Analytical Investigation of Radiated Noise for a Shaft-Bearing-Plate System Due to the Excitation of Helical Gears

2007 ◽  
Author(s):  
Chan Il Park
Keyword(s):  
Analytical Investigation ◽  
Helical Gear ◽  
Modal Testing ◽  
Housing System ◽  
Transfer Matrices ◽  
Helical Gears ◽  
Radiated Noise ◽  
Bearing Plate ◽  
The Moment ◽  
Mass Spring

Helical gears excite their housing system through forces and moments of bearings and then radiate noise. If noise is to be reduced, the contribution of noise to the gear housing due to the force and the moment must be determined. This work analytically investigated the radiated noise of a helical gear-housing system due to the excitation of helical gears. The helical gear-housing system consisted of gears, shafts, bearings, housings, and accessories. The gears were modeled as a 12-degree of freedom mass-spring-damper system; the shaft was modeled as a rod, a beam, and a torsional shaft so that the force and the moment were transmitted; and the gear housing was modeled as a clamped circular plate with viscous damping. The modeling of this system used transfer matrices for helical gears, shafts, and bearings. Damping for both the bearings and the plate were obtained by modal testing. An analysis of forced vibration of assembled transfer matrices produced a transmission of vibration. For the evaluation of noise, sound pressure from the plate due to the force and the moment in both radial and tangential directions was analytically derived by the Rayleigh integral. The analytical derivation and parameters from the experiment were applied to an analysis of noise for the two sets of helical gears with differing gear ratios. The analysis showed that the moment excitation in both helical gears contributed more to the noise of the plate than axial force excitation.

Analytical Procedure for Prediction of Radiated Noise From a Gear-Shaft-Plate System

2000 ◽  
Author(s):  
Chan Il Park
Keyword(s):  
Circular Plate ◽  
Analytical Procedure ◽  
Housing System ◽  
Single Degree Of Freedom ◽  
Gear Noise ◽  
Radiated Noise ◽  
Gear Mesh ◽  
Single Degree ◽  
The Moment ◽  
Mass Spring

Abstract In order to predict the gear noise, a simplified model of gear-shaft-housing system is studied. The gear is modeled as a single degree of freedom mass-spring-damper system. The shaft-housing system is modeled as a clamped circular plate connected with a beam. The moment components of the beam excited by the gear mesh force are considered in the calculation of the plate vibration and radiated noise. The displacements of the clamped circular plate due to the r-direction moment and θ-direction moment are analytically derived. Radiated noise from the plate is also derived using Rayleigh integral. Using the derived results, the numerical examples are given.

The Effect of Tooth Wear on the Dynamic Transmission Error of Helical Gears with Smaller Number of Pinion Teeth

2014 ◽  
Vol 657 ◽  
pp. 649-653 ◽  
Author(s):  
Virgil Atanasiu ◽  
Cezar Oprişan ◽  
Dumitru Leohchi
Keyword(s):  
Dynamic Contact ◽  
Tooth Wear ◽  
Transmission Error ◽  
Analytical Investigation ◽  
Helical Gear ◽  
Wear Depth ◽  
Contact Ratio ◽  
Mesh Stiffness ◽  
Helical Gears ◽  
Dynamic Transmission Error

The paper presents an analytical investigation of the effect of the tooth wear on the dynamic transmission error of helical gear pairs with small number of pinion teeth. Firstly, the dynamic analysis is conducted to investigate only the effect of the time-varying mesh stiffness on the variation of dynamic transmission error along the line of action. Then, the tooth wear effect on the dynamics of helical gear with small number of pinion teeth is being researched. In the analysis, instantaneous dynamic contact analysis is used in wear depth calculations. A comparative study was performed to investigate the relation between total contact ratio, mesh stiffness and dynamic transmission error of helical gear pairs with small number of teeth.

scholarly journals Vibro-Acoustical Sensitivities of Stiffened Aircraft Structures Due to Attached Mass-Spring-Dampers with Uncertain Parameters

Aerospace ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 174
Author(s):  
Johannes Seidel ◽  
Stephan Lippert ◽  
Otto von Estorff
Keyword(s):  
System Response ◽  
Fuzzy Arithmetic ◽  
Parameter Uncertainties ◽  
Excitation Spectra ◽  
Radiated Noise ◽  
Linking Elements ◽  
Manufacturing Tolerances ◽  
Suitable Framework ◽  
Mass Spring ◽  
The Impact

