JP6162567B2 - Inner rotor type motor - Google Patents

Description

  The present invention relates to an inner rotor type motor, and more particularly to an inner rotor type motor capable of suppressing vibration and noise.

  An inner rotor type motor is often used as a drive source in, for example, office equipment and home appliances. This type of inner rotor type motor has demands for higher output (higher efficiency) and lower price. In order to cope with these requirements, a configuration in which a pair of bearings that rotatably support a rotor is held by a bearing housing is proposed in, for example, Patent Documents 1 and 2 below.

  Patent Document 1 listed below discloses a motor including a cover member, two bearings that rotatably support a rotor, and a stator. The cover member includes an outer cylinder portion that supports the stator on the inner surface, an inner cylinder portion that is coaxial with the outer cylinder portion, supports two bearings on the inner surface, a lower end of the outer cylinder portion, and an inner cylinder portion The bottom part which connects a lower end is included. A portion of the inner cylinder portion that holds the two bearings is formed of a thin plate having a uniform thickness.

  The following Patent Document 2 discloses a motor including a housing, two bearings that rotatably support a rotor, and a yoke. Two bearings are fitted on the inner peripheral side of the cylindrical portion of the housing, and the shaft of the rotor is inserted through the two bearings. The yoke covers the housing and fixes the yoke disposed on the tip end side of the cylindrical portion of the housing to the shaft. The portion holding the two bearings in the inner cylindrical portion of the housing is formed of a thin plate having a uniform thickness.

Japanese Patent Application Laid-Open No. 2011-167054 JP 2006-109575 A

  In the techniques of Patent Documents 1 and 2, the coaxiality between the inner diameter surface of the stator and the bearing that rotatably supports the rotor is low. If the coaxiality between the inner diameter surface of the stator and the bearing is low, the variation in the distance between the stator and the rotor becomes large, and it is necessary to set a wide gap between the stator and the rotor in consideration of this variation. As a result, the magnetic efficiency of the motor is reduced and the output of the motor is reduced. In addition, if the coaxiality between the inner diameter surface of the stator and the bearing is low, vibration and noise occur when the rotor rotates.

  The present invention is to solve the above-described problems, and an object thereof is to provide a high-power inner rotor type motor.

  Another object of the present invention is to provide an inner rotor type motor capable of suppressing vibration and noise.

An inner rotor type motor according to one aspect of the present invention includes a rotor including a rotating shaft, a rotor yoke fixed to the rotating shaft, a stator provided on the outer diameter side of the rotor, and a direction along the rotating shaft. And a bearing holding portion that holds the outer diameter portion of each of the first and second bearings and that is arranged and rotatably supports the rotating shaft with respect to the stator. At least a part of the shaft extends in the radial direction between the rotary shaft and the rotor yoke, and the outer diameter surface of the bearing holding portion is in direct contact with the inner diameter surface of the stator core constituting the stator.
Preferably, the inner rotor type motor further includes a housing including a cylindrical portion provided on an outer diameter side of the stator and an extending portion extending in an inner diameter direction from the cylindrical portion, and the stator includes a cylindrical portion of the housing. A stator core fixed to the inner surface, an insulator, and an exciting coil are included.

An inner rotor type motor according to another aspect of the present invention includes a rotor including a rotating shaft, a rotor yoke fixed to the rotating shaft, a stator provided on the outer diameter side of the rotor, and a direction along the rotating shaft. And a bearing holding portion that holds the outer diameter portion of each of the first and second bearings and that is arranged and rotatably supports the rotating shaft with respect to the stator. At least a portion of the first portion extends between the rotary shaft and the rotor yoke in the radial direction, and the radial thickness of the first portion, which is the portion that holds the first bearing in the bearing holding portion, is Unlike the second portion of the radial thickness is a portion for holding the second bearing in the section, a cylindrical portion provided on the outer diameter side of the stator, extending portion extending radially inwardly from the cylindrical portion And a housing including The data includes a stator core fixed to the inner diameter surface of the cylindrical portion of the housing, an insulator, and an exciting coil. The bearing holding portion includes an outer diameter protruding portion that protrudes in the outer diameter direction. Is sandwiched between the extending portion of the housing and the stator core in the direction of the rotation axis.

  Preferably, in the inner rotor type motor, the bearing holding portion includes a rotating shaft direction protruding portion protruding from the housing in the rotating shaft direction.

  In the inner rotor type motor, the bearing holding portion is preferably made of resin.

