The work roll is one of the most important components of the plate rolling machine, and its quality and performance directly affect the service life and rolling accuracy of the PR4 steel plate rolling machine.
The upper work roll is made of high-strength alloy steel 42CrMo and is forged (forging ratio 4:1). After rough machining, it is quenched and tempered to the effect of HB260~300. After finishing, the surface induction hardening hardness reaches about HRC52. Quenching and tempering, quenching, tempering, precision lathe, and grinding machine processing, and other processes are completed (note: according to the different needs of users, the processing technology of the roller is different); according to the JB/ZG4289-86 roll steel standard, the rigidity meets (1 /700~1/1000)L (L—refers to the distance between the centerlines of the racks on both sides). Strictly ensure that the surface contact strength of the work roll is high and that there is no indentation on the surface of the roll when rolling the steel plate, which can meet the requirements of long-term rolling of the steel plate. surface velocity. Each hydraulic motor is equipped with an instant brake to make the roller stop accurately at the set position under working conditions.
An encoder is installed at the rear of the hydraulic motor to detect the displacement of the steel plate rolling, so as to better control the relationship between the displacement of the plate and the up and down displacement of the oil cylinder, so as to realize fully automatic coiling.
Work roll movement
According to the movement mode of the working roll (lower roll and side roll) of the plate rolling machine, advanced linear slideway technology is adopted.
Both ends of each roller adopt high-precision self-aligning roller bearings, which can well offset the pressure caused by the shaft deviation during the rotation of the roller shaft.
Due to the free and flexible movement of each axis, the risk of scratches and cracks on the rollers is avoided. The internal design of this adjustable bearing allows it to accommodate roll misalignment and tilt. This collapsible movement avoids damage to the roller shaft due to opposing forces when it bears the force of the fixed housing.
Auxiliary drive mechanism
- Proportional servo valve: After the proportional valve receives the PLC command, it adjusts the oil supply to the hydraulic oil cylinders at each end of each work roll, so that the work roll can quickly reach the specified position and realize the parallelism of each roll.
- PLC: According to the signal sent by the displacement sensor, PLC judges the position of the work roll, and gives instructions to the proportional valve.
- Motion detector: The displacement sensor monitors the position of both ends of the work roll and outputs the signal to the PLC
The lifting of the lower roll and the rolls on both sides, the dumping and reset of the inverted head are all hydraulically driven, and the speed is slow when there is a load, and it can be raised and lowered quickly when there is no load or light load, so as to improve production efficiency. Both ends of the lower roller and the side roller can be raised and lowered at the same time, or separately.
The leveling accuracy of both ends of the lower roll and side rolls directly determines the speed and quality of the coiling. In order to better and more conveniently control the leveling accuracy of both ends of the lower roll and side rolls, the leveling accuracy is ±0.1mm The bending rollers are all controlled by proportional valves.