EFFICIENCY ANALYSIS OF DOUBLE CRANK RING-PLATE-TYPE PIN-CYCLOIDAL GEAR PLANETARY DRIVE

From the general formula for calculating the efficiency of planetary geartrains, the efficiency of the double crank ring-plate-type pin-cycloidal gear planetary drive isderived. To prove the theory, an experimental study has been conducted. The tested value of theefficiency of a sample set of the new-type drive in the experiment agrees with the calculated one.It shows that the new-type drive is of not merely high bearing capacity, but also quite highefficiency.

Mathematical Model and Geometrical Model of Double Pitch ZN-type Worm Gear Set Based on Generation Mechanism

The current researches on the tooth surface mathematical equations and the theory of gearing mainly pay attention to the ordinary type worm gear set（e.g., ZN, ZA, or ZK）. The research of forming mechanism and three-dimensional modeling method for the double pitch worm gear set is not enough. So there are some difficulties in mathematical model deducing and geometry modeling of double pitch ZN-type worm gear set based on generation mechanism. In order to establish the mathematical model and the precise geometric model of double pitch ZN-type worm gear set, the structural characteristics and generation mechanism of the double pitch ZN-type worm gear set are investigated. Mathematical model of the ZN-type worm gear set is derived based on its generation mechanism and the theory of gearing. According to the mathematical model of the worm gear set which has been developed, a geometry modeling method of the double pitch ZN-type worm and worm gear is presented. Furthermore, a geometrical precision calculate method is proposed to evaluate the geometrical quality of the double pitch worm gear set. As a result, the maximum error is less than 6′10–4 mm in magnitude, thus the model of the double pitch ZN-type worm gear set is available to meet the requirements of finite element analysis and engineering application. The derived mathematical model and the proposed geometrical modeling method are helpful to guiding the design, manufacture and contact analysis of the worm gear set.

Investigation of a Design Modification for Double Helical Gears Reducing Vibration and Noise

To reduce vibration and noise and increase transmission efficiency, a three segment method for modifying the pinion profile was proposed. Cutter surface equations were deduced by changing the shape of the cutter-edge, substituting three segment parabolas for the line. The influence of longitudinal tooth modifications on tooth surface load distributions was discussed. Transmission error minimization and uniformity of tooth surface load distribution were chosen as optimization goals and the modified parameters were obtained by applying the complex method. Finally, an experiment comparing the loaded transmission error, vibration, and noise both before and after modifications was carried out. The results indicate that the modified design is reliable.

Analysis of axial force of double circular arc helical gear hydraulic pump and design of its balancing device

In view of the axial force produced in the working process of double arc helical gear hydraulic pump,the theory of differential equation of curve and curved surface was utilized so that the calculation formula of axial force was obtained and the relationship between the axial force and structure parameters of gears was clarified.In order to balance the axial force,the pressure oil in the high pressure area was introduced into the end face of the plunger to press the plunger against the gear shaft,and the hydrostatic bearing whose type is plunger at the end of the shaft was designed.In order to verify the balance effect of axial force,the leakage owing to end clearance and volume efficiency of gear hydraulic pump before and after the balancing process was analyzed.This paper provides a new analysis idea and balance scheme for the axial force produced in the working process of the double arc helical gear hydraulic pump,which can reduce the leakage owing to end clearance caused by the axial force and improve the volume efficiency of the gear hydraulic pump.

Structure vibration characteristics of two stage double helical tooth planetary gear trains with unequally spaced planets and stars

A computational model of two stage double helical tooth planetary gear set is employed to built the lateraltorsional coupling dynamic governing equations. Base on the dynamic equation, the free vibration properties of the system with unequally spaced planets and stars are analyzed. The vibration modes are classified into three types: star mode, planet mode, and coupling mode. For each of the modes, the relation between inherent frequency and vibration amplitude is investigated in detail by the eigenvalue and mode characteristics.

