JP2006081342A - Voice coil actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a voice coil actuator capable of reducing side force without changing the input quantity of magnets and the size of a motor. <P>SOLUTION: In this voice coil actuator constituted of a center yoke 1, a pair of outer yokes 2 disposed on both sides with the center yoke 1 sandwiched, magnets 3 disposed at surfaces facing the center yoke 1 and facing the outer yoke 2 respectively, a pair of edge outer yokes 4 which magnetically joint both the edges of the respective yokes 1, 2, and an armature coil 6 inserted into two pairs of magnetic gaps constituted of the magnets 3 so as to be moved freely, the facing two magnets 3, 3 are shifted from each other in a vertical and thrust generating direction and disposed in the magnetic gap so that flux density distributed in the magnetic gap may have an arbitrary angle, and the magnets 3, 3 may become a linear symmetry with regard to the center yoke 1. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to leakage magnetic flux and overheating prevention of a voice coil actuator used in an industrial apparatus such as a liquid crystal exposure apparatus, a vibration damping apparatus of a semiconductor manufacturing apparatus, and a processing machine.

As a conventional magnet arrangement of the voice coil actuator, a magnet having the same shape is arranged so as to face the magnetic gap so as to be aligned in the thrust generation direction (see, for example, Patent Documents 1 and 2).
Further, it is also known that a magnet is arranged only in one of the center yoke and the outer yoke (for example, see Patent Document 3).
Japanese Patent No. 3296530 Japanese Patent No. 3369328 JP-A-10-154721

The invention described in Patent Document 1 is a space-saving voice coil type linear motor that has good convergence of the magnetic flux flowing between the opposing magnetic poles, makes the magnetic flux flowing through the yoke uniform, and effectively works the armature reaction over the entire stroke. For this purpose, the first magnet provided on the outer yoke has a plurality of magnets of the same width with the opposite polarities reversed, and the second magnet provided on the inner yoke has the opposite polarities reversed. A plurality of magnets having the same width, the opposing ones of the first magnet and the second magnet are arranged to have different polarities, the coil is divided into a pitch equal to the pitch of the first magnet, A thrust plate made of a non-magnetic material having a flange that is bent in a direction perpendicular to the axial direction is fixed to the side surface and the axial end of the bobbin. And it is provided with a small chamfer the opposing-axial-end portion of the net and the second magnet.
Further, in the invention described in Patent Document 2, since the chamfering of the coil end is provided only on one side, there is an imbalance in the leakage magnetic flux from the end with the chamfered end of the coil end to the outer yoke and the central yoke. As a result, the electromagnetic force (side force) in the vertical direction becomes non-uniform and pitching is likely to occur. However, the leakage magnetic flux is hardly generated at the end portion, and the vertical magnetic flux distribution is made uniform. In order to provide a linear motor that does not easily occur, for this purpose, chamfering is provided at the outer end of what is arranged at both ends in the axial direction between magnets, and a bobbin of an insulating material is fitted to the inner diameter or outer diameter of the coil, A locking portion matching the coil shape is provided in the coil fitting portion of the bobbin.
In the invention described in Patent Document 3, a magnet is fixed to the outer yoke, a bobbin is inserted outside the center yoke, a coil is wound around the bobbin, and when the coil is energized, a thrust acts on the bobbin, The bonding head rotates around the bearing. In this case, the upper and lower ends of the outer yoke and the center yoke are connected by the bottom yoke and the ceiling yoke to close the magnetic circuit, thereby reducing the size of the apparatus. Efficiency is improved.

However, the present applicant has noticed that there are the following problems in common with any of the inventions described in Patent Documents 1 to 3. This will be described with reference to FIGS.
FIG. 6 is a longitudinal sectional view of a voice coil actuator of a magnet double-sided arrangement type targeted by Patent Documents 1 and 2, and FIG. In both figures, 1 is a center yoke, 2 is an outer yoke, 3 is a magnet, 4 is an end outer yoke, 5 is a bobbin, and 6 is an armature coil.
In the voice coil actuator in which the magnet 3 and the armature coil 6 are disposed at positions symmetrical with respect to the center yoke 1, when the armature coil 6 is at the magnetic center, two sets in which the armature coil 6 is inserted Since the side forces generated in the magnetic gaps are equal and the generation directions are directions to cancel each other, the side forces are offset.

