The paper deals with a configuration of a cam mechanism with a flat follower. Friction may be reduced at the point of contact with the valve stem by a roller cam follower. The objective of this paper is to modelling design and analysis of a cam and follower. The cam and the follower have a line contact and constitute a higher pair. This force affects the stiffness, damping coefficient and also try to deform the structure. Pdf analytic analysis of a cam mechanism researchgate. They are based on either needle or cylindrical roller bearings. Analysis and simulation of cam follower mechanism using polynomial cam profile tushar kirana and s.
The cam followers force capacity assumes it operates in a perfect environment. Pdf cam mechanisms are integral parts of many products. Although the friction at the cam follower interface is usually dominant in valvetrain friction especially for the flatfaced followers, the friction from the rocker arm bearing, the camshaft bearings, and the follower valve guides also plays an important role. The flatfaced follower has been used with polydyne cam profile. Solved problems based on cam profiles engineering tutorials. Tushar kiran et al analysis and simulation of cam follower mechanism using polynomial cam profile 214 int. The driver is called the cam and the driven member is called the follower.
In practice the cam size is determined by considering two factors. The mechanism of cam and follower is essential in the engineering field and has many different functions to the different machines. Cam and follower systems are used in many common applications such as pumps and in the camshaft of an engine. The model is created by the basic needs of an engine with the available background such as forces acting over the cam by means of valve while running at maximum speed.
In a cam follower pair, the cam normally rotates while the follower may translate or oscillate. The size and the course of force of spring and also the course of force of pin are shown in figure 10 and figure 11 4. Dynamic analysis of high speed cam follower system using. The dynamic force analysis determines the cam contact forces and. Coulomb friction forces due to relative sliding motion is also. Displacement, velocity, acceleration, inertia force, spring force, resultant force, shaft torque. Adjust the cam profile using matlab to vary the valve lift. The follower arm swings or oscillates in a circular arc with respect to the follower pivot. Chironis, mechanisms and mechanical devices, mcgrawhill, new york, 2001 2. It also obtains critical design output parameters of roller cams. Pdf cam and follower are widely used in regulating, opening and. Here we are presenting some solved problems based on cam profiles.
In the cam follower with seals, a special thrust washer is employed for the sliding surface inside the bearing to improve heatseizure resistance. Note that as long as the force between cam and shoe is 0 in the force closed system the cam and follower remain in contact. An optimum design of cam mechanisms with roller follower for. A cam is a mechanical device used to transmit motion to a follower by direct contact. A familiar example is the camshaft of an automobile engine, where the cams drive the push. Starr department of mechanical engineering the university of new mexico 1 introduction adams automated dynamic analysis of mechanical systems is a cad package for mechanical system analysis and design. Cam design calculation of torque required by cam shaft. Impact forces impact is often called mechanical shock referring to an extreme abruptly applied force 10. The continuous contact between the follower and the cam is achieved by the downward forces of the spring and follower weight. Feb 03, 2016 however, a roller follower can possibly jam during steep cam displacements. This is done by using a rocker arm ratio of approximately 1. The mechanism for cam and the mechanism for follower depend upon each other so that the main mechanism of cam and follower. This type of follower can be used with a steep cam motion and does not jam. An awesome book containing many great mechanism ideas is n.
This pushes the rocker arm up and down about the pin or rocker shaft. Luckily, suppliers of cam follower bearings list each cam followers capacity as a force rather than a stress. Norton, design of machinery introduction to cam design. If m is the effective mass of the follower, then the driving.
It shows how they convert rotary to linear motion, and helps students understand their limits of use before the onset of bounce. The paper presents an original method to determine the efficiency of a mechanism with cam and follower. Notice that in all the positions, the surface of the follower must be tangent to the cam profile. Cam analysis machine tm1021 theory of machines tecquipment. A dynamic analysis is formulated in order to calculate the input torque and the followercam contact forces. Instead of an inner ring, they have a threaded solid stud pin. Cam and follower design basics design of cam profiles. Force, torque, pressure angle, curvature, contact force and shear stress. The force that presses the follower to the cam s su rface will be determined based on. Labyrinth sealing also ensures maintenancefree operation. The variables you wish to graph are accessible directly from the 3d model view. To find out the cam and follower behavior at different.
