JP2018032703A - Transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transformer reduced in iron loss.SOLUTION: A transformer includes: a rectangular annular wound core comprising a laminate of electromagnetic steel sheets, and having two legs and two yokes, at least one yoke having a junction; a winding wire wound about at least one of the legs; a pressing member pressing a yoke having the junction in a lamination direction of the electromagnetic steel sheets; and a tension applying member applying tension in a circumferential direction to at least a part of the wound core.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a transformer.

In transformers (transformers), low iron loss has been one of the most important issues from the viewpoint of high efficiency, and low iron loss has been studied from various viewpoints.
As one technique for reducing iron loss, it is known to generate tension in the circumferential direction of an annular iron core.

  In Patent Document 1, an insulating plate is disposed above and below an iron core window frame in a wound iron core wound in a spiral shape with an amorphous magnetic thin plate so as to pass through the iron core window portion. A wound core type transformer configured to connect the lower insulating plates with a connecting material and tighten the gap between the insulating plates so that a tensile force is applied to the core leg portion of the wound core. It is disclosed.

  Japanese Patent Laid-Open No. 2004-26883 discloses two inner molds made of a heat-resistant material, a center bar extending between the inner molds, and a coil spring surrounding the center bar inside an amorphous magnetic ribbon wound in a coil shape. In addition, a nut that is screwed along the center rod and presses the coil spring is set, and by compressing and repelling the coil spring by the screwing of the nut, a force in a direction away from each other is applied to the two inner molds. A method for manufacturing a wound core is disclosed in which an expansion force is applied to a magnetic ribbon and annealing is performed in this state.

  Further, in Patent Document 3, the tip portions of a plurality of silicon steel strips wound around a drum are fixed to a winding mold, and the tip portions of a plurality of amorphous sheets wound around another drum are attached to the silicon steel strip. In this state, the winding die is rotated while applying tension to the silicon steel strip, and the amorphous sheet is sandwiched between the silicon steel strips and wound together with the silicon steel strip on the winding die. A rotating iron core manufacturing method is disclosed.

  On the other hand, Patent Document 4 discloses a high magnetic flux density grain-oriented electrical steel sheet that is provided with a specific tension by an insulating coating agent and has excellent magnetic properties and iron core workability. According to Patent Document 4, it is said that a directional electrical steel sheet with low iron loss can be obtained by applying a high-tensile film to the steel sheet.

Japanese Patent Laid-Open No. 60-18909 JP-A-4-3111010 JP 58-57895 A JP-A-6-145998

When manufacturing a wound iron core using an amorphous magnetic thin film, as disclosed in Patent Documents 1 to 3, etc., the amorphous magnetic thin film is usually wound while applying tension to form a wound core. Therefore, the wound core of the amorphous magnetic thin film does not have a joint.
On the other hand, when manufacturing a wound iron core using an electromagnetic steel sheet, a joint for inserting a winding in the wound iron core may be provided. The winding portion can be easily wound around the wound core core by opening the joint portion once, inserting it into the winding from the opened end of the wound core core, and rejoining the joint portion.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a transformer with reduced iron loss.

The transformer according to the present invention is composed of a laminate of electromagnetic steel sheets, and a rectangular annular wound iron core having a joint,
A winding wound around at least one of the columnar portions of the wound core;
A pressurizing member that pressurizes the columnar portion having the joint in the laminating direction of the electromagnetic steel sheet;
And a tension applying member that applies a circumferential tension to at least one columnar portion of the wound core.

  In the transformer of the present invention, it is preferable that the electrical steel sheet does not have a tension coating from the viewpoint of reducing iron loss and reducing the manufacturing cost of the electrical steel sheet.

  Moreover, in the transformer of the present invention, the electrical steel sheet has a surface oxide layer from the viewpoint that insulation between the laminated electrical steel sheets is secured, overcurrent is suppressed, and iron loss can be further reduced. preferable.

  According to the present invention, a transformer with reduced iron loss can be provided.

