JP2011030314A - Ring magnet, motor and electrical apparatus including the same, and method of forming the ring magnet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain magnetic characteristics suitable for each of drive and FG in hollow cylindrical ring magnets. <P>SOLUTION: A magnet includes a main magnetization section 23m, that includes a magnetic material for the main and is subjected to main magnetization having alternately opposite poles in a peripheral direction, and an FG magnetization section 23f, that includes a magnetic material for FG and is subjected to FG magnetization alternately having larger opposite poles, in a peripheral direction than the main magnetization section 23m. The main magnetization section 23m and the FG magnetization section 23f are disposed so that the layers of the main magnetization section 23m and the FG magnetization section 23f are formed, in a direction going from one end to the other end. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a ring magnet mounted on a motor, a motor including the ring magnet, an electric device including the motor, and a method of forming the ring magnet, and in particular, detects a position and a speed together with magnetization for driving the motor. The present invention relates to a ring magnet that has been magnetized, a motor and an electric device including the ring magnet, and a method of forming the ring magnet.

  In recent years, for example, there is a brushless DC motor as one of motors mounted on electric devices. Such a brushless DC motor generally has a function of detecting a rotational speed and a rotational position. As a means for detecting the rotational speed, a speed generator utilizing a power generator function called a frequency generator or FG for short is widely used. In order to generate a power generation signal for speed detection (hereinafter referred to as FG signal) in the frequency generator, for example, a magnetic pattern for power generation is magnetized on the magnet of the rotor (hereinafter referred to as FG magnetization). Has been. Then, an FG pattern constituted by a zigzag wiring pattern or the like for outputting an FG signal is arranged opposite to the FG magnetization.

  By the way, when such an FG magnetized part is close to the main magnetized part for driving the motor or the iron core of the stator, the frequency generator is affected by the main magnetized or the magnetism generated from the iron core. It becomes easy. And these magnetism may become noise and there exists a possibility that the detection accuracy of rotational speed may deteriorate.

  For this reason, for the purpose of improving the detection accuracy of the rotational speed and position, for example, a technique such as Patent Document 1 has been proposed. In Patent Document 1, a driving magnet is provided with a protruding portion that protrudes from the lower end surface of the rotor holder, and a rotation detecting magnet such as a rotation speed and position is further attached to the outer peripheral surface of the protruding portion. FG magnetization is applied to the lower end surface of the rotation detection magnet. As a result, the distance between the FG magnetization and the drive magnetization is increased, so that the frequency generator is less susceptible to magnetic influence from the drive magnetization, and the accuracy of speed detection reading is improved.

  On the other hand, as in Patent Document 1, the configuration in which the drive magnet and the rotation detection magnet are individually provided have problems such as an increase in the number of parts and the number of assembly steps. For this reason, conventionally, as in Patent Document 2, for example, a technique has been proposed in which driving magnetism and FG magnetization are applied to one magnet. Patent Document 2 discloses a flexible magnet obtained by kneading a magnetic material in a binder such as rubber as a magnet for a motor. This flexible magnet is curled in an annular shape, and is magnetized for driving on the peripheral side surface portion, and FG magnetized on the end surface portion, and is mounted on the motor. According to such a configuration, since the magnetic patterns for driving and FG can be obtained with one magnet, the number of parts and the number of assembling steps can be reduced.

JP 2006-314165 A Japanese Patent No. 2541536

  However, the flexible magnet of Patent Document 2 has a shorter distance between the FG magnetization and the drive magnetization than the configuration of Patent Document 1, so the frequency generator is It becomes susceptible to magnetic effects.

  Furthermore, since the flexible magnet of Patent Document 2 is formed to include only one type of magnetic material, there is a problem that optimal magnetic characteristics cannot always be obtained for each of driving and FG. It was. That is, it is preferable that a large driving force is obtained as a driving magnet. On the other hand, since the frequency generator can detect the rotational speed and the like with higher accuracy as the frequency of the FG signal is higher, a magnet suitable for forming a narrow magnetization pitch is preferable as the FG magnet. Along with such a large driving force, there is a limit to realizing a narrow magnetization pitch with one kind of magnetic material. As an example, in recent years, magnets with high coercive force have been used for high heat resistance. On the other hand, such magnets have poor magnetizing performance and are not suitable for forming narrow magnetization pitches. Become.

