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Tsutomu NAKANISHI, Shogo NISHIMUTA, Takuya YAMAMOTO, Gang DENG
Article type: Article
Session ID: S1103-1-4
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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Tooth surface-finishing method using the plasticity material was developed to improve the production efficiency and obtain the high surface durability of automotive power transmission gears. In the plasticity material, the volcanic-ashes, oil clay and mineral oil were mixed together. First, the test gear tooth was finished by plasticity material which flowed on the tooth surface. Secondly, the surface of test gear tooth was investigated using a scanning electron microscopy and a surface texture measuring instrument. From these experiments, the following results are obtained: By applying the designed tooth surface-finishing method to the shaved and case-carburized gear tooth, the mark of the shaving almost disappears. The asperity on the tooth surface becomes smooth. The absolute value of surface roughness decreases with the increase of the operating distance. Therefore, it is found that the tooth surface-finishing method have advantageous process from the viewpoint of resource saving, energy saving and environmental protection.
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Shinji HASHIMURA, Kodai IMAMURA, Hirofumi Kage, Genyu TANAKA
Article type: Article
Session ID: S1103-1-5
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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Run-out of hob arbor directly and grealty influences a gear accuracy which was cut by it. Hence it is very important for tightgening a hob arbor to reduce occurence of run-out. A new tightening method which can drastically reduce the run-out has been proposed in this study. To verify the usefulness of the proposed method a new tightening device was developed, and tightening experiments were performed using the developed device. The results showed that the run-out was reduced using the developed device drastically within about 5 μm.
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Takayoshi ITAGAKI, Hideo TAKAHASHI, Hiroshi IIZUKA, Tatsuya ITO
Article type: Article
Session ID: S1103-2-1
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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The injection-molded-plastic-gears are used in such many fields as home electric appliances, information processing equipments, audio-visual equipments, automobiles and so on. In this study, For the test gears, the injection molded plastic spur gears were used. The test gears are made from two types of plastic. One of these plastics is polyacetal (POM), and the other one is the plastic filled with rice-hull-silica-carbon (RHSC) as reinforcing materials. The RHSC is one of natural materials, and the polyacetal (POM) is used as standard plastics. The experimental results showed that the RHSC has a beneficial effect on the filler of plastic. Based on the experimental results, the effect of the RHSC were discussed. From the discussions, it seems reasonable to conclude: (1) The sound pressure of meshing frequency at the plastic gear is reduced by the RHSC. (2) The noise due to the slide on the tooth surface decreases as compared with a general plastic gear.
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Hideo TAKAHASHI, Takayoshi ITAGAKI, Hiroshi IIZUKA, Kaoru MIZUTA
Article type: Article
Session ID: S1103-2-2
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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The injection-molded-plastic-gears are used in such many fields as home electric appliances, information processing equipments, audio-visual equipments, automobiles and so on. Many factors have an effect on load carrying characteristics of an injection-molded-plastic-gear pair. Among others, the materials and the temperature of plastics are the most important factors, because the plastic physical property is greatly different in each plastics type, and the high temperature causes the decrease in Young's modulus of plastic. Therefore, the plastic gears are mixed with the reinforcing materials, which are glass fibers, chemical fibers, polytetrafluoroethylene, and graphite for keeping strength even in high temperature. On the other hand, natural materials are used to focus on the ecological recycling. The rice hull is a residual product of rice and its amount is about 2.6 million tons per year in Japan. Based on the above background, the authors focused on using a rice-hull-silica-carbon (RHSC) with a reinforcing material in plastics. In this study, the strength of the plastic filled RHSC gears was compared with the polyacetal (POM) gears. As a result, the effects of new plastics as gear materials were observed.
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Mikio TAKAHASHI, Hideo TAKAHASHI, Takao KOIDE
Article type: Article
Session ID: S1103-2-3
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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Load carrying capacity of the crossed helical gears is considered to be low since the theoretical meshing is of a point contact. However, there is a possibility that a comparatively strong power can be transmitted because the contact area is widened by the elastic deformation and wear of gear teeth. In this study, the load carrying characteristics of the plastic (polyacetal co-polymer) crossed helical gears were investigated. The endurance tests for the plastic crossed helical gears of helix angle of 20 degrees were performed. Temperatures of meshing teeth and atmospheric temperature were measured during operation and the fatigue life of gear teeth was determined. As a result, the relation between the life of gears and temperature of meshing teeth was clarified. And the relation between temperature rise from atmospheric temperature of meshing teeth and PV value was clarified.
