JPH0442071Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a toroidal-shaped coil for detecting welding current, and particularly improves portability, handleability, and tensile strength.

(Prior art) In order to detect large currents for resistance welding, a toroidal coil (so-called toroidal coil) is attached to a resistance welding machine so as to surround a conductor that serves as a current path, such as a secondary conductor, and the coil terminal is A commonly used method is to obtain an output voltage that corresponds to the differential waveform of the welding current.

FIG. 3 shows a typical structure of a toroidal coil. Donut made of magnetic material (toroidal)
A copper wire 102 is wound around the outer periphery of a shaped core 100 and the outside is hardened with an insulator 104 mold.
This structure has both ends 102a and 102b taken out as coil terminals. The coil is installed with its central opening 106 fitting into a secondary conductor (not shown) during assembly of the welding machine.
Therefore, once installed, it becomes an integrated part of the welding machine and cannot be easily removed, which is an inconvenience.

FIG. 4 shows the structure of a conventional removable welding current detection coil devised to solve the drawbacks of the above-mentioned built-in coil. This coil consists of a cloth or rubber belt 200 with a copper wire 202 attached to the outer periphery of the middle part.
Copper wire 202 from one end of the belt.
The winding start part 202a and the winding end part 202b are pulled out and joined to the detection output lines 204, 206 by soldering, and the entire belt 200 and the joined parts 208, 210 are wrapped in an insulator 212. It is called the ``Rogowski Belt'' after his name.

As shown in FIG. 5, when such a band-shaped coil is wound once around the secondary conductor 214 and both ends are brought together and fixed with a string 216 or the like, it forms a toroidal shape, and as shown in FIG. It has a current detection function similar to that of a toroidal coil. Removal of this coil is easy, just by untying the string 216, and there is no need to disassemble the welding machine.

(Problems to be solved by the invention) However, the above-mentioned "Rogowski belt" is quite bulky and is not very convenient to carry. Furthermore, when an external force is applied to the detection output lines 204 and 206 in the direction of arrow F, tensile force is concentrated on the soldered joints 208 and 210 between the detection output lines and the copper wire ends of the coil. As a result, the coils may be frequently attached and detached, or workers may mistakenly connect the detection output wire 2 during installation as shown in Figure 5.
04, 206, the wires may break at the joints 208, 210. If this is to be repaired, the insulator 212 must be peeled off, the joints 208 and 210 inside must be soldered, and then the insulator 212 must be molded over again, which is a cumbersome task.

The present invention was devised in view of these problems, and an object of the present invention is to provide a welding current detection coil that is excellent in portability and handling, and is resistant to disconnection due to tensile force.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a welding current detection coil which has a toroidal shape and detects welding current flowing through a conductor passing through an opening in the center. , a coil conductor is wound for a certain length around the outer periphery of a multicore cord having multiple conductor cores, and the winding start and winding ends are connected to each of the two conductor cores at one end of the cord. Connect one end of the cord, cover the coil conductor winding and joint with an insulator, and connect the other end of the cord with an insulator.
The other end of each conductor core is taken out as a coil terminal.

(Function) The welding current detection coil of the present invention has a rope-like shape with a single multicore cord as its core, so it is not bulky, convenient for portability, and easy to handle.

When using this coil, for example, it is sufficient to wrap the insulator coating (coil) once around the secondary conductor of a welding machine and secure both ends with string, etc., which creates a toroidal shape. , toroidal
Current detection function as a coil can be obtained. In other words, when a welding current flows through the secondary conductor, the magnetic flux generated around it passes through the coil conductor of the coil section, and an induced voltage corresponding to the time differential of the magnetic flux (therefore, the time differential of the welding current) is generated in the coil. Obtained at both ends of the conductor, that is, at the beginning and end of the winding,
The induced voltage is taken out from the other end via the joint and the two conductor cores of the cord.

Even if an external force, especially a tensile force, is applied to the coil of this invention, the sturdy cord will absorb it, and the tensile force will not affect the joint between the coil conductor and the cord conductor core, so it will not come off there. There is no risk of disconnection.

(Example) An example of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a partially cutaway perspective view showing the structure of the current detection coil according to this embodiment.

