JPH08135586A - Muffler for vacuum pump - Google Patents

Abstract

PURPOSE: To perform echo attenuation of exhaust noise and to reduce a manufacturing cost by a method wherein a muffling case in which a closed muffling chamber is formed is arranged on the upper surface of the exhaust hole of the outer wall surface of the housing of a vacuum pump and a groove is formed in a mating surface with a pump housing on the muffling case side. CONSTITUTION: When air in a housing 22 is discharged through an exhaust hole 21 through drive of a vacuum pump 20, this air flows in a muffling chamber 4 in a muffling case 2. Next air flows through a plurality of grooves 9a formed in the end face of the muffling case 2 mounted on the housing 22 through a packing 8 and flows in a second muffling chamber 5 and consecutively flows through a plurality of communication grooves 9b to the outside. In this case, a part of exhaust noise of air through an exhaust hole 21 is absorbed by a sound absorbing material 10 with which the inner wall of the muffling case 2 is covered. Further, pumping operation is relaxed due to enlargement of a volume when air flows in the muffling case 2 and when air flows through the grooves 9a and 9b, muffling resistance is exerted for noise reduction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a silencer for a vacuum pump, which can be attached to the outer wall surface of a housing of the vacuum pump by being integrally structured with the vacuum pump.

[0002]

2. Description of the Related Art Conventionally, there are various silencers for eliminating the exhaust sound of air from an exhaust hole generated by a pumping action of a vacuum pump. However, in the conventional product, the entire silencer is large in order to improve the sound deadening effect, and when it is attached to the vacuum pump, the space is taken and the appearance is bad. Further, there is known a structure in which one or a plurality of one ends of a silencing case have a silencing pipe projecting from the outside of the housing of the vacuum pump and communicating with the outside air (Actually published 59-13685).
No.). In this structure, the sound deadening effect is good,
The number of parts is large corresponding to the number of pipes, and the joining action between the pipes and the sound deadening case by an adhesive or the like is required, resulting in high cost.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the disadvantages of the above-mentioned prior art, and can be mounted on the outer wall surface of the housing of a vacuum pump so as to be compactly and beautifully integrated with the pump. It is an object of the present invention to provide a silencer that can obtain a large silencing effect with a small silencing resistance without lowering efficiency, and that is easy to manufacture and inexpensive.

[0004]

In order to achieve the above object, in the present invention, there is provided a sound deadening case which covers the upper surface of the exhaust hole of the outer wall surface of the housing of the vacuum pump and forms a sound deadening chamber sealed inside. Provide a communication groove in the sound-absorbing chamber of the sound-absorbing case, one end of which is connected to the outside of the vacuum pump housing and the outside of the vacuum pump housing. The purpose is to achieve this purpose.

[0005]

The air discharged from the exhaust hole of the vacuum pump flows into the muffling chamber of the muffling case while expanding its volume. The air that has flowed into the muffling chamber is discharged to the outside air through one or a plurality of communication grooves provided on the muffling case side and on the contact surface of the muffling case and the housing of the vacuum pump.
At this time, since the expansion and the contraction are continuously performed, the pumping action of the vacuum pump is alleviated, and the exhaust sound is echo-attenuated in the muffling case, so that the muffling action is performed.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3, reference numeral 2 denotes, for example, a rectangular box-shaped silencer case, and inside thereof, a first silencer chamber 4 having a relatively large volume by a partition wall 3 and a second silencer chamber 5 that is relatively small. It is divided into. The bottom portions 6 and 7 are wide open, and the peripheral end faces of the bottom portions 6 and 7 are provided with a packing 8 having sealability, heat resistance, etc., for example, through an exhaust hole 21 of the oilless rotary vacuum pump 20 shown in FIG. The outer wall surface of the peripheral flat housing 22 is closely attached and fixed by screwing or the like. A sound absorbing material 10 is attached to the inner wall of the first sound deadening chamber 4. In this way, the sound deadening case 2 is attached to the vacuum pump 2
When mounted on 0, the inner wall surface of the muffler case 2 and the housing 22
A closed muffling room is formed that is surrounded by the outer wall surface of the.
In the muffler chamber surrounded by the muffler case 2 and the housing 22, one or a plurality of end portions of the muffler case 2 has a communication groove 9 communicating with the outside air outside the housing 22 of the vacuum pump 20. , Provided on the close contact surface of the vacuum pump body on the noise reduction case side. Two communication grooves 9a for communicating the first silencing chamber 4 and the second silencing chamber 5 with each other are provided at the outer peripheral edges on both sides of the contact surface of the silencing chamber.
And the outside air are communicated with each other through the straight communication groove 9b communicating with the outside air from the second chamber. Since the oil-free rotary vacuum pump 20 in the embodiment shown in the drawing generates heat during operation, in order to improve the heat radiation effect of the housing 22, the outside wall surface of the housing 22 and the outside of the sound deadening case 2 described above are used. The wall surface is also provided with a plurality of fins 23 for heat dissipation.