It is a mimetic diagram showing one embodiment of a transformer concerning the present invention. It is a perspective view which shows an example of the yoke part containing the junction part 3 in embodiment of FIG. It is a perspective view which shows an example of the yoke part seen from the angle different from FIG. It is a schematic diagram for demonstrating the open state 3 (A) of the junction part 3, and the junction state 3 (B). It is a schematic diagram which shows another one Embodiment of the trans | transformer which concerns on this invention.

Hereinafter, the transformer according to the present invention will be described in detail.
As used in this specification, the shape and geometric conditions and their degree are specified. For example, terms such as “parallel”, “vertical”, “same”, length and angle values, etc. are strictly Without being bound by meaning, it should be interpreted including the extent to which similar functions can be expected.

The transformer according to the present invention is composed of a laminate of electromagnetic steel sheets, and a rectangular annular wound iron core having a joint,
A winding wound around at least one of the columnar portions of the wound core;
A pressurizing member that pressurizes the columnar portion having the joint in the laminating direction of the electromagnetic steel sheet;
And a tension applying member that applies a circumferential tension to at least one columnar portion of the wound core.

2. Description of the Related Art Conventionally, a wound iron core using an electromagnetic steel sheet has been known in which a joint for inserting a winding is provided. In many cases, the magnetic steel sheet used for such a wound iron core is provided with a tension coating in order to ensure tension in the circumferential direction. However, sufficient tension in the circumferential direction was not obtained with the tension coating.
Therefore, the present inventors have studied to provide a tension applying member for applying a circumferential tension to the wound core. However, when circumferential tension is applied to the wound iron core having the joint, there arises a problem that the joint is not able to withstand the tension and is peeled off. Therefore, by pressing the yoke part having the joint part in the laminating direction of the electromagnetic steel sheets, it was possible to solve the peeling of the joint part and obtain a transformer with reduced iron loss.
According to the present invention, circumferential tension can be applied to the wound core without using a tension coating. Therefore, you may use the electromagnetic steel plate which does not have a tension | tensile_strength film, and can suppress the manufacturing cost of an electromagnetic steel plate. Furthermore, by performing surface insulation treatment by a simple method such as oxidizing the surface of the electrical steel sheet to form a surface oxide layer, vortices generated in the direction of lamination of the electrical steel sheets can be further suppressed while suppressing the manufacturing cost of the electrical steel sheet. Since current can also be suppressed, a transformer in which iron loss is further suppressed can be obtained.

The transformer of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram showing an embodiment of a transformer according to the present invention. 2 and 3 are perspective views showing an example of the joint portion 3 in the embodiment of FIG. FIG. 4 is a schematic diagram for explaining the released state 3 (A) and the joined state (B) of the joined portion 3. FIG. 5 is a schematic view showing another embodiment of the transformer according to the present invention.
The transformer shown in the example of FIG. 1 includes a rectangular annular wound core 1 having four columnar portions, two opposing columnar portions around which a winding 2a or 2b is wound, and a joint portion 3. And a columnar part. Although the winding 2a and the winding 2b are wound around the wound core 1, for convenience of explanation, FIG. 1 is a cross-sectional view in the vicinity of the columnar portion. The columnar part around which the winding is wound and the columnar part having the joint 3 may be the same columnar part. However, from the viewpoint of the ease of rejoining the joint 3 and the performance of the transformer, the joint It is preferable that the winding is wound around the columnar portion adjacent to the columnar portion having 3. The joining method of the joint is not particularly limited, and any conventionally known method may be used. From the viewpoint of the mechanical strength of the joint, buttrap joining or step lap joining is preferable. It is preferable that the step lap joint shown in FIG.

