JP2010021463A - Magnetizing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To magnetize different numbers of poles with a single magnetizing device without problems. <P>SOLUTION: Four magnetizing coils 3a-3d and iron cores 5 are so arranged as to sandwich a sensor magnet 6, which is for detecting the rotation of a rotor 7 supported while standing at the center of the magnetizing device, in the diameter direction of the magnet. Each core is driven by an actuator so that it is freely inserted into/pulled out from the magnetizing coil. When magnetizing four poles, all the magnetizing coils and iron cores are used for magnetization. Meanwhile, when magnetizing two poles, the iron cores corresponding to unnecessary poles are so pulled out from the magnetizing coils as to be far from a to-be-magnetized sensor magnet, so that the magnetizing magnetic field is not affected by unnecessary iron cores, and the generation of a small magnetic pole is prevented. Thereby, concerning four poles, magnetization is performed as it is, and two poles, two-pole magnetization equivalent to a two-pole magnetizing device is be performed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a magnetizing apparatus applicable to magnetizing a sensor magnet provided in a rotor of a motor.

2. Description of the Related Art Conventionally, a magnetizing device for magnetizing a sensor magnet provided on a rotor of a motor has been used to detect the rotational position of the motor (see, for example, Patent Document 1). In addition, the sensor magnet may be magnetized to 2 poles, 4 poles, or more multipoles. To cope with the difference in the number of poles, for example, a dedicated magnetizing yoke is prepared for each pole number. Depending on the number of poles, it can be changed, or a magnetizing station can be set up for each pole to make it a separate process.
JP-A-63-36507

  However, replacing the dedicated magnetizing yoke as described above and magnetizing in a separate process by dividing the magnetizing station have problems such as complicated work and wasted equipment. Therefore, for example, in order to perform magnetization of two poles and four poles by one magnetizing apparatus, a two-pole magnetizing apparatus using a four-pole magnetizing apparatus provided with a four-pole magnetizing coil is used. Sometimes it is considered that the other two poles that are unnecessary are not energized.

  In this 4-pole magnetizing apparatus, there is no problem when 4-pole magnetization is performed, but when 2-pole magnetization is performed, the 2-pole whose magnetization magnetic field is not used for other magnetizations. It has been found by the inventors' CAE analysis that a small magnetic pole having a weak magnetization is generated in the middle part of two magnetized poles under the influence of the magnetizing yoke. When magnetized in a state where such a small magnetic pole is generated, the detection accuracy of the sensor may be affected.

  In order to solve such a problem and to perform magnetization of different numbers of poles without any problem in one magnetizing device, in the present invention, the rotation integrally provided in the rotor of the motor A magnetizing device for magnetizing a sensor magnet for position detection, wherein a plurality of magnetizing coils arranged so that a plurality of sensor magnets held at a predetermined position of the rotor can be magnetized, and A plurality of iron cores coaxially disposed on each of the plurality of magnetizing coils, coil energization control means for controlling the magnetizing current to individually flow through the magnetizing coils, and the number of poles less than the plurality of poles And an iron core insertion / extraction means for inserting / removing an iron core corresponding to a pole that is not required when magnetizing the magnet in the axial direction with respect to the magnetized coil.

  In particular, the sensor magnet has a cylindrical surface on which a magnetic pole is formed, and the iron core is coaxially accommodated in the cylindrical body disposed in a direction orthogonal to the cylindrical surface. A cylindrical magnetic body, and at least a part of an axially open end of the cylindrical body is in contact with the cylindrical surface, and an axial end facing the cylindrical surface of the cylindrical magnetic body is the cylindrical surface It is good to be located in contact with or at a predetermined distance from.

