This paper deals with the free vibration of continuous rectangular plates and the optimization of the fundamental frequency. Some of the complicated effects of material orthotropy, variable thickness and in-plane loading are considered in the vibration analysis. In the optimization process, the span length of line supports is used as the design variable, and the lowest frequency is maximized as the object function. In numerical examples. the optimal spans are thus determined for three span plates, and the effects of varying support conditions, orthotropy and in-plane forces are discussed.

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This paper deals with an approximate solution and instability for lateral vibrations of an asymmetrical shaft. When a rotating speed of the shaft fluctuates periodically with N times in a revolution, unstable vibrations occur at angular velocities near the major critical speed ω_c and near 2ω_c/|2±N|. In the cases that N=1, 3/2, 2 and 3, the approximation of the higher order than the first report is carried out for various values of an asymmetry of shaft stiffness Δ and an angular velocity fluctuation ε, and the effect of these parameters Δ, ε on the position and width of instability regions is made more clear. Then, the equations of motion are directly integrated, and loci of the shaft whirling are described in the x, y plane in order to know a dynamic behavior of a rotating shaft in instability regions. Furthermore, it is shown that very narrow instability regions occur at the angular velocities ω≒ω_c/N and 2ω_c/N.

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This paper deals with the self-excited vibration of a rotor completely filled with liquid. It is well known that a rotor partially filled with liquid undergoes self-excited vibration at a certain rotating speed, and that it is caused by the existence of the free surface of the liquid. In the present paper, it is shown experimentally that the self-excited vibration occurs even for a rotor completely filled with liquid, without any free surface. By visualizing the flow in the liquid, a secondary flow, large vortices, like the Gortler vortex, can be observed in an unstable state. The strict relationship between this secondary flow and the rotor instability may be quite difficult to calcify analytically; however, it is shown experimentally that this secondary flow has a great influence on the instability of the rotor. Experiments are performed with rotors of various aspect ratios. As the aspect ratio becomes large, the self-excited vibration occurs at a lower rotating speed, and the range becomes narrower. A stabilization technique is also investigated. It is suggested that several rings be placed around the rotor to avoid this kind of instability.

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The bar is allowed only axial motion and compressed to a running plate with constant velocity by a spring. If the bar is inclined with an angle less than frictionai angle between normal of the plate, then the bar repeats a jumping motion. That the motives of this motion are like a deflection by a friction is confirmed by experiments. In this paper, the motives of the jumping motion of the bar are analytically examined, and the some conditions of generation of the motion are obtained.

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This paper describes the analysis of a dynamic vibration absorber with absolute damping which acts on the absorber mass alone. The analysis shows that the effectiveness of the dynamic absorber with absolute damping is greater than that of the conventional dynamic absorber. Two conditions of the main mass system are considered for the optimum tuning: the main mass system has undamping or damping. In the undamped system, the optimum tuning and damping of the dynamic absorber are formulated on the basis of the theory of fixed points. In the damped system, the optimum values of the dynamic absorber are obtained through the numerical analysis to minimize the two resonant amplitudes. The numerical results are given by the convenient empirical formulae. Also it is explained that the dynamic absorber has the effect of vibration prevention in the characteristic with a single resonance.

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In order to explain analytically the mechanism of non-linear damping force and limit cycle evolution, the present work derives an approximated differential equation of a single degree of freedom system with the closed-engine-governor loop, noting the phenomenon of very slow frequency while considering the results of the previous work. It gives a simple physical reasoning to the mechanism of the nonlinear negative damping force which causes an instability and a limit cycle evolution, resulting from a concept of the dynamic feedback-torque gain composing a nonlinear static feedback-torque gain and a virtual time-constant depending on the phase relations between the feedback torque and the engine speed. Results show that there is energy input during a cycle when the dynamic feedback-torque is larger than the inertia torque. This increases the amplitude, and at the final amplitude the energy put in by the negative damping force in the part the quantity of fuel injection is large is neutralized by the energy dissipated by the positive force in the part the quantity of fuel injection is small because of the nonlinearity of the torque characteristics.

