Cold pilger mill

Abstract

The utility model discloses a cold pilger mill, which relates to the technical field of cold pilger mills, aims to solve the problem of product precision, and comprises execution hardware used for processing pipe fittings, a hydraulic loop used for driving the execution hardware and a control system used for outputting command signals, the execution hardware comprises a main body, a roller and a hydraulic cylinder, the hydraulic cylinder and the roller are arranged on the main body, the roller is connected with the pressure output end of the hydraulic cylinder, and the hydraulic loop comprises an oil tank, an oil pump and a reversing valve. According to the scheme, a hydraulic loop and a control system are matched for optimization, the load-sensitive pump and the electro-hydraulic proportional reversing valve are combined for application, the flow and pressure of hydraulic oil can be accurately adjusted according to the real-time requirement of the rolling working condition, and compared with a traditional constant displacement pump system, the energy utilization rate is increased by 30% or above.

Description

Technical Field

[0001] This utility model relates to the technical field of cold rolling mills, specifically a cold rolling mill. Background Technology

[0002] In the field of seamless steel pipe processing, cold rolling mills are the core equipment for achieving high-precision and high-efficiency pipe forming. Traditional cold rolling mills mainly consist of mechanical actuators, conventional hydraulic systems, and simple control systems, and have gradually revealed many undeniable technical shortcomings during long-term application.

[0003] From the perspective of hardware implementation, the hydraulic cylinder's power output stability is insufficient, and it is prone to impact loads during frequent start-stop processes, which not only affects the surface quality of the pipe but also significantly shortens the service life of the hydraulic cylinder.

[0004] In terms of hydraulic circuits, traditional systems mostly use fixed displacement pumps or ordinary variable displacement pumps, which cannot accurately adjust flow and pressure according to the real-time requirements of rolling conditions, resulting in a large amount of energy waste. At the same time, the directional valves are mostly ordinary electromagnetic directional valves, which have slow switching response speed and low precision, making it difficult to achieve precise synchronous control of roll movement; the circuit lacks effective pressure compensation and energy recovery devices, which can easily cause pressure shocks during sudden load changes, leading to damage to hydraulic components and increasing equipment maintenance costs and downtime.

[0005] In the field of control systems, traditional cold rolling mills mostly use control logic based on ordinary PID algorithms. PID parameters are mostly fixed values, making it difficult to adapt to complex working conditions such as changes in tube material and fluctuations in rolling force during the rolling process. Furthermore, the signal acquisition and feedback mechanisms are imperfect, making it impossible to monitor the equipment's operating status in real time and comprehensively. When a fault occurs, it is difficult to provide timely warnings and pinpoint the cause, further reducing production efficiency and equipment operational safety. Utility Model Content

[0006] To address the aforementioned problems, i.e., the issues raised in the background art, this utility model proposes a cold rolling mill for processing tubes, comprising execution hardware for processing tubes, a hydraulic circuit for driving the execution hardware, and a control system for outputting command signals. The execution hardware includes a main body, rolls, and a hydraulic cylinder. Both the hydraulic cylinder and the rolls are mounted on the main body. The rolls are connected to the pressure output end of the hydraulic cylinder. The hydraulic circuit includes an oil tank, an oil pump, and a directional valve. The oil pump is a load-sensitive pump, and the directional valve is an electro-hydraulic proportional directional valve. The oil intake port of the load-sensitive pump is connected to the oil tank via a hydraulic pipeline. The system is interconnected, with the output end of the load-sensitive pump connected to the P port of the electro-hydraulic proportional directional valve, the sensitive chamber of the load-sensitive pump connected to the LS port of the electro-hydraulic proportional directional valve via a feedback pipe, the A and B ports of the electro-hydraulic proportional directional valve connected to the rod-side and rodless-side chambers of the hydraulic cylinder respectively, and the T port of the electro-hydraulic proportional directional valve having a return pipe to the oil tank; an accumulator and a throttle valve connected in parallel are provided between the electro-hydraulic proportional directional valve and the hydraulic cylinder connection circuit, with the accumulator located near the hydraulic cylinder; and a pressure compensation valve is connected in series in the hydraulic circuit between the load-sensitive pump and the electro-hydraulic proportional directional valve.

[0007] A further feature of this invention is that an oil suction filter is provided at the oil inlet of the load-sensitive pump, and a return oil filter is provided at the T-port of the electro-hydraulic proportional directional valve.

[0008] A further feature of this invention is that the control system includes a signal input unit for staff to input parameters, a controller unit for logic control, a reversing valve drive unit for amplifying signals, and a feedback detection unit for monitoring equipment operating data. The controller unit is a programmable logic controller (PLC), the reversing valve drive unit is a power amplifier circuit, and the feedback detection unit includes, but is not limited to, a temperature sensor, a pressure sensor, a position sensor, and a vibration sensor.

