Motor

According to the present invention, a coil is continuously wound in a single pass around each of a series of teeth, and connected to each segment.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a 371 application of the international PCT application serial no. PCT/JP2018/040278, filed on Jan. 10, 2018, which claims the priority benefit of Japan application no. 2018-002168, filed on Jan. 10, 2018. The entirety of each of the above-mentioned patent applications is hereby incorporated by reference herein and made a part of this specification.

TECHNICAL FIELD

The present invention relates to a motor.

RELATED ART

Among motors, there is a three-phase brushed DC motor (hereinafter referred to as a brushed motor) mounted on a vehicle or the like. This brushed motor includes a cylindrical yoke having a permanent magnet attached to an inner peripheral surface thereof, and an armature rotatably provided radially inside the yoke.

The armature has a rotary shaft, an armature core externally fitted and fixed to the rotary shaft, and a commutator externally fitted and fixed to the rotary shaft so as to be adjacent to the armature core.

The armature core has a plurality of teeth extending along a radial direction and disposed radially. Dovetail groove-like slots are formed between each tooth adjacent in a circumferential direction. A coil is wound around each tooth via these slots.

A plurality of segments are disposed on the commutator along the circumferential direction. The coil is connected to these segments. A brush comes into slide contact with each segment. The brush is electrically connected to an external power supply. By applying the power of the external power supply to each segment via the brush, a current is supplied to each coil.

Accordingly, a predetermined magnetic field is formed in the armature core, and magnetic attractive force or repulsive force is generated between the magnetic field and the permanent magnet. Hence, the armature rotates.

In addition, by the rotation of the armature, the segments with which the brush comes into slide contact are sequentially changed, and so-called rectification is performed in which the direction of the current supplied to the coil is switched. Accordingly, the armature continuously rotates.

As a means of reducing the size and weight of the motor, it is conceivable to increase the number of poles of the permanent magnet. By increasing the number of poles, it is possible to reduce the amount of effective magnetic flux per magnetic pole. As a result, the armature core that forms magnetism can be reduced in size and weight.

If it is simply attempted to increase the number of poles, the number of slots increases. Thus, if an outer diameter of the armature core is to be kept constant, the slots may become small. As a result, a coil winding operation may become difficult. Hence, various techniques have been proposed capable of downsizing the motor while facilitating the coil winding operation.

For example, there are six teeth and twelve segments, and when the teeth are sequentially numbered from 1 to 6 in the circumferential direction and the segments are sequentially numbered from 1 to 12 in the circumferential direction, a winding start terminal of the coil is connected to the seventh segment. The coil is connected from the seventh segment to the first segment, and is wound around the first tooth in a forward direction from the first segment. The coil is connected from the first tooth to the second segment, and is connected from the second segment to the eighth segment. The coil is wound around the third tooth in a reverse direction from the eighth segment, and is connected from the third tooth to the third segment. The coil is connected from the third segment to the ninth segment, and is wound around the fifth tooth in the forward direction from the ninth segment. The coil is connected from the fifth tooth to the tenth segment, and is connected from the tenth segment to the fourth segment. The coil is wound around the first tooth in the reverse direction from the fourth segment, and is connected from the first tooth to the eleventh segment. The coil is connected from the eleventh segment to the fifth segment, and is wound around the third tooth in the forward direction from the fifth segment. The coil is connected from the third tooth to the sixth segment, and is connected from the sixth segment to the twelfth segment. The coil is wound around the fifth tooth in the reverse direction from the twelfth segment. A winding end terminal pulled out from the fifth tooth is again connected to the seventh segment. The segments having the same potential are short-circuited by an equalizer (connection line) (for example, see Patent Document 1).

For example, each tooth includes a first coil electrically connected between adjacent segments and wound in the forward direction, and a second coil electrically connected between other adjacent segments and wound in the reverse direction. Relative positions of the segment to which the winding start terminal of the first coil is connected and the segment to which the winding start terminal of the second coil is connected are set to correspond to relative positions of a pair of brushes. The segments having the same potential are short-circuited by an equalizer (connection line) (for example, see Patent Document 2).

