JP2013031261A - Electric motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric motor enabling effective reduction in the size thereof.SOLUTION: This electric motor includes: a yoke 5; a rotating shaft 3 which has one end rotatably supported by a sliding bearing 18 installed in the yoke 5; and an armature core 8 which is mounted on the rotating shaft 3 and has a plurality of teeth 12 radially extending toward the radial direction. An armature coil 9 is wound around each tooth 12 in a concentrated winding method, and the sliding bearing 18 is disposed so as to face a radial inner side from a coil end 9a of each armature coil 9 located on the side of an axial end face of the armature core 8.

Description

  The present invention relates to an electric motor mounted on a vehicle, for example.

  For example, among these types of electric motors, there are wiper motors for automobiles. The wiper motor has a motor part and a speed reduction part assembled together. In the motor section, an armature (electric element) around which a coil is wound is rotatably arranged inside a bottomed cylindrical yoke (yoke housing) having a plurality of magnetic poles on the inner peripheral surface.

The armature has a rotating shaft, an armature core (electron core) that is externally fixed to the rotating shaft, and a commutator (commutator). A bearing for rotatably supporting the rotary shaft is provided at the bottom of the yoke that rotatably supports the armature.
The armature core has a plurality of teeth arranged radially, and coils are wound around these teeth by, for example, a distributed winding method. Moreover, the commutator has a plurality of segments arranged in the circumferential direction, and a terminal portion of the coil is connected to each of the segments.

In addition, a brush electrically connected to an external power source such as a battery is slidably contacted with the segment, and a current is supplied to the coil via the brush and the segment. When a current is supplied to the coil, a magnetic field is generated in the teeth around which the coil is wound. A magnetic repulsive force or attractive force is generated between the magnetic field and the magnetic pole of the yoke, whereby the armature rotates. As the armature rotates, the segments in sliding contact with the brush are sequentially changed, so that the direction of the current flowing in the coil is switched, so-called rectification is performed, and the armature rotates continuously.
Here, the bearing provided at the bottom of the yoke is projected outward in the axial direction so as to avoid interference with the coil end of each coil existing on the axial end face side of the armature core ( For example, see Patent Document 1).

JP 2010-226847 A

  By the way, motors mounted on vehicles such as wiper motors are always required to be downsized due to demands for improving vehicle mountability. However, in the above-described prior art, since the bearing provided at the bottom of the yoke protrudes toward the outside in the axial direction, there is a problem that it is difficult to miniaturize the motor.

  The present invention has been made in view of the above-described circumstances, and provides an electric motor that can be effectively downsized.

  In order to solve the above-described problems, the invention described in claim 1 is attached to a motor case, a rotary shaft that is rotatably supported at both ends by a bearing provided in the motor case, and the rotary shaft. An armature core having a plurality of teeth extending radially in the radial direction, and a coil of each coil existing on the axial end face side of the armature core, wherein a coil is wound around each tooth by a concentrated winding method. At least one of the bearings is disposed so as to face the inner side in the radial direction from the end.

  Thus, by winding a coil around each tooth by a concentrated winding method, it is possible to eliminate a connecting wire between the teeth. Moreover, since the space factor of a coil can be improved, the length of the radial direction of teeth can be set short by this amount. For this reason, if the diameter of the armature core is the same as that of the prior art, it is possible to secure a large space inside the teeth in the armature core in the radial direction as long as the length of the teeth in the radial direction can be set short. By arranging the bearing in this space, the shaft of the electric motor can be shortened, and the electric motor can be effectively downsized.

  The invention described in claim 2 is characterized in that at least one of the bearings arranged at both ends of the rotating shaft is a rolling bearing.

  By comprising in this way, an armature can be rotated efficiently. Since the arm can be rotated efficiently, the performance of the armature itself can be reduced. As a result, the armature can be reduced in size. Therefore, the electric motor can be reduced in size.

  According to a third aspect of the present invention, the motor case has a bottomed cylindrical yoke having a plurality of magnetic poles, and a bearing housing protruding inward is formed at the bottom of the yoke. One of the bearings is supported on the base.

  With this configuration, the shaft of the electric motor can be shortened with a simple structure.

  The invention described in claim 4 is characterized in that a hole penetrating in the axial direction is formed radially inside the teeth of the armature core.

