JPH01205584A - Laser emission device - Google Patents

Abstract

PURPOSE:To make the whole device small-sized while preventing contamination of optical parts by lubricating oil by using a turboblower as a blower, while constituting the bearing of a one axis control magnetic bearing as to the thrust direction. CONSTITUTION:A turboblower 15 having two turboblades arranged so that thrust force may be applied in the reverse direction as a blower, which circulates laser gas inside a discharge tube 1. Further, a one axis control magnetic bearing as to the thrust direction is used as the bearing thereof. In this way, a shape and the weight can be reduced, while preventing a pulsating flow of the blower, since the blower is the turboblower. Further, since the magnetic bearing is used for the bearing, there is little vibration, while preventing contamination of optical parts by an oil component of lubricating oil, consequently for preventing deterioration of laser output and a beam characteristic. Also, since two turboblades are arranged so that thrust force may be applied in the reverse direction, the force in the thrust direction is balanced so as to increase stability.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to high-power lasers such as CO2 lasers for processing, and in particular, to CO2 laser oscillations that are smaller and lighter and have improved oscillation characteristics, reliability, and maintainability. Regarding equipment.

[Conventional technology]

FIG. 5 shows a configuration diagram of a conventional CO2 laser oscillation device. In the figure, there are output coupling mirrors 2 at both ends of the discharge tube 10.
A total reflection mirror 3 is installed.

Further, two metal electrodes 4 and 5 are attached to the outside of the discharge tube 1, and a high frequency voltage is applied between them by a high frequency type #6, and a high frequency glow discharge is generated inside the discharge tube 1, causing laser excitation. It will be done.

The optical axis of the laser beam inside the discharge tube 1 is indicated by 13, and the optical axis of the laser beam taken out from the output coupling mirror 2 is indicated by 14.

When the laser oscillation device is started, the entire interior of the device is first evacuated by the vacuum pump 12. Then, the valve 11 is opened and a predetermined flow rate of laser gas is guided from the main unit 10, and the gas pressure inside the device reaches the specified value.After that, the vacuum pump 12 is evacuated and the supplementary gas is introduced, and the gas pressure is maintained at the specified value. A portion of the laser gas continues to be replaced with fresh gas, thereby preventing gas contamination.

Further, in FIG. 5, a roots blower 9 circulates the laser gas within the apparatus. Its purpose is to cool the laser gas. For CO2 lasers, approximately 20% of the injected electrical energy
Some are converted into laser light and others are consumed for gas heating. However, according to theory, the laser oscillation gain is equal to the absolute temperature T = (
Since it is proportional to the power of 3/2), forced cooling of the lede gas is necessary to increase the oscillation efficiency. Laser gas is approximately 1
It passes through the discharge tube at a flow rate of 00 m/sec, flows in the direction shown by the arrow, and is guided to the cooler 8. Here, heating energy mainly due to discharge is removed.

Since compression heat is generated in the Roots blower 9, the gas passes through a cooler 7 before being led back to the discharge tube.

Since these coolers 7 and 8 are well known, detailed explanation will be omitted.

[Problem to be solved by the invention]

The conventional laser oscillation device shown in Part 5 has the following problems.

First, since the Roots blower is a positive displacement fan that rotates at a low speed, it is large in size and weight, and the laser oscillator itself is large.

Second, there is a pulsating flow in the air blowing, and the laser output is affected by this.

Third, a considerable amount of vibration is generated from the roots blower 9,
No adverse effect on laser beam bowing stability.

Fourth, since a rolling bearing is used in the Roots blower 9, lubricating oil components mix into the laser gas and contaminate optical components, resulting in a decrease in output and mode deformation. For this reason, in high-output CO2 lasers, the laser gas is constantly replaced, which accounts for a considerable portion of operating costs. Even if this is done, it is necessary to periodically replace or clean the optical components, which requires a great deal of effort for maintenance. Additionally, the need for lubrication also poses a maintenance problem.

[Means to solve the problem]

In order to solve the above problems, the present invention provides a gas laser oscillation device having a discharge tube that excites the laser by gas discharge, an optical resonator that performs laser oscillation, etc., in which the blower is constituted by a turbo blower, and the bearing of the blower is A laser oscillation device is provided that is characterized by being a uniaxially controlled magnetic bearing with respect to the thrust I direction.

Furthermore, a laser oscillation device is provided in which two turbo blades are arranged so that their thrust directions are opposite to each other.

[Effect]

Since the blower is a turbo blower, the shape and weight are reduced and there is no pulsation in the blower.

Furthermore, since a magnetic bearing is used for the bearing, there is little vibration, there is no contamination of the optical components by lubricating oil, and there is no need for oil lubrication.

