QTZ40塔式起重机总体及起升机构的设计【CAD】
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QTZ40塔式起重机总体及起升机构的设计【CAD】,QTZ40,塔式起重机,总体,机构,设计,CAD
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邵阳学院毕业设计(论文)The reasonable of the bridge type derrick chooses to usePeking rises heavy conveyance machine graduate school Xu leiAbstract : Rationally selecting cranes are essential to efficiently using them. This paper presents the principles and methods for selection of overhead travelling cranes , including the selection of basic parameters , construction types and operating conditionsKey words : Overhead travelling crane Selection Principle MethodAlong with modern industrial and quick develop to extend with the production scale, the material transports the expenses is more and more high in the comparison in the production cost.Therefore how right choose to use the derrick reasonably, to increase rate of production, develop the valid function of the derrick well, satisfy the usage requests, lowering the usage cost, increasing economic performance, insure the movement the safety to all have the very important meaning.1 The choice of the basic parameter The main function in derrick in token in basic parameter characteristic of the derrick with homework ability, is a basic basis that derrick exactitude choose to use.The basic parameter of the bridge type derrick includes to rise weight, rises to go up a Class and work speed with across an etc.1.1 Rise weightAllows to rises once when derrick is normal to work the biggest quantity that mourn call the sum settles to rise weight.Mourn the sum that hook the derrick settles to rise the weight does not include to mourn the hook with move pulley set of self-respect.Grasp the cape to account into with the quantity that electromagnetism sucker wait to take the thing the device the sum settles to rise weight inside.Press standard to rule, the bridge type derrick rises what weight series adopt is a R10 to have the initiative the few department, starting from the 312 ts, pressing 1125 ratios pass to increase to 4,5,613,8,10,1215,16,20,25,32,40,50 t.But the current local bridge type derrick product just is tradition according to the production of many years, win election from the above few row a the part constitutes to rises physically weight series.The most in common use series is 5 ts,10 ts,16 ts,20 ts,32 ts with 50 ts.Usually, be to rise weight over 10 t the hour establishes two rises to rise the organization, then the lord rises to rise the organization with vice- Rises to rise the organization, two rise the ratio of the weight roughly 1 4.The lord rises to rise the organization rises the weight is big, rises to mourn heavy goods in order to; vice- rises to rise the organization rises the weight is small, but speed than quick, rises to hang lighter goods or make to lend support to the sex work in order to, to increase the work efficiency.General at the request of mays meet biggest to rises to mourn the heavy thing to make sure to rise with the derrick weight, consider at the same time the term or craft process that turn carry the work of.The derrick disallows to overload the usage, the so that is rises to mourn the thing to usually take place the situation of the variety, the derrick should consider the certain amount of .Under some circumstances, occasionally needs to mourn to carry excess article, can use two pedestal derricks be in conjunction with the homework.Fix in the craft process, rises to mourn the thing weight basic constant, derrick the circumstance that basic capacity load use next, can cancel the vice- rising rise the organization, toing simplify the construction of the derrick, declining low cost.The big tonnage bridge type derrick of the abroad too and is not all take what vice- rising rise the organization, but choose to pack according to the demand.1.2 Rises to rise the high degreeRises to go up a the distance of lead for ising to points from ground to taking the thing equips the tallest rising rises the position.If take the thing equip to need the whereabouts goes to ground below homework, from ground to take the thing the device the lowest descending put the distance of lead of the position calls the bottom puts the depth.At this time the gross rises to go up a the degree is a ground to rises to go up above a the degree puts the depth it down below with the ground with.Rise the choice that rise press homework request highly but settle.The in general use bridge type risesThe