JP2004364374A - Linear motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high precision linear motor capable of reducing generation of cogging thrust as much as possible. <P>SOLUTION: The linear motor comprises a field pole 2 consisting of a field yoke 2a where a plurality of permanent magnets 2b are arranged linearly, and an armature 1 arranged to face the row of permanent magnets 2b in the field pole 2 through a magnetic air gap. The armature 1 comprises an armature core 3 having main teeth 4b and slots 4c, an armature winding 7 formed by winding a coil in the slots 4c of the armature core 3, and auxiliary teeth 5 arranged at the opposite ends of the armature core 3 in the direction parallel with the row of the permanent magnets 2b in the field pole 2 wherein any one of the field pole 2 or the armature 1 serves as a stator and the other serves as a moving member so that the field pole 2 and the armature 1 travel relatively. In such a linear motor, shape of the auxiliary teeth 5 at the opposite ends of the armature core 3 is differentiated depending on the length of the armature core 3 in the direction parallel with the row of the permanent magnets 2b in the field pole 2 or the number of main teeth 4b of the armature 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a high-precision linear motor used for table feed of a machine tool, and particularly to an armature structure thereof.
[0002]
[Prior art]
FIG. 7 shows a sectional side view of a gap-facing linear motor according to the prior art. In FIG. 7, 1 is an armature and 2 is a field pole.
The armature 1 includes a so-called split core type armature core 3 including a plurality of armature blocks 4, and auxiliary teeth 5 provided at both ends of the armature core 3. The armature block 4 is formed by laminating a plurality of substantially rectangular electromagnetic steel sheets, and has an armature winding 7 wound around a slot 4c of a core block 4a having a slot 4c and a main tooth 4b. This is a configuration in which a convex engaging portion 6a is provided and a concave engaging portion 6b is provided on the other side surface. The auxiliary tooth 5 is made of a substantially L-shaped laminated steel plate or a steel member, and has a convex engaging portion 6a on the side surface of the auxiliary tooth 5 at one end and a concave engaging portion on the side surface of the auxiliary tooth 5 at the other end. 6b is provided. The plurality of armature blocks 4 and the auxiliary teeth 5 are arranged in a straight line, and the engaging portions 6a and 6b adjacent to each other are fitted together and fixed, and then fixed to the lower surface of the moving member 8. Note that, instead of the split core type armature 1, an armature of an integrated core made of a laminated steel plate in which the armature core 3 or the auxiliary teeth 5 are additionally extracted in a comb-tooth shape in addition to the armature core 3 may be configured. .
The field pole 2 is arranged adjacent to a field yoke 2a fixed to a fixed portion (not shown) so that a plurality of permanent magnets 2b are alternately different in polarity.
A linear motor is configured such that the armature 1 and the field pole 2 face each other in parallel with a gap therebetween.
In the linear motor having such a configuration, since the configuration of the armature 1 is as described above, the number of laminated steel plates of the armature core 3 is increased or decreased to change the stacking thickness, or the number of the armature blocks 4 is increased or decreased. By doing so, the generated thrust of the linear motor can be freely designed.
In addition, only the armature core 2 excluding the auxiliary teeth 5 has different interlinkage magnetic fluxes between the main teeth 4b at both ends of the armature core 3 and the main teeth 4b at the center, and thus the force acting on each main tooth 4b. Variation and cogging thrust occur. To prevent this, an auxiliary tooth 5 is provided (Patent Document 1). In addition, the relationship between the pitch of the field pole 2 and the length of the auxiliary teeth 5 that minimizes the cogging thrust, and the relationship between the length of the main teeth 4b and the length of the auxiliary teeth 5 are represented by numerical values using theoretical formulas and finite element methods. Investigations have been made to reduce the cogging thrust as much as possible by analysis (Patent Documents 2 and 3).
[0003]
[Patent Document 1] Japanese Patent Publication No. 60-30195 [Patent Document 2] WO 01/80408 [Patent Document 3] Japanese Utility Model Publication No. 7-53427
[Problems to be solved by the invention]
However, in applying a conventional linear motor to a machine tool where contouring performance is important or a semiconductor device that performs fine positioning at high speed, the following problems occur in the actually manufactured linear motor. was there.
As described above, the shape of the auxiliary teeth of the armature core is determined by numerical analysis or the like. For an equivalent armature core having electromagnetic periodicity and similarity, the auxiliary shape of the same shape is designed from the viewpoint of design or cost. Teeth are used. Here, having electromagnetic periodicity means that the number of main teeth of the armature core is an integral multiple. As a result, the armature core lengthens in the stroke direction.
