This master´s thesis solves the problem of stationary viscous flow of incompressible fluids in thin layers of fluid film lubrication in fixed pad thrust bearings. The parametric computational model of oil domain was created for investigation the distribution of pressure, velocity and thermal fields together with the determination of the basic parameters as axial force, heating up and friction loss. Subsequently this model was applied for investigation influence of uneven bearing clearance. The problem task was solved by final volume method in Ansys CFX 12.0 software.

The subject of this diploma thesis is the design solution of the axial headstock, its gear box and main drive. This headstock is used for heavy duty gantry type machines from the production of TOS Kurim company. The thesis contains technical solution of the headstock, an analysis of the construction of the headstock drive, overview of the possible propulsion units, choice of the best drive variant, control calculations, technical proposal of drive design and economical evaluation of the whole reconstruction.

Condition monitoring of hydraulic systems has become more available and inexpensive to implement. However, much of the research on this topic has been done on stationary hydraulic systems without the jump to mobile machines. This lack of research on condition monitoring of hydraulic systems on mobile equipment is addressed in this work. The objective of this work is to develop a novel process of implementing an affordable condition monitoring system for axial piston pumps on a mobile machine, a mini excavator in this work. The intent was to find a minimum number of sensors required to accurately predict a faulty pump. First, an expert understanding of the different components on an axial piston pump and how those components interact with one another was discussed. The valve plate was selected as a case study for condition monitoring because valve plates are a critical component that are known for a high percentage of failures in axial piston pumps. Several valve plates with various degrees of natural wear and artificially generated damage were obtained, and an optical profilometer was used to quantify the level of wear and damage. A stationary test-rig was developed to determine if the faulty pumps could be detected under a controlled environment, to test several different machine learning algorithms, and to perform a sensor reduction to find the minimum number of required sensors necessary to detect the faulty pumps. The results from this investigation showed that only the pump outlet pressure, drain pressure, speed, and displacement are sufficient to detect the faulty pump conditions, and the K-Nearest Neighbor (KNN) machine learning algorithms proved to be the least computationally expensive and most accurate algorithms that were investigated. Fault detectability accuracies of 100% were achievable. Next, instrumentation of a mini excavator was shown to begin the next phase of the research, which is to implement a similar process that was done on the stationary test-rig but on a mobile machine. Three duty cycle were developed for the excavator: controlled, digging, and different operator. The controlled duty cycle eliminated the need of an operator and the variability inherent in mobile machines. The digging cycle was a realistic cycle where an operator dug into a lose pile of soil. The different operator cycle is the same as the digging cycle but with another operator. The sensors found to be the most useful were the same as those determined on the stationary test-rig, and the best algorithm was the Fine KNN for both the controlled and digging cycles. The controlled cycle could see fault detectability accuracies of 100%, while the digging cycle only saw accuracies of 93.6%. Finally, a cross-compatibility between a model trained under one cycle and using data from another cycle as an input into the model. This study showed that a model trained under the controlled duty cycle does not give reliable and accurate fault detectability for data run in a digging cycle, below 60% accuracies. This work concluded by recommending a diagnostic function for mobile machines to perform a preprogrammed operation to reliably and accurately detect pump faults.

Thesis Title: The Quantification of Biomechanical Consequences of Monotonous Sedentary Work to the Axial System Thesis Goals: The goal of the Diploma Thesis is to assess the impact of sedentary work position on the axial system and to find out what changes in biomechanical properties occur specifically in the spine after the specific monotonous eight hours lasting load. Method: Five probands were exposed to diagnostic vibrations of the TVS method (transfer vibration through the spine) before performing eight hours monotonous sedentary work and after it. The examined feature was the ability of the axial system to dampen vibrations spread throughout the spine. Dampening reactions of individual segments were compared to each other before and after the performance of work. Results: The TVS method applied at work has proven its adequacy in the provision of information on resonance frequencies and on the overall attenuation of the spine with sufficient accuracy so that the impact to the axial system after completing the work performance was clearly identifiable. When comparing the frequency dependence and overall attenuation of individual probands we have found that the overall attenuation of the spine increased in all examined individuals. Key words: work, axial system, spine, vibrations and TVS.

Introduction The joint dysfunction of the spine in the sense of functional blockade is connected with corresponding painful condition, reflex contraction of the surrounding muscles and restriction of mobility in the spinal segment. Joint block has its mechanical context, which need not be accompanied by a structural disturbance but it's affecting the biomechanical properties of the spine. Several theories exist how the joints become restricted. Scientific evidence highly supports the meniscoid entrapment theory. Purposes The aim of the study was to identify the meniscoids of the cervical spine using in- vivo MRI imaging and to determine their potential role in the development of functional joint blocks of the axial system (AS). Another objective was to find out how the articular blocks affect the rheological properties of the spine by the Transfer Vibration through the Spine (TVS) method. Patient sample The MRI study was conducted on a research file of 12 subjects - two anatomical preparations and ten in vivo. Two subjects were examined in TVS experiment. Methodology Two anatomical preparations were investigated on MRI to find the appropriate sequence for imaging of meniscoids, three subjects for identification of meniscoids in vivo. Seven subjects underwent initial investigation, manipulation of...

