Transactions of Japan Society of Spring Engineers
Online ISSN : 1348-1479
Print ISSN : 0385-6917
ISSN-L : 0385-6917
Volume 1984, Issue 29
Displaying 1-13 of 13 articles from this issue
  • Mikio NISHIHATA, Yoshiaki HAYASHIBE, Shohei ABE
    1984 Volume 1984 Issue 29 Pages 1-5
    Published: March 31, 1984
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    Mechanical properties and corrosion resistance of solder clad beryllium-copper alloy springs have been investigated.
    (1) Cold worked solder clad beryllium-copper alloy springs have a good surface and strong adhesion, and show a high corrosion resistance. The tensile strength, hardness, and spring limit of that alloy spring are slightly lower than the respective value of unclad beryllium-copper alloy springs, but the fatigue strength of the clad spring is not affected by solder clothing.
    (2) Heat of about 300°C can not separate solder from the base metal of the clad alloy spring. Both clad alloy springs and unclad alloy ones show their respective maximum mechanical strength at about 310°C.
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  • Yoshiharu NIIKURA, Shigeru KAWAGUCHI, Shigemi SATO
    1984 Volume 1984 Issue 29 Pages 6-11
    Published: March 31, 1984
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    Shape memory alloys receive wide attention as a functional material having an energy exchange function (thermal energy to mechanical energy). Applications of the alloy are actively developed and have already included some spring products.
    Systematic studies of the alloy have been made in recent years, but very few reports on features of shape memory alloy springs are found.
    This paper describes the investigation of the best fit heat treatment requirements for TiNi shape memory alloys and of their useful service range as a shape memory or a super elasticity material based on material and spring characteristics.
    The result shows that the best fit heat treament temperature is 500°C because of the thermal hysteresis and the recovery force at the transformation point, the useful service range as a material is that the stress is not greater than 95kgf/mm2 and the temperature is the Ms point plus 115°C or less, and the useful service range as a spring is that the shear strain is 3.7-6.0% or less and the temperature is not higher than the Ms point plus 127°C.
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  • Masayoshi SHIMOSEKI, Yoshihiro HAYASAKA
    1984 Volume 1984 Issue 29 Pages 12-18
    Published: March 31, 1984
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    The leaf tip method, based on the small displacement theory, of a conventional analytic method for leaf springs can be applied to only linear analysis. However, non-linear phenomena concerned with leaf springs are not rare; so that the RBSM method of the simplest FEM is applied to the analysis of those phenomena. The two major phenomena to be analyzed were behavior and setting of a truck suspension and the analysis of them well agreed with the experimental result.
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  • Masayoshi SHIMOSEKI, Yoshihiro HAYASAKA
    1984 Volume 1984 Issue 29 Pages 19-29
    Published: March 31, 1984
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    Various kinds of springs such as herical springs have space curved center lines, but their designing formulae, especially stress analysis methods, have not yet been established, and causing serious problems for industry.
    We applied Wittrick's eguation based on the space curved rod theory to the analysis of the stress distribution across the cross-section of various type of herical coil springs. Moverover, since it is difficult to solve a set of there differential equations, we approximated it using a simple and a general finite differential methods, even if the exactness is last a little.
    On the compression problems of coil springs with perfectly grinded ends and without grinded ends, we clarified all boundary conditions and contact conditions at the end turns. Furthermore, we demonstrated the propriety of this analysis.
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  • Hiroshi KOYAMA, Roh KITAMURA, Akira TANGE
    1984 Volume 1984 Issue 29 Pages 30-37
    Published: March 31, 1984
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    Nowadays, a car suspension is used under higher stress conditions with more weight saving needs of cars. As a higher hardness suspension is used, the notch sensitivity, being beforehand taken notice of, is a more important problem to be solved.
    This paper describes the investigation on influences of hardness of SUP 6, SUP 7, and SAE 9254 steels on their property of fatigue crack propagation on the basis of fracture mechanics to quantify the notch sensitivity associated with increasing hardness.
    The investigated results are as follows:
    (1) Properties of fatigue crack propagation hardly depend on the difference between those three steel types and greatly depend upon hardness of material within this investigation range.
    (2) The fatigue crack propagation velocity in an intermediate growth rate regime is able to be formulated by Paris' law as a function of hardness; so that a higher hardness gives a greater propagation velocity.
    (3) The threshold stress intensity factor range decreases against increase of hardness and the notch sensitivity grows with increasing hardness.
