岡山大学 工学部 機械工学科

機械設計学研究室

研究年報（2001 年 1 月〜12 月）＊＊研究課題＊＊
高真空用歯車のトライボ性能評価
Tribological Evaluation of Surface Modified Gear in Vacuum

表面改質ローラの高真空トライボロジー特性
Tribological Characteristics of Surface Modified Roller in High Vacuum

高機能材料の高温トライボロジー
Tribological Characteristics of High Functional Materials

改質表面の真空高温摩擦・摩耗特性
Friction and Wear Characteristics of Modified Surface for Space and Air Crafts in Vacuum and at
High Temperature

表面改質材のトライボロジーとその評価・解析
Tribology of Surface Modified Materials and Its Estimation and Analysis

軟質コーティングによるピッチング強さの改善
Improvement of Pitting Durability by Soft Coatingショットピーニング粉末焼結歯車の疲れ強さと動的性能
Fatigue Strength and Dynamic Performance of Shot-peened Sintered Powder Metal Gears

複合表面処理歯車の面圧強さ
Surface Durability of Multiplex Surface Treated Gears

粉末焼結ローラの面圧強さに関する研究
A Study on Surface Durability of Sintered Powder Metal Rollers

浸炭硬化ローラの面圧強さに及ぼすショットピーニングの影響
Effect of Shot Peening on Surface Durability of Case-Hardened Rollers

制振合金歯車の面圧強さと動的性能
Surface Durability and Dynamic Performance of Damping Alloy Gears

多孔質ファインセラミックス製静圧ガイドに関する研究
A Study on Hydrostatic Guide Made of Porous Fine Ceramics＊＊研究報告＊＊（9 件）
Tribological Behaviors of Multiplex Plated Stainless Steel Rollers in High Vacuum
Akira YOSHIDA, Masahiro FUJII and Tomoki HARANO* (*Anan National College of Technology)
Proceedings of the International Tribology Conference Nagasaki 2000, Vol.II, pp.1421-1426, 2001
Two-cylinder test was carried out under non-lubricating condition in high vacuum to investigate thewear and friction behavior of electroless Ni plating and multiplex plating based on electroless Ni-P
alloy plating. Ni-P alloy plating (Ni-P), two kinds of multiplex plating, that is Ni-P with PTFE
particles (Ni-P+PTFE) and Ni-P with BN particles, were employed. The initial friction coefficient of
Ni-P plating roller with φ0.2µm PTFE particles was the smallest in all test rollers. The friction
behavior of Ni-B plated roller was the most stable in all test rollers and so, the surface profile was
the smallest. In case that the elastic modulus of plated layer is smaller than that of substrate, thecalculated shear stress in plated layer has the maximum value at the position near the boundary
between the substrate and the layer without frictional force. The calculated shear stress around aPTFE particle was larger than that around a BN particle in the plated layer.

Fatigue Life Assessment of Surface Hardened Sintered Rolling under Sliding-Rolling Contact
Condition
Akira YOSHIDA, Yuji OHUE*, Masanori SEKI (*Kagawa University)
Proceedings of the International Conference on Mechanical Transmissions ICMT2001, pp.472-477,
April 2001
To assess the surface durability of sintered machine elements, the fatigue lives of 28 kinds ofsintered rollers under a sliding-rolling contact condition were estimated by using the Paris's law
based on the fracture mechanics. The fatigue tests were conducted using two cylinders testingmachines. The stress intensity factor for the mode II under a condition of Hertzian contact wascalculated using FEM. The value of the stress intensity factor became larger as the crack lengthand the pore size became longer. It could be clarified that the fatigue lives of the sintered rollersdepended on the pore diameter, the distance between pores and its hardness. It was important totake the pore distribution into consideration to assess the fatigue lives of the sintered rollers.

耐摩耗性鋼および表面改質処理材のスカッフィング特性
三浦健藏*，薦田哲男*，桑田隆司*，吉田彰，藤井正浩(*三井造船（株））

日本マリンエンジニアリング学会誌，36 巻 4 号，31 頁〜37 頁，2001 年 4 月
機械摺動部材の高強度化，耐久性向上および信頼性向上を目的に，耐摩耗性と耐スカッフィング性を改良した低合金鋼(WRS)を開発した．本研究では，二円筒によるスカッフィング試験を行い，WRS のスカッフィング強さと損傷形態を調べた．WRS は自己潤滑性を有し，従来鋼に比べ良好な耐スカッフィング性を示した．WRS の耐スカッフィング性は硬さに依存し，低硬度の場合に耐スカッフィング性は高く摩擦係数は低かった．Ni-P めっき材の耐スカッフィング性は高かったが，試験初期に浸硫層が消失する浸硫処理のスカッフィング特性は母材のそれと等しかった．スカッフィング発生により表面改質処
理材母材の表面に 30〜50µm の厚さで白層を生じた．この白層は，熱的エネルギーと機械的エネルギーによって表面近傍のセメンタイトの一部が固溶し，炭素が過飽和固溶したマルテンサイトと考えられた．

