JPS61239307A - Positioning device - Google Patents

Abstract

PURPOSE:To realize high-speed and high-accuracy positioning operations with a linear actuator equipped with a static-pressure pneumatic guide as a guiding mechanism and linear DC motor as a driving means, by adjacently providing the slider section of the guiding mechanism and coil section of the linear DC motor and uniting them to one body. CONSTITUTION:A static-pressure pneumatic guide 1 is composed of a rectangular static-pressure guide 3 and static-pressure slider 4, which are assembled to have a clearance of several tens mm between them and high-pressure air is supplied to the clearance from the static-pressure slider 4. On the other hand, a linear motor is composed of an outer yoke 6 provided with permanent magnets 5, which are fixed in such a way that their magnetic poles are alternately faced to each other in the direction of length, center yoke 7 positioned to the central part, and coil 8 which is installed to the clearance between the outer yoke 6 and center yoke 7 in such a way that the coil 8 can surround the center yoke 7. Since the static-pressure slider 4 and the coil 8 are united to one body in this invention, all the movable sections are completely separated from the static sections and the former is not contacted with the latter. Therefore, a driving and guiding mechanism which is free from frictional force and backlash and hardly causes yawing and pitching can be obtained.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a positioning device, and particularly to a positioning device that uses a static pressure air guide, a linear DC motor, a movable part actuator, a static pressure air guide, a linear motor, and a linear scale as a drive mechanism. The present invention relates to an arrangement structure suitable for high-speed, high-precision positioning, in particular, by making the movable parts completely non-contact, and by arranging the above-mentioned main components adjacent to each other.

[Background of the invention]

As described in Japanese Patent Laid-Open No. 57-1491 [79], a conventional positioning device rt uses a linear motor with no sliding parts for drive and a non-contact linear scale for position detection. The linear guide is configured using a rolling contact linear guide. In addition, as another device, a non-contact static pressure air guide is used in the drive part,
Some use a feed screw with roller contact and a rotary DC motor.

However, the above-mentioned apparatus has the following problems in order to perform high-speed, high-precision positioning.

The linear guide of the above device is a rolling contact, and pack lash and friction force exist even if the value is small.Also, in order to eliminate backlash, there is a method of applying preload to the linear guide, but the friction is even larger. Become. moreover,
The X-axis near guides are placed at both ends of the device, and it is impossible to perfectly match the frictional forces between the two. For this reason, yawing may occur while the vehicle is running, and vibrations may remain even after the vehicle has stopped. On the other hand, in the driving method using a rolling contact feed screw, a preload is applied to the feed screw nut in order to accurately transmit the motor torque and rotational position. Therefore, backlash will be reduced, but
Frictional force is always present.As mentioned above, even in rolling contact where frictional force is said to be small, in structures with sliding parts, as long as frictional force and backlash exist, high-precision positioning on the order of mm is extremely difficult. Have difficulty. Furthermore, even if advanced know-how is used to achieve this, if the system is operated for a long period of time, the frictional force and amount of backlash will change due to heat generation and wear of the sliding parts, resulting in a decline in initial performance.

Note that in order to reduce frictional force and backlash from the beginning, it is also possible to lower the preload.

However, according to this, the linear guide has poor running straightness, and the feed screw has poor accurate 100-line variation in rotation angle, and therefore Mm order positioning is difficult.

Therefore, a combination of a linear DC motor and a static air guide or a near actuator are suitable for positioning on the order of mm, but even in this case, if the positions are separated by 4 degrees, yawing or pitching may occur.

Furthermore, although the fluid is oil, the X and Y table d, which uses static pressure guidance, has been commercialized as shown in the KK Fujikoshi catalog, but it is driven by a combination of a rotary motor and a ball screw. 0 In this method, the guiding has zero frictional force, but since the nut of the ball screw is in rolling contact, there is friction and pack lash in this part.
Therefore, similar to the above, submicron positioning at high speed is extremely difficult.

In addition, the structure in which cylindrical static pressure air guides are arranged in parallel is described in Precision Machinery, P47, Volume 50, No. 5, 19g.
4, Ota's "Near Mosque Bearing"
However, there is no mention of an orthogonal positioning device having a table-type structure and having a gate-type structure in combination with drive and position detection.

Further, all of the guide shafts described above have solid rectangular or circular cross sections, but there is still room for improvement in terms of improving the rigidity of the guide shafts and saving material.

[Purpose of the invention]

The present invention was invented in view of the above, and its purpose is to
By integrating the slider part of the static pressure air guide, which is the guiding mechanism, and the coil part of the linear DC motor, which is the driving mechanism, it is a non-contact system that enables high-speed, high-precision positioning. The object of the present invention is to provide an IJ near actuator of the present invention, and to provide an orthogonal positioning device having a portal structure using the above drive mechanism. Furthermore, it is an object of the present invention to provide the above-mentioned device which can increase the specific number of transverse motions of the guide shaft and reduce the vibration of the guide shaft during running and stopping. If there is Pack-Lassier friction force in the sliding part or the drive transmission part, it is extremely difficult to perform high-speed and highly accurate positioning. Further, even if the performance is initially achieved, it is practically impossible because frictional force and the like change over time. Therefore, since the movable part is non-contact, there is no friction, and by using a static pressure air guide and an IJ near DC motor, the movable part and the stationary part are completely non-contact.

