JPH0427734Y2 - - Google Patents

Description

[Detailed explanation of the invention] A. Purpose of the invention (1) Industrial application field This invention fixes a negative pressure introduction pipe to a booster shell to which a hose connected to a negative pressure source is connected, and connects the negative pressure introduction pipe through this negative pressure introduction pipe. The present invention relates to a negative pressure introduction device in a negative pressure booster, which introduces negative pressure from a negative pressure source into a negative pressure chamber within a booster shell.

(2) Prior art This negative pressure introducing device is known, for example, from the Japanese Patent Publication No. 1983-
This is already known as disclosed in Japanese Patent No. 17305.

(3) Problems to be solved by the invention Recently, there have been requests for reducing the operating noise of negative pressure boosters, and the inventors of the present invention have identified the cause of the operating noise as follows.

In other words, in a negative pressure booster, each time the operation is released, negative pressure is supplied from the negative pressure source to the operating chamber, and at that time, air flows at high speed toward the negative pressure source in the hose connected to the negative pressure source. This causes intake noise, which is reflected in the booster shell and produces a harsh operating sound.

Therefore, an object of the present invention is to provide a negative pressure introducing device for a negative pressure booster that can effectively reduce the above-mentioned operating noise.

B. Structure of the device (1) Means for solving the problems In order to achieve the above object, the present invention provides a noise reduction device installed in the negative pressure chamber at the opening of the negative pressure introduction pipe to the negative pressure chamber. It is characterized by being equipped with a device.

(2) Effect When replenishing negative pressure from the negative pressure source to the negative pressure chamber in the booster shell, the air in the negative pressure chamber passes through the muffler, and then is sucked into the negative pressure source through the negative pressure introduction pipe and hose. Ru. At this time, the intake noise generated within the hose is attenuated by the muffler and then released into the negative pressure chamber, so it does not cause any echo in the booster shell.

Since the muffler is installed in the negative pressure chamber, it is possible to use a muffler with a large volume by utilizing the dead space of the negative pressure chamber, which increases the damping effect of the muffler and reduces ventilation resistance. can be achieved.

(3) Examples Examples of the present invention will be described below with reference to the drawings.

First, in FIG. 1 showing a first embodiment of the present invention, a brake master cylinder M operated by the booster B is attached to the front surface of a booster shell 1 of a negative pressure booster B.

The booster shell 1 includes a pair of front and rear shell halves 1a, 1b whose opposite ends are connected to each other, and is sandwiched between the two shell halves 1a, 1b so that the inside of the booster shell 1 is divided into a front shell chamber 2 and a rear shell chamber. 3, and a partition wall plate 1c that partitions the rear shell half body 1b into
is supported by a vehicle body (not shown).

The front shell chamber 2 includes a front booster piston 4 accommodated therein so as to be able to reciprocate back and forth, and a front booster piston 4 which is superposed and bonded to the rear surface and sandwiched between the front shell half 1a and the partition wall plate 1c. The diaphragm 5 creates a front negative pressure chamber 2a on the front side and a front working chamber 2 on the rear side.
It is divided into b. The rear shell chamber 3 also includes a rear booster piston 6 accommodated therein so as to be able to reciprocate back and forth, and a rear diaphragm 7 which is superimposed on the rear surface and fixed between the shell halves 1a and 1b together with the partition wall plate 1c. Accordingly, it is divided into a rear negative pressure chamber 3a on the front side and a rear working chamber 3b on the rear side.

An opening 58 is provided in the front wall of the front shell 1a, and the base end of the negative pressure introduction pipe 29 is fixed to the front surface of the front shell 1a by welding or the like, surrounding the opening 58. A hose 60 connected to a negative pressure source 59 (for example, inside the intake manifold of the engine) is connected to the tip of the negative pressure introduction pipe 29. This hose 60 is provided with a check valve 61 therein to prevent backflow of negative pressure from the front negative pressure chamber 2a to the negative pressure source 59.

A muffler 62 disposed in the front negative pressure chamber 2a is attached to the opening 58 as follows.

