Roller Follower Research Articles

Energy loss comparison between kinematically equivalent mechanisms: Slider-crank and eccentric cam

The reduction of energy consumption in industrial processes is a challenge to be confronted within the framework of the United Nations’ Sustainable Development Goals. The present study compares the energy loss per cycle of two kinematically equivalent mechanisms: a slider-crank and an eccentric cam with a translational roller follower. We use the work-energy theorem to evaluate energy losses by using a viscous friction model in a stationary regime. The innovation of this study lies in the energetic comparison to identify the best and worst alternatives by analyzing the contribution of their main geometrical parameters, such as crank length, rod-crank length ratio, roller radius and follower offset. The aim is to provide guidelines to help machinery designers to take relevant preliminary decisions that affect energy efficiency. Herein, we include analytical models, numerical simulations and experimental results using a test stand that can be adapted to other planar one degree-of-freedom mechanisms. In this context, we conclude that an eccentric cam mechanism with a big roller radius and no offset provides the best energetic efficiency among the aforementioned mechanisms.

Optimal Design and Dynamic Analysis of a Spring-Actuated Cam-Linkage Mechanism in a Vacuum Circuit Breaker

This study attempted to establish an optimal design and perform dynamic analysis for a spring-actuated cam-linkage composite mechanism in a rated 12 kV, 25 kA vacuum circuit breaker (VCB). The optimal design of the VCB mechanism involves two steps: the first step involves the optimal design of the stiffness of closing springs and the cam profile, based on three-order polynomial motion curve of the follower; the second step involves the optimal design of a four-bar linkage. To minimize the surplus work in the VCB operating mechanism, the overall difference between the general output force and general resistant force of the VCB operating mechanism during the closing operation was adopted as the objective function to be minimized. Furthermore, the differential evolution algorithm with the golden ratio (DE-gr), an efficient and accuracy metaheuristic algorithm, was employed as the optimization method. The dynamic analysis of the optimal operating mechanism was conducted using a MATLAB-coded program and verified by the multibody dynamic software MSC-ADAMS. The dynamic analysis revealed that the optimal design of the VCB mechanism can considerably decrease the average closing velocity of the movable contact and the Hertz stress between the contact surface of the cam and the roller follower.

Experimental Investigation of Frictional Power Apportionment of Moving Parts in a Hydrogen Fueled Multi-Cylinder Spark Ignition Engine

This study deals with the frictional power of each moving part in hydrogen fueled multi-cylinder spark ignition engine. The moving parts such as piston, rings, bearings, cam, and roller follower are considered for this study. The engine was run at a constant speed of 1500 rpm with different loads. The indicated power of the engine is calculated using the in-cylinder pressure data, and the brake power is measured with respect to different loads. The frictional power of each moving component is calcu-lated using the models available in the literature. The constants of the models are calibrated for the engine with the input of the measured experimental data. The frictional power of the components increases with an increase in the engine’s load. The friction between the piston and the ring with the liner is the highest among other components’ friction due to mainly gas pressure (in the piston rings) acting on the piston being the highest. The percentages of frictional power of each moving component at the power output of 15.1 kW are 30.8% (friction in piston rings due to gas pressure), 18.4% (piston skirt), 13.4 % (bearings), 8.5 % (cam), 6.9 % (piston ring tension) at applied engine load of 15.1 kW. This study results could be useful to find avenues for reducing the friction of the moving parts to enhance the fuel economy and endurance life of the engines.

