本科毕业论文---饺子机及输送成型部件设计.doc

编号无锡太湖学院毕业设计（论文）相关资料题目： 饺子机及输送成型部件设计 信机 系 机械工程及自动化专业学 号： 0923015学生姓名： 指导教师： （职称：副教授 ） （职称： ）2013年5月25日目 录一、毕业设计（论文）开题报告二、毕业设计（论文）外文资料翻译及原文三、学生“毕业论文（论文）计划、进度、检查及落实表”四、实习鉴定表无锡太湖学院毕业设计（论文）开题报告题目： 饺子机及输送成型部件设计 信机 系 机械工程及自动化 专业学 号： 0923015 学生姓名： 指导教师： （职称：副教授 ） （职称： ）2012年11月25日 课题来源自拟题目科学依据（包括课题的科学意义；国内外研究概况、水平和发展趋势；应用前景等）（1）课题科学意义饺子食品机械的应用前景和发展现状 饺子食品在我国历史悠久，伴随着几千年的文明的发展已经成为我国食品文化中的代表，如饺子、包子、馄饨是主食的一部分；汤圆、月饼、粽子是传统节日中必不可缺的食物。如今，经济的迅速增长、人民生活水平的提高和生活节奏的加快，对食品行业提出了新的要求。而本人认为这些要求可以归纳为两大类： 其一是食品的质量：如食用口感、卫生状况、营养含量等。 其二便是食品供应的速度。 而解决这两个矛盾要求的办法便是实现食品生产的机械化和自动化， 通过机械动作可以极大程度的提高食品的生产率； 采用环保的机械材料和严格的密封技术可以很好的保证食品卫生；而合理的工艺编排更能改善食品的口感。（2）饺子机的研究状况及其发展前景 目前国内外厂家在包馅夹馅食品机械化上的研究已经取得了一定的成果成功研发了饺子机、包子机、馄饨机、汤圆机、月饼机以及自动化程度更高的全自动万能包馅机。 因东西方饮食文化的差异， 目前国外包馅成型类机械主要为日本所生产，如日产的自动万能包馅机，其最大生产能力可达每小时 8000 个，且加工范围极广，能生产各式馒头、包子、饺子、夹馅饼干、寿司、等等近百种产品，采用可拆卸料斗能实现快速更换馅料，内置的无级变速调控装置可以实现皮和馅的任意配比。广泛用于各种带馅食品的加工。 而国内相关机械虽然在自动化和多功能方面较之日本产品还有一定的差距， 但是通过改革开放以后二十余年的发展亦取得了很大的进步。 以上海沪信饮料食品机械有限公司生产的水饺机为例：配备 1.1Kw 的电动机，生产效率达每小时 7000 个。已相当接近日产饺子机的生产水平。每逢过年过节现做现卖饺子往往出现供不应求的现象。当然也有很多人选择在家里自己做饺子，却需要提前半天甚至一天进行准备，而包饺子的时候更是要叫上好几个亲朋过来帮忙方可。 因此如果能研究开发一种能够以机械动作代替人工劳动的机器， 那么除了可以节约大量的时间、降低饺子的生产成本、提高利润之外，更可以免除人们冬日里冒寒排队购物之苦，一举多得。饺子生产机的初步目标确定为能够实现子包馅工艺的机械化。 未来可在此基础上加以改进和扩展，以实现横纵两方向发展，即饺子生产全过程的无人干预自动化与多功能化研究内容 熟悉饺子机的工作原理与结构； 熟悉饺子机输送成型部件的布置与结构； 熟练掌握绞龙、叶片泵的设计计算方法； 掌握的使用方法。拟采取的研究方法、技术路线、实验方案及可行性分析（1）实验方案对饺子机的整体的设计，确定面料和馅料的输送方式与设备结构，确定饺子成型方式，使其能够半自动的进行加工。（2）研究方法 用进行二维画图，对饺子机结构有个全面的了解。 对饺子机的输送成型部分进行计算与结构设计，使其满足物料的输送要求，并加工出合适形状的饺子。研究计划及预期成果研究计划：2012年10月12日-2012年12月31日：按照任务书要求查阅论文相关参考资料，完成毕业设计开题报告书。2013年1月1日-2013年1月27日：学习并翻译一篇与毕业设计相关的英文材料。2013年1月28日-2013年3月3日：毕业实习。2013年3月4日-2013年3月31日：饺子机输送和成型部件设计。2013年4月1日-2013年4月14日：饺子机总体结构设计。2013年4月15日-2013年4月28日：部件图和零件图设计。2013年4月29日-2013年5月21日：毕业论文撰写和修改工作。预期成果：达到预期的毕业设计要求，设计出的饺子机可以进行半自动加工，可以快速美观的加工出饺子，并且输送稳定有效、成型简单、满足工作要求。特色或创新之处饺子机可以无需手工进行制作。 饺子制作过程安全，方便，快速，可以批量生产。已具备的条件和尚需解决的问题 设计方案思路已经明确，已经具备机械设计能力和饺子机方面的知识。 进行结构设计的能力尚需加强。指导教师意见 指导教师签名：年 月 日教研室（学科组、研究所）意见 教研室主任签名： 年 月 日系意见 主管领导签名： 年 月 日英文原文 Case StudyTheoretical and practical aspects of the wear of vane pumpsPart A. Adaptation of a model for predictive wear calculationAbstract The aim of this investigation is the development of a mathematical tool for predicting the wear behaviour of vane pumps uscd in the standard method for indicating the wcar charactcristics of hydraulic fluids according to ASTM D 2882/DIN 51389. The derivation of the corresponding mathematical algorithm is based on the description of the combined abrasive andadhesive wear phenomena occurring on the ring and vanes of the pump by the shear energy hypothesis, in connection withstochastic modelling of the contacting rough surfaces as two-dimensional isotropic random fields. Starting from a comprehensive analysis of the decisive ring-vane tribo contact, which supplies essential input data for the wear calculation, the computational method is adapted to the concrete geometrical, motional and loading conditions of thetribo system vane pump and extended by inclusion of partial elastohydrodynamic lubrication in the mathematical modej. For comparison of the calculated wear behaviour with expenmental results, a test series on a rig described in Part B was carried out. A mineral oil-based lubricant without any additives was used to exclude the influence of additives which cannot be described in the mathematical model. A good qualitative correspondence between calculation and experiment regarding the temporal wear progress and the amount of calculated wear mass was achieved.Keywords: Mathematical modelling; Simulation of wear mechanisms; Wear testing devices; Hydraulic vane pumps; Elastohydrodynamic lubrication;Surface roughness1. Introduction In this study, the preliminary results of a newmethodological approach to the development of tribo- meters for complicated tribo sysLems are presented. The basic concept involves the derivation of a mathematical algofithm for wear calculation in an interactive process with experiments, which can be used model of the tribo system to be simulated. In this way, an additional design tool to achieve the correlation of the wear rates of the model and original system is created. The investigations are performed for the Vickers vane pump V104 C usedin the standard method forindicating the wear characteristics of hydraulic fluids according to ASTM D 2882/DIN 51 389. In a first step, a mathematical theory based on the description of abrasive and adhesive wear phenomena by the shear energy hypothesis, and including stochastic modelling of the contacting rough surfaces, is adapted to the tribological reality of the vane pump, extended by aspects of partial