JP2019134643A - Commutator and brushed motor with the same - Google Patents

Abstract

To solve the problem in which a ditch that accumulates wear powder on an insulating base is difficult to function.SOLUTION: The commutator includes: an insulating base 47 whose outer peripheral surface has a substantially circular cross-section; and a commutator piece 49 disposed on an outer peripheral surface 47a of the insulating base and through a gap 49e in a circumferential direction. The commutator piece 49 has an arc portion 49a and a terminal portion 49d. The arc portion 49a has an outer peripheral surface 49b with which a brush 33 is in sliding contact and an inner peripheral surface 49c in contact with the outer peripheral surface 47a of the insulating base 47. The insulating base 47 has a ditch 47b at a position corresponding to the gap 49e. In the ditch 47b, a protrusion 48a standing from an inner side to an outer side is formed in a radial direction. The protrusion 48a is formed continuously along the gap 49e in a non-contact state with the commutator piece. A tip of the protrusion 48a exist radially inward from the outer peripheral surface 49b of the arc portion.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a small DC motor with a brush, and more particularly to a commutator of a small DC motor.

  As a commutator of a small DC motor with a brush, for example, a plurality of commutator pieces divided in the circumferential direction are arranged on the outer peripheral surface of a cylindrical insulating base with a predetermined gap therebetween, and face each other. As described above, there is a structure in which a concave groove having the same width as the gap is formed on the insulating base. However, when the operation is performed for a predetermined period, wear powder generated by sliding friction between the commutator and the brush accumulates in the concave grooves between the commutator pieces, causing a problem that the commutator pieces are short-circuited.

  In order to solve this problem, for example, in Patent Document 1, a groove that is wider than the groove is formed, and the first groove that is wider than the gap between the commutator pieces is formed in the groove. A groove and a second groove that is narrower than the first groove, the second groove being arranged at a position corresponding to the gap between the commutator pieces, and the first groove is the second groove Describes a cylindrical commutator disposed adjacent to. According to this cylindrical commutator, the arc generated when the brush crosses the gap between the commutator pieces is less likely to hit the inner wall surface of the first concave groove, thereby preventing carbonization of the insulating base due to arc heat and wear. It is said that even if the powder enters the concave groove, it can be discharged smoothly and the wear powder is difficult to accumulate.

JP 58-212347 A

  However, in the configuration as described above, when the commutator rotates continuously in one direction, the wear powder tends to be unevenly deposited in the concave groove on the opposite side to the rotation direction of the commutator. As a result, the commutator pieces may be short-circuited by wear powder even though there is sufficient space in the concave groove on the rotation direction side of the commutator, and the concave groove of the insulating base may not function sufficiently. is there.

  Therefore, the present invention provides a commutator that can improve the life of the motor and a brushed motor including the commutator.

The first commutator of the present invention is
In a commutator comprising an insulating base whose outer peripheral surface has a substantially circular cross-section, and a plurality of commutator pieces arranged on the outer peripheral surface of the insulating base with a gap therebetween in the circumferential direction,
The commutator piece has an arc portion and a terminal portion,
The arc portion has an outer peripheral surface with which the brush is in sliding contact and an inner peripheral surface in contact with the outer peripheral surface of the insulating base,
The insulating base has a concave groove at a position corresponding to the gap,
In the concave groove, a protrusion is provided standing from the inner side to the outer side in the radial direction,
The protrusion is formed along the gap in a non-contact state with the commutator piece,
The tip of the projection is radially inward from the outer peripheral surface of the arc portion.

The second commutator of the present invention is
In a commutator comprising an insulating base whose outer peripheral surface is circular in cross section, and a plurality of commutator pieces arranged on the outer peripheral surface of the insulating base with a gap therebetween in the circumferential direction,
The commutator piece has an arc portion and a terminal portion,
The arc portion has an outer peripheral surface with which the brush is in sliding contact and an inner peripheral surface in contact with the outer peripheral surface of the insulating base,
The insulating base is provided with a protruding portion that extends radially outward from the outer peripheral surface,
The protrusion is formed along the gap in a non-contact state with the commutator piece,
The tip of the protrusion is located radially inward from the outer peripheral surface of the arc portion.

The third commutator of the present invention is
In a commutator comprising a substantially flat insulating base, and a plurality of commutator pieces arranged on one side of the insulating base with a gap therebetween in the circumferential direction,
The commutator piece has a contact portion with which the brush is in sliding contact, and a terminal portion,
The insulating base has a concave groove at a position corresponding to the gap,
The concave groove is formed with a protrusion standing from the inside to the outside,
The protrusion is formed along the gap in a non-contact state with the commutator piece,
The tip of the protrusion is on the inner side of the outer surface of the contact portion.

The fourth commutator of the present invention is
In a commutator comprising a flat insulating base, and a plurality of commutator pieces arranged on one side of the insulating base with a gap therebetween in the circumferential direction,
The commutator piece has a contact portion with which the brush is in sliding contact, and a terminal portion,
A protrusion is formed on one side of the insulating base,
The protrusion is formed along the gap in a non-contact state with the commutator piece,
The tip of the protrusion is on the inner side of the outer surface of the contact portion.

