JP2015029381A - Rotor and motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotor and a motor which can prevent damage on a field magnet, by preventing the field magnet from being loaded during assembly work.SOLUTION: A rotor 4 fixes a field magnet 40 for a fixed cylinder 15 pressure fixed to a rotating shaft 3. A first rotor core 20 and a second rotor core 30 are press fitted for the rotating shaft 3 toward the fixed cylinder 15, and pressure fixed.

Description

  The present invention relates to a rotor and a motor.

  Conventionally, a rotor core used in a motor has a rotor core that is combined with a plurality of claw-shaped magnetic poles in the circumferential direction, and field magnets are arranged between them to make the claw-shaped magnetic poles alternately different magnetic poles. A so-called permanent magnet field Landell-type rotor is known (for example, see Patent Document 1).

  In addition, in the Landel-type rotor, in order to increase the output of the motor, an interpole magnet for rectifying a magnetic path between alternately arranged claw-shaped magnetic poles has been proposed. (For example, refer to Patent Document 2).

Japanese Utility Model Publication No. 5-43749 JP 2012-115085 A

  By the way, the rotor of the Landel structure is assembled by arranging a field magnet between a pair of rotor cores. In the assembling work, when the rotor core is press-fitted and fixed to the rotating shaft, a load is directly applied to the field magnets arranged between the rotor cores. Therefore, the field magnet may be damaged such as a crack due to the load.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to prevent a load applied to a field magnet during an assembly operation and to prevent the field magnet from being damaged. Is to provide.

  A rotor for solving the above problems includes a first rotor core having a plurality of first claw-shaped magnetic poles formed at equal intervals in the circumferential direction, and a first rotor core having a plurality of second claw-shaped magnetic poles formed at equal intervals in the circumferential direction. Two rotor cores and a field magnet disposed between the first and second rotor cores, such that the first claw-shaped magnetic poles and the second claw-shaped magnetic poles are alternately disposed in the circumferential direction. A rotor in which the first and second rotor cores are fixed to a rotation shaft, and the first claw-shaped magnetic pole functions as a first magnetic pole and the second claw-shaped magnetic pole functions as a second magnetic pole by the field magnet. The large-diameter portion is formed on the rotating shaft, the field magnet is inserted through the large-diameter portion, and the first rotor core is brought into contact with the one-side step surface in the axial direction of the large-diameter portion. Press-fit to the rotary shaft to a position, and the second rotor core Rotor and wherein the press-fitted to said rotary shaft to a position abutting the other side stepped surface direction.

  According to the above rotor, when the first rotor core is press-fitted into the rotating shaft, the first rotor core is brought into contact with the one-side step surface of the large-diameter portion, and further press-fitting in the axial direction (field magnet side) is restricted. Therefore, since the load from the first rotor core is not directly applied to the field magnet when the first rotor core is press-fitted into the rotating shaft, there is no risk of damage such as cracking.

  Further, when the second rotor core is press-fitted into the rotating shaft, the second rotor core abuts against the other step surface of the large-diameter portion, and further press-fitting in the axial direction (field magnet side) is restricted. Therefore, when the second rotor core is press-fitted into the rotation shaft, the load from the second rotor core is not directly applied to the field magnet, so there is no risk of damage such as cracking.

In the rotor, it is preferable that an axial length of the large diameter portion is the same as an axial length of the field magnet.
According to the rotor, the axial length of the large diameter portion is the same as the axial length of the field magnet. Therefore, the first and second rotor cores can be easily brought into close contact with the field magnet without applying a load when the first and second rotor cores are press-fitted and pressed.

In the rotor, it is preferable that the rotating shaft is formed of a nonmagnetic material, and the large diameter portion is formed integrally with the rotating shaft.
According to the rotor, the magnetic flux of the field magnet can be prevented from flowing through the large diameter portion together with the rotating shaft made of a non-magnetic material as a leakage magnetic flux.

