Vibration intensity (VI) is defined as vibrating energy flow, and it is expected to be useful in the exploration of a vibrating source, and measurements of dissipated energy. There have been many studies on VI, but those which perform a quantitative analysis of VI is scarce. It remains to be clarified whether the cause of VI error is the measurement method or the basic theory of VI. In this paper, VI of a lumped mass system is defined and VI for four lumped mass systems (two proportional and two non proportional damping systems) is calculated. From calculation results of instantaneous VI, active VI, and dissipated energy, it is shown that the definition has provided the characterirtics of VI suiffciently. Next, VI in the case of damping force is not treated as internal force is calculated for each of the vibration systems. As a result, when damping force is not considered, calculation results of VI are erroneous. In particular, in the case of a non proportional damping system, an error is found not only in the quantity of energy flow but also in the direction of VI. Therefore, it is difficult to estimate dissipated energy by VI.

抄録全体を表示

In this work the vibration and stress of copper tubes caused by operation of compressors in refrigerators and air conditioners are considered. Natural frequencies and stresses caused by forced deformation were calculated for both sides of fixed straight tubes of 6 mm to 32 mm diameter. Simple equations relating the natural frequency and stress to diameter, length and displacement were derived. Calculation equation for the stress of a tube by the torsional displacement of the compressor at starting stage was obtained with a compressor and a straight tube model. Furthermore, stress of the tube at resonance was calculated using the mode shape equation and a simple equation relating stress to natural frequency and maximum displacement or acceleration. Tube design can facilitated through use of these equations relating frequency and stress of the tubes. Vibration transmission to the case and the noise caused by the vibration of the case will be discussed in a forthcoming report.

抄録全体を表示

Combination and supercombination resonances in a continuous rotating shaft with distributed mass are discussed. The restoring force of the shaft has geometric stiffening nonlinearity due to the extension of the shaft center line. It is considered that a distributed lateral force works. The possibility of their occurrences, the shapes of resonance curves, and internal resonance phenomena are investigated.

抄録全体を表示

An exact solution is presented for solving asymmetric free vibrations of laminated composite conical shells having meridionally varying thickness. Based on the classical lamination theory, equations of motion and boundary conditions are obtained from the stationary conditions of the Lagrangian. The equations of motion are solved exactly using a power series expansion for symmetrically cross-ply laminated conical shells. Conical shells having both ends clamped or the larger end clamped and the other end free are numerically studied. The effect of the number of laminae, the stacking sequence, the circumferential wave number and other parameters upon the frequencies and mode shapes of vibration are also studied and discussed.

抄録全体を表示

Car body and trucks of lightweight high-speed train tend to vibrate in elastic modes at frequencies higher than about 5 Hz, and sometimes their flexural vibration leads to the deterioration of the riding comfort. This paper presents a theoretical analysis on the vibration of a truck frame and a car body with flexural rigidity. The vibrations induced by vertical track irregularities are analysed using the transfer matrix method. Numerical results are compared with results of measurements made on the Shinkansen train. The results show that this method well simulates the vibration of a truck frame at high frequencies over 5 Hz compared with the classical method that disregards the flexural rigidity of the truck frame. Effects of the truck frame rigidity, the loss factor and the wheelbase on the vibration characteristics of truck frame are studied in detail, which leads to a conclusion that the rigidity of truck frame should be considered in the vibration analysis of truck at excitation frequencies higher than 10 Hz.

抄録全体を表示

In this study, a general method for analyzing the vibration of rotating anisotropic shells of revolution is doveloped. The basic equations, including the effect of the initial stresses due to the rotation, are formulated using the finite-element method. A shell of revolution is treated as a set of conical shell elements and the characteristic relations for the finite elements are derived from the energy principle by considering the finite strain. The equations of motion can be separated into the quasi-static and dynamic ones, i.e., the equations in the steady rotating state and those in the vibrating state. Normal concentrated impulses and step forces are used as the external dynamic force. The transient responses of truncated conical and partial spherical shells which have various degrees of anisotopy and lamination parameters are numerically caluculated.

