Laminated iron core and laminated iron core manufacturing method

Abstract

Intermediate iron core pieces 17 and 18 disposed between block iron cores 11 and 12 are provided with second resin passages 17b and 18b. A prescribed magnet insertion hole 15 in a laminated iron core 10 obtained by laminating the block iron cores 11 and 12 communicates, via the second resin passages 17b and 18b, with another magnet insertion hole 16 positioned to be out of alignment with the magnet insertion hole 15. As a result, in the process of filling the magnet insertion holes 15 and 16 with resin, the resin is caused to reach both of the magnet insertion holes 15 and 16, so that it is possible, in each of the magnet insertion holes 15 and 16, to fix a permanent magnet by having the resin present around the permanent magnet.

Description

Laminated Core and Method for Manufacturing the Same

[0001] The present disclosure relates to a laminated core forming a core in a rotor of a rotating electric machine.

[0002] In a stator or rotor of a rotating electric machine such as an electric motor or a generator, a laminated core is generally used as a core in which coils or permanent magnets are disposed. In disposing coils or permanent magnets on such a core of a laminated core, various devices have been conventionally made.

[0003] For example, in the case of the core of a rotor, particularly in the case of the rotor core of an IPM motor, a structure in which a permanent magnet is inserted and fixed in a magnet insertion hole of a laminated core has been adopted. The permanent magnet is inserted into the magnet insertion hole and fixed by adhesion with an adhesive or filling with a filler or the like.

[0004] In such a rotor of an IPM motor, in order to prevent the output torque from rippling due to cogging torque and leading to the generation of noise and vibration, it is widely practiced to make the rotor have a skew structure. For example, a structure is known in which a laminated core forming a rotor is divided into a plurality of parts in the lamination direction together with the fixed permanent magnets, and the positions of the permanent magnets in each divided core are shifted by a predetermined angle around the central axis and combined. As an example of such a conventional rotor in a rotating electric machine, there is one disclosed in Japanese Patent Application Laid-Open No. 2004-248,442.

[0005] Japanese Patent Application Laid-Open No. 2004-248,442

[0006] As shown in the above-mentioned Patent Document 1, a conventional rotor has a structure in which a predetermined number of rotor modules each composed of a core formed by laminating a predetermined number of core plates and a permanent magnet supported thereby are laminated. The rotor modules are positioned by being shifted in the circumferential direction by a predetermined pitch angle with respect to adjacent other rotor modules, so that the rotor can be equivalently skewed by being divided into three equal parts in its axial direction. In each rotor module, magnet insertion holes are formed so as to communicate axially in the laminated core plates, and permanent magnets are inserted into the respective magnet insertion holes and fixed by adhesion or the like.

[0007] In order to create a skewed rotor structure, it is necessary to stack rotor modules with the positions of the magnet insertion holes offset by a predetermined angle in the circumferential direction. However, this may result in the magnet insertion holes not being continuous in the axial direction between rotor modules. Ideally, the adhesive or filler used to fix the permanent magnets in the magnet insertion holes should be supplied to the magnet insertion holes all at once after the rotor modules have been stacked, in order to minimize the process. However, if the magnet insertion holes of each rotor module are not continuous, even if adhesive or the like is supplied to the magnet insertion holes of the stacked rotor modules from the outside, it becomes difficult for the adhesive or the like to flow from these magnet insertion holes to the magnet insertion holes of other rotor modules that are not continuous in the axial direction. As a result, the supplied adhesive or the like may not be able to sufficiently flow to the target position in each magnet insertion hole of the stacked rotor modules, and there is a risk that the permanent magnets in the magnet insertion holes will not be properly fixed.

[0008] Therefore, in the case of a skewed structure, a method was generally adopted in which permanent magnets were inserted into magnet insertion holes for each rotor module, the permanent magnets were fixed by adhesive or other means, and then the rotor modules were stacked and integrated. However, this method had the problem of increasing manufacturing costs because the process of fixing the permanent magnets was required for each stage of the rotor module, making the manufacturing process complicated.

[0009] This disclosure was made to solve the aforementioned problems, and aims to provide a laminated core and a method for manufacturing a laminated core, in which intermediate core pieces are arranged between laminated block cores, and the magnet insertion holes of each block core are connected by resin passages provided in these intermediate core pieces. By promoting the movement of resin between the magnet insertion holes through the resin passages, the resin can be easily delivered to the ends of each magnet insertion hole even when resin is filled after the block cores are laminated, thereby contributing to the reduction of manufacturing costs.

[0010] The laminated core according to this disclosure is a laminated core formed by further laminating and integrating multiple block cores, each of which is made up of multiple laminated core pieces, wherein the block cores are provided with multiple magnet insertion holes into which permanent magnets are inserted, and the positions of the magnet insertion holes are offset by a predetermined angle for each block core, and one or more intermediate core pieces are arranged between the block cores, each having holes different from those of the block cores, and the intermediate core pieces are provided with resin passages that connect the magnet insertion holes in one adjacent block core to the magnet insertion holes in another adjacent block core.

[0011] As described above, according to this disclosure, a resin passage is provided in an intermediate core piece arranged between block cores, and a predetermined magnet insertion hole in a laminated core obtained by stacking block cores communicates with another magnet insertion hole that is offset from this first magnet insertion hole through the resin passage. As a result, in the resin filling process for the magnet insertion holes, resin can reach all of the magnet insertion holes, and the permanent magnets can be fixed in place by having resin present around the permanent magnets in each magnet insertion hole. Furthermore, resin filling only needs to be performed once for the laminated core obtained by stacking block cores, eliminating the need to fill each block core with resin for fixing permanent magnets, thus improving the efficiency of manufacturing the core using a laminated core.

