JP2011142760A - Direct current rotary electric machine - Google Patents

Abstract

An inner rotor type DC rotating electrical machine capable of preventing contact failure more appropriately.
A DC rotating electric machine 1 according to the present invention includes a rotor 2, a stator 4 including an armature 3 disposed on the outer peripheral side of the rotor 2, and a plurality of terminals of a winding 6 constituting the armature 3. A commutator 7 perpendicular to the axial direction of the rotor 2 to be connected, a positive slip ring 8 and a negative slip ring 9 that form a peripheral surface perpendicular to the radial direction of the rotor 2, and a first contact surface 10 a that contacts the commutator 7. A positive electrode brush 10 including a second contact surface 10b that contacts the positive electrode slip ring 8, a negative electrode brush 11 including a third contact surface 11a that contacts the commutator 7, a fourth contact surface 11b that contacts the negative electrode slip ring 9, and a rotor 2 and includes a holder 12 that holds the positive electrode brush 10 and the negative electrode brush 11. The distance D 1 from the central axis C of the rotor 2 of the first contact surface 10 a and the third contact surface 11. Wherein the distance D2 is equal from the center axis C of the.
[Selection] Figure 1

Description

  The present invention relates to a DC rotating electric machine having a brush and a commutator, and relates to a so-called inner rotor type DC rotating electric machine in which an armature is arranged outside a rotor.

  In a DC rotating electric machine including a brush and a commutator (commutator), for example, a configuration in which an armature is disposed inside and a rotor has an armature as described in Patent Document 1, for example, is common. In this case, in order to rotate the magnetic pole generated by the armature based on the relative rotation between the stator and the armature, a DC voltage is supplied to the armature using a brush and a commutator.

  However, as shown in FIG. 3, for example, in recent years, an armature 103 composed of a winding 101 and a core 102 is disposed on the outer peripheral side of the rotor 120 and fixed to the yoke 105 of the stator 104. A configuration including 121 is widely used. This configuration is referred to as an inner rotor type.

  Also in the inner rotor type DC rotating electric machine 100 having such a configuration, the magnetic poles of the armature 103 are rotated based on the relative rotation of the stator 104 and the rotor 120. A shaft 122 of the rotor 120 is rotatably supported with respect to the stator 104 via a bearing 106, and a disc-shaped brush holder 123 is drivingly coupled to the shaft 122. Further, the brush 124 is inserted through an insertion hole oriented in the axial direction of the brush holder 123.

  When the DC voltage is supplied from the brush 124 to the armature 103 via the commutator 130, the brush 124 is always rotated with respect to the stator 104. The brush 124 is connected via a slip ring 108.

  In this way, in the inner rotor type DC rotating electric machine 100, the brush 124 for positive electrode feeding and rectification shown in the lower side of FIG. 3 and the negative electrode feeding and rectification of the upper side in FIG. For each of the brushes 124, two annular slip rings 108 arranged in parallel in the radial direction are provided.

  Further, the two slip rings 108 are supported by the ring holder 109 so as to be movable in the axial direction with respect to the yoke 105, and the ring holder 109 is urged toward the left in FIG. 3 by the brush spring 110.

  Due to the urging force of the brush spring 110, the ring holder 109 is displaced in the axial direction toward the commutator 130, the left end of the brush 124 in FIG. 3 is pressed by the commutator 130, and the right end of the brush 124 in FIG. Is pressed by the slip ring 108.

  Each of the slip rings 108 is connected to each of positive and negative lead wires 107, and the pair of lead wires 107 are pulled out through a through hole provided in the stator 104 on the right side in FIG. A corresponding connecting wire 111 is connected to a plurality of segments of the commutator 130, and each terminal of the corresponding winding 101 is connected to the connecting wire 111.

  In the DC rotating electrical machine 100 shown in FIG. 3 described above, the positive and negative brushes 124 have power feeding and rectifying functions, and the brushes 124 are held on the shaft 122 via the brush holder 123. .

