Armature, motor, and production method for armature

Abstract

An armature (20) has an armature coil (21K) to which current is applied. The armature coil (21K) has a magnetic flux linkage part (21CS) to which magnetic flux from a mobile element (10) is linked. The direction in which the magnetic flux is linked to the magnetic flux linkage part (21CS) is a first direction (X), the direction of relative movement between the armature (20) and the mobile element (10) is a second direction (Y) that is orthogonal to the first direction (X), and the extension direction of the magnetic flux linkage part (21CS) of the armature coil (21K) is a third direction (Z) that is orthogonal to the first direction (X) and the second direction (Y). The armature coil (21K) comprises a plurality of core pieces (21C) that are arranged side by side in the second direction (Y), and the magnetic flux linkage part (21CS) has a plurality of recesses (21CR) that are recessed in the second direction (Y). At least two of the plurality of recesses (21CR) are provided so as alternate on opposite sides in the second direction (Y) at different positions in the third direction (Z).

Description

Armature, motor, and method for manufacturing an armature 【0007】 , 【0001】 The present disclosure relates to an armature, a motor, and a method for manufacturing an armature. 【0002】 Conventionally, as a coreless motor or a slotless motor without a slot portion, an armature has been proposed in which the conductor width of an armature coil facing a magnet is different from that of other portions via an air gap (see, for example, Patent Document 1). In Patent Document 1, a structure is shown in which a plate-shaped conductor obtained by punching a copper plate called a printed coil is used, and by arbitrarily setting the conductor width with respect to the current conduction direction, the occupation ratio of the coil is improved and the motor can be made to have a higher output. 【0003】 In a coreless motor or a slotless motor without a slot portion, there is a problem that eddy current loss occurs in the coil portion due to magnetic flux linkage, and the efficiency of the motor decreases. In Patent Document 1, for the purpose of improving the efficiency of the motor, a structure is shown in which a slit portion is provided in the magnetic flux linkage portion of the coil and the inner connection piece and the outer connection piece are made into a parallel circuit. 【0004】 By dividing and reducing the conductor width of the portion where the alternating magnetic field links with the coil, the eddy current of the coil is suppressed and the motor is made more efficient. Among various constraint conditions and trade-offs, making the conductor width as large as possible and reducing the armature resistance leads to miniaturization and higher output of the motor. 【0005】 Japanese Patent Application Laid-Open No. 2008-099429 【0006】 Here, the direction in which magnetic flux links with the magnetic flux linkage portion of the coil is defined as the first direction, the direction orthogonal to the first direction and in which the armature and the mover relatively move is defined as the second direction, and the direction orthogonal to the first direction and the second direction and in which the magnetic flux linkage portion of the coil extends is defined as the third direction. 【0007】 In Patent Document 1, with respect to the structure of the magnetic flux linkage portion of the coil without a slit portion, by providing a slit portion along the third direction in which the magnetic flux linkage portion extends, the path through which eddy current flows is divided into two eddy current loss paths. This aims to reduce the amount of linked magnetic flux per path, increase the resistance value of the eddy current path, and reduce the eddy current. 【0008】 However, electromagnetic analysis of the flux linkage section with the slit revealed that eddy current paths actually form around the slit, resulting in little effect from the eddy current reduction. Furthermore, when the slit is formed by press working, it is necessary to punch it out with a straight, plate-shaped punch, which weakens the rigidity of the punch in the direction of the slit width. In order to ensure productivity, the slit width must be increased, which reduces the conductor area of ​​the coil, increases DC copper loss, and worsens efficiency. 【0009】 This disclosure provides technologies to solve the above-mentioned problems, and aims to provide an armature, motor, and a method for manufacturing an armature that are highly productive, highly efficient, compact, and capable of high output. 【0010】 The armature according to this disclosure has an armature coil to which an electric current is applied, the armature coil has a flux linkage portion to which magnetic flux from a movable element links, and when the direction in which the magnetic flux links with the flux linkage portion is defined as the first direction, the direction perpendicular to the first direction in which the armature and the movable element move relative to each other is defined as the second direction, and the direction perpendicular to the first and second directions in which the flux linkage portion of the armature coil extends is defined as the third direction, the armature coil consists of a plurality of coil pieces arranged in the second direction, the flux linkage portion has a plurality of recesses that are recessed in the second direction, and at least two of the plurality of recesses are arranged alternately at different positions in the third direction in the opposite direction to the second direction. The motor according to this disclosure also comprises an armature and a movable element arranged to face each other with an air gap between them. Furthermore, the method for manufacturing an armature according to this disclosure involves punching out the inter-coil slit portion between adjacent coil pieces in the second direction, including the magnetic flux linkage portion, and the plurality of recesses from a single metal plate using the same punch. 【0011】 The armature, motor, and method for manufacturing an armature described herein provide an armature, motor, and method for manufacturing an armature that offer excellent productivity, high efficiency, miniaturization, and high output. 【0012】This is a schematic cross-sectional view of the armature according to Embodiment 1. This is a cross-sectional view taken along line A-A in Figure 1. Figure 3A is a top view of the armature according to Embodiment 1. Figure 3B is a side view of the armature according to Embodiment 1. Figure 3C is a bottom view of the armature according to Embodiment 1. Figure 4A is a wiring diagram of the armature. Figure 4B is a wiring diagram when busbars and terminals are used. Figure 4C is a wiring diagram when individual coils are connected. This is a flowchart of the manufacturing process of the coil according to Embodiment 1. This is a top view of a coil piece in the process of processing according to Embodiment 1. Figure 7A is a schematic diagram showing the path of eddy currents generated at the magnetic flux linkage of the armature coil of the comparative example. Figure 7B is a schematic diagram showing the path of eddy currents generated at the magnetic flux linkage of the armature coil of the second comparative example with a slit. Figure 7C is a schematic diagram showing the path of eddy currents generated at the magnetic flux linkage of the armature coil of the comparative example with a slit. This is a schematic diagram showing