JP5561542B2 - Permanent magnet rotor and manufacturing method thereof - Google Patents

Description

  The present invention relates to a permanent magnet rotor used in a permanent magnet motor and a method for manufacturing the same.

  Conventionally, various electric motors that convert electrical energy into mechanical energy are known. FIG. 7 is a cross-sectional view of a general permanent magnet motor 100 perpendicular to the direction of the rotation axis 101. As shown in FIG. 7, the permanent magnet motor 100 includes a stator 102 and a permanent magnet rotor 70. The stator 102 has a stator core 104 in which a pole tooth portion 103 is formed, and a winding 105 is wound around the pole tooth portion 103. The permanent magnet rotor 70 has a rotor magnetic core 74 in which a magnet insertion hole 72 is formed, and a permanent magnet 76 is inserted into the magnet insertion hole 72.

  When a current having a predetermined voltage value, current value, and frequency flows through the winding 105, a rotating magnetic field is generated in the pole tooth portion 103 of the stator core 104. In synchronization with this rotating magnetic field, the permanent magnet rotor 70 rotates around the rotating shaft 101. The permanent magnet motor 100 transmits the driving force obtained by the change of the magnetic field to another mechanism via the rotating shaft 101.

  As shown in FIG. 8, the rotor magnetic core 74 is formed by laminating electromagnetic steel plates having the same shape, whose surfaces are insulated, in the axial direction. An opening hole punched out by press working is formed in the electromagnetic steel plate, and the magnet insertion hole 72 is made by overlapping the opening holes. For this reason, the magnet insertion hole 72 has high dimensional accuracy. On the other hand, the permanent magnet 76 is formed through processes such as molding, sintering, and processing. For this reason, the permanent magnet 76 varies in dimensional accuracy among individuals.

  The following patent document discloses a method for fixing a permanent magnet to a rotor core in consideration of variations in the size of the permanent magnet. For example, a method of fixing using an adhesive (Patent Document 1), a method of fixing a projection provided on a rotor magnetic core by bending it in an axial direction (Patent Document 2), and fixing a magnet by deforming a part of the rotor magnetic core Fixing method for providing protrusions (Patent Documents 3 and 4), fixing method by laser welding (Patent Document 5), fixing method by holding pieces covering individual permanent magnets (Patent Document 6), rotor core in the circumferential direction There is a fixing method for shifting (Patent Document 7).

  The permanent magnet fixing method described above is mainly intended for fixing in the radial direction or the circumferential direction. Apart from this, the end plate 78 (see FIG. 8B) closes the magnet insertion hole 72 to prevent the permanent magnet 76 from dropping off in the axial direction (Patent Document 8).

  In a hermetic or semi-hermetic compressor used for an air conditioner or the like, a permanent magnet motor is placed in a refrigerant. In this case, the permanent magnet rotor is also exposed to the refrigerant. For this reason, in addition to the normal mechanical strength, the permanent magnet rotor is required to have durability against chemical strength and temperature change (refrigerant resistance).

  However, the permanent magnet fixing method described above is not preferable for use in an environment where the permanent magnet rotor is exposed to the refrigerant because fixing may be incomplete due to the following reasons. For example, adhesive deterioration due to the influence of refrigerant and temperature change (Patent Document 1), fixing means deformation due to temperature change (Patent Documents 2, 3 and 4), difference in thermal expansion coefficient and disengagement due to temperature change (Patent Document 1) Reference 5), differences in the fixing strength of the permanent magnets due to variations in the size of the permanent magnets (Patent Documents 6 and 7), and the like are cited as main causes.

  Further, the magnet insertion hole 72 of the rotor magnetic core 74 is formed larger than the permanent magnet 76 in consideration of variation in the dimensions of the permanent magnet 76. Therefore, a gap 79 is formed between the permanent magnet 76 and the magnet insertion hole 72 before fixing. The permanent magnet 76 is firmly fixed so that it does not move in the magnet insertion hole 72 even if the permanent magnet rotor 70 rotates.

