JP2003088087A - Linear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized linear motor capable of remarkably suppressing a leakage magnetic flux out of the motor by a coil of an armature without increasing the distance between field yokes. SOLUTION: In the linear motor, the field yoke 1 (stator) is constituted by setting the moving direction A of the armature 6 (moving element) to a longitudinal direction. Two field permanent magnets 31 are aligned so that polarities are alternatively different in the longitudinal direction of the yoke 1 and disposed. The armature 6 is constituted of a first coil 41c and a second coil 41e arranged in parallel with a direction along a magnet row of the magnets 31 as the longitudinal direction. In this motor, a relation of Nc×Ic×Sc/ Gc=2×Ne×Ie×Se/Ge, wherein Nc, Ne are numbers of turns of the coils 41c and 41e, Ic, Ie are current values, Sc, Se are areas of air cores of the coils, and Gc, Ge are lengths of magnetic air gaps, is satisfied. Directions of the currents Ic and Ie of the coils are changed and energized so that a magnetic flux of the coil 41e becomes reverse to that of the coil 41c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a minute stroke linear motor suitable for applications requiring ultra-precision positioning and high thrust, such as table feed of semiconductor manufacturing equipment or machine tools, and more particularly, armature windings. The present invention relates to a configuration for reducing leakage magnetic flux from the.

[0002]

2. Description of the Related Art (First Prior Art) Conventionally, a fine stroke linear motor suitable for use in applications requiring ultra-precision positioning and high thrust, such as table feeding of semiconductor manufacturing equipment or machine tools, is shown in FIG. It has become. FIG. 8 is a linear motor showing a first conventional technique, and is a front sectional view common to second and fourth embodiments of the present invention described later. Further, FIG. 9 is an exploded perspective view of a linear motor showing a first conventional technique, in which a stator on one side and a moving element facing the stator are partially cut away for convenience. First, the first conventional technique will be described with reference to FIGS. 8 and 9. 1 is a field yoke, 2 is a side yoke, 3 is a field permanent magnet, 4 is a coil, 5 is a core metal, and 6 is an electric machine. Child,
7 is an armature mounting plate, G is the direction of the magnetic gap between the armature and the permanent magnet for the field, arrow A is the moving direction of the mover, B is the moving direction A of the mover and the direction of the magnetic gap G. The orthogonal direction, L1 is the distance between the field yokes 1. The linear motor is basically an electric machine which is arranged in two rows of opposing flat plate-like field yokes 1 and which is opposed to the field permanent magnets 3 through the magnetic gaps. The armature 6 is constituted by the armature 6, and the armature 6 is used as a mover, and the field permanent magnet 3 is used as a stator to relatively move the armature 6. Specifically, the field yoke 1 has a longitudinal direction that is a direction B orthogonal to the moving direction A of the armature 6 and the magnetic air gap direction G, and the side yokes are provided between the two rows of field yokes 1. It is fixed at 2. The permanent magnet 3 for field is
Two armatures 6 are arranged side by side at a predetermined pitch such that the polarities are alternately different along the moving direction of the armature 6. Also, the armature 6
Is a coil 4 arranged in parallel to the two field permanent magnets 3 and formed into a flat plate, and the coils 4 are formed on both surfaces of a cored bar 5 made of a non-magnetic member such as stainless steel. It is fixed by molding (not shown) or adhesive to form a coreless structure. Here, the dimensions of the coil are
The coil pitch C and the conductor width D, which are the moving direction, are determined so that the armature 6 can obtain a predetermined thrust and stroke. Then, the core metal 5 in which the coil 4 is integrated is fixed by the armature mounting plate 7. Although not shown, the armature 6 is supported by a support mechanism that is movable in the moving direction, and a linear scale and a sensor are provided on the mover and the stator to measure the relative movement position of the mover. A position detector such as a magnetic sensor including a head is attached. In such a configuration, when a direct current is supplied to the coil 4, the armature 6 linearly moves in the moving direction by a stroke due to the electromagnetic action of the current flowing in the coil 4 and the magnetic flux of the field permanent magnet 3.

(Second Prior Art) FIG. 10 is a perspective view of a linear motor according to the second prior art, in which the moving element and the stator are partially broken. In the linear motor, the field permanent magnets 30 and the armatures 60 arranged on the two rows of flat field yokes 10 facing each other are used, and the armatures 60 are used as moving elements. The configuration for relatively moving the armature 60 as the stator is the same as that of the first conventional technique. Here, L2 represents the distance between the field yokes 10. Basically, the difference from the first conventional technique is that two rows of opposing field yokes 10 are connected to each other by side yokes 20 at both ends in the longitudinal direction and at the center portion between the field yokes 10. The point is that the center yoke 70 is arranged to form a sun-shaped closed magnetic circuit. The field permanent magnet 30 includes the center yoke 7 of each field yoke 10.
One is arranged so that the polarities are aligned in the same direction on the surface facing 0. Further, the armature 60 is arranged so as to surround the center yoke 70 with a magnetic gap, and the core metal 50 and the coil 40 wound around the surface of the core metal 50 are resin-molded (not shown). And the like, and these are fixed to the armature mounting plate 70. Although not shown,
The armature 60 is supported by a support mechanism that is movable in the moving direction, and a position detector such as a magnetic sensor is attached to the mover and the stator to measure the position of relative movement of the mover. There is. In such a configuration, when a direct current is supplied to the coil 40, the armature 60 linearly moves in the moving direction by a stroke due to the electromagnetic action of the current flowing through the coil 40 and the magnetic flux of the field permanent magnet 30.