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This paper is concerned with the system identification to calculate the characteristic matrices expressing the dynamic behaviors of structures by using the least squares method. The structure is excited by a random signal, and the measurements of the acceleration responses in a noisy environment are carried out. The accelerations, velocities and displacements of the structure are estimated from the measured noisy accelerations. The order of the structure is determined by evaluating the criterion of the identification. The effectiveness of the proposed approach is examined by the applications to a three-degree-of-freedom system as a numerical example, and to a cantilever beam as an experimental example.

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This study presents the fundamental characteristics for a flow-induced vibration of shell-type long-span gates which have a gate front consisting of vertical and inclined weir plates. The shell-type gates possess two freedoms to vibrate in the streamwise and vertical directions due to their bending flexibility. Both streamwise and vertical vibrations couple well with each other through hydrodynamical forces acting on the weir plates, thus resulting in a severe self-excited vibration. A two-dimensional model test for a shell-type long-span gate under small gate-openings was performed to measured the vibration frequency, the exciting ratio and the gate motion trajectories. From the obtained results, the fundamental characteristics, such as the vibration frequency ratios, a reduced fluid exciting coefficient, a reduced added mass, and a phase difference between the vertical and streamwise vibrations, were calculated. Furthermore, it was revealed from the measured gate motion trajectories that a press-shut device which causes a self-excited vibration is formed by a skillful dynamic mechanism of the coupled vibration.

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This study presents the calculated results for flow-induced vibration frequency and fluid damping of a streamwise vibrating vertical long-span gate under a small gate-opening. The gate vibration characteristics are determined by the following three non-dimensional factors: basic Froude number composed of the gate-opening depth and the vibration frequency in air, mass ratio of water to gate, and water depth ratio of the gate opening depth and the reservoir depth. The calculated results are shown in figures from which vibration frequency ratio and fluid damping ratio can be easily found for given non-dimensional factors. When the basic Froude number takes a value larger than 10.0, the vibration frequency ratio with an error less than 7% takes a constant value given by a simple expression of the mass ratio.

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Few detailed theoretical studies on hunting considering the nonlinearity of the creep force have been published to date. The Krylov-Bogoliubov method is applied to the analysis of the wheelset hunting having a nonlinear creep force between the wheel and the rail. As result, it became clear that a stable limit cycle exists, and its amplitude increases in proportion to the frictional coefficient-between the wheel and the rail. The amplitude of a limit cycle obtained by the approximate solution coincides well with the exact solution by the Runge-Kutter method. Furthermore, the amplitude of a limit cycle can be obtain immediately, because that of the limit cycle results in a formula of the van der Pole type. The results will be helpful for investigating the hunting phenomenon and designing wheel tread profiles.

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In this paper, two types of transfer coefficient methods, in which independent variables are only displacements, are applied to the calculation of the unbalance response of a rotating shaft. In one, the transfer coefficient is given in the form independent of rotating speed ω, and therefore this method is suitable for calculation at a large number of rotating speeds. In the other, formulation of transfer coefficient is easy and therefore this method can be applied to relatively complex totor systems, though the transfer coefficient is expressed in the form dependent on rotating speed ω. Even in the latter case, the computation can be done within 1/4 of the CPU time that is necessary for calculation by the conventional transfer matrix method.

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A method of calculating joint accelerations of a biped walking machine is proposed using Newton-Euler equations. The method transcribes all the phases in walking into the corresponding conditions on a linear equation with respect to the trunk, thus eliminating the conventional model change. The force and torque vectors from link i-1 to link i, the linear/angular acceleration vectors of link i-1, and the i-1 th joint acceleration are expressed recursively in linear terms with respect to the force and torque vectors from the ground to the foot (link 0) and the linear/angular acceleration vectors of the foot. The unknown vectors are solved by a 26×26 linear equation with respect to the trunk and feet conditions. Then the joint accelerations can be solved using the unknowns. Numerical experiment applied to a 4-degrees-of-freedom (dof) stilt machine solved the joint accelerations using this method. The condition number of the linear equation is 2×10⁴, thus double precision QR decomposition is employed.

