CN111668975A - Motor with a stator having a stator core - Google Patents

Abstract

The invention provides a motor which improves the insulation between a motor box and a brush set. The motor of the present invention comprises: an iron motor case (10), a bottomed cylindrical resin brush base (50), a bracket (40), and a brush group (80) having a power supply terminal (81 b). The bracket (40) is fixed to the inside of the motor case (10). An opening end portion (51a) of the brush base is fixed to the bracket (40) from the outside of the motor case (10). The power supply terminal (81b) protrudes radially outward from the outer peripheral surface (10a) of the motor case. A first insulator (70) is disposed between the open end (11a) of the motor case and the brush group (80).

Description

Motor with a stator having a stator core

Technical Field

The present invention relates to a small motor.

Background

For example, an electric motor of patent document 1 includes: a steel housing (motor case); an end cap (brush base) fitted to the steel housing; a brush assembly (brush set) mounted to the end cap; and a rotor having a commutator connected to the brush assembly.

One end of the brush device is connected to the commutator, and the other end of the brush device serves as a connection terminal with the outside. Further, the brush device is held so as not to contact the steel case by a protruding portion provided on a side wall of the end cap.

Documents of the prior art

Patent document 1 Japanese Kokai Sho 63-182666

Disclosure of Invention

Problems to be solved by the invention

However, in the electric motor of patent document 1, when the protruding portion of the end cap is deformed when the electric motor is used in a place where vibration is applied during traveling, such as in a vehicle, the other end of the brush device may come into contact with the steel case, which may cause insulation failure.

Means for solving the problems

Accordingly, the present invention provides a motor having improved insulation between a motor case and a brush group.

The first motor of the present invention includes: a motor case made of iron and having a cylindrical shape with a cover having an open end; a bottomed cylindrical resin brush base having an opening end; an annular bracket; and a brush group having a power supply terminal, the bracket being fixed to an inner side of the motor case, an opening end portion of the brush base being fixed to the bracket from an outer side of the motor case, the brush group being fixed to the brush base, the power supply terminal protruding radially outward of an outer peripheral surface of the motor case, and a first insulator being disposed between the opening end portion of the motor case and the power supply terminal.

The second motor of the present invention includes: a motor case made of iron and having a cylindrical shape with a cover having an open end; a bottomed cylindrical resin brush base having an opening end; and a brush group having a power supply terminal, an opening end portion of the brush base being fixed to an inner side of the motor case, the brush group being fixed to the brush base, the power supply terminal protruding radially to an outer side of an outer peripheral surface of the motor case, a first insulator being disposed between the opening end portion of the motor case and the power supply terminal.

The third motor of the present invention includes: a motor case made of iron and having a cylindrical shape with a cover having an open end; a bottomed cylindrical resin brush base having an opening end; an annular iron bracket; and a brush group, the bracket being fixed to an inner side of the motor case, an open end portion of the brush base being fixed to the bracket from an outside of the motor case, the brush group being fixed to the brush base, and a second insulator being disposed between the bracket and the brush group.

Effects of the invention

According to the first motor of the present invention, the first insulator is disposed between the open end of the motor case and the power supply terminal, and therefore, the motor case and the brush group can be reliably insulated from each other.

According to the second motor of the present invention, since the first insulator is disposed between the open end of the motor case and the power supply terminal, the motor case and the brush group can be reliably insulated from each other.

According to the third motor of the present invention, since the second insulator is disposed between the bracket and the brush group, the bracket and the brush group can be reliably insulated from each other.

Drawings

Fig. 1 is a sectional view of a motor according to a first embodiment of the present invention.

Fig. 2 is an exploded perspective view of the motor of fig. 1.

Fig. 3 is an exploded perspective view of the motor of fig. 1, viewed from a different direction than fig. 2.

Fig. 4 is a first assembled perspective view of the motor of fig. 1.

Fig. 5 is a second assembled perspective view of the motor of fig. 1.

Fig. 6 is an exploded perspective view of a motor according to a second embodiment of the present invention.

