JP3684680B2 - Laser irradiation torch - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser irradiation torch.
[0002]
[Prior art]
Conventionally, a laser cladding method has been implemented as a means for repairing a concave portion caused by corrosion or the like generated on the inner surface of a pipe material such as piping.
[0003]
FIG. 3 shows an example of a laser irradiation torch used in the laser cladding method. Reference numeral 1 denotes a hollow centering metal fitting, and the centering metal fitting 1 has an inside from its tip end side (B side in FIG. 3). An optical fiber 2 that extends outward on the base end side (A side in FIG. 3) is inserted, and a YAG laser oscillator 4 that oscillates laser light 3 is connected to the base end of the optical fiber 2. It is like that.
[0004]
A flange 6 that can be inserted into a pipe member 5 such as a pipe whose inner surface is to be repaired is provided at the base end of the centering fitting 1 (A side end shown in FIG. 3). 3 is formed with a laser emission port 7 for emitting the laser beam 3 conveyed by the optical fiber 2 to the outside.
[0005]
Further, a cylindrical spacer 8 is loosely fitted to a portion of the centering fitting 1 near the base end portion of the flange 6, and the spacer 8 has a bearing 9 near the base end portion (A side shown in FIG. 3). The holding member 10 is rotatably fitted and supported via the.
[0006]
Reference numeral 11 denotes a motor support member. The motor support member 11 is integrally connected to the flange 6 and the holding member 10 and the rod 13 described above, and the tip of the spacer 8 (shown in FIG. 3). The vicinity of (B side) is rotatably supported via a bearing 12.
[0007]
Reference numeral 14 denotes a spur gear, and the spur gear 14 is coaxially fixed to the tip of the spacer 8.
[0008]
Reference numeral 15 denotes a rotation servomotor. The rotation servomotor 15 is fixed to the motor support member 11 so that an output shaft 16 thereof is parallel to the centering metal fitting 1.
[0009]
A pinion 17 is attached to the output shaft 16 of the servomotor 15 for rotation so as to mesh with the spur gear 14.
[0010]
Reference numeral 18 denotes a rotating cylinder, and the rotating cylinder 18 is loosely fitted to a portion near the distal end portion of the centering metal fitting 1 and a base end portion (A side end portion in FIG. 3) is connected to the spur gear 14. The rotational force of the rotating servo motor 15 is transmitted to the rotary cylinder 18 via the pinion 17 and the spur gear 14.
[0011]
An opening 19 is formed in a portion located near the tip end portion (A side end portion in FIG. 3) of the outer peripheral wall of the rotary cylinder 18.
[0012]
A rotation support member 20 having a hollow structure is disposed coaxially inside the rotary cylinder 18 and is rotatably attached to the tip of the centering fitting 1 via bearings 21 and 22. It is fitted.
[0013]
Further, the base end portion (A side end portion in FIG. 3) of the rotation support member 20 is fixed to the rotating cylinder 18 and can rotate in the circumferential direction together with the rotating cylinder 18 around the centering fitting 1. It is like that.
[0014]
Reference numeral 23 denotes a condensing tube, which is disposed coaxially inside the rotating tube 18 and is fixed to the tip end portion (B side end portion in FIG. 3) of the rotation support member 20. Condensing lenses 24 a and 24 b for condensing the laser beam 3 emitted from the laser emission port 7 are arranged inside the condenser tube 23.
[0015]
The condensing lenses 24a and 24b are attached to the condensing tube 23 via annular lens frames 25a and 25b fitted on the condensing lenses 24a and 24b.
[0016]
Reference numeral 26 denotes a reflection mirror. The reflection mirror 26 reflects the laser beam 3 collected by the condenser lenses 24a and 24b and goes outward from the opening 19 provided in the rotary cylinder 18. It arrange | positions in the part near the front-end | tip part (B side edge part of FIG. 3) inside the rotary cylinder 18 so that it may radiate | emit.
[0017]
In the figure, reference numeral 27 denotes a paste-like metal powder of chromium, nickel, iron, and molybdenum. It is applied with.
[0018]
Hereinafter, a procedure for finding and repairing the concave portion 28 generated on the inner surface of the pipe member 5 using the laser irradiation torch shown in FIG. 3 will be described.
[0019]
The paste-like metal powder 27 is applied substantially uniformly to the concave portion 28 on the inner surface of the tube material 5 by a remote control device such as a manipulator, and the laser irradiation torch is inserted into the tube material 5 so that both axes coincide with each other.
[0020]
At this time, when the servo motor 15 for rotation is rotated, the rotation of the output shaft 16 is transmitted to the rotating cylinder 18 via the pinion 17 and the spur gear 14, and the rotating cylinder 18 rotates in the circumferential direction to open the opening. The position 19 is displaced in the circumferential direction of the pipe material 5.
[0021]
Next, the YAG laser oscillator 4 is connected to the base end portion of the optical fiber 2, and the rotary cylinder 18 is rotated so that the opening 19 faces the recessed portion 28 to which the paste-like metal powder 27 is applied, and then the YAG laser is rotated. The oscillator 4 is activated.
