Method for manufacturing laminated iron core and heating device

Abstract

The present disclosure describes a method for manufacturing a laminated iron core and a heating device capable of suppressing deformation occurring in the laminated iron core when heating the laminated iron core.SOLUTION: The method for manufacturing a laminated iron core includes arranging N (N is a natural number of 2 or more) heating units in the laminated iron core such that the N heating units are arranged in a circumferential direction of the laminated iron core, and heating N regions of the laminated iron core, which the N heating units face, by the N heating units. Heating by the N heating units includes switching the operation of the N heating units by one or more and less than N.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a manufacturing method of a laminated iron core and a heating device. [Background technology]

[0002] Patent Document 1 discloses a method of annealing the inner peripheral portion of a laminated core by arranging a heater in a through hole extending along the central axis of the laminated core to heat the laminated core. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-187174 Summary of the Invention [Problem to be solved by the invention]

[0004] According to the method of Patent Document 1, the entire inner periphery of the laminated core is heated at approximately the same time. As a result, although the inner periphery attempts to thermally expand radially outward, the thermal expansion of the inner periphery is hindered because the outer periphery of the laminated core is not heated. As a result, there is no escape route for deformation due to thermal expansion in the inner periphery, and deformations such as warping and undulations can occur in the inner periphery in the lamination direction of the laminated core. A similar phenomenon can occur when the entire outer periphery of the laminated core is heated at approximately the same time.

[0005] Therefore, the present disclosure describes a manufacturing method and a heating device for a laminated core that can suppress deformation that occurs in the laminated core when the laminated core is heated. [Means for solving the problem]

[0006] An example of a manufacturing method for a laminated core includes arranging N heating parts (where N is a natural number of 2 or greater) on the laminated core so that the N heating parts are lined up in the circumferential direction of the laminated core, and heating N regions of the laminated core that face the N heating parts with the N heating parts. Heating with the N heating parts includes switching the operation of the N heating parts one or more times but less than N times at a time. [Effects of the Invention]

[0007] According to the manufacturing method and heating device for a laminated core according to the present disclosure, it is possible to suppress deformation that occurs in the laminated core when the laminated core is heated. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing an example of a laminated core. [Figure 2] FIG. 2 is a top view showing an example of the laminated core and heating device of FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 4 is a top view for explaining an example of the timing of heating the laminated core by the heating unit. [Figure 5] FIG. 5 is a top view for explaining an example of the timing of heating the laminated core by the heating unit. [Figure 6] FIG. 6 is a graph showing an example of the change in temperature over time at three different locations in the laminated core. [Figure 7] Figure 7(a) is a graph that schematically shows an example of the intermittent heating and switching of one heating unit, and Figure 7(b) is a graph that schematically shows an example of the intermittent heating and switching of another heating unit that operates at a different timing from the one heating unit. [Figure 8] FIG. 8 is a top view showing another example of the laminated core and heating device of FIG. [Figure 9] FIG. 9 is a top view for explaining another example of the timing of heating the laminated core by the heating unit. DETAILED DESCRIPTION OF THE INVENTION

[0009] In the following description, the same elements or elements having the same functions will be designated by the same reference numerals, and redundant explanations will be omitted. Note that in this specification, when referring to the top, bottom, right, and left of a figure, the directions of the reference numerals in the figure will be used as the reference.

[0010] [Laminated core configuration] First, the configuration of a laminated core 1 will be described with reference to Fig. 1. Fig. 1 illustrates a stator laminated core as an example of the laminated core 1. The stator laminated core is a part of a stator. The stator is a stator laminated core with windings attached thereto. The stator is combined with a rotor to form a motor.

[0011] The laminated core 1 has an overall cylindrical shape. A central hole 1a is provided in the central portion of the laminated core 1, penetrating the laminated core 1 so as to extend along the central axis Ax. The central hole 1a extends in the height direction (stacking direction) of the laminated core 1. A rotor can be placed inside the central hole 1a.

[0012] The laminated core 1 is a laminated body in which a plurality of punched members W are stacked. The punched members W are, for example, plate-like bodies obtained by punching strip-shaped electromagnetic steel sheets (metal sheets) into a predetermined shape. The laminated core 1 may be formed by rolling a plurality of punched members W. "Rolling" refers to stacking a plurality of punched members W while shifting the angles between the punched members W relative to each other. Rolling is performed primarily for the purpose of offsetting the thickness deviation of the punched members W and improving the flatness, parallelism, and squareness of the laminated core 1. The rolling angle may be set to any value.