[0004]

However, in the first prior art, since the magnetic circuit serving as a closed magnetic circuit for the magnetic field generated by energizing the coil 4 is not formed, the magnetic flux generated by the armature 6 is not formed. Easily spreads to the outside, and the magnetic flux leaking to the outside of the linear motor increases. Then, after the leakage magnetic flux affects a device outside the motor, for example, a magnetic sensor (not shown), the linear motor malfunctions, resulting in a problem in precise positioning work. Further, in the second conventional technique, a magnetic circuit that constitutes a closed magnetic circuit for the magnetic field generated by energization of the coil 40 is formed, but the distance L2 between the field yokes 10 of the linear motor is the first. The distance L1 between the field yokes of the linear motor shown in the prior art is about twice the distance L1 and there is a problem that the size is increased. Further, as a measure for reducing the magnetic flux leakage of a linear motor other than the above, a permanent magnet for field and a coil provided with chamfers on the end surface are disclosed in JP-A-8-98496. Although it has the effect of reducing the leakage magnetic flux from the magnetic field, it has not been a fundamental solution for reducing the leakage magnetic field because the magnetic circuit has not been improved. The present invention has been made to solve the above problems, and can greatly suppress the magnetic flux leakage to the outside of the motor due to the armature coil without increasing the distance between the field yokes of the linear motor. The object is to provide a small linear motor.

[0005]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention according to claim 1 provides a field permanent magnet and two field permanent magnets arranged in two rows of opposing flat plate field yokes. In a linear motor in which one of the armatures arranged to face each other via a permanent magnet and a magnetic gap is a moving element that relatively moves, and the other is a stator, the field yoke is a moving direction of the moving element. In the longitudinal direction, the permanent magnets for field magnets are arranged side by side along the longitudinal direction of the field yoke so as to have different polarities alternately, and the armature is provided with the field magnets. And a first coil provided in the center of the armature and having a different size and shape from the first coil, and the first permanent coil is arranged in parallel with the longitudinal direction of the permanent magnet for use in the longitudinal direction. Consists of two second coils provided on both sides of the first coil One of the coils is obtained by constituting molded into a flat plate, the number of turns of the first coil Nc,
The current value is Ic, the coil air core area is Sc, and the magnetic gap length is G.
c, the number of turns of the second coil is Ne, the current value is Ie, the coil air-core area is Se, and the magnetic gap length is Ge.
Then, Nc × Ic × Sc / Gc = 2 × Ne × Ie
It satisfies the relationship of × Se / Ge, and the currents Ic and Ie supplied to the respective coils are switched in direction to be energized. Further, according to the present invention of claim 2, the field permanent magnets arranged in two rows of flat field yokes facing each other, and the electric machine facing the field permanent magnets with a magnetic gap therebetween. In a linear motor in which one of the moving elements is a moving element that relatively moves and the other is a stator, the field yoke has a longitudinal direction in a direction orthogonal to a moving direction of the moving element and a direction of the magnetic gap. And the permanent magnets for field magnets are arranged so as to have different polarities alternately along the longitudinal direction of the field yoke.
Two sets of magnet groups are arranged side by side so that their polarities are different from each other along the moving direction of the mover, and the armature extends along the magnet group of the field permanent magnet. Are arranged in parallel with each other in the longitudinal direction, have two different sizes and shapes from the first coil provided in the center of the armature and the first coil, and are provided on both sides of the first coil. It is configured by forming three coils, which are the second coil, into a flat plate shape, the number of turns of the first coil is Nc, the current value is Ic, the coil air-core area is Sc, and the magnetic gap length is Gc. When the number of turns of the second coil is Ne, the current value is Ie, the coil air-core area is Se, and the magnetic gap length is Ge, Nc × Ic × Sc / Gc =
The relationship of 2 × Ne × Ie × Se / Ge is satisfied, and the currents Ic and Ie supplied to the respective coils are switched in direction to be energized. According to a third aspect of the present invention, there is provided a field permanent magnet arranged on two rows of flat field yokes facing each other, and an armature facing the field permanent magnet via a magnetic gap. In a linear motor in which one of the two is a moving element that relatively moves and the other is a stator, the field yoke is configured such that the moving direction of the moving element is the longitudinal direction, and the field permanent magnet is , Three are arranged side by side along the longitudinal direction of the field yoke so that the polarities are alternately different, and the armatures are parallel to each other with the direction along the magnet array of the field permanent magnets being the longitudinal direction. The two coils having the same size and shape are arranged in a flat plate shape, and the currents Id supplied to the coils are changed in direction to be energized. According to a fourth aspect of the present invention, there is provided a field permanent magnet disposed on two rows of flat field yokes facing each other, and an armature disposed opposite to the field permanent magnet via a magnetic gap. In a linear motor having one of the movers as a relative mover and the other as a stator, the field yoke has a longitudinal direction in a direction orthogonal to the moving direction of the mover and the direction of the magnetic gap. The field permanent magnet is composed of a group of two magnets which are arranged so as to have different polarities alternately along the longitudinal direction of the field yoke. Two sets are arranged side by side so that the polarities are different from each other along the moving direction of the child, and the armatures are arranged in parallel with the direction along the magnet group of the field permanent magnets being the longitudinal direction. Formed by forming two coils with a flat shape It is those, in which so as to energize by changing the direction of the current Id of each other supplied to the each coil.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a front sectional view of a linear motor showing a first embodiment of the present invention, and FIG. 2 is an exploded perspective view of a linear motor showing the first embodiment of the present invention. For the sake of convenience, the stator on one side and the moving element facing it are partially cut away. It should be noted that components having the same components as those of the prior art will be denoted by the same reference numerals, description thereof will be omitted, and only different points will be described. The linear motor in the first embodiment has a field permanent magnet 31 and an armature 6 arranged in two rows of flat field yokes 1 facing each other.
With the armature 6 as a mover, and the permanent magnet 31 for field magnetism.
The basic configuration of moving the armature 6 relative to the stator is
This is the same as the first conventional technique, and the same applies to the second and subsequent embodiments. The difference between the present invention and the prior art is as follows. In the figure, 31 is a permanent magnet for field, 41c is a first
The coil 41e is a second coil. The field yoke 1 is
The moving direction A of the moving element is configured to be the longitudinal direction, and the two permanent magnets for field 31 are arranged side by side along the longitudinal direction of the field yoke 1 so that the polarities are alternately different. The armature 6 is arranged in parallel with the direction along the magnet array of the field permanent magnets 31 as the longitudinal direction, and the first coil 41c provided in the center of the armature 6 and the first coil 4 are provided.
1c has a different size and shape from the 1c, and the first coil 41c
It is a point that three coils, which are two second coils 41e provided on both sides of, are formed into a flat plate shape. In the above linear motor, the number of turns of the first coil 41c is Nc, the current value is Ic, the coil air core area is Sc, the magnetic gap length is Gc, and the number of turns of the second coil 41e is Ne and the current value is Is Ie, the coil air-core area is Se, and the magnetic air gap length is Ge, the magnetic flux generated by the second coil 41e is half the size of the magnetic flux generated by the first coil 41c, Nc × Ic × Sc / Gc = 2
× Ne × Ie × Se / Ge so that the magnetic flux produced by the second coil 41e is in the opposite direction to the magnetic flux produced by the first coil 41c.
The currents Ic and Ie supplied to each coil are switched in direction so as to be energized.

