Semitrailer bottom plate laser welding equipment and welding method

Abstract

The invention provides semitrailer bottom plate laser welding equipment and welding method.The semitrailer bottom plate laser welding equipment comprises an operation table and a portal frame, the portal frame slides on the operation table, and a supporting plate used for supporting a frame is arranged on the operation table; the welding unit comprises a first-stage sliding seat, a second-stage sliding seat and a third-stage sliding seat, the first-stage sliding seat slides on the portal frame, the first-stage sliding seat is rotatably connected with the second-stage sliding seat, a welding mechanical arm is arranged on the third-stage sliding seat, and the welding mechanical arm slides on the second-stage sliding seat under the traction of the third-stage sliding seat; and the abutting assembly is arranged on the second-stage sliding seat. The welding quality is guaranteed through linear movement of the three-stage sliding seat, direct movement of the welding mechanical arm is reduced, and the abutting assembly is adjusted along with the three-stage sliding seat, so that the position nearby a welding area is in a flat state.

Description

Technical Field

[0001] The invention belongs to the technical field of laser welding equipment, and in particular relates to a semitrailer bottom plate laser welding equipment and a welding method. Background Art

[0002] The bottom plate of a semi-trailer is usually laid out on the frame by paving, and then the bottom plate and the frame are welded together. Since the bottom plate itself will be cut into rectangles of appropriate size for welding as needed, the welding is usually done directly on the frame to avoid forming an overall structure after the bottom plate is welded, which makes it difficult to lay it on the frame.

[0003] During the welding process of the semi-trailer floor, the operating surface is located on the frame, and the frame itself is large in size. Currently, most automated welding equipment uses simple multi-axis robotic arms for welding. When welding operations are performed on a large operating surface, cumulative errors will occur during movement and adjustment due to the large operating range, resulting in poor welding effects. The floor uses a large-area steel plate structure, which is prone to warping after laying. Direct welding by automated welding equipment will further affect welding due to deformation. Summary of the invention

[0004] The present invention provides a semi-trailer bottom plate laser welding device, aiming to solve the problem that the current automated welding equipment has a simple structure and an insufficient welding effect for bottom plate structures with large operating surfaces.

[0005] The present invention is implemented as follows: a semi-trailer bottom plate laser welding device, comprising:

[0006] An operating table and a gantry, wherein the gantry slides on the operating table, and a supporting plate for supporting a vehicle frame is provided on the operating table;

[0007] A welding unit, the welding unit comprising a primary sliding seat, a secondary sliding seat and a tertiary sliding seat, the primary sliding seat slides on the gantry, the primary sliding seat is rotatably connected to the secondary sliding seat, a welding mechanical arm is provided on the tertiary sliding seat, and the welding mechanical arm slides on the secondary sliding seat under the traction of the tertiary sliding seat;

[0008] The supporting component is arranged on the secondary sliding seat, and the supporting component provides a supporting force to the bottom plate placed on the frame to maintain the flatness between the bottom plates during the welding process of the welding robot arm.

[0009] Preferably, the secondary sliding seat comprises a main bearing plate, a base and a rotating mechanism, wherein the base is arranged in the middle section of the main bearing plate, one end of the rotating mechanism is connected to the base, and the other end is connected to the end surface of the primary sliding seat away from the gantry;

[0010] When the third-level sliding seat needs to change the processing direction of the welding robot arm, the rotating mechanism changes the relative angle between the second-level sliding seat and the first-level sliding seat.

[0011] Preferably, the number of the abutting components is several groups, and the abutting components include a base fixed on the secondary sliding seat, a base rod and a telescopic rod arranged at the end of the base rod; the end of the telescopic rod abuts around the part to be welded;

[0012] The base is provided with a measuring instrument. When different measuring instruments obtain different distance data, the corresponding supporting assembly applies pressure to the bottom plate through the telescopic rod to ensure that the bottom plate is in a relatively flat state.

[0013] Preferably, the gantry comprises a main beam and a sliding frame, the main beam is provided with a screw transmission unit, the primary sliding seat is connected to the screw transmission unit, the screw transmission unit drives the welding unit to move laterally along the frame, and the sliding frame moves longitudinally along the frame.

[0014] Preferably, the three-stage sliding seat is provided with a linear motor slider and a guide slider;

[0015] The main bearing plate is provided with a linear motor on the end face away from the primary sliding seat, and the linear motor slider slides in the track groove provided on the linear motor. The main bearing plate is also provided with a guide groove on the end face away from the primary sliding seat, and the guide slider slides in the guide groove.

