Bolted conduit as an installation requirement
The purpose of the bolting task is the application of a defined preload holding force) or the execution of certain adjustment or disassembly processes.
Application of a defined preload force
The most important application case in the bolting assembly is the determination of a defined preload force. The preload force must be determined in such a way that, on the one hand, theintended function remains a factand, on the other hand,the permissible load of the bolt connection.
The most common problems are the settling conditions of a joint and other assembly-related fluctuations in the achieved preload force.
Images of tension
The standard screw assembly does not allow effective determination of the required preload force.
Therefore, as an alternative,indirect measurementsshould be used to control the assembly process. Generally it is the tightening torque of the bolt assembly. The required tightening torque can be calculated from the preload force using the formula VDI 2230.
In addition,other parameterssuch as angle, bolting time, friction, etc., can be determined experimentally and serve as guide dimensions for the assembly process. The reference values provide us with tables as shown below.
Basically, by usinglength measurement, an additional indirect measurement value can be used to determine the preload force. However, these processes are very complicated and thereforenot very useful in practice.
The use of torque to determine measurement dimensions remains the best option due to its practical feasibility.
Table values for preload force and tightening torque
Performance of adjustment and disassembly procedures
In these cases, the processing dimensions described are a length measurement (depth of screwing or screwing) or an angle measurement (number of rotations). These dimensions can be recorded directly via a suitable measuring system or indirectly over time.
Example: Assembly of terminal connectors
The clamping screw is first tightened to a predefined torque and then unscrewed to a certain angle to allow easier connection of a cable.
Additional information:
