This paper proposes a method for estimating natural frequencies of a disk tensioned by rolling without the use of eigenvalue analysis in finite element analysis. The natural frequencies of a disk vary when the localized plastic deformation by rolling induces residual stresses in the disk. That is applied to improving the dynamic stability of a circular sawblade and the optimum condition of rolling can be predicted using finite element method. In the proposed method, the natural frequencies of a disk after rolling are estimated from both the mode shapes of the disk before rolling and the stress distribution of the disk after rolling. This method is based on the similar idea of sensitivity analysis and requires eigenvalue analysis to only calculate the mode shapes of the disk before rolling. The effectiveness of the method is shown by comparing the natural frequencies obtained by the proposed method and by eigenvalue analysis in an example of the changing of rolling position.

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Filament-Wound (FW) formed highly anisotropic shell structures have recently been widely used in light weight applications as a space vehicle or a flexible manipurator. This paper discusses the influence of winding angle and lamination of FW forming on the natural frequencies for symmetrically graphite/epoxy laminated composite cylindrical shell simply supported at both ends. This free vibration analysis, which includes linear transverse shear deformation, shows that the fundamental or minimum frequencies are strongly dependent on the winding angle and value of shell geometry. The minumum frequencies are able to be higher with consideration of optimal lamination at various values of the shell geometry.

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Study of high viscosity type viscous damper design for crankshaft torsional vibration control is done here. The dynamic property of silicone oil is decided by the method of resonance peak distribution map. There is gotten the trace way on the map where the resonance peaks of crankshaft with viscous damper are located according to the variation of the temperature and the kinematic viscosity. Then, the optimum design area on the map is studied.

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If a domain of the target of analysis is convex, the solution of the two dimensional problem described by Helmholtz's equation is regular on the whole domain and the usual collocation method can be applied. On the other hand, if domains have notched boundaries, the tips of notches become singular points of the flux. For such cases, the solutions used in the convex domain problems can not be applied, because they never express any singularity. This paper shows that the analytical method for the convex domains previously proposed by the authors can be extended to the problems of notched domains. A general solution for the new method consists of two parts. One of them is the same as the solution for the convex domains and the other is a series that expresses the singularity at the notch tips. Numerical results of eigenmode obtained by this method satisfy boundary conditions and eigenvalues have excellent accuracy.

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Rubber engine mounting is usually used for a heavy duty trucks which have 4 engine mounting points. The purposes of its mounting system are as follows. (1) engine vibration reduction (2) body frame vibration reduction (3)supporting the engine weight and torque (4)power line noise and vibration reduction. In case of (1), the rolling mode vibration is most important because of the input torque from the engine crank shaft. So, the eigen value of rolling mode should be lower than 1/√(2)2 of the frequency of exciting torque. In case of (2), the power plant which is the combination of engine, clutch and transmission should be acted as the dynamic damper of the body frame bending vibration. For this purpose, the eigen value of the bouncing mode should have the same resonance point of the frame and a reasonable damping force. The first paper describes the differential equation of six freedoms and that of the dynamic damper. The comparison between theory and FEM is also conducted to confirm the accuracy of the simulation.

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The theory of a new experimental spatial matrix identification was proposed previously by one of the authors with a basic application. In addition, in this paper, its practical application to an actual mechanical structure is presented, since the authors think that it is important to investigate the practical validity and the usefulness of the identification method by its application to actual mechanical structures. The actual mechanical structure to be identified in this paper is an actual vehicle's chassis. In addition to showing this successful identification, some techniques to be considered for succeeding the identification are discussed with simulation based identification results: the identification of a vehicle's chassis model and cabin model, and the prediction of the dynamic characteristics of their assembly system.

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Horizontal restoring force of a multistage rubber bearing is affected by bending stiffness of stabilizing plate with which element rubber bearings are piled up. Horizontal stiffness of a multistage rubber bearing using stabilizing plates with smaller bending stiffness is smaller than that using stabilizing plates with larger bending stiffness nevertheless using same element laminated rubber bearing under same vertical load. This phenomenon is caused by decreasing horizontal stiffness of element laminated rubber bearings because of rotation of upper and lower edges of element rubber bearing. This effects was confirmed by combined loading tests of element rubber bearings. To estimate horizontal stiffness of multistage rubber bearings with various bending stiffness of stabilizing plates, we propose an analytical model for element laminated rubber which could trace reduction of horizontal stiffness by increasing of rotation angle of element laminated rubber bearing. Estmated horizontal stiffness and deformation shape of multistage rubber bearing agreed with the experimental results.

