JPH0351517A - High speed bearing and turboblower for laser using high speed bearing and laser transmitter - Google Patents

Abstract

PURPOSE:To supply oil in stable manners to the inside of a bearing and improve the life of the bearing by projecting a retainer for holding a rolling body having a spherical or roller shape which rotates on a rolling wheel, from the edge surfaces of an inner wheel and an outer wheel. CONSTITUTION:A rolling wheel is constituted of an inner wheel 5b and an outer wheel 5a. A rolling body 5c having a spherical or roller shape rolls on the rolling wheel, nipped by the inner wheel 5b and the outer wheel 5a. A retainer 5d holds the rolling body. The retainer 5d projects from the edge surfaces of the inner wheel 5b and the outer wheel 5a. Oil is supplied onto a transmission body and the inside of the rolling wheel through the transfer on the retainer 5d by supplying oil onto the projection part. Therefore, the life of a bearing can be improved, and the turboblower can be operated for a long period.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to high-speed bearings used in turbo blowers, turbo molecular pumps, main shafts of machine tools, etc., and in particular improves the lubricity of the bearings and extends the life of the bearings. The present invention relates to a high-speed bearing with improved reliability and maintainability, and a laser turbo blower and laser oscillation device using the same.

[Conventional technology]

Recent carbon dioxide (C02) gas laser oscillators can obtain high output and provide good quality laser beams, and are now widely used for laser processing such as cutting metal or non-metallic materials, welding metal materials, etc. ing. In particular, CNC (
As a CNC laser processing machine combined with a numerical control device,
It is rapidly developing in the field of cutting complex shapes at high speed and with high precision.

A conventional carbon dioxide (C◯2) gas laser oscillation device will be described below with reference to the drawings.

FIG. 5 is a diagram showing the overall configuration of a carbon dioxide (C◯2) gas laser oscillation device according to the prior art. An optical resonator consisting of an output coupling mirror 32 and a total reflection mirror 33 is installed at both ends of the discharge tube 31.

Metal electrodes 34 and 35 are attached to the outer periphery of the discharge tube 31. The metal electrode 34 is grounded, and the metal electrode 35
is connected to a high frequency power source 36.

A high frequency voltage is applied between the metal electrodes 34 and 35 from a high frequency power supply 36. As a result, a high frequency glow discharge is generated within the discharge tube 31, and laser excitation is performed.

The optical axis of the laser beam inside the discharge tube 31 is denoted by 43, and the optical axis of the laser beam taken out from the output coupling mirror 32 is denoted by 4.
4 respectively.

When starting up such a gas laser oscillation device, first the entire gas inside the device is exhausted by the vacuum pump 42. Then, the valve 41 is opened, a predetermined flow rate of laser gas is introduced from the gas cylinder 40, and the gas pressure within the apparatus reaches a predetermined value. Thereafter, evacuation by the vacuum pump 42 and introduction of supplementary gas by the valve 41 continue, and part of the laser gas is continuously replaced with fresh gas while the gas pressure inside the device is maintained at a specified value. This prevents gas contamination within the device.

Furthermore, in FIG. 5, the laser gas is circulated within the apparatus by a blower 39. Its purpose is to cool the laser gas. In a carbon dioxide (C○2) gas laser, about 20% of the injected electrical energy is converted into laser light, and the rest is consumed for gas heating. However, according to theory, the laser oscillation gain is proportional to the -(3/2) power of the absolute temperature T, so in order to increase the oscillation efficiency, it is necessary to forcibly cool the laser gas.

In this device, the laser gas passes through the discharge tube 31 at a flow rate of about 100 m/sec, flows in the direction shown by the arrow, and passes through the cooler 38.
guided by. The cooler 38 mainly removes heating energy due to discharge from the laser gas. And the blower 39
compresses the cooled laser gas. The compressed laser gas is guided to the discharge tube 31 via the cooler 37. This is because the compression heat generated by the blower 39 is removed by the cooler 37 before being guided to the discharge tube 31 again. Since these coolers 37 and 38 are well known, detailed explanation will be omitted.