  In the rotor, the rotating shaft is formed of a non-magnetic material, and the large-diameter portion is integrally formed or press-fitted into the rotating shaft with a cylindrical body made of a non-magnetic material separate from the rotating shaft. It is preferable to be formed.

  According to the rotor, the field magnet is inserted into the cylindrical body that is integrally formed or press-fitted and fixed to the rotating shaft. And the 1st rotor core contacts the axial direction one side end surface of a cylinder, and the press injection in the axial direction (field magnet side) is controlled further. Further, the second rotor core is in contact with the other end face in the axial direction of the cylindrical body, and the press-fitting in the axial direction (field magnet side) is further restricted.

A motor for solving the above problems includes the rotor.
According to the motor described above, the field magnet is not directly subjected to loads from the first and second rotor cores during assembly work, so there is no risk of damage such as cracking.

  According to the present invention, the field magnet can be prevented from being damaged.

Sectional drawing seen from the axial direction of the brushless motor. Similarly, (a) is a perspective view of the rotor viewed from the first rotor core side, and (b) is a perspective view of the rotor viewed from the second rotor core side. Similarly, the front view which looked at the rotor from the axial direction. Similarly, the AOB line combination sectional drawing of FIG. Similarly, the exploded perspective view of a rotor. Sectional drawing of the rotor which shows another example of this invention.

Hereinafter, an embodiment of the motor will be described.
As shown in FIG. 1, a brushless motor M has a stator 2 fixed to an inner peripheral surface of a motor housing 1, and a so-called Landel that is fixed to a rotating shaft 3 and rotates integrally with the rotating shaft 3 inside the stator 2. A rotor 4 having a mold structure is provided. The rotating shaft 3 is a non-magnetic stainless steel shaft and is supported by a bearing (not shown) provided on the motor housing 1 so as to be rotatable with respect to the motor housing 1.

(Stator 2)
The stator 2 has a cylindrical stator core 10, and the outer peripheral surface of the stator core 10 is fixed to the inner surface of the motor housing 1. Inside the stator core 10, a plurality of teeth 11 formed along the axial direction and arranged at equal pitches in the circumferential direction are formed extending inward in the radial direction. Each tooth 11 is a T-shaped tooth, and an inner circumferential surface 11 a in the radial direction is an arc surface obtained by extending a concentric arc centering on the central axis O of the rotating shaft 3 in the axial direction.

  A slot 12 is formed between the teeth 11. In the present embodiment, the number of teeth 11 is twelve, and the number of slots 12 is twelve, which is the same as the number of teeth 11. Around the 12 teeth 11, a three-phase winding, that is, a U-phase winding 13u, a V-phase winding 13v, and a W-phase wire 13w are wound in order in a concentrated manner in the circumferential direction.

  Then, a three-phase power supply voltage is applied to each of the wound phase windings 13u, 13v, and 13w to form a rotating magnetic field in the stator 2, and the rotor 4 fixed to the rotating shaft 3 disposed inside the stator 2 is provided. Are rotated in the forward direction (clockwise direction in FIG. 1) and in the reverse direction (rotated in the counterclockwise direction in FIG. 1).

(Rotor 4)
As shown in FIGS. 2 to 5, the rotor 4 is disposed inside the stator 2. The rotor 4 includes a fixed cylinder 15, first and second rotor cores 20 and 30, and a field magnet 40.

(Fixed cylinder 15)
As shown in FIGS. 4 and 5, the fixed cylinder 15 is made of a non-magnetic material and is made of the same stainless steel as the cylindrical rotary shaft 3 in this embodiment. An inner peripheral surface of the fixed cylinder 15 is press-fitted to the outer peripheral surface of the rotary shaft 3 and is fixed to the rotary shaft 3.

A field magnet 40 is disposed on the outer peripheral surface of the fixed cylinder 15. That is, the fixed cylinder 15 is inserted into the through hole 41 of the field magnet 40.
The axial length of the fixed cylinder 15 (the length from the first end surface 15a to the second end surface 15b) is the axial length of the field magnet 40 in this embodiment (the length from the side surface 40a to the side surface 40b). ).

