Reciprocating motion/rotating motion converter which can easily operate a rotary electric generator has been developed for the purpose of utilizing vibratory energy efficiently. The converter has two pendulum type rotors which are connected each other with a spring and can rotate in a horizontal plane. The equations of motion are solved numerically to obtain parameters area of synchronous rotation to the reciprocating motion and the validity of the area is confirmed by the experiment. The proposed converter can convert the reciprocating motion to the rotating motion without making a stop due to a friction.

抄録全体を表示

The Transfer Influence Coefficient Method (TICM), which was developed by the authors, is an effective method to analyze dynamic responses of structures. The TICM has an advantage of computational speed and accuracy compared with conventional methods. However, the TICM was not available for the structures with closed loops such as truss or rahmen structures. In this paper, a new algorithm of the TICM applicable to such truss or racmen structures is presented. The algorithm presented here is shown for the in-plane free vibration analysis of two-dimensional stuctures to make the fundamental procedure clear. The validity of the newly presented algorithm is demonstrated through a numerical computation. The present algorithm remarkably has an advantage in computationl speed compared with a conventional routine.

抄録全体を表示

We developed two methods for accurate estimation of the excitation force of a motor. One is a hybrid method combining an experiment and a finite-element analysis. In the experiment, the circumferential acceleration of a motor housing was measured when the motor was in operation. Additionally, a finite-element model was created for the motor, and the circumferential acceleration response of this model was calculated. The measured and calculated accelerations were then used to estimate the motor excitation force. The other method is an elastic support method using the measured acceleration response. The amplitude and phase of excitation forces were estimated by solving an inverse dynamical problem that used as input the acceleration measured by accelerometers placed on the supporting beams of the motor. The results obtained by these methods agreed well with the excitation force measured by using load cell.

抄録全体を表示

This paper deals with active boundary control termed ABC of a thin plate for the purpose of creating a completely vibration-free state; a quiet zone, on the designated area of a target structure. First, the principle of ABC once developed for a one-dimensional structure is expanded to a two-dimensional structure, thereby enabling the generation of a quiet zone on the desired location of a structure. Then, using a transfer matrix method, an ABC system is described, fundamental properties of the system being investigated. Furthermore, in addition to conventional boundary conditions, two more boundary conditions are found to be created using ABC. Moreover, it is found that ABC has the capability of producing a completely vibration-free state on the designated area. Finally, in an effort to verify the validity of ABC presented in the work, a numerical analysis is conducted, demonstrating the capability of ABC using a simply supported panel.

抄録全体を表示

This paper deals with active wave control of a flexible beam using a wave filter constructed with smart sensors. It is the purpose of this paper to present a novel wave filtering method using PVDF film sensor and its application for adaptive feedforward control system. Firstly, the design procedure of the wave filter using shaped PVDF sensors is presented. When introducing PVDF sensor, shaping function is defined as a complex function. In this case, multiplying an imaginary unit is equivalent to making the phase difference of 90 degree. Next, from a viewpoint of numerical analysis, the accuracy of the wave filter and the performance of the control system is clarified. Finally, an experiment of the active wave feedforward control system is carried out, demonstrating the validity of the proposed method.

抄録全体を表示

This paper addresses the active power flow control of a vibrating plate. Unlike conventional modal-based vibration control, power flow control falling into a category of active wave control has the potential for suppressing all the vibration modes of a target structure. From a viewpoint of wave propagation, this paper pressents a novel power flow control using vibration intensity as a criterion of vibration energy flow. By expanding the conception of the approach presented in the work, a control method to generate a quiet zone on a designated area of the target plate is then proposed. Finally, a numerical simulation as well as an experiment using adaptive feedforward control was conducted, demonstrating the validity of the proposed active power flow control.

抄録全体を表示

The nonlinear characteristics of multi-surface liquid motion in a rectangular tank are investigated. The rectangular tank is divided into two parts by the partition, which is perpendicular to the bottom of the tank and does not reach the bottom. The nonlinearity of the liquid surface oscillation is considered in the response analysis of the sloshing motion. The nonlinear ordinary differential equations governing the liquid surface oscillation are derived. The time histories of the liquid surface displacement are calculated to the harmonic pitching excitations. An experiment was conducted using a model tank. A fairly good agreement was found between the theoretical and experimental results. It is shown that the nonlinear analysis is important for estimating the sloshing phenomena.

