JP2018133847A - Rotor and motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress reduction in detection accuracy of a magnetic flux by a detector.SOLUTION: A rotor 10 that constitutes a part of a motor 12, comprises a rotation shaft 24, and a magnet constituent 26 fixed to the rotation shaft 24. The magnet constituent 26 comprises: a rotor magnet part 28 arranged coaxially with the rotation shaft 24; and a sensor magnet part 30 arranged coaxially with the rotation shaft 24 and arranged at an interval in an axial direction of the rotation shaft 24 from the rotor magnet part 28, and whose magnetic flux B is detected by the detector 16. The magnet constituent 26 comprises a spacer part 32 provided between the rotor magnet part 28 and the sensor magnet part 30 and connecting the rotor magnet part 28 and the sensor magnet part 30 in the axial direction of the rotation shaft 24.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rotor and a motor.

  Patent Document 1 below discloses a rotor in which a rotor magnet and a sensor magnet are integrally formed. In this rotor, the magnetic pole of the rotor magnet and the magnetic pole of the sensor magnet coincide with each other in the circumferential direction. Therefore, compared to the case of using a separate rotor magnet and sensor magnet, the positional deviation of both magnetic poles due to assembly errors. Is unlikely to occur.

JP-A-2015-204638

  However, if the rotor magnet and the sensor magnet are close to each other, the detection accuracy of the detection unit (magnetic sensor such as Hall IC) that detects the magnetic flux of the sensor magnet may be reduced due to the influence of the magnetic field of the rotor magnet. is there.

  In view of the above fact, an object of the present invention is to obtain a rotor and a motor that can suppress a decrease in magnetic flux detection accuracy by a detection unit.

  The rotor according to claim 1 is a rotary shaft, a rotor magnet portion disposed coaxially with the rotational shaft, a shaft disposed coaxially with the rotational shaft, and spaced in the axial direction of the rotor magnet portion and the rotational shaft. A sensor magnet unit that is arranged with a gap and the magnetic flux is detected by the detection unit, and the rotor magnet unit and the sensor magnet unit that are provided between the rotor magnet unit and the sensor magnet unit are arranged on the axis of the rotation shaft. And a magnet component that is fixed to the rotating shaft.

  According to the rotor of the first aspect, the magnet structure is fixed to the rotating shaft. Here, in this magnet structure, the rotor magnet part and the sensor magnet part are connected via the spacer part. Therefore, when the magnet component is fixed to the rotation shaft, the sensor magnet unit is prevented or suppressed from being displaced with respect to the rotor magnet unit. Moreover, in this magnet structure, the rotor magnet part and the sensor magnet part are spaced apart in the axial direction via the spacer part. Thereby, the influence of the magnetic flux of a rotor magnet part on the detection part which detects the magnetic flux of a sensor magnet part can be made small. Thereby, it can suppress that the detection accuracy of the magnetic flux of the sensor magnet part by a detection part falls.

  The rotor according to claim 2 is the rotor according to claim 1, wherein at least one of the rotor magnet part and the sensor magnet part is formed using a bond magnet including a resin material and magnetic powder. .

  According to the rotor of the second aspect, at least one of the rotor magnet portion and the sensor magnet portion is formed using the bond magnet, so that the weight of the magnet structure can be reduced. Thereby, weight reduction of a rotor can be achieved.

  The rotor according to claim 3 is the rotor according to claim 1 or 2, wherein the outer diameter of the rotor magnet portion, the outer diameter of the spacer portion, and the outer diameter of the sensor magnet portion are the same. ing.

  According to the rotor of the third aspect, the outer diameter of the rotor magnet portion, the outer diameter of the spacer portion, and the outer diameter of the sensor magnet portion are set to the same outer diameter, thereby being generated in the spacer portion in the magnet structure. An increase in stress can be suppressed.

  The rotor according to claim 4 is the rotor according to claim 1 or 2, wherein the outer diameter of the spacer portion is smaller than the outer diameter of the rotor magnet portion and the outer diameter of the sensor magnet portion. ing.

  According to the rotor of the fourth aspect, the spacer portion is reduced in weight by the outer diameter of the spacer portion being smaller than the outer diameter of the rotor magnet portion and the outer diameter of the sensor magnet portion. Can do. Thereby, the weight reduction of a magnet structure can be achieved and the weight reduction of a rotor can be achieved.

  The motor according to claim 5 is rotated by a stator that generates a magnetic field, a magnetic field generated by the stator and a magnetic field of the rotor magnet unit, and the rotor according to any one of claims 1 to 4. And a detector for detecting the magnetic flux of the sensor magnet unit.

  According to the motor of the fifth aspect, the rotor magnet portion and the sensor magnet portion of the magnet structure are separated in the axial direction via the spacer portion. Thereby, the influence of the magnetic flux of a rotor magnet part on the detection part which detects the magnetic flux of a sensor magnet part can be made small. Thereby, it can suppress that the detection accuracy of the magnetic flux of the sensor magnet part by a detection part falls.