[0013] The laminated core 1 includes a yoke portion 2, a plurality of teeth 3, and a plurality of joints 4. The yoke portion 2 is annular and extends to surround the central axis Ax. As illustrated in FIG. 1, the yoke portion 2 may be annular. The plurality of teeth 3 extend radially from the inner edge of the yoke portion 2 toward the central axis Ax. In other words, the plurality of teeth 3 protrude from the inner edge of the yoke portion 2 toward the central axis Ax. The plurality of teeth 3 may be arranged at approximately equal intervals in the circumferential direction of the yoke portion 2. Slots 5, which are spaces for arranging windings (not shown), are defined between adjacent teeth 3.

[0014] The joints 4 may be provided on the yoke portion 2, on each tooth portion 3, or on both the yoke portion 2 and each tooth portion 3. In the example of FIG. 1, as an example of the joints 4, a crimp 4a is provided on the yoke portion 2 and an adhesive 4b is provided on each tooth portion 3. Therefore, adjacent punched members W in the height direction are joined by the crimp 4a and the adhesive 4b. Note that the yoke portion 2 and each tooth portion 3 may both be joined by the crimp 4a. The yoke portion 2 and each tooth portion 3 may both be joined by the adhesive 4b.

[0015] [Heating device configuration] 2 to 6, the configuration of the heating device 10 that heats the laminated core 1 will be described. The heating device 10 is configured to remove strain remaining inside the punched member W by heating the laminated core 1 at a predetermined temperature (e.g., about 700°C to 900°C) for a predetermined cumulative time (e.g., about 1 minute to 120 minutes).

[0016] The heating device 10 includes N (where N is a natural number of 2 or more) heating sections 12 and a controller Ctr (control section). In the example of Fig. 2, the N heating sections 12 include eight heating sections 12A to 12H. In the following, an example will be described in which the heating device 10 includes eight heating sections 12A to 12H.

[0017] 2, the heating portions 12A to 12H have an overall annular (for example, circular) shape when all are combined. The outer diameter of the combined heating portions 12A to 12H is set to be smaller than the inner diameter of the central hole 1a of the laminated core 1. Each of the heating portions 12A to 12H may have a fan shape when viewed from above.

[0018] 2 and 3, the heating portions 12A to 12H are configured to heat the inner periphery of the laminated core 1 while being disposed within the central hole 1a of the laminated core 1. Specifically, the heating portions 12A to 12H are configured to heat the regions R1 to R8 that face each other in the inner periphery of the laminated core 1, respectively. That is, the number of regions in the inner periphery of the laminated core 1 is the same as the number of heating portions 12 provided in the heating device 10. One region of the inner periphery of the laminated core 1 that faces one heating portion 12 may include mainly one tooth portion 3, or may include multiple tooth portions 3. In the example of FIG. 2, each of the regions R1 to R8 mainly includes one tooth portion 3.

[0019] The heating units 12A to 12H are not particularly limited as long as they can heat the inner peripheral portion of the laminated core 1 to a predetermined temperature (for example, about 700°C to 900°C). The heating units 12A to 12H may include, for example, a heating element that can raise the temperature to a predetermined temperature (for example, about 850°C) in a predetermined time (for example, within 0.5 seconds to 300 seconds). The heating element may be, for example, a nichrome resistance heater or a carbon heater. The heating units 12A to 12H may be configured to heat the inner peripheral portion of the laminated core 1 by spraying gas (for example, nitrogen) heated by the heating element onto the inner peripheral portion of the laminated core 1.

[0020] The controller Ctr is configured to generate instruction signals for operating the heating units 12A to 12H based on, for example, a program recorded on a recording medium (not shown) or an operation input from an operator, etc. The controller Ctr is configured to transmit the generated instruction signals to the heating units 12A to 12H.

[0021] The controller Ctr is configured to operate the heating units 12A to 12H at different timings when the heating units 12A to 12H are arranged in the center hole 1a of the laminated core 1 so as to be aligned in the circumferential direction of the laminated core 1. As a result, the regions R1 to R8 are individually heated by the heating units 12A to 12H at different timings. For example, as illustrated in FIG. 7(a), after one of the heating units 12A to 12H is operated, another heating unit different from the one heating unit may be operated among the heating units 12A to 12H, as illustrated in FIG. 7(b).

[0022] There are no particular limitations on the timing for switching between the heating units 12A to 12H, but when the heating device 10 includes four or more heating units 12, the controller Ctr may operate one heating unit 12 and then operate another heating unit 12 that is not adjacent to the one heating unit 12. Alternatively, the controller Ctr may operate one heating unit 12 and then operate another heating unit 12 that faces the one heating unit 12 across the central axis Ax.

[0023] 4 and 5, an example of the timing for switching the heating units 12A to 12H will be described. First, as shown in FIG. 4(a), the controller Ctr operates the heating unit 12A and stops the other heating units 12B to 12H. As a result, the region R1 of the inner circumferential portion of the laminated core 1 is heated, but the other regions R2 to R8 are not heated. Therefore, the thermal expansion of the teeth 3 included in the region R1 in the circumferential direction and radially outward is absorbed by the other regions R2 to R8.

