JP2014193069A - Coreless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coreless motor capable of improving a problem that a current in such a direction that a torque is reduced flows in a part of a coil, and of obtaining a high efficiency.SOLUTION: A coreless motor comprises an amateur 116 having a coil forming assembly 109 configured by coil segments 210-230. When the number of poles of the amateur is defined as N, a coil width of the coil segments 210-230 is (360°/2N) in terms of an angle. Both ends of the coil segments 210-230 are respectively connected with commutator risers 111a-111c from an angle position shifted by (360°/4N) to the commutator risers 111a-111c.

Description

  The present invention relates to a coreless motor characterized by a coil structure.

  There is known a coreless motor in which an amateur is formed by a coil (winding) without using a core (iron core). Since the coreless motor has no core, it is known that the armature has a low moment of inertia, excellent responsiveness, no cogging torque, no iron loss, and high efficiency. For example, Patent Document 1 discloses a coil for a coreless motor in which coils formed in a hexagonal shape are joined to form a cylindrical shape.

Japanese Patent Laid-Open No. 5-30721

  In the conventional winding method as described in Patent Document 1, a current in a direction that generates torque in a direction opposite to the rotation direction of the motor flows in a part of the winding, so that the maximum efficiency of the motor is limited. The In particular, this problem becomes apparent when the number of amateur poles is small. In such a background, the present invention provides a coreless motor that improves the problem that a current flowing in a direction that generates torque in a direction opposite to the rotation direction of the motor flows in a part of the winding, and obtains high efficiency. Objective.

  The invention according to claim 1 includes an armature composed of a plurality of coil segments, and the coil width of the plurality of coil segments is taken as an angle with the number of poles of the armature being N (360 ° / 2N). In the coreless motor, both ends of the plurality of coil segments are respectively connected to the commutator riser from an angular position shifted by (360 ° / 4N) with respect to the commutator riser.

  The invention according to claim 2 is provided with an armature composed of a plurality of coil segments, and the coil width of the plurality of coil segments is taken as an angle with the number of poles of the armature being N (360 ° / 2N). The plurality of coil segments have a structure in which a polygonal cylindrical coil is crushed in the axial direction and processed into a planar shape, and the amateur has the plurality of coil segments arranged along a cylindrical surface. Coil segments that have a structure and are adjacent in the circumferential direction in the thickness direction of the amateur are arranged in a state in which the portions that define the coil width do not overlap or the area ratio of the overlapping portions is 50% or less It is a coreless motor characterized by being made.

  According to the first and second aspects of the present invention, since the overlapping of the winding portions of the adjacent coil segments that are parallel to each other can be suppressed, the current flowing in the direction of decreasing the torque can be suppressed and high efficiency can be obtained. In addition, the distance of the coil width grasped by the angle is defined as a range of angles when viewed from the axial direction of the rotation axis of the amateur. The same is true for other distances captured by angles. N is an odd number of 3 or more.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the coil segment has a substantially hexagonal shape at the inner opening. The shape of the opening inside the coil segment has a substantially hexagonal shape that can effectively use the straight portion.

  The invention according to claim 4 is the invention according to claim 3, wherein M is a natural number satisfying (2 ≦ M ≦ N−1), and the hexagonal openings in the direction in which the plurality of coil segments are adjacent to each other. The width of the part is 360 ° / N in angle, and the hexagonal opening in the Mth coil segment has the coil of the M−1th coil segment each having a width of 360 ° / 2N. A portion defining the width and a portion defining the coil width of the M + 1 th coil segment are located.

  The invention according to claim 5 is the invention according to any one of claims 1 to 4, wherein the coil segment is a multiple winding.

  The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the coil segment has a structure in which a plurality of coil windings are laminated.

  According to the present invention, the problem that a current flowing in a direction that generates torque in a direction opposite to the rotation direction of the motor flows in a part of the winding is improved, and a coreless motor having high efficiency is obtained.

