黄油是工程机械修理中常用的润滑脂，可起到润滑和密封的作用。然而不正当地使用就会造成高空作业车某些部位的不良影响，让我们看看到底高空作业车哪些部位不能涂抹黄油吧。
Butter is a grease commonly used in repair of construction machinery. It can play a role of lubrication and sealing. However, improper use will cause some parts of the aerial vehicle adverse effects, let's see what parts of the aerial vehicle can not be painted butter bar.
一、高空作业车轮胎螺母涂黄油
1. Overhead truck tires, nuts and butter.
为了容易拧紧螺母和防止锈蚀，不少修理工在轮胎的螺栓螺母上涂油。实际上这是一种错误做法。因为轮胎螺母拧紧后，螺纹间就具有自锁的特征。这是由于螺纹螺旋角小于螺纹间的当量摩擦角的缘故。给定的螺栓联接中，螺旋升角是一定值，而当量摩擦角则随螺纹间的摩擦状态而变。显然，涂油后螺纹间的当量摩擦角减小，螺栓联接的自锁性能变差。因此在轮胎的螺栓和螺母上对不要涂润滑脂或滴上润滑油。这样做，反而会使螺母松动，甚至酿成事故。
In order to easily tighten the nuts and prevent rust, many repairmen grease the bolts and nuts of the tires. In fact, this is a wrong way. Because the tyre nut is tightened, the screw thread has the characteristics of self locking. This is due to the fact that the screw angle of thread is smaller than the equivalent friction angle between threads. In a given bolted connection, the helix angle is a certain value, and the equivalent friction angle varies with the friction state between threads. Obviously, the equivalent friction angle between the threads after oil painting is reduced, and the self-locking performance of the bolt connection becomes worse. Therefore, no grease or grease should be applied to the bolts and nuts of the tire. In doing so, the nut will become loose and even cause an accident.
二、汽缸垫上涂黄油
Two. Grease the cylinder mats.
因此，有些修理工在安装汽缸垫时，就会在高空作业车汽缸垫上涂上一层黄油，认为这样可以增加柴油机的密封性。殊不知，这样做反而影响了柴油机的工作性能。汽缸垫是柴油机缸体与缸盖之间比较重要的密封件，它不但能密封汽缸内所产生的高温高压气体，而且还能密封汽缸盖和缸体内的冷却水和润滑油，所以在拆装汽缸垫时，都要特别注意它的密封质量。如果安装时在汽缸垫上涂黄油，当汽缸盖螺栓拧紧时，一部分黄油就会被挤压到汽缸水道和油道中，留在缸垫间的黄油在汽缸工作时，由于受高温影响，一部分会流人汽缸燃烧，另一部分则残留在缸体与缸盖的结合面上，使缸垫、缸盖与机体平面之间产生缝隙，高温高压燃气很容易从此处冲击汽缸垫，毁坏缸垫，成漏气。此外，黄油长时间处在高温状态下还会产生积炭，造成缸垫过早老化变质。因此安装汽缸垫时切勿涂抹黄油。
Therefore, when some repairmen install the cylinder gasket, they will put a layer of butter on the cylinder gasket of the aerial vehicle, thinking that this can increase the seal of the diesel engine. Little does it know that doing so affects the performance of the diesel engine. Cylinder gasket is the most important seal between cylinder block and cylinder head of diesel engine. It not only can seal the high temperature and high pressure gas produced in cylinder, but also can seal the cooling water and lubricating oil in cylinder head and cylinder block. Therefore, when disassembling and assembling cylinder gasket, special attention should be paid to its sealing quality. If butter is applied to the cylinder pad during installation, when the cylinder head bolt is tightened, part of the butter will be extruded into the cylinder water channel and oil channel. When the butter remaining in the cylinder pad is working, due to high temperature, part of the butter will flow to the cylinder to burn, the other part will remain on the cylinder head and the cylinder joint surface, so that the cylinder can be made. There is a gap between the gasket, cylinder head and the plane of the engine block. High temperature and high pressure gas can easily impact the gasket from here, destroy the gasket and leak. In addition, butter will generate carbon deposition at high temperature for a long time, resulting in premature aging and deterioration of cylinder mats. Therefore, do not apply butter when installing cylinder gaskets.
以上两种问题，对于某些高空作业维修人员来说可能是不经意间犯的小错误，但是如果日积月累就可能出现大的问题，希望大家能够引以为戒。
The above two problems, for some altitude maintenance personnel may be inadvertently made a small mistake, but if accumulated may be a major problem, I hope you can take warning.
