Search

In view of the problems of the complex design, difficult machining, and high manufacturing cost of a traditional nutation reducer, this paper intends to design a nutation reducer and study its meshing performance. First, the meshing pair is designed by the method of internal and external cutting of the shaper cutter, and the method of face gear tooth surface modification is proposed. Second, based on tooth contact analysis (TCA) and loaded tooth contact analysis (LTCA), the contact performance of the meshing pair is studied. Then, the nutation reducer is improved by using the pair instead of the internal bevel gear pair. Finally, examples are presented to test the feasibility of the improved design. The results show that the improved nutation reducer maintains the advantages of a large transmission ratio and high bearing capacity of the traditional nutation reducer and can make use of the advantages of face gears to further improve its transmission performance. This study can lay a foundation for the further application and popularization of nutation reducers. [ABSTRACT FROM AUTHOR]

Aiming at the saline soil in Binhai New Area, which is solid and sclerotic, and addressing the problem of poor quality and low efficiency of traditional rotary tillage, this research designed a high-speed rotary tiller that can realize the high-speed rotation of knife rollers to cut. The average operating speed is higher than that of the ordinary rotary tiller. We analyzed the rotary tiller operating conditions and rotary tiller knife cutting process and conducted a movement trajectory theoretical analysis to determine the rotary tiller's high-speed operating speed relationship. The working process of a high-speed rotary tiller was simulated using EDEM software. The experimental indicators included the soil-crushing rate and surface smoothness after tilling. The experimental factors included the forward speed of the machine, the rotational speed of the blade roller, and the tilling depth. An orthogonal experiment was performed to establish regression equations for the soil-crushing rate and surface smoothness. Using Design-Expert analysis software, we obtained the following optimal combination of parameters: a knife roller speed at 310 r/min, tillage depth of 13.2 cm, and machine forward speed of 4.8 km/h. At this time, the simulation values of the soil fragmentation rate and surface flatness were 90.6% and 18.2 mm, respectively. When determining the optimal knife roller speed of 310 r/min, a transient structural simulation under the mesh bevel gear transient was conducted. The simulation analysis showed that the maximum equivalent stress value was 584.57 MPa, which was smaller than the permissible stress of 695.8 MPa, meeting the bevel gear meshing strength requirements. Under the optimal combination determined by a field comparison test, the results show that the values of the high-speed rotary tiller operation after the soil-breaking rate, tillage depth, the tillage depth stability coefficient, and vegetation cover were 89.3%, 14.2 cm, 92.8%, and 90.3%. The land surface flatness was 16.4 mm, which is superior to the ordinary rotary tiller operation effects, meeting the agronomic requirements for pre-sowing land preparation for peanuts in the saline land of Binhai New Area. [ABSTRACT FROM AUTHOR]

Aiming at the problems of surface wear and fatigue failure of spiral bevel gears of heavy-duty axles, a new surface strengthening technology of induction heating composite shot peening (IHCSP) is proposed. This article designs an IHCSP test scheme to achieve surface composite strengthening of spiral bevel gears. The wear performance and fatigue strength of the gears were analyzed by using the gear fatigue transmission test bench, and the residual stress, microhardness, surface topography, and microstructure of the gears' surface were measured. The results show that IHCSP increases the maximum compressive residual stress of the gear surface to − 1082.79 MPa, the corresponding layer depth is 87 um, the gear surface microhardness is 782.7 HV, and the hardened layer depth is increased by 43%. Meanwhile, the wear resistance of spiral bevel gears is improved, the gear surface wear error is reduced by 30.5%, and the fatigue life is increased by 31.4%, which proves the effectiveness of IHCSP in improving the fatigue strength of spiral bevel gears. [ABSTRACT FROM AUTHOR]

Spiral bevel gears are widely used in automobile transmission systems, and their performance plays a crucial role in driveline safety and transmission efficiency. However, studies on the lubrication performance and churning power loss of spiral bevel gears under an injection lubrication system are still insufficient. In this study, a numerical simulation model consisting of a nozzle, a spiral bevel gear pair, and a box was developed. The effects of different injection velocities, nozzle diameters, oil temperatures, and injection angles on the lubrication performance were simulated and analyzed. In addition, a churning loss prediction model was established by constructing an orthogonal scheme, dimensional analysis, and multiple linear regression, and a spiral bevel gear churning loss test rig was built to verify the accuracy of the prediction model. The results show that the injection velocity and nozzle diameter have a more pronounced effect on the oil volume fraction on the gear surface, while the lubricant temperature has little effect on it; the relative error between the predicted and experimental values of the established model is within 10%, which meets the industrial requirements. This work helps scholars to understand the lubrication mechanism of spiral bevel gears and provides a method to predict the churning power loss of spiral bevel gears under oil injection systems. [ABSTRACT FROM AUTHOR]

All time-scale decomposition (ATD) is a non-parametric adaptive signal decomposition method, which relies on zero-crossing points and extreme points to jointly construct the baseline, achieving the suppression of modal mixing caused by the proximity of component frequencies. However, ATD is unable to solve mode mixing induced by noise. To improve this defect, a new noise-assisted signal decomposition method named ensemble all time-scale decomposition (EATD) is proposed in this paper. EATD introduces the noise-assisted technique of complementary ensemble empirical mode decomposition based on ATD, adding complementary noises to mask the noise interference in the signal. EATD not only overcomes mode mixing caused by noise but also preserves the capability of ATD to suppress mode mixing caused by the proximity of component frequencies. Simulation signals and bevel gear fault signals are utilized to validate EATD, and the results indicate that EATD can successfully overcome mode mixing induced by noise and can be effectively applied for gear fault diagnosis. [ABSTRACT FROM AUTHOR]