[0012] This is a schematic diagram illustrating the manufacturing equipment for the laminated core and core portion according to the first embodiment of the present disclosure. This is a plan view of the first block core in the laminated core according to the first embodiment of the present disclosure. This is a plan view of the second block core in the laminated core according to the first embodiment of the present disclosure. This is an enlarged plan view of the main part of the first intermediate core piece in the laminated core according to the first embodiment of the present disclosure. This is an enlarged plan view of the main part of the second intermediate core piece in the laminated core according to the first embodiment of the present disclosure. This is an explanatory diagram illustrating the magnet insertion hole structure of the block core in the laminated core according to the first embodiment of the present disclosure. This is an enlarged plan view of the main part of the laminated core according to the first embodiment of the present disclosure. This is an explanatory diagram illustrating the permanent magnet arrangement state in the first block core in the laminated core according to the first embodiment of the present disclosure. This is an explanatory diagram illustrating the laminated state of the second block core in the laminated core according to the first embodiment of the present disclosure. This is an explanatory diagram illustrating the laminated state of the first block core in the laminated core according to the first embodiment of the present disclosure. This is an explanatory diagram illustrating the resin flow state in the A-A section of Figure 4B. This is a plan view of the core portion obtained from a laminated core according to the first embodiment of this disclosure. This is a side view of the core portion obtained from a laminated core according to the first embodiment of this disclosure. This is an enlarged cross-sectional view of the section B-B in Figure 7A. This is an explanatory diagram of the permanent magnet arrangement on the first block core in a laminated core according to the second embodiment of this disclosure. This is an explanatory diagram of the stacking state of the second block core in a laminated core according to the second embodiment of this disclosure, which is an explanatory diagram of the stacking state of the intermediate core piece on the first block core in a laminated core according to the second embodiment of this disclosure. This is an explanatory diagram of the permanent magnet arrangement on the second block core in a laminated core according to the second embodiment of this disclosure. This is an explanatory diagram of the stacking state of the first block core in a laminated core according to the second embodiment of this disclosure.

[0013] (First Embodiment of the Disclosure) Hereinafter, a laminated core according to the first embodiment of the Disclosure will be described with reference to Figures 1 to 8. In this embodiment, an example of a laminated core that is manufactured by stacking a plurality of core pieces obtained by press punching and that forms the core portion of a rotor in a rotating electric machine will be described.

[0014] In each figure, the laminated core 10 according to this embodiment is configured to include a plurality of block cores 11, 12 formed by stacking a plurality of core pieces 11a, 12a, and intermediate core pieces 17, 18 disposed between each block core 11, 12.

[0015] Of the block cores 11 and 12, the first block core 11 is formed by stacking multiple thin, plate-shaped core pieces 11a made of magnetic metal material. The second block core 12 is formed by stacking multiple thin, plate-shaped core pieces 12a made of magnetic metal material. The core pieces 11a and 12a that make up each block core 11 and 12 are formed by punching out strips of magnetic metal material, such as electromagnetic steel or amorphous alloy, through a press working process. Multiple, preferably three or more, of these block cores 11 and 12 are stacked and integrated with intermediate core pieces 17 and 18 in between to form a laminated core 10.

[0016] The block cores 11 and 12 are configured to have shaft holes 13 and 14 and magnet insertion holes 15 and 16, respectively, which penetrate in the stacking direction of the core pieces 11a and 12a. The shaft holes 13 and 14 are through holes provided in the center of the block cores 11 and 12, through which the rotor's rotation shaft can be inserted and fixed.

[0017] The magnet insertion holes 15 and 16 are holes through which permanent magnets 20 can be inserted, and multiple such holes are provided in a predetermined arrangement along the circular outer circumference of the block cores 11 and 12. The arrangement of the magnet insertion holes 16 in the second block core 12 is offset by a predetermined angle around the shaft hole 14 from the arrangement of the magnet insertion holes 15 in the first block core 11. The position, shape, and number of these magnet insertion holes 15 and 16 can be appropriately set according to the application of the rotating electric machine and the required performance.

[0018] The magnet insertion holes 15 and 16 include magnet placement sections 15a and 16a for positioning the permanent magnet 20, and flux barrier sections 15b and 16b, which are regions that suppress leakage magnetic flux from the permanent magnet 20. The flux barrier sections 15b and 16b exist adjacent to the permanent magnet 20 as regions without magnetic material, and unlike magnetic material, they function to limit magnetic flux, thereby suppressing leakage magnetic flux that does not contribute to torque generation of the permanent magnet 20. This is a known structure, and a detailed explanation is omitted.

[0019] By alternately stacking a first block core 11 and a second block core 12 in which the arrangement of the magnet insertion holes 16 is shifted by a predetermined angle, a skewed structure can be obtained in which the positions of the magnet insertion holes 15 and 16 are shifted for each block core 11 and 12. In the stacked state, the magnet insertion holes 15 of the first block core 11 and the magnet insertion holes 16 of the second block core 12 overlap only in part due to the shift.

[0020] The intermediate core pieces 17 and 18 are formed in a thin plate shape and are arranged one or more times between the block cores 11 and 12. The first intermediate core piece 17 has substantially the same shape as the magnet insertion hole 15 in the adjacent first block core 11 and is provided with a first resin passage 17a, which is a through hole that overlaps with and communicates with the magnet insertion hole 15, and a second resin passage 17b that does not overlap with the magnet insertion hole 15. The second intermediate core piece 18 has substantially the same shape as the magnet insertion hole 16 in the adjacent second block core 12 and is provided with a first resin passage 18a, which is a through hole that overlaps with and communicates with the magnet insertion hole 16, and a second resin passage 18b that does not overlap with the magnet insertion hole 16.

[0021] As these intermediate core pieces 17 and 18 overlap and are arranged between the block cores 11 and 12, parts of the first resin passages 17a and 18a overlap and communicate with each other. Also, parts of the second resin passages 17b and 18b overlap and communicate with each other at positions that do not overlap with either of the magnet insertion holes 15 and 16 in the intermediate core pieces 17 and 18. Thus, the magnet insertion hole 15 in the first block core 11 and the magnet insertion hole 16 in the second block core 12 communicate with each other through the first resin passages 17a and 18a and the second resin passages 17b and 18b.