(First rotor core 20)
As shown in FIG. 5, the first rotor core 20 has a disc-shaped first core base 21 formed of an electromagnetic steel plate made of a soft magnetic material. A through hole 20 a into which the rotation shaft 3 is inserted is formed at the center of the first core base 21. The first core base 21 is pressure-bonded and fixed at a predetermined position of the rotary shaft 3 by press-fitting the through hole 20a into the rotary shaft 3.

  On the outer peripheral surface 21c of the first core base 21, a plurality of (four in the present embodiment) first claw-shaped magnetic poles 22 project radially outward and extend in the axial direction at equal intervals. Here, in the first claw-shaped magnetic pole 22, a portion protruding radially outward from the outer peripheral surface 21 c of the first core base 21 is referred to as a first base portion 23, and a tip portion bent in the axial direction is the first magnetic pole portion 24. That's it.

  Both circumferential end surfaces 22a and 22b of the first claw-shaped magnetic pole 22 composed of the first base portion 23 and the first magnetic pole portion 24 are flat surfaces extending in the radial direction. And the angle of the circumferential direction centering on the central axis O of the rotating shaft 3 of each 1st nail | claw-shaped magnetic pole 22, ie, the angle between the said circumferential direction both end surfaces 22a and 22b, is a 1st nail | claw-shaped magnetic pole adjacent to the circumferential direction. It is set smaller than the angle of the gap between 22.

Further, the radially outer peripheral surface f1a of the first magnetic pole portion 24 has a concentric circular arc surface in which the axial orthogonal cross-sectional shape is centered on the central axis O of the rotating shaft 3.
(Second rotor core 30)
As shown in FIG. 5, the second rotor core 30 has a disk-shaped second core base 31 that is made of the same material and shape as the first rotor core 20 and is made of an electromagnetic steel plate. A through hole 30 a through which the rotation shaft 3 is inserted is formed at the center of the second core base 31. The second core base 31 is pressure-bonded and fixed at a predetermined position of the rotary shaft 3 by press-fitting the through hole 30 a into the rotary shaft 3.

  On the outer peripheral surface 31c of the second core base 31, four second claw-shaped magnetic poles 32 are formed at equal intervals so as to protrude radially outward and extend in the axial direction. Here, in the second claw-shaped magnetic pole 32, a portion that protrudes radially outward from the outer peripheral surface 31 c of the second core base 31 is referred to as a second base portion 33, and a tip portion bent in the axial direction is the second magnetic pole portion 34. That's it.

  The circumferential end surfaces 32a and 32b of the second claw-shaped magnetic pole 32 composed of the second base portion 33 and the second magnetic pole portion 34 are flat surfaces extending in the radial direction. And the angle of the circumferential direction centering on the central axis O of the rotating shaft 3 of each 2 claw-shaped magnetic pole 32, ie, the angle between the said circumferential direction both end surfaces 32a and 32b, is the 2nd claw-shaped magnetic pole adjacent to the circumferential direction. It is set smaller than the angle of the gap between 32.

The radial outer circumferential surface f <b> 2 a of the second magnetic pole portion 34 has a concentric circular arc surface with the axial orthogonal cross-sectional shape centering on the central axis O of the rotating shaft 3.
The second rotor core 30 is disposed between the first claw-shaped magnetic poles 22 to which the second claw-shaped magnetic poles 32 respectively correspond. At this time, the second rotor core 30 is positioned relative to the first rotor core 20 such that the field magnet 40 (see FIG. 4) is disposed between the first core base 21 and the second core base 31 in the axial direction. Assembled.

(Field magnet 40)
As shown in FIGS. 4 and 5, the field magnet 40 is a disk-like permanent magnet made of a neodymium magnet, and a through hole 41 is formed at the center thereof. The field magnet 40 is inserted through the fixed cylinder 15 in the through hole 41. Then, one side surface 40a of the field magnet 40 is in close contact with the facing surface 21a of the first core base 21, and the other side surface 40b of the field magnet 40 is in close contact with the facing surface 31a of the second core base 31, respectively. Adhesive and fixed with a magnetic adhesive.

