Manufacturing method for laminated iron cores

Abstract

To suppress dimensional defects caused by thermal deformation during the heat treatment process of a laminate of iron core pieces. [Solution] The method for manufacturing a laminated iron core includes a heat treatment step of heat-treating a laminate formed by stacking multiple iron core pieces. The heat treatment step is performed with a shielding member placed above or to the side of the laminate.

Description

Technical Field

[0001] The disclosed embodiments relate to a method for manufacturing a laminated core.

Background Art

[0002] The manufacturing process of a laminated core includes a heat treatment process. The heat treatment process is a general term for processes that change the properties of the workpiece by heating or cooling. The heat treatment processes included in the manufacturing process of a laminated core include, for example, quenching, annealing, tempering, stress relieving, oil firing, and blackening treatment (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] On the other hand, in the heat treatment process of the laminate of core pieces as the workpiece, if the convection in the furnace atmosphere is large, heat may be excessively supplied, causing deformations such as warping of the core pieces, and the laminate may have dimensional defects.

[0005] One aspect of the embodiment is made in view of the above, and an object is to provide a method for manufacturing a laminated core that can suppress dimensional defects due to thermal deformation in the heat treatment process of a laminate that becomes a laminated core.

Means for Solving the Problems

[0006] The method for manufacturing a laminated core according to one aspect of the embodiment includes a heat treatment step of heat-treating a laminate formed by laminating a plurality of core pieces. The heat treatment step is performed with a shielding member disposed above or on the side of the laminate.

Effects of the Invention

[0007] According to one embodiment, dimensional defects due to thermal deformation can be suppressed in the heat treatment process of a laminated body that forms a laminated core. The effects described herein are not necessarily limited, and any of the effects described in this disclosure may be used. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram showing an example of a manufacturing apparatus for laminated iron cores according to an embodiment. [Figure 2] Figure 2 is a side view showing an example of the configuration of a laminated group according to the embodiment. [Figure 3A] Figure 3A is a top view showing an example of the configuration of a conveying jig according to the embodiment. [Figure 3B] Figure 3B is a side view showing an example of the configuration of a conveying jig according to the embodiment. [Figure 4A] Figure 4A is a top view showing an example of the configuration of a plate according to the embodiment. [Figure 4B] Figure 4B is a side view showing an example of the configuration of a plate according to the embodiment. [Figure 5] Figure 5 is a plan view showing a configuration in which multiple plates are supported by a conveying jig. [Figure 6A] Figure 6A is a top view showing an example of the configuration of a cover mounting jig according to the embodiment. [Figure 6B] Figure 6B is a side view showing an example of the configuration of a cover mounting jig according to the embodiment. [Figure 7] Figure 7 is a top view showing an example of the cover configuration according to the embodiment. [Figure 8] Figure 8 is a plan view showing a state in which multiple covers are supported by a cover mounting jig in an embodiment. [Figure 9A] Figure 9A is an enlarged side view showing an example of the configuration of a laminated group according to the embodiment. [Figure 9B] Figure 9B is an enlarged side view showing an example of the configuration of a stacked structure in the reference example.

Mode for Carrying Out the Invention

[0009] Hereinafter, referring to the accompanying drawings, a method for manufacturing a laminated core disclosed in the present application will be described. Note that the present disclosure is not limited by the embodiments shown below.

[0010] Also, note that the drawings are schematic, and it is necessary to pay attention to the fact that the dimensional relationships of each element, the ratios of each element, etc. may be different from reality. Furthermore, there may be parts where the dimensional relationships and ratios between the drawings are different from each other.

[0011] <Manufacturing Apparatus> First, the configuration of a manufacturing apparatus 100 for a laminated core according to an embodiment will be described while referring to FIG. 1. FIG. 1 is a schematic diagram showing an example of a manufacturing apparatus 100 for a laminated core according to an embodiment.

[0012] The manufacturing apparatus 100 according to the embodiment is a continuous heat treatment apparatus that performs various heat treatment steps (also simply referred to as "heat treatment" in the present disclosure) on the laminate group 1 carried into the carrying-in part 110 and then discharges it to the discharging part 120. This laminate group 1 includes a plurality of laminates 13 (see FIG. 2).

