This paper describes an analytical study on the effects of airspring deflation on the running vibration of railway vehicles. The vertical vibration characteristics, containing car body bending modes, are investigated for the situation excited by running on the track with vertical irregularities. The vibrations caused by the track irregularity of practical amount are evaluated with the value of the riding quality level, L_T, calculated from the car body acceleration, and they are compared between the conditions that the airsprings are normal or deflated. The running speed is broadly varied in the evaluation and suitable running speed is examined for the train operation under deflated airsprings.

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In order to improve the performance of the shock isolation-type concrete breaker, this paper deals with the theoretical analysis and ist design. The shock isolation-type concrete breaker was recently developed to reduce the detrimental vibration or shock caused in portable crushing tools such as the concrete breaker. However, its performance was not as good as expected, since the theoretical approach was lacking in the design stage owing to a very complex mechanism. So, a new method for analyzing the concrete breaker which combines the signal-flow graph and the digital simulation technique in introduced. Based on the results of this analysis, a modified shock isolation-type concrete breaker is demonstrated and the crushing energy is increased to 130%, regardless of reduction of the vibration of the main body to 115 dB in VL value.

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The engine-clutch-gearbox train of an automobile is modeled by a forced torsional vibration system including two nonlinear terms, namely a clearance (backlash of meshing gears) and a two-step-hardening spring (torsional stiffness of a clutch disk). Analytical solutions of the equations of motion of the system are obtained in recurrent form. Based on the solutions, the effect of the torsional stiffness of the clutch disk on the idle rattle of the gearbox is investigated. The results are as follows : (1) Sum of torque impulses per cycle of the forced motion increases with the increase in the ratio of the second-step stiffness to the first-step stiffness. Therefore, there is an upper limit to the second-step stiffness for the purpose of the prevention of the idle rattle. (2) Both the sum of torque impulses and the number of collisions per cycle of the forced motion decrease with the increase in the range of torsional displacement covered by the first-step stiffness. Hence, to prevent the idle rattle, the first-step stiffness should cover as wide a range as posible.

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The displacement functions of an axisymmetric shell with eccentrically attached masses are expanded using the free vibration modes of the axisymmetric shells without attached masses. These base vectors for expansion are calculated using a conical shell finite element. The expanded functions are used to express the strain energy and kinetic energy. The contribution of the rocking motion of the attached masses to the kinetic energy is considered. Also the effects of contained liquid are included. The strain energy and kinetic energy are substituted into Lagrange's equations to obtain natural frequencies, vibration modes and response for base excitation. Analytical results using the present method show good agreement with analytical results obtained by other methods or experimental results.

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An investigation was carried out to elucidate the natural vibrations of ball bearings. In this report, the vibrations of fifteen ordinary-size ball bearings were studied. The ball bearings were operated at a constant speed under a thrust load. The radial, the axial, and the resultant vibrations on the outer ring of each ball bearing were picked up by a stereo cartridge. The vibrations were analyzed by a fast Fourier transform analyzer. Moreover, for the natural vibrations on the rigid-body mode of the outer ring, modal analysis was carried out. From the experimental results, analysis and considerations, the vibration characteristics of ordinary-size ball bearings were clarified, and frequency expressions for the natural vibrations on the rigid-body mode of the outer ring were derived.

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This paper describes the active vibration control in the case of steady-state unbalance responses in flexible rotor systems. The control system consists of state feedback to stabilize a system and feedforward control to completely cancel unbalance forces at the designed rotational speed. This is called an output regulation theory with internal stability. At first, unbalance forces are regarded as state variables. Next, a state observer is designed in order to estimate unbalance forces because they cannot be directly measured. Feedforward control forces are produced by an opposite sign of the estimated values based on an observer. This theory has been applied to two kinds of flexible rotor systems, a single degree and two degrees of freedom systems. The amplitudes with control have been experimentally reduced to three percent near the first critical speed and twenty percent near the second critical speed.

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This paper is concerned with controllability and observability for a flexible rotor system supported by active magnetic bearings. The criterion of two steps concerning controllablity and observability is proposed based on the concept that a control system of magnetic bearings consists of position feedback and velocity feedback in general. The first step of the criterion is for a position feedback and the second step is for velocity feedback. The first step is to check free-free modes for only flexible rotors. In the second step, flexible modes including position feedback loops have to be analyzed because free-free modes are varied by position feedback gains. We can explain and make clear the experimental vibration behaviors which are very stable until just before the fourth critical speed, become unstable in passing through the fourth critical speed and then become stable again.

