KR200388289Y1 - iron core, molding for forming and mounting iron core - Google Patents

Abstract

When molding core iron cores used in transformers, rectifiers, ballasts, lamps, etc., "E" shaped core iron cores are extracted from the silicon steel sheet, and the raw materials located on the left and right sides are combined with "eccentric c" shaped core iron cores. The core iron core can be molded without scraping as it is cast out, and at the same time, the "E" shape and the "eccentric" shape core iron cores, which are each formed in a sheet, can be laminated in a predetermined number of sheets without a separate subsequent process.

Core core according to the present invention, E-shaped core iron core including a protrusion formed symmetrically on both sides, and a coupling protrusion formed between the protrusion and the coiled bobbin is coupled,

A projection groove corresponding to the projection is formed, and a projection corresponding to the projection groove between the projection and the engaging projection is formed, and has a pair of C-shaped core iron cores having an eccentric cross-sectional shape.

The injection molding of the E-shaped core iron core from the silicon steel sheet, but by combining the raw materials located on the left and right sides of the E-shaped core core core with the eccentric C-shaped core core, the core core can be cast out without scrap.

Description

Core core, molding for forming and mounting iron core

The invention devises that when core core is punched out of thin silicon steel sheet by press mold, it is "eccentric" c-shaped core iron core and "E" shape without loss of raw materials (referring to scrap). The present invention relates to a core iron core capable of continuously forming and laminating core iron cores, and a mold for molding and laminating the core iron cores.

More specifically, when forming the core core used in transformers, rectifiers, ballasts, lamps, etc., the "E" shaped core iron core is extracted from the silicon steel sheet, and the raw materials located at the left and right sides thereof are "eccentric c" shaped. The core cores can be molded without scraping by combining with core cores, and at the same time, the "E" shaped and "eccentric" shaped "core" cores respectively formed into sheets can be laminated in a predetermined number of sheets without a separate subsequent process. It relates to a core iron core, a mold for molding and laminating it.

As shown in FIG. 1, the core core according to the prior art has a shape corresponding to the shape of a press die (not shown) having a predetermined shape in a silicon steel sheet 1 of a thin plate to be fed continuously (core core shape). And a die having a " c " shape as a scrap 3 except for the core iron core 2 formed from the silicon steel sheet 1; The core part (2) is built-in because the surplus part (referred to the space located in the left and right direction and the vertical direction of the adjacent core iron core (2)) is generated and the cost cost is increased due to the expensive silicon steel sheet. There is a problem in that the price competitiveness of the product (which refers to transformers, etc.) is poor.

In addition, in order to laminate and use the core iron cores 2 formed as described above in a predetermined number of sheets, a separate subsequent step of laminating the punch-molded core iron cores 2 and fusion welding the core iron cores 2 by argon welding or the like. In addition, the workability and productivity are reduced, and the core iron core (2) welded portion cuts off the flow of electrical characteristics, or the welded portion acts as one interference factor, thereby degrading the electrical characteristics. This has the problem of falling.

On the other hand, as shown in Figure 2, the E-type and I-type core core according to the prior art, the "E" shaped core from the silicon steel sheet 1 using one mold punch and die (not shown) Press-molding the iron core 4 and the "I" -shaped core iron core 5 has the advantage of preventing the waste of the scraped silicon steel sheet 1 to be wasted to reduce the cost cost.

On the other hand, the pitch spacing L of the press mold for punching out the above-mentioned "E" -shaped core iron core 4 and "I" -shaped core iron core 5 is long, so that the overall size of the mold punch and the die die is increased. As a large press is used to form the core core, the press punching speed is lowered, which leads to problems in productivity and competitiveness.

Further, the core iron core from the above-described silicon steel sheet 1 is punched out to form an E-shaped core iron core 4, while one E-shaped core core 4 is punched out in the upward direction, while the other E As the female core iron core 4 is cast in the downward direction, the work of taking out the projected E-shaped core iron core 4 from the mold die is cumbersome, resulting in poor workability.

The object of the present invention is that, as the core iron core which is formed by injection molding from the silicon steel sheet by the press mold is formed by combining the "eccentric" and "E" shapes, the expensive silicon steel sheet is scraped and wasted. The present invention provides a core iron core, core iron core molding, and a stacking mold for preventing cost and reducing cost costs to make a price competitive.

