JP2002262536A - Dc machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a DC machine which can remove a fault in rectification with a third brush and also can reduce the number of components and costs. SOLUTION: A magnet 2 is provided with a soft-steel structure part 16 which is composed of a material having permeability larger than that of the magnet 2. This soft-steel structure part 16 is provided at an area where when the third brush 8 short-circuit both segments 12a, 12b provided adjacently, in a state that an armature 4 is fed from a first brush 6 and a second brush 7 and rotated, the end part in the rotating direction of a tooth bar of a first tooth 10a in the rotational direction of five teeth 10a, to which an armature coil 11 wired to both segments 12a, 12b is wound, reaches the structure part 16. Moreover, the soft-steel structure part 16 is formed in the width corresponding to an angle θ1 in the rotational direction, which is a period for the third brush 8 to short- circuit the both segments 12a, 12b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC machine having a magnet.

[0002]

2. Description of the Related Art Conventionally, a DC motor having a brush has been employed as an automobile wiper motor. In this,
There is a three-brush motor, a motor using a so-called third brush. In this type of motor, a third brush is used for the purpose of changing the rotation speed of the motor. The main principle is to increase the rotation speed of the motor by reducing the magnetic flux used. Specifically, it has been easily realized by providing brushes having different installation positions and changing the energization range of the armature coil by selecting (combining) the brushes.

[0003]

By the way, in the above configuration, in normal operation of the motor (low-speed specification), every time a high-speed brush (third brush) straddles an adjacent commutator piece,
Due to the induced electromotive force generated in the armature coil short-circuited by the brush (third brush), a large current instantaneously flows in a direction opposite to the current application direction. In FIG. 12, peaks A2 and B2 indicate instantaneous changes in coil current flowing in the armature coil. As a result, a spark discharge occurs in the brush, which causes electrical noise and brush wear, and causes so-called rectification failure by the third brush. Therefore, a plurality of coils (inductors), capacitors, and the like for preventing noise were combined in the motor drive circuit. This is a problem in reducing the number of parts and cost of the motor.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to change the magnetic flux distribution of a magnet so as to eliminate a so-called rectification obstacle caused by a third brush. Another object of the present invention is to provide a DC machine capable of reducing costs.

[0005]

In order to solve the above-mentioned problems, the invention according to claim 1 is provided by winding an armature coil around an armature core having a plurality of teeth provided at equal angular intervals. An armature, an armature coil of which is connected to a commutator, a pair of magnets arranged to face each other with the armature interposed therebetween, and arranged at a position facing a center axis of the armature, to contact a segment of the commutator. In a DC machine comprising: first and second brushes, and at least one third brush arranged at a predetermined angle from an opposing position of the first and second brushes and in contact with the segment, One of the pair of magnets is provided with a constituent part made of a material having a higher magnetic permeability than the magnet, and the constituent part is such that the armature is composed of the first brush and the second brush. When the third brush starts short-circuiting both segments adjacent to each other in a state in which the armature coil is connected to both segments in a state in which the armature coil is wound around the first segment in the rotation direction of the plurality of teeth wound around the two segments. The tooth brush is provided at a position where the tip in the rotational direction comes to approach the component, and the third brush is formed with a width corresponding to the rotational direction angle during which the two segments are short-circuited. Make a summary.

According to a second aspect of the present invention, there is provided an armature in which an armature coil is wound around an armature core having a plurality of teeth provided at equal angular intervals, and the armature coil is connected to a commutator. A pair of magnets disposed opposite to each other across the armature, a first and a second brush disposed at a position facing the central axis of the armature and in contact with a segment of the commutator; And a brush arranged at a predetermined angle from an opposing position of the first brush and at least one third brush contacting the segment, wherein one of the pair of magnets is transparent to the other magnet. A constituent part made of a material having a high magnetic susceptibility is provided, and the constituent part is such that the armature is the first part
With the brush and the second brush feeding and rotating,
When the third brush starts short-circuiting the adjacent segments, the rear end of the teeth bar in the rotation direction of the first tooth opposite to the rotation direction of the plurality of teeth on which the armature coils connected to the two segments are wound is opposite. The gist is that the third brush is formed at a position corresponding to the rotation direction angle, which is a period in which both segments are short-circuited.

