ばね論文集
Online ISSN : 1348-1479
Print ISSN : 0385-6917
ISSN-L : 0385-6917
2022 巻, 67 号
選択された号の論文の11件中1~11を表示しています
論文
  • 榎田 裕行, 林 博昭
    2022 年 2022 巻 67 号 p. 1-8
    発行日: 2022/03/31
    公開日: 2022/10/01
    ジャーナル フリー

    Cold-formed springs are also called precision springs and are one of the mechanical elements that require high spring accuracy shape and spring constant. In order to improve the accuracy of these springs, it is indispensable to improve the accuracy of each factor related to the spring constant. In this paper, we will discuss the variations in elastic modulus and coil diameter after low-temperature annealing, which are considered to play an important role. Especially, we reviewed a difference in elastic modulus depending on the measurement method, and the variations in coil diameter after low-temperature annealing, and then studied the cause of these issues suggesting the problems and remaining issues.

  • 小竹 茂夫
    2022 年 2022 巻 67 号 p. 9-14
    発行日: 2022/03/31
    公開日: 2022/10/01
    ジャーナル フリー

    In this study, we investigate the amount of plastic deformation caused by the settling of a pearlite steel compression spring under constant load heat treatment in various temperatures, and the amount of temporal change of elastic after effect in the treated spring. The relationship between the relaxation time and the heat treatment temperature has been discussed. The relaxation time of elastic after-effect became minimum at A0 transformation point and showed λ transition like abnormality. This decrement in relaxation time indicates that dislocations change its behavior from plasticity to elasticity. It corresponds to the extension of elastic limit in low-temperature annealing. It also suggests that the Curie point of magnetic transition in cementite affects the mechanical property of the spring.

  • 谷片 暁, 長 弘基, 山路 敦士, 中島 聡吾, 松田 鶴夫
    2022 年 2022 巻 67 号 p. 15-21
    発行日: 2022/03/31
    公開日: 2022/10/01
    ジャーナル フリー

    The single coiled torsion spring made of Ti-Ni shape memory alloy (SMA) is expected to be used as a torsion spring that is smaller in size and has a larger displacement than torsion springs made of conventional spring materials. However, heat-treatment is necessary for Ti-Ni SMA to memorize the spring shape. Furthermore, it is well known that the shape memory and mechanical properties of Ti-Ni SMA are varied with the variation of heat-treatment condition. Therefore, spring characteristics of Ti-Ni SMA torsion spring is expected to be affected by heat-treatment condition. In this study, effects of heat-treatment condition on generating force and functional degradation characteristics of single coiled torsion springs made of Ti-Ni SMA wire are investigated. In result, the output power and functional degradation characteristics of Ti-Ni SMA torsion springs tend to decrease with the increment of heat-treatment temperature and heat-treatment time. This tendency is thought to be caused by the decrease of internal stress due to the decrease of deformation texture or precipitates with the increment of heat-treatment temperature or time. Meanwhile, fatigue life tends to decrease with increment of generating force. This tendency is thought to be caused by the increase of deformation stress due to the increase of generating force.

  • 池田 悠, 松尾 卓摩, 納冨 充雄
    2022 年 2022 巻 67 号 p. 23-26
    発行日: 2022/03/31
    公開日: 2022/10/01
    ジャーナル フリー

    Due to the need of increasing fuel efficiency, the weight of springs and many other components in automobiles need to decrease their weight. The weight reduction can be achieved by increasing the strength of material, however, it may cause the problems of reduced workability, toughness and durability. Even increasing the material strength, enhancing their fatigue properties will expand the service life of them, i.e., delaying the initiation of cracks. A crack initiation is caused by the accumulation of dislocations, which is resulted by yielding on the surface due to repeated loading. Finite element analysis was recently available to apply the stress distribution analysis of a complicated shape, e.g., a helical coil spring subjected to compression loading. In this research an attempt was made to presume the point of the fatigue fracture initiation in coil springs according to the distribution of Mises stress, that is the crucial index of yielding phenomenon. The point inside and surface of a coil spring wire at which the Mises stress has its maximum value is the same place as a crack nucleation during fatigue progress according to referring experimental papers.

