JP2007043763A - Process for manufacturing rotor magnet, and motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process for manufacturing a rotor magnet in which a predetermined magnetized region can be formed suitably on the outer circumferential surface of a rotor magnet, and to provide a motor. <P>SOLUTION: Under a state where a premagnetized rotor magnet 22 is inserted into an insertion hole 130 formed in a magnetization yoke 11 in the axial direction, a magnetization coil provided on the magnetization yoke 11 is conducted thus magnetizing the outer circumferential surface of the rotor magnet 22. In this regard, a first magnetization coil 151 provided on the first magnetization yoke 111 and a second magnetization coil 152 provided on the second magnetization yoke 112 are employed as the magnetization coil. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a rotor magnet used in a stepping motor and the like, and a motor. More specifically, the present invention relates to a magnetizing technique for a rotor magnet.

  For example, as shown in FIG. 6A, the PM type stepping motor is configured such that the rotor magnet 22 is positioned inside the cylindrical stator 3. The stator 3 includes a first stator set 4 and a second stator set 5 that are arranged so as to overlap in the motor axial direction, and stator cores 41, 43, 51, 53 that constitute these stator sets 4, 5. Are provided with pole teeth facing the outer peripheral surface of the rotor magnet 22 (see, for example, Patent Document 1).

  Here, the stator cores 43 and 53 are often in direct contact with each other. In such a case, a large detent such that the magnetic flux from the rotor magnet 22 converges on the contact portion 30 and prevents the rotor magnet 22 from rotating. There is a problem that torque is generated. Such detent torque is not preferable because it causes vibration and noise. Therefore, when low vibration or low noise is required, as shown in FIG. 6B, the rotor magnet 22 having a so-called dumbbell structure in which the region facing the contact portion 30 of the stator cores 43 and 53 is recessed radially outward. (For example, refer to Patent Documents 1 and 2).

However, in order to manufacture the rotor magnet 22 having such a structure, the following method is a first conventional method: a method of separating two magnets,
Second conventional method: a method of molding a magnetic material into a dumbbell shape when injection molding,
Third conventional method: Since a method of cutting the inner peripheral surface of a straight cylindrical magnet is employed, there are various problems. For example, in the first conventional method, the processing cost and assembly cost of parts increase, and it is necessary to fix two magnets with an adhesive, so that the reliability is likely to decrease. Further, in the second conventional method, since it cannot be manufactured by normal compression molding, it must be manufactured by injection molding. For this reason, only materials that can be injection molded can be used, and such materials are expensive and have low magnetic performance. Further, the third conventional method has a problem that the cost is increased by the amount of additional processing required.

Therefore, as the rotor magnet 22, as shown in FIG. 6A, the outer diameter is constant in the axial direction, and the first magnetized region 221 and the second magnetized region 222 are provided on both sides in the axial direction. In addition, if a non-magnetized region 223 is used as the region facing the contact portion 30 of the stator cores 43 and 53, a stepping motor that suppresses generation of vibration and noise can be configured at low cost. As a method for manufacturing such a rotor magnet 22, as shown in FIG. 7, in the magnetizing yoke 11 used when magnetizing the rotor magnet 22, a portion of the magnet facing the central position in the axial direction of the rotor magnet 22 is not provided. A configuration in which a magnetic material 119 is inserted and a configuration in which an opening is provided in a portion facing the central position in the axial direction of the rotor magnet 22 have been proposed (see, for example, Patent Document 3).
JP 2003-60759 A JP 2005-57991 A JP-A-6-38493