Fig. 7 is an exploded perspective view of a motor according to a second embodiment of the present invention, viewed from a different direction from that of fig. 6.

Fig. 8 is an exploded perspective view of a motor according to a third embodiment of the present invention.

Fig. 9 is an exploded perspective view of a motor according to a third embodiment of the present invention, viewed from a different direction from that of fig. 8.

Fig. 10 is an exploded perspective view of a motor according to a fourth embodiment of the present invention.

Fig. 11 is an exploded perspective view of a motor according to a fourth embodiment of the present invention, viewed from a different direction from fig. 10.

Fig. 12 is a sectional view of a motor according to a fifth embodiment of the present invention.

Fig. 13 is an exploded perspective view of the motor of fig. 12.

Fig. 14 is an exploded perspective view of the motor of fig. 12, viewed from a direction different from that of fig. 13.

In the figure:

1 Motor

10 motor box

Outer peripheral surface of 10a motor case

10b inner peripheral surface of motor case

11 cylindrical part of motor case

11a open end of motor case

11b step part at the opening end of the motor case

11ba is located on the inner peripheral surface of the step part of the opening end part of the motor case

11c space part

12 upper cover of motor box

13 inner space part of motor box

16 radial bearing

18 magnet for driving

20 rotor

21 armature core

22 copper wire

30 rotating shaft

31 commutator

40 bracket

40a outer peripheral surface of the bracket

40b lower surface of the bracket

Inner peripheral surface of 40c bracket

41 through hole of bracket

42 support through hole

43 insert into the hole

50 Brush base

Outer peripheral surface of 50a brush base

51 cylindrical part of brush base

51a brush base open end

51b step part

Inner bottom surface of 51ba step part

51c Brush Slot

51d supporting projection

51e fixing projection

Bottom cover of 52 brush base

52a through hole

53 space part

56 radial bearing

60 second insulator

61 insulating sheet

62 adhesive material

70 first insulator

71 insulating coating

80 electric brush set

81 electric brush

One end of 81a brush

81b other end of the brush (Power supply terminal)

82 fixed terminal

100 motor

160 second insulator

161 insulating sheet

162 bonding material

200 motor

240 bracket

241 through hole

260 second insulator

261 projection part

300 motor

350 brush base

351b step part

351ba insertion hole

360 second insulator

361 projection

400 motor

450 brush base

450a brush base outer peripheral surface

451 Brush base cylindrical part

451a brush base

Bottom cover of 452 electric brush base

Detailed Description

In the present description, in fig. 1 and 12, a direction parallel to the rotary shaft 30 of the motor is referred to as an "axial direction", a radial direction about the rotary shaft 30 is referred to as a "radial direction", and a rotational direction of the rotary shaft 30 is referred to as a "circumferential direction".

In fig. 1 and 12, the upward direction is simply referred to as "upper" and "upper", and the downward direction is simply referred to as "lower" and "lower". The vertical direction does not indicate a positional relationship or a direction when the device is actually incorporated.

Hereinafter, embodiments of the present invention will be described by way of example based on the drawings.

(first embodiment example)

Fig. 1 to 5 are views for explaining the brush-equipped motor 1 of the present example.

The motor 1 includes a motor case 10, a driving magnet 18, a rotor 20, a rotary shaft 30, a commutator 31, a bracket 40, a brush base 50, and a brush group 80.

The motor case 10 is formed of a rigid, magnetic, and electrically conductive iron material, and has a covered cylindrical shape including a cylindrical portion 11 and an upper cover 12 integrally formed with an upper end of the cylindrical portion 11. The lower end opening end portion 11a of the cylindrical portion 11 of the motor case 10 is formed in a flat shape. A through hole is formed in the center of the upper cover 12, and a radial bearing 16 is press-fitted into the through hole.

A step portion 11b having a diameter slightly larger than that of the inner peripheral surface 10b of the motor case is formed over the entire circumference on the inner peripheral surface near the opening end of the motor case 10. A bracket 40 is fixed to the step portion 11 b.

