Influence of manufacturing error tolerances on contact pressure in gears

2020 ◽  
pp. 095440622097671
Author(s):  
Rikard Hjelm ◽  
Hans Hansson ◽  
Aylin Ahadi ◽  
Carin Andersson ◽  
Jens Wahlström
Keyword(s):  
Contact Pressure ◽  
Industrial Applications ◽  
Spur Gears ◽  
Pitch Error ◽  
Simulation Based ◽  
Manufacturing Errors ◽  
Gear Manufacturing ◽  
Parametric Description ◽  
Gear Geometry ◽  
Slope Error

Gear manufacturing always results in some degree of manufacturing errors, i.e. deviations from the desired gear geometry. These errors alter how the gears mesh, typically causing increased contact pressure which in turn shortens service life. It is therefore crucial to choose tolerances such that excessive contact pressure, and especially tip contact, is avoided. With increasing demands due to electrification, this becomes even more important. The aim of this paper is to study how pitch error and profile slope error affect the contact pressure in spur gears sets. The meshing is simulated using a novel simulation approach that uses a parametric description of the reference profile and gear geometry, and a hybrid model for the compliance. The method includes tooth modifications such as tip relief, and uses the true geometry to find contacts. Thus, it also handles contact outside the nominal line of action, including tip contact. The study includes cases where a gear is subjected to both pitch error and profile slope error simultaneously. Numerical examples, relevant to the automotive industry, show the outcome of the simulations. It is shown how simulation-based tolerances for relevant industrial applications can be used to improve manufacturing outcome.

Educational Model for the Kinematic Study of Non-Circular Gears

2013 ◽  
Vol 332 ◽  
pp. 297-304
Author(s):  
Liviu Ciupitu
Keyword(s):  
Numerical Methods ◽  
Industrial Applications ◽  
Point Of View ◽  
Spur Gears ◽  
Test Rig ◽  
Educational Model ◽  
Educational Test ◽  
Kinematic Study ◽  
Variation Curve ◽  
Noncircular Gears

The noncircular gears are used more and more in industrial applications. The paper presents an educational test rig for the kinematic study of non-circular gears. Two gears are studied from kinematic theoretically point of view: a gear with identically oval spur gears and another gear with identically elliptical spur gears, and simulation diagrams are presented. As for the testing rig, a gear with identically oval spur gears has been used. The researchers are able to draw with high precision the variation curve of output angle with respect to input angle. By using numerical methods for integration and differentiation other diagrams could be drawn and a comparation with simulation diagrams could be made.

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.

Transmission Error Calculation Based on Manufacturing Errors and Load

2014 ◽  
Vol 971-973 ◽  
pp. 848-851 ◽  
Author(s):  
Jian Jie Tang ◽  
Jin Yuan Tang
Keyword(s):  
Shape Change ◽  
Mathematic Model ◽  
Transmission Error ◽  
High Accuracy ◽  
Calculation Model ◽  
Gear Teeth ◽  
Error Calculation ◽  
Pitch Error ◽  
Great Consistency ◽  
Manufacturing Errors

A valid mathematic model is introduced to study the calculation of gear meshing transmission error, which is based on the manufacturing error and gear teeth deformation. Subsequently, take a pair of specific gear for example;The transmission error curves are obtained by the calculation model. The results show great consistency with the curves from Romax software, which indicates the validity and high accuracy of the mathematic model presented above. And it can be found that the shape change of transmission error curves affected mainly by the pitch error under the same conditions as the precision.

