JP-7856761-B2 - Electric motor core

Inventors

• 梶田 大暉

Assignees

• ファナック株式会社

Dates

Publication Date

20260511

Application Date

20220531

Claims (10)

1. In the core of an electric motor, Multiple pin holes are formed on the end face of the core. Furthermore, it comprises a plurality of pins to be inserted into each of the plurality of pin holes, At least one of the plurality of pins includes a curved portion that is at least partially curved with respect to the axial direction of the at least one pin, A core in which at least one of the plurality of pin holes into which the at least one pin is inserted is formed to accommodate the curved portion of the at least one pin.
2. The core according to claim 1, wherein the cross-section of at least one pin hole in the radial direction of the core has twofold symmetry.
3. The core according to claim 2, wherein the cross-section is selected from elliptical, oblong, rectangular, or elongated hexagonal shapes.
4. The core according to claim 1, wherein the cross-section of each of the plurality of pins is annular.
5. The core according to claim 2, wherein, when the centrifugal force acting on the core is smaller than the reaction force of the torque acting on the core, the longest line segment connecting the center of the cross-section of at least one pin hole and the edge of the cross-section over the longest distance is positioned in the radial direction of the core.
6. The core according to claim 2, wherein, when the centrifugal force acting on the core is greater than the reaction force of the torque acting on the core, the longest line segment connecting the center of the cross-section of at least one pin hole and the edge of the cross-section over the longest distance is arranged in the circumferential direction of the core.
7. The core according to claim 2, wherein, when the centrifugal force acting on the core is equal to the reaction force of the torque acting on the core, the longest line segment connecting the center of the cross-section of some of the pin holes of the at least one pin hole to the edge of the cross-section over the longest distance is arranged to be inclined clockwise with respect to the radial direction of the core, and the longest portion of the remaining pin hole of the at least one pin hole is arranged to be inclined counterclockwise with respect to the radial direction of the core.
8. The core according to claim 7, wherein the angle of inclination of the longest line segment of the cross-section of some of the pin holes, in a clockwise direction relative to the radial direction of the core, is equal to the angle of inclination of the longest line segment of the remaining pin holes, in a counterclockwise direction relative to the radial direction of the core.
9. The core according to claim 7 or 8, wherein some of the pin holes and the remaining pin holes are arranged every other pin hole or in groups of one or more.
10. The aforementioned core is formed by stacking multiple core plates, Each of the aforementioned multiple core plates has a plurality of through holes corresponding to the plurality of pin holes, The multiple through holes in the multiple core plates are aligned with each other to form the multiple pin holes, The core according to claim 1 or 2, wherein the positions of the plurality of through holes in each of the plurality of core plates are different from each other according to the curved portion of at least one pin.

Description

Embodiments of the present invention relate to the core of an electric motor. The core of an electric motor includes a stator and a rotor that rotates relative to the stator (for example, Japanese Patent Publication No. 2010-259256). Such an electric motor core may be a laminate formed by stacking a plurality of magnetic plates, such as iron plates, carbon steel plates, or electrical steel plates, in the axial direction of the core. Japanese Patent Publication No. 2010-259256 This is a cross-sectional view of an electric motor according to the first embodiment of the present invention.Figure 1 is a radial cross-sectional view of the rotor.This is a partial cross-sectional view of the rotor in the axial direction along the line A-A' in Figure 2A.This figure shows the first modified example of a pinhole.This figure shows a second modified example of a pinhole.This figure shows a third modified example of a pinhole.This is a diagram showing the fourth type of pinhole torture.This is a perspective view of a pin with a C-shaped cross-section and a pin with an annular cross-section.This is a radial partial cross-sectional view of a rotor according to a second embodiment of the present invention.This is a radial partial cross-sectional view of a rotor according to a third embodiment of the present invention.This is a radial partial cross-sectional view of a rotor according to a fourth embodiment of the present invention.This is a radial partial cross-sectional view of the rotor based on another modification in the fourth embodiment.This is a radial partial cross-sectional view of a rotor based on yet another modification in the fourth embodiment.This is a radial partial cross-sectional view of a rotor according to the fifth embodiment of the present invention.This is another radial partial cross-sectional view of a rotor according to the fifth embodiment of the present invention.This is a partial axial cross-sectional view of a rotor according to the fifth embodiment of the present invention. Embodiments of the present invention will be described below with reference to the attached drawings. Throughout all drawings, corresponding components are denoted by the same reference numerals. Figure 1 is a cross-sectional view of an electric motor according to a first embodiment of the present invention. As shown in Figure 1, the electric motor 1 includes a stator 9 and a rotor 10 rotatably supported by the stator 9. A first bearing 7 and a second bearing 8 are arranged on the inner circumferential surface of the stator 9. A shaft portion 5 that passes through the rotor 9 is rotatably supported by the stator 9 by the first bearing 7 and the second bearing 8. A detector 6 for detecting the rotational speed of the shaft portion 5 is attached to one end of the stator 9. In this specification, the rotor 10 of the electric motor 1 will be used as the "core of the electric motor" for explanation. However, please note that the "core of the electric motor" also includes the stator 9 of the electric motor 1, and the following explanation can also be applied to the core as the stator 9. Figure 2A is a radial cross-sectional view of the rotor shown in Figure 1, and Figure 2B is a partial axial cross-sectional view of the rotor along the line A-A' in Figure 2A. As can be seen from Figure 2A, the rotor 10 is annular, and a hole is formed in its center into which the shaft portion 5 (not shown in Figure 2A) is to be inserted. Also, as can be seen from Figure 2B, the rotor 10 is formed by stacking multiple magnetic plates (core plates) 11 of the same shape, such as iron plates, carbon steel plates, and electrical steel plates, in the axial direction of the rotor 10. In the first embodiment and some embodiments described later, the rotor 10 and stator 9 do not necessarily have to be formed from multiple magnetic plates 11, and the rotor 10 and stator 9 may be a single integrated component made from a magnetic material such as ferrite or a compacted iron core. Referring to Figure 2A, the rotor 10 has multiple pin holes 12 formed at equal intervals in the circumferential direction. As can be seen by referring to Figure 2B, each of the multiple magnetic plates 11 has (multiple) through holes formed therein. When the multiple magnetic plates 11 are stacked, the through holes align with each other to form the aforementioned pin holes 12. A pin 20 is inserted into each of the multiple pin holes 12 in the axial direction of the rotor 10. More precisely, the pins 20 are press-fitted into the corresponding pin holes 12 for the purpose of fastening adjacent magnetic plates 11 together. As can be seen from Figure 2B, the pin 20 may have a curved portion 21 that is at least partially curved in the axial direction. Such a curved portion 21 may come into contact with the inner wall of the pin hole 12, resulting in increased frictional resistance and making it difficult to press-fit the pin 20 into the pin hole 12. Therefore, in the first embodiment, a