  • 小山 弘樹, 有川 秀一, 納冨 充雄
    2022 年 2022 巻 67 号 p. 27-33
    発行日: 2022/03/31
    公開日: 2022/10/01
    ジャーナル フリー

    A tapered coil spring is the one whose wire diameter isn't constant and continuously changes. The spring possesses the non-linear stiffness which increases with increasing the load applied. Although its application is the axle spring for railway car because of passively changing the stiffness under the applied load that relates the number of passengers, making formula is difficult due to the gradually diameter change of tapered wires. Finite element method has often been applied to the analysis of mechanics for the springs and it should be found the appropriate end turn shape of the springs for real deformation of the coil and we found the optimized end turn for constant deformation. The stiffness of the spring follows the approximate formula on each region in different diameter before contact between wires and the formula on the region of thick wire after contact. The stiffness of the spring actually could be determined for varying the pitch and predicted using finite element method.

  • 山口 航矢, 石田 祥子
    2022 年 2022 巻 67 号 p. 35-42
    発行日: 2022/03/31
    公開日: 2022/10/01
    ジャーナル フリー

    This study aims to design vibration isolators, using two types of coil springs with different hysteresis, and evaluate the vibration isolation performance of each design. Vibration isolation is achieved through nonlinear spring characteristics of the isolators using an origami-inspired foldable structure attached to the coil spring, which have quasi-zero spring stiffness. However, the two vibration isolators exhibited different load-displacement curves between expansion and contraction processes. Due to the hysteresis of the spring characteristics of the vibration isolators, the quasi-zero stiffness was not exactly obtained. As a result of the excitation experiment, it was found that the vibration isolator with small load difference had low resonance frequency. This fact indicates that the magnitude of load difference affects the vibration isolation performance, and it is important to select a coil spring with small load difference in order to improve the performance.

  • 浅見 敏彦
    2022 年 2022 巻 67 号 p. 43-52
    発行日: 2022/03/31
    公開日: 2022/10/01
    ジャーナル フリー

    Transfer functions are often employed to evaluate the vibration characteristics of mechanical and electrical systems. Within a group of transfer functions, some particular ones have the property that swapping the coefficients of the two terms in the equation does not change the properties of the original function. Such functions are said to have a reciprocity property. Mechanical vibratory systems typically have three transfer functions; namely, compliance, mobility, and accelerance. For a single-degree-of-freedom system, the mobility transfer function has the reciprocity property; for a two-degree-of-freedom system, no transfer function has the reciprocity property; and for a three-degree-of-freedom system, one transfer function has the reciprocity property. This paper shows that the presence of transfer functions with the reciprocity property is extremely important for obtaining simple optimal design formulas for dynamic vibration absorbers.

  • 中曽根 祐司
    2022 年 2022 巻 67 号 p. 53-60
    発行日: 2022/03/31
    公開日: 2022/10/01
    ジャーナル フリー

    This study has investigated the effects of coil turn position on the principal stresses and the correction factors, Fi (i=I, II and III) of the three modes of the stress intensity factors for a semi-elliptic surface crack on the outer surface of a compression coil spring. For this purpose, 3D finite element stress analyses have been made on a compression coil spring having a surface crack on the outer surface of its wire at every 0.5 turn from n=0.5 to n=4.5. The maximum principal stress, σ1, was also calculated by FEM and found to vary as cosine function of number of turns, n. The value of σ1 took maxima for half integer coil turns, i.e., n=0.5, 1.5, 2.5, …, whereas minima for every coil turn, i.e., n=1, 2, 3, …. The principal stress fluctuation range was found as small as 4.6% of its center value. The correction factor FI for the mode I stress intensity factors of the semi-elliptic surface crack also varied as cosine functions of n in the same manner as σ1 at all the positions of crack peripheries investigated. The largest mode I correction factor fluctuation range was as large as 22.9% of its fluctuation center value. The variations of FI value with n can be distinguished into 5 groups according to the distance from the wire surface. This tendency was caused by the variations of FI value with the eccentric angle φ of the crack which are expressed as quartic functions of φ almost symmetric with the φ=90° (deepest point). The FI value took minima at the wire surface and second minima at the deepest point of the crack, and the value increased as the point got closer to the surface. The FI value varied from 0.47 to 0.69 with the geometrical parameters n and φ. The FI value was found dominant among the three modes of correction factors, since the values of the correction factors of the other modes, i.e., FII and FIII, were at most 8.3% and 14.3% of the FI value, respectively.

