JPH07267075A - Noise eliminator for booster - Google Patents

Abstract

PURPOSE:To reduce an intake air sound without sacrificing responsiveness of a booster by forming a recesss and projection surface on an inside surface of a voltage transforming passage. CONSTITUTION:A voltage transforming passage 21 to be formed in a valve body 6 of a booster is formed of a circular cross-sectional inside surface 6b of the valve body 6 extending to the axial directional front side from a first valve seat 14 and a square cross-sectional inside surface 6c extending outward in the radial direction from there. A synthetic resin covering material 35 is integrally fitted to the inside surface 6b. Similarly, a covering material 36 is integrally fitted to the inside surface 6c. These covering materials 35 and 36 are formed in a circular or square cross-sectional cylinder shape according to shapes of the inside surfaces 6b and 6c. A large number of annular grooves 35a are formed on inside surfaces of the respective covering materials 35 and 36, and a recess and projection surface is formed on the inside surfaces. These annular grooves 35a may be formed in the direction orthogonal to the atmosphere flowing direction, in the parallel direction or even in the oblique direction, and may be formed even in a grid shape.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a booster used for a vehicle brake or the like, and more particularly to a silencer for a booster that reduces intake noise generated when a pressure fluid is introduced into a variable pressure chamber.

[0002]

2. Description of the Related Art Conventionally, as a booster, a cylindrical valve body slidably provided in a shell, an annular first valve seat formed on an inner peripheral surface of the valve body, and a sliding member in the valve body. A freely-fitting valve plunger, an annular second valve seat formed on the valve plunger, and the first valve seat and the second valve seat which are provided in the valve body by the elastic force of a spring.
A valve body seated on the valve seat, a constant pressure passage for communicating an outer side portion of a first seat portion where the first valve seat and the valve body come into contact with a constant pressure chamber defined in the shell, A pressure passage for communicating a portion inside the second seat portion where the second valve seat and the valve body are in contact with each other with a pressure fluid source, and an intermediate portion between the first seat portion and the second seat portion are formed in the shell. A booster having a variable pressure passage communicating with a variable pressure chamber is well known. In the booster having the above-mentioned configuration, when not operating, the valve plunger is retracted so that the valve element is seated on the second valve seat and is separated from the first valve seat. In this state, the second seat portion in which the second valve seat and the valve body are in contact with each other is closed to close the pressure passage in the inner portion thereof.
The first seat portion in which the valve seat and the valve element are in contact with each other is opened, and the constant pressure passage on the outer side of the first seat and the variable pressure passage on the inner side are communicated with each other. As a result, the constant pressure passage communicating with the constant pressure passage and the variable pressure chamber communicating with the variable pressure passage have the same pressure and are in an inoperative state. On the other hand, when the booster is operated, the valve plunger is advanced by depressing the pedal, the valve body is seated on the first valve seat, and the first seat portion is closed to establish communication between the constant pressure chamber and the variable pressure chamber. Cut off. Then, when the valve element is separated from the second valve seat and the second seat portion is opened by the subsequent forward movement of the valve plunger, the pressure passage inside the valve passage communicates with the variable pressure passage on the outer side, so that the pressure fluid is introduced into the variable pressure chamber. As a result, a differential pressure is generated between the constant pressure chamber and the variable pressure chamber, and thereby the booster is operated. By the way, when the booster is operated, that is, when the pressure fluid is introduced into the variable pressure chamber from the pressure passage, intake noise may occur. Therefore, conventionally, a sound absorbing material is provided near the entrance of the pressure passage, and the sound absorbing material provides resistance to the flow of the pressure fluid, thereby reducing the introduction speed of the pressure fluid introduced into the variable pressure chamber to generate intake noise. I was trying to prevent.

[0003]

However, in the above-mentioned sound deadening device, since the sound absorbing material is provided in the pressure passage to give a resistance to the flow of the pressure fluid, the boosting power is increased as compared with the case where the sound absorbing material is not provided. There is a drawback that the responsiveness of the device deteriorates. In view of such circumstances, the present invention provides a silencer for a booster that can reduce intake noise without sacrificing the responsiveness of the booster.

