JPS60226351A - Negative pressure operating type brake power booster with master cylinder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a negative pressure actuated brake power booster equipped with a mask cylinder, and particularly relates to a brake power booster of a negative pressure operated type equipped with a mask cylinder. a mask cylinder connected to the gas cylinder; a movable wall provided within the booster housing and sealed to the booster housing;
A control system that operates together with this movable wall and houses a valve mechanism inside.
Ill element housing, a valve piston which is slidable by means of a piston rod and a stepped butsch rod piston of the mask cylinder which is actuated via a reaction device by the end of the valve piston on the side of the mask cylinder; The present invention relates to a negative pressure operated brake power booster with a mask cylinder and a bushing rod for operating the brake power booster.

"Technical background of the invention and its problems" In this type of brake unit, when the brake is activated when the negative pressure operated brake power booster fails,
a piston roller pivoted on the brake pedal pushes the valve piston of the valve mechanism in the control element housing against a reaction device, which reaction device acts together with the bushing rod piston against the bushing rod;
Working together with the control element housing and the movable wall, a brake pressure will be created in the pressure chamber of the mask cylinder. However, in such a general configuration, if a failure occurs in the negative pressure operated brake power booster, it is necessary to press the brake pedal relatively hard before brake pressure is built up, and the piston in the mask cylinder also needs to be depressed. The effective cross-sectional area of the brake pedal remains large, and the piston must be moved only by the depression force without any external auxiliary force, so the brake pedal depression force after the depression has been exceeded is relatively small. There is a major problem with this.

Furthermore, a tandem master cylinder of a hydraulic brake system (German Published Patent Application No. 246,529) is known, and the first piston of this tandem master cylinder is actuable by an output member of a pedal-operated brake power booster. The brake power booster has a movable wall that creates a fluid pressure difference, and the brake power booster is equipped with a device for reducing the required pedal force when the brake power booster loses its operating pressure. For that purpose, the device has a valve which is biased toward the open position and which is switched to the closed position by the actuation pressure of the brake power booster, which valve establishes the connection between the reservoir and the pressure chamber. It is something to control. For this purpose,
Brake units of this type are equipped with an auxiliary piston, which has a larger diameter than the first piston. The auxiliary piston is arranged between the output member of the brake power booster and the first piston of the mask cylinder,
The pressure chamber is formed by a control pressure chamber located between the auxiliary piston and the first piston, that is, a chamber separated from the first pressure chamber and the second pressure chamber of the master cylinder. However, in this conventional tandem master cylinder, when the negative pressure is removed, the pedal hangs down relatively significantly and the first piston and the auxiliary piston abut each other. They have the disadvantage of moving together as a mechanical unit.

``Object of the Invention'' The object of the present invention is to eliminate the disadvantages of the known brake power booster with a mask cylinder, and to reduce the amount of pedal depression as much as possible when the operating pressure of the booster is available. To provide a negative pressure actuated brake power booster with a mask cylinder that can increase the pressure transmission ratio by switching to a mask cylinder with a small effective screw area when the cylinder is not available.

"Summary of the Invention and Effects thereof" According to the present invention, the above-mentioned object is achieved in that the bushing rod is connected to the control element housing via the cap fixed to the control element housing, and that there is an axis between the cap and the bushing rod. directional play is provided by which the bushing rod is movable relative to the control element housing in the longitudinal direction of the housing, and when the bushing rod is moved relative to the control element housing, a cap acting with the sleeve causes the first valve is actuated, and this first valve connects the large diameter of the bush rod piston via a second valve which closes a passage in the bush rod piston and an inlet port located between the socket pipe and the annular chamber of the reservoir. This is achieved by connecting the annular chamber located behind the step to the pressure chamber of the first circuit.

For the above-mentioned purpose, the back-up plate is preferably formed with a central opening and is provided with a radially extending stud, which stud engages an opening in the sleeve surrounding the stem of the front piston. are combined. This opening is sized such that the sleeve is movable a distance that the backup plate is longitudinally relative to the sleeve and such that the pedal end of the sleeve abuts against the cap of the control element housing. . The sleeve, which moves coaxially with the stem of the bush rod piston, is preferably provided with a slidable friction ring at its end facing the mask cylinder, which friction ring operates in conjunction with the annular valve. This valve controls a pressure fluid passage leading from the reservoir through an inlet port to an annular chamber located behind the bush rod piston.

