JP4503409B2 - Brushless slotless motor - Google Patents

Description

  The present invention relates to a brushless slotless motor.

  The slotless motor is a motor that does not have magnetic pole teeth made of an iron laminated plate or the like as a core of the coil, and therefore there is no space (slot) formed between the magnetic pole teeth. Such a slotless motor has advantages such as (i) no cogging, (ii) low iron loss, and (iii) good compatibility with high-performance magnets such as neodymium magnets.

  Conventionally, as a method of forming a coil of a slotless motor, for example, there is a method proposed in Patent Document 1. In this method, a plurality of coil elements are formed on the outer peripheral surface of the core by repeatedly winding a predetermined number of layers on the peripheral surface of the cylindrical core.

However, in the coil shown in Patent Document 1, since the windings overlap, the coil on the core surface becomes thick, and the gap between the magnet portion provided facing the coil and the core becomes wide. For this reason, it is difficult to narrow the magnetic gap, and a sufficiently large effective magnetic flux cannot be obtained. Therefore, it is difficult to construct a high torque motor. Further, by overlapping the windings, the size of the coil increases, and it is difficult to reduce the size of the entire motor. Further, since the winding is wound obliquely, the winding has an angle with respect to the rotation direction, and the component contributing to torque generation is reduced. Therefore, it is difficult to configure a motor that can efficiently obtain high torque.
JP-A-6-54490

  The present invention has been made in consideration of the above prior art, and an object of the present invention is to provide a slotless motor that can reduce the magnetic gap and make the coil as a whole compact and obtain high output.

The invention of claim 1 includes a rotating shaft, a cylindrical core attached to the rotating shaft, a plurality of flat coil elements attached to the outer peripheral surface of the core, and an outer periphery facing the coil element. A magnet portion composed of a plurality of permanent magnets arranged in a circular arc shape at substantially equal intervals on the side, and a winding end of each coil element disposed at a fixed position with respect to the coil element. In a slotless motor with a brush having a commutator comprising a plurality of segments connected to each other and a plurality of brushes slidably contacting the segments, the coil elements are wound individually by separate windings. Rutotomoni, as energizing direction of the coil elements adjacent a forward or reverse direction opposite said segments, said every two skip between each two Is connected to the coil element to form a continuous series of coils, and both ends of the windings of each coil element intersect each other and one winding end of the adjacent coil element to connect to the segment. The present invention provides a brushless slotless motor.

According to a second aspect of the present invention, in the first aspect of the invention, the coil element has a shape having a longitudinal direction, the longitudinal direction is disposed along the axial direction of the rotating shaft, and the longitudinal direction of the coil element is The coil ends at both ends are bent along the end surface of the core .

According to a third aspect of the present invention, in the first aspect of the present invention, the coil element is formed by winding a strip-shaped iron material .

The invention of claim 4 is characterized in that, in the invention of claim 3 , copper plating is applied to the surface of the band-shaped iron material .

  According to the invention of claim 1, since the plurality of coil elements provided on the surface of the cylindrical core are independently wound in a flat shape, the windings do not overlap and the coil on the core surface does not become thick. . Therefore, the magnetic gap can be narrowed. Therefore, a large effective magnetic flux can be obtained and a high torque motor can be configured. In addition, since there are few crossover portions that do not contribute to torque generation, electrical resistance is low and high output is possible.

  Further, since the windings of the coil elements can be arranged so as to be perpendicular to the rotation direction, torque can be generated effectively and a high output motor can be obtained.

  Furthermore, when the adjacent coil elements are energized in opposite directions, currents in the same direction flow in the adjacent windings. Thereby, loss of electromagnetic energy due to phase shift can be suppressed, and high torque can be obtained efficiently.

Further, when the coil is assembled, in the connection work between the winding end and the commutator, the adjacent coil elements can be connected so as to be energized in opposite directions, thereby preventing a phase shift. For this reason, each coil element may be the same with the winding wound in the same direction, and there is no need to manufacture separate parts. Therefore, management of parts is easy, and the manufacturing process is not complicated.