抄録全体を表示

Active vibration dampers have been gradually used because they have the advantages of reducing the vibration drastically and adaptively. However, one main drawback is the requirement of large amount of energy. Vibration itself is one type of energy and an actuator is an energy converter, so the question arises as to how we can utilize this energy. This paper describes an energy -regenerative-type vibration damper. In this study, electric power is regenerated during high-speed motion of the actuator. For low-speed motion, an active or passive control algorithm is applied to the same actuator to achieve good damping performance. This method is applied to a single degree-of-freedom vibrating system with a linear DC motor. The system is simulated on a computer and a simple experiment is performed. The results show that the proposed system performs better than purely passive vibration control and can regenerate vibration energy.

抄録全体を表示

In this study we discuss the applicability of a high-damping rubber damper, which is composed of micro-networks and viscous material, as the damping device in microvibration-isolation devices or tables. For those purposes, damping force characteristcs of the high-damping rubber damper were measured using a new measuring device. We could estimate damping force characteristics to a shear displacement amplitude of 2.5×10^-6m, and this high-damping rubber damper was found to have energy-absorption capacity in the regions of very small shear displacement amplitude. Also, the damping force characteristics of a viscous shear damper using silicone oil, which is the most popular damper for vibration-isolation devices, were measured. On comparing the damping force characteristics, our high damping rubber damper was found to have a larger energy absorption ability than the viscous shear damper. Furthermore, the rubber dampers were installed to the vibration isolation table which can mainly isolate microvibrations in horizontal direction. Through microvibrationisolation tests it was confirmed that this high damping rubber could be applied to microvibrationisolation devices.

抄録全体を表示

Electrorheological (ER) fluid is applied to a controllable squeeze film damper for stabilizing a flexible rotor system. ER fluid is a class of functional fluid whose yield stress varies according to the applied electric field strength, which is observed as viscosity variation of the fluid. In applying ER fluid to a squeeze film damper, a pair of rings of the damper can be used as electrodes. When the electrodes are divided into a horizontal pair and a vertical one, the squeeze film damper can produce damping force in each direction independently. A prototype of the directionally controllable squeeze film damper was constructed and its performance was investigated in the present work. An artificial neural network was used as a control system for the damper so that it can be controlled even in the case that the charateristics of the ER fluid show strong nonlinearity or vary with time.

抄録全体を表示

Elastic parameters are essential for structural analysis. The elastic parameters of composite materials, however, are difficult to determine by either theoretical or experimental approaches. Therefore, an inverse analysis method to identify anisotropic parameters of composite materials by using FEM eigenvalue analysis is presented. A finite shell element for unsymmetrically laminated composites is formulated with the first-order shear deformation theory. As numerical examples, elastic parameters of composite shell structures are analyzed and compared with excitation tests. Equivalent stiffness parameters of a honeycomb sandwich panel are determined regarding as a simple shell with a low transverse shear modulus.

抄録全体を表示

Various one hand drive type wheelchairs have been developed for persons who can use only right or left arm. However, there was not an one-hand drive type wheelchair with a power assist function. So, in this paper, we propose for several mechanisms and control methods of such a wheelchair. Then, the simulation of linear and circular tracking control was performed for the proposed wheelchair. The result showed the validity of the proposed control method.

抄録全体を表示

A floating gear mechanism is often adopted in planetary gear design in order to share the load torque equally among planetary gears. The floating gear has no bearings and produces a self-centering nature. When the load torque is not applied, the floating gear lies at the bottom of the backlash area due to gravity, and it travels to the center position of the planetary gear train along several paths when the torque is applied. This path is called a self-centering locus. This paper experimentally and theoretically clarifies the self-centering locus, the relationship between the applied torque and the locus, and the minimum torque required to complete the self-centering process.

