Manufacturing device of rotor, manufacturing method of rotor, and rotor

Abstract

A manufacturing device of a rotor (20) includes a magnetizing device (30). The magnetizing device (30) is configured to magnetize a permanent magnet (23) of the rotor from outside of the rotor. The rotor includes a rotor core (22) having a magnet accommodating hole (24), the permanent magnet is disposed in a state of being buried in the magnet accommodating hole, and has a convex return shape that protrudes toward a radially inner side. The magnetizing device includes a first yoke portion (32), a second yoke portion (34, 42), and a magnetizing coil (33, 35, 43). The first yoke portion has an opposing portion (32a) that opposes an outer peripheral surface (22a) of the rotor. The second yoke portion forms a magnetic path with the first yoke portion. The magnetizing coil (33, 35, 43) is disposed on the magnetic path of the first yoke portion and the second yoke portion. The magnetizing device causes a magnetizing magnetic flux to flow at least in an inside of the rotor between the first yoke portion and the second yoke portion that are in a diametrically opposite relationship with respect to the rotor, based on energization to the magnetizing coil, thereby magnetizing the permanent magnet.

Description

[0001] Citation of relevant applications

[0002] This application is based on Japanese Patent Application No. 2020-060871 filed on March 30, 2020 and Japanese Patent Application No. 2021-023504 filed on February 17, 2021, the contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to an apparatus for manufacturing an embedded magnet type rotor, a method for manufacturing a rotor, and a rotor for magnetizing a permanent magnet in an embedded state from the outside of the rotor. Background Technology

[0004] Conventionally, it is well known that rotary electric machines use rotors with embedded magnets (IPM type). In an IPM type rotor, the permanent magnet is embedded inside the rotor core, and reluctance torque is obtained in a portion of the rotor core that is radially outer from the permanent magnet. In such an IPM type rotor, the rotor core, which has unmagnetized permanent magnets in an embedded state, is magnetized from the outer diameter side using a magnetizing device (see, for example, Patent Document 1).

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2016-144322 Summary of the Invention

[0008] In addition, to improve the performance of the embedded magnet type rotor, the following measures are taken: the permanent magnet is shaped into a roughly V or U-shape, and the rotor core has a larger component in the radially outer part than the permanent magnet, thereby increasing the reluctance torque.

[0009] When it is desired to increase the radially outer portion of the rotor core, consider making the permanent magnet have a deep folded-back shape, such that the bent portion, which is the folded-back section of the permanent magnet, is located further radially inward. The closer the folded-back position of the permanent magnet is to the radially inward position, the further away the permanent magnet, especially the bent portion and its vicinity, is from the magnetizing device. Therefore, the bent portion or its vicinity, which is far from the magnetizing device, may not be able to generate sufficient magnetic force.

[0010] The purpose of this disclosure is to provide a rotor manufacturing apparatus, a rotor manufacturing method, and a rotor that has been magnetized by a high magnetic force to magnetize a permanent magnet in the embedded state of the rotor core.

[0011] In the first aspect of the present disclosure, a manufacturing device of a rotor includes a magnetizing device configured to magnetize a permanent magnet of the rotor from outside the rotor. The rotor includes a rotor core having a magnet accommodating hole. The permanent magnet is disposed in a state of being buried in the magnet accommodating hole and has a convex shape protruding toward an inner side in a radial direction. The magnetizing device includes a first yoke portion, a second yoke portion, and a magnetizing coil. The first yoke portion has an opposing portion opposite to an outer circumferential surface of the rotor. The second yoke portion forms a magnetic circuit with the first yoke portion and has an insertion portion inserted into a shaft insertion hole of the rotor before a rotating shaft is inserted into the shaft insertion hole or a connection portion magnetically connected to the rotating shaft inserted into the shaft insertion hole of the rotor. The magnetizing coil is disposed on the magnetic circuit of the first yoke portion and the second yoke portion. The magnetizing device is configured to cause a magnetizing magnetic flux to flow at least inside the rotor between the opposing portion of the first yoke portion and the insertion portion of the second yoke portion or the rotating shaft in a relationship opposite in the radial direction of the rotor based on energization of the magnetizing coil, thereby magnetizing the permanent magnet in the buried state.

[0012] In the second aspect of the present disclosure, a manufacturing method of a rotor uses a magnetizing device. The magnetizing device is configured to magnetize a permanent magnet of the rotor from outside the rotor. The rotor includes a rotor core having a magnet accommodating hole, and the permanent magnet is disposed in a state of being buried in the magnet accommodating hole and has a convex shape protruding toward an inner side in a radial direction. The magnetizing device includes a first yoke portion, a second yoke portion, and a magnetizing coil. The first yoke portion has an opposing portion opposite to an outer circumferential surface of the rotor. The second yoke portion forms a magnetic circuit with the first yoke portion and has an insertion portion inserted into a shaft insertion hole of the rotor before a rotating shaft is inserted into the shaft insertion hole or a connection portion magnetically connected to the rotating shaft inserted into the shaft insertion hole of the rotor. The magnetizing coil is disposed on the magnetic circuit of the first yoke portion and the second yoke portion. The manufacturing method is configured to cause a magnetizing magnetic flux to flow at least inside the rotor between the opposing portion of the first yoke portion and the insertion portion of the second yoke portion or the rotating shaft in a relationship opposite in the radial direction of the rotor based on energization of the magnetizing coil, thereby magnetizing the permanent magnet in the buried state.

[0013] According to the manufacturing device of the rotor and the manufacturing method of the rotor described above, when magnetization of the permanent magnet in the buried state in the rotor is performed from the outside using a magnetization device, magnetization is performed in such a manner that the magnetization magnetic flux flows at least inside the rotor between the opposing portions of the first yoke portions in the diametrically opposite relationship with respect to the rotor and the insertion portions of the second yoke portions inserted into the shaft insertion holes before the rotation shafts are inserted or the rotation shafts inserted into the shaft insertion holes of the rotor magnetically coupled to the second yoke portions. That is, although the bent portions of the permanent magnet in the convex fold shape protruding to the inside in the radial direction or the vicinity of the bent portions are positions where the magnetization magnetic flux is difficult to reach in the magnetization performed from the outside diameter side as in the past, by using the above-described magnetization method, sufficient magnetization magnetic flux can be supplied to the bent portions of the permanent magnet or the vicinity of the bent portions. Thus, magnetization can be performed with sufficient magnetic force in the entire range of the permanent magnet.