  The present invention has been made to solve such problems, and in a magnet having a single hollow cylindrical shape, a ring magnet capable of obtaining magnetic characteristics suitable for driving and for FG respectively, It is an object of the present invention to provide a motor and an electric device provided, and a method for forming a ring magnet.

  In order to achieve the above object, a ring magnet of the present invention has a hollow cylindrical shape with both ends opened, and is a ring magnet mounted on a motor, including a first magnetic material, and alternately in a circumferential direction. A second magnetizing that includes a first magnet part having a first magnetization having a different polarity and a second magnetic material, and has a different polarity alternately in the circumferential direction more than the first magnetization. The first magnet part and the second magnet part are provided with a first magnet part layer and a second magnet part layer in the direction from one end to the other end. It is the structure arrange | positioned so that may be formed.

  With this configuration, a first magnetic material suitable for driving is used for the first magnet part, and a second magnetic material suitable for FG is used for the second magnet part. Thus, it is possible to individually obtain magnetic characteristics according to the purpose. For this reason, for example, the first magnet part uses the first magnetic material that can obtain a high driving output to increase the output, and the second magnet part has a second magnetic material with good magnetization performance. By using this, it becomes possible to form a narrow magnetization pitch.

  Moreover, the ring magnet of this invention is the structure by which the 1st magnet part and the 2nd magnet part were continuously formed in the other end direction from the one end.

  With this configuration, since the first magnet portion and the second magnet portion are formed as one integrated magnet, it is possible to reduce the number of motor parts and assembly man-hours.

  In addition, the ring magnet of the present invention is a bonded magnet in which each of the first magnet portion and the second magnet portion is obtained by bonding the respective magnetic materials with a resin as a binder.

  Further, in the ring magnet of the present invention, the first magnet portion and the second magnet portion are respectively coupled with resin.

  The ring magnet of the present invention includes a first magnetic material in which the first magnet portion is bonded with resin, and a second magnetic material in which the second magnet portion is bonded with resin. The one magnet part and the second magnet part are integrally formed through a resin binder to form a hollow cylindrical shape.

  With this configuration, since the first magnet portion and the second magnet portion are integrally formed of resin, sufficient binding strength is obtained compared to a magnet in which both magnet portions are bonded with an adhesive or the like. Can be secured. In addition, even if the usage environment such as temperature change changes, the difference in dimensional change between the first magnet portion and the second magnet portion can be reduced, so that damage due to a difference in thermal expansion can be suppressed.

  In the ring magnet of the present invention, the first magnetic material is an isotropic magnet powder, and the second magnetic material is an isotropic magnet powder having magnetic characteristics different from those of the first magnetic material.

  In the ring magnet of the present invention, the second magnetic material has at least one of a magnetic characteristic having a small coercive force and a magnetic characteristic having a high saturation magnetic flux density as compared with the first magnetic material. .

  With this configuration, the second magnet portion can have magnetic characteristics with good magnetization performance, a narrow magnetization pitch can be formed, and sufficient reading accuracy for speed detection can be obtained.

  In the ring magnet of the present invention, the first magnetic material may be anisotropic magnet powder, and the second magnetic material may be isotropic magnet powder.

  In the ring magnet of the present invention, the first magnetic material may be an isotropic magnet powder, and the second magnetic material may be an anisotropic magnet powder.

  In the ring magnet of the present invention, the first magnetic material may be anisotropic magnet powder, and the second magnetic material may be anisotropic magnet powder.

  With these configurations, the first magnet portion and the second magnet portion can be individually provided with magnetic characteristics according to the purpose.

  Moreover, the motor of this invention is the structure provided with the rotor containing the ring magnet mentioned above.

  With this configuration, magnetic characteristics suitable for driving and for FG can be obtained, so that a high-output motor with good rotation accuracy can be obtained.

  Moreover, the electric device of the present invention has a configuration including the motor described above.

  With this configuration, an accurate electrical device can be obtained.

  The ring magnet forming method of the present invention is the above-described ring magnet forming method, and the mold is filled with granules produced by kneading the magnetic powder, which is the second magnetic material, and resin. The first step, the second step of filling the mold with the granules produced by kneading the magnetic powder, which is the first magnetic material, and the resin, and compressing the filling material filled in the mold And a third step of forming a molded body.