[Embodiments of the invention]

An embodiment of the present invention will be explained with reference to FIG. FIG. 2 shows a cross-sectional structure in which a rectangular cross-section static pressure air guide 1 and a linear DC motor 2 are integrated in parallel. The static pressure air guide 1 consists of a rectangular static pressure guide 8 and a static pressure slider 4, which are assembled with a gap of several tens of millimeters, and although not shown, high pressure air is passed through separate piping. It is supplied to the gap from the static pressure slider 4.

On the other hand, a linear motor has an outer yoke 6 which is attached to a permanent magnet 5 with magnetic poles fixed alternately and facing each other in the longitudinal direction, and a center yoke 7 is disposed in the center.
A coil 8 is arranged in the gap so as to go around the center yoke 7. The electromagnetic force generated by passing a current through the coil 8 causes the coil 8 to move in the longitudinal direction.

By integrating the static pressure slider 4 and the coil 8 as shown in FIG. 2, all movable parts are separated from the stationary part and are completely out of contact with each other. Moreover, the five adjacent parts are integrated as close as possible.

Another embodiment of the present invention will be described with reference to FIG.

Two circular cross-section static pressure air guides 9 and a linear motor 10 are integrated in parallel, and in particular, the linear motor U2f [
It is arranged symmetrically in the center between the 61 hydrostatic air guides. Its cross-sectional structure is shown in FIG.

The circular cross-section static pressure air guide 9 includes a cylindrical static pressure guide 11,
It consists of a static pressure slider 12 and a plate 18 that connects the two static pressure sliders. The static pressure slider 12 has a ratio of several tens of #m to the static pressure guide 11 at 1:4! are mated up to
High pressure air is supplied from the static pressure slider to the Gogogo, and they are not in contact with each other.

On the other hand, the structure and function of the linear DC motor 10 are exactly the same as those shown in FIG. However, is the center of the coil 14 the center line of the 2@ static pressure guide 13? The linear DC motor 10 is completely self-repaired so that it is located within the containing plane. By fixing and integrating the coil 14 with the plate 18, all movable parts are separated from the stationary part, making them completely non-contact.

As explained in the above two embodiments, by integrating the movable parts of the static pressure air guide and the linear DC motor adjacently, the drive and It becomes a guidance mechanism. In particular, in the structure shown in FIG. 3, since the point where the driving force of the linear DC motor is generated is at the center of the left and right sides and within the static pressure slide plane, no yawing or pitching occurs during running. Therefore, it is possible to achieve high-speed positioning on the order of 77 m, and since the characteristics do not change over time, the reliability of the positioning unit employing the structure of the present invention is sufficiently high.

Next, another embodiment of the above-mentioned position (d determining device) using the drive mechanism will be explained with reference to FIG. , are fixed to the upper surface of the projections 104 at the four corners of the base 108.

The fixing structure is such that both ends of the guide shaft 102, which has a cylindrical cross section, are processed to be parallel and are directly fixed to the base 108, as shown in FIG. 6, which is shown as a view A in FIG. The two Annai shafts 102 are fixed mt and slide horizontally, and their parallelism is adjusted to several micrometers over the entire stroke. Furthermore, high-pressure air is supplied from the inner surface of the static pressure slider 105, and the gap with the guide shaft 102 is approximately 10 micrometers and 7 meters over the entire surface. Therefore, two static pressure sliders 105 are arranged to move in parallel on both sides of the base 108, and a working space is provided between them.

Then, configure the X-axis static pressure air guide, linear motor, and linear scale layout as shown in Figure 5B! When shown as a diagram L, as shown in FIG. 7, they are all arranged adjacent to each other in an integral structure. In FIG. 4, the X-axis static pressure slider 10
5, a bobbin 107 of a linear motor 106,
A detection head 109 of a linear scale 108 is fixed. moreover.

A permanent magnet is arranged in the outer yoke 110, and a magnetic enclosure is formed between the steel center yoke 111.
A bobbin 107 is placed in the magnetic field between them. Furthermore, an optical sensor is built into the detection head 109 in a non-contact manner, facing the reflective optical scale 112 . In this way, the movable parts in the %X-axis direction are all separated from the stationary part and are completely non-contact.

On the other hand, on the Y-axis, as shown in FIG.
The entire body moves in the X-axis direction.

The guide shaft 17 of the Y axis is the 8th guide shaft shown as C recovery in FIG.
As shown in the figure, two pieces are fixed in parallel above and below the linear motor 115, and like the X-axis guide shaft 102, they slide on the contact surface with the joint plate 118 to adjust the parallelism of the two pieces. It has been adjusted.

If the arrangement structure of the Y-axis static pressure air guide, linear motor, and linear scale is shown as a view D in FIG.
As shown, they are all placed next to each other in a monolithic structure. In FIG. 9, a %Y-axis solinear motor bobbin 119 & a Y-axis linear scale detection head 120 are fixed to the Y-axis static pressure slider 118, and their functions are exactly the same as those of the X-axis. All Y-axis movable parts are non-contact.

