Brush holder for brushed motor and brushed motor

Abstract

To provide a brush base for a brush motor which corresponds to multiple kinds of lead wires with different thicknesses.SOLUTION: An insertion hole 35 penetrated from an outside face 31a to an inside face 31b is formed through which a lead wire 39 (38) can be inserted from the outside face 31a side. The insertion hole 35 is formed having some thicknesses corresponding to the different thicknesses of multiple kinds of lead wires 39, which are predetermined for each of the lead wires 39 to be inserted. As an example, the insertion hole 35 includes a large diameter part 33 and a small diameter part 34, which have different diameters corresponding to the different thicknesses of two kinds of lead wires 39, and which are arranged in an axis C2 direction of the insertion hole 35 so that each thickness of the lead wires 39 inserted from the insertion side in the insertion direction is in order from large to small.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a brush base for a brushed motor and a brushed motor. [Background technology]

[0002] A brush motor includes brushes that are arranged on a brush base and connected to lead wires that are inserted into holes formed in the brush base (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-069730 Summary of the Invention [Problem to be solved by the invention]

[0004] The holes in the brush base are formed to correspond to the diameter of the lead wires so that the lead wires can be lightly pressed in. By lightly pressing the lead wires into the holes in this way, frictional force is generated between the outer surface of the lead wires and the inner surface of the holes, and the lead wires are held in place by the brush base while inserted in the holes.

[0005] In this way, by holding the lead wire on the brush base, when joining the core wire of the lead wire to the brush held on the brush base with solder or the like, it is not necessary to hold the lead wire with fingers to prevent it from falling off the brush base, thereby improving workability.

[0006] However, if a brush holder is used for multiple motors with different specifications, the brush holder must be compatible with lead wires of different thicknesses. For example, motors with different outputs require different current values, so lead wires of different thicknesses must be used according to the current values.

[0007] SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a brush base for a brush motor and a brush motor that can accommodate a plurality of types of lead wires with different thicknesses. [Means for solving the problem]

[0008] The first aspect of the present invention is a brush base for a brushed motor, which has an insertion hole that penetrates from the outer surface to the inner surface and into which a lead wire is inserted from the outer surface side, and the insertion hole is formed with a thickness that corresponds to the thickness of multiple types of lead wires that have different thicknesses that are preset as the lead wire to be inserted.

[0009] The second aspect of the present invention is a brush motor comprising a stator assembly, a rotor assembly, and a brush base assembly, wherein the brush base assembly has the brush base described in claim 1, brushes fixed to the inner surface side of the brush base, and lead wires inserted from the outer surface side into insertion holes that penetrate from the outer surface to the inner surface of the brush base and connected to the brushes on the inner surface side. [Effects of the Invention]

[0010] The brush base for a brushed motor and the brushed motor according to the present invention can accommodate a variety of lead wires with different thicknesses. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a partial cross-sectional view showing a brushed motor. [Figure 2] 2 is a perspective view showing a state in which lead wires are inserted into a brush base of the brush motor shown in FIG. 1. FIG. [Figure 3] 2 is a cross-sectional view showing a brush base of the brush motor shown in FIG. 1. [Figure 4] 10 is a cross-sectional view of a main part showing a state before a lead wire having a relatively small outer diameter, which has been preset as the lead wire to be inserted, is inserted into an insertion hole of the brush base. FIG. [Figure 5]5 is a cross-sectional view of a main part showing a state in which a lead wire has been inserted into an insertion hole, following the state shown in FIG. 4. FIG. [Figure 6] 10 is a cross-sectional view of a main part showing a state before a lead wire having a relatively large outer diameter, which has been preset as the lead wire to be inserted, is inserted into an insertion hole of the brush base. FIG. [Figure 7] 7 is a cross-sectional view of a main part showing a state in which a lead wire has been inserted into an insertion hole, following the state shown in FIG. 6. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a brush holder for a brush motor and a brush motor according to the present invention will be described below with reference to the drawings.

[0013] <Configuration> FIG. 1 is a partial cross-sectional view showing a brush motor 100, FIG. 2 is a perspective view showing the state in which lead wires 38 and 39 are inserted into the brush base of the brush motor 100 shown in FIG. 1, and FIG. 3 is a cross-sectional view showing the brush base of the brush motor 100 shown in FIG. 1.

