JPH0641790Y2 - Vertical table feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a vertical table feeding device incorporated in a positioning mechanism or the like of a precision machining device or a precision measuring instrument that requires high accuracy.

[Conventional technology]

For example, a disk master processing machine for video disks and audio disks requires rotation and rectilinear accuracy of 0.1 μm or more, which is one digit higher than the processing accuracy of the master, in order to guide and position the spindle that holds the master and the table on which the processing head rides. To do. As a bearing that can realize this accuracy, there is a static pressure gas bearing that supports a load with high-pressure gas supplied from the outside. Gas bearings do not have solid contact as in the case of commonly used rolling bearings, so accuracy does not deteriorate due to aging, and since grease or liquid lubricating oil is not used as a lubricant, the atmosphere is maintained. There is no risk of contamination, and there is an advantage that it can be suitably used even in a clean room.

Conventionally, as a high precision table device using such a static pressure air bearing, there is one disclosed in, for example, Japanese Patent Laid-Open No. 59-110527. This is a moving table device that moves a sample linearly and is equipped with linear pressure static pressure air bearing units at three locations around the sample and the moving directions of the respective units are aligned. Further, a linear moving body for placing a sample is provided by further including a connecting body that integrally connects these linear moving bodies.

Since the moving table is supported and guided at three points via the hydrostatic air bearing, the guide length is expanded as compared with the case where it is supported at two points. Further, since there are few restraint conditions as compared with the case of supporting at four points, there are advantages such as easy assembling, easy accuracy and economical.

[Problems to be solved by the invention]

However, in such a conventional table device, the guide shafts of the three static pressure air bearing units that support the upright table at the upper one point and the lower two points are both on the vertical surface of the base and this. It is horizontally arranged between the vertical tables facing each other upright, that is, on the back surface side of the table. for that reason,
The self-weight of the table causes a torsional moment to act on the guide shaft, resulting in the following problems.

The vertical table tilts forward, making it difficult to ensure assembly accuracy.

When the guide shaft is apt to be torsionally deformed and the supply of the pressurized air to the static pressure air bearing is interrupted, the bearing surfaces of the guide shaft and the static pressure air bearing are unbalanced and damaged.

After all, when such shaft deformation and bearing surface damage occur, it is difficult to maintain the high accuracy that is a characteristic of the hydrostatic air bearing.

Furthermore, it is not easy to accurately assemble the static pressure air bearing on the back surface side of the upright table, and it is difficult to obtain the mounting accuracy.

Therefore, the present invention solves the above-mentioned problems by providing a vertical table feeding device that does not tilt the table forward, does not exert a torsional moment on the guide shaft, and is extremely easy to assemble a hydrostatic air bearing. The purpose is to do.

[Means for solving problems]

This invention that achieves its purpose is an upright table,
An upper guide bearing device and a lower guide bearing device for supporting the same are provided, the lower guide bearing device is disposed substantially directly below the center of gravity of the table and disposed on a mounting base, and the upper guide bearing device is mounted on the mounting base. The table feed drive system is fixed to the column in the vicinity of the plane including the guide bearing devices.

[Action]

Since the lower guide bearing device, which is located just below the center of gravity of the table, supports the load of the table, no torsion moment acts on the guide shaft. An upper guide bearing device at the top of the column upright on the mount supports the top of the table and prevents the table from tipping.

As a result, it becomes easy to assemble and adjust the vertical table and the guide bearing device, and it is easy to ensure the assembly accuracy. Further, even if the guide shaft is not twisted and deformed and the supply of the pressurized air to the hydrostatic air bearing is cut off, the bearing surface will not be damaged due to uneven contact.

Thus, the vertical table feeding device can always be maintained with high accuracy.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

1 and 2 show one embodiment of the present invention. The upright table 1 has an inverted Y-shape with a narrow upper portion and a wide lower portion. The table 1 is supported by two upper and lower guide bearing devices, an upper guide bearing device 10 and a lower guide bearing device 20, and is disposed on a mounting base 30. The lower guide bearing device 20 is disposed almost directly below the center of gravity of the table 1 and is disposed on the upper surface 31 of the mounting base 30, and the upper guide bearing device 10 is disposed above the column 32 which is upright on the mounting base 30. A table feed drive system 40 is fixedly mounted on the column 32 in the vicinity of the plane S including both guide bearing devices 10 and 20.

That is, the upper guide bearing device 10 includes a hollow quadrangular prism-shaped upper guide shaft 11 and an upper guide shaft 11 that is movably inserted in the axial direction.
It has a single support bearing 12, and both ends of the shaft are supported by guide shaft support 13 and fixed to the upper surface 33 of the column 32.
The support bearing 12 is attached by a bolt 15 to the back side of the center of the table 1 via a mounting plate 14.

On the other hand, the lower guide bearing device 20 has a lower guide shaft 21 which is also in the shape of a hollow quadrangular prism, and two support bearings 22, 22 which are axially movably inserted into the lower guide shaft 21 and are separated from each other. Both ends of the shaft are supported by the guide shaft support 23 and fixed to the upper surface 31 of the mounting base 30. The two spaced support bearings 22 and 22 are fixed to the lower surface side of the lower end 2 of the table 1 which is projected a little forward, so as to receive the weight of the table 1.

