著者

山口 健 那須 大毅

出版者

一般社団法人 日本トライボロジー学会

雑誌

トライボロジスト (ISSN:09151168)

巻号頁・発行日

vol.65, no.7, pp.424-430, 2020-07-15 (Released:2020-07-15)

参考文献数

20

被引用文献数

1

---

The control of slippage between a hand and an object is fundamental to improving athletic performance in sports that require a strong grip, such as baseball and rock-climbing. In order to prevent slippage between a hand and an object, athletes often use grip-enhancing powders to maintain grip in both dry and wet conditions. In baseball pitching, rosin powder, which comprises magnesium carbonate powder and pine resin, is often used as grip-enhancing agent. In this review, the normal force range applied at the finger during ball releasing process in fastball pitching is introduced and the effect of rosin powder application at the finger tip on the frictional characteristics between finger and baseball leather sheet is described. The friction coefficient is not necessarily increased by the presence of rosin powder at the finger pad-leather sheet interface under dry conditions. However, under wet conditions, rosin powder application increases the friction coefficient relative to the nonpowdered condition in the large normal force condition, indicating the efficacy of rosin powder as a grip-enhancing agent.

著者

橋村 真治 小松 恭一 大津 健史 関戸 裕二郎

出版者

一般社団法人 日本トライボロジー学会

雑誌

トライボロジスト (ISSN:09151168)

巻号頁・発行日

vol.62, no.3, pp.205-216, 2017-03-15 (Released:2017-03-16)

参考文献数

12

---

In recent years, self-loosening detail mechanisms of bolted joints had been revealed using three dimensional FE analysis in which the bolts and the nuts have almost perfect configurations geometrically. However the configurations of actual bolts and nuts have certainly errors. Wear on contact surfaces also occurs in the actual bolted joint. Hence it is not easy to accurately simulate the actual bolted joint by only FEM. In this study, an influence of lubricants on self-loosening characteristics have been investigated in order to understand actual phenomena in self-loosening process. The self-loosening tests for a hexagon head cap screw M10 due to transverse vibration were performed under lubricated conditions by Machine oil ISO VG46, Molybdenum disulfide grease and Polyisobuthylene which is used as a special lubricant for bolt tightening. A bearing surface configuration of the bolt was controlled in this study. The results showed that the bolted joints lubricated by Polyisobuthylene had a higher resistance for self-loosening than the bolted joints lubricated by Molybdenum disulfide grease and Machine oil ISO VG46. The number of cycle until loosening depended on bearing surface configurations.

著者

崔 埈豪 日比 貴之 古野 晃久 川口 雅弘 加藤 孝久

出版者

一般社団法人 日本トライボロジー学会

雑誌

トライボロジスト (ISSN:09151168)

巻号頁・発行日

vol.62, no.3, pp.228-235, 2017-03-15 (Released:2017-03-16)

参考文献数

21

被引用文献数

5

---

In our previous study, microstructure and mechanical properties of diamond-like carbon (DLC) films prepared by plasma based ion implantation and deposition using toluene (C7H8) as a source gas were investigated. It was reported that G-peak full width at half maximum [FWHM(G)] shows a maximum value at a G-peak position of around 1540 cm-1, indicating structural changes of DLC films; polymer-like (PLC) to diamond-like carbon (DLC) structure in lower wavenumbers than 1540 cm-1 and diamond-like to graphite-like carbon (GLC) structure in higher wavenumbers than 1540 cm-1. Further, two linear relationship between mechanical properties and FWHM(G) were observed depending on the microstructure of DLC films. In this study, we report the dependence of source gases, methane (CH4), acetylene (C2H2) and toluene, on the microstructure of DLC films, and the correlation between microstructure and mechanical properties of DLC films. It was found that FWHM(G) shows a maximum at a G-peak position of around 1540 cm-1 regardless of source gases. Furthermore, there exists a linear relationship between PL background component and hydrogen content of the films, that is, hydrogen content can be estimated by a simple equation regardless of source gases. The correlation of hardness with FWHM(G) of DLC films prepared using CH4 and C2H2 gas shows good agreement with the correlation line of DLC-GLC provided in the case of C7H8.