EFFECT OF GEAR WIDTH AND HELIX ANGLE ON FACTOR OF DYNAMIC LOAD OF DOUBLE CIRCULAR ARC HELICAL GEARING

Based on theory of mechanical dynamics, meshing characteristic as well as thedynamic model of double circular arc helical gearing, an analysis approach and a computer programhave been developed for studying the state of dynamic load and factor of dynamic load of thegearing, the changing situation of dynamic load and dynamic load factor vs some affecting factorssuch as gear width, helix angle and accuracy grade etc are investigated. A series of conclusions areobtained: ①With the increasing in the values of gear width, the dynamic load factor appears slowdecreasing tendency in most region of gear width. ②When the accuracy grades of the gearing areimproved, the values of dynamic load factor decrease. ③The value of dynamic load factor appears adecreasing tendency with the increasing of value of helix angle at the same ratio of criticalrotational speed.

Oil Film Stiffness of Double Involute Gears Based on Thermal EHL Theory

Lubrication failure is one of the main failure forms of gear failure.Time varying meshing stiffness is an important factor affecting the dynamic behavior of gears.However,the influence of oil film stiffness is usually ignored in the research process.In this paper,according to the meshing characteristics of double involute gears,based on the non-Newtonian thermal EHL theory,a new calculation method of normal and tangential oil film stiffness for double involute gears is established by the idea of subsection method.The oil film stiffness difference between double involute gears and common involute gears is analyzed,and the influence of tooth waist order parameters,working conditions,and thermal effect on the oil film stiffness are studied.The results reveal that there are some differences between normal and tangential oil film stiffness between double involute gears and common involute gears,but there is little difference.Compared with the torque,rotation speed and initial viscosity of the lubricating oil,the tooth waist order parameters have less influence on the oil film stiffness.Thermal effect has a certain influence on normal and tangential oil film stiffness,which indicates that the influence of thermal effect on the oil film can not be ignored.This research proposes a calculation method of normal and tangential oil film stiffness suitable for double involute gears,which provides a theoretical basis for improving the stability of the transmission.

THEORETICAL INVESTIGATION ON STATE OF LOAD DISTRIBUTION AMONG CONTACT BEARINGS OF DOUBLE CIRCULAR ARC HELICAL GEARS

A dynamic analysis approcach to investigate the state of load distribution among contact bearings of double circular are belical gears is proposed and a computer program is developed for calculating the factor of iced distribution based on the theory of W-N gears. The changing situations of load distribution among contact bearings of the gears influenced by main issues are analyzed by a series of parametric studies.

Hybrid Micro-forming Processes and Quality Evaluation of Micro-double Gear

Micro-gear is an important actuating component used widely in the micro electro mechanical systems(MEMS) devices.The technologies of micro-forming and precision assembly are urgently developed to manufacture the micro-double gear with central shaft.In the paper,a novel hy-brid-forming process with two kinds of piercing method have been proposed to manufacture the micro-double gear using micro forming technology.The tests of hybrid forming process were carried out with two steps and the micro-double gear was successfully manufactured with good surface quality.The results also show that the hybrid micro-forming process with central piercing method can improve the defects of inclining shaft generated by double-ended piercing method.The quality evaluation of micro-double gear was conducted with surface roughness,micro-hardness and impact tests.The results show that the micro-double gear with good mechanical properties can meet the requirements of application for milli-machines.

Simulation Analysis on Quasistatic Characteristics of Multistage Face Gears with Double Crown Surfac

The multistage face gears are the core component of the planetary gear train,which is symmetrically meshed by multiple single-stage face gear and multiple cylindrical gears.However,it is difficult to synchronize the contact between face gears and cylindrical gear due to the tooth number differences.Thus,the interference problems between two stages and big stress concentration are obvious.The crown surface configuration technology and structure design were introduced to optimize the meshing condition.To improve the double crown design feasibility and meshing stability,it is necessary to establish a reasonable multistage face gears pair simulation model to evaluate various influence factors on the contact condition and quasi-static characteristics of multistage face gears structure.The relevant scatter plots are fitted by comparing the contact results with different crown quantities and friction coefficients to intuitively obtain the variation regularity of maximum deformation,maximum strain,maximum stress and maximum strain energy.The natural frequency and mode coefficient are also determined by modal analysis under these two conditions.All the above mentioned studies verified the contact conjugate properties of double crown surface configuration were suitable.The results can provide a foundation for structure optimization and transmission reliability of multistage face gears.

