JP6309876B2 - Magnet holder and motor using the same - Google Patents

Description

  The present invention relates to a magnet holder and a motor using the same, and more particularly to a magnet holder attached to a shaft of a motor so that the shaft penetrates and a motor using the magnet holder.

  As a method for detecting the rotational speed and rotational position of a motor, a method is known in which a magnet is fixed to a shaft and a change in a magnetic field by the magnet is detected by a sensor installed around the magnet.

  As a structure for fixing a magnet to a shaft, for example, the following is known.

  FIG. 6 is a view showing a conventional magnet fixing structure of the shaft.

  For example, as shown in FIG. 6A, there is a fixing structure 810 by pressing the shaft directly into a so-called plastic magnet (bonded magnet). That is, in this fixed structure 810, the magnet 880 is attached to the shaft 802 by press-fitting the shaft 802 directly into a magnet 880 which is a so-called plastic mug.

  Such a fixing structure 810 is excellent in cost because a relatively inexpensive magnet 880 can be used. However, since the stress generated in the magnet 880 becomes relatively large due to the press-fitting of the shaft 802, the magnet 880 may break. In order to prevent this, if the tightening margin between the magnet 880 and the shaft 802 is reduced, there is a problem that a problem arises in the holding strength (reliability) between the magnet 880 and the shaft 802.

  As shown in FIG. 6B, there is a fixing structure 820 in which a magnet and a metal bush are integrally formed by insert molding. In this fixed structure 820, a magnet 881 and a metal bush 891 inside which a shaft 802 is press-fitted are integrally formed.

  In such a fixing structure 820, since a large stress is not generated in the magnet 881, high reliability can be ensured. However, in terms of cost, the metal bush 891 and the magnet 881 need to be formed integrally, and a device for holding the magnet 881 (knurling or the like) is also required on the metal bush 891 side. There is a problem.

  As shown in FIG. 6C, there is a fixing structure 830 by two-color molding of a resin bush and a plastic mug. In this fixing structure 830, a magnet 882 which is a plastic magnet and a resin bush 892 below which a shaft 802 is press-fitted are integrally formed by two-color molding.

  Even in such a fixing structure 830, as in the fixing structure 820, a large stress is not generated in the magnet 882, so that high reliability can be ensured. However, it is necessary to mold the resin bushing 892 and the magnet 882 in two colors, and it is necessary to devise the shape for holding the magnet 882, the molding conditions, and the like. There is.

  In addition, there is a fixing structure (not shown) in which a magnet is combined with a metal bush and fixed by caulking. However, since a large number of processing steps are required for manufacturing the metal bush, and a relatively complicated process for caulking and fixing to the magnet is required, the number of steps increases and there is a problem in terms of cost.

  Patent Document 1 discloses a structure in which a magnet holder is fitted to a magnet by snap fit, the shaft is passed through the magnet holder in this state, and the magnet is fixed to the shaft.

JP 2010-35411 A

  However, the structure of Patent Document 1 is such that a protrusion of a snap fit protrudes from the magnet in the longitudinal direction (axial direction) of the shaft. Therefore, the motor becomes longer in the axial direction when incorporated in the motor. In addition, when adopting a structure in which a sensor is attached at a position separated in the axial direction, there is a problem that the distance between the magnet and the sensor needs to be secured large because of the protrusion of the protruding portion, resulting in poor sensor efficiency. .

  The present invention has been made to solve such problems, and provides a magnet holder that can securely attach a magnet to a shaft in a small space and has a low manufacturing cost, and a motor using the magnet holder. It is an object.