  However, even when the configuration described in Patent Document 3 is adopted, as shown in FIGS. 8A, 8B, 8C, and 8D, the central position of the rotor magnet 22 in the axial direction is completely absent. The magnetized region 223 is not formed. 8 (a), (b), (c), and (d), the result of measuring the magnetic flux density of the outer peripheral surface of the rotor magnet 22 shown in FIG. 6 (a) was developed on the outer peripheral surface of the rotor magnet. An explanatory diagram three-dimensionally shown on the coordinates, an explanatory diagram showing an expanded magnetic flux density in the first magnetized region of the rotor magnet, an explanatory diagram showing an expanded magnetic flux density in the non-magnetized region of the rotor magnet, and It is explanatory drawing which expand | deploys and shows the magnetic flux density in the 2nd magnetization area | region of a rotor magnet, As can be understood from these figures, in the conventional stepping motor, the 1st magnetization area | region 221 and the 2nd magnetization area | region are shown. In 222, the magnetic flux density shows a sine wave (shown by solid lines L221 ″ and L222 ″ in FIGS. 8B and 8D), but even in the non-magnetized region 223, the magnetic flux density shows a clear sine wave. (Figure 8 (c Are shown by a solid line L223), not in full Muchaku magnetized region. For this reason, the conventional stepping motor has a problem that it is impossible to reliably prevent the generation of vibration and noise. The reason is, for example, as shown in FIG. 7, when the nonmagnetic material 119 is inserted into the portion facing the central position in the axial direction of the rotor magnet 22, the first magnetizing yoke 111, the nonmagnetic material 119, Two magnetizing yokes 112 are laminated to form the magnetizing yoke 11, and the adjacent magnetizing coils 15 (shown by alternate long and short dash lines) are joined at the other end while being folded at one end in the axial direction. After tightening and connecting with solder 150 or the like, the magnetizing coil 15 passes through the portion where the non-magnetic material 119 is located. Therefore, the central region in the axial direction of the rotor magnet 22 cannot be made a complete non-magnetized region 223. it is conceivable that.

  Further, in the stepping motor, the positions of the N pole and the S pole may be shifted between the first magnetized region 221 and the second magnetized region 222 arranged in the axial direction of the rotor magnet 22. Can be manufactured by shifting the first magnetizing yoke 111 and the second magnetizing yoke 112 in the circumferential direction.

  However, in the magnetized yoke 11 shown in FIG. 7, the amount by which the first magnetized yoke 111 and the second magnetized yoke 112 can be shifted in the circumferential direction is not cut even when the magnetized coil 15 is tensioned. For example, the positions of the N pole and the S pole can be shifted by only 5 ° to 10 ° in electrical angle in the first magnetized region 221 and the second magnetized region 222.

  In view of the above problems, an object of the present invention is to provide a method of manufacturing a rotor magnet and a motor capable of suitably forming a predetermined magnetized region on the outer peripheral surface of the rotor magnet.

  In order to solve the above-described problems, in the present invention, a magnetizing coil provided in the magnetizing yoke is energized in a state in which a rotor magnet before magnetizing is inserted into an insertion hole formed in the axial direction of the magnetizing yoke. Thus, in the method of manufacturing a rotor magnet for magnetizing the outer peripheral surface of the rotor magnet, the magnetizing coil includes a first magnetizing coil provided in one region in the axial direction of the magnetizing yoke, and the magnetizing coil. A second magnetizing coil provided on the other side region in the axial direction of the magnetic yoke, and a first magnetized region located on one side in the axial direction on the outer peripheral surface of the rotor magnet, and the other in the axial direction. And a second magnetized region located on the side.

  In the present invention, as the magnetizing coil, a first magnetizing coil provided in one side region in the axial direction of the magnetizing yoke, and a second magnetizing coil provided in the other region in the axial direction of the magnetizing yoke; Therefore, the outer peripheral surface of the rotor magnet can be magnetized independently by the first magnetizing coil and the second magnetizing coil. For this reason, a predetermined magnetization region can be suitably formed on the outer peripheral surface of the rotor magnet.

  In the present invention, it is preferable to use a yoke obtained by dividing the magnetizing yoke into a first magnetizing yoke constituting the one side region and a second magnetizing yoke constituting the other side region.

  In the present invention, in order to form a non-magnetized region between the first magnetized region and the second magnetized region between the one side region and the other side region of the magnetized yoke. It is preferable to constitute the nonmagnetic region. In the present invention, the “non-magnetic region” means a region where no magnetic flux is generated, or even if magnetic flux is generated, the density thereof is extremely low, and thus there is no magnetizing ability for the rotor magnet. In the present invention, the “non-magnetized region” means that a magnetic flux is hardly generated and a motor in which the first stator core and the second stator core are arranged so as to overlap each other in the motor axial direction is used. This means a region where the magnetic flux does not converge at the contact portion with the stator core. In a motor using a rotor magnet manufactured by such a method, even when the first stator core and the second stator core are in contact, the magnetic flux from the rotor magnet does not converge at such a contact portion. Therefore, no large detent torque that prevents the rotation of the rotor magnet is generated, so that no vibration or noise is generated.

