JP2003333823A - Voice coil type linear motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a voice coil type linear motor capable of suppressing a decrease in thrust near the end of a permanent magnet and obtaining stable thrust. <P>SOLUTION: First auxiliary permanent magnets 51 to 54 are provided between permanent magnets 41 to 48 arranged on respective yokes 1 and 2. Second auxiliary permanent magnets 61 to 64 are provided between the permanent magnets 41 to 48 arranged on the respective yokes 1, 2 and a side yoke 3. Magnetization directions of the first auxiliary permanent magnets 51 to 54 and the second auxiliary permanent magnets 61 to 68 are set so as to differ by 90° from magnetizing directions of the adjacent permanent magnets 41 to 48. Polarities of the auxiliary permanent magnets 51 to 54 and the second auxiliary permanent magnets 61 to 68 are constituted so as to have the same polarities as magnetic poles of surfaces facing spaces of the adjacent permanent magnets 41 to 48. It is preferably to set it such that 1<H/B<1.7, where B is the thickness of each permanent magnet 41 to 48, and H is the thickness of each first auxiliary permanent magnet 51 to 54 and second auxiliary permanent magnet 61 to 68. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voice coil type linear motor used for semiconductor manufacturing equipment or machine tools for vibration isolation.

[0002]

2. Description of the Related Art Conventionally, a voice coil type linear motor for vibration isolation used in a semiconductor manufacturing apparatus or a machine tool is shown in FIGS. FIG. 8 is a side sectional view of a voice coil type linear motor showing a first conventional technique. In FIG. 8, 1 is a pair of outer yokes made of parallel magnetic materials, 2 is an inner yoke provided in parallel with the outer yoke, and 3 is side yokes provided at both ends of the outer yoke 1 and the inner yoke 2. The outer yoke 1, the inner yoke 2, and the side yoke 3 form a sun-shaped closed magnetic circuit. Reference numerals 41 to 48 are a plurality of permanent magnets that form field poles provided on the surfaces of the outer yoke 1 and the inner yoke 2 that face each other. The permanent magnets 41, 43 and 42, 44 and 4
The magnetic poles of the facing surfaces of 5, 47 and 46, 47 are reversed, and the magnetic poles of the adjacent permanent magnets 41, 42, 43, 44 and 45, 46 and 47, 48 are also reversed. There is. Further, 7 is a permanent magnet 41.
The armature coils are arranged so as to face the magnetic pole surfaces of ~ 48 with a gap, and constitute an armature. The armature coil 7 moves in the longitudinal direction of the outer yoke 1 and the inner yoke 2. FIG. 9 is a side sectional view of a voice coil type linear motor showing a second conventional technique. As shown in FIG. 9, the second conventional technique is the same as the first conventional technique in that the outer yoke 1, the inner yoke 2, and the side yoke 3 constitute a closed V-shaped magnetic circuit. A pair of permanent magnets 41, 43, on the opposing surfaces of the yoke 1 and the inner yoke 2,
45 and 47 are provided between the permanent magnets 41 and 43 and 4
The difference is that the armature coils 7 are arranged between 5 and 47, respectively. The magnetic poles on the surfaces of the permanent magnets 41, 43 and 45, 47 facing each other are arranged to be reversed.

[0003]

However, in the above-mentioned prior art, the trapezoidal shape in which the magnetic flux density in the air gap is substantially evenly distributed in the central portion of each permanent magnet, and the magnetic flux density decreases at the end portions of the permanent magnets. It has a shape distribution. Therefore, when the armature coil is located in the air gap near the end of the permanent magnet, the thrust is reduced. The present invention has been made to solve the above problems, and an object of the present invention is to provide a voice coil type linear motor that suppresses a decrease in thrust near the end of a permanent magnet and can obtain stable thrust.

