Generation of the Anti-Twist Crowned Helical Gear by Modifying the Gear Rotation Angle in the Hobbing Process

2017 ◽  
Vol 749 ◽  
pp. 161-170
Author(s):  
Ruei Hung Hsu ◽  
Yu Ren Wu ◽  
Shih Sheng Chen
Keyword(s):  
Rotation Angle ◽  
Gear Tooth ◽  
Helical Gear ◽  
Gear Hobbing ◽  
Tooth Flank ◽  
Center Distance

In the gear-hobbing process, the work gear tooth flank is usually longitudinally crowned by varying the center distance between the hob and the work gear. Without crossed angle compensation, however, this center distance variation produces a twisted tooth flank on the work gear. This paper therefore proposes a methodology to reduce this tooth flank twist and achieve anti-twist in longitudinal crowning by modifying the gear rotation angle in the hobbing process which is practiced using a CNC hobbing machine with three synchronous axes.

Study on the Anti-Twist Helical Gear Tooth Flank With Longitudinal Tooth Crowning

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Van-The Tran ◽  
Ruei-Hung Hsu ◽  
Chung-Biau Tsay
Keyword(s):  
Rotation Angle ◽  
Gear Tooth ◽  
Nonlinear Function ◽  
Helical Gear ◽  
Tooth Flank

To attain an anti-twist helical gear tooth flank with longitudinal tooth crowning, a novel additional rotation angle is proposed for the work gear during its hobbing process. A congruous nonlinear function with two variables is proposed and supplemented to this additional rotation angle of work gear. Two numeral examples are presented to illustrate the effects of coefficients of the proposed nonlinear function on the twist and evenness of generated helical gear tooth flanks. The twist of the crowned helical tooth flank is reduced significantly by applying the proposed longitudinal crowning gear method.

A parameterized numerical method for generating discrete helical gear tooth surface allowing non-standard geometry

2008 ◽  
Vol 222 (6) ◽  
pp. 1033-1038 ◽  
Author(s):  
J Hedlund ◽  
A Lehtovaara
Keyword(s):  
Gear Tooth ◽  
Numerical Approach ◽  
Helical Gear ◽  
Tooth Surface ◽  
Tool Profile ◽  
Standard Geometry ◽  
Gear Manufacturing ◽  
Involute Gears ◽  
Gear Geometry ◽  
Tooth Flank

Gear analysis is typically performed using calculation based on gear standards. Standards provide a good basis in gear geometry calculation for involute gears, but these are unsatisfactory for handling geometry deviations such as tooth flank modifications. The efficient utilization of finite-element calculation also requires the geometry generation to be parameterized. A parameterized numerical approach was developed to create discrete helical gear geometry and contact line by simulating the gear manufacturing, i.e. the hobbing process. This method is based on coordinate transformations and a wide set of numerical calculation points and their synchronization, which permits deviations from common involute geometry. As an example, the model is applied to protuberance tool profile and grinding with tip relief. A fairly low number of calculation points are needed to create tooth flank profiles where error is <1 μm.

scholarly journals Generation of a double-crowned involute helical gear with twist-free tooth flanks by a CNC hobbing machine with three synchronous axes

2017 ◽  
Vol 39 (2) ◽  
pp. 97-108
Author(s):  
Van-The Tran
Keyword(s):  
Computer Simulation ◽  
Rotation Angle ◽  
Computer Numerical Control ◽  
Helical Gear ◽  
Numerical Control ◽  
Production Costs ◽  
Parabolic Curve ◽  
Transmission Errors ◽  
Simulation Results ◽  
Center Distance

In the conventional hobbing process, a double-crowned involute helical gear is generated by the hob cutter with parabolic-curve tooth profiles for the cross-profile crowning and varied the center distance between the hob and work gear for the longitudinal crowning. Therefore, to cut a double-crowned helical gear not only requires at least four synchronous axes and hob cutter regrinding (which increases production costs) but also induces twisted tooth flanks on the generated work gear. In this paper, I propose a hobbing method by applying a modified work gear rotation angle that enables double-crowning of involute helical gear's tooth flanks using a standard hob cutter and a computer numerical control (CNC) hobbing machine with only three synchronous axes. The proposed method has also verified by using two computer simulation examples to compare the meshing-conditions, contact ellipses, and transmission errors of the double-crowned gear pairs with that produced by applying the conventional hobbing method. Computer simulation results reveal the advantages of the proposed novel hobbing method.

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.

