JP2002120120A - Moving state correcting method of table of magnetic bearing linear stage, and magnetic bearing linear stage and processing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide highly accurate progressiveness of a table without depending on accuracy of machining and setting of a guide. SOLUTION: This machine comprises a straight-driven, table 2, a linear guide 1 for guiding the movement during straight driving of the table 2 along a setting route A, and a magnetic bearing 9 for supporting the table 2 guided to the guide 1 without contacting with the guide 1. The magnetic bearing 9 is in active model having an adjusting characteristic of attitude or vibration for the guide 1 of the table 2, a moving state required of the attitude or vibration of the table 2 in the setting route A is detected from the outside, and the adjusting characteristic of the magnetic bearing 9 is controlled based on data related to the detection to correct the moving state required of the table 2 in the setting route A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of correcting a moving state of a table of a magnetic bearing linear stage, a magnetic bearing linear stage and a processing machine using the same, for example, an ultra-precision linear used for a high-precision machine tool or the like. Applied to stage and ultra-precision processing machine using it.

[0002]

2. Description of the Related Art Conventionally, an ultra-precision linear stage of this type has a hydrostatic bearing or a rolling bearing between a linear guide and a linear guide for supporting and guiding a table driven linearly with low load and high accuracy. Is widely used. FIG. 11 shows a conventional example of a hydrostatic bearing. This is a linear guide a
And a table b surrounding the table a from the three sides, an oil pocket c is provided in each part surrounding the guide a on the table b side to supply the oil, and the supplied oil has a slight gap. Then, the oil flows out to the outside, and the oil pocket c is maintained at a predetermined pressure, and the table b is floated and supported with respect to the guide a.

On the other hand, it has been proposed to use a magnetic bearing for supporting a table in a non-contact manner with a guide by a magnetic action.

[0004]

By the way, in each of the above-mentioned conventional bearings, the main purpose is to reduce the moving load of the table b, and the table b can be moved to a predetermined posture and position with high accuracy along a set path. Maintaining and moving is left solely to the processing accuracy of the guide a. For this reason, the guide a needs to be processed with an accuracy corresponding to the accuracy of the processing machine, and is subjected to ultra-precision processing for an ultra-precision processing machine. Be faster.

[0005] Further, even if the table b is guided using the guide a finished with the required accuracy and ultra-precision machining is performed, the required accuracy may not be obtained sometimes or relatively early. This is a particular problem in an ultra-precision linear stage, but it is required to increase the straightness of the table b when moving, in other words, the straightness of the moving path. Probably due to dissatisfaction.

Specifically, the guide a also needs to be machined with a straightness required for the moving path of the table b. However, even if the surface finishing accuracy and the cross-sectional dimensional accuracy can be obtained stably, The longer the guide a becomes, the more the problem of bending and inclination occurs, and it becomes difficult to process the guide a with a satisfactory straightness. In addition, although it is most important that the guide maintain its accuracy in the environment in which it is actually used, the guide may be bent over time and may be bent early depending on the weight of the object placed on the table b. The table b is easily inclined, and the initial accuracy of the table b cannot be maintained. It is conceivable.

In view of the above problems, an object of the present invention is to provide a linear stage of a magnetic bearing linear stage that can obtain a high-precision linearity on a moving path of a table without being affected by the accuracy of machining and installation of a guide. An object of the present invention is to provide a table moving state correction method, a magnetic bearing linear stage and a processing machine using the same.

[0008]

In order to achieve the above object, a method for correcting the moving state of a table of a magnetic bearing linear stage according to the present invention comprises: a table driven linearly; In a method of correcting the moving state of a table of a linear stage of a magnetic bearing linear stage, comprising: a linear guide for guiding along the guide; and a magnetic bearing for supporting a table guided by the guide without contacting the guide. Using an active type magnetic bearing that has the characteristic of adjusting the attitude or runout of the table relative to the guide, the required movement state of the attitude and runout of the table in the set path is detected from the outside, and based on the data related to the detection. In this case, the adjustment characteristics of the magnetic bearing are controlled to correct the required moving state of the table on the set path.