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A method of magnetic levitation control of a traveling steel belt is presented. A traveling steel belt is supported in contactless manner by attractive forces of electromagnetic actuators which are controlled by feedback signals from gap sensors to stabilize the levitation behavior. A sub-optimal control theory is applied to minimize effects of spillover of residual vibration modes of the belt. To verify the usefulness of the method, an experiment of digital control was performed using a SUS430 steel belt.

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In order to improve the intelligence of a robot with a sense of touch, we have developed a tactile sensor array which can detect the distribution of the three components of a force vector. The tactile sensor consists of a 6×15 matrix of 3×3 mm sensing sites; each site is made of two single-crystal silicon rings on which semiconductor strain gauges are formed by means of a semiconductor processing technique. In this paper, we have introduced formulas to calculate applied force/moment, a center of distributed pressure, and some parameters of slip and hardness, and then carried out sensing tests in order to validate those formulas. Experimental results show that applied force/moment and the center of distributed pressure can be detected with practical accuracy. Slipping, rolling and rotating states can be distinguished by combinations of the slip parameters. Moreover, mechanical properties can be sensed by means of combinations of the hardness parameters. A lump in a soft object can be recognized using an adequate threshold method.

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This paper reports on the vibration control of a flexible space manipulator in which the tip deflection of each flexible link is fed back in a closed control system. A simple dynamic model is derived using the static deflection model to derive the system dynamics equations of a flexible manipulator. A force/torque sensor incorporated in the manipulator's wrist is proposed as a new type of sensors to estimate the deflection. To investigate the effectiveness of this control method, a two-link flexible SCARA manipulator system was constructed. This manipulator was 1.5 m long and was floating on a base-plate using air bearings capable of handling a 40kg payload. The experimental results showed that the deflection feedback realized the same effect on the vibration control as the general method of strain gauge output feedback.

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This paper discusses the potential use of an on-line computer aid for the trajectory monitoring of a robot manipulator. When the workspace is in full of unendurable state for worker, such as, for example, a nuclear power plant, a manipulator needs remote-control and an operator can watch its movement only from a fixed viewpoint like a small window. Accordingly, it is needed to monitor the movement of a manipulator from an arbitrary position. For Rhino robot which is training system for robot technicians, a method which monitors the figure and the trajectory of a manipulator, is proposed. Through an experiment, the effectiveness of the Rhino-aid monitoring system is evaluated. Furthermore, it is ascertained that this method isn't effective only for the operation of a manipulator, but also trajectory planning, since this system can check errors of a real trajectory from a desired one at anytime.

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Optimal control strategies are very useful in manipulation problems of robots. However, most optimal controls are highly sensitive to plant-parameter variations and disturbances because optimal controls try to pick up exact information from the mathematical models in order to realize the best performance. We recognize that difficulties are involved in exact modeling of plants and prevention of disturbances. Therefore, we need a optimal control method with low sensitivity. The ideas of closed-loop control system design using LQG/TR techniques (linear quadratic Gaussian control with transfer recovery) are discussed in this paper. We combine optimal controls and LQG/TR control into two-degrees-of-freedom control systems to reduce the sensitivities of optimal control strategies. In digital simulations, we obtained excellent results of a two-link manipulator in an optimal time control problem using our method. Some modeling errors and considerable disturbances are allowed in the method. Thus, we can realize good performances in practical manipulation problems using our method.

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A method for accomplishing high-speed compliant motion has been investigated. Several kinds of compliance control law has been proposed. One popular idea relates to adjusting the gain of the position servomechanisms constructed at each joint or at each axis of the compliance frame in robotic manipulators. When we adjust the gain in such a position servo sstem, the dynamic response will change because of the inherent dynamic effects in the system. For this reason, almost all systems proposed so far are effective only for low-speed motion in which inertia and nonlinear term effects are not serious. If we adjust the inertial, damping and nonlinear term effects, we may expect to be able to keep the dynamic response constant under various stiffness conditions. With this factor in mind, one control law has been formulated, and has been confirmed by experiment.

