JP6819136B2 - Trance - Google Patents

Description

The present invention relates to a transformer.

In transformers, low iron loss has been one of the important issues from the viewpoint of high efficiency, and low iron loss has been studied from various viewpoints.
It is known that tension is generated in the circumferential direction of the annular iron core as one method for reducing iron loss.

In Patent Document 1, an insulating plate is arranged above and below the iron core window frame in a wound iron core spirally wound with an amorphous magnetic thin plate so as to face the iron core window portion and penetrate the iron core window portion. A wound iron core type transformer that connects the lower insulating plates with a connecting material and tightens the insulating plates so that the distance between the insulating plates is large so that a tensile force is applied to the iron core leg portion of the wound iron core. It is disclosed.

In Patent Document 2, two inner molds made of a heat-resistant material, a central rod extending between the inner molds, and a coil spring surrounding the central rod are described in a coiled amorphous magnetic thin band. , And a nut that is screwed along the center rod to press the coil spring is set, and the compression repulsion of the coil spring due to the screwing of this nut applies a force in the direction away from each other to the two inner molds and is amorphous. A method for manufacturing a wound iron core in which an expanding force is applied to a magnetic thin band and annealed in this state is disclosed.

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 fixed 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 around the winding die together with the silicon steel strips. A method of manufacturing a wound iron core to be turned is disclosed.

On the other hand, Patent Document 4 discloses a high magnetic flux density directional electromagnetic steel sheet having excellent magnetic properties and iron core workability, to which a specific tension is applied by an insulating coating agent. According to Patent Document 4, by applying a high-strength coating to a steel sheet, a grain-oriented electrical steel sheet with low iron loss can be obtained.

Japanese Unexamined Patent Publication No. 60-18909 Japanese Unexamined Patent Publication No. 4-311010 Japanese Unexamined Patent Publication No. 58-57895 Japanese Unexamined Patent Publication No. 6-145998

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

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

The transformer according to the present invention is made of a laminated body of electrical steel sheets, and has a rectangular annular wound iron core having a joint and a wound iron core.
A winding wound around at least one of the columnar portions of the wound iron core,
A pressure member that is arranged in each of all the columnar portions of the wound steel core and pressurizes the columnar portions in the laminating direction of the electromagnetic steel sheet, and
A tension applying member that applies tension in the circumferential direction to at least one columnar portion of the wound iron core is provided.
Each of the pressurizing members is arranged on both sides of the columnar portion in the stacking direction, and has a rectangular shape along the outer circumference of the columnar portion, and a pressurizing plate for tightening the pressurizing plate from both sides in the stacking direction of the columnar portion. Equipped with bolts and pressurizing nuts
Of the pressurizing plates arranged in the window portion of the columnar portion, at least a pair of pressurizing plates arranged at facing positions in the window portion are selected as the pressurizing and tensioning plates.
The tension applying member includes at least a pair of the pressurizing and tension applying plates arranged at facing positions in the window portion of the columnar portion, and a tension applying stud bolt connecting the pair of pressurizing and tension applying plates. Further, it is characterized by including a pair of tension applying nuts arranged at both ends of the tension applying stud bolt.
In the transformer of the present invention, the pressing force of the pressurizing member is preferably 0.1 MPa or more.

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

Further, in the transformer of the present invention, since the electromagnetic steel sheet has a surface oxide layer, the insulation between the laminated electromagnetic steel sheets is ensured, overcurrent is suppressed, and iron loss can be further reduced. preferable.

According to the present invention, it is possible to provide a transformer with reduced iron loss.

It is a schematic diagram which shows one Embodiment of the transformer which concerns on this invention. It is a perspective view which shows an example of the yoke part including the joint part 3 in the 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 joint part 3 and the joint state 3 (B). It is a schematic diagram which shows another embodiment of the transformer which concerns on this invention.

Hereinafter, the transformer according to the present invention will be described in detail.
It should be noted that the terms such as "parallel", "vertical", and "same" and the values of length and angle used in the present specification to specify the shape and geometric conditions and their degrees are strict. Without being bound by meaning, we will interpret it including the range in which similar functions can be expected.

