JPH01258891A - Fitting method for radiation fin of cylindrical body - Google Patents

Abstract

PURPOSE:To stabilize welding and to improve the quality of a weld zone by arranging a shield plate at the opposite side to the beam projecting side of a fin in case of the laser beam welding of a radiation fin to a cylindrical body. CONSTITUTION:Welding is executed by a laser beam radiation gun by inserting fixtures 4a, 4b into a cylindrical body 1 and holding a radiation fin 2 on the cylindrical body 1 by a presser bar 5. In this case, the shield plate 6 whose tip part is bent is arranged at the opposite side to the beam radiation side and fixed to the presser bar 5 via an annular seat 8 and a volt 8. In case of the laser beam emitted from a beam radiation gun 3 welding the fin 2, a shielding gas is filled up in the space A formed by the shielding plate, the cylindrical body 1, fin 2 and presser bar 5 by passing through the key hole of a welding point and released in an optimum amt. from a discharging port B. Due to the shielding gas surely sealing a weld zone the laser beam welding is stabilized and the quality of the weld zone is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for attaching heat dissipation fins to a cylindrical body.

[Conventional technology]

Conventionally, methods such as MIG welding, resistance welding, and brazing have been used to attach heat dissipation fins to the cylinder body, but the workability is poor, and the plate thickness of the cylinder body and heat dissipation fins is too large. If the welding material is thin, there is a problem that the heat input during welding will be large and the workpiece will be distorted, so laser beam welding may not be used for this reason. In this case, from the viewpoint of workability and heat dissipation, heat dissipation fins are often welded to the surface of the cylindrical body and to the radiation fins.

[Problem to be solved by the invention]

When laser beam welding a radiation fin to a conventional cylindrical body, the beam shield gas escapes through the keyhole made by the laser beam on the joint surface.

The side of the radiation fin opposite to the laser beam irradiation is also shielded, but the gas flows from the inside including the joint surface to the radiation fin side, and air is likely to be trapped in the part close to the cylinder, causing welding defects such as blowholes. There were problems such as the tendency for this to occur.

This invention was made to solve the above problems, and aims to sufficiently shield the side of the radiation fin opposite to the laser beam irradiation side.

[Means to solve the problem]

The method for attaching the heat dissipation fin according to the present invention is to weld the heat dissipation fin on the side opposite to the laser beam irradiation side immediately before the heat dissipation fin, provide a shield plate with an appropriate distance between the heat dissipation fin, and then laser beam weld the heat dissipation fin. This is what we do.

[Effect]

The method of attaching the radiation fin in this invention is to allow the shielding gas, which passes through the keyhole generated by the laser beam in the radiation fin during laser beam welding, into the space surrounded by the radiation fin and the shield plate, and escapes to the side opposite to the laser beam irradiation. Lock in the time necessary for welding.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In the figure, (1) is a cylindrical body, (2) is a heat dissipation fin that is attached to the cylindrical body (1) by a laser irradiation gun (3) and laser beam welded, (4a), (41) is a cylindrical body that has been previously prepared. A fixture that is inserted into the shaped cylinder (1) and holds the cylinder (1) from the inside, and (5) a presser foot that attaches the radiation fin (2) to the cylinder (1). At the tip of the radiating fin (2), a shield plate (7) is inserted between the radiation fin (2) and a shield plate (6) which is bent at an acute angle, and is fixed with bolts (8) at appropriate intervals. The height of the part (7) is narrower than the distance between the radiation fin (2) and the shield plate (6).
Further, the length of the shield plate (6) in the welding line direction is made longer than the radiation fin (2). (9) is a heat dissipation fin (2)
This is a heat dissipation fin welded to the cylinder (1) immediately before.

Therefore, during welding, the shielding gas flows through the keyhole/L formed at the welding point of the cylinder (1) and the radiation fin (2) attached to the cylinder (1), as shown by the arrow in Figure 2. , passes from the laser beam irradiation side to the opposite side, and the cylinder body (
1), radiation fins (2), presser foot (5), shield plate (
6) and fills the fco space A, and the side of the radiation fin (2) opposite to the laser beam irradiation can be sufficiently shielded with the shielding gas.

Also, on the side opposite to the shielding gas inflow side of space A, there is a wire insert inserted between the presser foot (5) and the shield plate (6).
7), a shield gas discharge port B is provided for shielding gas. Now, as shown by the arrow in FIG. New shielding gas will flow in, and there will be no shortage of shielding.

The shield plate (6) also has an angle T with respect to the radiation fin (2).
This allows you to determine the flow direction of the shielding gas, and unlike the case of a straight shield plate, the shielding gas that has passed through the keyhole hits the shield plate (6) and bounces off, creating a new shield from the keyhole. Nor does it prevent the inflow of gas.

Also, since the shielding gas is also discharged in the direction of the welding line, the shielding gas is more likely to be discharged from the space at the end of the radiation fin (2), but by making the shield plate (6) longer than the radiation fin (2), It can be solved.

In the above explanation, only the flow of shielding scum was described, but the slag generated during welding is also discharged from the space A along with the gas flow shown in the figure, so it is caused by the splashing and adhesion of the sparita. The appearance of the radiation fins (2) does not deteriorate, and work such as removing spatters becomes unnecessary. Furthermore, if there is no shield plate (6), the sparks will be blown onto and adhere to the radiation fins (9) welded just before the radiation fins (1), so there is also the effect that spark removal becomes unnecessary.

〔Effect of the invention〕

As explained above, when a heat dissipation fin is welded to a cylindrical body by laser beam welding, by attaching a shield plate to the presser foot of the heat dissipation fin, the side opposite to the laser beam irradiation side of the heat dissipation fin can also be welded with a welding key. The shielding gas that has passed through the hole provides sufficient shielding, making it possible to perform stable single welding.

[Brief explanation of the drawing]

1st t! ! ! 3. FIG. 2 shows an embodiment of this invention,
FIG. 1 is a sectional view showing a first apparatus for explaining a method of welding a radiation fin to a cylindrical body, and FIG. 2 is a partially enlarged sectional view showing a main part of FIG. 1. In the figure, (1) is a cylindrical body, (2) is a radiation fin, and (3) is a radiating fin.
) is a laser beam irradiation gun, and (6) is a shield plate.

Claims (1)

[Claims] When attaching the radiation fin to the outer periphery of the cylindrical body, when one end of the radiation fin is attached to the cylindrical body and laser beam welded, a shielding plate is provided on the opposite side of the radiation fin to the laser beam irradiation side. How to install heat dissipation fins on cylinder.