The offensive electromagnetic noise generates when natural frequencies of a stator core with windings and frame coincide with or are close to frequencies of the magnetomotive forces. So, in order to avoid such noise it is necessary to estimate natural frequencies of the stator core in the design stage. Therefore, we have studied and found a practical method to obtain natural frequencies by using the finite element method (FEM). In this case the most important and unknown constants are Young's moduli of windings which are composed the enameled wires, insulation films and vanish. From experimental investigations the reliable and practical Young's moduli were obtained. We call these moduli as the equivalent Young's modulus for FEM analysis.

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This paper deals with the uniqueness of identified mass and stiffness matrices in system identification. Using the constrained minimization theory, these matrices are so identified as to minimize the Euclidean norm of the matrices. Current identification methods with constraints on the modal masses can never give a unique mass matrix because mode shapes are relative ratio of amplitude at points on structures. This paper proposes that the measured mass properties of a structure and mode orthogonality are introduced into the constraints to solve this problem. The proposed method is applied to a cantilever beam. Numerical results show that the proposed method gives unique mass and stiffness matrices.

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Presented here is a novel electrostatic separating method of plastic mixtures. Separation takes place in a vibratory feeder equipped with an electric field separator. By using the method, we studied the separation of polyethylene (PE) from polyvinylchloride (PVC) particles after tribocharging. Tribocharging of the particles took place in a mixer with an impeller. The influence of electric field strength and amplitude of conveying surface on the separation efficiency was investigated. The purity of PE was 99.3±0.1% at the recovery of 86.5±1.0%. The purity of PVC was 97.6±0.2% at the recovery of 91.1±1.7%.

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In a system driven by a pneumatic actuator, friction at the seals between parts is one of the nonlinear elements that has an undesirable influence on the system's stable motion and control accuracy. In particular, when the system works at extremely low speed, the friction causes oscillation, and frequently this evolves into oscillation with sticking phases; i.e., stick-slip. The objective of this paper is to analytically derive the occurrence conditions of stick-slip. In the process of derivation, we analyze system stability under some assumptions and specify the main factor affecting oscillatory behavior. In addition, we investigate the behavior of solution trajectories on a phase plane with numerical simulation by choosing an effective sectional area of restrictors as a parameter then varying it. Based on the cases that the trajectories reach a negative region, the occurrence conditions with respect to pressure are finally found. Their validity is confirmed by applying them to experimental results.

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The averaging method improved by using the Jacobian elliptic function is developed in order to obtain a highly accurate periodic solution for a strongly nonlinear system. The Jacobian elliptic cosine function (so-called cn function) is used as a generating solution for the harmonically excited Duffing-type equation with hardening spring and damping. The stability for approximate solution obtained by the present method is also discussed. By comparing with the very accurate numerical solutions obtained by applying the shooting method, it is confirmed that the present method gives more accurate solution than that obtained by the traditional averaging method using the trigonometric function. In addition, not only the fundamental amplitude but also the higher harmonic amplitudes of the solution obtained by the present method are in good agreement with those obtained by the shooting method.

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Motion of a vibrating system attached to a vertical shaft with a small clearance is examined experimentally. When the shaft is still, the vibrating system climbs down as well-known. However, the vibrating system climbs up in the case that the shaft is vibrated sinusoidally with adequate amplitude and frequency. When the vibrating system climbs up, its motion is entrained to the shaft vibration and the frequency ratio of the vibrating system to the shaft is 1/1 or 1/2. Calculated results based on a simplified model with three degrees of freedom agree well with experimental results not only qualitatively but also quantitatively. The effects of amplitude and frequency of the shaft vibration and the mechanism of the climbing-up motion is also discussed.

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This paper deals with characteristics of the elliptic resonator. The resonator consists of loop and leg part, respectively. Each part was actuated by bimorph type piezoelectric member. The deflection of loop part and the bending of leg part generated by piezoelectric bimorphs makes an elliptic motion at the center point of the upper member. If resonators are put in a train and are actuated at the same frequency, it can feed objects on the upper surface of its train. There are two type of resonator, arch type and pentagonal type. Arch type resonator generates big amplitude on the center of upper surface. Bending its under member, pentagonal type resonator generates amplitude on the whole upper surface. Calculated results show that a shape of resonator influences on natural modes and natural frequencies. The trial one could generate elliptic motion in arbitrary phase with both type resonator. A pentagonal type resonator with notch reinforces its torsional stiffness and can generate necessary natural modes and an elliptic vibration without generating other natural modes.

