Abstract: The front axle is one of the most important parts of truck bearing,which bears loading and torque in different directions.Aiming at checking a new front axle design safety and reliability,the front axle was mechanics analysed and the loading was obtained in the condition of bump,brake,steer and steer-brake.The front axle strength was analysed based on theoretical analysis loading and finite element method by adopting HyperMesh,the result showed that the maximum stress were 379.0,490.9,267.0 and 533.5 MPa in the condition of bump,brake,steer and steer-brake,they were less than yield strength,but safety coefficients of brake and steer-brake condition were less than 1.2,they could not meet the design requirements.Bench test was carried out on the front axle based on four typical working condition,the test point strain datas were obtained,and they were converted to stress by adopting Ncode software.The bench test results showed that test values were close to finite element analysis values,their error rate were less than 10 %.The analysis results showed that the maximum stress were respectively reduced by 21.3 %,17.0 %,28.4 % and 17.3 % in the four typical working condition by smoothing the connections of spring seat and the front beam.The safety coefficients of brake and steer-brake condition were more than 1.2 after optimization,they could meet the design requirements.

Key words: front axle, mechanics analysis, finite element, strength, bench test