JP5248087B2 - Electric motor - Google Patents

Description

  The present invention relates to an electric motor that is mounted on an automobile or the like and can be switched in rotation speed.

  In general, many electric motors with brushes are used as electric motors mounted on vehicles such as automobiles. In this type of electric motor, a plurality of permanent magnets are arranged at equal intervals in the circumferential direction on the inner peripheral surface of a cylindrical yoke, and an armature is rotatably supported inside these permanent magnets. The armature has an armature core in which a plurality of teeth are formed radially. A plurality of slots that are long in the axial direction are formed between the teeth, and a coil is formed by winding a winding by a lap winding method between slots having a predetermined interval. The coil is electrically connected to a commutator that is externally fixed to the rotating shaft so as to be adjacent to the armature core.

  In the commutator, a plurality of segments, which are metal pieces, are arranged in the circumferential direction in a state of being insulated from each other, and a winding start end and a winding end end of a coil are connected to these segments, respectively. Each segment is slidably connected to the brush, and power is supplied to each coil via the brush. A magnetic field is formed in the supplied coil, and the rotating shaft is driven by a magnetic attractive force or a repulsive force generated between the yoke and the permanent magnet.

  By the way, in such an electric motor, for example, there is no problem when a pair of brushes reliably contact two of a plurality of segments. However, one brush is in sliding contact with one segment, and the other brush is If the two segments are in sliding contact with each other, there is a difference in the number of coils in the equivalent electric circuit, resulting in variations in the current flowing through the coils, causing vibration and noise in the electric motor. Therefore, in order to obtain an electric motor with a magnetic balance, segments having the same potential may be short-circuited by a connecting line (equal pressure equalization line) (see, for example, Patent Document 1 and Patent Document 2).

Further, for example, as shown in FIG. 8, in order to obtain an electric motor having a magnetic balance, it is conceivable to wind the windings 87 equally in all four directions.
That is, for example, the winding 87 started from the third segment 84e is n times in the forward direction between the slot 83e between the first and second teeth 82 and the slot 83f between the fifth and sixth teeth 82 ( n is a natural number) wound (coil 93A), and next, between slots 83b and 10-11 teeth 82 between 6-7 teeth 82 located 90 ° in the circumferential direction from slots 83e and 83f. It is wound n times in the opposite direction between the slot 83h (coil 93B).

Here, since the coil 93B faces the magnetic poles (permanent magnet 81) having different polarities, the coil 93B is wound in the opposite direction to the coil 93A. Further, in the same procedure, the winding 87 is moved in the forward direction between the slot 83h between the 11th-12th teeth 82 and the slot 83i between the 15th-16th teeth 82 while shifting by 90 ° in the circumferential direction. The coil 93C is formed by winding n times, and the coil 93D is formed between the slot 83d between the 16-17th tooth 82 and the slot 83j between the 20-1st tooth 82. Thereafter, the winding 87 is pulled out from the slot 83j and connected to the fourth segment 84a adjacent to the third segment 84e. With this configuration, it becomes possible to achieve magnetic balance in all directions.
JP 2004-7984 A JP 2005-33843 A

  However, in Patent Document 1 and Patent Document 2 described above, since the segments having the same potential are short-circuited by the connecting line, the number of effective conductors of the energizing coils facing each other around the rotation axis can be made equal. The number of effective conductors of the energization coils adjacent in the circumferential direction is different. For this reason, there is a problem that it is difficult to achieve magnetic balance in all directions, and there is a limit to the reduction of vibration and noise associated therewith.

  On the other hand, as shown in FIG. 8, a winding 87 is wound between slots 93 that are shifted by 90 ° in the circumferential direction in order of the forward direction and the reverse direction, and four coils 93A, 93B, 93C, and 93D are wound. Is formed, the number of parallel circuits is the same as the number of magnetic poles. That is, for example, as shown in FIG. 8, the number of parallel circuits is four in an electric motor 80 having four poles and 20 slots and 20 segments. Therefore, since the number of parallel circuits increases as the number of magnetic poles increases, it is necessary to reduce the diameter of the winding and increase the number of turns of the winding. For this reason, there is a problem that not only winding time increases and manufacturing cost increases, but also tension management of each coil becomes difficult.

