JPS60131919A - Annealing device for iron core of electric apparatus - Google Patents

Abstract

PURPOSE:To prevent oxidation and discoloration of iron cores and to reduce the time for cooling with a continuous type annealing furnace operating on an induction heating method by dividing an iron core feeder on a heating zone and cooling zone side so that a gaseous atmosphere is thoroughly admitted into the bore side of the iron cores as well. CONSTITUTION:An iron core feeder 5 of a furnace in which a heating zone 3 and a cooling zone 4 are continuously disposed is disposed by a chain conveyor from the heating zone 3 to the cooling zone 4. The feeder 5 is divided at the boundary between the heating zone and the cooling zone 4 or in the zone 4 as in this embodiment and a fresh feeder 5b is disposed from a superposed part 9 to the outlet 7 on the cooling zone side. The moving speed of the conveyors 5a, 5b on the heating and cooling zone sides is made higher with the latter. The iron cores are then placed on the conveyor 5a in tight contact with each other and are fed into the heating zone 3 where the iron cores are heated by an induction heating coil 2 and thereafter the iron cores are fed to the cooling zone 4. The iron cores are transferred onto the conveyor 5b and are spaced from each other so that the gaseous atmosphere is thoroughly admitted to the bore side of the iron cores as well.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention mainly relates to an annealing apparatus by induction heating used for annealing cores of electrical equipment such as small electric motors and small transformers.

Conventional Structures and Problems The iron cores of electrical equipment are often annealed to improve their magnetic properties. This annealing generally uses a heat treatment device that heats by electric resistance heat generation or combustion heat of oil or gas. This heat treatment equipment (hereinafter referred to as a furnace) comes in batch processing and continuous processing types, but since it generally uses an atmospheric heating method, not only the heating time but also the cooling time are long, and energy efficiency is a problem. They are forced to work continuously for 24 hours. We have previously developed an annealing method using induction heating (Japanese Patent Application No. 57-212201) and equipment (for example, Japanese Patent Application No. 58-212201).
No. 16433). Since these methods and devices employ induction heating, the iron core generates heat directly, so compared to furnace annealing using atmosphere heating, it is possible to significantly shorten the time.

Another advantage is that it does not necessarily require continuous work for 24 hours. The first advantage of this induction heating method is the saving of power consumption, which requires about 60% of the power compared to a conventional electric resistance full-heat furnace. When heating is performed with the core lamination direction aligned with the core lamination direction, the heating frequency varies depending on the heating frequency and the amount of power input, but for example, at 1.4 to 1.8 KHz and 6KW power input per 1 KIP of the core. Coil efficiency is about 9
It is 6%.

This is the case when the iron core 1't and the coil 2 are inserted in close contact with each other in the length direction as shown in FIG.

On the other hand, as shown in FIG. 2, when the iron core 1 is inserted into the deformable solenoid coil 2 so that the stacking direction is perpendicular to the feeding direction, the coil efficiency is about 60%. From the above, in order to take advantage of the first advantage of the induction heating method, it is necessary to insert the core into a solenoid coil as shown in FIG. 1 with the core lamination direction aligned with the length direction of the coil. However,
in this case.

Since the cores are in close contact with each other, it is difficult for the atmospheric gas introduced from the cooling zone to flow toward the inner diameter of the core, and since the core is cooled only from the outer circumference, the cooling time is longer. FIG. 3 shows an example of a furnace using the induction heating method. The heating zone 3 and the cooling zone 4 are continuous, and the heating zone 3
A heating coil 2 is arranged outside. On the other hand, the feeding device (conveyor) 6 for the iron core 1 is continuous from the inlet 6 on the heating zone side to the heating zone 3, the entire cooling zone 4 passage, and the cooling zone individual lower. The iron core 1 is placed on this feeding device 6.

It is inserted into the furnace through the inlet 6 and annealed. Also, iron core 1
Because the temperature becomes high during annealing, it is necessary to introduce atmospheric gas to prevent oxidation. This atmospheric gas is, for example, N2
and Dx gas (consisting of C0, CO2H2 and N2) is used, which is introduced from a part 8 of the cooling zone 4 and discharged from the inlet side 6 and the outlet side 7 of the furnace. In the case of this furnace, since the iron cores 1 are in close contact with each other for heating efficiency, the atmospheric gas introduced from the part 8 of the cooling zone 4 is difficult to flow into the inner diameter side of the iron core 1. Cooling of the iron core 1 occurs by heat dissipation from the furnace wall of the cooling zone 4 and contact with atmospheric gas. Therefore, it is necessary for the atmospheric gas to sufficiently flow not only into the outer circumferential side of the iron core 1 but also into the inner circumferential side.

The original purpose of the atmospheric gas is to prevent oxidation of the iron core 1, and if there is insufficient flow into the inner diameter of the heating zone 2, the decomposition gas of the punching oil adhering to the iron core 1 will not be sufficiently discharged. However, due to the residual oxygen brought into the iron core 1, oxidation and discoloration occur, which is a problem.