elastohydrodynamic lubrication and verified by corresponding experiments. Part A of this study is devoted to the mathematical modelling of the wear behaviour of the vane pump and to the verification of the resulting algorithm; experimental wear investigations represent the focal point of Part B, and these are compared with the results of the computational method derived in Part A.2. Analysis of the tribo contact The Vickers vane pump V 104 C is constructed as a pump for constant volume flow per revolution. The system pressure is led to the bottom side of the 12 vanes in the rotor slots to seal the cells formed by each pair of vanes, the ring, the rotor and the bushings in the tribologically interesting line contact of the vane and inner curvature of the ring (Fig. 1). Simultaneously, all other vane sides are stressed with different and periodically alternating pressures of the fiuid. A comprehensive structure and stress analysis based on quasistatic modelling of all inertial forces acting on the pump, and considering the inner curvature of the ring, the swivel motion of the vanes in relation to the tangent of curvature and the loading assumptions, is described in Refs. 1-3. Thereby, a characteristic graph for the contact force Fe as a function of the turn angle can be obtained, which depends on the geometry of the vanes used in each run and the system pressure. From this, the inner curvature of the ring can be divided into four zones of different loading conditions in vane-ring tribo contact (Fig. 2), which is in good agreement with the wear measurements on the rings: in the area of maximum contact force (zone n), the highest linear wear could be found 2,3 (see also PartB).3. Mathematical modelling3.1. Basic relations for wear calculation The vane and ring show combined abrasive and adhesive wear phenomena (Fig. 3). The basic concepts of the theory for the predictive calculation of such wear phenomena are described in Refs. 4-6. Starting from the assumption that wear is caused by shear effects in the surface regions of contacting bodies in relative motion, the fundamental equation (1)for the linear wear intensity Ih in the stationary wear state can be derived, which contains the specific shear energy density es/ro, interpretable as a material constant, and the real areaArs of the asperity contacts undergoing shear. To determine this real contact area, the de- scription of the contacting rough surfaces as two-dimensional isotropic gaussian fields according to Ref.7 is included in the modelling. Thus the implicit functional relationwith the weight function (2)is found, which can be used to calculate the surface ratio in Eq. (1) for unlubricated contacts from the hertzian pressure Pa acting in the investigated tribo contact by a complicated iterative process described in Refs. 6,8. The concrete structure of the functions F and c depends on the relative motion of the contacting bodies (sliding, rolling). The parameter a-（m0m4）/m22represents the properties of the rough surface by its spectral moments, which can be deter- mined statistically from surface profilometry, and the plasticity index妒= (mOm4)y4(E/H) is a measure of the ratio of elastic and plastic microcontacts.3.2. Extension to lubricated contacts The algorithm resulting from the basic relations for wear calculation was applied successfully to unlubricated tribo systems 8. The first concepts for involving lubrication in the mathematical model are developed in Ref. 8. They are based on the application of the classical theory of elastohydrodynamic lubrication (EHL) to the microcontacts of the asperities, neglecting the fact that there is also a macrolubrication film which separates the contacting bodies and is interrupted in the case of partial lubrication by the asperity microcontacts. Therefore their use for calculating practical wear problems leads to unsatisfactory results 9. They are extended here by including the following assump- tions in the mathematical model.(1) Lubrication causes the separation of contacting bodies by a macrofilm with a mean thickness u. which can be expressed in terms of the surface roughness by 10 (3)Where u0 is the mean film thinkness according to classical EHL theory between two ideally smooth bodies, which can be determined for line contact of the vane and ring by11(2) In the case of partial lubrication, the macrofilm is interrupted during asperity contacts. A plastic microcontact is interpreted as a pure solid state contact, whereas for an elastic contact the roughness is superimposed by a microlubrication film. Because of the modelling of the asperities as spherical indenters, the microfilm thickness can be determined using the EHL theory for sphere-plane contacts, which is represented in the random model by the sliding number 8 (5)(3) The hertzian pressure acting in the macrocontact works in two parts: as a hydrodynamic pressure pEH borne by the macrolubrication film and as a pressure pFK borne by the roughness in solid body contact.