Gear Tooth Modification Research Articles

Study of low-noise face gear drives associated with micro-punch webs

Face gear dynamics is addressed by many scholars. However, design solutions of low-noise face gear drives without gear tooth modifications are not to be constructed. Thus, in this study, a design solution of low-noise face gear drives associated with micro-punch webs is proposed. A calculation procession of geometric parameters of micro-punch webs is constructed, an example case of a micro-punch web for a low-noise face gear drive is calculated, which is based on the proposed calculation procession, and the noise elimination effect of the example case is predicted. Meanwhile, the impacts of geometric parameters of micro-punch webs on sound resonant frequencies are discussed. Furthermore, an experiment of the example case is conducted to check the effect of micro-punch webs on noise reductions and the proposed calculation procession and design solution. The experimental results indicate that the noise reductions of face gear drives can be accomplished by micro-punch webs under the almost same dynamic response conditions, and the fidelity of the proposed calculation procession of geometric parameters of micro-punch webs and design solution of low-noise face gear drives can be accepted. These contributions would improve engineering applications of low-noise face gear drives.

Contact between Logarithmic Crowned Teeth of Spur Gear Transmission

Gear tooth modification such as lead crowning can reduce stress concentration at the edges of the gear teeth; therefore prolong the fatigue life of gears. A logarithmical lead profile was applied on spur gears and the surface coordinate equation of logarithmic crowned tooth for manufacturing was established. On the basis of the contact mechanics model, the deformation equation of compatibility and load equilibrium equation were solved with an iterative numerical algorithm, and the corresponding programs were developed in Matlab to calculate the distributions of contact stress and von Mises stress field inside the subsurface layer at any meshing position. The numerical results of some typical examples show that the level of stress concentration before modification changes with the engaging locations of the gear teeth, and so does the amount of logarithmic modification along the line of contact, which can completely eliminate the edge effects of tooth surface at every meshing position during the spur gear transmission process, and thus improves the fatigue resistance of gear teeth surfaces.

Effects of the Gear Tooth Modification on the Nonlinear Dynamics of Gear Transmission System

The effects of tooth modification on the nonlinear dynamic behaviors are studied in this paper. Firstly, the static transmission error under load combined with misalignment error and modification are deduced. These effects can be introduced directly in the meshing stiffness and static transmission error models. Then the effect of two different type of tooth modification combined with misalignment error on the dynamic responses are investigated by using numerical simulation method. The numerical results show that the misalignment error has a significant effect on the static transmission error. The tooth crowning modification is generally preferred for absorbing the misalignment error by comparing with the tip and root relief. The tip and root relief can not resolve the vibration problem induced by misalignment error but the crowning modification can reduce the vibration significantly.

Logarithmical Crowning for Spur Gears

Gear tooth modifications, such as lead crowning, are often recommended to compensate for misalignment (e.g. assembly deviations). Lead crowning means that the tooth centre is slightly thicker than ...

Design and manufacture of plunge shaving cutter for shaving gears with tooth modifications

Gear plunge shaving is one of the most efficient ways to finish gears. It has been a challenge for a long time to design and manufacture a plunge shaving cutter to induce gear tooth modification. This paper proposes a method for designing plunge shaving cutters to manufacture gears with modifications analytically. By integrating B-spline interpolation, differential geometry, and design optimization, the goal is achieved. Efficiency is greatly improved by avoiding the traditional trial and error method.

Prediction of Mechanical Efficiency of Parallel-Axis Gear Pairs

AbstractA computational model is proposed for the prediction of friction-related mechanical efficiency losses of parallel-axis gear pairs. The model incorporates a gear load distribution model, a friction model, and a mechanical efficiency formulation to predict the instantaneous mechanical efficiency of a gear pair under typical operating, surface, and lubrication conditions. The friction model uses a new friction coefficient formula obtained by using a validated non-Newtonian thermal elastohydrodynamic lubrication (EHL) model in conjunction with a multiple linear regression analysis. The load and friction coefficient distribution predictions are used to compute instantaneous torque/power losses and the mechanical efficiency of a gear pair at any given rotational position. Efficiency measurements from gear pairs having various gear designs and surface treatments are compared to model predictions. Mechanical efficiency predictions are shown to be within 0.1% of the measured values, indicating that the proposed efficiency model is accurate. Results of a parametric study are presented at the end to highlight the influence of key basic gear geometric parameters, tooth modifications, operating conditions, surface finish, and lubricant properties on mechanical efficiency losses.

Computer Aided Loaded Tooth Contact Analysis in Cylindrical Worm Gears

A method for computer aided loaded tooth contact analysis in different types of cylindrical worm gears is proposed. The method covers both cases—that of the theoretical line and point contact. The geometry and kinematics of a worm gear pair based on the generation of worm gear teeth by a hob is presented. The full loaded tooth contact analysis of such a gear pair is performed. A computer program based on the theoretical background presented has been developed. By using this program the path of contact, the potential contact lines, the separations of mating surfaces along these contact lines, the load distribution and transmission errors for different types of modified and nonmodified worm gear pairs are calculated and graphically presented. The influence of gear tooth modifications on tooth contact is investigated and discussed.

Influence of Tooth Profile Deviations on Helical Gear Wear

In this study, a surface wear prediction model for helical gears pairs is employed to investigate the influence of tooth profile deviations in the form of intentional tooth profile modifications or manufacturing errors on gear tooth surface wear. The wear model combines a finite-element-based gear contact mechanics model that predicts contact pressures, a sliding distance computation algorithm, and Archard’s wear formulation to predict wear of the contacting tooth surfaces. Typical helical gear tooth modifications are parameterized by an involute crown, a lead crown, and an involute slope. The influence of these parameters on surface wear are studied within typical tolerance ranges achievable using hob/shave process. The results indicate that wear is related to the combined modification parameters of a gear pair rather than individual gear parameters. At the end, a design formula is proposed that relates the mismatch of contacting surface slopes to the maximum initial wear rate.

Kinematic Optimization of a Modified Helical Gear Train

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.