Further, the electromagnetic similarity means that the armature core shape and the like are the same and the stacking thickness is different. Thereby, the armature core becomes longer and shorter in the direction perpendicular to the stroke direction.
However, even if there is an electromagnetic periodicity or similarity, when the shape of the armature core changes, the electromagnetic end effect in the stroke direction or in the direction perpendicular thereto changes. Therefore, due to the effect of the change of the end effect, the effect of suppressing the variation of the force acting on the main teeth by the auxiliary teeth is reduced, and the balance of the electromagnetic force acting on the teeth due to the field poles is lost, so that the cogging thrust and thrust ripple are reduced. And, consequently, deteriorating contouring performance or positioning performance of a machine tool or a semiconductor device incorporating a linear motor, which has been a serious problem.
The present invention has been made to solve the above-described problem, and the generation of cogging thrust is minimized by mounting auxiliary teeth having different shapes to armature cores having electromagnetic periodicity and similarity. It is an object of the present invention to provide a highly accurate linear motor that can be reduced.
[0005]
[Means for Solving the Problems]
In order to solve the above problem, the present invention according to claim 1 includes a field pole composed of a field yoke in which a plurality of permanent magnets are arranged linearly so as to have alternately different polarities, and a permanent magnet array of the field poles. And an armature arranged to face each other with a magnetic gap therebetween, wherein the armature has an armature core having a main tooth and a slot, and an armature winding having a coil wound around a slot of the armature core. And the auxiliary teeth arranged at both ends of the armature core in the direction parallel to the permanent magnet rows of the field poles, one of the field poles and the armature being a stator, and the other being a stator. As a mover, in a linear motor in which the field pole and the armature run relatively, a length of the armature core in a direction parallel to a row of permanent magnets of the field pole, or a main tooth of the armature is used. By the number of Shape of the auxiliary teeth of the armature core ends are different.
Further, according to the invention of claim 2, the shape of the auxiliary teeth at both ends of the armature core differs depending on the length of the field poles of the armature core in the direction perpendicular to the permanent magnet row.
According to a third aspect of the present invention, in the first or second aspect, the armature core includes a plurality of split cores, and has a convex shape on one side surface of a yoke portion forming the split core. The present invention according to claim 4, wherein the joining portion is provided with a concave engaging portion on the other side surface, and the adjacent engaging portions are fitted to each other so as to be joined together. A field pole in which two field yokes in which magnets are arranged linearly are arranged facing each other; and an armature arranged so as to face through a magnetic gap between the two field poles, An armature core having main teeth and slots at both ends in a direction orthogonal to the permanent magnet row of the field poles; an armature winding having coils wound around slots at both ends of the armature core; Auxiliary tapes arranged at both ends of the field poles in the direction parallel to the permanent magnet row A linear motor that is configured to have one of the field pole and the armature as a stator and the other as a mover so that the field pole and the armature run relatively. The shape of the auxiliary teeth at both ends of the armature core is changed depending on the length of the armature core in the direction parallel to the permanent magnet rows of the field poles or the number of main teeth of the armature.
According to a fifth aspect of the present invention, in the invention of the fourth aspect, the shape of the auxiliary teeth at both ends of the armature core is changed depending on the length of the field poles of the armature core in the direction perpendicular to the permanent magnet row. .
According to a sixth aspect of the present invention, in the invention of the fourth or fifth aspect, the armature core is constituted by a plurality of divided cores, and the armature core has a convex shape on one side surface of the yoke portion constituting the divided core. It is assumed that the joining portion is provided with a concave engaging portion on the other side surface, and each of the adjacent engaging portions is fitted and joined.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a linear motor of the present invention will be described based on an embodiment shown in the drawings.
[0007]
(First embodiment)
The same components as those of the prior art are denoted by the same reference numerals, and the description thereof will be omitted.
FIG. 1 shows a gap-facing linear motor according to the present invention. FIG. 2 is an enlarged view of the periphery (in the frame of the dashed line) of the auxiliary teeth 5 on one side (right side) of FIG.
The linear motor according to the present invention has a similar shape to the linear motor according to the prior art shown in FIG. 7, but has a different stacking thickness (dimensions in the depth direction of the paper surface), and additionally has a different shape of the auxiliary teeth 5. The rest is the same as the configuration described in the related art.
