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Makito NAKASONE
Article type: Article
Session ID: 3003
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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A web is continuous, flexible two dimensional material such as paper, plastic film, textile, thin metal etc. then it has various applications in many industries because of their advantage of compactness or anther function. In near future, the market of optical films became very large in some industries such as crystal liquid display, PC, compact IT instrument. On the other hand, it is well known that the web is damaged by wrinkling in transportation of webs. Therefore, it is important to predict and protect the wrinkles however there is no literature treated the effectiveness of anisotropic in Young's modulus of optical film in machine direction and cross machine direction on wrinkles. This paper describes the experimental study on wrinkles or transportation of optical films and the effect of anisotropic of optical films wrinkles are clarified experimentally.
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Makoto KAMIYA
Article type: Article
Session ID: 3004
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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MAGIC (MAG-netic Intelligent Compounds) is a solidified magnetic fluid (MF) and abrasive particles (AP) of micron size. The distribution of APs in MAGIC can be controlled by applying a magnetic field. In this study, we propose the distribution model of abrasives in a grindstone which can make a mating material's surface smooth with One Path sliding. We observed the surface when the following scratch scar was formed to one scratch scar formed, beforehand in parallel. As a result, it was clear that the ridge was newly formed by interfering with the scratch mark mutually between two scratch scars. Then, we proposed to arrange abrasives to scratch the top of a ridge selectively, made the model grindstone in the simulation, and did the grinding simulation on the surface. A usual grindstone, the MAGIC grindstone, and the model grindstone which had been proposed this study were compared in the simulation.
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Shinnosuke KADOWAKI
Article type: Article
Session ID: 3005
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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In general, the wear volume of material is proportional to the inverse of its hardness. However, in our previous experiment where diamond-like carbon (DLC) was slid against a cast iron in oil, the wear volume of DLC-A with an averaged hardness of 71GPa was about one-15th of that of DLC-B with an averaged hardness of 24GPa. Thus, we assumed that the wear volume of DLC depends not on averaged hardness but on the probability, P_w that the local hardness of the cast iron is larger than that of the DLC at their contact points. Then, we obtained the hardness distributions of DLC-A, DLC-B, and the cast iron. The calculations of probabilities, P_w of DLC-A and DLC-B were 0.11% and 2.5%, respectively, indicating that P_w of DLC-A was one-23rd of P_w of DLC-B.
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Hideaki YOSHIBA
Article type: Article
Session ID: 3006
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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The roller chain is widely used as power transmission element on machines such as motorcycles and transporting machines. Life of a chain is decided on Bush by abrasion of a pin except a burst accident. In this research, I developed trial manufacture of the abrasion examination machine used a chain element. In a device to bend and straighten while pulling a chain with power of 2000N, I generate the abrasion that is similar to real abrasion. It realizes shortening of examination time and simplification of a device, miniaturization by examining it only with two links of a chain.
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Ryoko NOZAWA
Article type: Article
Session ID: 3007
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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For start torque and reliability, a ball bearing is used for posture control of a space satellite not a fluid dynamic bearing. It is Retainer Instability that cause allophone with this bearing and a torque rise. It becomes clear that torque changes when Retainer Instability occurs when a lubrication condition changes. In this research, we shot a ball bearing with a high speed camera to observe retainer behaivior when a lubrication condition changed.
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Wakana SUMI
Article type: Article
Session ID: 3008
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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In this study, we determined the optimal shape of the circulation path of the end cap for minimizing the driving torque, vibration, and noise of a linear guide. We investigated how these parameters varied when the radius curvature of the circulation path was modified. The following points were found. (1) Low noise levels were achieved when a large hole diameter and a large curvature radius were used. (2) The average frictional force was low when a large hole diameter and a large radius of curvature were used. (3) However, when the hole diameter was increased, the average frictional force and the noise level became unstable. (4) Large amounts of noise are generated, as indicated by the graph of the noise, when the vibration level is also high at high frequencies. In summary, we found that to reduce noise, it is only necessary to reduce vibration.
