Contact fatigue model and life prediction of the compound motion curve-face gear pair

2020 ◽  
Vol 44 (3) ◽  
pp. 440-451
Author(s):  
Chao Lin ◽  
Peilu Li ◽  
Chunjiang He ◽  
Qingkun Xing
Keyword(s):  
Fatigue Life ◽  
Crack Growth ◽  
Contact Fatigue ◽  
Tooth Surface ◽  
Gear Pair ◽  
Face Gear ◽  
Fatigue Model ◽  
Contact Fatigue Life ◽  
Five Axis ◽  
Curve Face

Different from the common face gear pair fixed rotation motion between intersecting axes, the compound transmission of the curve-face gear is a new motion form, which can convert rotational motion into rotation and movement motion. To solve the contact fatigue life problem of this new motion form gear pair, a new contact fatigue life calculation method of the compound transmission curve-face gear pair was proposed. Based on the space gear engagement principle and the fracture mechanics theory, the theoretical contact fatigue model of the curve-face gear composite transmission was established. Considering that the contact load for every tooth is time-varying in the half-period of the curve-face gear, the contact fatigue life stage of the curve-face gear was divided into crack initiation and crack growth, and the crack growth fatigue life for each tooth was calculated using the finite element method. The curve-face gear pair was processed in the five-axis NC machining center and the compound transmission experiment platform of the curve-face gear was set up to measure the tooth surface dynamic contact stress, and the overall life of the curve-face gear was predicted. The comparison analysis between theoretical and experimental results verified the correctness of the theoretical contact fatigue calculation model.

Evaluation of Contact Fatigue Life of a Wind Turbine Gear Pair Considering Residual Stress

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Heli Liu ◽  
Huaiju Liu ◽  
Caichao Zhu ◽  
Haifeng He ◽  
Peitang Wei
Keyword(s):  
Residual Stress ◽  
Fatigue Life ◽  
Stress State ◽  
Wind Turbine ◽  
Axial Stress ◽  
Contact Fatigue ◽  
Tooth Surface ◽  
Gear Pair ◽  
Contact Fatigue Life ◽  
Gear Contact

Contact fatigue is a main fatigue mode of gears such as those used in wind turbines, due to heavy duties occurring in engineering practice. The understanding of the gear contact fatigue should be based on the interaction between the local material strength and the stress state. Under the rolling–sliding motion, the multi-axial stress state makes the gear contact fatigue problem more complicated. A numerical contact model is proposed to evaluate the contact fatigue life of an intermediate parallel gear stage of a megawatt level wind turbine gearbox. The gear meshing theory is applied to calculate the geometry kinematics parameters of the gear pair. The gear contact is assumed as a plane strain contact problem without the consideration of the influence of the helical angle. The quasi-static tooth surface load distribution is assumed along the line of action. The elastic mechanics theory is used to calculate the elastic stress field generated by surface tractions. The discrete convolute, fast Fourier transformation method is applied to estimate the subsurface stresses distributions. In order to describe the time-varying multi-axial stress states during contact, the Matake, Findley, and Dang Van multi-axial fatigue criteria are used to calculate the critical planes and equivalent stresses. Both the statistic and the deterministic fatigue life models are applied by choosing the Lundberg–Palmgren (LP), Zaretsky models, respectively. The effect of the residual stress distribution on the contact fatigue initiation lives is discussed. In addition, the crack propagation lives are estimated by using the Paris theory.

Study on the compound transmission mechanism of the curve-face gear based on screw theory

2017 ◽  
Vol 232 (17) ◽  
pp. 3115-3124 ◽  
Author(s):  
Chao Lin ◽  
Yanqun Wei ◽  
Zhiqin Cai
Keyword(s):  
Screw Theory ◽  
Transmission Mechanism ◽  
Tooth Surface ◽  
Design Parameters ◽  
Gear Pair ◽  
Face Gear ◽  
Cylindrical Gear ◽  
Cam Mechanism ◽  
Conjugate Surfaces ◽  
Curve Face

The compound transmission mechanism of curve-face gear is a new type of gear transmission based on the cam mechanism and the curve-face gear pair. It combines the transmission characteristics of the cam mechanism and noncircular bevel gear. When the compound transmission mechanism of curve-face gear is engaged in the meshing transmission, the rotating center of the cylindrical gear is fixed and used as the driving wheel, and the curve-face gear can generate the helical motion around the axis. In this paper, the meshing characteristics and motion laws of the compound transmission mechanism of the curve-face gear are studied based on the theory of screw. Based on the meshing theory of gears, the coordinate system of conjugate surfaces is established, the basic meshing theory and equation are obtained. On this basis, combined with the principle of the cam, the transmission principle is analyzed by the screw theory. The tooth surface equation of the compound transmission mechanism of curve-face gear is deduced based on the meshing theory and the related knowledge of geometry. The motion law of the curve-face gear and the change of the motion law with the change of the basic parameters of the gear pair with different design parameters are calculated and analyzed. An experimental platform is built to verify the law of motion, and the experimental results are compared with the theoretical values. The correctness of the theoretical analysis is verified, which provides a new way for the research of the compound transmission mechanism of the curve-face gear.