In order to eliminate the exhaust noise of the air exhausted from the exhaust hole 21 of the vacuum pump 20 by using the silencer 1 having the above-described structure, the outer wall surface of the housing 22 around the exhaust hole 21 of the vacuum pump 20 is previously prepared. Is formed into a smooth flat surface, and the sound absorbing case 2 is covered on the outer wall surface of the housing on the upper surface of the flat exhaust hole with the widely opened bottom portions 6 and 7 facing downward, and the peripheral end surface and the partition of the bottom portion are covered. The wall end surface is fixed to the outer wall surface of the housing 22 via the packing 8 by screwing or the like, and the silencer 1 is integrated with the vacuum pump 20 on the upper surface of the exhaust hole 21 of the outer wall surface of the housing 22 of the vacuum pump 20. Put on. After that, the vacuum pump 20 is driven and the exhaust hole 2
When the air inside the housing 22 is exhausted from 1, the exhaust hole 2
The air discharged from 1 passes through the sound absorbing chamber 4 in the sound absorbing case 2 and the widely opened bottom portion 6 of the sound absorbing case 2 communicating with the exhaust hole 21 and flows into the sound absorbing chamber. The air is
From the first silencing chamber 4 through the one or a plurality of grooves 9a provided on the end surface of the silencing case 2 side, which is integrally mounted with the outer wall surface of the housing 22 via the packing 8. It flows into the second silencing chamber 5. Similarly, the exhaust gas is on the side of the muffler case 2 and the muffler case 2 and the housing 22.
Is discharged into the outside air outside the housing 22 through one or a plurality of communication grooves 9a provided on the surface closely attached to the outer wall surface of the housing 22.

The exhaust sound of the air from the exhaust hole 21 generated by the pumping action of the vacuum pump 20 is, of course, partly absorbed by the sound absorbing material 10 attached to the inner wall of the sound deadening case 2. When the air including the exhaust sound flows into the muffling case 2 through the exhaust hole 21, the volume of the air expands, so that the pumping action is mitigated, and when passing through the communication groove 9, the exhaust noise is reduced. It is released and released into the atmosphere. Furthermore, in the case where the inside of the muffling case 2 is divided into a plurality of chambers by the partition wall 3 and these are connected by one or a plurality of grooves as in this embodiment,
By repeating contraction and expansion, the vacuum pump 20
The pumping action of the above is further reduced, and the silencing action is further promoted.

Further, in the above-mentioned embodiment, the sound absorbing material 10 is attached to substantially the entire inner wall surface of the sound absorbing case in order to improve the sound absorbing effect. However, even if the sound absorbing material 10 is not attached, the exhaust hole 21 is provided.
When the air including the exhaust sound discharged from the inside of the sound absorbing chambers 4 and 5 passes through the sound deadening communication grooves 9, the exhaust sound is sufficiently attenuated. Therefore, in some cases, the sound absorbing material 10 is attached to the inner wall surface of the sound deadening case. You don't have to wear it on. Further, in order to prevent air containing exhaust noise from leaking out of the muffling case so that the muffling effect is not diminished, in the above embodiment, packing is provided between the peripheral end surface of the bottom of the muffling case 2 and the outer wall surface of the flat housing 22. 8 is interposed, but if the peripheral end surface of the bottom portion of the muffling case 2 and the outer wall surface of the housing 22 can be satisfactorily adhered and there is no risk of air leaking out of the muffling chamber, the packing 8 is not interposed. Both good. Furthermore, in the case where the vacuum pump 20 that covers the silencer 1 does not generate heat during operation,
Of course, it is not necessary to provide fins 23 for heat dissipation on the outer peripheral wall of the muffling case 2, and the housing 22 portion of the vacuum pump 20 where the muffler 1 is not mounted is sufficient to generate heat during operation of the vacuum pump 20. It is not necessary to provide the fins 23 on the sound deadening case 2 as long as the heat can be dissipated.

[0010]

As described above, since the muffler of the present invention is provided with the groove on the mating surface of the muffler case side with the pump housing, it can be easily manufactured by die molding such as die casting. Manufacturing cost is low. Further, since the vacuum pump can be integrally mounted on the upper surface of the exhaust hole on the outer wall surface of the vacuum pump housing, the silencer can be compactly mounted on the vacuum pump without taking a good space. Further, the muffler of the present invention has a high muffling effect because the muffler uses a method of passing the exhaust gas into the groove, and has a simple structure. Therefore, the muffling resistance is low and the pump efficiency of the vacuum pump is reduced. There is no. Further, by appropriately selecting the inner diameter, the length, and the number of the communication grooves in the silencer, it is possible to construct a silencer having a good silence effect that is suitable for various vacuum pumps.

[Brief description of drawings]

FIG. 1 is a front sectional view of a vacuum pump equipped with a silencer of the present invention.

FIG. 2 is a sectional view taken along line BB of FIG.

FIG. 3 is a bottom view of a muffling case used in the muffler of the present invention.

[Explanation of symbols]

 1 muffler 2 muffler case 3 partition wall 4 first muffler chamber 5 second muffler chamber 6, 7 muffler case bottom 8 packing 9 muffler groove 10 sound absorbing material 20 vacuum pump 21 exhaust hole 22 housing 23 radiating fin

Claims (3)

[Claims] 1. A sound deadening case is provided to cover an upper surface of an exhaust hole of an outer wall surface of a housing of a vacuum pump to form a sealed sound deadening chamber, and one or more of the sound deadening chamber is provided in the sound deadening chamber. A silencer for a vacuum pump, characterized in that a communication groove whose end communicates with the outside air outside the housing of the vacuum pump is provided on the silencer case side and on the contact surface with the vacuum pump body. 2. A partition for partitioning the interior of the muffler case into a plurality of chambers is provided, and a communication groove that communicates between adjacent chambers and a communication groove that is open to the atmosphere in the most downstream chamber are provided on the muffler case side. The silencer for a vacuum pump according to claim 1, wherein the silencer is provided on a surface closely attached to the main body of the vacuum pump. 3. A communication groove for communicating between adjacent chambers is provided at an outer peripheral edge of the sound deadening chamber on the side close to the sound deadening case and in close contact with the vacuum pump body. Vacuum pump silencer.