CN115694099A - Rotor core manufacturing method and rotor core manufacturing device - Google Patents

Abstract

The invention provides a method for manufacturing a rotor core, which can improve the productivity of the rotor core. The method for manufacturing a rotor core includes a shaft hole penetrating in an axial direction and a key portion protruding radially inward from an inner periphery of the shaft hole, and a plurality of plate-like rotor core members are stacked in a thickness direction while being rotated in a circumferential direction. The method for manufacturing a rotor core according to the present embodiment includes: a first through-hole forming step of punching first through-holes, each of which forms an outline of a plurality of convex portions including convex portions constituting a key portion, in an electromagnetic steel sheet; a second through-hole forming step of forming a second through-hole by cutting off a part of the plurality of convex portions; and a shaft hole forming step of punching out a region of the electromagnetic steel sheet, at least a portion of which overlaps the first through hole and the second through hole in a plan view of the electromagnetic steel sheet, to form a shaft hole.

Description

Rotor core manufacturing method and rotor core manufacturing device

Technical Field

The present invention relates to a rotor core manufacturing method and a rotor core manufacturing apparatus.

Background

As a method for manufacturing a rotor core, a method is known in which a steel plate is punched out in the shape of a rotor core component by a punching device or the like, and a plurality of punched rotor core components are stacked in the thickness direction.

As a method for manufacturing a rotor core as described above, for example, a method for manufacturing a rotor core disclosed in patent document 1 is known. The method for manufacturing a rotor core disclosed in patent document 1 includes: a first step of forming a contour of a key portion in a thin strip-shaped metal plate, and punching a punched hole having an inner region located inside a shaft hole and an outer region continuous to the inner region and located outside the shaft hole; a second step of blanking a shaft hole communicating with the blanking hole; and a third step of punching out the outer shape of the core piece having the shaft hole formed therein and laminating the core piece.

In the method for manufacturing a rotor core disclosed in patent document 1, in the first step, punched holes constituting the key portions are formed in the first core piece at 0-degree positions and 180-degree positions, and punched holes constituting the key portions are formed in the second core piece at 90-degree positions and 270-degree positions. In the method of manufacturing a rotor core, the first core segment and the second core segment are alternately laminated while being rotationally laminated by 90 degrees, thereby obtaining the rotor core.

Documents of the prior art

Patent document

Patent document 1: japanese unexamined patent publication No. 2014-171329

Disclosure of Invention

In the method for manufacturing a rotor core disclosed in patent document 1, two types of core pieces, i.e., a first core piece and a second core piece, are formed in a first step. In such a manufacturing method, for example, when manufacturing a rotor core in which the key portions are offset in the circumferential direction of the rotor core (rotor core), it is necessary to form core pieces having the key portions at positions shifted in the circumferential direction with respect to the key portions of the core pieces of each type, in addition to the two types of core pieces. Therefore, in the case of manufacturing the above-described rotor core using the above-described manufacturing method, it is necessary to form a total of four core pieces. In the above-described manufacturing method, since a step of forming various types of core pieces is required, four steps are required to form four types of core pieces.

As described above, in the manufacturing method disclosed in patent document 1, when the rotor core or the like is manufactured such that the key portion is deviated in the circumferential direction of the rotor core (rotor core), the number of steps increases, and the tact time for manufacturing the rotor core increases. In contrast, a method for manufacturing a rotor core is desired that can shorten the tact time for manufacturing a rotor core and improve the productivity of the rotor core.

The invention aims to provide a rotor core manufacturing method capable of improving the productivity of a rotor core.

A method for manufacturing a rotor core according to an embodiment of the present invention is a method for manufacturing a rotor core having a shaft hole that penetrates in an axial direction and a key portion that protrudes radially inward on an inner circumference of the shaft hole, and configured by stacking a plurality of plate-like rotor core members in a thickness direction while rotating the rotor core members in a circumferential direction. The method for manufacturing the rotor core comprises the following steps: a first through-hole forming step of punching a first through-hole, which forms a contour of each of a plurality of convex portions including the convex portion constituting the key portion, in the sheet material; a second through-hole forming step of forming a second through-hole by cutting off a part of the plurality of projections; and a shaft hole forming step of punching out a region in which at least a part of the plate material overlaps with the first through-hole and the second through-hole in a plan view of the plate material, thereby forming a through-hole constituting a part of the shaft hole.

A rotor core manufacturing apparatus according to an embodiment of the present invention is a rotor core manufacturing apparatus for manufacturing a rotor core having a shaft hole penetrating in an axial direction and a key portion protruding radially inward on an inner periphery of the shaft hole, and configured by stacking a plurality of plate-like rotor core members in a thickness direction while rotating one side in a circumferential direction. The rotor core manufacturing apparatus includes: a first through-hole forming portion that punches a first through-hole, which forms an outline of each of the plurality of protruding portions constituting the key portion, in the sheet material; a second through-hole forming portion that forms a second through-hole by cutting off a part of the plurality of convex portions; and a shaft hole forming portion that forms a through hole constituting a part of the shaft hole by punching out a region in which at least a part of the plate material overlaps with the first through hole and the second through hole in a plan view of the plate material.

Effects of the invention

According to the method for manufacturing a rotor core of an embodiment of the present invention, it is possible to realize a method for manufacturing a rotor core that can improve the productivity of the rotor core.

