This paper deals with an analysis of water hammer induced by instantaneous interception of a stationary flow in an elastic pipe. The analysis is based on the Laplace transform and the theorem of residue. The membrane theory of a cylindrical shell is used to describe the motion of the pipe wall. The fluid is regarded as inviscid. Among innumerable modes of the coupled waves of the pipe and the fluid, only two …are considered in the analysis, because they are the most important ones. Numerical calculation is executed for two types of boundary conditions. In the case that a valve is placed at a movable end of the pipe, the time history of pressure change becomes very complicated because of the longitudinal motion of the pipe.

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Steady vibration s of a bowed string are investigated by adopting Timoshenko's beam theory and the Voigt model for flexural rigidity and internal friction respectively. At the same time, the effect of compliance and damping of bowing action is taken into consideration. The rotary inertia, shearing displacement, internal friction and compliance with damping of bowing action are shown to cooperate to mitigate the bad effects of inharmonicity due to flexural rigidity.

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A method based on sensitivity analysis is presented for identifying the moment of inertia, spring constants and location of the center of gravity of a rigid body system supported by springs. This method is used to examine a technique for determining spring constants, spring locations and their arrangement so that the desired natural frequencies can be in tune. Further, the moment of inertia and the location of the center of gravity are identified from modal parameters measured in a vibration test model. The results of this investigation will be valuable in applications to vibration-proof-foundation design.

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This report deals with dynamic system identification which is based on two-dimensional autoregressive (AR) model fitting. The method proposed basically utilizes mapping correspondence between modal parameters shown in a z-transformed plane and those in a Laplacian (s-domain) plane. In order to reduce computer consuming time, the EFFT algorithm by Gan is introduced, and satisfactory time reduction can be obtained. As a practical application of the method, the time-dependent behavior of vibration parameter for the robot arm structure is identified and represented by trajectories in the s-characteristic plane.

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Metal flexible couplings are widely used in connecting shafts of rotating machines, since they have a simple structure, need no lublication, accommodate large misalignments of shafting and so on. However this coupling inclines to generate an axial vibration because of low axial stiffnesses of metal flexible plates. In this paper an experimental apparatus composed of a driving motor, a metal flexible coupling and a driven shaft, is constructed in order to investigate characteristics of axial vibration of the coupling under various conditions. The thickness and the number of flexible metal plates are varied in four and three levels respectively and the three different misalignment (axial, parallel, angular) conditions are considered. Further a formula for evaluating the axial stiffness of the flexible plate is theoretically derived, and the natural frequency calculated from this formula is in good agreement with the experimental one.

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A theoretical and experimental study is presented for the damping of circular plates by constrained viscoelastic layers when only a concentric portion of the plate is covered. For the flexural vibration of the plates, the equations of motion are derived by treating the in-plane displacements of the base and constraining layers as being independent, and by taking account of the in-plane force and displacements of a homogeneous part. The solutions of the equations of motion are given in a form of superposition of the solutions of the flexural vibration and the static in-plane deformation. Loss factors are determined by evaluating strain energies. Both theory and experiment show that partial coverage can give almost as much damping as full coverage.

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Deflectional and torsional modes of a beam may be coupled by nonlinear terms for large amplitudes. As a problem of deflectional-torsional vibrations coupled by nonlinear terms, the dynamic response of a beam with a thin rectangular cross section subjected to harmonic excitation in the lateral direction is taken up. The possibility of a multi-mode response between deflectional and torsional modes is discussed theoretically. For this, first a general analysis is given. Then, a typical case is taken up in which the natural frequency of the second deflectional mode coincides with that of the first torsional one, and a numerical calculation is conducted near the primary resonance point. It is shown that, in addition to the usual harmonic oscillation, two types of oscillations accompanying torsional modes are possible, whose amplitudes decrease in one type and increase in the other, as the excitation frequency increases. In this way the occurrence of the multi-mode response is ascertained. An experimental analysis is also conducted, which confirms the validity of the theoretical analysis.

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This study deals with the steady response of a beam with support inserts having material damping, including the effect of rotatory inertia and shear deformation. The Timoshenko beam theory is used and the displacements of a cantilever excited by the harmonic motion of the support are obtained. Numerical results are presented to show the effect of rotatory inertia and shear deformation and are compared with those obtained by classical analysis. The resonant frequencies obtained from the analysis are in fairly good agreement with those obtained by the experiment.