[0007] The invention described in claim 3 is the first or second invention.
In the DC machine described in the above, the component is formed over the whole so as to be parallel to the central axis of the armature by embedding a material having a high magnetic permeability in a gap formed between the divided pieces that divide the magnet. The gist is that it is done.

The invention described in claim 4 is the first or second invention.
In the direct current machine described in the above, the gist is such that the component is formed so as to embed a material having high magnetic permeability in a notch formed by notching the magnet.

[0009] The invention according to claim 5 is the invention according to claims 1 to 4.
In the DC machine according to any one of the above,
The gist is that it is made of mild steel. (Operation) According to the first to fifth aspects of the present invention, the change in the magnetic flux is reduced at the moment when the third brush short-circuits the adjacent segments, so that the magnetic flux is generated in the armature coil as compared with the related art. The induced electromotive force is suppressed, and a sharp reverse current change does not occur.

According to the third aspect of the invention, since the magnetic flux is reduced over the entire width of the magnet, the effect of reducing the electric noise and brush wear of the DC machine is further enhanced.

According to the fourth aspect of the present invention, the structure is simple, and the material can be easily manufactured while making the material portion clear. According to the fifth aspect of the present invention, since the components are formed of mild steel, the rigidity of the entire magnet can be ensured, and the magnet can be easily manufactured.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) An embodiment in which the present invention is embodied in a DC motor (for example, a wiper motor) as a DC machine will be described with reference to the drawings. Figure 1
FIG. 1 is a partial cross-sectional view illustrating a schematic structure of a wiper motor 1 of the present embodiment.

As shown in FIG. 1, the wiper motor 1 has magnets 2 and 3, an armature 4, a commutator 5, and a plurality of brushes 6 to 8. More specifically, the wiper motor 1 of the present embodiment is a two-pole DC motor, and two magnets 2 and 3 forming an N pole and an S pole are opposed to each other across an armature 4 in a motor housing yoke 9. Are located. The armature 4 includes an armature core 10 and its core 1
And an armature coil 11 wound around the motor, and is driven to rotate by supplying a direct current.

The armature core 10 includes a plurality of teeth 10
a are formed, of which n teeth 10a
, An armature coil 11 is wound therearound. In the present embodiment, the number of the teeth 10a is 12, and the number of the teeth 10a is 30 in the circumferential direction of the armature 4.
It is formed every °. In other words, adjacent teeth 10
a is the angle formed by the center line (motor armature slot angle)
θ is 30 ° (= 360 ° / 12). Although not shown, a plurality of armature coils 11 are similarly wound around the five teeth 10a. That is, the winding method of the winding is distributed winding.

The commutator 5 is provided at one end of the armature 4 and has a plurality of segments 12.
In the present embodiment, twelve segments 12 are 3 in the circumferential direction.
It is provided every 0 °. As shown in FIG. 1, the armature coil 11 wound around the five teeth 10a is
It is connected to two segments 12 (for example, segments 12a and 12b) on the side substantially opposite to one tooth 10a.

Further, the plurality of brushes 6 to 8 are arranged in a state of being urged so as to slide on the commutator 5. In the present embodiment, three brushes 6 to 8 are provided. Among them, as shown in FIG. 1, the first and second brushes 6 and 7 as the first and second brushes are disposed in a 180 ° apart (opposing) relationship, and serve as a third brush. The third brush 8 is disposed so as to form a predetermined angle δ with the first brush 6. In the present embodiment, the angle δ is the first
The angle is set to be an acute angle from the brush 6 in the rotation direction. Further, the brushes 6 to 8 have respective terminals 6a.
Through 8a to the DC power supply circuit 13.

More specifically, the DC power supply circuit 13 includes a DC power supply 14 and a changeover switch 15, and the brushes 6, 8
Are the terminals 6a and 8a and the changeover switch 15 respectively.
The second brush 7 is connected to the minus electrode of the DC power supply 14 via the terminal 7a. That is, the changeover switch 15 is switched depending on the operation state to supply power to the motor 1 via the brushes 6 and 7 or the motor 1
To be supplied with power.