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Kimi KODO
Article type: Article
Session ID: 3009
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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Lubricating oil is used for many machines and devices, and lubricating oil is degraded with use. Degradation of lubricating oil is roughly classified two types, one is caused by solid particle and the other is caused by oxidation. We compared with the actual machine oil and the degradation oil which it was prepared artificially, in order to concern the possibility of this diagnosis method. As a result, we found that it is possible to know the degradation degree of the oil from the color of membrane patch.
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Shunya Kikuchi
Article type: Article
Session ID: 3010
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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The technology that positively uses "Ice" attracts our attention as a technology that decreases the negative environmental impacts. It is thought to be necessary and indispensable to understand mechanical properties of ice for efficient use of "Ice". In this research, a series of friction experiments of ice rubbed against tire rubber at cryogenic temperatures was carried out. Cryogenic hardness was also examined to investigate the influence of the elastic hysteresis of the tire rubber.
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Yasushi HOSHINO
Article type: Article
Session ID: 3011
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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In order to confirm the applicability of the aluminum alloy surface with truncated grooves on the improvement of the friction property in boundary lubricated condition. The truncation of the groove was obtained by polishing and shot peening; the later treatment was resulted in the complex surface profile. The friction experiment was carried out with a ring-on-disc testing apparatus in small amount of lubrication. The experimental results showed that the frictional resistance was smaller at the grooved surface formed by tip polishing than that of flat surface. Similar behavior was confirmed at the result of the grooved surface truncated by shot peening. The lubrication mechanism of the grooved surface with truncation was discussed.
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Hiroomi KITANO
Article type: Article
Session ID: 3012
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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The present study describes hardening of aluminum alloy by fine particle ejection technique. Various fine particles, steel, zirconia, fused silica and fly-ash were accelerated with pressurized gas and were collided to the target surface with various gas pressure and treatment time. Vickers hardness was measured on the surface with indentation loads 1 and 3mN, in order to investigate the distribution of the modified layer. The modified surface was analyzed with SEM/EDX. As results, it was confirmed that the significant increase of the hardness was obtained by the penetration and transfer of impact particles.
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Takayuki MIYAJIMA
Article type: Article
Session ID: 3013
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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Mechanical properties of carbon nano-tubes (CNTs) film grown on silicon carbide substrate fabricated by surface decomposition process were measured by indentation methodology. Not only a pyramid indenter but also sphere one was used for the measurement. It was confirmed that the indent load for the evaluation within the film by sphere indenter was significantly larger than that tested with pyramid indenter. Elastic recovery and yield stress of CNTs film were evaluated from the observation of the impression and the load-displacement curve, and applicability of sphere indentation technique was discussed.
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Masahiro TANIDA, Hiroki ANDO, Naoki MURAMATSU
Article type: Article
Session ID: 3014
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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In automated manufacturing factory, grippers which pick and place workpieces are installed on robots as endeffectors. Conventionally, pneumatic cylinders are mainly used for the grippers. However, there are many problems that the grippers are inefficient in terms of energy and need incidental equipments such as compressors and pipes. For these reasons, electrically moved grippers are expected. These days, few electric grippers exist. But these grippers are larger and heavier than the pneumatic. This reason is that a mechanism of increasing force and changing rotary motion to liner motion is necessary so that an electric motor may be used as the actuator of the electric gripper. Therefore, we try to use movable pulleys to miniaturize the electric gripper. This mechanism can increase force and change rotary motion to liner motion by one mechanism. From this point, the electric gripper may be miniaturized with this mechanism. It is shown in experiments that movable pulleys can increase the force and change the motion.
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Tomomichi ONOE, Nobuyuki IWATSUKI
Article type: Article
Session ID: 3015
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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This paper describes a wire-driven flexible link mechanism which can generate two-dimensional motion keeping stiffness against load. Bending deflection and stiffness of a coil spling are analyzed in case where a point on the coil spring is pulled with two wires. The control inputs of wire to position the tip of the spring resisting load are calculated and examined with the two dimensional trajectry control experiments. A mobile robot with four flexible link mechanism as legs can change its supporting condition by controlling position and stiffness of legs.