The outer diameter of the field magnet 40 is set to coincide with the outer diameters of the first and second core bases 21 and 31, and the thickness (axial length) coincides with the axial length of the fixed cylinder 15. I am letting.
That is, as shown in FIG. 4, when the field magnet 40 is disposed between the first rotor core 20 and the second rotor core 30, the tip surface 22c of the first claw-shaped magnetic pole 22 (first magnetic pole portion 24) and The opposite surface 31b of the second core base 31 is flush with the surface. Similarly, the tip surface 32c of the second claw-shaped magnetic pole 32 (second magnetic pole portion 34) and the opposite surface 21b of the first core base 21 are flush with each other. Further, the outer peripheral surface 40 c of the field magnet 40 is flush with the outer peripheral surfaces 21 c and 31 c of the first and second core bases 21 and 31.

  As shown in FIG. 4, the field magnet 40 is magnetized in the axial direction. The first rotor core 20 side is an N pole (first magnetic pole), and the second rotor core 30 side is an S pole (second magnetic pole). It is magnetized so that Therefore, by this field magnet 40, the first claw-shaped magnetic pole 22 of the first rotor core 20 functions as an N pole (first magnetic pole), and the second claw-shaped magnetic pole 32 of the second rotor core 30 functions as an S pole (second magnetic pole). Function as a magnetic pole).

  Therefore, the rotor 4 of the present embodiment is a so-called Landell type rotor using the field magnet 40. In the rotor 4, first claw-shaped magnetic poles 22 that are N poles and second claw-shaped magnetic poles 32 that are S poles are alternately arranged in the circumferential direction, and the number of magnetic poles is eight.

(First and second back auxiliary magnets 51 and 52)
As shown in FIG. 4, it is the back surface f1b (radially inner surface) of the first magnetic pole portion 24, and the outer peripheral surface 31c of the second core base 31, the outer peripheral surface 40c of the field magnet 40, and the first base portion 23. A first back auxiliary magnet 51 is arranged and fixed in a space formed by the surface 23a on the second rotor core 30 side.

  The first back auxiliary magnet 51 has a substantially rectangular parallelepiped shape in which the cross section in the direction perpendicular to the axis has a fan shape, and the side that contacts the back surface f1b of the first magnetic pole portion 24 is the first claw so as to reduce the leakage magnetic flux at that portion. The magnetic pole 22 is magnetized in the radial direction so that the N pole having the same polarity as the magnetic pole 22 is the S pole having the same polarity as the second core base 31 on the side in contact with the second core base 31.

  On the other hand, as shown in FIG. 4, it is the back surface f2b (radially inner surface) of the second magnetic pole portion 34, and the outer peripheral surface 21c of the first core base 21, the outer peripheral surface 40c of the field magnet 40, and the second base portion. A second back auxiliary magnet 52 is disposed and fixed in a space formed by the surface 33 a on the first rotor core 20 side of 33.

  The second back auxiliary magnet 52 has a substantially rectangular parallelepiped shape in which the cross section in the direction perpendicular to the axis is fan-shaped, and the side that contacts the back surface f2b of the second magnetic pole portion 34 is the second claw so as to reduce the leakage magnetic flux at that portion. The S pole having the same polarity as the magnetic pole 32 is magnetized in the radial direction so that the side in contact with the first core base 21 becomes the N pole having the same polarity as the first core base 21.

(Auxiliary magnets 53 and 54 between the first and second poles)
Between the first claw-shaped magnetic pole 22 in which the first back auxiliary magnet 51 is arranged and the second claw-shaped magnetic pole 32 in which the second back auxiliary magnet 52 is arranged, there is a first and second interpole auxiliary. Magnets 53 and 54 are arranged and fixed, respectively. The first and second interpole auxiliary magnets 53 and 54 are formed in a substantially rectangular parallelepiped shape in which the cross section in the direction perpendicular to the axis is a fan shape.