However, when the armature coil 6 moves in the thrust direction and the non-thrust direction, and the armature coil 6 is linked to the leakage flux from the end of the magnet 3, the leakage flux spreads outside the magnet 3 and the armature. The magnitude and direction of the side force generated in the two sets of magnetic gaps in which the coils 6 are inserted change, and the side force remains without being canceled.
In the conventional voice coil actuator, in order to reduce the side force, it is necessary to make the size of the magnet 3 sufficiently large with respect to the armature coil 6 so that the leakage magnetic flux does not interlink with the armature coil. Therefore, there is a problem that the thickness of the center yokes 1 and 2 necessary for configuring the closed magnetic path increases, and the size of the motor increases.
The present invention has been made in view of such problems, and a first object thereof is to provide a voice coil actuator capable of reducing side force without increasing the magnet amount and the size of the motor. .

An example of cooling the armature coil of a conventional voice coil actuator will be described with reference to FIG.
In FIG. 8, the same reference numerals as those in FIG.
Reference numeral 12 denotes a cooling pipe. The cooling pipe 12 is in contact with the armature coil 6 and absorbs heat generated from the armature coil 6 by circulating a refrigerant in the cooling pipe 12 in this state.
However, such a cooling method has been sufficient for conventional low-power voice coil actuators, but it has not been able to satisfy the recent cooling requirements for high-power voice coil actuators.
In addition, although the conventional voice coil actuator can improve the motor performance by partially recovering heat, there has been a limit to the recent high performance requirement due to insufficient heat recovery.
The present invention has been made in view of such problems, and a second object thereof is to provide a voice coil actuator with higher performance by improving heat recovery efficiency.

In order to solve the above-mentioned problem, the invention according to claim 1 relates to a voice coil actuator, and includes a center yoke, a pair of outer yokes disposed on both sides so as to sandwich the center yoke, the center yoke and the outer yoke. A magnet installed on each of the surfaces facing the yoke, a pair of outer yokes that magnetically couples both ends of each yoke, and movably inserted into two sets of magnetic gaps composed of the magnets In the voice coil actuator composed of a single armature coil, the two opposing magnets are arranged so as to be shifted from each other in the vertical direction with respect to the magnetic gap, so that the magnetic flux density distributed in the magnetic gap can be arbitrarily set. It is characterized in that it is provided with an angle and the magnet is symmetric with respect to the center yoke center.
The invention according to claim 2 also relates to a voice coil actuator, and includes a center yoke, a pair of outer yokes disposed on both sides so as to sandwich the center yoke, and a surface facing the center yoke and the outer yoke. One armature inserted movably in two sets of magnetic gaps composed of the magnets, a pair of outer yokes that magnetically couples both ends of each yoke, and the magnets In a voice coil actuator composed of coils, two opposing magnets are placed perpendicular to the magnetic gap and shifted in the direction of thrust generation, so that the magnetic flux density distributed in the magnetic gap has an arbitrary angle. The magnet is installed so as to be symmetric with respect to the center yoke center.
A third aspect of the present invention relates to a voice coil actuator, and includes a center yoke, a pair of outer yokes disposed on both sides so as to sandwich the center yoke, and a surface facing the center yoke and the outer yoke. One armature inserted movably in two sets of magnetic gaps composed of the magnets, a pair of outer yokes that magnetically couples both ends of each yoke, and the magnets In the voice coil actuator composed of coils, the opposing two magnets have different sizes so that the magnetic flux density distributed in the magnetic gap has an arbitrary angle, and the magnet is the center yoke. It is characterized by being installed so as to be symmetrical at the center.
According to a fourth aspect of the present invention, in the voice coil actuator according to any one of the first to third aspects, a bobbin around which the armature coil is wound is covered with a jacket, and a joint between the bobbin and the jacket is a sealing material or The armature coil is completely sealed by an O-ring, and the armature coil is directly cooled by flowing a refrigerant between the armature coil and the jacket.
According to a fifth aspect of the present invention, in the voice coil actuator according to the fourth aspect of the invention, the O-ring has a surface arrangement.
A sixth aspect of the present invention is characterized in that a plurality of voice coil actuators according to any one of the first to fifth aspects are connected to each other in the thrust generation direction.