抄録全体を表示

We have been conducting research on the derailment and overturning of railway vehicles caused by earthquakes. Until now, numerical simulation has been shedding light on the dynamic behavior and running safety limits of vehicles on a vibrating track, and the results of the simulation now being effectively used in the design of railway structures. To confirm the validity of the simulation analysis, we carried out an experiment using a full-scale half-carbody mounted on a Shinkansen bogie, which was placed on a tri-axial structural vibration test rig. During the test, we could observe the carbody, bogie and wheels jumping from the rails, demonstrating behavior against the vibration. The simulation analyzed the experiment condition. The results of the simulation agreed with those obtained the experiment.

抄録全体を表示

This paper deals with a calculation method of free vibration of the moving belt of which axial tension, bending rigidity and rotary inertia are taken into consideration. By considering the moving belt the enough long simply supported beam with two pairs of moving rollers, the vibration of the moving belt is considered forced vibration by unknown forces and bending moments at positions of rollers. Using conditions of constraint that both displacements and slopes at the positions of rollers should be zero, simultaneous integral equations of Volterra type are obtained. The solution of the free vibration of the moving belt is obtained by solving these simultaneous equations numerically. Static displacement, divergent solution or vibrating solution is obtained in accordance with axial tension and moving speed of the belt.

抄録全体を表示

The mid-story seismic isolated building has isolators at the mid-story and it is expected to apply for seismic retrofit. The elevator for mid-story seismic isolated buildings receives strong rail bending stress by large deformation at the isolated floor. A new elevator system has been established to reduce the rail stress. The system has a long rail fixing span at the isolated floor. But it has complicated dynamic behavior such as large rail deformation and guide contact with the rail. To evaluate those dynamic responses, we developed a nonlinear finite element model. By the model, we can evaluate the earthquake transient behavior and check the rail bending stress. The simulation result was validated by the experiment.

抄録全体を表示

Elevator rope for high-rise building is excited forcibly by the displacements of the building induced by wind forces. The exact solution of forced vibration of a rope with time-varying length is presented, on the assumption that the rope tension and the moving velocity is constant, and damping coefficient of the rope is zero. Virtual sources of waves which can be assigned to reflecting waves are used for obtaining the exact solution. Finite difference analyses of the rope vibration are also performed to verify the validity of this exact solution. The calculated results of finite difference analyses are in fairly good agreement with the calculated results of the exact solution.

抄録全体を表示

In the automobile frontal collision, the maximum value of the chest deceleration is one of the most important performance indexes for the occupant protection, and depends on the time history of the car deceleration. Therefore, it is important to analyze the relationship between the chest and car deceleration, and find the car crash characteristic which causes the minimum chest deceleration. In the most research, 2 DOF model (car and occupant) at translation motion was generally used. However, it is difficult to understand an occupant impact because a real occupant is restrained by the shoulder and lap seatbelt and the upper body has rotational motion during a collision. In this paper, the relationship between the chest and car deceleration were analyzed by 4 DOF model taking into consideration its rotation. Moreover the effect of a force limiter of a seatbelt was also examined. Based on the theoretical and experimental results, we derived the knowledge for an optimum automotive crash design.

抄録全体を表示

This paper proposed new micro electrostatic driving mechanisms utilizing anisotropic feature of friction. One of the driving mechanisms consisted of parallel plate electrodes and a slanted-fiber sheet between the electrodes. When AC voltage was applied between the electrodes, alternative electrostatic force caused linear motion of the mechanism due to anisotropic feature of the friction between fibers and the lower electrode. The achieved velocity was about 10 mm/s in reverse of the fiber-slanted direction, and it roughly agreed with the numerical calculation based on a lamped dynamic model. Another mechanism was proposed because it was difficult to control friction coefficient and critical frequency of driving mechanism by the slanted-fiber sheet. It consisted of parallel plate electrodes and two slanted-plates made of polyester between the electrodes. The achieved velocity was about 5 mm/s. However, the driving direction of slanted-plate mover was opposite of the direction of slanted-fiber mover. Based on this experimental fact, relationship between the driving direction and the friction coefficient was investigated. We also proposed a rotational driving mechanism and a linear driving mover without a lead to provide voltage to the mover.