抄録全体を表示

In the low-noise current collector using a delta-wing-shaped collector head in which the aerodynamics becomes quite large, it is desired to develop an active control using a force actuator. This paper deals with the numerical calculations of aerodynamics generated by a delta-wing-shaped collector head and a pair of insulators. A variation lift was verified to generate clear in the experiment results of high-speed test train with a full size prototype current collector. The conclusions of this research using a new current collector are as follows;(1) In the simulation result of an active control generated the average lift at 160 N, it was verified that the contact strip has same characteristics of contact force at max. 70 N as the conventional one.(2) The variation lift of the collector head at 350 km/h is expected to be 80 N lower than that before improvement.

抄録全体を表示

To reduce noise caused by a current collector for the high-speed railways, a diamond shaped lownoise current collector has been developed. But it becomes difficult for this current collector to maintain the predetermined contact force between the contact strip and the trolley-wire, since its mass is three times as heavy as the conventional one and it suffers from ten times the lift force compared to the donventional one. So the vertical height of those apparatus should be controlled by using an active control system. The upper part of the insulator is located in high voltage which prevents us from using sensors. When using sensors only under the insulator, it is difficult to distinguish wire disturbance from lift one. In this study, the difficulty is solved by the H_∞ controller which separates those disturbances in the frequency range. In the numerical calculation and experiment using a prototype experimental equipment, it is confirmed that the contact force variation corresponding to the roughness of the trolley-wire at 2 H_z, 20 mm is reduced by about 70% compared with a passive model, and the contact force against the lift force at the ramp is reduced by about 30%.

抄録全体を表示

This paper deals with a discrete adaptive state feedback control method based on a strict positive realness and its application to a liquid transfer system. The proposed adaptive control system has a comparatively simple structure with conventional adaptive control systemS. First, we propose a basic construction of the adaptive control system under consideration with the feasibility of a control algorithm. Second, the proposed control method is applied to the iquid transfer system control problem. The control performance is examined from the point of view of the experiment. It is shown that the adaptive state feedback control is valid for the liquid transfer system in the case of variation of liquid mass

抄録全体を表示

Current control algorithms for antilock braking system (ABS) are mostly table-driven and should be frequently modified through various experiments, because the braking dynamics are highly nonlinear with system uncertaintieS. In this paper, a new control algorithm is proposed for ABS using the theory of sliding mode control based on a linearized system model, which represents nonlinearities as external disturbances. The proposed sliding mode controller guarantees a highly robust performance against large variations in the system parameters and disturbances. Furthermore, a road surface estimation scheme using a disturbance observer is proposed in order to determine the optimal reference input. Simulation results reveal the advantages of the proposed method in comparison with conventional linear controllers.

抄録全体を表示

This paper deals with a new design method for sliding mode control with frequency shaping. The concept is suppression of spillover phenomena for a flexible system. A conventional hyperplane consists of a desired reference model without dynamics. Therefore, the sliding mode control system often becomes unstable due to chattering and spillover phenomena in the high-frequency region. This method aimes to suppress a control input in a high-frequency region by filtering control input or measured output using a low-pass filter. The new sliding mode control system is designed as an augmented system which consists of a reduced-order model and a low-pass filter. We have applied this method to a four-story flexible structure. We have verified from simulations and experiments that this method has good performance and is very useful for suppressing spillover phenomena.

抄録全体を表示

This paper proposes a method to determine free design parameters in a feedback control law for slew maneuver of flexible beams. The feedback law is designed by applying Lyapunov's stability theory. The characteristics of the closed-loop systems are analyzed based on dimensionless equations and their relationship to free parameters are studied systematically. Results of the analysis and simulation suggest some guidelines on the gain determination. A numerical example shows that appropriate values of the free parameters can be found based on the proposed guidelines without trial and error.

抄録全体を表示

The objective of this study is to improve the servo stiffness and stability of the high-accuracy car level compensation device in a hydraulic elevator, which is used to reduce the car position fluctuation caused by passengers getting on or Off. The previous compensation device is composed of an electro hydraulic position servo system. In order to enhance this system, an observer is introduced to estimate the car acceleration, and a pseudo-acceleration feedback control is applied. The performance of the modified compensation device is examined by carrying our stability analysis and an experiment, and it is shown that the proposed control method halves the position fluctuation and quarters the settling time compared to the previous method.