Micropitting in Wind Turbine Gearboxes: Calculation of the Safety Factor and Optimization of the Gear Geometry

2011 ◽  
Vol 86 ◽  
pp. 898-903
Author(s):  
Hanspeter Dinner
Keyword(s):  
Surface Roughness ◽  
Film Thickness ◽  
Wind Turbine ◽  
Contact Pressure ◽  
Safety Factor ◽  
Lubricant Film Thickness ◽  
Metallic Contact ◽  
Small Cracks ◽  
Gear Geometry ◽  
Specific Sliding

If the contact pressure between mating flanks of a gear set is increased, the lubricant film thickness in between is reduced to a level where the asperities of the flanks start to touch. This case where the surface roughness is of similar value as the EHD film thickness is called “mixed friction”. Due to the metallic contact of the asperities and the movement of the flanks with respect to each other, the flanks are damaged. The damaged flanks appear dull or greyish, hence the name “grey-staining” (or “Graufleckigkeit” in German), see e.g. [4] or [1]. Micropitting are small cracks on the surface of the gears (as opposed to pitting, where the cracks form below the surface), which grow into the material. The size of the damages is about 10-20 mm depth, 25-100 mm length and 10-20 mm width. Micropitting is mainly observed with case carburized gears but may also be found in nitrided, induction hardened or through hardened gears. Micropitting mainly occurs in areas of negative specific sliding. Negative specific sliding is to be found along the path of contact between point A and C on the driving gear and between point C and E on the driven gear.

Multiple Reprocessing of Gear Using Recycled Polypropylene

2014 ◽  
Vol 660 ◽  
pp. 204-208
Author(s):  
Nik Mizamzul Mehat ◽  
Amirul Aliff Jamaludin ◽  
Shahrul Kamaruddin
Keyword(s):  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Tensile Properties ◽  
Spur Gear ◽  
Spur Gears ◽  
Elongation At Break ◽  
Recycled Polypropylene ◽  
Gear Manufacturing ◽  
Multiple Processing ◽  
Satisfactory Quality

The reprocessing ability of recycled polypropylene (PP) has been investigated to evaluate the recycling feasibility in spur gear production. Up to 15 reprocessing cycles have been performed by injection moulding, and the effects on tensile properties including ultimate tensile strength, Young’s modulus and elongation at break have been studied. Results revealed that reprocessing ability of recycled PP spur gears could yield satisfactory quality as attractive as that corresponding to the virgin PP spur gear. The recycled PP gears resulted in more 10% variation in tensile properties during multiple processing. This effort might be a contribution to convince the industry to apply recycling of PP by means of multiple reprocessing in gear manufacturing.

scholarly journals Dynamical Modelling and Simulation of Spur Gears with Flank Pitch Error

2021 ◽  
Author(s):  
Lizhuang Tao ◽  
De Tian ◽  
Shize Tang ◽  
Xiaoxuan Wu ◽  
Bei Li
Keyword(s):  
Dynamic Models ◽  
Vibration Signal ◽  
Spur Gear ◽  
Transmission Model ◽  
Spur Gears ◽  
Meshing Stiffness ◽  
Pitch Error ◽  
Gear Fault ◽  
Tooth Flank ◽  
The Impact

Abstract Gearbox is commonly regarded as the most important power section of wind turbines which has been widely valued for its high malfunction rate. Gear fault researches mainly include wearing, pitting, spalling, breakage, falling off, etc, while little attention was paid to tooth Flank Pitch Error(FPE). Taking a single-stage parallel shaft spur gear as the research object, an 8-DOF gear transmission model and the FPE model were established in this paper and the gear’s time-varying meshing stiffness (TVMS) models with & without tooth FPE were obtained respectively, which the dynamic models with various tooth FPE values under different rotating speeds were simulated after. The simulation results showed that the TVMS mathematical model proposed in the paper under tooth FPE is practical at both low and high rotating speeds. Under the FPE model, side-bands are formed around each multiple of meshing frequency whose peaks are distributed by a fixed fault characteristic frequency ffp interval. The gearbox vibrates severely as the tooth FPE values and rotational speed grow. The peak value of the vibration signal is about 3 times that in case of fault-free state when the FPE value reaches 0.001rad, thus the impact of FPE on gearboxes cannot be neglected.

