JP4478905B2 - Linear motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a linear motor used as constant speed feed or precision positioning feed in the fields of semiconductor manufacturing equipment and machine tools, for example.
[0002]
[Prior art]
Conventionally, a linear motor used as a precision positioning feed for a table of a semiconductor exposure apparatus or a machine tool is as shown in FIG. 5A and 5B show a conventional linear motor, in which FIG. 5A is a partial sectional side view showing the configuration, and FIG. 5B is an enlarged view of the field part of FIG.
In the figure, 21 is an armature of a linear motor, 22 is an armature mounting plate, 23 is an armature core, 24 is an armature coil, 25 is a field yoke, and 26 is a permanent magnet. In addition, illustration is abbreviate | omitted about the linear guide for supporting the needle | mover of a linear motor.
The armature 21 includes an armature core 23 in which electromagnetic steel plates are punched in a comb shape and stacked and fixed, and an armature coil 24 housed in a winding housing groove of the armature core 23. It is attached to the back side. Further, as shown in FIG. 5B, the permanent magnets 26 are arranged at equal intervals on the flat field yoke 25 constituting the field so that the polarities of adjacent magnets are alternately different, For example, an Nd—Fe—B based sintered magnet (maximum energy product = about 45 MGOe) is used.
In such a configuration, when the armature coil 24 of the linear motor is energized, a magnetic flux flows as indicated by the dotted line in the figure. The armature 21 moves in the linear direction by the electromagnetic action of the armature coil 24 and the permanent magnet 26.
Next, a conventional magnetizing process of the linear motor field part will be described. FIG. 6 shows a conventional field permanent magnet magnetizing apparatus.
In the figure, 27 is a magnetizing device, 28 is a magnetizing yoke, 29 is an electromagnet coil, 30 is a switch, 31 is a capacitor, 32 is a rectifier, and 33 is a power source.
First, the same number of unmagnetized permanent magnets 26 as the number of poles of the linear motor are bonded and fixed on the field yoke 25 at a predetermined interval. Next, a magnetization formed by a magnetizing yoke 28 and an electromagnet coil 29, which is formed in advance according to the size and arrangement of the unmagnetized permanent magnet 26 and whose width corresponds to the arrangement length of two permanent magnets. The device 27 is disposed along the longitudinal direction of the field yoke 25 so as to face the non-magnetized permanent magnet 26. Subsequently, one permanent magnet 26 is supplied with electric current from the power source 33 to the electromagnet coil 29 so that the direction of magnetization from the attachment surface 26A with the field yoke 25 toward the magnetizing yoke 28 is changed from S pole to N pole. In addition, the magnetization direction of the other adjacent permanent magnet 26 is changed from the S pole to the N pole from the magnetizing yoke 28 side toward the mounting surface 26A of the permanent magnet 26 with the field yoke 25. A current is supplied to the electromagnet coil 29. Thus, the magnetic field leaking from the magnetizing yoke 28 is magnetized by alternately changing the polarities of the adjacent permanent magnets 26. The capacitor 31 and the rectifier 32 are used to stabilize the current of the power supply 33.
[0003]
[Problems to be solved by the invention]
However, the conventional linear motor has the following problems.
(1) The number of field parts of the linear motor is the same as the number of poles of the motor. Since a permanent magnet made of an expensive rare earth magnet is used, the parts cost of the entire linear motor is increased.
(2) In the process of fixing the permanent magnet to the field yoke by bonding or the like, the number of permanent magnets equal to the number of poles of the motor must be fixed on the field yoke at equal intervals. At the same time as the work is troublesome, especially when the number of poles of the motor increases, the number of assembly steps of the permanent magnet increases and the assembly cost increases.
(3) For magnetizing work, a dedicated magnetizing yoke that matches the arrangement of the longitudinal width and magnet pitch of the permanent magnet is required, and for this reason, the permanent magnet and magnetizing yoke must be positioned precisely. It must be troublesome.
(4) Also, in the magnetizing operation, if the distance between the permanent magnet and the magnetizing yoke and the positioning in the longitudinal direction are insufficient, the permanent magnet cannot be magnetized uniformly. The magnetic field generated in the field part was varied, which adversely affected the motor performance.