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This paper presents a dynamic analysis method for "Spaghetti Problem" using Multibody Dynamics technique. When a flexible body such as the thin plate or the paper sheet is pulled into the gap of elastic wall, its free tip vibrates most frequently near the entrance of that area. This phenomenon is observed on the rolling mill and the copy machine, and is called "Spaghetti Problem". The discrete beam model that is considered large rotation of bodies is assembled using rigid bodies connected with kinematically revolute joints and tortional springs and dampers that represents bending rigidity. The gap is modeled by the hard springs and dampers, on the assumption that it has the large rigidity in lateral direction, and suppresses the lateral displacement of the beam in it. The dynamic behavior of a thin plate is illustrated by numerical simulations with the presented method, and the dynamical characteristics of this phenomenon are examined by time history of total energy of the beam that is placed in outside of the wall. Moreover, the relation between driving velocities and magnitudes of their vibrations is investigated by its strain energy.

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This paper is devoted to the study of a stabilization for the parametric resonance of a magnetically levirated body subjected to periodically varying magnetic force. A pendulum, which is actuated under a proposed bifurcation control, is attached to the body. The dynamics of this control system is analyzed using the method of multiple scales, and the bifurcation set is derived from the amplitude equation. By the bifurcation control, the bifurcation set, i.e., the unstable region, is shifted and the parametric resonance is stabilized. Furthermore, it is experimentally verified that the parametric resonance is stabilized under the above control scheme. It is also clarified that this stabilization is effective on the passage through parametric resonance.

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Earthquake responses of rectangular water tanks should be investigated to keep water during disaster. Roof damage of rectangular tanks was reported in Hanshin Great Earthquake. In order to study sloshing impact effects on elastic roof plates, a sloshing test of using a multi-axes shaking table was conducted. In the test, the sloshing impact was measured in three roof conditions. The roof plate of 3 mm thickness was used in two setting conditions. One was clamped with bolts, the other was clamped with bolts and rubber washers. The roof plate of 13 mm thickness was clamped with bolts. Large roof deformation was measured in tests of 3 mm thickness roof. In the tests of 13 mm thickness roof, sloshing impact was measured bigger in comparison with 3 mm thickness roof. The results were discussed in theoretical analysis. Then, torsional sloshing motions were observed and discussed.

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This paper presents a theoretical study on the shock response of a contact recording head when a half-sine acceleration impulse is applied to the head-disk assembly system. The contact head is modeled by a cantilever beam with a concentrated mass at the tip. The surface undulation and the vibration of disk are both taken into account in the analysis. The contact force between the head and the disk is assumed to follow the Hertz theory. The head jumping height and the coiltact force between the head and the disk are studied in detail. The obtained results show that the maximum jumping height and contact force are significantly dependent on the amplitude and duration of the applied impulsive disturbance.

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We study the mechanical characteristics of the bounce phenomena in an electrical switching system. The electrical switching system, which is called a card-relay, consists mainly of an electromagnet, an actuator, a traveling contact and a fixed contact. First, the bounce phenomena, which include the impacts and the residual vibrations of both contacts, are investigated experimentally by measuring their velocitieS. Second, such bounce phenomena are examined theoretically using the governing equation in which the electromagnetic elastic coupling in the electrical switching system is considered, and the first and second vibration modes of the traveling contact are taken into account in order to evaluate its complicated behavior. Finally we clarify the feature of the bounce phenomena by comparing the experimental results with the theoretical ones.

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A System with a slide valve swithed by piston displacement is set in a horizontal cylinder. When gas is supplied constantly to the cylinder, the piston is moved to a certain position with damping vibrations. Then the slide valve is switched and the gas is ejected from the cylinder. As a result, the piston returns to the initial position, where the slide valve swithed again. The gas is supplied constantly to the cylinder. Thus the above procedure repeated. The behavior of the piston motion can be written by a set of linear equations with four parameters. The calculated piston motions are classified into smaller and larger effect of inertia, and they show chaotic features depending on the parameters. The effects of four parameters are examined.