The slightest manufacturing tolerances and variances of material properties can indeed have a significant impact on structural modes. An unintentional shift of eigenfrequencies towards dominant excitation frequencies may lead to increased vibration amplitudes of the structure resulting in radiated noise, e.g., reducing passenger comfort inside an aircraft’s cabin. This paper focuses on so-called non-structural masses of an aircraft, also known as the secondary structure that are attached to the primary structure via clips, brackets, and shock mounts and constitute a significant part of the overall mass of an aircraft’s structure. Using the example of a simplified fuselage panel, the vibro-acoustical consequences of parameter uncertainties in linking elements are studied. Here, the fuzzy arithmetic provides a suitable framework to describe uncertainties, create combination matrices, and evaluate the simulation results regarding target quantities and the impact of each parameter on the overall system response. To assess the vibrations of the fuzzy structure and by taking into account the excitation spectra of engine noise, modal and frequency response analyses are conducted.

Gear transmission error outside the normal path of contact due to corner and top contact

1999 ◽  
Vol 213 (4) ◽  
pp. 389-400 ◽  
Author(s):  
R. G. Munro ◽  
L Morrish ◽  
D Palmer
Keyword(s):  
Dynamic Test ◽  
Theoretical Models ◽  
Transmission Error ◽  
Helical Gear ◽  
Gear Transmission ◽  
The Novel ◽  
Transmission Systems ◽  
Helical Gears ◽  
Tooth Stiffness ◽  
Top Contact

This paper is devoted to a phenomenon known as corner contact, or contact outside the normal path of contact, which can occur in spur and helical gear transmission systems under certain conditions. In this case, a change in position of the driven gear with respect to its theoretical position takes place, thus inducing a transmission error referred to here as the transmission error outside the normal path of contact (TEo.p.c). The paper deals with spur gears only, but the results are directly applicable to helical gears. It systematizes previous knowledge on this subject, suggests some further developments of the theory and introduces the novel phenomenon of top contact. The theoretical results are compared with experimental measurements using a single flank tester and a back-to-back dynamic test rig for spur and helical gears, and they are in good agreement. Convenient approximate equations for calculation of TEo.p.c suggested here are important for analysis of experimental data collected in the form of Harris maps. This will make possible the calculation of tooth stiffness values needed for use in theoretical models for spur and helical gear transmission systems.

scholarly journals Enhanced application limits for crossed helical gearboxes using new geometries for smaller sliding paths or smaller contact pressures

2019 ◽  
Vol 287 ◽  
pp. 01010
Author(s):  
Christoph Boehme ◽  
Dietmar Vill ◽  
Peter Tenberge
Keyword(s):  
Calculation Method ◽  
Helix Angle ◽  
Helical Gear ◽  
Design Parameters ◽  
Helical Gears ◽  
Positive Effects ◽  
Tooth Stiffness ◽  
Lubrication Condition ◽  
Overlap Ratio ◽  
Helical Gear Pair

Crossed-axis helical gear units are used as actuators and auxiliary drives in large quantities in automotive applications such as window regulators, windscreen wipers and seat adjusters. Commonly gear geometry of crossed helical gears is described with one pitch point. This article deals with an extended calculation method for worm gear units. The extended calculation method increases the range of solutions available for helical gears. In general, for a valid crossed helical gear pair, the rolling cylinders do not have to touch each other. In mass production of many similar gears, individual gears can be reused because they can be paired with other centre distances and ratios. This also allows the use of spur gears in combination with a worm, making manufacturing easier and more efficient. By selecting design parameters, for example the axis crossing angle or the helix angle of a gear, positive effects can be achieved on the tooth contact pressure, the overlap ratio, the sliding paths, the lubrication condition, the tooth stiffness and, to a limited extent, on the efficiency of the gearing. It can be shown that for involute helical gears, in addition to the known insensitivity of the transmission behaviour to centre distance deviations, there is also insensitivity to deviations of the axis crossing angle. This means that installation tolerances for crossed helical gearboxes can be determined more cost-effectively.