In such a configuration, the table is supported and guided by the magnetic bearing in a non-contact manner with respect to the guide, and is moved along the guide by linear drive. Depending on the amount, the table may swing out of the set path, the posture may be inclined along a curve in the longitudinal direction, or the posture may be inclined along the inclination around the cross section of the guide. Further, due to the imbalance of the magnetic action of the magnetic bearing, rotation around any axis other than the straight running direction and axial runout may occur.

[0010] However, among such moving states of the table, those which need to be regulated are detected from outside without affecting the operation of the table, and based on data relating to this detection, the attitude or swing of the table with respect to the guide in the magnetic bearing. By adjusting the adjustment characteristics of the table, the required movement state of the table attitude and runout on the set path is corrected, so that the table can be moved along the set path without being affected by the accuracy of the processing and installation of the guide. It can move straight ahead with precision.

As a magnetic bearing linear stage for correcting the moving state of the table, a table driven linearly and a linear guide for guiding the movement of the table during the linear driving along a set path are provided. , A magnetic bearing that supports a table guided by the guide without contact with the guide,
The magnetic bearing is an active type magnetic bearing with adjustment characteristics of attitude or runout with respect to the table guide,
Detecting means for externally detecting a required movement state of the table attitude and deflection on the set path, and controlling the adjustment characteristics of the magnetic bearing based on the detection data from the detecting means to perform necessary movement of the table on the set path A magnetic bearing control means for correcting the state is sufficient, and it is possible to automatically and stably and surely correct the necessary moving state of the table which is moved in accordance with the linear drive of the table. it can.

The detecting means includes a light projecting means for projecting light in a predetermined direction from a predetermined position outside the moving table, and a light receiving means for receiving light from the light projecting means at a predetermined position on the moving table. A light receiving means for receiving light at a predetermined position outside the moving table via an optical member at a predetermined position on the moving table, and a setting path of the moving table by comparing a light receiving condition of the light receiving means with a reference condition And determination means for determining a necessary movement state in the above.

In such a configuration, a light receiving condition that the light projecting means on the moving table receives light projected from the predetermined position outside the moving table in a predetermined direction at the predetermined position, or The light receiving condition at which the light receiving means outside the table moving through the optical member at the predetermined position on the moving table receives light at the predetermined position, the posture on the set path at each time when the table is actually moving, By giving a correlation to the required moving state of the shake, the reference light receiving condition when the necessary moving state of the table is appropriate is known, so the light receiving actually detected based on this reference light receiving condition Based on the conditions, the necessary movement state of the table on the set route at each time can be determined and detected automatically and accurately by the determination means at high speed.

If the light projecting means projects the light so as to go straight in parallel with the set path, the light receiving conditions for the optical members and the light receiving means on the table are fixed as long as the moving state on the set path of the table is appropriate. Simplifies the correlation and makes it possible to easily and quickly detect the required moving state of the table at any one time. It is suitable.

The light receiving means receives two sets of two light receivers which receive the same projected light one after another on the table surface, and two sets of light beams in the direction orthogonal to the set path on the table surface.
If two light receivers that individually receive light at two positions are used in combination, in a set of two light receivers that receive the same projection light one after another, the actual light reception relative to their reference light reception points When the point shift is opposite to each other in the vertical direction perpendicular to the table surface, the inclination in the front-rear direction is reversed. Since the tables are in the same direction, it is possible to detect the swing of the table in that direction. In the set of two light receivers in the left and right directions, the deviation of the actual light receiving point from the reference light receiving point is determined on the table surface. Since the table is vertically opposite to each other, the inclination of the table in the left and right direction can be detected. Shake in the horizontal direction of the table by the deviation of the actual receiving point with respect to the reference light receiving point of the al are identical to each other, the deflection of the perpendicular vertical direction on the table surface can be detected, respectively.