ABSTRACT A thermal elastohydrodynamic lubrication model is combined with a wear model under mixed lubrication to investigate the lubrication performance and wear characteristics of double‐circular‐arc spiral bevel gears for nutation drive. Moreover, the effects of operating conditions on the characteristic parameters of the film are analysed under the mixed lubrication point‐contact conditions. Furthermore, the characteristics of gears in terms of friction coefficient and wear depth are discussed. According to the results, the performance of lubrication and wear during the mutual meshing of the convex tooth surface of the external bevel gear and the concave tooth surface of the inner bevel gear is better than that during the mutual meshing of the other pair of tooth surfaces. The minimum film thickness of the whole meshing process occurs near the inner of the bevel gear due to the joint action of the load and the end edge effect. Moreover, an increase in torque at a certain rotational speed is favourable to the lubrication performance of the meshing process. The wear depth in the double‐circular‐arc spiral bevel gears' meshing process is heavily influenced by the roughness of the tooth surface. [ABSTRACT FROM AUTHOR]

To obtain ideal fatigue resistance, low‐carbon steel spiral bevel gears for axles generally undergo continuous carburizing‐quenching‐tempering heat treatment (hereinafter referred to as hard‐tooth surface heat treatment). Herein, on the basis of multifield coupling effects, a multifield coupling model of hard‐tooth surface heat treatment is established. The model considers the latent heat generated via phase transformation and the influence of surface carbon concentration on the temperature at which martensitic transformation commences (Ms). A numerical simulation and experimental verification are conducted on the hard‐tooth surface heat treatment process for the 20CrMnTi steel spiral bevel gear. Results show that the maximum relative errors in carbon concentration, hardness, retained austenite content, and residual stress between the predicted and measured values are 4.8, 4.3, 4.6, and 7.6%, respectively. In addition, the article investigates the microstructure and stress evolution patterns of the spiral bevel gear during quenching. The results reveal that Ms decreases with increasing carbon concentration on the gear surface, resulting in the martensite transformation on the surface lagging significantly behind that at the core. The proposed model provides a reference for developing a formulating strategy for a realistic hard‐tooth surface heat treatment process of spiral bevel gear. [ABSTRACT FROM AUTHOR]

Gear modification, which involves the removal of material from the theoretical surface to improve the contact characteristics of the gear face, is widely applied in gear vibration reduction and noise optimization design. This paper establishes a dynamic model of the straight bevel gear (SBG) transmission system to accurately and efficiently evaluate the effects of different modification strategies on the vibrational characteristics of SBGs. Initially, the time-varying meshing stiffness (TVMS) of standard SBGs was calculated, and methods such as the slicing method and deformation coordination equations were used to calculate the TVMS under tooth profile modification (TPM), Lead crown relief (LCR), and comprehensive modification (CM), which were then validated against finite element method (FEM) calculations. Subsequently, taking into account the impact of time-varying meshing point vectors and the degree of contact overlap, a finite element node dynamic model of the SBG transmission system was established. Finally, by comparing the dynamic characteristics under different modification conditions, the study further elucidates that selecting the appropriate modification method and amount according to different service scenarios is an effective means to suppress gear transmission vibration. This research provides a theoretical basis for the design of gear modification and vibration control for SBGs. [ABSTRACT FROM AUTHOR]

Purpose and Methods: The paper presents the electromechanical modelling of straight bevel gear pair with multiple fault conditions such as healthy tooth, chipped tooth, and missing tooth. The time-varying mesh stiffness (TVMS) of straight bevel gear pair is developed analytically using Tredgold approximation. The developed model is simulated by incorporating TVMS value at different fault conditions one by one to study the system's dynamic characteristics. Results: In this study, the severity of multiple faults are effectively shown by vibration responses in time and frequency domain. The simulated results are compared and verified with experimental results under multiple fault conditions. Conclusion: The comparative results show that the developed model successfully give similar trend like experiment. The paper may provide some important understanding about the dynamic behaviour characteristics of straight bevel gear system under different fault conditions. [ABSTRACT FROM AUTHOR]

This paper presents an innovative digital tooth surface precision control model(DTS-PCM) for spiral bevel gears, focusing on the contact parameters derived from the surface synthesis method(SSM) and the pinion tooth surface contact control parameters under Gleason expert manufacturing system(GEMS). This model enables the direct derivation of tooth cutting adjustment parameters for Gleason machine tools, facilitating a seamless integration of design theory with practical processing. Firstly, a novel method for accurately determining the curvature parameters of pinion tooth surfaces, based on predefined contact parameters, has been developed using ease-off topology. Then, based on the pinion gear cutting pitch cone model, a coupled tooth line vector transformation model is proposed to calculate the principal curvature parameters of the nodes. Additionally, a set of equations for the pinion tooth surface contact control parameters is derived, and a formula for calculating the pinion gear cutting adjustment parameters is provided. Finally, two sets of pinion tooth surface contact control parameters were obtained using DTS-PCM: the calculated tooth contact analysis(TCA) and ease-of-topology results. The findings demonstrate that the proposed method is largely consistent with the outcomes of the GEMS calculations, thereby validating the accuracy of DTS-PCM. This indicates that the method can be directly integrated with GEMS software, facilitating practical applications that shorten the design and processing cycle. [ABSTRACT FROM AUTHOR]