Influence of Nonlinear Dynamics Behavior of the Roller Follower on the Contact Stress of Polydyne Cam Profile

The effect of the cam profile on the nonlinear dynamics phenomenon of the follower is studied at three involutes’ profiles for the cam. The value of the Lyapunov exponent parameter is calculated at different internal distances of the follower guide from inside and at different cam speeds. The effect of the Lyapunov exponent value on the contact stress is studied based on the clearance between the follower and its guides. The contact between the cam and the square grooving key and between the cam and the follower has been taken into consideration at different locations. The finite element method is used to calculate the contact stress numerically using the SolidWorks program. The nonlinear response of the follower is calculated analytically using the Newton–Euler equations of rigid body dynamics of translation and rotation motions while the follower position is tracked experimentally using a high-speed 3-D camera device. The contact stress is checked and verified using photo-elastic apparatus. The data of the contact stress against time are used in the Wolf algorithm code to extract the value of the largest Lyapunov exponent. A phase-plane diagram is drawn at different cam speeds and different internal distances of the follower guide from the inside. The periodic and non-periodic motions of the contact stress are examined at different contact locations for the follower with the cam profile. The higher the value of contact stress, the higher the value of the largest Lyapunov exponent parameter and the higher the value of bending deflection.

Grooved Cam Mechanism With a Translating Follower Having an Added Ternary-Roller Intermediate Link

Abstract The paper presents an analytical approach for designing grooved cam mechanisms with a modified arrangement of the common translating follower. That is, an intermediate link having three rollers is added between the cam and the common follower. On the basis of an existing cam mechanism with a common roller follower, an intermediate link that has three rollers is added between the cam and the common follower. Such a cam mechanism has two sets of profile and can create multiple contact points between the cam and the follower at any instant. The two sets of profiles of such a cam mechanism can serve as the grooved types. Since the follower has three rollers that can simultaneously contact the cam at any instant, it can be positively driven along the guided groove of the cam contour. The contact forces and contact stresses of such a cam mechanism are analyzed to illustrate the advantage of spreading the force transmission and reducing the contact stress of this uncommon follower. The obtained results indicate that the contact stress at the surface of the cam and the follower for such a cam mechanism can be reduced by 30 to 47% in comparison with those of the cam mechanism with a common translating roller follower. In conclusion, the cam mechanism with a translating follower having an added ternary-roller intermediate link can be a preferable choice for the applications that follower is against heavy loads or moves at high speed.

Nonlinear dynamics phenomena in globoidal cam with roller follower mechanism

• A multi degrees of freedom systems are used to suppress the spiral orbits of the nonlinear dynamics phenomena of the follower movement. • Linear and nonlinear spring-damper systems are used to suppress the nonlinear dynamics phenomena. • An OPTOTRAK/3020 with an infrared camera device is used to track the follower position experimentally. • A bifurcation diagram is used to detect the non-periodic motion of the follower movement. • Nonlinear dynamic response of the follower movement is calculated using the theory of mechanical vibration . This paper study the nonlinear dynamics phenomena in a globoidal cam and roller follower mechanism. The influence of internal dimension of the follower guide (F.G.I.D.) and cam angular speeds (N) on the nonlinear dynamics behavior are considered. Power spectrum analysis, phase-plane mapping and Largest Lyapunov exponent parameter are used to investigate the non-periodic motion of the follower. A multi degrees of freedom of (spring-damper-mass system) are used to suppress the spiral orbits of the nonlinear dynamics phenomena for the follower movement. Nonlinear dynamic response of the follower movement is calculated using the theory of mechanical vibration. Linear and nonlinear spring-damper systems are used to suppress the nonlinear dynamics phenomena. A bifurcation diagram is used to detect the non-periodic motion of the follower movement. A numerical simulation is done using SolidWorks software. An OPTOTRAK/3020 with an infrared camera device is used to track the follower position experimentally. The peak of nonlinear response of the roller follower is reduced by (20.89 % , 47.76 % , 58.2 % , 67.16 % ) after using multi degrees of freedom systems.