An Experimental Investigation on Aerospace Quality Gears Operating in Loss of Lubrication Condition

2012 ◽  
Author(s):  
Ida Bartilotta ◽  
Enrico Ciulli ◽  
Salvatore Manconi ◽  
Elena Toson
Keyword(s):  
Experimental Study ◽  
Experimental Investigation ◽  
Contact Pressure ◽  
Bulk Temperature ◽  
Spur Gears ◽  
Sliding Speed ◽  
Aerospace Applications ◽  
Lubrication Condition ◽  
Off Time ◽  
Different Levels

This paper shows the results of an experimental study carried out on spur gears for aerospace applications operating in loss of lubrication. The aim of this work was to establish a baseline for gear behavior under oil off conditions. A total amount of 40 tests were performed with gears made from 2 materials operating at different levels of sliding speed and contact pressure. In some cases the bulk temperature was measured to evaluate the heating of the running gear. A more relevant wear and heating of the gears was observed with the increase of the contact pressure rather than with the increase of the sliding speed. In all the tests the transmission was able to transfer the required power. However some tests were stopped before the required time because of the overcoming of the rig safety threshold. The results showed a different oil off time depending on the material.

Effect of Load Shape in Cyclic Load Variation on Dynamic Behavior of Spur Gear System

2012 ◽  
Vol 518 ◽  
pp. 119-126 ◽  
Author(s):  
Fakher Chaari ◽  
Walter Bartelmus ◽  
Radoslaw Zimroz ◽  
Taher Fakhfakh ◽  
Mohamed Haddar
Keyword(s):  
Cyclic Load ◽  
High Efficiency ◽  
Spur Gear ◽  
Industrial Applications ◽  
Time Varying ◽  
Spur Gears ◽  
Loading Conditions ◽  
Variable Loading ◽  
Load Shape ◽  
Variable Loading Conditions

Transmissions including spur gears are widely used in several industrial applications. They are characterized by high efficiency and capability to transmit high torques. A special attention should be made for transmissions running under varying loading conditions which have to be well monitored. The presence of this variability associated with defects that may occur in the transmission will complicate its condition monitoring. The first step to overcome this difficulty is to identify and characterize the dynamic response of the transmission in healthy conditions subjected to variable loading conditions. In this paper, a model based approach is presented in order investigate the influence of the loading shape on the vibration characteristics of the transmission. A dynamic model of a one stage spur gear transmission including a time varying loading conditions is developed. Two cases of loading conditions are considered. A parametric study is achieved and main conclusions are discussed.

THE CALCULATION OF BACKLASH IN THE GEARS BY USING THE MONTE CARLO METHOD

2020 ◽  
pp. 42-47
Author(s):  
B. P. Timofeev ◽  
N. T. Dang ◽  
M. H. Tran
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Method ◽  
Probabilistic Method ◽  
Spur Gears ◽  
The Monte Carlo Method ◽  
Manufacturing Errors ◽  
Distribution Laws ◽  
Lateral Clearance ◽  
Gear Wheels ◽  
Maximum Method

This paper is devoted to ensuring normal lateral clearance during the normalization of manufacturing errors of gear wheels and non-gear transmission elements. The task is complicated by the fact that GOST 1643–81 sets tolerances and maximum deviations relative to the working axles of the gears. The methods of calculating the lateral clearance of spur gears are considered. As the influencing factors on the lateral clearance, the thermal expansion of the link materials, the deviation of the interaxial distance of the wheels, the deviation of the engagement pitch, the radial run-out of the gear crowns, the error in the direction of the tooth, the parallelism and skew of the axles of the wheels are taken into account. The transmission accuracy parameters are read randomly. The results of calculation by the minimum-maximum method and the probabilistic method are compared. As a probabilistic calculation method, the Monte Carlo method is adopted. The input calculation parameters are taken equal to the maximum allowable values from GOST 1643–81, the parameters of the kinematic error of the wheels for calculation by the probabilistic method are considered distributed according to the equally probable and normal distribution laws.

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