the path of eddy currents generated at the magnetic flux linkage of the armature coil according to Embodiment 1. This is a schematic diagram showing the path of eddy currents generated at the magnetic flux linkage of the armature coil of the third comparative example. This is an enlarged view of the circled U portion in Figure 8. This is a schematic diagram showing the configuration of an armature coil formed in a straight, flat plate shape. This is a schematic diagram showing the path of eddy currents generated at the magnetic flux linkage of the armature coil according to Embodiment 2. This is a schematic diagram showing the path of eddy currents generated at the magnetic flux linkage of the armature coil according to Embodiment 3. This is a schematic diagram showing the path of eddy currents generated at the magnetic flux linkage of the armature coil according to Embodiment 4. This is a schematic diagram showing the path of eddy currents generated at the magnetic flux linkage of the armature coil according to Embodiment 5. This is a top view of a coil piece according to Embodiment 1. This is a top view of the coil of the comparative example. This is a top view of a coil piece of the comparative example without a recess. This is a graph calculated by analyzing the eddy current loss generated in a coil piece when the number of recesses and the depth of the recesses in the circumferential direction Y are changed. This is a graph plotting the total copper loss, including the DC copper loss for driving the armature coil. 【0013】Embodiment 1. The armature, motor, and method for manufacturing the armature according to Embodiment 1 will be described below. In the following description, the direction in which the magnetic flux links with the magnetic flux linkage portion of the coil will be referred to as the first direction X, the direction perpendicular to the first direction X in which the armature and the movable part (rotor) move relative to each other will be referred to as the second direction Y, and the direction perpendicular to the first direction X and the second direction Y in which the magnetic flux linkage portion of the armature coil extends will be referred to as the third direction Z. When the first direction X is the axial direction of the motor, it will be referred to as the axial direction X. When the second direction is the circumferential direction of the motor, it will be referred to as the circumferential direction Y. When the third direction Z is the radial direction of the motor, it will be referred to as the radial direction Z. Furthermore, the inside of the axial direction X will be defined as the axial inside side being the center side of the rotor shaft and the opposite side being the axial outside. 【0014】 Figure 1 is a schematic cross-sectional view of a motor 100 (axial gap motor) according to Embodiment 1. It is a schematic cross-sectional view of the motor 100 using an armature 21, and shows only half of the cross-section obtained by cutting the motor 100 with a plane passing through the central axis of the shaft 11 of the rotor 10. Figure 2 is a cross-sectional view obtained by cutting the rotor 10 perpendicular to the axial direction X, and is the A-A cross-sectional view in Figure 1. Figure 2 shows the entire cross-section of the rotor 10. 【0015】 The motor 100 consists of a stator 20 (armature) and a rotor 10 (movable element). The stator 20 has an armature 21, a housing 22 that encloses and holds the armature 21, brackets 23 that cover the openings on both sides of the housing 22 in the axial direction X, and bearings 24 that rotatably support the shaft 11 of the rotor 10. 【0016】 The armature 21 includes an armature coil 21K and a power supply unit 21P that applies current to the armature coil 21K. By applying current to the armature coil 21K, a rotating magnetic field is generated. 【0017】 The rotor 10 comprises a shaft 11 that rotates around a rotation axis Q and outputs driving force to the outside, two disc-shaped rotor cores 12 fitted onto the shaft 11, and a plurality of magnets 13 arranged in the circumferential direction Y on the inner surface of each rotor core 12 in the axial direction X. 【0018】The magnets 13 are magnetized in the depth direction of the paper in Figure 2 (the direction that penetrates the paper: axial direction X), and adjacent magnets 13 in the circumferential direction Y are arranged so that the north pole and south pole alternately reverse in the circumferential direction Y. 【0019】 Figure 3A is a top view of the armature 21. Figure 3B is a side view of the armature 21. Figure 3C is a bottom view of the armature according to Embodiment 1. Figure 4A is a wiring diagram of the armature 21. Figure 4B is a wiring diagram when individual coils are connected. Figure 4C is a wiring diagram when busbar BB and terminal section 21T are used. The armature coil 21K has two layers in the depth direction (axial direction X) of the paper in Figure 3A, and multiple coil pieces 21C are arranged in the circumferential direction Y. In the example of Figure 3A, 72 coil pieces 21C are arranged in each layer. 【0020】 Each coil piece 21C consists of a magnetic flux linkage portion 21CS positioned in the center in the radial direction Z, an outer turn portion 21CTOUT connected to the radially Z-outward side of the magnetic flux linkage portion 21CS, and an inner turn portion 21CTIN connected to the radially Z-inward side of the magnetic flux linkage portion 21CS. The outer joint portion 21C1, which is the radially Z-outward outer end of the outer turn portion 21CTOUT of the first layer coil piece 21C, is joined to the outer joint portion 21C1 of the second layer coil piece 21C. 【0021】 The second coil piece 21C, joined to the outer joint 21C1, passes through the outer turn portion 21CTOUT, the magnetic flux linkage portion 21CS, and the inner turn portion 21CTIN, and is joined to the inner joint portion 21C2 of the first coil piece 21C at the inner end of the inner turn portion 21CTIN in the radial direction Z. The two magnetic flux linkage portions 21CS of the coil piece 21C joined in this way are positioned at 36-degree pitches apart in the circumferential direction Y. 【0022】In this way, coil pieces 21C, which are offset by a 36-degree pitch in the circumferential direction Y, are sequentially joined in the first and second layers to form a wavy-winding armature coil 21K. In this example, it is a distributed winding with two windings per pole per phase, and coils U1, U2, W1, W2, V1, and V2 are arranged in order in the circumferential direction Y. The circuit diagram at this time is shown in Figure 4A. The coils of each layer are joined with a Y connection, and a rotating magnetic field is generated by applying a three-phase AC current to the ends of the coils of each layer using an inverter or the like. Figure 16 is a top view of coil pieces 21C (with different numbers of slits). As shown in Figure 16, the width of the coil piece 21C in the circumferential direction Y changes along the radial direction Z through which the current is carried. This configuration has the effect of increasing the average cross-sectional area when the coil piece 21C is cut perpendicular to the radial direction Z, thereby suppressing the electrical resistance of the armature coil 21K, reducing copper loss, and improving the efficiency of the motor 100. 