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Article type: Cover
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Published: August 05, 2003
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Article type: Appendix
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App1-
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Article type: Index
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Published: August 05, 2003
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Hideo TAKAHASHI, Hiroshi IIZUKA
Article type: Article
Pages
1-2
Published: August 05, 2003
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Fatigue failure mechanism in synchronous belts with steel cord was investigated. The belt failure was initiated near the tooth root, where the steel cords were broken. The steel cord was made for twisting nineteen steel wires. It consisted of one core wire, six inner layer wires and nine outer layer wires. The bending fatigue tests of the steel cord were carried out and discussed the fatigue failure mechanism. The bending fatigue was firstly initiated for the outer wires. However, the bending stress was highest in the center core wire according to our geometrical analysis. Therefore, the interaction between the wires may increase the axial stress and the total stress of the bending and the axial stresses may fatigue the outer wire. On the other hand, the FEM results showed that the maximum stress occurs in the outer layer wire by the restriction between wires.
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Motoyuki SAKURAI, Hiroshi IIZUKA
Article type: Article
Pages
3-4
Published: August 05, 2003
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Synchronous-belt used for the camshaft drive in automobile engine is driven under fluctuation torque conditions. In this study, the belt deformation, namely belt curvature and shearing strain, is measured under the fluctuation torque condition. Especially, the effect of pitch difference between belt and pulley on the belt deformation is discussed. The belt deformation is small for the short pitch belts.
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Hiroshi Iizuka, Yoshikatsu Ohta, Akihiro Ueno, Takeshi Murakami
Article type: Article
Pages
5-6
Published: August 05, 2003
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Fatigue failure under fluctuating torque is important because the driving torque fluctuates in automotive engine camshaft drive-systems. The authors observed that the fatigue failure initiated at the tooth root on the opposite side of working flank under fluctuating torque conditions, while the failure initiated at the tooth root on the working flank side under constant torque conditions. In this study, the main factor that decides the failure initiation site is discussed, caring out some experiments and finite element analysis (FEA). According to the FEA results, the maximum stress initiation site is moved from the opposite side of working flank to the working flank side, increasing with the tooth load. The main factor that decides the failure initiation site is the distribution of tooth load on the working flank.
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Naoya KITAMOTO, Masanori KAGOTANI, Hiroyuki UEDA, Tomio KOYAMA
Article type: Article
Pages
7-8
Published: August 05, 2003
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Helical synchronous belt drives are more effective than conventional synchronous belt drives with respect to reducing noise and transmission error per single pitch of the pulley. However, the helix angle of the tooth trace causes axial belt movement. Therefore, a flanged pulley is used in a helical synchronous belt drive. In the present study, the transmission error in a helical synchronous belt drive using a flanged pulley under installation tension was investigated both theoretically and experimentally for the case where the pulley was rotated in bidirectional operation. The computed transmission error agrees well with the experimental results, thereby confirming the applicability of the proposed theoretical analysis for transmission error. In this case, transmission error is found to be generated by the difference in axial belt movement between the driving and driven sides. The transmission error does not occur when the pulley alignment error between the driving and driven pulleys is set to zero.
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Hiroyuki UEDA, Masanori KAGOTANI, Tomio KOYAMA
Article type: Article
Pages
9-10
Published: August 05, 2003
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Helical synchronous belt is used in order to reduce noise and transmission error. However side tracking in helical synchronous belt is more problematic than that in conventional drives. In the present study, method for reducing side tracking in helical synchronous belt by adjusting outside diameter of the pulley under torque was investigated both theoretically and experimentally. As a result, side tracking can be reduced when outside diameter on the driving pulley is larger than that on the driven pulley. It can be adjusted outside diameter of the pulley so as not to cause side tracking.
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Yoshiaki KATO, Yoshihiro KONO
Article type: Article
Pages
11-12
Published: August 05, 2003
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The dynamic behavior of a metal CVT belt was calculated under the conditions of the lowest pulley ratio of a 2-liter class unit and high input torque by using 3-D finite element analysis (FEA) simulations. The calculated results were then used to analyze the torque-transmitting mechanism of the metal CVT belt. As a result, it was found that 62% of the input torque was transmitted by the compressive force of the elements and 32% by the tensile force of the bands. It was also revealed that the slip velocity between the primary pulley and the elements contributing to the compressive force between the elements was in a range of 500-1,000mm/s in the angle of contact on the primary pulley.
