Cam Profile Design Research Articles

A unified analytical disk cam profile generation methodology using the Instantaneous Center of Rotation for educational purpose

Cam design is a fundamental part of the Mechanism and Machine Theory (MMT) and is included in the vast majority of MMT books. Cam profile design is usually determined with graphical and analytical methods. Graphical methods are didactically very successful to introduce the theory of cam profile generation in a simple way. In turn, analytical methods allow computer implementations of cam profile generation in order to reproduce it accurately. Most modern MMT books describe analytical methods using geometric equations and envelope theory. However, the analytical profile definition depends on the specific type of follower and there is a lack of a general formulation. This work presents a unified and general analytical formulation for the disk cam profile determination. Based on the Instantaneous Center of Rotation and the kinematic inversion, the formulation provides analytical expressions of the cam profile and is applicable to any type of follower. Thus, the unified formulation can be used in forthcoming books on this discipline.

Cam Profile Design of Low-Speed Marine Diesel Engine Based on the Grey Theory

The camshaft profile is one of the important parameters of the engine, the reasonableness or otherwise of its design directly influences the engine’s power output, fuel consumption, emissions, noise and reliability. However, most existing cam profile optimization designs are based on the basic software operation, profile parameter selection and tuning lack a scientific theoretical basis. In order to address this issue, this study establishes a single valve kinematic model of the gas delivery mechanism of diesel engines by using the AVL-EXCITE Timing Drive, and performs a model-based multinomial kinematic acceleration cam profile design. Subsequently, an orthogonal design method is employed to obtain the parameter combinations that can satisfy the dynamic requirements. The research investigates the influence of cam profile design parameters (C 4, p, q, r, and s) on valve fullness, maximum jerk, cam contact stress, and valve seating force through a systematic study. Lastly, based on the grey correlation theory, a thorough analysis of the performance indices of cams with different profile parameter combinations is conducted. The optimization problem of the profile parameters with multiple performance indicators is transformed into a single-objective grey relational optimization problem, resulting in the optimal cam profile parameter combination of C4 =0.1, p=14, q=20, r=28 and s=36. The optimal method proposed in the paper is straightforward to implement and is applicable to the optimum design of cam profiles of the engine, which is of great importance for the optimal design of cam fabrication processes.

Investigation of the effect of camshaft profiles designed with the circular arc curve method for a common rail dual fuel engine on mechanical vibration and noise emissions

In this study, the design and manufacturing of cam profiles with different valve lifts were carried out using the geometric spring curve method for a single-cylinder, four-stroke common rail diesel engine. Subsequently, the impact of the designed cam profiles on vibration and noise emissions in conventional diesel combustion was examined. The effects of the cam profiles obtained using the circular spring curve method and fitted with Fourier series on the tappet's speed, acceleration, and leap were examined, and then the cam profiles to be manufactured were determined. Experimental tests were conducted on vibration and noise emissions using the manufactured cam profiles with pure diesel fuel at five different engine loads and a constant engine speed. When the results are examined, increasing the valve lift amount compared to the original cam resulted in an approximate 24% increase in vibration level, while decreasing the valve lift amount reduced the vibration level by approximately 20%. the effect of cam profile modification on average noise emissions was quite evident.

The Design of the Controlling Cam Optimization Profile in an Automated-Cutoff Valve Based on Ga

In order to achieve the controlling performance of automated-cutoff valve, an optimization method of cam profile design is indicated based on GA. The selection conditions in the algorithm are established according to the analysis of mechanical structure after the other parameters are specified. The effectiveness of the optimization algorithm is improved in the sequent test.