抄録全体を表示

This paper presents a quantitative evaluation method for seat arrangements in commuter railway cars. The purpose of the study is to evaluate seat arrangements based on passenger comfort and accessibility, which are important during train operation. To determine the unknown parameters in the function, experimental examination was done. A full-scale mockup with variable seat arrangements was manufactured. It was modeled on a 20 m-long car with four or six doors per side, because a choice of the door arrangement is one of the main parameters. Using this mockup, comfort and accessibility were measured for ten types of seat arrangements. The results of the proposed evaluation functions using computer simulations agreed with measured experimental results. Applying the evaluation method to several seat arrangements, it is found that the most suitable seat arrangement depends on the average boarding time of passengers. From the evaluated results, suitable seat arrangements for commuter trains are discussed.

抄録全体を表示

The problem with 2D facility layout planning can be descrided as follows. Each placement unit is a rectangular block having various shapes and the purpose is to place all the blocks without any overlap, and to meet the given requirements for flows or closeness ratings between blocks as well as possible. This paper deals with applications of the genetic algorithm (GA) and the simulated annealing algorithm (SA) to such a combinatorial optimization problem. We clarify the effectiveness of new techniques for applying the GA or SA and the effects of some parameters on GA or SA performance, based on numerical experiments. These results let us determine the parameter tuning of the GA or SA. Then, we propose a new hybrid method combining the advantage of the GA for global searches and the advantage of the SA for local searches. After tuning major parameters of the method sufficiently, we compal^e the performances of the three methods proposed here. It is shown that the hybrid method has the best performance.

抄録全体を表示

In this paper, an approximately linear dynamic model of the ICPF actuator is proposed. According to the strategy in the last paper, linear modeling was carried out. A source of the internal stress for bending is the internal current since the speeds of both the bending and the internal current were the same. Moreover the magnitudes of both curvatures and simulational current were also in agreement with each other. The further the distance from the base was, the larger the curvature and the current were. To model bending motion to the cathode under a step input, an approximation that the internal current is differentiated with time before transferring to generarive stress was taken with a 2nd-order delay. The simulation results obtained using the above model agreed with the experimental results.

抄録全体を表示

In this paper, we describe the dynamic characteristics of a two link maniqulator which equipped with a passive joint and a low-rigidity link. This manipulator is composed of high-and low-rigidity tinks which are connected by a passive joint and an electromagnetic brake. The purpose of this structural feature is to harness the elastic strain energy of the low-rigidity link and the inertia of the system itself. >From the viewpoint of energy efficiency, the performance of this manipulator was evaluated analytically in terms of the energy efficiency index, i.e., the ratio of the kinetic energy of the payload to the work load of the driving motor. Also the carrier efficiency index was estimated as the ratio of the energy efficiency index to the working time required. As a result, in terms of working efficiency, this manipulator was compared with a typical two-link horizontal manipulator in various conditions of motion. It was clarified that the energy efficiency index strongly depends on the initial angle of the passive joint.

抄録全体を表示

The dynamics of an overhead-crane-type one link manipulator with a passive joint is essentially described by nonlinear ordinary differential equations including trigonometric functions. For a cart programmed to perform velocity controlled repetitive tasks, therefore, under certain conditions, the manipulator exhibits typical nonlinear phenomena, such as the coexistence of several stable periodic and chaotic motions. In this paper, periodic motions of the manipulator are studied numerically, and their bifurcation diagrams in several parameter planes are calculated using the algorithms based on the geometric approach of ordinary differential equations. The numerical results are also verified experimentally using a prototype manipulator. One interesting result is that steady states of the manipulator rotating around the joint, namely, periodic motions of the second kind, are observed in some parameter areas.

抄録全体を表示

This paper discusses the dynamic behavior of a pipe inspection robot driven by fluid force. The robot is composed of an inspection part, insertion roller, floats and cables to connect the floats. The robot receives not only drag force but also lift force through each float implemented in every link unit. Through simulation, we found that according to the shape of the pipe, there exists an optimum fluid velocity which provides the inspection position at the center of the pipe. Such optimum velocity is a function of mechanical impedance existing in the robot itself and the radius of curvature. We show a method which keeps the inspection part parallel to the pipe axis irrespective of the position of the center of the radius of pipe. We also consider the dynamic behavior of the inspection part under various parameters, such as the radius of pipe curvature, mechanical impedance of the robot, and the fluid flow rate.

