Підвищення ресурсу гідроциліндрів підйомно-транспортних машин

Abstract

UA: У статті розглянуто актуальне науково-прикладне питання збільшення ресурсу гідроприводу підйомно-транспортних та вантажно-розвантажувальних машин за рахунок автоматичного самоцентрування штоків й усунення однобічного зносу штокових ущільнень гідроциліндрів. Запропоновано принципово нову конструкцію штокового вузла гідроциліндра.

EN: Most lifting and transporting and loading and unloading machines have a hydraulic drive. One of the most common actuators that perform reciprocating and rotary movements are hydraulic cylinders, characterised by one-sided wear of the rod seals. Known rod assemblies are elastic sleeves mounted in the hydraulic cylinder housing, which covers the rod with a guaranteed gap.

During the unit operation, a gap seal forms in the gap between the rod and the sleeve, which prevents the leakage of the working fluid from the high-pressure cavity and centres the rod in the sleeve. However, to ensure the reliable centring of the rod, the intensive flow of the working fluid through the gaps is required, which leads to significant leaks of the working fluid and a decline in the unit efficiency. The optimal gap does not ensure centring, leading to reduced unit durability due to uneven wear of the sleeve and rod. Therefore, the development of new designs of rod seals that ensure self-centring is an urgent task.

The development trends of modern hydraulic drives of construction, track, and loading and unloading machines aim at increasing the pressure of the working fluid up to 32 MPa. It imposes specific requirements on the designs of seals of hydraulic cylinders – the core executive bodies. The analysis of the factors that reduce the durability of reciprocating pair seals shows that it is possible to divide them into several types: wear, aging, operational, and design factors.

The article aims to develop and describe a fundamentally new design of a self-centring rod seal, which can increase the durability of hydraulic cylinders of lifting-transporting and loading-unloading machines without using additional devices.

The analysis of trends in the development of constructions of rod units of hydro cylinders showed that fundamentally new types have emerged among the existing designs, which simultaneously perform two functions – rod guides and sealing. The most notable among them are combined active and passive rod seals.

Passive combined seals of rod assemblies of hydro cylinders differ from traditional ones in that they allow rod movements in the radial direction and allow slight distortions of the rod, compensating for assembly and installation inaccuracies of the assembly.

Active combined seals have the same advantages as passive combined seals but additionally compensate for the wear of the guide sleeve, which increases the durability of the entire rod assembly of the hydraulic cylinder.