Rotary electric machine, method of manufacturing stator in rotary electric machine, and control system for rotary electric machine

Abstract

To construct a stator coil of a rotary electric machine such that it can be easily assembled in coaxial winding.SOLUTION: A stator coil is constructed by inserting and connecting coil pieces 10, 11, 20.21, 30, and 31 in a hair pin shape formed from rectangular wire from one side and the other side in the axis direction. A length of a straight part of each coil piece is a half of the shaft length of the stator core. Both leg end parts are convex- shaped or concave shaped such that a convex part and a concave part are fitted to each other. A space between slots is constructed by three types of coil pieces: center coil pieces 10 and 11 connecting each slot at a center in a radial direction in a circumferential direction; inner coil pieces 20 and 21 connecting a coil end part in the circumferential direction while being deviated to an inner side in the radial direction from the radial position of the slot; and outer coil pieces 30 and 31 connecting them in the circumferential direction while being deviated to the outer side in the radial direction. Lengths of the coaxial coil parts formed of the center coil pieces 10 and 11c, the coil pieces 20 and 31, and the coil pieces 30 and 21 connected are made equal to uniform a resistance value and increase assemblability.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a rotating electrical machine having a stator structure in which stator coils of a radial-gap type rotating electrical machine are concentrically wound with coils having different coil end shapes for each phase, and the electrical resistance values can be made the same for each phase, a method for manufacturing the stator of the rotating electrical machine, and a control system for the rotating electrical machine.

Background Art

[0002] Rotating electrical machines (motors) used as power sources for industrial machines and for driving automobiles are required to have higher efficiency. In order to improve the efficiency of a rotating electrical machine, it is necessary to reduce the losses of the rotating electrical machine. A general design method is to consider a reduction design for coil copper loss and core iron loss, which are two major factors of the losses of the rotating electrical machine. When the output characteristics (rotational speed and torque) of the required specifications of the rotating electrical machine are determined, the mechanical loss is uniquely determined, so a design for reducing the iron loss and copper loss becomes important. The iron loss can be reduced depending on the soft magnetic material used. In general rotating electrical machines, electromagnetic steel sheets are used for the core part, and those having different loss levels depending on the thickness and Si content are used. There are high-functional materials such as iron-based amorphous metals, fine metals, and nanocrystalline materials that have a higher magnetic permeability and lower iron loss than electromagnetic steel sheets, but in these material systems, the plate thickness is very thin at 0.025 mm, and the hardness is 900 in Vickers hardness, which is more than five times that of electromagnetic steel sheets. Since there are many problems in manufacturing a rotating electrical machine at low cost, these high-functional materials cannot be applied to rotating electrical machines.

[0003] Since the copper loss is mainly determined by the relationship between the resistance value of the coil and the current, measures such as reducing the coil resistance value by cooling and reducing the current value by suppressing the decrease in the residual magnetic flux density of the magnet are taken. In recent years, in motors for automotive drive and the like, designs have been made to increase the ratio (occupancy ratio) of the conductor to the cross-sectional area of the stator slot to minimize the resistance value up to the theoretical limit. However, a coil using a rectangular wire that can have a high occupancy ratio in the slot has a complex structure for routing the coil end portions extending outward from both ends of the slot, and by connecting these conductors to each other by a method such as welding, there are problems such as an increase in the volume (wire length) of the coil end portion and a slightly increased resistance value.

[0004] In Patent Document 1, a technique is disclosed in which a two-legged hairpin-shaped conductor segment is inserted into the stator coil of a motor, and each is bent and formed at the coil end portion on the side opposite to the inserted side, and welded to the bent conductor of another hairpin-shaped coil arranged in the circumferential direction to form an annular coil. This method has the effect of increasing the slot occupancy ratio, but on the other hand, during manufacturing, since it is necessary to bend and form a thick and hard rectangular conductor, there may be stress on the stator core, damage to the slot insulator, residual stress remaining at the connection portion when bent, and it may be difficult to ensure the reliability of the welded joint, leaving room for improvement as a manufacturing method. Also, since a space around the welded portion must be secured for welding, there is a problem that the coil end portion becomes large on the welding side.

[0005] The technique of Patent Document 2 is known as a method for attempting to improve those problems. Patent Document 2 shows a method of mechanically and firmly joining the tip shape of the coil as a press fit tolerance. Also, in Patent Document 2, by using a resin bobbin and joining the uneven tip portions by applying stress in a state where the insertion region of the coil is firmly secured, a highly reliable connection becomes possible.

[0006] The stator structures using straight angle wires shown in Patent Documents 1 and 2 adopt a winding structure called wave winding. The reason for this is that since the coil shapes are the same in the circumferential direction, it becomes a structure in which the formation of hairpin-shaped coils, and twisting and welding after insertion can be easily performed. In the wave winding structure, since all the coils are connected in the circumferential direction, the number of coils per phase becomes the same as the number of coils per pole per phase slot. For this reason, there is a drawback that the degree of design freedom is low, such as the need to increase the number of slots when increasing the number of parallel coils. In terms of the degree of design freedom, in wave winding, it is necessary to make the number of turns per slot an even number, and when the number of slots per pole per phase is 2, two coils of System 1 and System 2 are formed. However, since the coils of System 1 and System 2 are alternately and evenly arranged in the same slots, the magnetic interference between the two coils becomes large. This magnetic interference may affect the induced electromotive force of each other due to a deviation in the current application timing, etc., and may disturb the current waveform when trying to independently control and drive the two coils.

[0007] In order to solve the above problems, a concentric winding coil configuration can be considered. When manufacturing a general rotating electrical machine, a concentric winding stator is manufactured by a method in which a plurality of thin round wires bundled together are wound to form a coil, and the coil is inserted into the stator slots using a device called an inserter. In this way, a method of assembling a wound coil with its shape adjusted in advance to the stator core is shown in Patent Document 3.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0009] In the manufacturing method according to the technique disclosed in Patent Document 3, since the coil is assembled in the axial direction or in the direction from the inner diameter to the outer circumference of a semi-closed slot in which the tips of the teeth are flange-shaped, there is a problem that the ratio of the conductor cross-section in the cross-sectional area of the slot, that is, the space factor, cannot be increased. Further, since the shape of the coil end is different for each phase depending on the insertion order, it is difficult to make the resistance value and inductance value of the coil uniform.

[0010] The present invention has been made in view of the above background, and its object is to increase the space factor in the slot by combining hairpin-shaped conductors (coil pieces) using flat wires for the concentric wound stator of a rotating electrical machine, and to make the coil end shapes of the coils of each phase have a shape without interference with each other's phases, and to make the coil lengths of each layer of the coil the same so that the coil resistance and coil inductance can be made the same. Another object is to provide a rotating electrical machine with improved assemblability of the stator coil.

Means for Solving the Problems

[0011] The features of the present invention for solving the above problems are as follows, for example. According to one feature of the present invention, the shape of the stator coil of a distributed winding radial gap type rotating electrical machine is made into a shape that connects between slots for realizing a concentric winding structure by using a hairpin shape formed by a flat wire or a U-shaped coil piece. The length of the straight portion (linear portion) of the coil piece is set to approximately half of the axial length of the stator core, and convex or concave shapes that can be fitted to each other are formed at both end portions of the coil piece. The coil end shapes for each phase of the coil pieces for constituting the concentric winding are different for each phase, and there are three types: a structure in which the connection between slots is such that the radial positions (insertion holes) of the slots are in the same position or shifted by one insertion hole and connected in the circumferential direction (central coil piece), a shape in which the coil end portion is connected in the circumferential direction by avoiding the radial direction inside the radial position of the slot (inner coil piece), and a shape in which the coil end portion is connected in the circumferential direction by avoiding the radial direction outside the radial position of the slot (outer coil piece). At this time, since the outer diameter of the coil connected by the outer side in the radial direction is larger and the coil end length becomes longer than that of the coil connected by the inner side in the radial direction, the perimeter of the coil becomes longer and the resistance value increases. In order to balance this, the coil on one axial side is connected as an inner arranged coil end, and the other axial coil is connected as an outer arranged coil end. Thereby, the difference in the coil perimeter between the inner coil piece and the outer coil piece is eliminated, and the coil resistance value can be balanced. The central coil connected in the circumferential direction near the approximate center in the radial direction within the slot is designed so as to be the same as the perimeter of the coil formed by connecting the inner coil piece and the outer coil piece, that is, the resistance values are matched. As a result, although it is a concentric winding formed using a flat conductor, the resistance value and inductance of the coil can be made uniform.

