JPH05138484A - Precision positioning fine moving feed device and system - Google Patents

Abstract

PURPOSE:To provide a precision positioning fine moving feed device and system which are capable of taking a large stroke high in resolution and speed and which are compact and strong against a load in the shaft direction and against a moment load, and to eliminate a problem of small vibration at the time of positioning. CONSTITUTION:A shaft direction expansion part 6 is provided on a nut part 5 screwed in a feed screw shaft 3, coarse motion is carried out by the feed screw shaft 3 and a screw feeding mechanism of the nut part 5, and fine moving is carried out by the shaft direction expansive part 6. The shaft direction expansive part 6 is furnished with an elastic member 7 which is free to elastically deform in the shaft direction and rigid in the rotational direction, a small displacement means 8 free to expand in the shaft direction and a detection means 9 to detect shaft direction displacement of the elastic member 7, and it is constituted to control a stroke of the small displacement means 8 in accordance with a detected value detected by the detection means 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fine positioning fine feed device and system, such as a machine tool or a robot, which requires precise feed and positioning.

[0002]

2. Description of the Related Art Conventionally, there has been a demand for a higher density and higher precision feeding device in the semiconductor industry and the biotechnology industry. However, with regard to the machining precision of general machine tools, it has been desired to improve the precision to the micron level. It's starting.

A ball screw device is often used as a conventional feeder for precision positioning. That is, by rotating the screw shaft by a pulse motor, the nut screwed onto the screw shaft is moved linearly to control the feed of the table attached to the nut.

[0004]

However, the resolution of the conventional ball screw device depends on the resolution (pulse number / rotation number) of the lead of the screw shaft and the motor for rotating the screw shaft, and enhances the resolution of the feeding device. Therefore, a ball screw with a small lead and a motor with high resolution are required.

However, as the lead of the screw shaft is made smaller, the influence of machining error becomes larger, and it is difficult to make the lead smaller. Further, in order to increase the resolution of the motor, it is necessary to improve the accuracy and resolution of the encoder. However, in order to increase the accuracy and resolution of the encoder,
It is necessary to mechanically cut the slits of the encoder into smaller pieces, which limits processing accuracy.

Further, in order to improve the resolution, there is a microstep system in which the drive is controlled by using a harmonic gear, or the control current is electrically divided into finer parts, and the like. Was the limit.

Further, there is also a problem that a command device having a high transmission frequency is required in order to electrically improve the resolution.

On the other hand, a feeding device using a minute displacement means such as a piezoelectric element or an electrostrictive element for positioning in nanometer units is also known, but the maximum displacement width of the piezoelectric element is very small. There was a big problem that the stroke was extremely short.

Therefore, in order to lengthen the stroke of the minute displacement means, a feeder called an inchworm (measuring insect) mechanism has been devised, and such an inchworm mechanism 10 is used.
The fine movement table 101 using the ball screw device 102
There is also proposed a device which is mounted on a coarse movement table 103 using a ball screw device 102 for coarse movement positioning and an inch worm mechanism 100 for precise positioning (see FIG. 9 (a)).

The inchworm mechanism 100 is, as shown in FIG. 9 (b), the first, second and third parts fitted to the shaft 104.
It is composed of the third piezoelectric cylinders 105, 106 and 107. Then, a voltage is applied to the first piezoelectric cylinder 105 and the second piezoelectric cylinder 106 is extended while being clamped on the shaft 104, and the third piezoelectric cylinder 10 is extended by a predetermined length.
7 is sent to the right side in the figure. Next, the first piezoelectric cylinder 105 is released to release the clamp, and the third piezoelectric cylinder 10 is released.
A predetermined voltage is applied to 7 and clamped on the shaft 104, the second piezoelectric cylinder 106 is contracted, and the first piezoelectric cylinder 105 is sent to the right side in the drawing. In this way, the first, second, and third piezoelectric cylinders 105, 106, and 107 are repeatedly operated to move in the linear direction.

However, in such a feeding device, since the fine motion table 101 of the inchworm mechanism 100 is mounted on the coarse motion table 103 using the ball screw device 102, the fine motion and coarse motion tables 101 and 103 are assembled. Have difficulty.

