Laminated iron core and method for manufacturing the same

Abstract

To provide a laminated iron core that can reliably suppress the generation of vibrations when the laminated iron core rotates. [Solution] The laminated iron core 1 comprises multiple blocks 3 stacked with a phase shift of less than 180 degrees. The angles of the multiple blocks 3 are set according to the eccentricity distance of the centroids G1 to G6 of the multiple blocks 3 with respect to the radial center C1 and the arrangement distance with respect to the center C2 in the stacking direction, thereby adjusting the rotational imbalance caused by the eccentricity of the multiple blocks 3.

Description

Technical Field

[0001] The present invention relates to a laminated core used for an electric motor or the like and a method for manufacturing the same.

Background Art

[0002] As a conventional laminated core, there is one formed by laminating a plurality of blocks while shifting their phases, as in Patent Document 1.

[0003] Each block is formed by laminating a plurality of core pieces punched from an electromagnetic steel sheet. The electromagnetic steel sheet has a thickness deviation and is not completely uniform in thickness. Therefore, the core pieces also have a thickness deviation, which causes an eccentricity, which is a shift of the center of gravity with respect to the center in the radial direction of the block.

[0004] Therefore, the conventional laminated core is formed by laminating two core portions, which are laminated while alternately shifting the plurality of blocks by 180 degrees each, such that the end faces in the lamination direction abut against each other. The two core portions of the laminated core are arranged such that the state of the shift of the blocks is plane-symmetric with respect to the end faces that abut against each other.

[0005] With such a configuration, the conventional laminated core can theoretically make the force caused by the eccentricity of the block zero during rotation, and the vibration during rotation is suppressed.

[0006] However, the electromagnetic steel sheet has magnetic anisotropy such that, for example, the magnetic properties in the rolling direction and the direction perpendicular thereto are different. Therefore, simply laminating the two core portions, which are laminated while alternately shifting the blocks by 180 degrees each as described above, such that the end faces in the lamination direction abut against each other in a plane-symmetric manner leaves magnetic anisotropy in the laminated core, and vibration may occur during rotation of the laminated core.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

[0008] The problem we are trying to solve is that vibration occurs during rotation due to the anisotropy of the magnetic properties of the laminated iron core. [Means for solving the problem]

[0009] The present invention provides a laminated iron core comprising a plurality of blocks stacked with a phase shift of less than 180 degrees, wherein the angle of the plurality of blocks is set according to the eccentricity distance of the centroids of the plurality of blocks with respect to the radial center and the arrangement distance with respect to the center in the stacking direction, thereby adjusting the rotational imbalance due to the eccentricity of the plurality of blocks. [Effects of the Invention]

[0010] According to the present invention, the generation of vibrations during the rotation of the laminated iron core can be reliably suppressed. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a schematic diagram of the laminated iron core according to Embodiment 1 of the present invention. [Figure 2] Figure 2 is a schematic diagram showing the center of gravity and eccentricity of the laminated iron core in Figure 1. [Figure 3] Figure 3 is a perspective vector diagram of the eccentric model of the laminated iron core block shown in Figure 1. [Figure 4] Figure 4 is a front view vector diagram of the eccentric model in Figure 1. [Modes for carrying out the invention]

[0012] The objective of reliably suppressing vibrations during the rotation of the laminated iron core was achieved by shifting the phases of the multiple stacked blocks by an angle of less than 180 degrees, thereby adjusting the rotational imbalance caused by the eccentricity of the multiple blocks.

[0013] In other words, the laminated iron core 1 comprises multiple blocks 3 stacked with a phase shift of less than 180 degrees. The phase shift angle of the multiple blocks 3 is set according to the eccentricity distance of the centroids G1 to G6 of the multiple blocks 3 with respect to the radial center C1 and the arrangement distance with respect to the center C2 in the stacking direction, thereby adjusting the rotational imbalance caused by the eccentricity of the multiple blocks 3.

[0014] In one embodiment, the number of blocks 3 may be six or more, and the centroids G1 and G6; G2 and G5; G3 and G4 of blocks 3 that are at the same distance from the center C2 in the stacking direction may be eccentric in the same direction with respect to the center C1 in the radial direction, and at least a portion of the centroids G1 to G6 of the blocks 3 may be arranged in different phases on each side of the center C2 in the stacking direction.

[0015] Furthermore, the eccentricity distances of multiple blocks 3 may be the same. In this case, the centroids G1 to G6 of the blocks 3 are arranged at predetermined angle intervals in the circumferential direction on both sides of the stacking center C2.