Another object of the present invention is that by punching out the core iron core from the silicon steel sheet by the die punch and the die die in a downward direction, the core molded core can be easily taken out from the mold die, thereby improving workability. To provide a core iron core, core iron core molding, lamination dies that can be made.

Another object of the present invention is to core the core core in a certain number of sheets without additional processing in the case of forming the core core from the silicon steel sheet to improve the workability and productivity by reducing the labor time To provide iron core molding and lamination dies.

Another object of the present invention is to reduce the pitch spacing of the press mold for punching core core to reduce the size of the press mold and die to increase the press punching speed according to the use of a small press to improve productivity and competitiveness To provide a core core, core core molding, lamination dies.

It is another object of the present invention to improve the electrical properties of the core core by improving the core characteristics of the core core since it is unnecessary to carry out the fusion-fixing process for laminating the core cores to be formed separately, and the magnetic flux density is relatively higher than that of the E and I core cores. To improve the reliability of the core iron core molding, laminating dies to provide.

An object of the present invention described above, E-shaped core iron core including a protrusion formed symmetrically on both sides, and a coupling protrusion formed between the protrusions and the coiled bobbin is coupled,

A projection groove corresponding to the projection is formed, and a projection corresponding to the projection groove between the projection and the engaging projection is formed, and has a pair of C-shaped core iron cores having an eccentric cross-sectional shape.

Core-core core, characterized in that injection molding E-shaped core iron core from a silicon steel sheet, and the core core can be molded without scraping by combining the raw materials located on the left and right sides into eccentric C-shaped core core. By providing.

The object of the present invention described above is in a mold for molding and laminating a core iron core from a thin sheet of silicon steel,

Embossing punches to form the embossed portion to be laminated in close contact with the core core, a pair of C-shaped core iron core punches having the bottom-shaped press punch punched out to form the eccentric C-shaped core iron core, and the C-shaped core A mold punch comprising an E-shaped core iron core punch having an injection-molded silicon steel sheet material between the iron cores with an E-shaped core iron core and having a pressurization punch on the bottom;

A recess corresponding to the punch for embossing, a first seat formed in a shape corresponding to the punch for the C-shaped core iron core, and stacked in a shape of the punched-shaped C-core core, and corresponding to the punch for the E-shaped core iron core And a mold die including a second seating portion which is formed in the shape and formed by stacking an E-shaped core iron core which is formed by stacking,

Combination of C-shaped core iron core and E-shaped core iron core eccentric from silicon steel sheet prevents scrap of silicon steel sheet according to injection molding, and prevents scrapping of silicon steel sheet and accumulates individually and accumulates in the first and second seating parts It is achieved by providing a core iron core forming and laminating die, wherein the embossing portion is pressed by a lamination pressure punch to laminate the core iron cores in a predetermined number of sheets.

According to a preferred embodiment, the silicon steel sheet conveyed on the mold die is pressed downward by a mold punch to punch out an E-shaped core core and an eccentric C core core.

The object of the present invention described above is a lamination method for laminating core iron cores that are molded by press molds from thin silicon steel sheets.

A first step of forming the embossed portion on the silicon steel sheet;

A pair of C-shaped core iron cores are symmetrically cut out from the silicon steel sheet by punches and dies for C-shaped core iron cores that correspond to eccentric core cores eccentric to prevent the occurrence of scrap during core molding. A second step of forming and casting out the E-shaped core iron core from the silicon steel sheet in which the U-shaped core iron core is punched out by a punch and a die for the E-shaped core iron core having a shape corresponding to the E-shaped core iron core;

A third step of accumulating the U-shaped core cores and the E-shaped core cores which are projected from the first seating portion and the second seating portion formed in the die in a shape corresponding to the U-shaped core core and the E-shaped core core;

The core cores are stacked in a predetermined number by pressing the lamination pressure punch formed on the bottom surface of the punches for the U-shaped and E-shaped core iron cores, respectively. It is achieved by providing a method for forming and laminating the core core, characterized in that it comprises a fourth step to make.