  The ring magnet forming method of the present invention is the above-described ring magnet forming method, and the mold is filled with granules produced by kneading the magnetic powder, which is the first magnetic material, and resin. 1st step, 2nd step of filling granule produced by kneading magnet powder and resin as second magnetic material into mold, and compressing filling material filled in mold And a third step of forming the molded body.

  According to such a ring magnet forming method, it is only necessary to change to the respective magnet powders in the first step and the second step, so that it is simple without adding many changes from the conventional manufacturing process. A ring magnet having desired magnetic properties can be produced by the manufacturing method. In addition, as for manufacturing equipment, conventional manufacturing equipment can be used.

  According to the ring magnet of the present invention, in a magnet having a single hollow cylindrical shape, magnetic characteristics according to the purpose can be set at a desired location, so that magnetic characteristics suitable for driving and FG can be obtained. Can be provided. In addition, since the motor of the present invention includes such a ring magnet, a high-output motor with good rotation accuracy can be provided, and since the electric apparatus of the present invention includes such a motor, a highly accurate electric apparatus can be provided. In addition, according to the method for forming a ring magnet of the present invention, it is possible to provide a method for forming a ring magnet that can produce a ring magnet having desired magnetic characteristics by a simple manufacturing method.

Sectional drawing of the motor provided with the ring magnet which concerns on embodiment of this invention The external appearance perspective view of the magnet which concerns on embodiment of this invention The figure which shows each process of the formation method of the ring magnet which concerns on embodiment of this invention

  Hereinafter, a ring magnet according to an embodiment of the present invention, a motor and an electric device including the ring magnet, and a method for forming the ring magnet will be described with reference to the drawings.

(Embodiment)
FIG. 1 is a cross-sectional view of a motor provided with a ring magnet according to an embodiment of the present invention.

  First, the overall configuration of the motor will be described with reference to FIG. In the present embodiment, an example of an outer rotor type brushless DC motor will be described. Moreover, such a brushless DC motor is incorporated in an air conditioner or a printer as an electric device.

  As shown in FIG. 1, the motor according to the present embodiment includes a stator 10 and a rotor 20 that is arranged to face the stator 10 and to be rotatable on the outer peripheral side.

  The stator 10 includes a stator core 12 mounted on a wiring board 11. The stator core 12 is formed as a laminated body in which a plurality of plate-like bodies are laminated. A plurality of teeth as magnetic poles are arranged on the outer peripheral portion of the stator core 12 at predetermined intervals in the circumferential direction. Moreover, the coil 13 is wound around the arm part which comprises the magnetic circuit inside each teeth. In this way, the stator 10 in which the coil 13 is wound around the stator core 12 is configured. Further, the stator core 12 is fixed to the wiring board 11 via the housing 14. A bearing 15 is provided on the inner periphery of the housing 14. A rotating shaft 21 is disposed through the bearing 15 in the vertical direction. In the present embodiment, in the axial direction of the rotating shaft 21, that is, in the longitudinal direction, the side on which the stator 10 and the rotor 20 are mounted with respect to the wiring board 11 is described as being up, and vice versa.

  The rotor 20 includes the rotating shaft 21, the rotor frame 22, and a magnet 23. The rotor frame 22 is formed of a cylindrical magnetic body having an opening at one end side in the axial direction of the rotating shaft 21, that is, the lower side. Further, the upper end which is the other end side of the rotating shaft 21 is fixed to the rotor frame 22 at the center of the top surface of the rotor frame 22. A magnet 23, which is a ring magnet of the present embodiment, is attached to the inner peripheral side of the rotor frame 22 so as to be in direct contact with the inner peripheral side of the rotor frame 22. The magnet 23 is a ring magnet having a hollow cylindrical shape with both ends opened, that is, a ring shape.