[0016] Such a predetermined angle is less than 180 degrees and can be defined as θ = (360 ÷ N / 2) × m. In this formula, N is the number of stacked blocks 3, and m is any integer greater than or equal to 1.

[0017] It is preferable that the multiple blocks 3 have the same height in the stacking direction.

[0018] Block 3 may be stacked on one side of the stacking center C2 with a phase shift in one direction, while Block 2 may be stacked on the other side of the stacking center C2 with a phase shift in the opposite direction. In this case, the adjacent Block 3 on one side and the adjacent Block 3 on the other side, with respect to the stacking center C2, are in the same phase.

[0019] The manufacturing method of the laminated core 1 is to stack the blocks 3 while shifting the phase in one direction on one side with respect to the center C2 in the stacking direction, and stack the blocks 3 having the same phase as the adjacent block 3 on one side sandwiching the center in the stacking direction on the other side with respect to the center C2 in the stacking direction, and then stack the subsequent blocks 3 while shifting the phase in the other direction opposite to the one direction.

Example

[0020] [Configuration of laminated core] FIG. 1 is a schematic configuration diagram of a laminated core according to Embodiment 1 of the present invention. FIG. 2 is a schematic diagram showing the center of gravity and its eccentricity of the laminated core of FIG. 1. FIG. 3 is a perspective vector diagram of an eccentricity model of the blocks of the laminated core of FIG. 1. FIG. 4 is a front vector diagram of the eccentricity model of FIG. 1.

[0021] The laminated core 1 of FIG. 1 is used for a rotor core of an electric motor or a generator. This laminated core 1 includes a plurality of blocks 3 stacked while shifting the phase. The number of the plurality of stacked blocks 3 is six in this embodiment, but it can also be seven or more. However, the number of the plurality of blocks 3 can be arbitrarily set as long as the rotational imbalance is adjusted for the entire laminated core 1.

[0022] In the laminated core 1 of this embodiment, the blocks 3 are stacked while shifting the phase in one direction on one side with respect to the center C2 in the stacking direction, and the blocks 2 are stacked while shifting the phase in the other direction opposite to the one direction on the other side with respect to the center C2 in the stacking direction. And the block 3 on one side and the block 3 on the other side adjacent to each other across the center C2 in the stacking direction have the same phase.

[0023] The process of stacking multiple blocks 3 with their phases shifted is called shift stacking. The phase of a block 3 is the circumferential position of an arbitrary reference point of the block 3, and refers to the circumferential rotation state of the block 3. The phase shift of multiple blocks 3 is the shift of the corresponding reference points of the blocks 3, and refers to the fact that the rotation states of the multiple blocks 3 are different. The circumferential direction is the direction along the outer circumference of the laminated core 1 or the block 3. The stacking direction is the direction in which the blocks 3 are stacked, and is the direction along the axis (radial center C1) of the laminated core 1. The rotation direction is the rotation direction around the axis of the laminated core 1, and in this embodiment it coincides with the circumferential direction. The radial direction is the direction along the diameter of the laminated core 1.

[0024] Block 3 refers to the smallest unit to be rolled, and can be a single core piece 5 or a laminate of multiple core pieces 5. In this embodiment, Block 3 consists of a laminate of multiple core pieces 5. Specifically, Block 3 is made up of multiple core pieces 5 stacked in the same phase and has the same height in the stacking direction.

[0025] Block 3 may have different heights. Also, if block 3 is a laminate of iron core pieces 5 as in this embodiment, a laminate of multiple divided parts may be formed as a single block 3 by laminating them in the same phase.

[0026] Each core piece 5 is a plate-like body punched out from an electrical steel sheet (not shown). Because the thickness of the electrical steel sheet is not perfectly uniform and has variations (thickness deviation), the core pieces 5 also have thickness deviations. Accordingly, block 3 exhibits eccentricity in the radial direction due to the displacement of the centroids G1 to G6 relative to the center C1, as shown in Figures 2 to 4.

[0027] The eccentricity distance, which is the radial distance between the center of gravity G1-G6 and the center C1 of block 3, is the same for all blocks 3. In Figures 2-4, the eccentricity distance of the center of gravity G1-G6 is indicated by arrows radially relative to the center C1. In addition, the centrifugal forces f1-f3 are also shown by the arrows in Figures 2-4 for convenience, as these are proportional to the eccentricity distance. It is possible to make the eccentricity distances of block 3 different.

[0028] The eccentricity direction of the centroids G1 to G6 of block 3 is shifted according to the phase of block 3 on both sides with respect to the center C2 in the stacking direction. The eccentricity direction is along the straight line connecting the radial center C1 of block 3 to the centroids G1 to G6, respectively.