【0023】 Although the above patterns were described in this document, this disclosure can be applied to any structure in which a rotating magnetic field is generated by a coil, such as short-pitch winding, distributed winding with 1 for each pole and 1 for each phase, or salient-pole concentrated winding, as long as the coils have adjacent structures with different potentials. However, comparing salient-pole concentrated winding and distributed winding, distributed winding makes it easier to match the slot pitch between turns of the armature coil with the magnetic pole pitch, thus increasing the torque constant and resulting in a higher output for the motor 100. 【0024】 Figure 5 is a flowchart showing the manufacturing process of coil pieces 21C and armature coil 21K. Figure 6 is a top view of multiple coil pieces 21C in the process of being manufactured. To manufacture the coil pieces 21C, first, multiple inter-coil piece slits S and multiple recesses 21CR between adjacent coil pieces 21C in the circumferential direction Y, including the magnetic flux linkage portion 21CS, are punched out from a single metal plate 21D (such as a copper plate) using the same punch (step S001: slit punching process). After the slit punching process is completed, the metal plate 21D is in a state where many coil pieces 21C are connected by outer connecting portion 21ROUT and inner connecting portion 21RIN. By having all the coil pieces 21C connected in this way, the metal plate 21D is easier to transport during manufacturing, thus improving the productivity of the product. 【0025】 Furthermore, by providing a positioning section 21H in the outer connecting section 21ROUT, the position of the metal plate 21D in each subsequent process can be accurately positioned, thereby improving the productivity of the product. Next, an insulating film is formed on the surface of the metal plate 21D (Step S002: Insulating Film Forming Process). Methods for attaching the insulating material to the metal plate 21D include electrodeposition coating, powder coating, or covering the entire surface with a mold or the like. 【0026】 After the insulating film formation process, the insulating material is peeled off from the outer joint portion 21C1 on the outer side in the radial direction Z and the inner joint portion 21C2 on the inner side in the radial direction Z (Step S003: Insulating film peeling process). Once the two metal plates 21D have been processed up to this point, the second layer is placed on top of the first layer with its front and back sides reversed, and the outer joint portions 21C1 and inner joint portions 21C2 of both layers are joined together (Step S004: Coil joining process). The power supply portion 21P and busbar BB shown in Figure 3B are also joined. After joining, the inner cutting portion 21EIN, which is located further inward in the radial direction Z of the inner joint portion 21C2, and the outer diameter cutting portion 21EOUT, which is located further outward in the radial direction Z of the outer joint portion 21C1, are cut to separate the outer connecting portion 21ROUT and the inner connecting portion 21RIN (Step S005: Connecting portion separation process) to obtain the armature coil 21K. Although the explanation used an example where the inner connecting portion 21RIN and the outer connecting portion 21ROUT are connected, individually punched coil pieces may also be used. Furthermore, the slit portion S and recess 21CR between the coil pieces may be formed on a single metal plate by etching. Etching allows for the formation of coil pieces 21C with high precision. In addition, by including the recess 21CR in the etched portion, the amount of masking material used to mask the conductor of the coil piece 21C can be reduced, thus reducing the environmental impact. 【0027】Figure 7A is a schematic diagram showing the path of eddy currents generated in the magnetic flux linkage portion 21CSB of the armature coil 21KB of the first comparative example. The dashed arrows in the figure indicate the eddy current path R. Figure 7B is a schematic diagram showing the path of eddy currents generated in the magnetic flux linkage portion 21CSC of the armature coil 21KC of the second comparative example, which is provided with a slit portion SC. The dashed arrows in the figure indicate the eddy current path R. Figure 7C is a schematic diagram showing the path of eddy currents generated in the magnetic flux linkage portion 21CSC of the armature coil 21KC of the second comparative example, which is provided with a slit portion SC. The dashed arrows in the figure indicate the eddy current path R. When the rotor 10 (movable element) rotates, the rotor 10 moves in the circumferential direction Y relative to the armature 21, so the amount of magnetic flux changes in the axial direction X, and eddy currents flow in a direction that opposes this change. This is the basic principle by which eddy current losses occur in the coil. In the case of a core-type motor where the teeth of the iron core are located between the coils in the circumferential direction Y, almost all of the magnetic flux flows within the iron core, so almost no magnetic flux flows through the coil. Therefore, almost no eddy currents are generated in the coil. Furthermore, even if leakage flux occurs instead of magnetic flux flowing through the iron core, the magnetic flux flows from the teeth to the teeth adjacent to the circumferential direction Y. Therefore, the direction of eddy current generation is fundamentally different from that of a coreless motor or a slotless motor without slots, where the magnetic flux flows in the axial direction X. In addition, in the case of a core-type motor, the width of the coil in the circumferential direction Y is relatively smaller due to the space of the iron core, so eddy currents are less likely to occur, but the DC copper loss increases due to the reduction in the cross-sectional area of ​​the coil. In coreless motors or slotless motors without slots, the cross-sectional area of ​​the coil can be increased, but suppressing eddy currents becomes an important issue. 【0028】 To avoid these eddy currents, in the second comparative example, a slit portion SC extending radially Z is provided in the magnetic flux linkage portion 21CSC. By forming the slit portion SC, the eddy current path is divided in the circumferential direction Y as shown in Figure 7B, thereby aiming to suppress eddy currents. Ignoring the reduction in conductor volume due to the slit portion SC and the conductivity of the outer and inner junctions, the conductor is divided into two, resulting in half the flux linkage and double the resistance. Since the induced voltage is halved and the resistance is doubled, the current value becomes 1 / 4. 【0029】 By the way, since Joule loss is proportional to the square of the resistance and current, the eddy loss per conductor is 1 / 8. Since the conductor is divided into two, it becomes 2 × 1 / 8, and theoretically the eddy loss becomes 1 / 4. However, in the structure of Figure 7B, the part other than the slit SC is a single conductive conductor, so in reality, as shown in Figure 7C, an eddy current path R is formed outside the slit SC, and the theoretical eddy loss reduction effect described above cannot be obtained. Figure 17 is a top view of a coil piece 21CD of a comparative example. As shown in Figure 17, let's assume that the slit SD is extended beyond the range of the magnetic flux linkage to the outer junction 21CD1 and the inner junction 21CD2. In this case, although the eddy loss reduction effect is greater, especially in a distributed winding structure, the outer turn portion 21CDTOUT and the inner turn portion 21CDTIN extend in an oblique direction including the radial direction Z and the circumferential direction Y, so the cross-sectional area of ​​the coil piece cut perpendicular to the longitudinal direction in that portion (hereinafter simply referred to as the cross-sectional area) becomes smaller. Thus, when the slit SD is extended in the direction of extension of the coil piece 21CD to the outer joint 21CD1 and the inner joint 21CD2, the cross-sectional area of ​​the coil becomes smaller, and the efficiency of the armature deteriorates. In addition, the narrow section NAIN of the inner turn section 21CDTIN (the joint with the magnetic flux linkage section 21CDS) and the narrow section NAOUT of the outer turn section 21CDTOUT (the joint with the magnetic flux linkage section 21CDS) locally reduce the cross-sectional area of ​​the coil piece 21CD, which increases the heat generation density and may exceed the preset temperature constraints. In particular, in axial gap motors, the cross-sectional area of ​​the narrow section NAIN of the inner turn section 21CDTIN becomes even smaller, making it impossible to increase the output due to temperature constraints. 