Manufacturing method of laminated steel sheet

Abstract

To provide a manufacturing method of a laminated steel sheet that can reduce the width of the bridge of the laminated steel sheet of a rotor core while ensuring strength.SOLUTION: A manufacturing method of a laminated steel sheet according to the present disclosure for forming a laminated steel sheet of a rotor core from an electromagnetic steel sheet includes a thickening step of thickening a bridge portion in the width direction by pressing against the bridge portion of the electromagnetic steel sheet from above and below, and a punching step of punching a bridge of the laminated steel sheet from the bridge portion of the electromagnetic steel sheet. The thickening step includes a first thickening step of pressing both widthwise ends of the bridge portion from above and below, and a second thickening step of pressing both widthwise ends of the bridge portion thickened by the first thickening step from above and below. In the punching step, a bridge of laminated steel sheet is punched from the bridge portion thickened by the second thickening step.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a laminated steel plate.

Background Art

[0002] Patent Document 1 discloses a rotor core structure in which the strength of the bridges of the laminated steel plates of the rotor core is improved.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, in order to improve the efficiency of the motor, it is required to ensure the strength while reducing the width of the bridges of the laminated steel plates of the rotor core.

[0005] The present disclosure has been made in view of such circumstances, and provides a method for manufacturing a laminated steel plate capable of ensuring strength while reducing the width of the bridges of the laminated steel plates of the rotor core.

Means for Solving the Problems

[0006] The method for manufacturing a laminated steel plate according to the present disclosure is a method for manufacturing a laminated steel plate of a rotor core from an electromagnetic steel plate, a thickening step of thickening the width direction of the bridge portion by pressing the bridge portion of the electromagnetic steel plate from above and below, a punching step of punching the bridge of the laminated steel plate from the bridge portion of the electromagnetic steel plate, and includes in the thickening step, a first thickening step of pressing both end portions in the width direction of the bridge portion from above and below, A second thickening step of pressing both end portions in the width direction of the bridge portion thickened by the first thickening step from above and below, In the punching step, The bridge of the laminated steel plate is punched from the bridge portion thickened by the second thickening step.

[0007] In the method for manufacturing a rotor core according to the present disclosure, both end portions in the width direction of the bridge portion are pressed from above and below, and further, both end portions in the width direction of the thickened bridge portion are pressed from above and below. With such a configuration, since the thickened bridge portion can be punched, a laminated steel plate for a rotor core can be manufactured while reducing the width of the bridge and ensuring strength.

Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a method for manufacturing a laminated steel plate capable of ensuring strength while reducing the width of the bridge of the laminated steel plate for a rotor core.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same or corresponding elements are denoted by the same reference numerals, and redundant descriptions are omitted as necessary for clarity of explanation. Also, some reference numerals are omitted so that the drawings do not become complicated. Of course, the right-handed xyz orthogonal coordinates shown in the drawings are for convenience in explaining the positional relationship of the components. Usually, the positive direction of the z-axis is vertically upward, and the xy plane is a horizontal plane.

[0011] (Embodiment 1) <Method for manufacturing a laminated steel plate> Hereinafter, Embodiment 1 of the present disclosure will be described with reference to the drawings. FIG. 1 is a flowchart illustrating a method for manufacturing a laminated steel plate according to Embodiment 1. FIG. 2 is a schematic diagram showing the method for manufacturing a laminated steel plate according to Embodiment 1. In FIG. 2, the states of step ST1, step ST2, and step ST5 in FIG. 1 are shown. The method for manufacturing a laminated steel plate according to Embodiment 1 forms a laminated steel plate for a rotor core from an electromagnetic steel plate. The rotor core is formed by laminating laminated steel plates. That is, the laminated steel plate can also be said to be a laminated plate of the rotor core.

[0012] First, as shown in FIG. 1, by pressing both end portions in the width direction of the bridge portion of the electromagnetic steel plate from the vertical direction, the width direction of the bridge portion is thickened (step ST1). Step ST1 is referred to as the first thickening step.