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For the design support tool of multibody mechanical systems, many formulations and numerical calculation methods are proposed. For example, there are DAE methods using the Lagrange multiplier, ODE methods using coordinate partitioning technic, the penalty methods using the constraint error, etc. These methods can be applied to multi-degrees-of-freedom systems, and the generality is high. In the meantime, small mechanical systems possessing a few degree of freedom with holonomic constraints are not little. In such case, it is convenient that there is the formulation in which analysts can easily make computer programs, even if they do not use the expensive softwares of multibody dynamics. In this paper, I propose the new simulation method for multibody systems possessing 1 degree of freedom with holonomic constraints. It is easy to deduce the equation of motion for that systems by using the proposed method. Newton iteration method is used for the numerical calculation. The stabilization methods for holonomic constraint errors like Baumgarte method and penalty methods are not required, because kinematics, dynamics and numerical integrations are analyzed simultaneously. Finally, we show numerical examples to demonstrate effectiveness of this approach.

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This paper investigates disturbance cancellation control to suppress vortex-induced vibration of a circular cylinder in a cross flow. The controller consists of an optimal regulator and a feedforward control. The external force of the vortex shedding is assumed to be a harmonic force, and the magnitude of the disturbance is estimated by a minimal-order observer for the feedforward control. The cylinder is supported by two pairs of elastic beams, and electro-magnets are used as control devices. Experiments have shown that the present method is effective in reducing the vibration amplitude of circular cylinders. We investigate the effect of frequency error in the observer on disturbance cancellation control.

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This paper describes the way of applying an active magnetic levitation system to active vibration isolation system that controls a micro-vibration and the results of the evaluation experiments. The control system, based on H^∞ control theory, was designed to be used for an augmented system in each degree of freedom for the independence. A control system features a combination of H^∞ and PI control methods for control in the vertical system. The system was actually tested to ascertain its performance on non-contact levitation and micro-vibration control. It was confirmed that the H^∞ controller is capable of effective non-contact steady levitation, as well as micro-vibration isolation. The experimental results by a test apparatus showed that the designed controller yielded a 90% in vibration cancellation and effective external force suppression.

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This study aims at the realization of capsule transport of the little type using ultrasonic wave. The ultrasonic wave produces the force which pushes the object in the propagation direction of wave, when it is obstructed by the object. This is the acoustic radiation force, and the capsule is moved in a small pipe by this force. In the experiment, a small diameter pipe is installed in the horizontal and vertical direction, and then ultrasonic wave is radiated from the end of a pipe, and the capsule movement inside a pipe is observed. The experimental results are shown in this paper. Next, the result was reported the movement method of the capsule using ultrasonic wave is investigated.

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This paper concerns the minimization of total acoustic power radiated from a vibrating panel using both active noise and vibration control approaches. This paper begins by deriving the optimal feedforward control law for minimizing the total acoustic power radiated from a vibrating panel:three kinds of control strategies for minimizing the total acoustic power are presented in the work. It is found that acoustic control power at every secondary source location always becomes zero under the optimal control condition. It is also found that the vibration control power at each control location becomes zero under the optimal control condition. The fact that the control power for both acoustic and vibration stance becomes zero turns out to be a necessary condition for the optimalicy. Using the acoustic intensity distribution as well as the vibration intensity distribution, these phenomena are investigated. Finally, control effects for minimizing the total acoustic power for two casesuse of a single acoustic secondary source and a single vibration controller, and use of four acoustic secondary sources and a single vibration controller-are shown.

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When sheet steel travels at high speed in a processing facility, rollers are usually used as supporters. However, when rollers are used, deterioration caused by cracking is possible. The authors have proposed a magnetic levitation control system for sheet steel and confirmed the feasibility by an experiment on digital control. However, there is no horizontal restraining force in transport in the case of using only levitation control. Therefore, we proposed to install electromagnets in order to control the horizontal position. For the basic examinations, the rectangular sheet steel (length 800 mm, width 600 mm, thickness 0.3 mm) was reinforced by light carbon pipes in this study. To verify the usefulness of the proposed noncontact positioning control system of sheet steel, a digital control experiment was performed on transport. As a result, good positioning control performance for the levitated steel plate was obtained.

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This paper is devoted to study time optimal control problem for deployment of a gravity gradient stabilized space structure. Schematic model of the space structure is a rigid main body equipped with mass-less booms tipped with point masses. Numerical results for three initial pitch angles show that time-optimal deployment control to eliminate pitch motion is the bang-bang control that consists of five phases; (a) simultaneous extension toward yaw and roll axis, (b) extension toward yaw axis, (c) suspension of extension, (d) extension toward roll axis, and finally (e) simultaneous extension toward yaw and roll axis, again.