  However, if the permanent magnet 76 is not completely fixed as described above, the permanent magnet 76 moves in the magnet insertion hole 72 when the permanent magnet rotor 70 rotates. Since the size of the permanent magnet 76 varies, the size and shape of the gap 79 are not constant. For this reason, the movement of the permanent magnet 76 moving in the magnet insertion hole 72 becomes irregular, and there is a possibility that smooth rotation of the rotating shaft 101 is hindered. The influence of the movement of the permanent magnet 76 on the rotation of the rotating shaft 101 becomes more noticeable as the size of the permanent magnet rotor 70 increases.

JP 2000-197291 A JP 2001-37121 A Japanese Patent Laid-Open No. 9-191590 Japanese Patent Laid-Open No. 5-260686 JP 2000-83334 A JP 2003-143786 A JP 2007-49803 A JP 2009-1331026 A

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a permanent magnet rotor suitable for a permanent magnet motor driven in a refrigerant. More specifically, an object of the present invention is to provide a permanent magnet rotor in which the fixed state of the permanent magnet with respect to the rotor core does not change with time even in an environment exposed to a refrigerant.

  The permanent magnet rotor of the present invention includes a tubular hollow member having an inner surface and an outer surface, a rotor magnetic core disposed on the outer surface side of the hollow member and having a magnet insertion hole formed therein, and inserted into the magnet insertion hole. And the hollow member is expanded by an internal pressure applied to the inner surface, the magnet insertion hole is deformed, and the permanent magnet is pressed and fixed to the rotor magnetic core. To do.

  The permanent magnet rotor of the present invention includes a tubular hollow member having an inner surface and an outer surface, a rotor magnetic core disposed on the outer surface side of the hollow member and having a magnet insertion hole formed therein, and inserted into the magnet insertion hole. A permanent magnet, and a through hole that leads from the inner surface of the rotor core to the magnet insertion hole, and the hollow member is expanded by internal pressure applied to the inner surface, and the hollow member is formed in the through hole. And the permanent magnet is pressed and fixed to the rotor magnetic core.

  The permanent magnet rotor of the present invention is disposed between a tubular hollow member having an inner surface and an outer surface, an annular holding member disposed on the outer surface side of the hollow member, and the hollow member and the holding member. A permanent magnet and a rotor magnetic core disposed on the inner surface side of the hollow member, and the hollow member, the permanent magnet, and the holding member are integrated by tube expansion forming an internal pressure on the inner surface of the hollow member. And attached to the outer surface of the rotor magnetic core.

  Further, in the method of manufacturing a permanent magnet rotor according to the present invention, the tube expansion molding includes the step of applying an internal pressure by the liquid pressure of the liquid filled in the hollow portion of the hollow member to expand the hollow member in the radial direction. Including.

  The tube expansion molding may include a step of passing the molding jig inserted into the hollow portion of the hollow member in the axial direction along the inner surface of the hollow member to expand the diameter of the hollow member. .

  According to the permanent magnet rotor of the present invention, the outer surface of the hollow member presses the contact surface with the rotor core in the tube expansion forming process, so that the magnet insertion hole is deformed. The permanent magnet inserted into the magnet insertion hole is pressed by a part of the inner surface of the deformed magnet insertion hole and fixed to the rotor magnetic core. The rotor core is hardly deformed due to temperature changes. For this reason, even in an environment exposed to a refrigerant, a change with time hardly occurs in the fixed state of the permanent magnet with respect to the rotor core. Thereby, the permanent magnet rotor suitable for the permanent magnet electric motor driven in a refrigerant | coolant can be provided.

  Further, according to the permanent magnet rotor according to the present invention, in the tube expansion molding process, the permanent magnet inserted into the magnet insertion hole is pressed against the outer surface of the hollow member deformed along the through hole and fixed to the rotor core. Is done. The hollow member hardly deforms due to temperature change or the like. For this reason, even in an environment exposed to a refrigerant, a change with time hardly occurs in the fixed state of the permanent magnet with respect to the rotor core. Thereby, the permanent magnet rotor suitable for the permanent magnet electric motor driven in a refrigerant | coolant can be provided.

  Further, according to the permanent magnet rotor according to the present invention, the hollow member, the permanent magnet, and the holding member are integrated in the tube expansion molding process. The hollow member and the holding member are hardly deformed by a temperature change or the like. For this reason, even in an environment exposed to a refrigerant, changes with time hardly occur in the fixed state of the integrated hollow member, permanent magnet, and holding member. Thereby, the permanent magnet rotor suitable for the permanent magnet electric motor driven in a refrigerant | coolant can be provided.