[0014] Brush motor 100 (hereinafter simply referred to as motor 100) is one embodiment of a brush motor according to the present invention, and brush base 31 is one embodiment of a brush base for a brush motor according to the present invention.

[0015] The motor 100 includes a stator assembly 10, a rotor assembly 20, and a brush base assembly 30. The rotor assembly 20 is disposed inside the stator assembly 10, and the brush base assembly 30 closes an opening at one end of the stator assembly 10 (the right side in FIG. 1).

[0016] The rotor assembly 20 includes a rotating shaft 21, a cup coil 22, a mold 23, and a commutator 24. The rotating shaft 21 is formed in a linearly extending columnar shape. The cup coil 22 is formed in a cylindrical shape. The cup coil 22 is disposed radially outward of the rotating shaft 21.

[0017] Mold 23 is connected to rotating shaft 21 on the central side and to cup coil 22 on the outer periphery. As a result, cup coil 22, mold 23, and rotating shaft 21 are integrated with an arrangement in which the cylindrical axis of cup coil 22 coincides with axis C1 of rotating shaft 21. Commutator 24 is arranged to extend from the outer periphery of mold 23, which is arranged on one end side of rotating shaft 21, to the vicinity of cup coil 22, and is electrically connected to an electric wire drawn out from cup coil 22.

[0018] The stator assembly 10 includes a housing 11, a magnet support member 12, a magnet 13, plain bearings 14 and 15, and thrust bearings 16 and 17.

[0019] Housing 11 also serves as the exterior (case) of motor 100, accommodating rotor assembly 20 therein, and is formed in a cylindrical shape with an outer diameter larger than that of cup coil 22 and an end plate 11a at one end. Magnet support member 12 is formed in a substantially cylindrical shape. Rotating shaft 21 is disposed on the inner peripheral surface of magnet support member 12 with a predetermined gap between them. Plain bearings 14 and 15 are fixed to both ends of magnet support member 12 in the direction of axis C1, and the plain bearings 14 and 15 rotatably support rotating shaft 21.

[0020] An end plate 11a of the housing 11 is fixed to the other end of the magnet support member 12 in the axial direction C1 (the left end in Figure 1), and one end of the rotating shaft 21 protrudes outside the housing 11 and serves as the output shaft of the motor 100.

[0021] A cylindrical magnet 13 is fixed to the outer peripheral surface of the magnet support member 12. This integrates the housing 11, magnet support member 12, and magnet 13. The magnet 13 is positioned so as not to come into contact with the cup coil 22 and mold 23 of the rotor assembly 20.

[0022] A thrust bearing 17 is provided between the mold 23 of the rotating rotor assembly 20 and the sliding bearing 15 of the non-rotating stator assembly 10, and this thrust bearing 17 receives pressure acting on the other end side of the rotor assembly 20 in the direction of axis C1 (the left side in Figure 1).

[0023] In addition, a thrust bearing 16 is provided between a bush 25 fixed to the rotating shaft of the rotating rotor assembly 20 and a sliding bearing 14 of the non-rotating stator assembly 10, and this thrust bearing 16 receives pressure acting on one end side of the rotor assembly 20 in the direction of axis C1 (the right side in Figure 1).

[0024] The brush base assembly 30 includes a brush base 31, two brushes 32, 32, and two lead wires 38, 39. The brush base 31 is formed in a substantially circular plate shape. The brush base 31 is disposed so as to close the open end face of the housing 11 in the axial C1 direction (the end face on the right side in FIG. 1).

[0025] The two brushes 32, 32 are fixed to the inner surface 31b of the brush base 31, and as shown in Figure 2, each includes a leaf spring 32a and a brush body 32b. The leaf spring 32a is made of a conductive metal, and the brush body 32b is made of conductive, wear-resistant carbon or the like. One end of the leaf spring 32a is fixed to the brush base 31, and the other end is not fixed. Therefore, the other end of the leaf spring 32a is elastically deformable relative to the one end.

[0026] The brush body 32b is joined to the other free end of the leaf spring 32a and is electrically conductive. As shown in Fig. 1, the brush body 32b is disposed so as to contact the commutator 24 from the outside in the radial direction of the axis C1. At this time, the brush body 32b is pressed against the commutator 24 by the deflection of the leaf spring 32a.

