JPH0672268B2 - Annealing method for iron cores for electrical equipment - Google Patents

Description

The present invention relates to a method for annealing an iron core for electric equipment,
In particular, the present invention relates to a refining method which is a strain removing step in the manufacturing process of iron cores for stationary equipment.

[Prior Art] FIG. 3 is a perspective view showing a conventional iron core for stationary equipment, and FIG. 4 is a schematic explanatory view showing a conventional annealing method for an iron core for stationary equipment made of an amorphous metal.

In the figure, (1) is a stationary device, for example, an annular iron core used in a transformer, and the annular iron core (1) includes a straight portion (1a) and a corner portion (1b).
(2) is a high-frequency excitation winding wound around the linear portion (1a) of the annular core (1) in order to remove the strain of the annular core (1).

In the iron core for electric equipment having the above-mentioned configuration, as shown in Fig. 3, for example, a corner portion (1b) is formed by bending a silicon steel plate or the like, and is wound in multiple layers. An annular core (1) was formed. Therefore, since the corner portion (1b) of the annular core (1) has a mechanical strain including internal strain, it is necessary to remove these strains, and this is performed by annealing in a heating furnace or the like. Was there. This refining temperature is usually 700 to 900 ° C. in the case of a ring-shaped iron core (1) using a silicon steel sheet, and in the case of a ring-shaped iron core (1) using an amorphous metal. The temperature is from 300 ° C to 400 ° C.

Further, in the case of the annular core (1) using an amorphous metal,
As shown in FIG. 4, a method has also been adopted in which high-frequency excitation is performed using a high-frequency excitation winding (2), and the annular core (1) itself is self-heated due to iron loss to perform refining.

In the strain removal refining step in the annealing method of the iron core for electric equipment, it is essential to completely remove the strain,
Therefore, it was important to secure an appropriate refining temperature.

[Problems to be Solved by the Invention] In the method for annealing an iron core for an electric device as described above, large-scale equipment such as a heating furnace for obtaining a high refining temperature for strain relief of the annular iron core (1). However, as a result, the manufacturing cost must be increased. Further, when performing the refining process by high-frequency excitation, it is difficult to control the heat generation temperature of the annular core (1) itself to a constant temperature suitable for refining, and it is affected by various conditions such as ambient temperature. Since it is easy, there is a problem that equipment similar to a heating furnace is eventually required. If you do not have such equipment, it will result in relying on the empirical know-how of workers,
There is also a problem that it is difficult to maintain a certain level of quality due to variations in product quality.

Therefore, the present invention has been made to solve such a problem, and does not require large-scale equipment such as a heating furnace, and can easily secure an appropriate refining temperature for strain relief of the annular core. The purpose is to obtain a method for annealing an iron core for electrical equipment.

[Means for Solving the Problems] A method for annealing an iron core for an electric device according to the present invention is a method for strain relief of an iron core for an electric device, in which the entire annular iron core is maintained at a constant temperature by high-frequency excitation, Irradiation with a laser beam is partially performed on the corners of the iron core and the vicinity thereof to secure the refining temperature necessary for refining and perform strain relief.

[Operation] In the present invention, as strain relief of the iron core for electric equipment,
The entire iron core for electrical equipment is self-heated by high-frequency excitation to maintain a constant temperature, and the corners of this iron core for electrical equipment and the vicinity thereof are partially irradiated with a laser beam to ensure the required refining temperature for refining. Since the strain is removed, it is possible to intensively heat only a necessary portion such as the strained portion, and the temperature can be controlled by controlling the intensity of the laser beam.

[Embodiment] FIG. 1 is a schematic explanatory view showing an annealing method of an iron core for electric equipment according to an embodiment of the present invention, and FIG. 2 is a perspective view showing an iron core for electric equipment according to an embodiment of the present invention. . In the figure, (1) and (2) show the same or corresponding components as those of the conventional example.

In the figure, (3) is a high-frequency power source for supplying high-frequency power to the high-frequency excitation winding (2), (4) is a condenser lens of a laser beam, and (5) is a laser beam condensed by the condenser lens (4). (6) is the point focus of the laser beam.

First, a method of strain removal of the annular core (1) in the manufacturing process of the iron core for electric equipment of this embodiment will be described.

In the figure, the portion that needs to be subjected to strain removal and refining is, of course, the corner portion (1b) of the annular core (1) having a large amount of strain. Therefore, the straight portion (1a) of the annular core (1) in which no strain is generated does not need to be subjected to this refining. However, if such a local refining is performed, there will be a temperature difference due to the refining heat between the corner (1b), which is the refining part, and the straight part (1a), which is the non-purification part. Distortion occurs, which causes deterioration of the characteristics of the annular core (1).

Therefore, in order to prevent thermal strain from occurring due to the temperature difference due to the pure heat of annealing, the entire annular core (1) is raised to a certain temperature, and the temperature difference due to the pure heat of annealing is suppressed to eliminate strain. Need to do. In order to raise the temperature of the entire annular core (1) to a certain constant temperature, in this embodiment, the high frequency excitation winding (2) and the high frequency power supply (3) are used to generate the high frequency excitation winding (2). ) Is supplied with high frequency current,
The annular core (1) is excited at a high frequency, and the temperature of the entire annular core (1) is increased until the temperature difference due to the pure heat of refining does not affect the characteristics of the annular core (1).

Next, the strain removal of the strained portion, which is the actual strain removal step, will be described.

