JP2002204552A - Dc motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve durability against friction of a slidably contacting portion between each brush and a contact electrode formed of a conductive film pattern of a commutator in a DC motor, which assures superior workability in an assembling process, mass-productivity and downsizing by reducing the size in the thrust direction of a part as a whole. SOLUTION: An electrode brush 16 is fixed at a base end portion to a thrust receiving cover 13 with the end part thereof placed under an adequate pressure so as to slidably contact with a contact electrode 23a forming a commutator of a printed circuit board 23. The electrode brush 16 is composed of a pair of electrode brushes placed in contact with each other at a rotating angle which differs in rotating positions by 180 degrees. Each of the pair of electrode brushes 16 is fixed to a rotating shaft 21 on the printed circuit board 23 at the center portion of which the rotating shaft 21 vertically crosses, in a manner such that each of the electrode brushes 16 slidably contacts with each other displacing the position of the radius of the contact electrode 23a of a commutator of the printed circuit board 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brush type DC motor, and more particularly to a DC motor suitable for a small motor used for precision equipment such as a camera.

[0002]

2. Description of the Related Art In a brush type DC motor, a rotor on which a rotor coil is wound is fixed to a rotating shaft, and a magnetic field is applied to the rotor by a stator via a magnetic pole facing the magnetic pole of the rotor. At the same time, power is supplied to the rotor while switching by the electrode brushes and commutators as the rotor rotates. The commutator is configured by contact electrode portions connected to the rotor coil and provided integrally with the rotation shaft and divided into a plurality of portions in the rotation direction, and drive power is supplied from a drive DC power supply to the contact electrode portions. Is supplied to the electrode brush that is in sliding contact with the electrode brush. That is, the DC power applied to the electrode brush is switched and supplied to the rotor coil by switching the contact electrode portion of the commutator in sliding contact.

In general, a commutator in a DC motor of this type has a substantially cylindrical shape, and a plurality of contact electrode portions divided at predetermined rotation angles in a circumferential direction are arranged on an outer peripheral surface.
It is configured to be coaxially fixed to the rotating shaft. Each contact electrode section is connected to a rotor coil. A pair of electrode brushes connected to a driving DC power supply are fixed to the stator side, and slidably contact the contact electrode portions of the commutator at, for example, 180 ° different rotation angle positions. As described above, this type of conventional brush-type DC motor has a contact electrode portion on the outer peripheral surface of a cylindrical commutator fixed coaxially to a rotating shaft.
A type in which a pair of electrode brushes are in sliding contact with each other while being pressed in a substantially radial direction from the outside toward the axis of the cylinder, that is, the axis of the rotary shaft (for example, Utility Model Registration No. 25)
No. 45302).

[0004]

As described above, the direct current motor of the type in which the electrode brush abuts on the outer peripheral surface of the commutator while pressing the outer peripheral surface of the commutator in the direction toward the axis of the rotating shaft is used in manufacturing and assembling. There is a difficulty in workability in assembling the commutator and the electrode brush. That is, the electrode brush is assembled in a state in which a pressing force is applied in a direction from the contact surface of the commutator toward the center, while the commutator is assembled in a direction along the rotation axis. Both are likely to interfere. Especially, in order to prevent the electrode brush from being displaced in the rotation axis direction during operation and falling off from the outer peripheral surface of the commutator, large diameter flanges are provided on both ends of the commutator. Often form a part,
This part increases the complexity of the assembly. Japanese Patent Application Laid-Open No. 6-153456 discloses a commutator having a truncated conical shape, a contact electrode portion formed on a tapered surface, a reduction in a dimension in a thrust direction along a rotation axis of the entire motor, and a complicated assembling operation. Is shown which can reduce the following. But,
In the configuration disclosed in Japanese Patent Application Laid-Open No. 6-153456, the commutator is formed into a truncated conical shape, which complicates the configuration. A special configuration is also required for connecting the contact electrode portion of the commutator to the rotor coil. Required, and the number of components increases.

On the other hand, the present applicant discloses that the rotor coil is mounted on a substantially flat electrical board where the rotation axis intersects perpendicularly with the rotation shaft on which the rotor on which the rotor coil is wound is fixed. A commutator formed by forming a contact electrode portion with a planar conductive film pattern connected to the rectifier is fixed, and a pair of electrode brushes is slid in contact with the planar electrode surface of the contact electrode portion of the commutator. Patent Document 2000 discloses a DC motor provided so that power is supplied to the commutator, or a DC motor further provided so that at least one rotation detecting brush is slidably in contact with a planar electrode surface of the contact electrode portion of the commutator. No. 174571. Using such a configuration, with a small number of parts, good workability during assembly, excellent mass productivity, and downsizing by reducing the overall size in the thrust direction are possible. It is considered that rotation can be detected. However, in the case of such a configuration, a sliding contact portion between the contact electrode portion formed of a planar conductive film pattern of the commutator and each brush is located between a rotating shaft serving as a rotation center and a contact portion of the brush. Sliding contact is performed at a relative speed corresponding to the distance, that is, the radius of the contact point. Therefore, it becomes necessary to consider the wear of the contact electrode portion formed of the conductive film pattern of the commutator.