[0024] After a predetermined time (e.g., 0.5 to 50 seconds) has elapsed since the start of operation of the heating unit 12A, the controller Ctr operates the heating unit 12E and stops the other heating units 12A to 12D and 12F to 12H, as illustrated in FIG. 4(b). As a result, the region R5 of the inner circumferential portion of the laminated core 1 is heated, but the other regions R1 to R4 and R6 to R8 are not heated. Therefore, the circumferential and radial outward thermal expansion of the teeth 3 included in region R5 is absorbed by the other regions R1 to R4 and R6 to R8. Furthermore, since region R5 is located on the opposite side of the central axis Ax from region R1, which was heated before heating of region R5 began, region R5 is less susceptible to the influence of thermal expansion in region R1, even if heat remains in region R1.

[0025] After a predetermined time (e.g., 0.5 to 50 seconds) has elapsed since the start of operation of the heating unit 12E, the controller Ctr operates the heating unit 12G and stops the other heating units 12A to 12F and 12H, as illustrated in FIG. 4(c). As a result, the region R7 of the inner circumferential portion of the laminated core 1 is heated, but the other regions R1 to R6 and R8 are not heated. Therefore, the circumferential and radial outward thermal expansion of the teeth 3 included in region R7 is absorbed by the other regions R1 to R6 and R8. Furthermore, since region R7 is located 45° away from region R5, which was heated before the start of heating of region R7, region R7 is less susceptible to the influence of the thermal expansion of region R5, even if heat remains in region R5.

[0026] After a predetermined time (e.g., 0.5 to 50 seconds) has elapsed since the start of operation of the heating unit 12G, the controller Ctr operates the heating unit 12C and stops the other heating units 12A, 12B, 12D to 12H, as illustrated in FIG. 4(d). As a result, the region R3 of the inner circumferential portion of the laminated core 1 is heated, but the other regions R1, R2, R4 to R8 are not heated. Therefore, the circumferential and radial outward thermal expansion of the teeth 3 included in region R3 is absorbed by the other regions R1, R2, R4 to R8. Furthermore, since region R3 is located on the opposite side of the central axis Ax from region R7, which was heated before the start of heating of region R3, region R3 is less susceptible to the influence of thermal expansion in region R7, even if heat remains in region R7.

[0027] After a predetermined time (e.g., 0.5 to 50 seconds) has elapsed since the start of operation of the heating unit 12C, the controller Ctr operates the heating unit 12H and stops the other heating units 12A to 12G, as illustrated in FIG. 5(a). As a result, the region R8 of the inner circumferential portion of the laminated core 1 is heated, but the other regions R1 to R7 are not heated. Therefore, the circumferential and radial outward thermal expansion of the teeth 3 included in region R8 is absorbed by the other regions R1 to R7. Furthermore, since region R8 is located 135° around the central axis Ax from region R3, which was heated before heating of region R8 began, region R8 is less susceptible to the influence of thermal expansion in region R3, even if heat remains in region R3.

[0028] After a predetermined time (e.g., 0.5 to 50 seconds) has elapsed since the start of operation of the heating unit 12H, the controller Ctr operates the heating unit 12D and stops the other heating units 12A to 12C and 12E to 12H, as illustrated in FIG. 5(b). As a result, the region R4 of the inner circumferential portion of the laminated core 1 is heated, but the other regions R1 to R3 and R5 to R8 are not heated. Therefore, the circumferential and radial outward thermal expansion of the teeth 3 included in region R4 is absorbed by the other regions R1 to R3 and R5 to R8. Furthermore, since region R4 is located on the opposite side of the central axis Ax from region R8, which was heated before heating of region R4 began, region R4 is less susceptible to the influence of thermal expansion in region R8, even if heat remains in region R8.

[0029] After a predetermined time (e.g., 0.5 to 50 seconds) has elapsed since the start of operation of the heating unit 12D, the controller Ctr operates the heating unit 12B and stops the other heating units 12A, 12C to 12H, as illustrated in FIG. 5(c). As a result, the region R2 of the inner circumferential portion of the laminated core 1 is heated, but the other regions R1, R3 to R8 are not heated. Therefore, the circumferential and radial outward thermal expansion of the teeth 3 included in region R2 is absorbed by the other regions R1, R3 to R8. Furthermore, region R2 is located 45° away from region R4, which was heated before heating of region R2, around the central axis Ax. Therefore, even if heat remains in region R4, region R2 is less susceptible to the influence of the thermal expansion in region R4.

