JP3183913B2 - Linear motion support device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear motion support device suitable for supporting an element requiring high precision positioning, such as a scanning mirror of an optical interferometer or a precision linear table.

[0002]

2. Description of the Related Art As is well known, a support device for supporting a scanning mirror of an optical interferometer and a precision linear table is required to have a function of positioning them with high precision. In order to cope with such a demand, usually, a movable body which is guided by a guide mechanism and moves linearly smoothly is provided, and the movable body supports a supported object such as a scanning mirror and the movable body is moved by a precision ball screw feed mechanism. The structure to move by is adopted.

[0003] However, the supporting device employing such a mechanical positioning method has a problem that the components must be machined with extremely high precision. Further, even if a part is machined with high precision, the influence of backlash of the ball screw cannot be completely avoided, so that the positioning precision is limited. Further, in a severe temperature environment or a special environment such as under a high vacuum, it has been difficult to use the screw for a long time due to problems such as lubrication of a ball screw.

In order to solve such a problem, there is a method of supporting the object to be supported by a leaf spring and displacing the leaf spring by a linear actuator.
In this method, the range of the position that can be positioned is limited by the amount of deflection of the leaf spring, so that it is difficult to perform positioning over a long distance range.

[0005]

As described above, in the conventional so-called linear motion support device, the effects of mechanical errors appear, it is difficult to use the device for a long time in a special environment, or positioning is performed over a long distance range. Or it is difficult to exert a reliable support function and a highly accurate positioning function over a long distance range over a long period of time. Accordingly, an object of the present invention is to provide a linear motion support device that can solve all of the above-described problems.

[0006]

In order to achieve the above object, a linear motion supporting apparatus according to the present invention is provided with a fixed body and an axially movable body disposed near the fixed body to support a supported object. A movable body to be supported, a magnetic bearing device for supporting the movable body in a non-contact manner with the fixed body, an axial position detecting means for detecting an axial position of the movable body in a non-contact manner, And a control means for controlling the electromagnetic force generating mechanism based on the position information and the target position information obtained by the axial position detecting means.

[0007]

The movable body supporting the object to be supported is supported by the magnetic bearing device in a non-contact manner with respect to the fixed body. In addition, the position of the movable body in the axial direction is detected by the axial position detecting means without contact with the movable body. Further, the moving force in the axial direction to the movable body is given by the electromagnetic force generating mechanism in a non-contact manner with the movable body. Therefore, no lubricating oil is required because the movable body can be moved without friction. Therefore, it can be used for a long time even in a special environment. In addition, since the movable body can be moved without requiring a mechanical connection feed mechanism, there is no room for error such as backlash in positioning. For this reason, highly accurate positioning becomes possible. Furthermore, if, for example, a voice coil motor is used as the electromagnetic force generating mechanism, highly accurate positioning over a long distance can be realized without deteriorating the advantages described above.

[0008]

Embodiments will be described below with reference to the drawings. FIG. 1 shows a linear motion support device according to one embodiment of the present invention,
Here, a linear motion support device for supporting a scanning mirror of an optical interferometer for measuring a gas distribution state is shown.

In FIG. 1, reference numeral 1 denotes a fixed body.
The fixed body 1 includes a base 2 and a cylindrical body 3 made of a non-magnetic material and fixed to the base 2. A movable body 4 formed in a substantially columnar shape is provided in the cylindrical body 3.
Are arranged so as to be movable in the axial direction.

The movable body 4 is made of a magnetic material, and the right half in FIG. 1 is formed hollow. The left half of the movable body 4 in FIG. 1 is formed in a structure in which a central rod portion 5, a cylindrical hollow portion 6, and an outer cylindrical portion 7 are arranged concentrically. A mirror support 8 is provided at the right end of the movable body 4 in FIG.
The scanning mirror 9 is fixed to the mirror support 8.

The main elements 10a and 10b of the magnetic bearing device 10 for supporting the movable body 4 in a non-contact manner with the movable body 4 and the cylindrical body 3 are provided at two places in the axial direction, that is, in FIG. They are provided at positions indicated by arrows A and B, respectively.

