JPH1052025A - Linear motor and its control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a motion characteristic of a linear motor and its safety when using it in a vertical axis, by reducing the irregularity of its thrust. SOLUTION: In a linear motor having a fastened magnet plate 15 with magnet pieces (permanent magnets 13, 14) provided extensively on both sides thereof and having a pair of armatures 11, 12 which face on each other with the magnet plate 15 between them and move integrally with each other, various phases are shifted to such directions that the irregularities of two thrusts generated on both sides of the magnet plate 15 are canceled therein to reduce thereby the irregularity of the thrust of the linear motor. That is, using a configuration for so arranging the magnetic poles of the magnet pieces 13, 14 that their phases are shifted to each other on both sides of the magnet plate 15, and using a configuration for shifting to each other the phase sequences of the windings of the pair of armatures 11, 12, and further, using current controls for adjusting the phases of the currents fed to the pair of armatures 11, 12, the phases of the irregularities of the two thrusts generated on both sides of the magnet plate 15 are shifted to each other to make the irregularity of the thrust of the linear motor reducible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet synchronous type linear motor widely used for driving a movable member of a machine tool and the like, and more particularly to an arrangement of a permanent magnet and a movable magnet and a permanent magnet. The present invention relates to control for supplying a drive current to a magnet.

[0002]

2. Description of the Related Art Permanent magnet synchronous linear motors are widely used for driving movable members of machine tools. In this permanent magnet linear motor, a moving magnetic field generating means and a fixed magnetic field including a plurality of permanent magnets whose magnetic poles are alternately arranged in NS order are movably opposed to and close to each other. FIG. 13 is a schematic perspective view of a linear motor. In a linear motor, the magnetic pole of the fixed magnetic field is
The magnets are sequentially arranged and mounted on a magnetic plate such as an iron plate corresponding to the size of the magnetic poles of the permanent magnet such that the magnetic poles are alternated in NS order. In the figure, the magnet plate 20 is a yoke and has a size corresponding to the size of the magnetic pole.
It has a width of about mm and a length of 500 mm to 10 m, and is formed of a soft iron plate. The magnet piece 22 is a permanent magnet having a magnetic flux density of about 1 Tesla and a thickness of about 5 mm. As shown, the upper surface is magnetized with N and S poles, and the lower surface is with S and N poles of opposite polarity. The magnet piece 22
Can be attached to the magnet plate 20 by embedding with a resin layer.

The armature 22 is movably attached to the fixed magnetic field, and relative movement between the armature and the fixed magnet is performed by the interaction between the magnetic field on the fixed magnet side and the magnetic field on the armature side. be able to. In addition, the moving member is attached to the armature side or the fixed magnet side, thereby,
The moving member can be moved.

In driving the above-described permanent magnet synchronous linear motor, when one linear motor is driven, it is usually performed by current control as shown in FIG. In the current control shown in FIG. 14, a current command is converted into a U-phase, V-phase, and W-phase three-phase command in a three-phase command conversion block 1, and each command is converted into a U-phase current command block 2u and a V-phase current, respectively. Command block 2v and W-phase current command block 2w
To generate a current command for each phase. The current command of each phase is amplified by the amplifiers 3u, 3v, and 3w of each phase and supplied to the coils of each phase of the linear motor 4. In addition,
Each of the amplifiers 3u, 3v, and 3w performs current feedback. Further, the linear motor 4 is provided with a magnetic pole detector 5 for detecting the position of the magnetic pole, and the magnetic pole position detected by this detector is fed back to the three-phase command conversion block 1.

On the other hand, in the case of driving a plurality of linear motors in driving a permanent magnet synchronous linear motor, conventionally, as shown in FIG. 15, the drive of one linear motor is controlled. A plurality of mechanisms are provided to independently control a common current command. FIG.
When a control system is provided independently for each linear motor as shown in (1), a magnetic pole detector for detecting the magnetic pole position of the linear motor is required individually. A and b in FIG.
A drive control system for controlling the drive of the linear motor 4a and the second linear motor 4b.
a, a first phase current command block 2a, a first amplifier 3a, a first linear motor 4a, a first magnetic pole detector 5a, and a second three-phase command converter 1b and a second phase current command block 2 having the same configuration.
b, a first amplifier 3b, a first linear motor 4b, and a first magnetic pole detector 5b.

