JPH0347803Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a slide table device that uses a static air bearing to move a movable table relative to a table guide in a non-contact manner.

BACKGROUND OF THE INVENTION In recent years, slide table devices using hydrostatic air bearings have been used for guidance in precision machine tools and measuring instruments that require high-precision guidance and positioning at submicron levels. As shown in FIGS. 3 and 4, this slide table device is provided with a rail-shaped table guide 1 held by a rectangular tube-shaped moving table 2, and the outer circumferential surface of the table guide 1 and the moving table 2
A minute bearing clearance 3 is provided between the movable table 2 and the inner peripheral surface thereof, an air supply passage 4 is provided in the longitudinal direction inside the movable table 2, and a large number of orifices 5, 5, etc. are branched from the air supply passage 4. The compressed air generated by an external compressor or the like is supplied to the air supply passage 4 of the movable table 2 through an air hose (not shown), and further from the air supply passage 4 to the orifice 5,
5 to the bearing gap 3 to create an appropriate pressure distribution, thereby forming a static pressure air bearing between the table guide 1 and the movable table 2, and applying the load of the movable table 2. There is. Then, in this loaded state, the moving table 2 is moved along the table guide 1 by an appropriate driving means such as a ball screw, and the workpiece placed on the upper surface of the moving table 2 is subjected to a predetermined processing or inspection measurement head. Perform the specified inspection and measurement work.

Problems to be Solved by the Invention In the slide table device, the movable table 2 is held in a non-contact state with respect to the table guide 1 by a static air bearing. Therefore, the moving table 2 has the characteristic of smooth movement without stick slip. However, since there is no damping ability against the movement of the moving table 2, there is a problem in that control oscillations are likely to occur when positioning is performed. Furthermore, when moving the moving table 2, if the line of action of the driving means and the center of gravity of the moving table 2 are even slightly misaligned, vibrations will occur in the moving table 2 in the yawing direction, and the vibrations will not be damped easily. When used as a positioning device, there was a drawback that positioning accuracy was impaired due to vibration in the yawing direction. Therefore, to solve the former problem, it was necessary to provide a damper effect to the driving means of the moving table 2 by inserting a phase advance circuit into its control circuit or by feeding back the speed signal. Moreover, there was no very effective means for dealing with the latter problem.

Therefore, instead of providing a damper effect to the driving means of the moving table, a viscous liquid such as grease oil or silicone oil is interposed between the moving table and the base parallel to the moving direction of the moving table. A sliding table device that dampens table vibrations has already been proposed in Japanese Patent Application Laid-Open No. 1363/1983, but this structure has the disadvantage that the liquid evaporates and scatters, contaminating the surrounding area. It cannot be used in equipment that is extremely sensitive to oil, such as laser cutting machines.

Means for Solving the Problems This invention provides a solution by interposing a viscous fluid between a movable table and a fluid support plate that is disposed facing each other with a slight gap below the movable table. When the movable table moves, a damper effect is applied to the movement of the movable table by the viscous resistance of the fluid, and the vibration of the movable table is absorbed by this damper effect.

To explain in detail with reference to the drawings, in FIGS. 1 and 2, reference numeral 11 is a table guide formed of a long bar member with a rectangular cross section. It is fixedly installed on 13. 14 is a rectangular tube-shaped movable table that slidably holds the table guide 11;
A table guide 11 extends through the movable table 14. A small bearing clearance 15 is provided between the inner circumferential surface of the movable table 14 and the outer circumferential surface of the table guide 11, and a plurality of air supply passages 16 are provided inside in the longitudinal direction, and branched from the air supply passage 16. A large number of orifices 17 open on the inner circumferential surface,
17... is provided, and the compressed air supplied to the air supply passage 16 is ejected into the bearing gap 15 through the orifices 17, 17..., forming a uniform pressure distribution in the bearing gap 15, and thereby operating the static pressure air bearing. It consists of Further, the movable table 14 is provided with a rectangular land groove 18 on the lower surface, and a lattice-shaped groove 19 is provided inside the land groove 18, and a viscous fluid 20, such as grease, silicone oil, etc., is provided in the lattice groove 19. is filled with. Reference numeral 21 denotes a flat fluid bearing plate provided below the table guide 11 in parallel to the moving direction of the movable table 14. Its upper surface faces the lower surface of the movable table 14 with a slight gap 22, and the lattice of the movable table 14 is Fluid 2 filled in groove 19
0, so that it is in contact with the moving table 14 via the fluid 20. This fluid bearing plate 21 is provided with adjustment bolts 23 and fixing bolts 24 at the four corners, and by adjusting the height of the four corners with the adjustment bolts 23, the parallelism with the movable table 14 can be adjusted. , and is fixed to the base 13 with fixing bolts 24. The land grooves 18 provided on the outside of the lattice grooves 19 of the moving table 14 prevent the fluid 20 that has protruded from the lattice grooves 19 from flowing out toward both ends of the gap 22. The distance H is set to be larger than the stroke of the moving table 14, so that even if the moving table 14 moves the entire stroke, the surface of the fluid support plate 21 that corresponds to the land groove 18 and to which the fluid 20 is attached, It is designed so that it is not exposed from both ends of the moving table 14. In addition, the movable table 14 has a plurality of replenishment holes 25 that open into the lattice grooves 19 from the side, and these holes 25 allow fluid 20 to be supplied into the lattice grooves 19 without removing the movable table 14 from the table guide 11. It is now possible to replenish the