More specifically, the linear motor of the present invention in the embodiment of FIG. 1 has a stacking thickness shorter than that of the conventional example of FIG. 7 (for example, half the stacking thickness), and the electromagnetic end effect in the stacking direction is remarkable. Become. In order to maximize the effect of reducing the cogging of the auxiliary teeth 5 of the end effect, for example, the dimension B of the auxiliary teeth 5 shown in FIG. 2, that is, the length of the auxiliary teeth 5 is made longer than before.
The linear motor having the armature 1 configured as described above acts to minimize the variation in the force generated by the main teeth 4b due to the field yoke 2a due to the end effect generated in the armature 1, and thus cogging. Thrust can be minimized.
[0008]
(Second embodiment)
Next, FIG. 3 shows a second embodiment. The difference between the linear motor of the second embodiment and the linear motor of the first embodiment is that the number of the armature blocks 4 of the armature core 3 of the linear motor of the first embodiment is nine. On the other hand, the number of the armature blocks 4 of the armature core 3 of the linear motor of the second embodiment is twice as large as 18 (periodically the same), and the shape of the auxiliary teeth 5 is different. The stacked thicknesses of both are the same, and the generated thrust of the linear motor is twice as large as that of the first embodiment.
The end effect of the end portion in the stroke direction of the linear motor of the configuration of the second embodiment and the linear motor of the first embodiment are different, and the end effect of the end portion in the stroke direction is smaller in the second embodiment. Become. Therefore, the linear motor of the second embodiment has a configuration in which, for example, the dimension B of the auxiliary teeth 5 shown in FIG. 2, that is, the length of the auxiliary teeth 5 is shorter than that of the first embodiment.
As in the first embodiment, the linear motor having the armature 1 configured as described above minimizes the variation in the generation force of the main teeth 4b by the field yoke 2a due to the end effect generated in the armature 1. It acts so as to suppress the cogging thrust.
[0009]
(Third embodiment)
FIGS. 4 and 6 show a third embodiment in which the present invention is applied to a magnetic flux penetrating linear motor in which the armature 1 is arranged via a magnetic gap so as to face between two field poles 2. Is shown. FIG. 5 is an enlarged view of the periphery of the auxiliary teeth 5 on one side (right side) in FIGS. 4 and 6 (within the dashed line frame).
The linear motor of the magnetic flux penetration type shown in FIGS. 4 and 6 has two field poles 2, and the armature 1 between the two field poles 2 has main teeth 4b and slots 4c above and below a core block 4a. And the armature winding 7 is wound around both the upper and lower slots 4c. The point that the thrust is generated on the two magnetic gap surfaces is greatly different from the gap facing type. In addition, the configuration is such that a mover (not shown) is coupled to the mover by a mover mounting hole 8a. Other basic configurations are the same as those of the gap-facing linear motor of FIG.
The two linear motors shown in FIGS. 4 and 6 are the same as those described in the second embodiment. The difference between the linear motor shown in FIG. 4 and the linear motor shown in FIG. The number of the armature blocks 4 of the armature core 3 of the linear motor of FIG. 6 is twice as large as 18 while the number of the armature blocks 4 of the armature core 3 of FIG. ), The shape of the auxiliary teeth 5 is different. 6 are the same, and the generated thrust of the linear motor is twice as large as that of FIG. 4.
The end effect at the end in the stroke direction of the linear motor having the configuration shown in FIG. 6 is different from that of the linear motor shown in FIG. 4, and the end effect at the end in the stroke direction is smaller in FIG. Therefore, the linear motor of FIG. 6 has a configuration in which, for example, the dimension B of the auxiliary teeth 5 shown in FIG. 5, that is, the length of the auxiliary teeth 5 is shorter than that of the linear motor of FIG.
The linear motor configured as described above can obtain the same operation and effect as those described in the second embodiment.
Also, in the magnetic flux penetrating linear motors of FIGS. 4 and 6, as described in the first embodiment, different auxiliary teeth dimensions and different By doing so, a linear motor capable of reducing cogging thrust as much as possible can be realized.
[0010]
In the first and second embodiments, only the B dimension of the auxiliary teeth 5 is different, but the A dimension, that is, the center line of the main teeth at both ends of the armature core 3 and the center line of the auxiliary teeth 5 are used. The dimension between them and the dimension C, that is, the width of the auxiliary teeth 5 may be different.
In each embodiment, the armature core structure has been described as a split core type, but the same applies to an integral core type. Although the teeth are semi-open slots, they may be open slots.