[0013] The laminate 13, which is an object to be processed by the manufacturing apparatus 100, is formed by laminating a plurality of core pieces of electromagnetic steel sheets. The laminate 13 is formed by laminating a plurality of core pieces formed by punching a thin plate of electromagnetic steel sheet with a press in a separate process not shown. Note that each core piece may be joined by processing such as caulking or welding.

[0014] Then, the laminate 13 is subjected to various heat treatments and the like to be described later, and becomes a laminated core constituting the armature of a rotating electric machine. The detailed configuration of the laminate group 1 will be described later.

[0015] The manufacturing apparatus 100 includes a conveying device 130. Such a conveying device 130 conveys the laminate group 1 from the loading section 110 to the unloading section 120. The conveying device 130 has a driving sprocket wheel 131, a driven sprocket wheel 132, and a plurality of slats 133.

[0016] The driving sprocket wheel 131 is located at the unloading section 120 and is driven by a rotary electric motor (not shown). The driven sprocket wheel 132 is located at the loading section 110.

[0017] Also, an endless chain (not shown) is wound between the driving sprocket wheel 131 and the driven sprocket wheel 132. And a plurality of slats 133 are attached side by side to this endless chain. The plurality of slats 133 are arranged along the moving direction of the endless chain.

[0018] In the manufacturing apparatus 100, between the loading section 110 and the unloading section 120, in order from the loading section 110 side, a degreasing furnace 140, an annealing furnace 150, a first cooling section 160, a bluing furnace 170, and a second cooling section 180 are arranged side by side. Also, shutters 191 to 196 are located between the loading section 110 and the unloading section 120.

[0019] The degreasing furnace 140 is a heat treatment furnace that evaporates the oil adhered to the core pieces constituting the laminate 13 in the punching process, that is, a heat treatment furnace that performs so-called "oil baking" on the plurality of laminates 13.

[0020] The degreasing furnace 140 has a heater 141 and discharge cylinders 142 and 143. The heater 141 is located, for example, on the upper surface in the internal space of the degreasing furnace 140 and raises the temperature of the plurality of laminates 13 to the degreasing temperature (for example, about 300 to 400°C). The discharge cylinders 142 and 143 are located on the upstream side and the downstream side of the degreasing furnace 140, respectively.

[0021] In the oil de-oil furnace 140, the oil heated and evaporated by the heater 141 is discharged to the outside through the discharge pipes 142 and 143. The oil de-oil furnace 140 is located adjacent to, for example, the loading section 110. A shutter 191 is located between the loading section 110 and the oil de-oil furnace 140.

[0022] The annealing furnace 150 is a heat treatment furnace that performs "annealing," which involves heating and annealing multiple laminates 13. The annealing furnace 150 has a heater 151. The heater 151 is located, for example, on the upper surface of the internal space of the annealing furnace 150 and raises the temperature of the multiple laminates 13 to the annealing temperature (for example, about 800°C).

[0023] The annealing furnace 150 is located, for example, downstream of the de-oil furnace 140. A shutter 192 is located between the de-oil furnace 140 and the annealing furnace 150.

[0024] The first cooling section 160 is a section for cooling the multiple laminates 13 that have undergone annealing treatment to a temperature suitable for starting the bluing process described later. The first cooling section 160 has an intake pipe 161 and an exhaust pipe 162.

[0025] The intake pipe 161 takes in cooling air from the outside. The exhaust pipe 162 discharges the cooling air, which has been heated by absorbing heat from the multiple stacked structures 13, to the outside. The first cooling section 160 is located, for example, downstream of the annealing furnace 150. A shutter 193 is located between the annealing furnace 150 and the first cooling section 160.

[0026] The bluing furnace 170 is a heat treatment furnace that generates a film of triiron tetroxide (Fe3O4) on the surface of multiple laminates 13, that is, a heat treatment furnace that performs what is known as "bluing" on multiple laminates 13.

[0027] The bluing furnace 170 includes a heater 171 and a gas supply nozzle 172. The heater 171 is located, for example, at the top of the internal space of the bluing furnace 170 and cools the atmosphere inside the bluing furnace 170 in a time-temperature curve suitable for coating formation.

[0028] The gas supply nozzle 172 blows in an inert gas (e.g., nitrogen gas) and water vapor into the brewing furnace 170. The brewing furnace 170 is located, for example, downstream of the first cooling section 160. A shutter 194 is located between the first cooling section 160 and the brewing furnace 170.