It is a sectional side view of the coreless motor to which the invention is applied. It is a conceptual diagram which shows the process of manufacturing the amateur of embodiment stepwise. It is the conceptual diagram (A) which shows the state which expand | deployed the amateur of embodiment on the plane, and the conceptual diagram (B) which shows the state of the electric current seen from the axial direction. It is a conceptual diagram which shows the state of a connection. It is the conceptual diagram (A) which shows the state which expand | deployed the amateur of the comparative example on the plane, and the conceptual diagram (B) which shows the state of the electric current seen from the axial direction. It is a conceptual diagram which shows the state of the connection in another example. It is a conceptual diagram which shows the state of the connection in another example. It is a conceptual diagram of the coil segment of another example. It is a conceptual diagram which shows the state of the connection in another example.

(Overall structure)
FIG. 1 shows a coreless motor 100 to which the invention is applied. The coreless motor 100 is, for example, a coreless motor in which the number of poles of a rotor (amateur) is 3 and the magnetic pole is 2 poles. The coreless motor 100 includes a substantially cylindrical frame 101 that is an outer casing. One end of the frame 101 is a burring portion 102 having a reduced diameter, and a substantially cylindrical inner yoke 103 is fitted and fixed inside the burring portion 102. A bearing 104 is attached inside one end of the inner yoke 103, and the bearing 104 holds a shaft 105, which is a rotating shaft member, so as to be rotatable with respect to the inner yoke 103. In this example, the bearing 104 is a sliding bearing. A rolling bearing can also be used as the bearing 104. The same applies to the other bearing. Although the frame 101 and the inner yoke 103 are described separately, they may be formed integrally.

  A magnet 106 made of a permanent magnet is fixed to the outer periphery of the inner yoke 103. The magnet 106 has a substantially cylindrical shape, and is magnetized into two poles, an N pole and an S pole, along the circumferential direction. A bearing 107 is attached to the inside of the other end of the magnet 106, and the bearing 107 holds the shaft 105 in a rotatable state with respect to the magnet 106. The bearing 107 is described as being attached to the magnet 106, but may be attached to the inner yoke 103, the bracket 114, and the like.

  The shaft 105 is fixed to the rotation center of the amateur 116. The amateur 116 includes a commutator including a commutator base 108 and a commutator segment 111, and a coil forming assembly 109. That is, a substantially disc-shaped commutator base 108 is fixed to the shaft 105, and a coil forming assembly 109 formed in a substantially cylindrical shape is fixed to the outside of the commutator base 108. The coil forming assembly 109 has a structure in which a plurality of planar coils (coil segments) are stacked and then formed into a substantially cylindrical shape (curling).

  FIG. 2 (E) shows a state where the coil forming assembly 109 is developed on a plane. The coil forming assembly 109 includes coil segments 210, 220, and 230 processed into a planar shape. The coil segments 210, 220, and 230 are the same, and have an annular shape with a hexagonal opening on the inner side (center) in a state of being developed in a plane. Lead wires 211, 212, 221, 222, 232, and 232 from both ends of each of the coil segments 210, 220, and 230 are taps with twisted windings, and are drawn from the coil segments. Each coil segment is connected to lead wires 212, 221, 222, 231, 232, and 211, and the unfolded shape shown in FIG. 2 (E) is curled so that side a and side b are adjacent to each other. A cylindrical coil forming assembly 109 is configured. As shown in FIG. 1, a gap is secured between the coil forming assembly 109 and the magnet 106 so that the rotation of the armature 116 is not hindered.

  The dimensions of the portions indicated by the symbols α, α ′, β, β ′, γ, γ ′ in FIG. 2 in each coil segment are the coil width. The portions where the coil width is defined are portions where the windings extend in the axial direction in the state where the coil forming assembly 109 has a cylindrical shape. The coil width is a width dimension in the circumferential direction of one side of each coil segment adjacent in the circumferential direction (or partially adjacent to each other) in the state of the cylindrical coil forming assembly 109. The coil widths of the coil segments are all the same when viewed from the angle seen from the direction of the rotation axis, and in this case, they are in the range of 60 °. The distance between the center positions of adjacent commutator risers (eg, 111a and 111b) is 120 °, and the position where the lead wire of each coil segment comes out (position where the tap is taken out) and the commutator riser The distance is 30 °.