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Keiji KATANO, Hiroyuki KIMURA, Takashi TAMURA, Akira IWABUCHI, Tomohar ...
Article type: Article
Session ID: S1103-2-4
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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We studied on reducing backrush in no-loading and investigated on the factors affecting the in loading for 3K-type Paradox gear reducer. The gear reducer is composed plastic micro gears. In no loading, backrush is reduced by changing in the transportation coefficient for planet gears. In loading, backrush of this reducer grows lager with loading value, and backrush in no-loading is much smaller than that of in loading. The principal factors of backrush in loading are clearance between carrier and two internal gears, and transformation of rotary internal gear.
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Kouitsu MIYACHIKA, Makoto KUSAKABE, Hideaki KATANUMA, Hidefumi MADA
Article type: Article
Session ID: S1103-3-1
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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This paper presents a study on hardened layer and bending fatigue strength of induction-hardened gears. The measurement of hardened layer and the bending fatigue test were carried out for induction hardened gears made of thermally refined, as-rolled and normalized S35C and S45C steels, and then the surface hardness, the hardened depth, the macro- and micro-structure of hardened layer and S-N curves were obtained. Effects of the pre-treatment and the tempering on the bending fatigue strength of induction hardened gears were examined.
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Kouitsu MIYACHIKA, Shinji KAYAMA, Takao KOIDE, Hidefumi MADA
Article type: Article
Session ID: S1103-3-2
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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This paper describes a study on effects of case depth, face width, gear-side carburizing and interglanular oxidation on bending fatigue strength of case-carburized spur gears. Bending fatigue tests of case-carburized gears with different case depths, face widths, carburized parts and carburizing methods (gas and vacuum carburizing) were carried out, and then S-N curves were obtained. Effects of the case depth, the face width, the carburized part and the intergranular oxidation on the bending fatigue strength of case-carburized gears were examined.
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Takao KOIDE, Hatsuhiko USAMI, Kouitsu MIYACHIKA, Koji TSUBOKURA
Article type: Article
Session ID: S1103-3-3
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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This paper describes the bending fatigue strength of fine particle bombarded (FPB) gears. Thermally refined S45C gears and case-carburized SCM415 gears were shot-peened by different shot materials of various diameters. Bending fatigue tests for these gears were performed using a pulsator. The effects of shot materials and shot diameters of FPB on the bending fatigue strength of gears were determined. Bending fatigue strengths of thermally refined S45C gears and case-carburized SCM415 gears are found to become larger by about 10〜40% with FPB.
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Masatoshi YOSHIZAKI
Article type: Article
Session ID: S1103-3-4
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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Carburized gears with tooth surfaces in different states were prepared by changing surface treatments, and gear surface fatigue endurance tests were carried out to clarify the influence of running-in performance on the tooth surface strength. Furthermore the relation between the running-in ability and the surface properties was discussed.
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Ruiyun ZHENG, Susumu MATSUMOTO, Hiroyuki SONOBE, Fumio INAYOSHI
Article type: Article
Session ID: S1103-3-5
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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The prognosis for elastic ring breakage of planetary roller type traction drive was investigated. The FFT analysis, the Fractal analysis and the Mahalanobis-Taguchi-Method were used for analysis of torque and vibration signals with operation. The thrice pre-signals were detected by using the M-T Method before the final breakage. The result shows that the M-T Method becomes a useful method for prognosis.
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Kiyoshi OKURA, Yuji MARUYAMA
Article type: Article
Session ID: S1103-4-1
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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It was already reported that the performance of a frictional power transmission belt such as flat or V-ribbed belts can be analytically predicted by using μV characteristics and the results well coincide with the measured ones. The prediction method gives performance proportional to initial tension, while measured one reaches the limit as initial tension goes higher. In this report it is shown that the difference between theoretical and measured performance is caused by the dependence of friction coefficients on tension.
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Kazuki OKUDA, Hirofumi SENTOKU, Ayumi ONO, Yuki HIWATASHI
Article type: Article
Session ID: S1103-4-2
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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Harmonic drive gearing is not researched so much, and the characteristic of load transmission has not been explained. Therefore, the characteristic of load transmission in the harmonic drive gearing is hoped for the improvement of reliability and durability by clarification. In the present study, the measurement of the strain was enabled by using a comparatively large-scale harmonic drive gearing. As a result, a useful result for the clarification of the characteristic of load transmission, stress concentration position such as specification and affected of torque, was obtained.
