Although a great deal of research has been dedicated to the synthesis of spiral bevel gears, little related to reverse engineering can be found. An approach is proposed to reverse the machine-tool settings of the pini...Although a great deal of research has been dedicated to the synthesis of spiral bevel gears, little related to reverse engineering can be found. An approach is proposed to reverse the machine-tool settings of the pinion of a spiral bevel gear drive on the basis of the blank and tooth surface data obtained by a coordinate measuring machine(CMM). Real tooth contact analysis(RTCA) is performed to preliminary ascertain the contact pattern, the motion curve, as well as the position of the mean contact point. And then the tangent to the contact path and the motion curve are interpolated in the sense of the least square method to extract the initial values of the bias angle and the higher order coefficients(HOC) in modified roll motion. A trial tooth surface is generated by machine-tool settings derived from the local synthesis relating to the initial meshing performances and modified roll motion. An optimization objective is formed which equals the tooth surface deviation between the real tooth surface and the trial tooth surface. The design variables are the parameters describing the meshing performances at the mean contact point in addition to the HOC. When the objective is optimized within an arbitrarily given convergence tolerance, the machine-tool settings together with the HOC are obtained. The proposed approach is verified by a spiral bevel pinion used in the accessory gear box of an aviation engine. The trial tooth surfaces approach to the real tooth surface on the whole in the example. The results show that the convergent tooth surface deviation for the concave side on the average is less than 0.5 μm, and is less than 1.3 μm for the convex side. The biggest tooth surface deviation is 6.7 μm which is located at the corner of the grid on the convex side. Those nodes with relative bigger tooth surface deviations are all located at the boundary of the grid. An approach is proposed to figure out the machine-tool settings of a spiral bevel pinion by way of reverse engineering without having known the theoretical tooth surfaces and the corresponding machine-tool settings.展开更多
In order to lucubrate the rolling characteristic of the two stands reversible cold rolling mill and establish the tension and thickness control strategy, the steady-state characteristic simulating program was establis...In order to lucubrate the rolling characteristic of the two stands reversible cold rolling mill and establish the tension and thickness control strategy, the steady-state characteristic simulating program was established using the steady-state continuous rolling theory. The influences of each factor on exit thickness under different tension control methods were analyzed. The results show that, the influence of the entry stand gap on exit thickness is significant and it changes little with different tension control methods. As a result, the entry stand gap can be used as the main control method of exit thickness, whereas rolling speed of any stand and roll gap of the exit stand can be used to adjust the inter-stand tension. The results are beneficial for thickness and tension control of the two stands reversible cold rolling mill.展开更多
For entire roller embedded shapemeter roll, the relationship between the value of interference fit and the sensor pre-pressure, and the pressure transfer performance of shapemeter roll were analyzed by elasticity theo...For entire roller embedded shapemeter roll, the relationship between the value of interference fit and the sensor pre-pressure, and the pressure transfer performance of shapemeter roll were analyzed by elasticity theory during the cold reversible rolling process. Considering the influence of strip temperature on the interference fit, the distributions of contact pressure of the framework's top surface and the sensor pre-pressure on different values of interference fit were analyzed by the finite element technology. The results show that the contact pressure of the framework's top surface and the sensor pre-pressure increase with the increase of the value of interference fit. When the value of interference fit is between 0.05 mm and 0.09 mm, roll body's inner hole surface, the framework and pressure magnetic sensitive component don't separate from each other, and the sensor works in the linear segment of characteristic curve, so the normal operation of shapemeter roll is guaranteed.展开更多
In the given work results of researches asymmetric rolling on reversive mill 5000 are considered. By definition of boundary modes of asymmetry and an opportunity of application results of precomputations are resulted ...In the given work results of researches asymmetric rolling on reversive mill 5000 are considered. By definition of boundary modes of asymmetry and an opportunity of application results of precomputations are resulted in production for various circuits of rolling. Results of influence of asymmetric rolling on physic and mechanical properties, structure and geometry hot sheets are shown, recommendations to introduction of modes of asymmetry in a production cycle of manufacturing of sheet-rolling production of the improved quality are展开更多
The feasibility of improving the overall performance of medium Mn steels was demonstrated via tailoring the initial microstructure and cold rolling reduction. The combined effects of cooling patterns after hot rolling...The feasibility of improving the overall performance of medium Mn steels was demonstrated via tailoring the initial microstructure and cold rolling reduction. The combined effects of cooling patterns after hot rolling （HR） and cold rolling （CR） reductions show： （1） as the cooling pattern varied from furnace cooling （FC） to oil quenching （OQ）, the intercritically annealed microstructure was dramatically refined and the fraction of recrystallized ferrite dropped, regardless of CR reductions. This resulted in both high yield/ultimate tensile strengths （YS/UTS） but low total elongation to fracture （El）; （2） as the CR reduction increased from 50% to 75%, the OQ-samples after annealing exhibited a more refined microstructure with relatively higher fractions of retained austenite and sub-structure, leading to higher YS and UTS but lower El; whereas the FC samples appeared to exhibit little difference in overall tensile properties in both cases. The differences in microstructural evolution with cooling patterns and CR reductions were explained by the calculated accumulated effective strain （eAES）, which was considered to be related to degrees of recovery and recrystallization of the deformed martensite （α＇）. The optimal tensile properties of -1 GPa YS and -40 GPa.% UTSxEI were achieved in the OQ-50%CR annealed samples at 650 ℃ for 1 h. This was quite beneficial to large-scale production of ultra-high strength steels, owing to its serious springback during heaw cold working.展开更多
