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伸缩臂挖掘机性能稳定的重要因素是什么?

日期:2019-03-19   来源:http://www.dyqicheng.com/
  伸缩臂发掘机是一种多功用工程机械,作业灵敏,消费效率高,工况顺应才能强,在交通运输、水利及电力工程和矿山采掘中发挥着重要的作用,由于液压伸缩臂发掘机工况条件比拟恶劣:粉尘大、温度高、重负荷及连续作业。发起机和液压系统做工时产生较多的热量,据统计,在液压伸缩臂发掘机的毛病中,大局部毛病来至于发起机与液压系统过热。因而,牢靠的散热系统是保证伸缩臂发掘机性能稳定的重要要素。
  Telescopic boom excavator is a kind of multi-functional construction machinery, which has the characteristics of sensitive operation, high consumption efficiency and strong adaptability to working conditions. It plays an important role in transportation, water conservancy, power engineering and mining. Because the working conditions of hydraulic telescopic boom excavator are comparatively bad: large dust, high temperature, heavy load and continuous operation. Starter and hydraulic system produce more heat during working. According to statistics, most of the faults of hydraulic telescopic boom excavator come from the overheating of starter and hydraulic system. Therefore, a reliable heat dissipation system is an important factor to ensure the stable performance of telescopic boom excavator.
  2 优化设计
  2. Optimum Design
  散热系统散热量Q与冷却风流量M,散热面积A成正比,与进风温差Δt3成反比,即Q=f(M、A、Δt3),因而改善散热系统的散热性能要从这三个关键因子采取计划。
  The heat dissipation Q of the heat dissipation system is proportional to the cooling air flow M, the heat dissipation area A, and inversely proportional to the temperature difference T3 of the intake air, i.e. Q=f (M, A, t3). Therefore, the improvement of the heat dissipation performance of the heat dissipation system should be planned from these three key factors.
  2.1 增加冷却风流量
  2.1 Increase cooling air flow
  液压伸缩臂发掘机风扇优先采用低速、大直径吸风型风扇,应用外部低温空气冷却液压油和冷却水,相比高速、小直径风扇冷却效果好和噪音低。因而,风扇的叶尖处线速度不能超越4200~5000m/min,满足装置尺寸的状况下风扇直径尽量选大。
  Hydraulic telescopic boom excavator fan preferred low-speed, large diameter suction fan, external low-temperature air cooling hydraulic oil and cooling water, compared with high-speed, small diameter fan cooling effect and low noise. Therefore, the linear speed at the tip of the fan can not exceed 4200-5000m/min, and the diameter of the fan should be as large as possible when the size of the device is satisfied.
  2.1.1 风扇与导风罩的轴向重合宽度
  2.1.1 Axial coincidence width between fan and guide hood
  关于吸风型风扇来说,普通取风扇叶投影宽度的2/3宽度被导风罩罩住,此时能到达大吸风效率,另外,导风罩和散热器须密封紧密,保证冷却风不流失。
  For suction fans, the projection width of the common fan blade is 2/3 of the width of the hood, which can achieve high suction efficiency. In addition, the hood and radiator must be tightly sealed to ensure that the cooling air does not lose.
  2.1.2 风扇与导风罩的径向间隙
  2.1.2 Radial Clearance between Fan and Guide Hood
  理论上风扇与导风罩径向间隙越小,风扇旋转时惹起的内外压力差越大,吸风量越大,但由于伸缩臂发掘机工况条件比拟恶劣,机身的振动可能惹起风扇与导风罩的干预,因而理想间隙应设定为风扇直径的1.5~2.5,当间隙大于这个范围时2.5时,吸风量会剧减。
  Theoretically, the smaller the radial clearance between the fan and the guide hood, the greater the difference of internal and external pressure caused by the fan rotation, and the larger the suction capacity. However, due to the poor working conditions of the telescopic boom excavator, the vibration of the fuselage may cause the interference between the fan and the guide hood. Therefore, the ideal clearance should be set at 1.5-2.5 of the fan diameter. When the clearance is larger than this range, the suction capacity will decrease dramatically.