[0022]
When the YAG laser oscillator 4 is operated, the laser light 3 oscillated from the YAG laser oscillator 4 passes through the optical fiber 2, the condenser lenses 24 a and 24 b, the reflection mirror 26, and the opening 19 to the paste-like metal powder 27. Irradiated, the laser light 3 melts the paste-like metal powder 27.
[0023]
Further, after the paste-like metal powder 27 is melted, when the operation of the YAG laser oscillator 4 is stopped, the melted metal is solidified integrally on the inner surface of the tube material 5 so as to cover the recessed portion 28, and thereby the recessed portion 28 is repaired.
[0024]
[Problems to be solved by the invention]
However, when the repair work of the tube material 5 by the laser cladding method as described above is continuously performed using the laser irradiation torch shown in FIG. 3, the condenser lenses 24 a and 24 b and the reflection mirror 26 are heated by the laser light 3. The beam shape of the laser beam 3 is deformed by the thermal expansion of the condenser lenses 24a and 24b and the reflection mirror 26.
[0025]
When the beam shape of the laser beam 3 to be applied to the paste-like metal powder 27 applied to the tube material 5 is deformed, the light intensity distribution of the laser beam 3 becomes non-uniform and the paste-like metal powder 27 is melted. The metal coating layer formed on the inner surface of the tube material 5 may be insufficiently melted or poor in appearance.
[0026]
The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a laser irradiation torch in which thermal expansion does not occur in a condenser lens or a reflection mirror even when laser light is emitted for a long time.
[0027]
[Means for Solving the Problems]
In order to achieve the above object, in the laser irradiation torch according to the present invention, a torch main body having an opening in the vicinity of the tip, and laser light that is disposed inside the torch main body and is incident from the base end of the torch main body to the inside. Two condensing lenses for condensing, a lens frame provided for each of the condensing lenses and inscribed in the torch body to support the condensing lens so as to be spaced from each other, and disposed inside the tip of the torch body And a reflection mirror that reflects the laser beam collected by the condenser lens and emits the laser beam to the outside of the torch body from the opening, and is closer to the base end portion than the portion where the condenser lens is provided inside the torch body. A cooling gas supply pipe that communicates with a portion located in the lens , and each lens support frame is provided with a cooling gas flow path penetrating in the laser optical axis direction .
[0028]
In the laser irradiation torch according to the present invention, the cooling gas supplied from the cooling gas supply pipe to the portion closer to the base end portion than the portion of the torch body where the condensing lens is provided is connected to the outer peripheral portion of the condensing lens and the torch. Reflection mirror while cooling the condenser lens while flowing through the cooling gas flow path provided between the inner peripheral part of the main body and further rising inside the torch main body and flowing out from the opening of the torch main body Close the mirror to cool the reflecting mirror.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0030]
1 and 2 show an example of an embodiment of a laser irradiation torch according to the present invention. In the figure, the same reference numerals as those in FIG. 3 denote the same parts.
[0031]
In the laser irradiation torch shown in FIGS. 1 and 2, in a portion located closer to the base end portion (A side in FIG. 1) than the portion where the condensing lenses 24 a and 24 b inside the rotating cylinder 18 are provided. A cooling gas supply line 29 is communicated, and a cooling gas flow path 30 is provided between the outer peripheral part of the condenser lenses 24 a and 24 b and the inner peripheral part of the condenser cylinder 23.
[0032]
The cooling gas supply line 29 passes through the peripheral walls of the rotary cylinder 18 and the condenser cylinder 23 from the outside of the rotary cylinder 18 and is more concentrated than the part where the condenser lenses 24 a and 24 b inside the condenser cylinder 23 are provided. A cooling gas supply passage 31 communicating with a portion located near the base end portion (A side in FIG. 1) of the light tube 23 and a cooling connected to one end of the cooling gas supply passage 31 that opens to the outer periphery of the rotating tube 18. The gas supply pipe body 32 is configured.
[0033]
The cooling gas supply pipe main body 32 is provided with flexibility and length margin that can follow the rotation of the rotating cylinder 18 so as not to hinder the rotation of the rotating cylinder 18.
[0034]
A cooling gas supply source (not shown) is connected to the base end portion of the cooling gas supply pipe main body 32, and the cooling gas (arrow a in FIG. 1) delivered from the cooling gas supply source is cooled. The gas supply pipe body 32 and the cooling gas supply path 31 are supplied to the inside of the light collection tube 23.
[0035]
The cooling gas flow path 30 is located at equal intervals in the circumferential direction of the condenser lenses 24a and 24b and on the lens frames 25a and 25b supporting the condenser lenses 24a and 24b on the condenser cylinder 23, and the lens frames 25a and 25b. 25 b is formed so as to penetrate through in the thickness direction, and the space between the condensing lenses 24 a and 24 b from the space below the condensing lens 24 a inside the condensing cylinder 23 by the cooling gas flow path 30. The cooling gas a can flow from the space between the condenser lenses 24a and 24b to the space above the condenser lens 24b.
[0036]
Next, the operation will be described.