The present invention has been made to solve the above-described problems, and an object thereof is to provide an inexpensive linear motor that is easy to magnetize and assemble permanent magnets without deteriorating motor performance. And
[0004]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the present invention of claim 1 is arranged such that a field portion of a linear motor in which a plurality of field permanent magnets are arranged side by side on a field yoke, and opposed to the field portion, An armature portion of a linear motor in which an armature coil is wound through a permanent magnet row and a magnetic gap so as to extend along the longitudinal direction of the field yoke. Plural protrusions are provided at equal intervals in the direction, and the permanent magnet is arranged between adjacent protrusions of the field yoke with the polarities aligned in the same direction toward the surface facing the magnetic gap. The linear yoke is configured to run relatively with one of the field part and the armature part as a stator and the other as a mover. The field yoke is configured in two rows. And sandwiching the armature between the two rows of field yokes Are arranged, it is characterized in that are aligned position of one of the permanent magnets arranged in a position and the other of the field yoke of projections arranged in field yoke.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a linear motor showing a first embodiment of the present invention, in which (a) is a partial sectional side view of the structure, and (b) is an enlarged view of the field part.
1 is an armature, 2 is an armature mounting plate, 3 is an armature core, 4 is an armature coil, 5 is a field yoke, 5A is a protrusion, and 6 is a permanent magnet. The present embodiment is an example of a gap-facing structure in which the field yoke faces the armature through a magnetic gap, and the moving coil has the armature as a mover and the field yoke as a stator. The basic configuration of the linear motor is the same as the conventional one. The illustration of the linear guide serving as a support mechanism for the mover is omitted as in the prior art.
The points where the present invention is different from the prior art will be described below.
The field yoke 5 is provided with a plurality of protrusions 5A at equal intervals in the longitudinal direction, and the permanent magnet 6 is disposed between the adjacent protrusions 5A of the field yoke 5 on the surface facing the magnetic gap G. All the magnetization directions are magnetized from the S pole to the N pole and the polarities are aligned in the same direction. In this manner, the field portion is configured by alternately arranging the protrusions and the permanent magnets on the field yoke.
Next, the operation will be described.
If the permanent magnet 6 magnetized with the same polarity in the field part of the linear motor is arranged on the field yoke 5 so as to alternate with the protrusions 5A of the field yoke 5, for example, a permanent magnetic pole with N poles is permanent. The magnet 6 and the adjacent protrusion 5A serve as an opposite magnetic pole (S pole). In such a configuration, when the armature coil 4 is energized, the magnetic flux generated in the armature coil 4 flows along the teeth portion of the armature core 3 as indicated by the dotted line in the figure, passes through the permanent magnet 6 and the field. It flows again to the teeth portion of the armature core 3 through the adjacent protrusion 5A from the magnetic yoke 5. Due to the electromagnetic action of the armature coil 4 and the permanent magnet 6, a magnetic field corresponding to the number of poles necessary for the linear motor is generated, and the armature 1 moves in the linear direction.
Next, the operation of the linear motor having the field configuration shown in the present embodiment was confirmed. As a result, when the linear motor of this example used a permanent magnet of the same size as the prior art, the thrust characteristic was lower than that of the conventional one. On the other hand, measures such as increasing the thickness of the permanent magnet were taken. By applying this, it was confirmed that a thrust characteristic equivalent to that of the prior art was obtained.
Therefore, the field portion of the linear motor is composed of a field yoke having protrusions formed at equal intervals, and a permanent magnet that is magnetized in the same direction between the protrusions of the field yoke and has the same polarity, Since the permanent magnets and the projections of the field yoke are arranged alternately on the field yoke, the number of permanent magnets is smaller than that of a conventional linear motor that requires the same number of permanent magnets as the number of motor poles. A linear motor that can be halved and has low component costs can be provided.
Also, since the permanent magnets are bonded between the projections of the field yoke, the positioning of the magnets is easy, making the bonding work easy, reducing the number of assembly steps required for bonding the permanent magnets, and reducing the assembly cost. An inexpensive linear motor can be provided.