Patent Documents

Patent Document 1: Japanese Laid-open No 2017-131035

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

However, in Patent Document 1 described above, segments exist to which the coil wound around the teeth is not connected. In the case where a brush comes into slide contact with such a segment, the value of the current flowing through the equalizer may increase, and there is a possibility that the equalizer may be damaged. In addition, since the equalizer needs to be pulled around by another apparatus, there is a possibility that a winding device may become complex.

A more specific description is given based onFIG. 4.

FIG. 4is an explanatory diagram showing an electric circuit of a coil207in Patent Document 2.

As shown inFIG. 4, for example, in the case where a brush222is in slide contact with the first segment214and the fourth segment214respectively, the coil207is in a form in which electric circuits are connected in parallel between the seventh segment214connected with the first segment214via an equalizer252and the tenth segment214connected with the fourth segment214via the equalizer252.

Hence, for example, in the case where a current supplied to the brush222has a current value of 4[i], although a current supplied to the coil207has a current value of 2[i], a current supplied to the equalizer252between the first and seventh segments214has a current value of 4[i]. Similarly, the current supplied to the equalizer252between the fourth and tenth segments214also has a current value of 4[i].

In this way, the value of the current flowing through the equalizer252may increase, and there is a possibility that the equalizer252may be damaged.

In contrast, in Patent Document 2 described above, since the coil wound around the teeth is connected to each segment, the value of the current flowing through the equalizer can be reduced as compared with Patent Document 1 However, to realize a coil winding structure as in Patent Document 2, it is necessary for the winding device to perform the coil winding operation on two coils simultaneously by a so-called double flyer that has two flyers for drawing the coils. For this reason, the winding device becomes complex. In addition, since the double flyer is used, the amount of winding of the coil is increased, and there is a problem that it is difficult to improve a space factor of the coil.

It is not impossible to perform the coil winding operation by a single flyer having one flyer, instead of using the double flyer. However, even if it is attempted to wind the coil by the single flyer as by the double flyer, if the same number of turns as that of the double flyer is not reached, it is difficult to achieve the same motor characteristics, and the number of winding steps may simply be doubled. In addition, when the coil is pulled around in order to be wound around each tooth, the previously wound coil causes interference and the winding operation itself is troublesome.

Therefore, the present invention provides a motor that can be reduced in size and that is capable of reducing the value of the current flowing through the equalizer, simplifying the winding device, improving the space factor of the coil, and facilitating the winding operation.

Means for Solving the Problems

In order to solve the above problems, according to a first aspect of the present invention, a motor includes: a yoke having four magnetic poles; an armature core, having a rotary shaft rotatably provided radially inside the yoke, six teeth attached to the rotary shaft and extending radially outward, and six slots formed between each of the teeth adjacent in a circumferential direction, a coil wound around each of the teeth; a commutator provided adjacent to the armature core on the rotary shaft, on which twelve segments are disposed in the circumferential direction; and a plurality of brushes supplying power to the coil via each of the segments. When the teeth are sequentially numbered from 1 to 6 in the circumferential direction and the segments are sequentially numbered from 1 to 12 in the circumferential direction, a winding start terminal of the coil is connected to the first segment, and the coil is pulled around in one direction in a rotational direction of the rotary shaft from the first segment and wound around the fifth tooth in a forward direction, pulled around in the one direction from the fifth tooth and wound around the second tooth in the forward direction, pulled around in the one direction from the second tooth and connected to the twelfth segment, pulled around in the one direction from the twelfth segment and connected to the sixth segment, pulled around in the one direction from the sixth segment and wound around the sixth tooth in a reverse direction opposite the forward direction, pulled around in the one direction from the sixth tooth and wound around the third tooth in the reverse direction, pulled around in the one direction from the third tooth and connected to the eleventh segment, pulled around in the one direction from the eleventh segment and connected to the fifth segment, pulled around in the one direction from the fifth segment and wound around the first tooth in the forward direction, pulled around in the one direction from the first tooth and wound around the fourth tooth in the forward direction, pulled around in the one direction from the fourth tooth and connected to the fourth segment, pulled around in the one direction from the fourth segment and connected to the tenth segment, pulled around in the one direction from the tenth segment and wound around the second tooth in the reverse direction, pulled around in the one direction from the second tooth and wound around the fifth tooth in the reverse direction, pulled around in the one direction from the fifth tooth and connected to the third segment, pulled around in the one direction from the third segment and connected to the ninth segment, pulled around in the one direction from the ninth segment and wound around the third tooth in the forward direction, pulled around in the one direction from the third tooth and wound around the sixth tooth in the forward direction, pulled around in the one direction from the sixth tooth and connected to the eighth segment, pulled around in the one direction from the eighth segment and connected to the second segment, pulled around in the one direction from the second segment and wound around the fourth tooth in the reverse direction, pulled around in the one direction from the fourth tooth and wound around the first tooth in the reverse direction, pulled around in the one direction from the first tooth and connected to the seventh segment, and pulled around in the one direction from the seventh segment and connected to the first segment.