  In the present invention, the nonmagnetic region can be constituted by, for example, an annular recess that is recessed outward in the radial direction on the inner peripheral surface of the magnetized yoke.

  In the present invention, the first magnetized coil and the second magnetized coil are arranged such that the positions of the N pole and the S pole are shifted from each other by a predetermined electrical angle between the first magnetized region and the second magnetized region. It is preferable to set the position and energization direction of the magnetizing coil. That is, in the present invention, the positions and energization directions of the first magnetizing coil and the second magnetizing coil can be arbitrarily set, so that between the first magnetizing region and the second magnetizing region. The positions and energization directions of the first magnetizing coil and the second magnetizing coil can be set so that the positions of the N pole and the S pole are shifted by 180 ° in electrical angle. If comprised in this way, the rotation direction of a rotor will be made opposite with respect to the case where the position of a north pole and a south pole is in agreement between a said 1st magnetization area | region and a said 2nd magnetization area | region. be able to.

  In the present invention, it is preferable that the rotor magnet has a cylindrical shape having a constant outer diameter from at least the first magnetized region to the second magnetized region. According to the present invention, when magnetizing, a region that can be said to be a completely non-magnetized region can be formed between the first magnetized region and the second magnetized region. Those having a cylindrical shape with a constant dimension can be used, and such a rotor magnet can be formed with a material that is inexpensive and excellent in magnetic performance.

  In order to configure a motor using the rotor magnet according to the present invention, a first stator core having pole teeth facing the first magnetized region and the second attachment around the rotor magnet. A cylindrical stator is disposed in which a second stator core having pole teeth facing the magnetic region is disposed so as to overlap in the motor axial direction.

  In the present invention, a rotor provided with a cylindrical stator provided with a first stator core and a second stator core arranged so as to overlap in the motor axial direction, and a rotor magnet whose outer peripheral surface faces the inner peripheral surface of the stator. The rotor magnet has a cylindrical shape whose outer diameter dimension is constant in the axial direction, and a first outer surface of the rotor magnet facing the pole teeth of the first stator core. And a second magnetized region opposite to the pole teeth of the second stator core are formed, and there is no gap between the first magnetized region and the second magnetized region. A magnetized region is formed.

  In the present invention, a rotor provided with a cylindrical stator provided with a first stator core and a second stator core arranged so as to overlap in the motor axial direction, and a rotor magnet whose outer peripheral surface faces the inner peripheral surface of the stator. And a second magnetized region facing the pole teeth of the first stator core and the second magnetized region facing the pole teeth of the second stator core on the outer peripheral surface of the rotor magnet. And the first and second magnetized regions are characterized in that the positions of the N pole and the S pole are deviated from each other by a predetermined angle, for example, 180 °.

  In the present invention, as the magnetizing coil, a first magnetizing coil provided in one side region in the axial direction of the magnetizing yoke, and a second magnetizing coil provided in the other region in the axial direction of the magnetizing yoke; Therefore, the outer peripheral surface of the rotor magnet can be magnetized independently by the first magnetizing coil and the second magnetizing coil. For this reason, a predetermined magnetization region can be suitably formed on the outer peripheral surface of the rotor magnet.

  A rotor magnet manufacturing method and a stepping motor to which the present invention is applied will be described below with reference to the drawings.

[Embodiment 1]
FIG. 1 and FIG. 2 are a longitudinal sectional view of a stepping motor to which the present invention is applied, and an explanatory view showing an exploded main part of the stepping motor.

