| 摘要 |
PCT No. PCT/SU86/00008 Sec. 371 Date Sep. 1, 1987 Sec. 102(e) Date Sep. 1, 1987 PCT Filed Jan. 31, 1986 PCT Pub. No. WO87/04753 PCT Pub. Date Aug. 13, 1987.A rotor (1) of a screw hydraulic downhole motor, made as a hollow multiple-start screw featuring a substantially constant wall thickness. The ratio of the length of the rotor (1) cross-sectional outside contour to the length of the circumscribed circle of the contour is substantially within 0.9 and 1.05. When making the rotor (1) a forming element is inserted into a tubular blank, and a fluid pressure is applied to the outside blank surface. A device for making the rotor comprises a hollow housing accommodating a forming element installed on centering bushings. The bushings have fitting areas adapted for the ends of the tubular blank to fit thereon. |