[0030] After a predetermined time (e.g., 0.5 to 50 seconds) has elapsed since the start of operation of the heating unit 12B, the controller Ctr activates the heating unit 12F and stops the other heating units 12A to 12E, 12G, and 12H, as illustrated in FIG. 5(d). As a result, the region R6 of the inner circumferential portion of the laminated core 1 is heated, but the other regions R1 to R5, R7, and R8 are not heated. Therefore, the circumferential and radial outward thermal expansion of the teeth 3 included in region R6 is absorbed by the other regions R1 to R5, R7, and R8. Furthermore, since region R6 is located on the opposite side of the central axis Ax from region R2, which was heated before the start of heating of region R6, region R6 is less susceptible to the influence of thermal expansion in region R2, even if heat remains in region R2.

[0031] The controller Ctr may switch the operation of the heating units 12A to 12H one by one at a predetermined interval (e.g., 0.5 to 50 seconds). Alternatively, the controller Ctr may switch the operation of the heating units 12A to 12H at least one by one at a predetermined interval (e.g., 0.5 to 50 seconds). Here, switching the operation of the heating units 12A to 12H at least one by one means operating at least one of the heating units 12A to 12H (e.g., heating units 12A to 12C) and then operating at least one of the heating units 12A to 12H that was not operated (e.g., heating units 12D and 12E), repeatedly, thereby operating all of the heating units 12A to 12H once while switching between them. For example, the controller Ctr may operate two heating units 12A and 12E and then operate one heating unit 12G. For example, the controller Ctr may operate the two heating sections 12A and 12E and then operate the two heating sections 12C and 12G.

[0032] The controller Ctr may control the heating units 12A to 12H so that the operation of each of the heating units 12A to 12H is repeated multiple times at different timings. That is, the operation of each of the heating units 12A to 12H at different timings constitutes one cycle, and the controller Ctr may be configured to execute the operation of the heating units 12A to 12H for X cycles (where X is a natural number equal to or greater than 1). For example, as illustrated in FIG. 7, after the initial (first cycle) operation of one of the heating units 12A to 12H, the second (second cycle) or subsequent operations of that heating unit may be performed. The number of repetitions (cycle number X) may be set according to the magnitude of strain remaining in the inner periphery of the laminated core 1. For example, when the size of the laminated core 1 is relatively large or when the shape of the inner periphery of the laminated core 1 is complex, the strain remaining in the inner periphery of the laminated core 1 tends to be large. Therefore, the number of repetitions (number of cycles X) may be set based on the size of the laminated core 1 and the shape of the inner periphery of the laminated core 1. The greater the number of repetitions (number of cycles X), the longer the cumulative time for heating the inner periphery of the laminated core 1, which tends to enable greater distortion removal.

[0033] The controller Ctr may be configured to intermittently heat (i.e., pulse heat) a region of the inner periphery of the laminated core 1 that faces the heating unit 12 by repeatedly turning the heating unit 12 on and off during operation of the heating unit 12. For example, as illustrated in FIGS. 3, 6, and 7, the controller Ctr may turn off the heating unit 12 when the temperature of region A (region R3 in the example of FIG. 3) that faces the heating unit 12 of the inner periphery of the laminated core 1 rises to a predetermined temperature (e.g., about 850°C). As illustrated in FIG. 7, the controller Ctr may turn on the heating unit 12 when the temperature of region A falls to a predetermined temperature (e.g., about 500°C). This allows the laminated core 1 to be heated within the annealing temperature range of 600°C to 900°C.

[0034] When the inner periphery of the laminated core 1 is intermittently heated by repeating on and off in this manner, the heat is mainly transferred to the vicinity of the surface of the laminated core 1 and is less likely to be transferred to the deeper parts of the laminated core. Specifically, as illustrated in Figures 3 and 6, regions B and C of the laminated core 1 where the joints 4 (crimps 4a and adhesive 4b) are present are less likely to be heated by the heat from the heating unit 12 (heating unit 12C in the example of Figure 3). As a result, it is possible to effectively heat the vicinity of the inner periphery of the laminated core 1, where distortion is likely to remain due to press working, and to reduce the impact on the joint state at the joints 4.

[0035] The time for which one heating section 12 is turned on may be about 0.01 to 30 seconds, about 0.01 to 20 seconds, or about 0.05 to 10 seconds. The time for which one heating section 12 is turned off may be about 0.01 to 30 seconds, about 0.01 to 20 seconds, or about 0.05 to 10 seconds. In this case, the vicinity of the surface of the inner periphery of the laminated core 1 can be heated more effectively by intermittent heating in which heating and cooling are repeated in a short period of time.

[0036] [Effect] According to the above example, the regions R1 to R8 of the inner periphery of the laminated core 1 are heated at different times by the heating units 12A to 12H. In other words, the inner periphery of the laminated core 1 has heated and unheated regions. Therefore, even if the heated regions undergo thermal expansion, the thermal expansion is absorbed by the unheated regions. In other words, the unheated regions provide an escape route for deformation due to thermal expansion in the inner periphery of the laminated core 1. Therefore, it is possible to suppress deformation of the inner periphery of the laminated core 1 when the laminated core 1 is heated.

