JP2007242844A - Laminated core excellent in dimensional accuracy and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for stably manufacturing a laminated core excellent in dimensional accuracy with improved productivity, and to provide the laminated core manufactured according to this method. <P>SOLUTION: For example, two holes for registration are provided in a soft magnetic steel plate when the soft magnetic plate is stamped into a predetermined shape. Then, when a plurality of the soft magnetic steel plates are laminated, rivets are inserted into the holes for registration, and the lamination is fixed while adjusting the squareness thereof to obtain the laminated core. Usually, the subsequently carried out steps of impregnating the lamination with an adhesive, molding it by restraining it with a molding jig, and carrying out drying and baking treatment, can be omitted. Further, the lamination is rotated about the rivet inserted into the hole for registration before fixing the lamination to remove the iron powder occurred on the stamped surface to prevent the occurrence of a clearance between the laminated cores. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a laminated core used for a reactor iron core and the like, and a laminated core produced thereby.

  Punching of a thin steel plate serving as an iron core of an electric device or the like is performed by a method of punching in a state where the iron plate is crimped and integrated by a press.

  However, the method of processing by caulking cannot be used for thin steel plates having a plate thickness of 0.2 mm or less due to the fact that the crimping strength of the caulking portion is weak and cannot be used sufficiently. . Also, a soft magnetic steel sheet having Si: 4.0% or more cannot be used because the material becomes brittle.

  Therefore, when a laminated core is manufactured using a thin steel plate having a thickness of 0.2 mm or less or a soft magnetic steel plate having Si: 4.0% or more, a laminated adhesion method is employed. This lamination bonding method is a method in which, for example, a soft magnetic steel sheet is first punched into a predetermined shape, then a plurality of layers are laminated, and the obtained laminate is fixed with a jig.

  However, since the laminated adhesive method has many parts that rely on manual work, the productivity is poor and the processing cost is high. In order to reduce the processing cost, there is a problem in that the perpendicularity of the product core is deteriorated and the dimensional system is deteriorated even if they are bonded in the press die.

Under these circumstances, the present inventors, as a method for producing a laminated core that solves the above-mentioned problems, laminated a plurality of punched soft magnetic steel plates (also called bulk cores), On the other hand, a method is proposed in which drying and baking are performed after impregnating an adhesive, using a fluororesin coating plate as a release material, constraining with a molding jig and molding (Patent Document 1).
However, even with Patent Document 1, it is difficult to manufacture a laminated core having excellent dimensional accuracy with high productivity.

On the other hand, when a soft magnetic steel sheet is punched into a predetermined shape by a press, iron powder is generated on the punched surface, which may enter between the laminated cores and cause gaps between the laminated cores. If a gap is generated between the laminated cores, the space factor is lowered, so that the magnetic characteristics are deteriorated. In addition, when pouring high-temperature resin between laminated cores in a resin mold (hereinafter referred to as potting) that is used for bonding in subsequent processes, joining cores or preventing noise of the entire reactor, The core will break. In particular, high silicon steel sheets with a Si content of 4.0% or more are brittle, and iron powder is easily generated.
Japanese Patent Laid-Open No. 2005-19640

  In view of the above circumstances, an object of the present invention is to provide a method for stably producing a laminated core having excellent dimensional accuracy with high productivity and a laminated core produced by the method.

  The present inventors have intensively studied to solve the above problems. As a result, using rivets when fixing the laminate is effective for improving dimensional accuracy. When using rivets, positioning holes are provided in the soft magnetic steel plate in advance, and rivets are provided in the positioning holes. It has been found that a laminated core with excellent dimensional accuracy can be obtained without deteriorating productivity by being inserted. It has also been found that the iron powder generated on the press punched surface can be removed by rotating the laminate around the rivet inserted into the positioning hole. For example, by rotating the laminated body with rivets as fulcrums and using centrifugal force at this time, iron powder that caused gaps between the laminated cores is completely removed, preventing deterioration of magnetic properties Is done.