The magnetic bearing device 10 is of a suction support type.
Of the main elements 10a and 10b, the main element 10a provided at the position indicated by the arrow A is representatively configured as shown in FIG. That is, the main element 10
“a” denotes yokes 11 a and 11 fixed at 90 ° intervals in the circumferential direction on the inner circumferential surface of the cylindrical body 3 and with the magnetic pole faces facing the axis.
b, 11c, 11d, the coils 12a, 12b, 12c, 12d mounted on these yoke, and the outer peripheral surface of the movable body 4 are spaced 90 degrees in the circumferential direction on the outer peripheral surface, and over substantially the entire length of the movable body 4. Magnetic poles 13a, 13 formed in a relationship extending
3b, 13c, 13d, and a movable body 4 between these convex magnetic poles.
Flat surfaces 14a, 14b, 14c, 1 formed so as to extend over substantially the entire length thereof and used for radial displacement detection.
4d, and radial position detectors 15a, 15b, 15c, and 15d that are fixed to the cylindrical body 3 in relation to each other and detect the distance between the flat surfaces.

Each yoke 11a, 11b, 11c, 11d
Has two magnetic pole surfaces 16a and 16b, as shown in FIG. 1 as a representative of the yoke 11c.
a, 16b are fixed to the inner surface of the cylindrical body 3 so as to be arranged in the axial direction. Each yoke 11a, 11b, 11c, 11
d, coils 12a, 12b, 12c, and 12d
Are composed of a bias coil 17 and a control coil 18, respectively. The bias coils 17 mounted on the yoke opposing the movable body 4 are connected in series so as to generate magnetic fluxes in opposite directions, and the control coils 18 mounted on the yoke are connected in the same direction. They are connected in series to generate a magnetic flux.

Each yoke 11a, 11b, 11c, 1
The two magnetic pole surfaces 16a and 16b of 1d and the magnetic pole surfaces of the four convex magnetic poles 13a, 13b, 13c and 13d provided on the movable body 4 are provided on the movable body 4 in order to stabilize the magnetic resistance therebetween. It is formed into a cylindrical curved surface centering on the axis. The main element 10b is configured similarly to the main element 10a.

On the left side of the movable body 4 in FIG. 1, an electromagnetic force generating mechanism 20 for selectively applying an axial moving force to the movable body 4 in a non-contact manner is provided between the movable body 4 and the cylindrical body 3. Is provided. The electromagnetic force generating mechanism 20 is, similarly to a known voice coil motor, fixed to the inner peripheral surface on the open end side of the outer cylindrical portion 7 and radially magnetized annular permanent magnet 21. And a cylindrical coil 22 fitted in the cylindrical hollow portion 6 in a non-contact manner. Note that the base end of the tubular coil 22 is fixed to the tubular body 3.

On the other hand, on the outer peripheral surface of the mirror support 8, there is provided an auxiliary plate 2 disposed so as to extend along the axis of the movable body 4.
3 has one end fixed. The lower surface of the auxiliary plate 23 in FIG. 1 is formed on an inclined surface 24 inclined with respect to the axis of the movable body 4 as shown in FIG. An axial position detector 25 that detects the position of the movable body 4 in the axial direction from the distance from the inclined surface 24 is fixed to the fixed body 1. The axial position detector 25, the cylindrical coil 22, the bias coil, the control coil, and the radial position detector constituting the main elements 10a and 10b of the magnetic bearing device 10 described above are provided by the control device shown in FIG. 31.

The control device 31 includes a magnetic bearing control unit 32,
An axial position control unit 33 is provided. FIG. 4 shows a magnetic bearing control unit 32 for controlling the energization of the coils 12a to 12d of the main element 10a.
The control unit for controlling the energization of each coil b is omitted.

