Updated on 2022/05/26

写真a

 
TOMIOKA, Jun
 
Affiliation
Faculty of Science and Engineering, School of Fundamental Science and Engineering
Job title
Professor

Concurrent Post

  • Faculty of Science and Engineering   Graduate School of Fundamental Science and Engineering

Research Institute

  • 2020
    -
    2022

    理工学術院総合研究所   兼任研究員

Degree

  • 工学博士

Professional Memberships

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    ASAIO

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    JSAO

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    LST

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    JSDE

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    JAST

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    JSME

▼display all

 

Research Areas

  • Design engineering

  • Machine elements and tribology

Papers

  • 修正平均流モデルを用いたメカニカルシールの潤滑解析(第2報,歪みと尖りの影響)

    富岡淳, 大籔美貴子, 湯澤央恵, 宮永宜典

    設計工学   53 ( 8 ) 595 - 604  2018.08

     View Summary

    <p>The aim of this research is to establish the modified average flow model for applying to mechanical seals with parallel sealing faces. In the first paper, the effects of the root mean square roughness on the lubrication characteristics were investigated by the model, assuming that the probability density function of the roughness follows the normal distribution. In this paper, the flow factors are evaluated for smoothly finished surfaces with the several different skewness and kurtosis. The lubrication characteristics of mechanical seals are calculated by using these factors. The results show that as skewness decreases, the film thickness and frictional coefficient decrease. In addition, the flow rate has the lowest value at certain skewness. On the other hand, the film thickness, flow rate and frictional coefficient decrease as kurtosis decreases.</p>

    DOI CiNii

  • 修正平均流モデルを用いたメカニカルシールの潤滑解析(第1報,二乗平均平方根粗さの影響)

    富岡淳, 大籔美貴子, 湯澤央恵, 宮永宜典

    設計工学   53 ( 8 ) 581 - 594  2018.08

     View Summary

    <p>The purpose of this study is to propose a modified average flow model that can be used for mechanical seals with parallel sealing faces, and clarify their lubrication characteristics. The general average flow model established by Patir et al. could not consider the effects of surface roughness between parallel faces. In the present model, the flow factors with considering side leakage effects between parallel lubricating faces are implemented. In addition, the model allows one to consider the additional expected hydrodynamic pressure generated owing to the relative motion of rough surfaces. The flow factors are evaluated as the average for several different surfaces with the same statistical properties. In this first report, the effects of the root mean square roughness on the lubrication characteristics are investigated, assuming that the probability density function of the roughness follows the normal distribution. The results show that as the root mean square roughness increases, the flow rate increases. In addition, the optimal roughness for the friction coefficient is changed with the rotational speed.</p>

    DOI CiNii

  • A Proposal for the Measurement Method of Plasma Component Leakage and Blood Cell Component Leakage in Mechanical Seals under Blood Sealing

    Jun TOMIOKA, Mikiko OYABU, Kohei FUKUI, Kento SAITO, Norifumi MIYANAGA

    設計工学   53 ( 3 ) 251 - 260  2018.03

  • Blood sealing properties of magnetic fluid seals

    Jun Tomioka, Norifumi Miyanaga

    TRIBOLOGY INTERNATIONAL   113   338 - 343  2017.09  [Refereed]

     View Summary

    Shaft seals for rotary blood pumps have strong demands for low friction, very little leakage, and long-term use. Magnetic fluid seals have attracted attention as promising candidates for this purpose owing to their properties of having zero leakage, no wear, and relatively small viscous friction at the same time. In this study, the sealing performance including the maximum sealing pressure and the sealing durability under blood sealing is discussed. In addition, hemolysis tests for blood sealed by magnetic fluids are performed from the viewpoint of biological compatibility. The magnetic fluid seals are found to have adequate sealing durability and pressure resistance in the blood. In addition, hemolysis of blood sealed with the organic-solvent magnetic fluid seals is maintained below 0.5%.

    DOI

  • Effect of acid washing of SiC particles on dispersing and friction properties of Ni-P-SiC composite plating

    Norifumi Miyanaga, Shigeaki Minamikawa, Jun Tomioka

    Key Engineering Materials   739   143 - 147  2017

     View Summary

    This study investigated the effect of acidic solutions used in the washing process of SiC particles on the dispersibility of the particles in a nickel matrix. In addition, the friction behavior of the composite plating was investigated by sliding friction tests. As the results, by washing SiC particles with a HCl solution, the particles appeared in clumps and the rougher surface was created. On the other hand, by a HNO3 solution, the particles appeared with the homogeneous distribution, and thus the surface deposited was smoother. The Ni-P-SiC composite plating shows the lower friction force especially in the range of the slow sliding speed.

    DOI

  • Stability Analysis of Herringbone-Grooved Aerodynamic Journal Bearings for Ultra High-Speed Rotations

    Norifumi Miyanaga, Jun Tomioka

    International Journal of Materials, Mechanics and Manufacturing   4 ( 3 ) 156 - 161  2016.08

  • Effect of support stiffness and damping on stability characteristics of herringbone-grooved aerodynamic journal bearings mounted on viscoelastic supports

    Norifumi Miyanaga, Jun Tomioka

    TRIBOLOGY INTERNATIONAL   100   195 - 203  2016.08  [Refereed]

     View Summary

    Journal bearings mounted on viscoelastic supports are often used to improve the stability. However, proper support conditions have not been established especially for herringbone-grooved aerodynamic journal bearings. This study aims to make clear the effect of support stiffness and damping on the stability characteristics of the bearings. For that purpose, the linear perturbation analysis and the nonlinear transient analysis are performed for various viscoelastic support conditions. This investigation reveals that the groove configuration that gives the highest threshold speed of whirl instability changes with the viscoelastic support conditions. This investigation also reveals that it is possible to stabilize the bearings by viscoelastic supports. However, the threshold speed for lower damping support conditions decreases rather than that for rigid support condition. (C) 2016 Elsevier Ltd. All rights reserved.

    DOI

  • Stability Threshold of Herringbone-Grooved Aerodynamic Journal Bearings with Considering Frequency Dependence of External Stiffness and Damping Elements

    MIYANAGA Norifumi, TOMIOKA Jun

    JOURNAL OF JAPAN SOCIETY FOR DESIGN ENGINEERING   51 ( 6 ) 427 - 440  2016.06

     View Summary

    Herringbone-grooved aerodynamic journal bearings supported by external stiffness and damping elements such as O-rings offer the higher stability. In the previous paper the authors presented the stability charts of the bearing systems using the liner Voigt model simulating external stiffness and damping elements. However, the effect of bearing-support-elements on the stability of the bearing systems is not fully clarified because of their frequency dependence. In addition, the nonlinearity has prevented comparisons between theoretical and experimental results. This study, therefore, investigates the effect of the frequency dependence of bearing-support-elements (O-rings) on the stability threshold of the herringbone-grooved aerodynamic journal bearings. This paper, first of all, clarifies the dynamic properties of O-rings under bearing supporting up to 8 kHz and proposes new empirical formulae for their stiffness and damping coefficients. Subsequently, the stability threshold of the bearing systems is calculated using the empirical formulae and compared with the experimental one. Results show that the stiffness coefficients increase exponentially with the frequency while the damping coefficients decrease and then converge on constant. The predicted stability threshold has good agreement with the experiments.

    CiNii

  • Effects of hematocrit of the sealed blood on the leakage characteristics of blood cell component and plasma component in a mechanical seal

    Jun Tomioka, Mikiko Oyabu, Norifumi Miyanaga

    Tribology Online   11 ( 5 ) 568 - 574  2016

     View Summary

    The purpose of this study is to find out the effects of hematocrit of the sealed blood on the leakage characteristics of blood cell components and plasma components in a mechanical seal, which separates blood from cooling water. The hematocrit was controlled to 0, 10, 20, 30 and 40%. Each component leakage was obtained by measuring the increase in the potassium ion concentration and the sodium ion concentration in the cooling water. It was revealed that each component leakage became larger with the increase of the hematocrit in the three-hour measurement. When changing the hematocrit from 20% to 30%, the volume percentage of the blood cell component leakage remarkably increased by 7.7 times. The friction characteristics of the mechanical seal under blood sealing and the hemolytic properties of the sealed blood were also studied. There is a typical trend under the mixed lubrication condition where the friction torque decreased with each of the sealed blood as the rotational speed increased. The hemolytic index of the sealed blood after the measurement experiments of the blood leakage increased with the increase of the hematocrit.

    DOI

  • Effect of dynamic properties of support O-rings on stability of herringbone-grooved aerodynamic journal bearings

    Norifumi Miyanaga, Jun Tomioka

    Tribology Online   11 ( 2 ) 272 - 280  2016

     View Summary

    This paper discusses the stability of herringbone-grooved aerodynamic journal bearings supported by rubber O-rings. In this research, the dynamic stiffness and the damping properties of the O-rings are identified in a variety of operating and design conditions. The identification results are fitted with the empirical formulae previously proposed, and the distributions of the dynamic properties in a variety of support conditions are obtained. It is theoretically investigated how the stability of the bearing system changes with the dynamic properties. The bearing tests are also performed to verify the analytical results with the empirical formulae. The empirical formulae used here was reasonable for simulating the dynamic properties of the O-rings in a variety of bearing support conditions. The comparisons between the analysis and experiments verified the effectively of analyzing the stability of the bearing system by using the empirical formulae.