heavy machine will rise to go up generally the degree limits in the 20 ms including.Because over a boundary for then wanting in rises to rise the organization special steel wire in adoption rope involution method or enlarging a size, making rising heavy small car arranging appearing difficulty, and enlarging derrick size.Request to the car homework that pack the derrick, in made sure rose went up first degree, should still consider to go together with to belong to of hanged high degree that had with the vehicle, then guarantee derrick can pack the biggest and high product into the car.The ships that used for the derrick pack to unload and should consider the influence that tidewater rise falls.1.3 Work ClassThe place that bridge type derrick install is similar to the term difference of the usage is very big, rose the exploitation degree of the heavy ability with worked the frequency is each not.Use the derrick reasonably for the sake of the economy, need to choose the fit work Class according to the work term of the derrick.The work Class of the bridge type derrick is divided into the A1 A8 totally 8 classeseseseses, can according to the exploitation grade of the derrick with carry the the appearance of carries the the the carries the carries, namely according to the busy degree in usage of the derrick with load down the degree pass calculation is certain.The derrick counts circularly in the period in valid life span total work having certainly.A work circulation of the derrick homework is from prepares to rise to mourn the product start, arriving a whole homework for rises to mourn the product process.The work circulates to amount the exploitation degree of the token derrick.For easy to compute, will work the circulation amount to be divided into 10 exploitations grade within the scope of its possible, seeing the table 1.The load appearance enunciation derrick that carry the importance degree suffers to carry.Carrying the appearance of load has something to do with two factors: A function for is physically rising rising carrying load Qi and sum settling carrying load Qmax it ratio, another is physically rising rising carrying load Qi number of times Ni circulates with work the ratio that amount the N.The name carries the coefficient of load is divided into 4 classeseses, see the table 2, the derrick carries load coefficient KQ can press type calculation:Table 1 the exploitation grade of the derrickMake use of the gradeWorking the circulation amountsUsage circumstanceU01.6 104Dont usually useU13.2 104U26.3 104U31.25 105U42.5 105Usually light free usageU55 105Usually break to use continuouslyU61 106Not usually busy usageU72 106Busy usageU84 106U9 4 106According to KQ that compute the income, the name that can check from the table a carries the coefficient of load .Table 2 derrick names carry the coefficient of load.Carry the appearance of loadThe name carries the load coefficient KQMake use the feeling circumstanceThe Q1 is light01125Seldom rises to hang the sum settle to carry the load ,Rises to hang the light carrying the load generallyQ2 inside0125Sometimes rises to hang the sum settle to carry the load,Rises to mourn generally inside etc. Carry the loadThe Q3 is heavy015Usually rises to hang the sum settle to carry the load,Rises to hang the more heavy carrying the load generallyQ4 with heavy110It is multifarious to rises to hang the sum settles to carry the loadMade sure the exploitation grade of the derrick with carry the load appearance hereafter, can press table 3 the work Class of certain derricks.Table 3 derrick work ClassCarry the loadAppearanceThe name carries the load coefficient KQMake use of the gradeU0U1U2U3U4U5U6U7U8U9The Q1 is light01125A1A2A3A4A5A6A7A8Q2 inside0125A1A2A3A4A5A6A7A8The Q3 is heavy015A1A2A3A4A5A6A7A8Q4 with heavy110A2A3A4A5A6A7A8The in common use work in derrick in type in bridge Class also can according to the table 4 choose Table 4 bridge type derrick work Classes choose to use the for instanceDerrick useWork termWork ClassThe electricity stands, the car drives to rise with the manpower machineLight free in usageA1The electricity stands to use the derrickLight free in usageA1 A3Maintain to use the derrickThe usage is little, the usually light burthen usesA1 A3Car and warehouses use the derrickUsually break to use continuouslyA3Car and warehouses use the derrickBusy usageA4 A5The heavy work car uses the derrickHeavy usageA6Goods field、Anticipate field Use the derrickGrasp grap