Method for manufacturing laminated steel plate

Abstract

To provide a method for manufacturing a laminated steel plate capable of reinforcing an outer peripheral bridge of the laminated steel plate of a rotor core while securing torque of a motor.SOLUTION: A method for manufacturing a laminated steel plate of a rotor core from an electromagnetic steel plate includes: a thickening step of thickening a bridge portion of the electromagnetic steel plate in a width direction by pressing the bridge portion from a vertical direction; a bending step of pressing one surface of the bridge portion to cause the bridge portion to protrude from the electromagnetic steel plate; and a step of restraining both surfaces of the bridge portion to crush the bridge portion to an original thickness. In the thickening step, while one end portion of the bridge portion in the width direction, which is the end portion on an outer circumferential side of the rotor core, is gripped from both sides, the other end portion of the bridge portion in the width direction, which is the end portion on an inner circumferential side of the rotor core, is pressed from the vertical direction.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a rotor core structure in which the strength of the bridges of a laminated steel sheet of a 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] In the upper part of FIG. 3, a conceptual diagram showing a state of thickening the bridge portion of an electromagnetic steel sheet is illustrated. By pressing the bridge portion of the electromagnetic steel sheet 10 from above and below by the pressing portion S1 and the pressing portion S2, the width direction of the bridge portion is thickened. The pressing portion S2 includes a portion that will later correspond to the laminated steel sheet of the stator core. When the pressing portion S2 is pressed, not only does the thickness of the stator decrease, but the magnetic permeability also decreases, resulting in a decrease in magnetic flux and a reduction in the torque of the motor.

[0005] The present disclosure has been made in view of such circumstances, and provides a method for manufacturing a laminated steel sheet capable of strengthening the outer peripheral bridges of the laminated steel sheet of a rotor core while ensuring the torque of the motor.

Means for Solving the Problems

[0006] The method for manufacturing a laminated steel sheet according to the present disclosure is a method for manufacturing a laminated steel sheet of a rotor core from an electromagnetic steel sheet, a thickening step of thickening the width direction of the bridge portion by pressing the bridge portion of the electromagnetic steel sheet from above and below, A bending step of pressing one surface of the bridge portion to project the bridge portion from the electromagnetic steel sheet, A step of restraining both surfaces of the bridge portion and crushing the bridge portion to its original thickness, comprising: In the thickening step, While gripping one end in the width direction of the bridge portion, which is the end on the outer peripheral side of the rotor core, from both sides, the other end in the width direction of the bridge portion, which is the end on the inner peripheral side of the rotor core, is pressed from above and below.

[0007] In the method for manufacturing a laminated steel sheet according to the present disclosure, while gripping one end in the width direction of the bridge portion, which is the end on the outer peripheral side of the rotor core, from both sides, the other end in the width direction of the bridge portion, which is the end on the inner peripheral side of the rotor core, is pressed from above and below. With such a configuration, it is possible to manufacture a laminated steel sheet with an enhanced outer peripheral bridge of the rotor core while ensuring the torque of the motor.

Advantages of the Invention

[0008] According to the present disclosure, it is possible to provide a method for manufacturing a laminated steel sheet capable of strengthening the outer peripheral bridge of the laminated steel sheet of the rotor core while ensuring the torque of the motor.

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) ><Manufacturing method of laminated steel sheet> Hereinafter, Embodiment 1 of the present disclosure will be described with reference to the drawings. FIG. 1 is a flowchart illustrating a manufacturing method of a laminated steel sheet according to Embodiment 1. FIG. 2 is a schematic diagram showing the manufacturing method of the laminated steel sheet according to Embodiment 1. FIG. 2 shows the state of step ST1 in FIG. 1. The upper part of FIG. 2 is a view in the xy plane when step ST1 is performed. The lower part of FIG. 2 is a cross-section taken along line A-A when step ST1 is performed.

