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机械类毕业论文中英文对照文献翻译 机械类 毕业论文 中英文 对照 文献 翻译 国外 典型 液压 系统 性能 比较

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【机械类毕业论文中英文对照文献翻译】国外几种典型液压锤液压系统及性能比较,机械类毕业论文中英文对照文献翻译,机械类,毕业论文,中英文,对照,文献,翻译,国外,典型,液压,系统,性能,比较

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国外几种典型液压锤液压系统及性能比较打桩锤的历史可追溯到15世纪，人们利用绳索吊起重物进行打桩。如今液压打桩锤已经广泛应用于桥梁、建筑、港口和码头等预制桩的基础施工作业，和传统的柴油打桩锤相比，液压打桩锤具有打桩效率高、无废气排放、噪声低、可调节打击能量、适应范围广等特点还可以用于水下打桩以及打斜桩等。 按照锤头的下落方式，液压锤可分为单作用液压锤和双作用液压锤。单作用液压锤即桩锤在自重作用下以自由落体方式下落。双作用液压锤即桩锤在自重和液压气动等外力的共同作用下以大于自由落体加速度下落。按照桩锤的吨位，液压锤可分为大型、中型和小型3种，桩锤重量3t以下的为小型液压锤；桩锤重量在310t之间的为中型液压锤；桩锤重量超过10t的为大型液压锤。小型液压锤适用于截面尺寸较小的钢桩和混凝土桩；中大型液压锤适用于港口码头、高层建筑、桥梁等工程的桩基施工。国外已经形成液压锤系列化产品，以满足各种基础施工的需要。近年来，国内桩工机械行业陆续展开液压锤的研究和开发工作，但大吨位、高性能的液压锤还不多，无法满足日益增长的工程需求。为此，国内基础施工中较多地采用了国外液压锤。本文主要比较分析国外几种典型液压锤的液压系统、特点和性能。1 典型液压打桩锤液压系统1.1 英国BSP单作用液压锤图1为英国BSP公司生产的一种单作用液压锤。桩锤上升阶段，电磁卸荷阀9通电，左位工作。电液比例阀10起溢流阀作用，调定液压系统工作压力。电磁换向阀3断电，上位接通，高压蓄能器4和变量泵1的出口油流进先导控制阀6控制缸的左、右两腔，先导控制阀6主阀的左位工作。此时，电磁换向阀7通电，左位工作，高压油通过换向阀7的左位流入油缸5的下腔。变量泵1和高压蓄能器4同时供油，活塞杆加速上升。液压缸5上腔的压力油经过先导控制阀6流入低压蓄能器8，经单向阀回油箱。低压蓄能器8吸收回油，减小压力波动。桩锤下降阶段，电磁换向阀3通电，下位工作，液压油进入先导控制阀6控制缸的右腔，使得先导控制阀6主阀的右位工作。液压缸5下腔的液压油则通过换向阀7的左位、先导控制阀6的大腔以及电磁换向阀3的下位，进入液压缸5的上腔，与液压泵一起向油缸上腔联合供油，锤体在重力作用下自由下落。桩锤冲击桩头动作完成之后，进入保压阶段。保压结束后电磁换向阀9通电，开始新的工作循环。1.2 芬兰JUNTTAN单作用液压锤图2为芬兰JUNTTAN公司生产的一种单作用液压锤。桩锤上升阶段，电磁换向阀6上位工作，主换向阀7下位工作。此时变量泵1和高压蓄能器5同时向液压缸8下腔供油，活塞杆加速上升并带动锤头上升。液压缸8上腔液压油流进低压蓄能器9回油箱。桩锤下降阶段即为当桩锤到达系统设定的高度时，电磁换向阀6下位工作，此时控制主换向阀7上位工作，高压油流入液压缸8的上腔，形成差动回路，桩锤加速下落。桩锤保压阶段，为防止桩的反弹，桩锤在桩上停留很短的一段时间，即保压时间。保压结束后，电磁换向阀6动作使主换向阀7换向，桩锤开始上升，开始新的循环。桩锤停止工作时，溢流阀2、卸荷阀4均打开与油箱连通，来自变量泵1的压力油直接流回油箱，液压缸8的上、下腔相连接，压力相等，活塞停至液压缸8最低端位置。1.3 荷兰IHC双作用液压锤荷兰IHC公司推出了一种双作用液压锤（图3)。桩锤上升阶段，电磁换向阀7闭合，电磁换向阀5断开，液压泵9和高压蓄能器8同时向油缸下腔供油，锤头1抬起。此时氮气室6的气体被压缩而储存能量。桩锤下降阶段，电磁换向阀7断开，电磁换向阀5闭合，桩锤开始下降。氮气室高压氮气释放储存能量，桩锤在自重和氮气室6双重作用下加速下降撞击桩体，完成打击作用。桩锤下降同时，液压泵9向高压蓄能器8供给液压油。由于回油管路较长，低压蓄能器4吸收液压锤排出的液压油以保证桩锤加速下降。当两个电磁换向阀都在闭合位置时，液压油回油箱，液压系统卸载。2 打击频率与打击能量比较 1）打击频率 液压打桩锤的打击频率取决于桩锤各阶段的工作时间。工作时间越短，打击频率越高。由于液压打桩锤下落加速度一般都设计在一个重力加速度或以上，下落时间很短，打击频率主要取决于上升时间。单作用液压锤上升过程中，液压泵和高压蓄能器同时供油，上升速度快，打击频率较高；双作用液压锤在桩锤上升时，液压泵同时向油缸和高压蓄能器供油，桩锤上升较慢，打击频率较低。荷兰IHC推出的S型双作用液压锤以及芬兰JUNTTAN生产的HHKA型单作用液压锤在上升阶段，液压泵和高压蓄能器同时向液压缸下腔供油，具有较高的打击频率，达到60次/min。2） 打击能量 打击能量与锤体自重、上升高度、液压缸上腔油液（或是气体）的压力以及打击加速度的大小等参数有关。单作用液压锤打桩时油缸上腔为低压腔，与回油路相连，主要靠自重以近似自由落体方式打击桩体，打击能量较低。双作用液压锤依靠液压力或气动力加上锤体自重，一般打击能量较大。表1为几种典型液压锤主要性能比较 3结论 通过比较国外几种典型液压打桩锤，可知英国BSP的CGL370型和荷兰IHC的S型系列液压锤打击频率较高，芬兰JUNTTAN的HHKA型液压锤打击频率较低。 荷兰IHC的S型和芬兰JUNTTAN的HHKA型液压打桩锤都具有较高打击能量，且可调节的范围很大，英国BSP的CGL370系列为单作用方式液压打桩锤，打击能量较低，可调范围有限。 荷兰IHC的S型液压锤的液压系统简单，结构紧凑，其他公司的液压锤液压系统相对复杂。IHC液压锤油缸设有氮气室，调节压力从而调节打击能量，最大打击加速度可达2g，适合于大吨位打桩作业。Comparison of hydraulic system and performance of several typical hydraulic hammer abroad Hammers history can be traced back to fifteenth Century, people use the rope to lift a weight of piling. Today, hydraulic pile hammer has been widely used in bridges, buildings, ports and terminals, such as precast pile foundation construction operations, and conventional diesel pile hammer compared, hydraulic piling hammer with pile driving high efficiency, no waste gas emission, low noise, adjustable blow energy, adapt to a wide range of characteristics can also be used for under water piling and beveling pile. According to the whereabouts of hammer, hydraulic hammer can be divided into single and double acting hydraulic hammer hydraulic hammer. Single acting hydraulic pile hammer hammer falling by a free falling under gravity. Double acting hydraulic pile hammer hammer under gravity and hydraulic