Obciążalność i trwałość przekładni ślimakowych

Abstract

Verification calculations are indispensable in the design process of any type of structure. Their aim is predominantly to determine whether the exploitation and load capacity limits have not been crossed in the designed structure. They are also applied in worm gears design. The results of verification calculations are the basis for determining the exploitation characteristics of a future gear. If in the design process more than one version of a worm gear has been designed, verification calculations enable carrying out elimination by resigning from the versions that do not meet the predetermined requirements. Basing on the analysis of verification calculations it is possible to decide about the choice of the finał version, the best one out of the versions developed in the design stage. In case of difficulty with taking any of the above mentioned decisions ( elimination or final choice) it is possible to return to -the stage of design calculations and draft of construction of the designed worm gear, being already equipped with the knowledge about where the "barriers" lie within the limits of the gear strain and where the safety "reserve" is excessive in its elements. Concurrent performance of two stages of design and verification calculations during gear design is widely practised and recommended, even for a single item, not mentioning a series or a type series of worm gears. Verification calculations also have other advantages. Having performed a number of experimental researches on real and model gears and having gained experiences in industry it is possible to differentiate empirical relationships, the basis for verification calculations, enabling evaluating explicitly the safety and strain of work of a given worm gear, which constitutes a good corrector of previously made calculations and drafts and of final construction solutions of worm gears based on them. The described method of joining together two stages: preliminary design works on worm gear and verification calculations is particularly effective and advantageous in toothed gears construction. It can be concluded from the above considerations that verification calculations are the finał stage of all mechanical structures design, as they confirm or deny the fact of meeting the predetermined strength and exploitation requirements by the installations. In case of worm gears design verification calculations are to determine if the following values have not been exceeded: mesh resistance to pitting, tooth root resistance to destruction, early abrasive wear of the working surface of teeth, temperature of the gear work, deflection of wormshaft. V erification calculations also include determining the finał efficiency of worm teeth mesh and of the whole gear as well as the degree of its self-locking. The paper provides numerous examples of such calculations.