  The radial positions of the pair of brushes 124 are disposed so as not to overlap in the radial direction corresponding to the two slip rings, and the radial positions are different from each other. For this reason, the peripheral speed during rotation differs between the pair of brushes 124. Due to the fact that the amount of wear of the brush 124 is proportional to the peripheral speed, the wear of one of the pair of brushes 124 located on the radially outer side is accelerated and the amount of wear increases, and one of the brushes has poor contact ahead of the other. Cause the problem of causing.

  As a conventional technique for improving this problem, for example, there is a technique as shown in FIG. In FIG. 4, the contact surface of the commutator 130 with respect to the brush 124 is cylindrical, the pair of rectifying brushes 124 are arranged on the same diameter, and the pair of positive and negative slip rings 107 are arranged in the axial direction. ing. A lead wire 108 is connected to each of the positive and negative slip rings 107.

  In addition, a power supply brush 125 connected to the brush 124 via a lead wire is added, and a contact pressure spring 126 that presses the brush 124 radially outward, and a contact pressure spring that presses the brush 125 radially outward. 127 is also added.

  In this way, by arranging the pair of brushes 124 in contact with the commutator 130 on the same circumference, the peripheral speeds of the positive and negative brushes 124 with respect to the commutator 130 are made the same with each other. The difference in the amount of wear is eliminated.

JP-A-8-182259

  However, depending on the configuration shown in FIG. 4, the number of contact springs 126 and 127 increases, the brush 125 itself is added, and the lead wire connecting the brush 124 and the brush 125 is added. Incurs an increase. In other words, it cannot be said that a technique capable of preventing contact failure more appropriately without incurring disadvantages. For this reason, in the prior art, there arises a problem that it is not possible to provide an inner rotor type DC rotating electrical machine that can prevent contact failure more appropriately.

  Therefore, an object of the present invention is to provide an inner rotor type DC rotating electrical machine that can prevent contact failure more appropriately.

In order to solve the above problem, the DC rotating electric machine according to the present invention is:
A stator, and a stator including an armature disposed on an outer peripheral side of the rotor;
A commutator perpendicular to the axial direction of the rotor connected to each of a plurality of terminals of a winding constituting the armature;
A positive slip ring and a negative slip ring that form a circumferential surface perpendicular to the radial direction of the rotor;
A positive electrode brush including a first contact surface in contact with the commutator and a second contact surface in contact with the positive electrode slip ring;
A negative electrode brush including a third contact surface in contact with the commutator and a fourth contact surface in contact with the negative electrode slip ring;
Including a holder that is drivingly coupled to the rotor and holds the positive brush and the negative brush;
The distance from the central axis of the rotor to the first contact surface is equal to the distance from the central axis of the third contact surface.

  According to the DC rotating electric machine of the present invention, the distance from the central axis of the first contact surface that contacts the commutator of the positive electrode brush and the third contact surface of the negative electrode brush that contacts the commutator. Since the distance from the central axis is the same, the peripheral speed of the first contact surface with respect to the commutator accompanying the rotation and the peripheral speed of the third contact surface can be made the same.

  That is, since the peripheral speeds of the first contact surface and the third contact surface are the same, the wear rate can be the same, and wear of one of the positive electrode brush and the negative electrode brush is accelerated compared to the other. It is possible to prevent a situation in which contact failure occurs at an early stage. Thereby, contact stability can be improved.

  In addition, since the positive slip ring and the negative slip ring are arranged in parallel in the axial direction, and the commutator can be a plane perpendicular to the axial direction, it is necessary for power supply and rectification of the DC rotating electric machine. This makes it possible to arrange the proper parts more appropriately. That is, the axial length of the DC rotating electrical machine can be shortened by arranging the positive slip ring, the negative slip ring, and the commutator at right angles to each other. Thereby, size reduction and weight reduction of the DC rotating electrical machine can be achieved.

