JP7130728B2 - ROTOR, BRUSHLESS MOTOR, ROTOR MANUFACTURING METHOD - Google Patents

Description

The present invention relates to a rotor, a brushless motor, and a rotor manufacturing method.

For example, Patent Document 1 discloses a brushless motor in which a rotor made of a permanent magnet rotates when a current is passed through a coil wound around a field core. An integrally mounted configuration on both end faces is described. The retainer is integrally attached to both end surfaces of the rotor by crimping both end portions of the sleeve to the end surfaces of the retainer inserted into the sleeve together with the cylindrical rotor.

Japanese Utility Model Laid-Open No. 62-119182

If there are large variations in the dimensions of the parts that make up the rotor, such as the rotating shaft, magnets, and the magnet case that covers the outer peripheral surface of the magnet, or assembly errors, the rotor will run out or be unbalanced, causing vibration. may become large. Immediately after the rotor is assembled, even if the amount of run-out and unbalance is small, especially when the rotor is rotated at high speed, deformation, breakage, misalignment, etc. of parts may occur as the rotor rotates, causing vibration. It may grow.
An object of the present invention is to provide a rotor or the like capable of suppressing vibration.

The present invention completed for the above object is a rotor rotatable about a predetermined center line, comprising: a columnar magnet; a magnet case covering at least a part of the outer peripheral surface of the magnet; and a cylindrical portion, wherein the cylindrical portion of the rotating shaft is a rotor that covers the outer peripheral surface of the end portion of the magnet case in the direction of the center line.
Here, the magnet case is press-fitted into the magnet, and has a concave portion on the outer peripheral surface of the end portion in the center line direction, which is recessed toward the center line side from the outer peripheral surface of the central portion. may be press-fitted into the recess.
Further, the outer peripheral surface of the concave portion of the magnet case and the inner peripheral surface of the cylindrical portion of the rotating shaft may be adhered.
Further, the end face of the magnet in the centerline direction and the end face of the rotation shaft in the centerline direction facing the end face may not be joined.
Further, the magnet case may have a case tubular portion that covers a part of the outer peripheral surface of the magnet, and a cover portion that covers an end surface of the magnet in the direction of the center line.
Moreover, the said cover part may have a through-hole.
From another point of view, the present invention is a brushless motor comprising a stator and the rotor rotatably provided inside the stator.
Viewed from another point of view, the present invention provides a method of manufacturing a rotor rotatable about a predetermined center line, wherein a columnar magnet is provided with a magnet case covering at least a portion of the outer peripheral surface of the magnet. a step of cutting the outer peripheral surface of the end portion of the magnet case in the center line direction to form a recess recessed from the outer peripheral surface of the central portion toward the center line side; and a step of relatively moving a rotating shaft having a shaft portion and a cylindrical portion in the direction of the center line and press-fitting the concave portion of the magnet case and the cylindrical portion of the rotating shaft. It is a manufacturing method of the rotor which has.
Here, in a state in which the magnet case is press-fitted into the magnet, a step of simultaneously cutting an end surface of the magnet on one side in the center line direction and an end surface of the magnet case on one side in the center line direction. may have.

ADVANTAGE OF THE INVENTION According to this invention, the rotor etc. which can suppress a vibration can be provided.

It is a figure which shows an example of the cross section of the brushless motor which concerns on 1st Embodiment. FIG. 3 is a perspective view showing an example of components that constitute the rotor according to the first embodiment; It is a figure which shows an example of the manufacturing method of the rotor which concerns on 1st Embodiment. It is a figure which shows an example of the cross section of the brushless motor which concerns on 2nd Embodiment. It is a figure which shows an example of the manufacturing method of the rotor which concerns on 2nd Embodiment.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings.
<First Embodiment>
FIG. 1 is a diagram showing an example of a cross section of a brushless motor 1 according to the first embodiment.
FIG. 2 is a perspective view showing an example of parts forming the rotor 10 according to the first embodiment.
A brushless motor 1 according to this embodiment includes a rotor 10 , a stator 20 , and a housing 30 that accommodates the stator 20 .

The rotor 10 has a rotating shaft 11 , a cylindrical magnet 12 , and a cylindrical magnet case 13 covering the outer peripheral surface of the magnet 12 . The magnet case 13 is press-fitted into the magnet 12 , and the rotating shaft 11 is press-fitted into the magnet case 13 . Below, the center line direction of the rotating shaft 11 may be simply called "axial direction." In addition, in the axial direction, the left side of FIG. 1 may be referred to as "one side" and the right side of FIG. 1 may be referred to as "the other side".
The rotor 10 will be detailed later.