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An analytical estimation method is described for lateral vibration of piping system by the pulsation of containing fluid. The vibration of piping is considered as a forced vibration by the fluid force due to the pressure pulsation. The pulsating pressure and flow rate of containing fluid is estimated using the transfer matrix method. The vibration response of piping is then calculated utilizing model parameters of the piping vibration and the fluid force. The estimated responses on the pressure pulsation and piping vibration are compared with measured responses in both model piping system and actual high repsssure pump delivery line and it is found that the presented analytical estimation method has reasonable acculacy for practical use.

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An approximate method is proposed for the analysis of liquid containers considering the effects of the compressibility of the liquid. This method is based on the expansion of the vibration mode of compressible fluid-structure interaction using the coupled modes of incompressible fluid-structure system. Further simplified equations are derived assuming that the vibration modes are not changed when fluid compressibility is included. This paper also shows a technique to avoid the drawback of the mass matrix becoming the full matrix when fluid-structure interaction is considered. It consists of solving simultaneous equations utilizing the sparsity of fluid stiffness matrix without composing the full matrix in the subspace interation method for eigenvalues. Calculated natural frequencies and frequency response spectra, including compressibility of fluid, agree well with experimental results.

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A numerical method to analyze the free vibration of a pre-twisted cantilever plate is presented in this paper. The method proposed is based on the Rayleigh-Ritz procedure. Frequency parameters and more shapes of vibration for typical pre-twisted plates are computed and compared with results obtained by other investigators. The comparison shows that the method proposed is useful for analyzing the free vibration of pre-twisted cantilever plates. Then, the effect of pre-twist and the aspect ratio of plates on the free vibration is investigated.

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Control rod drop verification experiments of a pressurized water reactor under seismic conditions are performed to confirm the insertion function of control rods into a core. To evaluate these tests, computer simulations are performed. A fuel assembly, control rods, guide tube and other associated structures are immersed in a water tank, and shaken by four hydraulic shakers. The scram time of control rods under seismic conditions was measured, and confirmed to meet the scram function. Moreover, vibrational response characteristics of core structure and dropping behavior of control rods in consideration of collisions are calculated by using a finite difference method. The behavior of the dropping control rods and the scram time obtained by the computer simulation show a very good agreement with the verification experimental results.

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This study presents experimental results and theoretical analysis of squeal in the two-disks system, which is modeled after actual clutches or brakes. The system consists of a disk clamped along the inner edge and freed along the outer edge and a disk freed along both edges. It was observed that damping is more effective on squeal in high order modes. Thus the squeal frequency becomes lower as damping is increased. No squeal is generated when damping of two disks is over a limit in a state plane. To express the influence of damping on squeal theoretically, equations of motion with viscous damping terms are investigated and the characteristic equation is derived from them. Damping ratios of two disks have much effect on the squeal propensity which is a real part of the root of the characteristic equation.

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As engine block vibration contributes to engine noise, reducing the noise it readiates has become a major theme. Recently, radiated noise has been calculated on the basis of structural vibration data using BEM. Although there have been reports on radiated noise calculations, no literature reporting investigations of structural changes to reduce radiated noise has appeared. In this study, we investigated the basis of BEM to calculate radiated noise. We applied FEM to a rectangular panel model to analyze its vibrations. Using BEM we calculated the radiated noise from this vibration data. Next, in order to find a method for making structural changes, we applied the eigenmode sensitivity analysis method proposed by one of the authors. As a result we were able to reduce the noise pressure level radiating from the rectangular panel.

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In this paper, we analysed theoretically the hunting stability of a high speed railway vehicle which has at least seven degrees of freedom with respect to lateral motion when elastic and frictional forces are connected in series against truck turning. According to the theoretical results, it was found that the stability criteria of the hunting, so-called, "lower-center rolling", "upper-center rolling" and "yawing" of a car body, and the front and rear trucks depended on the lower hunting velocity was an unstable limit cycle, while the upper limit cycle changed into either a stable limit cycle or an unstable one corresponding to the magnitude of the angular amplitude. As the amplitude increased, the unstable region between the lower and upper limit cycles increased larger. Further, as the angular amplitude increased, the truck hunting phenomena of a bogie car connected with the damping of a suspension device between the car body and the trucks, the magnitude of the angular amplitude between the front and rear trucks, phase angle and others are made clear.