The annular chamber is partly connected via an inlet passage to a chamber arranged in front of the bush rod piston, which inlet passage is arranged in the housing of the mask cylinder. The pressure fluid passage led through the inlet passage is controlled by a valve provided in the piston cap during brake application.

In a preferred embodiment, a passage is formed in the stem of the bush rod piston, and this passage is connected to the pressure chamber. The outlet of the passage on the outer surface of the stem is
In the brake release position, it is closed by the mask cylinder side end of the sleeve surrounding the stem, and in the brake release position, it is released by the sleeve if the booster fails.

The backup plate is preferably supported on the head member of the mask cylinder via a spring, the spring biasing the sleeve surrounding the stem of the bush rod piston through the backup plate against the cap surrounding the reaction device. ing.

According to this invention, the bushing rod acting on the bushing rod piston passes through an opening provided in the bottom of the cap, and the bushing rod is provided with a bushing plate at its end on the pedal side. This bushing plate works in conjunction with a reaction device held on the cylindrical inner surface of the cap.

In order to ensure normal opening and closing operations of the control sliding valve, play is provided between the mask cylinder side surface of the bushing plate and the lateral inner surface of the cap when the brake is released. This corresponds to the opening stroke of a valve consisting of at least the passage in the stem and the mask cylinder side end of the sleeve.

In a particularly preferred embodiment from a production technology point of view, the cap is provided with a radially outwardly extending bent rim which supports a spring device on the side of the control element housing and which acts together with the sleeve. The back-up plate is generally cup-shaped and has a spring interposed between the bottom of the back-up plate and a stop located at the end of the sleeve on the control element housing side. Backup brake that works with sleeve
- is preferably provided with a central opening in its center, through which the sleeve passes, and the back-up plate acts in conjunction with a retaining ring provided at the stem end of the bushing front piston on the side of the control element housing. , this retaining ring will pull on the backup plate when the bushing piston moves relative to the sleeve.

"Embodiment of the Invention" An embodiment of the invention will be described below with reference to FIGS. 1 to 3.

1 in FIG. 1 indicates a booster housing of a brake power booster. The booster housing 1 consists of two housing shells 15.16, which are connected to each other at a connection 14. The internal space of the booster housing 1 is divided into a negative pressure chamber 2 and a power chamber 3 by a diaphragm holder 5. Negative pressure chamber 2 is connected to a negative pressure source via a connection port. A rolling diaphragm 4 is glued to the diaphragm holder 5 and a control element housing 7 is also provided.

This control element housing 7 has a cylindrical shape and is connected to the diaphragm holder 5 and the rolling diaphragm 4. The outer peripheral edge of the rolling diaphragm 4 is the connection part 1
4 in an airtight manner, and its inner peripheral edge surrounds the neck portion 17 of the diaphragm holder 5.
The neck 17 is then tightened against the control element housing 7.

The cylindrical part 7' of the control element housing 7 projects from the booster housing 1 and is connected to the sliding guide ring 18.
The power chamber 3 is kept airtight from the outside through the.

A control rod is arranged slidably in the axial direction in the control element housing 7 . This control rod consists of a piston rod 11 and a valve piston 9, and the control rod is connected to the brake pedal of the automobile via a clevis (not shown).

Furthermore, within the control element housing 7 there is a valve mechanism 8.13°19.
is accommodated. This valve mechanism 8.13.degree. 19 is actuated by the valve piston 9 and thereby controls the differential pressure created between the negative pressure chamber 2 and the power chamber 3 via the passage 19.20.

A cap 21 is provided at a portion of the control element housing 7 located within the negative pressure chamber 2, and a reaction force device f[10 is held within this cap 21.