Furthermore, since the turbo blades are arranged so that the thrust direction is angled in the opposite direction, the force in the thrust direction is balanced.
Increased stability.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

1M shows an overall configuration diagram of an embodiment of the laser oscillation device of the present invention. Components that are the same as those in FIG. 5 are given the same reference numerals, and detailed explanation thereof will be omitted. The structure of the discharge tube 1, the high frequency power source 6 for gas excitation, the supply of fresh gas from the gas phone 10, etc. are the same as in the case of FIG. 5, and their explanation will be omitted, and only the characteristic parts will be explained.

A feature of the present invention is that a turbo blower 15 is used instead of the Roots blower 9 in the fifth version. Since the efficiency of the turbo blower 15 is much higher than that of the Roots blower 9, the heat of compression can be ignored, and the cooler 7 in the latter stage of FIG. 5 can be omitted.

Although the cooler 7 is not shown in FIG. 1, it may be provided depending on the situation.

Figure 2 shows a structural diagram of a turquoise blower. Here, the turbo blade 16 is shown as a centrifugal blade, but even if it is a diagonal flow blade,
It may also be an axial flow blade. The turbo blade 16 is rotated at a high speed of about 100,000 PPM by a morph consisting of a rotor 17 and a stake 18 attached to a shaft.

Therefore, compared to a low-speed Roots blower, the volume is smaller in inverse proportion to the rotation speed.

Furthermore, a single-axis controlled magnetic bearing with a thrust bearing is used to support the shaft. This single-axis control magnetic bearing was adopted for the following technical reasons.

First, in radial-haired magnetic bearings, it is usually difficult to exceed 60,000 RPM due to centrifugal failure of the magnetic iron plate of the rotor. This is due to the complicated shaft structure.
There is also the issue of not being able to exceed the next critical speed. On the other hand, in the case of single-axis thrust bearing control, all of these causes can be eliminated.

The second requirement is cost.Since the price of sensors and the like is a major factor in the price structure, reducing the number of control axes is meaningful in terms of cost. In FIG. 2, the rotor 17 is held vertically.

Since the turbo blades 16 rotate in laser gas at a low pressure of about 55 Torr, substantially no load is applied to them in the radial direction. Therefore, the shaft is held in the radial direction by the rigidity of the two upper and lower thrust rings.

In FIG. 2, the upper metal disk 21 has two coils 19.
The position is constrained by 20. Lower metal disc 24
are similarly constrained in position by coils 22,23.

The shaft sensor 25 detects the position of the shaft in the thrust direction and controls the coil current.

Here, we have shown an example in which thrust bearing magnetic bearings are installed in two positions above and below the shaft, but it is also possible to use electromagnets to control either the top or bottom and hold the rest in the radial direction using the repulsive force of the permanent magnet. good. In that case, on the permanent magnet side, it is necessary to apply a tensile force in the axial direction that opposes the control force using the permanent magnet as well.

In the above description, since the magnetic bearing itself is known, the control device and auxiliary hair ring for the magnetic bearing are omitted. Further, the magnetic bearing, rotor 17, stator 18, etc. are installed in a sealed container sealed with a partition wall 31. Note that the partition wall 31 and the shirt 1- are separated by a labyrinth seal or the like. These magnetic bearings are completely oil-free construction. Note that the arrow in the figure indicates the direction in which the laser gas flows.

The second and first turbo blower can be applied to a laser oscillation device with an output of approximately IKW. Although larger turbo blades may be used to further increase the output, it is effective to use a plurality of identical turbo blades in terms of cost.

FIG. 3 shows the structure of a cube blower for a laser oscillation device with an output of about 2 kW. In the figure, 26 is a turbo blower, and since the magnetic bearings and the like are the same as in FIG. 2, they are omitted. Note that the arrow in the figure indicates the direction in which the laser gas flows.

Turbo blades 16 and 27 are provided above and below the wing l-. Here, since magnetic bearings are expensive, it is advantageous in terms of cost I to increase only the number of turbo blades without increasing the number of magnetic bearings. 17 is a rotor, and 18 is a stake.

Here, by attaching the turbo blades to the same shirt l-, load fluctuations in the thrust direction are canceled out, and the thrust load becomes only a constant weight load, which has the advantage of increasing stability.

FIG. 4 shows the structure of a turbo blower with a laser output of about 4 kW. In V, 28 is a turbo blower, and has a structure in which two turbo blowers shown in the third review are arranged in parallel. In the figure, the turbo blades 16 and 27 are driven by motors 17a and 18a, and the turbo blades 29 and 30 are driven by motors 171] and 18bT:. In the figure, the magnetic bearing is omitted. Note that the circular arrow indicates the direction in which the laser gas flows.

In the present invention, the parts other than the turbo blower 15 are the same as the configuration shown in FIG.
%, the heat of compression is reduced by that amount, and the downstream cooler can be omitted or can be much smaller than when using a Roots blower.

