JP2010041755A - Commutator motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a commutator motor which secures a dielectric voltage between a laminated core and a stator winding by suppressing movement of a slot insulating member to a commutator side while increasing a space factor with respect to a slot of a rotor. <P>SOLUTION: In the commutator motor, a commutator, the laminated core 17 and insulating end plates 18, 19 which are arranged at both ends of the core are supported to a rotor shaft 16, the slot insulating member 21 is arranged for covering the slot 17c of the laminated core 17 and internal faces of grooves 18c, 19c of the insulating end plates, and the rotor 15 is provided which is wound around the laminated core 17 by inserting a rotor winding 22 connected to the commutator through the insulating member 21 and the inside of the grooves 18c, 19c. A clearance groove (clearance part) 21a is formed at the commutator side end of the insulating member 21. The commutator motor is characterized in that, by this clearance groove, the winding start end 22a of the rotor winding 22 wound across the bottom 21g of the insulating member 21 from the commutator is supported to the insulating end plate 18 at the commutator side in a position at the rotating shaft 16 side lower than the internal face of the bottom 21g. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a commutator motor having an improved slot insulating member of a rotor.

  Conventionally, a slot insulating member having a substantially U-shaped cross section has been used in order to ensure electrical insulation between the laminated core of the rotor and the rotor winding wound around it. When the winding of the rotor wound around the laminated core begins to be wound, the laminated iron core indicates that the slot insulating member moves in the winding direction of the stator winding due to the tension of the stator winding acting on the slot insulating member. There is known a technique for obstructing by insulating end plates disposed at both ends (see, for example, Patent Document 1).

In this technique, a groove-shaped opening provided in an insulating end plate continuous with a slot of the laminated core is formed narrower than the slot so that an end face in the longitudinal direction of the slot insulating member hits an edge of the groove-shaped opening. is doing. With the stopper action, the slot insulating member disposed in the slot is prevented from moving in the winding direction of the stator winding, and the slot insulating member is held in a predetermined position, so that the laminated iron core and the rotor Electrical insulation from the winding can be ensured.
Japanese Patent Laid-Open No. 10-243594

  In the technique of Patent Document 1, since the region corresponding to the bottom of the slot in the opening of the insulating end plate serves as a stopper for at least the slot insulating member, the edge of the bottom in the opening of the insulating end plate that functions as this stopper Thus, when starting to wind the stator winding, it becomes an obstacle to press the bent bottom of the slot insulating member against the bottom of the slot by the tension of the winding. As a result, the stator winding is wound a predetermined number of times with a gap at the bottom of the slot, which is not suitable for increasing the space factor (the stator winding occupation ratio relative to the slot volume).

  In order to increase the space factor, not only the opening of the insulating end plate and the slot have the same shape and the same size, but the slot insulating member not only covers the inner surface of the slot, but also at the longitudinal end portion of the slot insulating member. It is desirable to cover the inner surface of the bottom of the opening of the insulating end plate. Then, in such a configuration, when starting winding the stator winding, when winding the stator winding is started with the bent bottom portion of the slot insulating member pressed against the bottom portion of the slot by the tension of the winding. The inventors have found that the slot insulating member can be prevented from moving in the winding direction of the stator winding by the pressing of the slot against the bottom of the slot.

  However, the present inventors have found the following problems to be improved. In other words, in order to press the bent bottom portion of the slot insulating member against the bottom portion of the slot with the tension of the stator winding, the stator winding having one end connected to the commutator inside the slot insulating member covering the inner surface of the slot. Implemented by inserting a shaping plate through the wire so that it is close to the rotor shaft through which the laminated iron core and insulating end plate are inserted, between the commutator and the insulating end plate on the side close to the commutator. Has been. Thereby, as the commutator side winding end portion (winding start end portion) extending between the commutator and the laminated core is pushed to the rotor shaft side by the shaping plate, the bent bottom portion of the slot insulating member is It can be pressed against the inner surface of the bottom of the slot. The stator winding is wound around the laminated core a predetermined number of times while maintaining this state.

  Therefore, with the insertion of the shaping plate, the slot insulating member may be pulled out to the commutator side by the commutator side winding end and protrude from the opening of the commutator side insulating end plate, The stator winding is wound on the top. When the slot insulating member is pulled out to the commutator side in this way, the end of the insulating member far from the commutator is detached from the insulating end plate that is also far from the commutator. And the stator windings face each other. Therefore, the withstand voltage between them may be lowered.