著者

小池 亮 鈴木 厚 栗原 和枝 足立 幸志

出版者

一般社団法人 日本トライボロジー学会

雑誌

トライボロジスト (ISSN:09151168)

巻号頁・発行日

vol.64, no.8, pp.504-512, 2019-08-15 (Released:2019-08-15)

参考文献数

21

---

The viscosity of motor oil gets lower in order to decrease resistance at region of the fluid lubrication. On the other hands, this causes increasing of friction at the boundary lubrication region. For this reason, it is required to use a friction modifier to reduce the boundary friction. MoDTC is especially used as friction modifier. Although the decomposition mechanism of MoDTC has been presumed, it is considered only in the case of metal, not hard coatings. So, it is required to understand the effects of hard coatings to friction in motor oils. We tried to clarify the surface and tribo-film changes depending on the kinds of hard coatings by SEM-EDX, TEM and so on. As a result of experiment of hard coatings against metal, we clarified the process as follows when friction of CrN reduces. In the early stage of friction, Fe of the opposite metal transfers to CrN. Mo2S2O2 intermediate product which is formed by MoDTC decomposition is formed on CrN divided into Fe oxide and Mo sulfide. At this time, crystal orientation between Fe oxide and CrN is matching because the lattice constant of Fe oxide is twice that of CrN. These results show that the crystal structure of hard coatings is important for formation of stable interface. And this newly knowledge is necessary to achieve low friction for systems using hard coatings.

著者

鎌本 繁夫 村田 順司 獅子原 祐樹

出版者

一般社団法人 日本トライボロジー学会

雑誌

トライボロジスト (ISSN:09151168)

巻号頁・発行日

vol.64, no.3, pp.186-192, 2019-03-15 (Released:2019-03-15)

参考文献数

12

被引用文献数

4

---

Deep groove ball bearings can support radial load and axial load in both directions and are widely used as bearings for automobiles and industrial machineries because of advantages such as low torque, low noise and low cost. In recent years, the introduction of automobile fuel economy regulation has been advanced worldwide and will be further strengthened in the future. In the field of industrial machinery, energy saving is also progressing. Deep groove ball bearings used in these fields are required to have lower torque. In many cases, deep groove ball bearings are used for grease lubrication and until now low torque has been promoted by improving grease but there is a limit to the reduction of torque with only improvement of grease, we report on the achievement of low torque by developing a cage of new structure without other performance decreasing.

著者

長谷 亜蘭

出版者

一般社団法人 日本トライボロジー学会

雑誌

トライボロジスト (ISSN:09151168)

巻号頁・発行日

vol.68, no.7, pp.446-448, 2023-07-15 (Released:2023-07-15)

参考文献数

25

著者

獅子原 祐樹 長谷 亜蘭

出版者

一般社団法人 日本トライボロジー学会

雑誌

トライボロジスト (ISSN:09151168)

巻号頁・発行日

pp.22-00018, (Released:2023-02-24)

参考文献数

14

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In recent years, sensing technology has been attracting attention in various industrial fields, and the demand for state detection technology of rolling bearings is increasing. An acoustic emission (AE) technique is effective means for state detection of rolling bearings, because it is more sensitive than the conventional technique. In this study, the AE signals generated from tapered roller bearings when seizure occurred due to starved lubrication were investigated. The AE signal changes during the process of reducing lubricating oil were analyzed. The AE frequency spectra were mainly in the frequency range around 0.1 to 0.4 MHz, and the signal strength was increasing during the process of reducing lubricating oil. Before seizure occurred, the AE signal strength in the high frequency around 1.2 MHz was increasing. In addition, surface changes of the tapered roller bearing due to seizure were observed. Based on these results, it became clear that the direct contact of the metal surface corresponds to the AE frequency peak around 0.1 to 0.4 MHz, and the progress of adhesion corresponds to the shift of the centroid frequency to the high frequency side.