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Simulation analysis on the behavior of a gantry crane during take-off, load hoisting, load lowering and landing is performed for the strength of the crane. The theoretical results are in good agreement with the results of experimental tests using an actual crane. This shows that the dynamic behavior of the structure of a gantry crane against the load can be predicted. A new non-dimensional coefficient, "behavior coupling coefficient", representing the characteristics of a gantry crane is introduced. The numerical analysis using this coefficient suggests that a ratio between the vertical and horizontal deflections of the girder under loading is an important factor in the design of gantry cranes. Use of the coefficient also reveals the dynamic behavior of gantry cranes.

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This paper deals with the realization of a dynamic damper with a preview action proposed in the first report. It is also the purpose of this paper to verify the control effect of the dynamic damper for the suppression of a transient vibration subject to an impact force. First, this paper shows a mechanism of a newly designed dynamic damper with the preview action. Then, based upon three kinds of preview actions proposed in the previous papers, an impact experiment is carried out, verifying the effectiveness of these preview methods. Furthermore, an influence of the maximum impact force upon the control effect for the suppression of the first wave of the transient vibration is investigated. In addition, by varying preview conditions such as preview time and initial displacement of the damper mass, the control effect in terms of the preview action is considered.

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This paper described the relationship between some clamped forces and the stiffness and energy loss in a junction which were estimated and identified. One end of the beam which was oscillated by use of an exciter was clamped with two specimens. On analysis, Herzian and Mindlin's theories were applied to the sphere builed up by spring back on the asperity when a load was applied to and removed from the roughness. It is considered that the large asperity differ from the small one in the sliding ratio. The hysteresis loops were classified into three patterns. As a result, the tangential stiffness and the energy loss were expressed by two equations, and the tangential stiffness was given as a function of the displacement on the contact surface. The identification used the FEM (finite element method)and simplex method. The stiffness increased and the energy loss decreased with an increase in clamped force.

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Large space structures (LSS) will be constructed by linking flexible structures and so will easily undergo coupling vibrations due to disturbances. In this paper, a vibration control is proposed for such a linked flexible system by allocating actuators at the joint of the linkage between the adjacent flexible structure and controlling these actuators, so that the coupling vibrations should be decreased. In order to derive the dynamics of such a linked system, first a flexible structure with rigid bodies at each end is modelled by the bending vibration equation, employing the unconstrained mode method under the assumption that the linked flexible system vibrates only in a bending way. Then the proposed control method is applied to a flexible system for the experiment, which is totally floated by air bearings at joints, so that there is no reaction force from the ground to the floating joint and vice versa, unlike a robotic manipulator. Some experimental results are shown to demonstrate the effect of the proposed method.

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The equations of motion of a gear train system which is composed of flexible shafts, a pair of gears and an arm are derived in consideration of the torsion of the shafts, gear teeth stiffnesses, backlashes, and characteristics of a driving source. And, applying the minimum-time control method to the system in consideration of a natural period and amplitudes of torsional vibrations of flexible shafts, the dynamic characteristics of the system are analyzed theoretically and investigated experimentally.

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This paper describes an optimal starting and stopping motion control method without transient vibration for a multi-degrees of freedom flexible mechanical system involving dry friction as well as internal and external dampings. It is found that the effect of dry friction force can be approximately treated by linear analysis, if we assume residual compression of internal spring elements to oppose the friction forces at the entrance of constant speed region. The polynomial approximate solution presented in the first report is found to precisely coincide with the present strict solution in a high accelerating condition. Form experiments for a one degree of freedom vibration rotating system, marked validity of feedforward control for the flexible mechanism is confirmed.

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In this report, unstable vibration occurring in a hydraulic servomechanism controlled by a throttle valve when the feedback circuit of the system is closed is examined. It has been ascertained from the experimental and theoretical considerations that the unstable vibration observed in this experiment was caused by the coupling effect of the system parameters. This hydraulic servomechanism can be stabilized both by increasing the system rigidity and by decreasing the control valve mass. It is important that the system parameters must be established taking into consideration both the inconsistent demands on the control characteristics and the stability criteria.

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In a deaerator, which is used for the treatment of feed water of boilers, there have been rarely induced severe vibrations in the shell and spray valve. It has been considered that the vibration is self-induced by coupling between valves and shells. However the detail of the excitation mechanism of the vibration is not yet clear. In this study, the vibration of the value and the tank wall, pressure in the tank and the flow rate from the valve are measured experiementally through various contractions of the coil spring of the valve and thickness of the tank wall. By these experimental results, it has been concluded that the self exciting mechanism of the vibration is the pressure variation in the tank caused by vibrations of the spray valve and tank wall. Furthermore by the computation of the stability of this system, it is concluded that additional damping in the valve is very effective for the suppression of the vibration.

