Caulking device for motor core

Abstract

To provide a caulking device for a motor core capable of suppressing enlargement the a physical constitution of the caulking device.SOLUTION: A caulking device 40 comprises a stationary die 41 which is in contact with one end face 10a of a laminate 10A, and a movable die 43 which is provided so as to approach and separate from the stationary die 41 and comes into contact with the other end face 10b of the laminate 10A, thereby applying a load to the laminate 10A. A plurality of protrusions 45 protruding toward respective caulking parts are provided on a bottom face 44a of the movable die 43, the bottom face 44a being opposed to the other end face 10b in the plate thickness direction.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a crimping device for a motor core. [Background technology]

[0002] Patent Document 1 describes a method for manufacturing a stator core. This manufacturing method includes a lamination process in which a laminate is formed by stacking a plurality of core plates (hereinafter, core pieces), a heat treatment process in which the laminate is heat-treated, and a pressurization process in which the laminate is pressed in the plate thickness direction after the heat treatment process.

[0003] In the lamination process, the iron core pieces are connected to each other by crimping dowels provided on adjacent iron core pieces. In the heat treatment process, an oxide film is formed on the surfaces of the multiple core pieces.

[0004] In the pressing step, the laminate fixed to the fixture is pressed by a pressing device. Specifically, a load is applied to the laminate by the pressing device, so that the dowels of the adjacent core pieces are crimped again. The pressing device has an annular upper plate that contacts one surface of the laminate.

[0005] In this manufacturing method, the heat treatment process reduces iron loss in the stator core, while adjacent core pieces are fixed to each other by an oxide film with a gap between them in the plate thickness direction. The pressurizing process releases the adhesion between the core pieces and compresses the gaps between the core pieces, thereby keeping the stack thickness of the laminate within a predetermined tolerance range. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent Publication No. 2021-27737 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in a conventional crimping device including the above-mentioned pressure device, the upper plate is in surface contact with the entire surface of one side of the laminate. Therefore, the load applied to the laminate by the crimping device is dispersed by the upper plate. For this reason, there is a problem that the size of the crimping device tends to become large when applying a load sufficient to compress the gaps between the multiple core pieces. [Means for solving the problem]

[0008] A motor core crimping device for solving the above-mentioned problems is a motor core crimping device that crimps the dowels of adjacent core pieces by applying a load in the thickness direction to a laminate formed by stacking a number of core pieces in the thickness direction of the core pieces, each of the core pieces being provided with a number of dowels that bulge out to one side in the thickness direction, the motor core crimping device comprising: a fixed mold that abuts one end face of the laminate; and a movable mold that is capable of approaching and moving away from the fixed mold and applies a load to the laminate by abutting the other end face opposite the one end face, wherein when a location of the laminate where the dowels are lined up in the thickness direction is defined as a crimping portion, a surface of the movable mold that faces the other end face in the thickness direction is provided with a number of protrusions that protrude toward each of the multiple crimping portions.

[0009] According to this configuration, when the movable die is brought close to the fixed die to apply a load to the laminate, the multiple protrusions first come into contact with the other end surface of the laminate. Then, the load applied to the movable die acts on the multiple crimping portions of the laminate via the multiple protrusions. This causes the dowels of the core pieces adjacent to each other in the plate thickness direction to be crimped together.

[0010] Here, the load acts on each crimping portion via the tip surface of each protrusion. Therefore, the surface pressure of the movable die is larger than when the movable die applies a load to the laminate in surface contact with the entire other end surface of the laminate. As a result, it is easier to obtain sufficient surface pressure for crimping the dowels together while reducing the load applied to the movable die compared to the conventional crimping device equipped with the movable die described above.