The present invention has been made in view of the above-mentioned circumstances, and has good workability in assembling, excellent mass productivity,
In addition, in a DC motor that can be downsized by reducing the overall size in the thrust direction, a DC motor that can improve the durability against abrasion of a sliding contact portion between each brush and a contact electrode portion formed of a conductive film pattern of a commutator. It is intended to provide. An object of claim 1 of the present invention is to provide a DC motor capable of effectively improving the durability of the contact electrode portion of the commutator when a pair of electrode brushes is provided. . The object of claim 2 of the present invention can particularly effectively improve the durability of the contact electrode portion of the commutator when a pair of electrode brushes and at least one rotation detection brush are provided. A DC motor is provided.

[0007]

According to a first aspect of the present invention, there is provided a DC motor according to the present invention, wherein the rotor is fixed to a rotating shaft and has a rotor coil wound thereon. A stator that applies a magnetic field to the rotor via a magnetic pole facing the magnetic pole of the rotor, and is fixed to the rotating shaft;
On a substantially flat electrical board where the rotation axis intersects vertically,
A commutator formed by forming a contact electrode portion with a planar conductive film pattern connected to the rotor coil, and a distance from the rotation axis to a planar electrode surface of the contact electrode portion of the commutator. Are provided with a pair of electrode brushes for supplying power by sliding contact at different points, and abutment portions between the pair of electrode brushes and the contact electrode portions of the commutator are radially displaced from each other. It is characterized by.

According to a second aspect of the present invention, there is provided a DC motor according to the present invention, wherein: a rotor fixed to a rotating shaft and having a rotor coil wound thereon; A stator that applies a magnetic field to the rotor via a magnetic pole facing the magnetic pole, and a stator that is fixed to the rotating shaft and connected to the rotor coil on a substantially flat electrical board where the rotating shaft intersects perpendicularly; A commutator having a contact electrode portion formed by a planar conductive film pattern, and a flat electrode surface of the contact electrode portion of the commutator slidingly contacted at points different in distance from the rotation axis. At least one brush which includes a pair of electrode brushes for supplying power and a planar electrode surface of the contact electrode portion of the commutator and which is in contact with another brush including each of the electrode brushes at a point different in distance from the rotation axis. Rotation detection brushes It is characterized in that contact portion between the contact electrode part of the commutator and each of the brushes comprising said brush pair of electrodes and the rotation detecting brush is shifted in the radial direction, respectively.

[0009]

The DC motor according to the first aspect of the present invention applies a magnetic field from the stator to the rotor through a magnetic pole fixed to the rotary shaft and facing the magnetic pole of the rotor on which the rotor coil is wound. A contact electrode portion is formed by a planar conductive film pattern connected to the rotor coil and rectified on a substantially flat electric board fixed to the rotating shaft and perpendicularly intersecting the rotating shaft. And a pair of electrode brushes for supplying power to the planar electrode surface of the contact electrode portion of the commutator are slidably contacted at different points from the rotation axis, respectively. The contact portions of the respective commutators and the contact electrode portions are configured to be shifted from each other in the radial direction. With such a configuration, workability at the time of assembling is good, excellent in mass productivity,
Moreover, in a DC motor that can be downsized by reducing the overall size in the thrust direction, the sliding contact portion between each brush and the contact electrode portion formed of the conductive film pattern of the commutator is different for each brush, When the electrode brush is provided, the durability of the contact electrode portion of the commutator is effectively improved.

According to a second aspect of the present invention, there is provided a DC motor, wherein a magnetic field is applied to the rotor from the stator via a magnetic pole opposed to the magnetic pole of the rotor on which the rotor coil is wound. A contact electrode portion is formed by a planar conductive film pattern connected to the rotor coil and rectified on a substantially flat electric board fixed to the rotating shaft and perpendicularly intersecting the rotating shaft. And a pair of electrode brushes for supplying power to the planar electrode surface of the contact electrode portion of the commutator are configured to be in sliding contact with each other at different points from the rotation axis. A configuration in which at least one rotation detection brush that extracts a rotation detection signal from the planar electrode surface of the contact electrode portion slides in contact with another brush including the electrode brush at a point different in distance from the rotation axis. As Configured to contact portions of said contact electrode portions of the commutator and each of the brushes comprising said brush pair of electrodes and the rotation detecting brush is positioned shifted in the radial direction. With such a configuration, in particular, when the pair of electrode brushes and the at least one rotation detection brush are provided, the durability of the contact electrode portion of the commutator is effectively improved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a DC motor according to the present invention will be described in detail with reference to the drawings. 1 and 2 show a configuration of a DC motor according to a first embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a DC motor, and FIG. 2 is a transverse sectional view of the DC motor showing a detailed configuration of a feed portion, that is, a commutator and a brush for an electrode. 1 and 2 includes a case 11, a stator 12, a thrust receiving cover 13, an upper bearing 14, a lower bearing 15, an electrode brush 16, a rotating shaft 21, a rotor 22, and a printed wiring board 23. I have it. Case 11, stator 12, thrust receiving lid 1
3, upper bearing 14, lower bearing 15, and electrode brush 1
Reference numeral 6 denotes a configuration on the stator side, which does not rotate. Rotary axis 2
1, the rotator 22, and the printed wiring board 23 have a configuration on the rotator side, are integrated with the rotating shaft 21, and rotate together with the rotator 22. In addition, the brush 16 for electrodes is
The pair of first and second electrode brushes 16A and 16B is configured as a pair of electrode brushes.

