Laminated core, rotor, and method for manufacturing a laminated core

Abstract

The present invention relates to a laminated core, a rotor, and a method for manufacturing a laminated core. In the laminated core, a plurality of steel plates are laminated and integrally formed. The plurality of steel plates include: a first steel plate disposed on the outermost layer on one end side along a central axis and having a first exposed surface; and a second steel plate disposed on the outermost layer on the other end side along the central axis and having a second exposed surface. The difference between the maximum value and the minimum value of the thickness distribution, that is, the distance between the first exposed surface and the second exposed surface, is 0.25 mm or less.

Description

Technical Field

[0001] The present invention relates to a laminated core, a rotor, and a method for manufacturing a laminated core.

[0002] This application is based on Japanese Patent Application No. 2022-035322 filed in Japan on March 8, 2022, and claims priority, the content of which is incorporated herein by reference. Background Art

[0003] Conventionally, there has been a rotor used as a rotating body in a rotating electric machine (electric motor). For example, the rotor uses a laminated core manufactured by laminating and integrating a plurality of electromagnetic steel sheets by caulking using plastic deformation. Alternatively, the rotor uses a laminated core manufactured by laminating and integrating a plurality of electromagnetic steel sheets by bonding.

[0004] However, according to the demand for high speed of electric vehicles, high output of the rotating electric machine is desired. Since the output is proportional to the rotational speed, high rotation is required.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2005-39963

[0008] Patent Document 2: International Publication No. 2021 / 070795 Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] With the advent of hybrid vehicles and electric vehicles, the high speed of rotating electric machines has advanced, and the deformation of the rotor has become significant. Therefore, a technology for suppressing this is required.

[0011] For example, Patent Document 1 discloses the following technology: by increasing the strength of the steel sheets laminated as a laminated core used for the rotor, the steel sheets are brought into the elastic range when the rotor reaches a high rotational speed range, thereby suppressing deformation. In addition, Patent Document 2 also proposes the following: in the manufacture of the laminated core, caulking is not used but an adhesive is used, and the deformation is suppressed by increasing the strength of the adhesive.

[0012] However, since the laminated core has a laminated structure formed by laminating a plurality of steel sheets, the dimensional deviations of the respective steel sheets are also superimposed, and the dimensional deviation of the laminated core tends to become large. Therefore, there is a limit in suppressing the rotor deformation by increasing the strength of the steel sheets. In addition, although the rotational speed can be increased by these technologies for increasing the core strength, it cannot be said to be sufficient in the current situation where high rotation is developing.

[0013] In view of the problems of the above-mentioned background art, an object of the present invention is to provide a laminated core, a rotor, and a method for manufacturing a laminated core that can be applied to a rotating electric machine with a high rotational speed.

[0014] Means for Solving the Problems

[0015] The gist of the present invention is as described below.

[0016] (1) The laminated core according to one aspect of the present invention is integrally formed by laminating a plurality of steel plates, and the plurality of steel plates include: a first steel plate disposed on the outermost layer on one end side along the central axis and having a first exposed surface; and a second steel plate disposed on the outermost layer on the other end side along the central axis and having a second exposed surface. In the laminated core, the difference between the maximum value and the minimum value of the distribution of the distance, that is, the thickness, between the first exposed surface and the second exposed surface is 0.25 mm or less.

[0017] (2) In the above (1), the steel plate may be a non-oriented electromagnetic steel plate having a yield point of 320 MPa or more.

[0018] (3) In the above (1) or (2), it may have a structure in which the steel plates and the adhesive resin are laminated alternately, and the diameter of the steel plate is 80 mm or more and the plate thickness is 0.35 mm or less.

[0019] (4) In the above (3), the adhesive resin may be an acrylic resin or an epoxy resin.

[0020] (5) In any one of the above (1) to (4), the laminated core may have a slot, and the thickness includes the measured value at a first measurement position between the slots adjacent in the circumferential direction.

[0021] (6) In any one of the above (1) to (5), the laminated core may have a slot, and the thickness includes the measured value at a second measurement position between the central axis and the slot.

[0022] (7) In any one of the above (1) to (6), the laminated core may have a slot, and the thickness includes the measured value at a third measurement position between the slots adjacent in the radial direction perpendicular to the central axis.

[0023] (8) In any one of the above (1) to (7), the laminated core may have a slot, and the thickness includes the measured value at a fourth measurement position between the outer peripheral edge and the slot.

[0024] (9) In any one of the above (1) to (8), it is also possible that the adjacent steel plates are joined to each other via fastening portions formed in each of them, and the thickness includes the measured value at the fifth measurement position between the adjacent fastening portions in the circumferential direction.

[0025] (10) The rotor according to one aspect of the present invention may include the laminated core according to any one of the above (1) to (9), and the amplitude amount in the radial direction perpendicular to the central axis when rotating at 16,000 rpm is 250 μm or less.

[0026] (11) The method for manufacturing a laminated core according to one aspect of the present invention is such that the laminated core is integrally formed by laminating a plurality of steel plates. The plurality of steel plates include: a first steel plate disposed on the outermost layer at one end side along the central axis and having a first exposed surface; and a second steel plate disposed on the outermost layer at the other end side along the central axis and having a second exposed surface. In the method for manufacturing the laminated core, it includes a resin coating step of coating an adhesive resin on the steel plates, a lamination step of overlapping a plurality of the steel plates to form a laminate, and a pressure heating step of pressurizing and heating the laminate. In the pressure heating step, the temperature increase is controlled so that the difference between the maximum value and the minimum value of the distribution of the distance, that is, the thickness, between the first exposed surface and the second exposed surface becomes 0.25 mm or less.

[0027] Effects of the Invention

[0028] According to the present invention, it is possible to provide a laminated core, a rotor, and a method for manufacturing a laminated core that can be applied to a rotating electric machine at a high rotational speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic perspective view of the rotor.

[0030] Figure 2 It is in Figure 1 A schematic cross-sectional view as viewed in the E direction perpendicular to the central axis G.

[0031] Figure 3 It is a plan view of the rotor according to the first embodiment.