[0011] Therefore, it is possible to prevent the size of the crimping device from becoming larger due to an increase in the load applied to the movable die. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view of a stator core according to one embodiment. [Diagram 2] FIG. 2 is an enlarged cross-sectional view showing a part of the cross section taken along line 2-2 of FIG. [Diagram 3] FIG. 3 is a flowchart showing a manufacturing procedure of the stator core of FIG. [Figure 4] FIG. 4 is a cross-sectional view showing the crimping step. [Diagram 5] FIG. 5 is a cross-sectional view showing the annealing step. [Figure 6] FIG. 6 is a cross-sectional view showing a crimping device used in the re-crimping step. [Figure 7] FIG. 7 is a bottom view showing a movable die of the crimping device of FIG. [Figure 8] FIG. 8 corresponds to FIG. 6 and is a cross-sectional view showing the re-crimping step. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] An embodiment of a motor core crimping device will be described below with reference to Figures 1 to 8. In this embodiment, the present invention is embodied as a crimping device for a stator core. <Stator core 10> As shown in Fig. 1, the stator core 10 is substantially cylindrical and has a central hole 11. The stator core 10 is formed of a laminate 10A in which a plurality of core pieces 20 made of electromagnetic steel sheets are laminated in the sheet thickness direction of the core pieces.

[0014] In the following description, the radial direction of stator core 10 is simply referred to as the radial direction, and the circumferential direction of stator core 10 is simply referred to as the circumferential direction. The stator core 10 has an annular yoke 12 and a plurality of teeth 13 extending radially inward from the yoke 12 and formed at intervals from one another in the circumferential direction.

[0015] Between the teeth 13 adjacent to each other in the circumferential direction, a slot 14 is formed which opens radially inward and extends radially. The outer peripheral surface of the stator core 10 is provided with a plurality of fixing portions 15 for fixing the stator core 10 to a case of a rotating electrical machine (not shown). The fixing portions 15 protrude radially outward from the yoke 12 and are provided at intervals from one another in the circumferential direction. The fixing portions 15 are formed with mounting holes 15a penetrating in the plate thickness direction. In the stator core 10 of this embodiment, one mounting hole 15a is provided for each fixing portion 15. The stator core 10 and the case are fixed with bolts (not shown) inserted into the respective mounting holes 15a.

[0016] <Core piece 20> As shown in Figures 1 and 2, the multiple core pieces 20 have multiple first core pieces 21 stacked continuously and one second core piece 23 stacked on one side of the multiple first core pieces 21 (the upper side in the vertical direction in Figures 1 and 2).

[0017] The multiple first core pieces 21 have the same configuration. For this reason, one first core piece 21 will be described here, and detailed descriptions of the remaining first core pieces 21 will be omitted.

[0018] The first core piece 21 has a dowel 22 that bulges in the plate thickness direction toward the second core piece 23. The dowels 22 are formed in a portion of the first core piece 21 that corresponds to the yoke 12, and a plurality of dowels 22 are provided at intervals from each other in the circumferential direction (see FIG. 1).

[0019] The dowel 22 has a convex portion 22a protruding from one side (upper side in Figure 2) of the first core piece 21, and a concave portion 22b provided at a position corresponding to the convex portion 22a on the other side (lower side in Figure 2) of the first core piece 21.

[0020] The first core pieces 21 adjacent to each other in the plate thickness direction are joined by crimping the dowels 22. In detail, the first core pieces 21 adjacent to each other in the plate thickness direction are joined to each other by fitting the protruding portion 22a of the dowel 22 of one first core piece 21 into the recessed portion 22b of the dowel 22 of the other first core piece 21 and crimping them.

[0021] The second core piece 23 has a hole 24 into which the protruding portion 22a of the dowel 22 of the first core piece 21 adjacent to the second core piece 23 fits. The holes 24 are formed in a portion of the second core piece 23 corresponding to the yoke 12, and a plurality of holes 24 are provided at intervals from each other in the circumferential direction (see FIG. 1). The holes 24 are provided at positions overlapping with the dowels 22 in the plate thickness direction. The holes 24 are rectangular and extend in the circumferential direction.

[0022] The crimped portion 16 is formed by a plurality of dowels 22 overlapping in the plate thickness direction and holes 24 . <Manufacturing process of stator core 10> Next, a manufacturing procedure for the stator core 10 will be described with reference to FIGS.

[0023] As shown in FIG. 3, the manufacturing process of the stator core 10 includes a press lamination step, a crimping step, an annealing step, and a re-crimping step. The press lamination process includes a dowel forming process and a hole forming process.

[0024] The dowel forming process and the hole forming process are both performed before the punching process in which the core pieces 20 are punched out from the workpiece. In the dowel forming step, the workpiece is pressed by a press device to form dowels 22 in the portion of the workpiece that will become first core piece 21.