[0013] Referring to FIG. 2, step ST1 (the first thickening step) will be described. As shown in FIG. 2, in step ST1, one end portion R1 in the width direction of the bridge portion B1 of the electromagnetic steel plate is pressed from the vertical direction by a punch P1. Also, as shown in FIG. 2, in step ST1, the other end portion R2 in the width direction of the bridge portion B1 of the electromagnetic steel plate is pressed from the vertical direction by a punch P2. As a result, the bridge portion B1 of the electromagnetic steel plate between the punches P1 and P2 bulges and thickens due to the leakage of material from both end portions R1 and R2.

[0014] Next, as shown in FIG. 1, both end portions in the width direction of the bridge portion thickened by the first thickening step are pressed from the vertical direction (step ST2). Step ST2 is referred to as the second thickening step. The first thickening step and the second thickening step are collectively referred to as the thickening step.

[0015] Referring to FIG. 2, the step ST2 (second thickening step) will be described. As shown in FIG. 2, in step ST2, one end R3 in the width direction of the bridge portion B1 of the electromagnetic steel sheet is pressed from above and below by the punch P3. Also, as shown in FIG. 2, in step ST2, the other end R4 in the width direction of the bridge portion B1 of the electromagnetic steel sheet is pressed from above and below by the punch P4. The ends R3 and R4 are both ends in the width direction of the bridge portion thickened by the first thickening step.

[0016] As a result, the bridge portion B1 of the electromagnetic steel sheet between the punches P3 and P4 has meat leaking from both ends R3 and R4 and thickens. That is, the bridge portion B1 of the electromagnetic steel sheet thickens step by step toward the central portion by the first thickening step and the second thickening step. The portion of the bridge portion B1 of the electromagnetic steel sheet thickened by the first thickening step and the second thickening step is referred to as the thickened portion V1.

[0017] Next, as shown in FIG. 1, one surface of the bridge portion of the electromagnetic steel sheet is pressed to project the bridge portion from the electromagnetic steel sheet (step ST3). Step ST3 is referred to as the bending step.

[0018] Next, as shown in FIG. 1, both surfaces of the bridge portion of the electromagnetic steel sheet are constrained to crush the bridge portion to its original thickness (step ST4). Step ST4 is referred to as the crushing step.

[0019] Next, as shown in FIG. 1, the bridge of the laminated steel sheet is punched out from the bridge portion of the electromagnetic steel sheet (step ST5). Step ST5 is referred to as the punching step.

[0020] Referring to FIG. 2, step ST5 will be described. Step ST5 shown in FIG. 2 shows a state in which the bridge B2 of the laminated steel sheet is punched out from the bridge portion B1 of the electromagnetic steel sheet. As shown in FIG. 2, the thickening portion V1 is gripped by the pad PA1 and the die D1 from the vertical direction. Then, as shown in FIG. 2, the end portions R1 to R4 pressed by the first thickening step and the second thickening step are pressed by the punches P5 and P6. As a result, the end portions R1 to R4 are detached from the electromagnetic steel sheet, and the thickening portion V1 becomes the bridge B2 of the laminated steel sheet. That is, in step ST5, the bridge B2 of the laminated steel sheet is punched out from the bridge portion B1 of the electromagnetic steel sheet 10.

[0021] The manufacturing method of the laminated steel sheet according to Embodiment 1 can form the bridge of the laminated steel sheet of the rotor core by steps ST1 to ST5. Further, the manufacturing method of the laminated steel sheet according to Embodiment 1 can work-hardening the bridge of the laminated steel sheet of the rotor core by steps ST1 to ST5.

[0022] Note that the above-described punches P1 to P6 have R-shaped ends in order to prevent cracking of the object to be pressed. Further, the punches P1 to P6 may be DLC (Diamond-Like Carbon) coated. Thereby, the friction coefficient of the punches P1 to P6 can be reduced. Therefore, the resistance of the punches P1 to P6 to cause the meat to leak from the end portions R1 to R4 and move to the thickening portion V1 is reduced, and the pressing load of P1 to P6 can be reduced.

