With the rapid development of the automobile industry, the demand for automobile tires is also increasing rapidly. At the same time, due to the rapid development of high-grade highways, the running speed of automobiles has also been greatly improved, which puts forward higher requirements for the quality of automobile tires. As an important part of the tire, the steel connecting wire plays an important role in the strength of the tire. The quality of the steel connecting line directly affects the quality, quality and grade of the tire. As the main production equipment of the steel connecting line, the direct wire drawing machine is more and more widely used. The early straight wire drawing machines were mainly imported, including those imported from Germany, Italy, South Korea and other places. These systems have DC speed regulation and AC frequency conversion speed regulation. Now these devices are still used in some large steel production plants.
Brief introduction to the working principle of straight wire drawing machine
The straight wire drawing machine is a small continuous production equipment composed of multiple drawing heads. Through step-by-step drawing, the steel wire can be cold-drawn to the required specifications at one time, so the working efficiency is relatively high. However, since the diameter of the steel wire changes after each level of drawing, the working line speed of each drawing head should also change.
Depending on the configuration of the drawing die, the drawing speed of each drawing head also changes. The benchmark of the drawing speed is that the second flow volume of the steel wire passing through the drawing die at each moment is constant, even if the following formula is established:
πr2×v1= πr2×v2
r: the diameter of the incoming steel wire
v1: the linear speed of the incoming steel wire
r: Diameter of outgoing steel wire
v2: the line speed of the outgoing steel wire
The working speed of each drawing head of the straight wire drawing machine is based on the above formula to ensure that each drawing head runs synchronously. However, the above description is based on the ideal steady-state working process. Due to the error of the mechanical transmission and the clearance of the mechanical transmission, as well as the dynamic working process of starting, accelerating, decelerating, and stopping, each pulling head cannot maintain Synchronization, therefore, most of the straight wire drawing machines now have tension sensors, which dynamically measure the tension of the steel wires between each drawing head, and then convert the tension into a standard signal (0~20mA or 0~10V), using this standard The signal is fed back to the speed-adjusting frequency converter, and the frequency converter uses this signal for closed-loop PID process control, and superimposes the adjustment amount calculated by PID on the main speed to keep the tension at each tension detection point constant, which also ensures that the straight wire drawing machine works at Synchronous working state of constant tension.
According to the above description, the straight wire drawing machine puts forward higher requirements on the performance of the frequency converter. The inverter should have the following performance:
1. Large starting torque at low frequency, strong overload capacity and high speed accuracy.
2. There is a built-in PID function, and the parameters of PID are rich.
3. Fast dynamic response.
With the rapid development of the automobile industry, the demand for automobile tires is also increasing rapidly. At the same time, due to the rapid development of high-grade highways, the running speed of automobiles has also been greatly improved, which puts forward higher requirements for the quality of automobile tires. As an important part of the tire, the steel connecting wire plays an important role in the strength of the tire. The quality of the steel connecting line directly affects the quality, quality and grade of the tire. As the main production equipment of the steel connecting line, the direct wire drawing machine is more and more widely used. The early straight wire drawing machines were mainly imported, including those imported from Germany, Italy, South Korea and other places. These systems have DC speed regulation and AC frequency conversion speed regulation. Now these devices are still used in some large steel production plants.
Brief introduction to the working principle of straight wire drawing machine
The straight wire drawing machine is a small continuous production equipment composed of multiple drawing heads. Through step-by-step drawing, the steel wire can be cold-drawn to the required specifications at one time, so the working efficiency is relatively high. However, since the diameter of the steel wire changes after each level of drawing, the working line speed of each drawing head should also change.
Depending on the configuration of the drawing die, the drawing speed of each drawing head also changes. The benchmark of the drawing speed is that the second flow volume of the steel wire passing through the drawing die at each moment is constant, even if the following formula is established:
πr2×v1= πr2×v2
r: the diameter of the incoming steel wire
v1: the linear speed of the incoming steel wire
r: Diameter of outgoing steel wire
v2: the line speed of the outgoing steel wire
The working speed of each drawing head of the straight wire drawing machine is based on the above formula to ensure that each drawing head runs synchronously. However, the above description is based on the ideal steady-state working process. Due to the error of the mechanical transmission and the clearance of the mechanical transmission, as well as the dynamic working process of starting, accelerating, decelerating, and stopping, each pulling head cannot maintain Synchronization, therefore, most of the straight wire drawing machines now have tension sensors, which dynamically measure the tension of the steel wires between each drawing head, and then convert the tension into a standard signal (0~20mA or 0~10V), using this standard The signal is fed back to the speed-adjusting frequency converter, and the frequency converter uses this signal for closed-loop PID process control, and superimposes the adjustment amount calculated by PID on the main speed to keep the tension at each tension detection point constant, which also ensures that the straight wire drawing machine works at Synchronous working state of constant tension.
According to the above description, the straight wire drawing machine puts forward higher requirements on the performance of the frequency converter. The inverter should have the following performance:
1. Large starting torque at low frequency, strong overload capacity and high speed accuracy.
2. There is a built-in PID function, and the parameters of PID are rich.
3. Fast dynamic response.
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