The preload of the ball screw, applied between two nuts, is necessary for its high rigidity and accuracy. However large preload increases frictional resistance. Therefore, at high revolution, the temperature of the ball screw rises remarkably and its thermal expansion lowers its feed accuracy. The purpose of this study is to construct the device that can rotate the ball screw at high revolution, to measure its temperature rise and thermal expansion, and to analyse these results by heat transfer theory. In this experiment, preload, given by helical springs between two nuts, is constantly 980 N or 1 960 N. By this analysis, the boundary heat transfer coefficient of the ball screw is determined, and axial temperature distribution in steady state is nearly estimated.

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This report represents optimization techniques to evaluate the cylindicity according to ISO and JIS. Such the direct search methods as improved simplex method and Powell's method were applied and the algorithms were studied. Consequently, it was made clear that the new algorithm for improved simplex method, which was developed in this research, was the most effective from the view point of the calculation time and the accuracy of cylindricity.

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The occurrence of the forced vibration induced by the intermittent cutting becomes an important problem during the gear cutting by using both a hob and a hobbing machine. The torsional vibrational characteristics for the rotational transmission mechanism of the employed gear hobbing machine are related strongly to this problem. In the previous report, it is ascertained that both the high-rate and high-accuracy gear cutting was attained by examining this characteristics experimentally. On the other hand, the manufacturers of the hobbing machine must analyze the torsional vibrational characteristics of the given rotational transmission mechanism to improve the design and do the optimum design of that mechanism in order to enable both the higher-rate and the higher-accuracy gear cutting. However, there is no research for the torsional vibrational characteristics of the gear hobbing machine up to date because the analytical method of the torsional rigidity for the complex rotational transmission mechanism has not been developed. In this report, the whole rotational transmission mechanism is modeled by the four kinds of elements which are composed of the inertia moment element (that is, gear, pulley and flywheel etc.), the torsional beam element (that is, rotational shaft etc.), the engagement spring element (that is, gear engagement and belt etc.) and the resident element (that is, journal bearing and table guide surface etc.). By applying the computer program to superpose the dynamic stiffness to this model, the method to analyze both the torsional static and the torsional vibrational characteristics of the rotational transmission mechanism was newly developed. Also, by the developed analytical method, both the vibrational mode and the energy distribution in each natural vibration which becomes the standard to improve the design can be obtained. This analytical method is applied to a small size precision gear hobbing machine (having the worktable diameter of 360 mm) which is one of a specific type widely employed in gear production shops. As the result, it is ascertained that the analyzed result agrees well with the experimental one.

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In this paper, at first the relation between the optimum interferences and the fatigue limit have been exmained when the press-fit of bushings are represented by interferences. Then the influences of the number of links on the fatigue strength have been examined, and studied statistically. The results are as follows: (1) The effects of the press-fit of bushings could be estimated by fatigue limit diagram of roller link-plates without interference. (2) The optimum interference exists that gives the most improved fatigue limit of roller chains. (3) The fatigue limit of any number of links could be estimated statistically by the life distribution of roller link-plates. (4) The tensile strength, the fatigue strength at N cycles and the fatigue limit decrease, as the number of links increases. And the ratio of decrease is in order of fatigue limit, fatigue strength at N cycles and tensile strength.

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The stylus method is analyzed theoretically by a statistical approach for the purpose of clarifying the effect of stylus shape on the measured grain cutting edge density seized by the stylus, and the degree of agreement is investigated experimentally between the measured grain cutting edge density by means of stylus method and that obtained by means of scratch method. Results are summarized as follows: When using conical stylus, measured density of grain cutting edges seized by the stylus is not identical with that of grain cutting edges existing within the grinding wheel, so that a relationship equation between the two is derived the oretically. When using knife-edged stylus, meas ured grain cutting edge density obtained by the stylus agrees with the grain cutting edge density in the grinding wheel approximately, although the agree ment is limited in the grinding wheel surface layer The limited depth of grinding wheel varies win width of knife-edged stylus and 0.3 mm is obtainec as an appropriate width. Experimental results o wheel surface topography by means of stylus methoc show an agreement with those obtained by means of scratch method in the grinding wheel surfact layer.

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The thermal deformation of a workpiece is in close relation to the machining accuracy of a grinding process. Here, experiments were carried out in plunge-cut surface grinding to clarify the effects of thermal deformation on the accuracy. The flatness of a ground surface and the temperature distribution in a workpiece were examined under various grinding conditions. Moreover, a numerical model was constructed to simulate the temperature distribution during the plunge-cut grinding operation. From the results, it can be said that the flatness is linearly proportional to the temperature difference in the workpiece, independently of grinding conditions, and that the accuracy is qualitatively predicted by a numerical simulation of the temperature distribution.