FIG. 2 shows the above relational expression, Nc × Ic.
As a method of satisfying × Sc / Gc = 2 × Ne × Ie × Se / Ge, the number of turns Ne of the second coil 41e is half the number of turns Nc of the first coil 41c. Using both 41c and the second coil 41e, the same stroke as the first prior art linear motor,
The following method may be used to obtain thrust. First, the coil air-core width Cc of the first coil 41c and the second coil 4
The coil air core width Ce of 1e is made equal to the coil air core width C of the coil 4 in the first conventional technique. Then, the sum of the number of turns Nc of the first coil 41c and the number of turns Ne of the second coil 41e is made equal to the number of turns N of the coil 4 in the first conventional technique, and the first coil 41c and the second coil 4 are arranged.
1e current values Ic, Ie and coil air core areas Sc, Se
Is the same as the current value I of the coil 4 and the coil air-core area S in the first conventional technique. At this time, considering that the coil width is proportional to the number of turns, the first coil 41c and the second coil 41c
In order to make the ratio of the magnetic flux generated by the coil 41e 2: 1, the conductor width Dc of the first coil 41c and the second coil 41
The coil width De of e is 2/3 and 1/3 of the conductor width D of the coil 4 in the first prior art, respectively.

Further, Nc × Ic × Sc / Gc = 2 × Ne
As another method of satisfying × Ie × Se / Ge, the current value Ie of the second coil 41e is changed to the current value Ic of the first coil 41c.
When it is set to half of the first coil 41c and the second coil 41
The following method may be used to obtain the same stroke and thrust as the linear motor of the first prior art by using both of e. First, the number of turns of the second coil 41e is set to the first coil 4
Similarly to the case of using the method of reducing the number of turns of 1c to half, the coil air core width Cc of the first coil 41c and the coil air core width Ce of the second coil 41e are set to the coil air core of the coil 4 in the first conventional technique. It is equal to the width C. Then, the number of turns Nc, N of the first coil 41c and the second coil 41e
e and the coil air core area Sc and Se are respectively the same as the number of turns N and the coil air core area S of the coil 4 in the first conventional technique, and the current value Ic of the first coil 41c and the current value of the second coil 41e are set. The sum of Ie is made equal to the current value I of the coil 4 in the first conventional technique. At this time, in order to set the ratio of the magnetic flux generated by the first coil 41c and the second coil 41e to 2: 1, the current value Ic supplied to the first coil 41c and the current value Ie of the second coil 41e are the first value. The current value I supplied to the coil 4 in the prior art is 2/3 and 1/3, respectively.