Non-periodic motion reduction in globoidal cam with roller follower mechanism

Non periodic motion has been investigated using power spectrum analysis of Fast Fourier Transform (FFT), Lyapunov exponent parameter using Wolf algorithm, and Phase-plane mapping. A multi degrees of freedom (spring-damper system) are added at the end of the follower stem to reduce the nonlinear dynamic behavior of the follower. In the experiment setup, data acquisition technique with signal processing approach is used through an infrared camera device to capture the nonlinear dynamic movement of the follower. A numerical simulation is done using SolidWorks software. An OPTOTRAK/3020 with an infrared camera device is used to track the follower position experimentally. The peak of nonlinear response of the roller follower is reduced by (20.89%, 47.76%, 58.2%, and 67.16%) after using multi degrees of freedom systems.

Contact Stress Distribution of a Pear Cam Profile with Roller Follower Mechanism

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.

Deflection calculation of cam profile due to a Hertzian contact pressure

AbstractThe bending deflection of cam profile was analyzed for three paths of contact and distinct Hertzian contact pressure. The impact happened between the disc cam and roller follower based on the contact parameters. The contact parameters are contact body stiffness, sliding contact velocity, exponent and penetration. A disc cam and roller follower system were discussed and analyzed for the dynamic response of the follower and bending deflection of the cam profile. The objective of this paper was to study the effect of contact load on the bending deflection. A system with spring stiffness (k) and viscous damping coefficient (c) at the end of the follower stem was used to reduce the bending deflection on the cam profile. The theory of circular plate was applied to derive the analytic solution of the bending deflection. The dynamic response of the follower had been determined by using the SolidWorks software based on the contact parameters. The experimental setup was done through an infrared camera device. Finite-element analysis was used to calculate the bending deflection of the cam profile numerically. Finite-element analysis was carried out by using the ANSYS version 19.2 package. The analytic and simulation results are checked and verified for bending deflection at the point of contact. The reduction rate for bending deflection was 73.425% for path no. (1), 85.925% for path no. (2) and 61.467% for path no. (3).

Design and analysis of a new bicontact cam mechanism

Based on an observation from a previous work, the authors use the degree of passive freedom of a mechanism with roller follower to propose a new type of mechanism. In the new mechanism, the roller is replaced by a jointed element that forms two contacts with the cam. The obtaining of the cam profile is the main disadvantage of the cam mechanisms but in the present work, by using a cam formed by two connected discs, it is aimed to be avoided. The method is illustrated by designing the mechanism in CAD software followed by the simulation of its movement. To optimize the movement of the final element, the equivalent mechanism with lower pairs is used which has the advantage that the lengths of the elements are constant. The kinematics of the final element is particularly sensitive to the variation of the dimensions of the mechanism, fact illustrated by an example.

Analytic and numerical results of a disc cam bending with a roller follower

The bending deflection of a disc cam with a roller follower was analyzed by using constant angular velocity of the cam. The objective of this paper was to study the effect of the contact load on the bending deflection of the cam profile. Numerical simulations were carried out using SolidWorks and ANSYS Ver. 19.2 package based on finite element analysis. SolidWorks was used to determine the dynamic response of the follower, while the bending deflection of the cam profile has been investigated using ANSYS package. The modal and harmonic analyses were used to find the natural frequency and the dynamic response of the bending deflection. The theory of circular plate was applied to derive the analytic solution for the bending deflection. The experiment data has been collected with an infrared camera system. The dynamic response of the follower, at the point of contact, was verified analytically and experimentally. The reduction rate for bending deflection is (73.425%) for path no. (1), (85.925%) for path no. (2), and (61.467%) for path no. (3). The harmonic amplitude peak of the point (18) on the nose (2) is bigger than the peak of the point (4) on the nose (1) because of large values for the radius of curvature of the nose (2).

