Intelligent production line for welding car frame of mine car

Abstract

The application relates to the technical field of heavy engineering machinery welding manufacturing, and discloses a mine car welding frame intelligent production line, which comprises two head-tail positioner bodies, the bottom of the head-tail positioner body is slidably connected to a ground guide rail parallel to the X axis, the guide rail drives the head-tail positioner body to translate along the X axis, a self-excitation type variable-cell clamping system is arranged on the rotary disc of the head-tail positioner body, the self-excitation type variable-cell clamping system comprises a base flange and a variable-cell sliding base body which can slide along the X axis, a pre-tightening locking mechanism is arranged between the base flange and the variable-cell sliding base body, and the pre-tightening locking mechanism is used for rigidly locking the X axis displacement of the variable-cell sliding base body in a normal state. The pre-tightening locking mechanism embedded in the self-excitation type variable-cell clamping system is composed of a disc spring overload valve and a V-shaped energy releasing slot, destructive longitudinal thermal thrust caused by high-energy welding is converted into a transverse unlocking component, and the twisting and distortion of the frame chassis and the tearing risk of the rotary support of the positioner are eliminated.

Description

Technical Field

[0001] This invention relates to the field of heavy engineering machinery welding manufacturing technology, specifically to an intelligent production line for welding car frames for mining trucks. Background Technology

[0002] The chassis frames of heavy equipment such as mining dump trucks are typically welded from ultra-thick steel plates, and their entire manufacturing cycle involves multi-layer, multi-pass welding with extremely high heat input. During this intense thermodynamic alternation process, the massive metal lattice absorbs a huge amount of heat energy, inevitably generating extremely violent thermal expansion thrust along the longitudinal direction of space. Currently, to achieve multi-position welding of workpieces, the industry commonly uses head-and-tail double-turn positioners to suspend and clamp heavy-duty chassis. To overcome the enormous spatial eccentric moment generated by the components during full-position rotation, existing positioner fixtures invariably employ an absolutely locked, rigid clamping mode. However, this uncompromising rigid boundary creates an irreconcilable physical conflict with the macroscopic thermal expansion of the chassis. When the violent thermal stress has nowhere to be released, it not only causes permanent distortion and warping of the chassis base material and completed welds, but the accumulated axial thrust also directly backfires along the fixture onto the machine tool body, easily causing the internal raceways of precision slewing bearings to crack or the gears of the reducer to collapse, resulting in devastating damage to expensive heavy equipment.

[0003] This over-reliance on rigid anchoring has also led to another insurmountable technological bottleneck. To obtain sufficient clamping friction, the clamping flanges and front-end modules are often designed to be extremely large. This is like putting heavy physical shackles on the front and rear of the chassis, causing large areas of core stress-bearing areas such as the end plates of the chassis to be obscured, creating structural blind spots that multi-axis automated welding robotic arms simply cannot access. If one attempts to release the clamps on the production line to open up the blind spots, the primary prerequisite is that there must be a support system at the bottom that can perfectly take over the suspended heavy load. However, traditional hydraulic or simple pneumatic lifting mechanisms can only provide rigid vertical thrust. Faced with the complex chassis with its undulating height and numerous reinforcing ribs, traditional jacks are prone to falling into the "island" effect of uneven stress, and the slightest carelessness can lead to local collapse or overturning and slippage of the workpiece. More insidious and fatal is that when welding in the end blind spots causes new heat input, or when the entire vehicle enters a long post-weld cooling period, the heavy chassis will inevitably undergo drastic expansion and contraction displacement in the X-axis longitudinal direction. At this point, if the bottom support system remains firmly attached to the chassis, the rigid hydraulic rod bearing the vertical weight will instantly transform into an obstacle preventing thermal deformation, thereby bearing extremely destructive lateral shear stress. This physical interference is enough to sever the thick support rod at its root.

[0004] Furthermore, the entire process chain faces an even more challenging re-locking dilemma after blind zone welding is completed. The sudden, localized high temperatures in the end areas inevitably cause expansion and distortion of the frame end plates. When the previously retreated single-sided positioner attempts to close again to continue subsequent production line operations, the traditional CNC machine tools, relying on a rigid absolute coordinate system, completely lose their adaptive tolerance capabilities in the face of the drastically altered physical boundaries. The cold, impersonal actuators can only forcibly impact and rigidly compress the deformed frame end face according to the originally set "zero point." This not only fails to rebuild the high-precision flange positioning reference but also directly induces catastrophic secondary mechanical compression damage, causing the originally efficient automated production line to completely lose its continuous operation capability due to frequent physical jams and manual intervention. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an intelligent production line for welding mine car frames. It solves the problems of thermal stress accumulation and physical tearing of equipment caused by absolute rigid anchoring during the processing of heavy steel structures under extreme heat input. It breaks through the barrier of automated welding in the core stress area at the end caused by the obstruction of traditional giant clamps. At the same time, it overcomes the mechanical contradiction that the bottom pipe support mechanism cannot take into account the three-dimensional curved surface contouring of the chassis and the decoupling and wandering of longitudinal thermal deformation when bearing heavy objects. It fundamentally eliminates the destructive squeezing interference caused by the local geometric distortion of the workpiece under alternating working conditions to the stress-free secondary relocking of the automated production line.