  The object of the present invention is to increase the space factor of the stator winding with respect to the rotor slot and suppress the movement of the slot insulating member to the commutator side to insulate between the laminated core and the stator winding. An object of the present invention is to provide a commutator motor that can ensure a withstand voltage.

  The present invention supports a commutator, a laminated iron core, and insulating end plates arranged at both ends of the iron core on a rotor shaft, and each slot of the laminated iron core and a groove of an insulating end plate continuous thereto. In a commutator motor including a rotor in which a slot insulating member is disposed so as to cover each inner surface, and a rotor winding connected to the commutator is wound around the laminated iron core through the slot insulating member and the groove, A relief portion is provided at the commutator side end of the slot insulating member, and the winding start end of the rotor winding extending from the commutator to the bottom of the slot insulating member is lower on the rotor shaft side than the inner surface of the bottom of the slot insulating member It is characterized by being supported by an insulating end plate on the commutator side at the position.

  According to the commutator motor of the present invention, while increasing the space factor of the stator winding with respect to the rotor slot, the movement of the slot insulating member to the commutator side is suppressed, and the laminated core and the stator winding Insulation breakdown voltage can be secured.

  The first embodiment of the present invention will be described below with reference to FIGS.

  Reference numeral 1 in FIG. 1 denotes an electric blower that is built in a vacuum cleaner main body of a vacuum cleaner (not shown) and performs a dust blowing operation. The electric blower 1 includes an electric motor frame 2, a stator 11, a rotor 15, a pair of brush devices 8, a fan 31, a diffuser 34, a fan cover 38, and the like. The motor frame 2, the stator 11, the rotor 15, and the pair of brush devices 8 form a motor part M that forms a commutator motor.

  The metal motor frame 2 is formed by connecting a frame body 3 and a frame end face plate 4 having a vent hole. The frame main body 3 is formed in a bottomed cylindrical shape, and the opening edge 3a is bent outwardly and has an annular shape. The frame end face plate 4 crosses the opening of the frame body 3, and both ends thereof are screwed to the opening edge 3a. A bearing 5 is accommodated in a bearing support portion 4 a formed at the center in the longitudinal direction of the frame end face plate 4. The end wall 3b of the frame body 3 is located on the side opposite to the opening of the frame body 3, and a bearing support portion 3c is formed at the center of the end wall 3b, and the bearing 6 is accommodated in the bearing support portion 3c. ing.

  The stator 11 has a stator core having a substantially square outer shape in plan view, and a stator winding wound around the stator core. The stator 11 is fixed in the motor frame 2 with its four corners being in pressure contact with the inner surface of the cylindrical peripheral wall of the frame body 3. An in-frame air passage 12 (only one is shown in FIG. 1) is formed between the outer surface of the stator core and the inner surface of the cylindrical peripheral wall facing the stator core. A plurality of exhaust holes 13 (only one is shown in FIG. 1) are formed in the cylindrical peripheral wall located downstream of the in-frame air passage 12, that is, between the stator 11 and the end wall 3b. .

  As shown in FIGS. 1 to 3, the rotor 15 includes a rotor shaft 16, a laminated core 17 that forms an armature core, a pair of insulating end plates 18 and 19, a commutator 20, and a plurality of slot insulating members 21. And a plurality of rotor windings 22 forming armature windings.

  The laminated iron core 17 is formed in a substantially cylindrical shape by laminating a predetermined number of iron core plates having the same shape and size. The laminated iron core 17 has magnetic pole teeth 17a at regular intervals along the circumferential direction. Protrusions 17b that integrally project on both sides of the teeth are provided at the tips of the plurality of magnetic pole teeth 17a, whereby each magnetic pole tooth 17a is substantially T-shaped as shown in FIG. I am doing.

  The laminated iron core 17 has a plurality of slots 17c that are open to the circumferential surface and both ends in the lamination direction and have a substantially U shape when the rotor 15 is viewed in the axial direction. These slots 17 c are formed between the magnetic pole teeth 17 a adjacent in the circumferential direction of the laminated core 17. The open end opened to the peripheral surface of the laminated iron core 17 of each slot 17c is narrowed by the protrusions 17b of the magnetic pole teeth 17a. The magnetic pole teeth 17 a and the slots 17 c are provided radially with respect to the center of the laminated iron core 17.

