Showing papers in "Jsme International Journal Series B-fluids and Thermal Engineering in 1961"
TL;DR: In this article, the resistance of a water flow through co-axial cylinders when the inner cylinder rotates, is studied experimentally, and the resistances are measured for six gap sizes (s/r1=0.0136∼0.115, s : gap, r1 : radius of inner cylinder) and for various combinations of axial and rotational flows.
Abstract: In this paper, the resistance of a water flow through co-axial cylinders when the inner cylinder rotates, is studied experimentally. The resistances are measured for six gap sizes (s/r1=0.0136∼0.115, s : gap, r1 : radius of inner cylinder) and for various combinations of axial and rotational flows. Results obtained are as follows : 1. When the axial flow is laminar, the resistance of a flow is unaffected up to a certain rotating speed (Rωc : critical rotating Reynolds number), but beyond this speed the flow resistance increases as the Rω increases. 2. The value of critical Taylor number Rωc(s/r1)1/2 increases as the axial Reynolds number (Re=vms/ν) increases up to a certain value (Re=600), beyond this value Rωc(s/r1)1/2 decreases to zero with the increase of Re. When the axial flow is turbulent, such a critical rotating Reynolds number cannot be recognized. 3. When Rω>10 000, the resistance coefficient of a flow λ can be expressed by λ= 0.26 Re-0.24 ×{1+(7/8)2(Rω/2Re)2}0.38 even for small Re.
136 citations
TL;DR: In this paper, a simple method for finding the optimum shape of a chip-breaker was established by measuring the thickness of chip which is obtained under the given cutting conditions and by the use of a diagram presented in this paper.
Abstract: Limiting condition of chip breaking with a parallel type chip-breaker has been found to be determined by only the follwing three items : the radius of chip flow circle, the material to be cut and the thickness of chip. The larger the radius of chip flow circle, the steeper the slant of a chip-breaker and the thinner the chip, the smaller was the force acting on a chip-breaker due to chip curling. The yield stress of chip was found to become about twice that of the same material before cut. From these results, a simple method for finding the optimum shape of a chip-breaker was established. In this method, a proper radius of chip flow circle is found directly by measuring the thickness of chip which is obtained under the given cutting conditions and by the use of a diagram presented in this paper.
68 citations
TL;DR: In this paper, a theoretical quantitative study of gas leakage through the piston-rings of an internal combustion engine is presented, showing that the discharge coefficient is 0.8∼0.9 and its mean value is about 0.86 when the states of leakage gas are near to those of an actual working engine.
Abstract: The following terms are necessary for a theoretical quantitative study of gas leakage through the piston-rings of internal combustion engine : (1) the discharge coefficient through the narrowest gas passage, (2) the temperature of gas in the space between two rings. So at first the former is measured by letting a high temperature compressed air flow out through a gap of piston-ring set in the experimental apparatus. Next, the latter is studied using the apparatus provided with a stationary piston and a reciprocating cylinder. As a result, the following conclusions are obtained : (a) the discharge coefficients are 0.8∼0.9 and its mean value is about 0.86 when the states of leakage gas are near to those of an actual working engine, (b) the temperature of gas flowing out around the piston-rings almost is equal to that of gas on the surface of piston.
46 citations
TL;DR: In this article, the appearance of variation and absolute value of the thickness of oil film measured against the phase of a stroke and a μU/W which is determined by the running condition coincide approximately with the result of theoretical calculation.
Abstract: Some experimental studies are made on the oil film thickness of the piston-ring which was obtained theoretically in the 1 st Report. The same apparatus as in the 2 nd Report is used, and the 1 st method of this work is a measurement of the electric resistance between the cylinder and whole body of the piston-ring or its certain local parts, and the 2 nd method is a measurement of the circumferential displacement of the gap of ring. From these experiments, it is shown that the appearance of variation and the absolute value of the thickness of oil film measured against the phase of a stroke and a μU/W which is determined by the running condition coincide approximately with the result of theoretical calculation.
40 citations
TL;DR: In this article, the authors used the measuring values of the discharge coefficient and the temperature of a gas flowing through the piston-rings to calculate the amount of leakage gas and its pressure distribution.
Abstract: The measuring values of the discharge coefficient and the temperature of a gas flowing through the piston-rings which were obtained in 1 st Report, are used to calculate the amount of the leakage gas and its pressure distribution under several conditions of the piston-rings. And comparing these calculated results with the previous experimental ones, the following conclusions are reached ; (1) The calculation and experimental values are consistent in results, (2) the mechanism of gas leakage through the piston-rings corresponds to that of a gas flowing through the labyrinth, changing rapidly its properties, (3) especially, the unsteadiness of leakage flow produces an interesting effect upon the gastightness, (4) and it is also proved that the leaking gas hard y contains combustion gas when estimated from the theoretical calculation.