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The stability characteristics of two-lobe journal bearings with surface wear dents are studied theoretically. A wear dent is assumed to be on the lower pad surface, and the static and dynamic bearing performances are calculated. Then linear stability thresholds of a Jeffcott rotor in the bearings are obtained. The surface wear dent is found to affect the stability characteristics, depending on the preload factor and the wear depth.

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This paper describes experimental verification of the theoretical stability characteristics of twolobe journal bearings with surface wear dents. Vibration of an elastic rotor supported in a bearing with a model wear dent was measured and stability threshold speeds were obtained by means of FFT analysis. Furthermore, nonlinear vibration analyses were carried out to calculate the vibration amplitude and the orbit of the rotor above stability threshold speeds. Measurements were in good agreement with the linear and nonlinear stability analyses.

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The decentralized motion control architecture for multiple robots in coordination is a natural extension of human behaviors to robots. Decentralized motion control system for multiple mobile robots transporting a single object in coordination has been proposed and extended to nonholonomic tracked mobile robots driven by two actuators. Systems have an architecture of a leader-follower type, with which the resultant pose of the object is not uniquely determined. In this paper, we propose a new multiple robots system of the leader-followers type based on the function-allocation concept. To illustrate the concept, we developed a leader-follower robot system, in which the leader is in charge of the handling motion of the object and the followers avoid collisions to obstacles and handle the object in coordination with the leader. Experimental results will illustrate the validity of the proposed method.

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We have developed a new kind of repetitive control to reduce position error caused by both synchronous and asynchronous disturbances to disc rotation in optical disc drives. Conventional repetitive control greatly decreases position error synchronized with the disc rotation, but increases asynchronous position error. To decrease the asynchronous position error, a new method that averages control input signal every disc rotation has been incorporated into the conventional method. Experimental tests show that, at 9200-rpm disc rotation, the new control method significantly decreases the synchronous position error but does not increase the asynchronous position error. In other words, the new method achieves total position error 48% less than that of the conventional method (i.e., without using repetitive control).

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This paper addresses subjective evaluation for operating feeling in a haptic interface. The NASA-TLX method, which is mental workload index analysis, is employed to investigate operating feeling for various impedance parameters and task parameters. The result shows the existence of three patterns of human operation. The patterns correspond to viscosity-based operation, restoring force-based operation and inertia-based operation, respectively. We verify the existence of three patterns by analyzing force sensor data. Furthermore, the verification of three-pattern classification is also investigated by the semantic differential method and factor analysis.

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This paper describes path planning of grippers emulating human's grasping motions with respect to the thumb and index finger. When the hand approaches to the target object, the velocity patterns of the tips are bell-shaped regardless of the initial hand position. Path planning of two tips is similar to the obstacle avoidance against the target object and avoidance motion trends to be conducted by the index finger. Utilizing the obtained human characteristics, the path planning model is constructed in the complex potential field. As a result of simulation, it can be confirmed that the two tips separately go round the target object so as to approach the grasped part due to the artificial potential, and they move slowly in gripping process just like a human since each tip motion is based on the bellshaped velocity pattern.

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This study deals with an automated modeling method generating a finite element model of a bone from the cross-sectional images by a X-ray CT scanner. The modeling method is composed of four processes. The first provides a boxel space of a bone from the CT images. The second distributes nodal points in the space. The third generates tetrahedral elements with the nodal points using Delaunay triangulation. The fourth finishes accurately the model by removing excessive elements. We pointed out importance of layout planning of nodal points recognizing features of the bony shape. The proposed method distributes proper nodal points in the boxel space and produces the exact finite element model of the bone with desired total number of nodal points. We also discussed a method that controls size of elements according to bone density using CT values in the cross-sectional images.

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Following the previous report in which life style and physical characteristics of elderly people were discussed, the authors focus on the mobility tool for older drivers in this paper. "Silver Vehicle" concept is newly introduced in order to meet older driver's needs. The SV is a one-seater small EV whose maximum speed is limited to 30 km/h. Merits of the SV are discussed, and in order to examine its effects, a proto type of the SV was designed and manufactured. The proto vehicle whose characteristics were discussed in the 1st reports, was tested by the subjects, and as a result, it is shown that SV is suitable to older drivers.