    DOI

  • An Analysis of the Lubrication Characteristics of Mechanical Seals with Parallel Sealing Faces Using an Average Flow Model

    Mikiko OYABU, Jun TOMIOKA

    Key Engineering Materials   656-657   615 - 612  2015.07

  • 血液密封下のメカニカルシールにおける血漿成分および血球成分の漏れ量測定方法の提案

    富岡淳, 大籔美貴子, 福井康平, 齋藤健斗, 宮永宜典

    設計工学   50 ( 4 ) 194 - 199  2015.04

  • Investigations of cylindrical and conical whirl instabilities on hydrodynamic journal bearings

    Norifumi Miyanaga, Jun Tomioka

    Key Engineering Materials   656-657   688 - 693  2015

     View Summary

    Hydrodynamic journal bearings induced serious shaft vibrations called oil whirl. Since they often give severe damages to the mechanical systems, it is important to fully understand the phenomenon to avoid the occurrence by the proper bearing design. This study theoretically and experimentally investigated both cylindrical and conical whirl instabilities, which can be appeared in journal bearings, and their relation was discussed. As the result, the span length of the bearings had a significant effect on the vibration mode. The transitional state in which the cylindrical and conical whirl instabilities alternately appeared was observed.

    DOI

  • Development of herringbone-grooved aerodynamic journal bearing systems for ultra-high-speed rotations

    Norifumi Miyanaga, Jun Tomioka

    Key Engineering Materials   656-657 ( 656-657 ) 652 - 657  2015

     View Summary

    It is absolutely important for ultra-compact rotational machineries to achieve sable shaft rotation at ultra-high-speed. This paper discussed herringbone-grooved aerodynamic journal bearing systems developed for the purpose. In this system, the bearings are supported by rubber-O-rings for accurate and stable operations. To grasp the possibility for stabilization, two types of O-rings with different stiffness and damping properties under bearing supporting were tested in the experiment. As the results, the bearing system demonstrated the maximum rotational speed over 460,000 rpm without unstable phenomenon called whirl. However, the difference in rubber O-rings definitely affected the stability of the bearing system.

    DOI

  • Study of Stability-Boundary-Circles within the Bearing Clearance Using the Nonlinear Orbit Method

    Jun TOMIOKA, Norifumi MIYANAGA, Yuichi USHIO, Makoto MIKAMI

    設計工学   49 ( 4 ) 217 - 223  2014.04

  • Effect of surface roughness of mechanical seals for rotary blood pumps under blood sealing

    Jun Tomioka, Norifumi Miyanaga

    JOURNAL OF ADVANCED MECHANICAL DESIGN SYSTEMS AND MANUFACTURING   8 ( 1 )  2014  [Refereed]

     View Summary

    A miniature mechanical seal with the cooling water circulating system has been developed as a solution of the shaft seal problems in rotary blood pumps. The present paper describes the effect of the surface roughness in the sealing gap on the shaft seal problems under blood sealing. The sealing surface roughness of tested three seat rings were designed to be Ra=0.009, 0.088 and 0.170 mu m. The frictional loss torque in the sealing gap and the leakage of the blood and the cooling water were measured in this work. Results show that the maximum frictional loss torque measured in the seat ring of Ra=0.009 mu m, and the frictional loss torque decreased as the surface roughness increased. The leakage rate of the cooling water is larger than that of the blood in all seat rings, even though the blood chamber has higher pressure. The sealing characteristics between under the blood and water sealing were different. Moreover, the best surface roughness in the torque and the leakage characteristics were also different. Thus, it is important to study under blood sealing in the design of the surface roughness of the mechanical seals for rotary blood pumps.

    DOI

  • Stability Threshold of Herringbone Grooved Aerodynamic Journal Bearings with External Stiffness and Damping Elements

    Jun Tomioka, Norifumi Miyanaga

    JOURNAL OF ADVANCED MECHANICAL DESIGN SYSTEMS AND MANUFACTURING   7 ( 6 ) 876 - 887  2013  [Refereed]

     View Summary

    Herringbone grooved aerodynamic journal bearings have better stability characteristics than plane aerodynamic journal bearings. In addition, the use of flexibly supported bearings is one of the efficient way to improve the bearing stability. Therefore, the combination bearing systems have prospects of realization of ultra-high-speed operations. The purpose of this work is to evaluate the effect of external stiffness and damping elements on the bearing stability. The Voigt rheological model was used for the external elements, in which the stiffness and the damping were treated as the linear elements. It was clarified that the stability boundary of the herringbone grooved aerodynamic journal bearings supported by suitable stiffness and damping elements can be heightened more than three times compared with the rigidly supported bearings.

    DOI

  • 507 Effects of Statistical Property of Surface Roughness on the Correction Factors in Average Flow Model : 3rd Report, Effects of Skewness

    OYABU Mikiko, TOMIOKA Jun

      2012 ( 20 ) 121 - 122  2012.08

     View Summary

    The surface roughness of sealing face has effects on the characteristics of mechanical seals. An average flow model has been applied to the lubrication problems considering those effects. However, that model is limited to a type of normally-distributed surface roughness despite of a number of lapped surfaces which have non-normal distribution. Therefore, this study focuses on the skewness of surface roughness and investigates the effects of that on the correction factors in the average flow model. As a result, the smallest pressure flow factors were obtained under negative skewness. The pressure flow factor has effects on the leakage rate of mechanical seals, so that the surface roughness has negative skewness results in small leakage.

    CiNii

  • 723 Effects of Statistical Property of Surface Roughness on the Correction Factors in Average Flow Model(2nd Report, Effects of Kurtosis)

    OYABU Mikiko, TOMIOKA Jun

      2012 ( 61 ) "723 - 1"-"723-2"  2012.03

    CiNii

  • Stability Threshold of Herringbone-Grooved Aerodynamic Journal Bearings with Considering Temperature Characteristics of Support O-rings

    MIYANAGA Norifumi, TOMIOKA Jun

    Journal of Japan Society for Design Engineering   46 ( 9 ) 530 - 535  2011.09

    CiNii

  • Stability Threshold of Herringbone-Grooved Aerodynamic Journal Bearings with Considering Temperature Properties of Support Elements (1st Report, Experimental Study)

    YOKOYAMA Shinpei, MIYANAGA Norifumi, TOMIOKA Jun

    Journal of Japan Society for Design Engineering   46 ( 8 ) 414 - 416  2011.08

    CiNii

  • Stability Threshold of Herringbone-Grooved Aerodynamic Journal Bearings with Considering Frequency Dependence of External Stiffness and Damping Elements

    MIYANAGA Norifumi, TOMIOKA Jun

    Journal of Japan Society for Design Engineering   46 ( 4 ) 231 - 238  2011.04

    CiNii

  • Effect of surface roughness of mechanical seals under blood sealing

    Jun Tomioka, Norifumi Miyanaga

    LUBRICATION SCIENCE   22 ( 10 ) 443 - 452  2010.11  [Refereed]

     View Summary

    A miniature mechanical seal with cooling water circulating system has been developed as a shaft seal for rotary blood pumps. The present paper describes the establishment of the experimental methods under blood sealing and the estimation of the effect of the surface roughness on the shaft seal problems, especially in the increase of the friction and the leakage. Micro-leakage rates of the blood and the cooling water were measured by an ion chromatography. In this method, the ion concentration was converted into the leakage rate. The frictional loss torque was measured by a torque meter. Results are provided with three types of surface roughness, Ra = 0.009 mu m, Ra = 0.088 mu m and Ra = 0.170 mu m. It is shown that as the surface roughness increases the leakage decreases while the frictional loss torque increases under blood sealing. The best surface roughness in the torque and the leakage characteristics were different. Copyright (C) 2010 John Wiley & Sons, Ltd.

    DOI

  • Study of Stability-Boundary-Circles within the Bearing Clearance Using the Nonlinear Orbit Method

    TOMIOKA Jun, MIYANAGA Norifumi, USHIO Yuichi, MIKAMI Makoto

    Journal of Japan Society for Design Engineering   45 ( 11 ) 563 - 568  2010.11

    CiNii

  • Effect of Surface Roughness of Mechanical Seals for Rotary Blood Pumps under Blood Sealing(Machine Elements, Design and Manufacturing)

    TOMIOKA Jun, MIYANAGA Norifumi

    Transactions of the Japan Society of Mechanical Engineers. C   76 ( 769 ) 2332 - 2339  2010.09

     View Summary

    A miniature mechanical seal with the cooling water circulating system have been developed as a solution of the shaft seal problems in rotary blood pumps. The present paper describes the effect of the surface roughness in the sealing gap on the shaft seal problems under blood sealing. The sealing surface roughness of tested three seat rings were designed to be Ra=0.009μm, Ra=0.088μm and Ra=0.170μm. The frictional loss torque in the sealing gap and the leakage of the blood and the cooling water were measured in this work. Results show that the maximum frictional loss torque measured in the seat ring of Ra=0.009μm, and the frictional loss torque decreased as the surface roughness increased. The leakage rate of the cooling water is larger than that of the blood in all seat rings, even though the blood chamber has higher pressure. The sealing characteristics between under blood and water sealing were different. Moreover, the best surface roughness in the torque and the leakage characteristics were also different. Thus, it is important to study under blood sealing in the design of the surface roughness of the mechanical seals for rotary blood pumps.

