Rotor manufacturing method and rotor manufacturing device

Abstract

To provide a manufacturing method and a manufacturing device of a rotor, which enable assembly of a magnet and full magnetization with a simple method in a spork-type IPM motor.SOLUTION: When a rotor 1 of a spork-type IPM motor is manufactured, a magnetizer 11 in which a magnet receiving hole 16 of a magnetizing part 15 which magnetizes a magnet 6 is provided in a position corresponding to a magnet mounting hole 5 of a rotor core 3 is used. In the magnetizer 11, the rotor core 3 is arranged so that the magnet mounting hole 5 of the rotor core 3 and the magnet receiving hole 16 of the magnetizer 11 face each other and communicate each other. The magnet 6 after magnetization processing by the magnetizer 11 is inserted and installed into the magnet mounting hole 5 of the rotor core 3 from the magnet receiving hole 16, and the magnet 6 magnetized in the magnetizer 11 is directly inserted into the magnet mounting hole 5 in the same position as it is from the magnet receiving hole 16 to be installed.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a manufacturing technique for a rotor for an electric motor, and more particularly to a magnetizing technique for an interior permanent magnet (IPM) motor. [Background technology]

[0002] In recent years, the use of brushless motors with an IPM structure (hereafter referred to as IPM motors), which have magnets embedded in the rotor, has been increasing as drive sources for electric vehicles, hybrid vehicles, etc. IPM motors can utilize both the torque from the magnet and the reluctance torque that accompanies the magnetization of the rotor, and the magnet will not come off the rotor while the motor is rotating, so they are widely used in fields that require high performance and mechanical reliability.

[0003] Unlike SPM (Surface Permanent Magnet) motors, which have magnets arranged on the outer periphery of the rotor, such IPM motors have magnets embedded inside the rotor core. Therefore, in order to arrange magnets inside the rotor in IPM motors, the conventional method is to insert an unmagnetized magnet (material) into the rotor in advance, and then mount the rotor in that state on a magnetizer to magnetize the magnet.

[0004] However, in IPM motors with spoke-type magnets arranged radially, the magnets are arranged along the radial direction, making it difficult for the magnetic field of the magnetizer to reach the radially inner part of the magnet (towards the center of the rotor). This means that the magnet cannot be fully magnetized all the way to the inside, and the magnetic flux of the magnet decreases as it approaches the inside of the rotor, resulting in a problem of reduced motor output due to uneven magnetic flux. Therefore, in spoke-type IPM motors, the magnets are magnetized before mounting the rotor, and then the fully magnetized magnets are incorporated into the rotor, ensuring that the performance of the magnets is fully utilized. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2006-304556 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the case of the method of magnetizing first, when the magnet is assembled into the rotor, the magnet is already magnetized, so the magnet is attracted to the metallic rotor core by its magnetic attraction, making it difficult to insert and assemble the magnet into the rotor. Also, if the magnet sticks to the rotor core when attaching it to the rotor, there is a risk that the magnet will crack or chip during assembly. Furthermore, there is also the problem that each magnetized magnet needs to be inserted in the correct direction to fit the insertion hole in the rotor, making the work even more complicated.

[0007] An object of the present invention is to provide a rotor manufacturing method and manufacturing apparatus that allows magnets to be assembled and fully magnetized in a spoke-type IPM motor using a simple method. [Means for solving the problem]

[0008] The rotor manufacturing method of the present invention is a method for manufacturing a rotor for an electric motor, the rotor core having a rotor core with a plurality of magnet mounting holes formed along the circumferential direction, and magnets arranged in the magnet mounting holes, the magnet mounting holes being arranged radially inside the rotor core, and is characterized in that a magnetizer is used as a magnetizer for magnetizing the magnet, the magnetizer having a magnet accommodating hole of a magnetizing part that magnetizes the magnet at a position corresponding to the magnet mounting hole, the unmagnetized magnet is attached to the magnet accommodating hole of the magnetizer, the rotor core is positioned on the magnetizer so that the magnet mounting hole of the rotor core and the magnet accommodating hole of the magnetizer face each other and communicate with each other, the unmagnetized magnet is magnetized using the magnetizer, and the magnet after magnetization is inserted and attached through the magnet accommodating hole into the magnet mounting hole of the rotor core.

[0009] In the present invention, a magnetizer is used that has a magnet accommodating hole in a magnetizing section that magnetizes the magnet at a position corresponding to the magnet mounting hole, and the rotor core is arranged so that the magnet mounting hole of the rotor core faces and communicates with the magnet accommodating hole of the magnetizer. The magnetized magnet is then inserted and attached from the magnet accommodating hole into the magnet mounting hole of the rotor core, so that the magnet magnetized by the magnetizer is inserted and attached into the magnet mounting hole in the same position as the magnet accommodating hole. As a result, a magnet that has been magnetized evenly as a whole by the magnetizer is assembled into the rotor core, and the magnetic flux of the magnet does not decrease radially inward, and a motor using this rotor is prevented from experiencing a decrease in output due to uneven magnetic flux.