Therefore, in the first embodiment, the field yoke 1 is constructed with the moving direction A of the mover as the longitudinal direction, and the field permanent magnet 31 is arranged along the longitudinal direction of the field yoke 1. Are arranged side by side so that the polarities are alternately different, and the armatures 6 are arranged in parallel with the direction along the magnet row of the field permanent magnets 31 being the longitudinal direction, and Three coils, which are a first coil 41c provided in the center of the child 6 and two second coils 41e having different dimensions from the first coil 41c and provided on both sides of the first coil 41c, are flat plates. And the number of turns of the first coil 41c is Nc, the current value is Ic, the coil air core area is Sc, the magnetic gap length is Gc, and the number of turns of the second coil 41e is Ne, the current Value is Ie, coil air core area is Se, magnetic When the air gap length is Ge, the magnetic flux generated by the second coil 41e is set to be half the magnetic flux generated by the first coil 41c so that Nc ×
Ic × Sc / Gc = 2 × Ne × Ie × Se / Ge, so that the magnetic flux generated by the second coil 41e is opposite to the magnetic flux generated by the first coil 41c. Since the currents Ic and Ie supplied to the coils are switched in direction so as to be energized, the magnetic fields generated from the first coil 41c and the second coil 41e form a closed magnetic path in the immediate vicinity. Therefore, without increasing the distance L1 between the field yokes of the linear motor,
Magnetic flux leakage to the outside of the motor due to the coil of the armature can be significantly suppressed, and this also reduces the noise of the magnetic sensor installed outside the linear motor,
The positioning accuracy is improved and the leakage magnetic field to external devices is not required, which reduces the size of the linear motor.
Weight reduction and cost reduction are possible.

(Second Embodiment) FIG. 3 is an exploded perspective view of a linear motor according to a second embodiment of the present invention. For convenience, a stator on one side and a mover facing it are partially cut away. Is shown. The second embodiment is different from the first conventional art in the following points. In the figure, 3
2c and 32e are permanent magnets for field, 42c is the first coil,
A second coil 42e replaces the field permanent magnet 3 and the coil 4 shown in the front sectional view of FIG. The field yoke 1 has a longitudinal direction that is a direction B that is orthogonal to the moving direction A of the moving element and the magnetic air gap direction G, and the permanent magnets for magnetic field alternate along the longitudinal direction of the field yoke 1. Two magnet groups 32c and 32e, which are arranged so that the polarities are different from each other, are arranged side by side so that the polarities are different from each other along the moving direction A of the moving element. Further, the armature 6 is arranged in parallel with the direction B along the magnet groups 32c, 32e of the field permanent magnets being the longitudinal direction, and the first coil 42c provided at the center of the armature 6, Two second coils having different sizes and shapes from the first coil 42c and provided on both sides of the first coil 42c.
This is a point formed by forming three coils, which are the coil 42e, into a flat plate shape. In the linear motor, the number of turns of the first coil 42c is Nc, the current value is Ic, the coil air core area is Sc, the magnetic gap length is Gc, and the number of turns of the second coil 42e is Ne and the current value is Is Ie, the coil air-core area is Se, and the magnetic gap length is Ge, the magnetic flux generated by the second coil 42e is
N so that it is half the size of the magnetic flux created by c
c × Ic × Sc / Gc = 2 × Ne × Ie × Se / Ge so that the magnetic flux generated by the second coil 42e is opposite to the magnetic flux generated by the first coil 42c. , The currents Ic and I supplied to each coil
The direction of e is changed to energize.

FIG. 3 shows the above relational expression, Nc × Ic.
As a method of satisfying × Sc / Gc = 2 × Ne × Ie × Se / Ge, the air-core area Se of the second coil 42e is half the air-core area Sc of the first coil 4c. The following method may be used in order to obtain the same stroke and thrust as those of the first conventional linear motor by using both the first coil 42c and the second coil 42e. First, the end magnets 32 are arranged such that the polarities of the central magnet 32c adjacent to the portion of the field yoke 1 facing the second coil 42e alternate.
Place e. Then, the coil air-core width Cc of the first coil 42c and the coil air-core width Ce of the second coil 42e are made equal to the coil air-core width C of the coil 4 in the first conventional technique, and the air-core area of the first coil 42c is set. Sc and second coil 4
The sum of the air-core area Se of 2e is calculated by the first prior art coil 4
Is equal to the air core area S of the first coil 4c and the second coil 42e, and the current values Ic and Ie are the same as the number of turns N and the current value I of the coil 4 in the first prior art. To At this time, in order to set the ratio of the magnetic flux generated by the first coil 42c and the second coil 42e to 2: 1, the air-core area Sc of the first coil 42c and the air-core area Se of the second coil 42e are the first The air core area S of the coil 4 in the related art is 1/2 and 1/4, respectively.
As a result, in the first coil 42c and the second coil 42e, thrusts which are 1/2 and 1/4 of the thrusts obtained by the coil 4 in the first conventional technique are obtained, respectively, and the first coil 42c and the second coil 42e are obtained. When the thrusts obtained in step 1 are combined, the thrust is the same as that of the first conventional linear motor.