[0022] The second resin passages 17b and 18b are arranged to connect the magnet insertion hole 15 of the first block core 11 and the magnet insertion hole 16 of the second block core 12, which corresponds to a position shifted by a predetermined angle from the magnet insertion hole 15, in a location where the magnet insertion holes do not overlap. These second resin passages 17b and 18b are required to be provided in the intermediate core pieces 17 and 18 at a location that does not affect electromagnetic properties and strength, and with an axial depth that does not affect electromagnetic properties and strength.

[0023] As a specific example, the second resin passage 17b is provided such that one end is connected to the flux barrier portion 15b of the magnet insertion hole 15 that is closer to the outer circumference of the block core 11. On the other hand, the second resin passage 18b is provided such that one end is connected to the flux barrier portion 16b of the magnet insertion hole 16 that is closer to the outer circumference of the block core 12.

[0024] Of the multiple intermediate core pieces 17 and 18 arranged in stacks, the intermediate core piece 17 closer to the block core 11 has a second resin passage 17b that communicates with the magnet insertion hole 15, but does not communicate with the magnet insertion hole 16 of the block core 12. Conversely, the intermediate core piece 18 closer to the block core 12 has a second resin passage 18b that communicates with the magnet insertion hole 16, but does not communicate with the magnet insertion hole 15 of the block core 11. The second resin passages 17b and 18b of each of these intermediate core pieces 17 and 18 communicate with each other axially at an intermediate position between the magnet insertion hole 15 and the magnet insertion hole 16, so that the second resin passages 17b and 18b as a whole can communicate with each other.

[0025] In addition, the first resin passages 17a and 18a are provided as through holes in the intermediate core pieces 17 and 18 at positions that overlap with the magnet insertion holes 15 of the first block core 11 and the magnet insertion holes 16 of the second block core 12, respectively. Therefore, at the positions where the magnet insertion holes 15 and 16 of each block core 11 and 12 overlap each other, each magnet insertion hole 15 and 16 forms a continuous hole in the axial direction through a portion of the first resin passages 17a and 18a of the intermediate core pieces 17 and 18.

[0026] Furthermore, the intermediate core pieces 17 and 18, like the core pieces 11a and 12a of the block cores 11 and 12, are provided with a shaft hole (not shown) in the center, which is a through hole through which the rotor's rotation shaft can be inserted and fixed. Thus, the intermediate core pieces 17 and 18 are provided with second resin passages 17b and 18b in addition to the first resin passages 17a and 18a and the shaft hole, resulting in a hole arrangement that is partially different from the core pieces 11a and 12a that make up the block cores 11 and 12.

[0027] The manufacturing of the laminated core according to this embodiment is carried out through a press working process and a lamination process. Of these, the press working process is a process of punching out core pieces 11a, 12a and intermediate core pieces 17, 18 from a workpiece 80 made of magnetic metal material. In addition, the press working process includes a process of stacking the punched core pieces 11a, 12a and intermediate core pieces 17, 18 in a laminated state, and integrating a plurality of core pieces 11a, 12a in a laminated state to form block cores 11, 12. The lamination process is a process of stacking the block cores 11, 12 while arranging the intermediate core pieces 17, 18 between these block cores 11, 12 to form a laminated core 10.

[0028] The core portion 1 manufactured using the laminated core according to this embodiment comprises a laminated core 10, permanent magnets 20 arranged in a plurality of magnet insertion holes 15, 16 of the laminated core 10, and a resin 30 for fixing the permanent magnets (see Figures 7A, 7B, and 8). This core portion 1 has a known structure as a key part of the rotor in a rotating electric machine (electric motor or generator), and a detailed explanation is omitted.

[0029] The permanent magnets 20 are used as field magnets for the rotor and are inserted into the magnet insertion holes 15 and 16 of each block core 11 and 12 through a magnet insertion process. These permanent magnets 20 are formed to be slightly smaller than the magnet placement portions 15a and 16a of the magnet insertion holes 15 and 16. Therefore, when the permanent magnets 20 are inserted into the magnet insertion holes 15 and 16, a gap is created between the permanent magnets 20 and the block cores 11 and 12. In other words, each magnet insertion hole 15 and 16 into which the permanent magnets 20 have been inserted remains partially empty. The remaining portion of these magnet insertion holes 15 and 16, excluding the permanent magnets 20, is filled with resin 30.

[0030] The resin 30 is injected and filled in a molten state into the magnet insertion holes 15 and 16, more specifically into the remaining portion of the magnet insertion holes 15 and 16 after the permanent magnet 20 has been inserted. After filling, it solidifies to fix the permanent magnet 20 in place. The resin 30 is, for example, a thermosetting resin such as epoxy resin or a thermoplastic resin, and one or more types of resin materials supplied as resin tablets or powdered resin are melted and filled into the magnet insertion holes 15 and 16.

[0031] These core parts 1 are manufactured through a magnet insertion process and a resin filling process, which are carried out in parallel with the lamination process of the laminated iron core 10. The magnet insertion process involves inserting permanent magnets 20 into the magnet insertion holes 15 and 16 in the block iron cores 11 and 12. The resin filling process involves filling the gaps between the permanent magnets 20 and the laminated iron core 10, which are the remaining parts of the magnet insertion holes 15 and 16 of the laminated iron core 10 obtained by laminating the block iron cores 11 and 12, excluding the permanent magnets 20 in the magnet insertion holes 15 and 16, with resin 30.

[0032] Next, the manufacturing of the laminated iron core and the core portion using the present embodiment will be described. First, as a press working process, a processing device 91 performs a progressive die-cutting process on a strip-shaped workpiece 80 that is conveyed intermittently, using its die. In the progressive die-cutting process, punching is performed in multiple stages, and the shapes of the iron core pieces 11a, 12a and intermediate iron core pieces 17, 18 are formed in the target areas of the workpiece 80. For example, punching is performed on the iron core pieces 11a, 12a to form through holes corresponding to the axial holes 13, 14 and magnet insertion holes 15, 16, respectively. Finally, in the last stage of the progressive die-cutting process, the target areas are punched out from the workpiece 80 and separated as iron core pieces 11a, 12a and intermediate iron core pieces 17, 18.

