Straight Bevel Gears Research Articles

Research on Plasticity Shaped Technology of Rear Axle Gear of Motorcar

Rear axle spiral bevel gear of motorcar, as its special shape structure , alveolar much deeper than straight bevel gear , and has spiral angle effect , therefore, extrusion of rear axle gear than extrusion of straight bevel gear is much more difficult , deal with the problems, have made closed extrusion new technology of rear axle gear , designed new type die structure, die adopt fluctuateing concave model level bisection ， pre-stressed composite concave model structure , concave model and model core floating , parts have no fly side , tooth surface can reach the level of rough milling ,higher production efficiency and life of die , satisfied production requirements. Process test showed that compared with the open die , required extrusion distortion force reduced 50% , increase material utilization 15%, debase electric power consumption 50%, with significant economic benefits .

The Modification Design of Involute Straight Bevel Gear

Because of the impact of installation error, manufacturing error and elastic deformation and thermal deformation and other factors, the straight bevel gear pair will appear serious phenomenon of meshing interference and impact and uneven load in meshing process, so it is necessary to design suitable modification tooth to improve gear pair's transmission performance and enhance its bearing capacity. In this paper, considering elastic deformation of gear pair, using orthogonal design to obtain the optimal isometric modification parameters, and then using the optimal isometric modification parameters and symmetric crowned modification parameters to modify tooth separately. Three-dimensional solid models of standard gears and modification gears are established by SolidWorks, then dynamic contact FEA is carried out based on ANSYS/LS-DYNA. The simulation results show that the optimal isometric modification can reduce meshing impact and avoid “end contact” and homogenize tooth load distribution more effective compared to symmetric crowned modification for straight bevel gear.

Equivalent Conversion Calculation of Straight Bevel Gear’s Mesh Stiffness

Based on analyzing the defects of the usual equivalent conversion methods,the paper presents a new equivalent conversion method for mesh stiffness calculation of straight bevel gears of the small teeth number and diameter. By means of comparison among the different calculation methods,the conclusions can be obtained as follow:The straight bevel gear’s mesh stiffness value calculated by the new equivalent conversion method and Yishikawa formulae improved is more enhanced obviously than one calculated by the usual equivalent conversion methods and Yishikawa formulae ,and its change trend is closer to the numerical calculation value than the change trend of the straight bevel gear’s mesh stiffness value calculated by the usual equivalent conversion methods and Yishikawa formulae.

Computational estimation of wear, service life, and efficiency of the straight orthogonal bevel gear

The substantiation of experiment-calculated method for estimation of the wear, service life, and efficiency of the straight orthogonal bevel gear is given.

Experimental Tensile Study on the Behavior of Composite Material with Roving Waviness

This paper describes the materials and the methods used to make a tensile test of composite materail. The experimental study is conducted to observe the crashing behavior of composite material using different types of material namely; glass/epoxy carbon/epoxy and jute/epoxy specimens. Then, the behavior of the composite specimens is observed to determine the best material that produced the highest mechanical properties to be used as a material for a straight bevel gear in robotic arm application. The experimental work has been divided into two stages. The first stage is the experimental process, which involves fabrication of the specimens for the tensile test. The second stage is the preparation of specimens for the tensil test.

Generation and TCA of Straight Bevel Gear Drive with Modified Geometry

In order to reduce the sensitivity of straight bevel gear drives to misalignment, a new geometry of such gear drives is proposed in longitudinal direction. Point contact instead of line contact of tooth surfaces is achieved by longitudinal crowning of pinion tooth surface. The tooth surface modeling and tooth contact analysis (TCA) of straight bevel gear drives have been established. TCA program of a pair of straight bevel gears was performed in MATLAB and tooth bearing contact and transmission errors were obtained.

Grinding Cutter Design of Involute Straight Bevel Gear Based on Central Projection Method

In order to establish precise grinding cutter model of straight bevel gear, this study projects the spherical involute that forms tooth profile of bevel gear into the involute of circle approximately, and makes a simulation model database of bevel gear according to the principle of mechanical design on the basis of CAD mapping software. With the central projection method, processing devices and cutters of involute straight bevel gear can also be designed which has no concern with modulus. The results show that the establishment of simulation database and processing cutters can greatly facilitate the design and processing of straight bevel gear, greatly reduce the design and finishing costs, and is also helpful to teaching training of gear.

Computerized design of advanced straight and skew bevel gears produced by precision forging

The computerized design of advanced straight and skew bevel gears produced by precision forging is proposed. Modifications of the tooth surfaces of one of the members of the gear set are proposed in order to localize the bearing contact and predesign a favorable function of transmission errors. The proposed modifications of the tooth surfaces will be computed by using a modified imaginary crown-gear and applied in manufacturing through the use of the proper die geometry. The geometry of the die is obtained for each member of the gear set from their theoretical geometry obtained considering its generation by the corresponding imaginary crown-gear. Two types of surface modification, whole and partial crowning, are investigated in order to get the more effective way of surface modification of skew and straight bevel gears. A favorable function of transmission errors is predesigned to allow low levels of noise and vibration of the gear drive. Numerical examples of design of both skew and straight bevel gear drives are included to illustrate the advantages of the proposed geometry.

