JPH0821227A - Exhaust muffler - Google Patents

Abstract

PURPOSE:To provide a muffler for wherein a passage formed between an outer cylinder and an inner cylinder can be completely shut off by using a gas seal made of a heat expansive ceramic material instead of a metallic shielding member, the dimensional precision of the outer cylinder and the inner cylinder can be deceased without deforming the outer cylinder, and also assembly can be easily performed. CONSTITUTION:Gas seals 11 made of a heat expansive ceramic are provided in the positions facing partition plates 5, 6 arranged in a passage 10 formed by the outer peripheral surface of an inner cylinder 2 and the inner peripheral surface of an outer cylinder 3, and also inside the inner cylinder, and exhaust gas to flow and to be bypassed in the passage 10 is shut off by the gas seals 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust silencer for an automobile or the like.

[0002]

2. Description of the Related Art An example of a conventional exhaust silencer is shown in FIG.
This will be described with reference to FIG. In FIG. 2A, a plurality of muffling chambers are formed by a plurality of partition plates inside an inner cylinder 50 which is formed by punching a large number of holes 50a in a metal plate. Figure 2
A part thereof is shown in (a), and the silencing chambers A to C are formed by the partition plates 51 to 53, and the silencing chambers A to C are respectively pipes 54 to 56.
Are connected in series by.

A metal outer cylinder 57 is fitted around the outer circumference of the inner cylinder 50, and corresponds to the partition plates 52 and 53 in a passage 58 formed between the inner cylinder 50 and the outer cylinder 57. A shield member 59 made of metal and formed in a ring shape is fixedly fitted into the inner cylinder 50 by welding or the like over the entire circumference of the passage 58 at the position.

The shield member 59 serves to hold the inner cylinder 50 at a predetermined position with respect to the outer cylinder 57 and to block the exhaust gas flowing through the passage 58. That is, the shielding member 59 can improve the sound deadening effect by bypassing the passage 58 from the sound deadening chamber A and blocking the flow of the exhaust gas which is going to flow directly to the sound deadening chamber C and guiding it to the respective sound deadening chambers. In the passage 58, a sound absorbing material such as glass wool or steel wool or a heat insulating material is provided, and the inner cylinder 50, the outer cylinder 57, and the shielding member 59 are generally formed by molding a metal material such as a steel plate or a stainless steel plate. Is.

[0005]

However, in the above-described conventional exhaust silencer, the outer cylinder 57, the inner cylinder 50, and the shielding member 59 are provided in order to block the flow of the exhaust gas flowing through the passage 58.
It is necessary to secure the dimensional accuracy of the
There is a problem that the processing costs of the 57, the inner cylinder 50, and the shielding member 59 increase. Further, since the outer cylinder 57 and the shielding member 59 are made of metal, it is difficult to obtain perfect airtightness due to a gap for fitting or a gap caused by a difference in thermal expansion coefficient between the two when the exhaust silencer is used. Therefore, there is a problem that the effect of shielding the exhaust gas flowing through the passage 58 and bypassing is not sufficient, and the sound deadening effect is reduced.

Further, when the fitting tolerance between the inner diameter of the outer cylinder 57 and the outer diameter of the shielding member 59 is made small in order to improve the airtightness, the temperature rises when the exhaust silencer is used.
As shown in (b), the shielding member 59 expands in the radial direction and the outer cylinder
There is a risk of locally deforming 57 and reducing the strength of the outer cylinder 57. Further, at this time, there is a problem that the projection 60 corresponding to the shape of the shielding member 59 remains and is exposed on the surface of the outer cylinder 57, and the appearance is impaired.

The exhaust silencer according to the present invention can completely shield the passage between the inner cylinder and the outer cylinder by using the gas seal of the heat-expandable ceramic material instead of the metal shielding member. Another object of the present invention is to provide an exhaust silencer that can reduce the dimensional accuracy of the outer cylinder and the inner cylinder without deforming the outer cylinder and can be easily assembled.

[0008]

An exhaust silencer according to the present invention is an exhaust silencer in which an outer cylinder is fitted on the outer periphery of an inner cylinder, and the outer silencer is formed by the outer peripheral surface of the inner cylinder and the inner peripheral surface of the outer cylinder. A gas seal made of a heat-expandable ceramic material is provided in the formed passage over the entire circumference of the passage, and the gas seal shuts off exhaust gas flowing through the passage. It is an exhaust silencer characterized by.