[0006] To achieve the above objectives, the present invention provides the following technical solution: an intelligent production line for welding mine car frames, comprising two head and tail positioner bodies. The bottom of the head and tail positioner bodies is slidably connected to a ground guide rail laid parallel to the X-axis, and is driven by the guide rail to translate along the X-axis. A self-excited variable cell clamping system is provided on the rotary table of the head and tail positioner bodies. The self-excited variable cell clamping system includes a base flange and a variable cell sliding base that can slide along the X-axis. A pre-tightening locking mechanism is provided between the base flange and the variable cell sliding base. The pre-tightening locking mechanism is used to rigidly lock the X-axis displacement of the variable cell sliding base under normal conditions, and under conditions greater than... The system unlocks when the X-axis longitudinal thermal thrust reaches a set threshold, allowing the variable-cell sliding matrix to retract and release energy along the X-axis. A phase change array support bed is installed in the bottom area between the two head and tail positioner bodies. It has the degree of freedom to globally lift and lower along the Z-axis and perform three-dimensional geometric contouring of the chassis, as well as the degree of freedom to slide and follow along the X-axis. Welding execution systems are arranged on both sides of the phase change array support bed. These systems are used to perform welding operations on the chassis when the self-excited variable-cell clamping system and the phase change array support bed work together to constrain the three-dimensional spatial coordinates of the chassis. When the head and tail positioner bodies on one side retract outward along the X-axis, they can penetrate into the exposed end area of ​​the chassis to perform blind zone relay welding.

[0007] Preferably, one side of the base flange is fixedly connected to the rotary table of the head and tail positioner body by bolts, and the other side is provided with a female dovetail groove parallel to the X-axis. The variable cell sliding base body has an integrally formed male dovetail protrusion matching the female dovetail groove on the side facing the base flange. The male dovetail protrusion passes through and slides in the female dovetail groove. The spatial rotational degree of freedom and other translational degrees of freedom are locked by a physical inverted structure, allowing the variable cell sliding base body to only translate and slide along the direction of the female dovetail groove. A clamping device is provided on the other side of the variable cell sliding base body.

[0008] Preferably, the pre-tightening locking mechanism includes a disc spring overload valve disposed inside the blind hole on the side of the base flange, a wedge-driven locking pin that is laterally pushed by the disc spring overload valve, and a V-shaped energy release groove embedded in the side of the variable cell sliding base. In the rigid locking state, the end of the wedge-driven locking pin is pressed into the V-shaped energy release groove. When the lateral component of the X-axis longitudinal thermal thrust borne by the variable cell sliding base is converted into a force on the V-shaped inclined surface, which is greater than the pre-tightening force of the disc spring overload valve, the wedge-driven locking pin is forced out of the V-shaped energy release groove to unlock.

[0009] Preferably, the self-excited variable cell clamping system further includes a guide push rod and a main return spring arranged parallel to the X-axis. One end of the guide push rod is fixedly connected to the outer wall of the variable cell sliding base, and the other end passes coaxially through the spring guide hole inside the base flange and is fixedly connected to a limit nut. The main return spring is sleeved outside the guide push rod and continuously applies an elastic thrust away from the base flange to the variable cell sliding base. In a non-forced and unobstructed state, the main return spring pushes the variable cell sliding base to the pre-extended position limited by the limit nut. At this time, the V-shaped energy release slot is displaced forward, causing the wedge actuation locking pin to exit the V-shaped energy release slot and press against the side wall of the variable cell sliding base.

[0010] Preferably, the self-excited variable cell clamping system further includes a displacement sensor disposed inside the base flange, which is used to monitor the lateral physical displacement of the wedge actuating locking pin, and when the wedge actuating locking pin falls into the V-shaped energy release slot from the unlocked state of the pressing side wall, it sends an absolute zero gap locking trigger signal to the main control PLC, thereby serving as an electrical trigger source for cutting off the feed power of the head and tail positioner body along the X-axis.

[0011] Preferably, the phase change array support bed includes a base, and a matrix of multiple lifting cylinders are fixedly connected to the upper part of the base. The output end of the lifting cylinder is connected to a particle airbag containing dry friction spherical particles. In the low-pressure bottom-exploration mode, the lifting cylinder drives the particle airbag to rise and fit against the chassis. The particle airbag is connected to a vacuum pipeline. By evacuating the internal air, the particle airbag undergoes a dry friction phase change and hardens into a rock-like support block conforming to the chassis.

[0012] Preferably, the lifting cylinder is externally integrated with a mechanical piston rod locking device triggered by a pneumatic control command. This device is triggered instantaneously when the particulate airbag undergoes dry friction phase transformation hardening, physically locking the piston rods of all lifting cylinders in the current Z-axis coordinate.

[0013] Preferably, a displacement component that allows sliding along the X-axis is connected in series between the output end of the lifting cylinder and the bottom of the particle airbag. After the Z-axis stroke of the phase change array support bed is physically locked, the hardened particle airbag is allowed to slide along the X-axis following the longitudinal thermal expansion and contraction physical deformation caused by the temperature change of the vehicle frame.