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Kazuteru NAGAMURA, Kiyotaka IKEJO, Yushiro TACHIBANA, Toshiyuki MATSUK ...
Article type: Article
Session ID: S1103-4-3
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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In this study, we investigated on the vibration of two elliptical gear pairs, which are a single elliptical gear and a double elliptical gear. The circumferential vibration acceleration, the torque variation, and the gear sound pressure level of two elliptical gear pairs and two circular gear pairs with the same number of teeth and the same center distance as the elliptical gear pairs were measured by the running test. Additionally, we developed a torsional vibration model of the testing machine with elliptical gears, and calculated the circumferential vibration acceleration of the test gears, and the torque variation of the test gear shaft. We considered on the vibration of elliptical gears by comparing the measured data with the calculated results.
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Shigeki MATSUMURA, Haruo HOUJOH, Toshiya NAGUMO
Article type: Article
Session ID: S1103-4-4
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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We had already reported estimation method of gear mesh excitation wave form with vibration measurement results to utilize for quality check of manufactured gear system. But it remains an unknown quantity and the exact mesh excitation wave form can't be estimated. In this paper, we propose improved estimation method which supplements frequency response function under low speed range with simulation and it makes possible to give the origine of phase. Proposed estimation method is applied for single stage parallel shaft helical gear reducer.
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Shinji HASHIMURA, Kyoichi KOMATSU, Ryohei ISHIMARU, Yuki ARAMAKI, Tais ...
Article type: Article
Session ID: S1104-1-1
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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The re-tightening method is used in order to check whether the bolted joint was sufficiently tightened or not. However, characteristics of the re-tightening method were not sufficiently investigated. Therefore the behavior of retightening process of a bolted joint must be revealed. In this study, we have investigated behaviors of re-tightening torque in the re-tightening process of a bolted joint focusing on the lubricated condition. The experiments were performed using three lubricants, machine oil ISO VG46, MoS2 grease and a special lubricant for bolt tightening stabilization BTS, were used. The results showed that the re-tightening torque depends on the lubricant. Scatter band of the retightening torques for BTS was the smallest of all.
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Manabu OKADA, Tomonari TSUCHIDA, Satoshi NAKATSUKA
Article type: Article
Session ID: S1104-1-2
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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It is known by past researches on the loosening of a screw that rotation of loosen will arise if the radius direction vibration is given to a bolt head or the bearing surface of a nut. On the other hand, it is known that it is effective in ultrasonic vibration reducing apparent friction, and the method of performing screw tightening with little variation is also studied, it is performed by tightening with the ultrasonic vibration of the direction of the axis to a bolt head or a nut. In this research, the bolt head or the nut was fastened with radial ultrasonic vibration, and it is investigated about the effect.
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Susumu KUMAKURA, Yasumasa SHOJI, Hironao TAKAHASHI, Makori MATSUNAGA
Article type: Article
Session ID: S1104-1-3
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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Generally, bolts and nuts in bolted pipe flange assembly have been tightened using torque wrenches. On the other hand, recently, impact wrenches have been applied for tightening assemblies from working efficiency stand point In the use of the impact wrenches, since the value of tightening coefficient is bigger, it is necessary to take account the value of tightening coefficient when bolts and nuts in important bolted joints are tightened. In the present study, tightening method of nuts and bolts in bolted pipe flange joints is examined when impact wrench is used from FEM calculations and experiments. In this study, with an electric impact wrench, we performed the tightening experiment of the comparatively small size pipe flange, and FEM analysis was carried out for examining the axial tension characteristic. As a result, it is demonstrated that the scatter in bolt tightening forces using impact wrenches can be controlled as the same as that tightened using torque wrenches when the impact wrenches used is selected adequately and their tightening method is correct.
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Susumu KUMAKURA, Yusuke SAKAI, Kazuhiro TAKAHASHI
Article type: Article
Session ID: S1104-1-4
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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Recently, the prevailing torque type nuts have been widely developed and used in bolted joints for preventing self-loosening. Thus, the standards on prevailing torque type nuts have been specified in JIS. However, only few researches have been reported on the loosening mechanism of the prevailing torque type nuts under repeated tensile loads. The effects of the anti-loosening is not elucidated. In this paper, experiments were carried out to measure the self-loosening of bolted joints with four types prevailing torque-type-nuts under repeated tensile loads. As the result, the bolted joint using the biggest nut shows the best performance for preventing the self-loosening compared with the bolted joints using thread calking type of the nut of which the deformation is the biggest, moderate and smaller.