When a plurality of linear motors are in the same driving state as the linear motor having the above configuration, the detection signals of the magnetic pole detectors are the same, and one magnetic pole detector is used in common. Can be. For example, in a linear motor having a configuration in which armatures are arranged on both sides of a common fixed magnetic pole, both armatures are integrated and have a common position with respect to the fixed magnetic pole. In such a usage form, drive control can be performed by installing only one magnetic pole detector for a plurality of linear motors. When a plurality of linear motors are driven by this one magnetic pole detector, each of the plurality of linear motors has one common three-phase command generated by a magnetic pole position signal fed back from one magnetic pole detector. Is supplied and driven.

[0007]

When the permanent magnet synchronous linear motor is driven by one common three-phase command as described above, the thrust caused by the non-uniform magnetic flux distribution of the fixed magnetic poles of the permanent magnet. Unevenness occurs, and this thrust unevenness causes a reduction in feed accuracy of a drive device using a linear motor, and has a problem that the performance of a device such as a machine tool in which the linear motor is incorporated is affected.

[0008] The linear motor is constituted by two sets of armatures opposed to each other and a fixed magnet plate which is inserted between the two sets of armatures and has two sets of magnets mounted back to back. In this case, the relationship between the magnetic pole positions of the two sets of magnets is the same, and the armature is driven by supplying an in-phase current.

FIG. 16 is a diagram for explaining the arrangement of fixed magnetic poles and armatures in a linear motor. In FIG. 16, permanent magnets 13 and 14 are arranged on both sides of a fixed magnet plate 15 such that the same magnetic poles face each other, thereby forming a fixed magnetic pole. The armatures 11 and 12 are arranged on both sides of the fixed magnetic pole so as to be close to each other so that the coil portion faces the permanent magnet of the fixed magnetic pole. For example, the armature 11 is a three-phase coil (coil 11u, coil 11v, coil 11
w), and the armature 12 has a three-phase coil (coil 1).
2u, a coil 12v, and a coil 12w), and the coils of each phase of both armatures are arranged to face each other. Hereinafter, the armature 11 side will be described as A side, and the armature 12 side will be described as B side.

[0010] Each armature of the linear motor having the above arrangement has uneven thrust as shown in FIG. When this uneven thrust is examined with reference to FIG. 18, the thrust generated by each armature is obtained by synthesizing the thrust for one phase of the armature shown in FIG.
The combined thrust shown in FIG. FIG. 18 (d) and FIG.
8 (e) shows only the thrust unevenness of the combined thrust on the A side and the B side. The phases of the thrust irregularities on the A side and the B side are:
Since both armatures are arranged in the same positional relationship with respect to the fixed magnetic pole, they coincide. Therefore, the thrust unevenness of the linear motor is obtained as a combination of the thrust unevenness on both sides as shown in FIG. Note that, in the positional relationship between the fixed magnetic poles and the armature in FIG. 18A, the coils of the armature are shown at 240 ° intervals.

In such a linear motor having uneven thrust, the armature tends to stop at a stable point during an emergency stop or the like, so that the armature may largely move toward the stable point.

Accordingly, an object of the present invention is to solve the above-described problems of the conventional linear motor and to reduce thrust unevenness in the linear motor, thereby improving the motion characteristics and safety of the linear motor. Things.

