1．对润滑系统的要求是为所有的齿轮、轴承和花键提供润滑和冷却。它应当能够收集外来物，因为如果留在轴承机匣或齿轮箱内，就会造成迅速的损坏。而且，滑油应当防护由非耐腐蚀材料制成的被滑润的部件。滑油应当完成这些任务而不致严重变质。
第八章 润滑
润滑系统
4．共有两种基本的循环系统，即“减压活门”系统和“全流量”系统。它们的主要差别在于对供向轴承的滑油流量的控制。在这两种系统中对于发动机正确和安全运转最关键的是滑油的温度和压力。因此，在驾驶舱中有用于指示这些参数的设备。
INTRODUCTION
1. The lubrication system is required to provide lubrication and cooling for all gears, bearings and splines. It must also be capable of collecting foreign matter which, if left in a bearing housing or gearbox, can cause rapid failure. Additionally, the oil must protect the lubricated components which are manu-factured from non-corrosion resistant materials. The oil must accomplish these tasks without significant deterioration.
heavily loaded propeller reduction gears and the need for a high pressure oil supply to operate the propeller pitch control mechanism.
3. Most gas turbine engines use a self-contained recirculatory lubrication system in which the oil is distributed around the engine and returned to the oil tank by pumps. However, some engines use a system known as the total loss or expendable system in which the oil is spilled overboard after the engine has been lubricated.
LUBRICATING SYSTEMS
4. There are two basic recirculatory systems, known as the 'pressure relief valve1 system and the 'full flow' system. The major difference between them is in the control of the oil flow to the bearings. In both systems the temperature and pressure of the oil are critical to the correct and safe running of the engine. Provision is therefore made for these parameters to be indicated in the cockpit.
减压活门系统
5．在减压活门系统中，通过将供油路中的滑油压力限制到给定的设计值来控制向轴承腔供应的滑油流量。在设计上采用了弹簧加载的活门，当超过设计值时，它允许滑油从增压泵出口或增压泵进口直接返回滑油箱。
在相当于发动机慢车转速的压力下，该活门打开，因此，在所有发动机正常工作转速下，它都提供恒定的供油压力。但是，增大发动机转速会使轴承腔压力急剧增加。这会降低轴承腔和供油喷嘴之间的压力差，从而随着发动机转速的增加而减少向轴承的供油流量。为了缓解这个问题，某些减压活门系统利用正在增大的轴承腔压力来加大减压活门的弹簧载荷。这样，通过随轴承腔压力增大而增大供油路中的压力来保持在更高发动机转速下恒定的滑油流量
6．图8-1示出，涡轮螺桨发动机的减压活门系统，并指出了发动机润滑系统所包含的基本部件。滑油增压泵自油箱抽油，中间经过一个滤网，该滤网保护油泵的齿轮，不让可能进入油箱的碎片进入油泵。然后，滑油通过高压油滤进入减压活门，保持对轴承腔中的供油喷嘴的供油压力恒定。某些发动机可能有另外的减压活门(压力限制活门)装在滑油增压泵的出口。该活门设定打开的压力值要比减压活门的压力值高很多，它在系统发生堵塞时将滑油返回滑油增压泵的进口。类似的活门也可以装在跨越压力油滤的旁路中用来防止轴承腔缺油。在万一油滤发生部分堵塞，或者在冷天起动条件下滑油粘度高，妨碍足够流量的滑油流过油滤时，这种缺油现象就会出现。还有一些设备将滑油送往螺旋桨桨距控制系统，减速齿轮和扭矩计系统。回油泵将滑油经过滑油散热器送回滑油箱。在进入油箱时，滑油已经过油气分离，可以再次进行循环。
Lubrication
Pressure relief valve system
5. In the pressure relief valve system the oil flow to the bearing chambers is controlled by limiting the pressure in the feed line to a given design value. This is accomplished by the use of a spring loaded valve which allows oil to be directly returned from the pressure pump outlet to the oil tank, or pressure pump inlet, when the design value is exceeded. The valve opens at a pressure which corresponds to the idling speed of the engine, thus giving a constant feed pressure over normal engine operating speeds. However, increasing engine speed causes the bearing chamber pressure to rise sharply. This reduces the pressure difference between the bearing chamber and feed jet, thus decreasing the oil flow rate to the bearings as engine speed increases. To alleviate this problem, some pressure relief valve systems use the increasing bearing chamber pressure to augment the relief valve spring load, This maintains a constant flow rate at the higher engine speeds by increasing the pressure in the feed line as the bearing chamber pressure increases. 高压油滤
减压活门
6 Fig. 8-1 shows the pressure relief valve system for a turbo-propeller engine and indicates the basic components that comprise an engine lubrication system. The oil pressure pump draws oil from the tank through a strainer which protects the pump gears from debris which may have entered the tank, Oil is then delivered through a pressure filter to the pressure relief valve which maintains a constant oil delivery pressure to the feed jets in the bearing chambers. Some engines may have an additional relief valve (pressure limiting valve) which is fitted at the oil pressure pump outlet. This valve is set to open at a much higher value than the pressure relief valve to return the oil to the inlet side of the oil pressure pump in the event of the system becoming blocked. A similar valve may also be fitted across the pressure filter to prevent oil starvation of the bearing chambers should the filter become partially blocked or the oil having a high viscosity under cold starting conditions preventing sufficient flow through the filter. Provision is also made to supply oil to the propeller pitch control system, reduction gear and torquemeter 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：劳斯莱斯喷气引擎－中英(36)
