JPH05202745A - Exhaust manifold - Google Patents

Abstract

PURPOSE:To eliminate heat crack and peeling of welding sections and prevent the leakage of exhaust gas by expanding and contracting a bellows in the axial direction and moving cylindrical bodies and both ends of the bellows integratedly in the radial direction with the inside ends of two-piece manifold bodies. CONSTITUTION:An exhaust manifold is connected to a bellows 2 at two-piece manifold bodies 1a and 1b. In this case, the inside ends of the two-piece manifold bodies 1a and 1b are fitted in the bellows 2. The both ends of a cylindrical body 3 are fitted in the inside ends of the two-piece manifold bodies 1a and 1b. In addition, a cylindrical body 4 is locked to the both ends of the bellows 2. Each of the inside ends of the two-piece manifold bodies 1a and 1b, both ends of the bellows 2, and the outside end of the cylindrical body 4 are connected to each other by welding sections 5. By this constitution, the bellows 2 can stretch and contract axially, and both ends of the cylindrical body 4 and the bellows 2 can be radially moved in a body with the inside ends of the two-piece manifold bodies 1a and 1b.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an improvement in the exhaust manifold of an internal combustion engine.

[0002]

2. Description of the Related Art As a conventional exhaust manifold, an actual exhaust manifold is used.
There is one as shown in FIG. 2 of Japanese Patent Publication No. 9-85320, in which the small diameter end portion of the other side manifold body is fitted and inserted into the large diameter end portion of the one side manifold body of the two-division manifold body. A heat-resistant metal bellows is disposed between the end surface of the small diameter end portion and the step portion of the large diameter end portion, and both end edges of the metal bellows are respectively the end surface of the small diameter end portion and the step portion of the large diameter end portion. It is formed in such a manner that it is airtightly pressed against and has a margin between the outer circumference of the metal bellows and the inner circumference of the large diameter end portion.

[0003]

When the pipe wall of the main body of the two-divided manifold is thermally expanded in the axial direction, the metal bellows follow the thermal expansion and are compressed to maintain airtightness, the temperature is lowered, and the two-divided manifold is closed. When the tube wall of the main body contracts in the axial direction, the metal bellows elastically expands and maintains airtightness. In addition, with respect to the thermal expansion and contraction of the two-divided manifold body in the radial direction, both end edges of the metal bellows are arranged in the radial direction between the end surface of the small-diameter end portion and the step portion of the large-diameter end portion of the two-divided manifold body. It keeps airtightness by sliding on. When a conventional exhaust manifold is subjected to repeated high temperature heating and cooling for a long period of time, exhaust gas is emitted from the edge of the metal bellows and the end surface of the small diameter end of the two-divided manifold body and / or the step of the large diameter end. There is a problem of leakage. Therefore, the present invention has been made in order to solve such a problem, and provides an exhaust manifold in which exhaust gas does not leak even when subjected to repeated high temperature heating and cooling for a long period of time.

[0004]

In the exhaust manifold of the present invention, the inner end portion of the two-divided manifold body is fitted into the bellows and both end portions of the cylindrical body are inserted into the inner end portion of the two-divided manifold body. Further, a tubular body is locked at both ends of the bellows.

[0005]

The bellows is capable of expanding and contracting in the axial direction in response to the thermal expansion and contraction of the inner end portion of the two-divided manifold body in the axial direction, and the thermal expansion and contraction of the inner end portion of the two-divided manifold body in the radial direction. On the other hand, both end portions of the tubular body and the bellows are movable in the radial direction integrally with the inner end portion of the two-divided manifold body.

[0006]

1 and 2 show an embodiment of the present invention in which the inner ends of the two-divided manifold bodies 1a and 1b are fitted into the bellows 2 and both ends of the cylindrical body 3 are divided into two. The tubular bodies 4 are inserted into the inner end portions of the main bodies 1a and 1b, and the tubular bodies 4 are provided at both end portions of the bellows 2, and the inner end portions of the two-divided manifold main bodies 1a and 1b, the both end portions of the bellows 2 and the tubular body 4 are provided. The outer ends of the cylindrical body 3 are connected by welded portions 5, and a gap 6 is formed between the one end 3a of the cylindrical body 3 and the inner end of the two-divided manifold body 1b.

The two-divided manifold main bodies 1a and 1b, the bellows 2, the cylindrical body 3, the tubular body 4, the welding portion 5 and the welding wire are formed from Tables 1 and 2, respectively.

[0008]

[Table 1]

[0009]

[Table 2]

When the two-divided manifold bodies 1a and 1b are thermally expanded in the axial direction, the inner end portions of the two-divided manifold bodies 1a and 1b are advanced along the outer peripheral surface of the cylindrical body 3, and
The bellows 2 is compressed and the two-divided manifold body 1a, 1
When b contracts in the axial direction, the two-divided manifold body 1
The inner ends of a and 1b retreat along the outer peripheral surface of the cylindrical body 3, and the bellows 2 expands to absorb the thermal deformation of the two-divided manifold bodies 1a and 1b. Further, when the two-divided manifold main bodies 1a and 1b are thermally expanded and contracted in the radial direction, the inner end portions of the two-divided manifold main bodies 1a and 1b move along both end faces of the cylindrical body 3, and at the same time, the tubular body 4 and the bellows 2 are formed.
Both end portions of the body move in the radial direction integrally with the inner end portions of the two-divided manifold main bodies 1a and 1b. Moreover, the welded portion 5 does not peel off when the inner end portions of the two-divided manifold bodies 1a and 1b are thermally expanded and contracted.

Another embodiment is shown in FIG. 3, in which an annular member 7 is used instead of the tubular body 4, and a two-divided manifold main body 1a,
Even if the 1b, the bellows 2, and the annular member 7 are connected to each other by the welded portion 5, the same operation as in the above-described embodiment is achieved.

[0012]

According to the present invention, the bellows is capable of expanding and contracting in the axial direction, and both ends of the tubular body and the bellows are radially movable integrally with the inner end of the two-divided manifold body. As a result, thermal cracks and peeling of welds do not occur, and exhaust gas does not leak.

[Brief description of drawings]

FIG. 1 is a plan view of an exhaust manifold according to the present invention.

FIG. 2 is a fragmentary plan view showing the inside of the exhaust manifold.

FIG. 3 is a fragmentary plan view showing the interior of an exhaust manifold.

[Explanation of symbols]

 1a 2-division manifold body 1b 2-division manifold body 2 Bellows 3 Cylindrical body 4 Cylindrical body 5 Welded portion 7 Annular member

Claims (3)

[Claims] 1. In an exhaust manifold in which a two-divided manifold body is connected by a bellows, an inner end portion of the two-divided manifold body is fitted into the bellows, and both end portions of a cylindrical body are inside of the two-divided manifold body. An exhaust manifold, characterized in that it is inserted into an end portion, and a tubular body is locked to both end portions of the bellows. 2. The exhaust manifold according to claim 1, wherein an inner end portion of the two-divided manifold body, both end portions of the bellows, and an outer end portion of the tubular body are connected to each other by a welding portion. 3. The exhaust manifold according to claim 1, further comprising an annular member instead of the tubular body.