That is, the silencer 62 includes a box body 65 having a through hole 63 in the front wall and a large number of small holes 64, 64, . . . in the other side walls,
The box body 65 is composed of a plurality of elastic locking claws 66, 66, .
By elastically locking the periphery, the silencer 62
is installed. Therefore, the front negative pressure chamber 1a is always in communication with the negative pressure source 59 via the muffler 62, the negative pressure introduction pipe 29, and the hose 60.

The front and rear booster pistons 4 and 6 are each formed into an annular shape from a steel plate, and these are attached to the partition wall plate 1c.
It is connected to both ends of a piston boss 10 made of synthetic resin which is slidably supported via a bush 8 and a seal member 9 in the following manner.

That is, the depth of the piston boss 10 is
A circular recess 11 reaching approximately half the length of 0 is formed on the front end surface, and a flange 12 is protruded from the rear end of the outer peripheral surface at a location slightly forward.
The circular recess 11 includes a front booster piston 4.
A connecting tube 1 with an end wall plate 13a connected to the inner peripheral end of the
3 are fitted together, and a presser plate 14 that cooperates with the flange 12 to clamp the rear booster piston 6 is superimposed on the rear end surface of the piston boss 10. The presser plate 14, the piston boss 10, and the end wall plate 13a are connected to a plurality of (three in the illustration) through bolts 15 surrounding the axis of the piston boss 10,
They are fixed to each other by a nut 16 screwed into them.

At this time, an annular retainer 17 is inserted between the front booster piston 4 and the front end surface of the piston boss 10 to cover the inner peripheral bead 5a of the front diaphragm 5 and the outer peripheral surface and rear surface of the inner peripheral bead 5a. is,
Furthermore, an inner peripheral bead 7a of a rear diaphragm 7 that surrounds the inner peripheral end of the rear booster piston 6 is inserted between the flange 12 and the presser plate 14. Therefore, at the same time that the front and rear booster pistons 4, 6 and the piston boss 10 are connected to each other,
Inner peripheral beads 5a, 7a of each diaphragm 5, 7 are fixed to corresponding booster pistons 4, 6.

Further, a sealing member 19 is attached to the bolt hole 18 provided in the piston boss 10 for insertion of the through bolt 15, so that the bolt hole 18
communication between the front negative pressure chamber 2a and the rear working chamber 3b is blocked. Further, a sealing member 20 surrounding the plurality of through bolts 15 is interposed between the end wall plate 13a and the piston boss 10, thereby sealing the contact surface between the end wall plate 13a and the piston boss 10. The first and second bifurcated ports 30 described later by
31 is blocked.

Each through bolt 15 is arranged with its square head 15a facing the rear working chamber 3b side, and its square head 15
A recess 21 (see FIG. 2) of the same shape is formed in the presser plate 14, into which the recess 21 (see FIG. 2) is fitted non-rotatably. Therefore, when the nut 16 is passed through and screwed onto the bolt 15 on the front negative pressure chamber 2a side, the bolt 15 is prevented from rotating, so the nut 16 can be tightened reliably.

The seat plate 22 is overlappingly bonded to the end wall plate 13a of the connecting cylinder 13 using the through bolts 15 and nuts 16. This seat plate 22 has a plurality of nuts 16
It is provided with a plurality of seats 22a (see FIG. 3) that are raised higher than the height of the nut 16 between them, and a return spring 23 is compressed between the seats 22a and the front shell half 1a. . The spring force of the return spring 23 always urges the piston boss 10 and therefore both booster pistons 4 and 6 in the backward direction. The backward limit of both booster pistons 4 and 6 is regulated by a large number of protrusions 24 raised on the rear surface of rear diaphragm 6 abutting against the rear wall of booster shell 1 .

