JPH061893Y2 - Pneumatic booster - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a pneumatic booster provided in a brake system of a vehicle or the like.

(Prior Art) A brake system of a vehicle or the like is provided with a pneumatic booster for assisting the pedaling force of a brake pedal to act on a master cylinder.

In this pneumatic booster, the inside of the booster is divided into two chambers by a power piston attached to the front part of the valve body and a diaphragm, and one chamber is a constant pressure chamber communicating with a negative pressure source. The other chamber is used as a variable pressure chamber that selectively communicates with a negative pressure source or the atmosphere, and a valve device that switches communication between the variable pressure chamber and the negative pressure source or the atmosphere is arranged in the tubular portion of the valve body to operate the valve device. Insert the input shaft to be inserted into the tubular portion,
There is an output shaft provided with an output shaft for outputting to the master cylinder a force that assists the input from the input shaft when the power piston moves due to the pressure difference from the constant pressure chamber when the atmosphere is introduced into the variable pressure chamber.

In this type of pneumatic booster, when the atmosphere is introduced into the variable pressure chamber by switching the valve device, since the passage area of the valve device and the passage connecting the inside of the tubular portion and the variable pressure chamber are small, the atmosphere is It is circulated at high speed and produces suction noise.

Therefore, various muffling devices have been proposed in order to prevent the passengers from feeling uncomfortable due to the suction sound being transmitted to the inside of the vehicle.

As the structure of the conventional silencer,
Between the valve device in the tubular portion of the valve body and the opening on the atmosphere side, a filter having a mesh size that is capable of removing dust in the atmosphere and a mesh having a mesh size finer than that of the filter, and a suction noise There is one in which a silencer is installed in parallel so as to reduce sound energy and prevent it from being transmitted to the outside.

In addition, as for the one that has further enhanced the sound deadening effect,
There are those proposed in Japanese Patent No. 23654, Japanese Patent Laid-Open No. 58-110359, and the like.

In Japanese Utility Model Publication No. 59-23654, a baffle plate is provided in a filter provided in an air passage between a valve device and an air suction hole of a dust boot covering the valve body, and the air passage is provided at least once or more. A silencer made by bending is proposed.

Further, in Japanese Patent Laid-Open No. 58-110359, a structure is formed in which a through hole for communicating the valve device side and the outside is formed in the tubular portion of the valve body, and the input shaft is surrounded and joined to the inner circumference of the tubular portion. A silencer has been proposed.

(Problems to be Solved by the Invention) However, the above conventional silencer has the following problems.

With the filter and silencer arranged in the tubular part of the valve body, the noise reduction effect can be further enhanced by increasing the thickness of the silencer or making the mesh coarser, but it becomes the intake resistance. This causes a delay in the operation of the pneumatic booster, and there is a problem in that a sufficient silencing effect cannot be expected.

In the case where the air passage is bent by the baffle plate provided in the filter, the shape of the dust boot is complicated, the mold for manufacturing the dust boot becomes expensive, and the assembly of the filter etc. is not easy. There is a problem that the cost may increase.

Further, in the case where the muffling device having the through hole is provided, the muffling effect is sufficient for the sound of the predetermined wavelength, but there is a fear that other things may go out directly through the through hole. ,
There is a problem that there is a possibility that sufficient muffling cannot be achieved.

The present invention has been made in view of the above problems, and an object thereof is to provide a pneumatic booster having a silencer having a simple structure and a high silencing effect.

(Means for Solving the Problems) The pneumatic booster of the present invention has a simple structure and can be expected to sufficiently reduce the suction noise. A filter for removing dust is arranged, and on the opposite side of the filter from the valve device, a silencer having a passage formed of a gap between the filter and the inner circumference of the tubular portion, and the outer circumference of the input shaft are provided. It is characterized in that a silencer having a passage formed by a gap between them is sequentially arranged.

(Operation) According to the above configuration, since the silencer having the passage provided on the outer peripheral side and the silencer having the passage provided on the inner peripheral side are combined, even if the silencer is thickened to enhance the silencing effect,
The flow rate of the atmosphere can be secured by the passage of each silencer.
Further, since the passages are located at different positions in the radial direction, the suction sound does not directly come out to the outside. Further, since the filter and the silencer are combined, the manufacturing cost does not increase as compared with the conventional commonly used silencer.

