JPH07237540A - Silencing device for assistor - Google Patents

Abstract

PURPOSE:To reduce generation of an air intake sound without giving resistance to circulating a pressure fluid and without worsening responsiveness by forming an irregular surface, formed of a plurality of annular grooves along a circumferential direction, in a part in the outside from a seat part of a valve plunger to appear in a pressure change passage. CONSTITUTION:An assistor is used in a brake or the like of an automobile. On the other hand, a silencing device reduces an air intake sound generated in the case of introducing a pressure fluid into a pressure changing chamber. Then in the second valve seat 16 of spherical shape formed in a right end part of a valve plunger 15, an annular swollen part 18a of a valve unit 18 is seated, and the second seat part S, formed of this contact part, is formed in its inside/outside with a pressure passage 23 and pressure changing passage 21. Here in a part in the outside from the second seat part S of the valve plunger 15 to appear in the pressure change passage 21, a plurality of annular grooves 15a are formed along the circumferential direction. By each annular groove 15a, an irregular surface is formed. In this way, giving resistance to circulating the pressure fluid and worsening responsiveness are eliminated, to reduce generation of the air intake sound.

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 a booster having the above-described structure, a circumferential direction is provided in a portion of the valve plunger facing the inside of the variable pressure passage outside the second seat portion. An uneven surface is formed over the entire surface.

[0005]

It has been confirmed that in the silencer of the booster having the above-mentioned structure, the intake noise can be reduced by the uneven surface formed on the valve plunger 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 portion that contacts with, that is, the space between the inner and outer first seat portions and the second seat portion, is transformed through the radial transformation 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. Furthermore, the second valve seat 1
The space inside the second seat portion inside which the valve 6 and the valve body 18 contact each other is communicated with the atmosphere as a pressure fluid source through the pressure passage 23, and the filter 24 is provided in the pressure passage 23. Is provided. Next, the valve plunger 15
The tip of the input shaft 25 is pivotally connected to the right side of the
The end of the input shaft 25 is connected to a brake pedal (not shown). On the other hand, on the left side of the valve plunger 15, the plunger plate 26 and the reaction disc 2 are provided.
7 are sequentially arranged, and the reaction disk 27 is fitted to the right end portion of the push rod 28. The left end portion of the push rod 28 is slidably projected to the outside from the shaft portion of the front shell 1 via a seal member 29 so as to interlock with the piston of a master cylinder (not shown). Further, the valve body 6 is normally held in a non-actuated position by a return spring 30. 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 contact portion between the second valve seat 16 and the annular bulging portion 18a of the valve body 18 has the above-mentioned second seat portion S.
The inner side of the second seat portion S in the radial direction is the pressure passage 23, and the outer side thereof is the variable pressure passage 21. And in this embodiment, the valve plunger 15 is
Further, the variable pressure passage 21 is provided outside the second seat portion S.
A plurality of annular grooves 15 are provided along the circumferential direction in a portion facing the inside.
a is formed, and the concavo-convex surface is formed by the plurality of annular grooves 15a. In the above structure, the brake pedal (not shown) is depressed to input the input shaft 25 and the input shaft 25.
When the valve plunger 15 that is interlocked with the valve body 15 is integrally advanced, the valve body 18 is integrally advanced while being seated on the second valve seat 16, and eventually the valve body 18 of the valve body 6 is moved. The variable pressure passage 2 is seated on the first valve seat 14
The communication between 1 and 22 and the constant pressure passages 19 and 19 'is cut off. And still input shaft 25 and valve plunger 1
5 moves forward, the valve body 18 seated on the first valve seat 14 and stopped moving forward separates from the second valve seat 16, so that the pressure fluid flows from the pressure passage 23 to the variable pressure passage 21 and the variable pressure passage. It is introduced into the variable pressure chambers B and D via 22. At this time, the valve plunger 15 has a second valve body 16
Since the three annular grooves 15a are formed in the outer peripheral portion of the seat portion S, it is possible to reduce the intake noise generated when the pressure fluid flows through that portion. FIG. 3 shows the booster of the present invention having the configuration of the above embodiment and the annular groove 15a.
FIG. 8 is a diagram showing an experimental result of actually measuring an intake sound with respect to a conventional booster in which the part of the valve plunger 15 is formed smooth by omitting the above. In the figure, the measured values of the booster having the configuration of the present invention are indicated by Δ, and these measured values Δ 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. As can be seen from the figure, when the boost speed is 50 kgf / c〓 / sec, the intake noise generated by the booster having the configuration of the present embodiment is 39.58 dB, whereas the conventional configuration has The intake sound generated by the booster having the above-mentioned device was 52.96 dB. Further, when the boosting speed is 100 kgf / c〓 / sec, the booster having the configuration of the present embodiment has 51.18.
In contrast to this, the booster having the conventional configuration was 59.21 dB. Further boost speed is 200
And 300 kgf / c〓 / sec, the booster having the configuration of the invention has 61.79 and 64.23 dB.
In contrast, the booster having the conventional configuration has 64.49 and 65.83 dB. 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, since the sound absorbing material is not used in the structure of the present invention, excellent responsiveness equivalent to that of the booster having the conventional structure is secured. FIG. 4 shows another embodiment of the present invention. In this embodiment, the outer peripheral portion of the valve plunger 115 is formed in a columnar shape with respect to the second valve seat 116, and an annular protrusion is formed in the central portion of the outer peripheral surface. 115a is formed, and the annular protrusion 115a is engaged with an annular groove 135a formed in the inner peripheral surface of the synthetic resin ring-shaped member 135 to integrally fix the ring-shaped member 135 to the outer peripheral portion of the valve plunger 115. is doing. A large number of fin-shaped protrusions 135b are formed on the outer peripheral surface of the ring-shaped member 135 at regular intervals along the circumferential direction. Therefore, in this embodiment, the valve plunger 115 is
A plurality of fin-shaped protrusions 135b along the circumferential direction and gaps between adjacent protrusions 135b on the outer peripheral portion of the outer peripheral surface of the second seat portion 100S facing the inside of the variable pressure passage 121. Thus, the uneven surface is formed. The other structure is the same as that of the first embodiment described above, and the same members are shown with the numbers used in the first embodiment plus 100. Also in the configuration of the second embodiment as described above, substantially the same operational effect as that of the first embodiment is confirmed.

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

FIG. 4 is a sectional view of an essential part showing another embodiment of the present invention.

[Explanation of sign]

DESCRIPTION OF SYMBOLS 1 ... Front shell 2 ... Rear shell 6 ... Valve body 6a ... End tubular part 13 ... Valve mechanism 14 ... First valve seat 15, 115 ... Valve plunger 15a ...
Annular groove 16, 116 ... Second valve seat 18, 118 ...
Valve bodies 18a, 118a ... Annular bulging portions 19, 19 '... Constant pressure passages 21, 22, 121 ...
Transformer passage 23, 123 ... Pressure passage 135 ...
Ring-shaped member 135b ... Protruding portion A, C ... Constant pressure chamber B, D ... Transformer chamber S, 100S ... Second seat portion

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, the valve seat includes the second seat. The portion facing to the transformer passage outside than the noise suppressor of the booster, characterized in that the formation of the uneven surface over the circumferential direction.