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A new criteria to estimate an absolute unstable vibration of a tube array caused by liquid gas two-phase cross flow has been proposed here. This new criteria, which fits for the flow pattern from slug flow to froth flow, is based on the new method to calculate the flow speeds, the intermittantly rising velocity of the liquid slug, and that of the gas flow. The analytical results have been compared with the experimental data and the existense of the intermittant unstable vibration has been checked.

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The electromagnetic bearing has high potential of supporting a high-speed rotating shaft. One of the most serious problems is the cross-coupling effect caused by gyroscopic or Fleming force. This paper treats the gyroscopic effect which moves the duplicated resonant poles: one to high and the other to low frequency. Usually the controller has an unstable frequency range caused by integral control or higher delay. The backward precessional motion is apt to be unstabilized by the integral control. A rotationally interrupted cross-coupling control is introduced to compensate for the undesirable precessional motion. This scheme is applied to an active magnetic bearing system, and its capability is tested.

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This paper describes a new algorithm for dynamic analysis of mechanisms. Motion of a kinematic pair is modeled as that of a compliant mechanism supported by springs except its originally possible motion. The force and moment acting on each link are determined as functions of a deviation between two elements of each kinematic pair, and the motion of a link can be computed using the Runge-Kutta method. By this algorithm, it becoms possible to compute dynamic characteristics of a mechanism such as displacements, velocities, accelerations, etc., at the same time.

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For the attitude and vibration control of a flexible structure, such as a spacecraft having flexible appendages, it is important to know design parameters such as the moment of inertia and the location of the center of gravity. But, generally, it is very difficult to calculate these design parameters in the case of a structure whose configuration is very complex. Thus, it is necessary to develop a technique to determine these parameters from vibration test data. The test data of a flexible structure such as natural frequencies, modal damping ratios, and mode shapes are different from those of a structure regarded as a rigid body, because of the interaction between a rigid body motion and flexible appendage motions. Therefore, this paper proposes a method of direct identification of these parameters from vibration test data measured in the state in which a flexible structure is supported by elastic mounts. The method is based on the motion equation taking into account elastic deformation of flexible appendages. The usefulness of the proposed method is illustrated by carrying out identification of a calculation model and an actual simple structure composed of a rigid body and two flexible appendages.

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This paper deals with an experimental modal analysis method for large-scale structures such as boiler plants in thermal power stations. Practical and accurate modal identification has been carried out by the proposed method, which is composed of two stages : (1) processing transfer functions by autoregressive (AR) spectral analysis, and (2) a curve-fitting technique to extract modal parameters. Seismic records of base acceleration are utilized as input data, and a series of response acceleration records at various points of the structure are utilized as multi-output data. This method is examined using time-series data of seismic response simulation. Introduction of two techniques, namely, decimation of time data and FPE criterion to optimize the order of the AR model, have realized effective and accurate identification. This method has actually been applied to in-situ seismic observation data of a boiler plant in operation. As a result of these investigations, this kind of modal identification has proven to be an effective tool for seismic modeling of large-scale structures.

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A polyhedron shell such as a box-type structure is used to cover a noise source and muffle emission noise. However, this structurre vibrates easily and cannot muffle noise completely, since it has low damping qualities. This paper shows that a number of resonance peaks occurring in a polyhedron shell can be suppressed by using a design method of dynamic absorbers to control the vibration of multi-degree-of-freedom systems, and this method will possibly be used to control this type of noise in the future. Four dual dynamic absorbers designed by the experimental method could control the vibration of the structure well. The effectiveness and generality of this method is confirmed by the modal analysis using the finite element method.

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Flexibility in the joint driving system produces vibratory behavior in the motion of a robot arm. This decreases the quality and efficiency of tasks executed by a robot arm. This paper examines three kinds of vibration control method using joint torque feedback from the viewpoint of the closed loop eigenvalues and time responses. The angle of departure of the eigenvalue-loci with respect to torque feedback is also discussed. It is shown from control experiments and theoretical analysis that the simple control method proposed in this paper gives satisfactory results.