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Noriaki TABATA
Article type: Article
Session ID: 3016
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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The purpose of this research work is to develop MAV (micro air vehicle) based on Dragonfly's flying motion. At first, the flying motions of Dragonfly not only free flight but hovering are recorded by high speed motion camera and the movements of wings are analyzed. Then, the wing mechanism combining the links and gears based on the results of the analysis are developed. We are successful in develop two types of light weight MAV of 5.9g and it is confirmed that the wing motion of both MAVs are very similar to that of Dragonfly.
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Kazuaki ANDO
Article type: Article
Session ID: 3017
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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This paper described a study on effects of the case depth and the helix angle on the bending fatigue strength and the bending fatigue crack path of case-carburized helical gears. Bending fatigue tests of case-carburized helical gear pairs of different case depths and helix angles, meshed at the worst loading position where the maximum root stress was considered to occur, were carried out, and S-N curves were obtained. Effects of the case depth and the helix angle on the bending fatigue strength and the bending fatigue crack path of case-carburized helical gears were determined.
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Shinya SASAKI, Hiroki Mano, Yanqiu Xia, AtsuShi Korenaga, Takashi Mura ...
Article type: Article
Session ID: 3018
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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As for the vegetable oil, the application to the lubricant is expected as a material with low negative environmental impacts. However, because a lubrication performance is inferior to a conventional lubricant, the surface modification of sliding surface is needed for the 100% vegetable oil. The lubricity of the vegetable oil for several hard thin films, which are used as wear resistance materials, were examined. It reports on the result of considering suitable surface modification for the vegetable oil lubricating system.
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Tomomi HONDA, Tomoyuki SATO, Yoshiro IWAI
Article type: Article
Session ID: 3019
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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Si-DLC and Cr-DLC thin film were successfully produced as a friction reduction coating on to Al_2O_3 using plasma ion immersion deposition and dual magnetron sputter deposition with different deposition parameters. Metal Cr and Si layer were applied as bonding layers prior to or during the deposition on the samples. To investigate their tribological properties, reciprocating wear tests were carried out on the DLC coated specimens. The properties of the coated DLC film were examined by AFM, SEM, EDX and nano-indenter. As a result, Cr-DLC shows the low friction coefficient, good wear resistance and high adhesive strength. Si-DLC applied non-RF plasma also has the lowest friction coefficient, good wear resistance and the highest hardness.
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Yoshinori ISHIDA, Hatsuhiko USAMI
Article type: Article
Session ID: 3020
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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In order to confirm the applicability of the surface modification by fine particle peening for reciprocal type compressor, friction experiments were carried out at a higher applied load and lower sliding speed in small amount of lubricant. The friction interface was consisted from alloy steel (SCM415) rings and the aluminum die cast (ADC14) discs modified by fine particle peening with steel, glass beads and fly ash particles. As results, the frictional resistance of modified surface with the glass beads and it was concluded that the fine particle peening treatment was available as surface modification of aluminum die cast alloy for improvement of the sliding contact in boundary lubricated condition
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Keju CHOU, Hatsuhiko USAMI
Article type: Article
Session ID: 3021
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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A purpose of this study is the investigation of the applicability of the surface modification by fine particle peening for the surface treatment of Au plating. Surface modification by the peening treatment was carried out with various particles, glass beads, fly-ash, black silicon carbide and white alumina. Friction experiment was connected to ascertain the adhesion strength in the service condition such as bearing interface. As results, specific particles were available for the impact media for the improvement the surface treatment for Au plating.
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Ryozo NEMOTO, Kenji TAKEI, Ema TAMURA, Jyo SHIMURA
Article type: Article
Session ID: 3022
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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The machine elements such as gears, traction drives, rolling bearings, wheel/rails, and other things are used for a long period under the severe conditions of rotational speed and loading. These elements play the role which is not to break down in security. In practice, phenomena called as pitting, spalling, flaking, and the other cause the serious problems. It is important to investigate a detailed contact stress state for the contacting surfaces precisely to guarantee and calculate contact stress. strength and its life cycle. Most of above-mentioned elements are used practically in the conditions of three-dimensional contact stress state. To design the life of these elements has to calculate an auxiliary equation of the Hertzian theory. Because these auxiliary equations involve the complete integrals of theist and second kinds, computing methods are required. This report shows how to calculate the contact stress using approximation equation by arithmetic geometric mean. As a result, numerical solution has simply and precisely accomplished.