Compact Variable Gravity Compensation Mechanism With a Geometrically Optimized Lever for Maximizing Variable Ratio of Torque Generation

In this article, we propose a compact variable gravity compensation (CVGC) mechanism with a geometrically optimized lever shape. The CVGC mechanism can be used to generate gravity compensation torque by employing a cam and lever mechanism and can also amplify the gravity compensation torque by varying the pivot point of the lever. Among these advantages, we aimed to maximize the variable ratio of torque generation with an optimized lever. First, the mechanism concept and details of the CVGC mechanism are explained. Next, the conceptual benefit of using a curved lever instead of the original lever is explained. Afterward, the modeling and mechanics of the testbed using a curved lever are presented for force analysis. Based on these mechanics and B-spline curve representation, the methodology for optimizing the curved lever and cam profile design is presented. Finally, the performance of variable gravity compensation using the optimized lever is verified through experiments that compare the designed and measured gravity compensation torque. As we had hoped, the verification test shows that using the optimized curved lever improves the variable ratio from 5.27 to 14.43.

Research on Angle-area Value of Engine Valve Based on MATLAB

The capacities of engine intake and exhaust are directly affected by the passage ability of the space between valve and seat ring and the area of the throat section. The angle-area value is a reasonable parameter to evaluate this capability. In this paper, using MATLAB software to calculate angle-area value of Engine valve. Analyzing the influences of value phase Angle, valve diameter and valve lift on intake angle-area value to explore some rules of influence. Meanwhile, based on analysis of some problems in the design of engine valve lift height and profile, some optimal design ideas are put forward, which can provide some references for the design of engine CAM profile

Dimensionless design approach to translating flat faced follower mechanism with two-circular-arc cam

Abstract. In this study, a dimensionless design approach was presented for translating flat-faced follower mechanism with two-circular-arc cam. Instead of second arc radius (r2), maximum follower lift (smax) and angle of the cam rotation angle (2θmax) variables from the cam profile design parameters were made dimensionless using r2∕r (=λ), smax∕r (=ψ) and θmax∕π (=μ) respectively. Equations for cam profile and follower movement were derived and graphics were obtained depending on the dimensionless parameters. λ and ψ should be in the range [0.0, 1.0], but μ should be in the range [0.0, 0.5]. λ and ψ were changed in the range [0.10, 0.90] and μ in the [0.25, 0.45] range and λ, ψ and μ values were determined for the cam profile. Maximum velocity (vmax), maximum absolute acceleration (amax) and average follower lift (save) changes, which are one of the critical characteristics of follower, were examined for possible cam profiles according to the change of λ, ψ and μ. As a result, vmax and save decreased when μ was increased, vmax and save increased and amax decreased when ψ was increased, amax and save increased when λ was increased.

Discussed on mechanism of production and improvement for Noise and Vibration of Hydraulic valve system

Based on mechanism of production for Noise and Vibration, in this paper, analysis model is established, and improvement measure is purposed through some factors, then is tested. The results are evaluated and shown: noise and vibration of hydraulic valve system are effectively reduced by enhancing design of cam profile, choosing appropriate lubrication oil and adjusting structure parameters.

Numerical cam profile design with tappet constant speed section in internal combustion engine valve gear and fuel system

In modern internal combustion engines the drive of valves of the mechanism of gas distribution and a plunger of the fuel pump of high pressure is carried out by the cam mechanism. The functional requirement imposed to gas distribution mechanism cams is receiving the greatest valve “time-section” when ensuring working capacity and reliability of the valvate drive. One of the main directions of improvement of fuel pumps of high pressure of diesel engines is increase in the maximum pressure of injection. In this work it is offered to improve a numerical method by imposition of the restriction on the first derivative of movement of the pusher on a cam angle of rotation, that is a pusher speed analog. This restriction allows to receive a cam with the site of constant maximum speed of the pusher. It allows to increase the maximum pressure of injection.

Improving cam profile design optimization based on classical splines and dynamic model

Cam profiles play an important part in the performance of cam mechanisms. Syntheses of cam profile designs and dynamics of cam designs are studied at first. Then, a cam profile design optimization model based on the six order classical spline and single DOF (degree of freedom) dynamic model of single-dwell cam mechanisms is developed. And dynamic constraints such as jumps and vibrations of followers are considered. This optimization model, with many advantages such as universalities of applications, conveniences to operations and good performances in improving kinematic and dynamic properties of cam mechanisms, is good except for the discontinuity of jerks at the end knots of cam profiles which will cause vibrations of cam systems. However, the optimization is improved by combining the six order classical spline with general polynomial spline which is the so-called “trade-offs”. Finally, improved optimization is proven to have a better performance in designing cam profiles.