  In the inner rotor type motor, preferably, the bearing holding portion is made of a material containing at least one metal selected from the group consisting of aluminum, magnesium, and zinc.

  According to the present invention, since the coaxiality between the bearing and the stator inner diameter can be improved, a high output inner rotor type motor can be provided by reducing the gap. Further, according to the present invention, since the coaxiality can be improved, an inner rotor type motor that can suppress vibration and noise can be provided.

It is a top view which shows typically the structure of the motor in the 1st Embodiment of this invention. It is sectional drawing which follows the II-II line of FIG. It is an expanded sectional view showing composition of bearing holder 31 in a 1st embodiment of the present invention. It is sectional drawing which shows typically the structure of the motor in the 2nd Embodiment of this invention. It is sectional drawing which shows typically the structure of the motor in the 3rd Embodiment of this invention. It is sectional drawing which shows typically the structure of the motor in the 4th Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  [First Embodiment]

  FIG. 1 is a plan view schematically showing the configuration of the motor according to the first embodiment of the present invention. 2 is a cross-sectional view taken along line II-II in FIG. Note that FIG. 2 also shows the set-side mounting plate 200 of the external device attached to the motor.

  Referring to FIGS. 1 and 2, the motor of the present embodiment is an inner rotor type motor in which the rotor is provided on the inner diameter side of the stator, and when mounted on an external device (set), the motor It drives the equipment. The motor includes a rotor 10, a stator 20, a bearing holder (an example of a bearing holding portion) 31, a bearing 32 (an example of a first bearing) and 33 (an example of a second bearing), a cover 41, and a housing. 42, a mounting plate 43, a retaining ring 44, a preload spring 45, and a circuit board 46.

  The rotor 10 includes a shaft 11 (an example of a rotating shaft), a rotor yoke 12, and a magnet 13.

  The shaft 11 includes a rotation axis R that is the center of rotation of the rotor 10, and extends in the lateral direction in FIG. 2. The left side (left direction) in FIG. 2 of the shaft 11 is the output shaft side (output shaft direction), and the right side (right direction) in FIG. 2 along the rotation axis R is the non-output shaft side (anti-output shaft direction). It has become.

  The rotor yoke 12 is fixed to the shaft 11. The rotor yoke 12 includes a rotor yoke cylindrical portion 12a and a rotor yoke fixing portion 12b. The rotor yoke cylindrical portion 12a extends in the direction of the rotation axis R at a distance from the shaft 11. The rotor yoke fixing portion 12b extends in the inner diameter direction at the end on the counter-output shaft side of the rotor yoke cylindrical portion 12a. The rotor yoke fixing portion 12 b fixes the rotor yoke cylindrical portion 12 a to the shaft 11.

  The magnet 13 has a cylindrical shape and is fixed at a position facing the stator 20 on the outer diameter surface of the rotor yoke 12. The outer peripheral surface of the magnet 13 is magnetized. N poles and S poles are alternately formed on the outer peripheral surface of the magnet 13 along the circumferential direction.

  The stator 20 includes a stator core 21, an excitation coil 22 (an example of a coil), and an insulator 23.

  The stator core 21 includes an annular back yoke 21a and a plurality of teeth 21b. Each of the plurality of teeth 21b is provided at equal intervals along the circumferential direction of the back yoke 21a, and protrudes from the inner diameter surface of the back yoke 21a in the inner diameter direction.

  The exciting coil 22 is wound around each of the plurality of teeth 21b with the insulator 23 interposed therebetween.

  The insulator 23 insulates the stator core 21 and the exciting coil 22 from each other.

  The cover 41 includes a cover cylindrical portion 41a, a cover end portion 41b, and an insertion hole 41c. The cover cylindrical portion 41a extends in the direction of the rotation axis R. The cover end 41b extends in the inner diameter direction at the end on the counter-output shaft side of the cover cylindrical portion 41a. The insertion hole 41c is formed at the center of the cover end 41b.

  The housing 42 includes a housing cylindrical portion 42a (an example of a cylindrical portion), a housing extending portion 42b (an example of an extending portion), and a fixing hole 42c. The housing cylindrical portion 42 a extends in the direction of the rotation axis R and is provided on the outer diameter side of the stator 20. A back yoke 21a of the stator core 21 is fixed to the inner diameter surface of the housing cylindrical portion 42a. The housing extending part 42b extends in the inner diameter direction from the housing cylindrical part 42a at the output shaft side end of the housing cylindrical part 42a. The fixing hole 42c is formed at the center of the housing extension 42b.