  In this way, even when holes are formed radially inward from the teeth of the armature core, the coils are wound around the teeth by the concentrated winding method. No crossover is routed. For this reason, since the hole of an armature core is exposed reliably, the air in an electric motor convects effectively through this hole. Thereby, cooling of an electric motor is accelerated | stimulated and motor efficiency improves. Therefore, if the motor efficiency is equivalent to the conventional motor efficiency, the size of the electric motor can be reduced.

  According to the present invention, by winding a coil around each tooth by a concentrated winding method, it is possible to eliminate a connecting wire between the teeth. Moreover, since the space factor of a coil can be improved, the length of the radial direction of teeth can be set short by this amount. For this reason, if the diameter of the armature core is the same as that of the prior art, it is possible to secure a large space inside the teeth in the armature core in the radial direction as long as the length of the teeth in the radial direction can be set short. By arranging the bearing in this space, the shaft of the electric motor can be shortened, and the electric motor can be effectively downsized.

It is a longitudinal cross-sectional view of the motor with a reduction gear in 1st Embodiment of this invention. It is the A section enlarged view of FIG. It is a top view of the electric motor in a 1st embodiment of the present invention. It is a top view of the brush accommodating part in subject 1 embodiment of this invention. FIG. 5 is a longitudinal sectional view of an electric motor according to a second embodiment of the present invention. It is a longitudinal cross-sectional view of the electric motor in 3rd Embodiment of this invention. It is a longitudinal cross-sectional view of the electric motor in 4th Embodiment of this invention.

(First embodiment)
(Motor with reduction gear)
Next, 1st Embodiment of this invention is described based on drawing.
1 is a longitudinal sectional view of a motor 1 with a speed reducer to which an electric motor 2 according to the present invention is applied, FIG. 2 is an enlarged view of a portion A in FIG. 1, and FIG. FIG.
As shown in FIGS. 1 to 3, a motor 1 with a speed reducer is used for driving a wiper of an automobile, for example, and includes an electric motor 2 and a speed reduction mechanism 4 connected to a rotating shaft 3 of the electric motor 2. And. The electric motor 2 includes a bottomed cylindrical yoke 5 and an armature 6 rotatably provided in the yoke 5.

The cylindrical portion 53 of the yoke 5 is formed in a substantially cylindrical shape, and four segment-type permanent magnets 7 are disposed on the inner peripheral surface of the cylindrical portion 53.
A bearing housing 19 is formed on the bottom wall (end portion) 51 of the yoke 5 so as to protrude inward in the axial direction at the radial center. More specifically, by pressing the bottom wall 51 of the yoke 5, a substantially ring-shaped wall rising from the bottom wall 51 toward the inner side in the axial direction is formed, and this wall is used as the bearing housing 19.
A sliding bearing 18 for rotatably supporting one end of the rotary shaft 3 is press-fitted and fixed to the bearing housing 19. The sliding bearing 18 has a centering function of the rotating shaft 3.

  An outer flange portion 52 is provided in the opening portion 53 a of the cylindrical portion 53. Bolt holes (not shown) are formed in the outer flange portion 52. A bolt (not shown) is inserted into the bolt hole and screwed into a bolt hole (not shown) formed in a gear housing 23 (described later) of the speed reduction mechanism 4, whereby the yoke 5 is fastened and fixed to the speed reduction mechanism 4.

  The armature 6 includes an armature core 8 that is externally fixed to the rotating shaft 3, an armature coil 9 that is wound around the armature core 8, and a commutator 10 that is disposed on the other end side (left side in FIG. 3) of the rotating shaft 3. And. The armature core 8 is disposed so that the end surface on one end side (right side in FIG. 3) of the rotary shaft 3 is close to the bearing housing 19 formed on the bottom wall 51 of the yoke 5. The armature core 8 is formed by laminating a plate of magnetic material punched by pressing or the like in the axial direction (laminated core), or pressure-molding soft magnetic powder (a dust core). The core body 11 has a substantially cylindrical shape.

  The diameter of the core body 11 is set to be slightly larger than the diameter of the bearing housing 19 formed on the bottom wall 51 of the yoke 5. A through-hole 11a for press-fitting the rotary shaft 3 is formed at a substantially central portion of the core body 11 in the radial direction. In addition, on the outer peripheral portion of the core body 11, six radial teeth 12 that are substantially T-shaped in a plan view in the axial direction are provided radially. By providing teeth 12 radially on the outer peripheral portion of the core body 11, six dovetail-shaped slots 13 are formed between adjacent teeth 12. The armature coils 9 are inserted into the slots 13, and the armature coils 9 are wound around the teeth 12 by a concentrated winding method.

