Laser welding machine

Abstract

The utility model discloses a laser welding machine which solves the technical problem that in the prior art, under the condition that specifications of front and back two coils of strip steel are changed, the strip breakage risk is large due to welding of the center position of an abutted seam. The laser welding machine comprises a laser, an upper pipe, a lower pipe assembly, a horizontal pipe, a driving part and a controller, the lower pipe assembly comprises an outer pipe, an inner pipe and a displacement sensor, the outer pipe is coaxially connected with the upper pipe, the inner pipe is coaxially arranged in the outer pipe, the lower end of the inner pipe extends out of the outer pipe, and the inner pipe is used for driving the inner pipe to rotate relative to the outer pipe; the horizontal pipe is connected to the lower end of the inner pipe. Reflecting mirrors are arranged at the two ends of the horizontal pipe. A driving member; and the controller is electrically connected with the displacement sensor and the driving piece. According to the laser welding machine, the position of a laser emitting point is automatically adjusted, the adjusting precision is high, the welding quality is good, and the belt breaking risk is reduced; the method is high in efficiency and suitable for continuous cold rolling production.

Description

Technical Field

[0001] This application belongs to the field of laser welding machine technology, and specifically relates to a laser welding machine. Background Technology

[0002] Laser welding machines are important equipment in pickling and cold rolling production lines. They are used to weld the tail of one coil of strip to the head of the next coil of strip, thereby enabling continuous production on the line.

[0003] For laser welding machines, if the materials and thicknesses of the preceding and following strip steel coils are different, the laser energy required during welding will also differ. Therefore, the optimal laser position is not necessarily the center of the seam between the strip's tail and head, but needs to vary depending on the type of steel in the preceding and following coils. Conversely, for strip steel coils of the same material and thickness, the optimal laser position is the center of the seam between the strip's tail and head. This necessitates an adjustable laser focus position to adapt to production requirements.

[0004] In related technologies, the laser focus adjustment method for laser welding is mechanical and manual. After adjustment, it is necessary to mark the actual position of the focus. If it does not meet the requirements, the adjustment continues. Because this method is inefficient, it cannot be implemented in actual production. In order to balance the specifications of various steel grades, the laser focus can only be adjusted to the center position of the strip seam. This leads to a decrease in welding quality when welding two strips with different specifications, and increases the risk of strip breakage on the production line. Utility Model Content

[0005] To address the technical problem of high risk of strip breakage due to welding at the center of the joint when the specifications of the two strip rolls change, this application provides a laser welding machine.

[0006] In a first aspect of this application, a laser welding machine is provided, comprising:

[0007] A laser, used to emit laser light;

[0008] The upper tube is used to transmit the laser along its own axial direction;

[0009] The lower tube assembly includes an outer tube, an inner tube, a reference strip, and a displacement sensor. The outer tube is coaxially connected to the upper tube. The inner tube is coaxially rotatably disposed inside the outer tube, with its lower end extending out of the outer tube. The reference strip is connected to the outer tube and is perpendicular to the axial direction of the outer tube. The reference strip is at the same height as the lower end of the outer tube. The displacement sensor is disposed outside the lower end of the inner tube, and the tangent at the location of the displacement sensor is perpendicular to the reference strip to detect its own displacement relative to the reference strip.

[0010] A horizontal tube is connected to the lower end of the inner tube. Both ends of the horizontal tube are equipped with reflectors so that the laser is transmitted sequentially in the upper tube, the inner tube and the horizontal tube, and emitted in a direction perpendicular to the horizontal tube for welding.

[0011] A driving component is used to drive the inner tube to rotate relative to the outer tube;

[0012] The controller is electrically connected to the displacement sensor and the drive unit.

[0013] In some embodiments, the lower tube assembly further includes a gear ring located inside the outer tube and coaxially connected to the inner tube. The outer tube has an opening, and the drive member is located outside the outer tube and has a gear shaft that extends into the outer tube through the opening and meshes with the gear ring.

[0014] In some embodiments, the lower tube assembly further includes a housing, the outer tube is connected to the upper tube through the housing, the housing has the opening, the gear ring is located inside the housing, the upper end of the inner tube extends from the outer tube into the housing, the upper end of the inner tube is rotatably connected to the housing through a first bearing, and the lower end of the inner tube is rotatably connected to the outer tube through a second bearing.

