JPH0632253U - Booster sound absorber - Google Patents

Abstract

(57) [Summary] [Structure] The booster includes a valve body 6 having an end tubular portion 6a protruding from the opening of the shell 2 to the outside, and a dust cover 36 covering the end tubular portion 6a. . The end portion of the dust cover 36 on the atmosphere side is projected to the outside of the end cylindrical portion 6a of the valve body 6, and the sound absorbing material 37 is disposed in the protruding portion 36b, and the sound absorbing material 37 is provided. The filter 38 is provided closer to the shell 2 than the shell 38 is. Further, an air introduction port 36e is formed in the dust cover on the shell 2 side of the sound absorbing material 37. Instead of providing the sound absorbing material 37, the same effect can be obtained by increasing the thickness of the end closing portion 36c of the dust cover. [Effect] An excellent sound absorbing effect can be obtained without impairing the responsiveness.

Description

[Detailed description of the device] [Industrial applications]

 BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a booster, and more particularly to a sound absorber of a booster for reducing intake noise when introducing a pressure fluid into a shell.

[Prior art]

 A booster is generally provided in a shell so as to be reciprocally movable, and has a valve body whose end tubular portion is projected from an opening of the shell to the outside, and a valve mechanism which is housed in the valve body to control opening / closing of a fluid passage. An input shaft that is inserted into the terminal tubular portion and is linked to the valve mechanism, a pressure passage formed between the input shaft and the terminal tubular portion, and a filter provided in the pressure passage. A bellows-shaped dust cover is provided for covering the terminal tubular portion protruding from the opening of the shell to the outside.

[Problems to be solved by the device]

 The above filter not only removes dust in the pressure fluid but also has a function as a sound absorbing material, but there is a drawback that the filter alone does not provide a sufficient sound absorbing effect and generates a large intake noise. . There are various known sound absorbing materials that have a sound absorbing effect superior to that of a filter for removing dust in the pressure fluid, but generally, if the sound absorbing effect is increased, the air permeability decreases and the responsiveness deteriorates. Therefore, a sound absorbing material having an excellent sound absorbing effect could not be used. In consideration of such a situation, the present invention makes it possible to secure an excellent sound absorbing effect and responsiveness at the same time.

[Means for Solving the Problems]

 That is, according to the present invention, in the booster having the above-mentioned configuration, the end portion of the dust cover on the atmosphere side is made to protrude outward from the end cylindrical portion of the valve body, and the sound absorbing material is disposed in the protruding portion. Moreover, the air inlet is provided in the dust cover on the shell side of the sound absorbing material. Alternatively, instead of providing a sound-absorbing material, the atmosphere-side end portion of the dust cover is made to project outward beyond the end cylindrical portion of the valve body to close the end of the protruding portion, and the end closed portion of the end portion is closed. The wall thickness may be set thicker than that of the bellows-like portion of the dust cover, and the air inlet may be formed in the dust cover on the shell side of the end closed portion.

[Action]

 According to the above configuration, the pressure fluid is introduced into the dust cover from the air introduction port, and the dust is removed while flowing through the filter provided in the pressure passage. The intake sound generated during the distribution is absorbed by the sound absorbing material provided in the protruding portion of the dust cover or the thick wall portion of the end closed portion of the dust cover. In any case, since the pressure fluid introduced into the pressure passage does not flow through the sound absorbing material or the like, the response is not deteriorated and the excellent sound absorbing effect can be obtained.