[0032] Figure 4 It is a plan view of the rotor according to the second embodiment.

[0033] Figure 5 It is a plan view of the rotor according to the third embodiment.

[0034] Figure 6 It is a table showing the test results for the test specimens. DETAILED DESCRIPTION OF THE INVENTION

[0035] The inventors found that: for a rotor with a laminated core in a state where the shape balance is poor due to dimensional deviation (a skewed state compared to a complete rotating body), in the high rotational speed range, particularly due to the wobble in the radial direction perpendicular to the central axis, a large amplitude is generated and excessive deformation occurs.

[0036] Moreover, the inventors found the following insight: by making the shape balance of the laminated core good (becoming a uniform and regular laminated core), in the high rotational speed range, it is possible to suppress the wobble (amplitude amount) in the radial direction perpendicular to the central axis of the rotor and suppress deformation.

[0037] In addition, the inventors found the insight that the shape balance of the laminated core that affects the wobble of the rotor in the high rotational speed range is suitably represented by the core thickness deviation, and found the upper limit of this core thickness deviation.

[0038] Moreover, the laminated core is integrally formed by laminating a plurality of steel plates. The plurality of steel plates include: a first steel plate disposed on the outermost layer at one end side along the central axis and having a first exposed surface; and a second steel plate disposed on the outermost layer at the other end side along the central axis and having a second exposed surface. The laminated core has a slot. Moreover, the core thickness deviation represented by the difference between the maximum value and the minimum value of the distribution of the thickness, which is the distance between the first exposed surface and the second exposed surface, is preferably 0.25 mm or less.

[0039] Thereby, in the high rotational speed range, it is possible to suppress the wobble (amplitude amount) in the radial direction perpendicular to the central axis of the rotor and suppress deformation. Therefore, it is possible to provide a laminated core, a rotor, and a method for manufacturing a laminated core that can be applied to a rotating electric machine at high rotational speeds.

[0040] Hereinafter, embodiments of the present invention will be described.

[0041] (First Embodiment)

[0042] The laminated core 10 according to the first embodiment will be described.

[0043] Figure 1 It is a schematic perspective view of the rotor 100. Figure 2 It is in Figure 1 A schematic cross-sectional view as viewed in the E direction perpendicular to the central axis G. Figure 3 It is a plan view of the rotor 100 according to the first embodiment. In addition, Figure 3 It is a view as viewed along the central axis G.

[0044] As Figure 3As shown, the laminated core 10 according to the first embodiment is used for the rotor 100. The rotor 100 includes the laminated core 10 and the permanent magnet 20. The rotor 100 is used for a rotating electric machine (electric motor). The rotating electric machine includes the rotor 100 and a stator (not shown) disposed so as to surround the outer periphery of the rotor 100. The rotating electric machine may be an IPM (Interior Permanent Magnet: buried magnet type) motor or an induction motor. The rotor 100 is disposed inside the stator.

[0045] The laminated core 10 has, in a portion including the central axis G, an opening F for fitting an output shaft (not shown) and fixing the output shaft. The laminated core 10 is cylindrical with an opening F at the center.

[0046] The laminated core 10 has a number of poles corresponding to the number of poles of the stator. The laminated core 10 has permanent magnets 20 arranged at equal angles corresponding to the number of poles about the central axis G. The laminated core 10 has a shape that is rotationally symmetric about the central axis G and has a number corresponding to the number of poles.

[0047] As Figure 1 and Figure 2 shown, the laminated core 10 is integrally formed by laminating a plurality of steel plates p in the direction along the central axis G. The plurality of steel plates p include: a first steel plate 11 disposed on the outermost layer on one end side along the central axis G and having a first exposed surface 11a; and a second steel plate 12 disposed on the outermost layer on the other end side (opposite to the first steel plate 11) along the central axis G and having a second exposed surface 12a.

[0048] As Figure 3As shown, the laminated core 10 has a slot S. Additionally, the slot S includes a slit for embedding the permanent magnet 20 and a cavity for controlling the magnetic flux distribution, magnetic properties, etc. Moreover, the core thickness deviation represented by the difference between the maximum value and the minimum value of the distribution of the thickness d, which is the distance between the first exposed surface 11a and the second exposed surface 12a, is 0.25 mm or less. Additionally, the thickness d is the distance in the direction of the central axis G between the first exposed surface 11a and the second exposed surface 12a. Additionally, for the measured value of the thickness d required to obtain the core thickness deviation, as long as it is the measured value at two or more locations, it is preferably three or more locations, and more preferably the number of poles of the rotating electric machine or more. Additionally, the upper limit of the core thickness deviation is preferably 0.10 mm. The lower limit of the core thickness deviation is about 0.02 mm industrially. Thus, the core thickness deviation of the laminated core 10 is set to 0.25 mm or less. Thereby, the shape balance of the laminated core 10 can be made good, and the change in the trajectory formed when the laminated core 10 rotates about the central axis G can be suppressed. Therefore, in the high-speed rotation range, the radial wobbling (amplitude amount) perpendicular to the central axis of the rotor 100 can be suppressed, and deformation can be suppressed. Therefore, the laminated core 10 can be applied to a high-speed rotating electric machine.

[0049] The laminated core 10 has a structure in which a plurality of steel plates p are stacked and laminated in the direction of the central axis G. The plurality of steel plates p constituting the laminated core 10 can have the same shape. That is, each of the plurality of steel plates p constituting the laminated core 10 can have the same shape and the same configured slot S, and appropriately have the same shape and the same configured fastening portion K (refer to Figure 4 ).

[0050] For the steel plate p constituting the laminated core 10, the thinner the plate thickness t of the steel plate p, the better the magnetic properties can be made, and the performance of the rotating electric machine can be improved. On the contrary, when the number of laminated steel plates p increases, the superposition of the manufacturing errors of each steel plate unit becomes larger, and the core thickness deviation of the laminated core 10 decreases. Therefore, the upper limit of the plate thickness t of the steel plate p is 0.35 mm, preferably 0.20 mm. The lower limit of the plate thickness t of the steel plate p is 0.15 mm.

