JP2014079068A - Rotor core and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotor core and a method for manufacturing the same, capable of non-magnetizing a bridge by heat treatment while suppressing a short circuit between core sheets laminated in a rotary shaft direction.SOLUTION: A cylindrical rotor core 10 is formed by laminating a plurality of core sheets S1 in a rotary shaft direction, the core sheets each obtained by forming an electromagnetic steel plate into a predetermined shape, the core sheets being arranged so that a plurality of magnet holes S11 provided in the core sheets S1 are communicated with each other in the rotary shaft direction. The core sheet S1 includes an opening A in which an end of the magnet hole S11 is opened in an outer periphery of the core sheet S1, and a bridge B provided between the end of the magnet hole S11 and the outer periphery of the core sheet S1. At least one of the openings A is disposed at a position adjacent to the bridge B in the rotary shaft direction, and the bridge B is non-magnetized by heat treatment.

Description

  The present invention relates to a rotor core used in a radial gap type rotating electrical machine and a method for manufacturing the same.

  A radial gap type rotating electrical machine is a rotating electrical machine that includes a rotor that is arranged to be rotatable about a rotation axis, and a stator that is arranged with a gap in the radial direction of the rotor. As one of such rotating electrical machines, a rotating electrical machine called an interior permanent magnet (IPM) type is known. As shown in FIG. 11, the rotor for the IPM type rotating electrical machine has a large number of core sheets S formed of electromagnetic steel sheets in a predetermined shape in a direction parallel to the axis O of the rotation shaft (hereinafter referred to as the rotation axis direction). A cylindrical rotor core 40 formed by stacking is provided. The rotor core 40 is provided with a plurality of magnet hole portions 41. By embedding a plurality of magnets (not shown) in each magnet hole 41, the rotor core 40 is magnetized, and magnetic poles P having different polarities (N pole, S pole) are alternately formed in the rotation direction on the outer periphery thereof.

  As shown in FIG. 12, the conventional rotor core 40 includes a portion (inner side Si) located on the inner side in the radial direction with respect to each magnet hole S <b> 41 provided in the core sheet S, and a portion located on the outer side (outer portion So). Are connected by a bridge B provided between the end of each magnet hole S41 and the outer periphery of the core sheet S. For this reason, the magnetic flux is short-circuited in the bridge B, and a leakage magnetic flux is generated. Leakage magnetic flux is unfavorable in terms of performance of the rotating electrical machine because it hinders effective utilization of the magnetic characteristics of the magnet and at the same time reduces reluctance torque.

  Therefore, a technique for reducing the leakage magnetic flux generated in the bridge B by demagnetizing the bridge B by a predetermined heat treatment is disclosed in the following patent document. As the predetermined heat treatment, for example, a process of rapidly cooling in water after heating by laser irradiation (see Patent Document 1), a process of performing laser irradiation while supplying a specific metal element, and modifying a magnetic material into a non-magnetic component (patent) Reference 2), and diffusion / penetration treatment (see Patent Document 3) in which a region coated with a coating material containing a nonmagnetic substance is heated.

  However, since these heat treatments need to be performed at a high temperature of, for example, about 800 to 1200 ° C., an insulating film (not shown) formed on the surface of each core sheet S is melted during the heat treatment. As a result, the insulation between the core sheets S adjacent in the rotation axis direction is broken, and a short circuit occurs between the laminations of the core sheets S. Since an eddy current that causes an increase in iron loss of the rotor core 40 is generated between each short-circuited core sheet S, the efficiency improvement of the rotating electrical machine is hindered by the eddy current, and at the same time, leakage due to the non-magnetic bridge B is caused. The actual benefits of reducing magnetic flux are poor.

JP 2010-93972 A JP-A-9-306714 JP 2003-304670 A

  The present invention has been made in view of such circumstances, and a rotor core capable of demagnetizing a bridge by heat treatment while suppressing a short circuit between the core sheets laminated in the rotation axis direction, and the manufacture thereof It aims to provide a method.

  The present invention is a cylinder formed by laminating a plurality of core sheets formed of electromagnetic steel sheets in a predetermined shape in the rotation axis direction, and arranged so that a plurality of magnet holes provided in the core sheet communicate in the rotation axis direction. An opening in which the end of the magnet hole is opened at the outer periphery of the core sheet, and a bridge provided between the end of the magnet hole and the outer periphery of the core sheet, And at least one of the openings is disposed at a position adjacent to the bridge in the rotation axis direction, and the bridge is demagnetized by heat treatment.

  The bridge and the opening are alternately arranged in the rotation axis direction for each of the core sheets.

  The said core sheet WHEREIN: The said bridge | bridging is provided in any one edge part among the both ends of the said magnet hole, and the said opening part is provided in the other edge part, It is characterized by the above-mentioned.

  The core sheet includes a first core sheet in which the bridges are provided at both ends of the magnet holes, and a second core sheet in which the openings are provided at both ends of the magnet holes. To do.

  Said 1st core sheet | seat is arrange | positioned at the both ends of the rotating shaft direction, It is characterized by the above-mentioned.

  A core caulking for fixing a gap between the core sheets is provided on either one or both of the outer side and the inner side in the radial direction from the magnet hole of the core sheet.

  The core sheet is laminated through an adhesive layer.

  The core sheet includes a second bridge provided at a position different from an end of the magnet hole.