基金supported by Aero Propulsion Test and Demonstration of Commission of Science and Technology and Industry for Nation Defense,China (Grant No. APTD-1001B)
文摘Although a great deal of research has been dedicated to the synthesis of spiral bevel gears, little related to reverse engineering can be found. An approach is proposed to reverse the machine-tool settings of the pinion of a spiral bevel gear drive on the basis of the blank and tooth surface data obtained by a coordinate measuring machine(CMM). Real tooth contact analysis(RTCA) is performed to preliminary ascertain the contact pattern, the motion curve, as well as the position of the mean contact point. And then the tangent to the contact path and the motion curve are interpolated in the sense of the least square method to extract the initial values of the bias angle and the higher order coefficients(HOC) in modified roll motion. A trial tooth surface is generated by machine-tool settings derived from the local synthesis relating to the initial meshing performances and modified roll motion. An optimization objective is formed which equals the tooth surface deviation between the real tooth surface and the trial tooth surface. The design variables are the parameters describing the meshing performances at the mean contact point in addition to the HOC. When the objective is optimized within an arbitrarily given convergence tolerance, the machine-tool settings together with the HOC are obtained. The proposed approach is verified by a spiral bevel pinion used in the accessory gear box of an aviation engine. The trial tooth surfaces approach to the real tooth surface on the whole in the example. The results show that the convergent tooth surface deviation for the concave side on the average is less than 0.5 μm, and is less than 1.3 μm for the convex side. The biggest tooth surface deviation is 6.7 μm which is located at the corner of the grid on the convex side. Those nodes with relative bigger tooth surface deviations are all located at the boundary of the grid. An approach is proposed to figure out the machine-tool settings of a spiral bevel pinion by way of reverse engineering without having known the theoretical tooth surfaces and the corresponding machine-tool settings.
基金Item Sponsored by National Basic Research Program of China (2011CB612204)Doctoral Scientific Research Fund of Taiyuan University of Science and Technology of China (20112007)
文摘In order to lucubrate the rolling characteristic of the two stands reversible cold rolling mill and establish the tension and thickness control strategy, the steady-state characteristic simulating program was established using the steady-state continuous rolling theory. The influences of each factor on exit thickness under different tension control methods were analyzed. The results show that, the influence of the entry stand gap on exit thickness is significant and it changes little with different tension control methods. As a result, the entry stand gap can be used as the main control method of exit thickness, whereas rolling speed of any stand and roll gap of the exit stand can be used to adjust the inter-stand tension. The results are beneficial for thickness and tension control of the two stands reversible cold rolling mill.
基金Project(2011BAF15B00)supported by the National Science and Technology Support Plan of ChinaProject(E2011203004)supported by the Hebei Provincial Natural Science Iron and Steel Joint Research Fund Program,China
文摘For entire roller embedded shapemeter roll, the relationship between the value of interference fit and the sensor pre-pressure, and the pressure transfer performance of shapemeter roll were analyzed by elasticity theory during the cold reversible rolling process. Considering the influence of strip temperature on the interference fit, the distributions of contact pressure of the framework's top surface and the sensor pre-pressure on different values of interference fit were analyzed by the finite element technology. The results show that the contact pressure of the framework's top surface and the sensor pre-pressure increase with the increase of the value of interference fit. When the value of interference fit is between 0.05 mm and 0.09 mm, roll body's inner hole surface, the framework and pressure magnetic sensitive component don't separate from each other, and the sensor works in the linear segment of characteristic curve, so the normal operation of shapemeter roll is guaranteed.
文摘In the given work results of researches asymmetric rolling on reversive mill 5000 are considered. By definition of boundary modes of asymmetry and an opportunity of application results of precomputations are resulted in production for various circuits of rolling. Results of influence of asymmetric rolling on physic and mechanical properties, structure and geometry hot sheets are shown, recommendations to introduction of modes of asymmetry in a production cycle of manufacturing of sheet-rolling production of the improved quality are
基金financially supported by the National Natural Science Foundation of China (Grant.No.51401050)the Fundamental Research Funding for the Central Universities (Grant.No.N160204001),China (A/Prof.Cai)supported by grants through the Australian Research Council (ARC) Laureate Fellowship (Prof.Hodgson)
文摘The feasibility of improving the overall performance of medium Mn steels was demonstrated via tailoring the initial microstructure and cold rolling reduction. The combined effects of cooling patterns after hot rolling （HR） and cold rolling （CR） reductions show： （1） as the cooling pattern varied from furnace cooling （FC） to oil quenching （OQ）, the intercritically annealed microstructure was dramatically refined and the fraction of recrystallized ferrite dropped, regardless of CR reductions. This resulted in both high yield/ultimate tensile strengths （YS/UTS） but low total elongation to fracture （El）; （2） as the CR reduction increased from 50% to 75%, the OQ-samples after annealing exhibited a more refined microstructure with relatively higher fractions of retained austenite and sub-structure, leading to higher YS and UTS but lower El; whereas the FC samples appeared to exhibit little difference in overall tensile properties in both cases. The differences in microstructural evolution with cooling patterns and CR reductions were explained by the calculated accumulated effective strain （eAES）, which was considered to be related to degrees of recovery and recrystallization of the deformed martensite （α＇）. The optimal tensile properties of -1 GPa YS and -40 GPa.% UTSxEI were achieved in the OQ-50%CR annealed samples at 650 ℃ for 1 h. This was quite beneficial to large-scale production of ultra-high strength steels, owing to its serious springback during heaw cold working.