The stator 20 includes a cylindrical coil 21 , a cylindrical stack 22 holding the coil 21 , a relay board 23 provided on the other end surface of the stack 22 , and lead wires 24 connected to the relay board 23 . and

The housing 30 includes a cylindrical case 31 that is open at both ends in the axial direction of the rotating shaft 11, a first plate 32 that covers the opening on one side of the case 31, and a second plate that covers the opening on the other side of the case 31. 33. Further, the housing 30 is held by the first plate 32 and includes a first bearing 34 that rotatably supports one end of the rotating shaft 11 and a rotatably supporting end of the rotating shaft 11 on the other side. A second bearing 35 is provided.
The first plate 32 and the second plate 33 are substantially cylindrical members that hold the first bearing 34 and the second bearing 35 inside, respectively, and are fitted inside the case 31 . It can be exemplified that the first bearing 34 and the second bearing 35 are ball bearings.

Further, the brushless motor 1 includes a detection device 50 provided on the other side of the second bearing 35 for detecting the rotation angle of the rotor 10, and a bottomed cylindrical cover 60 covering the detection device 50. there is
The detection device 50 has a magnetic sensor 51 , a sensor substrate 52 on which the magnetic sensor 51 is mounted, and a magnet unit 54 having a sensor magnet 53 provided to face the magnetic sensor 51 .

(Rotor 10)
The rotating shaft 11 has a first rotating shaft 70 press-fitted into one end of the magnet case 13 and a second rotating shaft 80 press-fitted into the other end of the magnet case 13 .
The first rotating shaft 70 has a columnar first cylindrical portion 71 provided on one side and a cylindrical first cylindrical portion 72 provided on the other side of the first columnar portion 71 . is doing. The first rotating shaft 70 also has a first connecting portion 73 that connects the first columnar portion 71 and the first cylindrical portion 72 .
The second rotating shaft 80 has a cylindrical second columnar portion 81 provided on the other side and a cylindrical second cylindrical portion 82 provided on one side of the second columnar portion 81 . is doing. The second rotating shaft 80 also has a second connecting portion 83 that connects the second columnar portion 81 and the second cylindrical portion 82 .

In the magnet case 13 , a first recess 911 recessed from a central outer peripheral surface 931 of the central portion 93 is formed at a first end portion 91 that is one end portion in the axial direction. In the magnet case 13 , a second recessed portion 921 recessed from the central outer peripheral surface 931 of the central portion 93 is formed at the second end portion 92 that is the end portion on the other side in the axial direction.
The magnet case 13 is formed by cutting a cylindrical material using a lathe to form the first concave portion 911 and the second concave portion 921 .

A first outer peripheral surface 913 of the first recess 911 is a surface parallel to the axial direction, and the diameter of the first outer peripheral surface 913 is smaller than the diameter of the central outer peripheral surface 931 of the central portion 93 . A second outer peripheral surface 923 of the second recess 921 is parallel to the axial direction, and the diameter of the second outer peripheral surface 923 is smaller than the diameter of the central outer peripheral surface 931 of the central portion 93 . It can be exemplified that the diameter of the first outer peripheral surface 913 of the first recess 911 and the diameter of the second outer peripheral surface 923 of the second recess 921 are the same.

The diameter of the outer peripheral surface of the first columnar portion 71 of the first rotating shaft 70 is smaller than the diameter of the first outer peripheral surface 913 of the first concave portion 911 of the magnet case 13 . Also, the diameter of the first inner peripheral surface 721 of the first cylindrical portion 72 of the first rotating shaft 70 is equal to the diameter of the first concave portion 911 of the magnet case 13 before the first cylindrical portion 72 is press-fitted into the magnet case 13 . is slightly smaller than the diameter of the first outer peripheral surface 913 of the . The first cylindrical portion 72 is fitted to the magnet case 13 by tight fit. However, the first cylindrical portion 72 may be fitted to the magnet case 13 with an intermediate fit. In the first rotating shaft 70, the first cylindrical portion 72 covers part of the first outer peripheral surface 913 of the first concave portion 911 of the magnet case 13, and the first end surface 731 of the first connecting portion 73 It is attached to the magnet case 13 so as to contact the first end face 122 of the magnet 12 and one end face of the magnet case 13 . The first end surface 731 of the first connecting portion 73 of the first rotating shaft 70 is not joined to the first end surface 122 of the magnet 12 and one end surface of the magnet case 13 by adhesion, adhesion, welding, or the like.