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The new rolling stock test stand at Railway Technical Research Institute has a vibration system of the rollers in the lateral direction and in the vertical direction. Using this test stand, dynamic behavior of a bogie was tested. The test stand has so far been used mainly for examination of hunting stability. However, using the experimental results of the bogie test, it is also possible to estimate the suspension stiffness and damping characteristics of the bogie. This paper deals with the method and results of this estimation. If the railway vehicle running on rail is simulated using the model and estimated value, it is expected that more accurate results on vehicle dynamics will be obtained.

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To prevent the hunting and to raise the running stability of railway vehicles, it is extremely important to make clear the geometrical contact between the wheel and the rail. In this paper, the contact geometry between the rail and the wheel tread profile consisting of one circular arc forms, is analyzed theoretically in detail, and the exact solutions are compared with the approximate formulas. The theoretical analysis has made clear the following points. There is an inclined angle between the horizontal line and the center line of the wheelset due to the lateral displacement of the wheelset. There are also a variation of the radius of the wheel at the contact point between the wheel and the rail, a vertical displacement at the center of gravity of the wheelset, an effective conicity at the contact point, a variation of the radius of the wheel originating in the radius of the wheel of a roller rig such as the test stand of a vehicle, and a variation of slope at the contact point due to the angular displacement of the wheelset, and so on.

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For the purpose of increasing the running speed and ensuring the running performance and safety of a high-speed vehicle, it is necessary to improve the prevention of hunting, improve the running performance in passage of curves and suppress erratic vibration due to track irregularities. In the present paper, the steering, Z-link suspension device mechanism, truck on the new conception for the high running stability on both straight and curved sections of the track is presented, and the hunting characteristic is examined in comparison with that of the SHINKANSEN vehicle. From the theoretical calculation, it becomes clear that the new truck has a slight toward expansion of the unstable region of body hunting in comparison with the SHINKANSEN truck. However, supplementing/both the adequate supporting stiffness of the axle and the elastic moment against the truck turning is an effective method of preventing body hunting. Furthermore, increasing the angular displacement of the rear axle to more than that of the front axle has the remarkable effect of raising the critical velocity of the truck hunting.

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Rail vehicles must have both good curving performance and stability at high speeds; such vehicles have a compound circular wheel profile, soft suspension of the wheelset and a yaw damper. A detailed dynamic model (31 DOF) for these vehicles was formulated, and general equations of motion were derived considering various nonlinearities such as wheel profile, clearance in wheelset suspension and creep force between the wheel and rail. Digital simulations for a representative example were made. It was shown that the yaw damper had a large effect on improving stability, especially suppressing divergent hunting at higher vehicle speeds. Then, eigenvalue analyses for the linearized model were made and the cause of the above-mentioned effect of the yaw damper was clarified. The influences of some other factors such as clearance in the wheelset suspension and stiffness of the springs inserted in the ends of the yaw damper and lateral damper were also described.

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Railway passenger car bodies have been parametrically designed based on empirical knowledge of expert designers. To meet demands for systematic and satisfactory design, this paper presents a new computer aided design method to determine satisfactory structures and dimensions using sensitivity analysis and empirical knowledge. Data of a tentatively designed structure is inputted into a computer using a product modeling technique. The structure produces an evaluation model consisting of sections called blocks which in turn consist of components. Introducing sensitivity analysis we can evaluate the effectiveness of the weak parts of all blocks and all parameters of the components. Responding to the analysis in terms of empirical knowledge, the priority list of parameters to be modified is decided, since designers expect the new method to be as usable as conventional methods. On a railway passenger car we obtained a practical solution in less than 28 hours, after examining all possible cases of the modification.

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The optimal operational planning model is extended to the cogeneration system including the Cheng cycle gas turbine power generation unit, which has high flexibility to change the ratio between the heat and power outputs. By adopting the mixed-integer linear programing method, it is ascertained that the operational policy of the total system can be determined intelligently. Through a case study on a district heating and cooling system, the economical aspects of the Cheng cycle cogeneration system are compared with those of the gas turbine-waste heat boiler cogeneration or the conventional energy supply systems, and the advantage of the former system is recognized as compared with the latter systems.