【Example】

 The present invention will be described below with reference to the illustrated embodiment. In FIG. 1, a sealed container constituted by a front shell 1 and a rear shell 2 has a front chamber 4 and a rear chamber, which are located in front of and behind a center plate 3 provided at a central portion thereof. 5, and a substantially cylindrical valve body 6 is slidably pierced through the shaft portions of the rear shell 2 and the center plate 3 by annular seal members 7 and 8 while maintaining airtightness. There is. 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 a constant pressure chamber A and a variable pressure chamber B are formed in front and rear of the front diaphragm 11, and a constant pressure chamber C and a variable pressure chamber D are also formed in front and rear of the rear diaphragm 12, respectively. A valve mechanism 15 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, and the valve mechanism 15 is an annular structure formed in the valve body 6. A first valve seat 16 and an annular second valve seat 18 formed at the right end of a valve plunger 17 slidably provided on the valve body 6 inside the annular first valve seat 16; Both valve seats 16 and 18 are provided with a valve body 20 which is seated by the elastic force of a spring 19 from the right side in FIG. The space on the outer peripheral side of the annular seat portion where the first valve seat 16 and the valve body 20 are in contact with each other is communicated with the constant pressure chamber A through an axial constant pressure passage 23 formed in the valve body 6, and the constant pressure chamber The chamber A is connected to the intake manifold of the engine via the negative pressure introducing pipe 24. Further, the constant pressure chamber A is communicated with the constant pressure chamber C via another constant pressure passage 25 formed in the valve body 6. Further, on the inner peripheral side of the annular seat portion where the first valve seat 16 and the valve body 20 contact each other, on the outer peripheral portion of the annular seat portion where the second valve seat 18 and the valve body 20 contact each other, that is, The space in the middle of the inner and outer annular seat portions is communicated with the variable pressure chamber D via a variable pressure passage 26 formed in the valve body 6 in the radial direction, and the variable pressure chamber D is connected to another variable pressure passage 27 formed in the valve body 6. It is connected to the variable voltage room B via. Further, the space on the inner peripheral side of the inner annular seat portion where the second valve seat 18 and the valve body 20 contact each other is communicated with the pressure passage 28 which communicates with the atmosphere. A right end portion of the valve plunger 17 slidably provided on the valve body 6 is connected to an input shaft 29 linked with a brake pedal (not shown), and a left end portion of the valve plunger 17 is a recess formed at the base of the push rod 30. It faces the right end surface of the reaction disc 31 housed inside. The left end portion of the push rod 30 is slidably projected to the outside from the shaft portion of the front shell 1 via a seal member 32 and is interlocked with a piston of a master cylinder (not shown). Further, the valve body 6 is normally held in a non-actuated position by a return spring 33. A rubber bellows-shaped dust cover 36 that covers the end tubular portion 6a of the valve body 6 has its right end connected to the rear shell 2, and the bellows-like portion 36a of the dust cover 36 is the end tubular portion 6a of the valve body 6. Covers. On the other hand, the left end portion of the dust cover 36, which is the end portion on the atmosphere side, projects toward the rear side by a required amount from the terminal tubular portion 6a, and the right end portion of the projecting portion 36b is bent inward in the radial direction. The end of the protruding portion 36b is closed, and the end closing portion 36c is connected to the input shaft 29 while maintaining airtightness. In the present embodiment, the wall thickness of the protruding portion 36b of the dust cover 36 is slightly thicker than the wall thickness of the other portions, that is, the bellows-shaped portion 36a and the end closing portion 36c, in order to secure the rigidity of the portion. I am doing it. Further, also on the inner surface of the end closed portion 36c, in order to secure the rigidity of the portion, six radial ribs 36d having a width of 1 to 2 mm are formed at circumferentially equidistant positions. Further, a sound absorbing material 37 having a low air permeability but having an excellent sound absorbing effect is disposed on the right side inside the protruding portion 36b of the dust cover 36, and the sound absorbing material 37 on the left side of the sound absorbing material 37, that is, on the rear shell 2 side. An air inlet 36e is formed in the dust cover 36. Further, a filter 38 is arranged in the protruding portion 36b on the left side of the sound absorbing material 37 and in the terminal cylindrical portion 6a of the valve body 6. According to the above configuration, the atmosphere introduced from the air introduction port 36e is introduced into the pressure passage 28 through the filter 38, flows in the pressure passage 28 to the front side, and is supplied to the valve mechanism 15. become. The dust contained in the atmosphere is removed while passing through the filter 38, and the intake sound is absorbed by the sound absorbing material 37 provided axially outside the air inlet 36e. As described above, since the sound absorbing material 37, which is inferior in breathability but has an excellent sound absorbing effect, is provided adjacent to the air circulation path, it is possible to provide such a sound absorbing material in the air circulation path. In addition, the responsiveness is not deteriorated, and the intake noise can be satisfactorily reduced compared to the case where the sound absorbing material 37 is not provided. The sound absorbing effect can be further enhanced by forming irregularities on the end surface of the sound absorbing material 37 on the filter 38 side or by forming a space inside the sound absorbing material 37 that opens to the end surface on the filter 38 side. it can. FIG. 2 shows another embodiment of the present invention. In this embodiment, instead of providing the sound absorbing material 37, the thickness of the end closing portion 36c is set sufficiently thicker than the thickness of the bellows-like portion 36a. The thick end closing portion 36c has the same function and effect as the sound absorbing material 37. As an example, the wall thickness of the bellows-shaped portion 36a is set to 1 mm, while the wall thickness of the end closed portion 36c is set to 3.6 mm. Further, in this embodiment, the thickness of the protruding portion 36b of the dust cover 36 is made equal to the thickness of the terminal closing portion 36c to secure the rigidity of the protruding portion 36b, but the thickness of the protruding portion 36b is increased. However, the sound absorption effect cannot be expected so much. Further, an air inlet 36e is formed in the dust cover 36 on the shell side so as to be adjacent to the end closed portion 36c. FIG. 3 is an experimental result diagram for explaining the effect of the present invention. In this experiment, the average pressurizing speed required to increase the brake fluid pressure from 10 kg / c〓 to 60 kg / c〓 is varied. Then, the intake sound at that time is measured. As the device of the present invention, a brake booster having the same configuration as that of each of the above-described embodiments is used, and as a comparison device, the sound absorbing material 37 is omitted from the device of the present invention of FIG. A brake booster having a reduced axial dimension of the portion 36b was used. As the sound absorbing material 37, a commercially available sound absorbing material was used. In FIG. 3, □ indicates the experimental result of the comparative device, × indicates the experimental result of the proposed device using the sound absorbing material 37, and ◇ indicates the device of the present invention in which the wall thickness of the end closing portion 36c is increased. The experimental results are shown respectively. Then, from these experimental results, lines showing average characteristics are drawn. As can be seen from the experimental results of FIG. 3, when the average pressure rising rate is 300 bar / sec, the comparison device produces an intake sound of 61.7 decibels, whereas the device of the present invention produces an intake sound of 60.5 decibels. , 59.6 decibels. That is, in the device of the present invention, the intake sound can be reduced by more than 1 decibel as compared with the comparison device, and an excellent sound absorbing effect is obtained. Also, no decrease in responsiveness was observed.