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Hiroki MATSUYAMA, Hiroyuki CHIBA, Kazutoshi TODA
Article type: Article
Session ID: 3029
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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In this study, the effects of internal geometry on friction torque of tapered roller bearing have been clarified. To decrease the rolling resistance, decreasing the number of rollers, the roller effective length, and the crowning radius in the raceways should reduce the rolling area between the roller and the raceway. And, the mean roller diameter should be increased to offset the decline in dynamic capacity from decreasing the number of rollers. Based on these results, we have developed the super-low friction torque tapered roller bearing, which consists of three basic technologies, that is optimized internal geometry, lubricating oil flow control and compactness with special heat treatment for high-capacity. The torque of developed bearing is 80% lower than that of standard tapered roller bearing. This developed bearing has a lower friction torque than the ball bearing designed to have the same calculated life.
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Hiroyuki CHIBA, Hiroki MATSUYAMA, Kazutoshi TODA
Article type: Article
Session ID: 3030
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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In this study, the effect of lubricating oil flow behavior of tapered roller bearing on friction torque have been investigated to improve fuel efficiency of vehicle. As the result, the effect of oil flow route through the bearing and oil flow control on friction torque of tapered roller bearing have been cleared. It has been found that the oil flow that moves from the inside to the outside thorough the cage in the bearing effect on the friction torque of tapered roller bearing. Both of agitating resistance and rolling resistance can be reduced by restricting oil flow into the clearance between the cage and the front face rib of the cone. It has been found that it is more effective for the reduction in agitating resistance to reduce oil stagnation by rapidly discharging the oil from inside the bearing.
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Masanori MATSUO
Article type: Article
Session ID: 3031
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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The objective of this paper is to design development sliding plain bearings for hermetic screw compressors. The tests were carried out to obtain the data for bearing performance operating at an actual condition of refrigerant-blended lubricant. The thrust bearing used here is a groove type bearing with grooves on the runner and plane surface for the stationary side. The grooves are combination of spiral shape on outer side and radial shape on inner side in order to make reverse rotation possible. This configuration of the bearing is named 'The Ribbon Type Bearing' hereafter. At starting period, injection lubrication is applied to reduce friction torque. 'The Ribbon Type Bearing' is intended to achieve higher load capacity and lower bearing loss by the pumping effect and cooling effect of the both types of grooves in comparison with a conventional spiral groove bearings. The tests were carried out using pure lubricant and refrigerant blended lubricant containing refrigerant quantity of 6wt%, 10wt% and 44wt%. Bearing film thickness, bearing temperature, and friction torque were measured to evaluate bearing performance. The operating conditions were 2500rpm rotational speed and 370kgf bearing load. At that condition using 44wt% refrigerant blended lubricant, frictional torque was about 160kgf-cm. The potential of the ribbon type bearings were well demonstrated.
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Toshihiro OZASA, Yuichiro KAJIKI, Akihiro YAMADA, Noriaki ISHII, Hiros ...
Article type: Article
Session ID: 3032
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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The authors developed a friction measuring apparatus of journal bearings based on angular deceleration. A rotor, composed of a shaft, a weight, one piece of a pair of clutch and a slight disk having many slits for pulse generation, was supported by a pair of test journal bearings. The rotor was rotated by an electric motor and then separated from it. After that, time intervals between the generated pulses were measured to calculate angular deceleration of the rotor. Then friction torque was calculated with the moment of inertia of the rotor and the angular deceleration.
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Eiichiro TSUTSUMI, Tsutomu EZUMI
Article type: Article
Session ID: 3033
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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Since a polymer material has many advantages to order materials such as easy workability and light in weight, more research and development of the material is required. Polymer material shows a unique phenomenon known as a craze, which consists of fibrils and voids. A fibril is a bunch of molecular chains and a void is a molecular cavity. It is also known that environmental chemicals encourage the growth of the craze. In this study, polycarbonate was adopted as a polymer material and ethanol as an environmental chemical. A photoelastic analysis was conducted in order to observe how the environmental chemicals affect the craze and a crack development.