  The motor with a brush according to the present invention includes the commutator.

  In the first commutator, since the protrusion is formed along the gap in a non-contact state with the commutator piece, the wear powder entering the groove is divided in the circumferential direction by the protrusion, and the wear powder is recessed. It becomes difficult to deposit on one side of the groove. As a result, it is possible to prevent a short circuit between the commutator pieces due to wear powder in a state where there is sufficient space in the concave groove on the rotation direction side of the commutator. Therefore, the space in the concave groove can be used more effectively than in the configuration as in the conventional example, the time until the short circuit between the commutator pieces due to wear powder can be extended, and the life is improved.

  Further, in the second commutator, the protrusion is formed along the gap in a non-contact state with the commutator piece, so that the wear powder entering the gap is divided in the circumferential direction by the protrusion and the wear powder is generated. It becomes difficult to deposit on one side of the gap. Therefore, the present invention provides a commutator piece made of wear powder as compared with a commutator in which the outer peripheral surface is circular in cross section and the commutator piece is arranged in the circumferential direction on an insulating base having no protrusion on the outer peripheral surface. The time until the short circuit can be slightly extended, and the life is improved.

  Further, in the third commutator, since the protrusion is formed along the gap in a non-contact state with the commutator piece, the wear powder entering the concave groove is divided in the circumferential direction by the protrusion and the wear powder. However, it is difficult to deposit on one side of the groove. As a result, it is possible to prevent a short circuit between the commutator pieces due to wear powder in a state where there is sufficient space in the concave groove on the rotation direction side of the commutator. Therefore, the space in the concave groove can be used more effectively than in the configuration as in the conventional example, the time until the short circuit between the commutator pieces due to wear powder can be extended, and the life is improved.

  Further, in the fourth commutator, since the protrusion is formed along the gap in a non-contact state with the commutator piece, the wear powder entering the gap is divided in the circumferential direction by the protrusion and the wear powder is generated. It becomes difficult to deposit on one side of the gap. Therefore, in the present invention, compared to the commutator in which the commutator pieces are arranged in the circumferential direction on a flat insulating base having no protrusions on the outer surface, the short circuit between the commutator pieces due to wear powder is reduced. Time can be extended slightly and life is improved.

  Moreover, if it is a motor with a brush provided with the above-mentioned commutator, the motor with a brush which can improve a lifetime will be obtained.

It is sectional drawing which shows typically the motor with a brush which concerns on the 1st Example of this invention. 1A is a partial plan view of an arrow AA, and FIG. 1B is a front view of an arrow BB. It is the elements on larger scale of arrow CC of Drawing 2 (a). It is the elements on larger scale of the commutator which concerns on the 2nd Example of this invention. It is the elements on larger scale of the commutator which concerns on the 3rd Example of this invention. It is the elements on larger scale of the commutator which concerns on the example of 4th Embodiment of this invention. It is sectional drawing which shows typically the motor with a brush which concerns on the 5th Example of this invention. 7A is a commutator 146 illustrated in FIG. 7, in which FIG. 7A is a partial plan view of an arrow DD, and FIG. 7B is a front view of an arrow EE of FIG. It is the elements on larger scale of the arrow FF of FIG.8 (b). It is the elements on larger scale of the commutator which concerns on the 6th Example of this invention. It is the elements on larger scale of the commutator which concerns on the example of 7th Embodiment of this invention. It is the elements on larger scale of the commutator which concerns on the example of 8th Embodiment of this invention. It is the elements on larger scale of the commutator which concerns on the modification 1 of this invention. It is a front view of the commutator which concerns on the modification 2 of this invention. It is the elements on larger scale of the commutator which concerns on the modification 3A of this invention. It is the elements on larger scale of the commutator which concerns on the modification 3B of this invention. It is a front view of a commutator concerning modification 4A of the present invention. It is the elements on larger scale of the commutator which concerns on the modification 5 of this invention. It is a fragmentary top view of the commutator which concerns on the modification 6 of this invention. It is the elements on larger scale of the commutator which concerns on the modified example 7A of this invention. It is the elements on larger scale of the commutator which concerns on the modification 7B of this invention. It is a fragmentary top view of the commutator which concerns on the modification 8A of this invention.

In this specification, the direction parallel to the rotating shaft 41 in FIGS. 1 and 7 is referred to as “axial direction”, the radial direction around the rotating shaft 41 is simply referred to as “radial direction”, and the rotational direction of the rotating shaft 41 is Is called “circumferential direction”.
Note that the vertical direction does not indicate the positional relationship or direction when incorporated in an actual device.

  Hereinafter, embodiments of the present invention will be exemplarily described based on the drawings.

(First embodiment)
FIG. 1 is a cross-sectional view of a brushed motor 1 according to this example. As shown in FIG. 1, the brushed motor 1 includes a casing 10 having a stator 34 attached to an inner peripheral surface thereof, and a rotor 40 disposed inside the casing 10.

  The casing 10 includes a housing 20 that is formed of a metal material in a bottomed hollow cylindrical shape, and a bracket 30 that is fitted into an opening of the housing 20 and also serves as a bearing housing formed of an insulating material such as resin.