[0029] The second cooling section 180 is a compartment for cooling the multiple laminates 13, after the bluing process has been completed, to room temperature. The second cooling section 180 has an intake pipe 181 and an exhaust pipe 182.

[0030] The intake pipe 181 takes in cooling air from the outside. The exhaust pipe 182 discharges the cooling air, which has been heated by absorbing heat from the multiple stacked structures 13, to the outside. The second cooling section 180 is located, for example, downstream of the brewing furnace 170 and upstream of the discharge section 120.

[0031] A shutter 195 is located between the brewing furnace 170 and the second cooling section 180. Additionally, a shutter 196 is located between the second cooling section 180 and the discharge section 120.

[0032] Shutters 191-196 are devices that prevent the atmosphere inside each compartment (oil de-oil furnace 140-second cooling section 180) from flowing into other compartments and out to the outside. Each shutter 191-196 has a shielding plate and an actuator (not shown) (e.g., an air cylinder) for raising and lowering such shielding plate.

[0033] In Figure 1, the shutter 191 located at the entrance of the oil de-oil furnace 140 is shown with the shielding plate raised, i.e., the entrance to the oil de-oil furnace 140 is open. The other shutters 192 to 196 are shown with the shielding plates lowered, i.e., the boundaries of each compartment are closed.

[0034] The manufacturing apparatus 100 is controlled by a control device 200, which includes a computer (not shown). The control device 200 controls the transport apparatus 130 by executing a program stored in the computer.

[0035] For example, the control device 200 executes such a program to open and close shutters 191 to 196, operate the de-oiling furnace 140, the annealing furnace 150, and the bluing furnace 170, and adjust the flow rate of cooling air supplied to the first cooling unit 160 and the second cooling unit 180.

[0036] The manufacturing apparatus 100 is operated in the following sequence, for example: First, an operator, for example, using a hoist (not shown), or a robot, loads the stacked material group 1 into the loading section 110.

[0037] Once the loading of the stacked material 1 is complete, the worker turns on a start switch (not shown). When the start switch is turned on, the control device 200 commands the shutter 191 located at the entrance of the oil de-oil furnace 140 to open the entrance of the oil de-oil furnace 140.

[0038] The control device 200 then commands the transport device 130 to transfer the stacked body group 1, on which the multiple stacked bodies 13 are placed, into the oil de-oil furnace 140.

[0039] Subsequently, the control device 200 commands the shutter 191 to close the entrance to the oil removal furnace 140, and commands the oil removal furnace 140 to operate the heater 141 to remove the oil adhering to the laminate 13 placed on the laminate group 1. In other words, the laminate 13 is subjected to "oil burning".

[0040] Once the "oil quenching" is complete, the control device 200 commands the shutter 192 and the transport device 130, which are located at the boundary between the de-oil furnace 140 and the annealing furnace 150, to transport the stacked body group 1, on which the multiple stacked bodies 13 are placed, into the annealing furnace 150.

[0041] Then, the shutter 192 is commanded to close the entrance to the annealing furnace 150, and the annealing furnace 150 is commanded to operate the heater 151, thereby performing "annealing" on the laminate 13.

[0042] Thereafter, in the same manner, after processing in each section is completed, the stacked body group 1 on which the multiple stacked bodies 13 are placed is moved to the next section and the next processing is performed. Once all processing is complete, the stacked body group 1 on which the multiple stacked bodies 13 are placed is moved to the discharge section 120.

[0043] In this disclosure, the manufacturing apparatus 100 for performing heat treatment on the laminate group 1 is not limited to the example in Figure 1, and the laminate group 1 may be heat-treated using various manufacturing apparatuses different from the configuration in Figure 1.

[0044] <Laminated structures> Next, the detailed configuration of the laminate group 1, which is subjected to heat treatment by the manufacturing apparatus 100 according to the embodiment, will be described with reference to Figures 2 to 9B. Figure 2 is a side view showing an example of the configuration of the laminate group 1 according to the embodiment. In this disclosure, hatching may be applied to each component in the side views, including Figure 2, for ease of understanding.

[0045] As shown in Figure 2, the laminated group 1 according to this embodiment has a lower section 2, a plurality (six in Figure 2) of middle sections 3, and an upper section 4. The laminated group 1 according to this embodiment is constructed by stacking the plurality of middle sections 3 in multiple layers on top of the lower section 2, and then stacking the upper section 4 on top of that.

