Gear Form Research Articles

Geometric Parameter Optimization for Axial Modification in Helical Gear Form Grinding

During the axial modification in helical gear form grinding, the contact line between the grinding wheel and the gear constantly changes, and the additional radial motion can cause a “tooth surface twist” phenomenon. An optimization method for tooth surface twist error was proposed to address this. Based on the gear meshing principles, a mathematical model for axial modification in form grinding was established to solve for the instantaneous contact lines at various positions on the actual modified tooth surface. By analyzing the influence of the grinding wheel installation angle on the axial modification contact line, an optimization model was constructed to reduce the twist of the transverse profile, reduce the twist of the flank profile, reduce the helix deviation, and improve the form grinding efficiency. The practical implications of this research are significant, as the Particle Swarm Optimization (PSO) algorithm was employed to optimize the form grinding parameters, leading to a method that effectively reduced tooth surface twist error and improved the form grinding accuracy of the modified tooth surface.

Quantifying the surface damage of involute gear flanks independent of the gear datum axis

Abstract Surface damage on involute gear tooth flanks can develop during the operation of a gearbox and affects their life, durability and efficiency. Understanding the extent and severity of this damage is critical, especially in long life applications such as wind turbines where gearboxes are a critical component that incur high down time and costs for replacement. Accessing gears in service is difficult and relating gear form measurements to the gear datum is often impossible without its removal. Additionally, damage measurements are typically not areal, which can miss the most severe areas, or require lengthy measurement times. This paper describes a method for characterising and quantifying localised damage relative to the undamaged tooth surface independent of the gear datum axis, and provides a method to estimate the damage location using involute co-ordinates. By taking soft replicas of the gear flank and measuring them with optical methods, the damage is characterised. This method allows for the areal evaluation of damage that relates to involute coordinates, which can be combined with nominal data or measurements after manufacture to create data sets for simulation in tooth contact analysis models, used to train condition monitoring models or for improved maintenance programming to improve reliability and reduce costly downtime.

An Investigation into Forming of Gears Using Rotary Forging Process

An Investigation into Forming of Gears Using Rotary Forging Process

Research on the calculation method of grinding temperature field of spiral bevel gear based on generative machining

At present, the process parameter setting of spiral bevel gear grinding is mainly based on an empirical method, and the tooth surface temperature is difficult to estimate effectively during grinding, which may lead to excessive tooth surface temperature and surface burn caused by improper selection of process parameters. Aiming at the above problems, this paper presents a method for calculating the temperature field of spiral bevel gear forming based on a combination of analytical and numerical methods. The motion equation of spiral bevel gear grinding is derived based on the method of tooth surface development. The time-varying heat flow calculation method in tooth surface grinding was developed through the discrete and two-dimensional contact zone. The time-varying temperature field analysis method of spiral bevel gear forming is developed using the time-varying heat flow and finite element calculation method. The related research can realize the temperature prediction of grinding tooth surfaces and provide the basis for improving grinding technology.

Incident angle optimization with multiple conflicting objectives based on BP-MOPSO in oblique laser interferometry

The oblique incident phase-shifting interferometric measurement method is an effective technique for assessing gear tooth form deviation. In the measurement process, the tooth flank incident angle is a crucial factor determining the quality of interferograms. Addressing the challenge in traditional optical path design, where the selection of the tooth flank incident angle encounters a trade-off among quality features such as measurable tooth area (MTA), interference fringe density (IFD) and interferogram compression ratio (ICR), this paper proposes an optimized method for the tooth flank incident angle. Firstly, a comprehensive evaluation model is established to calculate and analyze the MTA, IFD and ICR of the helical gear. Secondly, by integrating BP neural network and Multi-Objective Particle Swarm Optimization (MOPSO) algorithm, a tooth flank incident angle optimization method is devised to simultaneously optimize the measurement light incident angle γ and the rotation angle of the gear axis β. Finally, simulation analyses and physical experiments are employed to demonstrate the feasibility of the proposed method, compared to before optimization, the pseudocorrelation (PSD) value has increased by an average of 34%, and the residual points have decreased by an average of 80%, confirming its capability to improve quality interferogram and measurement accuracy.

