我们本着轴承要密封，以延长使用寿命，轴承组的间距要大，以保持其稳定性和内管可调节的三个原则，设计了SD-Ⅰ型单动双管（见图），在长春地院实习队的协助下，进行了生产试验。从初步结果看：①此双管结构是较为合理的，轴承使用寿命较长；②单动性能大为改善，而且稳定，在破碎地层钻进，有明显的防堵作用，可提高回次进尺；③由于内管可调节，大大缩短了装配时间。（过去是选用不同长度的短节来调整卡簧座和钻头的间隙）；④加工较简单，轴承易买到，便于推广。 We have to seal the bearing, in order to extend the service life, the distance between the bearing group is larger, in order to maintain its stability and the three principles of the inner tube can be adjusted, the SD-I type single action double tube (see figure) is designed. With the assistance of the Changchun District Court practice team, production trials were conducted. From the preliminary results: 1 This double-tube structure is more reasonable, bearing life is longer; 2 single-action performance is greatly improved, and stable, drilling in the broken formation, there is a clear anti-blocking effect, can increase the return footage 3 Because the inner tube can be adjusted, the assembly time is greatly shortened. (In the past, the short joints of different lengths were used to adjust the gap between the retainer and the drill bit.) 4 The machining was relatively simple, the bearings were easy to buy, and they were easy to promote.