JP6420550B2 - Laser cutting device - Google Patents

Description

  The present invention relates to a laser cutting device, and more particularly to a laser cutting device that cuts a structure or a building using laser light.

Structures and structures such as nuclear reactors and bridges are being considered to be dismantled by cutting steel or concrete into lengths and sizes that are easy to handle. For cutting, a laser cutting device that is easy to handle is used. However, the conventional laser cutting device cannot cut steel, concrete, or the like far away from the head that emits laser light (see, for example, Patent Document 1). . For this reason, when disassembling a structure or building using a conventional laser cutting device, the laser cutting device is suspended by a crane and brought close to the structure or building, or the laser cutting device is driven by a self-propelled vehicle. It has been proposed to be attached to a device to be close to a structure or a building (for example, see Patent Document 2).
On the other hand, if the output can be made larger than that of conventional laser cutting devices, cutting energy can be obtained even if the distance from the head to the focal position is increased. Therefore, it is easy to handle steel or concrete several meters away from the head. Can be cut into pieces.

Japanese Patent No. 2846297 JP-A-8-262190

However, since the distance from the head to the focal position does not change just by increasing the output compared to the conventional laser cutting device, the head is moved each time steel or concrete is cut, and the steel or concrete that is cut from the head. It is necessary to keep the distance up to constant.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a laser cutting device that can arbitrarily change the focal position of laser light emitted from a head.

The present invention includes a laser oscillator that oscillates a laser beam, an optical fiber through which the laser beam oscillated from the laser oscillator propagates, and a head that emits the laser beam incident from the optical fiber to an object to be cut. In the laser cutting device, the head includes a focal position changing optical system capable of arbitrarily changing a focal position of emitted laser light.
Since the present invention has the focal position changing optical system capable of arbitrarily changing the focal position of the emitted laser light, the focal position of the laser light emitted from the head can be arbitrarily changed. Thereby, even when a structure or a building is dismantled using the laser cutting device according to the present invention, it is not necessary to move the laser cutting device every time steel material or concrete is cut.

In one aspect of the present invention, the focal position changing optical system is fixed to the emission side of the head, and is provided on the incident side of the head, and a condenser lens that collects laser light emitted from the head. A first lens that receives the laser light emitted from the optical fiber; and a movable lens provided between the condensing lens and the first lens; and the focal point of the condensing lens together with the first lens. And a second lens that changes the position.
If it does in this way, the 2nd lens can change the focal position of a condensing lens arbitrarily with the 1st lens. This eliminates the need to move the laser cutting device each time steel material, concrete, or the like is cut even when the steel material or building is dismantled.

In one aspect of the present invention, it is preferable that the first lens is fixed to the incident side of the head.
If it does in this way, the focal position of a condensing lens can be arbitrarily changed only by moving the 2nd lens.

In one aspect of the present invention, the first lens is movable on the incident side of the head, and the second lens has a predetermined relationship with the first lens and can move. This is true.
In this way, the first lens and the second lens move with a predetermined relationship, and the second lens can arbitrarily change the focal position of the condenser lens together with the first lens.

In one embodiment of the present invention, the laser oscillator preferably oscillates multimode laser light.
In this way, the laser oscillator oscillates multimode laser light, so that the required laser light intensity can be easily obtained. Thereby, the required laser beam intensity can be obtained at an arbitrary position.

In one embodiment of the present invention, it is preferable that a holder for holding the second lens is provided, and the holder has a flow path through which a coolant flows around the second lens.
If it does in this way, the 2nd lens provided between the condensing lens and the 1st lens can be cooled.

  As described above, according to the present invention, the focal position of the laser light emitted from the head can be arbitrarily changed. Thereby, when disassembling a structure or a building using the laser cutting device according to the present invention, it is not necessary to move the head every time steel or concrete is cut.

It is a schematic diagram which shows the outline | summary of the laser processing apparatus which is embodiment of this invention. It is a schematic diagram which shows the structure of the head which concerns on Embodiment 1 of this invention. It is a schematic diagram for demonstrating the focus position change optical system shown in FIG. It is a longitudinal cross-sectional view which shows the structure of the lens holder shown in FIG. FIG. 5 is a VV transverse sectional view of the lens holder shown in FIG. 3. It is a figure which shows the structure of the head which concerns on Embodiment 2 of this invention. It is a schematic diagram for demonstrating the focus position change optical system shown in FIG.

  Exemplary embodiments of a laser cutting device according to the present invention will be explained below in detail with reference to the accompanying drawings. The present invention is not limited to the embodiments.

FIG. 1 is a schematic diagram showing an outline of a laser cutting apparatus according to an embodiment of the present invention.
As shown in FIG. 1, a laser cutting device 2 according to an embodiment of the present invention is for cutting an object several meters away from a head 3 that emits laser light. The focal position of the light L can be arbitrarily changed.