[0015] In some embodiments, the gear ring is connected to the upper end face of the inner tube, the gear ring extends radially out of the inner tube, and the portion of the gear ring extending radially out of the inner tube abuts against the inner ring of the first bearing.

[0016] In some embodiments, a support ring located within the housing is also included, with both ends of the support ring acting axially on the outer ring of the first bearing and the upper end face of the outer tube.

[0017] In some embodiments, the upper end of the outer tube extends radially, and the radially extended portion of the upper end of the outer tube is fitted to the support ring and connected to the housing by fasteners.

[0018] In some embodiments, the lower end of the outer tube is provided with a notch to avoid the second bearing shaft, and the inner tube is provided with a stepped surface for axially limiting the second bearing, the stepped surface facing upward and abutting against the inner ring of the second bearing.

[0019] In some embodiments, the lower end of the outer tube extends radially, and the radially extended portion of the lower end of the outer tube is connected to the reference strip, and the radially extended portion of the lower end of the outer tube corresponds to the position of the notch.

[0020] In some embodiments, the lower tube assembly further includes a limiting bearing for axially limiting the gear ring, the limiting bearing being located within the housing, the seat ring and shaft ring of the limiting bearing acting on the inner wall of the housing and the end face of the gear ring, respectively.

[0021] In some embodiments, the housing is provided with a limiting protrusion located inside the housing, the upper ring of the limiting bearing is sleeved outside the limiting protrusion, and the limiting protrusion is provided with a through hole for the laser to pass through and coaxially communicate with the inner tube.

[0022] In some embodiments, the outer tube is connected to the housing via a threaded connection.

[0023] A laser welding machine according to an embodiment of this application includes a laser, an upper tube, a lower tube assembly, a horizontal tube, a drive unit, and a controller. The laser is used to emit laser light; the upper tube is used to transmit the laser light along its own axial direction; the lower tube assembly includes an outer tube, an inner tube, and a displacement sensor. The outer tube is coaxially connected to the upper tube, and the inner tube is coaxially rotatably disposed inside the outer tube with its lower end extending out of the outer tube. A reference strip is connected to the outer tube and is perpendicular to the axial direction of the outer tube. The reference strip is at the same height as the lower end of the outer tube. The displacement sensor is disposed outside the lower end of the inner tube, and the tangent at the location of the displacement sensor is perpendicular to the reference strip to detect the distance between itself and the reference strip; the horizontal tube is connected to the lower end of the inner tube, and both ends of the horizontal tube are provided with reflectors so that the laser light is transmitted sequentially in the upper tube, the inner tube, and the horizontal tube, and emitted in a direction perpendicular to the horizontal tube for welding; the drive unit is used to drive the inner tube to rotate relative to the outer tube; the controller is electrically connected to the displacement sensor and the drive unit.

[0024] The laser emitted by the laser travels axially along the upper tube, inner tube, and horizontal tube, and then exits perpendicularly to the horizontal tube at the seam between the two strip rolls. Since the drive unit can rotate the inner tube relative to the outer tube, and the horizontal tube is connected to the lower end of the inner tube, the rotation of the inner tube around its central axis causes the end of the horizontal tube furthest from the inner tube to move in a circular motion around the inner tube, thus adjusting the position of the laser emitted axially perpendicular to the horizontal tube. When welding two strip rolls of different materials and thicknesses, the laser emission position needs to be adjusted from the center of the seam to the target position. Since the length of the horizontal tube and the distance between the seam center and the target position can be obtained, the target position of the horizontal tube (which is also the inner tube) can be determined. The displacement sensor can detect its own displacement relative to the reference strip. Therefore, when the controller detects that the displacement between the displacement sensor and the reference strip reaches the target displacement, it controls the drive unit to stop, at which point the laser can be emitted to the target position.