  The insulating end plates 18 and 19 are made of an insulating material such as hard synthetic resin, and are continuously disposed at both ends of the laminated iron core 17. As shown in FIG. 3, these insulating end plates 18 and 19 are formed of laminated plate portions 18a and 19a, and cylindrical shaft portions 18b and 19b that project integrally with the middle layer portions thereof.

  The laminated plate portions 18a and 19a are portions disposed on the end surface of the laminated iron core 17, and the thickness B thereof is, for example, 1.5 mm to 2.0 mm. These laminated plate portions 18a and 19a have a plurality of grooves 18c and 19c (see FIGS. 4 and 6) that are continuous with the respective slots 17c on the peripheral portions thereof. The grooves 18c and 19c are substantially U-shaped, and the depth thereof is the same as the depth of each slot 17c, so that the bent bottom surface of the grooves 18c and 19c and the bent bottom surface of each slot 17c are rotated. There is no difference in the height position with respect to the radial direction (radial direction) of the rotor 15, and it is continuous with the axial direction of the rotor 15. Therefore, the laminated plate portions 18a and 19a have substantially the same shape as the iron core plate. In the present embodiment, as shown in FIGS. 4 and 6A and 6B, the plurality of tooth overlap portions 18d and 19d that form the grooves 18c and 19c between each other are portions that overlap the protrusion 17b. Although it does not have, you may have the site | part which overlaps with the said protrusion 17b.

  The rotor shaft 16 is press-fitted into the central portion of the laminated iron core 17 and the shaft portions 18b and 19b of the insulating end plates 18 and 19 disposed continuously at both ends of the laminated iron core 17, and is provided therethrough. The laminated core 17 and the insulating end plates 18 and 19 are supported.

  The commutator 20 is fixed to one end of the rotor shaft 16. The commutator 20 has the same number of commutator pieces 20a as the slots 17c.

  Each slot insulating member 21 is made of an electrically insulating material such as polyester resin. As shown in FIGS. 5A and 5B, these slot insulating members 21 are bent into a substantially V shape or a substantially U shape, and both end portions in the direction in which the bottom portion composed of the bent portion extends are provided. In addition, there is a relief portion composed of a relief groove 21a opened at these ends. The escape groove 21a is formed at the same time as the slot insulating member 21 is formed, or is formed by cutting out a corresponding portion after the forming, and the shape thereof is substantially V-shaped or substantially U-shaped.

  As shown in FIGS. 6A and 6B, these slot insulating members 21 cover the inner surfaces of the slots 17c and the grooves 18c and 19c continuously provided at both ends thereof, and are disposed inside the slots 17c. . In the present embodiment, the total length L of the slot insulating member 21 is the sum of the length A of the laminated iron core 17 shown in FIG. 6A and the thickness B of the laminated plate portions 18a and 19a of the insulating end plates 18 and 19. Although it is the same as the size, it may be slightly longer than this total size. The depth D of the escape groove 21a shown in FIGS. 5B and 6A is shorter than the thickness B of the laminated plate portions 18a and 19a of the insulating end plates 18 and 19. The difference E between BD shown in FIG. 6 (A) is preferably 0.8 mm or more. Therefore, as shown in FIGS. 4 and 6A and 6B, the escape portion 21a is positioned within the width of the laminated plate portions 18a and 19a, and a part of the bottom surfaces of the grooves 18c and 19c. The bottom surface portion away from the laminated iron core 17 is exposed.

  Each rotor winding 22 is connected to the commutator piece 20a of the commutator 20 at both ends, and the laminated iron core 17 passes through the inside of the slot insulating member 21 and the grooves 18c and 19c at corresponding positions between the both ends. And it is wound around the laminated board parts 18a and 19a.

  As described above, the rotor 15 is provided with the laminated iron core 17 in which the rotor winding 22 is insulated and the commutator 20 to which the winding terminal of the rotor winding 22 is connected. 1, the rotor shaft 16 is rotatably supported by the bearings 5 and 6, and is attached to the motor frame 2 through the inside of the stator 11 as shown in FIG. With this attachment, the commutator 20 is disposed between the laminated iron core 17 and the bearing 6. At the same time, the rotor shaft 16 penetrates the bearing 5 and the bearing support portion 4a and protrudes outside the motor frame 2.

  As shown in FIG. 1, the pair of brush devices 8 are attached to the frame body 3 by being electrically insulated, and are provided so as to penetrate the frame body 3 in the radial direction. The carbon brushes 8a included in these brush devices 8 are pressed against the commutator 20 by coil springs 8b.