著者

小野寺 康 佐藤 優子 佐藤 魁星 渡部 誠也 佐々木 信也

出版者

一般社団法人 日本トライボロジー学会

雑誌

トライボロジスト (ISSN:09151168)

巻号頁・発行日

pp.20-00011, (Released:2020-12-02)

参考文献数

21

---

Friction reduction by engine oil under low temperature as well as high temperature conditions are required because of the increasing number of hybrid vehicles where bulk oil temperature is low. Friction modifier (FM) technology to realize it is required. Friction performance of MoDTC, which works well at high temperature, used with adsorption type friction modifiers, which work well at low temperature, was investigated. Low molecular type, glycerol monooleate (GMO) inhibited friction reduction performance of MoDTC while polymer type FM showed little inhibition. Surface analysis indicated that the reaction film by MoDTC was not existed when the GMO was used together while it existed when it is used with polymer FM (PFM). The cause of the difference was studied by their adsorption performance examined by quartz crystal microbalance. GMO showed high adsorption density, while PFM showed low adsorption density compared to that of MoDTC. The result indicated that GMO competitively adsorbed on the surface, inhibiting the reaction film formation by MoDTC while polymer FM does not. The study indicated that use of the polymer FM with MoDTC is one of the solutions of FM design that works under both high and low temperature.

著者

小野寺 康 佐藤 優子 佐藤 魁星 渡部 誠也 佐々木 信也

出版者

一般社団法人 日本トライボロジー学会

雑誌

トライボロジスト (ISSN:09151168)

巻号頁・発行日

vol.66, no.1, pp.77-85, 2021-01-15 (Released:2021-01-15)

参考文献数

21

---

Friction reduction by engine oil under low temperature as well as high temperature conditions are required because of the increasing number of hybrid vehicles where bulk oil temperature is low. Friction modifier (FM) technology to realize it is required. Friction performance of MoDTC, which works well at high temperature, used with adsorption type friction modifiers, which work well at low temperature, was investigated. Low molecular type, glycerol monooleate (GMO) inhibited friction reduction performance of MoDTC while polymer type FM showed little inhibition. Surface analysis indicated that the reaction film by MoDTC was not existed when the GMO was used together while it existed when it is used with polymer FM (PFM). The cause of the difference was studied by their adsorption performance examined by quartz crystal microbalance. GMO showed high adsorption density, while PFM showed low adsorption density compared to that of MoDTC. The result indicated that GMO competitively adsorbed on the surface, inhibiting the reaction film formation by MoDTC while polymer FM does not. The study indicated that use of the polymer FM with MoDTC is one of the solutions of FM design that works under both high and low temperature.

著者

畠山 望

出版者

一般社団法人 日本トライボロジー学会

雑誌

トライボロジスト (ISSN:09151168)

巻号頁・発行日

vol.64, no.10, pp.614-619, 2019-10-15 (Released:2019-10-15)

参考文献数

15

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Ski wax plays an important role to improve the skiing performance. The following three functions are required for the high-performance wax: high water-repellency, low friction, and high durability. Fluorinated waxes have high water-repellent and low frictional properties; however, they are less durable. Therefore, first the high affinity paraffin is waxed to a ski running surface (ski sole) made of ultra-high molecular weight polyethylene, then the fluorinated paraffin is over-waxed, by using a hot iron. Each wax performance especially depends on the temperature, thus the accurate measurements have been made to evaluate the absolute temperature at the interface between sole and snow during skiing. As a result, the temperature increase due to frictional heating actually depended on the type of wax.

