Dapeng Town Industrial Park, Tongshan District, Xuzhou City, Jiangsu Province, China
In most of the processing plants of industrial equipment for space frame fittings, when assembling for unique positions, there are strict operation guidelines for screwing, and there are often established standards for how much torque to release. After the screws are tightened, in order to avoid loosening, an additional pre-tightening force should be released. Therefore, the pre-tightening force will be cleared after half a turn. The space frame accessory screws are in ductile deformation after tightening, especially at high temperatures and Under the condition of vibration load, the continuous working pressure for a long time will cause the stress to loosen. After the screw becomes plastic deformation, its compressive strength will be greatly reduced or even invalid.
Torque control method defines: when the tightening torque exceeds a certain set operating torque, the tightening control measures are immediately terminated.
Advantages: The automatic control system is simple and immediate, and it is convenient to use torque or high-precision torque wrenches to check the quality of tightening.
Disadvantages: The control accuracy is not high (pre-tightening force deviation ± 25%), and the development potential of raw materials cannot be used flexibly.
bolted-ball space frame
The torque-angle control method is defined: firstly, after the anchor bolt is screwed to a small torque, and then just start, screw a required rotation angle control measure.
Advantages: The accuracy of the radial pre-tightening force of the anchor bolts of the space frame accessories is high (±15%), and it can receive a large radial pre-tightening force, and the marked values can be concentrated around the average value.
Disadvantages: The automatic control system is complicated, and it is necessary to accurately measure the two main parameters of torque and rotation angle, and it is not easy for the quality inspection unit to find an appropriate way to inspect the tightening results.
Advantages: The tightening accuracy is very high, and the pre-tightening force deviation can be manipulated within ±8%, but the key to its accuracy lies in the tensile strength of the anchor bolt itself.
Disadvantages: The whole process of tightening the space frame fittings requires dynamic and continuous measurement and discrimination of the slope of the torque and rotation angle curve. The practicability of the automatic control system and the calculation rate often have higher regulations.
