【正文】 減速停止。 此次設(shè)計(jì)的液壓升降同步平臺(tái)是為滿足在轎車維修行業(yè)中所使用的升降平臺(tái)?？紤]到汽車如果有需要將車身整體脫離平臺(tái)而懸空的使用工況，例如檢修時(shí)需要將車輪卸下，或者需要換裝輪胎等等，都需要滿足整體車身的全部托起，為此，本次設(shè)計(jì)在兩個(gè)平板上各自設(shè)置了另一套升降裝置，以利于利用此升降裝置將汽車底 盤托起，實(shí)現(xiàn)車體的整體懸空。 可編程控制器（ PLC）是一種工業(yè)控制計(jì)算機(jī)，是繼承計(jì)算機(jī)、自動(dòng)控制技術(shù)和通信技術(shù)為一體的新型自動(dòng)裝置。 。 本設(shè)計(jì)是基于比例換向閥的液壓缸活塞桿位置控制系統(tǒng)，即利用 PLC 產(chǎn)生的控制信號(hào)驅(qū)動(dòng)電液比例閥來(lái)控制液壓缸的準(zhǔn)確定位。采用此結(jié)構(gòu)最大的優(yōu)點(diǎn)是可以在不需要托起汽車底盤時(shí)將此結(jié)構(gòu)縮回到平板內(nèi)部，使整體結(jié)構(gòu)美觀、實(shí)用。設(shè)計(jì)將四個(gè)液壓缸同時(shí)可以固定在地基上，為考慮液壓缸的本身特性和升降高度，可以在維修車間挖一個(gè)坑 式的地基，將四個(gè)液壓缸充分牢固的通過(guò)地腳螺栓固定在地基上。所以外在負(fù)載的大小相對(duì)來(lái)說(shuō)是穩(wěn)定不變的，只有在加速度階段時(shí)將會(huì)產(chǎn)生整個(gè)平臺(tái)運(yùn)行的最大負(fù)載。在液壓系統(tǒng)中，油液的清潔度 對(duì)液壓系統(tǒng)的正常運(yùn)行有著至關(guān)重要的作用，所以在泵的出油口和油箱的回油口都安裝了過(guò)濾器，以此來(lái)保證油液的清潔度，這是液壓系統(tǒng)回路中不可缺少的附件。分流集流閥也稱同步閥，是集液壓分流閥、集流閥功能于一體的獨(dú)立液壓器件。為了使液壓系統(tǒng)中滿足提供安全壓力，不致由于壓力突然變高而對(duì)整個(gè)液壓系統(tǒng)造成不利影響甚至損壞某些液壓元件，所以采用溢流閥來(lái)用作安全閥防止液壓系統(tǒng)過(guò)載的保護(hù)。為了系統(tǒng)的油液滿足系統(tǒng)運(yùn)行的液壓油的要求和質(zhì)量，液壓系統(tǒng)應(yīng)該在進(jìn)油口和出油口處安裝過(guò)濾器。常用的比例閥可分為：比例壓力閥、比例流量閥和比例方向閥三種。為實(shí)現(xiàn)更高的同步精度和更加靈活的控制，設(shè)計(jì)并沒(méi)有采用傳統(tǒng)的控制閥進(jìn)行控制，而是擬采用更加新型的電液比例控制閥來(lái)進(jìn)行控制。為滿足液壓升降平臺(tái)的系統(tǒng)設(shè)計(jì)要求，實(shí)現(xiàn)平穩(wěn)的同步升降，以及設(shè)計(jì)所要達(dá)到的功能要求，擬定該系統(tǒng)采用液壓系統(tǒng)的閉環(huán)控制，用來(lái)滿足液壓系統(tǒng)的同步精度和控制要求，用以實(shí)現(xiàn)使四輪汽車在受控高度升降范圍內(nèi)同步升降，安全可靠地控制實(shí)現(xiàn)兩前輪、兩后輪、兩左輪、兩右輪的同步升降，并保證同步升降的精度。所以，對(duì)該升降平臺(tái)的進(jìn)一步研究和改進(jìn)，優(yōu)化系統(tǒng)性能和結(jié)構(gòu)的進(jìn)一步改善，彌補(bǔ)現(xiàn)有技術(shù)的缺點(diǎn)有著重要的意義。 在我國(guó)，雖然對(duì)這種液壓升降同步平臺(tái)的研制、生產(chǎn)起步較晚，但是隨著我國(guó)經(jīng)濟(jì)的快速發(fā)展，為了適應(yīng)我國(guó)在各領(lǐng)域所使用的液壓升降同步平臺(tái)發(fā)展的需求，走規(guī)?；?、標(biāo)準(zhǔn)化、集約化、產(chǎn)品配套化、實(shí)現(xiàn)機(jī)、電、液一體化技術(shù)在升降同步平臺(tái)上的應(yīng)用。當(dāng)前升降平臺(tái)的升降系統(tǒng)主要是靠液壓系統(tǒng)驅(qū)動(dòng)的，當(dāng)然不光靠液壓，還有柴油機(jī)電動(dòng)兩用旋轉(zhuǎn)式升降平臺(tái)，目前又出現(xiàn)了電瓶驅(qū)動(dòng)升降平臺(tái)，可以實(shí)現(xiàn)無(wú)級(jí)變速具有更安全、更方便、低噪音等優(yōu)點(diǎn)。為了避免以上缺點(diǎn)，要求更加精確地保證液壓升降平臺(tái)的同步升降精度，現(xiàn)在大多數(shù)液壓同步升降平臺(tái)逐步淘汰了各種傳統(tǒng)的液壓閥，采用更為精確控制的新型電液伺服閥、電 液比例閥以及電液數(shù)字閥等來(lái)控制液壓系統(tǒng)，實(shí)現(xiàn)同步精度高。無(wú)論哪一種，都要求可以滿足將汽車同步升降，不可以發(fā)生側(cè)偏，并且要求汽車底盤下方為空的，用以方便維修工人進(jìn)行維修作業(yè)這就要求升降平臺(tái)同步升降，平穩(wěn)運(yùn)行。 近年來(lái)，隨著汽車的使用量迅速增加，我國(guó)汽車業(yè)蓬勃發(fā)展，尤其是轎車行業(yè)。s rapid economic development, in order to adapt to China in various fields used by the synchronous hydraulic lifting platform development needs and take the largescale, standardized , intensive, product support services, achieving mechanical, electrical, fluid integration platform in the application of synchronous movements. The use of synchronous hydraulic lifting platform surface, the service has been expanding, is now in rapid development stage, and now hydraulic lifting platform reliability, security, easy operation and simple directness, and other aspects greatly improved, and with the the popularity and