  As shown in FIG. 1, a laser cutting device 2 according to an embodiment of the present invention is mounted on a self-propelled traveling device 11 and can be moved to a position suitable for emission of laser light L. The laser cutting device 2 includes a laser oscillator 21, a control device 22, an optical fiber 23, and a head 3.

  The laser oscillator 21 is for oscillating the laser light L. The laser light L includes a single mode in which the intensity distribution is large at the center and a probability distribution around the periphery, and other multi modes. The laser oscillator 21 according to the present embodiment uses an oscillator that oscillates a multimode laser beam L that is excellent in cost, but is not limited to an oscillator that oscillates a multimode laser beam L, and is a single mode laser. It may oscillate light. The laser oscillator 21 is selected arbitrarily depending on the object to be cut and the distance from the head 3 to the object to be cut (focal position). Specifically, the wavelength, maximum output, pulse width, and oscillation mode (continuous wave, pulse wave) of the laser beam L to be oscillated according to the type of the cutting objects T1 and T2 and the distance from the head 3 to the cutting objects T1 and T2. A suitable one is selected. For example, recently, a laser oscillator having a maximum output of 100 kw can be selected.

The control device 22 controls the laser oscillator 21 in an integrated manner, and controls the wavelength, output, pulse width, oscillation mode, and the like of the selected laser oscillator 21 within an adjustable range.
The optical fiber 23 is for propagating the laser beam L oscillated from the laser oscillator 21. In this embodiment, the optical fiber 23 propagates the laser beam L oscillated from the laser oscillator 21 to the head 3.
The head 3 is for condensing the laser light L propagated through the optical fiber 23 onto cutting objects T1 and T2 such as steel and concrete.

[Embodiment 1]
FIG. 2 is a schematic diagram showing the configuration of the head according to the first embodiment of the present invention, and FIG. 3 is a schematic diagram for explaining the focal position changing optical system shown in FIG. 4 and 5 are cross-sectional views showing the structure of the lens holder shown in FIG.
As shown in FIGS. 2 and 3, the head 3 according to Embodiment 1 of the present invention is formed in a cylindrical shape, and has a focal position changing optical system 4 therein. The focal position changing optical system 4 is for arbitrarily changing the focal position of the laser light emitted from the head 3, and as shown in FIG. 3, a condensing lens (group) 41, a first lens (group) ) 42 and a second lens (group) 43.

  As shown in FIGS. 2 and 3, the condensing lens 41 is a lens that is fixed to the emission side of the head 3 and condenses the laser light L emitted from the head 3. The condenser lens 41 is fixed so that its optical axis is located on an axis passing through the center of the head 3. As shown in FIG. 3, the condensing lens 41 according to Embodiment 1 of the present invention is configured by combining a meniscus lens 411 and a biconvex lens 412. In the meniscus lens 411 and the biconvex lens 412, the meniscus lens 411 is disposed on the incident side of the laser light L, and the biconvex lens 412 is disposed on the emission side of the laser light L. The meniscus lens 411 has a convex side facing the biconvex lens 412, and the laser light L is incident on the meniscus lens 411 from the concave side. In the biconvex lens 412, the side with the larger curvature radius faces the meniscus lens 411, and the laser light L enters the biconvex lens 412 from the side with the larger curvature radius.

  As shown in FIGS. 2 and 3, the first lens 42 is a lens that is fixed to the incident side of the head 3 and receives the laser light L emitted from the optical fiber 23. Similar to the condensing lens 41, the first lens 42 is fixed so that its optical axis is located on an axis passing through the center of the head 3. As shown in FIG. 3, the first lens 42 according to Embodiment 1 of the present invention is configured by combining two plano-convex lenses 421 and 422 for the purpose of reducing aberrations. Here, the plano-convex lens 421 that is the incident side of the laser beam L faces the plano-convex lens 422 whose convex side is the exit side. As a result, the laser light L enters the plano-convex lens 421 on the incident side of the laser light L from the flat side. Further, the plano-convex lens 422 on the laser light emission side faces the plano-convex lens 421 whose convex side is the incident side. As a result, the laser light L is incident on the plano-convex lens 422 on the emission side of the laser light L from the convex side.

  The second lens 43 is a lens that can move between the condenser lens 41 and the first lens 42, and changes the focal position of the condenser lens 41 together with the first lens 42 described above. is there. The optical axis of the second lens 43 moves on an axis passing through the center of the head 3 by the moving module 5 described later. The second lens 43 according to Embodiment 1 of the present invention is configured by combining a meniscus lens 431 and a biconcave lens 432. In the meniscus lens 431 and the biconcave lens 432, the meniscus lens 431 is disposed on the incident side of the laser beam L, and the biconcave lens 432 is disposed on the exit side of the laser beam L. The meniscus lens 431 has a convex side facing the biconcave lens 432, and the laser light L is incident on the meniscus lens 431 from the concave side. In the biconcave lens 432, the side with the smaller radius of curvature faces the meniscus lens 431, and the laser light L enters the biconcave lens 432 from the side with the smaller radius of curvature.