[0012] According to another feature of the present invention, the coil piece is formed by a rectangular wire, and has two straight portions that become portions accommodated in circumferentially spaced slots, and coil end portions that are formed to extend outward in the direction of the rotation axis from the straight portions and connect the two straight portions. The coil end portion is formed by two extension portions that extend outward in the direction of the rotation axis from the straight portion of the coil piece and a connection portion that circumferentially connects the ends of the extension portions. After the stator coil is connected, the connection portions of the central coil pieces are arranged to be aligned in the radial direction, and by providing an angle such that the extension portions of the inner coil pieces bend radially inward, the connection portions of the inner coil pieces are arranged to be laminated in the rotation axis direction at a radially inner portion than the laminated portion of the central coil pieces, and by providing an angle such that the extension portions of the outer coil pieces bend radially outward, the connection portions of the outer coil pieces are arranged to be laminated in the rotation axis direction at a radially outer portion than the laminated portion of the connection portions of the central coil pieces. The angle of the bending portion of the extension portion toward the inner side with respect to the straight portion of the inner coil piece is an angle greater than 0 degrees and 45 degrees or less, and the angle of the bending portion of the extension portion toward the outer side with respect to the straight portion of the outer coil piece is preferably an angle greater than 0 degrees and 45 degrees or less. With such shapes of the inner coil piece and the outer coil piece, when inserting the coil pieces into the slots of the stator core from both sides in the rotation axis direction, the central coil piece, the inner coil piece, and the outer coil piece can be inserted and assembled in parallel in the rotation axis direction one by one in order.

[0013] According to still another feature of the present invention, the stator core is composed of a core back core and a plurality of tooth cores combined with the core back core. A low-loss soft magnetic material is used as the tooth core, and resin bobbins for accommodating a plurality of rectangular wires in the radial direction are respectively arranged in the slots between adjacent tooth cores. Further, in order to improve the assemblability, it is preferable to form the stator core in a two-divided shape in the rotation axis direction.

Effects of the Invention

[0014] By adopting the coil configuration as described above, a concentric-wound coil with a high conductor occupancy rate and little variation in coil resistance between phases can be formed. As a result, motor design and system design that take advantage of the characteristics of the concentric-wound coil configuration become possible. In addition, since the number of coils can be set regardless of the number of slots per pole per phase, the degrees of freedom of series and parallel circuits increase, and design changes in response to voltage specifications and differences in frequency (rotational speed, torque) can be easily realized. That is, in the case of concentric winding, since the number of turns per slot, which cannot be configured in wave winding, can be designed to be odd, the degree of freedom in design for coping with the above-mentioned specification changes can be increased. Furthermore, since the coils have an independent structure between systems, magnetic interference can be reduced, and thus there are fewer restrictions on the number of drive circuits to be used. Moreover, when assembling the stator coil with the concave-convex fitting, by making the insertion order of the coils appropriate, assembly can be performed while performing the concave-convex fitting process simultaneously with the insertion, so that the assemblability of the coils is greatly improved.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Embodiments for Carrying Out the Invention

[0016] Hereinafter, embodiments of the rotating electric machine 1 of the present invention will be described with reference to the drawings and the like. The following description shows specific examples of the content of the present invention, and the present invention is not limited to these descriptions, and various changes and modifications by those skilled in the art are possible within the scope of the technical idea disclosed in this specification. Also, in all the drawings for explaining the present invention, those having the same function are denoted by the same reference numerals, and the repeated description thereof may be omitted.

[0017] The rotating electrical machine 1 of this embodiment is used for driving various devices. FIG. 17 shows an example thereof, and shows a screw-type air compressor 100 driven by the rotating electrical machine 1. The air compressor 100 includes a rotating electrical machine 1 that supplies rotational power, and an air end 101 that creates compressed air using the rotational force of the rotating electrical machine 1. The rotating electrical machine 1 is a so-called embedded magnet synchronous motor, and houses a rotor 6 and a stator 2 in a housing 4. The housing 4 is composed of a cylindrical body portion 4a having openings on the front side and the rear side, a front end bracket 4b attached to the front opening of the body portion 4a, and a rear end bracket 4c attached to the rear opening of the body portion 4a. A through hole is formed in the front end bracket 4b, and one end side of the rotating shaft 5 to which the rotor 6 is fixed protrudes from the inside of the housing 4 toward the outside of the front side. The stator 2 is formed with a stator core 3 and a stator coil 9 wound around the stator core 3. In FIG. 17, the end core portion shape of the stator coil 9 is schematically shown, and the detailed shape is the shape shown in FIGS. 1 to 5 described later.

[0018] The M rotor 120 of the air end 101 is connected to the rotating shaft 5 of the rotating electrical machine 1 by connecting means (for example, spline, coupling, gear, etc.), and supplies the rotational power of the rotating electrical machine 1 to the first shaft 105 of the air end 101. Here, the rotating shaft 5 and the first shaft 105 are directly connected, and their rotation axis is Ax. A first bevel gear 110 is provided at the tip of the first shaft 105. The bevel gear 110 rotates the adjacent second bevel gear 130 in the opposite direction at the same speed by meshing with the second bevel gear 130. Since the second bevel gear 130 is provided at the tip of the second shaft 135, the F rotor 140 fixed to the second shaft 135 rotates in the opposite direction and at the same speed as the M rotor 120 fixed to the first shaft 105 due to the rotation of the second bevel gear 130.

[0019] As the rotating electrical machine 1 rotates, the M rotor 120 and the F rotor 140 rotate, and air is sucked in from the suction port of the M rotor 120 (not visible in the figure). Further, when the M rotor 120 and the F rotor 140 rotate, the meshing of the tooth profiles of each rotor disengages, and air is sucked into the entire tooth profile space. Further, when the M rotor 120 and the F rotor 140 rotate and air blocks the wall of the casing 102, the suction is completed. The air trapped between the tooth profile space and the casing is compressed by the meshing of the rotors 120 and 140. Thus, as the rotors 120 and 140 rotate, the air moves axially while being further compressed between the tooth profile space 145 and the casing 102, reaches the discharge port (not visible in the figure), and reaches a predetermined pressure. The compressed air is discharged from the discharge port on the discharge side opened in the casing 102.

[0020] FIG. 1A is a partial perspective view of the stator 2 of the rotating electrical machine 1 according to an embodiment of the present invention. The rotating electrical machine 1 of this embodiment is a radial gap type, and a rectangular conductor (hereinafter referred to as a "rectangular wire") is used for the coil of the stator 2, and the stator coil 9 is formed by concentric winding. In FIG. 1A, the coil shape of three phases for one pole of the stator coil 9 is partially shown.

[0021] The stator 2 has a total of 48 slots and 8 rotor poles. The coil pieces 10, 11, 20, 21, 30, 31, 41 to 46 arranged in each slot have a rectangular flat wire cross-sectional shape. Here, the stator 2 is configured to be divided into two parts in the direction of the rotation axis Ax, that is, it is divided into a lead-out side 2a and a non-lead-out side 2b. On the lead-out side stator 2a of the stator coil 9, a plurality of coil pieces (10, 20, 30) connecting between the slots and a plurality of lead-out pieces 41 to 46 drawn out for the connection of the stator coil 9 are used. On the non-lead-out side 2b, a plurality of coil pieces (11, 21, 31) connecting between the slots of the stator core 3 are used. The coil pieces (10, 20, 30) with a structure connecting the slots of the stator core 3 on the lead-out side 2a in the circumferential direction of the slots and the coil pieces (11, 21, 31) with a structure connecting the slots of the stator core 3 on the non-lead-out side 3a at the same diameter as the radial position of the slot 3c in the circumferential direction are combined to form a concentric winding coil (this is called a U-phase coil).

[0022] Here, the detailed shape of the stator core 3 will be described with reference to FIGS. 2A to 2E. FIG. 2A is a perspective view of the stator core 3 alone on the lead-out side 2a, showing a state in which the bobbin 65 is mounted but the stator coil 9 is not wound. FIG. 2B is a partially enlarged view seen from one side (lead-out side) in the direction of the rotation axis of FIG. 2A (however, the bobbin 65 is not mounted). As shown in FIGS. 2A and 2B, the stator core 3 has a core back core 3a formed on the outer peripheral side, and a total of 48 slots 3c are formed in the circumferential direction by arranging tooth cores 3b formed by cutting an amorphous metal foil strip into a trapezoidal shape and laminating them on the tooth portions. In the rotating electrical machine 1 that rotates at high speed, the frequency of the supplied voltage is high, and the iron loss in the tooth portions becomes large. Therefore, it is desirable to configure it using a low-loss non-magnetic material. In this embodiment, the tooth portions are manufactured from a material different from the material (electromagnetic steel sheet) of the core back core 3a portion. Incidentally, instead of amorphous, the tooth portions may be constituted by Finemet, which is a nanocrystalline alloy material, or a nanocrystalline alloy with high saturation magnetization. Also, when the tooth portions are manufactured from the same material as the core back core 3a using an electromagnetic steel sheet, using a low-iron-loss material such as a 6.5% Si-containing steel sheet for thin plates can also be said to be a measure for improving characteristics.

