JPS60108240A - Guide device of heavy weight movable bench - Google Patents

Abstract

PURPOSE:To increase dynamic rigidity of the captioned bench in the feed direction thereof by supporting the weight of the bench with respect to a pair of horizontal support surfaces by a static pressure bearing, and employing a narrow guide of a dynamic slide surface of a transversal guide surface with respect to a feed screw axis as a guide in the feed screw direction. CONSTITUTION:Horizontal support surfaces 11, 12 serving to support the weight of a table and transversal guide surfaces 13, 14 are horizontally symmetrically with respect to a center of a feed screw 19, and the table 15 is prevented from meandering. Pressure fluid is supplied into a static pocket 17 on the lower surface of the table 15 via restriction resistance controlled by a variable throttle valve 18. Hereby, said pocket allows the table 15 to float to a state without metal contact and supports it. Accordingly, even if a heavy weight work is placed on the table, sliding resistance of the table 15 becomes very small and a weight change acting on the table 15 results in a change of a gap between the guide surfaces 13, 14. This causes a pressure change in the pocket 17, so that the variable throttle valve 18 is controlled to compensate for the gap change, thereby enabling a high rigidity guide work to be effected.

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a guide device for guiding a heavy movable platform of a large machine tool or the like.

<Prior art> Guideways for large machine tools such as double-column machining centers are shown in Figure 1 in order to reduce the load on the drive system since the table 1 and the workpiece 2 placed on the table are heavy. As shown, both the weight support surface 3 and the narrow guide 4 employ static pressure guide surfaces. However, since the friction coefficient of the static pressure guide surface is extremely low, there is a problem in that the dynamic rigidity in the feeding direction is low and vibrations are likely to occur.

In addition, since pressure fluid is supplied to the static pressure pocket 5 through the fixed throttle 6, the flying height changes greatly due to fluctuations in the weight of the workpiece placed on the table l, making it difficult to increase the rigidity. Furthermore, since the narrow guide 4 is disposed off-centered with respect to the feed screw 7, a moment is generated in the table 1, which causes the table 1 to meander easily.

<Objective of the Invention> Therefore, an object of the present invention is to prevent the occurrence of vibration by increasing the dynamic rigidity in the feeding direction without increasing the load on the drive system even when the weight of the table increases.

Still another object is to eliminate the moment of the narrow guide and the feed drive unit, to prevent the table from meandering, and to eliminate fluctuations in the flying height due to fluctuations in the weight of the workpiece.

<Configuration of the Invention> The characteristic configuration of the present invention is that a pair of horizontal support surfaces that perform a weight-supporting action are supported by a hydrostatic bearing, and as a guide in the feed screw direction, a pair of horizontal support surfaces are supported symmetrically with respect to the feed screw axis. A narrow guide with a vertical surface that forms a direction guide surface and applies dynamic pressure, and the dynamic rigidity in the feeding direction is increased by applying frictional force on the guide surface parallel to the direction of gravity that is unaffected by the table weight. It is.

<Example> Embodiments of the present invention will be described below based on the drawings.

In Fig. 2, 10 is a horizontal support surface formed on the top of the bed, 11. 12 is a horizontal support surface that acts as a weight support,
3.14 is a lateral guide surface that acts as a lateral guide; in front of this lateral guide surface 13, 144 is a horizontal support surface 11.
12, and the guide surface is formed in a direction perpendicular to the plane of the paper. IEI YonokXIL support surface 11, 1.2
and lateral guide surfaces 13,1. A plurality of static pressure pockets 17 are formed on the lower surface of the H-trowel slidingly guided table, and each static pressure pocket 17 has a variable throttle whose throttle resistance is adjusted in response to the pocket pressure. valve 18
are set up for each. As shown in FIG. 4, the variable throttle valve 18 includes a diaphragm 21 and a pair of valve housings 22 and 23 that connect the diaphragm 21.
Seat part ItA2 arranged on one side of the diaphragm 21
4 and a spring 25 disposed on the other side. A nozzle 26 opens in the center of a pressure chamber 22a formed by the valve housing 22 and the diaphragm 21.
The sheet member 24 is pressed against the opening end surface of this nozzle 26 to perform a restricting action. In the pressure chamber 22a around the sheet member 24, the fluid after being squeezed and passed through the static pressure pocket 17 is introduced (
Passage 27 is open. Atmospheric pressure is introduced into a chamber 23a formed by the other valve housing 23 and the diaphragm 21, and a pressing force adjusting means 2 of a spring 25 that presses the diaphragm 21 is provided on the valve housing 23 side.
8 is provided.

