Use of Bézier curves in the design of the displacement law of the cam-follower mechanism: Von Mises effective Stress

Peñaloza, Carlos Humberto Acevedo; Ramón-Ramón, Sergio Andrés; Bustos-Urbano, Víctor Jhoel

doi:10.18273/revuin.v19n4-2020002

Cited by 3 publications

(2 citation statements)

References 14 publications

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“…Hultqvist et al 18 examined the effects of lubricant compressibility-pressure behavior on film thickness, pressure, and subsurface stress using a finite line-contact EHL model. Acevedo-Penaloza et al 19 studied the variations of von Mises stress in disc cams and roller followers, observing that greater forces led to a higher likelihood of failure. Additionally, they noted an inverse relationship between stress and the cam circle radius.…”

Section: Introductionmentioning

confidence: 99%

Modeling and analysis of 3D mixed lubrication in marine cam–tappet pair

Hua,

Shi,

Sun

et al. 2024

Proceedings of the Institution of Mechanical Engineers, Part J:

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During the operation of the marine cam–tappet pair, affected by periodic dynamic load, transient velocity, and micromorphology, it usually operates in a mixed lubrication state. Under extreme operational conditions, contact is likely to occur at the asperity of the interface, leading to problems such as stress concentration and dry contact. Considering the transient dynamics and three-dimensional roughness of cam–tappet pair, a mixed-elastohydrodynamic lubrication model is developed in this article, while the effects of surface waviness on the lubrication state are also investigated. The results show that the film thickness can be increased by 0.098 μm, and the coefficient of friction can be reduced by 10.6% when the wavelength ratio ranges from 1/6 to 6. However, when the amplitude exceeds 0.6 μm, the coefficient of friction may reach 0.10. Under conditions of low speed and high load, the film thickness decreases and contact load ratio increases. And about 30% reduction in film thickness is achieved on cam–tappet pair, potentially leading to increased wear or scuffing failure.

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Section: Introductionmentioning

confidence: 99%

Modeling and analysis of 3D mixed lubrication in marine cam–tappet pair

Hua,

Shi,

Sun

et al. 2024

Proceedings of the Institution of Mechanical Engineers, Part J:

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“…34 Bezier curves of degrees 5, 7, and 9 were used by Acevedo, to design a cam for seeking the practical use of Von Mises in a cam mechanism. 35 According to the known prior art, the studies about using non-uniform input motions as cam’s input are rarely about multi-objective optimization functions.…”

Section: Introductionmentioning

confidence: 99%

Study on the effect of curvature radius sudden change on mechanism characteristics for the constant-breadth two circular-arc cam mechanism with an inclined flat-faced follower

Wang

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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A two circular-arc cam mechanism is a special kind of constant-breadth cam. At the junction point of each cam contour, a mutation of the curvature radius may be produced, which affects the motion performance of the mechanism, especially its jerk performance at high speed. Based on a proposed motion model, the follower movements of the constant-breadth two circular-arc cam mechanism with an inclined flat-faced follower are analyzed. Bezier Curve is proposed to fit the driving law of the cam mechanism, while variable speed law is adopted to drive the cam mechanism motion, thus reducing motion characteristic value (AV)max (i.e., the maximum value of the velocity multiplied by acceleration for the follower’s motion law of the cam mechanism at the same motion time point) and the jerk of the follower. In this paper, the establishment of the optimization objective functions and constraint conditions, and the control node selections of the cam drive function are researched. The optimization results are obtained by using the primary objective method. The results of a test case calculation and simulation show that, the optimized drive function, according to the variable motor speed, can significantly reduce the value of (AV)max of the follower, while the jerks of the follower system are also reduced considerably. More precisely, the (AV)max value is reduced by 11.63% and the jerks are reduced on average by 15.35%, at the three jerk positions. The proposed methods provide a new approach to improving the kinematic performance of similar cam mechanisms.

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