关键词: 插补, 非均匀有理B样条, 空间凸轮, 修正正弦曲线

Abstract: On the problem of lower stability, bigger noise, quicker wear of spatial cam during high speed transmission, a new technique of design and manufacturing of spatial cam based on non-uniform rational B-splines(NURBS) is proposed. To construct geometric locus of follower, NURBS is used to fit modified-sine curve. The theory of envelopes of one-parameter family of surfaces is used to determine the surface geometry of cylindrical cam profile. The spatial cam is machined on CNC machine with NURBS interpolation to obtain high precision and smoothness. It is verified that the motion curves (including curves of displacement, velocity and acceleration) of follower obtained by using NURBS is smoother than that obtained by widely used modified-sine method. The noise of spatial cam machined by NURBS interpolation method is lower than that of usually used linear or arc interpolation method. Therefore, the design method based on NURBS is simple and practicable. The spatial cam manufactured by using this method has the advantages of stable transmission, low noise, and long lifespan during high speed transmission.

Key words: Interpolation, Modified-sine curve, Non-uniform rational B-splines, Spatial cam