When the first rotating shaft 70 and the magnet case 13 are assembled, the first rotating shaft 70 and the magnet case 13 are axially aligned with the adhesive applied to the first outer peripheral surface 913 of the first concave portion 911 of the magnet case 13 . The magnet case 13 is relatively moved. For example, the first rotating shaft 70 is moved from one side in the axial direction to the other side with respect to the magnet case 13 . The adhesive intervenes between the first inner peripheral surface 721 of the first cylindrical portion 72 of the first rotating shaft 70 and the first outer peripheral surface 913 of the first concave portion 911 of the magnet case 13, The shaft 70 and the magnet case 13 are adhered. Also, part of the adhesive moves from one side to the other side in the axial direction as the first rotating shaft 70 and the magnet case 13 are moved relative to each other. It moves into the gap between the tip and one end of the central portion 93 . The adhesive that has moved into this gap is removed, for example, by wiping it off, if necessary.

The diameter of the outer peripheral surface of the second columnar portion 81 of the second rotating shaft 80 is smaller than the diameter of the second outer peripheral surface 923 of the second concave portion 921 of the magnet case 13 . In addition, the diameter of the second inner peripheral surface 821 of the second cylindrical portion 82 of the second rotating shaft 80 is equal to that of the second concave portion 921 of the magnet case 13 before the second cylindrical portion 82 is press-fitted into the magnet case 13 . is slightly smaller than the diameter of the second outer peripheral surface 923 of the . The second cylindrical portion 82 is fitted to the magnet case 13 by interference fit. However, the second cylindrical portion 82 may be fitted to the magnet case 13 with an intermediate fit. The second rotating shaft 80 is attached to the magnet case 13 so that the second cylindrical portion 82 partially covers the second outer peripheral surface 923 of the second concave portion 921 of the magnet case 13 . Then, the second end surface 831 of the second connecting portion 83 of the second rotating shaft 80 and the other end surface of the magnet case 13 are adhered, adhered, or adhered to the second end surface 123 of the magnet 12 and the other end surface of the magnet case 13 . Not joined by welding or the like.

When the second rotating shaft 80 and the magnet case 13 are assembled, the second rotating shaft 80 and the magnet case 13 are axially aligned with the adhesive applied to the second outer peripheral surface 923 of the second concave portion 921 of the magnet case 13 . The magnet case 13 is relatively moved. For example, the second rotating shaft 80 is moved from the other side in the axial direction to the one side with respect to the magnet case 13 . The adhesive intervenes between the second inner peripheral surface 821 of the second cylindrical portion 82 of the second rotating shaft 80 and the second outer peripheral surface 923 of the second concave portion 921 of the magnet case 13, The shaft 80 and the magnet case 13 are adhered. Also, part of the adhesive moves from the other side to the one side in the axial direction as the second rotating shaft 80 and the magnet case 13 are moved relative to each other. It moves into the gap between the tip and the other end of the central portion 93 . The adhesive that has moved into this gap is removed, for example, by wiping it off, if necessary.