【0030】Figure 8 is a schematic diagram showing the current path E flowing through the magnetic flux linkage portion 21CS of the armature coil 21K and the eddy current path R generated in the magnetic flux linkage portion 21CS. As shown in Figures 3A, 3B, and 8, on both sides of a single magnetic flux linkage portion 21CS in the circumferential direction Y, four recesses 21CR are arranged in a staggered pattern at different positions in the radial direction Z, indenting in the circumferential direction Y. That is, the direction in which each recess 21CR is indented in the circumferential direction Y is alternately opposite along the radial direction Z and in the circumferential direction Y. Although Figures 3A, 3B, and 8 show an example in which four recesses 21CR are arranged alternately, any number of recesses is acceptable, and it is sufficient that at least two recesses 21CR are arranged alternately in opposite directions in the circumferential direction Y at different positions in the radial direction Z. 【0031】In this way, by alternately providing recesses 21CR that are recessed toward one side of the circumferential direction Y and recesses 21CR that are recessed toward the other side of the circumferential direction Y on both sides of the magnetic flux linkage portion 21CS along the radial direction Z, the path R of eddy currents in the radial direction Z can be blocked in a zigzag pattern, thereby reducing the eddy currents generated in the magnetic flux linkage portion 21CS and enabling high efficiency of the motor 100. As shown in Figure 16, in an armature 21 where the outer coil width 21LOOUT of the magnetic flux linkage portion 21CS of the coil piece 21C is larger than the inner coil width 21LIN, it is desirable that the depth D2 of the outer recess 21CR in the circumferential direction Y is greater than the depth D1 of the inner recess 21CR in the circumferential direction Y. Since eddy currents flow radially in the Z centered on the center of the coil piece 21C in the circumferential direction Y, it is necessary to set the depth of the recess 21CR with respect to the center of the coil piece 21C. When the depth D2 of the outer recess 21CR and the depth D1 of the inner recess 21CR are the same, the circumferential Y distance to the circumferential center line 21CM of the coil piece 21C becomes larger in the outer portion in the radial Z direction, making it difficult to effectively suppress eddy currents. Figure 18 is a top view of a comparative example coil piece 21CB without a recess 21CR. The area indicated by hatching F in Figure 18 is the area where the current density of eddy current loss is large. The area where eddy current loss occurs is larger in the outer portion in the radial Z direction of the coil piece 21CB compared to the inner portion. Therefore, in order to interrupt the eddy current path, as shown in Figure 16, it is effective to set the circumferential Y depth D2 of the outer recess 21CR to be deeper than the circumferential Y depth D1 of the inner recess 21CR. By increasing the circumferential Y depth D2 of the outer recess 21CR, eddy currents can be effectively suppressed, and the efficiency of the motor 100 can be improved. Furthermore, it is desirable that the recess 21CR be provided only in the magnetic flux linkage portion 21CS where the coil piece 21C and the magnet 13 face each other in the axial direction X. Providing the recess 21CR in places other than the magnetic flux linkage portion 21CS has little effect in suppressing the generation of eddy currents. Therefore, providing the recess 21CR only in the magnetic flux linkage portion 21CS effectively improves the efficiency of the motor 100.As shown in Figure 16, when comparing the angle of the inner turn portion 21CTIN with respect to the radial Z and the angle R2 of the outer turn portion 21CTOUT with respect to the radial Z, it is desirable to set the angle R1 of the inner turn portion 21CTIN with respect to the radial Z to be smaller than the angle R2 of the outer turn portion 21CTOUT with respect to the radial Z. With this configuration, the cross-sectional area of ​​the inner turn portion 21CTIN, which has a small cross-sectional area when cut perpendicular to the longitudinal direction, can be increased, thereby reducing the heat generation density of the armature coil 21K and suppressing the maximum temperature in the armature coil 21K, which has the effect of increasing the output of the motor 100. 【0032】 The recess 21CR only locally obstructs the current for driving the armature 21, so the armature 21 can be driven without any problems. The armature coil 21KC of the second comparative example shown in Figure 7B is similar in that it does not obstruct the current for driving the armature, but as described above, in Figure 7B, the outer turn portion 21CTOUT and the inner turn portion 21CTIN are connected as a single unit, so the expected effect cannot be obtained. 【0033】Figure 9 is a schematic diagram showing the current path E flowing through the magnetic flux linkage portion 21CSD of the armature coil 21KD of the third comparative example and the eddy current path R generated in the magnetic flux linkage portion 21CSD. In the third comparative example shown in Figure 9, the recesses 21CR are not alternately arranged on both sides of the magnetic flux linkage portion 21CSD in the Y direction, but are provided only on one side of the magnetic flux linkage portion 21CSD in the Y direction. In this case, a large eddy current path R is formed in the radial direction Z, so the effect of eddy current reduction is diminished. By providing recesses 21CR that alternately open in the circumferential direction Y as in this embodiment, the eddy current path R flowing in the radial direction Z can be effectively blocked, and the motor can be made more efficient. Note that the depth L1 in the circumferential direction Y of the recesses 21CR in Embodiment 1 shown in Figure 8 is preferably more than half of the plate width L2 in the circumferential direction Y of the magnetic flux linkage portion 21CS, especially when the number of recesses 21CR is small. By making the depth L1 more than half the plate width L2, the path R of eddy currents flowing in the radial direction Z is completely blocked when viewed in the radial direction Z, thus effectively reducing eddy loss. Next, the relationship between the number of recesses 21CR, the depth of the recesses 21CR in the circumferential direction Y, and the width of the coil piece 21C in the circumferential direction Y will be