抄録全体を表示

The motion of a robot arm subrerged in water is affected by added mass, fluid drag force and flow-induced vibration. The study, thus, deals with a technique for reducing these fluid influences on arm motion by ejecting air bubbles from the surface of the arm. Experiments are carried out using a two-degree-of freedom and two-joint manipulator. By ejecting air bubbles, we show experimentally a reduction of added fluid torque by examining the effects of arm acceleration, air ejecting pressure, and pattern on torque reduction. The following major results are obtained:(1)added fluid force to the robot arm acceleration in water is reduced by a certain pattern of air bubble ejection and air ejecting pressure and the reduction reaches a maximum of about 45% and (2)the relationship of added fluid torque reduction with air ejection pattern, air ejecting pressure or arm acceralation is experimentally clarified.

抄録全体を表示

The role of a robot is to save money and manpower in the real world. When the robot accomplishes this role to realize an autonomous function, unification of the system is a central issue. Hence, it is a subject to construct the control architecture as an unified method of intelligent control. Some research works about the error recovery ststem are carried out on manipulators, manufacturing systems, computer networks and so on. However, the hierarchical error recovery system has not been studied so much for autonomous mobile robots. In this paper, we propose a hierarchical control architecture HALAS (Hierarchical Adaptive and Learning Architecture System) as a control architecture for an autonomous mobile robot. The main feature of HALAS is the hierarchical error recovery function. We applied HALAS to an air conditioning equipment inspection robot. The validity of the proposed system is shown through some experimental results.

抄録全体を表示

In this paper, we deal with the problem of sensing information sharing among multiple robots in a Cellular Robotic System (CEBOT)-a model of the Distributed Autonomous Robotic System (DARS).Based on the analysis of the robot sensing actions in CEBOT, a distributed sensing for sharing which centers on information exchange and integration is introduced and discussed. By further analyzing the nature of the distributed sensing information, an approach for the integration of the distributed sensing information based on evidential reasoning is proposed. The proposed approach is examined through simulation using an application-Environment Map Building and Maintaining. The effectiveness of the Distributed Sensing in CEBOT centering on information integration is shown.

抄録全体を表示

In this study, the molecular structure analysis of myosin subfragment 1 (S1) is carried out using the molecular mechanics code "AMBER, " to characterize the structural morphology and the kinetic function. Using 3-D molecular structure data, which were determined by X-ray analyses executed by Rayment [Science, 261(1993), 50-58], the minimum energy conformations of S1 and S1 with ATP were obtained by molecular mechanics analyses. Differences in atom coordinates and potential energy distributions indicate local packing and heterogeneous characteristics of S1 structure. The normal mode and molecular dynamics analyses reveal the active sites of S1·ATP, and its kinetic function.

抄録全体を表示

In order to clarify the grasping mechanism of tools and handles, sensory tests have been performed and bio-measurements, i.e. electromyograms and measurements of finger forces, have been recorded. Feeling of the optimum diameter for holding cylinders had learning effect within 20 minutes; that is, the diameter increased after long-time grasping of the larger cylinder, while it decreased after long time grasping of the smaller cylinder. It was found that the optimum diameter determined by the sensory tests was that for long-time holding with reduced muscle fatigue and strong grasping force.

