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Shaft Design
Published in Wei Tong, Mechanical Design and Manufacturing of Electric Motors, 2022
The term coupling refers to a device that is used to connect two shafts together at their ends. The primary function of a motor coupling is to transmit torque or power from a motor shaft to the shaft of the driven machine. However, in the real world, whatever precautions are taken to make alignments as precise as possible, the alignment between two separate shafts is never perfect. Some amount of residual misalignment will inevitably remain. Misalignments are resulted not only from the improper installation, but also from the variations of temperature and other factors. Consequently, it forces rigid components such as shafts to defect, causing vibration of the system and bring uneven loads on bearings and system frame. Therefore, it is vital to design couplings properly to compensate for misalignment to ensure normal operation of motor and driven machine.
Shafts and Associated Parts
Published in Ansel C. Ugural, Mechanical Engineering Design, 2022
In addition to the shaft itself, the design usually must include calculation of the necessary keys and couplings. Keys, pins, snap rings, and clamp collars are used on shafts to secure rotating elements. The use of a shaft shoulder is an excellent means of axially positioning the shaft elements. Figure 9.2 shows a stepped shaft supporting a gear, a crowned pulley, and a sheave. The mounting parts, discussed in Section 9.8, as well as shaft shoulders, are a source of stress raisers, and they must be properly selected and located to minimize the resulting stress concentrations. Press and shrink fits (Section 9.6) are also used for mounting. Shafts are earned in bearings, in a simply supported form, cantilevered or overhang, depending on the machine configuration. Couplings connect a shaft to a shaft of power source or load. Parameters that must be considered in the selection of a coupling to connect two shafts include the angle between the shafts, transmitted power, vibrations, and shock loads. The websites www.pddnet.com, www.powertransmission.com, and www.grainger.com present general information on shaft couplings.
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
In addition to the shaft itself, the design usually must include calculation of the necessary keys and couplings. Keys, pins, snap rings, and clamp collars are used on shafts to secure rotating elements. The use of a shaft shoulder is an excellent means of axially positioning the shaft elements. Figure 9.2 shows a stepped shaft supporting a gear, a crowned pulley, and a sheave. The mounting parts, discussed in Section 9.8, as well as shaft shoulders, are a source of stress raisers, and they must be properly selected and located to minimize the resulting stress concentrations. Press and shrink fits (Section 9.6) are also used for mounting. Shafts are earned in bearings, in a simply supported form, cantilevered or overhang, depending on the machine configuration. Couplings connect a shaft to a shaft of power source or load. Parameters that must be considered in the selection of a coupling to connect two shafts include the angle between the shafts, transmitted power, vibrations, and shock loads. The websites www.pddnet.com, www.powertransmission.com, and www.grainger.com present general information on shaft couplings.
Application of active magnetic bearings for in situ flexible rotor residual balancing using a novel generalized influence coefficient method
Published in Inverse Problems in Science and Engineering, 2019
A flexible rotor-bearing system integrated with AMBs, as shown in Figure 1, has been considered for the study. It consists of rigid discs mounted on flexible shafts that are connected by couplings. The AMBs are used as controlling devices to prevent excessive vibrations at high speeds. Flexible shafts are supported on conventional bearings with cross-coupled stiffness and damping terms. AMBs have linearized cross-coupled displacement and current stiffnesses. In this rotor system, discs are assumed to be balancing planes and residual unbalances are estimated in these planes. A proportional–integral–derivative (PID) controller is used for AMBs.
Modeling of flexible damped coupling and its influence on rotor dynamics
Published in Mechanics Based Design of Structures and Machines, 2022
For engineering applications, the rotors are often segmented into the driven and driveshaft, joined by coupling, which again produces misalignment. Misalignment is categorized into three types, that is, parallel, angular, and a combination of these two. A misaligned shaft creates specific directional preloads, which may cause severe vibrations and result in many problems like looseness, bends in shafts, wear and tear of bearings, inertial imbalance, etc. The magnitude of this preload depends on the amount of misalignment, and a proper choice of coupling may reduce it up to some extent. Coupling is primarily categorized into two types—rigid and flexible couplings. Rigid couplings may be used for the equipment having negligible misalignment and robust enough to handle the reactionary load. The rigid couplings are essential of four types: flanged rigid coupling, ribbed rigid coupling, rigid sleeve coupling, and quill shaft rigid coupling. Detailed analysis of rigid couplings was proposed by Rivin (1986) and Piotrowski (1995). Misalignment effect in the dynamic response of rotors connected by rigid couplings was presented by Lees (2007) and Redmond and Al-Hussain (2002). In other words, flexible couplings are recommended when the degree of misalignment is high and the equipment is used for high-speed application. The flexible coupling can be classified into disk coupling, gear coupling, chain coupling, and universal joint. From the application point of view, a flexible coupling has three essential criteria—it transmits power, accommodates misalignment to some acceptable range and compensates for end movement. Identifying the main factors of misalignment that influence lateral vibration, the selection of proper flexible coupling was completed by Woodcock (1977) and Grigor (1982). Descriptions of several coupling models ranging from conventional gear-type couplings to more recent diaphragm coupling were explained in the book by Bloch and Geitner (1990) and Mancuso Jon (1999).
Latest technologies and novel approaches in coal seam gas centrifugal compressor trains in Australia
Published in Australian Journal of Mechanical Engineering, 2019
Misalignment of the main drive coupling, even within its tolerance limits, puts increased loads on adjacent shaft bearings; it also reduces the service life of the coupling, as flexible elements are subjected to greater strains.