explained. Figure 19 is a graph calculated by analyzing the eddy current loss generated in the coil piece 21C when the number of recesses 21CR and the depth of the recesses 21CR in the circumferential direction Y are changed. The horizontal axis shows the ratio of the depth of the recesses 21CR in the circumferential direction Y to the width of the coil in the circumferential direction Y. For comparison, the graph is plotted from no recesses 21CR (0%) to a depth of 75% of the length in the circumferential direction Y. The number of recesses 21CR provided in the magnetic flux linkage section CS is changed depending on the line type. Eddy current loss decreases as the number of recesses 21CR increases and as the depth of the recesses 21CR in the circumferential direction Y increases. On the other hand, it can be seen that as the depth of the recess 21CR in the circumferential direction Y increases, the slope of the graph becomes smaller and saturates. Figure 20 is a graph plotting the total copper loss, including DC copper loss, for driving the armature coil 21K. The horizontal axis and line type are the same as in Figure 19. As shown in Figure 20, when the depth of the recess 21CR in the circumferential direction Y increases, eddy currents are suppressed, but the DC copper loss increases even more, resulting in a larger total loss. It can also be seen that there is a local minimum point where the total loss is minimized for a given depth of the recess 21CR in the circumferential direction Y.Therefore, it is desirable that the depth of the recess 21CR in the circumferential direction Y be in the range of 25% to 75% of the width of the coil piece 21C in the circumferential direction Y. By setting it within this range, the total loss can be minimized by balancing the DC copper loss and the coil's eddy loss, which has the effect of increasing the efficiency of the motor 100. Also, it is desirable that there be a large number of recesses 21CR. If L is the length in the radial direction Z of the magnetic flux linkage section 21CS, B is the average width in the circumferential direction Y of the coil piece 21C, N is the number of recesses 21CR, and P is the recess pitch, which is the length between recesses 21CR arranged in the radial direction, then P can be calculated by the following equation: P = L / N Also, it is desirable that the relationship between P and B is as follows: P < B Combining both conditions, L / N < B. If there are no recesses 21CR, the eddy current path is longer in the radial direction Z than in the circumferential direction Y, resulting in eddy currents being generated along a long path and a decrease in motor efficiency. By setting the coil pitch and the average circumferential Y width of the coil piece 21C to P < B, the path of eddy currents generated in the radial Z direction is blocked, and the eddy current path in the radial Z direction can be made shorter than the eddy current path in the circumferential Y direction. This effectively suppresses eddy currents and improves the efficiency of the motor 100. 【0034】 As shown in Figure 6, assuming that the slit portion S between the coil pieces is processed by press working, the shape transferred from the slit portion S becomes the punch shape in the die. To reduce copper loss, it is desirable to reduce the width of the slit portion S between the coil pieces. However, simply reducing the width of the slit portion S reduces the thickness of the punch in the circumferential direction Y, making it impossible to secure the necessary rigidity of the punch, resulting in reduced productivity such as punch breakage. If the width of the slit portion S between the coil pieces is increased to secure the necessary rigidity of the punch, then the conductive area of ​​the coil piece 21C decreases, worsening copper loss and reducing the efficiency of the motor 100. 【0035】 In this disclosure, the punch used to punch out the slit portion S between coil pieces is provided with a projection that protrudes in the circumferential direction Y for punching out the recess 21CR which is continuous with the slit portion S between coil pieces. Therefore, the rigidity of the punch in the circumferential direction Y when punching out the slit portion S between coil pieces is improved, which has the effect of improving the productivity of the product. 【0036】 By providing the punch with a protrusion that extends in the circumferential direction Y to ensure the rigidity of the punch, the width of the slit portion S between the coil pieces can be reduced, thereby increasing the conductor area of ​​the coil piece 21C, reducing copper loss, and achieving high efficiency of the motor 100. 【0037】 Figure 10 is an enlarged view of the circled area U in Figure 8. Because the potential difference between the magnetic flux linkage portions 21CS of adjacent armature coils 21K in the circumferential direction Y is different, an electric field is generated in the slit portion S between the coil pieces, and if the electric field exceeds a certain threshold, there is a risk of partial discharge occurring between the two magnetic flux linkage portions 21CS. In particular, since the electric field is concentrated at the edge of the conductor, it is known that partial discharge will occur starting from the vicinity of the edge. 【0038】 Therefore, the edges of the opening 21CRY of the recess 21CR in this embodiment 1 are given a rounded edge (R-shaped). By rounding the edges of the opening 21CRY, the electric field concentration that occurs between adjacent coil pieces 21C in the circumferential direction Y can be mitigated, thereby improving insulation against partial discharge. 【0039】 Furthermore, when punching out the coil inter-slit portion S with a punch, providing an R-shaped section reduces stress concentration in the punch, improves the punch's lifespan, and enhances product productivity. It is also desirable to apply an R-shape to the innermost corner 21CRIN of the recess 21CR. Applying an R-shape to the innermost corner 21CRIN of the recess 21CR reduces stress concentration when punching out the coil inter-slit portion S from the metal plate 21D using a punch, improves the punch's lifespan, and enhances product productivity. 【0040】 Furthermore, by providing a recess 21CR in the magnetic flux linkage portion 21CS that is recessed in the circumferential direction Y, the surface area of ​​the conductor portion in the magnetic flux linkage portion 21CS can be increased, which has the effect of improving the heat dissipation of the armature coil 21K. 【0041】Figure 11 is a schematic diagram showing the configuration of an armature coil 21KR formed in a straight, flat shape. The recess 21CR is not shown. Up until now, the disc-shaped armature coil 21K has been described using an axial gap motor as an example for the motor 100, but the same effect can be obtained even with a linear motor using an armature coil 21KR formed in a flat shape as shown in Figure 11. In the case of a linear motor, the second direction Y becomes straight. In axial gap motors or linear motors, the armature coil can be configured in a planar manner, which has the effect of improving the productivity of the motor. 【0042】 Furthermore, by rolling the armature coil 21KR shown in Figure 11 into a cylindrical shape, the same effect can be obtained even in radial gap motors (slotless motors) that use cylindrical armature coils. Also, although the armature coil 21K has been described as having a two-layer configuration, it is also possible to stack two two-layer coils to make a four-layer structure. Reducing the thickness of the coil reduces the skin effect and eddy loss in the coil, which has the effect of increasing the efficiency of the motor. In addition, it is possible to change the design to parallel connection or delta connection as needed. 