JPH07211964A - Turboblower for laser - Google Patents

Abstract

PURPOSE:To sufficiently cool oil when the shaft of a turboblower for laser which forcibly circulates a laser gas into a gas laser device is cooled with the oil. CONSTITUTION:The oil in a shaft supporting section 20 is sucked up from an oil inlet 130 by utilizing a centrifugal force generated when a shaft 2 is rotated and discharged from oil outlets 131 after passing through a cooling oil passage 13 in the shaft 2. Then the oil enters an oil reservoir 18 through an oil returning passage 15 while the oil is cooled by cooling water in a cooling water passage 19 and returns to the section 20 through an oil passage 180 and through port 201. A cooling water passage 22 is formed on the bottom side of the oil reservoir 18 so as to cool the oil in the reservoir 18. Since the oil stays in the reservoir 18 for a relatively long period during the circulation, the oil can be sufficiently cooled with a high efficiency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser turbo blower for forcibly circulating a laser gas in a gas laser device, and more particularly to a laser turbo blower in which bearings are lubricated with oil.

[0002]

_2. Description of the Related Art Recent high-speed axial-flow type carbon dioxide gas laser devices (CO ₂ gas laser oscillators) are compact and have high output, and have good laser beam quality, cutting metal materials and non-metal materials, metal materials, etc. It has been widely used for laser processing such as welding. In particular, as a CNC laser processing machine combined with a CNC (numerical control device), it is rapidly developing in the field of cutting complex shapes at high speed and with high accuracy.

In the carbon dioxide laser device, about 20% of the injected electric energy is converted into laser light, and the other is consumed for heating the laser gas. On the other hand, theoretically, the laser oscillation gain is proportional to the absolute temperature T to the power of − (3/2). Therefore, in order to increase the oscillation efficiency, it is necessary to forcibly cool the laser gas and lower the laser gas temperature as much as possible. Therefore, in the high-speed axial flow type carbon dioxide laser device, a laser turbo blower is used to forcibly circulate the laser gas in the device and send it to the cooler.

FIG. 3 is a diagram showing the configuration of a conventional laser turbo blower. In the figure, laser turbo blower 1
00A is installed vertically, the laser gas is sucked in as indicated by an arrow 9A, divided into two directions as indicated by an arrow 10A, and discharged in the centrifugal direction. The two directions finally become one and flow into the cooler.

With the vertical installation of the laser turbo blower 100A, the shaft 80 also becomes vertical.
To support the shaft 80, a pair of rolling bearings 50 and 60 are provided on both sides of the high frequency motor 300. By the way, there are various methods for supplying the lubricating oil to the rolling bearings 50 and 60, but here, the shaft 80 is used.
A method of supplying by utilizing the centrifugal force associated with the rotation of will be described.

At the lower end of the shaft 80, the shaft 8
0 is integrally provided with an oil suction head 47, and the lower end of the oil suction head 47 has an oil sump 48.
Is in contact with oil. When the shaft 80 rotates,
The oil is passed through the oil passage 53 due to the centrifugal force caused by the rotation.
Is sucked up by the oil and discharged from the oil outlets 153 and 154. At this time, the oil is the rolling bearings 50 and 60.
To lubricate the rolling bearings 50 and 60. The discharged oil returns to the oil sump 48 through the oil return passage 55. When passing through the oil return passage 55, the oil is cooled by the cooling water flowing through the cooling water passage 79 provided along the oil return passage 55. By this cooling, the oil releases the heat generated when lubricating the rolling bearings 50 and 60. As described above, when the shaft 80 is rotating, the oil is always circulated while repeating heating and cooling.

[0007]

However, in the case of such oil circulation, it cannot be said that the oil is still sufficiently cooled, and the oil temperature tends to rise as a whole. When this tendency becomes stronger, the rolling bearing 50
And 60 were not sufficiently lubricated, and as a result, the temperatures of the rolling bearings 50 and 60 were high. For this reason,
The life of the rolling bearings 50 and 60 was shortened, and the reliability was impaired.

Further, since the oil temperature rises,
There has been a frequent problem that a part of oil vaporizes and its vapor enters the inside of the laser oscillator to contaminate and damage the optical parts essential to the laser oscillator.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a laser turbo blower capable of sufficiently cooling the oil itself when the bearing is lubricated with the oil. And

[0010]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention supplies oil in an oil reservoir to a bearing that rotatably supports a shaft having a turbo blade at its tip, and lubricates the bearing. In the turbo blower for laser configured as described above, a cooling water channel is provided in the vicinity of the oil reservoir, and the oil in the oil reservoir is cooled.

