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.     

Mothematical Model for Planing of Precise and Hardened Gear

In this paper, the mathematical model for gear planing of precise and hardened gear is established. The computational charts and results for the tooth edge height,cutter edge contact length and cutter area are given out to improve the present planing technique.     

Optimum Compound Profile Modification of Cyclodal Gear

The analysis of the existing way and amount of profile modification of cycloidal gears at present showed that the equidistance and movedistance modification is in substance really to have the profile swelled up,and the rational modification way and amount is a swelling correction within the range of zero to some limit. This paper presents a new modifying way which is optimum compound modification at separate parts. The modified profile has the most simultaneously transmission teeth,even side clearance and the longest wear-life to forming crush dressing roll and is also easyly to NC machining.     

THE NEW SECTION PLANE OF NORMAL CYLIDRICAL WORM TOOTH FLAND ERROR ON THREE COORDINATE MEASURING MACHINE

The concept of "New Section Plane" has been proposed when the tooth flank error of normal cylidrical worm is measured on the three coordinate measuring machine .and it has been compared in many respects with the general" First Section Plane". It has been pointed out that "The New Section Plane" is superior to "The First Section Plane     

Study of Tooth Contact and Kinematic Precision on Cone-Generated Double Enveloping Worm Gearing

The tooth contact and kinematic precision of cone-generated double-enveloping worm gearing with machining and assembling errors have been investigated. The influence of different errors on driving quality has been discussed. The assembling method to reduce or eliminate the influences of machining errors on tooth contact and kinematic precision has been proposed.     

Intensity Comparative Analysis Based on Ideas Between Involute Gear and Double Involute Gear

Modeler and simulation modules in Ideas software are used to build the finite element models on involute gear and double involute gear with accurate tooth shape, and with the same design parameters and under the same loads, finite element contact analysis has been done. At last, the contact stress and bending stress on the two types gear transmission at the different meshing positions are solved out, and comparative analysis and study have been done. At the same time, that the ladder-shape tooth on the double involute gear how to influence contact stress and bending stress is emphatically analysed. All above offer the theoretical foundation that bring the double involute gear with ladder-shape tooth into the industry.     

Study on Mismatched Engagement of Hourglass Worm Gearing with The Worm Generated by A Cone and The Wheel Generdted by A Straight Profile Hob

A method to make the hourglass worm gearing with the property of mismatchedpoint contact has been proposed.The worm and the hob of the worm gearing is generated by a coneand a straight line located on the cone respectively. The basic principle of the worm gearing has beenanalysed. The formulas for calcultating the machining parameters has been obtained. And the toothcontact of the worm gearing has been investigated.The result shows that this worm gearing could getopint contact well.     

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.     

Dynamic Optimization of System Parameters For the Epicyclic Gear Drive with Internal Tooth

The epicyclic gear drive with internal tooth has been analysed,the formula has been also deduced for computing the inertial force and change of contact force,and the dynamic optimization of system parameters for the force of bearing has been carried,it has given a reliable proof to reduce the dynamic load and prolong the life of bearing of three ring type reducer.     

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.     

Study on Dynamical Characteristic of Epicyclic Gear Drive with Internal Tooth

The epicyclic gear drive with internal tooth is analysed,a dynamic analysis model which is based on the compatibility conditions of deformation is set up.On the basis of this model,the analysis of dynamics and kinematics is made,and the influence of design parameters on dynamical characteristic is also studied.     

THEORETICAL INVESTIGATION OF SPHERE RE-ENVELOPING HOURGLASS WORM GEARING

On the condition of avoiding the"undercutting,"and "sharpening" of worm tooth, it is now regarded as an important subject in the field of meshing principle studying of the "multiple-thread small reducation ratio" hourglass worm gearing with developable tooth surfaces to reduce the gorge pitch circle diameter of worm, raise meshing efficiency and strength of the wheel tooth and improve the unresonable structure of the pair. In this paper, a new type of hourglass worm gearing with developable tooth surfaces -"Sphere Re-nveloping Hourglass Worm Gearing" is studied. It shows that 4a satisfied result to above subject can be obtained if this worm gearing is applied.     

A STUDY OF THE OPTIMIZATION OF CIRCULAR ARC TOOTH PROFILE TRANSMISSION

For the first time, we point out the new idea that we can approximate the involute tooth profile transmission to circular arc tooth profile transmission. Looking upon it as a fourbar linkage we try to minimax the error of the velocity ratio and evaluate the strong-weak point of circular arc tooth profile transmission.     

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.     

书虱的种类,生物学特性及防治

对书虱进行研究，不仅能为防治提供科学依据，具有较大的经济效益，而且填补了我国对啮虫目昆虫研究的空白，具有一定的学术价值。此文就书虱的种类、生物学特性及其防治作一概述。     

A NECESSARY AND SUFFICIENT CONDITION ON HEREDITARY HELLY HYPERGRAPHS AND CONFORMAL HYPERGRAPHS AND THEIR EQUIVALENCE

We show in this paper, a necessary and sufficient condition on hereditary K-Helly hypergraphs and conformal hypergraphs and their equivalence.     

GIS支持下的区域中低产耕地评价与改良利用对策

借助GIS和数学模型集成技术,评价荔城区中低产耕地及其障碍因素,结果表明全区中、低产耕地面积分别为2293.39公顷和1594.97公顷, 分别占保护区耕地总面积的25.49%和17.72%; 中产耕地主要分布于北高和新度镇,而低产耕地则主要分布于北高镇; 中产耕地主要限制因素为旱限制、缺钙限制、瘠瘦限制、缺钾限制、缺磷限制和酸限制,分别占中产耕地总面积的88.76％、18.26％、15.48％、8.18％、7.91％和6.53％,低产耕地主要限制因素为旱限制、缺钙限制、瘠瘦限制、障碍层限制、渍涝限制、盐碱限制和酸限制,分别占低产耕地总面积的96.98％、58.31％、54.89％、18.90％、18.47％、18.47％和16.28%。在中低产耕地及其障碍因素评价的基础上,提出了区域中低产耕地的改良利用对策。     

甜菜大、小孢子发生与雌、雄配子体发育

本文描述甜菜(Beta vulgaris L.)大、小孢子发生及其雌、雄配子体的发育,主要结论是:1.小孢子母细胞减数分裂过程中的胞质分裂为同时型。四分孢子为四面体形。2.单核小孢子分裂为营养细胞和生殖细胞时,分裂中期的纺锤体不对称,营养核的形成稍早于生殖核。分裂末期,营养细胞与生殖细胞之间有细胞壁,而后消失。生殖细胞进一步分裂形成2个精子。成熟的花粉粒为3细胞型,营养核有解体的趋势。3.花药壁由五层结构组成:最外层为表皮,其次为药室内壁,其中层包括两层细胞,绒毡层为分泌型。4.甜菜为单子房、单胚珠、双珠被、厚珠心,曲生型胚珠。大孢子母细胞经减数分裂形成线形排列的四个大孢子。合点端大孢子具功能。5.胚囊发育属于蓼型。开花前,两极核已融合为次生核。成熟胚囊由7细胞组成。具有盲囊结构。6.同一朵花中,在前期、雄蕊的发育早于雌蕊的发育;在后期,当花粉粒成熟时,雌配子体也达到成熟,雌、雄蕊发育趋于同步。     

中外稻米安全卫生标准的比较与稻米的清洁生产

稻米的安全卫生品质越来越引起人们的关注。从中外稻米安全卫生标准的比较，表明我国稻米安全卫生标准与发达国家存在很大差距。实行稻米清洁生产是提高稻米安全卫生品质和竞争力的重要途径。