The rotor 22 includes a rotor coil 22a.
And a rotor core 22b. The printed wiring board 23 is made of, for example, a conductive film pattern formed of a conductive foil. In this case, the contact electrode portion 23a is divided into three equal portions at an angle interval slightly smaller than 120 ° and has a fan shape, and is considerably larger than the contact electrode portion 23a. It has a fan-shaped extension 23b exhibiting a narrow angle. The case 11 has a substantially cylindrical shape or a substantially elliptical cylindrical shape, and the stator 12 is fixed to the inner peripheral surface. The stator 12 is formed, for example, by dividing a cylindrical permanent magnet into two parts, and is magnetized on the inner peripheral surface to form a predetermined number of magnetic poles. Assuming that the cylindrical axial direction of the case 11 is oriented in the vertical direction, the thrust receiving lid 13 forms a bottom surface by closing the lower end opening of the cylindrical case 11. The upper bearing 14 is provided at the upper end opening of the cylindrical case 11 and rotatably supports the rotating shaft 21 through the rotating shaft 21. The lower bearing 15 is fitted and held in a recess formed at the center of the thrust receiving lid 13 and rotatably supports the lower end of the rotating shaft 21. First electrode brush 16A and second electrode brush 16A
In this case, the electrode brush 16 composed of the electrode brush 16B is fixed to the thrust receiving lid 13 at the base end, and the tip end is appropriately set to the contact electrode portion 23a constituting the commutator of the printed wiring board 23. Sliding contact with pressure.

The electric power of the driving power supply is supplied to the rotor coil 22 a of the rotor 22 via the electrode brush 16. The electrode brush 16 is attached to the contact electrode portion 23a constituting the commutator on the printed wiring board 23 by, for example, 180
The first electrode brush 16A and the second electrode brush 16B are in contact with each other at different rotation angle positions. In this case, as shown in the figure, the first electrode brush 16A has a portion near the distal end branched into two, and each branch 16
Between Aa and 16Ab, a slit having a width larger than each of these widths is formed. The branch portions 16Aa and 16Ab of the first electrode brush 16A are respectively provided with a contact electrode portion 23a which is a commutator on the printed wiring board 23.
, At a position at a predetermined distance from the center of the rotating shaft 21, that is, at a predetermined radius position. Contact electrode portion 2 of branching portions 16Aa and 16Ab of first electrode brush 16A
The sliding contact position with respect to 3a is separated by the slit. Similarly, the second electrode brush 16B also has branch portions 16Ba and 16Bb formed by branching the vicinity of the tip into two, and has a width substantially equal to the branch portions 16Aa and 16Ab, respectively. I have. A slit having a width equal to or greater than the width of each of the branch portions 16Ba and 16Bb is formed.

The branch portion 16B of the second electrode brush 16B
a and 16Bb deviate from the contact electrode portion 23a, which is a commutator on the printed wiring board 23, by approximately the width of each of the branch portions 16Ba and 16Bb from the branch portions 16Aa and 16Ab of the first electrode brush 16A. Thus, they are in sliding contact with each other at a position at a predetermined distance from the center of the rotating shaft 21, that is, at a predetermined radius position. Also in this case, the sliding positions of the branch portions 16Ba and 16Bb of the first electrode brush 16B with respect to the contact electrode portion 23a are separated by the slit. Therefore, these four branch portions 16Aa, 16A
b, 16Ba and 16Bb are arranged so as not to overlap with the contact electrode portion 23a.

The rotating shaft 21 is rotatably supported by the case 11 by an upper bearing 14 and a lower bearing 15 disposed at the upper and lower ends of the case 11, and the movement in the thrust direction along the shaft is also preset. Within a predetermined range. In the rotor 22, a rotor coil 22a is wound around a rotor core 22b fixed to the rotating shaft 21.
The printed wiring board 23 is fixed to the rotating shaft 21 so that the rotating disk 21 is substantially disk-shaped or at least one surface is flat, and the rotating shaft 21 vertically intersects at the center. The printed wiring board 23 has, on one surface thereof, three contact electrode portions 23a each having a substantially sector shape by dividing a wide ring-shaped conductive foil portion into three equal parts by, for example, a gap along a radial direction. . The contact electrode portion 23a is guided to the peripheral portion of the printed wiring board 23 by the extension portion 23b, and is appropriately connected to the rotor coil 22a (for example, on the back surface side of a through hole provided in the extension portion). . This printed wiring board 2
3 is formed by applying a plating technique and a printing technique such as forming a conductive foil on at least one surface of the insulating substrate, removing only a required portion of the conductive foil, and removing other portions by etching. Needless to say.

