Design and analysis of logarithmic spiral type sprag one-way clutch

A complete mathematical model for logarithmic spiral type sprag one-way clutch design and analysis is given.It assumes that the motion of all clutch components can be expressed by a model of epicyclic gearing.It takes advantage of Hunt-Crossley contact impact theory to calculate the contact forces between sprags and races,and it can be used for optimization of design and comparison with other types of sprag clutches.A good deal of analysis shows that the parameters of the steady windup angle,the steady contact force,the natural frequency and natural cycle of clutch have nothing to do with the initial velocity of outer race,while the parameters of the maximum transient windup angle,the maximum transient impact force and the steady engagement time increase linearly in the mode of engaging operation of clutch.It is also shown that the strut angle has great influence on the dynamic engagement performance of clutch.The parameters of the steady windup angle,the maximum transient windup angle,the steady engaging time,the steady contact force,the maximum transient impact force and the natural cycle of clutch decrease linearly nearly with the inner strut angle,while the natural frequency of the system increases linearly with the inner strut angle.

Combined-Type Continuous Variable Transmission with Quadric Crank Chains and One-Way Clutches

The conventional Continuously Variable Transmission （CVT） has been classified as belt-type or toroidal CVTs. Each CVT is fundamentally composed of several components to transmit the frictional force or torque generated by the driving force. Since the conventional CVTs use friction force, their energy （force or torque） transfer efficiency might be inferior due to slippage and pressure between the transmission components. Consequently, we propose a new type of structural CVT. The CVT we proposed in this paper means a combined-type transmission with quadric crank chains and one-way clutches.

Realization of an integrated seeding and compensating potato planter based on one-way clutch

The yield reduction caused by miss-seeding in potato mechanized sowing is astonishing.The existing research always needs to install a spare compensator on the original seed-metering device.Therefore,problems of complex planter structure and compensated potato seed poor landing accuracy need to be solved urgently.Consequently,a scheme of integrated seeding and compensating potato planter based on one-way clutch is proposed in this paper.Based on a basic‘improved one raw potato planter’and the working principle of one-way clutch,power of seed-metering system is provided through main power transmission one-way clutch by land wheels when the system works properly.However,when miss-seeding detection system with infrared radiation deciding that a miss-seeding incident has happened,the seed-metering power will be replaced by a compensatory motor through compensating one-way clutch at a higher speed.Thus,the idea of catching-up compensation can be realized.After compensation is completed,the system controller disconnects the compensatory motor,and the seed-metering power will naturally switch to the land wheels again.A prototype based on this idea was built.Field tests showed that the accuracy of seed monitoring system is more than 99.9%;the adoption of catching-up compensation scheme does not bring about empty spoon rate rise significantly.Within the range of 0.2-0.8 m/s of the seed-metering chain speed,although the average success compensation rate decreases evidently with the increase of the chain speed,the success compensation rate is still near 70%even at 0.8 m/s,the vast majority of missed seeds can be compensated effectively.

函数展开计数在CLUTCH方法中的初步应用

反复裂变几率(IFP)方法广泛应用于求解k特征值对连续能量核数据的灵敏度系数,然而IFP方法存在内存占用大的问题,因此CLUTCH方法被提出以解决该问题。但对于大规模问题,如压水堆全堆问题,基于网格的CLUTCH(CLUTCH-Mesh)方法存在权重函数不易收敛的问题。本文采用函数展开计数(FET)方法对CLUTCH方法中的权重函数进行统计(CLUTCH-FET)以解决该问题,函数展开计数选取的基函数是勒让德多项式。本文在蒙特卡罗粒子输运计算程序NECP-MCX中实现了IFP、CLUTCH-Mesh和CLUTCH-FET 3种方法,以IFP方法的计算结果作为参考解,对CLUTCH-Mesh和CLUTCH-FET方法的精度和效率进行了验证。数值结果表明:对于小规模问题,如Godiva和Flattop问题,CLUTCH-Mesh和CLUTCH-FET方法具有与IFP方法相当的精度,且计算效率较IFP方法更高;对于大规模问题,如AP1000全堆问题,CLUTCH-Mesh方法的计算精度下降,而CLUTCH-FET方法可保持较高的精度和计算效率,CLUTCH-FET方法的品质因子较IFP方法和CLUTCH-Mesh方法分别最多提高了5.2和6.0倍。