[0023] As shown in FIG. 2B, the stator core 3 is constituted by combining tooth cores 3b having a trapezoidal cross-sectional shape orthogonal to the rotation axis, and a core back core 3a for holding them is made of an electromagnetic steel sheet. Since the magnetic flux density in the core back portion is relatively low compared to the tooth portions and the influence of harmonics is small, it is sufficient to use a material with relatively low loss. This structure is partly due to the fact that the shape of the core back core 3a is designed with a trapezoidal cross-sectional shape that can be formed only by cutting because it is difficult to punch amorphous into a complex shape. A resin bobbin 65 for insulation is assembled in accordance with this combined core shape. FIG. 2C is a perspective view seen from the inner peripheral side of the bobbin 65, and FIG. 2D is a perspective view seen from the outer peripheral side of the bobbin 65.

[0024] The bobbin 65 is formed to have a length substantially the same as the length of the stator 2 in the axial direction of the rotation axis (for each of the lead-out side 2a and the non-lead-out side 2b) (strictly speaking, the bobbin 65 is longer by the amount of the jaw portions 67 and 68), and is formed to have the same width as the width of the slot 3c when viewed in the circumferential direction. Inside the bobbin 65, m (here, m = 4) insertion holes 66a to 66d for inserting a flat conductor in a direction parallel to the axial direction of the rotation axis are formed from the inner side to the outer side in the radial direction. Partition walls are provided at the boundary portions of the insertion holes 66a to 66d, respectively, and the structure is such that each coil piece can be surely insulated individually. At both axial ends of the bobbin 65, flange portions 67 and 68 are provided, and they also have the function of axially holding the end faces of the tooth cores 3b. On the inner circumferential sides of the jaw portions 67 and 68, claw portions 67a and 68a with contour portions protruding in a claw shape are respectively formed, and the bobbin 65 is assembled so as to be inserted from the inner side to the outer side in the radial direction of the stator core 3. At this time, the claw portions 67a and 68a are fitted into recesses 3d that are continuous in the axial direction of the rotation axis and are formed on the inner circumferential side of the core back core 3a. In a state where all the bobbins 65 are assembled in the slots 3c of the stator core 3, the structure is such that the tooth cores 3b are axially restrained in addition to being applied in the circumferential direction. FIG. 2E is a view showing the state in which the bobbin 65 is attached from the state of FIG. 2B.

[0025] Returning to FIG. 1 again. Between the slots 3c of the stator 2 on the lead-out side 2a, an inner coil piece 20 having a shape in which coil ends are arranged and connected inside the slots in a direction more inward than the radial direction in which the conductor enters the slots, and an outer coil piece 31 having a structure in which between the slots of the stator 2 on the non-lead-out side 2b and between the slots are connected outside the radial position of the conductor are combined to form a concentric wound coil (hereinafter, the coil having this structure is referred to as a V-phase coil).

[0026] Furthermore, an outer coil piece 30 having a shape in which coil ends are arranged and connected outside the slots in a direction more outward than the radial position in which the conductor enters the slots between the slots of the stator 2 on the lead-out side 2a, and an inner coil piece 21 having a structure in which between the slots of the non-lead-out side stator 2b and between the slots are connected inside the radial position of the conductor are combined to form a concentric wound coil (hereinafter, the coil having this structure is referred to as a W-phase coil).

[0027] As described above, since the coil ends (coil pieces 20 and 21) passing through the inner peripheral side are shorter in length than the coil ends (coil pieces 30 and 31) passing through the outer peripheral side, when connecting the coils, the outer coil piece 30 on the outer peripheral side and the inner coil piece 21 are combined. Similarly, the outer coil piece 31 on the outer peripheral side and the inner coil piece 20 are combined, and the lengths of these coils are made the same as the lengths by the central coil pieces 10 and 11, so that the coils of the U-phase, V-phase, and W-phase are configured. Thus, it is possible to prevent a difference in resistance value from occurring among the U-phase, V-phase, and W-phase. Further, the portions (coil end portions) of the coil pieces 20 and 21 exposed from the stator core 3 are inclined toward the inner peripheral side, and the wiring is performed in such a way that the coil end portions are laminated in the axial direction of the rotation axis. The portions (coil end portions) of the coil pieces 30 and 31 exposed from the stator core 3 are inclined toward the outer peripheral side, and the coil end portions are laminated in the axial direction of the rotation axis. Therefore, when inserting each coil piece (10, 11, 20, 21, 30, 31) and the lead-out pieces 41 to 46 into the slots 3c from both sides of the stator core 3 in the axial direction, there is an advantage that the stator coil 9 can be assembled by inserting all the coil pieces in parallel in the axial direction in order.

[0028] As shown in the projection views of FIGS. 1B and 1C, when the coil pieces 10 and 11 having a structure connecting between two slots in the circumferential direction with the same diameter as the radial position of the slot are arranged, the coil coming out from the slot in the portion hidden by the coil needs to be connected to the other through a route passing through either the inner peripheral side or the outer peripheral side. And even when they are arranged in the circumferential direction at every 180 degrees in the electrical angle, it is necessary to have a shape without interference. In FIGS. 1A to 1C, only one pole portion of the formed coils is shown, but this structure is repeated at an electrical angle of 180 degrees (mechanical angle of 45 degrees), and the coil pieces are arranged in all the slots in the circumferential direction, whereby the stator coil 9 of the rotating electrical machine 1 is completed.

[0029] Figures 3A to 3E are diagrams for explaining the structure of the opposite-side exit side 2b of the stator 2 shown in FIG. 1. FIG. 3A shows a drawing obtained by projecting a part of the stator coil 9 on the opposite-side exit side 2b in the axial direction from the arrow 70 side in FIG. 1, and FIG. 3B is a perspective view from the inner peripheral side. Note that the illustrated objects of the coil pieces 11 and the coil 21 shown in FIGS. 3A and 3B do not match the view seen from the direction of the arrow 70 in FIG. 1A. The central coil piece 11 where the coil ends are arranged with the same diameter as the conductor insertion position of the slot 3c is arranged in such a way that four types of coil pieces 11 with different sizes in the radial direction are connected from one of the four slot insertion holes 66a to 66d of the bobbin 65 to four insertion holes separated by five slots in the circumferential direction. At this time, the numbers of the insertion holes 66a to 66d counted from the inner peripheral side where one end and the other end of the coil piece 11 are inserted are the same. For this reason, four types of coil pieces 11 with different sizes are prepared.

[0030] FIG. 3C shows a perspective view of the shape of the central coil piece 11. The coil piece 11 is a conductor obtained by baking and coating an insulating enamel on a soft copper wire with a square cross-section. The coil piece 11 includes straight portions 11a and 11e that are formed linearly in the portion accommodated in the slot 3c, extension portions 11b and 11d that are respectively connected to the straight portions 11a and 11e and extend outward in the axial direction of the rotation axis from the slot 3c, and connecting portions 11c that connect between the end portions separated from the connection portion between the extension portions 11b and 11d. The coil piece 11 formed by the portions 11a to 11e is formed by bending a flat angle line into a substantially U shape like a so-called hairpin. Here, in relation to the overall arrangement space of the stator coil 9, in order to secure the region of the inner peripheral side portion of the coil piece 11 rather than the connection portion 11c, the extension portions 11b and 11d of the coil piece 11 are preferably configured to be bent outward in the radial direction by an angle θ 4 (however, θ 4 should be less than a dozen degrees). Also, the bending R (radius of curvature) of the connection portion between the extension portion 11b and the connection portion 11c is formed to be relatively small so as not to interfere with other coil pieces. Similarly, the bending R (radius of curvature) of the connection portion between the extension portion 11d and the connection portion 11c is also formed to be relatively small.

[0031] The end legs of the central coil piece 11 are shaped like recesses 11f and 11g. This shape is formed by punching out the concave inner peripheral part with a press or the like, and the cut cross-sectional part forms a plating layer with a thickness of about 10 μm by electrolytic tin plating. Since the outer skin part of the coil piece 11 has an enamel cortex, no plating layer is formed, so the plating layer is formed on the cut surface part. As shown in Fig. 3B, a part of the coil ends of the inner coil piece 21 (extension parts 21b and 21d) is arranged so as to partially overlap in the rotation axis direction with the radially inner part of the connection part 11c of the central coil piece 11. Similarly, a part of the coil ends of the outer coil piece 31 (extension parts 31b and 31d) is arranged so as to partially overlap in the rotation axis direction.