The magnetic bearing control unit 32 outputs the outputs of the four radial position detectors 15a to 15d to a processing circuit 34, respectively.
And converted to radial displacement. And
These displacement amounts are introduced into the control circuit 35 to determine operation amounts from the difference from the reference position, and these operation amounts are converted into currents by the current amplifier 36, and the currents are supplied to the control coils 18 of the coils 12a to 12d. I have to. Also, the coil 12a
A constant current is supplied from the power supply 37 to the bias coils 17 of 12 to 12d. The same control is performed for the main element 10b. With this control, the movable body 4 is floated completely out of contact with the fixed body 1 and above the reference position in the radial direction. In this example, the offset signal F is superimposed on the obtained operation amount so that the flying position can be set to an arbitrary position in the radial direction.

On the other hand, the axial position control unit 33 outputs the output of the axial position detector 25 and the radial position detectors 15a to 15a.
d is introduced into a processing circuit 38, and this processing circuit 38
The axial position detector 2 according to the radial position of the movable body 4
The true axial position signal obtained by removing the error appearing in the output of No. 5 is obtained. Then, a deviation between the obtained axial position signal and the target position signal H is obtained by the control circuit 39, this deviation is converted into a current by the current amplifier 40, and this current is caused to flow through the cylindrical coil 22. With this control, the movable body 4 is moved to the target position and stopped at this target position.

With such a configuration, the magnetic bearing device 1
When 0 is operated, each bias coil 17 is energized with a constant current, and each control coil 18 is energized with a current having a level corresponding to the amount of displacement of the movable body 4 in the radial direction and a polarity corresponding to the direction of displacement. Be inspired. That is, the yoke 11a
11d and the magnetic gap length between the pole faces of the convex magnetic poles 13a to 13d are determined by the radial position detectors 15a to 15d.
It is determined based on the output of 5d. Then, for a portion where the magnetic gap length is widened, the control coil 18 is energized so as to increase the magnetic flux passing through the magnetic gap. Also, for the part where the magnetic gap length is narrow,
Control coil 18 is energized to reduce magnetic flux through the magnetic gap. For this reason, the movable body 4 is
, Is completely non-contact supported by the magnetic bearing device 10.

When the target position signal H is applied, the electromagnetic force generating mechanism 20 operates, and applies a moving force in the axial direction to the movable body 4 in a non-contact manner on the same principle as a known voice coil motor. Then, the movable body 4 is stopped at the target position. In this case, the position detection in the axial direction necessary for the position control is performed by the auxiliary plate 23.
Are detected in a non-contact manner by an axial position detector 25 that targets an inclined surface 24 provided in the sensor. Therefore, driving and positioning in the axial direction are also performed without contact. Further, by detecting the speed component in the processing circuit 38 and inputting the detected speed component to the control circuit, the speed control can be performed in the same manner as the positioning.

As described above, the movable body 4 supporting the object to be supported is supported in a non-contact manner with the fixed body 1 by the magnetic bearing device 10.
The position of the movable body 4 in the axial direction is detected by the inclined surface 24 and the axial position detector 25 in a non-contact manner with the movable body 4. Further, the moving force in the axial direction to the movable body 4 is applied to the movable body 4 in a non-contact manner by the electromagnetic force generating mechanism 20. Therefore, since the movable body 4 can be moved without friction, lubricating oil is not required. Therefore, it can be used for a long time even in a special environment. Further, since the movable body 4 can be moved without requiring a mechanical connection feed mechanism, there is no room for error such as a backlash in positioning, and high-precision positioning can be performed. In addition, since the movable body 4 is moved and positioned in the axial direction by using the voice coil motor type electromagnetic force generating mechanism 20, it can be driven over a long distance and has sufficient positioning accuracy. it can. Therefore, even under a special environment such as a vacuum, highly accurate positioning can be stably performed over a long distance range for a long period of time.