著者

長谷 亜蘭

出版者

一般社団法人 日本トライボロジー学会

雑誌

トライボロジスト (ISSN:09151168)

巻号頁・発行日

vol.67, no.4, pp.263-269, 2022-04-15 (Released:2022-04-15)

参考文献数

12

---

Using a novel educational method that incorporates problem-solving game activity into science and engineering education, the author is energetically performing educational activities for children and young people who will bear the next generation. Even in the new normal life, which is a lifestyle change caused by COVID-19 in recent years, it is important to continue to provide children with educational opportunities to come into contact with science and engineering. By promoting online educational practices using the developed teaching materials, it is possible to convey the importance and fun of science and engineering to more children, not just in limited areas. This article introduces the newly developed online teaching materials and the results obtained through the execution of the events, and describes the advantages and problems of implementing the educational method.

著者

田邉 幸子 佐々木 信也

出版者

一般社団法人 日本トライボロジー学会

雑誌

トライボロジスト (ISSN:09151168)

巻号頁・発行日

vol.62, no.11, pp.711-717, 2017-11-15 (Released:2017-11-15)

参考文献数

21

---

There has been concern about anisotropic wear properties of UV-LIGA (Ultraviolet-Lithographie, Galvanoformung,Abformung) processed Ni. The depositing direction in the electroplating process, which is one of the UV-LIGA processes,could cause anisotropic crystalline structure. The purpose of this study is to investigate anisotropic wear phenomena of the UV-LIGA processed Ni. The wear mechanism was discussed from the standpoints of crystalline structure based on the wear behavior obtained from sliding tests. Experimental results showed the difference in wear between the horizontal and vertical plane to the plane of depositing. It is considered that the crystalline shape which appeared on the sliding planes affects the wear properties. By the addition of the gloss agent to the electroplating bath, there was significant improvement in the wear property with no anisotropic finer crystalline and higher hardness.

著者

渡邉 保奈美 小野寺 康 佐藤 魁星 川田 将平 佐々木 信也

出版者

一般社団法人 日本トライボロジー学会

雑誌

トライボロジスト (ISSN:09151168)

巻号頁・発行日

vol.67, no.3, pp.191-200, 2022-03-15 (Released:2022-03-15)

参考文献数

20

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Ionic liquids containing halogens have good lubricity, however, they are reported to cause corrosive wear. In contrast, halogen-free ionic liquids do not cause such corrosive wear, but they do not have good lubricity comparable to the halogen-containing counterparts. In this study, we focused on specific halogen-free boron-containing ionic liquids that exhibited low friction performance. The performance was mainly due to its boron-containing anions, because it was realized with both phosphonium-based and ammonium-based cations. Surface analysis and scratch test with atomic force microscope (AFM) were conducted with phosphonium-based cations to clarify the low friction mechanism. The boron-containing ionic liquid, [BOB][P66614], showed lower friction of around 0.01, which was much lower than MoDTC-containing engine oils did. The cause of the ultra-low friction with [BOB] [P66614] is thought to be due to the fact that the reaction film formed by friction has a very smooth surface and suppresses contact between metals. On the other hand, another boron-containing ionic liquid [BMB] [P66614], which did not form a smooth surface, showed relatively high friction compared to [BOB] [P66614]. Scratch tests with AFM indicated that the softer reaction film derived from [BOB] [P66614] led to the formation of a smooth sliding surface.

著者

野老山 貴行 梅原 徳次

出版者

一般社団法人 日本トライボロジー学会

雑誌

トライボロジスト (ISSN:09151168)

巻号頁・発行日

vol.65, no.4, pp.236-241, 2020-04-15 (Released:2020-04-15)

参考文献数

18

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From time immemorial, shaving one’s beard has been continued. Using razor or electric shaver is common for all male adult to show their cleanliness recently. The custom for shaving my beard by myself was harbingered by World War I and II. Tremendous safety razors were provided by US government to frontline infantry, then they acquired a custom of “shaving by myself”. An electric shaver was invented early of the 20th century, and it is divided two shaving motion, a rotation or a reciprocation. In this article, investigating the relation between inner blade’s edge radiuses and pulling force, clarifying differences of shaving mechanism of a rotation or a reciprocation type shaver by a high speed camera with measuring pulling force simultaneously are explained.

