scholarly journals Study of the tooth contact for high contact ratio spur gears with long tip relief

2019 ◽  
Vol 287 ◽  
pp. 01004
Author(s):  
José I. Pedrero ◽  
Miguel Pleguezuelos ◽  
Miryam B. Sánchez
Keyword(s):  
Load Sharing ◽  
Transmission Error ◽  
Spur Gears ◽  
Contact Ratio ◽  
Tooth Contact ◽  
Gear Teeth ◽  
Profile Modification ◽  
Static Transmission Error ◽  
Tooth Pair

Profile modifications are commonly used to avoid shocks between meshing gear teeth produced by the delay of the driven gear, and the subsequent sooner start of contact, due to the teeth deflections. A suitable tip relief at the driven tooth shifts the start of contact to the proper location at the theoretical inner point of contact. The shape of the relief governs the loading curve of the tooth pair, while the length of relief determines the intervals in which this actual loading curve differs from the theoretical one of unmodified teeth. As at least one tooth pair should be in contact at the unmodified involute profile interval, the length of modification should be smaller than the length of the intervals of two pair tooth contact; otherwise, a shock at the end of contact of the previous pair is unavoidable. However this problem does not occur for high contact ratio spur gears, in which at least two couples of teeth are in contact at any moment. In this work, a study on the load sharing and the quasi-static transmission error for high contact ratio spur gears with long profile modification has been performed, and a model for the tooth contact has been developed.

scholarly journals An experimental method to measure gear tooth stiffness throughout and beyond the path of contact

2001 ◽  
Vol 215 (7) ◽  
pp. 793-803 ◽  
Author(s):  
R. G. Munro1 ◽  
D Palmer ◽  
L Morrish
Keyword(s):  
Gear Tooth ◽  
Contact Region ◽  
Transmission Error ◽  
Spur Gears ◽  
Contact Ratio ◽  
Extended Contact ◽  
Tooth Stiffness ◽  
Simplifying Assumptions ◽  
Tooth Pair ◽  
Usual Problem

A method is presented that allows the accurate measurement of the tooth pair stiffness of a pair of spur gears. The method reveals the stiffness behaviour throughout the full length of the normal path of contact and also into the extended contact region when tooth corner contact occurs. The method makes use of the properties of transmission error plots for mean and alternating components over a range of tooth loads (Harris maps). It avoids the usual problem when measuring tooth deflections that deflections of other test rig components are difficult to eliminate. Also included are predicted Harris maps for a pair of high contact ratio spur gears, showing the effects of various simplifying assumptions, together with a measured map.

Effect of profile modification on the performance of spur gears in isothermal mixed-EHL regime using load-sharing concept

2018 ◽  
Vol 233 (6) ◽  
pp. 936-948 ◽  
Author(s):  
Masoud Kimiaei ◽  
Saleh Akbarzadeh
Keyword(s):  
Wear Rate ◽  
Power Transmission ◽  
Elastohydrodynamic Lubrication ◽  
Load Sharing ◽  
Spur Gears ◽  
Gear Teeth ◽  
Profile Modification ◽  
Model Based ◽  
Mechanical Element ◽  
The Cost

Spur gears are one of the most important tools for power transmission in the industry and thus can be considered a key mechanical element. As a result of power transmission, gears might fail or experience wear and fatigue. So the improvement in the design and modification of tooth profile of gears can significantly reduce friction loss and wear of the gear teeth and therefore it increases the useful life, improves the quality, and reduces the cost. The purpose of this study is to show the influence of addendum modification on the tribological performance of spur gears which are operating in the mixed elastohydrodynamic lubrication. In this paper, a model based on the load-sharing concept is employed to study the effect of changing addendum modification on the performance of spur gears, the amount of wear rate, and the lubricant film thickness. To this end, a model based on the load-sharing concept is employed which takes the geometry and lubricant properties as input and predicts the friction coefficient, load carried by fluid film and asperities, efficiency, and wear rate as output.

Tooth Load Sharing in High-Contact Ratio Spur Gears

1985 ◽  
Vol 107 (1) ◽  
pp. 11-16 ◽  
Author(s):  
A. H. Elkholy
Keyword(s):  
Contact Stress ◽  
Applied Load ◽  
Normal Load ◽  
Closed Form Solution ◽  
Load Sharing ◽  
Form Solution ◽  
Spur Gears ◽  
Contact Ratio ◽  
Profile Modification ◽  
The Individual

A closed-form solution is presented for calculating the load sharing among meshing teeth in high contact ratio gearing (HCRG). The procedure is based upon the assumption that the sum of the tooth deflection, profile modification and spacing error at each of two or three pairs of contacts are all equal. It is also assumed that the sum of the normal loads contributed by each of two or three pairs of contacts is equal to the maximum normal load. Once the individual loads are determined, the tooth fillet stress, contact stress may be determined from the applied load and tooth geometry. An experimental example appears to verify the method.

scholarly journals Selection of Pressure Angle based on Dynamic Effects in Asymmetric Spur Gear with Fixed Normal Contact Ratio