When the light receiving means uses a combination of a light receiving device for receiving the reflected light from the optical member on the table and a light receiving device for receiving the projected light transmitted through the optical member, for the same projection light. The actual light receiving point of the receiver receiving the reflected light does not deviate from the reference light receiving point of the receiver, and the actual light receiving point of the receiver receiving the transmitted light deviates from the reference light receiving point. Deflection in the direction, deviation of the actual light receiving point from the reference light receiving point of the light receiving device that receives the reflected light,
The rotation around the axis perpendicular to the table surface and the inclination before and after in the rectilinear direction are detected according to the relationship between the actual light receiving point and the reference light receiving point of the light receiving device that receives the transmitted light opposite thereto. be able to.

One light interferometer is used in which the light receiving means receives two parallel projection lights in the same reflection path through two optical members in a direction orthogonal to the set path on the table in an interference state. In the case where there is a movement of the table accompanying the parallel movement of the reflection surface of the optical member, that is, a movement other than the shake and the tilt of the table in the front-rear direction, two parallel projection lights are received through each optical member. Since the state of incidence on the means changes, many displacements of the table can be detected by one light receiving means.

A processing machine according to the present invention is a processing machine for processing a work by a tool with a relative movement of the tool and the work moving straight, wherein the magnetic bearing in each of the above cases is mounted on a tool table or a work table which is driven linearly. It is characterized by having a linear stage.

With such a configuration, the moving state of the table, which is received by the linear guide through the magnetic bearing through the non-contact guide, that is, the attitude and swing of the set path are detected, and the table is guided based on the detection result. Since it is made to move in a predetermined posture along the set route without affecting the accuracy of processing and installation, etc., ultra-high precision processing can be performed.

Further features of the present invention will become apparent from the following detailed description and drawings. Each feature of the present invention can be used alone or in combination in various combinations as much as possible.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for correcting a moving state of a table of a magnetic bearing linear stage according to an embodiment of the present invention,
A magnetic bearing linear stage and a processing machine using the same will be described with reference to FIGS. 1 to 10 to provide an understanding of the present invention.

As shown in FIGS. 1 to 9, the method of correcting the moving state of the table of the magnetic bearing linear stage according to the present embodiment includes: a table 2 driven linearly;
A linear guide 1 for guiding the movement of the linear driving device along the set path A, a magnetic bearing 9 for supporting the table 2 guided by the guide 1 without contact with the guide 1,
The magnetic bearing 9 is of an active type having a characteristic of adjusting the posture or runout of the table 2 with respect to the guide 1. At the same time, a movement state of the table 2 in the setting path A, which needs to be restricted among the posture and the deflection of the table 2, is detected from the outside, and the adjustment characteristics of the magnetic bearing 9 are controlled based on the detection data. Correct the required moving state. Here, the attitude means the rotation or inclination of the table 2 in all directions with respect to the set path A, and the shake means the parallel movement of the table 2 from the set path A. More specifically, the rotation or tilt is caused by yawing that occurs around the Z axis on the XY plane, a cross section of the guide 1, that is, rolling that occurs around the X axis on the ZY plane, or ZY.
Pitching and runout occurring around the Y axis on the surface occur in the Z axis direction and the Y axis direction. Since the X-axis direction is the moving direction of the table 2, the moving position is to be controlled.

The magnetic bearing 9 usually has the table 2 and the guide 1
Is designed so as to keep a predetermined gap with the guide surface 1a. As a result, the table 2 is supported in a non-contact state with a predetermined gap maintained by the magnetic action of the magnetic bearing 9 with respect to the guide 1, and is moved along the guide 1 by linear driving. For this reason, if there is a deviation in the straightness of the guide 1, the table 2 swings from the set path A according to the direction and amount of the deviation, or the posture is tilted along the longitudinal bend,
The posture is inclined along the inclination around the cross section of the guide 1. For some reason, such as an imbalance in the magnetic action of the magnetic bearing 9, a run-out or a tilt may also occur.

However, among such moving states, those requiring regulation are detected from outside without affecting the operation of the table 2 as described above, and the table 2 for the guide 1 in the magnetic bearing 9 is detected based on the data relating to this detection. Of the table 2 in the set path A and correct the necessary movement state of the table 2 in the set path A, so that the table 2 can be moved without being affected by the accuracy of the processing and installation of the guide 1. It is possible to move straight along the set route A with necessary accuracy. Similar adjustments are automatically made for the inclination and runout of the table 2 that occur regardless of the accuracy of the guide 1.