[0010] In the rotor manufacturing method, the unmagnetized magnet installed in the magnet accommodating hole may be accommodated and held in the magnet accommodating hole in a state where it is clamped from above and below by pressing members respectively arranged above and below the magnet accommodating hole, and after the magnetization process, the magnet in the magnet accommodating hole may be inserted into the magnet accommodating hole by the pressing members.

[0011] Furthermore, in the rotor manufacturing method, half of the magnets may be magnetized to a first polarity and inserted and attached into the magnet mounting holes of the rotor core, and then the remaining half of the magnets may be magnetized to a second polarity opposite to the first polarity and inserted and attached into the magnet mounting holes.

[0012] In this case, the rotor core may be attached to the magnetizer, half of the magnets may be magnetized to the first polarity, the magnetized magnets may be inserted and attached into the designated magnet mounting holes, the rotor core may be temporarily removed from the magnetizer, the remaining half of the unmagnetized magnets may be attached to the magnetizer, the rotor core may be rotated from the position where the first polarity magnetization process was performed, and the rotor core may be positioned so that the empty magnet mounting holes of the rotor core face and communicate with the magnet accommodating holes of the magnetizer, and in this state the unmagnetized magnets may be magnetized to the second polarity, and the magnetized magnets may be inserted and attached into the empty magnet mounting holes.

[0013] Alternatively, a first magnetizer that performs magnetization processing of the first polarity and a second magnetizer that performs magnetization processing of the second polarity may be used as the magnetizer, the rotor core may be attached to the first magnetizer, half of the magnets may be magnetized with the first polarity using the first magnetizer, the magnetized magnets may be inserted and attached into the predetermined magnet mounting holes, the rotor core may be removed from the first magnetizer, the remaining half of the unmagnetized magnets may be attached to the second magnetizer, the rotor core may be positioned so that the empty magnet mounting holes of the rotor core face and communicate with the magnet accommodating holes of the second magnetizer, the unmagnetized magnets may be magnetized with the second magnetizer, and the magnetized magnets may be inserted and attached into the empty magnet mounting holes.

[0014] On the other hand, the rotor manufacturing apparatus of the present invention is a manufacturing apparatus for a rotor for an electric motor, which has a rotor core having a plurality of magnet mounting holes formed along the circumferential direction, and magnets arranged in the magnet mounting holes, the magnet mounting holes being arranged radially inside the rotor core, and a magnet accommodating hole of a magnetizing section which magnetizes the magnet is provided at a position corresponding to the magnet mounting hole, and is equipped with a magnetizer capable of positioning the rotor core so that the magnet mounting hole of the rotor core faces and communicates with the magnet accommodating hole, and the magnetizer performs a magnetizing process on the unmagnetized magnet installed in the magnet accommodating hole, and the magnet after magnetization is inserted and installed into the magnet mounting hole of the rotor core through the magnet accommodating hole.

[0015] In the present invention, the magnetizer is provided with a magnet accommodating hole of a magnetizing section that magnetizes the magnet at a position corresponding to the magnet mounting hole, and the rotor core can be arranged so that the magnet mounting hole of the rotor core and the magnet accommodating hole of the magnetizer face each other and communicate with each other, and the magnet after magnetization is inserted and attached from the magnet accommodating hole into the magnet mounting hole of the rotor core, so that the magnet magnetized by the magnetizer is inserted and attached from the magnet accommodating hole into the magnet mounting hole of the rotor core at the same position. Therefore, the magnet that has been magnetized evenly as a whole by the magnetizer is assembled into the rotor core, and the magnetic flux of the magnet does not decrease radially inward, and in a motor using this rotor, output reduction due to magnetic flux unevenness is suppressed.

[0016] In the rotor manufacturing apparatus, there may further be provided a clamping member arranged above and below the magnet accommodating hole, which clamps the magnet mounted in the magnet accommodating hole from above and below and holds the magnet in the magnet accommodating hole, and the magnet in the magnet accommodating hole is fed from the magnet accommodating hole into the magnet mounting hole of the rotor core by the clamping member.

[0017] The magnetizer may be capable of magnetizing the magnet to a first polarity and a second polarity opposite to the first polarity.