  Further, the present invention is formed by laminating a plurality of core sheets formed of electromagnetic steel sheets in a predetermined shape in the rotation axis direction, and arranged so that a plurality of magnet holes provided in the core sheet communicate in the rotation axis direction. A cylindrical rotor core manufacturing method, the process A for preparing the electromagnetic steel sheet, and the process B for punching the electromagnetic steel sheet into a predetermined shape by one or a plurality of molds to form a plurality of the core sheets, A plurality of the core sheets are stacked in the direction of the rotation axis, and an opening in which the end of the magnet hole is opened at the outer periphery of the core sheet, and between the end of the magnet hole and the outer periphery of the core sheet And a step C of forming a cylindrical laminated body in which at least one opening is disposed at a position adjacent to the bridge in the rotation axis direction, and an outer periphery of the laminated body. Corresponds to the bridge of the surface A heat treatment for the partial, characterized in that it comprises a and a step D of nonmagnetic the bridge.

  In the step C, the core sheets are laminated so that the bridges and the openings are alternately arranged in the rotation axis direction for each of the core sheets.

  In the step B, the core sheet is formed in which the bridge is provided at one of the ends of the magnet hole and the opening is provided at the other end.

  In the step B, the core sheet in which the position of the bridge with respect to the magnet hole is the same in each magnetic pole is formed, and in the step C, one side of the core sheet and the other side of each of the core sheets Each of the core sheets is laminated so that they are in contact with each other.

  In the step B, the core sheet in which the position of the bridge with respect to the magnet hole is alternately different for each magnetic pole is formed, and in the step C, the core sheet is relatively relative to the magnetic pole pitch for each one or a plurality of the core sheets. It is characterized by laminating while rotating.

  In the step B, the first core sheet having the bridge provided at both ends of the magnet hole and the second core sheet having the opening provided at both ends of the magnet hole are formed. .

  The heat treatment performed in the step D is a heat treatment by laser irradiation.

  According to the rotor core and the manufacturing method thereof of the present invention, by arranging the opening at a position adjacent to the bridge and the rotation axis direction, the lamination of each core sheet is continuously short-circuited by the heat treatment for each bridge. Can be suppressed. Thereby, the influence by an eddy current is reduced effectively and the iron loss increase of a rotor core can be suppressed. Moreover, since each bridge can be made non-magnetic while suppressing a short circuit between the laminations of each core sheet, generation of leakage magnetic flux in each bridge can be suppressed together with an increase in iron loss of the rotor core. Therefore, as in the prior art, the actual benefit of reducing the leakage magnetic flux by demagnetizing the bridge by heat treatment is not impaired by the influence of eddy currents caused by the short circuit between the core sheets. Therefore, the efficiency of the rotating electrical machine can be greatly improved as compared with the conventional rotor core.

  In addition, if the bridges and openings are alternately arranged in the direction of the rotation axis for each core sheet, each bridge can be made non-magnetic while maintaining insulation between the laminations of all the core sheets. In addition, it is possible to reliably prevent the generation of eddy current due to the short circuit between the core sheets. Thereby, the iron loss of the core can be further reduced, and the efficiency of the rotating electrical machine can be greatly improved.

  If a core sheet having a bridge at one end of the magnet hole and an opening at the other end is used, the rotor core can be formed from the core sheet having the same shape. The cost of equipment such as molds can be reduced. Also, the heat treatment (step D) by laser irradiation may be performed in a straight line in the direction of the rotation axis, so that a particularly precise positioning operation or the like is not required. Therefore, improvement in rotor core production efficiency and reduction in product cost can be realized at the same time.

  Step B of forming a core sheet by using a first core sheet provided with bridges at both ends of each magnet hole and a second core sheet provided with openings at both ends of each magnet hole as the core sheet Since the process C for laminating the core sheets in the direction of the rotation axis can be simplified, the production efficiency of the rotor core can be further improved.

  If the first core sheet is disposed at both ends in the rotation axis direction, the second core sheet can be held between the first core sheets. For this reason, the mechanical strength of the rotor core is increased.

  If a core caulking that fixes the lamination between core sheets is provided on either or both of the outer side and the inner side in the radial direction from the magnet hole of the core sheet, each core sheet is easily positioned by each core caulking. A desired laminate can be formed while sequentially fixing the laminates, and the laminates of the core sheets can be more firmly fixed.

  If each core sheet is laminated through an adhesive layer, as long as the mechanical strength of the rotor core can be sufficiently secured, for example, holes for attaching fixing members such as caulking pins, core caulking, etc. need to be formed in each core sheet. Disappear. Thereby, while preventing the flow of magnetic flux from being inhibited, the magnetic resistance of the rotor core can be reduced.

  If the core sheet provided with the 2nd bridge provided in the position different from the edge part of a magnet hole is used, the mechanical strength of a rotor core can be improved. Thereby, while improving the dimensional accuracy of a finished product, the deformation | transformation of the rotor core during production or use of a rotary electric machine can be suppressed.

  If a heat treatment by laser irradiation is adopted as the heat treatment, it is suitable for a partial heat treatment, so that only a desired portion can be heated pinpoint. For this reason, only the part equivalent to the bridge | bridging of each core sheet | seat among the outer peripheral parts of a rotor core can be demagnetized, and it can prevent that a rotor core is demagnetized more than necessary.

