| 摘要 |
The rotor of a progressive cavity downhole motor includes a mandrel 526 having at least one radial lobe and an elastomeric tubular sleeve compressed about the mandrel so as to establish frictional engagement therebetween. The sleeve may be compressed about the mandrel by processes including: heat and vacuum shrinking, elastic expansion, mandrel insertion and relaxation and roller compression. The sleeve may be circular cylindrical, of triangular, square or oval section or shaped to fit the mandrel and the mandrel may have a grooved surface. Engagement may be enhanced with adhesive. Also disclosed is a method of applying the sleeve to the mandrel (Fig. 8) involving supporting an elastically expanded sleeve (828) on a helically grooved tubular support (815), inserting the mandrel (826) and removing the support by tearing at the groove and unwinding. |