[0009] The beneficial technical effects of this utility model are as follows: This solution optimizes the hydraulic circuit and control system, and the combined application of a load-sensitive pump and an electro-hydraulic proportional directional valve allows for precise adjustment of the hydraulic oil flow and pressure according to the real-time requirements of the rolling process. Compared with traditional fixed displacement pump systems, energy utilization is improved by more than 30%. The addition of a pressure compensation valve effectively balances the circuit pressure, avoiding pressure shocks during sudden load changes, and reducing the failure rate of hydraulic components by 50%. The accumulator can recover and store hydraulic energy during braking and reversing processes, and release it when needed, further reducing energy consumption. The precise adjustment function of the throttle valve enables stepless speed regulation of the roll feed speed, meeting the differentiated speed requirements of different rolling processes. The control system, combined with the control logic of the fuzzy PID algorithm, can quickly make adaptive adjustments based on the real-time feedback from the feedback detection unit. Attached Figure Description

[0010] Figure 1 A schematic diagram of the hydraulic circuit of this scheme is shown.

[0011] Figure 2 A schematic diagram of the control system is shown.

[0012] In the diagram: 1. Oil tank, 2. Suction filter, 3. Load-sensitive pump, 4. Pressure compensation valve, 5. Electro-hydraulic proportional directional valve, 6. Accumulator, 7. Throttle valve, 8. Hydraulic cylinder, 9. Return filter. Detailed Implementation

[0013] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0014] This utility model proposes a cold rolling mill. The existing rolling mill consists of three parts: execution hardware, hydraulic circuit and control system. The execution hardware consists of various execution mechanisms on the rolling equipment for rolling tubes, including a main body, rolls and hydraulic cylinder 8. The main body is used to control the speed and horizontal deflection angle of the rolls. The rolls are installed on the pressure output end of the hydraulic cylinder 8. The hydraulic cylinder 8 is installed on the main frame and is used to output pressure through the rolls.

[0015] The hydraulic circuit consists of an oil tank 1, an oil pump, and a directional valve. The oil pump draws hydraulic oil from the oil tank 1 and connects it to the rod chamber and rodless chamber of the hydraulic cylinder 8 through two outlets, thereby controlling the pressure of the rolls. The return port of the directional valve is connected to the oil tank 1, so that the returning hydraulic oil flows back into the oil tank 1.

[0016] The control system consists of a signal input unit for operators to input parameters, a controller unit for logic control, and a directional valve drive unit for signal amplification. The controller unit outputs control signals to control the directional valves and oil pumps in the execution hardware and hydraulic circuit.

[0017] In this design, the hydraulic circuit uses a load-sensitive pump 3 that automatically adjusts its output flow according to real-time system requirements. An electro-hydraulic proportional directional valve 5 is used to precisely control the flow direction and flow rate of the hydraulic oil, thereby achieving precise control of the roll movement. The P port (inlet) of the electro-hydraulic proportional directional valve 5 is connected to the output end of the load-sensitive pump 3. The sensitive chamber of the load-sensitive pump 3 is connected to the LS port (load-sensitive port) of the electro-hydraulic proportional directional valve 5 via a feedback pipe. Ports A (working port) and B (working port) are connected to the rod-side and rodless-side chambers of the hydraulic cylinder 8, respectively. A pipe is installed at the T port (return port) to return the oil to the oil tank 1. A pressure compensation valve 4 is connected in series between the load-sensitive pump 3 and the electro-hydraulic proportional directional valve 5 to adjust the pressure according to changes in load pressure. The opening size is automatically adjusted to automatically adjust the pressure according to the load change, ensuring that the flow through the electro-hydraulic proportional directional valve 5 is basically unaffected by the load change, and ensuring that the roll can obtain stable pressure under different working conditions. An accumulator 6 is set between the electro-hydraulic proportional directional valve 5 and the hydraulic cylinder 8, and close to the hydraulic cylinder 8. When the hydraulic cylinder 8 returns, the excess hydraulic energy is stored in the accumulator 6. When rapid feeding is required, the accumulator 6 releases the stored energy to assist the hydraulic pump in providing power to the system, thereby reducing the power demand of the hydraulic pump and achieving the purpose of energy saving. A throttle valve 7 is connected in parallel at the accumulator 6 to absorb hydraulic shock and reduce vibration when the roll reverses or stops, so as to avoid the roll being subjected to large pressure fluctuations that affect the accuracy.

[0018] An oil suction filter 2 is installed at the oil suction end of the load-sensitive pump 3, and a return oil filter 9 is installed at the oil return end of the electro-hydraulic proportional directional valve 5. These are used to remove impurities and wear particles from the hydraulic oil, ensure the cleanliness of the oil, and extend the service life of the hydraulic components.

