Construction of active method of controlling contact-friction condition in hydraulic half-floating leadscrew using rate of separation as reference valuable

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K04148
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 18040:Machine elements and tribology-related
• Research Institution: Shinshu University
• Principal Investigator: Fukada Shigeo 信州大学, 学術研究院工学系, 教授 (70156743)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: すべり送りねじ / 半浮上状態 / 円筒状モデル / 油圧 / 分離度

Outline of Final Research Achievements

In order to realize an ideal leadscrew with both of low friction and high stiffness, this study refers to a ‘hydraulic half-floating sliding bearing’which decreases apparent frictional coefficient by providing appropriate fluid pressure without full-separation between frictional surfaces, and considers experimentally on an active method of controlling contact-friction condition to provide both of minimum friction and high stiffness. Some experiments were performed using a simplified model whose cylindrical end surfaces correspond to actual screw thread of Tr30×8. A triple cascade control system was constructed with PID controllers, and it made the rate of separation possible to follow sinusoidal reference by operating the parallel control system of pressure-separation and displacement-separation simultaneously.

Free Research Field

精密工学

Academic Significance and Societal Importance of the Research Achievements

工業製品を高精度に製造する工作機械の直動ガイドや送りねじでは，精密な動作を実現するために摩擦の低減と負荷に対する剛性の向上が同時に要求される．しかし一般に両者は相反する特性であり，それらの二つの要求を同時に満たすことは困難であった．本研究は，低摩擦と高剛性を両立させるために二面が分離しない程度の流体圧を接触面間に供給して摩擦係数を低減する‘油圧半浮上すべり面’に着目し，実際の接触状態に応じて流体圧を浮上直前まで増大して摩擦を限界まで低減して摩擦の最小化と高剛性を両立する接触・摩擦状態の能動的な制御方法を実現した．本方法を送りねじに応用することで，低摩擦で高剛性な位置決め要素を実現できる．