附录
Steeplechase lifting device structure and design Lifting Gear steeplechase and design of the structure of the lifting mechanism is relatively traditional, the tail plate lifting mechanism using only a single fuel tank, so that the hydraulic system of the pipe is simple, convenient control and high reliability of the hydraulic system, and and ease of installation. The above analysis and calculation of the institutions such as the structure and properties of the mathematical relationship between parameters. To promote inter-related with the sleeve of the friction and wear, the sleeve guide groove angle and flip angle and a high degree of adaptability, such as lifting will be subject to further research and the analysis of the structure of hair[17].
Lifting Gear steeplechase vehicle movements in foreign countries as the rear door (end plate), its installed in the car named after the tail. In this paper, according to national standards call a lifting gear steeplechase. Steeplechase a lifting device installed on the van in the carriage of goods, not only to demonstrate its proprietary water-resistant dust-proof function, but also in the loading and unloading of goods mechanization achieved.
1. steeplechase development Lifting Gear
Lifting Gear steeplechase development, largely in foreign countries can be divided into four periods. The first generation of
products in the 30's at the end of this century, characterized mainly lifting cylinder, and the steeplechase manually turned on, from or about the quality of 500kg, steeplechase (also known as loading platforms) touchdown angle 9 ° ~ 10 °. At present, this product in South-East Asia, Japan still in use, 90 years, is still the United States by the new development. Second-generation products in the early 50's the European market, in the first generation of products based on the increase of turnover to close the fuel tank. Lift and flip the fuel tank by two to achieve independence. The most common is a type 4 tank, but also of the double. Lifting the quality of more than 500 kg, platform loading touchdown angle 10 °, flip action control based on the experience of the operator. The products are mainly used in the Americas and Southeast Asia. Third-generation products in the 70's at the end of the European market is the second generation of products based on the increase in the fuel tank of the fifth. Only the fuel tank of the hydraulic system in the relative positions of the main effect of memory function, so that touchdown to loading platform, off the flip action is no longer controlled by the operator by the hydraulic control system itself, so that the process is relatively smooth take-off and landing and security. Touchdown angle is generally 8 ° ~ 10 °. If it doubles as a car door, and a result of increased platform size, angle may also be less than 8 °. At present these products to Europe and America in general. Fourth-generation products during the
early 90s, and its hydraulic system and function of principles with the third-generation products, only an increase of the fuel tank the size of memory, so memory and increase the scope of action. It is different from the third generation of the product lies in the loading platform to increase its special structure, from one body to two activities connected to the platform after the touchdown, not only can automatically flip, but there is a sinking action to achieve the touchdown angle 6 °, even in 6 below. At present, the products in the Netherlands, Yugoslavia and China has applied for a utility model patent. The domestic market has been stereotyped. From the performance, security, reliability results, the fourth-generation products will be gradually replaced the second and third generation products. The first generation of products, because of its simple structure, light weight, although the technical content, but with the advantages of easy maintenance, etc., in developing countries will still have a certain market. Lifting Gear steeplechase development in China only a few things more than a decade. The former Ministry of Posts and Telecommunications in 1985 imported from Japan with a number of lifting devices steeplechase van. Since then, by the Special Purpose Vehicle Institute of Hanyang, Hubei auto parts plant and Communication Ministry of Posts and Telecommunications Machinery Factory Mingshui three cooperation made the research and development, which lasted more than two years, due to various reasons can not be put into use. In
early 1988, Ministry of Posts and Telecommunications Communications Machinery Factory Mingshui technical staff, continue to develop. Post Office in Beijing to help the strong, thanks to the efforts of the past four years, increasing product quality stabilized. Early use of domestic products as a driving force for car engines. To achieve in 1992 a car battery as the driving force of the hydraulic pump station. After 1992, lifting gear steeplechase van due to the development of domestic and began to develop, the skill level is gradually close to the international. According to the current understanding of the situation, the domestic production steeplechase of the enterprises, including Lifting Gear Mingshui, such as posts and telecommunications equipment factory at least five, the product structure have a single-cylinder, four-cylinder, five-cylinder and the early 90's and the latest U.S. technology-based The five-cylinder technology. Although the product mix in the form, the international four-generation products are produced in China, but its development is still in its infancy. The expansion of the domestic market, but also the need for inter-and opportunities. Speaking time may not last long, from the varieties of speaking, a short period of time will still exist a variety of forms, but in the end may be the single-cylinder and five-cylinder products.
