A Novel Finish Hobbing Methodology for Longitudinal Crowning of a Helical Gear With Twist-Free Tooth Flanks by Using Dual-Lead Hob Cutters

2014 ◽  
Author(s):  
Van-The Tran ◽  
Ruei-Hung Hsu ◽  
Chung-Biau Tsay
Keyword(s):  
Computer Simulation ◽  
Longitudinal Direction ◽  
Helical Gear ◽  
Tooth Profile ◽  
Second Order ◽  
Order Function ◽  
Helical Gears ◽  
Pressure Angle ◽  
Dual Lead ◽  
Tooth Flank

In the gear finish hobbing process, to obtain a twist-free tooth flank of helical gears, a novel hobbing method for longitudinal crowning is proposed by applying a new hob’s diagonal feed motion with a dual-lead hob cutter. Wherein the hob’s diagonal feed motion is set as a second order function of hob’s traverse movement and tooth profile of hob cutter is modified in a dual-lead form with pressure angle changed in it’s longitudinal direction. The proposed method is verified by using two computer simulation examples to compare topographies of the crowned work gear surfaces hobbed by the standard and dual-lead rack cutters. The results reveal the superiority of the proposed novel finish hobbing method.

Tooth Contact Analysis for a Double-Crowned Involute Helical Gear With Twist-Free Tooth Flanks Generated by Dual-Lead Hob Cutters

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Van-The Tran ◽  
Ruei-Hung Hsu ◽  
Chung-Biau Tsay
Keyword(s):  
Computer Simulation ◽  
Longitudinal Direction ◽  
Helical Gear ◽  
Contact Analysis ◽  
Tooth Contact Analysis ◽  
Order Function ◽  
Transmission Errors ◽  
Gear Manufacturing ◽  
Simulation Results ◽  
Dual Lead

To double-crown an involute helical gear, a hobbing method is proposed by setting the hob's diagonal feed motion as a second-order function of hob's traverse movement and modifying the tooth profile of hob cutter into a dual-lead form with pressure angle changed in its longitudinal direction. Merits of the proposed double-crowning method are also verified by using three computer simulation examples to illustrate and compare the topographies of tooth flanks, contact ellipses, and transmission errors under various assembly errors of the double-crowned gear pairs with those produced by using the conventional modified hob cutter and dual-lead hob cutter. Computer simulation results reveal the advantages of the proposed hobbing method for involute helical gear manufacturing.

Tooth Contact Analysis of Longitudinal Cycloidal-Crowned Helical Gears With Circular Arc Teeth

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
Wei-Shiang Wang ◽  
Zhang-Hua Fong
Keyword(s):  
Gear Tooth ◽  
Longitudinal Direction ◽  
Transmission Error ◽  
Helical Gear ◽  
Contact Analysis ◽  
Tooth Contact Analysis ◽  
Tooth Contact ◽  
Circular Arc ◽  
Tooth Flank ◽  
Assembly Error

This paper proposes a new type of double-crowned helical gear that can be continuously cut on a modern Cartesian-type hypoid generator with two face-hobbing head cutters and circular-arc cutter blades. The gear tooth flank is double crowned with a cycloidal curve in the longitudinal direction and a circular arc in the profile direction. To gauge the sensitivity of the transmission errors and contact patterns resulting from various assembly errors, this paper applies a tooth contact analysis technique and presents several numerical examples that show the benefit of the proposed double-crowned helical gear set. In contrast to a conventional helical involute gear, the tooth bearing and transmission error of the proposed gear set are both controllable and insensitive to gear-set assembly error.

Manufacturing helical gears with double-crowning and twist-free tooth flanks using a variable pressure angle shaving cutter

2017 ◽  
Vol 233 (1) ◽  
pp. 77-86 ◽  
Author(s):  
Ruei-Hung Hsu ◽  
Yu-Ren Wu ◽  
Van-The Tran
Keyword(s):  
Longitudinal Direction ◽  
Variable Pressure ◽  
Helical Gears ◽  
Numerical Examples ◽  
Pressure Angle ◽  
The Cross

For a parallel gear shaving process, the tooth flanks of a shaved work gear surface are longitudinally crowned using an auxiliary crowning mechanism. However, the flanks are only crowned in the longitudinal direction and not in the cross-profile direction so there is a natural twist on the shaved work gear surfaces. A new shaving method for double-crowning that has no natural twist in the tooth flanks on the work gear surfaces is proposed, which uses a variable pressure angle shaving cutter in a parallel gear shaving process. Three numerical examples are presented to verify the merits of the proposed shaving method. The tooth flanks are crowned in both the cross-profile and the longitudinal directions, and natural twists in the shaved tooth flanks are reduced significantly.