  According to the method of manufacturing a permanent magnet rotor according to the present invention, the step of applying an internal pressure to the inner surface of the hollow member by the liquid pressure of the liquid filled in the hollow portion of the hollow member to expand the hollow member in the radial direction. Tube expansion including As a result, even in an environment exposed to a refrigerant, the permanent magnet is hardly changed over time in the fixed state of the permanent magnet with respect to the rotor core, and regardless of variations in the size of the permanent magnet. Can be firmly fixed. In addition, since no special member or material for fixing the permanent magnet is required, the manufacturing process can be reduced and the production efficiency of the permanent magnet rotor can be improved. In short, the manufacturing method is a manufacturing method particularly suitable as a manufacturing method of a permanent magnet rotor used in a permanent magnet motor driven in a refrigerant.

  Even if a molding method including a step of expanding the diameter of the hollow member by passing the molding jig inserted into the hollow part of the hollow member in the axial direction along the inner surface of the hollow member as the pipe expansion molding, Similar effects can be obtained.

It is the (a) cross-sectional view which followed the A1-A1 line which shows the permanent magnet rotor which concerns on 1st embodiment, and (b) the longitudinal cross-sectional view which followed the A2-A2 line. It is explanatory drawing of the process in which a hollow member is pipe-expanded. It is the (a) transverse cross-sectional view which followed the B1-B1 line which shows the permanent magnet rotor which concerns on 2nd embodiment, and (b) the longitudinal cross-sectional view along the B2-B2 line. It is the cross-sectional view along the (a) C1-C1 line which shows the modification of the permanent magnet rotor which concerns on 2nd embodiment, and the longitudinal cross-sectional view along the (b) C2-C2 line. It is the cross-sectional view along the (a) D1-D1 line which shows the other modification of the permanent magnet rotor which concerns on 2nd embodiment, and the longitudinal cross-sectional view along the (b) D2-D2 line. It is the (a) transverse cross section which followed the E1-E1 line which shows the permanent magnet rotor which concerns on 3rd embodiment, and (b) the longitudinal cross-sectional view along the E2-E2 line. It is a cross-sectional view of a general permanent magnet motor. It is the (a) cross-sectional view which shows the conventional permanent magnet rotor, and (b) the longitudinal cross-sectional view along XX.

  Hereinafter, embodiments of a permanent magnet rotor according to the present invention will be described with reference to the drawings. In the present specification, each drawing is schematically shown, and when the same reference numeral is given, the same configuration is shown. Moreover, in the longitudinal cross-sectional view of the permanent magnet rotor shown in each drawing, each rotor magnetic core is abbreviate | omitting and showing the display of the laminated electromagnetic steel plate for the convenience of a code | symbol display.

  As shown in FIG. 1, the permanent magnet rotor 10 according to the first embodiment includes a hollow member 11, a rotor core 14 in which a magnet insertion hole 12 is formed, and a permanent magnet 16 that is inserted into the magnet insertion hole 12. And comprising. The hollow member 11 is expanded and formed by an internal pressure applied to the inner surface. Accordingly, the magnet insertion hole 12 is deformed, and the permanent magnet 16 is pressed and fixed to the rotor magnetic core 14.

  The hollow member 11 is a tubular member having an inner surface 11a and an outer surface 11b. The shape of the hollow member 11 is not particularly limited because it can be deformed by tube expansion molding, but it is preferably a shape close to the shape of the inner surface of the rotor magnetic core 14 in terms of ease of processing work and improvement of work efficiency. In the present embodiment, a cylindrical hollow member 11 is used. The size of the hollow member 11 is appropriately determined according to the size of the inner surface of the rotor magnetic core 14 and the like. As a material of the hollow member 11, a material having chemical strength and durability against temperature change (refrigerant resistance) in addition to normal mechanical strength is used.

