| The driving mechanism of azimuth angle is the one of the most important driving components of disc type solar tracker device,the driving mechanism of azimuth angle has some features including complicated structure,high tracking accuracy,high wind load requirement,low noise,long service life( ? 20 years)and so on,structure deformation and fatigue failure under wind load which is the main factors influence to azimuth drive tracking precision and service life.In view of some problem of existing external driving mechanism of azimuth angle easy to generate interference and bring the negative effects for the device in the outdoor under the severe environment,this paper designed a kind of built-in azimuth angle transmission mechanism,the mechanical properties and fatigue life analysis were carried out under the 8 level wind load.It has very important significance to the stability,high efficiency and reliability for azimuth drive device.First,the structure characteristics and working principle of the two built-in azimuth drive mechanisms are compared and a structure scheme is determined.The load of azimuth drive device was calculated at the most unfavorable conditions when under the 8 wind load and the elevation angle is 0 degree and wind direction angle is 90~120degrees.Based on the ANSYS Workbench soft ware,the static characteristic was analyzed and the stress cloud of each component of the device was obtained.then,compared with the Hertz theory calculation results.The results shows that:two methods only different in calculation the stress of the idler gear,so,analysis the reasons for this kind of situation and adjust the train of thought.Second,upon the azimuth transmission load has particularity and it subject to time-varying under random wind load.In order to avoid only consider static strength and may result in local structure irrationality,using the linear filtering method based on the actual working condition,through the MATLAB software to simulate wind speed time history curve and got the load spectrum curve.Then,The modal analysis and transient dynamics was carried out.Modal analysis results obtained the gear first six levels of frequency and vibration mode,it verify the feasibility and reliability of the gear transmission mechanism.From the transient dynamics calculation result wecan see that the stress concentration position as same as the statics analysis results,and tooth root bending fatigue test shows that the design of gear transmission mechanism satisfies the requirement of strength and stiffness.Finally,the transmission device fatigue life analysis was analyzed through the SN stress fatigue analysis by the nCode Design Life software.The cycle times of transmission mechanisms under fluctuating wind load to be destroyed is obtained.The results shows that two positions of the most easily damaged is on the idler wheel connected with the gear shaft gear and worm gear meshing.Its service life is 3.194e5 times and 2.096e4 times,in accordance with the requirements of life design. |
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