Download or read book Modeling Modal Properties and Mesh Stiffness Variation Instabilities of Planetary Gears written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-15 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: Planetary gear noise and vibration are primary concerns in their applications in helicopters, automobiles, aircraft engines, heavy machinery and marine vehicles. Dynamic analysis is essential to the noise and vibration reduction. This work analytically investigates some critical issues and advances the understanding of planetary gear dynamics. A lumped-parameter model is built for the dynamic analysis of general planetary gears. The unique properties of the natural frequency spectra and vibration modes are rigorously characterized. These special structures apply for general planetary gears with cyclic symmetry and, in practically important case, systems with diametrically opposed planets. The special vibration properties are useful for subsequent research. Taking advantage of the derived modal properties, the natural frequency and vibration mode sensitivities to design parameters are investigated. The key parameters include mesh stiffnesses, support/bearing stiffnesses, component masses, moments of inertia, and operating speed. The eigen-sensitivities are expressed in simple, closed-form formulae associated with modal strain and kinetic energies. As disorders (e.g., mesh stiffness variation. manufacturing and assembling errors) disturb the cyclic symmetry of planetary gears, their effects on the free vibration properties are quantitatively examined. Well-defined veering rules are derived to identify dramatic changes of natural frequencies and vibration modes under parameter variations. The knowledge of free vibration properties, eigen-sensitivities, and veering rules provide important information to effectively tune the natural frequencies and optimize structural design to minimize noise and vibration. Parametric instabilities excited by mesh stiffness variations are analytically studied for multi-mesh gear systems. The discrepancies of previous studies on parametric instability of two-stage gear chains are clarified using perturbation and numerical methods. The ope

Download or read book Modeling Modal Properties and Mesh Stiffness Variation Instabilities of Planetary Gears written by and published by . This book was released on 2001 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: Planetary gear noise and vibration are primary concerns in their applications in helicopters, automobiles, aircraft engines, heavy machinery, and marine vehicles. Dynamic analysis is essential to the noise and vibration reduction. This work analytically investigates some critical issues and advances the understanding of planetary gear dynamics. A lumped-parameter model is built for the dynamic analysis of general planetary gears. The unique properties of the natural frequency spectra and vibration modes are rigorously characterized. These special structures apply for general planetary gears with cyclic symmetry and, in practically important case, systems with diametrically opposed planets. The special vibration properties are useful for subsequent research. Taking advantage of the derived modal properties, the natural frequency and vibration mode sensitivities to design parameters are investigated. The key parameters include mesh stiffnesses, support/bearing stiffnesses, component masses, moments of inertia, and operating speed. The eigensensitivities are expressed in simple, closed-form formulae associated with modal strain and kinetic energies. As disorders (e.g., mesh stiffness variation, manufacturing and assembling errors) disturb the cyclic symmetry of planetary gears. their effects on the free vibration properties are quantitatively examined. Well-defined veering rules are derived to identify dramatic changes of natural frequencies and vibration modes under parameter variations. The knowledge of free vibration properties, eigensensitivities and veering rules provide important information to effectively tune the natural frequencies and optimize structural design to minimize noise and vibration. Parametric instabilities excited by mesh stiffness variations are analytically studied for multi-mesh gear systems. The discrepancies of previous studies on parametric instability of two-stage gear chains are clarified using perturbation and numerical methods.

Download or read book VIBRATION AND NOISE REDUCTION IN PLANETARY GEAR TRAIN BY PHASING written by Ashutosh Mokate and published by Anchor Academic Publishing. This book was released on 2016-07 with total page 117 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gears are essential parts of many precision power transmitting machines such as automobiles. The major functions of a gearbox are to transform speed and torque in a given ratio and to change the axis of rotation. Planetary gears yield several advantages over conventional parallel shaft gear systems: They produce high speed reductions in compact spaces, a greater load sharing, a higher torque to weight ratio, diminished bearing loads, and reduced noise and vibration. They are used in automobiles, helicopters, aircraft engines, heavy machinery, and a variety of other applications. Despite their advantages, the noise induced by the vibration of planetary gear systems remains a key concern. Planetary gears have received considerably less research attention than single mesh gear pairs. There is a particular scarcity of analysis of two planetary gear systems and their dynamic response. Hence, this book focuses on the study of two PGTs with different phasing (angular positions) while every individual set remains unchanged.

Download or read book Advances in Technical Diagnostics II written by Andrzej Puchalski and published by Springer Nature. This book was released on 2023-05-20 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reports on recent theories and methods for diagnostics and condition monitoring of machines, materials and industrial processes, with a special emphasis on the application of artificial intelligence and intelligent control systems. Gathering original contributions to the 7th International Congress on Technical Diagnostics, ICTD2022, held on September 14–16, 2022, in Radom, Poland, this book offers extensive information on the latest trends in machine diagnostics and on IoT, smart sensors and machine learning technology in advanced condition monitoring. It addresses both scientists and professionals and is intended to foster communication and collaborations between the two groups.