[0018] Furthermore, the magnetizers may include a first magnetizer that performs a magnetization process of a first polarity and a second magnetizer that performs a magnetization process of a second polarity opposite to the first polarity, and the first magnetizer may perform the magnetization process of the first polarity on half of the magnets, and the second magnetizer may perform the magnetization process of the second polarity on the remaining half of the magnets that are not magnetized. Effect of the Invention

[0019] According to the rotor manufacturing method of the present invention, when manufacturing a rotor for an electric motor having a rotor core with a plurality of magnet mounting holes formed along the circumferential direction and magnets arranged in the magnet mounting holes, the magnet mounting holes being arranged radially inside the rotor core, a magnetizer having magnet accommodating holes in a magnetizing portion for magnetizing the magnets at positions corresponding to the magnet mounting holes is used, and the rotor core is arranged so that the magnet mounting holes of the rotor core and the magnet accommodating holes of the magnetizer face each other and communicate with each other. Then, the magnets after magnetization are inserted and mounted from the magnet accommodating holes into the magnet mounting holes of the rotor core, so that the magnets magnetized by the magnetizer can be inserted and mounted in the magnet mounting holes at the same position from the magnet accommodating holes. Therefore, the magnets magnetized evenly as a whole by the magnetizer can be assembled into the rotor core, and the magnetic flux of the magnets does not decrease toward the radial inside, making it possible to suppress a decrease in motor output caused by magnetic flux unevenness.

[0020] According to the rotor manufacturing apparatus of the present invention, in an apparatus for manufacturing a rotor for an electric motor, the rotor core has a plurality of magnet mounting holes formed along the circumferential direction, and magnets arranged in the magnet mounting holes, the magnet mounting holes being arranged radially inside the rotor core, the magnet accommodating holes of a magnetizing part for magnetizing the magnets are provided at positions corresponding to the magnet mounting holes, the magnetizer is provided for arranging the rotor core so that the magnet mounting holes of the rotor core and the magnet accommodating holes of the magnetizer face each other and communicate with each other, and the magnets after magnetization are inserted and attached from the magnet accommodating holes into the magnet mounting holes of the rotor core, so that the magnets magnetized by the magnetizer can be inserted and attached from the magnet accommodating holes into the magnet mounting holes of the rotor core as they are, and therefore the magnets magnetized by the magnetizer can be assembled into the rotor core from the magnet accommodating holes, and the magnets magnetized by the magnetizer can be assembled into the magnet mounting holes in the same position as they are from the magnet accommodating holes. Therefore, the magnets magnetized evenly as a whole by the magnetizer can be assembled into the rotor core, and the magnetic flux of the magnets does not decrease radially inward, making it possible to suppress a decrease in motor output caused by magnetic flux unevenness. [Brief description of the drawings]

[0021] [Figure 1] 1 is an explanatory diagram showing a configuration of a rotor to which a rotor manufacturing method according to an embodiment of the present invention is applied; [Diagram 2] 1 is an explanatory diagram showing a configuration of a rotor manufacturing apparatus to which a rotor manufacturing method according to an embodiment of the present invention is applied; [Diagram 3] FIG. 2 is an explanatory diagram showing the configuration of a magnetizing yoke. [Figure 4] FIG. 2 is an explanatory diagram showing a configuration in the vicinity of a magnetizer. [Diagram 5] 3 is an explanatory diagram showing a rotor manufacturing process using the rotor manufacturing apparatus of FIG. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Fig. 1 is an explanatory diagram showing the configuration of a rotor 1 to which a rotor manufacturing method according to one embodiment of the present invention is applied, and Fig. 2 is an explanatory diagram showing the configuration of a rotor manufacturing apparatus 10 to which the rotor manufacturing method is applied. The rotor 1 is used in an inner rotor type IPM motor, and as shown in Fig. 1, is configured by press-fitting and fixing a cylindrical rotor core 3 onto the outer periphery of a rotor shaft 2. The rotor core 3 is made of a magnetic material and is configured by laminating a plurality of substantially circular thin core plates (steel sheet material).

[0023] An axial hole 4 is provided in the center of the rotor core 3. The rotor shaft 2 is press-fitted and fixed in the axial hole 4. A plurality of magnet mounting holes 5 are formed around the axial hole 4 along the circumferential direction. The magnet mounting holes 5 are provided radially, extending in the radial direction, giving the rotor 1 a so-called spoke-type configuration. Magnets (permanent magnets) 6 are inserted and housed in the magnet mounting holes 5.

[0024] In the rotor core 3 of this embodiment, ten magnet mounting holes 5 are provided at equal intervals along the circumferential direction, and ten magnets 6 are embedded in the rotor core 3. The magnets 6 are arranged so that adjacent magnets in the circumferential direction have opposite polarity. In other words, there are five magnets 6 of the same polarity, and magnets of different polarity are arranged alternately in the circumferential direction. A groove 7 extending in the circumferential direction is formed on the inner peripheral side of the magnet mounting holes 5. Magnet holders 8 made of synthetic resin, which also serve to position the magnets 6 in the radial direction, are attached to both axial ends of the rotor core 3.