The reaction device 10 has a reaction lever or a reaction disk made of a resilient material such as rubber. Furthermore, the cap 21 guides a bushing plate 22 of a bushing rod 12, which actuates a brake master cylinder 23. This master ring 23 is fixed to the front end face of the housing sill 16, which forms part of the booster housing 1; in order to restore the diaphragm holder 5 with the diaphragm 4 as well as the control element housing 7; A spring device 6 is arranged between the cap 21 of the control element housing 7 and the housing shell 16 of the booster housing 1 .

Inside the mask cylinder 23, there is a floating piston 2.
4 and a bush rod piston 25 are arranged.

The bushed piston 25 is configured as a stepped piston. The bushing rod piston 25 is inserted into a sleeve 27, and the sleeve 27 is connected to a controllll1 sliding valve, which is a first valve, which is disposed slidably in the longitudinal direction with respect to the stem 26 of the bushing rod piston 25. functions as An annular chamber 28 located behind the stepped portion of the bush rod piston 25 is connected to a reservoir (not shown) via an inlet port 31 and a socket pipe 30, which can be closed by a ring-shaped second valve 32.

A locking spring 33 is applied to the end face of the second valve facing the control element housing 7 , one end of which is supported by a head member 34 . This head member 34 has 77 mm and 11 cm of pouf.
(71) is closed, and an opening for inserting the sleeve 27 is formed in the center. A slidable friction ring 35 is provided at the end of the sleeve 27 on the mask cylinder side. This *m ring 35 is connected to the second valve 3 when the front piston 25 is in the initial position.
2 in the open position shown in FIGS. The annular chamber 28 connects to the filling chamber 3 via a passage 36.
It is connected to 7. Furthermore, the inlet passage 45.45=
The annular chamber 28 and a first pressure chamber 40 located in front of the bush front piston 25 are connected to each other.

In the illustrated rest position of the master cylinder 23, the two valves 38, 32, as well as the valve 39, are each open, providing fluid communication from the socket pipe 30 to the first pressure chamber 40 and the filling chamber 37. , and fluid communication from the socket pipe 41 to the second pressure chamber 42 is established. When brake application is initiated (with the brake booster in the second state), the piston rod 11 moves immediately so that the push rod 12 and the sleeve 27 move to the left almost simultaneously. The valve mechanism 8', 13, 194 allows air to flow into the power chamber 3, thereby causing the diaphragm 4
A movable wall 46 consisting of a diaphragm holder 5 and a diaphragm holder 5 is moved together with the control element housing 7 and the cap 21 in the actuation direction. The bush rod piston 25 and the sleeve 27 are moved simultaneously as described above, and the valves 38 and 39 close off the inlet boats 45.45'', 47 leading to the socket pipes 30 and 41, respectively, so that the first and second Brake pressure is built up in the pressure chambers 40 and 42. Since there is no relative movement between the front piston 25 and the slave 27, the passages 36, 36- also remain closed and from this the brake pressure is increased. The entire cross-sectional area of the Schrod piston 25 becomes effective.

In the event of a fault in the booster, the control element IsUsing 7
is initially held in the rest position when the brake pedal is depressed, i.e. when the piston rod 11 is moved, but the bushing rod 12 is moved in the operating direction, ie to the left. In the initial phase when the brake pressure is built up in the first and second pressure chambers 40 and 42, the sleeve 27
acts as a control slide valve so that passage 36 is removed from annular chamber 28.
36' to the filling chamber 37 (this filling chamber 37 is connected to the groove 48
The first pressure point 40 is in communication with the first pressure point 40 via. ) will be opened.

A further movement of the piston rod 11 in the direction of the arrow A (left) (beyond the play b between the bushing plate 22 and the cap 21) causes the control element housing 7 together with the movable wall 46 to absorb the force of the spring device 6. is moved against. Play b between backup plate 49 and sleeve 27
When the bushing rod piston 25 is exhausted, the sleeve 27 together with the bushing rod piston 25 is also moved in the direction indicated by arrow A. In such a phase of operation, due to the movement of the sleeve 27, the locking spring 33 is released by the friction ring 35 connected to the sleeve and the second valve 32
This second valve 32 closes the inlet boat 31 so that it can be moved to the left. In the direction of the arrow, the piston rod 11, the valve 13, the bushing rod 12 and the sleeve 2
7 further (by moving two times, Busoshrod piston 25
tcL in this case will function as a plunger piston with an effective cross-sectional area denoted by C, and in the PRE-1 key circuit (corresponding to the applied pedal force)
A relatively high hydraulic pressure is built up. The pressures across the shoulder 29 of the bush rod piston 25 are equal during this phase of braking.