[0014] This invention provides an intelligent production line for welding mine car frames. It has the following beneficial effects: 1. This invention, by embedding a pre-tightening locking mechanism consisting of a disc spring overload valve and a V-shaped energy release groove within a self-excited variable-cell clamping system, transforms the destructive longitudinal thermal thrust caused by high-energy welding into a lateral unlocking force. Once the thermal stress approaches the equipment's tolerance limit, the clamp instantly reduces its dimensions and releases the X-axis unidirectional sliding degree of freedom, smoothly dissolving the accumulated internal stress into mechanical displacement, fundamentally eliminating the risk of torsional distortion of the chassis frame and tearing of the positioner's slewing bearing. Simultaneously, relying on the mechanical pre-extension characteristics of the main return spring, the clamp sliding base, like a physical probe, first contacts the chassis end plate during docking, actively absorbing accumulated manufacturing tolerances and post-weld warping deformation through passive compression stroke; the displacement sensor only issues a locking stop signal at the zero-gap moment when the locking pin precisely falls into the groove, achieving stress-free perfect clamping based on the workpiece's true physical boundaries; 2. This invention utilizes a phase change array support bed to seamlessly mold and wrap the complex undulations of the chassis using low-pressure granular airbags. A vacuum instantly induces dry friction phase change, achieving rapid rock-like hardening. A synchronously triggered mechanical locking device completely eliminates the inherent compressibility defects of the air circuit system, physically locking the piston rod at the current Z-axis coordinate, ensuring that the heavy-duty chassis, weighing tens of tons, does not experience any millimeter-level vertical settlement after the loss of traction from the end clamps. Simultaneously, a bidirectional low-resistance sliding displacement component is cleverly connected between the cylinder piston rod and the bottom of the phase change airbag, transforming the hardened airbag, tightly engaged at the bottom of the chassis, into an independent sliding module. When the massive steel structure experiences severe longitudinal thermal expansion and contraction due to high heat input or a sudden temperature drop, this mechanism allows the support block to move synchronously with the chassis deformation, completely severing the longitudinal thermal stress shear transmission path that could easily break the cylinder guide rod. Attached Figure Description

[0015] Figure 1 This is a three-dimensional schematic diagram of the present invention; Figure 2 This is a front view schematic diagram of the head and tail positioner bed in this invention; Figure 3 for Figure 2Enlarged view of point A in the middle; Figure 4 This is a top cross-sectional view of the self-excited variable cell clamping system in this invention; Figure 5 This is a three-dimensional schematic diagram of the phase change array support bed in this invention; Figure 6 This is a schematic diagram showing the position of the displacement component in this invention.

[0016] The components include: 1. Head and tail positioner bed; 2. Self-excited variable cell clamping system; 201. Base flange; 2011. Female dovetail groove; 2012. Spring guide hole; 202. Variable cell sliding base; 2021. Male dovetail protrusion; 203. Disc spring overload valve; 204. Wedge actuation locking pin; 205. V-shaped energy release slot; 206. Guide push rod; 207. Main return spring; 208. Limit nut; 209. Clamping device; 3. Phase change array support bed; 301. Base; 302. Lifting cylinder; 303. Particle airbag; 304. Displacement assembly. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Please see the appendix Figure 1 - Appendix Figure 6This invention provides an intelligent production line for welding mine car frames. It aims to eliminate inherent defects in heavy steel structures caused by absolute rigid anchoring under extreme heat input, such as chassis torsion, physical tearing of equipment, and blind spots in end-operation areas, through a hardware system with multi-physics field collaborative decoupling. The production line includes two head and tail positioner bodies 1, whose bottoms are slidably connected to ground guide rails laid parallel to the X-axis. The guide rails drive the head and tail positioner bodies to translate along the X-axis. A self-excited variable cell clamping system 2 is installed on the rotary table of the head and tail positioner bodies 1. The self-excited variable cell clamping system 2 includes a base flange 201 and a variable cell sliding base 202 that can slide along the X-axis. A pre-tightening locking mechanism is provided between the base flange 201 and the variable cell sliding base 202. The pre-tightening locking mechanism is used to rigidly lock the X-axis displacement of the variable cell sliding base 202 under normal conditions and unlocks it when subjected to a longitudinal thermal thrust exceeding a set threshold along the X-axis. The variable cell sliding matrix 202 is allowed to release energy by retracting along the X-axis. A phase change array support bed 3 is set in the bottom area between the two head and tail positioner bodies 1. It has the degree of freedom to lift and lower the entire frame along the Z-axis and perform three-dimensional geometric contouring of the chassis, as well as the degree of freedom to slide and follow along the X-axis. Welding execution systems are arranged on both sides of the phase change array support bed 3. When the self-excited variable cell clamping system 2 and the phase change array support bed 3 work together to constrain the three-dimensional spatial coordinates of the frame, the system performs welding operations on the frame. When the head and tail positioner bodies 1 on one side retract outward along the X-axis, the system probes into the exposed end area of ​​the frame to perform blind zone relay welding.

[0019] The overall construction and macro-operation logic of the intelligent production line for welding mine car frames includes the following steps: First, establish the global three-dimensional physical coordinate system and basic support structure of the intelligent production line. Parallel heavy-duty ground guide rails are anchored and laid on the surface of the production line foundation. The longitudinal extension direction of these heavy-duty ground guide rails is strictly defined as the X-axis of this system. Simultaneously, the direction perpendicular to the gravity normal to the ground surface is defined as the Z-axis, and the horizontal direction perpendicular to the plane of the X-axis and Z-axis is defined as the Y-axis.

