JPH086661Y2 - Brake booster - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a brake booster, and in particular, it is mounted on a vehicle such as a bus and is used to reduce the collision noise in the brake booster as much as possible. Regarding valid ones.

[Conventional technology]

As a brake booster mounted on vehicles such as buses,
Some include a power cylinder that converts air pressure into liquid pressure and an oil cylinder. In this brake booster, the power piston in the power cylinder divides the cylinder into an air pressure chamber and an atmospheric pressure.
The power piston is provided with a push rod protruding toward the atmosphere chamber side, and the tip end of the push rod is engaged with the oil piston.

Further, in this brake booster, when the petal of the brake valve is stepped on, compressed air is supplied to the air pressure chamber in the power cylinder, so the power piston moves toward the oil cylinder and pushes out the oil piston. Has become. Then, by the movement of the oil piston, the liquid oil in the pressure chamber in the oil cylinder is pressure-fed into the wheel cylinder, and the braking action is performed.

As such a brake booster, there is one as shown in FIG. FIG. 4 is a sectional view of a main part of this brake booster. In FIG. 4, when the push rod 4 is moved to the right during brake operation, the oil piston 8 in the oil cylinder 11 is inserted through the insert 33A.
Is extruded. When the oil piston 8 is pushed to the right, the valve 17 is released from the pressure by the lifter 9, and the valve seal portion 26 is pressed against the valve seat 25.
When 16 is closed and liquid oil in the pressure chamber 15 in the oil cylinder 11 is pumped to a wheel cylinder (not shown), a braking action is performed.

When the braking action is released, the push rod 4 is moved to the left by the urging force of the spring 10 (see FIG. 1), and the oil piston 8 is also moved to the left accordingly. Then, since the valve 17 is pressed again by the lifter 9, the flow passage 16 is opened and the pressure oil pressure-fed to the wheel cylinder (not shown) returns to the oil cylinder 11.

As described above, in this type of brake booster, when the brake is actuated, the tip of the push rod 4 comes into direct contact with the slit 18 of the oil piston 8 (see FIG. 1), so that the oil piston 8 wears. The insert 33A is provided so as not to be damaged, and the bush rod 4, the insert 33A and the oil piston 8 are connected by the pin 20.

[Problems to be solved by the device]

However, the push rod 4 and the oil piston 8
When the insert 33A is interposed between the insert 33A and the insert 33A, a gap indicated by α is usually provided between the tip surface of the push rod 4 and the insert 33A in FIG. Occurs. Therefore, every time the brake is actuated, the tip spherical portion R of the push rod 4 collides with the insert 33A and a collision noise is generated. Especially for large vehicles such as buses,
There is a problem that the collision sound resonates with the floor near the brake booster and becomes loud.

An object of the present invention is to provide a brake booster capable of preventing a collision noise from being generated when a brake is actuated and preventing a driver and a passenger from feeling uncomfortable.

[Means for solving the problem]

In the brake booster according to the present invention, the power cylinder (3) and the oil cylinder (11) are continuously arranged so that the power piston (5) and the oil piston (8) are aligned on the same axis. The push rod (4) is fixed to the power piston (5) on the axis, and
This push rod (4) is the oil piston (8)
Is connected to the axial direction so as to be relatively movable within a predetermined range, and the inside of the oil cylinder (11) is adjacent to the push rod (4) by the oil piston (8). 14) and an output side pressure chamber (15) on the opposite side, and the oil piston (8) has a flow path (16) communicating with the liquid oil replenishment chamber (14) and the output side pressure chamber (15). ) Is formed, and a valve (17) for opening and closing the flow passage (16) as the oil piston (8) moves back and forth is provided in the flow passage (16). ) Is engaged with a lifter (9) that opens and closes the valve (17) according to the relative movement of the push rod (4) with the oil piston (8). A recess (31) facing the end surface of the push rod (4) is opened. In addition, an insert (33) is provided in the recess (31) between the bottom surface of the recess (31) and the push rod (4) so as to be movable in the axial direction. In the force device, a disc-shaped projecting portion (34) is concentrically projected on the surface of the insert (33) facing the bottom surface of the recess (31) while leaving a concave portion in the outer periphery in an annular shape, An elastic ring (22) is arranged on the outer periphery of the protrusion (34), and a circular plate (21) is interposed between the elastic ring (22) and the bottom surface of the recess (31). At the same time, the circular plate (21) is provided with a communication hole (32) for communicating the hollow portion of the elastic ring (22) with the replenishment chamber (14).
Further, the insert (33) and the tip end surface of the push rod (4) are in contact with each other.