  Here, the core main body 11 is formed with six circular holes 11b having a circular cross section penetrating in the axial direction at positions corresponding to the roots of the teeth 12 along the circumferential direction. More specifically, between the through hole 11a of the core body 11 and the tooth 12, there is a hole slightly closer to the through hole 11a than the substantially radial center between the through hole 11a and the root of the tooth 12. 11b is formed. The air holes 11b are for accelerating convection of air inside the electric motor 2 and suppressing temperature rise of the electric motor 2.

  Here, as shown in detail in FIG. 3, since the armature coil 9 is wound around each tooth 12 by the concentrated winding method, the crossover of the armature coil 9 straddling between adjacent teeth 12 is eliminated. That is, the overlap of the coil end 9a of the armature coil 9 existing at the axial end of the armature core 8 is reduced as compared with the case where the armature coil 9 is wound by the distributed winding method. For this reason, the hole 11b formed in the core main body 11 is exposed without the axial direction end part of the core main body 11 of the armature core 8 being covered with the armature coil 9.

  Further, since the diameter of the core body 11 of the armature core 8 is set to be slightly larger than the diameter of the bearing housing 19 formed on the bottom wall 51 of the yoke 5, the armature is formed around the bearing housing 19. The coil end 9a of the coil 9 is present. In addition, the armature core 8 is disposed so as to be close to the bearing housing 19 formed on the bottom wall 51 of the yoke 5. For this reason, the bearing housing 19 and the sliding bearing 18 will be in the state arrange | positioned so that it may face the radial inside of the coil end 9a.

  As shown in FIGS. 1 and 2, a commutator 10 is fitted and fixed to the other end side of the rotary shaft 3 from the armature core 8. Eighteen segments 15 made of a conductive material are attached to the outer peripheral surface of the commutator 10. The segment 15 is made of a plate-like metal piece that is long in the axial direction, and is fixed in parallel at equal intervals along the circumferential direction while being insulated from each other.

In addition, a riser 16 that is bent so as to be folded back to the outer diameter side is integrally formed at the end of each segment 15 on the armature core 8 side. A terminal portion of the armature coil 9 is wound around the riser 16 and fixed by fusing or the like. Thereby, the segment 15 and the armature coil 9 corresponding to this are conducted.
Note that connection lines (not shown) are wound around the risers 16 corresponding to the segments 15 having the same potential, and the connection lines (not shown) are fixed to the risers 16 by fusing. Thereby, the segments 15 having the same potential are short-circuited.

  The commutator 10 configured in this way is in a state of facing the gear housing 23 of the speed reduction mechanism 4. The gear housing 23 is formed in a substantially box shape having an opening 42 a on one surface, and is made of an aluminum die-cast housing body 42 that houses the gear group 41 of the speed reduction mechanism 4, and a resin that closes the opening 42 a of the housing body 42. And the bottom plate 43. On the side of the electric motor 2 of the housing main body 42, the brush housing portion 22 is integrally formed, and the commutator 10 of the electric motor 2 is exposed here.

(Brush storage part)
FIG. 4 is a plan view of the brush storage unit 22.
As shown in the figure, the brush housing portion 22 is formed in a concave shape on the electric motor 2 side of the gear housing 23. The peripheral wall 30 of the brush housing part 22 is formed in a substantially oval cross section, and is composed of a flat wall 30a and an arc wall 30b.

  A cover 33 formed in a cylindrical shape having a substantially oval cross section is provided inside the brush housing portion 22 so as to correspond to the inside. The cover 33 also has a flat wall 33a and an arc wall 33b. Further, a holder stay 34 formed so as to correspond to the cover 33 is provided inside the cover 33. The holder stay 34 is fastened and fixed to the side wall 42 b of the housing body 42 by bolts 35.

  The holder stay 34 is provided with brush holders 36 at three locations in the circumferential direction. In the brush holder 36, the brushes 21 are housed in such a manner that they can be moved in and out in a state where the brushes 21 are urged through the springs S, respectively. Since the tips of the brushes 21 are urged by the spring S, they are in sliding contact with the segment 15 of the commutator 10. The brush 21 is electrically connected to an external power source (not shown), for example, a battery mounted on an automobile. The commutator 10 can be supplied with power from an external power source (not shown).