The brushless motor 1 configured as described above includes a stator 20 and a rotor 10 rotatably provided inside the stator 20 . The rotor 10 includes a cylindrical magnet 12 , a magnet case 13 that covers at least a part of the outer peripheral surface of the magnet 12 , a shaft portion (for example, a first cylindrical portion 71 ), and an outer peripheral surface of the magnet case 13 . a rotating shaft 11 having a cylindrical portion (for example, a first cylindrical portion 72) that partially covers the rotating shaft 11; The magnet case 13 is press-fitted into the magnet 12 and has a concave portion (for example, a first concave portion 911 ) at the end portion of the magnet 12 in the center line direction, which is recessed toward the center line side from the center portion. (for example, the first cylindrical portion 72) is press-fitted into the recess (for example, the first recess 911) of the magnet case 13. As shown in FIG. In this way, the magnet case 13 is press-fitted into the magnet 12, and the rotating shaft 11 is press-fitted into the recess (for example, the first recess 911) of the magnet case 13, so that the dimensional variation between parts and assembly errors are small. As a result, the center line (rotation axis) of the rotating shaft 11 and the center line (rotation axis) of the magnet 12 are likely to coincide with each other. As a result, according to the brushless motor 1, the deflection and unbalance amount of the rotor 10 are reduced, so vibration can be suppressed. In addition, for example, compared to a configuration in which the cylindrical portion (for example, the first cylindrical portion 72) of the rotating shaft 11 is fitted in a magnet case that does not have a recessed portion at the end in the axial direction, the outer circumference of the magnet 12 is reduced. The air gap between surface 121 and coils 21 of stator 20 can be reduced. As a result, since the magnetic flux density of the air gap can be increased, the rotation performance of the brushless motor 1 can be improved. Further, according to the brushless motor 1, the magnet case 13 covers at least a part of the outer peripheral surface of the magnet 12. Therefore, even if the rotor 10 is rotated at a high speed, the magnet 12 can be prevented from being damaged and the magnet 12 can be prevented from being damaged. It is possible to suppress the occurrence of rust even without surface treatment such as nickel plating. In addition, since the cylindrical portion (for example, the first cylindrical portion 72) of the rotating shaft 11 covers the outer peripheral surface (for example, the first outer peripheral surface 913) of the axial end portion of the magnet case 13, the rotor 10 can operate at a high speed. Even if the magnet case 13 is rotated, it is possible to suppress the occurrence of vibration due to deformation of the axial end portion (for example, the first end portion 91) of the magnet case 13. In addition, since the axial end face of the magnet 12 (for example, the first end face 122) and the axial end face (for example, the first end face 731) of the rotating shaft 11 facing this end face are not joined, these end faces are Inclination of the center line of the magnet 12 with respect to the center line of the rotating shaft 11 can be suppressed compared to the case where they are joined together.

In the brushless motor 1 according to the first embodiment, the outer peripheral surface (for example, the first outer peripheral surface 913) of the recess (for example, the first recess 911) of the magnet case 13 and the cylindrical portion (for example, the first recess) of the rotating shaft 11 1 cylindrical portion 72) (for example, the first inner peripheral surface 721) is adhered. Since the magnet case 13 and the rotating shaft 11 are adhered to each other in this way, the magnet case 13 and the rotating shaft 11 can be easily rotated together. Further, by bonding the magnet case 13 and the rotating shaft 11 with an adhesive, the magnet case 13 and the rotating shaft 11 can be easily integrated.
Note that the method of joining the magnet case 13 and the rotating shaft 11 is not limited to adhesion. For example, the magnet case 13 and the rotating shaft 11 may be adhered together. Alternatively, the magnet case 13 and the rotating shaft 11 may be welded together.

Further, in the brushless motor 1 according to the first embodiment, the magnet case 13 is cylindrical and has a concave portion (for example, the first concave portion 911) at the end portion in the center line direction. Thereby, the rotating shaft 11 and the magnet case 13 can be easily press-fitted.
The outer diameter of the central outer peripheral surface 931 of the central portion 93 of the magnet case 13 and the diameter of the outer peripheral surfaces of the first cylindrical portion 72 and the second cylindrical portion 82 of the rotating shaft 11 are preferably the same. As a result, for example, compared with the case where the diameter of the outer peripheral surface of the first cylindrical portion 72 and the second cylindrical portion 82 of the rotating shaft 11 is larger than the diameter of the central outer peripheral surface 931 of the central portion 93 of the magnet case 13. As a result, the air gap between the magnets 12 and the coils 21 of the stator 20 can be reduced. As a result, since the magnetic flux density of the air gap can be increased, the rotation performance of the brushless motor 1 can be improved.

The first cylindrical portion 71 of the first rotating shaft 70 and the second cylindrical portion 81 of the second rotating shaft 80 of the rotating shaft 11, which are rotatably supported by the first bearing 34 and the second bearing 35, are , but not limited to the cylindrical portion. For example, the first columnar portion 71 and the second columnar portion 81 may be cylindrical.

FIG. 3 is a diagram showing an example of a method for manufacturing the rotor 10 according to the first embodiment.
First, as shown in FIG. 3(a), an adhesive is applied to the outer peripheral surface 121 of the cylindrical magnet 12, and the magnet 12 and the material of the cylindrical magnet case 13 are tightly fitted together. (press fit).
Next, as shown in FIG. 3B, the material of the cylindrical magnet case 13 is cut using a lathe to form the first concave portion 911 and the second concave portion 921 . Further, using a lathe, the first end surface 122 and the second end surface 123 of the magnet 12 are cut, and the one end surface and the other end surface of the magnet case 13 are cut into the first end surface 122 and the other end surface of the magnet 12, respectively. At the same time as cutting the second end surface 123, the cutting is performed. As a result, both axial end surfaces of the magnet 12 and the magnet case 13 are flattened with high accuracy.