35 citations
TL;DR: In this paper, the mechanism of prevention of wrinkling in deep drawing operations was clarified and formulas were induced theoretically to predict the critical conditions of wrinkles in both cases when a blank-holder is not used and where a blankholder is used.
Abstract: In this work, examining actual phenomena of wrinkling in deep drawing operations, the mechanism of prevention of wrinkling are clarified. In addition, formulas are induced theoretically to predict the critical conditions of wrinkling in both cases where a blank-holder is not used and where a blank-holder is used. As the first report, fundamentals of analytical method and results in case where a blankholder is not used are reported.
23 citations
TL;DR: In this article, a high speed gear testing machine at a periphery velocity of 80 m/sec and below was used to measure the dynamic load on spur gear teeth. But the results showed that the dynamic loads of the ground gears were nearly equal to the ones tested as a driver.
Abstract: Dynamic loads on spur gear teeth are measured by a high speed gear testing machine at a periphery velocity of 80 m/sec and below. The ground gears (some of them have pressure angleerrors) are tested as reduction gears and also as speed-up gears respectively. The maximum dynamic loads occur at a critical speed, at which the meshing frequency is equal to the natural frequency of the vibratory system consisting of a pinion, a gear and a combined tooth stiffness. At a speed over the critical one, the magnitude of the dynamic load approaches a certain constant which is determined by the tooth errors. When the errors are repeated in each meshing as in these cases, the dynamic loads of the gear tested as a follower are nearly equal to the ones tested as a driver.
23 citations
TL;DR: In this article, a method promoting a fluid lubrication in the deep drawing of sheet metals is introduced, which is proved by laboratory scale experiments on aluminium and reported that the process brought about many encouraging results for the improvement of the drawing ratio.
Abstract: In this paper, a method promoting a fluid lubrication in the deep drawing of sheet metals is introduced. Possibilities of this method are proved by laboratory scale experiments on aluminium and reported. It is shown that the process brought about many encouraging results for the improvement of the drawing ratio. Some contributions are made to the practical developement of this process by clarifying fully the pressure characteristic of this method which is an important key to its success.
20 citations
TL;DR: In this article, the authors used the two-dimensional elastic theory and the transform function to calculate the bending stress of a gear tooth theoretically and finding the bending strength of a spur gear.
Abstract: The present study was carried out for the purpose of calculating the bending stress of a gear tooth theoretically and finding the bending strength of a spur gear. Using the two-dimensional elastic theory and the transform function, the authors introduced equations for the calculation of the stress at the fillet curve of a gear tooth. Investigating the stress calculated by these equations in various loading conditions, the authors reached the conclusion that it was reasonable to take the shearing force into consideration for the calculation of the bending stress of a gear tooth. Then they introduced equations for the calculation of the inner stress, and obtained the following result : the inner stress shows a smaller value than the stress at the fillet curve, so it is reasonable to determine the bending strength of a gear tooth by calculating the maximum stress at the fillet curve.
14 citations
TL;DR: In this paper, the ground pinion and gear were tested at the perithery velocity 80 m/sec and below at the critical speed at which the meshing frequency is equal to the natural frequency of the vibratory system consisting of the pinion, the gear and the combined tooth stiffness.
Abstract: Dynamic loads on spur gear teeth are examined by a gear testing machine and a strain gauge apparatus. The ground pinion and gear are tested at the perithery velocity 80 m/sec and below. Some teeth of the gear have normal pitch errors of about 15μ which are given on purpose. The magnitude of the dynamic load increases at the critical speed at which the meshing frequency is equal to the natural frequency of the vibratory system consisting of the pinion, the gear and the combined tooth stiffness. At a speed over the critical one, a heavy dynamic load occurs on the tooth which has a protruded error. If there is a tooth which has an indented error, the tooth tends to carry no load, and a heavy dynamic load will occur after several teeth. The calculated results, which are analysed as a vibration problem, are nearly coincident with the measured results.
12 citations
TL;DR: In this paper, the half-value breadth of the X-ray diffraction lines taken from (310) atomic plane with C0-Kα radiation, which were obtained from the specimens of carbon steel wire, cast iron and cast steel stressed alternately in rotary bending, was studied.