The housing 20 includes a cylindrical portion 21a and a bottom plate 21b, and a radial bearing 22 is press-fitted into the central portion of the bottom plate 21b.
A circular recess 31 is formed at the center of the bracket 30, and the bottom surface of the recess 31 is a thrust bearing. A radial bearing 32 is press-fitted into the recess 31.

  The stator 34 is fixed to the inner peripheral surface of the cylindrical portion 21a, and is formed of a permanent magnet having a cylindrical shape and alternately magnetized with N and S poles along the circumferential direction.

The rotor 40 includes a rotating shaft 41, an armature core 42 formed by laminating a plurality of thin steel plates attached to the rotating shaft 41, a copper wire 43 wound around the armature core 42 in a coil shape, copper And a commutator 46 electrically connected to the line 43.
The rotor 40 is rotatably supported on a rotating shaft 41 by radial bearings 22 and 32. One end of the rotating shaft 41 protrudes from the casing 10 and the other end is supported by a thrust bearing.

The bracket 30 is provided with a brush 33 so that the commutator 46 is in sliding contact with the commutator 46 at a predetermined pressure to flow current. In FIG. 2, two brushes 33 are provided point-symmetrically around the rotation shaft 41. The tip of the brush 33 has a fork shape divided from the tip, and has a flat contact portion 33 a that contacts the commutator 46. The contact portion 33a has a quadrangular shape as indicated by the dotted line in FIG. 2B, and the axial distance of the contact portion 33a is greater than the distance from the upper end to the lower end of the arc portion 49a of the commutator piece described later. It is short. Further, the distance in the direction orthogonal to the axial direction of the contact portion 33a is formed longer than the width of a gap 49e between commutator pieces, which will be described later, and the contact portion 33a can be in sliding contact with the adjacent commutator pieces 49 simultaneously. Is.
Terminals 33b electrically connected to the brushes 33 are attached to the bracket 30 and protrude outward.

  The commutator 46 that is a feature of the present invention will be described with reference to FIGS. 2 and 3 in particular.

  The commutator 46 includes an insulating base 47 and three commutator pieces 49.

  The insulating base 47 is molded using a thermoplastic resin. The outer peripheral surface 47a of the insulating base has a substantially circular cross section when viewed in a cross section orthogonal to the axial direction shown in FIG.

The commutator piece 49 is made of a conductor and has a circular arc portion 49a having a C-shaped cross section along the outer peripheral surface 47a of the insulating base, and a terminal portion 49d to which the end of the copper wire 43 is electrically connected. .
The arcuate portions 49a of the three commutator pieces are disposed with a gap 49e therebetween so as to form a cylindrical shape surrounding the insulating base 47 in the circumferential direction. The arc portion 49a has a radially outer peripheral surface 49b in which the brush contact portion 33a is in sliding contact and a radially inner peripheral surface 49c in contact with the outer peripheral surface 47a of the insulating base. The outer peripheral surface 49b of the arc portion is arranged concentrically with the outer peripheral surface 47a of the insulating base. Specifically, the center of curvature of the outer peripheral surface 49 b of the arc portion is located on the center line of the rotation shaft 41. The commutator piece 49 is called a cylindrical shape because the commutator piece 49 with which the brush contact portion 33a is in sliding contact is arranged in a cylindrical shape around the rotation axis.

  A gap 49e between adjacent commutator pieces has the same width parallel to the axial direction and is continuously formed from the upper end to the lower end of the arc portion 49a.

  A groove 47b is formed at the position of the insulating base 47 corresponding to the gap 49e between adjacent commutators. The concave groove 47b is formed continuously from the upper end to the lower end of the arc portion 49a along the gap 49e with the same width in FIG. 2B. In FIG. 3, the concave groove 47b is formed so as to open outward in the radial direction, and has a bottom surface 47b1 having a width larger than the width of the gap 49e and a side surface 47b2 having a predetermined depth. Further, the concave groove 47 b is formed symmetrically with respect to a line 51 that passes through the center in the circumferential direction of the gap 49 e and is orthogonal to the axis of the rotation shaft 41.

  Further, a protrusion 48a (or a protrusion) is integrally provided on the radially outer side from the inner side of the concave groove 47b. The protrusion 48a is arranged at a position corresponding to (or facing) the gap 49e. That is, in FIG. 2B, the protrusion 48a is continuously formed from the upper end (one end) to the lower end (the other end) of the arc portion 49a along the gap 49e.

  The protrusion 48a is erected at the center in the circumferential direction of the gap 49e. Specifically, the protrusion 48 a is formed symmetrically with respect to a line 51 that passes through the circumferential center of the gap 49 e and is orthogonal to the axis of the rotation shaft 41.

  The cross-sectional shape of the protrusion 48a is triangular in this example so as to separate the wear powder in the circumferential direction. In addition, if the cross-sectional shape of the protrusion 48a is a shape suitable for separating the abrasion powder in the circumferential direction, a trapezoidal shape, a rectangular shape, or the like can be appropriately selected. Unless otherwise specified, the wear powder of the present invention includes mechanical wear powder generated by sliding frictional resistance between the brush and the commutator piece and electrical wear powder generated by sparks when the commutator piece is switched. Shall be included.

