JPS596752B2 - Joining method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a joining method using electromagnetic solid phase joining method.

In the electromagnetic solid-phase bonding method, for example, as shown in Japanese Patent Publication No. 47-39825, a bonding member is inserted into a high-frequency induction coil, and a high-frequency heating current is first passed through the coil.
After heating by the induced current, a forming current consisting of large current pulses is passed through the coil, and the resulting electromagnetic attractive force between the joining members is used to join the joining members.

In the electromagnetic solid phase joining method shown in this publication, a pair of tubular members are butt welded, but this method can also be applied to lap welding, in which parts of the members are overlapped and welded. . By the way, when a pair of tubular members are overlapped and welded using this electromagnetic solid phase joining method, the pair of tubular members are usually fitted so that some parts overlap, fixed immovably, and heated. It is necessary to polish the joint surfaces before fitting the parts together, and if heating is not performed in a non-oxidizing atmosphere, there are problems such as the joint surfaces being oxidized and the desired joint not being achieved. Futsuta. Furthermore, when a single-turn high-frequency induction coil 1 is used as shown in FIG. 1, leakage magnetic flux occurs in the gap 3 formed in the annular portion 2 of the coil 1, causing There was a drawback that the heating of the parts was different from that of other parts, and uneven heating occurred, making it impossible to obtain the required bond. In the present invention, a plurality of tubular members are arranged coaxially so that some of them overlap, and the weight portions are moved so as to rub against each other to heat them by friction, and at the same time, the weight portions are heated evenly by high frequency heating. This makes it possible to easily perform the required joints.

Hereinafter, the present invention will be described by way of examples with reference to the drawings.
FIG. 2 is a schematic configuration diagram of the device for explaining the present invention. On the side of the device main body 10, there are a pair of upper and lower fixing plates 1.
1 and 12 are installed in a protruding manner, and furthermore, a single-turn high frequency induction coil 13 is attached to the intermediate portion thereof so as to be movable up and down.

On the lower fixing plate 12, a lower chuck 15 is connected to a clutch mechanism 14 attached to the lower surface of the fixing plate 12.
a10 is provided and faces the upper chuck 15b attached to the lower surface side of the upper fixing plate 11. The pair of upper and lower chucks 15a, 15b and the high frequency induction coil 13
The annular portion of is coaxial, and the upper chuck 15b is attached to be movable toward the lower chuck 15a, so that a tubular member of arbitrary size can be held coaxially with the annular portion of the high-frequency induction coil 13 using the upper and lower chucks 15a and 15b. It is now possible to hold it. The clutch mechanism 14 has a rotating mechanism that is connected to a motor 15 fixed to the lower fixed plate 12 by a V-belt 16 and rotates, and the rotation of the lower chuck 15a can be made on and off by a control mechanism (not shown). In the illustrated example, a pair of chucks 15a, 15b
The case is shown in which a pair of tubular members A and B to be joined to each other are chucked, and the tubular member A held by the upper chuck 15b has one end formed with a large diameter, and a hole inside the large diameter end. Tubular member B held by lower chuck 15a
The joint ends of the members A and B are inserted, and the weight portions 18 of both members A and B are inserted.
The state in which the high-frequency induction coil 13 is set is shown in FIG.

According to this device, the tubular member A is held by the upper chuck 15b and cannot rotate, but the tubular member B is held by the lower chuck 15a and can rotate.

Therefore, to join both members A and B, firstly, both members A and B are held as described above, and then the tubular member B held by the lower chuck 15a is rotated, and at the same time, a high frequency wave is applied to the high frequency induction coil 13. A heating current is applied to heat the weight portions 18 of both members A and B.

When the weight portions 18 of both members A and B reach a certain temperature, the control mechanism is operated to stop the rotation of the lower chuck 15a, and a large current pulse larger than the high frequency heating current is applied to the high frequency induction coil 13. Both members A and B can be joined by applying a forming current of: To describe this joining using a specific example of a copper pipe and an aluminum pipe, the outer diameter is 87nm.
7! The copper tube is formed into a fitting shape with an outer diameter of 6 mm with respect to an aluminum tube with an Lφ wall thickness of 1 mm.The aluminum tube is held in the upper chuck 15b and the copper tube is held in the lower chuck 15a, and the copper tube is Rotates at a speed of 10 revolutions/second.

The rotation time is preferably about 5 to 10 seconds. The current flowing through the high-frequency induction coil 13 during rotation is such that the aluminum tube on the outside of the weight section becomes almost red-hot or slightly red-hot. According to this joining method, the weight portions 18 of the joining members A and B can be heated uniformly, and the required joining can be performed.

In other words, when it comes to joining the above-mentioned copper pipe and aluminum pipe, it is difficult to uniformly join the entire surface of the weight part using conventional electromagnetic solid-phase joining that does not use friction, and the tensile strength is 10k9f on average. With the method of the above example, it is possible to achieve an average of 15 kgf, and in a leak test, 75 out of 100
Although this leakage occurred, the method of the above embodiment was able to reduce the occurrence to zero. That is, according to the above-described joining method, when the pair of tubular members A and B are heated, the joint surfaces of the pair of tubular members A and B are rubbed together by the rotation of the tubular member B held by the lower chuck 15a, so that the weight portion 18 is not bent. In addition, the joint surfaces are heated uniformly, and the oxide film is removed from the joint surfaces by friction, so the synergistic effect of these actions results in the required uniform and strong joint. I was able to get it.

Next, other embodiments of the present invention will be described. In the above embodiment, one of the tubular members is rotated so that the weight portions rub against each other, but for example, the tubular member A held by the upper chuck 15b is rotated while the tubular member B is held by the lower chuck 15a. The two members may be rotated in opposite directions so that both members rub against each other. Alternatively, both members may be rotated in the same direction and rubbed against each other with a difference in the number of rotations.

In particular, the method of rotating these two members can heat the weight part more evenly than in the previous embodiment, and can obtain a good bond. Furthermore, instead of rotating the tubular member, the same effect can be achieved by vibrating at least one of the members so that the weights rub against each other.

As described above, the present invention arranges a plurality of tubular members such that at least some of them overlap, and heats the tubular members with a high-frequency induction coil while moving at least one of the tubular members so as to rub the weighted portions against each other. A forming current consisting of large current pulses is applied to the high-frequency induction coil to join the plurality of tubular members at the weight portion, so that the weight portion is uniformly heated over the entire surface by synergistic heating of friction and high-frequency heating. Also,
Since the oxide film is removed from the joint surfaces by friction, it is possible to easily obtain the required uniform and strong joint.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a single-turn high-frequency induction coil, and FIG. 2 is an embodiment diagram for explaining the present invention.

Claims (1)

[Claims] 1 A method of coaxially arranging a plurality of tubular members so that at least some of them overlap, and a method of moving at least one of the tubular members to heat the weight portions of the plurality of tubular members by friction, and at the same time heating the weight portions with high frequency. A joining method comprising: heating with an induction coil; and applying a forming current to the high-frequency induction coil to join the weight portions heated by the friction and high-frequency heating.