With such a configuration, the commutator is substantially formed by the contact electrode portion 23a formed on one surface of the flat printed wiring board 23, and the electrode brush 16 is formed.
Presses the surface of the contact electrode portion 23a in the axial direction of the rotating shaft 21 to make sliding contact. For this reason, at the time of assembling, the printed wiring board 23 and the thrust receiving lid 13 that supports the electrode brush 16 may be sequentially assembled along the axial direction.
No interference during assembly. Moreover, the printed wiring board 2
Numeral 3 is a flat plate, and the size of the entire motor in the direction along the rotation shaft 21 can be effectively reduced. The commutator is arranged on a flat plate, which is a flat electric board, for example, a printed wiring board 23, and a pair of electrode brushes 16A and 16B are brought into contact with one surface thereof on the same plane. It is simple and does not impair reliability after assembly. In addition, the number of parts can be reduced, and the manufacturing process can be reduced in man-hour and unit cost. Moreover, since the commutator is formed on the same plane, the electrode brushes 16 and the printed wiring board 23 serving as a commutator are arranged in a direction along the axis of the rotating shaft 21, and a cylindrical commutator is formed as in the related art. The size of the motor in the axial direction is shorter than that used, and the size of the motor can be reduced.

Further, as described above, the electrode brush 1
The first electrode brush 16A that forms the first part 6 is branched into branches 16Aa and 16Ab in the vicinity of the tip, and a slit having a width equal to or greater than each of the branches is formed between the branches. Are in sliding contact with the contact electrode portion 23a at a predetermined radial position from the center of the rotating shaft 21 with the slit width therebetween.
The second electrode brush 16B also has a branch portion 16A near the tip.
a and branch 1 having a width substantially equal to 16Ab
6Ba and 16Bb, and a slit having a width equal to or greater than the width of each of them is formed therebetween. These branch portions 16Ba and 16Bb are respectively provided with the first electrode brush 16A with respect to the contact electrode portion 23a. Are in sliding contact with the branch portions 16Aa and 16Ab at a predetermined radial position shifted from the center of the rotating shaft 21 by about the width of each of the branch portions 16Ba and 16Bb, separated by the slit width. Therefore, the radial positions of all the sliding contact portions of the branch portions 16Aa and 16Ab of the electrode brush 16A and the branch portions 16Ba and 16Bb of the electrode brush 16B with respect to the contact electrode portion 23a are shifted from each other.

For this reason, the branch portions 16Aa, 16Ab, the branch portions 16Ba and 16Bb with respect to the contact electrode portion 23a.
Are not overlapped, the wear of the contact electrode portion 23a is remarkably reduced, and the durability of the contact electrode portion 23a is improved. Here, a printed wiring board 23 was used as an electric board, and a commutator was formed by a conductive film formed by plating or the like. Thus, the cost can be reduced by using the printed wiring board 23. However, the present invention is not limited to the printed wiring board 23 as long as the same effect can be obtained, and another electric board may be used. The above corresponds to claim 1. As shown in FIG. 3, a ring-shaped printed resistor 24 for preventing, absorbing and removing noise generated in, for example, a brush portion is provided on the outer peripheral edge of the printed wiring board 23 in the DC motor described above. Extension 23b
What is necessary is just to arrange coaxially so that it may pass above. In this way, the printed resistor 24 on the ring for noise removal is
Since it is provided integrally and fixed to the outer peripheral edge of the printed wiring board 23, it is possible to effectively reduce noise, expand the degree of freedom of space, and reduce costs during manufacturing.

Further, the conductive foil portion other than the contact electrode portion 23a of the printed wiring board 23 may be covered with, for example, a resist to prevent inadvertent conduction. 4 and 5 show a configuration of a DC motor according to a second embodiment of the present invention. FIG. 4 is a longitudinal sectional view of the DC motor, and FIG. 5 is a transverse sectional view of the DC motor showing a detailed configuration of a feed part, that is, a commutator and a brush part. The DC motor shown in FIGS. 4 and 5 is different from the DC motor shown in FIGS. 1 and 2 in that not only the brush for the electrode but also a rotation for detecting the rotation state of the rotor is used as a brush that comes into sliding contact with the commutator. 2 shows a configuration of a DC motor provided with a detection brush 17. 4 and 5
In the figure, the parts corresponding to those in FIGS. 1 and 2 are denoted by the same reference numerals.