Abstract: In the present paper, the fatigue process is studied by observing the half-value breadth of the X-ray diffraction lines taken from (310) atomic plane with C0-Kα radiation, which were obtained from the specimens of carbon steel wire, cast iron and cast steel stressed alternately in rotary bending. It is found that during the fatigue process the change of half-value breadth is directly related with the change in micro-stresses. Considering from the change of half-value breadth due to stress cycles, the authors think that the fatigue process consists of three sequent stages, namely the first stage of fatigue, secondary stage of fatigue, and tertiary stage of fatigue. At the end of the secondary stage of fatigue the half-value breadth has a constant value irrespective of the magnitude of applied stress. The relation between b/B and log n/N (b and B are the current and the initial value of half-value breadth, and n and N are the current and the ultimate number of stress cycles) is represented by a straight line irrespective of the magnitude of alternate applied stress. This relation supplies a possibility for the non-destructive prediction of the fatigue life.
TL;DR: In this paper, the cause of the thermal crack in the carbide face-milling cutter has been investigated from the view of thermal shock accompanying the intermittent cutting and the influence of cutting conditions on the thermal cracks has been examined.
Abstract: Fundamental characteristics and cause of the thermal crack which appears in the carbide face-milling cutter have been investigated. The observation of a thermal crack has revealed a lot of interesting features of the initiation and growth of the thermal crack. The cause of a thermal crack of the carbide face-milling cutter has been considered from the view-point that, as generally said, it is due to the thermal shock accompanying the intermittent cutting. Next, the influence of cutting conditions on the thermal crack has been investigated and sometimes found explainable by the above consideration. At last, several grades of carbide have been examined experimentally in respect to the occurrence of the thermal crack.
TL;DR: In this article, the compression of a wedge by a rigid flat die when the initial condition is symmetrical has been investigated, and the complete solutions have been obtained for seven modes of deformation.
Abstract: In this report, the compression of a wedge by a rigid flat die when the initial condition is symmetrical has been investigated. Ten modes of deformation of the wedge are expected depending on the friction at the die surface and the thickness of the wedge but the complete solutions have been obtained for seven modes of them. Some considerations have been made on the extremum principle taking into account the energy dissipation at the frictional surface and applied to the kinematically admissible field to estimate the load in the modes for which the complete solution is unknown as yet. It seems that the kinematically admissible field which satisfies the stress boundary condition on the frictional surface gives an estimation of the load nearly the same as that of the exact solution. It has been shown that the method to estimate a mean value of strain from the work of deformation is convenient.
TL;DR: In this paper, the authors presented an experimental investigation about the spline shaft by the threedimensional photoelastic method, and it was shown that the maximum bending stress of the tooth was comparable with the maximum torsional stress.
Abstract: This paper presents an experimental investigation about the spline shaft by the threedimensional photoelastic method. The results are as follows : (1) The stress distribution of the spline shaft was measured by Dr. Nisida's wedge method, and the stress concentration factor was obtained. The results were coincident fairly well with those of other methods. (2) The accuracy of the wedge method was checked and its value was about 5%. (3) The stress distribution of the meshing spline shaft was investigated, and it was shown that the maximum bending stress of the tooth was comparable with the maximum torsional stress.
Journal Article•
TL;DR: In this paper, the free vibration of a one-degree-of-freedom system with an elastically supported viscous damper and with arbitrary stiffness ratio k of the springs is considered.
Abstract: In this paper, the free vibration of a one-degree-of-freedom system with an elastically supported viscous damper and with arbitrary stiffness ratio k of the springs is considered. The interesting facts that the system has an optimum damping value for the free vibration and that the value is nearly equal to that for the displacement of forced vibration, have been derived from the study. In addition, the transient vibration of a vehicle equipped with a damper adjusted adequately for the steady motion in passing over a raised or sunken place, has been investigated, comparing the result with that of a vehicle with the conventional type of suspension consisting of a spring connected in parallel with a damper, and it has become clear that the former has considerable advantages over the latter in softening shocks.
TL;DR: In this article, the authors measured the noise of three kinds of the fitted ball bearings, analyzed the peak frequency in the frequency spectrums, and obtained the results as follows: (1) The noise of a fitted ball bearing has the frequencies above 1 kc/sec.
Abstract: Noise of ball bearing can be divided into two cases ; one is the case of a simple ball bearing, the other is the case of a fitted one. The noise of the latter case has not been researched systematically. The author measured the noise of three kinds of the fitted ball bearings, analyzed the peak frequency in the frequency spectrums, and obtained the results as follows : (1) The noise of a fitted ball bearing has the frequencies above 1 kc/sec. The frequencies of the noise do not change at many shaft speeds, but the sound pressure level increases with the shaft speed. (2) The principal noises of a fitted ball bearing are due to the vibrations on the race rings, and the other noises are due to the vibrations on the cage. (3) The fitted ball bearing noise and the simple one are identical in essence.