Introduction and Background: Spiral bevel gears are ubiquitous in numerous power transmission systems. The exigent demands such as high performance, more strength and less noise in helicopter drives can be met by selecting the optimal geometrical design parameters. However, a comprehensive study on the influences of geometric parameters on the transmission system dynamics is not found in the literature. Objective: Therefore, in this study, the effects of geometric design parameters such as spiral angle, pressure angle and pitch cone angle on the spiral bevel gear set dynamic characteristics for various boundary conditions are studied. Method: Firstly, the analytical modelling of coupled lateral-axial–torsional vibrations of the spiral bevel gear set is derived theoretically under few assumptions. Then the emphasis on the effects of geometric parameters on the dynamic characteristics such as critical speeds, coupled mode shapes and unbalance vibration response of the gear pair supported by flexible and rigid boundary conditions are investigated numerically. Results: Under rigid support conditions, it is observed that there is no remarkable influence of geometric parameters on the critical speeds. However, the unbalance response amplitudes at and around the resonance peaks are notably affected. Whereas the critical speeds and unbalance responses are essentially affected by the variation of axial and torsional stiffness at the supports. Meanwhile, the influence of geometric parameters on the critical speeds corresponding to torsional and axial modes is remarkable for the flexible support conditions. Furthermore, the steady-state response due to combined torsional and unbalance excitations is also studied, and the results show that the geometric parameters influence the axial, lateral and torsional responses. Conclusion: The results obtained through this study are useful in the design of the spiral bevel gear set. [ABSTRACT FROM AUTHOR]

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the gear transmission process, the tooth surface friction environment is very complex, and the gear surface is prone to high stress, strain and wear, which can easily cause gear failure. In order to alleviate the wear of the gear tooth surface and improve the anti-glueing ability of the tooth surface during gear transmission, this paper solves this problem by introducing micro-texture in the meshing gear. Firstly, three kinds of micro-textured gears are designed based on the mechanism of micro-textured structure in the friction vice and the meshing position during gear transmission. Secondly, finite element simulation tests were conducted with and without micro-textured gears, and the stresses, strains, and wear levels experienced by the micro-textured gears during transmission were analyzed. The study found that torque and rotational speed have a direct impact on the gear surface. Compared to traditional gears, gears with micro-textures distributed above the pitch circle promoted a 51.57 % reduction in stress and a 61.81 % reduction in strain, also altering the concentration locations of stress and strain on the tooth surfaces, which led to a 50.51 % reduction in wear. This research has significant implications for improving the frictional performance of gears, with micro-textures on the tooth surfaces acting as containers for lubricants and metal filings, preventing abrasive wear of the friction pairs on the tooth faces and enhancing the durability of the gears. [ABSTRACT FROM AUTHOR]

Aiming at the problems of low machining efficiency and insufficient fatigue strength of spiral bevel gear, a numerical simulation and parameter optimization method for warm rolling forming of spiral bevel gear pinion was proposed. Based on deform-3D finite element simulation software, the influence laws of technological parameters such as friction factor, feed speed and initial rolling temperature on the forming stress and strain of the pinion during warm rolling were analyzed. Combined with orthogonal test, the optimization of process parameters was completed, and the warm rolling forming test of the pinion was carried out by using the best combination of process parameters. The tooth surface and pitch are tested. The results show that the total deviation of convex surface and concave surface are 14.4 µm and 14.1 µm. The cumulative total deviation of gear pitch is 57.0 µm and 56.3 µm and the accuracy level has reached to GB 8. The accuracy of tooth surface and pitch of gear meets the requirements of gear grinding after heat treatment. [ABSTRACT FROM AUTHOR]

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Spiral bevel gears are extensively employed in mechanical transmissions; however, they are prone to adhesive wear when operating under high-speed and heavy-load conditions. Research indicates that the tooth surface roughness of gears significantly influences the friction and wear of the meshing gears. The present study delves into the origins of tooth surface roughness through the integration of the W-M function and fractal theory. Utilizing an involute helical gear with surface roughness for tooth cutting, a three-dimensional model is established with roughened tooth surfaces. This paper introduces an approach to developing three-dimensional gear models with roughness and applies the finite element method to perform thermodynamic analysis on gears exhibiting diverse levels of surface roughness. The thermal analysis of gears with varying degrees of roughness was conducted using the finite element method. Comparative analysis of the results under specific operating conditions elucidated the impact of roughness on tooth surface temperature rise. In order to validate the simulation model, an experimental test platform for spiral bevel gears of identical size was established. This model integrates tooth surface roughness with thermodynamic analysis, allowing for the rapid assessment of tooth surface temperature rise under different machining conditions, and reducing the cost of validating predicted tooth surface load-carrying capacity. [ABSTRACT FROM AUTHOR]

Rotary forging is an incremental bulk forming process, possessing salient advantages compared with the conventional forging, including reduced force, smoothness of operation, lower investment, apt for near net shaping and producing workpieces with intricate profiles. However, the conventional rotary forging machines suffer serious limitation in their kinematics, which originates from their simple eccentric mechanism of the actuating device. The parallel-kinematics hexapod mechanism with six degrees of freedom can circumvent this limitation. The theory and practice of this concept has been successfully implemented in the present study. The inverse kinematics of hexapod has been adapted to the kinematics of the rotary forging processes. This could yield a proper method to generate the orbitally rocking motion prevailing in the process. In order to investigate the material flow in the lower die, physical modeling was carried out by the use of plasticine and several experiments were conducted in a hexapod machine. The final shapes of the workpieces, the degrees of die filling, and the forging forces were compared with the conventional forging, indicating improved results. It was observed that the motion pattern in the rotary forging influences the time and the force required for forming. The maximum forces required for rotary forging using the circular and planetary motion patterns were 32 N and 38 N respectively. In comparison, conventional forging required a significantly higher force, approximately 200 N. The time required to form a bevel gear using planetary motion was almost half of the time needed for circular motion. [ABSTRACT FROM AUTHOR]