  Further, the DC rotating electric machine according to the present invention has the commutator, the positive electrode brush, the negative electrode brush, and a slip ring arranged side by side in the axial direction as compared to the DC rotating electric machine of the form shown in FIG. There is no increase in size in the axial direction. Furthermore, the DC rotating electrical machine does not incur an increase in cost and weight due to an increase in the number of parts due to the addition of lead wires or the addition of the number of brushes, compared to the configuration shown in FIG.

  Therefore, the direct current rotating electrical machine of the present invention prevents contact failure without incurring an increase in size, cost, or weight, and thus can prevent contact failure more appropriately without causing disadvantages.

  According to the present invention, it is possible to provide an inner rotor type DC rotating electrical machine that can prevent contact failure more appropriately.

It is a schematic diagram shown in the cross section containing a central axis about one Embodiment of the direct current | flow rotary electric machine which concerns on this invention. It is a schematic diagram which shows the principal part about one Embodiment of the direct current | flow rotary electric machine which concerns on this invention. It is a schematic diagram which shows the conventional DC rotary electric machine. It is a schematic diagram which shows the conventional DC rotary electric machine.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic view showing a DC rotating electrical machine 1 of this embodiment in a cross section including a central axis C of a rotor 2. FIG. 2 is a schematic diagram showing the main part of the DC rotating electric machine 1 of the present embodiment both before and after assembly.

  As shown in FIG. 1, the DC rotating electric machine 1 of this embodiment is wound around a rotor 2, a stator 4 including an armature 3 disposed on the outer peripheral side of the rotor 2, and a core 5 constituting the armature 3. A commutator 7 perpendicular to the axial direction of the rotor 2 connected to each of a plurality of terminals of the winding 6, and a positive slip ring 8 and a negative slip ring 9 that form a circumferential surface perpendicular to the radial direction of the rotor 2. .

  Furthermore, the DC rotating electrical machine 1 of the present embodiment includes a positive electrode brush 10 including a first contact surface 10 a that contacts the commutator 7 and a second contact surface 10 b that contacts the positive electrode slip ring 8, and a third contact that contacts the commutator 7. The first contact surface 10a includes a negative electrode brush 11 including a fourth contact surface 11b that contacts the surface 11a and the negative electrode slip ring 9, and a holder 12 that is drivingly coupled to the rotor 2 and holds the positive electrode brush 10 and the negative electrode brush 11. The distance D1 from the center axis C of the rotor 2 is equal to the distance D2 from the center axis C of the third contact surface 11a.

  Magnets 13 are juxtaposed in the circumferential direction on the outer peripheral surface of the rotor 2. The rotor 2 is drivingly coupled to a shaft 14, and the shaft 14 is supported by a bearing 15 so as to be rotatable with respect to a yoke 16 of the stator 4. A disk-shaped holder 12 is drivingly coupled to the right side of the shaft 14 in FIG.

  On the surface of the holder 12 on the side facing the commutator 7, the positive brush 10 and the negative brush 11 are arranged on the diameter of the holder 12 so as to be located on the opposite sides in the radial direction. A brush spring 17 (contact pressure spring) is interposed between the positive electrode brush 10 and the holder 12, and a brush spring 17 (contact pressure spring) is also interposed between the negative electrode brush 11 and the holder 12.

  Although illustration is omitted, the winding 6 constituting the armature 3 is provided with a plurality of terminals, and the plurality of terminals are respectively connected to the plurality of commutators 7 corresponding to the corresponding commutators 7 via the corresponding connecting wires 18. Segments are connected. These segments are formed by pressing a bus bar made of a conductor such as copper, for example, and forming a fan shape in which a ring is divided on the surface of the commutator 7 facing the holder 12.

  Further, the positive electrode slip ring 8 is disposed on the left side in FIG. 1 relative to the negative electrode slip ring 9, that is, at a position separated in the axial direction from the commutator 7.