  As shown in FIGS. 1 and 2, the stepping motor 1 of this embodiment is a PM type stepping motor, and includes a rotor magnet 22 made of a cylindrical permanent magnet and a rotor 2 having a rotating shaft 21 extending from the rotor magnet 22. And a cylindrical stator 3 arranged so as to surround the rotor magnet 22. The rotor magnet 22 is configured on the base end side (opposite output end side) with respect to the rotation shaft 21 and has a configuration in which the output end side protrudes greatly.

  The stator 3 includes a first stator set 4 and a second stator set 5 that are arranged so as to overlap in the motor axial direction. Among these stator sets 4 and 5, the first stator set 4 located on the distal end side includes a first outer stator core 41, a first bobbin 42 around which a coil is wound, and this bobbin 42 as a first. The first inner stator core 43 is sandwiched between the first outer stator core 41 and the first inner stator core 43 along the inner peripheral surface of the first bobbin 42. The plurality of formed pole teeth 411 and 431 are arranged. Similarly, the second stator set 5 located on the base end side also includes a second outer stator core 51, a second bobbin 52 around which a coil is wound, and the bobbin 52 with the second outer stator core 51. And a plurality of poles formed on each of the second outer stator core 51 and the second inner stator core 53 along the inner peripheral surface of the second bobbin 52. Teeth 511 and 531 are arranged. Here, the first stator set 4 and the second stator set 5 have a two-phase structure in which the electrical angle is shifted by 90 °.

  The first and second bobbins 42 and 52 are both resin molded products, and cylindrical body portions 422 and 522 around which the coil windings 421 and 521 are wound, and upper ends of the cylindrical body portions 422 and 522 And flange portions 423, 424, 523, and 524 formed on the side and the lower end side.

  Here, the first stator set 4 and the second stator set 5 are directly overlapped, and the first inner stator core 43 and the second inner stator core 53 are in direct contact with each other at the contact portion 30. The first inner stator core 43 and the second inner stator core 53 may be joined by welding or the like.

  The distal end side (not shown) of the rotating shaft 21 is fixed to a U-shaped mounting plate 8 fixed to the stator 3, while the proximal end side of the rotating shaft 21 is supported by the radial bearing 7. Yes. The radial bearing 7 is fitted and fixed to the inner peripheral surface of the second inner stator core 53 constituting the second stator set 5. The radial bearing 7 is fixed by an end plate 6. A recess 26 into which the radial bearing portion 7 enters around the rotation shaft 21 is formed on the base end surface of the rotor magnet 22, and a recess 27 is formed around the rotation shaft 21 on the distal end surface.

(Detailed configuration of rotor magnet)
3A, 3B, 3C and 3D show the results of measuring the magnetic flux density of the outer peripheral surface of the rotor magnet used in the stepping motor according to Embodiment 1 of the present invention. Explanatory view three-dimensionally on the coordinates where the surface is developed, an explanatory view showing the magnetic flux density in the first magnetized region of the rotor magnet, and an expanded view showing the magnetic flux density in the non-magnetized region of the rotor magnet It is explanatory drawing and explanatory drawing which expand | deploys and shows the magnetic flux density in the 2nd magnetization area | region of a rotor magnet.

  In the stepping motor 1 configured as described above, in this embodiment, the rotor magnet 22 has a cylindrical shape whose outer diameter dimension is constant in the axial direction. Further, on the outer peripheral surface of the rotor magnet 22, a first magnetized region 221 that faces the pole teeth 411 and 431 of the first outer stator core 41 and the first inner stator core 43 in one axial region, And a second magnetized region 222 facing the pole teeth 511 and 531 of the second outer stator core 51 and the second inner stator core 53 in the other axial region. Further, the outer peripheral surface of the rotor magnet 22 is opposed to the contact portion 30 between the first inner stator core 43 and the second inner stator core 53 between the first magnetized region 221 and the second magnetized region 222. A non-magnetized region 223 is formed in the region to be operated.

