Cylindrical core and method for manufacturing a cylindrical core

Abstract

To provide a cylindrical core with a high yield in terms of material efficiency. [Solution] The cylindrical core 1 is provided with a plurality of partially cylindrical partial cores 2 connected in the circumferential direction C. Each partial core 2 is provided with a plurality of unit cores 4, each having one or more stacked metal plates 3 having the same outer circumference shape, stacked in the axial direction A, with each unit core 4 changing its orientation so that both ends of the circumferential direction C are swapped. Mutually adjacent partial cores 2 have an overlapping portion 6 where each unit core 4 of one partial core 2 and each unit core 4 of the other partial core 2 overlap when viewed in the axial direction A. Each partial core 2 is closely connected to one another via the overlapping portion 6.

Description

Technical Field

[0001] The present invention relates to a cylindrical core including a plurality of circumferentially connected partial cylindrical partial cores and a method for manufacturing the same.

Background Art

[0002] Conventionally, an annular laminated iron core is known, which is configured by arranging split cores divided for each tooth portion constituting a stator in an annular shape with the tooth portion facing the central axis. The split core is formed by laminating a plurality of metal plates (core pieces) having a substantially identical T-shaped configuration by caulking lamination. (See, for example, Patent Document 1)

[0003] According to the method for manufacturing the split core of Patent Document 1, when forming the split core, a plurality of first core pieces in one row arranged in the width direction of the steel plate orthogonal to the feeding direction of the steel plate and a plurality of second core pieces in the other row are simultaneously punched for each row. The punched first core pieces and second core pieces are alternately laminated to form the split core. A plurality of such split cores are connected in the circumferential direction to obtain an annular laminated iron core.

[0004] Here, each of the first and second core pieces has a T-shaped configuration including a back yoke portion extending in the circumferential direction on the outer side in the radial direction and a tooth portion protruding radially inward from the center thereof. The first core piece has a concave shape in which one edge of the back yoke portion extending in the circumferential direction is recessed in the circumferential direction and a convex shape in which the other edge protrudes in the circumferential direction. To conform to this, the second core piece has a convex shape on one edge and a concave shape on the other edge.

[0005] Also, conventionally, a technique for manufacturing a cylindrical core by laminating ring-shaped metal plates punched from a steel plate by caulking lamination or adhesive lamination is known.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

[0007] However, the method for manufacturing a segmented core described in Patent Document 1 is a technique for manufacturing a T-shaped segmented core to obtain a laminated iron core by connecting multiple segments in the circumferential direction. This technique is not suitable for manufacturing a cylindrical core without teeth.

[0008] Furthermore, conventional technology for manufacturing cylindrical cores by stacking ring-shaped metal plates punched out from steel sheets results in a large amount of wasted steel sheet during the manufacturing process, leading to low material efficiency and yield.

[0009] In view of the problems of the prior art, the object of the present invention is to provide a cylindrical core with a high yield in terms of material efficiency and a method for manufacturing the same. [Means for solving the problem]

[0010] The cylindrical core of the present invention comprises a plurality of partially cylindrical partial cores connected in the circumferential direction. Each partial core comprises a unit core having one or more metal plates having the same outer circumference shape stacked together, with each unit core having a different orientation such that the circumferential edges of both ends of each unit core are swapped, and these unit cores are stacked in the axial direction of the cylindrical core.

[0011] Each adjacent subcore has an overlapping portion where each unit core of one subcore and each unit core of the other subcore overlap in the axial direction. Each subcore is closely connected to one another via the overlapping portion. [Effects of the Invention]

[0012] According to the present invention, each metal plate constituting the cylindrical core has the same outer circumference shape, being partially circular and following the partially cylindrical shape of the partial core. Therefore, each metal plate constituting the cylindrical core can be formed by punching out a steel sheet, minimizing material waste. Consequently, a cylindrical core with high material efficiency yield can be provided. [Brief explanation of the drawing]