[0025] For such a rotor 1, in the rotor manufacturing method according to the present invention, a magnetizer 11 having a plurality of magnetized parts arranged radially is used to magnetize the magnet 6. As shown in FIG. 2, the magnetizer 11 is arranged in the center of the rotor manufacturing apparatus 10, and the magnet 6 is magnetized and attached with the rotor 1 arranged on the upper surface of the magnetizer 11. The magnetizer 11 is installed on a magnetizer base 12 arranged in the center of the rotor manufacturing apparatus 10. A cylindrical case 13 is placed on the magnetizer base 12, and a magnetizing yoke 14 formed into a substantially pentagonal prism shape as a whole is housed inside the case 13. FIG. 3 is an explanatory diagram showing the configuration of the magnetizing yoke 14, and the magnetizing yoke 14 is provided with five magnetized parts 15 in the same positional relationship as the magnet mounting holes 5 of the rotor core 3.

[0026] The magnetized portion 15 is provided with a magnet accommodating hole 16 in which the magnet 6 is accommodated. The magnet accommodating hole 16 is arranged at a position corresponding to the magnet mounting hole 5 of the rotor core 3. The magnetized portion 15 is further provided with a magnetizing coil 17 adjacent to the magnet accommodating hole 16. The space between the magnetized portions 15 forms an iron core yoke portion 18, and the magnetizing coil 17 is wound around the iron core yoke portion 18.

[0027] 4, a communication hole 13b is formed in a case top surface 13a of the magnetizer 11 in correspondence with the magnet accommodating hole 16. A shaft insertion hole 13c, through which the rotor shaft 2 of the rotor 1 is inserted, is also formed in the case top surface 13a. When the rotor 1 is attached to the case top surface 13a of the magnetizer 11 while inserting the rotor shaft 2 into the shaft insertion hole 13c, the magnet mounting hole 5 of the rotor core 3 and the magnet accommodating hole 16 of the magnetizer 11 face each other via the communication hole 13b and communicate with each other.

[0028] Two rotor positioning protrusions 19a, 19b are further provided on the case top surface 13a of the magnetizer 11. The rotor positioning protrusions 19a, 19b fit into two adjacent grooves 7 on the inner periphery of the magnet mounting hole 5 of the rotor core 3 to prevent the rotor core 3 arranged on the magnetizer 11 from rotating in the circumferential direction and to position the rotor core 3 in the circumferential direction so that the magnet mounting hole 5 and the magnet accommodating hole 16 communicate with each other.

[0029] The rotor manufacturing apparatus 10 is configured such that the magnetizer 11 is disposed in the center, with a rotor support section 21 and an upper magnet holding mechanism 22 disposed above the magnetizer 11, and a lower magnet holding mechanism 23 disposed below the magnetizer 11. The rotor support section 21 is a portion of the rotor manufacturing apparatus 10 that supports and fixes the rotor 1 from above, and has a rotor support rod 24 that supports the upper end of the rotor shaft 2. The lower end of the rotor support rod 24 is provided with a fitting holding section 25 in which a recess 25a that fits with the upper end of the rotor shaft 2 is formed.

[0030] Furthermore, the rotor support part 21 is equipped with a toggle clamp 26 for moving the rotor support rod 24 up and down and fixing the rotor 1 on the case upper surface 13a of the magnetizer 11. The toggle clamp 26 is installed on a top plate 27 on the upper end side of the rotor manufacturing apparatus 10. The top plate 27 is fixedly supported on a bottom plate 29 by four supports 28.

[0031] In the rotor manufacturing apparatus 10, the rotor 1 with only the upper magnet holder 8 attached is placed on the magnetizer 11. Next, the lever 26a of the toggle clamp 26 is slightly operated to move the rotor support rod 24 downward, and the upper end of the rotor shaft 2 is fitted into the recess 25a of the fitting and holding portion 25 to temporarily hold the rotor 1. After that, the sleeve 30 is attached to the rotor shaft 2 from the side. The sleeve 30 has a substantially U-shaped cross section, and is inserted and attached to the rotor shaft 2 from the opening. Then, the lever 26a of the toggle clamp 26 is further operated to move the rotor support rod 24 downward, and the sleeve 30 is sandwiched between the upper surface of the magnet holder 8 and the lower surface of the fitting and holding portion 25. As a result, the magnet holder 8 is pressed by the sleeve 30, and the rotor 1 is fixed and supported on the magnetizer 11 via the magnet holder 8.

[0032] The magnet upper holding mechanism 22 presses and holds the magnet 6 housed in the magnetizer 11 from above, and has magnet upper pressing pins 31 (pressing members, hereinafter abbreviated as upper pressing pins 31) that come into contact with the upper ends of the magnets 6 inside the magnetizer 11. The upper pressing pins 31 are attached to the lower surface side of an upper movable plate 32 provided above the magnetizer 11. Five upper pressing pins 31 are provided above each magnet accommodating hole 16 in correspondence with the magnet accommodating holes 16 of the magnetizer 11.