OBJECTS OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a furnace in which atmospheric gas can sufficiently flow into the inner diameter side of the iron core.

Components of the Invention The present invention is an annealing furnace for electrical equipment iron cores, which has a feature in which the feeding devices for the iron cores on the heating zone side and the cooling zone side are divided and can be moved at different speeds. The purpose of the present invention is to provide a heat treatment equipment that takes full advantage of the advantages of the method and produces iron cores of good quality.

Description of examples Embodiments of the present invention will be described below with reference to the accompanying drawings.

First, the present invention is achieved by devising an iron core feeding device in an iron core annealing furnace using an induction heating method.

This was done based on experimental results showing that it is possible to improve the flow of atmospheric gas. A fourth embodiment of the present invention
As shown in the figure. This figure is a view from above the furnace, and the furnace is
This is a so-called continuous type furnace in which the heating zone 3 and the cooling zone 4 are arranged in series, and the core feeding device 51d is a chain conveyor made of heat-resistant steel, for example, and the heating zone 3 is connected to the cooling zone. 4, and is divided inside the cooling zone, and a new feeding device 5b is disposed from the overlapping portion 9 to the cooling zone individual lower. The iron core is placed on the input chain conveyor 5a at the heating zone side inlet 6, fed into the heating zone 3 at a constant speed, and is heated by the heating coil 2 to raise its temperature. Next, it is fed into the cooling zone 4, where it is taken out and transferred to the chain conveyor 6b. It is cooled and taken out of the furnace through the lower. Incidentally, the splitting position of the chain conveyor may be the boundary 1O between the heating zone 3 and the cooling zone 4.

In this furnace, the chain conveyor is divided into two parts within the furnace, and the moving speed of each part can be easily controlled. In heating zone 3.

From the viewpoint of heating efficiency, it is preferable that the iron cores are in close contact with each other, but on the other hand, in the cooling zone 4, there should be a gap between the iron cores, for example, 10 to 3
It is preferable that it is about 0a. This lever is a chain conveyor 5a divided into two parts.

This problem can be solved by making the moving speed of the cooling zone 6 faster than that of the heating zone f115. Furthermore, when the iron core is transferred between the chain conveyors 6a and 6bK which have different speeds in the furnace, it is expected that the iron core will fall over or be deformed due to conveyor slip due to the difference in speed.

In this case, as shown in FIG. 6, the heating zone side chain conveyor 6a overlaps with the cooling zone side chain conveyor 6b.
If the end portion of the iron core is configured to have a negative inclination with respect to the horizontal direction, the iron core on the heating zone side chain conveyor 5a can be easily transferred to the cooling zone side chain conveyor 5b. That is, since the heating zone side chain conveyor 6.6a moves downward at the conveyor overlap portion 9, it no longer contacts the iron core transferred to the cooling zone side chain conveyor 6.6b. In this case, the angle θ of the negative inclination may be arbitrary, but for example, l
Good purity.

As described in detail, when the furnace of the present invention is adopted, the atmospheric gas introduced into the cooling zone flows throughout the furnace, which not only prevents oxidation and discoloration of the 5-iron core, but also improves cooling efficiency and shortens cooling time. It becomes possible. In our experiments, after heating to yso'c and cooling for 60 minutes, the core temperature was 260°C in the conventional method when the shim and the iron core were in close contact, but in the furnace of the present invention, the core temperature was reduced to 200'C. Looking at this in terms of the size of the equipment, for example, the conventional method has a length of 18 m, but the present invention has a length of 15F11, which is very effective in reducing the size of the equipment.

[Brief explanation of drawings]

Figures 1 and 2 are cross-sectional views showing the structure of the heating section of a core annealing device using the induction heating method, Figure M3 is a cross-sectional view showing the schematic structure of a conventional iron core annealing device using the induction heating method, and Figure 4 is the main Embodiment K of the invention A top view of the feeding device of the annealing apparatus, No. 6
The figure is a basic configuration diagram showing an overlapping portion of a feeding device divided into two parts according to an embodiment of the present invention. 1... Iron core, 2... Induction heating coil,
3... Heating zone, 4... Cooling zone, 6...
...Feeding device, 6a... Heating zone side chain conveyor, 6b... Cooling zone side chain conveyor, 9... Overlapping part. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 12? Upper (・) Saisoya D □ Figure 3

Claims (1)

[Claims] (1) A heating zone and a cooling zone equipped with vll heat conducting heating coils are arranged in succession, and the core feeding device is divided into two at the boundary between the heating zone and the cooling zone or in the cooling zone, and An annealing device for electrical equipment iron cores that can be moved at different speeds with a feeding device. @) The annealing apparatus for an electrical equipment iron core according to claim 1, wherein the speeds of the feeding device on the heating zone side and the feeding device on the cooling zone side can be set individually. (3) Cooling zone 11 at the end of the cooling zone side of the feeding device on the heating zone side
111. The annealing apparatus for an electrical equipment iron core according to claim 1, wherein the feeding device is configured to move along a negative inclination with respect to the horizontal direction at a portion where it overlaps with the feeding device.