[0013]

SUMMARY OF THE INVENTION A linear motor according to the present invention includes a magnet plate having magnet pieces extending on both sides thereof, and a pair of armatures which are provided between the magnet plates and move integrally. In the linear motor, the phase is shifted in a direction to cancel out the two thrust unevenness generated on both sides of the magnet plate,
Thereby, thrust unevenness in the linear motor is reduced. Further, by arranging the magnetic poles of the magnet pieces so that the phases are shifted on both sides of the magnet plate, shifting the phase sequence of the windings of the pair of armatures, and adjusting the phase of the current supplied to the armature, The phases of the two thrust irregularities can be shifted.

The linear motor of the present invention has a magnet plate having a plurality of magnet pieces extending on both sides thereof in one axial direction, and a magnet plate which is provided opposite to both surfaces of the magnet plate via an action gap, and has a magnetic field generated by the magnet pieces. In a linear motor having a pair of armatures having windings for performing electromagnetic interaction and being integrally movable with respect to the magnet plate in the axial direction, the phases of the magnetic poles of the magnet pieces on both sides of the magnet plate are shifted from each other. With this arrangement, the phases of the two thrust unevennesses generated between the pair of armatures and the magnet plate are shifted to reduce the two thrust unevennesses (corresponding to claim 1).

The linear motor according to the present invention is the linear motor having the same configuration as described above, wherein the magnetic poles of the magnet pieces on both sides of the magnet plate are arranged out of phase with each other, and a pair of armature windings is provided. Are shifted from each other, whereby the phases of the two thrust unevennesses generated between the pair of armatures and the magnet plate are shifted to reduce the two thrust unevennesses. ).

Further, the thrust unevenness generated by the electromagnetic interaction between the magnetic pole of one magnet piece and the facing armature, and the thrust generated by the electromagnetic interaction between the magnetic pole of the other magnet piece and the facing armature. The phase of the magnetic pole is set so as to make the unevenness the opposite phase (corresponding to claim 3). Further, the phase of this magnetic pole is set to the phase of the magnetic pole of one magnet piece with respect to the magnetic pole of the other magnet piece. Is shifted by half of one magnetic pole (corresponding to claim 4).

A linear motor according to the present invention has a magnet plate in which a large number of magnet pieces extend in one axial direction on both sides thereof, and the magnetic poles on each side are arranged out of phase with each other; And a pair of armatures, each of which has a pair of windings that perform electromagnetic interaction with a magnetic field generated by a magnet piece and are integrally movable with respect to the magnet plate in the axial direction. Supply a common mode current to the pair of armatures,
The phase of the current is determined by the magnitude of the phase difference between the magnetic field generated by the current and the magnetic field generated by the magnet piece facing one of the armature windings, and the magnet piece facing the magnetic field generated by the current in the other armature winding. This controls the magnitude of the phase shift between the magnetic field and the magnetic field caused by the same, thereby shifting the phases of the two thrust unevennesses generated between the pair of armatures and the magnet plate, thereby reducing the two thrust unevennesses. It is intended to reduce (corresponding to claim 5). The same control can be performed for a linear motor having a configuration in which the phase order of the windings of the pair of armatures is shifted from each other (corresponding to claim 6).

In the linear motor of the present invention, in a linear motor having the same configuration as the linear motor performing the above method, a different-phase current is supplied to a pair of armatures, and a phase of the current supplied to each armature is adjusted. The magnetic field generated in the armature winding by the current and the magnetic field generated by the facing magnet piece are controlled so that the phases of the magnetic fields coincide with each other, whereby both thrusts generated between the pair of armature and the magnet plate are controlled. The phase of the unevenness is shifted to reduce unevenness of both thrusts (corresponding to claim 7). Similar control can also be performed for a linear motor having a configuration in which the phase order of the windings of a pair of armatures is shifted from each other (corresponding to claim 8).

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 and 2 are block diagrams for explaining a control system for driving the linear motor of the present invention. The linear motor of the present invention uses one magnetic pole position signal obtained from one magnetic pole detector,
It is premised on a control mode in which a plurality of permanent magnet synchronous linear motors are driven by one common three-phase command. The control system diagrams shown in FIGS. 1 and 2 are an example of the above-described control mode.