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To evaluate further the car concept "Silver Vehicle (SV) ", which we have reported at the previous report, we performed "Town-Mobility Experiment" in Takanosu town, Akita pref. In Town-Mobility Experiment, a number of electric scooters and super small EVs were freely used in the center of the town by 64 elderly people. As a result of it, we learned that super small EV was very available for older people and had a great possibility for practical use. We concluded that offering S.V would cause to maintain elderly people's mobility (for example, to older drivers who may abandon to drive a car, possessing the SV brings improvement of their mobility), and could raise their QOL efficiently.

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A torque controllable viscous coupling is presented. The coupling consists of two types of discs with slits. One is connected to a housing (follower discs) and the other is connected to a shaft (driving discs). The driving discs and follower discs are arranged by turns and they are sandwiched. MR fluid is filled in the housing. Magnetic fields freeze the fluid, so that the shear torque is generated between the diving discs and follower discs due to shears between the slits in the discs under the magnetic fields. The torque is controlled by electromagnets. In order to have large torque with small electric power, coil turns have to be large, so that response delays due to inductance of the coil. A controller which improves response is presented. A method of control is presented which controls distribution of torque of rear wheel and front wheel.

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From the standpoint of energy and environmental problems, it seems that the power devices to drive directly the wheels of automobiles are changed over from conventional internal combustion (IC) engines to electric motors, whichever power source such as IC engine/generator systems, electric batteries and fuel cells may be used. In comparison with IC engines, electric motors have the characteristics that their torque response is rapid and their output torque can be observed exactly. Those make it possible to control the motor torque easily. In this paper, an acceleration control algorithm for an electric motor driven vehicle is proposed utilizing the above-mentioned characteristics, and how to reduce energy consumption without sacrificing its driveability is shown.

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We numerically investigated contact characteristics of a contact pad with rough disk surface and possibility of a contact/near-contact slider, using a single-DOF slider and random wavy surface model with random roughness. Contact characteristics are numerically calculated based on a modified Greenwood-Williamson model considering the macroscopic deformation of the surface. From the contact analysis, it was found that contact stiffness and other characteristics are determined by asperity contact until the contact pad penetrates into the upper standard deviation of asperity peak height and that the contact stiffness tends to approach a constant value as the pad penetrates into average asperity height because the macroscopic deformation becomes predominant. Using the above contact characteristics, we simulated the behaviour of a single-DOF slider over the random wavy surface for various values of nominal flying height from contact to near-contact regimes. Then we showed design conditions of disk waviness which can satisfy the tracking ability and wear durability in terms of wear volume and wear depth, and discussed the possibility and difficulty of a contact/near-contact slider.

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Genetic Algorithms have been studied widely to report their effectiveness in a variety of fields. As optimizer, they give us much privilege in considering types of design variables for multi-peaked problems. However, there exist some shortcomings, such as treatment of continuous variables, formulation of fitness function and the number of function calls. In the previous studies, we have been developed Adaptive Range GAs for continuous variable problem, by using RBF (Radial Basis Function) networks as approximation tools in solving large scale constraint optimization problems. From these results, we have shown the effectiveness to obtain good results. However, it is very difficult to give data within feasible region only by using random numbers for RBF and almost 80% of them are consumed in vain. In order to raise their ratio, we introduce SOM (Self-Organizing Map) as classification tools to choose data within feasible region. In this study, we will show the effectiveness of the proposed method based upon a famous benchmark test problem.

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This report concerns on the performance of leakage detection system for the coolant of nuclear reactor. The detection by Kalman filter is based on the change of total mass of coolant. Two points are analyzed: (1) The performance of this method is experimentally investigated by a bench-scale coolant system model. (2) The response time to detect is investigated by simulation under the condition of actual operation. This means that leakage occurres later from the system starting. The experimental result shows that proposed system can detect 0.06% loss of coolant. Therefore this method can be considered realizable. And by simulation it is cleared that occurrence of leakage in any time can be detected within 14 minutes. Comparing with the design target of the present system, this system is satisfying. Through above discussion, this system is concluded to be applicable and useful to an actual plant.

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The relief hole-type divided metal flow die forging process was adopted to fabricate the clad gear in this research. The influence of the deformation condition on the surface pressure and the metal filling into the die cavity were quantitatively evaluated. The purpose in the study is to obtain the optimum deformation condition from the viewpoint of reducing the surface pressure. In the experimental simulation of the die forging, an industrial pure aluminum was employed both for the inner layer material and for the outer layer material of the clad gear. The "2 step-type die forging process" and "Die forging process with mandrel" were adopted to realize the "divided metal flow state". As a result of the experiment, the following two points were clarified. (1) The filling performance of the "2 step-type" is higher by 20∼30% than that of "1 step-type" under the same pressure condition. (2) The pressure of "2 step-type die forging process" to perform the high metal filling into the die cavity is smaller than that of "Die forging process with mandrel". And the filling rate in the case of the mandrel projection height 4 mm is higher than that of 2 mm.