[0013] [Figure 1] This is a plan view showing a cylindrical core according to the first embodiment of the present invention, as viewed along its axial direction. [Figure 2] Figure 1 is a side view of the cylindrical core. [Figure 3] This figure shows how adjacent sub-cores are connected to each other via an overlapping section in the cylindrical core shown in Figure 1. [Figure 4] This is a side view showing a cylindrical core according to a second embodiment of the present invention. [Figure 5] This figure shows how adjacent sub-cores are connected to each other via an overlapping section in the cylindrical core shown in Figure 4. [Figure 6] This is a plan view of a cylindrical core according to a third embodiment of the present invention. [Figure 7] Figure 7A shows how adjacent subcores are connected via an overlapping portion in the cylindrical core of Figure 6, and Figure 7B shows how adjacent subcores become one unit through the insertion of a pin. [Figure 8] This is a plan view of a cylindrical core according to a fourth embodiment of the present invention. [Figure 9] Figure 9A is a cross-sectional view along line IX-IX in Figure 8, Figure 9B shows a method for forming the crushed portion in this cross-section, Figure 9C shows another method for forming the crushed portion, and Figure 9D shows a method for preventing slight protrusions from both end faces of the pin in the embodiment of Figure 6. [Figure 10] This is a plan view of a cylindrical core according to a fifth embodiment of the present invention. [Figure 11]It is a perspective view showing the shape of one end portion in the circumferential direction of the partial core of the cylindrical core of FIG. 10. [Figure 12] FIG. 12A is a plan view of a part of the cylindrical core according to the sixth embodiment of the present invention, and FIG. 12B is a perspective view showing the shape of one end portion of the partial core of this cylindrical core. [Figure 13] It is a plan view showing the cylindrical core according to the seventh embodiment of the present invention. [Figure 14] FIGS. 14A to 14C are views showing a state in which adjacent partial cores of FIG. 13 are connected using through holes and pins to form a cylindrical core. [Figure 15] It is an explanatory view for explaining a partial core manufacturing apparatus used for manufacturing the partial core according to the first and second embodiments. [Figure 16] FIGS. 16A to 16D are views showing procedures for forming a cylindrical core by combining partial cores. [Figure 17] FIGS. 17A to 17C are views showing modified examples in which chamfered portions extending along the radial direction are provided in the partial cores of FIGS. 3, 5, and 7A, respectively, and FIG. 17D is a view showing a method of forming the chamfered portions.

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a state in which the cylindrical core 1 according to the first embodiment of the present invention is viewed along the axial direction A (see FIG. 2), which is the direction along its central axis. FIG. 2 shows a state in which this cylindrical core 1 is viewed from the side.

[0015] As shown in FIGS. 1 and 2, this cylindrical core 1 includes a plurality of partial cylindrical partial cores 2 connected in the circumferential direction C. Each partial core 2 includes a unit core 4 having one metal plate 3 (composed of one metal plate 3), and a plurality of unit cores 4 are stacked in the axial direction A while changing the posture so that the both end edges in the circumferential direction C are interchanged for each unit core 4. However, the positions of the unit cores 4 adjacent in the axial direction A in each partial core 2 are shifted in the circumferential direction C every time the both end edges of each unit core 4 are interchanged, as will be described later.

[0016] The unit cores 4 (metal plates 3) are laminated by crimp lamination, which involves lamination via crimps (dowels) 5. For crimp lamination, round dowel crimps or V-dowel crimps are used. Alternatively, lamination may be performed using other methods, such as adhesive lamination.

[0017] Each metal plate 3 is an arc-shaped metal plate having the same outer circumference shape, and both ends of the circumferential direction C when viewed in the axial direction A form two straight lines that form a predetermined angle as a central angle centered on the central axis of the cylindrical core 1. This central angle is, for example, the central angle obtained by dividing 360° by a natural number n. In this embodiment, the natural number n is set to 8. That is, in this embodiment, the cylindrical core 1 is formed by connecting eight partial cores 2.

[0018] Each adjacent subcore 2 has an overlapping portion 6 where each unit core 4 of one subcore 2 and each unit core 4 of the other subcore 2 overlap when viewed in the axial direction A. Each subcore 2 is closely connected to the others via its respective overlapping portion 6.

[0019] In other words, in adjacent partial cores 2, in one partial core 2, the position C in the circumferential direction of each unit core 4 is repeatedly displaced by a predetermined amount in one direction and the other direction each time the two ends are swapped as described above. In the other partial core 2, the position C in the circumferential direction of each unit core 4 is repeatedly displaced by the predetermined amount in the opposite direction to that of the first partial core 2 each time the two ends are swapped as described above. The predetermined amount is equal to the angle θ (see Figure 1) of the central angle occupied by the overlapping portion 6 between the adjacent partial cores 2.

[0020] Figure 3 shows how adjacent sub-cores 2 are connected to each other, as viewed from the central axis of the cylindrical core 1. In each overlapping portion 6 of adjacent sub-cores 2, as described above, the units are stacked in the axial direction A while changing their orientation so that the edges at both ends in the circumferential direction C are swapped for each unit core 4.