That is, the DC motor shown in FIGS. 4 and 5 has a case 11, a stator 12, a thrust receiving cover 13,
It includes an upper bearing 14, a lower bearing 15, an electrode brush 16, a rotation detecting brush 17, a rotating shaft 21, a rotor 22, and a printed wiring board 23. Electrode brush 16
Are configured as a pair of electrode brushes including a pair of first electrode brushes 16A and second electrode brushes 16B. In this case, the rotation detecting brush 17 is
A pair of first rotation detection brushes 17A and second rotation detection brushes 17B is configured as a pair of rotation detection brushes. At least one rotation detection brush 17 may be provided, and three or more rotation detection brushes may be provided if necessary. Further, the rotor 22 has a rotor coil 22a and a rotor core 22b. Printed wiring board 2
Numeral 3 has a contact electrode portion 23a and an extension portion 23b each formed of a conductive film pattern formed of a conductive foil, for example.

The case 11 has a substantially cylindrical shape or an elliptical cylindrical shape in which two semicircular arcs are connected at a predetermined distance from each other as shown in FIG. 5, and a stator 12 is fixed to the inner peripheral surface. I have. The stator 12 is made of, for example, a cylindrical permanent magnet divided into two parts, and is magnetized on the inner peripheral surface to form a predetermined number (two in this case) of magnetic poles. Assuming that the cylindrical axial direction of the case 11 is oriented in the vertical direction, the thrust receiving lid 13 forms a bottom surface by closing the lower end opening of the cylindrical case 11. The upper bearing 14 is provided at the upper end opening of the cylindrical case 11 and rotatably supports the rotating shaft 21 through the rotating shaft 21. The lower bearing 15 is fitted and held in a recess formed at the center of the thrust receiving lid 13 and rotatably supports the lower end of the rotating shaft 21. In this case, the electrode brush 16 including the first electrode brush 16A and the second electrode brush 16B is fixed to the thrust receiving cover 13 at the base end, and the commutator of the printed wiring board 23 at the front end. Is in sliding contact with an appropriate pressure. The electric power of the driving power supply is supplied to the rotor coil 22 a of the rotor 22 via the electrode brush 16. The electrode brush 16 includes a printed wiring board 23.
The contact electrode portion 23a constituting the upper commutator has, for example, 1
The first electrode brush 16A and the second electrode brush 16B are in contact with each other at rotation angle positions different by 80 °.

In this case, the first electrode brush 16A is
As shown, the vicinity of the distal end is branched into two, and a slit having a width equal to or greater than the width of each branch is formed between each of the branch portions 16Aa and 16Ab. The branch portions 16Aa and 16Ab of the first electrode brush 16A are in sliding contact with the contact electrode portion 23a, which is a commutator, on the printed wiring board 23 at a position at a predetermined distance from the center of the rotating shaft 21, that is, at a predetermined radial position. ing. The sliding positions of the branch portions 16Aa and 16Ab of the first electrode brush 16A with the contact electrode portion 23a are separated by the slit. Similarly, the second electrode brush 16B also has a bifurcated portion near the tip divided into two portions.
6Bb are formed, and branch portions 16Aa and 16Aa are respectively formed.
It has a width substantially equal to 6Ab. Each branch 16
Between Ba and 16Bb, a slit having a width larger than each of these widths is formed. The branch portions 16Ba and 16Bb of the second electrode brush 16B are each provided with a contact electrode portion 23 which is a commutator on the printed wiring board 23.
a, the branch portion 16A of the first electrode brush 16A
a and 16Ab are shifted from each other by a width of each of the branch portions 16Ba and 16Bb at a position at a predetermined distance from the center of the rotary shaft 21, that is, at a predetermined radius position. Also in this case, the sliding positions of the branch portions 16Ba and 16Bb of the first electrode brush 16B with respect to the contact electrode portion 23a are separated by the slit.

A rotation detecting brush 17 comprising a first rotation detecting brush 17A and a second rotation detecting brush 17B
Similarly to the electrode brush 16, in this case, the contact electrode portion 23 which is fixed to the thrust receiving cover 13 at the base end and the commutator of the printed wiring board 23 is formed at the tip end.
a is in sliding contact with a suitable pressure. Via this rotation detecting brush 17, potential fluctuations due to the rotation of the motor in the contact electrode portion 23a, which is a commutator on the printed wiring board 23, are detected and output as a rotation signal from the thrust receiving lid 13 to the outside. The rotation detecting brush 17 is provided with a contact electrode portion 23 a that constitutes a commutator on the printed circuit board 23.
For example, the first rotation detection brush 17A and the second rotation detection brush 17B that are in contact with each other at rotation angle positions different by 180 ° are provided. These first rotation detection brush 17A and second rotation detection brush 17B
First electrode brush 16A and second electrode brush 16B
, For example, at a rotational angle position shifted by 40 °.

In this case, the first rotation detecting brush 17A
As shown in the figure, the vicinity of the tip is branched into two, and a slit having a width equal to or greater than the width of each of them is formed between the branch portions 17Aa and 17Ab. Branches 17Aa and 17A of first rotation detecting brush 17A
b denotes a position at a predetermined distance longer than the outermost edge of the sliding portion of the electrode brush 16 from the center of the rotating shaft 21 with respect to the contact electrode portion 23a which is a commutator on the printed wiring board 23, that is, the electrode brush. The sliding contact is made at a predetermined radius position outside the 16 sliding contact portions. First rotation detection brush 1
Contact electrode part 23 of branch part 17Aa and 17Ab of 7A
The sliding position with respect to a is separated by the slit. Similarly, the second rotation detecting brush 17B also
The vicinity of the distal end is branched into two, branching portions 17Ba and 17B
b are formed, and branch portions 17Aa and 17A
has a width substantially equal to b. Each branch part 17Ba
A slit having a width equal to or greater than the width of each of them is formed between and 17Bb.