In the current control shown in FIG. 1, a current command is converted into a U-phase, V-phase, and W-phase three-phase command in a three-phase command conversion block 1, and each command is converted into a U-phase current command and a V-phase current command, respectively. Command and a W-phase current command are sent to a block 2 (three-phase blocks are collectively shown as one block in the figure) to generate a current command for each phase. The current command of each phase is indicated by the amplifier 3 of each phase (in FIG.
The current is amplified by a single block, and supplied to the coils of each phase of a plurality of linear motors (first linear motor 4a, second linear motor 4b). Each amplifier 3 performs current feedback. The position of the magnetic pole is detected by a magnetic pole detector 5 provided in one of the plurality of linear motors 4a and 4b, and the detected magnetic pole position is fed back to the three-phase command conversion block 1. In FIG. 1, as a plurality of linear motors,
As an example, a first linear motor 4a and a second linear motor 4
Although two devices b are shown, any number of two or more devices may be used.

In the control system having the above-described configuration, since a single amplifier 3 supplies a drive current to a plurality of linear motors, a large-capacity amplifier is required.

In the current control shown in FIG.
A plurality of systems (systems a and b surrounded by broken lines in FIG. 2) having the configuration of the three-phase command conversion block 1, the phase current command block 2, the amplifier 3, and the linear motor 4 shown in FIG. One magnetic pole position signal obtained from the magnetic pole detector 5 provided in the inner linear motor is used in common for a plurality of systems.

FIG. 3 shows a first example of the linear motor of the present invention when the linear motor is driven by the control system described above.
FIG. The first mode is a control example in the case where an in-phase current is supplied to an armature. FIG.
3 schematically shows the arrangement of fixed magnetic poles and armatures in a linear motor. In FIG. 3, the magnetic poles of the magnet pieces composed of the permanent magnets 13 and 14 are arranged on both sides of the fixed magnet plate 15 with their phases shifted, thereby forming a fixed magnetic pole. This phase shift of the magnetic poles, for example, causes the magnetic poles of one magnet piece to be out of phase with the magnetic poles of the other magnet piece by half of one magnetic pole. Thus, if the change in the magnetic field due to a set of N and S poles is 360 °, the magnetic poles will be 90 ° out of phase with each other. The armatures 11 and 12 are arranged on both sides of the fixed magnetic pole so as to be close to each other so that the coil portion faces the permanent magnet of the fixed magnetic pole. For example, the armature 11 includes three-phase coils (coil 11u, coil 11v, and coil 11w), and the armature 12 includes three-phase coils (coil 12u, coil 12v, and coil 12w). Are arranged so that the same phase is opposed to each other. Hereinafter, the armature 11 side will be described as A side, and the armature 12 side will be described as B side.

As shown in FIG. 3, the magnetic poles of the fixed magnetic poles are arranged so as to be shifted by 90 ° from each other by a half of one magnetic pole to control the phase of the current supplied to the armature. Accordingly, it is possible to reduce thrust unevenness in the linear motor. The thrust unevenness of the linear motor will be described with reference to FIG.

FIGS. 4A and 4B show the phase relationship between the magnetic pole on the A side and the supply current when the current having the optimum phase is supplied to the armature 11 in the configuration shown in FIG. , B respectively show the phase relationship between the magnetic poles and the supply current. Generally, the driving force F of the motor is proportional to the product of the driving current I and the cosine value of the phase difference ε between the driving current and the magnetic pole (F = k × I × cos ε). Note that k is a proportional constant. Therefore, on the A side shown in FIG.
Since the phase difference ε between the magnetic pole and the supply current is 0 °, the driving force does not decrease due to the phase difference. On the other hand, FIG.
When a current having the same phase as that on the A side is supplied on the B side shown in FIG. 2, the phase difference ε between the magnetic pole and the supplied current becomes 90 °, so that no driving force is generated due to the phase difference.