Further, since the fine movement table 101 of the inchworm mechanism 100 is mounted on the coarse movement table 103 of the ball screw device 102, the height of the device becomes high and it cannot be made compact. Such a problem becomes fatal when a multi-axis table is constructed.

Further, the fine movement table 101 of the inchworm mechanism 100 includes the first and third piezoelectric cylinders 105 and 107.
Since the clamp supports the axial position, a large load cannot be received in the axial direction, and the height of the device becomes high, so that there is a problem that it is weak against moment load.

On the other hand, in relation to the precision positioning, the conventional feeder has a problem that minute vibrations are generated during positioning. This is a phenomenon in which a table or the like causes minute vibrations due to inertial force when positioned at high speed.
When such a minute vibration occurs, the time required to complete the positioning of the table becomes long, which causes a problem of poor responsiveness.

The present invention has been made to solve the above-mentioned problems of the prior art. The object of the present invention is to perform precise positioning capable of feeding with an ultra-precision resolution and having a compact structure and a large stroke. It is to realize a fine feed device and system.

Another object of the present invention is to provide a fine positioning fine feed device and system capable of resolving the problem of minute vibrations and greatly shortening the positioning completion time.

[0017]

In order to achieve the above object, according to the present invention, a nut portion screw-engaged with a feed screw shaft and linearly moving with respect to the feed screw shaft by rotation of the feed screw shaft is provided. An axial expansion / contraction portion that is expandable / contractible in the axial direction of the feed screw shaft is provided to the nut portion, a feed member is attached to this axial expansion / contraction portion, and coarse feed of the feed member is performed by the feed screw shaft. It is characterized in that the fine movement feeding is performed by the axially expanding / contracting portion.

The axial expansion / contraction portion is an elastic member which is elastically deformable in the axial direction and rigid in the rotational direction, a minute displacement means capable of expansion / contraction in the axial direction, and a fine movement feed amount for detecting a fine movement feed amount to the nut portion. It is preferable to include a detection means.

Then, it is preferable to control the expansion / contraction amount of the fine displacement means based on the detection value detected by the fine movement feed amount detection means.

The minute displacement means is a means for displacing in the axial direction in proportion to the command value when a command value is given. For example, a piezoelectric element or an electrostrictive element, an actuator that expands and contracts by utilizing fluid pressure or thermal expansion, Various actuators using a voice coil, a magnetostrictive element, etc. can be used.

When a movable table is used as the member to be fed, the movable table is attached to the nut, the movable table is movably guided and held by the linear motion guide mechanism, and the feed screw shaft is rotated by the rotation driving means. It is preferable that the coarse feed is performed.

On the other hand, the fine positioning fine movement feed system of the present invention comprises a feed screw shaft, a nut portion screwed to the feed screw shaft, and a minute displacement means provided so as to be capable of expanding and contracting in the axial direction with respect to the nut portion. An axially extending / contracting portion, and a rotary driving means for coarsely feeding the nut portion to the feed screw shaft by a predetermined stroke by rotating the feed screw shaft by a predetermined amount based on a predetermined coarse movement control target signal; A fine movement feed amount detecting means for detecting a fine movement feed amount by the axial expansion / contraction portion, and a fine movement control device for driving and controlling the fine displacement means based on an output of the fine movement feed amount detecting means and a predetermined fine movement control target signal, And a command device for giving a coarse movement control target signal to the rotation driving means and a fine movement control target signal to the minute displacement means.

A coarse movement feed amount detecting means for detecting a coarse movement feed amount of the nut portion with respect to the feed screw shaft, and the rotation driving means based on an output of the coarse movement feed amount detecting means and a predetermined coarse movement control target signal. It is preferable to have a configuration including a coarse movement control device that drives and controls the.

Further, a converter is provided for converting the fine movement control target signal output from the command device to the fine movement control device from a digital signal to an analog signal, and the rotation driving means is controlled by a digital signal, and the axial expansion / contraction unit. It is preferable that the control is performed by an analog signal.