    CiNii

  • Stability Threshold of Herringbone Grooved Aerodynamic Journal Bearings with External Stiffness and Damping Elements(Machine Elements, Design and Manufacturing)

    TOMIOKA Jun, MIYANAGA Norifumi

    Transactions of the Japan Society of Mechanical Engineers. C   76 ( 767 ) 1812 - 1818  2010.07

     View Summary

    Herringbone grooved aerodynamic journal bearings have better stability characteristics than plane aerodynamic journal bearings. In addition, the use of the flexibly supported bearings is one of the efficient way to improve the bearing stability. Therefore, the combination bearing systems have prospects of realization of ultra-high-speed operations. The purpose of this work is to evaluate the effect of the external stiffness and damping elements on the bearing stability. The Voigt rheological model was used for the external elements, in which the stiffness and the damping were treated as the linear elements. It was cleared that the stability boundary of the herringbone grooved aerodynamic journal bearings supported by the suitable stiffness and damping elements can be heightened more than three times compared with the rigidly supported bearings.

    CiNii

▼display all

Books and Other Publications

  • 役にたつ機械製図第2版―学生からエンジニアまで―

    林洋次, 富岡淳, 神野秀基, 関谷弘志, 中村昌雄, 丹羽三樹弥, 藤尾昇, 本田康裕, 山本隆司, 若林克彦

    朝倉書店  2013.09

  • 最新 材料の力学

    邉吾一, 藤井透, 川田宏之, 青木義男, 大窪和也, 粕谷平和, 片山傅生, 末益博志, 高橋清造, 竹村兼一, 田中和人, 田中達也, 陳玳珩, 富岡淳, 橋本純, 福田弘, 森山裕幸, 康井義明, 依田満夫

    培風館  2008.04

  • 役にたつ機械製図—学生からエンジニアまで—

    林洋次, 富岡淳, 神野秀基, 中村昌雄, 丹羽三樹弥, 藤尾昇, 本田康裕, 柳内雅雄, 山本隆司, 若林克彦

    朝倉書店  2004.09

  • 標準 材料の力学

    邉吾一, 藤井透, 川田宏之, 青木義男, 大窪和也, 大瀧誠一, 粕谷平和, 片山傅生, 宗宮詮, 高橋清造, 竹村兼一, 谷本敏夫, 富岡淳, 中田政之, 成田吉弘, 福田弘, 康井義明, 依田満夫

    日刊工業新聞社  2001.03

Research Projects

  • Blood sealing characteristics of mechanical seals for rotary blood pumps using a new mean flow model

    Project Year :

    2017.04
    -
    2020.03
     

  • Study on Desing Method of Air Bearings with Considering Hofp Bifurcation

    Project Year :

    2017.04
    -
    2020.03
     

  • Study on Hopf bifurcation of Journal bearings and its applications

    Project Year :

    2014.04
    -
    2017.03
     

     View Summary

    In this study, we investigated a hopf bifurcation phenomena of journal bearings and applied it to their stability analysis. Further more, we obtained types and periodic solutions of the bifurcations occured in the bearings, performed the stability analysis with the nonlinearlity of the fluid film. As a result, in a subcritical bifurcation region, the vibration amplitude of the shaft immidiately increased even lower speed of stability limit. On the other hand, in a supercritical bifurcation region, the vibration amplitude of the shaft increased with the periodic solution even higher speed of stability limit

  • Design aimed at minimizing the leakage amount of the mechanical seal for blood sealing

    Project Year :

    2014.04
    -
    2017.03
     

     View Summary

    Design aimed at minimizing the leakage amount of the mechanical seal for the rotary blood pump is revealed in this study. Firstly, each leakage characteristics of blood cell components and plasma components are revealed with the new measurement method. Each leakage characteristics is found out in detail by changing the hematocrit of the sealed blood. Secondly, the average flow model in the parallel sealing faces to provide stochastically the design guide for the surface roughness distribution on the sealing faces is proposed. The effects of the statistical properties of the surface roughness distribution on the flow factors are also found out. Finally, the lubrication characteristics of the mechanical seal considering the surface roughness effects are shown with the new average flow model. In addition, the analytical results are compared to the experimental results

  • Effect of the rheological properties of the blood and the surface roughness of the mechanical seals for rotary blood pumps

    Project Year :

    2011.04
    -
    2014.03
     

     View Summary

    The effect of the immobilization of red blood cells on rheological properties and hemolytic characteristics was clarified.Sealing properties of a mechanical seal for blood using an electrical conduction meter and an ion chromatography were clarified.An average flow model to predict the lubrication characteristics of mechanical seals with parallel sealing faces is proposed. The present model determines the flow factors considering the two-dimensional flow under the similar operating conditions of mechanical seals. The correction factor for the expected hydrodynamic pressure generated by the surface roughness is also defined. The results are compared with those based on the Patirs average flow model and show that the present model can be effective for the analysis of the lubrication characteristics of mechanical seals with parallel sealing faces

  • 人工臓器素材開発

    文部科学省 

    Project Year :

    1996
    -
    2000
     

  • 生体模倣部品開発プロジェクト

    文部科学省 

    Project Year :

    1999
     
     
     

  • Development of a Internationally acceptable fatigue test system for prosthetic heart valve

    Project Year :

    1994
    -
    1996
     

     View Summary

    The purpose of this study is to establish an internationally-acceptable methodology of fatigue testing for prosthetic heart valves, based on the improvement process of a Chinese-made accelerated fatigue test apparatus. This test system had four parallel water cylinders, in which valves were incorporated. Open and closing motion of each valve was controlled at a repetition speed of 10-20 Hz with a displacement of 1-2mm. The Jerryfish (JF) valve was used in this study. It had the longest implantation record in animal trials. In this case, the polyurethane membrane with the thickness of 50-70 mum was ruptured due to a creep effect observed at the middle portion between two spokes after 300days in goat.
    First of all, in vitro fatigue test machine has been innovated in order to reproduce the above mentioned in-vivo fatigue test results. Dynamic conditions which enabled the identical forces between accelerated and normal cycles were determined : maximum load during valve closure was 5.2N (increased by 20% to the normal), and impulse was 2.5*10^<-2>N・s. Under this condition, valves were ruptured for 1.0*10^7 cycles, but no distinct creep was noticed. Secondary, a temperature of the test-fluid was changed from 20゚C to 50゚C,expecting a creep effect to the membrane shape. Change in shape of the membrane was observed after 3.2*10^6 cycles, however, its distortion value was only 50% of the animal experimental results. For the next step, a material of the membrane was changed from polyurethane to polystirene to achieve bigger change in shape. As a result, the identical distortion level was successfully reproduced, but a location of the ruptured area was different between in vitro and in vivo results. In order to clarify the above mentioned difference, FEM analysis was performed. The calculated result exhibited that there are three major areas of the maximum elastic strain between two spokes. Moreover, it was confirmed that the ruptured areas observed by both in vitro/in vivo results could be fully superimposed to the areas of the calculated maximum elastic strain.
    Further investigation should by carried out to determine more reliable methodology for fatigue testing, based on the in vitro and FEM analysis data.

  • 潤滑剤の非線形粘弾性特性がジャーナル軸受の安定性に及ぼす影響

     View Summary

    潤滑剤の諸特性を改善するために多量の高分子重合物を添加した潤滑油は,粘弾性挙動を示すことが知られている.この粘弾性挙動が軸の安定性に及ぼす影響を,理論的に明らかにすることが本研究の目的である.研究方法としては,まず粘弾性モデルとして線形2要素モデルを用い,基礎方程式を流体潤滑理論に適用し潤滑方程式を得て,さらにこれを無限長幅ジャーナル軸受に適用し,非線形偏微分方程式を得る.圧力の線形近似と,軸の微少振動を正弦波と仮定した「近似解法1」,圧力の線形近似を高次の項まで考慮した「近似解法2」の2通りの解き方によりこの方程式を解いて圧力,油膜力,油膜係数を求める.ここで中央にロータを持ち両端で軸受に支えられている弾性軸の系を考え,その振動方程式から導かれた特性方程式に油膜係数を代入して安定限界線図を求める.その結果,「近似解法1」から油膜係数について,弾性係数は粘弾性流体の方がニュートン流体よりも高くなり,粘性係数については逆に粘弾性流体の方が低くなった.また安定限界線図から潤滑剤として粘弾性流体を用いると中偏心率では不安定領域が広がり,低偏心率及び高偏心率では逆に安定領域が広がった.「近似解法2」では近似の次数が低いときには「近似解法1」と同じような結果を得ることができたが,高くなると結果が不安定になった