[0051] As Figure 2 shown, the laminated core 10 may also have a structure in which the steel plates p and the adhesive resin r are alternately laminated. Moreover, the steel plate p is preferably 80 mm or more in diameter and 0.35 mm or less in plate thickness (plate thickness t). Thereby, a laminated core 10 with as small a core thickness deviation as possible can be formed, and the deformation of the rotor 100 in the high-speed rotation range can be suppressed.

[0052] The steel plate p is preferably a non-oriented electrical steel sheet having a yield point of 320 MPa or more. Thereby, the deformation of the rotor 100 in the high-speed rotation range can be suppressed, and the iron loss can be suppressed, and the performance of the rotor 100 can be improved.

[0053] The adhesive resin r can be an acrylic resin or an epoxy resin. Thus, throughout the entire manufacturing method of the laminated core 10 including the bonding process of adjacent steel plates p to each other, the laminated core 10 can be integrated while suppressing the expansion and contraction of the adhesive resin r as much as possible.

[0054] When the rotor 100 rotates at 16,000 rpm (revolutions per minute), the amplitude in the radial direction perpendicular to the central axis G is 250 μm or less. Here, the amplitude is the maximum displacement in the radial direction perpendicular to the central axis G of the outer peripheral edge 10E of the laminated core 10 when the rotor 100 rotates. The amplitude can be measured, for example, by a laser displacement meter. In Figure 3 and Figure 4 the amplitude can be the displacement measured at the positions and in the directions shown by the arrows Dx and Dy. The measurement positions of the amplitude are preferably two or more locations, and preferably orthogonal to each other. In this way, the core thickness deviation of the laminated core 10 can be suppressed to a low level, and thus the amplitude of the rotor 100 can be suppressed. Therefore, even in the high-speed range where centrifugal force that may cause contact with the stator is generated, the amplitude of the rotor 100 can be suppressed.

[0055] (Measurement position)

[0056] Next, the positions for measuring the thickness d of the laminated core 10 required to obtain the core thickness deviation will be described. In addition, the thickness d of the laminated core 10 can be a measured value obtained by measuring the length of the laminated core 10 along the central axis G at the measurement positions using a measuring instrument such as a vernier caliper or a laser displacement meter. The measured value of the thickness d at a specified measurement position in the laminated core 10 can also be the arithmetic mean of the measured values obtained by measuring the thickness d at the specified measurement position three or more times. When obtaining the distribution of the thickness d, it is preferable to measure the thickness d at four or more measurement positions at equal angles around the central axis G.

[0057] The number of measurement positions is preferably increased according to the number of slots S that the laminated core 10 has.

[0058] As Figure 3 shown, the thickness d of the laminated core 10, that is, the distance between the first exposed surface 11a and the second exposed surface 12a (the surface on the side opposite to the first exposed surface 11a), can also include the measured value at the first measurement position C1 between two slots S (hereinafter, also referred to as slot S1) adjacent to each other in the circumferential direction. Each slot S1 extends in the radial direction and is arranged at intervals from each other in the circumferential direction.

[0059] The first measurement position C1 is not limited as long as it is between the two slots S1. The first measurement position C1 only needs to be within the region surrounded by the two slots S1, the line connecting the radially outer ends of the two slots S1, and the line connecting the radially inner ends of the two slots S1. The first measurement position C1 is preferably the intersection of the line connecting the radially inner end of one of the two slots S1 and the radially outer end of the other slot S1, and the line connecting the radially outer end of the said one slot S1 and the radially inner end of the said other slot S1. When an external force is applied to the laminated core 10 at this intersection, the laminated core 10 is prone to torsion, so it is preferably used as the first measurement position C1.

[0060] In addition, multiple first measurement positions C1 can exist at equal intervals on the same circumference. Thus, during the manufacturing process of the laminated core 10, including the slot forming process of punching the slots S in the steel plate p, the pressurizing and heating processes before and after laminating multiple steel plates p, etc., the thickness d at the first measurement position C1, which is a part that is relatively easy to deform, is measured. Moreover, the core thickness deviation is obtained based on the measured value of the thickness d at the first measurement position C1. Thereby, a uniform and neat laminated core 10 with a low core thickness deviation can be obtained. Therefore, in the high-speed rotation range, the radial runout (amplitude amount) perpendicular to the central axis of the rotor can be suppressed, and deformation can be suppressed.

[0061] In addition, as Figure 3 shown, the thickness d of the laminated core 10 can also include the measured value at the second measurement position C2 between the central axis G and the slot S (hereinafter, also referred to as slot S2). The second measurement position C2 is not limited as long as it is between the central axis G and the slot S2. The second measurement position C2 only needs to be within the region surrounded by the slot S2, the line connecting the front-end side in the rotation direction of the rotor 100 of the circumferential end of the slot S2 and the central axis G, and the line connecting the rear-end side in the rotation direction of the rotor 100 and the central axis G. The second measurement position C2 is preferably the center of the line connecting the intersection of this line and the inner peripheral edge 10F of the laminated core 10 and the intersection of this line and the radially inner side of the slot S2 on the line connecting the central axis G and the center of the slot S2.

[0062] In addition, multiple second measurement positions C2 can exist at equal intervals on the same circumference. Thus, similar to the first measurement position C1, the thickness d at the second measurement position C2, which is a part that is relatively easy to deform, is measured. Moreover, the core thickness deviation is obtained based on the measured value of the thickness d at the second measurement position C2. Thereby, a uniform and neat laminated core 10 with a low core thickness deviation can be obtained. Therefore, in the high-speed rotation range, the radial runout (amplitude amount) perpendicular to the central axis of the rotor can be suppressed, and deformation can be suppressed.

[0063] In addition, as Figure 3 shown, the thickness d of the laminated core 10 may also include the measured value at the third measurement position C3 between two slots S (hereinafter, also referred to as slot S3) adjacent in the radial direction perpendicular to the central axis G. The third measurement position C3 is not limited as long as it is between the two slots S3. The third measurement position C3 only needs to be within the region surrounded by the two slots S3, the line connecting the front-end sides in the rotation direction of the rotor 100 of the circumferential ends of the two slots S3, and the line connecting the rear-end sides in the rotation direction of the rotor 100 of the circumferential ends of the two slots S3.

