Calculate the mean value of the torsion strength of the wire and the standard deviation of the standard deviation of the torsion strength σ_B=1800219501650=+N/mm2 the torsion yield limit of the wire τ_s=0.4537×σ_B=0.4537×1800=816.66N/mm2 variation coefficient C1=017.0180025= C2=028.018006300616501950=Bσ21028.0017.0+=+=cCTS=0.033 standard deviation Sτs=Cτs×τ_s=0.033×816.66=26.95N/mm2. Calculate the mean value of the working torque of the spring wire and the standard deviation spring curvature coefficient 21.1615.0414=Ck (Rotation ratio C=D/d=14/2.5=5.6) Variation coefficient Ck=KSK=037.021.1045.0=Working torsional stress mean: 38×=dDFkπτ=35.2143.25821.18×π=713.11N/mm2 Permissible by load Deviation ± △ F = 0, determine the standard deviation SF = △ F / 3 = 0, the coefficient of variation CF = △ F / (3F) = 0 find Cd = 0.004, CD = 0.0033, then the comprehensive coefficient: 29dDKCk + = τ2004 .09033.0037.0×+==0.039Standard deviation Sτ=Cτ×τ―=0.039×713.11=27.84N/mm21.5 Calculate the reliability index estimate. Since Cτ=0.037<0.07; CΤs=0.033<0.07, that is, the coefficient of variation of each random variable is relatively small, and the torsional stress approximates the normal distribution, the reliability index can be calculated by using the normal strength and normal stress interference model. Value ZR: 227.2657.2593.70966.816=τSZSR9113.266.3673.106=1.6 Estimate the lower limit of reliability by 95% confidence. Pass the calculation of reliability, and then test the spring to determine its reliability. Confidence range. Because of the confidence that the lower limit of reliability is known, the reliability with confidence is of real practical value. The strength stress sample size is nx=16, the stress sample capacity is ny=11; the mean and standard deviation of the strength sample and the stress sample are calculated from 2.2 and 2.3: s=816.66N/mm2, the standard deviation is Sτs=25.31N/mm2; the average working torsional stress is 709.93N/mm2; the standard deviation Sτ=26.27N/mm2. The effective sample capacity nC is: 1)(442+=yxScnSnSnτ11127. 2611631.25) 27.2631.25 (442=23.62 by, when nc=23.62, Zk=2.9113, the reliability lower limit RL=0.995 is found, which indicates that the reliability of the spring is greater than 0.995 with 95% confidence. Conclusion (1) The spring used in the torque tester is in the specified design requirements, and its reliability can ensure that the wrench will not be affected by the accuracy of the pre-tightening static pressure when the spring is used. (2) By optimizing the experiment and reliability calculation of the spring, the design size and actual size of the spring are further optimized, so that the structure of the whole wrench is more compact and beautiful. (3) Other types of springs and the reliability and confidence analysis of the normal strength and normal stress interference model can be calculated by referring to the above method. Aluminum U-shaped Baffle Ceiling LED Light Foshan Nanhai Lianxing Deli Decoration Materials Co.,Ltd , https://www.fstuodeli.com