  Specifically, the first inter-pole auxiliary magnet 53 includes a flat surface formed by one circumferential end surface 22a of the first claw-shaped magnetic pole 22 and a circumferential end surface of the first back auxiliary magnet 51, and a second claw. It is disposed between the other circumferential end surface 32 b of the magnetic pole 32 and a flat surface formed by the circumferential end surface of the second back auxiliary magnet 52. The radially outer circumferential surface 53a of the first interpole auxiliary magnet 53 has a concentric circular arc surface whose center is perpendicular to the central axis O of the rotating shaft 3, and the first magnetic pole portion 24 and the second magnetic pole portion 24. The magnetic pole part 34 is formed to be flush with the radially outer peripheral surfaces f1a and f2a.

  Similarly, the second interpole auxiliary magnet 54 includes a flat surface formed by the other circumferential end surface 22b of the first claw-shaped magnetic pole 22 and the circumferential end surface of the first back auxiliary magnet 51, and a second claw-shaped magnet. The magnetic pole 32 is disposed between one circumferential end surface 32 a and a flat surface formed by the circumferential end surface of the second back auxiliary magnet 52. The radially outer circumferential surface 54a of the second interpole auxiliary magnet 54 has a concentric circular arc surface in which the axial orthogonal cross-sectional shape is centered on the central axis O of the rotating shaft 3, and the first magnetic pole portion 24 and the second magnetic pole portion 24 The magnetic pole part 34 is formed to be flush with the radially outer peripheral surfaces f1a and f2a.

  The first and second interpole auxiliary magnets 53 and 54 have the same magnetic poles as the first and second claw-shaped magnetic poles 22 and 32 (the first claw-shaped magnetic pole 22 side is the N pole, and the second claw The magnetic pole 32 is magnetized in the circumferential direction so that the side of the magnetic pole 32 becomes the S pole.

Next, the operation of the brushless motor M configured as described above will be described by explaining a method for assembling the rotor 4.
First, the rotary shaft 3 is press-fitted into the fixed cylinder 15, and the fixed cylinder 15 is fixed to the rotary shaft 3 by pressure. For example, a cylindrical jig is used for the annular first end face 15a of the fixed cylinder 15 in a state where one opening (for example, the opening on the second end face 15b side) of the fixed cylinder 15 is in contact with the rotary shaft 3. Press in the axial direction. When the first end surface 15 a of the fixed cylinder 15 is pressed by a cylindrical jig, the rotating shaft 3 of the fixed cylinder 15 is press-fitted from the other opening of the fixed cylinder 15.

  Subsequently, the fixed cylinder 15 fixed to the rotating shaft 3 is inserted into the through hole 41 of the field magnet 40 to fix the outer peripheral surface of the fixed cylinder 15 and the inner peripheral surface of the through hole 41 of the field magnet 40. To do. At this time, the first end surface 15a and the second end surface 15b in the axial direction of the fixed tube 15 are flush with the respective side surfaces 40a and 40b of the field magnet 40 with respect to the fixed tube 15 with respect to the field magnet. 40 is fixed.

Incidentally, the field magnet 40 is arranged with respect to the fixed cylinder 15 by inserting the through hole 41 into the fixed cylinder 15 press-fitted and fixed to the rotating shaft 3.
Next, the through hole 20a of the first rotor core 20 (first core base 21) is formed on the rotary shaft 3 so that the facing surface 21a of the first core base 21 and the side surface 40a of the field magnet 40 face each other. Press-fit with the method of. At this time, the through hole 20a is pressed into the rotary shaft 3 until the facing surface 21a of the first core base 21 contacts the first end surface 15a in the axial direction of the fixed cylinder 15 (side surface 40a of the field magnet 40). .

  Eventually, the first rotor core 20 is in contact with the first end surface 15a of the fixed cylinder 15 in the vicinity of the opening on the opposite surface 21a side of the through hole 20a. The first rotor core 20 is further restricted from being pressed in the axial direction (field magnet 40 side). Therefore, the first rotor core 20 does not apply a load to the field magnet 40 due to press fitting. As a result, the field magnet 40 is not directly subjected to a load from the first rotor core 20 when the first rotor core 20 is press-fitted into the rotary shaft 3, so that damage such as cracking does not occur.

