JPH03210018A - Structure of mounting device for heat shield plate of exhaust pipe - Google Patents

Abstract

PURPOSE:To avoid undercut and prevent torsional deformation by welding a base part of a flange, which has been formed through bending both ends of a heat shield plate in the bending direction so as to separate from an exhaust pipe, to the exhaust pipe abutting to it. CONSTITUTION:A base part 13a of a flange 13, which is formed by bending both ends of a heat shield plate 12 in the bending direction so as to separate from an exhaust pipe 11, is welded to the exhaust pipe 11 abutting to it. Thus, it is possible to avoid concentration of welding heat at a weld zone and to prevent generation of undercut, because welding heat is easily conducted from the weld zone to the rest part of the heat shield plate 12. In addition, the flanges 13 contribute to improvement of the stiffness of the heat shield plate 12. Consequently, even if external force is applied to the heat shield plate 12, noise due to contact of the heat shield plate 12 with the exhaust pipe 11 caused by deformation of the heat shield plate 12 is not generated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a mounting structure for a heat shield plate for an exhaust pipe.

(Conventional technology) The exhaust pipe discharges high-temperature exhaust gas from the engine into the atmosphere, which itself becomes quite high temperature, so it is necessary to eliminate the influence of radiant heat on other parts and prevent radiant heat from being transmitted to plants on the ground when the vehicle is parked. The exhaust pipe requires a heat shield plate in order to prevent the heat from being transmitted.

By the way, when installing this heat shield plate, conventionally, as described in, for example, Japanese Utility Model Application Publication No. 58-162228, the heat shield plate placed below the exhaust pipe was usually bolted to the heat shield plate mounting bracket. Ta. However, the lever mounting structure requires measures to position the heat shield, welds the heat shield mounting bracket to the exhaust pipe, and requires separate parts such as brackets and tightening bolts. As a result, they were unable to avoid cost disadvantages.

Therefore, a technique for directly welding and attaching a heat shield plate to an exhaust pipe was put into practical use, as described in 8 San Jidosha Co., Ltd.'s service bulletin "Stamp" Middle East B-69, published in June 1986. This heat shield mounting structure is shown in Figure 3 (a) and (b).
As clearly shown in (C), the heat shield plate 2 having a substantially semicircular cross section is placed along the exhaust pipe 1 with a gap, so that the middle portion 2a in the exhaust pipe axial direction faces the exhaust pipe 1 at both ends in the curved direction. The distal end edge 2b of the intermediate recessed portion 2a, which is depressed and comes into contact with the exhaust pipe 1, is arc welded to the exhaust pipe 1 as indicated by W.

(Problems to be Solved by the Invention) However, in this heat shield mounting structure, as shown in an enlarged view in FIG. 4, undercuts (P) may occur due to the heat of welding W. This is because a part of the welding heat is transmitted through the heat shield plate 2 and escapes in the middle of the heat shield plate 2 in the curved direction, but most of the heat is concentrated on the tip edge 2b. The undercut (P) becomes a bottleneck in terms of strength, and stress concentration occurs here during vibration, causing cracks and reducing durability.

Therefore, in the above-mentioned conventional technology, it is essential to strictly control the welding conditions so that undercut (P) does not occur during arc welding W. This not only impairs the workability of installing the heat shield plate, but even with this strict control, it is still impossible to completely Undercut P
The reality is that it is not possible to completely eliminate the occurrence of

In addition, the heat shield plate 2 is a press-molded single plate and is easily twisted, making it difficult to maintain the gap between it and the exhaust pipe 1 as designed, so when it receives external force, it interferes with the exhaust pipe and generates abnormal noise. There are some things that need to be done, and countermeasures are also desired.

It is an object of the present invention to solve both of the above-mentioned problems at once by providing a mounting structure for an exhaust pipe heat shield plate that does not cause the above-mentioned undercut and is also less likely to cause the above-mentioned torsional deformation.

(Means for Solving the Problems) For this purpose, the present invention provides a heat shield that is spaced apart from the exhaust pipe in the axial direction of the exhaust pipe, and that the heat shield has a cross section along the exhaust pipe. In a heat shield mounting structure in which the heat shield has a curved shape and welds both ends of the heat shield in the curved direction partially in contact with the exhaust pipe, the both ends of the heat shield in the curved direction are arranged in a direction away from the exhaust pipe. The exhaust pipe is bent to form a flange, and the base of the flange is brought into contact with the exhaust pipe and welded.