The front negative pressure source chamber 2a, which communicates with the negative pressure source 59, is also constantly communicated with the rear negative pressure chamber 3a via the first bifurcated port 30 formed in the piston boss 10. In addition, both the front and rear working chambers 2b and 3b are provided with a piston boss 10.
The control valve 32 communicates with the front and rear negative pressure chambers 2a, 3a and the end wall 26 of the rear extension cylinder 26 through a second bifurcated port 31 formed in the
Communication is alternately switched between the air inlet port 33 and the air inlet port 33 which opens at the air intake port 33a.

Inside the valve cylinder 25, an input rod 35 connected to the brake pedal 34 and the control valve 32 controlled by the input rod 35 are provided as follows. That is, a valve piston 38 is slid into the front part of the valve cylinder 25, and the front end of an input rod 35 passing through the air inlet 33 is swingably connected to the valve piston 38. Further, an annular first valve seat 40 ₁ is protruded from the inner peripheral surface of the valve cylinder 25 , and an annular second valve seat 40 surrounded by the annular first valve seat 40 1 is provided.
₂ is formed on the rear end surface of the valve piston 38, and a valve body 41 that cooperates with these valve seats 40 ₁ and 40 ₂ is attached to the valve cylinder 25.
located within. The valve body 41 is made of rubber and has a cylindrical shape with both front and rear ends open, and the rear end, that is, the base end 41a, is held by a holding cylinder 42 fitted to the inner peripheral surface of the valve cylinder 25. It is maintained in close contact with the inner peripheral surface of the cylinder 25. The valve body 41 includes a thin flexible portion 41b bent radially inward from the base end 41a, and a thick valve portion 41c continuous to the front end of the flexible portion 41b. 41c is arranged opposite to the first and second valve seats 40 ₁ and 40 ₂ .

The valve part 41c can be moved back and forth by deforming the flexible part 41b, and is seated on the first and second valve seats 40 ₁ and 40 ₂ when moving forward, and is received at the front end of the holding cylinder 42 when retreating. It can be stopped.

An annular reinforcing plate 43 is embedded in the valve portion 41c,
A valve spring 44 is compressed between this and the input rod 35 and urges the valve portion 41c toward both valve seats 40 ₁ and 40 ₂ .

On the inner surface of the valve cylinder 25, one end of the first bifurcated port 30 is located outside the first valve seat ₄₀₁ , and one end of the first bifurcated port 30 is located outside the first valve seat 401.
0 ₁ , one end of the second bifurcated port 31 opens, respectively.

Further, the inside of the second valve seat 40 ₂ communicates with the atmosphere inlet 33 through the hollow portion of the valve body 41 and the holding cylinder 42 .

Thus, the valve body 41, the valve spring 44, and the first valve seat 40
_{The first} and second valve seats 40 ₂ constitute the control valve 32 .

Between the input rod 35 and the holding cylinder 42, the input rod 35
A return spring 45 is provided that urges the return spring 45 toward its retraction limit.

The retraction limit of the input rod 35 is determined by a stopper plate 46 that is screwed to the input rod 35 so as to be able to move forward and backward.
It is regulated by contacting the inner surface of the end wall 26a. Therefore, by rotating the stopper plate 46, the screwing position between the stopper plate 46 and the input rod 35 changes, so that the retraction limit of the input rod 35 can be adjusted back and forth. The fixing of the stopper plate 46 after this adjustment is as follows:
This is done by tightening a lock nut 47 which is similarly screwed onto the input rod 35. The stopper plate 46 includes
A ventilation hole 48 is provided to prevent this from blocking the air inlet 33.

The valve cylinder 25 is provided with an air filter 4 for filtering air taken into the valve cylinder 25 from the atmosphere inlet 33.
9 is attached to surround the input rod 35. This air filter 49 has appropriate flexibility so as not to impede relative displacement between the input rod 35 and the valve cylinder 25.

