号数	ばね論文集４１号（１９９６年）
ページ数	pp.1-5
種類	論文
論文名	チタン合金製弁ばねの開発
Title	Development of Valve Spring Made of Titanium Alloy
著者	薮下 毅士・高村 典利・丹下 彰
Author	Takeshi YABUSHITA・Noritoshi TAKAMURA・Akira TANGE
抄録	チタン合金Ｔｉ‐１３Ｖ‐１１Ｃｒ‐３Ａｌの疲労強度に対する時効条件を調べ，耐摩耗性の高いコーティング法を研究した。この結果を基にエンジン性能を向上する弁ばねを開発した。チタン合金の疲れ強さは，時効処理温度が高く，引張強さが低いほど高く，鋼と逆になる。Ｎｉ‐Ｐ，またはＮｉ‐Ｐ＋Ａｕ‐Ｎｉの無電解めっきは高い耐摩耗性を与える。上記無電解めっきを行ったチタン合金製弁ばねは，モータリング試験の結果，重量で５７％減の軽量化ができた。
Abstract	We have investigated the influence of aging conditions on fatigue strength of titanium alloy and studied the wear resistant coatings for titanium alloy. Utilizing the results, we have developed the valve spring made of titanium alloy in order to increase engine speed and lighten engine weight. The main results obtained are summarized as follows: 1)Tensile strength dependence of fatigue strength in Ti-13V-11Cr-3AI alloy is opposite to tensile strength dependence in steel. 2)Settling performance of Ti-13V-11Cr-3AI alloy is improved as increasing tensile strength, and settling performance is equivalent to steel with higher strength. 3)Ni-P electroless plating and Ni-P+Au-Ni electroless plating are excellent methods as wear resistant coating for titanium alloy. 4)Ti-13V-11Cr-3AI alloy springs with optimum tensile strength and coating by Ni-P electroless plating or Ni-P +Au-Ni electroless plating pass the motoring test. 5)Titanium alloy springs with optimum tensile strength and coating by Ni-P electroless plating or Ni-P+Au-Ni electroless plating in comparison with steel springs lead to a 13 percent decrease in free height and a 57 percent decrease in weight.
著者の所属	日本発条株式会社
Belonging	NHK Spring Co., Ltd.
Key Words	Titanium alloy, Valve spring, Fatigue strength, Aging, Wear resistant coating,Motoring test