[0004]

In order to solve the above-mentioned problems, the invention of claim 1 provides a pair of outer yokes made of parallel magnetic bodies, and an inner yoke provided in parallel with the outer yokes. The outer yoke and the side yokes provided at both ends of the inner yoke constitute a sun-shaped closed magnetic circuit,
A plurality of permanent magnets are provided at equal pitches on the surfaces of the outer yoke and the inner yoke that face each other, and the permanent magnets have polarities of the magnets that face the outer yoke and the inner yoke, respectively, and the respective yokes. A stator is formed by reversing the polarities of the adjacent magnets arranged in, and an armature coil is arranged between the permanent magnets via a gap to form a mover, In a voice coil type linear motor in which the armature coil is moved in the axial direction between the respective yokes, a first auxiliary permanent magnet is provided between adjacent permanent magnets arranged in the respective yokes. A second auxiliary permanent magnet is provided between the permanent magnets arranged on the respective yokes and the side yokes, and the magnetization directions of the first auxiliary permanent magnet and the second auxiliary permanent magnet are Magnets of adjacent permanent magnets While in the direction 90 degrees different from the polarity of the first auxiliary permanent magnet and the second auxiliary permanent magnet is obtained by the magnetic pole and the pole of the surface facing the air gap of the adjacent permanent magnets.

According to the structure of claim 1, it is possible to suppress a decrease in the magnetic flux density in the air gap between adjacent permanent magnets provided in the outer yoke and the inner yoke, and the armature coil is provided in the outer yoke and the inner yoke. Even when it is located in the space near the provided adjacent permanent magnets, it is possible to suppress the thrust reduction.

According to a second aspect of the present invention, in the voice coil type linear motor according to the first aspect, the permanent magnet (41
.About.48) as B, and the thicknesses of the first and second auxiliary permanent magnets (51-54, 61-68) as H, 1
<H / B <1.7.

According to the second aspect of the invention, it is possible to suppress a decrease in the magnetic flux density in the air gap between the permanent magnets provided on the outer yoke and the inner yoke and the side yoke, so that the armature coil approaches the side yoke. Even if it does, the thrust reduction can be suppressed.

According to a third aspect of the present invention, a pair of outer yokes made of parallel magnetic bodies, an inner yoke provided in parallel with the outer yoke, and both end portions of the outer yoke and the inner yoke are provided. The side yoke and the side yoke form a closed letter magnetic circuit, and a plurality of permanent magnets are provided at equal pitches on the surfaces of the outer yoke and the inner yoke that face each other. A stator is configured by reversing the polarities of the magnets facing the inner yokes and the polarities of the adjacent magnets arranged on the yokes, respectively, and forming a gap between the permanent magnets. A voice coil linear motor in which armature coils are arranged via a armature coil to move the armature coils in the axial direction between the yokes. With permanent magnet and said side An auxiliary permanent magnet is provided between the magnets so that the magnetization direction of the auxiliary permanent magnet is different from the magnetization direction of the adjacent permanent magnet by 90 degrees, and the polarity of the auxiliary permanent magnet is adjacent to the adjacent permanent magnet. The magnetic pole is the same as the magnetic pole on the surface facing the void.

According to the third aspect of the present invention, it is possible to suppress a decrease in the magnetic flux density in the air gap between the permanent magnets provided on the outer and inner yokes and the side yoke, and even when the coil approaches the side yoke. Thrust reduction can be suppressed. According to a fourth aspect of the present invention, in the voice coil type linear motor according to the third aspect, when the thickness of the permanent magnet is B and the thickness of the auxiliary permanent magnet is H, 1 <H / B <1.7. It was done.