  The positive slip ring 8 is connected to a lead wire 19 inserted through an insertion hole formed in the lower radial direction of the yoke 16 in FIG. 1, and the negative slip ring 9 is drilled in the upper radial direction of FIG. It is connected to the lead wire 20 inserted through the inserted hole. The lead wire 19 and the lead wire 20 are accommodated in a connector (not shown), and this connector is connected to a vehicle-side connector. For example, a positive slip ring 8 is connected to a control terminal of a body ECU (Electronic Control Unit) (not shown). The negative slip ring 9 is connected to the ground terminal of the body ECU.

  In the above-described DC rotating electrical machine 1 of the present embodiment, when a DC voltage is applied to the positive slip ring 8 and the negative slip ring 9 from the body ECU, a magnetic field is generated in the core 5 by the winding 6. The magnetic field generated by the core 5 and the magnet 13 of the rotor 2 are attracted and repelled, and the rotor 2 is rotated. As the rotor 2 rotates, the holder 12 fastened to the shaft 14 is also rotated. By this rotation, one segment of the plurality of segments in which the positive electrode slip ring 8 is electrically connected by the positive electrode brush 10 and the other segment in which the negative electrode slip ring 9 is electrically connected by the negative electrode brush 11 and the rotor 2 or The combination of segments located on the opposite side of the commutator 7 in the radial direction is sequentially switched.

  By this sequential switching, the energized winding 6 among the windings 6 of the armature 3 provided in the stator 4 is sequentially switched, and the magnetic field generated by the winding 6 of the armature 3 is also rotated. The magnet 13 of the rotor 2 is continuously attracted and repelled by the magnetic field, and the rotor 2 is continuously rotated.

  In the DC rotating electric machine 1 of the first embodiment, the shapes of the positive electrode brush 10 and the negative electrode brush 11 in the cross section including the central axis C of the rotor 2 are inverted L-shaped. Further, when the brush spring 17 (contact pressure spring) is interposed between the holder 12 and the positive electrode brush 10 and the negative electrode brush 11, the brush spring 17 is a corner portion of the inverted L-shaped positive electrode brush 10 and the negative electrode brush 11. Is inserted into a guide pin 21 having one end embedded therein. The guide pin 21 is embedded so as to be inclined by a set angle φ with respect to the axial sides of the positive electrode brush 10 and the negative electrode brush 11.

  In the DC rotating electrical machine 1 according to the first embodiment, as shown in FIG. 1, the first contact surface 10 a and the second contact are based on the set angle φ formed between the expansion and contraction direction of the brush spring 17 and the axial direction or radial direction. The contact pressures of the surface 10b, the third contact surface 11a, and the fourth contact surface 11b are set.

  Further, in the DC rotating electric machine 1 of the first embodiment, as shown in FIG. 2, the holder 12 includes a pin insertion portion 22 including a hollow cylindrical portion into which a guide pin 21 corresponding to the positive electrode brush 10 is inserted, and a negative electrode brush. 11 includes a pin insertion portion 23 including a hollow cylindrical portion into which a guide pin 21 corresponding to 11 is inserted. The outer peripheral surface of the hollow cylindrical portion of the pin insertion portion 22 holds the brush spring 17 corresponding to the positive brush 10, and the outer peripheral surface of the hollow cylindrical portion of the pin insertion portion 23 holds the brush spring 17 corresponding to the negative electrode brush 11, respectively. Hold.

  In addition, the holder 12 includes a holding wall 24 that holds the positive electrode brush 10 in the circumferential direction of the rotor 2 and a holding wall 25 that holds the negative electrode brush 11 in the circumferential direction of the rotor 2. The pin insertion portion 22 described above is provided at the corner of the holding wall 24 so as to be inclined with respect to the axial direction of the rotor 2 by a set angle φ, and the pin insertion portion 23 is also set at the corner of the holding wall 25 in the axial direction. Inclined by φ.

  Further, in the DC rotating electrical machine 1 according to the first embodiment, the positive electrode slip ring 8 is disposed at a position farther from the commutator 7 than the negative electrode slip ring 9, and the positive electrode brush 10 is disposed in the axial direction parallel to the central axis C. The length is longer than the length of the negative electrode brush 11.