It is a perspective view which shows the rotor core which concerns on 1st embodiment. It is a top view which shows the core sheet which concerns on 1st embodiment. It is a schematic explanatory drawing which shows the heat processing with respect to the rotor core which concerns on 1st embodiment. It is a perspective view which shows the rotor core which concerns on 2nd embodiment. It is a top view which shows the core sheet which concerns on 2nd embodiment. It is a schematic explanatory drawing which shows the heat processing with respect to the rotor core which concerns on 2nd embodiment. It is a perspective view which shows the rotor core which concerns on 3rd embodiment. It is a top view of the 2nd core sheet which comprises the rotor core which concerns on 3rd embodiment. It is a top view which shows the modification of the 1st core sheet | seat which comprises the rotor core which concerns on 3rd embodiment. It is a top view which shows the modification of the 2nd core sheet | seat which comprises the rotor core which concerns on 3rd embodiment. It is a perspective view which shows the conventional rotor core. It is a top view which shows the conventional core sheet.

  Hereinafter, embodiments of a rotor core according to the present invention will be described with reference to the drawings. In the following description, the “rotation axis direction” refers to the direction of the axis O of the rotation axis, and the “rotation direction” refers to the clockwise direction or the counterclockwise rotation about the axis O of the rotation axis. One of the directions shall be indicated. The “magnetic pole pitch” is an angle obtained by dividing the entire circumference of the rotor core (or core sheet) 360 ° by the number of poles of the magnetic pole.

  As shown in FIG. 1, the rotor core 10 according to the first embodiment is a cylindrical laminate formed by laminating a plurality of core sheets S1 (see FIG. 2) formed of electromagnetic steel plates in a predetermined shape in the rotation axis direction. It is. As shown in FIG. 2, the core sheet S1 is provided with a plurality of magnet holes S11, and the magnet holes S11 are arranged so as to communicate with each other in the rotation axis direction, whereby the rotor core 10 has a plurality of magnet holes. Part 11 is formed. The rotor core 10 according to the present embodiment includes the four magnet hole portions 11 and the magnetic pole P is formed on the outer peripheral side, so that an inner rotor having four poles of the magnetic pole P is configured. The number of magnet hole portions 11 and the number of poles of magnetic pole P are not particularly limited as long as they are even numbers. For example, the design can be changed as appropriate according to the number of slots in the stator, the magnetic force of the magnet, the application of the rotating electrical machine, and the like. .

  In the rotor core 10 of the present embodiment, whether or not to embed a magnet in each magnet hole 11 can be arbitrarily selected. When a magnet is embedded in the magnet hole 11, the rotor core 10 is a constituent member of an IPM type rotating electrical machine rotor that uses the magnet torque of the magnet. The magnet embedded in the magnet hole 11 can be appropriately selected from, for example, a sintered magnet and a bonded magnet. On the other hand, when no magnet is embedded in the magnet hole 11, the rotor core 10 can be used as a constituent member of a rotor for a reluctance type rotating electrical machine that uses only the reluctance torque of the core magnetized by the magnetic force from the stator.

  Moreover, in this embodiment, the 1st circular hole H1 is each provided in the center part of each core sheet S1, and several 2nd circular holes H2 are each provided in the outer peripheral side, and these are rotating shafts similarly to magnet hole S11. It is arranged to communicate in the direction. For this reason, the rotor core 10 is formed with two types of through holes (first through hole TH1, second through hole TH2) having different diameters. Among these, a well-known fixing member that fixes a rotation shaft to the first through hole TH1 formed in the central portion and fixes the core sheets S1 stacked in the second through holes TH2 formed on the outer peripheral side. Shaft portions (for example, caulking pins) are respectively inserted.

  The core sheet S1 is a thin plate body made of a soft magnetic material, in which a magnetic steel sheet having a thickness of about 0.3 to 0.5 mm whose surface is insulated is formed in a predetermined shape. The core sheet S1 includes a plurality of magnet holes S11 formed at an equal pitch in an annular main body having a first circular hole H1 at the center. The magnet hole S11 of the present embodiment is configured by a slit having a predetermined width formed in a circular arc shape convex toward the first circular hole H1, and one of the longitudinal ends (circumferential directions) of the magnet hole S11. An opening A that is open at the outer periphery of the core sheet S1 is formed at the end. Further, a thin-walled bridge B (for example, approximately the same thickness as the core sheet S1) is provided between the other end and the outer peripheral portion of the core sheet S1, and the diameter is larger than the magnet hole S11 of the core sheet S1. The inner part S1i and the outer part S1o in the direction are connected to each other in a state where they are cantilevered by the bridge B.

  In the core sheet S1 of the present embodiment, each magnet hole S11 is formed to be rotationally symmetric at the magnetic pole pitch (in the present embodiment, the entire circumference of the core sheet S1 is 360 ° / 4 pole = 90 °). . Therefore, as shown in FIG. 2, when the core sheet S1 is viewed in plan, the relative positional relationship between the opening A and the bridge B with respect to the magnet hole S11 is the same in all the magnet holes S11. Specifically, the opening A is formed at the end on the same side (left side) in all the magnet holes S11. The bridge B is the same as the opening A.

  The main feature of the rotor core 10 of the present embodiment is that at least one opening A is disposed at a position adjacent to the bridge B in the rotation axis direction, and the bridge B is made nonmagnetic by a predetermined heat treatment. There is in point.

  As shown in FIGS. 1 and 3, the rotor core 10 includes a group of openings A continuously arranged in the rotation axis direction across a plurality of (four in the present embodiment) core sheets S <b> 1, and a plurality ( Each core sheet S1 is laminated so that a group of bridges B laminated in the rotation axis direction over four core sheets S1 in the embodiment are alternately arranged in the rotation axis direction. That is, in the present embodiment, a group of openings A are arranged between a group of bridges B adjacent to each other in the rotation axis direction on the outer peripheral portion of the rotor core 10 corresponding to both longitudinal ends of all the magnet hole portions 11. The group of openings A is adjacent to the bridge B arranged at the end in the rotation axis direction of the group of bridges B.