The present invention has been made based on the above findings, and the gist thereof is as follows.
[1] In a method for producing a laminated body and a laminated core by laminating a plurality of soft magnetic steel plates obtained by punching into a predetermined shape, positioning holes are provided in the soft magnetic steel plates, and the plurality of the laminated laminates are laminated. In this case, a method for manufacturing a laminated core having excellent dimensional accuracy, wherein a rivet is inserted into the positioning hole and the laminated body is fixed.
[2] A method for producing a laminated core with excellent dimensional accuracy, wherein, in [1], after the laminated body is fixed with rivets, the laminated body laminated portion is bonded with an adhesive.
[3] A method for producing a laminated core having excellent dimensional accuracy, wherein, in [1] or [2], the soft magnetic steel plate is a high silicon steel plate having an Si content of 4.0 mass% or more.
[4] In any one of [1] to [3], the thickness of the soft magnetic steel plate is 0.2 mm or less, and the method for producing a laminated core having excellent dimensional accuracy.
[5] In any one of the above [1] to [4], before fixing the laminated body, the laminated body is rotated with the rivet inserted into the positioning hole as a fulcrum, and the iron powder generated on the punched surface The manufacturing method of the lamination | stacking core excellent in the dimensional accuracy characterized by removing this.
[6] A laminated core produced by the method for producing a laminated core according to any one of [1] to [5].

According to the invention, a laminated core can be manufactured at low cost with high production efficiency and high dimensional accuracy. Furthermore, the laminated core of the present invention is completely free of iron powder and the like that caused gaps between the laminated cores, and therefore has no core cracking and excellent magnetic properties.
In particular, the manufacturing method of the present invention is a very effective method for a thin material having a thickness of 0.2 mm or less and a high silicon steel plate having an Si content of 4.0 mass% or more.

  Below, the manufacturing method of the lamination | stacking core of this invention is demonstrated in detail later on process.

A soft magnetic steel plate is used as a punching material and punched into a predetermined shape. From the viewpoint of productivity, it is desirable to use a strip-shaped steel plate (also referred to as a steel strip) as a material steel plate to be punched, and to perform continuous punching by press using a press machine.
In the present invention, from the viewpoint of productivity, it is preferable to provide positioning holes for inserting rivets in the soft magnetic steel sheet when punching. For example, in a punching process using a press, a hole for positioning may be formed in a steel strip, and then punched into a predetermined shape. Specifically, the above-mentioned hole forming die and the punch are punched into one press machine. For example, a metal mold may be set, and hole formation in a soft magnetic steel sheet and punching of a predetermined shape may be continuously performed. Moreover, although productivity is slightly inferior, after punching into a predetermined shape, holes may be formed in a separate process before lamination.
In this way, by making a positioning hole in the soft magnetic steel sheet, inserting a rivet into the hole, and fixing the laminated body, a laminated core having excellent squareness accuracy can be obtained with high production efficiency.

Although one or more positioning holes are provided in the laminated core, it is preferable to provide two or more holes in order to prevent misalignment of the laminated body and improve positioning accuracy.
The rivet hole diameter is preferably as small as possible so as not to disturb the magnetic path. For example, when using a high silicon steel sheet with a plate thickness of 0.10 mm and a Si content of 6.5 mass% and trying to manufacture an I-shaped core, the rivet hole diameter is about 2 to 10 mm, depending on the core size. preferable.
The outer diameter of the rivet is preferably as small as possible with respect to the hole.
Further, the drilling position is not particularly limited, but may be set as appropriate so that a gap is not formed between the laminated steel sheets and the shape of the laminated body can be maintained. In the above case, it is preferable to perform positioning so as to be symmetrical with respect to the center line in the plate width direction or the plate length direction.

Next, after punching, a predetermined number of soft magnetic steel plates (bara cores) provided with positioning holes are laminated to form a laminate. At this time, rivets are inserted into the positioning holes so that the punched individual soft magnetic steel plates do not fall apart, and the laminated body is fixed to adjust the squareness accuracy. The material of the rivet to be inserted into the hole is not particularly specified, but any material having strength for maintaining the core shape may be used. Examples include aluminum rivets. Further, an insulator is more preferable.
The final product may be obtained at the stage of fixing with the rivets, or the final product may be obtained by further infiltrating the entire laminate with the adhesive positioned and temporarily fixed with the rivets.
When a final product is obtained at the stage of fixing with rivets, it is preferable to apply an adhesive to the laminated portion of the laminate, and dry and bake. By applying the adhesive to the laminated portion, the squareness accuracy is further improved.
At this time, the type of adhesive used is not particularly limited. Moreover, although it is preferable that the adhesive is hardened by a drying and baking process, it does not necessarily need to be hardened completely, and it should just be hardened until a certain amount of adhesive strength is obtained. It is also possible to use an adhesive that provides a certain level of adhesive strength within a relatively short time. The amount to be applied is adjusted depending on the size and thickness of the core. The drying and baking temperature is preferably 100 ° C. to 200 ° C., 10 minutes or more and 3 hours or less. When an instantaneous adhesive is used as the adhesive, baking can be omitted depending on the core dimension conditions and the like.