[0025]

In the fine positioning fine movement feed device having the above-mentioned structure, the feed screw shaft is rotationally driven to linearly move the nut portion by a predetermined amount, and the movement is attached to the nut portion via the axial expansion / contraction portion. Coarse feed of the member is performed. Further, the driven member is finely fed to the nut portion by driving the axially extending / contracting portion, which enables feeding with super-precision resolution. In this way, even if the stroke of the axial expansion / contraction portion is short, by combining the feed screw shaft and the axial expansion / contraction portion, it is possible to move at high speed during a long stroke.

Further, since the axially extending / contracting portion is provided on the nut portion, it can be made much more compact than the conventional type in which the tables are stacked.

Further, unlike the conventional inchworm mechanism, it does not clamp the shaft to support the axial position,
Since it is positioned and supported by the axial expansion / contraction part and the feed screw shaft, it can receive a large axial load as compared with the conventional inchworm mechanism, and since the height of the device configuration can be made short, it is also strong against moment load.

Further, minute vibrations at the time of positioning can be eliminated by, for example, applying an alternating current to the axial expansion / contraction portion so as to cancel the vibrations, and the time required to complete the positioning can be greatly shortened. it can.

In the fine positioning fine movement feed system of the present invention, the coarse movement and fine movement control target values are input to the command device. Then, the feed screw shaft is rotated by the rotation drive means based on the coarse movement control target signal output from the command device. With the rotation of the feed screw shaft, the nut part moves linearly, and the member to be fed is coarsely fed through the axial expansion / contraction part that moves integrally with the nut part, and is positioned at a predetermined coarse movement control target position. It

Further, based on the output of the fine movement feed detection means and a predetermined fine movement control target signal, the fine movement control device drives the fine displacement means of the axial extension / contraction portion to extend / contract, thereby moving the moving member to a predetermined fine movement control target position. Be positioned at.

On the other hand, coarse movement feed amount detecting means for detecting the coarse movement feed amount of the nut portion with respect to the feed screw shaft is provided, and rotation is performed based on the output of the coarse movement feed amount detecting means and a predetermined coarse movement control target signal. If the drive means is drive-controlled, the positioning can be controlled more precisely.

Further, a converter for converting the fine motion control target signal output from the command device to the fine motion control device from a digital signal to an analog signal is provided, and the rotation driving means is controlled digitally to control the axial expansion / contraction portion. If the control is performed by analog control, the command system for analog control and digital control can be realized by one command device.

Further, since the fine movement feed control is performed by analog control, the command device does not require a high frequency oscillation circuit for fine movement control, and the circuit configuration can be simplified.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to illustrated embodiments.

FIG. 1 (a) shows a conceptual configuration when the fine positioning fine movement feed device of the present invention is applied to a table transfer device such as a machine tool.

That is, the fine positioning fine movement feed device 1 moves the movable table 2 as a fed member in a linear direction, and is screwed onto the feed screw shaft 3 and the feed screw shaft 3 via balls 4. A nut portion 5 and an axially stretchable portion 6 that is axially stretchable with respect to the nut portion 5. The axial expansion / contraction portion 6 is integrally provided on one end surface of the nut portion 5, and the movable table 2 is attached to the axial expansion / contraction portion 6.

Then, the nut portion 5 is fed by a predetermined amount in the axial direction by the rotation of the feed screw shaft 3, and the table is moved integrally with the nut portion 5 via the axial expansion / contraction portion 6 and is coarsely fed by the predetermined amount. It Further, the axial expansion / contraction part 6 is expanded / contracted in the axial direction to feed the table in fine movements for precise positioning.

FIG. 1B shows a conceptual structure of the axial expansion / contraction part 6. The axial expansion / contraction part 6 includes an elastic member 7 elastically deformable in the axial direction and rigid in the rotation direction, and a minute displacement means 8 such as an axially expandable / contractible piezoelectric element or electrostrictive element.
Displacement detection means 9 as fine movement feed amount detection means for detecting the amount of axial extension / contraction of the axial extension / contraction part 6, that is, the fine movement feed amount.
And the stroke of the minute displacement means 8 is controlled based on the detection value detected by the displacement detection means 9.

As the minute displacement means, in addition to the piezoelectric element and the electrostrictive element, a thermal actuator that expands and contracts by utilizing the thermal expansion of an object, and expansion and contraction by fluid pressure as shown in FIGS. 1 (c) and 1 (d) are used. It is possible to apply various actuators that expand and contract in proportion to the command value, that is, based on the command value, such as the actuator 8a that operates, the voice coil, and the magnetostrictive element.