Fault Diagnosis for Buckling Friction Components in Wet Multi-Disc Clutches Using IHHT

The wet multi-disc clutches are extensively used in various transmission systems,withone of the most prevalent failure modes being the buckling deformation of friction components.Animproved Hilbert-Huang transform method(IHHT)is proposed to address the limitations of tradi-tional time-domain vibration analyses,such as low accuracy and mode mixing.This paper first clas-sifies the buckling degree of the friction components.Next,wavelet packet transform(WPT)isapplied to the vibration signals of different buckling plates to partition them into distinct fre-quency bands.Then,the instantaneous features are extracted by empirical mode decomposition(EMD)and Hilbert transform(HT)to discarding extraneous intrinsic mode function(IMF)com-ponents.Comparative analyses of Hilbert spectral entropy and time-domain features confirm theenhanced precision of IHHT under specific classifiers,which is better than traditional methods.

The clutch size,incubation behavior of Reeves’s Pheasant(Syrmaticus reevesii) and their responses to ambient temperature and precipitation

Weather conditions play a pivotal role in embryo development and parental incubation costs,potentially impacting the clutch size and incubation behavior of birds.Understanding these effects is crucial for bird conservation.Reeves’ s Pheasant(Syrmaticus reevesii) is a threatened species endemic to China,which is characterized by female-only incubation.However,there is a lack of information regarding the impact of weather conditions on clutch size and incubation behavior in this species.Using satellite tracking,we tracked 27 wild female Reeves’ s Pheasants from 2020 to 2023 in Hubei Province,China.We explored their clutch size and incubation behavior,as well as their responses to ambient temperature and precipitation.Clutch size averaged 7.75 ±1.36,had an association with average ambient temperature and average daily precipitation during the egglaying period,and was potentially linked to female breeding attempts.Throughout the incubation period,females took an average of 0.73 ±0.46 recesses every 24 h,with an average recess duration of 100.80 ±73.37 min and an average nest attendance of 92.98 ±5.27%.They showed a unimodal recess pattern in which nest departures peaked primarily between 13:00 and 16:00.Furthermore,females rarely left nests when daily precipitation was high.Recess duration and nest attendance were influenced by the interaction between daily mean ambient temperature and daily precipitation,as well as day of incubation.Additionally,there was a positive correlation between clutch size and recess duration.These results contribute valuable insights into the lifehistory features of this endangered species.

解读竞赛压力下的运动表现:一个“Clutch”视角的运动能力初探

"Clutch"是一种与"Choking"典型相反的现象,主要描述运动员在比赛关键时刻的完美表现。基于"Clutch"表现,从现象学的角度,讨论压力下运动能力的发挥,并分析"Clutch"运动员的能力表现特征,旨在为优秀运动员的训练和选拔提供理论依据。研究认为,竞赛压力下的运动表现存在极性现象,"Choking"反映的是负性运动表现,而"Clutch"反映的是正性运动表现。从特征解释上讲,"Choking"表述为情景的运动表现,而"Clutch"则是特质的运动表现。"Clutch"反映了运动员在压力下展示技术的能力,一般发生在优秀运动员身上。通过"Clutch"运动表现的案例分析,结合相关研究成果,认为"Clutch"运动员是存在的,并提出了"Clutch"运动员的能力表现解释模型。该模型主要包括"专项运动能力"、"压力认知应对能力"和"运动员人格"3个方面。

Study of Controlling Clutch Engagement for AMT Based on Fuzzy Logic

The control of the clutch engagement for an automatic mechanical transmission in the process of a tracklayer getting to start is studied. The dynamic model of power transmission and automatic clutch system is developed. Using tools of Simulink, the transient characteristics during the vehicle starting, including the jerk and the clutch slip time, are provided here. Based on the analyses of the simulation results and driver’s experiences, a fuzzy controller is designed to control the clutch engagement. Simulation results verify its value.