  The rotor magnetic core 14 is a cylindrical component formed by laminating electromagnetic steel plates having the same shape (annular shape in plan view) whose surfaces are insulated in the axial direction. A plurality of opening holes punched by press working are formed in this electromagnetic steel sheet. In the present embodiment, a plurality of magnet insertion holes 12 are formed in the rotor magnetic core 14 by overlapping the opening holes. For this reason, it is desirable that the electromagnetic steel sheet constituting the rotor magnetic core 14 has a sufficient radial thickness in order to prevent deformation (warping or the like) during press working. By forming the rotor magnetic core 14 in this way, the magnet insertion hole 12 can be formed with high dimensional accuracy. The rotor magnetic core 14 is disposed on the outer surface 11 b side of the hollow member 11. The size of the rotor magnetic core 14 is appropriately designed according to the size and structure of the electric motor employed, the size of the opposing stator (particularly the pole tooth portion), and the like.

  The permanent magnet 16 is a plate-like magnet having magnetic pole faces having different polarities (N pole and S pole) facing each other. The permanent magnet 16 is inserted into the magnet insertion hole 12 formed in the rotor magnetic core 14. At this time, the magnetic pole surfaces of the adjacent permanent magnets 16 are arranged to have different polarities. That is, the permanent magnets 16 are arranged so that the polarities are alternately different in the circumferential direction of the rotor core 14. The shape and size of the permanent magnet 16 are appropriately designed and formed according to the shape and size of the magnet insertion hole 12. For example, a neodymium magnet having a high coercive force and not easily demagnetized is preferably used as the permanent magnet 16, but other types of magnets (for example, a ferrite magnet, a samarium cobalt magnet, etc.) may be used.

  As shown in FIG. 2, the permanent magnet rotor 10 of the present embodiment is subjected to tube expansion molding on the hollow member 11 described above. The tube forming process will be described in detail below. In addition, the arrow shown by FIG.2 (b) shall show the internal pressure applied to the inner surface 11a of the hollow member 11. FIG.

  FIG. 2A shows a process of preparing for tube expansion molding. In the process, the hollow member 11, the rotor magnetic core 14, and the permanent magnet 16 are each arranged at the predetermined position. In a state before the tube expansion molding is performed, a gap 19 a is formed between the outer surface 11 b of the hollow member 11 and the inner surface 14 a of the rotor magnetic core 14. Further, the magnet insertion hole 12 is formed to be slightly larger than the dimension of the permanent magnet 16 in consideration of variation in the dimension of the permanent magnet 16. Therefore, a gap 19 b is also formed between the magnet insertion hole 12 and the permanent magnet 16.

  FIG. 2B shows a process of deforming the hollow member 11. In this process, the hollow member 11 is expanded in the direction of the outer surface 11b by applying an internal pressure to the inner surface 11a. Thereafter, there is no gap 19a (see FIG. 2A) between the outer surface 11b of the expanded hollow member 11 and the inner surface 14b of the rotor magnetic core 14, and these contact each other. When the internal pressure is further applied, the outer surface 11b of the hollow member 11 presses the inner surface of the rotor magnetic core 14 in the radial direction.

  In the present embodiment, tube expansion molding includes a step of applying an internal pressure to the inner surface 11a by a liquid pressure of a liquid (not shown) filled in the hollow portion 11c of the hollow member 11 to expand the hollow member 11 in the radial direction. Done. The outer surface 11 b of the expanded hollow member 11 is plastically deformed along the inner surface 14 a of the rotor magnetic core 14.

  FIG. 2 (c) shows the permanent magnet rotor 10 after tube expansion molding. The portion where the distance between the inner surface 14a of the rotor core 14 and the magnet insertion hole 12 is the shortest (thinned portion T (see FIG. 2B)) is more easily deformed by applying an external force than the other portions. . Therefore, in the step shown in FIG. 2B, when an internal pressure is further applied to the inner surface 11a of the hollow member 11, the thin portion T of the rotor magnetic core 14 is pressed against the outer surface 11b of the hollow member 11 in the radial direction. Deform. As a result, the magnet insertion hole 12 is deformed, and a part of the inner surface of the magnet insertion hole 12 and the permanent magnet 16 come into contact.

  The permanent magnet 16 is pressed in the radial direction by a part of the inner surface (contact surface C) of the deformed magnet insertion hole 12 and is fixed to the rotor magnetic core 14. That is, the permanent magnet 16 is fixed in a state of being sandwiched between the inner surfaces of the magnet insertion holes 12 opposed in the radial direction. Further, in order to prevent the permanent magnet 16 from falling off in the axial direction, the end plate 18 closes the magnet insertion hole 12 (see FIG. 1B). In this way, the permanent magnet rotor 10 according to this embodiment is manufactured.