According to the structure of claim 4, it is possible to suppress a decrease in the magnetic flux density in the air gap between the permanent magnets provided in the outer yoke and the inner yoke and the side yoke, and the armature coil approaches the side yoke. Even in this case, the thrust can be prevented from decreasing.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view of a voice coil type linear motor showing a first embodiment of the present invention. It should be noted that description of the components of the present invention that are the same as those of the first conventional technique will be omitted, and only different points will be described. In the figure,
Reference numerals 51 to 54 are first auxiliary permanent magnets, and 61 to 68 are second auxiliary permanent magnets. The features of the present invention are as follows. That is, the present voice coil type linear motor is configured such that adjacent permanent magnets 41 to 4 arranged on the respective yokes 1 and 2 are adjacent to each other.
8 are provided with first auxiliary permanent magnets 51 to 54, and second auxiliary permanent magnets 61 to 64 are provided between the side yokes 3 and the permanent magnets 41 to 48 arranged on the respective yokes 1 and 2. The magnetizing directions of the first auxiliary permanent magnets 51 to 54 and the second auxiliary permanent magnets 61 to 68, which are provided, are set to be adjacent to each other.
In addition to making the magnetization direction different from 1 to 48 by 90 degrees,
The polarities of the first auxiliary permanent magnets 51 to 54 and the second auxiliary permanent magnets 61 to 68 are the same as the magnetic poles of the surfaces of the adjacent permanent magnets 41 to 48 that face the air gaps.

Next, the operation of the auxiliary permanent magnet will be described. FIG. 3 is a schematic diagram for explaining the action of the auxiliary permanent magnet in the first embodiment. In the figure, the permanent magnets 41, 43,
First auxiliary magnets 51, 52, second auxiliary magnets 61, 63
Although the portion of the above is illustrated, the operation of the first auxiliary magnets 51 and 52 will be described here. The magnetic field 83 near the center of the permanent magnets 41 and 43 is substantially parallel to the magnetic pole surface of the permanent magnet, and is a uniform magnetic field. When there is no auxiliary permanent magnet, the magnetic fields at the ends of the permanent magnets 41 and 43 are as shown in FIG.
As indicated by No. 84, the magnetic flux density decreases because it spreads to the outside. Since the magnetic field generated by the first auxiliary permanent magnets 51, 52 is 81, the magnetic field 9 combined with the magnetic field 84 is the permanent magnet 41,
It is parallel to the magnetic field at the center of 43. That is, by using the first auxiliary permanent magnets 51, 52, the permanent magnets 41,
It is possible to cancel the spread of the magnetic flux at the 43rd end and suppress the decrease in the magnetic flux density. The same effect can be obtained with the other second auxiliary magnets.

Next, the relationship between the shape of the auxiliary permanent magnet and the magnetic flux density will be described. FIG. 4 is a schematic view showing the shapes of the permanent magnet and the auxiliary permanent magnet. As shown in FIG. 4, the width of the permanent magnet is A, the thickness is B, the width of the auxiliary permanent magnet is W, and the thickness is H. Since the width A of the permanent magnet is larger than the thickness B, the magnetic flux density at the end of the permanent magnet is affected by the thickness B of the permanent magnet and the thickness H of the auxiliary permanent magnet. Therefore, regarding the relationship between the thickness B of the permanent magnet, the thickness H of the auxiliary permanent magnet, and the magnetic flux density, the gap AB between the outer yoke and the inner yoke shown in FIG.
An explanation will be given based on the magnetic flux density distribution between them. FIG. 6 is a diagram showing calculation results of magnetic field analysis of the magnetic flux density in the air gap between A and B shown in FIG. 5 by the finite element method. It can be seen that the magnetic flux density at the end of the magnet increases when H / B> 1. When H / B becomes larger than 1.7, the magnetic flux density at both ends of the magnet suddenly changes, resulting in an unfavorable distribution for obtaining a constant thrust.

FIG. 7 shows the relationship between the height of the auxiliary magnet, the ratio H / B of the permanent magnet B and the width of the region where the magnetic field is uniform in FIG. The wider the region in which the magnetic field is uniform, the wider the range in which a constant thrust force can be selected, and the lowering of the thrust force at the magnet end can be suppressed. The area of the uniform magnetic field is the length up to the position where the magnetic field increases or decreases by 3% with respect to the magnetic field at the center of the air gap, and the length at H / B = 1 is normalized to 1 and displayed. H / B> 1 increases the uniform area
It peaks near B = 1.7. When H / B> 1.7, the change at both ends of the magnet becomes sharp, so that the distribution is not preferable for obtaining a constant thrust.