[0033] Furthermore, the punching of the core pieces 11a, 12a and intermediate core pieces 17, 18, each with different detailed shapes, can be handled by adjusting the movement of a part of the die in the processing device 91 when switching to a different punching method after repeating the same punching a specified number of times. Also, if the punching shapes of the intermediate core pieces 17, 18 differ for each intermediate core piece 17, 18 due to the structure of the first resin passage and the second resin passage, this can also be handled by adjusting the movement of a part of the die in the processing device 91 each time the punching shape is changed.

[0034] The mechanisms of this processing apparatus 91 that perform multiple stages of punching on the intermittently conveyed workpiece 80 using progressive die-cutting are the same as those of known press working apparatuses used in progressive die-cutting press working, and therefore a detailed explanation is omitted.

[0035] The processing apparatus 91 has a mechanism for performing progressive processing, as well as a known mechanism that can temporarily hold the punched core pieces 11a, 12a and intermediate core pieces 17, 18 in a stacked state. Each time a new core piece 11a, 12a or intermediate core piece 17, 18 is punched out and stacked, these core pieces 11a, 12a or intermediate core pieces 17, 18 move downward while maintaining their stacked state. When the stacked number (thickness) of the stacked core pieces 11a, 12a or intermediate core pieces 17, 18 reaches a specified value, the lower stack of core pieces 11a, 12a or intermediate core pieces 17, 18 is sent to the next process by a predetermined transfer mechanism 71 while still in its stacked state. By stacking the intermediate core pieces 17 and 18 together with the core pieces 11a and 12a, and maintaining the arrangement relationship of the stacked state throughout each manufacturing process, the intermediate core pieces 17 and 18 can be easily positioned between the block cores 11 and 12, which are made up of core pieces 11a and 12a.

[0036] Of the stacked pieces, the core pieces 11a and 12a are subjected to adjustments such as rolling as necessary, and then integrated into a block core 11 and 12 in a stacked state. Alternatively, the processing device 91 may integrate each core piece by crimping or the like while stacking the core pieces 11a and 12a, and then feed out the stacked core pieces 11a and 12a as a block core 11 and 12.

[0037] In this embodiment, one core piece 11a is punched out from the workpiece 80 by progressive die stamping and stacked. When the number of these core pieces 11a reaches a number equivalent to that of a block core, the processing device 91 adjusts the movement of a part of the die and then proceeds to punch out the first intermediate core piece 17. By adjusting a part of the die, the first intermediate core piece 17 is made to have a different shape from the core pieces 11a and 12a that form the block cores 11 and 12 through progressive die stamping. Once the first intermediate core piece 17 is punched out and stacked, the process moves on to punching out the second intermediate core piece 18. In this way, the intermediate core pieces 17 and 18 are punched out, and when their number reaches a preset number, the processing device 91 adjusts a part of the die and then proceeds to punch out the other core piece 12a.

[0038] Furthermore, the core pieces 12a are punched out and stacked by progressive die stamping, and when the number of these core pieces 12a reaches the number equivalent to a block core, the processing device 91 adjusts a part of the die and then moves on to punching out a second intermediate core piece 18. Once the second intermediate core piece 18 is punched out and stacked, the process moves on to punching out the first intermediate core piece 17. In this way, the intermediate core pieces 17 and 18 are punched out, and when the number of these pieces reaches a preset number, the processing device 91 adjusts a part of the die and then returns to punching out one of the core pieces 11a. The same procedure is repeated thereafter.

[0039] In this way, a state is obtained in which intermediate core pieces 17 and 18 are interposed between multiple core pieces 11a and 12a corresponding to each block core 11 and 12 that make up the laminated core 10. Note that, after punching out the number of core pieces 11a and 12a that make up the laminated core, the transition from punching out the core pieces 11a and 12a to punching out the intermediate core pieces 17 and 18 is omitted, and the punching out of the next core piece is started without delay. As a result, the intermediate core pieces 17 and 18 are not mistakenly placed above the core pieces 11a and 12a corresponding to the top of the laminated core 10, or below the core pieces 11a and 12a corresponding to the bottom of the laminated core 10.

[0040] For the intermediate core pieces 17 and 18 that are punched out following the core pieces 11a and 12a, it is also possible to have the multiple core pieces 11a and 12a that were stacked immediately beforehand integrated as block cores 11 and 12, and then stacked on top of these block cores 11 and 12. In this case, when the number of stacked intermediate core pieces 17 and 18 reaches a predetermined number, the stacked intermediate core pieces 17 and 18 are sent to the next process together with the lower block cores 11 and 12. Alternatively, core pieces 11a and 12a can be sequentially stacked on top of the intermediate core pieces 17 and 18, and then these core pieces 11a and 12a can be integrated as block cores 11 and 12, and these block cores 11 and 12 can be sent to the next process together with the lower intermediate core pieces 17 and 18.

[0041] In the lamination process following the press working process, the first block core 11, which is formed by laminating and integrating multiple core pieces 11a, and the second block core 12, which is formed by laminating and integrating multiple core pieces 12a, are alternately laminated with intermediate core pieces 17 and 18 in between, as they reach the lamination position of the insertion device 92. In parallel with this lamination process, the magnet insertion process for the core is performed. In the magnet insertion process, at the magnet insertion position, which also serves as the lamination position of the block cores 11 and 12, permanent magnets 20 are inserted and positioned into the magnet insertion holes 15 and 16 by the insertion device 92.

[0042] The insertion device 92 that executes the magnet insertion process is a device that inserts and arranges the permanent magnets 20 held in advance into the magnet insertion holes 15 and 16 of the block cores 11 and 12 from the axial direction (core piece lamination direction) of the block cores 11 and 12.