抄録全体を表示

The relative sliding movement between myosin and actin filaments is controlled by the troponin, which consists of three subunits called troponin-I, troponin-T, and troponin-C. Troponin-I inhibits this sliding movement, and troponin-C suppresses this inhibitory function under the calcium-ion binding state. In this paper, we investigate the function of troponin-C using the molecular mechanics analysis code "AMBER". The molecular structure data of troponin-C are provided by Sundaralingain et. al. [Science, 227(1985), 945-948]. Conformations in four cases, e.g., without Ca²⁺, with two Ca²⁺ in high-affinity site, with two Ca²⁺ in low-affinity site, and with four Ca²⁺, are determined by molecular mechanics analysis. The r. m. S. fluctuations and the isothermal compressibilities are evaluated by normal mode analyses and compared at N-domain, C-domain, D/E-helix, and troponin-C itself. Isothermal compressibility reveals the flexibility and the functional ability of troponin C. It is demonstrated that only when Ca²⁺ binds in low-affinity site does the D/E-helix twist very much and consequently, N-domain and C-domain approach each other. Our results reveals how Ca²⁺ induces troponin-C activation and it might concern to the kinetic function of troponin-C.

抄録全体を表示

We present a precise method of measuring the displacement of soft tissue using a probe with a compliant needle. The displacement vector is set using two needles which are fixed in the tissue. The new method was applied to measure the displacement of a porcine meniscus in the transverse plane under joint load. The meniscus moved 0.5-1mm outward under joint load of 600 N in 2 seconds. Then, slow displacement due to creep deformation followed. The results show approximate agreement with previous predictions by computer simulation and strain measurement.

抄録全体を表示

Human joints are subjected to dynamic or impact loading in life. However, conventional biomechanical research of human joints has been concerned principally with static loading condition. The purpose of this study is to investigate the mechanism of load transmission in knee joint under impact loading condition. In experiment with drop-tower impact apparatus using porcine knee joint, compressive stresses transmitted from femur to tibia through the knee joint were measured using small compresslye stress sensor inserted in cancellous bone. According to the experiment, a compresslye stress caused by impact load is much higher than a stress by static load. And an impact stress in the media1 side is higher than the one in the lateral side in knee joint.

抄録全体を表示

In order to realize high-speed positioning, we previously proposed acceleration feedback for a three-degrees-of-freedom fine-motion mechanism with piezo elements. Its superior performance was illustrated by the experimental results. In this experiment, a motional-mode-based decoupling control scheme was adopted. As is well known, the motional-mode selector and motional-mode distributor matrices, which are calculated using the displacement of both sensors and actuators, are inserted in to the decoupling control loop. However, it is difficult to determine these matrices uniquely. Thus, in this paper, a method to derive these matrices is presented which coincides with the initial condition of the compensator gain of an individual control system for comparison. In addition, the characteristics of motional-mode based positioning are shown in the experimental results.

抄録全体を表示

We proposed theoretical equations to clarify the effect of an electric double layer on the frictional properties of ceramics lubricated with water. Apparant increase of viscosity due to the presence of the electric double layer was considered in these equations. We found that minimum water film thickness increased with the zeta potential of ceramic in water. Also, friction coefficient decreased with the increasing of the zeta potential of ceramic. As a result, it was found that a large zeta potential in water is a suitable property for ceramic bearing material in water.

抄録全体を表示

The aim of the present study is to present improvements of mechanical seal performances for use under high-temperature and high-pressure conditions. Existing mechanical seals subjected to both high and low pressure show unstable leak rate and sliding reliability. We consider the deformation of pressurized seal rings by calculations and experiments, and derive the shape of a sea1 ring without tilting deformation from experimental data. We confirmed that this seal ring exhibits the stable leak rate and the sliding reliability under high temperature and high-pressure conditions.

抄録全体を表示

The overall objective of this study is to introduce a wear map of ceramics which shows the regions of dominant wear modes obtained in a wide range of materials and operating conditions. In the 1st report, it was clarified that the sliding wear mode of ceramics observed under various contact pressures, sliding velocities and temperatures can be classified into two types called "mild wear" and "severe wear" based on the ratio of worn surface roughness, R_y, to mean grain size, D_g, and specific wear amount, W_s. In this paper, the critical condition of the mild and severe wear is analyzed using an intergranular fracture model from both the view points of mechanical and thermal aspects, and a wear map of ceramics, which can define the regimes of mild and severe wear, is introduced; it uses two dimensionless parameters named as the mechanical severity of contact S_{c, m} and the thermal severity of contact S_{c, t,} as the vertical and horizontal axes, respectively. The availability of the wear map constructed in this way can be proved by the experimental results observed over a wide range of materials and operating conditions.

