JP2015139227A - motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique being capable of corresponding to a complicated skew structure without the need of a plurality of kinds of laminated steel plates while proposing a new structure being substituted for a key structure for preventing rotation of a rotor core with respect to a shaft.SOLUTION: A motor comprises: a rotor core 3 laminated with a plurality of laminated steel plates 9; a shaft 4 passing through the rotor core 3; and fixing members 8 fixing the rotor core 3 to the shaft 4 in an axial direction. The shaft 4 is inserted into a through-hole 9b provided in the laminated steel plates 9. A plurality of grooves 14 extending in a circumferential direction and having V-shapes is provided side-by-side in an axial direction on an outer peripheral surface of the shaft 4. The laminated steel plates 9 are press-fitted to the shaft 4. The other side surfaces of the grooves 14 are brought into contact with laminated steel plate end surfaces of a circumferential edge of the through-hole 9b while one side surfaces of the grooves 14 are brought into contact with a through-hole inner peripheral surface of the laminated steel plates 9.

Description

  The technology disclosed in this specification relates to a motor. In particular, the present invention relates to a synchronous motor in which a rotor core is provided with a permanent magnet.

  Generally, a synchronous motor includes a stator around which a coil is wound, a rotor core disposed inside the stator, and a shaft that passes through the rotor core and is rotatably supported. The permanent magnets provided in the rotor core are arranged at equal intervals in the circumferential direction when viewed from the rotation axis direction. Generally, the rotor core is configured by laminating a plurality of laminated steel plates. Further, the rotor core is prevented from rotating relative to the shaft. Typically, as a structure for preventing the rotation, a structure in which a key provided on a laminated steel sheet is fitted into a key groove provided on a shaft is known.

  On the other hand, conventionally, a skew structure is known as a structure for reducing torque ripple which is one of the causes of vibration in a synchronous motor. Here, the skew structure is a structure in which the permanent magnet inserted through the rotor core is arranged so as to be inclined with respect to the rotation axis of the motor. For example, a permanent magnet skew structure is realized in a motor having a structure for preventing rotation by the key groove and the key. In this case, the skew structure is realized by laminating a plurality of types of laminated steel plates in which the positions of the holes through which the permanent magnets are inserted (the positions of the holes with respect to the keys) are slightly shifted in the circumferential direction. According to this configuration, the types of laminated steel sheets increase and the number of parts increases.

  Patent Document 1 discloses a skew structure that is simplified by dividing the rotor core into two parts in the axial direction and arranging the divided rotor cores to be twisted in the axial direction. Furthermore, the torsion of the divided rotor core is such that, when viewed from the axial direction, in the laminated steel sheet in which the position of the permanent magnet insertion hole is offset with respect to the straight line passing through the center and the key of the laminated steel sheet, one is face up and the other is Realized by attaching to the shaft face down. With this configuration, the rotor core can be twisted with laminated steel plates having the same shape. Therefore, an increase in the types of laminated steel sheets can be avoided.

Japanese Patent Laid-Open No. 11-18339

  However, in order to further suppress the vibration of the motor, the skew structure tends to be complicated. In that case, even if the technique of Patent Document 1 is used, a plurality of types of laminated steel sheets are required.

  Therefore, in the present specification, a new structure that replaces the key structure is provided as a structure that prevents relative rotation between the rotor core and the shaft. By adopting the anti-rotation structure disclosed in this specification, it is possible to cope with a complicated skew structure without requiring a plurality of types of laminated steel sheets.

  In the technology disclosed in this specification, a friction force is generated between the laminated steel plate and the shaft by press-fitting the shaft into the laminated steel plate, and the relative rotation of the laminated steel plate with respect to the shaft is performed using the friction force. To prevent. However, it is not a simple press-fitting, but a structure capable of increasing the frictional force in the rotational direction after the press-fitting by devising the structure of the shaft is provided. For this reason, in the motor which has a skew structure, the kind of the some laminated steel plate required by the key and the keyway can be reduced.