  Accordingly, the present invention has been made in view of the above-described circumstances, and can achieve a magnetic balance in all positional relationships, reduce vibration and noise, and can be easily managed and manufactured at a low cost. An electric motor capable of reducing the above is provided.

In order to solve the above-described problems, the invention described in claim 1 includes a rotating shaft that is pivotally supported by a yoke having two or more pole pairs, a radial shaft that is attached to the rotating shaft and extends radially. A plurality of teeth for winding a wire; an armature core having a plurality of slots formed between the teeth and extending along an axial direction; and a plurality of segments provided on the rotating shaft adjacent to the armature core. Each of the windings is electrically connected between adjacent segments, and the windings are wound between slots facing each magnetic pole to form a coil. coil is a wound direction same direction between coils present in the point-symmetric position about the rotation axis, and as wound direction of adjacent coils are opposite to each other, in each circumferential direction equally If the number of pole pairs is P, the number of slots is N, and a is 0 or a positive integer, N is determined so that N = 2P (a + 2) is satisfied, and the commutator has the same potential. A connection line for short-circuiting the segments is provided, and the connection line is connected to each segment so that the coils and the connection line can be wound in series, and is slid onto the segment of the commutator. A brush that can be contacted is provided, and the brush is commonly used for a low-speed brush, a high-speed brush that is spaced apart from the low-speed brush in a circumferential direction by a predetermined angle, and the low-speed brush and the high-speed brush. Common brush, and one of the low-speed brush and the high-speed brush, and the common brush are slid onto one segment. In the state where the other brush of the low-speed brush and the high-speed brush is in sliding contact so as to straddle two adjacent segments, the short-circuited coil and the energized The coils are configured to be equally distributed over the entire circumferential direction .

  The invention described in claim 2 is characterized in that the coil is formed by winding the winding with a short-pitch winding between the slots.

  The invention described in claim 3 is characterized in that the coil is formed by winding the winding with full-pitch winding between the slots.

  According to the present invention, the coils are arranged between the slots so that the winding directions of the coils existing at point symmetry positions around the rotation axis are the same, and the winding directions of adjacent coils are opposite to each other. Since it is wound, a magnetic balance can be achieved in all positional relationships. For this reason, it becomes possible to reduce vibration and noise of the electric motor.

In addition, the commutator is provided with connection lines for short-circuiting the segments having the same potential, and the connection lines are connected one by one between the segments so that the coils and the connection lines can be wound in series.
Therefore, three brushes: a low-speed brush, a high-speed brush that is spaced apart from the low-speed brush by a predetermined angle in the circumferential direction, and a common brush that is commonly used for the low-speed brush and the high-speed brush It is possible to provide an electric motor having two or more pole pairs and capable of switching the rotation speed simply by installing the motor.
In addition, since the number of parallel circuits can be two irrespective of the number of magnetic poles, it is possible to prevent the diameter of the winding from being reduced and to reduce the number of turns of the winding to the teeth. For this reason, the winding time can be reduced, the manufacturing cost can be reduced, and the tension management of each coil can be facilitated.

Next, embodiments of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 to 3, the electric motor 1 is used as a drive source of a power window motor, a wiper motor, a fan motor, and the like of an automobile, for example, and has an armature in a bottomed cylindrical yoke 2. 3 is rotatably arranged. Four permanent magnets 4 are fixed to the inner peripheral surface of the yoke 2 in the circumferential direction. That is, the electric motor 1 of this embodiment is a four-pole electric motor, and the number of pole pairs is two.

  The armature 3 includes an armature core 6 fixed to the rotating shaft 5, an armature coil 7 wound around the armature core 6, and a commutator 13 disposed on one end side of the armature core 6. The armature core 6 is formed by laminating a plurality of metal plates in the axial direction. A plurality of T-shaped teeth 9 (see FIG. 2) are radially formed on the outer peripheral portion of the metal plate at equal intervals along the circumferential direction (20 in this embodiment). By fitting a plurality of metal plates to the rotating shaft 5, dovetail-shaped slots 11 are formed between adjacent teeth 9 on the outer periphery of the armature core 6.

