A laser processing is used for the micro-fabrication of the stent. Because processing heat causes recoagulation of molten material, it is necessary to remove it with another processing. Thus, it is required to improve the heat influence in the laser beam machining method In previous work, DEEL (Deep Electrochemical Etching with Laser assistance) was proposed, and demonstrated the possibility of the application. Currently, processing for φ5 mm tubes is succeeded by the DEEL. However, it was not possible to apply to capillary (less than 0.3mm).ln this research, DEEL processing for φ210μm tubes was performed. In this paper, applicability of DEEL processing for micro-tube and the effect of the processing condition on the product quality are reported.

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[in Japanese]

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This paper describes a method for evaluate of dynamic hydrophobicity of water droplets on superhydrophobic surfaces. The method is using a measurement of a shear force that pull off liquid bridge between two parallel plates. The result shows that low drag in in water on superhydrophobic is measurable by the method.

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RF-MEMS(Radio Frequency-Micro Electro Mechanical System) switches have contact electrodes with a contact area of less than 0.1mm2 and contact load of under mN. Thus, it is difficult for the contact electrodes to establish low contact resistance, adhesion forces, and high durability of contact resistance. Carbon nanotube (CNT) films have low adhesion forces under micro-newton loads, and high electric conductivity. However, CNT films have high contact resistance. In order to use CNT films as RF-MEMS switches, it is necessary to reduce the high contact resistance. In this study, CNT films on silicon substrates were electroplated(copper, silver ,gold, platinum, rhodium) after gold evaporation in order to reduce the high resistance of CNT mms・ Contact resistances of the electroplated were measured. The plating on CNT films and reducing their contact resistances were successfully achieved, and the contact resistance was more stable than that of the metal plate.

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Here we propose a device that can amplify odor intensity by concentrating odorous chemicals contained in air. The device consists of an air pump, an adsorbent, and a heater. Air samples are sucked into the device by using the pump. The gaseous chemical compounds contained in the air samples are trapped on the adsorbent. The concentrated odor vapor is generated by adding heat to the adsorbent to desorb the chemicals accumulated on its surface. The generated odor vapor is delivered to the user's nose by using the air pump, and thus, the intensified odor is presented to the user. Experimental results are presented to show the feasibility of the odor intensity amplification. The user of the device can clearly perceive an odor even if its concentration is below the human detection limit.

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The purpose of this study is to develop a device that combines exercise and entertainment Therefore, we developed an application and the driving device to visualize the energy consumption during this exercise. The first experiment set utilizes the smartphone you are familiar with every day. This device operates the driving device (furifuri-mini car) by shaking a smartphone. The acceleration sensor in the smartphone gets the information and transmits it to the driving device (furifuri-mini car). We utilized the Arduino of open source hardware were to control the driving device (furifuri-mini car). For the wireless communication between the smartphone and the driving device (furifuri-mini car) Bluetooth is utilized. The second experiment set utilizes a jump rope action. In this experiment set, jump rope action is used to operate the driving device (jumping-mini car). The wireless communication between the equipment and the driving device (jumping-mini car) is through the Zigbee wireless module. The result of the test is both of the driving devices responded correctly to the shaking of the smartphone and the jump rope action.

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Abstract: Manipulators which can be driven in high temperature environments have great possibilities of applications. Ordinary actuators are driven with functional materials, for example, electromagnet or piezo electric devices. Therefore, those actuators are difficult to be used in high temperature environments. We have proposed gas/liquid phase change actuator and tried to apply them to high temperature environments. We fabricate the prototype actuator which consists 0f Inconel alloy bellow, external spring, Tri Ethylene Glycol (TEG) as working fluid and heater. TEG has the boiling temperature under ordinary atmosphere around 287℃. Because of this high value of boiling point temperature, TEG is suitable for the actuator which will be driven in around 300℃temperature environments. In the 300℃ atmosphere, the actuator was driven by heater and it produced 2.4mm displacements. As a result of driving experiment, we confirm that our proposed actuator can be driven in 300℃ high temperature environment.

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A transducer for an ultrasonic motor for cryogenic temperature environment was fabricated. In the environment, a thermal stress is generated on the transducer. The motor is composed of a bolt-clamped Langevin-type transducer (BLT) and a rotor. To reduce the influence by thermal stress shift and to have high vibration velocity, a constituent material of the BLT is modified. The body parts of the BLT was made of SUS304 and the bolt of the BLT was made of titanium. We have evaluated the relationship between vibration velocity and the thermal stress. We have succeeded in reducing the thermal stress under the temperature condition from 4.5K to 293K.

