JP2000227118A - Control system of driving device using gas bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely detect cutting-off or opening of compressed air when the compressed air was cut-off or opened anywhere in a supply path. SOLUTION: This control system drives a spindle device 11 where a static pressure gas bearing spindle 12 is installed with supplying compressed air thereto, and, for instance, is provided with a flowmeter 14 which detects a change in a flow rate caused by cutting-off or opening of the compressed air during operation of the spindle device 11 in a compressed air supply path 13 to transmit a forced outage signal from a control circuit 15 to the spindle device 11 based on a detected signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a control system for a driving device using a gas bearing, and more particularly, to a control system for driving a driving device incorporating a gas bearing while supplying a compressed gas to the gas bearing.

[0002]

2. Description of the Related Art For example, as a rotary drive device using a gas bearing, there is a spindle device such as a drilling machine, a precision machine, an electrostatic coating machine, and the like. In this spindle device, a compressed gas is supplied to a gas bearing to support the main shaft in a non-contact manner with a hydrostatic bearing. In addition, examples of a linear drive device using a gas bearing include a semiconductor and liquid crystal related manufacturing and inspection device. These devices support the movable table in a non-contact manner by static pressure bearings by supplying compressed gas to the gas bearings, as described above.

[0003] These rotary drive and linear drive are:
It is used for a processing device or a measuring device that requires high precision in order to be processed with high precision and obtain good durability. If compressed gas is not properly supplied to the gas bearings incorporated in these drive units, the movable parts will not float with respect to the fixed parts, not only will the original drive be impossible, but also damage if it occurs during drive. May be affected.

Therefore, as shown in FIG. 5, a pressure gauge 4 is provided in a supply path 3 for supplying a compressed gas to a gas bearing 2 incorporated in the driving device 1. When shut off or opened, the pressure change of the compressed gas generated at that time is detected by the pressure gauge 4, and a forced stop signal is sent from the control circuit 5 to the drive unit 1 based on the detected signal, and the operation is forcibly stopped. Is controlled.

[0005]

However, as described above, if the pressure gauge 4 is provided in the compressed gas supply path 3 and the pressure change of the compressed gas at the time of shutting off or opening is detected by the pressure gauge 4, There were the following problems.

[0008] That is, as shown in FIG. 5, when the compressed gas is shut off or released in the supply path 3 on the upstream side of the place where the pressure gauge 4 is provided (point a in the figure), the pressure change is remarkable. Therefore, there is no problem because the pressure change can be reliably detected by the pressure gauge 4.

However, when the compressed gas is shut off or opened downstream of the pressure gauge 4 in the supply path 3 (point b in the figure), the pressure change is very small. , It may be impossible to forcibly stop the driving device 1.

Therefore, the present invention has been proposed in view of the above-mentioned problems, and an object of the present invention is to provide a method for compressing or compressing compressed gas no matter where it occurs in the supply path. An object of the present invention is to provide a control system capable of reliably detecting shutoff or release of gas.

[0009]

According to the present invention, there is provided a control system for driving a driving device incorporating a gas bearing while supplying a compressed gas to the gas bearing. A flow rate detecting means for detecting a flow rate change generated by shutting off or opening the compressed gas is provided in the compressed gas supply path, and the driving device can be forcibly stopped based on the detection signal.

In the present invention, as described above, in order to monitor the change in the flow rate of the compressed gas, the supply path of the compressed gas is
Regardless of the location before or after the location where the flow rate detecting means is provided, the flow rate change due to blocking or opening of the compressed gas is remarkable, so that the flow rate change can be reliably detected.

When the gas bearing incorporated in the driving device is used at a high speed rotation or in an environment where the temperature changes drastically, the flow rate changes greatly during use.
It is desirable to use pressure detecting means for detecting a pressure change generated by shutting off or opening the compressed gas together with the flow rate detecting means.

In this case, the pressure detecting means is provided separately from the flow rate detecting means in the compressed gas supply path, or the pressure detecting means and the flow rate detecting means are unitized to detect the flow rate change and the pressure change simultaneously. It is possible to dispose the composite detecting means in the supply path of the compressed gas.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail. In the following embodiment, a rotary drive device using a gas bearing is applied to a spindle device such as a hole drilling machine, a precision processing machine, and an electrostatic coating machine. In this spindle device, a compressed gas is supplied to a gas bearing to support the main shaft in a non-contact manner with a hydrostatic bearing.

The present invention relates to a linear drive device using a gas bearing, such as a semiconductor and liquid crystal-related manufacturing / inspection device, which supplies a compressed gas to the gas bearing to make the movable table non-contact and a static pressure bearing. It is also applicable to supporting ones.