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The double pendulum type mobile robot which can shift from one horizontal bar to an adjacent bar has been studied. The robot is composed of pivoted double link arms with grippers installed on the free ends of the arms. The bars lie horizontally at regular intervals. Initially, the first arm of the robot grasps one of the bars with its gripper, and the second arm is hanging from the upper pivoted end. When the latter is swung by an actuator following the prescribed control path, vibratory excitation is induced on the whole system of the robot. Due to the excitation, the gripper end of the second arm is swung up through a large angle to approach to the neighboring bar. The gripper grasps that bar and the first arm's gripper releases the initial bar. Thus the robot moves laterally by one pitch of the bars, and it can shift continuously through the bar by repeating the sequence. Computer simulation and experiment were carried out on the robot by utilizing the control path and the optimal excitation condition derived from preparatory simulation. It is confirmed by experiment as well as by computer simulation that the robot can shift through the horizontal bar array by using the excitation of the system and the concept of the control path proposed here is very useful.

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A pressure attenuating system for a flow in a pipe whose compressor has a varying rotational speed was built. This system is composed of a Helmholtz resonator whose cavity's volume is automatically controlled by a personal computer such that the system retains the antiresonance. The steady state response and the transient response are investigated theoretically and experimentally by making use of the sinusoidal sound. When the exciting frequency shifts slowly, the sound pressure is reduced by 20 dB. When the tracking has a delay, it is possible that the system may pass through the resonance.

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Methods to predict a fairing's vibration level and interior sound pressure level were examined for the case in which the sound environment around the spacecraft is a progressive plane wave field. The following results were obtained: 1) The fairing's exterior sound pressure level can be predicted by using the analytical method for the infinite column of received progressive inclined plane wave. 2) The fairing's vibration level and the interior sound pressure level can be predicted with fairly good accuracy by the finite element method for the low-frequency range and by acoustic statistical energy analysis which considers the energy flow between exterior and interior acoustic field for the high-frequency range. In this case, the locality of the exterior acoustic pressure level should be considered.

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The effect of pivot bearings on the dynamic characteristics of the rotary actuator for head positioning in magnetic disk storage is experimentally investigated. The raiial spring constant and radial damping coefficient of single-row deep-groove ball bearings are obtained by experimental modal analysis. The damping coefficient decreases with increasing bearing axial prelode whereas the stiffness increased, and the damping characteristics strongly depend on bearing lubricating grease. Moreover, a resonance-antiresonance pair due to the pivot bearings appears in the mechanical transfer function of the actuator positioning system. The resonance is well suppressed by the damping effect of the lubricating grease. The results show that the effect of the pivot bearings on the actuator can be accurately predicted from the simple radial stiffness and damping of the bearing.

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An investigation was carried out to elucidate the natural vibrations of ball bearings. In this report, in-plane natural vibrations on the outer ring of a loaded ball bearing are studied. A point on the outer ring of the ball bearing under a thrust load was excited sinusoidally by a shaker. The radial responses of 35 points on the outer ring were measured by an accelerometer. Analyzing the radial responses, the modes of in-plane natural vibrations on the outer ring were obtained. From the experimental results, theoretical analysis and considerations, the existences of two types of in-plane natural vibrations on the outer ring of a loaded ball bearing were clarified, and frequency expressions for the in-plane natural vibrations on the outer ring were derived. Moreover, the remarkable accuracy of the frequency expressions was demonstrated.

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The method for the dynamic analysis of a rotor-journal bearing system in which large dynamic loads act on the rotor has been applied to an elastic flexible rotor system. In this analysis, the momentum equations of the rotor are transformed into ordinary differential equations by the finite element method. Journal bearings are approximated by the short bearing theory, and the bearing loads which act on the rotor are given by the Reynolds equations for oil films. The system is solved as a coupled problem of the momentum equations and the Reynolds equations for all the bearings. A rotor system for rotary compressors has been analyzed by the present method. The rotor action, bearing load characteristics and pressure distributions of oil films are thus determined.

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Recently, according to the enlargement of rotating equipment such as turbines and pumps, the dynamic characteristics of bearings and seals tends to greatly affect the dynamic characteristics of the rotor system. Therefore, numerous researchers have been engaging in developing the hydrodynamically lubricated bearing theory and seal theory. However, it is still difficult to estimate the precise dynamic characteristics of bearings and seals analytically. On the other hand, there are many researcher who have been developing the experimental measurement technique of bearing and seal dynamic characteristics. This paper describes the measurement technique of bearing and seal dynamic characteristics using the random excitation technique.