[0020] Secondly, the head and tail positioner beds 1 are mounted and slidably installed on heavy-duty ground guide rails. The two head and tail positioner beds 1 are arranged in a mirror-image opposite manner along the X-axis, and each has a high-precision servo feed transmission assembly integrated at the bottom. The two devices can independently receive displacement pulse commands from the central control PLC and perform opposite closed-path propulsion or opposite large-stroke retraction sliding along the X-axis.

[0021] Next, a high-torque rotary table is coaxially mounted on the vertical surface of each head and tail positioner bed 1 facing the center. The high-torque rotary table is rigidly coupled with the internal heavy-duty slewing bearing and reducer unit to overcome the spatial eccentric moment of heavy components after the end engagement with the frame, providing multi-attitude, all-attitude spatial rotation power around the X-axis.

[0022] Subsequently, the welding execution system is arranged in a matrix along the side area of ​​the heavy-duty ground guide rail. The welding execution system includes a cluster of multi-axis welding robots controlled by a central PLC. The bottom of the multi-axis welding robot cluster is anchored to an independent side station offset from the X-axis main line, and the end effector radius of its robotic arms is set to fully cover the suspended welding operation area between the two head-tail positioner bodies.

[0023] Finally, the collaborative avoidance logic between the head and tail positioner machine bed 1 and the multi-axis welding robot cluster in the spatiotemporal dimensions was established. During the large-span welding stage of the main frame structure, the two head and tail positioner machine beds 1 advanced along the X-axis to the limit closed coordinate, clamping the frame in mid-air, and the multi-axis welding robot cluster performed high-energy multi-layer and multi-pass welding on the exposed web and main beam in the middle section of the frame.

[0024] During the single-sided blind spot elimination phase, the head and tail positioner bed 1 on one side releases the clamping force and slides outward along the X-axis for a set stroke. With the physical removal of the machine bed, the space at the head and tail ends of the frame, previously physically obscured by the flange and fixture housing, is completely released. The robotic arms of the multi-axis welding robot cluster, following programmed instructions, penetrate into this open area and perform a full-area welding operation on the remaining relay weld seam.

[0025] One side of the base flange 201 is fixedly connected to the rotary table of the head and tail positioner body 1 by bolts, and the other side is provided with a female dovetail groove 2011 parallel to the X-axis. The variable cell sliding base 202 is integrally formed with a male dovetail protrusion 2021 matching the female dovetail groove 2011 on the side facing the base flange 201. The male dovetail protrusion 2021 passes through and slides in the female dovetail groove 2011. The spatial rotational degree of freedom and other translational degrees of freedom are locked by a physical inverted structure, allowing the variable cell sliding base 202 to only translate and slide along the direction of the female dovetail groove 2011. A clamping device 209 is provided on the other side of the variable cell sliding base 202.

[0026] The pre-tightening locking mechanism includes a disc spring overload valve 203 disposed inside the lateral blind hole of the base flange 201, a wedge-driven locking pin 204 pushed laterally by the disc spring overload valve 203, and a V-shaped energy release groove 205 embedded in the side of the variable cell sliding base 202. In the rigid locking state, the end of the wedge-driven locking pin 204 is pressed into the V-shaped energy release groove 205. When the lateral component of the X-axis longitudinal thermal thrust borne by the variable cell sliding base 202 is converted into a force on the V-shaped inclined surface, which is greater than the pre-tightening force of the disc spring overload valve 203, the wedge-driven locking pin 204 is forced out of the V-shaped energy release groove 205 to unlock.

[0027] The self-excited variable cell clamping system 2 also includes a guide push rod 206 and a main return spring 207 arranged parallel to the X-axis. One end of the guide push rod 206 is fixedly connected to the outer wall of the variable cell sliding base 202, and the other end passes coaxially through the blind hole inside the base flange 201 and is fixedly connected to the limit nut 208. The main return spring 207 is sleeved on the outside of the guide push rod 206 and continuously applies an elastic thrust away from the base flange 201 to the variable cell sliding base 202. In the unforced and unobstructed state, the main return spring 207 pushes the variable cell sliding base 202 to the pre-extended position defined by the limit nut 208. At this time, the V-shaped energy release groove 205 is displaced forward, causing the wedge actuation locking pin 204 to exit the V-shaped energy release groove 205 and press against the side wall of the variable cell sliding base 202.

[0028] The self-excited variable cell clamping system 2 also includes a displacement sensor installed inside the base flange 201, which is used to monitor the lateral physical displacement of the wedge actuation locking pin 204. When the wedge actuation locking pin 204 falls into the V-shaped energy release slot 205 from the unlocked state of the pressure side wall, it sends an absolute zero gap locking trigger signal to the main control PLC, which serves as the electrical trigger source for cutting off the feed power of the head and tail positioner bed 1 along the X-axis.

[0029] In this embodiment, the rotary tables of the two head-and-tail positioner bodies 1 are each equipped with a self-excited variable-cell clamping system. The main body of this system consists of a base flange 201 and a variable-cell sliding base 202 that can slide along the X-axis. The base flange 201 and the variable-cell sliding base 202 are slidably engaged by a female dovetail groove 2011 and a male dovetail protrusion 2021 parallel to the X-axis. This engagement ensures an extremely low coefficient of sliding friction along the X-axis while providing an absolutely reliable bending and torsional bearing boundary for the heavy-duty frame during multi-positional tilting.