[0025] In the hole forming step, the workpiece is pressed by a press device to form holes 24 in the portion of the workpiece that will become second core piece 23. In the press lamination step, a plurality of first core pieces 21 are laminated on the second core piece 23 to form a laminate 10A in which a plurality of core pieces 20 are laminated.

[0026] <Crimping process> As shown in FIG. 4, in the crimping process, first, one end surface 10a of the laminate 10A is placed on the upper surface 31a of the lower die 31. Then, the upper die 32 is placed on the other end surface 10b opposite to the one end surface 10a. Then, the upper die 32 is pressed toward the lower die 31 to press the laminate 10A in the plate thickness direction. At this time, a load of a first predetermined value P1 is applied to the laminate 10A by the upper die 32 and the lower die 31. The first predetermined value P1 is, for example, 30t. As a result, the dowels 22 adjacent to each other in the plate thickness direction are crimped to each other, and the dowels 22 adjacent to the holes 24 in the plate thickness direction are fitted into the holes 24.

[0027] When the pressure applied by the upper die 32 and the lower die 31 is released, small gaps are formed between the core pieces 20 due to spring back of the core pieces 20. This causes the lamination thickness of the laminate 10A to increase compared to immediately after the crimping process.

[0028] <Annealing process> As shown in FIG. 5, in the annealing step, the laminate 10A is transferred into a heating furnace 33, whereby the laminate 10A is annealed.

[0029] High-temperature atmospheric gas is filled inside the heating furnace 33. The atmospheric gas is, for example, DX gas with a low dew point that is generated by incompletely combusting city gas and performing a dehumidification process.

[0030] By the annealing process, an oxide film is formed on the surfaces of the plurality of iron core pieces 20, and adjacent iron core pieces 20 are fixed to each other by the oxide film with the above-mentioned gap therebetween. <Re-crimping process> In the re-crimping step, a crimping device 40 shown in Figs. 6 and 7 is used.

[0031] First, the crimping device 40 will be described. As shown in FIG. 6, the crimping device 40 includes a fixed die 41 and a movable die 43 that is movable toward and away from the fixed die 41.

[0032] The fixed mold 41 has a square shape in a plan view, and is placed on a table (not shown). On an upper surface 42 of the fixed mold 41, one end surface 10a of the laminate 10A is placed. 6 and 7, the movable die 43 has a flat plate portion 44 that is square in plan view and faces the other end surface 10b in the plate thickness direction, and a protruding portion 45 that protrudes from a lower surface 44a of the flat plate portion 44. In FIG. 7, the outline of the laminate 10A that faces the lower surface 44a of the movable die 43 is indicated by a two-dot chain line.

[0033] The protrusions 45 are provided at intervals from one another in the circumferential direction, and protrude from the lower surface 44a toward each of the crimping portions 16. Note that the crimping portions 16 are not shown in FIG.

[0034] A tip surface 45a of each protrusion 45 has a circular shape in a plan view. The tip surface 45a covers the entire facing crimping portion 16 (see FIG. 7). As shown in FIG. 6, the flat plate portion 44 has a receiving portion 46 at the center of the upper surface 44b thereof, the receiving portion 46 protruding upward.

[0035] A concave spherical lower support portion 46a is provided on the upper surface of the receiving portion 46 to support the ball 47 in a rollable manner. Above the receiving portion 46, there is provided a mounting portion 48 having an upper support portion 48a having a concave surface for supporting the ball 47 so that the ball 47 can roll.

[0036] The mounting portion 48 is attached to a load application device (not shown). The receiving portion 46 and the mounting portion 48 are connected by a connecting portion (not shown). The movable die 43 is lowered via the attachment parts 48 and the spheres 47 by a load application device (not shown), whereby a load is applied to the laminate 10A by the movable die 43 and the fixed die 41.

[0037] 8, in the re-crimping process, a load of a second predetermined value P2 is applied to the laminate 10A in the plate thickness direction by a crimping device 40, thereby crimping the dowels 22 of adjacent core pieces 20. The second predetermined value P2 is, for example, not less than 1t and not more than 2t.