イオン窒化粉末焼結ローラの面圧強さに関する研究（粉末粒子径の影響ならびに面圧強さと硬さの関係）
吉田彰，大上祐司*，關

正憲，荒瀧拓之**，烏野勇***（*香川大学，**(株)永谷園，***住友金属工業（株））
日本機械学会論文集（C 編），67 巻 658 号，1993 頁〜1999 頁，2001 年 6 月
イオン窒化粉末焼結ローラの面圧強さに及ぼす粉末粒子径と，表面硬化粉末焼結ローラの面圧強さと硬さの関係について報告している．粉末粒子径が小なるほど，その面圧強さはより高くなる傾向にあった．
損傷形態はスポーリング損傷であり，その損傷深さは硬さに対するせん断応力の比の振幅A(τyz/HV)が最大となる深さとほぼ一致した．その最大となる深さでの振幅について，焼結材における面圧強さにおけるせん断応力と硬さの関係を調べたところ，気孔分布が同じであれば，面圧強さと硬さはほぼ比例関係にあるが，気孔分布が異なると，硬さによって面圧強さを一義的に決められないことを明らかにした．

Study of Optimum Disperased Particle Size for Wear of Multiplex Plated Surfaces
Akira YOSHIDA, Masahiro FUJII and R.S.Dwyer-Joyce* (*University of Sheffield, UK)
Abstracts of Papers 2nd World Tribology Congress WTC2001, p.521, September 2001
Twin-disk tests were carried out under non-lubricating conditions in high vacuum to investigate thewear and friction behaviour of multiplex platings based on electroless Ni-P alloy. Two kinds ofmultiplex plating, which are the Ni-P plating with PTFE particles and the Ni-P plating with BNparticles, were employed. The wear rate of both plated layers with BN particles and with PTFE
particles increased with increasing content of dispersed particles. The wear rate of the layer withPTFE particles was greater than that with BN particles. The influence of elastic modulus andradius of dispersed particles on stresses in the plated layer was investigated with FEM analysis.
The maximum values of Mises stress and maximum shear stress in the plated layer increased withincreasing friction coefficient, with increasing particle content and with decreasing elastic modulusof particles. The radius of the dispersed particles hardly influenced the maximum values of Mises
stress and maximum shear stress in the plated layer. The wear behaviour obtained in theexperiment could be well explained by the calculated stress field.

プラズマ浸炭硬化粉末焼結ローラの面圧強さに関する研究（面圧強さに及ぼすショットピーニング投射速度と投射時間の影響）
吉田彰，大上祐司*，關

正憲，荒瀧拓之**，烏野勇***（*香川大学，**(株)永谷園，***住友金属工業（株））
日本機械学会論文集（C 編），67 巻 661 号，2961 頁〜2968 頁，2001 年 9 月
粉末焼結ローラにプラズマ浸炭とショットピーニングを施し，そのローラを試験ローラとして二円筒滑り転がり接触条件下で疲れ試験を行い，ローラの面圧強さとショットピーニングの影響について検討した．ショットピーニングによりローラ表面付近の硬さと圧縮残留応力が増大したが，ローラ表面付近の気孔がつぶれ，表面粗さが増加した．疲れ試験による試験ローラの損傷はスポーリング損傷が主体であり，気孔がつぶれた場所で損傷が発生していた．さらに硬さに対する両振りの直交せん断応力の比の振幅が最大となるローラ円周面からの深さと損傷深さとがほぼ一致していることを示した．

Effect of Shot Peening on Surface Durability of Plasma Case-Hardened Sintered Powder MetalRollers
Akira YOSHIDA, Yuji OHUE* and Masanori SEKI (*Kagawa University)
Proceedings of the JSME International Conference on Motion and Power Transmissions
MPT2001-Fukuoka, Vol.I, pp.193-198, November 2001
The machine elements of sintered powder metals are generally cheaper than those of steels, while
the machine elements of sintered powder metals have a disadvantage in fatigue strength. Therefore,
the purpose of this study is to investigate the influence of shot peening on surface durability ofsintered powder metal rollers under a sliding-rolling contact condition. The test rollers with 30 mm
and 60 mm in diameter were made of partially alloyed powders which were compacted and sintered.
After a finishing grinding the surface treatments of the test rollers were plasma case hardening andshot peening. The shot peening conditions differed in shot velocity, shot diameter, shot hardness
and peening time. The compressive residual stress, the hardness and the surface roughness of allrollers increased and the pores near the surface of those were deformed by the shot peening.
However, in the case of the test rollers with 60 mm in diameter, the pores not only in near by thesurface but also at the depth of about 2000µm were deformed by the hard shot peenings. The
surface durabilities of the only mild shot-peened rollers with 60 mm in diameter were higher thanthat of the unpeened roller in these experiments. The failure mode of the rollers was mainlyspalling. The spalling cracks propagated from the sharp notches of the pores deformed by the shot