Download or read book Mechanical Engineering written by Murat Gokcek and published by BoD – Books on Demand. This book was released on 2012-04-11 with total page 686 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book substantially offers the latest progresses about the important topics of the "Mechanical Engineering" to readers. It includes twenty-eight excellent studies prepared using state-of-art methodologies by professional researchers from different countries. The sections in the book comprise of the following titles: power transmission system, manufacturing processes and system analysis, thermo-fluid systems, simulations and computer applications, and new approaches in mechanical engineering education and organization systems.

Download or read book International Gear Conference 2014 26th 28th August 2014 Lyon written by Philippe Velex and published by Chandos Publishing. This book was released on 2014-09-18 with total page 1225 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents papers from the International Gear Conference 2014, held in Lyon, 26th-28th August 2014. Mechanical transmission components such as gears, rolling element bearings, CVTs, belts and chains are present in every industrial sector and over recent years, increasing competitive pressure and environmental concerns have provided an impetus for cleaner, more efficient and quieter units. Moreover, the emergence of relatively new applications such as wind turbines, hybrid transmissions and jet engines has led to even more severe constraints. The main objective of this conference is to provide a forum for the most recent advances, addressing the challenges in modern mechanical transmissions. The conference proceedings address all aspects of gear and power transmission technology and range of applications (aerospace, automotive, wind turbine, and others) including topical issues such as power losses and efficiency, gear vibrations and noise, lubrication, contact failures, tribo-dynamics and nano transmissions. A truly international contribution with more than 120 papers from all over the world A judicious balance between fundamental research and industrial concerns Participation of the most respected international experts in the field of gearing A wide range of applications in terms of size, power, speed, and industrial sector

Download or read book Vibration of Planetary Gears Having an Elastic Continuum Ring Gear written by Xionghua Wu and published by . This book was released on 2010 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: The primary goal of this work is to develop mathematical models for planetary gears having an elastic ring gear to conduct numerical and analytical studies to understand the modal properties, parametric instability, and nonlinear gear dynamic behaviors. First, natural frequencies and vibration modes are determined as closed-form expressions for a ring having a circumferentially varying foundation of very general description through perturbation and Galerkin analyses. The simple eigensolution expressions explicitly show the parameter dependencies, lead to natural frequency splitting rules for degenerate unperturbed eigenvalues at both first and second orders of perturbation, and identify which nodal diameter Fourier components contaminate a given n nodal diameter base mode of the free ring. As an application and as the motivating problem for the study, the natural frequencies and vibration modes of a ring gear used in helicopter planetary gears with unequally spaced planets are investigated. Second, the distinctive modal properties of equally spaced planetary gears with elastic ring gears are analytically studied through perturbation and a candidate mode method based on an elastic-discrete model. Two perturbations are used to obtain closed-form expressions of all the eigenfunctions. In the Discrete Planetary Perturbation (DPP), the unperturbed system is a discrete planetary gear with a rigid ring. In the Elastic Ring Perturbation (ERP), the unperturbed system is an elastic ring supported by the ring-planet mesh springs; the sun, planet and carrier motions are treated as small perturbations. All vibration modes are classified into rotational, translational, planet and purely ring modes. The well defined properties of each type of mode are analytically determined. All modal properties are verified numerically. Also the modal properties of planetary gears having diametrically opposed planets and an elastic ring gear are studied through the candidate mode method. Two types of modes are found: rotational and translational modes. Fourth, the parametric instability of planetary gears having elastic continuum ring gears is analytically investigated based on the elastic-discrete model. By using the structured modal properties of planetary gears and the method of multiple scales, the instability boundaries are obtained as simple expressions in terms of mesh parameters. Instability existence rules for in-phase and sequentially phased planet meshes are also discovered. For in-phase planet meshes, instability existence depends only on the type of gear mesh deformation. For sequentially phased planet meshes, the number of teeth on the sun (or the ring) and the type of gear mesh deformation govern the instability existence. The instability boundaries are validated numerically. Finally, the nonlinear dynamics of planetary gears having an elastic ring gear is studied. The frequency-response functions are presented for primary, subharmonic, and superharmonic resonances. The tooth separation phase between meshes depends on the mode type excited and the position of the planets. The resonances associated with a translational or planet mode are investigated. Parametric instability rule and mesh deflection phase expression are confirmed in the numerical simulation for both in-phase and sequentially phased planets. Response of planetary gears having commensurate natural frequencies is also studied.

Download or read book Mechanism Design for Robotics written by Alessandro Gasparetto and published by Springer. This book was released on 2018-08-30 with total page 453 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the Proceedings of the 4th IFToMM Symposium on Mechanism Design for Robotics, held in Udine, Italy, 11-13 September, 2018. It includes recent advances in the design of mechanisms and their robotic applications. It treats, among others, the following topics: mechanism design, mechanics of robots, parallel manipulators, actuators and their control, linkage and industrial manipulators, innovative mechanisms/robots and their applications. This book can be used by students, researchers and engineers in the relevant areas of mechanisms, machines and robotics.

Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on 2002 with total page 808 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book VIBRATION AND NOISE REDUCTION IN PLANETARY GEAR TRAIN BY PHASING written by Ashutosh Mokate and published by diplom.de. This book was released on 2016-03-10 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt: Gears are essential parts of many precision power transmitting machines such as automobiles. The major functions of a gearbox are to transform speed and torque in a given ratio and to change the axis of rotation. Planetary gears yield several advantages over conventional parallel shaft gear systems: They produce high speed reductions in compact spaces, a greater load sharing, a higher torque to weight ratio, diminished bearing loads, and reduced noise and vibration. They are used in automobiles, helicopters, aircraft engines, heavy machinery, and a variety of other applications. Despite their advantages, the noise induced by the vibration of planetary gear systems remains a key concern. Planetary gears have received considerably less research attention than single mesh gear pairs. There is a particular scarcity of analysis of two planetary gear systems and their dynamic response. Hence, this book focuses on the study of two PGTs with different phasing (angular positions) while every individual set remains unchanged.

Download or read book PRICM 6 written by Young Won Chang and published by . This book was released on 2007 with total page 928 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Analytical Study on Compound Planetary Gear Dynamics written by Yichao Guo and published by . This book was released on 2011 with total page 245 pages. Available in PDF, EPUB and Kindle. Book excerpt: The back-side mesh stiffness variation is inspected in this work to address the needs for gear vibration models that consider the gear tooth contacts on the back side. The results reveal the inherent relationship between the back-side and drive-side mesh stiffnesses. The impact of backlash on the back-side mesh stiffness variation function is also quantified.

Download or read book Dynamics of Planetary Gear Trains written by and published by . This book was released on 1984 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Computerized Generation and Simulation of Meshing of Modified Spur and Helical Gears Manufactured by Shaving written by and published by . This book was released on 2001 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modification of geometry of spur and helical gears with parallel axes and helical gears with crossed axes is proposed. The finishing process of gear generation is shaving. The purposes of modification of the gear geometry are to localize and stabilize the bearing contact, and to reduce noise and vibration. The goals mentioned above are achieved by using profile crowning and plunging the shaver by a prescribed motion during pinion generation. The pinion becomes double crowned. The gear member is generated as a conventional involute gear. A tooth contact analysis (TCA) program for simulation of meshing and contact was developed and the analysis is illustrated with TCA results for spur and helical gears.

Download or read book Advances in Condition Monitoring of Machinery in Non Stationary Operations written by Alfonso Fernandez Del Rincon and published by Springer. This book was released on 2019-02-07 with total page 423 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is aimed at researchers, industry professionals and students interested in the broad ranges of disciplines related to condition monitoring of machinery working in non-stationary conditions. Each chapter, accepted after a rigorous peer-review process, reports on a selected, original piece of work presented and discussed at the International Conference on Condition Monitoring of Machinery in Non-stationary Operations, CMMNO’2018, held on June 20 – 22, 2018, in Santander, Spain. The book describes both theoretical developments and a number of industrial case studies, which cover different topics, such as: noise and vibrations in machinery, conditioning monitoring in non-stationary operations, vibro-acoustic diagnosis of machinery, signal processing, application of pattern recognition and data mining, monitoring and diagnostic systems, faults detection, dynamics of structures and machinery, and mechatronic machinery diagnostics.

Download or read book Modeling of Multi mesh Gear Dynamic Analysis Based on Pseudo interference Stiffness Estimation written by Geunho Lee and published by . This book was released on 1997 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advances in Mechanism Machine Science and Engineering in China written by Xinjun Liu and published by Springer Nature. This book was released on 2023-05-31 with total page 2228 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the conference proceedings of the 23rd IFToMM China International Conference on Mechanism and Machine Science & Engineering (IFToMM CCMMS 2022). CCMMS was initiated in 1982, and it is the most important forum held in China for the exchange of research ideas, presentation of technical and scientific achievements, and discussion of future directions in the field of mechanism and machine science. The topics include parallel/hybrid mechanism synthesis and analysis, theoretical & computational kinematics, compliant mechanisms and micro/nano-mechanisms, reconfigurable and metamorphic mechanisms, space structures, mechanisms and materials, structure adaptation in space environment and ground testing, large-scale membrane deployable structures, construction and application of super-scale space systems, cams, gears and combining mechanisms, fluid power mechatronics drivetrain, mechanical design theory and methods, dynamics and vibration control, mechatronics, biologically inspired mechanisms and robotics, medical & rehabilitation robotics, mobile robotics, soft robotics, heavy non-road mobile machine, robot applications, engineering education on mechanisms, machines, and robotics. This book provides a state-of-the-art overview of current advances in mechanism and machine science in China. The inspiring ideas presented in the papers enlighten academic research and industrial application. The potential readers include academic researchers and industrial professionals in mechanism and machine science.