The present invention has the following effects.
(1) Two opposing magnets are placed perpendicular to the magnetic gap and shifted in the direction of thrust generation, and given an arbitrary angle to the magnetic flux density distributed in the magnetic gap, compared to the conventional structure, at the magnet end Therefore, the side force can be reduced without increasing the magnet amount and the size of the motor.
(2) The two opposing magnets have different sizes and have an arbitrary angle in the magnetic flux density distributed in the magnetic gap, thereby suppressing the spread of leakage magnetic flux at the magnet end compared to the conventional structure. Therefore, the side force can be reduced without increasing the magnet amount and the size of the motor.
(3) The voice coil actuator can be improved in performance by greatly improving the heat recovery amount by direct cooling of the coil.
(4) In order to ensure the sealing performance of the jacket, an O-ring is used and the arrangement is a surface, and the reliability of the sealing performance can be improved.

[Example 1]

Embodiments of the present invention will be described below with reference to FIGS.
FIG. 1 is a front view of a voice coil actuator according to a first embodiment of the present invention with reduced side force. 2 is a cross-sectional view taken along the line AA of FIG.
In FIG. 2, the same reference numerals as those in FIG.
Reference numeral 7 denotes an outer cover. The opposing magnets 3 are arranged at an arbitrary distance perpendicular to the magnetic gap and shifted in the thrust generation direction, and are arranged symmetrically with the center yoke 1 as the center.
The difference between the present invention and Patent Document 1 is that the opposing magnets 3 are placed at an arbitrary distance perpendicular to the magnetic gap and shifted in the thrust generation direction.
[Example 2]

Next, a second embodiment of the present invention will be described with reference to FIG.
FIG. 3 is a cross-sectional view of a voice coil actuator according to a second embodiment of the present invention with reduced side force.
In FIG. 3, the same reference numerals as those in FIG.
The opposing magnets 3 have different sizes and are arranged symmetrically with the center yoke 1 as the center.
The difference between the present invention and Patent Document 1 is that the size of the opposing magnet 3 is different.

Below, an example of the effect of this invention is shown based on an analysis.
FIG. 4 is a magnetic flux density distribution diagram by analysis of an example to which the present invention is applied.
FIG. 5 is a magnetic flux density distribution diagram obtained by analyzing a case where a conventional structure is applied.
In both figures, the same reference numerals as those in FIG.
In FIG. 4, the leakage magnetic flux from the end of the magnet 3 interlinking with the armature coil 6 is suppressed from spreading outward compared to the leakage magnetic flux from the end of the magnet 3 interlinking with the armature coil 6 in FIG. I know that. For this reason, the side force is reduced in the present invention.
4 and 5, the coordinates of the magnetic center are (X, Y) = (0 mm, 0 mm), and a certain point on the armature coil in the figure is a position where the coordinates (X, Y) = (3 mm, 2 mm). , The armature coil is energized for 3000 ampere turns, and the side force against the generated thrust at that position is 3.06% in the present invention as shown in the lowest stage of Table 1, and 2.3 in the conventional structure. 44%.