Dynamic Performance Simulation of Power Shift Clutch During Shift

Based on the theoretical analyses, the dynamic and mathematical models of the system were developed. The models were implemented in the ambit of the Matlab/Simulink environment, and an integrated simulation model was developed. The dynamic performance of the power shift clutch during engagement and disengagement was studied by using this assembly model. The sliding speed, torque transmitted through the clutch, and the rate at which energy is dissipated during the process were determined. Using this model, the calculation during simulation can be simplified. This lays a foundation for the dynamic performance research on the power train with the power shift clutch, and provides a powerful tool for developing an automatic, electronically controlled transmission.

Oil-Film Clutch in Soft-Start of Belt Conveyor

The oil film clutch, which is superior in speed adjustment, is capable of being used in the belt conveyor to carry out soft start operation. According to running properties of both belt conveyor and oil film clutch, equations that are used to decide the lubricating oil flow and the number of oil films (i.e. the number of rotating and stationary plates) are deduced theoretically. Also key parameters are provided for the design of the hydraulic system. All these together provide the theoretical basis for the soft start design of the belt conveyor and references for the application of the oil film clutch in similar fields.

“Clutch”运动员特征的概念构图

研究基于王进等(2013)的"Clutch"运动员能力特征假设模型,运用概念构图的数据分析方法,验证"Clutch"运动员的结构解释要素。被试为6名高级教练员、6名优秀运动员和6名运动训练方面的专家,通过一对一的深度访谈,收集数据作为分析素材。然后按照创建分析单元、分类、多维定标、聚类分析、完成概念构图和解释概念构图的顺序进行分析。结果支持了王进等的"Clutch"运动员的结构要素解释假设模型,并且发现解释模型的3个要素可具体分解为压力认知敏感度、压力应对能力、心智能力、身体与技战术能力、心理敢为性、态度积极性、心理坚韧性和自信8个维度。并进一步讨论了其概念的内涵。

Analysis of the Test of ER Fan Clutch

Aim To carry out an experiment of the application of ER fluids in the clutch by reforming a fan clutch used in a truck. Methods At three different input rotating speeds,when the strength of applied electric field was changed, the output rotating speeds were recorded and analyzed. Results By comparing the results got under different experimental procedures with those measured with an electro-rheometer, it can be seen that the shearing rate has tremendous influence on the speed modulating of a fan clutch. This is because the disperse phase can't form chains (clusters)easily at high shear rate.Conclusion The result tested on the present ER fluid demonstrates that this fluid will show the properties of Newton one,i.e. its apparent viscosity is constant. as the shear rate increases.

相对化One-Way函数的存在性

One- Way函数在计算复杂性和密码技术中均有重要的应用 .将 Grollmann和 Selman的结果推广到相对化和非一致复杂类的情形 ,证明了复杂类 UP/ poly,UP,P/ poly等之间的包含关系与强相对化 one- way函数、弱相对化 one-

离合器固定螺栓断裂原因分析

为解决市场上连续出现1204拖拉机离合器固定螺栓断裂故障,通过对1204拖拉机离合器固定螺栓断裂故障件进行详细测量、计算,发现发动机飞轮的M8螺纹孔深度与固定螺拴实际拧入超差1.06 mm,造成螺栓拧紧后存在假紧状态,离合器无法完全固定,导致离合器因受力后松动造成固定螺栓断裂。改进后螺纹孔深度由15 mm修正为21 mm,改进后未再发生类似故障,适宜推广应用。

基于离合式承压箱的复合地基静载荷检测技术

本文主要介绍了一种基于离合式承压箱的复合地基静载荷检测技术。以某厂房的水泥搅拌桩加固软土地基工程为例,随机选取20根柱分别使用常规承压板和离合式承压箱进行了复合地基静载荷检测,同时使用ABAQUS软件构建复合地基模型进行了数值模拟。采用分级加荷的方式,分别测定不同荷载下的复合地基沉降量。结果表明,基于离合式承压箱的检测结果更接近数值模拟结果,说明该检测技术具有更高的精确性。在桩土应力比方面,基于离合式承压箱的复合地基桩土应力比曲线中,桩土应力比与荷载的线性关系更好。综上,基于离合式承压箱的复合地基静载荷检测技术具有节约时间、精度更高的优势。