Nonlinear dynamics behavior of cam-follower system using concave curvatures profile

Nonlinear dynamics behavior of the roller follower is discussed for different follower guides’ internal dimensions and cam angular speeds. A dynamic tool such as Wolf algorithm is used to extract largest Lyapunov exponent parameter. Positive value of Lyapunov exponent parameter indicates non-periodic motion and chaos. The influence of flank curvature of the cam profile on the nonlinear dynamic behavior of the roller follower is investigated. Impulse and momentum theory is used to describe the impact phenomenon based on the contact force between the follower and its guides. Contact parameters such as exponent, sliding contact velocity, contact bodies stiffness, penetration, and damping ratio are used in SolidWorks software to simulate follower movement numerically. Experiment setup has been done by taking into consideration the use of an infrared three-dimensional camera device through a high precision optical sensor. The follower motion is non-periodic when the cross-linking of phase-plane diagram diverges with no limit of spiral cycles.

Dynamic response control of swing roller follower system

This paper studied the design of Proportional-Integral-Derivative (PID) control system for the attenuation of the residual vibration in the swing roller cam-follower system designed for horizontal narrow loom. The dynamic model for the system was developed and the PID controller coefficients were synthesized to ensure that the follower and beater systems behaved in a desired manner. The controller for the system is designed and implemented on the MATLAB® and Simulink®. Basic concepts of feedback for closed-loop control regulators is used to maintain the system stability and to improve the system’s performance using the classical structure of proportional, integral, and derivative controllers. The performance of the mechanism is assessed according to the extreme residual vibration amplitude value of the working links. The variation in the gains of the derivative controller was found to have substantial influence on the reduction rate of the residual vibration of the mechanism during operation.
 Keywords: Cam, mechanism, residual, vibration, modeling, control, feedback.

Uso de las curvas de Bézier en el diseño de la ley de desplazamiento del mecanismo de leva -seguidor: Esfuerzo efectivo de Von Mises

Designing cams by BézierCurves has become increasingly common, since the mathematical development of this method is less complex. Bezier curves are Bernstein-based polynomials under a unitary domain, and in that sense, this article presents the design of a cam using Bezier curves of degrees 5, 7 and 9. And beyond, this article seeks to show the variation of the effective effort of Von Mises in a cam-follower mechanism composed of a disc cam and a roller follower with translation movement and force closure. The expressions that allow determining the variation of Von Mises' effort for each of the curves used are presented. This variation is presented by means of graphs in which it is observed that as the degree of the curve increases, the magnitude of the efforts is greater, and this increases the probability of failure in the mechanisms. In addition, it was found that there is an inverse relationship between the stress and the radius of the primary circle of the cam

Experimental and theoretical evaluation of friction in roller follower valve train

Fuel efficiency in automobiles has grown in importance greatly in past few years but it has also raised concerns about friction and durability of components in engines. The valve trains have to operate in harsh and transient operating conditions frequently promoting friction. In this paper, an innovative and effective technique based on strain gauges has been presented which is used to measure the instantaneous friction in roller follower valve train. Instrumentation, friction measurement system, test procedures and results have been explained in detail. A numerical approach based on mixed lubrication concept considering roller sliding has also been presented to predict the friction. Rise in camshaft speed resulted in reduction of friction whereas increased asperity interaction at high operating temperature yielded relatively higher friction magnitude. Predicted and measured friction in roller follower valve train has been found in good agreement.

Comparison of recent optimization algorithms for design optimization of a cam-follower mechanism

This study presents the application of seven recent meta-heuristic optimization algorithms to automate design of disk cam mechanism with translating roller follower regarding four follower motion laws. The algorithms are: salp swarm algorithm (SSA), moth–flame optimization (MFO), ant lion optimizer (ALO), multi verse optimizer (MVO), grey wolf optimizer (GWO), evaporation rate water cycle algorithm (ER-WCA), and mine blast algorithm (MBA). The optimum cam design problem is formulated with three objectives including the minimum congestion, maximum performance, and maximum strength resistance of the cam. Moreover, the effect of selecting follower motion law on the optimal design of mechanism is investigated. The computational results clearly indicate that the utilized algorithms are very competitive in structural design optimization, especially MBA, ER-WCA, MFO and GWO techniques. Among the four follower motion laws, the polynomial 3-4-5 degree is the best one.