[0043] Regarding each mechanism of such an insertion device 92 that inserts and arranges the permanent magnets 20 with respect to the block cores 11 and 12, it is the same as a known device that inserts and arranges a permanent magnet for field excitation into the holes of a laminated core used for a rotor or a stator of a rotating electric machine, and a detailed description thereof will be omitted.

[0044] In the lamination process and the magnet insertion process, first, the first block core 11 forming the end of the laminated core 10 and the first intermediate core piece 17 overlapping it reach the magnet insertion position. Here, the permanent magnet 20 is inserted into the magnet insertion hole 15 through the through-hole portion forming the first resin passage 17a of the first intermediate core piece 17 by the insertion device 92 (see FIG. 5A). After the permanent magnet 20 is inserted, the second block core 12 in which the second intermediate core pieces 18 are laminated integrally up and down is laminated on the upper side of the first intermediate core piece 17 overlapping the first block core 11 (see FIG. 5B).

[0045] As the second block core 12 is laminated on the upper side of the first block core 11 and the first intermediate core piece 17, the permanent magnet 20 can be inserted into each magnet insertion hole 16. The second intermediate core pieces 18 are laminated in advance above and below the second block core 12, and the permanent magnet 20 is inserted into the magnet insertion hole 16 of the second block core 12 by the insertion device 92 through the through-hole portion forming the first resin passage 18a of the intermediate core piece 18 (see FIG. 5C). After the permanent magnet 20 is inserted, the first block core 11 is newly laminated on the upper side of the second intermediate core piece 18 overlapping the second block core 12 in a state where the first intermediate core pieces 17 are laminated integrally above and below it, and the permanent magnet 20 can be inserted into each magnet insertion hole 15 (see FIG. 5D).

[0046] With respect to this first block core 11 as well, the insertion device 92 inserts the permanent magnet 20 into the magnet insertion hole 15 through the through-hole portion forming the first resin passage 17a of the first intermediate core piece 17, similar to the first first block core 11. After inserting the permanent magnet 20, the second block core 12 is newly laminated on the upper side of the first intermediate core piece 17 overlapping the first block core 11 in a state where the second intermediate core piece 18 is laminated and integrated on its lower side, and the permanent magnet 20 can be inserted into the magnet insertion hole 16. For this second block core 12, the permanent magnet 20 is inserted into each magnet insertion hole 16 by the insertion device 92.

[0047] In this way, the block cores 11 and 12 are laminated while interposing the intermediate core pieces 17 and 18, and the permanent magnet 20 is inserted into each of the magnet insertion holes 15 and 16. Then, when the block cores 11 and 12 with the permanent magnets inserted are laminated alternately in two layers at a time, the lamination process and the magnet insertion process are completed. These laminated block cores 11 and 12 and intermediate core pieces 17 and 18 are sent out to the next process by the transfer mechanism 72 as an integrated laminated core 10 (see FIG. 1).

[0048] In the magnet insertion process, if necessary, after inserting and arranging the permanent magnet 20 with respect to the block cores 11 and 12, the entire laminated core 10 is preheated together with the permanent magnet 20, or the preheated permanent magnet 20 is inserted and arranged with respect to the preheated block cores 11 and 12. The laminated core 10 at a temperature suitable for resin filling is sent to the resin filling process by the transfer mechanism 72 together with the permanent magnet 20 housed in the magnet insertion holes 15 and 16.

[0049] In the resin filling process following the lamination process and the magnet insertion process, the filling device 93 fills the resin 30 into the magnet insertion holes 15 and 16 of the laminated core 10 composed of the block cores 11 and 12 and the intermediate core piece 18 to fix the permanent magnet 20 in the magnet insertion holes 15 and 16.

[0050] The filling device 93 is a device that clamps the laminated iron core 10 from both sides in the axial direction to close each opening, and then fills the magnet insertion holes 15 and 16 of the laminated iron core 10 with resin that has been heated and melted. The mechanisms of this filling device 93 for filling the magnet insertion holes 15 and 16 of the laminated iron core 10 with resin 30 are the same as those of known devices that fill holes and gaps in laminated iron cores used in rotors and stators of rotating electric machines with resin for fixing permanent magnets, so a detailed explanation is omitted.

[0051] In the resin filling process, the laminated core 10 with the permanent magnets already inserted is first brought into the filling device 93. The filling device 93 clamps and presses the laminated core 10 from both sides in the lamination direction, closing the openings at both ends of the laminated core 10 in the lamination direction, except for a portion of the magnet insertion holes 15 and 16. In addition, the resin material contained and held in the filling device 93 is heated at an appropriate time and melted into molten resin.

[0052] The filling device 93 isolates each magnet insertion hole 15, 16 of the laminated core 10 from the outside by blocking it, and then resin is injected into the magnet openings 16 that are not blocked. The molten resin is extruded from the filling device 93 towards the laminated core 10 and injected and filled into each magnet insertion hole 15, 16 at one end of the axial direction of the laminated core 10.

[0053] At the point where the magnet insertion holes 15 and 16 overlap in adjacent block cores 11 and 12, the resin advances axially through the first resin passages 17a and 18a of the intermediate core pieces 17 and 18 that overlap with the magnet insertion holes 15 and 16, reaching the other axial end of the laminated core 10. Then, starting from this point where the magnet insertion holes 15 and 16 overlap, the resin moves laterally and gradually enters the other parts of each magnet insertion hole 15 and 16.

[0054] Where the magnet insertion holes 15 and 16 do not overlap in adjacent block cores 11 and 12, the resin first advances axially through the flux barrier portion 16b of the magnet insertion hole 16 at the axial end, which has less resistance to resin flow and is located closer to the outer circumference of the core, and reaches the intermediate core piece 18. Then, starting from this flux barrier portion 16b, the resin gradually enters other parts of the magnet insertion hole 16.