It is a sectional side view showing typically the motor provided with the rotor concerning a 1st embodiment. It is a sectional side view showing typically a motor provided with a rotor concerning a 2nd embodiment.

  A motor including a rotor according to a first embodiment of the present invention will be described with reference to FIG. In addition, the arrow Z direction, the arrow R direction, and the arrow C direction that are appropriately shown in the drawing indicate the rotation axis direction, the rotation radial direction, and the rotation circumferential direction of the rotation shaft (rotor) of the motor, respectively. In the following description, when only the axial direction, radial direction, and circumferential direction are indicated, the rotational axis direction, rotational radial direction, and rotational circumferential direction of the rotating shaft (rotor) are indicated unless otherwise specified.

  As shown in FIG. 1, the motor 12 including the rotor 10 according to the first embodiment is an inner rotor type brushless motor. The motor 12 includes a stator 14 that generates a rotating magnetic field, and rotation of the stator 14. A rotor 10 that rotates in response to a magnetic field and a detection unit 16 (such as a Hall IC) for detecting the rotation speed and rotation angle of the rotor 10 are provided.

  The stator 14 is formed by winding a winding around each tooth portion 18 and a stator core 20 that includes a plurality of tooth portions 18 that extend in the radial direction and are arranged at equal intervals in the circumferential direction. And a plurality of coil sections 22. The energization of the windings forming the coil portion 22 is switched so that a rotating magnetic field is generated around the stator 14.

  The rotor 10 is disposed on the radially inner side of the stator 14. The rotor 10 includes a rotating shaft 24 formed in a rod shape and a magnet component 26 fixed to the rotating shaft 24.

  The rotating shaft 24 is formed in a rod shape using a steel material or the like, and the rotating shaft 24 is rotatably supported via a bearing or the like (not shown).

  The magnet structure 26 is formed in a cylindrical shape with an axial intermediate portion constricted in a side view, and the magnet structure 26 is fixed to the rotating shaft 24 through insert molding, an adhesive, or the like.

  Specifically, one side in the axial direction (arrow Z direction side) of the magnet structure 26 is a rotor magnet portion 28 that is disposed to face the stator 14 in the radial direction. The rotor magnet portion 28 is formed in a cylindrical shape by being mixed with a magnetic powder and a resin material and then cooled after being injected into the mold. In the present embodiment, the N pole and the S pole are alternately magnetized along the circumferential direction of the rotor magnet portion 28 through the magnetizing process.

  The other side of the magnet structure 26 in the axial direction (the side opposite to the arrow Z direction) is disposed so as to face the detection unit 16 in the radial direction and is spaced apart from the rotor magnet unit 28 in the axial direction. Part 30. The sensor magnet unit 30 is formed in a cylindrical shape by injecting a mixed material of magnetic powder and a resin material into a mold and then cooling the same as the rotor magnet unit 28. In the present embodiment, the N pole and the S pole are alternately magnetized along the circumferential direction of the sensor magnet unit 30 through the magnetization process. In the present embodiment, the dimension D1 (diameter) in the radial direction of the sensor magnet part 30 is set to the same dimension as the dimension D1 (diameter) in the radial direction of the rotor magnet part 28, and the sensor magnet part The dimension L2 (length) in the axial direction of 30 is set to be smaller than the dimension L1 (length) in the axial direction of the rotor magnet part 28.

  An intermediate portion in the axial direction of the magnet structure 26 is a spacer portion 32 that connects the rotor magnet portion 28 and the sensor magnet portion 30 in the axial direction. The spacer portion 32 is formed using a resin material or the like and is not magnetic. In this embodiment, the dimension D2 (diameter) in the radial direction of the spacer portion 32 is set to be smaller than the dimension D1 (diameter) in the radial direction of the sensor magnet portion 30 and the rotor magnet portion 28. .

  Here, the variation of the manufacturing method of the magnet structure 26 is demonstrated. The magnet component 26 may be manufactured by separately molding the rotor magnet part 28 and the sensor magnet part 30 and then molding the rotor magnet part 28 and the sensor magnet part 30 together with the material forming the spacer part 32. . The rotor magnet portion 28 and the sensor magnet portion 30 may be formed using ceramics or the like instead of the bond magnet. In addition, the magnet component 26 is cooled by injecting a mixture of magnetic powder and resin material into the mold corresponding to the shape of the magnet component 26, and then the rotor magnet unit 28 and the sensor magnet unit 30 (spacer). You may manufacture by magnetizing the part except the part 32). Thus, the magnet structure 26 may be manufactured in other directions as long as the rotor magnet portion 28 and the sensor magnet portion 30 are connected via the spacer portion 32 in a state of being separated in the axial direction.

(Operation and effect of this embodiment)
Next, the operation and effect of this embodiment will be described.