Branch 1 of second rotation detecting brush 17B
7Ba and 17Bb are printed circuit boards 2 respectively.
The first rotation detecting brush 17A is separated from the contact portions 23Ba and 17Bb of the first rotation detecting brush 17A outside the sliding contact portion of the electrode brush 16 with respect to the contact electrode portion 23a, which is a commutator on the third. They are in sliding contact with each other at a position at a predetermined distance from the center of the rotating shaft 21, that is, at a predetermined radius position, shifted by about each width. Also in this case, the sliding contact positions of the branch portions 17Ba and 17Bb of the first rotation detecting brush 17B with the contact electrode portion 23a are separated by the slit. The rotating shaft 21 is formed by the upper bearing 14 and the lower bearing 15 disposed at the upper and lower ends of the case 11.
1 and is also rotatably supported, and movement in the thrust direction along the axis is also restricted within a predetermined range set in advance. In the rotor 22, a rotor coil 22a is wound around a rotor core 22b fixed to the rotating shaft 21. The printed wiring board 23 has a substantially disk shape, and is fixed to the rotating shaft 21 such that the rotating shaft 21 intersects vertically at the center. The printed wiring board 23 has, on one surface, a wide ring-shaped conductive foil portion divided into three equal parts by, for example, a gap along the radial direction, and each of the contact electrode portions 2 has a substantially fan shape.
3a is formed.

The contact electrode portion 23a is guided by the extension portion 23b to the periphery of the printed wiring board 23, and is appropriately connected to the rotor coil 22a as described above.
With such a configuration, the commutator is substantially formed by the contact electrode portion 23a formed on one surface of the flat printed wiring board 23, and the electrode brush 16 and the rotation detecting brush 17 are The surface of the contact electrode portion 23a is pressed in the axial direction of the rotating shaft 21 to make sliding contact. For this reason, at the time of assembling, the thrust receiving cover 1 that supports the printed wiring board 23, the electrode brush 16 and the rotation detecting brush 17 is provided.
3 may be sequentially assembled along the axial direction, and there is no interference at the time of assembly. Moreover, the printed wiring board 23 has a flat plate shape, and the size of the entire motor in the direction along the rotating shaft 21 can be effectively reduced. The commutator is disposed on a flat plate, which is a flat electrical board, for example, a printed wiring board 23, and has a pair of electrode brushes 16A and 16B and rotation detection brushes 17A and 17 on one surface.
Since B contacts on the same plane, assembling is simple, and the reliability after assembling is not impaired.

Further, the number of parts can be reduced, and the cost can be reduced both in terms of man-hours in the manufacturing process and in terms of unit price. In addition, since the commutator is formed on the same plane, the electrode brush 16 and the rotation detecting brush 17 and the printed wiring board 23 as the commutator are arranged in the direction along the axis of the rotating shaft 21 as in the conventional case. The size of the motor in the axial direction is shorter than when a cylindrical commutator is used, and the size of the motor can be reduced. Further, as described above, the first electrode brush 16A constituting the electrode brush 16
Is divided into branch portions 16Aa and 16Ab in the vicinity of the tip, and a slit having a width equal to or greater than the width of each of the branch portions is formed between the branch portions 16Aa and 16Ab.
b is in sliding contact with the contact electrode portion 23a at a predetermined radial position from the center of the rotary shaft 21 with a distance of the slit width. The second electrode brush 16B also has branch portions 16Aa and 16Ab near the tip. Branches 16Ba and 16Bb having substantially the same width are formed, and a slit having a width equal to or greater than the respective width is formed between them. These branch portions 16Ba and 16Bb are respectively connected to the contact electrode portion 23a. The branch portions 16Aa and 16Ab of the first electrode brush 16A are
At a predetermined radius position which is shifted from the center of 1 by about the width of each of the branch portions 16Ba and 16Bb, they are in sliding contact with each other at the slit width. Therefore, the branch portions 16Aa and 16A of the electrode brush 16A with respect to the contact electrode portion 23a.
b, and the radial positions of all the sliding portions of the branch portions 16Ba and 16Bb of the electrode brush 16B are shifted from each other. The first rotation detecting brush 17A constituting the rotation detecting brush 17 has a branch portion 17 near its tip.
Aa and 17Ab are branched, and a slit having a width larger than each of these widths is formed between these. , The second rotation detecting brush 17B also has a branch portion 17Ba having a width substantially equal to the width of the branch portions 17Aa and 17Ab near the tip thereof.
And 17Bb, and a slit having a width larger than the width of each of them is formed therebetween. These branch portions 17Ba and 17Bb are respectively connected to the contact electrode portions 23B and 17Bb.
a of the first rotation detecting brush 17A
7Aa and 17Ab are in sliding contact with each other at a predetermined radial position deviated from the center of the rotating shaft 21 by about the width of each of the branch portions 17Ba and 17Bb with the slit width therebetween. Therefore, the branch portions 17Aa and 17Ab of the rotation detecting brush 17A with respect to the contact electrode portion 23a, and the branch portions 17Ba and 17B of the rotation detecting brush 17B.
The radial positions of all the sliding contact portions b are shifted from each other. Further, the first and second electrode brushes 16 constituting the electrode brushes 16 with respect to the contact electrode portion 23a.
The distance from the center of the rotating shaft 21 of the sliding contact portions of A and 16B to the distance from the center of the rotating shaft 21 of the first and second rotation detecting brushes 17A and 17B constituting the rotation detecting brush 17 constituting the rotation detecting brush 17. The distance is different. Therefore, the branch portions 16Aa and 16Ab of the electrode brush 16A and the electrode brush 16B
Branches 16Ba and 16Bb of the Rotation Detection Brush 1
Radial positions of all the sliding contact portions of the branch portions 17Aa and 17Ab of the 7A and the branch portions 17Ba and 17Bb of the rotation detecting brush 17B are shifted from each other as shown by a virtual dashed line in FIG. Become. Therefore, the branch portion 16A of each brush with respect to the contact electrode portion 23a
a, 16Ab, 16Ba, 16Bb, 17Aa, 17A
The sliding contact portions of b, 17Ba and 17Bb do not overlap, wear of the contact electrode portion 23a is remarkably reduced, and durability of the contact electrode portion 23a is improved.