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Katsumi FUKUDA, Mistuo KOBAYASHI, Kenji SUZUKI, Takashi SAWADA, Hirota ...
Article type: Article
Session ID: 3034
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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Friction is a phenomenon to have between two objects which contact and sliding by all means. In studying friction, we can raise efficiency of energy and nccesary for machine movement stability. Important in the research and development of the micromachine in particular. In this study, I use a glass wafer for a sample and make an experiment to clarify a friction characteristic in micro load area.
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Kazutake UEHARA, Fumio OBATA, Kouhei MATSUO, Yutaka KAWAMURA
Article type: Article
Session ID: 3035
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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This paper is a basic study to improve the positioning accuracy of the slide guide composed of a hardened plate made of alloy tool steel and sliders made of cast iron by reducing the friction coefficient in an ultra-lower sliding velocity region. Both sliding surfaces are finished as mirrors. The effects of lubricant additives such as amine salt of acid phosphate and sulfurized fat on reducing friction coefficients of the sliding surfaces were examined by both SRV tests and surface friction tests. Two kinds of lubricating oils of VG68 were used. One was a mineral oil and the other was a slide way lubricant on market. The optimum formulation ratios of the lubricant additives existed to reduce the friction coefficients in the ultra-lower sliding velocity region of a linear slide guide model. The amine salts of acid phosphate were effective in both sliding tests with the mineral oil and the slide way lubricant.
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Takaya HIRANO, Hiromu HASHIMOTO
Article type: Article
Session ID: 3036
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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Recent information society, very thin flexible materials such as paper, thin films we call web are used as a media of information, and then they are transported mainly by using friction between web and steel rollers. Therefore, it is necessary to understand the frictional characteristics of them. In this paper, kinetic friction characteristics between paper and steel are investigated experimentally. In the experiment, the tow types of test rigs, the high speed type and low speed type friction test rig, are used for a wide range of sliding speed and humidity. As the result of measurements, it is confirmed that the friction characteristics with sliding velocity and humidity are significant.
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Yasuhisa HATTORI
Article type: Article
Session ID: 3037
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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In this report dynamic friction characteristics of paper-based friction material subjected to vibratory loading were examined experimentally. Dynamic friction characteristics were expressed in the form of complex friction coefficient which was defined as the frequency response function of friction force with respect to normal force. As a result of experiment the amplitude of complex friction coefficient decreased and its phase angle became negative with the exciting frequency increased, which indicates that under dynamic condition friction force arises behind normal force and its amplitude is reduced. This phenomenon is decided as an effect of weeping of lubricant at sliding surface, which was confirmed by measuring deformation change of the material under vibratory loading and by calculating complex friction coefficient considering poroelastic properties of the material and load sharing between solid and fluid at sliding surface.
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Yooichi MURAI, Shigeru ARAI, Haruo MIURA
Article type: Article
Session ID: 3038
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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We developed a test equipment for rod packings for investigations of low-leak rod packings to enable developing small high-pressure hydrogen compressors for hydrogen stations. These stations will supply high-pressure hydrogen gas to fuel-cell automobiles. The equipment can be used to measure the pressure in the test chamber between rod packings in a reciprocating rod and the amount of leakage during one cycle. We measured the performance of scroll-cut rod packings with this equipment. We found that oil supply is more effective in seal characteristics than in friction characteristics.
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Masaaki MIYATAKE, Shigeka YOSHIMOTO, Shinpei TANAKA
Article type: Article
Session ID: 3039
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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Recently, linear guide way systems supported by the surface-compensated aerostatic bearings are widely used for ultra-precision machines, such as semiconductor photolithography machines and ultra-precision measurement machines. In the previous paper, authors proposed the new type of surface-compensated aerostatic thrust bearings using porous material and improvement method of static stiffness of this type of bearings. It was found that proposed method is effective in increasing the static stiffness. In this paper, dynamic characteristics of surface-compensated aerostatic porous thrust bearings with 2nd restrictor inserting into an air feed port is investigated.