[0046] The lower section 2 is a frame that holds multiple middle sections 3 stacked in multiple layers. Each middle section 3 has a transport jig 11, multiple plates 12, and multiple stacked bodies 13. The transport jig 11 supports the multiple plates 12 together. The plates 12 are plate-shaped and support the stacked bodies 13 in the middle section 3.

[0047] As shown in Figure 2, in the middle section 3, multiple plates 12 are supported on the conveying jig 11. In addition, multiple laminates 13 are supported on each of the multiple plates 12. Furthermore, in the middle section 3, the multiple laminates 13 are positioned almost flush with each other.

[0048] Furthermore, in the laminated body group 1 according to this embodiment, since the middle section 3 is stacked in multiple layers, the laminated body 13 is also stacked in multiple layers. The detailed configuration of the transport jig 11 and the plate 12 will be described later.

[0049] The upper section 4 includes a cover mounting jig 21 and a plurality of covers 22. The cover mounting jig 21 supports the plurality of covers 22 together. The cover 22 is an example of a shielding member, and is, for example, plate-shaped. The detailed configuration of the cover mounting jig 21 and the covers 22 will be described later.

[0050] Figure 3A is a top view showing an example of the configuration of the conveying jig 11 according to the embodiment. Figure 3B is a side view showing an example of the configuration of the conveying jig 11 according to the embodiment. The conveying jig 11 is made of, for example, heat-resistant cast steel.

[0051] As shown in Figure 3A, the transport jig 11 has an outer frame 11a that forms the outline in plan view, and a plurality of diagonal bars 11b supported at both ends by the outer frame 11a. The plurality of diagonal bars 11b intersect with each other, forming a diamond-shaped grid as a whole.

[0052] Multiple support tubes 11c are located at each of the multiple intersections of the diagonal bars 11b (13 in the figure). As shown in Figure 3B, the support tubes 11c protrude upward from the outer frame 11a in a side view. The height of the support tubes 11c is greater than the sum of the thickness of the plate 12 (see Figure 2) and the thickness of the laminate 13 (see Figure 2).

[0053] Annular battens 11d are arranged concentrically around the support cylinder 11c. All diagonal battens 11b and all annular battens 11d are arranged so that their upper surfaces are substantially flush. That is, all diagonal battens 11b and all annular battens 11d are configured to form a single plane on their upper surfaces.

[0054] Figure 4A is a top view showing an example of the configuration of the plate 12 according to the embodiment. Figure 4B is a side view showing an example of the configuration of the plate 12 according to the embodiment. The plate 12 is constructed by cutting from, for example, a stainless steel plate with a thickness of about 5 mm.

[0055] As shown in Figure 4A, the plate 12 is a disc having a predetermined diameter, and a central hole 12a of a predetermined diameter is provided at the center of the disc. The inner diameter of the central hole 12a is slightly larger than the outer diameter of the support cylinder 11c (see Figure 3A) of the conveying jig 11 (see Figure 3A). A number of (four in the figure) fan-shaped through holes 12b are provided around the central hole 12a.

[0056] The multiple through holes 12b are arranged, for example, at equal intervals along the circumferential direction. In addition, as shown in Figures 4A and 4B, multiple (three in the figures) pins 12c are provided on the upper and lower surfaces of the plate 12, respectively.

[0057] The multiple through-holes 12b provided in the plate 12 function as ventilation holes that promote atmospheric convection during the heat treatment process by the manufacturing apparatus 100 (see Figure 1). Furthermore, when the plate 12 is placed on an item other than the transport jig 11, or when multiple plates 12 are stacked and temporarily placed, the pins 12c also function as spacers that separate the plate 12 from other items or other plates 12.

[0058] As described above, since the plate 12 is equipped with pins 12c, when the plate 12 is placed on top of other items or when multiple plates 12 are stacked and temporarily stored, the surface of the plate 12 does not come into contact with other items. Therefore, scratches and dirt are less likely to adhere to the surface of the plate 12. Consequently, damage and soiling of the plate 12 are suppressed.

[0059] In Figures 4A and 4B, the contour of the laminate 13 placed on the plate 12 is shown by a dashed line. As is clear from this, the laminate 13 is in overall surface contact with the plate 12 on its underside. That is, the plate 12 has a shape and dimensions such that the laminate 13 is in overall surface contact with the plate 12 on its underside.

