單片干式中央彈簧汽車離合器設(shè)計(jì)
單片干式中央彈簧汽車離合器設(shè)計(jì),單片干式中央彈簧汽車離合器設(shè)計(jì),單片,中央,彈簧,汽車,離合器,設(shè)計(jì)
附 錄
How Does the Clutch Work
The clutch is a device to engage and disengage power from the engine, allowing the vehicle to stop and start.
A pressure plate or “driving member” is bolted to the engine flywheel, and a clutch plate or “driven member” is located between the flywheel and the pressure plate. The clutch plate is spline to the shaft extending from the transmission to the flywheel, commonly called a clutch shaft or input shaft. When the clutch and pressure plates are locked together by friction, the clutch shaft rotates with the engine crankshaft. Power is transferred from the engine to the transmission, where it is routed through different gear rations to obtain the best speed and power to start and keep the vehicle moving.
The flywheel is located at the rear of the engine and is bolted to the crankshaft. It helps absorb power impulses, resulting in a smoothly-idling engine and provides momentum to carry the engine through its operating cycle. The rear surface of the flywheel is machined flat and the clutch components are attached to it. The driving member is commonly called the pressure plate. It is bolted to the engine flywheel and its main purpose is to exert pressure against the clutch plate, holding the plate tight against the flywheel and allowing the power to flow from the engine to the transmission. It must also be capable of interrupting the power flow by releasing the pressure on the clutch plate. This allows the clutch plate to stop rotating while the flywheel and pressure plate continues to rotate.
The pressure plate consist of a heavy metal plate, coil springs or diaphragm spring, release levers (fingers), and a cover. When coil springs are used, they are evenly spaced around the metal plate and located between the plate and the metal cover. This places an even pressure against the plate, which in turn presses the clutch plate tight against the flywheel. The cover is bolted tightly to the flywheel and the metal pate is movable, due to internal linkages. The coil springs are arranged to exert direct or indirect tension on the metal plate, depending upon the manufacturer’s design. Three release levers (fingers), evenly spaced around the cover, are used on most pressure plates to release the holding pressure of the springs on the clutch plate, allowing it to disengage the power flow.
When a diaphragm spring is used instead of coil springs, the internal linkage is necessarily different to provide an “over-center” action to release the clutch plate from the flywheel. Its operation can be compared to the operation of an oilcan. When depressing the slightly curved metal on the bottom of the oilcan, it goes over-center and gives out a loud “clicking” noise; when released, the noise is again heard as the metal returns to its original position. A click is not heard in the clutch operation, but the action of the diaphragm spring is the same as the oilcan.
The clutch plate or driven member consists of a round metal plate attached to a splined hub. The outer portion of the round plate is covered with a friction material of molded or woven asbestos and is riveted or bonded to the plate. The thickness of the clutch plate and /or facings may be warped to give a softer clutch engagement. Coil springs are often installed in the hub to help provide a cushion against the twisting force of engagement. The splined hub is mated to (and turns) a splined transmission shaft when the clutch is engaged.
The release (throw out) bearing is usually a ball bearing unit, mounted on a sleeve, and attached to the release or throw out lever. Its purpose is to apply pressure to the diaphragm spring or release levers in the pressure plate. When the clutch pedal is depressed, the pressure of the release bearing or lever actuates the internal linkages of the pressure plate, releasing the clutch plate and interrupting the power flow. The release bearing is not in constant contract with the pressure plate. A linkage adjustment clearance should be maintained.
The clutch pedal provides mechanical means for the driver to control the engagement and disengagement of the clutch. The pedal is connected mechanically to either a cable or rods, which are directly connected to the release bearing lever.
When the clutch pedal is depressed, the linkage moves the release bearing lever. The release lever is attached at the opposite end to a release bearing which straddles the transmission clutch shaft, and presses inward on the pressure plate gingers or the diaphragm spring. This inward pressure acts upon the fingers and internal linkage of the pressure plate and allows the clutch plate to move away from the flywheel, interrupting the flow of power.
While the clutch pedal is depressed and the power flow interrupted, the transmission can be shifted in to any gear. The clutch pedal is slowly released to gradually move the clutch pate toward the flywheels under pressure of the pressure plate springs. The friction between the clutch plate and flywheel becomes greater as the pedal is released and the engine speed increased. Once the vehicle is moving, the need for clutch slippage is lessened, and the clutch pedal can be fully released.
