| 号数 | ばね論文集４７号（２００２年） |
| ページ数 | pp.1-6 |
| 種類 | 論文 |
| 論文名 | マグネシウム合金コイルばね （AZ31線の機械的性質とばね加工性及びばね特性） |
| Title | Magnesium Alloy Coiled springs (Mechanical Properties, Spring Workabilities of AZ31 Wire and Spring Characteristics) |
| 著者 | 渡邉 啓輔1)・渡辺 浩太郎1)・久納 孝彦2) |
| Author | Keisuke WATANABE1)・Kotaro WATANABE1)・Takahiko KUNOH2) |
| 抄録 | 近年，機械構造物の小型化，軽量化が進むなかで，ばねにもより一層の軽量化が求められており，新たなばね用材料としてマグネシウム合金が注目されている．マグネシウムは実用金属中比重が最も小さく，振動の減衰能にも優れているが，既存のばね用材料に比べて引張強さや耐力が劣るので，合金化や加工，熱処理などにより機械的強度の向上をはかる必要がある．また，成形性についても明らかでない． そこで著者はマグネシウム合金線AZ31の機械的性質を明らかにするとともに，この線を用いたコイルばねの製作を試み，その成形性について調べた．また，コイル寸法やばね特性に及ぼす低温焼なましの影響を調べた． 主な研究結果を以下に示す． （1） マグネシウム合金AZ31は他のばね用線と比較しると，引張強さがきわめて小さいが，比重が小さいため，比強度は引張強さほどの違いはない． （2）供試線からばね指数が5.0程度のコイルばねを旋盤式コイリングマシンにより成形することができ，ばね用線としての成形性を一応満たしている． （3）マグネシウム合金線は，コイルばね成形時のコイル径のスプリングバック量が他のばね用鋼線に比べて約15％から30％大きい． （4）低温焼なましにより，外径はわずかに増加するが，自由高さについては大きな変化はない． （5）本実験の熱処理条件範囲内では，焼なまし温度を180℃以上にすると，かえって弾性限界値は低下する． |
| Abstract | Recently the downsizing and the weight saving of mechanical structures asked for springs lighter, and the
light metal alloys are paid attention to as spring materials. Magnesium is the lightest in the practical metals,
and it is excellent in the damping capacity. But the tensile strength and the proof stress of the pure
magnesium is much lower than the ones for other spring materials. Hence, it is necessary to improve its
strength by alloying, hardning, heat treatment, and by other processes. The workabilities of magnesium alloy
springs had not been studied, too. Therefore the authors studied the mechanical properties of magnesium alloy AZ31 and made coil springs from wires of a magnesium alloy AZ31 by a lathe type coiling machines. The workabilities of coils were studied. The effects of annealing on the dimensions of the coils and on the spring property were also studied. The main results are as follows; (1) Magnesium alloy wire AZ31 is much inferior to other spring wires, but not much inferior in specific strength because of small specific gravity. (2) It was possible to form coil of about 5.0 in spring index from wires of a magnesium alloy AZ31 by a lathe type coiling machines, so wires of a magnesium alloy AZ31 fill the workabilities as spring wires. (3) In magnesium alloy wire AZ31 the spring back of coil diameter is large compared with other spring steel wires. (4) By annealing the outside diameter increases but the free length hardly changes. (5) When the annealing temperature is over 180(℃) , the elastic limit of coiled springs deteriorates. |
| 著者の所属 | 1)慶応義塾大学 大学院 2)慶応義塾大学 |
| Belonging | 1)Graduate school of Science and Technology, Keio University 2)Faculty of Science and Technology, Keio University |
| Key Words | Magnesium alloy AZ31, Workabilities, Spring property, Annealing |