The Analysis of Bending Deformation of Cutter Tooth and Gear Tooth During Shaving Process

In this paper,the variation pattern of the contact point on cutter tooth and gear tooth is analyzed during gear shaving process. According to the shaving force measured by dynamometer, the deformation of cutter tooth and gear tooth at the contact point is calculated by appying the three dimension finite element method. The deformation curve of cutter tooth and gear tooth are obtained by analying deformation in shaving domain. It is the basis of studying relation between shaved amount and deformation.     

THE PRINCIPLE AND TECHNIQUE FOR GEAR PLANING BY DISCONTINUOUS GENERATING

The principle of gear planing by discontinuous generating is introduced and two kinds of techniques are presented based on this principle. Examples are given to show that both the accuracy and efficiency of the new techniques are higher and the cost is lower that those of gear hobbing and gear shaping.     

Worm wheel grinding method of convex pitch line non-circular gear

To overcome the precision machining difficulty of non-circular gear, a convex pitch curve of non-circular gear and worm grinding method is presented. Firstly, worm wheel is reduced to rack cutter and a rack machining convex pitch curves of non-circular gears sport model is set up. Then based on the structure of CNC worm wheel grinding machine tools and machining principle, electronic gear box of machine tools is designed and active and following axes are planned. At the mean time, the synchronous coefficient of machine tools between synchronization is deduced by machining principle of equal arc-length, and interaction models of grinding are established. At last, the worm wheel manual presetting cutter methods with non-circular gear are given and worm grinding wheel mounting angle, axial position and axial location parameter can be adjusted along the gear.     

Dynamic characteristics of multi-stage planetary gear trains in shield machine cutter drive

A purely torsional dynamic model of multi-stage planetary gear trains is developed to investigate the dynamic characteristics of the transmission system in shield machine cutter drive. In the model,phase difference between mesh stiffness and error among each stage caused by different initial mesh positions is considered,and other factors such as component bearing stiffness,time-varying mesh stiffness and error are considered as well. Inherent characteristic analysis shows there are more unique and diverse vibration modes in multi-stage planetary gear trains than in single-stage planetary gear trains. Through dynamic response analysis,time-domain and frequency-domain response of dynamic meshing force of each stage is obtained. As the frequency of exciting force of medium-speed and high-speed stage is in proximity to the natural frequency of the system,harmonic resonance tends to occur,which needs to be paid great attention to. Dynamic factors of each stage are also computed and prepare the ground for the dynamic optimizing design of planetary gear trains.     

Tooth contact analysis of helical beveloid gear with parallel axis

The study object of this paper is helical beveloid gears with parallel axis. Based on the gear Mshing Principles and the tooth-surface equations of pinion and gear,the mathematical model of tooth contact is developed under standard installation and installations with center distance error,axis error and multiple error respectively. The MATLAB solver is used to obtain the contact trace and the transmission error under different installing conditions and the comparative analysis is made. The results indicate that this gear drive is sensitive to axis installation errors,it forms the edge contact and cause the periodic transmission error. It can provide the foundation for designs and analysis of this gear transmission.     

Thermo-mechanical coupling analysis of shield cutter head under mud cake condition

Aiming at the cutter head thermal damage and other failure problems caused by shield cutter head mud formation in residue and clay soil,the problem of thermal-stress coupling of shield cutter head under the effect of mud in the tunnelling process is studied,and the cutter head temperature and thermal-stress distribution of coupling fields under mud effect are acquired. A shield cutter head three-dimensional finite element model is built by using software ANSYS and Solidworks. The results shows that when the mud is formed,the temperature rises sharply in a short time,which leads to a rapid increase of thermal stress to 168.2 MPa,at the same time,the maximum thermal deformation reaches 3.1 mm,then the center of cutter head is wrapped.     

Study and Application on the Abrasive Grinding Properties of Precision Abrasive Belt

The characteristics of work piece's surface under precision abrasive belt grinding are analyzed.A comprehensive understanding of the reason of low roughness value's surface is found out,which the edge of grain formed compact and crossed micro grinding marks that can compensate for the inconsistence of grinding mark's height in single grinding direction.The grinding test of gear shaft is done for the sake of doing research on the main factors of surface roughness in grinding quenching stainless steel.The results indicate that decreasing the vertical pressure is beneficial to(reduce) surface roughness of work piece,and the surface roughness also can reach the requirement of precision processing when steadily grinding.     