  The brush 21 includes a low-speed brush 21a and a high-speed brush 21b connected to the anode side, and a common brush 21c commonly used for the low-speed brush 21a and the high-speed brush 21b and connected to the cathode side. It is configured. The low speed brush 21a and the common brush 21c are disposed at an electrical angle of 180 °, that is, at a mechanical angle of 90 ° in the circumferential direction. On the other hand, the high speed brush 21b is spaced apart from the low speed brush 21a by an angle α in the circumferential direction. In the present embodiment, the common brush 21c is described as the cathode side, and the low speed brush 21a and the high speed brush 21b are described as the anode side. However, the anode side and the cathode side may be reversed.

  Here, the segments 15 having the same potential of the commutator 10, that is, the segments 15 facing each other around the rotation shaft 3 are short-circuited by the connection line 17, so that the segment to which the brush 21 is not in sliding contact is also fed. It becomes possible to do. Therefore, the high-speed brush 21b exists at a position advanced by an angle θ relative to the low-speed brush 21a.

(Deceleration mechanism)
As shown in FIG. 1, a gear group 41 is accommodated in a housing body 42 in the gear housing 23 to which the electric motor 2 is attached. The gear group 41 includes a worm shaft 25 connected to the rotary shaft 3 of the electric motor 2, a pair of stepped gears 26 and 26 that mesh with the worm shaft 25, and a spur gear 27 that meshes with the stepped gear 26. Has been.

One end of the worm shaft 25 is connected to the rotating shaft 3, and the other end is rotatably supported by the housing body 42. The connecting portion 24 between the worm shaft 25 and the rotary shaft 3, that is, the other end of the rotary shaft 3 is rotatably supported by the rolling bearing 32. The rolling bearing 32 is provided on the bottom wall 31 of the brush storage portion 22 formed in the housing main body 42.
Further, the worm shaft 25 has a first screw portion 25a and a second screw portion 25b that are opposite to each other. The first screw portion 25a and the second screw portion 25b are formed in one or two strips. However, you may form the 1st screw part 25a and the 2nd screw part 25b in three or more strips.

A pair of stepped gears 26 and 26 are disposed on both sides of the worm shaft 25, and a pair of stepped gears 26 and 26 are engaged with the first screw portion 25a and the second screw portion 25b, respectively. ing.
The pair of stepped gears 26 is formed by integrally forming a worm wheel 28 that meshes with the worm shaft 25 and a small-diameter gear 29 that has a smaller diameter than the worm wheel 28. An idler shaft 61 is press-fitted into the center of the stepped gear 26 in the radial direction. The idler shaft 61 protrudes on the side opposite to the small-diameter gear 29, and the protruding end portion 61 a is rotatably supported by the housing body 42. On the other hand, the tip of the small-diameter gear 29 existing at the end opposite to the end 61 a of the idler shaft 61 is rotatably supported by the bottom plate 43.

  As described above, both ends of the pair of stepped gears 26 are pivotally supported by the housing main body 42 and the bottom plate 43. The pair of stepped gears 26 and 26 rotate in the same direction, and transmit the rotation of the worm shaft 25 to the spar gear 27. That is, the worm shaft 25 and the pair of stepped gears 26 and 26 constitute a so-called Marshall mechanism, and the thrust force applied to the worm shaft 25 is offset by the pair of stepped gears 26 and 26. It has become.

  The spur gear 27 meshes with the small diameter gear 29 of the stepped gear 26. At the center of the spur gear 27 in the radial direction, a boss portion 65 is formed to protrude toward the bottom plate 43 side. The boss 65 is rotatably supported on the bottom plate 43. An output shaft 62 is press-fitted into the boss portion 65. The output shaft 62 protrudes from the bottom wall (end portion) 42 c of the housing body 42. On the bottom wall 42c of the housing main body 42, a boss portion 63 is formed projecting outward at a portion corresponding to the output shaft 62. The boss portion 63 is provided with a slide bearing 64 for rotatably supporting the output shaft 62.

A portion of the output shaft 62 that protrudes from the housing main body 42 is formed with a tapered portion 66 that gradually tapers toward the tip. A serration 67 is formed in the tapered portion 66. Thereby, for example, an external mechanism for driving a wiper or the like and the output shaft 62 can be connected.
A connector 68 projects from the side wall 42 b of the housing body 42 along the axial direction of the rotary shaft 3. The connector 68 is connected to a control device (not shown), and supplies electric power from an external power source (not shown) to the electric motor 2.