[0055] Furthermore, the resin enters the second resin passage 18b from the flux barrier portion 16b, through the first resin passage 18a of the second intermediate core piece 18 which is in communication with the flux barrier portion 16b. The resin then enters the second resin passage 17b of the first intermediate core piece 17 which overlaps with the second resin passage 18b, and then proceeds through the first resin passage 17a to the flux barrier portion 15b of the magnet insertion hole 15 in the other block core 11. The resin fills this flux barrier portion 15b and proceeds from the flux barrier portion 15b to the parts of the other magnet insertion holes 15 that do not have permanent magnets 20, and further reaches the first resin passage 17a and the second resin passage 17b of the first intermediate core piece 17.

[0056] From this point onward, the resin enters the flux barrier portion 16b of the magnet insertion hole 16 through the flux barrier portion 15b of the magnet insertion hole 15, the second resin passage 17b of the first intermediate core piece 17, and the second resin passage 18b of the second intermediate core piece 18. The resin then proceeds from this flux barrier portion 16b to the other parts of the magnet insertion hole 16 that do not contain permanent magnets 20. Furthermore, the resin enters the flux barrier portion 15b of the magnet insertion hole 15 through the second resin passage 18b of the second intermediate core piece 18 and the second resin passage 17b of the first intermediate core piece 17. From there, the resin proceeds to the other parts of the magnet insertion hole 15 that do not contain permanent magnets 20. Finally, when the resin fills the parts of each magnet insertion hole 15 and 16 that do not contain permanent magnets 20, the filling is complete.

[0057] In the magnet insertion holes 15 and 16, the ends that did not overlap with the other magnet insertion holes 16 and 15 were in a state where resin flow was difficult. However, the second resin passages 17b and 18b of the intermediate iron core pieces 17 and 18 connect the magnet insertion holes 15 and 16, allowing the resin to flow between the holes via the second resin passages 17b and 18b. Consequently, it becomes easier for the resin to reach every corner of the parts of each magnet insertion hole 15 and 16 that do not have permanent magnets 20.

[0058] In particular, the second resin passages 17b and 18b are connected to the flux barrier portions 15b and 16b, which are often located at the ends of the magnet insertion holes 15 and 16 and do not contain permanent magnets 20, among the non-overlapping portions of the magnet insertion holes 15 and 16. As a result, a communication channel is created from the flux barrier portion 16b in the magnet insertion hole 16 of the block core 12 located at the axial end of the laminated core 10, passing through the second resin passages 17b and 18b and the flux barrier portions of the other block cores, respectively. This allows the resin to flow quickly in the axial direction of the laminated core 10 through the communication channel consisting of the flux barrier portions 15b and 16b and the second resin passages 17b and 18b, enabling more efficient distribution of the resin to each portion of each magnet insertion hole 15 and 16.

[0059] Even after resin filling, the filling device 93 maintains a closed state by clamping and pressing the laminated iron core 10, allowing the solidification of the molten resin located in each magnet insertion hole 15, 16 to proceed. Once the molten resin has solidified into solidified resin 30, and the permanent magnets 20 are fixed to the laminated iron core 10, the core portion 1 is obtained. The core portion 1 is then removed from the filling device 93 after the clamping and pressing is completed. The core portion 1 removed from the filling device 93 is then transferred to the next process by the transfer mechanism 73.

[0060] As described above, in the laminated core according to this embodiment, second resin passages 17b and 18b are provided in the intermediate core pieces 17 and 18 arranged between the block cores 11 and 12. Through these second resin passages 17b and 18b, the magnet insertion hole 15 in the laminated core 10 obtained by laminating the block cores 11 and 12 communicates with another magnet insertion hole 16 which is offset from the first magnet insertion hole 15. As a result, in the resin filling process for the magnet insertion holes 15 and 16, resin can reach the magnet insertion holes 15 and 16 of either block core 11 or 12, and the permanent magnet 20 can be fixed in place by having resin present around the permanent magnet 20 in each magnet insertion hole 15 or 16. Furthermore, resin filling only needs to be performed once for the laminated core 10 obtained by laminating the block cores 11 and 12, eliminating the need to perform resin filling for fixing the permanent magnet 20 for each block core 11 or 12, thus improving the efficiency of core manufacturing using the laminated core 10.

[0061] In this embodiment, the laminated core is constructed by alternately stacking two blocks of core 11 and 12 in alternating layers, with intermediate core pieces 17 and 18 interposed between them, to form a total of four layers of block cores 11 and 12, thereby creating the laminated core 10. However, the invention is not limited to this configuration, and a laminated core can be constructed by stacking three blocks of core, or by stacking five or more blocks of core.

[0062] Furthermore, in the laminated core according to this embodiment, two intermediate core pieces 17 and 18 are arranged in stacks between the block cores 11 and 12, and holes of different shapes are connected to each intermediate core piece 17 and 18 to create second resin passages 17b and 18b, but the invention is not limited to this configuration. For example, it is also possible to arrange only one intermediate core piece between the block cores 11 and 12, or to arrange three or more pieces in stacks. However, when only one intermediate core piece is arranged, it is desirable to provide holes corresponding to the magnet insertion holes 15 and 16, and to provide a resin passage that communicates with both the magnet insertion holes 15 and 16, so that the resin passage is located in a position that does not reduce the strength of the intermediate core piece.

[0063] Furthermore, in the laminated core according to this embodiment, the axial holes 13 and 14 in each block core 11 and 12 have a common shape, while the shapes of the core pieces 11a and 12a are changed to obtain a skew structure, thereby forming two types of block cores 11 and 12 in a laminated structure. These block cores 11 and 12 are then alternately laminated to form the laminated core 10. However, the embodiment is not limited to this.

[0064] For example, suppose a mounting structure for the block core to the shaft is adopted that allows for the secure integration of the block core with the shaft even if the angle of each block core is shifted. In this way, it is possible to form a laminated core with a skew structure by stacking multiple block cores, all of which are made from the same core pieces and all of the same shape, and then stacking them with a shifted angle for each block core.