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Kazuteru NAGAMURA, Kiyotaka IKEJO, Koki TAKEDA
Article type: Article
Pages
13-14
Published: August 05, 2003
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We carried out a pitting test and a scoring test lubricating with three biodegradable oils, a mineral hydraulic oil and a turbine oil, and measured the surface temperature on the gear tooth by a dynamic thermocouple to investigate the effect of the biodegradable oil on he surface failure of spur gear. It were found that the pitting resistances of biodegradable oils are higher than that of a mineral hydraulic oil and lower than that of a turbine oil, and that biodegradable oils have higher scoring resistances than a mineral hydraulic oil and a turbine oil.
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Ryohei ISHIMARU, Yasutsune ARIURA, Yoji MASTUKAWA, Masahito GOKA
Article type: Article
Pages
15-16
Published: August 05, 2003
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Austempered Ductile Iron (ADI), which has much the same strength and toughness as usual steels, have been developed. ADI has many advantages in mechanical properties and manufacturing, such as weight reduction, good properties of vibration and noise, low cost in machining and heat treatment of blanks due to near-net-shape casting. Using these advantages, it has been reported that ADI can be sufficiently applied as a medium hardness gear material. In addition, it is important to reduce the use of the lubricating oil when many problems, i. e. global environment, resource conservation and cost reduction, etc., are considered. So it is necessary to examine the performance of ADI under oil-free condition of Minimal Quantity Lubrication (MQL) condition. In this paper, the surface durability of ADI rollers is investigated using a disk machine which simulates the rolling and sliding action of gears. In particular, the surface durability under the MQL conditions is examined in comparison with the steel which has almost the same hardness of ADI.
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Kunihiko MORIKAWA, Ryuuta NISHIHARA, Mikio NAGAHARA, Yasuo TOMITA
Article type: Article
Pages
17-18
Published: August 05, 2003
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Most transmissions that use a traction drive mechanism also have a gear train to transmit power to the outside. In these transmissions, traction oil is used both as the working fluid and gear lubricant. Since precedence is given to the performance of traction oil as a working fluid, its performance as a lubricant is generally inferior. The traction coefficient of traction oil is higher than that of automatic transmission fluids (ATFs), so it is thought that the power loss of meshing gears under traction oil will be larger than that under ATF. In this paper, we experimentally compare the power loss of meshing gears between use with traction oil and with ATF and show that the power loss with the former increases by approximately 0.5% compared with that found for ATF. It is shown that the magnitude of the power loss depends on the gear dimensions and operating conditions.
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Akira YOSHIDA, Masanori SEKI, Yuji OHUE, Yoshikazu GOTODA, Daisuke HAY ...
Article type: Article
Pages
19-20
Published: August 05, 2003
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The purpose of this study is to investigate the influence of shot peening on the pitting strength of case-hardened steel rollers. The hardness, the compressive residual stress and the surface roughness of the rollers increased by the shot peening. The failure mode of the rollers was pitting. The surface durabilities of most shot-peened rollers were higher than that of the unpeened roller in these experiments. Especially, the smaller the surface roughness of the shot-peened rollers was, the higher the surface durabilities of them were. The increase of the surface roughness by the stronger shot peening resulted in the shorter fatigue lives of the shot-peened rollers. Therefore, it could follows from this that the light shot peening should be selected in order to improve the pitting strength of the steel rollers in these experimental range.
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Takao KOIDE, Koji TSUBOKURA, Masayuki NAKATANI, Kouitsu MIYACHIKA, Sat ...
Article type: Article
Pages
21-22
Published: August 05, 2003
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This paper describes a study on the surface durability of plasma-carburized rollers. Test rollers of MAC14 and SCM415 steels were plasma-carburized under different carburizing conditions. The contact fatigue tests were carried out for these test rollers. The effects of case depths on the contact fatigue strength of rollers were determined. The effect of shot-peening on the contact fatigue strength was also examined by carrying out contact fatigue tests for shot-peened rollers. The results were compared with the results for super- or eutectoid-carburized rollers. The contact fatigue strengths of plasma-carburized rollers become larger with an increase of case depth and are larger than those of super- or eutectoid-carburized rollers. The surface failure modes of plasma-carburized rollers were spalling. The load bearing capacity of plasma-carburized rollers was found to become larger by shot-peening.