By being configured in this way, the motor can be reduced in size, and the coil wound around the teeth can be connected to each segment. Hence, it can be prevented that a value of a current flowing through the coil connecting the segments having the same potential may increase.

In addition, by a single flyer, the coil winding operation can be performed continuously in a single stroke. Hence, a winding device can be simplified and the coil winding operation can be facilitated.

Here, copper forming each coil is coated. At that time, the coating is performed in which the amount of coating has substantially the same thickness even when wire diameters are different. Hence, compared to the case where the coil is wound by a double flyer, in the case where the coil is wound by a single flyer, the number of turns of the coil can be reduced and the amount of coating can be reduced. As a result, it is possible to improve the space factor of the coil.

Effects of the Invention

According to the above motor, a motor can be provided that can be reduced in size and that is capable of reducing a value of a current flowing through a connection line, simplifying a winding device, improving a space factor of a coil, and facilitating a winding operation.

DESCRIPTION OF THE EMBODIMENTS

Next, an embodiment of the present invention is described based on the drawings.

FIG. 1is a cross-sectional view of a brushed motor1along an axial direction.

The brushed motor1is, for example, used as a driving source for electrical equipment mounted on a vehicle.

As shown inFIG. 1, the brushed motor1includes an armature3rotatably provided in a substantially bottomed cylindrical yoke2, and an opening part2cof the yoke2is closed with an end bracket17.

Four permanent magnets4are fixed to an inner peripheral surface of the yoke2in a circumferential direction. That is, there are four magnetic poles.

The armature3includes an armature core6fixed to a rotary shaft5, a coil7wound around the armature core6, and a commutator13disposed at one end of the armature core6. The armature core6is formed by, for example, laminating a plurality of ring-shaped metal plates8in the axial direction. However, the armature core6may be formed by compression molding soft magnetic powder.

On an outer peripheral part of the metal plates8, six T-shaped teeth50are formed radially at equal intervals along the circumferential direction when viewed from the axial direction Since the plurality of metal plates8are externally fitted to the rotary shaft5, dovetail groove-like slots51are formed between adjacent teeth50on an outer periphery of the armature core6. The slots51extend along the axial direction, and there are six slots51formed at equal intervals along the circumferential direction. Through these slots51, the coil7is wound around the teeth50by a concentrated winding method (the details will be described later).

The commutator13is externally fitted and fixed to one end of the rotary shaft5. Twelve segments14formed of a conductive material are attached to an outer peripheral surface of the commutator13. In this way, the brushed motor1of the present embodiment is a so-called four-pole six-slot twelve-segment (double segment) motor, having four permanent magnets4(the number of magnetic poles is four), six slots51(six teeth50), and twelve segments14.

