JP2000202729A - Linear drive for vacuum - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear drive for vacuum which is intended to have its vacuum chamber miniaturized and does not affect the vacuum in the vacuum chamber even if using a gas bearing. SOLUTION: A vacuum chamber 2 is provided in a device main unit 1, and also a linear drive 3 and a direct acting bearing 11 are set up in the outside of this vacuum chamber 2, an air spindle 19 is mounted in the linear drive 3 through the direct acting bearing 11, a turn table 26 is mounted in a table supporter body 25 inserted through a base 23 of the vacuum chamber 2, an endless state multiplex groove 28 is formed in the base 23, gas in the multiplex groove 28 is suction exhausted to outside the vacuum chamber 2, and a seal is formed between the turn table 26 and the base 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear driving device for vacuum used for performing various kinds of high-precision processing and inspection on a table in a vacuum chamber.

[0002]

2. Description of the Related Art In order to perform various kinds of high-precision machining and inspection on a turntable in a vacuum chamber, a rotary drive device is provided in a vacuum chamber, and a device having a turntable mounted on a spindle of the rotary drive device is known. Are known.
In this case, a gas bearing is used for maintaining high accuracy and durability of the rotary drive device, but a special seal may be provided so that the degree of vacuum in the vacuum chamber is not reduced by gas discharged from the gas bearing. It is known (see Japanese Patent No. 2602648).

On the other hand, in order to perform various kinds of high-precision processing and inspection, a device in which a table is mounted on a reciprocating linear drive device is installed in a vacuum chamber. In this case, a linear motion bearing of the table is used. In general, rolling bearings are used.

[0004]

As described in the above-mentioned patent publication, the conventional apparatus has a problem that the vacuum chamber becomes large because the entire apparatus is housed in the vacuum chamber.

When processing and inspection are performed in a vacuum chamber on a table driven by a linear drive device, it is desirable to use a gas bearing as a linear bearing from the viewpoint of maintaining high accuracy and durability. In the past, there was no effective sealing means to prevent the degree of vacuum in the vacuum chamber from being reduced by the gas flowing out of the gas bearing,
Rolling bearings with inferior precision were used.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a linear driving device for vacuum in which the size of the vacuum chamber can be reduced and the degree of vacuum in the vacuum chamber is not affected even if a gas bearing is used. And

[0007]

In order to solve the above-mentioned problems, the present invention provides a vacuum chamber in an apparatus main body, and a linear drive device and a linear motion bearing installed outside the vacuum chamber. A table support is attached to the drive device via the linear motion bearing, a part of the table support is passed through an opening provided in the base of the vacuum chamber, and the table is mounted on the table support in the vacuum chamber. At the same time, the table is brought closer to the base, and an endless multiple groove is formed around the opening of the base to cover the moving range of the table, and gas in each groove of the multiple groove is supplied to the outside of the vacuum chamber. And a seal was formed between the table and the base.

The above-mentioned linear motion bearing is a gas bearing,
A configuration in which the table support is an air spindle, wherein each of the multiple grooves has a parallel linear portion extending over a range in which the table is linearly driven, and includes two linear portions belonging to the same groove. A configuration in which both ends are continuous with each other at a semicircular portion can be adopted.

[0009] Further, it is possible to adopt a configuration in which the degree of vacuum of each of the above-mentioned multiple grooves is gradually increased from the one close to the atmosphere to approach the degree of vacuum in the vacuum chamber.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIGS. 1 and 2, a vacuum chamber 2 is provided on an upper portion of an apparatus main body 1, and a linear driving device 3 is provided on a lower surface of the apparatus main body 1.

The apparatus main body 1 is provided with a guide groove 4 (see FIG. 2) along the moving direction of the linear drive device 3, and a small opening 5 is provided on the bottom surface of the guide groove 4 near the linear drive device 3. Is provided, and a large opening 6 is provided at a far side. The large opening 6 reaches the end of the guide groove 4 and is open to the outside.

A stage 9 is slidably fitted in the guide groove 4, and a fixing member 12 of a linear motion bearing 11 is fixed to both sides of the guide groove 4. The movable member 13 of the linear motion bearing 11 is attached to the stage 9, and guides the stage 9 in the length direction of the guide groove 4.

The linear drive 3 has a ball screw 15 driven by a motor 14 and a nut 16 screwed to the ball screw 15. Holder 17 of the nut 16
Is fixed to the lower surface of the stage 9 through the small opening 5.

The stage 9 is provided with a mounting hole 18 at the center thereof. The body of an air spindle 19 is inserted into the mounting hole 18, and the flange 21 of the air spindle 19 is connected to the mounting hole 18. It engages around the upper end and is fixed to the stage 9 by bolts 22.

