In recent years, a new type of gear named Logix gea r was developed. Actually, the tooth profile of this new type of gear is composed of lots of micro-segment involute curves, and on the profile, there exist lots of p...In recent years, a new type of gear named Logix gea r was developed. Actually, the tooth profile of this new type of gear is composed of lots of micro-segment involute curves, and on the profile, there exist lots of points, which their relative curvatures are equal to zero. This can result in the sliding coefficient smaller between two meshed Logix gears, and the mesh ch aracteristic becomes almost rolling transmission from sliding transmission accor dingly. So, this new type of gear has lots of advantages such as higher contact intensity, longer useful life and can easily realize power transfer of bigger tr ansmission ratio than standard involute gear. Study results showed that the cont act fatigue strength is 3 times larger, the bend fatigue strength is 2.5 times l arger, and the minimum tooth number can be decreased to 3, much smaller than tha t of standard involute gear. In this paper, following studies had been done: 1) The formation principle of Logix gear tooth profile was studied. The theoreti cal models describing the geometrical formations of this type of gear and its re lative Logix rack had been deduced. 2) While cutting a Logix gear, its tooth profile is decided by its normal tooth profile of Logix rack. Besides the basic parameters of standard involute gear, L ogix rack has its own specific parameters such as preliminary pressure angle, re lative pressure angle, and preliminary referential circle radius etc. So, the in fluence of connatural parameters of Logix rack on the tooth profile of Logix gea r had been farther studied. Reasonable selection for these parameters had been d iscussed. 3) Several kinds of transition curves for gear’s tooth profile had been introdu ced, its selection used by Logix gear had been described, and also its mathemati cal description model had been deduced. 4) The mesh theories of Logix gears had been developed. It had been proved that the transmission performance between Logix gears coincides with E-W theorem as that of ordinary standard involute gears. The formula calculating superposition coefficient was deduced according to its definition. Different from standard inv olute gears, the parameter of gear number has no effect on the superposition coe fficient of the Logix gears. Accordingly, bigger ratio transmission can be acqui red by means of decreasing the gear number, and its minimum gear number can be r eached to 3, much smaller than the minimum gear number of ordinary standard invo lute gear: 14～17. This is very important to realize the miniaturization of prod uction design. 5) The CAD special software was developed to design all kinds of Logix gears, an d a solid design example was offered. To sum up, by means of above study, the system info about Logix gear had been de veloped and enriched. This has most significant impact on its widely promotion a nd practical application, on the improvement of carrying capacity, miniaturizati on, and life of kinetic transmission products.展开更多
研究了基于形变理论的板料成形一步模拟法(又称为反算法).采用由CST(ConstantStrain T riangu lar)薄膜单元和DKT 6(D iscrete K irchhoff T riangu lar)板单元组合而成的DKT 12壳单元,既可以考虑面内薄膜力的作用,也可以叠加弯曲效应...研究了基于形变理论的板料成形一步模拟法(又称为反算法).采用由CST(ConstantStrain T riangu lar)薄膜单元和DKT 6(D iscrete K irchhoff T riangu lar)板单元组合而成的DKT 12壳单元,既可以考虑面内薄膜力的作用,也可以叠加弯曲效应对单元的影响.引入Barlat提出的6个应变率分量表示的塑性势函数,可以更好地描述板料面内各向异性.用弧长展开法获得初始解,并利用反向变形法对其进行改进,增强了求解的稳定性,提高了计算精度.盒形件的拉深实例证明,该改进的方法可以更为有效地模拟实际变形情况,分析结果具有较高的可信度.展开更多
文摘In recent years, a new type of gear named Logix gea r was developed. Actually, the tooth profile of this new type of gear is composed of lots of micro-segment involute curves, and on the profile, there exist lots of points, which their relative curvatures are equal to zero. This can result in the sliding coefficient smaller between two meshed Logix gears, and the mesh ch aracteristic becomes almost rolling transmission from sliding transmission accor dingly. So, this new type of gear has lots of advantages such as higher contact intensity, longer useful life and can easily realize power transfer of bigger tr ansmission ratio than standard involute gear. Study results showed that the cont act fatigue strength is 3 times larger, the bend fatigue strength is 2.5 times l arger, and the minimum tooth number can be decreased to 3, much smaller than tha t of standard involute gear. In this paper, following studies had been done: 1) The formation principle of Logix gear tooth profile was studied. The theoreti cal models describing the geometrical formations of this type of gear and its re lative Logix rack had been deduced. 2) While cutting a Logix gear, its tooth profile is decided by its normal tooth profile of Logix rack. Besides the basic parameters of standard involute gear, L ogix rack has its own specific parameters such as preliminary pressure angle, re lative pressure angle, and preliminary referential circle radius etc. So, the in fluence of connatural parameters of Logix rack on the tooth profile of Logix gea r had been farther studied. Reasonable selection for these parameters had been d iscussed. 3) Several kinds of transition curves for gear’s tooth profile had been introdu ced, its selection used by Logix gear had been described, and also its mathemati cal description model had been deduced. 4) The mesh theories of Logix gears had been developed. It had been proved that the transmission performance between Logix gears coincides with E-W theorem as that of ordinary standard involute gears. The formula calculating superposition coefficient was deduced according to its definition. Different from standard inv olute gears, the parameter of gear number has no effect on the superposition coe fficient of the Logix gears. Accordingly, bigger ratio transmission can be acqui red by means of decreasing the gear number, and its minimum gear number can be r eached to 3, much smaller than the minimum gear number of ordinary standard invo lute gear: 14～17. This is very important to realize the miniaturization of prod uction design. 5) The CAD special software was developed to design all kinds of Logix gears, an d a solid design example was offered. To sum up, by means of above study, the system info about Logix gear had been de veloped and enriched. This has most significant impact on its widely promotion a nd practical application, on the improvement of carrying capacity, miniaturizati on, and life of kinetic transmission products.
文摘研究了基于形变理论的板料成形一步模拟法(又称为反算法).采用由CST(ConstantStrain T riangu lar)薄膜单元和DKT 6(D iscrete K irchhoff T riangu lar)板单元组合而成的DKT 12壳单元,既可以考虑面内薄膜力的作用,也可以叠加弯曲效应对单元的影响.引入Barlat提出的6个应变率分量表示的塑性势函数,可以更好地描述板料面内各向异性.用弧长展开法获得初始解,并利用反向变形法对其进行改进,增强了求解的稳定性,提高了计算精度.盒形件的拉深实例证明,该改进的方法可以更为有效地模拟实际变形情况,分析结果具有较高的可信度.