Here, the case where the printed wiring board 23 is used as the electrical board and the commutator is formed by a conductive film formed by photo-etching or vapor deposition processing is described. Cost reduction can be achieved by using it.
However, the present invention is not limited to the printed wiring board 23 as long as the same effect can be obtained, and another electric board may be used. The above corresponds to claim 2. Also in this case, as shown in FIG. 3, a ring-shaped printed resistor 24 for preventing, absorbing, and removing noise generated in, for example, a brush portion is provided on the outer peripheral edge of the printed wiring board 23 in the DC motor described above. They may be arranged coaxially.
In this way, the printed resistor 24 on the ring for removing noise is connected to the extended portion 2 on the outer peripheral edge of the printed circuit board 23.
Since it is fixed and integrally provided so as to be stacked on the 3b, effective noise reduction can be achieved, and the degree of freedom of space can be increased and the cost during manufacturing can be reduced.

Further, the conductive foil portion other than the contact electrode portion 23a of the printed wiring board 23 may be covered with, for example, a resist or the like to prevent inadvertent conduction. When the electrode brush and the rotation detecting brush are provided, in a state as shown in FIG. 6, the electrode brush B1 is connected to the commutator CM.
In contact with the two conductor pieces on the upper left and upper right
Rotation detection brush D (in this case, one brush will be described)
Is in contact with two conductor pieces on the upper right and lower side of the commutator CM in the figure, and the electrode brush B2 is in contact with the conductor piece on the lower side of the commutator CM in the figure. Therefore, the electrode brush B1 connected to the positive side of the power source E is connected to the negative conductor of the power source E via the upper right conductor piece of the commutator CM, the rotation detecting brush D, and the lower conductor piece of the commutator CM. It is electrically connected to the electrode brush B2 connected to the side. Therefore, as a result,
The positive and negative ends of the power supply E are short-circuited.

The existence of such a state does not often cause a serious problem when the DC motor is rotating at a high speed, but becomes a problem when the motor stops in this state. Generally, the rotor of this type of DC motor is configured by winding a coil around an iron core, and when no current flows through the coil, the iron core is attracted to a magnetic pole of a stator made of a permanent magnet. For example, in the case of a three-pole motor, there are six stable points. If the position corresponding to the stable point is removed and the position of the rotation detecting brush D in sliding contact with the commutator CM is set, the above-described problem is reduced, but the short-circuit state of the power supply E does not occur. Is desirable. In order to prevent such a short-circuit state of the power supply E from occurring, the sliding contact position of the rotation detecting brush D with the commutator CM should be between the sliding contact position of the electrode brush B2 in the case of a three-pole motor. May be less than 60 °. That is, in the case of a motor having n poles (n is a natural number of 3 or more), the angle between the electrode brush B2 and the sliding contact position may be less than 180 / n °. FIG. 5 shows the rotation detecting brush 17 according to the present invention in accordance with the above considerations.
A and 17B are replaced with a pair of electrode brushes 16A and 1B.
It is arranged at an angle position of 40 ° with respect to 6B. By doing so, a short circuit state of the power supply E does not occur at all. Therefore, the reliability of the rotation detection signal and the operation of the motor can be improved.

