Forces and Efficiency of Cams
72
Citation
0
Reference
20
Related Paper
Citation Trend
Abstract:
The paper presents an original method to determine the efficiency of a mechanism with cam and follower. The originality of this method consists in eliminating the friction modulus. In this research it analyses four types of cam mechanisms: 1.The mechanism with rotary cam and plate translated follower; 2.The mechanism with rotary cam and translated follower with roll; 3.The mechanism with rotary cam and rocking-follower with roll; 4.The mechanism with rotary cam and plate rocking-follower. For every kind of cam and follower mechanism one uses a different method to determine the most efficient design. We take into account the cam’s mechanism (distribution mechanism), which is the second mechanism in internal-combustion engines. The optimizing of this mechanism (the distribution mechanism), can improve the functionality of the engine and may increase the comfort of the vehicle too.The paper presents an original method to determine the general dynamics of mechanisms with rotation cams and followers, particularized to the plate translated follower. First, one presents the dynamics kinematics. Then one solves the Lagrange equation and with an original dynamic model with one degree of freedom, with variable internal amortization, it makes the dynamic analysis of two models.
Dynamics
Amortization
Cite
Citations (46)
The paper presents an original method to increase the efficiency of a mechanism with cam and follower. The distribution mechanisms work with small efficiency for about 150 years; this fact affects the total yield of the internal heat engines. Much of the mechanical energy of an engine is lost through the mechanism of distribution. Multi-years the yield of the distribution mechanisms was only 4-8%. In the past 20 years it has managed a lift up to the value of 14-18%; car pollution has decreased and people have better breathing again. Meanwhile the number of vehicles has tripled and the pollution increased again. Now, it’s the time when we must try again to rise the yield of the distribution mechanisms. This paper treats only two modules: the mechanism with rotary cam and plate translated follower and the mechanism with rotary cam and translated follower with roll.
Lift (data mining)
Cite
Citations (12)
The existing cams used in internal combustion engines are made in a variety of forms which have a line contact with follower.As line contact between current cam and follower mechanism results in high frictional losses which results in low mechanical efficiency.Hence in this work an attempt is made to change the flat face of follower by using optimization technique, so that the required length of contact is reduced near about to point contact can be achieved to minimize frictional losses and the efficiency of the cam and roller follower will be improve.
Cite
Citations (0)
The paper presents an original method to determine the efficiency of a mechanism with cam and follower. One analyzes four types of cam mechanisms: 1.The mechanism with rotary cam and plate translated follower; 2.The mechanism with rotary cam and translated follower with roll; 3.The mechanism with rotary cam and rocking-follower with roll; 4.The mechanism with rotary cam and plate rocking-follower. One takes into account the cam’s mechanism (distribution mechanism), which is the second mechanism from the internal-combustion engines. The optimizing of this mechanism (the distribution mechanism), can improve the functionality of the engine and may increase the comfort of the vehicle as well.
Cite
Citations (0)
The paper presents shortly an original method in determining the dynamic of the mechanisms with rotation cam and translated follower with roll. First, one presents the dynamics kinematics. Then one makes the dynamic analyze of few models, for some movement laws, imposed at the follower, by the designed cam profile.
Dynamics
Cite
Citations (1)
A cam swing roller-follower mechanism is designed for the beat-up motion of a horizontal narrow loom. The system consists of a radial plate-cam driven by a camshaft keyed to the plate cam. A slay bar which act as the beater is attached to the radial swing roller-follower and assembled on the plate cam. A continuous contact between the roller follower and the plate-cam is maintained by a spring attached to the follower and fixed to a reference frame to prevent mechanism bounce. The conceptual design for the mechanism is based on the fundamental generalized synthesis procedure. The topology of the kinematics is developed by using the graph theory method of kinematic synthesis. The forces required to drive the plate-cam and follower system were modeled and the components such as the plate-cam, camshaft, the follower and the drive mechanism were synthesized for smooth operation of the mechanism. Analysis of the force requirement show that maximum impact required to beat the weft into the yarn during weaving is achieved at the maximum plate-cam displacement. The acceleration of the cam plate is controlled in the model at the start and end of motion as boundary conditions to specify some degree of stability for the system.
