JPH0328125B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a connector welding method for inorganic insulated cables, and in particular to a method for preventing welding defects due to variations in sheath penetration depth.

[Conventional technology]

In general, connector welding for inorganic insulated cables is
As shown in FIG. 6, a metal connector 5 is placed on the metal sheath 2 of the inorganic insulated cable 1, and the end of the connector 5 and the sheath 2 are welded using TIG, plasma, laser, or the like. In the figure, 3 indicates a conductor of the inorganic insulated cable 1, 4 indicates MgO powder filled between the sheath 2 and the conductor 3, and 6 indicates a welding torch.

[Problems to be solved by the invention] Since the metal sheath of an inorganic insulated cable is thin, when welding the sheath and the connector sheathed on the sheath, it is difficult to keep the penetration depth during welding within the sheath thickness even under constant welding conditions. It is difficult to control the workpiece in terms of accuracy and heat accumulation, and it has the disadvantage of causing welding defects. In other words, the air between the MgO powder inside the sheath expands due to the welding heat, and the moisture adsorbed on the surface of the MgO powder evaporates, increasing the pressure inside the sheath, and as a result, the penetration depth of the sheath increases. When the thickness reaches , the molten part is blown away by the internal pressure of the sheath, resulting in defective welding. Furthermore, if the penetration depth of the sheath is small, an unfused portion will be formed in the weld between the sheath and the end of the connector, resulting in poor welding.

[Means for solving problems]

In view of this, as a result of various studies, the present invention has developed a connector welding method for inorganic insulated cables that can prevent the occurrence of welding defects due to variations in the penetration depth of the sheath. In a method in which a metal connector is sheathed on a metal connector and the end of the connector and sheath are welded using a laser,
The laser beam is connected to the cable axis on the 1.0mm high side.
It is characterized by irradiating at an angle of 10 to 60 degrees and making the sheath penetration depth 1/4 to 3/4 of the sheath depth.

That is, in the present invention, as shown in FIG. 1, a metal connector 5 is sheathed on the sheath 2 of an inorganic insulated cable 1, and as shown in FIG. A laser beam 7 with an angle θ of 10 to 60 degrees with respect to the cable 1 axis is irradiated on the side surface high by mm, and the penetration depth D of the sheath 2 is adjusted to 1/4 to 3/4 of the thickness of the sheath 2. Then, the ends of the sheath 2 and connector 5 are welded. The laser used is a device that can produce a narrow weld bead 8 at high speed, that is, a device that can generate a laser beam 7 in the form of a minute spot with high energy density. In the figure, numeral 9 indicates a nozzle that emits a laser beam.

[Effect]

As described above, the present invention irradiates the laser beam at an angle of inclination of 10 to 60 degrees with respect to the cable axis, thereby making it possible to obtain sufficient penetration for welding at a shallow penetration depth, and making it easy to control the penetration depth. Become.

However, the reason for limiting the inclination angle of the laser beam to 10 to 60 degrees is that if the angle is less than 10 degrees, it will not only be difficult to hold the nozzle due to the dimensions, but also the depth of sheath penetration due to cable shaking during welding. Due to the variation, an unfused area is created in the weld, and if the angle exceeds 60 degrees, the penetration depth of the sheath may reach the sheath thickness due to the variation in the penetration depth of the sheath due to cable shaking during welding. This is because the molten part is blown out by the internal pressure of the sheath, which can cause welding defects.

In addition, the laser beam irradiation position was limited to the side surface of the connector end, which is 0.1 to 1.0 mm higher than the sheath surface, due to cable shaking during welding, etc. At a height of less than 0.1 mm, the penetration depth of the sheath is less than the sheath thickness. This is because if the height exceeds 1.0 mm, an unfused part will be formed in the weld, and both will cause welding defects.

Also, the penetration depth of the sheath should be set to 1/4 of the sheath thickness.
The reason why we limited it to ~3/4 is because the penetration depth varies due to cable shaking during welding, etc. If it is less than 1/4, an unfused part will occur in the welded part, and if it exceeds 3/4, the penetration depth of the sheath will become smaller than that of the sheath. This is because some parts reach a thickness of

〔Example〕

Thickness of inorganic insulated cable as shown in Figure 1
A connector with an end wall thickness of 0.75 mm was mounted on a 0.4 mm metal sheath, and the beam inclination angle θ, the height h of the irradiation position from the sheath surface, and the sheath penetration depth D were varied as shown in Figure 2. The sheath and connector end were welded together using a laser. The laser has a capacity
Typical results using a 1KW carbon dioxide laser device are shown in Figures 3 to 5.