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In this paper, a disturbance rejection problem of an automotive active suspension is formulated as an l₁ control problem. i.e., minimization of the effects of disturbances in terms of the l_∞-induced norm. Since l₁ control theory minimizes the maximum possible amplification of signal magnitude, l₁controller can specify the maximum magnitude of outputs in the time domain, regardless of the frequency of road disturbances. Shamma's l₁ near-optimal control theory is applied with a certain approximation. To design a simple static full state feedback controller, a nonlinear controller is designed for a linear active suspension model of a quarter vehicle. Finally, satisfactory performances are confirmed by numerical analysis.

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In a drop mass test, in which a weight falls onto a piece of silicon gel, the displacement and acceleration of the weight have been measured. The amount of energy absorbed by the gel is determined by the mass of the weight times the area, enclosed by a curve drawn by the data on the displacement-acceleration plane. In this convenient method to study energy absorption properties of such materials, contamination of noise is unavoidable due to its experimental set Up. In this paper, we show that wavelet analysis can be used to reduce noise in a simple way, and to effectively extract information contained in the data. The cut off level is determined by the assumption that the underlying data is expected to be reasonably smooth. We discuss the validity of our method and the reliability of the results. We also discuss that the phase characteristics of the mother wavelet, rather than the cut off characteristics of the associated filter, may have strong effects on the smoothed data, and hence on the determination of the energy absorption.

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This paper is a study on the valuation and mathematical formulation of human touch sensation. First, the feelings of touch are collected on five natural and chemical fabrics through the SD (Semantic Differential) method questionnaires sent to twenty three examinees. The feelings are valued on each fabric by using the weigthed mean on graded factor feelings. The multiple regression analysis is then introduced to represent the overall evaluation of touch on every fabric by a linear function of the valuations on feelings of touch. Next, a soft tactile sensor made of a PVDF (Polyvinylidene Fluoride) film patch and rubber layers is assembled and slid over the same sample fabrics to collect the surface tactile information on the fabrics. The features on the collected data are then extracted by calculating the temporal average of absolute out signal and using the intensity of power spectral density on the medium frequency range. Comparison of the results show that the PVDF sensor well describes the tactile perception of forefingers.

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When a light weight manipulator is moved quickly, the arm may bend and the control performance deteriorates. Such a manipulator must be modeled and controlled considering the flexibility. We propose a robust control design method for both the nonlinearity and high order modeling error caused by the arm flexibility. The control performance is evaluated based on the L₂ induced norm and an optimization problem is introduced. The feedback gain is solved by using LMI framework. Experimental results show the efficiency of this control system.

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Sliding Mode Control (SMC) as a Variable Structure System (VSS) and a nonlinear robust control theory, has been widely used in various engineering fields today, and carried out excellent performances in practical use. The purpose of this study is to make a try of utilizing SMC for hot strip finishing mill and present the datails of design procedure of discrete time sliding mode servocontroller. The plant is described as a MIMO system and the thickness measured dead-time is added into state space as a series of delay elements. The influence of this dead-time can be cancelled with the use of an augmented VSS observer. A state predictor also is used to compensate the time delay caused in calculation and transmission of control computers. A new approach of discrete sliding mode control which can remove the chattering phenomenon entirely, is proposed with the use of linear reaching law. The usefulness and robustness of the SMC are demonstrated through computer simulations under plant perturbation and external disturbances, and compared with a conventional optimal serve-controller.

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Hysteresis characteristics between the applied voltage and the displacement of the element is a big problem in tracking control of piezoelectric actuators whether position feedback is available or not. In this paper, we propose a new method to compensate such hysteresis taking notice of the linearlity between the displacement and the total charge on the piezoelectric element. We'd like to call this method' softwared charge control' in the sense that no hardware equipments are used in contrast to the conventional charge control.