[0060] As shown in Figure 4A, the outer diameter of the plate 12 is larger than the outer diameter of the laminate 13, and the inner diameter of the plate 12 is smaller than the inner diameter of the laminate 13.

[0061] Furthermore, the multiple pins 12c provided on the upper surface of the plate 12 are arranged adjacent to the outer contour of the laminate 13 with a small gap in between. This allows the laminate 13 to be easily positioned relative to the plate 12.

[0062] Although Figures 4A and 4B show examples in which the plate 12 is provided with multiple pins 12c, this disclosure is not limited to such examples, and the plate 12 may not be provided with pins 12c.

[0063] Figure 5 is a plan view showing a configuration in which multiple plates 12 are supported by the conveying jig 11. As shown in Figure 5, the plates 12 are supported by the conveying jig 11 by fitting their central holes 12a (see Figure 4A) into the support cylinders 11c (see Figure 3A).

[0064] Furthermore, since all the diagonal bars 11b (see Figure 3A) and all the annular bars 11d (see Figure 3A) are configured to form a single plane on their upper surfaces, the plate 12 is supported in contact with the diagonal bars 11b and annular bars 11d. As a result, the plate 12 is stably supported by the conveying jig 11.

[0065] As shown in Figure 2, when one intermediate section 3 is stacked on top of another intermediate section 3, the transport jig 11 of the upper intermediate section 3 is placed on the upper surface of the support cylinder 11c of the lower intermediate section 3.

[0066] Furthermore, since the height of the support cylinder 11c is greater than the sum of the thickness of the plate 12 and the thickness of the laminate 13, a gap is formed between the laminate 13 of the lower middle section 3 and the transport jig 11 of the upper middle section 3.

[0067] Figure 6A is a top view showing an example of the configuration of the cover mounting jig 21 according to the embodiment. Figure 6B is a side view showing an example of the configuration of the cover mounting jig 21 according to the embodiment. The cover mounting jig 21 is made of, for example, heat-resistant cast steel.

[0068] As shown in Figure 6A, the cover mounting jig 21 has an outer frame 21a that forms the contour in plan view, and a plurality of diagonal bars 21b supported at both ends by the outer frame 21a. The plurality of diagonal bars 21b intersect with each other, forming a rhombus-shaped grid as a whole.

[0069] Multiple support tubes 21c are located at each of the multiple intersections of the diagonal bars 21b (13 in the figure). As shown in Figure 6B, the support tubes 21c protrude slightly upward from the outer frame 21a in a side view. The height of the support tubes 21c is approximately equal to the thickness of, for example, the cover 22 (see Figure 2).

[0070] Annular battens 21d are arranged concentrically around the support cylinder 21c. All diagonal battens 21b and all annular battens 21d are arranged so that their upper surfaces are substantially flush. That is, all diagonal battens 21b and all annular battens 21d are configured to form a single plane on their upper surfaces.

[0071] Figure 7 is a top view showing an example of the configuration of the cover 22 according to the embodiment. The cover 22 is constructed, for example, by cutting it from a stainless steel plate with a thickness of about 5 mm.

[0072] As shown in Figure 7, the cover 22 is a disc having a predetermined diameter, with a central hole 22a of a predetermined diameter at the center of the disc. The inner diameter of the central hole 22a is slightly larger than the outer diameter of the support cylinder 21c (see Figure 6A) of the cover mounting jig 21 (see Figure 6A). A number of (four in the figure) fan-shaped through holes 22b are provided around the central hole 22a.

[0073] The multiple through-holes 22b are arranged, for example, at equal intervals along the circumferential direction. The multiple through-holes 22b provided in the cover 22 function as ventilation holes that promote atmospheric convection during the heat treatment process by the manufacturing apparatus 100 (see Figure 1).

[0074] In Figure 7, the contour of the laminate 13 located below the cover 22 is shown by a dashed line. As is clear from this, the entire upper surface of the laminate 13 is covered by the cover 22. That is, the cover 22 has a shape and dimensions such that the entire upper surface of the laminate 13 is covered.

[0075] As shown in Figure 7, the outer diameter of the cover 22 is larger than the outer diameter of the laminate 13, and the inner diameter of the cover 22 is smaller than the inner diameter of the laminate 13.