[0025] This application uses a displacement sensor to determine its own displacement relative to the reference strip, thereby determining the relative rotation angle between the inner and outer tubes. When the displacement of the displacement sensor is equal to the target displacement, the drive component stops moving, realizing automatic adjustment of the laser emission point position. The adjustment accuracy is high, the welding quality is good, and the risk of strip breakage is reduced. It is also highly efficient and suitable for continuous cold rolling production. Attached Figure Description

[0026] Figure 1 A schematic diagram of the overall structure of a laser welding machine in one or more embodiments of this application is shown.

[0027] Figure 2 It shows Figure 1 A magnified view of a portion of the image.

[0028] Figure 3 A schematic diagram showing the position of the displacement sensor and the reference bar in a laser welding machine is shown.

[0029] Figure 4 A schematic diagram showing the relative positions of the outer tube, displacement sensor, and reference bar is provided.

[0030] Figure 5 A schematic diagram of the lower tube assembly is shown.

[0031] Explanation of reference numerals in the attached figures:

[0032] 10-Laser, 20-Connecting tube, 30-Upper tube, 40-Lower tube assembly, 401-Housing, 4011-Limiting protrusion, 402-Limiting bearing, 403-Gear ring, 404-First bearing, 405-Support ring, 406-Inner tube, 4061-Step surface, 407-Outer tube, 4071-Notch, 408-Second bearing, 409-Reference bar, 410-Driver, 4101-Gear shaft, 411-Displacement sensor, 50-Horizontal tube, 60-Reflector. Detailed Implementation

[0033] To enable those skilled in the art to more clearly understand this application, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0034] According to the first aspect of this application, a laser welding machine is provided that can automatically adjust the position of the laser focus, resulting in high production efficiency, high adjustment accuracy, high welding quality, and reduced risk of laser band breakage.

[0035] Please see Figure 1 as well as Figure 2 The present application provides a laser welding machine, which includes a laser 10, an upper tube 30, a lower tube assembly 40, a horizontal tube 50, a drive unit 410, and a controller.

[0036] Laser 10 is a device capable of generating laser light. It achieves laser light generation through specific working substances, excitation sources, optical resonant cavities, and other components; it is used to emit laser light.

[0037] The upper tube 30 is used to transmit the laser emitted by the laser 10 along its own axis and is set vertically;

[0038] Please see Figure 2 The lower tube assembly 40 is connected to the upper tube 30, allowing the laser transmitted from the upper tube 30 to continue to be transmitted along the axial direction of the lower tube assembly 40. The lower tube assembly 40 includes an outer tube 407, an inner tube 406, and a displacement sensor 411. The outer tube 407 is coaxially connected to the upper tube 30 to fix the outer tube 407. The inner tube 406 is coaxially and rotatably disposed inside the outer tube 407, so that the inner tube 406 does not interfere with the outer tube 407 when it rotates. The lower end of the inner tube 406 extends out of the outer tube 407 to facilitate connection with the horizontal tube 50. Please refer to [link to relevant documentation]. Figure 2 , Figure 3 as well as Figure 5A reference strip 409 is connected to the outer tube 407 and is perpendicular to the axis of the outer tube 407. The lower end of the reference strip 409 is at the same height as the lower end of the outer tube 407. A displacement sensor 411 is located on the outer side of the lower end of the inner tube. The tangent at the location of the displacement sensor 411 is perpendicular to the length direction of the reference strip 409, so that the displacement sensor 411 can detect its own displacement relative to the reference strip 409. During the rotation of the inner tube 406, the displacement sensor 411 detects the distance it moves relative to the reference strip 409. When the distance between the displacement sensor 411 and the reference strip 409 changes, that is, when the displacement reaches the target displacement, the laser emitted by the horizontal tube 50 reaches the target position. In production, the position adjustment interval of the laser welding point is approximately ±0.2mm, which is very small. The relative rotation angle between the outer tube 407 and the inner tube 406 is approximately 0.2°~0.3°, which is also very small. If an angle sensor is used to detect the relative rotation angle between the outer tube 407 and the inner tube 406, the error will be relatively large, which will not meet the adjustment requirements of the laser welding point. Because the relative rotation angle between the outer tube 407 and the inner tube 406 is very small, the radial change of the displacement sensor 411 located on the outer side of the inner tube 406 during position changes is almost negligible. The positional change along the tangential direction (approximately ±0.05mm) can be used to determine the start and stop timing of the drive component 410, improving the position adjustment accuracy of the laser welding point. The displacement sensor 411 can be a sensor that directly measures the distance change of the displacement sensor 411 relative to the reference strip 409, i.e., the displacement. It is recommended to use a high-precision sensor for the displacement sensor 411, such as a grating ruler displacement sensor with a detection accuracy in the μm range, to ensure the adjustment requirements are met.

