JP3944766B2 - Permanent magnet synchronous linear motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a permanent magnet type synchronous linear motor used in a FA system, for example, a table feed of a machine tool or a stepper drive mechanism of a semiconductor manufacturing apparatus.
[0002]
[Prior art]
FIG. 4 shows a permanent magnet type synchronous linear motor conventionally used in a transport system for FA equipment, for example, a table feed of a machine tool or a stepper drive mechanism of a semiconductor manufacturing apparatus. FIG. 4 is a side sectional view of a conventional permanent magnet type synchronous linear motor. In this linear motor, an explanation will be given using an example in which an 8-pole 9-slot is a basic configuration, and the armature 2 is moved relative to the mover and the field 1 is a stator.
In the figure, 1 is a field magnet, 11 is a flat field yoke, 12 is a plurality of permanent magnets attached to the field yoke 11 so as to have different polarities alternately, and 2 is a permanent magnet 12 via a magnetic gap. The armatures 21 are opposed to each other, 21 is an armature core, which is formed by laminating steel plates having main teeth 21b forming slots 21a and yoke portions 24 connecting the main teeth 21b. It is fixed. Reference numeral 22 denotes an armature winding wound and accommodated in the slot 21a. Auxiliary teeth 23 provided at both ends of the armature core 21 are provided with means for reducing cogging thrust generated by the end effects at both ends of the armature core.
[0003]
FIG. 5 is a diagram showing a cogging thrust waveform of a conventional permanent magnet type synchronous linear motor. Like the cogging thrust waveform shown in FIG. 5, the length Ht of the main teeth 21b and the auxiliary are based on the condition that the cogging thrust F1 acting on the main teeth 21b and the cogging thrust F2 acting on the auxiliary teeth 21a are F1 + F2≈0. The length Hd of the tooth 23 is set in the range of 0 <Hd <Ht, and the tooth width Bd of the auxiliary tooth 21a and the tooth width Bt of the main tooth 21b are set in the range of Bd <Bt. Under the above-described conditions, the linear motor can minimize the cogging thrust (for example, Japanese Patent Application No. 2000-118022).
[0004]
[Problems to be solved by the invention]
However, in the prior art, in order to reduce the cogging thrust, means such as canceling the end effect of the armature core end or suppressing the effect of the end effect are taken. However, in the actual machine, the cogging thrust is not necessarily reduced. There is a problem that it cannot be done.
That is, when designing the linear motor, use the design values such as the shape and size of the main teeth, the magnetic air gap length between the field and the armature, and the representative values of the magnetic characteristics of the permanent magnet used for the field. The conditions for minimizing the cogging thrust are obtained, and the shape dimensions of the auxiliary teeth are determined. However, the actually manufactured linear motor has a dimensional variation and error when the armature core is punched, a magnetic gap dimension error when combining the field and the armature, and a permanent magnet fixed to the field yoke. Due to dimensional variations and errors, variations in the magnetic properties of magnetic members such as armature cores, field yokes, and permanent magnets, and differences from typical values, the dimensional conditions where the cogging thrust becomes almost zero shifts and the cogging thrust increases. End up.
For this reason, in order to manufacture a linear motor with small cogging thrust close to the design value, it is reduced by repeated design and manufacturing based on actual shape measurement and evaluation of cogging thrust. The dimensional variations and errors during the assembly of the members, the variations in the magnetic characteristics of the magnetic members, and the differences from the representative values differ from case to case, and cannot be easily solved.
The present invention has been made to solve the above-described problems, and does not depend on repeated evaluation work by design and manufacture when evaluating the cogging thrust of a linear motor, and does not depend on the actual dimensions of the actual machine or the actual magnetism of the magnetic member. An object of the present invention is to provide a permanent magnet type synchronous linear motor that can easily reduce the cogging thrust even if the characteristic deviates from the design value.
[0005]
[Means for Solving the Problems]
In order to solve the above problem, the present invention of claim 1 is characterized in that a first field magnet in which a plurality of permanent magnets are arranged in a straight line on the first field yoke so as to alternately have different polarities, A first armature disposed so as to be opposed to one field through a magnetic gap, the first armature includes a first armature core having a main tooth and a slot, and the first armature. A first armature winding in which a coil is wound around a slot of one armature core, and a mover that relatively moves one of the first field and the first armature; In the permanent magnet type synchronous linear motor having the other as a stator, the first armature is a cogging thrust that changes with the mover relative to a position excluding the side facing the first field. Vibration force generating means for generating a vibration force having the same period as the cogging thrust is provided. Is.