The transformer according to the present invention is made of a laminated body of electrical steel sheets, and has a rectangular annular wound iron core having a joint and a wound iron core.
A winding wound around at least one of the columnar portions of the wound iron core,
A pressure member that pressurizes the columnar portion having the joint portion in the stacking direction of the electromagnetic steel sheet, and
It is characterized in that at least one columnar portion of the wound iron core is provided with a tension applying member that applies tension in the circumferential direction.

Conventionally, it has been known that a wound iron core using an electromagnetic steel plate is provided with a joint for inserting a winding. The electromagnetic steel sheet used for such a wound steel core is often provided with a tension coating in order to secure tension in the circumferential direction. However, with the tension coating, sufficient tension in the circumferential direction could not be obtained.
Therefore, the present inventors have studied to provide a tension applying member for applying a tension in the circumferential direction to the wound iron core. However, when tension is applied in the circumferential direction to the wound iron core having the joint portion, there is a problem that the joint portion cannot withstand the tension and peels off. Therefore, by applying pressure to the yoke portion having the joint portion in the laminating direction of the electromagnetic steel sheets, it was possible to solve the peeling of the joint portion and obtain a transformer with reduced iron loss.
According to the present invention, tension in the circumferential direction can be applied to the wound iron core without using a tension coating. Therefore, an electromagnetic steel sheet having no tension coating may be used, and the manufacturing cost of the electromagnetic steel sheet can be suppressed. 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, eddies generated in the stacking direction of the electrical steel sheet while suppressing the manufacturing cost of the electrical steel sheet. Since the current can also be suppressed, a transformer with more suppressed iron loss can be obtained.

The transformer of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view 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. 1, respectively. Further, FIG. 4 is a schematic view for explaining the open state 3 (A) and the joint state (B) of the joint portion 3. Further, 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 iron core 1 having four columnar portions, and has two opposed columnar portions around which windings 2a or windings 2b are wound and a joint portion 3. It has a columnar part. The winding 2a and the winding 2b are wound around the wound iron core 1, but for convenience of explanation, FIG. 1 shows a cross-sectional view near the columnar portion. The columnar portion around which the winding is wound and the columnar portion having the joint portion 3 may be the same columnar portion, but from the viewpoint of ease of rejoining the joint portion 3 and the performance of the transformer, the joint portion 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 portion is not particularly limited, and any conventionally known method may be used, but from the viewpoint of the mechanical strength of the joint portion, butt wrap joint or step wrap joint is preferable, and among them, FIG. It is preferable to use the step wrap joint shown in.

In the present invention, the columnar portion having the joint portion 3 is provided with a pressurizing member that pressurizes in the stacking direction of the electromagnetic steel sheets. In the example of FIG. 1, pressurizing plates 4, 4a, pressurizing bolts 5, and pressurizing nuts 6 are used as pressurizing members. In the example of FIG. 1, the pressurizing plates 4 and 4a are arranged on both sides of the columnar portion having the joint portion 3 in the stacking direction (in the X-axis direction), and are uniformly tightened by the pressurizing bolt 5 and the pressurizing nut 6. , Pressurize in the laminating direction of the electromagnetic steel sheet. The shape of the pressurizing plate is not particularly limited as long as it can be uniformly pressurized in the laminating direction of the electromagnetic steel sheets. For example, it may be a flat plate, but from the viewpoint of strong and uniform tightening, FIG. It is preferable to use a pressure plate having a rectangular shape along the outer circumference of the columnar portion as shown in FIG. In the present invention, it is sufficient to pressurize at least the columnar portion having the joint portion, but from the viewpoint that the iron loss is improved by the pressurization, the columnar portion having the rectangular annular wound iron core 1 is pressurized. It is preferable that the members are arranged and pressurized.
The pressure applied in the laminating direction of the electromagnetic steel sheet is not particularly limited, but is preferably 0.1 MPa or more from the viewpoint of suppressing peeling of the joint portion, and 0.3 MPa or more from the viewpoint of further reducing iron loss. More preferably, it is more preferably 0.4 MPa or more. On the other hand, from the viewpoint of downsizing of the jig to which the compressive force is applied, it is preferably 30 MPa or less.