[0016] Preferably, a screw guide groove and a sliding guide rail are provided on the main beam, and a screw for driving the primary sliding seat to move is provided in the screw guide groove;

[0017] The end surface of the primary sliding seat away from the secondary sliding seat is provided with a movable slider and a directional guide groove, and the primary sliding seat slides on the sliding guide rail through the directional guide groove; the movable slider extends into the lead screw guide groove and is assembled on the lead screw.

[0018] Preferably, the operating table comprises a first side frame and a second side frame, and the first side frame and the second side frame are connected by a first connecting beam and a second connecting beam;

[0019] There are two groups of support plates, which are respectively arranged on the first side frame and the second side frame. The support plates support the vehicle frame located between the first side frame and the second side frame.

[0020] Preferably, the number of the sliding frames is two groups, and the ends of different sliding frames slide on the tops of the first side frame and the second side frame respectively, and guide rails are provided.

[0021] Preferably, a welding method of the semi-trailer floor laser welding equipment as described above comprises the following steps:

[0022] Step 1: The frame is hoisted between the first side frame and the second side frame by an external hoisting device. After the hoisting is completed, the frame is pushed until the end of the frame is against the stop bar provided on the second connecting beam;

[0023] Step 2: Use the winch equipment on the gantry to hoist and lay the bottom plate above the frame, and then cover the frame after the bottom plate is leveled;

[0024] Step 3: Retract the winch equipment, start the welding unit, and let the welding robot arm reach the top of the weld to be welded through the cooperation of the first-level sliding seat, the second-level sliding seat and the third-level sliding seat, so that the sliding direction of the third-level sliding seat is parallel to the direction of the weld;

[0025] Step 4: Before welding, adjust the supporting assembly to support the bottom plate, and adjust the length of the telescopic rod in the supporting assembly according to the data fed back by the measuring instrument to keep the adjacent bottom plates relatively flat;

[0026] Step 5: When performing longitudinal welding, the secondary sliding seat rotates and the tertiary sliding seat moves longitudinally for welding. When performing transverse welding, the secondary sliding seat rotates and the tertiary sliding seat moves transversely for welding.

[0027] Preferably, a winch platform is also provided on the main beam, the winch equipment is arranged on the winch platform, and the winch platform is connected to the primary sliding seat.

[0028] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0029] 1. The semi-trailer bottom plate laser welding equipment provided by the present invention uses a primary sliding seat and a secondary sliding seat as a three-stage sliding seat adjustment component, utilizes the movement of the three-stage sliding seat to pull the welding robot arm to move during the welding process, and uses the linear movement of the three-stage sliding seat to ensure the welding quality and reduce the direct movement of the welding robot arm to affect the welding effect.

[0030] 2. The semi-trailer bottom plate laser welding equipment provided by the present invention provides a supporting force to the bottom plate placed on the frame during the welding process of the welding robot arm to maintain the flatness between the bottom plates. The supporting component will actively push the bottom plate to deform so as to keep it flat. The supporting component is synchronously adjusted with the movement direction of the three-stage sliding seat to keep the area near the welding area in a relatively flat state, thereby improving the welding effect during the welding process. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The present invention is a schematic structural diagram of a semi-trailer bottom plate laser welding device provided by the present invention.

[0032] Figure 2The present invention is a schematic diagram of the structure of an operating table of a semitrailer bottom plate laser welding device provided by the present invention.

[0033] Figure 3 The present invention provides a schematic structural diagram of a gantry welding unit of a semitrailer bottom plate laser welding device.

[0034] Figure 4 The present invention is a schematic structural diagram of a welding unit in a semitrailer bottom plate laser welding device.

[0035] Figure 5 The present invention provides a three-sliding seat structure schematic diagram of a semitrailer bottom plate laser welding device.

[0036] Figure 6 The present invention provides a schematic diagram of the secondary sliding seat structure of a semitrailer bottom plate laser welding device.

[0037] Figure 7 The present invention provides a schematic structural diagram of a winch platform and a first-level sliding seat of a semitrailer bottom plate laser welding device.

[0038] Figure 8 The present invention provides a schematic diagram of the structure of a supporting component of a semitrailer bottom plate laser welding device.