Modal Analysis and Parameters Research of Internal Helical Gears Based on AWE

2011 ◽  
Vol 86 ◽  
pp. 904-907 ◽  
Author(s):  
Yan Jun Gong ◽  
Xue Yao Wang ◽  
Han Zhao ◽  
Kang Huang
Keyword(s):  
Modal Analysis ◽  
Natural Frequency ◽  
Helix Angle ◽  
Helical Gear ◽  
Vibration Characteristics ◽  
Helical Gears ◽  
Pressure Angle ◽  
Number Of Teeth ◽  
Gear Change

The paper conducted a modal analysis of an internal helical gear based on AWE, and obtained its first 6 order natural frequency. Then the paper analyzed the influence of its parameters on the vibration characteristics of the internal helical gear, found that if the helix angle, the normal module, the number of teeth of the internal helical gear change, its vibration characteristics will change, but the change of the pressure angle doesn’t influence its vibration characteristics.

Design of Planetary Gear Reducer with Double Circular-Arc Helical Gear

2012 ◽  
Vol 152-154 ◽  
pp. 1595-1600 ◽  
Author(s):  
Chin Yu Wang
Keyword(s):  
Convex Combination ◽  
Planetary Gear ◽  
Gear Ratio ◽  
Helical Gear ◽  
Tooth Profile ◽  
National Standard ◽  
Reduction Gear ◽  
Circular Arc ◽  
Pressure Angle ◽  
Minimum Number

The two gears of the double circular-arc helical gear is a mesh of a concave/convex combination. Because the curvature is close to each other, the strength also increased and thus, it is often used in heavily-loaded workplaces. The national standard for double circular-arc helical gear (ex., GB12759-91) is based on the size of the gear module to design its tooth profile. This shows that tooth geometric-related designs are quite complicated. If the effect of the different pressure angle parameter is considered, we would be unable to conduct relevant studies for the original standard formula with a double circular-arc helical gear set at a pressure angle of 24°. Firstly, this paper would redefine a new double circular-arc helical gear according to the discontinuousness tooth profile molded line of the double circular-arc helical gear and unchangeable pressure angle and explain the improvements in the design and stress analysis of the tooth especially since the double circular-arc helical gear has no limitation in the minimum number of teeth. Thus, the decrease in the driving gears’ number of module and can further increase the reduction gear ratio. For heavily-loaded planetary gear reducer, it’s quite obvious in the miniaturizing and high torque superiority. This paper also used certain winch’s speed reducer as example to explain that the change of the pressure angle can reduce contact stress by 3%~40% and also enhances the torque ability by 3%~40%.

Laser Holographic Measurement of Tooth Flank Form of Cylindrical Involute Gear: Part 2 — For Helical Gear Tooth

1992 ◽  
Author(s):  
H. Fujio ◽  
A. Kubo ◽  
S. Tochimoto ◽  
H. Hanaki ◽  
S. Saitoh ◽  
...  
Keyword(s):  
Gear Tooth ◽  
Measuring Method ◽  
Helix Angle ◽  
Helical Gear ◽  
Helical Gears ◽  
Error Surface ◽  
Tooth Flank ◽  
Form Deviation ◽  
Laser Holography ◽  
Holographic Measurement

Abstract The interferometry using laser holography is applied to measure the form deviation of tooth flank of involute helical gears. One problem of this method is that the increase of helix angle reduces the region of the flank to which the laser beam can irradiate at a same time. To solve this problem, following method is developed: The objective tooth flank is divided into some regions, and the interferometry measurement is worked out for each region. The measured values for the form deviation of each region of the tooth flank are transformed to the values on the plane of action of this gear. These values for each region of the tooth flank are then concatenated successively until they result the curved surface for the form deviation of the whole tooth flank of the helical gear. The error surface of the tooth flank of helical gear obtained by this procedure is compared with that of conventional measuring method using contacting stylus.

