Dynamic analysis of the basic mechanism of a technological machine

The paper presents an example of the use of a crank-rocker mechanism as a part of two machines: low-speed and high-speed. In the first case, the basic mechanism is a part of a two-cylinder reciprocating compressor, in the second case it is a part of a six-link mechanism. It contains a crank-rocker mechanism and it contains a crankrocker mechanism and L.V. Assura’s structural group. It contains a link and a hollow prism hinged to the post.

The dynamic analysis of the crank-rocker mechanism has been performed. The total reactions in its vapors have been determined. At the first stage, the nature of the change in the components of speed and acceleration of the center of the connecting rod is established. Diagrams of angular velocities of the connecting rod and rocker are given. The diagrams have been analyzed. At the second stage, the total reactions in the pairs of the mechanism from the action of inertia forces have been determined. It is shown that the reactions in pairs formed by a crank with a rack and with a connecting rod, respectively, change identically. The total reaction in the rocker-stand pair has an oscillating character of change in time. At the third stage, in addition to the forces of inertia, the influence of the nature gravity of the change in reactions has been taken into account. It has been established that at a given angular velocity of the crank, the inertial forces make an insignificant contribution to the values of the total reactions. At the fourth stage of the dynamic analysis of the mechanism, in determining the reactions, the forces of inertia and gravity, as well as the forces of friction, have been taken into account. The coefficient of friction is assumed to be 0.4 in all pairs of the mechanism. Accounting for friction when determining reactions leads to their local bursts in the vicinity of its three positions. These are the two extreme positions and the minimum position of the transmission angle. The total reactions in the pairs of the basic mechanism are determined mainly by the gravity forces of the links at the chosen angular velocity of the crank. As a result of the performed dynamic analysis of the basic mechanism, the parameters have been obtained. They are needed to study the stress-strain state and assess the strength of the mechanism links.

1. Gorlatov A. S. Mekhanizm dlya peredachi silovykh nagruzok [Mechanism for transferring power loads]. Patent RF 2127842, no. 98108118/28, 1999.

2. Gorlatov A. S., Sereda N. F. Manipulyator dlya peredachi izdeliy [Manipulator for the transfer of products]. Patent RF 2356726, no. 2007136532/02, 2009.

3. Antoville A. M. Teoriya mekhanizmov i mashin [Theory of mechanisms and machines]. Moscow, Vysshaya shkola Publ., 1961, 254 p.

4. Semenov Yu. A., Semenova N. S. Dinamicheskie oshibki v mashine s uprugimi zven'yami [Dynamic errors in a machine with elastic links]. Teoriya mekhanizmov i mashin, 2019, no. 2 (42), pp. 61–68.

5. Zhoga V. V., Vershinina I. P. Dinamicheskiy analiz ploskikh sterzhnevykh mekhanizmov [Dynamic analysis of flat bar mechanisms]. Teoriya mekhanizmov i mashin, 2018, no. 4 (40), pp. 150–161.

6. Evgrafov A. N., Babichev D. T., Lebedev S. Y. Flat lever mechanisms: new strategy for kinematic analysis and computer simulation of motion. Mechanisms and Machine Science, 2019, no. 3, pp. 537–548.

7. Evgrafov A. N., Andrienko P. A. The role of St. Petersburg scientists of the XVIII–XIX centuries in the development of machines and mechanisms science. International Review of Mechanical Engineering, 2016, no. 10 (5), pp. 312–321.

8. Evgrafov A. N., Petrov G. N. Calculation of the geometric and kinematic parameters of a spatial leverage mechanism with excessive coupling. Journal of Machinery Manufacture and Reliability, 2013, no. 42 (3), pp. 179–183.