[0032] The inner coil piece 21 is formed in a substantially U shape, and is formed by straight portions 21a and 21e formed linearly, extension parts 21b and 21d extending radially inward by an angle θ with respect to the straight portions 21a and 21e, and a connection part 21c connecting the axially separated ends between the extension parts 21b and 21d. The extension parts 21b and 21d of the coil piece 21 are bent radially inward by an angle θ with respect to the straight portions 21a and 21e. Also, due to the relationship of the overall arrangement space of the stator coil 9, in order to secure the installation area of the inner peripheral side part of the coil piece 21 with respect to the connection part 21c, and also, the bending radius R of the connection part between the extension part 21b and the connection part 21c and the bending radius R of the connection part between the extension part 21d and the connection part 21c need to be made relatively small so as not to interfere with other coil pieces. 5

[0033] The outer coil piece 31 is formed in a substantially U shape, and is formed by straight portions 31a and 31e formed linearly, extension parts 31b and 31d extending radially inward by an angle θ with respect to the straight portions 31a and 31e, and a connection part 31c connecting the axially separated ends between the extension parts 11b and 11d. The extension parts 31b and 31d of the coil piece 31 are bent radially inward by an angle θ with respect to the straight portions 31a and 31e. 6It is only bent radially outward. Also, due to the relationship of the overall arrangement space of the stator coil 9, in order to secure the installation area of the outer peripheral side portion rather than the connection portion 31c of the coil piece 31, and also, the bending radius R of the connection portion between the extension member portion 31b and the connection portion 31c and the bending radius R of the connection portion between the extension member portion 31d and the connection portion 31c need to be relatively small so as not to interfere with other coil pieces.

[0034] When the inner coil pieces 21 are incorporated as shown in FIG. 3B, the four connection portions 21c are arranged such that they overlap in the axial direction of the rotation axis. Similarly, four types of outer coil pieces 31 with different sizes are prepared, and when they are incorporated as shown in FIG. 3B, the four connection portions 31c are arranged such that they overlap in the axial direction of the rotation axis.

[0035] As shown in FIG. 3B, four types of connection portions 11c of the central four coil pieces 11 with different sizes are prepared, and are arranged side by side in the radial direction from the inner side to the outer side at the same position in the axial direction of the rotation axis from the inner side to the outer side. The shape of the connection portion 11c is not linear, but is formed in an arc shape along the circumferential direction of the stator core 3 in the circumferential direction. The height of the coil piece 11a (the height from the stator core end) is h 4 is. Also, four types of inner four coil pieces 21 with different sizes are prepared, and their connection portions 21c are arranged side by side at the same position in the radial direction so as to be laminated in the axial direction. The shape of the connection portion 21c is not linear, but is formed in an arc shape along the circumferential direction of the stator core 3. The maximum height of the laminated coil pieces 21a (the maximum height from the stator core end) is h 5 is. Further, four types of outer coil pieces 31 with different sizes are prepared, and their connection portions 31c are arranged side by side at the same position in the radial direction so as to be laminated in the axial direction. The shape of the connection portion 31c is not linear, but is formed in an arc shape along the circumferential direction of the stator core 3. The maximum height of the laminated coil pieces 21a (the maximum height from the stator core end) is h 6 is. Here, the height h 4 > h 5 , and, h 4 > h 6 is preferably in the relationship of. h5 and h 6 The magnitude relationship between them is arbitrary.

[0036] As described above, the inner coil piece 21 is shaped such that the flat angle lines rising from the straight portions 21a and 21e are bent radially inward without interfering with the connection portion 11c of the four central coil pieces 11 and do not protrude inward beyond the innermost diameter portion of the stator core 3. As shown in Fig. 3B, the coil piece 21 rising from the radially inner side of the slot 3c is configured to have the lowest coil height. In the coil piece 21 at the next position in the radial direction, the coil height is increased so that the connection portion 21c is arranged above the innermost coil 21 with a thickness of the wire and a slight gap secured. The position of the connection portion 21c of the coil 21 rising from the next position in the radial direction (the third insertion hole from the inside) is further raised, and the position of the connection portion 21c of the coil 21 rising from the further next position in the radial direction (the fourth insertion hole from the inside) is further raised. Similar to the central coil piece 11, the inner coil piece 21 also has recesses 21f and 21g formed at the coil end portions (the end portions of the straight portions 21a and 21e opposite to the coil ends), and the cut surface is tin-plated.

[0037] In Fig. 3B, only the slot 3c portion into which the coil piece 21 is inserted is shown without the illustration of the bobbin 65 so that the shape and arrangement location of the end portions (21f, 21g) of the coil piece 21 can be understood. The concave-side coil piece 21 is set to be shorter than the axial length of the counter-opening side 2b of the stator core 3 in the rotational axis direction so as not to protrude from the end portion of the stator core 3. The recesses 21f and 21g and the fitting portions with the protrusions 20f and 20g to be described later in Fig. 4 are arranged at portions located inward from the end portion at a predetermined interval. Also in the other coil pieces, that is, the central coil piece 11 and the outer coil piece 31, the axial positions of the recesses 11f, 11g, 31f, and 31g formed at the end portions are the same.

[0038] The outer coil piece 31 is formed into a shape that bends the flat angle lines rising from the straight portions 31a and 31e radially outward so as not to interfere with the central coil piece 11. Since there is often a margin in the core back portion for the outer coil piece 11, it can be configured by bending it largely outward. Also in this embodiment, the bending angle θ 6 is set to about 45 degrees, which is a relatively large angle. At this time, as shown in FIG. 3B, the coil piece 11 rising from the innermost side of the slot insertion hole is configured such that the coil height of the connection portion 11c is the highest, and in the coil piece 11 of the second insertion hole, the coil height is arranged lower so that it is disposed below the coil piece 11 rising from the first insertion hole with a line thickness and a slight gap ensured. Similarly, the connection portion 11c of the coil piece 11 rising from the third insertion hole from the inside is further downward, and the connection portion 11c of the coil piece 11 rising from the fourth insertion hole is below that, and the shapes of the respective coil pieces 11 are designed in this manner. At the ends of these outer coil pieces 11c, recesses 31f and 31g are formed and tin plating is applied in the same manner as for the inner coil piece 31.

[0039] FIGS. 4A to 4D are partial configuration diagrams for explaining the configuration in the axial direction (lead-out wire side) of the stator core 3 for forming the stator 2 shown in FIG. 1A, and perspective views for explaining each coil shape. FIG. 4A shows a part of the axial projection view of the lead-out side 2a of the stator core 3, and FIG. 4B is a perspective view thereof. Since there are lead-out wires 41 to 46 on the lead-out side 2a of this stator core 3, the way of spanning between the slots 3c is different from that in FIGS. 3A and 3B.

[0040] FIG. 4C is a perspective view of the central coil piece 10. The coil piece 10 is formed in a hairpin shape, in other words, a substantially U shape, and is formed by straight portions 10a and 10e formed linearly, extending portions 10b and 10d extending outside the slot 3c, and a connection portion 10c connecting between the axially separated ends of the extending portions 11b and 11d. Among these, the extending portions 10b and 10d and the connection portion 10c form the coil end portions. The extending portions 10b and 10d of the coil piece 10 are at an angle θ with respect to the straight portions 10a and 10e 1It is configured to be bent only radially outward. Also, due to the relationship of the overall arrangement space of the stator coil 9, in order to secure an installation area for the outer peripheral side portion rather than the connection portion 10c of the coil piece 10, and also, the bending radius R of the connection portion between the extension member portion 10b and the connection portion 10c and the bending radius R of the connection portion between the extension member portion 10d and the connection portion 10c are made relatively small so as not to interfere with other coil pieces. The ends of the coil piece 10 are formed (cut) as convex portions 10f and 10g. This dimensional relationship is made into a shape suitable for fitting with the concave portions 11f and 11g of the coil piece 11 (see FIG. 2C) with connection symmetry by press-fitting. Also, on the cut surfaces of the convex portions 11f and 11g, tin plating is formed in the same manner as the concave portions 10f and 10g.

[0041] The lead-out lines 41 to 43 are accommodated in the innermost peripheral insertion hole 66a among the plurality of insertion holes 66a to 66d formed in the bobbin 65. The inner coil piece 20 is such that the insertion holes 66b to 66d where the lead-out line 41 is located form a concentric coil through the outer coil piece 31 (see FIG. 3B) on the anti-lead-out side 2b, and are connected to the insertion holes 66a to 66c of the slot 3c on the side that spans 5 slots (37.5 degrees) in the circumferential direction, so that the lead-out lines 41 and 44 are connected. The portion of the central coil piece 10 is such that the innermost peripheral insertion hole 66a where the lead-out line 42 is located forms a concentric coil through the central coil piece 11 (see FIG. 3B) on the anti-lead-out side 2b, and is connected to the lead-out line 45 of the outermost insertion hole 66d of the slot 3c that spans 5 slots in the circumferential direction. Incidentally, the central coil piece 10 is composed of three types: a piece that connects the starting slot insertion hole 66b and the slot insertion hole 66a on the side that spans 5 slots in the circumferential direction, a piece that connects the starting slot insertion hole 66c and the slot insertion hole 66b on the side that spans 5 slots in the circumferential direction, and a piece that connects the slot insertion hole 66d and the slot insertion hole 66c on the side that spans 5 slots in the circumferential direction. The portion of the outer coil piece 45 is such that the innermost peripheral insertion hole 66a where the lead-out line 43 is located forms a concentric coil through the inner coil piece 21 (see FIG. 3B) on the anti-lead-out side 2b, and is connected to the lead-out line 46 of the outermost insertion hole 66d of the slot 3c that spans 5 slots in the circumferential direction.