  The motor disclosed in this specification includes a rotor core in which a plurality of laminated steel plates are laminated, and a shaft that passes through the rotor core. The shaft is inserted into a through hole provided in the laminated steel plate. A plurality of grooves each having a V-shaped cross section extending in the circumferential direction are provided in the axial direction on the outer peripheral surface of the shaft. A laminated steel plate is press-fitted into the shaft, and one side surface of the groove is in contact with the inner peripheral surface of the through hole of the laminated steel plate, and the laminated steel plate on the other side surface of the groove and the peripheral edge of the through hole The end faces are touching. Note that “pressing the laminated steel sheet into the shaft” is as follows in detail. The diameter of the through hole through which the shaft of the laminated steel plate passes is smaller than the diameter of the shaft (more precisely, the diameter of the shaft at the bottom of the groove). And when a laminated steel plate is attached to a shaft, the periphery of a through-hole carries out an out-of-plane deformation so that the diameter of a through-hole may become a magnitude | size beyond the outer diameter of a shaft. This out-of-plane deformation is elastic deformation.

  The peripheral edge of the through hole of the laminated steel plate undergoes out-of-plane deformation during press fitting. The above configuration skillfully utilizes this out-of-plane deformation, and the V-shaped so that the laminated steel plate end face of the periphery of the through hole after deformation and the inner peripheral surface of the laminated steel plate (inner peripheral surface of the through hole) are in surface contact with the shaft. A groove is provided. According to this configuration, a vertical drag acts between the inner peripheral surface of the laminated steel sheet and the end face of the laminated steel sheet adjacent to the inner peripheral surface of the laminated steel sheet and the side surface of the groove due to the elastic force generated by the deformation of the periphery of the through hole during press-fitting. Therefore, a high frictional force is generated between the inner peripheral surface of the laminated steel sheet and the end face of the laminated steel sheet and the side surface of the groove, thereby preventing relative rotation of the laminated steel sheet with respect to the shaft. Furthermore, since the through hole has a circular shape, a rotor core having an arbitrary skew structure can be obtained by twisting and laminating laminated steel plates having the same shape at a predetermined angle and attaching them to the shaft.

  Moreover, the fixing member which fixes said rotor core to a shaft in an axial direction may be further provided. The fixing member is, for example, a nut. According to such a configuration, an axial force acts on the rotor core from the fixing member in the axial direction, and the inner peripheral surface (the inner peripheral surface of the through hole) of the laminated steel plate and the side surface of the laminated steel plate end surface and the shaft groove constituting the rotor core. The vertical drag acting between the two increases further. Therefore, the frictional force acting between the inner peripheral surface of the laminated steel plate and the end surface of the laminated steel plate and the side surface of the groove is further increased. The effect of preventing rotation relative to the shaft of the laminated steel sheet can be further enhanced.

  According to the technology disclosed in this specification, in a motor having a skew structure, it is possible to reduce the types of a plurality of laminated steel plates that are required by a key and a key groove. Details and further improvements of the technology disclosed in this specification will be described in the following “DETAILED DESCRIPTION”.

It is typical sectional drawing seen from the direction perpendicular | vertical to the rotating shaft of the motor of an Example. It is a front view of the shaft with which the motor of an Example is equipped. It is the top view seen from the rotating shaft direction of the laminated steel plate with which the motor of an Example is equipped. It is an enlarged view of the area | region of the dashed-dotted line IV of FIG. It is the top view seen from the rotating shaft direction of the laminated steel plate with which the motor of another Example is equipped. It is sectional drawing of the laminated steel plate in the VI-VI line of FIG.

  The motor 2 according to the embodiment will be described with reference to the drawings. The motor 2 includes a rotor 5 and a stator 6, which are accommodated in a case 12. In FIG. 1, it should be noted that the hatching indicating the cross section of the rotor core 3 is omitted for easy viewing of the drawing. Further, the Z axis coincides with the axis CL of the rotor 5 (the rotation axis of the motor 2).

  The structure of the rotor 5 will be described. The rotor 5 includes a rotor core 3 and a shaft 4. The rotor core 3 has a cylindrical shape, and a through hole (rotor through hole 3b) is provided in a direction along the axis. The shaft 4 is inserted into the rotor through-hole 3b so that both ends thereof extend from both ends of the rotor core 3 in the axial direction (Z-axis direction). The shaft 4 is rotatably supported by the case 12 via a bearing 13 provided in the case 12, and the rotor core 3 is located inside the stator 6.