In order to achieve the above object, according to one aspect of the present invention, the magnet holder attached so that the shaft penetrates the shaft of the motor is in contact with the magnet having a through-hole through which the shaft penetrates vertically and the lower part of the magnet. The magnet has a plurality of recesses formed so as to be separated from each other in the circumferential direction so as to be recessed outward from the inner peripheral surface of the through hole. , Each of which has a plurality of claw portions protruding upward so as to be fitted in the through holes, a protrusion portion protruding toward the outside of the bush and fitting into the recess at the tip portion of the claw portion, and toward the inside of the bush A projecting abutment portion, and the bush is attached to the magnet so that the projecting portions of the plurality of claw portions fit into the recesses. In the state, the shaft is attached to the shaft so as claw portion is bent by abutting the respective abutment portions of the plurality of claw portions, between the the protrusion arms, inclined surfaces are formed, The inclined surface comes into contact with the vicinity of the concave portion of the magnet in a state where the claw portion is bent by the contact portion coming into contact with the shaft .
According to another aspect of the present invention, the magnet holder attached so that the shaft penetrates the shaft of the motor is in contact with the magnet having a through-hole through which the shaft penetrates up and down, and holds the magnet. The magnet has a plurality of recesses that are recessed outward from the inner peripheral surface of the through hole and spaced apart from each other in the circumferential direction, and the bush protrudes upward and fits into the through hole. It has a claw part, and the claw part is provided at the tip part of the arm part that extends upward, the tip part of the arm part that projects toward the outside of the magnet holder, and the tip part of the arm part. And a contact portion that protrudes toward the inside of the magnet holder, and each protrusion portion of the plurality of claw portions fits into the recess so that the bush is attached to the magnet. In this state, the shaft is attached to the shaft so that the arm is bent by abutting against each abutment portion of the plurality of claw portions, and in the state where the shaft is attached to the shaft, the claw portion is below the upper end portion of the magnet. is there.
Preferably, an inclined surface is formed between the arm portion and the projecting portion, and the inclined surface is in the vicinity of the concave portion of the magnet in a state where the claw portion is bent by the contact portion contacting the shaft. To touch.

  Preferably, the bush has a hole through which the shaft passes, and the inner diameter of the hole is set so that the shaft is press-fitted into the hole.

  Preferably, the plurality of recesses are formed at the upper end of the through hole of the magnet.

  Preferably, a C chamfered portion, a tapered portion, or an R chamfered portion is formed at the lower end portion of the through hole.

  Preferably, the bush is formed using a thermoplastic resin or a non-ferrous metal.

  According to another aspect of the present invention, a motor includes a shaft on which the magnet holder described above is attached, and a sensor that detects a change in a magnetic field due to rotation of the magnet as the shaft rotates.

  According to these inventions, the shaft abuts against the abutment portions of the plurality of claw portions in a state where the bush is attached to the magnet so that the projections of the plurality of claw portions are fitted in the recesses. The claw is bent and attached to the shaft. Therefore, the magnet can be securely attached to the shaft in a space-saving manner, and a magnet holder having a low manufacturing cost and a motor using the magnet holder can be provided.

It is sectional drawing which shows the motor in one of embodiment of this invention. It is a top view which shows a magnet holder. It is the sectional view on the AA line of FIG. It is a figure explaining the attachment method to the shaft of a magnet holder. It is a top view which shows the magnet holder which concerns on the modified example of this Embodiment. It is a figure which shows the magnet fixing structure of the conventional shaft.

  Hereinafter, a motor according to one embodiment of the present invention will be described.

  [Embodiment]

  FIG. 1 is a cross-sectional view showing a motor 1 according to one embodiment of the present invention.

  The motor 1 is a so-called DC motor. The motor 1 roughly includes a frame assembly 1a and an amateur assembly 1b that is rotatably supported with respect to the frame assembly 1a.

  The amateur assembly 1b includes a shaft (rotating shaft) 2, an armature portion 4, a commutator portion 6, a magnet holder 100, and the like. The amateur part 4 is attached to the shaft 2 by press fitting or the like. The amateur part 4 has an amateur core 5 having a plurality of salient poles projecting in the radial direction, and a coil 5b wound around each salient pole. The commutator 6 is provided near one end of the shaft 2. The commutator unit 6 has a commutator formed of a plurality of commutator pieces, and is connected to the coil 5 b of the armature unit 4. The commutator contacts a brush (not shown) provided on the bracket 30 of the frame assembly 1a.

  The magnet holder 100 is attached to the upper part of the shaft 2 so that the shaft 2 penetrates up and down. The magnet holder 100 includes a magnet 80 and a bush 90. The bush 90 is attached so as to contact the lower part of the magnet 80 and holds the magnet 80.

  The magnet 80 is, for example, a bonded magnet. The bush 90 is formed using a thermoplastic resin. The magnet 80 may be another type of magnet. The bush 90 may be formed using a non-ferrous metal.

  The frame assembly 1a is roughly divided into a portion on the motor case 10 side and a portion on the cover 60 attached to the end portion (upper end portion in FIG. 1) of the motor case 10.

  The part of the frame assembly 1a on the motor case side 10 is composed of a bracket 30, a plate 40, a driving magnet 50, and the like.