According to a second aspect of the present invention, in the permanent magnet synchronous linear motor according to the first aspect, the vibration force generating means is a surface excluding a surface facing the first field in the first armature. A second field magnet in which a plurality of permanent magnets having different polarities are arranged alternately on a second field yoke provided on the second field yoke, and a second field magnet disposed opposite to the second field magnet via a magnetic gap. The second armature includes a slotless second armature core, and a second armature winding in which an air-core coil is wound around the second armature core. When the magnetic pole pitch of the first field is τm1 and the magnetic pole pitch of the second field is τm2, the relationship is τm2 = τm1 × 1/2.
According to a third aspect of the present invention, in the permanent magnet type synchronous linear motor according to the first aspect, the vibration force generating means is a surface excluding a surface facing the first field in the first armature. And a second armature disposed opposite to the comb core via a magnetic gap, the second armature being a slotless second core. And a second armature winding in which an air-core coil is wound around the second armature core, and the tooth pitch of the main teeth is τs1, and the comb-shaped core has the tooth pitch When the tooth pitch of the teeth is τs2, the relationship is τs1 = τs2, the magnetic pole pitch of the first field is τm1, and the magnetic pole pitch of the second armature winding is τm2. τm2 = τm1 × 1/2 .
Further, the invention of claim 4, the permanent magnet type synchronous linear motor according to claim. 1 are arranged auxiliary teeth on the end of the first armature core, said first of said auxiliary teeth The length of the auxiliary teeth is 0 when the length in the direction perpendicular to the longitudinal direction of the field is Hd and the length of the main teeth in the direction perpendicular to the longitudinal direction of the first field is Ht. <Hd <Ht is set.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[First embodiment]
FIG. 1 is a sectional side view of a permanent magnet type synchronous linear motor of the present invention.
Constituent elements of the present invention that are the same as those of the prior art will be given the same reference numerals and explanation thereof will be omitted, and only different points will be described. The linear motor according to the first to third embodiments shows an example of an 8-pole, 9-slot gap facing type as in the prior art. The setting of the range of the length Ht of the main teeth and the length Hd of the auxiliary teeth and the setting of the range of the teeth width Bt of the main teeth and the teeth width of the auxiliary teeth are the same as in the prior art.
In the figure, 3 is a vibration force generating means, 31 is a second field magnet, 31a is a second field yoke, 31b is a permanent magnet, 32 is a second armature, 32a is a second armature core, and 32b. Is a second armature winding.
The present invention is different from the prior art as follows.
That is, the first armature 2 is a first armature that moves relative to the first field 1 (stator) to a position (opposite side) excluding the side facing the first field 1. 2 is provided with a vibration force generating means 3 for generating a vibration force having the same cycle as that of the cogging thrust so that the cogging thrust changing with the movable element 2 can be canceled. The vibration force is generated electromagnetically by exciting with current.
Specifically, the vibration force generation means 3 according to the present embodiment is a second field provided on the surface (opposite side) of the first armature 2 excluding the surface facing the first field 1. From a second field 31 in which a plurality of permanent magnets 31b having different polarities are alternately arranged on a magnetic yoke 31a, and a second armature 32 arranged opposite to the second field 31 via a magnetic gap. Composed. The second armature 32 includes a slotless second armature core 32a, and a second armature winding 32b in which an air core coil is wound around the second armature core 32a. When the magnetic pole pitch of the first field 1 is τm1 and the magnetic pole pitch of the second field 31 is τm2, τm2 = τm1 × 1/2. For convenience, the magnetic pole pitch of the second armature winding is not shown.
[0007]
Next, the operation will be described.
When the linear motor is moved in the longitudinal direction of the first field 1, the cogging thrust changes with the movement of the first armature 2 that moves relatively, but the first field in the first armature 2 is changed. When a slight direct current is supplied to the vibration force generating means 3 provided on the surface (opposite side) excluding the surface facing 1, the vibration force generating means 3 generates a vibration force having the same cycle as the cogging thrust, and linear The cogging thrust of the entire motor is reduced. At this time, since the vibration force generating means 3 is not installed on the first field 1 side of the first armature 2, the action of the vibration force generating means 3 affects the effective thrust as a linear motor. do not do.
[0008]
Since the first embodiment has the above-described configuration, the magnitude of the cogging thrust generated between the first field 1 and the first armature 2 even when the cogging thrust becomes larger than the design value. The cogging thrust can be returned to the minimum value which is the design value by energizing the second armature 2 with the direct current adjusted to the above by operating the vibration force generating means 3.
This eliminates the need for repeated evaluation and design work when evaluating the cogging thrust of a linear motor, and easily reduces the cogging thrust even if the actual machine geometry and the actual magnetic characteristics of the magnetic member deviate from the design values. It is possible to provide a permanent magnet type synchronous linear motor that can be used.
