234 13 th International Conference on Tribology – Serbiatrib’13 Serbian Tribology Society SERBIATRIB ‘13 13 th International Conference on Tribology Faculty of Engineering in Kragujevac Kragujevac, Serbia, 15 – 17 May 2013 TRIBOLOGICAL ASPECTS OF THE PROCESS OF WINDING THE STEEL ROPE AROUND THE WINCH DRUM Miloš Matejić 1 , Mirko Blagojević 1 , Vesna Marjanović 1 , Rodoljub Vujanac 1 , Boban Simić 2 1 Faculty of Engineering, University of Kragujevac, Serbia, mmatejic@kg.ac.rs, mirkob@kg.ac.rs, vmarjanovic@kg.ac.rs, vujanac@kg.ac.rs 2 D.O.O RAPP Zastava, Serbia, bsi@rappzastava.com Abstract: Proper winding of the steel rope around the winch drum is great importance, mostly for: prolonging the service life of the rope, reduction of deformations of the body and the sides of the drum if the winding of the rope is multilayered, increasing of the safety factors, easier unwinding of the rope while lowering the load, even running of the drive unit, etc. The focus of this paper is on the analysis of the friction which occurs in the process of winding and unwinding the rope around the winch drum. Friction force is in its highest intensity when the rope passes from one layer to another, if the winding of the rope is multilayered. As the result of the research, certain mechanisms of winding of the rope from the aspects of the friction force were obtained, and the affect of the forces on the sides of the drum were analyzed Keywords: winch, drum, rope, friction, friction force. 1. INTRODUCTION Modern technological achievements have enabled a great progress in the ship equipment industry. Ship winches, as one of the most important parts of the equipment, are highly developed. Their dimensions, compared to the force they use, have been reduced and the degree of efficiency has increased with the use of various kinds of compact mechanical gear and drive. The capacities for winding of the ropes have been increased for any kind of use on the vessels, from the oceanographic researches on the bottom of the ocean, to catching of the special kinds of fish. A lot of research into vessel winches have been done: increasing of the degree of efficiency, reduction of dimensions, reduction of the mass of winches, improvement of the drive unit regarding the compactness and the power they use, improvement of the drum for rope-winding as the basic element of a winch, of the rope-winding system, development and analysis of the various types of ropes for various uses, etc. Great attention is paid to examination and development of the ropes used for winches. Steel ropes are mostly used for vessel winches, while the synthetic ones are rarely used. Different types of cables are used for winches for oceanographic researches rather than ropes because of the transmission of information from the research devices from the bottom of the ocean to the vessel. When it comes to the development of the new types of ropes, great attention is paid both to the outer tensile and twisting forces affecting the rope, and the inner friction forces that occur between the wires of the rope, [1], [2], [3]. When examining the existing types of ropes, it is very important to examine the inner friction in the ropes, as well as the failure mechanism of the ropes, [4], [5]. In the case where the steel rope cannot be installed on a winch because of its large mass, synthetic ropes are used. Synthetic ropes are still not widely used because they are still in the development and improvement stages, [6]. Synthetic ropes can be made with the molten core for the improvement of its mechanical characteristics. Reduction of the dimensions and the increase in the degree of efficiency of a winch is mostly achieved by installing the compact mechanical gear, gearboxes. Single-stage gearboxes with two, three or more drives are often used for increasing the compactness of the vessel winch constructions, [7]. In addition, the use of planetary gearboxes is