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Gears
Published in Asok Kumar Mallik, Amitabha Ghosh, Günter Dittrich, Kinematic Analysis and Synthesis of Mechanisms, 1994
Asok Kumar Mallik, Amitabha Ghosh, Günter Dittrich
A combination of gears of similar or different types used for transmitting motion from one shaft to another is known as a gear train. Figure 10.11-1 shows a gear train consisting of bevel, spiral and spur gears. When the axes of rotation of all the gears in a train are fixed, with respect to the frame, the train is called an ordinary train. The train shown in Fig. 10.11-1 is an ordinary train. When at least one of the gear axes rotates relative to the frame in addition to the gear’s own rotation about its own axis, the train is called a planetary gear train, or an epicyclic gear train. The term “epicyclic” comes from the fact that points on gears with moving axes of rotation describe epicyclic paths. The ordinary gear trains are further classified into two types: (i) simple gear train and (ii) compound gear train. The most important kinematic analysis of the gear trains involves the determination of the motion of all members when that of the input member is prescribed. Often it is necessary to find out the ratio of angular velocities of the input (the first) gear and the output (the last) gear of a train. The input gear and the output gear of a train are also referred to as the driving and the driven gears, respectively. The speed ratio14R=ωdriver/ωdriven
Gear Ratio of a Multistage Gear Drive
Published in Stephen P. Radzevich, Theory of Gearing, 2018
A gear train can be composed either of gear pairs of the same type (that is, all the gear pairs in a gear train are cylindrical parallel-axes gear pairs), or it can be composed of gear pairs of different types. For example, a gear train can be composed either of (1) bevel and cylindrical gear pairs, (2) a worm gear pair and a cylindrical gear pair, or (3) a hypoid gear pair and a cylindrical gear pair, and so forth. In the first case, the entire gear ratio is evenly distributed among all the stages of the gear train. In the rest of the cases, additional investigation is necessary, as losses of power in gear pairs of different kinds are also different, regardless of certain correlations among the range of losses.
Layshaft gearboxes
Published in M.J. Nunney, Light and Heavy Vehicle Technology, 2007
In this analogy we have therefore arrived at the lever equivalent of a simple gear train in which the pinion would be half the size of the gear and would have only half as many teeth. The relationship between the numbers of teeth on the gears of a simple gear train is known as their ratio to one another. In the example just given, the ratio would be expressed as 2:1; similarly, if the pinion had only one-third as many teeth as the gear then the ratio would be 3:1.
A novel continuously variable-speed offshore wind turbine with magnetorheological transmission for optimal power extraction
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
The power loss of the fixed ratio speed-increasing gearbox transmission mainly includes tooth surface meshing friction loss, bearing friction loss, lubricating oil stirring loss, etc. (Pennestrì et al. 2012). The power loss of tooth surface meshing friction is related to the design parameters of gear meshing point position, addendum circle and index circle pressure angle. The bearing friction loss is related to the rolling friction coefficient, speed, and temperature, etc. The stirring loss of lubricating oil increases with the increase of the spindle speed, and decreases with the increase of the input torque. Therefore, the transmission efficiency of the gear train is defined as a function of the operating state variables of the gear train, which is (Qiao et al. 2008)
Experimental investigation on load mitigation of a 5 MW wind turbine in digital fluid power pitch system test rig based on predictive load mitigation controller
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Valayapathy Lakshmi Narayanan, Arun Tom Mathew
where Γls is the low-speed shaft torque (rotor side), ωr is the speed of the rotor, ωls is the speed of the low-speed shaft, Ir is the inertia of the rotor, ϕr and ϕls are angular deviations at the rotor side and gear-train side, respectively, Γg is the generator torque, Kr is the external damping of the rotor, Kls and Fls are the low-speed shaft damping and stiffness, respectively. The torque at high-speed shaft Γhs drives the generator inertia Ig,Kg is generator damping, and ωg is the generator speed. The gear-train ratio Ngb is defined as .
Design, prototype development and pre-clinical validation of a novel instrument with a compliant steerable tip to facilitate endoscopic ear surgery
Published in Journal of Medical Engineering & Technology, 2021
Arushri Swarup, Kyle W. Eastwood, Peter Francis, Nichtima Chayaopas, Lueder A. Kahrs, Colin G. Leonard, James Drake, Adrian James
The actuation wheel meshes with a smaller gear which is concentric to a worm, which meshes with a worm gear, see Figure 5. The worm gear with a ratio of 1:14 is from a guitar tuning set which is widely available and inexpensive for prototyping. The worm gear drives the rotation of a lead screw within the handle that allows a nut to translate along it. The shaft contains the cable that is attached to the tip. The cable exits the shaft and is rigidly attached to a nut-cable attachment component. Translation of this nut causes tension in the cable and tip articulation. The pitch of the lead screw is 25.4 mm and one full rotation of the worm causes the nut to translate 1.81 mm along the lead screw. The desired cable displacement to close each notch for full articulation is 0.8 mm, thus a total of 3.2 mm of cable displacement is required to fully articulate the tip [17]. The worm requires 1.77 rotations for full articulation. As per the comments from Testing Session 4 for Handle B, multiple rotations of the worm were not comfortable during operation of the instrument. Thus, a spur gear train or actuation gear train was coupled to the worm to reduce the number of turns required. The goal was to require less than one full rotation of the actuation wheel for full articulation and so the target gear ratio of the actuation gear train was at least 2:7. The gear ratio for the actuation gears is 1:4 and full articulation is achieved with less than one rotation.