[0014] In the third aspect of the present disclosure, a rotor includes a rotor core and a permanent magnet. The rotor core has a magnet housing hole, and the permanent magnet is disposed in a state of being buried in the magnet housing hole and has a convex fold shape protruding to the inside in a radial direction. The rotor is configured to perform magnetization of the permanent magnet in the buried state from the outside using a magnetization device. When an interval between an extension line of an inner side surface of the permanent magnet of the fold shape in an outer peripheral surface of the rotor core and an extension line of an outer side surface of the permanent magnet is set as a pole pitch, and a distance from the outer peripheral surface of the rotor core to an inner side surface of the bent portion of the permanent magnet on a circumferential center line of the permanent magnet is set as a buried depth, the permanent magnet has a deep fold shape in which the buried depth is greater than the pole pitch. In a case where an inflection point at which a change in magnetic field strength generated by the magnetization of the permanent magnet becomes gentle is set as a desired lower limit value, the permanent magnet is magnetized in a manner in which a portion of the permanent magnet in which the magnetization is performed using a magnetic field strength exceeding the desired lower limit value is more than 90%.

[0015] In the rotor having the permanent magnet in the deep fold shape in which the buried depth is greater than the pole pitch, although the bent portion of the permanent magnet or the vicinity of the bent portion is a position where the magnetization magnetic flux is difficult to reach, by using the manufacturing device of the rotor and the manufacturing method of the rotor described above, magnetization can be performed with sufficient magnetic force in the entire range of the permanent magnet. In this case, if an inflection point at which a change in magnetic field strength generated by the magnetization of the permanent magnet becomes gentle is set as a desired lower limit value, in the permanent magnet of the rotor, the magnetization can be performed in a manner in which a portion in which the magnetization is performed using a magnetic field strength exceeding the desired lower limit value is more than 90% (see Figure 10 BRIEF DESCRIPTION OF DRAWINGS

[0016] The above objects and other objects, features and advantages of the present disclosure will become more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0017] Figure 1 ​is a configuration diagram of a rotary electric machine having an interior magnet type rotor.

[0018] Figure 2 is a configuration diagram of a rotor.

[0019] Figure 3 is a cross-sectional view of a rotor.

[0020] Figure 4 is an explanatory diagram for explaining a configuration of a magnetizing device of an embodiment.

[0021] Figure 5 is an explanatory diagram for explaining a configuration of a magnetizing device of Figure 4 .

[0022] Figure 6 is an explanatory diagram for explaining a configuration of a magnetizing device of Figure 4 .

[0023] Figure 7 is an explanatory diagram for explaining a magnetizing method of a magnetizing device of Figure 4 .

[0024] Figure 8 is an explanatory diagram for explaining a magnetizing method of a magnetizing device of Figure 4 .

[0025] Figure 9 is an explanatory diagram for explaining a permanent magnet magnetized by a magnetizing device of Figure 4 .

[0026] Figure 10 is an explanatory diagram for explaining a permanent magnet magnetized by a magnetizing device of Figure 4 .

[0027] Figure 11 is an explanatory diagram for explaining a configuration of a magnetizing device of a modification example.

[0028] Figure 12 is an explanatory diagram for explaining a configuration of a magnetizing device of a modification example.

[0029] Figure 13 is an explanatory diagram for explaining a configuration and a magnetizing method of a magnetizing device of a modification example. DETAILED DESCRIPTION

[0030] Hereinafter, an embodiment of a rotor, a manufacturing device of a rotor, a manufacturing method of a rotor, and a rotor will be described.

[0031] Figure 1 The rotary electric machine M of the present embodiment shown in FIG. 1 is a brushless motor of an interior magnet type. The rotary electric machine M includes a substantially circular ring-shaped stator 10 and a substantially cylindrical rotor 20 rotatably disposed in a radially inner side space of the stator 10.

[0032] The stator 10 includes a substantially annular stator core 11. The stator core 11 is composed of a magnetic metal material, for example, by stacking a plurality of electromagnetic steel sheets in the axial direction. In the present embodiment, the stator core 11 has twelve pole teeth 12 extending toward the radial inner side and arranged at equal intervals in the circumferential direction. Each of the pole teeth 12 is in the same shape as each other. The front end portion, i.e., the radial inner side end portion, of the pole tooth 12 is in a substantially T shape, and the front end face 12a is in a circular arc shape along the outer peripheral surface of the rotor 20. The winding 13 is wound on the pole tooth 12 in a concentrated winding manner. The winding 13 is a three-phase connection, and functions as a U phase, a V phase, and a W phase, respectively, as shown. Further, when power is supplied to the winding 13, a rotating magnetic field for driving the rotor 20 to rotate is generated in the stator 10. In such a stator 10, the outer peripheral surface of the stator core 11 is fixed to the inner peripheral surface of the housing 14. Figure 1

[0033] In the present embodiment, the rotor 20 includes a rotating shaft 21, a substantially cylindrical rotor core 22 in which the rotating shaft 21 is inserted in the central portion, and eight permanent magnets 23 in a form of being buried in the inside of the rotor core 22. The rotor core 22 is composed of a magnetic metal material, for example, by stacking a plurality of electromagnetic steel sheets in the axial direction. The rotor 20 is configured to be rotatable with respect to the stator 10 by supporting the rotating shaft 21 to an omitted bearing provided to the housing 14.

[0034] The rotor core 22 has a magnet accommodating hole 24 for accommodating the permanent magnet 23. In the present embodiment, eight magnet accommodating holes 24 are provided at equal intervals along the circumferential direction of the rotor core 22. Each of the magnet accommodating holes 24 is in a substantially V-shaped shape of a convex substantially V shape protruding toward the radial inner side, and is in the same shape as each other. In addition, the magnet accommodating hole 24 is provided in the entire range of the axial direction of the rotor core 22.