  If the result of measuring the magnetic flux density on the outer peripheral surface of the rotor magnet 22 configured as described above is three-dimensionally shown on the coordinates where the outer peripheral surface of the rotor magnet is developed, it appears as shown in FIG. That is, as indicated by solid lines L221 and L222 in FIGS. 3B and 3D, the first magnetized region 221 and the second magnetized region 222 have N and S poles alternately in the circumferential direction. It is a multi-pole magnetized region. Further, as indicated by a solid line L223 in FIG. 3C, the non-magnetized region 223 has a magnetic flux density that is so low that almost no magnetic flux can be detected. The magnetic flux is not converged on the region facing the portion 30. Therefore, since no large detent torque that prevents the rotor magnet 22 from rotating is generated, no vibration or noise is generated in the stepping motor 1 of this embodiment.

  Further, the rotor magnet 22 has a cylindrical shape with a constant outer diameter in the entire axial direction. With such a rotor magnet 22, it can be formed with a material that is inexpensive and has excellent magnetic performance.

(Method for manufacturing rotor magnet 22)
4A to 4G are cross-sectional views of a magnetizing apparatus used in the manufacturing method of the present embodiment, a plan view of the magnetizing yoke, a bottom view of the magnetizing yoke, and a rotor magnet in the insertion hole of the magnetizing yoke. Sectional drawing which expands and shows the state which inserted A, the perspective view which expands the internal peripheral surface of a magnetizing yoke, the equivalent circuit diagram when the 1st magnetizing coil and the 2nd magnetizing coil are connected in series, It is an equivalent circuit diagram when the first magnetizing coil and the second magnetizing coil are connected in parallel.

  Next, of the manufacturing method of the rotor magnet 22, a step of magnetizing the unmagnetized rotor magnet 22 formed by molding a magnetic material will be described.

  In this embodiment, as shown in FIGS. 4A to 4E, as the magnetizing apparatus 10, a first magnetizing coil 151 and a second magnetizing coil 152 are provided in one side region and the other side region, respectively. The magnetized yoke 11 is used. Since the insertion hole 130 is formed in the magnetizing yoke 11 in the axial direction, the first magnetizing coil 151 and the second magnetizing coil 151 are inserted with the rotor magnet 22 before magnetization inserted into the insertion hole 130. By energizing the magnetizing coil 152, the outer peripheral surface of the rotor magnet 22 can be magnetized.

  In carrying out such a magnetizing step, in this embodiment, as the magnetizing yoke 11, the first magnetizing yoke 111 constituting the one side region where the first magnetizing coil 151 is provided, and the second magnetizing. A yoke divided into the second magnetized yoke 112 constituting the other side region provided with the coil 152 is used. Here, the first magnetizing yoke 111 and the second magnetizing yoke 112 are formed with holes 131 and 132 constituting the insertion hole 130 when they are overlapped in the axial direction. On the inner peripheral surfaces of the holes 131 and 132 of the yoke 111 and the second magnetizing yoke 112, a plurality of coil wire placement grooves 161 and 162 extending in the axial direction and reaching both ends are equiangularly spaced in the circumferential direction. Is formed. In addition, the first magnetizing coil 151 is folded at the inner end with respect to the first magnetizing yoke 111, and the adjacent coils are crimped at the outer end, and then connected by solder 150 or the like. The second magnetizing coil 152 is folded back at the inner end with respect to the second magnetizing yoke 112, and the adjacent coils are crimped at the opposite end, and then solder (not shown) Etc. are connected. Feed lines 171 and 172 having terminals are drawn out from the first magnetizing coil 151 and the second magnetizing coil 152, and the first magnetizing coil 151 and the second magnetizing coil 152 are As shown in FIGS. 4F and 4G, power is supplied in a state of being connected in series or in a state of being connected in parallel. The first magnetizing coil 151 and the second magnetizing coil 152 may be folded at both ends of the first magnetizing yoke 111 and the second magnetizing yoke 112, respectively.

  Further, in this embodiment, arc-shaped step portions 141 and 142 are formed at a portion where the first magnetizing yoke 111 (one side region) and the second magnetizing yoke 112 (the other side region) are in contact with each other. When the first magnetizing yoke 111 and the second magnetizing yoke 112 are overlapped in the axial direction, these step portions 141 and 142 are integrated into the inner peripheral surface of the magnetizing yoke 11 with a radius. An annular recess 140 that is recessed outward is formed. Therefore, a magnetic flux is not generated by the annular recess 140 on the inner peripheral surface of the magnetized yoke 11, or a non-magnetic region having a remarkable density is formed even when the magnetic flux is generated.

