JPS58160034A - Composite guide system for machine tool - Google Patents

Abstract

PURPOSE:To make it possible to improve the precision of movement of a moving substance and the precision of positioning thereof by a method wherein in the slide guide surfaces of the machine tool, some of the guide surfaces are formed as dynamic pressure slide guide surfaces and the others are formed as pneumatic static pressure slide guide surfaces. CONSTITUTION:The dynamic slide guide surfaces 201-206 and the static pressure slide guide surfaces 207 and 208 are formed on a grinder shaft housing 101 and a static pressure guide plate 105, respectively, of a plane surface grinder. When compressed air supplied from a plurality of air supply ports 303 in the static pressure guide surfaces via a pressure adjust valve thrusts the moving substance 101 against the dynamic pressure slide guide surfaces 205 and 206 and the gap in the static pressure guide section change due to the inclination of the moving substance, the pressure at that section increaes to generate a force of restitution. Thus, it is possible to control the partial abrasion of the slide surfaces and to improve the precision of movement of the moving substance and the precision of positioning thereof. Further, since air is used as the operating fluid no collection of the operating fluid is required and the device is simplified.

Description

Detailed Description of the Invention The present invention provides a guideway for a machine tool in which one of a pair of opposing sliding guideways is a hydrostatic slideway and the other is an aerostatic guideway, and the hydrostatic slideway is the only one. The aerostatic pressure guide surface acts on the dynamic pressure slide guide surface to press the moving body with a constant pressure, and as a result, the surface pressure distribution within the dynamic pressure slide guide surface is made uniform, and the moving body's The purpose is to regulate the posture and allow linear movement.

In the conventional vertical dynamic pressure sliding guide system, an external moment force acts on the moving body due to the geometric relationship between the drive center of the drive unit such as the feed screw, the center of gravity of the moving body, and the position where the external force acts.
The moving body tilts with respect to the guide surface, creating uneven surface pressure within the guide surface, causing partial uneven contact between the moving body and the guide surface, and in extreme cases, metal-to-metal contact, promoting wear. do. Further, in a conventional pair of sliding guide surfaces facing each other, there are two motion references for the moving body, and therefore, depending on an external force acting on the moving body, one of the surfaces becomes the motion reference. Therefore, unstable behavior of the moving body occurs, which becomes an obstacle to precise positioning.

The double-sided static pressure guide system has a smaller frictional force than the dynamic pressure slide guide system, and phenomena such as uneven contact are less likely to occur.

However, since the frictional force is small, no distribution effect due to friction can be expected. Furthermore, most of the external force applied to the moving body is received by the drive system, causing the moving body to be unnecessarily displaced and positioning accuracy to be reduced.

In addition, in consideration of these points, the composite guide system, in which one side is a hydrodynamic slide guide surface and the other is a hydrostatic pressure guide surface, uses the pressure generated on the hydrostatic pressure guide surface to press the moving body against the dynamic pressure peri-guide surface. As a result, the hydrodynamic slide guide surface is used as the only motion reference, and the surface pressure distribution on the hydrodynamic slide guide surface is made uniform, so unstable behavior is suppressed. Furthermore, the frictional force generated in the dynamic pressure sliding guide provides vibration damping properties in the driving direction. However, since a hydrostatic guideway is used,
Oil recovery is required, which complicates the equipment.

In consideration of these points, the present invention has a pair of opposing guide surfaces, one of which is a dynamic pressure slide guide surface and the other an aerostatic pressure guide surface, and the hydrodynamic slide guide surface is used as the only motion reference. , to equalize the surface pressure distribution on the hydrodynamic sliding guideway,
It has vibration damping properties in the driving direction, and since the air, which is the working fluid of the static pressure guide, is released into the atmosphere, there is no need to recover it, which simplifies the device.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a vertical guide surface of a surface grinder according to the present invention. 101 is a grinding wheel shaft housing, 102.
103 is a column, 104 is a feed screw, and 105 is a static pressure guide plate. The grinding wheel shaft housing 101 has a column 102.
103 and moves up and down by a feed screw 104.

The static pressure guide plate 105 is coupled to the grindstone shaft housing 101 with bolts. In this embodiment, the present invention is applied only in the direction of arrow A. In the direction of arrow B, a dynamic pressure sliding guide system is used. This is because the direction of arrow B is almost symmetrical with respect to the feed screw, and it can be assumed that the drive center and the center of gravity of the moving body are geometrically coincident.The present invention is also applied in the direction of arrow B. This will give you even better movement accuracy.

