This study proposes a double-crown tooth surface modification technology that improves the load-carrying capacity of non-orthogonal helical tooth surface gears. The tooth modification is determined by a modified rack-cutter, and its feed motion is re...
The tooth profile modification of cycloidal gears is important in the design and manufacture of precision reducers or rotary vector (RV) reducers for robots. The traditional modification design of cycloidal gears is mainly realized by setting various...
This paper presents a comprehensive analytical–numerical model for the loaded tooth contact analysis of a cycloidal drive with tooth profile modifications (TPMs). Based on the principles of contact kinetics, elastostatic contact mechanics, and...
The China Bearing Reducer (CBR) is a single-stage cycloid reducer with a compact structure, primarily used in high-precision fields such as robotic joints and Computer Numerical Control (CNC) machine tool turntables, where strict requirements for tra...
This study presents a data-driven framework for determining the optimal gear tooth surface modification (crowning) to improve tolerance to angular misalignment (in-plane and out-of-plane). A nonlinear tooth contact analysis (TCA) model was employed t...
This article proposes a new method for optimizing tooth profile modification amounts of cycloidal reducers. By optimizing transmission error and transmission ratio fluctuation, the objective optimization function is determined, and the influence of o...
The rotary vector reducer presents high precision and load capacity characteristics. The shape of the cycloidal gear tooth profile in the rotary vector reducer significantly affects its performance. Meanwhile, the effect of the machining error on the...
A study on the dynamic characteristics of non-orthogonal helical face gears with higher-order tooth surface modification is presented in this article. The method of designing the non-orthogonal helical face gears with higher-order tooth surface modif...
Harmonic drives (HDs) with short flexspline (FS) always suffer from small meshing areas and severe stress concentration caused by large cone angles when a short FS is assembled and loaded. To address this issue, a tooth longitudinal modification meth...
Due to the existence of machining and installation errors, axis parallelism error of gear pairs occurs, which causes eccentric load and mesh in-out impact, thus weakening loaded transmission character. To solve this problem, the axis parallelism erro...
To address the issue of tooth surface twist, induced by lead modification during the form grinding of internal helical gears, this paper proposes a twist error compensation method based on tooth surface accuracy measurement and machine tool motion co...
To investigate the dynamic characteristics of a double-pressure-angle helical face gear transmission system, a digital tooth surface of a double-pressure-angle helical face gear, considering tooth surface modification, was established based on the ge...
A hybrid-excited doubly salient dual-PM machine (HE-DSDPM) was presented by using the structural multi-tooth modification for an improvement of torque production. The multi-tooth structure modification of HE-DSDPM was clearly described. The PM and st...
The current load distribution model for cycloid drives based on the Hertz contact stiffness typically assumes a two-dimensional planar problem without considering the tooth longitudinal modification effects, which fails to comply with the practical s...
Aiming at the deficiencies of the traction helical gear transmission system when the EMU is running at high speed, this paper proposes and designs a kind of arc toothed cylindrical gear adapted to the traction of higher speed EMU. A parametric arc to...
To enable effective regulation of the contact pattern location on tooth flanks and eliminate edge contact in cylindrical helical gear pairs, a novel asymmetric modification method that simultaneously addresses both the tooth profile and the tooth lea...
To address edge contact in non-circular gears arising from installation errors, a modification strategy represented by elliptical gears and driven by an ease-off topological surface is proposed. A tooth surface model for non-circular gears was first...
Based on the three-dimensional (3D) finite element method (FEM) and Taguchi method (TM), this paper analyzes the tooth surface contact stress (TSCS) of spur gears with three different influence factors: tooth profile deviations (TPD), meshing errors...
The tooth surface geometry of harmonic gears directly affects the transmission accuracy and service life. Traditional design methods may cause tooth profile distortion when changing the radial deformation coefficient, which limits their application....
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 metho...
As key components to transmit power and motion between intersecting shafts, it is necessary to design feasible tooth axial modification to improve the meshing performance and bearing capacity of straight bevel gears. The main purpose of this paper is...
Internal helical gear pairs are sensitive to manufacturing and assembly errors, loading deformation, which can result in vibration and noise. Three-dimensional topological modification of tooth surfaces is available to reduce this sensitivity. A 3D t...
The tooth flank distortion error occurring during the form-grinding (FG) of an involute helical gear can significantly compromise transmission performance. Conventional research approaches often focus on single-parameter optimization—either the...
Tooth flank twist is a common phenomenon in the helical crowning modification of helical cylindrical gear, which reduces the performance of the gear. At present, the measurement of tooth flank twist is still in the stage of replacing surface with lin...
The operating conditions of the drum shearer are very complex, and its ranging arm gear system often suffers from gear scuffing and wear. Gear scuffing is caused by the adhesive wear, which is due to the instantaneous friction and flash temperature o...
