Integral pendant pre-arrangement platform hydraulic control system and method

Abstract

The application discloses a kind of integral sling pre-arrangement platform hydraulic control system and method, belong to rail transit electromechanical liquid precision control technical field.System uses public oil source+six independent parallel open hydraulic branch architecture, supporting oil source power unit, public auxiliary protection unit, six groups of modular work station execution branch and PLC electric control unit;Each work station differentiates and configures throttle, stepped pressure regulating element, branch built-in hydraulic control one-way valve, cooperate main oil line accumulator, oil cooler and construct two-way locking, dynamic pressure compensation, constant temperature and pressure loop.The application is original mechanical limit, servo negative tolerance cutting, continuous tension error directional transfer process: one side return line is mechanically limited to calibrate reference length, servo hanging column is first operated to theoretical total length negative tolerance position and then cut, so that wire actual length is slightly short;After servo rigid lock main sling size, push cylinder continuous tension will cut, assembly, wire elastic deformation all error be transferred to return section without accuracy requirement.

Description

Technical Field

[0001] This invention belongs to the field of high-end intelligent equipment and electromechanical-hydraulic automation precision control technology for rail transit, specifically relating to a hydraulic control system and method for an integrated dropper pre-assembly platform. Background Technology

[0002] The overhead contact system of electrified railways provides traction power to trains. The integral dropper is a crucial load-bearing and current-conducting component of the contact system, consisting of the main dropper and the return wires at both ends. According to railway acceptance standards, the return wires at both ends do not require high-precision dimensional control and can be pre-processed with a uniform length. However, the dimensional tolerances, crimping quality, and tension stress requirements for the main dropper are extremely stringent. Its processing accuracy directly affects the stability of the pantograph-catenary contact and is related to train operation safety.

[0003] The intelligent prefabrication of integrated droppers includes automated processes such as wire cutting, tensioning and length setting, station sliding, and pipe crimping. All equipment actuators are driven by hydraulic systems. The pressure accuracy, pressure holding capacity, and multi-station coordination of these hydraulic systems directly determine the finished dropper pass rate. Currently, conventional dropper prefabrication hydraulic systems have several design shortcomings, hindering precise mass production and failing to meet the high standards required for on-site construction.

[0004] The existing equipment cannot compensate for various errors generated during wire feeding, cutting, tooling slippage, and elastic deformation of the wire during processing. Furthermore, it lacks error transfer compensation based on the characteristics of the dropper structure, resulting in all errors accumulating in the main dropper and leading to poor dimensional consistency in the finished product. Simultaneously, the equipment's hydraulic circuit relies solely on the neutral-position sealing of the directional valve to lock the cylinder, lacking a dedicated locking and pressure-reducing structure. Internal leakage in the cylinder causes continuous pressure decay during the pressure-holding phase, easily leading to tooling displacement, wire retraction, and quality defects such as out-of-specification dimensions and incomplete crimping.

[0005] In addition, traditional equipment uses a single-path shared hydraulic circuit, causing interference between the actions of each working cylinder. This prevents differentiated pressure control for different processes such as shearing, clamping, and high-pressure crimping, resulting in insufficient operational stability. The system lacks oil temperature monitoring and cooling devices; prolonged operation leads to increased oil temperature, altering oil viscosity and inducing system pressure fluctuations, further increasing processing errors. Furthermore, the entire system relies heavily on manual adjustment of operating parameters; in open-loop control mode, human error cannot be eliminated, resulting in low overall automation control accuracy.

[0006] In summary, existing hydraulic control systems cannot solve practical problems such as large deviations in dropper dimensional accuracy, unstable crimping quality, interference in oil circuits at different workstations, and lack of pressure and oil temperature control. Therefore, there is an urgent need in this field to develop a hydraulic control system with multi-station independent pressure control, long-term pressure holding, constant oil temperature control, and error transfer technology. This system should be optimized in both hardware circuitry and control logic to meet the high-precision, automated, and standardized prefabrication requirements of railway catenary dropper production. Summary of the Invention

[0007] The purpose of this invention is to overcome the technical defects of existing intelligent prefabrication equipment hydraulic systems, such as poor pressure holding performance, easy pressure decay, serious interference in multi-station oil circuits, lack of graded precise and adjustable pressure, lack of stable oil temperature control, poor accuracy of main body droppers due to the accumulation of traditional process errors, and low degree of automation. This invention provides a hydraulic control system and control method for an integrated dropper prefabrication platform.