The piston boss 10 has a large cylinder hole 37 that opens at the center of its front surface, and a large cylinder hole 37 that opens at the center of the front surface.
and a small cylinder hole 3 whose both ends are open inside the valve cylinder 25.
6 is provided. And in the small cylinder 36,
Integral with the valve piston 38 or valve piston 38
A reaction piston 52 that comes into contact with the large cylinder hole 37 is slidably fitted with an elastic piston 50 that faces the reaction piston 52 and an output piston 51 that is superimposed on the front surface of the elastic piston 50.
In order to prevent the output piston 51 from being pulled out of the large cylinder hole 37, the inner peripheral edge of the end wall plate 13a is extended to the opening of the large cylinder hole 37.

An output rod 53 is provided protruding from the front surface of the output piston 51, and this output rod 53 is connected to the piston 55 of the brake master cylinder M.

Next, the operation of this embodiment will be explained. First, when the negative pressure booster B is at rest, as shown in Fig. 1,
The input rod 35 is located at the backward limit, and the control valve 32 has the valve portion 41c seated on the first and second valve seats 40 ₁ and 40 ₂ so that both the front and rear working chambers 2b and 3b are connected to both the negative pressure chambers 2.
The control valve 32 is in a neutral state where it is disconnected from both the negative pressure chambers 2a and 3a and the atmospheric air inlet 33. Negative pressure is stored, and the negative pressure appropriately diluted with the atmosphere is maintained in both working chambers 2b and 3b. In this way, a slight forward force is applied to the front and rear booster pistons 4 and 6 due to the pressure difference generated between the negative pressure chamber 2a and the working chamber 2b at the front, and between the negative pressure chamber 3a and the working chamber 3b at the rear. ,
These forward forces are balanced with the elastic force of the return spring 23, so that both booster pistons 4 and 6 are stopped when they have advanced slightly from the retraction limit.

Now, when the brake pedal 34 is depressed to brake the vehicle and the input rod 3 and the valve piston 38 are moved forward, since both the booster pistons 4 and 6 are initially immobile, the second valve seat ₄₀₂ is moved to the valve portion 41c. The working chambers 2b and 3b are immediately separated from each other to communicate with the atmosphere inlet 33. As a result, the atmosphere is quickly introduced from the atmosphere inlet 33 into the working chambers 2b, 3b through the second valve seat ₄₀₂ and the second bifurcated port 31, in other words, the negative pressure that had been present in the working chambers 2b, 3b is is discharged into the atmosphere, and the chambers 2b and 3b are converted into both negative pressure chambers 2.
Since the pressure is higher than that of a and 3a, a large forward force is obtained based on the pressure difference between them, and both booster pistons 4 and 6 move forward in a responsive manner against the force of the return spring 23. The piston 55 of cylinder M is driven forward. thus,
Brake master cylinder M to brake pedal 34
It can be activated without delay when the driver depresses the brake pedal, and the brakes can be applied to the vehicle.

During such braking, the valve piston 38 also advances together with the input rod 35 and comes into contact with the elastic piston 50 via the reaction piston 52.
0 bulges and deforms toward the small cylinder hole 36 side in response to the actuation reaction force of both booster pistons 4 and 6, and a part of the reaction force acts on the reaction force piston 52, so that force is applied to the valve piston 38 and Feedback is provided to the brake pedal 34 via the input rod 35. Due to such a reaction force, the driver can sense the output of the output rod 53, that is, the magnitude of the braking force.

When the output of the output rod 53 exceeds the boosting limit point due to an increase in the pedal force on the brake pedal 34, that is, the input to the input rod 35, the front surface of the valve piston 38 comes into contact with the piston boss 10, so that the entire input is applied to the valve piston. 38, the output rod 53 via the piston boss 10, the elastic piston 50 and the output piston 51
As a result, the sum of the forward force due to the pressure difference between the booster pistons 4 and 6 and the forward force due to the input is output from the output rod 53.

