共查询到20条相似文献,搜索用时 125 毫秒
1.
新型点啮合式弧面分度凸轮机构的设计与制造 总被引:6,自引:0,他引:6
线啮合式弧面分度凸轮机构由于其接触线是空间曲线而使得传动过程中凸轮与浪子产生相对滑动并产生不均匀磨损,从而影响其使用性能。本文提出了用点啮合传动来代替线啮合传动的新型点啮合式弧面分度凸轮机构,并给出了这种新型点啮合式弧面分度凸轮机构的设计原理和点啮合式空间分度凸轮的加工方法;最后指出了这种新型点啮合式弧面分度凸轮机构优良的结构特性、运动特性和广阔的开发前景. 相似文献
2.
高文光 《世界制造技术与装备市场》2009,(6):99-103
弧面分度凸轮是一种不同于普通圆柱凸轮的比较新颖的传动凸轮(图1)。在弧面分度凸轮传动机构中,弧面分度凸轮与从动分度轮垂直且不相交,弧面分度凸轮的弧面分度槽与从动分度轮上几个滚子中的一个或两个进行无间隙啮合。 相似文献
3.
4.
在圆锥滚子弧面分度凸轮机构的基础上,提出了点啮合球锥滚子弧面分度的凸轮机构。系统地分析了该机构啮合曲面的法曲率和点啮合的接触线,为研究球锥滚子弧面分度凸轮机构奠定理论基础。 相似文献
5.
弧面分度凸轮机构的运动几何特性分析 总被引:6,自引:1,他引:6
本文采用回转运动群的方法,分析了弧面分度凸轮机构的啮合原理,建立了分度凸轮的空间廓面方程,确定了啮合传动的两类界限条件及传动压力角表达式,并对此类机构的运动几何特性进行了计算机仿真分析。 相似文献
6.
7.
8.
通过对弧面分度凸轮机构中各个坐标系的建立,利用齐次坐标变换推导出弧面分度凸轮的曲面方程,并基于MATLAB对凸轮曲面进行了数值计算,再将得到的曲面数据导入三维建模软件中进行建模,并根据空间啮合理论,利用ADAMS对凸轮机构进行了动力学分析,最后应用有限元软件MARC对分度盘与凸轮啮合处进行了应力分析,得到所设计的弧面分度凸轮机构的全面分析结果,为机构优化和制造提供了重要依据. 相似文献
9.
10.
针对现有弧面凸轮廓面修形方法存在的不足,提出了一种全新的弧面凸轮廓面修形方法,并对该修形方法进行了理论分析与加工实践。采用弧面凸轮非工作面避让原则以防止分度段凹槽两侧廓面同时与滚子啮合,加厚分度停歇段凸脊以消除轴承与滚子内游隙,多滚子啮合时使压力角小的滚子优先参与啮合以提高传动效率,通过以上措施,有效地保证了孤面凸轮分度段的实际工作廓面与理论设计廓面、实际中心距与理论设计中心距的一致性,改善了弧面凸轮机构的装配性能、分度精度与传动效率,有效地消除了弧面凸轮机构可能存在的干涉现象。 相似文献
11.
柴油机配气凸轮工作环境较为恶劣,工作过程中配合界面间载荷、速度及曲率半径等工况周期性变化,导致润滑接触条件苛刻,磨损情况恶劣。以某船用柴油机配气凸轮机构典型工况为算例,针对凸轮-挺柱常见的磨损问题,研究凸轮-挺柱动态接触特性;采用余弦-等速段和高次五项式对凸轮型线进行优化设计,并对凸轮-挺柱副动态接触及弹流润滑状态进行数值分析。结果表明:原凸轮磨损的原因是凸轮-挺柱副在运动周期内动态接触应力出现明显波动,最大值超过许用应力值;经型线优化设计后,凸轮-挺柱动态接触应力降到许用值以下,改善了动态接触特性,凸轮型线具有较好的润滑特性,运行过程中可保持较稳定的油膜润滑状态;凸轮转速和接触载荷的改变会直接影响凸轮-挺柱的润滑状态,尤其是随凸轮转速增大,润滑膜厚增大,压力减小,润滑接触状态明显改善。 相似文献
12.
介绍了平行分度凸轮机构的载荷计算方法,用ANSYS/LS-DYNA的*vread命令读取由VB产生的平行分度凸轮轮廓曲线数据,建立了平行分度凸轮机构的有限元分析模型,对平行分度凸轮机构在分度期的应力进行了仿真,确定了它的最大应力状态和最大应力. 相似文献
13.
14.
15.
摆动滚子从动件盘形凸轮的自动化设计 总被引:2,自引:0,他引:2
在高精度凸轮的设计过程中,需要实现凸轮实际轮廓曲面的精确设计.解析法虽然可以精确计算出凸轮廓线上各点的坐标值,但要得到完整的凸轮实际轮廓曲面,需要手工编制复杂的程序,尤其是在摆动滚子推杆盘形凸轮的设计过程中,对于凸轮理论轮廓曲面的等距偏移曲面的编程更为复杂.因此以摆动从动件盘形凸轮机构为例,提出了利用解析法结合Pro/E软件的参数化设计功能进行凸轮实际轮廓曲面的精确自动化设计新方法.这一方法可以大幅度提高解析法设计凸轮实际轮廓曲面的效率,从而为解析法在凸轮机构设计方面的广泛应用奠定了基础. 相似文献
16.
为研究乏油条件下偏心凸轮副的润滑状态,基于凸轮-挺杆机构建立时变乏油润滑模型,探究一个周期内6个典型瞬时(60°、120°、180°、240°、300°、360°)的压力和油膜厚度变化规律,并分析不同凸轮旋转角度下转速、初始载荷和润滑油黏度等参数对接触区润滑状态的影响。结果表明:当凸轮转至180°时,膜厚最小,压力最大,乏油状况最严重;限量供油下最小膜厚出现在凸轮转角为180°时,但是凸轮转角为0°时乏油速度最快,乏油程度更深;增大凸轮旋转速度时乏油速度更快,乏油程度更深;相同供油条件下,润滑油黏度越高使得接触区乏油情况越严重,乏油速度更快,乏油程度更深;载荷对接触区的润滑状态的影响较小,只在凸轮转角为0°接触区卷吸速度最大时,能够体现出载荷对接触区润滑状态的影响。 相似文献
17.
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
18.
19.
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