In such an orthogonal positioning device having a portal structure, the electromagnetic force generated by *m flowing to the bobbin 107, 119 of the linear motor 106, 115 moves the X-axis static pressure slider 105 in the X- and Y-axis directions. Pressure Static Pressure 1
18 is driven. And linear scale 108,
At step 116, two positions are detected and the movement is performed until the two positions match the command value. I7 Since the near scale is adjacent to the static pressure guide, the influence of errors due to picking and rolling is reduced, and the movement of the movable part follows the static pressure air guides 101 and 114 on the Y axis. Since the part and the stationary part are completely non-contact, there is no backlash or frictional force, and therefore positioning can be performed to the detection accuracy of a linear scale. Also, since yawing vibration caused by fluctuations in friction does not occur, the Residual vibration can also be reduced, and therefore high-speed, high-precision positioning can be achieved. Moreover, since it is non-contact, there is almost no change in the percentage of sliding parts over time.
A highly reliable positioning device without performance deterioration can be achieved.

Furthermore, in the positioning device shown in FIG. 5, the cylindrical section guide shafts 102, 117 are moved to
As shown in Fig. 11, when hollow shafts 21 and 22 are used,
The natural frequency in the lateral direction is 1 + (di/do)”
rise twice. Here, 1 is the inner diameter and do is the outer diameter. At this time, the deflection will increase by 1/(1('i/do)", but if there is enough deflection, it is possible to use a hollow shaft. In this case, the hollow shafts 121 and 122 Cylindrical blocks 1 as shown in Fig. 12 are used to support both ends.
There is a fixing method in which 28 is fitted with a φ fit, or a fixing method is via a play (124t) as shown in FIG.

By making the guide shaft central in this way and increasing the natural frequency, the possibility of being excited by the control device can be reduced, and therefore the adverse effects on the aforementioned yawing vibration etc. can be reduced. Therefore, there is little residual vibration, and high-speed positioning becomes easy.

〔Effect of the invention〕

As explained above, according to the present invention, since the movable part and the stationary part are completely non-contact, there is no friction or backlash in the sliding part or the drive transmission part, and therefore there is almost no residual vibration, resulting in high-speed movement. It is also possible to perform positioning on the μm order. Furthermore, since there is no aging, high speed,
The performance of high-precision positioning does not deteriorate over a long period of time.Furthermore, the natural frequency of the guide shaft can be made higher, making it less likely to be excited, thus making the device low-vibration. , materials can be saved.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an actuator used in a positioning device showing one embodiment of the present invention, FIG. 2 is a cross-sectional view of FIG. 1, and FIG. 8 is a perspective view of an actuator showing another embodiment of the invention. FIG. 4 shows a cross-sectional view of FIG. Figure 5 is a structural diagram of a positioning device showing another embodiment, Figures 6, 7, and 8.
9 are views in the direction of the A%B, C, and D arrows in FIG. 5, respectively, and FIGS. 10 and 11 show other embodiments, respectively, and views in the direction of the B and D arrows in FIG. corresponds to Figures 12 and 18 are the first
FIG. 2 is a diagram showing a fixing structure of the guide shaft shown in FIG. 1.9... Static pressure discussion guide 2.10... Linear DC motor 3.11... Static pressure guide 4.12... Static pressure slider 5... Permanent magnet 6... Outer yoke 7...Center yoke 8.14...Coil
13...Plate 101, 114...Static pressure air guide 102.117...Guide shaft 10B...Base 104...Protrusion 105,! 18...Static pressure slider 106°115...Linear motor 7.119
...Bobbin 108.116...Linear scale
109.120...Detection head 110...Outer yoke 111...Center yoke 112...Optical scale 11B...Join play) 121,1
22... Guide hollow transport 128... Cylindrical block 12
4... Plate Kyo 1 four rods 2i rod 5m tzl 1z+

Claims (1)

[Claims] 1. A linear actuator equipped with a static pressure air guide as a guide mechanism and a linear DC motor as a drive means,
A positioning device using a non-contact linear actuator, characterized in that the static pressure slider part of the static pressure air guide and the coil part of the linear DC motor are integrated adjacently, and all movable parts are made non-contact. 2. Arrange two linear guides in parallel on both sides of the base, drive the slider part of the linear guide, detect the position, set these as the X axis, and further move the two parallel sliders mentioned above to the
This orthogonal positioning device connects the slider with a linear guide perpendicular to the axis, drives the slider, detects the position, and uses this as the Y axis.The guide is a non-contact type static pressure air guide, the drive is a linear motor, A non-contact optical linear scale is used for position detection, the movable part and the stationary part are completely non-contact, and the static air guide, linear motor, and linear scale are arranged in parallel and adjacent to form an integrated structure. An orthogonal positioning device with a gate-shaped structure. 3. An orthogonal positioning device having a portal structure according to claim 2, wherein the guide shafts of the cylindrical X and Y-axis static pressure air guides are hollow.