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Tadashi NANBA, Hiromu HASHIMOTO
Article type: Article
Session ID: 3040
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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Hydrodynamic air film thrust bearings are widely used for very high speed, lightly loaded rotating in many machinery because of their low friction, noiseless operation, simple structure etc. In the thrust air beading, grooved bearing have an advantage of high stability and load caring capacity, and then, the characteristics of the bearing is strongly influenced by bearing geometry, such as groove shape, groove depth, groove width, number of grooves, seal radius. Therefore, it is important to optimize geometry, however as for as the authors know, there is no literature treated above optimization. This paper describes the optimization of bearing geometry of thrust air bearing for improving various bearing characteristics theoretically.
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Yasumi OZAWA
Article type: Article
Session ID: 3041
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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The complicated phenomena such as pressure depressions, shock waves and the negative pressure, are detected in the air flow with a large bearing clearance or high supply pressure in an externally pressurized gas-lubricated circular thrust bearing. The pressure depression, which decreases the bearing load carrying capacity, is an undesirable phenomenon occurring in this gas bearing. The static characteristics of bearing for the non-contacting suspension support and conveyance of the object utilizing the negative pressure of this gas bearing is investigated numerically, and is also discussed in this paper.
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Fumio TAKEUCHI, Tadashi NANBA, Hiromu HASHIMOTO
Article type: Article
Session ID: 3042
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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This paper describes the experimental verifications of optimized high speed thrust air bearings according to two types of objective functions. In the experiment, various bearing characteristics such as stiffness of air film, film thickness, friction toque are measured by using specially designed test rig for a wide range of rotational speed. The experimental results of optimized bearings are compared with that of original spiral groove bearing and it is found that the effectiveness of optimizations is very significant.
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Kei SOMAYA, Shigeka YOSHIMOTO, Masaaki MIYATAKE
Article type: Article
Session ID: 3043
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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Recently, aerodynamic bump foil bearings have attracted considerable attentions in turbo machines. However, the structure of bump foils is usually very complicated and it is considered to be difficult to manufacture these foils. This paper proposes a foil thrust bearing using silicon rubber sheets as compliant foundation instead of bump foils. The structure of the proposed foil bearing is much simpler than that of foil thrust bearings with bump foils. In this paper, the theoretical static characteristics of the proposed thrust foil bearing are investigated and are compared with experimental results.
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Hirotsugu HAYASHI
Article type: Article
Session ID: 3044
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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In this paper, analysis on stability of circular journal bearings are proposed by using approximations by two straight lines for boundary profiles in starved lubrication. It is clarified that dynamic characteristics of boundary profiles of leading and trailing films affected in analysis of oil whirl.
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Hirotsugu HAYASHI, Syunji KAMO
Article type: Article
Session ID: 3045
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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In floating ring journal bearings, there are two oil films outside and inside a floating ring. Lubricant to form the inner oil film is supplied through oil holes of the floating ring, then a lubricant starvation occurs sometimes in the inner film. This paper presents the effects of lubricant starvation on stability of the two types of floating ring journal bearings. From the results, it is found that the range of stability increases as the inner oil film starves and characteristics of semi floating bearings are improved as compared with full floating bearings.
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Takashi YATAGAI, Masayuki OCHIAI, Hiromu HASHIMOTO
Article type: Article
Session ID: 3046
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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Journal bearings are widely used for supporting high speed rotating machinery such as turbine, compressor and HDD spindle etc, because of their high load carrying capacity, stability and durability. Resently, the engineering trend is oriented to higher speed and smaller sizes of rotating machinery, and then it is important to enhance stabilities for the journal bearings. Tilting pad journal bearing is generally used for high-speed rotating machineries because of their advantages of stabilization. However, there are some problems using for compact size rotating machines for their high manufacturing cost and complicated structure. Therefore, it is necessary to enhance the stability of more simple bearings compared with tilting pad bearing in order to use for small size rotating machinery. In this paper, the effects of the starvation mechanism on the stability of journal bearing are examined theoretically and experimentally. It is found that the stabilization of journal bearings is improved drastically by suitable combination of the lubrication conditions.