In the first embodiment of the present invention, adjacent permanent magnets 41 to 4 arranged on the respective yokes 1 and 2 as described above.
8, first auxiliary permanent magnets 51 to 54 are provided, and second auxiliary permanent magnets 61 to 64 are provided between the side yokes 3 and the permanent magnets 41 to 48 arranged on the respective yokes 1 and 2. First auxiliary permanent magnets 51 to 54 and second auxiliary permanent magnet 61
.. 68 are made to differ from the magnetization directions of the adjacent permanent magnets 41 to 48 by 90 degrees, and the first auxiliary permanent magnets 51 to 54 and the second auxiliary permanent magnets 61 to 68 are made.
Of the outer yoke 1 and the inner yoke 2 because the polarities of the magnetic poles are the same as the magnetic poles of the surfaces of the adjacent permanent magnets 41 to 48 that face the air gaps.
Even when the armature coil 7 is located in the space near the adjacent permanent magnets provided in the outer yoke 1 and the inner yoke 2, it is possible to suppress the decrease in the magnetic flux density in the space near the adjacent permanent magnets provided in the. Thrust reduction can be suppressed.
Further, when the thickness of the permanent magnets 41 to 48 is B and the thicknesses of the first and second auxiliary permanent magnets 51 to 54 and 61 to 68 are H, 1 <H / B <1.7. It is possible to suppress a decrease in magnetic flux density in the air gap between the permanent magnets provided on the yoke and the inner yoke and the side yoke, and to suppress a decrease in thrust even when the armature coil approaches the side yoke. The magnetic field 82 in the yoke due to the auxiliary permanent magnets has a direction opposite to that of the magnetic field 85 of the permanent magnets and cancels each other out, so that the magnetic flux density in the outer yoke 1 becomes low. As a result, the width of the outer yoke 1 can be reduced, which has the effect of reducing the size of the device.

Next, a second embodiment of the present invention will be described. The second embodiment is different from the first embodiment in that a voice coil type linear motor is provided with a plurality of permanent magnets 41, 43, 45, 47 at equal pitches on the surfaces of the outer yoke 1 and the inner yoke 2 facing each other. The auxiliary permanent magnets 61 to 68 are provided between the permanent magnets 41, 43, 45, 47 disposed on the respective yokes 1 and 2 and the side yoke 3, and the auxiliary permanent magnets 61 to 68 are provided. The magnetizing direction of 68 is set to the adjacent permanent magnets 41, 4
The magnets 3, 45 and 47 are made to be different from each other by 90 degrees, and the polarities of the auxiliary permanent magnets 61 to 68 are the same as the magnetic poles of the surfaces of the adjacent permanent magnets 41, 43, 45 and 47 which face the air gaps. That is the point. The operation is the same as that of the first embodiment, so the description thereof will be omitted.

In the second embodiment of the present invention, the permanent magnets 41, 43, 4 arranged on the respective yokes 1, 2 as described above.
5, 47 and the auxiliary permanent magnets 61 to 68 are provided between the side yokes 3, and the magnetization directions of the auxiliary permanent magnets 61 to 68 are different from the magnetization directions of the adjacent permanent magnets 41, 43, 45 and 47 by 90 degrees. Since the polarities of the auxiliary permanent magnets 61 to 68 are the same as the magnetic poles of the surfaces of the adjacent permanent magnets 41, 43, 45, 47 facing the air gaps, the permanent magnets 41 provided in the outer yoke 1 and the inner yoke 2 are , 43, 45, 47 and the side yoke 3, it is possible to suppress the decrease in the magnetic flux density in the air gap, and it is possible to suppress the decrease in thrust even when the armature coil 7 approaches the side yoke 3. Further, when the thickness of the permanent magnet is B and the thickness of the auxiliary permanent magnet is H, 1 <H / B <1.7 is set. Therefore, between the permanent magnets provided on the outer yoke 1 and the inner yoke 2 and the side yokes and the vicinity thereof. It is possible to suppress a decrease in magnetic flux density in the air gap, and it is possible to suppress a decrease in thrust even when the armature coil 7 approaches the side yoke 3.