2. steeplechase of the basic principles of lifting gear
Lifting Gear steeplechase varieties are numerous, but the basic fundamental tenets of the original but it is the same, that is, parallel four-bar linkage of the practical application of the principle of parallel move, it is two sets of parallel four-bar linkage, sub-put longeron on both sides of car, synchronous movements, while the DCE is the above mentioned loading platform (steeplechase). Design, the following three issues to be resolved: BC under the driving force for rotation; BC under the role of rotational dynamics and the role of the form of points; CD under the C-point after touchdown, there must be a rotationaround the point D moves to E end of touchdown to facilitate loading and unloading of goods.
2.1 Power System
Steeplechase early in the development of lifting devices for the automotive engine through the oil pump driven from power-driven devices. Working hours as a result of the need to idle the engine running, is now seldom used. At present, the basic use of micro-driven hydraulic pump station, a car battery for power source. Micro-pump station has the basic components of DC motors (with the car battery voltage to match), control valves, gear pumps, combination valve (overflow, cutting one-way), and the fuel tank, electric start switch, control switch and so on. According to different vehicle battery voltage, DC motors are 12 V, 24 V are two different power according to the weight since there are 018
kW, 110 kW, 112 kW, 115 kW, 2 kW, 3 kW and so on. Gear pump according to the number of tanks (mainly hydraulic flow) and the hydraulic system pressure to choose, there is displacement 1 ml, 112 ml, 116 ml, 210 ml, 215 ml, 410 ml wide range of specifications, the maximum output pressure gear pump up to 25M Pa. Hydraulic Pump Station has been the international product quality is stable, less quality of domestic products, mainly the quality of the solenoid valve or volume too large, however.
2.2 The form and the role of driving force transmission point[18]
Both rely on power through the pressure of hydraulic oil system from the fuel tank to the BC transmission poles. Fuel tanks and installation of the number of different positions, and to take the DC bar the difference in the rotation, the power transmission lines are also different. a1 cylinder on the front. Hinge for a long shaft B, the two parallel four-bar linkage mounted on the shaft at both ends, a shaft connected to the middle arm, then the fuel tank of the piston rod end of the fuel tank on the other side of the fixed bracket on the transmission of power as follows: oil tumbler cylinder → → BC rod shaft, the working process in Figure 2. b1 on the rear cylinder. The fuel tank 24 is located in the middle of linkage, the two four-bar linkage in the middle of the BC bar with fixed beams together, the middle beam connecting rod and the fuel tank, fuel tank connected to the other side with the stent. c1
four-cylinder and five-cylinder type. Five-cylinder structure of the memory of the fifth hydraulic cylinder is a cylinder in the hydraulic circuit, the loading platform to participate in only touchdown after the reversal platform action, without reference platform for take-off and landing, and its basic structure with the same four-cylinder. Four-cylinder under the structure of the fuel tank of BC, which is different from the distinction between single-cylinder.
2.3 CD under the rotation
CD of the rotation pole, four-cylinder with five-cylinder fuel tank of the type of contraction depend on the realization of single-cylinder rear-mounted on, CD can not be achieved under rotation (but can be reversed to achieve at the highest position, because the structure of more complex, and I shall not introduce) ; for the single-cylinder front-on, based on the structural changes under BC achievable. The actual design, AD is also required under certain technical processing to meet the requirements. In addition, note that, D CE articulated only in the D point, the other type for the D, C two hinged.
