JPH03105012A - Flexible tube for exhaust pipe - Google Patents

Abstract

PURPOSE:To prevent thermal deformation and vary the bending rigidity by replacing a portion of a plurality of wires, which form an inner braided tube arranged inside a bellows tube, with a band plate and weaving them into a tubular form. CONSTITUTION:A flexible tube is used to prevent the vibration of an engine from spreading from an exhaust pipe to a vehicle body. An inner braided tube 3 and an outer braided tube 2 are arranged inside and outside a bellows tube 1, respectively. At the same time, both ends of the tubes 1 and 3 are welded to exhaust pipes 4 and 8 via presser rings 5 to 9. In this constitution, a plurality of stainless wires 14, which are placed flat, are regarded as one stripe for forming an inner braided tube 13. In other words, the tube 13 is formed by twilling a plurality of these stripes together with a plurality of band plates 15 into a tubular shape. With this contrivance, thermal deformation can be prevented on account of the band plates 15, while bending rigidity can be varied by changing either the number of stripes or thickness of the band plates 15.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a flexible tube for an automobile exhaust pipe.

[Conventional technology]

In recent years, demands for low vibration and low noise for automobiles have become increasingly sophisticated, and in order to prevent engine vibrations from being transmitted from the exhaust pipe to the body, a flexible tube is incorporated in the middle of the front part of the exhaust pipe. .

As shown in Figure 3, the flexible tube consists of a bellows tube 1 made of a thin stainless steel plate, an outer braider tube 2 covered with stainless steel wire, and an outer braider tube 2 made of stainless steel wire. A three-layer structure consisting of an inner leader tube 3 woven into a tubular shape and inserted inside a bellows tube 1 is used. Both ends of the bellows tube 1 are welded to the exhaust pipes 4, 8 together with both ends of the outer blader tube 2 and the retaining rings 5, 7, and both ends of the inner blader tube 3 are welded to the exhaust pipes 4, 8 together with the retaining rings 6, 9. Welded.

The outer blader tube 2 and the inner blader tube 3 have a twill weave shape as shown in FIGS. 4(a) and 4(b),
A plurality of thin stainless steel wires 1l are arranged flat to form one thread, and a plurality of threads are twilled into a tube shape.

[Problem to be solved by the invention]

When the engine is continuously operated under a high load, extremely high temperature and high velocity exhaust gas flows into the inner blader tube 3 as shown by the arrow 10 in Fig. 3, and some of the exhaust gas flows through the inner blader tube. It passes through and enters the space surrounded by the inner blader tube 3 and the bellows tube 1. It passes through the mesh of the inner blader tube 3 again and flows out into the exhaust pipe 4.

Therefore, the inner blader tube 3 undergoes repeated thermal expansion due to the high temperature of the exhaust gas and passage of the high temperature and high pressure exhaust gas, and after a long period of operation, the inner blader tube 3 is finely disposed close to the outlet side as shown by the broken line 20 in Fig. 3. Transforms into a constricting shape. When the engine is operated continuously at extremely high loads and high speeds, the degree of deformation increases, and when the deformation becomes severe, it creates a large resistance to the flow of exhaust gas, resulting in a reduction in engine performance. In addition, the bending rigidity of a flexible tube is required by the vibration characteristics of the automobile (14) in which it is mounted, and different values are required for each vehicle type, but with conventional technology, the range in which the bending rigidity can be changed is narrow, and the degree of freedom in design is limited. There was also the problem of a lack of.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a flexible tube for an exhaust pipe in which the inner blader tube undergoes less thermal deformation due to exhaust gas and has a greater degree of freedom in designing bending rigidity.

[Means to solve the problem]

In order to achieve the above object, in the flexible tube for an exhaust pipe of the present invention, a plurality of wires, such as stainless steel wires, are arranged flatly as one thread, and a plurality of wires are woven into a tube shape to form an inner braider tube. A bellows tube is provided inside the bellows tube, and is characterized in that some of the plurality of wires constituting the inner preda tube are replaced with strips and knitted into a tube shape. Further, if the same structure as the inner blader tube is used for the outer bellows tube that covers the outside of the bellows tube, it is more effective to change the bending rigidity in design.