Further, as the displacement detecting means, for example, a resistance type sensor 9a such as a strain gauge as shown in FIG. 2 (a),
A sensor 9b that detects displacement as a voltage change using a piezoelectric element as shown in FIG. 7B, an electromagnetic induction sensor 9c such as a differential transformer or an eddy current sensor as shown in FIG.
An electrostatic capacitance type sensor as shown in FIG. 2D, and an optical interference type sensor 9 using an optical fiber as shown in FIG. 2E.
It is possible to use various sensors such as e, which can detect minute displacements.

FIG. 3 shows the control configuration of the fine positioning fine movement feed system of the present invention.

The movable table 2 to be transferred is guided in a linear direction by a linear motion guide mechanism 17. The linear motion guide mechanism 17 has a track rail 17a and rolling elements 17b on the track rail 17a. The guide mechanism main body 17c is slidably assembled.

The control system is roughly divided into a coarse movement control system for driving and controlling the feed screw shaft 3 and a fine movement control system for controlling the axial expansion / contraction portion 6.

The coarse movement control system includes a linear scale 10 for detecting the position of the movable table 2, a motor 11 as a rotation driving means for driving the feed screw shaft 3 to rotate,
Motor driver 12 for driving this motor 11
And a command device 13 for outputting to the motor driver 12 a command signal that is a target for coarse movement control.

On the other hand, the fine movement control system includes a fine displacement means driver 14 for driving the fine displacement means 8, a displacement detection means 9 for detecting a stroke of the fine displacement means 8 in the axial direction, and an expansion / contraction in the axial direction. And a fine movement control device 15 for controlling the movement of the section 6. A fine command control device 15 receives a digital command signal as a target of the fine motion control from the command device 13 after being converted into an analog signal via the D / A converter 16.

In the fine positioning fine movement feed system having the above structure, first, the target feed amount is input to the command device 13.

A command signal as a coarse control target is output to the motor driver 12 corresponding to the target feed amount, and the motor 11 is rotationally driven based on the command signal. The feed screw shaft 3 is rotated by the drive of the motor 11, the nut portion 5 is moved straight according to the rotation of the feed screw shaft 3, and the movable table 2 is coarsely fed to a predetermined position and stopped.

The coarse feed is controlled by using the linear scale 10 as the coarse feed amount detecting means, so that the motor driver 1 is constantly monitored while monitoring the position of the movable table 2.
It is also possible to perform closed loop control in which the motor driver 12 is fed back to 2 to function as coarse movement control means to correct the deviation from the target position.

After the feed screw shaft 3 is stopped, the movable table 2 is finely moved by the axial expansion / contraction part 6. This fine movement feed is performed with a resolution that is more precise than the resolution of coarse movement feed by the feed screw shaft 3. For example, the feed up to the micron unit is performed by the coarse feed, and the feed in the micron unit or less is performed in the axial expansion / contraction unit 6. It is supposed to be done in.

That is, the command signal which is the target of the fine movement control from the command device 13 is converted into an analog signal by the D / A converter 16 and input to the fine movement control device 15. A drive signal is output to the micro displacement means driver 14 based on this command signal, and the micro displacement means 8 such as a piezoelectric element expands and contracts. The stroke amount of the minute displacement means 8 is constantly detected by the displacement detection means 9 and fed back to the fine movement control device 15 to accurately determine the position of the movable table 2. By using the axial expansion / contraction part 6 in this way,
The resolution enables precision feed in nanometer units, which is not comparable to ball screws.

Further, even if the axial expansion / contraction part 6 has a short stroke, it can be moved at high speed during a long stroke by the feed screw shaft 3.

On the other hand, there is an error from the input target position due to the machining error of the lead of the feed screw shaft 3 or the thermal expansion of the feed screw shaft 3 due to the temperature change. The movable table 2 can be accurately positioned by performing correction by operating the direction expansion / contraction unit 6.