  The mounting plate 43 includes a plate portion 43a and a fixing hole 43b. The plate part 43a has a disk shape. The fixing hole 43b is formed at the center of the plate portion 43a.

  The retaining ring 44 is fixed to the shaft 11 at a position closer to the output shaft than the bearing 32. The retaining ring 44 positions a preload spring 45 that applies preload to the bearings 32 and 33.

  The preload spring 45 is disposed between the retaining ring 44 and the bearing 32, and biases the bearing 32 in the direction opposite to the output shaft. The preload spring 45 is made of a leaf spring, for example.

  The circuit board 46 is attached to the end of the stator 20 opposite to the output shaft. The circuit board 46 is formed with a circuit for controlling the rotation of the rotor 10.

  The bearing holder 31 holds the outer diameter portions of the bearings 32 and 33. The bearings 32 and 33 are press-fitted and fixed to the bearing holder 31. As described above, by housing the two bearings 32 and 33 in one bearing holder 31, the two bearings are coaxial compared to a general structure in which bearings are separately housed in the rear housing and the front housing. The degree of concentricity can be easily improved. As a result, the coaxiality between the inner diameter of the stator 21 and the bearings 32 and 33 is improved, and noise due to vibration of the rotor 10 can be reduced. In addition, the assembly work of the motor becomes easy and the cost can be reduced.

  The bearings 32 and 33 are arranged side by side in the direction along the rotation axis R, and the bearing 32 is arranged closer to the output shaft than the bearing 33. Each of the bearings 32 and 33 rotatably supports the shaft 11 with respect to the stator 20 and constitutes a ball bearing with the shaft 11. The bearings 32 and 33 may be ball bearings or may be sliding bearings, for example.

  FIG. 3 is an enlarged cross-sectional view showing the configuration of the bearing holder 31 in the first embodiment of the present invention. (A) is sectional drawing which shows the relationship between the bearing holder 31 and the bearings 32 and 33. FIG. FIG. 3B is an enlarged cross-sectional view in the vicinity of part A in FIG.

  Referring to FIG. 3, bearing holder 31 is provided at a position on the inner diameter side of stator 20, housing 42, and mounting plate 43. The bearing holder 31 includes a holder main body 101, an anti-output axial direction extending portion 102, and an insertion hole 103.

  The holder main body 101 has an outer diameter larger than the outer diameter of the non-output-axis-direction extending portion 102. The counter-output shaft direction extending portion 102 extends from the counter-output shaft side end portion of the holder body 101 in the counter-output shaft direction. The insertion hole 103 is formed at the center of each of the holder main body 101 and the non-output axial direction extending portion 102. Bearings 32 and 33 are press-fitted into the insertion hole 103.

  The counter-output shaft direction extending portion 102 extends between the shaft 11 and the rotor yoke 12 in the radial direction. Thereby, a part of the bearing holder 31 is accommodated in the space on the inner diameter side of the rotor yoke 12 in a non-contact manner, and the rotor yoke 12 and the bearing holder 31 overlap each other in the radial direction. ) Can be reduced, and the motor can be miniaturized.

  The holder main body 101 includes an output shaft direction protruding portion 101a, an outer diameter surface 101b, an outer diameter surface 101c, and an outer diameter surface 101e.

  The output shaft direction protruding portion 101a (an example of the rotating shaft direction protruding portion) protrudes from the housing 42 and the mounting plate 43 in the output shaft direction. The output shaft direction protruding portion 101a constitutes an inlay when the motor is attached to the set side attachment plate 200 (FIG. 2) of the external device.

  The outer diameter surface 101b is an outer diameter surface located at the output shaft side end of the holder body 101. The outer diameter surface 101b is opposed to the inner diameter surfaces of the fixing holes 42c and 43b with a space therebetween. The outer diameter surface 101b may be in contact with the inner diameter surfaces of the fixing holes 42c and 43b. In this case, the bearing holder 31 is fixed to the inner diameter surfaces of the housing 42 (housing extending portion 42 b) and the mounting plate 43.