[0039] Please see Figure 1 The horizontal tube 50 is set horizontally and connected to the lower end of the inner tube 406. Both ends of the horizontal tube 50 are equipped with reflectors 60 so that the laser is transmitted sequentially in the upper tube 30, the inner tube 406 and the horizontal tube 50, and emitted in a direction perpendicular to the horizontal tube 50 for welding.

[0040] The drive unit 410 can be a servo motor, which can drive the inner tube 406 to rotate relative to the outer tube 407.

[0041] The controller is electrically connected to the displacement sensor and the drive unit 410 to acquire the displacement of the displacement sensor 411, compare the displacement change value with the target displacement, and control the drive unit 410 to stop operation when the displacement of the displacement sensor 411 equals the target displacement. The controller can be the controller of the pickling and cold rolling production line, or it can be a separately installed controller. If the controller is a separately installed controller, it can be electrically connected to the controller of the pickling and cold rolling production line to achieve interlocking control.

[0042] In some embodiments, please refer to Figure 2The lower tube assembly 40 also includes a gear ring 403, which is located inside the outer tube 407 and coaxially connected to the inner tube 406, so that the gear ring 403 drives the inner tube 406 to rotate. The outer tube 407 has an opening, and the driving member 410 is installed outside the outer tube 407 and has a gear shaft 4101. The gear shaft 4101 extends into the outer tube 407 through the opening and meshes with the gear ring 403, so as to drive the gear ring 403 and the inner tube 406 to rotate, so that the horizontal tube 50 rotates around the inner tube 406. In some other embodiments, the driving member 410 may also be arranged inside the outer tube 407, which can also realize the relative rotation between the outer tube 407 and the inner tube 406.

[0043] In some embodiments, please combine Figure 2 The lower tube assembly 40 also includes a housing 401. The outer tube 407 is connected to the upper tube 30 through the housing 401. The housing 401 has an opening, and a gear ring 403 is located inside the housing 401. The upper end of the inner tube 406 extends from the outer tube 407 into the housing 401. This split structure design of the housing 401 and the outer tube 407 facilitates the installation of the inner tube 406 and the gear ring 403. In other embodiments, the housing 401 and the outer tube 407 can also be an integral structure, which also allows the inner tube 406 to be installed with the gear ring 403.

[0044] In some embodiments, please combine Figure 2 The upper end of the inner tube 406 is rotatably connected to the housing 401 via a first bearing 404, and the lower end of the inner tube 406 is rotatably connected to the outer tube 407 via a second bearing 408. The inner tube 406's rotatable connection to the external structure via two bearings provides greater stability. In other embodiments, the inner tube 406 can also be slidably connected to the housing 401 and the outer tube 407, still allowing for relative rotation between the inner tube 406 and the outer tube 407, thereby adjusting the position of the laser emission point.

[0045] In some embodiments, please combine Figure 2 The gear ring 403 is connected to the upper end face of the inner tube 406. Specifically, the gear ring 403 can be connected to the upper end face of the inner tube 406 via a threaded connection. The gear ring 403 extends radially out of the inner tube 406, and the portion of the gear ring 403 extending radially out of the inner tube 406 abuts against the inner ring of the first bearing 404. Therefore, the gear ring 403 achieves both power transmission and axial upper limit positioning of the first bearing 404. In other embodiments, the gear ring 403 is sleeved on the outside of the inner tube 406 and abuts against the inner ring of the first bearing 404, which also achieves power transmission and axial upper limit positioning of the first bearing 404. In yet another embodiment, the outer surface of the inner tube 406 is provided with a limiting protrusion 4011 that abuts against the inner ring of the first bearing 404, which also achieves axial upper limit positioning of the first bearing 404.