  The protrusion 48a is not in contact with the adjacent arc part 49a, and at least the tip of the protrusion 48a is visible from the gap 49e when viewed from the outside in the radial direction.

  The tip of the protrusion 48a is formed radially inward from the outer peripheral surface 49b of the arc portion so as not to protrude outward in the radial direction from the outer peripheral surface 49b of the arc portion. That is, the radius from the center of the rotating shaft 41 to the tip of the protrusion 48a is smaller than the radius of the outer peripheral surface 49b of the arc portion from the center of the rotating shaft 41.

  Further, the tip of the protrusion 48a is formed radially inward from the outer peripheral surface 47a of the insulating base so that the protrusion 48a of the single insulating base 47 is not deformed by an external force when the motor is assembled. Yes. That is, the radius from the center of the rotating shaft 41 to the tip of the protrusion 48a is smaller than the radius of the outer peripheral surface 47a of the insulating base from the center of the rotating shaft 41. That is, the tip of the protrusion 48a is formed radially inward from the inner peripheral surface 49c of the arc portion.

As described above, the commutator 46 of the present example includes the insulating base 47 whose outer peripheral surface is substantially circular in cross section, and the three commutators 46 disposed on the outer peripheral surface 47a of the insulating base and spaced from each other via the gap 49e. The commutator piece 49 is provided.
The commutator piece 49 has an arc portion 49a and a terminal portion 49d.
The arc portion 49 a has an outer peripheral surface 49 b in which the brush 33 is in sliding contact and an inner peripheral surface 49 c in contact with the outer peripheral surface 47 a of the insulating base 47.
The insulating base 47 has a concave groove 47b at a position corresponding to the gap 49e.
The concave groove 47b is formed with a protrusion 48a standing from the inner side to the outer side in the radial direction.
Further, the protrusion 48 a is continuously formed along the gap 49 e in a non-contact state with the commutator piece 49.
The tip of the projection 48a is radially inward from the outer peripheral surface 49b of the arc portion.

As described above, since the protrusions are continuously formed along the gap in a non-contact state with the commutator piece, the wear powder entering the recessed grooves is divided in the circumferential direction by the protrusions, and the wear powder is recessed. It becomes difficult to deposit on one side of the groove. As a result, it is possible to prevent a short circuit between the commutator pieces due to wear powder in a state where there is sufficient space in the concave groove on the rotation direction side of the commutator.
Therefore, compared to the conventional example, the space in the concave groove can be used effectively, the time until the short circuit between the commutator pieces due to wear powder can be extended, and the life is improved.

Further, if the tip of the protrusion 48a of the insulating base protrudes from the outer peripheral surface 47a of the insulating base, the protrusion of the single insulating base may be deformed by an external force when the motor is assembled.
On the other hand, when the tip of the protrusion 48a is formed radially inward from the outer peripheral surface 47a of the insulating base, the protrusion of the single insulating base is not deformed by an external force when the motor is assembled. Improve the quality.

  Further, since the protrusion 48a is erected at the center in the circumferential direction of the gap 49e, the wear powder entering the concave groove 47b is easily divided equally in the circumferential direction by the protrusion, and is biased to one of the rotational directions of the concave groove. It becomes difficult to use the space in the groove effectively.

(Second Embodiment)
A commutator of a brushed motor according to a second embodiment of the present invention will be described with reference to FIG. 4, parts that are the same as the parts in FIGS. 1 to 3 are given the same reference numerals, and descriptions of overlapping parts are omitted.

  In the first embodiment, the tip of the protrusion 48a is radially inward from the outer peripheral surface 47a of the insulating base. In the second embodiment, the tip of the protrusion 48b is the outer periphery of the insulating base. It is on the radially outer side than the surface 47a. Specifically, the tip of the protrusion 48b slightly protrudes from the outer peripheral surface 47a of the insulating base.

  In the first embodiment, when all of the wear powder accumulates in the groove, the commutator pieces are short-circuited by the wear powder, but the tip of the protrusion is radially outward from the outer peripheral surface of the insulating base. In this case, the wear powder is separated in the circumferential direction by the protrusions, and the time until the short circuit between the commutator pieces due to the wear powder can be slightly extended, and the life is further improved.

(Third embodiment)
A commutator of a brushed motor according to a third embodiment of the present invention will be described with reference to FIG. 5, parts that are the same as the parts in FIGS. 1 to 4 are given the same reference numerals, and descriptions of overlapping parts are omitted.

  In the second embodiment, the tip of the protrusion 48b is radially outward from the outer peripheral surface 47a of the insulating base, but in the third embodiment, the tip of the protrusion 48c is adjacent to each commutator. It is formed at a position where it does not come into contact with the brush 33 that is in sliding contact with the piece at the same time. That is, the tip of the protrusion 48c of the third embodiment is further protruded radially outward than the tip of the protrusion 48b of the second embodiment, and the brush contact portion 33a is the most radially inward. When positioned, the tip of the protrusion 48c is formed at a height that does not contact the contact portion 33a of the brush.

  In the second embodiment, the time until the short circuit between the commutator pieces due to the abrasion powder can be extended as the tip of the protrusion 48c extends radially outward, but the tip of the protrusion is in contact with the brush. When the commutator is rotated, the protrusion is slidably contacted with the contact portion of the brush and does not contribute to the rotational force of the rotor. Wear powder is added, shortening the service life.