FIG. 6 shows the structure of a turbo blower used as the blower 39. The turbo blade 1 and the shaft 2 are mechanically coupled. A rotor 3 is attached to the shaft 2, and the rotor 3 and stator 4 constitute a high frequency motor. The turbo blade 1 is rotated at a high speed of about 100,000 PPM by this high frequency motor. Therefore, compared to a Roots blower that rotates at low speed, the volume is smaller in inverse proportion to the rotation speed.

Furthermore, rolling bearings 5 and 6 are used to support the shaft 2. Normally, the high speed limit of grease lubrication is bearing 5
and the inner diameter of 6 and the Dm-N value. Dm is the average value of the inner diameter and outer diameter of the bearing, and N is the rotation speed. This D
Regarding the m-N value, a smaller inner diameter of the bearing is advantageous for high-speed rotation. For example, for a bearing with an inner diameter of 6 mm, the Dm-N value is 170.
1,500,000 Cmm/rpm), and 1,500,000 Cmm/rpm for an inner diameter of 8 mm.
mm-r pm:l, 1.4 million m for inner diameter 10 mm
m・rpm].

In addition, since loads such as centrifugal force and dead weight due to unbalance of the rotating part act on the bearing, it is not possible to use a bearing that is too small in terms of rigidity.

Therefore, currently, bearings with an inner diameter of 8 mm are used.

To lubricate the rolling bearings 5 and 6, an oil supply unit 9 is used that periodically supplies oil to the bearings in order to prevent contamination of the optical components.

In FIG. 6, a supply unit 9 supplies oil to the interior of the turbo blower via a conduit 10. Inside the turbo blower, a rolling bearing 5 is connected via passages 11 and 12.
Oil is supplied to the inside of and 6. The oil that has passed through the bearings 5 and 6 is returned to the supply unit 9 via the conduit 13.

Although not shown, the supply unit 9 is composed of a pump for delivering oil, a tank for storing oil, a filter for removing dust from the oil, and the like.

With this configuration, laser gas is drawn from the cooler 38 to the laser turbo blower as shown by arrow 8, and is discharged from the laser turbo blower to the cooler 37 as shown by arrow 7.

High-speed rotation bearings are required not only in the above-mentioned laser turbo blowers but also in turbomolecular pumps, main shafts of machine tools, etc. due to demands for higher performance and efficiency. Jet engines for aircraft with a D-N value of 3 million are in practical use.

The D-N value is the inner diameter of the bearing D (mm) x rotation speed N (r
pm). This DN value is proportional to the circumferential speed of the bearing, and it has also been found through experiments that it is proportional to the heat generation of the bearing. Instead of the inner diameter D of the bearing, the average value Dm of the inner diameter and outer diameter of the bearing may be used and expressed as a Dm-N value. The Dm-N value is approximately 1.4 times the DN value.

Oil, grease, etc. are used to lubricate such bearings, but especially at high speeds, forced oil lubrication, in which the oil is circulated by a pump, as in the laser turbo blower shown in Figure 6, or air lubrication, in which the oil is atomized, are used. Transmitted oil mist lubrication or air oil lubrication is used.

[Problem to be solved by the invention]

In a high-speed rotating blower (for example, Dm-N value of 800,000 or more), such as the conventional turbo blower for lasers shown in FIG. trying to flow into However, the centrifugal force caused by the high-speed rotation of the inner rings of the bearings 5 and 6, the retainer, and the rolling elements causes the oil to be blown away, making it impossible to provide a stable supply. As a result, seizure may occur due to insufficient lubrication.

Conversely, if the delivery pressure is increased too much and more oil is supplied than necessary, the temperature will rise due to oil friction and the q load on the motor will increase. Furthermore, since the supply of oil is not stable, there is also the problem that excess oil enters the laser gas blowing system and contaminates the laser gas.

The present invention has been made in view of these points, and an object of the present invention is to provide a high-speed bearing capable of stably supplying oil, and a laser turbo blower and laser oscillation device using the same.