Further, since the field generating source of the vibration force generating means 3 is the permanent magnet 12, no excitation current for generating the second field is required, so that an increase in power loss accompanying the addition of the vibration force generating means 3 is achieved. And temperature rise can be further suppressed.
Further, the configuration in which the auxiliary teeth 23 are provided as in this example has a smaller cogging thrust than that in which the auxiliary teeth are not provided, so that less power is supplied to the vibration force generating means 3, and vibration force generation is possible. An increase in power loss and temperature rise due to the addition of the means 3 can be suppressed.
[0009]
[Second Embodiment]
Next, a second embodiment of the present invention will be described.
FIG. 2 is a sectional side view of a permanent magnet type synchronous linear motor showing a second embodiment of the present invention.
In the figure, 33 is a comb-like core.
The second embodiment is different from the first embodiment as follows.
That is, the vibration force generating means 3 includes a comb-shaped core 33 having slots provided on the surface (opposite side) of the first armature 2 excluding the surface facing the first field 1, and the comb-shaped core 33. And a second armature 32 arranged opposite to each other with a magnetic air gap therebetween. The second armature 32 is divided into a slotless second armature core 32a and a second armature core 32a. When the tooth pitch of the main teeth 21b is τs1 and the teeth pitch of the teeth of the comb-shaped core 33 is τs2, the τs1 = τs2. It has a relationship. Although not shown, when the magnetic pole pitch of the first field 1 is τm1 and the magnetic pole pitch of the second armature winding 32b is τm2, there is a relationship of τm2 = τm1 × 1/2. It has become a thing. Since the operation is the same as that of the first embodiment, the description thereof is omitted.
[0010]
Since the second embodiment has the above-described configuration, the magnitude of the cogging thrust generated between the first field 1 and the first armature 2 even when the cogging thrust becomes larger than the design value. The cogging thrust can be returned to the minimum value, which is the design value, by energizing the second armature 32 with the direct current adjusted to
This eliminates the need for repeated evaluation and design work when evaluating the cogging thrust of a linear motor, and easily reduces the cogging thrust even if the actual machine geometry and the actual magnetic characteristics of the magnetic member deviate from the design values. It is possible to provide a permanent magnet type synchronous linear motor that can be used.
Further, since no permanent magnet is used for the vibration force generating means 3, it is possible to suppress an increase in cost due to the addition of the vibration force generating means 3 and an increase in the number of assembly steps represented by the attachment of the permanent magnet.
[0011]
[Third embodiment]
Next, a third embodiment of the present invention will be described.
In the first and second embodiments, the example in which the vibration force generating means 3 is installed on the side opposite to the first field in the first armature which is the thrust generating surface as a linear motor has been described. Examples of the installation of the vibration force generating means 3 include those shown in FIGS. 3 (a) and 3 (b).
FIG. 3 is a front view of a permanent magnet type synchronous linear motor according to a third embodiment of the present invention as viewed from the traveling direction. FIG. 3A is a gap-facing linear motor in which an armature and a field face each other on one side. (B) is an example applied to a magnetic flux penetrating linear motor in which an armature and a field magnet face each other on both sides. As shown in FIGS. 3 (a) and 3 (b), the vibration force generating means 3 is positioned away from the opposing portion of the first field 1 and the first armature 2 and the table mounting surface 5 of the mover. It is good to install.
Since the third embodiment has the above-described configuration, the vibration force generating means 3 can be freely attached to the table of the mover according to the application, and the degree of design freedom can be increased.
[0012]
Note that the second armature winding used for the vibration force generating means in this embodiment may be a single-phase coil in which all element coils are connected in series, or divided into the same number of phases as the first armature winding. It may be a winding. In this case, the peak position of the generated electromagnetic vibration force changes by adjusting the magnitude of the DC current flowing through the armature winding for each phase. Therefore, the phase of the vibration force is adjusted electrically according to the cogging thrust. Easy to do.
In the present embodiment, the first field and the second armature are configured as a stator, and the others are configured as a mover. However, the reverse, the replacement of the first field and the second armature, etc. Free to choose.
In the present embodiment, the case where the slot shape is an open slot has been described. However, for example, a semi-open slot may be used.
[0013]
【The invention's effect】
The embodiment of the present invention has the following effects.
(1) Since the first embodiment is configured as described above, the magnitude of the cogging thrust generated between the first field and the first armature even when the cogging thrust becomes larger than the design value. By applying the combined DC current to the second armature by operating the vibration force generating means, the cogging thrust can be returned to the minimum value which is the design value.
This eliminates the need for repeated evaluation and design work when evaluating the cogging thrust of a linear motor, and easily reduces the cogging thrust even if the actual machine geometry and the actual magnetic characteristics of the magnetic member deviate from the design values. It is possible to provide a permanent magnet type synchronous linear motor that can be used.