According to a preferred embodiment, the coupling yaw portion formed in the engaging projection of the E-shaped core iron core and the yaw is a means for coupling a pair of C-shaped core iron cores eccentric with respect to the aforementioned E-shaped core iron core. Coupling iron parts formed and fitted into protrusions of the U-shaped core iron core, coupling iron portions respectively formed on the protrusions of the E-shaped core iron core, and E-shaped core iron cores. It includes a coupling yaw portion that is formed and fitted to the extension projections extending to the projections of the U-shaped core iron core so as to correspond to the iron portion.

In addition, two rows, four rows of mold punches and mold dies can be simultaneously formed into two pairs, four pairs, six pairs, and eight pairs of C-shaped core cores and E-shaped core cores which are eccentric from the aforementioned silicon steel sheet. It can be arranged in 6 rows and 8 rows.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings, which are intended to be described in detail so that those skilled in the art to which the present invention pertains can easily implement the present invention. It does not mean that the technical spirit and scope of the present invention is limited.

As shown in FIGS. 3 to 6, the core iron core according to the present invention is a core iron core from a silicon steel sheet 17 of a thin plate having a predetermined thickness (generally, 0.5 mm, or 0.1 to 0.35 mm is used). In the case of injection molding with a press die (not shown), the eccentric core core 16 and the eccentric core core 12, which are eccentric so as to prevent the silicon steel sheet 17 from being scrapped and wasted, are formed. Combination molding is performed.

That is, the aforementioned core iron core has a protrusion 10 which is formed symmetrically on both the left and right sides, a coupling protrusion 11 formed between the left and right protrusions 10 and a bobbin (not shown) wound around the coil, and a protrusion. An E-shaped core iron core 12 including a launch groove 14 formed between the 10 and the engaging projection 11 is provided.

In addition, the core core described above is formed with a projection groove 13 corresponding to the projection 10, and a projection 15 corresponding to the projection groove 14 between the projection 10 and the engaging projection 11 is formed. As the extension protrusions 22 asymmetrically extending on the protrusions 15 are formed to have a relatively longer length than the protrusions 15, the cross-sectional shape is eccentric and the pair of eccentric c-shaped having a c-shape formed asymmetrically. The core iron core 16 is provided.

At this time, as a means for coupling a pair of c-shaped core iron core 16 eccentric to the above-described E-shaped core iron core 12, the coupling yaw formed in the engaging projection 11 of the E-shaped core iron core 12 ( A convex portion 19 formed on the projection 15 of the c-shaped core iron core 16 so as to correspond to the concave portion 18, and fitted to each other; C-shaped cores so as to correspond to the convex portions 20 formed on the protrusions 10 of the E-shaped core iron cores 12 and the convex portions 20 of the E-shaped core iron cores 12. It may include a coupling recess 23 formed in the extension protrusion 22 of the iron core 16 to be fitted to each other.

In the drawings, reference numeral 35 denotes a concave portion that is inevitably generated in the E-shaped core iron core 12 when the projection 15 of the C-shaped core iron core 16 is cast out from the silicon steel sheet 17. Is a concave portion that is inevitably generated from the silicon steel sheet 17 to the C-shaped core iron core 16 when the projection 10 of the E-shaped core iron core 12 is punched out.

The core iron core forming and laminating mold according to the present invention is formed from a thin sheet of silicon steel sheet 17 by forming a combination of the U-shaped core iron core 16 and the E-shaped core iron core 12 and forming a silicon steel sheet 17. ) And the embossed portion 24 of the E-shaped core iron core 12 and the c-shaped core iron core 16 accumulated in the first and second seating portions 32 and 33 by being blow-molded separately. ), The C-shaped core iron core 16 and the E-shaped core iron core 12 can be laminated as a predetermined number of sheets by pressing the pressing punches 26 and 28 for lamination.

The mold for forming and laminating the core iron core of the present invention has a punching hole 41 for drilling the through hole 50 in the silicon steel sheet 17 and the embossing portion 24 so that the core iron core can be laminated in close contact with each other. A pair of U-shaped core iron core punches 27 having a punching molding of the embossing punch 25 and an eccentric U-shaped core iron core 16 and having a stacking pressing punch 26 on the bottom surface thereof. The silicon steel sheet 17 between the core core cores 16 is punched out with an E-shaped core iron core 12 and includes an E-shaped core iron core punch 29 having a lamination pressure punch 28 on the bottom. A mold punch 30 is provided.