[0012] The laminated steel sheet of the rotor core and the laminated steel sheet of the stator core are manufactured from electromagnetic steel sheets in the order of the rotor core and the stator core. In the upper part of FIG. 2, the portions corresponding to the laminated steel sheet 11 of the rotor core and the laminated steel sheet 12 of the stator core core among the electromagnetic steel sheets 10 are indicated by dotted lines. Note that the under hole 30 and the magnet hole 31 of the rotor are shown in the upper part of FIG. 2.

[0013] The manufacturing method of the laminated steel sheet according to Embodiment 1 forms the laminated steel sheet 11 of the rotor core from the electromagnetic steel sheet 10. The rotor core is formed by laminating the laminated steel sheets 11. That is, the laminated steel sheet 11 can also be said to be a laminated plate of the rotor core.

[0014] First, as shown in FIG. 1, by pressing the bridge portion of the electromagnetic steel sheet from above and below, the width direction of the bridge portion is thickened (step ST1). Step ST1 is referred to as a thickening process.

[0015] Referring to FIG. 2, the thickening process will be described in detail. As shown in the lower part of FIG. 2, one end of the bridge portion B1 in the width direction, which is the end R1 on the outer peripheral side of the rotor core, is gripped by pads PA1 from both sides in the vertical direction.

[0016] Also, as shown in the lower part of FIG. 2, the other end of the bridge portion B1 in the width direction, which is the end R2 on the inner peripheral side of the rotor core, is pressed by a punch P1 in the vertical direction. The portion pressed by the punch P1 corresponds to the pressing portion S1 shown in the upper part of FIG. 2. As shown in the lower part of FIG. 2, the bridge portion B1 of the electromagnetic steel sheet pressed by the punch P1 leaks meat from the end R2 toward the central portion and thickens. The thickened central portion of the bridge portion B1 of the electromagnetic steel sheet is referred to as the thickening 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 ST2). Step ST2 is referred to as the bending process.

[0018] Next, as shown in FIG. 1, both surfaces of the bridge portion of the electromagnetic steel sheet are restrained to crush the bridge portion to its original thickness (step ST3). Step ST3 is referred to as the crushing process. In step ST3, the bridge portion B1 of the electromagnetic steel sheet is restrained by a die from below and by a punch and pads from above. Among the bridge portion B1 of the electromagnetic steel sheet, the punch is used to restrain the upper side of the end R2 and the thickening portion V1. Among the bridge portion B1 of the electromagnetic steel sheet, pads are used to restrain the upper side other than the end R2 and the thickening portion V1 (corresponding to the end R1). In the crushing process, the warping due to the elongation of the bridge portion B1 is corrected and the bridge portion B1 is made to its original thickness.

[0019] Next, as shown in FIG. 1, the bridge of the laminated steel sheet of the rotor core is punched out from the bridge portion of the electromagnetic steel sheet (step ST4). Step ST4 is referred to as the punching process.

[0020] The manufacturing method of the laminated steel sheet according to Embodiment 1 can form the bridges of the laminated steel sheet of the rotor core by Steps ST1 to ST4. Also, the manufacturing method of the laminated steel sheet according to Embodiment 1 can work-harden the bridges of the laminated steel sheet of the rotor core by Steps ST1 to ST4. Note that the above-mentioned punch has an R-shaped end in order to prevent cracking of the object to be pressed.

[0021] <Manufacturing method of the laminated steel sheet according to the comparative example> Subsequently, with reference to FIG. 3, the manufacturing method of the laminated steel sheet according to the comparative example will be described. FIG. 3 is a schematic diagram showing the manufacturing method of the laminated steel sheet according to the comparative example. In the manufacturing method of the laminated steel sheet according to the comparative example, the processing corresponding to Step ST1 shown in FIG. 1 is different. Since the other configurations are the same as those of the manufacturing method of the laminated steel sheet according to Embodiment 1, the description thereof will be omitted. The upper part of FIG. 3 is a view in the xy plane when performing the processing corresponding to Step ST1. The lower part of FIG. 3 is a cross-section taken along line A-A when performing the processing corresponding to Step ST1.