  • Development of viscoelastic tubes similar to blood pump

     View Summary

    The purpose of this study was to fabricate viscoelastic tubes, which was anatomically identical and functionally equivalent to the natural aorta. A rotational molding workstation which was originally developed at the National University of Singapore was used for this research. First of all, we tried to fabricate aortic arch-shaped tubes by a conventional method ; a single rotational axis was employed after silicone liquid was painted onto the mold by a brush. However, it was hard to make an even thickness tube, and it was also hard to control the quality. For the next step, several trials and errors were conducted using a rotational molding workstation under various combination of rotational speeds between two axis with different painting volume, interval and times. At last, the optimal condition to develop 1mm-thickness tube was determined as follows : rotational speeds of major and minor axis were 0.02rpm and 8rpm, respectively, a weight of silicone was 20g each for three times, and painting interval was 3hours. Then, thickness deviation which was defined as a ratio between standard deviation and average thickness culd be reduced from 30% to 20%.It was well-known that natural aorta had specific mechanical properties ; increase in pressure is small for the range of less incremental volume, whereas it becomes more for the range of higher incremental volume. We have tried to fabricated multi-layr tube, however, we haven't get a favorable result. So, other trials that contained different properties from silicone was carried out. A sponge layr was sandwiched with soft and stiff silicone layrs. The compliance values of this 3-layr tube was 0.41 1/mmHg in the range of small incremental volume up tp 40%, but it was decreased to 0.36 1/mmHg for over 40%, due to a shift of major elasctic effects from outer stiff to inner soft silicon layr.Above findings were worthwhile for the further improvements of the rotational molding machine

  • Prediction of durability of artificial organs using an accerelated fatigue tester

     View Summary

    In order to predict a durability of heart valve prostheses, two types of commercially available (ISU-Standard) accerelated fatigue tests were employed, while improving a life time of Jellyfish polymer valve.A chronic animal experiment of Jellyfish valves incorporated into conventional sac-type blood pumps for over 300days exhibited that there were a fracture and calcification on this flexible membrane. Therefore, a long durability (approx. 1 year guarantee) of Jellyfish valve has been developing. while clearing a cause of the problems.First of all, design improvement of Jellyfish valve was attempted. Results of finite element analysis during closed phase of Jellyfish valve indicated that mechanical strain generated on valve membrane fracture and calcification in the animal experiment. Moreover further analysis suggested that an additional circular rim located at 7.0mm in radius was quite effective to avoid strain concentration. In vitro steady and pulsatile tests demonstrated that a modified valve with 0.5mm width rim located at 70mm in radius had a comparable hydrodynamic performance to the original Jellyfish valve.For the next step, commercially available two types of accelerated fatigue tests were employed. Fatigue tests successfully revealed that a durability of the modified valve was much more extended than the original Jellyfish valve by 7 times.Thus, chronic animal experiment with conventional sac-type blood pumps in which the modified valves were incorporated was performed for months. Hemolysis related to the application of the modified valve was not observed. This would be owing to the tapered configuration of the additional rim with 0.1mm width of inflow side.From the data above, the modified polymer valve showed great promise for clinical artificial heart application, and it was also clarified that our prevent fatigue tester could provide comparative durability data of polymer valves

  • Development of a mock circulatory system as a supporting tool to propose the oprimal cardiac surgery

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    An originally-designed mock circulatory system (MCS) has been developed in order to evaluate functions of several types of artificial organs for the surgical treatment of cardiovascular deseases. The features of the present MCS has a capability of exhibiting a practical simulation of hemodynamics in aortic vascular prostheses, and of having a mechanical feasibility of the natural left ventricular contraction by the computer-based control.As mechanical properties of arterial vascular grafts are different from those of elastic natural arteries, it can be speculated that the left ventricular afterload might be elevated after the graft implantation due to its low compliance. By switching blood flow to a bypass graft which was inserted in parallel with the natural descending aorta of dog, the characteristic impedance was elevated by 2.6 times, furthermore, the cardiac output was decreased by 14%, and the cardiac work calculated from the pressure-volume relationships in the left ventricle, was increased by 1.5 times. MCS was also employed to represent hemodynamic characteristics as well as to compare the data with those in animal experiments. When the flow was set to 4L/min in MCS by the mechanical driven pump, either characteristic impedance of the arterial system or external work of the left ventricular model was increased by 2.4 or 1.5 times, respectively. Thus, it was anticipated that the external cardiac work would be elevated by the increase of the arterial impedance after the graft implantation

  • Characteristics of blood sealing for rotary blood pumps

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    A centrifugal blood pump has been developed as an implantable left ventricular assist device. A newly designed mechanical seal with a recirculating cooling water system is used for the shaft seal. The mechanical seal separate cooling water and blood in the sealing face. The objective of this study is to establish the measuring method of bidirectional leakage of the sealed fluid and the cooling-water through the sealing face, especially when blood is as the sealed fluid. The leakage of the blood to the cooling-water side was measured by the atomic emission spectroscopy. The leakage of the cooling-water to the blood side was measured by using the atomic absorption spectroscopy, by using the standard addition method, by the correction of hemolysis caused by leakage of the cooling water. As the results of the experiments, the leakage rate of both the cooling water and the blood were below 0.4[ml/6h]. Therefore, the mechanical seal performed acceptably well to support its use in the centrifugal blood pump

  • Blood sealing properties of mechanical seals for a rotary blood pumps

     View Summary

    The objective of this work is to study the effects of the surface roughness of the sealing face in the mechanical seal for rotary blood pumps on the characteristics of the shaft seal. This mechanical seal is incorporated with a circulating cooling water system for the lubrication, cooling and washing in the sealing face. In this paper, the several types of mechanical seals which have the different surface roughness of Ra=0.009μm, Ra=0.088μm, Ra=0.170μm and Ra=0.250μm were used, and the leakage rate, the torque and the temperature change were measured. The leakage was measured by ion chromatography. The torque was measured by a torque meter and the temperature change was measured by a thermometer which was set in the seat ring. As the results, the torque and the temperature change have the minimum value by using the seat ring of Ra=0.088μm, and the sealed fluid leakage rate has the minimum value of less than 0.1 ml/3h by using the seat ring of Ra=0.009μm

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Presentations

  • Measurements of Frictional Properties of Ni-P-SiC Composite Plating in Water

    Norifumi Miyanaga, Jun Tomioka

    the 2018 International Conference on Engineering Tribology and Applied Technology 

    Presentation date: 2018.11

  • Effects of Flow Properties of Lithium Soap Greases on Bearing Torque

    Norifumi Miyanaga, Mitsumi Nihei, Jun Tomioka

    the 2018 International Conference on Engineering Tribology and Applied Technology 

    Presentation date: 2018.11

  • Measurements of Friction Characteristics of Ni-P-SiC Plating under Water Lubrication

    Norifumi Miyanaga, Shigeaki Minamikawa, Jun Tomioka

    6th Asia International Conference on Tribology (ASIATRIB 2018) 

    Presentation date: 2018.09

  • Influence of Variability of Flow Factors on Lubrication Characteristics of Mechanical Seals

    Jun Tomioka, Mikiko Oyabu, Nakae Yuzawa, Norifumi Miyanaga

    6th Asia International Conference on Tribology (ASIATRIB 2018) 

    Presentation date: 2018.09

  • Stability Analysis of Hydrodynamic Journal Bearings using a Mass-conserving Cavitation Algorithm

    Norifumi Miyanaga, Jun Tomioka

    6th Asia International Conference on Tribology (ASIATRIB 2018) 

    Presentation date: 2018.09

  • Measurements of Hydrodynamic Lubrication Properties on Dimple-type Textured Surfaces

    Norifumi Miyanaga, Terunao Kishida, Jun Tomioka

    6th Asia International Conference on Tribology (ASIATRIB 2018) 

    Presentation date: 2018.09

  • 修正平均流モデルを用いたメカニカルシールの潤滑解析(第2報,歪みと尖りの影響)

    富岡淳, 大籔美貴子, 湯澤央恵, 宮永宜典

    日本設計工学会北陸支部平成30年度研究発表講演会 

    Presentation date: 2018.06

  • 修正平均流モデルを用いたメカニカルシールの潤滑解析(第1報,二乗平均平方根粗さの影響)

    富岡淳, 大籔美貴子, 湯澤央恵, 宮永宜典

    日本設計工学会九州支部,日本図学会九州支部2018年度研究発表講演会 

    Presentation date: 2018.06

  • EFFECTS OF DIMPLE TEXTURE ON HYDRODYNAMIC LUBRICATION OF PARALLEL PLATE BEARINGS

    Norifumi Miyanaga, Terunao Kisida, Jun Tomioka

    The 18th Nordic Symposium on Tribology (NORDTRIB 2018) 