著者

山田 義智

出版者

一般社団法人 日本トライボロジー学会

雑誌

トライボロジスト (ISSN:09151168)

巻号頁・発行日

vol.67, no.1, pp.14-21, 2022

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<p>This paper first outlines the rheological model used for flow analysis of fresh concrete that has not yet hardened. Next, the classification of the flow analysis method for fresh concrete is shown, and examples of analysis by the MPS method, which the authors have been working on in recent years, is described. Finally, I would like to describe the expectations and prospects for the rheology of fresh concrete.</p>

著者

渡邉 保奈美 小野寺 康 佐藤 魁星 川田 将平 佐々木 信也

出版者

一般社団法人 日本トライボロジー学会

雑誌

トライボロジスト (ISSN:09151168)

巻号頁・発行日

pp.21-00014, (Released:2022-01-12)

参考文献数

20

---

Ionic liquids containing halogens have good lubricity, however, they are reported to cause corrosive wear. In contrast, halogen-free ionic liquids do not cause such corrosive wear, but they do not have good lubricity comparable to the halogen-containing counterparts. In this study, we focused on specific halogen-free boron-containing ionic liquids that exhibited low friction performance. The performance was mainly due to its boron-containing anions, because it was realized with both phosphonium-based and ammonium-based cations. Surface analysis and scratch test with atomic force microscope (AFM) were conducted with phosphonium-based cations to clarify the low friction mechanism. The boron-containing ionic liquid, [BOB][P66614], showed lower friction of around 0.01, which was much lower than MoDTC-containing engine oils did. The cause of the ultra-low friction with [BOB] [P66614] is thought to be due to the fact that the reaction film formed by friction has a very smooth surface and suppresses contact between metals. On the other hand, another boron-containing ionic liquid [BMB] [P66614], which did not form a smooth surface, showed relatively high friction compared to [BOB] [P66614]. Scratch tests with AFM indicated that the softer reaction film derived from [BOB] [P66614] led to the formation of a smooth sliding surface.

著者

蟹 拓実 野老山 貴行 梅原 徳次 村島 基之 李 義永 八木下 和宏

出版者

一般社団法人 日本トライボロジー学会

雑誌

トライボロジスト (ISSN:09151168)

巻号頁・発行日

vol.66, no.7, pp.570-578, 2021-07-15 (Released:2021-07-15)

参考文献数

40

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In general, several mechanical parts are subjected to friction and wear. To prevent wear and high friction coefficient under lubrication, additives can work to reduce friction force, to build up thin film on surfaces which is so-called tribofilm. Recently, Diamond-Like Carbon (DLC) is focused because it has excellent low friction and high wear proof as solid lubricant. However, several researchers already reported that tetrahedral amorphous carbon (ta-C) showed abnormal wear when it rubbed with glycerol mono-oleate (GMO) that is a kind of additive, although it showed very low friction coefficient. To improve tribological properties, new additives were developed that had both phosphate-oxide structure derived from ZnDTP which had high wear resistance and hydroxyl group derived from GMO in one structure. To clarify the effects of the additives, friction tests were performed fixed-roller-on-disk type rotating friction tester. In the friction tests, hydrogenated amorphous carbon (a-C:H) disks, and a-C:H coated rollers were used under boundary lubrication condition at 20-80°C. Friction tests were conducted in Poly-α-olefin (PAO) oil with each GMO and the additives. The results exhibited that a-C:H gave ultra-low friction with the additive. Elemental analysis of the surface showed that tribofilm of phosphorus and oxygen was detected on the a-C:H surface in the additive used condition.