[0035] Here, the permanent magnet 23 of the present embodiment is composed of a bonded magnet that is formed by hardening a magnet material after mixing a magnet powder with a resin. That is, the permanent magnet 23 is composed by providing the magnet accommodating hole 24 of the rotor core 22 as a molding die, filling the magnet material before hardening into the magnet accommodating hole 24 without a gap by injection molding, and hardening in the magnet accommodating hole 24 after the filling. Therefore, the hole shape of the magnet accommodating hole 24 becomes the outer shape of the permanent magnet 23. As the magnet powder used for the permanent magnet 23 of the present embodiment, for example, a samarium iron nitride (SmFeN) type magnet is used, but other rare earth magnets or the like can be used.

[0036] The permanent magnet 23 is in a substantially V-shaped shape of a convex substantially V shape protruding toward the radial inner side. In detail, as shown in FIG. 2, the permanent magnet 23 is in a substantially V-shaped shape of a convex substantially V shape protruding toward the radial inner side, and the outer shape of the permanent magnet 23 is in a substantially V-shaped shape of a convex substantially V shape protruding toward the radial inner side. Figure 2 ​As shown, the permanent magnet 23 has a shape in which the radially inner ends of a pair of straight sections 23a are connected to each other by a curved section 23b. The radially outer end 23c of the straight section 23a is located near the outer peripheral surface 22a of the rotor core 22. The thickness Wm of the permanent magnet 23 is set to be constant at any point in the V-shaped path including the pair of straight sections 23a and the curved section 23b. The permanent magnet 23 is linearly symmetrical with respect to its own circumferential center line Ls passing through the shaft center O1 of the rotor 20, and is close to the magnetic pole boundary line Ld passing through the shaft center O1 of the rotor 20 between adjacent permanent magnets 23. The angle between adjacent magnetic pole boundary lines Ld, that is, the magnetic pole opening angle θm of the rotor magnetic pole section 26 including the permanent magnet 23, is an electrical angle of 180°.

[0037] Furthermore, when the distance between the extended lines of the inner surfaces of the straight portions 23a of the permanent magnets 23 in the outer peripheral surface 22a of the rotor core 22 is defined as the pole spacing Lp, and the distance from the outer peripheral surface 22a of the rotor core 22 to the inner surface of the curved portion 23b of the permanent magnet 23 on the circumferential center line Ls of the permanent magnet 23 is defined as the embedment depth Lm, the permanent magnets 23 in this embodiment adopt a deep folded shape with an embedment depth Lm greater than the pole spacing Lp. That is, as... Figure 2 and Figure 3 As shown, in this embodiment, the permanent magnet 23 has a deep, folded-back shape with its own curved portion 23b located near the center of the rotor core 22, close to the radially inward side of the shaft insertion hole 22b into which the rotating shaft 21 is inserted. Furthermore, the permanent magnet 23 is disposed within the entire axial direction of the rotor core 22.

[0038] The permanent magnet 23 hardened within the magnet receiving hole 24 of the rotor core 22 is used. Figure 4 The magnetizing device 30 shown above magnetizes the rotor core 22 from the outside, starting from an unmagnetized state, so that it functions as a regular magnet. The magnetizing device 30 and the magnetizing method using it will be described in detail later. In this embodiment, eight permanent magnets 23 are arranged circumferentially on the rotor core 22, and magnetization is performed by alternating different polarities in the circumferential direction. Furthermore, each permanent magnet 23 is magnetized in its own thickness direction.

[0039] The portion of the rotor core 22 that is radially outer than the permanent magnet 23 and opposite to the stator 10 functions as the outer core portion 25 for obtaining reluctance torque. Furthermore, the rotor 20 of this embodiment includes eight-pole rotor pole portions 26. In the rotor 20, each rotor pole portion 26 includes a permanent magnet 23 and an outer core portion 25 surrounded by the approximately V-shape of each permanent magnet 23. Figure 1 As shown, the rotor pole section 26 alternately functions as the N pole and the S pole in the circumferential direction. In the rotor 20 having such a rotor pole section 26, appropriate magnetic torque and reluctance torque can be obtained.

[0040] Next, a manufacturing device of the rotor 20 including the magnetizing device 30 including the permanent magnet 23 and a magnetizing method of the permanent magnet 23 using the magnetizing device 30, and a manufacturing method of the rotor 20 will be described.

[0041] [Structure of magnetizing device]

[0042] Use Figure 4 , Figure 5 and Figure 6 The magnetizing device 30 of the present embodiment will be described. In addition, in the drawings, Figures 4 to 6 , the hatching of the cross-sectional portions is appropriately omitted. In addition, in the drawings, Figure 6 , the rotor 20 is illustrated as a cross section, and the magnetizing device 30 is illustrated as an end surface.

[0043] As shown in Figures 4 to 6 , the magnetizing device 30 includes a device main body portion (stationary portion) 31 and a device upper side portion (movable portion) 41, and the device upper side portion 41 is capable of contacting and separating from the device main body portion 31 in order to be able to set and take out the rotor 20 which is a magnetization target. Furthermore, the arrangement and the manner of operation of the device main body portion 31 and the device upper side portion 41 are one example, and can be appropriately changed.

[0044] The device main body portion 31 integrally includes a main magnetizing portion 30a and a lower side auxiliary magnetizing portion 30b. The main magnetizing portion 30a includes an outer diameter side main yoke portion 32 (first yoke portion) made of a magnetic metal and a main magnetizing coil 33 for magnetization (magnetizing coil, first coil for magnetization). The outer diameter side main yoke portion 32 has eight magnetizing relative protrusions (relative portions) 32a which are provided corresponding to each rotor magnetic pole portion 26 of the rotor 20 provided to the magnetizing device 30. The radially inner side end portion, that is, the front end portion 32al of each magnetizing relative protrusion 32a becomes a positional relationship in which it is in close proximity to the outer peripheral surface 22a of the rotor 20 (rotor core 22) in the radial direction. On each magnetizing relative protrusion 32a, the main magnetizing coil 33 is wound in a manner in which the winding axis is directed in the radial direction. The radially outer peripheral portion of the outer diameter side main yoke portion 32 is a ring-shaped linking portion 32b (omission of illustration of the ring shape of the ring-shaped linking portion 32b) which integrally links each magnetizing relative protrusion 32a which is provided at an equal interval in the circumferential direction.

