JP2013004826A - Gas laser oscillation device and laser beam machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser oscillation device having blowing means that can suppress damage of the blowing means to the minimum limit when the blowing means is excessively damaged by rotational energy of a rotating shaft because a bearing connected to the rotating shaft is broken due to deterioration or the like.SOLUTION: In air blowing means for blowing laser gas, a rotating portion has a rotating shaft provided with a centrifugal impeller at the tip thereof and one or more bearings connected to the rotating shaft, and a non-rotating portion comprises a scroll portion provided in proximate to the centrifugal impeller, driving means and a housing portion for holding the rotating shaft and the bearing. The spatial distance between the rotating shaft and the housing portion is set to not more than the interval between the centrifugal impeller and the scroll portion.

Description

  The present invention relates to a gas laser oscillation device and a gas laser processing machine which are mainly used for sheet metal cutting and welding.

  FIG. 4 shows an example of a schematic configuration of a conventional axial gas laser oscillator. Hereinafter, a conventional gas laser oscillation apparatus will be described with reference to FIG.

  In this figure, 1 is a discharge tube made of a dielectric material such as glass, and 2 and 3 are electrodes provided around the discharge tube. Reference numeral 4 denotes a power source connected to the electrode. Reference numeral 5 denotes a discharge space in the discharge tube 1 sandwiched between the electrodes 2 and 3. Reference numeral 6 denotes a total reflection mirror, and reference numeral 7 denotes a partial reflection mirror. The total reflection mirror 6 and the partial reflection mirror 7 are fixedly arranged at both ends of the discharge space 5 to form an optical resonator. Reference numeral 8 denotes a laser beam output from the partial reflecting mirror 7.

  An arrow 9 indicates the laser gas flow, and circulates in the gas laser oscillation device. 10 is a laser gas flow path, 11 and 12 are heat exchangers for lowering the temperature of the laser gas whose temperature has been raised by the discharge in the discharge space 5 and the operation of the blower, and 13 is a blower means for circulating the laser gas. A gas flow of about 100 m / sec is obtained in the discharge space 5 by the blowing means 13. The laser gas flow path 10 and the discharge tube 1 are connected by a laser gas introduction part 14.

  The above is the configuration of the conventional gas laser oscillation apparatus. Next, the operation will be described.

  The laser gas sent out from the air blowing means 13 passes through the laser gas flow path 10 and is introduced into the discharge tube 1 from the laser gas introduction part 14. In this state, a discharge is generated in the discharge space 5 from the electrodes 2 and 3 connected to the power source 4. The laser gas in the discharge space 5 is excited by obtaining this discharge energy, and the excited laser gas is brought into a resonance state by an optical resonator formed by the total reflection mirror 6 and the partial reflection mirror 7. Beam 8 is output. This laser beam 8 is used for applications such as laser processing.

  As the air blowing means 13, a centrifugal air blowing means is generally used. FIG. 5 shows a configuration example of a conventional air blowing means. The motor rotor 22 is coupled to a rotating shaft 23, and an impeller 24 is provided at the tip of the rotating shaft 23. A motor stator 26 is disposed coaxially with the motor rotor 22, and the motor stator 26 is fixed to the housing 25. When electric power is supplied to the motor stator 26, the motor rotor 22 is rotated by the generated rotating magnetic field, and the impeller 24 is rotated via the rotating shaft 23. A scroll 27 is disposed around the impeller 24, and the laser gas flow 9 circulates as the impeller 24 rotates.

  The rotating shaft 23 is supported in a rotatable state by bearings 28 and 29 arranged at two locations on the upper and lower sides. The rotation shaft 23 is provided with a rotation balance body 32 for adjusting the rotation balance.

  The bearing 28 is coupled to the rotating shaft 23. The structure of the air blowing means 13 is divided into a rotating part and a non-rotating part, and the rotating part is composed of the motor rotor 22, the rotating shaft 23, the impeller 24 and the bearing 28.

  The outer periphery of the bearing 28 is coupled to the housing 25 which is a non-rotating part.