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The application of austempered ductile cast iron which showed load capacity comparable to SCM430 for making spur gears, to worm gears was attempted in addition to spur gears. However, with the worm gear, unlike the spur gear, considerable heat is generated along the tooth line because of large sliding. Acctrdingly, if hard material dose not harmonize with both worm and worm wheel, remarkable wear of seizing occurs. Consequently, in the present study, ductile cast irons with various hardnesses were prepared, and worm gears were subsequently prepared. In test operations with these worm gears, wear of tooth, temperature of tooth surface and transmission efficiency were investigated and compared with those of AlBC and S45C worm gears, which have been used formerly and the practical applicability was examined.

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For power transmission worm gears, the combination of phosphor bronze and hardened steel is commonly used. However, with the development of applications of synthetic lubricants, especially the advance of the lubrication technique, it has again been recognized as advantageous to substitute the phosphor bronze with a series of brass materials from the standpoint of saving resources, i. e., to reduce the component of copper. The pitting resistance, scoring durability, wear intensity, running-in and efficiency are regarded as the main aspects of performance being studied in wheel materials. The pitting resistances of wheels made from series of brass materials could obviously be determined from the simulation and real testing in the first report. In other words, although the marketed brass (BRB) has the same performance characteristics as described in the standard of JGMA, the improved high-tension brass (MBB) shows 3 times the loading capability of BRB, and it can be considered to be the same as the forged phosphor bronze. Since the performance against scoring was different from the fatigue strength studied in the previous report, this study was carried out.

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In order to elucidate the failure mode, the load carrying capacity and the relation between tooth profile change and dynamic performance in the fatigue process of carbonitrided steel gears, a carbonitrided chromium steel gear with a shallow hardened depth was fatigue-tested using a power circulating gear testing machine here. The failure modes of this carbonitrided gear were spalling on the tooth surface and tooth breakage due to spalling near the pitch point. The fatigue strength of this carbonitrided gear agreed almost with the lower limit of that of case-hardened gears and the upper limit of that of nitrided gears. The changes in the tooth profile and the dynamic characteristics during the fatigue process of this gear were slight.

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The authors introduced two kinds of new pressure-release ports for improving the performance of gear pumps with involute profiles. High-pressure gear pumps as well as low pressure ones were used for verifying the effectiveness of the new release ports. In the case of the low-pressure pumps, the total efficiency of the pump with the new release ports was higher by about 10% when compared with the one having conventional release ports. However, when the improved conventional release ports, which were found in a gear pump currently available on the market, were used, the increase reduced from 10% to about 4% at a delivery pressure of about 700 kPa. Running noise and vibration of the gear pumps with the new release ports were appreciably smaller than those of the one with the conventional release ports. In the case of the high-pressure gear pumps, the increase in the total efficiency was about 5% at a delivery pressure of about 10 MPa. The reason for the improvement in the total efficiency was clearly explained by the maximum pressure measured in the semienclosed tooth space between two mating gears of the gear pumps with different release ports.

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The previous report had shown that the vibration of gears can be estimated from the vibration of a pedestal with the transfer function. In this paper, the coherence function between the vibration of gears and a pedestal, which is obtained under operation, is examined. As a result, it is found that the frequency with high coherence, where the transfer function could be determined clearly, changes according with the rotating speed. Thus the pseudo-transfer function is defined as a collection of each transfer function having highest coherence at each frequency. Furthermore, various transfer functions by impact excitation in static state are compared with the proposed pseudo-transfer function for the possible way to obtain realistic transfer function, and optimal excitation method is discussed.

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First a design and production system of a new type of master gears of Hard Gear Finisher is developed. On this system, a pair of master gears can be designed and made more easily than the conventional master gears. Next the new master gears are designed and made for trial. Finally grinding tests are performed by using the new master gears on Hurth's Hard Gear Finisher. The works ground by using the new master gears have almost the same accuracy as the works ground by using the conventional master gears. Moreover, the new master gears have the ability to be able to modify the tooth surface of the work slightly. As a result, it is proved that the new master gears have a good performance.