  The outer diameter surface 101c is an outer diameter surface located on the side opposite to the output shaft of the outer diameter surface 101b, and has a diameter larger than the diameter of each of the outer diameter surfaces 101b and 101e. A portion 104 (an example of an outer diameter protruding portion) constituting the outer diameter surface 101 c of the bearing holder 31 protrudes in the outer diameter direction from other portions constituting the holder main body 101. The portion 104 is sandwiched between the stator 20 (stator core 21) and the housing 42 in the direction of the rotation axis R. Thereby, the bearing holder 31 is restrained from moving in the direction of the rotation axis R, and stably holds the bearings 32 and 33.

  The outer diameter surface 101c faces the insulator 23 with a gap. The outer diameter surface 101c may be in contact with the insulator 23.

  The outer diameter surface 101e is an outer diameter surface located on the side opposite to the output shaft of the outer diameter surface 101c (the end on the side opposite to the output shaft of the holder body 101), and has a diameter smaller than the diameter of the outer diameter surface 101c. Yes. The outer diameter surface 101 e is in direct contact (fitting) with the inner diameter surface of each of the plurality of teeth 21 b in the stator core 21. Thereby, the bearing holder 31 is fixed to the inner diameter side end portion of the stator 20. Thus, the bearing holder 31 can be positioned using the inner diameter surface of the stator 20 by bringing the outer diameter surface 101 e of the bearing holder 31 into direct contact with the inner diameter surface of the stator 20.

  The holder main body 101 has a fixed portion 111 at the end on the side opposite to the output shaft. The fixed portion 111 is a portion that holds the bearing 32, and the bearing 32 is fixed to the inner diameter surface of the insertion hole 103 of the fixed portion 111. The non-output shaft direction extending portion 102 has a fixed portion 112 at an end portion on the counter output shaft side. The fixed portion 112 is a portion that holds the bearing 33, and the bearing 33 is fixed to the inner diameter surface of the insertion hole 103 of the fixed portion 112.

  The radial thickness W1 of the fixed portion 111 and the radial thickness W2 of the fixed portion 112 are different from each other. In the present embodiment, thickness W1 is greater than thickness W2.

  In the present embodiment, the diameter of the insertion hole 103 from the end portion on the side opposite to the output shaft of the bearing holder 31 to the fixed portion 111 decreases monotonously. The diameter (outer diameter of the bearing 32) D1 of the insertion hole 103 of the fixed part 111 is smaller than the diameter (outer diameter of the bearing 33) D2 of the insertion hole 103 of the fixed part 112. The diameter D1 and the diameter D2 may be different from each other as described above, or may be equal.

  The bearing holder 31 is made of, for example, resin. The bearing holder 31 may be a molded product made of a substance containing at least one metal selected from the group consisting of aluminum, magnesium, and zinc. The material of the bearing holder 31 may be selected in consideration of necessary strength and accuracy, cost, and the like.

  According to the present embodiment, since the inner diameter surface of stator 20 and outer diameter surface 101e of bearing holder 31 are in contact, bearing holder 31 and bearings 32 and 33 are positioned with reference to the inner diameter surface of stator 20. The coaxiality between the inner diameter surface of the stator 20 and the bearings 32 and 33 can be improved.

  In addition, the radial thickness W1 of the fixing portion 111 that is a portion for fixing the bearing 32 and the radial thickness W2 of the fixing portion 112 that is a portion for fixing the bearing 33 are different from each other. Each of the thicknesses W1 and W2 can be freely set according to the applied load. Thereby, even when the motor length is long, the bearing holder 31 can be prevented from being deformed by a load applied to the bearing, and the coaxiality between the inner diameter surface of the stator 20 and the bearings 32 and 33 can be improved. Can do. Moreover, since the thickness of the bearing holder 31 can be increased, the strength is improved and a highly reliable inner rotor type motor can be provided.

  When the coaxiality between the inner diameter surface of the stator 20 and the bearings 32 and 33 is improved, the coaxiality between the stator 20 and the rotor 10 is improved. Thereby, the dispersion | variation in the distance of the stator 20 and the rotor 10 becomes small, and the clearance gap between the stator 20 and the rotor 10 can be set narrowly. As a result, the magnetic efficiency of the motor can be improved, resulting in a high output motor. In addition, since the coaxiality between the inner diameter surface of the stator and the bearing is improved, vibration and noise during rotation of the rotor can be suppressed.

  If the motor does not need to have a high output, the number of turns of the coil can be reduced, the magnet can be made smaller, and the number of stator cores can be reduced (the motor length can be shortened). Miniaturization can be achieved.