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In this paper, impedance control of micro-macro robots in the presence of link flexibility of the macro arm is considered. Two control strategies for both the micro and macro arms are proposed. The control strategy of the micro arm is developed to obtain the desirable dynamic characteristics of the end-effector such as that of mass spring dashpot. The partial dynamic decoupling approach is adopted to reduce the link flexural effects in the dynamic behavior of the micro arm. The desirable moment of inertia, damping, and stiffness terms are designed in the task space. The control scheme is derived to guarantee the desired end-effector characteristics. In the control strategy design of the macro arm, a joint trajectory tracking control scheme is derived. Link vibration control input is added to the joint control scheme. Stability of the whole system is demonstrated using the Lyapunov stability theory. Simulation examples illustrate the effectiveness of proposed control method.

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This paper deals with adaptation, evaluation, and learning for fuzzy based intelligent robotic system. The intelligence of a robot depends on the structure of hardware and software for processing information, that is, the structure determines the potentiality of intelligence. Based on perceptual information, a robot with structured intelligent makes action from four levels in parallel. In addition, the robot generates its motion through the interaction with environment, and at the same time, gradually acquires its skill based on the generated motion. In this paper, We focus on a mobile robotic system with fuzzy controller, and propose a sensory network as perception ability for the mobile robot. We discuss the effectiveness of the proposed method through computer simulation result of collision avoidance problems for the mobile robot.

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This paper proposes a sensor-based navigation algorithm for mobile robots using information of target direction. The mobile robot moves from an initial position to a desired target position in obstructed environment by the navigation algorithm, where the robot does not know positions and shapes of obstacles, but only knows local information on obstacle's wall and target direction by it's sensor. The algorithm uses target direction instead of robot's position information which is used in other sensor-based navigation algorithm. This navigation method has robustness on the measurement error of target direction, while other navigation algorithms may not be able to work if the robot's position has measurement error. The main point of the algorithm is using the rotational angle of the robot based on topological characteristic of obstacles. Some simulations using the sensorbased navigation algorithm show an effectiveness by comparison of the proposed method and a conventional position based algorithm. Experimental navigation system using the proposed algorithm is developed for confirming the validity of the simulation study.

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This paper deals with cooperative transportation by a group of car like mobile robots regrasping an object. The authors propose the following approach: (1)designing a robot hand system, end-effector with compliant passive joint set up with offset: (2)robot motion planning by optimizing under constraints of available torque limitation that can be applied to an object. This end-effector enables us to avoid complications with motion planning because of non-holonomic characteristics. It also enables cooperation among robots that have errors in positioning. And torque limitation is considered in order to prevent slipping between the wheels and a floor. The effectiveness of the motion planning algorithm has been verified by transport simulations. Experiment shows that cooperative transportation can be realized.

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We developed inner skeleton type biped walking robot "ISR-1" to work as cooperating with a human being and instead of a human being. Force sensors installed in the actuator of ISR-1 measure the outside forces, which realizes the relaxation motion similarly to muscle of a human being. This system is composed of the easy mechanisms. When a relaxation motion works, there are characteristics that a restraint problem on the angle of the joint in double legs supporting phase is dissolved. This robot repeats stepping motion by the center of gravity movement for the robot on lateral plane. And swinging of the leg is added to this stepping motion and a walk action is done. This paper deals with walking control algorithm by sensors and the relaxation motion of the actuators.

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This paper describes a graphical method for analyzing a planar enveloping grasp by multifingered robot hand. The duality between form closure and force closure for the enveloping grasp is derived from the theory of alternative. The graphical method for deciding whether the enveloping grasp is force closure or not is proposed. The method is derived from the fact that the object motions in plane can be viewed as the rotation around the instantaneous center of rotation. The quality of the enveloping grasp is also discussed using the proposed method.

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This paper deals with the evolutionary design method of morphology and intelligence in autonomous mechanical/robotic systems. A robot performs a given task in a realistic virtual world including physics such as gravity, collision and friction; and receives fitness according to its performance. The robot which gained the higher fitness through genetic programming (GP) operators such as crossover or mutation evolves to a reasonably optimal morphology and intelligence. Thus the robot which is generated by this method will be a highly flexible robotic system because of its survival from the change environment including the uncertainty of real world. In this work, the robot is given three kinds of task which are specified by the number of object to be picked up and the task time. Various morphologies and interesting intelligence are emeged according to the difference in the task imposed. We examine the relationship between its morphology and intelligence and show the capability and flexibility of these evolutionary robotic systems.

