JP3697601B2 - Catalyst case - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a catalyst case that is joined by friction welding to an exhaust manifold of an internal combustion engine for automobiles or industrial machines.
[0002]
[Prior art and problems]
Conventionally, as shown in FIG. 5, the exhaust manifold 54 is joined to the joint surface 51a of the catalyst case 51 containing the catalyst 53 by friction welding, and as shown in the bottom view of FIG. 7 and FIG. Further, the outer periphery of the thick part 52 formed in the catalyst case 51 is fixed by a clamp jig 55 and friction welding is performed, and as shown in FIG. From the initial rubbing step, the relative speed and load are increased to the friction step, friction heat is generated on the joint surface 51a, and the joint surface 51a and its vicinity are melted and softened, and then the relative motion is performed in the upset step. At the same time as stopping, a larger load is applied to discharge the melt-softened layer to the outside, and the exhaust manifold 54 is joined to the joint surface 51 a of the catalyst case 51.
[0003]
Conventionally, a large load is applied to the joint surface 51a and softening due to frictional heat causes deformation. Therefore, the thick portion 52 is formed to prevent deformation and damage to the internal catalyst 53. At the time of friction welding, since heat escapes from the clamp jig 55 due to heat transmission and is cooled, there is a means to increase the frictional heat generation or to increase the load applied to the joint surface in order to increase the generation of frictional heat. However, when the relative speed is increased, the vibration increases due to the unbalance of the members to be pressed, and it is necessary to increase the rigidity of the clamp jig 55 and further the rigidity of the pressure welding machine itself.
[0004]
On the other hand, if the load at the time of friction welding is increased, it is necessary to increase the rigidity of the clamp jig 55 and increase the clamping force. Also, the catalyst case 51 is prevented from slipping or deforming with the clamp jig. There is a problem that it is necessary to increase the rigidity and the weight becomes large.
In the friction welding, if the relative motion is stopped in the upsetting process, the heat generation due to the friction stops. At this time, if the heat escape from the clamp jig 55 is large, the molten softened layer is discharged before the molten softened layer is discharged to the outside. Solidifies and the joint surface is incompletely joined. In particular, when the catalyst case 51 is ferritic cast iron, if the heat escape from the clamp jig 55 or the like is large, the joint surface is rapidly cooled, and cementite There was a problem that the joint surface became brittle as a structure.
[0005]
[Means for Solving the Problems]
The present invention has been devised in view of the above-described conventional problems, and aims to provide a catalyst case that can be joined in a good state by friction welding while suppressing deformation. A catalyst case including a catalyst to be joined to a manifold by friction welding, wherein a first thick portion is disposed near a joint surface of the catalyst case near the joint surface, and the first thick portion is disposed near the joint surface of the catalyst case. That is, the second thick part is provided at a position far from the joint surface by interposing the thin part between the thick part and the thick part.
The second gist is that, during friction welding, the entire outer periphery of the second thick portion is fixed and held by a clamp jig, and several peripheral portions of the first thick portion are fixed by a claw-shaped clamp. That is.
[0006]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional configuration diagram of the joined state of the catalyst case and the exhaust manifold. The tip of the exhaust manifold 7 is joined to the joint surface 1a of the catalyst case 1 by friction welding. The catalyst 6 is included, and in this example, as shown in the enlarged cross-sectional view of FIG. 2, the first thick portion 3 is formed in the vicinity of the joint surface 1 a of the catalyst case 1, In the state where the thin portion 4 is interposed from the first thick portion 3, the second thick portion 5 is formed so as to protrude outward at a position far from the joint surface 1 a, and the joint surface A melt burr drop prevention wall 2 is formed on the inner side of 1a so as to protrude upward.
For example, the thickness t1 of the first thick part 3 is 10 to 15 mm, the vertical length L1 of the first thick part 3 is set to about 8 to 10 mm, and the thickness of the second thick part 5 is The thickness t2 is set to 6 mm or more, and the vertical length L3 is set to about 10 to 15 mm. The catalyst case 1 is made of ferritic cast iron.
[0007]