The base 23 of the vacuum chamber 2 is provided above the stage 9 so as to oppose it, and an oval opening 24 is provided at the center thereof. As shown in FIG. 3, the opening 24 has a shape in which two parallel sides on the same side are continuous with each other in a semicircular arc, and the spindle portion of the air spindle 19 is a table support 25. A table support 25 is inserted through the opening 24 with a required gap. The length of the opening 24 is set to a length equal to the stroke of the linear drive device 3, and the table support 25
Moves between both ends of the opening 24 (see the dashed line in FIG. 3).

A disk-shaped turntable 26 is mounted on the upper end of the table support 25 in the vacuum chamber 2. The lower surface of the turntable 26 is the vacuum chamber 2
And a small gap, and a seal is formed by the conductance of the gap. On the upper surface of the base 23 facing the turntable 26,
Around the opening 24, a multiple groove 28 including three endless grooves 27 similar to the opening 24 is formed. The multiple groove 28 is formed to have a size that can cover the moving range of the turntable 26 described above.

Each of the grooves 27 has an independent suction port 29, which is connected to a vacuum pump (not shown). The groove 27 closest to the opening 24 has the lowest degree of vacuum. The gas is suctioned and evacuated so that the outermost groove 27 has a height equal to or close to the degree of vacuum in the vacuum chamber 2.

The linear driving device for vacuum according to the embodiment is as described above. A work is set on a turntable 26, and the linear driving device 3 is driven while the air spindle 19 is driven to rotate. Move linearly. Turntable 26 and base 2 of vacuum chamber 2
3 is formed by suctioning and exhausting the gas in the multi-groove 28 by a vacuum pump.
External gas flowing from the vacuum chamber 4 into the vacuum chamber 2 is blocked by the seal, whereby the vacuum of the vacuum chamber 2 is maintained.

Further, since the turntable 26 moves without contacting the base 23 of the vacuum chamber 2, the rotation accuracy of the air spindle 19 is not affected.

When the linear motion bearing 11 is formed of a gas bearing, the accuracy of the linear movement of the air spindle 19 is further improved.

In the illustrated case, the linear drive device 3 comprises a motor 14 and a ball screw 15,
The linear drive device 3 may be constituted by a linear motor.

Further, in place of the air spindle 19, an appropriate rotary drive device or a simple table support may be used.

[0024]

As described above, according to the present invention, the linear drive device and the linear motion bearing are provided outside the vacuum chamber, and do not affect the vacuum maintenance of the vacuum chamber. There is an advantage that there is no restriction on the selection of the vacuum chamber, and there is also an effect that the vacuum chamber can be miniaturized.

Further, the vacuum in the vacuum chamber is maintained by the synergistic effect of the seal by the conductance of the gap between the table and the base of the vacuum chamber and the seal by the vacuum suction, and the table is moved without contact. Therefore, if the size of the table is increased, the rotational accuracy of the spindle can be improved by its inertia effect.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view taken along line III-III in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Device main body 2 Vacuum chamber 3 Linear drive device 4 Guide groove 5 Small opening 6 Large opening 9 Stage 11 Linear bearing 12 Fixed member 13 Movable member 14 Motor 15 Ball screw 16 Nut 17 Holder 18 Mounting hole 19 Air spindle 21 Collar 22 Bolt 23 Base 24 Opening 25 Table support 26 Turntable 27 Groove 28 Multi-groove 29 Suction port

Continued on the front page F term (reference) 3C016 AA00 3C045 FD10 3J102 AA02 BA05 CA19 EA02 EA22 GA19

Claims (5)

[Claims] 1. A vacuum chamber is provided in an apparatus main body, a linear drive device and a linear motion bearing are installed outside the vacuum chamber, and a table support is attached to the linear drive device via the linear motion bearing. A part of the table support is passed through an opening provided in the base of the vacuum chamber, a table is mounted on the table support in the vacuum chamber, and the table is brought close to the base. An endless multiple groove is formed around the table so as to cover the moving range of the table, and the gas in each groove of the multiple groove is sucked and exhausted to the outside of the vacuum chamber to form a seal between the table and the base. Linear drive for vacuum. 2. The linear driving device for vacuum according to claim 1, wherein said linear motion bearing is a gas bearing. 3. The linear driving device for vacuum according to claim 1, wherein the table support is an air spindle. 4. Each of the grooves of the multiple grooves has a parallel linear portion extending over a range in which the table is linearly driven, and two ends of the two linear portions belonging to the same groove are mutually semicircular. 4. The vacuum linear drive device according to claim 1, wherein the linear drive device is continuous. 5. The vacuum chamber according to claim 1, wherein the degree of vacuum of each of the multiple grooves is increased stepwise in order from the closest to the atmosphere to approach the degree of vacuum in the vacuum chamber. 5. The linear driving device for vacuum described in 1.