[0027] 3, the brush base 31 has an insertion hole 35 formed along the axis C1 direction from an outer surface 31a exposed to the outside of the motor 100 to an inner surface 31b on the inside side of the motor 100. The inner surface 31b of the brush base 31 has a recess 36 that surrounds the opening where the insertion hole 35 faces and is recessed toward the outer surface 31a. The insertion hole 35 opens to a bottom surface 36a of the recess 36.

[0028] The insertion holes 35 are holes through which the lead wires 38 and 39 are inserted from the outer surface 31a to the inner surface 31b. Note that the cross-sectional view shown in Fig. 3 is drawn as if the insertion hole 35 is formed only on the lower side of the shaft C1 because the cut surfaces are different between the upper and lower sides of the shaft C1. However, as shown in Fig. 2, the brush base 31 has two insertion holes 35, 35 formed therein corresponding to the lead wires 38 and 39, respectively.

[0029] 2, each insertion hole 35 is formed near a fixed portion of the brush base 31 to which one end of the leaf spring 32a is fixed. As a result, the core wires 38a, 39a of the lead wires 38, 39 inserted from the outer surface 31a into the insertion hole 35 are arranged adjacent to one end of the leaf spring 32a of the brush 32 fixed to the inner surface 31b of the brush base 31, and the adjacent core wires 38a, 39a and one end of the leaf spring 32a are respectively joined by soldering or the like. The core wires 38a, 39a and the leaf spring 32a may also be joined by welding.

[0030] This electrically connects the leads 38, 39, brush 32, commutator 24 and cup coil 22, and when power is supplied to the leads 38, 39, the rotor assembly 20 rotates around axis C1 relative to the stator assembly 10 and brush base assembly 30.

[0031] Here, the detailed configuration of the insertion hole 35 will be described. As shown in FIG. 3, the insertion hole 35 is formed with an axis along an axis C2 parallel to the axis C1. The insertion hole 35 is formed with a large-diameter portion 33 having a relatively large inner diameter and a small-diameter portion 34 having a relatively small inner diameter, arranged side by side in the direction of the axis C2. The large-diameter portion 33 and the small-diameter portion 34 are formed coaxially with the axis C2 as a common axis, and are formed so that the diameters of the portions decrease sequentially from the insertion side in the insertion direction of the lead wires 38 and 39. That is, the insertion hole 35 has the large-diameter portion 33 formed on the side closer to the outer surface 31a, and the small-diameter portion 34 formed on the side closer to the bottom surface 36a of the recess 36.

[0032] The inner diameter of the large diameter portion 33 is set to correspond to the outer diameters of two types of lead wires that are preset as the lead wires 38, 39 used with this brush base 31. In other words, the brush base 31 can be used for multiple types of brush motors with different specifications, and the multiple types of brush motors are divided into two types: those that use lead wires with a large outer diameter and those that use lead wires with a small outer diameter.

[0033] That is, the brush base 31 is designed to selectively insert either the lead wires 38, 39 having a relatively large outer diameter or the lead wires 38, 39 having a relatively small outer diameter as the lead wires 38, 39. The large diameter portion 33 is formed with an inner diameter large enough to lightly press-fit the lead wires 38, 39 having a relatively large outer diameter, and the small diameter portion 34 is formed with an inner diameter large enough to lightly press-fit the lead wires 38, 39 having a relatively small outer diameter.

[0034] The degree to which the lead wires 38, 39 can be lightly pressed in means, for example, that when the lead wires 38, 39 are inserted into the insertion hole 35, the lead wires 38, 39 can be inserted lightly without bending just before the insertion hole 35, and that when the lead wires 38, 39 are inserted into the insertion hole 35, the outer surfaces 38c, 39c of the lead wires 38, 39 come into contact with the inner surface of the insertion hole 35, so that the lead wires 38, 39 do not easily fall out of the insertion hole 35 even when the brush base 31 is tilted so that the outer surface 31a side is lower than the inner surface 31b side.

[0035] The boundary between the large diameter portion 33 and the small diameter portion 34 is formed with a tapered surface 35b where the inner diameter changes continuously and at a constant level from the inner circumferential surface 33a of the large diameter portion 33 to the inner circumferential surface 34a of the small diameter portion 34.

