[in Japanese]

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In the first half of the paper an initial surface model is presented for a surface design of which the shape is quite different from that of a surface of revolution. This model is the 3rd initial surface model in the design method the author proposes. This initial surface model can be generated by two intersecting curves. A new surface fitting technique is introduced as well in the generation process of the initial surface model. In the last half a projection method is proposed to control the surface shape which has been generated by one of three types of initial surface generation methods. A patch boundary global curve is projected onto an arbitrarily specified plane. By controlling the projected curve the corresponding surface part is modified.

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This paper explains the relations from the effects of the loading and the retreat of grinding wheel face in the grinding domain of perfect self-sharpening. The grinding ratio becomes small with loading and to be make the area ratio (the ratio of the work area to the wheel area) small. The limited metal removal rate is found in the maximum of the metal removal rate in case of small area ratio and in the least depth setting and feed rate of the perfect self-sharpening in case of large area ratio. The optimum values of the grinding wheel velocity exist to the grinding ratio and the metal removal rate. The effects of each grinding variables on the grinding ratio and the limited metal removal rate are described in detail. And, the specific grinding power becomes small with the grinding ratio without effect of grinding wheel velocity. The ratio of normal grinding force to tangential grinding force is constant without reference to variation of grinding wheel velocity, feed rate and cutting depth.

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In the interferometric measurement of surface roughness, its sensitivity can be enhanced in case of using the principle of “amplification of multi-reflection optical path difference”. Therefore two types of the high sensitivity interferometers are made for the purpose of measuring a more precise finishing surface. One is moire-fringe observation type microinterferometer which can decrease “walk-off” for special phenomena of multi-reflection, the other is multiple-beam high sensitivity microinterferometer which can raise “reading accuracy” by sharpening the fringe in addition to high sensitivity. In these two methods, it is experimentally assured to obtain some times (4-5 times in this experiment) sensitivity compared with the conventional types, and it becomes possible to measure a finer precision surface.

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In this report, at first the effects of pre-loading and the press-fit of bushings on the fatigue strength of roller-link-plates are investigated separately, and then the combined effects of these are investigated. The effects of pre-loading on the fatigue strength of roller chains are also investigated. The results are as follows :
(1) The fatigue limit of roller-link-plates improves, as pre-load increases.
(2) The optimum condition of press-fit of bushings exists and gives the most improved fatigue limit of roller-link-plates.
(3) The fatigue limit of roller-link-plates with press-fitted bushings improves still more, when they are pre-loaded.
(4) The theoretical values on the fatigue limit of pre-loading and press-fit of bushings tend to agree with the experimental results.
(5) The effects of pre-loading of the fatigue limit of roller chains can be estimated from the combined effects of pre-loading and press-fit of bushings of roller chain link-plates.

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This paper presents a finishing method of a cylinder based on the three-point measuring method of roundness. The principle of the finishing method is theoretically considered. In the three-point measuring method with a V-block, a value of f f [=1+cosn (90°+θ/2) /sin (θ/2)] means a magnifying power of measurements, where θ is the angle of the V-block and ii is a number of the polygonal cross section of the cylinder. The value of f can also determine whether the roundness of the cylinder can be measured or not, because in the only case of f≠0 the roundness can be measured. A cylindrical specimen is finished by a double threepoint method with two angles (θ=60° and 180°) having a value of f≠0 for each of n (=2, 3 and 4). A final out-of-roundness was less than 0.2 μm by the new double three-point lapping machine. Merits of this finishing method are as follows : 1) The finishing procedure is simple and inexpensive. 2). The out-of-roundness of a specimen finished by the new lapping machine is not influenced by the accuracy of the lapping machine itself.

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In this report, it is analyzed that a super precision machining in long and small diameter's hole boring can be realized by combining the main spindle system with the hydro-static bearing and the effect of improvement of the boring bar's rigidity using the insensitive vibration cutting mechanism. For this long hole boring, a new special ultrasonical torsional vibration boring device can be created. This device fixed on the carriage of the newly developed vibration cutting lathe enable to bore a hole of 12 mm in diameter and 90 mm in length. This analytical result has been confirmed by the experiments under the many cutting conditions. The main cutting conditions are as follows : the vibrating direction of tool ; in the same direction as that of cutting, frequency; 29.3 kHz, amplitude; 20 μm, cutting speed; 8-20 m/min, depth of cut ; 0.005-0.03 mm, feed; 0.02-0.08 mm/rev, cutting tool material ; carbide tool K 10, tool geometry; rake angle, 0°, 10°, 20°, duralumin σB=28 kg/mm, brass σB43 kg/mm, carbon steelσB= 66 kg/mm, are used as work materials. The main results are as follows : 1) A new special ultrasonical torsional vibration boring device for long and small diameter's hole boring can be created. 2) Machined surface roughness almost coincides with the theoretical roughness. 3) Roundness of 0.8-1 μm are obtained. 4) The smooth machined surface on which iridescent surface is generated is produced. 5) By this study, it is proved that this new lathe has the possibility of super precision machining in long and small diameter's hole boring.

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It is well recognized that the skill of tool motion and cut arrangement not only governs the efficiency of rough turning but also affects the cutting sequence and tooling. In the automatic plogramming system for turning “MELTS” which is featured by its higher level of technical automation, especially the determination of tool motion and cut arrangement constitute an important part. This report treats with the algorithm which automatically determines the direction of tool motion and arranges the way of cut including the stock allowance referring to blank and part contours. The algorithm has been implemented by summarizing and systematizing the know-how obtained from skilled operators and process planners throughout the country.