[0037] According to the above example, the controller Ctr can operate one heating unit 12 and then operate another heating unit 12 that is not adjacent to the one heating unit 12. In this case, the influence of thermal expansion is less likely to occur between one region heated by one heating unit 12 and another region heated by another heating unit 12. Therefore, it is possible to further suppress deformation that occurs in the inner peripheral portion of the laminated core 1 when the laminated core 1 is heated.

[0038] According to the above example, the controller Ctr may operate one heating unit 12 and then operate another heating unit 12 that faces the first heating unit 12 across the central axis Ax. In this case, after one region is heated by one heating unit 12, another region that is as far away from the first region as possible is heated by the other heating unit 12. This makes it less likely that the effects of thermal expansion will occur between the first region and the other region. This makes it possible to further suppress deformation that occurs in the inner peripheral portion of the laminated core 1 when the laminated core 1 is heated.

[0039] According to the above example, the heating units 12A to 12H can be switched one by one at predetermined intervals (for example, 1 to 10 seconds). In this case, the inner peripheral portion of the laminated core 1 is heated by one heating unit 12 for a relatively short time, which makes it possible to prevent the inner peripheral portion of the laminated core 1 from being excessively heated.

[0040] According to the above example, the operation of the heating units 12A to 12H can be performed X cycles. In this case, the cumulative time for heating the inner periphery of the laminated core 1 increases in proportion to the number of repetitions. Therefore, by setting the number of repetitions according to the magnitude of the strain remaining in the inner periphery of the laminated core 1, it becomes possible to more effectively remove the remaining strain.

[0041] [Variations] The disclosure in this specification should be considered to be illustrative in all respects and not restrictive. Various omissions, substitutions, modifications, etc. may be made to the above examples without departing from the scope and spirit of the claims.

[0042] (1) With regard to the embodiment illustrated in FIG. 2, the number of heating portions 12 is not particularly limited as long as it is two or more, but may be the same number as the number of tooth portions 3 provided in the laminated core 1, or may be a divisor of the number of tooth portions 3 provided in the laminated core 1.

[0043] (2) The heating device 10 may include M (where M is a natural number equal to or greater than 1) heating sections 12. As illustrated in Fig. 8, the number of M heating sections 12 may be less than the number of regions R1 to R8 of the laminated core 1. In the example of Fig. 8, the heating device 10 includes two heating sections 12A and 12E.

[0044] The heating device 10 may further include a driving unit 20, as illustrated in Fig. 8. The driving unit 20 is configured to rotate the laminated core 1 around its central axis Ax (see arrow Ar in Fig. 8) based on a command signal from the controller Ctr. The driving unit 20 may include, for example, a mounting member on which the laminated core 1 is placed, and an actuator (e.g., a motor) that rotationally drives the mounting member.

[0045] 9, an example of the timing for heating the laminated core 1 when the laminated core 1 is heated using the heating device 10 according to the example of FIG. 8 will be described. First, the controller Ctr operates the heating units 12A and 12E as illustrated in FIG. 9(a). As a result, regions R1 and R5 of the inner circumferential portion of the laminated core 1 are heated, but the other regions R2 to R4 and R6 to R8 are not heated. Therefore, the thermal expansion of the teeth 3 included in regions R1 and R5 in the circumferential and radial outward directions is absorbed by the other regions R2 to R4 and R6 to R8.

[0046] After a predetermined time (e.g., 0.5 to 50 seconds) has elapsed since the heaters 12A and 12E started operating, the controller Ctr operates the drive unit 20 to rotate the laminated core 1 by approximately 90° around its central axis Ax, as illustrated in FIG. 9(b), and then operates the heaters 12A and 12E. As a result, regions R3 and R7 of the inner circumferential portion of the laminated core 1 are heated, but the other regions R1, R2, R4, R5, R6, and R8 are not heated. Therefore, the circumferential and radial outward thermal expansion of the teeth 3 included in regions R3 and R7 is absorbed by the other regions R1, R2, R4, R5, R6, and R8. Furthermore, since regions R3 and R7 are not adjacent to regions R1 and R5 in the circumferential direction of the laminated core 1, which were heated before heating of regions R3 and R7 began, regions R1 and R5 are less likely to be affected by thermal expansion in regions R1 and R5 even if heat remains in regions R1 and R5.

[0047] After a predetermined time (e.g., 0.5 to 50 seconds) has elapsed since the heaters 12A and 12E started operating, the controller Ctr operates the drive unit 20 to rotate the laminated core 1 by approximately 45° around its central axis Ax, as shown in Fig. 9(c), and then operates the heaters 12A and 12E. As a result, regions R4 and R8 of the inner circumferential portion of the laminated core 1 are heated, but the other regions R1 to R3 and R5 to R7 are not heated. Therefore, the thermal expansion of the teeth 3 included in regions R4 and R8 in the circumferential and radial outward directions is absorbed by the other regions R1 to R3 and R5 to R7.