基于VC++的汽车离合器设计软件Clutch_CAD的开发

以Visual C++为软件开发平台,采用Access数据库为数据管理平台,对汽车离合器主要设计参数进行计算和校核分析,开发汽车离合器设计软件Clutch_CAD。用传统方法需要长时间重复计算和制图才能得到的数据和曲线,利用Clutch_CAD可以很方便地得到,这对于提高离合器设计效率、缩短新产品开发周期,特别是提高离合器工作性能都具有非常重要的意义。

Choking与Clutch运动员的自我感知、状态焦虑及应对方式质性研究——以乒乓球项目为例

压力通常被认为是影响工作的重要因素,“Choking”与“Clutch”是常见的压力极性化表现。以乒乓球项目为例,通过对运动员出现“Choking”或“Clutch”时的自我感知、状态焦虑及应对方式进行质性研究,解读两种比赛状态的表现特征及诱因,并对减少“Choking”现象的产生,增加“Clutch”的发生概率提出建议。

A new group key management scheme based on keys tree, XOR operation and one-way function

By introducing XOR operation and one-way function chains to group key management schemes based on the keys tree, a new group key management scheme based on the keys tree, XOR operation and one-way function chains is proposed. Initialization, member adding and member evicting operations are introduced. The new scheme is compared with three other group key management schemes which are based on the keys tree： SKDC, LKH, and OFF. As far as transmission, computation and storage costs are concerned, the performance of the new group key management scheme is the best. The security problem of the new scheme is analyzed. This new scheme provides backward and forward security, i.e.. newly admitted group members cannot read previous multicast messages and evicted members cannot read future multicast messages, even with collusion by many arbitrarily evicted members.

Experimental Research and Mathematical Model of Drag Torque in Single-plate Wet Clutch

Reduction of drag torque is one of important potentials to improve transmission efficiency.Existing mathematical model of drag torque was not accurate to predict the decrease after oil film shrinking because of the difficulty in modeling the flow pattern between two plates.Flow pattern was considered as laminar flow and full oil film in the gap between two plates in traditional model.Subsequent equivalent circumferential degree model presented an improvement in oil film shrinking due to centrifugal force,but was also based on full oil film in the gap,which resulted difference between model prediction and experimental data.The objective of this paper is to develop an accurate mathematical model for the above problem by using experimental verification.An experimental apparatus was set up to test drag torque of disengaged wet clutch consisting of single friction and separate plate.A high speed camera was used to record the flow pattern through transparent quartz disk plate.The visualization of flow pattern in the clearance was investigated to evaluate the characteristics of oil film shrinking.Visual test results reveal that the oil film begins to shrink from outer radius to inner radius at the stationary plate and only flows along the rotating plate after shrinking.Meanwhile,drag torque decreases sharply due to little contact area between the stationary plate and the oil.A three-dimensional Navier-Stokes （N-S） equation based on laminar flow is presented to model the drag torque.Pressure distributions in radial and circumferential directions as well as speed distributions are deduced.The model analysis reveals that the acceleration of flow in radial direction caused by centrifugal force is the key reason for the shrinking at the constant feeding flow rate.An approach to descript flow pattern was presented on the basis of visual observation.The drag torque predicted by the model agrees well with test data for non-grooved wet clutch.The proposed model enhances the precision for predicting drag torque,and lays down a framework on which some subsequent models are developed.

OPTIMAL CONTROL APPLIED IN AUTOMATIC CLUTCH ENGAGEMENTS OF VEHICLES

Start-up working condition is the key to the research of optimal engagementof automatic clutch for AMT. In order to guarantee an ideal dynamic performance of the clutchengagement, an optimal controller is designed by considering throttle angle, engine speed, gearratio, vehicle acceleration and road condition. The minimum value principle is also introduced toachieve an optimal dynamic performance of the nonlinear system compromised in friction plate wearand vehicle drive quality. The optimal trajectory of the clutch engagement can be described in theform of explicit and analytical expressions and characterized by the deterministic and accuratecontrol strategy in stead of indeterministic and soft control techniques which need thousands ofexperiments. For validation of the controller, test work is carried out for the automated clutchengagements in a commercial car with an traditional mechanical transmission, a hydraulic actuator, agroup of sensors and a portable computer system. It is shown through experiments that dynamicbehaviors of the clutch engagement operated by the optimal control are more effective and efficientthan those by fuzzy control.