The pinch roll device is used to help the wire head rolled out by the finishing mill to enter the laying head to form a loop and to prevent the high-speed running wire tail from coming out of the rolling mill to accelerate the stacking steel due to the disengagement.
Pinch roll is the horizontal cantilever structure. It has a double roll device and one air cylinder which is used to control roll up and down synchronous clamp. Pinch roll is arranged before the entrance of wire discharger, respectively according to to the technical requirement of wire rod head, tail or full clamp clamping workpiece and turn it into the wire discharge machine.
The Function of Pinch Roll
The pinch roll is placed at the entrance of the coiler. Its main functions are:
1. Introduce the strip head into the coil guide inlet guide;
2. When the strip steel tail is thrown out from the wire rod block mill, the required tension is applied to the strip to obtain a good take-up shape;
3. A good roll shape is obtained by adjusting the level of the pinch rolls.
● Feeding specification: 5.5 ~ 16mm
● Feeding rate: 25~75m/s
● Pinch roll specification: φ183 × 72mm
● Max gripping force: 350N
● Maximum line velocity: 90m/s
● Speed increasing ratio: 6.92
● Electro motor model: DC Z4-180-41(DC Z4-180-41)
● Motor power: 55kW
● Motor speed:1500/3000 r/min
Pinch Roll Structure
The pinch roll is composed of an upper roll, lower roller, an upper roller opening, and closing device, a roll gap adjusting device, and a pinch roller transmission device. In order to improve the biting condition and to bend the strip head downward, the pinch roll is a pair of upper and lower roll, and the upper and lower rolls have an off angle of 10° to 20°. After the strip head enters the pinch roll, the head was forced to bend down and enter the coiler inlet guide.
Both the upper and lower rolls of the pinch roll have convexity, which is advantageous for centering and extending the life of the roll when the tape is taken up. The tension applied by the pinch rolls to the strip is determined by the pinch force of the pinch rolls and the drive motor. As the rolling speed increases, the strip thickness increases and the material strength increases. The lower pinch rolls are subjected to a large pressure, and a solid forged steel roll is often used.
In order to improve the wear resistance, the roll faces are all welded with a hard alloy. The upper roll is mounted on the oscillating roller frame and is controlled by the cylinder to open and close. The pressure of the cylinder must be determined according to the pressing force of the pinch roll. After the upper roll is pressed, the roll gap value to be left between the upper and lower rolls is related to the rigidity of the strip and the pinch roll system, and the general election is about 0.4 mm smaller than the strip thickness.
Therefore, the pinch roll must be provided with a roll gap adjusting device to limit the pressing position of the swinging roll frame to achieve roll gap adjustment; at the same time, adjust the parallelism of the roll body to facilitate the improvement of the winding quality. Common roll gap adjustment mechanisms include screw jack type and eccentric shaft type.