Design of Cross Section Curves of Counter-intermeshing Twin-screw Kneader and Milling Cutters Blade Profiles

Basing on the theory of engagement, a design has been done for a new type of counter-intermeshing twin-screw kneader. Profile of the screw includes arcs and its envelope lines, and the profile is smooth and continuous without cuspidal points. Milling cutter blade profiles also have been calculated and corrected for manufacturing the helical parts designed and getting the clearance acquired. There may be interference between the cutter and the workpiece, so interference check must be done to insure the milling cutter and screw will not be interfered.     

COMPUTER ALDED DESIGN OF FORMING CUTTER FOR REVISING INVOLUTE HELICAL

In this paper, a calculation method of forming cutter contour of involute helical with arbitrary easement is presented, the segmantal arcs of the best uniform approximation and tolerance to fit smoothly the cutter contour points are used the profile on the cross section of the helical is calculated and the design of the cutter is examined. The method can be used to design precision forming cutter of involute helical with the arbitrary easement. It is valuable in engineering application.     

Algorithm of Cutter Machining Position during Numerical Controlled Last Carving

Numerical control last making machine is a machine that is used to process shoe last. A new principle of numerical control machining shoe last is put forward aiming at the deficiency of current carving last system. On the basis of the principle, the algorithm of cutter machining position during numerical controlled carving last is analyzed in detail. The complex problem of the calculation of cutter machining positiion is resolved by applying spherical milling cutter that is often used in machining free_curve surface today and taking account of practical situation of the shoe last_making machine. At the same time, the calculation of cutter machining position is realized by program using Visual C++6.0. As a result, the calculation time of cutter machining position is reduced greatly and the efficiency of design is improved. Moreover, the process of carving last is agile and precision of carving last is ensured.     

Analysis on Three -Dimensional Numerical Controlled Last Machining Algorithm

On the basis of applying three dimensional discrete formative technology to describing last surface, working principle of numerical controlled last carving machine is briefly introduced. Then the algorithm of ascertaining milling cutter machining position during the machining process is analyzed in detail. We establish a three dimensional reference frame with spatial analytic geometry and obtain the spatial equation of milling cutter rotary surface. According to last machining character, we put forward a machining algorithm named Minimal Distance Method and is used to calculate the milling cutter machining position. Finally, the glabrous degree of last made by us has reached the conventional demand.     

Reference Efficiency of Planetary Gear Train

Reference efficiency of a pair of gear drive without planetary motion is the base to calculate efficiency of the whole planetary gear train. The authors find reference efficiency for speed increase is higher than that of the same drive used for speed reduction. This is different from the earlier viewpoint. New equations are derived for correctly calculating the reference efficiency of spur gear and helical gear with internal conjugate and external conjugate either in the state of speed increase or speed reduction respectively. The equations are also used to calculate efficiency of 2K-H planetary gear train.     

Dynamic optimization design of marine gear transmission system

A dynamic model of transmission system for a marine gear is established considering time-varying mesh stiffness, mesh damping and tooth composite error. The solution efficiency is improved by taking contact line length change of gear pair instead of instantaneous gear mesh stiffness change and making mesh damping and tooth surface equivalent to viscous damping. Multi-objective dynamic optimization design is put into practice to improve the marine gear transmission system using vibration acceleration and mass as target function. The results show that the optimization method can effectively reduce the vibration level and mass of marine gear.     

The Mode and Vibration Response of the Double Involute Gear

From the mathematical model of the double involute gear teeth surface at any corner position,we establish the model of the double involute gear with high precision and parameter in Pro/E,analyze and calculate the influence of natural frequency by the parameter of the double involute gear,analyze the frequency respond elementary.The conclusions reflect the gear's performance of dynamics,and provide the librate characteristic data for the design of double involute gear.     

