Transactions of the Japan Society of Mechanical Engineers

Relations between the Dispersion of Balance and the Roughness of the Surface of Knife Edge and Flat Bearing

Ryuichi MASUO, Chikayoshi MAEDA

1960 Volume 26 Issue 172 Pages 1709-1713
Published: December 25, 1960
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.26.1709

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As the causes of the dispersions in the measurements with a balance, we considered the roughnesses of the knife edge and the flat bearing. About this problem, we made a thorough research on various knife edges, and as a result the following formula was found. σΔW=W/L·α·b where σΔW is the standard deviation of dispersions, W is the load supported by the knife edge, L is the distance between center and end knife edge, α is a constant, b is the breadth calculated by Hertz's equation. However, the roughness of the knife edge, and the flat bearing treated in our preceding reports, was nearly constant, consequently α was nearly constant, α must be the function of the roughness, so we changed this time the roughness of the flat bearings in a wide range, and observed σΔW. We found two essential sources of the dispersions as well as the quantitative relations between them.

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Research on the Elastic Fulcrum of the Balance

Ryuichi MASUO, Chikayoshi MAEDA

1960 Volume 26 Issue 172 Pages 1714-1719
Published: December 25, 1960
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.26.1714

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In our considerations, the dispersion of the balances arises from the variation of the conditions at the contact surface. This variation arises from the roughness of the contact surface, and, by the plastic deformation of this microscopic roughness at the contact surface, the roughness changes at each time of the contact. This cause of the dispersion is the specific character of the knife edge, so this failure cannot be avoided by controlling the circumferential conditions as long as this mechanism is used. But if the beams and weights to be measured were hung with the elastic fulcrum instead of the knife edge, this cause may be vanished. The sensitivity of the balance having the elastic fulcrum is given, and it is revealed that the dispersion in this case is very little as compared with the dispersion in the case of knife edge.

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On the Roller Straightener : 2nd Report, Straightening of Round Bars, Pipe and Tubings

Haruo TOKUNAGA

1960 Volume 26 Issue 172 Pages 1720-1726
Published: December 25, 1960
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.26.1720

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The rotary straighteners straightening round bar and tubes are discussed. The auther derived that the residual stress distribution in the bar straightened by the rotary straightener is such as a vortex alternate of tensile and compressive stress zones around the centre of the bar, which are not effected by the repeated rotary bending. To obtain the better straightness, therefore, the bar has to be bent more severely at point under the rolls, and receive more multiple rotary bending on the bar near the outlet in the straightener. For the rotary plastic bending of the bar, the direction of the bending moment is not coincide with that of the bending of the bar, and these is some angle between both directions, and therefore the power consume to the rotary plastic bending of the bar. In this point of view, the auther derived a formula to culculate the power required for straightening of the bar. The residual stress in the seamless tube straightened by a seven-roll rotary straightener is measured by the cutting removed method using an electrical resistance straingauge, and the auther shows a convenient culculating process for the above mentioned measuring method.

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The Mechanism of Lubrication of Tapered Roller Bearing at High Speed

Tokio SASAKI, Norio OKINO

1960 Volume 26 Issue 172 Pages 1726-1734
Published: December 25, 1960
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.26.1726

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As the friction of rolling bearing is composed of the frictions at contact surfaces between rolling elements, raceways and retainer, each one of them should be investigated under respective operating conditions. In this paper, the mechanism of bearing friction of tapered roller bearing at high speed is analyzed theoretically by comparing with experiments. As a result, the fundamental factors composing bearing friction are divided into two parts ; (1) The friction to which the rolling friction at the contact surfaces between rollers and raceways is attributed. (2) The friction to which the sliding friction between rollers and retainer or shoulder of inner race is attributed. At low speed including starting, the latter factor is the main part of the friction. But, at high speed, the bearing friction mostly consists of former factor and it is almost fluid friction of oil film between rollers and raceways, so that the friction of tapered roller bearing at high speed may be approximately expressed with hydrodynamic theory of friction.

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Research on Metal Cutting Force

Yoshio KITAMIKADO

1960 Volume 26 Issue 172 Pages 1735-1740
Published: December 25, 1960
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.26.1735

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In the case metal cutting, the resisting force against the deformation of workmaterial is a very important problem. Therefore, many investigators have dealt with this problem. But, then, the workmaterial was assumed as a perfect ideal plastic, and if not, only metal property of static state was considered. In order to find the theoretical relation between the cutting force and the strength of workmaterial, we think we must take the dynamic property of workmaterial into consideration. So, we made an experiment on shear strees-strain relation at various strain rate. Basing on this, we found theoretical relation between the cutting force and the strength of material. Moreover, to make sure of it, we made cutting experiments on the same material (solder) which had been used in the shear stress-strain test. This study has definitely showed that the dynamic property of workmaterial has a great effect on the cutting force.

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On the Vibration of Milling Machines

Shizuo DOI, Hazime KURITA

1960 Volume 26 Issue 172 Pages 1740-1748
Published: December 25, 1960
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.26.1740

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The chatter vibration that occurs in machining operation is magnified by microscope and measured on the rotating film. The forced vibration which is caused by the unbalance of the driving motor and the operation of the cutter teeth is experimented. When the width of cut, the feed or the cutting speed is increased, the self-excited vibration, that is chatter, occurs frequently due to the deflection of the cutter arbor and the overarm. The ordinary chatter is commonly of the self-excited vibration. The character or this vibration is ascertained. Experiment is carried out on the relation between the occurrence of the chatter and the supporting method of the cutter arbor.

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Method for Measuring Curved Surfaces by a Series of Curves or Straight Lines

Koyu MIYAZAKI

1960 Volume 26 Issue 172 Pages 1749-1759
Published: December 25, 1960
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikai1938.26.1749

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For testing curved surfaces, the author draws many curves on these surfaces, and regarding these curves as a series of curves or straight lines, he measures relative errors of these surfaces compared with the standard ones by using a simple instrument with one or more indicators. In the present paper, he gives both theory and experimental results of method based on the above principle, and examines whether it is to be practically applicable.

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