or electromagnetism sucker type, busy usagesA6The metallurgy factory cast, clips the derrick of pincersThe usage is multifarious and load down the usageA7The metallurgy factory takes off tablet, add to anticipate the derrickThe usage is multifarious and heavy to carry the usageA81.4 The work is flat-outThe work speed of the bridge type derrick includes to rise to rise the speed, the small car circulates the speed circulates the speed with big car.The flat-out choice in work is decided by various factors.Have something to do with rising weight first, inside, small rise the derrick of the weight choose to use the high speed to increase rate of production, big rise the derrick of the weight is proper to choose to use the low speed the since low driving the power, the steady that increase to circulate with safety.The work speed still is decided by the work Class to request with the usage, working the Class is high and usually use, request the high derrick in rate of production chooses to use the high speed; the work Class is low and used for the work organization eligibility that adjustment circulate uses the low speed; used for only the equipments install to is in addition to choosing to use the low speed with the derrick that maintain, can also according to demand, adopt double soon( quick, slow soon), tiny soon or adjust soon.The adoption changes the frequence adjust to can be made soon work speed at 1 a regulates arbitrarily.Work the speed return to have something to do with the service space size of the derrick, circulating the road grow, rises to go up a big and proper choose to use the high speed.When the derrick circulates the road shorter, the not proper adoption is super-speed, the in order to prevent dids not start to complete and then start the system moves.But along with modern industrial development, do large quantity turn the derrick that carry the work to adopt gradually the super-speed a derrick for, installing maintaining using large quantity adoption adjusts soon.To the derrick of the some special function, if used for the derrick of the work a fire homework, should have the fleetness descent device; big rises to rise the high derrick in addition to should appropriately increasing rises to rise speed, it is also heavy to carry to adopt the low speed and get empty to carry the adoption high speed, or adopt the measure acquire the higher descent the speed, with increase rate of production.1.5 Across degreeThe level distance of the big car in derrick in type in bridge movement orbit center line calls to across degree.The derrick acrosses a width for being decided by the service space primarily, useding for the derrick in the factory premises across a width for being decided by the building.For making across a degree the parameter series turns, bridge type derrick of in common use across the degree is each to a the class, the concrete number sees the table 5.Rise weight a derrick for below to should each factory premises across a hoist for having the two kinds of acrossing a value, in the factory premises above beam to stay the circumstance of the safe passage up to use the small value down.Such as at there is an on same orbit above of derrick, also there is a derrick for below, the derrick acrosses a rises for by the an above heavy machine chooses ?When same across the inside has two layer derrick, the number inside the watch is applicable to the upper level derrick only, the bottom layer derrick acrosses a value in response to for integral times of the 015 ms.When across the degree not agree with to match the form inside a row number hour belong to the special design derrick generally.Table 5 bridge type derricks across a series The factory premises acrosses degree9121518212427303336The derrick acrosses degreeRise weight3The 50 ts of 7.510.513.516.519.522.525.528.531.571013161922252831Rise weight80-250 161922252831342 The choice of the structure formFit bridge in choice, rise heavy small car, manipulate the way with take the thing equips the etc., can make bridge type derrick under every kind of particular gearing size with the homework method satisfied the usage the request betterly.2.1 BridgeThe bridge is a metals construction loading corpus.The bridge of the bridge type derrick contain single beam bridge with 2 typeses: a beam bridge, from a root or two main beams with locate to across an one for each of both sides carry the beam constitutes.While rising the weight a circumstance for below, work