  As shown in FIG. 1, according to the motor 12 having the rotor 10 of the present embodiment, when a coil portion 22 forming a part of the stator 14 is energized, a rotating magnetic field is generated around the stator 14. . The rotor 10 is rotated by the rotating magnetic field and the magnetic field of the rotor magnet portion 28 of the magnet structure 26. Further, when the rotor 10 rotates, the magnetic flux B between the sensor magnet unit 30 and the detection unit 16 of the magnet component 26 changes. Then, when the change of the magnetic flux B is detected by the detection unit 16, the rotation speed and rotation angle of the rotor 10 can be calculated.

  Here, in the magnet structure 26 that constitutes a part of the rotor 10 of the present embodiment, the rotor magnet portion 28 and the sensor magnet portion 30 are connected via the spacer portion 32. Therefore, when the magnet component 26 is fixed to the rotating shaft 24, the sensor magnet unit 30 is displaced with respect to the rotor magnet unit 28 (the phase in the circumferential direction between the sensor magnet unit 30 and the rotor magnet unit 28 changes). Is prevented or suppressed. Further, in the magnet configuration body 26, the rotor magnet portion 28 and the sensor magnet portion 30 are separated in the axial direction via the spacer portion 32. Thereby, the influence of the magnetic flux of the rotor magnet part 28 on the detection part 16 which detects the magnetic flux B of the sensor magnet part 30 can be reduced. Thereby, it can suppress that the detection accuracy of the magnetic flux of the sensor magnet part 30 by the detection part 16 falls.

  Moreover, in this embodiment, the rotor magnet part 28 and the sensor magnet part 30 are formed using the bond magnet, and the weight reduction of the magnet structure 26 can be achieved. Thereby, weight reduction of the rotor 10 can be achieved.

  Further, in the present embodiment, the dimension D2 in the radial direction of the spacer portion 32 is set to be smaller than the dimension D1 in the radial direction of the sensor magnet portion 30 and the rotor magnet portion 28. Thereby, weight reduction of the spacer part 32 can be achieved. As a result, the magnet structure 26 can be reduced in weight, and the rotor 10 can be reduced in weight.

(Rotor 34 according to the second embodiment)
Next, the rotor 34 according to the second embodiment of the present invention will be described. Note that in the rotor 34 according to the second embodiment, members and portions corresponding to the rotor 10 according to the first embodiment are denoted by the same reference numerals as those corresponding to the rotor 10 and description thereof is omitted. To do.

  FIG. 2 discloses a motor 36 including a rotor 34 according to the second embodiment. As shown in this figure, in the rotor 34 of this embodiment, the dimension D1 (diameter) in the radial direction of the magnet component 26 is set to the same dimension along the axial direction. That is, the dimension D1 in the radial direction of the rotor magnet part 28, the spacer part 32, and the sensor magnet part 30 of the magnet structure 26 is set to the same dimension.

  According to the rotor 34 according to the second embodiment described above, the dimension D1 in the radial direction of the rotor magnet part 28, the spacer part 32, and the sensor magnet part 30 of the magnet structure 26 is set to the same dimension. Further, it is possible to suppress an increase in stress generated in the spacer portion 32 in the magnet structure 26.

  In the first embodiment and the second embodiment, the example in which the detection unit 16 is arranged on the radially outer side of the sensor magnet unit 30 of the magnet structure 26 has been described. However, the present invention is not limited to this. For example, the detection unit 16 may be arranged on the other side in the axial direction of the sensor magnet unit 30 as indicated by a two-dot chain line in FIGS.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above, and various modifications other than the above can be implemented without departing from the spirit of the present invention. Of course.

DESCRIPTION OF SYMBOLS 10 Rotor 12 Motor 14 Stator 16 Detection part 24 Rotating shaft 26 Magnet structure 28 Rotor magnet part 30 Sensor magnet part 32 Spacer part 34 Rotor 36 Motor

Claims (5)

A rotation axis;
A rotor magnet unit disposed coaxially with the rotation shaft, and disposed coaxially with the rotation shaft and spaced in the axial direction of the rotor magnet unit and the rotation shaft, and detects a magnetic flux by the detection unit. A sensor magnet part, and a spacer part provided between the rotor magnet part and the sensor magnet part and connecting the rotor magnet part and the sensor magnet part in the axial direction of the rotation shaft, A magnet structure fixed to the rotating shaft;
With a rotor.   The rotor according to claim 1, wherein at least one of the rotor magnet part and the sensor magnet part is formed using a bond magnet configured to include a resin material and magnetic powder.   The rotor according to claim 1, wherein an outer diameter of the rotor magnet portion, an outer diameter of the spacer portion, and an outer diameter of the sensor magnet portion are the same outer diameter.   The rotor according to claim 1, wherein an outer diameter of the spacer portion is smaller than an outer diameter of the rotor magnet portion and an outer diameter of the sensor magnet portion. A stator that generates a magnetic field;
The rotor according to any one of claims 1 to 4, wherein the rotor is rotated by a magnetic field generated by the stator and a magnetic field of the rotor magnet unit.
The detection unit for detecting the magnetic flux of the sensor magnet unit;
With motor.