  According to the permanent magnet rotor 10 according to the present embodiment, the outer surface 11b of the hollow member 11 presses the contact surface (the inner surface 14a) with the rotor magnetic core 14 in the tube expansion molding process, whereby the magnet insertion hole 12 is formed. Deform. The permanent magnet 16 inserted into the magnet insertion hole 12 is pressed by a part of the inner surface (contact surface C) of the deformed magnet insertion hole 12 and fixed in the radial direction of the rotor core 14. The rotor magnetic core 14 hardly deforms due to a temperature change or the like. For this reason, even in an environment exposed to a refrigerant, the temporal change hardly occurs in the fixed state of the permanent magnet 16 with respect to the rotor magnetic core 14. Thereby, the permanent magnet rotor suitable for the permanent magnet electric motor driven in a refrigerant | coolant can be provided.

  Further, according to the permanent magnet rotor 10 according to the present embodiment, since the magnet insertion hole 12 is deformed in the radial direction, the permanent magnet 16 does not move in the magnet insertion hole 12. For this reason, the rotating shaft 101 can be smoothly rotated irrespective of the difference in the size and shape of the gap 19b caused by the variation in the dimensions of the permanent magnets 16. In addition, by deforming the magnet insertion hole 12, the area (volume) of the gap 19b formed between the permanent magnet 16 can be reduced. Thereby, the reduction of magnetic permeability can be prevented.

  Furthermore, according to the permanent magnet rotor 10 according to the present embodiment, a part of the rotor magnetic core 14 is deformed to fix the permanent magnet 16, so that the permanent magnet 16 is independent of the dimensional variation of each permanent magnet 16. Can be firmly fixed. Such a fixing method of the permanent magnet 16 does not require a special member or material for fixing the permanent magnet 16, so that the manufacturing process can be reduced and the production efficiency of the permanent magnet rotor 10 is improved. be able to.

  Further, according to the method for manufacturing the permanent magnet rotor 10 according to the present embodiment, the internal pressure is applied to the inner surface 11a of the hollow member 11 by the liquid pressure of the liquid filled in the hollow portion 11c of the hollow member 11, and the hollow member 11 is hollow. Tube expansion forming including a step of expanding the member 11 in the radial direction is performed. Thus, as described above, the permanent magnet 16 can be fixed to the rotor core 14 by a fixing method suitable for the refrigerant environment. That is, it can be said that this manufacturing method is a particularly suitable manufacturing method as a manufacturing method of the permanent magnet rotor used for the permanent magnet motor driven in the refrigerant.

  If the permanent magnet rotor 10 according to the present embodiment is used in a permanent magnet motor that is driven in a refrigerant, the permanent magnet 16 is fixed to the rotor core 14 over time even in an environment exposed to the refrigerant. The change hardly occurs and the permanent magnet 16 does not move in the magnet insertion hole 12. For this reason, smooth rotation can be obtained even if the permanent magnet rotor 10 is enlarged. Therefore, the permanent magnet motor can be increased in size.

  As mentioned above, although the permanent magnet rotor 10 which concerns on 1st embodiment of this invention was demonstrated, the permanent magnet rotor which concerns on this invention can be implemented with another form.

  For example, an embodiment like the permanent magnet rotor 20 shown in FIG. 3 may be used as the second embodiment. The permanent magnet rotor 20 includes a hollow member 11, a rotor magnetic core 24 in which the magnet insertion hole 12 is formed, a permanent magnet 16 inserted into the magnet insertion hole 12, and a magnet insertion hole from the inner surface 24 a of the rotor magnetic core 24. And a through-hole 23 communicating with 12. In the present embodiment, the hollow member 11 is expanded by an internal pressure applied to the inner surface. Along with this, the hollow member 11 is deformed along the through hole 23, and the permanent magnet 16 is pressed and fixed to the rotor magnetic core 24.

  The rotor magnetic core 24 is a cylindrical part formed by laminating electromagnetic steel plates having the same shape (annular shape in plan view) whose surfaces are insulated in the axial direction. A plurality of opening holes punched by press working are formed in this electromagnetic steel sheet. In the present embodiment, a plurality of magnet insertion holes 12 are formed in the rotor magnetic core 24 by overlapping the opening holes. Here, among the electromagnetic steel sheets in which the opening holes are formed, a part of the electromagnetic steel sheets is formed with a through portion that leads from the inner surface 24a of the rotor magnetic core 24 to the opening. A through hole 23 is formed in the rotor magnetic core 24 by overlapping the through portions.