[0038] Next, the operation of this embodiment will be described. 8, when the movable die 43 is brought close to the fixed die 41 in order to apply a load to the laminate 10A, first the multiple protrusions 45 come into contact with the other end surface 10b of the laminate 10A. Then, the load applied to the movable die 43 acts on the multiple crimping portions 16 of the laminate 10A via the multiple protrusions 45. As a result, the dowels 22 of the core pieces 20 adjacent to each other in the plate thickness direction are crimped together. As a result, the gaps between the multiple core pieces 20 are compressed.

[0039] Next, the effects of this embodiment will be described. (1) The crimping device 40 includes a fixed die 41 that contacts one end surface 10a of the laminate 10A, and a movable die 43 that is movable toward and away from the fixed die 41 and applies a load to the laminate 10A by contacting the other end surface 10b of the laminate 10A. A lower surface 44a of the movable die 43 that faces the other end surface 10b in the plate thickness direction is provided with a plurality of protrusions 45 that protrude toward each of the plurality of crimping portions 16.

[0040] This configuration provides the above-mentioned effects. Here, the load acts on each crimping portion 16 via the tip surface 45a of each protrusion 45. Therefore, the surface pressure of the movable die 43 is larger than when the load is applied to the laminate 10A with the movable die in surface contact over the entire other end surface 10b of the laminate 10A. This makes it easier to obtain sufficient surface pressure for crimping the dowels 22 together while reducing the load applied to the movable die 43 compared to the crimping device equipped with the conventional movable die described above.

[0041] Therefore, the size of the crimping device 40 can be prevented from increasing due to an increase in the load applied to the movable die 43. (2) The tip surface 45a of the protruding portion 45 covers the entire crimping portion 16 in the plate thickness direction.

[0042] With this configuration, a load can be suitably applied to the multiple crimped portions 16 . <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.

[0043] The shape of the tip surface 45a of the protrusion 45 is not limited to the circular shape in plan view exemplified in this embodiment, and may be changed as appropriate. For example, the shape of the tip surface 45a may be an ellipse or a rectangle in plan view.

[0044] The protrusion 45 is not limited to the protrusion having the tip surface 45a covering the entire crimping portion 16 in the thickness direction as illustrated in this embodiment, but the tip surface 45a may cover only a portion of the crimping portion 16 in the thickness direction.

[0045] The movable die according to the present invention can also be applied to the upper die 32 in the crimping process. According to this configuration, the same effects as those described in (1) and (2) above can be obtained in the crimping process as well.

[0046] The present invention can also be embodied as a crimping device used in a manufacturing method of a rotor core. [Explanation of symbols]

[0047] 10…Stator core 10A…Laminate 10a...One end surface 10b...Other end surface 11...Center hole 12…York 13. Teeth 14. Slot 15...Fixed part 15a…Mounting hole 16… Crimping part 20…Iron core piece 21…First core piece 22…Dabo 22a…Convex part 22b…recess 23…Second core piece 24...hole 31…Lower mold 31a…Top surface 32…Upper mold 33…Heating furnace 40…Crimping device 41…Fixed type 42…Top surface 43…Movable type 44...Flat plate part 44a…Bottom surface 44b…Top surface 45...Protruding part 45a…Tip surface 46…Receiving part 46a…Lower support part 47…Sphere 48…Mounting part 48a...Upper support part P1...first predetermined value P2…Second predetermined value

Claims

1. A motor core crimping device is provided with a laminate formed by stacking a plurality of core pieces in a plate thickness direction of the core pieces, each of the core pieces being provided with a plurality of dowels that bulge out to one side in the plate thickness direction, the device crimping the dowels of adjacent core pieces by applying a load in the plate thickness direction to the laminate, A fixed mold abutting on one end surface of the laminate; a movable die that is provided so as to be capable of approaching and moving away from the fixed die and that applies a load to the laminate by contacting the other end face of the laminate opposite to the one end face, When a portion where a plurality of the dowels overlap in the plate thickness direction of the laminate is defined as a crimping portion, a surface of the movable die facing the other end surface in the plate thickness direction is provided with a plurality of protruding portions protruding toward the respective crimping portions; Motor core crimping device.

2. The tip surface of the protrusion covers the entire crimping portion in the plate thickness direction.

2. The motor core crimping device according to claim 1.

Images