    Presentation date: 2018.06

  • FRICTIONAL PROPERTIES OF NI-P-SIC COMPOSITE COATINGS IN WATER LUBRICATION

    Norifumi Miyanaga, Mitsumi Nihei, Shigeaki Minamikawa, Jun Tomioka

    Presentation date: 2018.06

  • 円筒型スクイーズ軸受の液膜部の粘度およびスクイーズ振動が液膜係数に及ぼす影響

    富岡淳, 橋本涼, 朴成宰, 宮永宜典

    日本設計工学会2018年度春季大会研究発表講演会 

    Presentation date: 2018.05

  • 油潤滑ステップスラスト軸受におけるリンギング現象の発生条件の検討

    富岡淳, 徐沢林, 宮永宜典

    日本設計工学会2018年度春季大会研究発表講演会 

    Presentation date: 2018.05

  • 横振動が気体潤滑ヘリングボーンジャーナル軸受の潤滑特性に及ぼす影響

    富岡淳, 安田有佑, 藤岡正樹, 宮永宜典

    日本設計工学会2018年度春季大会研究発表講演会 

    Presentation date: 2018.05

  • 血液密封用メカニカルシールにおけるクーリングウォータおよび密封溶液の漏れ特性とその潤滑特性

    富岡淳, 宮下和也, 畑中啓輔, 宮永宜典

    日本設計工学会2018年度春季大会研究発表講演会 

    Presentation date: 2018.05

  • Calculations of Bearing Performance by using the Cavitation Algorithm

    Norifumi MIYANAGA, Jun TOMIOKA

    The 4th International Conference on Design Engineering and Science, ICDES 2017 

    Presentation date: 2017.09

  • 強制油膜破断機能付き油潤滑ジャーナル軸受の潤滑特性

    富岡淳, 松岡修史, 大熊勇生, 宮永宜典

    日本設計工学会2017年度春季大会研究発表講演会 

    Presentation date: 2017.06

  • 軸受系の傾斜角度が気体潤滑へリングボーンジャーナル軸受の潤滑特性に及ぼす影響

    富岡淳, 石川雄紀, 湯川達人, 宮永宜典

    日本設計工学会2017年度春季大会研究発表講演会 

    Presentation date: 2017.06

  • 3D-CADによる円筒型スクイーズ軸受装置の装置係数の検討とスクイーズ振動が液膜係数に及ぼす影響

    富岡淳, 田牧祐一, 伊藤僚, 宮永宜典

    日本設計工学会2017年度春季大会研究発表講演会 

    Presentation date: 2017.06

  • 正負両圧力発生機構を持つ溝付きスラスト軸受の潤滑特性

    富岡淳, 御舩剛, 前田和義, 宮永宜典

    日本設計工学会2017年度春季大会研究発表講演会 

    Presentation date: 2017.06

  • 密封血液中の血液抗凝固剤の存在の考慮とクーリングウォータ量を半減させた時のメカニカルシールの潤滑特性

    富岡淳, 栗田悠平, 山本英美, 宮永宜典

    日本設計工学会2017年度春季大会研究発表講演会 

    Presentation date: 2017.06

  • Effect of Acid Washing of SiC Particles on Dispersing and Friction Properties of Ni-P-SiC Composite Plating

    Norifumi MIYANAGA, Shigeaki MINAMIKAWA, Jun TOMIOKA

    the 2016 International Conference on Engineering Tribology and Applied Technology 

    Presentation date: 2016.11

  • Blood Sealing Properties of Magnetic Fluid Shaft Seals

    Jun TOMIOKA, Norifumi MIYANAGA

    the 43th Leeds-Lyon Symposium on Tribology 

    Presentation date: 2016.09

  • ヘリングボーンスラスト気体軸受における溝形状が軸の浮上特性に及ぼす影響

    富岡淳, 神林憲人, 大橋弘明, 宮永宜典

    日本設計工学会2016年度春季大会研究発表講演会 

    Presentation date: 2016.05

  • 円筒型軸受のスクイーズ振動が液膜の状態と液膜係数に及ぼす影響

    富岡淳, 小幡周平, 金子大地, 宮永宜典

    日本設計工学会2016年度春季大会研究発表講演会 

    Presentation date: 2016.05

  • 密封血液のヘマトクリット値がメカニカルシールの潤滑特性に及ぼす影響

    富岡淳, 大籔美貴子, 湯沢央恵, 星野元季, 宮永宜典

    日本設計工学会2016年度春季大会研究発表講演会 

    Presentation date: 2016.05

  • 磁気スラスト軸受で支持されたヘリングボーンジャーナル気体軸受の潤滑特性

    富岡淳, 鳥居尚喜, 森田悠太郎, 宮永宜典

    日本設計工学会2016年度春季大会研究発表講演会 

    Presentation date: 2016.05

  • 油潤滑ジャーナル軸受における給油角度の変化が油膜の状態およびオイルホワール発生に及ぼす影響

    富岡淳, 土居可尚, 田村重典, 宮永宜典

    日本設計工学会2016年度春季大会研究発表講演会 

    Presentation date: 2016.05

  • へリングボーンジャーナル気体軸受の潤滑特性

    鳥居尚喜, 森田悠太郎, 富岡淳

    日本機械学会関東支部関東学生会第55回学生員卒業研究発表講演会 

    Presentation date: 2016.03

  • 溝形状がへリングボーンスラスト気体軸受の浮上特性に及ぼす影響

    神林憲人, 大橋弘明, 富岡淳

    日本機械学会関東支部関東学生会第55回学生員卒業研究発表講演会 

    Presentation date: 2016.03

  • Stability Characteristics of Herringbone-Grooved Aerodynamic Journal Bearings Mounted on Viscoelastic Supports

    Norifumi MIYANAGA, Jun TOMIOKA

    the 42th Leeds-Lyon Symposium on Tribology, Lyon, France 

    Presentation date: 2015.09

  • Stability of Herringbone-Grooved Aerodynamic Journal Bearings Supported by Rubber O-rings

    Norifumi Miyanaga, Jun Tomioka

    International Tribology Conference, TOKYO 2015 

    Presentation date: 2015.09

  • Effects of Hematocrit of the Sealed Blood on the Leakage Characteristics of Blood Cell Component and Plasma Component in a Mechanical Seal

    Jun Tomioka, Mikiko Oyabu, Norifumi Miyanaga

    International Tribology Conference, TOKYO 2015 

    Presentation date: 2015.09

  • Stability Analysis of Herringbone-Grooved Aerodynamic Journal Bearings for Ultra High-Speed Rotations

    Norifumi Miyanaga, Jun Tomioka

    2015 4th International Conference on Advance in Mechanics Engineering (ICAME2015), Madrid, Spain 

    Presentation date: 2015.07

  • エッチングにより溝加工を施した気体潤滑へリングボーンスラスト軸受の浮上特性

    富岡淳, 日野岳要, 鈴木啓扶, 宮永宜典

    日本設計工学会2015年度春季研究発表講演会 

    Presentation date: 2015.05

  • 密封血液のヘマトクリット値がメカニカルシールにおける血球成分および血漿成分の漏れ特性に及ぼす影響

    富岡淳, 大薮美貴子, 荻島和也, 山口亮, 宮永宜典

    日本設計工学会2015年度春季研究発表講演会 

    Presentation date: 2015.05

  • シール面内側と外側の圧力差および圧力和が人工心臓用メカニカルシールの潤滑特性に及ぼす影響

    富岡淳, 大薮美貴子, 福井康平

    日本設計工学会2015年度春季研究発表講演会 

    Presentation date: 2015.05

  • 円筒型軸受のスクイーズ振動が液膜係数に及ぼす影響

    富岡淳, 自見亮佑, 鈴木友寿, 宮永宜典

    日本設計工学会2015年度春季研究発表講演会 

    Presentation date: 2015.05

  • DYNAMIC CHARACTERISTICS OF HERRINGBONE GROOVED AERODYNAMIC JOURNAL BEARINGS WITH VISCOELASTIC SUPPORT

    Jun Tomioka  [Invited]

    The 6th Advanced Forum on Tribology 2015, Wuhan, China 

    Presentation date: 2015.04

  • 血球成分が血液密封下におけるメカニカルシールの漏れ量に及ぼす影響

    富岡淳, 大薮美貴子, 宮永宜典

    日本機械学会北陸信越支部第52期総会・講演会 

    Presentation date: 2015.03

  • しゅう動面における表面粗さ分布の統計的性質がメカニカルシールの潤滑特性に及ぼす影響の理論的検討

    大薮美貴子, 富岡淳

    日本機械学会北陸信越支部第52期総会・講演会 

    Presentation date: 2015.03

  • Dynamic Characteristics of Herringbone Grooved Aerodynamic Journal Bearings with Viscoelastic Support

    Jun TOMIOKA  [Invited]

    2015 Waseda-IITH Joint Workshop (2015年IITHハイデラバード合同ワークショップ) 

    Presentation date: 2015.03

  • 血液密封下のメカニカルシールにおける血漿成分および血球成分の漏れ特性

    富岡淳, 大籔美貴子, 福井康平, 齋藤健斗, 宮永宜典

    トライボロジー会議2014秋盛岡 

    Presentation date: 2014.11

  • 血液密封下のメカニカルシールにおける血漿成分および血球成分の漏れ量測定方法の提案

    富岡淳, 大籔美貴子, 福井康平, 齋藤健斗, 宮永宜典

    日本設計工学会2014年度秋季研究発表講演会 

    Presentation date: 2014.10

  • 平均流モデルを用いたメカニカルシールの潤滑特性解析(第3報,表面粗さ分布における尖りの影響)

    大籔美貴子, 富岡淳

    日本設計工学会2014年度秋季研究発表講演 

    Presentation date: 2014.10

  • Development of Herringbone-Grooved Aerodynamic Journal Bearing Systems for Ultra-High-Speed Rotations

    Norifumi MIYANAGA, Jun TOMIOKA

    2014 Machining, Materials and Mechanical Technology (IC3MT) 

    Presentation date: 2014.09

  • Investigations of Cylindrical and Conical Whirl Instabilities on Hydrodynamic Journal Bearings

    Norifumi MIYANAGA, Jun TOMIOKA

    2014 Machining, Materials and Mechanical Technology (IC3MT) 

    Presentation date: 2014.09

  • An Analysis of the Lubrication Characteristics of Mechanical Seals with Parallel Sealing Faces Using an Average Flow Model

    Mikiko OYABU, Jun TOMIOKA

    2014 Machining, Materials and Mechanical Technology (IC3MT) 

    Presentation date: 2014.09

  • 平均流モデルを用いたメカニカルシールの潤滑特性解析(第2報,表面粗さ分布における歪みの影響)