Next, as shown in FIG. 3C, an adhesive is applied onto the first outer peripheral surface 913 of the first concave portion 911 of the magnet case 13, and the first cylindrical portion of the first rotating shaft 70 is attached to the first concave portion 911. The shaped portion 72 is fitted (press-fitted) with an interference fit. As a result, the magnet case 13 and the first rotating shaft 70 are bonded with an adhesive. Also, an adhesive is applied onto the second outer peripheral surface 923 of the second concave portion 921 of the magnet case 13, and the second cylindrical portion 82 of the second rotating shaft 80 is fitted into the second concave portion 921 by interference fit ( press fit). As a result, the magnet case 13 and the second rotating shaft 80 are bonded with an adhesive.

As described above, the method of manufacturing the rotor 10 includes the step of press-fitting the magnet case 13 that covers at least a portion of the outer peripheral surface of the magnet 12 into the cylindrical magnet 12; and forming a concave portion (for example, the first concave portion 911) recessed from the outer peripheral surface of the central portion 93 (for example, the central outer peripheral surface 931). In addition, the manufacturing method of the rotor 10 includes the magnet case 13, and the rotating shaft 11 having a shaft portion (for example, the first cylindrical portion 71) and a cylindrical portion (for example, the first cylindrical portion 72). , relatively moving in the direction of the center line to press-fit the concave portion of the magnet case 13 (for example, the first concave portion 911) and the cylindrical portion of the rotating shaft 11 (for example, the first cylindrical portion 72).

In this way, the magnet case 13 is press-fitted into the magnet 12, and the rotary shaft 11 is press-fitted into the recessed portion (eg, the first recessed portion 911) of the magnet case 13, thereby reducing dimensional variations and assembly errors between parts. The center line (rotation axis) of the rotating shaft 11 and the center line (rotation axis) of the magnet 12 can be easily aligned. As a result, according to the brushless motor 1, the deflection and unbalance amount of the rotor 10 are reduced, so vibration can be suppressed.

A central recessed portion 733 recessed from the first end surface 731 of the first connection portion 73 is formed in the center portion of the first end surface 731 of the first connecting portion 73 in the first rotating shaft 70 . The central concave portion 733 is a convex portion protruding in the axial direction from the central portion of the first end surface 122, which may be caused by cutting the first end surface 122 of the magnet 12 using a lathe. It is shaped to prevent contact with the end surface 731 . Similarly, in the second rotary shaft 80 , a central recessed portion 833 recessed from the second end surface 831 of the second connecting portion 83 is formed in the center portion of the second end surface 831 .

<Second embodiment>
FIG. 4 is a diagram showing an example of a cross section of the brushless motor 2 according to the second embodiment.
A brushless motor 2 according to the second embodiment differs from the brushless motor 1 according to the first embodiment in a rotor 210 corresponding to the rotor 10 . Differences from the first embodiment will be described below. Elements having the same shape and function in the first embodiment and the second embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

A rotor 210 according to the second embodiment has a rotating shaft 11, a magnet 12, and a magnet case 213 that covers a part of an outer peripheral surface 121 of the magnet 12, a first end surface 122, and a second end surface 123. there is

The magnet case 213 has a first case 230 press-fitted into one end of the magnet 12 and a second case 240 press-fitted into the other end of the magnet 12 . The first rotating shaft 70 is press-fitted into the first case 230 and the second rotating shaft 80 is press-fitted into the second case 240 .

The first case 230 has a cylindrical first cylindrical portion 231 and a first cover portion 232 that covers the opening on one side of the first cylindrical portion 231 . A first recess 234 recessed from an outer peripheral surface 233 on the other side is formed at one end in the axial direction of the first case 230 .
The first case 230 is formed by cutting one surface of the first concave portion 234 and the first cover portion 232 using a lathe from a bottomed cylindrical material.

The second case 240 has a cylindrical second cylindrical portion 241 and a second cover portion 242 that covers the opening on the other side of the second cylindrical portion 241 . The second case 240 has a second recess 244 recessed from the outer peripheral surface 243 on one side at the other end in the axial direction.
The second case 240 is formed by cutting the other surface of the second concave portion 244 and the second cover portion 242 using a lathe from a bottomed cylindrical material.