[0036] A tapered surface 35a similar to the tapered surface 35b is formed at the boundary between the large diameter portion 33 and the outer surface 31a of the insertion hole 35. This tapered surface 35a also chamfers the corner of the boundary between the inner circumferential surface 33a of the large diameter portion 33 and the outer surface 31a.

[0037] 2 and 3, a protrusion 37 is formed at the opening of the insertion hole 35 on the bottom surface 36a side of the small diameter portion 34 (the opening on the exit side in the insertion direction) to block part of the opening of the small diameter portion 34. The protrusion 37 is formed with a dimension smaller than the depth of the recess 36 from the bottom surface 36a of the recess 36 (the dimension along the axis C2 between the inner surface 31b and the bottom surface 36a). Therefore, the protrusion 37 does not reach the inner surface 31b.

[0038] <effect> The following describes the operation of the brush base 31 of this embodiment configured as described above and the motor 100 equipped with this brush base 31. Fig. 4 is a cross-sectional view of the essential part showing the state before lead wire 39 (the same applies to lead wire 38) with a relatively thin outer diameter, which is preset as the lead wire to be inserted, is inserted into insertion hole 35 of brush base 31, and Fig. 5 is a cross-sectional view of the essential part showing the state after lead wire 39 has been inserted into insertion hole 35 from the state shown in Fig. 4.

[0039] Also, Figure 6 is a cross-sectional view of a key part showing the state before lead wire 39 (the same is true for lead wire 38) with a relatively thick outer diameter, which has been preset as the lead wire to be inserted, is inserted into insertion hole 35 of brush base 31, and Figure 7 is a cross-sectional view of a key part showing the state after lead wire 39 has been inserted into insertion hole 35 from the state shown in Figure 6.

[0040] 4 or 6, the lead wire 39 (the same applies to the lead wire 38) with the exposed core wire 39a is inserted along the axis C2 from the outer surface 31a side into the insertion hole 35 of the brush base 31. At this time, even if the position of the core wire 39a of the lead wire 39 is slightly shifted in a plane perpendicular to the axis C2 from the insertion hole 35, the tip of the core wire 39a will be guided along the axis C2 when it comes into contact with the tapered surface 35a of the insertion hole 35 facing the outer surface 31a.

[0041] Therefore, compared to a brush base that does not have a tapered surface 35a, the brush base 31 of this embodiment can properly guide the lead wire 39 into the insertion hole 35 without the lead wire 39 hitting the outer surface 31a and being bent.

[0042] Furthermore, after the core wire 39a is inserted into the large diameter portion 33 of the insertion hole 35, the exposed core wire 39a of the lead wire 39 advances to the small diameter portion 34. At this time, even if the position of the core wire 39a of the lead wire 39 is slightly shifted from the insertion hole 35 in a plane perpendicular to the axis C2, the tip of the core wire 39a will be guided along the axis C2 when it hits the tapered surface 35b formed at the boundary with the small diameter portion 34.

[0043] Therefore, compared to a brush base that does not have a tapered surface 35b, the brush base 31 of this embodiment can properly guide the lead wire 39 to the small diameter portion 34 without the lead wire 39 hitting the step surface (which does not exist in the brush base 31 of this embodiment) that forms the boundary with the small diameter portion 34 and causing the lead wire 39 to bend.

[0044] After the core wire 39a is inserted into the small diameter portion 34 of the insertion hole 35, the exposed core wire 39a of the lead wire 39 passes through the small diameter portion 34 and protrudes toward the interior of the motor 100. Here, a protrusion 37 that closes a portion of the opening on the bottom surface 36a side of the small diameter portion 34 (the opening on the exit side in the insertion direction) is formed. However, since this protrusion 37 only closes a portion of the opening that is biased to one side from the axis C2, the tip of the core wire 39a does not abut against the protrusion 37. Therefore, the protrusion 37 does not interfere with the operation of inserting the lead wire 39 into the insertion hole 35.

[0045] 5, the coating 39b that covers the core 39a of the lead wire 39 from the outside is lightly press-fitted into the small diameter portion 34. In other words, the coating 39b of the lead wire 39 is inserted into the small diameter portion 34 while the outer circumferential surface 39c of the lead wire 39 (the outer circumferential surface of the coating 39b) is lightly in contact with the inner circumferential surface 34a of the small diameter portion 34.

