JPH075225Y2 - Silencer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a silencer used in a motorcycle or the like.

[Conventional technology]

FIG. 3 shows a conventional structure of the silencer. This silencer has an outer pipe 20 with both ends sealed by lids 21 and 22.
Inside, an inner pipe 23 having a large number of small holes 24 is attached by inserting both ends thereof into the lids 21 and 22, and a sound absorbing material 25 such as glass wool is interposed between the inner pipe 23 and the outer pipe 20. It is configured.

In assembling the silencer, first, the lid 22 to which the tail pipe 26 is fixed is fixed to one end of the outer pipe 20 by welding, and then the thread 23a at the rear end of the inner pipe 23 fixed to the other lid 21 is fixed to the lid 22.
The lid 21 is fitted into the outer pipe 20 by screwing it into the inner surface of, and the lid and the outer pipe are fixed by welding. In this case, in order to prevent gas leakage, a sealing material 27 is interposed between the both lids 21 and 22 and the outer pipe 20 to fit them together.

The assembled silencer is mounted by connecting the mounting flange of the exhaust pipe 28 and the lid 21 with bolts 29.

In this muffler, the exhaust gas sent to the inner pipe 23 enters the inside of the sound absorbing material 25 through the small holes 24, and the sound absorbing material 25
After being silenced at, it is discharged from the tail pipe 26.

[Problems to be solved by the device]

By the way, since the exhaust gas contains a large amount of water, oil, carbon, etc., if the silencer using the sound absorbing material as described above is used for a long period of time, the sound absorbing material will be removed by the water, oil, etc. of the exhaust gas. Sound absorption performance deteriorates due to clogging. When high-speed exhaust gas flows into the sound absorbing material thus clogged, the muffler may resonate with the flow of exhaust gas and emit abnormal noise. Therefore, the muffler provided with the sound absorbing material requires a new replacement of the sound absorbing material when used for a required period.

However, in the silencer having the conventional structure shown in FIG. 3, since the respective parts are integrally fixed by welding, the sound absorbing material cannot be easily removed. Therefore, when the sound absorbing material is clogged, There is a problem that it is uneconomical in cost because it is necessary to replace the silencer itself.

Further, in the muffler having the above structure, it is necessary to fit the lids 21 and 22 and the outer pipe 20 with the seal material 27 interposed during assembly, so that the assembly work takes time and the seal material is used during assembly. 27 is often cut and attached at the end portion of the outer pipe 20 and the like, which is disadvantageous in that the hermeticity tends to vary.

Furthermore, the muffler is lighter in weight and has better manufacturability.
The outer pipe 20, the inner pipe 23, and the lids 21 and 22 are made of an aluminum alloy of the same material, but the exhaust gas is introduced into the inner pipe 23 to be heated to a high temperature, and the outer pipe is cooled by coming into contact with the outside air. A great difference occurs in the amount of expansion from the outer pipe 20 due to thermal expansion.

However, in the conventional silencer, the outer pipe 20 and the inner pipe
Since both ends of 23 are integrally fixed by the lid plates 21 and 22, the difference in expansion between the two pipes causes a squeeze between the two pipes, which causes strain in the pipes and sometimes cracks on the surface of the pipes. There was a drawback that caused.

Therefore, an object of the present invention is to provide a muffler that is easy to assemble, allows easy replacement of the sound absorbing material, and does not cause distortion due to the difference in thermal expansion of the pipes.

[Means for Solving the Problems]

In order to solve the above-mentioned subject, this invention is an outer pipe,
A flange plate formed of a cylindrical material having one end open and an end plate at the other end, one end of the inner pipe having an outer circumference fitted to the inner diameter of the outer pipe, and the other end fitted to the open end of the outer pipe Attaching bottom cylindrical lids respectively, project the end of the inner pipe from the flange plate by a predetermined amount, and form a screw hole in the flange plate, and project the end of the inner pipe onto the end plate of the outer pipe. A fitting hole for fitting and a bolt insertion hole corresponding to the screw hole are provided, and the inner peripheral surface of the fitting cylindrical portion of the lid is a finished surface by machining, and the flange plate is an end plate of the outer pipe. The structure is such that there is a gap between the open end of the outer pipe and the inner surface of the bottom plate of the lid when the inner pipe is in contact with the inner surface.