    (4) The investigation in a high growth rate regime is not conducted yet, but the fatigue crack propagation velocity in the high growth rate regime is supposedly increased with increasing material hardness because a fracture toughness decreases with hardness.
    (5) Fatigue fractographs vary with great dependence on the stress intensity factor range and material hardness.
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  • Yoshiharu MUTOH, Kohichi TANAKA, Shuichi SAKODA, Tadahisa NAKAMURA, To ...
    1984 Volume 1984 Issue 29 Pages 38-47
    Published: March 31, 1984
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    One of the factors decreasing a fatigue life of leaf springs is fretting fatigue caused by contact between leafs and cyclic bending stress.
    In the present study, the conventional fretting fatigue test of small spring steel specimens with the bridges of the same material and also with spacer material (Delrin) has been made by using a general fatigue test machine. The results are as follows:
    (1) The plain fatigue limit and the fretting fatigue limit of SUP 9 steel are respectively 620Mpa and 320Mpa; the fretting remarkably decreases a fatigue limit and a fatigue life.
    (2) The propagation process of fretting fatigue cracks is characterized by the debrislike crack which initiates and propagates under an influence of large plastic deformation, by the first stage crack which is greatly affected by stress concentration by the contact by the intermediate stage crack corresponding to a transition stage between the first stage crack and the second stage crack with a weakened stress concentration, and by the second stage crack which comes out of a stress concentration area.
    (3) In the case of the bridge material is identical with the spring material, the friction coefficient increases with a relative slip amplitude and tends to saturate at the value of 0.6.
    (4) Use of Delrin as a spacer between bridge and specimen remarkably improves the fretting fatigue life. Consequently, the life approximately equals the plain fatigue life.
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  • Yoshinori TANIMOTO
    1984 Volume 1984 Issue 29 Pages 48-57
    Published: March 31, 1984
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    Recently, the high tensile strength fine wire for precise spring is required more higher strength, because the spring for mechanical parts of electrodevice and electronic instrument demanded more compact in its design.
    Usually, the fine wire for precise spring had to high elasticity, fatigue, especially anti-corrosive properties.
    Typical hard drawn stainless steel fine wire has superior the anti-corrosive and heat resistant properties but some limitation to allow high design stress for spring resulted from lower yield strength compared with typical piano wire.
    The main concern of this paper is to make a series of mechanical, fatigue, anti-corrosive properties of the improved hard drawn high tensile strength stainless steel wire (New type wire) made from special wire drawing method compared with typical SUS 304-WPB grade wire and typical piano wire.
    In conclusion:
    (1) The new type wire has equivalent the value as the tensile strength of SWP-B grade of piano wire in JIS.
    (2) The spring of the new type wire has more improvement of the spring properties after stress-relieved (bluing).
    (3) The spring of the new type wire has remarkable progress in the endurance limit of fatigue and the deformation of the tested spring compared with typical SUS 304-WPB spring.
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  • Toshio OZONE, Hideaki KATO, Morimasa IWATA
    1984 Volume 1984 Issue 29 Pages 58-62
    Published: March 31, 1984
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    Fatigue fracture of springs especially for automotive suspension is frequently caused by corrosion, from which it is difficult to prevent the spring surface by coating due to peeling off in an early stage. As a substitute for coating, the application of diffusion coating of Al and Ni-Al alloy was brought into experiment.
    Diffusion coating layer of about 50μm in thickness was observed after heating the specimens with metal sprayed layer at a temperature of austenite region for 10 minutes. After that, the specimens were quenched into oil as usual, then they were tempered at 450°C to be shot-peened.
    The diffusion coating layers were found to consist of intermetallic compounds such as Fe2Al5 (η phase) for Al coating and Ni3Al (γ′ phase) for Ni-Al alloy coating. The hardness of the Al diffusion coating layer was HV 550 and for Ni-Al alloy coating it was HV 600.
    When a corrosion test was made under cyclic exposures between salt spray and air for 20 days, the specimens with diffusion layers exhibit no corrosion pit on the surface, but etch-pits of about 0.13mm in depth were found on the surface with no diffusion coating layer. It was also found that the thickness of metal sprayed layers prior to heating is responsible for the amount of residual stress on the surface after shot peening.
    But in case that the thickness of metal sprayed layer was restricted to a thickness within 50μm, the effect of shot peening was maintained, giving the specimens a fatigue strength equivalent to that with no diffusion layer. The thickness of 50μm of metal sprayed layer is just enough to be fully absorbed into steel, leaving no scale to interfere in shot peening after heat treatment.