Threaded portion 29 carved into the upper protrusion of the valve housing 23
The screw member 30 is connected to a sliding member 32 fitted into the inner hole 31 of the protruding part by a bolt 33, and by adjusting the rotation of the screw member 30, the sliding member 32 is moved up and down, and the spring Adjust the pressing force of 25 and press the sheet member 2.
4 and the nozzle 26 can be arbitrarily set, and the flying height and throttle valve characteristics can be adjusted.

The diaphragm 21 is displaced by the fluid pressing force generated on the pressure chamber 22a side with respect to the constant pressing force of the spring 25, adjusting the gap between the sheet member 24 and the nozzle opening end face, and changing the throttling resistance. That is, when the pressure in the static pressure pocket 17 increases due to a decrease in the gap around the static pressure pocket as the load increases, the diaphragm 21 is displaced in a direction that compresses the spring 25, and the gap between the sheet member 24 and the nozzle opening end face increases. , the throttling resistance is reduced and the amount of flow into the pressure chamber 22a is increased. At the same time, the pressure in the static pressure pocket 17 increases, increasing the static pressure supporting force and compensating for changes in the fluid outflow gap around the static pressure pocket 17 due to load fluctuations.

On the other hand, as the load decreases, the gap around the static pressure pocket increases, and when the pocket pressure decreases, the diaphragm 21 restores itself, narrowing the gap between the sheet members 24 and increasing the throttling resistance, thereby increasing the flow rate into the pressure chamber 22a. , and the pressure in the static pressure pocket 17 is further reduced to compensate for the gap change.

A supply boat 35 communicating with the nozzle 26 of the variable throttle valve 18 is connected to a pressure fluid supply source 39 via a supply pressure adjusting means 36 . This supply pressure adjustment means 36 is
- For example, it is composed of a fixed throttle 37 and a variable throttle 38 provided in the drain passage, and is provided in common to a set of four variable throttle valves 18. Since the supply pressure adjusting means 36 divides the table support points into four systems, it is possible to correct one rotation of the table by adjusting the pressure for each system.

A wedge-shaped member 40 and a parallel member 41 are interposed between the lateral guide surface 13, 14 and a guide member 15a protruding from the lower surface of the table 15. At the end of the wedge-shaped member 40, as shown in FIGS. 6, 7, and 8, a tension bolt 43 is inserted into a bracket 42 fixed to the table 15 and screwed into the wedge-shaped member 40, and a tension bolt 43 is screwed into the bracket 42. A push bolt 44 whose mating end surfaces abut is provided, and the wedge-shaped member 40
It serves as a longitudinal position adjustment mechanism. By adjusting the position of the wedge-shaped member 40, the guide surface 13.14 and the guide member 1
The gap between the parts 52 is adjusted, and a predetermined surface pressure is applied to the sliding surface to provide an appropriate frictional force. This frictional force is not affected by the weight acting on the table 15 at all because the lateral guide surfaces 13 and 14 are formed parallel to the direction of gravity, and a constant frictional force is always applied, causing vibrations in the feeding direction. Stability against is maintained.

In addition, horizontal support surfaces 11 and 12 serve to support the weight of the table.
Since the lateral guide surfaces 13 and 14 are provided symmetrically with respect to the center of the feed screw 19, it is possible to prevent the table from meandering when the table is driven.