The opposing surface 21a of the first core base 21 and the side surface 40a of the field magnet 40 may be bonded and fixed with a magnetic adhesive.
Next, with the opposed surface 31a of the second core base 31 and the side surface 40b of the field magnet 40 facing each other, the through hole 30a of the second rotor core 30 (second cobase 31) is formed on the rotary shaft 3 as described above. Press-fit by the method. At this time, press-fitting is performed while adjusting the relative alignment in the circumferential direction with the first rotor core 20 fixed earlier.

Then, the rotating shaft 3 is press-fitted into the through hole 20a until the facing surface 31a of the second core base 31 contacts the second end surface 15b (the side surface 40a of the field magnet 40) of the fixed cylinder 15 in the axial direction.
Eventually, the second rotor core 30 is in contact with the second end face 15b of the fixed cylinder 15 in the vicinity of the opening on the opposite surface 31a side of the through hole 30a. The second rotor core 30 is further restricted from being pressed in the axial direction (field magnet 40 side). Therefore, the second rotor core 30 does not apply a load to the field magnet 40 due to press fitting. As a result, in the field magnet 40, when the second rotor core 30 is press-fitted into the rotary shaft 3, the load from the second rotor core 30 is not directly applied, so that damage such as cracking does not occur.

The opposing surface 31a of the second core base 31 and the side surface 40b of the field magnet 40 may be bonded and fixed with a magnetic adhesive.
Thereby, the first and second rotor cores 20 and 30 are press-fitted and fixed to the rotating shaft 3. Further, the fixed cylinder 15 and the field magnet 40 are arranged between the first rotor core 20 and the second rotor core 30 that are press-fitted and fixed, and are fixed to the fixed cylinder 15.

  Next, the first back auxiliary magnet 51 is arranged and fixed on the back surface f1b of the first magnetic pole part 24, and the second back auxiliary magnet 52 is arranged and fixed on the back surface f2b of each second magnetic pole part 34.

  Specifically, it is the back surface f1b of each first magnetic pole portion 24, the outer peripheral surface 31c of the second core base 31, the outer peripheral surface 40c of the field magnet 40, and the surface 23a of the first base 23 on the second rotor core 30 side. The first back auxiliary magnet 51 is disposed in the space formed by and bonded and fixed with a magnetic adhesive.

  Similarly, it is formed by the back surface f2b of the second magnetic pole portion 34, the outer peripheral surface 21c of the first core base 21, the outer peripheral surface 40c of the field magnet 40, and the surface 33a of the second base 33 on the first rotor core 20 side. The second back auxiliary magnet 52 is arranged and fixed in the space to be formed.

Finally, the first and second interpole auxiliary magnets 53 and 54 are fixedly arranged.
Specifically, the first inter-pole auxiliary magnet 53 includes a flat surface formed by one circumferential end surface 22a of the first claw-shaped magnetic pole 22 and a circumferential end surface of the first back auxiliary magnet 51, and a second surface. The claw-shaped magnetic pole 32 is disposed between the other circumferential end surface 32 b and a flat surface formed by the circumferential end surface of the second back auxiliary magnet 52. Then, the first interpole auxiliary magnet 53 is bonded and fixed with a magnetic adhesive.

  Similarly, the second inter-pole auxiliary magnet 54 includes a flat surface formed by the other circumferential end surface 22b of the first claw-shaped magnetic pole 22 and the circumferential end surface of the first back auxiliary magnet 51, and a second claw-shaped. The magnetic pole 32 is disposed between one circumferential end surface 32 a and a flat surface formed by the circumferential end surface of the second back auxiliary magnet 52. Then, the second interpole auxiliary magnet 54 is fixed.

