For each double cone, the opposite pulls from two parts of the sphere exactly cancel. 就每一双锥面来说,球壳的两个部分所产生的相反引力正好对消。
The die and eqiupment of internal pressurized expanding retaining rings and double cone wedge-reaming die were also studied. 对内增压扩胀护环的装置和双锥面楔块扩孔模具进行了研究。