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.

scholarly journals Mathematical Model of Helical Gear Topography Measurements and Tooth Flank Errors Separation

2015 ◽  
Vol 2015 ◽  
pp. 1-10
Author(s):  
Huiliang Wang ◽  
Xiaozhong Deng ◽  
Jianhai Han ◽  
Jubo Li ◽  
Jianjun Yang
Keyword(s):  
Mathematical Model ◽  
Gear Tooth ◽  
Helical Gear ◽  
Tooth Surface ◽  
Geometrical Shape ◽  
Form Grinding ◽  
Polar Coordinate ◽  
Grinding Machine ◽  
Tooth Flank ◽  
Five Axis

During large-size gear topological modification by form grinding, the helical gear tooth surface geometrical shape will be complex and it is difficult for the traditional scanning measurement to characterize the whole tooth surface. Therefore, in order to characterize the actual tooth surfaces, an on-machine topography measurement approach is proposed for topological modification helical gears on the five-axis CNC gear form grinding machine that can measure the modified gear tooth deviations on the machine immediately after grinding. Combined with gear form grinding kinematics principles, the mathematical model of topography measurements is established based on the polar coordinate method. The mathematical models include calculating trajectory of the centre of measuring probe, defining gear flanks by grid of points, and solving coordinate values of topology measurement. Finally, a numerical example of on-machine topography measurement is presented. By establishing the topography diagram and the contour map of tooth error, the tooth surface modification amount and the tooth flank errors are separated, respectively. Research results can serve as foundation for topological modification and tooth surface errors closed-loop feedback correction.

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.

A Methodology for Longitudinal Tooth Flank Crowning of the Helical Gear on a CNC Honing Machine

2015 ◽  
Vol 1091 ◽  
pp. 53-62 ◽  
Author(s):  
Van The Tran ◽  
Ruei Hung Hsu ◽  
Chung Biau Tsay
Keyword(s):  
Heat Treatment ◽  
Treatment Process ◽  
Gear Tooth ◽  
Helical Gear ◽  
Heat Treatment Process ◽  
Gear Honing ◽  
Tooth Surfaces ◽  
Novel Method ◽  
Hard Finishing ◽  
Tooth Flank

The gear honing is the most economical way for hard finishing an involute helical gear after hobbing and heat treatment or after shaving and heat treatment. The gear honing can also be applied to the modification of gear tooth surfaces to compensate for the distortions that occur during heat treatment process. Most published papers on the technology of gear honing describes on the principle of generated gear surface. However, the longitudinal tooth flank crowning of a helical gear with honing has not been investigated yet. Therefore, in this paper, we proposed a novel method for longitudinal tooth flank crowning of work gear surfaces by setting a crossed angle between the honing cutter and work gear axes as a linear function of honing cutter's traverse feed in the honing process. A mathematical model for the tooth profile of work gear honed by a standard honing cutter is also established. Three numeral examples are presented to illustrate and verify the merits of the proposed gear honing method in longitudinal crowning.

Kinematic Optimization of a Modified Helical Gear Train

1997 ◽  
Vol 119 (2) ◽  
pp. 307-314 ◽  
Author(s):  
Shinn-Liang Chang ◽  
Chung-Biau Tsay ◽  
Ching-Huan Tseng
Keyword(s):  
Mathematical Model ◽  
Gear Tooth ◽  
Optimization Method ◽  
Helical Gear ◽  
Gear Train ◽  
Tooth Contact Analysis ◽  
Numerical Examples ◽  
Kinematic Optimization ◽  
Kinematic Errors ◽  
Center Distance

A mathematical model of a modified helical gear train (MHGT), manufactured with a practical hobbing machine using a curved-template guide, and which takes considerations of center-distance variation and axial misalignment into account, is developed. Tooth contact analysis (TCA) and kinematic errors of a MHGT due to mis-assembly are investigated. A multiple optimization method is applied to reduce the level of MHGT kinematic errors, and to investigate optimal gear tooth modifications. Computer simulation programs for TCA and optimization are also developed. Two numerical examples are presented to illustrate the kinematic optimization of the proposed helical gear train. The results of this study are most helpful in designing and analyzing a MHGT.

scholarly journals Tooth Surface Modification for Helical Gear Pairs considering Mesh Misalignment Tolerance

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Guosheng Han ◽  
Bing Yuan ◽  
Guan Qiao
Keyword(s):  
Surface Modification ◽  
Gear Tooth ◽  
Transmission Error ◽  
Helical Gear ◽  
Tooth Surface ◽  
Tooth Contact Analysis ◽  
Nsga Ii ◽  
Design Variables ◽  
Tooth Flank ◽  
Tooth Surface Modification

Mesh misalignment in mating the gear tooth surface is common and difficult to be determined accurately because of system deformation and bearing clearances, as well as manufacturing and assembly errors. It is not appropriate to consider the mesh misalignment as a constant value or even completely ignore it in the tooth surface modification design. Aiming to minimize the expectation and variance of static transmission error (STE) fluctuations in consideration of mesh misalignment tolerance, a multiobjective optimization model of tooth surface modification parameters is proposed through coupling the NSGA-II algorithm and an efficient loaded tooth contact analysis (LTCA) model. The modified tooth flank of helical gear pairs is defined using 6 design variables which are related to profile modification, lead modification, and bias modification. The influences of mesh misalignment on time-dependent meshing stiffness (TDMS) and STE of unmodified and modified helical gear pairs are investigated. Then, the dynamic transmission error (DTE) of modified helical gears in consideration of mesh misalignment is discussed. The results indicate that the designed modified tooth surface shows good robustness to mesh misalignment.

Sign in / Sign up

Export Citation Format

Share Document