That is, data such as the machining error of the lead of the feed screw shaft 3 and the amount of thermal expansion in the axial direction of the feed screw shaft 3 due to the temperature change are input to the fine movement control device 15 in advance and input from this data and the command device 13. The correction amount may be calculated from the obtained target data. By inputting the calculated correction amount to the minute displacement means driver 14 and driving the minute displacement means 8 such as a piezoelectric element using this correction amount as a target value, the movable table 2 can be precisely positioned at a target position. it can.

Further, since the drive motor 11 for the feed screw shaft 3 is controlled by pulse and the axial expansion / contraction part 6 is controlled by two different control systems which are controlled by different analog command values, high resolution and high frequency are achieved. It is not necessary to use the oscillation command device 13, and the circuit configuration can be simplified, which is advantageous.

Further, there is a problem of minute vibration during positioning in relation to the precise positioning. This is a phenomenon in which the movable table 2 or the like causes minute vibrations due to inertial force even when it is positioned at a high speed. The problem of such minute vibration can be solved by operating the axial expansion / contraction portion 6 so as to cancel the vibration, and the positioning completion time can be greatly shortened.

FIG. 4 shows a more specific embodiment of the fine positioning fine movement feed device of the present invention.

That is, the apparatus of this embodiment has a nut portion 25 screwed onto the feed screw shaft 32, an axially extending / contracting portion 26,
The movable table 2 is attached to the flange portion 25a, and the nut portion 25, the axial expansion / contraction portion 26, and the flange portion 25a are integrally structured. A large number of balls 4 are rotatably interposed between the nut portion 51 and the thread groove of the feed screw shaft 3.

The axial expansion / contraction portion 26 is elastically deformable in the axial direction and rigid in the rotational direction, and a minute displacement means 28 such as a piezoelectric element interposed between the opposing surfaces of the nut portion 25 and the flange portion 25a. And displacement detecting means 29 for detecting the displacement in the axial direction.

The elastic member 27 is a leaf spring composed of an annular flat plate-shaped thin portion orthogonal to the axial direction, and is elastically deformable in the axial direction and rigid in the rotational direction. The outer end of the elastic member 27 is integrally connected to the nut portion 25, and the inner end thereof is integrally connected to the flange portion 25a.

A strain gauge is used as the displacement detecting means 29 and is attached to the surface of the elastic member 27, and the amount of fine movement is detected by detecting the amount of strain of the elastic member 27 that elastically deforms in response to the displacement. It is supposed to do.
As shown in FIGS. 4 (b) and 4 (c), the displacement detection means 29 is attached at a position where the elastic member 27 has the largest distortion,
In this illustrated example, the elastic member 27 is attached in the vicinity of the connection end to enhance the sensitivity.

The elastic member 27 may have an annular flat plate shape as shown in FIG. 5 (a) or may have a suitable hole 27a as shown in FIGS. 5 (b) and (c).

6 (a) to 6 (c) show an example of the arrangement of the minute displacement means and the elastic member.

FIG. 6A shows an example in which the elastic member 27 and the minute displacement means 28 are both formed in a ring shape and arranged concentrically.

FIG. 6B shows a rod-shaped minute displacement means 28a.
In this example, a ring-shaped elastic member 27 is used, and rod-shaped minute displacement means 28a are arranged at three positions.

In FIG. 6 (c), the rod-shaped minute displacement means 28a is used, and the elastic member 27b is used as the rod-shaped minute displacement means 2.
It is divided in the circumferential direction so as to avoid 8a.

Further, the shape of the elastic member 27 does not have to be a thin annular flat plate shape orthogonal to the axial direction as described above. For example, as shown in FIG. It is also possible to have a structure inclining in a circular shape, and FIG.
As shown in (b), a thin-walled cylindrical shape parallel to the axial direction may be used. In short, a shape that is elastically deformable in the axial direction and rigid in the circumferential direction may be selected.

In the above embodiment, the nut portion and the axially extending / contracting portion are integrally formed, but in some cases, they may be formed separately as shown in FIG.

That is, in the axial expansion / contraction part 36, the annular first and second holders 36a, 36 in which the elastic member 37 and the minute displacement means 38 such as a piezoelectric element are arranged so as to face each other in parallel.
It is interposed between b. The elastic member 37 is a leaf spring composed of an annular flat plate-like thin portion as in the embodiment shown in FIG. 4, the inner end of which is joined to the first holder 36a and the outer end of which is attached to the second holder 36b. It is joined to form an integral structure. A resistance sensor such as a strain gauge is also used as the displacement detecting means 39 and is attached to the surface of the elastic member 37.

