JPH0239661Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a coil for detecting welding current in a resistance welding machine or the like.

[Prior Art] Conventionally, a toroidal coil as shown in FIG. 7 has been used as a device for detecting welding current in a resistance welding machine. The coil wire 1 of this coil has a completely closed loop shape and is solidified around it with a mold, and a welded secondary conductor (not shown) is passed through the through hole 7 inside the coil wire. When a welding current flows through this secondary conductor, an induced voltage is generated in the coil by the magnetic flux generated around the secondary conductor within the loop of the coil wire 1, and a welding current detection signal is taken out from its output terminal.

[Problems to be solved by the invention] However, the conventional toroidal coil as described above is difficult to attach to a welding machine. That is,
The installation work was troublesome because each part near the secondary conductor had to be separated, the toroidal coil was attached to the secondary conductor, and then each part had to be connected and put back together. Also, depending on the model of the welding machine, such disassembly may not be possible, and in that case, the coil installation location is limited to the vicinity of the welding electrode, or the coil cannot be installed (and therefore cannot be used). Something happened.

The present invention has been made in view of these problems, and an object of the present invention is to provide a welding current detection coil that is extremely easy to attach to a welding machine and has a highly reliable current detection function.

[Means for Solving the Problems] In order to achieve the above object, the welding current detection coil of the present invention has a toroidal shape and detects the welding current flowing through the secondary conductor passing through the through hole inside the coil. The welding current detection coil has an opening for inserting and removing the secondary conductor, and the winding density is relatively high closer to the opening.

Furthermore, in order to enable installation with the opening facing in any direction, a structure is provided in which a lid means is provided for closing the opening with the secondary conductor inserted.

[Function] To install the welding current detection coil of the present invention, all you have to do is attach the coil wire through the opening and insert the secondary conductor into the through hole, and there is no need to remove or disassemble each part on the welding machine side. do not have. To remove the coil, all you have to do is pass through the opening and remove the coil so that the secondary conductor comes out of the through hole, and this operation is also very simple.

Although there is no coil part in this opening, in the present invention, by making the winding density relatively higher closer to the opening, the removal of the coil is compensated for, and the secondary conductor is placed deeper than the opening. It is possible to obtain stable current detection results with substantially constant coil sensitivity both when the coil is located at the same position and when it is located near the opening.

Furthermore, by closing the opening with the lid means with the secondary conductor inserted, it is possible to prevent the coil from separating from the secondary conductor even if the coil is attached in any direction.

[Embodiment] FIG. 1 is a perspective view showing the structure of a main part of a welding current detection coil according to an embodiment of the present invention. The coil body 1 of this welding current detection coil 10 has a toroidal shape, but it is not a closed loop type like the conventional one, but has an opening for inserting and removing a secondary conductor (not shown) in the through hole 7. It has section 4. As shown in FIG. 1a, the coil winding density is made relatively higher closer to the opening 4. As a result, the coil end 1a near the opening 4
is a large diameter portion as shown in FIG. 1a.
According to this winding structure, the amount of coil removed from the opening 4 can be compensated for by the entire coil section, and a current detection function equivalent to that of a closed-loop toroidal coil as shown in FIG. 7 can be obtained. In addition, 3 is the coil body 1
2 is the coil output line.

FIG. 2 is a schematic side view for explaining the operation of this embodiment. Fig. 2a shows a case where a welding conductor 5b with a relatively large cross section is inserted into the through hole 7; Fig. 2b
2C shows the case where the secondary conductor 5b with a relatively small cross section is inserted deep into the through hole 7, and FIG. 2c shows the case where the secondary conductor 5c with a relatively small cross section is inserted near the opening 4. In either case, since the secondary conductor can be taken in and out through the opening 4, there is no need for disassembly or removal on the welding machine side when installing the present coil 10. Also, when comparing the installation shown in Figure 2b and the installation shown in Figure 2c, the former has a larger number of magnetic field line linkages than the latter, and in turn has higher coil sensitivity, and the current detection results of both are different. There appears to be an error. However, as described above with reference to FIG. 1, the winding structure of the present coil 10 has a relatively higher winding density as it approaches the opening 4, and as a result, the number of interlinkages between the magnetic lines of force or the coil The sensitivity is approximately the same, and there is no substantial error in the current detection results.

FIG. 3 is a perspective view showing the appearance of the present coil 10. In this embodiment, a lid 5 is provided for closing the opening 4 with a secondary conductor (not shown) inserted into the through hole 7 of the coil 10. 3a and 5a are holes for receiving fixing means such as bolts. By attaching such a lid 5, the secondary conductor can be connected to the coil 1.
There is no risk of it coming off from the 0 position, and therefore it is possible to install it with the opening 4 facing upward.

FIG. 4 is a perspective view showing the structure of a main part of a welding current detection coil according to another embodiment. The coil 20 of this embodiment is a coil wound around a flexible strip-shaped core 6, and the winding density is increased closer to both ends 6a, 6a. This coil 20
When attaching to a welding machine, both ends 6a, 6a
It is made into a toroidal shape by aligning the two, and the secondary conductor is inserted into the toroidal shape (through hole). This coil 20
The second embodiment is extremely easy to install, is portable, and has the same reliability as the first embodiment in terms of current detection function.

FIG. 5 is a partially sectional perspective view showing an example in which the coil 20 is used in a series spot welding machine. As shown in the figure, the coil 20 may be looped around the welding electrode 21. FIG. 6 shows a modification of the mounting position, in which the coil 20 is hung around the lower workpiece 23 as shown in the figure.
In this case, the amount of reactive current between the welding electrodes 21, 21 can be detected. Similar detection can be performed by applying the coil 20 to the lower welded material 24. 22 is a back bar (metal electrode).

[Effects of the invention] By having the above-described configuration, the present invention has the following effects.

In a welding current detection coil configured to detect a welding current flowing through a secondary conductor having a toroidal shape and passing through a through hole inside the coil, the present invention has an opening for inserting and removing the secondary conductor.
It is possible to easily install a coil without removing or disassembling each part near the secondary conductor, and the structure in which the winding density is relatively high closer to the opening allows the coil to be installed near the opening. By making up for the deletion, it is possible to perform highly reliable current detection with constant coil sensitivity regardless of the placement position of the secondary conductor inside the through hole.

Further, by the structure including the lid means for closing the opening with the secondary conductor inserted, it is possible to prevent the coil from separating from the secondary conductor even if the coil is attached in any direction.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the structure of the main part of a welding current coil according to an embodiment of the present invention, FIG. 2 is a partially sectional side view for explaining the operation of the embodiment, and FIG. FIG. 4 is a perspective view showing the structure of a welding current coil according to another example. FIG. 5 is a partially sectional side view showing an example of how the example coil is attached. FIG. 6 is a partially sectional side view showing another example of mounting the embodiment coil, and FIG. 7 is a perspective view showing the structure of a conventional welding current detection coil. 1... Coil body, 1a... Coil end, 5
a, 5b, 5c...Welding conductor, 6... Winding core, 6a
... Coil end, 4 ... Opening, 7 ... Through hole,
10... Welding current detection coil, 20... Welding current detection coil.

Claims (1)

[Claims for Utility Model Registration] (1) In a welding current detection coil configured to detect a welding current flowing through a secondary conductor having a toroidal shape and passing through a through hole inside the coil, 1. A welding current detection coil having an opening for inserting and removing a secondary conductor, and having a winding density that is relatively high closer to the opening. (2) The welding current detection coil according to claim 1, which is a registered utility model, further comprising a lid means for closing the opening with the secondary conductor inserted therein.