As described above, the lower guide bearing device 20 mainly supports the weight of the table 1 and is also a guide reference for moving the table 1. In order to improve straightness and load bearing capacity, the two support bearings 22 are separated from each other in the axial direction. The structure is made to be. On the other hand, the upper guide bearing device 10 does not need the function of supporting the weight of the table 1 unlike the conventional one, and its main function is simply to prevent the table 1 from falling. Support bearings 12 are sufficient.

In this way, in order to form a three-point support structure that provides the minimum required restraint and stabilize the structure of the entire device,
The length L1 of the upper guide shaft 11 at the higher position is formed shorter than the length L2 of the lower guide shaft 21 parallel thereto.

The upper and lower support bearings 12, 12 are both static pressure gas bearings of the same type, and have the structure shown in FIG. 3, for example. That is, the support bearing main body 25 having a rectangular parallelepiped outer shape has a through hole 26 through which the guide shaft 11 or 21 is inserted and is formed so as to completely enclose the outer circumference of the guide shafts 11 and 21. A minute bearing clearance C is provided between the outer peripheral surface of the shaft 11 or 21 and the inner peripheral surface (bearing surface) of the through hole 26, and the bearing clearance C is provided, for example, via the self-made throttle 27 to supply air. The pressurized gas from 28 is delivered.

The table feed drive system 40 for moving the table 1 while guiding it with the upper and lower guide shafts 11 and 21 is a feed and motor 41 fixed to a motor support bracket 41A attached to a column 32.
And a feed screw 42 directly connected to this, and a nut 43 screwed to the screw 42 and fixed to the lower surface side of the table 1 through the mounting flanges 44, 45.
It is installed on the front side of.

If the span between the support bases 23 that support both ends of the lower guide shaft 21 is long, the lower guide shaft 21 may bend and bend downward due to the weight of the table 1 or the like. In order to prevent this bending, in this embodiment, an intermediate support base 50 that supports the lower surface of the central portion of the lower guide shaft 21 is provided on the mounting base upper surface 31.

The intermediate support base 50 serves as a mechanism for finely adjusting the straightness of the lower guide shaft 21 in a direction traversing the lower guide shaft 21 (indicated by arrow mark a in FIG. 5) and in a vertical direction (arrow mark ro in FIG. 4). It is equipped with a fine adjustment mechanism to
It is shown in FIG. That is, the base plate of the intermediate support base 50.
The longitudinal direction of 51 is fixed to the upper surface 31 of the mounting base 31 with bolts with its longitudinal direction oriented orthogonal to the lower guide shaft 21. At one end of the base plate 51, a rising portion 53 into which a lateral deviation adjusting screw 52 is screwed is provided, and a guide groove 54 is formed on the upper surface in the longitudinal direction. On the base plate 51, the U-shaped lateral movement base 55 having the rising portions 55a and 55b formed at both ends and the convex portion 56 formed on the bottom surface is placed.
56 is slidably fitted in the guide groove 54. A U-shaped guide shaft holding base 57 is further fitted on the horizontal moving base 55 so as to be slidable in the vertical direction. This guide shaft holder 57
The bottom surface 57a of the is formed on the slope having a gentle slope in the longitudinal direction, and between the bottom surface 57a and the lateral movement base 55 described above, the height adjusting plate 58 having the slope 58a having the same slope as the above is provided. It is slidably inserted in the longitudinal direction. Then, one end face in the longitudinal direction of the height adjusting plate 58 is engaged with the tip of a height adjusting screw 59 screwed to one of the lateral moving bases 55 and the rising portion 55b. Further, fixing screws 60 and 61 for tightening and fixing the guide shaft holding base 57 from both sides are screwed to the rising portions 55a and 55b of the lateral movement base 55.

The lower guide shaft 21 is adapted to be fitted into the concave portion of the U-shaped guide shaft holding base 57 of the intermediate support base 50 and fixed with bolts.

Next, the operation will be described.

The load due to the own weight of the table 1 is supported by the lower guide shaft 21 which is located substantially below the center of gravity of the table and mounted on the upper surface 31 of the mounting base. Therefore, when the device is stopped by shutting off the bearing air pressure, the torsion moment does not act on both the upper guide shaft 11 and the lower guide shaft 21, and there is no damage due to uneven contact of the bearing surface as in the conventional case. .

Since the upper guide shaft 11 is attached to the horizontal upper end surface 33 of the column 32 which is erected on the mounting base 30, the upper guide shaft 11 is much easier to attach than the conventional one, and the attaching accuracy is also improved. This upper guide shaft 11
Supports the upper part of the table 1 via the upper support bearings 12 and prevents only the table 1 from falling.