[0039] Fig. 9 The present invention is a schematic diagram of the structure of a measuring instrument for a semitrailer bottom plate laser welding device.

[0040] Fig.10 The present invention provides a schematic diagram of the bottom structure of a main bearing plate of a semi-trailer bottom plate laser welding device.

[0041] Fig.11 The present invention provides a schematic diagram of the main beam bottom structure of a semitrailer bottom plate laser welding device.

[0042] Description of reference numerals:

[0043] 100, operating table; 110, first side frame; 120, second side frame; 130, supporting plate; 141, first connecting beam; 142, second connecting beam; 150, stop bar;

[0044] 200, gantry; 210, main beam; 211, lead screw guide groove; 212, sliding guide rail; 213, first guide groove; 214, second guide groove; 220, sliding frame; 221, supporting beam; 222, supporting frame;

[0045] 300, welding unit; 310, primary sliding seat; 320, secondary sliding seat; 321, main bearing plate; 322, base; 323, rotating mechanism; 324, wing plate; 325, guide slide; 330, linear motor; 340, tertiary sliding seat; 341, linear motor slider; 342, guide slider; 350, welding robot arm; 360, holding assembly; 361, base; 362, telescopic rod; 363, base rod; 364, measuring instrument; 370, winch platform;

[0046] 400. Frame. DETAILED DESCRIPTION

[0047] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of this application; the terms used in the specification of the application herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, not to describe a specific order.

[0048] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0049] The embodiment of the present invention provides a semi-trailer bottom plate laser welding device, such as Figure 1-Figure 11 As shown, the semi-trailer bottom plate laser welding equipment comprises:

[0050] An operating table 100, a gantry 200 and a welding unit 300;

[0051] The operating table 100 includes a first side frame 110 and a second side frame 120, and the first side frame 110 and the second side frame 120 are connected by a first connecting beam 141 and a second connecting beam 142; the frame 400 is placed between the first side frame 110 and the second side frame 120 before processing, and the first side frame 110 and the second side frame 120 are provided with a supporting plate 130 for supporting the frame 400; the supporting plate 130 can be designed into a strip structure or a stepped structure according to the shape of the semi-trailer frame, and the supporting plate 130 is provided with a support plate 130 for supporting the frame 400.

[0052] The gantry 200 includes a main beam 210 and a sliding frame 220. The main beam 210 is provided with a screw transmission unit. The sliding frame 220 moves longitudinally along the frame 400.

[0053] The welding unit 300 includes a primary sliding seat 310, a secondary sliding seat 320, a tertiary sliding seat 340, and a supporting assembly 360 disposed on the secondary sliding seat 320. The primary sliding seat 310 slides on the gantry 200. The primary sliding seat 310 is rotatably connected to the secondary sliding seat 320. A welding robot arm 350 is disposed on the tertiary sliding seat 340. The tertiary sliding seat 340 slides on the secondary sliding seat 320 through a linear motor technology.

[0054] The primary sliding seat 310 is connected to the screw transmission unit, and the screw transmission unit drives the welding unit 300 to move laterally along the frame 400, and the sliding frame 220 moves longitudinally along the frame 400 to realize the regional movement of the primary sliding seat 310;

[0055] The number of the abutting components 360 is several groups, and the abutting components 360 include a base 361 fixed on the secondary sliding seat 320, a base rod 363 and a telescopic rod 362 arranged at the end of the base rod 363; the end of the telescopic rod 362 is abutted around the part to be welded; a measuring instrument 364 is provided on the base 361, and when different measuring instruments 364 obtain different distance data, the corresponding abutting components 360 apply pressure to the bottom plate through the telescopic rod 362 to ensure that the bottom plate is in a relatively flat state.

[0056] In the present application, when performing longitudinal welding, the secondary sliding seat 320 is rotated so that the secondary sliding seat 320 and the main beam 210 are in a vertical state, and the tertiary sliding seat 340 is moved in the longitudinal direction for welding. When performing transverse welding, the secondary sliding seat 320 is rotated so that the secondary sliding seat 320 and the main beam 210 are in a parallel state, and the tertiary sliding seat 340 is moved in the transverse direction for welding; the welding mechanical arm 350 is moved during the welding process by the movement of the tertiary sliding seat 340. Here, the welding mechanical arm 350 is a multi-axis laser welding mechanical arm in the prior art, and can be adjusted in angle and position in a small range as needed. Generally speaking, during the welding process, the welding mechanical arm 350 remains stationary and is moved by the movement of the tertiary sliding seat 340. The bottom of the semi-trailer is a linear welding, and the linear movement of the tertiary sliding seat 340 can be used to ensure the welding quality and reduce the direct movement of the welding mechanical arm 350 to affect the welding effect;