During this time, the first cap 50 of the valve 38 does not function. When the pedal is returned, i.e. piston rod 1
1 moves in the opposite direction to the direction indicated by arrow A, pressure liquid flows from the annular chamber 28 located behind the shoulder 29 into the first pressure cap 40 through the first cap 50; This pressure liquid is then returned to the reservoir via the passage 45, 45' and the socket pipe 30. In the brake release position, the second valve 32 is opened again and the control slide valve (comprised of sleeve 27, stem 26 and passage 36') is closed.

In a normal booster, the diameter of the dandem master cylinder is set in consideration of power booster failure.

In the subject matter of this invention, when the system is normal,
The diameter of the sleeve 27 is determined by the cross-sectional area of the sleeve 27 or simply by the depression pressure, and the diameter of the sleeve 27 is determined so that the amount of pedal depression can be reduced as much as possible by increasing the diameter of the bush rod piston 25 relative to the sleeve 27. . In the booster of this invention, the reduction in the amount of pedal depression and the increase in the braking effect are caused by the fact that when the booster fails, the effective cross-sectional area of the piston changes from a to sleeve 2.
This can be obtained by the characteristic that the cross-sectional area is reduced to 7. Furthermore, the booster of the present invention has the advantage that it can be installed in place of a conventional booster without requiring any equivalent changes to either the brake system or the vehicle.

In FIG. 4, the floating piston 24' has a spring pot 60 with five screws and a spring 61.
The floating piston 24- is provided as an alternative to the 70-ring piston 24 connected to the plunger 24 of the bushing rod piston 25 in the mask cylinder 23 shown in FIG. According to such a modification, the pressure fluid in the annular chamber 28 flows back smoothly during the return stroke, and the pressure difference not only in the filling chamber 37- but also in the first and second pressure chambers 40' and 42- is simultaneously reduced. and can be easily balanced.

[Brief explanation of the drawing]