In this embodiment, the changeover switch 15 is switched to supply power to the motor 1 through the brushes 6 and 7 during normal operation (low-speed specification), and the motor 1 through brushes 7 and 8 during high-speed operation. The changeover switch 15 is switched so as to supply power to the power supply. That is, the brushes 6 and 7 are arranged at the first position where the rotation speed is low, and the brushes 7 and 8 are arranged at the second position where the rotation speed is high.

The switching of the switch 15 causes the DC current supplied from the DC power supply 14 to flow to the armature coil 11 via the brushes 6 and 7 or the brushes 7 and 8 and the segment 12 of the commutator 5. by this,
The armature 4 rotates clockwise (in the figure, in the direction of the arrow X).

The magnets 2 and 3 have a predetermined length (for example, as shown in FIG. 1, the motor armature slot angle θ).
Are formed so as to be point-symmetrical to each other with respect to the central axis of the armature 4 at an opening angle (length corresponding to 4θ = 120 °) which is an integral multiple of.

As shown in FIGS. 1 and 2, the magnet 2 is provided with a mild steel component 16 as a component made of a material having a higher magnetic permeability than the magnet 2 at a predetermined position. In the present embodiment, the magnet 2 has two divided pieces 2.
a, 2b, and a gap 2c is formed between the two divided pieces 2a, 2b. The mild steel component 16 is formed so that mild steel as a material having a higher magnetic permeability than the magnet 2 is embedded in the gap 2c. That is, as shown in FIG. 2, the mild steel component 16 is formed integrally with the two divided pieces 2a and 2b so as to be parallel to the central axis of the armature 4.

The mild steel component 16 is provided at a predetermined location near the end of the magnet 2 in the rotation direction.
As shown in FIG. 1, when the third brush 8 starts short-circuiting the segments 12a and 12b during rotation of the armature 4, the armature coil 11 connected to the segments 12a and 12b is located at the predetermined location. Five teeth 1 to be wound
The first tooth 10 a in the rotation direction 0 a is set at a position where the tip of the tooth bar in the rotation direction of the first tooth 10 a comes to reach the mild steel component 16. Also, as shown in FIG.
The mild steel component 16 includes a third brush 8 in which both segments 12
a and 12b are formed with a width corresponding to the rotation direction angle θ1 during which the short circuit occurs.

FIG. 3 shows a state in which power is supplied to the brushes 6 and 7 (normal operation).
2 shows a change in the current flowing through the armature coil 11 connected to both the segments 12 when the short circuit 2 is performed. In the present embodiment, as shown in FIG. 1, when the armature 4 rotates clockwise in a state where power is supplied by the brushes 6 and 7 (normal operation), the third brush 8 short-circuits both adjacent segments 12. At the start of the rotation, the tips of the first teeth 10a in the rotation direction of the five teeth 10a around which the armature coils 11 connected to the two segments 12 are wound are approaching the mild steel component 16. In other words, during normal operation, the first teeth 10a on the rotation direction side of the five teeth 10a around which the armature coil 11 is wound.
When the tip of the tooth bar in the rotation direction of the toothed bar approaches the mild steel component 16, both segments 12 to which the armature coil 11 is connected start to be short-circuited by the third brush 8. In the normal operation of the motor 1 supplied with power by the brushes 6 and 7, the third
When the brush 8 short-circuits the adjacent segments 12a and 12b, the tooth 10a around which the armature coil 11 connected to the segments 12a and 12b is wound reaches the mild steel component 16 having high magnetic permeability. In comparison, the induced electromotive force generated in the armature coil 11 is suppressed. As a result, as shown in FIG.
The peak current A1 and the peak B1
However, a sharp reverse current change unlike the related art does not occur.