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The investigation of the cause of the segregation that arises during barrel finishing is desired, because the workpiece is not mixed with abrasives. Fundamentally, the motion of the workpiece and abrasives is equal to the motion of the discontinuous objects in the rotary barrel. Therefore, if the motion of the particles in the rotary barrel and characteristics of the segregation are known in various conditions, that knowledge can be used in order to investigate the cause of the segregation and the optimum machining condition. In this study, the bahavior of the particles in the planetary barrel which rotate about its horizontal axis and revolve around its vertical axis was examined through experiment and analysis using DEM (Discrete Element Method). As a result, it was demonstrated that the segregation was not generated by the relationship between length and inside diameter of the rotary barrel.

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A fundamental study on the electric erosion was carried out with a two-roller testing machine. A property of the electric current which flows between rollers was investigated under the condition of a rolling-sliding contact with the elastohydrodynamic lubrication. The influence of the impressed voltage on the wear of rollers was also investigated. Furthermore, a phenomenon which occurs in the gap between steel disks in the lubricant was observed with a CCD microscope in order to clarify the mechanism of an electricity flow through the elastohydrodynamic film. Experimental results show that the impressed voltage affects considerably the wear of rollers and the electric current flowing between the rollers.

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In order to clarify the lubrication mechanism of journal sliding bearing in a low rotational speed region, the relation between the friction coefficient etc and the minimum gap, which are defined between a shaft and a journal sliding bearing, has been obtained by the method of measuring the voltage between the shaft and the bearing for the minimum gap. As a result, it has been found that the friction coefficient largely decreases up to about 0.3 μm in minimum gap and almost shows constant after that with the increase of the minimum gap. Also, it has been supposed that the mixed lubrication state, where the surface asperities of the shaft and the bearing partially contact each other, continues up to about 15 μm in minimum gap because of the rotational deflection of the shaft.

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B-C-N films were prepared on single crystal silicon substrates by RF magnetron sputtering using a composite target of diamond and cBN powder. The target was mounted on a RF magnetron cathode, then sputtered by nitrogen and hydrogen gases. The hardness of the B-C-N film increased with increasing hydrogen flow rate, corresponding to a maximum at 10 cm³/min, followed by a drop above 30 cm³/min. The film was stable for a long time when it was deposited at the substrate temperature of 500°C. Auger electron spectroscopy and elastic recoil detection analysis revealed that the carbon content in the B-C-N film decreased with increasing the substrate temperature. Furthermore the B-C-N film didn't show the significant weight change under the heat treatment test at 500°C in the air, and the hardness of the B-C-N film remained constant up to 500°C, whereas the DLC films were disappeared after the test at 500°C. These results suggest that the B-C-N film has the potential to be applied to the tribological coatings under relatively high temperature conditions.

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Fabricating a part from sheet material not bulk is a good method from view point of energy consumption for processing and lightening the weight. Usually, deformed part from sheet material has almost constant thickness and sometimes needs to strengthen locally. One method for strengthening is to increase the thickness. First in this study, thin aluminum pipe was compressed longitudinally for thickening in a die. The pipe with large length buckled like bellows. The limit length without buckling was small and only from 3.5 to 4 times compared with the thickness. Then, clad pipe with two materials of aluminum and stainless steel was worked in the die with mandrel. The buckling behavior varied surprisingly according to the position of the two materials. In clad pipe of outer stainless steel and inner aluminum, the buckling behavior was almost the same as aluminum single pipe. However in clad pipe of outer aluminum and inner stainless steel, the outer aluminum deformed without space between the die and the workpiece, but the inner stainless steel buckled and deformed like bellows. By this new processing, we could get smooth outer surface with no defect and a structure of large elastic rigidness simultaneously.