  In addition, in this embodiment, the opening part A arrange | positioned in the position which adjoins the bridge B (a group of) in the rotating shaft direction needs to be a group thing over the several core sheet | seat S1 as mentioned above. There may be only the opening A for one core sheet S1. For example, the opening A for one core sheet S1 may be disposed adjacent to the bridge B in the rotation axis direction at an arbitrary position in the rotation axis direction from one end of the rotor core 10 to the other end. Good. That is, the number of core sheets S1 formed by a group of bridges B can be appropriately selected and changed in design.

  Further, in the rotor core 10 of the present embodiment, predetermined heat treatment is performed on each bridge B, and all the bridges B are made nonmagnetic. In this embodiment, each bridge B is demagnetized by heat treatment by laser irradiation. In addition, about the heat processing by laser irradiation, since it explains in full detail in the description regarding the manufacturing method of the rotor core 10 shown below, description is abbreviate | omitted here.

  Next, the manufacturing method of the rotor core 10 of this embodiment is demonstrated. The rotor core 10 is manufactured through at least Step A, Step B, Step C, and Step D described below.

Step A is a step of preparing an electrical steel sheet that is a raw material of the core sheet S1. As the electrical steel sheet prepared in this step, for example, a soft magnetic material containing iron, silicon, silicone, or the like is formed with a constant width of 0.2 to 0.6 mm, preferably 0.3 to 0. It is rolled into a thin plate of about 5 mm and wound up to form a roll. The electromagnetic steel sheet may be a directional electromagnetic steel sheet having an easy magnetization axis in the rolling direction, or may be a so-called non-oriented electrical steel sheet in which easy magnetization axes are arranged in random directions. The surface of the electromagnetic steel sheet is subjected to a surface treatment for coating with an insulating film.

  Step B is a step of forming the core sheet S1. In the present embodiment, for example, a large number of core sheets S1 are formed by progressive press molding in which the electrical steel sheet prepared in step A is punched into a predetermined shape using one or a plurality of dies. In this step, the core sheet S1 may be integrally formed using one mold that can be formed by punching the planar shape of the core sheet S1, or each configuration of the core sheet S1 (for example, Even if a plurality of dies corresponding to the first circular hole H1, the magnet hole S11, the second circular hole H2, etc.) are used, the electromagnetic steel sheets conveyed in the longitudinal direction are sequentially punched for each configuration and formed in stages. Good.

  Step C is a step in which the core sheet S1 formed in Step B is laminated to form a cylindrical laminate. Assuming that all the core sheets S1 are conveyed to the present process with one surface on the upper surface side at the stage where the process B is completed, in the present embodiment, first, a plurality of sheets (four sheets in the present embodiment) are used. The core sheets S1 are arranged and laminated so that the magnet holes S11 communicate with each other in the rotation axis direction. Next, a plurality (four in this embodiment) of the core sheets S1 are turned over and similarly arranged so that the magnet holes S11 communicate with each other in the rotation axis direction. By laminating each core sheet S1 while repeating this alternately, each core sheet S1 is laminated so that one surface and the other surface of the core sheet S1 are in contact with each other. Thus, a cylindrical laminated body (see FIG. 1) composed of a plurality of core sheets S1 is formed.

  In this step, the step of turning the core sheet S1 upside down as described above can be omitted. For example, the magnet hole S11 and the opening A may be punched with separate dies, and the punching position of the opening A with respect to the magnet hole S11 may be punched and formed at different end portions for each of a plurality of sheets. Good. Alternatively, one magnet hole S11 and the opening A are formed by punching with one mold, and each mold forming each magnet hole S11 is rotated clockwise or counterclockwise along the outer periphery of the magnet hole S11. Alternatively, it may be formed by punching while alternately rotating a plurality of sheets by a minute angle. Even if the core sheets S1 formed in this manner are sequentially stacked without turning over each other, a plurality of core sheets S1 are stacked so that one surface of the core sheet S1 and the other surface are in contact with each other. Is substantially the same.

  Step D is a step of making the bridge B non-magnetic by performing a heat treatment on the portion corresponding to the bridge B on the outer peripheral surface of the laminate. In this embodiment, each bridge B is made nonmagnetic by heat treatment by laser irradiation. Specifically, as shown in FIG. 3, the laser L focused on the outer peripheral surface of the laminate (see the rotor core 10 shown in FIG. 1) is aligned in the direction of the rotation axis from one end to the other end of the laminate. Irradiate in a shape. This is performed with respect to the outer peripheral surface of the laminated body in which each bridge B and each opening A are arranged. At this time, only each bridge B is heated to about 800 to 1200 ° C. by laser irradiation, so that the material of the electrical steel sheet over almost the entire area of the bridge B is modified and made nonmagnetic.

  In this step, the laser L is irradiated only once in a straight line in the direction of the rotation axis from one end to the other end of the laminated body. However, the number of irradiations of the laser L, the irradiation position, and the like are regions to be demagnetized. Can be changed as appropriate according to the size of each (the width and thickness of each bridge B), the irradiation intensity of the laser L, and the like. For example, when the width of the bridge B is large, the laser irradiation may be performed a plurality of times by slightly shifting the irradiation position of the laser L in the width direction of the bridge B (the circumferential direction of the laminated body). Alternatively, when the bridge B is thick in the radial direction and the irradiation intensity of the laser L is suppressed, the laser L may be irradiated to the same irradiation position a plurality of times.