  The fan 31, the diffuser 34, and the fan cover 38 form a fan part F.

  Specifically, as shown in FIG. 1, the fan 31 is fixed to a shaft end portion of the rotor shaft 16 projecting out of the motor frame 2 by a nut screwed thereto. The fan 31 is of a centrifugal type having an intake port 31a at the center of the front shroud and a discharge port 31b on the peripheral surface. The diffuser 34 that statically reduces the airflow discharged from the discharge port 31b and guides it to the in-frame air passage 12 of the electric motor frame 2 is disposed between the fan 31 and the electric motor frame 2, and includes the frame end face plate 4 and the frame. It is screwed to the opening edge 3 a of the main body 3. The fan cover 38 is attached by fitting its peripheral portion to the opening edge 3 a of the electric motor frame 2, and covers the peripheral portion of the diffuser 34 and the fan 31. The fan cover 38 has a suction port 38a opposite to the suction port 31a at the center thereof.

  The electric blower 1 having the above configuration can rotate the fan 31 together with the rotor 15 by energizing the electric motor unit M. As a result, the airflow flows through the suction port 38a, the fan 31, the diffuser 34, the in-frame air passage 12, and the exhaust hole 13 in this order, and the air blowing operation for dust suction of the vacuum cleaner is performed.

  In the assembly of the electric motor part M of the electric blower 1, the rotor winding 22 is wound using an automatic winding machine, and the winding machine includes a shaping plate 41 shown in FIG. And a flyer (not shown) for gripping and routing the rotor winding 22.

  In the winding machine, the flyer holding the rotor winding 22 is connected in a state where the winding start end (commutator side winding end) 22a of the rotor winding 22 is connected to the commutator piece 20a of the commutator 20. By moving, the rotor winding 22 is routed a predetermined number of times across the slot 17c that is spaced 180 ° in the circumferential direction of the laminated core 17 and that corresponds to the radial direction. In FIG. 6 (B), the fryer is rotated counterclockwise to perform the winding work. As a result, the wire is wound through the slot 17c of the laminated iron core 17 and the inside of the slot insulating member 21 already provided over the grooves 18c and 19c of the laminated plate portions 18a and 19a continuous at both ends thereof. The rotor winding 22 is insulated from the laminated iron core 17 by the slot insulation member 21. Further, the winding end end portion of the rotor winding 22 is connected to a commutator piece 20a that is spaced 180 ° in the circumferential direction of the commutator 20 with respect to the commutator piece 20a to which the winding start end portion 22a is connected. .

  When starting to wind the rotor winding 22, the winding machine passes through the rotor winding 22 having one end connected to the commutator 20 in the slot 17 c where the slot insulating member 21 is arranged as described above. The shaping plate 41 is moved from the position indicated by the two-dot chain line in FIGS. 3 and 6B to the position indicated by the solid line between the commutator 20 and the insulating end plate 18 on the side close thereto. Let That is, the shaping plate 41 is inserted so as to approach the rotor shaft 16.

  As the winding start end portion 22a is pushed to the rotor shaft 16 side by the shaping plate 41, the rotor winding 22 to which tension is applied presses the bottom portion 21g of the slot insulating member 21 against the bottom portion of the slot 17c. It becomes.

  In this case, the commutator side end portion of the winding start end portion 22a of the rotor winding 22, that is, the end portion extending from the commutator 20 to the bottom portion 21g of the slot insulating member 21 is pressed by the shaping plate 41 as described above. 6B, the groove 18c passes through the relief groove 21a of the slot insulation member 21 and the edge 21d of the rear end of the relief groove 21a and the insulation end plate 18 on the commutator 20 side as shown in FIG. Is in contact with the corner 18e on the commutator 20 side at the bottom of the rotor and is pushed toward the rotor shaft 16 side. The edge 21d is positioned higher than the bottom surface of the groove 19c of the insulating end plate 19 in the radial direction of the rotor 15. That is, the winding start end portion 22 a pushed by the shaping plate 41 is supported by the insulating end plate 18 on the commutator 20 side at a position lower than the inner surface of the bottom portion 21 g of the slot insulating member 21 on the rotor shaft 16 side.