【0043】 In this embodiment 1, an example of application to an armature without a core was described, but it can also be applied to the armature of a slotless motor that has only a back yoke and no slots. 【0044】According to the armature, motor, and method for manufacturing the armature according to Embodiment 1, the armature has an armature coil to which current is applied, the armature coil has a magnetic flux linkage portion to which magnetic flux from a movable element links, the direction in which the magnetic flux links with the magnetic flux linkage portion is defined as the first direction, the direction perpendicular to the first direction in which the armature and the movable element move relative to each other is defined as the second direction, and the direction perpendicular to the first and second directions in which the magnetic flux linkage portion of the armature coil extends is defined as the third direction, the armature coil consists of a plurality of coil pieces arranged in the second direction, the magnetic flux linkage portion has a plurality of recesses that are recessed in the second direction, and at least two of the plurality of recesses are arranged alternately at different positions in the third direction in the opposite direction to the second direction, so that an armature can be provided that is highly productive, highly efficient, compact, and capable of high output. Furthermore, since the depth of the recess in the second direction is more than half the width of the magnetic flux linkage portion in the second direction, the path R of the eddy currents flowing in the radial direction Z is completely blocked when viewed in the radial direction Z, thus effectively reducing eddy loss. In addition, since the edges of the openings of the recesses are rounded, the electric field concentration that occurs between adjacent coil pieces 21C in the circumferential direction Y can be mitigated, thus improving insulation against partial discharge. Moreover, since the inter-coil slit portion between adjacent coil pieces in the second direction, including the magnetic flux linkage portion, and the multiple recesses are punched out from a single metal plate with the same punch, the punch that punches out the inter-coil slit portion S is provided with a protrusion that projects in the circumferential direction Y for punching out the recesses 21CR that are continuous with the inter-coil slit portion S. Therefore, the rigidity of the punch in the circumferential direction Y when punching out the inter-coil slit portion S is improved, which has the effect of improving the productivity of the product. Furthermore, since the inter-coil slit portion between adjacent coil pieces in the second direction, including the magnetic flux linkage portion, and the multiple recesses are etched from a single metal plate, the coil pieces 21C can be formed with high precision, providing an armature that is highly efficient, compact, and capable of high output. In addition, by including the recesses 21CR in the etched portion, the amount of masking material used to mask the conductors of the coil pieces 21C can be reduced, thus reducing the environmental impact.In addition, since the width of the armature coil in the second direction changes along the current conduction path, it has the effect of increasing the average cross-sectional area obtained by cutting the coil piece 21C perpendicularly to the radial direction Z. Therefore, it suppresses the electrical resistance of the armature coil 21K to reduce copper loss, and has the effect of improving the efficiency of the motor 100. Also, since the depth of the recess in the second direction is in the range of 25% or more and 75% or less with respect to the width of the coil piece in the second direction including the magnetic flux linkage portion, it is possible to obtain an inflection point of the total loss based on the balance between the DC copper loss and the eddy current loss of the coil. Therefore, it has the effect of improving the efficiency of the motor 100. Also, when the length of the magnetic flux linkage portion of the coil piece in the third direction is L, the average width of the coil piece in the second direction is B, and the number of recesses is N, L / N < B. Thus, it blocks the path of the eddy current generated in the radial direction Z and can shorten the eddy current path in the radial direction Z compared to the eddy current path in the circumferential direction Y. Therefore, it effectively suppresses the eddy current and has the effect of improving the efficiency of the motor 100. In addition, since the armature coil has a distributed winding structure, it is easy to match the pitch between the slots of the armature coil with the pole pitch, and the torque constant can be increased. Therefore, it has the effect of increasing the output of the motor. Also, since the angle of the inner turn portion connected to the inner side of the magnetic flux linkage portion in the third direction with respect to the third direction is smaller than the angle of the outer turn portion connected to the outer side of the magnetic flux linkage portion in the third direction with respect to the third direction, it is possible to increase the cross-sectional area of the inner turn portion 21CTIN having a small cross-sectional area when cut perpendicularly to the longitudinal direction. Therefore, it reduces the heat generation density of the armature coil 21K and can suppress the maximum temperature in the armature coil 21K. Thus, it has the effect of increasing the output of the motor 100. 【0045】 Embodiment 2. Hereinafter, an armature, a motor, and a method for manufacturing an armature according to Embodiment 2 will be described centering on the parts different from Embodiment 1. FIG. 12 is a schematic diagram showing a path R of eddy current generated in a magnetic flux linkage portion 221CS of an armature coil 221K according to Embodiment 2. It corresponds to FIG. 8 of Embodiment 1. 【0046】A recess 221CR that is recessed in the circumferential direction Y is arranged in the magnetic flux interlinking portion 221CS in the same manner as in the first embodiment. The width in the radial direction Z of the opening 221CRY of the recess 221CR is larger than the width in the radial direction Z of the bottom portion that is recessed in the circumferential direction Y of the recess 221CR, and the width in the radial direction Z gradually becomes narrower in a tapered shape from the opening 221CRY of the recess 221CR toward the bottom portion. 【0047】 According to the armature according to the second embodiment, since the width in the third direction of the opening of the recess is larger than the width in the third direction of the bottom portion of the recess, the amount of copper can be reduced without hindering the current flowing in the radial direction Z, so there is an effect of reducing the weight of the armature coil 221K. 【0048】 Also, when punching the slit portion S between coil pieces with a punch, the portion corresponding to the convex portion of the punch for punching the recess 221CR becomes a rib of the punch, so that the rigidity in the circumferential direction Y of the punch when punching the slit portion S between coil pieces is improved, and there is an effect of improving the productivity of the product. 