[0064] The third measurement position C3 is preferably the midpoint of the line connecting the circumferential centers of the two slots S3.

[0065] In addition, multiple third measurement positions C3 may exist at equal intervals on the same circumference. Thus, similar to the first measurement position C1 and the second measurement position C2, the thickness d at the third measurement position C3, which is a portion that is relatively easy to deform, is measured. Moreover, the core thickness deviation is obtained based on the measured value of the thickness d at the third measurement position C3. As a result, a uniform and regular laminated core 10 with a low core thickness deviation can be obtained. Therefore, in the high rotational speed range, the wobbling (amplitude amount) in the radial direction perpendicular to the central axis of the rotor can be suppressed, and deformation can be suppressed.

[0066] The straightness (perpendicularity) of the laminated core 10 is preferably 0.4 or less, and more preferably 0.2 or less. The straightness referred to here means the magnitude of the deviation from the geometrically accurate straight line of the linear shape as defined by "JIS B 0621 - 1984 Definition and Representation of Geometric Deviations" of the Japanese Industrial Standards.

[0067] (Second Embodiment)

[0068] Next, the laminated core 10 according to the second embodiment will be described. In the second embodiment, the description of the parts common to the first embodiment may sometimes be omitted. In the second embodiment, the same reference signs as those attached to the functional parts of the first embodiment are attached to the functional parts common to the first embodiment.

[0069] Figure 4 is a plan view of the rotor 100 according to the second embodiment. In addition, Figure 4 is a view observed along the central axis G.

[0070] The laminated core 10 according to the second embodiment is used for the rotor 100 in the same manner as in the first embodiment. The main differences between the laminated core 10 according to the second embodiment and the first embodiment are the arrangement of the permanent magnets 20 and the fact that the adjacent steel plates p are joined to each other via the fastening portions K.

[0071] As Figure 4 shown, two adjacent steel plates p forming the laminated core 10 are joined to each other via fastening portions K formed in respective ones thereof. Further, the fastening portion K is a portion where opposing portions of adjacent steel plates p are plastically deformed to be press-fitted and joined to each other. Thus, even in the case of the laminated core 10 integrated by the fastening portion K, a uniform and neat laminated core 10 with a low core thickness deviation can be obtained.

[0072] (Measurement position)

[0073] Next, the positions for measuring the thickness d of the laminated core 10 required for obtaining the core thickness deviation will be described.

[0074] As Figure 4 shown, the thickness d of the laminated core 10, that is, the distance between the first exposed surface 11a and the second exposed surface 12a (the surface on the side opposite to the first exposed surface 11a), may also include the measured value at the fourth measurement position C4 between the outer peripheral edge 10E of the laminated core 10 and the slots S (hereinafter, also referred to as slots S4a, S4b).

[0075] The slot S4a extends so as to gradually face the first side (one side) in the circumferential direction as it faces the outer side in the radial direction. The slot S4b is arranged to be adjacent to the slot S4a on the second side (the other side) in the circumferential direction opposite to the first side. The slot S4b extends so as to gradually face the second side in the circumferential direction as it faces the outer side in the radial direction.

[0076] The fourth measurement position C4 is not limited as long as it is between the outer peripheral edge 10E and the slot S4a, and between the outer peripheral edge 10E and the slot S4b. The fourth measurement position C4 is preferably the center between the end on the slot S4b side of the slot S4a and the end on the slot S4a side of the slot S4b, and the center between the portion of the outer peripheral edge 10E located at a position facing the outer side in the radial direction from this center.

[0077] Further, a plurality of fourth measurement positions C4 may be present at equal intervals on the same circumference. Thus, similar to the first measurement position C1 to the third measurement position C3, the thickness d at the fourth measurement position C4 of a portion that is relatively easily deformed is measured. And the core thickness deviation is obtained based on the measured value of the thickness d at the fourth measurement position C4. Thereby, a uniform and neat laminated core 10 with a low core thickness deviation can be obtained. Therefore, in the high rotational speed range, the radial wobble (amplitude amount) perpendicular to the central axis of the rotor can be suppressed, and deformation can be suppressed.

[0078] Further, as Figure 4As shown, the thickness d of the laminated core 10 may also include the measured value at the fifth measurement position C5 between two fastening portions K (hereinafter, also referred to as fastening portion K1) adjacent to each other in the circumferential direction. The fifth measurement position C5 is not limited as long as it is between the circumferences of the two fastening portions K1. The fifth measurement position C5 is preferably the midpoint of the circumferences of the two fastening portions K1.

[0079] In addition, multiple fifth measurement positions C5 may exist at equal intervals on the same circumference. Thus, similar to the first measurement position C1 to the fourth measurement position C4, the thickness d at the fifth measurement position C5 of the portion that is relatively easy to deform is measured. Moreover, the core thickness deviation is obtained based on the measured value of the thickness d at the fifth measurement position C5. As a result, a uniform and neat laminated core 10 with a low core thickness deviation can be obtained. Therefore, in the high rotational speed range, the wobbling (amplitude amount) in the radial direction perpendicular to the central axis of the rotor can be suppressed, and deformation can be suppressed.

[0080] In addition, the thickness d of the laminated core 10 may be measured at multiple measurement positions obtained by appropriately combining the above-mentioned first measurement position C1 to fifth measurement position C5.

[0081] (Third Embodiment)

[0082] Next, the laminated core 10 according to the third embodiment will be described. In the third embodiment, the description of the parts common to the first embodiment or the second embodiment may sometimes be omitted. In the third embodiment, the same reference numerals as those added to the functional parts of the first embodiment or the second embodiment are added to the functional parts common to the first embodiment or the second embodiment.

[0083] Figure 5 is a plan view of the rotor 100 according to the third embodiment. In addition, Figure 5 is a view observed along the central axis G.

[0084] The laminated core 10 according to the third embodiment is used for the rotor 100 of an induction motor. As Figure 5 shown, the rotor 100 is housed inside a hollow cylindrical stator 200 including a stator core wound with coils.

