| Intrinsically safe explosion-proof equipment can make sure that when it is operated under specified conditions of failure or regular working conditions,the heat or electric spark that its circuits generate will not ignite prescribed combustible gas.This thesis has studied the six joint manipulator and analyzed its third joint module in the terms of the intrinsic safety and explosion-proof performance.It referred to a small-power brushless DC motor and a harmonic reducer.First,a heat resource analysis about the driving joint module was conducted and its wastage rate was calculated with empirical formulas.The results showed that the copper loss in the rated conditions and the no-load condition were 11.73W and 1.30W respectively,correspondingly,the single power tube loss of which were 1.47W and 0.51W,the Stator loss was 21.79W and reducer loss was 43.50W.With the data above,the thermal test and simulation on the drive joint module was done with the help of the steady state thermal analysis module of Ansys Workbench,then the temperature rise of dive joint module under the rated and no-load condition were analysed.According to the result,the surface temperature of the driving joint module was up to 50.37? at most in the no-load condition.And in the rated conditions,its surface temperature was not more than 53.22?,but the surface temperature of the PCB board was relatively high,about 93.730C.The thesis also separately analysed some parts that cause the loss such as the stator,reducer and the controlling circuit.Among them,the surface temperature of stator and reducer were not more than 63.91 ? while the highest temperature of PCB board was 97.69?.To prolong the life-span and ensure the reliability of the drive joint module and the components,the thesis optimally designed the heat dissipating capability of the drive joint module.First the thesis change the materials of some components,for example,7050 alluminium alloy,which has an excellent thermal conductivity,is applied to the hull and the adapting flange.The Stator and the reducer and PCB board are the main heat resource,so the air vents were designed on the surface,where the motor shaft connects the reducer and the rotor,to improve its heat dissipation rate.The results indicated that with the optimal design,the maximum temperature of drive joint module in no load condition and rated condition were droped about 2.05? and 2.21? respectively.According to the requirements for the Intrinsically safe circuit in the "GB3836.4-2010 explosive environment section 4 the equipment protected by Intrinsically safe "I"",the thesis added some protection to the external power and provided over current protection for 48V external power using 35A fuse wire.This thesis calculated the amount of electric spark energy generated in the resistive circuit,capacitive circuit and inductive circuit respectively,using calculation formula of electric spark energy.As for capacitances that cannot meet the requirements,the thesis adapts its effective capacitance to limit its energy using the method of serial resistance seal.The value of resistances are 5?,10? and 50?.As for inductance coils that cannot meet the requirements,the thesis connected the freewheeling diode with its two ends to protect its circuit.The measures above can reduce the amount of the electric spark energy,thus making it less likely to ignite the gas mixture in the mine.The electric spark and heat generated by drive joint module are the main factors that cause the ignition of the explosive gas mixture,therefore,the thesis analysed the explosion-proof performance and carried out optimal design for the structure,which improved the safety of the joint module and has great significance to the explosion-proof of the dive joint module. |
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