[0029] The phase of block 3 is shifted relative to adjacent block 3 by an angle of 120 degrees (less than 180 degrees) on both sides of the stacking center C2. Blocks 3 adjacent to each other across the stacking center C2 are in the same phase.

[0030] Depending on the phase of these blocks 3, the centroids G1 to G6 of block 3 are positioned at different phases of 120 degrees each, on both sides of the stacking center C2, which is a predetermined angle. The phase of the centroids G1 to G6 is the circumferential position of the centroids G1 to G6 within block 3.

[0031] In this embodiment, the centroids G1 and G6; G2 and G5; G3 and G4 of blocks 3 that are at the same distance from the center C2 in the stacking direction are eccentric in the same direction with respect to the center C1 in the radial direction. Note that the centroids G1 to G6 of blocks 3 do not need to be positioned at predetermined angles. If the eccentricity distance differs for each block 3, the angle setting should be adjusted according to the eccentricity distance. For example, if the eccentricity distances of the centroids G1 to G6 of blocks 3 differ on one side and the other side with respect to the center C2 in the stacking direction, the phase of the centroids G1 to G6 of blocks 3 will be non-uniform accordingly.

[0032] The predetermined angle in this embodiment can be defined as θ = (360 ÷ N / 2) × m. In this formula, N is the number of stacked blocks 3, and m is any integer greater than or equal to 1. The predetermined angle θ is less than 180 degrees to correspond to the phase difference of the blocks 3. In this embodiment, N is 6 and m is 1, so the predetermined angle θ is 120 degrees as described above.

[0033] m can be set arbitrarily as long as the predetermined angle θ is less than 180 degrees. When m is 1, the eccentricity directions of block 3 do not overlap in the stacking direction on both sides with respect to the stacking center C2. When m is 2 or more, the eccentricity directions of block 3 overlap by the number of m in the stacking direction on both sides with respect to the stacking center C2. Therefore, the centroids of block 3 may be in the same phase with respect to the stacking center C2 on both sides, and it is sufficient that at least some of the phases are different.

[0034] In the laminated core 1 with this configuration, the phase difference angle (a predetermined angle θ) of the multiple blocks 3 is set according to the eccentricity distance of the centroids G1 to G6 of the multiple blocks 3 with respect to the radial center C1 and the arrangement distance with respect to the center C2 in the stacking direction. This adjusts the rotational imbalance in the laminated core 1 caused by the eccentricity of the multiple blocks 3.

[0035] The imbalances being adjusted are imbalances in the stacking direction and imbalances in the rotational direction.

[0036] The unbalance adjustment is performed so that when the laminated core 1 rotates, the force caused by the eccentricity of block 3 is either not generated or reduced. Therefore, the state after unbalance adjustment includes not only cases where rotational balance is perfectly maintained, but also cases where there is rotational imbalance within tolerances or within a range that does not affect the rotation of the laminated core 1. Such unbalance adjustment only needs to be performed on the entire laminated core 1.

[0037] In adjusting the imbalance in the stacking direction in this embodiment, the moments on both sides with respect to the center C2 in the stacking direction due to the centrifugal forces f1 to f3 based on the eccentricity of block 3 are balanced, and the centrifugal forces f1 to f3 on both sides with respect to the radial center C1 of block 3 are balanced.

[0038] In this embodiment, the centroids G1 to G6 of block 3 are arranged at 120-degree intervals in the circumferential direction on both sides of the center C2 in the stacking direction of the laminated core 1, and the centroids G1 and G6, G2 and G5, and G3 and G4, which are at the same distance from the center C2 in the stacking direction, have the same eccentricity distance and eccentricity direction.

[0039] As a result, in the state shown in Figure 1, the centroids G3 and G4 of adjacent blocks 3, separated by the stacking center C2, are located on one side in the radial direction (upper part of Figure 1), while the centroids G1, G2, G5, and G6 of blocks 3 located further out in the stacking direction than these blocks 3 are located on the other side in the radial direction (lower part of Figure 1).

[0040] Furthermore, the radial direction, which coincides with the vertical direction in Figure 1, coincides with the eccentric direction of the centroids G3 and G4 of adjacent blocks 3, with the center C2 in the stacking direction in between. The centroids G1, G2, G5, and G6 of blocks 3 located further out in the stacking direction are inclined at 120 degrees with respect to the radial direction, which coincides with the vertical direction in Figures 2 to 4. Due to this inclination, on the side view in Figure 1, the centrifugal forces f2 and f3 of the outer blocks 3 are half the magnitude of the centrifugal force f1 of the block 3 adjacent to the center C2.