If the material of the turbo blower's turbo blades is made of a heat-resistant abrasive material such as ceramic, the cooler 8 can be omitted, and if a cooler with the same capacity as the cooler 8 is installed in the latter stage (at the position of the cooler 7 in Figure 5). good.

The present invention is particularly useful for high frequency discharge pumped CO□ lasers. In the case of DC discharge excitation, it is necessary to generate turbulence in the gas flow in order to obtain a uniform discharge, so the blower is required to have a high compression ratio, and the Roots blower is most suitable for this purpose. On the other hand, crystal frequency discharge excitation does not require turbulent flow, and the features of turbo blowers such as low compression ratio and large airflow capacity are effective.

Magnetic bearings have a feature called self-balancing, which allows them to rotate at high speeds without vibration.

Here, the gas replacement device was left as is, but if airtightness and other improvements are made, it is also possible to operate in a gas-sealed type operation.

〔Effect of the invention〕

As explained above, in the present invention, since the blower is a turbo blower, the blower can be downsized, its weight can be reduced, and the entire device can be downsized. Further, by reducing the number of parts, it is possible to reduce the loss of the device by one. Additionally, blower efficiency is increased, operating costs are reduced, gas displacement is reduced, operating costs are reduced, scum pulsation is eliminated, and laser output fluctuations are eliminated.

Further, since the bearing is a magnetic bearing, there is no contamination of the optical components by the oil component of the lubricating oil, and deterioration of the laser output and beam characteristics can be prevented. Furthermore, there is no vibration,
Beam characteristics such as Bointenks stability and high-speed output stability are improved.

Moreover, lubrication of the pump becomes unnecessary and maintenance is simplified.

Since the turbo blades are configured so that the thrust loads are applied in opposite directions, the thrust loads cancel each other out, increasing stability.

[Brief explanation of the drawing]

Fig. 1 is an overall configuration diagram of an embodiment of the laser oscillation device of the present invention, Fig. 2 is a structural diagram of a turbo blower with a laser output of about IKW, Fig. 3 is a structural diagram of a turbo blower with a laser output of about 2 KW, and Fig. 4 5 is a structural diagram of a turbo blower with a laser output of 4 KW, and FIG. 5 is a structural diagram of a conventional C02 laser oscillation device. 1----------1--Discharge tube 2---Output coupling mirror 3--1--Total reflection mirror 4.5-- 1------Electrode 6------------High frequency power supply 7.8---
-------- Cooler 9 -------- Roots blower 10 -----
- -To gas cylinder 12-----------Vacuum pump 13-------- Laser beam optical axis in resonator 14-------------Resonator Outer laser beam optical axis 1, 5------Turbo blower 16---
--------Turbo blade 17.18---------Motor 19.20
-----------Magnetic axis control coil 21------
-------- Metal disc 22.23------
--- Magnetic bearing control coil 24 ---
- Metal disc 25------=----Sensor 26---- Cubo blower 27----
-----Turbo blade 28---1------1 turbo blower 29.30---
−−−−−−−−Turbo blade 31−−−−−−−−−Bulkhead patent applicant Fananku Co., Ltd. agent Patent attorney Takeshi Hattori Figure 5

Claims (11)

[Claims] (1) In a gas laser oscillation device that has a discharge tube that excites the laser by gas discharge, an optical resonator that performs laser oscillation, etc., the blower is configured with a turbo blower, and the bearing of the blower is configured with a uniaxially controlled magnetic field in the thrust direction. A laser oscillation device characterized by being a bearing. (2) The laser oscillation device according to claim 1, wherein the turbo blower is composed of one turbo blade. (3) The laser oscillation device according to claim 1, wherein the turbo blower has two turbo blades that are provided so that thrust loads are applied in opposite directions to the same shaft. (4) The laser according to claim 1, wherein the turbo blower includes units having two turbo blades arranged in parallel so that thrust loads are applied to the same shaft in opposite directions. Oscillation device. (5) The laser oscillation device according to claim 3 or 4, wherein the turbo blades of the turbo blower have the same size. (6) The laser oscillation device according to claim 1, wherein the magnetic bearing is provided with a thrust bearing magnetic bearing having electromagnets at two positions, upper and lower. (7) The laser oscillation device according to claim 1, wherein one of the two upper and lower magnetic bearing positions is a thrust bearing magnetic bearing having an electromagnet, and the other position is a radial bearing with a permanent magnet. (8) The laser oscillation device according to claim 1, wherein the turbo blades of the turbo blower are made of ceramic. (9) The laser oscillation device according to claim 1, wherein the turbo blades of the turbo blower are centrifugal blades. (10) The laser oscillation device according to claim 1, wherein the turbo blades of the turbo blower are mixed flow blades. (11) The laser oscillation device according to claim 1, wherein the turbo blades of the turbo blower are axial flow blades.