The slots 11 extend along the axial direction, and a plurality (20 in this embodiment) are formed at equal intervals along the circumferential direction.
Here, the number “N” of the slots 11 is determined by the following equation when the number of pole pairs is “P” and “a” is 0 or a positive integer.
N = 2P (a + 2)

That is, in this embodiment, since the number N of the slots 11 is “20” and the number P of pole pairs is “2”, a is “3”, which satisfies the equation.
Further, enamel-wrapped windings 12 are wound between the slots 11, whereby a plurality of armature coils 7 are formed on the outer periphery of the armature core 6.

  The commutator 13 is externally fitted and fixed to one end of the rotating shaft 5. A plurality of segments 14 (20 in this embodiment) formed of a conductive material are attached to the outer peripheral surface of the commutator 13. The segment 14 is made of a plate-like metal piece that is long in the axial direction, and is fixed in parallel at equal intervals along the circumferential direction while being insulated from each other. A riser 15 is integrally formed at an end portion of each segment 14 on the armature core 6 side and is bent in a manner of being folded back to the outer diameter side. A winding 12 serving as a winding start end and a winding end end of the armature coil 7 is wound around the riser 15, and the winding 12 is fixed to the riser 15 by fusing. Thereby, the segment 14 and the armature coil 7 corresponding to this are electrically connected.

  The risers 15 corresponding to the segments 14 having the same potential, that is, the segments 14 facing each other around the rotation shaft 5 (every nine segments 14 in the present embodiment) are respectively connected with the connecting lines 25. The connecting wire 25 is fixed to the riser 15 by fusing (see FIG. 2). The connection line 25 is for short-circuiting the segments 14 having the same potential, and is wired between the commutator 13 and the armature core 6.

  The other end side of the rotating shaft 5 is rotatably supported by a bearing 16 in a boss protruding from the yoke 2. A cover 17 is provided at the open end of the yoke 2, and a holder stay 18 is attached to the inside of the cover 17. Brush holders 19 are formed on the holder stay 18 at three locations in the circumferential direction. In the brush holder 19, the brushes 21 are housed in such a manner that they can be moved in and out in a state where the brushes 21 are urged through the springs S, respectively. Since the tips of these brushes 21 are urged by the spring S, they are in sliding contact with the commutator 13, and external power (not shown) is supplied to the commutator 13 via the brushes 21.

  As shown in detail in FIG. 3, the brush 21 is commonly used for the low-speed brush 21a and the high-speed brush 21b connected to the anode side, and the low-speed brush 21a and the high-speed brush 21b. It is comprised with the connected common brush 21c. The low speed brush 21a and the common brush 21c are disposed at an electrical angle of 180 °, that is, at a mechanical angle of 90 ° in the circumferential direction. On the other hand, the high speed brush 21b is spaced apart from the low speed brush 21a by an angle α in the circumferential direction. In this embodiment, the common brush 21c is described as the cathode side, and the low speed brush 21a and the high speed brush 21b are described as the anode side. However, the anode side and the cathode side may be reversed.

  Here, since the segments 14 having the same potential of the commutator 13, that is, the segments 14 facing each other with the rotation shaft 5 as the center, are short-circuited by the connection line 25, power is supplied to the segments where the brush 21 is not in sliding contact. It becomes possible to do. Therefore, as indicated by a two-dot chain line in FIG. 3, it is considered that the brushes 21a ′, 21b ′, and 21c ′ are also present at positions facing each other around the rotation shaft 5 of each brush 21a, 21b, and 21c. be able to.

According to this, the high speed brush 21b ′ is present at a position advanced by the angle θ relative to the low speed brush 21a.
The electric motor 1 is supplied with power by the common brush 21c and the low speed brush 21a during low rotation driving, and by the common brush 21c and the high speed brush 21b during high rotation driving. For this reason, the electric motor 1 is advanced by the high-speed brush 21b during high rotation driving, and operates at higher rotation than during low rotation driving.