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Jun WATANABE, Toshikazu OSHIDARI, Kiyofumi YOSHITANI
Article type: Article
Pages
23-24
Published: August 05, 2003
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It is essential to ascertain traction characteristics under actual operating conditions in order to apply a toroidal CVT incorporating a traction drive system to automobiles. This paper first describes the traction characteristics obtained quantitatively over a wide range of conditions by using an actual variator. The resulting characteristics showed the large influence of spin. Furthermore, an attempt was made to obtain the calculated prediction of an actual variator by using a viscoelastic-plastic model with a measured temperature of variator. A comparison was made between the calculated results and the actual variator test results. It was found that an accurate prediction of traction characteristics requires the surface temperature of variator.
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Ichiro MORIWAKI, Koji WATANABE, Toshiro MIYATA
Article type: Article
Pages
25-26
Published: August 05, 2003
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Although contact stress is one of the most important factors for gear design, the contact stress between tooth flanks of gears has not been measured experimentally. The present paper describes experimental measurement of contact stress between tooth flanks of spur gears which are subject to a static load. For this purpose, designed and manufactured was a new experimental apparatus which enables various misalignments and a static load to be given to spur gear pair. In order to measure contact stress, a pressure measurement film was used. The film enables contact stress between tooth flanks of gears to be measured.
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Ryohei ISHIMARU, Yasutsune ARIURA, Kotaro HIDAKA, Masahito GOKA
Article type: Article
Pages
27-28
Published: August 05, 2003
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Austempered Ductile Iron (ADI), which has much the same strength and toughness as usual steels, have been developed. ADI has many advantages in mechanical properties and manufacturing, of example, weight reduction due to smaller density than that of steel, good properties of vibration and noise, low cost in machining and heat treatment of blanks due to near-net-shape casting. It has been reported that ADI can be sufficiently applied as a medium hardness gear material. In medium hardness gears, tooth surface failure of steel gear is usually pitting, which occurs in all teeth and gradually progresses. However, in the case of ADI gear that is medium hardness, tooth surface failure is spalling, which occurs suddenly on a few teeth. On the spalling of ADI gear, the situation of generation and progress of the crack has not been clarified well. In this paper, the damages occurred on ADI gear tooth were observed in detail, and the mechanism in which spalling is occurred is investigated.
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Tomoya MASUYAMA, Katsumi INOUE, Hideaki KASAI
Article type: Article
Pages
29-30
Published: August 05, 2003
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Focusing on the hardness, residual stress and inclusions, a simulation method was proposed to compute the fatigue strength of carburized gears. The simulation is based on the comparison of bending stress at every position of defects with material's strength. For the purpose of putting inclusions in the imaginary material for the computation, the distribution of the inclusions size is applied in the weibull distribution, based on the microscope observation. In this study, the influence of the weibull parameter on the fatigue strength distribution is investigated. In order to manufacture the high strength gear, decreasing the weibull parameter η of inclusions distribution in material is useful.
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Kouitsu MIYACHIKA, Hidefumi MADA, Takao KOIDE, Satoshi ODA, Hiroshige ...
Article type: Article
Pages
31-32
Published: August 05, 2003
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An electromagnetic field analysis, a heat conduction analysis and an elastic-plastic stress analysis during the induction hardening process of S35C steel rollers were carried out for various hardening conditions by using FEM program developed by authors, considering changes of the magnetic permeability, the resistivity, the thermal expansion coefficient and the yield stress with the temperature. Effects of the electric power and the frequency on the residual stress and the hardened layer of roller due to the induction hardening were examined. The measurement of hardness distribution of induction hardened rollers was performed, and measured hardened layers were compared with calculated ones.