Methodology to parametric design of cam profile for electronic unit pump

As to the fuel injection system of electronic unit pump, of which fuel supply principles mainly be influenced by fuel supply camshaft. Due to the requirements of the diesel engine for the fuel supply system, a new method is presented to design the constant pressure injection fuel supply cam profile. First, design principles of the fuel supply camshaft profile according to the diesel engine combustion requirement are proposed and then the parametric equation for the camshaft profile can be obtained by the proposed principles which are analyzed through math method. At last, after the prediction and comparison of the designed camshaft profile, the conclusion shows that the fuel injection system designed by the proposed principle can satisfy the injection requirements of the diesel engine. Meanwhile, the parametric equations simplify the design process of camshaft profile so as to improve the reliability and the injection performance of the fuel supply system.

Mathematical modeling and optimization of cam mechanism in delivery system of an offset press

This paper presents a new method for cam profile design and optimization by integrating a single objective optimization procedure with a dynamic model of cam-follower mechanism in delivery system of an offset press. The proposed approach based on a new strategy mainly includes two parts, a single objective optimization procedure for the kinematic characteristics of the follower and a dynamic model for the cam-follower mechanism. For the first part, the follower acceleration profile is described by modified trapezoidal curve, thereby deriving the velocity, jerk and displacement functions, respectively. Then sequential quadratic programming (SQP), which deals well with equality and inequality constrains, is adopted as the single objective optimized algorithm in this part. In the second part, a two degrees of freedom lumped parameter model taking into account the torsional flexibility and damping of the grippers, the contact compliance at the cam/roller and grippers/block interfaces, is established to investigate the dynamic behavior of the force-closed cam-follower mechanism. In order to improve the kinematic and dynamic characteristics of cam-follower mechanism synthetically, an optimization cycle, known as iterative process, is introduced to implement the procedure of single objective optimization and dynamic simulation alternately. The example illustrated in this paper, sufficiently demonstrates the effectiveness of the new method. Ultimately, the proposed approach gives cam designers a useful tool to design and optimize the cam profile, so as to reduce residual vibration.

Optimal Design of Grooved Cam Profile Using Non-uniform Rational B-splines

In order to reduce the fatigue damage in grooved cam mechanisms, grooved cam profile was reconstructed with non-uniform rational B-splines (NURBS). Considering joint friction, dynamic model of grooved cam mechanisms was established and the contact stress between grooved cam and follower was calculated using Hertz contact theory. Taking the minimum contact stress and the minimum acceleration as optimal objectives, integrated design model for respective kinematic and dynamic design approaches was set up. The integrated design mode was optimized to search Pareto-optimal solution by an improved artificial fish swarm algorithm, and optimized NURBS profile for grooved cam was acquired. The results show NURBS profile has better kinematic and dynamic performances. The impacts on grooved cam mechanism are reduced and wear characteristics are improved.

DESIGN OF A PITCH-ROLL JOYSTICK BASED ON A THREE-LOBE SPHERICAL CAM MECHANISM

A pitch-roll joystick based on a spherical cam mechanism is proposed that can be implemented as a haptics device. Spherical cams can replace the bevel gears that are conventionally used in transmission mechanisms involving shafts with intersecting axes to achieve lower backlash, lower frictional losses and higher stiffness. Such a spherical cam mechanism is essentially composed of multi-lobe-cams and conical rollers. Undercutting is a deterrent to the generation of smooth cam surfaces, which calls for the synthesis of a singularity-free spherical cam profile. The issues of high pressure angle and high contact ratio are addressed by means of a multilobe cam. The design of the cam profile and the assembly of the joystick are described. The criteria for the selection of the numbers of lobes and rollers are also explained.