(Function) The exhaust pipe guides high-temperature exhaust gas to a predetermined location and releases it to a high temperature. The heat shield blocks radiant heat from the exhaust pipe,
This heat prevents other parts from being damaged and prevents the above heat from reaching plants on the ground.

By the way, when welding the heat shield plate to the exhaust pipe, welded the base of the flange formed by bending both ends of the heat shield plate in the direction away from the exhaust pipe to the exhaust pipe, so welding heat was transferred from the welded part. This makes it possible to prevent welding heat from concentrating on the welded portion by easily transmitting it to the rest of the heat shield plate, thereby preventing the occurrence of undercuts. The above-mentioned flange also contributes to improving the deformation strength of the heat shield plate, and when the heat shield plate is subjected to external force, it will not deform and interfere with the exhaust pipe and generate abnormal noise.

(Example) Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 shows an embodiment of the heat shield plate mounting structure of the present invention,
FIG. 5(a) is an overall perspective view, and FIGS.

Reference numeral 11 indicates an exhaust pipe, and reference numeral 12 indicates a heat shield plate.The heat shield plate I2 is disposed below the exhaust pipe 11 and away from the exhaust pipe. The heat shield plate 12 has a substantially semicircular cross section along the exhaust pipe 11, and is welded to the exhaust pipe 1 at both ends in the curved direction as follows.

That is, both ends of the heat shield plate 12 in the curved direction are bent in a direction away from the exhaust pipe 11 to form the flange 13.

Then, both ends of the heat shield plate 12 in the curved direction on which the flanges 13 are formed are placed in the middle of the exhaust pipe axial direction, and the exhaust pipe 1
1 and in the direction of heat shield curving, heat shield plate 1
A recess 12a is formed in 2. Due to the formation of such a recess, the base 13a of the flange 13 comes into contact with the exhaust pipe 11 at a midpoint in the axial direction of the exhaust pipe, as shown in FIG. As shown, the heat shield plate 12 is attached to the exhaust pipe 11 by arc welding.

According to such a heat shield mounting structure, the heat caused by welding W is easily transmitted from the welded part (flange base 13a) to the rest of the heat shield 12 including the flange 13, and it is possible to prevent welding heat from concentrating on the welded part. As is clear from the enlarged view of FIG. 2, it is possible to avoid undercuts caused by heat concentration in the welded portion.

Therefore, there is no location in the welded portion of the heat shield plate 12 that becomes a bottleneck in terms of strength, and it is possible to eliminate stress concentration locations and improve durability.

On the other hand, the flange 13 also contributes to reinforcing the heat shield plate 12 and improving its deformation strength, and when the heat shield plate receives external force, it deforms greatly and interferes with the exhaust pipe 11, causing abnormal noise. Problems like this can be eliminated.

(Effects of the Invention) Thus, as described above, in the heat shield mounting structure of the present invention, when both ends of the heat shield in the curved direction are welded to the exhaust pipe, flanges are formed at both ends, and the base of the flange is attached to the exhaust pipe. Since it is a welded structure, the flanges can avoid concentration of welding heat and prevent undercuts, and the flanges can also reinforce the heat shield, preventing it from interfering with the exhaust pipe. It is possible to eliminate the problem of generating abnormal noise.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the heat shield plate mounting structure of the present invention,
Figure (a) is an overall perspective view, and (b) and (C) are the first
Cross-sectional view on line I-I and ■-■ in Figure (a), 2nd
The figure is an enlarged sectional view of the welded part of the heat shield plate on the same side, Figure 3 (a) is an overall perspective view showing the conventional heat shield plate mounting structure, Figures (b) and (C) are respectively Figure 3 (a) I-III
and IV-IV sectional view, and FIG. 4 is an enlarged sectional view of the welded portion of the heat shield plate. 11...Exhaust pipe 12...Heat shield plate 12a
...Recess 13...Flange 13a...
・Flange base W...Welding Fig. 3 (a) (b) (C)

Claims (1)

[Claims] 1. A heat shield plate is disposed apart from the exhaust pipe in the axial direction of the exhaust pipe, and the heat shield plate has a curved cross section along the exhaust pipe, and In the heat shield mounting structure in which both curved ends of the plate are partially in contact with the exhaust pipe and welded, both curved ends of the heat shield are bent in a direction away from the exhaust pipe to form a flange; A mounting structure for a heat shield plate for an exhaust pipe, characterized in that the base of the flange is welded in contact with the exhaust pipe.