ところが、その位置から電機子コイルをＹ方向にのみ１ｍｍ相対移動させ、Ｘ方向は２ｍｍでそのままとしたと移動させた場合（（Ｘ，Ｙ）＝（３ｍｍ,１ｍｍ）のサイドフォースは本発明では１．３５％、従来構造では１．７７％である。
さらに、その位置から電機子コイルをＹ方向にのみ１ｍｍ相対移動させ、Ｘ方向は２ｍｍでそのままとしたと移動させた場合場合（（Ｘ，Ｙ）＝（３ｍｍ,０ｍｍ）のサイドフォースは本発明では０．３１％、従来構造では０．３８％である。
このように、表１によると、本発明のものが従来構造に比べサイドフォースが低減されていることがよく判る。
［実施例３］

However, when the armature coil is moved relative to the Y direction only by 1 mm from that position and moved in the X direction as it is at 2 mm ((X, Y) = (3 mm, 1 mm)), the side force is 1.35% and 1.77% for the conventional structure.
Further, when the armature coil is moved relative to the Y direction only by 1 mm from that position and moved in the X direction as it is at 2 mm ((X, Y) = (3 mm, 0 mm)), the side force is the present invention. Is 0.31%, and the conventional structure is 0.38%.
Thus, according to Table 1, it can be seen that the side force of the present invention is reduced compared to the conventional structure.
[Example 3]

Further, a third embodiment of the present invention will be described with reference to FIG.
In FIG. 8, the same reference numerals as those in FIG.
FIG. 8 is a cross-sectional view of the voice coil actuator according to the third embodiment, and is an example in which the magnet 3 is disposed on the stator. However, the present invention is not limited to this, and the reverse (that is, the stator is an electric machine). (Child coil). Reference numeral 8 denotes a jacket configured to directly cool the armature coil 6. The bobbin 5 and the jacket 8 are made of a nonmagnetic material such as engineering plastic or ceramics so that eddy currents are not generated. Reference numeral 10 denotes a gap formed between the jacket 8 and the armature coil 6 and serves as a refrigerant passage. Reference numeral 9 denotes an O-ring that ensures the sealing performance of the jacket. In this case, the O-ring 9 may be a sealing material. Reference numeral 11 denotes a seal groove. FIG. 9 shows a state in which the armature coil 6, the bobbin 5, and the jacket 8 become one unit. This unit is fastened to the stator side with bolts not shown in FIG.
The voice coil actuator according to the third embodiment of the present invention is different from that of the prior art shown in FIG. 11 in that the prior art makes the cooling pipe 12 contact the armature coil 6 (FIG. 11), and the inside of the cooling pipe 12 is changed. Whereas heat is indirectly recovered by circulating refrigerant, in the third embodiment of the present invention, the armature coil 6 (FIG. 9) is covered with the jacket 8 and the armature coil 6 is directly circulated and cooled by the refrigerant. It is a point to do. In addition, since the injection port and extraction port of a refrigerant | coolant are possible by diversion of a well-known technique, it abbreviate | omits from explanatory drawing.
Note that the voice coil actuator according to the third embodiment of the present invention is arranged with a gap serving as the refrigerant passage 10, which causes a decrease in characteristics due to the enlargement of the magnetic gap, but the heat recovery effect by direct cooling is more conspicuous. large.
As described above, the armature coil 6 is covered with the jacket 8 and directly cooled with the refrigerant, so that the cooling efficiency is remarkably improved, and it is possible to contribute to higher output (in other words, lower heat generation) of the voice coil actuator. It became.
[Example 4]

FIG. 10 is a diagram for explaining a coil unit according to a fourth embodiment of the present invention, in which (a) is a longitudinal sectional view (b) is a perspective view. The coil unit according to the fourth embodiment is basically the same as the configuration of FIG. 9, but is characterized in that the O-ring 9 that affects the sealing performance is arranged in a plane.
In FIG. 10, the O-ring 9 is arranged in a circumferential shape, and the sealing performance greatly depends on the fitting state of the bobbin 5 and the jacket 8. If the bobbin 5 and the armature coil 6 are cylindrical, it is relatively easy to manage the size of the fitting, but the rectangular cylinder shown in the figure is very difficult. As shown in FIG. 10, the shapes of the bobbin 5 and the jacket 8 are reviewed, and seal grooves 11 are circumferentially arranged on the upper and lower surfaces, respectively, and an O-ring 9 is embedded in the seal grooves 11 (however, in the figure, the seals on the lower surface are sealed). The O-ring 9 is embedded in the groove 11 and the O-ring 9 is not yet embedded in the seal groove 11 on the upper surface.), So that it is not affected by the fitting state of the bobbin 5 and the jacket 8 It was. That is, by providing the O-ring 9 as a surface arrangement, it is possible to secure stable sealing performance and improve reliability.