  A preload is applied to the bearing 29 arranged at the lower portion by a spring 34 through a holding body 33. The spring 34 is held by a lid 35.

  The impeller 24 and the scroll 27 are arranged so that the minimum gap is about 500 μm. This is for ensuring the flow rate of the laser gas 9 efficiently. The centrifugal force is applied to the laser gas 9 by the rotation of the impeller 24, and a laser gas flow is generated from the center of rotation toward the outside. When the gap between the impeller 24 and the scroll 27 is large, the centrifugal force due to rotation cannot be sufficiently applied to the laser gas, and the flow rate of the laser gas is reduced. For this reason, it is advantageous for securing the flow rate to make this gap as small as possible.

  The gap between the impeller 24 and the scroll 27 fluctuates due to the influence of the rotational shaft runout of the rotary shaft 23, dimensional changes due to thermal expansion, component dimensional tolerances, and the like. For this reason, if the gap is made too small below the fluctuation amount, the impeller 24 and the scroll 27 come into contact with each other and are damaged. For this reason, in the conventional gas laser oscillation apparatus, a gap of about 500 μm is set as a dimension for achieving both the flow rate of the laser gas 9 and the prevention of contact between the impeller 24 and the scroll 27.

JP 2007-40115 A

  Such a conventional gas laser oscillation apparatus has the following problems.

  In order to maintain a sufficient laser output and a laser gas 9 flow rate, the rotating shaft 23 is usually rotating at a high speed of several tens of thousands of RPM. Therefore, the bearings 28 and 29 also rotate at the same high speed. Since the rotating portion and the non-rotating portion are partially in contact with each other by a ball or the like inside the bearings 28 and 29, the load due to the high speed rotation is applied. When operated for a long time, the deterioration progresses due to the wear of the contact portions inside the bearings 28 and 29, and eventually damage occurs. When the bearings 28 and 29 are damaged, the rotary shaft 23 is shaken. For this reason, the impeller 24 provided on the rotary shaft 23 is also greatly swung around, contacting the scroll 27 and being damaged.

  If the generated damage is limited only to the rotary shaft 23 and the bearings 28 and 29, it can be dealt with by exchanging only that portion, and the cost can be minimized. However, if the peripheral members such as the impeller 24 and the scroll 27 are also affected, the parts need to be replaced. Since the impeller 24 and the scroll 27 are large parts and complicated shapes, they are expensive parts. When these are replaced, very expensive costs are required.

  The blower means 13 in the conventional gas laser oscillation apparatus cannot effectively prevent the damage damage of the parts when the bearings 28 and 29 are broken, and a large part replacement cost is generated, resulting in the maintenance cost of the gas laser oscillation apparatus. There was a problem such as an increase.

  In order to solve such a problem, as in Patent Document 1, a structure has been used in which an annular body is provided around the rotating shaft to absorb the energy of rotating shaft runout when the bearing is broken. The gap with the annular body was not clearly defined, and the function as an original purpose of preventing the damage from spreading could not be effectively performed.

  In order to solve the above problems, the present invention comprises a discharge means for exciting a laser medium, a blower means for blowing a laser gas as a laser medium, and a laser gas circulation path connecting the discharge means and the blower means, The blower means is composed of a rotating part that is rotated by a driving means and a non-rotating part that does not rotate, and the rotating part includes a rotating shaft provided with an impeller at a tip and one or more bearings coupled to the rotating shaft, The non-rotating part is composed of a scroll part provided close to an impeller, the drive means, a rotating shaft, and a housing part holding a bearing, and a method of performing a pump operation as a blowing means by the rotation of the impeller A gas laser oscillation device characterized in that a spatial distance between the rotating shaft and the housing portion is equal to or smaller than a gap between the impeller and the scroll portion; A The processing machine.

  With this configuration, even when the bearing is damaged and the rotary shaft is swung, before the impeller and the scroll come into contact with each other, the portion of the rotary shaft and the housing that is less than or equal to the gap between the impeller and the scroll portion is first. Therefore, it is possible to prevent damage to the impeller and the scroll. Therefore, the cost required for replacement of parts can be kept low.