[0045] The lower-side auxiliary magnetizing portion 30b includes a lower-side auxiliary yoke portion (second yoke portion) 34 made of a magnetic metal and a lower-side auxiliary magnetizing coil (magnetizing coil, second magnetizing coil) 35. The lower-side auxiliary yoke portion 34 includes eight lower-side link portions 34a provided in correspondence with the respective magnetizing opposed projections 32a and one lower-side collection portion 34b that collects the respective lower-side link portions 34a. One end of each of the lower-side link portions 34a is integrally linked with a lower surface portion of the annular link portion 32b of the outer-diameter-side main yoke portion 32, respectively. Each of the lower-side link portions 34a is shaped so as to avoid the magnetizing main coil 33 and the like and to meander toward the lower side in the axial direction, and the other end of each of the lower-side link portions 34a is integrally linked with the lower-side collection portion 34b, respectively.

[0046] The lower-side collection portion 34b is located on the lower side of the rotor 20 provided in the magnetizing device 30 and is shaped like a column along the axial direction of the rotor 20. The rotor 20 abuts against a central portion of an upper surface of the lower-side collection portion 34b. That is, the lower-side collection portion 34b has an abutting portion 34c on which the rotor 20 is placed, and a lower-side insertion protrusion (insertion site, insertion protrusion) 34d that is inserted into the axial insertion hole 22b of the central portion of the rotor 20 is provided at a position that is more inward than the abutting portion 34c.

[0047] In addition, the magnetizing lower-side auxiliary coil 35 is wound around the lower-side collection portion 34b in such a manner that the winding axis is directed in the axial direction. A lower-side first restriction member (restriction member) 36 made of a non-magnetic metal and shaped like a cylinder is attached to the outer peripheral side of the magnetizing lower-side auxiliary coil 35, and a lower-side second restriction member (restriction member) 37 made of a non-magnetic metal and shaped like a plate is fixed to the lower-side collection portion 34b and the like on the upper side in the axial direction of the magnetizing lower-side auxiliary coil 35. Each of the upper side surfaces of the lower-side second restriction member 37 and the abutting portion 34c is, for example, coplanar. Each of the restriction members 36 and 37 is, for example, made of SUS. Furthermore, each of the restriction members 36 and 37 is provided in order to reduce swelling or winding loosening of the magnetizing lower-side auxiliary coil 35 at the time of energization at the time of magnetization.

[0048] On the other hand, the device upper side portion 41, which operates in contact with and separation from the device main body portion 31, includes only an upper side auxiliary magnetomotive portion 30c. The upper side auxiliary magnetomotive portion 30c includes an upper side auxiliary yoke portion (second yoke portion) 42 made of a magnetic metal and an upper side auxiliary magnetomotive coil (magnetomotive coil, second magnetomotive coil) 43. The upper side auxiliary yoke portion 42 has a structure symmetrical to the lower side auxiliary yoke portion 34 in the up-and-down direction, includes eight upper side link portions 42a provided corresponding to the respective magnetomotive opposing protrusions 32a and one upper side collection portion 42b that collects the respective upper side link portions 42a. One end of each of the upper side link portions 42a is configured to be able to abut against the upper surface portion of the annular link portion 32b of the outer diameter side main yoke portion 32. Each of the upper side link portions 42a has a shape that avoids the magnetomotive main coil 33 and the like and detours to the upper side in the axial direction, and the other end of each of the upper side link portions 42a is linked to the upper side collection portion 42b integrally. The upper side auxiliary yoke portion 42 has a structure in which the respective upper side link portions 42a are linked to the upper side collection portion 42b integrally.

[0049] The upper side collection portion 42b is located on the upper side of the rotor 20 provided in the magnetomotive device 30 and has a columnar shape along the axial direction of the rotor 20. The upper side collection portion 42b has an abutting portion 42c that abuts against the rotor 20 at a central portion of the lower surface thereof, and an upper side insertion protrusion (insertion portion, insertion protrusion) 42d that is inserted into the axial insertion hole 22b of the central portion of the rotor 20 from the upper side is provided at a position inside the abutting portion 42c.

[0050] In addition, the upper side auxiliary magnetomotive coil 43 is wound around the winding shaft in the axial direction on the upper side collection portion 42b. A first upper side restriction member (restriction member) 44 made of a non-magnetic metal and having a cylindrical shape is attached to the outer peripheral side of the upper side auxiliary magnetomotive coil 43, and a second upper side restriction member (restriction member) 45 made of a non-magnetic metal and having a plate shape is provided on the axial lower side of the upper side auxiliary magnetomotive coil 43. The second upper side restriction member 45 is fixed to the upper side collection portion 42b and the like. Each of the lower side surfaces of the abutting portion 42c and the second upper side restriction member 45 is, for example, coplanar. Each of the restriction members 44 and 45 is, for example, made of SUS. Furthermore, each of the restriction members 44 and 45 is provided to reduce swelling or winding looseness of the upper side auxiliary magnetomotive coil 43 at the time of energization at the time of magnetomotive. In addition, the second upper side restriction member 45 also reduces winding looseness and the like due to the weight of the upper side auxiliary magnetomotive coil 43.

[0051] In the magnetizing device 30 of this embodiment, as the magnetizing operation of the main magnetizing section 30a, magnetization is performed by causing magnetizing flux to flow through the interior of the rotor 20 between adjacent magnetizing protrusions 32a in the circumferential direction. Furthermore, the main magnetizing section 30a and each of the auxiliary magnetizing sections 30b and 30c operate in coordination, thereby enabling magnetization by force to flow magnetizing flux even on the inner diameter side of the rotor 20, which is difficult to reach using only the main magnetizing section 30a. That is, in the magnetizing device 30 of this embodiment, magnetization is configured to effectively perform magnetization of the permanent magnet 23, particularly the curved portion 23b located radially inward and near the curved portion 23b, which is far from the main magnetizing section 30a.

[0052] [Method for magnetizing permanent magnets using a magnetizing device]

[0053] Using the magnetizing device 30 with the above structure, firstly, a rotor 20 having an unmagnetized permanent magnet 23 is placed in the magnetizing device 30. Furthermore, the rotor 20 to be magnetized is in the state before the rotating shaft 21 is inserted, and the shaft insertion hole 22b is in the open state.