[0042] In FIG. 4F, the shape of the outlet coil piece 41 is shown. The shapes of the outlet coil pieces 41 to 46 are exactly the same, and common parts can be used. The outlet coil piece 41 is formed by bending a nichrome wire with a rectangular cross-sectional shape into a crank shape. With the straight portion 41a, the bent portion 41b, and the extension portion 41c, the nichrome wire has a stepped structure near the center in the longitudinal direction. As shown in FIG. 4B, the coil pieces 41 to 46 have dimensional relationships such that they do not interfere with the respective coil pieces 10, 20, and 30 during installation.

[0043] Prepare three types of coil pieces 10, 20, and 30 shown in FIGS. 4C, 4D, and 4E with slightly different sizes, and prepare the outlet coil pieces 41 to 46 with the same dimensions. Then, on the outlet side 2a of the stator 2, a stator coil 9 for one phase as shown in FIG. 4A is formed. The outlet wire 40 on the radially inner side of the stator coil 9 protrudes inward beyond the innermost position of the stator core 3. In this embodiment, this is because there is no margin on the inner side. However, if a design with a margin on the inner side is adopted, the outlet coil pieces 41 to 43 can also be configured to fit outside the inner diameter of the stator 2. Also, the lengths of the straight portions (10a, 10e, 20a, 20e, 30a, 30e, 41a, etc.) of each coil piece are formed to be longer than the length of the outlet side 2a of the stator core 3, and the ends where the convex portions (10f, 10g, 20f, 20g, 30f, 30g, 41f, etc.) of each coil piece are formed project into the stator core 3 on the opposite outlet side 2b with such dimensional relationships.

[0044] FIG. 5C is a perspective view of the stator 2 of the radial-gap type rotating electrical machine 1 according to an embodiment of the present invention, showing a state in which all coils are mounted circumferentially by concentric winding of rectangular conductors. FIG. 5A is a perspective view of the lead-out side 2a portion of the stator 2 (before joining with the anti-lead-out side 2b portion), and FIG. 2B is a perspective view of the anti-lead-out side 2b portion of the stator 2 (before joining with the lead-out side 2a portion), which is a perspective view seen from the opposite side in the direction of the rotation axis (from the direction of arrow 70 in FIG. 1). The stator on the lead-out side 2a and the stator 2b on the anti-lead-out side are combined in the direction of the rotation axis, and at the inside of the resin bobbin 65 and on the stator 2b side, concave portions (10f, 10g, 20f, 20g, 30f, 30g, 41f, etc.) and convex portions (11f, 11g, 21f, 21g, 31f, 31g) are engaged with each other to form coils. At this time, as shown in FIG. 1, in order to balance the resistance values of the coils, the inner coil piece 20 on the lead-out side 2a side and the outer coil piece 31 on the stator 2b side are axially combined and concentrically wound, and the outer coil piece 30 on the lead-out side 2a side and the inner coil piece 21 on the stator 2b side are axially combined and concentrically wound. Near the center in the radial direction, the central coil piece 10 on the lead-out 2a side and the central coil piece 11 on the anti-lead-out side 2b side are combined to form a concentric winding. In addition, when the lengths in the direction of the rotation axis Ax of the stator cores 3 on the lead-out side 2a and the anti-lead-out side, which have a split structure, are equal, the lengths of the straight portions 10a, 10e, 20a, 20e, 30a, 30e of the coil pieces 10, 20, 30 on the lead-out side 2a are formed longer than the lengths of the straight portions 11a, 11e, 21a, 21e, 31a, 31e of the coil pieces 11, 21, 31 on the anti-lead-out side 2b.

[0045] Next, the winding structure of the stator coil 9 of the present embodiment will be described. Before describing the structure of the present embodiment, the winding structure of a conventional coil will be described with reference to FIGS. 6 and 7. FIG. 6A is a perspective view showing a configuration of one phase of a wave-wound structure stator using a rectangular wire as a conventional example, FIG. 6B is a circuit diagram of a two-parallel delta connection, and FIG. 6C is a connection diagram thereof. FIG. 6A shows the upper half of FIG. 6C.

[0046] The small numbers enclosed in circles, namely, circle 1 and circle 8, are the outgoing lines. The coil that enters from the inner outgoing line circle 1 is connected to the second insertion hole of slot 43, which is 6 slots ahead in the circumferential direction, via the lower coil end, and is connected to slot 37, which is 6 slots ahead in the circumferential direction, via the upper coil end. Then, it is connected to slot 8, which extends for 5 slots in the circumferential direction by the short-pitch coil 17 via slot 31, slot 25, slot 19, and slot 13. After that, it is connected by a coil that extends for 6 slots and makes one round through slots 2, 44, 38, 26, 20, and 14. Then, it is connected by the long-pitch coil 16 and moves to the third insertion hole, and rotates two rounds from slot 1 in the same manner as described above, and the outgoing line comes out from the fourth insertion hole of slot 8. This becomes the U-phase of system 1 with circle 1 and circle 8 as the terminals. It is connected as the U-phase coil 18 of system 1 in FIG. 6B. Similarly, the U-phase coil that enters from circle 14 and is connected to circle 7 is configured as system 2. This is connected as the U-phase coil 19 of system 2 in FIG. 6B. As can be seen from this, in the wave winding, since the divided coil pieces are connected in the circumferential direction to form the winding, the number of coils cannot be made more than the number of slots per pole per phase. In an 8-pole 48-slot case, the number of coils per phase becomes 2.

[0047] FIG. 7 is a perspective view showing the configuration of one phase of a spiral structure stator using a flat angle wire as another conventional example, FIG. 7B is a circuit diagram of a two-series delta connection, and FIG. 7C shows its connection diagram. In the winding shown in FIG. 6, since the number of coils is 2, in addition to the two-delta connection shown in FIG. 6, a one-delta connection in which two coils of the same phase are connected in series can be configured. That is, as shown in FIG. 7B, two coils, namely, the round 1-round 8 coils and the round 14-round 7 coils that make up the U phase, are connected in series, and the other phases are similarly delta-connected with two coils of the same phase connected in series, thus enabling this configuration. By being able to configure this, rotating electrical machines with multiple voltage specifications, for example, 200V specification and 400V specification, can be realized with the same winding configuration by simply changing the connection of the wiring. Also, although not shown, as another configuration, it is possible to make a Y connection, and it is also possible to configure a two-series one-Y connection and a two-Y parallel connection. However, since the number of turns cannot be changed, the voltage change is a 1.73-fold change.

[0048] Next, the winding structure of the stator coil 9 of this embodiment will be described. FIG. 8A is a perspective view showing the configuration of one phase of a concentric winding structure stator using the flat angle wire of the present invention, FIG. 8B is a circuit diagram of a two-parallel delta connection, and FIG. 8C shows its connection diagram. Only the U-phase coil is shown in FIGS. 8A to 8C. Comparing FIG. 8C with FIG. 6C, it can be seen that the U-phase coil is placed in the same slot. In this embodiment, since it is configured by concentric winding, it is composed of 8 partial coils in 5 slots (skipping 37.5 degrees) (the coils in slot numbers 2 and 7, 8 and 13, 14 and 19, 20 and 25, 26 and 31, 32 and 37, 38 and 43, 44 and 1). In FIG. 8C, the partial coils of the concentric winding are connected in series so that 4 partial coils are in series, and a partial coil group 28 of system 1 and a partial coil group 29 of system 2 are formed. By connecting this partial coil group 28 of system 1 to the U-phase coil part in FIG. 8B to form a stator coil 50a, and connecting the partial coil group 29 of system 2 to the U-layer part of another delta connection to form a stator coil 50b, the coil in the circuit diagram of FIG. 8B is obtained.

[0049] FIG. 9A is a perspective view showing the configuration of another one-phase of the stator 2 with a concentric winding structure using the flat angle wire of the present invention, FIG. 9B is a circuit diagram of a two-series delta connection, and FIG. 9C shows its connection diagram. Similar to the conventional example of FIG. 7, in the concentric winding structure, since the configurations of the two coil groups 28 and 29 are possible, these two can be connected in series to correspond to one delta connection as shown in FIG. 9B. As a result, a motor configuration corresponding to two specifications of 200V and 400V becomes possible.