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Toshiharu KAZAMA, Tadamasa TSURUNO
Article type: Article
Session ID: 3047
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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Temperature of tribological parts of axial piston pumps with a mechanism of a rotating cylinder-block or a rotating swash-plate was measured. For the rotating cylinder-block type pump, five thermo-couples were embedded in the swash-plate and one thermistor was placed in the suction conduit. For the rotating swash-plate type pump, five thermo-couples were installed in the cylinder-block and one was at the casing. Hydraulic mineral oils with ISO VG68, VG46, VG32 and VG22 and a water-glycol type oil with VG32 were used as the test oil. The maximum discharge pressure was 20MPa, and the inlet oil temperature was specified at 20-40℃. At the atmospheric to maximum discharge pressures, the temperatures, flow rates and the torque were measured. In conclusion, i) The temperature of the swash-plate between the discharge and suction ports increased markedly; ii) The temperature of the cylinder-block at the bottom dead center of the pistons rose greatly; iii) The temperature rise was increased as the oil viscosity was higher, and iv) The temperature rise in the case of the water-glycol type oil was smaller than the rises of the mineral oils.
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Katsuhiro ASHIHARA, Hiromu HASHIMOTO
Article type: Article
Session ID: 3048
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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In designing of engine bearings for automobiles, it is needed to establish the mixed lubrication model considering the asperity contact between the bearing and journal surfaces. This paper describes a theoretical modeling for micro grooved bearings under the mixed lubrication conditions. In this modeling, the sectional shape of the micro grooved bearing is approximated to circular sectional shape. A contact pressure between the bearing and journal surfaces is calculated by the Hertzian contact model, and the effects of elastic deformation of bearing surface due to hydrodynamic and contact pressures are considered. A numerical calculation model is newly developed to predict bearing performance under the mixed lubrication condition in the micro grooved bearings.
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Fumihiro ITOIGAWA, Takashi NORIHISA, Hiroaki ISHIHARA, Takashi NAKAMUR ...
Article type: Article
Session ID: 3050
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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Very low boundary friction coefficient less than 0.01 appears if a lubricant containing alkyl acid phosphate is employed under low speed and low contacting pressure condition. In order to elucidate the effect of the alkyl acid phosphate on this very low friction, microscopic observations of a well-running-in surface by atomic force microscopy are conducted. From the FFM results by a cantilever of which tip is replaced by a glass sphere with 40μm of the diameter, it is found that reaction layers on well-running-in surface, which mainly consist of iron phosphate, has some effect but decisive factor on the low friction in this situation. Since, even in the case of the polished surface, alkyl acid phosphate exhibits a large effect on lower and more stable friction, the low friction may be mainly brought about by thick adsorbed layers of the alkyl acid phosphate.
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Kengo SUZUKI, Shigeo KOTAKE, Tomotsugu AOYAMA, Yasuyuki SUZUKI
Article type: Article
Session ID: 3051
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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Mieko Ishii, Seiji Heike, Takeshi Harada
Article type: Article
Session ID: 3052
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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The reliability of probes used in atomic force microscopes (AFM) must be increased. Here we report our examination of the electric reliability of two types of scanning microprobes under a small contact weight. One probe was platinum (Pt) coated and the other was made entirely from platinum. After the electric test, the current had melted the Pt-coated probes, but the prototype probe made entirely of platinum was not damaged. This study shows that a probe made of Pt is stronger than those only coated with Pt.
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Yoshimasa TAKEZAWA, Isami NITTA, Xuefeng ZHAO, Yoshitaka MAEDA
Article type: Article
Session ID: 3053
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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Hemangioma is vascular malformation and this cutaneous lesion is commonly treated with laser therapy in the dermatology field. In the past study, we examined the effect of the laser pinpoint irradiation to cutaneous melanocytic lesion with Q-switched Nd-YAG laser. But, Q-switched laser have not therapeutic effect for hemangiomas. Therefore, we newly examined to study the pinpoint laser therapy for treatment of hemangiomas with KTP continuous-wave laser. As a result of laser irradiation to blood vessel of mouse's auricle, the pinpoint laser therapy by scanning fine laser spot showed partly therapeutic effects such as narrowing without damaging the normal tissues around the lesions.