Class lowerly, acrossing aly smallerly, circulating the speed request to be not high, the derrick is not multifarious to use, the general eligibility uses single beam bridge.This kind of single beam derrick usually adopts the electricity moves the bottle gourd conduct and actions rises to rise the organization, for this reason construction tightly packed, self-respect and light, the price is too lower.Under the other circumstance the eligibility chooses a beam bridge, the stability likes, suffering the dint term like, circulating the function too better.For satisfying the structural request in building in particular factory premises, the form of the bridge can adopt the homologous variety.General circumstance next, main beam with carry the way that beam adopt level conjunction, manufacturing simple, adjust convenience, see figure 1 a.Sometimes the factory premises constructs the construction already certain, for satisfying to rise weight with rises to go up a request, while rising the extremely high circumstance in heavy small car, can adopt the main beam descend the cave form, seeing figure 1 b.Sometimes for the sake of high degree that lower the factory premises hoist beam, alleviate to the best the factory premises construct the construction weight, canning adopt the main beam with carry the beam do not wait the high conjunction method, seeing figure a 1 d.2.2 Rise heavy small carFigure 1 main beam with conjunction method that carry the beamRise heavy small vehicle-use come to realizes the rise and fall that rises mourn the thing with along bridge a work for of movement, its function directly affecting whole pedestal derrick function.On the general adoption in derrick in type in bridge in a beam the place type rises heavy small car, loading the ability is big, circulating steady, but the shape size is big.This kind of rises the heavy small car top arranges the electric motor and decelerate generally the machine, book constitutes of rising and rising organization.For lowering the building the high degree, the alleviation holds with dignity, simplifying the construction, canning adopt the electricity move bottle gourd the conduct and actions rises to rise the organization.The electricity moves whole machine of the bottle gourd bridge type derrick hold with dignity to lighter than the former 30% or so, the more suitable for factory premises construct to the high degree and a circumstance for pressing limit settling, now abroad already large quantity uses.The single beam derrick usually adopts the electricity moves the bottle gourd conduct and actions rises to rise to circulate the organization with the small car, and hang the lower part in single beam.This kind of construction is more agile, self-respect and lighter.But the bottle gourd descends to place and would affect to rise to go up degree.Sometimes construct the high degree in the factory premises low, but want again to increases to rise to rise possibly the high circumstance descend, the eligibility uses the low building high degree gives or get an electric shock to move the single beam in bottle gourd derrick.This kind of derrick moves the bottle gourd to the electricity to settle the flank in single beam, attaining the increment rises to rise the high purpose.This kind of derrick need to be taken extreme measure, moving to the hang type electricity the bottle gourd need the increment goes together with the heavy toing hold the balance, but also increased to hold with dignity; small car in another adoption side hang type, also can make use of the space effectively, but the small car construction sophisticates, will return to the main beam the affixture a twists the T .2.3 Manipulate the wayAdopting rises weight big, work Class high, circulate flat-out and quick derrick, very much the driver room manipulates the way, toing insure the movement the safety.The driver room usually all fixs in bridge a side of.If the derrick acrosses a very big, under the situation of rises to mourn the homework complicacy, can choose to use the driver room with rise form that heavy small car exercise together.Sometimes return the eligibility use the driver room can is ambulatory along the main beam as ones pleases of form, operate more convenient.Circulate the speed in the derrick slow, the route of travel is short, the work is not busy, and request the driver to hang, take off the circumstance of the hook directly; in the factory premises low and short or the ground