Research on the Discrete Algorithm of Tooth Surface for a Curve-Face Gear

2019 ◽  
Vol 142 (5) ◽  
Author(s):  
Zhiqin Cai ◽  
Chao Lin
Keyword(s):  
Gear Tooth ◽  
Theoretical Data ◽  
Surface Characteristics ◽  
Tooth Surface ◽  
Gear Pair ◽  
Face Gear ◽  
Distribution Law ◽  
Discrete Algorithm ◽  
Generating Method ◽  
Curve Face

Abstract The curve-face gear pair is a new type of face gear pair with a variable transmission ratio. Concerning the complexity of its tooth surface, based on the coordinate transformation principle and the spatial meshing theory, a discrete algorithm of this tooth surface was proposed. The determination rule of the limiting points on the tooth surface was analyzed by introducing the generating method and tooth surface characteristics of this gear tooth. Through the corresponding limiting angles and the distribution law of the contact line, the gear tooth surface was discretized, and the theoretical data points of the tooth surface were obtained. The variations in gear tooth surface in a meshing cycle and under different parameters were analyzed. By comparing the virtual tooth model and the corresponding rolling experiment, the correctness of the tooth surface discrete algorithm of the curve-face gear was verified.

Analysis of tooth contact and transmission errors of curve-face gear

2016 ◽  
Vol 231 (19) ◽  
pp. 3579-3589 ◽  
Author(s):  
Chao Lin ◽  
Chunjiang He
Keyword(s):  
Contact Line ◽  
Contact Point ◽  
Tooth Surface ◽  
Gear Pair ◽  
Face Gear ◽  
Tooth Contact ◽  
Transmission Errors ◽  
Generating Method ◽  
Mathematical Equations ◽  
Curve Face

The authors have established the mathematical equations for the tooth surface of non-circular gear and curve-face gear based on the external generating method with the same shaper cutter. The paper covers the derivation of contact line on both non-circular gear and curve-face gear, the derivation of contact point on curve-face gear, the transmission functions with errors of alignment, the analysis of transmission errors and the comparison between curve-face gear pair and normal face gear pair. The developed theory is verified by experiment.

scholarly journals The Mathematical Model of Curve-Face Gear and Time-Varying Meshing Characteristics of Compound Transmission

2021 ◽  
Vol 11 (18) ◽  
pp. 8706
Author(s):  
Yanan Hu ◽  
Chao Lin ◽  
Shuo Li ◽  
Yongquan Yu ◽  
Chunjiang He ◽  
...  
Keyword(s):  
Screw Theory ◽  
Point Contact ◽  
Transmission Ratio ◽  
Tooth Surface ◽  
Time Varying ◽  
Gear Pair ◽  
Surface Geometry ◽  
Face Gear ◽  
Meshing Characteristics ◽  
Curve Face

The curve-face gear pair is a new type of gear pair with variable transmission ratio for spatial finite helical motion. In this paper, mathematical models of a new developed curve-face gear were simplified and obtained directly by the standard shaper. The subsequent studies on the curve-face gear compound transmission characteristics were further analyzed by the combinations of the principle of space gearing and screw theory. Firstly, the conjugate tooth surface geometry as well the point contact traces of curve-face gears were derived. Secondly, the geometric relationships between gear pair and the corresponding meshing characteristics were evaluated by several basic geometric elements, including instantaneous screw, axodes, striction curve, and conjugate pitch surface. Based on that analysis, it was found that the tooth contact normal was reciprocal to the instantaneous twist, which demonstrated that the conjugate motion with the desired transmission ratio could be realized in current curve-face gear compound transmission. Moreover, the time-varying slip characteristics of the curve-face gear pair were also revealed, that is, rolling and sliding action coexist at all contact on the tooth surfaces. In brief, this work provided the theoretical basis for following researches on machining curve-face gear with standard shaper.

scholarly journals Tooth bending stress analysis of high speed curve face gear of composite transmission

