A finite element method for 3D static and dynamic contact/impact analysis of gear drives

Load distribution model along the line of contact for involute external gears

This book re-examines the rationale for public policy, concluding that the prevailing ‘public knowledge' model is evolving towards a networked or distributed model of knowledge production and use in which public and private institutions play complementary roles. It provides a set of tools and models to assess the impact of the new network model of funding and governance, and argues that governments need to adapt their funding and administrative priorities and procedures to support the emergence and healthy growth of research networks. The book goes on to explain that interdependencies and complementarities in the production and distribution of knowledge require a new and more contextual, flexible and complex approach to government funding, monitoring and assessment.

Links and Impacts: The Influence of Public Research on Industrial R&D

The twenty-first century is a knowledge-based and increasingly environmental age. Many countries are introducing new policies and production concepts that are consistent with these trends. Recently, interest in recycle, reuse and remanufacturing technologies has been increasing, with the eco-friendly and energy-efficient production. One of these eco-friendly production methods, remanufacturing, is defined as a series of processes to re-commercialize end-of-life products and parts as new products. Various remanufacturing markets already exist throughout the world. However, the size and types of remanufacturing markets differ from country to country according to technological level and national policy. In this paper, a literature review of trends and issues related to the remanufacturing from the last five years was performed. Then, the global remanufacturing landscape, including the types of remanufactured goods, the scale of the markets and national policies in the major remanufacturing countries was summarized. Also, approaches in the design of disassembly and several remanufacturing technologies, including cleaning and repairing, are provided from the last three years.

Remanufacturing: Trends and issues

A “slice method” is adopted to calculate the time-varying mesh stiffness (TVMS) of helical gear pairs, where the tooth is divided into many individual sliced spur gears along the tooth width, and the TVMS of helical gear pairs is obtained by accumulating the TVMS of the sliced spur gear pairs. Based on the slice method, an improved analytical method (IAM) is proposed to calculate TVMS of the helical gear pairs. The proposed method is also verified by comparing TVMS obtained from IAM with that obtained from references and the finite element method. Based on the proposed IAM, the effects of the helix angle, gear width, modification coefficient and friction coefficient on mesh characteristics are also discussed. The results show that the total contact ratio of helical gear changes under different helix angles and gear tooth widths, and the fluctuation of mesh stiffness will reduce when the overlap contact ratio approaches an integer. Meanwhile, addendum modifications can not only change the total contact ratio but also affect the mean mesh stiffness of gear pairs. Furthermore, not only will the friction coefficients affect the mean mesh stiffness, and it can lead to an abrupt change of TVMS in double-teeth engagement region.

An improved analytical method for calculating time-varying mesh stiffness of helical gears

https://ntrs.nasa.gov/api/citations/20030062134/downloads/20030062134.pdf

Modified involute helical gears: computerized design, simulation of meshing and stress analysis

The demand of large-sized spiral bevel gears has increased in recent years and hereafter the demand may increase more and more. The large-sized spiral bevel gears with equi-depth teeth are usually manufactured based on Klingelnberg cyclo-palloid system. In this paper, the tooth contact pattern of large-sized spiral bevel gears in this system are investigated analytically and experimentally. First, the tooth contact pattern and transmission errors of such gears are analyzed. The analysis method is based on simultaneous generations of tooth surface and simulations of meshing and contact. Next, the large-sized spiral bevel gears are manufactured and the tooth contact pattern of these gears is investigated experimentally. Moreover, the real tooth surfaces are measured using a coordinate measuring machine and the tooth flank form errors are detected using the measured coordinates. It is possible to analyze the tooth contact patterns of the spiral bevel gears with consideration of the tooth flank form errors expressing the errors as polynomial equations. Finally, the influence of alignment errors due to assembly on the tooth contact pattern is also investigated analytically and experimentally. These analyzed results were compared with experimental ones. As a result, two results showed a good agreement.Copyright © 2009 by ASME

Analytical and Experimental Tooth Contact Pattern of Large-Sized Spiral Bevel Gears in Cyclo-Palloid System

https://cyberleninka.org/article/n/211500.pdf

Method for remanufacturing large-sized skew bevel gears using CNC machining center

Tooth Contact Analysis and Manufacture on Multitasking Machine of Large-Sized Straight Bevel Gears With Equi-Depth Teeth

Straight bevel gears are usually manufactured with various machines and systems, and the tooth profiles are produced by grinding or machining by means of a tool with many cutting edges. In recent years, the straight bevel gear has been manufactured by an end mill using a computer numerical control (CNC) milling machine because the use of the auxiliary apparatus, special cutters, and special machine tools is not needed. Using this method, the gear manufacturing with high accuracy is an important problem. In this paper, the coordinate measurement of the straight bevel gear manufactured in this method is performed and the gear accuracy is evaluated. The tooth profiles of the straight bevel gear generated by a quasi-complementary crown gear instead of a conventional complementary crown gear are introduced. For this study, the tooth profiles of the straight bevel gear were modeled using a 3D computer-aided design system and the gear was manufactured by an end mill using a CNC milling machine based on a computer-aided manufacturing process. Afterward, the coordinates of many points on the gear tooth surfaces were measured at random using a coordinate measuring machine. This coordinate measurement provides the information about the factors related to the gear accuracy such as pressure angle, tooth angle error, workpiece setting angle, apex to back, and so on. Therefore, the values of the above factors were estimated and were compared with the theoretical ones, respectively.

Kazumasa Kawasaki

Papers

Modified involute helical gears: computerized design, simulation of meshing and stress analysis

Analytical and Experimental Tooth Contact Pattern of Large-Sized Spiral Bevel Gears in Cyclo-Palloid System

Method for remanufacturing large-sized skew bevel gears using CNC machining center

Tooth Contact Analysis and Manufacture on Multitasking Machine of Large-Sized Straight Bevel Gears With Equi-Depth Teeth

Accuracy Measurement and Evaluation of Straight Bevel Gear Manufactured by End Mill Using CNC Milling Machine