According to the invention of claim 2 , since the length of the coil element is reduced by bending the coil end, the length of the entire motor can be reduced, and the motor can be further downsized.

According to the invention of claim 3 , since the coil itself provided between the core surface and the magnet portion is a magnetic iron material, the function of the core can be obtained. Accordingly, the magnetic gap is further reduced, and a compact, high torque and large capacity motor can be configured.

According to the invention of claim 4, the iron loss can be kept low by thinning the belt-shaped iron, and the conductivity is improved by copper plating. Further, by changing the ratio of copper and iron, a coil can be freely formed according to the application, such as one having a low electrical resistance or one having a small magnetic gap.

  1 and 2 show an example of the internal configuration of a slotless motor according to the present invention, FIG. 1 is a sectional view in the axial direction, and FIG. 2 is perpendicular to the axial direction cut along line AA in FIG. It is sectional drawing.

  The motor 1 includes a rotor 2 and a stator 3. The rotor 2 includes a rotating shaft 21, a cylindrical core 22 fixed to the rotating shaft 21, a plurality (six in this example) of coil elements 5 attached to the outer peripheral surface of the core 22 at equal intervals, The commutator 6 is used. As will be described later, the coil elements 5 are independently wound in a flat shape. The core 22 that forms the magnetic path of each coil element 5 has a cylindrical shape and does not have magnetic pole teeth that protrude from the cylindrical surface so as to be the core of each coil element 5. Therefore, there are no slots formed between the magnetic pole teeth. Thus, the slotless motor 1 is formed by sticking the flat coil element 5 to the surface of the core 22 made of a simple cylindrical magnetic material (iron). The commutator 6 is fixed to the rotating shaft 21 together with the coil element 5, and includes two segments 6 a that connect the winding end portions 51 for each coil element 5. Accordingly, the number of coil elements 5 as a whole, that is, in the example of FIG. 2, twelve segments 6 a are arranged on the outer peripheral surface of the cylindrical commutator 6 concentric with the rotating shaft 21. The twelve segments 6 a are arranged in a circumferential direction two at a position corresponding to each coil element 5, and are provided in parallel in the circumferential direction on the cylindrical commutator 6. Therefore, the commutator 6 rotates with the coil element 5. The brush 7 is in sliding contact with each segment 6 a of the commutator 6. Alternatively, twelve segments 6a may be provided radially on the end face of the cylindrical commutator 6 (the left end face in FIG. 1), and the brush 7 may be pressed from the end face side.

  The stator 3 includes a case 31 that covers the entire motor 1, a magnet portion 4 including a plurality (four in FIG. 2) of permanent magnets 4 a attached along the inner wall of the case 31, and the brush 7 described above. As shown in FIG. 2, the permanent magnet 4 a is arranged on the inner wall of the case 31 by being divided into arcs at substantially equal intervals. Therefore, the case 31 constitutes the core (yoke) of the magnet unit 4. The brush 7 contacts the commutator 6 via a spring 72 attached in the brush holder 71, and sequentially contacts the segment 6 a of the commutator 6 when the rotor 2 rotates. At least one brush 7 connected to the power source of each of the positive electrode and the negative electrode is provided and supplies power to each coil element 5 via the segment 6a.

  FIG. 3 is a plan view of a shape example of the coil element 5. The coil element 5 does not have a core such as magnetic pole teeth, and is formed in a flat shape by winding the winding thinly, for example, in one layer or two to three layers. In the example of FIG. 2, six coil elements 5 are provided, each coil element 5 is wound independently by a separate winding, is solidified by resin, and is attached to the core 22. The winding tip 51 of each coil element 5 is connected to the segment 6a of the commutator 6 as described above. The coil element 5 has a longitudinal direction, and is affixed to the surface of the cylindrical core 22 so that the long axis 5c is parallel to the rotating shaft 21 (FIG. 1).

  FIG. 4 is an external view of a different coil element 5a of the present invention. In this example, a coil element 5a is formed by winding an iron material 52, which is a strip-like conductive magnetic body. In order to increase conductivity, the iron material 52 may be plated with copper. Moreover, you may interpose the insulating film 53 between the iron materials 52 to wind. Alternatively, an insulating film may be coated on the surface of the iron material 52 instead of the insulating film 53.