抄録全体を表示

This paper describes the modeling and analysis of an elastic tongue mechanism of a talking robot WT-3 (Waseda Talker-No.3) and the development of an acoustic simulator for the construction of the computational model of human speech production. WT-3 consists of lungs, vocal cords and articulators. Because they were composed of an elastic rubber to make various shapes and to seal the air and sound, it was difficult to estimate and analyze the mechanisms. Therefore, we constructed a modeling method to simulate the shape of the elastic mechanisms using rigid links. This method is applicable to all the elastic body. We developed an acoustic simulator for WT-3 based on this method.

抄録全体を表示

This paper introduces and describes a new type of snake-like robot, a two-joint, two-steering snake-like robot, and its control method. We first present the mechanical design of this snake-like robot that is inspired by a mathematical perspective on transforming its kinematical equation into three-chain, single-generator chained form, in a mathematical framework, differential geometry. Especially, we assume a virtual steering at the head of the first link of the snake-like robot, which makes the transformation possible. We secondly present a path following feedback control method based on such chained form that enables the first link to follow a straight line at a constant velocity. Of course, it is also possible for the first link to take any desired position and orientation by following a couple of paths under this feedback control method. The validity of the mechanical design of the snake-like robot, the transformation of its kinematical equation, and its control method is verified by computer simulations.

抄録全体を表示

In the industrial world, not only autonomous machinery as industrial robots but also man-machine cooperative systems as power-assist systems have attracted special interest recently. Kondo, et al. proposed the scheme of Man-Machine Collaborated Robotic Systems (MMCRSs) and its application to some assembling work. In MMCRSs, efficient mode switching from human-oriented operation to machine-oriented operation is important. However, its issue has not been fully addressed yet. This study discusses a mode switching control method for MMCRSs. Especially, we treat the switching from a power-assist mode (PAM) to an automatic positioning mode (APM) for a simple robotic system. To obtain a smooth switching, this study utilizes a two-degree-of-freedom control system structure which consists of an on-line impedance control simulator and an LQI servo controller. Some smooth reference generation for APM is also introduced. No input saturation and/or stopping appear at the switching in this method. The effectiveness of the method is verified experimentally.

抄録全体を表示

A design method using a virtual resounant mode in the head-positioning systems of hard disk drives was developed. The virtual resonant mode is a digital filter that works like a mechanical resonant mode. In conventional control systems, it is difficult to compensate for the disturbance over the first-order mechanical resonant frequency. By using the proposed method, stable resonant modes in the control system can be designed with accuracy and it can decrease the disturbances above the first-order mechanical resonance. Application of this method to an actual hard disk drive showed that it can greatly decrease the disturbance in which the frequency is higher than first-order mechanical resonance.

抄録全体を表示

Because a magnetic levitation technique has many advantages, it is expected to be applied for some industrial works. So, the magnetic levitation system, in which a magnetically levitated hand can manipulate a small object with non-contact, was developed by the authors. In this system, 4 electromagnets are assigned on a horizontal plane for 3 dimensional positioning of the hand. However, a precise positioning is difficult because of the characteristic differences between electromagnets. In this report, magnetic flux density sensors are introduced to overcome this problem in addition to position sensors, and the adaptive control is applied. The effectiveness is confirmed through experiment.

抄録全体を表示

This paper proposes an artificial mark attached to objects for measuring 3D pose of the objects. We first proposes three marks with four point features. These differences are image processing method to extract the features : using edge extraction, using erosion, using color extraction. We compare error characteristic of these marks through measurement experiments. As results of the experiment, the method with color extraction, which has most simple image processing method, is most robust one in cases that a mark is measured from various pose (mean of error : 10.4 deg, mean of std. dev. : 7.06 deg, worst std. dev. : 24.7 deg) or is attached on surface. Moreover, the mark enables the shortest measurement time (0.478 s/6 marks). The usefulness of the mark with color extraction was verified through the success of the experiment that a manipulator handles three objects with the marks.