In this embodiment, a rod-shaped member is used as the minute displacement means 38, the elastic member 37 is partially cut away, and the minute displacement means 38 is mounted in this cutout hole 37a.

The axial expansion / contraction portion 36 is assembled to the outer peripheral side of the nut portion 35, the first holder 36a is joined to the flange 35a of the nut portion 35, and the second holder 36b is attached to the table 2.

In the case of such a split type, an error occurs at the joint between the axially extending / contracting portion 36 and the nut portion 35, which requires adjustment, and the characteristics may change depending on the joint state. In this respect, in the case of the integral structure, since there is no joint portion, it is possible to obtain the characteristics as designed and is advantageous. However, the split type has an advantage that it is relatively easy to make, and it may be selected whether it is integrated or split type according to need.

The shape of the elastic member shown in FIG.
It is needless to say that the arrangement configuration of the elastic member and the minute displacement means shown in FIG. 7, the modification of the elastic member shown in FIG. 7, and the like can all be applied to this split type embodiment.

[0073]

As described above, according to the present invention, coarse feed is performed by the feed screw shaft and nut portion and fine feed is performed by the axial expansion / contraction portion, so that the resolution is high and the stroke is long. A precise positioning and fine movement feeder can be realized.

Further, since the axially extending / contracting portion is provided on the nut portion, it can be made much more compact than the conventional type of apparatus that stacks tables.

Further, unlike the conventional inchworm mechanism, the clamp does not support the axial position, but the minute displacement means and the feed screw shaft positionally support so that a large axial load can be received.
Also, since the device structure can be made low, a fine positioning fine feed device that is strong against moment load can be realized.

Furthermore, the problem of microvibration during positioning can be solved by operating the axial expansion / contraction part so as to cancel the vibration, and positioning can be completed in a short time.

On the other hand, according to the fine positioning fine movement feed system of the present invention, the fine positioning and fine movement feed can be performed quickly and reliably.

Further, if a converter for converting the fine motion control target signal output from the command device to the fine motion control device from a digital signal to an analog signal is provided, the command system for the fine motion control and the coarse motion control is provided as one command. It can be done in the device.

Further, if the fine movement feed control is performed by analog control, the command device does not require a high frequency oscillation circuit for fine movement control, the circuit structure can be simplified, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 (a) is a diagram showing a conceptual configuration of a fine positioning fine movement feeding device of the present invention, FIG. 1 (b) is a diagram showing a conceptual configuration of an axial expansion / contraction portion of FIG. 1 (a), and FIG. (c) and (d) are configuration diagrams of the axial expansion / contraction part showing an example in which a fluid pressure actuator is used as the minute displacement means.

2 (a) to 2 (e) are configuration diagrams showing various modes of displacement detecting means of an axially expanding / contracting portion of FIG.

FIG. 3 is a block diagram of a fine positioning fine movement feed system of the present invention.

FIG. 4 shows an embodiment in which the fine positioning fine movement feed device of the present invention is further embodied. FIG. 4 (a) is an overall longitudinal sectional view, and FIGS. 4 (b) and 4 (c) are same diagrams. FIG. 6 is a cross-sectional view of relevant parts for explaining an operating state of the axially stretchable part of (a).

5 (a) to 5 (c) are plan views showing various modifications of the elastic member of the axial expansion / contraction part of FIG.

6 (a) to 6 (c) are views showing various arrangement examples of the elastic member and the minute displacement means of the axially stretchable portion of FIG.

7 (a) and 7 (b) are main-portion cross-sectional views showing a modified example of the elastic member of the axially stretchable portion of FIG.

FIG. 8 shows another embodiment of the fine positioning fine movement feed device of the present invention. FIG. 8 (a) is an overall longitudinal sectional view, FIG.
(b) is a vertical cross-sectional view of the axially stretchable portion, and (c) is an enlarged cross-sectional view of essential parts showing a deformed state of the elastic member of the axially stretchable portion.