[0054] like Figure 6 As shown, with the upper part 41 of the device moved upwards away from the main body 31, the rotor 20, which has an unmagnetized permanent magnet 23, is placed on the upper surface of the lower assembly part 34b of the main body 31. At this time, the lower insertion protrusion 34d is inserted into the shaft insertion hole 22b of the rotor 20. When the rotor 20 is placed on the main body 31, as... Figure 4 and Figure 5 As shown, the upper part 41 of the device is lowered axially, so that the upper insertion protrusion 42d is inserted into the shaft insertion hole 22b of the rotor 20. Furthermore, the lowering of the upper part 41 continues until one end of the upper connecting part 42a of the upper auxiliary yoke 42 abuts against the upper surface of the outer diameter main yoke 32. That is, the upper auxiliary yoke 42 and the outer diameter main yoke 32 are magnetically connected, thereby achieving a state in which magnetic flux flows smoothly between the upper auxiliary yoke 42 and the outer diameter main yoke 32.

[0055] Next, for the unmagnetized permanent magnets 23 of the rotor 20, magnetization is performed in two steps in this embodiment. In this embodiment, for example, the S pole is magnetized first, followed by the N pole magnetization. This magnetization sequence is one example, but the magnetization sequence can also be reversed.

[0056] When the S-pole is magnetized, the S-pole magnetization is performed on the eight unmagnetized permanent magnets 23 arranged circumferentially on the rotor 20, with every other permanent magnet 23 placed as a candidate for S-pole magnetization. That is, from... Figure 5The magnetization control device 50 shown energizes the main magnetizing coil 33 and auxiliary coils 35, 43, which are installed at intervals along the circumferential direction on the magnetizing protrusions 32a for magnetizing the S pole. Thus, as... Figure 7 As shown, inside the rotor 20, magnetizing flux flows from the magnetizing opposing protrusions 32a of the main yoke 32 on the outer diameter side toward the insertion protrusions 34d and 42d of the auxiliary yokes 34 and 42.

[0057] At this time, since the opposing protrusions 32a and the insertion protrusions 34d and 42d that are magnetically connected to each other are positioned relative to each other on the radially outer and radially inner sides of the rotor 20, the magnetizing flux traveling inside the rotor 20 within the entire range from the radially outer to the radially inner side of the rotor 20 increases. In addition, by providing auxiliary coils 35 and 43 and energizing them in a manner that cooperates with the main magnetizing coil 33, a greater force can be applied to the flow of the magnetizing flux, and the ideal flux flow can be maintained more effectively.

[0058] When N-pole magnetization is performed, the remaining permanent magnets 23 of the rotor 20, which are placed at every other interval, are magnetized to N-pole. That is, the magnetization control device 50 energizes the main magnetizing coil 33 and auxiliary coils 35, 43, which are installed at every other interval in the circumferential direction for N-pole magnetization, in the opposite direction to S-pole magnetization. Thus, as... Figure 8 As shown, inside the rotor 20, a magnetizing flux flows from the insertion protrusions 34d and 42d of each auxiliary yoke 34 and 42 toward the magnetizing protrusions 32a of the main yoke 32 on the outer diameter side, in the opposite direction to the magnetization of the S pole.

[0059] Similarly, in the case of magnetization at the N pole, since the opposing protrusions 32a and the insertion protrusions 34d and 42d that are magnetically connected to each other are positioned relative to each other on the radially outer and radially inner sides of the rotor 20, the magnetizing flux traveling inside the rotor 20 within the entire range from the radially inner to the radially outer side of the rotor 20 increases. Furthermore, by providing auxiliary coils 35 and 43 and energizing them together with the main magnetizing coil 33, a greater force can be applied to the flow of the magnetizing flux at the N pole, and the ideal flux flow can be maintained more effectively.

[0060] Therefore, even with a permanent magnet 23 of this embodiment, which has a roughly V-shaped folded-back shape, where the folded-back portion, i.e., the bent portion 23b, is located near the radially inner side, magnetization can be effectively performed on the bent portion 23b and the area near the bent portion 23b, which is far from the main magnetizing portion 30a. This is especially significant when a deep folded-back shape, as in the permanent magnet 23 of this embodiment, is used, where the embedment depth Lm is greater than the pole spacing Lp.

[0061] Assuming that, in the conventional general magnetization method in which magnetization is performed using only the outer-diameter-side main magnetizing portion 30a without using each auxiliary magnetizing portion 30b, 30c, the coercive force of the magnetization magnetic flux passing through the radially inner side of the rotor 20 is also weak, the magnetic force of the bent portion 23b of the permanent magnet 23 and the vicinity of the bent portion 23b is weak. In the case of the permanent magnet 23 having a deep folded shape as in the present embodiment, it can be predicted that the magnetic force of the bent portion 23b and the vicinity thereof becomes weaker.

[0062] As Figure 9 shown, in the case where the bent portion 23b of the permanent magnet 23 located on the radially inner side of the rotor 20 is considered to be an oblong portion that is relatively long in the axial direction in a side view of the permanent magnet 23, the magnetic force of the central portion 23x in the up-down direction of the oblong portion easily becomes the weakest. In this regard, by using the magnetization method of the present embodiment, even in the central portion 23x in the up-down direction, magnetization can be performed with a magnetic field strength exceeding the desired lower limit value. The upper portion, the lower portion, and the straight portion 23a of the central portion 23x in the up-down direction of the bent portion 23b can be magnetized with a more sufficient magnetic field strength. In addition, as Figure 10 shown, in the case where an inflection point at which the change in the magnetic field strength generated by the magnetization of the permanent magnet 23 becomes gentle is set as the desired lower limit value, the portion where magnetization is performed with a magnetic field strength exceeding the desired lower limit value is about 95% of more than 90%, and magnetization can be performed with a sufficient magnetic force in the entire range of the permanent magnet 23.

[0063] The effects of the present embodiment will be described.