[0008] This invention utilizes a multi-station independent parallel modular hydraulic circuit, a differentiated branch adjustable pressure control structure, and an energy storage, pressure replenishment, and hydraulic control one-way valve bidirectional locking and pressure holding structure. It employs a unique process of error-oriented transfer through mechanical limit calibration single-sided return line, servo negative tolerance positioning and cutting, and rigid length-fixed continuous tensioning, combined with electromechanical-hydraulic integrated closed-loop control logic. This achieves long-term pressure holding of the hydraulic system, interference-free station operations, and differentiated precise pressure control. At the same time, it directionally transfers the dimensional errors of the entire process to the low-precision current-carrying ring area, significantly improving the machining accuracy of the main hanger, the consistency of finished products, and the stability of mass production.

[0009] The technical solution of the present invention is as follows: This invention provides a hydraulic control system for an integrated dropper pre-assembly platform, including an oil source power unit, a common auxiliary protection unit, six sets of modular workstation execution branches, and an electrical control unit. The entire system adopts an open parallel hydraulic circuit structure, sharing a common main oil source. The six cylinder branches are arranged independently in parallel without interfering with each other, respectively corresponding to the shearing cylinder, the heart-shaped column telescopic cylinder, the crimping pipe crimping platform push cylinder, the crimping pipe crimping cylinder, the terminal head crimping platform push cylinder, and the terminal head crimping cylinder of the pre-assembly platform, adapting to the coordinated operation of the entire dropper pre-assembly process.

[0010] The oil-powered unit includes an oil tank, air filter, level gauge, hydraulic pump, pressure gauge, and unloading relief valve. The hydraulic pump, as the core power source, draws oil from the tank to provide stable pressure oil for the entire circuit. The unloading relief valve is connected in parallel to the main oil circuit and serves three functions: one-way shut-off, overflow pressure stabilization, and pump unloading. It prevents backflow of pressurized oil and opens to overflow when the system pressure reaches a set value, allowing the hydraulic pump to operate unloaded and achieving system overflow overload protection. The pressure gauge collects and displays the main oil circuit pressure in real time, facilitating real-time monitoring of operating conditions and troubleshooting. The air filter and level gauge are used for oil tank ventilation and dust prevention, and oil level monitoring, respectively.

[0011] The common auxiliary protection unit includes an oil suction filter, a return oil cooler, and an accumulator. The oil suction filter filters impurities in the oil drawn into the tank, protecting the hydraulic pump and valve assembly. The return oil cooler provides forced cooling of the system's return oil, stabilizing the oil temperature and preventing pressure deviations caused by high-temperature deterioration and viscosity fluctuations. The accumulator is connected in parallel to the main oil circuit and works with the unloading relief valve to achieve an energy-saving and pressure-stabilizing mode where the hydraulic pump is unloaded and the accumulator provides pressure replenishment and maintenance, thus suppressing system pressure decay.

[0012] The modular workstation execution branch consists of 6 groups, connected in parallel and independent. Each workstation branch has the same structure and independent control, and all include a solenoid directional valve.

[0013] In the hydraulic control circuit of the overall dropper pre-assembly equipment, differentiated speed regulation and buffering configurations are adopted according to the motion characteristics and process requirements of each actuator cylinder: The shearing cylinder is a full-stroke telescopic shearing cutter cylinder that pushes the cutter to slide and cut the copper stranded wire. There is no hard stop limit, the load is stable during the shearing process, and no additional throttling speed control element is required.

[0014] The heart-shaped column telescopic cylinder drives the heart-shaped mold column to extend and retract vertically within the tooling plate slot. The pressing pipe pressing platform push cylinder is a horizontal sliding drive cylinder for the pressing pipe pressing platform, pushing it closer to the heart-shaped mold column during the pressing process. Both cylinders have hard stops at the end of their movements, which can generate rigid impacts and vibrations during operation, potentially affecting the dimensional accuracy of the hanger pre-fitting and the tooling life. Therefore, double one-way throttle valves are installed on the inlet and return oil branches of the heart-shaped column telescopic cylinder and the pressing pipe pressing platform push cylinder. By adjusting the return oil throttling speed, the extension and retraction speeds of the cylinders are controlled separately, achieving a smooth deceleration of bidirectional feed. This effectively mitigates the rigid impact at the end of the stroke, reduces vibration, ensures accurate positioning of the heart-shaped mold column, and ensures smooth feed of the pressing device, improving the consistency and reliability of the pre-fitting action.

[0015] The crimping cylinder for the copper crimping tube is a driving cylinder for the crimping tube molding process. During the crimping process, the copper crimping tube undergoes plastic deformation, which inherently has a certain energy absorption and buffering effect, thus eliminating the need for additional throttling and speed-regulating components. The crimping cylinder branch relies on a solenoid valve, a pressure reducing valve, and a check valve assembly to achieve two-stage pressure control. During unloaded travel, the solenoid valve is energized and conducts, the pressure reducing valve engages, and the system switches to a preset low pressure to complete the pre-clamping operation. The cylinder quickly approaches the clamping tube, clamping it without causing plastic deformation. Subsequently, the PLC issues a command, the solenoid valve de-energizes and disconnects the circuit, the low-pressure limit is released, and the oil circuit switches to the rated secondary high pressure of the hydraulic pump system to complete the crimping operation. After crimping, the check valve assembly closes the oil chamber, working with the accumulator to supplement and maintain pressure, stabilizing the operating pressure and ensuring the quality of the crimped tube.