  Thus, by forming the coil element 5a using the strip-shaped iron material 52, the iron material 52 itself, which is a magnetic material, also serves as a yoke that forms the magnetic path of the permanent magnet 4a. A magnetic gap with the cylindrical core 22 is further narrowed, and high torque can be obtained.

  Since the coil elements 5 and 5 a are attached to the surface of the cylindrical core 22, the coil elements 5 and 5 a have an arcuate cross-sectional shape along the outer peripheral shape of the core 22 as shown in FIG. 2. This curved surface may be formed after the coil elements 5 and 5a are wound, or may be formed at the time of winding.

  FIGS. 5 to 7 are examples of different coil elements 5 b of the present invention, in which coil ends 54 positioned at both axial ends of the rotating shaft 21 of the motor 1 are bent along the cylindrical end surface of the core 22. is there. FIG. 5 is a side view showing only the coil portion of the motor, and FIG. 6 is a plan view of the coil element 5b alone. FIG. 7 is a front view of the motor 1a when the coil element 5b is used. Thus, by bending the coil end 54, the length of the coil element can be reduced, and the entire motor 1a can be reduced in size.

  FIG. 8 is a development view of a coil connection example of the slotless motor of the present invention. That is, for example, as shown in FIG. 2, this is an example of connection when there are six coil elements 5, and both ends of the winding of each coil element 5 are connected to the segment 6 a of the commutator 6.

  Corresponding to the positions of the six coil elements 5, a total of twelve segments 6a are provided, each having two segments 6a. As shown in FIG. 8, both ends of the windings of each coil element 5 intersect with each other and intersect with one winding end of the adjacent coil element 5 and are connected to the segment 6a. The winding end of the coil element 5 is connected to the far segment of the two segments 6a directly below, or to the distant segment 6a of the two segments 6a directly below the adjacent coil element 5. The coil element 5 connected to the segment 6a directly below each coil element 5 and the coil element connected to the segment 6a directly below the adjacent coil element 5 are alternately arranged. Accordingly, the segments 6a are skipped by two and connected to the coil element 5 every two to form a series of coils. Thereby, as shown in FIG. 8, six coil elements 5 are connected using six of # 1, # 2, # 5, # 6, # 9, and # 10 out of twelve segments 6a. A series of coils is formed. By performing such connection, a series of coils can be formed such that the energization directions of adjacent coil elements 5 are arranged in the normal and reverse order. Thereby, the direction of the current flowing through the windings of adjacent coil elements 5 is the same direction, energy loss is suppressed, and phase shift can be prevented.

  9 (A) to 9 (C) show the operation of the coil according to the connection example of FIG. 8. From the state of FIG. 9 (A), as the rotor 2 rotates, the brush 7 is relatively half right of the segment 6a. The state moved in the direction is shown.

  In the present embodiment, there are four permanent magnets 4a constituting the magnet part 4, two brushes 7 each on the "+" side and "-" side, and the magnet part 4 and the brush 7 are on the stator side. As the coil element 5 and the segment 6 a rotate, the brush 7 sequentially contacts the segment 6 a and supplies power to each coil element 5.

  When power is supplied from the “+” side to the “−” side via the brush 7, a current flows in each coil element 5 in the direction of the arrow, and the rotor 2 rotates. When the coil element 5 and the segment 6a constituting the rotor 2 are rotated, the brushes 7 sequentially come into contact with the segments 6a, and a current flows from “+” to “−” through the respective brushes 7. The coil element 5 indicated by a dotted line in the figure is not energized depending on the contact position of the brush 7, and this is the same in FIG. By connecting as shown in the figure, in each coil element 5, as indicated by the arrows in the figure, current flows between the adjacent coil elements 5 in the opposite direction, and the adjacent windings are directed in the same direction. Current flows. Therefore, energy loss is reduced, phase shift can be prevented, and high torque can be obtained. Moreover, the space | interval between adjacent brushes 7 is an area including the clearance gap between the two segments 6a. As described above, by including two or more gaps between the segments 6a serving as the insulating regions, the insulation is improved and the withstand voltage is improved.