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This paper presents a multi-DOF (degrees of freedom) microactuator system using a high frequency alternating-pressure source. The alternating flow from the pressure source is rectified by the synchronized active valves to drive plural hydraulic microactuators. To increase the position resolution and downsize the pressure source, the driving frequency was increased using high response piezoelectric elements. Thin piezoelectric valves and an alternating-pressure source were proposed and developed using piezoelectric bimorph disks. In addition, a 10 mm long bending rubber actuator with two chambers was fabricated and a system was constructed. The bending motion of the actuator was experimentally clarified.

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Micropumps are required in various applications including cooling systems for microelectronic devices, and fluid power systems for microactuators. Electro-conjugate fluid (ECF) micropumps have attracted attention due to its simple structure and high output power density. According to previous research, the ECF micropump tends to increase its power density when size of electrodes decreases. However, it is difficult to fabricate smaller electrodes whose height maintains. We developed mini-like TPSE to investigate the characteristics of ECF micropumps with smaller electrodes using the MEMS fabrication process of relatively larger electrode structures. In order to overcome larger flow resistance in mini-like TPSE, we propose triangular prism - tapered slit electrodes pairs (TPTSE). Electrode gaps of 200μm, 100μm and 50μm were been fabricated successfully using the MEMS technology. The experimental results proved that the higher flow rate could be obtained in TPTSE. It is concluded that their ECF micropump has the potential to generate the higher output power density.

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Surface acoustic wave motor has been investigated and then its superior performances such as high speed, high thrust, quick response and so on are demonstrated. However, for high performance operationg of the SAW motor, huge laboratory setup are required. From the view point of low-profile elements of the motor, namely, thin stator and thin slider, low-profile actuator system should be designed.

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A planar-type tripod parallel mechanism has a larger motion space and greater tilt angles. The tripod parallel mechanism for a motion base has three legs translating on the ground. A scale model of the tripod parallel mechanism with planar actuators is designed and fabricated. The planar actuation is performed by two-axis Sawyer-type linear motors with open loop control, free to move above the ground on aerostatic bearings. A posicast control scheme for the three planar actuators is applied to improve a step response behavior. The experimental results show that the control algorithm has good positioning performance.

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This paper reports on built-in position sensing on an electrostatic induction actuator, combined with burst signal driving. The actuator has three-phase electrodes for driving, which are segmented into two units. Position of the slider sheet is estimated by the ratio of the capacitances of the two units. Capacitance measurement is done within inactive periods of burst signal driving. During the inactive periods, the circuit for sensing is closed such that high-frequency sensing signal flows through the driving electrodes. The experimental results show that the proposed method can successfully estimate the position of the slider, regardless of sheet materials.

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A stacked piezoelectric actuator is used for precision positioning because of high resolution, large generative force and high responsiveness. It is usually used in compressive load because it is weak in tensile load. However, there are no detail reports about influence of load on characteristics such as displacement and permittivity. In the previous work, we obtained results that the behavior of displacement and relative permittivity of stacked piezoelectric actuators for the load did not match under the same measurement condition, and that these behaviors varied by the input voltage amplitude and the offset voltage. In the present paper, we measure the displacement and relative permittivity characteristics of stacked piezoelectric actuators which have different material properties. As a result, behavior of the displacement and relative permittivity for load are different for each stacked piezoelectric actuator.

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Abstract- This paper presents research on a new vibration suppression method based on micro step drive for HB stepping motors. This drive method cancels out the cogging torque without using any additional electronic devices and mechanical parts such as angler position sensors. This method is derived by considering the non-linear torque characteristics of the motor so as to maintain the vibration suppression performance at low motor current settings. Experiments for this method conducted to evaluate the rotor vibration are presented.

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Generally, a fishing reel utilizes a gear pair, and vibration caused by the gear pair engagement occurs when a handle of reel rotates. The vibration is transmitted to a tip of a finger via the handle. When this vibration is large, an angler feels uncomfortable. It is known that a rotational feeling in a fishing reel strongly depends on the amplitude of the mesh frequency of the gear pair. It has been confirmed that the rotational feeling changes when the rotational speed of a handle changes. In order to evaluate the rotational feeling, a vibration generating machine (Vibration Simulator) is developed to simulate the vibration in actual products. After verification of this simulator, the relationship between a rotational feeling in reel and transmission error is investigated with the simulator.

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In order to reduce windage loss 0f a helical gear unit under high speed condition, vacuumization by self pumping feature of the unit had been proposed. This paper introduces some experimental results concerning power losses due to implementation of the concept and its contribution. The method can vacuum the gearbox to a minimum of -0.085 MPa (Gage pressure) at 4000 r/min with the spacing of 0.2mm between the gear outline and shrouding parts. Based on experiments, loss was classified into four types, mechanical loss L_m, windage loss L_w pressure difference loss L_p, and turning flow loss If. It is induced by the reaction between atmospheric air and axial sweep of tooth movement that make circulating flow in the exhaust port, and is dependent on the configuration of exhaust port. Furthermore L_p proved to be the most prominent part in place of L_w which is due to the work done by the gears rotating against the pressure difference between the tooth surfaces 0f high pressure region and low pressure region.