FIGS. 1 to 3 show one embodiment of the present invention.
The figure is a cross-sectional view of a negative pressure operated brake power booster equipped with a tandem master cylinder, Figure 2 is an enlarged cross-sectional view of the annular valve in Figure 1, and Figure 3 shows the backup plate in Figure 1 together with the sleeve. FIG. 4 is a partially sectional view of a tandem master cylinder showing a modification of the present invention. 1... Booster housing, 2... Negative pressure chamber, 3...
・Power chamber, 4...Rolling diaphragm, 5...
-Diaphragm holder, 6...spring device, 7.
7'... Control element housing, 8.13.19... Valve mechanism, 9... Valve bismine,
10... Reaction force device, 11... Piston rond, 12
... Bushing rod, 19.20.36.36-... Passage, 21... Cap, 22... Bushing plate, 23... Mask cylinder, 24... 70-Tinging piston, 25...
... Butsch rod piston, 26 ... Stem, 27
... Sleeve, 28 ... Annular chamber, 30 ... Socket pipe, 31 ... Inlet port, 32 ... Second valve,
35...Friction ring, 4...Backup plate, 5o...Piston plate, 54...Rim, 5
5.57...Retaining ring. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] 1. A mask cylinder connected to one housing shell constituting a booster housing, a movable wall provided within the booster housing in a sealed manner with respect to the booster housing, and together with this movable wall. a control element housing which is actuated and accommodates a valve mechanism therein, a valve piston which is slidable by a piston rod and which is actuated by the mask cylinder end of the valve piston via a reaction force device and whose part is In a negative pressure actuated brake power booster, the bushing rod is connected to the control element housing via a cap fixed to the control element housing. Ren-!r4/1
71. %S J-pjetLji order t1 Leet, Leh f,
an axial play is provided between the bushing rod and the control element housing, which play allows the bushing rod to move relative to the control element housing in the longitudinal direction of the housing;
When the bushing rod is moved relative to the control element housing, the first
A valve is actuated, the first valve opening the large part of the buttschront piston via a second valve that closes the passage in the buttschrod piston and the inlet boat arranged between the socket pipe and the annular chamber of the reservoir. A negative pressure operated brake power booster in a mask cylinder position, characterized in that an annular chamber arranged at the rear of the stepped portion is connected to a pressure chamber of a first circuit. 2. A back-up play i~ comprising a stud having an opening in the center and extending in the radial direction, the stud being engaged with the opening disposed in the sleeve 1, and this sleeve being connected to the bushing front piston. surrounding the stem, the opening in the sleeve is sized such that the backup plate is longitudinally movable a distance relative to the sleeve, and the pedal end of the sleeve is connected to the cap of the control element housing. 2. A mask cylinder negative pressure actuated brake power booster according to claim 1, wherein the brake power booster is in abutment against a mask cylinder. 3. The sleeve, movable coaxially with the stem of the bush rod piston, is provided with a friction ring slidable at its end facing the mask cylinder and cooperating with an annular second valve; controls a pressure fluid passage leading from the reservoir through an inlet port to an annular chamber located aft of the bush rod piston, the annular chamber having a portion of the mask cylinder located in front of the bush rod piston. Claim M1 or Claim 2, characterized in that the pressurized liquid passage is connected via an inlet passage arranged in the housing of the invention, and when the brake is actuated, the pressure liquid passage is controlled by a valve equipped with a piston carburetor. Negative pressure operated brake power booster with master cylinder as described. 4. The stem of the bush rod piston is provided with a passage connected to the pressure chamber, and the outlet on the outer surface of the stem is closed by the mask cylinder side end of the sleeve surrounding the stem when the brake is in the release position. Claim 1 characterized in that it is released by a sleeve in the event of a failure of the booster while in the actuated position of the brake.
3. The mask cylinder vacuum actuated brake power booster according to any one of Items 3 to 3. 5. The backup plate is supported by the head member located on the pedal side of the mask cylinder via a spring, and this spring connects the sleeve surrounding the stem of the butschront piston via the backup plate to the cap surrounding the reaction force device. A mask cylinder negative pressure actuated brake power booster according to any one of claims 1 to 4, characterized in that the brake power booster is actuated by negative pressure at a mask cylinder position. 6. The bushing rod that operates the bushing rod piston passes through an opening provided at the bottom of the cap, and a bushing plate is provided at the end on the pedal side, and this bushing plate is held by the cylindrical inner surface of the cap. A negative pressure operated brake power booster with a mask cylinder according to any one of claims 1 to 5, characterized in that the booster operates together with a reaction force device. 7. Play is formed between the mask cylinder side side of the bushing plate and the inner surface of the bottom of the cap in the brake release position, and this play is caused by the passage extending through the stem and the mask cylinder side end of the sleeve. The mask cylinder position negative pressure actuated brake power booster according to any one of claims 1 to 6, characterized in that the mask cylinder position corresponds at least to the opening stroke of a valve constituted by . 8. The cap is formed with a radially outwardly curved rim, which rim supports the end of the spring device on the side of the control element housing.
The mask cylinder negative pressure operated brake power booster according to any one of items 7 to 7. 9. A patent characterized in that the backup plate that operates together with the sleeve has a substantially cup shape, and a spring is interposed between the bottom of the backup plate and a stop located at the end of the sleeve on the mask cylinder side. A mask cylinder negative pressure operated brake power booster according to any one of claims 1 to 8. 10. The back-up plate, which works with the sleeve, has a central opening in the center of its bottom, through which the sleeve passes, and when the bushing front piston is moved in the actuating direction relative to the sleeve, the stud is inserted into the control element housing. According to any one of claims 1 to 9, characterized in that, in conjunction with a stop provided at the end of the side bushing rod piston, this stop tensions the back-up plate. Mask cylinder negative pressure operated brake power booster.