| 摘要 |
PROBLEM TO BE SOLVED: To provide a revolution-linear motion conversion mechanism employing a roller screw mechanism that makes reduced linear motion per one revolution efficiently. SOLUTION: A roller screw mechanism comprises a shaft 1 having a larger number of external threads, a nut 3 having a larger number of internal threads and a roller 2 having threads adapted to engage with both threads disposed between the shaft 1 and the nut 3. The internal threads of the nut 3 and the external threads of the shaft 1 are opposed to each other. The threads of the roller 2 have a shape with different pitch diameters dR1 and dR2 of two straight lines or curved surfaces joined together. the pitch diameter of threads dS of the shaft 1, and the numbers of threads JN of the nut 3, JR of the roller 2 and JS of the shaft are set so as to meet the following relations using the pitch diameters of threads dN of the nut 3 and dR1 and dR2 of the roller 2 on the crest side and the trough side: dS=(α-γ-1)dR1 , JS=(α-2).JR, and JN=α.JR, whereα=dN/dR1 andγ=dR2 /dR1 .
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