Further, the exhaust silencer according to the present invention is an exhaust silencer in which an outer cylinder is fitted on the outer circumference of an inner cylinder having a large number of ventilation holes on its side surface, and has a size corresponding to the inner circumference of the inner cylinder. And a partition plate for partitioning the inside of the inner cylinder into a plurality of chambers, and a pipe that penetrates through the partition plate and is connected to connect the plurality of chambers in series to circulate exhaust gas in each chamber. Then, in the passage formed by the outer peripheral surface of the inner cylinder and the inner peripheral surface of the outer cylinder and at a position corresponding to the partition plate, the heat-expandable ceramic material is formed over the entire circumference of the passage. An exhaust silencer, characterized in that a gas seal is provided, and the exhaust gas that flows through the passage is blocked by the gas seal.

[0010]

Since the exhaust silencer according to the present invention is constructed as described above, the airtightness formed of the heat-expandable ceramic material provided in the passage formed by the inner peripheral surface of the outer cylinder and the outer peripheral surface of the inner cylinder. The gas seal having the property thermally expands due to heating when the exhaust silencer is used, and is brought into close contact with the inner peripheral surface of the outer cylinder and the outer peripheral surface of the inner cylinder, whereby the passage can be completely blocked. Therefore, the exhaust gas, which bypasses the passage and does not pass through the muffling chamber, can be blocked and guided to the muffling chamber, and the muffling effect can be improved.

Further, since the heat-expandable ceramic material has a large coefficient of thermal expansion, it absorbs a dimensional error occurring during manufacturing of the inner cylinder and the outer cylinder and an increase / decrease in size due to a difference in thermal expansion coefficient between the inner cylinder and the outer cylinder. The passage can be completely blocked and the inner cylinder can be firmly held at a predetermined position with respect to the outer cylinder. Further, since the heat-expandable ceramic material has appropriate flexibility and elasticity, it is possible to disperse the stress caused by its own thermal expansion in the radial direction of the outer cylinder in the axial direction of the outer cylinder. Therefore, the surface shape of the outer cylinder is not deformed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an exhaust silencer according to the present invention will be specifically described with reference to the drawings. 1 (a) is a cross-sectional explanatory view showing a part of the exhaust silencer of the present invention, and FIG. 1 (b) is a perspective view showing a gas seal made of a heat-expandable ceramic material.

In FIG. 1A, an exhaust silencer body 1
Has a double structure in which the outer cylinder 3 is fitted around the outer circumference of the inner cylinder 2 at a predetermined interval, and a plurality of muffling chambers are formed inside the inner cylinder 2. Further, a not-shown sound absorbing material or heat insulating material such as glass wool or steel wool is provided in a passage 10 which will be described later formed between the inner cylinder 2 and the outer cylinder 3 to enhance the sound deadening effect and prevent heat damage to the outside. It is configured to prevent. The left end 1a of the main body 1 in FIG. 1A is connected to the engine side, and the right end 1b is connected to the exhaust port side that discharges exhaust gas into the atmosphere.

The inner cylinder 2 is formed by punching a large number of holes 2a in a metal plate such as a steel plate or a stainless plate, and has a predetermined diameter. The outer cylinder 3 has a diameter larger than that of the inner cylinder 2, and is configured so as to be airtight as a whole, so that it is possible to maintain the cutoff from the outside air. The surface of the outer cylinder 3 is composed of a steel plate that has been subjected to surface luster treatment such as plating or painting so as to give a beautiful appearance, a stainless steel plate that has been surface-polished, and an aluminum outer cylinder that has been surface-finished.

Inside the inner cylinder 2, a plurality of metal partition plates having a size corresponding to the inner circumference of the inner cylinder 2 are arranged at predetermined intervals, and each is fixed to the inner cylinder 2 by welding or the like. There is. A hole 2a is not formed in the side surface of the inner cylinder 2 corresponding to the position where the partition plate is arranged, so that the inner peripheral surface of the inner cylinder 2 and the partition plate can be connected while maintaining airtightness. Has become.

Further, a predetermined number of pipes are penetratingly connected to the partition plate at a predetermined position, and a plurality of silencing chambers connected in series are constituted by these, and exhaust gas exhausted from the engine is formed. Is introduced into each chamber and sequentially expanded to reduce the exhaust gas temperature to a low pressure and reduce the exhaust noise of the engine.

FIG. 1A shows a part of the exhaust silencer. Partition plates 4, 5 and 6 are fixed to the inner peripheral surface of the inner cylinder 2 at predetermined intervals inside the inner cylinder 2, thereby supporting and reinforcing the inner cylinder 2 in the radial direction and at the same time. The sound deadening chambers A, B, and C are formed inside 2. A large number of holes 4a are formed in the partition plate 4, and the partition plates 5 and 6 are shown in FIG.
As shown in (a), the pipes 7, 8 and 9 are respectively penetrated and connected by welding or the like while maintaining airtightness.