pneumatic force combined with the greater acceleration of free fall drop. According to the tonnage of the pile hammer, hydraulic hammer can be divided into large, medium and small three, below the pile hammer weight 3T for small hydraulic hammer, the hammer weight between 3 10t for medium-sized hydraulic hammer; hammer weight is more than 10t for large hydraulic hammer. Small hydraulic hammer is suitable for steel piles and concrete piles with smaller section size. The large hydraulic hammer is suitable for pile foundation construction of port, high-rise building and Bridge etc. Has formed a series of hydraulic hammer products, in order to meet the needs of various basic construction. In recent years, the domestic pile industry machinery industry has started the research and development of hydraulic hammer, but the large tonnage, high performance hydraulic hammer is not much, can not meet the growing demand for engineering. Therefore, the domestic basic construction uses the foreign hydraulic hammer frequently. This paper mainly analyzes the hydraulic system, features and performance of several typical hydraulic hammer abroad.1 typical hydraulic piling hammer hydraulic system1.1British BSP single acting hydraulic hammer A single - acting hydraulic hammer for the production of BSP, UK. The stage of the rise of the pile hammer, the electromagnetic unloading valve 9 power, the left position. Electro-hydraulic proportional valve 10 overflow valve role, setting hydraulic system working pressure. Solenoid valve 3 power off, the upper connected, high pressure accumulator 1 and variable pump outlet oil flow into the pilot control valve 6 control cylinder left and right two chamber, pilot control valve 6 main valve left position. At this point, the solenoid valve 7 power, the left position, the valve through the valve 7 of the left into the cavity of the cylinder 5. Variable pump 4 and high pressure accumulator 1 at the same time, the piston rod to accelerate the rise. Hydraulic cylinder 5 pressure oil through the pilot valve 6 into the low pressure accumulator 8, the check valve back to the tank. Low pressure accumulator 8 absorbs oil back and reduces pressure fluctuation. The lower phase of the hammer, the solenoid valve 3 power, the lower position, hydraulic oil into the pilot control valve 6 control cylinder right chamber, so that the pilot control valve 6 main valve right position. Hydraulic oil of the hydraulic cylinder 5 inferior vena is through the reversing valve 7 left, pilot control valve cavity and an electromagnetic reversing valve 3 and lower into the hydraulic cylinder 5 of the chamber, and a hydraulic pump together to the upper chamber of oil cylinder with oil, a hammer body under the action of gravity free fall. After the hammer impact pile head is finished, the pressure is entered into the holding phase. After the end of the pressure of the solenoid valve 9 power, starting a new working cycle.1.2 Finland JUNTTAN single acting hydraulic hammer A single acting hydraulic hammer for JUNTTAN production in Finland. The rise of the pile hammer, the solenoid valve 6, the main valve 7 lower position. The 1 variable pump and high pressure accumulator and hydraulic cylinder 5 to 8 lower fuel, accelerating piston rod and drive the hammer up. Hydraulic cylinder 8 the upper chamber hydraulic oil flow into the low-pressure accumulator 9 return to the fuel tank. Pile hammer falling stage is when the pile hammer arrived to set up the system of