No description available.

This Master’s thesis deals with the proposal manufacturing technology of a shaft with gears on a CNC machine tool. The first part of the thesis is focused on the concise description selected shaft and its use. In the next part of the thesis are state selected materials, which are suitable used for shafts and gears. After that is create drawing component, suggest technological procedure, tool list and machine list which are suitable used for manufacturing selected shaft. In the final part of the thesis is create a CNC program for manufacturing the shaft on the turning and milling machine. Program is created in software SinuTrain 4.7 for control system Sinumerik 840D. The CNC program is verified by graphics simulation to determine a correct function

No description available.

The gears in a transmission are lubricated to prevent their premature failure as a result of pitting and wear on the tooth surfaces. Furthermore, the lubricant also limits the rise in surface temperature of the gears, which could otherwise lead to failure as a result of scuffing. The purpose of this thesis was to construct a fairly realistic theoretical lubrication model for spur and helical gears, the primary output parameters of this model being film thickness and flash temperatures, which would help in the identification of areas on the gear tooth surface prone to the aforementioned modes of failure. This thesis was carried out at the Gear Technology group in Scania CV AB in collaboration with the department of machine design at KTH. Gear lubrication is tricky as it entails the determination of parameters such as loads, curvatures, and velocities; which are different along the entire surface of the gear tooth. Primarily the loads are hard to obtain as they are dynamic in nature; the load is shared between different pairs of teeth during motion. The calculation of velocities and curvatures in an area of the gear surface called the tip relief can also not be done in a straightforward manner. These issues were simplified to a large extent with the assistance of a program called Helical 3D; owing to its powerful contact analysis algorithm, values of the film thickness and flash temperatures could be determined in almost every region where contact occurred between the gear teeth. The results of the lubrication model showed a reduction in film thickness in the tip relief area of the gear tooth surface; which meant that there were higher chances for the incidence of pitting and wear in this region. This was later confirmed when photographs from experimental tests illustrated a pitting line in the tip relief region of the helical gear. It was also inferred from the model that the occurrence of pitting could be greatly reduced if a quadratic tip relief modification were applied when compared to the existing linear modification used at Scania. Another important conclusion drawn was that thermal effects contributed to a significant decrease in the film thickness. Furthermore, the model showed higher flash temperatures close to the tip of the gear tooth surface, and photographs from experiments conducted showed the prescence of scuffing marks there.

The objective of this thesis is to find and develop methods that enhance and support the creation of evolvable master process plans with possibilities to challenge productivity and meet changing design requirements. The condition for achieving this is primarily that both the fundamental thinking and the results behind a process plan can be described. How should this be done? The focus is laid on process planning of gear transmission parts for heavy vehicles like trucks and coaches. Process planning is the activity where design and manufacturing are brought together with the common target to achieve both a competitive product and production process. There are many factors that influence the process planner when a new product or process shall be introduced for production. Process planning is, in most cases, performed by an experienced, skilled person but without any defined methodology or way of working. Much of the process planning is based on the retrieval of solutions already used. Much research effort has been devoted to developing systems for computer-aided process planning (CAPP). Yet CAPP systems have not been accepted and spread over a wide front within the manufacturing industry, much because of the functional incompleteness combined with the difficulties of adopting knowledge and changing requests. A method for systematic process planning is proposed as a way to perform and describe the procedure of creating a process plan. The method facilitates the interpretation and understanding of the plan, not only immediately for the process planner responsible, but also for designers, engineers, researchers and other interest groups involved in a manufacturing process. In the last chapter is a case study regarding manufacturing of a bevel gear pinion presented to exemplify use of the proposed method for systematic process planning. / KUGG

The general trend in gear industry, today, is an increased focus on gear transmission efficiency. Gear transmission efficiency losses arise from loaded and unloaded gear contacts, seals, lubricant and bearings. One way of minimising the losses is to lower the lubricant viscosity. This will reduce the speed dependent losses. However, the load dependent losses might increase. To avoid this, the ratio between lubricant film thickness and surface roughness must be maintained, which can be fulfilled by producing smoother gear surfaces. As a starting point for this realisation process, the present manufacturing processes, the design tools and the characteristics of the gear flank interface must be further investigated and developed. This must be achieved with an emphasis on economic production. This thesis focuses on our understanding of how different gear manufacturing methods —particularly the contribution of the running-in process—affect the surface characteristics, with the view of increasing gearbox efficiency. The thesis consists of a summary and three appended papers. Paper A and paper B discuss the relationship between design parameters and real gear wheel surfaces manufactured with different manufacturing methods. The research hypothesis was that the contact area ratio is a descriptive parameter for the contact condition. Paper A deals with the influence of manufacturing method on the initial contact conditions and also serves as a validation of the simulation program used. The emphasis in Paper B is the changes that occur during running-in, and to correlate these changes to design requirements. Paper C approaches the influences of manganese phosphate-coating and lubricants with respect to friction and the risk of scuffing at the initial contact. The main conclusions of this thesis are that the contact area ratio presents a descriptive measure of how surface topography influences the contact, seen at both a global (form deviation) and local (roughness) level. The surface topography caused by the manufacturing method has a significant influence on the contact area ratio. This is an important result, since neither national standards nor commercially available gear evaluation programs handle surface topography on the local scale. Shaving was found to have the highest contact area ratio, and should therefore be the best choice if deviations from case hardening could be minimised. It is also confirmed that gear-like surfaces coated with manganese phosphate have a low coefficient of friction, and raise the limiting load for scuffing failure enormously compared to the ground equivalent. / <p>QC 20100518</p> / KUGG / Sustainable gear transmission realization

In recent years, there has been an increase in the development of drone technologies. Furthermore a considerable interest in developing drones that utilizes platforms allowing for adaptive morphology has been growing steadily. In this work, we use a quadcopter to develop a drone with the feature of transforming its shape from a flat triangle to a tetrahedron. To achieve this property, two main features are considered. First, a controller for the propeller thrust force to control the movement of the triangular side facet. Second, a 60-degree angled bevel gear is used to ensure the positioning concurrency of the facets. In this study, we use MATLAB simulations to study the feasibility of the proposed concept. We use the simulations to determine the base requirement for the controller dynamics by simulating the output angle of the facets and to study the effect of the controllers on the angle reached by the facets. In addition, we perform an experimental analysis to validate our results from the simulations. We investigate the design limitations of the controllers and check the feasibility of the proposed drone design by studying the thrust force generated. The simulations and experiments showed that the presence of bevel gears can reduce the controller dynamics requirement to only a proportional controller. Furthermore, the thrust test for this drone design showed an estimated thrust force of approximately 1.7 times the thrust of a single motor. These results are promising and contribute to setting the foundation for more rigorous study of this design of drones, which have a noticeable impact on the ease of packaging and transportation applications.

No description available.

No description available.

No description available.