How to calculate the nut preload
According to material and effective diameter (area)
if the material of the bolt is Q235 and the effective diameter is 10.3mm, the maximum bearing force of the bolt is 210 × three point one four × 3 / 2) ^ 2
cylindrical threaded fastener with nut. A kind of fastener composed of head and screw (cylinder with external thread), which is used to connect two parts with through hole. This kind of connection is called bolt connection. If the nut is unscrewed from the bolt, the two parts can be separated, so the bolt connection is a detachable connection
extended data:
according to the manufacturing accuracy, ordinary bolts can be divided into three grades: A, B and C. grade A and B are refined bolts and grade C are rough bolts. For connecting bolts used in steel structure, unless otherwise specified, they are generally common rough C-grade bolts. The processing methods of different levels are different
based on the interaction between magnetic flux leakage field and magnetic powder at the defect of bolt, aiming at the difference between magnetic permeability of possible defects (such as cracks, slag inclusion, mixture, etc.) and steel permeability, the magnetic field at the discontinuity of these materials will change after magnetization, forming a partial magnetic flux leakage field on the workpiece surface
Hello, how to calculate the torque value of nut and bolt
The calculation formula is: tightening torque = torque coefficient × Preload × Nominal diameter of threadthe key is the torque coefficient. With the same thread specification, the torque coefficient of different surface treatment is different, and some even differ by one time. Therefore, it is not appropriate to calculate the torque according to 0.12 in some manuals or standards. The torque coefficient shall be obtained by test. The torque value of bolt is shown in the figure below. Hope to be able to help you, thank you
bus line: No. 137, about 8.3km in the whole journey
1. Walk 820m from Cheng east station to the North inner station of the fifth section of East Third Ring Road
2. Take No. 137, pass 12 stops, and reach the East Inner station of Liuli interchange of Third Ring Road
3. Walk about 1.2km to the east city passenger transport center
1. When there is less chance of bearing the maximum axial load Fmax on the ball screw pair and a little axial clearance is allowed, the preload is calculated according to 1 / 3 of the maximum axial load, that is, fprfmax / 3; 3. When the maximum axial load Fmax is difficult or impossible to calculate, it can be approximately taken as 1 / 20 ~ 1 / 10 of the axial rated dynamic load Ca, that is, fpr = (1 / 20 ~ 1 / 10) ca.
the preload cannot be directly measured, but indirectly measured according to the preload torque. There is a special dynamic preload torque measuring instrument for ball screw pairs, After measuring the pretightening torque with a measuring instrument, the pretightening torque can be obtained by dividing the pretightening torque value by the force arm. Generally, the pretightening force is not a fixed value, but also a range. The calculation of the force arm should be determined according to the position of the mounting hole on the flange of the lead screw nut, and the force arm is not the same for different specifications of nuts
Metro Line 2, Cheng east railway station, exit and train exit together