[0004]

That is, according to the present invention, in the booster having the above-described structure, an uneven surface is formed on the inner surface of the variable pressure passage.

[0005]

In the muffler of the booster having the above-described structure, it is confirmed that the uneven surface formed in the variable pressure passage can reduce intake noise as compared with the conventional booster in which the uneven surface is not formed. In addition, since the uneven surface does not give resistance to the flow of the pressure fluid as compared with the sound absorbing material provided in the pressure passage, the responsiveness is not sacrificed.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. In FIG. The valve body 6 is divided into two chambers, a rear chamber 5 and a substantially cylindrical valve body 6 which penetrates the shaft portions of the rear shell 2 and the center plate 3 slidably while being kept airtight by annular seal members 7 and 8, respectively. I am letting you. A front power piston 9 and a rear power piston 10 housed in the front chamber 4 and the rear chamber 5 are connected to the valve body 6, respectively, and a front diaphragm 11 and a rear diaphragm 12 are provided on the rear surfaces of the power pistons 9 and 10. And tensioning the front diaphragm 11 to the front and rear of the constant pressure chamber A
A variable pressure chamber B is formed, and a constant pressure chamber C and a variable pressure chamber D are formed before and after the rear diaphragm 12. A valve mechanism 13 for switching a fluid circuit between the two constant pressure chambers A and C and the two variable pressure chambers B and D is provided in the valve body 6.
The valve mechanism 13 includes an annular first valve seat 14 formed on the inner peripheral surface of the valve body 6 and a valve plunger 15 slidably provided on the valve body 6 inside the annular first valve seat 14. An annular second valve seat 16 formed at the right end portion and a valve body 18 which is seated on both valve seats 14 and 16 from the right side of FIG. 1 by the elastic force of a spring 17 are provided. First above
The space outside the annular first seat portion where the valve seat 14 and the valve body 18 are in contact with each other is formed into a constant pressure chamber A and a constant pressure chamber C via axial constant pressure passages 19 and 19 ′ formed in the valve body 6. The constant pressure chamber A is communicated with the intake manifold of the engine through the negative pressure introducing pipe 20. Further, the second valve seat 16 and the valve body 18 are provided inside the annular first seat portion where the first valve seat 14 and the valve body 18 contact each other.
The space outside the annular second seat part that contacts with, that is, the space between the inner and outer first seat parts and the second seat part is connected to the variable pressure chamber D through the variable pressure passage 21 formed in the valve body 6. The variable pressure chamber D is communicated with the variable pressure chamber B through an axial variable pressure passage 22 formed in the valve body 6.
Is in communication with. Further, the second valve seat 16 and the valve body 1
The space inside the second seat portion, which is in contact with 8, is communicated with the atmosphere as the pressure fluid source through the pressure passage 23, and the filter 24 is provided in the pressure passage 23.
Is provided. Next, the front end of the input shaft 25 is pivotally connected to the right side of the valve plunger 15, and the end of the input shaft 25 is connected to a brake pedal (not shown). On the other hand, a plunger plate 26 and a reaction disc 27 are sequentially arranged on the left side of the valve plunger 15, and the reaction disc 27 is fitted to the right end portion of a push rod 28. The push rod 28
The left end portion of the above is slidably protruded from the shaft portion of the front shell 1 through the seal member 29 so as to interlock with the piston of the master cylinder (not shown).
Further, the valve body 6 has a return spring 30.
Are normally held in the inoperative position shown. The terminal tubular portion 6a of the valve body 6 is projected from the opening of the rear shell 2 to the axial rear side, and the terminal tubular portion 6a projected from the opening is covered with a rubber dust cover 31. The above configuration is the same as the configuration of a conventionally known booster. However, as shown in an enlarged view in FIG. 2, the second valve seat 16 is formed in a spherical shape, and the spherical expansion valve formed in the inner peripheral portion of the valve body 18 is formed in the spherical second valve seat 16. The projecting portion 18a is designed to be seated. Therefore, the annular bulging portion 1 of the second valve seat 16 and the valve body 18 is
Look like contact portion between 8a constitutes a second sheet portion S ₂ described above, the second sheet portion S ₂ radially inward pressure passage 23 becomes as a reference, outside variable pressure passage 21
Has become. On the other hand, the first seat portion S ₁ is formed in an annular shape by the contact portion between the first valve seat 14 and the valve body 18, and the outer side in the radial direction of the first seat portion S ₁ serves as the constant pressure passage 19. The inside is a variable pressure passage 21. The variable pressure passage 21 extends to the front side from between the first seat portion S ₁ and the second seat portion S ₂ .
It is formed by an inner surface 6b having a circular cross section of the valve body 6 extending from the first valve seat 14 toward the front side in the axial direction, and an inner surface 6c having a rectangular cross section extending outwardly from the valve body 6 in the radial direction.
Further, a covering material 35 made of synthetic resin is fitted to the inner surface 6b of the valve body 6 and fixed integrally, and
The inner surface 6c of the valve body 6 also has a covering material 36 made of synthetic resin.