Further, in the present invention, a tension applying member that applies tension in the circumferential direction to at least one columnar portion of the wound iron core is provided. Iron loss is reduced by applying tension in the circumferential direction to the columnar portion. In the example of FIG. 1, as the tension applying member, the tension applying plate 4a, the tension applying stud bolt 7, and the tension applying nut 8 are used. As shown in the example of FIG. 1, the tension applying plate 4a may be used integrally with the pressurizing plate, and the tension applying plate and the pressurizing plate may be different from each other. 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. Further, in the example of FIG. 5, tension in the Z-axis direction is applied to two opposing columnar portions having no winding.
The tension applied to the columnar portion of the wound iron 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. Is even more preferable. On the other hand, from the viewpoint of miniaturization of the jig to which tension is applied, it is preferably 10 MPa or less.

In the present invention, the electromagnetic steel sheet may be appropriately selected from conventionally known electromagnetic steel sheets and used, and examples thereof include an electromagnetic steel sheet made of silicon steel containing 0.1% by mass or more and 4.5% by mass or less of silicon. Be done. In the present invention, the electrical steel sheet may be a non-oriented electrical steel sheet or a grain-oriented electrical steel sheet, but it is preferable to use a grain-oriented electrical steel sheet that is preferably used in a general transformer. Since the present invention can suppress the change in magnetostriction, it is possible to reduce noise even by using a grain-oriented electrical steel sheet having a relatively large magnetostriction. The thickness of the electromagnetic steel sheet is not particularly limited, but for example, an electromagnetic steel sheet of 0.1 mm or more and 1 mm or less is preferably used, and among them, an electromagnetic steel sheet of 0.15 mm or more and 0.8 mm or less is preferable.

Further, in the present invention, it is preferable that the surface of the electromagnetic steel sheet is insulated. Since the surface is insulated, eddy currents generated in the stacking direction of the electromagnetic steel sheets can be suppressed. As the method for insulating the surface of the electromagnetic steel sheet, a conventionally known method can be appropriately selected. For example, a known tension film may be formed on the surface of the electromagnetic steel sheet, or a surface oxide layer formed by oxidizing the surface of the electromagnetic steel sheet may be provided. Examples of the tension coating include a coating film of a treatment solution containing colloidal silica and a phosphate, and the treatment solution may further contain an organic resin. On the other hand, from the viewpoint of magnetic properties and the like, it is preferable that the film of the electromagnetic steel sheet is thin, and it is more preferable that the film does not have a film. From this point of view, it is preferable that the electromagnetic steel sheet used for the transformer of the present invention does not have a tension coating.
The electromagnetic steel sheet used for the transformer of the present invention is preferably one having a surface oxide layer from the viewpoint of suppressing an overcurrent generated in the stacking direction and having excellent magnetic characteristics.

In the transformer of the present invention, the size of the wound iron core 1 is not particularly limited, and can be a desired size depending on the application. For example, the length of the iron core (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 (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 of the electromagnetic steel sheet constituting the iron core (the length in the Y-axis direction in FIG. 1) can be 10 mm or more and 400 mm or less, and preferably 20 mm or more and 300 mm or less. Further, the laminated thickness of the laminated body constituting the iron core can be 10 mm or more and 200 mm or less, and preferably 20 mm or more and 150 mm or less.
For example, in the case of a 20 kVA transformer, a wound iron core having a central window portion of 140 mm × 70 mm, a laminated thickness of 60 mm, and a plate width of 150 mm can be mentioned as a preferred embodiment.
Further, as another configuration of the wound iron core, a known configuration generally used as a wound iron core for a transformer can be used.

Further, 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 supply and a secondary coil connected to a take-out circuit. The material of the winding is not particularly limited, and examples thereof include copper and aluminum. The winding configuration can be a known configuration generally used for transformers. Further, as another configuration of the transformer, a known configuration generally used for the transformer can be used.

