Kinematic and Geometric Analysis of a Pure-Rolling Epicyclic Train

2006 ◽  
Vol 129 (8) ◽  
pp. 852-857 ◽  
Author(s):  
Chao Chen ◽  
Xiang Zhang ◽  
Jorge Angeles
Keyword(s):  
Coulomb Friction ◽  
Mechanical Design ◽  
Geometric Analysis ◽  
Rolling Contact ◽  
The Sun ◽  
Innovative Design ◽  
Speed Reduction ◽  
Pure Rolling ◽  
Speed Reducer ◽  
Gear Trains

This paper reports an innovative design of epicyclic (planetary) cam trains based on pure-rolling contact, intended to overcome the drawbacks of gear trains, such as Coulomb friction and backlash. The kinematic relations of the mechanism with a given speed-reduction ratio are analyzed; accordingly, the profiles of the sun cam and ring cam, key elements of the mechanism, are obtained. Furthermore, the condition for undercutting avoidance of the ring cam is derived. For mechanical design, different layouts of the epicyclic cam trains are discussed for the structure and transmission optimization. Finally, an epicyclic cam-roller speed reducer is designed and prototyped.

The Design of a Novel Mechanical Transmission for Speed Reduction

1999 ◽  
Vol 121 (4) ◽  
pp. 538-543 ◽  
Author(s):  
M. A. Gonza´lez-Palacios ◽  
J. Angeles
Keyword(s):  
Mechanical Transmission ◽  
Speed Reduction ◽  
Spatial Mechanisms ◽  
Pure Rolling ◽  
Speed Reducer

The design of a novel transmission for speed reduction is reported in this paper. The transmission is based on the layout of pure-rolling indexing cam mechanisms, for it is intended to eliminate backlash and friction, which are the main drawbacks of gear transmissions. The design relies on a unified methodology for indexing cam mechanisms, whereby the same procedure is used to design planar, spherical, and spatial mechanisms. Two versions of the speed reducer, that we term Speed-o-Cam, are described here, namely, planar, to couple shafts of parallel axes, and spherical, to couple shafts of intersecting axes. By means of a cascade of two planar versions of Speed-o-Cam, moreover, coaxial shafts can be coupled. Moreover, contrary to other alternatives to gear transmissions, such as harmonic drives or epicyclic transmissions, Speed-o-Cam caters to shafts with either parallel or intersecting axes; in the latter case, moreover, the angle at which the axes intersect can vary from 0° to 180° continuously. The design with shaft axes at 0° leads to an internal cam, i.e., one with its axis external to the axes of the follower and the roller in contact; for shaft axes at 180°, the design leads to an external cam, i.e., one with its axis lying between those of the follower and the roller in contact.

The Design of a Novel Mechanical Transmission for Speed Reduction

1998 ◽  
Author(s):  
Max A. González-Palacios ◽  
Jorge Angeles
Keyword(s):  
Mechanical Transmission ◽  
Speed Reduction ◽  
Spatial Mechanisms ◽  
Pure Rolling ◽  
Speed Reducer

Abstract The design of a novel transmission for speed reduction is reported in this paper. The transmission is based on the layout of pure-rolling indexing cam mechanisms, and hence, eliminates backlash and friction, which are the main drawbacks of gear transmissions. The design relies on a unified methodology for indexing cam mechanisms, whereby the same procedure is used to design planar, spherical, and spatial mechanisms. Two versions of the speed reducer, that we term Speed-o-Cam, are described here, namely, planar, to couple shafts of parallel axes, and spherical, to couple shafts of intersecting axes. By means of a cascade of two planar versions of Speed-o-Cam, moreover, coaxial shafts can be coupled. The proposed design thus eliminates the drawbacks of gear transmissions without bringing about those of harmonic drives or epicyclic transmissions, which nevertheless work only for coaxial shafts.

