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無錫太湖學院
畢業(yè)設計(論文)
開題報告
題目: 高空作業(yè)車的液壓系統(tǒng)
信機 系 機械工程及自動化專業(yè)
學 號: 0923046
學生姓名: 貢濤
指導教師: 林承德 (職稱:教授 )
(職稱: )
2012 年 11 月
課題來源
江蘇省蘇州金龍客車有限公司
科學依據(jù)(包括課題的科學意義;國內(nèi)外研究概況、水平和發(fā)展趨勢;應用前景等)
高空作業(yè)車是用來運送工作人員和工作裝備到指定高度進行作業(yè)的特種車輛,是將高空作業(yè)裝置安裝在汽車底盤上組成的。高空作業(yè)裝置包括工作臂、回轉(zhuǎn)平臺、副車架、工作斗、液壓系統(tǒng)和操縱裝置等。現(xiàn)在的高空作業(yè)裝置具有操作平順、工作穩(wěn)定、自動調(diào)速、安全可靠等優(yōu)點,大大提高了空中作業(yè)的工作效率。高空作業(yè)車是利用汽車底盤作為行走機構(gòu),具有汽車的行駛通過性能,機動靈活,行駛速度高,可快速轉(zhuǎn)移,轉(zhuǎn)移到作業(yè)場地后能迅速投入工作,因此被越來越多的應用在工程建設、工業(yè)安裝、設備檢修、物業(yè)管理、航空、船舶、石化、電力、影視、市政、園林等許多行業(yè),是近幾年來國內(nèi)發(fā)展最快的專用汽車產(chǎn)品之一。
研究內(nèi)容
1、設計任務:高空作業(yè)車的液壓系統(tǒng)設計
2、機器用途:通用型,適用于建筑、安裝、管道鋪設等高空作業(yè)。
3、工作環(huán)境:風力六級以下,溫度-20~30 ℃,無腐蝕性極易爆易燃性氣體。
4、作業(yè)部分主要技術參數(shù)
最大作業(yè)高度: 11-12米
最大作業(yè)半徑: 5.5米
回轉(zhuǎn)角度: 360°
額定平臺載荷: 200kg
操作方式: 下操作、上操作可以任意選擇。
支腿形式/數(shù)量: H型/4
旋轉(zhuǎn)速度: 0-3r/min
兩支臂變幅時間:起臂:t≤70s
落臂:t≤6045s
支腿收放時間: 收支腿:t≤60s
放支腿:t≤60s
擬采取的研究方法、技術路線、實驗方案及可行性分析
1、回轉(zhuǎn)臺左右均可以全周回轉(zhuǎn)360°。
2、起升和旋轉(zhuǎn)可以同時互不干涉的動作。
3、垂直支腿在高空作業(yè)車非工作狀態(tài)下可以自由縮放。
4、水平支腿在高空作業(yè)車非工作狀態(tài)下可以自由的擴放支腿的支承范圍。
5、制動液壓缸可以隨時制動回轉(zhuǎn)馬達的轉(zhuǎn)動。
動作平穩(wěn)、安全可靠、操作方便、體積小、自重輕
研究計劃及預期成果
本課題金龍客車的高空作業(yè)車液壓系統(tǒng)為對象,對該車重要系統(tǒng)---液壓部分系統(tǒng)進行設計和研究,以實現(xiàn)高空作業(yè)車的工作穩(wěn)定、可靠,安全。主要研究過程如下:
1、 收集、分析、消化原始資料,了解熟悉目前高空作業(yè)車液壓系統(tǒng)的設現(xiàn)狀,控制方法,主要元器件及有關技術參數(shù)分析存在的問題。
2、 液壓系統(tǒng)設計
確定液壓系統(tǒng)方案
確定液壓系統(tǒng)控制方式
液壓元器件的選擇和有關計算
3、 繪制標準液壓系統(tǒng)工作圖
預期成果:制定出合理液壓系統(tǒng)方案以致使工作臂和支腿實現(xiàn)預定的運動,保證作業(yè)車安全可靠的運行。
特色或創(chuàng)新之處
液壓傳動與機械傳動、電氣傳動相比有以下主要優(yōu)點:
??? (1) 在同等功率情況下,液壓執(zhí)行元件體積小、重量輕、結(jié)構(gòu)緊湊。例如同功率液壓馬達的重量約只有電動機的1/6左右。
??? (2) 液壓傳動的各種元件,可根據(jù)需要方便、靈活地來布置;
??? (3) 液壓裝置工作比較平穩(wěn),由于重量輕,慣性小,反應快,液壓裝置易于實現(xiàn)快速啟動、制動和頻繁的換向;
(4) 操縱控制方便,可實現(xiàn)大范圍的無級調(diào)速(調(diào)速范圍達2000:1),它還可以在運行的過程中進行調(diào)速;
??? (5) 一般采用礦物油為工作介質(zhì),相對運動面可自行潤滑,使用壽命長;
??? (6) 容易實現(xiàn)直線運動;
??? (7) 既易實現(xiàn)機器的自動化,又易于實現(xiàn)過載保護,當采用電液聯(lián)合控制甚至計算機控制后,可實現(xiàn)大負載、高精度、遠程自動控制。
??? (8) 液壓元件實現(xiàn)了標準化、系列化、通用化,便于設計、制造和使用。
已具備的條件和尚需解決的問題
已具備的條件:電腦;相關開發(fā)軟件;部分技術資料。
尚需解決的問題:學習UG軟件;確定產(chǎn)品的結(jié)構(gòu)尺寸和技術要求;逆向設計建立三維數(shù)模;總成運動仿真校核。
指導教師意見
指導教師簽名:
年 月 日
教研室(學科組、研究所)意見