If you are designing cam follower mechanisms, your can intuitively connect the cam to the graphing function using graphic functionblocks. The curvature of the cam profile decreases sharp curves 3. Tappet bore valveguide 0 10 20 30 40 50 60 70 80 friction power w 3000 5000 6000 6500 7000 7500 engine speed rpm rff friction composition left bearing right bearing cam follower hydr. Cam shaft torque normal force of cam follower on cam distance from cam shaft center to point of contact between cam and cam follower tanpressure angle however, i am still confused about this. Project background cam is an element of the cam follower mechanical system. Although the friction at the camfollower interface is usually dominant in valvetrain friction especially for the flatfaced followers, the friction from the rocker arm bearing, the camshaft bearings, and the followervalve guides also plays an important role.
Analysis of torque cam mechanism matec web of conferences. The method of release was determined by the normal force acting between the cam and the tappet. Mohammad israr, modeling and simulation for dynamic analysis of cam and follower of valve train system for. Analysis and simulation of cam follower mechanism using. A solid model of the cam is designed in proengineer wildfire 4. The profile of the cam imparts causes a follower to move in a particular way.
Mar 18, 20 cam is a very important topic in the kinematics of machines or theory of machines. The dynamic force analysis determines the cam contact forces and values of. Cam and follower design basics design of cam profiles and. Modelling, design and analysis of cam and follower a. Kinematic and dynamic analysis of mechanisms with cams. The cam follower s force capacity assumes it operates in a perfect environment.
Pdf computer aided kinematic and dynamic analysis of cam and. Cam is a very important topic in the kinematics of machines or theory of machines. Computer aided kinematic and dynamic analysis of cam and. This investigation gives estimates of dynamic forces, hertzian stresses and wear on cam and follower. Luckily, suppliers of cam follower bearings list each cam follower s capacity as a force rather than a stress. Add contact forces to a cam follower mechanism modeled in simmechanics. The pressure angle should be between zero and about 30 for translating. Camfollower report final me 4201 machine design lab. The analytical calculation is done in excel sheet for both kinematic and dynamic analysis of cam follower system for any rotational speed and angle of rise. Modelling, design and analysis of cam and follower international. Dynamic analysis of cam manufacturing longdom publishing sl. A similar arrangement transfers the motion via another roller cam follower to a.
It is very comprehensive, and is currently used by professional engineers. Matlab is used to get optimum values of displacement and velocity. A cam follower retained against the cam with a compression retaining spring will under certain conditions, jump or bounce out. The originality of this method consists of eliminating the friction modulus. Comparison of cam and servomotor solutions to a motion. This analysis is an important step for fixing an optimum size of a cam and. When the motion between the two elements is partly turning and partly sliding, then the pair is known as a higher pair. On the other hand, the force along the axis of the follower exerted by the cam is the driving force of the follower. The last step of dynamic analysis of cam mechanism was to find out some forces which operate in spring and also in pin labeled as a point a when is the cam mechanisms in motion. The offset causes a reduction of the side thrust present in the roller follower. Explain what a cam is, how it is used, and the typical types of cams identify force closed and form closed followers and explain the benefits and limitations of each describe the primary types of cam motion programs introduction to cam design source. Skf cam followers studtype track rollers are designed to run on all types of tracks and to be used in cam drives, conveyor systems, etc.
The peak force on the follower in the direction of motion that is, the useful force is the peak torque divided by the length of the bellcrank arm. Simply we can say that the force generated in the cam follower is the inertia force. An optimum design of cam mechanisms with roller follower. Introduction cam is a mechanical member for transmitting a desired motion to a follower by direct contact. It is the surface area of a cam where follower touches. Computer aided kinematic and dynamic analysis of cam and follower. Use of the vap function in the design of camfollower mechanisms. Additionally, the follower must maintain contact with the cam surface to function properly.