  In this step, the laser L is usually irradiated in a direction orthogonal to the stacking direction (that is, the rotation axis direction) of the stacked body. You may irradiate the laser L in the made direction. By inclining the irradiation direction of the laser L in this manner, the distance until the laser L passes through the opening A and reaches a portion other than the bridge B of the laminate increases, and the attenuation of thermal energy increases. Parts other than B can be made difficult to be heated by the laser L irradiation.

  In addition, in the manufacturing method of the rotor core 10 of this embodiment, processes other than the process A-process D mentioned above may be included. For example, between the process C and the process D, the process of fixing each core sheet S1 between lamination | stacking by the crimping pin using 2nd through-hole TH2 may be included. Alternatively, before the step D, a step of inserting the rotating shaft into the first through hole TH1 and fixing it by shrink fitting or the like may be performed. The rotor core 10 described above can be manufactured through the steps described above.

  As described above, the purpose of demagnetizing each bridge B of the rotor core 10 is mainly to reduce the leakage magnetic flux in each bridge B. Thereby, for example, when magnets are embedded in the respective magnet hole portions 11 of the rotor core 10, the magnetic characteristics of the respective magnets can be used effectively, and at the same time, the reluctance torque can be increased even when the magnets are not embedded. This is because the advantage is obtained.

  However, even in the case of performing the heat treatment by laser irradiation as described above in order to partially demagnetize only each bridge B in the rotor core 10, each bridge B is heated to about 800 to 1200 ° C. as in the prior art. There is a need. Therefore, the insulating coating formed on the surface of each core sheet S1 melts in the vicinity of each bridge B where such heat treatment is performed.

  As in the conventional rotor core 40 shown in FIG. 11, when each bridge B is continuously laminated from one end to the other end in the rotation axis direction, the insulating film near each non-magnetic bridge B is melted. The insulation between the core sheets S1 adjacent to each other in the rotation axis direction is broken, and a short circuit occurs between the laminations of the core sheets S1. Eddy currents are generated between the core sheets S1 in which the lamination is short-circuited. This eddy current increases the iron loss of the rotor core 40 and causes a reduction in the efficiency of the rotating electrical machine. In particular, the influence of eddy currents increases as the number of core sheets S1 (hereinafter referred to as a group of core sheets S1) in which the stacks are continuously short-circuited increases. For example, in the rotor core 40, it can be said that a group of core sheets S1 is constituted by all the laminated core sheets S1.

  On the other hand, in this embodiment, since the group of openings A is disposed at a position adjacent to the group of bridges B in the rotation axis direction, the core sheets S1 constituting the group of bridges B, As in the prior art, a continuous short circuit occurs between the laminated layers due to melting of the insulating coating, but between the group of bridges B and the core sheet S1 having the opening A adjacent in the rotation axis direction, the above-mentioned There is no short circuit between the layers due to heat treatment.

  Moreover, the said heat processing with respect to each bridge | bridging B is performed also in each core sheet S1 which forms a group of opening part A including the one group of opening part A adjacent to the group of bridges B in the rotation axis direction. For this reason, a continuous short circuit between the stacks occurs between the core sheets S1 forming the group of openings A, but other bridges B adjacent to the group of openings A in the rotation axis direction are provided. No short circuit between the laminates due to the heat treatment occurs between the core sheet S1.

  That is, by alternately arranging the group of openings A and the group of bridges B in the direction of the rotation axis, the number of components of the group of core sheets S1 in which a continuous short circuit has occurred between the stacks is reduced, The insulation between the stacks of the group of core sheets S1 adjacent to each other in the rotation axis direction is maintained. Therefore, in this embodiment, although all the core sheets S1 are short-circuited between any one of the core sheets S1 adjacent in the rotation axis direction, these short-circuits are intermittently generated for each group of core sheets S1. Since it is divided, the influence of the eddy current as the entire rotor core 10 is reduced.

  Thus, according to the rotor core 10 of this embodiment and the manufacturing method thereof, each core sheet is provided by disposing the (group) opening A at a position adjacent to the (group) bridge B in the rotation axis direction. It is possible to suppress a short circuit between the stacks of S1 due to the heat treatment for each bridge B. Thereby, the influence by an eddy current is reduced effectively and the iron loss increase of the rotor core 10 can be suppressed.

  Moreover, since each bridge B can be demagnetized while suppressing a short circuit between the laminations of the core sheets S1, generation of leakage magnetic flux in each bridge B can be suppressed together with an increase in iron loss of the rotor core 10. Therefore, as in the prior art, the actual benefit of reducing the leakage magnetic flux by demagnetizing the bridge B by heat treatment is not impaired by the influence of eddy current caused by the short circuit between the stacks of the core sheets S1. Therefore, compared with the conventional rotor core 40, the efficiency of the rotating electrical machine can be greatly improved.

  Furthermore, according to the rotor core 10 and the manufacturing method thereof of the present embodiment, the laminated body constituting the rotor core 10 can be formed using the core sheet S1 having the same shape, so that the cost of equipment such as molds can be reduced. Can do. Since the heat treatment (step D) by laser irradiation may be performed in a straight line in the direction of the rotation axis, a particularly precise positioning operation or the like is not required. Accordingly, it is possible to simultaneously improve the production efficiency of the rotor core 10 and reduce the product cost.

