负半径滚子直动推杆盘形凸轮机构运动保真及其解域研究OA

The issue of"undercutting"in mechanisms with negative radius follower was highly prone to occur and was very prominent.By discovering the offset curve with opposite direction relationship be-tween the cam pitch curve and cam profile,a new criterion was proposed for no-undercutting based on cam pitch curve.Based on this new criterion,the issue of undercutting was conducted in-depth research.Firstly,a coordinate system was established based on the base circle radius and eccentric offset,and the discrete-traversal method was employed.The inevitable/possible undercutting regions were discovered.The new concepts of non-roller-type/roller-type undercutting were proposed.And the impact of stroke,rise/return phase motion angle,and motion law on inevitable undercutting regions were discussed.Sec-ondly,a vertical numerical axis was established based on roller radius to analyze the distribution characteris-tics of two types of roller radius values.Then,based on the three-dimensional coordinate system estab-lished with the base circle radius,eccentric offset,and roller radius,the solution space and two types of non-solution spaces were obtained for ensuring no-undercutting.Two types of cam profile morphological characteristics,specifically the"swallowtail-shaped-type Ⅰ/type Ⅱ"corresponding to the two types of non-solution spaces were analyzed.This solution space expresses the range of values for the base circle ra-dius,eccentric offset,and roller radius that satisfied the no-undercutting conditions,as well as the mini-mum size of the cam profile,etc.Finally,the correctness and effectiveness of the proposed theory and method were verified through design cases.