JP2002054435A - Exhaust manifold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exhaust manifold to generate a perfect frictional pressure bonding by the use of a low-cost clamp jig. SOLUTION: The exhaust manifold 1 is structured so that a cylinder head mounting flange 2 is installed at one-side ends of a plurality of branch pipes 3 and a flange part 5 is formed in the downstream of a converging part 4 at the other end and is joined with a catalyst case 6 by frictional pressure bonding, wherein a rib 11 is formed protrusively along the converging part 4 of the flange part 5 for preventing a warp of the clamp jig 9 to clamp the area near the converging part 4 when the frictional pressure bonding is to be made.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust manifold.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG.
The exhaust manifold 1 and the catalyst case 6 are clamped by clamp jigs 9 and 10, respectively, and they are joined by friction welding. In the exhaust manifold 1, a plurality of branch pipes 3 are formed in a curved shape from a cylinder head mounting flange 2 at one end, and the plurality of branch pipes 3 are gathered at a gathering part 4 at the other end, and a downstream side of the gathering part 4 A flange portion 5 is formed on the catalyst case 6, and the flange portion 5 is friction-welded to the flange portion 7 on the catalyst case 6 side by a friction-welding surface 8. This is performed by applying a load to the exhaust manifold 1 while rotating the case 6 side.

The exhaust manifold 1 is provided with a cylinder head mounting flange 2 at the end of a plurality of curved branch pipes 3.
Is formed, the clamp jig 9 for clamping the exhaust manifold 1 has a cantilever structure, and receives a pressure from the catalyst case 6 side during the friction welding so that the front end of the clamp jig 9 is fitted. At 9a, as shown by the imaginary line in FIG. 6, warpage occurs in the direction of reducing the surface pressure,
Due to the warpage, the surface pressure of the friction welding surface 8 becomes non-uniform, and when a large load is applied to the friction welding surface 8 in the final upset process, the discharge of the molten portion becomes insufficient, and the friction welding surface 8 There has been a problem that the joining state is incomplete.

To solve such a problem, FIG.
As shown in the figure, the tip fitting portion 9a of the clamp jig 9
For example, a proposal has been made to form a clamp fitting portion 9b that meshes in a crank shape to prevent the clamp jig 9 from warping during friction welding. However, in order to secure the strength of the clamp fitting portion 9b, a high accuracy is required. However, there are drawbacks such as an increase in cost, and a shorter life of the clamp jig 9 than before.

[0005]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned conventional problems, and has as its object to provide an exhaust manifold capable of preventing warpage of a clamp jig and performing good friction welding. The gist of the invention is that a plurality of branch pipes have a cylinder head mounting flange formed at one end and a flange formed at a downstream side of a collecting part at the other end, and the flange is joined to the catalyst case by friction welding. In the exhaust manifold, a rib is formed so as to protrude from the flange portion along the collecting portion in order to prevent a clamp jig for clamping the vicinity of the collecting portion during friction welding.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a front configuration diagram in a friction welding state, and FIG. 2 is a side configuration diagram of FIG. In the figure, an exhaust manifold 1 has a cylinder head mounting flange 2 formed on the upstream end side of a plurality of branch pipes 3, 3, 3 and a collecting part 4 formed on a downstream end of the branch pipe 3, 3 on the opposite side. A flange 5 is integrally formed so as to protrude outward on the downstream side of the gathering portion 4, and in this example, the rib 1 extends from the flange 5 toward the upstream side along the gathering portion 4.
The ribs 11, 11 are integrally formed so as to protrude, and the ribs 11, 11 are arranged between the front end fitting portions 9a, 9a of the clamp jig 9 for sandwiching the outer periphery of the collecting portion 4 during friction welding. Have been. The outer peripheral surface of the catalyst case 6 is clamped by the clamp jig 10.

The ribs 11 protruding from the exhaust manifold 1 may be formed as a pair, or may be formed at only one location as shown in FIG. In the configuration of the exhaust manifold 1 shown in FIG. 3, a mounting portion 12 is formed so as to protrude on a side opposite to the rib 11, and an EGR or O ₂ sensor is mounted on the mounting portion 12. FIG. 4 is a left side view of FIG. 3, and FIG. 5 is a right side view of FIG.

As described above, the collecting portion 4 of the exhaust manifold 1
If ribs 11 are formed on the outside of the
When the catalyst case 6 is rotated and pressure is applied in a state where the outside of the collecting portion 4 is clamped by the clamp jig 9, the tip aligning portion 9 a of the clamp jig 9 comes into contact with the rib 11 and the tip aligning portion 9 a Warpage can be satisfactorily prevented, and the tip mating portion 9a does not warp as in the prior art. Therefore, the surface pressure in the friction welding portion 8 becomes uniform, and the molten portion can be sufficiently formed in the subsequent upset process. Is discharged to the outside to obtain a complete joint state. As described above, if the ribs 11 are formed on the exhaust manifold 1, it is not necessary to form the clamp fitting portion 9b in the clamp jig 9, and the clamp jig 9 does not require much accuracy and is inexpensive. It can be formed.

[0009]

According to the present invention, a cylinder head mounting flange is formed at one end of a plurality of branch pipes, and a flange is formed at a downstream side of a collecting part at the other end, and the flange is formed by friction welding. In the exhaust manifold that is joined to the catalyst case, the ribs protrude from the flange along the assembly to prevent warping of the clamp jig that clamps the vicinity of the assembly during friction welding. Pressure is applied to the exhaust manifold side from
When pressure is applied to the clamp jig holding the exhaust manifold, the ribs can prevent the warp of the clamp jig satisfactorily, and the clamp jig does not warp. Becomes uniform, and a perfect bonding state can be obtained. In addition, since the clamp jig does not require much precision, it can be formed at low cost, and the life of the clamp jig can be extended.

[Brief description of the drawings]

FIG. 1 is a front configuration diagram showing a clamp state during friction welding.

FIG. 2 is a side view showing the configuration of FIG.

FIG. 3 is a front view showing an example in which a rib is formed on a side opposite to a mounting portion of the exhaust manifold.

FIG. 4 is a left side view of FIG. 3;

FIG. 5 is a right side view of FIG. 3;

FIG. 6 is an explanatory diagram showing that a clamp jig is warped during conventional friction welding.

FIG. 7 is a clamp state diagram when a fitting portion is formed in a clamp jig.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Exhaust manifold 2 Cylinder head mounting flange 3 Branch pipe 4 Assembly part 5 Flange part 6 Catalyst case 8 Friction contact surface 9 Clamp jig 9a Tip fitting part 10 Clamp jig 11 Rib 12 Mounting part

Claims (1)

[Claims] 1. A cylinder head mounting flange is formed on one end of a plurality of branch pipes, and a flange is formed on a downstream side of a collecting part on the other end, and the flange is joined to a catalyst case by friction welding. In the exhaust manifold, a rib is formed so as to protrude from the flange portion along the assembly portion in order to prevent a clamp jig for clamping the vicinity of the assembly portion during friction welding.