_高空作业车的液压系统开题报告

无锡太湖学院毕业设计（论文）开题报告题目： 高空作业车的液压系统 信机 系 机械工程及自动化专业学 号： 0923046 学生姓名： 贡涛 指导教师： 林承德 （职称：教授 ） （职称： ）2012 年 11 月 课题来源江苏省苏州金龙客车有限公司科学依据（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）高空作业车是用来运送工作人员和工作装备到指定高度进行作业的特种车辆，是将高空作业装置安装在汽车底盘上组成的。高空作业装置包括工作臂、回转平台、副车架、工作斗、液压系统和操纵装置等。现在的高空作业装置具有操作平顺、工作稳定、自动调速、安全可靠等优点，大大提高了空中作业的工作效率。高空作业车是利用汽车底盘作为行走机构，具有汽车的行驶通过性能，机动灵活，行驶速度高，可快速转移，转移到作业场地后能迅速投入工作，因此被越来越多的应用在工程建设、工业安装、设备检修、物业管理、航空、船舶、石化、电力、影视、市政、园林等许多行业，是近几年来国内发展最快的专用汽车产品之一。研究内容1、设计任务：高空作业车的液压系统设计2、机器用途：通用型，适用于建筑、安装、管道铺设等高空作业。3、工作环境：风力六级以下，温度-2030 ，无腐蚀性极易爆易燃性气体。4、作业部分主要技术参数 最大作业高度： 11-12米 最大作业半径： 5.5米 回转角度： 360 额定平台载荷： 200kg 操作方式： 下操作、上操作可以任意选择。 支腿形式/数量： H型/4 旋转速度： 0-3r/min 两支臂变幅时间：起臂：t70s 落臂：t6045s 支腿收放时间： 收支腿：t60s 放支腿：t60s拟采取的研究方法、技术路线、实验方案及可行性分析1、回转台左右均可以全周回转360。2、起升和旋转可以同时互不干涉的动作。3、垂直支腿在高空作业车非工作状态下可以自由缩放。4、水平支腿在高空作业车非工作状态下可以自由的扩放支腿的支承范围。5、制动液压缸可以随时制动回转马达的转动。动作平稳、安全可靠、操作方便、体积小、自重轻研究计划及预期成果本课题金龙客车的高空作业车液压系统为对象，对该车重要系统-液压部分系统进行设计和研究，以实现高空作业车的工作稳定、可靠，安全。主要研究过程如下：1、 收集、分析、消化原始资料，了解熟悉目前高空作业车液压系统的设现状，控制方法，主要元器件及有关技术参数分析存在的问题。2、 液压系统设计确定液压系统方案确定液压系统控制方式液压元器件的选择和有关计算3、 绘制标准液压系统工作图 预期成果：制定出合理液压系统方案以致使工作臂和支腿实现预定的运动，保证作业车安全可靠的运行。特色或创新之处液压传动与机械传动、电气传动相比有以下主要优点： (1) 在同等功率情况下，液压执行元件体积小、重量轻、结构紧凑。例如同功率液压马达的重量约只有电动机的1/6左右。 (2) 液压传动的各种元件，可根据需要方便、灵活地来布置； (3) 液压装置工作比较平稳，由于重量轻，惯性小，反应快，液压装置易于实现快速启动、制动和频繁的换向；(4) 操纵控制方便，可实现大范围的无级调速(调速范围达2000：1)，它还可以在运行的过程中进行调速； (5) 一般采用矿物油为工作介质，相对运动面可自行润滑，使用寿命长； (6) 容易实现直线运动； (7) 既易实现机器的自动化，又易于实现过载保护，当采用电液联合控制甚至计算机控制后，可实现大负载、高精度、远程自动控制。 (8) 液压元件实现了标准化、系列化、通用化，便于设计、制造和使用。已具备的条件和尚需解决的问题 已具备的条件：电脑；相关开发软件；部分技术资料。 尚需解决的问题：学习UG软件；确定产品的结构尺寸和技术要求；逆向设计建立三维数模；总成运动仿真校核。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 日翻译部分英文部分： The hydraulic actuator is the hydraulic pump provides hydraulic energy into mechanical energy conversion device, which comprises hydraulic cylinders and hydraulic motors. Output rotational movement of the hydraulic actuator is a hydraulic motor habits, while the output of the linear movement (including output swing movement) of the hydraulic actuator element is referred to as the hydraulic cylinder. A hydraulic motor characteristics and classification The hydraulic pump and the hydraulic motor is a reversible hydraulic components, from the viewpoint of energy conversion can be input to any one of the hydraulic pump working fluid, it becomes a hydraulic motor working conditions; Conversely, when the main shaft of the hydraulic motor by the outer the torque driven to rotate, but also becomes hydraulic pump conditions. Because they have the same basic structural elements - sealed and may periodically change the volume and corresponding with the oil bodies. However, due to different operating conditions of the hydraulic motor and a hydraulic pump, the performance requirements are not the same, so there are still many differences between the hydraulic motor and a hydraulic pump of the same type. First hydraulic motor should be capable of being reversed and thus requires that its internal structure symmetry; hydraulic motor speed range needs to be large enough to have certain requirements, in particular its minimum steady speed. Therefore, it is usually the use of rolling bearings or hydrostatic bearings; second hydraulic motor due to an oil under the conditions of the input pressure, and thus do not need to have a self-priming ability, but needed the certain initial sealing performance, in order to provide the necessary starting torque. Due to the existence of these differences, so that the hydraulic motor and the hydraulic pump is relatively similar in structure, but not reversible. Hydraulic motor in accordance with knot plum type can be divided into gear, vane, piston, and other types. Divided into high and low speed two categories according to the hydraulic motor rated speed. Higher than the rated speed 500r/min is a high-speed hydraulic motor, rated speed less than 500r/min is a low-speed hydraulic motor. The basic types of high-speed hydraulic motor gear, screw, vane and axial piston. Their main characteristics is the high speed, small moment of inertia, easy starting and braking, adjust high sensitivity (speed and commutation). Often, speed hydraulic motor output torque (N m of only tens to hundreds of N m), it is also known as a high-speed