The cylinder block/valve plate interface is a critical design element of axial piston machines. In the past, extensive work has been done at Maha Fluid Power Research center to model this interface were a novel fluid structure thermal interaction model was developed which accounts for thermal and elasto-hydrodynamic effects and has been proven to give an accurate prediction of the fluid film thickness. This paper presents an in-depth investigation of the impact of the elastic deformation due to pressure and thermal loadings of the end case/housing on the performance of the cylinder block/valve plate interface. This research seeks to understand in a systematic manner the sensitivity of the cylinder block/valve plate interface to the structural design and material properties. A comparison between simulations results is done by utilizing different end case designs and material compositions, both in the valveplate and end case solids.

Markets show a clear trend towards an ever more extensive electronic networking in mobile and stationary applications. This requires a certain degree of electronic integration of hydraulic components such as axial piston pumps. Beside some wellknow approaches, the transmission of axial piston units still is relatively unexplored regarding electronification. Nonetheless there is a quite high potential to be optimized by electronic. In view of this fact, the present paper deals with the tribological contacts of pumps based on a demand driven hydrostatic relief. The contact areas at cylinder - distributor plate, cradle bearing and slipper - swash plate will be investigated in detail and it will be shown how the pump behavior can be improved considerably through a higher level of relief and a central remaining force ratio. The potential of optimization is to improve the efficiency, especially in partial loaded operation, power range, also for multi quadrant operation, precision and stability. A stable lubricating film for slow-speed running and for very high speeds at different pressures is ensured as well.

The present study investigates the f ormation of tribolayers on bronze CuSn12Ni2. Two different test rigs are used, of which one is a sliding bearing test rig in order to perform lubricated thrust bearing tests. Bronze CuSn12Ni2 is used for the sliding elements and the counter body is made of C45 steel. In addition to that, an axial piston pump test rig was used to determine t he transfera bility of the results to th e axial pist on pump. The test conditions are set up in a way t hat the tribological load s in the contacts are similar to each other. Changes in the subsurfa ce morphology and the chemical composition of the tribolayer were analysed using electron pro be micro a nalysis (EPMA), trans mission electron microscopy (TEM), energy dispersive X -ray spectro scopy (EDS) and X-ra y photoelectron spectroscopy (XPS). Focused ion beam (FIB) milling was used to prepare site -specific TE M foils fro m the wear track. The formation of a nano scale tribolayer was associat ed with red uced wear, which leads to low leak age in the a xial piston pump. This tribolayer is enriched with oxygen, sulfur and zinc, which is an effect of tribochemical reactions of environment molecules and surface molecules.

Axial piston machines of the swashplate type are commonly used in various hydraulic systems and with recent developments in displacement control, it is essential to maximize their efficiency further reducing operation costs as well as improving performance and reliability. This paper reports findings of a research study conducted for the piston-cylinder interface utilizing a novel fluid structure thermal interaction model considering solid body deformation due to thermal and pressure effects in order to accurately predict the transient fluid film within the gap. A large reduction in energy dissipation is possible due to reduced clearances allowable due to the surface shaping of the piston resulting in a reduction in leakage. From this study, it is shown that surface shaping of the piston in combination with a reduced clearance is not only beneficial by improving the efficiency of a machine, but also increases the reliability and the performance of the machine as the load support is enhanced.

Introduction: Axial spondyloarthritis (ax-SpA) is an inflammatory rheumatic disease. It is a unique model of bone remodeling disorders because, although one of the main diagnostic parameters is the rate of bone formation, inflammation present in patients' bodies increases the risk of pathological bone resorption, which can lead to osteoporosis. The processes of pathological resorption in ax-SpA have not been fully investigated, both in the disease as such and in the individual forms of the disease, i.e. non-radiographic (nr-axSpA), radiographic axial spondyloarthritis (r-axSpA) and ankylosing spondylitis (AS). This work deals with the influence of inflammatory serum of patients on the process of osteoclast differentiation from peripheral precursors of patients and healthy donors. Material and methods: Monocytes separated from the peripheral blood of either axSpA patients or healthy donors were stimulated for 14 days in vitro with serum from patients and in parallel with serum of age and sex of the corresponding healthy donors. Osteoclasts were evaluated as multinucleated, TRAP positive cells. Their numbers were statistically processed. Results: The inflammatory serum environment of patients with axSpA stimulated the osteoclastogenesis of axSpA monocytes significantly more (P <0,05) than the...