As a very important construction machinery in today's construction engineering, many diggers also pay great attention to its maintenance work. However, many diggers do not know the wrong maintenance work will have a negative impact on the performance of their extended arm excavators. Today, Tongda Machinery will explain the ten taboos of the maintenance of extended arm excavators.
Extended arm excavator
Myth 1: Oil is added but not replaced
Many diggers pay attention to check the remaining oil of lubricating oil and add it according to the standard, but ignore the inspection of the quality of lubricating oil and the removal of the already mildewed oil, resulting in many engine moving parts have been running in poor lubrication environment, thus speeding up the damage of parts.
Myth 2: Misuse of butter
Butter is a common grease in the maintenance of construction machinery, which has the function of lubrication and sealing. Therefore, when some assemblers install the cylinder gasket, they will coat the cylinder gasket with butter, thinking that it can improve the tightness of the diesel engine. It is unknown that doing so would endanger the working performance of diesel engines.
Mistake 3: Installation of new cylinder liner and piston products without selection在换装气缸套和活塞杆时，觉得新的气缸套和活塞杆全是紧固件，都具备互换性，装上就可以使用了。事实上，气缸套与活塞杆的规格常有一定的尺寸公差范畴，如把较大规格的气缸套加上最小尺寸的活塞杆，会使相互配合空隙过大，导致压缩无力，起动艰难。
When replacing the cylinder liner and piston rod, the new cylinder liner and piston rod are all fasteners, which are interchangeable and can be used. In fact, the specifications of cylinder liner and piston rod often have certain dimension tolerances. If the larger cylinder liner is added with the smallest piston rod, the mating gap will be too large, resulting in weak compression and difficult starting.
Mistake 4: inaccurate measurement of cylinder clearance在精确测量汽缸空隙时，无法在活塞裙部垂直平分活塞销孔的方位测量，而在其他方向测量。铝合金型材活塞的构造特性是上小下大，为一锥体，且裙部断面为椭圆形，所以沿圆周方向的汽缸空隙并不是相等。
When measuring cylinder clearance accurately, it is impossible to measure the azimuth of piston pinhole vertically and equally in piston skirt, but in other directions. The piston of aluminium alloy profile is a cone with small top and large bottom, and the skirt section is elliptical, so the cylinder voids along the circumference direction are not equal.
Myth 5: Piston open fire heating
Because the piston rod and the piston pin are interference, when installing the piston pin, the piston should be heated and expanded first. At this time, some maintenance staff will put the piston rod on the open fire to heat directly. When the piston pin is reinstalled, the piston can be heated symmetrically in hot oil to slow down expansion. Do not immediately heat the piston with open fire.
Myth 6: Grinding Bearing with Abrasive Cloth许多人在拆换轴瓦时，为扩大活塞销与传动轴的触碰面积，就用砂纸打磨抛光以替代刮瓦。这类方式在具体维修中是极不可用的，由于砂纸上的磨粒偏硬，而活塞销铝合金却过软，那样在打磨抛光时沙粒很非常容易置入合金内，柴油机工作中时会加快轴颈的损坏，减少传动轴的使用期。
In order to expand the contact area between the piston pin and the transmission shaft, many people use sandpaper to polish the bearing bush instead of scraping. This kind of method is extremely unavailable in the specific maintenance. Because the abrasive particles on sandpaper are hard and the piston pin aluminum alloy is too soft, the sand particles are very easy to be put into the alloy when polishing. When the diesel engine works, the damage of the journal will be accelerated and the service life of the transmission shaft will be reduced.
Myth 7: Too tightly screwed bolts
In the process of disassembly, many positions of bolts are all required by the torque, such as gear, cylinder head, wheel ring, crankshaft and front axle assembly, etc. The tightening torque has professional requirements in the instructions for use, and should not be changed arbitrarily. However, many users mistakenly believe that tightening something is safer, but tightening too tightly will cause the breakage of screw or foot screw, or may cause system failure due to loosening of thread.
Myth 8: Suddenly add cold water to the pot柴油发动机过载作业、热管散热不太好或水箱少水都是造成水箱开锅，这时假如马上添加冷水，就会造成缸盖和缸体炸裂。因而，应用中如果发现水箱开锅，应采用紧急措施终止作业，使柴油机冷却循环水自主减温。
Overload operation of diesel engine, poor heat dissipation of heat pipe or lack of water in water tank all cause the water tank to boil. If cold water is added immediately, the cylinder head and cylinder block will burst. Therefore, if it is found that the water tank is boiling in the application, emergency measures should be taken to stop the operation, so that the cooling circulating water of diesel engine can be self-cooling.