  In the magnetizing device 10 having such a configuration, when the first magnetizing coil 151 and the second magnetizing coil 152 are energized with the rotor magnet 22 before magnetizing inserted into the insertion hole 130, the rotor magnet 22 is energized. The first magnetized region 221 in which N poles and S poles are alternately formed in the circumferential direction is formed in the one side region facing the first magnetizing yoke 111 of the outer peripheral surface of the second magnetized surface. A second magnetized region 222 in which N poles and S poles are alternately formed in the circumferential direction is formed in the other region facing the magnetic yoke 112.

  Here, in the first magnetizing coil 151 and the second magnetizing coil 152, a current in the same direction flows through a portion overlapping in the axial direction. Accordingly, in the first magnetized region 221 and the second magnetized region 222 of the rotor magnet 22, the same magnetic pole is formed at a position overlapping in the axial direction, and there is no deviation in electrical angle.

  In addition, a portion of the outer peripheral surface of the rotor magnet 22 facing the annular recess 140 is not magnetized, and a non-magnetized region 223 is formed between the first magnetized region 221 and the second magnetized region 222. It is formed. Moreover, in this embodiment, since the two magnetized coils 151 and 152 are used, the magnetized coil does not pass through the portion corresponding to the annular recess 140. Therefore, a substantially complete non-magnetized region 223 can be formed.

  As described above, according to the present embodiment, the non-magnetized region 223 can be easily formed in the cylindrical rotor magnet 22 having a constant outer diameter dimension in the entire axial direction, and such a non-magnetized region 223 is formed. Is a completely non-magnetized region in which almost no magnetic flux is generated, so that even when the stepping motor 1 in which the two stator sets 4 and 5 are superposed in the motor axial direction is configured, the first inner stator core 43 and The magnetic flux is not converged on the contact portion 30 with the second inner stator core 53.

[Embodiment 2]
5A, 5B, 5C, and 5D show the results of measuring the magnetic flux density on the outer peripheral surface of the rotor magnet used in the stepping motor according to Embodiment 2 of the present invention. Explanatory view three-dimensionally on the coordinates where the surface is developed, an explanatory view showing the magnetic flux density in the first magnetized region of the rotor magnet, and an expanded view showing the magnetic flux density in the non-magnetized region of the rotor magnet It is explanatory drawing and explanatory drawing which expand | deploys and shows the magnetic flux density in the 2nd magnetization area | region of a rotor magnet.

  In the first embodiment, when the rotor magnet 22 is magnetized, a current in the same direction is passed through the first magnetizing coil 151 and the second magnetizing coil 152 in the overlapping portion in the axial direction. By changing the connection between the first magnetized coil 151 and the second magnetized coil 152, the current in the direction opposite to the axially overlapping portion of the first magnetized coil 151 and the second magnetized coil 152 As shown in FIGS. 5A, 5 </ b> B, 5 </ b> C, and 5 </ b> D, the first magnetized region 221 and the second magnetized region 222 of the rotor magnet 22 are axially aligned. Different magnetic poles are formed at the overlapping positions. Therefore, in the first magnetized region 221 and the second magnetized region 222, as indicated by solid lines L221 ′ and L222 ′ in FIGS. Thus, the rotor magnet 22 that is shifted by 180 ° can be manufactured. If such a rotor magnet 22 is used, the stepping motor 1 in which the rotor 2 rotates in the direction opposite to that of the first embodiment can be configured.

  In the present embodiment, as in the first embodiment, since the annular recess 140 (nonmagnetic region) is provided in the portion where the first magnetized yoke 111 and the second magnetized yoke 112 are in contact with each other, FIG. As shown by a solid line L223 ′, a non-magnetized region 223 is formed between the first magnetized region 221 and the second magnetized region 222. However, the first magnetized region 221 and the second magnetized region When the positions of the N pole and the S pole need only be shifted by 180 ° in the electrical angle in the magnetized region 222, the annular recess 40 is formed from the portion where the first magnetized yoke 111 and the second magnetized yoke 112 are in contact with each other. (Nonmagnetic region) may be omitted.