  The second lens 43 is built in the moving module 5 and moves on an axis line whose optical axis passes through the center of the head 3 as described above. The moving module 5 includes a grooved fixed inner cylinder 51, a lens holder 52, and a grooved outer cylinder 53.

  The grooved fixed inner cylinder 51 is a cylindrical guide member built in the head 3, and an axis passing through the center thereof coincides with an axis passing through the center of the head 3. The grooved fixed inner cylinder 51 is provided with a pair of guide grooves 511 having an axis passing through the center as an axis of symmetry. The guide groove 511 is parallel to an axis passing through the center of the grooved fixed inner cylinder 51.

  The lens holder 52 is for holding the second lens 43 and is formed in a cylindrical shape. The lens holder 52 is slidably fitted into the grooved fixed inner cylinder 51, and the axis passing through the center thereof coincides with the axis passing through the center of the grooved fixed inner cylinder 51. Thereby, the axis passing through the center of the lens holder 52 coincides with the axis passing through the center of the head 3. A pair of guide pins 521 having an axis passing through the center of the lens holder 52 as an axis of symmetry is provided on the outer periphery of the lens holder 52. The guide pin 521 is inserted into the guide groove 511 provided in the grooved fixed inner cylinder 51 described above, and the lens holder 52 is guided along the axial direction passing through the center of the grooved fixed inner cylinder 51.

  As shown in FIGS. 4 and 5, the second lens 43 is fitted into the lens holder 52 and sealed by O-rings 522 and 523. The optical axis passing through the center of the second lens 43 coincides with the axis passing through the center of the lens holder 52. As a result, the optical axis passing through the center of the second lens 43 coincides with the axis passing through the center of the grooved fixed inner cylinder 51 and the axis passing through the center of the head 3, and the optical axis of the condenser lens 41 and the first axis. It also coincides with the optical axis of the lens 42.

  Specifically, a meniscus lens 431 and a biconcave lens 432 constituting the second lens 43 are fitted and sealed by O-rings 522 and 523. The optical axes passing through the centers of the meniscus lens 431 and the biconcave lens 432 coincide with the axis passing through the center of the lens holder 52. As a result, the optical axis passing through the centers of the meniscus lens 431 and the biconcave lens 432 coincides with the optical axis of the condenser lens 41 and the optical axis of the first lens 42.

  As shown in FIGS. 4 and 5, a flow path 525 is provided around the meniscus lens 431 and the biconcave lens 432 constituting the second lens 43. The flow path 525 is for cooling the second lens 43, and as shown in FIG. 5, a supply port 526 communicating with the flow path 525 is provided on one of the pair of guide pins 521, and the flow path is provided on the other side. A discharge port 527 that communicates with 525 is provided. As a result, a refrigerant (for example, cooling water) is supplied from the outside of the grooved fixed inner cylinder 51 to the flow path 525 through the supply port 526 provided in the guide pin 521, and provided from the flow path 525 to the guide pin 521. The refrigerant is discharged out of the fixed inner cylinder 51 with the groove through the discharge port 527. In this way, the second lens 43 heated by condensing the laser beam L is cooled.

  The grooved outer cylinder 53 is for moving the second lens 43 along the optical axis direction of the laser beam L, and is formed in a cylindrical shape into which the grooved fixed inner cylinder 51 is fitted as shown in FIG. ing. The grooved outer cylinder 53 is attached so as to be rotatable with respect to the outer periphery of the grooved fixed inner cylinder 51 and immovable in the optical axis direction of the laser beam L.

  The grooved outer cylinder 53 is provided with a pair of operating grooves 531 having an axis passing through the center as an axis of symmetry. The operation groove 531 is formed in a spiral shape, and the pair of guide pins 521 described above are inserted into each of the operation grooves 531. As a result, the pair of guide pins 521 provided on the lens holder 52 are restrained by the guide grooves 511 provided on the grooved fixed inner cylinder 51 and the operating grooves 531 provided on the grooved outer cylinder 53, so When the tube 53 is rotated, the lens holder 52 in which the pair of guide pins 521 is restrained moves along the optical axis direction of the laser light L. As a result, the second lens 43 moves along the optical axis direction of the laser light L.

  For example, in the example shown in FIG. 2, when the grooved outer cylinder 53 is rotated clockwise, the second lens 43 approaches the condenser lens 41, and the focal position of the laser light L emitted from the condenser lens 41 is Move away from the back. On the other hand, when the grooved outer cylinder 53 is rotated counterclockwise, the second lens 43 approaches the first lens 42, and the focal position of the laser light L emitted from the condenser lens 41 approaches the near side.