[0030] A clamping device 209 is installed on the variable-cell sliding base 202. This device employs a split upper and lower clamping jaw, designed to provide a semi-open physical clearance space for welding in the blind zone at the ends. The split upper and lower clamping jaw consists of a bottom rigid support plate fixed below and a top vertical hydraulic clamping plate controlled by a hydraulic circuit. Upon receiving a release command, the top vertical hydraulic clamping plate lifts in the opposite direction along the Z-axis, completely releasing the vertical physical engagement with the frame end plate. At this point, the variable-cell sliding base 202 can be pulled away and retracted along the X-axis outwards with the entire head and tail positioner body 1 without any Z-axis interference, thus exposing a large area of ​​the frame end plate area previously covered by the clamp housing.

[0031] To establish rigid clamping under normal conditions and cope with extreme thermal stress, a pre-tightening locking mechanism is integrated between the base flange 201 and the variable-cell sliding base 202. A lateral blind hole is laterally formed inside the solid body of the base flange 201, and a high-rigidity disc spring overload valve 203 is connected in series deep within the blind hole. Driven laterally by the disc spring overload valve 203, a wedge-driven locking pin 204 is guided and slidably mounted on the outer side of the blind hole. Corresponding to the spatial coordinates of this locking pin, a V-shaped energy release groove 205 made of high-hardness alloy steel is embedded on the mating side of the variable-cell sliding base 202, and the end of the wedge-driven locking pin 204 is synchronously machined into a perfectly aligned V-shaped bevel.

[0032] Under the normal boundary between room temperature feeding and conventional suspended flipping welding, the pre-tightening locking mechanism is in a rigid locked state. The huge pre-tightening force released by the disc spring overload valve 203 presses the V-shaped end of the wedge-driven locking pin 204 firmly into the bottom of the V-shaped energy release groove 205. This lateral engagement force completely locks the X-axis degree of freedom of the variable-cell sliding base 202 sliding along the female dovetail groove 2011, making the entire self-excited variable-cell clamping system 2 like an absolutely rigid single flange, stably transmitting the spatial eccentric torque output by the high-torque rotary table.

[0033] When high-energy multi-layer, multi-pass welding drives the frame lattice to absorb a great deal of heat, the entire frame undergoes a violent longitudinal physical expansion along the X-axis. This longitudinal thermal thrust along the X-axis acts entirely on the variable-cell sliding matrix 202 that is in contact with it. At this time, the inclined sidewall of the V-shaped energy release groove 205 acts as a purely mechanical vector force converter, precisely converting the longitudinal thrust borne by the variable-cell sliding matrix 202 into a lateral pushing force that compresses the wedge-driven locking pin 204 to retract. As the welding heat continues to accumulate, once this lateral force exceeds the preload threshold set by the disc spring overload valve 3, the wedge-driven locking pin 204 is forced out of the V-shaped energy release groove 205. The variable-cell sliding matrix 202 then regains its unidirectional sliding freedom and slides backward along the dovetail groove 2011, smoothly releasing the catastrophic thermal thrust inside the frame into mechanical displacement.

[0034] To completely eliminate the forced compression damage during the alignment of heavy components and the secondary relocking after welding, the self-excited variable cell clamping system 2 deeply integrates mechanical energy storage and high-sensitivity sensing technology to construct an active tactile homing mechanism based on the solid boundary. A guide push rod 206 and a main return spring 207 are arranged parallel to the X-axis between the base flange 201 and the variable cell sliding base 202.

[0035] The front end of the guide push rod 206 is rigidly fixed to the back wall of the variable-cell sliding base 202. Its body extends rearward along the X-axis, coaxially passing through a spring guide hole 2012 inside the base flange 201, and a limit nut 208 is screwed onto its rear end. The main return spring 207 is coaxially sleeved on the outer cylindrical surface of the guide push rod 206, confined between the spring guide hole 2012 inside the base flange 201 and the back wall of the variable-cell sliding base 202. At any time during system operation, the main return spring 207 continuously applies a constant forward elastic thrust to the variable-cell sliding base 202.

[0036] In this embodiment, when the clamping device 209 is in an initial state of no load and no physical obstruction at the front end, the elastic potential energy of the main return spring 207 is fully released. This potential energy pushes the variable-cell sliding base 202 forward along the female dovetail groove 2011 until it is physically and rigidly limited by the tail limiting nut 208 and stops. At this time, the variable-cell sliding base 202 is in the pre-extended position preset by the system structure dimensions. As the base moves forward as a whole, the V-shaped energy-releasing groove 205 embedded on its side undergoes a forward misalignment in the X-axis. The misalignment causes the wedge-head actuating locking pin 204, which was originally facing the groove, to lose its groove space, and the V-shaped end of the locking pin is forced out of the groove and instead presses tightly against the flat, high-hardness sidewall of the variable-cell sliding base 202.

[0037] To accurately capture the microscopic displacement dynamics of the wedge-actuated locking pin 204 and convert it into macroscopic control commands, a high-frequency displacement sensor is hidden inside the base flange 201, directly opposite the cavity sidewall covering the wedge-actuated locking pin 204. The sensor's sensing end face maintains a small sensing gap with the cylindrical side surface of the locking pin. When the system is in the aforementioned pre-extended position, the locking pin presses against the sidewall, reaching its maximum retracted state, and the sensor outputs a normal reference level signal.