Residual stresses in gear form grinding by considering carburizing heat treatment: multi-field coupled numerical simulation and experimental verification

Residual stresses in gear form grinding by considering carburizing heat treatment: multi-field coupled numerical simulation and experimental verification

Study on the subsurface characteristics of textured surfaces under EHL condition

PurposeThe purpose of this study is to investigate the influence of surface texture on the subsurface characteristics of contact interfaces under elastohydrodynamic lubrication condition. As a typical contact form of gears and bearings, the optimization of friction characteristics at the elastohydrodynamic lubrication (EHL) interface has attracted the attention of scholars. Laser surface texturing is a feasible optimization solution, but there have been concerns about whether the surface texture of high-pair parts will affect their fatigue life.Design/methodology/approachTo examine the impact of texture preparation on the subsurface characteristics of high-pair interfaces under EHL conditions, a point contact EHL model is developed that takes into account the effect of textured surface topography. The pressure and thickness of the oil film are calculated as input parameters under different loads and entrainment velocities. The finite element method is used to simulate the impact of textures with varying diameters, densities and depths on the subsurface characteristics of the elastohydrodynamic interface. According to ISO 25178, analyze the relationship between 3D topography parameters and subsurface characteristics and study the trend of friction characteristics and subsurface characteristics based on the results of the ball on disc friction tests.FindingsThe outcomes suggest that under different rotational velocity and load conditions, the textured surfaces exhibit improved friction reduction effects; however, the creation of textures can result in significant subsurface plastic deformation and local peeling. The existence of texture makes the larger stress zone in the subsurface layer closer to the surface, leading to fatigue failure near the surface. Reasonable design parameters can help enhance the attributes of the subsurface. A smaller Sa and a Str greater than 0.5 can achieve ideal subsurface properties on the textured surface.Originality/valueThis paper investigates the influence of surface texture on the friction and subsurface characteristics of EHL interfaces and analyzes the impact of surface texture on interface contact performance while achieving lubrication improvement functional characteristics. The results provide theoretical support for the optimization design and functional regulation of surface texture in EHL interfaces.Peer reviewThe peer review history for this article is https://publons.com/publon/10.1108/ILT-10-2023-0324/

Influence of different cooling media on morphology, mechanical and corrosion of AISI 1040 grade steel

The investigation deals with AISI 1040 grade steel used in the automobile industry in the form of axles, gears, bolts, shafts, couplings, and dowels. Machined tensile samples as per ASTM E8 standard undergone heat treatment cycle i.e. heating and soaking temperature of 750 °C and followed by controlled cooling in such as furnace cooling, air cooling, quenching in water, ice, commercially available lubricant, emulsified soluble coolant. Tensile, hardness, and corrosion tests performed on samples to assess mechanical properties and corrosion behaviour. Presence of both dimples and flakes in SEM images pertaining to as received, annealed and normalized failed tensile samples demonstrates the mixed mode (ductile–brittle) and remaining failed tensile specimens dominated with the presence of flakes, which exemplifies the brittle mode of failure. The presence of martensite in hardened samples resulted in the highest strength (990 MPa), but the same has caused an adverse effect on corrosion by favouring the formation of the galvanic couple with ferrite. In contradiction to the above, annealed samples showed better corrosion resistance (-0.22v) due to the presence of larger grain size, the lesser extent of inter-granular galvanic sites, and uniform dissolution of carbides.

Numerical simulation and experimental study on hot rolling forming of spur face gears

Face gear transmission is the transmission mechanism composed of cylindrical gear and face gear. At present, the tooth making method of face gear is still tooth cutting, with low material utilization and low production efficiency. The metal streamlines are cut off, resulting in low fatigue strength of gear teeth. In this paper, the forming of hot rolling was numerically simulated, with which the characteristics of equivalent stress field, equivalent strain field, rolling force variation, and metal flow in the process of rolling were analyzed. Finally, a hot rolling experimental device was set up, by which the face gear test piece was rolled. Then its tooth surface precision was investigated. The research reveals that hot rolling spur face gears is technological feasible and has promising prospects in industrial applications.

Finite element analysis of bevel gear tooth side clearance and fatigue characteristics under alternating torque

In this paper, the effect of different tooth side clearances on the fatigue characteristics of bevel gears under alternating torque is investigated using finite element analysis technology. The article first determines the structure form and main parameters of the bevel gear and completes the establishment of the three-dimensional model of bevel gear transmission. Then, based on the principle of finite element analysis, the fatigue characteristics of the bevel gear under different tooth side clearances are simulated by ANSYS workbench software. Next, according to the simulation results, the changes in service life and safety coefficient of bevel gear with tooth side clearances are analyzed, and the relevant conclusions are drawn. Finally, combined with the finite element analysis results, the axial adjustment amount of the bevel gear assembly of this project is guided, and the actual use effect is verified. The results show that when the tooth side clearance jn is taken in the range of 0.04·m∼0.08·m, the fatigue safety coefficient and service life of bevel gear gradually decrease with the increase of tooth side clearance jn.

