JP2513317Y2 - Variable volume silencer - Google Patents

Description

FIELD OF THE INVENTION This invention relates to a muffler, in particular a muffler connected to the intake or exhaust pipe of an engine of a motor vehicle.

2. Description of the Related Art For example, as shown in Japanese Utility Model Publication No. 61-9174, by connecting a box body to an intake pipe of an engine and moving the box body to change the insertion degree of a communication pipe into the box body, A muffler for adjusting the resonance frequency is known. Also,
As shown in U.S. Pat. No. 4,546,733, a resonator is known in which the cross-sectional area of the communication passage between the intake pipe and the resonance chamber is controlled by electrical means in accordance with the engine speed.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention By the way, in the above-mentioned conventional silencer, there has not been proposed a silencer capable of attenuating the intake sound or the exhaust sound continuously corresponding to the engine speed and having a simple structure. For example,
The silencer disclosed in Japanese Utility Model Publication No. 61-9174 has a structure in which the box body is manually moved. Also, U.S. Pat.No. 4,546,73
The resonator disclosed in Japanese Patent No. 3 is a silencer that detects the number of revolutions of an engine by electrical means and operates an on-off valve for air noise having a plurality of specific frequencies. Therefore, the conventional silencer cannot attenuate the intake sound or the exhaust sound continuously corresponding to the engine speed.

Therefore, the present invention solves the above-mentioned drawbacks and provides a variable volume type silencer that can attenuate intake noise or exhaust noise continuously corresponding to the engine speed and has a simplified structure. The purpose is to do.

Means for Solving the Problems A variable volume silencer according to the present invention comprises a silencer body connected to an exhaust pipe or an intake pipe of an engine, a partition slidably arranged in the silencer body, and an intake air of the engine. It has a pressure response device operated by pressure and a connection mechanism that connects the partition wall and the pressure response device. The coupling mechanism has a link mechanism that magnifies the displacement of the diaphragm provided in the pressure response device and transmits the displacement to the partition wall.

Action Pneumatic action based on a change in intake pressure of the engine is utilized to detect a change in engine speed by the pressure response device. The diaphragm provided in the pressure response device expands the displacement of the diaphragm via the link mechanism of the coupling mechanism by the link mechanism, and moves the bulkhead in the silencer body,
Thus, the volume in the silencer body can be automatically changed by the mechanical structure in response to the fluctuation of the intake pressure of the engine.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. First, as clearly shown in FIG. 1, a variable volume silencer 10 of the present invention is a silencer main body having an inlet 11 connected to an exhaust pipe or an intake pipe of an engine (not shown).
12 and a bulkhead 13 slidably arranged in the silencer body 12
And a pressure response device operated by the intake pressure of the engine
14, a connecting mechanism 15 for connecting the partition wall 13 and the pressure response device 14
And The silencer body 12 has a substantially cylindrical cross section, and is coaxially provided with an outlet 16 facing the inlet 11. Pipes 17 and 18 are provided at the inlet 11 and the outlet 16, respectively. A plurality of openings 19 are formed in the pipes 17 and 18, respectively. However, the openings 19 may be entirely removed or the number of the openings 19 may be increased if necessary. A gap 20 is formed between the pipes 17 and 18 to form an air expansion part.

The partition wall 13 has a substantially annular cross section, and slidably contacts the inner wall 12a of the silencer body 12 and the outer wall 18a of the pipe 18 constituting the outlet 16. The outer peripheral portion 13a and the inner peripheral portion 13b of the partition wall 13 are provided with packings 21 and 22, respectively, and the inner wall of the silencer body 12 respectively.
12a and the outer wall 18a of the pipe 18 are in airtight contact. Partition
The reference numeral 13 includes a connection mechanism 15 that extends outward from the silencer body 12.
One end of a pair of links 23 constituting the above is attached. The other end of the link 23 is pivotally attached to one end of the link 25 by the shaft portion 24. The link 25 is rotatably supported by a shaft portion 26, and the other end of the link 25 is connected to one end of a ram 27 of the pressure response device 14. The coupling mechanism 15 is provided with links 23 and 25 as a link mechanism that expands the displacement of the pressure response device 14 and changes the displacement direction. The other end of the ram 27 extends into the case 28 of the pressure response device 14 and is connected to the diaphragm 29. A first pressure chamber 30 and a second pressure chamber 31 separated by a diaphragm 29 are formed in the case 28. The first pressure chamber 30 is provided with a hole 32 that communicates with the outside air, and has a port 35 that is connected to an intake pipe 34 of the engine via an opening / closing valve 33.