[0085] The rotor 100 has slots S that extend along the central axis G and are cut from the outer peripheral edge 10E toward the central axis G. The slots S have a wedge-shaped cross section perpendicular to the central axis G. A plurality of slots S are arranged at equal intervals in the circumferential direction with the central axis G as the center. Conductors made of materials such as aluminum and copper, which are conductive non-magnetic bodies, are embedded in the slots S.

[0086] (Measurement Position)

[0087] Next, the positions for measuring the thickness d of the laminated core 10 required to obtain the core thickness deviation will be described.

[0088] As Figure 5 shown, the thickness d of the laminated core 10, that is, the distance between the first exposed surface 11a and the second exposed surface 12a (the surface on the side opposite to the first exposed surface 11a), may also include the measured value at the first measurement position C1 between two adjacent slots S in the circumferential direction. In addition, multiple first measurement positions C1 may be equally spaced on the same circumference (for example, there are 4 positions in the configuration shown in Figure 5 ). In this way, during the manufacturing process of the laminated core 10, the thickness d at the first measurement position C1 of the part that is relatively easy to deform is measured. Moreover, the core thickness deviation is obtained based on the measured value of the thickness d at the first measurement position C1. Thereby, a uniform and regular laminated core 10 with a low core thickness deviation can be obtained. Therefore, in the high-speed rotation range, the radial wobbling (amplitude amount) perpendicular to the central axis of the rotor can be suppressed, and deformation can be suppressed.

[0089] In addition, as Figure 5 shown, the thickness d of the laminated core 10 may also include the measured value at the second measurement position C2 between the central axis G and the slot S. In addition, multiple second measurement positions C2 may be equally spaced on the same circumference (for example, there are 4 positions in the configuration shown in Figure 5 ). In this way, similar to the first measurement position C1, the thickness d at the second measurement position C2 of the part that is relatively easy to deform is measured. Moreover, the core thickness deviation is obtained based on the measured value of the thickness d at the second measurement position C2. Thereby, a uniform and regular laminated core 10 with a low core thickness deviation can be obtained. Therefore, in the high-speed rotation range, the radial wobbling (amplitude amount) perpendicular to the central axis of the rotor can be suppressed, and deformation can be suppressed.

[0090] (Manufacturing Method)

[0091] Next, the manufacturing method of the laminated core 10 will be described.

[0092] The laminated core 10 is integrally formed by laminating multiple steel plates in the direction along the central axis G. The multiple steel plates include a first steel plate 11 disposed on the outermost layer at one end side along the central axis G and having a first exposed surface 11a, and a second steel plate 12 disposed on the outermost layer at the other end side along the central axis G and having a second exposed surface 12a.

[0093] Adjacent steel plates p can be joined via an adhesive resin r, can be joined via a fastening portion K, or can be joined via both the adhesive resin r and the fastening portion K.

[0094] Specifically, an adhesive resin r is applied to the steel plate p (resin application process).

[0095] A slot S is formed in the steel plate p (slot formation process).

[0096] Multiple steel plates p are overlapped to form a laminate (lamination process).

[0097] Moreover, the laminate obtained through the lamination process is pressurized and heated (pressurizing and heating process). Thereby, the bonding strength between adjacent steel plates p is promoted. In this pressurizing and heating process, the heating temperature is controlled so that the core thickness deviation represented by the difference between the maximum value and the minimum value of the distribution of the thickness d, which is the distance between the first exposed surface 11a and the second exposed surface 12a, becomes 0.25 mm or less.

[0098] After the pressurizing and heating process, the laminate is cooled (cooling process).

[0099] When the cooling process ends, all the processes of the manufacturing method of the laminated core 10 end, and the laminated core 10 is manufactured.

[0100] For example, in the pressurizing and heating process, depending on the material of the adhesive resin r, the size and configuration of the slot S, the presence or absence of the fastening portion K, etc., the temperature is raised from the normal temperature (20 degrees) state at a rate of 10 degrees / second or less to 220 degrees so that the core thickness deviation becomes 0.25 mm or less.

[0101] In the case where the laminated core 10 includes multiple steel plates p and multiple adhesive resins r, the surface area of the multiple steel plates p is larger than the surface area of the multiple adhesive resins r. Therefore, compared with the temperature deviation of the multiple adhesive resins r, the core thickness deviation is dominated by the temperature deviation of the multiple steel plates p. Thus, even when the slot S is provided on the steel plate p and the adjacent steel plates p are laminated by being joined to each other through the adhesive resin r or the fastening portion K, the core thickness deviation of the laminated core 10 can be suppressed to a low level.

[0102] In the pressurizing and heating process, when the laminate is pressurized in a mold, the laminate can be pressurized from the side (radial direction). Therefore, for example, the pressurizing pressure can be suppressed to about 0.5 MPa (megapascal). On the other hand, when the laminate is pressurized outside the mold, the laminate cannot be pressurized from the side. Therefore, for example, the pressurizing pressure needs to be set to about 1.0 MPa.

[0103] In the cooling process, for example, it is preferable to cool the laminate by air cooling or the like at a rate of 10 degrees / second or less.

[0104] (Test)

[0105] Next, a test was conducted to measure the amount of amplitude (runout) of the rotor 100 with the laminated core 10 when rotating in a high rotational speed range of 16,000 rpm. Figure 6 It is a table showing the test results.

[0106] For several test bodies (Examples 1 - 12 and Comparative Examples 1 - 3) of the rotor 100 with combinations of various conditions such as the motor type, the joining structure of the laminated core 10 (joining via the adhesive resin r or joining via the fastening portion K), the type of the steel plate p (combination of tensile strength, yield point, elongation, and hardness Hv), the core thickness deviation of the laminated core 10 (rotor 100), the type of the adhesive resin r, the diameter of the steel plate p, and the plate thickness t of the steel plate p, tests were conducted.