Next, a method for winding the winding 12 around the armature 3 in the electric motor 1 will be described with reference to FIGS. 4 and 5.
4 and 5 are development views of the armature 3, and a gap between adjacent teeth 9 corresponds to the slot 11. In the following drawings, each segment 14 and each tooth 9 will be described with reference numerals.

Here, the segments 14 having the same potential are short-circuited by the connection line 25. That is, in the present embodiment, every other nine segments 14 (for example, the first segment 14a and the eleventh segment 14d) are short-circuited by the connection line 25, respectively. These connection lines 25 are connected one by one between the segments 14 so that the armature coil 7 and the connection line 25 can be wound in series.
In addition, the winding 12 has a winding direction between the slots 11 existing in a point-symmetrical position around the rotation axis 5 between a pair of adjacent segments 14 and the winding direction between the adjacent slots 11. It is wound equally in all directions with short-pitch winding so that the directions are opposite to each other.

More specifically, for example, the winding 12 in which the winding start end 30 is wound around the riser 15 of the 11th segment 14c is first the riser 15 of the 1st segment 14a which is a segment having the same potential as the 11th segment 14c. Multiplied by. Subsequently, the winding 12 is wound n times in the forward direction between the slot 11a between the 19-20th tooth 9 and the slot 11c between the 3-4th tooth 9 to form the coil 7A.
Next, the winding 12 is positioned between the slots 11d between the 4-5th teeth 9 and the slots 11e between the 8th and 9th teeth 9, which are located 90 ° apart from the slots 11a and 11c in the circumferential direction. The coil 7B is formed by winding n times in the reverse direction.

  Here, since the coil 7B faces the magnetic poles (permanent magnet 4) having different polarities, the coil 7B is wound in the opposite direction to the coil 7A. Subsequently, the windings 12 drawn out from the slots 11d between the 4th and 5th teeth 9 are slots 11f and 13 between the 9th and 10th teeth 9 that are located 90 ° apart from the slots 11d and 11e in the circumferential direction. The coil 7C is formed by winding n times in the forward direction between the slots 11g between the -14th teeth 9.

  Further, the winding 12 is reversed between the slot 11h between the 14th to 15th teeth 9 and the slot 11i between the 18th to 19th teeth 9 which are located 90 ° in the circumferential direction from the slots 11f and 11g. The coil 7D is formed by winding n times in the direction. Thereafter, the winding 12 is pulled out from the slot 11h and is wound around the riser 15 of the 12th segment 14d adjacent to the 11th segment 14c.

  Subsequently, the winding 12 wound around the riser 15 of the 12th segment 14d is wound around the riser 15 of the 2nd segment 14b which is a segment having the same potential as the 12th segment 14d. Then, the winding wire 12 is drawn into the slot 11b between the 20th and 9th teeth 9. By sequentially repeating this, a short-pitch armature coil 7 is formed on the armature core 6 by one-stroke operation, and the segments 14 having the same potential are short-circuited.

Therefore, the armature core 6 is wound with the winding 12 between the slots 11 shifted by 90 ° in the circumferential direction while repeating the forward direction and the reverse direction in order, that is, a point-symmetrical position about the rotation axis 5. The four coils 7A, 7B, 7C, and 7D wound so that the winding directions of the coils existing in the same direction are the same and the winding directions of adjacent coils are opposite to each other are formed. Become.
Each connection line 25 is connected to the corresponding segment 14 one by one without being routed all around when short-circuiting the segments 14 having the same potential.

As shown in FIGS. 5 and 6, the armature 3 wound in this way, for example, the low-speed brush 21 a and the common brush 21 c slidably contact the second segment 14 e and the seventh segment 14 f during low-speed driving. In this case, the high-speed brush 21b is in sliding contact with the 13th segment 14g and the 14th segment 14h. At this time, since the 13th segment 14g is short-circuited with the 3rd segment 14b and the 14th segment 14h is short-circuited with the 4th segment 14c, the coils 7A, 7B, 7C, and 7D are short-circuited by the high-speed brush 21b. .
However, since these coils 7A, 7B, 7C, and 7D are wound equally on all four sides, the area of the energized armature coil 7 (the two-dot chain line portion in FIG. 6) becomes equal on all four sides. That is, the number of effective conductors of the four energization coils around the rotating shaft 5 is equal.