  The motor case 10 has a cylindrical shape that is closed so that the shaft 2 protrudes from one end portion (the lower end portion in FIG. 1) of the motor case 10. The opening of the other end portion (upper end portion in FIG. 1) of the motor case 10 is closed by the plate 40 via the bracket 30. A magnet 50 is disposed on the inner peripheral surface of the motor case 10. Bearings 21 and 22 are held at the center of one end of the motor case 10 and the center of the plate 40, respectively. The shaft 2 of the amateur assembly 1b is rotatably supported with respect to the frame assembly 1a by two bearings 21 and 22.

  The bracket 30 holds a brush. The brush is in contact with the commutator.

  A circuit board 70 is disposed on the cover 60 side of the frame assembly 1a. The circuit board 70 is disposed so that the shaft 2 passes therethrough. A power supply terminal and a sensor 70a are connected to the circuit board 70. A power supply line to the motor 1 is connected to the power supply terminal. The power supply terminal is a terminal that receives a current supplied to the motor 1 and is connected to the brush so as to be energized. Thereby, the current from the power supply terminal is sent to the commutator through the brush, and the motor 1 is driven.

  The sensor 70 a is disposed on the circuit board 70 so as to be close to the magnet 80 attached to the shaft 2 in the magnet holder 100. The sensor 70a detects a change in the magnetic field due to the rotation of the magnet 80 together with the shaft 2 when the motor 1 is driven. Based on the detection result, the rotational speed of the motor 1 can be calculated, and the drive control of the motor 1 can be performed.

  FIG. 2 is a plan view showing the magnet holder 100.

  In FIG. 2, the figure which looked at the magnet holder 100 from upper direction is shown. A two-dot chain line indicates a state in which the shaft 2 is not press-fitted into the bush 90 as described later.

  The magnet 80 has a through hole 81 through which the shaft 2 passes vertically. Three recesses 85 (85a, 85b, 85c) are formed at the upper end portion of the inner peripheral surface of the through-hole 81 so as to be recessed outward (in a direction away from the central axis of the shaft 2). Is formed. Since each recess 85 is formed at the upper end, it can be said that each recess 85 is recessed downward from the upper surface of the magnet 80.

  The bush 90 has three claw portions 95 (95a, 95b, and 95c) positioned in the through holes 81, respectively. That is, the same number of the claw portions 95 as the number of the recesses 85 is provided. Each nail | claw part 95 is arrange | positioned in the position which fits into the recessed part 85. FIG.

  Here, the three concave portions 85 and the claw portions 95 are arranged so as to be separated from each other so as to be equally spaced around the shaft 2 (around the rotation axis of the motor 1).

  FIG. 3 is a cross-sectional view taken along line AA in FIG.

  As shown in FIG. 3, in the present embodiment, a chamfered portion 87 is formed at the lower end portion of the through hole 81 of the magnet 80. The chamfered portion 87 is, for example, a portion in which a so-called C chamfering is made on the lower end edge of the through hole 81 over the entire circumference.

  Each of the three recesses 85 is recessed from the inner peripheral surface of the through hole 1 as shown in FIG. 3. The upper part of the recess 85 opens upward.

  In the present embodiment, the outer diameter of the magnet 80 is larger than the outer diameter of the bush 90, but the present invention is not limited to this.

  The bush 90 has a disk shape in which a hole 91 through which the shaft 2 passes is formed in the center. The inner diameter of the hole 91 is set so that the shaft 2 is press-fitted into the hole 91. That is, the inner diameter dimension of the hole 91 is set to be the same as or slightly smaller than the outer diameter dimension of the shaft 2.

  The three claw portions 95 have the same shape as each other. Each claw portion 95 protrudes upward from the disk-shaped portion of the bush 90 so as to fit into the through hole 81. The protruding height of the claw portion 95 (the length from the disc-shaped portion to the tip portion) is set to be smaller than the thickness of the magnet 80.

  The claw portion 95 includes an arm portion 96 extending upward from the disk-shaped portion, a projecting portion 97 provided at the distal end portion of the arm portion 96, and an abutting portion 98 projecting toward the inside of the bush 90, that is, toward the shaft 2. have.

  The arm portion 96 is formed such that the distance from the axis of the shaft 2 to the inner end is the same as or slightly larger than the radius of the hole 91, and the distance from the shaft 2 to the outer end is small. The diameter of the through hole 81 is the same as or slightly smaller than the radius. The arm part 96 has flexibility.

