Three Roller Curvature Scotch Straightening Mechanism Study and System Design

AbstractDuring the process of straightening, hot rolled deformed bars rotate around autologous axis, which cause out of the vertical of straightening surface and the straightening precision is deduced. To solve the problem of the bars's rotation , parallel roller collocation scheme of hot rolled deformed bars with high speed and no scratches is presented. Based on the theory of elastoplasticity large deformation, elastic recovery torque variety during the setting out of coiled bars is analyzed in accordance with the triple-roller equal curvature rotation blocking straightening system. The mechanical model of bars in triple-roller is established and rotation blocking mechanism of the triple-roller equal curvature rotation blocking straightening system is researched. The results indicate that the system has the effect of consistent original curvature and rotation blocking toguarantee straightening precision and supply the demand of operation

Inflection moment calculation and resilience analysis of roller straightening

Based on elastic-plasticity theory and appropriate mathematical model, stress and strain of steel bars in arbitrary bending state during the process of straightening is analyzed to deduce original ratio of curvature, the included angle between original bending plane and inflection plane and inflection moment. Corresponding resilience is analyzed to come to a conclusion that rebound plane turn around neutral axis to inflection plane. Roller system configuration of three-roller equal curvature of hot rolled ribbed steel bar is proposed to solve the problem that the steel bar rotate around its own axis during the straightening course, so comprehensive circle straightening is accomplished and straightening precision is improved

Research on the transmission error of swing-rod movable teeth transmission system

Using the two-tooth difference swing-rod movable teeth transmission system satisfying the drive function of large optical instruments as the study object, the influence of each component error on system transmission error is analysed. Each component error is presented by the vector method, and then it is transformed into equivalent error in the direction of the meshing action line based on the equivalent meshing error principle. The instantaneous transmission ratio of the system is obtained by the instantaneous velocity center method, and the system transmission error model is established. Using numerical analysis, the influence of each component error on the system transmission error is obtained. The transmission error test platform is used to test and analyze the transmission error of the two-tooth difference swing-rod movable teeth transmission system. The research results show that the swing-rod length error and the wave generator eccentric error have a great influence on the transmission error of the system among the six types of error factors, so they should be strictly controlled during design, processing and assembly. This study provides a theoretical basis for the rational allocation of machining errors and assembling errors of the two-tooth difference swing-rod movable teeth transmission system

STUDY ON STEADY-STATE TEMPERATURE FIELD OF THE MESHING PAIR OF TWO-TOOTH DIFFERENCE SWING-ROD MOVABLE TOOTH DRIVE

Based on the basic theory of heat transfer and tribology,the calculation formulas of the friction heat flux density of meshing pair,the meshing tooth surface and the end face convective heat transfer coefficient with two-tooth difference swing-rod movable tooth drive are derived under the slip condition.A finite element model of the thermal analysis of the gear meshing pair is established,and the steady-state temperature field of the meshing pair under thermal balance state is calculated and analyzed by using the ANSYS finite element software.Combined with numerical simulation results,the influence of tooth profile design parameters on the temperature field is revealed.The result shows that:the steady-state temperature field of the meshing pair is determined collectively by the heat flux of the contact zone and the convection heat transfer coefficient of each surface.Because the temperature rise of sliding friction is larger,the maximum temperature appears in the center of the gear meshing face width of the center,the radius of the base circle radius has a great influence on the body temperature of the meshing surface,and the swing rod length is less affected.The research results lay the foundation for the study of the thermal deformation and thermal mechanical coupling characteristics of the meshing pair,so as to guide the dynamic design of the two-tooth difference swing-rod movable tooth drive

Teeth profile parameter design and transmission property analysis of external generating wave movable teeth transmission

A highly efficient integrated transmission unit – external generating wave movable teeth transmission − was proposed and two kinds of typical transmission types were researched. Fixed and moving coordinate systems were established based on movable teeth transmission theory. On the basis of the profile of a wave generator, the teeth profile equations of ring gear were deduced by using the transform matrix and profile enveloping principle. The effects of the teeth number of the ring gear, generating wave coefficient, and tooth profile coefficient on the profile of the ring gear were investigated. The formula for calculating curvature radius of the ring gear was given. The pressure angle formulas were deduced, and the change rule of the pressure angle extremum was researched to obtain a continuous transmission condition. The relationship between design parameters and performance effect was analysed based on the analysis of the curvature and pressure angle. The results show that the transmission precision reached 97.67%, and the proper design parameters could guarantee transmission performance. Those researches lay a theoretical foundation for the design and application of an external generating wave movable teeth title