This embodiment also has the following advantages. That is, in order to control the magnetic bearing device 10, it is necessary to detect the radial position of the movable body 4 by some means. In this embodiment, a flat surface is formed between the convex magnetic poles 13a to 13d on the outer peripheral surface of the movable body 4. 14a to 14d are provided, and the flat surfaces 14a to 14d are used as radial position detection surfaces. In this way, the flat surfaces 14a to 14d are
13d, the flat surfaces 14a to 14d are not only easily processed, but also the movable body 4
There is no risk that the flat surfaces 14a to 14d will be damaged when they come into contact with the side of the cylinder 3, and furthermore, the influence of the magnetic field of the magnetic bearing on the position detector can be eliminated, and the reliability can be improved. . The magnetic pole surfaces of the respective yokes 11a to 11d and the magnetic pole surfaces of the convex magnetic poles 13a to 13d provided on the movable body 4 are formed into cylindrical curved surfaces around the axis of the movable body 4. Therefore, the magnetic resistance between the two magnetic pole faces can be stabilized, and the movable body 4 can be automatically returned to the original position when a rotational force is applied. Further, since the magnetic bearing control unit 32 can externally supply the offset signal F, the so-called attitude of the movable body 4 can be variably set. 5 and 6 show a linear motion support device according to another embodiment of the present invention, in which a linear motion support device for supporting a precision linear table is shown.

In these figures, reference numeral 101 denotes a fixed body. The fixed body 101 includes a base 102 and a non-magnetic cylindrical body 103 fixed to the base 102. In the cylindrical body 103, a movable body 104 formed in a substantially columnar shape is arranged so as to be movable in the axial direction of the cylindrical body 103.

The movable body 104 is made of a magnetic material, and the right half in FIG. 5 is hollow. Also,
The left half of the movable body 104 in FIG.
, A cylindrical hollow portion 106 and an outer cylindrical portion 107 are concentrically arranged. And movable body 1
04 are connected to the table 110 via connecting members 108 and 109.

The movable body 104 and the cylindrical body 103 include the cylindrical body 1
The main elements 111a and 111b of the magnetic bearing device 111 for supporting the movable body 104 in a non-contact manner at 03 are provided at two positions in the axial direction, that is, at positions indicated by arrows C and D in FIG.

The magnetic bearing device 111 is of a suction support type. Of the main elements 111a and 111b, the main element 111a provided at the position shown by the arrow C is representatively shown as shown in FIG. It is configured. That is, the main element 111a is attached to the inner circumferential surface of the cylindrical body 103 in the circumferential direction.
Yoke 112a, 112b, 112c fixed at 0 degree intervals and with the magnetic pole faces facing the axis, coils 113a, 113b, 113c mounted on these yoke,
Convex magnetic poles 114a, 114b, 114c formed at intervals of 120 degrees in the circumferential direction on the outer peripheral surface of the movable body 104 and formed so as to extend over substantially the entire length of the movable body 104;
It is formed between these convex magnetic poles so as to extend over substantially the entire length of the movable body 104 and to extend obliquely with respect to the axis of the movable body 104, and is used for radial displacement detection and axial position detection. A position detector 116 that is fixed to the cylindrical body 103 in a relationship between the inclined surfaces 115a, 115b, and 115c and each yoke and detects a distance between each inclined surface.
a, 116b and 116c.

Each yoke 112a, 112b, 112c is
As shown in FIG. 5 representatively of the yoke 112b, two yoke surfaces 117a and 117b are provided.
7a and 117b are arranged in the axial direction.
It is fixed to the inner surface of. Each yoke 112a, 112b,
Coil 113a, 113b, 11 attached to 112c
3c is a bias coil 118 and a control coil 1 respectively.
19.

Each yoke 112a, 112b, 112
c, and three convex magnetic poles 114a, 114b, 114 provided on the movable body 104.
The magnetic pole surface c is formed in a cylindrical curved shape centered on the axis of the movable body 104 in order to stabilize the magnetic resistance between them. The main element 111b is also used for the main element 111b.
It has the same configuration as a.