[0065] As a specific example, the mounting structure for the block core to the shaft can be a combination of a splined shaft and splined holes on the core side, and the angle at which the block core is shifted to create a skewed structure should match the pitch angle of the spline tooth profile or a multiple thereof. If the block core and the core pieces that make it up are all the same shape, a significant reduction in the manufacturing cost of the laminated core can be achieved.

[0066] Furthermore, in the manufacturing of the laminated core according to this embodiment, the core pieces 11a, 12a and the intermediate core pieces 17, 18 are continuously formed in the press working process by punching them out from the same workpiece 80 using the same processing equipment. A laminated state is obtained in which the intermediate core pieces 17, 18 are interposed between the multiple core pieces 11a corresponding to the first block core 11 and the multiple core pieces 11a corresponding to the second block core 12, and the intermediate core pieces 17, 18 are left interposed between the block cores 11, 12 in this manner. However, this is not the only way, and the state in which the intermediate core pieces exist between the core pieces may be created at a stage after punching.

[0067] For example, in the press working process, only the punching of core pieces 11a and 12a is performed on the workpiece 80, and the formation of the intermediate core piece is carried out in a separate manufacturing process. However, during the transfer of the block cores 11 and 12 to the lamination process and the magnet insertion process, the intermediate core piece is merged into the transfer path so that it is transferred overlapping the upper or lower side of the block cores 11 and 12. This makes it possible to seamlessly maintain the intermediate core piece interposed between the block cores when the block cores 11 and 12 are sequentially stacked in a later process.

[0068] Furthermore, in the laminated core according to this embodiment, the core pieces 11a, 12a and the intermediate core pieces 17, 18 are formed by punching out the same workpiece 80, and the intermediate core pieces 17, 18 are made to the same thickness as the core pieces 11a, 12a, but the invention is not limited to this. For example, even if the intermediate core pieces are made to be thicker than the individual core pieces, and the holes that serve as resin passages are made to be large holes that allow resin to pass through easily, or multiple such holes are provided, sufficient strength can be maintained, and resin filling can be carried out efficiently.

[0069] (Second Embodiment of the Present Disclosure) In the manufacturing of the laminated core according to the first embodiment, the core pieces 11a, 12a and the intermediate core pieces 17, 18 are formed consecutively in a press working process by punching them out from the same workpiece 80 using the same processing apparatus. A laminated state is obtained in which the intermediate core pieces 17, 18 are interposed between a plurality of core pieces 11a corresponding to the first block core 11 and a plurality of core pieces 12a corresponding to the second block core 12, and the intermediate core pieces 17, 18 are left interposed between the block cores 11, 12. However, the invention is not limited to this, and in the second embodiment, the intermediate core pieces 17, 18 are formed separately from the core pieces 11a, 12a, and are first placed between the block cores 11, 12 in the lamination process in which the block cores 11, 12 are laminated. However, as a prerequisite, in the press working process preceding the lamination process, only the core pieces 11a and 12a are punched out from the workpiece 80, and the intermediate core pieces 17 and 18 are not punched out in between the punching operations. Consequently, in the laminated state where the punched core pieces 11a and 12a are stacked, the intermediate core pieces 17 and 18 do not overlap the core pieces 11a and 12a.

[0070] In the lamination and magnet insertion processes of the manufacturing of the laminated core 10, when the first block core 11, which forms the end of the laminated core 10, reaches the magnet insertion position which also serves as the lamination position, the insertion device 92 inserts permanent magnets 20 into the magnet insertion holes 15 (see Figure 9A). After the permanent magnets 20 have been inserted, separately formed intermediate core pieces 17 and 18 are brought in and stacked on top of the block core 11, and then the second block core 12 is further laminated (see Figures 9B and 9C). For this second block core 12 as well, the insertion device 92 inserts permanent magnets 20 into each magnet insertion hole 16 of the second block core 12 (see Figure 9D). After the permanent magnets 20 have been inserted, intermediate core pieces 17 and 18 are brought in and stacked on top of the second block core 12, and the first block core 11 is newly laminated on top of these intermediate core pieces 17 and 18 (see Figures 10A and 10B). The insertion device 92 also inserts permanent magnets 20 into the magnet insertion holes 15 of the first block core 11 (see Figure 10C). After the permanent magnets 20 are inserted, intermediate core pieces 17 and 18 are brought in and stacked on top of the first block core 11, and a new second block core 12 is stacked on top of these intermediate core pieces 17 and 18. Permanent magnets 20 are then inserted into each magnet insertion hole 16 of this second block core 12 by the insertion device 92.

[0071] As the block cores 11 and 12 are stacked, intermediate core pieces 17 and 18 are placed on each block core 11 and 12, thereby arranging the intermediate core pieces 17 and 18 between the block cores 11 and 12. At the same time, each time the block cores 11 and 12 are stacked, a permanent magnet 20 is inserted into each magnet insertion hole 15 and 16. When the block cores 11 and 12 with permanent magnets inserted are stacked alternately in two layers each, the stacking process and the magnet insertion process are completed. The stacked block cores 11 and 12 and the intermediate core pieces 17 and 18 are sent to the next process as a single stacked core 10, similar to the first embodiment. In the manufacturing of the stacked core according to this second embodiment, the resin filling process that follows the stacking process and the magnet insertion process is the same as in the first embodiment, and a detailed explanation is omitted.

[0072] In this way, the intermediate core pieces 17 and 18 are formed separately from the core pieces 11a and 12a, transported along a different route than the core pieces 11a and 12a, and placed on top of the block cores 11 and 12 as each block core is stacked, thus being positioned between the block cores. This allows the manufacturing of the core pieces 11a and 12a and the intermediate core pieces 17 and 18 to be carried out without constraints such as the need for equipment commonality or timing adjustments, and increases the degree of freedom in manufacturing, such as allowing for staggered manufacturing timings.