抄録全体を表示

The 3-D information obtained from cameras' 2D images is given as a visual line by using calibrated parameter values, and we should evaluate the calibration accouracy with respect to the visual line direction error. In this paper, the visual line direction error was examined, based on an evaluation criterion where the calibrated principal point coordinates are taken as the references of the visual line. Many important caracteristics with the calibrated parameter value errors and their resulting visual line direction errors were found out by conducting a large amount of simulations under various conditions such as the depth ratios of calibration chart, and the principal distances of cameras. Fnally, the error characteristics were analytically proved, and some formulae were derived. The formulae enable us to estimate calibration errors for any calibration conditions in advance.

抄録全体を表示

Owing to progress of the medical technology in recenty years, the basic survival of many people is being realized. However, that causes advent of the aging society, and a new issue is raised that how advance the quality of life of an elderly or a handicapped person. As one approach of the issue, it is considered to introduce the autonomous medical and health care devices that can assist the user according to the user motivation. In this paper, a movable neck supporter (MNS) is proposed for the handicapped unable to move his neck form his own motive with a high degree of disability. The proposed system has the parallel link mechanism using several pneumatic actuators. It assists the twisting and nodding motion of the user's head. By the way, the head motion is different individually, and it is all the time changing by his condition in each individual. Therefore, some adaptive control schemes are needed for the MNS. Furthermore, the pneumatic actuator has excellent compliance and flexibility, therefore that is good for the human-mechanical system. However, it also has nonlinearity, hence high precision control is difficult. Therefore, in this paper, the CMAC-PID control scheme is installed on the H 8 microcomputer, and evaluated adaptability by some control experiments.

抄録全体を表示

One of the important aspects in preliminary design is to make their products perform well without any imperfections when it spread out in the market. Therefore, we need to evaluate the products with the same kinds of products from many aspects. These evaluations can regard as multi-objective design optimization, and most likely scalar methods are used, such as the weighted sum method. In these methods, it is quite important to give optimal weight for each objective function, so that it fits with preference of the designers. Moreover, these optimal weights give us an important information of the improvements of design quantitatively. In this paper, we use data envelopment analysis (DEA), which can derive total evaluation and optimal weights from given datum from the products in the same kinds. Hence, we can derive the amount of improvement needed compared with the other products. To examine the effectiveness of the proposed method, we collect data of Ministry of Land, Infrastructure and Transport Government of Japan in 2002 and evaluate many child-seats. From the results, we could clarify a part of child seat, which should be improved, and showed its effectiveness through its considerations.

抄録全体を表示

This paper presents a new topology optimization method that supports decision-making to obtain innovative designs at the conceptual design phase for mechanical structures. This method is developed based on structural and function-oriented elements such as frame and panel elements. For each of the frame elements, the rotational angle denoting the principal direction of the second moment of inertia is included as a design variable, and a way to obtain the optimal angle is derived from Karush-Kuhn-Tucker (KKT) conditions. For the panel elements, two types of panel element are introduced based the assumed stress method. Several numerical examples confirm the validity and utility of the proposed method, which should be useful for mechanical design engineers at the conceptual design phase.

抄録全体を表示

The purpose of this paper is to predict accurate frequencies of large space structures from the results of component modal tests. We deal with structures such as large satellite antennas, which are difficult to perform modal tests on whole structure. A method, considering the effect of untested components as boundary mass and stiffness, is proposed for obtaining accurate frequencies of a structure. Boundary mass and stiffness are found by reducing mass and stiffness matrices to boundary degrees of freedom. A tested component with these reduced matrices at the boundary gives accurate frequencies of whole structures. In performing modal tests, it is important how to simulate these matrices as boundary mass and stiffness. A procedure to find boundary mass and stiffness is shown and a numerical example is given to show that the proposed method is effective for predicting accurate frequencies of whole structures.

抄録全体を表示

This paper addresses the design method of spatial filter for suppressing modal observation spillover. To eliminate the several selected modal amplitudes from structural vibration responses, a kind of modal filter is introduced. This filtering methodology can be realized by a small number of sensors, relative to the number of dominant modes in target frequency range. Proposed filter may be designed by using sensor placement to realize that the two subspaces, which are respectively spanned by a spatial filter vector and the selected target modal vectors, are orthocomplementary. Then observation spillover associated with these selected modes is suppressed. Effectiveness of proposed filter is verified numerically for a cantilever beam. Simulation results have shown its robustness for measurement error and estimation error in modal vectors, and its potential in suppressing the spillover in vibration control and health monitoring.

