关键词: 大变温, 电钻杆, 冠簧式接触件, 装配间隙, 力学特性, 接触性能

Abstract: In order to improve the electrical contact performances of crown spring contacts for electric drill pipes under great temperature variation drilling conditions， the mechanics properties and electrical contact performances of the contacts were studied. Based on the static and thermo-mechanics coupling finite element analysis method， the relationships between the deflection of the reed and the contact pressure， the insertion force and the insertion depth of the pin were analyzed. The variation laws of insertion forces， contact pressures and contact areas for contact parts with different assembly gaps were studied under great temperature variation conditions. The results show that the contact pressure increases with the increase of deflection， and the increases decrease accordingly， and the insertion forces first increase and then decrease with the insertion depths and finally stabilize. The temperature rise causes the contact pressures and contact areas of the contacts to decrease， which reduces the electrical contact performance. When the assembly gap is as 0.07 mm≤δ≤0.2 mm， the impacts on the electrical contact performance are small. Considering the contact pressure， contact area and maximum equivalent plastic strain at 150 ℃， the optimal assembly gap of crown spring contact is as 0.07 mm. The research results may provide references for the structural design and optimization of crown spring contacts for electric drill pipes. 

Key words: great temperature variation, electric drill pipe, crown spring contact, assembly gap, mechanics property, contact performance