The segments14are formed of plate-shaped metal pieces that are long in the axial direction, and are fixed in parallel at equal intervals along the circumferential direction while being insulated from each other. At an end part of each segment14toward the armature core6, a riser15bent in the form of being folded back to an outer diameter side is formed integrally with the segment14. The coil7wound around the teeth50is wound around the riser15and fixed by, for example, fusing. Accordingly, the segments14and the corresponding coil7are electrically connected.

In addition, the coil7is connected so that predetermined two of the segments14, that is, two segments14having the same potential, are short-circuited (seeFIG. 2; the details will be described later). The coil7that short-circuits the two segments14having the same potential functions as an equalizer (connection line)52. These equalizers52are also wound around the riser15of the predetermined segments14and fixed by, for example, fusing.

The other end of the rotary shaft5is rotatably supported by a bearing12in a boss formed protruding from a bottom part2bof the yoke2. The end bracket17is provided at an end of the yoke2toward the opening part2c. A holder stay20is attached inside the end bracket17. A pair of brush holders21at a 90° interval in the circumferential direction, for example, is formed on the holder stay20. The brush holders21are respectively equipped with brushes22that are freely retractable while being energized via a spring23.

Each brush22is electrically connected to an external power supply via a pigtail16. Each brush22is classified into a positive brush and a negative brush. Tip parts of these brushes22come into slide contact with the commutator13because they are energized by the spring23, and external power is supplied to the commutator13via the brushes22.

Next, a method for winding the coil7is described based onFIG. 2.

FIG. 2is an expanded view of the permanent magnets4as well as the teeth50, the segments14, and the coil7(equalizers52) of the armature3, wherein gaps between the adjacent teeth50correspond to the slots51.

As shown inFIG. 2, the armature3has a three-phase (U-phase, V-phase, and W-phase) structure, and each tooth50is assigned as the U-phase, the V-phase, and the W-phase in this order along the circumferential direction. In the following description, the phases and numbers assigned to each tooth50are sequentially assigned, and each segment14is sequentially numbered in the circumferential direction and described. Although inFIG. 2, each segment14is numbered so that the first segment14is located in the vicinity of the tooth50numbered U1(1), the present invention is not limited thereto and the location of the first segment14can be set arbitrarily.

The coil7is continuously pulled around each tooth50and each segment14in a single stroke. In addition, the coil7is always pulled around in one direction in a rotational direction of the armature3(rotary shaft5). InFIG. 2, the coil7is pulled around to the right.

That is, firstly, a winding start terminal7aof the coil7is connected to the first segment14. Subsequently, the coil7is wound around the tooth50numbered V2(5) in a forward direction (clockwise direction inFIG. 2) from the first segment14to form a second V-phase forward coil72Va.

Subsequently, the coil7is pulled out from the tooth50numbered V2(5), and the coil7is wound around the tooth50numbered V1(2) in the forward direction to form a first V-phase forward coil71Va.

Subsequently, the coil7is pulled out from the tooth50numbered V1(2), and the coil7is wound around the riser15of the twelfth segment14.

Subsequently, the coil7is wound around the riser15of the sixth segment14from the twelfth segment14.

Subsequently, the coil7is pulled out from the sixth segment14, and the coil7is wound around the tooth50numbered W2(6) in a reverse direction (counterclockwise direction inFIG. 2) to form a second W-phase reverse coil72Wb.

Subsequently, the coil7is pulled out from the tooth50numbered W2(6), and the coil7is wound around the tooth50numbered W1(3) in the reverse direction to form a first W-phase reverse coil71Wb.

Subsequently, the coil7is pulled out from the tooth50numbered W1(3), and the coil7is wound around the riser15of the eleventh segment14.

Subsequently, the coil7is wound around the riser15of the fifth segment14from the eleventh segment14.

Subsequently, the coil7is pulled out from the fifth segment14, and the coil7is wound around the tooth50numbered U1(1) in the forward direction to form a first U-phase forward coil71Ua.

Subsequently, the coil7is pulled out from the tooth50numbered U1(1), and the coil7is wound around the tooth50numbered U2(4) in the forward direction to form a second U-phase forward coil72Ua.