Therefore, in the second embodiment, the field yoke 1 is constructed such that the longitudinal direction is the direction B orthogonal to the moving direction A of the moving element and the magnetic air gap direction G.
The field permanent magnet is composed of three magnet groups 32c and 32e, which are arranged so as to have different polarities alternately along the longitudinal direction of the field yoke 1. Two sets are arranged side by side along the direction A so that the polarities thereof are different from each other, and the armature 6 includes the magnet group 3 of the field permanent magnets.
2c and 32e, the first coil 4 is disposed in parallel with the longitudinal direction B along the armature 6 and is provided in the center of the armature 6.
2c and three coils each having a different size and shape from the first coil 42c, and composed of two second coils 42e provided on both sides of the first coil 42c, formed into a flat plate shape, and , The number of turns of the first coil 42c is Nc,
The current value is Ic, the coil air core area is Sc, and the magnetic gap length is G.
c and the number of turns of the second coil 42e is Ne,
Current value is Ie, coil air core area is Se, magnetic air gap length is G
When e is set, Nc × Ic × Sc / Gc = 2 × Ne × I so that the magnetic flux generated by the second coil 42e is half the magnetic flux generated by the first coil 42c.
The directions of the currents Ic and Ie supplied to each coil such that the magnetic flux generated by the second coil 42e is opposite to the magnetic flux generated by the first coil 42c so as to satisfy the relationship of e × Se / Ge. Since the magnetic field generated from the first coil 42c and the second coil 42e forms a closed magnetic path in the immediate vicinity, the magnetic field between the field yokes of the linear motor is changed. Distance L1
The magnetic flux leakage from the armature coil to the outside of the motor can be greatly suppressed without increasing the size of the magnetic field.This also reduces the noise of the magnetic sensor installed outside the linear motor, improving the positioning accuracy. In addition, it is possible to reduce the size and weight of the linear motor and to reduce the cost because it is not necessary to take measures against the leakage magnetic field to the external device.

(Third Embodiment) FIG. 4 is a front sectional view of a linear motor showing a third embodiment of the present invention, and FIG. 5 is an exploded perspective view of a linear motor showing the third embodiment of the present invention. There
For the sake of convenience, the stator on one side and the moving element facing it are partially cut away. The third embodiment is different from the first conventional art in the following points. In the figure, 33 is a permanent magnet for field magnet, and 43 is a coil. The field yoke 1 is configured such that the moving direction A of the moving element is the longitudinal direction, and the three field permanent magnets 33 are arranged side by side along the longitudinal direction of the field yoke 1 so that the polarities are alternately different. The armature 6 is configured by molding two coils 43 having the same size and shape and arranged in parallel with each other so that the direction along the magnet row of the field permanent magnet 33 is the longitudinal direction. It is a point. In addition, the above-mentioned linear motor has two coils 4
In order that the magnitude of the magnetic flux generated by 3 is the same and the directions of the magnetic fluxes are opposite to each other, the current values of both of the coils 43 are made the same, and the directions of the currents Id supplied to the respective coils are changed. It is designed to be energized.

In this embodiment, in order to obtain the same stroke and thrust as the linear motor in the first prior art by using all the coil sides of the three coils 43, the following method may be used. First, the air core width Cd of the armature coil 43 is made equal to the coil air core width C of the coil 4 in the first conventional technique. Then, the sum of the number of turns Nd of the two coils 43 is made equal to the number of turns N of the coil 4 in the first conventional technique, and the current value Id of the coil 43 is set to the current value I of the coil 4 in the first conventional technique. Do the same. At this time, considering that the coil width is proportional to the number of turns, the two coils 4
The coil width Dd of 3 is 1/2 of the conductor width D of the coil 4 in the first conventional technique.

Therefore, in the third embodiment, the field yoke 1 is constructed with the moving direction A of the moving element as the longitudinal direction, and the field permanent magnet 33 is arranged in the longitudinal direction of the field yoke 1. The three armatures 6 are arranged side by side so as to have different polarities alternately, and the armatures 6 have the same size and shape arranged in parallel with the direction along the magnet row of the field permanent magnets 33 as the longitudinal direction. The two coils 43 are formed in a flat plate shape, and both of the coils 43 have the same magnitude of the magnetic flux generated by the two coils 43 and the directions of the magnetic flux are opposite to each other. Has the same current value, and the currents Id supplied to the respective coils are changed in direction so as to be energized.
Since the magnetic field generated from the
Without increasing the distance L1 between the field yokes of the linear motor, the magnetic flux leaking to the outside of the motor due to the armature coil can be significantly suppressed, and the noise of the magnetic sensor mounted outside the linear motor can be reduced. As a result, the positioning accuracy is improved, and it is possible to reduce the size, weight and cost of the linear motor by eliminating the need for a magnetic field leakage measure for external equipment.