Design and manufacturing of a straight bevel gear in hot precision forging process using finite volume method and CAD/CAE technology

Forging simulation offers significant cost and time advantages by providing detailed insight into the forging process before tool selection and process decisions are made on the shop floor. Process data such as material flow, stresses, strains and temperature are readily accessible to a user at any point throughout the simulation process, as well as at any location within the forged part. Potential defects such as laps and under-fill of die cavities can be easily identified and corrected before part production begins. In addition, the influence of the process conditions such as lubrication and pre-form can be easily quantified and assessed. In the present work, hot precision forging process of the straight bevel gear is simulated numerically using finite volume method and computer-aided design/computer-aided engineering technology. The required force for the forging process, as well as the final shape of the bevel gear, is determined through numerical estimation. The simulation results are confirmed through the comparison with the experimental data available in DIN standards. Finally, the pre-form dies, the final die, and the bevel gear are manufactured. It is concluded that this method can be effectively used to optimize the forging process to maximize the mechanical strength, minimize material scrap, and hence reduce the overall cost of manufacture.

Numerical Control Innovation for Double Cradle Straight Bevel Gear Milling Machine

The Y2726-type double cradle straight bevel gear milling machine has been widely used at home and abroad, it cut straight bevel gear to barrel-type teeth by gear generating motion method. To avoid changing and adjusting transmission system at cutting different gears, this paper presents an innovation project that utilizes four servo motors to drive rotation of two cradles and two work piece heads with computer numerical control technology. Most transmission chains are removed. The generating motion of gear cutting is finished by interpolation of two servo motors controlled by CNC system. The producing efficiency is improved over 50% and the precision of manufactured gear is reached to class of seven.

H34 すぐばかさ歯車の回転伝達誤差に関する研究(H3歯車)

H34 すぐばかさ歯車の回転伝達誤差に関する研究(H3歯車)

The Straight Bevel Gear with Equal Conjugate Curvature

Inspired from the serious plastic deformation of some gears with heavy power transmission in practical usage in metallurgical industry, we believe that there must exist some kind of gear profile which is most suitable in both the contact and bending fatigue strength. From careful analysis and deep drawing investigation, we think that it is the profile of equal conjugate curvature with high order of contact, and analyzed the forming principle of this kind of profile. The contact stress is so low that even the Hertz theory, with which the contact stress can be calculated for most of the gearing, is invalid. This paper is aimed research how to calculate the contact stress of this kind of gearing.

Method for the evaluation of wear and durability of involute conical straight-bevel gears

A new computational model is proposed for the investigation of the kinetics of wear of teeth of straight-bevel gears. The model is used to assess wear and establish the regularities of its behavior along the length of the gear.

Accuracy Measurement and Evaluation of Straight Bevel Gear Manufactured by End Mill Using CNC Milling Machine

Straight bevel gears are usually manufactured with various machines and systems, and the tooth profiles are produced by grinding or machining by means of a tool with many cutting edges. In recent years, the straight bevel gear has been manufactured by an end mill using a computer numerical control (CNC) milling machine because the use of the auxiliary apparatus, special cutters, and special machine tools is not needed. Using this method, the gear manufacturing with high accuracy is an important problem. In this paper, the coordinate measurement of the straight bevel gear manufactured in this method is performed and the gear accuracy is evaluated. The tooth profiles of the straight bevel gear generated by a quasi-complementary crown gear instead of a conventional complementary crown gear are introduced. For this study, the tooth profiles of the straight bevel gear were modeled using a 3D computer-aided design system and the gear was manufactured by an end mill using a CNC milling machine based on a computer-aided manufacturing process. Afterward, the coordinates of many points on the gear tooth surfaces were measured at random using a coordinate measuring machine. This coordinate measurement provides the information about the factors related to the gear accuracy such as pressure angle, tooth angle error, workpiece setting angle, apex to back, and so on. Therefore, the values of the above factors were estimated and were compared with the theoretical ones, respectively.

DESIGN AND MANUFACTURE OF STRAIGHT BEVEL GEAR FOR PRECISION FORGING DIE BY DIRECT MILLING

In the manufacture of straight bevel gears, a precision forging method has been mainly used in recent years and the precision forging die has been usually manufactured using electric discharge machining. However, it is difficult to content the high productivity and low manufacturing cost using electric discharge machining because the gears are produced through a process of several steps. In this article, a design and manufacture of a straight bevel gear for a precision forging die by direct milling is developed in order to improve the productivity and manufacturing cost for the gear production. The tooth profile of a straight bevel gear generated by a quasi-complementary crown gear instead of a usual complementary crown gear is introduced. For this study, first the numerical coordinates on the tooth surface of the straight bevel gear were calculated and the tooth profiles were modeled using a 3D-CAD system. Afterward, the direct milling of the precision forging die of the straight bevel gear in the hardened state was carried out using a CNC milling machine based on a CAM process through the calculated numerical coordinates.