[0016] The push cylinder of the terminal crimping platform is responsible for tightening the suspension string during the pre-tensioning process. The other end of the suspension string is fixed to the hanging column driven by the servo motor. To avoid excessive hydraulic cylinder tension causing overload or damage to the servo motor, an independent pressure reducing valve is configured in its circuit. By reducing the working pressure of the hydraulic cylinder, the maximum tension force is limited, ensuring that the tensioning process is safe and controllable. Therefore, there is no need to set up additional throttling speed control components.

[0017] The terminal crimping cylinder is equipped with an electromagnetic reversing valve to realize the terminal crimping action. During the crimping process, the mold squeezes the copper wire terminal to cause plastic deformation, which has a certain energy absorption and buffering effect, so there is no need to set up additional throttling and speed regulating components.

[0018] Each branch circuit has a built-in hydraulic check valve forming a bidirectional locking circuit, which can suppress internal leakage of the cylinder and enable long-term pressure holding and self-locking at the tensioning and pressing positions. The six branches operate independently in parallel, and the actions of the positions do not interfere with each other, which can simultaneously adapt to various working conditions such as shearing, sliding, tensioning, and pressing.

[0019] The electrical control unit is based on a PLC and integrates a tension sensor, a slotted photoelectric switch, an oil temperature sensor, and drive and alarm modules. Through multi-sensor signal fusion, it achieves fully automatic control of photoelectric automatic wire release triggering, closed-loop tensioning, oil temperature linkage heat dissipation, servo precise positioning, time-sequential graded pressing, negative tolerance cutting, and error transfer. It also has over-temperature, over-pressure, and tension abnormality fault protection and alarm functions.

[0020] This invention also provides a hydraulic control method for an integral dropper prefabrication platform. This invention abandons the traditional molding process that accumulates errors and the purely manual fixed-value control mode. Its core adopts a high-precision intelligent molding strategy that utilizes single-sided limit positioning to determine the return line, negative tolerance cutting, servo rigidity to determine the main body size, and continuous tensioning to transmit errors. Combined with a mechatronics integrated intelligent control logic that includes manual-assisted alignment, tension closed-loop, adjustable graded hydraulic pressing, and oil temperature-linked pressure stabilization, this completely eliminates process accumulation errors and human error, achieving ultra-high precision standardized intelligent prefabrication of integral droppers for rail transit. The method includes the following steps: (1) The automatic wire feeding and tensioning cutting process adopts an electromechanical sensing closed-loop linkage control structure to realize the integrated operation of fully automatic wire feeding, precise tensioning and negative tolerance positioning cutting of the dropper. During operation, the pre-formed heart-shaped ring of the dropper on one side is hung on the hanging column; the PLC control system calculates the theoretical total length of the wire according to the standard length of the main dropper and the preset length of the return wire at both ends, drives the servo motor to move precisely along the linear guide rail, controls the hanging column to stop at the negative tolerance displacement position corresponding to the theoretical total length, and at the same time, the dropper wire moves synchronously by relying on the hanging column to pull the dropper wire. The wire is pulled and the sliding aluminum block is lifted, so that the slotted photoelectric switch is released from the block. Through the combination of mechanical triggering and photoelectric detection, the control signal is automatically output to start the wire winding motor and complete the uniform speed wire feeding.

[0021] Once the servo motor reaches the preset negative tolerance travel position, the system automatically switches the control logic, and the winding motor reverses to tension the dropper wire. A tension sensor detects tension in real-time online, forming a closed-loop tension control system. When the wire tension reaches the process-set threshold, the winding motor immediately stops and engages the brake, effectively ensuring uniform tension throughout the dropper wire. After tension locking, the shearing cylinder actuates, cutting the wire based on the servo negative tolerance positioning. This ensures the actual total wire length is less than the theoretically calculated length, reserving dimensional space for subsequent error directional transfer.

[0022] This solution deeply integrates multiple units such as servo negative tolerance positioning, photoelectric triggering, tension sensing, motor drive and hydraulic shearing, eliminating manual intervention and step-by-step operation mode, and realizing the full-process automation of wire laying, tensioning and negative tolerance positioning and cutting, which greatly improves positioning accuracy, tensioning stability and process continuity.