  Further, when the motor is attached to the external device, the output shaft direction protruding portion 101a becomes a convex inlay, so that the output shaft direction protruding portion 101a and the concave inlay provided on the set side mounting plate 200 side of the external device are provided. , The external device can be accurately positioned.

  Further, since the diameter of the insertion hole 103 from the end portion on the side opposite to the output shaft of the bearing holder 31 to the fixed portion 111 is monotonically reduced, the opening at the end on the side opposite to the output side of the insertion hole 103 when the bearings 32 and 33 are assembled. The bearings 32 and 33 can be inserted into the insertion hole 103 from right to left in FIG.

  [Second Embodiment]

  FIG. 4 is a cross-sectional view schematically showing the configuration of the motor in the second embodiment of the present invention. In addition, subsequent FIGS. 4-6 has shown sectional drawing in alignment with the II-II line | wire of FIG.

  Referring to FIG. 4, the motor according to the present embodiment is different from the first embodiment in the shape of bearing holder 31. In the bearing holder 31, the diameter D 1 of the insertion hole 103 of the fixing part 111 that is a part for fixing the bearing 32 and the diameter D 2 of the insertion hole 103 of the fixing part 112 that is a part for fixing the bearing 33 are both fixed parts 111. It is larger than the diameter D3 of the thick portion 113 which is a portion between the fixed portion 112 and the fixed portion 112.

  The preload spring 45 is disposed between the bearing 32 and the bearing 33 and urges the bearing 32 in the output shaft direction.

  Since the configuration of the motor other than the above is the same as the configuration of the motor according to the first embodiment shown in FIGS. 1 to 3, the same reference numerals are given to the same members, and the description thereof will not be repeated. .

  According to the present embodiment, since the diameter D1 of the insertion hole 103 of the fixing portion 111 and the diameter D2 of the insertion hole 103 of the fixing portion 112 are both larger than the diameter D3 of the thick portion 113, the bearings 32 and 33 , The bearing 32 is inserted into the insertion hole 103 from the left to the right in FIG. The bearing 33 can be inserted into the insertion hole 103 from the right to the left in FIG. In addition, since the thickness W3 of the thick portion 113 can be increased, the strength of the bearing holder 31 can be improved.

  [Third Embodiment]

  FIG. 5 is a cross-sectional view schematically showing the configuration of the motor in the third embodiment of the present invention.

  Referring to FIG. 5, the motor according to the present embodiment is different from the first embodiment in the shape of bearing holder 31. The diameter of the insertion hole 103 from the output shaft side end portion of the bearing holder 31 to the fixed portion 112 is monotonously decreasing. The diameter (outer diameter of the bearing 32) D1 of the insertion hole 103 of the fixed portion 111 is larger than the diameter (outer diameter of the bearing 33) D2 of the insertion hole 103 of the fixed portion 112. The radial thickness W1 of the fixed portion 111 is larger than the radial thickness W2 of the fixed portion 112.

  The preload spring 45 (in this embodiment, a coil spring is illustrated as the preload spring 45) is disposed between the bearing 32 and the bearing 33, and biases the bearing 33 in the counter-output shaft direction.

  Since the configuration of the motor other than the above is the same as the configuration of the motor according to the first embodiment shown in FIGS. 1 to 3, the same reference numerals are given to the same members, and the description thereof will not be repeated. .

  According to the present embodiment, since the diameter of the insertion hole 103 from the output shaft side end of the bearing holder 31 to the fixed part 112 is monotonously reduced, the output side of the insertion hole 103 when the bearings 32 and 33 are assembled. The bearings 32 and 33 can be inserted into the insertion hole 103 from the left to the right in FIG.

  [Fourth Embodiment]

  FIG. 6 is a cross-sectional view schematically showing the configuration of the motor in the fourth embodiment of the present invention.

  Referring to FIG. 6, the motor in the present embodiment is different in the shape of bearing holder 31 from that in the first embodiment. The diameter of the insertion hole 103 from the end on the side opposite to the output shaft of the bearing holder 31 to the fixed portion 111 is constant. The diameter D1 of the insertion hole 103 of the fixing part 111 is the same as the diameter D2 of the insertion hole 103 of the fixing part 112. The bearings 32 and 33 have the same outer diameter. Further, instead of the retaining ring, a spacer ring 47 is disposed together with the preload spring 45 between the bearing 32 and the bearing 33. The preload spring 45 biases the bearing 32 in the output shaft direction. Further, the teeth portion 21b and the back yoke portion 21a are not separated but are integrated.