Action: Move table 14 along table guide 11
When the moving table 14 and fluid support plate 2 move,
1 moves relative to each other, the fluid 20 interposed in the gap 22 between the moving table 14 and the fluid support plate 21
A damper effect on the movement of the moving table 14 is obtained due to the viscous resistance of
For example, even if vibration occurs in the yawing direction, this vibration is immediately damped. At this time, a slight gap 22 is provided between the movable table 14 and the fluid support plate 21, and since only the viscous fluid 20 is present in the gap 22, the table guide Even if there is an error in the parallelism between the table 11 and the fluid bearing plate 21 or the surface area of the fluid bearing plate 21 is somewhat poor, the gap 22 and the fluid 20 will absorb it, so it will not affect the straightness of the moving table 14. .

The height of the four corners of the support plate 21 can be adjusted using adjustment bolts 23 and fixing bolts 24, so in order to obtain the desired damper effect, the gap 22 between the support plate 21 and the slide table 14 can be finely adjusted, and the height of the slide table 14 can be adjusted. Parallelism with the bottom surface can be adjusted.

In addition, a support plate 2 is attached to the bottom surface of the slide table 14.
1, the gap 22 that accommodates the fluid 20 extends horizontally, so that the fluid can be held uniformly and reliably in the length and width of the gap 22. Furthermore, the land groove 18 Coupled with the presence of , leakage of fluid 20 is effectively prevented.

Effects of the invention This invention provides a slide table device that uses a static pressure air bearing to move a movable table with respect to a table guide in a non-contact state.
A lattice-shaped groove is provided on the lower surface of the movable table, a viscous fluid is filled in the lattice groove, and the fluid is supported by a fluid support plate disposed opposite to the lower surface of the movable table with a slight gap. Since a viscous fluid is interposed between the movable table and the fluid support plate, when the movable table is moved, a damper effect is produced due to the viscous resistance of the viscous fluid interposed between the movable table and the fluid support plate. The vibration of the moving table can be absorbed by this damper effect, and when the slide table device of this invention is used as a positioning device, for example,
Highly accurate positioning can be performed. Furthermore, since the lattice grooves of the moving table are surrounded by rectangular land grooves whose distance to both ends of the moving table is larger than the entire stroke of the moving table, fluid protruding from the lattice grooves is less likely to flow out. Even when the movable table moves the full stroke, the surface that corresponds to the land groove of the fluid support plate and to which the fluid adheres is not exposed from both ends of the movable table, so the fluid is extremely unlikely to sway into the atmosphere. The amount of evaporation of the fluid is small, and the fluid does not contaminate the surroundings. Therefore, it can be used satisfactorily even in equipment that is extremely sensitive to oil, such as a laser cutting machine for optical disks.

Further, according to this invention, since the support plate is provided on the lower surface of the slide table, yawing can be particularly prevented reliably.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view of an embodiment of the slide table device of this invention, Fig. 2 is a view of the movable table seen from below, Fig. 3 is an oblique view of the conventional slide table device, and Fig. 4 is its view. FIG. 1... Table guide, 14... Moving table, 15... Bearing clearance, 18... Land groove, 1
9... Lattice groove, 20... Viscous fluid, 21
...Fluid support plate, 22...Gap.

Claims (1)

[Scope of utility model registration request] The table guide is held by the movable table, and a small bearing gap is created between the movable table and the table guide, and compressed air is supplied to this bearing gap to form a uniform pressure distribution to create a static air bearing. In the slide table device configured to move the movable table in a non-contact state with respect to the table guide, the lower surface of the movable table has a lattice-shaped groove and a rectangular land groove surrounding the lattice groove. The lattice grooves are filled with a viscous fluid, and this fluid is supported by a fluid support plate that is placed opposite the lower surface of the moving table with a slight gap between the moving table and the fluid supporting plate. A slide characterized in that a viscous fluid is interposed between the slide and the plate, and the lattice groove is surrounded by a rectangular land groove whose distance to both ends of the moving table is larger than the entire stroke of the moving table. table equipment.