The active type magnetic bearing 9 as described above
5A and 5B, a plurality of electromagnets 9a1 to 9a6 and 9b1 to 9b6 are provided on a portion of the table 2 facing the guide surface 1a of the guide 1 as a representative example. And the guide 1. The set of electromagnets 9a1 to 9a6 and the set of electromagnets 9b1 to 9b6 are located before and after in the straight direction of the table 2 and in the X direction as shown in FIG.
6, each of the electromagnets 9b1 to 9b6 around the cross section of the guide 1, around the set path A, as shown in FIG.
It is arranged symmetrically up and down and left and right around the X axis. The plurality of electromagnets 9a1 to 9a6, 9b1 to 9b6 are the guide 1
A non-contact support that exerts a magnetic attraction action between the guide 1 and the guide 1 and the table 2 as described above due to the balance of the magnetic attraction force between the guides 1 facing each other. You can make a state.

However, in such a balanced state, of the plurality of electromagnets 9a1 to 9a6, 9b1 to 9b6, for example, the electromagnets 9a2 and 9b shown in FIGS.
When the attraction force of b1 is higher than the electromagnets 9a1 and 9b2,
An unbalanced force for rotating the table 2 in the direction of the arrow B around the Z axis with respect to the guide 1 is generated by the amount of the suction force, and the table 2 is moved in the direction of the arrow B according to the magnitude of the force.
Can be guided in a straight line by changing the support posture in the direction of. Also, the attraction force of the electromagnets 9a1 and 9b2 is
If it is higher than a2 and 9b1, a force for rotating the table 2 in the direction of arrow C around the Z axis is generated,
According to the magnitude of the force, the support posture of the table 2 can be changed in the direction of arrow C to guide the straight movement.

When the attraction force of the electromagnets 9a1 and 9b1 is higher than that of the electromagnets 9a2 and 9b2, an unbalanced force for moving the table 2 with respect to the set path A in the direction of arrow D on the Y axis is generated. Table 2 according to the size of
Can be translated with respect to the setting path A in the direction of arrow D, that is, can be shaken. When the attraction force of the electromagnets 9a2 and 9b2 is higher than that of the electromagnets 9a1 and 9b2, an unbalanced force that moves the table 2 in the direction of the arrow E on the Y-axis with respect to the setting path A occurs, and the force depends on the magnitude of the force. Thus, the table 2 can be swung in the direction of the arrow E with respect to the set path A.

In FIG. 5B, the electromagnets 9a3 and 9b
The attractive force of 3, 9a6, 9b6 is applied to electromagnets 9a4, 9b4,
If it is higher than 9a5 and 9b5, the table 2
An unbalanced force occurs in the direction of arrow F around the cross section, around the set path A, and around the X axis, and the table 2 can be rotated or tilted in the direction of arrow F according to the magnitude of this force. Electromagnets 9a4, 9b4, 9a5, 9
The attractive force of b5 is applied to the electromagnets 9a3, 9b3, 9a6, 9b6.
If it is higher than that, the table 2 is rotated or tilted in the direction of arrow G around the cross section of the guide 1, around the set path A, and around the X axis, and the table 2 is moved in the direction of arrow G according to the magnitude of this force. Can be tilted. Also, if the attraction force of the electromagnets 9a3, 9b3, 9a5, 9b5 is increased more than usual, an unbalanced force is generated to move the table 2 down in the H direction on the Z axis, and the table 2 is moved in accordance with the magnitude of the force. It can be moved down in the direction of arrow H. If the attraction force of the electromagnets 9a4, 9b4, 9a6, 9b6 is increased more than usual, an unbalanced force is generated to move the table 2 upward in the I direction on the Z axis, and the table 2 is moved by the arrow I according to the magnitude of the force. Can be moved upwards. Further, when the attraction force of the electromagnets 9a3, 9a5, 9b4, 9b6 is higher than that of the electromagnets 9b3, 9b5, 9a4, 9a6, an unbalanced force is generated to rotate or tilt the table 2 in the direction of arrow J around the Y axis. The table 2 can be tilted in the J direction according to the magnitude of the force. Electromagnet 9b
The attractive force of 3, 9b5, 9a4, 9a6 is applied to the electromagnet 9a3,
If it is higher than 9a5, 9b4, 9b6, an unbalanced force for rotating the table 2 in the direction of arrow K around the Y axis is generated, and the table 2 can be tilted in the K direction according to the magnitude of this force.