In addition, the mold for forming and stacking the core core of the present invention includes a through hole 42 formed to correspond to the above-described punch hole 41, and a recess 31 formed to correspond to the embossing punch 25. And a first seating portion 32 which is formed in a shape corresponding to the C-shaped core iron core punch 27 and is formed by stacking the molded C-shaped core iron core 16, and an E-shaped core iron core punch 29 ) And a mold die 34 including a second seating portion 33 which is formed in a shape corresponding to) and is formed by stacking an E-shaped core core 12.

In the drawings, reference numerals 39 and 39a are punches and through-holes used for punching out the yaw portion 23 of the C-shaped core iron core 16, and 40 and 40a are E-shaped core iron cores 12. It is a punch and a through-hole used to punch-out the yaw portion 18.

Hereinafter, the core molding according to the present invention will be described in detail with reference to the accompanying drawings.

In detail, when the above-described silicon steel sheet 17 is transferred to the upper surface of the die die 34 by a conveying means (not shown) (shown in phantom in FIG. 4), an eccentric c-shaped core The first seating portion 22 symmetrically formed on the die die 34 in a shape corresponding to the iron core 16 and the U-shaped core iron punch 27 formed in the mold punch 30 in a shape corresponding thereto. As a result, the C-shaped core iron core 16 eccentrically formed from the silicon steel sheet 17 can be press-molded.

On the other hand, the second seat portion 33 formed in the die die 34 in a shape corresponding to the aforementioned E-shaped core iron core 12, and the punch for E-shaped core iron core formed in the mold punch 30 in a shape corresponding thereto (29) By the structure, it is possible to press-cast the E-shaped core iron core 12 eccentric from the silicon steel sheet 17.

That is, as shown in Figures 3 and 6, a pair of c-shaped core iron core 16 eccentric from the silicon steel sheet material 17 using the above-described mold punch 30 and the die die 34, As the injection molding is performed by combining the E-shaped core iron core 12, the cost of the silicon steel sheet 17 can be prevented from being scrapped due to expensive silicon steel sheet 17 when the core iron core is molded from the silicon steel sheet 17, thereby reducing the cost. Can be.

On the other hand, the description of the means for transferring the above-described silicon steel sheet 17, and the means for driving the mold punch 30 and the die die 34 is technically used in the art, so these detailed descriptions Is omitted.

With reference to the accompanying drawings, forming and laminating the core iron core by using the core iron core forming and laminating mold according to the present invention will be described in detail.

As shown in FIGS. 4 to 6, when punching out the core core from the silicon steel sheet 17, the predetermined number of C-shaped core iron cores 16 and E-shaped core iron cores 12 that are separately cast out is prescribed. As a result of stacking and stacking, the workability and productivity can be improved.

In detail, when the above-described silicon steel sheet 17 is transferred to the upper surface of the die die 30 (shown in phantom in FIG. 4), the through hole punch 41 formed in the mold punch 30 and The through hole 42 formed in the die die 34 has a shape corresponding to that formed in the silicon steel sheet 17 so as to prevent the embossing portion 24 from being unfolded when the core hole is punched out. Will be formed).

The recessed part formed in the extension protrusion 22 of the U-shaped core iron core 16 by the punch 39 formed in the above-described mold punch 30 and the through hole 39a formed in the mold die 34 in a shape corresponding thereto. Injection molding (23). At the same time, a recess formed in the engaging projection 11 of the E-shaped core iron core 12 by the punch 40 formed in the mold punch 30 and the through hole 40a formed in the mold die 34 in a shape corresponding thereto ( 18) Mold out by molding.

The embossing portion 24 is formed on the silicon steel sheet 17 by the embossing punch 25 formed in the above-described mold punch 30 and the recess 31 formed in the mold die 34 in a shape corresponding thereto. .

The silicon steel sheet 17 is formed by the U-shaped core iron core punch 27 formed in the above-described mold punch 30 and the first seating portion 32 symmetrically formed on the mold die 34 in a shape corresponding thereto. From the eccentric C-shaped core iron core (16) is punched out.

At this time, the recessed part 35 is punched out in the punching groove 14 of the E-shaped core iron core 12 by the projection 27a structure of the C-shaped core iron core punch 27, and at the same time, the punch for the C-shaped core iron core ( The concave portion 20b of the 27 enables the cast-out portion 20 to be formed on the protrusion 10 of the E-shaped core iron core 12.