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  • Makoto SAITO, Yasuaki KASAI, Masashi MIZUNO, Yukio ITO, Hiroshi KOYAMA
    1984 Volume 1984 Issue 29 Pages 63-69
    Published: March 31, 1984
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    A new tapered-rod forming process has been developed and an experimental-scale prototype continuous production system has been set up. In this process, temperature-dependency and strain-rate-dependency of the material's flow stress are utilized as a working principle. That is, a rod with arbitrary taper can be formed by rapid pulling of a bar with precisely controlled longitudinal temperature distribution. This process satisfies some important industrial requirements such as high dimensional accuracy, nearly 100% yield, high production rate (1rod/20-25sec), and low total energy consumption.
    Tapered rods manufactured by the system have been tested with regard to properties of a processed segment itself, and to properties of a tapered-rod coil spring as a final product.
    Results are;
    1) Tensile properties and fatigue strength after heat treatment are not altered by processing.
    2) Coil springs made from tapered rods manufactured by the new process and by the conventional turning method have the same spring properties, fatigue properties, and loadloss resistance.
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  • Takahiko KUNO, Kazunori TSUSHIMA, Masao MIZUNO
    1984 Volume 1984 Issue 29 Pages 70-73
    Published: March 31, 1984
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    Positioning of pitch tools and the offset of coiling point for the pitching of coils in a single-point coiling system are investigated theoretically and experimentally.
    The main results obtained are as follows.
    1) The offset of the coiling point has more important effect upon the pitch of coils than the lift of pitch tools.
    2) The pitching process of coils by the offset of coiling point is due to the torsion of the wire between the wire guide and the coiling point. The relation between the offset and the pitch of coils becomes approximately linear.
    3) Elasto-plastic analysis is available especially for the case of pitching of coils because of its small torsinal deformation.
    4) The contact condition of the wire to the coiling tools has an important effect on the pitch of coils.
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  • Kazunori TSUSHIMA, Takahiko KUNO, Masao MIZUNO, Koji NAKAYAMA, Susumu ...
    1984 Volume 1984 Issue 29 Pages 74-83
    Published: March 31, 1984
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    In this paper, we describe an experimental study of characteristics: surface condition and working accuracy: of coil end, when a series of cold wound coil spring are cut off with abrasive cut-off wheel. The summary of the experimental results is shown below.
    (1) As cut-off feed speed increases, cut-off wheel wear amount does in proportion to it. But cut-off wheel which abrasive wear amount is lowest is A100N.
    (2) Burn mark and burr which are producted in coil end when a series of cold wound coil springs are cut off, are removed in heat treatment and shot peening.
    Cut-off wheel which is applicable for these conditions is WA100J.
    (3) Inclination of coil outside face belongs within 2nd class of JIS B2707. And using WA100J cut-off wheel, the number of coil springs in less than 1st class of JIS B2707 increases.
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  • [in Japanese]
    1984 Volume 1984 Issue 29 Pages 84-114
    Published: March 31, 1984
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    The committee aims to promote an investigation concerning fabrications, usages and properties of high temperature springs and its materials to contribute to improved safety designing of the high temprature components.
    At the first step, we programed to undertake a questionnate towards makers and users of springs, and manufactures of spring materials, so as to grasp a recent trend of the domestic high temperature springs. The questionnate contains the following matters for investigation: fabrication and usage of the springs; manufacturing process of the spring materials; problem, counterplan for problem, and estimated tendency at future for the high temperature springs and materials.
    Available informations were obtained from the results of analyses for answers of the questionnate concerning the following present situations: service temperatures, types of materials, usages, stress ranges, geometries of the springs, sizes of lots, costs of materials, design lives, and the various problems. Summarizing the results, it was concluded that a collection and a systematization of the high temperature data for designing was the most important problem in the present.
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  • [in Japanese]
    1984 Volume 1984 Issue 29 Pages 115-149
    Published: March 31, 1984
    Released on J-STAGE: February 26, 2010
    JOURNAL FREE ACCESS
    Corroion fatigue test of vehicle suspension springs is performed in several test condition. Each test springs are compared with used springs that is collected from field. Then most suitable corrosion fatigue test condition is find out. That is repetition of followings:
    Dipping in salt water, Loading of cyclic stress, Drying in atomosphere with dead load.
    This test procedure is able to simulate the field Corrosion circumstances and shorten test period.
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