Furthermore, if the number of poles of the linear motor is increased by reducing the number of permanent magnets arranged in the field yoke or if a longer stroke of the mover is required, the moving coil type linear motor can be used. , Parts cost and assembly cost can be greatly reduced.
[0006]
Next, a second embodiment of the present invention will be described.
FIG. 2 is a side sectional view of a linear motor showing a second embodiment of the present invention. In this embodiment, an example of a coreless linear motor having a coreless armature is shown.
The linear motor of this embodiment is different from that of the gap facing structure shown in the first embodiment in that the field yoke is composed of two rows (9, 91 in the figure) and two rows. Of the so-called magnetic flux penetration type structure in which the armature 7 is sandwiched between the field yokes 9 and 91, and the position of the projection 9A disposed on one field yoke 9 and the other field yoke This is that the positions of the protrusions 91 </ b> A arranged at 91 are aligned. Since the operation is substantially the same as that of the first embodiment, the description thereof is omitted.
In the second embodiment, the linear motor characteristics equivalent to those of the first embodiment can be obtained by adopting such a configuration, and permanent magnets can be magnetized and assembled to provide an inexpensive linear motor. Can be provided.
[0007]
Next, a third embodiment of the present invention will be described.
FIG. 3 is a sectional side view of a linear motor showing a third embodiment of the present invention. In addition, the present Example has shown the example of the coreless linear motor similarly to 2nd Example.
This embodiment is different from the second embodiment in that in the configuration of the field yokes 9 and 91 formed of two rows, the position of the protrusion 9A disposed in one field yoke 9 and the other field yoke 91 are disposed. The positions of the permanent magnets 6 are aligned. Since the operation is substantially the same as the first and second embodiments, the description thereof is omitted.
In the third embodiment, the linear motor characteristics equivalent to those of the first and second embodiments can be obtained by such a configuration, and permanent magnets can be magnetized and assembled. A motor can be provided.
[0008]
Next, a fourth embodiment of the present invention will be described.
FIG. 4 is a configuration diagram of a field permanent magnet magnetizing device when applied to a linear motor according to a fourth embodiment of the present invention.
In the figure, 11 is a magnetizing device, 12 is a magnetizing yoke, 13 is an electromagnet coil, 14 is a switch, 15 is a capacitor, 16 is a rectifier, and 17 is a power source.
The field yoke 5 has projections 5A arranged at equal intervals in the longitudinal direction, and permanent magnets 6 are arranged between the projections 5A. Further, the magnetizing device 11 is disposed along the longitudinal direction of the field yoke 5 so that the upper and lower sides of the permanent magnet 5 are sandwiched by two sets of the electromagnet coil 13 and the magnetized yoke 12 respectively.
In such a configuration, first, an unmagnetized permanent magnet 6 is bonded and fixed between the projections 5A of the field yoke 5. Next, along the longitudinal direction of the field yoke 5, the upper and lower sides of the permanent magnet 5 disposed on the field yoke 5 are sandwiched between the electromagnet coil 13 and the magnetized yoke 12. Subsequently, the magnetization direction of one permanent magnet 6 is changed from the S pole to the N pole from the mounting surface 6A to the field yoke 5 to the side opposite to the mounting surface 6A to the field yoke 5. Current is supplied by an electromagnetic coil in one direction. In this way, the permanent magnets 6 are magnetized by the magnetic field leaking from the magnetized yoke 12, so that the polarities of the adjacent permanent magnets 6 are the same.
Therefore, in the magnetizing method of the field permanent magnet according to the present embodiment, the direction of the current supplied to the electromagnet coil is changed in order to magnetize the adjacent permanent magnets so that the polarities are alternately different as in the prior art. The permanent magnets can be easily and uniformly magnetized because all permanent magnets have only to be magnetized to the same polarity. In addition, since there is no need for a dedicated magnetizing device that matches the size and arrangement of the permanent magnets, there is no need to precisely position the permanent magnet and the magnetizing yoke, and the permanent magnet is located between the upper and lower magnetizing yokes. Therefore, there is no significant change in the magnetization magnetic field strength, and the magnetic field generated by the linear motor field part does not vary. As a result, the motor performance is not adversely affected.