The first outer peripheral surface 235 of the first recessed portion 234 is a surface parallel to the axial direction, and the diameter of the first outer peripheral surface 235 is larger than the diameter of the outer peripheral surface of the first cylindrical portion 231 on the other side of the first recessed portion 234 . is also small. In addition, the second outer peripheral surface 245 of the second recess 244 is a surface parallel to the axial direction, and the diameter of the second outer peripheral surface 245 is the diameter of the outer peripheral surface on one side of the second cylindrical portion 241 relative to the second recess 244 . smaller than diameter. It can be exemplified that the diameter of the first outer peripheral surface 235 of the first recess 234 and the diameter of the second outer peripheral surface 245 of the second recess 244 are the same.

The diameter of the outer peripheral surface of the first columnar portion 71 of the first rotating shaft 70 is smaller than the diameter of the first outer peripheral surface 235 of the first concave portion 234 of the first case 230 . In addition, the diameter of the first inner peripheral surface 721 of the first cylindrical portion 72 of the first rotating shaft 70 is the first diameter of the first case 230 before the first cylindrical portion 72 is press-fitted into the first case 230 . It is slightly smaller than the diameter of the first outer peripheral surface 235 of the recess 234 . The first cylindrical portion 72 is fitted to the first case 230 by interference fit. However, the first cylindrical portion 72 may be fitted to the first case 230 with an intermediate fit. In the first rotating shaft 70, the first cylindrical portion 72 covers part of the first outer peripheral surface 235 of the first concave portion 234 of the first case 230, and the first end surface 731 of the first connecting portion 73 is , is attached to the first case 230 so as to contact one end face of the first cover portion 232 of the first case 230 . A first end surface 731 of the first connection portion 73 of the first rotating shaft 70 is not joined to one end surface of the first cover portion 232 of the first case 230 by adhesion, adhesion, welding, or the like.

When the first rotating shaft 70 and the first case 230 are assembled, the first rotating shaft is axially aligned with the adhesive applied on the first outer peripheral surface 235 of the first concave portion 234 of the first case 230. 70 and first case 230 are moved relative to each other. For example, the first rotating shaft 70 is moved from one side in the axial direction to the other side with respect to the first case 230 . The adhesive intervenes between the first inner peripheral surface 721 of the first cylindrical portion 72 of the first rotary shaft 70 and the first outer peripheral surface 235 of the first concave portion 234 of the first case 230, The rotating shaft 70 and the first case 230 are adhered. Also, part of the adhesive moves from one side to the other side in the axial direction as the first rotating shaft 70 and the first case 230 are moved relative to each other, and the first cylindrical portion 72 and the other end of the first recess 234 of the first case 230 . The adhesive that has moved into this gap is removed, for example, by wiping it off, if necessary.

The diameter of the outer peripheral surface of the second cylindrical portion 81 of the second rotating shaft 80 is smaller than the diameter of the second outer peripheral surface 245 of the second concave portion 244 of the second case 240 . Moreover, the diameter of the second inner peripheral surface 821 of the second cylindrical portion 82 of the second rotating shaft 80 is the second diameter of the second case 240 before the second cylindrical portion 82 is press-fitted into the second case 240 . It is slightly smaller than the diameter of the second outer peripheral surface 245 of the recess 244 . The second cylindrical portion 82 is fitted to the second case 240 by interference fit. However, the second cylindrical portion 82 may be fitted to the second case 240 with an intermediate fit. In the second rotating shaft 80, the second cylindrical portion 82 partially covers the second outer peripheral surface 245 of the second concave portion 244 of the second case 240, and the second end surface 831 of the second connecting portion 83 is , is attached to the second case 240 so as to contact the other end face of the second cover portion 242 of the second case 240 . The second end surface 831 of the second connecting portion 83 of the second rotating shaft 80 is not joined to the other end surface of the second cover portion 242 of the second case 240 by adhesion, adhesion, welding, or the like.

When the second rotating shaft 80 and the second case 240 are assembled, the second rotating shaft 80 is axially aligned with the adhesive applied on the second outer peripheral surface 245 of the second concave portion 244 of the second case 240. 80 and second case 240 are moved relative to each other. For example, the second rotating shaft 80 is moved from the other side in the axial direction to the one side with respect to the second case 240 . The adhesive intervenes between the second inner peripheral surface 821 of the second cylindrical portion 82 of the second rotating shaft 80 and the second outer peripheral surface 245 of the second concave portion 244 of the second case 240, The rotating shaft 80 and the second case 240 are adhered. In addition, part of the adhesive moves from the other side to the one side in the axial direction as the second rotating shaft 80 and the second case 240 are moved relative to each other, and the second cylindrical portion 82 and one end of the second recess 244 of the second case 240 . The adhesive that has moved into this gap is removed, for example, by wiping it off, if necessary.