  A substrate 71 is disposed on the inner surface 43 a of the bottom plate 43 that closes the opening 42 a of the housing body 42. The board 71 is provided with a terminal 72 for electrically connecting the connector 68 and the electric motor 2. The substrate 71 is provided with contactors 73a and 73b. The contactors 73 a and 73 b are sliding contacts for detecting the rotational position of the spur gear 27. A contact plate (not shown) is provided at a portion where the contactors 73a and 73b of the spur gear 27 are in sliding contact.

  Then, as the spur gear 27, that is, the output shaft 62 rotates, the contact position between the contactors 73a and 73b and the contact plate (not shown) changes or contacts / non-contacts, so that the output shaft 62 rotates. The position can be detected. Signals detected by the contactors 73a and 73b are output to a control device (not shown) via the terminal 72, and rotation control of the electric motor 2 is performed.

(effect)
Therefore, according to the above-described first embodiment, the armature coil 9 is wound around each tooth 12 of the armature core 8 by the concentrated winding method, thereby eliminating the connecting wire of the armature coil 9 straddling the teeth 12. be able to. Moreover, since the space factor of the armature coil 9 can be improved, the length of the teeth 12 in the radial direction can be set shorter. For this reason, if the diameter of the armature core 8 is the same as the conventional one, the space in the radial direction of the teeth 12 in the armature core 8, that is, the diameter of the core body 11 can be set to the extent that the radial length of the teeth 12 can be set short. Can be set large. The shaft of the electric motor 2 can be easily shortened by arranging the bearing housing 19 (sliding bearing 18) so as to face the radially inner side of the coil end 9a of the armature coil 9. The motor 2 can be effectively downsized.

  Further, by eliminating the connecting wire of the armature coil 9, the end portion in the axial direction of the core body 11 of the armature core 8 is not covered with the armature coil 9, and the hole 11b formed in the core body 11 is exposed. For this reason, convection of air inside the electric motor 2 can be promoted. For this reason, the temperature rise of the electric motor 2 can be suppressed and motor efficiency can be improved. By improving the motor efficiency, it is possible to reduce the performance of the armature 6 itself if the motor efficiency is the same as the conventional one. As a result, the armature 6 can be reduced in size, and the electric motor 2 can be reduced in size.

  The connecting portion 24 between the worm shaft 25 and the rotary shaft 3, that is, the other end of the rotary shaft 3 is rotatably supported by a rolling bearing 32 provided in the housing body 42. For this reason, sliding resistance can be reduced compared with a sliding bearing, and it becomes possible to rotate the rotating shaft 3 efficiently. For this reason, the highly efficient electric motor 2 can be provided.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIG. The same aspects as those in the first embodiment will be described with the same reference numerals (the same applies to the following embodiments).
FIG. 5 is a longitudinal sectional view of the electric motor 202 in the second embodiment, and corresponds to FIG.
In the second embodiment, the electric motor 202 includes a bottomed cylindrical yoke 5 having four permanent magnets 7 and an armature 6 rotatably provided in the yoke 5. The bottom wall 51 is formed with a bearing housing 19 that protrudes inward in the axial direction at the radial center, and the brush 21 has a low-speed brush 21a and a high-speed brush 21b connected to the anode side. The basic configuration is the same as that of the first embodiment described above, and the common brush 21c is commonly used for the low-speed brush 21a and the high-speed brush 21b and connected to the cathode side. Yes (the same applies to the following embodiments).

Here, the difference between the second embodiment and the first embodiment described above is that the bearing housing 19 of the first embodiment is slipped in order to rotatably support one end of the rotating shaft 3 of the armature 6. Whereas the bearing 18 is press-fitted and fixed, a rolling bearing 218 is press-fitted and fixed to the bearing housing 19 of the second embodiment.
With this configuration, in addition to the same effects as those of the first embodiment described above, the sliding resistance to the rotating shaft 3 is further reduced by providing the rolling bearing 218 instead of the sliding bearing 18 of the first embodiment. Can be made. For this reason, it becomes possible to rotate the rotating shaft 3 more efficiently, and the more efficient electric motor 202 can be provided.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG.
FIG. 6 is a longitudinal sectional view of the electric motor 302 in the third embodiment, and corresponds to FIG.
The difference between the third embodiment and the first embodiment described above is that a sliding bearing 18 having a centering function is press-fitted and fixed to the bearing housing 19 of the first embodiment. A sliding bearing 318 having no alignment function is press-fitted and fixed to the bearing housing 319 of the embodiment. For this reason, the outer diameter of the sliding bearing 318 of the third embodiment is smaller than the outer diameter of the sliding bearing 18 of the first embodiment.