教研室主任簽名:
年 月 日
系意見
主管領導簽名:
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翻譯部分
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 cylinder's 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-cylinder is a single-acting hydraulic cylinder, its working principle is shown in Figure 3-7a shown, the plunger connected with the working parts, the cylinder is fixed on the body. When the pressure oil into the cylinder, push the plunger to drive the moving parts moving to the right, but the reverse return must rely on other external forces or weight-driven. Usually used in pairs of piston-cylinder reverse arrangement, as shown in Figure 3-7b.
When the thrust F generated on the plunger when the plunger diameter d, the the input hydraulic oil flow q, pressure p and speed v
The main features of the plunger hydraulic cylinder piston and cylinder with the requirements inside the cylinder hole without finishing even without processing. Oriented movement by the guide sleeve in the cylinder head, so it is especially suitable to the occasion of the trip is longer.
C) swing cylinder
Swing hydraulic cylinder, also known as swing hydraulic motor. When it Walter pressure oil, the spindle can be less than the output oscillating motion, and Top Jigs clamping means, the feed device, transfer device and the need to periodically feed system. Figure 3-8a shows a single-vane rotary actuators, the swing angle, up to. When the the swing cylinder oil inlet and outlet pressure p1 and p2, the input flow q, its output torque T and angular velocity of the
Formula, b is the width of the blade, R1, R2 for the bottom of the blade, at the top of the radius of gyration.
中文部分:
液壓執(zhí)行元件是將液壓泵提供的液壓能轉(zhuǎn)變?yōu)闄C械能的能量轉(zhuǎn)換裝置,它包括液壓缸和液壓馬達。液壓馬達習慣上是指輸出旋轉(zhuǎn)運動的液壓執(zhí)行元件,而把輸出直線運動(其中包括輸出擺動運動)的液壓執(zhí)行元件稱為液壓缸。
一、液壓馬達的特點及分類
從能量轉(zhuǎn)換的觀點來看,液壓泵與液壓馬達是可逆工作的液壓元件,向任何一種液壓泵輸入工作液體,都可使其變成液壓馬達工況;反之,當液壓馬達的主軸由外力矩驅(qū)動旋轉(zhuǎn)時,也可變?yōu)橐簤罕霉r。因為它們具有同樣的基本結(jié)構(gòu)要素--密閉而又可以周期變化的容積和相應的配油機構(gòu)。
但是,由于液壓馬達和液壓泵的工作條件不同,對它們的性能要求也不一樣,所以同類型的液壓馬達和液壓泵之間,仍存在許多差別。首先液壓馬達應能夠正、反轉(zhuǎn),因而要求其內(nèi)部結(jié)構(gòu)對稱;液壓馬達的轉(zhuǎn)速范圍需要足夠大,特別對它的最低穩(wěn)定轉(zhuǎn)速有一定的要求。因此,它通常都采用滾動軸承或靜壓滑動軸承;其次液壓馬達由于在輸入壓力油條件下工作,因而不必具備自吸能力,但需要一定的初始密封