Gear evaluation deviations-based crucial geometric error identification of five-axis CNC gear form grinding process

The gear form grinding accuracy is significantly affected by crucial geometric errors. The gear form grinding process is a special line contact forming method. There are exclusive evaluation standards for gear grinding accuracy. While the existing sensitivity analysis for spatial point errors cannot meet the final gear report requirements. Hence, a novel method for analysis of geometric error influence on the key gear evaluation deviations (GED) is proposed. First, the actual digital tooth surface considering geometric errors and gear form grinding mechanism was constructed according to the homogeneous transformation matrix (HTM) and multi-body system theory (MBS). Second, the GED of the digital tooth surface was gained according to the modified gear meshing equations. Third, the analytic mapping relationship between the GED and machine tool geometric errors was first established. Then, the crucial geometric errors affecting the GED were identified based on a proposed Morris method. Finally, the identification results were compared to the existing publications, and the compensation discussions of crucial errors were demonstrated to validate the advantages of the proposed method. It can be found that the compensation results of GED-oriented key errors are better than those of the traditional methods, which is beneficial to the improvement of evaluation reports.

Effect of manganese phosphate conversion coating with different crystal sizes on fatigue life of 20MnCrS5 steel helical gears

Fatigue pitting is the main failure form of automatic transmission gear at present. In this paper, the contact stress of the tooth surface under different coefficients of friction is calculated by the finite element method. The contact fatigue test and transmission performance were carried out on the 20MnCrS5 helical gears after carburizing with different thicknesses of manganese phosphate conversion coating by a special gear test bench. And the influence of the solid lubricating coating on gear contact fatigue performance was deeply discussed. The results show that the contact fatigue life of the gear treated by manganese phosphate conversion coating is improved by more than 100 %, and the manganese phosphate coated gear with a thickness of 12 µm has a higher fatigue life.

Gear Defect Detection using Machine Learning

bstract: This proposed work introduces the application that is used to perceive the condition of system equipment. In machines, equipment is a very important component on every occasion it is damaged then it immediately affects on gadget's reliability. The objective of this project is to increase a system that shows the type of tools or condition of tools used to locate whether or not it's miles faulty or non-faulty manner. Convolution neural network technique might be used to locate the situation of tools and This approach is accomplished via picture processing. It takes the photograph manually from datasets or via the live digicam. The actual result of this Proposed work is to show the pick-out gear picture in which the form of gear is defective or non-defective. We explored and in comparison various CNN networks for item detection using real facts furnished by the consumer. The surface illness detection and counting the variety of equipment teeth manually isn't always correct so to clear up the trouble.

The mathematical model of non-circular crossed-axis gear

Non-circular crossed gear can be regarded as the general form of the single stage gear, which can be converted into hypoid gearing, non-circular bevel gearing, non-circular external gearing, and non-circular internal gearing with specific parameters. This paper established its mathematical model, deduced equation of its axode, and put forward a new method of tooth profile generation with introduction of relative velocity. In term of the theory above, the 3D model of a pair of conjugated gears was built, and its output angular velocity was obtained in analysis of ADAMS. Finally, the physical prototype of the gearing was developed and output angular velocity was measured as well. Both the simulation and measurement results show the motion is in good condition, which confirms the correctness of the theory and algorithm.

Experimental and Numerical Study on Stress Distribution Characteristics of Traveling Wave Resonance of High-Speed Bevel Gear in Aero-Engine

Gear failure caused by traveling wave resonance (TWR) generally occurs quite suddenly and causes catastrophic results in aero-engines. In this study, the TWR characteristics and stress distribution characteristics of a high-speed bevel gear in an aero-engine are analyzed in detail by means of experiments and simulations. Based on the acoustic waveguide system and dynamic stress test system, the TWR fatigue failure monitoring experiment of the central drive bevel gear in an aero-engine is carried out, and the TWR frequency, dangerous speed, dynamic stress and fatigue fracture characteristics of a driven bevel gear are obtained. Based on the transient dynamic analysis method and Hertz contact theory, the stress distribution characteristics of the driven bevel gear, which cannot be obtained in the test under the condition of TWR, are analyzed. The influence of the changes in the working temperature and the thickness of the spoke on the TWR characteristics and the stress distribution characteristics are discussed. The simulation and test results show that the gear has the problem of stress concentration at the root of the tooth and the back of the spoke plate under the 4th node-diameter (ND) TWR, and the stress distribution form is consistent with the fracture form of the test gear, covering 12 teeth. The relationship between the stress at the test monitoring point and the maximum stress at the tooth root is obtained, and the generality of the relationship is verified. Based on this relationship, the maximum stress of tooth root, which is difficult to monitor in the test, is predicted to be 1271.7 MPa. An accurate and convenient means to obtain the maximum stress at the tooth root of the central transmission bevel gear under TWR is obtained so as to provide a basis for failure cause analysis and central transmission bevel gear design and lay the foundation for future research focusing on the propagation of the gear under TWR conditions.