TL;DR: In this article, the extrudate swelling (Barus'effect) and extrudiate irregularities are qualitatively explained and the drag of a sphere placed in the viscoelastic fluid flow is calculated roughly, assuming that the elastic energy is stored in the flowing fluid.
Abstract: Bagley and others showed that the additional loss at the entry of a capillary tube, through which a viscoelastic fluid flows, was a strong function of the apparent shear rate However, no one has ever attempted to treat analytically the entrance additional loss, as far as the author's knowledge is concerned In this paper, assuming that the elastic energy is stored in the flowing fluid, this problem is approximately analysed Then, the extrudate swelling (Barus'effect) and the extrudate irregularities are qualitatively explained Moreover, the drag of a sphere placed in the viscoelastic fluid flow is calculated roughly
TL;DR: In this paper, a theory for the calculation of unsteady laminar boundary layers in an incompressible fluid about a two-dimensional body is presented, where velocity fluctuation in the boundary layer is also expressed as a power series of x, whose coefficients are functions of the non-dimensional distance measured normal to the surface.
Abstract: A theory is presented for the calculation of unsteady laminar boundary layers in an incompressible fluid about a two-dimensional body. Fluid velocity in the main stream just outside the boundary layer, expressed as a power series of the distance x measured along the body surface, is assumed to fluctuate about its mean value. The magnitude and frequency of the fluctuation are assumed to be small. Velocity fluctuation in the boundary layer is also expressed as a power series of x, whose coefficients are functions of the non-dimensional distance measured normal to the surface. These coefficient functions are universal and can be tabulated once and for all. Functions corresponding to the main stream velocities of third order polynomial and frequencies up to second order are actually computed and tabulated. As an example, the movement of the boundary layer separation point on a circular cylinder is calculated. The movement, although it increases with frequency, is rather small.
TL;DR: In this paper, the authors investigated the scavenging process in a model cylinder having a cross-scavenging system and the movement of the scavenge front in the cylinder and the short-circuiting of fresh charge were investigated by an electronic method.
Abstract: This paper reports the results of an investigation on the scavenging process in a model cylinder having a cross-scavenging system. The movement of the scavenge front in the cylinder and the short-circuiting of fresh charge were investigated by an electronic method. The profile of the scavenge front was made clear. The port arrangement investigated here gives a flat scavenge and an early short-circuiting occurs at the exhaust ports located near the scavenging ports. A poorly scavenging region exists above the exhaust ports.
TL;DR: In this paper, the authors describe some experiments with roller testing apparatus with which the frictional moment and the electrical resistance between the rollers were measured under various driving conditions of contact load P, rolling speed Vr, specific sliding S, oil viscosity η, relative radius of curvature ρ and roughness of contact surface Hmax.
Abstract: For the purpose of finding radical preventive measures for the wear and damage of the geartooth surface, the present study was carried out. This paper describes some experiments with roller testing apparatus with which the frictional moment and the electrical resistance between the rollers were measured under various driving conditions of contact load P, rolling speed Vr, specific sliding S, oil viscosity η, relative radius of curvature ρ and roughness of contact surface Hmax. Depending upon the dimensionless parameter ηVr/P, the lubricating characteristics can be classified into three regions. And the empirical formula of the frictional coefficient in the region of semi-fluid lubrication is induced. The friction obtained under a sliding motion with rolling is very much larger than that under a pure rolling, and the maximum frictional coefficient is found for a comparatively small specific sliding. The relative radius of curvature and the roughness of contact surface have much influence upon the oil-film thickness.
TL;DR: In this article, the position of the weakest section of a gear tooth and the stress concentration factor at the tensile-side fillet of a tooth were studied, and the relation among these factors was found.
Abstract: In the present paper the authors studied the position of the weakest section of a gear tooth and the stress concentration factor at the tensile-side fillet of a tooth. Then they calculated the stress concentration factors for some components of the force on the tooth profile, and found the relation among these factors. Consequently the following formula has been introduced for the bending stress of a gear tooth : σ =(1+0.08S/P) (0.66σNb+0.40√(σ +36τN2>+1.15σNc) By this formula the authors calculated the bending stress of gear teeth of some shapes, and compared the results with those of photo-elastic experiments.
TL;DR: In this paper, the two valves installed on the cylinder head are to be timely opened by the overhead cam shaft driven at half an engine speed, and to extract the gases of the same cycle before and after the scavenging, giving the possibility of determining either the engine is operated as fourstroke cycle, or the trapping efficiency when done as two-stroke cycle.