  According to the DC rotating electrical machine 1 of the present embodiment described above, the following operational effects can be obtained. That is, the distance D1 from the central axis C of the first contact surface 10a that contacts the commutator 7 of the positive electrode brush 10 is equal to the distance D2 from the central axis C of the third contact surface 11a that contacts the commutator 7 of the negative electrode brush 11. Therefore, the peripheral speed of the first contact surface 10a with respect to the commutator 7 accompanying the rotation of the rotor 2 and the peripheral speed of the third contact surface 11a can be made equal to each other.

  Thus, by equalizing the peripheral speeds of the first contact surface 10a and the third contact surface 11a, the wear rate of the positive electrode brush 10 on the first contact surface 10a and the wear rate of the negative electrode brush 11 on the third contact surface 11a. Can be made equal to each other. For this reason, it is possible to avoid a situation in which one of the positive electrode brush 10 and the negative electrode brush 11 is significantly accelerated in wear compared with the other and leads to poor contact at an early stage. In this way, contact stability can be improved by preventing one from wearing early and exceeding the wear limit, resulting in poor contact.

  Further, the positive slip ring 8 and the negative slip ring 9 are arranged side by side adjacent to each other in the axial direction of the rotor 2, and the commutator 7 can be a plane perpendicular to the axial direction. Necessary arrangement of parts can be made more appropriate by efficiently using the space in three dimensions.

  That is, the arrangement relationship among the positive electrode brush 10, the negative electrode brush 11, the positive electrode slip ring 8, the negative electrode slip ring 9, and the commutator 7 can be made more appropriate for space saving. In other words, by arranging the positive slip ring 8, the negative slip ring 9 and the commutator 7 at right angles to each other, the space of the DC rotating electrical machine 1 can be effectively used, and these can be simply used in the axial direction or the radial direction. Compared with arrangement, both the axial and radial lengths of the entire device can be reduced. By shortening the length, the DC rotating electrical machine 1 can be reduced in size and weight.

  In addition, in the DC rotating electric machine 1 of the present embodiment, the positive slip ring 8 is connected to the segment of the commutator 7 by the positive brush 10 or the negative slip ring 9 is connected to the segment of the commutator 7 by the negative brush 11. There is no need to add additional lead wires or brushes. That is, it is possible to avoid an increase in cost and an increase in weight due to an increase in the number of parts.

  That is, according to the DC rotating electrical machine 1 of the present embodiment, the contact failure between the commutator 7 and the positive electrode brush 10 or the negative electrode brush 11 is prevented without increasing the size, cost, and weight of the entire apparatus. be able to. For this reason, it can be said that the DC rotating electrical machine 1 which can implement | achieve the more suitable contact failure prevention method which does not cause a demerit, and a prevention method is provided.

  In addition to this, in the DC rotating electrical machine 1 of the present embodiment, the shape of the positive electrode brush 10 and the negative electrode brush 11 in the cross section including the central axis C of the rotor 2 is an inverted L-shape. In addition, advantages in manufacturing and insulation can be obtained.

  That is, the first contact surface 10a and the second contact surface 10b in the positive electrode brush 10 shown in FIGS. 1 and 2 are, for example, the first contact surface 10a and the second contact surface 10b because the commutator 7 and the positive electrode slip ring 8 are perpendicular to each other. In the case of the DC rotating electrical machine 1 of the present embodiment, the inconvenience of an increase in the number of parts and a complicated structure is assumed if it is constituted by independent brushes each having the one contact surface 10a and the second contact surface 10b. By using both ends of the inverted L shape which the positive electrode brush 10 originally has, it can be configured more easily without causing this inconvenience.

  Further, the recesses in the corners between both ends of the inverted L-shape can prevent direct conduction between the commutator 7 and the positive electrode slip ring 8 and enhance the insulation performance. Furthermore, weight reduction of positive electrode brush 10 itself can be achieved from the hollow of a corner part.