크라운 치형을 갖는 직선 베벨기어의 제작 및 검증을 위한 CAD/CAM 시스템 활용

The straight bevel gear for automobile part has been manufactured by the cold forging instead of the gear machining tool for the mass production. The application to CAD/CAM system has been necessary in order to develop the precision product quickly by forging through the minimization of trial and error and confirm the reproducibility. In the study, the straight bevel gear with the crown teeth has been modelled by the CAD/CAM system. The master gear after the gearing test has been machined after the modelling, NC data generation and verification. The die for forging and the jig for machining has been manufactured using the master gear.

Research on basic principle of moulding-surface conjugation

Abstract The tooth surfaces of spur gear, straight bevel gear, involute helical gear, Wildhaber worm and Wildhaber–Novikov gear are generated by moving a generator (a straight-line or a circular-arc) along a directrix (a trajectory curve), and their surface normals at all points of the same generator are coplanar. In geometric terms, the surfaces with such geometric properties are called moulding surface. When a pair of conjugate surfaces is moulding surfaces and their instantaneous contact-line is the common generator, this case is termed as moulding-surface conjugation. In this paper, the basic principles of this conjugation are developed. Based on the shape of the generators, this conjugation is classified into three types, and corresponding conjugate conditions are investigated. In order to examine the existence of conjugation, the structure conditions, embodying the transmission types and the characteristics of the directrix, are discussed. Moulding-surface conjugation can be studied by means of a pair of directrixes, so that the process of discussion is simplified. This conjugation can also be studied with the generating surface by introducing the indirect generating method, which establishes direct contact between the design and manufacture of tooth surface. These researches lay the foundation for transforming the principle of moulding-surface conjugation into the practical application.

Effect of Shot Peening on the Improvement of Durability of Bevel Gear

Shot peening generate compressive residual stress, which reduces repeatedly assessed tension stress and increase fatigue life. In this paper, the fatigue characteristics are evaluated according to shot peening condition for the real differential gear. The specimen is a straight bevel gear which transmits rotation of engine to running wheel and it is caburized. The bending fatigue test was done by the jig of our own making. The peening time was changed to find the best condition for the long fatigue life time. Fractography of specimen was analyzed by SEM to detect the location of initial crack. The experimental results show that the optimum peening condition is at 65m/s of shot ball speed and 8min of shot peening time. From the SEM image, the location of initial defect and direction of crack propagation were found

An Investigation on Manufacturing of the Straight Bevel Gear Using End Mill by CNC Milling Machine

Accurate manufacturing of bevel gears is an important problem for small workshops because the module milling cutters used for manufacturing are not accurate enough for the task. In this study, manufacturing of straight bevel gears is investigated by using end mills in CNC milling with a vertical machining center. By using this method, use of auxiliary apparatus, special cutters (such as the circular cutter, the rack cutter, etc.), and special machine tools are not required. For the study, first the straight bevel gear was modeled by Tredgold’s approach and manufacturing equations of the straight bevel gear were obtained. For the straight bevel gear manufacturing, a macro program was prepared and used. Afterward, the straight bevel gear was manufactured by using this program in a CNC milling machine, the Dyna 2900 machine. The results of the measurement data for a single tooth on the gear manufactured and the theoretical values are presented and discussed.

Theory on Designing Gears for Power Transmission (5th Report, A Pair of Paths of Contact realizing Equal Strengths of Tooth and Bearing on Both Drive and Coast Sides)

When a pair of paths of contact intersecting at the design point P0 are given on the normal plane Sn which is perpendicular to the relative velocity at Po, the conditions for the pair of paths of contact to realize equal strengths of tooth and bearing on both drive and coast sides under the same transmitted torque are discussed. Those conditions are expressed by 5 equations with 7 independent variables, which draw 5 separate reference paths of contact on the plane Sn geometrically. In designing gears, 3 variables (shaft angle, offset and gear ratio) are given, so that the equations have no solutions generally. However, cylindrical, crossed helical (including worm) and straight bevel gears can satisfy those conditions because their 5 reference paths of contact are superimposed and become at most one or two lines rectangular each other. Spiral bevel and hypoid gears with a rectangular shaft angle can not satisfy those conditions and their reference paths of contact vary according to the variables (offset, gear ratio and spiral angle), so that they have been designed as similar gears to ones whose performances are already assured by fixing the variables in some degree.