JPS5975856A - Brake booster - Google Patents

Abstract

PURPOSE:To facilitate mounting a booster onto a wheel by forming each outer peripheral part of a front shell, rear shell, and a power piston in the state retreated to a brake pedal side rather than the center part. CONSTITUTION:A conical concaved part 45 is formed on the axis part of a rear shell 1b, and the top edge part of a master cylinder 2 is accommodated into said concaved part 45. Each shape of a power piston 4 and the front shell 1a is set along the sectional shape of the rear shell 1b. That is, each outer peripheral part of the power piston 4 and the front shell 1a is formed to be retreated towards a brake pedal side (right on the figure) rather than the center part. Also the reservoir 46 of the master cylinder 2 is installed in the retreated state to a position close to a chassis 3. Since a space is formed at the front of the outer peripheral part of the front shell 1a, a booster can be mounted onto the chassis without being interfered by other members.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a brake booster, and more particularly to a brake booster in which a master cylinder is disposed on the rear side of a booster mechanism including a power piston, that is, on the brake pedal side. .

In conventional brake boosters commonly used, a master cylinder is connected to the front side of the booster mechanism, and the shell of the booster mechanism is attached to the vehicle body. Brake booster ills with such a configuration are widely used because the valve mechanism that controls the opening and closing of the pressure fluid flow path in response to the forward and backward movement of the input shaft and the configuration of the flow path are relatively simple. However, since the shell was required to be rigid enough to support the master cylinder, there was a certain limit to the weight reduction of the brake booster by reducing the thickness of the shell.

On the other hand, in a brake booster in which a master cylinder is placed at the rear of the booster mechanism, the master cylinder can be attached to the vehicle body, so the shell simply has enough rigidity to withstand fluid pressure. All you have to do is pick grapes,
This is advantageous in reducing the weight of the brake booster. However, since the positions of the master cylinder, which has a relatively small radial dimension, and the large shell are reversed, there is a problem in that it is more difficult to install it on a vehicle than the above-mentioned general brake booster.

In view of these points, the present invention is designed to allow a brake booster in which a master cylinder is connected to the brake pedal side of the shell to be installed in a vehicle as easily as possible.

The present invention will be explained below with reference to the illustrated embodiment. In Fig. 1, (1) is a shell consisting of a front shell (la) and a palm shell (1b), and a master cylinder (2) is attached to the shaft of the rear shell (lb). The tips of the master cylinder (2) are connected, and the base of the master cylinder (2) is fixed to the vehicle body (3). A power piston (4) is provided within the shell (1) so as to be able to reciprocate along the axial direction of the shell (1),
The power piston (4) and the diaphragm (5) divide the inside of the shell (1) into a constant pressure chamber (6) on the front shell (la) side and a variable pressure chamber (7) on the palm shell (1b) side. There is. The tip of an output shaft (8) is connected and fixed to the shaft of the power piston (4) in an airtight manner, and the output shaft (8) is kept fluid-tight by a sealing member (9) and is connected to the mask. It is slidably passed through the housing (10) of the cylinder (2).

In the illustrated embodiment, the master cylinder (2) is configured as a two-system master cylinder, and a primary side piston (11) and a secondary side piston (12) are installed in the housing (1O). We are prepared. The output shaft (8) is connected to each piston (11), (12).
The output shaft (8) has pressure chambers (13) and (14) formed in front of each piston (IIL (12)) on the outer periphery of the output shaft (8). The left end surface of the rear aximin disk (15) is disposed opposite to the right end surface of the piston (11) on the primary side, and is integrally screwed to the output shaft (8).
The left end surface (16a) of the connecting member (16) forming a part of
) are disposed opposite to the right end surface of the reactor cylinder (15), thereby transferring the thrust of the power piston (4) to the master cylinder via the output shaft (8), the connecting member (16) and the reaction disk (15). There is a valve on the rear side of the output shaft (8) that is operated by the input shaft (20) and creates a pressure difference before and after the power piston (4). A mechanism (21) is provided. Above input shaft (20)
A cylindrical member (22) whose distal end is slidably fitted into the sleeve (10a) of the master cylinder (2), a connecting member (23) fixed to the distal end of this planar member, and It consists of an operating rod (24) with a spherical tip (24a) pivotally supported in the detail of the connecting member (23), and the cylindrical portion 8 (2
The stepped end face (22a) formed at the tip of 2) faces the right end face of the reaction disc (15), and the distal end of the operating rod (24) is linked to a brake pedal (not shown). In addition, a removal stopper (25) is provided between the recording sleeve member (22) and the connecting member (16), and the removal stopper (25) allows both to be moved relative to each other. are connected.