  The magnet 23 has a main magnetized portion 23m in which the main magnetizing is performed on the inner periphery thereof, and an FG magnetizing is applied on the tip end face of the lower end portion of the magnet 23. It has an FG magnetized portion 23f. The main magnetized portion 23m includes the first magnetic material as the first magnet portion. The FG magnetized portion 23f includes a second magnetic material as a second magnet portion. As shown in FIG. 1, the main magnetized portion 23m and the FG magnetized portion 23f are arranged such that the main magnetized portion 23m and the FG magnetized portion 23f are arranged in the direction from one end to the other end, that is, from top to bottom. It arrange | positions so that a layer may be formed continuously.

  The main magnetized portion 23m is subjected to main magnetization as a first magnetization that is alternately different in the circumferential direction between the N pole and the S pole at every first predetermined interval. This main magnetization is magnetization for generating a rotational driving force. That is, by supplying an alternating current to the coil 13, magnetic fields of N and S poles are generated alternately from each tooth. Further, the teeth on the outer peripheral portion of the stator core 12 face the main magnetized portion 23 m on the inner periphery of the magnet 23. For this reason, an attractive force and a repulsive force are generated between the magnetic field from each tooth and the main magnetization of the magnet 23, and this becomes the rotational driving force of the rotor 20. Thus, the main magnetization is used for driving the motor.

  The FG magnetized portion 23f has more than the main magnetized at every second predetermined interval so that the magnetic pole pitch of the FG magnetizing as the second magnetizing is narrower than the magnetic pole pitch of the main magnetizing. This FG magnetization is performed in which the N poles and S poles are alternately different in the direction. FG magnetization is magnetization for speed detection as described above. That is, the FG magnetized portion 23f is magnetized with such a magnetic pattern in order to generate an FG signal for speed detection by power generation using magnetism.

  In this way, the magnet 23 is subjected to two types of magnetization, main magnetization and FG magnetization. That is, the motor of the present embodiment is equipped with a magnet 23 in which the driving and FG magnetic patterns are set as one magnet. Therefore, driving and speed detection can be performed with a simple configuration without increasing the number of parts.

  Further, in order to generate an FG signal from a magnetic pattern by FG magnetization, an FG pattern 24 is arranged on the wiring board 11 so as to face the FG magnetized portion 23 f at the lower end of the magnet 23. The FG pattern 24 is a wiring pattern in which, for example, zigzag wiring is formed in a ring shape on the wiring board 11. When the magnet 23 rotates with the rotation of the rotor 20, an electromotive force is generated from the FG pattern 24. This electromotive force includes a frequency component corresponding to the rotational speed of the rotor 20, and this electromotive force is output as an FG signal. Thus, the FG signal includes the rotational speed information and is used for controlling the rotational speed of the motor. In addition, as the frequency of the electromotive force is higher, the rotational position and rotational speed can be detected more finely. For this reason, by making the magnetization pitch of FG magnetization as narrow as possible, the rotation detection accuracy is increased, and the rotation accuracy of the motor can be increased.

  With the configuration as described above, an alternating current is supplied to the coil 13 to alternately generate N-pole and S-pole magnetic fields from each tooth, and the attractive force and repulsion between each tooth and the main magnetized portion 23m. Generate power. Then, the rotor 20 rotates about the rotation shaft 21, and the rotational force is transmitted to the load provided in the electric device via the rotation shaft 21.

  Next, the detail of the magnet 23 in this Embodiment is demonstrated.

  FIG. 2 is an external perspective view of the magnet 23 according to the embodiment of the present invention. As described above, the magnet 23 is arranged such that the main magnetized portion 23m and the FG magnetized portion 23f form respective layers. The main magnetized portion 23m is main magnetized including the first magnetic material, and the FG magnetized portion 23f is FG magnetized including the second magnetic material. In the present embodiment, a main magnetic material that is an isotropic metal magnetic powder suitable for obtaining a high driving torque is used as the first magnetic material, and the main magnetic material is used as the second magnetic material. An example using a magnetic material for FG, which is an isotropic metal magnetic powder having different magnetic characteristics from the above, will be described.

  In the present embodiment, the magnet 23 is a bonded magnet. The bond magnet is formed by kneading magnet powder and a resin serving as a binder thereof. That is, the metal magnetic powder, which is the magnetic material of the magnet 23, is bonded using a resin as a binder. Thus, in the magnet 23, the main magnetized portion 23m is formed by mixing the main magnetic material and the resin, and the FG magnetized portion 23f is formed by mixing the FG magnetic material and the resin.