[0076] Figure 8 is a plan view showing a state in which multiple covers 22 are supported by the cover mounting jig 21 in an embodiment. As shown in Figure 8, the cover 22 is supported by the cover mounting jig 21 by fitting its central hole 22a (see Figure 7) into the support cylinder 21c (see Figure 6A).

[0077] Furthermore, since all the diagonal bars 21b and all the annular bars 21d are configured to form a single plane on their upper surfaces, the cover 22 is supported in contact with the diagonal bars 21b and the annular bars 21d. As a result, the cover 22 is stably supported by the cover mounting jig 21.

[0078] As shown in Figure 2, when the upper section 4 is stacked on top of the middle section 3 of the uppermost section, the cover mounting jig 21 of the upper section 4 is placed on the upper surface of the support cylinder 11c of the middle section 3 of the uppermost section.

[0079] Furthermore, since the height of the support cylinder 11c is greater than the sum of the thickness of the plate 12 and the thickness of the laminate 13, a gap is formed between the laminate 13 of the uppermost middle section 3 and the cover mounting jig 21 of the upper section 4.

[0080] Figure 9A is an enlarged side view showing an example of the configuration of the laminate group 1 according to the embodiment, and is an enlarged side view of part A shown in Figure 2. Figure 9B is an enlarged side view showing an example of the configuration of the laminate group 1A of the reference example, and is a figure corresponding to Figure 9A of the embodiment.

[0081] As shown in Figure 9A, in this embodiment, the heat treatment process for the multiple laminates 13 described above is preferably carried out with the cover 22 positioned above the uppermost laminate 13A among the multiple laminates 13.

[0082] As shown in Figure 9B, when the cover 22 is not placed above the top layer 13A, there is nothing particularly obstructing the airflow around the top surface 13A1 of this layer 13A, resulting in large atmospheric convection. On the other hand, in the layers 13B other than the top layer, the plate 12 is placed directly above, so the surrounding airflow is relatively small.

[0083] In the heat treatment process of the laminate group 1A in this state, if an attempt is made to supply sufficient heat to the laminates 13B other than the top layer, where the convection of the surrounding atmosphere is small, there is a risk that the top layer laminate 13A, where the convection of the surrounding atmosphere is large, will receive an excessive amount of heat.

[0084] Therefore, in the example laminate group 1A, this excessive heat supply sometimes caused deformation such as warping of the iron core piece in the uppermost layer of the laminate 13A, resulting in defects such as dimensional defects in the laminate 13A.

[0085] On the other hand, in the laminate group 1 according to this embodiment, as shown in Figure 9A, the cover 22 is positioned above the uppermost laminate 13A, so that atmospheric convection can be made relatively small even around the uppermost laminate 13A.

[0086] This makes it possible to bring the heat supply to the uppermost layer 13A in the heat treatment process of the laminate group 1 closer to the heat supply to the other layers 13B. Therefore, according to this embodiment, dimensional defects due to thermal deformation can be suppressed in the heat treatment process of the laminate 13 which forms the laminated core.

[0087] In the embodiments described so far, an example has been shown in which the cover 22 is placed above the uppermost layer 13A of the multi-layered laminate 13, but this disclosure is not limited to such an example.

[0088] For example, in a configuration where multiple laminates 13 are not stacked in multiple layers, such as a laminate group 1 having one middle section 3, the cover 22 may be placed above the laminate 13.

[0089] Of the multiple iron core pieces stacked within the laminate 13, the uppermost iron core piece has a larger exposed area than the other iron core pieces. Therefore, if sufficient heat is supplied to the other iron core pieces with smaller exposed areas, there is a risk that the uppermost iron core piece with a larger exposed area will receive excessive heat. This phenomenon is particularly pronounced when there is significant convection in the surrounding atmosphere around the uppermost iron core piece.

[0090] Therefore, even in the heat treatment process of a laminated body 13 that is not stacked in multiple layers, by positioning the cover 22 above the laminated body 13, the heat supply to the top layer of iron core pieces can be made to be closer to the heat supply to the iron core pieces other than the top layer.

[0091] Therefore, according to this embodiment, dimensional defects due to thermal deformation can be suppressed in the heat treatment process of the laminated body 13 which forms the laminated core.

[0092] Furthermore, in the embodiment, as shown in Figure 1, the heater may be placed on the upper surface of the internal space in various heat treatment furnaces. In this case, in the laminate group 1A of the reference example shown in Figure 9B, radiant heat from the heater is directly applied to the uppermost laminate 13A during the heat treatment process.

