JPS6347613Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an improvement of a flexible joint used for connecting exhaust pipes of automobiles, etc.

[Conventional technology]

As is well known, the exhaust pipe attached to an automobile engine is directly subjected to engine vibration and driving vibration, so if a rigid joint is used when connecting the exhaust pipe, the stress due to vibration will be concentrated on the joint. However, this can lead to damage, functional deterioration, and even malfunction.

Therefore, in order to prevent such problems, conventionally, as shown in Fig. 1, a flexible joint a made of a thin metal tube formed into a bellows shape has been used to connect the exhaust pipe. is used to absorb engine vibrations and driving vibrations transmitted to exhaust pipes b and c.

However, according to this flexible joint a, the exhaust gas G flowing in the pipes b and c collides with the valley d of the flexible joint a, causing turbulence, which causes secondary noise. or become back pressure and reduce the fluidity of exhaust gas G.
This caused a reduction in engine output.
Furthermore, among the plurality of valleys d of the flexible joint a to which this high heat is directly blown, especially the valleys d and d located at both ends are affected by this high heat and are adjacent to the exhaust pipes b and c. Therefore, exhaust pipes b and c
There was a problem that cracks were particularly likely to occur because they received the most force from displacement and vibration. Furthermore, the flexible joint a has the disadvantage that it is weaker than a normal exhaust pipe and is easily cracked by stones thrown by tires when the vehicle is running.

Therefore, in order to prevent heat damage to the troughs of the flexible outer tube due to the blowing of exhaust gas, one end of the flexible outer tube is fixed to one end of the flexible outer tube, and the other end is set as a free end. Japanese Utility Model Publication No. 52-25534 discloses an idea in which an exhaust gas conducting inner pipe is installed nearby.

[Problem that the invention attempts to solve]

However, even with such prior art, cracks still occur in the flexible outer tube due to flying stones and the like because no means are provided to protect the flexible outer tube from flying stones and the like. In addition, since the exhaust gas conducting inner pipe was formed of a metal tube and did not have flexibility, when the exhaust pipe was displaced and the flexible outer pipe was bent, the exhaust gas conducting inner pipe could not be bent. Furthermore, when the exhaust gas conducting inner pipe interferes with the exhaust pipe due to the deformation, stress is concentrated on the exhaust gas conducting inner pipe, resulting in damage to the exhaust gas conducting inner pipe.

[Purpose of invention]

Therefore, the present invention provides a flexible joint for an exhaust pipe that can solve the above-mentioned problems at once.

[Means for solving problems]

In order to achieve this purpose, the present invention includes a flexible outer tube formed from a thin metal tube into a bellows shape,
A flexible protection tube attached to the outside of the flexible outer tube so as to cover its periphery, and a flexible protection tube installed inside the flexible outer tube with one end fixed to one end of the flexible outer tube and the other end being a free end near the other end of the flexible outer tube. In a flexible joint for an exhaust pipe consisting of an exhaust gas conducting inner pipe located at a The free end side of the exhaust gas-conducting inner pipe is arranged slightly farther from the other part of the flexible outer pipe and further downstream than the trough at the end of the flexible outer pipe.

[Effect of invention]

According to the present invention, as the flexible outer tube etc. is bent, the exhaust gas conducting inner tube is also bent accordingly.

[Example of idea]

Hereinafter, an embodiment of the present invention will be described based on FIG. 2.

The flexible joint 1 of this embodiment includes a flexible outer tube 2 formed from a thin metal tube into a bellows shape,
A flexible protective tube 3 provided to cover the flexible outer tube 2; a protective collar 4 provided for fixing the flexible outer tube 2 and the flexible protective tube 3 by spot welding at both ends; 5, an expansion type attachment tube 6 fixed to one end of the flexible outer tube 2 together with the flexible protective tube 3 by spot welding, and this attachment tube 6.
It is fixed by spot welding using a protective collar 8 to the free end 7 portion, and the other end is set as a free end, slightly away from the end of the flexible outer tube 2, and downstream from the trough 15 of the end. It is constituted by an exhaust gas conducting inner pipe 9 located in the exhaust gas passage.

In this embodiment, the flexible protection tube 3 and the exhaust gas conduction inner tube 9 each consist of a strip-like element formed by arranging a large number of fine metal wires (for example, fine stainless steel wire) in parallel. It is constructed by stockinette knitting. Therefore, the flexible protection tube 3 and the exhaust gas communication inner tube 9 have flexibility, and can be deformed in response to an external force when applied thereto. Note that when no external force is applied to the single-supported exhaust gas conducting inner pipe 9, it is bent and its free end becomes the flexible outer pipe 2.
It is formed with enough strength to prevent it from coming into contact with the top. By the way, the protective tube 3 and inner tube 9 are as follows:
The present invention is not limited to this embodiment, and may be directly knitted with stockinette without creating a large number of fine metal wires and band-like elements. Further, the material is not limited to stainless steel wire, and the weaving method and material can be modified in various ways to obtain flexibility depending on the application. A protective collar 10 is fixed to the free end of the exhaust gas conducting inner pipe 9 by spot welding to prevent the material from deforming due to heat or wear.