The present invention is not limited to the above embodiment. The above-described embodiment is an example, and any object having substantially the same configuration as the technical idea described in the claims of the present invention and exhibiting the same effect and effect is the present invention. Is included in the technical scope of.
Hereinafter, the present invention will be specifically described with reference to examples. These descriptions do not limit the present invention.

(Manufacturing of transformer 1)
A wound steel core having a joint was produced using a grain-oriented electrical steel sheet. This grain-oriented electrical steel sheet has a tension film containing phosphate and colloidal silica as main components on its surface. Next, the joint portion was opened once, the end portion of the opened wound iron core was inserted into the winding, and the joint portion was rejoined. The two legs and the two yokes of the wound iron core are each provided with a pressure member that pressurizes in the laminating direction of the electromagnetic steel plate, and a tension applying member that applies tension in the circumferential direction to the legs of the wound iron core. Was provided to prepare the transformer 1 shown in the example of FIG.

(Preparation of transformer 2)
In the production of the transformer 1, the transformer was made in the same manner as the transformer 1 except that the grain-oriented electrical steel sheet having a surface oxide layer and no tension film was used instead of the grain-oriented electrical steel sheet having a tension film. 2 was prepared.

(Evaluation of iron loss)
The pressure in the stacking direction and the tension in the circumferential direction of the produced transformers were adjusted to the combinations shown in Table 1, and the iron loss was evaluated for each. The iron loss reduction rate in Table 1 is No. It is a value calculated by the following formula based on the iron loss value of 1.
Iron loss reduction rate (%) = (P _1- P) / P ₁ x 100
(In the formula, P ₁ represents the iron loss value in No. ₁ of Table 1, and P represents the iron loss value under each condition in Table 1.)

[Summary of results]
As shown in Table 1, it was clarified that the iron loss was reduced by applying tension in the circumferential direction of the wound iron core and pressurizing in the laminating direction of the electromagnetic steel sheets constituting the wound iron core. No. 1-No. From the comparison of No. 7, it was clarified that the iron loss was further reduced by increasing the tension in the circumferential direction. In addition, No. 9 to No. From the comparison of No. 12, it was clarified that the iron loss was further reduced by increasing the compressive force in the stacking direction. In addition, No. 5 and No. From the comparison with No. 13, in the wound steel core of the present invention having a tension applying member for applying tension in the circumferential direction, a transformer having a surface oxide layer can be used to manufacture a transformer in which iron loss is further suppressed. Became clear.

1 Winding iron core 2a, 2b Winding 3 Joint 4 Pressurizing plate 4a Pressurizing plate and tension applying plate 5 Pressurizing bolt 6 Pressurizing nut 7 Tension applying stud bolt 8 Tension applying nut

Claims (4)

A rectangular annular wound iron core made of a laminated body of electrical steel sheets and having a joint,
A winding wound around at least one of the columnar portions of the wound iron core,
A pressure member that is arranged in each of all the columnar portions of the wound steel core and pressurizes the columnar portions in the laminating direction of the electromagnetic steel sheet, and
A tension applying member that applies tension in the circumferential direction to at least one columnar portion of the wound iron core is provided.
Each of the pressurizing members is arranged on both sides of the columnar portion in the stacking direction, and has a rectangular shape along the outer circumference of the columnar portion, and a pressurizing plate for tightening the pressurizing plate from both sides in the stacking direction of the columnar portion. Equipped with bolts and pressurizing nuts
Of the pressurizing plates arranged in the window portion of the columnar portion, at least a pair of pressurizing plates arranged at facing positions in the window portion are selected as the pressurizing and tensioning plates.
The tension applying member includes at least a pair of the pressurizing and tension applying plates arranged at facing positions in the window portion of the columnar portion, and a tension applying stud bolt connecting the pair of pressurizing and tension applying plates. A transformer comprising a pair of tension applying nuts arranged at both ends of a tension applying stud bolt. The transformer according to claim 1, wherein the pressing force of the pressurizing member is 0.1 MPa or more. The transformer according to claim 1 or 2, wherein the electromagnetic steel sheet does not have a tension coating. The transformer according to any one of claims 1 to 3, wherein the electromagnetic steel sheet has a surface oxide layer.