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There are many measuring methods for W-N-type gears depending on one's situations, because we, in this field, have not yet established a measuring method for the work error of W-N-type gears. However, it can be determined by the measuring method for involute gears having such inspection items as tooth profiles, spacing and helixes, if one item for tooth profiles can be excluded. In this paper, the author showed some examples and problems in the measurement of W-N-type gears, actually measuring tooth profiles, spacing and helixes by using an involute gear measuring instrument and three-dimensional measuring machines.

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First, the position where the component of relative velocity on a plane is zero, secondly, the distribution of relative velocity centered by the zero point on a plane, and finally, the contact condition of skew gears on a plane based on the zero point and the relative velocity were investigated. From the results, the contact condition of skew gears by the medium of a plane such as spur gears is obtained. Also, the characteristics of the contact condition of skew gears similar to that of spur gears are obtained.

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Aiming to establish the estimation method of gear noises, the authors derived the basic theory for estimation of radiated sound power from the definition of the loss factor given by Ungar and Kerwin, without using the statistical energy analysis method. The theory was applied to the circular plates with a solid shaft as a simple model of gear bodies, and the vibration modes of the plates were analyzed under the assumption of mode damping. By using the result of the modal analysis, the equations for calculating the frequency spectrum of the three important parameters for estimation, the total loss factor, the driving point mobility and the radiation loss factor of the plates, were theoretically derived.

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The circular plates with a solid shaft were dealt with as a simple model of gear bodies, and the three parameters for estimation, the total loss factor, the radiation loss factor, and the driving point mobility of the plates, were calculated according to the theory and formulae derived theoretically in the first report. They were also measured. By using these calculated and measured parameters, the sound power radiated from the plates was estimated and was compared to the one measured by means of the sound intensity method. The estimated absolute frequency spectrum of the radiated sound power coincided well with the measured one. Then it was revealed that the estimation theory of radiated sound power was correct and useful.

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Improvement of the load-carrying characteristics of helical gears is one of the most important problems today. But the experimental results of these kinds of studies are comparatively scarce. For this purpose, we took up the subject of the frictional loss and the temperature rise of the teeth of the helical gears. Considering these situations, we studied the frictional loss of helical gears as a function of many factors, i.e., helix angle. sliding velocity of tooth surface, load, viscosity of lubricating oil and chemical construction of lubricating oil. The frictional loss grade of the helical gears decreases with increasing sliding velocity and viscosity of lubricating oil and increases with the helix angle and load. Further the frictional loss grade is very low when the synthetic oil is used. Finally, the relationship between the temperature rise of teeth and frictional loss was expressed with an empirical formula.

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To clarify the seizure resistance of the gears with the sulphurizing process, which is an anodic sulphurization performed in a molten salt bath with a temperature of about 190°C, four ball tests, two roller tests and gear tests were run under dry friction. Further, the correlation between the three test results on the seizure resistance and the frictional characteristics of the sulphurized layer was estimated. From the test results, it was found that the seizure resistances of the sulphurized balls, rollers and gears were about 2.5-3 times larger than those of un-sulphurized ones. The frictional characteristics of the sulphurated layer in the four ball tests were different from that in the two roller tests, and the variation in the bulk-temperature of the slower roller in the two roller tests was a little different from that of the wheel in the gear tests.

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It is important to investigate the tribological properties of corrosion-resistant materials in order to enhance the safety and reliability of offshore structures. In this study, the tribological properties of SUS304 stainless steel were examined in artificial seawater and compared with those obtained in air. The coefficient of friction was about one-half of that in air due to the lubricating effect of seawater. It was independent of normal load, but it increased with a decrease in oscillating frequency. Specific wear volume was lower than that in air by two orders of magnitude. The mild-severe wear transition against the normal load was not observed in seawater. Wear volume increased with a decrease in sliding velocity, which was contrary to the tendency obtained in air. This was caused by the significant electrochemical factor in the long testing duration.