A Lightweight Split-Torque Transmission for a 330 KW Helicopter

1982 ◽  
Vol 196 (1) ◽  
pp. 11-22 ◽  
Author(s):  
G White
Keyword(s):  
Gear Train ◽  
Main Rotor ◽  
Speed Reduction ◽  
Torque Transmission ◽  
Current Production ◽  
Gear Trains ◽  
Fixed Axis ◽  
Three Stages ◽  
A Current ◽  
Split Torque

A simple split-torque gear train is used as the main rotor transmission of a single-engine helicopter. Overall speed reduction ratio achieved is 103:1 between the engine at a nominal 36 000 rev/min and the main rotor at 350 rev/min. This ratio is generated from three stages of fixed-axis gear trains containing only eight gears. Alternative configurations are outlined and discussed. Comparison with a current production design shows the split torque arrangement offers reductions in weight, height, and drive train losses. A low total of gears and bearings offers the potential for improved reliability.

Analysis of Elliptical Rolling Contact Joints in Compression

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
Jacob R. Montierth ◽  
Robert H. Todd ◽  
Larry L. Howell
Keyword(s):  
Rolling Contact ◽  
Contact Interface ◽  
Force Transmission ◽  
Hertz Contact ◽  
Surface Geometry ◽  
Low Friction ◽  
High Quality ◽  
Gear Teeth ◽  
Revolute Joints ◽  
Pure Rolling

This paper presents elliptical rolling contact joints in compression as an alternative to circular rolling contact and conventional revolute joints where high quality force transmission—low friction and backlash—with variable output are desired. Parameters specific to the joint and its position are defined in terms of relative link angles and elliptical surface geometry. These relationships allow elliptical rolling contact joints to be incorporated in vector loop summations used in kinematic analysis. Notably, elliptical rolling contact is developed as the more general case of which circular rolling contact is a subset. Elliptical rolling contact joints are shown to offer several benefits over circular rolling contact, including reduced Hertz contact stresses, variable output velocity, maximum use of contact interface by distributing small rotations across surfaces of small curvature, reduced forces on constraining members, and no-slip pure rolling provided by either connecting links or flexures, without the need for gear teeth or friction.

On the Design of Planar and Spherical Pure-Rolling Indexing Cam Mechanisms

1992 ◽  
Author(s):  
Max Antonio González-Palacios ◽  
Jorge Angeles
Keyword(s):  
Coulomb Friction ◽  
Power Losses ◽  
Unified Framework ◽  
Pressure Angle ◽  
Pure Rolling

Abstract A new design of indexing cam mechanisms for parallel and intersecting shafts is presented here in a unified framework, so that both pure rolling and positive motion are achieved. Power losses due to Coulomb friction are eliminated, while producing motions free of jerk discontinuities. The pressure angle is anlyzed and applied to define the positive motion.

Parabolic Sun Tracking Solar Distillation System

2009 ◽  
Author(s):  
Omar O. Badran ◽  
Ismail M. A. Arafat ◽  
Salah A. Abdallah
Keyword(s):  
Image Processing ◽  
Renewable Energy ◽  
Mechanical Design ◽  
Renewable Energy Sources ◽  
The Sun ◽  
Self Monitoring ◽  
Water Distillation ◽  
Water Pumping ◽  
Solar Distillation ◽  
Distillation System

The main aim of the present study is to draw attention to the possibilities and to the measures of appropriate utilization of renewable energy to achieve what is called “water self-sufficient” for arid regions in Jordan. Also to put efforts of increasing the use of renewable energy sources to lower cost of potable water pumping and gives more economical benefits. Another aim of the current research is to utilize the new control algorithm and the developed computer capabilities in the field of sun tracking in order to improve the efficiency of solar distillers. The new tracking method is utilized for water distillation taking advantage of high possible concentration of parabolic trough collector to reach high levels of daily yield per square meter. The present research utilizes the techniques of image processing to catch the core of the sun as the target, also used artificial intelligence techniques to predict the sun position in abnormal conditions (i.e. cloudy, dusty, rainy). The results of sun tracking using image processing found to be accurate and reliable according to the self monitoring of the focus point validated by the solar radiation results. Water distillation yield shows high percentage output of distillate of about 65% of water supplied to distiller. Mechanical design was tested for high ability to withstand the extra loading. It was found that the output yield reached to noticeable levels, because of the use of the parabolic collector that promoted the solar still efficiency.