  The coil width of the coil segment is determined by a general formula (360 ° / (number of amateur poles × 2)). The distance between adjacent commutator risers is determined by (360 ° / number of amateur poles). The distance captured in the circumferential direction between the position where the lead wire of each coil segment is drawn (the position where the tap is drawn) and the commutator riser is obtained by (360 ° / (number of amateur poles × 4)). The error of these values is allowed to be in the range of about ± 50% or less, preferably in the range of about ± 10% or less, preferably about ± 5% or less.

  In this example, in adjacent coil segments, an overlap between winding portions extending in the same direction (portions where coil widths indicated by α, α ′, β, β ′, γ, and γ ′) are α is α. , Α ′, β, β ′, γ, γ ′, the positional relationship of the coil segments is determined so as to be 50% or less, preferably 10% or less, more preferably 5% or less. . For example, the overlap between the coil width α portion of the coil segment 210 and the coil width γ ′ portion of the coil segment 230 is set to be α / 2 or less. When this overlap exceeds 50%, the reduction in efficiency becomes significant. Note that the overlap of α, α ′, β, β ′, γ, and γ ′ is desirably as small as possible.

  As shown in FIG. 1, a resin commutator base 108 that supplies power to the coil forming assembly 109 is fixed to the shaft 105. The commutator base 108 is provided with three commutator segments 111 each of which is a metal piece insulated from each other to form a commutator. The three commutator segments are respectively commutator risers 111a and 111b. , 111c (see FIG. 2F).

  Lead wires 211 and 232 are connected to the commutator riser 111a, lead wires 212 and 221 are connected to the commutator riser 111b, and lead wires 222 and 231 are connected to the commutator riser 111c. FIG. 1 shows a state in which the lead wire 211 is connected to the commutator riser 111a.

  A brush 113 which is a power supply electrode on the stator side is in contact with the commutator segment 111 in a slidable state. The brush 113 is fixed to the bracket 114 and connected to the terminal plate 115 drawn out. Driving power is supplied to the terminal board 115 from the outside.

(Operation)
The amateur 116 includes a coil forming assembly 109, and the coil forming assembly 109 includes three coil segments 210, 220, and 230 (see FIG. 2E). Here, when a direct current is supplied to the terminal plate 115 as drive power, a current flows through the coil segments 210, 220, and 230 via the brush 113 and the commutator segment 111. At this time, the armature 116 starts to rotate due to the reaction between the magnetic field and the current by the magnet 106 (Fleming's left-hand rule). When rotating by a certain angle, the direction of current flowing through the three coil segments 210, 220, and 230 is sequentially switched by the rectifying action of the commutator segment 111, so that the amateur 116 continues to rotate.

(Amateur assembly process)
FIG. 2 shows a step-by-step process for manufacturing the coil forming assembly 109. First, as shown in FIG. 2A, a hexa-winding hexagonal jig 201 having a hexagonal cross section is prepared, and a magnet wire 202 is wound around the outer periphery thereof to create a solenoid coil having a hexagonal cross-sectional shape. For example, a self-bonding wire is used for the magnet wire 202. At the end of the winding start and end of winding to the hex winding jig 201, the magnet wire 202 is picked up and twisted to process the end into a ring shape to form a tap. By this operation, lead lines 211, 212, 221, 222, 231, 232 are formed. At this stage, each coil has a three-dimensional shape that is hexagonal when viewed from the axial direction. FIG. 2B shows the state of the coil viewed from the axial direction in this state.