  The protruding portion 97 protrudes from the upper end portion of the arm portion 96 toward the outside of the bush 90, that is, toward the recessed portion 85. The claw portion 95 is formed so that the protruding portion 97 fits into the recessed portion 85 in a state where the magnet holder 100 is attached to the shaft 2. In the present embodiment, when the bush 90 is in a natural state where it is not attached to the magnet 80, the protruding ends of the protruding portions 97 of the three claw portions 95 that are coaxial with the through hole 81 (coaxial with the shaft 2). The diameters of the cylindrical surfaces that are in contact with each other are configured to be larger than the diameter of the through hole 81.

  The contact portion 98 protrudes from the upper end portion of the arm portion 96 toward the inside of the bush 90, that is, toward the shaft 2. When the magnet holder 100 is attached to the shaft 2 and the abutment portion 98 is in contact with the shaft 2, the claw portion 95 displaces the upper end portion of the arm portion 96 toward the outside of the bush 90. Thus, the arm portion 96 is configured to be bent. That is, when the bush 90 is in a natural state where it is not attached to the magnet 80, the cylindrical surfaces of the three claw portions 95 that are coaxial with the through-hole 81 (coaxial with the shaft 2) are in contact with each other. The diameter is configured to be smaller than the outer diameter of the shaft 2.

  Here, in the present embodiment, a gentle inclined surface 99 is formed between the arm portion 96 and the protruding portion 97 at the tip portion of the claw portion 95. The inclined surface 99 is a surface that gradually protrudes outward from the portion near the tip of the arm portion 96 and is connected to the protruding portion 97.

  As shown in FIG. 3, in a state where the magnet holder 100 is attached to the shaft 2, the lower surface of the magnet 80 is in contact with the upper surface of the disk-shaped portion of the bush 90. Further, the protruding portion 97 is fitted into the recessed portion 85. When the contact portion 98 contacts the shaft 2, the arm portion 96 is bent, and the inclined surface 99 contacts the lower edge portion that connects the inner peripheral surface of the through hole 81 and the recess 85. doing.

  In this state, the abutting portion 98 abuts on the shaft 2 and the upper portion of the claw portion 95 is biased outward, whereby the inclined surface 99 is pressed against the edge portion. Therefore, the magnet 80 is biased downward, and the magnet 80 is pressed against the bush 90. Therefore, the magnet 80 is firmly held by the bush 90. The bush 90 is press-fitted into the shaft 2, and the contact portion 98 is pressed against the outer peripheral surface of the shaft 2. Therefore, the bush 90 is firmly attached to the shaft 2.

  In the present embodiment, the recess 85 is formed in the through hole 81, and the claw portion 95 does not protrude upward from the upper end surface of the magnet 80 in a state where the magnet holder 100 is attached to the shaft 2. . Therefore, the thickness of the entire magnet holder 100 in the vertical direction can be reduced to save space. By using the magnet holder 100, the motor can be reduced in size.

  Here, attaching the magnet holder 100 to the shaft 2 can be performed by the following steps. That is, the shaft 2 is press-fitted into the bush 90 in a state where the bush 90 is fitted to the magnet 80 so that the protruding portions 97 of the three claw portions 95 are fitted to the concave portions 85. The magnet holder 100 can be attached to the shaft 2 while the claw portions 95 are bent by the abutment portions 98 of the claw portions 95 being in contact with the shaft 2.

  FIG. 4 is a diagram for explaining a method of attaching the magnet holder 100 to the shaft 2.

  As shown in FIG. 4, from step S <b> 11 to step S <b> 13, first, a process of attaching the bush 90 to the magnet 80 is performed.

  In step S <b> 11, the magnet 80 is set on the bush 90 from above the bush 90 so that all the three claw portions 95 fit into the through-hole 81. At this time, since the chamfered portion 87 is formed at the lower end edge of the through hole 81 of the magnet 80, even if the position of the bush 90 with respect to the magnet 80 is slightly shifted and the upper end portion of the claw portion 95 contacts the chamfered portion 87. The claw portion 95 is guided by the chamfered portion 87 so as to fit into the through hole 81. Therefore, the bush 90 can be set with respect to the magnet 80 smoothly.

  In step S <b> 12, the magnet 80 is pushed into the bush 90. At this time, the side part of the protrusion part 97 of each nail | claw part 95 is slidably contacted with the inner surface of the through-hole 81, and the nail | claw part 95 bends so that a front-end | tip part may be displaced inside a little.

  In step S <b> 13, when the magnet 80 is further pushed into the bush 90, the magnet 80 comes into contact with the upper surface of the bush 90. At the same time, the height from the lower surface of the magnet 80 to the concave portion 85 coincides with the height from the upper surface of the disk-shaped portion of the bush 90 to the protruding portion 97, the deflection of the claw portion 95 returns to the original, and the protruding portion 97 becomes the concave portion. 85 is inserted.