[0011]
【The invention's effect】
As described above, according to the present invention, by providing the auxiliary teeth corresponding to the end effect in the stroke direction of the armature core or in the direction perpendicular to the stroke direction, the main teeth caused by the electromagnetic end effects are provided. The imbalance of the forces acting on the linear motor can be reduced as much as possible, and the cogging thrust of the linear motor can be minimized.
As described above, there is a great effect that a machine tool having high contouring performance and capable of high-precision processing and a linear motor capable of performing fine positioning at high speed and applicable to a high-throughput semiconductor manufacturing apparatus can be provided.
[Brief description of the drawings]
FIG. 1 is a side sectional view of a linear motor according to a first embodiment of the present invention.
FIG. 2 is an enlarged view of a periphery of an auxiliary tooth of FIG. 1;
FIG. 3 is a side sectional view of a linear motor showing a second embodiment of the present invention.
FIG. 4 is a plan sectional view of a linear motor according to a third embodiment of the present invention.
FIG. 5 is an enlarged view of a part around the auxiliary teeth of FIG. 4;
FIG. 6 is a plan sectional view of another linear motor according to a third embodiment of the present invention.
FIG. 7 is a side sectional view of a conventional linear motor.
[Explanation of symbols]
Reference Signs List 1 armature 2 field pole 2a field yoke 2b permanent magnet 3 armature core 4 armature block 4a core block 4b main tooth 4c slot 5 auxiliary tooth 6a convex engagement portion 6b concave engagement portion 7 armature winding 8 move Child 8a Slider mounting hole

Claims (6)

A field pole (2) composed of a field yoke (2a) in which a plurality of permanent magnets (2b) are arranged in a line so as to have alternately different polarities, and a row of permanent magnets (2b) of the field pole (2). An armature (1) disposed so as to face through a magnetic gap,
The armature (1) includes an armature core (3) having a main tooth (4b) and a slot (4c), and an armature winding having a coil wound around a slot (4c) of the armature core (3). (7) and auxiliary teeth (5) arranged at both ends of the armature core (3) in the direction parallel to the row of the permanent magnets (2b) of the field poles (2),
One of the field pole (2) and the armature (1) is used as a stator and the other is used as a mover so that the field pole (2) and the armature (1) run relatively. Linear motor
The length of the armature core (3) in the direction parallel to the row of the permanent magnets (2b) of the field poles (2) or the number of the main teeth (4b) of the armature (1) depends on the armature core ( 3) A linear motor characterized in that the shapes of the auxiliary teeth (5) at both ends are different. The shape of the auxiliary teeth (5) at both ends of the armature core (3) differs depending on the length of the armature core (3) in the direction perpendicular to the row of the permanent magnets (2b) of the field poles (2). The linear motor according to claim 1, wherein The armature core (3) is composed of a plurality of split cores, and has a convex engaging portion (6a) on one side of a yoke portion forming the split core and a concave engaging portion on the other side. The linear motor according to claim 1 or 2, wherein a portion (6b) is provided, and each adjacent engaging portion is fitted and connected. Between a field pole (2) in which two field yokes (2a), in each of which a plurality of permanent magnets (2b) are arranged in a line so as to have alternately different polarities, face each other, and the two field poles (2); And an armature (1) arranged so as to be opposed via a magnetic air gap,
The armature (1) includes an armature core (3) having main teeth (4b) and slots (4c) at both ends in a direction orthogonal to the row of the permanent magnets (2b) of the field poles (2); An armature winding (7) having coils wound around slots at both ends of a core (3), and two ends of the armature core (3) in the direction parallel to the row of permanent magnets (2b) of the field poles (2). It is composed of the auxiliary teeth (5) arranged,
One of the field pole (2) and the armature (1) is used as a stator and the other is used as a mover so that the field pole (2) and the armature (1) run relatively. Linear motor
The length of the armature core (3) in the direction parallel to the row of the permanent magnets (2b) of the field poles (2) or the number of the main teeth (4b) of the armature (1) depends on the armature core ( 3) A linear motor characterized in that the shapes of the auxiliary teeth (5) at both ends are different. The shape of the auxiliary teeth (5) at both ends of the armature core (3) differs depending on the length of the armature core (3) in the direction perpendicular to the row of the permanent magnets (2b) of the field poles (2). The linear motor according to claim 4, wherein The armature core (3) is composed of a plurality of split cores, and has a convex engaging portion (6a) on one side of a yoke portion forming the split core and a concave engaging portion on the other side. The linear motor according to claim 4 or 5, wherein a portion (6b) is provided, and each adjacent engaging portion is fitted and connected.

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