To use this flexible joint 1, as shown in the figure, the rear end of the upstream exhaust pipe 11 is hermetically fitted into the mounting pipe 6, and the front end of the downstream exhaust pipe 12 is hermetically fitted into the flexible outer pipe 2. After fitting, continuous welding 13 and 14 are applied to fix them.

Therefore, with this flexible joint 1,
The upstream and downstream exhaust pipes 11 and 12 are connected, and the exhaust gas G flowing inside the upstream exhaust pipe 11 is passed through the mounting pipe 6 and the exhaust gas conducting inner pipe 9 to the flexible outer pipe as shown in the arrow. The flow is not affected by the troughs 15 of No. 2 and flows into the exhaust pipe 12 on the downstream side.

In addition, even if vibrations or stress from the engine and during driving transmitted to the upstream and downstream exhaust pipes 11 and 12 are applied to the flexible joint 1, it is absorbed and reduced by the flexibility of the flexible outer pipe 2, and the flexible protection Combined with the fact that the tube 3 absorbs and reduces such vibrations and stress, the flexible outer tube 2 is no longer damaged. Further, according to this embodiment, the flexible protection tube 3 protects the flexible outer tube 2 from flying stones, etc., and when the flexible joint 1 is bent, the exhaust gas conducting inner tube 9 is also bent accordingly. Therefore, as before, the exhaust pipe 1
1 and 12 are displaced and the flexible outer tube 2 etc. are bent, the exhaust gas conducting inner tube 9 may become an obstacle to the bending, and the stress caused by the deformation may be concentrated on the exhaust gas conducting inner tube 9. Everything was gone.

According to this embodiment, part of the exhaust gas G flows into the flexible outer tube 2 from the free end portion of the exhaust gas conducting inner tube 9;
is arranged downstream from the trough 15 at the downstream end of the
Since the exhaust gas G does not directly blow onto the valley 15, cracks do not occur in the valley 15. Furthermore, according to this embodiment, the exhaust pipe 12 on the downstream side can be easily inserted, and since the free end of the exhaust gas conducting inner pipe 9 is not inserted into the exhaust pipe 12 on the downstream side, it is easy to insert the exhaust pipe 12 on the downstream side. Even if the exhaust gas conducting inner pipe 9 swings due to vibration or the like, the free end portion no longer comes into contact with the exhaust pipe 12 and generates noise.

Incidentally, the flexible joint for an exhaust pipe according to the present invention is not limited to the structure of the embodiment. For example, the structure for protecting the fixed end and free end portions of the exhaust gas-conducting inner pipe can be changed to the structure shown in FIGS. 3 to 8. Various changes may be made to the design of the other configurations without departing from the technical idea set forth in the claims of the utility model registration.

[Effect of idea]

As described above, according to the present invention, since the exhaust gas flows through the exhaust gas conducting inner pipe, it goes without saying that there is no heat effect on the flexible outer pipe of the exhaust gas, and there is no vibration or vibration during driving. Even if stress is applied to the flexible joint, it will be absorbed and reduced by the flexibility of the flexible outer tube, and the flexible protection tube will also absorb and reduce such vibration and stress. Protection has become more secure. Furthermore, since the flexible outer tube is covered with the flexible protective tube, it is possible to prevent the occurrence of cracks in the flexible outer tube due to flying stones or the like.
Furthermore, as the flexible joint bends, the exhaust gas conduction inner pipe also bends, so when the exhaust pipe is displaced and the flexible joint is bent, the exhaust gas conduction inner pipe is bent. This eliminates the possibility of hindrance to bending or the concentration of stress caused by deformation on the exhaust gas-conducting inner pipe. Furthermore, the free end of the exhaust gas conducting inner pipe is arranged downstream of the valley at the downstream end of the flexible outer pipe, and the exhaust gas does not blow directly into the valley. No cracks will occur. In addition, it is easier to insert the exhaust pipe on the downstream side, and since the free end of the inner exhaust gas pipe is not inserted into the exhaust pipe on the downstream side, the inside of the exhaust gas pipe may be damaged due to vibrations when the vehicle is running. Even if the pipe vibrates, the free end portion will not come into contact with the exhaust pipe and generate noise.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional view showing a flexible joint of an exhaust pipe with a conventional structure, Fig. 2 is a longitudinal sectional view of an embodiment of the present invention, and Figs. It is a longitudinal cross-sectional view showing a modification of the protection structure of the end and free end portion. 1... Flexible joint, 2... Flexible outer pipe, 9... Exhaust gas conduction inner pipe, 10... Protective collar.

Claims (1)

[Scope of utility model registration request] A flexible outer tube formed by forming a thin metal tube into a bellows shape, a flexible protective tube attached to the outside of the flexible outer tube so as to cover the circumference thereof, and a flexible outer tube installed inside the flexible outer tube with one end attached to one end of the flexible outer tube. In a flexible joint for an exhaust pipe consisting of an exhaust gas conducting inner pipe that is fixed and the other end is a free end and the exhaust gas conducting inner pipe is positioned near the other end of the flexible outer pipe, the exhaust gas conducting inner pipe is made of a large number of fine metal wires. The free end side of this exhaust gas conducting inner tube is slightly away from the end of the flexible outer tube, and further from the trough at the end of the flexible outer tube. A flexible joint for an exhaust pipe, characterized in that the exhaust pipe is also placed on the downstream side.