Drawings

Fig. 1 is a perspective view showing a schematic structure of a rotor core according to an embodiment.

Fig. 2 is a plan view showing a schematic structure of a rotor core component constituting a rotor core.

Fig. 3 is a flowchart illustrating an example of a method of manufacturing a rotor core.

Fig. 4 is a plan view schematically showing an example of a method of manufacturing a rotor core component from an electromagnetic steel sheet.

Fig. 5 is a plan view schematically showing an example of a method of manufacturing a rotor core component from electromagnetic steel sheets.

Fig. 6 is an enlarged view of the first through hole.

Fig. 7 is a view schematically showing an example of a rotor core formed by rotationally laminating rotor core members.

Fig. 8 is a diagram schematically showing an example of a rotor core manufacturing apparatus.

Fig. 9 is a diagram schematically showing an example of the punch driving mechanism of the second through-hole forming portion.

Fig. 10 is a diagram schematically showing an example of a punch driving mechanism of the second through hole forming portion.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding portions are denoted by the same reference numerals, and description thereof will not be repeated. The dimensions of the components in the drawings do not faithfully represent the actual dimensions of the components, the dimensional ratios of the components, and the like.

In the following description, a direction parallel to the center axis P of the rotor core 1 is referred to as an "axial direction", a direction perpendicular to the center axis P is referred to as a "radial direction", and a direction along an arc centered on the center axis P is referred to as a "circumferential direction". However, the orientation of the motor having the rotor core 1 of the present invention in use is not intended to be limited by the definition of the direction.

In the following description, the expressions such as "fixed", "connected", and "attached" include not only the case where the components are directly fixed to each other, but also the case where the components are fixed via other components. In other words, in the following description, expressions such as fixing include direct and indirect fixing of members.

(Structure of rotor core)

Fig. 1 is a diagram showing a schematic structure of a rotor core 1 according to an embodiment of the present invention. The rotor core 1 constitutes a part of a rotor of a motor not shown. The rotor core 1 is a cylindrical member formed by stacking a plurality of disc-shaped rotor core members 20 in the thickness direction. That is, the rotor core 1 has a cylindrical shape extending along the central axis P.

Further, although not particularly shown, the rotor core 1 may have a magnet insertion hole into which the rotor magnet is inserted, or may have a recess portion on the radially outer side for disposing the rotor magnet.

The rotor core 1 has a shaft hole 11 extending along the central axis P at the center when the rotor core 1 is viewed in the axial direction, which is the direction in which the central axis P extends. A shaft of a rotor, not shown, penetrates the shaft hole 11.

The rotor core 1 has a plurality of keys 12 protruding toward the inside of the shaft hole 11 on the inner surface of the shaft hole 11. In the present embodiment, the rotor core 1 has two keys 12 on the inner surface of the shaft hole 11.

When the rotor core 1 is viewed in the axial direction, the two key portions 12 are located at positions facing each other on the inner surface of the shaft hole 11. When the rotor core 1 is viewed in the axial direction, each of the two key portions 12 has a rectangular shape. The two keys 12 extend in the axial direction on the inner surface of the shaft hole 11.

The two keys 12 are fitted in a recess provided on the outer peripheral surface of a shaft of a rotor, not shown. This enables the rotation of the shaft to be transmitted to the rotor core 1. Thereby, the rotor core 1 rotates together with the shaft.

Fig. 2 is a view showing a schematic structure of a rotor core member 20 constituting the rotor core 1. As shown in fig. 2, the rotor core member 20 is a disk-shaped magnetic steel plate and has a through hole 21 in the center in a plan view. The through-hole 21 constitutes a part of the shaft hole 11.

Rotor core member 20 has a plurality of protruding portions 22 on the inner circumferential side of through-hole 21. The plurality of protruding portions 22 are located at positions facing the inner peripheral side of the through-hole 21 in a plan view of the rotor core component 20. In the present embodiment, the rotor core member 20 has a pair of protruding portions 22. The pair of projections 22 constitutes a part of the key 12.

As will be described in detail later, the plurality of rotor core components 20 constituting the rotor core 1 are stacked while being rotated by a predetermined angle in the circumferential direction. That is, the rotor core 1 is configured by rotatably stacking a plurality of rotor core members 20. As a result, as described later, variations in magnetic properties of the rotor core component 20 formed of the electromagnetic steel sheets 100 can be reduced, and therefore, the magnetic properties of the rotor core 1 can be improved.

(method of manufacturing rotor core)

Next, a method for manufacturing the rotor core 1 having the above-described structure will be described. Fig. 3 is a flowchart illustrating an example of the method of manufacturing the rotor core 1. Fig. 4 and 5 are views schematically showing an example of a method of manufacturing the rotor core component 20 from the strip-shaped electromagnetic steel sheet 100. Fig. 6 is an enlarged view of the first through-hole 101. Fig. 7 is a view schematically showing a case where the rotor core members 20 are stacked by rotation in the thickness direction.

In fig. 4 and 5, a rotor magnet insertion hole for inserting a rotor magnet is not shown. In the following description, a description of a method for manufacturing the rotor magnet insertion hole of the rotor core member 20 and the like will be omitted.

