| 摘要 |
<p>PROBLEM TO BE SOLVED: To enhance the rapture strength of a thin-walled part and to make reaction to a fingertip near to an ideal condition to easily conduct musical performance. SOLUTION: A thin-walled part 20 provided at the rear portion of a key 2 is formed to make its thickness gradually thinner with a fixed width from its front end B toward its rear end A. The distribution of the bending moment in the thin-walled part 20 is thereby reduced gradually from the front end B of the part 20 toward the rear end A. Therefore, a fixed stress (σc) is secured in respective parts of the thin-walled part 20 by reducing continuously the thickness of the part 20 to make constant the bending stress (σc) free from fatigue- failure from the front end B of the part 20 toward its rear end A, so as to enhance the rapture strength of the thin-walled part 20. The smaller thickness requires the smaller load according to the relation between the deflection of the thin-walled part 20 and its load, the rapture strength of the part 20 is enhanced and reaction to a fingertip comes near to an ideal condition to conduct easily musical performance, by balancing the bending stress (σc) with the load.</p> |