[0048] After a predetermined time (e.g., 0.5 to 50 seconds) has elapsed since the heaters 12A and 12E started operating, the controller Ctr operates the drive unit 20 to rotate the laminated core 1 by approximately 90° around its central axis Ax, as illustrated in FIG. 9(d), and then operates the heaters 12A and 12E. As a result, regions R2 and R6 of the inner circumferential portion of the laminated core 1 are heated, but the other regions R1, R3, R4, R5, R7, and R8 are not heated. Therefore, the thermal expansion of the teeth 3 included in regions R2 and R6 in the circumferential and radial outward directions is absorbed by the other regions R1, R3, R4, R5, R7, and R8. Furthermore, since regions R2 and R6 are not adjacent to regions R4 and R8 in the circumferential direction of the laminated core 1, which were heated before heating of regions R2 and R6 began, regions R4 and R8 are less likely to be affected by thermal expansion in regions R4 and R8 even if heat remains in regions R4 and R8.

[0049] As described above, the drive unit 20 preferably rotates the laminated core 1 around its central axis Ax, but may also be configured to rotate M heating units 12 around the central axis Ax of the laminated core 1.

[0050] According to the embodiment illustrated in FIG. 8, first, M regions of the laminated core 1 are heated by M heating units 12. Then, as the laminated core 1 or the M heating units 12 rotate, a region of the laminated core 1 other than the M regions is heated by at least one of the M heating units 12. In other words, before and after the rotation, heated and unheated regions are generated in the laminated core 1. Therefore, even if the heated region thermally expands, the thermal expansion is absorbed by the unheated region. In other words, the unheated region provides an escape route for deformation due to thermal expansion in the laminated core 1. Therefore, it is possible to suppress deformation of the laminated core 1 when the laminated core 1 is heated.

[0051] 2 or 8, when the heating portions 12 are disposed in the central hole 1a of the laminated core 1, at least one heating portion 12 may be located in front of a tooth portion 3 or in front of a slot 5. Depending on the number of heating portions 12 and the number of teeth portions 3, one heating portion 12 may be located in front of two or more tooth portions 3 and one or more slots 5, or may be located in front of one or more tooth portions 3 and two or more slots 5.

[0052] (4) In the configuration illustrated in FIG. 2 or FIG. 8, the heating portion 12 may be disposed partially or entirely in the space inside the slot 5.

[0053] (5) With respect to the embodiment illustrated in Fig. 2 or 8, the heating device 10 may further include another heating unit disposed on the outer periphery of the laminated core 1. The controller Ctr may control the other heating unit to heat the outer periphery of the laminated core 1 with the other heating unit.

[0054] (6) In the embodiment illustrated in Fig. 2 or 8, a so-called outer stator laminated core is exemplified as the laminated core 1, in which multiple teeth 3 extend radially inward from the inner edge of the yoke portion 2. The technology according to the present disclosure is particularly preferable when applied to an outer stator laminated core, but may also be applied to other types of laminated cores 1.

[0055] For example, the laminated core 1 may be a so-called inner stator-type lamination core in which multiple teeth extend radially outward from the outer edge of the yoke. In this case, similar to the embodiment illustrated in FIG. 2, the N heating units 12 of the heating device 10 may be arranged to completely surround the outer periphery of the inner stator-type lamination core. That is, the inner diameter of the combined heating units 12A to 12H may be set larger than the outer diameter of the inner stator-type lamination core. Each of the N heating units 12 may face, for example, the tip of a tooth of the inner stator-type lamination core. That is, the number of N heating units 12 may be the same as the number of teeth of the inner stator-type lamination core. When heating the inner stator-type lamination core, the controller Ctr may operate the N heating units 12 at different times, similar to the outer stator-type lamination core described above. As a result, each tooth portion of the inner stator laminated stator core is heated individually at a different timing. Therefore, it is possible to suppress deformation of the laminated core 1 when heating the laminated core 1. When heating the inner stator laminated stator core, the controller Ctr may switch the operation of the N heating units 12 illustrated in Fig. 2 or 8 at least one by one at a predetermined interval (for example, 0.5 to 50 seconds).

[0056] Alternatively, similar to the embodiment illustrated in Fig. 8, the heating device 10 may include M heating units 12, which is fewer than the number of regions R1 to R8 of the laminated core 1, and the M heating units 12 may be arranged on the outer periphery of an inner stator-type laminated stator core. In this case, similar to the embodiment illustrated in Fig. 8, the laminated core 1 or the M heating units 12 may be rotated around the central axis Ax of the laminated core 1, thereby generating heated and unheated regions in the laminated core 1 before and after the rotation. This makes it possible to suppress deformation of the laminated core 1 when the laminated core 1 is heated.