This study presented a novel analytical method to investigate the coupled dynamic behavior of a supercritical helicopter tail transmission system, taking into account the friction-induced self-excitation of the floating spline, the rubbing between the limiting ring device and the shaft, and the time-varying meshing excitation experienced by multiple spiral bevel gear pairs. The tail transmission shaft was first modeled using Timoshenko beam elements in local coordinates. Subsequently, the centralized parameter method was employed to build dynamic models of critical components such as the floating spline, limiting ring devices, and multiple spiral bevel gear pairs. Finally, the system's dynamic equations were derived utilizing the interface coordination principle and spatial coordinate transformation. Numerical analyses were conducted to examine the dynamic behavior of the system, including the coupled vibration properties and the impact laws of the limiting ring device and floating spline on the system's response. The findings indicated that the limiting ring device resulted in a cross-critical vibration reduction in the tail horizontal shaft, achieved through the mechanisms of dry friction and rubbing impact. However, as a consequence, the natural and rubbing frequencies of the other shafts were generated. The self-excited vibration of the system, brought about by the friction of the spline tooth surface, had a significant impact on the shaft that was directly connected. The emergence of the self-excited vibration occurred when the speed surpassed the first-order natural speed of the directly connected shaft, with the corresponding self-excited frequency being the first-order natural frequency of said shaft. With the increase in the tooth surface friction coefficient of the spline, it even caused continuous rubbing between the shaft and the limiting ring device under a supercritical condition. The proposed dynamic analysis approach holds promise in offering theoretical guidance for the reduction of vibration and noise generated in supercritical tail transmission systems. [ABSTRACT FROM AUTHOR]

The line gear (LG) exhibits promising applications in micromachinery owing to its simple structure and minimal teeth count. This paper aims to advance the meshing theory of LG and introduce a conical LG tooth configuration specifically tailored for micro-machining that is capable of driving with high performance. Based on the meshing principle of LG, a conical line gear pair with vertical flank (VFLG) of the driving gear was designed. Subsequently, adhering to the curvature non-interference principle that no local interference occurs in the meshing process and the specified range of fitting error in one direction, the design parameters for LG were determined. A comparison of the contact stress between two sets of different contact line types revealed the distinct advantage of VFLG with parameters identical to those of traditional LG. The experimental results conclusively demonstrate a transmission ratio error of 0.004, affirming the feasibility of the design. The curvature noninterference design formula proposed in this paper refines the LG design theory, and the novel LG design method presented holds significant implications for subsequent micromachining. [ABSTRACT FROM AUTHOR]

In this paper, an innovative hamburger-shaped eddy current damper (HSECD) is presented to mitigate the responses of civil structures subjected to wind excitations. The damper's capacity to dissipate energy is significantly enhanced through a two-phase configuration of permanent magnets (PMs) and two transmission devices: a ball-screw assembly and a bevel gear group. The improved eddy current damper (ECD) solves the problem that the low damping density of traditional ECDs hinders their application to the field of vibration control for civil structures. First, the construction details of this novel HSECD are elaborated, and its principle is discussed through theoretical analysis and numerical simulation. Subsequently, a prototype of the HSECD was fabricated, and cyclic tensile–compressive tests were conducted to investigate its mechanical performance. Furthermore, the temperature effect on the damper's maximum output force was analyzed, and more than 10% performance degradation was detected in tests with a continuous loading of 1,250 s, while the damper performance quickly reached a steady state after a certain decline. A theoretical model of the HSECD was then established to simulate its hysteretic characteristics, and the accuracy was verified by comparing it with the test data, where their energy error was only 1.9%. Finally, the application of the HSECD to both a single-degree-of-freedom (SDOF) simplified system and a jacking engineering system demonstrates its excellent control performance because the reduction ratios of their peak displacement were as high as 31.1% and 40.9%, respectively. These results highlight the significant practical value of the HSECD in mitigating the wind-induced vibrations for engineering structures. [ABSTRACT FROM AUTHOR]

Copyright of Automobile Technology & Material is the property of Automobile Technology & Material Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper presents comparable sets of the no-load power loss as a product of windage and churning behaviors of a family of various rotating parts (i.e., disc, spur gear, straight bevel gear, and orthogonal face gear). Experimental measurements were carried out under pure air only and under partial immersion in oil to qualify and quantify the windage and churning effects of no-load power losses of a family of spur, bevel, and face gears along with a representative disc as the baseline. Aiming at exploring the influence of gear teeth on the total no-load power losses, two different theoretical analytical approaches are introduced to account for the churning contributions, by which the total power losses are estimated. Both analytical approaches compare well with the experimental findings. Furthermore, a spatial intersecting cross-axis gear (e.g., straight bevel gear and orthogonal face gear) results in higher no-load power losses than that of a representative disc or a parallel-axes gear. The significance of gear teeth (gear vs. disc) on windage behavior is presented, as well as the gear windage effects on the churning phenomenon in a high-speed splash-lubricated gear. [ABSTRACT FROM AUTHOR]

To passively achieve an inertial device with unidirectional force transmission similar to Bang Bang control, this study introduces a novel energy dissipation device known as the resettable‐inertia damper (RID). The ingenious motion principles of the RID, encompassing a rack‐and‐pinion, bevel gear commutation system, speed transmission, and eddy current damping, are elucidated in detail. In particular, a unidirectional rotational flywheel within the device selectively engages when the primary structure reciprocates. The physical mass of the flywheel undergoes conversion into an amplified inertia through the rack‐and‐pinion mechanism, which enables the enhancement of damping effects coupling the flywheel rotation and eddy current configuration. A coupled multibody dynamic model, combining the clutching effect, the flywheel inertia, and the rotational damping, is formulated to analyze the system with RID (RIDS). Currently, an analysis of the hysteretic behaviors of RID is carried out. To facilitate the design and evaluation of the performance of RIDS, an equivalent linearization method is proposed for RIDS. The feasibility of this simplified method is validated under harmonic excitation. Additionally, the study examines the performance of equivalent linear systems (ELSs) and RIDS under natural ground motions and stochastic stationary excitation in peak and variance responses levels, respectively. Comparison of RID with traditional inerter shows that RID can achieve a more pronounced control with less force transferred to the structure and with the potential to recover vibration energy, highlighting its unique advantages. [ABSTRACT FROM AUTHOR]