The bracket 40 is formed of a rigid, magnetic, and electrically conductive iron material, and is formed in a hollow plate shape having a through hole 41 through which the rotary shaft 30 passes. The lower surface 40b of the bracket becomes a plane.

The bracket 40 has a ring shape, and has the same outer diameter and inner diameter at the center.

The outer peripheral surface 40a of the bracket 40 and the inner peripheral surface 11ba of the stepped portion 11b have the same size.

The height of the bracket 40 in the axial direction is slightly lower than the height of the step portion 11b in the axial direction.

When the bracket 40 is fixed to the step portion 11b, the opening end portion 11a of the motor case slightly protrudes axially downward from the lower surface 40b of the bracket. The opening end 11a of the motor case is crimped to the outer peripheral surface 40a of the bracket, and the bracket 40 is fixed to the opening end 11a of the motor case. At this time, the outer peripheral surface 40a of the bracket and the step portion 11b are in a state without a gap therebetween. Thus, the bracket 40 is fixed to the inside of the motor case 10.

The driving magnet 18 is formed in a cylindrical shape magnetized to have N and S poles alternately in the circumferential direction. The drive magnet 18 may be fixed by fixing a cylindrical magnet to the inner peripheral surface 10b of the cylindrical portion of the motor case with an adhesive or by bending a rectangular rubber magnet into a cylindrical shape.

The rotor 20 includes an armature core 21 formed by laminating a plurality of thin steel plates and a copper wire 22 wound in a coil shape around the armature core 21.

The rotary shaft 30 has a commutator 31 and is fixed to the center of the armature core 21 of the rotor 20.

The commutator 31 is electrically connected to the copper wire 22.

The rotary shaft 30 rotates integrally with the rotor 20.

The rotary shaft 30 is inserted through a radial bearing 16 fixed to the motor case 10 and is rotatably supported. One end of the rotating shaft 30 protrudes from the motor case 10. The other end of the rotating shaft 30 is supported by a radial bearing 56 fixed to the brush base 50 and a thrust bearing described later.

The brush base 50 is formed of a nonmagnetic hard resin material, has a bottomed cylindrical shape having a cylindrical portion 51 and a bottom cover 52 integrally formed with a lower end of the cylindrical portion 51, and has a space portion 53 formed inside the cylindrical portion 51.

A circular recess is formed in the center of the bottom cover 52 of the brush base 50, and the bottom surface of the recess serves as a thrust bearing. A radial bearing 56 is press-fitted into the recess.

The brush base 50 is fixed to the bracket 40 from the outside of the motor case 10. An upper end opening end portion 51a of the cylindrical portion 51 of the brush base 50 is formed in a flat shape. The flat surface of the open end 51a of the brush base is fixed in direct contact with the flat surface of the lower surface 40b of the bracket 40. Further, the open end 51a of the brush base 50 is not in contact with the open end 11a of the motor case.

When the brush base 50 is fixed to the bracket 40, the space 53 communicates with the internal space 13 of the motor case through the through hole 41 of the bracket.

The bottom cover 52 of the brush base is disposed to protrude downward from the opening end portion 11a of the motor case.

The outer peripheral surface 50a of the brush base is formed slightly smaller than the outer peripheral surface 40a of the bracket.

The inner peripheral surface of the cylindrical portion 51 of the brush base is formed larger than the inner peripheral surface 40c of the bracket.

In the space 53, a pair of brush groups 80 is provided so as to be in sliding contact with the commutator 31 and to allow current to flow to the copper wire 22. The pair of brush groups 80 are disposed inside the motor case 50 in line symmetry about the rotation shaft 30.

The brush group 80 has a brush 81 for supplying current from an external power supply to the commutator 31 and a fixed terminal 82 for fixing the brush 81 to the brush base 50.

The brush 81 is made of a conductive material having rigidity and elasticity such as copper or a copper alloy. The brush 81 has a flat surface and a side surface narrower than the flat surface in width, and is formed in a radially elongated thin plate shape.