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Susumu KUMAKURA, Yasumasa SHOJI, Tetsuya HAGIWARA
Article type: Article
Session ID: S1104-1-5
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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A lot of researches have been carried out on the self-loosening of bolt under transverse vibration. The cause of loosening due to nut rotation in bolt-nutjoints is the spiral shape of screw thread. In the present study, the objective of the paper is to eluciade the loosening mechanism. In boltedjoints, friction torque occurs at screw thread and the bearing surfaces. In this paper, the effect of the friction torque on the loosening is examined. Firstly, the effect of magnitude of these friction torque on the loosening is examined, and loosening mechanism is discussed according to the behaviors of the joint using FEM calculations.
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Yohei SUZUKI, Shuji HOSOKAWA
Article type: Article
Session ID: S1104-1-6
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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When the external force acts repeatedly, the bolted joint will sometimes loosen. So the accident is caused. For this reason, many researches of loosening of the thread joint have been done for many years. However, it seems that it still is not fully clear about the mechanism loosening of the thread joint by bending repeatedly. In the present study, the rotary bending loosening examination machine is made, it experiments using nominal bolt and nut diameter, M8. The results are that the bolted joint loosens by bending repeatedly and is influencing by rotary direction. However, when the clamp force is large, loosening is small, and the influence of bending moment and rotary direction become small, too.
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Hirohito MATSUOKA, Shinji KASEI
Article type: Article
Session ID: S1104-2-1
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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Few investigations have ever been carried out on this subject. The purpose of this report is to obtain basic information about this problem. The experiments basing the method of the transverse vibration type, in which M3 screws are employed as the test samples, are done up to 50Hz using a device driven by AC servo motor which was newly constructed for this study. Some experiments about the machine screws of different materials are carried out. Experiment results show that the difference of materials of screws influence the loosening characteristics.
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KENJI FUKUDA, SHIGERU YAMANAKA, GENKI HIBI, KOJIRO MORIOKA, YORINOBU T ...
Article type: Article
Session ID: S1104-2-2
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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Magnesium alloys are generally characterized by low thermal resistance, especially by the poor creep resistance. 9Al-Zn-2Ca Magnesium alloy bolt was developed to improve the mechanical properties for the purpose of fastening Magnesium parts mainly used in the transportation industry. Fastening Mg parts with Mg alloy bolts contribute to avoiding bolt loosening due to creep deformation of fastened Mg parts, which is observed in the case of being tightened by steel bolts. In this study, the creep properties of the single bolt are measured and then the Mg bolt-Mg parts-Mg nut system were experimented to investigate the influence of thermal history on the axial force in the bolt. Finite element analysis was executed to explain the bolt loosening mechanism of fastening Mg parts. Steel bolt was employed to compare the mechanism with Mg alloy bolt.
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Genki Hibi, Shigeru Yamanaka, Shuji Hosokawa
Article type: Article
Session ID: S1104-2-3
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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High strength Magnesium alloy bolt by using wrought 9Al-Zn-2Ca alloy was developed for the purpose of fastening the Magnesium parts used in the transportation industry. In the application of vehicles, both fatigue and loosening properties of the bolt are critical due to the vibration loading subjected to the bolts. In this study, we focused on the loosening properties of Mg bolt after its fatigue test in comparison with ordinal steel bolt. The experimental results reveal Mg bolt has higher resistance against bolt loosening than ordinal steels, which is also supported by theoretical review.
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Hitoshi TODA, Shinji HASHIMURA
Article type: Article
Session ID: S1104-2-4
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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Taper nuts , spherical nuts and flange nuts are using for automotive wheels. However, it is considered that the nut configuration has a great influence on mechanical characteristic of the bolted joint. The influence of the nut configuration on the mechanical characteristics of its bolted joint was not investigated so far. Hence, influence of the nut configuration on transverse fatigue strength has been investigated in this study. In the experiment, transverse fatigue tests were performed using taper nuts and flange nuts. The results showed that apparent fatigue strength of the bolted joint with the taper nut was lower than that of the bolted joint with the flange nut.
