共查询到20条相似文献,搜索用时 31 毫秒
1.
2.
3.
The problem of this paper is the high contact stress at the point of contact between the cam and the follower.A pear cam and roller follower mechanism were studied and analyzed for different position of the follower and different contact compression load.The objective of this paper is to study the effect of contact compression load on the contact stress distribution of the cam profile at the point of contact.Four different positions of the follower with the cam was considered(0°,90°,180°,and 270°).The theory of circular plate was applied to derive the analytic solution of the contact stress.The numerical simulation had been done using ANSYS Ver.19.2 package to determine the contact stress,while SolidWorks software was used to investigate follower displacement,velocity,and acceleration.Four distinct values of the compression contact load,such as 3.121 N,6.242 N,9.364 N,and 12.485 N,were used in the numerical simulation.In the experiment setup,a photo-elastic technique was carried out in the field of polarized light to exhibit the stress distribution on the cam specimen.The annealed PSM-4 backalate material was used in the experiment setup.The experimental value of contact stress was checked and verified analytically and numerically at the point of contact.The innovation in this paper the use of spring-damper system which reduce the value of contact stress at the point of contact.The contact stress was maximum 2.136 MPa when the follower located at 270° with the cam,while the contact stress was minimum 1.802 MPa when the follower located at 180°at compression load 12.485 N. 相似文献
4.
5.
设计平面凸轮轮廓的新方法 总被引:10,自引:0,他引:10
提出了设计平面凸轮轮廓的相对运动法,这是一种适用于各种平面凸轮轮廓设计的通用方法。利用从动件相对凸轮运动的相对速度、相对加速度和从动件的表面法线确定平面凸轮的轮廓方程、压力角和曲率半径是该方法的基本原理。通过建立基于反转原理的通用模型、坐标系和齐次坐标变换技术,导出了平面凸轮的轮廓方程、压力角和曲率半径的一般表达式。该推导过程不仅适用于手工完成,而且为平面凸轮轮廓设计的智能化、自动化打下了基础。根据设计的自动推导和求解策略,用C++和OpenGL语言开发了计算机辅助设计程序实现了平面凸轮轮廓设计和机构运动仿真的自动化。最后,给出了设计和仿真实例。 相似文献
6.
利用高副低代法导出直动从动件盘形凸轮廓线上任意点曲率半径的公式 ,该公式不仅先于凸轮廓线方程求出廓线的曲率半径 ,还显示了曲率半径和压力角之间的内在联系 ,从而直接把强度条件和传力性能结合起来考虑 ,有利于简化该种凸轮机构的优化设计。 相似文献
7.
8.
9.
10.
设计盘形凸轮廓线的相对速度法 总被引:1,自引:0,他引:1
提出了一种利用凸轮与从动件的相对速度设计盘形凸轮轮廓的新方法,该方法基于从动件和支承绕凸轮轴线反转的原理,利用从动件上的接触线或者滚子轴线相对固定凸轮的速度和凸轮与从动件的几何关系设计盘 形凸轮轮廓,应用该方法导出了四种不同类型凸轮机构的凸轮廓线的解析表达式,并给出了对应的设计实例。 相似文献
11.
关于按许用压力角设计最小尺寸的摆动从动杆平面凸轮机构的课题,至今未获得圆满解决。作者按微分几何的包络原理导出限制这种凸轮最小尺寸的界线方程式,据此可在电子计算机上图象显示凸轮轴心的容许区域或者直接计算其最小基圆半径和摆杆长度。文中将这种方法应用于锁合凸轮、槽道凸轮及共轭凸轮。 相似文献
12.
将"支撑线"、"支撑函数"等概念向新型凸轮机构做引伸和推广,得到了凸轮轮廓曲率半径、外凸判据、参数方程、周长和面积等一整套通用计算公式,将"支撑函数法"发展成为平底/负半径滚子从动件盘形凸轮机构共享的研究框架. 相似文献
13.
This study presents design nomograms which make it easy for the cam designer to estimate the limiting value of the investigated parameter which can be applied to a plate cam follower system, as long as the maximum contact stress between the cam and follower during both rise and return strokes of cam revolution can be determined. The undesirable phenomena of the undercutting of cam profile and the separation between the cam and the follower are taken into consideration. Moreover, these design nomograms give correlations between the investigated parameters and the optimum plate cam size and also are used to study the influence of an investigated parameter on this size. The optimum plate cam size is the combination of cam base circle radius and the amount of cam follower offset, and satisfies the suggested design procedure which is based on taking the contact stress as a design criterion. The investigated parameters are dynamic, kinematic, geometric and material. A brief discussion on using the suggested design procedure to design the size of plate cam is described. For a numerical example, the presented design nomograms are for reciprocating cam-roller-follower which operated by parabolic plate cam. 相似文献
14.
15.
Ettore Pennestri Roberto Stefanelli Pier Paolo Valentini Leonardo Vita 谷雨 《传动技术(上海)》2010,24(4):28-37
本文研究自动齿轮箱凸轮作动器的效率和磨损,着重于接触动力学。采用罚函数方法仿真凸轮和从动杆间接触,该模型基于有限元与连续弹性基础梁理论近似。采用Hertz理论考虑凸轮和从动杆间相对运动时主要曲率的变化计算基础模量。为比较接触力和不同凸轮轮廓的磨损,该模型仿真概括了整个档位。 相似文献
16.
本文将直动从动件圆柱凸轮、蜗杆凸轮等归为一类,用共轭曲线原理导出了它们的精确的啮合计算公式,如压力角、凸轮工作曲面方程、相对速度、沿接触线法线方向的诱导法曲率等。这些公式为提高这类凸轮的设计质量,建立它们的CAD系统提供了基础。 相似文献
17.
针对平底从动件盘形凸轮机构,导出了同时适用于直动和摆动从动件的凸轮廓线综合公式及凸轮实廓外凸的条件式。 相似文献
18.
应用支撑函数法,推导了两种型式的作平面复杂运动平底从动件盘形凸轮机构凸轮廓线的曲率半径、外凸性判据、参数方程、周长及凸轮面积的通用计算公式。 相似文献
19.
20.
Siyoul Jang 《Journal of Mechanical Science and Technology》2008,22(5):946-956
The contact behavior between cam and follower is greatly influenced by the kinematics and dynamics of the whole valve train
system. This is the reason that both shape and thickness of the fluid film in the contact gap are mainly determined by applied
loads and relative contact speeds as well as the curvatures of contacting elements. Most of the studies about lubricant film
behavior between cam and follower have been performed without a consideration of transient effects in the contact gap. For
the computational difficulties of transient effects, most contact conditions such as relative contacting speeds have been
regarded as quasi-steady state during the whole operating cycle.
In this work, in order to obtain stable convergence, a multigrid multi-level method is used for the computation of load capacity
in the lubricant film. Nonlinear valve spring dynamics are also considered in the same way as Hanachi’s. From the computational
results, transient EHL film thicknesses under the conditions of different contact geometries are computed for a pushrod type
valve train system during an engine cycle. Several results show the squeeze film effect, which is generally not found with
conventional EHL computations of the cam and follower contact. The results are also compared with those by the Dowson-Hamrock
(D-H) formula, which does not consider the dynamic film effect. Without the dynamic film effect as in D-H’s formula, the minimum
film thickness is highly dependent on the entraining lubricant velocity, whereas the minimum film thickness including the
squeeze film effect is dependent on the applied load. 相似文献