The brush 81 has one end 81a of the brush and the other end 81b of the brush which are in sliding contact with the commutator 31.

The other end 81b of the brush is disposed to protrude radially outward from the brush base 50 and to pass over the outer peripheral surface 10a of the motor case, and serves as a power supply terminal of the motor to which power is supplied from an external power supply. The power supply terminal 81b is a male terminal made of metal, which protrudes in the radial direction of the motor, i.e., in the lateral direction. The power supply terminal 81b and the one end 81a of the brush are formed of the same member without a seam.

The fixed terminal 82 has an axially elongated shape made of a rigid conductive material made of iron or a copper alloy such as brass. The fixed terminal 82 is formed as a separate member from the brush 81. The upper portion of the fixed terminal 82 is fixed by caulking or welding to a substantially central portion of the radially elongated brush 81, and is electrically connected to the brush 81. The upper end of the fixed terminal 82 is at the same height as the upper end of the brush 81.

Next, a method of fixing the brush set 80 will be described.

As shown in fig. 3, a stepped portion 51b is formed at the opening end portion 51a of the brush base 50 so as to be lower than the opening end portion 51a by one step in the axial direction. A brush groove portion 51c for fixing the brush group 80 is formed axially downward in the stepped portion 51 b. The upper end of the brush groove portion 51c is disposed axially below the opening end portion 11a of the motor case.

The brush group 80 is press-fitted into the brush groove portion 51c by a brush press-fitting jig not shown.

When the brush group 80 is press-fitted into the brush groove portion 51c, the fixed terminal 82 is fixed to the brush groove portion 51 c. The lower end of the fixed terminal 82 protrudes downward from the through hole 52a of the bottom cover 52 provided to the brush base.

When the brush group 80 is fixed to the brush base 50, as shown in fig. 1, the power supply terminal 81b protrudes radially outward from the cylindrical portion 51 of the brush base 50. One end 81a of the brush is disposed at a position where it can abut against the commutator 31.

The upper end of the brush group 80 is equal to or less than the upper end of the brush groove 51 c.

Next, a method of fixing the bracket 40 and the brush base 50 will be described.

The bracket 40 is formed with an insertion hole 43 for fixing the brush base 50. The insertion holes 43 are formed at a plurality of locations in the circumferential direction around the rotation shaft 30 with the same diameter.

A fixing projection 51e for insertion into the insertion hole 43 is formed on the opening end 51a of the brush base. The fixing projections 51e are formed at a plurality of locations in the circumferential direction around the rotation shaft 30 with the same diameter.

The fixing projection 51e of the brush base 50 is inserted into the insertion hole 43 of the bracket 40, and the distal end side of the fixing projection 51e is melted by heat welding or the like, whereby the brush base 50 is fixed to the bracket 40.

Further, a support through hole 42 for supporting the drive magnet 18 is formed in the bracket 40. The support through-holes 42 are formed at a plurality of locations in the circumferential direction around the rotary shaft 30 with the same diameter.

A support protrusion 51d for insertion into the support through hole 42 is formed at the open end 51a of the brush base. The supporting protrusions 51d are formed at a plurality of locations in the circumferential direction around the rotation shaft 30 with the same diameter.

When the support projection 51d is inserted into the support through hole 42, the support projection 51d projects into the space 11c located inside the opening end of the motor case. The protruding support projection 51d contacts the lower end of the drive magnet 18 in the axial direction, and supports the drive magnet 18 in the axial direction.

The support projection 51d is formed to be higher than the fixing projection 51e after the heat welding.

The support through-hole 42 is arranged at a circumferentially shifted position with respect to the insertion hole 43.

The support projection 51d is arranged at a position shifted in the circumferential direction with respect to the fixing projection 51 e.

The second insulator 60 is disposed at a position not overlapping the support through-hole 42 and the insertion hole 43 when viewed in the axial direction.