抄録全体を表示

With the aim of measuring local friction between slidng surfaces, obresvation was carried out in a solid contact state using an ultrasonic pulse reflection method. The reflection of ultrasonic waves at the contact boundary surface was dependent on the solid contact area, similarly to friction. Thus actual friction forces and the friction estimated from the height of the reflected echoes were consistent with each other. By comparing the fluctuation of local echoes measured using a focused probe with the measured value of friction which is the sum of the local friction forces, the estimation of local friction was realized, and using these results a distribution map of friction on a sliding surface was drawn.

抄録全体を表示

In this study, the wear characteristics of CFRP under the three-body conditions were investigated using a vibratory environment. An abrasive wear apparatus was operated based on the pin-on-plate method at the piston-reciprocated sliding friction. The vibrating action was induced by mean of a mechanical oscillator. The velocity ratio was defined as the ratio of the maximum vibratory velocity (aw) of the test piece to the sliding velocity X) of the plate. The amplitude (a) and the velocity ratio (aw/X) were varied to examine the influence of the vibrating action on the abrasive wear characteristics of CFRP. The experimental results are summarized as follows. (1) The wear rate of the high modulus type CFRP is greater than that of the high-strength-type. (2) In the abrasive wear of CFRP, no effect of fiber reinforcement is observed in the three-body abrasive wear. (3) In the vibration action in which the overlapping distance is 0.3 mm or less, the wear rate is independent on the vibration. However, when the overlapping distance is more than 0.3 mm, the wear rate becomes dependent upon the vibration.

抄録全体を表示

This study deals with the tribology of small two stroke cycle spark ignition engines fueled by methanol, gasoline and gas fuel. During the experiments, lubrication oil is supplied to the intake manifold separated from the fuels, by a carburetor. The degree of wear of each part of the cylinders was represented by the decrease in surface roughness along the sliding direction. Much decrease in surface roughness of each part of the cylinders is observed 10 hours after the start of running. It is shown that a part of a second ring of the cylinder at the top dead center shows a larger degree of wear than the other parts. The degree of wear of each part is dependent on the kind of fuel.

抄録全体を表示

This paper deals with the torque compensation cam (TCC)mechanism which minimizes the fluctuations of an input shaft torque. The principle of TCC is that the second cam mounted onto the input shaft produces an inverse torque which cancels the fluctuation of the input shaft torque. Because of this feature, TCC is considered as a good method for reducing vibration and for increasing the operation speed of mechanisms driven by a cam. Conventional TCC has considered only conservative force such as inertia force. However, for middle- or low-speed operation or some industrial applications, nonconservative terms such as friction or viscosity are of importance. In summary, a novel design methodology which can handle nonconservative terms such as friction and viscosity is developed. The peak torque can be cutoff and made constant by this method. As the result of the cutoff, the rated capacity of driving motor decreases.

抄録全体を表示

The formulas for displacement and velocity analyses are derived for a spatial four-link mechanism with two revolute pairs, a spherical pair and a cylindrical pair. Then, a procedure for determining instantaneous screw axes is presented and their behaviors in the neighborhood of limit positions are clarified. The condition for limit positions of the driving-link motion is obtained on the basis of force transmission from the coupler link to the driven link and the determinant composed of the coefficients of simultaneous equation for velocity analysis. The conditional function is investigated geometrically and a quantity is proposed in order to evaluate motion and force transmission characteristics.

抄録全体を表示

In the design of a planar conveying machine, individual links must be arranged separately on parallel planes, which are called layers in this paper, to avoid mutual interference among moving links during a cycle of motion. In the present study regarding a planar 6-link conveying machine, conditions which determine the minimum number of layers required for constructing the conveying machine are formulated. Moreover, in order to determine the optimum profiles of links which satisfy the minimum number of layers to avoid mutual interference among moving links, relative loci of pairing points and positions of links on the same layer during a cycle of motion are analyzed. Based on the results of analysis the planar 6-link conveying machine satisfying minimum number of layers is synthesized.