[0021] Therefore, the overlapping portions 6 of both partial cores 2 have a shape that allows them to fit together in the circumferential direction. Thus, adjacent partial cores 2 are connected to each other by the fitting together of their respective overlapping portions 6. The cylindrical core 1 is provided by housing a plurality of partial cores 2, which are connected in this manner in the circumferential direction C to form a cylindrical shape, within a cylindrical case 7, as shown in Figure 1.

[0022] According to this embodiment, each adjacent partial core 2 is closely connected to each other via the overlapping portion 6, and the ends of each adjacent metal plate 3 are electrically connected to each other, so a cylindrical core 1 that is substantially equivalent to a cylindrical core made of stacked annular metal plates can be provided. For this reason, when this cylindrical core 1 is applied to a slotless motor, it provides a magnetic reflection function to prevent magnetic flux leakage, prevents the generation of positive and negative magnetic forces by the cylindrical core 1, and suppresses the occurrence of cogging.

[0023] Furthermore, the cylindrical core 1 is formed by laminating arc-shaped metal plates 3 having the same outer circumference. Therefore, compared to the case where annular metal plates are laminated to form a cylindrical core, the steel plates used as the material for the metal plates 3 can be used efficiently to minimize wasted material, thereby reducing material costs.

[0024] Figure 4 shows a side view of the cylindrical core 1a according to the second embodiment of the present invention. The view of the cylindrical core 1a along the axial direction A is the same as in Figure 1. In the first embodiment, each partial core 2 is provided by stacking multiple, for example, 10, unit cores 4, each made of a single metal plate 3, whereas in this embodiment, as shown in Figure 4, each partial core 2a is provided by stacking multiple, for example, 3, unit cores 4a, each made by stacking several, for example, 4, metal plates 3.

[0025] Figure 5 shows how adjacent partial cores 2a are connected to each other. Similar to the first embodiment, in each partial core 2a, unit cores 4a are stacked in the axial direction A, changing their orientation so that the edges of both ends in the circumferential direction C are swapped for each unit core 4a. Each partial core 2a has an overlapping portion 6a where one unit core 4a and the other unit cores 4a overlap when viewed in the axial direction A.

[0026] Therefore, both partial cores 2a have a shape that allows them to fit together in the circumferential direction C at their respective overlapping portions 6a. Thus, as shown in Figure 4, each adjacent partial core 2a is closely connected to the others through the overlapping portions 6a, with their overlapping portions 6a fitting together. In other respects, it is the same as in the first embodiment.

[0027] Figure 6 shows a cylindrical core 1b according to the third embodiment of the present invention as viewed along the axial direction A (see Figure 1). As shown in Figure 6, the cylindrical core 1b comprises multiple partial cores 2b, similar to the partial core 2a in the second embodiment, connected in the circumferential direction C via an overlapping portion 6b.

[0028] Figure 7A shows how adjacent partial cores 2b are connected via the overlapping portion 6b. Figure 7B shows how adjacent partial cores 2b are connected via the overlapping portion 6b and become a single unit. In Figures 7A and 7B, each is shown as viewed from the central axis of the cylindrical core 1b.

[0029] As shown in Figure 7B, the overlapping portion 6b between each adjacent partial core 2b is provided with a through hole 8 extending from one surface F1 to the other surface F2 in the axial direction A of the cylindrical core 1b. Each adjacent partial core 2b is inserted into the through hole 8 and connected by a pin (thin round steel) 9 extending from the one surface F1 to the other surface F2.

[0030] As shown in Figures 7A and 7B, the through-holes 8 in the overlapping portions 6b of adjacent partial cores 2b are offset by a small central angle β in the circumferential direction C between the portions of the through-holes 8 in one partial core 2b and the portions of the through-holes 8 in the other partial core 2b. The direction of this offset is such that when a pin 9 is inserted into the through-hole 8, the close contact between adjacent partial cores 2b in the circumferential direction C is enhanced.

[0031] Specifically, as shown in Figure 7A, the central angle formed by the two end edges in the circumferential direction C of the overlapping portion 6b of adjacent partial cores 2b is defined as 2α, and the reference position Pd in ​​the overlapping portion 6b is defined as the position between the two end edges that makes a central angle α with the two end edges.

[0032] In one of the adjacent superimposed cores 2b, the through-hole 8 is located on the reference position Pd, while in the other superimposed core 6b, the through-hole 8 is located at a position shifted by a small central angle β from the reference position Pd towards the core 2b to which the other superimposed core 6b belongs. Note that the small central angle β is exaggerated and shown in a large size for ease of understanding.