In the embodiment shown in FIG. 1, a flow meter 14 is provided in a supply path 13 for supplying compressed air to a hydrostatic air bearing spindle 12 (described later) which is a gas bearing incorporated in a spindle device 11 which is a driving device. And the flow meter 1
A control signal is sent from the control circuit 15 to the spindle device 11 based on the detection signal output from the control unit 4.

The hydrostatic air bearing spindle 12 incorporated in the spindle device 11 has a rotating shaft 16 as shown in FIG.
A main shaft member 18 including a thrust plate 17, a cylindrical housing 20 in which an air supply passage 19 is formed, and a bearing sleeve 21 fixed to the housing 20. An air supply hose 22 communicating with the air supply passage 19 is attached to the housing 20, and the air supply hose 22 is connected to the compressed air supply path 13 (see FIG. 1).

In this hydrostatic air bearing spindle 12, compressed air supplied from an air supply hose 22 is supplied to the housing 20.
Air supply throttle 2 of bearing sleeve 21 through air supply passage 19 of
The main shaft member 18 is rotatably supported in a radial direction and a thrust direction in a non-contact manner by being discharged from the bearings 3 and 24 into the bearing gap.

In the spindle device 11 in which the hydrostatic air bearing spindle 12 is incorporated, for example, when the compressed air is shut off or released during its operation, the flow meter 14 detects a change in the flow rate of the compressed gas generated at that time. In the compressed gas supply path 13, regardless of whether the compressed air is cut off or opened before or after the flow meter 14 (points A and B in the figure), the flow rate change due to the cut off or opening of the compressed gas is remarkable. The change in the flow rate can be reliably detected. This flow meter 1
A forced stop signal is sent from the control circuit 15 to the spindle device 11 based on the detection signal output from the control unit 4, and the operation is forcibly stopped.

When the hydrostatic air bearing spindle 12 incorporated in the spindle device 11 is used at high speed rotation or in an environment where the temperature changes drastically, the flow rate changes frequently during use. It is desirable to use pressure detecting means for detecting a pressure change generated by shutting off or opening the gas, for example, a pressure gauge together with the flow meter. In that case,
As shown in FIG. 3, the pressure gauge 25 is connected to the compressed gas supply path 13.
In addition, a pressure gauge 25 and a flow meter 13 are united as shown in FIG. 4 separately from the flow meter 14, or a composite detector 26 for simultaneously detecting a flow rate change and a pressure change is supplied with compressed gas. It is possible to dispose it on the route 13.

[0020]

According to the present invention, in a control system for driving a driving device incorporating a gas bearing while supplying a compressed gas to the gas bearing, a flow rate change generated by shutting off or opening the compressed gas is detected. Since the flow rate detecting means is disposed in the supply path of the compressed gas and the driving device can be forcibly stopped based on the detection signal, the drive of the compressed gas can be stopped or opened anywhere in the supply path. Since the device can be forcibly stopped, the safety and reliability are greatly improved without damaging the drive device.

Further, even when the gas bearing incorporated in the driving device is used at a high speed rotation or in an environment in which the temperature changes drastically, a pressure detection for detecting a pressure change generated by shutting off or opening the compressed gas. By using the means together with the flow rate detecting means, the forced stop of the drive device can be reliably performed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a specific example of a gas bearing incorporated in a driving device.

FIG. 3 is a schematic configuration diagram showing another embodiment of the present invention.

FIG. 4 is a schematic configuration diagram showing another embodiment of the present invention.

FIG. 5 is a schematic configuration diagram showing a conventional example of a control system of a driving device using a gas bearing.

[Explanation of symbols]

 Reference Signs List 11 drive device (spindle device) 12 gas bearing (static pressure air bearing spindle) 13 supply path 14 flow rate detection means (flow meter) 15 control circuit

Claims (3)

[Claims] In a control system for driving a driving device incorporating a gas bearing while supplying a compressed gas to the gas bearing, a flow rate detecting means for detecting a flow rate change generated by shutting off or opening the compressed gas is compressed. A control system for a drive device using a gas bearing, wherein the control device is provided in a gas supply path, and the drive device can be forcibly stopped based on a detection signal thereof. 2. The gas bearing according to claim 1, wherein a pressure detecting means for detecting a pressure change generated by shutting off or opening the compressed gas is provided in the compressed gas supply path together with the flow rate detecting means. The control system of the drive unit used. 3. A control system for driving a driving device incorporating a gas bearing while supplying a compressed gas to the gas bearing, wherein a combined change in the flow rate and the pressure generated by shutting off or opening the compressed gas is simultaneously detected. A control system for a drive device using a gas bearing, wherein a detection means is provided in a supply path of a compressed gas, and the drive device can be forcibly stopped based on a detection signal thereof.