[0057] The abutting assembly 360 provides abutting force to the bottom plate placed on the vehicle frame 400 to maintain the flatness between the bottom plates during the welding process of the welding robot arm 350, and the measuring instrument 364 analyzes based on the distance data. When adjacent abutting assemblies 360 obtain different distance data, it indicates that the bottom plate is not flat enough and warps. In this way, the adjacent abutting assemblies 360 will obtain different distance data. At this time, the abutting assembly 360 will actively push the bottom plate to deform so as to keep the bottom plate flat. The abutting assembly 360 is arranged along the movement direction of the three-stage sliding seat 340, so that the area near the welding area can be in a relatively flat state.

[0058] As a preferred implementation in this embodiment, the secondary sliding seat 320 includes a main bearing plate 321, a base 322 and a rotating mechanism 323, wherein the base 322 is arranged in the middle section of the main bearing plate 321, and one end of the rotating mechanism 323 is connected to the base 322, and the other end is connected to the end surface of the primary sliding seat 310 away from the gantry 200; the rotating mechanism 323 adopts the existing rotating motor technology, mainly changes the relative angle between the secondary sliding seat 320 and the primary sliding seat 310, and when the tertiary sliding seat 340 needs to change the processing direction of the welding robot arm 350, the tertiary sliding seat 340 is switched between longitudinal movement and lateral movement;

[0059] In this embodiment, a wing plate 324 is further provided between the main bearing plate 321 and the base 322 for structural reinforcement. Here, the secondary sliding seat 320 serves as a motion guide component of the tertiary sliding seat 340, and the rotating mechanism 323 is used to change the moving direction of the tertiary sliding seat 340, thereby realizing the needs of longitudinal welding and transverse welding during the welding process;

[0060] As a preferred implementation in this embodiment, the end surface of the main bearing plate 321 away from the primary sliding seat 310 is provided with a linear motor 330, and the end surface of the main bearing plate 321 away from the primary sliding seat 310 is also provided with a guide slide groove 325, and the tertiary sliding seat 340 is provided with a linear motor slider 341 and a guide slider 342; the linear motor slider 341 slides in the track groove provided on the linear motor 330, and the guide slider 342 slides in the guide slide groove 325;

[0061] In this embodiment, the linear motor slider 341 and the linear motor 330 adopt the existing technical means, and the movement needs of the three-stage sliding seat 340 are mainly achieved by the above method; the three-stage sliding seat 340 and the welding robot arm 350 can be regarded as a whole, and the linear movement of the three-stage sliding seat 340 is equivalent to the linear movement of the welding robot arm 350. Here, the movement direction of the three-stage sliding seat 340 is usually adjusted to a state parallel to the welding line, and the welding robot arm 350 performs welding processing on the welding line;

[0062] In a further preferred embodiment of the present invention, a screw guide groove 211 and a sliding guide rail 212 are provided on the main beam 210, and a movable slider and a directional guide groove are provided on the end surface of the primary sliding seat 310 away from the secondary sliding seat 320, and the primary sliding seat 310 slides on the sliding guide rail 212 through the directional guide groove; the movable slider extends into the screw guide groove 211 and is assembled on the screw, and a screw transmission unit is provided on the main beam 210 using the existing technology, and the movable slider is a ball slider in the existing screw transmission; the screw is used as a transmission component between the main beam 210 and the primary sliding seat 310;

[0063] The sliding frame 220 includes a supporting beam 221 and a supporting frame 222 respectively arranged at both ends of the main beam. The supporting frames 222 are spaced apart. The spacing design allows the secondary sliding seat 320 to be inserted between the supporting frames 222 during the adjustment process, thereby reducing the processing dead angle. The bottom plate of the supporting frame 222 is moved by a traction trolley and slides on the top of the first side frame 110 and the second side frame 120, and a guide rail is provided;

[0064] In this embodiment, the traction trolley and the guide rail are both based on the existing technology, and the specific structure is the same as the principle of the longitudinal movement of the existing gantry crane. This application does not elaborate on the technology of the gantry crane movement;

