Marek Krynke

Modelling the Contact between the Rolling Elements and the Raceways of Bulky Slewing Bearings

In slewing bearings, a great number of contact pairs are present on the contact surfaces between the rolling elements and raceways of the bearing. Computations to determine the load of the individual rolling elements, taking into account the flexibility of the bearing ring, are most often carried out using the finite element method. Construction of a FEM full model of the bearing, taking into account the shape of the rolling elements and the determination of the contact problem for every rolling element, leads to a singularity of stiffness matrix, which in turn makes the problem impossible to solve. In FEM models the rolling elements are replaced by one-dimensional finite elements (linear elements) to simplify the computation procedure and to obtain an optimal time for computations. The methods of modelling the rolling elements in the slewing bearing, in which balls have been replaced by truss elements with a material non-linear characteristic located between the raceway centres of the curvatures in their axial section, are presented in the paper.

Computation of the general carrying capacity of slewing bearings

Purpose – The purpose of this paper is to discuss the calculation problem of the real carrying capacity of slewing bearings. The selection of slewing bearing to heavy-duty machine according to catalogue carrying capacity and also according to locally determined real carrying capacity is insufficient and it can be the cause of the damage of machine during exploitation. Design/methodology/approach – The concepts of the local, total and general capacities is defined. The general capacity is a logical product of the local capacities. It is particularly useful in an analysis of slewing bearings incorporated into machines with complex structures. The FEM is applied in computations. The formation method of the mathematical model of a bearing is presented. Findings – The computations of the local capacities and general capacity of a bearing for the limiting load of the bearing traces and the limiting tension of the bolts fastening the bearing were carried out. Considerations were illustrated by an example of the ...

PLASTIC PRODUCTION MACHINERY – THE EVALUATION OF EFFECTIVENESS

Abstract In this paper TPM and PAMCO coefficients were shortly characterised. On the basis of TPM coefficients its effectiveness was estimated. Thanks to using time and PAMCO coefficients, the utilization of working time machines was researched. Moreover, there a correlation between TPM coefficient and the quality level was examined. A histogram was drawn up in order to illustrate the distribution. The obtained results allowed to evaluate the effectiveness of the machine. The period of research embraced fifty-two weeks (1 year) and the object of the analysis is the injection moulding machine.

Numerical analysis of bolts loading in slewing bearing

This article analyzes screw connection of slewing bearings to various structures of support elements. The susceptibility of support elements to the load distribution in particular bearing screws was examined by means of the Finite Element Method. The load values of screws and their distribution around the perimeter of the combined bearing rings were also specified.