Abstract: The paper deals with a new method of measuring the scavenging efficiency in a loop-scavenged two-stroke cycle diesel engine and its assessment on a test engine. The two valves installed on the cylinder head are to be timely opened by the overhead cam shaft driven at half an engine speed, and to extract the gases of the same cycle before and after the scavenging, giving the possibility of determining either the scavenging efficiency when the engine is operated as fourstroke cycle, or the trapping efficiency when done as two-stroke cycle. The experments employing this apparatus revealed a great deal of valuable information for improving the scavenging system, and also indicated that the scavenging efficiency in a well-designed cylinder could reach over 90% at a delivery ratio of 1.3∼1.4, which does not seem to be inferior to that obtained in the uniflow scavenged system.
Journal Article•
TL;DR: In this paper, the axial motion of a horizontal rotor supported by a ball bearing and a journal bearing was analyzed and the results showed that the ball bearing possesses a spring constant varying with the motion of the balls.
Abstract: The authors analyzed the axial motion of a horizontal rotor supported by a ball bearing and a journal bearing. The results of analysis show that the ball bearing possesses a spring constant varying with the motion of the balls. So in some regions the motion becomes unstable and a subharmonic vibration of the order one-half may appear. Statical experiments in order to determine the stiffness of the ball bearing and dynamical experiments to measure the subharmonic vibrations of the order one-half have been carried out for two ball bearings having respectively three and six balls. The unstable regions where a subharmonic vibration appeared agreed with the analytical results. At the boundaries between the stable and the unstable regions, the subharmonic vibration and the forced vibration caused by the inclination of the groove of the inner ring composed a beat. The period and the phase of the beat agreed with the analytical results.
TL;DR: For the purpose of calculating the bending strength of the gear tooth in general use, the position of the weakest section of a gear tooth and the point of the worst loading were considered in this article.
Abstract: For the purpose of calculating the bending strength of the gear tooth in general use, the authors studied theoretically the position of the weakest section of a gear tooth and the point of the worst loading, and consequently defined the calculating method of nominal stress. Then by using the calculating equation of bending stress and stress concentration factor of gear teeth of various shapes in general use at present, they studied these relations.
TL;DR: In this paper, a method of calculating the fluctuating boundary layer on a circular cylinder, performing rotational oscillation in a uniform flow, is presented, based on the asymptotic behavior, at a large distance from the solid wall, of the streamlines.
Abstract: A method of calculating the fluctuating boundary layer on a circular cylinder, performing rotational oscillation in a uniform flow, is presented. Two-dimensional, laminar flow of an incompressible fluid is assumed. Equation of motion is linearized on the assumption that the velocity fluctuation in the boundary layer is small. The frequency of the fluctuation is also assumed rather low, thus retaining terms up to the first order in frequency. By extending the Blasius'series method to unsteady flow, solutions are expressed as linear combinations of a family of universal functions. As an example, the torque fluctuation of the cylinder is calculated. Streamline patterns near the separation point of the boundary layer are calculated, by observation of which a new criterion of the separation of the unsteady boundary layer is proposed. It is based on the asymptotic behavior, at a large distance from the solid wall, of the streamlines.
TL;DR: In this paper, the problem of laminar free convection accompanied by vapor transfer on a flat plate placed vertically in humid air is treated on some assumptions, by means of the successive method, the equations of motion, energy and diffusion are solved.
Abstract: The problem of laminar free convection, which is accompanied by vapor transfer, on a flat plate placed vertically in humid air is treated on some assumptions. By means of the successive method, the equations of motion, energy and diffusion are solved. As practical examples, calculation is carried out under the conditions where the Prandtl number is a constant, 0.72, and the Schmidt number takes three respective values, 0.5, 0.6 and 0.72. Both θ'(0) and M'(0) are approximately proportional to [numerical formula]. Where θ'(0) and M'(0) are gradients of temperature and partia1 density of vapor at the wall, respectively, Cw the density of humid air at the wall, Cvs, Cvw the partial densities of vapor at an infinite distance and at the wall, respectively.
TL;DR: In this paper, the theory of pseudo-steady plastic flow was applied to analyze the metal cutting mechanism in the transitional cutting stage after first contact between the cutting tool and the work material.
Abstract: To analyze the metal cutting mechanism in the transitional cutting stage after first contact between the cutting tool and the work material, the theory of pseudo-steady plastic flow was applied. Determining the relation between friction angle on tool face and cutting time by cutting test, the change of cutting mechanism during the transitional stage was analyzed theoretically. This was compared with the experimental result on lead. It was found that both theoretical and experimental results followed a similar trend.