著者

小西 智也 小野寺 康 田中 宏昌 杉村 丈一

出版者

一般社団法人 日本トライボロジー学会

雑誌

トライボロジスト (ISSN:09151168)

巻号頁・発行日

pp.21-00010, (Released:2021-09-17)

参考文献数

20

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Smoothing surface roughness by the use of additives is one of the promising approaches to reduce friction loss and wear under boundary lubrication. Effect of phosphorus anti-wear agents on controlling surface roughness is focused in this study. Zinc dithiophosphate (ZnDTP), generally used as an anti-wear agent for engine oil, formed rough surface by forming inhomogeneous phosphorus and sulfur films. In contrast, a particular neutral phosphorus agent that reduced surface roughness and prevented wear was found, which forms homogeneous phosphoric acid film. An acidic phosphorus agent also reduced surface roughness and reduced friction and promote low shear stress molybdenum disulfide film formation with Molybdenum dithiocarbamate (MoDTC), but it was accompanied with a large amount of wear. Use of the neutral and the acid phosphorus agents together realized low friction, reduced wear, and very smooth surface by forming reaction films composed of sulfur and phosphorus type films. The study indicates that forming a homogeneous phosphoric film of low shear strength by the use of specific phosphorous agents is one of a promising approach to establish and sustainable boundary film of low friction and low wear.

著者

酒井 健一 高橋 拓夢 松枝 宏尚 砂川 和輝 宇野 円蔵 坂田 浩 赤松 允顕 酒井 秀樹

出版者

一般社団法人 日本トライボロジー学会

雑誌

トライボロジスト (ISSN:09151168)

巻号頁・発行日

pp.21-00017, (Released:2021-10-30)

参考文献数

15

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We characterized the adsorption and desorption behavior of a sulfur-type extreme-pressure (EP) agent in a mixture of dodecane and methyl oleate (MO) as a model polar oil. The solid material used in this study was iron oxide or steel. The quartz crystal microbalance with dissipation monitoring technique revealed that the residual mass of the EP agent, measured after rinsing the adsorption film by dodecane or the mixture of dodecane and MO, was smaller in the mixed oil than in dodecane. This indicates the lesser adsorption ability of the EP agent in the mixed oil, resulting from the facts that (i) the solubility of the EP agent in the mixed oil is larger than that in dodecane, and (ii) the competitive adsorption between the EP agent and MO occurs on the iron oxide surface. We also analyzed the surface composition of the steel substrate, followed by thermal treatment of the adsorption film. The addition of MO required higher temperatures to yield a reaction film of the EP agent. Although the residual mass of the EP agent in the mixed oil was smaller than that in dodecane, no significant difference in a lubrication ability was observed between the two reaction films.

著者

中村 健太 村木 正芳 中津 賢治

出版者

一般社団法人 日本トライボロジー学会

雑誌

トライボロジスト (ISSN:09151168)

巻号頁・発行日

vol.66, no.3, pp.220-228, 2021-03-15 (Released:2021-03-15)

参考文献数

14

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Influence of alkyl group of primary zinc dialkyldithiophosphate (ZDDP) on the friction and wear properties was studied using two different kinds of ZDDPs under the boundary lubrication condition with a pin-on-disk type tribotester. A coefficient of friction (COF) was determined under the following three operating conditions: the constant condition, the step-load condition and the variable-speed condition. COF of linear-alkyl ZDDP showed lower value than that of branched-alkyl ZDDP under all these conditions. Nano-friction force of the tribofilm obtained in the constant condition test was measured by means of an atomic force microscope. Meanwhile, nano-friction force ratio of the branched type to the linear type was almost same as COF ratio. It was suggested that macro-scale frictional behaviour was governed by nano-scale mutual interaction of tribofilms. On the other hand, the wear scar diameter decreased with increasing ZDDP concentration. From the energy dispersive X-ray spectroscopy analysis, the wear scar diameter was inversely correlated with phosphorus concentration on the worn surface. These results suggested that COF depended on mechanical properties of top layer of tribofilm while wear resistance depended on the thickness of base layer of tribofilm containing polyphosphate.