[0093] Therefore, in the example laminate group 1A, excessive heat was supplied to the uppermost laminate 13A, making the iron core pieces in the uppermost layer more susceptible to deformation such as warping.

[0094] On the other hand, in this embodiment, even when the heater is located on the upper surface of the internal space in the heat treatment furnace, the cover 22 is positioned above the uppermost layer 13A, which suppresses the direct application of radiant heat from the heater to the uppermost layer 13A.

[0095] Therefore, according to this embodiment, dimensional defects due to thermal deformation can be suppressed in the heat treatment process of the laminated body 13 which forms the laminated core.

[0096] In this disclosure, if the heater is located on the side of the internal space in a heat treatment furnace, a shielding member such as a cover or shutter may be placed on the side of the laminate group 1 facing the heater. This makes it possible to suppress the direct application of radiant heat from the heater to the laminate 13 that is directly facing the heater.

[0097] Therefore, according to this embodiment, dimensional defects due to thermal deformation can be suppressed in the heat treatment process of the laminated body 13 which forms the laminated core.

[0098] Furthermore, in this disclosure, when a heater is located on the upper surface of the internal space in a heat treatment furnace, the shielding member located above the uppermost layer 13A is not limited to a cover 22, and a shutter may be located between the layer group 1 and the heater.

[0099] This also prevents direct radiant heat from the heater from being applied to the uppermost layer 13A, thereby suppressing dimensional defects due to thermal deformation during the heat treatment process of the layer 13 which forms the laminated core.

[0100] Furthermore, in the embodiment, as shown in Figure 9A, a predetermined first distance D1 (for example, about 1 cm) may be provided between the upper surface 13A1 of the uppermost laminate 13A and the lower surface 22d of the cover 22. In other words, in the embodiment, the uppermost laminate 13A and the cover 22 do not need to be in contact with each other.

[0101] As a result, the cover 22 is placed on top of the uppermost layer 13A, which suppresses deformation of the uppermost layer 13A. Therefore, according to this embodiment, dimensional defects of the uppermost layer 13A can be suppressed.

[0102] In addition, in this embodiment, a predetermined second distance D2 (for example, about 1 cm) may be provided between the upper surface 13B1 of the laminated layers 13B other than the top layer and the lower surface 12d of the plate 12 located directly above the laminated layer 13B. In other words, in this embodiment, the laminated layers 13B other than the top layer and the plate 12 located directly above the laminated layer 13B do not need to be in contact with each other.

[0103] As a result, the plate 12 is placed on top of the laminated layers 13B other than the top layer, which suppresses deformation of the laminated layers 13B. Therefore, according to this embodiment, dimensional defects of the laminated layers 13B other than the top layer can be suppressed.

[0104] In addition, in this embodiment, the first distance D1 between the upper surface 13A1 of the uppermost laminate 13A and the lower surface 22d of the cover 22 may be equal to the second distance D2 between the upper surface 13B1 of the other laminates 13B and the lower surface 12d of the plate 12 located directly above the laminate 13B.

[0105] This makes it possible to equalize the heat supply to the uppermost layer 13A and the heat supply to the other layers 13B during the heat treatment process of the laminate group 1. Therefore, according to this embodiment, dimensional defects due to thermal deformation can be further suppressed during the heat treatment process of the laminate 13 which forms the laminated core.

[0106] Furthermore, in the embodiment, as shown in Figures 7 and 4A, the cover 22 and the plate 12 may have the same planar shape. For example, the cover 22 and the plate 12 may each have a plurality of through holes 22b and a plurality of through holes 12b, respectively, with the same planar shape.

[0107] This makes it possible to further equalize the convection around the uppermost layer 13A and the convection around the other layers 13B. Therefore, in the heat treatment process of the layer group 1, it is possible to further equalize the heat supply to the uppermost layer 13A and the heat supply to the other layers 13B.

[0108] Therefore, according to this embodiment, dimensional defects due to thermal deformation can be further suppressed in the heat treatment process of the laminated body 13 which forms the laminated core.

[0109] Furthermore, in this embodiment, as shown in Figures 6A and 3A, the cover mounting jig 21 and the transport jig 11 may have the same planar shape. This allows the transport parameters of the upper section 4, which is transported by gripping the cover mounting jig 21, to be brought closer to the transport parameters of the middle section 3, which is transported by gripping the transport jig 11, in the pre-process of forming the stacked body group 1 with a robot or the like.

