In summary, main bearings are primarily responsible for supporting the rotational motion of the crankshaft and withstanding radial loads, while thrust bearings are designed to counteract axial forces and maintain the axial position of the crankshaft. Both types of bearings play critical roles in ensuring the smooth and reliable operation of engines and machinery.

In summary, the key difference between angular contact and radial contact bearings lies in their ability to support combined radial and axial loads (angular contact bearings) versus primarily supporting radial loads (radial contact bearings). Each type of bearing is tailored to meet specific operational requirements and environmental conditions in diverse industrial applications.