With the above construction, the muffling chambers A to C are provided with pipes 7.
9 to 9 in series, and flows through the hole 4a of the partition plate 4 from the left end 1a connected to the engine side to the muffler chamber A.
The exhaust gas guided to (1) flows through the pipe 7 into the muffling chamber C, further flows through the pipe 8 into the muffling chamber B, further flows through the pipe 9 and is guided to the right end 1b. In this expansion process, the exhaust gas is made low temperature and low pressure, and the exhaust noise of the engine can be silenced. Further, the exhaust gas flows through the hole 2a of the inner cylinder 2 and is also introduced into the passage 10, and the sound deadening effect is further enhanced by glass wool, steel wool, etc. (not shown) provided in the passage 10.

A gas seal 11 made of a heat-expandable ceramic material is provided in a passage 10 formed by the outer peripheral surface of the inner cylinder 2 and the inner peripheral surface of the outer cylinder 3 and at positions corresponding to the partition plates 5 and 6. Are provided so as to shield the passage 10 over the entire circumference thereof. Therefore, the muffling chambers A, B, and B are formed by the partition plates 5 and 6 and the gas seals 11 corresponding to the partition plates 5 and 6, respectively.
Corresponding to C, the passage 10 is divided into 10a, 10b and 10c, respectively, to be shielded.

That is, the muffling chambers A, B, C and the passages 10a, 10
Although b and 10c are configured to allow exhaust gas to flow through the holes 2a of the inner cylinder 2, respectively, the passages 10a, 10b and 10c are shielded from each other, so that exhaust gas flows between the muffling chambers A, B and C by pipes. Only regulated by 7, 8 and 9.

As shown in FIG. 1B, the gas seal 11 has a thickness corresponding to the distance (width of the passage 10) between the outer peripheral surface of the inner cylinder 2 and the inner peripheral surface of the outer cylinder 3 and the inner cylinder 2. The gas seal 11 is configured to have a length corresponding to the entire circumference of the passage 10 formed by the outer circumference and the inner circumference of the outer cylinder 3 and a predetermined width. Fitting parts 11a and 11b formed to fit
Is provided.

The gas seal 11 is made of a heat-expandable ceramic material. The characteristic of this material is that it has airtightness, its volume expands by heating, and it has appropriate elasticity and flexibility. Easy to cut for molding,
It is also a material with excellent heat resistance.

By configuring the gas seal 11 having such properties as described above, the inner cylinder 2 is firmly held at a predetermined position in the outer cylinder 3, and the outer peripheral surface of the inner cylinder 2 and the outer cylinder 3 are held. It is possible to completely block the passage 10 formed by the inner peripheral surface and the sound deadening effect.

That is, when the exhaust silencer is used, the gas seal 11 is heated and expanded by the heat-expanding action and the airtight action of the gas seal 11, and the outer peripheral surface of the inner cylinder 2 and the inner peripheral surface of the outer cylinder 3 are expanded. Stick to and. As a result, the inner cylinder 2 can be firmly held with respect to the outer cylinder 3, and the passage 10 formed in the outer periphery of the muffling chamber A in the passage 10
By maintaining the airtightness between a and the passage 10b formed on the outer periphery of the sound deadening chamber B and the airtightness between the passage 10b and the passage 10c formed on the outer circumference of the sound deadening chamber C, the sound deadening chamber A ，
Bypassing the passage 10 without passing through B and C, the left end 1a
Therefore, it is possible to completely block the flow of exhaust gas that is about to flow from the right end 1b.

Therefore, the exhaust gas flowing through the passages 10a, 10b and 10c can be guided to the silencing chambers A, B and C, respectively, and the silencing effect can be improved. Further, since the gas seal 11 has a relatively large thermal expansion property, the inner cylinder 2,
Since it is possible to absorb a dimensional error that occurs during manufacturing of the outer cylinder 3 and an increase or decrease in size due to a difference in thermal expansion coefficient between the inner cylinder 2 and the outer cylinder 3, it is possible to reduce the dimensional accuracy of the inner cylinder 2 and the outer cylinder 3. Cost can be reduced.

Further, since the gas seal 11 has appropriate elasticity and flexibility, the gas seal 11 is used when the exhaust silencer is used.
Is thermally expanded, the force pressing the outer cylinder 3 outward in the radial direction is dispersed in the axial direction of the outer cylinder 3 according to the rigidity of the outer cylinder 3, so that the outer cylinder 3 is deformed outward in the radial direction. No pressing force is generated. Therefore, unlike the above-described conventional example, the metal shielding member expands in the radial direction due to the temperature rise during use to deform the outer cylinder, and the strength of the outer cylinder is not reduced. Further, the appearance of the exhaust silencer can be maintained without the problem that the projection corresponding to the shape of the shielding member remains and is exposed on the surface of the outer cylinder, and the appearance of the exhaust silencer is not damaged.