(Example) Next, the Example of this invention is described based on drawing.

First, a first embodiment will be described with reference to FIGS. 1 and 2.

This embodiment is a tandem type pneumatic booster, in which a front shell 1 and a rear shell 2 are joined by caulking on the outer peripheral side via a center plate 3 to form a booster main body (hereinafter referred to as a main body) 4. The main body 4 is divided into two spaces by the center plate 3. The main body 4 is provided with a valve body 5 which is movable through the rear shell 2 and the center plate 3 in the axial direction thereof, and the front portion (left side in the figure) of the valve body 5 is made to correspond to each of the above spaces. The power pistons 6, 7 and the inner peripheral sides of the diaphragms 8, 9 are fixed.
The outer peripheral side of 9 is fixed to the main body 4 side. With this configuration, the space on the front side in the main body 4 is partitioned into the front constant pressure chamber 10 and the front variable pressure chamber 11, and the space on the rear side is the rear constant pressure chamber 12.
And rear transformer room 13. Front constant pressure chamber 10
The negative pressure introducing pipe 14 is connected to a negative pressure source such as an intake manifold (not shown).

A tubular portion 5a is formed on the valve body 5, and a large diameter inner diameter portion 5b and a small diameter inner diameter portion 5c are formed from the rear side in the tubular portion 5a, and the small diameter inner diameter portion 5c is A plunger 16 connected to an input shaft 15 that penetrates the large-diameter inner diameter portion 5b from the rear is slidably fitted. The plunger 16 has a key member 17
Due to this, the relative movement with the valve body 5 is restricted within a certain range.

A seat portion 5d is formed at a step portion between the small diameter inner diameter portion 5b and the small diameter inner diameter portion 5c of the valve body 5, and a seat portion 16a is also formed at the rear end of the plunger 16.
The large-diameter inner diameter portion 5b is provided with a poppet valve 18 which can be seated on and separated from the seat portions 5d and 16a. A valve device is constituted by the seat portions 5d, 16a and the poppet valve 18. In addition, 19 is the poppet valve 18 seat portion 5d, 1
Reference numeral 20 denotes a spring that urges the input shaft 15 toward the rear side, and 20 denotes a spring that urges the input shaft 15 rearward.

In the valve body 5, a passage 21 is formed, one of which opens into the front constant pressure chamber 10 and the other of which opens between the poppet valve 18 inside the valve body 5 and the seat portion 5d.
A passage 22 communicating with the rear constant pressure chamber 12 is connected in the middle of 21. The valve body 5 has a tubular portion 5a on one side.
A passage 23 that opens to the front side of the seat portion 5d inside and the other of which opens to the rear transformer chamber 13 and a passage 24 that opens to the rear transformer chamber 13 and one of which opens to the front transformer chamber 11 are formed. There is.

A slidable output shaft 25 is attached to the valve body 5 by fitting a convex portion 5e formed on the front portion of the valve body 5 into a concave portion 25a at the rear end. Part 5e
And the recess 25a of the output shaft 25 between the reaction disc 2
6 is interposed. The tip of the output shaft 25 is in contact with the input side piston of a master cylinder (not shown). In addition,
27 is a return spring, which biases the valve body 5 rearward.

Inside the large diameter inner diameter part 5b of the valve body 5, a poppet valve
A filter 28, a first silencer 29, a second silencer 30, and a filter 31 are sequentially arranged from the 18 side. The filters 28 and 31 are made of sponge or the like, and are formed to have a coarseness such that dust in the atmosphere can be removed. Further, as shown in FIG. 2, the first silencer 29 is formed with a plurality of U-shaped grooves 29a extending in the axial direction on the outer peripheral side, and the inner periphery of the large-diameter inner diameter portion 5b and this groove 29a. The gap formed by the above constitutes the passage 32. The second silencer has a large inner diameter, and a gap formed between the second silencer and the input shaft 15 constitutes the passage 33. The silencers 29, 30 are made of felt that is compression-molded with a finer mesh than the filters 28, 31.