  Next, in the case of a coil using a self-bonding wire, for example, a three-dimensional coil is crushed and pressed while being heated in the axial direction, and processed into a flat surface. At this process, it crushes in the state expanded to the left and right so that the shape of an inner part may become a hexagon, and the shape shown in FIG.2 (C) is obtained. FIG. 2C shows a coil segment 210 processed into a planar shape. Three coil segments are produced, and planar coil segments 210, 220, and 230 are produced. Then, these three coil segments 210, 220, and 230 are overlapped in the positional relationship shown in FIG. 2D and bonded and fixed together by bonding or the like to obtain the state shown in FIG. When the state shown in FIG. 2E is obtained, it is curled and fixed in a cylindrical shape by fixing with tape or adhesive, resin mold or the like. At this time, side a and side b, and side c and side d are adjacent to each other without a gap. Thus, the cylindrical coil forming assembly 109 shown in FIG. 1 is obtained.

  Referring to FIG. 2D, in the state of the coil forming assembly 109, the hexagonal opening 223 inside the coil segment 220 has a winding portion α on the right side of the coil segment 210 adjacent to the left side. The winding portion γ on the left side of the coil segment 230 adjacent to the right side is positioned. Here, the winding portions α, α ′, β, β ′, γ, and γ ′ in which the coil segments are arranged in the adjacent direction are mutually parallel winding portions in which the windings extend in the same direction. The width of the hexagonal opening 223 inside 220 in the direction in which the coil segments are adjacent to each other is 120 ° in terms of angle, and the coil widths of the winding portions α ′ and γ of the coil segments 210 and 230 located there are 120 °. Are both 60 °.

  That is, when attention is paid to winding portions parallel to each other in a plurality of coil segments adjacent in the circumferential direction, the coil width of the M-1th coil segment is defined inside the Mth coil segment. Winding portion A and winding portion B, which is a portion in which the coil width of the (M + 1) th coil segment is defined, are located. Here, if the number of poles of the amateur is N, the width in the circumferential direction inside the coil segment where the winding portions A and B are located is 360 ° / N in terms of an angle. The width (coil width) is 360 degrees / 2N, respectively. In an ideal state, an opening portion with a width of 360 ° / N inside the M-th coil segment is formed by winding portions A and B (with a coil width of 360 ° / 2N) of the coil segment width 360 ° / 2N adjacent to both sides. Filled with specified part). In this state, parallel windings of the coil segments exist continuously without any gap along the circumferential direction, and the winding portions of the coil segments have a positional relationship that does not overlap. Here, M is a natural number satisfying 2 ≦ M ≦ N−1.

  Once the coil forming assembly 109 is obtained, it is fixed to the commutator base 108 using, for example, an adhesive, the ends of the lead wires 211 and 232 are connected to the commutator riser 111a, and the end portions of the lead wires 212 and 221 are connected. Is connected to the commutator riser 111b, and the ends of the lead wires 222 and 231 are connected to the commutator riser 111c. In this way, as shown in FIG. 2F, an armature 116 in which the commutator segment 111 and the coil forming assembly 109 are connected is obtained.

(Principle for high efficiency)
For example, the β and α ′ portions are adjacent to each other, but at a certain moment, the directions of the currents flowing through the β portion and the α ′ portion are reversed. At this time, in the part where the part of β and the part of α ′ overlap, the other current becomes the current in the direction in which the reverse torque is generated with respect to one current. In other words, the current flows in the opposite direction between the two, thereby canceling the generated magnetic flux and reducing the magnetic flux contributing to the generation of torque. Therefore, when the ratio of the area of the overlapping portion is increased, the obtained torque is reduced even when the same drive current is supplied. That is, efficiency is reduced.

  FIG. 3A shows a state in which the coil forming assembly 109 is developed on a plane, and FIG. 3B shows a state of current as viewed from the axial direction. FIG. 4 shows the state of connection as viewed from the axial direction. FIG. 5A shows a state in which an armature coil according to the prior art is developed on a plane, and FIG. 5B shows a state of current as viewed from the axial direction.