The second insulator 60 is disposed at a position not overlapping the supporting projection 51d and the fixing projection 51e when viewed in the axial direction.

Thus, the bracket 40 is fixed to the brush base 50 to which the brush group 80 is fixed.

Next, the bracket 40 integrating the brush group 80 and the brush base 50 is attached to the motor case 10 having the rotor 20, and the opening end 11a of the motor case is caulked to the outer peripheral surface 40a of the bracket, whereby the motor 1 is completed.

In the motor 1, the conductive motor case 10 is disposed above the brush group 80, and a space is formed between the opening end 11a of the motor case and the upper end of the power supply terminal 81b to ensure insulation. However, when the brush assembly 80 moves upward in the axial direction due to some kind of impact, the brush assembly 80 may contact the motor case 10 and cause insulation failure.

Therefore, in the motor of the present invention, the first insulator 70 is disposed between the opening end portion 11a of the motor case and the power supply terminal 81 b. The first insulator 70 of the present invention is any member having electrical insulation, except for a space.

The first insulator 70 of this example is an insulating coating 71 applied to the open end 11a of the motor case facing the power supply terminal 81 b. The insulating coating 71 is formed to have a thickness of 10 μm to 20 μm by polyimide plating, for example.

Further, a conductive bracket 40 is disposed above the brush group 80, and a space obtained by the step portion 51b is formed between the lower surface 40b of the bracket and the upper end of the brush group 80, thereby ensuring insulation. However, when the brush assembly 80 moves upward in the axial direction due to some kind of impact, the brush assembly 80 may contact the bracket 40 and cause insulation failure.

Therefore, in the motor of the present invention, the second insulator 60 for securing insulation between the bracket 40 and the brush group 80 is disposed on the inner bottom surface 51ba of the stepped portion 51 b. Specifically, the second insulator 60 is disposed between the bracket 40 and the fixed terminal 82. More specifically, the second insulator 60 is disposed so as to cover the entire fixed terminal 82 when viewed axially upward.

The second insulator 60 of the present invention is any member having electrical insulation properties, except for a space.

The second insulator 60 of this example is an insulating sheet 61, and the insulating sheet 61 is attached to the inner bottom surface 51ba of the stepped portion 51b via a double-sided tape or an adhesive, and is made of a resin such as polyethylene terephthalate (PET) or polyimide as a base material. That is, the second insulator 60 is attached to the upper surface of the brush groove portion 51c into which the brush group 80 is pressed.

The outer shape of the second insulator 60 is substantially the same as the inner shape of the step portion 51 b.

As shown in fig. 4, when the second insulator 60 is attached to the inner bottom surface 51ba of the stepped portion 51b via the double-sided tape, the upper surface of the second insulator 60 is at the same height as the open end portion 51a of the brush base.

As shown in fig. 5, a bracket 40 is fixed to an opening end 51a of the brush base to which the second insulator 60 is attached. The conductive bracket 40 is disposed in contact with the upper surface of the second insulator 60. That is, the second insulator 60 is fixed between the bracket 40 and the brush group 80.

As described above, the motor 1 of the present embodiment includes: a motor case 10 made of iron having a lid cylindrical shape with an open end 11a, a brush base 50 made of resin having a bottom cylindrical shape with an open end 51a, an annular bracket 40, and a brush group 80 having a power supply terminal 81 b.

Further, the bracket 40 is fixed to the inside of the motor case 10.

The brush base has an open end 51a fixed to the bracket 40 from the outside of the motor case 10.

The brush assembly 80 is fixed to the brush base 50.

The power supply terminal 81b protrudes outside the outer peripheral surface 10a of the motor case in the radial direction.

A first insulator 70 is disposed between the open end 11a of the motor case and the power supply terminal 81 b.

In this example, when the bracket 40 is fixed to the step portion 11b, the opening end portion 11a of the motor case slightly protrudes axially downward from the lower surface 40b of the bracket. In such a configuration, when the brush assembly 80 moves upward in the axial direction due to some kind of impact, the brush assembly 80 may contact the motor case 10 and cause an insulation failure.