[0073] (1) A laminated iron core formed by further stacking and integrating multiple block iron cores, each block iron core having multiple stacked iron core pieces, wherein the block iron cores are provided with multiple magnet insertion holes into which permanent magnets are inserted, and the positions of the magnet insertion holes in each block iron core are stacked in such an arrangement that they are offset by a predetermined angle, and one or more intermediate iron core pieces are arranged between the block iron cores, each having holes different from those of the block iron cores, and the intermediate iron core pieces are provided with resin passages that connect the magnet insertion holes in one adjacent block iron core to the magnet insertion holes in another adjacent block iron core. (2) The laminated iron core according to (1), wherein the resin passages of the intermediate iron core pieces are arranged to connect the magnet insertion holes in one block iron core to predetermined magnet insertion holes in the other block iron cores that correspond to the positions where the magnet insertion holes are offset by the aforementioned angle, in a portion where the magnet insertion holes do not overlap. (3) A laminated core as described in (2) above, wherein the magnet insertion hole consists of a combination of a magnet arrangement portion into which the permanent magnet is inserted and a flux barrier portion adjacent to the magnet arrangement portion, and the resin passage of the intermediate core piece is provided in such an arrangement that it connects the flux barrier portion of the magnet insertion hole in one block core with the flux barrier portion of the magnet insertion hole in the other block core. (4) A laminated core as described in any of (1) to (3) above, wherein the intermediate core piece is provided with a through hole as part of the resin passage at a position where at least the magnet insertion hole in one block core and the magnet insertion hole in the other block core overlap. (5) A laminated core according to any one of (1) to (4) above, characterized in that the intermediate core piece is provided with a through hole as part of the resin passage at least at one of the positions where it overlaps with the magnet insertion hole in one block core and where it overlaps with the magnet insertion hole in the other block core.(6) A method for manufacturing a laminated iron core, wherein a block iron core, in which a plurality of iron core pieces are stacked, is further stacked and integrated to form a laminated iron core, comprising the step of stacking the block iron cores, each having a plurality of magnet insertion holes into which permanent magnets are inserted, in such an arrangement that the positions of the magnet insertion holes are shifted by a predetermined angle for each block iron core, one or more intermediate iron core pieces different from the iron core pieces are arranged between the block iron cores, and the intermediate iron core pieces are provided with resin passages that connect the magnet insertion holes in one adjacent block iron core to the magnet insertion holes in another adjacent block iron core. (7) A method for manufacturing a laminated core as described in (6), characterized in that the core pieces are continuously punched out and stacked using a punching processing device, the intermediate core pieces are punched out by the processing device at limited timings set between punching out the core pieces, stacked in the same way as the core pieces, and positioned between a plurality of core pieces that will form the block core even before the step of stacking the block core. (8) A method for manufacturing a laminated core as described in (6), characterized in that the intermediate core pieces are formed separately from the core pieces, and in the step of stacking the block core, the intermediate core pieces are transferred and placed on the block core each time a block core is stacked.

Claims

1. A laminated iron core formed by further stacking and integrating multiple block iron cores, each block iron core having multiple magnet insertion holes into which permanent magnets are inserted, wherein the block iron cores are provided with multiple magnet insertion holes into which permanent magnets are inserted, and the positions of the magnet insertion holes are offset by a predetermined angle for each block iron core, and one or more intermediate iron core pieces having holes different from those of the block iron cores are arranged between the block iron cores, and the intermediate iron core pieces are provided with resin passages that connect the magnet insertion holes in one adjacent block iron core to the magnet insertion holes in another adjacent block iron core.

2. A laminated core according to claim 1, characterized in that the resin passage of the intermediate core piece is arranged to communicate with the magnet insertion hole in one block core and a predetermined magnet insertion hole in the other block core, which corresponds to a position where the magnet insertion hole is offset by the angle, at a portion where the magnet insertion holes do not overlap.

3. A laminated core according to claim 2, wherein the magnet insertion hole consists of a combination of a magnet arrangement portion in which the permanent magnet is inserted and a flux barrier portion adjacent to the magnet arrangement portion, and the resin passage of the intermediate core piece is provided in such an arrangement that it connects the flux barrier portion of the magnet insertion hole in one block core with the flux barrier portion of the magnet insertion hole in the other block core.

4. A laminated core according to claim 1, characterized in that the intermediate core piece is provided with a through hole as part of the resin passage at a position where the magnet insertion hole in at least one block core and the magnet insertion hole in the other block core overlap.

5. A laminated core according to claim 1, characterized in that the intermediate core piece is provided with a through hole as part of the resin passage at at least one of the positions where it overlaps with the magnet insertion hole in one block core and where it overlaps with the magnet insertion hole in the other block core.

6. A method for manufacturing a laminated iron core, comprising stacking and integrating multiple block iron cores, each having multiple stacked iron core pieces, the method comprising the step of stacking the block iron cores, each having multiple magnet insertion holes into which permanent magnets are inserted, in such an arrangement that the positions of the magnet insertion holes are shifted by a predetermined angle for each block iron core, one or more intermediate iron core pieces different from the iron core pieces are arranged between the block iron cores, and the intermediate iron core pieces are provided with resin passages that connect the magnet insertion holes in one adjacent block iron core to the magnet insertion holes in another adjacent block iron core.

7. A method for manufacturing a laminated iron core according to claim 6, characterized in that the iron core pieces are continuously punched out and laminated using a punching processing device, and the intermediate iron core pieces are punched out by the processing device at limited timings set as intervals between punching out the iron core pieces, laminated in the same manner as the iron core pieces, and positioned between a plurality of iron core pieces that will form the block core, prior to the process of laminating the block core.

8. A method for manufacturing a laminated iron core according to claim 6, characterized in that the intermediate iron core piece is formed separately from the iron core piece, and in the step of laminating the block iron core, the intermediate iron core piece is transferred and placed on the block iron core each time a block iron core is stacked.

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