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Identifying and implementing high fidelity feedback in scaled teleoperated systems is still a challenge. We propose the use of tactile information to complement and supplement the normal visual and force channels and thereby provide sensory enhancement when performing tasks involving delicate motions. We support our proposal by presenting experimental results from tests performed by humans on a simulation and experiment. Our results show that integrating tactile feedback improved the performance of the operator.

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This paper discusses stability of 3-D grasp considering rolling contact using potential energy approach. The synthesis of stable grasps is made by three-dimensional virtual spring which is fixed at the center of the fingertip. One spring is parallel to the normal and the others are parallel to the tangent plane at the contact. The kinematics of rolling contact equations (velocity and acceleration) between the object and finger are derived. Then, the stiffness matrix of the grasp is established. The derived stiffness matrix has six terms. The first three terms are due to stiffness of the three virtual springs respectively as well as remaining terms imply rotational stiffness which are influenced by curvatures, initial contact forces and contact position. The inverse problem, which is to determine the spring stiffness from the positive definiteness of stiffness matrix of the grasp system, can be also derived. Finally, some numerical examples are presented to illustrate the nature of the equations.

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As a power source for practical micromachines such as in-pipe mobile micromachines using fluid power, micropumps having high power density are required. In this paper, a piezoelectric micropump using resonance drive is proposed and developed. It basically consists of a bellows as a flexible pump chamber with an additional mass, a piezoelectric actuator for oscillating the bellows and cantilever type of two check valves. Firs fly, an effectiveness of the proposed micropump is confirmed through a fabrication of the large model and basic experiments. Secondly, a micropump with the size of φ9x10 mm for practical application is fabricated. Next, frequency characteristics and load characteristics of pressure-dependent flow rate are experimentally investigated with various structural parameters for optimal design. Through those experiments, the optimal amounts of additional mass and valve thickness are experimentally obtained for stable and high performance of the micropump. The maximum flow rate of 80 mm³/s, maximum pumping pressure of 0.32 MPa and maximum power of 8.7 mW are obtained at the driving frequency of 2.0 kHz. Also the feasibility of the piezoelectric micropump using resonance drive is confirmed through a comparison with conventional micropumps on maximum power density.

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This study investigates the possibility whether protozoa can be treated as a living micro manipulator/actuator or not. Motion control of protozoa is made by using the negative galvanotaxis. First, basic property test for DC electric field showed that Paramecium can control its motion by the electrical potential gradient. By using the 8 direction carbon electrode pool (electrode distance: 4 mm, thickness: 0.2 mm), operator can control the Paramecium to the aiming direction. Automatic motion control of protozoa was also achieved by using the image processing technology and fuzzy control method. These facts show that protozoa is able to use at a micro manipulator.

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When developping a fuzzy diagnosis system for machinery condition diagnosis, fuzzy relation between failure symptoms and failure categories must be defined for fuzzy inference. However, it is not easy to search out the failure symptoms by which all failure categories can be distinguished perfectly and automatically. In order to resolve the problem, we proposed: (1) a new type of symptom parameter called "sequence typed symptom parameter", (2) the identification method of the membership function of the symptom parameter, (3) the algorithm of "sequential fuzzy inference" by using the symptom parameters and their membership functions for diagnosis. The efficiency of the above methods has been verified by applying them to the ball bearing diagnosis system and others. In this system of ball bearing diagnosis, the sequence typed symptom parameters are calculated by the "symptom goodness of fit" with spectrum analysis and the results of sequential fuzzy diagnosis showed the correct conclusions when inputting the field data to the system.

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This paper is concerned with the development of an artificial urethral valve for treating urinary incontinence, which is driven by shape memory alloy actuators. Three types of valves are assembled and their opening and closing functions are examined experimentally by using the urethrae of male dogs. The latest model is driven by the non-contact induction heating system using power transmission coils. It is found that all of them show good opening and closing functions. The energy to drive the valve is transmitted by using an implanted coil of which outside diameter is 60 mm.