As described above, the present embodiment has the following features. (1) The magnet 2 was provided with a mild steel component 16 made of a material having a higher magnetic permeability than the magnet 2. When the third brush 8 starts short-circuiting the adjacent segments 12a and 12b in a state where the armature 4 is rotated by being supplied with power by the first brush 6 and the second brush 7, the mild steel component 16 The five teeth 10a around which the armature coils 11 connected to 12a and 12b are wound are provided at locations where the tips of the first teeth 10a in the rotation direction of the teeth 10a in the rotation direction of the teeth 10a come into contact with the component 16. . Further, the component 16 includes a rotation direction angle θ1 during which the third brush 8 short-circuits the segments 12a and 12b.
Is formed in a width corresponding to

Therefore, since the change in magnetic flux is reduced at the moment when the third brush 8 short-circuits the adjacent segments 12, the induced electromotive force generated in the armature coil 11 is suppressed as compared with the related art, and the opposite direction is obtained. No drastic current change occurs.

As a result, spark discharge in the third brush 8 is prevented, and electric noise of the motor 1 and brush wear can be reduced. This eliminates the need to combine a plurality of coils (inductors), capacitors, and the like for preventing noise in the drive circuit of the motor 1, thereby reducing the number of parts and cost of the motor 1.

(2) Since the magnet 2 is provided with the mild steel component 16 having a high magnetic permeability, it is possible to reduce the commutation failure caused by the third brush, and therefore it is easy to manufacture and advantageous in cost.

(3) Since the mild steel component 16 is formed so as to be parallel to the central axis of the armature 4, the effect of reducing the electric noise of the motor 1 and the brush abrasion is greater. Become.

(4) The mild steel component 16 is made of mild steel. Therefore, the rigidity of the entire magnet 2 can be secured, and the manufacture of the magnet 2 is easy. (Second Embodiment) Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a partial cross-sectional view illustrating a schematic structure of the DC motor 21 of the present embodiment.

As shown in FIG. 4, the DC motor 21 has magnets 22, 23, an armature 24, a commutator 25, and a plurality of brushes 26-28. To elaborate,
The DC motor 21 of the present embodiment is a two-pole DC motor in which two magnets 22 and 23 forming an N-pole and an S-pole are opposed to each other across an armature 24 in a motor housing yoke 29. I have. The armature 24 includes an armature core 30 and an armature coil 3 wound around the core 30.
1 and is driven to rotate by supplying a DC current.

The armature core 30 includes a plurality of teeth 30
a are formed, of which n teeth 30a
, An armature coil 31 is wound therearound. In the present embodiment, the number of the teeth 30a is 12, and the number of the teeth 30a is three in the circumferential direction of the armature 24.
It is formed every 0 °. In other words, adjacent teeth 3
0a is formed such that an angle (motor armature slot angle) θ formed by the center line thereof is 30 ° (= 360 ° / 12). Although not shown, a plurality of armature coils 31 are similarly wound around the five teeth 30a. That is, the winding method of the winding is distributed winding.

The commutator 25 is provided at one end of the armature 24 and has a plurality of segments 32. In the present embodiment, twelve segments 32 are provided every 30 ° in the circumferential direction. As shown in FIG. 4, the armature coil 31 wound around the five teeth 30a is connected to two segments 32 (for example, the segments 32a and 32b) on the five teeth 30a side.

The plurality of brushes 26 to 28 are disposed in a state of being urged so as to slide on the commutator 25. In the present embodiment, three brushes 26 to 28 are provided. Among them, as shown in FIG. 4, first and second brushes 26 and 27 as first and second brushes are provided.
Are disposed in a 180 ° apart (opposing) relationship, and the third
The third brush 28 is disposed so as to form a predetermined angle δ1 with the second brush 27. further,
Although not shown, the brushes 26 to 28 are connected to a DC power supply circuit via respective terminals.

The magnets 22 and 23 have a predetermined length (for example, as shown in FIG. 4, a length corresponding to an opening angle (5θ = 150 °) which is an integral multiple of the motor armature slot angle θ). They are formed so as to be point-symmetric with respect to the central axis of the armature 24.

As shown in FIG. 4, the magnet 22 includes
A mild steel component 36 is provided as a component made of a material having a higher magnetic permeability than the magnet 22. In the present embodiment, the magnet 22 includes two divided pieces 22a and 22b.
And a gap 22 is formed between the divided pieces 22a and 22b.
c is formed. The mild steel component 36 is formed so that mild steel as a material having a higher magnetic permeability than the magnet 22 is embedded in the gap 22c. That is, the mild steel component 36 is formed integrally with the two split pieces 22a and 22b so as to be parallel to the central axis of the armature 24.