The brushless motor 2 configured as described above includes a stator 20 and a rotor 210 rotatably provided inside the stator 20 . The rotor 210 includes a cylindrical magnet 12 , a magnet case 213 covering at least a part of the outer peripheral surface of the magnet 12 , a shaft portion (for example, the first cylindrical portion 71 ), and the outer peripheral surface of the magnet case 213 . a rotating shaft 11 having a cylindrical portion (for example, a first cylindrical portion 72) that partially covers the rotating shaft 11; The magnet case 213 is press-fitted into the magnet 12 and has a concave portion (for example, a first concave portion 234 ) at the end portion of the magnet 12 in the center line direction, which is recessed toward the center line side from the center portion. (for example, the first cylindrical portion 72 ) is press-fitted into the recess (for example, the first recess 234 ) of the magnet case 213 . In this way, the magnet case 213 is press-fitted into the magnet 12, and the rotating shaft 11 is press-fitted into the recess (for example, the first recess 234) of the magnet case 213. Therefore, the dimensional variation between parts and assembly errors are small. As a result, the center line (rotation axis) of the rotating shaft 11 and the center line (rotation axis) of the magnet 12 are likely to coincide with each other. As a result, according to the brushless motor 2, since the deflection and unbalance amount of the rotor 10 are reduced, vibration can be suppressed. In addition, for example, compared to a configuration in which the cylindrical portion (for example, the first cylindrical portion 72) of the rotating shaft 11 is fitted in a magnet case that does not have a recessed portion at the end in the axial direction, the outer circumference of the magnet 12 is reduced. The air gap between the surface and the coils 21 of the stator 20 can be reduced. As a result, since the magnetic flux density of the air gap can be increased, the rotation performance of the brushless motor 2 can be improved. Further, according to the brushless motor 2, since the magnet case 213 covers at least a part of the outer peripheral surface of the magnet 12, even if the rotor 210 is rotated at a high speed, damage to the magnet 12 can be suppressed and the magnet 12 can be prevented from being damaged. It is possible to suppress the occurrence of rust even without surface treatment such as nickel plating. In addition, since the magnet case 213 covers the end face (for example, the first end face 122) of the magnet 12 in the axial direction, the rigidity and mechanical strength of the connecting portion between the rotating shaft 11 (for example, the first rotating shaft 70) and the magnet 12 are improved. can increase In addition, since the cylindrical portion (for example, the first cylindrical portion 72) of the rotating shaft 11 covers the outer peripheral surface (for example, the first outer peripheral surface 235) of the end portion in the axial direction of the magnet case 213, the rotor 210 rotates at a high speed. Even if the magnet case 213 is rotated, it is possible to suppress the occurrence of vibration due to deformation of the magnet case 213 or the like. Further, an axial end face of the magnet case 213 (for example, one end face of the first cover portion 232) and an axial end face of the rotating shaft 11 facing this end face (for example, the first end face 731) are joined. Therefore, the inclination of the center line of the magnet 12 with respect to the center line of the rotating shaft 11 can be suppressed compared to the case where these end faces are joined to each other.

The magnet case 213 includes a cylindrical case cylindrical portion (for example, a first cylindrical portion 231) that partially covers the outer peripheral surface of the magnet 12, and an end face (for example, a first end face 122) in the center line direction of the magnet 12. and a recess (for example, the first It has a recess 234). Thereby, the rotating shaft 11 and the magnet case 213 can be easily press-fitted.

FIG. 5 is a diagram showing an example of a method for manufacturing the rotor 210 according to the second embodiment.
First, as shown in FIG. 5A, an adhesive is applied onto the outer peripheral surface 121 of the cylindrical magnet 12, and the magnet 12, the material of the first case 230 and the material of the second case 240 are bonded together. Fit (press fit) with interference fit.
At this time, if the air accumulated inside the bottomed cylindrical first case 230 and the second case 240 prevents the magnet 12 from being press-fitted inside the first case 230 and the second case 240, Even if the first cover portion 232 of the first case 230 and the second cover portion 242 of the second case 240 are formed with through holes for removing air from the insides of the first case 230 and the second case 240, good. This through hole can be exemplified as a circular through hole centered on the center line of the magnet 12 .