抄録全体を表示

We developed a transparent tactile device on touch screen interface, which provides actual keystroke and feeling of click without preventing the functions of the interface. We designed and fabricated transparent switch structure using silicone elastomer with transparency of over 88%. In this case, high visibility was realized by filling the interspaces with the sealing liquid that has near reflective index as silicone. A feeling of click is yielded by buckling phenomenon of the structure and mechanical property is measured quantitatively by comparing its keystroke and reaction force on the key top. Our device structure is flat and thin, so that it can fit on the ordinal touch screen interface easily as one of the human machine interface functions.

抄録全体を表示

We developed a roller-type sideslip tester. The developed tester was examined under the conditions that were considered in an industrial application. This paper presents confimation of practical use by verification test. We have investigated the difference between flat-type and roller-type sideslip tester. It is confimed by three types of tires. They are a low flat tire for passenger car 195/70 R-14, a high flat tire for passenger car 205/55 R-16 and a small diameter tire for minicab 5.00-10 ULT. The amount of sideslip is measured ten times by using both flat-type and roller-type sideslip tester for each tire. The feature of the flat-type and the roller-type is shown. The validity of the developed tester is confimed under the conditions that ten measurement values which are continuously measured must be located between lower and upper standard. It was found that it could be used in practical use. Some measurement results are presented in the form of parametric plots and tables.

抄録全体を表示

A method to detect production faults in flexible plastic packages using terahertz (THz) radiation is presented. Relying on the large difference between the absorption coefficients of plastic and water (for water-filled channel defects), and on the refraction index difference between plastic and air (for air-filled channel defects) our technique consists of focusing and scanning a THz beam on the sealed area of the package, followed by the detection of the transmitted signal. We tested our THz system on defects simulated by water-filled and air-filled round channels imbedded in polyethylene films, with diameters ranging 10 to 100μm. The detection limit (the minimum size of a detectable defect) depends on the conveying speed; this relationship is determined and analyzed. The results show that our THz system has the potential of being applied in an actual production line for real-time inspection.

抄録全体を表示

In order to clarify the reason why the NO_x emissions factor is higher at vehicle acceleration at intersections etc, two freight vehicles with EGR system for the reduction of NO_x were tested by on-board NO_x measurement system. Higher NO_x emissions factor was observed at lower gear operations in each vehicle. The NO_x emissions characteristics were analyzed in the view of engine torque, NO_x mass emissions and EGR ratio, considering the rate of engine speed change. As the results, it was found that lower gear operations made the rate of engine speed change higher and also made EGR ratio lower, resulting in higher NO_x emissions. This seems to be one of the factors to engender the intensive NO_x pollution at roadside.

抄録全体を表示

An Electro-Conjugate Fluid (ECF) is considered as a functional fluid like electro-hydro dynamics fluid, and it has a remarkable property that a jet flow is generated between two electrodes when a high voltage is applied to the electrodes. In this study two types of linear actuators consisting of the pistons and cylinders using an ECF are proposed. The one has a structure of a coil type electrodes, and the other has a structure of mesh type electrodes. The proposed actuators are fabricated, and their basic characteristics-such as piston velocities vs. applied voltages to electrodes and the load caracteristics are examined in the experiment. The experimental results show that the proposed linear actuators have the possibilities to be used as the functional linear actuators.

抄録全体を表示

The concept of Mizen Boushi (reliability problem prevention) has been applied in automotive development. Recently, we are promoting a quality innovation process, “GD³” that means “Good Design”, “Good Discussion” and “Good Design Review”. In the first paper, it was presented to utilize a System Design Review during development, in which we discuss potential failure modes, root causes and examine parts drawing and prototype parts design with the DRBFM (Design Review Based on Failure Mode) method. This paper will introduce that we completed the System DRBFM as a universal Mizen Boushi method, which can be utilized for discussions from a complex/complicated system to elements with hierarchy block diagrams of product and management.