[0057] For example, the laminated core 1 may be a split laminated core formed by combining multiple core pieces, or may be a non-split laminated core. One example of a non-split laminated core is one in which multiple teeth are provided on one yoke, and multiple folded punched members are stacked together so that the yoke is bent between the teeth to form an annular shape as a whole. Another example of a non-split laminated core is one in which multiple annular punched members are stacked together.

[0058] For example, the laminated core 1 may be a rotor laminated core. In this case, too, the number of heating portions 12 is not particularly limited as long as it is two or more.

[0059] [Other examples] Example 1. One example of a manufacturing method for a laminated core includes arranging N heating parts on the laminated core so that N heating parts are lined up circumferentially around the laminated core (where N is a natural number greater than or equal to 2), and heating N regions of the laminated core that the N heating parts face with the N heating parts. Heating with N heating parts includes switching the operation of the N heating parts one or more times but less than N times. In this case, the N regions of the laminated core are heated at different times by the N heating parts, one or more times but less than N times. In other words, the laminated core has heated regions and unheated regions. Therefore, even if the heated regions thermally expand, the thermal expansion is absorbed by the unheated regions. In other words, the unheated regions provide a means for deformation due to thermal expansion in the laminated core to escape. Therefore, it is possible to suppress deformation of the laminated core when the laminated core is heated.

[0060] Example 2: In the method of Example 1, when one of the N heating units heats one of the N regions corresponding to the heating unit, the one region may be intermittently heated by repeatedly turning on and off. In this case, the heat from the heating unit is mainly conducted near the surface of the laminated core and is less likely to be conducted to the deeper parts of the laminated core. Therefore, the vicinity of the surface (e.g., inner or outer peripheral surface) of the laminated core, where distortion is likely to remain due to press processing, is effectively heated. In addition, since the heat from the heating unit is less likely to be conducted to the joints (e.g., caulking, adhesive, etc.) that join the multiple punched members that make up the laminated core, it is possible to reduce the impact on the bonding condition at the joints.

[0061] Example 3: In the method of Example 2, when one of the N heating parts heats one of the N regions corresponding to the heating part, the one region may be intermittently heated by intermittently repeating an ON period of 0.01 to 30 seconds and an OFF period of 0.01 to 30 seconds. In this case, it is possible to heat the vicinity of the surface of the laminated core more effectively.

[0062] Example 4: In any of the methods of Examples 1 to 3, the N heating units may include four or more heating units, and heating with the N heating units may include operating one of the N heating units and then operating another of the N heating units that is not adjacent to the one heating unit. In this case, after one of the N regions of the laminated core is heated by one heating unit, another of the N regions that is not adjacent to the one heating unit is heated by the other heating unit. Therefore, the influence of thermal expansion between the one region and the other regions is less likely to occur. Therefore, it is possible to further suppress deformation of the laminated core when heating the laminated core.

[0063] Example 5: In the method of Example 4, heating with N heating units may include operating one of the N heating units and then operating another of the N heating units that faces the one heating unit across the central axis of the laminated core. In this case, after one of the N regions of the laminated core is heated by one heating unit, another region that is as far away from the one region as possible is heated. This makes it less likely that the effects of thermal expansion will occur between the one region and the other regions. This makes it possible to further suppress deformation of the laminated core when heating it.

[0064] Example 6: In any of the methods of Examples 1 to 5, heating with N heating units may include switching between the N heating units one by one at intervals of 0.5 to 50 seconds. In this case, heating of the laminated core by one heating unit is performed for a relatively short time, making it possible to prevent the laminated core from being overheated.

[0065] Example 7: In any of the methods of Examples 1 to 6, heating with N heating units may include repeatedly operating the N heating units at different times. In this case, the cumulative time for heating the laminated core increases in proportion to the number of repetitions. Therefore, by setting the number of repetitions according to the magnitude of the residual strain in the laminated core, it is possible to more effectively remove the residual strain.

[0066] Example 8: Another example of a manufacturing method for a laminated core includes arranging M (where M is a natural number greater than or equal to 1) heating portions so that they face the inner or outer periphery of the laminated core, heating M regions of the laminated core that the M heating portions face with the M heating portions, and rotating the laminated core or the M heating portions around the central axis of the laminated core to heat a region of the laminated core other than the M regions with at least one of the M heating portions. In this case, first, the M regions of the laminated core are heated by the M heating portions, and then, as the laminated core or the M heating portions rotate, a region of the laminated core other than the M regions is heated by at least one of the M heating portions. In other words, before and after the rotation, heated and unheated regions are generated in the laminated core. Therefore, even if the heated region thermally expands, that thermal expansion is absorbed by the unheated region. In other words, the unheated region provides a place for the laminated core to escape deformation due to thermal expansion. Therefore, it is possible to suppress deformation that occurs in the laminated core when the laminated core is heated.