Next, as shown in FIG. 5B, the first recess 234 is formed by cutting the material of the first case 230 using a lathe. Further, one surface of the first cover portion 232 of the first case 230 is formed by cutting using a lathe. Further, the material of the second case 240 is cut using a lathe to form the second concave portion 244 . Further, the other side surface of the second cover portion 242 of the second case 240 is formed by cutting using a lathe.

Next, as shown in FIG. 5(c), an adhesive is applied onto the first outer peripheral surface 235 of the first recess 234 of the first case 230, and the first rotation shaft 70 is attached to the first recess 234. The cylindrical portion 72 is fitted (press-fitted) with an interference fit. As a result, the first case 230 and the first rotating shaft 70 are bonded with an adhesive. Also, an adhesive is applied onto the second outer peripheral surface 245 of the second recess 244 of the second case 240, and the second cylindrical portion 82 of the second rotating shaft 80 is fitted into the second recess 244 by interference fit. (press fit). Thereby, the second case 240 and the second rotating shaft 80 are bonded with an adhesive.

As described above, the method of manufacturing the rotor 210 includes a step of press-fitting the magnet case 213 that covers at least a portion of the outer peripheral surface of the magnet 12 into the cylindrical magnet 12, and forming a recess (for example, the first recess 234) recessed from the outer peripheral surface of the central portion (for example, the outer peripheral surface 233 on the other side) by cutting. In addition, the manufacturing method of the rotor 210 includes the magnet case 213, and the rotating shaft 11 having a shaft portion (for example, the first cylindrical portion 71) and a cylindrical portion (for example, the first cylindrical portion 72). , relatively moving in the centerline direction to press fit the recess (eg, the first recess 234) and the cylindrical portion (eg, the first cylindrical portion 72).

In this manner, the magnet case 213 is press-fitted into the magnet 12, and the rotating shaft 11 is press-fitted into the recessed portion (eg, the first recessed portion 234) of the magnet case 213, thereby reducing dimensional variations between parts and assembly errors. The center line (rotation axis) of the rotating shaft 11 and the center line (rotation axis) of the magnet 12 can be easily aligned. As a result, according to the brushless motor 2, since the deflection and unbalance amount of the rotor 10 are reduced, vibration can be suppressed.

In addition, in the present invention, the shape of the rotor is not limited to the shapes of the rotor 10 and the rotor 210, and may be other shapes.

Reference Signs List 1, 2 Brushless motor 10, 210 Rotor 11 Rotating shaft 12 Magnet 13, 213 Magnet case 20 Stator 21 Coil 30 Housing 50 Detector 71 First cylindrical portion 72, 231 First cylindrical portion 81 Second cylindrical portion 82, 241 Second cylindrical portion 230 First case 232 First cover portion 234,911 1st concave portion 235, 913 1st outer peripheral surface 240 2nd case 242 2nd covering portion 244, 921 2nd concave portion 245, 923 2nd outer peripheral surface

Claims (4)

A rotor rotatable about a predetermined centerline,
a columnar magnet,
a magnet case that covers at least a portion of the outer peripheral surface of the magnet;
a rotating shaft having a shaft portion and a cylindrical portion;
with
The cylindrical portion of the rotating shaft covers the outer peripheral surface of the end portion of the magnet case in the centerline direction ,
The magnet case has a case tubular portion that covers an outer peripheral surface of the end portion of the magnet in the centerline direction, and a cover portion that covers the end surface of the end portion of the magnet in the centerline direction,
The outer peripheral surface of the case tubular portion of the magnet case and the inner peripheral surface of the tubular portion of the rotating shaft are joined, and the end surface of the cover portion of the magnet case in the center line direction. , the end face in the center line direction of the rotating shaft facing the end face is not joined
rotor. The rotor according to claim 1 , wherein the cover portion has a through hole. a stator;
A brushless motor comprising: the rotor according to claim 1 or 2 rotatably provided inside the stator. A method for manufacturing a rotor rotatable about a predetermined centerline, comprising:
a step of press-fitting a magnet case covering at least a portion of the outer peripheral surface of the magnet into the columnar magnet;
a step of cutting the outer peripheral surface of the end portion of the magnet case in the center line direction to form a recess recessed from the outer peripheral surface of the central portion toward the center line;
a step of simultaneously cutting an end surface of the magnet and an end surface of the magnet case on the same side of the one side and the other side in the center line direction while the magnet case is press-fitted into the magnet;
The magnet case and a rotating shaft having a shaft portion and a cylindrical portion are relatively moved in the center line direction, and the concave portion of the magnet case and the cylindrical portion of the rotating shaft are press-fitted. process and
A method for manufacturing a rotor having

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