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Akihiro FURUKAWA, Masaya HAGIWARA
Article type: Article
Session ID: S1104-2-5
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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A hypothesis was presented concerning the effect of the axial residual stress at the first thread root of a bolt on its fatigue strength. However, this has not yet been verified since the residual stress which may exist locally around the thread root cannot be measured or estimated with sufficient accuracy. This study aims to clarify the relationship between the residual stress and the fatigue strength quantitatively. In this report, the residual stress which can be estimated by FE analysis is induced by preloading on the thread root of lead-less (axisymmetrical) bolt quenched and tempered after thread-rolled. The results from fatigue tests in low mean stress condition (Rs = 0.1) show that the preloaded specimens have higher fatigue strength than non-preloaded specimens. However, the effect of residual stress is much smaller than estimated by the hypothesis, and this might be caused by the stress concentration, which cannot be taken into account by axisymmetrical FE analysis due to the construction of threaded adapter.
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Michihiko TANAKA
Article type: Article
Session ID: G1100-1-1
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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Accelerometers are typical examples of piezoelectric elements applying the piezoelectric effect that causes a charge production by applying inertia force on them. Despite the advances of piezoelectric devices and materials in the field of electronics engineering, of decisive importance for piezoelectric effect has not been correctly understood in some branch of mechanical engineering. Especially ,accelerometer is wrongly misused for the unfit purpose,"Innocent misapprehension of jerk, the rate at which acceleration changes". The nature of the piezoelectric effect is closely related to the occurrence of electric charge and a voltage at electrodes. The best-known application is the piezoelectric accelerometer, but direct detection of acceleration variations in the form of jerk is the most unreasonable sensor application. The author will discuss the principles of piezoelectric element using the equivalent of electric circuit from a view point of designing machine elements.
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Taisuke Isida, Shigeo Kotake, Yasuyuki Suzuki
Article type: Article
Session ID: G1100-1-2
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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We have developed new micro surface processing techniques of Si by local anodic oxidation by chemical etching through silicon oil with water at the interface. After drawing micrometer-order SiO_2 mask thin film, line pattern more than 1 μm height at the Si surface was obtained through wet etching in KOH solution. The thickness of the mask film is estimated to be about 6 nm. In addition, we found that this process can be applicable for visualizing the trace of stick-slip vibration on Si.
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Tadashi Honda
Article type: Article
Session ID: G1100-1-3
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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Stellite is the hard-facing material specified in AWS as CoCr-A. The alloy has the good anti-corrosion, anti-wear and anti-erosion properties. Therefore, the alloy is generally used as the valve's seat materials on the pipe-line of the plants. Stellite are used to be welded by gas-welding. Recently, there are tendency to adopt TIG or PTA welding methods. By these methods, iron-dilutions occur due to the un-proper welding conditions. This study has been done to clarify the effects of iron to the sliding properties of the alloy. The allowable iron contents are discussed to obtain the good pressure tightness of the gate valve.
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Toshiharu KAZAMA, Kento KUMAGAI, Yukihito NARITA
Article type: Article
Session ID: G1100-1-4
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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Focusing on geometrical effects of nozzle outlets and jet-impinging surfaces, the experiment on cavitation erosion was conducted. Three types of nozzle holders and three different height of cylindrical walls or thickness of spacers were prepared; for nine combination the geometrical conditions around the submerged cavitating jet were examined. Tap water was used as the test liquid and the temperature was kept at 40-C. The upstream pressure was specified at 10.1 MPa and the downstream was at 0.2 MPa. The specimens of 15 mm in diameter were made of aluminum alloy. The time evolution of mass loss and cross-sectional profiles of the specimens were measured every 15 min, 30 min or 1 hour. The erosion rates were calculated and the maximum rates were compared. The erosion was minimized at the condition of combination of the nozzle outlets and the specimen surfaces which caused less erosion.
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Ying ZHENG, Hiroshi YAMAMOTO
Article type: Article
Session ID: G1100-1-5
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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In this paper, the characteristics of rotating accuracy of hydrostatic gas journal bearing are analyzed theoretically with special attention to the relation with the machining errors of the bearing system. The features and magnitudes of loci of the shaft are discussed in relation to lobe numbers of form deviation of the shaft cross section and feeding hole numbers.. The effect of shaft roundness on the bearing characteristics are discussed. Moreover the rotating accuracy of hydrostatic gas journal bearing with circumferential groove is also investigated. The obtained results may establish fundamental concept of precision design of the hydrostatic gas journal bearing with respect to the rotating accuracy of the shaft.