[0107] The steel grades of the steel plates p constituting the laminated core 10 used for the test bodies are shown in Table 1. Electrical steel sheets were used as the steel plates p. In addition, in Table 1, YP represents the yield point strength in MPa. W15 / 50 is the upper limit of the loss per unit weight with a magnetic flux density amplitude of 1.5 T (tesla) or more and a frequency of 50 Hz, expressed in W / kg. W10 / 400 is the upper limit of the loss per unit weight with a magnetic flux density amplitude of 10 T or more and a frequency of 400 Hz, expressed in W / kg.

[0108]

Table 1

[0109] Steel grade YP W15 / 50 W1 O / 400 25HX1 300 394 2.02 12.4 27HX1500 385 2.06 13.7 30HX1800 371 14.7 20HTH1 200 419 10.8 35H210 391 2.01 25HX1 400 394 13.3 25CS1 250HF 410 2.01 12.2

[0110] The thickness d of the rotor that became the test body was set to 150 mm ± 0.5%.

[0111] When the laminated core used for the rotor that became the test body has a joining structure via the adhesive resin r, it is manufactured as follows: The steel plate p coated with the adhesive resin r is blanked by stamping to form a plurality of steel plate elements, and the laminate formed by laminating the plurality of steel plate elements is pressurized and heated. The core thickness deviation is affected by the heating rate (when the heating rate is too low, the adhesive resin r drops unevenly and the flatness decreases. When the heating rate is too high, the steel plate p deforms and the flatness decreases). Therefore, in order to obtain the desired flatness, the test bodies were produced by adjusting the heating rate.

[0112] In addition, when the laminated core used for the rotor that became the test body has a joining structure via the fastening portion K, it is manufactured as follows: A plurality of steel plate elements are formed, and the plurality of steel plate elements are laminated so that adjacent steel plate elements are caulked with each other and integrally formed. Then, the core thickness deviation was measured. Since extremely minute deformation of the steel plate p is reflected in the core thickness deviation, in order to obtain the desired flatness, the test bodies were produced by finely adjusting the shape dimensions of the stamping die, the pressure amount, etc.

[0113] The thickness d of the laminated core 10 for obtaining the flatness was measured at all the measurement positions of the first measurement position C1 (8 positions), the second measurement position C2 (8 positions), and the third measurement position C3 (8 positions) shown below with a vernier caliper. Then, the flatness was obtained as the absolute value of the difference between the minimum value and the maximum value of these measurement values (distribution of the thickness d). Figure 3 As shown below, while rotating the rotor at 16,000 rpm or more, the distance changes in the directions of arrow Dx and arrow Dy were measured with a laser displacement meter, and the maximum value thereof was set as the amplitude amount.

[0114] As Figure 3 shown below, while rotating the rotor at 16,000 rpm or more, the distance changes in the directions of arrow Dx and arrow Dy were measured with a laser displacement meter, and the maximum value thereof was set as the amplitude amount.

[0115] When the amplitude amount is 150 μm or less, it is evaluated as Excellent. When the amplitude amount exceeds 150 μm and is 250 μm or less, it is evaluated as Good. When the amplitude amount exceeds 250 μm, it is evaluated as No Good. Moreover, the test specimens evaluated as Excellent or Good are regarded as qualified.

[0116] Regarding each test specimen and the test results, they are as follows.

[0117] (1) The test specimen that is the rotor of Example 1 is for an IPM motor. The test specimen that is the rotor of Example 1 uses a laminated core having a joining structure in which a plurality of steel plates (25HX1300) with a plate thickness (plate thickness t) of 0.25 mm and a diameter of 166 mm are joined via an epoxy-based adhesive resin. The core thickness deviation of the test specimen that is the rotor of Example 1 is 0.04 mm.

[0118] As a result of the test, the amplitude amount when the test specimen of Example 1 was rotated at 16,000 rpm was 150 μm or less.

[0119] (2) The test specimen that is the rotor of Example 2 is for an IPM motor. The test specimen that is the rotor of Example 2 uses a laminated core having a joining structure in which a plurality of steel plates (30HX1800) with a plate thickness (plate thickness t) of 0.30 mm and a diameter of 133 mm are joined via a fastening portion K. The core thickness deviation of the test specimen that is the rotor of Example 2 is 0.20 mm.

[0120] As a result of the test, the amplitude amount when the test specimen of Example 2 was rotated at 16,000 rpm was 150 μm or less.

[0121] (3) The test body of the rotor of Example 3 is for an induction motor. The test body of the rotor of Example 3 uses a laminated core with a bonding structure in which a plurality of steel plates (25HX1300) with a plate thickness (plate thickness t) of 0.25 mm and a diameter of 166 mm are joined via an epoxy-based adhesive resin. The core thickness deviation of the test body of the rotor of Example 3 is 0.06 mm.

[0122] As a result of the test, the amplitude amount when the test body of Example 3 rotates at 16000 rpm is 150 μm or less.

[0123] (4) The test body of the rotor of Example 4 is for an IPM motor. The test body of the rotor of Example 4 uses a laminated core with a bonding structure in which a plurality of steel plates (20HTH1200) with a plate thickness (plate thickness t) of 0.20 mm and a diameter of 160 mm are joined via an epoxy-based adhesive resin. The core thickness deviation of the test body of the rotor of Example 4 is 0.25 mm.

[0124] As a result of the test, the amplitude amount when the test body of Example 4 rotates at 16000 rpm exceeds 150 μm and is 250 μm or less.

[0125] (5) The test body of the rotor of Example 5 is for an IPM motor. The test body of the rotor of Example 5 uses a laminated core with a bonding structure in which a plurality of steel plates (35H210) with a plate thickness (plate thickness t) of 0.35 mm and a diameter of 133 mm are joined via a fastening part K. The core thickness deviation of the test body of the rotor of Example 5 is 0.25 mm.

[0126] As a result of the test, the amplitude amount when the test body of Example 5 rotates at 16000 rpm exceeds 150 μm and is 250 μm or less.

[0127] (6) The test body of the rotor of Example 6 is for an induction motor. The test body of the rotor of Example 6 uses a laminated core with a bonding structure in which a plurality of steel plates (27HX1500) with a plate thickness (plate thickness t) of 0.27 mm and a diameter of 163 mm are joined via an epoxy-based adhesive resin. The core thickness deviation of the test body of the rotor of Example 6 is 0.25 mm.