[0064] (1) When the magnetization device 30 of the present embodiment is used to externally magnetize the permanent magnet 23 in a buried state in which it is buried in the rotor 20, the following magnetization is performed: the magnetization magnetic flux also flows inside the rotor 20 between the magnetization-use opposing protrusions 32a of the outer-diameter-side main yoke portion 32 and the insertion protrusions 34d, 42d of each auxiliary yoke portion 34, 42 inserted into the shaft insertion hole 22b before the shaft 21 is inserted. That is, in the permanent magnet 23 having a convex folded shape that protrudes toward the radially inner side as in the present embodiment, particularly the bent portion 23b and the vicinity of the bent portion 23b are in a position where the magnetization magnetic flux is difficult to reach in the conventional general magnetization performed from the outer-diameter side. By using the magnetization method as in the present embodiment, sufficient magnetization magnetic flux can be supplied to the bent portion 23b of the permanent magnet 23 or the vicinity of the bent portion 23b. Thereby, magnetization can be performed with sufficient magnetic force in the entire range of the permanent magnet 23.

[0065] (2) The magnetization main coils 33 wound on the opposite portions of the outer-diameter side main yoke portion 32 and the magnetization auxiliary coils 35, 43 wound on the insertion protrusions 34d, 42d near the collection portions 34b, 42b of the auxiliary yoke portions 34, 42 are cooperatively operated to supply the magnetization magnetic flux. That is, by applying the energization operation of the auxiliary coils 35, 43 near the position of the bent portion 23b of the permanent magnet 23, the supply of the magnetization magnetic flux can be effectively maintained in the bent portion 23b of the permanent magnet 23 or near the bent portion 23b. Thus, the magnetization can be more reliably performed with sufficient magnetic force in the entire range of the permanent magnet 23.

[0066] (3) The magnetization auxiliary coils 35, 43 are commonly provided for different poles including the rotor pole portion 26 of the permanent magnet 23, and the energization mode is switched for each magnetized pole of the permanent magnet 23, thereby switching the direction of the magnetization magnetic flux. Thus, the number of the auxiliary coils 35, 43 in the magnetization device 30 can be constituted with as few as possible. Further, since the insertion protrusions 34d, 42d inserted into the shaft insertion hole 22b of the rotor 20 are also common, the insertion protrusions 34d, 42d can be constituted as large as possible in the shaft insertion hole 22b, and the magnetic resistance can be reduced as much as possible.

[0067] (4) The upper auxiliary yoke portion 42, the lower auxiliary yoke portion 34, the upper magnetization auxiliary coil 43, and the lower magnetization auxiliary coil 35 are symmetrically provided in a pair at one side and the other side (in this embodiment, the upper side and the lower side) of the axial direction of the rotor 20 as the magnetization object. Thus, the symmetric magnetization magnetic flux can be supplied in the axial direction of the rotor 20, and the magnetization can be performed with good balance in the axial direction of the permanent magnet 23.

[0068] (5) The permanent magnet 23 of this embodiment has a deep shape with a depth Lm larger than the pole pitch Lp. The magnetization can be performed in such a manner that, in the permanent magnet 23, the portion in which the magnetization is performed with the magnetic field strength exceeding the desired lower limit value exceeds 90% when the inflection point at which the change in the magnetic field strength generated by the magnetization becomes gentle is set as the desired lower limit value. That is, even in the magnetization performed from the outside of the rotor 20, the rotor 20 including the permanent magnet 23 having the bent portion 23b and performing the magnetization with high magnetic force can be constituted.

[0069] This embodiment can be changed and implemented as follows. This embodiment and the following modified examples can be combined with each other and implemented within a range in which the technical contradiction does not occur.

[0070] • In the insertion protrusions 34d, 42d of the auxiliary yoke portions 34, 42, as Figure 6As shown by a broken line and a symbol in parentheses, a tapered portion 34x, 42x can be provided at the front end portion thereof, and each insertion protrusion 34d, 42d can be provided in a thin shape. In this case, each insertion protrusion 34d, 42d is easily inserted into the shaft insertion hole 22b of the rotor 20. In addition, a tapered portion 22x, which has an opening in a flared shape, is provided in the shaft insertion hole 22b of the rotor 20, and each insertion protrusion 34d, 42d is easily inserted into the shaft insertion hole 22b.

[0071] • The same insertion protrusions 34d, 42d are provided in each auxiliary yoke portion 34, 42, but the protruding lengths of the insertion protrusions 34d, 42d can be different. For example, as shown in Figure 12 If the protruding length LI of the lower insertion protrusion 34d is longer than the protruding length L2 of the upper insertion protrusion 42d, the stability of the arrangement of the rotor 20 inserted into the lower insertion protrusion 34d and supported thereby is expected to be improved, and the like. In other words, if the protruding length L2 of the upper insertion protrusion 42d is shorter than the protruding length LI of the lower insertion protrusion 34d, the possibility of the upper insertion protrusion 42d contacting the surrounding members is reduced, and the movement of the device upper portion 41, which is a movable portion, relative to the device main portion 31, which is a stationary portion, becomes easier. In addition, the protruding length L2 of the upper insertion protrusion 42d can be zero, and only the lower insertion protrusion 34d can be provided, and the shaft of the rotor 20 can be inserted from one end to the other end. In addition, the upper insertion protrusion 42d can be provided alone.

[0072] • The insertion protrusions 34d, 42d are provided in each auxiliary yoke portion 34, 42, and each insertion protrusion 34d, 42d is inserted into the shaft insertion hole 22b of the rotor 20 before the rotating shaft 21 is inserted, and the magnetization is performed, but for example, as shown in Figure 11 the rotating shaft 21 itself inserted into the shaft insertion hole 22b of the rotor 20 can be used as a part of the magnetic circuit, and the magnetization of the permanent magnet 23 can be performed in a state in which the rotating shaft 21 is attached to the rotor 20. In this modification, a lower linking recess (linking portion) 34e is provided in the lower collective portion 34b of the lower auxiliary yoke portion 34, and an upper linking recess (linking portion) 42e is provided in the upper collective portion 42b of the upper auxiliary yoke portion 42. Moreover, the lower end portion and the upper end portion of the rotating shaft 21, which is in a state in which it is attached to the rotor 20, which is the magnetization target, are inserted into and magnetically linked to each linking recess 34e, 42e, and the magnetization of the permanent magnet 23 is performed in such a manner that the magnetization-use opposing protrusion 32a of the outer diameter side main yoke portion 32 and the rotating shaft 21 are opposed to each other in the radial direction of the rotor 20, and the magnetization magnetic flux flows between these. In addition, in this modification, it can be applied to a case in which the rotating shaft 21 is made of a magnetic metal.