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Satoshi ONOE, Tomohiko ISE, Toshihiko ASAMI
Article type: Article
Session ID: G1100-1-6
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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Divided type φ6 herringbone grooved journal gas bearings have been developed to support high rotational speed practical rotor for a micro rotary machines such as a palmtop gas turbine generator. Critical mass of a rotor and radial clearance of journal and thrust bearings are designed to rotate over 800,000 rpm. Test journal bearings have radial clearance of 8 μm and mass of 4.2 gram. Roundness under the processed and the reassembled condition of the test radial bearing was measured by using 3-D CMM and was compared to verify repeatability of assembling bearing parts. The precision by reassembled condition was obtained 3.5 μm. Test of this bearings were carried out using a test rig. Spectra under the rotation and the orbit were measured by using displacement meter. Maximum rotor speed exceeded 804,000 rpm and the stably orbit was obtained.
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Kiyoshi HATAKENAKA, Daisuke KONDO
Article type: Article
Session ID: G1100-2-1
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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Floating bush journal bearings are widely used to support small-sized high-speed rotating machinery. In the previous report, the authors have developed an analytical tool to predict the bush rotational speed and stability threshold speed of a rotating shaft that is supported in the bearings. However the predictions were in poor agreement with the measurements. In this report, the tool is modified extensively so as to model the shaft by means of a finite element method and also to obtain the bearing characteristics with the effect of circumferential oil supplying grooves in both inner and outer clearances of floating bush and so on considered. As a result, the predictions agree relatively well with the measurements.
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Takahiro SATO, Tomonobu TAKAHASHI, Yuta SUNAMI, Masayuki OCHIAI, Hirom ...
Article type: Article
Session ID: G1100-2-2
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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In the manufacturing process of miniaturized fluid film bearings, the manufacturing errors of groove affects to the characteristics of the bearings. Therefore, it is necessary to improve the productivity, robust characteristic and ease of manufacture. This paper describes the investigation of optimum design of fluid film thrust bearings to reduce the variability of the characteristics caused by manufacturing errors, hi the optimum design considering productivity, errors were given using probability theory with restriction towards the dynamic stiffness variability. From the results, the reduction of dynamic stiffness variability was accomplished. Furthermore, even with the manufacturing error, the bearing is safely operated without seizures since it is still in the range of the allowable film thickness.
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Morimasa NAKAMURA, Hiromi KODAMA, Ken-ichi MIURA, Kei DEMIZU, Ichiro M ...
Article type: Article
Session ID: G1100-2-3
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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A DLC (Diamond Like Carbon) film is one of the carbon-based hard films having low friction coefficient and high wear resistance. For applying to machine elements under high contact pressure, however, DLC films are required to have better mechanical properties. In the present paper, six kinds of DLC films including Cr/C gradient interlayer were deposited by UBM sputtering method in which substrate bias voltage was changing. And rolling contact tests were performed under contact pressure 2.84GPa, and tribological properties of these films were examined. It was found that friction coefficients of films were unstable when sliding contact occurred together, and fractures in their Cr/C gradient interlayers were observed. Estimating of mechanical properties of the interlayer using nanoindentation test, hardness and Young's modulus of the interlayer increased. However, they decreased less than 0.09μm depth. There change was thought to cause the fracture in the interlayer by rolling contact.
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Ichiro MORIWAKI, Shintaro WATANABE, Ryutaro SHINOHARA, Morimasa NAKAMU ...
Article type: Article
Session ID: G1100-2-4
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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The present paper describes reduction of noise and vibration using plastic gears with metal core under severe operating conditions. Running tests were carried out for plastic gears with metal core under the conditions such as target applied torque of 20Nm, rotation speed of 5000 min^<-1>, and temperature of 373K. Plastic gear with a metal core showed lower sound pressure levels than those having mono structure. In case of a special type of plastic gear, noise and vibration increased drastically when meshing cycles exceed a criterion. Non-destructive tests were performed to reveal defects such as delamination.
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Yasuhisa HATTORI, Yusuke KATO
Article type: Article
Session ID: G1100-2-5
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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In this report an evaluating method for sliding stability of wet clutch subjected to vibratory load, where the stability is represented as dynamic response of friction force to sliding velocity, is proposed. Applying this method to the frictional vibration tester fitted with wet friction material, the situation became more unstable with the exciting frequency decreased. Then stability of the tester was examined by another method: measuring stability limit velocity under the test condition that gradient of friction force-sliding velocity curve changes continuously. Results by two methods were the same in the point that damping caused by the reason except the gradient became smaller for lower frequency, and by the fact validity of the proposed method was confirmed.