[0018]

As described above, the present invention has the following effects. (1) In the first embodiment, the first auxiliary permanent magnet is provided between the adjacent permanent magnets provided on the respective yokes, and the second auxiliary permanent magnet is provided between the permanent magnets and the side yokes provided on the respective yokes. Is provided, and the magnetization directions of the first auxiliary permanent magnet and the second auxiliary permanent magnet are the same as those of the adjacent permanent magnets.
Since the polarities of the first auxiliary permanent magnet and the second auxiliary permanent magnet are made the same as the magnetic poles of the surfaces facing the air gaps of the adjacent permanent magnets, the outer yoke and the inner yoke are made different from each other by 0 degree. It is possible to suppress the decrease in the magnetic flux density in the air gap between the adjacent permanent magnets provided, and suppress the thrust decrease even when the armature coil is located in the air gap near the adjacent permanent magnets provided in the outer yoke and the inner yoke. be able to.
Further, when the thickness of the permanent magnet is B and the thicknesses of the first and second auxiliary permanent magnets are H, 1 <H / B <1.7, so that the permanent magnets provided in the outer yoke and the inner yoke are It is possible to suppress a decrease in magnetic flux density in the air gap between the side yokes, and to suppress a decrease in thrust even when the armature coil approaches the side yokes.

(2) In the second embodiment, auxiliary permanent magnets are provided between the permanent magnets arranged on the respective yokes and the side yokes.
Since the magnetization direction of the auxiliary permanent magnets is different from the magnetization direction of the adjacent permanent magnets by 90 degrees and the polarity of the auxiliary permanent magnets is the same as the magnetic pole of the surface facing the air gap of the adjacent permanent magnets, the outer yoke It is possible to suppress the decrease in the magnetic flux density in the air gap between the permanent magnet provided in the inner yoke and the side yoke, and to suppress the decrease in thrust even when the armature coil approaches the side yoke. Further, when the thickness of the permanent magnet is B and the thickness of the auxiliary permanent magnet is H, 1 <H / B <1.7 is set. Therefore, the gap between the permanent magnet provided on the outer yoke and the inner yoke and the side yoke is provided. It is possible to suppress the decrease in magnetic flux density inside,
Even if the armature coil approaches the side yoke, it is possible to prevent the thrust from decreasing. As a result, a highly efficient voice coil type linear motor with less loss can be provided.

[Brief description of drawings]

FIG. 1 is a side sectional view of a voice coil type linear motor showing a first embodiment of the present invention.

FIG. 2 is a side sectional view of a voice coil type linear motor showing a second embodiment of the present invention.

FIG. 3 is a schematic diagram for explaining the action of the auxiliary permanent magnet in the first embodiment.

FIG. 4 is a schematic diagram showing the shapes of a permanent magnet and an auxiliary permanent magnet.

FIG. 5 is a schematic view showing a gap between an outer yoke and an inner yoke.

6 is a diagram showing a calculation result of magnetic field analysis of a magnetic flux density in a gap between A and B shown in FIG. 5 by a finite element method.

FIG. 7 shows the relationship between the ratio H / B of the thickness H of the auxiliary magnet and the thickness B of the permanent magnet in FIG. 6 and the width of the region where the magnetic field is uniform.

FIG. 8 is a side sectional view of a voice coil type linear motor showing a first conventional technique.

FIG. 9 is a side sectional view of a voice coil type linear motor showing a second conventional technique.

