Effects of Wire Twisting on Coiling and its Application to Non-Linear Helical Extension Spring

摘要

The twisting effects of wire in coiling on the pitch or on the initial tension are investigated. As a result, it is clarified to process pitch or initial tension by twisting wire under a suitable feeding condition without adjusting the coiling points. The direction of twist agrees with the winding direction of compression coils, and the more the angle of twist per unit wire length increases, the larger the pitch of coils becomes. On the other hand, the more the negative angle of twist per unit wire length icreases, the larger the initial tension of coils becomes. And it is clarified that the highest level of the initial tension can be attained by the wire twisting method. If the initial tension varies monotonically in an extension spring, a new type non-linear spring property can be attained. The wire twisting method is also useful to produce such a non--linear spring. Therefore the relation between the non-linear spring characteristics of the formed coils and the twisting conditions of wires have been studied. The experimental results agree qualitatively with the theoretical ones.