[Other embodiments]
In the above embodiment, the first magnetizing coil 151 is arranged in one side region in the axial direction of the magnetizing yoke 11, and the second magnetizing coil 152 is arranged in the other region in the axial direction of the magnetizing yoke 11. In order to facilitate the placement of the magnetizing coils 151 and 152, the magnetizing yoke 11 is divided into two magnetizing yokes 111 and 112. A magnetized yoke 11 may be used.

  In the above embodiment, the annular recess 40 is formed when the nonmagnetic region is formed in the magnetized yoke 11. However, as described with reference to FIG. A nonmagnetic material 119 may be disposed between the magnetized yoke 112.

  Further, in the second embodiment, the first magnetizing coil 151 is configured such that the positions of the N pole and the S pole are shifted by 180 ° in electrical angle between the first magnetized region 221 and the second magnetized region 222. The position and energization direction of the second magnetizing coil 152 are set, but the deviation angle is not limited to 180 ° in electrical angle, but may be set to any electrical angle, for example, 90 ° or 270 ° in electrical angle. The positions and energization directions of the first magnetizing coil 151 and the second magnetizing coil 152 may be set.

It is a longitudinal cross-sectional view of the stepping motor to which this invention is applied. It is a longitudinal cross-sectional view of the stepping motor to which this invention is applied, and explanatory drawing which decomposes | disassembles and shows the principal part of a stepping motor. (A), (b), (c), (d) shows the result of measuring the magnetic flux density of the outer peripheral surface of the rotor magnet used in the stepping motor according to the first embodiment of the present invention on the outer peripheral surface of the rotor magnet. Explanatory view shown three-dimensionally on the developed coordinates, an explanatory view showing the magnetic flux density in the first magnetized region of the rotor magnet, and an explanatory diagram showing the magnetic flux density in the non-magnetized region of the rotor magnet developed FIG. 5 is an explanatory view showing a developed magnetic flux density in a second magnetized region of the rotor magnet. (A) to (g) are a sectional view of a magnetizing device used in the manufacturing method of the present embodiment, a plan view of the magnetizing yoke, a bottom view of the magnetizing yoke, and a rotor magnet inserted into the insertion hole of the magnetizing yoke. FIG. 5 is a cross-sectional view showing the enlarged state, a perspective view showing the inner peripheral surface of the magnetizing yoke in an enlarged manner, an equivalent circuit diagram when the first magnetizing coil and the second magnetizing coil are connected in series, and It is an equivalent circuit diagram when the 1 magnetizing coil and the 2nd magnetizing coil are connected in parallel. (A), (b), (c), (d) shows the result of measuring the magnetic flux density of the outer peripheral surface of the rotor magnet used in the stepping motor according to the second embodiment of the present invention on the outer peripheral surface of the rotor magnet. Explanatory view shown three-dimensionally on the developed coordinates, an explanatory view showing the magnetic flux density in the first magnetized region of the rotor magnet, and an explanatory diagram showing the magnetic flux density in the non-magnetized region of the rotor magnet developed FIG. 5 is an explanatory view showing a developed magnetic flux density in a second magnetized region of the rotor magnet. (A), (b) is a longitudinal cross-sectional view of the conventional stepping motor. It is explanatory drawing of the conventional magnetizing apparatus. (A), (b), (c), (d) are three-dimensional results obtained by measuring the magnetic flux density of the outer peripheral surface of the rotor magnet used in the conventional stepping motor on the coordinates where the outer peripheral surface of the rotor magnet is developed. FIG. 2 is an explanatory diagram illustrating the magnetic flux density in the first magnetized region of the rotor magnet, FIG. 2 is an explanatory diagram illustrating the magnetic flux density in the non-magnetized region of the rotor magnet, and the second of the rotor magnet. It is explanatory drawing which expand | deploys and shows the magnetic flux density in the magnetization area | region.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stepping motor 22 Rotor magnet 21 Rotating shaft 2 Rotor 3 Stator 4 1st stator set 5 2nd stator set 10 Magnetizing apparatus 11 Magnetizing yoke 30 Contact part 41 of inner stator cores 41 1st outer stator core 43 1st Inner stator core 51 Second outer stator core 53 Second inner stator core 111 First magnetized yoke 112 Second magnetized yoke 140 Annular recess (nonmagnetic region)
151 First magnetized coil 152 Second magnetized coil 130 Insertion holes 161 and 162 Magnetized yoke groove 221 First magnetized region 222 Second magnetized region 223 Non-magnetized regions 411, 431, 511, 531 pole teeth