Therefore, in the motor of this example, in order to ensure insulation between the motor case 10 and the brush group 80, the first insulator 70 is disposed between the opening end portion 11a of the motor case and the power supply terminal 81 b. Therefore, the motor of the present example can reliably insulate the motor case 10 from the brush group 80.

Further, when the brush assembly 80 moves upward in the axial direction due to some kind of impact, the brush assembly 80 may contact the bracket 40 and cause insulation failure. Therefore, in the motor 1 of the present example, the second insulator 60 is disposed between the bracket 40 and the brush group 80. Therefore, the motor of the present example can reliably insulate the holder 40 from the brush group 80.

In this example, the iron bracket 40 is fixed to the iron motor case 10. In particular, if the iron bracket and the iron motor case made of the same material are used, the gap between the iron bracket and the iron motor case is substantially constant with respect to the change in the external temperature, the bracket does not move with respect to the motor case, and the outer shape of the motor is not deformed.

In the motor 1 of this example, a stepped portion 51b is formed at the opening end portion 51a of the brush base, and a brush groove portion 51c for fixing the brush group 80 is formed at the stepped portion 51 b. The second insulator 60 is disposed on the stepped portion 51 b.

Thus, the motor of the present example can reliably insulate the holder 40 from the brush group 80.

In the motor 1 of this example, the brush group 80 includes the power supply terminal 81b protruding from the outer peripheral surface of the brush base 50 in the radial direction, and the brush 81 formed of the same member without a seam with the power supply terminal 81 b. The second insulator 60 is disposed between the bracket 40 and the brush 81.

This allows the motor of this example to reliably insulate the bracket 40 from the brush 81.

In the motor 1 of this example, the brush group 80 has a fixed terminal 82 which is a separate member from the brush 81. The second insulator 60 is disposed between the bracket 40 and the fixed terminal 82.

Thus, the motor of the present embodiment can reliably insulate the bracket 40 from the fixed terminal 82.

(second embodiment example)

Next, the structure of the motor 100 according to the second embodiment of the present invention will be described with reference to fig. 6 and 7.

In fig. 6 and 7, the same components as those in fig. 1 to 5 are given the same reference numerals, and the description thereof will be omitted.

In the second embodiment, the insulator disposed between the holder and the brush group is different from that of the first embodiment.

That is, the second insulator 60 of the first embodiment is an insulating sheet 61 attached to the inner bottom surface 51ba of the stepped portion 51b via an adhesive 62.

On the other hand, the second insulator 160 of the second embodiment is an insulating sheet 161 attached to the bracket 40 via an adhesive material 162.

The second insulator 160 is disposed on the step portion 51b and fixed between the bracket 40 and the brush group 80.

The second embodiment also can reliably achieve insulation between the holder 40 and the brush group 80.

(third embodiment example)

Next, a structure of a motor 200 according to a third embodiment of the present invention will be described with reference to fig. 8 and 9.

In fig. 8 and 9, the same components as those in fig. 1 to 7 are given the same reference numerals, and the description thereof will be omitted.

In the third embodiment, an insulator disposed between a holder and a brush group is different from that of the first embodiment.

That is, the second insulator 60 of the first embodiment is an insulating sheet 61 attached to the inner bottom surface 51ba of the stepped portion 51b via an adhesive 62.

On the other hand, the third embodiment is described below, for example.

The bracket 240 is formed with a through hole 241 for fixing the second insulator 260. The second insulator 260 is formed of a molded product of an insulating resin.

A protrusion 261 is formed on the second insulator 260, and the protrusion 261 is fixed to the through hole 241.

The second insulator 260 is disposed on the step portion 51b and fixed between the holder 240 and the brush set 80.

The third embodiment can also reliably achieve insulation between the holder 240 and the brush group 80.

(fourth embodiment example)

Next, a structure of a motor 300 according to a fourth embodiment of the present invention will be described with reference to fig. 10 and 11.