As shown in fig. 3, the rotor core 1 first forms a plurality of first through holes 101 in a strip-shaped magnetic steel sheet 100 in a first through hole forming step of step S1. In the present embodiment, in the first through-hole forming step, four first through-holes 101 are formed in the electromagnetic steel sheet 100 at 90-degree intervals in the circumferential direction. A pair of first through holes 101 among the four first through holes 101 is aligned in the short side direction of the magnetic steel sheet 100, and the other pair of first through holes 101 is aligned in the long side direction of the magnetic steel sheet 100. The electromagnetic steel sheet 100 corresponds to the sheet of the present invention.

As shown in fig. 6, the first through-hole 101 is a C-shaped through-hole in a plan view. Specifically, the first through-hole 101 includes a first slit 102 extending in a first direction and a pair of second slits 103 extending in a second direction orthogonal to the first direction from both ends of the first slit 102 and in the same direction. The first slit 102 is connected to a pair of second slits 103. The length of the pair of second slits 103 in the second direction is shorter than the length of the first slit 102 in the first direction. The first direction is a longitudinal direction of the first slit 102.

As shown in fig. 4 and 5, the first slits 102 are located closer to the center C of the rotor core member 20 than the pair of second slits 103. The magnetic steel sheet 100 is formed with a projection 104 that projects toward the center C in a plan view, through the first slit 102 and the pair of second slits 103. That is, the electromagnetic steel sheet 100 has a plurality of protrusions 104 protruding toward the center C formed by the plurality of first through holes 101. In this way, in the first through-hole forming step, a plurality of first through-holes 101 are formed, and the plurality of first through-holes 101 form the contours of the plurality of convex portions 104. In addition, the plurality of convex portions 104 include convex portions 104 that become the protruding portions 22 of the rotor core component 20, wherein the protruding portions 22 of the rotor core component 20 constitute the key portions 12 of the rotor core 1.

In the present embodiment, four projections 104 are formed on the electromagnetic steel sheet 100 at intervals of 90 degrees in the circumferential direction. One pair of the four projections 104 is arranged in the short side direction of the magnetic steel sheet 100, and the other pair of the projections 104 is arranged in the long side direction of the magnetic steel sheet 100.

Next, in a second through-hole forming step of step S2 shown in fig. 3, a plurality of second through-holes 111 are formed in the electromagnetic steel sheet 100. The second through-hole 111 has a rectangular shape in plan view and has a size that enables the projection 104 formed by the first through-hole 101 to be cut off. The second through-hole 111 is formed at a position where a part of the plurality of convex portions 104 formed by the plurality of first through-holes 101 is cut out.

Specifically, the second through-hole 111 is formed at a position where a pair of projections 104 aligned in the short side direction of the magnetic steel sheet 100 or another pair of projections 104 aligned in the long side direction of the magnetic steel sheet 100 is cut off. Fig. 4 shows a case where the pair of projections 104 aligned in the short side direction of the electromagnetic steel sheet 100 is cut out through the second through-hole 111. Fig. 5 shows a case where another pair of projections 104 aligned in the longitudinal direction of the electromagnetic steel sheet 100 is cut out through the second through-hole 111.

The cut-off convex portion 104 includes not only a case where only the convex portion 104 is cut but also a case where a punched hole is formed in a predetermined range including the convex portion 104.

In the manufacturing process of the rotor core 1, as the second through-hole forming process, a case where one pair of the projections 104 aligned in the longitudinal direction of the electromagnetic steel sheet 100 is cut out by the second through-hole 111 and a case where the other pair of the projections 104 aligned in the short-side direction of the electromagnetic steel sheet 100 is cut out by the second through-hole 111 are alternately performed. That is, in the present embodiment, the second through-hole forming step includes: a first projection cutting step of cutting a pair of projections 104, which are opposed to each other in the radial direction, out of the four projections 104 as shown in fig. 4; and a second projection cutting step of cutting off the other pair of projections 104 opposed to each other in the radial direction among the four projections 104 as shown in fig. 5. In the second through-hole forming step of the present embodiment, the first protrusion cutting step and the second protrusion cutting step are alternately performed. In fig. 4, a pair of second through holes 111 aligned in the longitudinal direction of the electromagnetic steel sheet 100 is formed. In fig. 5, a pair of second through holes 111 aligned in the short side direction of the electromagnetic steel sheet 100 is formed. The protruding portions 104 remaining without being cut by the second through-hole forming process become the protruding portions 22 of the rotor core component 20.

By forming the second through-holes 111 in the second through-hole forming step, the rotor core component 20 from which the pair of projections 104 aligned in the longitudinal direction of the magnetic steel sheet 100 is cut and the rotor core component 20 from which the other pair of projections 104 aligned in the short direction of the magnetic steel sheet 100 is cut are alternately manufactured after steps S3 and S4 described later.

Further, the step of cutting out the pair of projections 104 aligned in the longitudinal direction of the magnetic steel sheet 100 through the second through hole 111 may be performed as the second through hole forming step a predetermined number of times, and then the step of cutting out the other pair of projections 104 aligned in the short direction of the magnetic steel sheet 100 through the second through hole 111 may be performed as the second through hole forming step. The step of cutting out the other pair of projections 104 aligned in the short side direction of the magnetic steel sheet 100 through the second through hole 111 may be performed as the second through hole forming step a predetermined number of times, and then the step of cutting out the pair of projections 104 aligned in the long side direction of the magnetic steel sheet 100 through the second through hole 111 may be performed as the second through hole forming step. As described above, in the second through-hole forming step, the position of the projection 104 to be cut out of the plurality of projections 104 may be changed when punching out each electromagnetic steel sheet 100 a predetermined number of times. The predetermined number of times may be 1 time or a plurality of times.