[Explanation of symbols]

1 Outer yoke 2 Inner yoke 3 side yoke 41-48 Permanent magnet 51-54 auxiliary permanent magnet (first auxiliary permanent magnet) 61 to 68 auxiliary permanent magnet (second auxiliary permanent magnet) 7 coils 81,82 Magnetic field created by auxiliary permanent magnet 83, 84, 85 Magnetic field created by permanent magnets 9 synthetic magnetic field

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5H633 BB09 BB11 GG03 HH02 HH05                       HH08 HH13 JA10                 5H641 BB10 BB14 GG03 HH02 HH09                       JA07 JA09

Claims (4)

[Claims] 1. A pair of outer yokes (1) made of parallel magnetic materials, and an inner yoke (2) provided in parallel with the outer yoke (1).
And the outer yoke (1) and the side yokes (3) provided at both ends of the inner yoke (2) constitute a sun-shaped closed magnetic circuit, and the outer yoke (1) and the inner yoke (1) A plurality of permanent magnets (41 to 48) are provided at equal pitches on the opposing surfaces of the yoke (2), and the permanent magnets (41 to 48) are provided on the outer yoke (1) and the inner yoke (2). A stator is configured by reversing the polarities of the magnets facing each other and the polarities of the adjacent magnets arranged on the yokes (1, 2), respectively, and the permanent magnets (41 to 48). An armature coil (7) is arranged between them to form a mover, and the armature coil (7) is moved in the axial direction between the yokes (1, 2). In the voice coil type linear motor, the yokes (1 and 2) are arranged on the respective yokes (1 and 2). During adjacent permanent magnets (41 to 48) the first auxiliary permanent magnet (51-5
4) is provided, and the permanent magnets (4) provided on the respective yokes (1, 2) are provided.
1 to 48) and the side yoke (3), a second auxiliary permanent magnet (61 to 64) is provided, and the first auxiliary permanent magnet (51 to 54) and the second auxiliary permanent magnet (51 to 54).
The auxiliary permanent magnets (61 to 68) of the first auxiliary permanent magnets (51 to 54) are made to have a magnetization direction different from that of the adjacent permanent magnets (41 to 48) by 90 degrees.
A voice coil linear motor characterized in that the polarities of the second auxiliary permanent magnets (61 to 68) are the same as the magnetic poles of the surfaces of the adjacent permanent magnets (41 to 48) facing the air gap. 2. The thickness of the permanent magnets (41-48) is B, and the first and second auxiliary permanent magnets (51-54, 6).
1 to 68), where H is 1 <H / B <1.7
The voice coil type linear motor according to claim 1, wherein 3. A pair of outer yokes (1) made of parallel magnetic materials, and an inner yoke (2) provided in parallel with the outer yoke (1).
And the outer yoke (1) and the side yokes (3) provided at both ends of the inner yoke (2) constitute a sun-shaped closed magnetic circuit, and the outer yoke (1) and the inner yoke (1) A plurality of permanent magnets (41, 43, 45, 47) are provided at equal pitches on the opposing surfaces of the yoke (2), and the permanent magnets (41, 43, 45, 47) are the outer yoke (1). And a stator is constructed by reversing the polarities of the magnets facing each other to the inner yoke (2) and the polarities of the adjacent magnets arranged on the yokes (1, 2). An armature coil (7) is arranged between the permanent magnets (41, 43, 45, 47) via a gap to form a mover, and the armature coil (7) is connected to each yoke ( 1,
2) A voice coil type linear motor configured to move in the axial direction between the permanent magnets (4) provided on the respective yokes (1, 2).
1, 43, 45, 47) and the side yoke (3) are provided with auxiliary permanent magnets (61 to 68), and the auxiliary permanent magnets (61 to 68) are magnetized in the direction of the adjacent permanent magnets (61 to 68). 41, 43, 45, 47) and 9
The auxiliary permanent magnet (61
The polarities of the adjacent permanent magnets (41, 43, 4).
5, 47) A voice coil type linear motor having the same pole as the magnetic pole of the surface facing the air gap. 4. The permanent magnets (41, 43, 45, 4)
4. The voice coil linear motor according to claim 3, wherein when the thickness of 7) is B and the thickness of the auxiliary permanent magnets (61 to 68) is H, 1 <H / B <1.7. .