Therefore, the first linear motor control of the present invention
In the embodiment, as shown in FIGS. 4C and 4D, the phase of the current supplied to the armature is adjusted. In the first form,
Since it is assumed that an in-phase current is supplied to both armatures, the driving force generated by the phase difference ε of the current supplied to the armature 11 decreases, and the driving force generated by the phase difference ε of the current supplied to the armature 12 decreases. The two phase differences ε are distributed so that the reduction in force is equal. The distribution of the two phase differences ε is performed by distributing the 90 ° phase difference resulting from shifting the magnetic poles by 90 ° to 45 ° each. FIG.
On the A side shown in (c), the supply current is -45 with respect to the magnetic pole.
On the B side shown in FIG. 4D, control is performed to shift the supply current by + 45 ° with respect to the magnetic pole. As a result, cos (± 45 °) = 0.707, and the reduction in the driving force caused by the phase difference ε is approximately 30%.

FIG. 5 illustrates the state of the thrust unevenness in the first embodiment. The thrust unevenness on the A side shown in FIG. 5 (d) and the thrust unevenness on the B side shown in FIG. 5 (f). Thrust non-uniformity is a direction in which the phases of the fixed magnetic poles are opposite to each other due to a configuration in which the phases of the fixed magnetic poles are shifted from each other, and cancel each other. Therefore, the thrust unevenness of the thrust synthesized by both armatures is reduced.

Therefore, in the first embodiment, the thrust non-uniformity generated by the configuration in which the fixed magnetic poles are arranged with the magnetic poles shifted from each other is reduced, and the phase of the current supplied to each armature is changed. By controlling according to the phase difference between the magnetic poles, the armature can be driven and the reduction in the driving force is reduced.

FIG. 6 shows a second example of the linear motor according to the present invention when the linear motor is driven by the control system described above.
FIG. The second embodiment is a control example in the case where an in-phase current is supplied to the armature, as in the first embodiment. FIG. 6 schematically shows an arrangement of fixed magnetic poles and an armature in a linear motor. In FIG. 6, the magnetic poles of the magnet pieces including the permanent magnets 13 and 14 are arranged on both sides of the fixed magnet plate 15 with the phases thereof shifted from each other, thereby forming the same fixed magnetic pole as in the first embodiment.
Further, the armatures 11 and 12 are arranged on both sides of the fixed magnetic pole so as to be close to each other so that the coil portion faces the permanent magnet of the fixed magnetic pole, and are arranged so that the phase sequence of the coils is shifted. For example, the armature 11 is a three-phase coil (coil 1
1u, coil 11v, coil 11w), and the armature 12 has a three-phase coil (coil 12u, coil 12v,
Coil 12w). One of the three-phase coils of the armature is arranged with the phase sequence shifted. In FIG. 6, the phase sequence of the coils of each phase of the armature 12 is shifted by 120 °, and the W-phase, the V-phase and the W-phase of the
Arrange so as to be U-phase and V-phase. In the following, armature 1
A description will be given on the assumption that one side is the A side and the armature 12 side is the B side.

As shown in FIG. 6, the magnetic poles of the fixed magnetic poles are arranged so as to be shifted by 90 ° from each other by a half of one magnetic pole, and the phase of one of the three-phase coils of the armature is further shifted. By changing the order and controlling the phase of the current supplied to the armature, it is possible to reduce thrust unevenness in the linear motor. The thrust unevenness of the linear motor will be described with reference to FIG.

FIGS. 7A and 7B show the phase relationship between the magnetic pole on the A side and the supply current when the current having the optimum phase is supplied to the armature 11 in the configuration shown in FIG. , B respectively show the phase relationship between the magnetic poles and the supply current. As described above, the driving force F of the motor has a relationship (F = k × I × cos ε) proportional to the product of the driving current I and the cosine value of the phase difference ε between the driving current and the magnetic pole. Therefore, on the A side shown in FIG. 7A, the phase difference ε between the magnetic pole and the supply current is 0 °, and therefore, the driving force does not decrease due to the phase difference. On the other hand, B shown in FIG.
Side, when a current in the same phase as the A side is supplied, the phase difference ε between the magnetic pole and the supplied current becomes −30 °, and the driving force on the B side is about 8 °.
6% (= cos (−30 °)).