Are fitted and fixed together. These covering materials 35, 3
Numeral 6 is formed in a cylindrical shape having a circular or rectangular cross section in conformity with the shape of the inner surfaces 6b and 6c, and as shown in FIG. As a result, the inner surface is formed into an uneven surface. In the illustrated embodiment, the annular groove 35a is formed in a direction orthogonal to the circulation direction of the atmosphere, but it may be formed in parallel with the circulation direction of the atmosphere, or may be formed obliquely. Alternatively, the uneven surface may be randomly formed. In the above configuration, when the brake pedal (not shown) is stepped on and the input shaft 25 and the valve plunger 15 interlocked with the input shaft 25 are integrally advanced, the valve body 18 is seated on the second valve seat 16. The valve body 18 is seated on the first valve seat 14 of the valve body 6, and the variable pressure passages 21 and 22 are eventually moved.
And the constant pressure passages 19 and 19 'are cut off from each other. When the input shaft 25 and the valve plunger 15 are moved forward, the valve body 18 seated on the first valve seat 14 and stopped moving forward is separated from the second valve seat 16, so that the pressure fluid is compressed. It is introduced from the passage 23 into the variable pressure chambers B and D through the variable pressure passage 21 and the variable pressure passage 22. At this time, since the coating materials 35 and 36 are provided on the inner surfaces 6b and 6c of the variable pressure passage 21 formed in the valve body 6 and the inner surfaces thereof are formed into the uneven surface, when the pressure fluid flows through that portion. The generated intake noise can be reduced. FIG. 4 shows an actual intake sound of the booster of the present invention having the configuration of the above embodiment and a conventional booster in which the coating materials 35 and 36 are omitted and the inner surfaces 6b and 6c are formed smoothly. It is a figure which shows the experimental result which measured. In the figure, the measured values of the booster having the configuration of the present invention are indicated by □, and these measured values □ are connected by a two-dot chain line. Further, the measured values of the booster having the above-mentioned conventional configuration are indicated by ◯, and these measured values ◯ are connected by a solid line. In the figure, when the boosting speed is 50 kgf / c〓 / sec, the intake noise generated by the booster having the configuration of this embodiment is 52.7 dB, whereas the booster having the conventional configuration is The intake noise generated at 53.0 dB. The boost speed is 1
At the time of 00 kgf / c〓 / sec, the booster having the structure of this embodiment has a gain of 55.4 dB, whereas the booster having the conventional structure has a gain of 59.2 dB. Furthermore, the pressure rising speed is 200 and 300 kgf / c〓
/ Sec, the booster having the configuration of the invention is 5
9.7 and 62.0 dB, compared to 64.5 and 65.8 d for boosters with conventional configuration.
It is B. As is clear from the above-described measurement results, the intake noise of the booster having the configuration of the present invention is smaller than the intake noise of the booster having the conventional configuration. Further, in the structure of the present invention, since the sound absorbing material is not used in the pressure passage, excellent responsiveness equivalent to that of the booster having the conventional structure is secured. FIG. 5 shows another embodiment of the present invention. In this embodiment, the inner surfaces 106b, 1b of the variable pressure passage 121 formed in the valve body 106 are formed.
A plurality of stepped portions are formed on 06c to form an uneven surface. The plurality of steps are formed on the valve body 106 by forming a not-shown die for injection-molding the valve body 106 with a synthetic resin, and the die is formed by the valve body 106.
The inner diameter of the step is gradually increased in the extraction direction so that it can be extracted. In the figure, 114 is a first valve seat, 115 is a valve plunger, and 116 is
Is a second valve seat, 118 is a valve element, 119 is a constant pressure passage, 123
Is a pressure passage, and 125 is an input shaft. Also, as shown in FIG. 6, a large number of grooves are formed on the outer periphery of the die in the extracting direction, and as a result, a large number of ribs 206d are formed on the inner surface 206b of the variable pressure passage 221 formed in the valve body 206 along the axial direction of the valve body. It is also possible to form the inner surface 206b at equal intervals in the circumferential direction and thereby form the uneven surface. Further, as shown in FIG. 7, a concavo-convex surface may be formed by directly forming a spiral groove or an annular groove 306d on the inner surface 306b of the variable pressure passage 321 formed in the valve body 306 by cutting, or as shown in FIG. Alternatively, the synthetic resin 406d or the like may be sprayed onto the inner surface 406b of the variable pressure passage 421 formed in the valve body 406 to form the inner surface into an uneven surface. Further, as shown in FIG. 9, the variable pressure passage 52 formed in the valve body 506.
The inner surface 506b of one of the coil springs and the plurality of rings 5
The inner surface may be formed into an uneven surface by press-fitting 06d. In any case, when the uneven surface is formed on the inner surface of the variable pressure passage, it is confirmed that the same effect as the first embodiment is obtained. In each of the above embodiments, the uneven surface is formed on almost the entire inner surface of the variable pressure passage. However, due to the required noise reduction effect, only a part of the inner surface of the variable pressure passage, for example, the above inner surfaces 6b and 6c. Of these, the uneven surface may be formed on only one of them.

