This paper describes a study on the effect of lubricants on the rolling friction produced when a hard steel ball rolls between two parallel flat plates. The main results obtained are as follows. (1) When the rolling contact surfaces are lubricated with a small amount of the oil, the lubricants surely decrease the adhesion acting on the contact surfaces, so that according to the oil film strength, the lubricants reduce the magnitude of the rolling friction which is due to the separating resistance on the contact surfaces. (2) But when the contact surfaces are lubricated with excessive quantities of oil, because of the viscosity and the surface tension, the lubricants does not reduce the magnitude of the rolling resistance. (3) After all when the two effects are compensatory, the rolling frictions remain nearly constant for both lubricated and unlubricated surfaces.

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This investigation was made for the purpose of ploring the probability that the grinding state was tomatically diagnosed. As one possible approach the problem, the pattern recognition technique is adopted. In this study a pattern classifier, which the overall grinding sound pressure and the sound pressure radiated from grinding wheel were contained as the characterizing parameters, could be derived through the nonparametric training process. According to the discriminant results, by the pattern classifier trained, the change of grinding state could be perceived before the grinding burn or the chatter occurred.

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In this paper, lapped spot welding of Al plates is examined and the influence of experimental conditions on the weldability is discussed. The microstructure and the microhardness in welded part are investigated. The obtained results are as follows : (1) Welding strength is able to be summarized by power density (W) independent of welding conditions. Welding begins at W=300 kW/cm² and the maximum strength is obtained in the range of W=700-800 kW/cm². (2) The molten configuration depends upon irradiating conditions regardless of the thickness of two plates. Therefore, the welded area and the welding strength depend upon only the thickness of upper plate. (3) The microstructure of welded part shows the fine cast structure. The welded part has high microhardness and shearing strengh equivalent to cold rolled bulk. After annealing, the welded part does not become soft and the welding strength does not decrease.

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This paper presents static rigidity of hydrostatic ead-screw which has modified thread profile. Hylrostatic lead-screw has the following merits, i, e, no stick-slip, no wear of screw thread flanks and soon. On the contrary it has a defect of difficulty of machining recesses. In this study, considering that crapezoidal thread supports thrust force and that criangle thread supports radial force as well as chrust force, the thread profile is decided to have a modified thread form. In order to get it easy to make the nut which has four divided recesses, the method of four divided nut is applied. As a fundamental study, an annular rotor type thrust hydrostatic bearing was made and static rigidity is investigated. Based on this result, a practical hydrostatic lead-screw is made. As a result of examining static rigidity, it is ascertained that experimental rigidity of rotor type hydrostatic bearing agrees with theoretical one by compensating structural rigidity and that experimental static rigidity of practical hydrostatic lead-screw agrees with theoretical one comparatively well.

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The influence of disengage angle upon the initial fracture of tool edge has investigated with the orthogonal interrupted cutting, and the relation between the initial fracture and the disengage angle under various cutting condition are sought and the transient cutting forces are measured at the sametime. The main results are as follows. The initial fracture of tool edge occurs at the specified disengage angle, and then, the negative shear plane arises on the exit surface of work and only the normal component of cutting force for the rake surface acts to the tool edge. Therefore, it is supposedthat the initial fracture of tool edge is brought about to that force.

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This study has been conducted in the stage of developing applied functions in machine design system HIMADES-1 whose basic functions were already reported. In the machine design system, the object of which is not only an individual part but a whole machine, it often occurs that after modifying a certain dimension of a part in some machine unitother dimensions related latently to it should be modified simultaneously. This design activity is called as dimension matching in a broad sense. In the present paper, the dimension matching algorithm. is introduced that is based on linear conditional equation of machine structure. The main part of this algorithm is automatical generation of the above equation, and the mathematical method to carry it out is mainly described. Finally, some examples of application to some units prove that the works of man side are extremely lightened.

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In grinding the helical cutting face of a gear hob, the cone-shaped surface of a grinding wheel is widely used. It has been clarified that the grinding wheel surface should be convex to produce the correctly helical cutting face of a gear hob. The rigorous equation and the approximate formula to calculate the profile of the grinding wheel have already been obtained by one of the authors. But no precise analysis has been made on the problem of interference of the surface of a grinding wheel withthe helical cutting face of a gear hob. In this paper, the process of interference is firstly analyzed by the characteristic curve between the helical cutting face of a gear hob and the surface of a grinding wheel. Secondly is shown the method to calculate the critical cutter pressure angle over which the interference can be eliminated. Then the theoretical profiles of the cutting face of the hobs are certified to coincide well with the experimental ones. Finally, the approximate formula to calculate the grinding wheel profile is confirmed to be accurate enough by the numerical calculations of both the approximate formula and the rigorous ones.

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