[Action]

In the muffler having the above structure, when the flange plate is fitted inside the outer pipe and brought into contact with the end plate, the protruding end portion of the inner pipe is fitted into the fitting hole of the end plate and the outer pipe is opened. The inner pipe is supported in place inside the outer pipe by the fitting of the end and the lid over it.

In the above state, when bolts are screwed into the screw holes of the flange plate from the exhaust pipe and tightened, the end plate of the outer pipe is crimped to the flange plate, so that the outer pipe and the inner pipe are fixed.

In this silencer, the outer pipe and the inner pipe can be separated by removing the bolts, so that the sound absorbing material can be easily replaced.

Further, one end of the outer pipe is integrally closed by the end plate, and the other end is fitted with the fitting cylindrical portion of the lid for sealing, so that a sealing material is required and the assembly is easy. In this case, gas leakage from the fitting portion can be prevented by finishing the fitting cylindrical portion of the lid into a shape that fits with the outer diameter surface of the outer pipe with almost no clearance by machining.

Furthermore, when a difference in the amount of expansion occurs between the outer pipe and the inner pipe due to thermal expansion, the difference in expansion is sucked in the gap between the open end of the outer pipe and the lid. For this reason, the two pipes do not come into contact with each other and no strain occurs.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

As shown in the figure, the outer pipe 1 is formed of a cylindrical material having one end opened and an end plate 2 provided at the other end, and the end plate 2 is fitted with an inner pipe 5 described later in a central portion thereof. The hole 3 is attached, and two bolt insertion holes 4 are formed on both sides of the fitting hole 3.

The inner pipe 5 has a large number of small holes 6 provided on the peripheral surface of a hollow pipe, and a disc-shaped flange plate 7 is integrally fixed to the tip end by welding and a bottomed cylindrical lid 8 is fixed to the rear end. Has been done. The tip of the inner pipe 5 is a projecting end 5a that slightly projects from the end face of the flange plate 7, and the rear end of the inner pipe 5 bends slightly after penetrating the lid 8 to form a tail pipe. Is forming.

The flange plate 7 is formed such that the outer diameter fits into the inner diameter surface of the outer pipe 1, and the end surface has two screw holes 9 and 9 corresponding to the bolt insertion holes 4 of the outer pipe 1. Has been formed.

As shown in FIG. 1, the cover plate 8 is formed by connecting the flange plate 7 to the outer pipe 1.
The inner surface of the end plate 2 is positioned such that a gap 10 is formed between the inner surface of the bottom plate 8a and the open end of the outer pipe 1, and the inner surface of the fitting cylindrical portion 8b is turned or the like. Is machined to a size that fits into the outer diameter surface of the outer pipe 1 with almost no gap.

Further, a sound absorbing material 11 is attached between the inner pipe 5 and the outer pipe 1. The sound absorbing material 11 is made of a porous material such as glass wool and asbestos that can sufficiently withstand high temperatures.

To assemble the silencer having the above structure, first, the inner pipe 5
The flange plate 7 is inserted into the outer pipe 1 in a state where the sound absorbing material 11 is wound around the outer periphery of the outer pipe 1, and the protruding end portion 5a of the inner pipe 5 is fitted into the fitting hole 3 of the outer pipe 1. The inner surface of the plate 2 and the flange plate 7 are brought into contact with each other. In this state, the lid 8 is fitted into the open end of the outer pipe 1, so that the outer pipe 1 is sealed by the lid 8 and the end plate 2.

Then, bolt 13 inserted from the flange of exhaust pipe 12,
When the end plate 2 is inserted and screwed into the screw hole 9 of the flange plate 7, the end plate 2 and the flange plate 7 are crimped, so that the outer pipe 1 and the inner pipe 5 are integrally fixed.