[0128] As a result of the test, the amplitude amount when the test body of Example 6 rotates at 16000 rpm exceeds 150 μm and is 250 μm or less.

[0129] (7) The test body of the rotor of Example 7 is for an IPM motor. The test body of the rotor of Example 7 uses a laminated core with a joint structure in which a plurality of steel plates (25HX1300) with a plate thickness (plate thickness t) of 0.25 mm and a diameter of 300 mm are joined via an epoxy-based adhesive resin. The core thickness deviation of the test body of the rotor of Example 7 is 0.08 mm.

[0130] As a result of the test, the amplitude amount when the test body of Example 7 rotates at 16,000 rpm is 150 μm or less.

[0131] (8) The test body of the rotor of Example 8 is for an IPM motor. The test body of the rotor of Example 8 uses a laminated core with a joint structure in which a plurality of steel plates (27HX1500) with a plate thickness (plate thickness t) of 0.27 mm and a diameter of 330 mm are joined via an epoxy-based adhesive resin. The core thickness deviation of the test body of the rotor of Example 8 is 0.14 mm.

[0132] As a result of the test, the amplitude amount when the test body of Example 8 rotates at 16,000 rpm exceeds 150 μm and is 250 μm or less.

[0133] (9) The test body of the rotor of Example 9 is for an IPM motor. The test body of the rotor of Example 9 uses a laminated core with a joint structure in which a plurality of steel plates (25HX1300) with a plate thickness (plate thickness t) of 0.15 mm and a diameter of 133 mm, which are cold-rolled, are joined via an epoxy-based adhesive resin. The core thickness deviation of the test body of the rotor of Example 9 is 0.25 mm.

[0134] As a result of the test, the amplitude amount when the test body of Example 9 rotates at 16,000 rpm exceeds 150 μm and is 250 μm or less.

[0135] (10) The test body of the rotor of Example 10 is for an IPM motor. The test body of the rotor of Example 10 uses a laminated core with a joint structure in which a plurality of steel plates (25HX1300) with a plate thickness (plate thickness t) of 0.12 mm and a diameter of 133 mm, which are cold-rolled, are joined via an epoxy-based adhesive resin. The core thickness deviation of the test body of the rotor of Example 10 is 0.25 mm.

[0136] As a result of the test, the amplitude amount when the test body of Example 10 rotates at 16,000 rpm exceeds 150 μm and is 250 μm or less.

[0137] (11) The test body of the rotor of Example 11 is for an IPM motor. The test body of the rotor of Example 11 uses a laminated core with a joining structure in which multiple steel plates (25CS1250) with a plate thickness (plate thickness t) of 0.25 mm and a diameter of 133 mm are joined via an epoxy-based adhesive resin. The core thickness deviation of the test body of the rotor of Example 11 is 0.09 mm.

[0138] As a result of the test, the amplitude amount when the test body of Example 11 rotates at 16000 rpm is 150 μm or less.

[0139] (12) The test body of the rotor of Example 12 is for an IPM motor. The test body of the rotor of Example 12 uses a laminated core with a joining structure in which multiple steel plates (25HX1300) with a plate thickness (plate thickness t) of 0.25 mm and a diameter of 133 mm are joined via an acrylic-based adhesive resin. The core thickness deviation of the test body of the rotor of Example 12 is 0.06 mm.

[0140] As a result of the test, the amplitude amount when the test body of Example 12 rotates at 16000 rpm is 150 μm or less.

[0141] (A) The test body of the rotor of Comparative Example A is for an IPM motor. The test body of the rotor of Comparative Example A uses a laminated core with a joining structure in which multiple steel plates (25HX1300) with a plate thickness (plate thickness t) of 0.25 mm and a diameter of 163 mm are joined via an epoxy-based adhesive resin. The core thickness deviation of the test body of the rotor of Comparative Example A is 0.28 mm.

[0142] As a result of the test, the amplitude amount when the test body of Comparative Example A rotates at 16000 rpm exceeds 250 μm.

[0143] (B) The test body of the rotor of Comparative Example B is for an IPM motor. The test body of the rotor of Comparative Example B uses a laminated core with a joining structure in which multiple steel plates (30HX1800) with a plate thickness (plate thickness t) of 0.30 mm and a diameter of 163 mm are joined via a fastening part K. The core thickness deviation of the test body of the rotor of Comparative Example B is 0.28 mm.

[0144] As a result of the test, the amplitude amount when the test body of Comparative Example B rotates at 16000 rpm exceeds 250 μm.

[0145] (C) The test body of the rotor of Comparative Example C is for an induction motor. The test body of the rotor of Comparative Example C uses a laminated core with a joining structure in which multiple steel plates (25HX1300) with a plate thickness (plate thickness t) of 0.25 mm and a diameter of 163 mm are joined via an epoxy-based adhesive resin. The core thickness deviation of the test body of the rotor of Comparative Example C is 0.28 mm.

[0146] As a result of the test, the amplitude amount when the test body of Comparative Example C rotates at 16,000 rpm exceeds 250 μm.

[0147] As a result of the test, as Figure 6 shown, in the cases where the core thickness deviation becomes 0.25 mm or less, that is, the cases of Examples 1 to 12, the amplitude amount at 16,000 rpm converges to 250 μm or less, resulting in good results. In particular, in the cases of Examples 1-3, 7, 11, and 12, the amplitude amount at 16,000 rpm converges to 150 μm or less, resulting in even better (excellent) results. In contrast to these results, in the cases where the core thickness deviation exceeds 0.25 mm, that is, the cases of Comparative Example A, Comparative Example B, and Comparative Example C, the amplitude amount at 16,000 rpm exceeds 250 μm, resulting in a relatively large amplitude amount (NoGood).

[0148] <Other Embodiments>

[0149] As described above, one embodiment has been described in detail with reference to the accompanying drawings, but the specific configuration is not limited to the above, and various design changes and the like can be made.