The valve mechanism (21) includes a first valve seat (30) formed on the inner periphery of the cylindrical member (22), and a connecting member ( 16) It is equipped with a second valve seat (31) formed at the end, and a valve body (32) seated on both valve seats (30) and (31) from the right side thereof, and this valve body (32) In the illustrated non-operating state, the first #Ml (3o) is seated by a spring (33) elastically loaded between the connecting member (23) of the input shaft (2o) and the valve body (32);
It is separated from the second valve seat (31) by a spring (34) loaded between the IEfC input IIQII (20) and the output shaft (8).

Then, the outer side of the sealing part between the valve body (32) and the first valve seat (30) is connected to the shaft part of the cylindrical member (22) and the connecting member (23).
is opened to the atmosphere through a passageway (35) formed in and a filter (36) disposed on the outside of the connecting member (23);
The inside of the seal between the valve body (32) and the second valve seat (31) is communicated with the constant pressure chamber (6) via a passageway (37) formed in the shaft portion of the exit shaft (8). In addition, a passage (38) formed in the connecting member (16) is located between the two seal portions.
The output shaft (8) is communicated with the variable pressure chamber (7) through a passageway (39) formed on the outer circumference of the output shaft (8). The above passage (39
), as shown in Fig. 2, has a plurality of grooves (
41), and a hollow shaft (41) is formed on the outer periphery of the hollow shaft (40).
42) into the groove (41).

The rear shell (1b) has a substantially U-shaped cross section and has a conical recess (45) in its shaft, and the tip of the master cylinder (2) is inserted into this recess (45). It is stored. The shapes of the power piston (4) and the front shell (la) are set in accordance with the cross-sectional shape of the rear shell (1b). The part is moved backward from the center part, that is, towards the brake pedal side, so that even if there is a tire house, engine, etc. on the front outer peripheral part of the front shell [la], it can be attached to the vehicle body without coming into contact with them. I have to.

Along with retracting the outer peripheral part of the shell (1), the reservoir (46) of the master cylinder (2) is also retracted to a position close to the vehicle body (3), and each pressure chamber (
Output boats (47) and (4) connected to 13) and (14)
8) are each connected to a connector (51) arranged on the outer periphery of the shell (1) via a conduit +49L (50),
Brake piping of each system (not shown) is connected to this connector (51). Please note that this connector (5
1) is connected to the master cylinder (
2) is connected and fixed to the housing (lO).

In addition, in Fig. 1, +53L (54) connects each piston (IIL T12) of the Marotar cylinder (2) to +5
5) are return springs that hold the power pistons (4) in the non-operating positions shown.

In the above bridge construction, in the non-operating state shown in the figure, the valve mechanism (2
Since the second valve seat (31) and the valve body (32) of 1) are separated from each other, the negative pressure is introduced into the constant pressure chamber (6) from the negative pressure inlet (not shown) provided in the front shell (1a). Output shaft (8)
The negative pressure introduced into the passageway (37) is applied to the gap between the second valve seat (31) and the valve body (32) and the passageway (38).
It is introduced into the variable pressure chamber (7) via L (39), so there is no pressure difference before and after the power piston (4).

When the brake pedal (not shown) is depressed from this state and the input shaft (20) moves to the left, the valve body (32) first moves to the second position.
Seated on the valve seat (31), the above-mentioned constant pressure chamber (6) and variable pressure chamber (
7), and the valve body (32) is removed from the first valve seat (30) by subsequently moving the input shaft (20) to the left. Then, the atmosphere passes through the filter (36) and the passageway (35).
, is introduced into the variable pressure chamber (7) through the gap between the valve body (32) and the first valve seat (30), and the passages (38) and (39), so that pressure is generated before and after the power piston (4). A difference is generated, which causes the power piston (4) to move to the left against the return spring (55).

When the power piston (4) moves to the left, its thrust is transferred to the primary side piston (1) of the master cylinder (2) via the output shaft (8) and the reaction disc (15).
1), and when this piston (11) moves to the left and generates brake fluid pressure in the pressure chamber (13), the secondary piston (12) also moves to the left and generates brake fluid pressure in the pressure chamber (13). (14) Generate brake fluid pressure within. And the brake fluid pressure generated in each pressure chamber (13), (14) is output boat +47L (48L conduit (49), (
50) and a connector (51), it is supplied to a wheel cylinder (not shown) for braking, as is well known in the art. Further, the brake reaction force generated on the piston (11) is transmitted to the brake pedal via the reaction disk (15) and the input shaft (20). In this case, it goes without saying that the rear aximine disc (15) functions substantially the same as the rear aximine disc used in the reaction force mechanism of a conventionally known brake booster.

Furthermore, if the depression force on the brake pedal is released from the braking state, the valve mechanism (21) switches to the state shown in the figure, so it is clear that the valve mechanism (21) returns to the non-operating state described above.

FIG. 3 shows another embodiment of the present invention, which differs from the embodiment described above mainly in that the reaction force mechanism and the valve mechanism (121) are disposed on the front side of the master cylinder (102). It's set.