[0038] In this embodiment, when the head-to-tail positioner body 1, carrying the self-excited variable cell clamping system 2 in the pre-extended position, advances and closes along the X-axis towards the center, the front end face of the variable cell sliding base 202, like a physical probe, first contacts the rough end plate of the suspended frame. As the machine tool's feed power continues to be output, the massive frame structure forces the variable cell sliding base 202 to overcome the thrust of the main return spring 207 and move backward relative to the dovetail groove 2011. During this passive retraction process, the thickness tolerance, welding deformation, and minute assembly gaps of the frame end plate are all absorbed by the compression stroke of the spring.

[0039] When the backward displacement of the variable-cell sliding base 202 precisely offsets all manufacturing tolerances and pre-extension allowances, the V-shaped energy-releasing groove 205 on its side will once again precisely align with the center coordinates of the lateral blind hole. Driven by the disc spring overload valve 203, the end of the wedge-actuated locking pin 204 cuts into the bottom of the V-shaped energy-releasing groove 205. The displacement sensor captures this physical displacement of the locking pin and sends an absolute zero-gap locking trigger signal to the main control PLC in the microsecond instant of the pin's descent into the groove. After receiving this high-level signal, the PLC instantly cuts off the X-axis servo feed power of the head and tail positioner bed 1, thereby completing stress-free clamping and alignment based on the actual boundary of the workpiece.

[0040] The phase change array support bed 3 includes a base 301. Multiple sets of lifting cylinders 302 arranged in a matrix are fixedly connected to the upper part of the base 301. The output end of the lifting cylinder 302 is connected to a particle airbag 303 containing dry friction spherical particles. In the low-pressure bottoming mode, the lifting cylinder 302 drives the particle airbag 303 to rise and fit against the chassis. The particle airbag 303 is connected to a vacuum pipeline. By evacuating the internal air, the particle airbag 303 undergoes a dry friction phase change and hardens into a rock-like support block conforming to the chassis.

[0041] The lifting cylinder 302 has an integrated mechanical piston rod locking device that is triggered by a pneumatic control command. It is triggered at the instant that the particulate airbag 303 undergoes dry friction phase transformation hardening, and physically locks the piston rods of all lifting cylinders 302 in the current Z-axis coordinate.

[0042] Between the output end of the lifting cylinder 302 and the bottom of the particle airbag 303, a displacement component 304 that allows sliding along the X-axis is connected in series. After the Z-axis stroke of the phase change array support bed 3 is physically locked, the hardened particle airbag 303 is allowed to slide along the X-axis following the longitudinal thermal expansion and contraction physical deformation caused by the temperature change of the vehicle frame.

[0043] The phase change array support bed 3, located in the bottom region between the head and tail positioner bodies 1, constructs an anisotropic load-bearing structure that combines compliant three-dimensional contouring with absolute rigidity. The main body of the phase change array support bed 3 comprises multiple sets of lifting cylinders 302 arranged in a matrix. Each set of lifting cylinders 302 is connected at its end to a particle airbag 303 containing internally encapsulated dry friction spherical particles. When the system executes the low-pressure bottom-exploration mode, the pneumatic circuit drives the multiple sets of lifting cylinders to rise synchronously at a constant, extremely low air pressure until the outer surface of the flexible particle airbag 303 fully contacts and adaptively conforms to the complex and uneven three-dimensional geometric contours of the vehicle chassis.

[0044] To instantly transform the flexible, contour-following contact into rigid support, the sealed inner cavity of the granular airbag 303 is connected to a vacuum pipeline controlled by a high negative pressure source. Once all the granular airbags 303 have completed low-pressure probing and seamless wrapping of the chassis, the central control PLC issues a phase change trigger command, instantly evacuating the air from inside the granular airbags. Under the strong pressure of external atmospheric pressure, intense physical interlocking and dry friction phase change occur between the dry friction spherical particles inside the airbag, instantly hardening the entire airbag into a rock-like support block that fits perfectly with the local contours of the chassis.

[0045] To completely eliminate the inherent gas compressibility defect of the pneumatic system under heavy loads, a mechanical piston rod lock-up device triggered by pneumatic control commands is integrated into the outer cylinder of the lifting cylinder 302. This mechanical piston rod lock-up device is configured to activate instantaneously during the dry friction phase transformation hardening of the particulate air bladder 303, and uses an internal high-rigidity locking structure to physically lock the piston rods of all lifting cylinders 302 at their current extended Z-axis coordinates. This freezes the absolute spatial elevation of the chassis from the bottom layer of the mechanical structure, ensuring that the heavy-duty chassis does not experience any millimeter-level vertical settlement when the single-sided positioner body 1 and its fixtures are released and retracted.

[0046] Between the top of the piston rod of the lifting cylinder 302 and the bottom base plate of the particulate airbag 303, a displacement component 304 that allows for low-resistance sliding in both directions along the X-axis is connected in series. This displacement component 304 completely separates the transmission of vertical Z-axis compressive stress from horizontal X-axis shear slip through a built-in low-friction coefficient mating surface or linear guide structure.