  By performing the processing from step S11 to S13 in this way, the bush 90 is engaged with the magnet 80, and the magnet 80 is unlikely to fall off the bush 90. Therefore, the press-fitting work of the shaft 2 performed in subsequent steps S14 and S15 can be easily performed.

  In step S14, the bush 90 is pushed into the shaft 2 from above. The shaft 2 is press-fitted into the hole 91 of the bush 90.

  In step S15, the bush 90 is further pushed into the shaft 2. As a result, the abutting portion 98 is urged outward by contacting the outer peripheral surface of the shaft 2, and the protruding portion 97 and the inclined surface 99 are pushed toward the inner peripheral surface of the through hole 81 of the magnet 80. Since the protruding portion 97 is deeper and fits into the recess 85, the magnet 80 is less likely to come off from the bush 90. Further, since the inclined surface 99 is pressed against the lower edge portion of the recess 85, the magnet 80 is biased downward and is more firmly held by the bush 90.

  As described above, in the present embodiment, the magnet 80 can be firmly attached to the shaft 2 by combining the bush 90 and the magnet 80 which have a relatively simple shape and are separately formed. . Therefore, the manufacturing cost of components can be reduced and the manufacturing cost of the motor 1 can be reduced.

  When the bush 90 and the magnet 80 are combined, a mechanical engagement structure (patching stop structure) using the elastic force of the arm portion 96 of the claw portion 95 is used. Therefore, it is not necessary to use a complicated method such as integral molding, two-color molding, or caulking, and the number of manufacturing steps can be reduced and the manufacturing cost can be reduced.

  Since the shaft 2 is press-fitted into the bush 90, the stress generated in the magnet 80 is reduced. Therefore, occurrence of cracks in the magnet 80 can be prevented, and the reliability of the motor 1 can be increased.

  When the shaft 2 is press-fitted into the bush 90, the claw portion 95 of the bush 90 is displaced and biased, so that the position of the magnet 80 in the vertical direction (direction parallel to the longitudinal direction of the shaft 2) and the position in the rotational direction are Is retained. Since a force acts between the shaft 2, the bush 90, and the magnet 80, looseness and rattling are unlikely to occur, and the reliability of the motor 1 is increased.

  In order to prevent rotation of the magnet 80 with respect to the shaft 2, it is not necessary to adopt a special shape such as providing a flat portion in the through hole 81 of the magnet 80, so that the manufacturing cost can be reduced. In the structure in which the magnet is sandwiched between the front end locking portion and the rear end locking portion as described in Patent Document 1, the boss of the rear end locking portion is crushed in the axial direction by the front end locking portion. There is a possibility that loosening in the axial direction may occur. However, in the present embodiment, the magnet 80 is hardly loosened in the axial direction by using the above-described configuration.

  The bush 90 does not protrude upward from the upper end of the magnet 80. Therefore, since the substantially entire upper surface of the magnet 80 can be exposed and the sensor 70a can be brought close to the upper surface of the magnet 80, the detection accuracy by the sensor 70a can be improved.

  Note that the number of claw portions and recesses is not limited to three. For example, there may be two or more than four. The plurality of claw portions and the concave portions are preferably arranged at equal intervals in the circumferential direction around the axis of the shaft 2.

  FIG. 5 is a plan view showing a magnet holder according to a modified example of the present embodiment.

  FIG. 5A shows an example of the magnet holder 200 in which the claw portion 95 and the concave portion 85 are provided in two places.

  FIG. 5B shows an example of the magnet holder 300 in which the claw portions 95 and the concave portions 85 are provided at four locations.

  FIG. 5C shows an example of the magnet holder 400 in which the claw portion 95 and the recessed portion 85 are provided in six places.

  Thus, the number of the claw portions 95 and the recesses 85 can be set as appropriate, and in any case, the same effect as described above can be obtained.

  [Others]

  What is necessary is just to set suitably the depth of the recessed part of a magnet, and the magnitude | size of a nail | claw part so that a protrusion part may not protrude upwards from the upper end surface of a magnet.

  The lower end portion of the through hole of the magnet may not be provided with a chamfered portion, or may be chamfered differently from the above. For example, the taper shape which spreads as it approaches a lower end part may be provided, and R chamfering shape may be given. By providing such a chamfered portion, the claw portion can be easily fitted into the through hole.