Next, in the shaft hole forming step of step S3 shown in fig. 3, the through hole 21 constituting a part of the shaft hole 11 is formed in the electromagnetic steel sheet 100. As shown in fig. 4 and 5, the through-hole 21 is a through-hole connecting the first through-holes 101 and the second through-holes 111. Specifically, the through-hole 21 is continuous with the pair of second slits 103 among the plurality of first through-holes 101, and is continuous with the pair of second through-holes 111. The through-hole 21 is connected to the opposite side of the pair of second slits 103 from the first slit 102 in the above-described second direction shown in fig. 6. As shown in fig. 4 and 5, the through-hole 21 is connected to the short sides of the pair of rectangular second through-holes 111. In this way, the through-hole 21 is formed by punching out a region of the magnetic steel sheet 100 where at least a portion overlaps with the first through-hole 101 and the second through-hole 111.

Thus, through-hole 21 having protrusion 22 on the inner peripheral side is formed in electromagnetic steel sheet 100. Further, when the through-hole 21 is formed, the through-hole 21 is continuous with the pair of second slits 103 and continuous with the pair of second through-holes 111, and therefore, the peripheral edge portion of the first through-hole 101 and the peripheral edge portion of the second through-hole 111 in the electromagnetic steel sheet 100 can be prevented from being removed twice.

In the shaft hole forming step, as will be described later, the through hole 21 is formed in the electromagnetic steel sheet 100 using a punch and a die having a concave portion recessed along the shape of the convex portion 104, which is not cut out in the second through hole forming step, among the plurality of convex portions 104.

In the outer shape punching step of step S4 shown in fig. 3, the outer shape of the rotor core component 20 is punched out of the electromagnetic steel sheet 100. Thereby, the rotor core member 20 is obtained. Although the description is omitted in the above description, rotor magnet insertion holes and the like are also formed in the rotor core member 20. Thus, when the outer shape of the rotor core component 20 is punched out of the magnetic steel sheet 100, the magnetic steel sheet 100 is punched out after the rotor magnet insertion holes and the like are also formed in the magnetic steel sheet 100.

Then, in the rotor core component stacking step of step S5 shown in fig. 3, a plurality of rotor core components 20 are stacked in the thickness direction. Specifically, the rotor core components 20 in which one pair of projections 104 arranged in the longitudinal direction of the magnetic steel sheet 100 is cut off and the rotor core components 20 in which the other pair of projections 104 arranged in the short direction of the magnetic steel sheet 100 is cut off are alternately stacked in the thickness direction. As shown in fig. 7, the rotor core components 20 in which the other pair of projections 104 arranged in the short-side direction of the electromagnetic steel sheet 100 are cut out are laminated in a state rotated by 90 degrees in the circumferential direction, for example, with respect to the rotor core components 20 in which the pair of projections 104 arranged in the long-side direction of the electromagnetic steel sheet 100 are cut out. In this way, the plurality of rotor core members 20 are rotatably stacked.

By the above method, the rotor core 1 in which the plurality of rotor core components 20 are stacked in the thickness direction can be obtained.

The method for manufacturing a rotor core according to the present embodiment is a method for manufacturing a rotor core 1, and the rotor core 1 has a shaft hole 11 penetrating in an axial direction and a key portion 12 protruding radially inward on the inner periphery of the shaft hole 11, and is configured by stacking a plurality of plate-like rotor core members 20 in a thickness direction while rotating in a circumferential direction. The method for manufacturing a rotor core according to the present embodiment includes: a first through-hole forming step of punching first through-holes 101, each of which forms an outline of a plurality of convex portions 104 including convex portions 104 constituting the key portion 12, in the electromagnetic steel sheet 100; a second through-hole forming step of forming a second through-hole 111 by cutting out a part of the plurality of convex portions 104; and a shaft hole forming step of punching out a region in which at least a part of the magnetic steel sheet 100 overlaps the first through-hole 101 and the second through-hole 111 when the magnetic steel sheet 100 is viewed in a plan view, thereby forming the through-hole 21 constituting a part of the shaft hole 11.

Thus, the plate-like rotor core members 20 are stacked in the thickness direction while being rotated in the circumferential direction, whereby the rotor core 1 having the key portions 12 on the inner periphery of the shaft hole 11 can be formed. That is, by cutting out a part of the plurality of protruding portions 104 in the second through-hole forming step, even when the rotor core members 20 are stacked in the thickness direction while being rotated in the circumferential direction, the key portions 12 can be formed at the same positions in the circumferential direction of the inner circumference of the shaft hole 11 on the rotor core 1.

However, for example, in the case of a configuration in which the key portion 12 is offset in the circumferential direction of the shaft hole 11, the rotor core member 20 needs to have the protruding portions 104 formed at positions offset in the circumferential direction of the shaft hole 11. In this case, if two types of rotor core members are formed in which the positions of the protruding portions 104 are different by the rotational angle in the circumferential direction in order to laminate the rotor core members 20 in the thickness direction while rotating the rotor core members in the circumferential direction, it is necessary to prepare a rotor core member in which the positions of the protruding portions 104 are shifted in the circumferential direction among the various rotor core members. Therefore, a total of four rotor core components need to be prepared. If four kinds of rotor core components are prepared in this way, four steps are required.

