[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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A method of analyzing free vibrations of plates with arbitrary shape and boundary conditions is proposed in this report. The procedure presented is based on the Rayleigh-Ritz method using Lagrange multipliers. The deflection of plate is expressed by a double power series of x and y. Since this function, in general, does not satisfy geometrical boundary conditions, the Lagrange multiplier method is applied t fullfil them. The strain and kinetic energies are evaluated by a single integral along the edge of plates. The theoretical values obtained are compared with exact values and test results. The comparison shows that the method proposed is useful to analyze the free vibration of plates with arbitrary shape and boundary conditions.

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When a hanging articulated pipe is vertically excited in water, the dynamic behavior of the pipe is analysed as a dynamic problem of a system with parametric excitation and nonlinear damping. Though this system may become unstable under certain input conditions, a response may not diverge due to the fluid drag force being proportional to the squared velocity. In this study, the stability condition and responcse under an instability condition are analysed. A model experiment is also carried out to confirm the theoretical results, a simple equation between the response and the input is derived, and it is confirmed by the model experiment. A model experiment is also carried out t confirm the theoretical results. As a result, a simple equation between the response and the input is derived, and it is confirmed by the model experiment. It is seen that this simple equation if valid for small input nuder the conditions assumed in this study, and the response amplitude is proportional to the input amplitude in the case of the input frequency being twice the natural frequency of the system. In addition, the response amplitude decrease when the input frequency differs from twice the natural frequency.

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A water-lubricated bearing has the following characteristics : (1) turbulent flow, (2) full film due to high ambient pressure, and (3) large additional mass effect. These characteristics have not yet been fully solved. In this paper, the results are presented on cylindrical bearing characteristics, which are numerically analysed and tested using special test system.

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When an uniform beam is subjected to impulsive-like rotation, equations of motion in the axial and tranverse directions for the beam are derived from Halimton's principle, based on the Euler-Bernoulli hypothesis. By using of a linear elasticity and other assumptions, they are simplified and decoupled. An impulsive-like velocity Q(t) is given by Q(t)=Q₀[1-epx(-ct)] The fundamental equation is transformed into the finite-difference equation and it is numerically analyzed. The dynamic responses of the beam are obtained for the various values of c in the above equation. The variations of the deflection at the beam-tip with respect to time are discussed. The amplitude and period of the cyclic deflection at the beam-tip are obtained for c.

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This paper presents a method of the optimum design for journal bearings. That is, the object is to optimize the system in stability at the operational speed, unbalance responce in the vicinity of the rotor critical speed, frictional power-loss, and matufacturing cost of the bearings. The reference function is composed of these four objective elements and it is minimized by both selecting the bearing type and changing bearing diameters, lengths, radial cleavances, and pre-load factors. A simple rotor-bearing model considering the momentum of inertia is analyzed and its reference function is presented. Then optimum bearing type and dimensions of bearings are obtained.

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The aim of this paper is to analyze the dynamic behavior of a catenary-type overhead wire and a pantograph. Short-period separations between a pantograph and a wire occur frequently at high speed. They cause an electric arc and extensive wear of collectors and wires. A new mathematical model is developed in order to investigate the reasons for these separations and improve the dynamic performance of power collect systems. the wire is modeled using a beam with a tensile force and the pantograph by a multi-body system. The dynamic effects of hangers which suspend a wire discretely are also considered. Periodical contact forces are obtained by the Fourier-series method. The effects of the distance between the hangers and the pantographs are calculated.

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Displacement, velocity and acceleration of mechanism of an arbitrary type are analyzed numerically in order to simulate motion of an articulated robot. Uicker's method of analysis, based on the matrix algebra for a link mechanism of a closed loop, is extended to mechanisms of an opened loop and compound loops. How to judge a singular point of motion is explained. On each step of the iterative calculation for convergence by the Newton-Raphson method, a method is proposed to correct the angular displacement of the pairs. It is made clear that he proposed method of correction realizes the analysis of rapid convergence and of high accuracy.

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Static and dynamic forces which have to be applied to input pairs of an arbitrary-type mechanism against many kinds of actions are analyzed numerically, in order to simulate motion of an articulated robot. Uicker's method of analysis, based on the matrix algebra for a link mechanism of a closed loop, is extended to mechanisms of an opened loop and compound loops. the static forces necessary to compensate the forces acting from the outside are analyzed by the principle of virtual work. The static and the dynamic forces necessary to compensate the inertial force, the gravity force, the spring force and the damping force are analyzed with Lagrange's equation of motion. The forces of two kinds of the robot model are caluculated numerically by the present method and the results compared. Both results agree well with each other.

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The vibration of link mechanisms of a closed loop, an opened loop and compound loops is analyzed numerically, in order to simulate motion of articulated robots at the design stage. It is assumed that all parts of the mechanisms have linear characteristics against small displacements around the equilibrium positions. First, the equation of motions is composed with the inertia, damping and spring forces calculated in the authors' previous report. The natural frequency, natural mode and transfer function of the link mechanism are analyzed by this equation. Next, the displacement and the stiffness of the hand of the articulated robot are analyzed. The vibration of the actual robot for industry is calculated numerically by the present method under the assumption of structural damping. The damping and stiffness coefficients of each pair are determined by the basic experiment. The caluculated results are compared with the results of the vibration test.

