scholarly journals Computer-Aided Design of High-Contact-Ratio Gears for Minimum Dynamic Load and Stress

1993 ◽  
Vol 115 (1) ◽  
pp. 171-178 ◽  
Author(s):  
Hsiang Hsi Lin ◽  
Chinwai Lee ◽  
F. B. Oswald ◽  
D. P. Townsend
Keyword(s):  
Dynamic Load ◽  
Computer Aided Design ◽  
Numerical Procedure ◽  
Tooth Profile ◽  
Lower Sensitivity ◽  
Contact Ratio ◽  
Profile Modification ◽  
Parabolic Profile ◽  
Profile Design ◽  
Optimum Profile

This paper presents a numerical procedure for minimizing dynamic effects on high-contact-ratio gears by modification of the tooth profile. The paper examines and compares both linear and parabolic tooth profile modifications of high-contact-ratio gears under various loading conditions. The effects of the total amount of modification and the length of the modification zone were systematically studied at various loads and speeds to find the optimum profile design for minimizing the dynamic load and the tooth bending stress. Parabolic profile modification is preferred over linear profile modification for high-contact-ratio gears because of its lower sensitivity to manufacturing errors. For parabolic modification a greater amount of modification at the tooth tip and a longer modification zone are required. Design charts are presented for high-contact-ratio gears with various profile modifications operating under a range of loads. A procedure is illustrated for using the charts to find the optimum profile design.

scholarly journals Modification Method of Tooth Profile of Locomotive Traction Gear Based on Rodent Arm Variation

2019 ◽  
Vol 48 (1) ◽  
pp. 89-97
Author(s):  
Lei Lei ◽  
Haichun Ding ◽  
Liang Xuan ◽  
Meichao Qin ◽  
Siyuan Tian ◽  
...  
Keyword(s):  
Power Transmission ◽  
Tooth Profile ◽  
Moment Arm ◽  
Contact Ratio ◽  
Profile Modification ◽  
Tooth Profile Modification ◽  
Element Simulation ◽  
Load Carrying ◽  
The Moment ◽  
Universal Rule

Locomotive traction gear is the key component to power transmission and speed control in locomotive transmission system, which plays an important role in locomotive running speed and load-carrying torque. Considering that there is not universal rule for the method of modification of locomotive gear at present, in this paper, the tooth profile modification is considered with the combination of the increased contact ratio and the variation of the moment arm of action. Based on the principle of modification, according to the load direction after modification, the change rule of moment arm of action after modification is determined, and the interval range of tooth profile modification is also determined. Taking a certain locomotive traction gear as an example, the results obtained through the method of modification which based on combining moment arm of action variation with the increase of contact ratio and the method based on the traditional empirical formula are compared through finite element simulation respectively, on this account to verify the superiority of the theory of modification, which has important theoretical significance for profile modification of locomotive traction gear.

Influence of Linear Profile Modification and Loading Conditions on The Dynamic Tooth Load and Stress of High-Contact-Ratio Spur Gears

1991 ◽  
Vol 113 (4) ◽  
pp. 473-480 ◽  
Author(s):  
Chinwai Lee ◽  
Hsiang Hsi Lin ◽  
Fred B. Oswald ◽  
Dennis P. Townsend
Keyword(s):  
Computer Simulation ◽  
Contact Stress ◽  
Dynamic Load ◽  
Applied Load ◽  
Gear Tooth ◽  
Load Force ◽  
Loading Conditions ◽  
Contact Ratio ◽  
Profile Modification ◽  
Root Stress

This paper presents a computer simulation for the dynamic response of high-contact-ratio spur gear transmissions. High contact ratio gears have the potential to produce lower dynamic tooth loads and minimum root stress but they can be sensitive to tooth profile errors. The analysis presented in this paper examines various profile modifications under realistic loading conditions. The effect of these modifications on the dynamic load (force) between mating gear teeth and the dynamic root stress is presented. Since the contact stress is dependent on the dynamic load, minimizing dynamic loads will also minimize contact stresses. This paper shows that the combination of profile modification and the applied load (torque) carried by a gear system has a significant influence on gear dynamics. The ideal modification at one value of applied load will not be the best solution for a different load. High-contact-ratio gears were found to require less modification than standard low-contact-ratio gears. High-contact-ratio gears are more adversely affected by excess modification than by under modification. In addition, the optimal profile modification required to minimize the dynamic load (hence the contact stress) on a gear tooth differs from the optimal modification required to minimize the dynamic root (bending) stress. Computer simulation can help find the design tradeoffs to determine the best profile modification to satisfy the conflicting constraints of minimizing both the load and root stress in gears which must operate over a range of applied loads.

