. During the retraction of the valve piston, the retracting force thereof is supported on the resilient valve body so that as the retracting force increases, the gap between the first valve seat and the valve portion increases.

Abstract: An improved differential pressure operated servo-booster herein disclosed comprises a booster shell, a forward first fluid chamber and a rearward second fluid chamber defined by a booster piston within the booster shell and normally in communication with a vacuum source, a cylindrical valve body integrally extended at the rearward surface of the booster piston and slidably supported on the rearward side wall of the booster shell through a plain bearing, a control valve received within the cylindrical valve body to permit the second fluid chamber to selectively communicate with the first fluid chamber or atmosphere, and an input rod disposed with the cylindrical valve body and operatively connected to the control valve, the plain bearing being formed integral with the rearward side wall of the booster shell in a seamless fashion.

Abstract: A master cylinder for actuating a hydraulic cylinder for a hydraulic brake or clutch. The master cylinder includes a cylinder body having a cylinder bore defined therein. The cylinder bore is in communication with an oil tank by way of a supply port and a relief port formed through the wall of the cylinder bore in axially spaced relation from each other. A piston is slidably received in the cylinder bore to define a hydraulic chamber forwardly thereof and comprises a pair of forward and rear piston portions axially spaced apart from each other with an annular seal member disposed therebetween. A cup support is integrally formed with the forward piston portion forwardly thereof and has a radially outer peripheral surface facing the inner peripheral surface of the cylinder bore with an annular clearance formed therebetween.

Abstract: A negative pressure booster wherein a brake master cylinder of an automobile is boosted and operated under negative pressure. The booster comprises a booster shell, a booster piston to divide the interior of the booster shell into a first and second operating chambers, a valve cylinder, a valve piston received in the valve cylinder and a reaction piston. The sliding stroke of the reaction piston is regulated to be smaller than the sliding stroke of the valve piston so that even if the valve piston is largely retracted, the amount of inflation and deformation of the resilient piston may be minimized.

Abstract: A vacuum type brake booster device including an input rod with an adjustable stop mechanism for enabling the input rod to have such a normal, full-retracted position as to hold the booster control valve in a neutral position to keep the second working chamber of the booster out of communication with the first working chamber thereof as well as with the atmosphere while holding the booster output rod in direct abutting engagement with the brake master cylinder piston. There is no delay in operation of the brake master cylinder when the brake pedal is depressed.

Abstract: On the wall of a booster shell which defines a vacuum chamber, a nonreturn-valve casing is formed in two halves. One casing half is formed integral with the wall of the booster shell and the other casing half is rotatably fitted to the former. With the first casing half formed in effect as a part of the wall of the booster shell, there is no leakage of vacuum from the booster shell to the exterior thereof. The second casing half has an L-shaped connector pipe formed integral therewith for connection with a vacuum line and the bent tip portion of the L-shaped connector pipe can be set in any radial direction simply by adjusting the angular position of the second casing half relative to the first.

Abstract: A device comprising two oil reservoir tanks communicating with the two respective oil-hydraulic chambers of a tandem type master cylinder and also with each other through an upper and a lower interconnecting oil passage. One of the two tanks has a top opening for oil filling use and normally closed with a vented cap while the other tank is closed at the top and provided therein with an oil level detector means which comprises a stationary reed switch connected with an appropriate external alarm circuit and a permanent magnet vertically movable with the oil level in the tank to close the reed switch as the volume of oil stored is reduced to a predetermined minimum. With the device, even if one of the two oil-hydraulic lines connected with the master cylinder fails to function due to oil leakage, the other line can properly function without any pressure failure as, in the associated tank, a predetermined minimum volume of oil remains on account of the height of the lower oil passage.

Abstract: A device usable in a brake system including two independent hydraulic lines extending from a dual brake master cylinder to front and rear wheel brakes, respectively. The device is arranged across the two hydraulic lines midway thereof to serve the purposes of adjusting the fluid pressure ratio between the front and rear wheel brakes with a change in ratio of the vehicle load bearing on the front wheels to that on the rear wheels thereby to maximize the overall braking efficiency particularly in hard braking operations and of enabling the brake system to operate even with some fluid leakage, possibly occurring in either of the two hydraulic lines, to brake the vehicle effectively enough while at the same time warning the driver of the fluid trouble. The essential component parts, including a number of cooperating pistons and a valve associated therewith, are accommodated in a single cylinder casing and this structure renders the whole device particularly compact in size and simple in construction.