3 steeplechase lifting device to determine the technical parameters
Lifting Gear steeplechase main technical parameters: Rated lifting the quality of travel movements, take-off and landing speed, shot size, platform size, operating voltage and power motor, gear pump row weight (rated output flow), control valves, the type and quantity of and
the fuel tank of the bore and stroke, rated working pressure. Under normal circumstances, the beginning of the design parameters are known to width and height from the floor, battery voltage and capacity, beam spacing and beam auto height and size of rear overhang. Known p a r a m e t e r s a r e t h e f u n d a m e n t a l b a s i s f o r d e s i g n.
随车起重装置的结构与设计
相对传统的举升机构,该举升机构只采用了液压缸,使液压系统的
管路简单,控制方便,液压系统的可靠性高,且安装方便。上述的分析与计算,为该机构建立了结构与性能等参数间的数学关系。有关推销与套筒间的摩擦与磨损,套筒导槽角和翻转角度与举升高度的适应性等问题,将有待进一步的分析研究和结构发。
随车起重装置在国外称为随车吊。本文按国家标准称其为随车起重装置。一辆安装了随车起重装置的厢式货车在货物运输中, 不仅显示其防雨防尘的专有功能,而且在货物的装卸方面实现了机械化。
1随车起重装置的发展
随车起重装置的发展, 在国外大体上可分为四个时期。第一代产品产生于本世纪30 年代末, 其特点主要是单缸举升, 而栏板翻转靠手动, 起升质量为500kg 左右, 栏板(又称载物平台) 触地倾角9°～10°。目前, 这种产品在东南亚、日本仍在使用, 90 年代, 还在美国得到了新的发展。第二代产品产生于50 年代初的欧洲市场, 在第一代产品的基础上增加了翻转关门油缸。举升与翻转分别由二个独立油缸实现。最常见的是四只油缸的型式, 也有双缸的。起升质量在500 kg 以上, 载物平台触地倾角10°, 翻转动作凭操作者经验控制。该种产品目前主要用于美洲及东南亚地区。第三代产品产生于70 年代末的欧洲市场, 是在第二代产品的基础上增加第五只油缸。这只油缸在液压系统中主要起相对位置的记忆功能, 使载物平台触地、离地的翻转动作不再由操作者控制而由液压系统本身控制, 从而使升降过程相对平稳与安全。
触地倾角一般为8°～10°。若兼作厢门用, 因平台尺寸增大, 倾角也可能小于8°。目前该类产品普遍用于欧美地区。第四代产品产生于90 年代初, 其液压系统及功能原理同第三代产品, 只增加了记忆油缸的尺寸, 使记忆动作的范围进一步增大。它不同于第三代产品的关键在于其载物平台增加特殊结构, 由一体改为两体活动联接, 使平台触地后不仅能自动翻转, 而且有一个下沉的动作, 使触地倾角达到6°, 甚至在6以下。目前该产品在荷兰、南斯拉夫和中国已申请了实用新型发明专利。国内已有定型产品投放市场。从操作性能、安全可靠性等使用效果上, 第四代产品将逐渐取代了第二、三代产品。而第一代产品,由于其结构简单, 重量轻, 虽然技术含量低, 但具有便于维修等优点, 在发展中国家将仍有一定的市场。随车起重装置在国内的发展只是近十几年的事情。1985 年原邮电部从日本进口了一批装有随车起重装置的厢式车。