  Although the rotor core 10 and the manufacturing method thereof according to the first embodiment of the present invention have been described above, the rotor core according to the present invention can be implemented and manufactured in other forms. In the following description, items different from the rotor core 10 according to the first embodiment and the manufacturing method thereof will be mainly described, and detailed descriptions regarding common items will be omitted.

  For example, you may implement with a form like the rotor core 20 shown in FIG. The rotor core 20 according to the second embodiment is different from the above-described rotor core 10 in the arrangement of the opening A and the bridge B at both ends in the longitudinal direction of each magnet hole 21. Specifically, the rotor core 20 of the present embodiment mainly includes a bridge B and an opening A provided in the core sheet S2 (see FIG. 5) alternately in the rotation axis direction for each core sheet S2. It is characterized by being arranged adjacent to each other.

  As shown in FIG. 5, the core sheet S <b> 2 is provided with a bridge B at one of the longitudinal ends of each magnet hole S <b> 21 and an opening A at the other end. However, each of the magnet holes S21 of the core sheet S2 is symmetrical with respect to a midpoint between the magnetic poles P adjacent in the circumferential direction and a virtual line passing through the axis O. This is different from the core sheet S1 in that it is formed. That is, the relative positional relationship between the opening A and the bridge B with respect to the magnet hole S21 when the core sheet S2 is viewed in plan is different between the magnet holes S21 adjacent in the circumferential direction. Specifically, in the magnet hole S21 adjacent in the circumferential direction of the core sheet S2, the opening A is provided at an end portion (on the right side or the left side) different from each other. The bridge B is the same as the opening A.

  In addition, the core sheet S2 constituting the rotor core 20 is provided with a plurality of core caulkings K for fixing between the laminations of the core sheets S2. Each core caulking K is arranged at a position that is rotationally symmetric at the magnetic pole pitch. In the present embodiment, the core caulking K is provided in each of the inner part S2i and the outer part S2o of the core sheet S2, but the core caulking K may be provided only in one of them. In addition, the core caulking K of the present embodiment employs a so-called V-protrusion caulking in which the cross section in the rotation axis direction protrudes in a V shape, but other forms such as a dowel caulking may be used.

  The rotor core 20 of this embodiment can be manufactured by the same manufacturing method as the above-described rotor core 10 except for the following points. Specifically, it is as follows.

  In the present embodiment, a large number of core sheets S2 are punched and formed in place of the core sheet S1 in the same manner as in the step B. Here, in the core sheet S2 of the present embodiment, as described above, each magnet hole S21 of the core sheet S2 has an imaginary line passing through the midpoint between the magnetic poles P adjacent in the circumferential direction and the axis O as the axis of symmetry. It differs from the core sheet S1 in that it is formed to be line symmetric. However, for example, if the punching position of the die with respect to the electromagnetic steel sheet and the punching timing are appropriately changed, the formation position of the opening A with respect to the magnet hole S21 can be easily changed. Can be formed. In addition, each core caulking K is formed at a predetermined position.

  Further, similarly to the above step C, a plurality of cores in which the bridges B and the openings A provided in the core sheet S2 are alternately arranged adjacent to each other in the rotation axis direction for each core sheet S2. A cylindrical laminate (see FIG. 4) made of the sheet S2 is formed. In the present embodiment, the core sheet S2 to be newly laminated is laminated while being rotated relatively with the magnetic pole pitch one by one with respect to the already laminated core sheet S2. By laminating the core sheets S2 in this manner, the magnet holes S21 are arranged so as to communicate with each other in the rotation axis direction, and the opening A and the bridge B are arranged in the rotation axis direction for each core sheet S2. It will be arranged alternately next to each other.

  On the other hand, since each core sheet S2 is provided with a plurality of core caulking K at a position that is rotationally symmetric at the magnetic pole pitch, a concave portion of each core caulking K formed on one surface side of the already laminated core sheet S2, Each core sheet S2 is sequentially laminated while the projections of the respective core caulking K formed on the other surface side of the newly laminated core sheet S2 are engaged with each other. Therefore, in the present embodiment, a desired laminate can be formed while sequentially fixing the stacks of the core sheets S2 while being easily positioned by the core caulking K, and between the stacks of the core sheets S2 is further increased. It can be firmly fixed.

  As a method of rotating the newly laminated core sheet S2 relative to the already laminated core sheet S2, for example, a method of directly rotating the newly laminated core sheet S2, or a previously laminated core For example, a method of rotating a receiving side such as a holder on which the sheet S2 is placed may be used. Alternatively, when punching and forming the core sheet S2 in the process B, the punching position of the mold is changed, and each magnet hole S21 of the newly laminated core sheet S2 is made relative to the already laminated core sheet S2. Alternatively, it may be formed by punching so that the positional relationship is substantially the same as that of the rotation.

  Furthermore, as shown in FIG. 6, each bridge B is irradiated by irradiating a portion corresponding to each bridge B in the outer peripheral portion of the laminated body made up of a plurality of core sheets S2 in the same manner as in the above step D. Heat treatment for demagnetizing is performed. Here, the point to be noted in the present embodiment is that even when such a heat treatment is performed on each bridge B, no short circuit occurs between the laminations of the core sheets S2.

  That is, in this embodiment, since the openings A are always adjacent to both ends in the rotational axis direction of all the bridges B, even if the insulating coating melts in the vicinity of each bridge B during the heat treatment, There is no continuous short circuit between the laminations of the core sheets S2, and insulation is maintained between the laminations of all the core sheets S2. Therefore, each core sheet S2 constituting the rotor core 20 is not formed with a portion in which a continuous short circuit occurs between the layers in the vicinity of each bridge B, unlike the group of core sheets S1 described above.