low torque hydraulic motor. Basic types of low-speed hydraulic motor is a radial piston type, in addition to low-speed axial piston, vane and gear structure type, the main features of the low-speed hydraulic motor is large displacement volume low speed (sometimes up to a few turns per minute or even a few tenths of turn), it can be directly connected with the working bodies do not need to slow down the device, the transmission mechanism greatly simplified, usually low-speed hydraulic motor output torque (up to several thousand N m tens of thousands N m), it is also known as the low speed high torque hydraulic motor. Second, the hydraulic motor operating principle 1 Vane hydraulic motor Due to the role of pressure oil, the uneven rotor torque. Vane hydraulic motor output torque and the displacement of the hydraulic motor and the hydraulic motor and out of the pressure differential between the ports, its speed is determined by the size of the input flow rate of the hydraulic motor. Hydraulic motors are generally required to reversing radial vane hydraulic motors leaves placed. In order to make the blade root always through the oil pressure in the back pressure chamber Walter blade root path should be set to a one-way valve, in order to ensure that the vane hydraulic motor in the normal pressure oil Walter, the top of the blade and The inner surface of the stator in close contact in order to ensure a good seal, and therefore should be set to the blade root to the preload spring. Vane hydraulic motor small size, small moment of inertia, quick action, applicable to the commutation frequency is higher, but the large amount of leakage, low-speed operation is unstable. Vane hydraulic motors are generally used for high speed, torque is small and the operational requirements of sensitive occasions. 2 radial piston hydraulic motor Figure 3-2 radial piston hydraulic motor schematic when pressure oil fixed oil distribution shaft 4 window into the bottom of the cylinder inner plunger 1, the plunger extends outwardly tightly top live in the inner wall of the stator 2 and the eccentricity e, due to the presence of the stator and the cylinder block. The plunger in contact with the stator, the stator of the reaction force of the plunger. The force can be decomposed into two components. When the fluid pressure acting on the bottom of the plunger p, plunger diameter D, the angle between the force and Duration, they were and produce a torque force on the cylinder, the cylinder rotation. Cylinder and then connected to the drive shaft through the end face outward output torque and speed. The above analysis of a torque generated by the plunger role in the pressure chamber there are several plunger, the plunger torque generated by rotation of the cylinder, and the output torque. Radial piston hydraulic motor is used for low speed and high torque. 3 axial piston motor Axial piston pump valve with flow, other forms of principle can be used as a hydraulic motor, axial piston pumps and axial piston motor is reversible. Axial piston motor works as shown, with the oil pan and the swash plate fixed and 5 and the cylinder of the motor shaft connected to rotate together. When the pressure oil through the oil pan window into the cylinder plunger hole, the plunger 3 in the pressure oil under the overhang, the plunger against the swashplate swashplate 3 generates a method to the reaction p This force can be decomposed into axial and vertical component where. Where and plunger hydraulic pressure phase equilibrium, where the plunger creates a torque on the center of the cylinder, driven by the motor shaft rotates counterclockwise. Axial piston motor instantaneous torque pulsation. If you change the motor oil pressure input direction, the motor shaft 5 rotates clockwise. The inclination of the swash plate is a change, i.e. the change of the displacement, not only affects the torque of the motor, but also affects its speed and direction. The greater the inclination angle of the swash plate, the greater the torque is generated, the lower the speed. 