  As described above, according to the first aspect of the present invention, a plurality of iron cores are coaxially disposed in each of the plurality of magnetized coils, and an iron core that is not required depending on the mode of magnetization is attached to the magnetized coil. For example, in the case of a four-pole magnetizing apparatus, four sets of magnetized coils and iron cores are arranged as four-pole magnetized parts and are not required when magnetizing two-poles. Insert and retract the iron core for 2 poles, magnetize using all magnetized coils and iron cores when magnetizing 4 poles, and remove the iron cores corresponding to unnecessary poles when magnetizing 2 poles As a result, the unnecessary iron core is far away from the sensor magnet to be magnetized, so that the magnetized magnetic field is not affected by the unnecessary iron core, and the generation of small magnetic poles can be prevented. Thereby, in the case of 4 poles, it can magnetize as it is, and also in the case of 2 poles, the 2 pole magnetization equivalent to a 2 pole magnetizing apparatus can be performed.

  According to the second aspect of the present invention, when the iron core is brought into contact with the cylindrical surface of the sensor magnet and magnetized, the rod-shaped magnetic body comes into contact with the cylindrical body containing the rod-shaped magnetic body in contact with the cylindrical surface. Since it is located at a predetermined distance, the bar-shaped magnetic body can be positioned with reference to the contact position of the cylindrical body with the cylindrical surface, and the bar-shaped magnetic body can be easily positioned.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a plan view of a magnetizing apparatus to which the present invention is applied. The magnetizing apparatus 1 shown in the figure is mainly composed of an annular support 2 and an axial line disposed on the inner peripheral side of the support 2 at intervals of 90 degrees in the circumferential direction and directed toward the center of the support 2. Four magnetizing coils 3a, 3b, 3c, 3d wound around the four, and four actuators 4a as iron core insertion / extraction means disposed on the outer peripheral surface of the support 2 in correspondence with the magnetizing coils 3a to 3d. 4b, 4c, and 4d, and an iron core 5 that is coaxially inserted into each of the magnetized coils 3a to 3d and is movable in the axial direction by the actuators 4a to 4d. A controller ECU that is electrically connected to the magnetizing coils 3a to 3d and the actuators 4a to 4d and can be individually controlled is disposed outside the magnetizing device 1.

  As shown in FIG. 2, a rotor 7 having a cylindrical sensor magnet 6 made of a magnetic material to be magnetized is erected in the axial direction of the support 2 at the center of the magnetizing device 1. A supporting chuck 8 is provided. The rotor 7 is a rotating part of the motor, and an armature, a commutator, and a sensor magnet 6 are integrally assembled on a rotating shaft. The sensor magnet 6 is positioned so as to be sandwiched between the magnetized coils 3a and 3c (3b and 3d) in a state where one end in the axial direction of the rotating shaft integral with the rotor 7 is supported by the chuck 8. In this embodiment, the sensor magnet 6 is magnetized with two or four poles on the cylindrical surface, so that the N and S poles are arranged symmetrically in the case of two poles, and N in the case of four poles. The S poles are arranged at intervals of 90 degrees so that the rotation of the rotor 7 can be detected by the case-side magnetic sensor. In the present embodiment, the sensor magnet 6 is also referred to before the magnetization.

  The magnetizing coils 3a to 3d and the iron cores 5 may have the same structure, and the magnetizing coil 3a and the iron core 5 in the present embodiment will be described with reference to FIG. As shown in FIG. 2, a base end portion (one end portion in the axial direction) of a cylindrical bobbin 9 protruding inward in the radial direction is fixed on the inner peripheral surface of the support body 2. A magnetizing coil 3a is wound around the surface of the protruding end (the other end in the axial direction) side. The bobbin 9 may be made of, for example, stainless steel in order to ensure rigidity sufficient to withstand winding of a thick coil wire, and a non-magnetic material. The magnetized coil 3a wound around the bobbin 9 is covered and fixed with an epoxy resin.

  A through hole 2a (see FIG. 1) having the same diameter as the axial hole 9a of the bobbin 9 is formed in the support 2 coaxially. The iron core 5 is inserted through the axial hole 9a. The iron core 5 is made of, for example, a stainless steel material and includes a cylindrical pipe 5a and a laminated steel plate 5b serving as a rod-shaped magnetic body housed in the pipe 5a. The outer diameter of the pipe 5a and the inner diameters of the holes 9a and 2a are preferably substantially the same so that the pipe 5a can be displaced in the axial direction and the misalignment is minimized. The pipe 5a is also inserted into the through hole 2a and extends to the outside of the support 2 as shown in FIG. The laminated steel plate 5b is formed in a cylindrical shape having an outer diameter substantially the same as the inner diameter of the pipe 5a by laminating magnetic thin plates in the radial direction of the pipe 5a. The length may be a little longer than the length of the winding range of the coil 3a.