[0033] In this case, by fitting adjacent partial cores 2b together in the overlapping portion 6b between them, a through hole 8 is formed with a partial offset of a central angle β, as shown in Figure 7B. By forcibly inserting a pin 9 into this through hole 8, both partial cores 2b are pressed together along the circumferential direction C with a force corresponding to the central angle β, thereby connecting the two partial cores 2b.

[0034] According to this embodiment, each adjacent partial core 2b is closely connected in the circumferential direction C by a pin 9 inserted into a through hole 8 in its overlapping portion 6b. Therefore, a cylindrical core 1b can be formed without the need to hold each partial core 2b in a case 7, as in the first and second embodiments. In other respects, it is the same as in the first and second embodiments.

[0035] Figure 8 shows a cylindrical core 1c according to the fourth embodiment of the present invention as viewed along the axial direction A (see Figure 1). Figure 9A shows a cross-section along the line IX-IX in Figure 8. As shown in Figures 8 and 9A, in the cylindrical core 1c of this embodiment, the pins 9 inserted into the through holes 8 of the overlapping portions 6c of each partial core 2c have crushed portions 10 on both end faces, which are formed by being pressed and crushed in the longitudinal direction of the pins 9. The other configurations are the same as in the third embodiment.

[0036] Figure 9B shows a method for forming the crushed portion 10. As shown in Figure 9B, the crushed portion 10 is formed by pressing the center of both end faces of the pin 9 inserted into the through hole 8 along the length of the pin 9 with a projection-type tool 11, thereby crushing it.

[0037] Even if the pin 9 is designed so that both ends do not protrude from the sides of the cylindrical core 1c, slight protrusion may still occur within the tolerance. In such cases, as shown in Figure 9C, by using a tip plane 12 with a larger diameter than the pin 9 as the tip of the projection-type tool 11, slight protrusion during the formation of the crushed portion 10 can be prevented by the tip plane 12.

[0038] According to this embodiment, the bonding force between the pin 9 and the through-hole 8 in the metal plate 3c at both ends is increased, thereby strengthening the fastening force between the partial cores 2c. Therefore, the cylindrical core 1c can be constructed without housing it in the case 7. Furthermore, by employing a flat tip 12 in the projection-type tool 11, the protrusion of the pin 9 can be prevented, thus improving workability in the next process.

[0039] Even in the embodiment shown in Figure 6, where the crushed portion 10 is not formed on the pin 9, there is still a possibility that both ends of the pin 9 may protrude slightly within tolerance from the surfaces on both sides of the cylindrical core 1b. In this case as well, as shown in Figure 9D, by using a tool 23 having a tip surface 22 composed of a single flat surface without protrusions, the tip surface 22 of the tool 23 can be used to press both end surfaces of the pin 9, which is inserted into the through hole 8 of the overlapping portion 6b, along the length direction of the pin 9, thereby preventing slight protrusion.

[0040] Figure 10 shows a cylindrical core 1d according to the fifth embodiment of the present invention as viewed along the axial direction A (see Figure 1). Figure 11 shows the shape of one end of a partial core 2d of the cylindrical core 1d in the circumferential direction. The cylindrical core 1d is characterized by the shape of the overlapping portion 6d between adjacent partial cores 2d.

[0041] In other words, in the overlapping portion 6d of the partial core 2d, as shown in Figures 10 and 11, each metal plate 3d forming the partial core 2d has a shape such that one end corresponding to the overlapping portion 6d and the other end can fit together in the circumferential direction C and be in close contact with each other.

[0042] Therefore, the adjacent ends of the unit cores 4d of the two adjacent subcores 2d form an overlapping portion 6d between the subcores 2d, and at the same time, the unit cores 4d overlap each other in the overlapping portion 6d when viewed in the radial direction R.

[0043] In other words, each metal plate 3d has one end that forms the overlapping portion 6d and the other end that is concave along the circumferential direction, and a convex shape that fits into it. Therefore, one end of a unit core 4d, which is made up of several stacked metal plates 3d, is concave along the circumferential direction and has a groove 13 that extends in the axial direction A.

[0044] Furthermore, the other end of the unit core 4d has a convex shape that protrudes along the circumferential direction and extends in the axial direction A, and has a protruding ridge 14 that fits tightly into the groove 13. In addition, through holes 8d and pins 9d, which have the same function as the through holes 8 and pins 9 in the third and fourth embodiments, are provided at the tips on both sides of the groove 13 and at the tips of the protruding ridges 14.