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This paper describes a study on an application of knowledge engineering to CAD. In machine design, the conceptual designing is important but not easy to use computers to help designers, though CAD systems were widely introduced to the detail design stages. This is mainly due to the facts that the nature of the conceptual designing stages is not clarified and that how to represent machines and how to manipulate knowledge are not obtained. For these reasons, it is necessary first to define the representation of the specifications and of the de-sign solutions suitable for conceptual design stages. Then, the inference rules can be defined. In this paper, these rules, originally defined in the first order predicate logic form, are expressed in production systems. A pilot system for the conceptual designing stage is developed using the methods of knowledge engineering. This system, called PROSCODE-1 (PROduction rule System for COnceptual DEsign), is a knowledge-based system that is able to get a conceptual design solution in part-connectivity graph from a specification written in power flow. It is found that use of this kind of systems is convenient and useful for designers, especially when development of the designing process causes many changes.

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Plunge grinding process of some fine ceramics is experimentally analyzed with metal bond diamond wheels, investigating wheel wear, grinding force, surface roughness, grinding ratio and so on. The wheel wear of diamond wheel becomes larger in the order of alumina, silicon carbide and silicon nitride, and wheel wear in alumina is as much as that in SCM 435 steel. Furthermore wheel wear increases with increasing setting depth of cut, speed ratio of work to wheel and grinding speed. Grinding force becomes higher in the order of silicon carbide, alumina and silicon nitride, and grinding force in silicon carbide is less than that in SCM 435 steel. Grinding force increases with increasing setting depth of cut and speed ratio and with decreasing grinding speed. Surface roughness is mainly affected by grain size of diamond wheel, but not affected by work materials of fine ceramics or grinding conditions such as setting depth of cut, speed ratio and grinding speed. Grinding ratio which indicates grindability of work materials becomes higher in the order of silicon nitride, silicon carbide and alumina of normal sintering ceramics, and that of reaction sintering silicon carbide becomes lower.

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A new method is introduced for evaluating form errors of a workpiece such as the straightness in a plane, flatness, roundness and cylindricity. By the method, the minimum zone containing a measured feature can be determined and then the least possible value of the form error can be obtained. The method is a generalized one applicable to various types of form error evaluation and is useful in the case where the value of the form error is close to that of a specified tolerance. A theoretical background of the method, fundamental formulas used in it and assumptions on which it is based are discussed. Numerical examples of evaluation are shown for the straightness, flatness and roundness. Experimental evaluations of the cylindricity error for three workpieces are also carried out. A comparison is made between the form errors and the evaluation times by the method and those by the least squares method.

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Selection of the duration of the impulse force and the frequency range to be set on the FFT analyser are discussed in view of obtaining reliable structural dynamics data by impulse response tests. Besides prior knowledges about the frequency spectra contained by the impulse force, and the sampling rate required for the accuracy of the data processing, present study took theoretical and experimental analysis into the amount of mechanical energy input to the structure under test by applying an impulse. Practical guide line for performing the impulse response test is given as the result of the study.

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This paper presents a unified method dealing with dimension matching and motion analysis, both of which play effective roles in the primary stage of machine design. This method mainly consists of automatically generating the general conditional equations of machine structure (CEMS) and solving them. The CEMSs are derived from the geometrical restriction on a closed loop of volume-elements which are fixed or movable but connected with each other, and are expressed with two types of variables, that is, static and dynamic dimensions. Usually, the formers are called as merely dimensions and are treated differently from the latters representing motions. But, when the formers are needed to be modified with the condition that the whole topology should not be altered, they behave entirely in the same way as the latters. Thus, dimension matching and motion analysis have much in common and differ in only that which variables should be chosen as unknown ones in the CEMSs. After they have been chosen, the equations are solved by the Newton-Raphson method in both cases. Although the whole algorithm is highly sophisticated, an interactive subsystem has been developed, with the aid of HIMADES-1 whose data structure is mainly designed for these applications.

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A precision X-Y stage has been developed for step and repeat type lithography systems, such as optical reduction projection exposure and electronbeam writing systems. To achieve both high-speed and high-precision, the stage incorporates a dual stage system consisting of coarse-and fine-tables. The coarse-table has a unique mechanical structure utilizing a PTFE slide-bearing guide. To reduce the moving mass of a table, it is designed that only a table moves on an X-Y plane. The table is driven by DC servomotors and ball-screws. These X and Y-axis drive mechanisms are both fixed to the same base. The coarse-table moves at a maximum velocity of 100 mm/s, and is positioned within ±5 μm of a desired position. The fine-table is driven by three piezo-electric actuators, and moves precisely along the X, Y, and θ-axes so as to correct X and Y-axis positioning errors and yaw with the coarse-table. Positioning of these tables is carried out with a closed-loop control system using a 3-axes (X, Y and yaw) laser interferometer measurement system. A ±0.05 μm positioning accuracy, a yaw of less than ±1 μrad, and a 200 ms move time for a 10 mm step is achieved.

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