The above-mentioned phase difference ε = −30 ° is the phase shift obtained by shifting the phase of the fixed magnetic pole by 90 °, and
This is caused by the total phase shift of the phase sequence of the armature coil and the phase shift obtained by shifting the phase by -120 °.

Therefore, the second embodiment of the linear motor control of the present invention
In the embodiment, as shown in FIGS. 7C and 7D, the phase of the current supplied to the armature is adjusted. In the second form,
Since it is assumed that an in-phase current is supplied to both armatures, the driving force generated by the phase difference ε of the current supplied to the armature 11 decreases, and the driving force generated by the phase difference ε of the current supplied to the armature 12 decreases. The two phase differences ε are distributed so that the reduction in force is equal. The distribution of the two phase differences ε is performed by subtracting the above-mentioned combined phase difference of −30 ° from each other by (+15
(°) and (−15 °). On the A side shown in FIG. 7C, the supply current is shifted by + 15 ° phase with respect to the magnetic pole, and on the B side shown in FIG. 7D, the supply current is shifted by -15 ° phase with respect to the magnetic pole. Do. Thus, cos (± 15 °) = 0.96
6, the reduction in the driving force caused by the phase difference ε is approximately 3%.

In FIGS. 7B and 7D, the armature 1
Since the phase order of the coils on the two sides is shifted, the current Iw for the W phase is indicated by a dashed line, and the current Iu for the U phase is indicated by a solid line and a broken line.

Thus, even in the second embodiment, A
The non-uniform thrust on the side and the non-uniform thrust on the B side have opposite phases due to the configuration in which the phases of the fixed magnetic poles are shifted from each other, and are in directions canceling each other. Therefore, the thrust unevenness of the thrust synthesized by both armatures is reduced.

Therefore, in the second embodiment, the non-uniform thrust generated by the configuration in which the fixed magnetic poles are arranged with the phases of the magnetic poles shifted from each other is reduced, and the phase of the current supplied to each armature is changed. By controlling according to the phase difference between the magnetic poles, it is possible to drive the armature and reduce the reduction of the driving force. The decrease in force can be further reduced.

The above-described first and second embodiments are:
As shown in FIGS. 1 and 2, the control system is configured to supply an in-phase current to coils of a plurality of linear motors. On the other hand, a third mode for supplying out-of-phase currents to coils of a plurality of linear motors will be described next.

In the third embodiment of the present invention, for example, a control system shown in FIG. 8 is configured to supply currents of different phases to the coils of a plurality of linear motors. Of different current supply.

In the current control shown in FIG. 8, a plurality of control systems (systems a and b surrounded by broken lines in FIG. 2) having the phase current command block 2, the amplifier 3, and the linear motor 4 are provided. The three-phase command conversion block 1 and the magnetic pole detector 5 are provided only in one control system, and the three-phase commands generated by one three-phase command conversion block 1 are transmitted to the phase current command blocks 2 (the first phase) of each control system. Current command block 2a, second
The phase shift block 6 is supplied between each phase current command block 2 and each amplifier 3 (first amplifier 3a, second amplifier 3b).
(A first phase shift 6a and a second phase shift 6b). The phase shift block 6 adjusts the phase of the phase current command formed by the phase current command block 2 and supplies the same to the amplifier 3, thereby individually controlling the phase of the current supplied to each linear motor. , Different phases of current can be supplied.