[0046] In some embodiments, please combine Figure 2The lower tube assembly 40 also includes a support ring 405 located within the housing 401. The two axial ends of the support ring 405 act on the outer ring of the first bearing 404 and the upper end face of the outer tube 407 to achieve axial lower limiting of the first bearing 404 and save space. In other embodiments, the outer ring of the first bearing 404 can also directly abut against the upper end face of the outer tube 407 to achieve axial lower limiting of the first bearing 404. In yet another embodiment, the housing 401 is provided with a limiting protrusion 4011 that abuts against the outer ring of the first bearing 404, which can also achieve axial lower limiting in the first axial direction.

[0047] In some embodiments, the upper end of the outer tube 407 extends radially, and the radially extended portion of the upper end of the outer tube 407 is fitted against the support ring 405 and connected to the housing 401 by fasteners. The outer tube 407's shape, wider at the top and narrower at the bottom, saves space and allows for a rotatable connection with the inner tube 406 and a connection with the housing 401. In other embodiments, the wall thickness of the outer tube 407 remains constant along its own axial direction, and the upper end face of the outer tube 407 abuts against the support ring 405 and is connected to the housing 401, which also allows for a rotatable connection between the inner tube 406 and the outer tube 407 and a connection with the housing 401.

[0048] In some embodiments, please combine Figure 2 The lower end of the outer tube 407 is provided with a notch 4071 to avoid the second bearing 408, and the inner tube 406 is provided with a stepped surface 4061 for axially limiting the second bearing 408. The stepped surface 4061 faces upward and abuts against the inner ring of the second bearing 408.

[0049] In some embodiments, please combine Figure 2 The lower end of the outer tube 407 extends radially, and the radially extended portion of the lower end of the outer tube 407 is connected to the reference strip 409. The radially extended portion of the lower end of the outer tube 407 corresponds to the position of the notch 4071, so that the lower end of the outer tube 407 can avoid the second bearing 408 without reducing the strength at this point.

[0050] In some embodiments, please combine Figure 2 The lower tube assembly 40 also includes a limiting bearing 402 for axially limiting the gear ring 403. The limiting bearing 402 is located inside the housing 401. The seat ring and shaft ring of the limiting bearing 402 act on the inner wall of the housing 401 and the end face of the gear ring 403, respectively, to axially limit the inner tube 406 and improve the connection stability between the inner tube 406 and the housing 401. The limiting bearing 402 can be a thrust ball bearing.

[0051] In some embodiments, the housing 401 is provided with a limiting protrusion 4011, which is located inside the housing 401. The upper ring of the limiting bearing 402 is sleeved outside the limiting protrusion 4011 to radially limit the limiting bearing 402 and improve the connection stability between the limiting bearing 402 and the housing 401. The limiting protrusion 4011 is provided with a through hole for the laser to pass through and coaxially communicate with the inner tube 406 to enable laser transmission.

[0052] In some embodiments, the outer tube 407 is connected to the housing 401 by threaded fasteners, and multiple threaded fasteners may be provided, with multiple threaded fasteners wound around the outer tube 406. In some embodiments, the inner tube 406 and the horizontal tube 50 may also be connected by threaded fasteners, facilitating the installation and maintenance of the reflector 60 inside.

[0053] In some embodiments, please combine Figure 2 The laser welding machine also includes a connecting pipe 20. The laser 10 is connected to the upper pipe 30 through the connecting pipe 20. The connecting pipe 20 and the upper pipe 30 are perpendicular to each other. A reflector 60 is provided at the connection between the connecting pipe 20 and the upper pipe 30 so that the laser emitted by the laser 10 is first transmitted through the horizontal connecting pipe 20, then transmitted vertically downward along the upper pipe 30 and the inner pipe 406, then transmitted horizontally along the horizontal pipe 50, and finally emitted to the target position in a direction perpendicular to the horizontal pipe 50.

