JP2001248437A - Exhaust manifold and manufacturing method for it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust manifold capable of preventing exhaust interference with a small number of part items. SOLUTION: An outer shell member 4 forming one exhaust chamber 18 in communication with each exhaust port P1-P4 is provided, and the exhaust chamber 18 has branch chambers 20-23, which are in communication with the exhaust ports P1-P4 respectively and is formed by partitioning each space between the exhaust ports P1-P4 by throttle parts 21-23, and a gathered pipe chamber 32 where the branch pipe compartments 20-23 gather.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust manifold for collecting exhaust gas from each exhaust port of a multi-cylinder engine and sending the collected exhaust gas to an exhaust pipe, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as disclosed in Japanese Patent Application Laid-Open No. 8-246869, a flange having one large gas inlet communicating with each exhaust port and a large chamber formed in a box shape are formed. There has been proposed one in which a manifold body is integrally formed by pressing a single metal plate.

[0003]

However, in such a conventional apparatus, it is not possible to sufficiently prevent the exhaust gas from interfering with each exhaust port. A partition plate or the like had to be separately provided. For this reason, there is a problem that the number of parts increases and the work process becomes complicated.

An object of the present invention is to provide an exhaust manifold that can prevent exhaust interference with a small number of parts, and a method of manufacturing the same.

[0005]

In order to achieve the above object, the present invention takes the following means to solve the problem. In other words, in an exhaust manifold in which exhaust gas from each exhaust port of a multi-cylinder engine is collected and sent to an exhaust pipe,
An outer shell member forming one exhaust chamber communicating with each of the exhaust ports, wherein the exhaust chamber communicates with each of the exhaust ports, and a branch pipe chamber partitioned between the exhaust ports by a throttle unit; An exhaust manifold, wherein the branch pipe chamber has a collecting pipe chamber in which the branch pipe chambers are gathered.

A punching step of punching an outer shape from a plate material, and a drawing step of drawing according to the shapes of a branch pipe chamber communicating with each of the exhaust ports and a throttle formed between the branch pipe chambers. , A bending step of bending the U-shape, and forming an exhaust chamber by welding the overlapped portion, which is a method for manufacturing an exhaust manifold.

[0007] Further, the connecting pipe portion connected to the exhaust pipe may be bent into a cylindrical shape and the overlapped portion may be welded. Alternatively, the connection pipe portion connected to the exhaust pipe may be formed by burring. Further, the outer shell member may be welded to one large flange formed with each of the introduction holes corresponding to each of the exhaust ports and attached to the engine.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. As shown in FIG. 1, reference numeral 1 denotes an exhaust manifold, which is used for a multi-cylinder (four-cylinder in this embodiment) engine 100. Engine 10
0 includes first to fourth exhaust ports P1 to P4 communicating with the first to fourth cylinders # 1 to # 4.

The exhaust manifold 1 has a large flange 2, an outer shell member 4, and a small flange 6. As shown in FIG. 3, the large flange 2 is provided with four introduction holes 10 to 13 corresponding to the first to fourth exhaust ports P1 to P4. A plurality of mounting holes 14 for mounting with bolts (not shown)
Are formed.

The outer shell member 4 covers all the four introduction holes 10 to 13 and has a substantially U-shaped cross section. The outer shell member 4 and the large flange 2 form an exhaust chamber 18 in which the four introduction holes 10 to 13 communicate with each other. The outer shell member 4 and the large flange 2 are welded to the outer periphery of the outer shell member 4 so that the outer shell member 4 and the large flange 2 are integrated. The exhaust chamber 18 includes first to fourth branch pipe chambers 20 to 23 that are formed corresponding to the introduction holes 10 to 13 and communicate with the first to fourth exhaust ports P1 to P4, respectively.
Between the first to fourth exhaust ports P <b> 1 to P <b> 4, the first to third throttle portions 2 from which the outer shell member 4 protrudes inside the exhaust chamber 18.
4 to 26 are formed, and the first to third throttle portions 24 to 26 are formed.
The first to fourth branch pipe chambers 20 to 23 are partitioned by 26. The adjacent first to fourth branch pipe chambers 20 to 23 communicate with each other through narrow passages 28 to 30. In addition, the first to third
The adjacent first to fourth branch pipe chambers 20 to 23 may be formed so as to be completely shut off and partitioned by the throttle portions 24 to 26.