Thereby, the assembly of the rotor 4 is completed.
Next, the effect of this embodiment will be described.
(1) In the present embodiment, the field magnet 40 is fixed to the fixed cylinder 15 that is pressure-bonded and fixed to the rotary shaft 3, and the first rotor core 20 and the second rotor core 30 are press-fitted and fixed to the rotary shaft 3. Since the rotor 4 can be manufactured, the assembly work of the rotor 4 becomes very simple.

In addition, since the first and second rotor cores 20 and 30 have a strong connection structure that is press-fitted and crimped to the rotating shaft 3, vibration and noise of the rotor 4 due to rotation can be prevented.
(2) In the present embodiment, when the first rotor core 20 is press-fitted into the rotating shaft 3, the first rotor core 20 has a through hole 20 a that has a through hole 20 a near the opening on the side of the facing surface 21 a that contacts the first end surface 15 a of the fixed cylinder 15. In contact therewith, press-fitting in the axial direction (field magnet 40 side) is restricted. Accordingly, the field magnet 40 is not directly subjected to a load from the first rotor core 20 when the first rotor core 20 is press-fitted into the rotary shaft 3, so that there is no possibility of damage such as cracks during the assembly operation. .

  (3) In the present embodiment, when the second rotor core 30 is press-fitted into the rotary shaft 3, the second rotor core 30 is configured such that the periphery of the opening on the facing surface 31 a side of the through hole 30 a contacts the second end surface 15 b of the fixed cylinder 15. In contact therewith, press-fitting in the axial direction (field magnet 40 side) is restricted. Accordingly, the field magnet 40 is not directly subjected to a load from the second rotor core 30 when the second rotor core 30 is press-fitted into the rotary shaft 3, so there is no risk of damage such as cracks during the assembly operation. .

  (4) In the present embodiment, the fixed cylinder 15 is formed of the same nonmagnetic material as the rotary shaft 3 and the fixed cylinder 15 and the field magnet 40 are fixed. Therefore, the magnetic flux of the field magnet 40 can be prevented from flowing through the rotating shaft 3 and the fixed cylinder 15 made of a nonmagnetic material as a leakage magnetic flux.

  (5) According to the present embodiment, the axial length of the fixed cylinder 15 is made the same as the axial length of the field magnet 40 disposed between the first rotor core 20 and the second rotor core 30. Accordingly, the opposing surfaces 21a and 31a of the first and second rotor cores 20 and 30 can be easily brought into close contact with the field magnet 40 without applying a load when the first and second rotor cores 20 and 30 are press-fitted and pressed. Can be made. As a result, the magnetic resistance between the first and second rotor cores 20 and 30 and the field magnet 40 can be reduced.

In addition, you may change the said embodiment as follows.
In the above embodiment, the non-magnetic fixed cylinder 15 is made of the same stainless steel as the rotating shaft 3, but may be any non-magnetic substance such as an aluminum fixed cylinder 15 or a resin-made fixed cylinder 15. The fixed cylinder 15 may be used.

  In the above embodiment, the axial length of the fixed cylinder 15 is the same as the thickness (the axial length) of the field magnet 40. This may be performed by making the axial length of the fixed cylinder 15 longer than the thickness of the field magnet 40. In this case, a gap is generated between the field magnet 40, the first and second rotor cores 20 and 30, and the field magnet 40, leading to an increase in magnetic resistance. Therefore, a range in which a decrease in magnetic flux density does not hinder rotation. Therefore, it is necessary to lengthen the axial length of the fixed cylinder 15.

  In the above embodiment, the fixed cylinder 15 is press-fitted and pressure-bonded to the rotary shaft 3 to form the large-diameter portion of the rotary shaft 3. For example, as shown in FIG. 6, for example, a part of the rotating shaft 3 may be formed into a large diameter, and the large diameter part may be used as the large diameter part 3a. At this time, the first rotor core 20 contacts the one side step surface 3b of the large diameter portion 3a, and the second rotor core 30 contacts the other side step portion 3c of the large diameter portion 3a.