[0023] (2) Automatic length tensioning process of the main line. This process is the original high-precision control core of this invention. It combines mechanical limit, product size differentiation design and negative tolerance positioning and cutting process to realize the directional diversion of processing error. The specific steps are as follows: During operation, the pre-formed heart-shaped ring of the dropper wire on one side is hung on the hanging post. The other end of the dropper wire, after being cut, is then manually threaded through the crimping tube and the terminal head in sequence. The terminal head crimping cylinder is activated to complete the crimping of the terminal head and hold it in place. Then, the heart-shaped ring of the dropper wire is placed on the heart-shaped telescopic post, and the crimping tube crimping cylinder performs a first-stage low-pressure pre-compression, so that the crimping tube is initially clamped and does not produce plastic deformation, ensuring that the dropper wire can slide smoothly within the crimping tube.

[0024] The PLC control system drives the servo motor to move the hanging column, pulling the drop wire to the preset length position of the main drop wire. The servo mechanism completes the stroke and locks precisely. The distance between the hanging column and the heart-shaped telescopic column is the standard size of the main drop wire. Because the wire was cut with negative tolerance positioning in the early stage, the actual total length is less than the theoretical calculation value. After the main drop wire size is rigidly fixed, the length of the return wire on the other side is insufficient to the set reference distance. The push cylinder of the wire terminal crimping platform cannot contact the mechanical limit and always maintains a reverse traction state, which drives the drop wire to slide relatively in the crimping tube and complete the overall tensioning. All dimensional errors caused by cutting, assembly and wire deformation are transferred to the return wire area where no precision is required.

[0025] The system collects tension signals in real time through a tension sensor, forming a closed-loop tension control. When the tension reaches the process set value, the push cylinder of the terminal crimping platform stops moving and holds the pressure locked. Subsequently, the push cylinder of the crimping pipe platform continues to output thrust, and the crimping platform moves towards the heart-shaped column. When the crimping pipe slides to the set distance from the heart-shaped ring, it stops. Then, the crimping pipe cylinder performs a two-stage high-pressure boosting crimping, causing the crimping pipe to undergo permanent plastic deformation, achieving a firm interlocking connection. After all cylinders reset and the servo motor returns to its position, the overall dropper pre-assembly operation is completed.

[0026] This solution adopts a step-by-step process logic of low-pressure pre-clamping, servo rigid length setting, continuous tensioning to transfer errors, and finally high-pressure forming. It integrates multiple technologies such as servo precise positioning, hydraulic graded pressurization, tension sensing closed loop, mechanical limit and negative tolerance positioning and cutting to overcome the defects of insufficient precision and discrete tension in traditional processing methods. It can stably control the length error of the main suspension cable within ±0.5mm, resulting in high product consistency and strong structural connection.

[0027] (3) Oil temperature linkage and full-domain pressure stabilization and pressure holding control process: the oil temperature sensor monitors the hydraulic oil temperature in real time throughout the operation. When the temperature exceeds the limit, the return oil cooler is linked to force heat dissipation and alarm, ensuring the stability of hydraulic oil viscosity and system pressure. All tensioning, pressing and pressure holding stations are locked in both directions by hydraulic control check valves and dynamically replenished by accumulators, which completely suppresses internal leakage and pressure decay in the cylinder and ensures consistent pressure in batch production.

[0028] This invention addresses the prefabrication of integral droppers by providing a systematic technical solution from five dimensions: hydraulic circuit architecture, differentiated pressure regulation, long-term pressure-holding structure, error transfer process, and electromechanical-hydraulic control logic. This solution differs from existing conventional equipment. Combining the high-precision structure of the main dropper wire and the lack of precision requirements for the return wire, a single-sided current-carrying ring is referenced and sized using mechanical limiting. A servo mechanism controls the wire cutting with negative tolerances, artificially creating dimensional differences. Then, the servo mechanism rigidly locks the main dropper wire to a fixed length, and a hydraulic cylinder continuously tensions it, directionally transferring all accumulated errors from wire laying, cutting, tooling slippage, and wire elastic deformation to the current-carrying ring area where precision is not required. This process fundamentally solves the long-standing industry problem of error accumulation, steadily improving the dimensional accuracy of the main dropper wire.

[0029] It adopts an open hydraulic architecture with a common oil source and six independent parallel workstation execution branches. The six branches correspond to all working cylinders for shearing, telescopic, sliding and pressing. The actions and pressure control of each branch are completely independent, which completely solves the problems of workstation action interference and pressure coupling fluctuation caused by traditional single oil circuit sharing. It supports multi-process synchronous operation and effectively improves production efficiency.

[0030] Customized hydraulic control logic is provided for different operating conditions: the heart-shaped column and sliding cylinder branch are equipped with one-way throttle valves to achieve return oil throttling speed regulation and eliminate hard limit impact vibration; the sliding branch of the line terminal is equipped with an independent pressure reducing valve to achieve low pressure stabilization and tension limitation; the crimping branch of the crimping pipe integrates a two-stage adjustable pressure boosting and buffering control module, and adopts a low-pressure pre-clamping + high-pressure forming dual-stage switching process. The low-pressure and high-pressure parameters can be flexibly adjusted according to the wire diameter, material and process standards of the dropper wire, which is suitable for the production of precision dropper wires for multiple specifications of rail transit, and solves the industry problems of traditional single-stage crimping that easily damages the wire and is not tight.