    大籔美貴子, 富岡淳

    日本設計工学会中国支部講演会 

    Presentation date: 2014.06

  • 軸受支持粘弾性体の温度特性が気体潤滑ヘリングボーンジャーナル軸受の軸受特性に及ぼす影響

    富岡淳, 宮永宜典, 福島正也, 古田育生, 川原立大

    日本設計工学会2014年度春季研究発表講演会 

    Presentation date: 2014.05

  • 油潤滑ジャーナル軸受のシリンドリカルおよびコニカルホワールの同時計測

    富岡淳, 宮永宜典, 田口浩徳, 新井一輝, 森谷安幸

    日本設計工学会2014年度春季研究発表講演会 

    Presentation date: 2014.05

  • 電気伝導計とイオンクロマトグラフィを用いた血液密封用メカニカルシールの密封特性

    富岡淳, 大籔美貴子, 内田恒, 斉藤健斗, 菅野剛史, 宮永宜典

    日本設計工学会2014年度春季研究発表講演会 

    Presentation date: 2014.05

  • 平均流モデルを用いたメカニカルシールの潤滑特性解析(第1報 解析方法の提案)

    大籔美貴子, 富岡淳

    日本設計工学会2014年度春季研究発表講演会 

    Presentation date: 2014.05

  • 赤血球の固定化が血液のレオロジー特性および溶血特性に及ぼす影響

    富岡淳, 大籔美貴子, 稲村健太, 宮永宜典

    日本設計工学会2014年度春季研究発表講演会 

    Presentation date: 2014.05

  • Linear and Nonlinear Stability Analysis of Herringbone-Grooved Aerodynamic Journal Bearings with Viscoelastic Support Elements

    Norifumi Miyanaga, Jun Tomioka

    World Tribology Congress 2013, Torino, Italy 

    Presentation date: 2013.09

  • Stability Analysis of Journal Bearings Lubricated by Viscoelastic Fluids

    Jun Tomioka, Hirotsugu Hayashi, Norifumi Miyanaga

    World Tribology Congress 2013, Torino, Italy 

    Presentation date: 2013.09

  • ジャーナル軸受のシリンドリカルおよびコニカルホワールの同時計測(第2報,理論解析および実験結果との比較)

    富岡淳, 宮永宜典, 高岡洋平

    日本設計工学会北陸支部平成25年度研究発表講演会 

    Presentation date: 2013.06

  • ジャーナル軸受のシリンドリカルおよびコニカルホワールの同時計測(第1報,実験)

    富岡淳, 宮永宜典, 田中翔, 下川宏平

    日本設計工学会中国支部講演会 

    Presentation date: 2013.06

  • メカニカルシールにおける新しい平均流モデルの検討

    大籔美貴子, 富岡淳

    日本設計工学会2013年度春季研究発表講演会 

    Presentation date: 2013.05

  • 粘弾性要素に支持されたヘリングボーン動圧気体軸受の安定性の検討

    宮永宜典, 富岡淳

    日本設計工学会2013年度春季研究発表講演会 

    Presentation date: 2013.05

  • 粘弾性流体で潤滑されたジャーナル軸受の安定解析手法の検討

    富岡淳, 林洋次, 宮永宜典

    日本設計工学会2013年度春季研究発表講演会 

    Presentation date: 2013.05

  • メカニカルシールにおける平均流モデルの提案

    大籔美貴子, 富岡淳

    日本設計工学会四国支部平成24年度研究発表講演会 

    Presentation date: 2013.05

  • 表面粗さの統計学的性質が平均流モデルにおける修正係数に及ぼす影響(第3報,歪みの影響)

    大籔美貴子, 富岡淳

    日本機械学会第20回茨城講演会 

    Presentation date: 2012.08

  • Effects of Statistical Property of Surface Roughness on the Correction Factors in Average Flow Model : 3rd Report, Effects of Skewness

    OYABU Mikiko, TOMIOKA Jun

    日本機械学会第20回茨城講演会 : Ibaraki district conference 

    Presentation date: 2012.08

  • 平均流モデルにおける修正係数に表面粗さの統計学的性質が及ぼす影響

    大籔美貴子, 富岡淳

    日本設計工学会平成24年度春季研究発表講演会 

    Presentation date: 2012.05

  • Effects of Statistical Property of Surface Roughness on the Correction Factors in Average Flow Model(2nd Report, Effects of Kurtosis)

    OYABU Mikiko, TOMIOKA Jun

    日本機械学会東海支部第61期総会講演会 

    Presentation date: 2012.03

  • 表面粗さの統計学的性質が平均流モデルにおける修正係数に及ぼす影響(第1報,自己相関関数の影響)

    大籔美貴子, 富岡淳

    日本機械学会北陸信越支部第49期総会・講演 

    Presentation date: 2012.03

  • Effects of Statistical Property of Surface Roughness on the Correction Factors in Average Flow Model(2nd Report, Effects of Kurtosis)

    OYABU Mikiko, TOMIOKA Jun

    日本機械学会東海支部第61期総会講演会 

    Presentation date: 2012.03

  • Stability Threshold of Herringbone-Grooved Aerodynamic Journal Bearings with Considering Deformation Ratio of Support O-rings

    Norifumi Miyanaga, Jun TOMIOKA

    the international tribology conference Hiroshima 2011 

    Presentation date: 2011.11

  • Evaluating Blood Inflow to the Sealing Face of a Mechanical Seal for Rotary Blood Pumps

    Jun TOMIOKA, Mikiko Oyabu

    the International Tribology Conference Hiroshima 2011 

    Presentation date: 2011.11

  • 粘弾性支持されたヘリングボーン動圧気体軸受のコニカルホワール特性

    宮永宜典, 富岡淳

    日本設計工学会北陸支部平成23年度研究発表会 

    Presentation date: 2011.06

  • 定常流型人工心臓用メカニカルシールのしゅう動面間距離の計測

    富岡淳, 大籔美貴子

    日本設計工学会平成23年度春季研究発表講演会 

    Presentation date: 2011.05

  • 超高速回転体を支持するヘリングボーン動圧気体軸受の温度計測

    宮永宜典, 富岡淳

    日本機械学会関西支部第86期定時総会講演会 

    Presentation date: 2011.03

  • 粘弾性流体潤滑ジャーナル軸受の安定解析

    富岡淳, 林洋次, 宮永宜典

    日本機械学会関西支部第86期定時総会講演会 

    Presentation date: 2011.03

  • 流体膜における二種の溶液の構成が液々分離型メカニカルシールの摩擦特性に及ぼす影響

    富岡淳, 大籔美貴子

    日本機械学会東海支部第60期総会・講演会 

    Presentation date: 2011.03

  • 軸受支持要素の非線形性がヘリングボーン動圧気体軸受の安定性に及ぼす影響

    宮永宜典, 富岡淳

    日本機械学会東海支部第60期総会講演会 

    Presentation date: 2011.03

  • 粘弾性流体で潤滑されたジャーナル軸受の運転安定限界特性(第2報,非線形軌道法を用いた解析)

    富岡淳, 林洋次, 宮永宜典

    日本機械学会東海支部第60期総会講演会 

    Presentation date: 2011.03

  • 軸受支持Oリングのつぶし率がヘリングボーン動圧気体軸受の安定性に及ぼす影響

    宮永宜典, 富岡淳

    日本機械学会北陸信越支部第48期総会・講演会 

    Presentation date: 2011.03

  • 粘弾性流体で潤滑されたジャーナル軸受の運転安定限界特性(第1報,摂動法による解析)

    富岡淳, 林洋次, 宮永宜典

    日本機械学会北陸信越支部第48期総会・講演会 

    Presentation date: 2011.03

  • しゅう動面に二種の溶液が存在するメカニカルシールの摩擦特性に関する実験的検討

    富岡淳, 大籔美貴子

    日本設計工学会東北支部平成22年度研究発表講演会 

    Presentation date: 2010.12

  • 軸受支持Oリングの温度依存性がヘリングボーン動圧気体軸受の安定性に及ぼす影響

    宮永宜典, 富岡淳

    日本設計工学会東北支部平成22年度研究発表講演会 

    Presentation date: 2010.12

  • 非線形軌道法を用いたジャーナル軸受内の安定領域の検討

    富岡淳, 宮永宜典, 牛尾裕一, 三上誠

    日本設計工学会平成22年度春季研究発表講演会 

    Presentation date: 2010.05

  • 外部弾性・減衰要素に支持されたヘリングボーン動圧気体軸受のコニカル安定性

    宮永宜典, 富岡淳

    日本設計工学会平成22年度春季研究発表講演会 

    Presentation date: 2010.05

  • 軸受支持要素の温度特性を考慮したヘリングボーン動圧気体軸受の安定性(第2報,理論的検討)

    宮永宜典, 富岡淳

    日本設計工学会平成22年度春季研究発表講演会 

    Presentation date: 2010.05

  • 軸受支持要素の温度特性を考慮したヘリングボーン動圧気体軸受の安定性(第1報,実験的検討)

    富岡淳, 宮永宜典, 横山真平

    日本設計工学会平成22年度春季研究発表講演会 

    Presentation date: 2010.05

  • 血液シール下におけるメカニカルシールしゅう動面の温度計測

    富岡淳, 宮永宜典, 相馬周平

    日本設計工学会平成22年度春季研究発表講演会 

    Presentation date: 2010.05

  • 表面粗さを考慮したメカニカルシールしゅう動面の潤滑特性

    富岡淳, 大籔美貴子

    日本設計工学会平成22年度春季研究発表講演会 

    Presentation date: 2010.05

▼display all

Specific Research

  • 表面粗さの方向性を考慮した人工心臓用メカニカルシールの血液密封特性の解明

    2020  

     View Summary

    本研究では,血液シール下特有の潤滑特性を解明するために,表面粗さの方向性を考慮した新しい平均流モデルを用いた人工心臓用メカニカルシールの血液密封特性を明らかにし,シールしゅう動面の設計に関する設計指針を得ることを目的とした.具体的には,血液が血球成分と血漿成分から構成されることを考慮した新しい漏れ量測定法の確立を目指すとともに,表面粗さ分布の方向性を考慮した新しい平均流モデルを誘導した.さらに,それに基づく流体潤滑特性解析手法を確立し,人工心臓用メカニカルシールの血液密封特性の解明を目指す.また,理論解析と実験を比較検討することにより,提案した理論の妥当性を検証した.