  FIG. 10 is a developed view of different connection examples of the coil of the present invention. The connection between the coil element 5 and the segment 6a is the same as in FIG. 8, and the segments 6a are connected to each other. As shown in the figure, the segments 6a are connected to # 1 and # 7, # 2 and # 8, # 3 and # 9, # 4 and # 10, # 5 and # 11, # 6 and # 12 of the segment 6a. As shown, two segments 6a are connected. By connecting the segments 6a to each other, a single brush 7 can supply power to the plurality of segments 6a at the same time, so the number of brushes 7 can be reduced. According to the example of FIG. 10, by providing one brush 7 on each of the “+” side and the “−” side, a current flows through each coil element 5 as in FIG.

  FIG. 11 is an explanatory diagram of different connection examples of the coil of the present invention, and is formed by stacking another series of coils using six unused segments 6a in the connection example of FIG.

  First, as shown in FIG. 11A, the same connection as in FIG. 8 is performed. That is, a series of coils is formed using six of the segments, # 1, # 2, # 5, # 6, # 9, and # 10. Thereafter, as shown in FIG. 11B, the remaining six segments 6a (# 3, # 4, # 7, # 8, # 11, # 12) are used in the same manner as in (A). Another series of coils is formed. By superimposing FIG. 11 (A) and FIG. 11 (B), as shown in FIG. 11 (C), a coil in which all the segments 6a are equally used is formed. Thereby, the use efficiency of the segment 6a is improved, and a stable high output is obtained. Further, since the sliding frictional resistance against the brush 7 becomes substantially constant during rotation, the durability of the brush 7 is increased. In FIG. 11C, the series of coils formed in FIG. 11B are indicated by thin lines. In the example of FIG. 11, the segments 6a are not connected to each other. However, the brushes 7 can be reduced to two by connecting the segments 6a to each other as in the example of FIG.

  FIG. 12 is an explanatory diagram of an embodiment of a further different coil, in which the width of the brush 7 is made larger than that of the above-described embodiment. 12A to 12C show a state in which the brush 7 is relatively moved to the right in the figure by half of the segment 6a by the rotation of the rotor 2. In this case, the segments 6a are not connected to each other.

  By increasing the width of the brush 7, the interval between the brushes 7 is narrower than that in the above-described embodiment. In this example, there is only one gap between the segments 6a at the position of FIG. 12 (B), and the withstand voltage is lowered, but at the positions of FIG. 12 (A) and FIG. A gap between the segments 6a is included. Thus, by setting the interval between the brushes 7 to include at least two gaps between the segments 6a at least at one location during rotation, the average interval between the brushes 7 is widened and sufficiently large. Withstand voltage can be obtained. Therefore, it is not necessary to make the width of the brush 7 too small in order to increase the withstand voltage, the restriction on the width of the brush 7 is reduced, and the degree of freedom of design is expanded.

  FIG. 13 and FIG. 14 are development views of different coil embodiments, in which the number of coil elements 5 and brushes 7 is different. FIG. 13 shows the case where the number of coil elements 5 is 8, the number of segments 6a is 16, the number of permanent magnets 4a is 6, and the number of brushes 7 is 3 each on the “+” side and the “−” side. FIG. 14 shows an example of connection when the number of coil elements 5 is 10, the number of segments 6a is 20, the number of permanent magnets 4a is 8, and the number of brushes 7 is 4 each on the “+” side and the “−” side. Increasing the number of brushes 7 eliminates the need for connecting the segments 6a.

  The connection method of the coil element 5 and the segment 6a is the same as that of the above-described connection shown in FIG. 8, and the energization directions of the adjacent coil elements 5 are opposite to each other as shown by the arrows in the figure. A series of coils can be formed. Two or more segments 6a may be connected to reduce the number of brushes 7.

  FIG. 15 is a development view of a further different embodiment, in which three coil elements 5 are provided in a space in which six coil elements 5 can be disposed. That is, a space for one coil element 5 is provided in between, and two coil elements 5A and 5B are formed to overlap each other, and these are formed using six segments 6a out of twelve segments 6a. Connected to form a series of coils.

