1．對潤滑系統(tǒng)的要求是為所有的齒輪、軸承和花鍵提供潤滑和冷卻。它應(yīng)當(dāng)能夠收集外來物，因為如果留在軸承機匣或齒輪箱內(nèi)，就會造成迅速的損壞。而且，滑油應(yīng)當(dāng)防護由非耐腐蝕材料制成的被滑潤的部件。滑油應(yīng)當(dāng)完成這些任務(wù)而不致嚴(yán)重變質(zhì)。
第八章 潤滑
潤滑系統(tǒng)
4．共有兩種基本的循環(huán)系統(tǒng)，即“減壓活門”系統(tǒng)和“全流量”系統(tǒng)。它們的主要差別在于對供向軸承的滑油流量的控制。在這兩種系統(tǒng)中對于發(fā)動機正確和安全運轉(zhuǎn)最關(guān)鍵的是滑油的溫度和壓力。因此，在駕駛艙中有用于指示這些參數(shù)的設(shè)備。
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.
減壓活門系統(tǒng)
5．在減壓活門系統(tǒng)中，通過將供油路中的滑油壓力限制到給定的設(shè)計值來控制向軸承腔供應(yīng)的滑油流量。在設(shè)計上采用了彈簧加載的活門，當(dāng)超過設(shè)計值時，它允許滑油從增壓泵出口或增壓泵進口直接返回滑油箱。
在相當(dāng)于發(fā)動機慢車轉(zhuǎn)速的壓力下，該活門打開，因此，在所有發(fā)動機正常工作轉(zhuǎn)速下，它都提供恒定的供油壓力。但是，增大發(fā)動機轉(zhuǎn)速會使軸承腔壓力急劇增加。這會降低軸承腔和供油噴嘴之間的壓力差，從而隨著發(fā)動機轉(zhuǎn)速的增加而減少向軸承的供油流量。為了緩解這個問題，某些減壓活門系統(tǒng)利用正在增大的軸承腔壓力來加大減壓活門的彈簧載荷。這樣，通過隨軸承腔壓力增大而增大供油路中的壓力來保持在更高發(fā)動機轉(zhuǎn)速下恒定的滑油流量
6．圖8-1示出，渦輪螺槳發(fā)動機的減壓活門系統(tǒng)，并指出了發(fā)動機潤滑系統(tǒng)所包含的基本部件。滑油增壓泵自油箱抽油，中間經(jīng)過一個濾網(wǎng)，該濾網(wǎng)保護油泵的齒輪，不讓可能進入油箱的碎片進入油泵。然后，滑油通過高壓油濾進入減壓活門，保持對軸承腔中的供油噴嘴的供油壓力恒定。某些發(fā)動機可能有另外的減壓活門(壓力限制活門)裝在滑油增壓泵的出口。該活門設(shè)定打開的壓力值要比減壓活門的壓力值高很多，它在系統(tǒng)發(fā)生堵塞時將滑油返回滑油增壓泵的進口。類似的活門也可以裝在跨越壓力油濾的旁路中用來防止軸承腔缺油。在萬一油濾發(fā)生部分堵塞，或者在冷天起動條件下滑油粘度高，妨礙足夠流量的滑油流過油濾時，這種缺油現(xiàn)象就會出現(xiàn)。還有一些設(shè)備將滑油送往螺旋槳槳距控制系統(tǒng)，減速齒輪和扭矩計系統(tǒng)。回油泵將滑油經(jīng)過滑油散熱器送回滑油箱。在進入油箱時，滑油已經(jīng)過油氣分離，可以再次進行循環(huán)。
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. 高壓油濾
減壓活門
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 中國航空網(wǎng) www.k6050.com 航空翻譯 www.aviation.cn 本文鏈接地址：勞斯萊斯噴氣引擎－中英(36)