FIG. 4E shows a case where the third embodiment is applied to the linear motor having the structure shown in FIG.
This will be described with reference to FIG. FIG. 4E shows a case where the current supply to the armature on the A side is controlled by the phase shift block 6 so that the phase difference ε thereof becomes 0 ° corresponding to the phase of the magnetic pole. This makes it possible to perform normal driving of the linear motor and prevent a reduction in driving force based on the phase difference. FIG. 4F shows a case where the current supply to the B-side armature is controlled by the phase shift block 6 so that the phase difference ε thereof becomes 0 ° corresponding to the phase of the magnetic pole. The phase shift block 6 supplies a current that has been subjected to phase control to delay the phase supplied by 90 ° with respect to the current supplied to the A side. This makes it possible to perform normal driving of the linear motor also on the B side and prevent a decrease in driving force based on the phase difference.

FIGS. 7 (e) and 7 (f) are diagrams illustrating a case where the third embodiment is applied to the linear motor having the configuration shown in FIG. FIG. 7E shows the case where the current supply is controlled by the phase shift block 6 for the armature on the A side so that the phase difference ε thereof becomes 0 ° corresponding to the phase of the magnetic pole. This makes it possible to perform normal driving of the linear motor and prevent a reduction in driving force based on the phase difference. FIG. 7F shows a case where the current supply to the B-side armature is controlled by the phase shift block 6 so that the phase difference ε thereof becomes 0 ° corresponding to the phase of the magnetic pole. The phase shift block 6 supplies a current that has been subjected to phase control to delay the phase of the current supplied to the A side. Since the phase sequence of the coil on the armature 12 side is shifted, the phase control is performed by shifting the current supplied to the A side by 30 °. This makes it possible to perform normal driving of the linear motor also on the B side and prevent a decrease in driving force based on the phase difference.

In FIG. 7 (f), since the phase order of the coils on the armature 12 side is shifted, the current Iw for the W phase is changed.
Is indicated by a dashed line, and the current Iu for the U phase is indicated by a broken line.

Hereinafter, an example of the result of implementation by the linear motor and the control method of the present invention will be described. 9 to 12 show one embodiment of the thrust and the speed when the linear motor is driven at a feed speed of 12000 mm / min. FIGS. 9 and 10 show the thrust and the conventional configuration in which the phases of the fixed magnetic poles are not shifted. FIG. 11 and FIG. 12 show the thrust and the speed according to the configuration of the present invention in which the phases of the fixed magnetic poles are shifted. FIGS. 11 and 12 show examples in which the magnetic poles are shifted by half of one magnetic pole of the fixed magnet.

As shown in FIG. 9, in the linear motor having the conventional configuration, the amplitude of the thrust is 14.3 N,
As shown in FIG. 11, in the linear motor having the configuration of the present invention,
The amplitude of the thrust is 5.6 N, and the effect of reducing the uneven thrust can be confirmed by the configuration of the linear motor according to the present invention.

Further, as shown in FIG. 10, in the linear motor having the conventional configuration, the fluctuation width of the speed is 55.3 mm / min.
On the other hand, as shown in FIG. 12, in the linear motor having the configuration of the present invention, the fluctuation in speed is 13.8 mm / mi.
n, and by the configuration of the linear motor according to the present invention,
The effect of reducing the uneven speed can be confirmed.

[0046]

As described above, according to the present invention,
Thrust unevenness in the linear motor can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram for explaining a control system for driving a linear motor according to the present invention.

FIG. 2 is a block diagram for explaining another control system for driving the linear motor of the present invention.

FIG. 3 is a diagram illustrating a first embodiment of the linear motor of the present invention.

FIG. 4 is a diagram for explaining a relationship between a magnetic pole and a supply current according to the first embodiment of the present invention.

FIG. 5 is a diagram illustrating a state of thrust unevenness according to the first embodiment of the present invention.

FIG. 6 is a diagram for explaining a relationship between a magnetic pole and a supply current according to the second embodiment of the present invention.

FIG. 7 is a diagram illustrating a state of uneven thrust according to the second embodiment of the present invention.

FIG. 8 is a block diagram for explaining another control system for driving the linear motor of the present invention.

FIG. 9 is a thrust characteristic diagram of a conventional linear motor.