Next, the energization state to each armature coil 7 will be described based on FIG.
Here, for example, when the electric motor 1 is driven to rotate at low speed using the low speed brush 21a (anode side) and the common brush 21c (cathode side), the low speed brush 21a is connected to the second segment 14b in sliding contact. The current flows through the armature coil 7 that is connected, and this current continues to flow through each segment 14, the connecting wire 25, and the corresponding armature coil 7 to the seventh segment 14 e where the common brush 21 c is in sliding contact. Go (see solid arrow in FIG. 5).

  On the other hand, the 12th segment 14d is short-circuited by the connection line 25 to the 2nd segment 14b in which the low speed brush 21a is in sliding contact. For this reason, a current also flows through the armature coil 7 connected to the twelfth segment 14d. This current continues to flow through each segment 14, the connecting line 25, and the corresponding armature coil 7 to the seventh segment 14e in which the common brush 21c is in sliding contact (see the broken line arrow in FIG. 5). .

  That is, the current flowing when the low speed brush 21a applies the second segment 14b is connected to the current flowing from the armature coil 7 connected to the second segment 14b toward the common brush 21c and the twelfth segment 14d. The current flowing from the armature coil 7 to the common brush 21c exists in two ways. Therefore, the armature coil 7 wound around the armature core 6 has a structure having two parallel circuits. This is the same even when the electric motor 1 is driven to rotate at high speed using the high-speed brush 21b (anode side) and the common brush 21c (cathode side).

  Therefore, according to the above-described embodiment, the coils 7A, 7B, 7C, and 7D that are short-circuited by the high-speed brush 21b are equally wound in all directions, so that the magnetic balance can be achieved in all positional relationships. It becomes possible. For this reason, the vibration and noise of the electric motor can be further reduced as compared with the prior art.

In addition, the commutator 13 is provided with a connection line 25 for short-circuiting the segments 14 having the same potential, and the connection line 25 can be wound around the armature coil 7 and the connection line 25 one by one between the segments 14. Connected one by one.
Therefore, the low-speed brush 21a, the high-speed brush 21b arranged away from the low-speed brush 21a in the circumferential direction by an angle α, and the low-speed brush 21a and the high-speed brush 21b are commonly used. It is possible to provide the electric motor 1 whose rotational speed can be switched only by installing the three brushes with the brush 21c.
In addition, since the number of parallel circuits can be two regardless of the number of magnetic poles, it is possible to prevent the winding 12 from being reduced in diameter and to reduce the number of turns of the winding 12 around the teeth 9. . For this reason, it is possible to reduce the winding time, reduce the manufacturing cost, and facilitate the tension management of the coils 7A, 7B, 7C, 7D.

The present invention is not limited to the above-described embodiment, and includes various modifications made to the above-described embodiment without departing from the spirit of the present invention.
Moreover, although the above-mentioned embodiment demonstrated the case where the four coils 7A, 7B, 7C, and 7D were formed by winding the coil | winding 12 n between each slot 11, it is restricted to this. Instead, for example, when it is desired to make the total number of turns of the winding 12 odd, that is, when the total number of turns is not broken by “4” which is the number of the coils 7A, 7B, 7C, 7D, The coils 7A, 7B, 7C, and 7D may not all have the same number of turns.

  Furthermore, in the above-described embodiment, the electric motor 1 has four permanent magnets 4 fixed to the yoke 2, 20 slots 11 are formed in the armature core 6, and 20 segments 14 are attached to the commutator 13 4. The case of an electric motor with 20 poles and 20 segments has been described. However, the present invention is not limited to this. When the number of pole pairs is 2 or more, the number of slots 11 is “N”, the number of pole pairs is “P”, and “a” is 0 or a positive integer, N is N = 2P (a + 2) may be satisfied.