Each of the first to fourth branch chambers 20 to 23 has a first
To the fourth exhaust ports P1 to P4, have a substantially circular cross-section having a cross-sectional area substantially the same as that of the fourth exhaust ports P1 to P4.
Has a collecting pipe chamber 32 in which the first to fourth branch pipe chambers 20 to 23 are gathered. The collecting pipe chamber 32 is formed in a substantially columnar shape, and is arranged in parallel with the large flange 2.

A connecting pipe portion 34 is formed on the outer shell member 4. The small flange 6 is fitted to the connecting pipe portion 34, and is integrated by welding. It is connected to an exhaust pipe (not shown) on the downstream side via the small flange 6,
Reference numeral 2 is connected to the exhaust pipe via the connection pipe section 34.

Next, a method of manufacturing the exhaust manifold of the present embodiment will be described with reference to FIG. First, as shown in FIG.
The outer shape of the outer shell member 4 is punched from a plate material. Next, FIG.
As shown in (b), in the drawing / forming step, the drawing is performed according to the shapes of the first to fourth branch pipe chambers 20 to 23 and the first to third drawn parts 24 to 26. Also, approximately the upper half of the collecting pipe chamber 32 is drawn and formed in the same manner. Further, the connection pipe section 34
The upper half is drawn.

Subsequently, as shown in FIG. 4C, in the trimming step, trimming is performed along the outer periphery, and the overlapping portion a is bent. The overlapping portion a is U
When they are bent in a letter shape, they are parts that overlap each other. Next, as shown in FIG. 4D and FIG. 4E, in the first and second bending steps, the exhaust chamber 18 is formed by being bent into a U-shape in two steps.

Then, as shown in FIGS.
In the bending step and the forming step, the drawn portions 24 to 26 and the like are formed into a final shape by press working using a cam or the like (not shown). Further, in the connecting pipe portion 34, a cylindrical shape is formed using a core metal, a cam, or the like (not shown), and the overlapping portion b is overlapped.

After the outer shell member 4 is press-formed in this way, the overlapped portion a is welded and the overlapped portion b of the connection pipe portion 34 is also welded, so that the airtightness of the exhaust chamber 18 can be maintained. Along the outer periphery of the outer shell member 4, the outer shell member 4
Is welded to the large flange 2 and the small flange 6 is fitted to the connecting pipe portion 34, and the outer periphery thereof is welded to be integrally formed.

Next, the operation of the above-described exhaust manifold of the present embodiment will be described. With the operation of the engine 100, the exhaust gas is sequentially discharged from the respective exhaust ports P1 to P4 (in this embodiment, in the order of P1, P3, P4, and P2). Exhaust gas exhausted from each of the exhaust ports P1 to P4 flows into the first to fourth branch pipe chambers 20 to 23 through the introduction holes 10 to 13, respectively, and from the first to fourth branch pipe chambers 20 to 23, respectively. It flows into the collecting pipe chamber 32. After the exhaust gas is collected in the collecting pipe chamber 32, the exhaust gas is sent to an exhaust pipe (not shown) via the connection pipe section 34.

Even if exhaust gas is continuously discharged from adjacent exhaust ports P1 to P4, the first to fourth branch pipe chambers 20 to
23, narrow passages 28 to 30 due to throttles 24 to 26
Are formed, it is difficult for the exhaust gas to flow into the adjacent first to fourth branch pipe chambers 20 to 23 due to the resistance of the throttle portions 24 to 26. Therefore, even if the exhaust gas is continuously discharged from the adjacent exhaust ports P1 to P4, it is possible to suppress the occurrence of the interference of the exhaust gas.