[0054] The adjustment process of the laser 10 provided in this application is as follows:

[0055] When the material and specifications of two adjacent strip steel rolls change, the target position and target displacement are first determined. Then, the drive component 410 is activated, and the gear shaft 4101 drives the gear ring 403 to rotate, thereby causing the inner tube 406 to rotate around its own central axis. This causes the end of the horizontal tube 50 away from the inner tube 406 to make a circular motion around the inner tube 406 as the center, thereby adjusting the position of the laser emitted from the axis perpendicular to the horizontal tube 50. When the inner tube 406 rotates to the point where the displacement detected by the displacement sensor 411 is equal to the target displacement, the controller controls the drive component 410 to stop, and the adjustment ends.

[0056] The laser welding machine provided in this application can automatically adjust the position of the laser focus using a controller, which has the advantages of high adjustment accuracy, good welding quality, reduced risk of strip breakage, simple operation, high production efficiency, and strong safety factor.

[0057] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0058] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0059] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0060] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0061] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A laser welder characterized by, include: A laser, used to emit laser light; The upper tube is used to transmit the laser along its own axial direction; The lower tube assembly includes an outer tube, an inner tube, a reference strip, and a displacement sensor. The outer tube is coaxially connected to the upper tube. The inner tube is coaxially rotatably disposed inside the outer tube, with its lower end extending out of the outer tube. The reference strip is connected to the outer tube and is perpendicular to the axial direction of the outer tube. The reference strip is at the same height as the lower end of the outer tube. The displacement sensor is disposed outside the lower end of the inner tube, and the tangent at the location of the displacement sensor is perpendicular to the reference strip to detect its own displacement relative to the reference strip. A horizontal tube is connected to the lower end of the inner tube. Both ends of the horizontal tube are equipped with reflectors so that the laser is transmitted sequentially in the upper tube, the inner tube and the horizontal tube, and emitted in a direction perpendicular to the horizontal tube for welding. A driving component is used to drive the inner tube to rotate relative to the outer tube; The controller is electrically connected to the displacement sensor and the drive unit.

2. The laser welder of claim 1, wherein, The lower tube assembly also includes a gear ring located inside the outer tube and coaxially connected to the inner tube. The outer tube has an opening, and the drive unit is located outside the outer tube and has a gear shaft. The gear shaft extends into the outer tube through the opening and meshes with the gear ring.

3. The laser welder of claim 2, wherein, The lower tube assembly also includes a housing, an outer tube connected to the upper tube through the housing, the housing having a through hole communicating with the upper tube and the opening, the gear ring located inside the housing, the upper end of the inner tube extending from the outer tube into the housing, the upper end of the inner tube being rotatably connected to the housing through a first bearing, and the lower end of the inner tube being rotatably connected to the outer tube through a second bearing.

4. The laser welder of claim 3, wherein, The gear ring is connected to the upper end face of the inner tube, the gear ring extends radially out of the inner tube, and the portion of the gear ring extending radially out of the inner tube abuts against the inner ring of the first bearing.

5. The laser welder of claim 3, wherein, It also includes a support ring located inside the housing, the two ends of which act on the outer ring of the first bearing and the upper end face of the outer tube.

6. The laser welder of claim 5, wherein, The upper end of the outer tube extends radially, and the radially extended portion of the upper end of the outer tube is attached to the support ring and connected to the housing by fasteners.

7. The laser welder of claim 3, wherein, The lower end of the outer tube is provided with a notch to avoid the second bearing, and the inner tube is provided with a stepped surface for axially limiting the second bearing. The stepped surface faces upward and abuts against the inner ring of the second bearing.

8. The laser welder of claim 7, wherein, The lower end of the outer tube extends radially, and the radially extended portion of the lower end of the outer tube is connected to the reference strip. The radially extended portion of the lower end of the outer tube corresponds to the position of the notch.

9. Laser beam welding machine according to any one of claims 3 to 8, characterized in that The lower tube assembly also includes a limiting bearing for axially limiting the gear ring. The limiting bearing is located inside the housing, and the seat ring and shaft ring of the limiting bearing act on the inner wall of the housing and the end face of the gear ring, respectively.

10. The laser welder of claim 9, wherein, The housing is provided with a limiting protrusion located inside the housing. The upper ring of the limiting bearing is sleeved outside the limiting protrusion. The limiting protrusion is provided with a through hole for the laser to pass through and coaxially connected with the inner tube.

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