  The shaft 4 will be described. As shown in FIG. 2, the shaft 4 is provided with a V-shaped groove 14 extending in the circumferential direction on the outer peripheral surface thereof. The V-shaped groove 14 is a groove having a V-shaped cross section perpendicular to the extending direction of the groove. The V-shaped groove 14 is composed of one side surface 14a and the other side surface 14b. One side surface 14a is closer to a plane perpendicular to the axis CL of the shaft than the other side surface 14b. In other words, the angle formed between the shaft axis CL and the one side surface 14a is larger than the angle formed between the shaft axis CL and the other side surface 14b. The shaft axis CL is the same as the axis of the rotor 5 described above. Also, the width between the side surfaces of the one side surface 14a and the other side surface 14b becomes narrower toward the depth direction of the groove, and is in contact with the deepest portion of the groove. Further, a plurality of grooves 14 are arranged at equal intervals in the axial direction (Z-axis direction), and the side surface 14b of one groove 14 and the side surface 14a of the other groove 14 are connected. It should be noted that FIG. 2 is drawn with a part of the shape omitted in the axial direction.

  The rotor core 3 will be described. As shown in FIG. 1, the rotor core 3 is configured by laminating a plurality of laminated steel plates 9. The rotor core 3 is provided with washers 7a and 7b on both end faces in the axial direction (Z-axis direction), and is fixed in the axial direction by nuts 8 from the outside of the washers 7a and 7b. The nut 8 is fastened to the shaft 4, and the rotor core 3 is fixed to the shaft 4 by the axial force generated by the fastening. In addition, the washer 7b is provided with a recess in the surface in contact with the end face of the rotor core 3 in accordance with the shape of the laminated steel plate 9 that is deformed out of plane, which will be described later.

  The laminated steel sheet 9 will be described. As shown in FIG. 3, the laminated steel plate 9 is a circular flat plate. A pair of magnet mounting holes 16 are provided on the outer peripheral edge of the laminated steel plate 9. Eight pairs of magnet mounting holes 16 are arranged at equal intervals in the circumferential direction. By laminating the laminated steel plates 9, the magnet mounting holes 9 are connected, and the permanent magnets are accommodated therein. A through hole 9 b is provided at the center of the laminated steel sheet 9. By laminating the laminated steel plates 9, the through holes 9b communicate with each other to form the rotor through holes 3b. In addition, the diameter of the through hole 9 b is slightly smaller than the diameter of the bottom of the groove 14 of the shaft 4.

  The laminated steel sheet 9 is press-fitted from the end face of the shaft 4 in the negative Z-axis direction. When press-fitting, the peripheral edge of the through hole 9b of the laminated steel sheet 9 is deformed out of plane so as to be larger than the outer diameter of the shaft 4. When the laminated steel sheet 9 reaches the groove 14, the out-of-plane deformation of the peripheral edge of the through hole 9 b returns to the original state, and the inner peripheral surface of the through hole 9 b enters the groove 14. The out-of-plane deformation described above is repeated until the laminated steel sheet 9 is locked by the groove 14 at a predetermined position. FIG. 4 shows the positional relationship between the through hole 9b of the press-fitted laminated steel sheet 9 and the groove 14 of the shaft 4. The inner peripheral surface 9 c of the through hole 9 b is in contact with the side surface 14 b of the groove 14. Further, an end surface 9 a (laminated steel plate end surface) adjacent to the inner peripheral surface 9 c of the through hole 9 b is in contact with the other side surface 14 a of the groove 14. Here, before press-fitting into the shaft 4, the inner peripheral surface 9c of the through hole 9b is parallel to the central axis of the through hole 9b. In the press-fitted state, the peripheral edge of the through hole 9b is deformed out of plane according to the angle with the axis CL of the side surface 14b of the groove 14. Therefore, the elastic force from the inner peripheral surface 9b of the through hole 9b and the laminated steel plate end surface 9a acts on the side surfaces 14b, 14a of the groove 14.

  According to such a configuration, a vertical drag acts between the side surface 14b of the groove 14 and the inner peripheral surface 9c of the through hole 9b, and between the side surface 14a of the groove 14 and the laminated steel plate end surface 9a. By this vertical drag, a frictional force acts on both the side surface 14b of the groove 14 and the inner peripheral surface 9c of the through hole 9b and between the side surface 14a of the groove 14 and the laminated steel plate end surface 9a. The laminated steel sheet 9 is prevented from rotating with respect to the shaft 4 by these two frictional forces. Moreover, the axial force from the nut 8 fastened to both ends of the rotor core 3 acts in the axial direction (Z-axis direction). The axial force acts on each side surface of the groove 14 from the inner peripheral surface 9 b of the through hole 9 b and the laminated steel plate end surface 9 a of the laminated steel plate 9. Due to this axial force, the vertical drag between the side surfaces of the groove 14 and the through hole 9a is further increased, and thus the frictional force between the side surfaces of the groove 14 and the through hole 9a is further increased. Therefore, the rotor core 3 is more firmly fixed to the shaft 4 and its rotation is prevented.