[0031] Each workstation branch circuit has a built-in hydraulic control check valve forming a bidirectional locking circuit, which works in conjunction with the main oil circuit accumulator to provide real-time pressure replenishment and stabilization, while a return oil cooler ensures constant oil temperature control. This hydraulic structure suppresses internal leakage in the cylinders, ensuring no pressure drop or tooling loosening during long-term pressure-holding processes such as tensioning and pressing, and maintaining constant operating pressure throughout the entire process.

[0032] By integrating multi-dimensional signals such as servo positioning, photoelectric triggering, tension sensing, and oil temperature monitoring, an intelligent operation mode of "manual assisted material loading and alignment + PLC fully automatic timing control + tension closed-loop precise regulation + oil temperature linkage and pressure stabilization" is constructed. This mode abandons the traditional pure manual operation mode, completely eliminates human operation errors, and adapts to the standardization and large-scale intelligent mass production needs of precision components for rail transit.

[0033] The beneficial effects of this invention are as follows: 1. Error-oriented transfer ensures controllable precision of the main dropper. Considering the differentiated precision requirements of the overall dropper structure, mechanical limits are used to restrict the length of the return line on one side; servo-controlled negative tolerance positioning and cutting create dimensional differences, causing the return line length on the other side to be less than the standard value. The pressing platform's push cylinder continuously tensions the dropper, directionally transferring dimensional errors generated throughout the process to the return line section where precision requirements are not specified. The dimensional accuracy of the main dropper is stably maintained within ±0.5mm, resulting in high product consistency.

[0034] 2. Six independent parallel hydraulic circuits enable multi-station collaborative operation without interference. This completely solves the problems of pressure coupling and motion interference in traditional shared hydraulic circuits, allowing multiple processes to operate simultaneously and significantly improving mass production efficiency.

[0035] 3. Graded adjustable pressure crimping, wide adaptability and high forming quality. Low-pressure pre-clamping and high-pressure forming pressure can be flexibly adjusted to adapt to the processing of integral droppers with different wire diameters and materials. Low-pressure clamping is non-damaging and high-pressure forming is firm, eliminating problems such as loose connection, broken strands and weak crimping.

[0036] 4. The system features bidirectional locking, energy storage and pressure replenishment, and constant oil temperature, resulting in extremely high system stability. It resolves accuracy fluctuations caused by internal cylinder leakage, pressure decay, and oil temperature drift, making it suitable for long-term continuous mass production.

[0037] 5. Fully automated closed-loop intelligent control of electromechanical and hydraulic systems, minimizing human error. It abandons the manual experience-based control mode, employing intelligent linkage control of tension, pressure, and temperature throughout the entire time sequence. With a high degree of standardization and intelligence, it fully meets the precision dropper prefabrication standards for high-end intelligent equipment in rail transit. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the hydraulic system of the present invention; Figure 2 This is a schematic diagram illustrating the overall suspension cable tensioning principle of the present invention. Figure 3 This is a schematic diagram of the shear control principle of the suspension cable of the present invention.

[0039] Explanation of reference numerals in the attached figures: 1-Oil tank, 2-Air filter, 3-Level gauge, 4-Hydraulic pump, 5-Pressure gauge, 6-Unloading relief valve, 7-Suction filter, 8-Return oil cooler, 9-Accumulator, 10-Solenoid valve, 11-Pressure reducing valve, 12-Check valve assembly, 13-Double check valve, 14-Hydraulic check valve, 15-Independent pressure reducing valve, 16-Solenoid directional valve, 17-Shearing cylinder, 18-Heart-shaped column telescopic cylinder, 19-Crimping pipe crimping platform push cylinder, 20- 21-Crimping cylinder for crimping pipe, 22-Crimping platform cylinder for wire terminal head, 23-Crimping cylinder for wire terminal head, 24-Shearing cutter, 25-Suspension plate, 26-Heart-shaped telescopic column, 27-Heart-shaped ring, 28-Crimping pipe, 29-Wire terminal head, 30-Servo hanging column, 31-Tension sensor, 32-Servo motor, 33-Wire reel motor, 34-Wire reel, 35-Wire feeding bracket, 36-Sliding aluminum block, 37-Slotted photoelectric switch. Detailed Implementation