  The grooved outer cylinder 53 may be rotated clockwise or counterclockwise by manual operation. However, a drive source such as a motor for rotating the grooved outer cylinder is provided, and the grooved outer cylinder 53 is controlled by the control device 22 described above. It is good also as what rotates by instruction | command.

  In the laser cutting device 2 according to the first embodiment of the present invention described above, the laser light L emitted from the emission end of the optical fiber 23 is incident on the first lens 42 while spreading. Then, the laser beam L that has passed through the first lens 42 enters the second lens 43 while being narrowed. The laser light L that has passed through the condenser lens 41 is condensed at a focal position (for example, T1 in FIG. 1) while narrowing.

  When the focal position of the laser beam L is moved away from this state, the grooved outer cylinder 53 is rotated clockwise in FIG. Thus, when the grooved outer cylinder 53 is rotated clockwise, the second lens 43 approaches the condenser lens 41, and the laser light L that has passed through the condenser lens 41 has the above-described focal position (for example, FIG. 1). In FIG. 1 (for example, T2 in FIG. 1). Thereby, the focal position moves away from the back side.

  On the other hand, when the focal position of the laser beam L is brought closer to the near side from this state, the grooved outer cylinder 53 is rotated counterclockwise in FIG. When the grooved outer cylinder 53 is rotated counterclockwise in this way, the second lens 43 approaches the first lens 42, and the laser light L that has passed through the condenser lens 41 has the above-described focal position (for example, The light is condensed on the near side (for example, T1 in FIG. 2) from T2 in FIG. Thereby, the focal position approaches the near side.

  Since the laser cutting device 2 according to the first embodiment of the present invention described above has the focal position changing optical system 4 that can arbitrarily change the focal position of the emitted laser light L, the laser cutting apparatus 2 The focal position can be changed arbitrarily. Thereby, even when a structure or a building is dismantled using the laser cutting device 2 according to the first embodiment of the present invention, it is not necessary to move the laser cutting device 2 every time steel material or concrete is cut. .

  In addition, in the focal position changing optical system 4 according to Embodiment 1 of the present invention, the second lens 43 can arbitrarily change the focal position of the condenser lens 41 together with the first lens 42. Thereby, it is not necessary to move the laser cutting device 2 every time steel material or concrete is cut.

  Further, since the laser oscillator 21 according to the first embodiment of the present invention oscillates the multimode laser light L, the necessary laser light intensity can be easily obtained. Thereby, the required laser beam intensity can be obtained at an arbitrary position.

  In addition, since the lens holder 52 according to Embodiment 1 of the present invention has the flow path 525 through which the coolant flows around the second lens 43, the lens holder 52 is provided between the condenser lens 41 and the first lens 42. The second lens 43 heated by condensing the laser beam L is efficiently cooled.

  In the focus position changing optical system 4 according to Embodiment 1 of the present invention described above, the condensing lens 41, the first lens 42, and the second lens 43 are each composed of two lenses. There is no limitation, and it is possible to increase the number of each lens to have each function.

  In the above-described focal position changing optical system 4, the flow path 525 through which the coolant flows is provided in the lens holder 52 that holds the second lens 43 to cool the second lens 43. Also, a flow path through which the refrigerant flows can be provided around the first lens 42 to cool both the condenser lens 41 and the first lens 42.

  Further, the moving module 5 described above includes the grooved fixed inner cylinder 51, the lens holder 52, and the grooved outer cylinder 53, but is not limited thereto. For example, the lens holder 52 includes a linear guide, a ball screw, and the like. You may comprise by combining. In this configuration, the lens holder 52 is guided by a linear guide and can move in the optical axis direction of the laser light L, and further sent to a ball screw to move in the optical axis direction of the laser light L. Further, a drive source such as a motor for rotating the ball screw clockwise or counterclockwise may be provided and rotated by a command from the control device 22 described above.

  In addition, a distance measuring means such as a distance meter for measuring the distance to the cutting objects T1 and T2 is provided, the distance to the cutting objects T1 and T2 is measured, and the focal position of the laser beam L is changed based on the measurement result. It is good to do.

  Further, assist gas injection means for injecting assist gas to the cutting objects T1 and T2 on which the laser beam L is condensed is provided, and when the cutting objects T1 and T2 are cut with the laser beam L, the assist gas is injected and cut. It is good also as what assists.

[Embodiment 2]
FIG. 6 is a diagram showing the configuration of the head according to Embodiment 2 of the present invention, and FIG. 7 is a schematic diagram for explaining the focal position changing optical system shown in FIG.
As shown in FIGS. 6 and 7, the head 3 according to the second embodiment of the present invention is formed in a cylindrical shape and has a focal position changing optical system 6 therein. The focal position changing optical system 6 is for arbitrarily changing the focal position of the laser light L emitted from the head 3, and as shown in FIG. 7, a condensing lens (group) 61, a first lens ( Group) 62 and a second lens 63.