The operation of the pneumatic booster having the above configuration will be described.

In the initial state of FIG. 1 of the pneumatic booster, each constant pressure chamber 1
0, 12 and the variable pressure chambers 11, 13 are in a negative pressure state, and the power pistons 6, 7 are located on the rear side by the return spring 27.

When you push the brake pedal to move the input shaft 15 forward,
From the state shown in FIG. 1, the plunger 16 moves forward, the seat portion 16a of the plunger 16 is separated from the poppet valve 18, and the atmosphere passes from the tubular portion 5a of the valve body 5 through the passage 23 to the rear transformation chamber 13 In addition, the atmosphere is also introduced into the front transformer room 11 through the passage 24. This allows
A pressure difference is generated between the constant pressure chambers 10 and 12 and the variable pressure chambers 11 and 13, so that the power pistons 6 and 7 move forward, and the valve body 5 moves forward accordingly. Due to this movement, the input from the input shaft 15 is assisted, and the boosted force from the output shaft 25 acts on the master cylinder.

During this operation, the suction noise generated when the atmosphere flows through the gap between the poppet valve 18 and the seat portion 16a and the passage 23 is
The sound energy of the suction sound is reduced by the silencer 29 and the second silencer 30 so that the sound is silenced. As described above, by providing the two silencers, the thickness of the silencer is substantially increased to enhance the sound deadening effect so that the suction sound is not transmitted to the vehicle interior side, and the inside of the tubular portion 5a of the valve body 5 is prevented. The flow rate of the atmosphere flowing through the passages 32 and 33 formed by the silencers 29 and 30 is also secured, so that there is no delay in the operation of the booster. Also, the passage
Since 32 and 33 are located at different positions in the radial direction, the direct suction noise does not come out to the vehicle compartment side.

It should be noted that disposing the filter 28 on the poppet valve 18 side of the first silencer 29 also has a function of preventing fine bristles constituting the silencers 29, 30 from entering the respective variable pressure chambers 11, 13.

In this way, it is possible to more reliably reduce the transmission of the suction sound to the interior side of the vehicle with the same simple structure as the conventional general silencer.

Next, a second embodiment will be described with reference to FIG. The same members as those of the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

In the large-diameter inner diameter portion 5b of the tubular portion 5a of the valve body 5, a filter 28 from the poppet valve 18 side, a first silencer 29 having a groove 29a formed outside, a spacer 34, a second silencer.
30 and filter 31 are arranged in order.

The spacer 34 includes a first silencer 29 and a second silencer.
It is for forming a gap 35 between 30 and 30.
As shown in (a) and (b), four axially projecting bent portions 34a are formed on the inner circumference of the annular shape, and the ends thereof are fitted to the inner circumference of the second silencer 30. It is the fitting portion 34b. Then, the passage 32 of the first silencer 29 and the passage 33 of the second silencer 30 communicate with each other through the gap 35 formed by the spacer 34 to form a bent passage in the tubular portion 5a.

According to the above configuration, the first and second silencers 29,3
With 0, it is possible to reduce the transmission of the suction sound to the inside of the vehicle, and, compared with the first embodiment, the first silencer 29
Even if the thickness of the second silencer 30 is increased, the curved passage can ensure a sufficient flow rate of the atmosphere.

A third embodiment will be described with reference to FIG. Also in this embodiment, the same members as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

A filter 28, a first silencer 29, and a second silencer 30 are sequentially arranged in the large-diameter inner diameter portion 5b of the tubular portion 5a of the valve body 5 from the poppet valve 18 side. The input shaft 15 is formed with a flange portion 15a.
The first silencer 29 is positioned on the rear side in the axial direction, and a step portion 5f is formed on the inner periphery of the large-diameter inner diameter portion 5b of the valve body 5, and the step portion 5f is formed.
Positioning of the second silencer 30 on the front side in the axial direction is performed by the. Then, similarly to the second embodiment, a gap 35 is formed between the first silencer 29 and the second silencer 30, and the gap 35 and the passages 32, 33 of each silencer 29, 30.
A curved passage is formed by the.