Subsequently, the coil7is pulled out from the tooth50numbered U2(4), and the coil7is wound around the riser15of the fourth segment14.

Subsequently, the coil7is wound around the riser15of the tenth segment14from the fourth segment14.

Subsequently, the coil7is pulled out from the tenth segment14, and the coil7is wound around the tooth50numbered V1(2) in the reverse direction to form a first V-phase reverse coil71Vb.

Subsequently, the coil7is pulled out from the tooth50numbered V1(2), and the coil7is wound around the tooth50numbered V2(5) in the reverse direction to form a second V-phase reverse coil72Vb.

Subsequently, the coil7is pulled out from the tooth50numbered V2(5), and the coil7is wound around the riser15of the third segment14.

Subsequently, the coil7is wound around the riser15of the ninth segment14from the third segment14.

Subsequently, the coil7is pulled out from the ninth segment14, and the coil7is wound around the tooth50numbered W1(3) in the forward direction to form a first W-phase forward coil71Wa.

Subsequently, the coil7is pulled out from the tooth50numbered W1(3), and the coil7is wound around the tooth50numbered W2(6) in the forward direction to form a second W-phase forward coil72Wa.

Subsequently, the coil7is pulled out from the tooth50numbered W2(6), and the coil7is wound around the riser15of the eighth segment14.

Subsequently, the coil7is wound around the riser15of the second segment14from the eighth segment14.

Subsequently, the coil7is pulled out from the second segment14, and the coil7is wound around the tooth50numbered U2(4) in the reverse direction to form a second U-phase reverse coil72Ub.

Subsequently, the coil7is pulled out from the tooth50numbered U2(4), and the coil7is wound around the tooth50numbered U1(1) in the reverse direction to form a first U-phase reverse coil71Ub.

Subsequently, the coil7is pulled out from the tooth50numbered U1(1), and the coil7is wound around the riser15of the seventh segment14.

Subsequently, the coil7is pulled out from the seventh segment14, and a winding end terminal7bof the coil7is connected to the first segment14. Accordingly, a winding operation of the coil7is completed.

(About Electric Circuit of Coil)

Next, an electric circuit of the coil7wound as described above is described based onFIG. 3.

FIG. 3is an explanatory diagram showing an electric circuit of the coil7.

As shown inFIG. 3, for example, in the case where the brush22is in slide contact with the first segment14and the fourth segment14respectively, a circuit to which the coil7is connected in series is formed between the first and fourth segments14, and a circuit to which the coil7is connected in series is formed between the seventh and tenth segments14. These two circuits are connected in parallel. Hence, for example, in the case where a current value supplied to the brush22is 4[i], currents supplied to each circuit each have a current value of 2[i] In addition, a current supplied to the equalizer52also has a current value of 2[i].

In this way, in the above-described embodiment, while the brushed motor1can be reduced in size, the coil7wound around each tooth50can be connected to each segment14. Hence, it can be prevented that the value of the current flowing through the coil7connecting the segments14having the same potential may increase.

In addition, by a single flyer, the winding operation of the coil7can be performed continuously in a single stroke. Hence, a winding device can be simplified and the winding operation of the coil7can be facilitated.

In addition, compared to the case where the coil7is wound by a double flyer, since the coil7is wound by a single flyer, the number of turns of the coil7can be reduced, and the amount of coating of the coil7can be reduced. As a result, it is possible to improve a space factor of the coil7.

The present invention is not limited to the above-described embodiment, and includes various modifications of the above-described embodiment without departing from the spirit of the present invention.

For example, in the above-described embodiment, the case is described where the brushed motor1is used as the driving source for electrical equipment (for example, a power window) mounted on a vehicle. However, the present invention is not limited thereto, and the brushed motor1can be employed for driving various machines.

INDUSTRIAL APPLICABILITY

According to the above motor, a motor can be provided that can be reduced in size and that is capable of reducing a value of a current flowing through a connection line, simplifying a winding device, improving a space factor of a coil, and facilitating a winding operation.