As a result, the table 2 is rotated or tilted around each of the X, Y, and Z axes by controlling the adjustment characteristics of the magnetic bearing 9, and other than the longitudinal direction of the guide 1 and the X direction other than the X direction coinciding with the set path A. It can be translated in both YZ directions, that is, shaken.

The inclination and / or sway of the setting route A of the table 2 which needs to be regulated can be detected by various detecting means 21 to 23 in some embodiments illustrated in FIGS. 1 and 5 based on the detection results
The energization of each of the electromagnets 9a1 to 9a6 and 9b1 to 9b6 of the magnetic bearing 9 by the magnetic bearing control means 4 shown in FIG. 9 can be individually controlled as shown in FIG. To control what is needed. This makes it possible to automatically, stably and surely correct a moving state that requires the regulation of the table 2 that is moved in conjunction with the straight drive of the table 2.

The table 2 is driven linearly by a ball screw system.
What is necessary is just to employ | adopt what is suitable for a use, such as a wire drive system, a push-movement system, and a linear motor system, and does not ask a drive system especially. However, if the linear motor system is used, a linear motor is constituted by the guide 1 and the table 2, and the same control can be conveniently performed even if the same gap adjustment is performed between the two magnets. By being between the magnets, it is not limited to the adjustment of the attraction force, but may be by adjusting the repulsion force,
Both adjustment methods can be used in combination.

The detecting means 21 illustrated in FIGS. 1 to 4 is used to detect the light 6 from a predetermined position outside the moving table 2 in a predetermined direction.
A light projecting means 31 for projecting light, a light receiving means 32 for receiving light 6 from the light projecting means 31 at a predetermined position on the moving table 2, and a light receiving condition of the light receiving means 32 are compared with a reference condition. Path A of table 2 moving
And a determining means 8 for determining a necessary moving state. Here, a light receiving condition in which the light projecting unit 31 on the moving table 2 receives light 6 projected from the predetermined position outside the moving table 2 in a predetermined direction at a predetermined position, 2 can be correlated with the required movement state of the posture and the shake on the set path A at the time when the movement of the table 2 is actually performed.
The reference light receiving condition such as the reference light receiving point O shown in FIG. 3 when the necessary moving state is appropriate is known. Also, it can be set as such. Therefore, based on the light receiving condition actually detected based on the reference light receiving condition, the necessary moving state of the table 2 in the set path A at each time is determined by the determining means 8.
Thus, it is possible to automatically and accurately determine and detect at high speed.

The light projecting means 31 projects the light 6 so as to travel straight in parallel with the set path A. As a result, the light receiving condition for the light receiving means 32 on the table 2 is fixed as long as the moving state on the setting route A of the table 2 is appropriate, that is, as long as there is no tilt or shake, the correlation is simplified and the table 2 It is possible to easily and quickly detect the necessary moving state of the vehicle. Therefore, it is suitable for controlling the required moving state of the table 2 in real time and with high responsiveness at high speed.

Further, the light receiving means 32 receives the same light 6 successively on the surface of the table 2 by a PSD (Position).
direction in which two sets of two light receivers 5a and 5b or a set of light receivers 5c and 5d, which are position detectors such as an ion sensitive device, and two parallel lights 6 are orthogonal to the setting path A on the surface of the table 2. And a combination of two photodetectors 5a and 5c or a pair of 5b and 5d that individually receive light at the two positions.