  According to the rotor core 20 and the manufacturing method thereof of the present embodiment, each bridge B can be demagnetized while maintaining the insulation between the laminations of all the core sheets S2, resulting in a short circuit between the laminations of the core sheets S2. Generation of eddy currents can be reliably prevented. As a result, the iron loss of the core can be further reduced compared to the rotor core 10 described above, and the efficiency of the rotating electrical machine can be significantly improved.

  Moreover, you may implement with a form like the rotor core 30 shown in FIG. The rotor core 30 according to the third embodiment is not composed of core sheets (S1, S2) having the same shape, but includes a plurality of types of core sheets having different shapes. (10, 20). Specifically, the rotor core 30 of the present embodiment mainly includes a first core sheet (the conventional core sheet S shown in FIG. 12 in the present embodiment) and a second core sheet S3 (see FIG. 8). It is characterized by.

  The first core sheet S is provided with bridges B at both longitudinal ends of each magnet hole S41. On the other hand, as shown in FIG. 8, the second core sheet S3 is provided with openings A at both ends in the longitudinal direction of each magnet hole S31. In the rotor core 30 of the present embodiment, the first core sheet S and the second core sheet S3 are alternately stacked one by one in the rotation axis direction. Therefore, the arrangement of the openings A and the bridges B at both longitudinal ends of each magnet hole 31 is substantially the same as that of the rotor core 20 described above.

  In the rotor core 30 of this embodiment, it is preferable that the 1st core sheet | seat S is arrange | positioned at the both ends of a rotating shaft direction. Thereby, since the second core sheet S3 can be sandwiched and held between the first core sheets S, the mechanical strength of the rotor core 30 is increased.

  Further, in the rotor core 30 of the present embodiment, the first core sheet S and the second core sheet S3 are respectively laminated via an adhesive layer (not shown) (for example, a core varnish). For example, the second circular hole H2 (see FIGS. 2 and 5) described above can be used as long as the mechanical strength of the rotor core 30 can be sufficiently ensured by fixing between the laminated core sheets adjacent to each other in the rotation axis direction via the adhesive layer. ) And core caulking K (see FIG. 5) need not be formed on each core sheet (S, S3). Thereby, while preventing the flow of magnetic flux from being inhibited, the magnetic resistance of the core can be reduced.

  The rotor core 30 of this embodiment can be manufactured by the same manufacturing method as the above-described rotor cores 10 and 20 except for the following points. Specifically, it is as follows.

  In the present embodiment, like the step B, the first core sheet S and the second core sheet S3 having different shapes are punched and formed using a predetermined mold. The difference in shape between the first core sheet S and the second core sheet S3 is whether the bridges B are provided at the longitudinal ends of the magnet holes (S41, S31) or the openings A are provided. Therefore, for example, if a mold for punching each magnet hole S41 of the first core sheet S and a mold for punching each magnet hole S31 of the second core sheet S3 are prepared and operated alternately, The core sheet S and the second core sheet S3 are alternately formed. Alternatively, a mold for punching each magnet hole S41 of the first core sheet S and a mold for punching only each opening A of the second core sheet S3 are prepared, and the mold for punching the magnet hole S41 is always operated. You may comprise so that the metal mold | die which punches only each opening part A may be operated intermittently.

  Here, in this embodiment, if the core varnish is applied to the surfaces of the first core sheet S and the second core sheet S3 to form an adhesive layer and these are simply laminated alternately, It is possible to form a laminate in which the openings A and the bridges B at both longitudinal ends are substantially the same as the rotor core 20 described above. Therefore, according to the rotor core 30 and the manufacturing method thereof according to the present embodiment, the above-described process B and process C can be simplified while the same effect as the above-described rotor core 20 can be obtained, so that the production efficiency can be improved. Can do.

  In the present embodiment, in the second core sheet S3, each front end portion (shaded portion in FIG. 8) of the inner portion S3i located between the magnetic poles of the rotor core 30 may be cut. In that case, a recess that is retreated by a predetermined distance in the radial direction from the outer peripheral portion of the second core sheet S3 is formed between the openings A adjacent in the circumferential direction, and the outer peripheral portion of the rotor core 30 is provided in the circumferential direction. Substantially wide openings that are wider than the openings A are provided at intervals between the magnetic poles P at equal pitches in the circumferential direction, and are alternately arranged in the direction of the rotation axis for each core sheet.

  Moreover, the rotor core 30 of this embodiment is replaced with the above-mentioned 1st core sheet S and 2nd core sheet S3, 1st core sheet S '(refer FIG. 9) and 2nd core sheet S3' (refer FIG. 10). You may be comprised from. The first core sheet S ′ and the second core sheet S3 ′ are each provided with a second bridge B ′ at a position different from the longitudinal ends of the magnet holes (S41, S31). The second bridge B ′ is disposed at the center in the longitudinal direction of each magnet hole (S41, S31), but may be formed at any position as long as the position is different from the end in the longitudinal direction. By providing the second bridge B ′ in each magnet hole (S41, S31), the mechanical strength of the rotor core can be improved. Thereby, while improving the dimensional accuracy of a finished product, the deformation | transformation of the rotor core during production or use of a rotary electric machine can be suppressed.