[Operation] During braking, the power piston (5) in the power cylinder (3) moves to the oil piston side in the oil cylinder (11), and the push rod (4) also moves to the oil piston side accordingly. . By the movement of the push rod (4), the insert (33) abutting against the push rod (4) is also moved and the elastic ring (22) is compressed, and the flat end surface of the protruding portion (34) of the insert (33) is flat on the oil piston side. Abut each other. Then, the push rod (4) further moves to the oil piston side, the oil piston (8) is moved, the hydraulic pressure of the output side pressure chamber (15) becomes high, and the braking action is performed.

When the brake is released, the power piston (5) in the power cylinder (3) moves in the original direction, and accordingly, the push rod (4) also moves in the original direction. By the movement of the push rod (4), the insert (33) abutting against the push rod (4) is also moved and the elastic ring (22) is restored by elasticity, and the flat tip surface of the protrusion (34) of the insert (33) is a circular plate ( 21) leave. Further, since the valve (17) is opened by the lifter (9), the power piston (5) and the oil piston (8) return to their original state.

The volume of the hollow portion of the elastic ring (22) increases or decreases when the elastic ring (22) is compressed and restored and expanded and deformed when the brake is applied and when the brake is released as described above, but the hollow portion of the elastic ring (22) has a circular shape. Since oil freely flows in and out through the communication hole (32) formed in the plate (21), the elastic ring (22) is not expanded or contracted in its diameter. Therefore, the elastic ring (22) may come off the insert (33) or the protrusion (34)
It does not get caught between the circular plate (21) and the circular plate (21).

〔Example〕

FIG. 1 is a longitudinal sectional view showing a brake booster according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view of an essential part of FIG. 1, and FIG.
The drawing is a sectional view taken along the line III-III in FIG.

The brake booster includes a power cylinder portion 1 that converts air pressure into hydraulic pressure, and an oil cylinder portion 2 that transmits the hydraulic pressure to a wheel cylinder (not shown). The power cylinder unit 1 is a cylindrical power cylinder 3
And a power piston 5 fixed to one end of a push rod 4 arranged in the center of the power cylinder 3. The power piston 5 divides the inside of the power cylinder 1 into an air pressure chamber 6 and an atmosphere chamber 7. The tip end portion of the push rod 4 in the region forming the atmosphere chamber 7 side is linked with the oil piston 8 arranged in the oil cylinder portion 2 via a pin 20. A spring 10 is installed on the push rod 4, and the spring 10 urges the push rod 4 toward the pneumatic chamber 6.

A bearing portion 12 is formed at an end portion of the oil cylinder 11 constituting the oil cylinder portion 2 on the power cylinder 3 side, and the bearing portion 12 and a seal member 13 disposed on the axially outer side of the bearing portion 12 are used for pushing. The rod 4 is arranged so that it can move back and forth. An oil piston 8 is slidably arranged in the center of the oil cylinder 11, and the oil cylinder 8 divides the oil cylinder 11 into a liquid oil supply chamber 14 and an output side pressure chamber 15. .

A valve chamber 29 is opened in the oil piston 8 at an end portion on the output side pressure chamber 15 side, and a flow passage 16 communicating with the valve chamber 29 is formed from the valve chamber 29 toward the push rod 4 side. Up to the axial direction, and the valve rod 30 of the valve 17 is inserted into the flow path 16. Further, the oil piston 8 is formed with an axial slit 18 that opens to the end surface on the push rod side and extends to the flow path 16, and the slit 18 is fitted with the lifter 9 formed in a U-shaped plate shape. . When the lifter 9 is not in operation, the end surface on the power cylinder 3 side abuts the inner wall surface of the bearing portion 12, and the end surface on the oil cylinder 8 side pushes the valve rod 30 of the valve 17 and the valve seal portion 26 to the valve seat 25.
And the flow path 16 is opened.