Experimental Investigation of the Deformation of Helical Gears with Double－Circular－Arc Tooth Profile Using Linear Variable Differential Transformer

A small hole of 0.9mm in diameter is drilled at the theoretical contact point of the convex tooth flank of the measured gear, and the hole leads throughout to the non-working flank. A stylus glued to the core of transformer is put into the hole, and the stylus can freely contact with the meshed concave tooth flank. The transformer is installed on the body of gear to be measured. Rotate the positioning worm slowly after loading, and locate the contact point at the hole of convex tooth flank, the displacement value measured is considered as the deformation of convex tooth. The deformations at the middle and the two ends of tooth breadth for the helical gears with double-circular-cra tooth profile whose modules are 3mm and 4mm respectively are measured in the paper.

Research on Design Method of Non-Circular Gear Pair with Double Generating Angles

In order to enhance the bearing capacity of non-circular gear pair, the non-circular gear pair with double generating angles is proposed based on the design idea of unsymmetrical gear with double pressure angles. The tooth profile is designed by generating cutting theory, the pure rolling mathematic model that the center line of unsymmetrical rack roll along non-circular pitch curve is built, the digital model of non-circular gear with double generating angles is created through the second development method of CAD software, and then the drive characteristic and tooth strength are analyzed. The results show that the design method for double generating angles non-circular gear proposed in this paper is feasible, which is significant to improve the bearing capacity of non-circular gear pair.

STUDY ON DOUBLE CIRCULAR ARC PROFILE SPIRAL BEVEL GEAR TRANSMISSION

A stepped double arc spiral bevel gear tooth profile is examined. The development ofconjugate tooth surfaee of double are profile spiral bevel gears is described. The design and man-ufacture of the cutter is also discussed. Experimental results show that these gears have high loadcarrying capacity and that they are suitable for heavily loaded transmission. It is asserted thatsuch gears have higher power-to-weight ratios, are longer-lived, and provide more reliable per-formance than ordinary spiral bevel gears.

EXPERIMENTAL STUDY ON LUBRICATION BEHAVIOR OF DOUBLE ENVELOPING HOUK GLASSWOKM GEARING

The lubrication behavior of double enveloping hourglass worm gearing is studied experimently. The effects of rotational speed of the worm and load on the formation of the fluid film between engagement tooth surfaces are investigated in detail. and working angle of this worm gearing is also analyzed. Some beneficial results are obtained。

双圆弧斜齿齿轮泵转子加工刀轨规划及仿真

针对双圆弧斜齿齿轮泵转子加工方法中存在的加工效率和精度比较低等问题,提出了利用球头铣刀在数控铣床上加工双圆弧斜齿齿轮泵转子的方法。研究目标是:根据双圆弧斜齿齿轮泵转子方程,结合空间啮合原理,建立了双圆弧斜齿轮的加工坐标系,根据各坐标系之间的转换矩阵,建立了双圆弧斜齿齿轮泵转子的齿面方程,模拟使用球头铣刀进行加工过程,计算出加工刀具中心在平面和空间轨迹,同时给出判定球头铣刀不发生干涉的最大半径的方法。利用VERICUT软件建立虚拟制造环境并进行铣齿仿真加工,验证了双圆弧斜齿齿轮泵转子齿面数控加工方法的正确性及其可行性。