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Satoshi NOMURA, Isami NITTA, Noboru TKATSU, Xuefeng Zhao
Article type: Article
Session ID: 3054
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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A cerebral aneurysm is the dilation, bulging, or ballooning out of part of the wall of a vein or artery in the brain. If the cerebral aneurysm ruptures, it will become serious life-threatening condition. An aneurysm clip (sugita clip) is a medical instrumentation that is used in operation of the cerebral aneurysm to clip the ruptured aneurysm and to reduce the risk of rebleeding. In order to prevent the sugita clips from slipping out of the blood vessels, a number of pyramidal depressions are formed on their clamp surfaces. However, it was not verified whether the form of pyramidal depression was optimum or not. In this research, we used a THG laser process machine to produce the clamp surface with circular depressions or grooves. Frictional characteristics of each clamp surface was examined.
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Koichi OHTOMI
Article type: Article
Session ID: 3104
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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Nozomu KOGISO
Article type: Article
Session ID: 3105
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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This paper concentrates on how to get along with 3D CAD in conceptual design education. The conceptual design process is decomposed to the three steps; i) design specification determination step, ii) idea generation step, and iii) verification step. 3D CAD is considered as a verification tool and applied to the last step to evaluate the feasibility based on the design specifications. Moreover, the evaluation items are decomposed in order to perform the verifications coincided with the 3D model construction step. Efficiency of this method is investigated through the undergraduate design class.
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Ryo HORIUCHI, Shinji NISHIWAKI, Kazuhiro IZUI, Masataka YOSHIMURA, Anc ...
Article type: Article
Session ID: 3106
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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This paper proposes an integrated design method for the design of practical compliant mechanisms. This proposed method consists of two steps. First a topology optimization is performed to provide an optimal topology and rough shape outlines of the structure. In the second step, the outline of the optimal structure is extracted from the topology optimization results, and the detailed smooth outline is created based on a newly developed extraction method based on the level set theory. Finally, a simple design example and its prototype are provided in order to confirm the validity and utility of the proposed method.
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Hiroo SAKAMOTO, Kikuo FUJITA
Article type: Article
Session ID: 3107
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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This paper discusses prerequisites and effects of structural design optimization methodologies for electric appliances and verifies a practical case under such a discussion. Since real product design and development are restricted by time, methods, tools and resources, the selection of an appropriate methodology must be a key for the successful result. At least, methodologies of structural design optimization are ranged from experiment-based trial-and-error, CAE-based, and mathematical optimization-based ones. In this paper, a procedure and criteria for selecting an appropriate one based on the characteristics of a specific problem are structurized from a practical viewpoint. Then, the optimal design of a carved image device, which was newly developed toward advanced miniaturization of cellular phones, is studied for demonstrating the roles and effectiveness of such a procedure and criteria.
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Haruki KARIYA, Kazuhiro IZUI, Shinji NISHIWAKI, Masataka YOSHIMURA, Sh ...
Article type: Article
Session ID: 3108
Published: September 07, 2007
Released on J-STAGE: August 01, 2017
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This paper proposes a new integrated product design method for build-to-order production system based products, using the product family concept, which considers product performance, delivery lead-time and inventory cost. The development and discussion of this method uses a switchgear design problem as a concrete and practical design case. A build-to-order production system has been routinely applied to switchgear manufacturing, due to the requirements of small-scale production scenarios and diverse customer needs. However, if the risk of maintaining unsold inventory can be decreased, manufacturers can justify maintaining certain levels of versatile inventory on hand. In this paper, an inventory production system is applied to the switchgear production problem to shorten the delivery lead-time, and product family design is applied to reduce inventory cost. A three-objective optimization problem is formulated for this problem and a Pareto optimal solution set of the three objective functions is obtained to facilitate appropriate decision-making.
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