  As shown in FIG. 1, the pipe 5 a is integrated with the drive rods of the actuators 4 a to 4 d outside the support body 2. In the illustrated example, the drive rods of the actuators 4a to 4d and the pipe 5a are shown to have the same diameter and are connected to each other by being coaxially abutted. However, both members may be coupled by flange coupling. . In the embodiment, a direct acting actuator 4 is used, and the pipe 5a, that is, the iron core 5 is displaced in the insertion / extraction direction (arrow B in FIG. 1) with respect to the bobbin 9 by reciprocating the drive rod of the actuator. Can do.

  In the present embodiment, as shown in FIG. 3A showing the position of the iron core 5 when magnetized with respect to the sensor magnet 6, the tip of the pipe 5a abuts against both ends in the axial direction of the sensor magnet 6 during magnetization. At the same time, the end surface 5c of the laminated steel plate 5b comes into contact with the outer peripheral surface formed of the cylindrical surface of the sensor magnet 6. In the example shown in FIG. 3A, the axial distance d between the tip of the pipe 5a and the end surface of the laminated steel plate 5b is set so as to satisfy both the above-described contact states. Note that the end surface of the laminated steel plate 5b does not need to contact the sensor magnet 6, and in this case, the interval is appropriately set to a predetermined length (> d).

  In the present invention, a single magnetizing device enables magnetizing with different numbers of poles. In the case of the magnetizing device 1 of the illustrated example, four-pole magnetizing and two-pole magnetizing are possible. In the case of quadrupole magnetization, all the actuators 4 are driven and all the iron cores 5 of the four poles are brought into contact with the sensor magnet 6 as shown in FIG. Shed. In the case of quadrupole magnetization, a current is passed so that the opposing magnetized coils 3 have the same magnetic pole.

  On the other hand, in the case of two-pole magnetization, for example, the upper and lower two iron cores 5 in FIG. 1 are positioned in the same manner as the four-pole magnetization for magnetization, and the other two poles (left and right in FIG. The two iron cores 5 are driven in the direction away from the sensor magnet 6 by the actuators 4a and 4c. In FIG. 3B, the separation distance is a position where the tip of the iron core 5 comes out of the range where the magnetizing coils 3a and 3c are wound, but the current flows to the magnetizing coils 3b and 3d for magnetizing. Any position may be used as long as no distortion of magnetic flux occurs in the magnetizing magnetic field generated by the flow of. When dipole magnetization is performed, a current is passed so that the opposite magnetizing coils 3b and 3d for magnetization have different polarities (one is an N pole and the other is an S pole).

  FIG. 4 (a) shows the state of the magnetizing magnetic field when dipole magnetization is performed by separating the iron core 5 corresponding to unnecessary magnetic poles as described above. In this case, a magnetizing magnetic field in which the magnetic flux becomes almost parallel is generated between the iron cores 5 facing each other in the vertical direction in the figure, as indicated by the three arrows in the figure, and the sensor magnet 6 is magnetized in two poles. The The magnetized state has a clean waveform as shown in FIG. In FIG. 5, the vertical axis represents the magnetic flux density (displayed with the NS pole corresponding to + −), and the horizontal axis represents the rotation angle of the sensor magnet 6.

  On the other hand, when the conventional four-pole magnetizing apparatus is used as it is and the two-pole magnetization is performed, the iron core not used for the magnetization is also in the magnetized position as shown in FIG. When dipole magnetization is performed in the same manner as described above, the magnetic flux is pulled to the iron core that is not used for magnetization as shown by the three arrows in FIG. The sensor magnet 6 is magnetized with the magnetization direction swelled in an arc shape radially outward. The magnetized state has a waveform as shown in FIG.

