Academic literature on the topic 'Hydraulic thread clearance compensation'

Aimed at the characteristic that the leakage of constant clearance seal hydraulic cylinder increases with the pressure escalating, the paper proposed a kind of pressure compensation variable clearance seal hydraulic cylinder based on the metal elastic-plastic theory and the study of clearance seal. The paper analyzed the deformation mechanism and deduced the calculation formula of the deformation. It also had a simulation study of the deformation of the piston lip. By experiment, it gained the variation law of the leakage changing with the pressure changing. Test results showed that, the deformation of the piston can effectively decrease the leakage of the clearance.

Contemporary gear pumps, although their design has been under development for over four centuries, keep being modernized and improved. The work presents an analysis of design solutions, taking into account their operational features. The analysis included units with internal mesh. Emphasis was put on the problem of ensuring high values of volumetric efficiency by minimizing leakage in the widest possible range of loads while maintaining the highest possible hydraulic and mechanical efficiency of the displacement unit. Increasing the volumetric efficiency of positive displacement pumps is an important factor in the pursuit of increase in working pressures in hydrostatic systems. An important factor in production of pumps is cost of their production, which often leads to possibility of introducing additional modifications in the pump structure. Often changes made to the materials used in construction of pumps, allow reduction in their mass or sensitivity to the action of the transported liquid. The paper indicates the developed and proprietary solutions in this area and presents the results of experimental research.

In an eccentric rotating system driven by two hydraulic motors without synchronous gears, vibration coupling may help render motion stable. In order to investigate how vibration coupling influences the motion, the coupling characteristics of the vibration system were studied regarding the differences between two motors such as leakage network, coulomb damping network, and pressure loss network, and the sensitivity of the influence factors was also studied. The influence of tiny differences between the two motors, tiny differences in the motion pair structure, in the oil temperature and in the resistance coefficient on the coupling motion were discovered, and the criterion for synchronous motion were obtained consequently. The results show that the influence of the resistance coefficient difference on system motion stability is the greatest, accounting for 46.7%, and the influence of the difference in motion pair structure (e.g. motor piston clearance) is the second, accounting for 32.8%. For motors with displacement 80 ml/r, the condition of self-synchronization is that the difference in piston clearance between the two motors is equal to or smaller than 6 μm. Experiments have proved the correctness of the theory and showed that the synchronization can be achieved by leakage compensation, damping compensation, and back-pressure compensation of the external system by means of control when the motors rotate slowly enough for system response. The study shows that the coupling synchronous model can reduce the force of the gear for the eccentricity rotary system with synchronous gear, and that the synchronous stability can be improved for the eccentricity rotary system without synchronous gear.

Ménière disease (MD) is a chronic illness of the inner ear that affects a substantial number of patients every year worldwide. Because of a dearth of well-controlled studies, the medical and surgical management of MD remains quite empirical. The main reason is that it is very difficult to investigate patients affected with Certain MD due to the post-mortem criterion necessary for this diagnostic grade. Although Endolymphatic Hydrops (EH) is the worldwide accepted mechanism of MD, the causes that induce it are still not clear. In fact MD has been correlated mostly to a wide and different disturbances ranging from trauma to sleep disorders. It is nowadays sufficiently demonstrated that Chronic Cerebro Spinal Venous Insufficiency (CCSVI) is very frequent in MD. Even if CCSVI may potentially induce EH through a pure hydraulic mechanism CCSVI, per se does not explain how the various disorders correlated with MD may interact with CCSVI and provoke EH. The aim of this review is an attempt to approach MD into the context of the more recent findings about the global brain waste clearance system, to which inner ear is anatomically and functionally connected, in order to build a reasonable model of MD pathogenesis. The major part of the diseases correlated to MD may act on the inner ear disturbing the Glymphatic (GS) and/or Brain Lymphatic System (BLS) activity. The venous system interplays with GS and BLS. In this model CCSVI is considered more than a direct cause of MD rather the anatomical predisposition to develop the disease. In this model EH, and then MD, is the consequence of a failure of the compensation of the congenital venous abnormalities, anatomical compensation as collateral pathways and/or functional compensation as GS and BLS. In this model the major part of the disturbances correlated to MD and the various treatment proposed find their appropriate placement.

This master’s thesis deals with the obtuse-angled cone crushers especially about design of the individual parts of the adjustment mechanism. Most space is devoted to functional calculation and subsequent technical construction of the new design of obtuse-angled crusher where the output setting is adjusted using the motion thread and hydraulic locking system for compensating the thread clearance. The parameters are chosen with regard to the already established older types of cone crushers produced by PSP Engineering, a.s. An inseparable part is the calculation verifying the functionality of the motion thread and gearing. Another essential part of this work are stress analysis of the slot adjusting mechanism design using finite element method and considering two states - adjusting of the slot and crushing itself.