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Modification of a multi-recess hydrostatic bearing pad geometry
Šimara, Vít ; Robenek, Dětřich (referee) ; Svoboda, Petr (advisor)
In the design of a hydrostatic bearing, basic analytical expressions assuming parallelism of sliding surfaces and simple geometry can be employed. In this study, the properties of a specific pocket shape were investigated even under conditions of tilt, which can arise from assembly errors or asymmetric loading. Based on experimental data, a Computational Fluid Dynamics (CFD) model of hydrostatic lubrication has been developed and validated. A constant flow through all recesses was considered and conditions of no movement of the sliding surface were assumed. The model was subsequently modified to a variant with discharge grooves separating individual recesses and a variant with variable recess position relative to the centre of the pocket. The results demonstrated that the pocket's ability to carry asymmetric loading increases mainly with increasing distance of the recess from the centre, followed by their size. However, this ability comes at the cost of higher performance losses in hydrostatic lubrication. The results of this work can be used for the design of pockets with different methods of pocket support or alignment.
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Design of pneumobil driven by pneumatic motor
Podhorský, Petr ; Robenek, Dětřich (referee) ; Nevrlý, Josef (advisor)
Master thesis deals with design of "student" pneumatic car equipped by pneumatic elements of a chosen firm. The introductory part is devoted to mapping the Hungarian competition. The idea of designing such vehicles comes from this competition. Next step is analysis of vehicles that are present in this competition. The main part describes the development of vehicle from the initial design, through analysis of main components, through to the production and presentation. The work contains a strain-stress analysis of the frame which is made by using the finite element method. The work ends with the conclusion which assesses the results.
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Design of DH bike fork with magnetorheological damper
Salva, Matúš ; Robenek, Dětřich (referee) ; Strecker, Zbyněk (advisor)
When mountain biking over rough terrain, comfort and sufficient wheel pressure are often the limiting factors. That's why there is an effort to innovate suspension and develop dampers that provide better damping characteristics. The usage of semi-active suspension is one way to achieve the desired improvement over the currently used passive systems. In this work, the aim was to develop a magnetorheological damper that is suitable for implementation in commonly available mountain bike forks and whose damping characteristics allow the use of the Skyhook algorithm. A functional model of an MR damper with a stroke of 240 mm and an outer diameter of 29.5 mm, whose dynamic range is 9.5 at a piston velocity of 0.25 ms-1 and a time response of 17 ms, was developed. The magnetic circuit of the manufactured functional pattern is of 11SMn30. The damper served to verify the functionality of the concept and at the same time its damping characteristics were experimentally verified and compared with the predicted values. Due to the combination of numerical and analytical model, a very good agreement between prediction and experiment was achieved. Hence, an MR damper with a magnetic circuit made of Hiperco/Vacoflux 50 material was subsequently designed with a predicted dynamic range of 9.5 and a time response of less than 10 ms. The resulting total weight of the design is 0.68 kg. This design fully satisfies all requirements. When used in combination with semi-active control using the Skyhook algorithm, it is predicted to improve ride comfort by 28 %. The potential to use the proposed MR damper is with the increasingly widespread electric bicycles mainly due to the higher weight in conjunction. At the same time, however, the possibility of using it on a regular bicycle is not excluded. Semi-active suspension is a new and not yet widely used technology in cycling and has the potential to reach a new range of consumers. Considering all the advantages and disadvantages, it can be concluded that the proposed MR shock absorber allows to improve the rideability of mountain bikes both in terms of ride comfort, wheel traction or in the form of reduced energy expenditure during pedalling due to energy absorption by the suspension.
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Knee Ankle Foot Orthosis with Hydraulic Knee
Vávra, Jan ; Robenek, Dětřich (referee) ; Koutný, Daniel (advisor)
This master thesis deals with the engineering design of a knee-ankle orthosis and subsequent implementation of a functional sample. The subject of the first part of the thesis is the design of internal shape of the shell on the basis of the patient's leg using CAD software. The second part deals with the design of the hydraulic knee. The knee joint with hydraulic controlled bending enables easier movement for patients who are not able to bring up stairs and uneven surfaces than existing joints. In the implementation was used SolidWorks 2012 and Geomagic Studio 12.