Laser Interferometric Measuring Method of Involute Artifact and Stabilization of Measurement

2011 ◽  
Vol 5 (2) ◽  
pp. 144-149
Author(s):  
Masaharu Komori ◽  
◽  
Fumi Takeoka ◽  
Aizoh Kubo ◽  
Hiroshige Fujio ◽  
...  
Keyword(s):  
Gear Tooth ◽  
Measuring Method ◽  
Tooth Profile ◽  
National Standard ◽  
Helical Gears ◽  
Involute Gears ◽  
Measuring Machine ◽  
Form Quality ◽  
Tooth Flank ◽  
Laser Interferometric

Vibration and noise are serious problems with involute spur and helical gears used, e.g., in drivetrains of vehicles such as automobiles. The gear tooth flank form of micrometer order markedly affects gear vibration and noise; therefore, the tooth flank form quality must be strictly controlled to maximize gear performance. Tooth profile measuring machines used in calibration for form error inspection of involute gears usually use an involute artifact, which itself must be calibrated highly accurately. However, it is typically difficult for current tooth profile measuring machine using contact stylus to calibrate the involute artifact with a high accuracy while satisfying traceability to a national standard. A highly precise and traceable measuring technology for the involute artifact is therefore required. The direct measurement of the involute artifact we propose uses a laser interferometer, whose measurement stability is confirmed in experiments measuring the detailed form of an involute tooth flank.

Gear Flank Modification Using a Variable Lead Grinding Worm Method on a Computer Numerical Control Gear Grinding Machine

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Zhang-Hua Fong ◽  
Gwan-Hon Chen
Keyword(s):  
Rotation Angle ◽  
Helical Gear ◽  
Numerical Control ◽  
Helical Gears ◽  
Numerical Examples ◽  
Gear Grinding ◽  
Helical Angle ◽  
Grinding Machines ◽  
Grinding Machine ◽  
Tooth Flank

Tooth crowning of a ground helical gear is usually done by adjusting the radial feed with respect to the axial feed of the grinding worm on the modern CNC gear grinding machine. However, when the amount of crowning and the helical angle of the gear are large, this method always results in a twisted tooth flank. Hence, in this paper, we propose a tooth flank crowning method for helical gears, which uses a diagonal (combined tangential and axial) feed on a grinding machine with a variable lead grinding worm (VLGW) obtained by adjusting the axial feed of the dressing disk with respect to the rotation angle of the grinding worm. Since all the required corrective motions for the proposed VLGW method are existing CNC controlled axes on modern gear grinding machines, it can easily be implemented without extra cost to modify the grinder hardware. Three numerical examples are presented to show the validation of the proposed method and its ability to reduce tooth flank twist even in the case of a large helical angle, with a particularly significant reduction on a crowned helical gear.

Stress Concentration factor Analysis of Helical Gear Drives with Asymmetric Teeth Profiles

2018 ◽  
Vol 24 (5) ◽  
pp. 14
Author(s):  
Mohammad Qasim Abdullah ◽  
Mohammed Abdulaal Kadum
Keyword(s):  
Stress Concentration ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Bending Strength ◽  
Spur Gear ◽  
Helical Gear ◽  
Tooth Profile ◽  
Bending Stress ◽  
Pressure Angle ◽  
Side Pressure

This study investigates the influence of asymmetric involute teeth profiles for helical gears on the bending stress. Theoretically, bending stress has been estimated in spur involute gears which have symmetric teeth profile by based on the Lewis, 1892 equation. Later, this equation is developed by, Abdullah, 2012. to determine the effect of an asymmetric tooth profile for the spur gear on the bending stress. And then these equations are applied with stress concentration factor once for symmetric and once other for asymmetric teeth profile. In this paper, the bending stresses for various types of helical gear with various types of asymmetric teeth profile are calculated numerically for defined the stress concentration factor. The numerical solution based on the finite element method technique which that done by using the software simulation SolidWorks 2016. The results of this study indicate that the helical gear drive with asymmetric teeth profile having 'loaded side pressure angle' of ( ) and 'unloaded side pressure angle' of ( ) is better than a helical gear with standard teeth profile having pressure angle of ( ) from the regarding of tooth bending strength. Also, notes that the great enhancement in the results of maximum tooth bending stress for modified involute of tooth profile compared with the standard teeth profile. In addition to, predict the equation of stress concentration factor which is a function of both unloaded side pressure angle and helix angle and then it used with Abdullah equation for to determine the nominal stresses in the root fillet.  

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