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Chain Reaction
Published in Norbert Majerus, George Taninecz, Winning Innovation, 2022
Norbert Majerus, George Taninecz
Mo kicks offhis presentation with an in-depth technical overview of a direct-drive mechanism and its application to a bicycle. He speaks as though he’s talking to a room of engineers and shows detailed cutaways of direct-drive gear mechanisms found in hand tools and other machines, such as ski lifts he rode during the winter. He also shows drawings of how he would connect the pedals to the gear box—a key part of Mo’s concept is the solid-drive shaft that connects the gear box to the rear bike wheel. Mo has spent significant time on the engineering drawings of the proposed mechanism and explains each in great detail to the executive team.
General Components of Machine Tool
Published in Ajay M. Sidpara, Ganesh Malayath, Micro Electro Discharge Machining, 2019
Ajay M. Sidpara, Ganesh Malayath
To improve the response characteristics of tool positioning and retraction system in EDM, local actuators are recommended by various researchers. Masuzawa (1975) studied the possibility of using a voice coil actuator for EDM tool feed control. An impact drive mechanism and a direct drive mechanism are introduced for EDM feed control (Higuchi et al., 1991). Imai et al. (1996) used a high-frequency response piezoelectric actuator in EDM and reported that the machining rate is improved 1.5–2.5 times by high response jumping action of the tool electrode. Various micromotion technologies are invented for precise control of the ultraprecision machine tools including shape memory alloy actuators (Sadeghzadeh et al., 2012), ultrasonic motors (Maas, 2000), stick-slip actuators (Zhang et al., 2006), and complaint mechanisms (Hongzhe et al., 2015). However, most of the researchers employed piezoelectric actuators and maglev actuators for microfeed control in micro EDM. Imai et al. (2004) used a local actuator based on electromagnets with thrust coils for drilling microholes and fabricating micro dies. A microfeed technology based on inchworm mechanism is developed by Li et al. (2002).
Adjustment Mechanisms
Published in Anees Ahmad, Handbook of Optomechanical Engineering, 2017
Janssen et al.17 have described a direct drive mechanism where a lever is used to enhance the resolution of an actuator in a tilt mechanism. A simplified one-dimensional representation of this concept is shown in Figure 9.48. By implementing two actuators in an orthogonal pattern with respect to a fixed pivot, such mechanism can provide a two-axis tip–tilt adjustment.
Effects of Back Iron Components on Efficiency and Generated Power for New Wind Energy Generators
Published in Electric Power Components and Systems, 2018
The wind energy systems can be classified as the geared and direct-drive systems [15]. The direct-drive mechanism have some superiorities such as higher reliability, lower maintenance, reduced noise, and increased efficiency compared to the geared drives. In addition to wind energy applications, the direct-driven PMSG can be an interesting solution for tidal energy systems, since they are characterized by high levels of torque densities, efficiency, and reliability [15,16]. These advantages attract the attention of the turbine manufacturers to design and implement direct-drive machines. It can be also mentioned that the gearbox is one of the main cause of downtime and failure in turbine systems. Concerning the characteristics and practical requirements of the direct-driven tidal stream turbines having low speed and high torque, the axial flux (AF) generators can be an attractive solution, because these machines can improve the torque density and be less difficult in manufacturing than transverse flux (TF) machine. Those structures enable a better torque density, since it is possible to multiply the number of air gap in the system [15,16]. One should also mention on some drawbacks, for example, the strong axial magnet attraction force between the stator and the rotor which is leading to the difficulties in maintaining the uniform air gap. Indeed, it is one of the main reasons why the radial flux (RF) machine has become standard in electrical machine sector and developed more than the AF ones [16]. Another drawback of the low-speed direct-driven AFPM wind-generator is that it requires larger diameter affecting the material cost [17].