[0019] In the control system, the controller unit uses a programmable logic controller (PLC) to receive instructions and parameter signals from the signal input unit, and also receives feedback signals such as actual pressure and position from the feedback detection unit. By comparing and calculating with preset parameters, the controller outputs control signals to the electro-hydraulic proportional directional valve 5 drive unit according to the control program. For example, when the actual roll pressure is less than the preset pressure, the controller outputs a control signal to increase the opening of the electro-hydraulic proportional directional valve 5. The directional valve drive unit uses a power amplifier circuit to amplify the weak control signal output by the controller unit, giving it sufficient energy to drive the electro-hydraulic proportional directional valve 5. The feedback detection unit consists of a temperature sensor, a pressure sensor, a position sensor, and a vibration sensor. The temperature sensor monitors the temperature of the hydraulic oil; the vibration sensor detects the vibration of the hydraulic cylinder 8 and the roll; the pressure sensor is installed near the hydraulic cylinder 8 or the roll to monitor the actual pressure of the roll in real time; and the position sensor monitors the roll's position information to determine the displacement. The information from these sensors is fused and processed to comprehensively judge the system's operating status and adjust the control strategy accordingly. When the hydraulic oil temperature is too high, reduce the rolling speed appropriately to avoid affecting the control accuracy due to changes in oil viscosity; when the vibration is too large, adjust the roll pressure in time to prevent equipment damage.

[0020] The control system employs a fuzzy PID algorithm. The classic PID algorithm calculates the control quantity based on the deviation between the setpoint (given parameter) and the actual output value (feedback parameter) through a linear combination of proportional, integral, and derivative components, thereby achieving precise control of the controlled object. The equation is u(t) = Kpe(t) + Ki∫e(t)dt + Kd(de(t)) / dt, where u(t) is the controller's output signal; e(t) is the deviation signal; and e(t) = r(t) - y(t), where r(t) is the deviation signal. The setpoint is y(t), which is the actual output value. Kp, Ki, and Kd are the proportional, integral, and derivative coefficients, respectively. Fuzzy PID introduces a fuzzy inference mechanism to dynamically adjust the three parameters in real time to adapt to nonlinear disturbances such as sudden load changes, oil temperature drift, and mechanical wear during rolling. This significantly improves the system response speed and steady-state accuracy. By identifying the rolling force change rate and oil temperature gradient online, when the deviation is large, Kp is increased to improve the system response speed; when the deviation is small, Kp is decreased and Ki is appropriately increased to eliminate steady-state error.

[0021] Compared to traditional PID control parameters, which are often fixed or adjusted manually based on experience, this solution uses a feedback detection unit to monitor factors such as pressure, temperature, position, and vibration in real time. The control system optimizes the control parameters in real time and performs precise regulation through an improved hydraulic circuit, ensuring product quality in all aspects.

[0022] Although the present invention has been described with reference to preferred embodiments, various modifications can be made to it and components can be replaced with equivalents without departing from the scope of the present invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

[0023] In the description of this utility model, terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," which indicate direction or positional relationships, are based on the direction or positional relationships shown in the accompanying drawings. These are used merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] Furthermore, it should be noted that, in the description of this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0025] The term "comprising" or any other similar term is intended to cover non-exclusive inclusion, such that a process, article, or apparatus / device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to those processes, articles, or apparatus / devices.

[0026] The technical solution of this utility model has been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the protection scope of this utility model is obviously not limited to these specific embodiments. Without departing from the principle of this utility model, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of this utility model.

Claims

1. A cold rolling mill for tubes, comprising execution hardware for processing tubes, a hydraulic circuit for driving the execution hardware, and a control system for outputting command signals, wherein the execution hardware comprises a main body, rolls, and a hydraulic cylinder (8), wherein the hydraulic cylinder (8) and the rolls are both mounted on the main body, and the rolls are connected to the pressure output end of the hydraulic cylinder (8), characterized in that: The hydraulic circuit includes an oil tank (1), an oil pump and a directional valve. The oil pump is a load-sensitive pump (3), and the directional valve is an electro-hydraulic proportional directional valve (5). The oil inlet of the load-sensitive pump (3) is connected to the inside of the oil tank (1) through a hydraulic pipeline. The output end of the load-sensitive pump (3) is connected to the P port of the electro-hydraulic proportional directional valve (5). The sensitive chamber of the load-sensitive pump (3) is connected to the LS port of the electro-hydraulic proportional directional valve (5) through a feedback pipeline. The A port and B port of the electro-hydraulic proportional directional valve (5) are connected to the rod chamber and rodless chamber of the hydraulic cylinder (8) respectively. The T port of the electro-hydraulic proportional directional valve (5) is provided with a pipeline for return flow to the oil tank (1). An accumulator (6) and a throttle valve (7) are connected in parallel between the electro-hydraulic proportional directional valve (5) and the hydraulic cylinder (8) circuit. The accumulator (6) is located near the hydraulic cylinder (8). A pressure compensation valve (4) is connected in series in the hydraulic circuit between the load-sensitive pump (3) and the electro-hydraulic proportional directional valve (5).

2. A cold pilger mill according to claim 1, characterized in that: The oil suction filter (2) is provided at the oil suction port of the load-sensitive pump (3), and the return oil filter (9) is provided at the T port of the electro-hydraulic proportional directional valve (5).

3. A cold pilger mill according to claim 1, characterized in that: The control system includes a signal input unit for operators to input parameters, a controller unit for logic control, a reversing valve drive unit for amplifying signals, and a feedback detection unit for monitoring equipment operating data. The controller unit is a programmable logic controller (PLC), the reversing valve drive unit is a power amplifier circuit, and the feedback detection unit includes, but is not limited to, temperature sensors, pressure sensors, position sensors, and vibration sensors.

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