  • Atsumi OHTSUKI, Tomoyuki IWATA
    2022 年 2022 巻 67 号 p. 61-67
    発行日: 2022/03/31
    公開日: 2022/10/01
    ジャーナル フリー

    In elements used as flexible linking devices and structures, the main characteristic is the occurrence of a fairly large deformation within the elastic limit of the element material. Many of these devices play the role of springs. This property as a spring is of both academical and industrial interests. A hexagonal frame structure is used widely in construction elements, for example, an indwelling stent (:a medical device), a CNT (carbon nanotube), a fishing net, a food net, a gabion, a core of sandwich structures, etc. In such elastic structures, a large deformation characteristic is observed. It is very important to investigate the large deformation behavior quantitatively and qualitatively. However, studies on large deformations have been concerned mainly with a single member (cantilever beam and simple supported beam), and in some particular occasion, cases for multiple members have been analyzed by Kerr and Khwaji. In this paper, a hexagonal frame structure with rigid joints, which is subjected to either tensile or compressive loading diagonally at the pair of opposite frame member or rigid joint was analyzed. Analytical solutions for arc lengths, displacements, deflection angles and bending moments, etc. are derived in terms of elliptic integrals and some solutions are compared with the experimental data. The agreement between analytical and experimental results is found to be fairly close. Therefore, it was proved that the present analytical theory can be effective for large deformation analysis of a hexagonal frame used as a kind of spring. In other words, it was found that the proposed theory would be of great help in elucidating the large deformation of stents with hexagonal structures.

  • 近藤 涼太, 高橋 宏治
    2022 年 2022 巻 67 号 p. 69-73
    発行日: 2022/03/31
    公開日: 2022/10/01
    ジャーナル フリー

    The effects of shot diameter on the bending fatigue strength test for shot-peened spring steel (JIS-SU-P9A) were investigated. The bending fatigue tests were conducted on the specimens shot peened with shot diameters of 0.2 and 0.7 mm at a stress ratio of R=0. The results of the bending fatigue tests showed that as the shot diameter decreased, the fatigue strength limit increased. It was also confirmed that there was a correlation between the residual stresses, Vickers hardness and the fatigue strength. Furthermore, the fatigue limits of the specimen were successfully predicted by using the prediction equation based on the parameter model.

  • 辻 俊哉, 小林 祐次, 政木 清孝
    2022 年 2022 巻 67 号 p. 75-82
    発行日: 2022/03/31
    公開日: 2022/10/01
    ジャーナル フリー

    In order to investigate the effect of residual stress distribution pattern in the specimen on the fatigue crack initiation behavior and fatigue strength at 2×107 cycles, rotating bending fatigue tests were conducted for carburized SCM420H steels treated with several shot peening conditions. In the case of a specimen having a S-type residual stress distribution in which a peak residual stress exists inside the specimen and the surface residual stress is smaller than the peak residual stress, the specimen fractures in surface fracture type under high stress load and in internal fracture type under low stress load. The boundary stress between surface and internal fracture type is the lower limit stress at which the surface crack can proceed through the depth where the peak of the residual stress exists. On the other hand, most of the SP-treated specimen fractures in internal fracture type and clear fish-eye pattern was observed on the fracture surface. And the crack initiation site was at the location of transgranular cracking that occurred in a region deeper than the hardened layer. It was predicted that the fatigue strength at 2×107 cycles of SP treated specimen corresponds to the crack generation limit when the residual stress peak position is relatively shallow. Furthermore, it was predicted that the fatigue strength at 2×107 cycles corresponds to the crack propagation limit when the residual stress peak position is relatively deep.

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