JPS5986184A - Heating coil - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a heating coil used in an induction heating device.

Conventional structure and its problems Conventionally, as shown in Figure 1, in order to make it easier to spirally wind a heating coil, it is generally made of stranded wires with an insulating layer provided on a conductor such as copper wire. They gathered together and used the Tsu line. A conventional example of this is shown in Figure 1, where the coil base 1
A litz wire 2 was provided to the coil and fixed with an adhesive 3 such as varnish to form a heating coil.

As shown in the lead portion 4, the strands are twisted into tens to hundreds of strands, so that the collective cross section of the strands after the strands is circular. This circular Noritz wire was spirally wound to obtain a predetermined diameter and inductance. This is because circular wire is easier to wind when winding, and dimensional accuracy can be obtained.

OBJECTS OF THE INVENTION An object of the present invention is to solve the following disadvantages of the conventional wire by using a strand provided with a fusion layer on the outer periphery. The first purpose is to reduce the twist pitch of the strands, save resources by reducing the weight of the heating coil, and reduce loss in the heating coil.

Furthermore, since the wire assembly of the wires is not circular, it is possible to firmly fuse the wires with the adjacent wires. The second objective is not to use adhesive varnish. Since it is fixed mechanically, it is securely fixed to the base and ensures long-term reliability.

In addition, the work environment can be improved without the generation of strange odors, and the curing time of adhesives such as varnishes generally takes a long time, but these problems are also sought to be solved.

Structure of the Invention In order to achieve the above object, the present invention provides a wire assembly in which a conductor is coated with an insulating layer and further has a fusion layer, and the assembled wire is spirally wound with a cross section other than circular. It is.

DESCRIPTION OF THE EMBODIMENTS FIG. 2 shows a sectional view of a wire according to the present invention, and shows a wire 8 having an insulating layer 6 covering the entire circumference of the conductor 5 and further comprising a fusion layer 7.

High-frequency current flows through the conductor 5, but due to the skin effect, the current concentrates only on the surface, so the effective diameter is determined based on the penetration depth determined by the frequency, etc., and the cross-sectional area required for the entire current to flow is determined. Determine the required number of strands and use them as a set of wires.

The insulating layer 6 has a heat resistance temperature that can withstand the operating temperature.

Furthermore, when the fusion layer 7 is brought to a fusion temperature, adjacent portions are fused and the strands or aggregated wires are fixed. To fuse, you can either apply current to the wire and use the wire itself as a heater.
Alternatively, it is possible to increase the temperature of the fusion layer from the outside.

FIG. 3 shows an embodiment using a heating coil.

A heating coil 9 is constructed by sequentially winding a set of tens of wires 8 in a spiral shape starting from the center. The heating coil 9 has a disc-like shape because the parts where the fusion layers are in contact with adjacent lines are fused.

The heating coil 9 is attached to the coil base 1 in the coil holder 1.
Fix with o and caulking 11. The coil holder 10 is located on the circumference of the heating coil 9 and fixes the heating coil 9 from the periphery. Since stress is applied to the lead part 4 during assembly, the coil holder 10 is installed to prevent the fusion part of the lead outlet from coming off.
Provided at the position where the stress should be covered. Although the lead portion 4 does not need to be twisted, it is desirable to provide twisting in order to facilitate assembly and wiring. Twisting is effective when passing through a tube or during work such as soldering the tip. This twisting pitch is an embodiment in which the twisting pitch is made considerably small so that the wires do not fall apart when the lead portion is bent onto the wiring.

In the above case, the heating coil 9 is not twisted at all and only the lead portion 4 is twisted, but if the heating coil 9 is developed in a straight line, the lengths between the individual wires will be uneven, and the wires on which the current will concentrate will be twisted. may occur.

To solve this problem, the heating coil section may also be twisted appropriately. On the other hand, if the twisting pitch is further increased, the assembled wires will have a circular cross section as shown in the conventional example of FIG. 1, and the fusion strength between the assembled wires will be extremely degraded.

The relationship between this fusion force and the coefficient is shown in FIG.

The product K of the diameter of the strands, the number of bundled wires, and the number of twists is equal to the length of 30. If it is set to 50×70 or less, the fusion strength between the bundled wires will not be extremely deteriorated. For example, if 0.5φX20 wires x 2 (pitch number / 3ocnr) = 20, as shown in Figure 4, each strand and the collective wire are fused together at a ratio of approximately 1oO, but it is 90 to 1oO or more. If this is done, the cross section of the set lines becomes circular and the fusion force between the set lines deteriorates. On the other hand, since the lead parts 4 and 1 fall apart, they are twisted at the pitch required for the work as described above. In this case, the fusion force between the set lines can be set independently. When the twist pitch is set and K is approximately 70 or less as in the present invention, there is a degree of freedom due to the gaps between the strands, so forming the assembled wires can be done relatively easily without destroying the insulating layer. FIG. 5A shows another embodiment in which the clustered wires of the strands 8 are formed into an elliptical shape, the adjacent range between the clustered wires is expanded to increase the fusion force, and the heating coil 9 is attached to the coil base 1.
This shows the case where it is fixed to .

FIG. 5B shows still another embodiment, in which a group of wires 8 with the lowest pitch that prevents current concentration is formed into a substantially rectangular shape, and the welding force is applied in the same way as in FIG. 6A. This is a case where the heating coil 9 is fixed to the coil base 1 by increasing the height.

FIGS. 5A and 5B show conditions during forming, which make it possible to set the diameter of the entire heating coil with relatively high precision.

Advantages of the invention 1 Since the heating coil is made of wire bundles wound at the lowest pitch to ensure fusion strength, the length of each strand can be shortened and therefore the weight can be reduced.1 At the same time, it is effective as a resource saving measure.

2. Loss is reduced because the overall length of the heating coil does not need to be known. Therefore, the thermal efficiency of the entire device increases.

3. There is no need to use varnish as the entire heating coil can be fused together with a fusing layer. Therefore, there is no unpleasant odor caused by the varnish.

4. Because it is mechanically fixed to the coil base, only the coil can be replaced. Previously, it was glued together, so the entire coil base had to be replaced.

5. Since the 1-1 constant between the coil base and heating coil is mechanical, there is no thermal deterioration of varnish, etc., and long-term reliability can be ensured. .

6. The twist pitch of the wire assembly between the heating coil and the lead section is different, making it easier to wire the lead section.

7. Since the coil holder fixes the coil at the outer periphery, the heating coil is held over a wide area, so the coil part can be fixed to withstand drops and vibrations using only fusion force.

8. Since the coil holder fixes the exit part of the lead, the holder can withstand external stress and there is no need to rely solely on fusion strength.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a heating coil showing a conventional example, Fig. 2 is a cross-sectional view of a heating coil, Fig. 3 is a cross-sectional view of a heating coil showing an embodiment of the present invention, and Fig. 4 is a fusion force and coefficient. 5A and 5B are sectional views showing other embodiments of the present invention. 1... Coil base, 2... Litz wire,
3... Adhesive, 4... Lead part, 5...
...Conductor, 6...Insulating layer, 7...
Fusion layer, 8...Element wire, 9...Heating coil, 10...Coil holder. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 4

Claims (1)

[Claims] (1) A heating coil used for high-frequency induction heating, which is made by spirally winding an assembled wire having a cross section other than circular, which is a collection of wires having a fusion layer on an insulating layer covered with a conductor. (A heating coil according to the scope of claim 1 of Patent No. 81 (1), which has a holder for fixing a fused spiral heating coil to a coil base, and fixes at least the outer peripheral portion of the heating coil.