  As described above, according to the present invention, by directly cooling the coil, the voice coil actuator can be improved in performance, increased in output, and reduced in size, and accordingly, in industries such as semiconductor-related devices, mounting machines, and processing machines. It can contribute to high performance and downsizing of machines.

It is a front view of the voice coil actuator which shows 1st Example of this invention. It is sectional drawing of the voice coil actuator which shows 1st Example of this invention. It is sectional drawing of the voice coil actuator which shows 2nd Example of this invention. It is a magnetic flux density distribution map by the analysis of the magnet edge part in this invention structure. It is a magnetic flux density distribution figure by the analysis of the magnet edge part in a conventional structure. It is sectional drawing of the voice coil actuator example 1 of a conventional structure. It is sectional drawing of the voice coil actuator example 2 of a conventional structure. It is sectional drawing of the voice coil actuator which shows 3rd Example of this invention. It is a fragmentary sectional view which shows the coil unit of the voice coil actuator of this invention. It is a figure which shows the coil unit of 4th Example, (a) is a fragmentary sectional view, (b) is a perspective view. It is sectional drawing which shows the conventional voice coil actuator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Center yoke 2 Outer yoke 3 Magnet 4 End part outer yoke 5 Bobbin 6 Armature coil 7 Outer cover 8 Jacket 9 O ring 10 Refrigerant flow path 11 Seal groove 12 Cooling pipe

Claims (6)

A center yoke, a pair of outer yokes arranged on both sides so as to sandwich the center yoke, magnets installed on the surfaces facing the center yoke and the outer yoke, and both ends of each yoke are magnetized. A voice coil actuator composed of a pair of outer yokes coupled to each other and one armature coil movably inserted into two sets of magnetic gaps composed of the magnets;
By arranging the two opposing magnets to be shifted from each other in the vertical direction in the magnetic gap, the magnetic flux density distributed in the magnetic gap is given an arbitrary angle, and the magnet is symmetric about the center yoke center. The voice coil actuator is characterized by being installed as follows. A center yoke, a pair of outer yokes arranged on both sides so as to sandwich the center yoke, magnets installed on the surfaces facing the center yoke and the outer yoke, and both ends of each yoke are magnetized. A voice coil actuator composed of a pair of outer yokes coupled to each other and one armature coil movably inserted into two sets of magnetic gaps composed of the magnets;
The two opposing magnets are installed perpendicular to the magnetic gap and shifted in the direction of thrust generation, so that the magnetic flux density distributed in the magnetic gap has an arbitrary angle, and the magnet is centered on the center yoke. A voice coil actuator that is installed symmetrically. A center yoke, a pair of outer yokes arranged on both sides so as to sandwich the center yoke, magnets installed on the surfaces facing the center yoke and the outer yoke, and both ends of each yoke are magnetized. A voice coil actuator composed of a pair of outer yokes coupled to each other and one armature coil movably inserted into two sets of magnetic gaps composed of the magnets;
By setting the two opposing magnets to have different sizes, the magnetic flux density distributed in the magnetic gap is given an arbitrary angle, and the magnets are installed so as to be symmetrical about the center yoke. Voice coil actuator characterized by   The bobbin around which the armature coil is wound is covered with a jacket, the joint between the bobbin and the jacket is sealed with a sealing material or an O-ring, and a coolant is passed between the armature coil and the jacket so that the armature coil is The voice coil actuator according to any one of claims 1 to 3, wherein the voice coil actuator is directly cooled.   The voice coil actuator according to claim 4, wherein the O-ring has a surface arrangement.   A voice coil actuator comprising a plurality of the voice coil actuators according to any one of claims 1 to 5 coupled together in a thrust generation direction.

Images