[0040] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0041] like Figure 1 As shown, a hydraulic control system for an integrated dropper prefabrication platform employs a single oil source with six independent parallel open circuits. The oil source is unified, and the valve groups and cylinders of the six workstation branches are independently controlled. A common unit achieves filtration, cooling, energy storage, and pressure stabilization. The electrical control unit integrates closed-loop timing control of multiple signals including servo, tension, photoelectric, and oil temperature signals, and is equipped with a unique error transfer prefabrication process. The specific system structure is as follows: Oil-powered power unit assembly: An air filter 2 and a level gauge 3 are installed on the top of the oil tank 1, and an oil suction filter 7 is connected in series at the bottom oil outlet to the hydraulic pump 4; the hydraulic pump's main oil outlet is connected in parallel with an unloading overflow valve 6 and a pressure gauge 5, and an accumulator 9 is connected in parallel at the end of the main oil circuit; the system's total return oil is connected to the return oil cooler 8 and then flows back to the oil tank, completing the construction of the common auxiliary protection unit.

[0042] The six workstation branch lines are arranged in parallel, with each branch line connected to the main pressure oil circuit at its beginning and the return oil collected at its end to the return oil cooler 8; valve groups are matched according to the function of each workstation. Heart-shaped column telescopic cylinder 18, crimping pipe crimping platform push cylinder 19, branch line is equipped with double one-way throttle valve 13 to realize bidirectional oil return throttling and deceleration; The crimping cylinder has 20 branches connected in series with solenoid valves 10, pressure reducing valves 11, and check valve group 12 to achieve switching between 0.5MPa low-pressure pre-clamping and 5.0MPa high-pressure forming. An independent pressure reducing valve 15 is added to the 21 branch of the terminal crimping platform push cylinder to limit the maximum tension force. All branches are equipped with solenoid directional valves 16 and hydraulic check valves 14, forming a bidirectional locking and pressure-maintaining circuit.

[0043] Electrical control wiring: The PLC is electrically connected to the servo motor 32, tension sensor 31, slotted photoelectric switch 37, oil temperature sensor, all electromagnetic reversing valves, solenoid valves, and audible and visual alarm modules respectively; the terminal crimping platform push cylinder 21 is equipped with mechanical limit blocks, and the reference spacing of 300mm is set as the standard length of the single-sided return line.

[0044] A hydraulic control method for an integral dropper pre-assembly platform, such as Figure 2-3 As shown, the specific steps are as follows: 1. Prefabrication of a single-sided return line: The dropper wire 24 is manually picked up and threaded through the crimping tube and the terminal block. The terminal crimping cylinder 22 is activated to tighten the terminal block. The system outputs a low pressure of 0.5MPa to clamp the crimping tube. The terminal crimping platform push cylinder 21 pulls the dropper wire 24 to slide on the crimping tube and finally abuts against the mechanical limit, locking the length of the return line on this side at 300mm. Subsequently, the crimping platform push cylinder continues to output thrust, and the crimping platform moves towards the heart-shaped column and stops after moving a set distance. The crimping tube is then crimped under high pressure, completing the prefabrication of one end of the return line.

[0045] 2. Automatic wire feeding and negative tolerance cutting: The heart-shaped ring 27 of the first prefabricated return wire is hung on the servo hanging column 30. The PLC calculates the theoretical total length of the wire based on the target body length and the total length of the return wires on both sides, and drives the servo motor 32 to pull the wire and lift the sliding aluminum block 36. When the obstruction is released, the slotted photoelectric switch 37 is triggered, and the wire reel motor 33 feeds the wire at a constant speed. The servo stops when it reaches the position of negative tolerance of the theoretical total length, the motor reverses to reel in the wire, and the tension sensor locks the tension in a closed loop. The shearing cylinder 17 extends to cut the wire, and the actual length of the wire is shorter than the theoretical value. 3. Low-pressure pre-clamping and sliding assembly: The free end of the cut wire is manually inserted into the crimping tube 28 and the wire terminal 29. The wire terminal crimping cylinder 22 is activated to clamp the terminal. The heart-shaped ring 27 is fitted onto the heart-shaped telescopic column 26. The solenoid valve 10 is energized, the pressure reducing valve 11 is connected to the circuit, and the system outputs 0.5MPa low-pressure clamping crimping tube, allowing the wire to slide without resistance. 4. Servo rigid fixed length + error-oriented tensioning: The PLC drives the servo motor to move to the standard length position of the main body suspension string and mechanically locks it. The distance between the servo hanging column 30 and the heart-shaped telescopic column 26 is the precise main body size. The push cylinder 21 of the wire terminal crimping platform continuously extends and tensions. Due to the negative tolerance of the wire cutting, the length of the return section on the other side is less than 300mm of the reference. The push cylinder 21 of the wire terminal crimping platform cannot contact the limit block. The continuous tension transfers all errors such as wire release gap, cutting error, tooling slippage, and wire elastic deformation to the other return line where there is no precision requirement. After the tension reaches the standard, the hydraulic control check valve of the push cylinder locks and maintains pressure. 5. High-pressure forming and crimping: When the solenoid valve 10 is de-energized, the low-pressure circuit is cut off, and the main system's 5.0MPa high pressure is introduced into the crimping cylinder 20, which squeezes the crimping tube 28 to produce permanent plastic deformation, ensuring that the wires are tightly interlocked without slippage; 6. Reset and discharge: After the pressure holding delay is completed, all solenoid directional valves are switched, each oil cylinder is retracted, the servo motor returns to the origin, and the finished hanging wire is manually removed, and the processing of a single piece is completed.