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Yutaka TANAKA, Yuichi SHIGA, Hiroyuki GOTO, Hiroshi TAKEDA
Article type: Article
Session ID: S1102-1-1
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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This paper describes the design, analysis and performance of a rotational type of tripod parallel mechanism. The new parallel mechanism has three legs rotating on ground. In order to evaluate motion of the mechanism, we designed a simulator to calculate the motion of the mechanism and analyze the performance of the mechanism by repeated calculatioa The analytical results show that the rotational type of tripod parallel mechanism has larger motion space and angle than the Stewart platform type of parallel mechanism.
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Hiroyuki GOTO, Yutaka TANAKA, Hiroyuki NIHASHI
Article type: Article
Session ID: S1102-1-2
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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This paper reports a novel system of multi-axial materials testing. The system can be applied to testing on advanced composite materials and components that are difficult to evaluate using conventional testing machines, we also propose a method to multi-axial materials testing. The proposed system consists of a testing machine, a measuring instrument and a controller. To realize accurate and practical evaluation for the advanced materials, the testing machine is driven by a parallel kinematics (PKM) structure. Making use of the PKM serves not only to achieve complete motions along six axis but also to obtain high dynamical performance.
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Takaaki OIWA, Kazuki TERADA, Junichi ASAMA, Motohiro SATOU
Article type: Article
Session ID: S1102-1-3
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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This study proposes a kinematic calibration method for a six-degree-of-freedom parallel kinematic machine (PKM), which is based on the polynomial approximation. Several kinematic parameters have a difficulty to be accurately identified because such parameters have a little effect on the motion errors of the end effector. In this report, polynomial equations approximating positioning error of each active prismatic joint substitute for the kinematic parameters. In the simulation, motion errors of the end effector were derived from the kinematic parameters' errors. After that, the least square method using Jacobian matrix corrected coefficients of the polynomial equations so that the motion errors were minimized. Obtained coefficients decreased the motion errors from 2mm to 0.05mm.
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Kazuhisa TAKAHASHI, Sadatomo KURIBAYASHI, Hidenori KOMATSUBARA, Tatsuy ...
Article type: Article
Session ID: S1101-1-1
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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Recently, the research and the development of the technology to use energy effectively are done. However, a part of the steam generated with the boiler of the ship is thrown away without being used. Up to date, there was no effective solution that used such low-pressure steam. Therefore, the energy saving is expected in the ship in using the energy of low-pressure steam. In this report, the prototype steam engine that utilizes low-pressure steam is developed. In addition, this steam engine uses new cam that is called crown cam. Firstly, operating principle of prototype steam engine is described. Secondly, the design specification of prototype steam engine is described. Finally, structure of mechanism of prototype steam engine is shown.
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Jun NANGO, Keisuke YOKOSAWA, Ryosuke KATO
Article type: Article
Session ID: S1101-1-2
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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The walk training make the rehabilitants feel pain because they have to support their body with hands or legs when they use the gait training device. The walker which can motivate the rehabilitants to train is expected to be developed. In this research, we design and develop the walker with the assist equipment translating the artificial walking motion to the rotating wheel motion. Using this walker, the rehabilitants are supported by the saddle, so their hands and legs are relieved from pain keeping their body balance. The assist equipments are designed by using of 6-link planar mechanism, which is the sliding and rotating motion transfer. By method of measuring the pedal reaction force, the load of user is estimated.
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Masanori SEKI, Ichiro SHIMIZU, Masahiro FUJII, Takafumi MATSUI
Article type: Article
Session ID: S1101-1-3
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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Rotary to linear conversion is one of important mechanisms and has been widely used in various mechanical systems. We designed a new mechanism for rotary to linear conversion, which can provide linear output mechanically by using both screws and gears, and will be adequate for the both accurate positioning and high capacity. In this study, the compact mechanism designed for retrofit into mechanical devices was manufactured in order to investigate its fundamental performance. In the positioning accuracy test, the positioning accuracy of this mechanism was superior to that of a feed screw employed a precision ball screw. In the load output test, the load output of this mechanism was larger than that of a precision ball screw under some input torque condition.
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Takashi Tanabe, Kenshi USHIJIMA, Makoto KOBAYASHI, Wataru ARAI, Tsunam ...