  • 粘弾性流体に潤滑されたジャーナル軸受けの安定化に関する研究

    2011  

     View Summary

    本研究では,潤滑剤の粘弾性特性がジャーナル軸受の運転安定限界に及ぼす影響について明らかにすることを目的とし,線形マックスウェルモデルに基づく潤滑方程式を誘導した.さらにこの式をジャーナル軸受に適用した.得られた潤滑方程式は圧力の時間微分項を含んでいるため,ジャーナルの微小旋回運動を仮定した摂動法を用いて線形化し,油膜係数を得た.その後,フルビッツの安定判別法を用いて,潤滑油の粘弾性特性がジャーナル軸受の安定運転限界特性に及ぼす影響を検討した.得られた結果を以下に示す.(1)潤滑剤の粘弾性特性は,ジャーナル軸受の線形弾性係数のうち主対角成分であるk1およびk4に影響を及ぼすことがわかった.(2)潤滑剤の粘弾性特性は,ジャーナル軸受の線形減衰係数のうち連成成分であるb2およびb3に影響を及ぼすことがわかった.(3)粘弾性流体潤滑ではニュートン流体潤滑に比べて,偏心率がε<0.3程度で安定領域が広がっており,また,0.3≦ε≦0.7程度では不安定領域が広がることがわかった.(4)軸剛性が小さくなるほど不安定領域が広がる傾向があったが,これらは粘弾性流体潤滑の方がニュートン流体潤滑に比べて顕著であった.(5)軸受幅径比が大きくなるほど粘弾性流体潤滑の影響を受けるため,低偏心率での安定領域の拡大や中偏心率での不安定領域の拡大が顕著であった.(6)一方,マックスウェルモデルに基づくレオロジー方程式を差分化することで数値解析に適した潤滑方程式を誘導した.また,この式を運動方程式とともに直接解くことで粘弾性流体潤滑されたジャーナル軸受の軸心軌跡を計算した.(7)粘弾性流体潤滑の場合,低偏心率域では,ニュートン流体潤滑の場合と比較して安定領域が広がり,速度変数βがより小さくなるまで安定な軸心軌跡が得られた.しかし,中偏心率域では不安定領域が広がるため,ニュートン流体潤滑と比較して速度変数βがより大きな値で軸心軌跡が発散し始めた.このような傾向は,摂動法により得られた安定限界線図とよく一致していた.

  • 血液密封用メカニカルシールのしゅう動面間距離の測定方法の確立

    2010  

     View Summary

    定常流型人工心臓においては血液の軸シールが非常に重要である.そこで,これまで血液密封用メカニカルシールの摩擦と漏れに代表される潤滑特性に関して研究を行ってきた.このメカニカルシールの摩擦,漏れ特性は,しゅう動面間距離と密接に関係しており,メカニカルシールの潤滑特性を明らかにすると同時に,しゅう動面間距離を把握しておくことは重要といえる.しかし定常流型人工心臓における血液密封用メカニカルシールは非常に小さく,またサブマイクロメートル単位の高精度な測定が要求されるため,しゅう動面間距離の測定は困難であり現在まで行われてこなかった.そこで本研究では,これらの問題を解決し,血液密封用メカニカルシールのしゅう動面間距離の測定方法を確立することを目的とした.本研究では,シールリングと一体となった回転軸における軸方向の変位を測定することにより,しゅう動面間距離を間接的に算出することを試みた.回転軸が静止しているとき,シールリングはシートリングに接しているが,回転軸を駆動させるとシールリングの位置は軸方向に移動し,二つの端面の間にすきまが生じる.したがって,このシールリングの変位を測定すれば,しゅう動面間距離に換算することができる.測定の結果,以下の結論を得た.(1)シールリングにおける軸方向の変位を測定することによって,しゅう動面間距離を間接的に算出することができた.(2)しゅう動面におけるすべり速度が大きくなるとともに,しゅう動面間距離は増大した.(3)しゅう動面における密封流体が高粘度であるほど,しゅう動面間距離は増大した.(4)流体潤滑領域では,しゅう動面間距離が増大するとともに摩擦トルクおよび摩擦係数は大きくなる.無次元しゅう動面間距離と摩擦係数のあいだには,累乗関数的な関係がみられた.

  • 最適支持剛性を有するヘリングボーン動圧気体軸受システムの構築

    2009  

     View Summary

    一般に,動圧軸受は高速回転域において自励振動が発生して安定性に乏しいため,超高速回転の実現には外部支持要素の設計が重要であると思われる.しかし,軸受を外部要素によって支持する安定化法は実用レベルで多く利用されているものの,理論的および実験的な詳細な検討は少なく十分でない.そこで,外部弾性・減衰要素で支持されたときのヘリングボーン動圧気体軸受の高速安定性について,理論的,実験的に検討し,さらなる超高速回転体の開発に対する設計指針を得る必要があるものと考えられる.そこで本研究では,外部弾性・減衰要素に粘弾性レオロジーモデルを適用し,その弾性係数および減衰係数をさまざまに変化させ,最適支持剛性を有するヘリングボーン動圧気体軸受システムの構築を目的とした.その結果,以下の結論を得た.(1)軸受を弾性要素のみで支持し,減衰要素を付加させなかった場合,弾性係数が小さくなるほど安定限界が低くなり,軸受を剛体支持したよりも安定性が向上することはない.(2)外部要素の弾性係数が潤滑の剛性に対して大きくなると,外部弾性・減衰要素による軸受支持の効果がほとんど見られない. (3)外部要素と潤滑膜の剛性が比較的近い値になると,安定限界が複雑に変化して外部要素の影響が大きく現れる.このとき,減衰比を0.2から0.6程度に設計することによって,ヘリングボーン動圧気体軸受の運転安定領域を大幅に広げることができ,安定限界を剛体支持された場合に比べて3倍以上にまで高めることができる.(4)外部要素の弾性係数の値が潤滑膜の剛性に対して小さくなると,剛体支持の場合に比べて安定限界を2倍程度まで向上させることが可能である.このとき,減衰比が大きくなるほど安定限界値が大きくなる傾向がある.(5)ヘリングボーン動圧気体軸受を外部要素で支持した場合,一度自励振動が発生しても,さらに高速運転することで自励振動が消滅し,安定運転できる軸受支持条件が存在する.

  • 超高速回転を支えるヘリングボーン動圧気体軸受の開発

    2007  

     View Summary

    超高速回転体の開発は,発電機やコンプレッサ等のターボ機械の超小型化を可能にする.現在,このような超高速回転体の支持軸受には,静圧型の空気軸受が多く用いられている.しかしながら,静圧型の空気軸受では,圧縮空気源などの大掛かりな付帯設備装置を必要とする.そのため,支持軸受として動圧型の軸受を用いた方が,静圧型を用いた場合よりも軸受構造上の利点を生かした小型化が見込めると思われる.その一方で,一般に動圧軸受では,潤滑膜の特性に起因する自励振動によるホワール不安定性のために,超高速回転の実現は大変困難である. そこで本研究では,ホワール不安定性が比較的少ないとされるヘリングボーン動圧気体軸受が超高速回転の実現に有効であることを提案し,開発することを目的とした.そのために,へリングボーン溝形状,軸駆動用タービン,圧縮空気供給用ノズル位置の影響等を検討した.さらに,超高速回転による軸の遠心膨張の影響はかなり大きくなるものと思われる.そこで,解析においては,軸の遠心膨張を考慮し,理論解析には線形法と非線形軌道法を用いた.また,実験を行ない,理論解析結果と比較検討した.その結果,以下の結論を得た.(1) 線形法を用いた検討の結果,遠心膨張を考慮すると,回転数が高くなるにつれて膜厚さが減少して溝の効果が最適化されることによって,遠心膨張を考慮しないときよりも安定性が向上したが,それ以上に回転数が高くなると最適値から遠ざかることにより不安定化した.(2) 非線形軌道法による解析結果は,線形法において安定であった領域の点ではつり合い点に収束,安定限界付近の点ではリミットサイクル,不安定領域の点では発散し,両解析結果はよく一致した.また,両解析から得られた周波数比の値もよく一致した.(3) 実験結果は本解析により得られた値とよく一致しており,遠心膨張を考慮した本研究によって超高速回転を支持するヘリングボーン動圧気体軸受の動特性が明らかになった.