peening. A further important point is that the failure depth agreed almost with the depth where theamplitude A(τyz/HV) of the ratio of the orthogonal shear stress to Vickers hardness becamemaximum. It can be considered that the shear stress below the contact surface of the shot-peenedrollers increases, since the increase of the surface roughness by the shot peening results into theincrease of the frictional force between the rollers. Therefore, the result of this study clearly showsthat the mild shot peening without sharp deformed pore and too large surface roughness should beselected in order to improve the surface durability of the sintered rollers.

Observation of Crack Propagation Behavior in Steel Roller under Sliding-Rolling Contact for
Evaluating Its Fatigue Life
Akira YOSHIDA, Yuji OHUE* and Masanori SEKI (*Kagawa University)
Proceedings of the JSME International Conference on Motion and Power Transmissions
MPT2001-Fukuoka, Vol.I, pp.211-216, November 2001
In order to assess the sliding-rolling contact fatigue lives of surface-hardened sintered rollers fromthe view point of linear fracture mechanics, the crack propagation behavior was investigated undera sliding-rolling contact condition. The surface-hardened rollers which have three kinds of artificial
defects were fatigue tested, and the crack propagation rate was measured. The stress intensity
factor was calculated using the finite element method. The crack propagated from the hole wasalmost parallel to the roller surface. Therefore, it could be said that the crack propagation under asliding-rolling contact condition was in the mode II. The parameters m and C in Paris's law wereobtained from this experiment. Using those parameters, the fatigue lives of the surface hardened
sintered roller were estimated. The estimated fatigue lives were almost the same as theexperimental ones. The fatigue lives of the sintered rollers depend mainly on the pore distribution
and the hardness. It could be considered that the cracks of the sintered rollers occurred from manymean pores and propagated from one pore to another pore.

Effect of Surface Modified Layer on Rolling Fatigue StrengthAkira YOSHIDA and Masahiro FUJII
Proceedings of the JSME International Conference on Motion and Power Transmissions
MPT2001-Fukuoka, Vol.I, pp.249-254, November 2001
Surface modified rollers and ball bearings were fatigue-tested under pure rolling contact conditions.
Electroless Ni-P alloy plating and sulfurizing treatments were employed. Failure mode of all rollers
and bearings was spalling/flaking due to subsurface cracking. Fatigue lives of both rollers andbearings were improved by surface modifications. The influence of elastic modulus of a plated layer
on contact pressure and subsurface stresses was examined under line contact and point contact
conditions. The contact pressure and subsurface stresses were reduced by the soft surface modified
layer, especially at the edge of the contact width under the line contact condition. The conformity
due to wear of the plated layer led to the reduction of the contact pressure and the subsurface

stresses. The reason why the rolling fatigue strengths of surface modified rollers and bearings werehigher than those of the non-coated ones would be due to the smaller contact pressure and thesmaller subsurface stresses by the smaller elasticity as well as the conformity of the plated layer.

＊＊学術講演＊＊（18 件）
Masahiro FUJII
Influence of Surface Modification on Rolling Contact Fatigue Strength
Tribology at Twelve, University of Sheffield

吉田彰，大上祐司*，関2001.2.2

正憲，川崎俊彦（*香川大学）

滑り・転がり接触条件下のき裂伝ぱ挙動の観察
日本機械学会中国四国支部第 39 期総会・講演会講演論文集，No.015-1，講演番号 901，311 頁-312 頁
2001.3.6

吉田彰，大上祐司*，関正憲，後藤田佳和（*香川大学）

ショットピーニングローラの面圧強さに関する研究
日本機械学会中国四国支部第 39 期総会・講演会講演論文集，No.015-1，講演番号 902，313 頁-314 頁
2001.3.6

吉田彰，藤井正浩，柳井寛之輔

フラクタル次元による改質表面の摩耗過程の評価
日本機械学会中国四国支部第 39 期総会・講演会講演論文集，No.015-1，講演番号 907，323 頁-324 頁
2001.3.6