Roller sliding in engine valve train: Effect of oil film thickness considering lubricant composition

In roller follower valve train, proper rolling of roller reduces the chances of fatigue failure and power losses. During engine operation, the roller does slip on the camshaft surface. The oil film thickness plays an important role on the roller sliding which necessitates experimental investigations.A modern gasoline engine valve train has been instrumented using advanced sensors for real time measurement of oil film thickness and roller slip, simultaneously. Rise in oil film thickness at cam/roller interface increased the tendency of roller slip. Drag due to shear of lubricant and rise in contact loading at very high camshaft speeds resulted in reduction of roller sliding. Presence of anti-wear agents and friction modifiers increased the tendency of roller sliding.

Track-based analysis for profile generation on globoidal cam in automatic tool changer of CNC machining center

PurposeThis paper aims to propose an elementary approach towards the measurement of a globoidal cam profile used in an automatic tool changer (ATC) of computer numerical control (CNC) machines.Design/methodology/approachA simple and unique online method has been designed for the profile metrology of the cam. This simple methodology will replace the traditional methodology of profile metrology of cam by coordinate measuring machine (CMM). A globoidal cam with an indexable turret and roller follower (rotating in an enclosed track) has been evaluated in our analysis. This analysis plays a significant role in the performance determination of the cam as well as the ATC of CNC machines.FindingsA novel model has been designed and implemented to investigate the profile of a globoidal cam. The proposed methodology becomes an enhancement over the old methodology, i.e. measurement through CMM. Theoretical analysis and practical implementation prove the significance of the method.Originality/valueAn enhanced methodology to effectively measure the globoidal cam profile has been proposed. The practical implication of the proposed methodology remains for the CNC machine tool and ATC manufacturers. Finally, analytical explorations have been carried out to prove the validity of the proposal.

Optimum design of cam-roller follower mechanism using a new evolutionary algorithm

The optimum design of a cam mechanism is a very interesting problem in the contact mechanics today, due to the alternative industrial applications as a mechanism of precision. In this paper, a new evolutionary algorithm called modified adaptive differential evolution (MADE) is introduced for multi-objective optimization of a cam mechanism with offset translating roller follower. The optimization procedure is investigated for three objectives among them minimum congestion, maximum efficiency, and maximum strength resistance of the cam. To enhance the design quality of the mechanism in the optimization process, more geometric parameters and more design constraints are included in the problem formulation. In order to validate the developed algorithm, three engineering design problems are solved. The simulation results for the tested problems indicate the effectiveness and the robustness of the proposed algorithm compared to the various existed optimization methods. Finally, the optimal results obtained for the case study example provide very useful decisions for a cam mechanism synthesis.

The influence of stick–slip transitions in mixed-friction predictions of heavily loaded cam–roller contacts

A load-sharing-based mixed lubrication model, applicable to cam–roller contacts, is developed. Roller slippage is taken into account by means of a roller friction model. Roughness effects in the dry asperity contact component of the mixed lubrication model are taken into account by measuring the real surface topography. The proportion of normal and tangential load due to asperity interaction is obtained from a dry contact stick–slip solver. Lubrication conditions in a cam–roller follower unit, as part of the fuel injection equipment in a heavy-duty diesel engine, are analyzed. Main findings are that stick–slip transitions (or variable asperity contact friction coefficient) are of crucial importance in regions of the cam where the acting contact forces are very high. The contact forces are directly related to the sliding velocity/roller slippage at the cam–roller contact and thus also to the static friction mechanism of asperity interactions. Assuming a constant asperity contact friction coefficient (or assuming that gross sliding has already occurred) in highly loaded regions may lead to large overestimation in the minimal required cam–roller contact friction coefficient in order to keep the roller rolling. The importance of including stick–slip transitions into the mixed lubrication model for the cam–roller contact is amplified with decreasing cam rotational velocity.