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The authors developed a practical computer program to calculate the stationary sound pressure level by using wall or machine surface vibration modes and frequencies. This approach is named the method of superposed sound sources. In this paper, we first describe the theoretical background of this method, and next show that the numerical obtained results by this method agree with the experimental or analytical results. We can predict the sound level by using this approach.

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A forced cooling heat exchanger constructed of many fins with slits causes a discrete tone equally-spaced in frequency, depending on the air flow velocity. In order to calculate the natural frequency of the cavity, we made and analytical model, consisting of a main cavity, corresponding to the slits, and additional cavities attached to it at equal intervals, corresponding to the spaces between the fins. The boundary conditions at the branch points are the same pressure for each cavity and flow continuity. Wave equations and the boundary conditions define a difference equation. The frequencies and the modes deduced analytically agreed with experimentally-obtained results. We can predict the tones and silence them by using the analytical results.

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This paper presents preliminary studies on measuring method of torque in the rotating shaft by utilizing the magnetic lattice. The intensity of torque is proportional to the angular twist of the shaft. In this research, the relative angular displacement between two positions on the torsion bar can be detected from the phase difference between two magnetic sinusoidal signals, which are recorded on magnetic tapes winded on those two positions. The torque of the shaft can be calculated from the angular displacement. This method using the magnetic lattice may be possible to measure the torque in the wide range and with high accuracy, comparing with the usual torsion-bar torquemeter. Through experimental studies, it is clarified that the proposed method has sufficient validity to the measurement of torque for the rotating machinary and has the possibility of the practical use.

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A double-row admission gas journal bearing with partially gas-fed slot restrictors is investigated. In this type of bearings, gas flow is mainly restrained by both the viscous resistance in the slot region and the inflow resistance at the inlets of narrow feeding slits. Therefore, the maximum load capacity of this bearing can be obtained easily in a small bearing clearance less than 10μm. Here, influences of various design parameters on the static characteristics are described and the optimum design conditions and the usefulness of this type of bearings are confirmed by comparison with the experimental data.

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In this paper, the effects of fluid inertia forces in annular parallel plates squeeze film bearings lubricated with pseudo-plastic fluids are investigated theoretically. The cubic equation obtained from the empirical flow curves for the pseudo-plastic fluids is used as the relation between shear stress and rate of shear. Approximating the inertia term in the momentum equation by the mean value averaged across the film thickness the film pressures are obtained, and the effects of inertia forces on the films pressures are discussed for various nonlinear factors.

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The true root stresses of internal spur gears with various numbers of teeth and addendum modification coefficients are calculated by two-dimensional elasticity theory and mapping function and the position of critical section on tensile side of internal spur gear tooth is indicated. The stress concentration factors at the position of critical section are calculated under various on the basis of these calculated results. Furthermore the root stresses calculated by this practical formula are compared with those by FEM and measured ones, and the validity of the practical formula is confirmed.

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Some reports have been given on hobbing internal gears. But in all cases, the tooth generation with the hob has not been put in practical use because the problems lay in manufacturing of the hob. So the authors have made research on Spherical hob to solve the problems and succeeded in tooth generation. In this paper, we explain the method of spherical hob manufacturing and hobbing equipment remodeled for internal gear and describe the quality of internal gears. As the results of test hobbing, total profile error was 12μm. The profile did not change even if the hob was shifted or the setting angle of the hob was changed. As for the pitch error, maximum circular pitch individual error was 5 μm and maximum cumulative pitch error was 19 μm. These values mean that the hobbed internal gear has the highest accuracy.

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For the development of mechanical systems of high-speed and high-precision, a dynamic design theory with consideration of bearing clearances which produce a great influence upon the dynamic characteristics of the systems is strongly demanded. About a four-bar mechanism with clearances, the authors have already revealed that the separations between pairing elements can be predicted from an exciting force of a model vibratory system with a mass, spring and dashpot which is derived from equations of motion of mechanisms with clearances. In this paper, about a crank-and-rocker mechanism with clearances, three kinds of restraint methods of separations between pairing elements have been discussed with consideration of the conditions where the above exiting forces decrease or become constant. Especially, in order to obtain mechanisms with good dynamic performances, an optimum design method of the mechanisms with clearances has been discussed to determined directly shapes of moving links instead of their mass parameters.

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Crank-length adjusting mechanisms have been proposed in order to change input-output relationships of arbitrary planar, spherical and spatial crack mechanisms and also to stop output motions of crank-and rocker mechanisms during rotations of their crack shafts. Structures of the crack-length adjusting mechanisms have been obtained by a number synthesis, after analyzing the relationships between the crank length and the displacement of a moving pair on the crack in the case where the pair moves along a straight line or an arc fixed on a rotating plane of the crank shaft. Some applications of the mechanisms to adjustable path and function generators have been shown.

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This scheme and the previous report argued about an intelligent CAD in all processes from a conceptual to a detail design when design specification was imposed only in semantic, and the design of flanged shaft coupling was implemented actually. The equations and tables for calculation were stored in the form of so-called frame, and they should be picked up correctly whenever were retrieved. Some other devices were made upon a method how to specify each shaft for example, when two or more shafts existed, without loosing common character of shaft.

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finite waiting space in front of servers, we derive the system size distribution ( the state probability) and the mean number of customers in the system for two servers. Furthermore, a method of diffusion approximation is applied fro solving the system with general independent interarrival time and general service time distributions. Numerical examples for the mean number of customers in the system are given to compare an exact value with an approximate one.

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