Queensland University of Technology

EGB 214

Executive Summary The VF30 gearbox has a worm drive as an input shaft, which sits on an output gearwheel producing perpendicular torque. It is also characterized by its self-locking ability, which prevents the gearbox to operate in reverse. This makes this gearbox appropriate for practical applications such as lifts, elevators and construction machinery. Additionally, due to its ability to operate with few gears it is able to achieve high gear ratios (with significant speed reduction and torque increase). The disadvantage of this gearbox is that is bears high heat dissipation and power losses due to friction. Long term, this friction will cause the material to wear over time. The housing, input shaft (the worm drive), output shaft and bearing are all large components of the VF30 gearbox and play a major role in the functional and structural composition of the gearbox. This is discussed in depth in the VF30 Worm Gearbox Overview. Smaller components such as the seals, gasket, circlips, spacer and lubricant have less to do with the structural composition of the gearbox, and focus more on the types of fittings between major parts. The different relationships between the major and minor components give specific purpose to the gearbox design. This is also discussed in depth in the VF30 Worm Gearbox Overview and also the Part Relationships section of the report. There are different materials used in the components of the VF30 gearbox that are specifically chosen to achieve certain objectives. Firstly, the housing was built out of aluminium because it can be easily melted, casted, formed and machined making it easy to design and produce through metal casting. It is also very lightweight, and has high corrosion resistance. On the other hand, the input shaft of the worm drive is made of medium carbon steel. Medium carbon steel ductile and strong and is a long-wearing property. This is very suitable material for the worm drive shaft as the VF30 gearbox produces a high torque output. The output shaft is also made of medium carbon steel, however the worm wheel is made of phosphors bronze with steel gear teeth. Bronze is a low-cost metal with self-lubrication properties. This reduces the friction caused by the input and the output shaft. Bronze is also resistant to corrosion. The materials used for the gearbox are discussed in depth in the Material Identification Section of the report (section 5). The manufacturing process for the housing of the gearbox followed the process of metal casting. Metal casting is a process that consists of pouring liquid or molten metal into a mould made of metal, ceramic or sand, to produce components and parts. When the liquid metal is solidified it is removed from the mould and is used for its intended purpose. Methods such as Forging, die casting and machined were also used to manufacture many parts of the gearbox. This is discussed further in the Manufacturing Process Section of the report.