  Thus, when the shaping plate 41 pushes the winding start end portion 22a toward the rotor shaft 16, the winding start end portion 22a is supported by the insulating end plate 18 through the relief groove 21a of the slot insulating member 21. The action of the winding start end 22a dragging the slot insulating member 21 toward the commutator 20 with the insertion of the plate 41 can be reduced or eliminated. Therefore, along with the insertion of the shaping plate 41 for pressing the bottom of the slot insulating member 21 against the bottom 21g of the slot 17c at the winding start end 22a of the rotor winding 22, the slot insulating member 21 is pulled out to the commutator 20 side. Thus, the protrusion from the insulating end plate 18 is prevented.

  Since the slot insulating member 21 is thus held at a predetermined position, the end of the slot insulating member 21 far from the commutator 20 does not come off from the insulating end plate 18 that is also far from the commutator 20. Therefore, since the slot insulating member 21 is reliably interposed between the laminated core 17 and the rotor winding 22 also on the insulating end plate 18 side, the withstand voltage between them is not lowered.

  Then, with the shaping plate 41 being placed at the position indicated by the solid line in FIG. 6B, the winding machine moves the filler to perform the winding operation described above. In this winding, as described above, the bottom portion 21g of the slot insulating member 21 is pressed against the bottom surface of the slot 17c, and the rotor winding 22 is wound in a state where there is no gap between them, The winding space factor (occupation ratio of the rotor winding 22 with respect to the volume of the slot 17c) can be increased.

  As described above, according to the motor unit M configured as described above, the space factor of the rotor winding 22 with respect to the slot 17c of the rotor 15 is increased, and the movement of the slot insulating member 21 toward the commutator 20 is suppressed. The dielectric strength between the laminated iron core 17 and the rotor winding 22 can be ensured.

  A second embodiment of the present invention will be described with reference to FIGS. Since 2nd Embodiment is the same as 1st Embodiment except the matter demonstrated below, the same code | symbol as the applicable structure of 1st Embodiment is attached | subjected to the same structure as 1st Embodiment, and the description is abbreviate | omitted. The second embodiment differs from the first embodiment in the configuration of the slot insulating member and its relief portion.

  That is, in the second embodiment, the slot insulating member 21 includes a soft and thin first insulating sheet 21b that can be freely deformed, and a second insulating sheet 21c made of polyester resin that is thicker and easier to elastically deform. It is formed by stacking. The length of the first insulating sheet 21b defines the total length of the slot insulating member 21, and this total length L is equal to the length A of the laminated iron core 17 and the laminated plate portions 18a and 19a of the insulating end plates 18 and 19. It is the same as the total dimension of the thickness B or slightly longer. The second insulating sheet 21 c is shorter than the length of the first insulating sheet 21 b, but longer than the length A of the laminated core 17.

  With this configuration, both end portions of the first insulating sheet 21b protrude from both end portions of the second insulating sheet 21c, and the protruding portion is a thin portion 21be that forms a freely deformable escape portion. , 21bf. The thin portions 21be, 21bf have a width shorter than the thickness of the insulating end plates 18, 19. The bottom of the thin-walled portion 21be on the commutator side covers the bottom surface of the groove 18c of the insulating end plate 18 on the commutator side, and a step is formed between the bottom 21g of the second insulating sheet 21c and one end in the longitudinal direction. Forming. Similarly, the bottom portion of the fan-side thin portion 21bf covers the bottom surface of the groove 19c of the fan-side insulating end plate 19, and is between the bottom portion 21g of the second insulating sheet 21c and the other end portion in the longitudinal direction. A step is formed.

  Configurations other than those described above are the same as those in the first embodiment, including configurations not shown in FIGS. 7A and 7B.

  In the winding when the rotor is manufactured in the second embodiment, the winding start end portion 22a of the rotor winding 22 pressed by the shaping plate 41 is the slot insulating member 21 as described in the first embodiment. Is supported by the insulating end plate 18 on the commutator 20 (see FIGS. 1 to 3) side at a position lower than the inner surface of the bottom portion 21g on the rotor shaft 16 (see FIGS. 1 to 3) side. In this case, the winding start end portion 22a is indirectly supported by the commutator side corner 18e at the bottom of the groove 18c of the insulating end plate 18 through the thin portion 21be.