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Regarding 10 Face Gear, the measuring method of the tooth thickness on a processing machine has not been established yet. As this solution, we propose the measuring method which uses a disk shape probe with edge to trace the tooth flank of Face Gear. This article shows the theoretical diameter of circle to contact with transverse theoretical tooth form of Face Gear. Then the relation with this diameter and the position of the tooth depth direction is described. And the evaluation procedure for the tooth thickness of Face Gear by using the position of measuring probe is shown. As the conclusion, the dimensional control for the tooth thickness of Face Gear on a processing machine can be possible.

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Planetary gear system has the strong point at their compact size comparing with high load capability. But it is more complicated comparing with parallel shaft gear systems. When manufactured gear machinery's vibration level is high against the estimated level at design stage, vibration diagnosis without reassembling because vibration characteristics changes easily with assembly error. In this study, we made a planetary gear apparatus that planetary pinion's vibration can be measured. Vibrational behavior of the apparatus is measured and its characteristics is discussed comparing with parallel shaft gear system's vibrational behavior.

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Aerodynamic foil bearings have attracted considerable attention for their application in achieving low power consumption in small-sized turbo machines, excellent stability at high speed and durability at high temperature. In order to ensure the safe operation of turbo machines, it is very important to assess the dynamic behavior of foil bearings with time-varying loads. However, few reports have been published on the dynamic characteristics of foil thrust bearings. In this paper, to clarify of the dynamic behavior, we manufactured small foil thrust bearing, and investigated the impulse response of a rotor supported by the foil thrust bearing experimentally. As a result, it was found that the dynamic characteristics of the treated foil thrust bearing decrease as the rotational speed increases.

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Diagnosis of rolling bearing failure is very difficult for conventional method in the case that the failure is small and that rotation speed is low. Establishment of effective diagnosis method is an important issue. The authors had proposed a new diagnostic method using piezoelectric jerk sensor, and shown that the method were available for a failure ill outer ring of rolling bearing. In this paper, the effectiveness for a case that the rolling bearing has a failure in roller element is investigated. Also real-time processing system of the diagnosis method is constructed, and effectiveness of the system is shown experimentally.

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Externally pressurized gas journal bearings with an asymmetric gas supply mechanism have a large load capacity compared with conventional symmetric gas supply bearings. We propose that the bearing is applicable for use in an X-ray CT gantry. The adaptation of this gas bearing to the device can conceivably increase the rotational speed and decrease the operating noise. This is effective for reduction of radiation exposure and stress on a patient. To verify the effectiveness of the bearing, rotational tests using a 60 mm diameter test bearing was conducted. The rotor vibration amplitude decreased under controlled supply pressure conditions compared with conventional supply pressure conditions.

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The present study presents an applicability of surface plastic flow process consisted from a shot peening and a burnishing as a surface modification for decrease and stabilize of friction resistance. Aluminum alloy (5056) disc used for the specimen was shot-peened to penetrate molybdenum disulfide (MoS_2) then was burnished with cemented carbide roller. The disc specimen fabricated micro dimples in advance to the M0S2 penetration was prepared. The tribological properties of the treated surface was evaluated with a ring on disc type testing apparatus in lubricated condition. As results, significant decrease of the friction resistance was found on the burnished surface fabricated the micro dimples in advance to the MoS_2 penetration.

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2-D Surface roughness parameters, which express Geometrical Product Specification (GPS), are defined as an industrial standard by ISO. The surface roughness parameters defined by 2-D contour curve are widely used in engineering fields. Nowadays, 3-D surface roughness parameters are required to be applied according to the improvement of measurement technologies. In tribology fields, several 3-D surface roughness parameters have been proposed. However, the surface roughness parameters which are appropriate to express tribological characteristics have not been reported yet. In this research, we proposed a novel 3-D surface roughness parameter for expressing tribological characteristics. Focusing on the periodicity of sliding surface, FFT method is applied for the analysis. In this paper, the correlation between the surface roughness parameter and the friction characteristics are discussed on the steel surface with created 3-D geometry.

