Nissin Kogyo Kabushiki Kaisha

Nisshin Kogyo Kabushiki Kaisha

Honda Giken Kogyo Kabushiki Kaisha

Nissan Kogyo Kabushiki Kaisha

Nissin Kogyo Kabushikia Kaisha

Hiroo Takeuchi

Nobuaki Hachiro

Yoshihisa Miyazaki

Tadao Nakagawa

Kazuo Miyazaki

Kimio Koyano

Itaru Hirayama

Hideaki Miyake

Yoshito Hanazato

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. A pressure regulatng spring is also received in the valve housing for biasing the pressure receiving piston away from the valve member. The valve housing comprises a first half part having the inlet and integral with the master cylinder, and a second half part having the outlet and screwed to the first half part. The second half part has a valve cylinder fitted into its opening adjacent the first half part. A valve cylinder houses the valve member and the valve spring loaded between the valve member and the valve cylinder.

Master cylinder-reducing valve assembly

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.

Disc brake device

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.

Assembly of vacuum booster and master cylinder

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.

Vacuum booster device

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.

Vacuum source device for vacuum booster for vehicles

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. When vacuum pressure is stored in the first working chamber, the peripheral portion of the through-hole of the diaphragm is resiliently pushed to the disc portion of the booster piston by the elastic member, thereby reliably closing the through-hole of the diaphragm and preventing unnecessary leakage of the vacuum pressure from the first working chamber to the second working chamber.

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. Seal means are provided to through-holes of the disc portion through which the tie rods extend. The booster piston is divided into the central boss portion having a flange formed around its other circumference and the disc portion placed in contact with the rear surface of the flange, and a retainer member for clamping the disc portion and the inner circumferential bead of the diaphragm in cooperation with the flange is fixed to the outer circumference of the central boss portion.

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.

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.

Vacuum type brake booster device for vehicular use

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. A retainer plate for supporting one end of the return spring abuts against the front wall of the booster shell to prevent the vacuum deformation thereof and is secured to the tie rod so that the resilient force of the spring is shared by the tie rod to avoid any excessive loading on the booster shell.

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.

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.

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.

Negative pressure booster

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. Preferably, the booster shell and the plain bearing are integrally formed of a synthetic resin, and the cylindrical valve body is formed of a synthetic resin of higher hardness than that of the plain bearing.

Differential pressure operated servo boosters

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. Between the cup support and the forward piston portion there is defined an annular passage in communication with a communication passage which is formed in the outer peripheral surface of the forward piston portion and communicates with the supply port. A resilient piston cup is directly carried on the forward face of the cup support for controlling communication between the relief port and the hydraulic chamber in accordance with the axial sliding movement of the piston in the cylinder bore.

Growing community of inventors

Asashina, Japan

Hiroo Takeuchi