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The compatibility problem for car-to-car frontal collision is discussed using traffic accident data and simulations of multibody dynamics. The accident analysis shows that the car with masses of 1150 kg is the most compatible in the current car population. The sports utility vehicle and mini car are found to be the most incompatible car types with high and low aggressivity, respectively. Using multibody dynamic program, the safety of the driver of mini car in crashes into a rigid wall and into a large car was analyzed to accomplish compatibility. The optimum restraint system in conjunction with high stiffness of mini car can be effective to accomplish the safety of this type of car in crashes into a rigid wall as well as a large car.

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This study deals with the problem of analyzing the phenomena of interference among parts of a machine in motion. Some machines cause interference because of their basic structure as well as of their superficial form. A previous report demonstrated that a machine causes interference in a motion when its basic structure realizes a certain relationship among the torsion numbers, that is, the numbers of relative revolutions to occur between links in kinematic pairs in the motion. This report presents a graph-based method of judging the realization of the relationship for multi loop structures. First, the basic structure and the torsion numbers are represented in a graph. Next, this graph is transformed through a series of several graphs into a graph, called the fourth pair graph, each arc of which corresponds to a set of kinematic pairs in the structure and has a weight: the sum of all the torsion numbers that are each related to a kinematic pair in the Set. It is graph theoretically shown that when the weight of an arc in the fourth pair graph is not zero, the above-mentioned relationship is realized. Hence, by calculating the weights, one can easily judge the interferential characteristics of the structure.

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Chain drive has some merit in mechanical power transmissions, when the center distance of driving/driven shafts is wide and/or the same direction of rotation of driving/driven shafts is desired. The running noise and vibration of silent chain with roll-contacting rocker pins is fairly lower than normal roller chain drive or silent chain with simple joint pins, but it is still large enough to be of problem. In this report, the kinematics of the meshing of silent chain with roll contacting rocker pins with mating sprocket of involute spur gear is introduced. The simulating calculation based on this theory shows that the radial positions of successive plates of the chain around sprocket is divergent, when some slight disturbance is given for the position of the meshing in plate. This instability in the sitting position of chain plate corresponds well with the measured state of chain noise radiation and observed sitting figure of plates on the sprocket. The main cause of the chain noise and vibration is clarified.

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In interferometry measurement, it is important to obtain a clear interference fringe pattern. High density of fringes in interferometric measurement of involute gear tooth induces noises in measuring signal and makes the analysis difficult. In this paper, a new optical system to obtain an interference fringe pattern of low density is proposed. A spherical concave lens is added in the optical path of reference beam to deform the curved figure of the phase of the reference beam over the CCD plane. Selecting the focal length of the concave lens inserted, the phase difference between reference beam and object beam becomes fairly small over the CCD plane and the fringe density of the interference fringe pattern becomes lower. The effect of this new optical system is investigated.

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Dynamic tooth load is a pair of forces, which operates at the meshing points of a pair of helical gears. It occurs as a primary reaction of the vibratory system to mesh exciting force. In this paper, two methods of calculating dynamic tooth load are proposed; one is based upon motion of equation reported in the previous report and the other is compliance method based upon a physical exciting model. Applying building block approach to this model, dynamic tooth load is described as an explicit equation. By studying this equation, mechanism in which dynamic tooth load occurs can be classified into six cases. And according to this classification, it is discussed how dynamic tooth load can be controlled. Finally, calculations are done for a simple gear shaft model, and the proposed strategy in controlling dynamic tooth load is shown to be valid.

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The contacting situation between tooth surface of crossed helical gears in engagement is geometricaly a point contact. Due to high contact pressure on the tooth contacting surfaces caused by point contact and further high sliding velocity of crossed helical gears, the load carrying capacity of crossed helical gears is very low. On the other hand, crossed helical gears have many important advantages, i. e., they are easy to produce and their engagement is not influenced by mounting errors, e.g., center distance error and shaft angle error. We carried out studies on the influence of tooth profile and tooth surface treatment as well as of lubricating oil on load carrying characteristics of crossed helical gears. In this study we found some ways to improve the load carrying capacity of crossed helical gears.