  The bush may not be made of resin. For example, it can be formed using a nonferrous metal or the like that is not ferromagnetic and has a spring property.

  The concave portion of the magnet is not limited to the upper end portion of the through hole, but may be formed on the inner surface of the through hole.

  The number of the claw portions of the bush may be two or more and may be the same as or smaller than the number of the concave portions of the magnet. The bush may not be an annular one having a hole. For example, a part of the disk-shaped portion in the above-described embodiment may be opened in the radial direction. In addition, the hole of the bush may be larger than the diameter of the shaft. Even in this case, the magnet holding tool is formed by the contact portion of the claw portion being urged by the shaft and the protruding portion being fitted into the recess. The effect of fixing to the shaft can be obtained.

  The configuration of the motor is not limited to that of the above-described embodiment. The motor may not be a DC motor. As a magnet mounting structure that is used by being mounted on a motor shaft, the structure of the present embodiment or a structure that employs some of its characteristic points can be used.

  The above embodiment should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Motor 2 Shaft 10 Motor case 70a Sensor 80 Magnet 81 Through-hole 85 Concave part 87 Chamfer part 90 Bush 91 Hole part 95 Claw part 96 Arm part 97 Projection part 98 Contact part 99 Inclination surface 100,200,300,400 Magnet holder

Claims (8)

A magnet holder attached to the shaft of the motor so that the shaft penetrates,
A magnet having a through-hole through which the shaft passes vertically;
A bush mounted to contact the lower portion of the magnet, and holding the magnet;
The magnet has a plurality of recesses formed so as to be separated from each other in the circumferential direction so as to be recessed outward from the inner peripheral surface of the through hole,
Each of the bushes has a plurality of claw portions projecting upward so as to fit in the through holes,
The nail portion is
An arm that extends upward;
A protrusion provided at the tip of the arm, protruding toward the outside of the magnet holder and fitted into the recess;
Provided at the tip of the arm, and provided with a contact portion protruding toward the inside of the magnet holder;
The shaft abuts against each abutment portion of the plurality of claw portions in a state where the bush is attached to the magnet so that the protruding portions of the plurality of claw portions are fitted in the recesses. So that the arm is bent and attached to the shaft ,
An inclined surface is formed between the arm portion and the protruding portion,
A magnet holder , wherein the inclined surface is in contact with a portion in the vicinity of the concave portion of the magnet in a state where the claw portion is bent by the contact portion being in contact with the shaft . A magnet holder attached to the shaft of the motor so that the shaft penetrates,
A magnet having a through-hole through which the shaft passes vertically;
In contact with the bottom of the magnet, and a bushing for holding said magnet,
The magnet is viewed recess from the inner peripheral surface of each of the through holes on the outside, has a plurality of recesses in the circumferential direction are separated from each other,
The bush are each projected upward stuck in the through-hole has a write no more claws,
The nail portion is
An arm that extends upward;
A protrusion provided at the tip of the arm, protruding toward the outside of the magnet holder and fitted into the recess;
Provided at the tip of the arm, and provided with a contact portion protruding toward the inside of the magnet holder;
In a state where each of the projecting portions of the plurality of claw portions is the bush is attached to the magnet and fitting into the recess, said by the shaft comes into contact with the respective contact portions of the plurality of claw portions It is attached to the shaft so that the arm is bent ,
A magnet holder , wherein the claw portion is below an upper end portion of the magnet in a state of being attached to the shaft . Between the projecting portion and the arm portion is inclined surface is formed,
The magnet holder according to claim 2 , wherein the inclined surface is in contact with a portion near the concave portion of the magnet in a state where the claw portion is bent due to the contact portion being in contact with the shaft. The bush has a hole through which the shaft passes,
The inner diameter dimension of the said hole part is a magnet holder of any one of Claim 1 to 3 set so that the said shaft may be press-fitted in the said hole part. The magnet holder according to any one of claims 1 to 4, wherein the plurality of recesses are formed at an upper end portion of the through hole of the magnet. The magnet holder according to any one of claims 1 to 5 , wherein any one of a C chamfered portion, a tapered portion, and an R chamfered portion is formed at a lower end portion of the through hole. The magnet holder according to any one of claims 1 to 6 , wherein the bush is formed using a thermoplastic resin or a non-ferrous metal. A shaft to which the magnet holder according to any one of claims 1 to 7 is attached;
A motor having a sensor for detecting a change in a magnetic field caused by rotation of the magnet with rotation of the shaft.

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