When replacing the sound absorbing material 11, the bolt 13 is removed, the flange plate 7 and the end plate 2 are separated, and the inner pipe 5 is removed from the outer pipe 1. Thereby, the sound absorbing material 11 can be pulled out to the outside.

In the above structure, the outer pipe 1 is formed by crimping the end plate 2 and the flange plate 7 and fitting the outer diameter of the outer pipe 1 and the lid 8.
To prevent leakage of the exhaust gas introduced. In this structure, when the exhaust gas is introduced into the outer pipe 1 from the exhaust pipe 12, the exhaust gas filled in the pipe has no gap due to the characteristics of the fluid flowing in the direction in which the flow passage resistance is small. Does not flow to the crimping part or the fitting part with a large
It flows into the inner pipe 5 having a small flow resistance and is discharged to the outside. Even in the case of mechanical crimping or fitting as described above, by making the gap of crimping or fitting extremely small, gas leakage can be almost eliminated, and noise generated by leaking gas can be reduced. .

Further, since the outer pipe 1 and the inner pipe 5 are not connected at one end by the gap 10, the both pipes 1 and 5 can freely expand and contract independently. Therefore, even if there is a difference in the amount of thermal expansion between the two pipes 1 and 5, the difference is absorbed by the gap 10, and the two pipes do not have a state of interference as in the conventional structure. Therefore, the pipes 1 and 5 are not distorted, and cracks and the like are prevented from occurring.

The inner pipe 23 of the conventional structure shown in FIG. 3 is screwed and fixed to the cover plate 22 and is integrally molded by aluminum die casting, but the aluminum alloy by die casting is weak in strength, thermal expansion and mechanical. 23
There is a drawback that it is easily damaged from a etc. On the other hand, as in the above embodiment, the inner pipe 5 is inserted into the lid 8 to integrally form the tail pipe, and the aluminum pipe for extraction such as 52S is formed by machining. In addition to the fact that cracks are not generated from the threaded portion, the strength is improved and damage accidents can be effectively eliminated.

[Effect of device]

Since the invention is constructed as described above and the outer pipe and the inner pipe can be separated by the bolts, the sound absorbing material can be easily replaced, and the silencer can be used stably.

In addition, the outer pipe and the lid are not sealed with a sealing material,
Since the mechanical crimping and fitting structure is adopted, there are advantages that the assembly is easy, the number of parts can be reduced, and the cost can be reduced.

Furthermore, since the outer pipe and the inner pipe have a structure in which a gap is provided at one end and they are not integrally connected, even if a difference in the thermal expansion amount occurs between the two pipes, the pipes are not distorted and cracks are generated. It has the effect of preventing the occurrence.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view showing an embodiment, FIG. 2 is an exploded perspective view thereof, and FIG. 3 is a partial vertical sectional side view showing a conventional example. 1 ... Outer pipe, 2 ... End plate, 3 ... Fitting hole, 4 ... Bolt insertion hole, 5 ... Inner pipe, 6 ... Small hole, 7 ... Flange plate, 8 ... Lid, 9 …… Screw hole, 10 …… Gap, 11…
… Sound absorbing material.

Claims (1)

[Scope of utility model registration request] 1. A silencer in which an inner pipe having a large number of small holes on its surface is inserted through a sound absorbing material into an outer pipe whose both ends are hermetically sealed, wherein the outer pipe has one end open and the other end. A cylindrical plate with a bottom, which is formed of a cylindrical material having an end plate at its outer end, and a flange plate whose outer circumference fits to the inner diameter of the outer pipe at one end of the inner pipe and whose outer end fits at the open end of the outer pipe. And projecting the end of the inner pipe by a predetermined amount from the flange plate, forming a screw hole in the flange plate, and fitting the protruding end of the inner pipe to the end plate of the outer pipe. A bolt insertion hole corresponding to the dowel hole and the screw hole is provided, the inner peripheral surface of the fitting cylindrical portion of the lid is a finished surface by machining, and the flange plate abuts the inner surface of the end pipe of the outer pipe. In this condition, leave a gap between the open end of the outer pipe and the inner surface of the bottom plate of the lid. Muffler, wherein a set to allow.