  As shown in FIGS. 6 and 7, the condensing lens 61 is a lens fixed on the emission side of the head 3 and is for condensing the laser light L emitted from the head 3. The condenser lens 61 is fixed so that its optical axis is located on an axis passing through the center of the head 3. As shown in FIG. 7, the condensing lens 61 according to Embodiment 2 of the present invention is configured by combining two plano-convex lenses 611 and 612 having a long focal length. Here, the plano-convex lens 611 on the incident side of the laser beam L faces the plano-convex lens 612 on the convex side on the exit side. Thereby, the laser beam L is incident on the plano-convex lens 611 on the incident side of the laser beam L from the plane side. Further, the plano-convex lens 612 on the laser beam L emission side faces the plano-convex lens 611 on which the plane side is the incident side. As a result, the laser light L is incident on the plano-convex lens 611 on the emission side of the laser light L from the flat side.

  As shown in FIGS. 6 and 7, the first lens 62 is a lens that is movable on the incident side of the head 3, and is for receiving the laser light L emitted from the optical fiber 23. The first lens 62 is moved on an axis whose optical axis passes through the center of the head 3 by the moving module 7 described later. As shown in FIG. 7, the first lens 62 according to Embodiment 2 of the present invention is configured by combining two of a plano-convex lens 621 and a biconvex lens 622 for the purpose of reducing aberrations. In the plano-convex lens 621 and the biconvex lens 622, the plano-convex lens 621 is disposed on the incident side of the laser beam L, and the biconvex lens 622 is disposed on the exit side of the laser beam L. The plano-convex lens 621 has a convex side facing the biconvex lens 622, and the laser light L is incident on the plano-convex lens 621 from the flat side. On the other hand, in the biconvex lens 622, the incident side and the emission side have substantially the same shape, and the light incident from the incident side is condensed on the emission side.

  The second lens 63 is a lens that can move between the condenser lens 61 and the first lens 62, and changes the focal position of the condenser lens 61 together with the first lens 62 described above. is there. Similarly to the first lens 62 described above, the second lens 63 is moved on an axis whose optical axis passes through the center of the head 3 by the moving module 7 described later. The second lens 63 according to Embodiment 2 of the present invention is composed of a plano-concave lens 631. In the plano-concave lens 631, the concave side faces the incident side of the laser beam L. Thereby, the laser light L enters the plano-concave lens 631 from the concave side.

  The first lens 62 and the second lens 63 are built in the moving module 7, and the optical axis thereof moves on the axis passing through the center of the head 3 as described above. The moving module 7 includes a grooved fixed inner cylinder 71, a first lens holder 72, a second lens holder 73, and a grooved outer cylinder 74.

  The grooved fixed inner cylinder 71 is a cylindrical guide member built in the head 3, and an axis passing through the center thereof coincides with an axis passing through the center of the head 3. The grooved fixed inner cylinder 71 is provided with a pair of guide grooves 711 having an axis passing through the center as an axis of symmetry. The guide groove 711 is parallel to an axis passing through the center of the grooved fixed inner cylinder 71.

  The first lens holder 72 is for holding the first lens 62 and is formed in a cylindrical shape. The first lens holder 72 is slidably fitted into the grooved fixed inner cylinder 71, and the axis passing through the center thereof coincides with the axis of the grooved fixed inner cylinder 71. Thereby, the axis passing through the center of the first lens holder 72 coincides with the axis passing through the center of the head 3. A pair of guide pins 721 having an axis passing through the center of the first lens holder 72 as an axis of symmetry is provided on the outer periphery of the first lens holder 72. The guide pin 721 is inserted through the guide groove 711 provided in the above-described grooved fixed inner cylinder, and the first lens holder 72 is guided along an axis passing through the center of the grooved fixed inner cylinder 71.

  Similar to the lens holder 52 according to the first embodiment of the present invention described above, the first lens 62 is fitted into the first lens holder 72, and the optical axis passing through the center thereof is the center of the first lens holder 72. Coincides with the axis passing through. Thereby, the optical axis passing through the center of the first lens 62 is positioned as an axis passing through the center of the grooved fixed inner cylinder 71 and coincides with the optical axis of the condenser lens 61.

  Specifically, the plano-convex lens 621 and the biconvex lens 622 constituting the first lens 62 are fitted, and the optical axis passing through each center coincides with the axis passing through the center of the first lens holder 72. As a result, the optical axis passing through the centers of the plano-convex lens 621 and the biconvex lens 622 also coincides with the optical axis of the condenser lens 61.