  Also in this embodiment, the process similar to the process of pipe expansion molding of the hollow member 11 mentioned above is performed. For this reason, in the following description, only the feature point of the permanent magnet rotor 20 according to the present embodiment will be described, and the description of the same process that exhibits the same operation as the tube expansion molding will be omitted. The same applies to the description of other embodiments described later.

  In the step of deforming the hollow member 11 (see FIG. 2B), the hollow member 11 to which the internal pressure is applied to the inner surface 11a expands in the radial direction, and the outer surface 11b contacts the inner surface 24a of the rotor magnetic core 24. When this internal pressure is further applied, the hollow member 11 is plastically deformed along the inner surface 24 a of the rotor magnetic core 24, and the outer surface 11 b is deformed along the through hole 23, and the permanent magnet 16 inserted into the magnet insertion hole 12. Contact. When an internal pressure is further applied from here, the outer surface 11 b of the hollow member 11 presses the permanent magnet 16 in the radial direction, and the permanent magnet 16 is fixed to the rotor magnetic core 24.

  According to the permanent magnet rotor 20 according to the present embodiment, the permanent magnet 16 inserted into the magnet insertion hole 12 is pressed by the outer surface 11b of the hollow member 11 deformed along the through hole 23 in the tube expansion molding process. Fixed to the rotor magnetic core 24. The hollow member 11 hardly deforms due to a temperature change or the like. For this reason, even in an environment exposed to a refrigerant, the temporal change hardly occurs in the fixed state of the permanent magnet 16 with respect to the rotor magnetic core 24. Thereby, the permanent magnet rotor suitable for the permanent magnet electric motor driven in a refrigerant | coolant can be provided.

  Further, according to the method for manufacturing the permanent magnet rotor 20 according to the present embodiment, the inner surface 24a of the rotor magnetic core 24 including the through holes 23 functions as a mold, and therefore the rotor magnetic core 24 is used in the present embodiment. Even with such a complicated inner surface shape, the hollow member 11 can be deformed along this shape. Since the permanent magnet 16 is directly pressed by the hollow member 11, the pressure adjustment for deforming the hollow member 11 is easier than that of the permanent magnet rotor 10 described above, and the permanent magnet 16 is fixed more securely and firmly. Can do.

  The number of the through holes 23 and the position where the through holes 23 are formed are not particularly limited. For example, as a modification of the second embodiment, a rotor core 34 having a plurality of through holes 23 formed in the axial direction with respect to one magnet insertion hole 12 is provided, as in a permanent magnet rotor 30 shown in FIG. It may be an embodiment. According to the permanent magnet rotor 30, the permanent magnet 16 can be more firmly fixed with respect to the axial direction of the rotor magnetic core 34.

  Although not shown, a rotor core having a plurality of through holes 23 formed in the circumferential direction can also be used. In this case, the permanent magnet 16 can be more firmly fixed with respect to the circumferential direction of the rotor magnetic core. Or you may use the rotor magnetic core provided with the through-hole 23 which combined these arrangement | positioning suitably.

  By the way, the more complicated the inner surface shape of the rotor magnetic core, the more difficult the tube expansion of the hollow member 11 becomes. In particular, the thickness of the expanded hollow member 11 varies in thickness depending on which position on the inner surface of the rotor magnetic cores 24 and 34 is in contact. In such a case, the step of deforming the hollow member 11 may include a shaft pressing step of adjusting the thickness by compressing both ends of the hollow member 11 in the axial direction. Thereby, it becomes possible to make the thickness of the hollow member 11 to be deformed more uniform, and the hollow member 11 deformed along each through hole 23 can make the pressure for pressing the permanent magnet 16 uniform. .