[Effect]

The strips woven together with the wires serve to prevent thermal deformation of the inner blader tube.

Furthermore, by changing the number and thickness of the strips, the bending rigidity of the flexible tube can be easily changed in terms of design.

〔Example〕

In the embodiment shown in FIG. 1, the bellows tube 1, the outer blade tube 2, the retaining rings 5, 6, 7, 9, and the exhaust pipes 4, 8 are the same as those in the prior art, and the structure of the inner blade tube l3 is new. It is.

The inner braider l3 has a plurality of stainless steel wires 14 (nine in the embodiment) as shown in FIGS. 2(a) and (b).
The strips arranged flat are considered as one strip, and a plurality of strips and a plurality of strips 15 are twilled and knitted into a tube strip (tubular shape). The thickness of the strip plate 15 is the same as the diameter of the stainless steel wire 14, and the width of the strip plate 15 is the same as the diameter of the stainless steel wire 14.
is set to be nine times the diameter of the stainless steel wire 14 or a value close to it in this embodiment. The band 15 is woven into each strip of a plurality of stainless steel wires 14 arranged flatly at intervals of several strips or at irregular intervals. In FIG. 1, it is shown that every other row, every second row, and every fourth row are knitted.

Further, the material of the band plate 15 is selected from high-grade heat-resistant steel, which does not reduce its bending strength even at high temperatures where the bending strength of the stainless steel wire 14 decreases.

In this example, it was possible to construct a high-strength flexible tube that can withstand much higher temperatures than when the inner braider tube was knitted only with stainless steel wire without causing a significant increase in cost. Furthermore, the bending rigidity was also increased compared to the case of an inner blader tube knitted only from stainless steel wire.

It is clear that the high temperature strength can be increased even if the strip plate 15 is made of the same stainless steel plate as the stainless steel wire l4. The material of the strip l5 can be selected independently of the material of the wire 14.

In addition, if you want to further improve the deformation resistance of the inner blader tube, you can do this by increasing the number of strips or increasing the thickness of the strip while minimizing the impact on flexibility. can be achieved.

Although the embodiment of the invention of claim 2 is not shown in the drawings,
For example, the outer bellows tube 2 that covers the outside of the bellows tube L in FIG.
By adopting the same structure as 3 and selecting the material, number of strips, plate thickness, etc. of the strips in the design, the bending rigidity of the flexible tube can be adapted to the value required by the vehicle for each vehicle model. be able to.

〔Effect of the invention〕

In the present invention, the inner blader tube is constructed by replacing some of the wire strips with strips and knitting them in a twill weave.
A flexible tube with high resistance to thermal deformation can be realized while minimizing the influence on the flexibility of the inner blader tube.

In addition, by adjusting the number of strips and the thickness of the strip, it is possible to easily obtain a bending rigidity suitable for the vehicle type, which increases the degree of freedom in design. It is more effective if the tube is woven with strips.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view of an embodiment of the present invention, and FIGS. 2(a) and (b)
) is an enlarged partial view showing the details of the structure of the inner leader tube 13 in FIG. 1. FIG. 1(a) is a side view, FIG. Figures 3 and 4 (a)
(b) shows the conventional technology, Fig. 3 is a vertical cross-sectional view, and Fig. 4 is (
a) An enlarged partial side view showing details of the structure of the inner blader tube 3 in FIG. 3, and FIG. 4(b) is a view taken along A-A in FIG. 4(a). 13... Inner radar tube, 14... Wire, l5... Strip plate Figure 1 Figure 2 Figure 3 Figure 4 (G) (b)

Claims (1)

[Claims] 1. An inner braider tube is provided inside the bellows tube (1), in which a plurality of wires (14) are arranged in a flat manner, and a plurality of wires (14) are woven into a tube shape in a twill weave. A flexible tube for an automobile exhaust pipe, characterized in that some of the plurality of wires (14) constituting the inner blader tube are replaced with strips (15) and knitted into a tube shape. . 2. Inner blader tube (13) according to claim 1
A flexible tube for an automobile exhaust pipe that uses the same structure as the outer bellows tube that covers the outside of the bellows tube (1).