  Similar to the first lens holder 72, the second lens holder 73 is for holding the second lens 63 and is formed in a cylindrical shape. The second lens holder 73 is slidably fitted to the opposite side of the first lens holder 72 in the grooved fixed inner cylinder 71, and the axis passing through the center thereof also coincides with the axis of the grooved fixed inner cylinder 71. As a result, the axis passing through the center of the second lens holder 73 coincides with the axis passing through the center of the first lens holder 72 and also coincides with the axis passing through the center of the head 3. A pair of guide pins 731 having an axis passing through the center of the second lens holder 73 as an axis of symmetry are provided on the outer periphery of the second lens holder 73. The guide pin 731 is inserted into the guide groove 711 provided in the grooved fixed inner cylinder 71 described above, and the second lens holder 73 is grooved similarly to the first lens holder 72. Guided along an axis passing through the center of the fixed inner cylinder 71.

  Similar to the first lens holder 72 described above, the second lens 63 is fitted into the second lens holder 73, and the optical axis passing through the center thereof coincides with the axis passing through the center of the second lens holder 73. . Thereby, the optical axis passing through the center of the second lens 63 coincides with the axis passing through the center of the grooved fixed inner cylinder 71, and also coincides with the optical axis of the condenser lens 61 and the optical axis of the first lens 62. .

  Specifically, a plano-concave lens 631 constituting the second lens 63 is fitted, and an optical axis passing through the center thereof coincides with an axis passing through the center of the second lens holder 73. Thereby, the optical axis passing through the center of the plano-concave lens 631 coincides with the optical axis of the condenser lens 61 and the optical axis of the first lens 62.

  Although not particularly illustrated, like the lens holder 52 according to Embodiment 1 of the present invention described above, the second lens holder 73 is provided with a flow path around the plano-concave lens 631 constituting the second lens 63. ing. The flow path is for cooling the second lens 63, one of the pair of guide pins 731 is provided with a supply port communicating with the flow path, and the other is provided with a discharge port communicating with the flow path. . As a result, refrigerant (for example, cooling water) is supplied to the flow path from the outside of the grooved fixed inner cylinder 71 through the supply port provided in the guide pin 731, and the discharge port provided in the guide pin 731 from the flow path. The refrigerant is discharged out of the fixed inner cylinder 71 with grooves. In this way, the second lens 63 heated by condensing the laser light L is cooled.

  The grooved outer cylinder 74 is such that the first lens 62 and the second lens 63 are along the optical axis direction of the laser light L in a state where the first lens 62 and the second lens 63 have a predetermined relationship. As shown in FIG. 6, the grooved fixed inner cylinder 71 is formed in a cylindrical shape. The grooved outer cylinder 74 is attached so as to be rotatable with respect to the outer periphery of the grooved fixed inner cylinder 71 and immovable in the optical axis direction of the laser beam L.

  The grooved outer cylinder 74 is provided with two pairs of operating grooves 741 and 742 having an axis passing through the center as an axis of symmetry. One working groove 741 (hereinafter referred to as “first working groove 741”) is provided on the incident side of the laser beam L, and the other working groove 742 (hereinafter referred to as “second working groove 742”) It is provided on the emission side of the laser beam L. The first working groove 741 and the second working groove 742 are formed to have a predetermined relationship. The first operating groove 741 is for moving the first lens 62, and is formed in a spiral shape having a steep slope. The guide pin 721 provided in the first lens holder 72 described above is inserted through each pair of the first operation grooves 741. As a result, the pair of guide pins 721 provided in the first lens holder 72 is formed in the guide groove 711 provided in the grooved fixed inner cylinder 71 and the first operation groove 741 provided in the grooved outer cylinder 74. When the outer cylinder 74 with the groove is restrained and rotated, the first lens holder 72 with the pair of guide pins 721 restrained moves along the optical axis direction of the laser light L. As a result, the first lens 62 moves along the optical axis direction of the laser light L. The second operating groove 742 is for moving the second lens 63, and is formed in a spiral shape with a gentler gradient than the first operating groove 741. The guide pins 731 provided on the second lens holder 73 described above are fitted into each pair of the second operation grooves 742. As a result, the pair of guide pins 731 provided in the second lens holder 73 are guided into the guide groove 711 provided in the grooved fixed inner cylinder 71 and the second operation groove 742 provided in the grooved outer cylinder 74. When the outer cylinder 74 with the groove is restrained and rotated, the second lens holder 73 with the pair of guide pins 731 restrained moves along the optical axis direction of the laser light L. As a result, the second lens 63 moves along the optical axis direction of the laser light L.

  Therefore, when the grooved outer cylinder 74 is rotated, the first lens holder 72 and the second lens holder 73 move with a predetermined relationship. As a result, the first lens 62 and the second lens 63 move with a predetermined relationship.