According to the above-described exhaust manifold manufacturing method, since the drawn portions 24 to 26 can also be formed by press molding, the exhaust manifold 1 can be manufactured with a small number of components, a simple structure, and low cost. Also, since there are few components, the weight can be reduced.

Next, an exhaust manifold according to a second embodiment different from the above-described embodiment will be described with reference to FIGS. The exhaust manifold 50 according to the second embodiment is used for a three-cylinder engine, and includes a large flange 52 and an outer shell member 54. The outer shell member 54 is formed by press molding as described above. By this press forming, the squeezed portions 56 and 58 are formed, and each branch pipe chamber is partitioned. Further, a connecting pipe portion 60 is formed on the outer shell member 54 by burring, and a storage pipe containing a catalyst (not shown) is fitted to the connecting pipe portion 60.

In the exhaust manifold 50 according to the second embodiment, similarly to the above-described embodiment, the throttle section 56,
Since each branch pipe chamber is partitioned by 58, exhaust interference can be suppressed. In addition, since the drawn portions 56 and 58 can be press-formed, the number of constituent parts is small, and reduction in weight and cost can be achieved.

The present invention is not limited to such an embodiment at all, and can be implemented in various modes without departing from the gist of the present invention.

[0023]

As described in detail above, the exhaust manifold of the present invention does not easily flow into the adjacent branch pipe chamber due to the resistance of the restricting portion, so that even if exhaust gas is continuously discharged from the adjacent exhaust ports. This has the effect of suppressing the occurrence of exhaust gas interference.

According to the exhaust manifold manufacturing method of the present invention, since the drawn portion can be formed by press molding, the number of components is small, the structure is simple, and the manufacturing can be performed at low cost. Also, since there are few components, the weight can be reduced.

[Brief description of the drawings]

FIG. 1 is a front view of an exhaust manifold as one embodiment of the present invention.

FIG. 2 is a central sectional view of an exhaust manifold according to the embodiment.

FIG. 3 is a sectional view taken along the line AA of FIG. 2;

FIG. 4 is an explanatory diagram showing a process order of an exhaust manifold as one embodiment of the present invention.

FIG. 5 is a front view of an exhaust manifold according to a second embodiment.

FIG. 6 is a plan view of an exhaust manifold according to a second embodiment.

[Description of Signs] 1,50 Exhaust manifold 2,52 Large flange 4,54 Outer shell member 6 Small flange 10-13 Introduction hole 14 Mounting hole 18 Exhaust chamber 20 First branch pipe chamber 21 ... Second branch pipe chamber 22... Third branch pipe chamber 23... Fourth branch pipe chamber 24. Chambers 34, 60 Connection pipe section 56 Restriction section 100 Engine

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hirohisa Ohgami 1st Ochaya, Hashime-cho, Okazaki City, Aichi Prefecture Futaba Sangyo Co., Ltd. F-term (reference) 3G004 AA01 BA03 DA02 GA02 GA04 GA06

Claims (5)

[Claims] 1. An exhaust manifold for collecting exhaust gas from each exhaust port of a multi-cylinder engine and sending it to an exhaust pipe, comprising: an outer shell member forming one exhaust chamber communicating with each of the exhaust ports; The exhaust manifold, wherein the chamber has a branch pipe chamber which communicates with each of the exhaust ports and is partitioned between the exhaust ports by a throttle, and a collecting pipe chamber in which the branch pipe chambers are assembled. 2. A punching step of punching an outer shape from a plate material, and a drawing formed by drawing according to the shapes of a branch pipe chamber communicating with each of said exhaust ports and a drawing portion formed between said branch pipe chambers. A method for producing an exhaust manifold, comprising: a step of forming a discharge chamber by welding a lap portion; 3. The exhaust manifold according to claim 2, wherein the connecting pipe portion connected to the exhaust pipe is bent into a cylindrical shape and the overlapped portion is welded. 4. The exhaust manifold according to claim 2, wherein a connecting pipe portion connected to the exhaust pipe is formed by burring. 5. The outer shell member is welded to one large flange formed in each of the introduction ports corresponding to each of the exhaust ports and attached to the engine. Exhaust manifold.