In this invention, the pressurizing member which pressurizes the columnar part which has the junction part 3 in the lamination direction of an electromagnetic steel plate is provided. In the example of FIG. 1, pressurizing plates 4, 4a, pressurizing bolts 5 and pressurizing nuts 6 are used as the pressurizing members. In the example of FIG. 1, pressurizing plates 4 and 4 a are arranged on both sides in the stacking direction (X-axis direction) of the columnar part having the joint 3, and are tightened uniformly by the pressurizing bolt 5 and the pressurizing nut 6. And pressurizing in the laminating direction of the electromagnetic steel sheet. The shape of the pressing plate is not particularly limited as long as it is a shape that can be uniformly pressed in the laminating direction of the electromagnetic steel plates. For example, it may be a flat plate, but from the point that it can be strongly and uniformly tightened, FIG. It is preferable to use a pressure plate having a rectangular shape along the outer periphery of the columnar portion as shown in FIG. In the present invention, it is only necessary to pressurize at least the columnar portions having the joint portions. From the point that the iron loss is improved by pressurization, each of the four columnar portions of the rectangular annular wound core 1 is pressurized. It is preferable that the member is disposed and pressurized.
The pressure applied in the laminating direction of the electrical steel sheet is not particularly limited, but is preferably 0.1 MPa or more from the viewpoint of suppressing peeling of the joint, and is further 0.3 MPa or more from the point of reducing iron loss. It is more preferable that the pressure is 0.4 MPa or more. On the other hand, it is preferable that it is 30 Mpa or less from the point of size reduction of the jig which applies a compressive force.

Moreover, in this invention, the tension | tensile_strength provision member which provides the tension | tensile_strength of the circumferential direction to the at least 1 columnar part of a wound iron core is provided. Iron loss is reduced by applying circumferential tension to the columnar portion. In the example of FIG. 1, a tension applying plate 4a, a tension applying stud bolt 7, and a tension applying nut 8 are used as the tension applying member. As shown in the example of FIG. 1, the tension applying plate 4a may be used integrally with the pressurizing plate, or the tension applying plate and the pressurizing plate may be different. In the example of FIG. 1, tension in the X-axis direction is applied to two opposing columnar portions around which the winding 2a and the winding 2b are wound. In the example of FIG. 5, tension in the Z-axis direction is applied to two opposing columnar portions that do not have windings.
The tension applied to the columnar part of the wound core is not particularly limited, but is preferably 0.1 Pa or more, more preferably 0.2 Pa or more, and 0.5 MPa or more from the viewpoint of reducing iron loss. Even more preferred. On the other hand, it is preferably 10 MPa or less from the viewpoint of downsizing the jig for applying tension.

  In the present invention, the electrical steel sheet may be appropriately selected and used from conventionally known electrical steel sheets, for example, an electrical steel sheet made of silicon steel containing 0.1 to 4.5% by mass of silicon. It is done. In the present invention, the electrical steel sheet may be a non-oriented electrical steel sheet or a directional electrical steel sheet, but it is preferable to use a directional electrical steel sheet that is preferably used in a general transformer. Since the present invention can suppress changes in magnetostriction, noise can be reduced even when a grain-oriented electrical steel sheet having a relatively large magnetostriction is used. Moreover, although the thickness of an electromagnetic steel plate is not specifically limited, For example, the electromagnetic steel plate of 0.1 mm or more and 1 mm or less is normally used suitably, Especially, the electromagnetic steel plate of 0.15 mm or more and 0.8 mm or less is preferable.

In the present invention, the surface of the electrical steel sheet is preferably insulated. Since the surface is insulated, eddy currents generated in the lamination direction of the electromagnetic steel sheets can be suppressed. The insulation treatment method for the surface of the electrical steel sheet can be appropriately selected from conventionally known methods. For example, a known tension coating may be formed on the surface of the electrical steel sheet, or it may have a surface oxide layer formed by oxidizing the surface of the electrical steel sheet. Examples of the tension coating include a coating film of a treatment solution containing colloidal silica and phosphate, and the treatment solution may further contain an organic resin. On the other hand, from the viewpoint of magnetic properties and the like, the magnetic steel sheet preferably has a thin film, and more preferably has no film. From such a viewpoint, it is preferable that the electrical steel sheet used for the transformer of the present invention does not have a tension coating.
The electrical steel sheet used for the transformer of the present invention preferably has a surface oxide layer from the viewpoint of suppressing overcurrent generated in the stacking direction and being excellent in magnetic properties.