The efficiency of bevel and hypoid gears is, alongside load capacity, one of their most important design criteria. To consider the efficiency of bevel and hypoid gears during the development and design process, validated calculation methods based on experimental investigations are necessary. However, the isolated experimental investigation of the load-dependent power losses of bevel and hypoid gears has not been adequately investigated, as most of the experimental investigations consider the complete gearbox. This paper presents a test rig that allows for the experimental investigation of the efficiency of bevel and hypoid gears with a measurement uncertainty of the efficiency of ∆ η ≤ ± 0.08 % according to the Guide to the Expression of Uncertainty in Measurement (GUM). Using the developed test rig, experimental investigations on the efficiency behavior of bevel and hypoid gears regarding the influence of the axial offset, driving direction, and microgeometry are carried out for different operating points varying in circumferential speed and load. This paper discusses the methodology and the first experimental results of a study on the efficiency of bevel and hypoid gears in detail. [ABSTRACT FROM AUTHOR]

This paper presents an innovative and comprehensive methodology for loaded tooth contact analysis (LTCA) of spiral bevel gears, integrating ease-off surface computation with high-precision virtual generating tooth surfaces. The methodology integrates an error-sensitivity analysis model with a semi-analytical LTCA model for spiral bevel gears based on ease-off surfaces, developed using a Universal Generation Model. By leveraging sophisticated corrections in the machining process, the desired ease-off surfaces are obtained, ensuring the accuracy of the generated tooth surfaces. This simulation ensures minimal errors between theoretical and virtual generating tooth surfaces, providing a reliable basis for LTCA. The LTCA model is formulated using CNC-generated tooth surfaces, focusing on misalignments such as pinion offset, adjustment errors, and angular position errors along the pinion and gear axis. The feasibility and effectiveness of the proposed method are verified through comparisons with LTCA software analysis results, demonstrating its high accuracy in predicting the impact of misalignments on contact patterns and load distribution. This integrated approach offers significant advancements in the design and analysis of spiral bevel gears, providing a robust tool for predicting and analyzing gear performance under various misalignment conditions. The combined methodology enhances the reliability and accuracy of LTCA, ensuring optimal performance and durability of spiral bevel gears in practical applications. [ABSTRACT FROM AUTHOR]

Under the working conditions of heavy load and alternating load, spiral bevel gears are prone to tooth root cracks, which lead to tooth fractures. It is necessary to clarify the influence mechanism of cracks on meshing characteristics and provide theoretical basis for fault diagnosis. The finite element model of bevel gear pairs is constructed, and the static contact simulation analysis is carried out by ANSYS software. The fault models of various crack types are set up by the method of unit node replacement, and the influence of cracks on the meshing characteristics of spiral bevel gear pairs is discussed. The results show that when the contact ellipse of gear teeth moves to the crack area of gear teeth, the meshing stiffness gradually decreases with the increase of the severity of the crack, and the maximum reduction of stiffness under the condition of plane crack, space crack and broken teeth is 27. 58%, 14. 12% and 32. 82% respectively. The contact ellipse position, crack position and depth of gear meshing will make the contact stress of tooth surface and the bending stress of tooth root have different increasing and decreasing trends. [ABSTRACT FROM AUTHOR]

Hot rolling forming enhances the overall mechanical performance of spiral bevel gears. However, it introduces challenges including high-forming temperatures (above 850°C), extensive deformation and oxidation of tooth surfaces, which limit the gear quality. This paper proposes a novel method of warm rolling finishing forming process of spiral bevel gears, which aims at improving the precision of tooth flanks forming. An elastoplastic finite element model with predefined deviations of tooth flanks is developed. The impacts of various process parameters on the deviations of tooth flanks are analyzed, and the optimal conditions for the warm rolling finishing process are determined. Experiments of hot and warm rolling forming are conducted, and the deviations of the tooth flanks are measured after each process. The obtained results demonstrate that the maximum deviations of the concave and convex sides of the tooth flanks following warm rolling decrease by 84% and 81%, respectively. In addition, the warm rolling improves the roughness of the tooth flanks and significantly reduces their deviations. The effectiveness and feasibility of the proposed method are then verified. The results obtained in this study provide a scientific basis for the precise manufacturing of spiral bevel gears. [ABSTRACT FROM AUTHOR]

Geometrical tolerances are used to limit the variations of the actual measured features of a part relative to its ideal features or datum features in form, profile, orientation, location, and run-out. Although the geometrical feature variations can also contribute significantly to the manufacturing cost as well as the quality of a product, the current studies on concurrent tolerancing mainly focus on the concurrent optimal allocation of dimensional tolerances, with little consideration of geometrical tolerances. The purpose of this paper is to extend the concurrent tolerance allocation model to take the geometrical tolerance requirements into account for multi-process machining parts. Firstly, the function relationship between the quality loss and the process tolerances of a product with multiple relevant assembly dimensions is studied, and the geometrical tolerance is attached to the contact point of the corresponding feature surface of the part as a zero-length dimension parameter with tolerance. Then, the functional assembly tolerances are assigned to process dimensional and geometrical tolerances based on the given part process planning, during which geometrical tolerances are treated as the equivalent dimensional tolerances or the additional tolerance constraints according to their own characteristics. An extended model for concurrently allocating dimensional and geometrical tolerances is established by using total cost minimization as the criteria, the product function constraints, geometrical tolerance constraints, and economical process tolerance bounds as constraint conditions, and the nonlinear programming technique is used to solve the extended model to obtain the optimized design tolerances and process tolerances. Finally, an example of concurrent tolerance allocation of bevel gear assembly is given to validate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