When the laminate is positioned and temporarily fixed with rivets and the entire laminate is further impregnated with the laminate, a method of impregnation using atmospheric capillary action (atmospheric pressure impregnation method) or vacuum is used. Examples of the impregnation method. However, when the laminate is put into an adhesive and impregnated, the method of placing the laminate and the adhesive in a tray or the like and impregnating at normal pressure is about 1/5 to 4/5 at the bottom of the laminate. It shall be immersed in the adhesive. When the laminate is immersed in the adhesive so as to cover the entire laminate, the adhesive penetrates from all sides, and air accumulates in the central portion of the laminate, which adversely affects the core strength. In the method of vacuum impregnation, it is necessary to completely immerse the laminate in the adhesive.
At this time, as the adhesive to be used, a thermosetting adhesive is preferable. In particular, a thermosetting adhesive of acrylic resin or epoxy resin is preferable. For example, when used in automotive parts, etc., since it is used while undergoing a heat cycle from below zero to about 150 ° C., adhesive strength against temperature changes is required, and as a one-component acrylic system as an adhesive It is preferable to use an adhesive or an epoxy adhesive.
Next, the laminated body impregnated with the adhesive is dried and baked to obtain a laminated core in which the soft magnetic steel strips are completely bonded. For the drying and baking treatment, for example, an electric furnace, a hot air drying furnace, an induction heating furnace, or the like can be used. The drying and baking treatment at this time is usually preferably performed at 100 to 200 ° C. for 10 minutes or longer.

  In the present invention, the composition of the soft magnetic steel sheet after punching is not particularly limited, and high silicon steel sheets and amorphous thin steel sheets having a Si content of 4.0 mass% or more can be used without any problems. .

  Further, the thickness of the soft magnetic steel sheet after punching is not particularly limited, but is particularly suitable for a soft magnetic steel sheet having a thickness of 0.2 mm or less, particularly 0.15 mm or less, which is difficult to be caulked. Then, such a very thin steel plate can be used without any problem.

(Example of the present invention)
The manufacturing process of the example of the present invention is shown in Table 1.
A 6.5% silicon steel sheet having a thickness of 0.1 mm and a material width of 60 mm was used, and the punching length (cutting length) was 30 mm by stamping. At this time, as shown in FIG. 1, positioning holes for inserting rivets were provided in two places. When providing the holes, the hole diameter is 4 mm, the rivet outer diameter is 3.6 mm, and the position of the hole is symmetric with respect to the center line in the plate width direction at a position of one third of the hoop width ( 20 mm from the end in the width direction).
Next, rivets were inserted into the positioning holes, a predetermined number of layers were stacked, and the squareness accuracy was adjusted and fixed as a layered product to produce a layered core (width 60 mm, length 30 mm, stacking thickness 40 mm) shown in FIG. As the rivet, an aluminum rivet was used.

(Comparative example)
Using the same material as that of the above-described example of the present invention, punching was performed in the same manner. Next, a laminated core was manufactured by the process shown in Table 1. In manufacturing, an acrylic adhesive was used as the adhesive, and drying and baking were performed at 150 ° C. for 90 minutes.
When the dimensional accuracy was measured as a core inspection for the laminated cores of the present invention example and the comparative example obtained as described above, the comparative example and the present invention example showed equivalent dimensional accuracy of 1% or less of the perpendicularity. As shown in FIG. 2, the dimensional accuracy is obtained by calculating the squareness a / b using the thickness a in the stacking direction of the laminate and the maximum gap b between the side surface of the laminate and the perpendicular surface of the perpendicular gauge. Evaluation was made using the value of / b (multiplied by 100 and expressed in%).

  From Table 1, in the example of the present invention, although the dimensional accuracy is equivalent, the steps are greatly omitted compared to the comparative example. Thus, it can be seen that the cost can be reduced by largely omitting the steps while maintaining the dimensional accuracy.

(Example of the present invention)
The manufacturing process of the example of the present invention is shown in Table 2.
A 6.5% silicon steel sheet with a thickness of 0.1 mm and a material width of 80 mm was used, and a U-shaped punching process was performed with total blanking. At this time, as shown in FIG. 3, positioning holes for inserting rivets were provided in two places. In addition, when providing a hole, the hole diameter was 5 mm, the rivet outer diameter was 4.6 mm, and the drilling position was the position shown in FIG.
Next, rivets are inserted into the positioning holes, a predetermined number of layers are laminated and temporarily fixed as a laminated body, then vacuum impregnated with an acrylic adhesive, and dried and baked at 150 ° C. for 2 hours. The laminated core shown in 3 was manufactured. As the rivet, an aluminum rivet was used.