  With the configuration shown in the present invention, even when the bearing coupled to the rotating shaft is broken due to deterioration or the like, even if the inside of the blowing means is damaged by the rotational energy of the rotating shaft, such damage is suppressed to the minimum. It is possible to provide a gas laser oscillation device equipped with an air blowing means that can do this.

FIG. 3 is a cross-sectional view of the air blowing unit of the gas laser oscillation device according to the first embodiment of the present invention Cross-sectional view of the air blowing unit of the gas laser oscillation apparatus according to the second embodiment of the present invention Configuration diagram of a gas laser processing machine in an embodiment of the present invention Configuration diagram of gas laser oscillation device according to prior art Cross-sectional view of the structure of the blowing means in the gas laser oscillation device according to the prior art

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated, referring drawings.

  In the embodiments described below, the same components as those described in the related art are denoted by the same reference numerals, and description thereof is omitted. In particular, in the present invention, since the blower has a feature, the description will be given with an emphasis on the blower.

(Embodiment 1)
FIG. 1 is a configuration diagram of the air blowing means 13 of the gas laser oscillation apparatus according to the first embodiment of the present invention. By providing a plate 30 on the rotary shaft 23, a proximity portion is created between the plate 30 and the housing 25, and the distance of the proximity portion is set to a distance less than the gap 31 between the impeller 24 and the scroll 27.

  With this configuration, even when the bearings 28 and 29 are damaged and the rotary shaft 23 is shaken, the plate 30 and the housing 25 are first contacted to absorb rotational energy. Damage to the part can be prevented.

  In FIG. 1, the plate 30 is provided on the rotating shaft 23 side, but the same effect can be obtained by providing the plate 30 on the housing 25 side.

  A metal is generally used as the material of the plate 30, but a resin material or the like can also be used.

  In the gas racer oscillation device according to the present embodiment, the distance between the provided plate 30 and the proximity portion of the housing 25 is preferably set to 250 μm or less.

  Usually, the gap 31 between the impeller 24 and the scroll 27 is arranged to be about 500 μm. For this reason, if the distance between the plate 30 and the housing 25 is 500 μm or less, contact between the impeller 24 and the scroll 27 can be prevented. However, since there is actually a variation in the dimensional tolerance of the parts, the plate 30 and the housing 25 are securely connected. In order to make the contact first, it needs to be designed to be somewhat small.

  However, if it is too small, it becomes necessary to increase the dimensional accuracy of the parts and the processing cost becomes high. As a result of considering the dimensional accuracy that can be realized by a general processing method, the distance between the impeller and the scroll is ½. It is possible to achieve both cost and function most effectively. Therefore, the distance between the rotating shaft and the adjacent portion of the housing is set to 250 μm or less.

  In installing the plate 30, the most preferred form will be described. The arrangement of the plate 30 provided in the present embodiment is characterized in that it is in the vicinity of the bearing 28 that is closest to the impeller 24 in the present invention.

  The purpose of the plate 30 is to prevent contact between the impeller 24 and the scroll 27 when the bearings 28 and 29 are damaged.

  Although there are two bearings, even if the bearing 29 at a position far from the impeller 24 and the scroll 27 is damaged, the gap 31 can be maintained to some extent by the bearing 28 at a closer position.

  However, when the bearing 28 in the near position is damaged, it is difficult to maintain the gap 31 in the bearing 29 at the far position. Therefore, the plate 30 can be made to function more effectively by setting the plate 30 in the vicinity of the bearing 28 that is closest to the impeller 24.

(Embodiment 2)
A gas laser oscillation apparatus according to the second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a configuration diagram of the air blowing means 13 of the gas laser oscillation apparatus according to the present embodiment.

  In order to rotate at a high speed like tens of thousands of RPM, it is necessary to balance the balance of mass around the center of rotation. Usually, the rotation shaft 23 is provided with a rotation balance body 32 for performing the adjustment.