[0045] Furthermore, the tip and base ends of the groove 13 and the protrusion 14 may be provided with an outer corner chamfer 15d and a corresponding inner corner chamfer 24d along the axial direction A. This increases the contact area between the partial cores 2d in the circumferential direction C.

[0046] According to this embodiment, each partial core 2d overlaps in the radial direction R in addition to the axial direction A in the overlapping portion 6d, and makes close contact with each other over a wider contact area, thereby enabling better electrical conductivity between adjacent metal plates 3d in the circumferential direction C. Furthermore, the three pins 9 provided in the grooves 13 and protrusions 14 of the overlapping portion 6d between each partial core 2d allow for a stronger connection between the partial cores 2d.

[0047] Furthermore, if chamfered portions 15d are provided at the tips of the grooves 13 and ridges 14, the partial cores 2d can be easily connected to each other. Other aspects are the same as in the third and fourth embodiments. In this embodiment, each unit core 4d has one groove 13 and one ridge 14, but it is not limited to this and may have two or more of each.

[0048] Figure 12A shows a portion of the cylindrical core 1e according to the sixth embodiment, viewed along the axial direction A (see Figure 1). Figure 12B shows the shape of one end of the partial core 2e of the cylindrical core 1e. As shown in Figures 12A and 12B, the unit core 4e of each partial core 2e has two grooves 13e in one overlapping portion 6e and two protrusions 14e in the other overlapping portion 6e.

[0049] In this case as well, by providing a chamfered portion 15d at the outer corner and a corresponding chamfered portion 24d at the inner corner, the contact area between the partial cores 2e in the circumferential direction C can be increased. Other aspects are the same as in the fifth embodiment.

[0050] Figure 13 shows a cylindrical core 1f according to the seventh embodiment of the present invention as viewed along the axial direction A (see Figure 1). The cylindrical core 1f of this embodiment is housed in a cylindrical case 7. Similar to the case of the partial core 2d in Figure 11, the cylindrical core 1f has one overlapping portion 6f and the other overlapping portion 6f of each unit core 4f (see Figure 14A) that forms the partial core 2f, each having a concave groove 13 and a convex ridge 14 (see Figure 11).

[0051] Figures 14A to 14C show how adjacent partial cores 2f are connected using through holes 8f and pins 9f to form a cylindrical core 1f. Figures 14A to 14C show the cylindrical core 1f as viewed from its central axis.

[0052] As shown in Figures 14A to 14C, in this embodiment, through holes 8f and pins 9f with different diameters from the through holes 8d and pins 9d in Figures 10 and 11 are used as through holes and pins provided in the overlapping portion 6f to connect the partial cores 2f together.

[0053] In other words, as shown in Figure 14A, if the central angle occupied by the overlapping portion 6f of adjacent partial cores 2f is 2θ, then the central axis of the through-hole 8f portion of each overlapping portion 6f is located at a position that forms a central angle (θ-γ) with respect to the leading edge of each overlapping portion 6f.

[0054] Therefore, as shown in Figure 14B, when each partial core 2f is fitted together via the overlapping portion 6f to form through holes 8f aligned in the axial direction A, a gap of central angle 2γ is created between each partial core 2f.

[0055] Therefore, in this state, if a pin 9f having a diameter φN smaller than the diameter φM of the through hole 8f is inserted into the through hole 8f, the positional relationship between the partial cores 2f can be adjusted up to twice the central angle 2γ (=4γ) by setting the value of the central angle γ to a value equivalent to φM-φN.

[0056] For example, if the central angle 2γ is greater than (φM-φN), adjacent subcores 2f can be brought closer together with a gap of approximately 2γ-(φM-φN). If the central angle 2γ is less than or equal to (φM-φN), adjacent subcores 2f can be brought into close proximity, as shown in Figure 14C.

[0057] Therefore, by connecting multiple partial cores 2f via overlapping portions 6f, inserting pins 9f into through holes 8f in each overlapping portion 6f to form a cylindrical shape, and then bringing adjacent partial cores 2f close together or in close proximity as described above, a cylindrical core 1f with an outer diameter smaller than the inner diameter of the case 7 can be provisionally formed.

[0058] By placing this cylindrical core 1f inside the case 7 and separating adjacent partial cores 2f from each other, the diameter of the cylindrical core 1f can be increased, forming a cylindrical core 1f that fits snugly inside the case 7.