[0033] The upper movable plate 32 is provided so as to be movable vertically along a plate guide 33 attached to the underside of the top plate 27. The plate guide 33 is connected to an air cylinder 34 attached to the top plate 27, and is moved vertically by the air cylinder 34. When the upper movable plate 32 is moved downward, the upper pressing pin 31 also moves downward and is inserted into the rotor 1 arranged on the magnetizer 11. The magnet holder 8 on the rotor core 3 is provided with a pin insertion hole 8a corresponding to the magnet accommodating hole 16, and the upper pressing pin 31 passes through the pin insertion hole 8a and the magnet mounting hole 5 of the rotor core 3 and abuts against the upper end of the magnet 6 accommodated in the magnet accommodating hole 16 of the magnetizer 11. As a result, the magnet 6 in the magnetizer 11 is pressed and held from above.

[0034] The magnet lower holding mechanism 23 supports the magnet 6 housed in the magnetizer 11 from below, and further pushes it upward to insert it from inside the magnetizer 11 into the magnet mounting hole 5 of the rotor core 3. The magnet lower holding mechanism 23 has a magnet lower pressing pin 41 (pressing member, hereinafter abbreviated as lower pressing pin 41) that abuts against the lower end of the magnet 6 inside the magnetizer 11, and a lower movable plate 42 for actuating the lower pressing pin 41 in the vertical direction.

[0035] The lower movable plate 42 is disposed below the magnetizer 11 and is provided so as to be movable in the vertical direction, and the lower pressing pin 41 is attached to the upper surface side of the lower movable plate 42. Five lower pressing pins 41 are also provided corresponding to the magnet accommodation holes 16 of the magnetizer 11. The upper pressing pin 31 and the lower pressing pin 41 are arranged in a vertical line. The lower movable plate 42 is provided so as to be movable in the vertical direction along a plate guide 43 attached to the lower surface side of the magnetizer base 12. The plate guide 43 is connected to an air cylinder 44 attached on the bottom plate 29 and is operated in the vertical direction by the air cylinder 44. A pin guide 45 into which the lower pressing pin 41 is inserted and supported is attached to the center of the magnetizer base 12. The pin guide 45 is provided with five guide holes 46 into which the lower pressing pins 41 can be inserted.

[0036] When the lower movable plate 42 is moved upward, the lower pressing pin 41 also moves upward and is inserted into the magnet accommodating hole 16 of the magnetizer 11. The lower pressing pin 41 is set in its initial position at a position where its upper end abuts against the lower end of the magnet 6 in the magnet accommodating hole 16. As a result, the magnet 6 in the magnetizer 11 is supported from below by the upper end surface of the lower pressing pin 41. After the magnetization process of the magnet 6 is completed, when the lower pressing pin 41 is moved further upward, the magnet 6 in the magnetizer 11 is pushed upward by the upper end surface of the lower pressing pin 41 and fed into the magnet mounting hole 5 of the rotor core 3.

[0037] Next, a method of magnetizing the magnets 6 using rotor manufacturing apparatus 10 and assembling them into rotor core 3 to manufacture the rotor 1 will be described. Figure 5 is an explanatory diagram showing the rotor manufacturing process using rotor manufacturing apparatus 10. In rotor manufacturing apparatus 10, half of the total ten magnets 6 (five magnets with the same polarity) are magnetized and assembled into rotor core 3 in one process of Figures 5(a) to (e).

[0038] In the rotor manufacturing apparatus 10, the lower pressing pin 41 is set in advance at a magnet supporting position where its upper end abuts against the lower end of the magnet 6, and in this state, an unmagnetized magnet 6 is supplied to the magnetizer 11. That is, the magnet 6 is inserted and accommodated in the magnet accommodating hole 16 of the magnetizer 11 through the communication hole 13b in the case top surface 13a (FIG. 5(a): magnet supplying step). At this time, the magnet 6 in the magnet accommodating hole 16 is supported from below by the lower pressing pin 41.

[0039] Next, the rotor shaft 2 is inserted into the shaft insertion hole 13c in the case top surface 13a, and the rotor 1 is placed on the magnetizer 11 (FIG. 5(b)). The rotor 1 is set in a predetermined rotational position by fitting the rotor positioning protrusions 19a, 19b on the top surface of the magnetizer 11 into the groove portion 7 of the rotor core 3. Here, the supply of the magnet 6 and the attachment and detachment of the rotor 1 are performed manually, but these can also be automated, and such a method is preferable for mass production. After the rotor 1 is placed on the top surface of the magnetizer 11, the sleeve 30 is attached while operating the toggle clamp 26, and the rotor support rod 24 is lowered. As a result, the fitting and holding portion 25 of the rotor support rod 24 fits into the upper end of the rotor shaft 2 of the rotor 1, and the rotor 1 is pushed from above by the sleeve 30, and the rotor 1 is fixed and supported on the magnetizer 11 (FIG. 5(b): rotor supply and fixation process).