9 (a) is a schematic perspective view of a conventional feeding device, FIG.
(b) is a schematic sectional view of the inchworm mechanism shown in (a).

[Explanation of symbols]

 1 Precision Positioning Fine-motion Feeding Device 2 Table (Fed Member) 3 Feed Screw Shaft 4 Ball 5, 25, 35 Nut Part 6, 26, 36 Axial Expansion / Contraction Part 7, 27, 37 Elastic Member 8, 28, 38 Micro Displacement Means 9, 28, 38 Displacement detecting means 11 Motor (rotation driving means) 13 Command device 14 Micro displacement means driver 15 Fine motion control device 16 Digital, analog converter

Claims (13)

[Claims] 1. A nut portion which is screwed onto a feed screw shaft and moves linearly by the rotation of the feed screw shaft, is provided with an axial expanding / contracting portion which is expandable / contractible in the axial direction of the feed screw shaft with respect to the nut portion,
A fine positioning fine feed device characterized in that a fed member is attached to the axially extending / contracting portion, and coarse feed of the fed member is performed by a feed screw shaft, and fine movement is performed by the axial extending / contracting portion. 2. The axial expansion / contraction part is an elastic member that is elastically deformable in the axial direction and is rigid in the rotation direction, a minute displacement means that can be expanded / contracted in the axial direction, and a fine movement for detecting a fine movement feed amount to the nut portion. The fine positioning fine feed device according to claim 1, further comprising a feed amount detecting means. 3. The fine positioning fine feed apparatus according to claim 2, wherein the expansion / contraction amount of the fine displacement means is controlled based on the detection value detected by the fine movement feed amount detecting means. 4. The fine positioning fine movement feed device according to claim 2, wherein the fine displacement means is a means which, when a command value is given, is displaced in the axial direction in proportion to the command value. 5. The fine positioning fine movement feed device according to claim 4, wherein the fine displacement means is composed of a piezoelectric element or an electrostrictive element. 6. The fine positioning fine movement feed device according to claim 4, wherein the fine displacement means is an actuator that expands and contracts by utilizing fluid pressure. 7. The precision positioning fine movement feed device according to claim 4, wherein the fine displacement means is an actuator that expands and contracts by utilizing thermal expansion. 8. The fine positioning fine movement feed device according to claim 4, wherein the fine displacement means is an actuator using a voice coil. 9. The fine positioning fine feed device according to claim 4, wherein the fine displacement means is an actuator using a magnetostrictive element. 10. A movable table as a member to be fed is attached to the nut portion, the movable table is movably guided and held through a linear motion guide mechanism, and the feed screw shaft is rotated by a rotation driving means to perform coarse movement. Claim 1 for sending
The fine positioning fine feed device according to 2, 3, 4, 5, 6 or 7. 11. A feed screw shaft, a nut portion screwed to the feed screw shaft, an axially extending / contracting portion having a minute displacement means provided so as to be extendable / contractible in the axial direction with respect to the nut portion, and a predetermined portion. A rotation driving means for coarsely feeding the nut portion to the feed screw shaft by a predetermined stroke by rotating the feed screw shaft by a predetermined amount based on the coarse movement control target signal, and a fine movement feed amount by the axial expansion / contraction portion. A fine movement feed amount detecting means for detecting, a fine movement control device for driving and controlling the fine displacement means based on an output of the fine movement feed amount detecting means and a predetermined fine movement control target signal, and a coarse movement control target for the rotation driving means. A fine positioning fine movement feed system comprising: a command device for giving a signal to the fine displacement means to give a fine movement control target signal. 12. A coarse movement feed amount detecting means for detecting a coarse movement feed amount of a nut portion with respect to a feed screw shaft, and the rotation based on an output of the coarse movement feed amount detecting means and a predetermined coarse movement control target signal. 12. The fine positioning fine movement feed system according to claim 11, further comprising a coarse movement control device for driving and controlling the driving means. 13. A converter for converting a fine movement control target signal output from a command device to a fine movement control device from a digital signal to an analog signal is provided, and the rotation driving means is controlled by a digital signal to control the axial expansion / contraction portion. The precise positioning fine feed system according to claim 11 or 12, wherein the control is performed by an analog signal.