In contrast, in the above configuration, the position of the remaining convex portion 104 can be controlled by cutting out a part of the plurality of convex portions 104 formed in the first through-hole forming step in the second through-hole forming step. Therefore, in the case of the structure in which the key portions 12 are deviated in the circumferential direction of the shaft hole 11, if two types of rotor core components in which the positions of the protruding portions 104 are shifted in the circumferential direction are prepared, the positions of the protruding portions 104 remaining in the second through-hole forming step are controlled, and the above-described four types of rotor core components can be obtained. In this way, in the above configuration, four types of rotor core components can be obtained through three steps.

Therefore, as described above, in the method for manufacturing the rotor core requiring four or more types of rotor core components, the tact time can be shortened. Therefore, the productivity of the rotor core 1 can be improved. Further, since the number of steps is small, the rotor core manufacturing apparatus 200 for manufacturing the rotor core 1 can be downsized.

In the present embodiment, in the shaft-hole forming step, the through-hole 21 is formed in the electromagnetic steel sheet 100 using a punch and a die having a concave portion recessed along the shape of the convex portion 104 that is not cut out in the second through-hole forming step, among the plurality of convex portions 104.

This can suppress the generation of chips when forming the through-hole 21 in the electromagnetic steel sheet 100, and can form the protrusion 22 and the through-hole 21 constituting the key portion 12 with high accuracy.

In the present embodiment, the present invention further includes: an outer shape punching step of punching the electromagnetic steel sheet 100 in which the through-hole 21 is formed, in an outer shape of the rotor core component 20, thereby forming the rotor core component 20; and a rotor core component stacking step of rotating the rotor core components 20 in the circumferential direction and stacking them in the thickness direction, thereby obtaining the rotor core 1.

The electromagnetic steel sheet 100 used when forming the rotor core component 20 may vary in thickness and magnetic properties due to rolling. As described above, by stacking the rotor core members 20 in the thickness direction while rotating in the circumferential direction, it is possible to suppress variations in the dimension of the rotor core 1 in the stacking direction due to variations in the thickness of the rotor core members 20 and to equalize the magnetic characteristics of the rotor core 1.

In the present embodiment, in the second through-hole forming step, when punching is performed a predetermined number of times for each electromagnetic steel sheet 100, the position of the convex portion 104 to be cut out of the plurality of convex portions 104 is changed.

Accordingly, when the portion to be the rotor core member 20 is punched first and when the portion to be the rotor core member 20 is punched next, the position of the protruding portion 104 remaining on the inner periphery of the through-hole 21 can be easily changed. When the rotor core members 20 are stacked in the thickness direction while being rotated in the circumferential direction, it is necessary to change the positions of the protruding portions 104 remaining on the inner periphery of the through-holes 21 in order to form the key portions 12 on the inner periphery of the rotor core 1. According to the above configuration, when the rotor core members 20 are laminated in this manner, the position of the convex portion 104 remaining on the inner periphery of the through-hole 21 can be easily changed. This enables the rotor core 1 to be easily formed using the rotor core member 20.

In the present embodiment, in the first through-hole forming step, four convex portions 104 are formed on the electromagnetic steel sheet 100 at equal intervals in the circumferential direction as the plurality of convex portions 104. The second through-hole forming step includes: a first projection cutting step of cutting a pair of projections 104 facing each other in the radial direction out of the four projections 104; and a second projection cutting step of cutting out another pair of projections 104 opposed to each other in the radial direction from among the four projections 104. In the rotor core component stacking step, the rotor core components 20 from which the one pair of projections 104 are cut out are stacked in the thickness direction while being rotated by 90 degrees in the circumferential direction with respect to the rotor core components 20 from which the one pair of projections 104 are cut out.

Thus, in the rotor core 1 formed by stacking the rotor core members 20 in the thickness direction while rotating them 90 degrees in the circumferential direction, the pair of key portions 12 can be formed on the inner periphery of the shaft hole 11.

(rotor core manufacturing apparatus)

Next, a rotor core manufacturing apparatus 200 for realizing the above-described method of manufacturing the rotor core 1 will be described. Fig. 8 is a diagram showing a schematic configuration of a rotor core manufacturing apparatus 200.

As shown in fig. 8, the rotor core manufacturing apparatus 200 includes a first through-hole forming portion 210, a second through-hole forming portion 220, a shaft hole forming portion 230, and an outer shape blanking portion 240.

The first through-hole forming portion 210 forms a plurality of first through-holes 101 for forming the plurality of convex portions 104 in the electromagnetic steel sheet 100. The first through-hole forming section 210 includes a first fixed die 211 and a first movable die 212. For example, the first movable die 212 includes a first punch 213 that forms the first through hole 101. The first movable die 212 moves in the hollow arrow direction of fig. 8 relative to the first fixed die 211, and the first through hole 101 is formed in the electromagnetic steel sheet 100 by the first punch 213.