  For example, in the example shown in FIG. 6, when the grooved outer cylinder 74 is rotated clockwise, the first lens 62 and the second lens 63 approach the condenser lens 61 with a predetermined relationship, and collect the light. The focal position of the laser light L emitted from the optical lens 61 is moved away from the back side. On the other hand, when the grooved outer cylinder 74 is rotated counterclockwise, the first lens 62 and the second lens 63 are separated from the condenser lens 61 with a predetermined relationship and emitted from the condenser lens 61. The focal position of the laser beam L approaches the near side.

  The grooved outer cylinder 74 may be rotated clockwise or counterclockwise by manual operation. However, a drive source such as a motor for rotating the grooved outer cylinder 74 is provided, and the above-described control device 22 It is good also as what rotates by the instruction | command of.

  In the laser cutting device 2 according to the second embodiment of the present invention described above, the laser light L emitted from the emission end of the optical fiber 23 enters the first lens 62 while spreading. The laser light L that has passed through the first lens 62 enters the second lens 63 while narrowing. Then, the laser light L that has passed through the second lens 63 becomes substantially parallel laser light L and enters the condenser lens 61. The laser light L that has passed through the condenser lens 61 is condensed at a focal position (for example, T1 in FIG. 1) while narrowing.

  When the focal position of the laser beam L is moved away from this state, the grooved outer cylinder 74 is rotated clockwise in FIG. Thus, when the grooved outer cylinder 74 is rotated clockwise, the first lens 62 and the second lens 63 approach the condenser lens 61 while maintaining a predetermined relationship. As described above, when the first lens 62 and the second lens 63 are in a predetermined relationship and approach the condenser lens 61, the laser light L that has passed through the condenser lens 61 has the above-described focal position ( For example, the light is condensed on the back side (for example, T2 in FIG. 1) from T1) in FIG. As a result, the focal position of the laser light L moves away from the back side.

  On the other hand, in order to bring the focal position of the laser beam L closer to the near side from this state, the grooved outer cylinder 74 is rotated counterclockwise in FIG. When the grooved outer cylinder 74 is thus rotated counterclockwise, the first lens 62 and the second lens 63 are moved away from the condenser lens 61 while maintaining a predetermined relationship. As described above, when the first lens 62 and the second lens 63 are moved away from the condenser lens 61 while maintaining a predetermined relationship, the laser light L that has passed through the condenser lens 61 has the above-described focal position ( For example, the light is condensed on the near side (for example, T1 in FIG. 1) with respect to T2) in FIG. Thereby, the focal position of the laser beam L approaches the near side.

  Since the laser cutting device 2 according to the second embodiment of the present invention described above has the focal position changing optical system 6 that can arbitrarily change the focal position of the emitted laser light L, the laser beam L emitted from the head 3 can be changed. The focal position can be changed arbitrarily. Thereby, even when a structure or a building is dismantled using the laser cutting device 2 according to the second embodiment of the present invention, it is not necessary to move the laser cutting device 2 every time steel material or concrete is cut. .

  In the focal position changing optical system according to the second embodiment of the present invention, the second lens can arbitrarily change the focal position of the condenser lens together with the first lens. Thereby, it is not necessary to move the laser cutting device 2 every time steel material or concrete is cut.

  Further, since the laser oscillator 21 according to the second embodiment of the present invention oscillates the multi-mode laser light L, the necessary laser light intensity can be easily obtained. Thereby, the required laser beam intensity can be obtained at an arbitrary position.

  In addition, since the second lens holder 73 according to the second embodiment of the present invention has a flow path through which the coolant flows around the second lens 63, the second lens holder 73 is interposed between the condenser lens 61 and the first lens 62. The provided second lens 63 can be efficiently cooled.

  In the focal position changing optical system 6 according to Embodiment 2 of the present invention described above, the condenser lens 61 and the first lens 62 are each composed of two lenses, and the second lens 63 is a single sheet. Although it is configured with lenses, there is no limitation to this, and it is also possible to increase the number of each lens to have each function.

  In the focus position changing optical system 6, the second lens holder 73 that holds the second lens 63 is provided with a flow path through which a coolant flows to cool the second lens 63. Also, a flow path through which the coolant flows can be provided around the first lens 62, and the condenser lens 61 and the first lens 62 may be cooled.

  Further, the moving module 7 described above is configured by the grooved fixed inner cylinder 71, the first lens holder 72, the second lens holder 73, and the grooved outer cylinder 74, but is not limited to this. Any lens can be used as long as it moves the lens 62 and the second lens 63 with a predetermined relationship.

  In addition, a distance measuring means such as a distance meter for measuring the distance to the cutting objects T1 and T2 is provided, the distance to the cutting objects T1 and T2 is measured, and the focal position of the laser beam L is changed based on the measurement result. It is good to do.