Camshaft
Beat (acoustics)
LOOM
Sprocket
Cite
Citations (1)
The paper presents an original method to determine the efficiency of a mechanism with cam and follower. The originality of this method consists of eliminating the friction modulus. In this paper, one analyzes four types of cam mechanisms: 1. The mechanism with rotary cam and plate translated follower; 2. The mechanism with rotary cam and translated follower with roll; 3. The mechanism with rotary cam and rocking-follower with roll; 4. The mechanism with rotary cam and plate rocking-follower. For every kind of cams and followers mechanism, one uses a different method in determining the best efficiency design. One takes into account the cam’s mechanism (distribution mechanism), which is the second mechanism from the internal-combustion engines. The optimizing of this mechanism (the distribution mechanism), can improve the functionality of the engine and may increase the comfort of the vehicle too.
Cite
Citations (84)
Dynamic stability of a flexible cam-follower system is considered. The shaft-cam-follower assembly is modelled by a single degree-of-freedom system. In the analysis, transverse and rotational flexibility of the camshaft along with flexibility and damping of the follower are taken into consideration. The governing equation of motion for the follower is given by a linear, second-order, ordinary differential equation with time dependent coefficients. In general, this class of equation is known as a second-order Hill's equation. The time responses of the cam-follower system for an eccentric circular cam for different rotational speeds are determined. In addition, stability analysis based on Hill's infinite determinant is performed, and the effects of operational speed and damping on the stability are determined. For the special case of the cam-follower system that has been considered, it has been found that the system is stable for low values of the angular speed of the cam. As the speed is increased gradually, a few unstable regions occur. In general, damping shows a significant effect on stabilizing the cam-follower system.
Camshaft
Cite
Citations (12)
This paper presents an original method to determine the dynamic parameters at the camshaft (the distribution mechanisms). The authors introduce a new pressure angle, alpha, and a new method to determine the two pressure angles, alpha and delta, at the rotary cam and tappet with translational motion with roll, with a great precision. We determine initially the mass moment of inertia (mechanical) of the mechanism, reduced to the element of rotation, ie at cam (basically using kinetic energy conservation, the system 1). The rotary cam with translated follower with roll (Figure 1), is synthesized dynamic. We considered the law of motion of the tappet classic version already used the cosine law (both ascending and descending). The angular velocity is a function of the cam position (j) but also its rotation speed (2). Where ωm is the nominal angular velocity of cam and express at the distribution mechanisms based on the motor shaft speed (3). We start the simulation with a classical law of motion, namely the cosine law. To climb cosine law system is expressed by relations (4). With the relation (5) is expressed the first derivative of the reduced mechanical moment of inertia. It is necessary to determine the angular acceleration (6). Relations (2) and (6) a general nature and is basically two original equations of motion crucial for mechanical mechanisms. For a rotary cam and translated tappet with roll mechanism (without valve), dynamic movement tappet is expressed by equation (7). Where x is the dynamic movement of the pusher, while s is its normal, kinematics movement. K is the spring constant of the system, and k is the spring constant of the tappet spring. It note, with x0 the tappet spring preload, with mT the mass of the tappet, with ω the angular rotation speed of the cam (or camshaft), where s’ is the first derivative in function of j of the tappet movement, s. Differentiating twice successively, the expression (7) in the angle j, we obtain a reduced tappet speed (equation 8), and reduced tappet acceleration (9). Further the acceleration of the tappet can be determined directly real (dynamic) using the relation (10). For a good work one proposes to make a new geometro-kinematics synthesis of the cam profile, using some new relationships (16).
Angular acceleration
Moment of inertia
Camshaft
Cite
Citations (48)