equipments is high, cant install the circumstance of the driver room; have the harmful air in the factory premises upper part, cant can adopt under the situation of derrick ascending manipulating the ground manipulate.The ground manipulates the movement speed of the derrick generally not over 45 ms/ min.The ground manipulates the hand electricity door is fixed, the hand gives or get an electric shock the door moves with the small car, the hand gives or get an electric shock the door moves a few methods as ones pleases, can choose to use according to the demand.Because the adoption ground manipulates have the electric cable connect with each other, operating must follow behind the derrick exercises, therefore can also adopt the lead-in control from a distance to manipulate the way, including red and outside light or wirelesses control from a distance, making derrick manipulated more vivid convenient.This kind of manipulate the way to have got the extensive adoption abroad.2.4 Taking the thing equipsThe choice takes the thing device fitly, producing to the safety with increases to produce the efficiency have the important meaning.Because the bridge type derrick packs the object category that unload the product numerous, have results to show a piece, spread a grain with the etc. of the liquid, their physics function with several why each of shape is characteristic.Pack to unload the work for the sake of orientation various product, take in common usely the thing equip to mourn the hook, grasp the cape , electromagnetism sucker, ring and tie to have, clip the pincers , vacuum sucker and anticipate the cape , prosperous bucket with accept heavy beam etc., still gathering to pack in addition the appropriation hang to have with the other appropriation tool.Mourning the hook is a bridge type derrick application to take the thing device most extensively.Grasp the cape to be used to pack to unload to spread a material a flood ofly primarily, and also the avail grabs at the circle wood grasps the cape .Grasping the cape is a kind of taking the thing device automatically, it grasp to anticipate with unload to anticipate the action to manipulate in the driver room from the driver, doing not need to lend support to the personnel help, increasing to pack to unload the rate of production consumedly.The electromagnetism sucker is applicable to the following black metals for mourning carries have magnetic metals material of lead, generally only used for absorb 500 s.At mourn to carry the material usually changes, and the rate of production requests the higher situation, the eligibility chooses two use the bridge type derrick, take the thing device is to grasps the cape with the electromagnetism sucker, or grasp the cape with mourn the hook, or electromagnetism sucker with mourn the hook.Rising the heavy small car ascends to have two sets of each has risen since independently organization, drive to take the thing device respectively.But two take the thing device cant work at the same time.At mourn to carry the material usually change, but the rate of production requests the not very high and special situation, the eligibility chooses three use the bridge type derrick, hook the bridge type derrick at the foundation top that mourn according to the demand can at mourn to hook up the set hang the electricity moves to grasp cape or electromagnetism suckers.3 Circulate the choice of the function For making bridge type derrick under the special environment term or under the particular work satisfy the usage requests, can put forward the special request to the movement function of the derrick, including the environment request and control automatically to protect request etc. with the safety.3.1 Environment requestThe bridge type derrick is general s ses ses at-25s+40 temperature scopes inside can normal homework, be to outrun the above scope the hour need to be taken extreme measure, while making choice of purchase derrick want to put forward the special request.Under the low temperature environment the derrick of the usage needs to choose the heat preservation driver room, the metals construction should is low and pound at the higher material in tenacity manufacturing from the low temperature sensitivity.In the heat circumstance, and the porterage is red hot or melt the derrick of the metals of melt , radiates for the heat that avoid to the main beam, the main beam lower cover plank is even the stomach plank should equip the hot layer in