  The rotation balance body 32 is designed to have a larger outer diameter than the rotation shaft 23 for that purpose. Therefore, by providing the rotation balance body 32 with the role of the plate 30, it is not necessary to newly add the plate 30, and it is possible to provide a gas laser oscillation device with reduced cost.

  The rotating balance body 32 may be press-fitted into the rotating shaft 23 or may be integrated with the rotating shaft 23. In any case, the same effect can be obtained.

(Embodiment 3)
FIG. 3 is a configuration diagram of the gas laser processing machine according to the embodiment of the present invention. The laser beam 8 is guided to the condensing lens 18 provided in the torch 17 by the reflecting mirror 15, and the workpiece 16 is irradiated with the laser beam 8 condensed by the condensing lens 18 for cutting, welding, and the like. Used.

  The processed workpiece 16 is mounted on a table 19, and the processed workpiece 16 is processed into an arbitrary shape by moving the condenser lens 18 with power 20 and 21. In FIG. 2, the condenser lens 18 is moved by the powers 20 and 21, but the same effect can be obtained by connecting and moving the powers 20 and 21 to the table 19 side.

  The gas laser oscillating device and the gas laser processing machine according to the present invention suppress damage to the inside of the blowing means due to the rotational energy of the rotating shaft to a minimum even when the bearing coupled to the rotating shaft of the blowing means is damaged due to deterioration or the like. This makes it possible to reduce maintenance costs and is useful as a gas laser oscillator and gas laser processing machine with high cost performance.

DESCRIPTION OF SYMBOLS 1 Discharge tube 2, 3 Electrode 4 Power supply 5 Discharge space 7 Partial reflection mirror 8 Laser beam 9 Laser gas flow 10 Laser gas flow path 11, 12 Heat exchanger 13 Blower means 14 Laser gas introduction part 15 Reflection mirror 16 Workpiece | work 17 Torch 18 Condensing Lens 19 Table 20, 21 Power 22 Motor rotor 23 Rotating shaft 24 Impeller 25 Housing 26 Motor stator 27 Scroll 28 Bearing 29 Bearing 30 Plate 31 Gap 32 Rotation balance body 33 Holding body 34 Spring 35 Lid

Claims (6)

Discharge means for exciting a laser medium, blower means for blowing laser gas as a laser medium, and a laser gas circulation path connecting the discharge means and the blower means, the blower means rotating with a rotating part rotated by a drive means. Consists of non-rotating parts that do not perform,
The rotating part includes a rotating shaft provided with an impeller at a tip and one or more bearings coupled to the rotating shaft,
The non-rotating part is composed of a scroll part provided close to the impeller, the driving means, the rotating shaft, and a housing part that holds the bearing,
A laser oscillation device having a method of performing a pump operation as a blowing means by rotation of the impeller,
A gas laser oscillation device characterized in that a spatial distance between the rotating shaft and the housing portion is set to be equal to or smaller than a gap between the impeller and the scroll portion. The gas laser oscillation device according to claim 1, further comprising: a plate attached to the rotating shaft, wherein the portion of the rotating shaft having the narrowest spatial distance with respect to the housing portion is the plate portion. The gas laser oscillation apparatus according to claim 1 or 2, wherein a spatial distance between the rotation shaft and the housing portion is 250 µm or less. The location where the spatial distance between the rotating shaft and the housing portion is equal to or less than the gap between the impeller and the scroll portion is set in the vicinity of the bearing closest to the impeller among the one or more bearings. The gas laser oscillation apparatus in any one of Claim 1 to 3. 2. The gas laser oscillation apparatus according to claim 1, wherein a portion where a spatial distance between the rotating shaft and the housing portion is equal to or smaller than a gap between the impeller and the scroll portion is a rotation balance adjusting portion of the rotating shaft. A laser beam is generated from a processing table on which a workpiece is placed, a driving unit that moves at least one of a movement of the processing table and a laser beam condensing unit, a numerical control unit that controls the driving unit, and a laser beam. A laser processing machine comprising the laser oscillation device according to claim 4.

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