The main magnetized portion 23m of the magnet 23 formed in this way is subjected to main magnetization for generating a rotational driving force as described above. Here, since the main magnetization directly affects the rotational driving force important for motor performance, the main magnetic material is preferably a material that can obtain a large driving force, for example. For this reason, as the main magnetic material, for example, a magnetic material having such a magnetic characteristic that a maximum energy product of 80 kJ / cm ³ can be obtained is preferable.

  On the other hand, as described above, the FG magnetization of the FG magnetized portion 23f is preferably made as narrow as possible in order to increase the rotation detection accuracy. However, if the magnetization pitch is to be narrowed, the winding diameter for passing a current through the magnetizing yoke must also be reduced, and the magnetizing current value becomes smaller. And it becomes difficult to obtain a magnetic field required for magnetization. For this reason, a magnetic signal can be recorded even with a small magnetization current by using a magnetic material for FG as a highly magnetized material. As the highly magnetized material, a material having at least one of magnetic characteristics having a small coercive force and a magnetic characteristic having a high saturation magnetic flux density as compared with the main magnetic material is suitable.

  Thus, the main magnetized portion 23m is a main magnetic material suitable for driving, and the FG magnetized portion 23f is an FG magnetic material suitable for FG having a narrow magnetization pitch. The magnet 23 can selectively set magnetic characteristics. For this reason, in the main magnetized portion 23m and the FG magnetized portion 23f, it is possible to individually obtain magnetic characteristics according to the purpose.

  In the present embodiment, the magnet 23 is integrally formed by using the same resin as the resin that binds the main magnetic material and the resin that binds the FG magnetic material. Here, as the resin, for example, a resin based on an epoxy resin is selected. In particular, in order to prevent breakage when the uncured product is cured after molding or when the magnet 23 is heated, the resin used is preferably a material having a value with a close linear expansion coefficient.

  By adopting such a configuration, the main magnetized portion 23m and the FG magnetized portion 23f are integrally formed of a resin, so that compared to a magnet in which both magnetized portions are bonded with an adhesive or the like. And sufficient bond strength can be secured. Moreover, since the expansion coefficients of both magnetized portions are close to each other, damage between the two magnetized portions due to heat can be suppressed.

  Next, a method of forming the magnet 23 that is the ring magnet of the present embodiment configured as described above will be described.

  FIG. 3 is a diagram showing each step of the ring magnet forming method according to the embodiment of the present invention. In order to form the magnet 23 which is a ring-shaped molded body, in this embodiment, as shown in FIG. 3, a mold 40 having a core 41, a die 42, a lower punch 44 and an upper punch 45 is used. Yes. A mold cavity 43 serving as a cylindrical space is formed between the core 41 and the die 42. The lower punch 44 and the upper punch 45 have a cylindrical shape and can be inserted into the mold cavity 43. In this forming method, roughly, after magnet powder and resin as materials before molding are kneaded, granules having the same particle diameter are filled into the mold cavity 43, and the filler is compressed to form a molded body. Form. Thereafter, the compression molded body is thermally cured to form a bonded magnet.

  Next, each process of the formation method of the magnet 23 is demonstrated, referring FIG.

  First, the metal magnetic powders of the main magnetic material and the FG magnetic material are individually mixed, kneaded, and dried with an epoxy resin to form granules so as to make the particle diameters uniform. At this time, the epoxy resin mixed with each metal magnetic powder is the same resin as described above. Further, the granule and the solid lubricant are mixed to prepare the main compound 30m and the FG compound 30f. Then, the created main compound 30m and FG compound 30f are put in a feeder box arranged on the upper side of the mold 40. On the other hand, the mold 40 is set at a predetermined position.

  Next, the lower punch 44 is lowered so that a space is formed above the mold cavity 43. Then, a feeder box containing the FG compound 30f is disposed, and as shown in FIG. 3A, the space formed in the upper part of the mold cavity 43 is filled with the FG compound 30f.

  Next, as shown in FIG. 3B, the lower punch 44 is further lowered to a predetermined position. At this time, as the lower punch 44 is lowered, the FG compound 30f is also lowered at the same time.

