1816_調(diào)速器前殼加工工藝與工裝設(shè)計

1816_調(diào)速器前殼加工工藝與工裝設(shè)計,調(diào)速器,加工,工藝,工裝,設(shè)計 調(diào)速器Governor調(diào)速器的作用是將內(nèi)燃機(jī)的轉(zhuǎn)速限制在一定范圍內(nèi)。運(yùn)行時，柴油機(jī)所帶的負(fù)載是不斷變化的。在負(fù)載變化時，特別是突然變化時，必須保持柴油機(jī)的轉(zhuǎn)速穩(wěn)定，不得出現(xiàn)停車或飛車事故。調(diào)速器就是自動保持轉(zhuǎn)速穩(wěn)定的裝置。對于發(fā)電用的柴油機(jī)，要求其轉(zhuǎn)速基本恒定在同步轉(zhuǎn)速，對調(diào)速器的調(diào)速特性要求很高。 內(nèi)燃機(jī)工作時，如內(nèi)燃機(jī)的輸出轉(zhuǎn)矩與外界的阻力矩(負(fù)載)相等時，工作才能穩(wěn)定。如阻力矩超過內(nèi)燃機(jī)的轉(zhuǎn)矩時，轉(zhuǎn)速將降低;反之則升高。為使工作機(jī)械穩(wěn)定地工作，就必須隨著阻力的變化相應(yīng)調(diào)節(jié)供油量，使發(fā)動機(jī)的轉(zhuǎn)矩與外界負(fù)載相適應(yīng)。由柴油機(jī)的速度特性可以看出，柴油機(jī)的轉(zhuǎn)矩 Me=f(n)曲線比較平坦。在柴油機(jī)運(yùn)轉(zhuǎn)時，如油量調(diào)節(jié)桿固定在某一位置，柴油機(jī)的轉(zhuǎn)矩 Me 就按速度特性變化，而外界負(fù)載是經(jīng)常變化的。如推土機(jī)在干濕不同、軟硬不一的土壤中作業(yè)時，阻力矩就有明顯的變化。如阻力矩有較小的變化(△M)，將引起轉(zhuǎn)速較大的變化( △n) ，柴油機(jī)的工作是不穩(wěn)定的。如要人為的控制供油量來適應(yīng)外界負(fù)載的變化，這不僅使司機(jī)疲勞，而且也難以保持轉(zhuǎn)速的穩(wěn)定。 調(diào)速器屬于自動調(diào)節(jié)裝置。當(dāng)外界負(fù)載變化時，它能隨著負(fù)載的變化自動調(diào)節(jié)供油量，使柴油機(jī)的轉(zhuǎn)速穩(wěn)定在一定的轉(zhuǎn)速范圍內(nèi)。 汽車或工程機(jī)械是經(jīng)常在負(fù)載不斷變化的情況下工作的，而且還會遇到負(fù)載突變的情況。如推土機(jī)作業(yè)時，當(dāng)卸土以后，由于突然卸去了負(fù)載，噴油泵油量調(diào)節(jié)桿一時還來不及向減少供油量的方向移動，柴油機(jī)的轉(zhuǎn)速就會迅速升高，而這時由于噴油泵速度特性的作用，噴油泵的循環(huán)供油量反而增大，促使柴油機(jī)的轉(zhuǎn)速進(jìn)一步升高。這樣相互影響的結(jié)果，便柴油機(jī)的轉(zhuǎn)速越來越高，嚴(yán)重時會出現(xiàn)超速，甚至發(fā)生" 飛車"事故，以致引起機(jī)件損壞。 另外，柴油機(jī)還經(jīng)常遇到低速空轉(zhuǎn)(怠速) 的場合，如短暫停車、起動暖車、變速器換擋等。柴油機(jī)在怠速運(yùn)轉(zhuǎn)時只供給很少量的燃油，這部分燃油發(fā)出的能量只能克服發(fā)動機(jī)內(nèi)部的摩擦阻力，這時發(fā)動機(jī)工作的穩(wěn)定性主要取決于其內(nèi)部摩擦阻力的變化和氣缸內(nèi)氣體做功變化的相互關(guān)系。這兩者可用平均機(jī)械損失壓力 Pm 和平均指示壓力 Pi 的變化來表示。一般發(fā)動機(jī)隨轉(zhuǎn)速的增加，平均機(jī)械損失壓力 Pm都略有增加。為了使怠速運(yùn)轉(zhuǎn)穩(wěn)定，必須在轉(zhuǎn)速升高時，使平均指示壓力 Pi 減小，而在轉(zhuǎn)速降低時使其增大。柴油機(jī)怠速運(yùn)轉(zhuǎn)時，油量調(diào)節(jié)桿保持在最小供油量位置，這時如果某種原因(如潤滑油粘度的變化) 使柴油機(jī)的內(nèi)部阻力略有增大，則其轉(zhuǎn)速就略為降低，但由于噴油泵速度特性的作用，每循環(huán)供油量反而減少，這就促使轉(zhuǎn)速迸一步降低，如此循環(huán)作用，最后將使柴油機(jī)熄火;反之，如柴油機(jī)內(nèi)部的阻力略有減小，則將導(dǎo)致柴油機(jī)怠速轉(zhuǎn)速不斷升高，所以柴油機(jī)的怠速是很不穩(wěn)定的。因此，汽車柴油機(jī)通常裝用兩極式調(diào)速器來達(dá)到防止超速和穩(wěn)定怠速的目的。 調(diào)速器的作用即在于改變 Pi 曲線的變化歷程，使 Pi 曲線隨轉(zhuǎn)速升高而急劇下降。這樣在怠速時能保持穩(wěn)定，在高速時能防止超速。 在某些工作條件比較特殊的柴油機(jī)上，如工作時負(fù)載變化急劇的工程機(jī)械以及工作條件要求在負(fù)載改變后轉(zhuǎn)速保持一定范圍的柴油機(jī)(如帶發(fā)電機(jī)、空壓機(jī)、水泵等)，則要求采用全程式調(diào)速器，這種調(diào)速器不僅能防止超速和保持怠速的穩(wěn)定性，而且還能自動控制任何所要求的速度工況。全程式調(diào)速器還可以減輕司機(jī)操作，提高柴油機(jī)的使用經(jīng)濟(jì)性和勞動生產(chǎn)率。 2.柱塞式噴油泵的速度特性。噴油泵的循環(huán)供油量主要取決于油量調(diào)節(jié)桿( 拉桿或齒桿)的位置。但是，在實際上供油量還受到柴油機(jī)轉(zhuǎn)速的影響。 當(dāng)油量調(diào)節(jié)桿位置定時，噴油泵的循環(huán)供油量隨轉(zhuǎn)速變化的關(guān)系，稱為噴油泵的速度特性。它對柴油機(jī)的工作有很大的影響。GovernorThe role of governor is to limit the engine speed within a certain range. Running, engine load is carried by the ever-changing. When the load changes, especially sudden changes, the need to maintain the engine speed stability, with no parking or coaster accident. Governor is a device that automatically maintains speed stability. Diesel engines for power generation, asking them to speed almost constant in the synchronous speed, the speed characteristics of the governor demanding. Internal combustion engines work, such as the internal combustion engine output torque and the external resistance moment (load) are equal, working to stabilize. Such as the drag torque than internal combustion engine torque, the speed will be reduced; otherwise increased. Mechanical stability for the work to work, to be adjusted accordingly with the change of resistance of fuel supply, engine torque load with the outside world to adapt. The speed of the engine characteristics can be seen, the engine torque Me = f (n) curve is flat. In the diesel engine operation, such as the oil lever in a fixed position, engine speed torque characteristics by Me to change, while the external load is constantly changing. Such as bulldozers in the different wet and dry, hard and soft soil in different operations, there are significant