安装误差对双圆弧齿轮啮合特性影响分析

为深入研究安装误差对双圆弧齿轮副啮合特性的影响,基于有限元法建立齿轮加载分析模型,研究啮合过程中单齿凸、凹齿廓的接触性能,对比分析安装误差对接触性能以及传动误差的影响规律。结果表明:啮合周期内,双圆弧齿轮的凹齿廓先接触且承担较大的法向接触力,但凸齿廓的啮入端接触应力最大,凸、凹齿面接触压力差与转矩成正比;安装误差对齿面接触性能影响较大,其中中心距误差容易引起齿轮分阶处应力集中,轴线平面的安装误差会引起齿面接触偏载,且对安装误差影响最大。

双圆弧齿廓椭圆齿轮建模与运动学仿真

为了满足齿轮变传动比运动、提高轮齿承载能力,结合齿轮啮合理论和双圆弧齿廓曲线结构参数特征,提出了一种新型双圆弧齿廓椭圆齿轮。阐述了其节曲线的设计方法,利用SolidWorks软件建立了双圆弧齿廓椭圆齿轮三维模型;使用Adams软件对双圆弧齿廓椭圆齿轮副模型进行了运动学仿真,分析了不同偏心率对双圆弧椭圆齿轮副传动比变化规律的影响,并对比理论传动比曲线,分析了仿真传动比曲线存在波动误差的影响因素;为了减小齿轮副振动脉冲,给出了偏心率适当的取值范围。本文的设计方法和分析结果对双圆弧齿廓非圆齿轮的参数化设计有理论参考价值,可为双圆弧齿廓椭圆齿轮副数控加工制造及应用提供依据。

高接低栽式差速变姿态行星轮系栽植机构设计与试验

针对目前旱地蔬菜钵苗移栽机大多适用于大株距(大于260 mm)移栽且投接苗与栽植位置作业高度差大、移栽性能不佳等问题,本文提出一种高接低栽式差速变姿态行星轮系栽植机构。根据中小株距蔬菜钵苗移栽农艺指导与机构设计要求,解析双行星架差速行星轮系栽植机构工作原理并建立其运动学理论模型;结合所提出优化目标构建目标函数,开发了基于Matlab GUI的栽植机构计算机辅助分析优化设计软件,通过人机交互方式获得1组较优的机构设计参数组合。通过三维建模与装配以及ADAMS软件虚拟仿真,初步验证了机构正确性与合理性。开展栽植机构物理样机试制与试验台架系统开发研究,通过空转试验测试,验证了栽植机构实际作业轨迹、姿态与虚拟仿真及理论设计的一致性;开展栽植机构接苗与栽植性能试验,试验结果表明,栽植机构在接苗与栽植各项试验指标均较为优秀,能够满足栽植机构预期设计要求与旱地移栽机械标准,验证了该机构的可行性与实用性。

双摆线针齿传动齿廓特性与啮合特性分析

将双摆线齿廓运用到NN型少齿差行星齿轮传动领域,通过分析内外摆线轮齿廓的凹凸性、曲率和曲率半径,获得了内、外摆线齿廓的特性;通过图解法推导双摆线针齿传动中内、外摆线轮的压力角计算公式,获得了啮合过程压力角变化规律,以及双摆线针齿主要参数对于内、外摆线轮压力角的影响;通过对等距修形和移距修形进行研究,表明齿廓修形对齿形有明显影响。

泵用微连通对称双卸荷槽及其困油与流量特性

为了充分提高外啮合齿轮泵的困油性能和完善双卸荷槽的现有设置理论,提出了一种双卸荷槽微连通对称设置的创新结构,并以常规无连通对称设置的双矩形卸荷槽为例,依次给出了创新结构的实现方法,构建了困油压力和理论流量的计算模型,比较分析了常规结构和创新结构下的困油压力、排量损失以及流量脉动质量等。结果表明:啮合点位置越接近最小困油容积位置,创新结构下的卸荷面积越大,突出解决了常规结构下该处的零卸荷面积问题;通过充分缓和常规结构下的困油压力,创新结构有效地避免了困油的高压冲击与低压气穴所造成的危害;相对于常规结构,创新结构的理论排量稍有下降,流量脉动有所加剧等。研究结果可为齿轮泵的优化设计提供参考。