Figure 3 A, B, and C are average output 500W and welding speed
This shows the results of welding at 1.8 m/min, when the irradiation position of beam 7 (height h from the sheath surface) was constant (0.3 mm) and the inclination angle θ of beam 7 was varied. For A, θ is 70 degrees, and B is θ.
C shows the case where θ is 7 degrees, and as is clear from B, when the inclination angle θ is 30 degrees, the melted bead 8 becomes about 1/2 of the thickness of the sheath 2, and in detail, the angle θ is 30 degrees. It can be seen that good results are obtained between 10 and 60 degrees. On the other hand, as shown in A, when the inclination angle θ is 70 degrees, more specifically, at an angle exceeding 60 degrees, the weld bead 8 reaches the thickness of the sheath 2, and as shown in C, the inclination angle θ is 7 degrees, more specifically, at an angle exceeding 60 degrees. It can be seen that when the welding angle is less than 10 degrees, the depth of the weld bead 8 is shallow and an unfused portion is formed in the weld.

In addition, Fig. 4 A, B, and C show a welding speed of 1.8 m/min.
This shows the results of varying the output up to 1KW, with the inclination angle θ of beam 7 constant (30 degrees).
This shows the case where the irradiation position of beam 7 (height h from the sheath surface) is changed;
C shows the case where h is 1.2 mm, and as is clear from B, when h is 0.5 mm, the melted bead 8 becomes about 1/2 of the thickness of the sheath 2, and in detail, h is 0.1. It can be seen that good results can be obtained within the range of ~1.0 mm. On the other hand, as shown in A, h is 0
mm, more specifically, when h is less than 0.1 mm, the welding area is small and the welding strength is low, as shown in C, when h is 1.2 mm,
For details, if h exceeds 1.0mm, weld bead 8
It can be seen that the depth of the weld is shallow, resulting in an unmelted part in the weld.

Furthermore, Fig. 5 A, B, and C show the results when welding was performed at a welding speed of 1.8 m/min, and the inclination angle θ of the beam 7 was
By varying the irradiation position of the beam 7 (height h from the sheath surface) within a range of 0.1 to 1.0 mm, and further changing the output of the laser beam, the bead 8 melts. Shows the case where the depth is changed, A: θ is 10 degrees, h is 0.1 mm, penetration bead depth D is 0.07 mm, B: θ is 30 degrees, h is 0.5
mm, D is 0.2mm, θ is 60 degrees, h is 0.5mm, D is
The case where D is 0.35 mm is shown, and as is clear from B, D is 0.2 mm, specifically D is 1/4 to 1/4 of the thickness of sheath 2.
It can be seen that good welding can be obtained in 3/4.
On the other hand, as shown in A, θ is 10 degrees, h is 0.2 mm,
D is 0.07mm, specifically D is 1/4 of the thickness of sheath 2
If it is less than 1/4 of the thickness of sheath 2, an unfused part will be formed in the welded part, and if θ is 60 degrees, h is 0.3 mm, and D is 0.35 mm, as shown in C, if D exceeds 1/4 of the thickness of sheath 2, a weld bead 8 reaches the thickness of sheath 2,
It can be seen that blow-out occurs due to the internal pressure of the sheath 2.

〔Effect of the invention〕

In this way, according to the present invention, in connector welding of inorganic insulated cables, the laser beam is inclined at 10 to 60 degrees with respect to the cable axis, and the welding angle is 0.1 to 60 degrees from the sheath surface.
By irradiating the side surface of the connector end 1.0mm higher and controlling the sheath penetration depth to 1/4 to 3/4 of the sheath thickness, variations in sheath penetration depth due to cable shaking during welding, etc. It is possible to prevent welding defects due to this, and has a significant industrial effect.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing an example of the welding method of the present invention, Figure 2 is an explanatory diagram showing an enlarged main part of Figure 1, and Figure 3 is an explanatory diagram showing an example of the welding method of the present invention.
Figures A, B, and C show the influence of the tilt angle of beam irradiation.
degree, C is an explanatory diagram showing the case where the inclination angle is 7 degrees, 4th
Figures A, B, and C show the influence of the beam irradiation position, where A is 0 mm from the sheath surface and b is from the sheath surface.
0.5mm, C is an explanatory diagram showing the case of 1.2mm from the sheath surface, Figure 5 A, B, and C show the influence of sheath penetration depth, A is penetration depth of 0.07mm, and B is penetration depth. 0.2 mm, C is an explanatory diagram showing a case where the penetration depth is 0.35 mm, and FIG. 6 is an explanatory diagram showing an example of a conventional welding method. 1...Inorganic insulated cable, 2...Sheath, 3...Conductor, 4...MgO powder, 5...Connector, 6...Torch, 7...Laser beam, 8...Penetration bead, 9...
laser nozzle.

Claims (1)

[Claims] 1 In a method in which a metal connector is sheathed on the metal sheath of an inorganic insulated cable and the end of the connector is welded to the sheath using a laser, a laser beam is applied to the side surface of the connector end that is 0.1 to 1.0 mm higher than the sheath surface and aligned with the cable axis. Irradiate at an angle of 10 to 60 degrees to reduce the penetration depth of the sheath to 1/4 of the sheath thickness.
A connector welding method for inorganic insulated cables characterized by ~3/4.