  Next, a feeder box containing the main compound 30m is arranged, and as shown in FIG. 3C, the space formed in the upper part of the mold cavity 43 is filled with the main compound 30m. When the filling is completed, the main compound 30m is overlaid on the FG compound 30f.

  Next, the upper punch 45 is set on the upper part of the mold cavity 43, and as shown in FIG. 3 (d), the compound, which is a filling material filled in the mold cavity 43, is applied with a predetermined surface pressure. The compound is compressed by pressing to form a molded body.

  Thereafter, the upper punch 45 is removed, and the lower punch 44 is raised to obtain a molded body 30 that becomes the magnet 23 on the upper part of the mold 40 as shown in FIG. In this way, the main magnetic material and the FG magnetic material are compressed in the mold 40 so that the two layers of the main magnetized portion 23m and the FG magnetized portion 23f are continuous. 30.

  Thereafter, the molded body 30 is subjected to surface rust prevention treatment and the like, and is further subjected to main magnetization. The molded body 30 is incorporated in the rotor frame 22 and fixed with an adhesive or the like. Thereafter, the end face of the molded body 30 is magnetized for FG, and the magnet 23 incorporated in the rotor frame 22 is completed. Since the magnet 23 to be created has a hollow cylindrical shape, the magnet 23 can be formed by such a simple forming method. Furthermore, since the hollow cylindrical magnet 23 has only to be incorporated into the rotor frame 22, the rotor 20 can be easily created.

  As described above, the magnet 23 is the main magnetic material for the first step of filling the mold 40 with granules produced by kneading magnet powder, which is a magnetic material for FG, and resin. A second step of filling the mold 40 with granules produced by kneading the magnet powder and the resin, and a third step of compressing the filler filled in the mold 40 to form a compact. Formed by a process including: According to such a ring magnet forming method of the present embodiment, it is only necessary to change to the respective magnetic powders in the first step and the second step, so that many changes are made from the conventional manufacturing process. Therefore, a ring magnet having desired magnetic properties can be produced by a simple manufacturing method. In addition, as for manufacturing equipment, conventional manufacturing equipment can be used.

  In the above description, an example in which the main magnetic material and the FG magnetic material are isotropic metal magnetic powders has been described, but one or each of them may be an anisotropic metal magnetic powder. Good.

  Further, as a method of forming the present ring magnet, the mold 40 is filled with granules produced by kneading the main magnetic material magnet powder and resin so that the above-described procedure of filling the granules is reversed. A first step, a second step of filling the mold 40 with granules produced by kneading magnet powder, which is a magnetic material for FG, and a resin, and a filling material filled in the mold 40. It may be a forming method formed by a process including a third step of forming a compact by compression.

  Next, examples in which isotropic and anisotropic metal magnetic powders are respectively combined as the main magnetic material and the FG magnetic material will be described.

Example 1
Each of the main magnetic material and the FG magnetic material was an isotropic metal magnetic powder having different magnetic properties. Using such a metal magnetic powder as a material, a bonded magnet was prepared by the process as shown in FIG. At this time, during compression as shown in FIG. 3 (d), the upper punch 45 was set and molded with a surface pressure of 10 ton / cm ² . Although the molded body has two layers, it could be molded without any problem in appearance. Further, since the resin agent and the amount of the resin are almost the same, no deformation or the like occurred between the main magnetized portion 23m and the FG magnetized portion 23f even after the uncured product was cured. Even after magnetization, there was no particular difference in strength.

  Regardless of the magnetic characteristics of the main magnetized portion 23m, the FG magnetized portion 23f can achieve the same rotational performance as the conventional one.

(Example 2)
Anisotropic metal magnetic powder was used as the main magnetic material, and isotropic metal magnetic powder was used as the magnetic material for FG. As in the case of Example 1, the binder resin was an epoxy resin for main use. The same epoxy resin was used for FG.

  Further, the mold was configured as the mold 40 as shown in FIG. Further, since an anisotropic material is used as the main magnetic material, an orientation magnetic field can be generated in the mold 40 in order to orient the anisotropic magnetic powder in the mold cavity 43. That is, in this embodiment, in order to make the best use of the characteristics of the anisotropic magnet, the anisotropic magnetic powder in the mold cavity 43 is oriented in a desired direction such as a radial direction or a pole concentration orientation direction by an orientation magnetic field. I am letting. In this embodiment, the anisotropic magnetic powder is oriented so as to be in an optimum direction by a magnetic field generated by a coil. A magnetic field generated by a permanent magnet may be used.