[0037]
When irradiating the paste-like metal powder 27 with the laser beam 3 oscillated from the YAG laser oscillator 4 through the optical fiber 2, the condensing lenses 24a and 24b, and the reflecting mirror 26, the cooling is performed from the cooling gas supply source. A portion closer to the base end than the portion where the condensing lens 24a is provided inside the condensing tube 23 through the cooling gas supply tube main body 32 and the cooling gas supply passage 31 of the gas supply conduit 29 (the condensing lens). Argon (Ar), helium (He), carbon dioxide (CO ₂ ), etc. are supplied as cooling gas a to the lower space 24a.
[0038]
The cooling gas a supplied to the inside of the condenser tube 23 passes through the cooling gas flow path 30 provided in the lens frame 25a on the outer periphery of the condenser lens 24a from the space below the condenser lens 24a, and the condenser lenses 24a, 24a, 24b flows into the space between the condensing lenses 24a and 24b, passes through the cooling gas passage 30 provided in the lens frame 25b on the outer periphery of the condensing lens 24b, and passes above the condensing lens 24b. Spill to
[0039]
At this time, the condenser lenses 24a and 24b are cooled by the cooling gas a flowing through the inside of the condenser cylinder 23 as described above.
[0040]
Further, the cooling gas a rises inside the rotary cylinder 18 and flows along the reflection mirror 26 when flowing out from the opening 19 formed near the tip of the rotary cylinder 18, and by this cooling gas a The reflection mirror 26 is cooled.
[0041]
Moreover, the inside of the pipe material 5 becomes an inert gas atmosphere by the cooling gas a flowing out from the opening 19 to the outside of the rotary cylinder 18.
[0042]
As described above, in the laser irradiation torch shown in FIGS. 1 and 2, the cooling gas a is circulated inside the rotary cylinder 18 and the condenser cylinder 23. Therefore, when the repair work of the tube material 5 by the laser cladding method is performed, it is long. Even if the laser beam 3 is emitted over time, the condensing lenses 24a and 24b and the reflecting mirror 26 are not heated by the laser beam 3, and thermal expansion of the condensing lenses 24a and 24b and the reflecting mirror 26 occurs. Since this does not occur, the beam shape of the laser beam 3 is not deformed, the uniformity of the light intensity distribution of the laser beam 3 is maintained, and the metal coating formed on the inner surface of the tube material 5 by melting the paste-like metal powder 27. There is no lack of melting or poor appearance in the layer.
[0043]
In addition, since the inside of the tube material 5 becomes an inert gas atmosphere due to the cooling gas a flowing out of the rotating cylinder 18, no oxide is formed on the metal coating layer formed on the inner surface of the tube material 5.
[0044]
The laser irradiation torch according to the present invention is not limited to the above-described embodiment. The laser irradiation torch according to the present invention is applied to work other than the laser cladding method in the medical field or the like other than the YAG laser oscillator. Of course, various changes can be made without departing from the gist of the present invention, such as using a laser oscillator, appropriately changing the mounting position of the cooling gas supply pipe to the torch body, and the like.
[0045]
【The invention's effect】
As described above, according to the laser irradiation torch of the present invention, the following various excellent effects can be achieved.
[0046]
(1) The condensing lens and the reflecting mirror are cooled by the cooling gas supplied from the cooling gas supply pipe to the inside of the torch body, and the condensing lens and the reflecting mirror are prevented from being heated by the laser beam. In addition, the deformation of the beam shape of the laser light due to the thermal expansion of the reflection mirror does not occur, so that the uniformity of the light intensity distribution of the laser light is maintained.
[0047]
(2) The cooling gas flowing out of the main body of the torch makes the vicinity of the object to be irradiated with the laser light a cooling gas atmosphere. Therefore, when an inert gas is used as the cooling gas and it is applied to pipe repair work by the laser cladding method In this case, no oxide is formed on the metal coating layer formed on the inner surface of the tube material by melting the paste-like metal powder.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an example of an embodiment of a laser irradiation torch according to the present invention.
FIG. 2 is a view taken in the direction of arrows II-II in FIG.
FIG. 3 is a longitudinal sectional view showing an example of a conventional laser irradiation torch.
[Explanation of symbols]
3 Laser beam 18 Rotating cylinder (Torch body)
19 Opening 23 Condenser tube (torch body)
24a Condensing lens 24b Condensing lens 26 Reflecting mirror 29 Cooling gas supply pipe (cooling gas supply pipe)
30 Cooling gas flow path

Claims (1)

A torch body having an opening in the vicinity of the distal end, two condensing lenses disposed inside the torch body and condensing laser light incident on the inside from the base end of the torch body, and these condensing lenses A lens frame that is in contact with the main body of the torch so as to be spaced apart from each other and supports the condenser lens; and a laser beam that is disposed inside the tip of the torch body and is condensed by the condenser lens is reflected. A reflection mirror that emits light from the opening to the outside of the torch body, and a cooling gas supply pipe that communicates with a portion located closer to the base end than a portion where the condenser lens is provided inside the torch body, A laser irradiation torch characterized in that each lens support frame is provided with a cooling gas passage penetrating in the laser optical axis direction .

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