In the transformer of the present invention, the size of the wound iron core 1 is not particularly limited, and can be set to a desired size according to the application. For example, the length of the iron core (the total length in the X-axis direction in FIG. 1) can be 50 mm or more and 1000 mm or less, and preferably 100 mm or more and 500 mm or less. The width of the iron core (the total length in the Z-axis direction in FIG. 1) can be 50 mm or more and 1000 mm or less, and preferably 100 mm or more and 500 mm or less. The width (length in the Y-axis direction in FIG. 1) of the electrical steel sheet constituting the iron core can be 10 mm or more and 400 mm or less, and preferably 20 mm or more and 300 mm or less. Moreover, the lamination thickness of the laminated body which comprises an iron core can be 10 mm or more and 200 mm or less, and it is preferable to set it as 20 mm or more and 150 mm or less.
For example, in the case of a 20 kVA transformer, a preferred embodiment includes a wound core having a central window portion of 140 mm × 70 mm, a laminated thickness of 60 mm, and a plate width of 150 mm.
Moreover, as another structure of a wound iron core, it can be set as the well-known structure generally used as a wound iron core for transformers.

  In the present invention, the winding is used by being connected to a circuit, and usually has a primary coil connected to a circuit including a power source and a secondary coil connected to an extraction circuit. Although it does not specifically limit as a material of a coil | winding, Copper, aluminum, etc. are mentioned. The configuration of the winding can be a known configuration generally used for transformers. Moreover, as another structure of a transformer, it can be set as the well-known structure generally used for a transformer.

The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.
Hereinafter, the present invention will be specifically described with reference to examples. These descriptions do not limit the present invention.

(Production of transformer 1)
Using a grain-oriented electrical steel sheet, a wound iron core having a joint was produced. This grain-oriented electrical steel sheet has a tension coating composed mainly of phosphate and colloidal silica on its surface. Subsequently, the said junction part was once open | released, the edge part of the open wound core was inserted in the coil | winding, and the said junction part was rejoined. The two leg portions of the wound core and the two yoke portions are each provided with a pressure member that pressurizes in the laminating direction of the electromagnetic steel sheets, and a tension applying member that applies circumferential tension to the legs of the wound core. And the transformer 1 shown in the example of FIG.

(Production of transformer 2)
In the production of the transformer 1, in the same manner as the production of the transformer 1 except that a directional electrical steel sheet having a surface oxide layer and having no tension film was used instead of the directional electrical steel sheet having a tension film, the transformer 1 2 was produced.

(Evaluation of iron loss)
The pressure in the stacking direction and the tension in the circumferential direction of the produced transformer were adjusted to the combinations shown in Table 1, and the iron loss was evaluated. The iron loss reduction rate in Table 1 is No. It is a value calculated by the following formula with the iron loss value of 1 as a reference.
Iron loss reduction rate (%) = (P ₁ −P) / P ₁ × 100
(In the formula, P ₁ represents an iron loss value in No. ₁ in Table 1, and P represents an iron loss value under each condition in Table 1.)

[Summary of results]
As shown in Table 1, it has been clarified that the iron loss is reduced by applying tension in the circumferential direction of the wound iron core and applying pressure in the laminating direction of the electromagnetic steel sheets constituting the wound iron core. No. 1-No. From the comparison of 7, it became clear that the iron loss is further reduced by increasing the circumferential tension. No. 9-No. From the comparison of 12, it became clear that the iron loss was further reduced by increasing the compressive force in the stacking direction. No. 5 and No. From the comparison with No. 13, etc., in the wound iron core of the present invention having a tension applying member that applies tension in the circumferential direction, a transformer with reduced iron loss can be manufactured by using an electromagnetic steel sheet having a surface oxide layer. Became clear.

DESCRIPTION OF SYMBOLS 1 Winding iron core 2a, 2b Winding 3 Junction part 4 Pressurizing plate 4a Pressurizing plate and tensioning plate 5 Pressurizing bolt 6 Pressurizing nut 7 Tensioning stud bolt 8 Tensioning nut

Claims (3)

A rectangular annular wound iron core made of a laminate of electromagnetic steel sheets and having a joint,
A winding wound around at least one of the columnar portions of the wound core;
A pressurizing member that pressurizes the columnar portion having the joint in the laminating direction of the electromagnetic steel sheet;
A transformer comprising: a tension applying member that applies circumferential tension to at least one columnar portion of the wound core.   The transformer according to claim 1, wherein the electromagnetic steel sheet does not have a tension coating.   The transformer according to claim 1, wherein the electromagnetic steel sheet has a surface oxide layer.