[0011]

The oil that has passed through the oil passage, absorbs heat, and has a high temperature due to the heat generated when lubricating the bearing returns to the oil reservoir. Since the cooling water passage is provided near the oil sump to allow the cooling water to flow, the oil is sufficiently cooled while remaining in the oil sump.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a diagram showing the overall configuration of a carbon dioxide gas laser device to which the laser turbo blower of the present invention is applied. In the figure, an optical resonator including an output coupling mirror 72 and a total reflection mirror 73 is installed at both ends of the discharge tube 71. Metal electrodes 74 and 75 are mounted on the outer circumference of the discharge tube 71. The metal electrode 74 is grounded and the metal electrode 75 is connected to a high frequency power supply 76. A high frequency voltage is applied from a high frequency power supply 76 between the metal electrodes 74 and 75. As a result, high frequency glow discharge is generated in the discharge tube 71 and laser excitation is performed. By the laser excitation, the discharge tube 7
A laser beam 93 is generated inside the laser beam 1, and a part of the laser beam 93 is taken out from the output coupling mirror 72 as a laser beam 94.

When activating such a carbon dioxide laser device, the gas inside the entire device is always exhausted by the vacuum pump 92 first. Then, the valve 91 is opened and a predetermined amount of laser gas is introduced from the gas cylinder 90, whereby the gas pressure in the device reaches a specified value. After that, exhaustion of the vacuum pump 92 and introduction of replenishment gas through the valve 91 continue
A part of the laser gas is continuously replaced with fresh gas while the gas pressure inside the device is kept at a specified value. This prevents gas contamination in the device.

Further, in FIG. 2, a laser target which is a blower is used.
The laser gas is circulated in the apparatus by the bob blower 100.
There is. The purpose is to cool the laser gas. carbon dioxide gas
(CO ₂) In laser, about 20% of injected electric energy
Is converted into laser light, and the rest is consumed for gas heating. When
However, theoretically, the laser oscillation gain is-(3
/ 2) It is proportional to the power, so to increase the oscillation efficiency,
It is necessary to forcibly cool the laser gas.

In this device, the laser gas is about 200 m / s.
It passes through the discharge tube 71 at a flow rate of ec or more, flows in the direction indicated by the arrow, and is guided to the cooler 78. The cooler 78 removes heating energy mainly from the discharge from the laser gas. Then, the laser turbo blower 100 compresses the cooled laser gas. The compressed laser gas is guided to the discharge tube 71 via the cooler 77. This is because the laser gas compressed by the turbo turbo blower 100 is the discharge tube 7.
This is because the heat of compression is removed by the cooler 77 before being led again to 1. Since these coolers 77 and 78 are well known, detailed description thereof will be omitted.

The laser turbo blower 100 is driven by an inverter 40. Since the rotation speed of the laser turbo blower 100 is as high as tens of thousands RPM, a high frequency inverter corresponding to the rotation speed is used as the inverter 40.

FIG. 1 is a diagram showing the configuration of a laser turbo blower of the present invention. In the figure, the laser turbo blower 100 is installed vertically, and the laser gas is sucked in from the direction of the cooler 78 (FIG. 2) as indicated by arrow 9, and is divided into two directions as indicated by arrow 10 and discharged in the centrifugal direction. The two directions finally become one and flow into the cooler 77 (FIG. 2).

As the laser turbo blower 100 is vertically installed, the shaft 2 is also vertically installed. The shaft 2 supports rotation of the turbo blade 1, both of which are mechanically connected to each other by a nut 7. A rotor 3 is fixed to the shaft 2 along its outer periphery by shrink fit. A stator 4 is provided outside the rotor 3. The stator 4 is fixed to the housing 12,
A high frequency motor 30 is configured with the rotor 3.
The turbo blade 1 is rotated by the high frequency motor 30 at a high speed of tens of thousands RPM. A pair of rolling bearings 5 are provided on both sides of the high frequency motor 30 to support the shaft 2.
And 6 are provided.