[0046] Implementation of coordinated control of oil temperature and pressure holding: During continuous processing, the oil temperature sensor collects the return oil temperature in real time, with a preset operating range of 30-50℃. When the oil temperature exceeds 50℃, the PLC activates the return oil cooler at full power for heat dissipation and triggers an alarm. When the temperature is below 30℃, the return oil cooler operates at low power to save energy. In all tensioning, pressing, and pressure holding processes, the branch hydraulic control check valve closes the two chambers of the cylinder to suppress internal leakage, and the accumulator 9 continuously replenishes pressure to the main oil circuit. The pressure fluctuation throughout the process is ≤0.05MPa, and there is no pressure decay during long-term pressure holding.

[0047] In this embodiment, the typical parameters are 300mm for the return line reference, 0.5MPa for the pre-clamping low pressure, and 5.0MPa for the forming high pressure. When processing copper stranded wires of different diameters, the high and low pressure settings, negative tolerance offset, tension threshold, and servo fixed length coordinates can be directly modified in the PLC human-machine interface. The system automatically adapts without the need to replace the hydraulic hardware valve group, and the equipment has strong versatility.

[0048] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A hydraulic control system for an integral dropper pre-assembly platform, characterized in that, This includes an oil-powered unit, a common auxiliary protection unit, multiple sets of modular workstation execution branches, and an electronic control unit; The system adopts an open parallel hydraulic circuit structure, with all modular workstation execution branches sharing a single oil source power unit. Each workstation execution branch is independent of the others, and the oil circuits do not interfere with each other. The oil source power unit is used to supply pressurized oil to the entire hydraulic circuit and realize system overload protection and hydraulic pump unloading; the common auxiliary protection unit integrates oil filtration, oil temperature regulation, and pressure stabilization and replenishment functions. Each modular workstation execution branch is equipped with a solenoid directional valve and a hydraulic check valve to form a two-way locking circuit; each workstation execution branch is configured with speed regulating elements and pressure regulating elements according to the different working conditions. The electronic control unit is connected to the execution branches of each workstation, external sensors and servo mechanism signals, and is configured with organic electro-hydraulic linkage control logic. It can combine mechanical limit, negative tolerance cutting and continuous tensioning to transfer the processing size error to the return line area where the suspension cable has no precision requirements.

2. The hydraulic control system for the integral dropper pre-assembly platform according to claim 1, characterized in that, The modular workstation execution branch is set into six groups, corresponding to the shearing cylinder, the heart-shaped column telescopic cylinder, the crimping pipe platform push cylinder, the crimping pipe crimping cylinder, the wire terminal crimping platform push cylinder, and the wire terminal crimping cylinder.

3. The hydraulic control system for the integral dropper pre-assembly platform according to claim 2, characterized in that, The heart-shaped column telescopic cylinder and the press pipe pressing platform push cylinder are equipped with double one-way throttle valves on the corresponding work station execution branch, and the return oil throttling speed regulation method is used to buffer the rigid impact at the end of the cylinder action.

4. The hydraulic control system for the integral dropper pre-assembly platform according to claim 2, characterized in that, The pressing cylinder of the pressing pipe is equipped with a solenoid valve, a pressure reducing valve and a check valve group on the corresponding work station execution branch, forming a two-stage pressure control circuit; when the solenoid valve is energized, it connects to the low-pressure circuit to realize pre-clamping, and when the solenoid valve is de-energized, it switches to the system high pressure to realize forming pressing. The low pressure and high pressure can be flexibly adjusted according to the working conditions.

5. The hydraulic control system for the integral dropper pre-assembly platform according to claim 2, characterized in that, The pressure reducing valve is independently configured on the work station execution branch corresponding to the push cylinder of the terminal crimping platform to limit the maximum output pulling force of the hydraulic cylinder.

6. The hydraulic control system for the integral dropper pre-assembly platform according to claim 5, characterized in that, The push cylinder of the terminal crimping platform is equipped with a mechanical limiting structure, which is used to limit the reference distance between the crimping terminal mold and the heart-shaped ring telescopic shaft.