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Hirofumi SENTOKU, Takahiro SATO, Yoshihide KIYOSAWA, Xin yue ZHANG
Article type: Article
Pages
33-34
Published: August 05, 2003
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Nowadays, Strain Wave Gearing is used in the indirect drive part of an industrial robot and the printing machine, in which high positioning accuracy is necessary. Seeing from the point of the reliability and the durability, the tooth root of the Flexible spline in Strain Wave Gearing is danger. In order to solve this problem, we have to learn the load distribution between the Flexible spline and the Circular spline. However, because the strain gage can not be pasted on the small Strain Wave Gearing, as a replacement, a large-size Strain Wave Gearing is used in this research, and this is proposed as a method for calculating the tooth root stress of any size Flexible spline. In this report, the load distribution on the tooth flank is derived by using the tooth root stress of the Circular spline which is not be influenced by the rim.
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Hiroshi YAMAZAKI, Yoshitaroh YOSHIDA, Yoshihide KIYOSAWA, Satoshi KISH ...
Article type: Article
Pages
35-36
Published: August 05, 2003
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A precise analysis has been made for the designing and manufacturing method of a pinion cutter for non-involute internal gear, especially in the case the profile of the gear is given as a series of dispersive points. Firstly, theoretical equations are derived in order to obtain the profile of the pinion cutter. Secondly, it is clarified that under certain circumstances a singular point (a cusp) will occur on the profile of the pinion cutter, and that, because of the cusp, the interference phenomenon will occur on the profile of the pinion cutter. Thirdly, theoretical equations are derived to obtain the profile of a relief grinding wheel for the pinion cutter. Then, these theoretical equations are verified by practical designing and manufacturing of the pinion cutter.
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Hidenori KOMATSUBARA, Kenichio MITOME, Tatsuya OHMACHI
Article type: Article
Pages
37-38
Published: August 05, 2003
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Conical involute gears used for marine transmission are mostly helical conical involute gears. Besides these gears are not intersecting axis gears but also nonintersecting-nonparallel axis gears. In this case the contact between tooth surfaces of a pair of gears is point contact. Hence the tooth surface durability is generally small. In this research is aimed at the establishment of the design and production system of the Concave conical gears for marine transmissions. In this paper, an allowable normal load of a pair of Nonintersecting-Nonparallel axis concave conical gear is obtained, and a new designing method for these gears is presented. Tooth bearing tests prove that the Heltzian contact ellipse is larger than that of the conventional conical gear. Thus it is proved that this designing method is of practical use.
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Hiroshi GUNBARA, Akira TAKENOSHITA
Article type: Article
Pages
39-40
Published: August 05, 2003
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As a finishing of the gear, the gear honing is often used recently. For extending the life of the grinding wheel, the new honing method (variable shaft angle system) has been proposed. This paper describes the effect of gear ratio between work gear and grinding wheel, and helix angle of grinding wheel on the tool life, when the fixed shaft angle system is adopted. In addition, it is explained that to ease unsymmetrical wear of the dressing gear is possible by appropriately selecting the gear ratio and helix angle, when the variable shaft angle system is adopted.
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Ichiro MORIWAKI, Koji WATANABE, Izuru NISHIWAKI
Article type: Article
Pages
41-42
Published: August 05, 2003
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In the present study, a hypoid design system has been developed. The system will enable tooth bearing, bending stress at tooth root, and contact stress between tooth flanks to be evaluated. As the first step of the study, the present paper describes geometrical analysis of tooth bearing of a hypoid gear pair. The developed program consists of two parts : calculations of generated tooth flank and tooth bearing. In the calculation of generated tooth flank, Formate cutting method is considered for a gear, and The Gleason 116 generator is considered for a pinion. As a result, using practical machine settings, narrow tooth bearing was obtained on the middle of tooth depth.
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Syuhei KUROKAWA, Yasutsune ARIURA, Yoji MATSUKAWA
Article type: Article
Pages
43-44
Published: August 05, 2003
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The influence of gear eccentricity is investigated under no load. Transmission errors including radial eccentricities and cumulative pitch deviations of a pair of spur gear are measured. Several amounts of eccentricity and phase difference of the gear pair are identified by independent measurement. It is clarified that the maximum peak-to-valley values of transmission error curves during whole period of engagement are almost proportional to the sum of the amount or eccentricities in the case of a gear pair, which has the number of teeth relatively prime. In addition, it is essential that cumulative pitch deviations must be included as the components of composite vectors of eccentricity to investigate transmission errors with eccentricities in high accuracy.