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The pitching motions of magnetic heads sliding in contact with three different kinds of rigid disks were measured using an optical reflection system composed of a position sensor and a laser. It was found that a typical texture structure on a conventional aluminum disk motivated a free slider vibration at about 1.8 kHz with the amplitude of the pitching angle of the order of 2 μrad. A rectangular bump of 0.18 μm height induced a stumbling motion with the pitching angle change up to 0.2 mrad, which was similar in behavior to the case of a flying head but the magnitude was twice as much. Stick-slipping on a glass disk caused the head to slideasstanding on the front toe and keeping the pitching angle higher than 0.3 mrad. A simple elastic calculation indicated that over 10 μrad inclination of a slider would result in standing on the toe, and that its toe edge would depress the disk surface by an amount of about 2 nm. It was suggested that the depression by the toe edge would cause damage of the disk surface.

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In attempts to improve an automotive drive train efficiency, lower viscosity or multi-grade gear oil is used in automotive drive trains. At the previous paper, the authors proposed the method to measure the power loss in automotive drive trains which is based on the temperature rise of lubricant due to the friction in it. Applying this method to an automotive transmission, the power loss is measured with much higher accuracy and could be separated into losses caused by six elements i. e., input gear loss, output gear loss, lubricant churning loss, bearing loss, loss between gear and output shaft, and shift-fork loss.

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The centering operation which accurately sets a workpiece in a required position is important for precise manufacturing. However, this operation is usually conducted by the operator on the basis of his experience and has not yet been well automated. The relationship between an impact force applied on a workpiece and the dynamic displacement behavior of the workpiece is clarified in this paper as fundamental research for realizing automatic centering operations of workpieces. First, a frictional force model is constructed by considering nonlinear characteristics of the frictional force. Then, the dynamic frictional characteristics of workpieces on the contact surfaces are clarified using the numerical analyses of workpiece models with the frictional force model. The proposed frictional force model is proved to be appropriate for simulating the actual behaviors of workpieces by comparing the simulated results with the measured results with experimental equipment.

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The automated bonding technique for very fine insulated wires was required to keep pace with multipin semiconductors or high-density circuit boards. We obtained the relationship between the temperature and the time for thermal decomposition of the insulation of wires using Ozawa's method of analyzing thermogravimetric data, and found that it gives essentially the appropriate temperature. Applying this result, we developed bonding equipment for semiconductors.

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The mechanism of a continuously variable speed traction drive (CVT) with two internal spherical disks was introduced. Equations were derived for calculating changes in speed ratio and power losses caused by spinning motion at the contact surface. The effective traction force between the contact surface with an elliptical shape was calculated using the traction coefficient curves obtained by two roller tests and the resulting empirical equations. In this calculation, the effective pressure was introduced instead of a Hertzian mean pressure. The spinning loss was divided into torque and speed losses at the contact surface. Numerical calculation was made for these losses produced in a trial CVT with a capacity of about 5 kW at 1800 rpm. The equations developed may be applicable to any other type of CVT when some modification is made.

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Since laser cutting uses highly concentrated energy, it adapts more easily to the demands for higher accuracy, efficiency and quality than other thermal cutting methods. In recent years, the production of laser processing machines has increased rapidly, intensifying the demands for cutting quality. The source of heat in laser cutting is characterized by the beam-collecting characteristics, which greatly influence the quality of cutting and complicate the processing phenomenon. Therefore, it contributes to the expansion of fields applications for laser cutting and to higher manufacturing quality, clarifying the relation between the beam collecting characteristics and cutting quality. So we discussed and examined the factors of higher quality in the CO₂ laser cutting of Al alloy, non-oxygen cutting of stainless steel, and both thin and thick mild steel plates.

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For computer-aided geometric design or for computer-aided geometric representation, parametric curve segments and parametric surface patches such as the Bezier form or B-spline form have been frequently used. It is very convenient if we can use the same parametric representations for the approximation of algebraic curves or surfaces, such as circles, ellipses, spheres and tori. Then we can perform unified treatment for all free-form and nonfree-form curves and surfaces. For the design, machining and inspection of accurate geometry such as precision machine parts, it is very important to know the qualitative and quantitative error of approximation from exact geometry. But up to the present, little work has been done on this error. In this report, we treated the error of approximation and examined analytically and numerically the positions of control points and the magnitudes of the errors to approximate optimally algebraic curves and surfaces by cubic Bezier curves and by bicubic Bezier surfaces.