  As can be seen from a comparison between FIG. 3 and FIG. 5, when the present invention is used, the presence of a current flowing in the reverse direction that causes the above-described torque reduction can be suppressed. That is, in the case of FIG. 5, the portion of the winding surrounded by reference numerals 51 to 54 is a portion that generates torque in the direction opposite to the motor rotation direction with respect to the magnetic pole (S or N pole) of the stator side magnet. Incurs a decrease in efficiency. On the other hand, in the case of FIG. 3, since there is no portion corresponding to the reference numerals 51 to 54 of FIG. 5, the efficiency reduction that occurs in the case of FIG. 5 does not occur.

(Optimal range)
Overlap of winding portions extending in the same direction between adjacent coil segments can be allowed to some extent. Hereinafter, this point will be described. For example, although the portion α and the portion β ′ in FIG. 2 are adjacent to each other, if they are partially overlapped, the central portion faces the boundary portion of the magnetic pole of the magnet 106 on the rotor side. Therefore, this central portion does not contribute to generation of torque that rotates the rotor 116. On the other hand, as the area in the circumferential direction of the portion where the α portion and β ′ portion overlap increases, the tendency to generate reverse torque that contributes to the rotation of the rotor 116 gradually increases, and the efficiency increases accordingly. Decrease gradually. In order to suppress this decrease in efficiency, the ratio of the portion where α portion and β ′ portion overlap is 50% or less, preferably 10%, relative to the area of α and β ′ (or distance in the circumferential direction) Hereinafter, it is more preferably 5% or less.

(Superiority)
In comparison with the same number of amateur poles, the motor can be made more efficient than the conventional structure. For example, when the number of poles of the amateur is three, the maximum efficiency value (calculated value) of the conventional winding structure is 66.7%, whereas when the present invention is used (coreless motor 100), A maximum efficiency value (calculated value) of 88.7% is obtained. When the number of amateur poles is 5, the maximum efficiency value (calculated value) of the conventional structure is 80%, whereas when the present invention is used, the maximum efficiency value of 95.4% is obtained. can get. Here, the maximum efficiency value is a parameter indicating the ratio of the current that contributes to the rotation of the motor out of the total current flowing through the winding. The maximum efficiency value is the maximum efficiency in the structure, and no efficiency beyond that value is theoretically obtained. Actually, the actual motor efficiency is obtained by subtracting various losses therefrom.

  In the conventional winding structure, methods for increasing the number of amateur poles (7 poles, 9 poles, 11 poles) are known in order to improve the maximum efficiency value of the motor. However, generally, when the number of amateur poles increases, the process becomes complicated in terms of processing of commutators and the like, which is disadvantageous in terms of cost and yield. In addition, when it is desired to reduce the size of the motor, this point becomes more disadvantageous, causing a problem in feasibility. On the other hand, when the present invention is used, even with a small number of amateur poles such as three poles and five poles, high efficiency can be obtained as compared with the conventional structure. Therefore, the process is simplified in terms of processing such as a commutator, which is advantageous in terms of cost, yield, and the like. In addition, it is highly feasible in terms of application to a small motor.

  In addition, when the single winding is used, the overlapping of the windings is reduced as compared with the existing structure, so that the amateur can be thinned. Since the amateur can be made thinner, the gap between the magnet and the magnetic circuit can be reduced, and high torque characteristics can be expected. Moreover, since the amateur weight can be reduced, the response can be speeded up.

  In addition, since there is no bias in the weight balance within the circumference of the amateur as compared with the existing structure, motor vibration can be reduced by improving the amateur weight balance.

(Other examples)
FIG. 6 shows an example in which the number of amateur poles is five. In this case, the width of the coil segment is 36 ° from the general formula of (360 ° / (number of amateur poles × 2)). The distance between the position where the lead wire of each coil segment is drawn (the position where the tap is drawn) and the commutator riser is 18 ° from (360 ° / (number of amateur poles × 4)).