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Hidehiro YOSHINO, Fumihiro OHSHIMA, Masaki OHKUBO
Article type: Article
Pages
45-46
Published: August 05, 2003
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It seems more understanding that the tooth surface modification is very important to increase the performance of gear drives. The random pitch errors of the gears may play as a kind of the tooth surface modification. In this paper, the vibration and noise of the super and helical gears with the random pitch errors given intentionally were measured and compared with that of the gears with almost no pitch error. In consequence, it was found that the random pitch error given intentionally has a possibility to reduce the vibration and noise of the gears and widen the range of the frequency.
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Syuhei KUROKAWA, Yasutsune ARIURA, Jun GOTO
Article type: Article
Pages
47-48
Published: August 05, 2003
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Gear transmission errors cause many problems such as efficiency loss, noise, and some kind of failures. If it can be possible to predict gear transmission errors easily, there are many advantages to improve such problems. For helical gears, the amount of transmission errors is usually very small comparing to those of spur gears. One of the reasons is that helical gear pairs have high contact ratios and the total length of line of contact is long. As a result, tooth deflection is small. In this paper, to develop a simulation program for the purpose of estimating gear transmission errors under load, tooth deflections are measured for helical gear pairs, which have different modules and different facewidths. The influence of variation of the length of line of contact on tooth deflection is observed.
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Takeshi WATANABE, Kohei SAIKI, Terushige SATO
Article type: Article
Pages
49-50
Published: August 05, 2003
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Going with interior noise reduction in a vehicle, gear noise that is of pure frequency has been becoming a great influence on the comfortable driving. Therefore, it is necessary to clarify the physical mechanism of each resonance peak by actual measurement. In this research, a helical gearing apparatus is developed to measure the radiated noise and the 3-dimentional vibration of gear pair. As the result, the transverse, axial, rotational, and tilting vibration of helical gear are detected. Especially, some new interesting transverse vibration behaviors, e.g., the drive and driven gears vibrate simultaneously or individually with three different modes, are found.
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Hirofumi SENTOKU, Shinsaku MURATA
Article type: Article
Pages
51-52
Published: August 05, 2003
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Bevel gears are easily influenced by the deflection of gear shafts and bearings. The reason is that both gears shafts cross and one of them is largely cantilever. Those have great influence on the transmission error which is related to the vibration and noise. In the previous report, the transmission error were calculated, when gear shafts were supported by two bearings. However, those transmission error is greatly influenced by tooth profiles. Therefore, in this report, transmission error was calculated, when tooth profiles were spherical Involute tooth type and Gleason tooth type. Effects of tooth profiles on transmission error were clarified with effects of assembly error, torque and crowning.
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Yukitatsu KASHIMURA, Hiroshi OOBAYASHI
Article type: Article
Pages
53-54
Published: August 05, 2003
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Conventional methods such as torque method are mainly used for tightening control. However, it is often difficult to tighten bolt with the required axial force by effect of the friction between both bearing and the thread surfaces. Usually bolts are loosened due to heat, vibration and impact in circumstances. In this study, an axial force sensor using PZT element is proposed. The new developed sensor can estimate the axial force of bolts by measuring the difference of the ultrasonic wave propagation time before and after bolt's tightening. Moreover, a bolt loosing test machine which can control vibration and impact is proposed. In this paper, it is clarified that, the proposed sensor for tightening control is reliable enough to be applied in practical use. Furthermore, the axial force sensor for detecting the loosening of bolt is proved its reliability using bolt loosening test machine.
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Shinji HASHIMURA, Ryousuke IRIE, Isao AOKI
Article type: Article
Pages
55-56
Published: August 05, 2003
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The method to accurately detect the clamping force of bolted joint after tightening has been proposed by the authors. In this study, a new method to easily detect a clamping force due to measuring variation of torque is proposed. In the proposed method, internal threads engage with the bolt threads protruded through the nut at first. Then the bolt threads are pulled by rotating the internal screw. During this process, the upper surface of nut is pressed to the opposite direction and the variation of torque supply to the internal screw is measured. At the moment, when the pulling force reaches the clamping force of the bolted joint, the relationship between torque and displacement at the pulling point varies drastically. The clamping force of a pre-tightened bolted joint was detected experimentally by the proposed method. It is shown that the error of the present method was estimated to be less than about±10%.