As shown in the figure, this coil has a single two-core cord 10 as its base, and itself has a rope-like shape. A copper wire (coil conductor) extends over a certain length from one end 10a of the cord 10 to the middle part.
12 is wound around the outer periphery of the cord 10. copper wire 12
The winding start portion 12a and the winding end portion 12b are joined, for example, by soldering, to the respective one ends 14a and 16a of the conductor core exposed on the one end 10a side of the cord 10. The entire copper wire 12 and the joint portions 18 and 20 are covered with an insulator 21, and that portion, that is, the coil portion 22, has a diameter larger than that of the cord 10.

A connector 24 is attached to the other end of the cord 10 for connecting the coil terminal to an input terminal of a welding measuring device or a welding control device. Female pins 26 and 28 of this connector 24 are connected to respective other ends 14b and 16b (not shown) of the conductor core exposed at the other end 10b of the cord 10.

FIG. 2 shows an example of use of the welding current detection coil of this embodiment. 30 is a resistance welding machine body, 32 is a pressure cylinder, 34 is an upper arm, 36 is an upper electrode tip, 38 and 40 are materials to be welded, 42 is a lower electrode tip, and 44 is a lower arm.

As shown in the figure, if the coil part 22 is wound once around the lower arm 44 of the secondary conductor and its both ends are fixed with a string 50, etc., it becomes a toroidal shape, and the current detection function as a toroidal coil is obtained. . That is, when welding current flows through the lower arm 44,
The magnetic flux generated around the arm 44 is transferred to the coil portion 22.
The coil passes through the coil of the copper wire 12, and an induced voltage corresponding to the time derivative of the magnetic flux (therefore, the time derivative of the welding current) is obtained at the winding start portion 12a and the winding end portion 12b of the copper wire 12, The induced voltage is taken out from the terminal pins 26, 28 of the connector 24 via the joints 18, 20 and the conductor core of the cord 10.

Cord 10 may be relatively long, and connector 24 is connected to an input terminal of welding control device 52. The control device 52 integrates the input voltage signal to generate a signal with the same waveform as the welding current, calculates the effective value or average value of the welding current based on this signal,
The measured value is displayed and the welding current value and energization cycle are controlled based on it.

As described above, the welding current detection coil of this embodiment has a rope-like shape with one two-core cord 10 as its core, so it is not bulky, convenient for portability, and easy to handle. Furthermore, even if an external force, especially a tensile force, is applied, the strong cord 10 will receive it, and the tensile force will not affect the joints 18 and 20 between the copper wire 10 of the coil and the cord conductor core. Because of this, it never comes off. Therefore,
Code 10 may occur if the coil is attached to and removed from the welding machine frequently, or if the worker makes a mistake when installing the coil as shown in Figure 2.
Even if you trip over the wire, there is little chance of it breaking.

Note that it is also possible to directly use the other ends 14b and 16b of the conductor core as coil terminals without attaching the connector 24. Further, instead of the two-core cord 10, it is also possible to use other multi-core cords such as a three-core type or a four-core type.

(Effects of the invention) As described above, according to the invention, since the basic body is a rope-like shape with one multi-core cord as the core, it is not bulky, convenient for portability, and easy to handle. In addition, even if a tensile force is applied, the cord absorbs it, and the tensile force does not affect the joint between the coil conductor and the cord conductor core, which has the remarkable effect of reducing the risk of wire breakage. is obtained.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view showing the structure of a welding current detection coil according to an embodiment of the present invention, FIG. 2 is a perspective view showing an example of use (installation) of the coil shown in FIG. 1, and FIG. 4 is a schematic perspective view showing the structure of a conventional typical toroidal coil, FIG. 4 is a schematic perspective view showing the structure of a conventional detachable welding current detection coil, and FIG. It is a perspective view showing an example of use (attachment) of a coil. 10...Two-core cord, 12...Copper wire (coil conductor), 14a, 16a...One end of conductor core, 1
8, 20...Joint part, 21...Insulator, 24...
Connector, 26, 28...female pin.

Claims (1)

[Claims for Utility Model Registration] In a welding current detection coil configured to detect welding current flowing through a conductor having a toroidal shape and passing through an opening in the center, the outer periphery of a multicore cord having a plurality of conductor cores. A coil conductor is wound over a certain length, and the winding start and end of the winding are connected to one end of each of the two conductor cores at one end of the cord, and the winding of the coil conductor is completed. The coil portion and the joint portion are covered with an insulator, and the other end portions of the two conductor cores are taken out as coil terminals at the other end side of the cord. Welding current detection coil.