[0073] • The deformation or movement of the magnetizing auxiliary coils 35, 43 is restricted by the non-magnetic metal-made restriction members 36, 37, 44, 45 provided around the magnetizing auxiliary coils 35, 43, but the restriction method is not limited thereto. For example Figure 12 As shown in FIG. 6, the periphery of each of the magnetizing auxiliary coils 35, 43 can be covered and cured with a thermosetting resin such as an epoxy resin to form a coil holding portion (restriction member) 38, 46, thereby restricting the deformation or movement of each of the magnetizing auxiliary coils 35, 43. Even in this case, reduction of the deformation or loosening of the winding of each of the magnetizing auxiliary coils 35, 43 at the time of energization can be achieved. In addition, since the area of the resin of the coil holding portion 38, 46 in contact with each of the magnetizing auxiliary coils 35, 43 increases, it is expected that the heat absorption from each of the magnetizing auxiliary coils 35, 43 to the coil holding portion 38, 46 becomes more efficient.

[0074] Further, in the case of Figure 12 In the case where the restriction members 36, 37, 44, 45 are further installed outside the coil holding portions 38, 46, the deformation or movement of each of the magnetizing auxiliary coils 35, 43 can be more reliably restricted. In this case, since each of the magnetizing auxiliary coils 35, 43 is covered by the coil holding portions 38, 46, the possibility that each of the metal-made restriction members 36, 37, 44, 45 is damaged by contact with each of the magnetizing auxiliary coils 35, 43 at the time of installation of each of the restriction members 36, 37, 44, 45 can be reduced. In the case where the coil holding portions 38, 46 are provided, any one of the installation of each of the restriction members 36, 37, 44, 45 can be omitted, and all of the restriction members 36, 37, 44, 45 can be omitted.

[0075] In addition, not only each of the magnetizing auxiliary coils 35, 43 but also the magnetizing main coil 33 can be covered and cured with a thermosetting resin such as an epoxy resin to form a coil holding portion (restriction member) 39, thereby restricting the deformation or movement of the magnetizing main coil 33. In this case, reduction of the deformation or loosening of the winding of the magnetizing main coil 33 at the time of energization can be achieved.

[0076] • The upper auxiliary yoke portion 42 and the lower auxiliary yoke portion 34 and the magnetizing upper auxiliary coil 43 and the magnetizing lower auxiliary coil 35 are symmetrically provided on both sides of the rotor 20 in the axial direction of the rotor 20, but can be provided on only one side. In this case, as described above, it is desirable that the insertion protrusions 34d, 42d are provided so as to be inserted from one end to the other end of the rotor 20.

[0077] A main magnetizing coil 33 is provided on the opposing protrusion 32a of the main yoke 32 on the outer diameter side, and auxiliary magnetizing coils 35 and 43 are provided on the agglomeration portions 34b and 42b of each auxiliary magnetizing yoke 34 and 42. However, the arrangement of the magnetizing coils is not limited to this. For example, for each auxiliary coil 35 and 43, the auxiliary coils can be wound and provided separately on each connecting portion 34a and 42a of each auxiliary yoke 34 and 42. In this case, each agglomeration portion 34b and 42b and each insertion protrusion 34d and 42d can be shared as in the above embodiment, but the magnetic circuit can also be made independent within the range from each connecting portion 34a and 42a to each insertion protrusion 34d and 42d. The position of the main coil 33 can also be appropriately changed to a position other than the opposing protrusion 32a. Alternatively, the magnetizing coils can be shared without separating the main coil 33 and each auxiliary coil 35 and 43.

[0078] ·exist Figure 4 In this process, the rotor 20 to be magnetized is one, but multiple rotors 20 can also be magnetized simultaneously. For example... Figure 13 As shown, four rotors 20 can also be stacked axially and magnetized simultaneously. This allows for increased rotor productivity by magnetizing multiple rotors 20 at the same time.

[0079] Furthermore, regarding the rotor mounting space 30x between the main body 31 and the upper side 41 of the magnetizing device 30, for example... Figure 13 As shown, when a gap is generated axially outside the rotor 20 due to the axial length or number of rotors 20 that are magnetizing objects, a spacer 51 is provided to fill the gap. Figure 13 In this configuration, spacers 51 are provided together between every two rotors 20. It is ideal to make the spacers 51 from the same magnetic metal material as the rotor core 22, as this has less impact on the flow of magnetic flux, but other magnetic metal materials can also be used.

[0080] Furthermore, in the aforementioned magnetizing device 30, the distribution of the magnetic force of the permanent magnet 23 when magnetizing a rotor 20 is as follows: Figure 9 As shown, although a good magnetic force can be obtained throughout the permanent magnet 23, the magnetic force in the central portion 23x in the vertical direction is slightly weaker than that in other parts. That is, since the magnetic force at the axial central position of the magnetizing device 30 is slightly weaker, by deliberately arranging the spacer 51 at this position, it is possible to efficiently magnetize the multiple rotors 20 with small differences between them.

[0081] Furthermore, the location of the spacer 51 is not limited to the above and can be appropriately changed. For example, if it is positioned at the bottom of the rotor 20, then only the rotor 20 to be magnetized needs to be removed from the magnetizing device 30 each time the rotor 20 is magnetized. Therefore, the spacer 51 can always be positioned in the magnetizing device 30. Additionally, while the spacer 51 is used to fill the axial gap in the rotor mounting space 30x, a magnetic metal spacer (not shown) that fills the radial gap according to the outer diameter of the rotor 20 or the inner diameter of the shaft insertion hole 22b can also be used. That is, for the rotor mounting space 30x, a magnetic metal spacer that fills the axial or radial gap according to the size or number of the rotors 20 to be magnetized can also be used. Alternatively, the rotor 20 can be magnetized without using such a spacer, even with a gap in the rotor mounting space 30x.

[0082] • The magnetizing device 30 is configured such that an upper part 41 is disposed above the main body 31, but the configuration of the magnetizing device 30 is not limited to this. For example, the main body 31 and the upper part 41 may be arranged in an inclined direction or a horizontal direction other than the vertical direction.

[0083] · Figure 2 and Figure 9 The shape of the permanent magnet 23 shown is one example, and it can be changed appropriately.

[0084] · Figure 1 The structure of the rotary motor M shown is an example, and it can be modified appropriately.