[0067] Example 9: In the method of Example 8, when one of the M heating parts heats one region of the laminated core corresponding to that heating part, the one region may be intermittently heated by repeatedly turning on and off. In this case, the same effects as those of the method of Example 2 can be obtained.

[0068] Example 10: In the method of Example 9, when one of the M heating parts heats one region of the laminated core corresponding to that heating part, the one region may be intermittently heated by intermittently repeating an ON period of 0.01 to 30 seconds and an OFF period of 0.05 to 10 seconds. In this case, the same effects as those of the method of Example 3 can be obtained.

[0069] Example 11: In any of the methods of Examples 8 to 10, heating with M heating units or heating with at least one of the M heating units may include switching the M heating units one by one at intervals of 0.5 to 50 seconds. In this case, the same effects as those of the method of Example 6 can be obtained.

[0070] Example 12 In any of the methods of Examples 8 to 11, heating with M heating units or heating with at least one of the M heating units may include repeatedly operating the M heating units at different times multiple times.

[0071] Example 13: An example of a heating device includes N heating parts (where N is a natural number of 2 or more) and a control part. The control part is configured to execute a process of heating N regions of the laminated core that face the N heating parts by switching the operation of the N heating parts one by one but less than N, in a state where the N heating parts are arranged around the laminated core so as to be aligned in the circumferential direction of the laminated core. In this case, the same effects as those of the method of Example 1 can be obtained.

[0072] Example 14: Another example of a heating device includes M (where M is a natural number greater than or equal to 1) heating units, a drive unit configured to rotate the M heating units or laminated core around the central axis of the laminated core, and a control unit. The control unit is configured to perform the following operations in a state in which the M heating units are arranged to face the inner or outer periphery of the laminated core: operating the M heating units to heat M regions of the laminated core that the M heating units face; controlling the drive unit to rotate the laminated core or the M heating units around the central axis; and operating at least one of the M heating units to heat a region of the laminated core other than the M regions. In this case, the same effects as those of the method of Example 8 can be obtained. [Explanation of symbols]

[0073] 1... laminated core, 1a... center hole, 10... heating device, 12... heating section, 20... drive section, Ax... center axis, Ctr... controller (control section), R1 to R8... regions.

Claims

1. Arranging N heating portions (where N is a natural number of 2 or more) on the laminated core so that the N heating portions are aligned in the circumferential direction of the laminated core; heating N regions of the laminated core that face the N heating portions with the N heating portions; The method for manufacturing a laminated core includes switching the operation of the N heating sections by one or more but less than N heating sections at a time.

2. The method according to claim 1, wherein one of the N heating units intermittently turns on and off when heating one of the N regions corresponding to the one heating unit, thereby intermittently heating the one region.

3. 3. The method according to claim 2, wherein when one of the N heating units heats one of the N regions corresponding to the one heating unit, the one region is intermittently heated by intermittently repeating an on period of 0.01 seconds to 30 seconds and an off period of 0.01 seconds to 30 seconds.

4. The N heating units include four or more heating units, The method of claim 1, wherein heating using the N heating units includes operating one of the N heating units and then operating another of the N heating units that is not adjacent to the one heating unit.

5. 5. The method according to claim 4, wherein heating with the N heating units includes operating one of the N heating units and then operating another of the N heating units that faces the one heating unit across the central axis of the laminated iron core.

6. The method of claim 1 , wherein the heating with the N heating units includes switching the N heating units one by one at intervals of 0.5 seconds to 50 seconds.

7. The method according to any one of claims 1 to 6, wherein heating with the N heating units includes repeatedly operating the N heating units at different timings multiple times.

8. M (where M is a natural number equal to or greater than 1) heating portions are arranged so as to face the inner or outer periphery of the laminated core; heating M regions of the laminated core that face the M heating portions with the M heating portions; A method for manufacturing a laminated core, comprising: rotating the laminated core or the M heating parts around a central axis of the laminated core; and heating a region of the laminated core other than the M regions with at least one of the M heating parts.

9. N (where N is a natural number equal to or greater than 2) heating units; a control unit; The control unit is configured to perform a process of heating N regions of the laminated core that are faced by the N heating portions by switching the operation of the N heating portions one by one but less than N at a time, when the N heating portions are arranged on the laminated core so as to be aligned circumferentially.

10. M (where M is a natural number equal to or greater than 1) heating units; a driving unit configured to rotate the M heating units or laminated cores around a central axis of the laminated core; a control unit; The control unit a process of heating M regions of the laminated core that are faced by the M heating portions by operating the M heating portions in a state in which the M heating portions are arranged to face an inner circumferential portion or an outer circumferential portion of the laminated core; A process of controlling the driving unit to rotate the laminated core or the M heating units around the central axis; and a heating device configured to perform a process of heating a region of the laminated core that is different from the M regions by operating at least one of the M heating sections.

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