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Shaft Design
Published in Wei Tong, Mechanical Design and Manufacturing of Electric Motors, 2022
Numerous types of keys are available, including flat keys, square keys, round keys, gib-head keys, feather keys, and Woodruff keys. Among these, flat keys are widely used in the motor industry. To accept a key, longitudinal grooves are made into a shaft and its mating element (e.g., sheave, hub), known as key ways or keyseats. According to the milling pattern, a shaft keyseat can be classified as either sled runner keyseat or profile keyseat. The sled runner keyseats are milled with a disk milling cutter that has the same width of the keyseat. The profile keyseat is produced by a circular endmill that has a diameter equal to the keyseat width (Figure 3.33). Though the type of profile keyseat is widely used in industries, the type of sled runner keyseat is desirable for its lower stress concentration factor. Figure 3.34 presents a PM rotor with a profile keyseat.
Shafts and Associated Parts
Published in Ansel C. Ugural, Youngjin Chung, Errol A. Ugural, Mechanical Engineering Design, 2020
Ansel C. Ugural, Youngjin Chung, Errol A. Ugural
A key enables the transmission of torque from the shaft to the hub. Numerous kinds of keys are used to meet various design requirements. They are standardized as to size and shape in several styles. Figure 9.10 illustrates a variety of keys. The grooves in the shaft and hub into which the key fits form the keyways or key seats. The square, flat type of keys is most common in machine construction.
Effect of Processing Factors on the Composite Formation by FSP
Published in B. Ratna Sunil, Surface Engineering by Friction-Assisted Processes, 2019
Table 9.2 briefly summarizes the maximum thickness of the surface composite layer developed on different material systems by adopting different strategies of secondary phase introduction during FSP. Among all the methods, groove filling method was the first one appeared in the literature in developing surface MMC by FSP. This method is very simple and requires less machining. A groove is machined on the surface of the workpiece by using a milling cutter. Based on the studies done by Gandra et al. [64], the position of the FSP tool pin during the composite formation is found to be crucial. In their work, more powder distribution was observed when the position of the groove was placed under the pin compared with placing the groove away from the pin interaction area (advancing or retrieving). Heydarian et al. [77] proposed another variation in which parallel grooves with gradient groove depths are produced. Compared with providing a single groove on the surface, providing parallel gradient grooves has given uniform distribution of the dispersing powder. Groove filling and closing method requires additional non-consumable pin-less tool. Furthermore, the process is done in two steps; first to close the groove, and in the second to produce the composite. Groove filling and closing method helps to introduce more amount of secondary phase into the workpiece compared with simple groove filling method as the former one prevents the escape of filled powder from the groove during FSP.
Effect of Surface Grooves on the Characteristics of Noncontact Transportation Using Near-Field Acoustic Levitation
Published in Tribology Transactions, 2018
Wenjun Li, Youquan Zhu, Kai Feng, Kai Zhang
The groove parameters, including the groove depth, number, width, and length, are discussed. The results indicate that each of the four parameters should have an optimal value to obtain the best levitation and transportation capabilities. The groove-holding region and the area of the gap are simultaneously influenced by the variation in groove number. Coupling these two reasons determines the optimal groove number. The optimal groove width is determined similar to the optimal groove number. The optimal groove depth with a positive pressure that is not extremely high and negative pressure that is not extremely low obtain the best levitation and transportation capability, respectively. For the variation in groove length, the pressure is seriously rippled by extremely short grooves and flattened by extremely long grooves. Optimal groove length can prevent the two problems simultaneously to obtain the best levitation and transportation capabilities.
Assessment of Screen-Covered Grooved Sodium Heat Pipes for Microreactor Applications
Published in Nuclear Technology, 2022
Donna Post Guillen, Clayton G. Turner
Homogeneous wicks. including wrapped screens, sintered metal, and axial grooves, are commonly used in practice. Screen wicks can take the form of a wrapped screen consisting of several layers of a metal mesh in direct contact with the heat pipe wall or as an open annulus wick that leaves a gap for liquid flow between the wrapped screen and the heat pipe wall. Figure 3a shows the arrangement of an annular wick. Grooved heat pipes are an ideal choice for operation in space (microgravity). They are also a good choice in gravity environments when operating in a favorable orientation where the liquid return is assisted by a gravity component along all sections of the pipe. Axially grooved heat pipes have a circle of grooves along the interior heat pipe wall that efficiently pulls condensate back to the evaporator from the condenser. The grooves can be square, rectangular, triangular, trapezoidal, inverse trapezoidal, or nearly circular shaped.20 Heat pipes with axially grooved inner walls are less sensitive to flow disruptions caused by noncondensable gas impurities and are generally easier to restart following such events. The liquid-vapor interface in a groove manifests as curvature across the groove width rather than along two normal axes of the pores, as is the case for a wick with a homogeneous capillary structure.11 Grooved heat pipes must be operated in a gravity-aided or horizontal orientation, i.e., where the evaporator is at the same elevation as or below the condenser. The grooves provide high permeability and high thermal conductivity. Unfortunately, the groove dimensions tend to be much larger than the pores of a screen or sintered metal wick, which results in a smaller capillary pumping pressure. However, these constant conductance heat pipes can transport heat up to several meters, providing design flexibility. Grooved heat pipes allow a greater range of heat transport than sintered powder metal or screen wick heat pipes. They have been demonstrated to have long lifetimes with high reliability. Axially grooved heat pipes have been successfully used in many applications, such as satellites, spacecraft, space stations, electronics, and permafrost preservation.21 Water and ammonia working fluids have been commonly used for ambient temperature applications of grooved heat pipes.22