We have already proposed the tactile sensor with multi artificial whiskers, which mimic whiskers of animals. The proposed sensor distinguishes the types of contact objects from the condition of the deflection direction of each whisker that contacts objects. However, objects which the sensor can distinguish only simple forms of comparatively small objects. Thus, the present study will propose a new method to distinguish complicated and large objects. The proposed method uses a sensor block consist of a small number of whiskers. The sensor block will distinguish a simple local form of a large contact objects which has complicated form. The new method integrates the distinguished local surface forms of a contact object, and clarifies the type of the object. This study will perform some experiments to distinguish complicated objects and confirm the availability of the proposed method.

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Linear ultrasonic motors have been formerly designed by trial and error of designers. Therefore, the geometry of the vibrator for these linear ultrasonic motors is generally limited to simple one. The output power of the linear ultrasonic motor is not maximized by optimization for designing the geometry of the vibrator. In the present study, a linear ultrasonic motor having high power is designed using optimum geometry design method. The design method is based on a contact analysis between slider and vibrator, finite element method and genetic algorithms. The designed vibrator is manufactured and the characteristics of the motor are measured. As a result, measured natural frequencies of the vibrator agree well with the calculated ones. The maximum unloaded velocity and maximum thrust are 300 mm/s and 1.96N at the driving voltage to be 30V and the pre-load to be 4.58N, which are larger than those for previously developed linear ultrasonic motors.

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This paper describes the development of novel PZT thin films for active sliders in hard disk drives. So far, it is common that single-layered thin films are used as micro-actuators for conventional PZT thin films such as sol-gel or sputtered thin films. In this study, however, the novel composite PZT thin films are developed. In other word, the feature is that sol-gel PZT thin film is deposited on sputtered PZT thin film fabricated on Pt/Ti bottom electrode. These multi-layered composite PZT thin films are found to have the higher (111) preferred orientation as well as better P-E hysteresis loop characteristics than not only sol-gel PZT thin films but also sputtered PZT thin films. Furthermore, the piezoelectric strain constant d_<31> for the novel PZT thin films is identified to be 189×(10)^<-12>m/V. This value is 2.0 times higher than that for conventional PZT thin films and it is found that the novel PZT thin films have good piezoelectric properties.

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PLZT element that is a kind of piezo element has a unique characteristic that is called photovoltaic effect. The photovoltaic effect of the PLZT element causes very high voltage when exposed to ultraviolet light. We propose an electrostatic optical motor driven by the photovoltaic effect and electrostatic force. High voltage generated by the photovoltaic effect causes electrostatic force. And the electrostatic optical motor makes rotational motion by the electrostatic force. This new type motor has some superior characteristics such as non-contact energy supply, large rotational motion and the like. A characteristic of the electrostatic optical motor depends on the characteristic of photovoltaic effect such as maximum generated voltage and the like. In this paper, therefore, effect of polarizing applied voltage on the photovoltaic effect of the PLZT element is described due to get a PLZT element that has higher maximum generated voltage.

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This paper describes an explanation based on temperature variations across oil film of the dimple mechanism in EHL conditions. Experiments were carried out with a ball-on-disk type apparatus and temperatures of both the sliding surfaces and the oil films were measured by an improved infrared technique with two kinds of the infrared transmitting disk. Measuring the temperature of the disk surface, a disk coated by Cr layer on the contact surface was used in order to radiate infrared by itself as well as cut off the radiation from the ball surface and the oil film. When the temperature of the ball surface and the oil film, a disk which was not coated was used. Film thickness was measured by the optical interferometry technique. The temperature of the dimple was sometimes above 300K. The dimple formation can be explained by the viscosity wedge action estimated by the measured temperature differences between both the sliding surfaces.

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A comparative analysis between the simulation results for the Sofl-EHL case of two parallel sliding surfaces and the experimental and simulation results obtained using a new sliding surface called Tribo-sheet is described in this paper. The value used for the lubricant viscosity and the range adopted to compare the results are the same for both cases. The analysis shows that in the case of two parallel sliding surfaces have a higher value of friction coefficient for the observed range of sliding speed and also shows that it has a small value for the minimum film thickness according to the free deformation distance Tg, therefore leading to a higher risk of wear due to seizure. On the other hand, the experimental results obtained using tribo-sheet shows a lower friction coefficient and the simulation results show a higher pressure distribution.

