Design And Research Of Fatigue Life Test-Rig For Slewing Bearing Based On LabVIEW

Slewing bearing consists of the rotational connection between two substructures for combined load at very low speed.Due to its higher capacity in supporting axial force,radial force and overturning moment compare with ordinary bearing,it is widely used in port hoisting machinery and ocean engineering equipment.With the increasing requirement of higher life and performance indicator for the slewing bearing,the measurement of fatigue life for slewing bearing has been an urgent problem.Although there are a large number of traditional or modern techniques applied to slewing bearing,they may not be able to meet the requirement of bearing industry precisely due to the significant difference between the ordinary bearings and the slewing bearing,thus,the experiment is the most effective and reliable method.In this paper,the main forms of fatigue failure for slewing bearing in practical application are described on the basis of related theories.A special test machine for slewing bearing is presented and an accelerating fatigue life test method based on the equipment is proposed to predict the whole fatigue life of the slewing bearing.Then the accelerating fatigue life test model is built and the test machine is described in detail from the aspects of integral structural design,loading system,drive system and monitoring system.And the finite element model of the test machine is established to check its overall strength and stiffness.A virtual instrument test system using vibration and temperature detection is built whose hardware is constructed by temperature and acceleration sensor,electric relay,data acquisition card and the industrial personal computer in this paper.Its software platform is based on LabVIEW.Then the approaches to software programming,design of the test and failure criteria are described.Finally,the test for a pair of slewing bearings is completed in the laboratory.A test theory based on the test-rig is given and the data obtained by the experiment is analyzed as the performance indicator of the slewing bearing.It is shown that the presented test equipment can meet the high reliability requirement of the fatigue life test for slewing bearings under actual working conditions.