In this way, the roles of the upper and lower guide shafts 11 and 12 are substantially independent, so that it is possible to set the size and rigidity of the respective guide shafts and bearings according to their roles. For example, the lower guide shaft 21 and the support bearing 22 that support the weight of the table 1 are large,
In addition, the upper guide shaft 11 and the support bearing 12, which do not have to support the own weight of the table 1, are set to have a high rigidity against the downward load, and the rigidity in the lateral direction is large enough to prevent the table 1 from falling. May be set.

Further, in this way, the role each guide bearing device 10, 20 should play is clear, and since there is no multiple constraint, precision adjustment only needs to be performed for each bearing, which facilitates precision adjustment and makes the entire device highly accurate. It is easily possible to maintain.

Further, by disposing the shaft of the feed screw 42 of the table feed drive system 40 in the vicinity of the plane S including the centers of the upper and lower guide bearing devices 10 and 20, twisting due to the axial driving force is eliminated,
As a result, highly accurate feed can be realized.

Strictly speaking, the lower guide shaft 21 receives not only the weight of the table 1 but also the weight of the support bearing 12 of the upper guide bearing device 10 and the weight of a movable body such as a jig attached to the table 1, Since the movable body and the upper support bearing 12 are distributed to both the front surface side and the back surface side of the table 1, they are easily balanced and a large torsional moment does not occur.

In addition, the support bearings 12 and 22 consisting of static air bearings are
Since the outer circumference of 1,21 is completely wrapped, the pressure of the gas that is the lubricant is balanced and no unbalanced load occurs.

In addition, the arrangement of the lower guide bearing device 22 is strictly the table 1
It is not limited to just below. For example, table 1
The weight of the jig, etc. mounted on the surface of the
When the torsional moment is generated due to the total weight of the table 1 and the jig etc., the lower guide bearing device 22 is placed below the center of gravity of the total weight.
Is preferably provided. That is, in such a case, the arrangement of the lower guide bearing device 22 is shifted to the front slightly below the center of gravity of the table 1.

Although the static pressure gas bearing of the above-mentioned embodiment is provided with the self-made throttle, it may be provided with an orifice throttle, a surface throttle, a porous throttle, or the like.

Further, the upper and lower guide shafts 11 and 21 are not limited to the quadrangular prism, and may be other polygonal columns or columns. In that case, it goes without saying that the shape of the bearing surface of the hydrostatic gas bearing is also changed according to the shape of the guide shaft.

Incidentally, as shown in FIGS. 6 and 7, it is also possible to stack a feed table device 70 for vertical movement in which feed directions are orthogonal to each other on the table 1 for horizontal movement in the above embodiment. Is. In the drawings of this other embodiment, 71 is a pair of vertical guide shafts provided in parallel, and both ends thereof are supported on the table 1 for horizontal movement. One support bearing 72 is inserted through each vertical guide shaft 71, and these support bearings 72 are inserted.
The vertical moving table 73 is attached to the 72, and the feed nut 74 is fixed to the lower surface of the vertical moving table 73, and the feed screw 75 screwed to this and the feed motor 76 (with encoder) directly connected to this Are also mounted on the table 1 for horizontal movement. 75A is a motor support bracket.

By doing so, the movable body can be mounted on the vertical movement table 73 and biaxially moved.

[Advantages of the Invention] As described above, according to the present invention, the table has an upright table and two upper and lower guide bearing devices that support the upright table, and the lower guide bearing device is located almost directly below the center of gravity of the table. And the upper guide bearing device is installed on the upper part of the column standing upright on the mount, and the table feed drive system is fixed and arranged on the plane including both guide bearing devices. Since it is installed, there is no tilting of the table and no twisting moment on the guide shaft, and the static pressure air bearing is extremely easy to assemble. As a result, a highly accurate vertical table feeder is provided. The effect of being able to be obtained is obtained.

[Brief description of drawings]

1 to 5 show an embodiment of the present invention.
The figure is a side view, FIG. 2 is a front view, FIG. 3 is a cross-sectional view of a support bearing which is a component, FIG. 4 is an enlarged front view of an intermediate support base, and FIG. 6 is a side view of another embodiment in which vertical moving table devices are stacked, and FIG. 7 is a front view thereof. 1 is a support base, 2 is a guide shaft, 3 is a base, 4 is a static pressure air bearing, and 5 is a table.

Claims (4)

[Scope of utility model registration request] 1. An upright table, and an upper guide bearing device and a lower guide bearing device for supporting the upright table, the lower guide bearing device being disposed on a mounting base substantially directly below the center of gravity of the table. The upper guide bearing device is arranged in the upper part of a column standing upright on a mounting table, and a table feed drive system is fixed to the column in the vicinity of a plane including the both guide bearing devices. Table feeder. 2. A lower guide bearing, wherein two support bearings are arranged apart from each other on a guide shaft of the lower guide bearing device, and one support bearing is arranged on a guide shaft of the upper guide bearing device. The vertical table feed device according to claim 1, wherein the guide shaft of the upper guide bearing device is shorter than that of the device. 3. The vertical table feed device according to claim 1 or 2, wherein the upper guide bearing device is fixed to an upper part of a column. 4. The vertical table feed device according to claim 1, wherein the guide bearing device is a hydrostatic bearing.