Claims (11)

By energizing the magnetizing coil provided in the magnetizing yoke with the rotor magnet before magnetizing inserted into the insertion hole formed in the axial direction of the magnetizing yoke, the outer peripheral surface of the rotor magnet is magnetized. In the manufacturing method of the rotor magnet to be applied,
As the magnetizing coil, a first magnetizing coil provided in one side region in the axial direction of the magnetizing yoke and a second magnetizing coil provided in the other region in the axial direction of the magnetizing yoke And a first magnetized region located on one side in the axial direction and a second magnetized region located on the other side in the axial direction are formed on the outer peripheral surface of the rotor magnet. Magnet manufacturing method.   2. The yoke according to claim 1, wherein the magnetized yoke is divided into a first magnetized yoke constituting the one side region and a second magnetized yoke constituting the other side region. To manufacture a rotor magnet.   3. The non-magnetized region is formed between the first magnetized region and the second magnetized region between the one side region and the other side region of the magnetized yoke. A non-magnetic region for forming a rotor magnet is provided.   4. The method of manufacturing a rotor magnet according to claim 3, wherein the nonmagnetic region is an annular recess that is recessed radially outward on an inner peripheral surface of the magnetized yoke.   5. The first magnetization according to claim 1, wherein the positions of the N pole and the S pole are deviated from each other by a predetermined electrical angle between the first magnetization area and the second magnetization area. A method of manufacturing a rotor magnet, comprising setting a position of a coil and a second magnetizing coil and a direction of energization.   6. The first magnetized coil and the first magnetized coil according to claim 5, wherein the positions of the N pole and the S pole are shifted by 180 degrees in electrical angle between the first magnetized region and the second magnetized region. A method of manufacturing a rotor magnet, comprising setting a position and an energization direction of two magnetizing coils.   7. The rotor magnet according to claim 1, wherein the rotor magnet includes at least one magnet having a cylindrical shape with a constant outer diameter from the first magnetized region to the second magnetized region. A method for manufacturing a rotor magnet. A motor having a rotor magnet manufactured by the method of manufacturing a rotor magnet according to any one of claims 1 to 7,
Around the rotor magnet, there are a first stator core having pole teeth facing the first magnetized region and a second stator core having pole teeth facing the second magnetized region. A motor having a cylindrical stator arranged in an overlapping manner in the motor axial direction. A motor having a cylindrical stator provided with a first stator core and a second stator core arranged so as to overlap in the motor axial direction, and a rotor provided with a rotor magnet whose outer peripheral surface faces the inner peripheral surface of the stator In
The rotor magnet has a cylindrical shape whose outer diameter dimension is constant in the axial direction,
A first magnetized region facing the pole teeth of the first stator core and a second magnetized region facing the pole teeth of the second stator core are formed on the outer peripheral surface of the rotor magnet. In addition, a non-magnetized region is formed between the first magnetized region and the second magnetized region. A motor having a cylindrical stator provided with a first stator core and a second stator core arranged so as to overlap in the motor axial direction, and a rotor provided with a rotor magnet whose outer peripheral surface faces the inner peripheral surface of the stator In
On the outer peripheral surface of the rotor magnet, a first magnetized region facing the pole teeth of the first stator core and a second magnetized region facing the pole teeth of the second stator core are formed,
The motor characterized in that the first magnetized region and the second magnetized region are deviated from each other by a predetermined electrical angle between the N pole and the S pole.   11. The motor according to claim 10, wherein the first magnetized region and the second magnetized region are shifted from each other by 180 degrees in electrical angle between the N pole and the S pole.

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