【0049】 Embodiment 3. Hereinafter, the armature, motor, and method for manufacturing an armature according to the third embodiment will be described focusing on the parts different from the second embodiment. FIG. 13 is a schematic diagram showing the path R of eddy current generated in the magnetic flux interlinking portion 321CS of the armature coil 321K according to the third embodiment. It corresponds to FIG. 12 of the second embodiment. As shown in FIG. 13, convex portions 321CP of magnetic flux interlinking portions 321CS adjacent to each other in the circumferential direction Y project into the recess 221CR formed in the second embodiment. The magnetic flux interlinking portion 321CS alternately includes a recess 221CR that is recessed in one direction in the circumferential direction Y and a convex portion 321CP that projects in the other direction in the circumferential direction Y along the radial direction Z. 【0050】 According to the armature according to the third embodiment, the magnetic flux interlinking portion alternately includes the recess that is recessed in one direction in the second direction and the convex portion that projects in the other direction in the second direction along the third direction, and the convex portion of the magnetic flux interlinking portion adjacent to each other in the second direction is arranged in the recess. Therefore, by arranging the convex portion 321CP of the coil piece 321C adjacent to the recess 221CR in the circumferential direction Y as a conductor portion, there is an effect of reducing the electrical resistance value of the conductor in the radial direction Z. 【0051】 Embodiment 4. Hereinafter, the armature, motor, and method for manufacturing the armature according to Embodiment 4 will be described, focusing on the parts that differ from Embodiment 1. Figure 14 is a schematic diagram showing the path of eddy currents generated in the magnetic flux linkage portion 421CS of the armature coil 421K according to Embodiment 4. As shown in Figure 14, compared to the magnetic flux linkage portion 21CS described in Embodiment 1, the magnetic flux linkage portion 421CS of Embodiment 4 has a slit portion S4 extending in the radial direction Z at the center in the circumferential direction Y, and the magnetic flux linkage portion 421CS is divided into a first magnetic flux linkage portion 421CS1 and a second magnetic flux linkage portion 421CS2 by the slit portion S4. 【0052】 The shapes of the circumferential Y-shaped sides of the first magnetic flux linkage portion 421CS1 and the second magnetic flux linkage portion 421CS2 are the same as the shapes of the circumferential Y-shaped sides of the magnetic flux linkage portion 21CS in Embodiment 1. Therefore, the first magnetic flux linkage portion 421CS1 and the second magnetic flux linkage portion 421CS2 are provided with recesses 421CR that are alternately recessed in opposite directions in the circumferential Y direction along the radial Z direction. 【0053】 According to the armature of Embodiment 4, the flux linkage portion extends in the third direction and is provided with a slit portion that divides the flux linkage portion into a first flux linkage portion and a second flux linkage portion. The first flux linkage portion and the second flux linkage portion each have the recess. As a result, the width in the circumferential direction Y of the first flux linkage portion 421CS1 and the second flux linkage portion 421CS2 is reduced, and the recess 321CR can more finely block the path R of eddy currents flowing in the radial direction Z of the first flux linkage portion 421CS1 and the second flux linkage portion 421CS2, thereby reducing eddy currents and achieving the effect of increasing the efficiency of the motor 100. 【0054】Embodiment 5. Hereinafter, the armature, motor, and method for manufacturing the armature according to Embodiment 5 will be described, focusing on the differences from Embodiment 3. Figure 15 is a schematic diagram showing the path of eddy currents generated in the magnetic flux linkage portion 521CS of the armature coil 521K according to Embodiment 5. As shown in Figure 15, compared to the magnetic flux linkage portion 321CS described in Embodiment 3, the magnetic flux linkage portion 521CS of Embodiment 5 is provided with a slit portion S5 that extends in a zigzag pattern in the radial direction Z, and the magnetic flux linkage portion 521CS is divided into a first magnetic flux linkage portion 521CS1 and a second magnetic flux linkage portion 521CS2 by the slit portion S5. 【0055】 The shapes of the circumferential Y-side surfaces of the first magnetic flux linkage portion 521CS1 and the second magnetic flux linkage portion 521CS2 are the same as the shapes of the circumferential Y-side surfaces of the magnetic flux linkage portion 321CS in Embodiment 3. Therefore, the first magnetic flux linkage portion 521CS1 and the second magnetic flux linkage portion 521CS2 each alternately have recesses 521CR that are recessed in one direction in the circumferential Y and protrusions 521CP that are projected in the other direction in the circumferential Y, along the radial Z direction. 【0056】 According to the armature of Embodiment 5, the magnetic flux linkage portion extends in the third direction and is provided with a slit portion that divides the magnetic flux linkage portion into a first magnetic flux linkage portion and a second magnetic flux linkage portion. The first magnetic flux linkage portion and the second magnetic flux linkage portion each have the convex portion. As a result, the width of the coil piece 521C in the circumferential direction Y is reduced, and the recess 521CR and the convex portion 521CP can more finely block the path R of eddy currents flowing in the radial direction Z through the first magnetic flux linkage portion 521CS1 and the second magnetic flux linkage portion 521CS2, thereby reducing eddy currents and achieving the effect of increasing the efficiency of the motor 100. 【0057】While this disclosure describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but are applicable individually or in various combinations to the embodiments. Accordingly, countless variations not illustrated are envisioned within the scope of the art disclosed in this specification. For example, these include modifying, adding or omitting at least one component, or extracting at least one component and combining it with a component from another embodiment. 【0058】 100 Motor, 10 Rotor, 11 Shaft, 12 Rotor core, 13 Magnet, 20 Stator, 21 Armature, 21C, 21CB, 21CD, 321C, 521C Coil piece, 21C1, 21CD1 Outer joint, 21C2, 21CD2 Inner joint, 21CR, 221CR, 321CR, 421CR, 521CR Recess, 21CRIN Corner, 21CRY Opening, 21CS, 21CSB, 21CSC, 21CSD, 221CS, 321CS, 421CS, 521CS Magnetic flux linkage, 421CS1, 521CS1 First magnetic flux linkage, 421CS2, 521CS2 Second flux linkage section, 21CTIN, 21CDTIN Inner turn section, 21CTOUT, 21CDTOUT Outer turn section, 21D Metal plate, 21EIN Inner cut section, 21EOUT Outer diameter cut section, 21H Positioning section, 21K, 21KB, 21KC, 21KD, 21KR, 221K, 321K, 421K, 521K Armature coil, 21CM Center line, 21P Power supply section, 221CRY Opening, 21RIN Inner connection section, 21ROUT Outer connection section, 21T Terminal section, 22 Housing, 23 Bracket, 24 Bearing, 321CP, 521CP Protrusion, BB Busbar, Q Rotation axis, S Slit section between coil pieces, S4, S5, SC Slit section, X Axial direction (first direction), Y circumferential direction (second direction), Z radial direction (third direction), F hatching, NAIN, NAUTH narrow section, D1, D2 depth.