high, electromagnetic reversing valve 6 lower, then the control main reversing valve 7 upper work, high pressure oil into hydraulic cylinder 8 of the chamber, forming a differential circuit, the pile hammer acceleration whereabouts. The holding period of the hammer is to prevent the rebound of the piles, and the pile hammer is short for a short period of time. After the end of the pressure, the solenoid valve 6 action to the main valve 7 commutation, the pile hammer began to rise, starting a new cycle. Pile hammer stops working, relief valve 2, unloading valve bearing 4 were opening is communicated with the oil tank, from variable pump 1 direct pressure oil flows back to the oil tank, hydraulic cylinder 8, inferior vena connected, equal pressure, the piston to stop hydraulic cylinder 8 the lowest end position.1.3 Holland IHC double acting hydraulic hammer Holland IHC Corporation introduced a double acting hydraulic hammer (Figure 3). The rising phase of the pile hammer, the electromagnetic reversing valve closed, electromagnetic reversing valve 5 is disconnected, the hydraulic pump and high pressure storage energy device at the same time to supply the cylinder cavity, hammer head 1 lift. At this point the gas of the nitrogen chamber 6 is compressed and stored energy. The decline of the hammer, the solenoid valve 7 open, the solenoid valve 5 closed, the pile hammer began to fall. Nitrogen chamber high pressure nitrogen release the storage energy, the pile hammer in the weight and nitrogen chamber 6 under the dual role of the impact of the acceleration of the impact of the pile, the completion of the blow. The hydraulic pump 9 supplies hydraulic oil to the high pressure accumulator 8 while the hammer is falling. Due to the long back oil pipeline, the low pressure accumulator 4 can absorb hydraulic oil from the hydraulic hammer to ensure the acceleration of the pile hammer. When the two solenoid valve are in the position of the hydraulic oil back to the tank, hydraulic system unloading.2 Comparison between strike frequency and strike energy 1) the frequency of the hammer against the frequency of the hydraulic hammer is determined by the working hours of the hammer stages. The shorter working hours, the higher the frequency of the fight. As the hydraulic piling hammer drop acceleration are generally designed in a gravity acceleration or above, the whereabouts of the time is very short, the fight frequency mainly depends on the rise time. Rise process of the single action hydraulic hammer, hydraulic pump and high pressure storage can also supply, rising fast, against high frequency; double acting hydraulic hammer pile hammer to rise, the hydraulic pump and oil to the oil cylinder and the high-pressure storage oil supply device, slower rise pile hammer against low frequency. IHC Hydrohammer launched s type double acting hydraulic hammer and Finland JUNTTAN production of the the HHKA single acting hydraulic hammer during the rising phase, hydraulic pump and high pressure storage can also to the hydraulic cylinder cavity oil, with high attack frequency, up to 60 times per minute. 2) the fight against the energy and the weight of the hammer, the height of the pressure, the pressure of the oil fluid (or the gas) and the size of the acceleration. Single acting hydraulic pile hammer cylinder cavity for the low pressure chamber, and the return oil line connected, depends mainly on the weight in order to approximate the free falling body fight pile, fight low