[0031]

As described above, according to the present invention, there is provided a DC motor which has good workability at the time of assembling, is excellent in mass productivity, and which can be downsized by reducing the overall size in the thrust direction. Further, it is possible to provide a DC motor capable of improving durability against abrasion of a sliding contact portion between each brush and a contact electrode portion formed of a commutator conductive film pattern. That is, according to the DC motor of claim 1 of the present invention, a magnetic field is applied from the stator to the rotor via the magnetic pole fixed to the rotary shaft and facing the magnetic pole of the rotor on which the rotor coil is wound. And forming a contact electrode portion on a substantially flat electrical board fixed to the rotating shaft and intersecting the rotating shaft at right angles by a planar conductive film pattern connected to the rotor coil. A pair of electrode brushes for supplying power to the planar electrode surface of the contact electrode portion of the commutator,
Each of the pair of electrode brushes and the contact portion of the commutator with the contact electrode portion are radially displaced from each other in a configuration in which the respective contact portions of the pair of electrode brushes and the commutator contact each other in a radial direction. With this configuration, the DC motors have good workability during assembly, are excellent in mass productivity, and can be downsized by reducing the overall size in the thrust direction. The sliding contact portion with the contact electrode portion is made different for each brush, and in particular, the durability of the contact electrode portion of the commutator when a pair of electrode brushes is provided is effectively improved.

According to the DC motor of the second aspect of the present invention, the rotor is fixed to the rotating shaft via the magnetic pole facing the magnetic pole of the rotor on which the rotor coil is wound. While applying a magnetic field, a contact electrode portion is formed by a planar conductive film pattern connected to the rotor coil on a substantially flat electrical board fixed to the rotation axis and intersecting the rotation axis vertically. A commutator, and a pair of electrode brushes for supplying power to the planar electrode surface of the contact electrode portion of the commutator are configured to be in sliding contact with each other at different radial distances from the rotation axis, At least one rotation detection brush that extracts a rotation detection signal from the planar electrode surface of the contact electrode portion of the commutator has a different distance from the rotation axis than other brushes including the brushes for the electrodes. Sliding at a point As a configuration, each of the brushes including the pair of electrode brushes and the rotation detection brush and the contact portion of the commutator with the contact electrode portion are configured so as to be shifted in the radial direction. In particular, the durability of the contact electrode portion of the commutator is effectively improved when a pair of electrode brushes and at least one rotation detection brush are provided.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a DC motor according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a configuration of a sliding contact portion between a commutator and an electrode brush of the DC motor of FIG.

FIG. 3 is a cross-sectional view for explaining a detailed configuration of a commutator portion of the DC motor of FIG. 1;

FIG. 4 is a vertical sectional view of a DC motor according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a configuration of a sliding portion of a commutator and an electrode brush of the DC motor of FIG. 4;

FIG. 6 is a schematic diagram for explaining a conventional problem in an electrode brush, a rotation detection brush, and a commutator of a DC motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Case 12 Stator 13 Thrust receiving lid 14 Upper bearing 15 Lower bearing 16, 16A, 16B Electrode brush 17, 17A, 17B Rotation detecting brush 21 Rotating shaft 22 Rotor 22a Rotor coil 22b Rotor core 23 Printed wiring board 23a Contact electrode part (commutator) 23b Extension part 24 Print resistance

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenji Koyama 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. (reference) 5H613 AA01 AA02 BB04 BB07 BB16 BB19 BB35 GA04 GA10 GB01 PP02 PP05 5H623 AA00 BB07 GG13 GG16 HH04 JJ01 JJ05

Claims (2)

[Claims] A rotor fixed to a rotating shaft and wound with a rotor coil; a stator for applying a magnetic field to the rotor via a magnetic pole facing the magnetic pole of the rotor; A commutator comprising a contact electrode portion formed by a planar conductive film pattern connected to the rotor coil on a substantially flat electrical board on which the rotation axis intersects perpendicularly; A pair of electrode brushes for supplying power by slidingly contacting the planar electrode surface of the contact electrode portion at a point different in distance from the rotation axis, and rectifying each of the pair of electrode brushes with the rectifier. A direct-current motor, wherein the contact portions of the contacts with the contact electrode portions are shifted in the radial direction. 2. A rotor fixed to a rotating shaft and having a rotor coil wound thereon, a stator for applying a magnetic field to the rotor via a magnetic pole facing a magnetic pole of the rotor, and a rotating shaft. A commutator comprising a contact electrode portion formed by a planar conductive film pattern connected to the rotor coil on a substantially flat electrical board on which the rotation axis intersects perpendicularly; A pair of electrode brushes for supplying power by sliding contact with the planar electrode surface of the contact electrode portion at points having different distances from the rotation axis, and a planar electrode surface of the contact electrode portion of the commutator. And at least one rotation detection brush slidably in contact with another brush including the electrode brush at a point different in distance from the rotation axis, wherein the pair of electrode brushes and the rotation detection brush are provided. Each of the brushes including A direct-current motor, wherein the contact portions of the flow element with the contact electrode portion are shifted in the radial direction.