Calculation of Meshing Efficiency of Helical Gear Based on Double Integral Method

2016 ◽  
Vol 693 ◽  
pp. 458-462
Author(s):  
D.G. Chang ◽  
F. Shu ◽  
X.B. Chen ◽  
Y.J. Zou
Keyword(s):  
Experimental Data ◽  
Coordinate System ◽  
Theoretical Basis ◽  
Integral Method ◽  
Helical Gear ◽  
Design Parameters ◽  
Double Integral ◽  
Rectangular Coordinate System ◽  
Helical Gears ◽  
Theoretical Results

The meshing efficiency of helical gear transmission is calculated by using the method of double integral. The external involute helical gear meshing is taken and the model of helical gears is simplified by the idea of differential. The instantaneous efficiency equation of a meshing point is derived, and further more the rectangular coordinate system of meshing zone of helical gears is established. The average meshing efficiency of helical gears is achieved by using double integral method. Then, the influence of design parameters is studied and the efficiency formula is verified by comparing the theoretical results with relevant experimental data, which can provide a theoretical basis for decide the design parameters.

The Investigation of the Travelling Wave Resonance of Driven Helical Gear

1993 ◽  
Author(s):  
Shijun Qiu ◽  
Min Xu
Keyword(s):  
Travelling Wave ◽  
Helical Gear ◽  
Exciting Force ◽  
Resonant Vibrations ◽  
Damping Force ◽  
Helical Gears ◽  
Wave Resonance ◽  
Work Done ◽  
Component Force ◽  
Transmission Test

The main vibration type gearing in modern aeroengine transmission is the travelling wave vibration which is divided into two kinds: the forward travelling wave vibration and the backward travelling wave vibration. If the frequency of vibration exciting force, which comes from the meshing of a set of helical gears, is the same as the frequency of travelling wave resonance, the dangerous resonant vibration will take place. However both of forward and backward travelling wave resonance can not be excited as easily. The results of an aeroengine transmission test indicate that forward travelling wave resonant vibrations are more easily excited to the driven helical gear and more dangerous. The work done by the component force, which is generated because of the angle of travelling wave vibration, on the driven helical gear, work done on the forward travelling wave vibration is positive and the backward travelling wave vibration is negative. In other words, for backward travelling wave vibration the induced force acts as a damping force, but for forward travelling wave vibration the induced force acts as a self–exciting force. Therefore it is more dangerous to driven helical gear when forward travelling wave vibration appears.

Manufacturing method of double-helical gears using CNC machining center

2015 ◽  
Vol 230 (7-8) ◽  
pp. 1149-1156 ◽  
Author(s):  
Kazumasa Kawasaki ◽  
Isamu Tsuji ◽  
Hiroshi Gunbara
Keyword(s):  
Machine Tools ◽  
Helical Gear ◽  
Cnc Machining ◽  
Tooth Surface ◽  
Design System ◽  
Helical Gears ◽  
Manufacturing Method ◽  
Machining Center ◽  
Computer Aided ◽  
Cnc Machining Center

Double-helical gears are usually manufactured using special type of machine tools, such as gear hobbing and shaping machines. In this paper, a manufacturing method of double-helical gears using a CNC machining center instead of the special type of machine tools is proposed. This manufacturing method has the following advantages: (i) the tooth surfaces can be modified arbitrarily, (ii) all we have to do in gear machining is only one machine setting, (iii) the hole and blank diameter and so on except the tooth surface can be also machined, and (iv) the auxiliary apparatus, special type of tools, and special type of machine tools are not needed. For this study, first the tooth profiles of the double-helical gear were modelled using a 3D computer-aided design system and the gear was machined using a CNC machining center based on a computer-aided manufacturing system. Next, the profile deviations, helix deviations, pitch deviations, and surface roughnesses of the manufactured double-helical gears were measured. Afterwards, the relationship between the tool wear and life time of the end mill were made clear. Finally, this manufacturing method was applied to the gears for a double-helical gear pump. As a result, the validity and effectiveness of the manufacturing method of double-helical gears using a CNC machining center were confirmed.

Four-Order Parabolic Transmission Error Design of Helical Gear Based on Meshing Area

2013 ◽  
Vol 842 ◽  
pp. 410-414
Author(s):  
Jian Jun Yang ◽  
Jian Jun Wang
Keyword(s):  
Contact Stress ◽  
Transition Point ◽  
Design Method ◽  
Transmission Error ◽  
Helical Gear ◽  
Transmission Curve ◽  
Tooth Contact Analysis ◽  
Contact Conditions ◽  
Helical Gears ◽  
Alignment Errors

In the paper, a new transmission error design method for helical gears is presented. According to transition point position of the contact area in one meshing cycle, the proposed four-order transmission curve is able to diminish contact stress and edge contact, decrease transmission error as well. Tooth contact analysis is used to simulate contact conditions of helical gear driver with four-order parabolic modification curve. The results show that the meshing area is non-sensitive to the alignment errors.

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