The influence of design parameters on the impact forces is investigated for the 4-bar crank-rocker mechanism with multi-clearances. A system of differential equations is obtained by assuming all links to be rigid and using the impact pair model of Dubowsky for clearance joints and solved numerically for various combinations of design parameters. The ratio of the maximum impact force of the clearance mechanism to the maximum joint force of the corresponding nominal mechanism is defined as the clearance effect and taken as the major quantity to be investigated. The minimum transmission angle, mass distribution, input angular velocity and magnitude of clearances are taken as design parameters.
It is observed that the clearance effect increases as the minimum transmission angle increases and decreases as the input angular velocity or the mass of links increases. It is also shown that for moderate range of clearances there exist some combinations of clearances which reduce the clearance effect considerably. Considering that the clearance effect should be minimized under the constraint of manufacturing cost, that is a desirable feature for assigning tolerances to joints. But its systematic prediction hard at present state and remained as a future research topic.