[0065] As a preferred implementation in this embodiment, a winch platform 370 is further provided on the main beam 210, and the winch equipment is arranged on the winch platform 370, and the winch platform 370 is connected to the primary sliding seat 310; a first guide groove 213 and a second guide groove 214 are provided on the main beam 210, and the winch platform 370 is an inverted L-shaped structure, and a sliding limit block adapted to the first guide groove 213 and the second guide groove 214 is provided on the winch platform 370, and when the primary sliding seat 310 moves, the winch platform 370 can also be pulled to move laterally along the frame 400;

[0066] In this embodiment, the hoisting platform 370 is provided with a hoisting device, and the hoisting device is used to help complete the hoisting and laying of the bottom plate;

[0067] The embodiment of the present invention also provides a welding method of the above-mentioned semi-trailer bottom plate laser welding device, comprising the following steps:

[0068] Step 1: The frame 400 is hoisted between the first side frame 110 and the second side frame 120 by an external hoisting device. After the hoisting is completed, the frame 400 is pushed until the end of the frame 400 is against the stop bar 150 provided on the second connecting beam 142;

[0069] Step 2: Use the winch equipment on the gantry 200 to hoist and lay the bottom plate above the frame 400, and then cover the frame 400 after the bottom plate is leveled;

[0070] Step 3: Retract the hoisting device, start the welding unit 300, and let the welding robot arm 350 reach the top of the weld to be welded through the cooperation of the first-level sliding seat 310, the second-level sliding seat 320 and the third-level sliding seat 340, so that the sliding movement direction of the third-level sliding seat 340 is parallel to the direction of the weld;

[0071] Step 4: Before the welding operation starts, the bottom plate is supported by adjusting the support component 360, and the length of the telescopic rod 362 in the support component 360 is adjusted according to the data fed back by the measuring instrument 364, so that the adjacent bottom plates are kept relatively flat;

[0072] Step 5. When performing longitudinal welding, the secondary sliding seat 320 rotates, and the tertiary sliding seat 340 moves longitudinally to pull the welding robot arm 350 for welding. When performing transverse welding, the secondary sliding seat 320 rotates, and the tertiary sliding seat 340 moves transversely to pull the welding robot arm 350 for welding.

[0073] It should be noted that, for the above-mentioned embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the described order of actions, because according to the present invention, some steps may be performed in other orders or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0074] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the scope of protection of the invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on these embodiments, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in this field can still combine, add, delete or make other adjustments to the features in the various embodiments of the present invention according to the circumstances without conflict, without making creative work, so as to obtain different other technical solutions that do not deviate from the concept of the present invention in essence, and these technical solutions also belong to the scope of protection of the present invention.

Claims

1. A semi-trailer bottom plate laser welding equipment, characterized in that: include: An operating platform (100) and a gantry (200), wherein the gantry (200) slides on the operating platform (100), and a supporting plate (130) for supporting a vehicle frame (400) is provided on the operating platform (100); A welding unit (300), the welding unit (300) comprising a primary sliding seat (310), a secondary sliding seat (320) and a tertiary sliding seat (340), the primary sliding seat (310) sliding on a gantry (200), the primary sliding seat (310) being rotatably connected to the secondary sliding seat (320), the tertiary sliding seat (340) being provided with a welding mechanical arm (350), the welding mechanical arm (350) sliding on the secondary sliding seat (320) under the traction of the tertiary sliding seat (340); A supporting assembly (360) is provided on the secondary sliding seat (320), and the supporting assembly (360) provides a supporting force to a bottom plate placed on the vehicle frame (400) to maintain the flatness between the bottom plates during the welding process of the welding robot arm (350).

2. A semi-trailer bottom plate laser welding device as claimed in claim 1, characterized in that: The secondary sliding seat (320) comprises a main bearing plate (321), a base (322) and a rotating mechanism (323), wherein the base (322) is arranged in the middle section of the main bearing plate (321), and one end of the rotating mechanism (323) is connected to the base (322), and the other end is connected to the end surface of the primary sliding seat (310) away from the gantry (200); When the third-level sliding seat (340) needs to change the processing direction of the welding robot arm (350), the rotating mechanism (323) changes the relative angle between the second-level sliding seat (320) and the first-level sliding seat (310).