抄録全体を表示

Dispatching rules for on-line production control consist of the machine selection rule for job and the operation sequence rule for each machine. In this paper, the machine selection rule is focused on. It is reported in previous researches that 2 machine selection rules ; the ECT (Earliest Completion Time) rule and the BWL (Balanced Work Load) rule perform well for high production efficiency. ECT is a rule to assign jobs to the machines which can complete their operations in the earliest time. BWL is a rule to assign jobs to machines with the aim of balancing machines' workloads. We analyze the difference between ECT and BWL in production efficiency by using the queuing theory. As a result, BWL is proved to be more efficient than ECT when the production workload is high and the difference of processing speeds among machines is large. Moreover, we propose a function to switch the machine selection rules by considering the machine workload and the processing speed difference among machines. It is confirmed that the function is effective on shortening jebs' lead-lime (LT).

抄録全体を表示

This study is intended to fabricate 3D microstructures on single crystal silicon by tribo-nano-lithography (TNL) and wet chemical etching. The processed area of single crystal silicon by diamond tip withstands etching in KOH solution, and consequently protruding microstructure can be fabricated. Transmission electron microscope (TEM), Auger electron spectroscopy (AES) and secondary ion mass spectrometry (SIMS) analyses are utilized to study the mechanism of masking effect. As a result, it can be known that crystal silicon structures are converted to amorphous silicon by TNL process, resulting in acting to the etch mask against KOH solution. Comparison of etch rate between amorphous and single crystal silicon is conducted. In addition, mechanism of protuberance, which is generated in processing under lower normal load, is studied with minute observation of processed area.

抄録全体を表示

This study is intended to fabricate 3D microstructures on single crystal silicon by tribo-nanolithography (TNL) and wet chemical etching. In previous report, it could be known that height of microstructure fabricated by the TNL and subsequent wet chemical etching can be controlled by adjusting the TNL conditions such as normal load, pitch of processing line and number of processing. This paper reports an etch result by HF solution in order to evaluate the mechanism of height change with the TNL conditions. As a result, it is found that amorphous layer formed by the TNL can be selectively etched in HF solution though non-processed area withstands etching. The mechanism of change of masking effect is evaluated by utilizing this phenomenon. As a result, it can be known that change of masking effect by normal load is resulted from change of thickness of the amorphous layer. On the other hand, those by pitch of processing line and number of processing are resulted from conversion ratio of single crystal to amorphous structure.

抄録全体を表示

This paper deals with the influence of quantity of oil supply in hobbing with minimal quantity lubrication (MQL) of cutting oil, compared with dry cutting and flooded oil, in terms of flank wear, crater wear and finished surface roughness, with changing the kinds of coating films of the hob. Experiments were carried out using a fly tool. The results obtained are summarized as follows. (1) The flank wear obtained with the quantity of oil supply of only 1 ml/h showed almost the same value as that obtained with the dry cutting, when using the TiN and (Al, Ti) N coated tools. However, it is a result of great interest that the flank wear increases with increasing in the quantity of oil supply, and the largest one was obtained when the oil was flooded. (2) The crater wear and the finished surface with the MQL system are smaller than those with the dry cutting and the flooded oil. (3) The quantities of oil supply of 1 ml/h to 15 ml/h in the MQL system are suitable for the hobbing with regards to decreasing the flank wear, the crater wear and the finished surface.

抄録全体を表示

Lapping experiment for finishing inside surface of a through hole opened in a metal-mold material by WEDM was carried out. Ultrasonic vibration was given to a resin lapping tool which was formed around the middle part of a vibration rod. To expand the lapping area, a relative spiral motion was newly applied in this experiment between the resin tool and the metal mold. The effects of the mesh number (# 1500, # 3000, # 8000) of WA abrasive in slurry and the normal lapping force (1 N, 2N, 3N, 4N, 5N) onto the characteristics of surface roughness and lapping uniformity were elucidated. The obtained results are summarised as follows. (1) The relationship between the lapping process time and the surface roughness was almost linear on the log-log graph. (2) The highest improvement rate of surface roughness in this experiment was obtained under the condition of mesh number # 1500 and lapping force 5N, and then the surface roughness of Ra 0.08 μm was obtained after the lapping process time of 120 min. (3) It is expected that much smaller surface roughness can be obtained if much greater lapping force was applied. (4) Relatively high lapping uniformity was obtained under the condition of mesh number # 1500 and lapping force 5 N though the uniformity was lower under the condition of the larger mesh number and the smaller lapping force.