  On the other hand, in this example, the tip of the protrusion 48c is formed at a position where it does not come into contact with the contact part 33a of the brush that is in sliding contact with each adjacent commutator piece at the same time, and the protrusion 48c does not contact with the contact part 33a of the brush Therefore, the protrusion 48c can suppress the generation of mechanical wear powder that does not contribute to the rotational force of the rotor, and can prevent the shortening of the service life.

(Fourth embodiment)
A commutator of a brushed motor according to a fourth embodiment of the present invention will be described with reference to FIG. In FIG. 6, parts that are the same as the parts in FIGS. 1 to 5 are given the same reference numerals, and descriptions of the overlapping parts are omitted.

In the above-described embodiment example, the protrusion is erected along the above-mentioned gap from the inside of the groove of the insulating base to the radially outer side, but in the fourth embodiment example, the protrusion 48d is The insulating base 61 having a circular cross section in which no concave groove is formed on the outer peripheral surface is erected along the gap from the outer peripheral surface to the radially outer side.
Specifically, in the insulating base 61 whose outer peripheral surface has a circular cross section, a protrusion 48d is provided on the insulating base 61 so as to extend radially outward from the outer peripheral surface. The commutator piece is continuously formed in the same shape along the gap in a non-contact state.
The tip of the protrusion 48d is radially inward from the outer peripheral surface 49b of the arc portion. More preferably, the tip of the protrusion 48d is formed at a position where it does not come into contact with the contact portion 33a of the brush that is in sliding contact with adjacent commutator pieces at the same time. That is, when the brush contact portion 33a is positioned at the innermost radial direction, the tip of the protrusion 48d is formed at a height that does not contact the brush contact portion 33a.

  Compared with the first to third embodiment examples, this example has a configuration in which the insulating base does not have a concave groove and wear powder is less likely to accumulate in the gap between the commutator pieces. However, in this example, compared to a commutator in which the outer peripheral surface is circular in cross section and the commutator piece is arranged in the circumferential direction on an insulating base that does not have a protrusion on the outer peripheral surface, the commutator piece due to wear powder The time until the short circuit can be slightly extended, and the life is improved.

(Fifth embodiment)
A brushed motor 100 according to a fifth embodiment of the present invention will be described with reference to FIGS. 7 to FIG. 9, parts that are the same as the parts in FIG. 1 to FIG. 6 are given the same reference numerals, and descriptions of overlapping parts are omitted.

The commutator of the above-described embodiment example is a cylindrical type in which the commutator pieces are arranged in a cylindrical shape around the rotation axis. However, the commutator piece 149 of the fifth embodiment is rotated by the commutator piece 149. It is a flat plate type arranged around a shaft in a flat plate shape.
Further, the tip of the brush 33 in the above-described embodiment example has a flat contact portion 33 a that contacts the commutator 46, but the tip of the brush 133 in the fifth embodiment protrudes to the outside in contact with the commutator 146. It has a curved contact portion 133a.
Further, terminals 133b electrically connected to the brushes 133 are attached to the bracket 30 and protrude outward.

  The commutator 146 includes an insulating base 147 and three commutator pieces 149.

  The insulating base 147 is formed in a substantially flat plate shape using a thermoplastic resin.

The commutator piece 149 has a contact portion 149a that is in sliding contact with the brush and a terminal portion (not shown) to which the end of the copper wire 43 is electrically connected.
The contact portion 149a is made of a substantially triangular conductor in which a copper plate is gold-plated, and is disposed on one outer surface 147a of the insulating base 147 in the circumferential direction with a gap 149e therebetween around the rotation axis.

  Further, the gap 149e between adjacent commutator pieces is continuously formed from the inner side to the outer side in the radial direction of the commutator piece 149 with the same width around the rotation shaft 41 in the direction orthogonal to the axial direction. .

  A groove 147b is formed at the position of the insulating base 147 corresponding to the gap 149e between adjacent commutators. The concave groove 147b is continuously formed from the radially inner side to the outer side of the commutator piece 149 along the gap 149e with the same width.

  In FIG. 7, the concave groove 147b is formed so as to open upward in the axial direction, and has a bottom surface 147b1 having a width larger than the width of the gap 149e and a side surface 147b2 having a predetermined depth. In addition, in FIG. 9, the concave groove 147 b is formed symmetrically with respect to a line 151 that passes through the center in the circumferential direction of the gap 149 e and is parallel to the axis of the rotating shaft 141.

  Further, in FIG. 9, a protrusion 148a (or protrusion) is erected integrally from the inner side of the groove 147b to the upper side in the axial direction. The protrusion 148a is disposed at a position corresponding to (or facing) the gap 149e. That is, the protrusion 148a is formed in the same shape along the gap 149e and continuously from the radially inner side to the outer side of the commutator piece.

  The protrusion 148a is erected at the center in the circumferential direction of the gap 149e in FIG. Specifically, the protrusion 148a is formed symmetrically with respect to a line 151 passing through the center of the gap 149e in the circumferential direction and parallel to the axis of the rotation shaft 141.