As described above, according to the present invention, it is possible to obtain an excellent silencing effect without deteriorating the response of the booster.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part of FIG.

FIG. 3 is an enlarged cross-sectional view of a main part of FIG.

FIG. 4 is a diagram showing measurement results of intake sounds of the product of the present invention and the conventional product.

FIG. 5 is a sectional view showing a second embodiment of the present invention.

FIG. 6 is a sectional view showing a third embodiment of the present invention.

FIG. 7 is a sectional view showing a fourth embodiment of the present invention.

FIG. 8 is a sectional view showing a fifth embodiment of the present invention.

FIG. 9 is a sectional view showing a sixth embodiment of the present invention.

[Explanation of sign]

1 ... Front shell 2 ... Rear shell 6, 106, 206, 306, 406, 506 ... Valve body 6b, 106b, 206b, 306b, 406b, 50
6b ... inner surface 6c, 106c ... inner surface 13 ... valve mechanism 14, 114 ... first valve seat 15, 115 ... valve plunger 16, 116 ... second valve seat 18, 118 ... valve body 118a ... annular swelling portion S ₁ ... first 1 seat portion S ₂ ... second seat portion 19, 19 ', 11
9 ... Constant pressure passage 21, 22, 121, 221, 321, 421, 521
… Variation passages 23, 123 ... Pressure passages 35, 36 ... Coating materials A, C ... Constant pressure chambers B, D ... Transformation chambers

Claims (1)

[Claims] 1. A cylindrical valve body slidably provided in a shell, an annular first valve seat formed on an inner peripheral surface of the valve body, and a valve plunger slidably fitted in the valve body. An annular second valve seat formed on the valve plunger, a valve body provided in the valve body and seated on the first valve seat and the second valve seat by the elastic force of a spring; A constant pressure passage that communicates with a constant pressure chamber defined in the shell at a portion outside the first seat portion in which the first valve seat and the valve body contact each other; and a second seat in which the second valve seat and the valve body contact each other. Booster provided with a pressure passage for communicating a portion inside the portion with a pressure fluid source, and a variable pressure passage for communicating an intermediate portion between the first seat portion and the second seat portion with a variable pressure chamber defined in the shell. In the device, an uneven surface was formed on the inner surface of the variable pressure passage. A silencer for a booster characterized in that