An oil passage 13 is provided inside the shaft 2 along the axial direction thereof. This oil passage 1
A plurality of oil outlets 131 of 3 are provided on the shaft 2 between the rolling bearing 5 provided adjacent to the lower end side of the turbo blade 1 and the rotor 3 fixed to the shaft 2. These oil outlets 131 are connected to the shaft 2 and the oil passage 1.
3 is a small-diameter hole provided so as to penetrate therethrough. A part of the oil discharged from the oil outlet 131 is supplied to the rolling bearing 5 and used for lubricating the rolling bearing 5.

On the lower end side of the shaft 2, an oil suction head 17 is provided integrally with the shaft 2. The oil suction head 17 is also provided with a cooling oil passage 13 penetrating therethrough. The oil suction head 17
The outer periphery is formed in a taper shape and becomes narrower toward the tip, and the oil inlet 130 of the oil passage 13 is provided at the tip.
Are formed.

An oil reservoir 18 is formed on the lower end side of the shaft 2 just below the motor 30. Also, around the lower end side of the shaft 2 and the oil suction head 17,
Cylindrical shaft support 20 integrally with the oil sump 18
Are formed. An oil passage 180 is formed in the lower portion of the oil sump 18, and the oil passage 180 is provided with a through hole 201 provided at the center of the bottom portion of the shaft supporting portion 20.
Is in communication with. The oil in the oil sump 18 enters the inside of the cylinder of the shaft support portion 20 via the oil passage 180 and the through hole 201. Further, it enters the oil passage 13 from the oil inlet 130. As a result, when stationary, the oil in the oil sump 18, the oil in the shaft support 20 and the oil in the oil passage 13 are held at the same height.

A bearing sleeve 21 is provided on the inner peripheral surface of the shaft support portion 20 so as to be slidable in the axial direction. The bearing sleeve 21 has a protruding portion 210, the upper end of the protruding portion 210 contacts the outer ring of the rolling bearing 6, and the lower end thereof contacts the spring 16. The spring 16 is provided to apply a preload to the rolling bearings 5 and 6, and is fixed to the bottom side of the shaft support portion 20 to press the protruding portion 210 of the bearing sleeve 21, and the pressing force is
It is transmitted in order to the outer ring and inner ring of the rolling bearing 6, the shaft 2, and the inner ring and outer ring of the rolling bearing 5, and supports the shaft 2 as a whole between the shaft support portion 20 and a part of the housing 12.

An oil return passage 15 is provided in the housing 12 around the stator 4 constituting the motor 30 along the longitudinal direction of the stator 4. Further, a cooling water passage 19 is provided along the oil return passage 15 in the housing 12 around it.

A cooling water passage 22 is formed in the housing 12 on the lower side of the oil sump 18. The cooling water passage 22 is for cooling the oil in the oil sump 18, and is connected to the cooling water passage 19 by a water passage not shown here.
The cooling water circulates between a cooling water circulator (chiller) (not shown) and these cooling water passages 19 and 22 to cool the oil.

In the laser turbo blower 100 having the above structure, the oil passage 1 inside the oil suction head 17 is provided.
The oil contained in 3 is pressed against the inner wall surface of the oil passage 13 by the centrifugal force caused by the rotation of the shaft 2. At this time, a component force acts on the oil along the inner wall surface in the direction of pushing up the oil. As a result, the oil is quickly sucked up, passes through the oil passage 13 inside the shaft 2, and is discharged from the oil outlet 131. A part thereof is supplied to the rolling bearing 5 and used for lubricating the rolling bearing 5. The discharged oil returns to the oil sump 18 through the oil return passage 15. Then, when passing through the oil return passage 15, it is cooled by the cooling water in the cooling water passage 19. The oil returned to the oil sump 18 enters the shaft support portion 20 again via the oil passage 180 and the through hole 201 provided in the lower part of the oil sump 18. In this way, the oil is always circulating when the shaft 2 is rotating.

As described above, the cooling water passage 22 is formed on the lower side of the oil sump 18, and the oil sump 18 is
The oil inside is cooled. Since the oil stays in the oil sump 18 for a relatively long time during its circulation, the cooling in this place is efficiently performed. Therefore, even when the cooling water in the cooling water passage 19 alone cannot sufficiently cool the oil, the oil sump 18 can sufficiently cool the water.