Further, a circular recess 31 is formed on the slit 18 side of the oil piston 8 and opens at the end surface on the push rod 4 side, and the bottom of the recess 31 has a communication hole 32 in the center. The plate 21 is inserted and arranged. In addition, the recess 31
An insert 33 is inserted therein by inserting an elastic ring 22 as an elastic body. The insert 33 is formed into a cylindrical shape with a bottom, and a disc-shaped protruding portion 34 that is concentric and protrudes outward is formed on the bottom portion of the insert 33. The tip end surface of the protrusion 34 is formed as a flat surface parallel to the facing end surface of the plate 21, and the elastic ring 22 is formed on the outer periphery of the protrusion 34.
Is fitted. The circular plate 21 prevents the elastic ring 22 from being caught in the slit 18 of the oil piston 8 or damaged by the edge portion. Push rod 4 in this insert 33
The tip end portion of is inserted and the bottom surface of the insert 33 is always in contact with the tip end surface by the elastic force of the elastic ring 22. And the push rod 4, the insert 33 and the oil piston 8 are slit into them.
Pins 20 inserted in a direction orthogonal to 18 are integrally connected. In this state, the pin hole 35 provided in the push rod 4, the insert 33, and the oil piston 8 is formed in a size in which the pin 20 is loosely fitted, and the pin 20 loosely fitted in the pin hole 35 is the oil piston. A spring that is installed in a circumferential groove 36 provided on the outer periphery of
It is locked by 19

On the other hand, a stopper ring 23 is fixed to the opening edge portion of the valve chamber 29 of the oil piston 8.
A spring 24 between the valve 17 and the valve 17
It is installed so as to urge it to the side. The valve 17 closes the flow path 16 by bringing the valve seal portion 26 into close contact with the valve seat 25.

Incidentally, 27 is a flow path connected to a fluid reservoir 28, which is opened in the liquid oil supply chamber 14. Reference numerals 37 and 38 are a backup ring and a seal cup which are mounted in a ring groove formed on the outer circumference of the oil piston 8. Further, the output side pressure chamber 15 is connected to a wheel cylinder (not shown).

 Next, the operation will be described.

When a petal (not shown) is stepped on, compressed air from an air pressure chamber (not shown) is press-fitted into the air pressure chamber 6 of the power cylinder 3 according to the stepped amount. The compressed air that has been press-fitted into the air pressure chamber 6 causes the power piston 5 to spring 10.
It is pressure-fed to the right side in FIG.

Then, with the movement of the power piston 5, the push rod 4 is moved to the right side in FIG. By the movement of the push rod 4, the insert 33, which is always in contact with the tip end surface of the push rod 4 by the elastic force of the elastic ring 22, is moved rightward against the elastic ring 22.

Then, the elastic ring 22 is compressed, and the flat end surface of the protruding portion 34 of the insert 33 is brought into contact with the plate 21. At this time, since the insert 33 and the plate 21 are in flat contact with each other, generation of abnormal noise is prevented.

After the insert 33 contacts the plate 21, the oil piston 8 is moved to the right together with the push rod 4.
When the oil piston 8 is pushed out to the right, the contact between the back surface of the lifter 9 and the valve rod 30 of the valve 17 begins to separate from each other. Shortly after they started to separate, the valve 17 was pushed to the left by the biasing force of the spring 24, and the valve seal portion 26
Is pressed against the valve seat 25 to close the flow path 16.

In this state, when the oil piston 8 moves to the right and the hydraulic pressure in the output side pressure chamber 15 reaches a predetermined pressure, the liquid oil in the output side pressure chamber 15 is transferred to the wheel cylinder via a connector (not shown). It is pumped to (not shown) and a braking action is performed. In this case, since the volume in the liquid oil supply chamber 14 becomes large, the fluid reservoir 28,
Liquid oil is replenished into the liquid oil replenishing chamber 14 via the flow path 27.

When the depression of the pedal is released, the compressed air in the air pressure chamber 6 is discharged into the atmosphere through a predetermined exhaust port. Along with this, the push rod 4 is moved to the pneumatic chamber 6 side by the biasing force of the spring 10, and the power piston 8 moves to the first position.
It is moved to the left in the figure. At this time, the left end surface of the lifter 9 comes into contact with the inner wall surface of the bearing 12 and stands still, so that the rear surface of the lifter 9 pushes the valve 17 to the right.
As a result, the valve 17 is moved to the right against the urging force of the spring 24, the valve seal portion 26 is disengaged from the valve seat 25, the flow passage 16 is opened, and the power piston 5 and the oil piston 8 are in their original states. Return to.