[0085] The technical ideas that can be grasped from the above-described implementation methods and variations are recorded.

[0086] (A) A method for manufacturing a rotor in which the shaft insertion hole of the rotor into which an insertion protrusion serving as an insertion portion of a second yoke is inserted when the permanent magnet is magnetized is configured to include a tapered portion (22x) with an opening set in an expanding shape.

[0087] While this disclosure has been described based on embodiments, it should be understood that this disclosure is not limited to the above embodiments and structures. This disclosure also includes various modifications and equivalent variations. Furthermore, various combinations and arrangements, including combinations and arrangements with only one element, or more than one or fewer elements, also fall within the scope and spirit of this disclosure.

Claims

1. A manufacturing apparatus of a rotor, the manufacturing apparatus of the rotor includes a magnetizing device configured to magnetize a permanent magnet of the rotor from an outside of the rotor, the rotor includes a rotor core having a magnet housing hole, the permanent magnet is disposed in a state of being embedded in the magnet housing hole, and has a convex fold shape that protrudes toward a radially inner side, the magnetizing device includes: a first yoke portion having an opposite portion opposite to an outer peripheral surface of the rotor; a second yoke portion that forms a magnetic circuit with the first yoke portion and has an insertion portion inserted into an axial insertion hole of the rotor before a rotating shaft is inserted, or a connection portion magnetically connected to the rotating shaft inserted into the axial insertion hole of the rotor; and a magnetizing coil provided on the magnetic circuit of the first yoke portion and the second yoke portion, the magnetizing device is configured to cause a magnetizing magnetic flux to flow at least inside the rotor between the opposite portion of the first yoke portion and the insertion portion of the second yoke portion or the rotating shaft in a diametrically opposite relationship with respect to the rotor, based on energization to the magnetizing coil, thereby magnetizing the permanent magnet in the embedded state.

2. The manufacturing apparatus of the rotor according to claim 1, wherein the magnetizing coil includes a first magnetizing coil wound around the opposite portion of the first yoke portion, and a second magnetizing coil wound around a vicinity of the insertion portion of the second yoke portion or the connection portion, the magnetizing coil is configured to generate a magnetizing magnetic flux by cooperative action of the first magnetizing coil and the second magnetizing coil.

3. The manufacturing apparatus of the rotor according to claim 2, wherein the first magnetizing coil is provided in a plurality in a circumferential direction of the rotor, and is provided corresponding to a rotor pole portion including the permanent magnet, and in contrast to this, the second magnetizing coil is provided commonly for different poles of the rotor pole portion, the second magnetizing coil is configured to switch a direction of the magnetizing magnetic flux in a pole switching energization mode for each magnetization of the permanent magnet.

4. The manufacturing apparatus of the rotor according to claim 2, wherein the second yoke portion and the second magnetizing coil are provided in a pair symmetrically at one side and the other side in an axial direction of the rotor that is a magnetization target.

5. The manufacturing apparatus of the rotor according to claim 3, wherein the second yoke portion and the second magnetizing coil are provided in a pair symmetrically at one side and the other side in an axial direction of the rotor that is a magnetization target.

6. The manufacturing apparatus of the rotor according to any one of claims 1 to 5, wherein a tip portion of an insertion protrusion portion that is the insertion portion of the second yoke portion includes a tapered portion in a tapered shape.

7. The manufacturing apparatus of the rotor according to any one of claims 1 to 5, wherein insertion protrusion portions that are the insertion portion of the second yoke portion are provided in a movable portion and a stationary portion of the magnetizing device, respectively, a protruding length of the insertion protrusion portion provided in the movable portion is shorter than a protruding length of the insertion protrusion portion provided in the stationary portion.

8. The manufacturing apparatus for a rotor according to any one of claims 1 to 5, characterized in that the magnetizing device includes a spacer made of a magnetic material disposed in a manner to fill a gap generated in the rotor, in a rotor setting space for setting the rotor as the magnetizing object.

9. The manufacturing apparatus for a rotor according to any one of claims 1 to 5, characterized in that the magnetizing device includes a restriction member that restricts deformation and movement of the magnetizing coil.

10. A manufacturing method for a rotor, the manufacturing method for a rotor using a magnetizing device, the magnetizing device configured to magnetize a permanent magnet of a rotor from outside the rotor, the rotor including a rotor core having a magnet housing hole, the permanent magnet being disposed in a state of being buried in the magnet housing hole and assuming a convexly folded-back shape that protrudes toward a radially inner side, the magnetizing device including: a first yoke portion having an opposing portion opposite to an outer peripheral surface of the rotor; a second yoke portion that forms a magnetic circuit with the first yoke portion and has an insertion portion inserted into an axle insertion hole of the rotor before the axle is inserted or a linking portion magnetically linked with the axle inserted into the axle insertion hole of the rotor; and a magnetizing coil disposed on the magnetic circuit of the first and second yoke portions, the manufacturing method including: causing magnetizing magnetic flux to flow at least inside the rotor between the opposing portion of the first yoke portion and the insertion portion of the second yoke portion or the axle in an opposite relationship in a radial direction of the rotor, based on energization of the magnetizing coil, thereby magnetizing the permanent magnet in the buried state.

11. A rotor manufactured by the manufacturing method for a rotor according to claim 10, the rotor configured to have a permanent magnet disposed in a state of being buried in a magnet housing hole and assuming a convexly folded-back shape that protrudes toward a radially inner side, and configured to magnetize the permanent magnet in the buried state from outside using a magnetizing device, the permanent magnet assuming a deep folded-back shape in which a buried depth is greater than a pole pitch when a line extending from an inner side surface of the permanent magnet of the folded-back shape to an outer peripheral surface of the rotor core on a circumferential center line of the permanent magnet is set as the pole pitch and a distance from the outer peripheral surface of the rotor core to the inner side surface of the curved portion of the permanent magnet on the circumferential center line of the permanent magnet is set as the buried depth, the permanent magnet being magnetized in a manner in which a volume ratio of a portion of the permanent magnet in which magnetization is performed using a magnetic field intensity exceeding a desired lower limit value exceeds 90% in a case where an inflection point at which a change in the magnetic field intensity generated by the magnetization of the permanent magnet becomes gentle is set as the desired lower limit value. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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