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Manabu OKADA, Shinji KASEI, Michihiko TANAKA
Article type: Article
Pages
57-58
Published: August 05, 2003
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Bearing surfaces are important portions for supporting axial tensions of threaded joints. The purposes of this study are to analyze an influence of inclination of bearing surfaces on bending moments acting to bolt shanks by FEM and compare the calculated values with experimented values. The FEM is applied to cases of M10 bolts under initial conditions, which are given as amounts of offsets corresponding to the axial tension and the inclination angle. The result shows that the influence is not less and even the angle around 1° causes a considerably large value of the bending stress in a bolt shank. The result also shows that by a simple formula of the beam theory the influence can be estimated approximately in safety side.
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Masaya HAGIWARA
Article type: Article
Pages
59-60
Published: August 05, 2003
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The revision of ISO 898-1 is now being worked out in ISO/TC 2/SC 1/WG9,in which the introduction of tensile testing method for full-size bolts has been discussed. The tensile testing was originally proposed to check the yield strength and the ductility of the cold forged products (property classes of 4.8,5.8 and 6.8) which cannot be measured by the test using machined test pieces, and the application is going to be expanded to all the property classes for better qualification of the property. The yield strength R_<pf> of full-size bolts is defined as the stress at 0.4% non-proportional elongation, and the permanent elongation at fracture A_f (%) is calculated based on the free thread length set to 1.2d. The aim of this paper is to clarify the relation between the properties on full-size bolts and those obtained from conventional tensile test using machined test pieces, and to propose the appropriate figures on values to be specified. The results from the round robin test conducted by the Japanese ISO/TC 2 Committee show that the test conditions including the type of testing machine affect R_<pf> and A_f values. The load/elongation curves derived from FEM analysis show the feature of those from full-size testing well, and the possibility to determine the detailed testing conditions is confirmed.
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Nobutoshi OHASHI
Article type: Article
Pages
61-62
Published: August 05, 2003
Released on J-STAGE: August 01, 2017
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The hexagon bolts and nuts with flange are used to decrease the pressure on the bearing surface of bolted joints. Generally, tightening of the bolts and nuts with flange is applied to the torque control method. In this report, it was confirmed that the effect of the bearing configurations of the hexagon nuts with flange gave the unstable state to the clamping force by experiment. The result was obtained that the clamping force by the inner contact type is more stable than the clamping force by the outer contact type.
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Shuji HOSOKAWA, Tomohiro MORIKANE
Article type: Article
Pages
63-64
Published: August 05, 2003
Released on J-STAGE: August 01, 2017
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This report deals with the interaction in the tightening of the group bolted rectangular plates. The initial clamping force of the bolt changes by the influence of the bolt next tightened in the group bolted, and it can't get the clamping force of the purpose. The equation that the clamping force to decrease due to the interaction is calculated is deduced. The tightening experiment with two bolts is performed to examine this equation. The experimental results agree approximately with the equation, and the validity of the equation is confirmed.
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Shinji HASHIMURA, Yukitaka MURAKAMI, Kazuhiro OISHI, Norihiro IYANAGA
Article type: Article
Pages
65-66
Published: August 05, 2003
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The influence of the configuration of the bearing surface on bolt loosening under horizontal micro vibrational loading was experimentally investigated. The configurations of the bearing surface influence the characteristics of loosening of bolted joints under micro vibration. The clamping force also influences the characteristics of fatigue and loosening of bolted joints under horizontal micro vibration.
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Shinji KASEI, Satoshi YOSHIDA, Yuji SHIRAKI, Manabu OKADA, Hirohito MA ...
Article type: Article
Pages
67-68
Published: August 05, 2003
Released on J-STAGE: August 01, 2017
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A close relation exists between slips at bearing surfaces and occurrences of loosening in threaded fasteners. It is considered that any slip, even if its value is minute, can become a direct cause for the loosening rotation. To investigate the loosening mechanism from this point of view, a transverse loading type experimental apparatus was constructed and experiments were started. This report presents some experimental results and related considerations about state of progress of the loosening, the bearing surface slip vs. the loosening rotation, and so on. The results obtained suggest that it is important to suppress the slip completely in order to prevent the occurrence of the loosening rotation.