3 and 4, the clamp jig 8 is brought into contact with almost the entire outer periphery of the second thick portion 5 and the catalyst case 1 is firmly fixed and held by the clamp jig 8. At this time, the clamp claw 8a is brought into contact with the outer periphery of the first thick portion 3 at a predetermined interval, and the outer periphery of the first thick portion 3 is fixed at several places by the clamp claw 8a.
[0008]
In this way, the clamp jig 8 is fixed and held, and a load is applied to the joint surface 1a and relative movement is performed as shown in FIG. 6 to generate frictional heat on the joint surface 1a. In this case, since the thin portion 4 is formed between the first thick portion 3 and the second thick portion 5, heat transfer to the second thick portion 5 is performed. As a result, the escape of heat from the clamp jig 8 fixed to the entire outer periphery of the second thick portion 5 can be reduced.
[0009]
Further, the first thick portion 3 is fixed at several places by the clamp claws 8a, and deformation such as opening of the mouth due to the softening of the joint surface 1a can be satisfactorily suppressed. Even if the generation of heat stops, the first thick portion 3 close to the bonding surface 1a serves as a heat mass that prevents a sudden drop in the temperature of the bonding surface 1a, and suppresses rapid cooling of the bonding surface 1a to generate a cementite structure. Can be suppressed satisfactorily.
It should be noted that the melt softening layer discharged to the outside in the upset process is prevented from being discharged to the inside due to the presence of the molten burr dropping prevention wall 2 and can be satisfactorily prevented from scratching the catalyst 6. Become.
[0010]
【The invention's effect】
The present invention is a catalyst case containing a catalyst to be joined to an exhaust manifold by friction welding, and in the vicinity of the joint surface of the catalyst case to be friction welded, the first thick portion is located near the joint surface. Since the second thick part is provided at a position far from the joint surface with a thin part interposed between the first thick part and the first thick part, it is possible to prevent heat from being escaped from the clamping jig during friction welding. As a result, deformation of the catalyst case can be suppressed and a good bonding state can be obtained.
[0011]
Further, at the time of friction welding, the entire outer periphery of the second thick part is fixed and held by a clamp jig, and several outer peripheral parts of the first thick part are fixed by a claw-shaped clamp, so that it is far away at the time of friction welding. The second thick part at the position is securely fixed and held to prevent escape of heat from the clamp jig, and the first thick part is fixed by a claw-shaped clamp so that the catalyst during friction welding is used. The deformation of the case can be satisfactorily suppressed, and the first thick portion can serve as a heat mass, and the generation of cementite structure due to rapid cooling of the joint surface can be satisfactorily suppressed. In the vicinity of, the melt softening layer is discharged well, and it is possible to achieve good bonding.
[Brief description of the drawings]
FIG. 1 is a cross-sectional configuration diagram of a joined state of a catalyst case and an exhaust manifold.
FIG. 2 is an enlarged cross-sectional configuration view in the vicinity of a joint surface of a catalyst case.
FIG. 3 is a front view of a state in which a catalyst case is clamped by a clamping jig.
4 is a bottom view of FIG. 3. FIG.
FIG. 5 is a cross-sectional configuration diagram of a joint state of a conventional catalyst case and an exhaust manifold.
FIG. 6 is a relationship diagram between a load and a relative speed at the time of friction welding.
FIG. 7 is a front configuration diagram of a clamped state by a conventional clamp jig.
8 is a bottom configuration diagram of FIG. 7. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Catalyst case 1a Joint surface 2 Debris drop prevention wall 3 1st thick part 4 Thin part 5 2nd thick part 6 Catalyst 7 Exhaust manifold 8 Clamp jig 8a Clamp claw

Claims (2)

A catalyst case containing a catalyst to be joined to the exhaust manifold by friction welding, wherein a first thick portion and a first thick portion are located in the vicinity of the joint surface of the catalyst case near the joint surface. A catalyst case characterized in that a second thick part is provided at a position far from the joint surface with a thin part interposed between the first thick part and the thick part. 2. At the time of friction welding, the entire outer periphery of the second thick portion is fixed and held by a clamp jig, and several outer peripheral portions of the first thick portion are fixed by a claw-shaped clamp. The catalyst case described in 1.

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