Pressure fluid is supplied to the static pressure pocket 17 via a throttle resistance controlled by a variable throttle valve with a built-in diaphragm, and the table 15 is floated and supported to the point where there is no metal contact. Even when a workpiece is placed, the sliding resistance of the table is extremely small, and the load on the feed drive system can be reduced. Also, a change in the weight acting on the table causes a change in the gap on the guide surface, which changes the pocket pressure.The variable throttle valve is controlled by this change in pocket pressure, and the throttle resistance is adjusted to compensate for the change in the gap. It provides an extremely rigid guiding action that is unlike any other.

<Effects of the Invention> As described above, in the present invention, the table is supported by static pressure on the horizontal support surface that supports the weight, and the table is supported in the lateral direction by the lateral guide surface parallel to the direction of gravity. Since the material is guided by the material and an appropriate frictional force is applied, the dynamic rigidity in the feeding direction can be increased without increasing the load on the feeding drive system.

In addition, pressure fluid is supplied to the static pressure pocket via a diaphragm-type variable throttle valve to promote pressure compensation, resulting in extremely high static pressure support rigidity, which prevents vertical displacement of the table due to weight changes. rarely occurs.

Furthermore, since the horizontal support surface and the lateral guide surface are arranged symmetrically with respect to the feed screw, meandering of the table is effectively prevented.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a conventional device, Fig. 2 is a sectional view showing an embodiment of the present invention, Fig. 3 is a plan view showing a hydraulic circuit, and Fig. 4 is a longitudinal sectional view of a variable throttle valve. , FIG. 5 is a plan view showing surface pressure applying means on the lateral guide surface, FIGS. 6 and 7.
8 shows the position adjustment mechanism of the wedge-shaped member, FIG. 6 is a sectional view taken along the line Vl--Vl in FIG. 8, and FIG. 7 is a sectional view taken along the line ■-■ in FIG. 8. It is. 10...Bed, 11.12...Horizontal support surface, 13
．． 14... Lateral guide surface, 15... Table, 17
...Static pressure pocket, 18...Variable throttle valve, 21...
・Diaphragm, 22, 23... Valve housing, 24
... Seat part, 25... Spring, 26...
Nozzle, 40... Wedge-shaped member, 41... Parallel member, 4
3...Tension bolt, 44...Push port. Patent Applicant: Toyota Machine Machinery Co., Ltd. Figure 1 Figure 4

Claims (4)

[Claims] (1) On the bed that supports the feed screw for feeding the movable table, a pair of horizontal support surfaces that support the weight are placed on the outside on both sides of the feed screw, and the feed screw has a direction guiding function. A pair of lateral guide surfaces parallel to the direction of gravitational force are arranged symmetrically on the inside, and a static pressure pocket is formed on the lower surface of the table that is received by the horizontal support surface. A fluid supply means for supplying pressurized fluid through a throttle is connected to the 1, and a guide part protruding from the lower surface of the table that comes into sliding contact with the lateral guide surface 1, and between the guide member and the lateral guide surface. A guide device for a heavy movable platform, characterized in that it is provided with surface pressure applying means. (2) The guide device for a heavy movable platform according to claim 1, wherein the fluid supply means includes a variable throttle valve that increases or decreases the throttle resistance according to changes in the pressure inside the static pressure pocket. (3) The variable throttle valve includes a diaphragm that can be deformed in response to static pressure pocket pressure, and a diaphragm that is disposed close to the static pocket pressure introduction side of the diaphragm and communicated with a pressure fluid supply source to deform the diaphragm. 3. A guide device for a heavy movable platform according to claim 2, further comprising a nozzle whose aperture resistance changes depending on the size of the nozzle. (4) The surface pressure applying means includes a wedge-shaped member inserted between the guide member and the lateral guide surface, and an adjusting means for adjusting the relative movement of the wedge-shaped member. A guide device for a heavy movable platform as described in Scope 1.