【摘要】 本文对蜗杆凸轮式高速间歇运动机构的接触线、啮合面和凸轮曲面计算及压力角、诱导法曲率和接触部分滑动特性等作了比较全面的分析,提出了一些计算公式。特别分析了滚子两个方向的滑动情况,提出了第一曲面(已知曲面)为变速运动时的诱导法曲率计算式。最后结合一个实例给出了一套线图和啮合图形。还分析了惯性力矩大小对啮合特性的影响及一些薄弱点部位,指出惯性力矩大时,有时反而有利。本文还比较了机构的几种不同运动规律对压力角和诱导法曲率等的影响。更多还原

【Abstract】 Objective.Having the advantages of simplicity,reliability,accuracy in positioning,long service life,adaptability to different working conditions especially being moved steadily in high speed operation,the concave globoidal cams are increasingly used as the effective intermittent mechanisms in various automatic machines nowadays.In order to improve meshing performance,it is necessary to find out such meshing behaviours of this mechanism as contact line,surface of action,pressure angle,relative curvature,sliding condition and interference etc.so as to rationally choose geometrical parameters and cam curves of this mechanism.By and large,this paper offers the general rules for calculating the curved surface of concave globoidal cam and analyzing the meshing behaviours as above.Particularly,the bidirectional sliding on the surface of follower roller is analyzed.In this case,formulas for calculating the relative curvature are thus suggested if the known curved surface of cam mechanism is in accelerated motion.The effect of moment of inertia of follower and different cam curves on meshing behaviour and some weak points on the surface of action are discussed as well.Maybe the greater moment of inertia is favourable to meshing sometimes.Penally,a series of contact lines,sliding on roller surface and the theoretical and real surfaces of action are given through the medium of an example.Effects of different moments of inertia and cam curves on pressure angle and relative curvature ect.are compared (see Table 1).Fig.1 Concave globoidal cam mechanism Fig.2 Position of rollers relative to camFig.3 Relationship between rotating angles of follower ε1 and of cam ε2 Fig.4 Coordinate for the mechanism and some geometrical parameters Fig.5 Pressure angle Fig.6 Relative velocity and sliding Fig.7 Sectioning for the cam Fig.8 Contact lines of roller Fig.9 Analysis of sliding on roller surface Fig.10 Surface of actionFig.11 Cam contour,as the solution to the example in this paper Tab.1 Meshing behaviours by comparing different moments of inertia and cam curves,as a result to the example.Notes:Condition 1——moment of inertia of follower is smaller than load;Condition 2——moment of inertia of follower is greater than load;βmax——max.pressure angle(Kg)max——max.relative curvature(λs)max——max.axial sliding velocity of roller(λrd)max——max.difference of roller’s peripheral velocities;ε2——rotating angle of camx——abscissa of contact point.更多还原