[0046] Since the outer diameter of the covering portion 39b is larger than the outer diameter of the core wire 39a, the tip surface 39d of the covering portion 39b abuts against the protrusion 37, thereby preventing the insertion of the lead wire 39. In other words, the protrusion 37 determines the position of the lead wire 39 in the insertion direction when the lead wire 39, which has a relatively small outer diameter, is inserted into the insertion hole 35.

[0047] At this time, the core wire 39a is held in close proximity to the brush 32 as shown in FIG. 5, so that the core wire 39a and the brush 32 can be joined by soldering or the like.

[0048] Furthermore, since the lead wires 39 are held in the brush base 31 by light press-fitting, the workability of soldering the core wires 39a and the brushes 32 can be improved.

[0049] Furthermore, when the brush base 31 is held in a horizontal position (with the bottom surface 36a of the recess 36 held horizontal), and a thermosetting adhesive, for example, is poured into the recess 36, allowing the adhesive to seep from the recess 36 into the tiny gap between the inner surface 34a of the small diameter portion 34 and the outer surface 39c of the lead wire 39, and the brush base 31 and the lead wire 39 are joined, the adhesive accumulates in the recess 36, thereby preventing or suppressing the adhesive from spreading to the area outside the recess 36.

[0050] 7, the coating portion 39b of the lead wire 39 is lightly press-fitted into the large diameter portion 33. In other words, the coating portion 39b of the lead wire 39 is inserted into the large diameter portion 33 while the outer circumferential surface 39c of the lead wire 39 (the outer circumferential surface of the coating portion 39b) is lightly in contact with the inner circumferential surface 33a of the large diameter portion 33.

[0051] Since the outer diameter of the covering portion 39b is larger than the inner diameter of the small diameter portion 34, the tip surface 39d of the covering portion 39b abuts against the tapered surface 35b, which is the boundary with the small diameter portion 34, thereby preventing the insertion of the lead wire 39. In other words, the tapered surface 35b determines the position of the lead wire 39 in the insertion direction when the lead wire 39, which has a relatively large outer diameter, is inserted into the insertion hole 35.

[0052] In addition, if a tapered surface 35b is not formed at the boundary between the small diameter portion 34 and the large diameter portion 33 of the brush base 31, a step surface is formed due to the difference in inner diameter between the small diameter portion 34 and the large diameter portion 33, and this step surface serves to position the lead wire 39, which has a relatively thick outer diameter, in the insertion direction when it is inserted into the insertion hole 35.

[0053] When the lead wire 39 is positioned in the insertion direction, the core wire 39a is held in close proximity to the brush 32, as shown in Figure 7, so that the core wire 39a and the brush 32 can be joined by soldering or the like.

[0054] Furthermore, since the lead wire 39 is held in the insertion hole 35 of the brush base 31 by light press-fitting, when the worker performs work such as soldering the core wire 39a to the brush 32, there is no need for the worker to hold the lead wire 39 on the brush base 31 with their fingers or the like while the lead wire 39 is inserted into the insertion hole 35, thereby improving workability.

[0055] Furthermore, when the brush base 31 is held in a horizontal position (with the bottom surface 36a of the recess 36 held horizontal), and a thermosetting adhesive, for example, is poured into the recess 36, allowing the adhesive to seep from the recess 36 into the tiny gap between the inner surface 33a of the large diameter portion 33 and the outer surface 39c of the lead wire 39, thereby joining the brush base 31 and the lead wire 39, the recess 36 can prevent or inhibit the adhesive from spreading to the area outside the recess 36.

[0056] As described above in detail, with the brush base 31 and motor 100 of this embodiment, even if the lead wires 38, 39 are relatively thick and thin, one insertion hole 35 can accommodate them, and they can be lightly press-fitted into the brush base 31 and held in the brush base 31. Therefore, with the brush base 31 of this embodiment, it is not necessary to prepare dedicated brush bases with insertion holes of different thicknesses formed for the lead wires 38, 39 of different thicknesses.

[0057] Of the two portions of different thickness formed in the insertion hole 35, the inner diameter of the small diameter portion 34 must be an inner diameter corresponding to the outer diameter of the relatively thin lead wires 38, 39, but in addition, the inner diameter must be large enough to allow the core wires 38a, 39a of the relatively thick lead wires 38, 39 inserted into the large diameter portion 33 to pass through.