Research on Mechanical Engineering with Innovative Design of Gantry Planer

2013 ◽  
Vol 345 ◽  
pp. 27-30
Author(s):  
Chang Fa Wang ◽  
Feng Lan Wang
Keyword(s):  
Energy Cost ◽  
Mechanical Engineering ◽  
Production Efficiency ◽  
Mechanical Design ◽  
Work Efficiency ◽  
Innovative Design ◽  
Improve Production ◽  
Improve Production Efficiency

The design for traditional gantry planer aims at its empty stroke and low work efficiency of the two fatal flaws in this paper. We adopted the structure innovation by mechanical design and designed the gantry planer bidirectional shaping turret. And the device is simple in structure and easy in manufacture. These make improved gantry planer remove empty stroke and change one-way shaping into two-way shaping. Thus the improved gantry planer can depress energy cost consumedly and improve production efficiency. This will broaden its market greatly in the machining industry.

A Study on the Design and Performance of Epicycloid Bevels of Pure-Rolling Contact

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Rulong Tan ◽  
Bingkui Chen ◽  
Dongyun Xiang ◽  
Dong Liang
Keyword(s):  
Negative Influence ◽  
Transmission Efficiency ◽  
Rolling Contact ◽  
Tooth Surface ◽  
Element Analysis ◽  
Surface Theory ◽  
Pure Rolling ◽  
Surface Models ◽  
And Performance ◽  
Mechanics Characteristics

To avoid the negative influence of sliding contact, this paper tries to investigate the spiral bevels of pure-rolling contact that can be manufactured by existing manufacture technology. In this process, spatial conjugate curve meshing theory and conjugate surface theory are both introduced to investigate the geometric principles and face hobbing process of the pure-rolling contact epicycloid bevel (PCEB for short in this paper). The tooth surface models of PCEBs by face hobbing process are obtained. Next, a sample is represented to show an application of this model. Then, finite element analysis (FEA) is applied to investigate the contact mechanics characteristics of these gears. Finally, the performance experiment of a prototype is completed to evaluate the deviations between theoretical expectations and practical results. From the FEA and experimental results, it is concluded that the PCEBs can mesh correctly and achieve a higher transmission efficiency.

Design of a Robotic Cannula for Robotic Lumber Discectomy

2019 ◽  
Author(s):  
Yang Ding ◽  
Benjamin V. Johnson ◽  
David J. Cappelleri
Keyword(s):  
Controller Design ◽  
Mechanical Design ◽  
Lumbar Discectomy ◽  
Surgical Instruments ◽  
Herniated Disc ◽  
Axial Position ◽  
Robotic Approach ◽  
Instrument Translation ◽  
Gear Trains ◽  
Fully Functioning

Abstract In this paper, the design of the robotic cannula for minimally invasive robotic lumbar discectomy is presented. Lumbar discectomy is the surgery to remove the herniated disc material that is pressing on a nerve root or spinal cord. Recently, a robotic approach to performing this procedure has been proposed that utilizes multiple teleoperated articulated instruments inserted into the surgical workspace using a single cannula. In this paper, we propose a new robotic cannula system to work in conjunction with this new procedure. It allows for the independent teleoperated control of the axial position and rotation of up to three surgical instruments at the same time. The mechanical design, controller design, and prototype of new system are presented in this paper demonstrating a fully functioning device for this application. A novel worm gear and rack system allow for the instrument translation while and embedded gear trains produce the rotational movement. Steady-state errors of less than 50 μm for translation and less than 2° for rotational motion are obtained.

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