  Further, the protrusion 148a is not in contact with the adjacent commutator piece 149, and at least the tip of the protrusion 148a can be seen from the gap 149e.

  Further, the tip of the protrusion 148a is formed on the inner side of the outer surface of the contact part 149a so as not to protrude outward from the outer surface of the contact part 149a.

  Further, the tip of the protrusion 148a is formed on the inner side of the outer surface 147a of the insulation base so that the protrusion 148a of the single insulation base is not deformed by an external force when the motor is assembled.

As described above, the commutator 146 of the present example includes the substantially flat insulating base 147 and the three commutator pieces 149 disposed on the outer surface 147a of the insulating base and disposed in the circumferential direction via the gap 149e. It has.
This commutator piece 149 has a contact portion 149a with which the brush 133 is slidably contacted, and a terminal portion.
The insulating base 147 has a concave groove 147b at a position corresponding to the gap 149e.
The concave groove 147b is formed with a protrusion 148a standing from the inside to the outside.
The protrusion 148a is continuously formed along the gap 149e in a non-contact state with the commutator piece 149.
The tip of the protrusion 148a is on the inner side of the outer surface of the contact portion 149a.

Since such protrusions are continuously formed along the gap in a non-contact state with the commutator piece, the wear powder entering the groove is divided in the circumferential direction by the protrusion, and the wear powder is recessed in the groove. It becomes difficult to deposit on one side. As a result, it is possible to prevent a short circuit between the commutator pieces due to wear powder in a state where there is sufficient space in the concave groove on the rotation direction side of the commutator.
Therefore, compared to the conventional example, the space in the concave groove can be used effectively, the time until the short circuit between the commutator pieces due to wear powder can be extended, and the life is improved.

  Further, if the tip of the protrusion 148a protrudes from the outer surface 147a of the insulating base, the protrusion of the single insulating base may be deformed by an external force when the motor is assembled.

  On the other hand, when the tip of the protrusion 148a is formed on the inner side of the outer surface 147a of the insulating base, the protrusion of the single insulating base is not deformed by an external force when the motor is assembled. The quality of time improves.

  Further, since the protrusion 148a is erected at the center in the circumferential direction of the gap 149e, the wear powder entering the concave groove 147b is easily divided into the circumferential direction by the protrusion and is biased to one of the rotational directions of the concave groove. It becomes difficult to use the space in the groove effectively.

(Sixth embodiment)
A commutator of a brushed motor according to a sixth embodiment of the present invention will be described with reference to FIG. 10, parts that are the same as the parts in FIG. 1 to FIG. 9 are given the same reference numerals, and descriptions of overlapping parts are omitted.

  In the fifth embodiment, the tip of the protrusion 148a is inside the outer surface 147a on one side of the insulating base. However, in the sixth embodiment, the tip of the protrusion 148b is on one side of the insulating base. Outside the outer surface 1447a. Specifically, the tip of the protrusion 148b slightly protrudes from the outer peripheral surface 147a of the insulating base.

  That is, in the fifth embodiment, when all of the wear powder accumulates in the concave groove, the commutator pieces are short-circuited by the wear powder, but the tip of the protrusion 148b is more than the outer surface of the insulating base. When it is on the outside, the wear powder is separated in the circumferential direction by the protrusions, and the time until the short circuit between the commutator pieces due to the wear powder can be slightly extended, and the life is further improved.

(Seventh embodiment)
A commutator of a brushed motor which is a seventh embodiment of the present invention will be described with reference to FIG. In FIG. 11, parts that are the same as the parts in FIGS. 1 to 10 are given the same reference numerals, and descriptions of the overlapping parts are omitted.

  In the sixth embodiment, the tip of the protrusion 148b is outside the outer surface 147a on one side of the insulating base, but in the seventh embodiment, the tip of the protrusion 148c is adjacent to each commutator. It is formed at a position where it does not come into contact with the brush 133 that is in sliding contact with the piece at the same time. That is, when the tip of the protrusion 148c of the seventh embodiment example further protrudes from the tip of the protrusion 148b of the sixth embodiment example, and the brush contact portion 133a falls most into the gap 149e, The tip of the protrusion 148c is formed at a height that does not contact the contact portion 133a of the brush.

  Further, in the sixth embodiment, the time until the short circuit between the commutator pieces due to wear powder can be extended as the tip of the protrusion 148c is extended outward, but the tip of the protrusion is the contact part of the brush. When the commutator rotates, this protrusion slides on the brush contact and does not contribute to the rotational force of the rotor. Adds powder and shortens life.

  On the other hand, in this example, the tip of the protrusion 148c is formed at a position that does not contact the brush contact portion 133a that is in sliding contact with each adjacent commutator piece at the same time, and the protrusion 148c does not contact the brush contact portion 133a. Therefore, the protrusion 148c can suppress the generation of mechanical wear powder that does not contribute to the rotational force of the rotor, and can prevent the shortening of the service life.

(Eighth embodiment)
A commutator of a brushed motor according to an eighth embodiment of the present invention will be described with reference to FIG.
In FIG. 12, parts that are the same as the parts in FIGS. 1 to 11 are given the same reference numerals, and descriptions of overlapping parts are omitted.