In order to obtain the temperature required for this refining, the corner portion (1b), which is the strained portion of the annular core (1), is irradiated with a laser beam using, for example, a carbon dioxide gas laser, and the point focus (6) is formed. , Raise the corner (1b) to the pure temperature.
If the point focus (6) of this laser beam is moved over the entire corner portion (1b) of the annular core (1) within a short time, the entire corner portion (1b) is required for temporary refining. It is possible to raise the temperature to a proper refining temperature with. Then, after the temperature of the strained portion reaches the annealing temperature, the irradiation of the laser beam is stopped and the annealing is performed by cooling at a constant speed. At this time, the high-frequency exciting current is sequentially weakened in accordance with the cooling rate to prevent a temperature difference between the purified portion and the non-purified portion, and the occurrence of thermal strain can be prevented. The refining process is completed by this series of processes.

According to this refining process, even if the constituent material of the annular core (1) is a silicon steel plate or an amorphous metal,
If the material requires a strain-removal refining, the strain can be removed by the same working process. In particular, when the ring-shaped iron core (1) is made of an amorphous metal, the high-frequency excitation winding (2) used for high-frequency excitation has a direct current for generating a magnetic field when the ring-shaped iron core (1) is cooled. Power can also be supplied.

Further, in this refining process, the boundary between the corner (1b) and the straight part (1a), that is, the boundary between the strained portion and the non-strained portion requires irradiation of a laser beam. If you irradiate the laser beam to the vicinity of the non-distorted part adjacent to the part,
The effect of removing strain can be further improved.

In the above, the refining process for strain relief of the iron core for electric equipment of the embodiment of the present invention has been described. In this embodiment, first, the entire annular core (1) is raised to a certain temperature by high frequency excitation, While maintaining this temperature, the strained part of the annular iron core (1) and its vicinity are partially irradiated with a laser beam to raise the temperature to the temperature required for refining, and then this is cooled and annealed. Therefore, it is possible to intensively heat only a necessary portion such as the strained portion, and the temperature can be controlled by controlling the intensity of the laser beam. Therefore, it is possible to easily secure the refining temperature required for strain relief of the annular core (1) with relatively simple equipment without requiring large-scale equipment such as a heating furnace which has been conventionally required. Therefore, the strain-removing and refining process can be performed at a low cost in a short time, and a highly reliable and stable iron core for electric equipment can be manufactured.

In addition, although the point focus is formed in the strained portion in the irradiation of the laser beam in the above-described embodiment, the present invention can be carried out as follows.

First, the point focus (6) of the laser beam may be a linear focus composed of a plurality of point focal points, or may be a planar focus composed of a plurality of point focal points. Alternatively, the heating may be performed by scanning. In this way, when a linear or planar focus consisting of multiple point focal points is used, the irradiation of the laser beam covers a wider area than in the case of only point focal points, and the temperature control of the refining part is easy. Therefore, there is an effect that the refining work can be done in a short time.

In the above description, the case where the embodiment of the present invention is used for the annular winding core for a transformer is described, but it can also be used for the winding core for stationary equipment such as a reactor, and other than the winding core structure. Even in the case of the iron core for electric equipment, of course, this method can be used for the annular iron core that requires strain relief.

[Effects of the Invention] As described above, according to the method for annealing an iron core for an electric device of the present invention, the entire iron core for an electric device is maintained at a constant temperature by high-frequency excitation for strain relief of the iron core for an electric device. By irradiating the strained part of the iron core and its vicinity with a laser beam to ensure the temperature necessary for the refining and performing the refining, it is possible to intensively heat the distorted part and the like. Since the temperature of the refining temperature can be controlled by controlling the intensity of the laser beam, it is possible to control the refining temperature with relatively simple equipment without the need for large-scale equipment such as a heating furnace that was required in the past. become. Therefore, there is an effect that the strain-removing refining process can be performed at a low cost in a short time, and a highly reliable iron core for electric equipment and the like having stable quality can be manufactured.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing a method of annealing an iron core for electric equipment according to an embodiment of the present invention, FIG. 2 is a perspective view showing an iron core for electric equipment according to an embodiment of the present invention, and FIG. FIG. 4 is a perspective view showing the iron core for electric equipment, and FIG. 4 is a schematic explanatory view showing a conventional annealing method for the iron core for electric equipment made of amorphous metal. In the figure, 1 is an annular core, 1a is a straight line portion, 1b is a corner portion, 2: is a high frequency excitation winding, 3: is a high frequency power supply, and 6: is a point focus. In the drawings, the same reference numerals and symbols indicate the same or corresponding parts.

Claims (4)

[Claims] 1. An iron core for electrical equipment is maintained at a constant temperature by high-frequency excitation, and a laser beam is partially applied to the strained portion of the iron core for electrical equipment and the vicinity thereof so that necessary refining is performed. A method of annealing an iron core for an electric device, characterized by ensuring a temperature and performing a refining process. 2. The annealing of an iron core for electrical equipment according to claim 1, wherein the laser beam is applied to a point focus of the laser light on a strained portion of the iron core for electrical equipment and in the vicinity thereof. Method. 3. The laser beam irradiation according to claim 1, wherein a linear focus composed of a plurality of point focuses of the laser beam is applied to the strained portion of the iron core for electric equipment and its vicinity. Method for Annealing Iron Cores for Electric Equipment. 4. The laser beam irradiation according to claim 1, wherein the laser beam is applied to a strained portion of the iron core for electric equipment and its vicinity with a planar focal point composed of a plurality of point focal points of the laser beam. Method for Annealing Iron Cores for Electric Equipment.