A vectorized analytical model for the cutting dynamics in the spiral bevel gear face hobbing process has been developed, which is based on machine tool kinematics and vibration vectorization. The structural modal parameters of the cutter head spindle system are obtained through experimental modal analysis with hammer impact testing. The analytical model is utilized to simulate the generation of simulated vibration acceleration signals during spiral bevel gear hobbing. A wavelet threshold denoising method is applied to process the simulated vibration signals of the spiral bevel gear face hobbing with added white noise. Signal processing methods, including short-time Fourier transform are employed for time-domain analysis, frequency-domain analysis, and time–frequency-domain analysis of measured signals and simulated signals, thereby extracting the corresponding statistical features. In addition to the results of the experimental modal analysis, the causes of chatter in spiral bevel gear hobbing are discussed in detail, revealing that the main factor is cutter head vibration in the Y direction of the Hunan ZDCY CNC EQUIPMENT YKA2260 machine tool used in this research. The error in the time-domain characteristic parameters between simulated signals and measured vibration acceleration signals is within 15%, with a difference of 3.5% in spectral peak values. The predicted tooth surface morphology from simulation matches the actual morphology on the workpiece, comprehensively validating the reliability of the cutting dynamics model for the spiral bevel gear face hobbing process. Another conclusion drawn from numerical simulation experiments is that the amount of tooth surface waviness of the spiral bevel gears is the ratio of tool chatter frequency to cutting fundamental frequency. [ABSTRACT FROM AUTHOR]

Given the deformation issues in machining segmented equal-base bevel gears, this paper investigates the variations of additional stress during the machining process, considering the gear blank material, residual internal stress, and gear blank design. A model for calculating internal additional stress and torque during gear machining has been developed. The calculation formula for the bending deformation of the gear blank has been derived using the torque–area method. By analyzing the time-varying stiffness of the blank, a calculation model for the bending deformation of the gear blank has been constructed, and the projection analysis of gear stock deformation has been completed. Based on the cumulative superposition effect of its deformation projection, a calculation model for the overall deformation of the segmented gear blank has been formulated. The deformation calculation model has been validated through finite element simulation, deformation calculation, actual machining, and measurement verification. [ABSTRACT FROM AUTHOR]

The results of research and testing of the technology of strengthening contact surfaces in an oil medium with the addition of fluorinated graphite of the teeth of bevel gears and rolling bearings are presented. The technology provides a significant increase in resource by slowing down the development of fatigue damage to the teeth of bevel gears and rolling bearings of the NK-14ST engine starter drive. [ABSTRACT FROM AUTHOR]

High-precision straight bevel gears are commonly manufactured using the generating method, which requires specialized equipment such as a dedicated or five-axis CNC machine for mass production. While the existing forming process can also be applied to produce SBGs, which offers a more cost-effective solution with a four-axis CNC machine, it results in inferior gear contact performance. This paper introduces a novel forming (non-generating) method. The goal is to enhance the gear contact performance. First, the tool profile of the pinion is computed based on the ring gear's conjugate tooth surface. Subsequently, a sensitivity analysis on the tooth surface, considering four-axis motion coefficients, facilitates the calculation of correction amounts for tooth cutting motion. This process determines the pinion's tooth surface, optimizing the contact performance by ensuring it contacts the ring gears precisely at a point. Ease-off and tooth contact analyses are utilized to evaluate the contact performance of the designed gear pair. Furthermore, VERICUT software is employed for cutting simulation to validate the NC machining codes. After this, a cutting experiment is conducted to verify the correctness of our mathematical model. [ABSTRACT FROM AUTHOR]

In order to predict the spiral bevel gear churning power loss, based on the Computational Fluid Dynamics (CFD) method, the computational model for the splash lubrication of the spiral bevel gear pair is established and validated by experiments. The churning power loss of spiral bevel gears is obtained and the corresponding flow field distribution in the gearbox with a pair of spiral bevel gears is analysed under a standard operating condition. For the churning power loss of spiral bevel gears, the loss of teeth surface is mainly caused by pressure while the loss of gear side is mainly generated by the viscous force. The effects of the gear rotational speed, oil level, oil temperature and oil shroud on the churning loss are also investigated and analysed. Ultimately, an optimisation method is proposed for the original spiral bevel geared transmission. [ABSTRACT FROM AUTHOR]

Accurately and fast calculation of single tooth load contact state of a gear pair is the basis for accurate calculation of multi-tooth load contact analysis. Therefore, this study proposed a semi-analytical quick single tooth load tooth contact analysis (Q-SLTCA) method. First, the ease-off tooth contact analysis (ease-off TCA) method was established, and a numerically stable initial contact stress distribution and contact ellipse analytical model was derived. Then, considering the influence of edge contact, the real-time division method of gear tooth slice was derived. Based on this, the equivalent principle of contact elliptical node and the load correction strategy were innovatively proposed. Then, the calculation method of the meshing characteristics of the tooth slice was established by coupling the boundary element method (BEM) with the equivalent cylindrical Hertz contact theory. The bending deformation, tooth root stress distribution, contact stress, contact deformation and meshing stiffness of the tooth slice were analyzed and calculated, and the instantaneous meshing stiffness of the single tooth was determined by combining the parallel method of the gear tooth stiffness. Finally, a single-tooth finite element method (FEM) meshing model was created for comparison with the method in this study, which verified the calculation accuracy and efficiency of the proposed method. This method can be easily developed into a quick multi-tooth load contact analysis algorithm, which can provide a new method for gear tooth crack and failure analysis. • Propose a real-time division method of tooth slice combined with ease-off TCA. • Propose an elliptical node equivalent principle and load correction strategy considering edge contact. • Derive the BEM equation for calculating the mechanical properties of the tooth slice. • Use BEM and Hertz theory to conduct load tooth surface contact analysis. [ABSTRACT FROM AUTHOR]