In fig. 10 and 11, the same components as those in fig. 1 to 9 are given the same reference numerals, and the description thereof will be omitted.

In the fourth embodiment, an insulator disposed between a holder and a brush group is different from that of the first embodiment.

That is, the second insulator 60 of the first embodiment is an insulating sheet 61 attached to the inner bottom surface 51ba of the stepped portion 51b via an adhesive 62.

On the other hand, the fourth embodiment is described below, for example.

In the brush base 350, an insertion hole 351ba for fixing the second insulator 360 is formed in the stepped portion 351 b. The second insulator 360 is formed of a molded product of an insulating resin.

A protrusion 361 is formed on the second insulator 360, and the protrusion 361 is fixed to the insertion hole 351 ba.

The second insulator 360 is disposed at the stepped portion 351b and fixed between the bracket 40 and the brush group 80.

The fourth embodiment can also reliably achieve insulation between the holder 40 and the brush group 80.

(fifth embodiment example)

Next, a structure of a motor 400 according to a fifth embodiment of the present invention will be described with reference to fig. 12 and 13.

In fig. 12 and 13, the same components as those in fig. 1 to 11 are given the same reference numerals, and the description thereof will be omitted.

In the fifth embodiment, the member to which the brush base 450 is fixed is different from that of the first embodiment. That is, in the first embodiment, the opening end 51a of the brush base is fixed to the bracket 40 from the outside of the motor case 10, but in the fifth embodiment, the opening end 451a of the brush base 450 is fixed to the inside of the motor case 10 without the above-described bracket.

That is, the motor 400 of the fifth embodiment includes: a motor case 10 made of iron having a lid cylindrical shape with an opening end portion 11a, a brush base 450 made of resin having a bottom cylindrical shape with an opening end portion 451a, and a brush group 80 having a power supply terminal 81 b.

The brush base has an opening end portion 451a fixed to the inside of the motor case 10.

Specifically, the outer peripheral surface 450a of the brush base is set to be the same size as the inner peripheral surface 11ba of the stepped portion 11b of the motor case. When the opening end portion 451a of the brush base is fixed to the motor case stepped portion 11b, the opening end portion 11a of the motor case slightly protrudes axially downward from the opening end portion 451a of the brush base. The opening end 11a of the motor case is crimped to the outer peripheral surface 450a of the brush base, and the brush base 450 is fixed to the opening end 11a of the motor case.

The brush group 80 is fixed to the brush base 450, and the power supply terminal 81b protrudes radially outward of the outer peripheral surface 10a of the motor case.

The first insulator 70 is disposed between the opening end 11a of the motor case and the power supply terminal 81 b.

In the fifth embodiment, the number of components can be reduced by eliminating the bracket as compared with the above-described embodiments, and the insulation between the motor case 10 and the brush group 80 can be reliably achieved.

In the fifth embodiment, the bracket is not provided, and therefore, the second insulator is not provided.

While the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.

In the first to fourth embodiments, the opening end portion 11a of the motor case slightly protrudes axially downward from the lower surface 40b of the bracket. Therefore, in the case where the brush assembly 80 is moved axially upward by a certain impact, the brush assembly 80 may first come into contact with the opening end portion 11a of the motor case 10, and then the brush assembly 80 may come into contact with the conductive bracket 40. Therefore, in the first to fourth embodiments, the first insulator 70 is disposed between the opening end portion 11a of the motor case and the brush group 80, and the second insulators 60, 160, 260, and 360 are disposed between the bracket 40 and the brush group 80, but the present invention is not limited thereto.

For example, the opening end 11a of the motor case may protrude axially downward to a greater extent than the lower surface 40b of the bracket, and only the first insulator 70 may be disposed without the second insulator as long as the brush group 80 is in contact with only the opening end 11a of the motor case 10 even if the brush group 80 moves axially upward due to some impact.