[Means to solve the problem]

In order to solve the above-mentioned problems, the present invention includes: a rolling ring composed of an inner ring and an outer ring; a spherical or roller-shaped rolling element that is sandwiched between the inner ring and the outer ring and rotates on the rolling ring; A high-speed bearing comprising a cage for holding the rolling elements,
A high-speed bearing is provided, wherein the retainer protrudes from end faces of the inner ring and outer ring.

The present invention also provides a laser turbo blower comprising: a shaft having a turbo blade at its tip; a pair of bearings supporting the shaft; and a motor for rotating the shaft. There is provided a turbo blower for a laser, comprising the high-speed bearing and configured to supply oil from inside the retainer.

Furthermore, the present invention provides a laser oscillation device using the above laser turbo blower.

[Effect]

Usually, a bearing consists of a rolling ring, a rolling element, and a cage, and the cage holds the position of the rolling element, and the cage is entirely covered by the rolling ring. In the present invention, this retainer is made to protrude from the end faces of the inner ring and outer ring that constitute the rolling stock. By supplying oil to this protruding portion, the oil is transmitted through the retainer and supplied to the inside of the conductor and rolling wheel.

Therefore, even during high-speed rotation, oil can be stably supplied without being affected by centrifugal force or the like. Further, by using such a high-speed bearing in a turbo blower, the DN value increases, the high speed 1 1 limit increases, and the turbo blower can be operated for a long time.

Furthermore, by controlling the laser oscillation device using such a turbo blower, it is possible to provide a laser oscillation device that does not suffer from a decrease in output due to laser gas contamination.

〔Example〕

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

Figure 'i41 is a diagram showing a first embodiment of the laser turbo blower of the present invention. Components that are the same as those in FIG. 6 are given the same reference numerals, so a description thereof will be omitted. Here, the turbo blade 1 is shown as a centrifugal blade, but it may be a diagonal flow blade or an axial flow blade.

The essential difference between this embodiment and the conventional one is that the bearing 5
and 6, the retainers protrude from the end faces of the inner ring and the outer ring, and oil is supplied from inside the protruding retainers. That is, the retainer of the bearing 5 protrudes toward the oil inlet (toward the right side in the drawing), and the retainer of the 1 2 bearing 6 similarly protrudes toward the oil inlet (to the left in the figure).

FIG. 2 is a diagram showing an embodiment of the high-speed bearing of the present invention. In this figure, the structure of the high-speed bearing is shown together with the details of the vicinity of the oil inlet in the engineering drawing.The bearing 5 has an outer ring 5a, an inner ring 5b,
It is composed of a rolling element 5c and a cage 5d. The outer ring 5a and the inner ring 5b constitute a rolling ring. The rolling elements 5c are sandwiched between the outer ring 5a and the inner ring 5b and rotate on a rolling path. Rolling element 5c
is spherical or colo-shaped. The cage 5d holds the rolling elements 5c. In the high-speed bearing of this embodiment, the cage 5d is connected to the outer ring 5.
a and protrudes from the left end surfaces of the inner ring 5b.

The oil suction port 14 is provided inside the protrusion of the retainer 5d. Therefore, oil passes through the passage 11 and is discharged from the oil suction port 4 in the direction of the arrow 15, moves inside the bearing 5 along the inner surface of the retainer 5d, and reaches the rolling elements 5C and the rolling wheels. Furthermore, unnecessary oil moves along the inner surface of the retainer 5d and is discharged from the direction of arrow 16.

FIG. 3 is a diagram showing another embodiment of the high-speed bearing of the present invention. This embodiment is characterized by the shape of the cage 5e. That is, the retainer 5e is tapered from the protruding portion toward the rolling elements 5c. As a result, the oil discharged from the suction port 14 in the direction of the arrow l5 easily moves along the tapered inclined surface in the direction of the rolling element 5C due to the rotational centrifugal force of the bearing 5, and is further discharged in the direction of the arrow l6. be done.