Further, since the field generating source of the vibration force generating means is a permanent magnet, an excitation current for generating the second field is not required, so that an increase in power loss and temperature increase due to the addition of the vibration force generating means. Can be further suppressed.
Further, the configuration in which the auxiliary teeth are provided as in this example has a smaller cogging thrust than that in which the auxiliary teeth are not provided, so that less power is supplied to the vibration force generating means 3 and the vibration force generating means. It is possible to suppress an increase in power loss and temperature rise due to the addition of.
[0014]
(2) Since the second embodiment has the above-described configuration, even when the cogging thrust is larger than the design value, the magnitude of the cogging thrust generated between the first field and the first armature is reduced. By applying the combined DC current to the second armature by operating the vibration force generating means, the cogging thrust can be returned to the minimum value which is the design value.
This eliminates the need for repeated evaluation and design work when evaluating the cogging thrust of a linear motor, and easily reduces the cogging thrust even if the actual machine geometry and the actual magnetic characteristics of the magnetic member deviate from the design values. It is possible to provide a permanent magnet type synchronous linear motor that can be used.
Further, since no permanent magnet is used for the vibration force generating means, it is possible to suppress an increase in cost due to the addition of the vibration force generating means and an increase in the number of assembly steps represented by the attachment of the permanent magnet.
[0015]
(3) Since the third embodiment has the above-described configuration, the vibration force generating means can be freely attached to the table of the mover according to the application, and the degree of design freedom can be increased.
[Brief description of the drawings]
FIG. 1 is a side sectional view of a permanent magnet synchronous linear motor showing a first embodiment of the present invention.
FIG. 2 is a side sectional view of a permanent magnet type synchronous linear motor showing a second embodiment of the present invention.
FIG. 3 is a front view of a permanent magnet type synchronous linear motor having a desirable structure in the first to fourth embodiments of the present invention viewed from the traveling direction.
FIG. 4 is a side sectional view of a conventional permanent magnet type synchronous linear motor.
FIG. 5 is a diagram showing a cogging thrust waveform of a conventional permanent magnet type synchronous linear motor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 1st field 11 1st field yoke 12 Permanent magnet 2 1st armature 21 1st armature core 21a Slot 21b Main teeth 22 1st armature coil | winding 23 Auxiliary teeth 3 Vibration force generation means 31 Second field 31a Second field yoke 31b Permanent magnet 32 Second armature 32a Second armature core 32b Second armature winding 33 Comb-shaped core

Claims (4)

Arranged on the first field yoke to be opposed to the first field magnet, in which a plurality of permanent magnets are arranged in a straight line so as to alternately have different polarities, with the first field magnet interposed through a magnetic gap. With the first armature
The first armature is composed of a first armature core having a main tooth and a slot, and a first armature winding in which a coil is wound around a slot of the first armature core,
In the permanent magnet type synchronous linear motor having the other as a stator, the mover relatively moving one of the first field and the first armature,
The first armature has a vibration force having the same period as the cogging thrust so that the cogging thrust that changes with the mover moving relative to the position excluding the side facing the first field can be offset. A permanent magnet type synchronous linear motor comprising vibration force generating means for generating The vibration force generating means is configured by arranging a plurality of permanent magnets having different polarities alternately on a second field yoke provided on a surface of the first armature excluding a surface facing the first field. A second field element, and a second armature disposed opposite to the second field with a magnetic gap,
The second armature includes a slotless second armature core, and a second armature winding in which an air-core coil is wound around the second armature core,
2. The permanent magnet type synchronous linear according to claim 1, wherein a relationship of τm2 = τm1 × 1/2 is established, where τm1 is a magnetic pole pitch of the first field and τm2 is a magnetic pole pitch of the second field. motor. The vibration force generating means includes a comb-shaped core having a slot provided on a surface excluding a surface facing the first field in the first armature, and opposed to the comb-shaped core via a magnetic gap. A second armature arranged,
The second armature includes a slotless second armature core, and a second armature winding in which an air-core coil is wound around the second armature core,
When the teeth pitch of the main teeth is τs1 and the teeth pitch of the comb-shaped core is τs2, the relationship is τs1 = τs2.
2. The permanent magnet type according to claim 1, wherein the magnetic field pitch of the first field is τm1 and the magnetic pole pitch of the second armature winding is τm2, and τm2 = τm1 × 1/2. Synchronous linear motor. Auxiliary teeth are arranged at the end of the first armature core,
When the length of the auxiliary teeth in the direction perpendicular to the longitudinal direction of the first field is Hd, and the length of the main teeth in the direction perpendicular to the longitudinal direction of the first field is Ht, The permanent magnet type synchronous linear motor according to claim 1 , wherein the length of the auxiliary teeth is set in a range of 0 <Hd <Ht.

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