  In the fifth to seventh embodiment examples, the protrusion is erected from the inside to the outside of the recessed groove of the insulating base. In the eighth embodiment example, the protrusion 148d is recessed on the outer surface. It is erected on an insulating base having a flat plate shape in which no groove is formed.

Specifically, this example includes a flat insulating base 161 and a plurality of commutator pieces 149 arranged on one side of the insulating base 161 and spaced apart from each other in the circumferential direction. .
The commutator piece 149 has a contact portion in which the brush is in sliding contact and a terminal portion.
A protrusion 148d is formed on one surface of the insulating base.
The protrusion 148d is formed along the gap 149e so as not to contact the commutator piece.

  The tip of the protrusion 148d is on the inner side of the outer surface of the contact portion 149a. More preferably, the tip of the protrusion 148d is formed at a position where it does not come into contact with the contact portion 133a of the brush that is in sliding contact with adjacent commutator pieces at the same time. That is, when the brush contact portion 133a falls most due to the gap 149e, the tip of the protrusion 148d is formed at a height that does not contact the brush contact portion 133a.

  Compared with the fifth to seventh embodiment examples, the present example has a configuration in which the insulating base does not have a concave groove and wear powder is less likely to accumulate in the gap between the commutator pieces. However, in this example, compared to the commutator in which the commutator pieces are arranged in a flat plate shape in the circumferential direction on the flat insulating base having no protrusions on the outer surface, The time until the short circuit can be slightly extended, and the life is improved.

  The embodiment of the present invention has been described above, but the present invention is not limited to the above, and various modifications other than those described above can be implemented without departing from the spirit of the present invention.

(Modification 1)
In the first to fourth embodiments, the protrusion is erected at the center in the circumferential direction of the gap 49e, but is not limited thereto.
For example, as shown in FIG. 13, the protrusion 48e may be erected by moving from the center in the circumferential direction of the gap 49e to either one in the circumferential direction. In other words, the entire protrusion may be moved slightly in the circumferential direction. However, the protrusion 48e is not in contact with the adjacent arc portion 49a, and the tip of the protrusion 48e can be seen from the gap 49e when viewed from the outside in the radial direction.

(Modification 2)
In the first to fourth embodiments, the protrusions are continuously formed on the insulating base along the gap 49e from the upper end to the lower end of the arc portion, but the invention is not limited to this.
For example, as shown in FIG. 14, the protrusion 48 f may be partially erected along the gap 49 e in accordance with the fork-shaped brush 33 whose tip is divided. That is, the protrusion 48f is formed on the insulating base in the axial direction only at the portion where the brush 33 is in sliding contact with the arc portion 49a.

(Modification 3)
In the first to third embodiments, the concave groove has an inner bottom surface having a width larger than the gap width and an inner peripheral surface having a predetermined depth, but is not limited thereto.
For example, as shown in FIG. 15, the concave groove 47c may have an inner bottom surface having the same width as the gap 49e and an inner circumferential surface having a predetermined depth (Modification 3A).
For example, as shown in FIG. 16, the concave groove 47d may have an inner bottom surface smaller than the width of the gap 49e and an inner circumferential surface having a predetermined depth (Modification 3B).

(Modification 4)
In the first to fourth embodiments, the gap between adjacent commutators is formed in parallel to the axial direction, but is not limited thereto.
For example, as shown in FIG. 17, the gap between adjacent commutators may be slightly inclined with respect to the axial direction in order to reduce the generation of wear powder. That is, the slightly slant gap 49f may be applied to the first to third embodiments or the modifications 1 to 3, and the commutator piece 52 and the protrusion 48i corresponding to the slightly slant gap 49f. Is formed (Modification 4A).
Further, this slightly inclined gap may be applied to the fourth embodiment example or the first and second modification examples 1 and 2 (modification example 4B).

(Modification 5)
In the fifth to eighth embodiments, the protrusion is erected at the center in the circumferential direction of the gap 149e. However, the present invention is not limited to this.
For example, as shown in FIG. 18, the protrusion 148e may be erected by moving from the center in the circumferential direction of the gap 149e to either one in the circumferential direction. In other words, the entire protrusion may be moved slightly in the circumferential direction. However, the protrusion 148e is not in contact with the adjacent commutator piece 149, and the tip of the protrusion 148e is completely visible from the gap 149e.

(Modification 6)
In the fifth to eighth embodiments, the protrusions are continuously formed along the gap 149e from the radially inner side to the outer side of the commutator piece. However, the present invention is not limited to this.
For example, as shown in FIG. 19, the protrusion 148 f may be partially erected along the gap 149 e in accordance with the fork-shaped brush 133 whose tip is divided. That is, the protrusion 148f may be formed on the insulating base only at the portion where the brush 133 is in sliding contact with the commutator piece 149.

(Modification 7)
Further, in the fifth to seventh embodiment examples, the concave groove has an inner bottom surface having a width larger than the gap width and an inner peripheral surface having a predetermined depth, but is not limited thereto.
For example, as shown in FIG. 20, the concave groove 147c may have an inner bottom surface having the same width as the width of the gap 149e and an inner circumferential surface having a predetermined depth (Modification 7A).
For example, as shown in FIG. 21, the concave groove 147d may have an inner bottom surface smaller than the width of the gap 149e and an inner circumferential surface having a predetermined depth (Modification 7B).

