Research On Design And Non-equalization Machining Method For Spatial Cam With Oscillating Follower

Spatial cam mechanism has been widely used in machinery and equipment in all areas. However, the commonly used planar expansion methods for the design of spatial cam contour produce significant errors, because these methods incorrectly use the distance from the axis of the follower to the main spatial cam to replace the corresponding arc length on the spatial cam. HSIEH, et al and others used analytical methods to achieve higher accuracy, but these analytical methods have their own drawbacks since these methods are too complicated for practical use. Through the analysis of the errors created during the generation of spatial cam contour using the existing expansion methods, this paper proposes to include diverge angle in the calculation of spatial cam rotation angle in the equation of spatial cam contour expansion. This correction eliminates the error generated by the commonly used methods. Based on the expression of the follower’s 3D trajectory and the spatial geometry of spatial cam, this paper has deduced the planar polar curve equation for determining polar coordinates for the curve of planar expansion outline. Furthermore, this paper provides an example of spatial cam contour design based on sinusoidal acceleration variation. According to polar coordinates and the movement of curve equation function expression, this paper applies MATLAB software to solve coordinates for the cam expansion curve and use AutoCAD software to generate spatial cam expansion contour that meets the requirement of the law of motion. This method provides a design process that is simple, intuitive and easy to master and implement. It also avoids the design error in the traditional methods for generating contour of spatial cam with oscillating follower that requires high precision.However, non-equalization machining for spatial cam trough remains to be a difficult problem. This paper focuses on the analysis of running conditions and machining processes of spatial cam with oscillating follower. We point out the common errors in the biased distance cutting. By analyzing the motion of oscillating follower of spatial cam, we present a new 3D curve expansion model of spatial cam trough-outline. Based on this model, we have proposed a machining method for trochoidal milling with non-equalization diameter cutter. This new method has led to a creative and effective way for non-equalization diameter machining for spatial cam with oscillating follower.