Further, a large-diameter portion having the same shape as the fixed cylinder 15 may be integrally formed on the rotary shaft 3 by insert molding or two-color molding.
In the above embodiment, the field magnet 40 is formed of a neodymium magnet, but is not limited thereto, and may be formed of a ferrite sintered magnet, a samarium cobalt magnet, or the like.

In the above embodiment, the rotor 4 is provided with the first and second back auxiliary magnets 51 and 52, but this may be omitted.
In the above embodiment, the rotor 4 is provided with the first and second interpole auxiliary magnets 53 and 54, but this may be omitted. Of course, the first and second back auxiliary magnets 51 and 52 may be omitted together.

  DESCRIPTION OF SYMBOLS 1 ... Motor housing, 2 ... Stator, 3 ... Rotating shaft, 3a ... Large diameter part, 3b ... One side step surface, 3c ... Other side step surface, 4 ... Rotor, 10 ... Stator core, 11 ... Teeth, 11a ... Inner circumference Surface (radial inner peripheral surface), 12 ... slot, 13u ... U phase winding, 13v ... V phase winding, 13w ... W phase winding, 15 ... fixed cylinder (large diameter part, cylinder), 15a ... first 1 end surface (one side step surface), 15b ... second end surface (other side step surface), 20 ... first rotor core, 20a ... through hole, 21 ... first core base, 21a ... opposite surface, 21b ... opposite surface, 21c ... outer peripheral surface, 22 ... first claw-shaped magnetic pole, 22a, 22b ... end surface, 22c ... tip surface, 23 ... first base, 23a ... surface, 24 ... first magnetic pole portion, 24a ... back surface (radial inner surface) 30 ... second rotor core, 30a ... through hole, 31 ... second core base, 31a ... opposite surface, 31 ... anti-opposing surface, 31c ... outer peripheral surface, 32 ... second claw-shaped magnetic pole, 32a, 32b ... end surface, 32c ... tip surface, 33 ... second base, 33a ... surface, 34 ... second magnetic pole portion, 34a ... back surface ( (Radial inner surface), 40 ... field magnet, 40a, 40b ... side, 40c ... outer peripheral surface, 41 ... through hole, 51, 52 ... first and second back auxiliary magnets, 53, 54 ... first and second Auxiliary auxiliary magnet, 53a, 54a ... radial outer peripheral surface, M ... brushless motor, O ... central axis, f1a, f2a ... radial outer peripheral surface, f1b, f2b ... rear surface.

Claims (5)

A first rotor core having a plurality of first claw-shaped magnetic poles formed at equal intervals in the circumferential direction, a second rotor core having a plurality of second claw-shaped magnetic poles formed at equal intervals in the circumferential direction, and the first and second A field magnet disposed between the rotor cores,
The first and second rotor cores are fixed to a rotation shaft so that the first claw-shaped magnetic poles and the second claw-shaped magnetic poles are alternately arranged in the circumferential direction, and the first claw-shaped magnetic pole is fixed by the field magnet. A rotor configured to function as a first magnetic pole and the second claw-shaped magnetic pole as a second magnetic pole;
A large-diameter portion is formed on the rotating shaft, the field magnet is inserted through the large-diameter portion, and the first rotor core is rotated to a position where the first rotor core is in contact with an axial step surface of the large-diameter portion. A rotor, wherein the rotor is press-fitted into the shaft, and the second rotor core is press-fitted into the rotary shaft to a position where the second rotor core contacts the other step surface in the axial direction of the large-diameter portion. The rotor according to claim 1, wherein
The large-diameter portion has the same axial length as the axial length of the field magnet. The rotor according to claim 1 or 2,
The rotor is characterized in that the rotating shaft is made of a non-magnetic material, and the large diameter portion is formed integrally with the rotating shaft. The rotor according to claim 1 or 2,
The rotating shaft is formed of a non-magnetic material, and the large-diameter portion is formed by integrally forming or press-fitting and fixing a cylindrical body made of a non-magnetic material separate from the rotating shaft to the rotating shaft. Rotor characterized by being.   A motor comprising the rotor according to claim 1.