The mild steel component 36 is provided at a predetermined position near the end of the magnet 22 in the rotation direction. When the third brush 28 starts short-circuiting the two segments 32a and 32b during rotation of the armature 24, the predetermined locations include five teeth around which the armature coils 31 connected to the two segments 32a and 32b are wound. The first tooth 30a in the rotation direction of the rotation direction 30a is set at a position where the tip of the tooth bar in the rotation direction of the tooth 30a comes to reach the mild steel component 36. The mild steel component 36 has a width corresponding to an angle θ1 in the rotation direction during which the third brush 28 short-circuits the two segments 32a and 32b.

FIG. 5 shows that the armature 24 has A (0
The change of the induced voltage generated in the armature coil 31 during the rotation from the (°) position to the B (180 °) position is shown.
In the present embodiment, during normal operation, when the tips of the five teeth 30a around which the armature coils 31 are wound around the first teeth 30a in the rotation direction of the five teeth 30a approach the mild steel constituent part 36, the electric motor The two segments 32 to which the child coils 31 are connected start to be short-circuited by the third brush 28. That is, the armature 24 is rotated by approximately 90 ° while rotating from the position A (0 °) to the position B (180 °) shown in FIG.
a, 32b begins to short circuit. Correspondingly, as shown in FIG. 5, when the armature 24 rotates about 90 ° while rotating from the position A (0 °) to the position B (180 °) shown in FIG. The induced voltage generated in the inside becomes almost zero.

As described above, according to the present embodiment, substantially the same effects as those of the first embodiment can be obtained. (Third Embodiment) Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. FIG. 6 is a partial sectional view showing a schematic structure of the DC motor 41 of the present embodiment. Note that the present embodiment differs from the second embodiment in that a magnet provided with a mild steel component is different. Therefore, for the sake of convenience, detailed description of the configuration of the same DC motor is omitted, and Only the parts that do are described in detail.

As shown in FIG. 6, the magnet 43 located on the opposite side of the rotation direction of the brush 48 from the third brush 48 as the third brush is made of a material having a higher magnetic permeability than the magnet 43. Mild steel component 5 as component
6 are provided. In the present embodiment, the magnet 43
Is divided into two divided pieces 43a and 43b, and a gap 43c is formed between the two divided pieces 43a and 43b. The mild steel component 56 is provided with a magnet 43 in the gap 43c.
It is formed so as to embed mild steel as a material having higher magnetic permeability. That is, the mild steel component 56 is
Are formed integrally with the two divided pieces 43a and 43b so as to be parallel to the central axis of.

The mild steel component 56 is provided at a predetermined location near the end of the magnet 43 in the rotation direction. This predetermined location is where the third brush 48 is
When the two segments 52a, 52b start short-circuiting during the rotation of the tooth, the teeth bar of the first tooth 50a on the opposite side of the rotation direction of the five teeth 50a around which the armature coil 51 connected to the both segments 52a, 52b is wound. It is set at a position where the rear end in the rotation direction reaches the mild steel component 56. The mild steel component 56 has a width corresponding to an angle θ1 in the rotation direction during which the third brush 48 short-circuits the segments 52a and 52b.

FIG. 7 shows that the armature 44 has A (0
The change in the induced voltage generated in the armature coil 51 during the rotation from the (°) position to the B (180 °) position is shown.
In the present embodiment, in the normal operation of the motor 41 supplied with power by the brushes 46 and 47, both segments 52a and 52b
When the rear ends in the rotation direction of the first teeth 50a of the first teeth 50a on the opposite side of the rotation direction of the five teeth 50a around which the armature coils 51 connected to the armature coil 51 are wound approach the mild steel component 56, the third brushes 48 Segments 52a, 5
Start shorting 2b. That is, the armature 44 short-circuits the two segments 52a and 52b adjacent to each other with the third brush 48 at a position rotated by about 90 ° while rotating from the position A (0 °) to the position B (180 °) shown in FIG. start. Correspondingly, as shown in FIG. 7, the armature 44 has the A (0
°) position to rotate to B (180 °) position
When rotated, the induced voltage generated in the armature coil 51 becomes substantially zero.