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Forced vibration characteristics in closed reed conditions are clarified whereby external vibrations cause closed symmetrical and unsymmetrical reed switches to open. Phenomena where closed reeds are opened are caused by vibrations of reeds in the 1st clamped-pinned mode and rebounding of reeds induced by cyclic collisions at reed ends. The states are realized when colliding velocity is sufficiently large comparing to the contact force. Acceleration amplitude necessary for causing closed reeds to open is proportional to their contact force. In symmetrical reed switches, this amplitude decreases with reed overlap ratio. The amplitude in unsymmetrical reed switches is equivalent to that of symmetrical ones with 0.025 overlap ratio. Experimentally, determined amplitudes in transient excitations range from 15 to 70 G. Then, without extremely violent collisions, reed switches are sufficiently stable against external vibrations.

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Wear experiments were conducted with single and polycrystalline ferrites sliding on a cast iron disk on which an oil containing abrasives (1000, 4000 and 6000 mesh) was applied. The resulting wear surfaces were examined with electron diffraction, electron microscopy from replica and etching-rate method. Results of the investigation indicate that, for the single and polycrystalline ferrites, the deformed crystalline layers were exhibited by the Raether model in metals. The depth of deformed crystalline layer of ferrite, for the 1000 mesh abrasive of silicon carbide, is 2. 5 to 3 μm. It also, for the 4000 mesh or the 6000 mesh abrasives, is O. 8 to 0.9 μm. Surface cracking occurred as a result of sliding. The single crystal ferrites exhibited the same cracking depth as the deformed crystalline layer. The degree of cracking for the polycrystalline ferrites was more than that seen in single crystals. This is due to cracking along the grain boundaries of ferrite. In addition the wear mechanism of ferrite is discussed. Two wear mechanisms were observed. One was brittle fracture such as cleavage and quasi-cleavage on the 1000 mesh abrasives as a result of plowing and rolling of abrasives. The other was deformation in a plastic manner such as micro-cutting on the 4000 or 6000 mesh abrasives.

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In this investigation, a new machining apparatus is presented to form chips intermittently even an external cutting operation, not to form continuous chips such as in turning. Subsequently, some considerations on this machined surface are reported. This technique is the external cutting as if a shell end mill circumscribes about a rotating workpiece, while the tool or workpiece is given feedings to necessary directions and even continuous chips are formed intermittently into a certain shape by up or down milling. In order to investigate a possibility of the practical operations the tool is mounted on an arbor clamping in a lathe chuck and a workpiece-rotating apparatus is only made, without making a special cutting apparatus. Therefore, the workpiece is given feedings along its axial direction and cut by up milling. Accuracy of shape, dimensional accuracy, and quality of surface roughness should be sensitively affected by the type of machining technique and by both the stiffness and rigidity of tool, machine, and workpiece. According to this experiment it is clarified that one can obtain fairly good quality of surface roughness at least.

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By a programed variation of the spindle speed of machine tools, it is possible to control the onset of the regenerative-type self-excited chatter. In this paper, the effect of the wave form of spindle speed variation and the practical improvement of the metal removal rate in this method are theoretically analyzed, and the results are verified by some turning experiments. The results obtained are as follows. (1) Among various waves such as rectangular wave, sinusoidal wave, triangular wave and multi-stepped wave, the triangular wave is the most effective as the mode of spindle speed variation. (2) By means of complex method, it is possible to find more effective wave form of spindle speed variation theoretically. (3) If the dynamic characteristics of the cutting process and the machine tool structure are known, it is possible to predict the maximum allowable depth of cut under varying spindle speed.

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The paper proposes an analytical method which enables to predict crater wear of carbide tool in conventional turning operation under various cutting conditions, based only upon the data of orthogonal cutting mechanics and results of a single tool wear test. It is possible to predict cutting force and chip formation for single point tool of arbitrary shape by using the energy method and the three dimensional cutting model developed in the previous paper, when the orthogonal cutting data are in hand. By using the predicted results together with an assumption made on the stress distribution on rake face, the temperature distribution on rake face is obtained through a numerical analysis as reported in the previous paper. Computer simulation of crater development is then carried out by applying the wear characteristic equation established in the previous paper, of which characteristic constants are obtained from a single wear test, and the predicted distributions of the stress and the temperature as well. It is found that the overall agreement of the predicted crater with the actually measured one is good both in depth and contour, however, there exist some discrepancies in the location of the deepest portion of the wear.

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In order to examine whether the hysteresis loss hypothesis can be applied to the rolling friction of the tempered ball bearing steel, the effect of the tempered structure of SUJ 2 on the pure rolling friction and the yield behavior at low strain values are experimentally studied. The pure rolling friction varies with the tempered structure and corresponds with the yield behavior, and it is nearly proportional to the amount of retained austenite if the property of martensite remains constant. From these results, it is confirmed that the pure rolling friction results from the hysteresis loss of the material even if its metallurgical structure is varied by tempering. On tempering at the temperature lower than 300°C, the pure rolling friction is caused by micro-plasticity of the mixed phase structure consisting of martensite with high yield stress and retained austenite with low yield stress, while it is caused by the plastic flow of martensite with low yield stress on tempering at the temperature higher than 300°C.

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