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Susumu KUMAKURA, Kumiko SAITO
Article type: Article
Pages
69-70
Published: August 05, 2003
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In our previous paper, the authors reported that loosening was not occurred in the bolt nut joints with higher accuracy of the tolerance at the engaged screw threads from our loosening experiments in which M20 screw threads were used, In addition, it was demonstrated that the loosening was not easily occurred in the bolted joints in the which nuts with flanges were used. Thus, in the present paper, for verification of the loosening sources experiments were performed to measure the nut radial deformations and the friction coefficients by using the nuts mentioned above. As a result, it was confirmed that an amount of the loosening was decreased as the nut radial deformation was decreased.
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Toshiyuki SAWA, Rie HIGUCHI
Article type: Article
Pages
71-72
Published: August 05, 2003
Released on J-STAGE: August 01, 2017
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The stresses of a bolted flange connection with a cover of pressure vessel in which a spiral wound gasket is inserted, under internal pressure are analyzed taking account a hysteresis of the gasket by using the finite element method (FEM). The leakage tests were also conducted using an actual bolted flange connection with a cover of pressure vessel with a spiral wound gasket. Using the contact stress distribution of the bolted flange connection under internal pressure and the tightness parameter, the values of the new gasket constant were obtained by taking into account the changes in the contact stress. The sealing performance was evaluated by the new gasket constants.
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Toshiyuki SAWA, Wataru MAEZAKI
Article type: Article
Pages
73-74
Published: August 05, 2003
Released on J-STAGE: August 01, 2017
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The contact gasket stress distributions of a non-circular flange connection with a compressed asbestos sheet gasket subjected to internal pressure were analyzed taking account a hysteresis of the gasket by using finite element method (FEM). Leakage tests were also conducted using an actual non-circular flange connection with a compressed asbestos sheet gasket under internal pressure. By using the contact gasket stress distributions and the results of the leakage tests, the new gasket constants were calculated. A difference in the new gasket constants was substantial between the values obtained from the present study and those by the PVRC procedure. In addition, a method to determine the initial clamping bolt force (bolt preload) for a given tightness parameter was demonstrated.
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Naoaki NODA, [in Japanese], [in Japanese], [in Japanese], [in Japanese ...
Article type: Article
Pages
75-76
Published: August 05, 2003
Released on J-STAGE: August 01, 2017
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In the piping of the food industries, chemicals, hot water, sterilization by steam, and cleaning are carried out every day to hold generation of bacteria. Therefore, the gasket is easy to deteriorate, and results in leak from the joint or contamination of the gasket piece into the product. This paper deals with a new seal system between flange joints without using gasket. This sanitary gasketless flange includes a groove and annular lip that is machined in one of the flange being in contact with the other flange to form a seal line when the flanges are assembled. In this study, a new seal system is considered useful for food industries. Fundamental dimensions are examined for SUS304 to obtain the best sealing performance and optimal shape.
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Takumi TANDOU, Hirotaka YAMAGUCHI, Tadaatsu SATOMI
Article type: Article
Pages
77-78
Published: August 05, 2003
Released on J-STAGE: August 01, 2017
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This study is related on the performance improving of the aerostatic lead screw. It is characterized by the followings; free from friction and wear, no trouble due to air leakage, and so forth. Therefore, an aerostatic lead screw is adopted in the precision positioning device by reason of achieving higher positioning accuracy. We designed and manufactured the aerostatic lead screw of 200mm stroke as second trial production. As a result, we succeeded to measure; maximum cumulative pitch error of every 3 pitches is 13μm, angle of male screw thread is 60°3', static stiffness toward axial direction is 3.3N/μm experimentally when a clearance between male and female screws is 17μm.
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Hiromu HASHIMOTO
Article type: Article
Pages
79-80
Published: August 05, 2003
Released on J-STAGE: August 01, 2017
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This first report describes the theoretical modeling of friction coefficient between uncoated paper-web (newsprint; for example) and steel roller. In the modeling, the paper base is approximated by the linear spacing and the surface asperities are treated as rigid body. Introducing the contact mechanics and assuming the Gaussian distribution of surface asperities, the mixed friction coefficient is formulated theoretically for a wide range of roller surface velocity, in which the air film thickness between the web and roller is estimated based on the foil bearing model. A comparison between the predicted results and the experimental results will be presented in the second report.