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The radiation of sound from a mass-loaded, baffled beam has been studied. It is assumed that the beam is carrying a concentrated mass at its middle and is simply supported at both ends. Closed-form approximate expressions are developed for the radiation efficiency of a mass-loaded beam for a region below the coincidence frequency. It is shown that an extreme change of the radiation efficiency occurs due to attaching of a mass to the beam. The value of the change, does not depend on the mode number of the beam vibration but depends on the ratio of the acoustic wavenumber to the beam length, the phase relation between the response of the mass and that of near boundary, and the response of the mass. The assumption of a complete wave cancellation, except at the two ends and the mass point, is valid and useful in estimating, the radiation efficiency of a mass-loaded beam for a region well below the coincidence frequency region.

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The data bases of DC Servo motors and reduction gears on the market are constructed. Based on them, the minimum capacity method is proposed as an exellent selection method of motors and reduction gears, which makes the capacities of motors minimum for given mechanisms and works. Motors and reduction gears are selected for some robot mechanisms and prescribed works by the minimum capacity method and by the impedance matching method respectively, and the amounts of energy consumption by the motors selected by the two methods are calculated and compared with each other. Contributions of the self-locking function and efficiency of reduction gears to the energy consumption are also discussed.

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To eastablish a fundamental concept for the precision design of a gas bearing, static and dynamic run-out characteristics of a rotor supported by an externally pressurized gas-lubricated thrust-collar bearing are investigated in this paper. The concept is based on the theoretical results developed in the previous papers on load capacity fluctuation, which is caused by machining errors such as the out-of-perpendicularity of the rotor-end surface and the size deviation of supply holes of the bearing, as well as on the fundamental bearing characteristics such as stiffness and damping coefficient. The "averaging effect" for the rotor run-out characteristics is evaluated quantitatively. The experimental results for the amplitude of the rotor vibration coincide well with the theoretical results, which may confirm the validity of the theoretical model used in this study.

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A new type of grooved bearing whose axial load carrying capacity is improved is proposed in this paper. The present type of bearing is composed of herringbone journal bearings, a spiral grooved bearing and a path hole which connects the middle of each bearing. A lubricated gas flows through a hole path by the pumping effect of herringbone grooves. A generalized method of numerical calculation using the narrow groove theory is introduced in this paper for the analysis of the present type of grooved bearings. As a result, of the numerical calculation, axial floating characteristics of the present type of grooved bearings are superior to those of conventional bearings.

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The tooth surfaces of hypoid pinions are generated by the 3rd gear members which are composed of the cutters and their positions or tilting angles on the pinion generators. In such cases, it is useful in the gear factories to apply the cutting pitch cones instead of the pitch cones to the tooth bearing development of hypoid gears. This paper presents relationships between the cutting pitch angles and the tooth bearing patterns introducing the small increment effects of the pinion offset.

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A hypothesis is assumed in that the empirical estimation reached by mechanical engineers in designing, trouble shooting and so on is worked out not by "rules" stored in the knowledge base which is deduced from their experiences, but by simple inter-or extrapolation of data concerning the objective matter in the memory of their experience, which are not conceptualized in the form of "rules". In this report a model for this is proposed. The procedure of prediction according to this model is as follows : 1. Specification of factors which influence the objective matter, and classification of concepts of nonnumeric factors among them in a tree structure. 2. Construction of the data base according to this conception structure. 3. Investigation of the degree of resemblance in objective matter between the investigating example and each example in the data base. 4. Decision of the estimating value by enveloping extrapolation of distributing points on the "objective matter vs degree of resemblance" chart. Predictions of gear vibration according to this model have proved that the accuracy of the estimation is quite good. When this model is incorporated in an expert system, it is no longer necessary for knowledge engineers to form "rules" by consulting experts. The job of knowledge engineers is to construct the attributes of the data base, that is, to construct the tree structure of the conception of factors which influence the objective matter.

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Design of nonintersectingm-nonparallel-axis conical involute gears is established. As a result, any conical involute gears which transmit a rotational motion between two nonintersecting-nonparallel shafts can be readily designed and made. This design is composed of two methods. One is a method to determine mounting dimensions when the basic dimensions of a pair of gears are given first. The other is a method to determine the basic dimensions of a pair of gears in the case when the mounting dimensions are given first. The test gears are designed and made for trial, tooth bearing tests are performed, and it is proved that this design has applicability.