抄録全体を表示

The precision of products in plastic rolling bearings has been significantly improved by advances in molding technology and assembly technology. However, the idea that these bearings are still used only as miscellaneous mechanical parts is one of the problems that has not yet been wiped away. The reason why reliability has not yet been recognized is the lack of detailed reports about the characteristics of these bearings capable of supporting designs as data. Therefore, in order to define the operating characteristics of the latest plastic rolling bearings, the coefficient of friction of plastic ball bearings has been clarified in this report. Also using similar experiments carried out on steel ball bearings, the results have been compared and investigations have been carried out regarding practical use of plastic rolling bearings as mechanical parts of copy machine and so on.

抄録全体を表示

A precise analysis has been made for a design method in order to obtain a profile of the cutting edge of a hob, especially in the case in which a profile of the relief grinding wheel is given as a series of dispersive points. Firstly, it is clarified that under certain circumstances a singular point (a cusp) will occur on the profile of the cutting edge of the hob corresponding to the profile of the relief grinding wheel. Secondly, numerical analysis methods are proposed to determine the interference by using a conditional equation of the cusp and to obtain a profile of the cutting edge of the hob. Then, the theories in this analysis are verified by applying these numerical analysis methods to the dimensions of screw rotor hobs and relief grinding wheels.

抄録全体を表示

A method is proposed for achieving a topological tooth profile using a conventional grinding machine which cannot feed a shaving cutter toward the face width direction and generates an involute form by pitch band and pitch block with offset from the center of rotation. The first report showed an analysis method for generating shaving cutter profile by a conventional grinding machine based on a conjugate principle between grinding wheel and cutter. This report introduces a method of optimization in order to determine grinding machine setting conditions and cone grinding wheel profile which can generate a shaving cutter with the desired tooth profile. RMS value of the profile difference between ground cutter and defined cutter is adopted as the objective function for optimization. By analyzing a helical gear with bias modification, it is proven that the developed method can determine machine setting conditions and grinding wheel profile.

抄録全体を表示

Earlier equations for calculating the theoretical efficiency of planetary gear drives with two degrees-of-freedom produce great error in some cases. In order to eliminate the error, the authors derive new equations taking into consideration the effect of the coupling speed between the planet gear and the sun gear or the internal gear. These equations are derived using a simple law based on mechanics to meet the boundary conditions required for power flow in the drives. Numerical calculations are conducted using the earlier and present equations and differences in the efficiencies are shown for the case of representative planetary gear drives.

抄録全体を表示

It is important for the prevention of malfunction and accident due to by failure to detect failure in revolving devices as early as possible. The acoustic emission (AE) method is expected as means to detect leading to an abnormal phenomenon in revolving devices. Although research on gears using the AE method has been reported, little research has been conducted where the AE method is applied to running gears in a bending fatigue process of spur gear teeth. Therefore, in this report, with two micro AE sensors attached to the side of the gear, AE was measured in a bending fatigue process of a carburizing gear using a power circulating-type machine and AE source location in gear teeth was accomplished. By various analysis of the data, the AE characteristics in the fatigue damaging process of the gear tooth were determined.

抄録全体を表示

We report a grinding technique called the "arc envelope grinding method (AEGM)" and its grinding tests. In conventional form-generation grinding, loading and dulling of a diamond wheel can easily occur, which decrease both the machining accuracy and the wheel life, since the same part of the wheel is always used. In AEGM, a diamond wheel with a round profile is used and the workpiece profile is an envelope of a family of arcs. Since the grinding point is changed along the wheel profile with every grinding pass, the entire wheel width can be used and the wheel life is prolonged. In this study, arc truing accuracy, wheel design, surface roughness and form accuracy of the ground workpiece are investigated. Using the AEGM, nonaxisymmetric aspheric mirrors of silicon carbide were successfully ground. The form error after the first grinding (without any compensation) was less than ±0.8μm, and the roughness was R_max=0.2μm.

抄録全体を表示