(Comparative example)
As a comparative example, punching was performed in the same manner using the same material as in Example 2 and the present invention. Subsequently, the laminated core was manufactured according to the process shown in Table 2. In manufacturing, an acrylic adhesive was used as the adhesive, and drying and baking were performed at 150 ° C. for 2 hours.
When the dimensional accuracy was measured as a core inspection for the laminated cores of the present invention example and the comparative example obtained as described above, the comparative example and the present invention example showed the same dimensional accuracy of 1% or less of the perpendicularity. The dimensional accuracy was measured by the same method as in Example 1.

  From Table 2, in the example of the present invention, although the dimensional accuracy is equivalent, the process is greatly omitted as compared with the comparative example. Thus, it can be seen that the cost can be reduced by largely omitting the steps while maintaining the dimensional accuracy.

(Example of the present invention)
A 6.5% silicon steel sheet having a thickness of 0.1 mm and a material width of 80 mm was used, and as shown in FIG. At this time, as shown in FIG. 3, positioning holes for inserting rivets were provided in two places. In addition, when providing a hole, the hole diameter was 5 mm, the rivet outer diameter was 4.6 mm, and the drilling position was the position shown in FIG.
Next, after inserting a rivet into one of the positioning holes and laminating a predetermined number of layers to form a laminated body, the laminated body was rotated using this rivet as a fulcrum, and the iron powder on the pressed surface was removed by centrifugal force. . After that, insert a rivet into the remaining one of the positioning holes, adjust the squareness accuracy and temporarily fix it, then vacuum impregnate with acrylic adhesive, and dry and bake under conditions of 150 ° C x 2 hours A laminated core was produced. As the rivet, an aluminum rivet was used.

(Comparative example)
As a comparative example, in the above Example 3 and the present invention example, without rotating the laminated body with the rivet as a fulcrum (without removing iron powder by centrifugal force), the other examples are the same as Example 3 and the present invention example. Lamination and cores were made in the same manner.
The laminated cores of the present invention and the comparative example obtained as described above were visually inspected for whether or not a gap was generated between the laminated cores. It should be noted that a gap occurred when the gap length formed on the laminated surface between the laminated cores was 5 mm or more.
As a result, no gap was generated in the example of the present invention, and a gap was generated in the comparative example. As described above, in the present invention example, the generation of a gap between the laminated cores was prevented by removing the iron powder, thereby preventing the core cracking in the subsequent process or potting.

  Since the laminated core of the present invention has excellent magnetic properties and excellent dimensional accuracy, it can be used in various applications, mainly iron core materials such as electrical equipment.

It is a perspective view which shows the laminated body after a punching process and before rivet insertion. Example 1 It is a figure which shows the perpendicularity of the lamination surface and side surface of a laminated body. (Examples 1 and 2) It is a perspective view which shows the laminated body after a punching process and before rivet insertion. (Examples 2 and 3)

Claims (6)

In a method of manufacturing a laminated core and a laminated core by laminating a plurality of soft magnetic steel plates obtained by punching into a predetermined shape,
A positioning hole is provided in the soft magnetic steel sheet,
A method for manufacturing a laminated core having excellent dimensional accuracy, wherein, when the plural sheets are laminated, a rivet is inserted into the positioning hole to fix the laminated body.   The method for producing a laminated core with excellent dimensional accuracy according to claim 1, wherein the laminated body is bonded with an adhesive after the laminated body is fixed with a rivet.   The method for producing a laminated core with excellent dimensional accuracy according to claim 1 or 2, wherein the soft magnetic steel sheet is a high silicon steel sheet having an Si content of 4.0 mass% or more.   The method for producing a laminated core with excellent dimensional accuracy according to any one of claims 1 to 3, wherein the thickness of the soft magnetic steel sheet is 0.2 mm or less.   Before fixing a laminated body, a laminated body is rotated by using the rivet inserted in the positioning hole as a fulcrum, and the iron powder generated on the punching surface is removed. The manufacturing method of the laminated core excellent in the dimensional accuracy of description.   The laminated core manufactured by the manufacturing method of the laminated core in any one of Claims 1-5.

Images