In this embodiment, the linear motor field part is used on the stator side. However, the linear motor field part may be used as a mover and is not limited to the type or structure of the linear motor.
In addition, the permanent magnet used in this example may be replaced with an Nd—Fe—B based sintered magnet, and may be an Sm—Co based sintered magnet or a ferrite magnet, and is limited to the type of material. is not.
In the present embodiment, an example has been shown in which two permanent magnets can be magnetized simultaneously and with the same polarity by one magnetizing yoke. However, the permanent magnets can be magnetized one by one. It may be changed to a magnetized yoke having a structure matching one width, or the longitudinal width of the magnetized yoke along the permanent magnet row direction is increased so that a plurality of permanent magnets can be magnetized simultaneously. It may be changed as appropriate.
The magnetizing device is composed of an electromagnet coil and a magnetizing yoke. However, when the generated magnetizing magnetic field is restricted by the saturation magnetization of the magnetizing yoke, such a magnetizing device is used. Alternatively, an air-core coil without the magnetizing yoke may be used. This case is effective when it is necessary to magnetize with a strong magnetic field.
[0009]
【The invention's effect】
As described above, according to the present invention, the magnetic field of the linear motor is magnetized in the same direction between the field yoke having protrusions formed at equal intervals and the protrusions of the field yoke. Linear magnets that required the same number of permanent magnets as the number of motor poles in the past by arranging the permanent magnets and the projections of the field yoke alternately. Compared to motors, the number of permanent magnets can be halved, the number of assembly steps required to attach permanent magnets can be reduced, and the assembly can be facilitated, providing a linear motor field section with low parts and assembly costs. can do.
Also, in the method of magnetizing field permanent magnets according to the present embodiment, all the adjacent permanent magnets have the same polarity as in the prior art in which the polarities of adjacent permanent magnets are alternately different. Thus, the permanent magnet can be easily magnetized uniformly. In addition, since a dedicated magnetizing device that matches the size and arrangement of the permanent magnets can be eliminated, there is no need to precisely position the permanent magnet and the magnetizing yoke. Can be provided.
[Brief description of the drawings]
FIG. 1 is a linear motor showing a first embodiment of the present invention, in which (a) is a side sectional view of the overall configuration, and (b) is an enlarged view of a field part of (a).
FIG. 2 is a side sectional view of a linear motor showing a second embodiment of the present invention.
FIG. 3 is a side sectional view of a linear motor showing a third embodiment of the present invention.
FIG. 4 is a configuration diagram of a field permanent magnet magnetizing apparatus when applied to a linear motor according to a fourth embodiment of the present invention.
5A is a side sectional view of the entire configuration of a conventional linear motor, and FIG. 5B is an enlarged view of a field portion of FIG. 5A.
FIG. 6 shows a conventional field permanent magnet magnetizing apparatus.
[Explanation of symbols]
1: Armature 2: Armature mounting plate 3: Armature core 4: Armature coil 5: Field yoke 5A: Projection 6: Permanent magnet 6A: Mounting surface of permanent magnet with field yoke 7: Armature 8: Armature coils 9, 91: Field yoke 9A, 91A: Protrusion 10: Permanent magnet 11: Magnetizing device 12: Magnetizing yoke 13: Electromagnetic coil 14: Switch 15: Capacitor 16: Rectifier 17: Power supply G: Magnetic gap

Claims (1)

A field portion of a linear motor in which a plurality of field permanent magnets are arranged on the field yoke;
  An armature portion of a linear motor that is disposed opposite to the field magnet portion and wound with an armature coil through the permanent magnet row and a magnetic gap along the longitudinal direction of the field yoke;
With
  The field yoke is provided with a plurality of protrusions at equal intervals in the longitudinal direction thereof,
  The permanent magnet is arranged between adjacent projections of the field yoke with the polarities aligned in the same direction toward the surface facing the magnetic gap,
  In a linear motor that travels relatively using either the field part or the armature part as a stator and the other as a mover,
  The field yoke is composed of two rows and is disposed with the armature sandwiched between the two rows of field yokes. The position of the protrusion disposed on one field yoke and the other field yoke Linear motors characterized in that the positions of the permanent magnets arranged in

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