(4) For pure solid state contacts, it is assumed that the limit for the mean real pressure prFK which an asperity can resist without plastic deformation can be estimated by one-fifth to one-sixth of its hardness (6)Investigations on the contact stiffness in Ref. 11 have led to the conclusion that the elastic properties of the lubrication film cause a relief of the asperities, which means that the real pressure working on the asperity is damped. Therefore, in the mathematical model for lubricated tribo systems, an additional term fffin, which corrects the upper limit of the real pressure as a functionof the film thickness, is introduced p,EH =prFK1 -fcorr(U) (7)This formula can be used to determine a modified plasticity index PEH for lubricated contacts according to Ref. 8. Altogether, the basic model for wear calculation can be extended for lubricated tribo systems by replacing relation (2) by (8)(3)3.3. Adaptation to the tribosystem vane pump To apply the mathematical model for wear calculation to a concrete tribo system, all material data (specific material and fluid properties, roughness parameters) used by the algorithm must be determined (see Part B). Moreover, the model must be adapted to the mechanical conditions of the wear process investigated. On the one hand, this is related to the relative motion of the bodies in tribo contact, which influences the concrete structure of function f in formulae (2) and (8). In the case of vane-ring contact, sliding with superimposed rolling due to the swivel motion of the vanes was modelled (9)A detailed derivation of the corresponding formulae for fsliding and f.olling can be found in Refs. 8,9. On the other hand, the hertzian presstire Pa acting on tribo contact during the wear process has an esseritial importance in the wear calculation. For the tribo system vane pump, the mean contact force Fe in each loading zone can be regarded as constant, whereas the hertzianpressure decreases with time. The reason for this is the wear debris on the vane, which causes a change n the vane tip shape with time,leading to an increased contact radius and, accordingly, a larger contact area To describe this phenomenon by the mathematical wear model, the volume removal Wvl of one vane in terms of the respective contact radius Ri(t) at time t and the sliding distance SR(Rl(t is given by (10)where the constants a and b can be determined by regression from the geometrical data of the tested vanes. The corresponding sliding distance necessary to reach a certain radius Ri due to vane wear can be expressed using the basic equation (1): (11)Thus, applying Eq. (11) together with Eq. (10) to the relation (12)it is possible to derive the following differential equation for the respective volume removal Wvll of the ring, which can be solved by a numerical procedure (13) The required wear intensities of the vane and ring can be calculated by Eq. (8) as a function of the contact radius from the hertzian pressures working in each loading zone, which are available from the contact force by the well-known hertzian formulae.3.4 Possibilities of verification If all input data are available for a concrete vane pump run (the concrete geometrical, material and mechanical conditions in the cartridge used and the specific fluid properties, see Part B), the mathematical model for the calculation of the wear of vane pumps derived above can describe quantitatively the following relations.(1) The sliding distance SR(RI) and, if the number of revolutions of the pump and the size of the inner ring surface are known, the respective run time t of the pump which is necessary to reach a certain shape of the vane tips due to wear.(2) The volume removal W,.:uri(t) and the wear masses WmW(t) of the vane and ring as a function of the run time t.(3) The mean local linear wear Wl(t) in every loading zone on the ring at time t. Thus an immediate comparison between the calculated and experimentally established wear behaviour, with regard to the wear progress in time, the local wear progress on the ring and the wear masses at a certain time t, becomes possible.4。Results In this study, the verification of the theoretical results obtained by comparison with experiments is based on a test series on a rig according to DIN 51 389 described in detail in Part