[0050] FIG. 10A is a circuit diagram of an 8-parallel delta connection showing another configuration of one-phase of the concentric winding stator 2 using the flat angle wire of the present invention, and FIG. 10B shows its connection diagram. As shown in FIG. 10B, in the concentric winding, in the case of this embodiment, it is composed of eight coils 32 to 39. Therefore, a connection configuration up to 8-parallel is possible. FIGS. 10A and 10B show the configuration of an 8-parallel delta connection in which all coils are in parallel, but as shown in FIG. 10B, by using coils 32 to 39 for each concentric winding, 8-parallelization can be achieved. Naturally, 2-series 4-parallelization is also possible. As a result, it becomes possible to correspond to four voltage specifications.

[0051] FIG. 11 is a circuit configuration diagram of a control system of a rotating electrical machine when the concentric winding stator 2 is driven by two inverters. In a large-capacity rotating electrical machine 1A, when driving, rather than increasing the capacity of the driving circuit (inverter) for driving and driving one rotating electrical machine with one driving circuit, in some cases, it is possible to reduce the cost of the driving circuit by dividing the driving circuit into two and driving, and there are cases where a plurality of control circuits are used for driving for reasons such as being able to disperse the heat generated in the power device part of the driving circuit. At this time, a method is adopted in which the winding is divided into two and shared by each driving circuit.

[0052] FIG. 11 shows the connection configuration, in which the control circuit 52a of system 1 is connected to the winding 50a of system 1, and the control circuit 52b of system 2 is connected to the stator winding 50b of system 2 for driving. The power supplies of the control circuits 52a and 52b are respectively connected to the systems separately, and different direct currents are generated by different rectifier circuits 51a and 51b to perform PWM (Pulse Width Modulation) switching to drive the rotating electrical machine. Although not shown in FIG. 11, a driving device having a microcomputer is provided to control the on / off of the gate signals of the control circuits 52a and 52b. When taking these configurations, it can be seen that the windings of the rotating electrical machine 1 must have two or more sets like 50a and 50b. In the example of the wave winding shown in FIGS. 6A and 7A, since only two in-phase windings can be made, the switching between the 200V and 400V specifications is possible, but the driving method using two control circuits cannot be adopted when the 400V specification (2 series 1 delta connection) is used. That is, it can be seen that in order to realize the switching of the voltage specification and the driving of two control circuits with a rotating electrical machine 1 of one winding specification, four or more coils per phase are required. In the concentric winding structure of the present invention, since it can be divided into up to eight coils, this becomes possible.

[0053] FIG. 12 shows the coil slot arrangement model of the stator 202 with a wave winding structure using flat lines, and FIGS. 13A and 13B show the calculation results of the linked magnetic flux by magnetic field analysis using the model. When driving two coil groups as shown in FIG. 11 using two control circuits, magnetic interference between the coils may be a problem. When the coupling coefficient between two coils is high, when the operation of one control circuit does not match that of the other control circuit, an induced voltage is generated between the coils, and due to the influence, a phenomenon occurs in which the currents are distorted from each other. FIG. 13A is the result of confirming this phenomenon by magnetic field analysis. FIG. 13A shows the slot arrangement in the case of a wave winding. As shown by the slot 204, the coils U1 and U2 of system 1 are alternately mixed in one slot 204. The same is true for other phases. In one slot, V1 and V2 of system 1 are alternately mixed, and W1 and W2 of system 1 are alternately mixed.

[0054] Figure 13A shows the result of the generation of the linked magnetic flux in the other coil (system 2) when a sine wave is applied to one side (system 1) of this coil. The horizontal axis in Figure 13A is time (unit: second), and the vertical axis is the linked magnetic flux (Wb). Although the analysis is performed with three-phase alternating current, only the U phase is shown here. The magnetic flux of u1 on the side where the current is applied is shown by a solid line, and the magnetic flux of u2 where the linked magnetic flux is detected is shown by a dotted line. However, since both coincide exactly, the graph is shown only by the solid line. Figure 13B shows the linked magnetic flux and the coupling coefficient for three phases. It can be confirmed that the coupling coefficient is 1 for all three phases, indicating a high degree of magnetic influence. This means that it is not suitable for driving with two control circuits for the coils with a wave winding structure.

[0055] Figure 14 shows the coil slot arrangement model of the stator 2 with a concentric winding structure using a flat wire according to this embodiment. In the calculation model for the case of concentric winding, only coils of the same system can be placed in the same slot. For example, only the coil of phase V1 is arranged in slot 301. This circuit is the case of the two-parallel delta connection shown in Figure 8. The chain line indicated by reference numeral 71 shows the boundary between the U1 coil and the U2 coil. Figure 15B shows the calculation result regarding the magnetic interference of the coils. In the case of concentric winding, since it is composed of four coils in the circumferential direction, it is considered that the influence is small for the coils other than near the boundary. Comparing u1 and u2, unlike the result where the two in Figure 13A coincide, as shown in Figure 15A, the linked magnetic flux of coil u2 with respect to coil u1 is small. Figure 15B shows the calculation result of the linked magnetic flux by magnetic field analysis using the model. Here, the coupling coefficient is about 0.1, indicating that the magnetic interference is small.

[0056] Next, the assembly order of the concentric winding stator 2 according to this embodiment will be described with reference to Figures 16A to 16H. Figures 16A to 16D are projection views of the insertion and assembly side (the outlet side) of the stator 2, and Figures 16E to 16H are perspective views (for one phase) of the stator 2 in Figures 16A to 16D, and the upper and lower figures correspond to each other.

[0057] Figure 16A shows the stator core 3 in the assembled state. From this state, coil pieces will be inserted into the insertion holes 66a to 66d of the bobbin 35 in the slot 3c while considering the assembly order. In Figure 16B, the lead-out lines 41 to 43 are inserted into the inner peripheral insertion hole 66a, and the lead-out lines 44 to 46 are inserted into the slot hole 66d on the outer peripheral side. The lead-out lines 41 to 43 are repeatedly inserted into the slots that are one slot apart from the slot at the starting point 60, so that the lead-out lines 41 to 43 for one round in the circumferential direction are inserted. The outer lead-out lines 44 to 46 are inserted from a position five slots away from the starting point 60 for one round in the circumferential direction. Note that the insertion order of the lead-out lines 41 to 46 is arbitrary. In short, the lead-out lines (41 to 43) are inserted into the inner peripheral insertion hole 66a every other slot in the circumferential direction, and the lead-out lines (44 to 46) are inserted into the outer peripheral insertion hole 66d every other slot in the circumferential direction, either in order or in any order. Looking at the projection view in Figure 16B, it can be seen that after the insertion of the lead-out lines 40 and 41, the holes of the insertion holes other than the ones where the lead-out lines 40 and 41 are inserted are visible on the projection plane. Similarly, for the inner peripheral insertion holes 66a that form other phases, the lead-out lines 41 to 46 are inserted every other one in the circumferential direction. For the outer peripheral insertion holes 66d, the lead-out lines 44 to 46 are inserted in the same way every other one in the circumferential direction.

[0058] In Figure 16C, three inner coil pieces 20 and three outer coil pieces 30 are inserted. The inner coil pieces 20 are inserted into the second insertion hole 66b from the inside of the starting point 60 and the insertion hole 66b that is five slots away from the starting point 60 in the circumferential direction. The coil piece 20 is similarly inserted into the outer insertion hole 66c, and further into the outer insertion hole 66d. In this way, the inner coil pieces 20 are inserted in order from the second inner insertion hole 66b to the fourth insertion hole 66d. As a result, the connection part 20c of the coil piece 20 inserted into the insertion hole 66d is located at the top, and the connection part 20c of the coil piece 20 inserted into the insertion hole 66b is located at the bottom and stacked. The operation of inserting three coil pieces 20 as described above, starting from a position ten slots away from the starting point 60 in the circumferential direction and inserting three coil pieces 20, is repeated six times (for six layers) for the entire circumferential direction.

