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Manufacturing Methods
Published in Peter Lynwander, Gear Drive Systems, 2019
Figure 7.3 illustrates a shaper cutter machine and Figure 7.4 shaper cutters. Shaping is a generating process where the tool is in the form of a shape conjugate to the tooth being cut. When cutting involute gear teeth the shaper cutter is in the form of an involute gear which is hardened and has cutting clearance on the tooth sides. The gear blank and the cutter are rotated in the proper ratio while the cutter reciprocates axially through the gear blank. If a spur gear is being generated, the cutter will reciprocate through the workpiece in a straight path. To generate a helical gear the cutter must reciprocate in a helical motion which is imparted by a helical guide. This additional tooling required to cut helical gears is a disadvantage of shaper cutting compared to hobbing.
Motion converters
Published in D.A. Bradley, N.C. Burd, D. Dawson, A.J. Loader, Mechatronics, 2018
D.A. Bradley, N.C. Burd, D. Dawson, A.J. Loader
In most industrial applications the prime mover or drive motor will run at a higher speed than the driven machine. Speed increasing or step-up gears are comparatively rare and are confined to specialized machines such as turbo air compressors. Where a speed above the normal 2900 rev min −1 available from standard 50 Hz two-pole induction motors is required, consideration will be given to using high frequency motors. Industrial parallel shaft gears will therefore normally be used as speed reducers, the tooth forms being almost invariably involute and in single helical configuration. Typical reduction ratios per stage are not usually greater than 3:1. Two-stage speed reducers are common, but more than two is exceptional except in the case of very high power ratings, for example the triple reduction double helical gears used on marine steam turbines which range up to 50 000 kW. The practical limit for industrial applications is around 15:1 in double reduction form. Beyond this, the configuration becomes less economical in space utilization than other forms of speed reducer, notably epicyclie gears. The efficiency of involute gear transmissions is very high and can approach 98% per stage.
History of Asymmetric Gears and Modern State of Art
Published in Alexander L. Kapelevich, Asymmetric Gearing, 2018
People have used gears for many centuries. The first, so-called lantern gears, simple rectangular or cylindrical tooth profiles (Figure 1.2) were replaced with more sophisticated cycloid profiles. In the seventeenth century, the Dutch mathematician Christiaan Huygens studied the circle involute, which is the path traced out by a point on a straight line that rolls around a circle, in order to apply it to his first pendulum clock. In the mid-eighteenth century, the Swiss scientist Leonard Euler introduced the involute of a circle for the gear tooth flank profiles. An important feature of the involute gear profiles is producing the theoretically constant rotational velocities’ ratio. Both the cycloid and involute gears, as they are known today, usually have symmetric tooth profiles.
Assessment of contact forces and stresses, torque ripple and efficiency of a cycloidal gear drive and its involute kinematical equivalent
Published in Mechanics Based Design of Structures and Machines, 2022
Hamza Tariq, Zhaksylyk Galym, Andas Amrin, Christos Spitas
The following boundary conditions were used for the dynamical simulations (Figure 5): First, the HSS was given a constant rotational velocity, while the LSS was given resistive torque to oppose free rotation of the HSS. Additionally, the contact behavior between the bearings and the pins, and the bearings and the cycloidal/involute gear is represented by revolute joints with zero friction. The interference between cycloidal/involute gear and the ring gear is given solid-solid contact with constant friction coefficient. The following formula was used to calculate the torque ripple magnitude: where – maximum torque; – minimum torque; – average torque. The low frequency and high-frequency torque ripple components are calculated using Eq. (26).
Compact, backdrivable, and efficient design of linear electro-hydrostatic actuator module
Published in Advanced Robotics, 2022
Mitsuo Komagata, Ko Yamamoto, Yoshihiko Nakamura
We determine the parameters of the cylinder based on the method described in Section 3.4. Parameters are shown in Table 1. We set the maximum joint torque to be 200 Nm and the maximum joint velocity to be 1 rad/s. The limitation of backdrive starting torque is 10 Nm. As for the parameters used for the efficiency estimation, the value of is the internal leakage resistance of the involute gear pump previously developed as a prototype. Values of , , κ, are the parameters of the involute gear pump previously measured in [13]. These parameters are needed to be measured in advance. Parameters e, , and are obtained from the catalog values of OmniSeal1 400A series with the jacket material of A42, which depend on differential pressure and the diameter of a packing. The friction coefficient is the measured value.
Stresses in flex gear of a novel harmonic drive with and without pay load
Published in Australian Journal of Mechanical Engineering, 2022
Vineet Sahoo, Bhabani Sankar Mahanto, Rathindranath Maiti
The conventional HD uses truncated involute teeth to avoid tip interference and loses conjugacy in gearing action as the pitch curve takes the shape of an oval due to the oval-shaped wave generator. To maintain conjugacy in gearing action new (split cam) wave generator has been proposed by Maiti (2004) and Maiti and Roy (1996). The main advantage of the split cam wave generator is that the deformed pitch circle of the FG cup becomes circular around the tooth contact regions separated by two elliptical arcs. This helps to maintain the gearing law around the tooth contact region. Consequently, conjugate gearing action should be achieved with involute gear teeth. Maiti et al. (2012) have also proved that it has higher contact ratio and there may have higher stresses where circular arc has changed to oval-shaped cam. Moreover, the synthesis of suitable tooth profiles (Kondo and Takada 1990; Kayabasi 2007) to work with the conventional oval-shaped cam is one of them. Furthermore, to examine the workability of HD with split-cam SWG, experiments were conducted (Mahanto and Maiti 2011; Biswas, 2005). In the rigorous experiments, the stress-strain analysis is done by placing strain gauges at various places on the FG cup wall surfaces (Mahanto, Sahoo, and Maiti 2018), but the results are limited to strain analysis due to split-cam SWG insertion only.