Load-capacity has always been one of the performances that is paid much attention to in the development of bevel gear transmission applications. Consequently, the mathematical model of novel bevel gear with high load-capacity based on geometric elements is proposed in this paper, which could be applied to the aviation, aerospace and other fields. In parallel, the design principle and design method of the novel bevel gear are introduced in detail. Subsequently, the conditions for tooth surface continuity and non-interference are derived. Furthermore, the model of novel bevel gear is established. Finally, the load-bearing characteristics are analyzed, revealing that an increase in the number of contact points could significantly enhance the load capacity of the bevel gear pairs. When the load torque applied to bevel gear II is 100 Nm, the contact pressure endured by the bevel gear pair with five-point contact is decreased by 41.37% compared to the bevel gear pair with single-point contact. When the number of contact points is the same, increasing the distance between the contact points could also reduce the contact stress. This provides strong theoretical support for the application of the bevel gear based on the geometric elements. [ABSTRACT FROM AUTHOR]

Due to machining errors, location inaccuracies, human error, and various other factors, it is challenging to avoid assembly errors during the production of spiral bevel gears (SBGs). When SBG assembly errors occur, it can cause the appearance of edge contact and may even lead to severe tooth tip chipping. In this study, we propose an improved method based on loaded tooth contact analysis (LTCA) to examine mesh characteristics, including time-varying mesh stiffness (TVMS), unloaded transmission error, and contact stress. Furthermore, we explore the effects of assembly errors and tooth tip chipping. Moreover, it is observed that assembly errors can alter the contact area of SBGs and potentially reduce the peak-to-peak value of TVMS. Additionally, the occurrence of tooth tip chipping decreases TVMS within the chipping region, lowers transmission error, and increases maximum contact stress. Notably, when assembly errors are present, the reduction in TVMS due to tooth tip chipping exceeds that of a properly assembled SBG pair. [ABSTRACT FROM AUTHOR]

Loaded meshing transmission performance optimization has been an increasingly significant target for the design and manufacturing of aerospace spiral bevel gears with low noise and high strength. An innovative data-driven multi-objective optimization (MOO) method is proposed for the loaded meshing transmission performances of aerospace spiral bevel gears. Data-driven tooth surface modeling is first used to obtain a curvature analysis of loaded contact points. An innovative numerical loaded tooth contact analysis (NLTCA) is applied to develop the data-driven relationships of machine tool settings with respect to loaded meshing transmission performance evaluations. Moreover, the MOO function is solved by using an achievement function approach to accurate machine tool settings output, satisfying the prescribed requirements. Finally, numerical examples are given to verify the proposed methodology. The presented approach can serve as a powerful tool to optimize the loaded meshing transmission performances with higher computational accuracy and efficiency than the conventional methods. [ABSTRACT FROM AUTHOR]

In order to explore the time-varying mesh stiffness and dynamic parameters of bevel gears with different surface roughness, the fractal dimension and characteristic scale coefficient are calculated to determine the fractal dimension of tooth surfaces of spiral bevel gears with rough features. Spiral bevel gears with distinct surface roughness are obtained by simulating the gear-cutting process, and after analysis, a dynamic differential equation for spiral bevel gears considering the surface roughness is proposed. By combining the differential equation with finite element analysis (FEA), the time-varying mesh stiffness of spiral bevel gears with various surface roughness is determined. FEA analysis yields the time-varying mesh stiffness under different surface roughness. The vibration velocity and acceleration of spiral bevel gears with different surface roughness are revealed by combining the time-varying mesh stiffness with the dynamic equation. The intricate relationship between gear surface microstructure and its mechanical behavior during engagement is thoroughly analyzed. A comprehensive dynamic parameter model is proposed to capture the influence of microtopological changes on gear dynamics. The results can offer valuable insights for the design and optimization of bevel gears, aiming to enhance their performance and durability. [ABSTRACT FROM AUTHOR]

The warm-forging technology of the spiral bevel gear (873 K–1073 K) was studied. Based on the rigid–plastic finite element method, a numerical simulation was carried out by using DEFORM V11.0 software to explore the influence of different process parameters on gear-forming quality and forming force in the process of warm forging. Taking into account the complexity of the geometry of spiral bevel gears and the diversity of the influence factors in the forging process, as determined through nine groups of numerical simulation experiments, this paper systematically analyzed the influence law of different forging speeds, die preheating temperatures, friction factors and workpiece heating temperatures on the effective stress and strain of spiral bevel gears. The best combination of process parameters with minimum forging force was obtained via the orthogonal experiment, which provides a theoretical basis for the optimization design of the precision forging process of spiral bevel gears and also provides a new idea for studying the precision-forging–forming process of other complex parts. [ABSTRACT FROM AUTHOR]

Although extensive research has been done on distortion of heat-treated steel parts, our understanding of heat-treated distortion in spiral bevel gears is far from complete. The cooling characteristics and phase transformation of spiral bevel gears during carburizing and quenching and the effect of quench rate on the uniformity of temperature and phase transformation have been investigated using a medium-alloyed Cr–Ni steel. A new thermodynamic-based model of MS (the start temperature of martensitic transformation) has been proposed, which incorporates both the effects of austenite grain size and carbon content gradient to investigate the kinetics of martensitic transformation during quenching. The effect of austenite grain size on MS was considered in the critical driving force calculation model for martensitic transformation, which includes terms for interfacial energy, strain energy and Hall–Petch energy. In addition, a new method was proposed to characterize the non-uniformity of temperature and martensite distribution across the tooth of the spiral bevel gear. The finite element method was utilized to solve the coupled carbon concentration field, temperature field and metallurgical field. Results show that the complex geometry of spiral bevel gears results in a significant degree of non-uniformity of temperature and phase transformation during carburizing and quenching. Higher quenching medium temperature can reduce the non-uniformity of temperature distribution, while the effect on the volume fraction of martensite formed is almost negligible. Research findings presented have the potential to benefit further research on distortions of spiral bevel gears. [ABSTRACT FROM AUTHOR]