  The present invention can be implemented in a mode in which various improvements, modifications, or variations are added based on the knowledge of those skilled in the art without departing from the spirit of the present invention. Moreover, you may implement with the form which substituted any invention specific matter to the other technique within the range which the same effect | action or effect produces.

  For example, in the present invention, the heat treatment for the bridge of each core sheet constituting the rotor core is not limited to the laser irradiation, and any method is adopted as long as only each bridge can be partially demagnetized. can do. Specifically, it is possible to apply heat treatment by various methods such as heating by TIG welding or plasma arc welding, electron beam irradiation, high frequency heating, and the like. In particular, a heat treatment in which the amount of heat attenuates depending on the distance from the heat source or the distance from the focal point is suitable.

  Further, in each of the rotor cores (10, 20, 30) according to the above-described embodiments, the magnet hole of each core sheet is formed in an arc shape, but the shape of the magnet hole is not particularly limited, and the design is appropriately changed. May be. For example, substantially concave magnet holes in which flux barriers are formed at both longitudinal ends of a square slit, or magnet holes in which square slits are formed radially along the radial direction of the core sheet at an equal pitch in the circumferential direction. A plurality of core sheets may be used.

  Furthermore, the rotor cores (10, 20, 30) according to the above-described embodiments are all inner rotors, but the present invention can also be applied to outer rotors.

10, 20, 30, 40 Rotor core 11, 21, 31, 41 Magnet hole TH1 First through hole TH2 Second through hole P Magnetic pole S1, S2 Core sheet S, S ′ First core sheet S3, S3 ′ Second core Sheet A Aperture B Bridge B 'Second Bridge Si, S1i, S2i, S3i Inner part So, S1o, S2o, S3o Outer part K Core caulking L Laser O Center of rotation axis

Claims (15)

A cylindrical rotor core that is formed by laminating a plurality of core sheets formed of electromagnetic steel sheets in a predetermined shape in the rotation axis direction, and arranged so that a plurality of magnet holes provided in the core sheet communicate in the rotation axis direction. There,
An opening in which an end of the magnet hole is opened at the outer periphery of the core sheet;
A bridge provided between an end portion of the magnet hole and an outer peripheral portion of the core sheet,
At least one opening is disposed at a position adjacent to the bridge in the rotation axis direction,
The rotor core, wherein the bridge is demagnetized by heat treatment.   The rotor core according to claim 1, wherein the bridge and the opening are alternately arranged in the rotation axis direction for each of the core sheets. In the core sheet,
The bridge according to claim 1 or 2, wherein the bridge is provided at one of the ends of the magnet hole and the opening is provided at the other end. Rotor core. The core sheet is
A first core sheet provided with the bridge at both ends of each magnet hole;
The rotor core according to claim 1, further comprising: a second core sheet provided with the opening at both ends of each magnet hole.   The rotor core according to claim 4, wherein the first core sheet is disposed at both ends in the rotation axis direction.   The core caulking which fixes between the lamination | stacking of the said core sheet is provided in either the outer side or inner side part of the radial direction rather than the said magnet hole of the said core sheet, It is characterized by the above-mentioned. The rotor core according to claim 5.   The rotor core according to any one of claims 1 to 5, wherein the core sheet is laminated via an adhesive layer.   The rotor core according to claim 1, wherein the core sheet includes a second bridge provided at a position different from an end of the magnet hole. A cylindrical rotor core formed by laminating a plurality of core sheets formed of electromagnetic steel sheets in a predetermined shape in the rotation axis direction, and arranged so that a plurality of magnet holes provided in the core sheet communicate in the rotation axis direction. A manufacturing method comprising:
Step A for preparing the electromagnetic steel sheet;
Step B for punching the magnetic steel sheet into a predetermined shape by one or a plurality of molds to form a plurality of the core sheets;
A plurality of the core sheets are stacked in the direction of the rotation axis, and an opening in which the end of the magnet hole is opened at the outer periphery of the core sheet, and between the end of the magnet hole and the outer periphery of the core sheet Forming a cylindrical laminated body in which at least one of the openings is disposed at a position adjacent to the bridge in the rotation axis direction;
Performing a heat treatment on a portion corresponding to the bridge in the outer peripheral surface of the laminate, and demagnetizing the bridge; and
A method for manufacturing a rotor core, comprising: In step C,
10. The method of manufacturing a rotor core according to claim 9, wherein the core sheets are laminated so that the bridges and the openings are alternately arranged in the rotation axis direction for each of the core sheets. . In step B,
The core sheet in which the bridge is provided at any one of the ends of the magnet hole and the opening is provided at the other end, is formed. A method for producing a rotor core according to claim 1. In step B,
Forming the core sheet in which the position of the bridge with respect to the magnet hole is the same in each magnetic pole;
In step C,
The method for manufacturing a rotor core according to claim 11, wherein the core sheets are laminated so that one surface and the other surface of the core sheet are in contact with each other for each of the one or more core sheets. In step B,
Forming the core sheet in which the position of the bridge with respect to the magnet hole is alternately different for each magnetic pole;
In step C,
The rotor core manufacturing method according to claim 11, wherein the core sheets are stacked while being relatively rotated at a magnetic pole pitch for each of the one or a plurality of the core sheets. In step B,
A first core sheet provided with the bridge at both ends of the magnet hole;
11. The method of manufacturing a rotor core according to claim 9, wherein a second core sheet having the openings provided at both ends of the magnet hole is formed.   The method for manufacturing a rotor core according to any one of claims 9 to 14, wherein the heat treatment performed in the step D is a laser heat treatment.

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