[0059] According to this embodiment, while it is generally difficult to manufacture a cylindrical core in which multiple partial cores are closely connected and fit inside the case 7, the diameter of the cylindrical core 1f can be adjusted to match the case 7, making it easy to manufacture a cylindrical core 1f that fits and is housed inside the case 7.

[0060] In this case, the circumferential edges C of adjacent partial cores 2f are separated, but even then, the overlapping portions 6f of both partial cores 2f overlap in the radial direction R and are in close contact, so the circumferentially adjacent metal plates 3f are in close contact radially and are electrically conductive to each other.

[0061] Therefore, according to this embodiment, by appropriately setting the diameter φM of the through hole 8f, the diameter φN of the pin 9, and the position of the central axis of the through hole 8f portion in the overlapping portion 6f, it is possible to realize a cylindrical core 1f that fits and is housed inside the case 7 while ensuring connection between the partial cores 2f and electrical conductivity between the metal plates 3f in the circumferential direction C.

[0062] Figure 15 is an explanatory diagram illustrating a partial core manufacturing apparatus used in the production of partial cores 2 and 2a according to the first and second embodiments described above. This partial core manufacturing apparatus includes a function (means) for feeding a steel sheet 16, which will be the material for the metal sheet 3, in the direction of travel D, and a function (means) for sequentially forming the metal sheet 3 by applying predetermined press processing to the steel sheet 16 being fed in the direction of travel D at each processing position P1 to P6.

[0063] The direction of travel D coincides with the direction along the radially extending centerline L1 of the arc shape 17, which includes the overlapping portions 6, 6a of the metal plates 3 in the steel plate 16. This arc shape 17 coincides with the shape of the partial cores 2, 2a as viewed along the axial direction A.

[0064] The partial core manufacturing apparatus has the function of forming a pilot hole 18 at processing position P1 to correct feed errors for subsequent processing positions P2 to P6. Furthermore, the partial core manufacturing apparatus has the function of forming the shapes of the overlapping portions 6, 6a on both sides of the metal plate 3 at processing positions P2 and P3.

[0065] In other words, at processing position P2, one of the overlapping portions 6, 6a of the metal plate 3 is punched out in the shape of the overlapping portion 6, 6a, while the other overlapping portion 6, 6a retains its original shape. Also, at processing position P3, one of the overlapping portions 6, 6a of the metal plate 3 retains its original shape, while the other overlapping portion 6, 6a is punched out in the shape of the overlapping portion 6, 6a.

[0066] In other words, at processing position P3, superimposed portions 6, 6a are formed in which the shapes of one superimposed portion 6, 6a and the other superimposed portion 6, 6a are swapped compared to the superimposed portions 6, 6a at processing position P2. The processing at processing position P2 and processing position P3 is selected and carried out according to the lamination position of the partial core 2, 2a of the metal plate 3 that is formed.

[0067] The partial core manufacturing apparatus has a function to provide a circular hole 19 at the processing position P4 for crimping and laminating the metal plate 3 to be formed. This function is performed when the metal plate 3 to be formed is to be placed at the first lamination position of the cylindrical cores 1, 1a.

[0068] The partial core manufacturing apparatus has the function of providing crimping 5 (dowels; round projections) for stacking the metal plates 3 to be formed at the same position as the round holes 19 on the metal plate 3 at the processing position P5. The partial core manufacturing apparatus has the function of cutting and separating the parts of the steel plate 16 other than the overlapping parts 6 and 6a at the processing position P6 to form the shape of the metal plate 3, and sequentially stacking the separated metal plates 3 according to the round holes 19 and crimping 5.

[0069] When manufacturing partial cores 2 and 2a using this partial core manufacturing apparatus, the steel plate 16 is fed in the direction of travel D (first step), and processing is sequentially performed at each processing position P1 to P6 on the portion of the steel plate 16 that will become the metal plate 3.

[0070] Specifically, first, a pilot hole 18 is formed at processing position P1. Then, at processing positions P2 and P3, overlapping portions 6 and 6a are formed on both sides of the metal plate 3. The formation of these overlapping portions 6 and 6a is carried out such that the radially extending center line of the arc shape 17 of the metal plate 3, which includes the overlapping portions 6 and 6a, coincides with a straight line L1 on the steel plate 16 that is parallel to the direction of travel D (second step).

[0071] In this second step, each time the formation of the overlapping portions 6, 6a of the metal plates 3 corresponding to the unit cores 4, 4a is completed, the shapes of the overlapping portions 6, 6a on both sides that are formed are changed (third step).