4. Gear hydraulic motor Gear motor on the structure in order to adapt to reversing requirements out of the oil port equal to the symmetry have separate external case drain the bearing portion of the leakage of oil leads to the outside of the housing; uses rolling in order to reduce the start friction torque; torque in order to reduce the The pulsating hydraulic gear motor Teeth more than the number of teeth of the pump. Gear hydraulic motor worse by the dry tightness, Yung rent less efficient input pressure is not too high, you can not have a greater torque. With the change of position of the engagement point and the instantaneous speed and torque varies, the hydraulic gear motor therefore only suitable for the occasion of the high speed and small torque. General with a dry construction machinery, agricultural machinery, and machinery and equipment less demanding torque uniformity. 1. The displacement of the hydraulic motor, the displacement and torque relationship The output torque of the hydraulic motor working in size is determined by the load torque. However, to promote the same size of the load, the working cavity of the pressure of the motor is lower than the pressure of the working cavity small motor, so that the size of the working cavity is an important symbol of the hydraulic motor ability to work. Representation of the size of the working cavity of the hydraulic motor and the hydraulic pump, which means that CC V. The displacement of the hydraulic motor is an important parameter. Can be calculated at a given pressure, the size of the hydraulic motor can output torque, the size of the working pressure under a given load torque motor may also be calculated according to the size of the CC. When the hydraulic motor into the pressure difference between the oil outlet for the input of the hydraulic motor flow rate q, the theoretical torque of the hydraulic motor output, the angular velocity, if not taking into account the loss of hydraulic hydraulic pump output power should be all converted to hydraulic the mechanical power of the motor output, i.e. Because, so the theoretical torque of the hydraulic motor 2. The mechanical efficiency of the hydraulic motor and start the mechanical efficiency Hydraulic motor internal inevitably the presence of a variety of friction, the actual output torque than the theoretical torque smaller, i.e. Where the mechanical efficiency of the hydraulic motor. In addition, under the same pressure, the output torque of the hydraulic motor begins to turn from rest to start-up state torque than the operating load to the hydraulic motor to start the cause difficulties, so the start-up performance of the hydraulic motor is very important. The starting torque is reduced because the maximum coefficient of friction in a stationary state, appears on the friction surface the relative sliding coefficient of friction is significantly reduced, which is the general nature of the mechanical friction. Hydraulic motor, the stationary state lubricant film is squeezed out, basically becomes dry friction. And the motor begins to move, with the establishment of the lubricant film, friction immediately drop and reduced increases with the sliding velocity and film thickening. Hydraulic motor start-up performance indicators start mechanical efficiency, which was expressed as wherein the starting torque of the hydraulic motor. Different types of hydraulic motors, internal force components of the force balance is different, the size of the friction, and so are not the same. The same type of hydraulic motor, the force of friction pair balanced design, its high and low points. For example, some gear-type hydraulic motor only about 0.6, and the high-performance low-speed high torque hydraulic motor can be achieved = 0.90, vary considerably. So, if the hydraulic motor load start, it must be noted that the start-up performance of the selected hydraulic motor. 