Then, in the same manner as in Example 1, after filling the FG compound 30f, the position of the lower punch 44 was further lowered, and the main compound 30m was filled and molding was performed. The molding pressure was 8 ton / cm ² .

  The main magnetized portion 23m of the cured molded body is subjected to main magnetization, and then fixed to the rotor frame 22 by adhesion or the like, and an FG pattern is magnetized to the FG magnetized portion 23f. Since the FG magnetized portion 23f is isotropic, the magnetizing conditions and the like were implemented under the same conditions as before.

  While securing rotational performance equivalent to that of the prior art by the FG magnetized portion 23f, high torque can be obtained because the main magnetized portion 23m is made of an anisotropic magnet and has a high magnetic force.

(Example 3)
An isotropic metal magnetic powder was used as the main magnetic material, and an anisotropic metal magnetic powder was used as the FG magnetic material. As in the case of Example 1, the binder resin was an epoxy resin for main use. The same epoxy resin was used for FG.

  Further, the mold was configured as the mold 40 as shown in FIG. Further, since the FG magnetized portion 23f uses an anisotropic material, it is performed in an orientation magnetic field. In order to perform FG magnetization, the orientation direction of the FG magnetized portion 23f was set to the axial direction. That is, since the FG pattern 24 is in the axial direction with respect to the magnet 23, the orientation direction of the FG magnetized portion 23f is set to the axial direction accordingly. For example, when the FG pattern 24 is arranged on the outer peripheral side from the magnet 23, the orientation direction of the FG magnetized portion 23f can be adjusted accordingly.

Then, in the same manner as in Example 1, after filling the FG compound 30f, the position of the lower punch 44 was further lowered, and the main compound 30m was filled and molding was performed. The molding pressure was 8 ton / cm ² .

  The main magnetized portion 23m of the cured molded body is subjected to main magnetization, and then fixed to the rotor frame 22 by adhesion or the like, and an FG pattern is magnetized to the FG magnetized portion 23f. Magnetization was performed under the same conditions as the conventional conditions. Here, since the FG magnetized portion 23f uses an oriented anisotropic magnet having high magnetic properties, it was possible to obtain a high signal strength as an FG signal. As a result, a motor with improved rotation control can be obtained.

Example 4
An anisotropic metal magnetic powder was used as the main magnetic material, and an anisotropic metal magnetic powder was used as the FG magnetic material. As in the case of Example 1, the binder resin was an epoxy resin for main use. The same epoxy resin was used for FG.

  Further, the mold was configured as the mold 40 as shown in FIG. Furthermore, since the main magnetized portion 23m and the FG magnetized portion 23f use anisotropic materials, an electromagnet for generating an orientation magnetic field is disposed in the mold 40. The magnetic field to be oriented may be generated by a permanent magnet.

  The main magnetized portion 23m of the cured molded body is subjected to main magnetization, and then fixed to the rotor frame 22 by adhesion or the like, and an FG pattern is magnetized to the FG magnetized portion 23f. Magnetization was performed under the same conditions as the conventional conditions. Also in this example, since the FG magnetized portion 23f is used by orienting an anisotropic magnet having high magnetic characteristics, a high signal strength can be obtained as an FG signal. As a result, a motor with improved rotation control can be obtained.

  As described above, the ring magnet of the present invention includes the first magnet portion including the first magnetic material, and has been subjected to the first magnetization having the different polarity in the circumferential direction, and the second magnetism. A second magnet portion including a material and having a second magnetizing portion that is alternately poled in the circumferential direction more than the first magnetizing portion, the first magnet portion and the second magnet portion Is arranged so that a layer of the first magnet part and a layer of the second magnet part are formed in the direction from one end to the other end. For this reason, the first magnet part can be selectively set using a first magnetic material suitable for driving and the second magnet part using a second magnetic material suitable for FG. Thus, it is possible to obtain magnetic characteristics according to the purpose individually. Therefore, according to the ring magnet of the present invention, it is possible to provide a ring magnet capable of obtaining magnetic characteristics suitable for driving and for FG. In addition, since the motor of the present invention includes such a ring magnet and the electric device of the present invention includes such a motor, it is possible to provide a high-precision motor with high accuracy and a high-precision electric device.