The on-off valve 33 includes a case 36, a valve body 37 slidably arranged in the case 36, and a spring 38 for urging the valve body 37 to a comfortable valve position.
And The on-off valve 33 is operated in response to the intake pressure of the engine, and gives the pressure supplied to the pressure response device 14 a desired operating characteristic. For example, the on-off valve 33 is a pressure responsive device 14
The ram 27 can be linearly displaced with respect to the change of the intake pressure of the intake pipe 34 of the engine by giving a linear characteristic to the.

On the other hand, in an air vibration system, it is known that the resonance frequency is inversely proportional to the square root of the volume of the silencer. In the above configuration, when the engine speed is low, the intake pressure generated in the intake pipe 34 is small. Therefore, a low negative pressure is generated in the first pressure chamber 30 via the opening / closing valve 33. Therefore, the ram 27 hardly moves and the volume inside the silencer main body 12 is maintained in a large state, so that the silencer main body 12 largely attenuates low-frequency vibration noise. Conversely, when the engine speed is high, the intake pressure generated in the intake pipe 34 is large. Therefore, a high negative pressure is generated in the first pressure chamber 30 via the opening / closing valve 33. Therefore, the ram 27 moves with a large stroke,
The partition wall 13 is moved to the left side in the figure to reduce the volume inside the silencer body 12. Therefore, the muffler body 12 largely attenuates high-frequency vibration sound. As described above, in the variable volume silencer of the present invention, the pressure response device 14 can detect the change in the intake pressure of the engine by utilizing the pneumatic action of the intake pressure of the engine. The pressure response device 14 for detecting the fluctuation of the engine speed moves the partition wall 13 in the silencer body 12 through the coupling mechanism 15, whereby the silencer body 12 is responded to the fluctuation of the intake pressure of the engine. The volume inside can be changed automatically.

Various modifications can be made to the above embodiment of the present invention.
For example, as shown in FIG. 2, it is possible to connect the pipes 17 and 18 and use a single pipe 39 having an opening 19.

In addition, the invention is to expand the gas or air flowing into the silencer body rapidly to reduce the pressure, and to expand the silencer to expand the silencer, and to install a predetermined volume next to the gas pipe such as an intake pipe or an exhaust pipe. A resonance silencer with a resonator attached to it, gas pipes such as an intake pipe or an exhaust pipe are provided with bypass pipe lines of different lengths, and when the gas encounters through the two pipes, sound waves with a phase shift are generated. The present invention can be applied to various silencers such as an interference silencer that produces a silencing effect by causing interference, or an absorption silencer loaded with a sound absorbing material.

It is also possible to use a connecting mechanism without the on-off valve 33 or a link mechanism. Further, the muffler body 12 and the partition wall 13 can have various shapes.

Effect of the Invention In the variable volume type silencer of the present invention, since the pneumatic action of the intake pressure of the engine is used, the volume inside the silencer body is adjusted by the simple air pressure mechanism in response to the variation of the intake pressure of the engine. It can be changed automatically. Therefore, the intake noise or the exhaust noise can be attenuated continuously with the engine speed by a simple noise reduction mechanism.

[Brief description of drawings]

FIG. 1 is a sectional view of a variable volume silencer according to the present invention, and FIG. 2 is a partial sectional view of a variable volume silencer showing another embodiment of the present invention. 10 …… Variable volume type silencer, 12 …… Silencer body, 13
...... Partition, 14 ...... Pressure response device, 15 ...... Coupling mechanism,

Claims (1)

(57) [Scope of utility model registration request] 1. A muffler body connected to an exhaust pipe or an intake pipe of an engine, a partition wall slidably disposed in the muffler body, a pressure responsive device operated by the intake pressure of the engine, and a partition wall. A variable volume silencer having a coupling mechanism for coupling with a pressure response device, wherein the coupling mechanism has a link mechanism for expanding displacement of a diaphragm provided in the pressure response device and transmitting the displacement to a partition wall. Volume type silencer.