  Since the configuration of the motor other than the above is the same as the configuration of the motor according to the first embodiment shown in FIGS. 1 to 3, the same reference numerals are given to the same members, and the description thereof will not be repeated. .

  According to the present embodiment, since the inner diameter of the bearing holder 31 is constant, the processing and molding of the bearing holder 31 are facilitated, and the assembly work of the bearing can be easily performed.

  [Others]

  The above embodiments can be combined as appropriate. The stop ring and the preload spring may be omitted. The radial thickness of the bearing holder may be designed according to the required strength.

  The above-described embodiment is to 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.

10 Rotor 11 Shaft (Example of rotating shaft)
DESCRIPTION OF SYMBOLS 12 Rotor yoke 12a Rotor yoke cylindrical part 12b Rotor yoke fixing | fixed part 13 Magnet 20 Stator 21 Stator core 21a Back yoke 21b Teeth 22 Excitation coil (an example of a coil)
23 Insulator 31 Bearing holder (an example of a bearing holding portion)
32, 33 Bearing (an example of first and second bearings)
41 Cover 41a Cover cylindrical portion 41b Cover end portion 41c, 103 Insertion hole 42 Housing 42a Housing cylindrical portion 42b Housing extension 42c Housing fixing hole 43 Mounting plate 43a Plate portion 43b Mounting plate fixing hole 44 Retaining ring 45 Preload spring 46 Circuit board 47 Spacer 101 Holder body 101a Output shaft direction protruding portion of holder body (an example of rotating shaft direction protruding portion)
101b, 101c, 101e Outer diameter surface of holder main body 102 Anti-output axial direction extension part 104 Part of bearing holder (an example of outer diameter direction protrusion part)
111, 112 fixing part (an example of the first part and the second part in the bearing holding part)
113 Thick part (an example of the third part of the bearing holding part)
200 External device set side mounting plate D1, D2, D3 Diameter R Rotating shaft W1, W2, W3 Thickness

Claims (6)

A rotor including a rotating shaft and a rotor yoke fixed to the rotating shaft;
A stator provided on the outer diameter side of the rotor;
First and second bearings arranged side by side in a direction along the rotation axis and rotatably supporting the rotation axis with respect to the stator;
A bearing holding portion that holds an outer diameter portion of each of the first and second bearings,
At least a part of the bearing holding portion extends between the rotating shaft and the rotor yoke in the radial direction,
An inner rotor type motor in which an outer diameter surface of the bearing holding portion is in direct contact with an inner diameter surface of a stator core constituting the stator. A housing including a cylindrical portion provided on the outer diameter side of the stator and an extending portion extending in the inner diameter direction from the cylindrical portion;
2. The inner rotor type motor according to claim 1, wherein the stator includes the stator core fixed to an inner diameter surface of the cylindrical portion of the housing, an insulator, and an excitation coil. A rotor including a rotating shaft and a rotor yoke fixed to the rotating shaft;
A stator provided on the outer diameter side of the rotor;
First and second bearings arranged side by side in a direction along the rotation axis and rotatably supporting the rotation axis with respect to the stator;
A bearing holding portion that holds an outer diameter portion of each of the first and second bearings,
At least a part of the bearing holding portion extends between the rotating shaft and the rotor yoke in the radial direction,
The radial thickness of the first portion that is the portion that holds the first bearing in the bearing holding portion is the radial direction of the second portion that is the portion that holds the second bearing in the bearing holding portion. Unlike the thickness,
A housing including a cylindrical portion provided on the outer diameter side of the stator and an extending portion extending in the inner diameter direction from the cylindrical portion;
The stator includes a stator core fixed to an inner diameter surface of the cylindrical portion of the housing, an insulator, and an excitation coil.
The bearing holding portion includes an outer diameter direction protruding portion protruding in an outer diameter direction,
The outer-diameter protruding portion is an inner rotor type motor that is sandwiched between the extending portion of the housing and the stator core in the rotation axis direction . 4. The inner rotor type motor according to claim 2 , wherein the bearing holding portion includes a rotating shaft direction protruding portion protruding from the housing in the rotating shaft direction. 5. The bearing holder is made of resin, the inner rotor type motor according to any one of claims 1-4. The bearing holder is aluminum, magnesium, and at least one metal which is of a material including, an inner rotor type motor according to any one of claims 1-4 selected from the group consisting of zinc.

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