As a result, a set of two light receivers 5a and 5b or a set of light receivers 5c and 5d, which receive the same light 6 one after another and are arranged in the front-rear direction and the X direction, are shown in FIG. The deviation of the actual light receiving point O1 from the reference light receiving point O shown in FIG. 4 is opposite to each other in the Z direction perpendicular to the table surface 2a. A certain X-direction tilt, ie Y
The rotation about the axis is opposite to each other in the Y direction perpendicular to the direction in which the table surface 2a moves straight, so that the table surface 2a
The rotation about the Z-axis perpendicular to the table surface 2a and the swing of the table 2 in the same direction in the Y direction perpendicular to the rectilinear direction of the table surface 2a can be detected. Two light receivers 5 in the Y direction
a, 5c or a set of photodetectors 5b, 5d,
Since the shift of the actual light receiving point O1 with respect to the reference light receiving point O is opposite to each other in the Z direction, the inclination of the table 2 in the Y direction, that is, rotation about the X axis can be detected. At least three of the set of light receivers 5a, 5b and 5c, 5d in the direction and the set of light receivers 5a, 5c and 5b, 5d in the Y direction actually receive light relative to the reference light receiving point O. Since the shakes of the points O1 are the same as each other, it is possible to detect the left-right shake in the Y direction and the up-down shake in the Z direction of the table 2.

Although the type of the light 6 does not matter in principle, it is preferable to employ a coherent light having straightness to detect the attitude of the table 2 because it has less noise. Therefore, the light projecting means 31 employs the laser transmitter 13 as a light source, and converts the laser light 6 projected from one laser transmitter 13 into two optical paths parallel to the set path A by the optical member 7 such as a beam splitter or a mirror. And the light is projected onto a set of light receivers 5a and 5b and a set of light receivers 5c and 5d located on the front and back of the table 2, respectively. This provides a simple configuration for forming two detection optical paths from one light source. Also, by making these optical members into a unit as one light projecting means 31,
By adjusting the mutual positional relationship independently, the parallel accuracy of the two optical paths can be easily guaranteed.

In one embodiment, the guide 1 and the electromagnets 9a1 to 9a for the magnetic bearing 9 shown in FIG.
6, 9b1 to 9b6, that is, the floating amount of the guide 1 of the table 2 with respect to the guide surface 1a and the free amount thereof are generally 0.5 mm or less.
Is performed within this clearance and within a range where the table 2 and the guide 1 do not come into contact with each other. When the guide 1 has a bend larger than the clearance, the table 2 and the guide 1 are physically
It is needless to say that the table 2 interferes and it becomes difficult to move the table 2 along the guide 1. However, since the attitude of the table 2 is not controlled based on the guide surface of the guide 1, it is not always necessary that the guide 1 is processed with high precision.

In the above example, five degrees of freedom other than the axial direction of the guide 1, that is, the X direction, can be controlled. However, if necessary, the number of light receivers 5a to 5d can be reduced to achieve simplification and cost reduction. Needless to say, the number of axes that can control only those of the table 2 that need to be regulated among the postures and runouts may be reduced.

In the examples shown in FIGS. 6 to 8, the light receiving means 32 receives an reflected light from the optical member 10 such as a half mirror on the table 2 with respect to the same projection light 6 and an autocollimator as a light receiver. Emitter / receiver 1 as an angle detector
1 is combined with a light receiver 5 such as a PSD for receiving the projection light 6 transmitted through the optical member 10. According to this, as shown in FIG. 8, the actual light receiving point does not deviate from the reference light receiving point of the light emitting and receiving device 11 and the actual light receiving point deviates from the reference light receiving point of the light receiving device 5.
Of the actual light receiving point with respect to the reference light receiving point of the light emitting and receiving device 11 and the reverse of the light receiving device 5
The rotation of the table surface 2a about the Z-axis and the inclination in the X-direction, that is, the rotation about the Y-axis, can be detected on the basis of the relationship between the reference light-receiving point and the actual shift of the light-receiving point.

Therefore, the judging means 8 synthesizes the judgment results of the judging section 12 based on the output from the light emitting and receiving device 11 and the judging section 18 based on the output from the light receiving device 5 to obtain the attitude and the shake of the table 2. Among them, a moving state requiring regulation is determined and inputted to the magnetic bearing control device 4.