  And in the above-mentioned embodiment, the brush 21 is comprised by three brushes of the low speed brush 21a, the high speed brush 21b, and the common brush 21c used in common with these low speed brush 21a and the high speed brush 21b. Explained the case. However, the present invention is not limited to this, and all of the electric motors that have four or more poles and that are provided with the armature coil 7 and the connection line 25 that can be wound in series are connected to the connection line 25 that short-circuits the segments of the same potential. It can be adopted. In other words, the unbalance can be eliminated by using a winding structure of the winding 12 as in the present embodiment for a magnetic imbalance that cannot be eliminated by the connection line 25 alone.

  This can be adopted even when the number of brushes is two or when the number is the same as the number of poles (for example, four in the case of four poles). That is, when the number of brushes is two or four, the magnetic unbalance unlike the three brushes of the present invention hardly occurs, but the winding structure of the winding 12 and the connection line 25 in the present invention. By adopting a structure using the above, it becomes possible to provide an electric motor that is more reliably magnetically balanced.

Further, in the above-described embodiment, the case where the winding 12 is wound with the short-pitch winding between the slots 11 of the armature core 6 has been described. May be.
Furthermore, in the above-described embodiment, the case where the armature core 6 is formed by laminating a plurality of metal plates in the axial direction has been described. However, the present invention is not limited to this, and the armature core is formed by pressing soft magnetic powder. You may form by what is called a dust magnetic body formed by this.

It is a longitudinal section showing the composition of the electric motor in the embodiment of the present invention. It is a top view of the armature in the embodiment of the present invention. It is a layout drawing of the brush in the embodiment of the present invention. It is an expanded view of the armature which shows the winding state of the armature coil in embodiment of this invention. It is an expanded view of the armature which shows the winding state of the armature coil in embodiment of this invention. It is explanatory drawing which shows the short circuit state of the coil in embodiment of this invention. It is an expanded view of the armature which shows the winding state of the conventional coil.

Explanation of symbols

1 Electric motor 2 Yoke 3 Armature 4 Permanent magnet (magnetic pole)
5 Rotating shaft 6 Armature core 7 Armature coils 7A, 7B, 7C, 7D Coil 9 Teeth 11, 11a to 11i Slot 12 Winding 13 Commutator 14 Segment 21 Brush 21a Low speed brush 21b High speed brush 21c Common brush 25 Connection line

Claims (3)

A rotating shaft pivotally supported by a yoke having two or more pole pairs;
A plurality of teeth that are attached to the rotating shaft and extend radially in the radial direction to wind a winding; and an armature core having a plurality of slots formed between the teeth and extending along the axial direction;
The rotating shaft comprises a commutator provided adjacent to the armature core and having a plurality of segments arranged in the circumferential direction.
The winding is electrically connected between adjacent segments, and the winding is wound between slots facing each magnetic pole to form a coil,
Each coil is equally divided in the circumferential direction so that the winding directions of the coils existing at point symmetry positions around the rotation axis are the same and the winding directions of adjacent coils are opposite to each other. It is wound on,
When the number of pole pairs is P, the number of slots is N, and a is 0 or a positive integer,
N = 2P (a + 2)
N is determined so as to satisfy
The commutator is provided with a connection line for short-circuiting the segments having the same potential,
The connection lines are connected one by one between the segments so that the coils and the connection lines can be wound in series .
A brush that can slide in contact with the segment of the commutator is provided,
The brush
A brush for low speed,
A high-speed brush provided at a predetermined angle in the circumferential direction from the low-speed brush;
These brushes are composed of three brushes, a low-speed brush and a common brush commonly used for high-speed brushes.
One of the low-speed brush and the high-speed brush, and the common brush are in sliding contact with one of the segments, and any of the low-speed brush and the high-speed brush In a state where the other brush is in sliding contact with two adjacent segments, the shorted coil and the energized coil are configured to be equally distributed over the entire circumferential direction. An electric motor characterized by that .   The electric motor according to claim 1, wherein the coil is formed by winding the winding with a short-pitch winding between the slots.   2. The electric motor according to claim 1, wherein the coil is formed by winding the winding with full-pitch winding between the slots.

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