Green Manufacturing Environment of Straw Packaging Container Extrusion Mechanism Design

According to the sustainable development of green packaging design, research and application of green manufacturing technology and process of plant straw packaging extrusion mechanism design. Based on the straw packaging container material formulation and molding process, the analysis of the forming mechanism of plant straw packaging container. Key components of straw packaging container extruder extrusion mechanism carry on the design. The key component of extrusion mechanism of CAM profile design, to reduce the impact vibration as the goal, set up the CAM squeezing the motion analysis of the process, all parts of the CAM profile equation is given.

Design of high-speed cam profiles for vibration reduction using command smoothing technique

Unwanted vibration in cam-follower systems causes increased forces, noise, wear, and operating costs. This paper proposes a novel method to design high-speed cam profiles for vibration reduction by using command smoothing technique. Using system natural frequency and damping ratio, the technique reduces vibrations by intelligently smoothing any basic profiles. Furthermore, an example is given to express the design process and to verify the effectiveness of the method. The displacement, velocity, acceleration, and jerk properties of the proposed profile are demonstrated to show the excellent smoothness, which benefits high-speed cam follower systems. The comparisons of vibration properties between the smoothed profile and 3-4-5 polynomial profile are explored and quantified. The smoothed profile will induce zero vibration at the design operating speed and produce a low level of vibration around it. Experimental results obtained from a rectilinear control plant validate the simulated dynamic behavior and the effectiveness of the profile created by using command smoothing.

Valve Cam Design Using Numerical Step-by-Step Method

This article studies the numerical step-by-step method of cam profile design. The results of the study are used for designing the internal combustion engine valve gear. This method allows to profile the peak efficiency of cams in view of many restrictions, connected with valve gear serviceability and reliability.

IMPROVEMENT IN MOTION CHARACTERISTICS OF CAM-FOLLOWER SYSTEMS USING NURBS

Absrtact. This paper proposes an integrated system for improving the cam-follower performance. The design method is to improve the motion characteristics of a cam follower-system. Improvement of the motion characteristics is to achieve low maximum velocity and acceleration for each follower motion curve so that jerk is minimum. Representing basic follower motion curves with nonuniform rational B-splines (NURBS) can do this. Conventional methods in designing and manufacturing of cam are tedious and time consuming. Even programming them on a computer numerical control (CNC) machine can be a difficult job because of the complexity of the cam profiles. . A CAD/CAM system is developed, which provides useful design information such as graphical and numerical representation of displacement, velocity, acceleration, jerk, pressure angle and cam profiles for both basic curves and NURBS. An analysis can be carried out based on maximum velocities and accelerations to select the best cam follower motion. It also provides cam profile coordinates for basic curves and NURBS to manufacture a cam on CNC machines. . A plate-cam is a disc-cam, which is cut out of a piece of flat metal or plate and used to transform a rotary motion into a translating or oscillating motion to its follower. Applications of these cams found in packaging machines, wire-forming machines, internal combustion engines, mechanical and electronic computers. Requirements for high performance of such machinery demand efficient methods for the design and manufacture of cams. The purpose of this paper is to develop a seamless integration of design and manufacturing of plate cams. NURBS have been used to design and optimization of cam profiles. The design parameters will be used in the manufacturing module that generates the NC program required for the machining of the designed cam.

Design of the Disc Cam Profile with Negative Radius Translating Roller Follower

Abstract: This paper is to study the force-locking and shape-locking conjugate cam mechanisms. problems of the theoretical and actual contour of the cams with negative radius translation roller follower are solved by the use of "definite proportion and division point" method. The results could lead an important foundation for further research of the new type cam mechanisms.

Valve Cam Profile Design of High-Speed Diesel Engine Based on MATLAB

Through MATLAB programming, the parameters of valve cam profile will be selected and calculated. The general design principles and methods for higher-degree polynomial asymmetrical cam profile will be introduced, improved design and experimental verification have been conducted to the cam profile of 4C18 diesel engine, and significant result has been obtained. The result shows that the higher-degree polynomial asymmetrical cam profile can effectively improve the dynamic property of valve cam and the economy, emission and dynamic property of the high-speed working section of the engine.