  Thus, when the shaping plate 41 pushes the winding start end portion 22a toward the rotor shaft 16, the winding start end portion 22a is supported by the insulating end plate 18 via the thin portion 21be of the slot insulating member 21, so that shaping is performed. The action of the winding start end portion 22a dragging the slot insulating member 21 toward the commutator side with the insertion of the plate 41 can be reduced or eliminated. In this case, the winding start end portion 22a does not have any effect of dragging the slot insulating member 21 to the commutator side via the thin portion 21be, but the thin portion 21be can be deformed freely. The fact that the insulating member 21 is dragged to the commutator side can be substantially ignored.

  Therefore, along with the insertion of the shaping plate 41 for pressing the bottom portion 21g of the slot insulating member 21 to the bottom portion of the slot 17c at the winding start end portion 22a of the rotor winding 22, the slot insulating member 21 is pulled out to the commutator 20 side. Thus, it is prevented from projecting from the insulating end plate 18 and winding can be performed while the slot insulating member 21 is held in a predetermined position.

  Therefore, the object of the present invention can also be achieved in the second embodiment. That is, while increasing the space factor of the rotor winding 22 with respect to the slot 17 c of the rotor 15, the movement of the slot insulating member 21 toward the commutator side is suppressed, so that the gap between the laminated core 17 and the rotor winding 22 is reduced. It is possible to ensure a high withstand voltage.

  In addition, this invention is not restrict | limited to implementation as an electric motor part of an electric blower positive, It can implement as a commutator electric motor single-piece | unit.

The side view which cuts and shows the electric blower provided with the commutator motor which concerns on 1st Embodiment of this invention as an electric motor part. The perspective view which decomposes | disassembles and shows the rotor which the commutator motor of FIG. Sectional drawing which shows the rotor with which the commutator motor of FIG. 1 is provided. The perspective view which expands and shows a part of rotor of FIG. 3 in the state before winding. (A) is a perspective view which shows the slot insulation member with which the rotor of FIG. 3 is provided. (B) is a front view showing the slot insulating member. (A) is sectional drawing which expands and shows a part of rotor of FIG. 3 in the state before a rotor coil | winding is wound. (B) is sectional drawing which expands the said part and shows a shaping board in the state by which a rotor coil | winding begins to wind. (A) is sectional drawing which shows a part of rotor with which the commutator motor which concerns on 2nd Embodiment of this invention is provided in a state before a rotor coil | winding is wound. (B) is sectional drawing which shows the same part with a shaping board in the state by which a rotor coil | winding begins to wind.

Explanation of symbols

  M: Motor part (commutator motor), 2 ... Electric motor frame, 11 ... Stator, 15 ... Rotor, 16 ... Rotor shaft, 17 ... Laminated core, 17a ... Magnetic pole teeth, 17c ... Slot, 18 ... Insulated end plate 19 ... Insulating end plate on the commutator side, B ... Thickness of the insulating end plate, 18c, 19c ... Groove, 19e ... Edge, 20 ... Commutator, 21 ... Slot insulating member, 21a ... Relief groove of slot insulating member (escape) Part), 21g ... bottom of the slot insulation member, 21be ... thin wall part (relief part), D ... depth of escape groove, 22 ... rotor winding, 22a ... winding start end part

Claims (3)

Comprising a stator and a rotor disposed inside the stator;
The rotor is disposed at both ends of the laminated core having a plurality of slots and a plurality of magnetic pole teeth formed between the slots, and a plurality of grooves continuous to the slots. An insulating end plate, a plurality of slot insulating members disposed so as to cover the inner surfaces of the slot and the groove that are continuous with each other, and a rotor shaft that inserts and supports the laminated core and the insulating end plate A commutator comprising a commutator fixed to one end of the rotor shaft, and a rotor winding connected to the commutator and wound around the laminated core through the inside of the slot insulating member. In the electric motor,
The winding start end portion of the rotor winding extending from the commutator to the bottom portion of the slot insulating member at the commutator side end portion of the slot insulating member is positioned lower than the inner surface of the bottom portion on the rotor shaft side. A commutator motor provided with a relief portion to be supported on the insulating end plate on the commutator side.   The relief portion is formed by a relief groove provided at the bottom of the slot insulation member and at the commutator side end of the slot insulation member and opening to the end of the slot insulation member on the commutator side. The commutator motor according to claim 1, wherein a depth of the groove is shorter than a thickness of the insulating end plate on the commutator side.   The relief portion is formed by a thin portion provided at a bottom portion of the slot insulating member and at the commutator side end portion of the slot insulating member and covering a bottom surface of a groove of the insulating end plate on the commutator side. The commutator motor according to claim 1, wherein the portion is freely deformable.

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