此后, 由汉阳专用汽车研究所、湖北汽车配件厂和邮电部明水通信机械厂三家合作进行了国产化研制开发, 历时两年多, 却因多种原因而未能投入使用。1988 年初, 邮电部明水通信机械厂组织技术人员, 继续研制。在北京市邮政局的大力协助下, 经过近四年的努力, 产品质量日渐趋于稳定。国产化产品早期用汽车发动机作为动力。1992 年实现以汽车蓄电池作为液压泵站的驱动力。1992 年以后, 随车起重装置因国内厢式车的发展而开始发展起来, 技术水平也逐渐向国际靠近。据目前了解的情况, 国内生产栏板起重装置的企业包括明水邮电通信设备厂等至少有5 家, 产品结构型式有单缸、四缸、五缸及90 年代初的美国技术及最新型的五缸技术。尽管在产品结构形式上, 国际
上的四代产品均在国内都有生产, 但就其发展而言, 仍处于起步阶段。国内市场的扩展, 还需要间与机遇。从时间上讲可能不会太久, 从品种上讲, 短时期内将仍是以多种型式并存, 但最终可能是单缸产品和五缸产品为主。
2随车起重装置的基本原理
随车起重装置的品种虽多,但其基本原但其基本原理却是相同的,即平行四连杆机构的平行移动原理实际应用中, 是两组平行的四连杆机构,分置于汽车纵梁两侧, 同步动作, 而DCE 即为上文所说的载物平台(栏板)。设计时,须解决以下三个问题:BC杆转动的动力; BC杆转动动力的作用点及作用形式;CD 杆在C 点触地后, 必须有一个绕D 点转动动作,以便E端触地,方便货物装卸。
2.1动力系统
随车起重装置在发展初期为汽车发动机通过取力器带动油泵驱动。由于工作时发动机需要怠速运转, 现已很少采用。目前基本都采用微型液压泵站驱动, 以汽车电瓶为动力源。微型泵站的基本构成有直流电动机(与汽车电瓶电压匹配)、控制阀、齿轮泵、组合阀体(溢流、单向节流) 以及油箱、电机启动开关、控制开关等。根据汽车电瓶电压不同, 直流电机有12 V、24 V 两种, 功率根据起重量不同有018 kW、110 kW、112 kW、115 kW、2 kW、3 kW 等。齿轮泵根据油缸数量(主要是液压流量) 和液压系统工作压力选择, 排量有1 m l、112 m l、116 m l、210 m l、215 m l、410 m l 多种规格, 齿轮泵最大输出压力可达25M Pa。液压泵站国际产品的质量已很稳定, 国内产品质量稍差, 主要是电
磁阀质量不过或体积偏大。
2.2动力传递形式及作用点
动力均靠液压油经过压力系统由油缸传递到B C 杆上。油缸数量和安装位置不同, 以及采取的D C 杆的转动方式的差异, 其动力传递的路线也不同。a1 单缸对中前置。铰链B 为一长转轴, 两平行四连杆机构安装于轴的两端, 轴的中间连一转臂, 接油缸活塞杆端, 油缸另一端固定于支架上, 力的传递为: 油缸→转臂转轴→B C 杆, 工作过程如图2。b1 单缸对中后置。油缸位于两四连杆机构的中间位置, 两四连杆的B C 杆在中间用横梁固定连为一体, 梁中间与油缸活塞杆联接, 油缸另一端与支架联接。c1 四缸及五缸型式。五缸结构中的第五缸是液压记忆缸, 在液压回路中, 只参与载物平台触地后平台的翻转动作, 而不参平台升降, 其基本结构与四缸相同。四缸结构中B C 杆均为油缸, 这是不同于单缸的区别。
2.3CD 杆的转动
CD 杆的转动, 四缸与五缸型式依靠油缸的收缩实现, 单缸对中后置式, CD 杆无法实现转动(但可在最高位置实现翻转, 因结构较复杂, 在此不作介绍) ; 对于单缸对中前置式, 是以B C 杆的结构改变实现的。实际设计中,A D 杆也需要作一定的技术处理才能满足要求。另外还要注意一点,D CE 只在D 点铰接, 其它型式为D、C 两点铰接。
3随车重装置技术参数的确定
随车起重装置的技术参数主要有: 额定起升质量、升降行程、升降速度、杆件尺寸、平台尺寸、电动机工作电压及功率、齿轮泵排重(额
定输出流量)、控制阀型式及数量和油缸的缸径及工作行程、额定工作压力等。一般情况下, 设计开始时已知的参数为地板距地高度、电瓶电压及容量、汽车纵梁间距及纵梁高度和汽车后悬尺寸等。已知参数是进行设计的基本依据。