impede , equiping to the electricity should have the adequacy reduce the heat the measure.The bridge type derrick that use in the outdoors should defend the rain measure.Rising the heavy small car, heavy car movement organization, electricity device should add to defend the rain cover.Under many powders dust circumstance the derrick of the usage, should choose to have the sexual electricity room of seal completely, the electric appliances device should have the dust palliative function.The derrick used in had easy burn easily explode admixture air environment should choose the flameproof type of.Can is divided into the different and flameproof grade with the tallest surface temperature according to the flameproof type, usage environment, Bang air mixture characteristic.The electric motor of the derrick controls the device to need to adopt with electricity what impede explodes the type, each organization spreads to move inside may because the friction has fever the place that produce the spark to also want to adopt the homologous prevention measure, the work of the derrick is flat- out to also want the cowgirl lowers, toing insure the usage the safety.Work in the bridge type derrick of the aluminum, magnesium.etc. Electrolysis smelt car an usage, because of at complete add anticipate, replace electrode and mourn carried electrolyte, hanged had at electrolysis pond that had strong and big electric current, request the relevant part of the derrick must insulate, insuring the Human body and the safety of the equipments.The so that should choose to establish x-rated insulating the derrick of the measure, then mourn the hook insulates with steel wire rope; rises to rise the organization insulate with small car a; the small car insulates with fold a.The each class insulates electric resistance must over and above a .Sometimes in metallurgy, petroleum, chemical engineering, port and heats handle the derrick of the car an usage, because of worked at corrosion that had environment lay quality, will result in to the metals construction of the derrick to decay seriously, endanger the safety of the derrick.The so that should choose the derrick that tools and implements have antisepsis ability, its metals material eligibility chooses to bear the eclipse steel, or the valid antisepsis in adoption draws the layer.When the construction designs with the technological design should consider the corrosive influence, can also adopt to sacrifice the anode the protection the method to attain the antisepsis purpose.3.2 Automatic controlAutomate the degree along with the production to increases continuously, bridge type derrick because of canning make use of the space well, having been used to the space in porterage robot move, becoming the key equipments that material transport one of the automations.The renewal of the derrick with develop, be decided by to a large extent the auto control to spread with electricity the dynamic improvement.The expert of the abroad estimates, aftertime 20% 30% bridge type derrick demand installs the automation.Grab at the goods function to the auto that have the bridge type derrick, for the sake of can by the square cargo handing, the exaltation produces the efficiency, preventing to hang to have the move but cant position effectively, should choose to defend to shake generally the function hang to have.Hang to have to defend to shake the machine type, liquid press type, electronics type, rigid lead the pole type wait various forms, the abroad still developped the control technique of the misty logic electric circuit, attaining to defend to shake the control best.In the some and special situation, if mourn to carry the fuel of nut, install precise spare part etc., request bridge type derrick can accurate fixed position.While choosing this type of derrick, at the request of put forward to position the accuracy.Demand, can also install the calculator in the driver indoors, hold the act automatic indicate that sits the punctuation, combine the automation process of proceeding every kind of porterage homework control.Use the bridge type derrick of the situation to the some importance, is safe for usage that insure the derrick, the eligibility transports an appearance and breaks down to supervise and control the system from the diagnosis.That system can at compute on board automatic manifestation big and parts of normal regulationses maintenance check contents, if the derrick carries the load , should dint