In the example shown in FIG. 9, the light receiving means 32 is
4 is the same reflection through two optical members 20 such as mirrors at two locations in the Y direction orthogonal to the setting path A on the table 2 from two parallel projection lights 6 from the same light projecting means 31. One optical interferometer 14 such as a laser interferometer that receives light in the interference state on the path 35 is used. According to this, the table 2 accompanying the parallel movement of the reflection surface of the optical member 20
In other words, if there is a motion other than the rotation around the X axis, the incident state when the two parallel projection lights 6 enter the optical interferometer 14 via the optical members 10 changes, Many movement states of the table 2 can be detected by one optical interferometer 14.

More specifically, the laser light 6 emitted from the laser oscillator 13 is split into two optical paths by the optical member 7, respectively, is reflected by the half mirror 10 on the table 2, and is reflected from the optical member 7 in the light projecting means 31. The light enters the optical interferometer 14 via the same reflection path 35 and interferes with each other. At this time, if the table 2 rotates around the Z axis, the incident points of the laser beams 6 in the two optical paths on the optical interferometer 14 are shifted, and the degree of interference changes. Can be detected around the Z axis. When the table 2 is tilted in the X direction, that is, when the table 2 is rotated about the Y axis, the two laser beams 6 are incident on the optical interferometer 14 in an overlapping manner, ie, the incident positions, that is, the actual light receiving points on the optical interferometer 14. Is shifted from the reference light receiving point, the rotation of the table 2 around the Y axis can be detected from the change in the light receiving condition in the optical interferometer 14 due to the shift of the light receiving point. Therefore, the judging means 8 may judge these matters.

The processing machine according to the embodiment of the present invention shown in FIG. 10 is an example in which the high-precision magnetic bearing linear stage shown in FIGS. 6 to 8 is applied to an ultra-precision processing machine. This processing machine is an ultra-precision lathe having a two-axis orthogonal table.

On the bed 16, the axial direction (X
The table 2 moving along the direction of the table 2 is supported by the magnetic bearing 9 in a non-contact manner with respect to the guide 1, and the magnetic bearing 9 is controlled by the magnetic bearing control device 4 based on detection data of the moving state of the table 2 by the detecting means 22. Is done.

An optical member 10 such as a half mirror and a light receiver 5 are mounted on the table 2 as a part of the light receiving means 32, and a tool rest 17 and a tool (tool) 28 are mounted thereon. Also, a magnetic bearing 43 is provided in the same structure as the magnetic bearing 9 between a guide 41 provided adjacent to the guide 1 on the bed 16 in a direction orthogonal to the guide 1 and a table 42 guided by the guide 41, and is not shown. Is provided with a detecting means for detecting the moving state of the table 42 and a magnetic bearing control device for controlling the magnetic bearing 43 in the same manner as the magnetic bearing 9 in order to correct the moving state of the table 42 based on the detection result by the detecting means. The table 42 has the works spindle 19 and the work 29 attached to its tip. Although the processing machine of this example performs processing based on the NC data from the NC device 30, both the tool 28 and the work 29 involve the highly linear movement of the tables 2 and 42, and high-precision ultraprecision processing that has never been achieved before. You can get the machine.

[0046]

As described above, according to the present invention, the swing and attitude of the table are set by performing feedback control of the active type magnetic bearing based on the data of the swing and attitude of the table detected by the position detecting device. Correction is performed so as to correctly follow the path, and a high-precision straight-running accuracy can be obtained without being affected by the accuracy of the processing and installation of the guide.

[Brief description of the drawings]

FIG. 1 is a plan view showing one magnetic bearing linear stage according to an embodiment of the present invention.

FIG. 2 is a side view of the magnetic bearing linear stage of FIG. 1;

FIG. 3 is a plan view schematically showing a state of detecting an appropriate moving state of a table on the magnetic bearing linear stage of FIG. 1;

FIG. 4 is a plan view schematically showing a state of detecting an improper moving state of the table in the magnetic bearing linear stage of FIG. 1 (yawing state).