[0041] Therefore, in the laminated core 1, the centrifugal forces f1 to f3 on both sides of the radial center C1 of block 3 are balanced (f1 × 2 = (f2 + f3) × 2). Furthermore, since the centers of gravity G1 and G6; G2 and G5; G3 and G4 of block 3, which are arranged at the same distance from the center C2 in the lamination direction, have the same eccentric direction and eccentric distance, the moments around the center C2 in the lamination direction are balanced. These equilibrium states hold true in all radial directions of the laminated core 1.

[0042] Note that the eccentricity distances of the centers of gravity G1 and G6; G2 and G5; and G3 and G4 in the same eccentricity direction may be different. If the eccentricity distances of the centers of gravity in the same eccentricity direction are different, a moment will be generated around the center C2 in the stacking direction, but this can be canceled out by the moment around center C2 caused by the centers of gravity in other eccentric directions.

[0043] In this embodiment, the adjustment of the rotational imbalance balances the centrifugal forces f1 to f3 based on the eccentricity of block 3 with respect to the radial center C1. That is, as shown in Figures 3 and 4, the centers of gravity G1 to G6 of block 3 are arranged at 120-degree intervals in the circumferential direction, so the centers of gravity G1 to G6 of the six blocks 3 and the resulting centrifugal forces f1 to f3 are evenly distributed in three directions and are in balance.

[0044] Furthermore, in this embodiment, since the blocks 3 are rolled every 120 degrees, the anisotropy of the magnetic properties of the laminated core 1 can be eliminated or reduced. Similar to the magnetic properties, the blocks 3 also exhibit anisotropy in mechanical properties such as bending stiffness in two orthogonal directions passing through the center. In this embodiment, because the blocks 3 are rolled every 120 degrees, the anisotropy of the mechanical properties of the blocks 3 can also be dispersed.

[0045] [Manufacturing method for laminated iron cores] In the manufacturing method of the laminated iron core 1 shown in Figure 1, a transfer is performed in which blocks 3 are stacked on one side with respect to the center C2 in the stacking direction, shifting the phase in one direction (for example, clockwise). Specifically, the next block 3 is rotated by a predetermined angle (120 degrees) in one direction relative to the previous block 3 before being stacked. Alternatively, the previous block 3 may be rotated by a predetermined angle, and the next block 3 may be stacked on top of it without rotation.

[0046] After the three blocks 3 on one side with respect to the center C2 in the stacking direction have been completed, the blocks 3 on the other side with respect to the center C2 in the stacking direction are then stacked. That is, the blocks 3 on the other side are first stacked in the same phase as the adjacent blocks 3 on the one side with respect to the center C2 in the stacking direction.

[0047] Furthermore, subsequent blocks 3 are stacked while shifting their phase in the opposite direction (for example, counterclockwise). In this embodiment, the next block 3 is rotated by a predetermined angle (120 degrees) in the opposite direction to the previous block 3 before being stacked, but the previous block 3 may be rotated by the predetermined angle before stacking the next block 3 on top of it.

[0048] In this way, three blocks 3 are rolled and stacked on each side of the center C2 in the stacking direction. Alternatively, it is possible to form core sections by rolling the blocks 3 on both sides of the center C2 in the stacking direction separately beforehand, and then stack these core sections. In this case, the core section is formed by rolling and stacking the blocks 3 in the opposite direction of rotation. When joining these core sections, the adjacent blocks 3 on either side of the center C2 in the stacking direction are made to be in phase.

[0049] Therefore, the laminated iron core 1 of this embodiment can be manufactured easily and reliably.

[0050] As described above, the laminated core 1 of this embodiment comprises a plurality of blocks 3 stacked with a phase shift of less than 180 degrees. The angles of the plurality of blocks 3 are set according to the eccentricity distance of the centroids G1 to G6 of the plurality of blocks 3 with respect to the radial center C1 and the arrangement distance with respect to the center C2 in the stacking direction, thereby adjusting the rotational imbalance caused by the eccentricity of the plurality of blocks 3.

[0051] Therefore, the laminated core 1 of this embodiment can reliably adjust the rotational imbalance caused by the eccentricity of multiple blocks 3 while keeping the phase difference between blocks 3 to less than 180 degrees, thereby suppressing the generation of vibrations when the laminated core rotates.