Here, when assembling the gas seal 11, the inner cylinder 2 and the outer cylinder 3, first, the gas seal 11 is wrapped around the outer circumference of the inner cylinder 2 and fixed with an adhesive tape or the like, and then both are integrated. Can be fitted into the outer cylinder 3 and assembled. Therefore, unlike the conventional case, the work of fixing the metal shielding member to the inner cylinder by welding is unnecessary, and the assembling work is easy.

In the above embodiment, the exhaust silencer in which the inner cylinder 2 is formed with a large number of holes 2a has been described. However, in another embodiment, in the exhaust silencer using an inner cylinder in which no holes are formed,
The same can be applied to the case where the passage formed between the outer cylinder and the inner cylinder is blocked.

In the above-described embodiment, the inside of the inner cylinder is partitioned by the partition plate, and the exhaust silencer is configured by connecting the silencing chambers arranged in series in series by the pipes. However, as another embodiment, The sound deadening chamber may be formed three-dimensionally (for example, in a labyrinth) inside the cylinder, or each sound deadening chamber formed in the inner cylinder may be a means other than a pipe (for example, a set of wall surfaces forming the main body). It is also possible to connect them by a passage constituted by a combination of passages).

[0030]

Since the exhaust silencer according to the present invention has the above-described structure and function, the passage is formed by the gas seal of the heat-expandable ceramic material provided in the passage formed by the inner cylinder and the outer cylinder. It is possible to completely cut off the flow of exhaust gas that circulates and bypasses, and improve the sound deadening effect.

Since the outer cylinder is not deformed by the thermal expansion of the gas seal, the strength of the outer cylinder can be maintained. Further, unlike the conventional case, there is no possibility that a protrusion corresponding to the shape of the metallic shielding member remains on the surface of the outer cylinder and is exposed, so that the appearance of the exhaust silencer can be maintained.

Further, since the heat-expandable ceramic material constituting the gas seal has a relatively large thermal expansion property, the size due to the dimensional error of the inner cylinder and the outer cylinder and the difference in the coefficient of thermal expansion of the inner cylinder and the outer cylinder during the manufacturing Since it can absorb the increase and decrease of
The dimensional accuracy of the outer cylinder can be reduced, and the processing cost can be reduced. Further, according to the present invention, the welding work for fixing the metallic shielding member to the inner cylinder at the time of assembling the exhaust silencer unlike the conventional case is unnecessary, and the assembling is easy, so that the manufacturing cost can be reduced.

[Brief description of drawings]

1A is a cross-sectional explanatory view showing a part of an exhaust silencer of the present invention, and FIG. 1B is a perspective view showing a gas seal made of a heat-expandable ceramic material.

FIG. 2 is a diagram showing a conventional example.

[Explanation of symbols]

1 ... Main body, 1a ... Left end part, 1b ... Right end part, 2 ... Inner cylinder, 2a ... Hole, 3 ... Outer cylinder, 4-6 ... Partition plate, 4a ... Hole,
7, 8, 9 ... Pipe, 10, 10a, 10b, 10c ... Passage, 11
... Gas seals, 11a, 11b ... Fitting parts, A, B, C ... Silencer chamber

Claims (2)

[Claims] 1. An exhaust silencer in which an outer cylinder is fitted on an outer circumference of an inner cylinder, wherein a passage formed by an outer peripheral surface of the inner cylinder and an inner peripheral surface of the outer cylinder extends over the entire circumference of the passage. An exhaust silencer characterized in that a gas seal made of a heat-expandable ceramic material is provided, and the gas seal blocks the exhaust gas flowing through the passage. 2. An exhaust silencer in which an outer cylinder is fitted on the outer circumference of an inner cylinder having a large number of ventilation holes on its side surface, the exhaust silencer having a size corresponding to the inner circumference of the inner cylinder and the inside of the inner cylinder. A partition plate for partitioning into a plurality of chambers, and a pipe that penetrates through the partition plate and is connected to connect the plurality of chambers in series to allow exhaust gas to flow through each chamber, and the outer peripheral surface of the inner cylinder A gas seal formed of a heat-expandable ceramic material is provided at a position corresponding to the partition plate in a passage formed by the inner peripheral surface of the outer cylinder and the gas. An exhaust silencer, characterized in that it is constructed so that exhaust gas flowing through the passage is blocked by a seal.