  Further, as the number of through holes 23 increases, the rigidity of the rotor magnetic cores 24 and 34 decreases, and the mechanical strength of the permanent magnet rotors 20 and 30 may be excessively decreased. There is a similar risk when the through-hole 23 becomes large. If the mechanical strength is excessively reduced, the rotor magnetic cores 24 and 34 are deformed by the force applied to the rotor magnetic cores 24 and 34 when the permanent magnet rotors 20 and 30 rotate, and the permanent magnets 16 are not sufficiently fixed. There is a possibility. Therefore, the number of the through holes 23, the positions where the through holes 23 are formed, and the size of the through holes 23 depend on, for example, the size of the rotor magnetic cores 24 and 34, the performance of the permanent magnet motor to be employed, and the like. It is designed appropriately.

  Moreover, embodiment like the permanent magnet rotor 40 shown in FIG. 5 as another modification of 2nd embodiment may be sufficient. In the permanent magnet rotor 40, the through hole 43 is formed in a groove shape that communicates from the inner surface 44 a of the rotor magnetic core 44 to the magnet insertion hole 12 and also communicates in the axial direction of the rotor magnetic core 44. The circumferential width of the through-hole 43 is appropriately designed to such an extent that the mechanical strength of the permanent magnet rotor 40 does not decrease excessively.

  According to the permanent magnet rotor 40, the hollow member 11 is deformed along the through hole 44 formed in a groove shape communicating in the axial direction. For this reason, the deformed outer surface 11 b of the hollow member 11 covers a part of both ends of the permanent magnet 16 in the axial direction. Therefore, not only the permanent magnet 16 is pressed in the radial direction and fixed to the rotor magnetic core 44 by the hollow member 11 formed by the tube expansion, but the permanent magnet 16 can be fixed to the rotor magnetic core 44 also in the axial direction. it can.

  Moreover, according to the manufacturing method of the permanent magnet rotor 40, the radial and axial fixation of the permanent magnet 16 with respect to the rotor magnetic core 44 can be achieved in one step by performing the above-described tube expansion molding. As a result, the production efficiency of the permanent magnet rotor 40 can be improved, and the permanent magnet 16 can be more reliably and firmly fixed. Since the hollow member 11 and the rotor magnetic core 44 have refrigerant resistance, the fixed state does not deteriorate even in an environment exposed to the refrigerant.

  The third embodiment may be an embodiment such as the permanent magnet rotor 50 shown in FIG. The permanent magnet rotor 50 includes a hollow member 11, a holding member 57, a permanent magnet 56 disposed between the hollow member 11 and the holding member 57, and a rotor magnetic core 54. In the present embodiment, the hollow member 11, the permanent magnet 56, and the holding member 57 are integrated by tube expansion forming an internal pressure on the inner surface 11 a of the hollow member 11 and attached to the outer surface 54 b of the rotor magnetic core 54.

  The permanent magnet 56 is formed by annularly arranging plate-like magnets having magnetic pole faces having different polarities (N pole, S pole) facing each other and having a planar shape of a quarter arc. The permanent magnets 56 are arranged so that the polarities of the magnetic pole surfaces of the adjacent permanent magnets 56 are different. The size of the permanent magnet 56 is appropriately designed according to the size of the rotor magnetic core 54 and the like. As the permanent magnet 56, for example, a neodymium magnet having a high coercive force and not easily demagnetized is preferably used, but other types of magnets (for example, a ferrite magnet, a samarium cobalt magnet, etc.) may be used.

  The holding member 57 is an annular member provided to hold the permanent magnet 56. The inner diameter of the holding member 57 is substantially equal to the outer diameter of the annular permanent magnet 56. As the material of the holding member 57, a material having chemical strength and durability against temperature change (refrigerant resistance) in addition to normal mechanical strength is used.

  The rotor magnetic core 54 is a support member for supporting the hollow member 11, the permanent magnet 56, and the holding member 57 with the outer surface 54b. The rotor magnetic core 54 is formed in a cylindrical shape or a columnar shape, and the rotation shaft 101 is attached so that the rotation axis O coincides with a virtual straight line passing through the center.

  In the step of deforming the hollow member 11 (see FIG. 2B), the hollow member 11 to which the internal pressure is applied to the inner surface 11 a expands in the radial direction, and the outer surface 11 b comes into contact with the inner surface 56 a of the permanent magnet 56. When this internal pressure is further applied, the outer surface 11 b of the hollow member 11 presses the inner surface 56 a of the permanent magnet 56. Accordingly, the outer surface 56b of the permanent magnet 56 presses the inner surface 57a of the holding member 57, and the hollow member 11, the permanent magnet 56, and the holding member 57 are integrated. After these are integrated, they are fixed to the outer surface 54 b of the rotor magnetic core 54.