[0052] Furthermore, since the phase difference between the blocks 3 is less than 180 degrees, the anisotropy of the magnetic and mechanical properties of block 3 is dispersed, which reliably suppresses the generation of vibrations when the laminated core 1 rotates.

[0053] As a result, the maximum rotational speed of the laminated core 1 can be improved. Furthermore, the laminated core 1 of this embodiment does not require separate balance adjustment, thus reducing the manufacturing process.

[0054] In this embodiment, the number of blocks 3 is six or more, and the centroids G1 and G6; G2 and G5; G3 and G4 of blocks 3 that are at the same distance from the center C2 in the stacking direction are eccentric in the same direction with respect to the center C1 in the radial direction, and the centroids G1 to G6 of blocks 3 are arranged in different phases on one side and the other side with respect to the center C2 in the stacking direction.

[0055] Therefore, in this embodiment, rotational imbalance can be adjusted more reliably, and the generation of vibrations during the rotation of the laminated iron core can be suppressed more reliably.

[0056] Furthermore, in this embodiment, the eccentricity distances of the multiple blocks 3 are the same, and the centroids G1 to G6 of the blocks 3 are arranged at predetermined angle intervals in the circumferential direction on both sides of the stacking center C2.

[0057] Therefore, in this embodiment, rotational imbalance can be adjusted more reliably, and the generation of vibrations during the rotation of the laminated iron core can be suppressed more reliably.

[0058] The predetermined angle is less than 180 degrees and can be defined as θ = (360 ÷ N / 2) × m, where N is the number of stacked blocks 3 and m is any integer greater than or equal to 1.

[0059] Therefore, in this embodiment, rotational imbalance can be adjusted more reliably, and the generation of vibrations during the rotation of the laminated iron core can be suppressed more reliably.

[0060] The manufacturing method for the laminated iron core 1 involves stacking blocks 3 on one side with respect to the center C2 in the stacking direction, shifting the phase in one direction, stacking blocks 3 on the other side with respect to the adjacent block 3 on the other side, and then stacking subsequent blocks 3 with the phase shifted in the opposite direction to the one direction.

[0061] Therefore, this manufacturing method makes it possible to easily and reliably manufacture the laminated iron core 1 of this embodiment. [Explanation of Symbols]

[0062] 1 Laminated iron core 3 blocks 5 Iron core pieces C1 center (radial direction) C2 center (stacking direction) G1~G6 Center of Gravity (Block)

Claims

1. It comprises multiple blocks stacked with a phase shift of less than 180 degrees, The angles of the plurality of blocks are set according to the eccentricity distance of the center of gravity of the plurality of blocks with respect to the radial center and the arrangement distance with respect to the center in the stacking direction, and the rotational imbalance due to the eccentricity of the plurality of blocks is adjusted. Laminated iron core.

2. A laminated iron core according to claim 1, The number of the aforementioned blocks is six or more. The centers of gravity of blocks that are the same distance from the center in the aforementioned stacking direction are eccentric in the same direction with respect to the center in the aforementioned radial direction, At least a portion of the center of gravity of the block is arranged in a different phase on each side of the center in the stacking direction, Laminated iron core.

3. A laminated iron core according to claim 2, The amount of eccentricity of the aforementioned multiple blocks is the same, On each of the aforementioned one side and the aforementioned other side, the center of gravity of the block is arranged at predetermined angles in the circumferential direction. Laminated iron core.

4. A laminated iron core according to claim 3, The predetermined angle is less than 180 degrees and is defined as θ = (360 ÷ N / 2) × m, where N is the number of the plurality of blocks and m is an integer of 1 or more. Laminated iron core.

5. A laminated iron core according to any one of claims 1 to 4, The aforementioned plurality of blocks have the same height in the stacking direction. Laminated iron core.

6. A laminated iron core according to any one of claims 1 to 4, The blocks are stacked on one side with respect to the center of the stacking direction, with a phase shift in one direction. On the other side of the center in the aforementioned stacking direction, the blocks are stacked with a phase shift in a direction opposite to the aforementioned one direction. The blocks on one side and the blocks on the other side that are adjacent to each other across the center of the stacking direction are in the same phase. Laminated iron core.

7. A method for manufacturing a laminated iron core according to any one of claims 1 to 4, On one side of the center in the stacking direction, blocks are stacked with a phase shift in one direction; on the other side of the center in the stacking direction, blocks with the same phase as the adjacent blocks on the one side, straddling the center in the stacking direction, are stacked, and subsequent blocks are stacked with a phase shift in the opposite direction to the aforementioned one direction. A method for manufacturing laminated iron cores.

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