FIG. 2 shows a guide surface and is a plan view of FIG. 1 viewed from above. 101 is a grinding wheel shaft housing, 102 and 103 are columns, 104 is a feed screw, 105 is a static pressure guide plate, 201
206 to 206 are dynamic pressure slide guide surfaces, and 207 and 208 are static pressure guide portions. In this embodiment, the present invention is applied only to the front-rear direction of the grindstone shaft housing, that is, the direction of arrow A in FIG.

A dynamic pressure slide guide surface 205 and a static pressure guide section 207 are combined, and a dynamic pressure slide guide surface 206 and a static pressure guide section 208 are combined.

FIG. 3 is a front view showing the static pressure guide portion of the static pressure guide plate as seen from the direction of arrow C in FIG. 2. FIG. 301 and 302 are static pressure guide parts, and 303 is a plurality of air supply ports. Supply port 30
The air supplied from 301 and 302 passes through the static pressure guide sections 301 and 302 at a reduced pressure and is discharged into the atmosphere.

FIG. 4 is a cross-sectional view of the static pressure guide plate 105 of FIG. 3 taken along line DD. 105 is a static pressure guide plate, 401 is an air supply source, 402 is a manifold, and 403 is a throttle. Air is supplied from an air supply source 401 to a manifold 402 and to an aperture 40.
3 to reach the guide surface. In addition, the manifold 402
It is also possible to insert a pressure regulating valve or a pressure control type servo valve between the aperture 403 and the throttle 403 to adjust the pressure in each pocket.

The static pressure guide presses the moving body against the periphery guide surface that applies dynamic pressure, and when the moving body tilts and the gap in the static pressure guide changes, the pressure in the area where the gap narrows rises and the gap returns to its original state. Provides resilience.

Although the explanation has been given by taking the vertical guidance method as an example, the same applies to the horizontal guidance method. In the hydrodynamic slide guide method, the lateral movement standard is the same as in the vertical dynamic pressure slide guide method described above.
Because there are two of them, the moving body exhibits unstable behavior, resulting in decreased motion accuracy and positioning accuracy. Further, even with the static pressure guide method, as described above, there are problems with the ability to allocate the driving direction and the feeding system supporting the driving force. By applying the present invention, the motion accuracy and positioning accuracy of the moving body can be improved, and the vibration damping performance in the driving direction can be improved.

As described above, in the present invention, three sides of a pair of opposing sliding guide surfaces are dynamic pressure slide guide surfaces and the other is an aerostatic pressure guide surface, and the hydrostatic pressure slide guide surface is used as the only motion reference. The surface acts to press the moving body against the hydrodynamic slide guide surface with a constant pressure, and as a result, the surface pressure distribution within the hydrodynamic slide guide surface is made uniform, so the posture of the moving body is regulated and linear motion is prevented. do. Further, according to the present invention, it is possible to suppress partial wear of the sliding surface and provide the ability to distribute vibration in the driving direction.

Therefore, the movement accuracy and positioning accuracy of the moving body can be improved. Furthermore, since air, which is the working fluid of the static pressure guide, is released into the atmosphere, there is no need to recover it, which simplifies the device.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a perspective view of a vertical guide surface of a surface grinder. FIG. 2 is a plan view showing the arrangement of sliding surfaces when viewed from above in FIG. 1. FIG. 3 is a front view of the static pressure guide plate seen from the direction of arrow C in FIG. FIG. 4 is a sectional view of the static pressure guide plate taken along line DD in FIG. 3. 101...2-shaft grindstone...Using, 102.103...
... Column, 104 ... Feed screw, 105 ... Static pressure guide plate, 201 to 206 ... Dynamic pressure slide guide surface, 20
7.208... Static pressure guide surface, 303... Air supply port, 401... Air supply source, 402... Manifold, 403... Throttle. Figure 4, z05

Claims (1)

[Claims] A sliding guide surface for a machine tool having a pair of opposing sliding guide surfaces is characterized in that one of the sliding guide surfaces is a hydrodynamic slide guide surface and the other is an aerostatic pressure guide surface. Complex guidance system for machine tools.