[0047] After the Z-axis travel of the phase change array support bed 3 is physically locked and the chassis smoothly transitions to the support bed's bearing state, the hardened granular airbags 303 are tightly engaged with the bottom of the chassis like native blocks. When the massive steel structure experiences localized longitudinal thermal expansion due to high-heat relay welding in the end blind zone, or undergoes severe overall longitudinal contraction during the long post-weld cooling period, the displacement component 304 allows the hardened granular airbags 303 to slide bidirectionally along the X-axis, following the longitudinal thermal expansion and contraction caused by the chassis temperature fluctuations. This sliding mechanism completely cuts off the path of the huge longitudinal destructive shear stress generated by drastic temperature changes to the base of the support bed, avoiding the physical interference risk of the piston rod of the lifting cylinder 302 being forcibly bent or cut off.

[0048] Based on the aforementioned hardware architecture of multi-physics field collaborative decoupling, the intelligent production line is configured to execute a strictly closed-loop spatiotemporal collaborative processing method logic. In the initial material loading and alignment stage of the first process, the system executes a locking logic based on tactile search of physical boundaries. The self-excited variable cell clamping system 2, in the pre-extended position, advances along the X-axis towards the center with the head-tail shifting machine body 1. The variable cell sliding base 202 first touches the frame end plate and, under continuous feed power, generates relative retraction along the X-axis, simultaneously compressing the main return spring 207. Until the wedge actuation locking pin 204 precisely falls into the V-shaped energy release slot 205, the central control PLC stops the feed and closes the clamping device 209 based on the absolute zero gap locking trigger signal instantly emitted by the displacement sensor, thereby completing the adaptive absorption of the initial manufacturing tolerances and assembly gaps of the large frame.

[0049] During the large-span welding phase of the main frame structure, the system activates the thermal stress self-excited yielding logic. The welding execution system performs high-energy, multi-layer, multi-pass welding on the frame web and main beam, causing a rapid temperature rise that leads to a dramatic longitudinal expansion of the heavy steel structure lattice. This longitudinal thermal thrust forces the inclined sidewall of the V-shaped energy release slot 205 to convert the longitudinal force into a lateral pushing component. At the instant the preload threshold of the disc spring overload valve 203 is crossed, the wedge-actuated locking pin 204 is forced out of the slot, and the variable-cell sliding matrix 202 immediately gains a unidirectional yielding degree of freedom along the X-axis. This mechanism smoothly transforms the catastrophic thermal stress accumulated inside the frame into mechanical displacement, utilizing purely mechanical topology reduction throughout the process to protect the machine tool slewing bearing from tearing damage.

[0050] After the main area welding is completed, the system switches to the support bed take-off and blind spot exposure logic. The phase change array support bed 3 enters the low-pressure bottoming mode, driving the granular airbags to fully adhere to and contour-wrap the chassis frame. Subsequently, by evacuating the internal air to induce dry friction phase change hardening, and simultaneously triggering the mechanical piston rod locking device, the system physically locks the absolute spatial elevation of the chassis frame on the current Z-axis coordinate. After confirming that the Z-bearing load is smoothly transferred and the gravity is completely taken over by the support bed, the clamping device 209 at the front end of the self-excited variable cell clamping system 2 releases the vertical engagement, and the top vertical hydraulic pressure plate lifts upward, completely detaching from the physical constraint on the chassis end plate.

[0051] After being released from constraints, the single-sided head and tail positioner body 1, along with its self-excited variable-cell clamping system 2, performs a large-stroke sliding retreat along the X-axis outward. This macroscopic retreat action completely exposes the head and tail end areas of the chassis, which were previously tightly wrapped by the clamping flange. The welding execution system located on the side then moves inward, probing into the open end space to perform blind-zone relay welding. During this period, the hardened particulate airbags 303, relying on the displacement components 304 at the bottom, freely move along with the longitudinal physical deformation of the chassis caused by local high heat input or overall cooling, achieving full welding coverage of the core stress-bearing parts of the chassis without any dead angles.

[0052] The concentrated heat input from blind zone welding inevitably causes localized outward expansion deformation of the frame end plate. Therefore, after blind zone welding on one side is completed, the system executes a tolerance-accepting relocking logic. The head and tail positioner body 1 on the retreating side is controlled to feed back towards the frame along the X-axis. The variable cell sliding base 202, which has been pushed back to the pre-extended position by the main return spring 207, again abuts against the newly deformed frame end plate, resulting in forced relative retreat. Until the wedge-actuated locking pin 204 falls back into the V-shaped energy release slot 205 and signals to stop feeding, the system relies entirely on the current physical boundary of the welded frame to determine the final X-axis stop coordinate. It passively accepts the new deformation generated by blind zone welding using the elastic tolerance space inside the clamping device 209, establishing a precise and stress-free secondary relocking reference, ensuring the absolute continuity of subsequent flipping operations on the production line.