The follower shown in figure 4 c is a flatfaced follower. Research article cam follower mechanism simulation. In both cases the input to the system is the designed cam displacement st and the output is the motion xt of the mass. A flatfaced follower consists of a follower that is formed with a large, flat surface available to contact the cam. Cam follower with a hexagon socket model cfa speci. The driver is called cam and driven is called follower. Introduction of cams and types of cam and followers. The originality of this method consists in eliminating the friction modulus. We proceed on the basis of a force analysis for the. The cam is usually located on shafts and rotates at the uniform speed, whereas the follower motion will be based on the. Kinematic and dynamic variations in cam and follower. In the second part of the work, the cam follower system is analysed for the jump. A cam is a component on which a particular profile has been machined. The model is created by the basic needs of an engine with the available background such as forces acting over the cam by means of valve while running at.
International journal on recent technologies in mechanical. Although we checked the errors, but if you mark some error, let us known in the comment box. A cam follower system is a very simple mechanism that is used for control and conversion of one type of motion. If the design of machines is of real interest, you should take a course on the design of mechanisms. Then, a new threemass, twodegreeoffreedom dynamic model was created. Modeling contact forces in a cam follower video matlab. With the rotation of the cam, the follower the shaft with the roller at bottom in the above picture gets oscillated or translated according to the profile of the cam. It is normally connected with a prime mover, which rotates it. Computer aided kinematic and dynamic analysis of cam.
Point of contact6 this concentrated force can lead to premature wear andor excessive vibration if the cam is not properly sized. A similar arrangement transfers the motion via another roller cam follower to a second rocker arm. This analysis is an important step for fixing an optimum size of a cam and follower. The follower system revolves with respect to the center line of the vertical shaft. Why compare the cam follower with contact force and the cam with contactstress. Its capacity is, however, strongly influenced by lubrication and contamination. I cannot seem to find any cam design references online that discuss the calculations of the cam shaft torque.
Procedia engineering 177 2017 3 a 10 considering the cam geometry, the arm of the force rr, upon which the mass of the follower acts with force, changes depending on its angle of rotation. The cam transfers rotational motion into linear motion by rotating the cam by a shaft connected to an electric motor. The pressure angle is a function of cam rotation angle. After the model was validated, a controlled impact and overtravel mechanism was designed, manufactured, and assembled to a simplified industrial cam follower system, the cam dynamic test machine cdtm. To design the cam and follower we must estimate the contact force. The force ratio for the pressure angle may be expressed by using the kinematics of the mechanism. Background and theory the cam follower experiment is a representation of a mechanical system in 4 which a cam is used to increase the mechanical efficiency of the system. Patel me scholar, department of mechanical engineering, north maharashtra university, jalgaon abstract the objective of this paper is to modelling design and analysis of a cam and follower. Mar 18, 20 a cam is a mechanical device used to transmit motion to a follower by direct contact. The camshaft lobe changes rotary motion camshaft to linear motion valves.
Cam follower bearings have a stud, which means it is cantilevered. In this interactive package the user has options to select i follower motions, ii cam functions, iii motion segments, and iv cam angle increments. Cam mechanism is a case of a higher pair with line contact. Numerical analysis of cam follower mechanism and effect of. Nondissipative systems with two degrees of freedom are discussed, and destabilizing effects due to various types of dissipative. The simulation of cam follower mechanism with 345 polynomial cam profile shows higher follower response at high cam speeds mainly due to the low inertial forces. The force transmission characteristics deteriorate.
Dynamic analysis is also carried out to find out variations in inertia force, spring forces, resultant force and torque of the follower for the full range of motion of cam. Dynamic analysis of cam manufacturing semantic scholar. Characterisation of a directacting and a roller finger. The diagrams show abrupt changes of velocity, which result in large forces at the.
Desai et al 7 developed the program for kinematic and dynamic analysis of the cam and follower and. As the shaft is rotated the cam rotates with it causing the follower to move up and down. Simulation model of cam follower mechanism with 345 polynomial cam profile. Background and theory the cam follower experiment is a. This must be divided by the cosine of the cam pressure angle to get the contact force, which can then be checked against load. Bearings that are specific to cam applications are called trackfollowers and cam follower bearings. Comparison of cam and servomotor solutions to a motion problem. Strength requirements due to the forces and moments acting on the cam.