  The ring magnet forming method of the present invention includes a first step of filling a mold with granules produced by kneading a magnetic powder, which is a second magnetic material, and a resin, and the first magnetic material. A second step of filling the mold with granules produced by kneading the magnet powder and the resin, and a third step of compressing the filler filled in the mold to form a compact. including. The ring magnet forming method of the present invention can provide a ring magnet forming method capable of producing a ring magnet having desired magnetic characteristics by such a simple manufacturing method.

  According to the ring magnet of the present invention, magnetic characteristics suitable for driving and for FG can be obtained. Therefore, for example, a brushless DC motor can be used. It can be applied to highly accurate electrical equipment. Further, according to the method for forming a ring magnet of the present invention, a ring magnet having a desired magnetic characteristic can be created by a simple manufacturing method, which is useful for forming a ring magnet for a motor with high rotational accuracy and high output. is there.

DESCRIPTION OF SYMBOLS 10 Stator 11 Wiring board 12 Stator core 13 Coil 14 Housing 15 Bearing 20 Rotor 21 Rotating shaft 22 Rotor frame 23 Magnet 23f FG magnetized part 23m Main magnetized part 24 FG pattern 30 Molded body 30f FG compound 30m Main compound 40 Mold 41 Core 42 Dies 43 Mold cavity 44 Lower punch 45 Upper punch

Claims (14)

A ring magnet having a hollow cylindrical shape with both ends open and mounted on a motor,
A first magnet portion including a first magnetic material and subjected to a first magnetization having a different polarity in the circumferential direction;
A second magnet portion including a second magnetic material and provided with a second magnetization having a different polarity alternately in the circumferential direction more than the first magnetization,
The first magnet part and the second magnet part are arranged so that a layer of the first magnet part and a layer of the second magnet part are formed from one end to the other end direction. A ring magnet characterized by having The ring magnet according to claim 1, wherein the first magnet portion and the second magnet portion are continuously formed from one end to the other end direction. 2. The ring magnet according to claim 1, wherein each of the first magnet portion and the second magnet portion is a bonded magnet in which the magnetic materials are combined with a resin as a binder. The ring magnet according to claim 3, wherein the first magnet part and the second magnet part are coupled with each other by the resin. The first magnet portion includes the first magnetic material bonded with the resin, and the second magnet portion includes the second magnetic material bonded with the resin. The ring magnet according to claim 3, wherein the magnet part and the second magnet part are integrally formed with the resin to form a hollow cylindrical shape. The first magnetic material is an isotropic magnet powder;
2. The ring magnet according to claim 1, wherein the second magnetic material is an isotropic magnet powder having magnetic characteristics different from those of the first magnetic material. The second magnetic material has at least one of a magnetic characteristic having a small coercive force and a magnetic characteristic having a high saturation magnetic flux density as compared with the first magnetic material. 6. The ring magnet according to 6. The first magnetic material is anisotropic magnet powder;
The ring magnet according to claim 1, wherein the second magnetic material is an isotropic magnet powder. The first magnetic material is an isotropic magnet powder;
The ring magnet according to claim 1, wherein the second magnetic material is anisotropic magnet powder. The first magnetic material is anisotropic magnet powder;
The ring magnet according to claim 1, wherein the second magnetic material is anisotropic magnet powder. A motor comprising a rotor including the ring magnet according to any one of claims 1 to 10. An electric apparatus comprising the motor according to claim 11. A method of forming a ring magnet according to claim 1,
A first step of filling a mold with granules produced by kneading a magnetic powder and a resin as the second magnetic material;
A second step of filling the mold with granules produced by kneading the magnetic powder, which is the first magnetic material, and the resin;
And a third step of compressing the filler filled in the mold to form a molded body. A method of forming a ring magnet according to claim 1,
A first step of filling a mold with granules produced by kneading magnet powder and resin, which is the first magnetic material,
A second step of filling the mold with granules produced by kneading the magnetic powder, which is the second magnetic material, and the resin;
And a third step of compressing the filler filled in the mold to form a molded body.

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