  • 冷却システムを備えた血液ポンプ用メカニカルシールの潤滑特性

    2006  

     View Summary

     冷却システムを備えた血液ポンプ用メカニカルシールの潤滑特性を検討するために,インペラを取り外したシールしゅう動面のみを検討できる実験装置を開発した.それを用いて,しゅう動面での摩擦損失トルク,温度変化,漏れの観点から,人工心臓用メカニカルシールのしゅう動面の表面粗さが軸シール特性に及ぼす影響について検討した.実験には,表面粗さRa=0.009&micro;m,Ra=0.088&micro;mおよびRa=0.170&micro;mの3種類を用いた.得られた結論を以下に示す.(1)Ra=0.009&micro;mのシートリングでは,しゅう動面間が非常に狭くなるため流体摩擦の影響が大きく,摩擦損失トルクおよび温度上昇が大きかった.一方,Ra=0.170&micro;mのシートリングでは,局所的な混合潤滑も影響により,摩擦損失トルクおよび温度上昇が大きくなった.Ra=0.088&micro;mのシートリングでは,すべての実験条件において摩擦トルクが最も小さくなり,トルク特性の観点からみれば現在使用されているRa=0.088&micro;mのシートリングが最も優れていた.(2)シールしゅう動面の温度変化を計測する手法を確立し,しゅう動面の温度特性を検討した結果,温度特性はトルク特性とよく似た傾向を示し,温度変化はRa=0.088&micro;mのシートリングで最も低くなった.また,そのときの温度変化は0.3K以下に抑えられた.よって,温度特性の観点からみれば現在使用されているRa=0.088&micro;mのシートリングが最も優れていた.(3)Ra=0.009&micro;mのシートリングを使用した場合,しゅう動面間が非常に狭くなり,シール面に対して両サイドの圧力差の影響を受けにくくなり,血液漏れ量および血液中へのクーリングウォータの漏れ量をともに少なく抑えることができた.漏れ量は,密封溶液漏れ量,クーリングウォータ漏れ量ともに0.03 ml/3hであった.そのため,漏れ量の観点からは現在使用されているRa=0.088&micro;mのシートリングよりも,Ra=0.009&micro;mのシートリングのほうが優れていた.

  • 定常流型補助人工心臓の軸シールに関する研究

    2003  

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    軸シール部の冷却・洗浄を目的に開発された「Cool-Seal-System」を搭載した定常流型補助人工心臓をさらに小型化・長寿命・高信頼とするためには,血液による摩擦損失トルクの上昇,密封流体およびC.W.(クーリングウォータ)の漏洩の問題を解決する必要がある.そこで,本研究では,定常流型補助人工心臓用メカニカルシールの摺動面粗さに注目し,Ra=0.009,Ra=0.088,Ra=0.170のシートリング,およびRa=0.093のシールリングを用いて,摺動面の表面粗さが人工心臓用メカニカルシールの潤滑特性に及ぼす影響を,トルク特性,密封特性の両観点から調査することを目的とした. メカニカルシールの漏れ量に関しては,血中たんぱく質の影響により血液をそのまま用いての測定が困難なため,血液相当液としてMgCl2水溶液を用い,チャンバ内圧力100[mmHg],回転数3000[rpm],マグネット反発力3.0[N]とし,C.W.側(純水中)に漏れ出したMg元素濃度をイオンクロマトグラフィ-により測定した.トルク特性に関しては,チャンバ内にHt値30%のブタ血液,C.W.に純水を用いて,回転数を1000~8000[rpm],マグネット反発力3.0~5.0[N]に変化させ,摺動面にかかる摩擦損失トルクの大きさを測定した. 実験結果より,シールの漏れ量は摺動面粗さに依存し,粗さの増加とともに漏れ量も増加し,Ra=0.170での漏れ量は約0.16[ml/3h]であった.摩擦損失トルクの最低値は表面粗さが最も大きいRa=0.170で最も低くなり,その大きさは約2.5[mN・m]であった.これにより,定常流型補助人工心臓用メカニカルシールの潤滑特性向上には,摺動面の表面粗さを考慮した設計が重要であることがわかった.

  • 潤滑剤の非線形粘弾性特性がジャーナル軸受の運転安定限界特性に及ぼす影響

    1997  

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    潤滑剤の諸特性を改善するために多量の高分子重合物を添加した潤滑油は、非線形の粘弾性挙動を示すことが知られている。しかし、ジャーナル軸受によって支持された軸の安定性に関する研究は、潤滑剤としてニュートン流体を用いた場合のみで、そのレオロジ方程式の複雑さから粘弾性流体に対する研究はほとんどなされていない。そこで本研究では、粘弾性流体に対する潤滑方程式の解法として微小振動の過程を用いた線形化手法による解析を提案し、潤滑剤の粘弾性特性がジャーナル軸受の運転安定限界特性に及ぼす影響を明らかにすることを目的とする。 本研究では、粘弾性モデルとしてばねとダッシュポットが直列に結合されたマックスウェルモデルを用いる。マックスウェルモデルに対するレオロジ方程式と、連続の条件式、および力の釣り合い条件式を連立させることにより、粘弾性流体に対する潤滑方程式を得る。この潤滑方程式を解くために、ジャーナルの微小振動を仮定し、油膜の弾性係数および粘性係数に対応する微分方程式の誘導を行い、これより油膜係数を算出する。この結果をもとに微小振動時の油膜力を求め、ジャーナルの運動方程式と連立させることによってその特性方程式を求め、これを解くことによりジャーナルの運転安定限界特性を求める。 その結果、潤滑剤の粘弾性特性がジャーナル軸受の安定限界に及ぼす影響として、粘弾性流体ではニュートン流体に比較して、低偏心率では不安定領域が広がり、高偏心率では逆に安定領域が広がるという結論を得た。研究成果の発表1998年5月富岡淳、柴崎健一、折橋健治、林洋次、粘弾性流体で潤滑された有限幅ジャーナル軸受の動特性、平成10年度日本設計工学会春季発表講演会

  • 非線形粘弾性流体で潤滑されたジャーナル軸受の自励振動に関する研究

    1996  

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     近年、高速回転や高荷重など過酷な条件下で使用されている滑り軸受では、潤滑剤の諸特性を改善するために多量の高分子重合物を添加した潤滑油が使用されている。この種の潤滑油は非線形の粘弾性挙動を示すことが知られている。しかし、この非線形粘弾性挙動が、ジャーナル軸受などの滑り軸受において特に問題となる自励振動に及ぼす影響は明らかではない。 そこで本研究では、潤滑剤の非線形粘弾性挙動が、ジャーナル軸受の安定限界曲線およびオイルホワール発生時におけるジャーナルの軸心軌跡に及ぼす影響を明らかにする事を目的とする。 解析において、微小振動の仮定を用いる場合と用いない場合の2とおりを検討し比較した。 まず、微小振動の仮定を用いる場合は、油膜の弾性係数および粘性係数に対応する微分方程式の誘導を行い、これより油膜係数を算出する。この結果をもとに微小振動時の油膜力を求め、ジャーナルの運動方程式と連立させることによって特性方程式を導き、これを解くことにより軸受の安定限界曲線を求めた。 次に、微小振動の仮定を用いない場合は、非線形粘弾性流体に対するレイノルズ方程式を直接解くことにより油膜力を求め、これとジャーナルの運動方程式とを連立させ、時間に関する高次差分法を導入することにより、ジャーナルの軸心軌跡を求め、軸受の安定特性を求めた。 その結果、いずれの解析においても、低偏心率の場合は潤滑剤として粘弾性流体を用いた方がニュートン流体より安定域が増大し、高偏心率の場合は逆の傾向を示すという結論が得られた。

  • 非線形マックスウェル流体で潤滑されたジャーナル軸受の動特性に関する研究

    1995  

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    潤滑剤の諸特性を改善するために多量の高分子重合物を添加した潤滑油は,粘弾性挙動を示すことが知られている。この粘弾性挙動が軸の安定性に及ぼす影響を,理論的に明らかにすることが本研究の目的である。 研究方法としては,粘弾性モデルとして非線形マックスウェルモデルを用い,基礎方程式を流体潤滑理論に適用し潤滑方程式を得て,さらにこれを無限長幅ジャーナル軸受に適用し,非線型偏微分方程式を得る。圧力の線形近似と,軸の微少振動を正弦波と仮定した「近似解法1」,圧力の線形近似を高次の項まで考慮した「近似解法2」の2通りの解き方によりこの方程式を解いて,圧力,油膜力,油膜係数を求める。ここで中央にロータを持ち両端で軸受に支えらている弾性軸の系を考え,その振動方程式から導かれた特性方程式に油膜係数を代入して安定限界線図を求める。 その結果,「近時解法1」から油膜係数について,弾性係数は粘弾性流体の方がニュートン流体よりも高くなり,粘性係数については逆に粘弾性流体の方が低くなった。また安定限界線図から潤滑剤として粘弾性流体を用いると中偏心率では不安定領域が広がり,低偏心率及び高偏心率では逆に安定領域が広がった。「近似解法2」では,近似に次数が低いときには「近似解法1」と同じ結果を得ることが出来たが,高くなると結果が不安定になった。

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