吉田彰，藤井正浩，上路嘉隆

粒子分散複合めっき層の強度に及ぼす粒子の影響に関する解析的研究
日本機械学会中国四国支部第 39 期総会・講演会講演論文集，No.015-1，講演番号 908，325 頁-326 頁
2001.3.6

吉田彰，藤井正浩，堀口清司

耐摩耗性ステンレス鋼の焼付きおよび摩耗特性
日本機械学会中国四国支部第 39 期総会・講演会講演論文集，No.015-1，講演番号 909，327 頁-328 頁
2001.3.6

吉田彰，大上祐司*，關

正憲，藤永宏**（*香川大学，**鐘淵化学工業(株)）浸炭硬化鋼製ローラの面圧強さに及ぼすショットピーニングの影響
日本機械学会第１回機素潤滑設計部門講演会・講演論文集，No.01-11，講演番号 213，81 頁-84 頁
2001.4.3

Akira YOSHIDA, Yuji OHUE, Masanori SEKI (*Kagawa University)
Fatigue Life Assessment of Surface Hardened Sintered Rolling under Sliding-Rolling ContactCondition
Proceedings of the International Conference on Mechanical Transmissions ICMT2001, pp.472-477
2001.4.5

吉田彰，大上祐司*，關

正憲，佐藤雅靖（*香川大学）

ショットピーニング粉末焼結歯車の面圧強さと動的性能
日本機械学会 2001 年度年次大会・講演論文集(Ⅲ), No.01-1, 講演番号 F-0332，165 頁-166 頁

2001.8.30

Akira YOSHIDA and Masahiro FUJII
Study of Optimum Disperased Particle Size for Wear of Multiplex Plated Surfaces
Abstracts of Papers 2nd World Tribology Congress WTC2001, pp.521

吉田2001.9.6

彰，藤井正浩，岡内健

Ni 系めっき表面の真空・高温摩擦摩耗特性
日本設計工学会平成 13 年度秋季研究発表講演会講演論文集，講演番号 21，69 頁-72 頁

吉田彰，大上祐司*，関正憲，川村2001.9.29

巧（*香川大学）

ショットピーニング鋼製歯車の面圧強さと動的性能
日本設計工学会平成 13 年度秋季研究発表講演会講演論文集，講演番号 30，101 頁-104 頁

2001.9.29

藤井正浩
粒子分散複合めっき層の強度に及ぼす分散粒子径の影響について
中国四国機素潤滑設計技術研究会

吉田彰，大上祐司*，關

2001.11.9

正憲（*香川大学）

滑り転がり接触条件下における鋼製ローラのき裂進展挙動
日本トライボロジー学会トライボロジー会議予稿集宇都宮，講演番号 3D14，447 頁-448 頁

2001.11.8

Akira YOSHIDA, Yuji OHUE* and Masanori SEKI (*Kagawa University)
Effect of Shot Peening on Surface Durability of Plasma Case-Hardened Sintered Powder MetalRollers
Proceedings of The JSME International Conference on Motion and Power Transmissions
MPT2001-Fukuoka, Vol.I, pp.193-198

2001.11.15

Akira YOSHIDA, Yuji OHUE* and Masanori SEKI (*Kagawa University)
Observation of Crack Propagation Behavior in Steel Roller under Sliding-Rolling Contact for
Evaluating Its Fatigue Life
Proceedings of The JSME International Conference on Motion and Power Transmissions
MPT2001-Fukuoka, Vol.I, pp.211-216

2001.11.15

Akira YOSHIDA and Masahiro FUJII
Effect of Surface Modified Layer on Rolling Fatigue Strength
Proceedings of The JSME International Conference on Motion and Power Transmissions
MPT2001-Fukuoka, Vol.I, pp.249-254

吉田2001.11.17

彰

歯車の材料と熱処理講習会「最新の機器設計に必要な歯車技術の基礎から応用まで（基礎編）」教材，日本機械学会，pp.35-42
2001.12.21＊＊総説・解説＊＊（1 件）
歯車への導入吉田彰

トライボロジスト，46 巻 4 号，43 頁〜44 頁，2001 年 4 月
トライボロジスト（日本トライボロジー学会）の特集号：リファレンス

オブリファレンスで，これから歯車の研究に着手する若手研究者のために，基礎となる教科書，解説書，専門書，代表的論文，最新情報等の紹介および解説を行った．

＊＊特許＊＊（1 件）

歯車動的性能の評価システム及び評価手法
吉田彰，大上祐司，本郷俊明

公開特許広報出願）

特開 2001-242009，平成 13 年 9 月 7 日公開，
（特願 2000-54298，平成 12 年 2 月 29 日