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Three dimensional sound fields described by the exterior Neumann problem of the Helmholtz equation are formulated. Application of the boundary element method to this problem is presented. Combined Helmholtz integral equation formulation (CHIEF) is adopted to overcome the numerical difficulty due to the non-unique solution at the eigenfrequencies of the associated interior Dirichlet problem. Numerical accuracies by the present method are examined with the cubic model circumscribed about a uniformly vibrating sphere. Sound fields radiated from a box with one or two vibrating faces are calculated and compared with ones measured in a nearly anechoic room. Results show that the effects of diffraction and interference on the sound fields are well predicted. Distributions of sound intensity level are also simulated.

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An approximate expression for multiple-edge diffraction of sound around a polygonal cylinder is derived based on Pierce's approximate solution for sound diffraction field around a hexagonal cylinder, which is also obtained experimentally through a sound visualization method using three color-light-emitting diodes. The hexagonal cylinder model used in this experiment has a circular aperture on its side surface and a speaker inside. A circular cylinder model is also used. It is, moreover, investigated whether the diffraction field around a cimcular cylinder may be estimated using the hexagonal cylinder inscribed in it or not. It is shown that the computed results agree well the visualized ones and that the diffraction field around a circular cylinder can be approximately estimated using the hexagonal cylinder inscribed in it.

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A new method for measuring the roundness of a cylindrical ground part is developed. The roundness is measured on a cylindrical grinder by a practical measuring apparatus which has two displacement detectors. The obtained signals are expanded in the Fourier series, and separated into the roundness and the error motion. The calculated result of the roundness agrees approximately with a result measured by a roundness meter. A cause of the difference is disagreement of three undulation spectra. A new method to separate the three undulation spectra into the roundness and the error motion is introduced, and the calcuilated results agree well with the results measured by a roundness meter. Consequently a possibility of in-process roundness measuring of cylindrical ground parts is indicated.

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In this report, a new measurement method of force and moment for robot applications is shown with the evaluation of experimental results. The force and the moment can be measured by using the characteristic such that the photo-trans-missivity of the photo-semiconductor (CdInGaS₄) changes according to the pressure applied on the semi-conductor : as the light radiated from the transmitter reaches the photo-diode through the semiconductor under the pressure, the output of the receiver gives a magnitude of force. under an eccentric load applied on the sensor, as light rays from the luminous-diode inclines, moments can be computed by measuring the eccentric projection deviating from the center of the quadrant of the photo-diode receiver. The experimental results show that this photo-semiconductor can be used as a new type of sensor for force measurement of a robot hand.

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In this paper, a method of force control applicable to robotic manipulations for manipulators and grippers is presented, with a consideration of the characteristics of objects based on adaptive control, by demonstrating experiments in a gripper system. This adaptive holding control method of a gripper, also applicable to any type of manipulator, whose control is based on the input-output position control due to the high reduction gear at joints, is shown so that it is possible to take into account the characteristics of objects which are brought about in the closed loop dynamics of force and position control. The gripper can hold objects adaptively with less impact forces against objects than before, hence it does not damage objects, unlike conventional grippers. Thus, the range of applicability of force control can be inceased much more with consideration of the characteristics of objects.

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The flexible functions of a human five finger hand with a palm are first studied from the viewpoint of force sensory manipulation, unlike the conventional viewpoint of position based manipulation. Then it is cleared that more than half of human hand work is related to force sensory information. Based on this examination, the degree of freedom of an articulated finger hand is determined to realize such a flexible manipulation as a human hand, so that twenty five degrees of freedom are necessary for a hand with consideration of joints inside the palm which have not been taken into acount so far. An Artificial finger hand with twenty five degrees of freedom is built for experiments by employing the wire and spring mechanism. Finally, an evaluation concept of three dimensional grasping is presented as a cross-section method by calculating applied forces and moments in a plane virtually cut arbitrary inclined angles around the center of a grasped object.