3. The semi-trailer bottom plate laser welding equipment according to claim 2, characterized in that: The number of the abutting components (360) is several groups, and the abutting components (360) include a base (361) fixed on the secondary sliding seat (320), a base rod (363), and a telescopic rod (362) arranged at the end of the base rod (363); the end of the telescopic rod (362) abuts against the periphery of the part to be welded; The base (361) is provided with a measuring instrument (364), and when different measuring instruments (364) obtain different distance data, the corresponding abutting assembly (360) applies pressure to the bottom plate through the telescopic rod (362) to ensure that the bottom plate is in a relatively flat state.

4. A semi-trailer bottom plate laser welding device as claimed in claim 3, characterized in that: The gantry (200) comprises a main beam (210) and a sliding frame (220), the main beam (210) being provided with a screw transmission unit, the primary sliding seat (310) being connected to the screw transmission unit, the screw transmission unit driving the welding unit (300) to move laterally along the frame (400), and the sliding frame (220) to move longitudinally along the frame (400).

5. The semi-trailer bottom plate laser welding equipment as claimed in claim 4, characterized in that: The three-stage sliding seat (340) is provided with a linear motor slider (341) and a guide slider (342); A linear motor (330) is provided on the end face of the main bearing plate (321) away from the primary sliding seat (310), and the linear motor slider (341) slides in a track groove provided on the linear motor (330). A guide groove (325) is also provided on the end face of the main bearing plate (321) away from the primary sliding seat (310), and the guide slider (342) slides in the guide groove (325).

6. The semi-trailer bottom plate laser welding equipment according to claim 5, characterized in that: The main beam (210) is provided with a lead screw guide groove (211) and a sliding guide rail (212), and a lead screw for driving the primary sliding seat (310) to move is provided in the lead screw guide groove (211); The end surface of the primary sliding seat (310) away from the secondary sliding seat (320) is provided with a movable slider and a directional guide groove, and the primary sliding seat (310) slides on the sliding guide rail (212) through the directional guide groove; the movable slider extends into the lead screw guide groove (211) and is assembled on the lead screw.

7. The semi-trailer bottom plate laser welding equipment according to claim 6, characterized in that: The operating table (100) comprises a first side frame (110) and a second side frame (120), wherein the first side frame (110) and the second side frame (120) are connected by a first connecting beam (141) and a second connecting beam (142); The supporting plates (130) are provided in two groups, which are respectively arranged on the first side frame (110) and the second side frame (120); the supporting plates (130) support the vehicle frame (400) located between the first side frame (110) and the second side frame (120).

8. The semi-trailer bottom plate laser welding equipment according to claim 7, characterized in that: The number of the sliding frames (220) is two groups, and the ends of the different sliding frames (220) slide on the tops of the first side frame (110) and the second side frame (120) respectively, and guide rails are provided.

9. A welding method for a semitrailer bottom plate laser welding device as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1: The vehicle frame (400) is hoisted between the first side frame (110) and the second side frame (120) by an external hoisting device. After the hoisting is completed, the vehicle frame (400) is pushed until the end of the vehicle frame (400) is abutted against a stop bar (150) provided on the second connecting beam (142); Step 2: Using a winch device provided on the gantry (200), hoist and lay a bottom plate above the vehicle frame (400), and then level the bottom plate and cover the vehicle frame (400); Step 3: Retract the hoisting device, start the welding unit (300), and use the cooperation of the first-level sliding seat (310), the second-level sliding seat (320), and the third-level sliding seat (340) to allow the welding robot arm (350) to reach the top of the weld to be welded, and keep the sliding movement direction of the third-level sliding seat (340) parallel to the direction of the weld; Step 4: Before the welding operation starts, the bottom plate is supported by adjusting the support component (360), and the length of the telescopic rod (362) in the support component (360) is adjusted by the data fed back by the measuring instrument (364), so that the adjacent bottom plates are kept relatively flat; Step 5: When performing longitudinal welding, the secondary sliding seat (320) rotates and the tertiary sliding seat (340) moves longitudinally for welding. When performing transverse welding, the secondary sliding seat (320) rotates and the tertiary sliding seat (340) moves transversely for welding.

10. The welding method of the semi-trailer bottom plate laser welding equipment according to claim 9, characterized in that: A hoisting machine platform (370) is also provided on the main beam (210), the hoisting machine equipment is arranged on the hoisting machine platform (370), and the hoisting machine platform (370) is connected to the primary sliding seat (310).

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