On the left side of the movable body 104 in FIG. 5, the movable body 104 and the cylindrical body 103 are provided with an electromagnetic force generating mechanism 1 for selectively applying an axial moving force to the movable body 104 in a non-contact manner.
20 are provided. This electromagnetic force generating mechanism 120
Similarly to the known voice coil motor, the outer cylindrical portion 107
An annular permanent magnet 121 fixed to the inner peripheral surface on the open end side and magnetized in the radial direction, and a cylindrical coil 12 entirely formed in a cylindrical shape and fitted into the cylindrical cavity 106 in a non-contact manner.
And 2. Note that the base end of the tubular coil 122 is fixed to the tubular body 103.

The cylindrical coil 122, the bias coils 118, the control coils 119, and the position detectors 116a, 116b, 116c constituting the main elements 111a, 111b of the magnetic bearing device 111 are controlled by a control (not shown). Connected to device.

This control device comprises a magnetic bearing control unit and an axial position control unit as in the above embodiment.
The magnetic bearing control unit is basically configured in the same manner as in the above embodiment. For example, taking the main element 111a as an example, the reference position of the movable body 104 is determined based on the outputs of the three position detectors 116a, 116b and 116c. Is calculated, and the current of the control coil 119 is controlled so as to make the deviation amount zero, whereby the movable body 104 is completely in non-contact with the fixed body 101.
And it is made to float above the reference position in the radial direction. Also in this example, the flying position can be set to an arbitrary position in the radial direction by superimposing the offset signal F.

On the other hand, the axial position control section includes the position detector 1
A position signal corresponding to the axial position of the movable body 104 is obtained from the outputs of 16a, 116b, and 116c. Then, the deviation between the obtained axial position signal and the target position signal is converted into a current by a current amplifier, and this current is caused to flow through the cylindrical coil 122. Therefore, in this example, the movable body 1
04 formed on the inclined surfaces 115a, 115b, 115c
In combination with the position detectors 116a, 116b and 116c, the position detection of the movable body 104 in the radial direction and the position detection in the axial direction are simultaneously performed.

With this configuration, the same effect as in the above embodiment can be obtained. In this embodiment, since the inclined surfaces 115a, 115b, and 115c are used for both the position detection in the radial direction and the position detection in the axial direction, the whole can be simplified and the number of detectors can be minimized. Can be suppressed.

The present invention is not limited to the above embodiments. That is, in the above-described embodiment, the bias coil is incorporated in the magnetic bearing device, but the bias coil may be replaced with a permanent magnet. Further, in the above-described embodiment, six detectors are used, but position detection can be performed with only five detectors. Further, in the above-described embodiment, as a means for detecting the axial position of the movable body, an inclined surface is provided on the movable body side and a detector is provided on the fixed body,
Although the distance from the inclined surface is detected by a detector, the present invention is not necessarily limited to this detection method. For example, a code scale may be attached to a movable body, and this may be optically read. In short, any configuration may be used as long as the position of the movable body in the axial direction can be detected without contact. Further, in each of the above-described embodiments, two sets of main elements of the magnetic bearing device are provided in the axial direction, but three or more sets may be provided.

[0036]

As described above in detail, according to the present invention, even under a special environment such as a vacuum, the movable body can be positioned with high accuracy over a long distance without lubrication.

[Brief description of the drawings]

FIG. 1 shows a linear motion supporting apparatus according to an embodiment of the present invention;
Sectional drawing cut | disconnected along the SS line in FIG.

FIG. 2 is a cross-sectional view of the linear motion supporting device taken along the line RR in FIG. 1 and viewed in the direction of the arrow;

FIG. 3 is a perspective view showing only a movable body in the linear motion support device.

FIG. 4 is a block diagram of a control device in the linear motion support device.

FIG. 5 is a longitudinal sectional view of a linear motion support device according to another embodiment of the present invention.

FIG. 6 is a cross-sectional view of the linear motion support device taken along line XX in FIG. 5 and viewed in the direction of the arrow.