Next, when the pedal force on the brake pedal 34 is released, the input rod 35 moves back together with the valve piston 38 due to the elastic force of the return spring 45, and the second valve seat 4
0 ₂ is seated on the valve portion 41c of the valve body 41, and the valve portion 41c is largely separated from the first valve portion 40 ₁ , so that both working chambers 2b and 3b are replaced by both negative pressure chambers 2a and 3.
a, the pressure difference between the front and rear of each booster piston 4, 6 disappears immediately, and therefore both booster pistons 4, 6 retreat with the elastic force of the return spring 23, releasing the operation of the brake master cylinder M. I will do it. Then, when the input rod 35 returns to the retraction limit where the stopper plate 46 comes into contact with the partition wall 26a of the extension tube 26, the rear booster piston 6 temporarily pushes the protrusion 24 of the rear diaphragm 7 into the booster shell, as shown in FIG. 1 returns to the retraction limit where it comes into contact with the rear wall of 1, and this time, the first valve seat ₄₀₁ is seated on the valve seat 41c, and the valve part 41c is slightly separated from the second valve seat ₄₀₂ , so that both working chambers are closed again. 2b, 3b, the resulting pressure difference causes both booster pistons 4, 6 to move forward a little, and the space between the second valve seat ₄₀₂ and the valve part 41c disappears, and the control valve 32 is initially to a neutral state. In this way, the negative pressure diluted with the atmosphere is maintained in both working chambers 2b and 3b, and the negative pressure booster B enters the rest state as shown in FIG.

By the way, when the input rod 35 retreats, the negative pressure chamber 2
Negative pressure flows from the former to the latter until the pressures in the working chambers a, 3a and the working chambers 2b, 3b are the same, and as a result, the negative pressure chamber 2
When the negative pressures a and 3a decrease, the check valve 61 opens and negative pressure is supplied from the negative pressure source 59 to the front negative pressure chamber 2a through the hose 60, the negative pressure introduction pipe 29, and the muffler 62. At that time, when the intake noise generated in the hose 60 passes through the negative pressure introduction pipe 29, it is attenuated by the inside of the box 65 of the silencer 62 and the numerous small holes 64, 64, etc., so that it reverberates in the booster shell 1. It doesn't reach.

FIG. 5 shows a second embodiment of the present invention, in which through holes 63 and 6 are provided in both the front and rear walls of a box body 65 of a silencer 62.
3' is provided, and the structure is the same as that of the previous embodiment, except that the box body 65 is filled with a sound absorbing material 67 such as a breathable foam. In this embodiment, the intake noise generated by the hose 60 can be attenuated by the sound absorbing material 67 inside the box body 65.

C. Effects of the invention As described above, according to the invention, since a silencer installed in the negative pressure chamber is attached to the opening of the negative pressure introduction pipe to the negative pressure chamber, the negative pressure source and the negative pressure introduction The intake noise generated in the hose connecting the pipes is attenuated by the muffler in the negative pressure chamber, which can greatly contribute to reducing the operating noise of the negative pressure booster. In particular, the muffler in the negative pressure chamber can have a large volume by utilizing the dead space in the chamber, so it is important to ensure that the muffler has good ventilation, which will hinder the supply of negative pressure to the negative pressure chamber. It is possible to prevent the noise from occurring and to sufficiently enhance the silencing effect.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal cross-sectional side view of a negative pressure booster according to the first embodiment in a rest state, and FIGS. 2 and 3 are lines taken along lines - and - in FIG. 4 is a partial longitudinal sectional side view showing the state immediately before the negative pressure booster returns to a resting state after completing its operation, and FIG. 5 is a longitudinal sectional view of the main parts of the negative pressure booster according to the second embodiment. be. B... Negative pressure booster, 1... Booster shell,
2a...Front negative pressure chamber, 3a...Rear negative pressure chamber, 29
... Negative pressure introduction pipe, 59 ... Negative pressure source, 60 ... Hose, 62 ... Silencer.

Claims (1)

[Scope of utility model registration request] A negative pressure introduction pipe to which a hose connected to a negative pressure source is connected is fixed to the booster shell, and the negative pressure of the negative pressure source is introduced into the negative pressure chamber in the booster shell through this negative pressure introduction pipe. A negative pressure introduction device for a negative pressure booster, characterized in that a silencer disposed in the negative pressure chamber is attached to an opening of a negative pressure introduction pipe to the negative pressure chamber.