On the other hand, the embossed portion 24 formed on the U-shaped core iron core 16 accumulated on the first seating part 32 after being cast from the silicon steel sheet 17, the bottom of the U-shaped core iron punch (27) By pressing by the stacking pressure punch 26 for protruding to the surface, the core iron cores formed individually from the silicon steel sheet 17 can be stacked in a predetermined number. At this time, it is a matter of course that the U-shaped core iron core 16 stacked in a predetermined number from the first seating portion 32 of the mold die 30 can be drawn out by the driving means (not shown).

Meanwhile, an E-shaped core iron core punch 29 formed in the mold punch 30 in a shape corresponding to that of the E-shaped core iron core 12 and a second seating portion 33 formed in the mold die 34 in a shape corresponding thereto. By the structure, the E-shaped coil core 12 eccentrically formed from the silicon steel sheet 17 is punched out.

At this time, the embossed portion 24 formed on the E-shaped core iron core 12 accumulated in the second seating portion 33 is applied to the stacking pressure punch 28 formed to protrude on the bottom surface of the punch 29 for the E-shaped core iron core. As a result of pressurization, the E-shaped core iron cores 12 which are individually formed from the silicon steel sheet 17 can be laminated in a predetermined number. In this case, it is a matter of course that the laminated E-shaped core iron core 12 formed from the second seating portion 33 of the mold die 34 may be drawn out by the driving means not shown.

On the other hand, when the embossed portion 24 of the E-shaped core iron core 12 is pressed by the lamination pressure punch 28, the through-hole punch 41 formed in the mold punch 30 and the mold die 34 correspondingly. The embossed portion 24 of the E-shaped core iron core 12 stacked in a predetermined number by a through hole (not shown) formed in the silicon steel sheet 17 by the through hole 42 formed in the Of course it is prevented.

As described above, the? -Shaped core iron core 16 and the E-shaped core iron core 12 which are formed by punching out from the silicon steel sheet 17 individually and accumulated in a predetermined number on the first and second seating portions 32 and 33. ) Can be improved without any fusion process to improve workability and productivity.

In addition, when the above-mentioned E-shaped core iron core 12 and the eccentric U-shaped core iron core 16 are used in combination after punching and lamination, the electrical characteristics generated by increasing the magnetic flux density are shown in FIG. After the core-core core 4 and the I-shaped core core 5 are cut out and laminated, the electrical characteristics are improved when they are used in close contact with each other.

On the other hand, although not shown in the drawing, the C-shaped core iron core 16 and the E-shaped core iron core 12, which are eccentric from the above-described silicon steel sheet 17, are simultaneously typed into two pairs, four pairs, six pairs, and eight pairs. As the mold punch 30 and the die die 34 are arranged in two rows, four rows, six rows, and eight rows to be molded, the cost and cost can be reduced by improving workability and productivity.

In addition, as shown in Figure 7, the core core according to the present invention, by punching out the E-shaped core iron core (12a) from the silicon steel sheet material 17 using the mold punch and mold die (not shown) However, the raw materials located on both the left and right sides thereof may be combined with an eccentric C core core 16a eccentrically using a corresponding mold punch and a die (not shown) to perform injection molding. The E-shaped core iron core 12a described above. After punch-molding the c-shaped core iron core 16a, the core iron core to be laminated can be fused and used.

At this time, the punch-molding operation of the E-shaped core iron core 12a and the C-shaped core iron core 16a from the above-described silicon steel sheet 17 is made substantially the same as that shown in FIG. Description is omitted.

As described above, the core iron core, core iron core molding and lamination die according to the present invention have the following advantages.

By combining the core core core cast out from the silicon steel sheet by the press mold into the "eccentric C" and "E" shapes, the expensive silicon steel sheet is scraped off and wasted, and the cost is reduced. Reduced cost competitiveness

In addition, by increasing the punching speed of the press mold for forming core core cores, the workability and productivity are improved by mass production, and at the same time, the core iron cores are laminated to a predetermined number of sheets without any subsequent steps, thereby reducing the work process.

In addition, as the core iron core is cast out downward from the silicon steel sheet using a mold punch and a die, the molded core core can be easily taken out from the die, thereby improving workability and productivity. .