(Modification 8)
In the fifth to eighth embodiment examples, the gap 149e between adjacent commutator pieces is formed in a direction orthogonal to the axial direction, but is not limited thereto.
For example, as shown in FIG. 22, in order to reduce the generation of wear powder, the gap 149f between adjacent commutators may be slightly inclined with respect to the direction orthogonal to the axial direction. That is, the slightly inclined gap 149f is applied to the fifth to seventh embodiments or the modified examples 5 to 7, and the commutator piece 152 and the protrusion 148i corresponding to the slightly inclined gap 149f are formed. (Modification 8A).
Further, this slightly inclined gap may be applied to the eighth embodiment or its modifications 5 and 6 (modification 8B).

  Moreover, if it is a motor with a brush provided with the above-mentioned commutator, the motor with a brush which improves a lifetime will be obtained.

In addition, although the above-mentioned protrusion is erected integrally from the insulating base, the above-described protrusion may be erected separately from the insulating base.
Moreover, although the above-mentioned commutator piece is three pieces, multiple pieces may be sufficient.

DESCRIPTION OF SYMBOLS 1 Motor with brush 10 Casing 20 Housing 21a Cylindrical part 21b Bottom plate 22 Radial bearing 30 Bracket 31 Recess 32 Radial bearing 33 Brush 33a Contact part 33b Terminal 34 Stator 40 Rotor 41 Rotating shaft 42 Armature core 43 Copper wire 46 Commutator 47 Insulation base 47a Insulation base outer peripheral surface 47b Insulation base concave groove 47b1 Insulation base concave groove bottom face 47b2 Insulation base concave groove side face 48a Insulation base protrusion 49 Commutator piece 49a Arc part 49b Arc outer peripheral surface 49c Arc inner peripheral surface 49d Terminal portion 49e Gap

Claims (12)

In a commutator comprising an insulating base whose outer peripheral surface has a substantially circular cross-section, and a plurality of commutator pieces arranged on the outer peripheral surface of the insulating base with a gap therebetween in the circumferential direction,
The commutator piece has an arc portion and a terminal portion,
The arc portion has an outer peripheral surface with which the brush is in sliding contact and an inner peripheral surface in contact with the outer peripheral surface of the insulating base,
The insulating base has a concave groove at a position corresponding to the gap,
In the concave groove, a protrusion is provided standing from the inner side to the outer side in the radial direction,
The protrusion is formed along the gap in a non-contact state with the commutator piece,
The commutator is characterized in that the tip of the protrusion is radially inward from the outer peripheral surface of the arc portion.   The commutator according to claim 1, wherein a tip of the protrusion is formed radially inward from an outer peripheral surface of the insulating base.   The commutator according to claim 1, wherein a tip of the protrusion is formed radially outward from an outer peripheral surface of the insulating base. In a commutator comprising an insulating base whose outer peripheral surface is circular in cross section, and a plurality of commutator pieces arranged on the outer peripheral surface of the insulating base with a gap therebetween in the circumferential direction,
The commutator piece has an arc portion and a terminal portion,
The arc portion has an outer peripheral surface with which the brush is in sliding contact and an inner peripheral surface in contact with the outer peripheral surface of the insulating base,
The insulating base is provided with a protruding portion that extends radially outward from the outer peripheral surface,
The protrusion is formed along the gap in a non-contact state with the commutator piece,
The commutator is characterized in that the tip of the protrusion is radially inward from the outer peripheral surface of the arc portion. In a commutator comprising a substantially flat insulating base, and a plurality of commutator pieces arranged on one side of the insulating base with a gap therebetween in the circumferential direction,
The commutator piece has a contact portion with which the brush is in sliding contact, and a terminal portion,
The insulating base has a concave groove at a position corresponding to the gap,
The concave groove is formed with a protrusion standing from the inside to the outside,
The protrusion is formed along the gap in a non-contact state with the commutator piece,
The tip of the protrusion is on the inner side of the outer surface of the contact portion.   The commutator according to claim 5, wherein a tip of the protrusion is formed on an inner side than an outer surface of the one surface.   The commutator according to claim 5, wherein a tip of the protrusion is formed outside an outer surface of the one surface. In a commutator comprising a flat insulating base, and a plurality of commutator pieces arranged on one side of the insulating base with a gap therebetween in the circumferential direction,
The commutator piece has a contact portion with which the brush is in sliding contact, and a terminal portion,
A protrusion is formed on one side of the insulating base,
The protrusion is formed along the gap in a non-contact state with the commutator piece,
The tip of the protrusion is on the inner side of the outer surface of the contact portion.   The commutator according to any one of claims 1 to 8, wherein a tip of the protrusion is in a position not in contact with the brush that is in sliding contact with the adjacent commutator pieces at the same time.   The commutator according to claim 1, wherein the protrusion is formed continuously along the gap.   The commutator according to any one of claims 1 to 10, wherein the protrusion is erected at the center in the circumferential direction of the gap.   The motor with a brush provided with the said commutator of any one of Claims 1 thru | or 11.

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