  Further, assist gas injection means for injecting assist gas to the cutting objects T1 and T2 on which the laser beam L is condensed is provided, and when the cutting objects T1 and T2 are cut with the laser beam L, the assist gas is injected and cut. It is good also as what assists.

  As described above, since the focal position of the laser beam can be changed, the present invention is particularly suitable for dismantling structures and structures such as nuclear reactors and bridges that are difficult for humans to approach.

DESCRIPTION OF SYMBOLS 2 Laser cutting device 21 Laser oscillator 22 Control apparatus 23 Optical fiber 3 Head 4 Focus position change optical system 41 Condensing lens 42 1st lens 43 2nd lens 5 Moving module 51 Fixed inner cylinder 511 with a groove | channel 51 Guide holder 52 521 Guide pin 525 Flow path 526 Supply port 527 Discharge port 53 Grooved outer cylinder 531 Actuation groove 6 Focus position changing optical system 61 Condensing lens 62 First lens 63 Second lens 7 Moving module 71 Fixed inner cylinder 711 with groove Guide groove 72 First lens holder 721 Guide pin 73 Second lens holder 731 Guide pin 74 Grooved outer cylinder 741 First operation groove 742 Second operation groove L Laser light T1, T2 Cutting object

Claims (6)

A laser oscillator that oscillates laser light;
An optical fiber through which laser light oscillated from the laser oscillator propagates;
A head for emitting laser light incident from the optical fiber to a cutting object;
A laser cutting device comprising:
The head has a focal position changing optical system capable of arbitrarily changing the focal position of emitted laser light,
The focal position changing optical system is:
A condenser lens that is fixed to the emission side of the head and collects the laser light emitted from the head;
A first lens provided on an incident side of the head and receiving a laser beam emitted from the optical fiber;
A second lens provided between the condenser lens and the first lens so as to be movable along an optical axis direction, and changing a focal position of the condenser lens together with the first lens;
Including
The laser cutting device is
A cylindrical grooved fixed inner cylinder provided with a guide groove extending along the optical axis direction;
A cylindrical lens holder, which is slidably fitted inside the grooved fixed inner cylinder, for holding the second lens, and a guide pin inserted into the guide groove is provided on the lens holder. A lens holder (52) provided on the outer periphery, and a cylindrical grooved outer cylinder into which the grooved fixed inner cylinder is fitted, and a working groove extending in a spiral shape through which the guide pin is inserted. A cylindrical grooved outer cylinder provided,
The laser cutting further comprising: a moving module configured to move the second lens held by the lens holder along the optical axis direction by rotating the grooved outer cylinder. apparatus. A laser oscillator that oscillates laser light;
An optical fiber through which laser light oscillated from the laser oscillator propagates;
A head for emitting laser light incident from the optical fiber to a cutting object;
A laser cutting device comprising:
The head has a focal position changing optical system capable of arbitrarily changing the focal position of emitted laser light,
The focal position changing optical system is:
A condenser lens that is fixed to the emission side of the head and collects the laser light emitted from the head;
A first lens provided on an incident side of the head and receiving a laser beam emitted from the optical fiber;
A second lens provided between the condenser lens and the first lens so as to be movable along an optical axis direction, and changing a focal position of the condenser lens together with the first lens;
Including
The laser cutting device is
A cylindrical grooved fixed inner cylinder provided with a guide groove extending along the optical axis direction;
A cylindrical first lens holder, which is slidably fitted inside the grooved fixed inner cylinder, for holding the first lens, and is inserted into the guide groove. A first lens holder (72) provided with a pin on an outer periphery of the first lens holder;
A cylindrical second lens holder that is slidably fitted to the opposite side of the first lens holder inside the fixed inner cylinder with grooves, and that holds the second lens, A second lens holder (73) in which a second guide pin inserted into the guide groove is provided on the outer periphery of the second lens holder;
A cylindrical grooved outer tube into which the grooved fixed inner tube is fitted inside, a first working groove extending in a spiral shape through which the first guide pin is inserted, and the second guide A cylindrical grooved outer cylinder provided with a second working groove extending spirally through which the pin is inserted,
By rotating the grooved outer cylinder, the first lens held by the first lens holder and the second lens held by the second lens holder are moved in the optical axis direction. A laser cutting apparatus, further comprising: a moving module configured to move along.   The laser cutting apparatus according to claim 1, wherein the first lens is fixed to an incident side of the head.   3. The laser cutting device according to claim 2, wherein the second operation groove is formed in a spiral shape having a gentler gradient than the first operation groove. 4. The laser oscillator is
The laser cutting apparatus according to claim 1, wherein the laser cutting apparatus oscillates a multimode laser beam. A holder (52, 73) for holding the second lens;
The laser cutting device according to any one of claims 1 to 5, wherein the holder has a flow path through which a coolant flows around the second lens.

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