Article type: Article
Session ID: S1101-1-4
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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We have been researching an engine system that has multiple-link mechanism between the piston and crankshaft in reciprocating engine to improve the fuel consumption performance. A press fitting at both ends bearing is important for establishment of multiple-link mechanism because of the requirement of compactness. For this reason, it is necessity to improve the performance of anti-seizure. In this report we focused on Mixed, Elasto-hydrodynamic lubrication considering dynamic behavior of multiple-link in working by inputting a moment load and found that it is important for the performance of anti-seizure to reduce the moment load being attributed to the torsional resonance of crankshaft.
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Hirotsugu HAYASHI
Article type: Article
Session ID: S1105-1-1
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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It is purpose in this paper to investigate dynamic oil film observation in thrust squeeze bearings because it is important to make clear boundary conditions in journal bearings under dynamic loads. After an of oil film rupture is demonstrated, the behaviors of cavities and bubbles are discussed by using two high speed video cameras.
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Toshihiro OZASA, Kouichi YORIZANE
Article type: Article
Session ID: S1105-1-2
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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An experimental apparatus of journal bearings for rotor vibration was used in this study. A rotor, composed of a shaft, a weight, one piece of a clutch and a slight disk having many slits for pulse generation, was supported by a pair of journal bearings. The rotor was rotated by an electric motor and then separated from it. The vibrations of the rotor, at the journal and at the weight, were measured with gap sensors and laser displacement sensors. Vibration of rotor supported by journal bearings was analyzed with FFT analyzer. Frequencies of critical speed and oil whip are shown in comparison with each other.
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Tadashi NANBA, Hiromu HASHIMOTO
Article type: Article
Session ID: S1105-1-3
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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The machine tends to low energy and high efficiency. It was mainly used for oil bearing. Then, it is important that it improve the bearing performance to raise the performance of the rotational machinery. To such a problem, it was studied optimum design to improve characteristics of bearing in recently. In general, when it performed the bearing design, it was performed as multipurpose optimum design to optimize a number of objective functions at the same time. Previously, when it solve multipurpose optimum design problem, it give weight factor to each objective function, it was boil down to single objective function for the summation. However, in fact, to select weight function, it decided for try and error or judgment of value of designer. Therefore, there are problems to need the calculation number of times and take a lot of calculation time to get the optimum weight factor. In this paper, it studies about optimum design of groove geometry for thrust bearing with weight factor consideration.
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Masaya KOBAYASHI, Masayuki OCHIAI, Hiromu HASHIMOTO
Article type: Article
Session ID: S1105-1-4
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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Journal bearings are widely used for supporting high-speed rotational machinery, such as turbines compressors and HDD spindles, because of their high load carrying capacity, stability, and durability. Recently, the engineering trend is oriented to higher speed and smaller sizes of rotational machinery, and then it is important to enhance the stability of the journal bearings. From latest work, high stability is obtained under the starved lubrication conditions. However, the temperature rise of the lubricant may occur under the starved lubricatioa Therefore, it is necessary to know the temperature characteristics of the bearings under the starved lubrication. In this paper, the temperature rise of the lubricant under the starved lubrication in the small borejournal bearing is examined. It is found that the starved lubrication allows suppressing the temperature rise by selecting an appropriate supply lubricant quantity and reducing the friction loss.
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Yu-An TSENG, Hatsuhiko USAMI
Article type: Article
Session ID: S1105-1-5
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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The present study describes effects of surface texture on reduction of friction resistance of cemented carbide in a mixed and boundary lubricated condition. A ring on disc type testing apparatus was used for the experiment at a constant sliding speed. Different texture combinations of the ring and disc, flat-flat, micro dimples-micro dimples or parallel grooves-micro dimple were evaluated. Results of the cemented carbides were compared with those of the alloy steel to evaluate the frictional properties. It was found that the friction coefficient of the cemented carbides was smaller than that of the alloy steel in the higher applied load region in each texture combination.
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Keju CHOU, Hatsuhiko USAMI
Article type: Article
Session ID: S1105-2-1
Published: September 04, 2010
Released on J-STAGE: August 01, 2017
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The present study describes crack extension of ceramics during micro shot blasting. Various sizes of green silicon carbide and white alumina abrasives were used for the impact media and were collided to the target silicon nitride surface with a direct gas injection type blasting system. The eroded surface was analyzed with a SEM and a surface profile meter. The specimen was ruptured by a flexural test to observe the crack extension below the eroded surface region. Results showed that the crack extension was different depending on the materials and sizes of the impact abrasives and that the trans granular fracture occurred below the wear scar at smaller wear loss..
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