Therefore, according to this embodiment, substantially the same effects as those of the first and second embodiments can be obtained.
Each of the above embodiments may be implemented in the following manner.

In each of the above-described embodiments, as shown in FIG. 8, the structure is formed by embedding a mild steel material in a notch 62b formed by cutting the side surface 62a of the magnet 62. May be. Further, as shown in FIG. 9, the present invention may be embodied in a component portion 76 formed so that a mild steel material is embedded in a through hole 72 a as a cutout portion formed through the magnet 72. Further, as shown in FIGS. 10 and 11, the present invention may be implemented by a component part 86 formed by embedding a mild steel material in a notch part 82 a formed by notching the inner surface of the magnet 82. In these cases, substantially the same effects as those of the above embodiments can be obtained, and the production can be easily performed while the material distribution is clear.

In the first embodiment, the third brush 8
Are arranged so as to form an acute angle on the rotation direction side with the first brush 6, and the mild steel component 16 is provided at a position near the rotation direction side end of the magnet 2. On the other hand, the third brush 8 is arranged so as to form an obtuse angle on the rotation direction side with the first brush 6, and the mild steel component 16 is provided at a position close to the end of the magnet 2 on the anti-rotation direction side. Is also good. Although not shown, the third brush 8 may be arranged so as to form an obtuse angle or an obtuse angle on the anti-rotational direction side with the first brush 6, and a component having a high magnetic permeability may be provided on the magnet 3. In this case, the same effect as in the first embodiment can be obtained.
Note that the second and third embodiments may be modified based on the same concept.

The components 16, 36, 56, 66, 76,
86 may be formed of a material having a high magnetic permeability other than mild steel. The magnet of the first embodiment may be formed with a length other than the length corresponding to the opening angle (4θ = 120 °) which is an integral multiple of the motor armature slot angle θ. The magnets of the second and third embodiments may be formed with a length other than the length corresponding to the opening angle (5θ = 150 °) which is an integral multiple of the motor armature slot angle θ.

[0063] A plurality of third brushes may be provided. The present invention may be embodied in a motor provided with a plurality of teeth other than 12 and implemented. The same armature coil may be wound around n teeth other than five.

In the first embodiment, the DC machine is embodied in the wiper motor 1, but the DC machine may be embodied in another motor other than the wiper motor 1. Next, technical ideas that can be grasped from the above embodiments and other examples will be additionally described below.

(1) An armature coil is wound around an armature core having a plurality of teeth provided at equal angular intervals, and the armature coil is connected to a commutator, and is opposed to the armature with the armature interposed therebetween. A pair of magnets, a first and a second brush arranged at a position facing the central axis of the armature and in contact with a segment of the commutator, and a pair of the first and second brushes from the facing position of the first and the second brushes. In a wiper motor including at least one third brush arranged at a predetermined angle and in contact with the segment, one of the pair of magnets includes:
A constituent part made of a material having a higher magnetic permeability than the magnet is provided, and the constituent part is arranged such that the third brush is adjacent to the armature while the armature is rotated by being supplied with power by the first brush and the second brush. A place where when a short circuit is started between both matching segments, the first end of the teeth in the rotation direction of the teeth in the rotation direction of the plurality of teeth around which the armature coils connected to the two segments are wound approaches the component. And a third brush having a width corresponding to a rotation direction angle during which the two segments are short-circuited.

Therefore, the commutation obstacle caused by the third brush can be eliminated, and the number of parts and cost of the wiper motor can be reduced.

[0050]

As described in detail above, according to the present invention,
The commutation failure due to the third brush can be eliminated, and the number of parts and cost of the DC machine can be reduced.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view illustrating a schematic configuration of a DC motor according to a first embodiment.

FIG. 2 is a perspective view of a magnet provided with a mild steel structure according to the first embodiment.

FIG. 3 is a graph showing a change in a coil current flowing in the armature coil according to the first embodiment;

FIG. 4 is a partial cross-sectional view illustrating a schematic configuration of a DC motor according to a second embodiment.