抄録全体を表示

In order to investigate the influence of shot peening on the surface durability of case-hardened steel gears, the case-hardened steel gears shot-peened with different shot velocity and shot diameter were fatigue tested using a power circulating type gear testing machine. The hardness, the compres sive residual stress and the surface roughness of the gears increased by the shot peening. The failure mode of all the test gears was pitting. The surface durability of the gear shot-peened under medium condition in this experimental range was higher than that of the non-peened gear, on the other hand those of lightly or strongly shot-peened gears were as much as that. Judging from the p_max-N curves and also the [A (σ_y/√3 HV)] _max-N curves, it is denoted in this experimental range that the surface durability of case-hardened steel gears was influenced by the hardness and the surface roughness of the gears. Therefore, it is proposed in this experimental range that the medium shot peening condition, that is, 60 m/s shot velocity and 0.6 mm shot diameter, should be selected in order to improve the surface durability of case-hardened steel gears.

抄録全体を表示

The experiments for cold rolling of stainless steel sheets were made in order to clarify the effect of methods of roll polishing and surface roughness of rolls on the surface characteristics of rolled sheets such as surface gloss, surface roughness, ratio of flat area and so on. As a result, it has been shown that the surface gloss of a rolled sheet is the largest in the case of the roll polished in the axial direction with the roll roughness of 0.08 μm, and that the surface gloss is not directly affected by methods of roll polishing, roll roughness and surface roughness of rolling material but directly affected by ratio of flat area.

抄録全体を表示

The purpose of this study is to clarify the influence of lubricating conditions, such as temperature and amount of oil supplied, viscosity grade, and chemical composition of base stock, on the tooth surface strength of carburized gears. Experiments were carried out to measure the tooth surface strength and the tooth surface temperature during operation by changing the lubricating conditions. The results obtained were discussed on the basis of EHL film thickness calculated with consideration for measured tooth surface temperature. It was found that tooth surface strength under various lubricating conditions was describable using a new parameter P_Hmean λ^-0.3 which is composed of the Hertzian pressure P_Hmean and the specific film thickness λ. An empirical formula that quantitatively expressed changes in the tooth surface strength under the various conditions was obtained.

抄録全体を表示

The wear phenomenon of ultra-high molecular weight polyethylene (UHMWPE) in knee and hip prostheses is one of the major restriction factors on the longevity of these implants. In retrieved knee prostheses with screw holes in the tibial tray, cold flow into the screw holes is frequently observed on the undersurface of the UHMWPE tibial inserts. In most retrieved cases, the protruded areas of cold flow on the undersurface were located on the reverse side of the severely worn and deformed surface of the UHMWPE tibial insert. It appears that the cold flow into screw holes contributes to the increase of wear of the UHMWPE tibial insert. In this study, knee joint simulator tests and finite element analyses of the simplified knee prostheses were performed, in order to investigate the influence of the cold flow into screw holes on the wear of the UHMWPE tibial insert. The results of this study suggest that the cold flow into screw holes is associated with delamination and increase of wear in the contact area on the articulating UHMWPE surface.

抄録全体を表示

Adhesion of a spider mite to a surface of a flat smooth plate is investigated as a model for micromachine parts to adhere to and move on such surfaces. Adhesive force is measured using a setup with a cantilever at the end of which the plate is mounted. The measurement is carried out under various conditions in which plate material, surface roughness of a plate and environmental humidity are varied. The mechanism of adhesion of leg tips of a spider mite to a plate surface is also discussed. Of the forces acting between them, force from dispersion interactions is the most dominant because (1) there is high correlation between adhesive force and the component of dispersion force of surface energy in the surfaces tested : adhesive force of 8.7 μN for glass, 9.7μN for mica, 9.9μN for silicon and 12.1μN for gold ; and (2) high humidity and high surface roughness decrease adhesive force. For strong adhesion based on work of adhesion, spider mites have tenent hairs with a bell-shaped tip.

抄録全体を表示