According to this configuration, the same operation as that of the second embodiment is achieved, but the number of parts can be reduced as compared with the second embodiment because the spacer 34 is not required.

Next, a fourth embodiment will be described with reference to FIG. Also in this embodiment, the same members as those in the first embodiment are designated by the same reference numerals and detailed description thereof will be omitted.

A filter 28, a first silencer 29, a filter 31, and a second silencer 30 are arranged in this order from the poppet valve 18 side in the large-diameter inner diameter portion 5b of the tubular portion 5a of the valve body 5.

According to this configuration, the first and second silencers 29, 30
As a result, the transmission of the suction sound to the inside of the vehicle is reduced, and the flow rate of the atmosphere is secured by the passage 32 of the first silencer 29 and the passage 33 of the second silencer 30. At this time,
Since the filter 31 is interposed between the silencers 29, 30, the dust in the atmosphere flowing through the passages 32, 33 of the silencers 29, 30 is surely removed.

In this embodiment, the first and second silencers 2
The shapes of the passages 32, 33 formed in 9, 30 are not limited to those in the above embodiment, and may be any shape as long as they have a flow passage area capable of ensuring the flow rate of the atmosphere.

Further, the positions of the first silencer 29 and the second silencer 30 are not limited to those in the above embodiment, and the second silencer 30 may be arranged closer to the filter 28 than the first silencer 29.

(Effect of the Invention) As described in detail above, according to the present invention, by providing the silencer having the passage on the outer peripheral side and the silencer having the passage on the inner peripheral side, the suction noise of the atmospheric air generated during the operation is generated on the inside of the vehicle It is possible to reliably reduce the transmission to the air and to secure the flow rate of the atmosphere by the passage of each silencer so that the operation delay does not occur. In addition, the structure is almost the same as the conventional commonly used silencer, so the cost does not increase significantly, and the present invention is a simple modification to the conventional pneumatic booster. Can be applied.

[Brief description of drawings]

1 is an overall longitudinal sectional view showing a first embodiment of a pneumatic booster of the present invention, and FIG. 2 is a front view of a first silencer provided in the pneumatic booster shown in FIG. 3 and 4 are longitudinal sectional views of a main part of a second embodiment of the pneumatic booster according to the present invention, and FIGS. 4 (a) and 4 (b) are pneumatic boosters shown in FIG. Fig. 4 (a) shows the spacer 34 provided on the spacer 3.
4 is a front view, FIG. 4 (b) is a sectional view taken along the line BB of FIG. 4 (a), and FIG. 5 is a longitudinal sectional view of a main part of a third embodiment of the pneumatic booster of the present invention. FIG. 6 and FIG. 6 are longitudinal cross-sectional views of the essential parts of a fourth embodiment of the pneumatic booster of the present invention. 4 ... Booster main body, 5 ... Valve body 5a ... Cylindrical part 6, 7 ... Power piston 10 ... Front constant pressure chamber, 11 ... Rear constant pressure chamber 12 ... Front variable pressure chamber, 13 ... Rear variable pressure chamber 15 ... Input shaft, 5d , 16a ... Seat part 18 ... Poppet valve, 25 ... Output shaft 28 ... Filter, 29 ... First silencer 30 ... Second silencer 32, 33 ... Passage

Claims (1)

[Scope of utility model registration request] 1. A booster main body divided into a constant pressure chamber communicating with a negative pressure source and a variable pressure chamber selectively communicating with the negative pressure source or the atmosphere by a power piston and a diaphragm attached to a front portion of a valve body. A valve device arranged in the tubular portion of the valve body for switching communication between the variable pressure chamber and a negative pressure source or the atmosphere; an input shaft inserted into the tubular portion for operating the valve device; In a pneumatic booster consisting of an output shaft that outputs to the master cylinder a force that assists the input from the input shaft by a power piston that moves due to the pressure difference between the pressure chamber and the variable pressure chamber, A filter for removing dust in the atmosphere is disposed, and a silencer having a passage formed by a gap between the filter and the inner periphery of the tubular portion is provided on the side opposite to the valve device of the filter, and the input shaft. Outside Pneumatic booster, characterized in that successively arranged and silencer having a passage comprising a gap between.