  As shown in the drawing, one of the two coil elements 5A and 5B formed in an overlapping manner is connected to two adjacent segments 6a with their winding ends intersecting each other. The other coil element 5B is connected to a segment 6a in which both winding ends are spaced apart from each other. Similarly to the above-described embodiment, the segments 6a are connected to the coil element 5 at intervals of two.

  FIG. 16 is a diagram in which another series of coils having the same shape as in FIG. 15 is formed and overlapped using three spaces and six segments 6a that are not used in the embodiment of FIG. FIG. 16A is the same as FIG. 15, and two coil elements 5A and 5B are formed in one coil element space. FIG. 16 (B) shows another series of coils with the same shape as FIG. 15 but not used in FIG. 16 (A) and a segment 6a, with two coil elements in one coil element space. 5C and 5D are formed and connected to form a series of coils. FIG. 16C is a superposition of FIG. 16A and FIG. In FIG. 16C, the series of coils formed in FIG. 16B are indicated by thin lines.

  In all the above embodiments, the number of coil elements 5 and brushes 7 is not limited to the above example.

  In the slotless motor, the core including the coil element 5 is the rotor 2 side. However, the present invention can be similarly implemented even in an outer rotor system in which the magnet unit 4 rotates.

  The present invention can be applied to a brushless slotless motor installed in a narrow space.

Sectional drawing which shows the internal structure of the slotless motor which concerns on this invention. Sectional drawing cut | disconnected by the AA line of FIG. The top view which shows the coil element single-piece | unit of FIG. The perspective view which shows different embodiment of a coil element single-piece | unit. The side view which shows different embodiment of a coil element. The top view which shows the coil element single-piece | unit of FIG. The front view of the slotless motor using the coil element of FIG. The expanded view which shows embodiment of the coil of this invention. Operation | movement explanatory drawing of embodiment of FIG. The expanded view of different embodiment of the coil of this invention. Explanatory drawing of further different embodiment of the coil of this invention. Operation | movement explanatory drawing of further different embodiment of the coil of this invention. The expanded view of further different embodiment of the coil of this invention. The expanded view of further different embodiment of the coil of this invention. The expanded view of further different embodiment of the coil of this invention. Explanatory drawing of further different embodiment of the coil of this invention.

Explanation of symbols

1, 1a: motor, 2: rotor, 3: stator, 4: magnet part, 4a: permanent magnet, 5, 5a, 5b, 5A, 5B, 5C, 5D: coil element, 6: commutator, 6a: segment, 7 : Brush, 21: rotating shaft, 22: core, 31: case, 51: winding end, 52: iron material, 53: insulating film, 54: coil end, 71: brush holder, 72: spring.

Claims (4)

A rotating shaft, a cylindrical core attached to the rotating shaft, and a plurality of flat coil elements attached to the outer peripheral surface of the core;
A magnet portion composed of a plurality of permanent magnets arranged at substantially equal intervals in a circular arc shape on the outer peripheral side facing the coil element,
A commutator comprising a plurality of segments, which are arranged at a fixed position with respect to the coil element via a certain gap, and to which winding ends of the coil elements are connected;
In a slotless motor with a brush having a plurality of brushes in sliding contact with the segment,
The coil elements are wound individually by separate windings, and the energizing directions of adjacent coil elements are opposite to the forward and reverse directions.
The segments are separated from each other by two and connected to the coil element every two to form a continuous series of coils, and both ends of the windings of each coil element intersect with each other and the adjacent coil. A brushless slotless motor characterized by being connected to the segment crossing one winding end of the element . The coil element has a shape having a longitudinal direction, the longitudinal direction is disposed along the axial direction of the rotating shaft, and the coil ends at both ends in the longitudinal direction of the coil element are bent along the end surface of the core. The brushless slotless motor according to claim 1, wherein the brushless slotless motor is provided. The slotless motor with a brush according to claim 1, wherein the coil element is formed by winding a strip-shaped iron material . The brushless slotless motor according to claim 3, wherein a copper plating is applied to a surface of the belt-shaped iron material .

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