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To improve the accuracy of ratio control systems for control of air-fuel flow rate in combustors and internal combustion engines, etc., a new ratio control system with a fuel control device directly connected to an air flow metering element is presented in this article. A valve in a bypass air passage is controlled to keep the signal of the air flow metering element in the passage constant. The air flow rate is directly transfered to the stroke of the valve which is connected to a fuel control device. The characteristics of the system in steady and transient conditions was clarified.

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This paper describes modeling of torsional vibrations of flexible large space structures, such as solar battery arrays, and a control method based on this model. The torsional vibrations are modelled by taking into account the flexibility of the solar array and the inertial moments of the supporting rigid body based on the unconstrained mode method. Employing this model of the flexible structure, the system and the observation equations of the dynamics can be derived in the form of the state representation after N mode decomposition. The torsional vibrations can be measured by using a newly developed differential type of sensor, which consists of a pair of adjacent solar cells. A vibration control method is shown by the state feedback based on the dynamics. Some of experimental results employing the proposed control method are also shown.

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Actively controlled suspensions are required to realize a high stability and a high ride quality for high speed ground vehicles running on a rough surface. Recently actively controlled suspensions have been researched and developed for automobiles, railway cars and magnetically levitated vehicles. In this paper, optimal control systems for a two-DOF model of vehicle suspension are designed by optimal regulator theory, considering the dynamic characteristics of an air spring and a pneumatic actuator. Stability, ride quality and control input are discussed through frequency response and power spectral analysis.

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In order to achieve high speed driving and accurate positioning of a pneumatic cylinder, the optimal control method has been applied to a pneumatic servo-system composed of a cylinder, electro-pneumatic proportional valves of pressure type and feedback equipment. State and output equations for the control system were formulated and a quadratic performance function was introduced to obtain optimal feedback coefficients. Optimal regulators, namely control inputs have been computed by a microcomputer without any hardware controller using optimal feedback coefficients which are determined from Riccati's equation so as to minimize settling time of step response in positioning the cylinder. Experimental results show that positioning accuracy is about ±0.2 mm for optimal control and about ±0.1 mm for optimal control with integral compensation at a mean velocity of about 200--300mm/s. These results are compared with those of classical RI control. As a result, the optimal control method, especially optimal control with an integral compensator, is much better in controlled deviation and stability than the PI control method.

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In the previous paper, the deep-drawabilities of commercially pure aluminum sheets and mild steel sheets were studied in detail taking in account the change of r value during the processing. From the same viewpoint, this paper discusses the deep-drawability of commercially pure titanium sheets which have a crystal structure of hexagonal close-packed lattice different from aluminum and steel. The results are as follows : (1) The limiting drawing ratio, LDR, increases with the average r value (r^^- value), but the rate of increase ΔLDR/Δr^^- is relatively small. (2) The fracture strength correlates positively with the r^^- value, as in theory, but the maximum drawing load remains constant irrespective of the r^^- value, against theory. This relation can be connected with the result of (1), and resembles that of mild steel sheets. (3) The result of (2) can be well explained by the change of r^^- value due to equibiaxial strain and pure-shear strain, i.e., strain path dependence of the r value. The changes of r value are confirmed by texture analysis.

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Three principles for improvement of the square shell drawability can be summarized to be decrease in the drawing resistance P_max, increase in the fracture strength P_cr, and uniform distribution of these forces along the circumference of the punch shoulder. In order to achieve these principles, blank shapes (h_uni) are selected to obtain cup with a uniform height by means of the slip-line-field method. In the application of the slip-line-field method, the calculation starts from the drawn square shell having uniform height and is performed by going back stepwise the drawing process, and thus in this way finally the blank shape is determined. Therefore, this way can rid the troublesome trial and error process needed in the usual calculation. In comparison with a square blank, the h_uni blank improves the deep-drawability for all the shape factors r₁/l₁(r₁=punch corner radius, l₁=distance between opposite side). particularly, the improvement is remarkable in the acute corner radius.

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Scanning acoustic microscopy has shown a potential for detecting a surface layer damaged by machining. In this paper, methods which quantitatively identify the extent of the damage are developed. A V(z) characteristic which is formed as an interference between the acoustic wave reflected from the specimen and that radiated by the surface wave is utilized for the identification. A layer thermally damaged by creep feed grinding was used for this study. First it was successfully demonstrated that the extent of the damage can be graphically generated on a CRT by the respective layers from the surface to the matrix. Secondly, the transmitting velocity of the surface wave was shown to be sensitive to the extent of the damage for a material with small dissipation. Thirdly, the total power of Fourier transformed V(z) was verified to evaluate the damage and to be strongly correlated with micro Vickers hardness for a material with large dissipation.