[0040] After the rotor 1 is fixed and supported on the magnetizer 11, the air cylinder 34 is operated to move the upper movable plate 32 downward. This causes the upper pressing pin 31 to move downward, pass through the pin insertion hole 8a of the magnet holder 8, and enter the magnet mounting hole 5 of the rotor core 3 arranged on the magnetizer 11. When the upper pressing pin 31 is further lowered, the lower end of the upper pressing pin 31 enters the magnet accommodating hole 16 of the magnetizer 11 through the communication hole 13b and abuts against the upper end of the magnet 6 accommodated therein. As a result, the magnet 6 is pressed from above, and is sandwiched and held from above and below by both pins 31 and 41, and is accommodated and held in the magnet mounting hole 5 (FIG. 5(c)).

[0041] After the magnets 6 are accommodated and held in the magnet mounting holes 5, the magnetizer 11 performs a magnetization process for the magnets 6 (FIG. 5(c): magnet accommodation, holding, and magnetization process). That is, a current is supplied to the magnetizing coil 17 in a predetermined direction to magnetize the five magnets 6 to the same polarity (first polarity, for example, N→S clockwise). At this time, in the rotor manufacturing method and apparatus according to the present invention, the magnetizer 11 can magnetize the entire magnets 6 evenly without causing differences in magnetic flux depending on the location. Therefore, when the magnetized magnets 6 are assembled into the rotor core 3, the magnetic flux of the magnets 6 does not decrease radially inward, and a motor using the rotor 1 can stably obtain the desired output without incurring a decrease in output due to magnetic flux unevenness.

[0042] After magnetizing the magnet 6, the air cylinder 44 is operated to move the lower movable plate 42 upward to move the lower pressing pin 41 upward. At this time, the pressing force of the upper pressing pin 31 is set to be weaker than the upward pressing force of the lower pressing pin 41, and the lower pressing pin 41 moves upward against the pressing force of the upper pressing pin 31. As a result, the magnet 6 in the magnetizer 11 is pushed upward by the lower pressing pin 41 while being held upside down, and is directly inserted into the magnet mounting hole 5 of the rotor core 3 (FIG. 5(d): magnetized magnet insertion process). At this time, the upper end of the magnet 6 is held down by the magnet holder 8. That is, the pin insertion hole 8a of the magnet holder 8 is smaller than the cross section of the magnet 6, although the upper pressing pin 31 can pass through it, and the magnet 6 pushed up comes into contact with the lower surface of the magnet holder 8 and stops.

[0043] After the lower pressing pin 41 is moved upward and the magnetized magnet 6 is inserted into the rotor core 3, the air cylinder 34 is operated to move the upper movable plate 32 upward. The upper movable plate 32 is moved to just below the top plate 27, and the upper pressing pin 31 is withdrawn to above the rotor 1. Then, the air cylinder 44 is lowered to remove the lower pressing pin 41. Then, the toggle clamp 26 is operated to raise the rotor support rod 24, the sleeve 30 is removed from the rotor shaft 2, and the rotor support rod 24 is detached from the rotor shaft 2. This frees the rotor 1 on the magnetizer 11, making it possible to remove it from the apparatus (FIG. 5(e): rotor removal process).

[0044] In this way, five magnets 6 are magnetized and accommodated in the rotor core 3, and then the remaining five magnets 6 are magnetized. That is, as shown in FIG. 5(e), the rotor 1 in a free state after the first half of the process is removed from the magnetizer 11, and the process from FIG. 5(a) is carried out again as the second half of the process. In this case, after the magnet 6 is set again in the process of FIG. 5(a), in the process of FIG. 5(b), the rotor 1 is shifted in the circumferential direction by one magnet mounting hole 5 from the rotation position in the first half of the process, and the rotor positioning protrusions 19a, 19b are fitted into the groove 7 at that position and set in the magnetizer 11. That is, the rotor 1 is set so that the magnet mounting hole 5 into which the magnet 6 is not inserted faces and communicates with the magnet accommodation hole 16 of the magnetizer 11.

[0045] Then, in the process of FIG. 5(c), a current is supplied to the magnetizing coil 17 of the magnetizer 11 in the opposite direction to that in the first half of the process, and the five magnets 6 are magnetized with the opposite polarity to the previous one (second polarity, counterclockwise from N to S in the previous example). Then, the magnets 6 magnetized with this opposite polarity are inserted into the magnet mounting holes 5 that were left empty in the first half of the process (FIG. 5(d)). As a result, the magnets 6 are housed and arranged in the rotor core 3 such that adjacent magnets 6 in the circumferential direction have opposite polarities to each other. The rotor 1 with the ten magnets 6 magnetized and embedded in this way is removed from the device (FIG. 5(e)), and the magnet holder 8 is attached, etc., to complete the rotor 1.