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Adjustable portal for hydraulic pulsator Inova
Buchta, Tomáš ; Robenek, Dětřich (referee) ; Mazůrek, Ivan (advisor)
The aim of this thesis is the innovation of the testing device which is located in Institute of Machine and Industrial Design laboratory. The innovation relates to the portal construction design, where will be placed the hydraulic pulsator from the company INOVA Praha Ltd. New portal construction will be designed with respect to specified parameters and requirements and also with regard to the performed tests (damper tests, vibroizolated properties magnetorheological valves tests etc.). The thesis contains detailed analysis of the current tester and detailed analysis of similar machines with focusing on the portal structure and ways of positioning the crossmember. Further parts of the thesis is a detailed description of the design solution, including the computational simulations, attached drawing documentation and experimentally verified functional sample (crossmember).
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Determination of efficiency of hydraulic drive with recuperation
Kobza, Michal ; Robenek, Dětřich (referee) ; Nevrlý, Josef (advisor)
In the first part of the thesis is determined efficacy criterion for the individual operating modes of the experimental stand with energy recovery and subsequently are evaluated the records of individual measurements. Energy savings are calculated with using energy recovery. The second part describes the process of digitizing relative fuel consumption map of the engine. Results are confronted with a real application engine in the road roller Ammann AP 240 H. In addition, the master thesis describes the creation of hydrostatic converter block in the program MATLAB/Simulink 2012b. Creating block can be used in the development of simulation models.
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Theory of pneumatic car design
Stodolák, Martin ; Robenek, Dětřich (referee) ; Nevrlý, Josef (advisor)
This thesis covers the theoretical solution of the compressed air powered vehicle. The first section describes the competition of the compressed air powered vehicles, that is annually held in Hungary, where the idea for such a car design was created. There are also additional descriptions of the construction of the machines from the hungarian competition. In the second section there is a calculation of the chosen vehicle construction, where the main emphases is based on the calculation of the drive of the vehicle. The description of the manufacturing, tests and vehicle presentation follows.
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Design of wayside unit for top-of-rail lubrication
Valena, Martin ; Robenek, Dětřich (referee) ; Galas, Radovan (advisor)
This master’s thesis describes design and realization of a wayside unit for top-of-rail lubrication (TOR). TOR lubricant application causes wear reduction and lower noise emission. Firstly, patent analysis was provided and critically evaluated according to which requirements for developed device were specified – accurate dosage of small lubricant volume and high repeatability. On the basis of concept design, an experimental rig was created and used for lubricant application verification and spray lubrication parameter identification. Acquired results are considered in the final design of wayside unit with a technical facility. Two utility models were created within this master’s thesis.
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Design of valve block for hydrostatic recuperative module of vehicle
Ranuša, Matúš ; Robenek, Dětřich (referee) ; Nevrlý, Josef (advisor)
The Master`s Thesis deals with design and construction of a valve block for a hydrostatic recuperative module of a vehicle with a direct application on pneu tyred roller AP 240H produced by the AMMANN company. The thesis aims to analyze recovery functions of the valve block in several operating modes of the roller, followed by a selection of the right hydraulic components from the perspective of predefined parameters and pressure differences. Design specifications are based on measurements and mathematical simulations on the experimental stand. The experimental stand for this application has been developed at 1:4 scale as compared to a real vehicle. The thesis includes also design of the supporting console for the module on the frame of the vehicle. The Master`s Thesis is a part of project EUREKA with cooperation Bosch Rexroth.
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Hydromobil - design of mechanical-hydraulic recovery of car kinetic energy
Stodolák, Michal ; Robenek, Dětřich (referee) ; Nevrlý, Josef (advisor)
This diploma thesis deals with the structural design of a vehicle powered by pressure fluid that is stored in a hydraulic-pneumatic accumulator. The first part described the types of energy recovery, especially hydraulic recovery. Furthermore there are outlined basic parameters of the design of the vehicle driving mechanism. The second part describes the design of hydromobile with emphasis on the chassis, especially the driving and braking system. Additional information on the individual parts of the chassis, that are put through the stress analysis. The final part deals with the actual manufacturing of the hydromobile and is followed by the resume of the thesis.
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