JPH1198739A - Rotor steel plate for electric motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress as much as possible the buckling deformation in the axial direction generated at the time of insertion of shaft with pressure by arranging a bridge section on the diagonal line passing the reference point and inclined only by the predetermined angle for the reference line. SOLUTION: When a virtual circle 8 is drawn defining a rotor center as a central point 7 on an internal circumference area 3 and a crossing point between a reference line 9 passing the central point 7, and the virtual circle 8 is defined as the reference point 10, a tilting line 11 passing the reference point 10 and inclined by the predetermined angle θ against the reference line 9 is drawn and a bridge section 4 is arranged on the tilting line 11. When a shaft is inserted with pressure, the internal circumference area 3 indicated by an image line shifts toward the external side of diameter. Meanwhile, since an external circumference area 5 has sufficient rigidity, the bridge section 4 indicated by the imaginary line is deformed to curve along the same plane of the rotor steel plate. Basically, a bending force is applied to the bridge section 4. Since the bridge section 4 is formed like a narrow belt, it may be bent easily, and, when the external force is removed, it returns to the position of the imaginary line.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor steel plate for an electric motor having a window.

[0002]

2. Description of the Related Art FIG. 5 is an exploded view of a main portion of a typical electric motor. A rotating rotor 102 combined with a fixed stator 101 includes a shaft 103, a rotor steel plate 104,
The magnet 105 is composed of a magnet 105, a plurality of magnets, and a glass tape 106, and the rotor steel plate 104 is a thin magnetic steel plate, that is, a silicon steel plate. In the figure, the rotor steel plates 104 are stacked, and the shaft 103 is press-fitted therein.

FIG. 6 is a front view of a conventional rotor steel plate having a window shape. This rotor steel plate 110 has six windows 111... An inner peripheral portion 113 surrounding the inner periphery 112, six bridge portions 114 extending outward from the inner peripheral portion 113, and an outer peripheral portion 115 connecting the tips of these bridge portions 114.

[0004]

FIGS. 7A to 7C are diagrams showing the operation of a conventional rotor-plated steel plate having a window. (A)
, The shaft 103 is pressed into the rotor steel plate 110. Because of the press-fitting, the diameter of the shaft press-fitting hole 112 is smaller than the outer diameter of the shaft 103. Therefore, forces N, N directed radially outward act on the shaft press-fit hole 112 during press fit.
As is clear from FIG. 6, the bridge portions 114 are narrow bands. When a force N is applied, a compressive force acts on the bridge portions 114. When the compressive force exceeds a predetermined load, the bridge portions 114 Buckling deformation in the axial direction. (B) shows an example of the buckling deformation in the axial direction.
This indicates that only the curve deformation has occurred.

(C) shows another example of the buckling deformation in the axial direction.
The deformation of the bridge portions 114, 114 indicates that the outer peripheral portion 115 has been displaced by Δ in the axial direction with respect to the inner peripheral portion 113. When such deformation occurs, it is necessary to correct this deformation, and the processing cost rises. Therefore, an object of the present invention is to provide a structure in which axial buckling deformation generated at the time of press-fitting of a shaft can be suppressed as much as possible in a rotor steel plate having a window shape.

[0006]

To achieve the above object, the present invention provides an inner peripheral portion surrounding a shaft press-fitting hole, a plurality of bridge portions extending outward from the inner peripheral portion, and these bridge portions. Draw a virtual circle centered on the center of the rotor on the inner periphery of the rotor steel plate with a window that consists of the outer periphery connecting the tip of Then, an inclined line passing through the reference point and inclined by a predetermined angle with respect to the reference line is drawn, and the bridge portion is arranged on the inclined line. Since the bridge portion is inclined, the bridge portion can suppress generation of distortion in the axial direction. Therefore, there is no fear of buckling, and there is no fear of harmful axial buckling deformation.

The second aspect is characterized in that the predetermined angle is in the range of 30 ° to 90 °. When the angle is less than 30 °, a large compressive force component acts on the bridge portion, and the buckling becomes easy. If the angle exceeds 90 °, the width of the bridge cannot be secured. Therefore, the angle was in the range of 30 ° to 90 °.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a front view of an electric motor rotor steel plate according to the present invention. An electric motor rotor steel plate 1 (hereinafter abbreviated as “rotor steel plate 1”) has an inner peripheral portion 3 surrounding a shaft press-fitting hole 2. A plurality of bridge portions 4 extending outward from the inner peripheral portion 3;
And an outer peripheral portion 5 connecting the front ends of the windows.

