Research of Hydraulic Actuator using Oil mixed with Air as a Power Transmission Medium

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K18076
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Design engineering/Machine functional elements/Tribology; Fluid engineering
• Research Institution: National Institute of Advanced Industrial Science and Technology (2019); Aoyama Gakuin University (2017-2018)
• Principal Investigator: SAKAMA Sayako 国立研究開発法人産業技術総合研究所, 情報・人間工学領域, 産総研特別研究員 (70773539)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 油圧動力伝達システム / 作動油 / 気泡 / 体積弾性係数 / アクチュエータ / 衝撃吸収

Outline of Final Research Achievements

In this study, to develop an actuator that has both a large generated force and a shock absorbing effect,we have developed a new hydraulic cylinder that uses oil containing air bubbles as a power transmission medium.
To evaluate the characteristics of this cylinder, we modeled the relationship between the pressure and the effective bulk modulus of hydraulic oil containing bubbles, and evaluated the effect of entrained air on the characteristics of the cylinder by numerical analysis. Moreover, we also conducted some experiments using a prototype for its characteristic evaluations. As a result, it was clarified that the effect of the compressibility of entrained air in oil on the decrease in responsiveness is slight, while it is effective for shock absorption.

Free Research Field

油圧制御

Academic Significance and Societal Importance of the Research Achievements

本研究で開発したシリンダは，力の発生だけでなく，衝撃を吸収する役割も担うことから，別途衝撃を吸収する機器を取り付ける必要がなく，アクチュエータ部をコンパクトに設計することが可能となる．
また，空気の圧縮性は力の伝達効率を低下させるため，一般的には作動油中の気泡は積極的に除去することが望まれるが，油圧システム中の気泡を完全に取り除くことは困難であり，気泡は常に油中に混入していると仮定して機器を利用する必要がある．本研究で得られた成果は，作動油中に気泡が混入した油圧システムの解析，制御等にも役立つ有用な知見が多く得られており，あらゆる油圧機器の性能向上への貢献が期待できる．