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Conventional magnetic abrasives have been used in magnetic field assisted machining process for internal precise finishing. However, it is difficult to machine internal surface of large diameter or thick container, joint of circular pipe and gas bomb head. In this paper, a kind of new magnetic field-assisted machining process using magnetic machining jig was proposed. The magnetic machining jig consisting of steel or permanent magnet wrapped with abrasive paper, as a tool instead of the magnetic abrasives. In contrast to the magnetic field-assisted machining process, the magnetic machining jig can generate higher magnetic force than magnetic abrasives because of higher material susceptibility, achieving the higher finishing efficiency. The advantage of using magnetic machining jig was clarified. Then, a kind of new machining jig used a pair of magnets was proposed, the high-efficient machining and stability was realized. Moreover, the model experiments are completed and the possibility of internal surface machining for thick container is confirmed. The processing principle and the machining characteristics were discussed.

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This study deals with the development of a method to machine a diamond. This method utilizes tool wear of a diamond during cutting process of carbon steel. A three-dimensional shape of diamond has been successfully obtained by the present method in less than one minute. The study in this paper is concerned with the machining rate of a diamond when the crystallographic orientation of a diamond is (1, 0, 0), (1, 1, 0) and (1, 1, 1). The machining rate is best in the case of (1, 1, 0) plane, next in the case of (1, 0, 0) plane, and less in the case of (1, 1, 1) plane. The removal rate of a diamond by the present method is much larger than that by friction between diamond and carbon steel. Some samples of machined diamond by the present method are shown in the end of this paper.

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The study deals with the automatic chamfering for the workpiece with complex shape on the basis of CAD data, using an industrial robot. We have already developed a system named TA-DRPECS-tool path, pushing direction and force at the each chamfering point are calculated from CAD data both to keep chamfering conditions stable and to keep a larger range in space for workpieces with complex shape. As a chamfering tool, a rotary-bar type tool is attached with "intelligent holder". The holder consists of a force sensor and two linear actuators to realize smart force control. In the article, improvements of the holder to increase a controllability and to expand workspace of the robot are reported. From results of experiment to chamfer curved edges of intersected throughholes, the system is found to be effective to chamfer edges of a workpieces with complex shape.

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The study deals with the development of a practical process planning system to remove and finish burrs existing in cast workpieces. There are many processing methods in accordance to variety of materials and cast workpiece shapes. The selection of processing methods has been made by skilled workers since processing methods and their knowledge are not systematically classified. In addition, as burrs on workpieces are not necessarily kept constant, and the performance of deburring and finishing tools deteriorates by abrasion of tools, they make the automation and optimization of the works extremely difficult. In terms of achieving the total automation of manufacturing system, the systematization of deburring and finishing works is indispensable, but, has not been realized due to the lack of compilation of important knowledge concerning workpieces to be deburred, deburring tools, deburring condition, etc. Thus, a knowledge database was constructed by classifying workpieces and extracting processing methods. A process planning system was developed by making use of knowledge database. As a result, it is found that the system can offer the appropriate process plan in terms of minimum cost or shortest processing time.

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Although conventional three-dimensional CAD systems are useful for modeling the geometry of products, the support function for design itself is lacking on the systems. In the present paper, to achieve the concurrent working between the consideration of machine design and its geometrical modeling, an idea of the modeling based on design intention, that is named intention-driven modeling, is proposed. The concept is expressed through object-oriented expression of design knowledge. A prototype system is developed to demonstrate examples of top-down design and modeling of products from conceptual design stage. The system brings such benefit that the designer can concentrate the attention on the thinking for design.

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This study deals with the model of the flow shop of multi-stage machining process. It proposes the method of searching for the optimal scheduling of the machining process about this model. First, the method for the temporary scheduling is proposed by gathering the machining processes time of the multi-stage machining process to 2 temporary stages. Next, the optimal scheduling is calculated by confirming back and forth relation about 2 products from the temporary scheduling. According to compared between the proposed method and the conventional Branch and Bound method through the examples of numerical value computation, it is obvious that the proposed method is attained the optimal solution in the number of times which is much less than the conventional Branch and Bound method is attained.

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It is reported that clean steel with low oxygen content may be effective to improve the fatigue strength. In this paper, the bending fatigue tests were carried out for carburized gears made of clean steel and ordinary steel with oxygen content of 5 ppm and 8 ppm, respectively. After removing the nonmartensitic layers by electropolishing, the fatigue strength of the clean steel gear is 28% higher than that of the ordinary steel gear. To discuss the influence of cleanliness, the authors estimate the fatigue strength considering the distribution of inclusions. The maximum size of inclusions in the dangerous volume of gear tooth, which is calculated according as the stress distribution of fillet including the position of crack initiation, is estimated by the statistics of extremes. Then the fatigue strength is estimated by using the maximum size of inclusion and the estimation formula proposed by the authors.

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