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This paper describes a basic analysis on accuracy inspection of involute cylindrical gears on a CNC type of gear grinding machine. The measurement principle of the present method consists of four steps which include: (1) feeding a touch-trigger probe fixed on the grinding head to a suitable position relative to the measured gear set on the table of the grinding machine; (2) rotating the table to contact the probe with the gear surface; (3) memorizing the rotation angle of the table at the contact position in NC apparatus of the grinding machine and then stopping the table movement; (4) repeating the measuring process for every measurement point in the gear surface. A simple and practical algorithm for computing the various gear errors, such as the errors of the tooth profile, the tooth trace, the pitch and the tooth thickness, based on the memorized data is established. The influence factors on measurement accuracy and their sensitivity coefficients are shown. This method is also applied for the other types of CNC gear cutting machine if the rotation angle of the table can be memorized.

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The vibration of rail type rolling guides with recirculating balls was studied. The test rolling guides were operated at a constant linear velocity and the vibration of a rolling guide itself was measured. In addition, an experimental modal analysis was performed on the bearing block of a rolling guide under a constant linear velocity. Experimental results showed that the main peaks appear in the vibration spectra is not affected significantly by the linear velocity and the occurrence of the main peaks is influenced by the preload and the vibration measurement point. Analysis indicates that the main peaks are caused by the lower rolling natural vibration, the higher rolling natural vibration, the yawing natural vibration, the pitching natural vibration, the vertical natural vibration, the first flexural natural vibration, the second flexural natural vibration, the third flexural natural vibration of the bearing block.

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This paper describes an investigation of ball bearing vibrations caused by passing rolling elements with the distortion on outer ring. The analytical model is constructed with the following assumptions: A constant radial force is applied on the shaft. The outer ring is deformed into oval shape. A moment is applied on the outer ring. The bearing vibration is generated by elastic distortion of balls, variable contact stiffness of balls and radial stiffness caused by the moment. From the analysis, the following results are obtained. The vibration is increased when the principal direction of the oval outer ring shape is equal to the axis of the constant radial force and the small moment is applied around the axis.

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When a small induction motor with ball bearings is running under no load, an abnormal axial vibration of the rotating shaft often occurs. This vibration was studied in order to elucidate the generating mechanism. The test motor was operated at constant temperature, and the rotating shaft speed was varied by changing the frequency of an inverter. The vibration was measured by an eddy current type gap sensor, and was analyzed by an FFT analyzer. From the experimental results and related considerations, the vibratory system and the exciting force and self-exciting force that act upon the system were examined. It is clear that the abnormal vibration is a forced self-excited vibration of the vibratory system with an axial nonlinear spring due to ball bearings.

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The application of hydrodynamic fluid lubrication theory is attempted to the porous thrust bearings with various hydrodynamic shaped axial end surfaces. The superior one within the hydrodynamic shaped axial end surfaces such as, PUMPIN, PUMPOUT, HERRINGBONE, TPDLND (Tapered Land) and HWB (Hydro Wave Bearing) are experimentally determined concerning lubrication characteristics. The measurements of lubrication characteristics such as, a friction coefficient, the temperature rise, floating height, floatation and oil consumption rate for estimation of life expectancy etc. are evaluated. In this research, the results of this application on the end surfaces of thrust bearings clearly showed considerable improvement over the conventional thrust bearings. Furthermore, this experimental study clarified the load carrying capacities and lubrication conditions of the respective shape of the axial end surfaces.

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In this paper, we investigated the influence of secondary factors, i.e. slip velocity, gas leakage from the edges of porous surface, thickness of restricted layer and the effective area of porous surface on characteristics of an externally pressurized porous annular thrust gas bearing which has a thin restricted surface layer. By Comparing numerically calculated results with experimental ones, it is found that the numerically calculated results which take account of secondary factors agree well with experimental results in the clearance region greater than 2 μm.

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The effects of factors affecting the occurrence of numerous shallow radial cracks, which are observed on the rubbing surface of cemented carbide rings composing mechanical seals, are studied by thermal and elastic plastic analyses taking into account the thermal stresses. The numerical results obtained have shown that thermocracking mechanism can not explain why cracks run perpendicular to the direction of sliding and that the dynamical action of a high contact stress together with a high tangential force plays a very important role in the occurrence of cracks. The effects of sliding speed and thermo-mechanical properties of cemented carbide rings on the generation of tensile stress are also investigated in the light of the comparison with the effect of the contact stress.