FIG. 5 is a graph showing a change in an induced voltage generated in an armature coil according to the second embodiment.

FIG. 6 is a partial cross-sectional view illustrating a schematic configuration of a DC motor according to a third embodiment.

FIG. 7 is a graph showing a change in an induced voltage generated in an armature coil according to a third embodiment.

FIG. 8 is a perspective view of a magnet provided with another example of a mild steel structure.

FIG. 9 is a perspective view of a magnet provided with another example of a mild steel structure.

FIG. 10 is a partial cross-sectional view showing a schematic configuration of another example of a DC motor.

FIG. 11 is a perspective view of a magnet provided with another example of a mild steel structure.

FIG. 12 is a graph showing a change in coil current flowing in a conventional armature coil.

[Explanation of symbols]

1,1,41 ... DC motors as DC machines, 2,3
22, 23, 42, 43, 62, 72, 82 ... magnet, 2a, 2b, 22a, 22b, 43a, 43b ... divided pieces constituting a magnet, 2c, 22c, 43c ... between both divided pieces constituting a magnet Gap, 4, 24, 44
... armature, 5, 25, 45 ... commutator, 6, 26,
46... The first brush as the first brush, 7, 27, 4
7. Second brush as second brush, 8, 28, 48
... the third brush as the third brush, 10, 30, 50
... armature core, 10a, 30a, 50a ... teeth, 1
1, 31, 51 ... armature coil, 12, 32, 52 ... segment, 16, 36, 56, 66, 76, 86 to 23
... Components made of a material having high magnetic permeability, 62b, 72
a, 82a: Notch.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H613 AA07 BB15 BB35 GA11 QQ01 TT01 5H623 AA03 BB07 GG13 GG16 GG22 JJ01 LL13

Claims (5)

[Claims] An armature coil is wound around an armature core having a plurality of teeth provided at equal angular intervals. The armature coil is connected to a commutator and is opposed to the armature with the armature interposed therebetween. A pair of magnets, first and second brushes arranged at positions facing the center axis of the armature and in contact with the segments of the commutator, and a predetermined distance from the facing positions of the first and second brushes. A DC machine comprising: at least one third brush that is arranged at an angle and contacts the segment; wherein one of the pair of magnets is made of a material having a higher magnetic permeability than the magnet. A third part of the armature, wherein the armature is rotated by being supplied with power by the first brush and the second brush, and the third brush is adjacent to both segments. When short-circuiting begins, the armature coil connected to both segments is provided at a position where the tip of the first tooth in the rotation direction of the plurality of teeth wound around the teeth bar in the rotation direction of the first teeth comes to approach the component. And a third brush having a width corresponding to an angle in the rotation direction during which the two segments are short-circuited. 2. An armature coil wound around an armature core having a plurality of teeth provided at equal angular intervals, said armature coil being opposed to an armature connected to a commutator with said armature interposed therebetween. A pair of magnets, first and second brushes arranged at positions facing the center axis of the armature and in contact with the segments of the commutator, and a predetermined distance from the facing positions of the first and second brushes. A DC machine comprising: at least one third brush that is arranged at an angle and contacts the segment; wherein one of the pair of magnets is made of a material having a higher magnetic permeability than the magnet. A third part of the armature, wherein the armature is rotated by being supplied with power by the first brush and the second brush, and the third brush is adjacent to both segments. When short-circuiting begins, a plurality of teeth around which the armature coils connected to the two segments are wound are provided at locations where the rear ends of the first teeth in the rotation direction of the teeth opposite to the rotation direction of the first teeth come close to the component. And a third brush formed with a width corresponding to an angle in the rotational direction during which the two segments are short-circuited. 3. The DC machine according to claim 1, wherein the component is configured such that a material having high magnetic permeability is embedded in a gap formed between the divided pieces that divide the magnet, and the center axis of the armature is formed. A direct current machine characterized by being formed over the whole so as to be parallel. 4. The DC machine according to claim 1, wherein the component is formed such that a material having high magnetic permeability is embedded in a notch formed by cutting the magnet. A DC machine characterized by that: 5. The DC machine according to claim 1, wherein the component is made of mild steel.