  Moreover, since the through-hole 9b of the laminated steel plate 9 and the cross-sectional shape of the shaft 4 are both circular, the laminated steel plate 9 can be fixed to the shaft 4 in an arbitrary circumferential direction. Therefore, the rotor core 3 can be skewed by laminating the laminated steel plates 9 so as to be gradually twisted about the axis of the shaft 4. Therefore, an arbitrary skew structure of the rotor core 3 can be realized by the laminated steel plates 9 having the same shape. In the figure, the illustration of magnets arranged spirally with respect to the axis CL due to the skew structure is omitted.

  Another embodiment will be described. 5 and 6 show a laminated steel sheet 109 employed in this embodiment. The motor of this embodiment is the same as the above-described embodiment except for the laminated steel sheet 109. The laminated steel plate 109 is a circular flat plate. A pair of magnet mounting holes 116 are provided on the outer peripheral edge of the laminated steel plate 109, similarly to the laminated steel plate 9. A through hole 109 b is provided at the center of the laminated steel plate 109. The peripheral edge of the through hole 109b is bent toward the out of plane of the laminated steel plate 109. In other words, the central portion of the laminated steel plate 109b is raised in a circular shape, and a through hole 109b is provided at the center of the raised portion. Around the through hole 109b, four notches 115 are provided at equal intervals in the circumferential direction. The bending angle of the peripheral edge of the through hole 109b is designed according to the angle of the side surface 14a of the groove 14 provided in the shaft 4 with respect to the axis CL. Here, the bending angle of the peripheral edge of the through hole 109b is slightly shallower than the angle of the groove 14 with respect to the axis CL. That is, the diameter of the through hole 9 b is slightly smaller than the diameter of the bottom of the groove 14. When the laminated steel plate 109 is press-fitted into the shaft 4, the inner peripheral surface 109 c of the through hole 109 b comes into contact with one side surface 14 b of the groove 14. And the laminated steel plate end surface 109a adjacent to the inner peripheral surface 109c is in contact with the other side surface 14a of the groove 14. Accordingly, the positional relationship is the same as that of the above-described embodiment shown in FIG. 4, and the laminated steel sheet 109 is prevented from rotating with respect to the shaft 4.

  According to such a configuration, the peripheral edge of the through hole 109b is deformed in advance in accordance with the shape of the groove 14, and the notch 115 is provided, so that the peripheral edge of the through hole 109b is deformed in the out-of-plane direction. It becomes easy to do. Therefore, the laminated steel plate 109 is easily press-fitted into the shaft 4.

  Hereinafter, points to be noted regarding the technology shown in the embodiments will be described. In the above embodiment, the nut is used for fixing the rotor core in the axial direction, but other members may be used. For example, a press-fitting member that press-fits the shaft and sandwiches the rotor core may be used. That is, any member having a function of fixing the rotor core to the shaft in the axial direction may be used. The “nut 8” in this embodiment is an example of the “fixing member”.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

2: Motor 3: Rotor core 4: Shaft 5: Rotor 6: Stator 7a, 7b: Washer 8: Nut 9: Laminated steel plate 14: Groove

Claims (1)

A rotor core in which a plurality of laminated steel plates are laminated;
A shaft passing through the rotor core;
A fixing member for fixing the rotor core to the shaft in the axial direction,
The shaft is inserted into a through hole provided in the laminated steel plate,
On the outer peripheral surface of the shaft, a plurality of V-shaped grooves extending in the circumferential direction are provided side by side in the axial direction.
The laminated steel plate is press-fitted into the shaft, and one side surface of the groove is in contact with the inner peripheral surface of the through hole of the laminated steel plate, and the end surface of the laminated steel plate on the other side surface of the groove and the peripheral edge of the through hole Is touching,
A motor characterized by that.

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