[0058] Although the brush base 31 of this embodiment is adapted to accommodate two different thicknesses of lead wires 38, 39, the brush base for a brushed motor and the brushed motor of the present invention may have insertion holes formed with three or more different thicknesses to accommodate three or more different thicknesses of lead wires. In this case, the insertion holes must be formed so that the inner diameters of the insertion holes become smaller from the side where the lead wires are inserted.

[0059] Furthermore, the brush base 31 of this embodiment has portions with different inner diameters (large diameter portion 33 and small diameter portion 34) formed side by side in the axial direction C2 in a single insertion hole, but the brush base for a brush motor and brush motor of the present invention are not limited to those having portions with different inner diameters formed side by side in the axial direction in a single insertion hole.

[0060] That is, the brush base for a brush motor and the brush motor according to the present invention may have a plurality of insertion holes with different inner diameters formed at different positions on the surface of the brush base. In the case of such a brush base, it is sufficient to select one of the plurality of insertion holes corresponding to the thickness of the lead wire to be inserted and insert the lead wire into it, and the remaining insertion holes that were not selected may be blocked with a plug, adhesive, or the like. Note that, depending on the environment in which the brush motor is used, the remaining insertion holes that were not selected may not be blocked.

[0061] In the brush base 31 of this embodiment, a tapered surface 35b is formed at the boundary between the large diameter portion 33 and the small diameter portion 34, and a tapered surface 35a is also formed at the boundary between the large diameter portion 33 and the outer surface 31a. However, the brush base of the present invention is not limited to one having these tapered surfaces 35b, 35a formed thereon, and does not necessarily have tapered surfaces 35b, 35a formed thereon.

[0062] In the brush base 31 of this embodiment, a protrusion 37 that covers part of the opening of the small diameter portion 34 on the outlet side in the insertion direction of the lead wires 38, 39 is formed, but the brush base of the present invention is not limited to one having a protrusion 37 formed thereon, and may not have a protrusion 37 formed thereon.

[0063] In the brush base 31 of this embodiment, a recessed depression 36 is formed in the opening on the inner surface 31b of the brush base 31 facing the insertion hole 35 (the opening on the exit side in the insertion direction of the lead wires 38, 39). However, the brush base of the present invention is not limited to one having a depression 36 formed therein, and may not have a depression 36 formed therein. [Explanation of symbols]

[0064] 10 stator assembly 20 rotor assembly 30 Brush base assembly 31 Brush stand 31a External surface 31b Inside 33 Large diameter section 34 Small diameter section 35 Insertion hole 38,39 Lead wire 100 brushed motor C1,C2 axis

Claims

1. an insertion hole is formed through the outer surface to the inner surface, into which a lead wire connected to a brush of a brush motor from the outer surface side is inserted; the insertion holes are formed with thicknesses corresponding to the thicknesses of a plurality of types of lead wires having different thicknesses preset as lead wires to be inserted; the insertion hole is formed with portions of different thicknesses corresponding to the thicknesses of a plurality of types of lead wires, the portions being aligned in an axial direction of the insertion hole such that the thicknesses gradually decrease from the insertion side in an insertion direction of the lead wires, The insertion hole has a step formed at the boundary portion where the thickness changes, against which a tip end of a lead wire having a relatively large thickness among a plurality of types of lead wires having different thicknesses abuts, a protrusion is formed at an opening of the insertion hole on the exit side in the lead wire insertion direction, the protrusion closing a part of the opening and contacting a tip end of the smallest lead wire among a plurality of types of lead wires having different thicknesses; The protrusion covers only a portion of the opening that is biased toward the connection portion between the brush and the lead wire from the axis of the insertion hole.

2. 2. The brush base for a brushed motor according to claim 1, wherein the step portion has a tapered surface formed thereon such that the inner diameter changes continuously before and after the change in thickness.

3. 3. The brush base for a brushed motor according to claim 1, wherein a recess is formed in an opening of the inner surface facing the insertion hole.

4. 4. The brush base for a brushed motor according to claim 3, wherein the recess surrounds the opening.

5. a stator assembly, a rotor assembly, and a brush base assembly; The brush base assembly is a brush motor having a brush base as described in any one of claims 1 to 4, a brush fixed to the inner surface side of the brush base, and a lead wire inserted from the outer surface side into an insertion hole that penetrates from the outer surface of the brush base to the inner surface and connected to the brush on the inner surface side.

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