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Workpieces with an inclined end surface were drilled by a gun drill and a long drill. The inclination angles are 0°, 15°, 30° and 45°. The tool diameter is 18 mm. Besides this, another investigation with a parallel hole next to a probored hole was made. The wall thickness between the two holes, and the diameter of the prebored hole and that of the parallel hole were varied. As a result, the following points were clarified. The direction of the cutting force during the cutting of an inclined end surface influences the hole deviation. In the case of the gun drill, the hole deviates in the direction of the inclination of the end surface because the hole diameter becomes smaller than that of the tool, while in the case of the long drill, the hole deviates in the opposite direction of the inclination because the hole diameter becomes larger than that of the tool. Parallel hole deviation increases with the increase of prebored hole diameter. Hole deviation increases suddenly when the wall thickness between two holes decreases below a certain value.

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Among surface imperfections obtained by grinding, periodical marks caused by grinding vibration appear frequently. According to the mechanism by which the marks are formed, there are various kinds of features which can be important clues to diagnosing the type of grinding vibration and making appropriate counterplans. By classifing the marks due to each type of grinding vibration experimentally as well as theoretically, they can be divied into two major types depending on whether the marks are formed chiefly by a shape error or by a roughness variation. In addition, the relationship between the presence of the marks and the speed ratio, and the marks' inclination to the wheel axis are generalized to correspond with the different grinding processes and types of grinding vibration. The generalized relationship makes it possible to narrow down the possible causes to few types of vibration. Also, an optical method which is necessary for the diagnosis is proposed for measuring the features of the marks. Together with the principal counterplans for each type of grinding vibration, basic knowledge of vibration diagnosis has been obtained.

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An orthogonal cutting test was conducted using a high-precision machine to study the characteristic phenomena in micromachining of aluminum single crystals. The results of the experiments and the analyses can be summarized briefly as follows; (1) A high-precison machine having a microdepth cutting apparatus was produced by way of trial. (2) The size effect appeared in the cutting force # (F_h) when the depth of cut reached 1.0 μm. (3) The alternated phenomenon appeared in the cutting force # (F_h) and the chip length when the depth of cut reached above 1.5 μm. (4) The alternated phenomena can reasonably be explained through the introduction of the cold-worked region model. (5) The roughness and flatness of the finished surface were affected by the cutting direction, and this information suggests that control of the specimen orientation is effective for improving the working accuracy.

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The rigidity and deformation characteristics of an adhesive lap joint subjected to a lateral bending load have been examined both theoretically and experimentally. The deformations were analyzed using the theory of a beam on an elastic foundation. They coincided well with the experimental results. The deformations and rigidity of adhesive joints can be well estimated using the beam theory. Effects of the length of the bonded part and the thickness of the adhesive layer on the rigidity were clarified and a design criterion of adhesive joints was proposed. Furthermore, experiments with respect to the rigidity of a bolted joint were carried out and the results were compared with those of the adhesive joint. It was observed that, the rigidity of the adhesive joint was greater than that of the bolted joint when the thickness of the adhesive layer was thin, and that greater load could be applied to the adhesive joint than to the bolted joint.

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For a given power series y=Σa_nxⁿ, a root x may be determined as a series form x=Σc_nyⁿ and the operation is referred to as the reversion of power series. This means that it is possible to obtain an explicit solution to a transcendental equation which appears frequently in engingering mathematics. Coefficient formulae c_n=c_n(a₁, ···, a_n) up to n=6 are known at present and those for n>6 are desirable. Formula construction, however, becomes more complicated as order n increases and computer processing (numerical only) is preferable. This paper summarizes the theory and the algorithms of the reversion of power series as well as associated procedures. Also coefficient formulae up to the 15th order are listed. As an example, an explicit solution is obtained for the transcendental equation, cosXcoshX+1=0, the frequency equation of the flexural free vibration of a uniform bar with fixed-free boundary conditions.

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