[0110] Therefore, according to this embodiment, the laminate group 1 can be easily formed in the pretreatment.

[0111] In this embodiment, the multiple laminates 13 included in the laminate group 1 may all be of the same type, or it may include two or more types of laminates 13.

[0112] Furthermore, in the embodiment, when the middle section 3 is stacked in multiple layers, the structure may be designed to prevent misalignment or rotational misalignment between the stacked transport jigs 11. For example, a projection or step may be provided at the tip of at least one support cylinder 11c, and grooves, holes, or steps may be provided on the back side of the support cylinder 11c in the transport jig 11, and these may be fitted together when the transport jigs 11 are stacked. The same configuration may also be used for the transport jig 11 of the middle section 3 and the cover mounting jig 21 of the upper section 4, so as to prevent misalignment or rotational misalignment between them as well.

[0113] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications are possible without departing from the spirit of the invention.

[0114] Further effects and modifications can be readily derived by those skilled in the art. Therefore, broader aspects of the present invention are not limited to the specific details and representative embodiments expressed and described above. Accordingly, various modifications are possible without departing from the spirit or scope of the overall concept of the invention as defined by the appended claims and their equivalents.

[0115] Furthermore, this technology can also be configured as follows. (1) This includes a heat treatment step of heat-treating a laminate composed of multiple iron core pieces stacked together, The heat treatment process is carried out with a shielding member placed above or to the side of the laminate. A method for manufacturing laminated iron cores. (2) The heat treatment process is carried out with the shielding member positioned above the laminate. The method for manufacturing a laminated iron core as described in (1) above. (3) The heat treatment process is carried out by stacking multiple laminates in multiple stages. The shielding member is positioned above the uppermost layer of the laminate. The method for manufacturing a laminated iron core as described in (2) above. (4) A predetermined first distance is provided between the upper surface of the uppermost layer of the laminate and the lower surface of the shielding member. The method for manufacturing a laminated iron core as described in (3) above. (5) In the heat treatment process, the multiple laminates are each placed on multiple plate-shaped plates, A second distance equal to the first distance is provided between the upper surface of the laminate, excluding the uppermost layer, and the lower surface of the plate located directly above the laminate. The method for manufacturing a laminated iron core as described in (4) above. (6) The shielding member and the plate have the same planar shape. The method for manufacturing a laminated iron core as described in (5) above. (7) The process further includes, before the heat treatment step, a transfer step of transferring the laminate into the heat treatment furnace. A method for manufacturing a laminated iron core as described in any one of (1) to (6) above. [Explanation of Symbols]

[0116] 1. Stacked structure group 12 plates 12d bottom surface 13, 13A, 13B laminate 13A1, 13B1 top surface 22 Cover (an example of a shielding member) 22d Bottom surface 140 Oil removal furnace (an example of a heat treatment furnace) 150 Annealing furnace (an example of a heat treatment furnace) 170. Blueing furnace (an example of a heat treatment furnace) D1 1st distance D2 2nd distance

Claims

1. This includes a heat treatment step of heat-treating a laminate composed of multiple iron core pieces stacked together, The heat treatment process is carried out with a shielding member placed above or to the side of the laminate. A method for manufacturing laminated iron cores.

2. The heat treatment process is carried out with the shielding member positioned above the laminate. A method for manufacturing a laminated iron core according to claim 1.

3. The heat treatment process is carried out by stacking multiple laminates in multiple stages. The shielding member is positioned above the uppermost layer of the laminate. The method for manufacturing a laminated iron core according to claim 2.

4. A predetermined first distance is provided between the upper surface of the uppermost layer of the laminate and the lower surface of the shielding member. The method for manufacturing a laminated iron core according to claim 3.

5. In the heat treatment process, the multiple laminates are each placed on multiple plate-shaped plates, A second distance equal to the first distance is provided between the upper surface of the laminate, excluding the top layer, and the lower surface of the plate located directly above the laminate. The method for manufacturing a laminated iron core according to claim 4.

6. The shielding member and the plate have the same planar shape. The method for manufacturing a laminated iron core according to claim 5.

7. The process further includes, before the heat treatment step, a transfer step of transferring the laminate into the heat treatment furnace. A method for manufacturing a laminated iron core according to any one of claims 1 to 6.

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