[0059] The outer coil piece 30 is first inserted into the third insertion hole 66c from the inside of the slot that is four slots away in the circumferential direction from the starting point 60 and the insertion hole 66c of the slot that is nine slots away in the circumferential direction from the starting point 60. For the outer coil piece 30, it is necessary to insert it in order from the third outer insertion hole toward the inside. First, the lead wires 44 and 46 are inserted into the fourth outer insertion hole, then the coil piece 30 is inserted into the third insertion hole, then the coil piece 30 is inserted into the second insertion hole, and finally the coil piece 30 is inserted into the first insertion hole. At this time, the bent portion 46b of the lead wires 44 and 46 is in a position close to the stator core 3, the connecting portion 30c of the coil piece 30 inserted into the third insertion hole is adjacent in the axial direction of the rotation axis to the connecting portion 30c of the coil piece 30 inserted into the second insertion hole and further adjacent to it, and the connecting portion 30c of the coil piece 30 inserted into the first insertion hole is in a position farthest from the stator core 3. By laminating in this way so that the coil ends are inserted in order from the one with the lowest height, as shown in the projection view of FIG. 16C and the perspective view of FIG. 16G, it can be confirmed that the insertion holes 66a to 66d indicated by the arrows 72a and 72b for inserting the central coil piece are visible when viewed from the axial direction of the rotation axis even after the insertion of the coil pieces 20 and 30.

[0060] Next, as shown in FIGS. 16D and 16H, three central coil pieces 30 are inserted into the positions indicated by the arrows 72a and 72b. The central coil piece 30 is first inserted into the outermost insertion hole 66d of the second slot in the circumferential direction from the starting point 60 and the third insertion hole 66c from the inside of the seventh slot in the circumferential direction from the starting point 60. After that, it is inserted into the third insertion hole 66c from the inside of the second slot in the circumferential direction from the starting point 60 and the second insertion hole 66b from the inside of the seventh slot in the circumferential direction from the starting point 60, and finally, it is inserted into the second insertion hole 66b from the inside of the slot that is two slots away in the circumferential direction from the starting point 60 and the innermost insertion hole 66a of the slot that is seven slots away in the circumferential direction from the starting point 60. In this embodiment, since the coil end portion of the coil piece 10 is tilted outward by about 5 degrees as shown by the angle θ in FIG. 4C, it is preferable to insert the coil piece 10 in order from the fourth outer insertion hole. Also, the connecting portions 10c of the three types of inserted coil pieces 10 have the same height H with respect to the axial direction. 1 as shown, it is preferable to insert the coil piece 10 in order from the fourth outer insertion hole. Also, the connecting portions 10c of the three types of inserted coil pieces 10 have the same height H with respect to the axial direction. 1Align them radially.

[0061] Insert the three central coil pieces 20 as described above. Starting from the starting point 60, repeat the operation of inserting the three coil pieces 20 with a position 10 slots away in the circumferential direction as the new starting point, six times (for six layers) for the entire circumferential direction. In this way, the assembly of the stator coil 9 on the lead-out side is completed, and the completed state is the state shown in Fig. 5A.

[0062] In the order of assembling the coil pieces 11, 21, and 31 on the non-lead-out side of the stator core 3, basically, it is the same as the assembly method shown in Figs. 16C and 16D. On the non-lead-out side 2b, since the lead wires corresponding to symbols 41 to 46 are not used, four coil pieces 11, 21, and 31 are inserted each time. First, insert the inner peripheral coil piece 21 into the slots 3c in order from insertion hole No. 1 to No. 4, and repeat this operation for eight phases in the circumferential direction. Next, insert the outer peripheral coil piece 31 into the slots 3c in order from insertion hole No. 4 to No. 1, and repeat this operation for eight phases in the circumferential direction. Next, insert the central coil piece 11 into the slots from No. 4 to No. 1 in order, and repeat this for eight phases in the circumferential direction to complete the assembly of the coil pieces on the non-lead-out side 2b. This completed state is the state shown in Fig. 5B. Note that the insertion order of these coil pieces does not necessarily have to be as described above. For example, the assembly order of the inner coil piece 20 and the outer coil piece 30 can be reversed, and it is also possible to first incorporate the outer coil piece 30 and then the inner coil piece 20.

[0063] While temporarily fixing the stator cores 3 on the lead-out side 2a and the non-lead-out side 2b assembled as shown in Figs. 5A and 5B so that the coil end portions of each coil piece 3 do not move in the axial direction of the rotation axis, join the stator core parts on the lead-out side 2a and the non-lead-out side 2b, so that the convex portions of the coil pieces 10, 20, 30, 40, 41 to 46 and the concave portions of 11, 21, and 31 are also fitted. Through such a procedure, the mechanical assembly of the stator 2 is completed.

[0064] As can be seen from FIG. 6A, in the case of the coiled coil pieces according to the conventional example, since adjacent coil pieces cross and are intertwined, it is impossible to assemble them one by one in order. Before inserting them into the bobbin of the stator core, it is necessary to attach them collectively in a state where the coil pieces are fixed together into the slots 3c all at once. Also, it is difficult to remove the coil pieces one by one after assembly. In the case of the coil pieces 10, 11, 20, 21, 30, 31 with the concave-convex fitting of the concentric winding configuration according to the present embodiment, it can be said that there are advantages in coil assembly compared to the wave winding.

[0065] As described above, according to the present invention, by combining the outer coil pieces 30, 31, whose coil end portions are longer, with the inner coil pieces 20, 21, respectively, the central coil that connects in the circumferential direction at the same diameter as the radial position of the slot is designed such that its circumference, that is, its resistance value, is the same as the circumference of the coil created by connecting the inner coil piece and the outer coil piece. As a result, while using a rectangular conductor to form a concentric winding, it is possible to homogenize the resistance value and inductance of the coil.

[0066] By adopting the coil configuration as in the present invention, a concentric-wound stator coil 9 with a high conductor occupancy rate and little variation in coil resistance between phases can be formed. As a result, motor design and system design that take advantage of the characteristics of the concentric-wound coil configuration become possible. In addition, since the number of coils can be set regardless of the number of slots per pole per phase, the degree of freedom in design for whether to form a series circuit or a parallel circuit during connection increases, and design changes in response to different voltage specifications and frequencies (rotational speed, torque) can be easily made. In the case of concentric winding, since the number of turns per slot, which cannot be configured in wave winding, can be designed to be an odd number, the degree of freedom in design for coping with the above-mentioned specification changes can be increased. Furthermore, since the coils have an independent structure between systems, magnetic interference can be reduced, and there are fewer restrictions on the number of drive circuits to be used. Additionally, when assembling the concave-convex fitting of the stator coil, by setting the insertion order of the coils to be appropriate, there is an advantage that the assembly can be performed while performing the concave-convex fitting process simultaneously with the insertion. Note that the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope not departing from the gist thereof.

Explanation of Signs

[0067] 1, 1A Rotating electrical machine 2 Stator 2a Outlet side 2b Opposite outlet side 3 Stator core 3a Core back core 3b Tooth core 3c Slot 3d Recess 4 Housing 4a Body part 4b, 4c End bracket 5 Rotating shaft 6 Rotor 7 Rotor core 8 Permanent magnet 9 Stator coil 10, 11 Central coil piece 11a, 11e Straight part 11b, 11d Extension part 11c Connection part 15 Standard pitch coil 16 Long pitch coil 17 Short pitch coil 18 Wave-wound coil group 1 19 Wave-wound coil group 2 20, 21 Inner coil pieces 30, 31 Outer coil pieces 28 (First) partial coil group 29 (Second) partial coil group 32 - 39 (1 - 8) Concentric winding coil groups 41 - 46 Tap coil pieces 50a (Winding of system 1) 50b (Winding of system 2) 51 Rectifier (converter) 52a, 52b Control circuit (inverter) 53a, 53b System power supply (three-phase) 65 Resin bobbin 66a - 66d Insertion holes 67, 68 Jaw parts 67a, 68a Claw parts 100 Air compressor 101 Air end 102 Casing 105 First shaft 110 First bevel gear 120 M rotor 130 Second bevel gear 135 Second shaft 140 F rotor 145 Tooth space 202 Stator Ax Axis of rotation

Claims

1. A rotor fixed to a rotating shaft, and a stator including a stator core in which a plurality of slots for accommodating a plurality of straight angle lines in the circumferential direction are formed on one side or the other side in the axial direction of the rotating shaft, and a plurality of U-shaped coil pieces formed by the straight angle lines are inserted into and connected in the slots to form a coil, wherein the coil piece is formed by a straight angle line, has two straight portions that become portions accommodated in the slots separated in the circumferential direction, and a coil end portion formed to extend outward in the direction of the rotation axis from the straight portions to connect the two straight portions, as the coil piece, a central coil piece in which the straight portion and the coil end portion are arranged on a circumference in a plan view from the axial direction of the rotation axis, an inner coil piece in which the coil end portion bends radially inward with respect to the portion accommodated in the slot, an outer coil piece in which the coil end portion bends radially outward with respect to the portion accommodated in the slot is provided, the circumferential length of the coil end portion of the inner coil piece is made shorter than the circumferential length of the coil end portion of the central coil piece, and the circumferential length of the coil end portion of the outer coil piece is made longer, a pair of the central coil pieces are inserted and electrically connected from one side or the other side in the axial direction of the rotation axis with respect to the first slot set, the inner coil piece and the outer coil piece line are inserted and electrically connected from one side or the other side in the axial direction of the rotation axis with respect to the second or third slot set to form a concentric-wound stator coil. The rotating electrical machine is characterized by this.

