Bending Stress Analysis on Backlash Adjustable Worm Transmission

The full name of variable tooth thickness plane worm gear transmission is. Backlash adjustable plane worm gear with variable tooth thickness enveloping worm transmission, which is a new kind of accurate power transmission that is intervenient between traditional motion transmission and power transmission. Tooth surface equations of the variable tooth thickness plane worm gear transmission are deduced based on the theory of engagement. Basing on the result, the authors create a finite analysis model of backlash adjustable variable tooth thickness plane enveloping worm with perfect tooth shape by using I-DEAS software, and then has done finite element analysis of backlash adjustable variable tooth thickness plane enveloping worm transmission. Finally, the author drew a conclusion about distribution of principal stress and load distribution between teeth, which offer some references for strength and performance analysis of worm transmission.     

Effect of Tooth Modification on Double Enveloping Worm Gearing

A method of modifying the double enveloping worm gearing with developable tooth surface has been proposed to reduce the sensibility of the worm gearing to the manufacturing errors. The tooth contact and kinematic precision of the modified worm gearing with manufacturing errors has been investigated by the TCA method. The results show that by the modification, the edge contact resulting from the manufacturing errors is avoided or effectively relieved,and the kinematic error of the worm gearing is obviously reduced.     

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.     

Analysis on Oylindrical Worm in Traction Machine and Modifications

Cone enveloping cylindrical worm in traction machine as instance, theoretical analysis on cylindrical worm transmission has been theoretically analyzed, and efficiency test and load capability test of traction machine with YJ240 cylindrical worm have been done on open power gear experimental instrument. According to the experimental data, it indicates cylindrical worm have some weaknesses on load capability, efficiency, adjustment possibility of tooth backlash and so on. Therefore, on purpose of improving integral performance of traction machine, face worm with variable tooth thickness may be used as primary drive mechanism in traction machine instead of cylindrical worm.     

白口铸铁机械性能研究及在农机制造中的应用(Ⅰ)

为了提高白口铸铁的冲击韧性等机械性能,扩大其在农机具上的应用范围,采用BZ变质剂对白口铸铁进行变质浇铸,并研究了变质剂对白口铸铁中碳化物的断网效果.试验结果表明,变质剂对于含碳量在3.2%以下、含铬量在12%以下的白口铸铁具有较好的断网效果.     

铸铁钻削加工分析研究

现代机械制造中,铸铁材料应用广泛,机械设备中的发动机壳体、汽车的底盘、机床的底座等设备都充分利用了铸铁材料的优越性。为了满足底座与设备间的连接作用,底座的装配面进行钻削加工,钻削加工是常见的机械加工方式,为了提高劳动生产率,保证加工质量,降低劳动强度,文章主要分析铸铁材料的钻削加工特点,刀具工艺参数和夹紧力计算,为铸铁材料的钻削加工提供科学依据。     

金优253免耕抛栽秧苗的根系生长与立苗特性

2003年早季和晚季在大田条件下．以常耕抛栽为对照．对金优253免耕抛栽秧苗的根系生长与立苗特性进行了研究。结果表明，与常耕抛栽秧苗相比，免耕抛栽秧苗前期立苗速度较慢，后期立苗速度较快，总的立苗时间相同，但免耕抛栽秧苗的立苗更易受不良气候的影响；免耕抛栽秧苗立苗期发根较多．但根系生长受阻，根系的总长度不及常耕抛栽秧苗；抛后1周内，抛栽秧苗根系活力经历了由低到高再到低的变化过程。当根系活性上升时，免耕抛栽秧苗上升速度慢；当根系活力下降时．免耕抛栽秧苗下降也慢。     

铸铁零件电弧喷涂前的喷砂预处理工艺研究

应用二次旋转组合试验进行试验设计，建立了喷砂距离、喷砂压力、喷砂角度与涂层和基体间结合强度的数学模型。通过降维分析法分析了双因素组合与结合强度之间的关系。结果表明：选用优化的预处理工艺进行粗化，可提高电弧喷涂涂层与基体铸铁的结合强度，满足一般使用要求。     

铸态珠光体球墨铸铁组织形态与性能

在普通球墨铸铁的基础上，加入Cu、Sb合金元素，通过余温正火工艺，获得铸态珠光体球墨铸铁。该铸铁的珠光体含量大于（等于）95％，渗碳体小于（等于）5％，抗拉强度可达700-850MPa，硬度为280-350HB，延伸率为3％～5％。扫描电镜及透射电镜分析表明，当加入0．5％Cu、0．02％Sb时，合金主要由珠光体与球状石墨组成，其中铸态珠光体层片间距变小，石墨球细小而均匀，铁素体的形成受到抑制。     

0.1%氧化苦参碱水剂防治菜青虫田间药效试验

由田间试验结果得知:0.1%氧化苦参碱水剂对菜青虫防效高, 防治持效期长.0.1%氧化苦参碱水剂80～200mL/hm2剂量施药3天后防效达94.36%～99.27%,施药7天后其防效仍达99.08%以上,与其他药剂相比效果明显,适宜施药剂量为150mL/hm2.施药后安全性调查表明,该药剂对作物无毒害,适合无公害蔬菜生产.