7. The hydraulic control system for the integral dropper pre-assembly platform according to claim 1, characterized in that, The oil power unit includes an oil tank, an air filter, a level gauge, a hydraulic pump, a pressure gauge, and an unloading relief valve; the unloading relief valve is connected in parallel to the main oil line and has the functions of overflow pressure stabilization, overload protection, and hydraulic pump unloading.

8. The hydraulic control system for the integral dropper pre-assembly platform according to claim 1, characterized in that, The common auxiliary protection unit includes an oil suction filter, a return oil cooler, and an accumulator; the oil suction filter is connected in series at the hydraulic pump suction port, the return oil cooler is arranged in the system return oil pipeline, and the accumulator is connected in parallel to the main oil circuit to cooperate with the unloading relief valve to achieve pressure stabilization and dynamic pressure replenishment.

9. The hydraulic control system for the integral dropper pre-assembly platform according to claim 1, characterized in that, The electrical control unit includes a PLC controller, a tension sensor, a slotted photoelectric switch, an oil temperature sensor, and a drive alarm module; the tension sensor, the slotted photoelectric switch, and the oil temperature sensor are respectively electrically connected to the PLC controller.

10. A hydraulic control method for an integral dropper pre-assembly platform based on the system according to any one of claims 1-9, characterized in that, The operation mode adopts a combination of manual-assisted alignment and PLC fully automatic timing control, tension closed loop, photoelectric triggering, and oil temperature linkage, including automatic wire feeding, tensioning and cutting process, main wire fixed length tensioning and error compensation graded pressing process; In the automatic wire feeding, tensioning and cutting process, the servo hanging column is controlled to move to the negative tolerance position of the theoretical total length of the wire before the cutting is completed, so that the actual total length of the wire is less than the theoretically calculated total length. In the main line fixed-length tensioning and error compensation graded pressing process, the reference size of the single-sided return line is calibrated by mechanical limit, and the main suspension wire is rigidly fixed and locked by servo mechanism. With the continuous tensioning of the oil cylinder, the dimensional error caused by cutting, assembly and elastic deformation of the wire is transferred to the other return line area of ​​the suspension wire. At the same time, the hydraulic system adopts a graded pressing mode of low-pressure pre-clamping and high-pressure forming to complete the pressing operation.

11. The hydraulic control method for the integral dropper pre-assembly platform according to claim 10, characterized in that, The automatic wire feeding, tensioning, and cutting process specifically includes: S1: Pre-fabricate the return wire at one end of the drop wire according to the set standard length, and hang the pre-fabricated return wire heart-shaped ring on the servo hanging column. The PLC drives the servo motor to pull the wire to move. The wire triggers the slotted photoelectric switch and starts the wire reel motor to release the wire at a uniform speed. S2: The servo column stops after traveling to the negative tolerance displacement position corresponding to the theoretical total length. The wire reel motor reverses to wind up and tension the wire. The tension sensor collects the tension signal to form a closed-loop control. The wire reel motor stops and locks when the tension reaches the set threshold. S3: The PLC controls the shearing cylinder to complete the wire cutting.

12. The hydraulic control method for the integral dropper pre-assembly platform according to claim 10, characterized in that, The mainline fixed-length tensioning and error compensation graded pressing process specifically includes: (1) The first prefabricated return wire heart-shaped ring is still hung on the servo hanging column. One end of the cut wire is inserted into the crimping tube and the wire terminal head. The wire terminal head is crimped and pressure is maintained. The heart-shaped ring is then assembled onto the heart-shaped column. (2) The hydraulic circuit is switched to low-pressure mode to pre-clamp the crimping tube under low pressure, so that the wire can slide freely in the crimping tube; (3) The PLC automatically calculates the standard length of the main suspension cable according to the preset parameters, drives the servo motor to move the hanging column to the corresponding position and mechanically locks it, thus completing the rigid fixed length of the main suspension cable; (4) The push cylinder of the terminal crimping platform continuously outputs traction force to transfer the dimensional error to the return line area on the other side. After the tension reaches the standard, the push cylinder holds pressure and locks the position. (5) The pressing platform push cylinder continuously outputs thrust, and the pressing platform moves towards the heart-shaped column. It stops when the pressing pipe slides to a set distance from the heart-shaped ring. (5) The hydraulic circuit is switched to high pressure mode to complete the high pressure forming and pressing of the press tube; (6) All cylinders and servo mechanisms are reset to complete the pre-assembly of a single dropper.

13. The hydraulic control method for the integral dropper pre-assembly platform according to claim 10, characterized in that, During operation, the oil temperature sensor monitors the hydraulic oil temperature in real time. When the oil temperature exceeds the set range, the PLC activates the alarm module and links the return oil cooler to enhance heat dissipation. During the system pressure holding phase, the main oil circuit accumulator works with the hydraulic control check valves of each branch to replenish pressure in real time and suppress pressure decay.

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