Further, the oil cooling by the cooling water passage 22 also cools the entire shaft supporting portion 20,
The temperature of the bearing sleeve 210 is also kept low. Therefore, the rolling bearing 6 in contact with the bearing sleeve 210 is also cooled. Therefore, the rolling bearing 6 can have a long life and its reliability can be improved.

Furthermore, by lowering the oil temperature, the amount of oil vaporized is reduced, which reduces contamination of the optical components and prolongs the life of the optical components.
High reliability can be realized.

On the other hand, a part of the oil in the shaft supporting portion 20 is pumped up along the outer circumference of the taper portion by the centrifugal force generated by the rotation of the oil suction head 17.
It is supplied to the rolling bearing 6 and used for lubrication.

In the above description, the oil flowing through the oil passage 13 is used to lubricate the rolling bearings 5 and 6, but it may be used to cool the shaft 2 and the rotor 3. In that case, the oil passage 13
Increase the inner diameter to allow more oil to flow. By doing so, the shaft 2 and the rotor 3
It is possible to dissipate the heat generated from the oil to the oil in the oil passage 13, prevent the temperature of the shaft 2 and the rotor 3 from rising, and also cool the rolling bearings 5 and 6 effectively. Therefore, it is possible to prevent the rolling bearings 5 and 6 from being damaged due to high temperature, and it is possible to extend the life of the rolling bearings 5 and 6.

In addition, the cooling water passage 22 is connected to the oil sump 18
However, it may be provided not only on the lower side of the oil sump 18 but also on the lower side of the oil passage 180.

Further, although the cooling water passage is provided on the lower side of the oil sump 18 to cool the oil with water, the lower side of the oil sump 18 may be forcibly cooled by using a fan or the like.

Further, although the centrifugal type is adopted as the turbo blade 1 of the laser turbo blower 100, a diagonal flow blade or an axial flow blade may be adopted. Further, the present invention is applied to a laser turbo blower of a type that allows oil to pass through the inside of a vertically installed shaft, but the present invention is not limited to this type and allows the oil to circulate. If it is a turbo blower for laser of the type,
It can be widely applied.

[0034]

As described above, according to the present invention, the cooling water passage is provided in the vicinity of the oil reservoir to cool the oil. Since the oil stays in the oil sump for a relatively long time during its circulation, it is possible to efficiently and sufficiently cool the oil sump.

The oil cooling by the cooling water channel also cools the bearing sleeve in contact with the bearing, and as a result, the bearing is also cooled. Therefore, the bearing can have a long life and its reliability can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing the configuration of a laser turbo blower of the present invention.

FIG. 2 is a diagram showing an overall configuration of a carbon dioxide gas laser device to which the laser turbo blower of the present invention is applied.

FIG. 3 is a configuration diagram of a conventional laser turbo blower.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 turbo blade 2 shaft 3 rotor 4 stator 5,6 rolling bearing 13 oil passage 15 oil return passage 17 oil suction head 18 oil sump 19 cooling water passage 20 shaft support (small oil chamber) 21 bearing sleeve 22 cooling water passage 130 oil inlet 131 Oil outlet

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenji Nakahara, 3580 Kobaba, Oshinomura, Minamitsuru-gun, Minamitsuru-gun, Yamanashi FANUC CORPORATION (72) Kenji Mitsui, 3580, Kobaba, Oshino-mura, Minamitsuru-gun, Yamanashi Prefecture Local FANUC Co., Ltd.

Claims (4)

[Claims] 1. A laser turbo blower in which oil in an oil reservoir is supplied to a bearing that rotatably supports a shaft having a turbo blade at its tip to lubricate the bearing, and cooling is performed near the oil reservoir. A turbo turbo blower for a laser, wherein a water channel is provided to cool the oil in the oil reservoir. 2. The turbo blower for a laser according to claim 1, wherein the cooling water passage is formed in a housing below the oil reservoir along the oil reservoir. 3. A turbo blower for a laser in which oil in an oil reservoir is supplied to a bearing that rotatably supports a shaft having a turbo blade at its tip to lubricate the bearing, and a housing around the oil reservoir is provided. A turbo blower for a laser, characterized in that the oil in the oil reservoir is cooled by air cooling. 4. The laser turbo blower according to claim 1, wherein the housing also functions as a bearing sleeve support for supporting a bearing provided on the lower portion of the shaft.