[Explanation of symbols]

1, 101: fixed body, 4, 104: movable body, 10, 111: magnetic bearing device, 11a to 11d, 1
12a-112c ... yoke, 12a-12d, 113a-
113c ... coils 13a to 13d, 114a to 114c
... convex magnetic poles, 14a to 14d ... flat surfaces, 15
a to 15d: radial position detector, 17, 118: bias coil, 18, 119: control coil, 20, 1
20: electromagnetic force generating mechanism, 21, 121: permanent magnet,
22, 122: cylindrical coil, 23: auxiliary plate, 24
... Slope surface, 25 ... Axial position detector, 31 ... Control device, 32 ... Magnetic bearing control unit, 33 ... Axial position control unit, 115
a to 115c: inclined surface, 116a to 116c: position detector.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H02N 15/00

Claims (4)

(57) [Claims] 1. A fixed body, a movable body arranged in the vicinity of the fixed body movably in the axial direction to support an object to be supported, and a magnetic bearing device for supporting the movable body in a non-contact manner by the fixed body. An axial position detecting means provided on the fixed body and the movable body to detect an axial position of the movable body in a non-contact manner; and provided on the fixed body and the movable body, An electromagnetic force generating mechanism that applies an axial moving force in a non-contact manner;
Control means for controlling the electromagnetic force generating mechanism based on the position information and the target position information obtained by the axial position detection means , wherein the magnetic bearing device surrounds the movable body of the fixed body Rank
Place each magnetic pole surface in the circumferential direction
A plurality of yokes fixed at intervals, coils respectively mounted on these yokes, and a magnetic pole surface of each of the yokes on the outer peripheral surface of the movable body,
And a plurality of convex magnetic poles protruding in a relationship extending in the axial direction.
And a surface facing the convex magnetic pole on the outer peripheral surface of the movable body is movable.
The movable body is formed in a cylindrical shape with its axis at the center, and is located between the convex magnetic poles on the outer peripheral surface of the movable body.
A plurality of position detectors each formed in an axially extending relationship
Outgoing surface, provided on the fixed body facing these position detection surfaces,
A plurality of sensors that detect the distance between each of the above position detection surfaces without contact
And a position detector.
4. The linear motion support device according to item 1. 2. The method according to claim 1, wherein the plurality of position detection surfaces are flat surfaces.
Linear movement supporting apparatus according to claim 1, wherein the door. 3. A fixed body and an axially moved body near the fixed body.
A movable body movably disposed to support the supported object,
Magnetic bearing device for supporting a movable body in a non-contact manner with the fixed body
And the movable body provided on the fixed body and the movable body.
Position detecting means for detecting the axial position of the object in a non-contact manner
And the movable body provided on the fixed body and the movable body.
An electromagnetic force generating mechanism that applies an axial moving force to the
Position information and target position obtained by the axial position detecting means
Control means for controlling the electromagnetic force generating mechanism based on information
Comprising the door, the magnetic bearing device, position surrounding the movable body of the fixed body
Place each magnetic pole surface in the circumferential direction
A plurality of yokes fixed at intervals, coils respectively mounted on these yokes, and a magnetic pole surface of each of the yokes on the outer peripheral surface of the movable body,
And a plurality of convex magnetic poles protruding in a relationship extending in the axial direction.
And a portion located between the convex magnetic poles on the outer peripheral surface of the movable body.
A plurality of position detectors each formed in an axially extending relationship
Outgoing surface, provided on the fixed body facing these position detection surfaces,
A plurality of sensors that detect the distance between each of the above position detection surfaces without contact
A position detector, wherein the axial position detection means is fixed to the movable body,
And extending along the axial direction of the movable body and
It has a slope inclined with respect to the axis of the movable body
An auxiliary member, provided in the fixed body, in front of the auxiliary member;
A detector that detects the distance to the inclined surface in a non-contact manner.
A linear motion support device characterized by the following. 4. The apparatus according to claim 1, wherein said electromagnetic force generating mechanism comprises a voice coil motor .
The linear motion supporting device according to any one of the above.