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Magneto-rheological (MR) fluids are functional fluids obtained by dispersing micro-sized ferri-magnetic particles in oil. One of the features of MR fluids is that its viscosity could be controlled by magnetic field. Due to this features, the device using MR fluids as hydraulic fluid exhibit better performance in terms of shock reduction compared to a conventional fluid. For such reason, MR fluids are expected to be new hydraulic oil for applications such as dampers, actuators and brakes. However, when MR fluids used as hydraulic oil, the effects of particles is not negligible on the sliding surface. Generally, the particles dispersed in oil caused abrasive wear and oil starvation. Thus, improvement of lubricating properties for MR fluids enables expansion of its application field. In this paper, we reported the lubricating properties of MR fluids focusing on behavior of dispersed particles by sliding test and in-situ observation

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ZnDTP has two roles as antioxidants and antiwear agents. This additive forms tribo-films which improve tribological properties. For clarification of the improving mechanism, most of the investigations show analyzed results of the composition of tribo-films. However the relationship between the tribological properties and the tribo-film formation process has not been clarified. In this study, the formation process of the tribo-films was investigated with FT-IR. The sliding surfaces were analyzed in l, 5, 10, 30 minutes, and the time-dependent change of these spectra were observed. The formation process of tribo-films derived from ZnDTP was discussed from the friction behavior and the analyzed results.

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Ionic liquids are expected to be used as novel high-performance lubricants because they have attractive characteristics such as low volatility, high-thermal stability, and oxidation stability. It is known that ionic liquids exhibit excellent lubricity for metals with halogen elements in their molecular structure, but corrosive damage occurs at the same time on worn surfaces lubricated with the ionic liquids. To prevent such corrosive phenomena, it is necessary to use a halogen-free ionic liquid, which lubricity is inferior compared with halogen-containing ionic liquids. In previous study, tribological performance of various combinations between halogen-free ionic liquids and sliding materials were investigated. In the study, the difference in the tribological performance of kind of halogen-free ionic liquids was observable in the case of H-free DLC as sliding materials. Tribological mechanism of halogen-free ionic liquids against H-free DLC was investigated using AFM and TOF-SIMS.

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In recent years, oxidation degradation of the turbine basis oil becomes a serious problem in combined cycle power plant. It is important to detect a sign of oxidation degradation from early stage of degradation for degradation diagnosis method and deal to prevent this problem. In this laboratory, new deterioration diagnosis method for lubricating oils by the colorimetric analysis of membrane patches was developed. In the previous study, the oxidized turbine oils were investigated to clarify the relationship between oxidation process of the turbine oil with additives and change of color of membrane patches. In this study, we investigated the relationship between the oxidation process of the turbine oil without additives and the membrane patch color, and we discussed the influence of oxidation process of hydrocarbon on color of membrane patches.

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An observation of sliding surfaces and a measurement of the amount of wear are generally performed in order to evaluate tribological characteristics. However, we don't know how friction and wear phenomena change between sliding surfaces during experiments. In this study, the visualization and evaluation of tribological phenomena of cast iron was attempted by using the in-situ observation and AE measurement method. Tribological phenomena of two kinds of cast irons, a flake graphite cast iron (FC) and a spheroidal graphite cast iron (FCD), were examined. It was found from the in-situ observations that the graphite inside the cast iron is extruded to the sliding surface by frictional stress. Also, the friction force and the AE signal level decreased by the effect of the extruded graphite because the graphite on the sliding surface acts as a lubricant. Since the difference in materials can be evaluated from the in-situ observation and the AE signal, this method would become a powerful tool to find out the most suitable tribo-material.

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Diamond-like carbon (DLC) coatings have begun to appear attractive for automotive parts due to their excellent friction and wear resistance properties. In recent years, many researchers focus on their tribological properties under boundary lubricated contacts. Especially, it is well known that hydrogen free ta-C DLC coating lubricated with base oil containing ashless friction modifier glycerol mono-oleate (GMO) give ultra-low friction. On the other hands, ZnDTP is widely used as the antiwear additives in engine oil, and many researchers have evaluated the tribological performance of DLC coatings lubricated with base oil containing ZnDTP. In this study, we investigated the tribological properties of ta-C coating lubricated with PAO containing ashless friction modifiers, anti-wear additives ZnDTP and mixture of ashless friction modifiers +ZnDTP. ta-C coating with PAO containing ashless friction modifiers showed ultra-low friction. However, it is not possible to confirm ultra- low friction lubricated with ashless friction modifiers +ZnDTP additional oils.

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Components of a lubricant are divided into base oils and additives. Base oils dominates basic fluid properties of the lubricant. Additives support to improve the lubrication performance of oils. Oiliness additives have the friction decreasing effect due to the character that the adsorption layer prevent contact of the sliding surfaces. The most of studies for oiliness additives are performed with the single additive to a base oil. However, several additives are formulated in the commercial lubricants and the additives have the interaction each other. The interaction between the additives is not identified. In this research, tribological characteristics of adsorption layers of stearic acid, oleic acid and the mixture of both of them were studied for identifying the interaction of the additives. Mechanism of interaction between the additives is discussed by pendulum style friction tester, AFM and QCM.

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