(Fourth Embodiment) FIG. 6 is an exploded perspective view of a linear motor according to a fourth embodiment of the present invention. For convenience, a stator on one side and a moving element facing it are partially cut away. Is shown. The difference between the fourth embodiment and the first prior art is as follows. In the figure, 3
Reference numeral 4 is a field permanent magnet, and 44 is a coil, which replaces the field permanent magnet 3 and the coil 4 shown in the front sectional view of FIG. The field yoke 1 has a moving direction A of the moving element.
And a direction B orthogonal to the magnetic air gap direction G is configured as a longitudinal direction, and the field permanent magnets 34 are arranged along the longitudinal direction of the field yoke 1 so that their polarities are alternately different. Two sets of two magnet groups are arranged side by side so that the polarities are different from each other along the moving direction of the moving element, and the armature 6 is arranged in the magnet group of the field permanent magnet 34. The point is that two coils 44 having the same size and shape and arranged in parallel with the direction along the longitudinal direction are formed into a flat plate shape. Further, in the above linear motor, the current values of both the two coils 44 are made equal so that the magnitudes of the magnetic fluxes generated by the two armature coils 44 are the same and the directions of the magnetic fluxes are opposite to each other. , The currents Id supplied to the coils 44 are switched in direction so that they are energized.

In order to obtain the same stroke and thrust as the linear motor of the first prior art by using both of the two armature coils 4d, the following method may be used. First, coil 4
The air core width Cd of No. 4 is made equal to the coil air core width C of the coil 4 in the first prior art. And two coils 44
The sum of the air-core area Sd of the coil 4 is made equal to the air-core area S of the coil 4 in the first conventional technique, and the current value Id of the coil 44 is
Is the same as the current value Id of the coil 4 in the first conventional technique. As a result, each of the thrusts obtained by the coil 4 in the first prior art in the two coils 44
A thrust of / 2 each is obtained, and when the thrusts obtained by the two coils 44 are combined, the thrust becomes the same as that of the first conventional linear motor.

Therefore, in the fourth embodiment, the field yoke 1 is constructed such that the longitudinal direction is the direction B orthogonal to the moving direction A of the moving element and the magnetic gap direction G.
The field permanent magnet 34 is composed of a group of two magnets, which are arranged so as to have different polarities alternately along the longitudinal direction of the field yoke 1, and are arranged in the moving direction of the mover. The two armatures 6 are arranged side by side so that their polarities are different from each other, and the armatures 6 have the same size and shape and are arranged in parallel with the direction along the magnet group of the field permanent magnets 34 as the longitudinal direction. The coil 44 is formed into a flat plate shape,
2 so that the magnetic fluxes generated by the two armature coils 44 have the same magnitude and the directions of the magnetic fluxes are opposite to each other.
Make the current value of both coils 44 the same,
Since the currents Id supplied to the coils are changed in direction to be energized, both coils 44 have the same characteristics.
Since the magnetic field generated from the
Without increasing the distance L1 between the field yokes of the linear motor, the magnetic flux leaking to the outside of the motor due to the armature coil can be significantly suppressed, and the noise of the magnetic sensor mounted outside the linear motor can be reduced. As a result, the positioning accuracy is improved, and it is possible to reduce the size, weight and cost of the linear motor by eliminating the need for a magnetic field leakage measure for external equipment.

Next, in order to confirm the effect of reducing the leakage magnetic field by the linear motor of the present invention, verification was performed by electromagnetic field analysis. FIG. 7 is a graph of the leakage magnetic flux ratio generated by the linear motor armature, comparing each embodiment of the present invention with the prior art. From the figure, it can be seen that the leakage magnetic flux in the armature structure of the present invention is reduced to about 1/5 to 1/10 of the conventional leakage magnetic flux as compared with the armature structure shown in the first prior art. .

In the first and second embodiments of the present invention, the number of turns of the first coil is Nc, the current value is Ic, the coil air-core area is Sc, and the magnetic gap length is Gc. The number of turns is Ne, the current value is Ie, and the coil air core area is S
e, Nc × Ic × Sc, where Ge is the magnetic gap length
As a method of satisfying / Gc = 2 × Ne × Ie × Se / Ge, the number of turns Ne of the second coil is half the number of turns Nc of the first coil, and the current value Ie supplied to the second coil is A method of halving the current value Ic supplied to one coil and a method of halving the air-core area Se of the second coil with respect to the air-core area Sc of the first coil have been exemplified, but Nc × Ic ×
As long as Sc / Gc = 2 × Ne × Ie × Se / Ge is satisfied, a method in which the number of turns, the current, the air-core area, and the magnetic gap length are changed and combined may be used. Also,
In the first embodiment, a field permanent magnet may be additionally arranged at a portion of the field yoke facing the second coil so that the polarities of the adjacent permanent magnets are different from each other.
Further, in the second embodiment, the permanent magnets arranged so that the polarities of the adjacent permanent magnets are different from each other may not be provided in the portion of the field yoke facing the second coil. Further, in the present embodiment, the moving coil type having the armature as the moving element has been described as an example, but the present invention may be applied to the moving magnet type having the field magnet as the moving element.