A working prototype of a non-parallel shaft drive system inspired by the Ceramic Speed Driven system was developed. It consists of a driving wheel with bearings arranged coplanar to its outer diameter, which transmits power to a driven wheel with its axle positioned at 90 degrees to the driving axle. A graphical method obtained the tooth geometry on the driven wheel. Subsequently, a kinematic analysis was performed and it was found that the system behaves like a chain drive system, where the speed of the output shaft is not constant due to the polygonal effect. The driving and driven wheels were manufactured in resin by additive manufacturing and adapted to a workbench for mechanical testing. By measuring torque using a Prony brake, efficiency comparisons were made between the fabricated system and the spur and chain bevel gear drive systems. The proposed system was found to have similar efficiency to spur bevel gear drives and superior to chain drives. [ABSTRACT FROM AUTHOR]

As a transmission part for industrial application the manufacture of spiral bevel gear is particularly important. The present machining methods for manufacturing spiral bevel gears, including the so called five-cut method and completing method, have drawbacks such as low processing efficiency, requiring complex calculations and high requirements on the machine-tool performance, respectively. To solve the above problems, an equivalent completing method is proposed to process spiral bevel gear in this paper. Firstly the machine setting parameters by completing were translated from the Cradle-type hypoid generator to Cartesian-type hypoid generator and the workpiece is swing during process. CNC motion axes expression of Cartesian-type hypoid generator were expressed as sixth-order polynomial, the influences of coefficient on the tooth surface topology were researched. Then the method to machine spiral bevel gear was put forward by reducing the swing axis of workpiece, obviously a deviation of tooth surface was caused between theoretical and axis-reduced. As a response, a flank correction model was established and the other polynomial coefficients were adjusted to eliminate the deviation. Finally simulation and cutting experiment were carried out by a numerical example. The experimental results show that the proposed method is effective and feasible. The method proposed in this paper overcome and enrich the disadvantages of existing manufacture methods of spiral bevel gear. [ABSTRACT FROM AUTHOR]

Bevel gears find application in transmitting motion between unequally aligned shafts, typically forming a 90° angle relative to each other. Some of the several types that are available commercially are the straight bevel, the Zerol bevel, the spiral bevel, and the hypoid. Stainless steel, gray cast iron, titanium alloy and structural steel were used for the behavioural assessment. The design and modelling of the straight bevel gears were carried out using SolidWorks 2015, while ANSYS 18.2 was employed simulating to simulate the gears' stress and deformation. The 3D solid model generated using SolidWorks was imported into ANSYS, where the analysis was conducted using the finite element software, ANSYS Workbench. Stress distribution plot, deformation plot, and equivalent strain plot were generated. The highest stress, measuring 73.536 MPa, became evident as the load concentrated near the base of the gear teeth. The finite element analysis revealed a minimal likelihood of gear failure, and the least deformation was observed in the structural steel configuration, resulting in a deformation of 8.2354 x 10^-3 mm. Consequently, the gear pair can successfully transmit 6 kW of power without experiencing any failures with a good safety factor. [ABSTRACT FROM AUTHOR]

The importance of diversified energy production lies in addressing the fuel shortage resulting from high prices, high temperatures, and environmental pollution associated with its production and consumption. Vibrational energy plays a crucial role in generating electrical power. This paper introduces a new concept based on utilizing the vibration forces of chimneys caused by wind and earthquakes. A mechatronic energy-absorbing system was designed, analyzed, and the output power was calculated using SolidWorks and Matlab programs. The design of the Regenerative Damping Chimney (RDC) primarily focuses on converting vibrations into rotational movement of the chimney, which is generated by wind forces. This is achieved by using a metal rope and pulleys to transmit motion to a set of gears. The opposite direction rotation is facilitated by bevel gears and clutches, and a planetary gearbox is employed to increase the rotation of the DC 24 V 400 W generator. The use of a high-watt generator aims to enhance energy production and the damping factor, ensuring the stability of the chimney during storms and vortex winds. The results show the efficiency of 35 % may reach 45 % watts under test to verify that the proposed system is effective and suitable for chimneys and renewable energy applications in factories and companies. [ABSTRACT FROM AUTHOR]

Spiral bevel gears are key components in many mechanical transmission systems, and their production is always of great interest to industry, and hence, subjected to intensive research widely. The present machining methods for manufacturing spiral bevel gears, including the so called five-cut method and completing method, have drawbacks such as low processing efficiency, requiring complex calculations and high requirements on the machine-tool performance, respectively. To solve the above problems, the duplex spread blade method is proposed. Firstly, geometric parameters and machine setting parameters were comprehensively considered, and then a modified reference point was selected to deduce the machine setting parameters. Tooth contact analysis (TCA) model considering misalignment was established to check meshing performance, the influence of cutter parameters and misalignment on meshing performance was studied. As the research reveals that the cutter radius has an effect on the bias of contact trace, cutter number has an impact on the position of contact pattern. The experimental results are consistent with the theoretical which verified the effectiveness and feasibility of the proposed method. The results of this paper have a guiding significance and enrich the machining method for spiral bevel gear. [ABSTRACT FROM AUTHOR]

This paper presents an ultimate motion methodology of a face-milling spiral bevel gear pair to synthesize the mating tooth surfaces with a predesigned fourth-order motion curve. The methodology is to control some contact points along the contact path in the process of tooth contact analysis via application of an extended local synthesis which permits some transmission errors rather than zero at the concerned contact point. The modified offset motion correction is selected to demonstrate the proposed methodology. Applied torque corresponding to an elastic approach of 0.00635 mm at the mean contact point is calculated and the loaded tooth contact analysis is performed. Numerical results show that the extended local synthesis can effectively control the transmission errors on the predesigned fourth-order motion curve at arbitrarily predesigned contact points along the contact path of the spiral bevel gear pair. The tooth contact pattern for the actual tooth pair is scattered into three segments since the rotational motion of the driven gear at any instant angular position is dependent on the tooth pair with the least transmission error among the three adjacent tooth pairs. The actual tooth contact patterns of the spiral bevel gear pair become continuous when meshing tooth surfaces are elastically deformed. [ABSTRACT FROM AUTHOR]