[0150] The laminated core 10 according to the present embodiment is integrally formed by laminating a plurality of steel plates p. The plurality of steel plates p include: a first steel plate 11 disposed on the outermost layer on one end side along the central axis G and having a first exposed surface 11a; and a second steel plate 12 disposed on the outermost layer on the other end side along the central axis G and having a second exposed surface 12a. The core thickness deviation represented by the difference between the maximum value and the minimum value of the distribution of the thickness d, which is the distance between the first exposed surface 11a and the second exposed surface 12a, is 0.25 mm or less. In this way, by forming a uniform and neat laminated core 10, the amplitude amount (vibration swing) of the rotor can be suppressed to a small value even in a high rotation speed range. Therefore, even if the laminated steel plates used for the laminated core 10 are not made of high strength, the laminated core 10 that is difficult to deform in a high rotation speed range can be obtained. Thus, a laminated core 10, a rotor 100, and a method for manufacturing the laminated core 10 that can be applied to a rotating electric machine with a high rotation speed can be provided.

[0151] The rotor 100 according to the present embodiment has an amplitude amount in the radial direction perpendicular to the central axis G of 250 μm or less when rotating at 16,000 rpm. Therefore, even in a high rotation speed range where a centrifugal force that may cause contact with the stator is generated, the amplitude amount of the rotor 100 can be suppressed.

[0152] The laminated core 10 may not have the slot S. In this case, the method for manufacturing the laminated core 10 may not include a slot forming process.

[0153] The manufacturing method of the laminated core 10 according to this embodiment is to integrally form by laminating a plurality of steel plates p. The plurality of steel plates p include: a first steel plate 11 disposed on the outermost layer on one end side along the central axis G and having a first exposed surface 11a; and a second steel plate 12 disposed on the outermost layer on the other end side along the central axis G and having a second exposed surface 12a. Moreover, it includes a resin coating process of coating an adhesive resin r on the steel plate p, a lamination process of overlapping a plurality of steel plates p to form a laminate, and a pressure heating process of pressurizing and heating the laminate. Moreover, in the pressure heating process, the temperature increase is controlled so that the difference between the maximum value and the minimum value of the distribution of the distance d, that is, the thickness, between the first exposed surface 11a and the second exposed surface 12a becomes 0.25 mm or less. Thus, even if the steel plates p adjacent to each other through the adhesive resin r or the fastening portion K are joined and laminated to each other, the core thickness deviation of the laminated core 10 can be suppressed to a low level.

[0154] Industrial availability

[0155] The laminated core, the rotor, and the manufacturing method of the laminated core can be applied to high-speed rotating electrical machines. Therefore, the industrial availability is large.

[0156] Explanation of symbols

[0157] 10: Laminated core

[0158] 10E: Outer peripheral edge

[0159] 11: First steel plate

[0160] 11a: First exposed surface

[0161] 12: Second steel plate

[0162] 12a: Second exposed surface

[0163] 20: Permanent magnet

[0164] 100: Rotor

[0165] 200: Stator

[0166] C1: First measurement position

[0167] C2: Second measurement position

[0168] C3: Third measurement position

[0169] C4: Fourth measurement position

[0170] C5: Fifth measurement position

[0171] Dx: Arrow

[0172] Dy: Arrow

[0173] F: Opening

[0174] G: Central axis

[0175] K: Fastening part

[0176] S: Slot

[0177] p: Steel plate

[0178] r: Adhesive resin

[0179] d: Thickness of laminated core

[0180] t: Thickness of steel plate

Claims

1. A laminated core is integrally formed by laminating a plurality of steel plates, and the plurality of steel plates include: A first steel plate disposed on the outermost layer at one end side along the central axis and having a first exposed surface; and a second steel plate disposed on the outermost layer at the other end side along the central axis and having a second exposed surface. In the laminated core, the difference between the maximum value and the minimum value of the distribution of the distance (i.e., thickness) between the first exposed surface and the second exposed surface is 0.25 mm or less.

2. The laminated core according to claim 1, wherein the steel plate is a non-oriented electromagnetic steel plate having a yield point of 320 MPa or more.

3. The laminated core according to claim 1 or 2, wherein it has a structure in which the steel plates and the adhesive resin are alternately laminated, the diameter of the steel plate is 80 mm or more and the plate thickness is 0.35 mm or less.

4. The laminated core according to claim 3, wherein the adhesive resin is an acrylic resin or an epoxy resin.

5. The laminated core according to claim 1 or 2, wherein the laminated core has a slot, the thickness includes the measured value at a first measurement position between the slots adjacent in the circumferential direction.

6. The laminated core according to claim 1 or 2, wherein the laminated core has a slot, the thickness includes the measured value at a second measurement position between the central axis and the slot.

7. The laminated core according to claim 1 or 2, wherein the laminated core has a slot, the thickness includes the measured value at a third measurement position between the slots adjacent in the radial direction perpendicular to the central axis.

8. The laminated core according to claim 1 or 2, wherein the laminated core has a slot, the thickness includes the measured value at a fourth measurement position between the outer peripheral edge and the slot.

9. The laminated core according to claim 1 or 2, wherein adjacent steel plates are joined to each other via fastening portions formed in each of them, the thickness includes the measured value at a fifth measurement position between the fastening portions adjacent in the circumferential direction.

10. A rotor, wherein it includes the laminated core according to claim 1 or 2, the amplitude amount in the radial direction perpendicular to the central axis when rotating at 16,000 rpm is 250 μm or less.

11. A method for manufacturing a laminated core, the laminated core being integrally formed by laminating a plurality of steel plates, the plurality of steel plates including: A first steel plate disposed on the outermost layer at one end side along the central axis and having a first exposed surface; and a second steel plate disposed on the outermost layer at the other end side along the central axis and having a second exposed surface. In the manufacturing method of the laminated core, it includes a resin coating step of coating an adhesive resin on the steel plate, a lamination step of overlapping a plurality of the steel plates to form a laminate, and a pressure heating step of pressurizing and heating the laminate, in the pressure heating step, the temperature increase is controlled so that the difference between the maximum value and the minimum value of the distribution of the distance (i.e., thickness) between the first exposed surface and the second exposed surface becomes 0.25 mm or less.

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