The second through hole forming portion 220 forms a plurality of second through holes 111 in the electromagnetic steel sheet 100. The second through-hole forming part 220 has a second fixed die 221 and a second movable die 222. For example, the second movable die 222 has a second punch 223 that forms the second through-hole 111. The second movable die 222 moves in the direction of the outlined arrow in fig. 8 with respect to the second stationary die 221, whereby the second through-hole 111 is formed in the electromagnetic steel sheet 100 by the second punch 223.

The second through hole forming portion 220 is formed by forming the second through hole 111 in the electromagnetic steel sheet 100, and cuts out a part of the plurality of convex portions 104 formed by the plurality of first through holes 101. The second through-hole forming portion 220 changes the protruding portion 104 to be cut out of the plurality of protruding portions 104 in the order of punching the rotor core component 20. In the present embodiment, the second through hole forming portions 220 alternately perform cutting of one pair of the convex portions 104 arranged in the short side direction of the electromagnetic steel sheet 100 out of the four convex portions 104 and cutting of the other pair of the convex portions 104 arranged in the long side direction of the electromagnetic steel sheet 100.

The second through-hole forming part 220 has a punch driving mechanism 225 that selects a convex part 104 to be cut out of the plurality of convex parts 104. Fig. 9 and 10 are views showing an example of a schematic configuration of the punch driving mechanism 225 of the second through hole forming portion 220. In fig. 9 and 10, only a part of the structure is shown in cross section for the sake of explanation. In fig. 9 and 10, for the sake of explanation, a configuration of a punch driving mechanism 225 capable of selecting punching or non-punching of one convex portion 104 is schematically shown.

The punch driving mechanism 225 has a slide member 226, a driving portion 227, a cam 228, and a support portion 229.

The slide member 226 is a plate-like member extending in the horizontal direction. One end of the slide member 226 in the longitudinal direction is connected to the driving section 227. The slide member 226 can be moved in the horizontal direction, i.e., the longitudinal direction, by the driving section 227. The slide member 226 has a recess 226a at the other end in the longitudinal direction, which can receive an end of the cam 228.

The driving section 227 generates a driving force for moving the slide member 226 in the horizontal direction, i.e., the longitudinal direction of the slide member 226. The driving section 227 has an actuator 227a such as an air cylinder and a driving connecting section 227b capable of reciprocating by the actuator 227 a. The driving connection portion 227b is connected to one end portion of the slide member 226 in the longitudinal direction. The actuator 227a may be any actuator as long as it can move the slide member 226 in the horizontal direction, that is, in the longitudinal direction of the slide member 226, and may have another structure such as a piezoelectric element.

The cam 228 is a columnar member extending in the axial direction. The cam 228 is located in a through hole 229a provided in the support portion 229 and is movable in the axial direction. One end portion in the axial direction of the cam 228 is connected to the second punch 223. The second punch 223 is also located in the through hole 229a of the support 229 so as to be movable in the axial direction.

The other end portion of the cam 228 in the axial direction can be housed in the recess 226a of the slide member 226.

As shown in fig. 9, when the second movable die 222 is pressed in a direction to approach the second fixed die 221 in a state where the recess 226a of the slide member 226 is positioned in the axial direction of the cam 228 with respect to the cam 228, the cam 228 and the second punch 223 move in the axial direction, and the other end portion of the cam 228 in the axial direction is accommodated in the recess 226a. Therefore, the second through-hole 111 is not formed in the electromagnetic steel sheet 100 by the second punch 223. That is, the punch driving mechanism 225 positions the second punch 223 at the non-blanking position.

On the other hand, as shown in fig. 10, when the second movable die 222 is pressed in a direction to approach the second fixed die 221 in a state where the recess 226a of the slide member 226 is located at a position other than the cam 228 in the axial direction of the cam 228, the cam 228 and the second punch 223 do not move in the axial direction. Therefore, the second through-hole 111 can be formed in the electromagnetic steel sheet 100 by the second punch 223. That is, the punch driving mechanism 225 positions the second punch 223 at the blanking position.

In this way, the punch driving mechanism 225 can position the second punch 223 at the blanking position and the non-blanking position.

By providing the second through-hole forming portion 220 with the punch driving mechanism 225 described above, the cutting of one pair of the convex portions 104 aligned in the short side direction of the electromagnetic steel sheet 100 out of the four convex portions 104 and the cutting of the other pair of the convex portions 104 aligned in the long side direction of the electromagnetic steel sheet 100 can be performed alternately. That is, the second through-hole forming portion 220 includes the punch driving mechanism 225 capable of positioning the plurality of second punches 223 at the punching position and the non-punching position, respectively, so that when the punch driving mechanism 225 positions a part of the second punches 223 at the punching position and cuts off the pair of convex portions 104, the other second punches 223 are positioned at the non-punching position by the punch driving mechanism 225. When the other second punch 223 is positioned at the punching position by the punch driving mechanism 225 and the other pair of convex portions 104 is cut, the part of the second punch 223 is positioned at the non-punching position by the punch driving mechanism 225.

The shaft hole forming portion 230 forms a through hole 21 constituting a part of the shaft hole 11 of the rotor core 1 in the electromagnetic steel sheet 100. The shaft hole forming portion 230 has a third fixed die 231 and a third movable die 232. For example, the third movable die 232 has a third punch 233 that forms the through-hole 21. The third movable die 232 moves in the direction of the outlined arrow in fig. 8 relative to the third stationary die 231, whereby the through-hole 21 is formed in the electromagnetic steel sheet 100 by the third punch 233.

