[in Japanese]

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Cutting tests with ceramic tool are performed on hardened S 45 C steel billet at high temperature by using flame heating method. Hardness on the work surface, cutting forces, tool life, roughness on the work surface, chip, and other pertinent data are taken.
Tool life test is conducted from room temperature to 500°C work temperature and other test are conducted from room temperature to 600°C work temperature.
The results showed that tool life is increased with the rise of work temperature but hardness on the work surface is linearly decreased with work temperature. Also, it is pointed out that the optimum heating temperature for hardened carbon steel will be 200300°C.

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Logarithmic scale weighers are advantageous for equalization of accuracy as per cent of true value and simultaneous indication of weight and cost. In this paper, the writer treats the following methods to get the logarithmic scale weighers by the application of (1) cam type detectors and (2) a linkage transformer with inclined lever detectors. By the second method, the accuracy of ±0.0003 has been got theoretically and ±0.001 practically.

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The mechanism of pressure generation in hydrospark was theoretically analyzed, assuming the polytropic relationship between the pressure generated by hydrospark and the travel distance of the ball in a specially designed shooting type hydrospark device. It appears that the pressure was produced by hydrospark owing to the expansion of high pressure vapor generated between electrodes.
In the authors' experiments, the expansion ratio was about 300 and the polytropic index for the vapor generated between electrodes was 1.24 for the electrode distance of 3.85mm and the discharge energy of 4000 Joules.
The composition of gas generated between electrodes in hydrospark was 99:1 to 9:1 for liquid vapor vs. metal vapor of electrodes.
The strain rate of metal deformation by hydrospark forming was theoretically analyzed, though not in detail.

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We studied the influence of discharge current-shape in condenser discharge machining. In order to change the height and width of discharge pulse, resistance and inductance were inserted in the discharge circuit. Then the erosion efficiency increased and electrode wear decreased considerably. It was also found that from the result of single discharge or slow repetition discharge we can assume the high repetition phenomena.

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Effects of induction hardening conditions on the residual thermal and quenching stresses were examined with the circular discs hardened from their periphery. Principal results are as follows :
A. Residual thermal stress
(1) When the gradient of the heating temperature distribution is steep, the tangential stress σ_t is compressive in the inside region of the disc and tensile in the outside region. The radial stress σ_r is compressive in all regions. (2) As the gradient of the heating temperature distribution is gradual, the region where the tensile stress σ_t is brought about moves to the inner side of the disc. (3) In the outside part of the disc, the curve of σ_t assumes an upward form. (4) Regarding to the stress in the inside only, as the steepness of the heating temperature gradient becomes gradual, the value of the compressive stress σ_t once increases and then decreases, and with very gradual gradient it turns to the tensile.
B. Residual quenching stress
(1) σ_t is compressive in the outside part of the disc. (2) When the gradient of the heating temperature distribution is steep, large tensile σ_t exhibits in the part neighbouring to the hardened layer.

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The starting behavior of the thrust ball bearing is observed by the especially designed test apparatus.
The following facts are found : (1) The compliance of the rotating angle with the rotating torque is shown by the complicated curve. (2) Owing to the shift of the initial relative position of the steel balls and races, considerable fluctuation of the starting torque is found. (3) The experimental relation between the starting torque and the thrust load is expressed by the equation M=kTⁿ, n=1.37, k=0.081 (nonlubricating), k=0.051 (lubricating), where M: the starting torque (dyne-cm), T: the thrust load (g).
The facts (1) and (3) are interpreted and discussed by the tangential elastic displacement and the interfacial slip at the area of contact between the steel ball and the rolling groove of the bearing race. On the cause of the fact (2), some discussion is made taking account of the state of the surface of the rolling groove.

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The measurement of accumulative pitch error is one of the most important items in accuracy measurement of gears.
However, by the conventional methods the time for measuring is long and it is very difficult to measure fine pitch gears (m=0.11).
To solve the above-mentioned problems, a new measuring method combining a gear type condenser with an involute helicoid worm has been developed.
The gear to be measured is accurately indexed by the worm, the pitch errors are detected with the condenser.
It has been confirmed by the experiments that the accumulative pitch error can be measured with high accuracy by this method.
For an indication of the accuracy of this method, a hobbed spur gear was measured by this method and by the conventional Carl Zeiss gear tester.
The obtained data agreed within 3μ. It is not surprising to have a nominal difference such as this if the tooth profile errors are taken into consideration.
Also, the time for measuring reduced from 35 to 5 minutes.

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In our experiment, the machining of polygonal profile is performed by the relieving lathe which is prepared for this purpose.
Eccentric disk cam is used for the forward stroke of the lathe tool and compression spring is used for the return stroke.
In this case, the stiffness of the spring influences to the accuracy of machined polygonal profile.
If the compression of spring is too weak, unaccurate profile is resulted. On the other hand, the excess compression results the temperature rise on a large scale and damages the important mechanisms.
In this paper, we assertained the relations between the stiffness of spring and the accuracy of the machined profile.
The conditions of operation for the best accuracy is determined from these experiments.
Results we get are as follows :
The compressive force of the spring should be employed more than 6 times of inertia force, and more than 3 times of frictional force.

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