  According to the permanent magnet rotor 50 according to the present embodiment, the hollow member 11, the permanent magnet 16, and the holding member 57 are integrated in the tube expansion molding process. The hollow member 11 and the holding member 57 are hardly deformed by a temperature change or the like. For this reason, even in an environment exposed to a refrigerant, the temporal change hardly occurs in the fixed state of the integrated hollow member 11, permanent magnet 16, and holding member 57. Thereby, the permanent magnet rotor suitable for the permanent magnet electric motor driven in a refrigerant | coolant can be provided.

  In the manufacturing method of the permanent magnet rotors 10 to 50 according to the embodiment of the present invention, the tube forming of the hollow member 11 is performed by using a forming jig inserted into the hollow portion 11 c of the hollow member 11 along the inner surface 11 a of the hollow member 11. Thus, a molding method including a step of expanding the diameter of the hollow member 11 by passing in the axial direction may be used. As the forming jig, a mandrel having a tube expansion member at the tip can be used. For example, when the permanent magnet rotors 10 and 50 are manufactured, a mandrel having a tapered pipe expanding member may be used. Moreover, when manufacturing the permanent magnet rotor 20, 30, 40, in order to enable local diameter expansion with respect to the inner surface 11a, an open mandrel in which a part of the tube expansion member partially protrudes may be used. . Thereby, the hollow member 11 can be plastically deformed along the through holes 23 and 43 and the permanent magnet 16 can be pressed and fixed. The permanent magnet rotors 10 to 50 can be manufactured even if tube expansion including such steps is employed.

  It should be noted that 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.

  The permanent magnet rotor 10, 20, 30, 40 of the present invention is used in an IPM type (embedded magnet type) synchronous motor, and the permanent magnet rotor 50 is used in an SPM type (surface magnet type) synchronous motor. Since the electric motor using these permanent magnet rotors 10 to 50 has high reliability even in an environment exposed to a refrigerant, it is particularly suitable for a hermetic or semi-hermetic compressor used in an air conditioner or the like. Is preferred.

10, 20, 30, 40, 50: Permanent magnet rotor 11: Hollow member 11a: Inner surface of hollow member 11b: Outer surface of hollow member 12: Magnet insertion hole 14, 24, 34, 44, 54: Rotor magnetic core 14a, 24a, 44a: Inner surface of rotor magnetic core 16, 56: Permanent magnet 23, 43: Through hole 57: Holding member

Claims (4)

A tubular hollow member having an inner surface and an outer surface;
A cylindrical rotor magnetic core that is disposed so as to surround the outer surface of the hollow member, has a plurality of magnet insertion holes, and has a plurality of thin-walled portions with the shortest distance between the inner surface and each of the magnet insertion holes. When,
A plurality of permanent magnets inserted into each of the magnet insertion holes,
Each of the permanent magnets is
Each of the thin portions is pressed against the outer surface of the hollow member as a result of the hollow member being expanded by an internal pressure applied to the inner surface, and the rotor core is deformed in the radial direction. in a state of being sandwiched on the inner surface facing the該径direction, the permanent magnet rotor, characterized in Tei Rukoto is pressed and fixed to the rotor core. A tubular hollow member having an inner surface and an outer surface;
A cylindrical rotor magnetic core disposed so as to surround the outer surface of the hollow member, a plurality of magnet insertion holes being formed, and a plurality of through holes extending from the inner surface to each of the magnet insertion holes; ,
And a plurality of permanent magnets inserted into each of the magnet insertion holes,
Each of the permanent magnets is
The magnet insertion hole located on the outer side in the radial direction of the rotor magnetic core is pressed against the outer surface of the hollow member deformed along the through-hole as a result of the hollow member being expanded by an internal pressure applied to the inner surface. in a state pressed against the inner surface, the permanent magnet rotor characterized that you have been pressed and fixed to the rotor core. The permanent magnet rotor according to claim 2, wherein a plurality of the through holes are formed with respect to one magnet insertion hole. 4. The permanent magnet rotor according to claim 2, wherein the through hole is formed in a groove shape communicating in the axial direction of the rotor magnetic core. 5.

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