[0021]

As described above, the present invention has the following effects. (1) In the first embodiment, the field yoke is configured such that the moving direction of the mover is the longitudinal direction, and the permanent magnets for field have different polarities alternately along the longitudinal direction of the field yoke. The two armatures are arranged side by side as described above, and the armatures are arranged in parallel with the direction of the permanent magnets for field magnets along the magnet rows as the longitudinal direction, and the first armature is provided at the center of the armature. 3 consisting of a coil and two second coils having different dimensions from the first coil and provided on both sides of the first coil
Two coils are formed in a flat plate shape, and the number of turns of the first coil is Nc, the current value is Ic, the coil air core area is Sc, the magnetic gap length is Gc, and the second coil turns. When the number is Ne, the current value is Ie, the coil air-core area is Se, and the magnetic gap length is Ge, the magnetic flux created by the second coil is half the size of the magnetic flux created by the first coil. X Ic x Sc / G
c = 2 × Ne × Ie × Se / Ge, and the magnetic flux generated by the second coil is the first
Since the currents Ic and Ie supplied to the respective coils are switched so that the magnetic flux is generated in the opposite direction to the magnetic flux generated by the coils, the magnetic fields generated by the first coil and the second coil are closed magnetic paths in the immediate vicinity. The leakage flux to the outside of the motor due to the armature coil can be significantly suppressed without increasing the distance L1 between the field yokes of the linear motor. (2) In the second embodiment, the field yoke 1
Has a longitudinal direction that is a direction B orthogonal to the moving direction A of the moving element and the magnetic air gap direction G, and the permanent magnets for field magnets have different polarities alternately along the longitudinal direction of the field yoke. The magnets, each of which is made up of three magnet groups, are arranged side by side along the moving direction of the moving element so that the polarities are different from each other. The permanent magnets are arranged in parallel with the direction B along the direction of the magnet group being the longitudinal direction, and have the first coil provided in the center of the armature and a dimension and shape different from those of the first coil, and
Three coils, which are two second coils provided on both sides of the coil, are formed into a flat plate shape, and
The number of turns of the first coil is Nc, the current value is Ic, the coil air core area is Sc, and the magnetic air gap length is Gc, and the number of turns of the second coil is Ne, the current value is Ie, and the coil air core area is Se. , Nc × Ic × Sc / Gc =, so that the magnetic flux generated by the second coil is half the magnetic flux generated by the first coil, where Ge is the magnetic gap length.
The current Ic supplied to each coil is set so that the relationship of 2 × Ne × Ie × Se / Ge is satisfied, and that the magnetic flux generated by the second coil is opposite to the magnetic flux generated by the first coil. Since the direction of Ie is changed to energize, the magnetic field generated from the first coil and the second coil becomes a closed magnetic circuit in the immediate vicinity, and the distance L1 between the field yokes of the linear motor is not increased, and the coil of the armature is not increased. (3) In the third embodiment, the magnetic flux leaking to the outside of the motor due to the magnetic field can be significantly suppressed. In the third embodiment, the field yoke is configured so that the moving direction of the moving element is the longitudinal direction. Are arranged side by side along the longitudinal direction of the field yoke so that the polarities are alternately different, and the armatures are arranged in parallel with the direction along the magnet row of the permanent magnet for field magnet being the longitudinal direction. Same size and shape The two coils are formed in a flat plate shape, and the two coils have the same magnitude of magnetic flux, and the directions of the magnetic flux are opposite to each other. Since the current values are set to be the same and the currents Id supplied to the coils are changed in direction to be energized, the magnetic fields generated from both coils are closed magnetic paths in the immediate vicinity, and the distance L1 between the field yokes of the linear motor is increased. It is possible to significantly suppress the magnetic flux leaking to the outside of the motor due to the armature coil,
(4) In the fourth embodiment, the field yoke is configured such that the direction perpendicular to the moving direction of the mover and the magnetic air gap direction is the longitudinal direction, and the field permanent magnet is the field yoke. Two sets of magnets, each of which is arranged so that the polarities are alternately different along the longitudinal direction, are arranged side by side so that the polarities are different from each other along the moving direction of the mover. The armature has a configuration in which two coils having the same size and shape and arranged in parallel with the direction along the magnet group of the field permanent magnets as the longitudinal direction are formed in a flat plate shape. The direction of the current Id supplied to each coil is made the same so that the current values of both coils are the same so that the magnitudes of the magnetic fluxes generated by the two armature coils are the same and the directions of the magnetic fluxes are opposite to each other. Since it was changed to energize, The magnetic field generated from the coil becomes a closed magnetic circuit in the immediate vicinity, and the magnetic flux leakage to the outside of the motor due to the armature coil can be significantly suppressed without increasing the distance L1 between the field yokes of the linear motor. As a result, the noise of the magnetic sensor mounted outside the linear motor is reduced in each embodiment, so that the positioning accuracy is improved and the magnetic field leakage to the external equipment is not required. And cost reduction are possible.

[Brief description of drawings]

FIG. 1 is a front sectional view of a linear motor showing a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of the linear motor showing the first embodiment of the present invention, in which a stator on one side and a moving element facing the stator are partially cut away for convenience.

FIG. 3 is an exploded perspective view of a linear motor showing a second embodiment of the present invention, in which a stator on one side and a moving element facing the stator are partially cut away for convenience sake.

FIG. 4 is a front sectional view of a linear motor showing a third embodiment of the present invention.

FIG. 5 is an exploded perspective view of a linear motor showing a third embodiment of the present invention, in which a stator on one side and a moving element facing the stator are partially cut away for convenience.

FIG. 6 is an exploded perspective view of a linear motor according to a fourth embodiment of the present invention, in which a stator on one side and a moving element facing the stator are partially cut away for convenience.