In order to enhance the load-bearing capacity of the involute beveloid gear pair, this study proposes research on improving the contact stress through axial modification. Under the condition of segmented parabolic axial modification, the mathematical...
Spiral bevel gears are used in a wide range of industries, such as automotive and aerospace, to transfer power between intersecting axes. However, a certain level of vibration is always present in the systems, primarily due to the complex dynamic for...
In this paper, novel non-involute cylindrical gears are designed based on a curved path of contact. Firstly, a parabolic curve is predesigned as the contact path of novel gears. Then, the tooth profiles of the novel gears are calculated using differe...
Time-varying mesh stiffness (TVMS) of the internal mesh transmission is a significant source of excitation that causes vibration and noise in planetary gear systems, and is also an important parameter in dynamics analysis. Currently, the calculation...
To improve the working performance of battery electric vehicle (BEV) high-speed helical gear transmission under full working conditions, combined with Tooth Contact Analysis (TCA) and Loaded Tooth Contact Analysis (LTCA), the vibration model of singl...
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...
Cycloid drives are widely used in various mechanical systems due to their high reduction ratio, compact size, and high efficiency. Tooth surface wear is a major problem that affects the reliability and durability of cycloid drives. However, compared...
The presented contribution focuses its attention on the research on the influence of the angular setting in a hobbing mill on the adjustment of the tooth profile created by this technology. The aspect of influence from the angular settings in the hob...
Tooth development or odontogenesis is a complex morphogenetic process that requires tightly regulated interactions between the oral epithelium and mesenchyme of neural crest origin. In this narrative review, we compile existing knowledge regarding ge...
(1) This research paper aims to conduct a comprehensive review of the existing scientific literature on intentional dental modifications within the African population. By synthesizing and analysing studies, this paper aims to shed light on the preval...
Malocclusion arises from complex interactions among genetic, environmental, and developmental factors. While genetic contributions are well established, epigenetic mechanisms, including DNA methylation, histone modifications, non-coding RNAs, and RNA...
Due to the advantages of high transmission accuracy and high impact resistance, cycloid-pin gear drives are widely used in precision machinery. In the actual manufacturing and use process, a suitable clearance must be left between the cycloid gear an...
Reducing noise in electric multiple-unit (EMU) gearboxes demands prediction tools that are both rapid and reliable. Gear sound pressure levels vary sharply with micrometre-scale changes such as tooth repair, inclination, or profile relief, yet tradit...
An elastic transmission error (TE) compensation method for a rotary vector (RV) speed reducer is proposed to improve its transmission accuracy based on error sensitivity analysis. Elastic and geometric TEs of the RV speed reducer can be compensated b...
The interrelationships between periodontal disease, obesity-related hyperlipidemia and mechanical forces and their modulating effects on the epigenetic profile of periodontal ligament (PdL) cells are assumed to be remarkably complex. The PdL serves a...
Amyotrophic lateral sclerosis (ALS) is the third most common neurodegenerative disorder and is sometimes associated with frontotemporal dementia. Charcot–Marie–Tooth disease (CMT) is one of the most commonly inherited peripheral neuropath...
The effects of addendum modification coefficient on the root stresses of spur gear are investigated. By considering positive and negative addendum modificated gears, distributions of root stresses are determined by the finite element method. The root...
Gear transmission systems are widely used to transfer energy and motion and to guarantee the accuracy of the entire machine system. The modification technique is a common method that improves the gear profile and reduces the transmission error. Based...
Due to their advantages of compact size, high reduction ratio, large stiffness and high load capacity, RV reducers have been widely used in industrial robots. The dynamic characteristics of RV reducers in terms of vibratory response and dynamic trans...
The importance of whole protein extracts from different types of human teeth in modulating the process of teeth biomineralization is reported. There are two crucial features in protein molecules that result in efficient teeth biomineralization. First...
Background: This study aimed to evaluate the agreement among different evaluators in assessing smile esthetics from frontal-view photographs of the lower third of the face during smiling, and afterwards to determine thresholds of perceptibility and a...
In the machining process of high reduction ratio hypoid gears (HRHGs), cutter tool geometry errors (CGE) and machine tool setting parameters errors (MSE) significantly affect tooth surface accuracy. Existing studies mainly focus on analyzing the effe...
Orthodontic tooth movement (OTM) relies on mechanical force-induced bone remodeling. As a metabolic intermediate of glycolysis, lactate has recently been discovered to participate in bone remodeling by serving as a signaling molecule. However, whethe...
Dental wear provides valuable evidence for reconstructing past human behaviour, including diet abrasiveness and non-masticatory activities such as the use of teeth as a “third hand”. This study investigates activity-induced dental modific...
The current loaded tooth contact analysis of cycloid drives based on the assumption of theoretical positions of ring pins ignores the deviations caused by manufacturing errors and elastic deformations, which are not in agreement with reality. To fill...
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