FIG. 10 is a speed characteristic diagram of a conventional linear motor.

FIG. 11 is a thrust characteristic diagram of the linear motor of the present invention.

FIG. 12 is a speed characteristic diagram by the linear motor of the present invention.

FIG. 13 is a schematic perspective view of a linear motor.

FIG. 14 is a conventional control system diagram of a linear motor.

FIG. 15 is another control system diagram of a conventional linear motor.

FIG. 16 is a diagram illustrating an arrangement of fixed magnetic poles and an armature in a linear motor.

FIG. 17 is a diagram illustrating thrust unevenness of a linear motor.

FIG. 18 is a diagram illustrating thrust unevenness of a linear motor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Three phase command conversion block 2, 2a, 2b Phase current command block 3, 3a, 3b Amplifier 4, 4a, 4b Linear motor 5 Magnetic pole detector 6, 6a, 6b Phase shift 11, 12 Armature 11u, 11v, 11w, 12u, 12v, 12w Coil 13, 14 Permanent magnet 15 Fixed magnet plate

Claims (8)

[Claims] 1. A magnet plate having a large number of magnet pieces extending on both sides thereof in one axial direction, opposed to both sides of the magnet plate via an action gap, and a magnetic field and electromagnetic interaction by the magnet pieces. And a pair of armatures that are integrally movable in the axial direction with respect to the magnet plate, wherein the magnet pieces on both sides of the magnet plate shift their magnetic poles out of phase with each other. A linear motor characterized by being arranged in a vertical position. 2. A magnet plate having a large number of magnet pieces extending on both sides thereof in one axial direction, and opposed to both sides of the magnet plate via an action gap, and a magnetic field and electromagnetic interaction by the magnet pieces are provided. And a pair of armatures that are integrally movable in the axial direction with respect to the magnet plate, wherein the magnet pieces on both sides of the magnet plate shift their magnetic poles out of phase with each other. Wherein the phase sequence of the windings of the pair of armatures is shifted from each other. 3. The phase shift of the magnetic pole is caused by a thrust unevenness generated by an electromagnetic interaction between the magnetic pole of one magnet piece and the armature facing the armature and the armature facing the magnetic pole of the other magnet piece. 3. A linear motor according to claim 1, wherein the thrust non-uniformity generated by the electromagnetic interaction is reversed in phase. 4. The linear motor according to claim 1, wherein the phase of the magnetic pole of one of the magnet pieces is shifted from the magnetic pole of the other magnet piece by a half of one magnetic pole. 5. A magnet plate in which a large number of magnet pieces are extended on both sides in one axial direction, and the magnetic poles on each side are arranged out of phase with each other; A pair of armatures having a pair of armatures having a pair of windings for performing electromagnetic interaction with a magnetic field generated by the magnet pieces and being integrally movable with respect to the magnet plate in the axial direction; To supply a common-mode current to the
The magnitude of the phase shift between the magnetic field generated in one armature winding by the current and the magnetic field generated by the facing magnet piece and the magnetic field generated by the magnetic field generated by the facing magnet piece and the magnetic field generated in the other armature winding by the current A method for controlling a linear motor, wherein the magnitude of a phase shift is controlled to be equal. 6. The linear motor control method according to claim 5, wherein the pair of armatures shift the phase sequence of windings from each other. 7. A magnet plate in which a large number of magnet pieces are extended on both sides in one axial direction, and the magnetic poles on each side are arranged out of phase with each other; A pair of armatures having a pair of armatures having a pair of windings for performing electromagnetic interaction with a magnetic field generated by the magnet pieces and being integrally movable with respect to the magnet plate in the axial direction; Supplying an out-of-phase current to the armature, and controlling the phase of the current supplied to each armature so that the magnetic field generated in the armature winding by the current and the magnetic field generated by the facing magnet piece are in phase with each other. A method for controlling a linear motor, comprising: 8. The linear motor control method according to claim 7, wherein the pair of armatures shifts a phase sequence of windings from each other.