Simulation of Accessory Drives Bevel Gears Dynamic Conditions

2014 ◽  
Author(s):  
Egor Kozharinov ◽  
Jury Temis
Keyword(s):  
Stress Concentration ◽  
Dynamic Load ◽  
Maximum Amplitude ◽  
Transmission Error ◽  
Tooth Profile ◽  
Bevel Gear ◽  
Principal Stresses ◽  
Disturbing Force ◽  
Profile Modification ◽  
Bevel Gears

Bevel gears of modern aviation motors operate at high rotation velocities and transmitted torques. High dynamic load in bevel mesh due to impact interaction of teeth in contact actuates gear rim oscillations. Coincidence of dynamic load frequency and bevel gear natural frequency of nodal diameter can cause oscillation amplitude grow and gear rim breakdown. By harmonic response analysis it is shown, that highest stresses in gear rim appears during gear oscillation by two or three nodal diameters. Gear root is a stress concentration in this case. In this paper methods of bevel gears dynamic behavior simulation are considered. A 3D solid dynamic model of bevel gear drive with transient contact interaction between pinion and gear by curvilinear teeth subject to tooth profile modification has been developed. An actuation was made by kinematic way by applying rotational velocity to driving pinion. A transmitted torque is applied to driven gear. An energy dissipation in gear material is considered in model. A transmission error of bevel gears depending on profile modification, transmitted torque and diaphragm stiffness is calculated. It is shown, that applying tooth profile modification helps to avoid stress concentration on teeth flank, decreases transmission error and derivatives of it’s function. As a result of calculation a function of disturbing force, actuating in gear mesh, dynamic transmission error and first principal stresses of gear crown face in time domain has been obtained. A spectral analysis of disturbing force and first principal stresses of gear rim is executed. As a result, it is shown, that gearing mesh is a source of poly-harmonic excitation of bevel gears. The maximum amplitude in contact force spectra is at frequency four times greater, than tooth frequency, and the maximum amplitude in first principal stresses of gear crown face spectra is at tooth frequency. Using a first principal stresses law of variation a new criterion of bevel gear rim strength is obtained.

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.

Effect of Tooth Profile Modifications on the Dynamics of High-Contact-Ratio Gears With Different Tooth Spacing Errors

2006 ◽  
Author(s):  
Hsiang H. Lin ◽  
Jing Liu
Keyword(s):  
Computer Simulation ◽  
Dynamic Analysis ◽  
Dynamic Performance ◽  
Tooth Profile ◽  
Dynamic Loads ◽  
Contact Ratio ◽  
Gear Dynamics ◽  
Profile Modification ◽  
Tooth Profile Modification

A computer simulation was conducted to investigate the effectiveness of profile modification for reducing dynamic loads in high-contact-ratio gears with different tooth spacing errors. The simulation examined varying amplitudes of spacing error and differences in the span of teeth over which the error occurs. The modification considered included both linear and parabolic tip relief. The dynamic analysis was performed using a revised version of a NASA gear dynamics code, modified to take into consideration the tooth spacing errors in the dynamic analysis. The findings of this study can be used to design robust tooth profile modification for improving dynamic performance of high-contact-ratio gear sets with different tooth spacing errors.

Effect of Contact Ratio on Spur Gear Dynamic Load With No Tooth Profile Modifications

1996 ◽  
Vol 118 (3) ◽  
pp. 439-443 ◽  
Author(s):  
Chuen-Huei Liou ◽  
Hsiang Hsi Lin ◽  
F. B. Oswald ◽  
D. P. Townsend
Keyword(s):  
Dynamic Load ◽  
Spur Gear ◽  
Tooth Size ◽  
Contact Ratio ◽  
Gear Dynamics ◽  
Wide Range ◽  
Gear Contact ◽  
Center Distance ◽  
Selection Of ◽  
Better Than

This paper presents a computer simulation showing how the gear contact ratio affects the dynamic load on a spur gear transmission. The contact ratio can be affected by the tooth addendum, the pressure angle, the tooth size (diametral pitch), and the center distance. The analysis presented in this paper was performed by using the NASA gear dynamics code DANST. In the analysis, the contact ratio was varied over the range 1.20 to 2.40 by changing the length of the tooth addendum. In order to simplify the analysis, other parameters related to contact ratio were held constant. The contact ratio was found to have a significant influence on gear dynamics. Over a wide range of operating speeds, a contact ratio close to 2.0 minimized dynamic load. For low-contact-ratio gears (contact ratio less than two), increasing the contact ratio reduced gear dynamic load. For high-contact-ratio gears (contact ratio equal to or greater than 2.0), the selection of contact ratio should take into consideration the intended operating speeds. In general, high-contact-ratio gears minimized dynamic load better than low-contact-ratio gears.

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