[0046] As described above, in the rotor manufacturing method and apparatus according to the present invention, a magnetizer 11 is used in which magnet accommodating holes 16 of a magnetizing section 15 are provided at positions corresponding to magnet mounting holes 5 of rotor core 3. Furthermore, rotor 1 is set in magnetizer 11 with magnet mounting holes 5 and magnet accommodating holes 16 facing each other and communicating with each other. Magnet 6 magnetized by magnetizing section 15 is inserted and attached to magnet mounting hole 5 in the same position from magnet accommodating hole 16. These steps are performed within the apparatus by using two pressing pins 31, 41 that are movable in the vertical direction and that clamp magnet 6 from above and below within magnet mounting hole 5.

[0047] As a result, the magnet 6, which has been magnetized evenly throughout by the magnetizer 11, is assembled into the rotor core 3, and the magnetic flux of the magnet 6 does not decrease radially inward. Therefore, in a motor using a rotor 1 manufactured by the rotor manufacturing method and apparatus of the present invention, it is possible to stably obtain the desired output without incurring a decrease in output due to uneven magnetic flux. In addition, the magnetization and mounting of the magnet 6 can be performed in one go by the rotor manufacturing apparatus 10, eliminating the need for difficult and complicated work as in the past, thereby reducing the number of manufacturing steps for the rotor, reducing defective products, and improving reliability.

[0048] The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the spirit and scope of the present invention. For example, in the above embodiment, ten magnets 6 are magnetized and attached using one rotor manufacturing apparatus 10 by changing the set position of the rotor 1 and the polarity of the magnetizing coil 17. However, during mass production, two rotor manufacturing apparatuses 10 with different rotor set positions and polarity of the magnetizing coils, or an apparatus equipped with two magnetizers 11, may be used. When two apparatuses are used, magnetizers 11 (first and second magnetizers) that magnetize a set of five magnets 6 with different polarities are provided in each rotor manufacturing apparatus 10, and after the magnetization and attachment process by one apparatus (corresponding to the first half of the embodiment), each process by the other apparatus (corresponding to the second half of the embodiment) is performed. In addition, in the case of an apparatus equipped with two magnetizers 11, two of each mechanism of the rotor manufacturing apparatus 10 are arranged in one apparatus.

[0049] In the embodiment, the rotor core and magnets are manually set in the device, but as described above, it is also possible to set them automatically during mass production, etc. In that case, in a process using one rotor manufacturing device 10, the rotor or magnetizer may be automatically rotated and set in the rotor supply and fixing process in the latter half of the process, so that the empty magnet mounting hole on the rotor side faces the magnet accommodating hole on the magnetizer side, and the next or subsequent process is carried out. Also, in a process using two rotor manufacturing devices 10, automating the setting of the rotor core and magnets can improve production efficiency during mass production, etc. [Industrial Applicability]

[0050] The present invention is applied to the rotor of an IPM motor used as the drive source of an electric oil pump, for example, but can also be applied to rotors of various IPM motors used in electric power steering devices, electric brake systems, hybrid cars, electric cars, etc. Furthermore, the rotor of the present invention can be applied not only to motors related to automobiles, but also to motors for other electric machines and devices such as home appliances and industrial machines. [Explanation of symbols]

[0051] 1 rotor 2 rotor shaft 3 Rotor core 4 Shaft hole 5 Magnet mounting hole 6. Magnets 7 Groove 8 Magnet holder 8a Pin insertion hole 10 Rotor manufacturing equipment 11 Magnetizer 12 Magnetizer base 13 cases 13a Case top 13b Communication hole 13c Shaft insertion hole 14 Magnetizing yoke 15 Magnetized part 16 Magnet storage hole 17 Magnetizing coil 18 Core yoke 19a, 19b Rotor positioning protrusions 21 Rotor support 22 Magnet upper holding mechanism 23 Magnet lower holding mechanism 24 Rotor support rod 25 Fitting retention part 26 Toggle Clamp 26a Lever 27 Top Plate 28 Posts 29 Bottom Plate 30 Sleeve 31 Magnet upper retaining pin (retaining member) 32 Upper movable plate 33 Plate Guide 34 Air Cylinder 41 Magnet lower retaining pin (retaining member) 42 Lower movable plate 43 Plate Guide 44 Air Cylinder 45 Pin Guide 46 Guide hole

Claims

1. A method for manufacturing a rotor for an electric motor, comprising: a rotor core having a plurality of magnet mounting holes formed along a circumferential direction; and magnets disposed in the magnet mounting holes, the magnet mounting holes being radially provided inside the rotor core, the method comprising: a magnetizer for magnetizing the magnet is provided with a magnet receiving hole of a magnetizing part for magnetizing the magnet at a position corresponding to the magnet mounting hole; The magnet that has not been magnetized is attached to the magnet receiving hole of the magnetizer, The rotor core is arranged on the magnetizer such that the magnet mounting hole of the rotor core faces and communicates with the magnet accommodating hole of the magnetizer; The magnetizer performs a magnetization process on the unmagnetized magnet, a magnet receiving hole for receiving the magnet from the magnet receiving hole, and a magnet mounting hole for mounting the magnet in the magnet receiving hole.