FIG. 7 is a graph of a leakage magnetic flux ratio generated by a linear motor armature comparing each embodiment of the present invention with the related art.

FIG. 8 is a linear motor showing a first conventional technique,
FIG. 7 is a front sectional view common to the second and fourth embodiments of the present invention.

FIG. 9 is an exploded perspective view of a linear motor showing a first conventional technique, in which a stator on one side and a moving element facing the stator are partially cut away for convenience sake.

FIG. 10 is a perspective view of a linear motor showing a second conventional technique, in which a moving element and a stator are partially broken.

[Explanation of symbols]

1, 10 Field yoke 2, 20 Side yoke 3, 30, 31, 32c, 32e, 33, 34 Field permanent magnets 4, 40, 43, 44 Coil 41c, 42c First coil 41e, 42e Second coil 5 , 50 core metal 6,60 armature 7,70 armature mounting plate 80 center yoke A moving direction of moving element (stroke direction) B moving direction of moving element and direction orthogonal to magnetic air gap direction C, Cd coil empty Core width Cc First coil air-core width Ce Second coil air-core width D, Dd Coil conductor width Dc First coil conductor width De Second coil conductor width G Magnetic gap direction I, Id Current direction Ic of coil Current direction of the first coil Ie Current direction of the second coil S, Sd Coil air-core area Sc First coil air-core area Se Second coil air-core area

Claims (4)

[Claims] 1. A field permanent magnet disposed on two rows of flat field yokes facing each other or an armature facing the field permanent magnet via a magnetic gap. In a linear motor in which the other is a moving element and the other is a stator, the field yoke is configured such that a moving direction of the moving element is a longitudinal direction, and the field permanent magnet is the field. Two magnets are arranged side by side along the longitudinal direction of the magnetic yoke so that the polarities are alternately different, and the armatures are arranged in parallel with the direction along the magnet row of the field permanent magnets being the longitudinal direction. And three coils including a first coil provided in the center of the armature and two second coils having different dimensions and shapes from the first coil and provided on both sides of the first coil. Is formed into a flat plate shape, and the first The number of turns of the coil is Nc, the current value is Ic, the coil air core area is Sc, and the magnetic gap length is Gc, and the number of turns of the second coil is Ne, the current value is Ie, the coil air core area is Se, When the magnetic gap length is Ge, the relationship of Nc × Ic × Sc / Gc = 2 × Ne × Ie × Se / Ge is satisfied, and the directions of the currents Ic and Ie supplied to the coils are changed. A linear motor characterized in that it is adapted to be energized. 2. One of a field permanent magnet arranged on two rows of opposing flat field yokes and an armature opposite to the field permanent magnet via a magnetic gap. In a linear motor in which the other is a moving element and the other is a stator, and the field yoke is configured such that a longitudinal direction is a direction orthogonal to a moving direction of the moving element and a direction of the magnetic gap. The field permanent magnet is composed of a group of three magnets arranged so that the polarities are alternately different along the longitudinal direction of the field yoke, and Two sets are arranged side by side so that the polarities are different from each other along the direction, and the armatures are arranged parallel to each other with the direction along the magnet group of the field permanent magnets being the longitudinal direction, and the armatures. The first coil provided at the center of the That has a size and shape, and disposed on opposite sides of the first coil 2
Three coils each consisting of one second coil are formed in a flat plate shape, the number of turns of the first coil is Nc, the current value is Ic, the coil air core area is Sc, and the magnetic gap length is Gc. When the number of turns of the second coil is Ne, the current value is Ie, the coil air core area is Se, and the magnetic gap length is Ge, Nc × Ic × Sc / Gc = 2 × Ne × Ie × A linear motor which satisfies the Se / Ge relationship and is configured such that the directions of the currents Ic and Ie supplied to the respective coils are changed so that the coils are energized. 3. One of a field permanent magnet arranged on two rows of flat field yokes facing each other, and an armature facing the field permanent magnet via a magnetic gap. In a linear motor in which the other is a moving element, and the other is a stator, the field yoke is configured such that a moving direction of the moving element is a longitudinal direction, and the field permanent magnet is the field. Three magnets are arranged side by side along the longitudinal direction of the magnetic yoke so that the polarities are alternately different, and the armatures are arranged in parallel with the direction along the magnet row of the permanent magnet for field magnet being the longitudinal direction. It is characterized in that two coils having the same size and shape are formed into a flat plate shape, and the currents Id supplied to the respective coils are switched in direction to be energized. Linear motor. 4. One of a field permanent magnet arranged in two rows of opposing field yokes and an armature opposite to the field permanent magnet via a magnetic gap. In a linear motor in which the other is a moving element and the other is a stator, and the field yoke is configured such that a longitudinal direction is a direction orthogonal to a moving direction of the moving element and a direction of the magnetic gap. The field permanent magnet is composed of a set of two magnets which are arranged so that their polarities are alternately different along the longitudinal direction of the field yoke. Two sets are arranged side by side so that the polarities are different from each other along the direction, and the armatures have the same size and shape arranged in parallel with the direction along the magnet group of the field permanent magnets being the longitudinal direction. What is formed by forming two coils into a flat plate shape There, a linear motor, wherein the is obtained so as to energize by changing the direction of the mutual current Id supplied to the coils.