[0072] In other words, when the metal plate 3 to be formed is used for the partial core 2, the shape of the overlapping portions 6 on both sides alternates for each metal plate 3. Therefore, for each metal plate 3, punching out one overlapping portion 6 at processing position P2 and punching out the other overlapping portion 6 at processing position P3 are performed alternately.

[0073] On the other hand, if the metal plate 3 to be formed is to be used for a partial core 2a, and the unit core 4a of the partial core 2a is composed of four metal plates 3 as shown in Figure 5, then for every four metal plates 3, punching of one overlapping portion 6a at processing position P2 and the other overlapping portion 6a at processing position P3 are performed alternately.

[0074] Then, at processing positions P4 and P5, if the metal plate 3 to be formed is the first to be laminated in the partial cores 2 and 2a, a round hole 19 is formed, and if it is to be laminated in the second or subsequent stages, a crimp 5 is formed. Furthermore, at processing position P6, the metal plate 3 is punched out from the steel plate 16 (fourth step), and is sequentially laminated according to the round holes 19 and crimp 5 to form the partial cores 2 and 2a (fifth step).

[0075] Furthermore, the partial core manufacturing apparatus shown in Figure 15 and the method for manufacturing partial cores 2 and 2a using it can also be applied to the manufacturing of partial cores 2b (see Figure 6), partial core 2d (see Figure 10), partial core 2e (see Figure 12A), and partial core 2f (see Figure 14A) by making the overlapping portions 6 and 6a on both sides of the metal plate 3 formed at processing positions P2 and P3 correspond to the shapes of the respective overlapping portions 6b, 6d, 6e, and 6f.

[0076] Figures 16A to 16D illustrate the procedure (sixth step) for forming a cylindrical core by connecting partial cores, using the cylindrical core 1d in Figure 10 as an example. When forming a cylindrical core by connecting cylindrical cores 1d, first, as shown in Figure 16A, two partial cores 2d are fitted together at their overlapping portions 6d and connected. Next, two sets of these connected structures are similarly connected as shown in Figure 16B to form a structure with four connected partial cores 2d.

[0077] Then, as shown in Figure 16C, the ends of two sets of these four connected partial cores 2d are similarly connected to each other. This forms a cylindrical core 1d as shown in Figure 16D.

[0078] The same method can be used to form cylindrical cores other than cylindrical core 1d, such as cylindrical cores 1b, 1c, 1d, 1e, and 1f shown in Figures 6, 8, 10, 12A, and 13. In the case of cylindrical core 1b in Figure 6, adjacent cylindrical cores 1b can be easily fitted together by sliding them radially R (see Figure 11). The same applies to cylindrical core 1c in Figure 8.

[0079] It should be noted that the present invention is not limited to the embodiments described above. For example, the overlapping portions 6, 6a, and 6b of the partial cores 2, 2a, and 2b shown in Figures 3, 5, and 7A, respectively, may be provided with chamfered portions 20 extending along the radial direction R of the cylindrical cores 1, 1a, and 1b, as shown in Figures 17A to 17C.

[0080] The chamfered portion 20 is formed by chamfering the corners of the partial cores 2, 2a, and 2b that rub against each other when fitted together via the overlapping portions 6, 6a, and 6b, respectively. The chamfered portion 20 can be formed, for example, by crushing the corners of the metal plate 3 with a press die 21 in the press die when forming the metal plate 3 by pressing it, as shown in Figure 17D.

[0081] According to this, when the partial cores 2, 2a, and 2b are fitted together via the overlapping portions 6, 6a, and 6b, respectively, the chamfered portion 20 suppresses interference between the corners at which they pass each other, thus enabling the connection of the partial cores 2, 2a, and 2b to be carried out with good workability.

[0082] Furthermore, the technologies disclosed in each of the above embodiments can be applied to other embodiments to the extent applicable. For example, the embodiment in the third embodiment in which partial cores 2b are connected using pin 9 can also be applied when connecting partial cores 2 in the first embodiment or partial cores 2a in the second embodiment. [Explanation of symbols]

[0083] 1, 1a, 1b, 1c, 1d, 1e, 1f...Cylindrical core, 2, 2a, 2b, 2c, 2d, 2e, 2f...Partial core, 3, 3b, 3d, 3e, 3f...Metal plate, 4, 4a, 4b, 4d, 4e, 4f...Unit core, 5...Rivet, 6, 6a, 6b, 6d, 6e, 6f...Overlapping part, 7...Case, 8, 8d, 8f...Through hole, 9, 9d, 9f...Pin, 10...Crushing part, 11...Protruding tool, 12...Flat tip, 13, 13e...Concave groove, 14, 14e...Convex ridge, 15d, 24d...Chamfered part, 16...Steel plate, 17...Arc shape, 18...Pilot hole, 19...Round hole, 20...Chamfered part, 21...Press die, L1...Center line, P1~P6...Processing position.

