JP2557264B2 - Method and apparatus for cooling fan bearing of blower unit for laser oscillator - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling method and apparatus for fan bearings of a blower unit in a laser oscillator cylinder.

2. Description of the Related Art Generally, a laser oscillator is provided with a blower unit for circulating a mixed gas for laser oscillation in a cylinder.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention A fan of a blower unit is a bearing 4 in which a rotating shaft end of a blower unit 1 or 2 is provided in a bearing housing 3 as shown in FIG.
It is supported by. The bearing 4 is often used in an exposed state as shown in a limited space. This bearing 4 is exposed to a high temperature and dilute mixed gas flow for laser oscillation of about 200 ° C. and its temperature rises. Further, the bearing itself generates heat due to the rotation of the fan, but no cooling means is provided. And the grease in the sealed lubricant evaporates. Further, since the environment around the bearing in the oscillator cylinder is set to a medium vacuum, the degree of evaporation becomes remarkable, and the bearing life becomes extremely short.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art, and an object thereof is to provide a fan bearing cooling method and device for a blower unit, which protects the bearing from high temperature gas and extends its life. Is what you are trying to do.

Means for Solving the Problems In order to achieve the above-mentioned object, the present invention ejects a low-temperature gas flow of the same kind as the mixed gas for laser oscillation but with a slightly higher pressure to the front surface of the bearing portion of the blower unit to generate high-temperature laser oscillation. A low temperature layer is formed between the mixed gas and the bearing. That is, a jet nozzle facing the downstream side is provided upstream of the mixed gas flow for laser oscillation of the bearing housing of the blower unit, and a low temperature gas having a slightly higher pressure like the mixed gas for laser oscillation is jetted from the jet nozzle.

Action When low-temperature gas for cooling is blown out from a large number of jet nozzles, the gas pressure is slightly higher than that of the mixed gas for laser oscillation, so high-temperature boundary layers are formed on both sides of the bearing, and direct contact with the bearing of the mixed gas for high-temperature laser oscillation is performed. The contact is blocked and the gas temperature further decreases due to the expansion of the gas, which cools the bearing.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

A rotary shaft 12 of a fan 11 of the blower unit is supported by a bearing 14 fitted in a bearing housing 13 fixed to the oscillator cylinder. In this example, three blind passages 15 are provided in parallel with the laser oscillation mixed gas flow B in a portion of the bearing housing 13 upstream of the laser oscillation mixed gas flow. This channel
One end of 15 is connected to a gas cylinder provided outside by a pipe line (not shown). This gas is of the same type as the laser oscillation mixed gas, has a slightly higher pressure than the laser oscillation mixed gas, and is kept at a low temperature. Further, near the blind end of the flow path 15, a large number of nozzles 16 distributed in a plane on both sides of the bearing housing 13 and directed to the downstream side of the mixed gas flow for laser oscillation are branched and formed in a branch shape. A high-temperature laser mixed gas is circulated in the laser oscillator cylinder at a gas pressure of about medium vacuum.

In such a structure, when the low temperature gas C having a pressure higher than the mixed gas pressure for laser oscillation is fed into the flow path 15 from the gas cylinder (not shown) at high speed by the fan 11 of the blower unit, the nozzles 16 on both sides are supplied with the gas. The jetted low temperature gas C forms a temperature boundary layer A on both sides of the bearing 14. Since the pressure of the low temperature gas C is slightly higher than the pressure of the high temperature laser oscillation mixed gas, the high temperature laser oscillation mixed gas is prevented from directly contacting the bearing 14 to protect the bearing 14.
The low-temperature gas C expands in a medium vacuum atmosphere to further lower the temperature, cool the bearing housing 13 and the bearing 14, and dissipate the heat by heat conduction to suppress the rise in the bearing temperature. . When the pressure of the low temperature gas C drops, the low temperature gas C is mixed with the high temperature mixed gas for laser oscillation. However, since the same kind of gas is used, no problem occurs. It is also possible to form the nozzle 16 so as to be repellant and attach it to both surfaces of the bearing housing.

Effects Since the present invention is configured as described above, it has the following effects.

According to the method of claim 1 and the device of claim 2, direct cooling of the bearing by the low temperature gas and direct contact with the bearing of the high temperature gas by the temperature boundary layer are prevented, the rise of the bearing temperature is suppressed, and the evaporation of the lubricant is prevented. The bearing life can be extended to a small extent.

In the apparatus according to the third aspect, the temperature boundary layer can be reliably formed.

[Brief description of drawings]

FIG. 1 is an explanatory partial sectional view showing a bearing portion and a nozzle portion of the present invention, FIG. 2 is a diagram showing a distribution state of a low temperature gas layer, and FIG. 3 is an explanatory partial sectional view showing a conventional bearing portion. is there. 11 …… Huan, 13 …… Bearing housing 14 …… Bearing, 15 …… Flow path 16 …… Nozzle, A …… Temperature boundary layer B …… Direction of mixed gas flow for high temperature laser oscillation.

Claims (3)

(57) [Claims] 1. A low temperature layer between the high temperature laser mixed gas mixture and the bearing is formed by jetting a low temperature gas flow of the same kind as the laser mixed gas mixture but slightly higher pressure to the front surface of the bearing portion of the blower unit of the laser oscillator. A method for cooling a fan bearing of a blower unit for a laser oscillator, the method comprising: forming a fan bearing. 2. In a laser oscillator, a nozzle housing (14) of a blower unit is provided in a bearing housing (14) of the blower unit, the nozzle (16) facing the upstream side and the downstream side of the mixed gas flow for laser oscillation (B) at least substantially in the width of the bearing. Arranged in the nozzle (16)
A fan bearing cooling device for a blower unit for a laser oscillator, characterized in that a device for supplying a low temperature gas of the same kind as the mixed gas for laser oscillation and having a slightly higher pressure is provided. 3. A fan bearing cooling device for a blower unit for a laser oscillator according to claim 2, wherein the nozzle (16) is branched from a plurality of main channels (15) in a branch shape.