Analysis of gear noise and design for gear noise reduction

Kooyoung Yoon, Purdue University

Abstract

The area of gear dynamics and noise, which is the most underdeveloped area of gear design, has recently been the focus of many studies. The proper kinematic and geometric design of gears, the mathematical modeling of gear systems, and the analysis of vibration excitation of gears and gear systems are essential for a good design. This work presents a state-of-the-art review of gear noise, the general area of gear design for reducing noise, and practical approaches used for machinery noise reduction along with a summary of methods available for predicting gear noise in terms of the transmission error. A new method is proposed for reducing the vibration and noise of involute gears. The method is based on the use of cubic spline curves for gear tooth profile modification. The tooth profile is constrained to assume an involute shape during the loaded operation so that it ensures conjugate motion at all points along the line of action. The new profile is found to result in a more uniform static transmission error compared to the standard involute profile, thereby contributing to the improvement of the vibration and noise characteristics of the gear. The methodology is extended for the minimization of the transmission error in helical gears. Using the concept of optimal modification of the plane of action to generate the new tooth profile, the idea of a perfect plane of action of helical gears is introduced. The proposed method constitutes a general tooth correction method and makes the design, unlike other modification schemes presented in the literature, less complex, less sensitive to dynamic factors, and easier to manufacture while retaining the involute characteristics. A dynamic analysis of the gear drive with the involute tooth and the modified tooth profile (using cubic splines) is performed to establish the fact that a reduction in the transmission error reduces the gear vibration and noise due to smaller dynamic tooth loads during a meshing cycle. For this, first the tooth deformation is found and then the tooth dynamic load is determined for all reasonable speeds. A parameter study is also conducted to establish the superiority of the cubic spline (C.S.) based gear profile over the involute profile as well as those based on the use of linear and parabolic tip reliefs.

Degree

Ph.D.

Advisors

Rao, Purdue University.

Subject Area

Mechanical engineering|Automotive materials

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