[0022] As shown in the lower part of FIG. 3, in the manufacturing method of the laminated steel sheet according to the comparative example, the end R2 on the inner peripheral side of the rotor core, which is the other end in the width direction of the bridge portion B1, is pressed from above and below by the punch P1. The portion pressed by the punch P1 corresponds to the pressing portion S1 shown in the upper part of FIG. 3. The pressing portion S1 shown in the lower part of FIG. 3 is the same as the pressing portion S1 shown in the upper part of FIG. 2.

[0023] As shown in the lower part of FIG. 3, in the manufacturing method of the laminated steel sheet according to the comparative example, the end R1 on the outer peripheral side of the rotor core, which is one end in the width direction of the bridge portion B1, is pressed from above and below by the punch P2. The portion pressed by the punch P2 corresponds to the pressing portion S2 shown in the upper part of FIG. 3. That is, in the manufacturing method of the laminated steel sheet according to the comparative example, as shown in FIG. 3, both ends in the width direction of the bridge portion B1 are pressed from above and below.

[0024] Here, the pressing portion S2 includes a portion that will later correspond to the laminated steel plate 12 of the stator core. That is, the pressing portion S2 is a portion that serves as an outer peripheral side bridge of the laminated steel plate 11 of the rotor core that is taken together with the laminated steel plate 12 of the stator. When the end portion R1 on the outer peripheral side of the rotor core is pressed by the punch P2 from the vertical direction, the portion corresponding to the laminated steel plate 12 of the stator core will be crushed. As a result, not only does the plate thickness of the stator decrease, but the magnetic permeability also decreases, so the magnetic flux decreases and the torque of the motor decreases.

[0025] In contrast, in the method for manufacturing a laminated steel plate according to Embodiment 1, as shown in FIG. 2, the pressing portion S1 is pressed by the punch P1, but the portion corresponding to the pressing portion S2 shown in the upper part of FIG. 3 is gripped from the vertical direction by the pad PA1. Thereby, it is possible to suppress the portion corresponding to the laminated steel plate of the stator core from being crushed.

[0026] Furthermore, in the method for manufacturing a laminated steel plate according to Embodiment 1, as shown in the lower part of FIG. 2, the bridge portion B1 of the electromagnetic steel plate pressed by the punch P1 thins out from the end portion R2 toward the central portion and thickens. Thereby, the strength of the outer peripheral side end portion of the bridge of the laminated steel plate can be improved. Therefore, in the method for manufacturing a laminated steel plate according to Embodiment 1, it is possible to strengthen the outer peripheral bridge of the rotor core while suppressing a decrease in the plate thickness of the stator and ensuring the torque of the motor.

[0027] In this way, in the method for manufacturing a laminated steel plate according to the present disclosure, while gripping the end portion on one end in the width direction of the bridge portion and on the outer peripheral side of the rotor core from both sides, the end portion on the other end in the width direction of the bridge portion and on the inner peripheral side of the rotor core is pressed from the vertical direction. With such a configuration, it is possible to manufacture a laminated steel plate in which the outer peripheral bridge of the rotor core is strengthened while ensuring the torque of the motor.

[0028] Note that the present invention is not limited to the above-described embodiments, and can be appropriately modified without departing from the spirit 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 embodiments within the scope of the present invention.

Explanation of Reference Numerals

[0029] 10 Electromagnetic steel sheet 11, 12 Laminated steel sheet 30 Counterbore 31 Magnet hole B1 Bridge portion P1, P2 Punch PA1 Pad R1, R2 End portion S1, S2 Pressing portion V1 Build-up portion

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 bending step of pressing one surface of the bridge portion to project the bridge portion from the electromagnetic steel sheet; a step of restraining both surfaces of the bridge portion to crush the bridge portion to its original thickness; and in the thickening step, while gripping one end in the width direction of the bridge portion, which is the end on the outer peripheral side of the rotor core, from both surfaces, pressing the other end in the width direction of the bridge portion, which is the end on the inner peripheral side of the rotor core, from above and below; a method for manufacturing a laminated steel sheet.

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