The third punch 233 of the shaft-hole forming portion 230 has a concave portion that is recessed along the shape of the convex portion 104 that is not cut by the second through-hole forming portion 220. Although not particularly shown, the third fixing die 231 includes a die having a concave portion recessed along the shape of the convex portion 104 not cut by the second through-hole forming portion 220.

The outer shape blanking portion 240 blanks the outer shape of the rotor core member 20 from the electromagnetic steel sheet 100. The outer shape blanking portion 240 has a fourth fixed die 241 and a fourth movable die 242. For example, the fourth movable die 242 has a fourth punch 243 for punching out the outer shape of the rotor core member 20. The fourth movable die 242 is moved in the hollow arrow direction of fig. 8 with respect to the fourth stationary die 241, whereby the outer shape of the rotor core component 20 is punched out of the electromagnetic steel sheet 100 by the fourth punch 243.

Although not particularly shown, the rotor core manufacturing apparatus 200 further includes a rotary lamination portion that laminates the rotor core members 20 punched out of the electromagnetic steel sheet 100 in the thickness direction while rotating in the circumferential direction.

The rotor core manufacturing apparatus 200 of the present embodiment is an apparatus for manufacturing a rotor core 1, in which the rotor core 1 has a shaft hole 11 penetrating in an axial direction and a key portion 12 protruding radially inward on an inner periphery of the shaft hole 11, and is configured by stacking a plurality of plate-like rotor core members 20 in a thickness direction while rotating in a circumferential direction. The rotor core manufacturing apparatus 200 includes: a first through-hole forming portion 210 that punches first through-holes 101, each of which forms the outline of each of the plurality of protrusions 104 that constitute the key portion 12, out of the electromagnetic steel sheet 100; a second through-hole forming portion 220 that forms a second through-hole 111 by cutting out a part of the convex portion 104 of the plurality of convex portions 104; and a shaft hole forming portion 230 that forms a through hole 21 constituting the shaft hole 11 by punching the magnetic steel sheet 100 in a region where at least a part of the magnetic steel sheet 100 overlaps the first through hole 101 and the second through hole 111 in a plan view.

Thereby, a rotor core manufacturing apparatus 200 capable of realizing the above-described method of manufacturing the rotor core 1 is obtained.

In the present embodiment, the second through-hole forming portion 220 includes: a plurality of second punches 223 that cut out the plurality of convex portions 104, respectively; and a punch driving mechanism 225 that positions the plurality of second punches 223 in the punching direction at a punching position and a non-punching position. The punch driving mechanism 225 positions the remaining second punches 223 of the plurality of second punches 223 at the non-punching position when positioning a part of the second punches 223 of the plurality of second punches 223 at the punching position, and positions the part of the second punches 223 at the non-punching position when positioning the remaining second punches 223 at the punching position.

Thus, when cutting out a part of the plurality of convex portions 104, by switching the positions of a part of the plurality of second punches 223 and the remaining second punches 223 among the plurality of second punches 223, it is possible to cut out different convex portions 104 among the plurality of convex portions 104 in the case where a portion to be the rotor core component 20 is punched out in the magnetic steel sheet 100 first and in the case where a portion to be the rotor core component 20 is punched out in the magnetic steel sheet 100 next. In this way, since different ones of the plurality of convex portions 104 can be cut out using one apparatus, the rotor core manufacturing apparatus 200 can be downsized, and the rotor core 1 having the key portion 12 on the inner periphery of the shaft hole 11 can be obtained even when the rotor core members 20 are stacked in the thickness direction while being rotated in the circumferential direction.

In the present embodiment, the punch driving mechanism 225 includes: a slide member 226 which is a plate-like member extending in a longitudinal direction and moves the plurality of second punches 223 between the punching position and the non-punching position by moving in the longitudinal direction; and a driving unit 227 for moving the slide member 226 in the longitudinal direction.

This makes it possible to easily realize the structure of the punch drive mechanism 225. Further, the plurality of second punches 223 can be moved to the punching position and the non-punching position by moving the slide member 226 in the longitudinal direction by the driving section 227. Therefore, the punch driving mechanism 225 can be realized by a compact structure.

(other embodiments)

The embodiments of the present invention have been described above, but the above embodiments are merely examples for carrying out the present invention. Therefore, the present invention is not limited to the above embodiment, and the above embodiment can be modified as appropriate without departing from the scope of the present invention.

In the above embodiment, the rotor core members 20 are stacked in the thickness direction by rotating them 90 degrees in the circumferential direction. However, the rotor core members may be stacked in the thickness direction by rotating at an angle other than 90 degrees. In this case, the rotor core members are stacked in the thickness direction while being rotated in the circumferential direction at a rotation angle at which the protruding portions of the rotor core members stacked in the thickness direction constitute the key portions of the rotor core. Therefore, the convex portion is formed at a position corresponding to the rotation angle in the circumferential direction of the rotor core member on the inner circumferential side of the through hole of the rotor core member.

In the above embodiment, the through-hole 21 is formed in the electromagnetic steel sheet 100 at one time in the shaft hole forming step. However, in the shaft hole forming step, the through-hole may be formed by punching the electromagnetic steel sheet 100 a plurality of times.