  FIG. 7 shows an example in which the number of amateur poles is seven. In this case, the width of the coil segment is 25.71 °. The distance between the position where the lead wire of each coil segment is drawn (the position where the tap is drawn) and the commutator riser is 12.86 °.

  FIG. 8 shows an example in which the coil segments 210, 220, and 230 in a state before being crushed are multiple windings (for example, double windings). By using multiple windings, it is possible to increase the winding line factor.

  FIG. 9 shows another example in which the line factor is increased. In this example, using the technique described in Japanese Patent Laid-Open No. 5-30721, the structure shown in FIG. 4 is used as a basic form, and two of them are used to form a multilayer. In this case, the connection between coil segments is performed using a relay terminal. The structure on the stator side is the same as that of the coreless motor 100 of FIG.

  In the above illustration, the example of the coreless motor 100 has been shown, but the present invention can also be applied to a motor in which the rotor rotates inside the stator. The aspect of the present invention is not limited to the individual embodiments described above, and includes various modifications that can be conceived by those skilled in the art, and the effects of the present invention are not limited to the contents described above. That is, various additions, modifications, and partial deletions can be made without departing from the concept and spirit of the present invention derived from the contents defined in the claims and equivalents thereof.

  The present invention can be used for a coreless motor.

DESCRIPTION OF SYMBOLS 100 ... Coreless motor, 101 ... Frame, 102 ... Burring part, 103 ... Inner yoke, 104 ... Bearing, 105 ... Shaft, 106 ... Magnet, 107 ... Bearing, 108 ... Commutator base, 109 ... Coil molding assembly, 111 ... Commutator segment, 111a ... Commutator riser, 111b ... Commutator riser, 111c ... Commutator riser, 113 ... Brush, 114 ... Bracket, 115 ... Terminal board, 201 ... Hex winding jig, 202 ... Magnet wire, 210 ... Coil segment (processed into a planar shape), 211 ... Lead wire (tap), 212 ... Lead wire (tap), 220 ... Coil segment (processed into a planar shape), 221 ... Lead wire (tap), 222 ... lead wire (tap), 223 ... opening, 230 ... coil seg (processed into a planar shape) Cement, 231 ... lead wire (tap), 232 ... lead wire (taps).

Claims (6)

It has an amateur composed of multiple coil segments,
The coil width of the plurality of coil segments is (360 ° / 2N) as an angle, where N is the number of poles of the armature,
Both ends of the plurality of coil segments are respectively connected to the commutator riser from angular positions shifted by (360 ° / 4N) with respect to the commutator riser. It has an amateur composed of multiple coil segments,
The coil width of the plurality of coil segments is (360 ° / 2N) as an angle, where N is the number of poles of the armature,
The plurality of coil segments have a structure in which a polygonal cylindrical coil is crushed in the axial direction and processed into a planar shape,
The amateur has a structure in which the plurality of coil segments are arranged along a cylindrical surface,
In the thickness direction of the amateur, coil segments adjacent in the circumferential direction are arranged in a state where the portions defining the coil width do not overlap, or in a state where the area ratio of the overlapping portions is 50% or less. Features a coreless motor.   3. The coreless motor according to claim 1, wherein the coil segment has a substantially hexagonal shape in a portion of an inner opening. 4. M is a natural number satisfying (2 ≦ M ≦ N−1),
The width of the hexagonal opening portion in the direction in which the plurality of coil segments are adjacent is 360 ° / N in terms of angle,
The hexagonal opening in the Mth coil segment has a portion defining the coil width of the M−1th coil segment having a width of 360 ° / 2N and the coil width of the M + 1th coil segment, respectively. The coreless motor according to claim 3, wherein the defined portion is located.   The coreless motor according to any one of claims 1 to 4, wherein the coil segment is a multiple winding.   The coreless motor according to claim 1, wherein the coil segment has a structure in which a plurality of coil windings are stacked.

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