  In this way, when two-pole magnetization is performed using the four-pole magnetizing apparatus as it is, the rotation angles orthogonal to the magnetized rotation angles (90 degrees and 270 degrees) are around 180 degrees and 360 degrees. The small magnetic pole Ts appears under the influence of the change in the magnetization direction of the magnetizing magnetic field (FIG. 5B). When magnetized in a state where the small magnetic pole Ts is generated, the detection accuracy of the sensor is adversely affected. On the other hand, by separating the unnecessary iron core 5 from the sensor magnet 6 as in the present invention, distortion of magnetic flux in the magnetizing magnetic field does not occur, and a dedicated two pole as shown in FIG. Magnetization that is the same as when magnetized by a magnetizing device can be performed.

  As a result, as shown in the above embodiment, since one magnetizing device 1 can mix four or two poles, two conventional magnetizing devices have been provided. Compared to the case, the installation space for one vehicle may be sufficient, and the space efficiency of the equipment can be improved. Further, since at least the two-pole magnetizing coil and the auxiliary device associated therewith can be omitted, the production cost of the device can be reduced.

  In the present embodiment, four-pole or two-pole magnetization has been shown using a four-pole magnetizing apparatus. However, according to the present invention, the present invention is not limited to this. The present invention can be applied as a magnetizing device that magnetizes a part of the magnet.

  In the above embodiment, all the iron cores 5 are provided so as to be freely inserted into and extracted from the magnetizing coils 3a to 3d. However, the iron core that is always required (for two-pole magnetization) may be in a fixed state. In the case of application to the above-described embodiment, it is possible to cut off a portion which is the tip portion of the pipe 5 a and interferes with the sensor magnet 6 when the rotor 7 is set. In addition, although the actuators 4a to 4d are respectively provided and automated, the rear end portion of the bobbin 9 may be manually pushed and pulled, thereby reducing the production cost when using the magnetizing device alone.

  The magnetizing apparatus according to the present invention can be performed by a single magnetizing apparatus even when magnetizing a sensor magnet provided on a rotor of a motor with a different number of poles for each motor. It is also useful as a magnetizing device that performs multi-pole magnetization.

It is a top view of the magnetizing apparatus to which this invention was applied. It is the figure seen along the arrow II-II line of FIG. (A) is a principal part expanded cross section which shows the iron core of a magnetization state, (b) is a figure corresponding to (a) which shows the iron core of a non-magnetization state. (A) is explanatory drawing which shows the magnetization magnetic field at the time of 2 pole magnetization by the 4 pole magnetizing apparatus based on this invention, (b) is a figure corresponding to the conventional (a). (A) is a wave form diagram which shows the magnetization result by the 2 pole magnetization by the 4 pole magnetizing apparatus based on this invention, (b) is a figure corresponding to the conventional (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Magnetization apparatus 3a * 3b * 3c * 3d Magnetization coil 4a * 4b * 4c * 4d Actuator 5 Iron core, 5a Pipe, 5b Laminated steel plate, 5c End surface 6 Sensor magnet 7 Rotor

Claims (2)

A magnetizing device for magnetizing a sensor magnet for detecting a rotational position provided integrally with a rotor of a motor,
A plurality of magnetizing coils arranged to be capable of magnetizing a plurality of the sensor magnets held at predetermined positions of the rotor; and a plurality of iron cores arranged coaxially to each of the plurality of magnetizing coils; Coil energization control means for controlling the respective magnetizing currents individually to flow through the magnetizing coil, and magnetizing an iron core corresponding to a pole that is unnecessary when magnetizing less than the plurality of poles A magnetizing apparatus comprising iron core insertion / extraction means for inserting / extracting the coil in the axial direction. The sensor magnet has a cylindrical surface on which a magnetic pole is formed,
The iron core has a cylindrical body disposed in a direction orthogonal to the cylindrical surface, and a rod-shaped magnetic body accommodated coaxially in the cylindrical body,
In a state where at least a part of the axially open end of the cylindrical body is in contact with the cylindrical surface, the axial end of the rod-shaped magnetic body facing the cylindrical surface is in contact with the cylindrical surface or predetermined The magnetizing device according to claim 1, wherein the magnetizing device is located at a distance.

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