5A and 5B show a specific example of a magnetic bearing in the magnetic bearing linear stage of FIG. 1, wherein FIG. 5A is a plan view and FIG.

FIG. 6 is a plan view showing another example of the magnetic bearing linear stage according to the embodiment of the present invention in a state where a table is appropriately moved.

FIG. 7 is a plan view showing a yawing state of the table in the magnetic bearing linear stage of FIG. 6;

FIG. 8 is a plan view showing a state in which the table swings in the Y direction on the magnetic bearing linear stage in FIG. 6;

FIG. 9 is a plan view showing another example of the magnetic bearing linear stage according to the embodiment of the present invention in a state where the table is appropriately moved.

FIG. 10 is a side view showing the ultra-precision processing machine according to the embodiment of the present invention.

FIG. 11 is a sectional view showing a conventional hydraulic static pressure stage.

[Description of Signs] 1 Guide 1a Guide surface 2 Table 2a Table surface 4 Magnetic bearing control means 5, 5a-5d Light receiver 6 Laser light 7, 10, 20 Optical member 8 Judgment means 9 Magnetic bearings 9a1-9a6, 9b1-9b6 Electromagnet 11 Light emitter / receiver 12 Judgment unit 13 Laser oscillator 14 Optical interferometer 21-23 Detecting means 31 Light projecting means 32 Light receiving means

Claims (8)

[Claims] 1. A table driven linearly, a linear guide for guiding the movement of the table during the linear drive along a set path, and a table guided by the guide is supported without contact with the guide. A magnetic bearing, and an active type magnetic bearing having an attitude or a runout adjustment characteristic with respect to a guide of the table as a magnetic bearing, and a table in a set path. The required movement state of the posture and the shake of the magnetic bearing is detected from the outside, and the adjustment characteristic of the magnetic bearing is controlled based on the data related to the detection to correct the necessary movement state of the table on the set path. A method for correcting the moving state of the table of the magnetic bearing linear stage. 2. A table driven linearly, a linear guide for guiding the movement of the table during the linear drive along a set path, and a table guided by the guide is supported in non-contact with the guide. A magnetic bearing linear stage provided with a magnetic bearing, wherein the magnetic bearing is an active type magnetic bearing having an adjustment characteristic of a posture or runout with respect to a table guide,
Detecting means for externally detecting a required movement state of the table attitude and deflection on the set path, and controlling the adjustment characteristics of the magnetic bearing based on the detection data from the detecting means to perform necessary movement of the table on the set path A magnetic bearing linear stage provided with a magnetic bearing control means for correcting a state. 3. The detecting means comprises: a light projecting means for projecting light in a predetermined direction from a predetermined position outside the moving table; and a light receiving means for receiving light from the light projecting means at a predetermined position on the moving table. Or a light receiving means for receiving light at a predetermined position outside the moving table via an optical member at a predetermined position on the moving table, and a light receiving condition of the light receiving means being compared with a reference condition. 3. The magnetic bearing linear stage according to claim 2, further comprising: a determination unit configured to determine a necessary movement state in the set path. 4. The magnetic bearing linear stage according to claim 3, wherein the light projecting means projects light so as to go straight in parallel with the set path. 5. A light receiving means comprising: a set of two light receiving units which receive the same projection light one after another on a table surface;
The magnetic bearing linear according to any one of claims 3 and 4, wherein two light receivers that individually receive two projection lights at two positions in a direction orthogonal to a set path on the table surface are used in combination. stage. 6. The light receiving means is a composite of a light receiver for receiving reflected light from the optical member on the table and a light receiver for receiving the projected light transmitted through the optical member for the same projection light. The magnetic bearing linear stage according to any one of claims 3 and 4, which is used. 7. A light receiving means for receiving two parallel projection lights in the same reflection path passing through two optical members in a direction orthogonal to a set path on the table in an interference state. The magnetic bearing linear stage according to any one of claims 3 and 4, which uses a meter. 8. A processing machine for processing a work with a tool accompanied by a relative movement of the tool and the work in a straight line, wherein the tool table or the work table driven in a straight line is provided. A processing machine comprising the magnetic bearing linear stage according to any one of the preceding claims.