2021 ◽  
Vol 22 ◽  
pp. 20
Author(s):  
Yongquan Yu ◽  
Chao Lin ◽  
Yanan Hu
Keyword(s):  
High Speed ◽  
Normal Load ◽  
Engineering Application ◽  
Tooth Surface ◽  
Gear Pair ◽  
Bending Stress ◽  
Contact Ratio ◽  
Face Gear ◽  
Cylindrical Gear ◽  
Curve Face

To promote the engineering application of composite transmission of high speed curve face gear, which consists of a cylindrical gear and a high speed curve face gear, the analysis of tooth bending stress should be taken into consideration. High speed curve face gear pair is a new type of curve face gear pair. Combined with the principle of high speed cam and curve face gear pair transmission, it can transfer the axial/rotation composite motion and power between two intersecting shafts. Based on the gear engagement principle, the gear meshing coordinate system was established and the fundamental of the high speed composite transmission was expounded. Combined with the tooth profile equation of generating gear, the tooth surface equation of high speed curve face gear was gained. Tooth force, contact ratio and normal load distribution were calculated. Then the tooth bending stress of high speed curve face gear during the transmission was calculated and analyzed in detail. Influence of basic parameters on tooth bending stress was discussed. Finally, the simulation and measurement experiment of tooth bending stress was carried out. By the comparison analysis of simulation, experiment and theory, the correctness of tooth bending stress calculation method was verified, which has important guiding significance for the further research of high speed curve face gear of composite transmission.

A numerical study on the contact fatigue life of a coated gear pair under EHL

2018 ◽  
Vol 70 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Ye Zhou ◽  
Caichao Zhu ◽  
Huaiju Liu ◽  
Chaosheng Song ◽  
Zufeng Li
Keyword(s):  
Fatigue Life ◽  
Numerical Study ◽  
Contact Fatigue ◽  
Elastohydrodynamic Lubrication ◽  
Spur Gear ◽  
Hard Coatings ◽  
Gear Pair ◽  
Content Type ◽  
Life Model ◽  
Contact Fatigue Life

Purpose Coatings are widely used in gears to keep interface from wearing excessively. The purpose of this paper is to study the effect of coating properties and working conditions on the pressure, the shear traction, stresses as well as the fatigue life of spur gear. Design/methodology/approach A numerical contact fatigue life model of a coated spur gear pair under elastohydrodynamic lubrication (EHL) is developed based on the characteristics of gear geometry and kinematics, lubrication conditions and material properties. Frequency response functions and the discrete convolute and fast Fourier transform (DC-FFT) algorithm are applied to obtain elastic deformation and stress. Mutil-axial fatigue criteria are used to evaluate the contact fatigue life based upon the predicted time-varying stress fields of coated bodies. Findings The maximum Mises stress decreases while the fatigue life increases as the coating modulus decreases. A thinner coating leads to a longer life and a smaller maximum Mises stress for hard coatings. The load has more significant effect on the contact fatigue life of soft coatings. Originality/value The developed model can be used to evaluate the contact fatigue life of coated gear under EHL and help designers analyze the effect of coating elastic modulus and thickness on the contact pressure, film thickness and stress.

scholarly journals Contact fatigue life prediction of a bevel gear under spectrum loading

2019 ◽  
Vol 15 (1) ◽  
pp. 123-132
Author(s):  
Pan Jia ◽  
Huaiju Liu ◽  
Caichao Zhu ◽  
Wei Wu ◽  
Guocheng Lu
Keyword(s):  
Fatigue Life ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Time History ◽  
Rolling Contact ◽  
Tooth Surface ◽  
Load Spectrum ◽  
Geometry Model ◽  
Fatigue Damage Accumulation ◽  
Contact Fatigue Life

AbstractRolling contact fatigue (RCF) issues, such as pitting, might occur on bevel gears because load fluctuation induces considerable subsurface stress amplitudes. Such issues can dramatically affect the service life of associated machines. An accurate geometry model of a hypoid gear utilized in the main reducer of a heavy-duty vehicle is developed in this study with the commercial gear design software MASTA. Multiaxial stress—strain states are simulated with the finite element method, and the RCF life is predicted using the Brown–Miller–Morrow fatigue criterion. The patterns of fatigue life on the tooth surface are simulated under various loading levels, and the RCF S–N curve is numerically generated. Moreover, a typical torque—time history on the driven axle is described, followed by the construction of program load spectrum with the rain flow method and the Goodman mean stress equation. The effects of various fatigue damage accumulation rules on fatigue life are compared and discussed in detail. Predicted results reveal that the Miner linear rule provides the most optimistic result among the three selected rules, and the Manson bilinear rule produces the most conservative result.

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