3. Hydraulic motor speed and low-speed stability The rotational speed of the hydraulic motor vary depending on the displacement V of the liquid supply flow rate q, and the hydraulic motor itself. Since the hydraulic motor internal leakage, not all the liquid into the motor driving the hydraulic motor acting, a small portion of the liquid is lost due to leakage losses, so the actual motor speed than Ideally low. wherein the volumetric efficiency of the hydraulic motor. In engineering practice, the speed of the hydraulic motor and hydraulic pump speed, measured in units of multi-purpose r / min (r / min). When the operating speed of the hydraulic motor is too low, often to maintain not uniform speed, the unstable state of the dynamic stop, which is called creeping phenomenon. Require high-speed hydraulic motor does not exceed the to 10r/min low speed high torque hydraulic motor does not exceed speed work of 3r/min, not all of the hydraulic motor can meet the requirements of. Generally speaking, low speed - low-speed torque hydraulic motor stability than the high-speed motor as well. The large displacement of the low speed high torque motor, and thus the size is large, and not caused by too low even at low speeds the sliding speed of the friction pairs, coupled with the motor displacement, the effect of leakage is relatively small, the moment of inertia of the motor itself, , so easy to get good low-speed stability return to the main directory 4 .Speed range When the work load within a very wide range from low speed to high speed, the hydraulic motor is also required to be able to work under a large speed range, or need to be able to shift the transmission mechanism, the transmission mechanism is complicated. Hydraulic motor speed range to allow maximum speed and minimum steady speed ratio, Obviously, the wide range of speed hydraulic motor should be both good high-speed performance and a good low-speed stability.The hydraulic cylinder of the hydraulic pump output pressure can be converted to mechanical energy of the actuator, it is mainly used to output the linear motion (oscillating motion). Classification of a hydraulic cylinder Hydraulic cylinder according to the structure can be divided into three categories of the piston cylinder, piston-cylinder and swing cylinder. Piston cylinder and piston-cylinder reciprocating motion, the output thrust and speed, swing cylinder is able to swing back and forth less than 360 degrees, the output torque and angular velocity. In addition to the use of a single hydraulic cylinder can also several combination or in combination with other bodies, to complete a special function. (A) piston hydraulic cylinder Piston hydraulic cylinder is divided into a double rod and single-rod two. 1 double rod piston cylinder Double rod piston cylinder piston on both ends of a diameter equal to extend the piston rod, depending on the installation can be divided into two fixed fixed cylinder and piston rod. Figure 3-4a as shown in double-rod fixed to the cylinder tube piston cylinder. The inlet and the outlet port arranged at both ends of the cylinder, piston driven by the piston rod table moves, when the effective stroke of the piston l, the range of motion of the whole table to 3L, machine covers an area of generally applicable small machine. Table travel requires a longer, can be shown in Figure 3-4B piston rod fixed form, then the cylinder block and the table is connected to the piston rod through the bracket on the machine, the power came by the cylinder. This form of installation, the range of movement of the table is only equal to the hydraulic cylinder effectively double the stroke length l (2L), and therefore small footprint. Out of the oil port can be set in the hollow stationary - the ends of the piston rod, the oil from the piston rod and out, can also be set at both ends of the cylinder, but must use the hose connection. Due to the double pole at both ends of the piston cylinders piston rod diameter is usually equal, so it is left, the effective area of the right two chambers are equal. When the left, right cavity enter the same pressure and the same fluid flow, the hydraulic cylinder both left and right direction of thrust and speed equal to the feed of the hydraulic cylinder when the piston diameter D, the piston rod diameter d, oil chamber pressures p1 and p2, q when the input flow, the double-rod cylinder-piston thrust force F and the velocity v Where A is the effective working area of the piston.In operation, the double-rod cylinder-piston design into a piston rod is subject to a pull, and the other piston rod is unstressed, the piston rod of the hydraulic cylinder can be made thin. (B) piston-cylinder The piston-cylin