[0053] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A smart production line for welding mine car frames, comprising two head and tail positioner machine bodies (1), characterized in that, The head-and-tail positioner bed (1) is slidably connected to a ground guide rail laid parallel to the X-axis at its bottom, and is driven by the guide rail to translate along the X-axis. A self-excited variable cell clamping system (2) is provided on the rotary table of the head-and-tail positioner bed (1). The self-excited variable cell clamping system (2) includes a base flange (201) and a variable cell sliding base (202) that can slide along the X-axis. A pre-tightening locking mechanism is provided between the base flange (201) and the variable cell sliding base (202). The pre-tightening locking mechanism is used to rigidly lock the X-axis displacement of the variable cell sliding base (202) under normal conditions, and unlocks when subjected to a longitudinal thermal thrust of the X-axis greater than a set threshold, allowing The variable cell sliding matrix (202) releases energy by retracting along the X-axis. A phase change array support bed (3) is provided in the bottom area between the two head and tail positioner bodies (1). It has the degree of freedom to lift and lower the entire frame along the Z-axis and perform three-dimensional geometric contouring on the chassis, as well as the degree of freedom to slide and follow along the X-axis. Welding execution systems are arranged on both sides of the phase change array support bed (3). When the self-excited variable cell clamping system (2) and the phase change array support bed (3) work together to constrain the three-dimensional spatial coordinates of the frame, the system performs welding operations on the frame. When the head and tail positioner bodies (1) on one side retract outward along the X-axis, the system probes into the exposed end area of ​​the frame to perform blind zone relay welding.

2. The intelligent production line for welding mine car frames according to claim 1, characterized in that, One side of the base flange (201) is fixedly connected to the rotary table of the head and tail positioner body (1) by bolts, and the other side is provided with a female dovetail groove (2011) parallel to the X-axis. The variable cell sliding base (202) is integrally formed with a male dovetail protrusion (2021) matching the female dovetail groove (2011) on the side facing the base flange (201). The male dovetail protrusion (2021) passes through and slides in the female dovetail groove (2011). The spatial rotational degree of freedom and other translational degrees of freedom are locked by the physical inverted structure. Only the variable cell sliding base (202) is allowed to translate and slide along the direction of the female dovetail groove (2011). The other side of the variable cell sliding base (202) is provided with a clamping device (209).

3. The intelligent production line for welding mine car frames according to claim 2, characterized in that, The pre-tightening locking mechanism includes a disc spring overload valve (203) disposed inside the lateral blind hole of the base flange (201), a wedge-driven locking pin (204) pushed laterally by the disc spring overload valve (203), and a V-shaped energy release groove (205) embedded in the side of the variable cell sliding base (202). In the rigid locking state, the end of the wedge-driven locking pin (204) is pressed into the V-shaped energy release groove (205). When the longitudinal thermal thrust of the X-axis borne by the variable cell sliding base (202) is converted into a lateral component force on the V-shaped inclined surface, which is greater than the pre-tightening force of the disc spring overload valve (203), the wedge-driven locking pin (204) is forced out of the V-shaped energy release groove (205) to unlock.

4. The intelligent production line for welding mine car frames according to claim 3, characterized in that, The self-excited variable cell clamping system (2) further includes a guide push rod (206) and a main return spring (207) arranged parallel to the X-axis. One end of the guide push rod (206) is fixedly connected to the outer wall of the variable cell sliding base (202), and the other end coaxially passes through the spring guide hole (2012) inside the base flange (201) and is fixedly connected to a limit nut (208). The main return spring (207) is sleeved on the outside of the guide push rod (206). And continuously apply an elastic thrust away from the base flange (201) to the variable cell sliding base (202). In the unforced and unobstructed state, the main return spring (207) pushes the variable cell sliding base (202) to the pre-extended position defined by the limit nut (208). At this time, the V-shaped energy release groove (205) is displaced forward, so that the wedge actuation locking pin (204) exits the V-shaped energy release groove (205) and presses against the side wall of the variable cell sliding base (202).

5. The intelligent production line for welding mine car frames according to claim 3, characterized in that, The self-excited variable cell clamping system (2) also includes a displacement sensor installed inside the base flange (201), which is used to monitor the lateral physical displacement of the wedge actuation locking pin (204) and send an absolute zero gap locking trigger signal to the main control PLC when the wedge actuation locking pin (204) falls into the V-shaped energy release slot (205) from the unlocked state of the pressure side wall, thereby serving as the electrical trigger source for cutting off the feed power of the head and tail positioner body (1) along the X-axis.

6. The intelligent production line for welding mine car frames according to claim 1, characterized in that, The phase change array support bed (3) includes a base (301), and a matrix of multiple lifting cylinders (302) are fixedly connected to the upper part of the base (301). The output end of the lifting cylinder (302) is connected to a particle airbag (303) containing dry friction spherical particles. In the low-pressure bottoming mode, the lifting cylinder (302) drives the particle airbag (303) to rise and fit against the chassis. The particle airbag (303) is connected to a vacuum pipeline. By evacuating the internal air, the particle airbag (303) undergoes a dry friction phase change and hardens into a rock-like support block conforming to the chassis.

7. The intelligent production line for welding mine car frames according to claim 6, characterized in that, The lifting cylinder (302) is externally integrated with a mechanical piston rod locking device triggered by a pneumatic control command. It is triggered at the instant of the dry friction phase transformation hardening of the particulate air bag (303) to physically lock the piston rods of all lifting cylinders (302) on the current Z-axis coordinate.

8. The intelligent production line for welding mine car frames according to claim 7, characterized in that, Between the output end of the lifting cylinder (302) and the bottom of the particle airbag (303), a displacement component (304) that allows sliding along the X-axis is connected in series. After the Z-axis stroke of the phase change array support bed (3) is physically locked, the hardened particle airbag (303) is allowed to slide along the X-axis following the longitudinal thermal expansion and contraction physical deformation caused by the temperature change of the frame.

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