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The traction coefficient μ of lubricants depends on the type of oil and also the operating conditions, such as sliding/rolling velocity, pressure, and temperature. The traction coefficient μ has the maximum value at a certain temperature. It tends to be decreased at lower or higher temperature than that. In this paper, the factors associated with the μ-temperature transition and their influence are clarified by the analyzing the μ-temperature transition condition with the lubrication regime diagram.

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The traction coefficient μ of lubricants has the maximum value at a certain temperature. It tends to be decreased with decreasing temperature in the lower temperature range. An experimental equation on μ decrease was obtained by analyzing the μ-temperature transition condition and μ-temperature properties with the lubrication regime diagram. Based oin te experimental equation, the factors associated with the μ decrease and their influence was clarified. Also, μ decrease prediction map, overlapped the contour line of μ, was made on a lubrication regime diagram.

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Roller test and ring/disk test were carried out under non-lubricating condition in high vacuum to investigate the tribological performance of particle dispersed composite platings based on electroless Ni-P alloy. Three kinds of composite platings, in which PTFE particles, BN particles, and SiC particles were dispersed, were employed. The wear rate of both plated layers with BN particles and with PTFE particles increased with increasing content of dispersed particles. The wear rate of the layer with PTFE particles was greater than that with BN particles. The influence of elastic modulus of dispersed particles on stresses in the plated layer was investigated with FEM analysis. The maximum values of Mises stress in the plated layer increased with increasing particle content and with decreasing elastic modulus of particles. The wear behavior obtained in the experiment could be well explained by the calculated stress field.

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In order to know the running-in process for ultra low friction of CNx sliding against Si_3N_4 balls in N_2,the effect of surface roughness of balls on friction coefficient was investigated. As results, it was shown that friction coefficient for all of Si_3N_4 balls decreased with sliding cycles and reached to the specific minimum values less than 0.05. For friction coefficient less than 0.01,smooth surface of ball with 30nm Ry as initial surface roughness was necessary. Smooth surfaces of CNx coating and Si_3N_4 ball after running-in provide ultra low friction after the transfer of tiny amount of CNx to Si_3N_4 ball and the generating of thin and uniform transfer film on balls.

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Lubricating performance of some vegetable oil was evaluated for life of thrust ball bearings. Vegetable oils used in life test are rapeseed oil, camellia oil, olive oil and castor oil. The results were compared with a corresponding paraffinic mineral oil. Additional tests were performed to evaluate the oxidation inhibitor for vegetable oils. The results showed better fatigue life for vegetable oils as compared to mineral oil.

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To investigate the influence of lubrication on the rolling contact fatigue strength of Si_3N_4 ceramics, the fatigue life was tested under four type of oil lubricants. The thinner oil film thickness is, the weaker the rolling contact fatigue strength becomes under the hydrodynamic lubrication, but it is nearly equal under the mixed and boundary lubrication.

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Using a two-roller testing machine, the authors have examined the surface durability of thermally sprayed WC-Cr-Ni cermet coating in lubricated rolling/sliding contact conditions. In the present investigation, the coating of 60 to 210μm in thickness was formed onto the blasted, axially ground, and circumferentially ground roller specimens made of a thermally refined carbon steel or an induction hardened carbon steel by the high energy type flame spraying (Hi-HVOF). The coated roller finished to a mirror-like condition was mated with the carburized steel roller without coating, and a maximum Hertzian stress of P_H=1.0 to 1.4GPa was applied in line contact. In the thermally refined steel substrate roller, the coating on the circumferentially ground substrate generally shows a lower durability compared with that on the axially ground substrate or blasted substrate, and this difference appears more distinctly as the coating tickness decreases. On the other hand, the induction hardened steel substrate roller shows a higher durability, and the effect of substrate surface treatment was hardly recognized.