Also, the outer diameter of the bearing housing 319 is smaller than that of the first embodiment so as to correspond to the outer diameter of the sliding bearing 318. Therefore, the wall thickness of the substantially ring-shaped wall raised from the bottom wall 351 of the yoke 305 toward the inner side in the axial direction in order to form the bearing housing 319 can be increased. As a result, the bottom wall 51 can be formed with an annular recess 319a in an annular shape in plan view in the axial direction at a position corresponding to the bearing housing 319.
Therefore, according to the above-described third embodiment, the same effects as those of the above-described first embodiment can be obtained. In addition to this, by forming the recess 319a, for example, when the paint is applied to the surface of the yoke 5, the entire surface of the yoke 5 can be easily and reliably degreased to improve the adhesion of the paint. Can do.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described with reference to FIG.
FIG. 7 is a longitudinal sectional view of the electric motor 402 in the fourth embodiment, and corresponds to FIG.
The difference between the fourth embodiment and the first embodiment described above is that the bearing housing 19 of the first embodiment and the bearing housing 419 of the fourth embodiment are different. That is, the bearing housing 419 formed on the bottom wall 451 of the yoke 405 in the fourth embodiment also serves as the outer race 18a of the sliding bearing 18 fixed thereto.
Therefore, according to the fourth embodiment, in addition to the same effects as those of the first embodiment, it is possible to reduce the manufacturing cost and to provide an inexpensive and small electric motor 402.

The present invention is not limited to the above-described embodiment, and includes various modifications made to the above-described embodiment without departing from the spirit of the present invention.
For example, in the above-described embodiment, the case where the electric motors 2, 202, 302, and 402 have four permanent magnets 7 is described. However, the present invention is not limited to this, and two or more permanent magnets 7 are provided. It only has to have.

  In the above-described embodiment, the brush 21 is commonly used for the low-speed brush 21a and the high-speed brush 21b connected to the anode side, and the low-speed brush 21a and the high-speed brush 21b and connected to the cathode side. The case where it is configured by three brushes with the common brush 21c being described has been described. However, it is not restricted to this, The brush 21 should just be comprised with at least 2 brush.

  Further, in the above-described embodiment, the core body 11 of the armature core 8 is formed with six circular holes 11b having a circular cross section penetrating in the axial direction at positions corresponding to the roots of the teeth 12 along the circumferential direction. Explained the case. However, the shape of the holes 11b is not limited to a circular cross section, and the number of holes 11b formed is not limited to six. Furthermore, the formation position of the hole 11b is not limited to the position corresponding to the root of the tooth 12 of the core body 11, and the hole 11b can be formed at an arbitrary position.

  Furthermore, in the above-described embodiment, when the electric motors 2, 202, 302, and 402 are such that the armature 6 including the commutator 10 with which the brush 21 is slidably contacted is supported on the yokes 5, 305, and 405 in a freely rotatable manner. Explained. However, the present invention is not limited to this, and the structure of the present invention can be applied to a so-called brushless motor that does not have the brush 21. That is, you may comprise so that the bearing which rotatably supports the rotating shaft of a rotor may be arrange | positioned inside the coil end of the coil currently wound by the stator.

1 Motor with reducer 2, 202, 302, 402 Electric motor 3 Rotating shaft 5, 305, 405 Yoke (motor case)
8 Armature core 9 Armature coil (coil)
11 Core body 11a Hole 12 Teeth 18, 318 Sliding bearing (bearing)
19, 319, 419 Bearing housing 23 Gear housing (motor case)
32,218 Rolling bearing (bearing)
51,351,451 Bottom wall (bottom)

Claims (4)

A motor case,
A rotary shaft that is rotatably supported at both ends by a bearing provided in the motor case;
An armature core having a plurality of teeth attached to the rotating shaft and extending radially in the radial direction;
A coil is wound around each tooth by the concentrated winding method.
The electric motor according to claim 1, wherein at least one of the bearings is arranged so as to face a radially inner side than a coil end of each coil existing on an axial end face side of the armature core.   The electric motor according to claim 1, wherein at least one of the bearings arranged at both ends of the rotating shaft is a rolling bearing. The motor case has a bottomed cylindrical yoke having a plurality of magnetic poles,
A bearing housing that protrudes inward is formed at the bottom of the yoke,
The electric motor according to claim 1, wherein one of the bearings is supported by the bearing housing.   The electric motor according to any one of claims 1 to 3, wherein a hole penetrating in the axial direction is formed radially inward of the teeth of the armature core.

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