In this embodiment, a valve body (160
), and the power piston (104) and the valve body (
160), these are integrally connected to each other. A valve mechanism (121') is provided in the valve body (160), and the first human power shaft (120a) of the input shaft (120) operates the valve mechanism (121).
is slidably passed through the cylindrical bolt (161),
A second valve seat (131) is provided at its tip, and a spherical tip (124a) of an operating rod (124) is pivotally connected to its end. In the illustrated non-operating state, the valve mechanism (121) connects a constant pressure chamber (106) and a variable pressure chamber (TO7) to a passage (162) formed in a valve body (160) and a closing member (121) attached to the valve body (160). 163) formed in the radial passage (164L valve body (132) and the second valve seat (1
31), a passage (165) formed in the valve body (160), and a passage (166) formed in the power piston (104).

On the other hand, when the input shaft (120) moves forward, the valve body (132) is seated on the second valve seat (131) and the constant pressure chamber (106)
At the same time as blocking the communication between the transformer chamber (107) and the pressure changing room (107), the air is filtered (167) and the closing member (163)
an axial passageway (168) formed at a position different from the radial passageway (164), a gap between the valve element (132) and the first valve seat (130) formed in the valve body (160), and the passageway (168); 165) and (166) to the transformation chamber (
107), thereby causing the power piston (1
04) A pressure difference is generated before and after.

Further, the output shaft (108) has a large diameter portion formed on its end side and is used as a primary side piston (111), and the inner peripheral surface of this output shaft (LO8) and a cylindrical shape are formed. The inner peripheral surface of the bolt (161) and the first human power shaft (120)
a) while maintaining liquid tightness between the reaction force transmitting member (17) and the outer layer surface of the
0) is slidably fitted, and this reaction force transmission member +170)
A space in front of the cylinder is used as a reaction force chamber (171) and is communicated with a pressure chamber (1114) in the master cylinder (102).

Further, the reaction force transmission member (170) and the output shaft (10
Normally, the spring (173) loaded between the retainer (172) attached to A required gap (6) is formed between the end face of the diameter portion and the end face of the diameter portion.

Also in this embodiment, a recess (145) is formed in the shaft portion of the rear shell (101b) so that the master cylinder (10
2) is housed in the recess (145), and the power piston (104) and front shell (101a) are also formed with their outer peripheries set back from the center toward the brake pedal. ing. On the other hand, in this embodiment, the depth of the four parts [145] is made shallow to reduce the storage space of the master cylinder (102).
Thereby, the brake piping (174), (175) of each system is directly connected to each output boat (147), (148) without going through the aforementioned connector (51).

The rest of the structure is substantially the same as that of the previous embodiment, and the main parts that are the same as or equivalent to those of the previous embodiment are designated by the same reference numerals as in FIG. 1 plus 100. It is shown with a .

In the above configuration, when the brake pedal is depressed and the input shaft (120) moves to the left, the valve mechanism (
121) is switched and the atmosphere is introduced into the variable pressure chamber +107), which causes the power piston (104), valve body (160), output shaft (108), and piston 1l
ll) is moved to the left and brake fluid pressure is generated in the pressure chamber (113), and accordingly, the piston +112) is moved to the left and brake fluid pressure is also generated in the pressure chamber (114). This pressure is introduced into the reaction force chamber (171).

At the beginning of braking when the brake fluid pressure introduced into the reaction force chamber (171) is low, the reaction force transmission member (170)
7a) is held in contact with the cylindrical bolt (161), and in this state, the reaction force transmitting member (170,)
There is a gap (
5) is maintained, and the brake fluid pressure is not transmitted to the input shaft (120) as a reaction force. and the reaction force chamber (
171) increases, and the reaction force transmission member (170) is moved against the splash (173) to the first human power shaft (120a).
), the brake fluid pressure is transmitted to the input shaft (120) as a reaction force for the first time.

As is clear from the above explanation, in the present invention, in a brake booster in which a master cylinder is arranged on the rear side of the booster mechanism, the outer periphery of the front shell is moved back toward the brake pedal, and the outer periphery of the front shell is Since a space is formed in the front part, a brake booster can be attached to the vehicle body even if there is a tire house or engine in that area, which is different from conventional brake boosters of this type. The effect is that it can be easily mounted on a vehicle compared to other devices.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of the present invention, and FIG.
FIG. 3 is a cross-sectional view taken along the line ■-■ in the figure, and FIG. 3 is a cross-sectional view showing another embodiment of the present invention. +IL [101)...Shell (1a), 1101a)--Front shell (ib),
(lOlb)...Rear shell +2L (102)...Master cylinder (4), +104)...Power piston f45), (145)...Four parts

Claims (1)

[Claims] The power piston is slidably disposed in a shell having a front shell and a rear shell, and a master cylinder located on the brake pedal side or connected to the palm shell. A brake booster characterized in that the outer peripheries of the power piston and the front shell are set back from the center line toward the brake pedal in accordance with the shape of the recess.