Transmission model of higher-order elliptical bevel gearing and motion simulation for interference checking

Higher-order elliptical bevel gear is a typical form of the noncircular bevel gear transmission.Space spherical coordinate system of the bevel gear meshing is set up based on the meshing theory of space transmission.The varying relationship among the pitch curve,tooth profile and mesh lines are analyzed,and the equation of the gear tooth surface is developed with matrix method based on space coordinate transformation.The basic parameters of the noncircular bevel gear such as transmission ratio,modulus and the number of teeth are designed,and detailed analysis of the influence of the eccentricity on the relevant parameters is carried out as well.By using discrete numerical method and three-dimensional software,the mathematical model of the tooth profile and virtual physical model of the noncircular bevel gear are established,and then simulation on its motion and interference checking are performed.Finally,the approach for design,calculation and generation of the tooth profile is obtained and its correction has been verified by experiment.     

Separated Teeth Gear for Grinding Test

A kind of rational structure gear,separated teeth gear,in applied to grinding test.The contadiction between the heavy weight of the tested gear and the high precision of the measuring instrument is ideally solved.The gear is tested and verified by experiments.     

两级星型五分支传动静态均载分析

为分析两级星型五分支传动系统的均载问题,根据该系统构成功率流动闭环的特点,推导扭转角变形协调条件,结合力矩平衡条件,运用当量啮合误差理论,建立静态条件下的均载力学分析模型,求解得到均载系数,分析制造误差、安装误差、构件浮动对均载特性的影响。结果表明：太阳轮、内齿圈、星轮的误差单独影响均载特性时,内齿圈的误差影响最大,各构件制造误差影响的均载系数随时间做周期变化;太阳轮基于花键间隙浮动和内齿圈径向浮动,改善了均载特性,通过试验验证了理论分析的正确性。     

Gear classification and coding system oriented to product standardization

A 28-code gear classification and coding system based on the similarity principle of the Group Technology is set up and key technical characteristics of gear products are obtained. Then the geometrically and technically similar part families are clustered through analyzing the results of gear classification and coding, which lead to the formation of gear product standards. Through combining the core features of gear products with rolling bearing identification code sequence,a 11-product-identification-code system is designed and implemented in one special gear manufacturer enterprise.By employing Visual Basic6.0 and SQL Server2000,a Computer Aided Gear Classification and Coding System oriented to Client/Server was developed and exemplified by one specific case. Application results show that the system effectively groups gear products and efficiently categorize the technical characteristics of those having the same classification code into narrower classes,which propell the standardization of gear design and its production.The situation in which various gears are produced in small batches respectively will be improved by large batch production and finally the professional model of mass-customization production will be realized.     

Pitch error measurement of high-order oval bevel gear on three dimensional measuring machine

Based on the prototype workpiece which is manufactured according to the high-order oval gear envelope method,a measurement method of high-order oval bevel gear is proposed in order to verify the correctness of design and manufacture method for this gear pair. The mathematical model of measurement and evaluation is established according to the spatial gear engagement theory. Then the coordinate point set obtained from three-dimensional measuring machine is analyzed and filtered based on the actual measurement on prototype workpiece. Therefore,the ideal element is available. And then the aberration curve of pitch curve,individual circular pitch error and accumulated error can be obtained after analyzing the point set. Finally,the conclusion that the high-order oval bevel gear pitch error evaluation method is feasible can be obtained because the measurement and analysis result dovetailed basically with the theoretic calculation result.     

Meshing performance analysis of planar internal gear enveloping crown worm driving

A new worm driving,i.e. planar internal gear enveloping crown worm driving,is presented. Its mathematical model of meshing functions and teeth surface equations are established basing on the theory of differential geometry and gear mesh. Various types of the driving,the macroscopic meshing performance and the microcosmic meshing performance are analyzed. The results show that the inclination angle of generating plane determines the distribution of contact lines,the planar internal gear primary-enveloping crown worm driving has ideal lubrication property,and the planar internal gear second-enveloping crown worm driving has high loading capacity. The studies are practicably instructive for developing new worm driving with high loading capacity,ideal lubrication and small volume.