FIG. 4 is a diagram showing the configuration of a second embodiment of the laser turbo blower of the present invention. In this embodiment, an oil film damper is attached around the bearings 5 and 6 of a laser turbo blower to absorb vibrations of the bearings. The oil film damper includes a sleeve 24 and O-rings 22 and 23.
and oil filled between the housing and the sleeve 24. The inner rings of the rolling bearings 5 and 6 are fixed to the shaft 2, and the outer rings are fixed to the sleeve 24. 10 between the housing and the sleeve 24
A gap of ~100 μm is provided and filled with grease or oil. ○Rings 22 and 23 are for blocking grease or oil filled in the gap from laser gas. With this configuration, vibrations caused when the turbo blades 1 and the shaft 2 rotate at high speed are attenuated by the hydrodynamic damping effect of the oil film damper.

In the above embodiments, a rolling bearing has been described, but an angular ball bearing, a cylindrical ball bearing, or a conical ball bearing may also be used. Furthermore, a ceramic bearing using ceramic such as silicon nitride as the bearing material may be used. Since this ceramic bearing is expensive, even if ceramic is used only for some of its components, for example, the rolling elements, the effect is significant.

In addition, although a pump was used in the oil supply unit 9, a turbo blower or a turbo molecular pump was set vertically, and a conical hole was formed in the center axis of the shaft, and the oil was pumped up by the centrifugal force of the shaft, and the oil was pumped up to the bearing. You can also use the sprinkling method.

Furthermore, as the material for the cage, it is desirable to use nylon, which has high self-lubricating properties and is lightweight, judging from the fact that it is used at high speed, lubricity, weight, etc. Other suitable materials include copper alloys with high self-lubricating properties and phenol resins that are easy to process.

〔Effect of the invention〕

As explained above, according to the present invention, oil can be stably supplied inside the bearing, eliminating poor lubrication.
This improves the bearing life and allows the turbo blower to operate for a longer period of time.

[Brief explanation of drawings]

Fig. 3 shows a first embodiment of the laser turbo blower of the present invention, Fig. 2 shows an embodiment of the high-speed bearing of the present invention, and Fig. 3 shows other embodiments of the high-speed bearing of the present invention. FIG. 4 is a diagram showing a second embodiment of the laser turbo blower of the present invention. FIG. 5 is a diagram showing the overall configuration of a conventional carbon dioxide (C○2) gas laser oscillation device. , FIG. 6 is a diagram showing the configuration of a conventional laser turbo blower. 22, 1 2, Turbo blade shaft Rotor stator bearing Outer ring Inner ring Rolling element retainer Oil supply unit 13 Oil conduit Oil supply port ○Ring sleeve Discharge tube 1 7 34, 37, Output coupling mirror Total reflection mirror Electrode High frequency power supply Cooler Blower Gas cylinder Vacuum pump Laser beam optical axis inside the resonator Laser beam optical axis outside the resonator

Claims (8)

[Claims] (1) A rolling ring composed of an inner ring and an outer ring, a spherical or roller-shaped rolling element that is sandwiched between the inner ring and the outer ring and rotates on the rolling ring, and a cage that holds the rolling element. A high-speed bearing comprising: The retainer protrudes from end faces of the inner ring and outer ring. (2) The high-speed bearing according to claim 1, wherein the retainer is tapered from the protruding portion toward the rolling element. (3) The high-speed bearing according to claim 2, wherein only the inner side of the cage is tapered. (4) The high-speed bearing according to claim 1, wherein the bearing is an angular contact ball bearing. (5) The high-speed bearing according to claim 1, wherein the bearing is a ceramic bearing. (6) A laser turbo blower comprising a shaft having a turbo blade at the tip, a pair of bearings supporting the shaft, and a motor for rotating the shaft, wherein the pair of bearings is A turbo blower for a laser, comprising the high-speed bearing according to item 1, and configured to supply oil from inside the retainer. (7) The turbo blower for a laser according to claim 6, wherein the bearing is provided with an oil film damper. (8) A laser oscillation device comprising a discharge tube that excites the laser by gas discharge, an optical resonator that causes laser oscillation, and a gas circulation device that forcibly cools the laser gas using a blower and a cooler, wherein the blower is A laser oscillation device comprising the laser turbo blower according to claim 6.