with vibrate the circumstance, the important electricity a temperature for of work condition, electric motor rises, the system moves the machine rubs a work for of wear and tear condition, steel wire rope, book, pulley condition etc.3.3 The safety protectsFor the sake of guarantee derrick circulate much more safety dependable, should choose the some according to the different circumstance the safety protect the device.For example increase to the derrick that easy occurrence overload super carry restrict machine; same across the inside or top and bottom two layers have many the derrick of the multifarious homework in pedestal should equip to defend the device of collision, the derrick that outdoors usage should increase to establish to defend the slippery device in anti- in breeze; to heavy carry to wear away with steel wire rope excessively with the in bar of car wheel in derrick of the multifarious usage, can increase to establish the auto the anointment equips; to strong across a derrick can increase to establish to defend to runBe partial to device etc.The some important situation mourns the derrick that carries the dangerous goods in order to, if the nut gives or get an electric shock wreath form derrick etc. That stands, its rises to rise the organization can adopt the single item breaks down the protection, then rises to rise the organization have two suits place, being an among those appear the breakdown, the another can undertake automatically all work, mourning fair and softly the danger carry the load .This type of derrick according to demand return the eligibility chooses the some special safety equips, if decelerate only for, trouble, super route of travel limit, break fire limit, defend the steel wire rope rounds only for, equilibrium beam limit, exceed the speed limit the protection and meet an emergency to move operation equip, defend the earthquake equips etc.For making derrick is in whole usage period can the fixed amount guarantee the usefulness of the function, little out the breakdown, insure derrick great majority time to all be placed in normal revolve work appearance, while buying derrick, at the request of put forward the dependable.The current in common use and dependable index sign has: the average have no breakdown work time for the very first time; the equivalent average have no breakdown work time; the average repairs time; the usage can use an etc.4 The choice of the other aspectAt choose to use the bridge type derrick, in addition to above, have some the essential to have that factor is also a request, color of, for example the request of the driver room, hold with dignity with price etc.4.1 Driver roomFor the sake of work efficiency that exaltation driver, satisfy the labor protect the request, attaining the person match with with the coordination of the derrick, developping the effect of the derrick well, shoulding choose the driver room of the suitable for use.Should guarantee first driver contain good visual field, should still consider to guarantee the good work environment in driver.Manipulating the device should arrange the reasonable, the operation is convenient.For alleviating because of the normal operation that a vibration affect the driver, eligibility tools and implements contain driver room that the flaps the device.To driver indoors manifestation gauge with color, marking that signal equip, the gauge is most the baby size, and well ventilated, the temperature, lighting degree is even tool box etc. is at the request of put forward to match the human body engineering learn clear and definite.4.2 Color The research expresses, the color that derrick moderate can be made operation feel the spirit pleased, is beneficial to the decrease mistake, increase work efficiency.Therefore value the color of the derrick request, making it moderated with surroundings environment mutually, again more outstanding with refreshing, guarantee the movement the safety.When the concrete color designs should still synthesize the consideration well balanced and stabilize and unify with change, keynote and decorate etc. every kind of factor.4.3 Self-respect The bridge type derrick that there is equal batch quantity is between each general car to use with the warehouse of, work and not quite and heavy.In consideration of synthesize the performance, the derrick should lower the shape the high degree to the best, simplification construction, alleviate self-respect with a movement for pressing, in