  Similarly, the third contact surface 11a and the fourth contact surface 11b of the negative electrode brush 11 shown in FIG. 1 and FIG. 2 are different from each other because the commutator 7 and the negative electrode slip ring 9 are perpendicular to each other. In the case of the DC rotating electrical machine 1 of the present embodiment, if the vertical brush is constituted by independent brushes each having the third contact surface 11a and the fourth contact surface 11b, the number of parts is increased. The brush 11 can be configured more easily by using both ends of the inverted L shape that the brush 11 originally has.

  Further, the recesses at the corners between both ends of the inverted L shape can prevent direct conduction between the commutator 7 and the negative electrode slip ring 9 to enhance the insulation performance. In addition, the weight of the negative electrode brush 11 itself can be reduced from the depression at the corner.

  Further, in the DC rotating electric machine 1 of the present embodiment, since the brush spring 17 is interposed between the holder 12 and the positive electrode brush 10 and the negative electrode brush 11, the positive electrode brush 10 is brushed to the commutator 7 and the positive electrode slip ring 8. Appropriate contact can be made based on the biasing force of the spring 17. Similarly, the negative electrode brush 11 can be appropriately brought into contact with the commutator 7 and the negative electrode slip ring 9 by the urging force of the brush spring 17.

  Furthermore, in the DC rotating electrical machine 1 of the present embodiment, the first contact surface 10a, the second contact surface 10b, the third contact surface 11a, based on the set angle φ formed between the expansion and contraction direction of the brush spring 17 and the axial direction. Each contact pressure of the fourth contact surface 11b can be set.

  For example, if the set angle φ is 45, the contact pressure between the first contact surface 10a and the second contact surface 10b is the same, and the contact pressure between the third contact surface 11a and the fourth contact surface 11b is the same. can do.

  Further, if the set angle φ is shifted in a small direction, the contact pressure of the first contact surface 10a and the third contact surface 11a with respect to the commutator 7 can be set higher based on the same brush spring 17, and conversely, the second contact The contact pressure between the surface 10b and the fourth contact surface 11b can be set low.

  Similarly, if the set angle φ is shifted in the larger direction, the contact pressure of the second contact surface 10 b that contacts the positive electrode slip ring 8 is set higher based on the same brush spring 17 and contacts the negative electrode slip ring 9. The contact pressure of the fourth contact surface 10d can be set higher, and conversely, the contact pressure of the first contact surface 10a and the third contact surface 11a can be set lower.

  As described above, according to the DC rotating electrical machine 1 of the present embodiment, the contact pressure on the first contact surface 10a and the second contact surface 10b of the positive electrode brush 10 can be appropriately set based on the set angle φ. Similarly, the contact pressure on the third contact surface 11a and the fourth contact surface 11b of the negative electrode brush 11 can be appropriately set based on the set angle φ.

  In addition, in the DC rotating electrical machine 1 of the present embodiment, the positive brush 10 and the negative brush 11 include guide pins 21 that define the expansion and contraction direction of the brush spring 17, and the holder 12 is a pin into which the guide pins 21 are inserted. Since the insertion portions 22 and 23 are included and the pin insertion portions 22 and 23 hold the brush spring 17, it is further advantageous in the following points.

  That is, according to the DC rotating electrical machine 1 of the present embodiment, the contact pressure between the commutator 7 and the positive electrode brush 10 and the contact pressure between the positive electrode brush 10 and the positive electrode slip ring 8 can be appropriately adjusted by the set angle φ, The above-described configuration capable of realizing an appropriate contact pressure setting can be realized with a relatively simple configuration using the guide pin 21 and the pin insertion portions 22 and 23.

  Further, in the DC rotating electrical machine 1 of the present embodiment, the holder 12 includes holding walls 24 and 25 that hold the positive electrode brush 10 and the negative electrode brush 11 in the circumferential direction of the rotor 2. 11 can be stabilized in the circumferential direction when the rotor 2 is rotated, and the stability of contact with the commutator 7, the positive electrode slip ring 8, and the negative electrode slip ring 9 can be improved.