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Masakazu OKAJIMA, Hiromu HASHIMOTO
Article type: Article
Pages
81-82
Published: August 05, 2003
Released on J-STAGE: August 01, 2017
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This second report describes the experimental study for friction coefficient between the paper-web and rotating steel roller. The newsprint is used as uncoated paper-web. Euler's belt formula is applied to calculate the friction coefficient form the measured data on tension increase. The measurements are carried out by changing five design parameters such as web width, wrap angle, tension, roller diameter and roller surface velocity. The measured results are compared with the predicted results by the friction model presented in the first report. Good agreement can be seen between the predicted results and measured results.
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Hiromu HASHIMOTO, Yasushi ENDO
Article type: Article
Pages
83-84
Published: August 05, 2003
Released on J-STAGE: August 01, 2017
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This first report describes the numerical analysis method to estimate to the static and dynamic characteristics of gas film thrust bearings with complex geometric such as spiral grooved and herringbone bearing. The modified divergence formulation method (MDF) and narrow groove theory (NGT) are applied to both types of bearings. The calculated results are compared with the experimental results for checking the accuracy of numerical analysis. NGT generated relatively large error than MDF in the analysis of dynamic characteristics.
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Masahisa FURUKAWA, Hiromu HASHIMOTO
Article type: Article
Pages
85-86
Published: August 05, 2003
Released on J-STAGE: August 01, 2017
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This second report describes the accuracy of measurements of the static and dynamic characteristics of several types of air film thrust bearings. The specially designed test rig is used to measure the air film thickness, friction torque, spring and damping coefficients of air films under the high speed operation conditions from 20,000rpm to 40,000rpm. It is verified that the maximum error in the measurement is less than 10% and the measurement method presented here has an enough accuracy in the actual applications.
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Takashi NUMAKURA, Hiromu HASHIMOTO
Article type: Article
Pages
87-88
Published: August 05, 2003
Released on J-STAGE: August 01, 2017
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The inertia effects of oil-whip generated in full-circular oil film journal bearings were originally found by Pinkus. After this interesting reporting, several research workers tried to develop the theoretical and experimental studies on the phenomena. However, only a few papers can be available on this topics in the past several decades, and it is not yet clear the mechanism of inertia effects of oil-whip even in the present days. This report describes the experimental study of examining the inertia effects in full circular journal bearings lubricated under the submerged conditions relating with the visual observation of cavitation pattern.
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Yasumi OZAWA
Article type: Article
Pages
89-90
Published: August 05, 2003
Released on J-STAGE: August 01, 2017
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The complicated phenomena such as pressure depressions, shock waves and the negative pressure, are detected in the air flow with a large bearing clearance or high supply pressure in an externally pressurized gas-lubricated circular thrust bearing. The pressure depression, which decreases the bearing load carrying capacity, is an undesirable phenomenon occurring in this gas bearing. The negative load carrying capacity for the non-contacting suspension support of the object utilizing the negative pressure of this gas bearing is investigated experimentally, and is also discussed in this paper.
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Yasumi OZAWA, Takashi OKADA
Article type: Article
Pages
91-92
Published: August 05, 2003
Released on J-STAGE: August 01, 2017
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The heat curing oil film method using thermosetting property oil film is a new oil film method. The heat curing oil film method, in which not only the plane flow pattern in wall surface but also oil film thickness of the steady flow can be measured, is newly developed. The heat curing oil film method is a very useful method for visualization of an air flow in the clearance of an externally pressurized gas-lubricated circular thrust bearing with a central supply hole. The rheological characteristics and the effect of the oleic acid on the rheological characteristics of the heat curing oil without hardener and titanium dioxide are investigated in this paper.
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Atsushi KORENAGA, Shinya SASAKI
Article type: Article
Pages
93-94
Published: August 05, 2003
Released on J-STAGE: August 01, 2017
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This paper describes the properties of the journal bearing using liquid crystal (LC) as a lubricating oil in order to realize the real-time control of the hydrodynamic lubrication characteristic. We focused on the pressure distribution especially in negative pressure region. The measurement of negative pressure and observation of oil film rupture were carried out under applying the voltage. The results showed that the oil film rupture region of the liquid crystal was a little narrower than it of the mineral oil, and that oil film rupture region of the liquid crystal expands by applying the voltage.
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