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The effects of the addition of TCP and stearic acid to synthetic lubricating oils, polyolesters (POE), polypropylene glycols (PPG), polyvinylethers (PVE) for alternative refrigerants were studied using two different friction testers together with hydrogenated coal-tar oil (TN), and paraffinic and naphthenic mineral oils. The effectiveness of the additives was significantly affected by the polarity of the base oils. For the oils without polarity such as TN oil, paraffinic oil and naphthenic oil the additives improved their friction and wear characteristics compared with the oils with polarity such as POE, PPG and PVE which hindered the additives from the adsorption to the rubbing surfaces according to their reactivity. Particularly POE with highest adsorption ability was not improved in friction and wear performance by containing TCP. In contrast, the wear and friction performance of PVE which formed a solidified film more easily than POE was considerably improved by containing the additives. Although solidified films formed could prevent the rubbing surfaces from the direct contact, they were broken at a high contact pressure. The addition of the additives to an oil forming a boundary film of a solidified film considerably improved the friction and wear performance, while the movability of the additives in the oil became poor resulting in suppressing to some extent the formation and recovery of the adsorption film.

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In case of high speed casting, the big mold level fluctuation caused by slab bulging occurred. This phenomenon can not be explained by the steady state bulging model, so we made new bulging model considering slab movement and carried out high speed casting test using pilot plant. The results are as follows. (1) We found the critical casting speed occurred mold level fluctuation caused by slab bulging. (2) In case of under the critical casting speed, slab bulging deformations between the support rolls were kept constant because of shell deformations fell in the range of elasticity. (3) In case of over the critical casting speed, slab bulging deformations between the support rolls were changed with slab movement because of shell deformations increased and fell in the range of plasticity. Change of slab deformations contributed to big mold level fluctuation.

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The twisting effects of wire in coiling on the pitch or on the initial tension are investigated. As a result, it is clarified to process pitch or initial tension by twisting wire under a suitable feeding condition without adjusting the coiling points. The direction of twist agrees with the winding direction of compression coils, and the more the angle of twist per unit wire length increases, the larger the pitch of coils becomes. On the other hand, the more the negative angle of twist per unit wire length icreases, the larger the initial tension of coils becomes. And it is clarified that the highest level of the initial tension can be attained by the wire twisting method. If the initial tension varies monotonically in an extension spring, a new type non linear spring property can be attained. The wire twisting method is also useful to produce such a non-linear spring. Therefore the relation between the non-linear spring characteristics of the formed coils and the twisting conditions of wires have been studied. The experimental results agree qualitatively with the theoretical ones.

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A new milling head, which is able to control both cutting force and its locus, is proposed. The head has two helical milling cutters, which rotate in opposite wise through a pair of gears. Since both up and down cuts are carried on by each cutter at the same time, the sum of both cutting forces results in decreasing the resultant cutting force acting on the head and in changing the force vector locus. The force features by the head under selected cutting condition are numerically simulated through the cutting performance of single helical milling cutter with the energy approach method using two dimensional cutting data and experimentally discussed. The force and its locus can be controlled by the ratio of the up/down radial depth of cut and cutting edge phase.

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This paper describes the mechanisms of chip formation, chip removal from cutting edge and chip exhaust out of drilling hole of the twist drill drillable deep hole under continuously high feed rate. The web of this drill is three times thicker than that of the conventional one. Then the flute is nallow. The chip is a conical helix type at first, succesively changes to segment type, and then to a long pitch helix type. The segment type chip lines up in the flute and the long pitch helix type chip is along the flute. So, the segment type chip and the long pitch helix type chip are exhausted out of the drilling hole very well. While the depth of hole is still shallow at the beginning of deep hole drilling, the conical helix type chip is scarcely constrained by the flute. The hole becomes deeper, the chip requires larger area to grow and are constrained by the flute. Then, both moment and frictional force are applied on the chip by the flute and the drilling hole, and the cutting ratio changes. When the workmaterial has enogh plasticity, the chip changes to the long pitch helix type chip due to large oblique angle of the first main cutting edge. When its plasticity is poor, the chip becomes the segment type chip. The segment type chip is same as the head of the long pitch helix type chip.

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