Filtering effects on involute gear form measurement

Traditional gear measurement results are used to classify a gear tolerance grade in accordance with ISO 1328-1:2013 but as more stringent requirements are placed on gear performance it is important to also characterise performance related features properly on the gear flank surface. However, the measurement uncertainty of the measurement machines is not improving at the same rate as the tolerance requirements, and it is not uncommon to have less than 10 μm tolerances to be measured with a 1–3 μm measurement uncertainty capability. This breaks the ‘rule of thumb’ that the uncertainty should be smaller than one tenth of the value you are trying to measure. It is therefore important to review the measurement and evaluation process to identify if there are any areas for improvement within our current methods. Additionally, the measurements are being used to refine gear tooth contact analysis performance models and the development of optical and high speed tactile scanning measurement methods is allowing the full 3D gear flank surface measurement a feasible option on the shop floor. Greater understanding of the involute flank beyond the standard evaluation limits is thus required. These additional requirements have prompted this review of the effect that the Gaussian filters specified in ISO 1328-1:2013 have and that their characteristics are fully understood by those who must perform and interpret the measurement results. This paper examines the effect that these filters have on measurements where micro geometry corrections, such as tip relief, or tooth tip and end face chamfers are present. Methods of minimising these effects are reviewed with specific reference to strategies defined in ISO 16610-28:2016. Recommendations are offered to minimise the effects when evaluating the gear tolerance class and quantifying gear flank micro geometry.

Erratum to: Inertia matching of CNC cycloidal gear form grinding machine servo system

Erratum to: Inertia matching of CNC cycloidal gear form grinding machine servo system

Gear Tooth‐Forming Mechanism and Experimental Research of a Spiral Bevel Gear Rolling Process Using Local Induction Heating

The gear tooth near‐net rolling process is a novel technique to enhance the tooth strength of spiral bevel gears. To study the gear tooth‐forming mechanism, high‐temperature rheological experiments of the material 20CrMnTiH were conducted using the Gleeble 1500D thermosimulation machine, and numerical simulations of the spiral bevel gear rolling forming process based on local induction heating were performed with the use of DEFORM‐3D. According to the numerical and rolling experimental results, it is feasible to produce spiral bevel gears using the rolling process with local induction heating. In order to solve the uneven material flow of the gear tooth during the tests, the material compensation coefficient k for gear forming was proposed and the shape of the gear blank was optimized. The simulation results show that the effective height of the tooth heel‐end and toe‐end in the optimized design increases by about 1 mm.

Inertia matching of CNC cycloidal gear form grinding machine servo system

Reasonable ratio between the load inertia and servo motor inertia plays a decisive role for the dynamic performance and stability of the servo system, as well as the machining accuracy of the whole CNC machine. In order to improve the control performance and contour machining accuracy of the servo system of the CNC cycloidal gear form grinding machine, an optimization design method of the inertia matching for the CNC cycloidal gear form grinding machine servo system is proposed. The two-mass servo driving closed-loop PID control system is constructed, the influence of the different inertia ratios on the dynamic performance and contour errors of the servo system are deeply analyzed, and the inertia ratio is optimized to satisfied with the servo system performance requirements. Finally, the feasibility and practicability of the optimization design method of inertia matching are verified through the inertia ratio optimization grinding experiments of the cycloid gear in the CNC gear form grinding machine. This inertia matching optimization design method provides a valuable reference for the further design of CNC machine servo system.

Investigation of the influence of material and sheet thickness on a three-stage process chain for cold forming of micro gears with a module of 0.1 mm

In many industries, there is a trend towards miniaturization of technical components, such as drive systems, which enable the solution of high-precision positioning tasks because of their low volume and high dynamics. Geared micro parts are currently mainly produced by cutting and LIGA processes, but in mass production cold forming offers ecological and economic benefits. However, the cold forming of micro gears is restricted to a lower module limit of m = 0.2 mm due to high tool stresses, size effects and handling difficulties. To solve these challenges, in this contribution a three-stage forming process chain for the manufacturing micro gears (m = 0.1 mm) is investigated. In the first stage, a pin as wheel blank is extruded from sheet metal, which is geared subsequently by lateral extrusion. Finally, the micro gear is separated from sheet by shear cutting. The aim of this study is to demonstrate the applicability of the process chain for the materials Cu-OFE and CuZn30. In addition, the influence of the sheet thickness, which has a major impact on the forming process and the material efficiency, is analyzed. The geometrical and mechanical component properties as well as the machine data are evaluated to assess the variables.