2019 ◽  
Vol 69 (3) ◽  
pp. 303-310
Author(s):  
Benny Thomas ◽  
K. Sankaranarayansamy ◽  
S. Ramachandra ◽  
Suresh Kumar S.P.
Keyword(s):  
Gear Tooth ◽  
Transmission Error ◽  
Spur Gear ◽  
Dynamic Factor ◽  
Spur Gears ◽  
Contact Ratio ◽  
Normal Contact ◽  
Pressure Angle ◽  
Side Pressure ◽  
Static Transmission Error

Asymmetric spur gears are finding application in many fields including aerospace propulsion and automobile which demand unidirectional or relatively higher load on one side of the gear flank. Design intend to maximise the load carrying capacity of the drive side of asymmetric gear by increasing the pressure angle is achieved at the expense of coast side capacity. Multiple solution for coast to drive side pressure angle exist for a given contact ratio and each of these have relative merits and demerits. In the present work asymmetric spur gears of theoretically equal contact ratio as that of corresponding symmetric gears are selected to investigate the change in gear tooth static transmission error and dynamic behaviour with coast and drive side pressure angle. Study shows that dynamic factor of normal contact ratio asymmetric spur gears below resonance speed are relatively lower than corresponding symmetric gears of same module, contact ratio, number of teeth, coast side pressure angle and fillet radii. Results also show that, coast and drive side pressure angle can be suitably selected for a given contact ratio to reduce the single tooth and double tooth contact static transmission error and dynamic factor of asymmetric spur gears.

Optimum Profile Modifications for the Minimization of Static Transmission Errors of Spur Gears

1986 ◽  
Vol 108 (1) ◽  
pp. 86-94 ◽  
Author(s):  
M. S. Tavakoli ◽  
D. R. Houser
Keyword(s):  
Transmission Error ◽  
Spur Gears ◽  
Contact Ratio ◽  
Transmission Errors ◽  
Gear Mesh ◽  
Starting Point ◽  
Frequency Components ◽  
Design Loads ◽  
Static Transmission Error ◽  
Optimum Profile

A procedure for computing static transmission errors and tooth load sharing was developed for low and high contact ratio internal and external spur gears. A suitable optimization algorithm was used to minimize any combination of the harmonics of gear mesh frequency components of the static transmission error. Different combinations of tip and root relief may be used to achieve optimization. These include varying the starting point of relief and varying the magnitude of relief, and selecting the gear and/or the pinion teeth to be tip and/or root-relieved. Also, there exists an option for using either linear or parabolic relief. In addition to the presentation of optimal profile modifications, the effects of off-design loads, nonoptimum modifications, and random spacing errors are presented.

A Further Study on High Contact Ratio Spur Gears in Mesh With Double Scope Tooth Profile Modification

2007 ◽  
Author(s):  
Jiande Wang ◽  
Ian Howard
Keyword(s):  
Weight Ratio ◽  
Transmission Error ◽  
Tooth Profile ◽  
Spur Gears ◽  
Contact Ratio ◽  
Profile Modification ◽  
Tooth Profile Modification ◽  
Major Interest ◽  
Higher Power ◽  
Lower Transmission

Compared to the commonly used Low Contact Ratio Spur Gears (LCRG), High Contact Ratio Spur Gears (HCRG) can provide higher power to weight ratio, and can also achieve smoother running with lower Transmission Error (TE) variations. To achieve the benefits of High Contact Ratio Spur Gears (HCRG), its tolerance to manufacturing errors and elastic deformation has to be increased. After various attempts by previous researchers, double scope tooth profile modifications have been seen as being of major interest showing great potential for improvements in most applications. Research presented in this paper concentrated on providing further proofs and verifications on the topic by using modern numerical methods and comprehensive analysis. Additionally, a general Bulk Tooth Rotation (BTR) type tooth profile modification is introduced and applied to the High Contact Ratio Spur Gears (HCRG) in order to improve the tooth profile design and some common higher order analysis is shown allowing further comments to be made.

An analytical method to determine the influence of shape deviation on load distribution and mesh stiffness for spur gears

2002 ◽  
Vol 216 (10) ◽  
pp. 1005-1016 ◽  
Author(s):  
L D MacLennan
Keyword(s):  
Angular Displacement ◽  
Nodal Point ◽  
Load Sharing ◽  
Transmission Error ◽  
Spur Gears ◽  
Contact Ratio ◽  
Mesh Stiffness ◽  
Shape Deviation ◽  
Dimensional Finite Element ◽  
Medium Quality

A method for analysing the influence of profile errors upon load-sharing capabilities and mesh stiffness of spur gears is proposed. The analysis is based upon a static, two-dimensional finite element approach. The contacts between mating gear teeth are identified in the deformed state, and the nodal point density permits contact pressure distribution emulation for moderate to high load levels. In addition, artificial neural networks are employed for system identification in order to calculate load-sharing capabilities and mesh stiffness trends for low tooth load levels. The effect of tip relief on load-sharing properties is discussed. The contact force and the transmission error are simulated for two medium-quality spur gears where the profile and pitch errors are known. Experimental data validate the reliability of the approach. The contact ratio is shown to be highly load dependent due to profile and pitch errors. The discussion is focused upon the size of the area where the relation between torque and angular displacement is highly non-linear, i.e. load depending. Hence, the contact ratio is shown to be load depending due to geometrical errors, such as profile and pitch errors, in addition to material elasticity.

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