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The pull-off force and friction force were measured by using AFM with various curvature radius of a spherical probe in air under the relative humidity controlled. The curvature radii were 9 μm. The tests were performed with single-crystalline <111> silicon and two super-water-repellent coating films by the sol-gel method. Pull-off force and friction force of silicon increased with increasing relative humidity. On the contrary, those of super-water-repellent coating film with large contact angle was independent of relative humidity. From these results, it is found that the influence of the meniscus force by the adsorbed water on the pull-off force and friction force is reduced with the super-water-repellent coating film.

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To clarify the friction and wear characteristics of spheroidal graphite cast iron under the conditions of high sliding speed and high contact pressure, the friction and wear tests of sliding a cast iron pin on the mild steel disk were carried out by using the pin-ondisk type friction and wear test rig. The wear rate changed in three steps with the increment of sliding distance. On the other hand, the coefficient of friction decreased with the increment of sliding distance, and then it was settled in some constant value. These friction and wear of cast iron are strongly influenced by friction-inducced temperature rise. So, the temperature rise of the cast iron pin near the sliding surface was measured by using the fiber-type radiation thermometer.

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The current design of magnetic disk head sliders needs an extra margin of flying height for manufacturing tolerance or environmental variation. To reduce this margin, we have developed active head sliders. These sliders carry an unimorph piezoelectric micro-actuator and their flying height can be controlled. After simulating the piezoelectric deflection and flying characteristics, we designed two types of active head sliders and fabricated them by silicon micro electro-mechanical systems (MEMS) processing. The sliders flew over a glass disk and the observed stroke of the actuator was large enough (6 nm/V) to control the flying height.

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The development of high strength aluminum alloy bolt is carried out for practical application to the Aluminum Space Frames (ASF). In this report, the hardness distribution of development bolt is examined by nano-indentation. As the result, it has been confirmed that the dispersion has little uniformly been stabilized on nano-indentation hardness of the development bolt. And the development bolt evaluated the microstructure of the bolt. And it is indicated that there is the correspondence from the FEM analysis in equivalent plastic strain and hardness.

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In the design of a transmission system, there is an object to choose the optimal specifications from the design requirements which conflict each other and various conditions such as transmitted power, rotational speed, reduction ratio, etc. Conventional design usually based on the experiment of designers and round robin calculations. There was a problem of the skill of a designer, or it takes much time to complete the design. In this study, new approach for automatic transmission system design tool was proposed. The multi-objective optimizing method based on the simplex algorithm was developed to reduce design cost and to improve design quality.

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A precise analysis has been made for the design method of a face gear-set which has non-intersect and inclined axes. A face gear-set will be designed as a replacement of conventional spiral bevel gear and hypoid gear. Firstly, theoretical equations are derived to represent the profile of the face gear. Secondly, a numerical analysis method is proposed to obtain the limitation of a narrow tooth edge and an undercut interference of the face gear. Then, the theory is verified by practical cutting of the face gear with a pinion cutter using a simple attachment fitted to an ordinary gear shaper.

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A method to locate the sound source of an abnormal noise of machinery is developed experimentally. Sound source localization is realized by means of a near-field acoustic holography (NAH). A faulty journal bearing is used to generate the actual abnormal noise. A two-dimensional distribution of complex sound pressure on a dominant frequency component is required to use the NAH, so the frequency is decided from the spectrum of the abnormal sound. Furthermore, the sound pressure distribution is acquired by a real-time measurement system, which has 64 microphones. It is decided experimentally that a timing to acquire the sound pressure distribution should be at the end of the impulsive waveform, on which the output from the phase sensitive detector is stable. It is shown that the sound source localization of the abnormal noise from the faulty bearing is realized with an optimal frequency and timing.

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This paper proposes an approach to optimal design of cam curves. In the approach, a cam curve is described with a uniform B-spline curve and then the values of B-spline control points are optimized with the Complex Method according to the utilization purpose. The algorithm is simple and the programming is easy since it only needs to compute the performance value but require no the gradient of the index function in optimization calculation. Some examples, that include an optimal design to symmetrical DRD normalized cam curve and a cam curve design to control the residual vibration with indexing cam mechanism, are shown. The outcomes sufficiently illustrate the effectiveness of the approach.

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