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The electrolyte descharge system where an electrolyte is provided from a nozzle and the machining is performed by a tool at the center of the nozzle is prepared. In this system, an onset of the machining under a thin fluid depth is possible, although a higher voltage than that in the previous system with an electrolytic cell is necessary. In the drilling of glass, a high voltage is obtained for a positive polarity compared with that for a negative one. Therefore, the removal rate is high and the taper of the machined hole is small. The supply of square wave DC brings an increase in the voltage and a noticeable improvement of the removal rate.

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An optimal planning method is proposed for the initial design of a plant, concerned with the determination of the scales and the numbers of constituent equipment. The optimal constitution and operational policy of equipment are investigated in order to minimize the total annual cost. This planning problem is first formulated as a mixed-discrete variable linear programming problem, by adopting discrete and zero-one integer variables indicating respectively the scales and on/off status of operation together variable of each piece of equipment are determined by the repeated application of the least squares method. Lastly, the optimal constitution and operational policy are derived numerically by using the extended branch and bound algorithm, and the validity and effectiveness of the proposed planning method is ascertained following the example of the optimal planning for a ship's energy supply plant.

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A thermal designing problem was studied for an electric resistance vacuum furnace of the continuous-type used for the high temperature sintering process of new ceramic materials. This furnace has many small cells, and the static heat balance relations among each cell was described mathematically by investigating the spatially three-dimensional heat transfer phenomenon in detail. Then, a thermal insulation designing problem was formulated as a nonlinear multiobjective optimization problem, and the set of Pareto optimal solutions was derived by adopting both the weighting method and the generalized reduced gradient algorithm. As a result, the thickness of the heat insulator was determined optimally for each cell by minimizing both the total volume of the insulator and the total neat loss from the furnace coincidently.

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In this paper we consider the allocation of buffer capacities in a serial, synchronized, automatic production line with buffer storages between adjacent stages. It is assumed that every stage has a geometric distribution of up time. The measure of line efficiency is the maximum output rate from the last stage of the line in the steady state which is referred to as production rate. First, we develop in this paper a new efficient method of calculation of production rate which is suitable for applying dynamic programming approaches. Then, we propose an approximate solution method for optimal buffer allocation so as to maximize production rate applicable even to long lines with many buffer storages and a large total buffer capacity by applying dynamic programming techniques. We confirm the validity of the approach by comparing the solutions obtained by the present method with those obtained by computer simulation for many example problems.

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The floating clearance between the floating head slider and the disk of large capacity magnetic disk files is becoming smaller and smaller, the present values being from 0.3 to 0.5 μm. To ensure reliability, dynamic characteristics of the slider subjected to disk vibration or run out must be predicted accurately. Finite difference methods or Divergence Formulation Methods have heretofore been used to obtain the dynamic characteristics of sliders, but difficulties have been met in treating complex shaped sliders. In the present paper, the finite element method has been used. The calculated results agreed with those obtained by the above mentioned conventional methods. They agreed with the experimental results obtained using a taper flat type slider with yaw angle. Furthermore, the dynamic characteristics of a grooved slider and a negative pressure inducing slider have been predicted by this calculation method. The present methods are so formulated to include the calculations of both the static and dynamic characteristics.

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A generalized lubrication equation valid for an arbitrary Knudsen number, ratio of molecular mean free path and spacing, is derived through a linearized Boltzmann equation. Numerical analysis of the equation reveals two principal results. First, a modified Reynolds equation based on first order velocity slip overestimates load carrying capacity, while the approximation equation including second order velocity slip underestimates it. Second, in the case of a high compressibility number, the difference between results from the generalized equation and the approximation equations are decreased.

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Highly accurate (minimum measuring separation 0.025 μm, accuracy 0.002μm), wide frequency range (dc to more than 100kHz) measurement of the separation of gas lubricated slider bearings is presented using visible laser interferometry. The new technology for realizing this measurement includes ; 1) elimination of undesirable interference patterns by adopting optics that focus the laser beam into a small cavity, 2) elimination of laser tube resonance noise, 3) automatic compensation for variations in the optical parameters. Experiments adopting this measurement are performed in an ambient helium atmosphere and the results are compared with numerical solutions based on the modified Reynolds equation. The experimental and numerical results have excellent agreement within the range of separation down to 0.025μm, and with Knudsen numbers as high as 8. As a result, it is confirmed that the modified Reynolds equation can be used to predict slider bearing characteristics accurately within the experimental range of separation and Knudsen numbers.