2. In the rotating electrical machine according to Claim 1, the coil end portion is formed by two extending portions extending outward in the direction of the rotation axis from the straight portion of the coil piece and a connecting portion connecting the ends of the extending portions in the circumferential direction, after the stator coil is connected, the connecting portions of the central coil pieces are arranged to be aligned in the radial direction, by providing an angle such that the extending portion of the inner coil piece bends radially inward, the connecting portion of the inner coil piece is arranged to be laminated in the axial direction at a portion radially inner than the laminated portion of the central coil piece, by providing an angle such that the extending portion of the outer coil piece bends radially outward, the connecting portion of the outer coil piece is arranged to be laminated in the axial direction at a portion radially outer than the laminated portion of the connecting portion of the central coil piece. The rotating electrical machine is characterized by this.

3. In the rotating electrical machine according to claim 2, the bending angle of the extension part inward with respect to the straight part of the inner coil piece is an angle greater than 0 degrees and equal to or less than 45 degrees, the bending angle of the extension part outward with respect to the straight part of the outer coil piece is an angle greater than 0 degrees and equal to or less than 45 degrees, a rotating electrical machine, characterized in that the coil length of one turn is made equal to the coil length of one turn by the two central coil pieces by alternately connecting the inner coil pieces and the outer coil pieces.

4. In the rotating electrical machine according to claim 3, when inserting the coil pieces into the slots of the stator core from both sides in the rotating shaft direction, the central coil piece, the inner coil piece, and the outer coil piece can be inserted and assembled one by one in parallel in the rotating shaft direction. A rotating electrical machine characterized by this.

5. In the rotating electrical machine according to claim 1, a rotating electrical machine characterized in that by forming the stator coil in concentric windings, a number of parallel connections greater than the number of slots per pole per phase can be configured.

6. In the rotating electrical machine according to claim 3 the stator core is composed of a core back core and a plurality of tooth cores combined with the core back core, a rotating electrical machine characterized in that a low-loss soft magnetic material is used as the tooth core, and resin bobbins for accommodating a plurality of flat wires in the radial direction are respectively arranged in the slots between the adjacent tooth cores.

7. In the rotating electrical machine according to claim 3, a rotating electrical machine characterized in that it is configured to be able to simultaneously support a plurality of voltage specifications and a plurality of control devices with one winding specification.

8. In the rotating electrical machine according to claim 3, a rotating electrical machine characterized in that an odd number of turns are formed in one of the slots.

9. In the rotating electrical machine according to any one of claims 1 to 8, the stator coil has a parallel delta winding configuration, a plurality of inverter devices are respectively provided in each delta winding part, a control system for a rotating electrical machine, characterized in that an exciting voltage is independently supplied to the delta winding part by the inverter device.

10. A control system for a rotating electrical machine according to claim 9, a control system for a rotating electrical machine, characterized in that converter circuits corresponding to the inverter circuits are respectively provided, and power is supplied to the converter circuits from independent system power supplies.

11. A rotor fixed to a rotating shaft, A stator including a stator core disposed on the outer peripheral side of the rotor and having a plurality of slots formed in the circumferential direction, and a stator coil formed by a plurality of U-shaped coil pieces made of flat wires inserted into the slots from the lead-out side or the anti-lead-out side in the rotational axis direction. In a rotating electrical machine comprising: A bobbin having a slot hole for accommodating m flat wires in the radial direction is disposed in each of the slots. As the coil piece inserted from the lead-out side in the rotational axis direction, a) m-1 types of central coil pieces, m-1 types of outer coil pieces with the coil end portion bent so that the coil end portion bends outward in the radial direction, and m-1 types of inner coil pieces with the coil end portion bent so that the coil end portion bends inward in the radial direction, as a group of the coil pieces formed by two straight portions accommodated in the slot holes separated by 5 slots in the circumferential direction and a coil end portion formed so as to extend outward from the straight portions in the rotational axis direction and extending in the rotational axis direction and the circumferential direction to connect the two straight portions. b) Starting from the slot hole where the inner coil piece is located, the m-1 types of inner coil pieces are arranged over the entire circumference in the circumferential direction such that the connecting portions extending in the circumferential direction of the coil end portions are laminated in the radial direction. c) Starting from the slot hole at a position separated by 4 slots in the circumferential direction from the starting point of the inner coil piece, the m-1 types of outer coil pieces are arranged over the entire circumference in the circumferential direction such that the connecting portions extending in the circumferential direction of the coil end portions are laminated in the rotational axis direction. d) Starting from a position separated by 2 slots in the circumferential direction from the starting point, the m-1 types of central coil pieces are arranged over the entire circumference in the circumferential direction such that the connecting portions extending in the circumferential direction of the coil end portions are aligned in the radial direction. As the coil piece inserted from the anti-lead-out side in the rotational axis direction, e) m types of central coil pieces, m types of outer coil pieces with the coil end portion bent so that the coil end portion bends outward in the radial direction, and m types of inner coil pieces with the coil end portion bent so that the coil end portion bends inward in the radial direction, as a group of the coil pieces formed by two straight portions accommodated in the slot holes separated by 5 slots in the circumferential direction and a coil end portion formed so as to extend outward from the straight portions in the rotational axis direction and extending in the rotational axis direction and the circumferential direction to connect the two straight portions. f) From the slot holes starting from the inner coil pieces, perform for the entire circumference over the circumferential direction such that m - 1 kinds of the inner coil pieces are radially laminated with connection portions extending in the circumferential direction of their coil end portions. g) From the slot holes at a position 4 slots circumferentially away from the starting point of the inner coil pieces, perform for the entire circumference over the circumferential direction such that m - 1 kinds of the outer coil pieces are axially laminated with connection portions extending in the circumferential direction of their coil end portions. h) Starting from a position 2 slots circumferentially away from the starting point, for m - 1 kinds of the central coil pieces perform for the entire circumference over the circumferential direction such that connection portions extending in the circumferential direction of their coil end portions are radially aligned. A method for manufacturing a stator in a rotating electrical machine, characterized in that a coil formed as a concentric winding is formed by connecting a set of coil pieces inserted into the slots of the stator core from the lead-out side and a set of coil pieces inserted from the opposite lead-out side within the slot holes.

12. In the manufacturing method according to Claim 11, prepare a plurality of lead-out wires having a shape in which a straight flat wire is bent into a crank shape, at the lead-out side in the axial direction of the rotating shaft, before executing the procedure of b), arrange one lead-out piece in the innermost circumferential slot hole on the starting side for accommodating the inner coil pieces and arrange one lead-out piece in the outermost circumferential slot on the other side. before executing the procedure of c), arrange one lead-out piece in the innermost circumferential slot hole on the starting side for accommodating the outer coil pieces and arrange one lead-out piece in the outermost circumferential slot on the other side. before executing the procedure of d), arrange one lead-out piece in the innermost circumferential slot on one side among the slots for accommodating the central coil pieces and arrange one lead-out piece in the outermost circumferential slot on the other side. A method for manufacturing a stator in a rotating electrical machine is characterized by this.

13. In the manufacturing method according to Claim 12, form convex portions or concave portions at the open end portions of the inner coil pieces, the inner coil pieces, the central coil pieces, and the lead-out pieces on the lead-out side, form concave portions or convex portions corresponding to the lead-out side at the open end portions of the inner coil pieces, the inner coil pieces, and the central coil pieces on the opposite lead-out side, A method for manufacturing a stator in a rotating electrical machine is characterized in that the coil pieces are electrically connected by fitting the convex portions and concave portions of the coil pieces on the lead-out side and the opposite lead-out side within the slot holes of the bobbin.

14. In the manufacturing method according to claim 13, it is possible to reverse the order of execution of the assembly procedure in b) and the order of execution of the assembly procedure in c), A method for manufacturing a stator in a rotating electrical machine, characterized in that it is possible to reverse the order of execution of the assembly procedure in f) and the order of execution of the assembly procedure in g).

15. In the manufacturing method according to claim 14, the circumferential length of the coil end of the inner coil piece is shorter than the circumferential length of the coil end of the central coil piece, and the circumferential length of the coil end of the outer coil piece is longer, the central coil piece on the outgoing side and the central coil piece on the non-outgoing side are connected, the inner coil piece on the outgoing side and the outer coil piece on the non-outgoing side are connected, A method for manufacturing a stator in a rotating electrical machine, characterized in that the circumferential lengths of the concentric portions are made uniform by connecting the outer coil piece on the outgoing side and the inner coil piece on the non-outgoing side.

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