order to making whole building highly descending, constructing construction lightly turning, lowering building price, also can letting up derrick power, as a result can choose morely to move the bottle gourd bridge type derrick with light bridge type derrick or electricities.4.4 Price The price is an one of the important factors to choose the derrick.This price of own derrick that is not only whole life span period cost, should still consider the derrick.Since include the derrick cost, still include to use the cost, such as circulate the expenses, maintain the expenses and have the article spare parts expenses, even still consider because the derrick breaks down to shut down the influence produces but result in direct to lose with indirectly, to proceed to synthesize the performance analyze, toing pursue the best function price ratio.The function, function of the for this reason derrick want with dependable too an importance that be used as the price constitutes the part.译文：桥式起重机的合理选用北京起重运输机械研究所须雷 摘要: 起重机的合理选择是有效使用的基础。根据起重机的特点和发展趋势, 从基本参数、构造形式、运行性能等方面介绍了桥式起重机的合理选用原则与方法。关键词: 桥式起重机选用原则方法随着现代工业的迅速发展和生产规模的扩大,物料搬运费用在生产成本中的比例越来越高。因此如何正确合理地选用起重机, 对提高生产率, 充分发挥起重机的有效功能, 满足使用要求, 降低使用成本, 提高经济效益, 确保运行安全都具有十分重要的意义。1 基本参数的选择 起重机的基本参数表征起重机主要性能特征和作业能力, 是起重机正确选用的基本依据。桥式起重机的基本参数包括起重量、起升高度、工作级别、工作速度和跨度等。1.1 起重量起重机正常工作时允许一次起吊的最大质量称为额定起重量。吊钩起重机的额定起重量不包括吊钩和动滑轮组的自重。抓斗和电磁吸盘等取物装置的质量计入额定起重量内。按标准规定, 桥式起重机的起重量系列采用的是R10 优先数系, 从312 t开始, 按1125 公比递增为4 , 5 , 613 , 8 , 10 ,1215 , 16 , 20 , 25 , 32 , 40 , 50 t 。但目前国内的桥式起重机产品只是根据多年的生产惯例, 从上述数列中选出一部分组成实际的起重量系列。最为常用的系列是5 t , 10 t , 16 t , 20 t , 32 t 和50 t 。通常, 当起重量超过10t 时设两个起升机构, 即主起升机构和副起升机构, 二者起重量之比约为14。主起升机构的起重量大, 用以起吊重的货物;副起升机构的起重量小, 但速度较快, 用以起吊较轻的货物或作辅助性。一般应以起重机可能遇到的最大起吊重物来确定起重量, 同时考虑转载工作的条件或工艺过程的要求。起重机不允许超载使用, 因此在起吊物经常发生变化的场合, 起重机应考虑一定的裕量。在某些情况下, 偶尔需吊运超重物件时, 可用两台起重机协同作业。在工艺流程固定, 起吊物重量基本不变, 起重机基本满载使用的情况下, 可以取消副起升机构, 以简化起重机的结构, 降低成本。国外的大吨位桥式起重机也并不是都带有副起升机构的,而是按需要选装。1.2 起升高度起升高度是指从地面到取物装置最高起升位置的铅垂距离。如果取物装置需下落到地面以下作业, 从地面至取物装置最低下放位置间的铅垂距离称为下放深度。此时总起升高度为地面以上的起升高度和地面以下的下放深度之和。起升高度的选择按作业要求而定。通用桥式起重机一般将起升高度限制在20 m 以内。因为超过20 m 则要在起升机构上采用特殊的钢丝绳卷绕方式或增大卷筒尺寸, 使起重小车布置出现困难, 并增大了起重机的界限尺寸。对有装车作业要求的起重机, 在确定起升高度时, 还应考虑配属的吊具和车辆的高度, 以保证起重机能将最大高度的物品装入车内。用于船舶装卸的起重机应考虑潮水涨落的影响。1.3 工作级别桥式起重机安装的场所和使用的条件差别很大, 起重能力的利用程度和工作频率各不相同。为了经济合理地使用起重机, 需根据起重机的工作条件选择合适的工作级别。桥式起重机的工作级别分为A1A8 共8 级, 可根据起重机的利用等级和载荷状态, 即根据起重机的使用繁忙程度和满载程度通过计算确定。起重机在有效寿命期间有一定的总工作循环数。起重机作业的一个工作循环是从准备起吊物品开始, 到下一次起吊物品的整个作业过程。工作循环总数表征起重机的利用程度。为便于计算, 将工作循环总数在其可能范围内分成10 个利用等级,见表1。 载荷状态表明起重机受载的轻重程度。载荷状态与两个因素有关: 一个是实际起升载荷Qi 与额定载荷Qmax之比, 另一个是实际起升载荷Qi 的作用次数Ni 与工作循环总数N 之比。名义载荷谱系数分为4 级, 见表2 , 起重机载荷谱系数KQ 可按下式计算:式中m 为材料疲劳试验曲线的指数, 此处取m =3。表1 起重机的利用等级利用等级工作循环总数使用情况U01.6 104不经常使用U13.2 104U26.3 104U31.25 105U42.5 105经常轻闲使用U55 105经常断续使用U61 106不经常繁忙使用U72 106繁忙使用U84 106U9 4 106根据计算所得的KQ , 可从表2 中查得最接近的名义载荷谱系数。表2 起重机名义载荷谱系数载荷状态名义载荷谱系数KQ使用情况Q1 轻01125很少起吊额定载荷，一般起吊轻载荷Q2 中0125有时起吊额定载荷,一般起吊中等载荷Q3 重015经常起吊额定载荷,一般起吊较重载荷Q4 特重110频繁起吊额定载荷确定了起重机的利用等级和载荷状态以后，可按表3 确定起重机的工作级别。表3 起重机工作级别载荷状态名义载荷谱系数KQ利用等级U0U1U2U3U4U5U6U7U8U9Q1 轻01125A1A2A3A4A5A6A7A8Q2 中0125A1A2A3A4A5A6A7A8Q3 重015A1A2A3A4A5A6A7A8Q4 特重110A2A3A4A5A6A7A8桥式起重机常用的工作级别也可参照表4选取。表4 桥式起重机工作级别选用举例起重机用途工作条件工作级别电站、车间用人力驱动起机使用轻闲A1电站用起重机使用轻闲A1A3维修用起重机使用少, 经常轻负荷使用A1A3车间及仓库用起重机经常断续使用A3车间及仓库用起重机繁忙使用A4A5繁重工作车间用起重机繁重使用A6货场、料场用起重机抓斗或电磁吸盘式、繁忙使用A6冶金厂铸造、夹钳起重机使用频繁、满载使用A7冶金厂脱锭、加料起重机使用频繁、重载使用A81.4 工作速度桥式起重机的工作速度包括起升速度、小车运行速度和大车运行速度。工作速度的选择取决于多种因素。首先与起重量有关, 中、小起重量的起重机选用高速以提高生产率, 大起重量的起重机宜选用低速以降低驱动功率, 提高运行的平稳性和安全性。工作速度还取决于工作级别和使用要求, 工作级别高、经常使用、要求生产率高的起重机选用高速; 工作级别低、用于调整性运行的工作机构可选用低速; 仅用于设备安装与维修的起重机除应选用低速外, 还可根据需要, 采用双速(快、慢速) 、微速或调速。采用变频调速可使工作速度在110之间任意调节。工作速度还与起重机的服务空间大小有关, 运行路程长、起升高度大的宜选用高速。当起重机运行路程较短时, 就不宜采用高速, 以免没有起动完毕就开始制动。但随着现代工业的发展, 做大量转载工作的起重机日趋采用高速度, 安装维修用的起重机大量采用调速。对一些特殊功能的起重机, 如用于工件淬火作业的起重机, 应有快速下降装置; 大起升高度的起重机除应适当提高起升速度外, 还可重载采用低速、空载采用高速, 或者采取措施获得更高的下降速度, 以提高生产率。1.5 跨度桥式起重机大车运行轨道中心线之间的水平距离称为跨度。起重机的跨度主要取决于服务空间的宽度, 用于厂房内的起重机跨度取决于建筑物的宽度。为了使跨度参数系列化, 桥式起重机的常用跨度每隔3 m 为一级, 具体数值见表5。起重量50 t以下的起重机对应每种厂房跨度有两种跨度值, 在厂房上方的吊车梁上留有安全通道的情况下用小值。如在同一轨道上有80 t 以上的起重机, 也有50 t 以下的起重机时, 起重机的跨度按80 t 以上的起重机选取。当同一跨内有两层起重机时, 表内数值只适用于上层起重机, 下层起重机的跨度值应为015 m 的整数倍。当跨度不符合表中所列数值时一般属于特殊设计起重机。 表5 桥式起重机跨度系列 m 厂房跨度9121518212427303336起重机跨度起重量350t7.510.513.516.519.522.525.528.531.571013161922252831起重量80-250 161922252831342 构造形式的选择选择合适的桥架、起重小车、操纵方式和取物装置等,可使桥式起重机在各种特定安装尺寸和作业方式下更好地满足使用要求。2.1 桥架桥架是金属结构承载主体。桥式起重机的桥架有单梁桥架和双梁桥架两类,由一根或两根主梁和位于跨度两边的各一根端梁组成。在起重量10 t 以下,工作级别较低,跨度较小,运行速度要求不高,起重机不频繁使用的情况下,一般可选用单梁桥架。这种单梁起重机通常采用电动葫芦作为起升机构,因此结构紧
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