Claims

1. An armature having an armature coil to which an electric current is applied, wherein the armature coil has a flux linkage portion to which magnetic flux from a movable element links, and the direction in which the magnetic flux links with the flux linkage portion is defined as the first direction, the direction perpendicular to the first direction in which the armature and the movable element move relative to each other is defined as the second direction, and the direction perpendicular to the first and second directions in which the flux linkage portion of the armature coil extends is defined as the third direction, wherein the armature coil consists of a plurality of coil pieces arranged in the second direction, the flux linkage portion has a plurality of recesses that are recessed in the second direction, and at least two of the plurality of recesses are alternately arranged at different positions in the third direction in the opposite direction to the second direction.

2. The armature according to claim 1, wherein the width of the opening of the recess in the third direction is greater than the width of the bottom of the recess in the third direction.

3. The armature according to claim 1 or 2, wherein the magnetic flux linkage portion alternately comprises recesses that are recessed in one direction of the second direction and protrusions that are projected in the other direction of the second direction, and the protrusions of adjacent magnetic flux linkage portions in the second direction are arranged in the recesses.

4. The armature according to any one of claims 1 to 3, wherein the magnetic flux linkage portion extends in the third direction and is provided with a slit portion that divides the magnetic flux linkage portion into a first magnetic flux linkage portion and a second magnetic flux linkage portion, and the first magnetic flux linkage portion and the second magnetic flux linkage portion each provide the recess.

5. The armature according to claim 3, wherein the magnetic flux linkage portion extends in the third direction and is provided with a slit portion that divides the magnetic flux linkage portion into a first magnetic flux linkage portion and a second magnetic flux linkage portion, and the first magnetic flux linkage portion and the second magnetic flux linkage portion each have the convex portion.

6. The armature according to any one of claims 1 to 5, wherein the depth of the recess in the second direction is more than half the width of the magnetic flux linkage portion in the second direction.

7. The armature according to any one of claims 1 to 6, wherein the edge of the opening of the recess is rounded.

8. The armature according to any one of claims 1 to 7, wherein the armature is an armature without a core, or an armature having only a back yoke portion and no slot portion.

9. The armature according to any one of claims 1 to 8, wherein the width of the armature coil in the second direction changes along the current path.

10. The armature according to any one of claims 1 to 9, wherein the depth of the recess in the second direction is in the range of 25% or more and 75% or less of the width of the coil piece including the magnetic flux linkage portion in the second direction.

11. The armature according to any one of claims 1 to 10, wherein L is the length in the third direction of the magnetic flux linkage portion of the coil piece, B is the average width of the coil piece in the second direction, and N is the number of recesses, and L / N < B.

12. The armature according to any one of claims 1 to 11, wherein the armature coil has a distributed winding structure.

13. The armature according to any one of claims 1 to 12, wherein the angle of the inner turn portion connected to the inside of the third direction of the magnetic flux linkage portion with respect to the third direction is smaller than the angle of the outer turn portion connected to the outside of the third direction of the magnetic flux linkage portion with respect to the third direction.

14. A motor comprising an armature according to any one of claims 1 to 13 and a movable element arranged to face it with an air gap between them.

15. The motor according to claim 14, wherein the motor is an axial gap motor, a radial gap motor, or a linear motor.

16. A method for manufacturing an armature according to any one of claims 1 to 13, wherein the same punch is used to punch out the inter-coil slit portion between adjacent coil pieces in the second direction including the magnetic flux linking portion, and the plurality of recesses from a single metal plate.

17. A method for manufacturing an armature according to any one of claims 1 to 13, comprising etching a single metal plate to form inter-coil slits between adjacent coil pieces in the second direction including the magnetic flux linkage portion, and a plurality of recesses.

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