For example, the opening end 11a of the motor case may be positioned axially above the lower surface 40b of the bracket, and only the second insulators 60, 160, 260, and 360 may be disposed without the first insulator as long as the brush group 80 is in contact with only the lower surface of the bracket 40 even if the brush group 80 moves axially upward due to some impact.

In the first to fourth embodiments, the iron bracket 40 is fixed to the iron motor case 10, but the present invention is not limited thereto.

For example, in the case where the motors of the first to fourth embodiments are used in a substantially constant temperature environment, the bracket may be made of resin instead of iron.

In the first embodiment, the second insulator 60 is an insulating sheet, but is not limited thereto.

For example, the second insulator 60 may be provided as an insulating coating applied to the conductive bracket 40. The insulating coating may be formed on the entire surface of the bracket 40, or may be formed only on a portion of the bracket facing the brush group 80. The insulating coating is formed to have a thickness of 10 to 20 μm by, for example, polyimide plating.

The first insulator 70 disposed at the open end 11a of the motor case of the first to fifth embodiments is an insulating coating, but is not limited thereto.

For example, the first insulator 70 may be an insulating sheet made of resin such as polyethylene terephthalate (PET) or polyimide as a base material and attached to the opening end portion 11a of the motor case via a double-sided tape or an adhesive.

Further, the insulating coating as the first insulator 70 of the first to fifth embodiments is applied to the opening end portion 11a of the motor case, but is not limited thereto.

For example, an insulating coating as the first insulator 70 may be applied to the brush 81 opposed to the open end portion 11a of the motor case.

In the above description of the embodiment, the brush group 80 is formed by the brushes and the fixed terminals as separate members, but the brushes and the fixed terminals may be formed by the same member without a seam.

Claims (8)

1. A motor is provided with:

a motor case made of iron and having a cylindrical shape with a cover having an open end;

a bottomed cylindrical resin brush base having an opening end;

an annular bracket; and

a brush set having a power supply terminal,

the bracket is fixed on the inner side of the motor box,

an opening end portion of the brush base is fixed to the bracket from outside of the motor case,

the brush set is fixed on the brush base,

the power supply terminal protrudes radially outside the outer peripheral surface of the motor case,

a first insulator is disposed between the open end of the motor case and the power supply terminal.

2. A motor is provided with:

a motor case made of iron and having a cylindrical shape with a cover having an open end;

a bottomed cylindrical resin brush base having an opening end; and

a brush set having a power supply terminal,

the open end of the brush base is fixed to the inside of the motor case,

the brush set is fixed on the brush base,

the power supply terminal protrudes radially outside the outer peripheral surface of the motor case,

a first insulator is disposed between the open end of the motor case and the power supply terminal.

3. The motor according to claim 1 or 2,

the first insulator is an insulating coating applied to an open end of the motor case.

4. A motor is provided with:

a motor case made of iron and having a cylindrical shape with a cover having an open end;

a bottomed cylindrical resin brush base having an opening end;

an annular iron bracket; and

the electric brush group is provided with a brush group,

the bracket is fixed on the inner side of the motor box,

an opening end portion of the brush base is fixed to the bracket from outside of the motor case,

the brush set is fixed on the brush base,

a second insulator is disposed between the bracket and the brush group.

5. The motor of claim 4,

a brush base stepped portion formed by descending downward is formed at the opening end portion of the brush base,

a brush groove part is formed on the brush base stepped part,

the brush group is fixed on the brush groove part,

the second insulator is disposed on the brush base step.

6. The motor of claim 5,

the brush set has a power supply terminal protruding from the outer peripheral surface of the brush base in the radial direction and a brush formed of the same member without a seam with the power supply terminal,

the second insulator is disposed between the bracket and the brush.

7. The motor of claim 6,

the brush set has a fixed terminal which is a different part from the brush,

the second insulator is disposed between the bracket and the fixed terminal.

8. The motor according to any one of claims 5 to 7, wherein

The second insulator is an insulating sheet attached to the inner bottom surface of the brush base stepped portion via an adhesive material.

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