Then, the liquid oil that has been pressure-fed to the wheel cylinder (not shown) is returned to the output side pressure chamber 15 and the braking action is released.

Needless to say, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.

For example, the insert 33 is not limited to the shape in which the protruding portion is formed outside the bottom portion of the bottomed cylindrical member shown in the above embodiment, but may be formed in the shape in which the protruding portion is formed on one end surface of the disk.

[Effect of device]

As described above, according to the present invention, there is no gap between the tip of the push rod and the insert, and
When the brake is operated when the brake is operated, the push rod and the insert are in contact with each other, and the flat tip surface of the insert abuts the oil piston side in a plane. No abnormal noise is generated due to collision.

[Brief description of drawings]

1 is a longitudinal sectional view showing an embodiment of the present invention, FIG. 2 is an enlarged sectional view of an essential part of FIG. 1, and FIG. 3 is a sectional view taken along line III-III of FIG. FIG. 4 is an enlarged cross-sectional view of essential parts showing a conventional brake booster. 1 ... Power cylinder part, 2 ... Oil cylinder part, 3
...... Power cylinder, 4 ... Push rod, 5 ... Power piston, 6 ... Pneumatic chamber, 7 ... Atmosphere chamber, 8 ...
Oil piston, 9 …… Lifter, 10 …… Spring, 11
…… Oil cylinder, 12 …… Bearing part, 13 …… Seal member, 14 …… Liquid oil supply chamber, 15 …… Output side pressure chamber, 16 …… Flow path, 17 …… Valve, 18 …… Slit, 19 ...... Spring, 20 …… pin, 21 …… plate, 22 …… elastic ring,
23 …… Stopper ring, 24 …… Spring, 25 …… Valve seat, 26 …… Valve seal part, 27 …… Flow passage, 28 …… Fluid reservoir, 29 …… Valve chamber, 30 …… Valve rod, 31… … Recess, 32
...... Communication hole, 33 …… Insert, 34 …… Projection, 35 ……
Pin hole, 36 ... Circumferential groove, 37 ... Backup ring, 38 ...
… Seal cup, α …… Gap.

Claims (1)

[Scope of utility model registration request] 1. A power cylinder (3) and an oil cylinder (11) are connected in series such that the power piston (5) and the oil piston (8) are aligned on the same axis, and the power piston (5). A push rod (4) is fixed on the axis, and the push rod (4) is connected to the oil piston (8) so as to be capable of relative movement within the predetermined range in the axial direction. The oil cylinder (11) is partitioned by the oil piston (8) into a liquid oil replenishing chamber (14) adjacent to the push rod (4) and an output pressure chamber (15) on the opposite side.
The oil piston (8) is formed with a flow path (16) communicating with the liquid oil supply chamber (14) and the output side pressure chamber (15), and the flow path (16) has the flow path (16). A valve (17) is provided for opening and closing the flow path (16) as the valve (8) moves forward and backward, and the valve (17) moves the push rod (4) relative to the oil piston (8). A lifter (9) for opening and closing the valve (17) is engaged with the oil piston (8), and a recess (31) facing the end face of the push rod (4) is formed in the oil piston (8). In addition, an insert (33) is provided in the recess (31) between the bottom surface of the recess (31) and the push rod (4) so as to be movable in the axial direction. Facing the bottom surface of the recess (31) of the insert (33) in the force device. Has a disk-shaped protrusion (34) concentrically protruding from the outer periphery, leaving a recess in the annular shape, and an elastic ring (22) is disposed on the outer periphery of the protrusion (34). A circular plate (21) is provided between the elastic ring (22) and the bottom surface of the recess (31), and the circular plate (21) is provided in the hollow portion of the elastic ring (22). A communication hole (32) communicating with the replenishment chamber (14) is provided, and the insert (33) and the push rod (4) are provided.
The brake booster is characterized in that it is in contact with the front end surface of the brake booster.