JPS5829588Y2 - Sea heater - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a sheathed heater, and particularly to improvements in the connecting portion between the heating wire and the terminal bar.

Conventionally, as shown in FIGS. 1 and 2, a small-diameter portion 2a of a terminal bar 2 is inserted into a coiled heating wire 1, and then the two are fixed together and inserted into a metal tube 3. It was inserted and the surrounding area was filled with insulating powder 4.

In such a structure, the wire diameter d of the heating wire 1 varies depending on the rating of the sheathed heater, that is, the resistance value.

Therefore, if the coil inner diameter D1 is constant, the coil outer diameter D2 changes depending on the wire diameter d.

In this case, the insulation distances S and S with respect to the metal tube 3 are required to be at least a certain value in terms of insulation properties, so when the wire diameter d becomes thicker, this value becomes smaller, resulting in poor insulation.

For this reason, in the end, the coil outer diameter D2 was kept constant and the coil inner diameter D1 had to be changed in accordance with the wire diameter d.

On the other hand, since the dimensional relationship between the diameter A of the small diameter portion 2a of the terminal bar 2 and the coil inner diameter D1 is A≧D1, a terminal bar 2 with a diameter A suitable for the coil inner diameter D1 according to the wire diameter d is required. Therefore, a type of terminal bar 2 is required depending on the type of wire diameter d,
Not only is production troublesome, but there are many types of inventory, which is difficult to manage, resulting in a large amount of work-in-progress inventory.
There was a problem that it could not be shared.

In order to eliminate this drawback, the present invention makes the tip of the terminal bar tapered and inserts this part into the heating wire coil, making it possible to use one type of terminal bar even if the wire diameters are different. The effects of the present invention will be explained in detail below using examples.

In Fig. 3, 1 is a heating wire wound into a coil, 2 is a terminal bar having an outer diameter larger than the coil inner diameter D1 of this heating wire, and one end is formed to become thinner toward the tip. The portion 2a is inserted into the heating wire 1 and fixed.

3 is a metal tube, and 4 is a heat-resistant insulating powder, such as magnesia powder, filled in this metal tube.

As described above, in the present invention, the tip of the terminal bar 2 is made into a tapered small diameter part 2a, and the coil of the heating wire 1 is inserted and fixed into this part, so that the coil inner diameter D1 of the heating wire 1 is Even if the terminal bar 2 changes, the only difference is the insertion depth t of the tip of the terminal bar 2 into the tapered small diameter part 2a, and if the terminal bar 2 has only one type of tapered part 2a, the wire diameter d It is possible to cope with all changes in the coil inner diameter D1 depending on the type of the coil.

Therefore, since only one type is required, manufacturing is easy, mass production is easy, management is easy, and standardization is possible, which is of great practical value.

[Brief explanation of drawings]

Fig. 1 is a sectional view of the main part of the conventional product, Fig. 2 is an enlarged view of the terminal bar and heating wire, and Fig. 3 is a sectional view of the main part of the present invention. In the figure, 1 is a heating wire, 2 is a terminal bar, 3 is a metal tube, and 4 is an insulating powder. In the drawings, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Scope of utility model registration request] In a device in which one end of a terminal bar is inserted into the end of a coiled heating wire and the heating wire is fixed to the circumferential surface of the heating wire, the heating wire insertion side end of the terminal bar is inserted as the heating wire is inserted toward the tip. A sheathed heater that is formed to gradually become thinner, and a coil portion of a heating wire is inserted only into the thinner portion.