In addition, the pitch spacing of the press mold for punching out the core core is relatively smaller than that of the press mold for forming the E and I core cores, so that a small press is used, thereby increasing the press punching speed and improving productivity.

In addition, since the subsequent process of fusion-fixing to stack the core cores to be formed separately is unnecessary and the magnetic flux density is relatively higher than that of the E and I core cores, the electrical characteristics of the core cores can be improved to improve the reliability of the product. .

1 is a schematic diagram showing forming a "c" shaped core iron core from a silicon steel sheet according to the prior art;

2 is a schematic view showing forming E-type and I-type core iron cores from a silicon steel sheet according to the prior art;

3 is a perspective view of the core core according to the present invention,

4 is a perspective view of a punch and a die for a press mold used when forming and laminating a core iron core according to the present invention;

5 is a schematic view showing forming an E-shaped core iron core and an eccentric U-shaped core iron core from a silicon steel sheet according to the present invention;

6 is a perspective view of a core core laminated after forming by the present invention;

7 is a modified example of the core core according to the present invention.

* Explanation of symbols used in the main part of the drawing

10; projection part

11; Coupling protrusion

12; E-shaped core iron core

13,14; Home

15; spin

16; T-core core

17; Silicon steel sheet

18,23; Urinary tract

19,20; Iron

22; Extension

24; Embossing department

25; Embossing Punch

26,28; Lamination Press Punch

27; T-shaped core iron punch

29; E-shaped core iron punch

30; Mold Punch

31; Groove

32; First seat

33; Second seat

34; Mold die

Claims (5)

An E-shaped core iron core including a protrusion formed symmetrically on both left and right sides, and a coupling protrusion formed between the protrusions and the bobbin wound around the coil; And A projection groove corresponding to the protrusion is formed, and a projection corresponding to the projection groove between the protrusion and the coupling protrusion is formed, and has a pair of c-shaped core iron cores having a c-shaped cross-sectional shape. Core-core core, characterized in that injection molding E-shaped core iron core from a silicon steel sheet, and the core core can be molded without scraping by combining the raw materials located on the left and right sides into eccentric C-shaped core core. . The method according to claim 1, wherein the pair of eccentric core core eccentric to the E-shaped core core, A coupling recess formed in the engaging projection of the E-shaped core core; A joining iron portion formed and fitted to the protrusion of the c-shaped core iron core so as to correspond to the yaw portion; A joining iron part formed in each of the protrusions of the E-shaped core iron core, Core core, characterized in that it comprises a coupling concave portion formed and fitted to the elongated projection extending to the protrusion of the c-shaped core iron core to correspond to the iron portion of the E-shaped core iron core. In molds for forming and laminating core iron cores from thin silicon steel sheets: An embossing punch for forming an embossing portion so that the core core can be stacked in close contact with the core core, a pair of C-shaped core iron core punches having a bottom press punch for forming an eccentric U-shaped core iron core, and having a pressurizing punch for stacking the core core; A mold punch comprising an E-shaped core iron core punch having an injection-molded silicon steel sheet material between the core cores with an E-shaped core iron core and having a pressurizing punch for lamination on the bottom; And A first seating portion in which a groove corresponding to the embossing punch, a shape corresponding to the C-shaped core iron core punch, and an injection molded C-shaped core iron core are stacked and stacked, and the E-shaped core iron core punch A mold die formed in a corresponding shape and comprising a second seating portion in which an E-shaped core core formed by punching is stacked and stacked; Combining the core core from the silicon steel sheet into an eccentric C-shaped core core and an E-shaped core core to prevent the scraping of the silicon steel sheet according to the injection molding, and separately blow-molding to accumulate each of the first and second seating parts. A core iron core forming and laminating die, wherein the embossed portion of a core iron core is pressed by the lamination pressing punch to laminate the core iron core as a predetermined number. The method according to claim 3, wherein the mold punch and the die die in two rows, so that the C-shaped core core and the E-shaped core core eccentric from the silicon steel sheet can be formed into two pairs, four pairs, six pairs, and eight pairs simultaneously. A core iron core forming and laminating die, characterized in that arranged in four rows, six rows, and eight rows. The core iron core molding according to claim 3 or 4, wherein the silicon steel sheet conveyed on the die is pressurized downward by means of a mold punch to form the E-shaped core core and the E-shaped core iron core eccentrically formed. And lamination molds.