2. 2. The rotor manufacturing method according to claim 1, The unmagnetized magnet attached in the magnet accommodating hole is accommodated and held in the magnet accommodating hole in a state in which the magnet is sandwiched from above and below by pressing members respectively disposed above and below the magnet accommodating hole, The rotor manufacturing method is characterized in that the magnet is inserted into the magnet accommodating hole by the pressing member after magnetization processing.

3. 3. The rotor manufacturing method according to claim 1, further comprising the steps of: Half of the magnets are magnetized to a first polarity, and then inserted and attached into the magnet mounting holes of the rotor core. a rotor manufacturing method comprising the steps of: magnetizing the remaining half of said magnets with a second polarity opposite to the first polarity, and inserting and mounting said magnets in said magnet mounting holes.

4. 4. The rotor manufacturing method according to claim 3, Attaching the rotor core to the magnetizer, magnetizing half of the magnets with the first polarity, and inserting and mounting the magnetized magnets into predetermined magnet mounting holes; The rotor core is temporarily removed from the magnetizer, and the remaining half of the unmagnetized magnets are attached to the magnetizer. The rotor core is rotated from the position of the first polarity magnetization process, and the empty magnet mounting hole of the rotor core and the magnet accommodating hole of the magnetizer are disposed so as to face each other and communicate with each other; a magnetizing process for magnetizing the magnet with the second polarity while the magnet is still unmagnetized; and the magnetized magnet is inserted and attached into the empty magnet mounting hole.

5. 4. The rotor manufacturing method according to claim 3, As the magnetizer, a first magnetizer for performing a magnetization process of the first polarity and a second magnetizer for performing a magnetization process of the second polarity are used, Attaching the rotor core to the first magnetizer, magnetizing half of the magnets with the first polarity using the first magnetizer, and inserting and mounting the magnetized magnets into predetermined magnet mounting holes; removing the rotor core from the first magnetizer; The remaining half of the unmagnetized magnets are attached to the second magnetizer; The rotor core is arranged so that the empty magnet mounting hole of the rotor core faces and communicates with the magnet accommodating hole of the second magnetizer, a second magnetizer for magnetizing the unmagnetized magnet with the second polarity, and then inserting and mounting the magnet after magnetization into the empty magnet mounting hole.

6. An apparatus for manufacturing a rotor for an electric motor, the apparatus comprising: a rotor core having a plurality of magnet mounting holes formed along a circumferential direction; and magnets disposed in the magnet mounting holes, the magnet mounting holes being radially provided inside the rotor core; a magnetizer that can arrange the rotor core so that a magnet mounting hole of the rotor core faces the magnet mounting hole of the rotor core and the magnet accommodating hole of the magnetizing part that magnetizes the magnet is provided at a position corresponding to the magnet mounting hole, The magnetizer performs a magnetization process on the unmagnetized magnet installed in the magnet accommodating hole, and the magnet after magnetization is inserted from the magnet accommodating hole into the magnet mounting hole of the rotor core and installed in the rotor manufacturing apparatus.

7. 7. The rotor manufacturing apparatus according to claim 6, The rotor manufacturing apparatus further comprises: a pressing member disposed above and below the magnet accommodating hole, the pressing member sandwiching the magnet attached in the magnet accommodating hole from above and below and holding the magnet in the magnet accommodating hole, The rotor manufacturing apparatus is characterized in that the pressing member feeds the magnet in the magnet accommodating hole from the magnet accommodating hole into the magnet mounting hole of the rotor core.

8. 8. The rotor manufacturing apparatus according to claim 6, The rotor manufacturing apparatus is characterized in that the magnetizer is capable of magnetizing the magnet to a first polarity and a second polarity opposite to the first polarity.

9. 8. The rotor manufacturing apparatus according to claim 6, The magnetizer includes a first magnetizer that performs a magnetization process with a first polarity, and a second magnetizer that performs a magnetization process with a second polarity opposite to the first polarity, A rotor manufacturing apparatus characterized in that the first magnetizer performs magnetization processing of the first polarity on half of the magnets, and the second magnetizer performs magnetization processing of the second polarity on the remaining half of the magnets that are not magnetized.

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