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A sphere falling viscometer using a diamond anvil high pressure cell reported in the former report is improved to measure the viscosity at an elevated temperature under high pressure. A standard liquid JS200 for viscometer calibration and a synthetic lubricant UNIVIS P12 are employed to evaluate the accuracy and reproducibility of this viscometric system. The viscosities obtained show good agreement with those of NRLM, and observed temperature and pressure ranges are two or three times as large as those NRLM. The viscosity-temperature relations obtained under high pressure can be expressed by Walther's equation, and are consistent with the Eyring model employing an absolute rate process.

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Many studies on tooth surface strength have been reported but they are mainly reports on tempered steel. So, it can be said that sufficient data to design the case hardened steel for tooth surface strength has not been published. Therefore, spur gears were tested for tooth surface strength under several lubricating conditions and several surface treatments of test gears. The tooth surface strength of case hardened gears is not so affected by the difference of the viscosity of lubricating oils, as are the tempered gears. The EP additive is effective for the tooth surface strength of case hardened gears but it is not effective for the tempered gears. The difference of the chemical structure of the lubricating oils has some effects on the surface strength of gears. The effective case depth of case hardened gears is an important factor to determine the tooth surface strength.

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Spiral bevel gears given both crowning and profile modification, mesh with each other at a point. Such gears can allow unavoidable errors during manufacture, but are non-conjugate gears in a strict sense. This paper is concerned with the gear cutting method of such gears resulting in a negligibly small non-conjugacy. In this method, the Gleason hypoid generator is used without any alteration. Gears with a tapered tooth height are cut without cutter tilt. A negligible small non-conjugacy is achieved with a slight modification of the cutter. The main procedure of this method is to determine THE MACHINE SETTING taking into account both the engagement of gears and the location of tooth bearings.

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In the first report, a new globoidal worm gear with a pin-wheel was proposed and its geometorical characteristics were examined. The gear has the merits of being easy to manufacture and maintain. This paper deals with machining and running of the gear. Two pairs of the gear were manufactured : the worm of case-hardened steel and the wheel having phosphor bronze pins. The reduction ratio was 1/24 and the center distance was 100mm. Running tests were performed at a worm speed of 1432 r/min. The worm gears can be operated continuously at an input power of 3.75 kW max. without any scoring. The transmission efficiency reached 80% under the maximum input power.

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An idle gear with a thin rim is replaced by an equivalent ring whose bending stiffness is equal to that of the idle gear. Then the radial, tangential and angular displacements of the equivalent ring are analyzed theoretically considering the condition of contact between the idle gear and the gear shaft. Further, the displacements of the equivalent ring are translated to those along the line of action in order to obtain the deflection of the rim of the idle gear along the line of action. Consequently the deflection of the idle gear is obtained by adding the deflection to that of a tooth which is widely used. The deflection obtained theoretically agrees comparatively with that obtained by the finite element method.

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A new method is introduced for calculating the shape of a gear hob for generating gears with an arbitrary tooth profile. This is applicable to calculate the shape of the tooth profile generated by a hob with an arbitrary shape of the cutting-edge. Because this method simulates exactly the metal removing process in gear tooth profile generation, it is possible to calculate the generated tooth profile when an interference occurs between the cutting edge and the finished tooth profile. As an example, the shape of the cutting edge of a hob was calculated for cutting cylindrical gears with a circular-arc tooth profile (Novikov gears). The profile errors produced in the calculation were less than 1 μm for gears with a module of 5 mm.

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By applying the theory in the 1st report, the authors proposed a method to calculate the exact profile of a form grinding wheel for finishing a helical gear with an arbitrary tooth profile. Using this method, they calculated the exact wheel profile which can produce an involute tooth profile with a tip relief at a transverse section of the involute helical gears. The wheel profile was generated by a single point diamond dresser using a universal NC milling machine with an attachment made by the authors. The tooth flank and root of test gears were ground at the same time to prevent occurrence of a notch which is apt to be produced at the boundary of ground and unground surfaces. The accuracy of the form-ground test gears was in the 0 class of JIS and their surface roughness was in the range of 0.5 to 1.0 μm R_max.

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