[Effect of device]

 As described above, according to the present invention, it is possible to obtain an excellent sound absorbing effect without impairing the responsiveness.

[Brief description of drawings]

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

FIG. 2 is a sectional view of an essential part showing another embodiment of the present invention.

FIG. 3 is an experimental result diagram comparing the sound absorbing effect between the device of the present invention and the comparative device.

[Explanation of sign]

1 ... Front shell 2 ... Rear shell 6 ...
Valve body 6a ... End tubular portion 15 ... Valve mechanism 28
… Pressure passage 29… Input shaft 36… Dust cover 36
a ... Bellows portion 36b ... Projection portion 36c ... End closing portion 36
e ... Air inlet 37 ... Sound absorbing material 38 ... Filter

Claims (2)

[Scope of utility model registration request] 1. A valve body that is reciprocally provided in a shell, and has a distal end cylindrical portion that protrudes from an opening of the shell to the outside; a valve mechanism that is housed in the valve body to control opening and closing of a fluid passage; An input shaft that is inserted into the terminal tubular portion and interlocks with the valve mechanism, a pressure passage formed between the input shaft and the terminal tubular portion, a filter provided in the pressure passage, and an opening of the shell. A booster having a dust cover for covering the end tubular portion projecting outwardly from the outside of the valve body, wherein the atmospheric side end portion of the dust cover is projected outward from the end tubular portion of the valve body and A sound absorbing device for a booster, characterized in that a sound absorbing material is disposed in the dust collecting member, and an air inlet is provided in a dust cover on the shell side of the sound absorbing material. 2. A valve body which is reciprocally provided in a shell and has an end tubular portion protruding from an opening of the shell to the outside; a valve mechanism housed in the valve body to control opening and closing of a fluid passage; An input shaft that is inserted into the terminal tubular portion and interlocks with the valve mechanism, a pressure passage formed between the input shaft and the terminal tubular portion, a filter provided in the pressure passage, and an opening of the shell. In the booster including a bellows-shaped dust cover that covers the terminal tubular portion that is projected to the outside, the atmospheric side end portion of the dust cover is projected outward from the terminal tubular portion of the valve body. The end of the protrusion is closed, and the thickness of the end closed portion is set to be thicker than the thickness of the bellows-like portion of the dust cover, and the air introduction port is provided in the dust cover closer to the shell than the end closed portion. Absorbing device of the booster, characterized in that bored.