Claims

1. A cylindrical core comprising multiple partially cylindrical subcores connected in the circumferential direction, Each subcore comprises a unit core, which consists of one or more stacked metal plates having the same outer circumference shape, with each unit core having a different orientation such that the circumferential edges of both ends are swapped, and these unit cores are stacked in the axial direction of the cylindrical core. The adjacent subcores have an overlapping portion where each unit core of one subcore and each unit core of the other subcore overlap in the axial direction. A cylindrical core characterized in that each sub-core is closely connected to one another via the overlapping portion.

2. When viewed in the axial direction of each unit core, the circumferential edges of both ends form two straight lines that make a predetermined angle as a central angle centered on the central axis of the cylindrical core. In the adjacent subcore, In the other part of the core, the circumferential position of each unit core is repeatedly displaced by a predetermined amount in one direction and the other direction each time the two end edges are swapped. In the other partial core, the circumferential position of each unit core is repeatedly displaced by a predetermined amount in the opposite direction to that of the other partial core, each time the two end edges are swapped. The cylindrical core according to claim 1, characterized in that the predetermined amount matches the angle of the central angle occupied by the overlapping portion between adjacent partial cores.

3. The metal plate has a shape at both ends that allows them to fit together tightly in the circumferential direction. The cylindrical core according to claim 1, characterized in that the adjacent ends of the unit cores of the mutually adjacent partial cores constitute the overlapping portion between the partial cores.

4. Each superimposed part is, A through hole in the cylindrical core extending from one surface to the other in the axial direction, A cylindrical core according to any one of claims 1 to 3, characterized by comprising pins inserted into each through hole and extending from one surface to the other surface.

5. The cylindrical core according to claim 4, characterized in that each through-hole is such that the portion of the through-hole located in one of the adjacent partial cores via the corresponding overlapping portion is offset by a small central angle in the circumferential direction with respect to the central axis of the cylindrical core, and the direction of this offset is such that the pin inserted into the through-hole enhances the circumferential contact between the partial cores.

6. The cylindrical core according to claim 4, characterized in that the pin has crushed portions formed at both end faces by being pressed in the longitudinal direction of the pin.

7. The cylindrical core according to claims 1 to 3, characterized in that each subcore has a chamfered portion for facilitating mutual connection via the overlapping portion.

8. The cylindrical core according to claims 1 to 3, characterized in that all of the metal plates have the same outer shape.

9. The cylindrical core according to claim 8, characterized in that the metal plate is an arc-shaped metal plate having both circumferential edges that form a central angle obtained by dividing 360° by a natural number n.

10. The cylindrical core is housed in a cylindrical case. The outer diameter of the cylindrical core matches the inner diameter of the case. The cylindrical core according to claim 4, characterized in that the through hole has a diameter larger than the diameter of the pin inserted into the through hole.

11. A method for manufacturing a cylindrical core comprising a plurality of partially cylindrical partial cores connected in the circumferential direction, wherein each partial core comprises a unit core having one or more metal plates having the same outer circumference shape stacked together, and the orientation of each unit core is changed so that the circumferential edges of both ends of the cylindrical core are swapped, and the adjacent partial cores have an overlapping portion where each unit core of one partial core and each unit core of the other partial core overlap in the axial direction, and the partial cores are closely connected to each other via the overlapping portion, The first step involves advancing a steel sheet, which will be the material for the metal sheet, so that the portion that will become the metal sheet sequentially passes through predetermined processing positions. A second step is to form the overlapping portions on both sides of the portion that will become the metal plate at the processing position, In the second step, each time the formation of the overlapping portion of the metal plate portion is completed for the number of metal plate portions constituting the unit core, a third step is taken in which the shape of the overlapping portion on both sides to be formed is alternated. A fourth step involves separating the portion of the metal plate formed by the overlapping portions on both sides in the second step from the steel plate and sequentially obtaining the metal plate, A fifth step involves sequentially stacking the metal plates obtained in the fourth step to form the partial core, A method for manufacturing a cylindrical core, comprising a sixth step of connecting the partial cores obtained in the fifth step in the circumferential direction via the overlapping portion to form a cylindrical shape.

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