  2.1.3 风扇与散热器芯子的轴向间隔
  2.1.3 Axial Spacing between Fan and Radiator Core
  依据各元素剖析办法的请求及实验室的仪器设备状况,制定了以下剖析办法配套计划:原子荧光光谱法(AFS)检测As、Sb、Bi;ICP-OES检测Cu、Zn、Co、Ni、Cr;示波极谱法(POL)检测W、Mo;光谱深孔电极法(AES)检测Ag、Sn、Pb;石墨炉检测Au。
  According to the requirements of each element analysis method and the status of laboratory instruments and equipment, the following supporting plans for analysis methods were formulated: atomic fluorescence spectrometry (AFS) for the detection of As, Sb and Bi; ICP-OES for the detection of Cu, Zn, Co, Ni and Cr; oscillopolarography (POL) for the detection of W, Mo; spectroscopic deep hole electrode (AES) for the detection of Ag, Sn and Pb; graphite furnace for the detection of Au.
  2.1.4 出风口位置的选择
  Selection of 2.1.4 Outlet Location
  冷风完成热交流以后需求选择合理的出风口位置,出风要畅通,确保发起机室风压不能障碍冷却风进风速度,保证流经散热器的冷却风流量为合理值。如图2所示的上下同时出风的方式,热交流后的热风可顺畅的排出,有效的防止发起机室内的“窝风”现象。同时为了降低泵室的温度,在发起机室和泵室之间开通风口孔,使却风能同时流经泵室,进步散热效果。  2.4 降低液压系统背压
加长臂挖掘机出租
  After the cold air completes the heat exchange, it is necessary to choose a reasonable outlet position, and the outlet should be smooth, so as to ensure that the air pressure in the engine room can not obstruct the cooling air inlet speed, and ensure the cooling air flow through the radiator to be a reasonable value. As shown in Figure 2, the hot air can be discharged smoothly after heat exchange, effectively preventing the phenomenon of "nest wind" in the engine room. At the same time, in order to reduce the temperature of the pump room, the vent hole is opened between the engine room and the pump room, so that the wind energy flows through the pump room at the same time, so as to improve the heat dissipation effect. 2.4 Reducing Back Pressure of Hydraulic System
  伸缩臂发掘机散热系统有水散和油散两局部,水散系统采用节温器自动控制流经散热器的冷却水流量,使发起机坚持在工作温度。油散系统中液压油流量与系统背压有直接关系。液压系统背压越高,流经散热器的油量会越小,热交流量减小,油温升高,可经过几个措施降低系统背压。
  The heat dissipation system of telescopic boom excavator has two parts: water and oil. The water dissipation system uses thermostat to automatically control the cooling water flow through the radiator, so that the starter keeps working temperature. There is a direct relationship between hydraulic oil flow rate and system back pressure in oil dispersion system. The higher the back pressure of the hydraulic system is, the smaller the amount of oil flowing through the radiator will be, the less the heat exchange will be, and the higher the oil temperature will be. Several measures can be taken to reduce the back pressure of the system.
  ①在满足回转马达不吸空的前提下,将油路背压阀的开启压力降到小值;②降低散热器本身压损,减小回油过滤器的压力损失;③液压油箱采用侧面回油方式,减小回油阻力。
  On the premise that the rotary motor does not absorb air, the opening pressure of the back pressure valve of the oil circuit is reduced to a small value; the pressure loss of the radiator itself is reduced, and the pressure loss of the oil return filter is reduced; and the side oil return mode is adopted in the hydraulic tank to reduce the oil return resistance.
  散热器良好的散热效果可保证伸缩臂发掘机在高温、高湿和高尘等恶劣工况下工作稳定性,本文剖析了影响散热器散热效果的关键要素,并从多个方面提出优化设计计划。为进步散热系统的散热性能提供参考。
  The good heat dissipation effect of the radiator can ensure the stability of the telescopic boom excavator under the harsh conditions of high temperature, high humidity and high dust. This paper analyses the key factors affecting the heat dissipation effect of the radiator, and puts forward the optimal design plan from many aspects. It provides a reference for improving the heat dissipation performance of heat dissipation system.

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