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An experimental study has been made of the effect of temperature rise on rheololgical properties of some mineral and synthetic hydrocarbon base oils over a wide range of temperature. The representative stress τ₀ expressing the limit of Newtonian is determined by a curve fitting method from a traction curve obtained on a four-roller machine while the effective viscosity-pressure coefficient α^- is derived through the experiments using a high pressure viscometer. When the temperature is raised, α^- falls and τ₀ rises. The behaviour of τ₀ for paraffinic mineral oil and α-olefine oligomer follows the Eyring theory while the effect of the dissociation of molecular clusters appears with naphthenic oils. The increase in temperature causes a reduction in the maximum traction coefficient, which can be predicted by the theory using the rheological parameters expressed as a function of temperature with the error of 10 % at most.

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In order to obtain fundamental data about tooth surface durability and the tooth surface failure mode of induction-hardened sintered powder metal gears, rollers made of two kinds of powders with diameters of 30 and 60 mm were fatigue-tested with pairs of the same diameter rollers under a sliding-rolling contact condition. The surface failure mode in this experiment was spalling due to subsurface cracking. The depth of the spalling crack agreed with the depth of the maximum amplitude of the ratio of orthogonal shear stress to Vickers hardness. The surface durabilities of the rollers increased as the relative radius of curvature decreased, and they were hardly influenced by the powder type and the sign of specific sliding.

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Periodical variation of the light reflectivity is known to be generated on a ground cylindrical surface due to the onset of the so-called wheel regenerative vibration that increases in magnitude with the progressive wear of the grinding wheel accompanied by the formation of waviness. Multiple asperities of the waviness indicates the higher harmonic components of the fundamental vibration due to the relative runout of the wheel surface. To understand the nonlinear mechanism that causes the higher harmonic and the vibration frequency behavior, grinding experiments and theoretical analysis have been performed. It is known that when the relative wheel runout is greater than or nearly equal to the rate of removal, the nonlinear variation of the equivalent chip load occurs through the geometrical interference between wheel and workpiece, and it is responsible for the origin of the higher harmonics in the dynamic grinding force variation. Also, the sensitivity of the frequency of the wheel regenerative vibration depends on the modal flexibility of the structure measured relatively between the wheel and the workpiece.

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A highly hardened steel (SK 5) was ground with CBN or WA abrasive grains, and some features of ground surfaces (structure, hardness, residual stress, etc.) were studied. It was found that spark-out raised compressive residual stress near the ground surfaces in every case, especially when CBN abrasive grains were used. This suggests the effectiveness of spark-out in raising fatigue strength. It was also found that grinding with CBN abrasive grains raised the hardness, in contrast to the lowering of the hardness after the grinding with WA abrasive grains. This suggests a rise in the wear resistance due to the grinding with CBN abrasive grains, contrary to the case of grinding with WA abrasive grains. The above-mentioned difference caused by the difference of the abrasive grains may be attributed to the difference in the heat conductivity, etc., of the abrasive grains, which caused the difference in the structure of the ground surfaces.

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The quenched and tempered carbon tool steel (SK 5, about 750 Hv) was polished with a silicon carbide abrasive paper or a diamond abrasive cloth, in a wet condition. Observations revealed that most of the cracks originated at slip bands in surfaces polished with silicon carbide abrasive paper, after a fatigue test, whereas in the surfaces polished with diamond abrasive cloth, fatigue cracks originated from inclusions. Besides this fact, several differences between the surfaces polished with silicon carbide abrasive paper and those polished with diamond abrasive cloth were perceived from other observations and measurements. The above-mentioned facts suggest the necessity of taking the kind of abrasive grain and adhesion to paper or cloth into consideration in preparing standard specimens for fatigue tests which are frequently finished by polishing. In addition, it is required to state what abrasive grain and adhesive were used when presenting fatigue test results.