FIG. 2 is an enlarged view of a main part of the rotor steel plate according to the present invention, in which an imaginary circle 8 having a center at the rotor center 7 is drawn on the inner peripheral portion 3, and a reference line 9 passing through the center 7 and an imaginary circle 8. When the intersection point of the circle 8 is set as the reference point 10, an inclined line 11 passing through the reference point 10 and inclined by a predetermined angle θ with respect to the reference line 9 is drawn, and the bridge portion 4 is arranged on the inclined line 11. It is characterized by having done. If the virtual circle 8 is within the width of the inner peripheral part 3,
You can draw anywhere.

The operation of the rotor steel plate having the above configuration will be described below. FIG. 3 is a modified explanatory view of the bridge portion according to the present invention. When a shaft (not shown) is press-fitted into the shaft press-fitting hole 2, the inner peripheral portion 3 shown by the imaginary line moves radially outward to the position of the solid line. On the other hand, since the outer peripheral portion 5 is sufficiently rigid, the bridge portions 4... Indicated by imaginary lines bend and deform on the same surface as the rotor steel plate 1 as indicated by solid lines. In addition, bending acts basically on the bridge portions 4. Bridge 4
Is a thin band, so it bends easily and returns to the position of the imaginary line when external force is removed. That is, even if a considerably large force acts, the bridge portion 4 is within the elastic limit, and buckling deformation does not occur in the axial direction.

If the press-fit load exceeds the limit and the bridge portions 4 buckle and deform in the axial direction, this deformation will occur on the surface of the rotor steel plate 1. That is, since there is no protrusion in the thickness direction of the rotor steel plate 1, there is little possibility that the lamination of the rotor steel plate 1 will be affected.

In FIG. 2, the inclination angle θ is approximately 90 °,
The force N due to the press-fit acts on the bridge portion 4 as a bending force. However, if the inclination angle θ is set to, for example, a half of 45 °,
Both the bending force component and the compressive force component act on the bridge portion 4, and the possibility of the buckling deformation of the bridge portion 4 increases. Therefore, the relationship between the inclination angle θ and the press-fit load was examined.

FIG. 4 is a graph showing the relationship between the inclination angle of the bridge portion and the press-fitting load according to the present invention.
The vertical axis indicates the buckling limit press-fit load. The inclination angle θ is 30 ° to 9
In the range of 0 °, the bridge does not buckle to a considerably large press-fit load. On the other hand, when θ falls below 30 °, the limit press-fitting load decreases. When θ exceeds 90 °, the width of the base 4a of the bridge portion 4 cannot be secured in FIG. Therefore, the inclination angle θ of the bridge portion 4 may be selected from the range of 30 ° to 90 °.

In the embodiment, the number is six, but the number of the bridge portions 4 is arbitrary.

[0015]

According to the present invention, the following effects are exhibited by the above configuration. In the first aspect, since the bridge portion is inclined, axial distortion due to shaft press-fitting can be relieved. Therefore, there is no fear of buckling and no risk of harmful buckling deformation in the axial direction.

A second aspect is characterized in that the predetermined angle is in a range of 30 ° to 90 °. When the angle is less than 30 °, a large compressive force component acts on the bridge portion, and the buckling becomes easy. If the angle exceeds 90 °, the width of the bridge cannot be secured. Therefore, the angle was in the range of 30 ° to 90 °.

[Brief description of the drawings]

FIG. 1 is a front view of a rotor steel plate for an electric motor according to the present invention.

FIG. 2 is an enlarged view of a main part of a rotor steel sheet according to the present invention.

FIG. 3 is an explanatory view showing a modification of a bridge section according to the present invention.

FIG. 4 is a graph showing the relationship between the inclination angle of the bridge portion and the press-fit load according to the present invention.

FIG. 5 is an exploded view of a main part of a typical electric motor.

FIG. 6 is a front view of a conventional window-shaped rotor steel plate.

FIG. 7 is an operation diagram of a conventional window-shaped rotor steel plate.

[Explanation of symbols]

1 ... rotor steel plate for electric motor 2 ... shaft press-fit hole
3 ... inner peripheral part, 4 ... bridge part, 5 ... outer peripheral part, 6 ... window, 7
... Center point, 8 ... Virtual circle, 9 ... Reference line, 10 ... Reference point, 1
1: slope line, θ: predetermined angle (inclination angle).

Claims (2)

[Claims] 1. A window-shaped rotor comprising: an inner peripheral portion surrounding a shaft press-fitting hole; a plurality of bridge portions extending outward from the inner peripheral portion; and an outer peripheral portion connecting ends of these bridge portions. On a steel plate, a virtual circle centered on the center of the rotor is drawn on the inner peripheral portion, and when an intersection of a reference line passing through the center point and the virtual circle is used as a reference point, the reference line passes through this reference point. A rotor steel plate for an electric motor, characterized in that an inclined line inclined by a predetermined angle is drawn with respect to the above, and the bridge portion is arranged on the inclined line. 2. The rotor steel plate for an electric motor according to claim 1, wherein the predetermined angle is in a range of 30 ° to 90 °.