In the above embodiment, the rotor core 1 has two keys 12 on the inner surface of the shaft hole 11. However, the rotor core may have one or more than three keys on the inner surface of the shaft hole. In the above embodiment, the key portion 12 has a rectangular shape when the rotor core 1 is viewed from the axial direction. However, the key portion may have a shape other than a rectangular shape when the rotor core is viewed in the axial direction. In the above embodiment, the two key portions 12 are located at positions opposed to each other on the inner surface of the shaft hole 11. However, the plurality of key portions may be located at positions not opposed to each other on the inner surface of the shaft hole.

The present invention is applicable to a method for manufacturing a rotor core having a shaft hole penetrating in an axial direction and a key portion protruding radially inward in an inner circumferential direction of the shaft hole, and configured by laminating a plurality of plate-like rotor core members in a thickness direction while rotating the rotor core members in the circumferential direction.

Description of the symbols

1. Rotor core

11. Shaft hole

12. Key portion

20. Rotor core component

21. Through hole

22. Projection part

100. Electromagnetic steel sheet

101. The first through hole

102. A first slit

103. Second slit

104. Convex part

111. Second through hole

200. Rotor core manufacturing device

210. A first through hole forming part

211. First fixed die

212. First movable mold

213. First punch

220. Second through hole forming part

221. Second fixed mould

222. Second movable mold

223. Second punch

225. Punch driving mechanism

226. Sliding member

226a recess

227. Driving part

227a actuator

227b drive connection

228. Cam wheel

229. Supporting part

229a penetrating the hole

230. Shaft hole forming part

231. Third fixed die

232. Third movable mold

233. Third punch

240. Contour punch

241. Fourth fixed mould

242. Fourth movable mold

243. And a fourth punch.

Claims (8)

1. A method for manufacturing a rotor core having a shaft hole penetrating in an axial direction and a key portion protruding radially inward in an inner circumferential direction of the shaft hole, and configured by laminating a plurality of plate-like rotor core members in a thickness direction while rotating the rotor core members in the circumferential direction, the method comprising:

a first through-hole forming step of punching a first through-hole, which forms a contour of each of a plurality of convex portions including the convex portion constituting the key portion, in the sheet material;

a second through-hole forming step of forming a second through-hole by cutting off a part of the plurality of convex portions; and

a shaft hole forming step of punching out a region in which at least a part of the plate material overlaps with the first through-hole and the second through-hole in a plan view of the plate material, thereby forming a through-hole constituting a part of the shaft hole.

2. The rotor core manufacturing method according to claim 1,

in the shaft hole forming step, the through-hole is formed in the plate material by using a punch and a die each having a concave portion recessed along a shape of a convex portion of the plurality of convex portions which is not cut out in the second through-hole forming step.

3. The method for manufacturing a rotor core according to claim 1 or 2, further comprising:

an outer shape punching step of punching the plate material in which the through-hole is formed in the outer shape of the rotor core component to form the rotor core component; and

and a rotor core component laminating step of laminating the rotor core components in a thickness direction while rotating the rotor core components in a circumferential direction, thereby obtaining the rotor core.

4. The rotor core manufacturing method according to claim 3,

the second through-hole forming step changes the position of the cut-out convex portion of the plurality of convex portions when punching is performed a predetermined number of times for each plate material.

5. The rotor core manufacturing method according to claim 4,

in the first through-hole forming step, four convex portions are formed on the plate material at equal intervals in the circumferential direction as the plurality of convex portions,

the second through-hole forming step includes:

a first projection cutting step of cutting a pair of projections opposed to each other in the radial direction out of the four projections; and

a second projection cutting step of cutting off another pair of projections opposed to each other in the radial direction among the four projections,

in the rotor core component stacking step, the rotor core components from which the one pair of protruding portions have been cut out are stacked in the thickness direction while being rotated by 90 degrees in the circumferential direction with respect to the rotor core components from which the other pair of protruding portions have been cut out.

6. A rotor core manufacturing apparatus for manufacturing a rotor core having a shaft hole penetrating in an axial direction and a key portion protruding radially inward in an inner circumferential direction of the shaft hole, and configured by stacking a plurality of plate-like rotor core members in a thickness direction while rotating one in the circumferential direction, the apparatus comprising:

a first through-hole forming portion that punches a first through-hole, which forms a contour of each of the plurality of protruding portions constituting the key portion, out of the plate material;

a second through-hole forming portion that forms a second through-hole by cutting out a part of the plurality of convex portions; and

a shaft hole forming portion that forms a through hole constituting a part of the shaft hole by punching out a region in which at least a part overlaps with the first through hole and the second through hole in a plan view of the plate material.

7. The rotor core manufacturing apparatus according to claim 6,

the second through hole forming part includes:

a plurality of punches that cut off the plurality of convex portions, respectively; and

a plurality of punch driving mechanisms that position the plurality of punches in a punching direction at a punching position and a non-punching position,

the punch driving mechanism

Positioning remaining punches of the plurality of punches in the non-blanking position with a portion of the plurality of punches positioned in the blanking position,

positioning the portion of punches in the non-blanking position with the remaining punches positioned in the blanking position.

8. The rotor core manufacturing apparatus according to claim 7,

the punch driving mechanism includes:

a slide member that is a plate-like member extending in a longitudinal direction and moves the plurality of punches to the punching position and the non-punching position by moving in the longitudinal direction; and

a driving section that moves the slide member in the longitudinal direction.

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