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Roll-finishing of a gear with the surface hardness of H_RC=55 was very difficult because of the interference between the tooth tip of the die-wheel and the tooth root of the work-gear. The main purpose of the present report is to roll-finish such a quenched gear. For this purpose, experiments of roll-finishing were carried out using a crowned die-wheel which enables low load operations. Work-gears were cut by hob with a protuberance so as to prevent interference. As a result, it was found that a gradual feed of work-gear in its axial direction contributes to improvement of the tooth form accuracy of a gear with the high surface hardness. Furthermore, investigations of the tooth form of die-wheel after roll-finishing experiments reveal that the distributed loads on the tooth flank of the die-wheel do not exceed the load capacity of die-wheel material, but the tool life of the die-wheel may be shorter than that in roll-finishing of unquenced gears.

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In the honing operation, the influence of the honing head design on the out of roundness of a workpiece is investigated theoretically. Harmonic analysis is applied to fit the curve to the shape of the cross section of the workpiece. Using the three-stick honing head, the amplitude of waves of degree 3, 6, 9, ··· is attenuated more rapidly than that of waves of degree 2, 4, 5, 7, ··· as the honing proceeds. The four-stick honing head can not attenuate the amplitude of waves of degree 3, 5, 7, 9, ··· but attenuates that of waves of degree 2, 4, 6, ···. In the case of the honing head with greater sticking, the amplitude of some waves is amplified. The influence of the space of stick and shoes around the periphery of single-stick honing head on the out of roundness is investigated.

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Using the honing machine, the influence of the honing head design on the out of roundness of workpiece is investigated experimentally. Experimental results for three and four-stick honing heads agree well with the theoretical results obtained in the 1st peport. In the case of the honing head with greater sticking, the simulation of honing operation is carried out using the micro computer and the results obtained are compared with the theoretical results.

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A layout design of a system such as a power plant is a time-consuming and expertise-based task and needs to satisfy the spatial constraints among the elements composed of a design object. In this paper we propose a new general approach with two concepts; the constraint-directed reasoning based on the domain concept to operate the preliminary stage of layout design, and the generate and test procedure to deal with various kinds of layout specifications. From the above concepts, the layout specifications are generalized and classified into the four groups of constraints. The domain means here candidates for layout of a element, and the layout procedure is executed in the process of the generation, test and selection of the candidates considering each group of constraints. Moreover, we propose the concept of layout potential in order to reflect the global layout situation for the optimum of the layout result and the smooth layout operation. The proposed approach is composed of the general procedures and the individual specifications which can be represented with declarative form, and have the generality and the applicability to various kinds of layout design.

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A layout design of a system such as a power plant is a time-consuming and expertise-based task and needs to satisfy the spatial constraints. In the first report, we have proposed the general approach composed of the general procedures and the individual specifications on a layout. In this paper, we construct the system based on the proposed approach with object-oriented programming technique. On the system, the general procedures such as constraint propagation are represented as methods on the class objects with the hierarchical structure for the representation of the specifications, and the individual specifications of a design object such as a layout space, components and spatial constraints are represented as instance objects and associations among them. Moreover, we provide the useful interface for interaction with a user and the representation of a layout result. The system structure has the generality and enables to apply it to various kinds of layout design.

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Two different algorithms are applicable in computing a lower bound value of the objective function for a dynamic lot production planning problem with multi-items and multiple resources. These are the linear approximation method and the Lagrangean relaxation method. This paper first presents the fact that the lower bound values obtained by these algorithms are theoretically identical, if the Lagrange multiplier of the Lagrangean relaxation method is properly adjusted. Then comparison of computational efficiencies and comparison of computational accuracies concerning the lower bound values are made through many numerical experiments using the fractional factional designs.

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The problem of deciding whether two objects are of the same shape, i. e., similar or not, is very important in the classification of shapes of objects for robot vision and in the creation of knowledge-based systems. A new algorithm for this problem, which is based on the idea of decomposing a polyhedron into convex polyhedra and connecting them with the hierarchical tree structure, is presented. The algorithm consists of the following two procedures : 1) Whether two hierarchical tree structures for two polyhedra equal each other or not is tested. 2) Whether two convex polyhedra belonging to each node equal each other or not is decided. The number of operations is proportional to the number of vertices, if the vertices are uniformly distributed in 3-D space. Otherwise, the running time becomes proportional to n log n, where n is the number of vertices of a polyhedron. The program is written in FORTRAN language and the running times for the various polyhedra are measured. The results guarantee the theoretical considerations.

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