[0023] <Manufacturing method of laminated steel sheet according to Comparative Example> Subsequently, the manufacturing method of the laminated steel sheet according to the comparative example will be described. In the manufacturing method according to the comparative example, among steps ST1 to ST5 shown in FIG. 1, the process corresponding to step ST2 is omitted. That is, the processes corresponding to steps ST1, ST3 to ST5 are performed to manufacture the bridge of the laminated steel sheet. Referring to FIG. 3, the punching process (the process corresponding to step ST5) of the manufacturing method of the rotor core according to the comparative example will be described.

[0024] FIG. 3 is a schematic view showing a punching process of a method for manufacturing a laminated steel sheet according to a comparative example. As shown in FIG. 3, the thickened portion V2 has an uneven shape. Therefore, as shown in FIG. 3, the pad PA2 and the die D2 require a width L1 of a space SP1 for accommodating flash when punching the thickened portion V2. Further, as shown in FIG. 3, the pad PA2 and the die D2 require a width L2 for pressing both sides of the thickened portion V2 in order to punch the thickened portion V2. That is, as shown in FIG. 3, the pad PA2 and the die D2 require a width L3 including the width L1 and the width L2.

[0025] Here, in the method for manufacturing a rotor core according to the comparative example, if the width of the thickened portion V2 is increased and the thickened portion V2 is punched, the width L1 of the space SP1 for accommodating flash when punching the thickened portion V2 becomes unnecessary. Thereby, the widths of the pad PA2 and the die D2 can be reduced. However, in the method for manufacturing a rotor core according to the comparative example, since the process corresponding to step ST2 shown in FIG. 1 is omitted, when the width of the thickened portion V2 is increased, the strength of the bridge of the laminated steel sheet decreases.

[0026] On the other hand, in the method for manufacturing a laminated steel sheet according to Embodiment 1, since the second thickening process is performed, as shown in step ST5 of FIG. 2, the pad PA1 and the die D1 can secure a width L4 smaller than the width L3 and perform punching. Further, in the method for manufacturing a laminated steel sheet according to Embodiment 1, since the second thickening process is performed, the thickened portion V1 shown in FIG. 2 is thicker than the thickened portion V2 shown in FIG. 3. Thereby, in the method for manufacturing a rotor core according to Embodiment 1, it is possible to secure the strength of the bridge of the laminated steel sheet while reducing the width of the bridge of the laminated steel sheet.

[0027] As described above, in the method for manufacturing a rotor core according to Embodiment 1, both end portions in the width direction of the bridge portion are pressed from the vertical direction, and further, both end portions in the width direction of the thickened bridge portion are pressed from the vertical direction. With such a configuration, since the thickened bridge portion can be punched, it is possible to manufacture a laminated steel sheet with a reduced bridge width and ensured strength.

[0028] Note that the present invention is not limited to the above-described embodiments, and can be appropriately modified without departing from the gist thereof. That is, the above description has been appropriately omitted and simplified for the sake of clarity of explanation, and those skilled in the art can easily change, add, and convert each element of the embodiment within the scope of the present invention.

Explanation of Reference Numerals

[0029] 10 Electromagnetic steel sheet B1 Bridge portion B2 Bridge D1, D2 Dies L1, L2, L3, L4 Widths P1, P2, P3, P4, P5, P6 Punches PA1, PA2 Pads R1, R2, R3, R4 Ends SP1 Space V1, V2 Build-up portions

Claims

【Claim 1】 A method for manufacturing a laminated steel sheet that forms a laminated steel sheet of a rotor core from an electromagnetic steel sheet, comprising: a thickening step of thickening the width direction of the bridge portion of the electromagnetic steel sheet by pressing from above and below against the bridge portion of the electromagnetic steel sheet; a punching step of punching out the bridge of the laminated steel sheet from the bridge portion of the electromagnetic steel sheet; and in the thickening step, a first thickening step of pressing both end portions in the width direction of the bridge portion from above and below; a second thickening step of pressing both end portions in the width direction of the bridge portion thickened by the first thickening step from above and below; in the punching step, punching out the bridge of the laminated steel sheet from the bridge portion thickened by the second thickening step. A method for manufacturing a laminated steel sheet.

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