  In addition, in the DC rotating electrical machine 1 of the present embodiment, the positive electrode slip ring 8 is positioned with the negative electrode slip ring 9 sandwiched from the commutator 7, and is positioned farther from the commutator 7 than the negative electrode slip ring 9. Therefore, the length of the positive electrode brush 10 can be longer than the length of the negative electrode brush 11 in the axial direction.

  That is, in the DC rotating electrical machine 1 of the present embodiment, the positive brush 10 is generally more than the negative brush 11 after taking this into consideration based on the knowledge that the positive brush 10 generally wears more than the negative brush 11. To increase the wear limit and durability. That is, the length relationship between the positive electrode brush 10 and the negative electrode brush 11 in the axial direction can be made appropriate in advance.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Can do.

  The present invention relates to a direct current rotating electrical machine that is suitable for use in automobile memory seat systems, power window devices, sunroof devices, power steering devices, and the like. According to the present invention, it is possible to provide an inner rotor type DC rotating electrical machine capable of more appropriately preventing contact failure. Therefore, the present invention is applicable to various automobiles and is useful.

DESCRIPTION OF SYMBOLS 1 DC rotary electric machine 2 Rotor 3 Armature 4 Stator 5 Core 6 Winding 7 Commutator 8 Positive electrode slip ring 9 Negative electrode slip ring 10 Positive electrode brush 10a First contact surface 10b Second contact surface 11 Negative electrode brush 11a Third contact surface 11b Fourth Contact surface 12 Holder 13 Magnet 14 Shaft 15 Bearing 16 Yoke 17 Brush spring (contact pressure spring)
18 Crossover wire 19 Lead wire 20 Lead wire φ Setting angle 21 Guide pin 22 Pin insertion portion 23 Pin insertion portion 24 Retaining wall 25 Retaining wall

Claims (8)

  A rotor, a stator including an armature disposed on an outer peripheral side of the rotor, a commutator perpendicular to the axial direction of the rotor, each connected to a plurality of terminals of a winding constituting the armature, and the rotor A positive electrode slip ring and a negative electrode slip ring that form a peripheral surface perpendicular to a radial direction of the positive electrode brush, a positive electrode brush that includes a first contact surface that contacts the commutator, and a second contact surface that contacts the positive electrode slip ring, and contacts the commutator A negative electrode brush including a third contact surface and a fourth contact surface that contacts the negative electrode slip ring, and a holder that is drivingly coupled to the rotor and holds the positive electrode brush and the negative electrode brush. A DC rotating electric machine characterized in that a distance from a central axis of the rotor is equal to a distance from the central axis of the third contact surface.   2. The DC rotating electric machine according to claim 1, wherein a shape of the positive electrode brush and the negative electrode brush in a cross section including a central axis of the rotor is an L shape or an inverted L shape.   The DC rotating electric machine according to claim 2, wherein a contact pressure spring is interposed between the holder, the positive brush, and the negative brush.   Each of the first contact surface, the second contact surface, the third contact surface, and the fourth contact surface is based on a set angle formed by the expansion / contraction direction of the contact pressure spring and the axial direction or the radial direction. 4. The DC rotating electric machine according to claim 3, wherein a contact pressure is set.   The positive electrode brush and the negative electrode brush include a guide pin that defines the expansion / contraction direction, the holder includes a pin insertion portion into which the guide pin is inserted, and the pin insertion portion holds the contact pressure spring. The DC rotating electric machine according to claim 4, wherein:   The DC rotating electric machine according to claim 5, wherein the holder includes a holding wall that holds the positive electrode brush and the negative electrode brush in a circumferential direction of the rotor.   The DC rotating electrical machine according to claim 6, wherein the positive slip ring is disposed at a position farther from the commutator than the negative slip ring.   The DC rotating electric machine according to claim 7, wherein a length of the positive electrode brush is longer than a length of the negative electrode brush in the axial direction.