changes in resistance torque. If there are small changes in resistance torque (△ M), will cause a large speed change (△ n), the diesel engine was unstable. To control the fuel supply to artificially adapt to load changes, which not only allows the driver fatigue, but also difficult to maintain speed and stability. Governor of automatic adjustment device. When the external load changes, it can automatically adjust with the change of the load amount of oil that the engine speed steady at a certain speed range. Vehicle or machinery is often the case load changing work, but also the situation encountered mutation load. Such as the bulldozer operation, when the dump, because of the sudden load lifted, fuel injection pump lever for a moment too late to move to reduce the amount of oil, the engine speed will rapidly increase, and then the fuel pump The role of velocity characteristics, but the amount of fuel injection pump oil increases circulation to promote the engine speed further increases. The results of this interaction, increasing the engine speed will be high speed in severe cases, or even "speed" accident, resulting in mechanical damage. In addition, low-speed diesel engine idling also frequently encountered (idle) of occasions, such as short-term parking, starting warm up, gear shift and so on. Diesel engine running at idle only a small amount of fuel supply, this part of the fuel energy can only be issued by the friction inside the engine to overcome, then the stability of the engine depends largely on the work of the internal friction changes and changes in cylinder acting relationship. These two losses can mean mechanical pressure Pm and the average indicated pressure Pi of the changes said. General engine with engine speed increases, the mean pressure Pm mechanical losses are slightly increased. In order to idle stability to speed increases, the mean indicated pressure Pi decreases, while it increases when the speed is reduced. Diesel engine idling, fuel lever position to a minimum fuel supply, then if for some reason (such as changes in lubricant viscosity) the engine's internal resistance increases slightly, its speed to slightly lower, but The role of the pump velocity characteristic, however, reduced amount of oil per cycle, which led into further reduce the speed, so cycles, the final engine will turn off; the other hand, such as diesel internal resistance decreases slightly, it will lead to engine Idle speed constantly increases, so the engine idle speed is very unstable. Therefore, the car engine is usually equipped with bipolar prevent the governor to achieve the purpose of speeding and idling stability. The role of governor is to change the course of Pi curves, so that Pi curve rises sharply with speed. This can keep the idle stable at high speed to prevent speeding. Comparison of working conditions in certain special diesel engines, such as rapid changes in work load and working conditions of construction machinery after the change in load required to maintain a certain range of engine speed (such as generator, air compressor, water pump, etc.), they are required governor with the whole program, this governor can not only prevent the idle speed and maintain stability, but also to automatically control the speed of any of the required conditions. All programs can also reduce drivers speed governor action to improve the use of diesel economy and labor productivity. 2. Plunger injection pump speed characteristics. Circulation pump depends on the amount of fuel oil adjustment lever (lever or gear lever) position. However, in practice fuel supply but also by the impact of engine speed. Lever position when the fuel timing, fuel injection pump fuel delivery cycle of the relationship with the speed changes, called the fuel pump speed characteristics. The work of its diesel engine has a great influence.