development of puter and mechanical, electrical, fluid integration progress of the study, major domestic and foreign panies have to pete with the puter (electronic) control system to improve overall performance and reduce the use of hydraulic ponents, machine, reducing the whole size and weight, improve the sensitivity of control and synchronization accuracy. In particular, the manufacturers actively introducing and digesting foreign advanced technology, development of new varieties, improving product technology and quality level, has been part of the hydraulic lifting platform synchronized at or close to the international level of similar products. Currently used in the automotive repair Hydraulic synchronous lift platform vehicle maintenance plays an important role in synchronous lifting platform on a variety of hydraulic valves, hydraulic cylinders, hydraulic pump station innovation and improvement, making a hydraulic lifting platform synchronization Smooth running, low noise, fast response, high precision synchronization, for the repair and maintenance of the car plays an irreplaceable role in a wide range prospects. Therefore, the lifting platform for further research and improvement, optimize system performance and structure to further improve to make up for the shortings of existing technology has important significance. The subject of the design of the hydraulic lifting platform main use of theoretical research and design, through the understanding and study of the hydraulic system, as well as existing control technologies and more indepth research and development, in the hydraulic system ponents and further understanding and learning , Combined with the modernization of hydraulic ponents and automation and control ponents within the hydraulic control through traditional hightech ponents and control elements of existing parative and prehensive application of the traditional hydraulic system, based on the research and design more innovative set of machines , Electricity, liquid in one of the hydraulic control system, makes the system more stable and faster to achieve the advantages. Hydraulic lift platform system, requires the ability to achieve fourwheeled vehicles in a controlled synchronous lifting height lifting range, to achieve safe and reliable control of the two front, two rear, two revolvers, two rounds of synchronous lifting the right and to ensure synchronous movements accuracy. The hydraulic lift system also must have a fast response speed, hydraulic power units, small size, pact structure, large power weight ratio, ease of manipulation and control, laborsaving convenience and easy to implement automated, with overload protection for high reliability requirements system, excellent technical performance, while ensuring synchronous hydraulic lifting platform can be anywhere in the vertical direction on a longer time (60 min or longer) within a reliable locking, the system can work continuously and reliably, the system energy efficient, easy to main