Coordination between the clutch pedal and accelerator is important to avoid engine stalling, shock to the driveline components and excessive clutch slippage and overheating.
離合器如何工作
離合器是傳遞和分離發(fā)動(dòng)機(jī)動(dòng)力的裝置,實(shí)現(xiàn)車輛的停車和啟動(dòng)。
壓盤也就是主動(dòng)部分,用螺栓連接到發(fā)動(dòng)機(jī)飛輪上,從動(dòng)盤也就是從動(dòng)部分,位于飛輪和壓盤之間。從動(dòng)盤花鍵連接到變速器與飛輪之間的軸上,這段軸一般稱作離合器軸或者變速器輸入軸。當(dāng)離合器主動(dòng)部分和壓盤被摩擦力鎖定到一起時(shí),離合器軸與發(fā)動(dòng)機(jī)曲軸一起旋轉(zhuǎn)。動(dòng)力從發(fā)動(dòng)機(jī)傳出,傳到變速器上,在這里動(dòng)力通過不同的齒輪傳動(dòng)比獲得起車或繼續(xù)前行的最佳速度和動(dòng)力。
飛輪位于發(fā)動(dòng)機(jī)的邊上,并用螺栓連接到曲軸上。它有助于吸收發(fā)動(dòng)機(jī)的動(dòng)力沖量,保證發(fā)動(dòng)機(jī)平穩(wěn)旋轉(zhuǎn),并在運(yùn)轉(zhuǎn)循環(huán)過程中提供動(dòng)量帶動(dòng)發(fā)動(dòng)機(jī)。飛輪的背面加工成平面,離合器組件結(jié)合在上邊。
離合器主動(dòng)件通常被稱作壓盤。它螺栓連接到發(fā)動(dòng)機(jī)飛輪上,主要目的是在離合器片上施加壓力,使離合器片緊緊接觸在飛輪上,以保證動(dòng)力從發(fā)動(dòng)機(jī)傳送到變速器,離合器片上的壓力撤銷時(shí),離合器需能夠切斷動(dòng)力的傳輸。這就意味著在飛輪和壓盤保持旋轉(zhuǎn)的時(shí)候,離合器片卻能停止轉(zhuǎn)動(dòng)。
主動(dòng)部分由一個(gè)較重的金屬,螺旋彈簧或者膜片彈簧,分離杠桿(分離指)和離合器蓋組成。
當(dāng)使用螺旋彈簧時(shí),彈簧位于壓盤與金屬殼之間,均勻的分布在金屬壓盤周圍。這就給壓盤提供了一個(gè)均勻的壓緊力,壓盤又將離合器片緊緊地壓緊在飛輪上。離合器殼用螺栓緊緊地連接在飛輪上,由于內(nèi)在的連接,壓盤可以軸向移動(dòng)。均勻分布的螺旋彈簧給壓盤提供直接過間接地壓力,這取決于生產(chǎn)廠家的設(shè)計(jì)。大部分離合器壓盤有三個(gè)均勻分布在離合器殼周圍的分離杠桿(分離指),分離杠桿用來(lái)解除彈簧施加在離合器片上的壓緊力,從而切斷動(dòng)力的傳輸。
當(dāng)用膜片彈簧代替螺旋彈簧時(shí),內(nèi)部連接是截然不同的,它提供一個(gè)通過中心的動(dòng)作來(lái)時(shí)離合器片與飛輪分離。它的運(yùn)作可以比喻成油罐的動(dòng)作。當(dāng)壓下罐子底部的輕微彎曲金屬時(shí),金屬就彈到中心的另一側(cè),并且發(fā)出很大的聲音,當(dāng)放松時(shí),金屬恢復(fù)到最初的位置,同樣伴隨著很大的聲音。在離合器運(yùn)作時(shí),并聽不到敲擊的聲音,但膜片彈簧的動(dòng)作和油罐的動(dòng)作是相同的。
離合器片或者從動(dòng)部分由連接在花鍵轂上的圓形金屬片構(gòu)成。金屬圓片的外部覆蓋著摩擦材料,這些摩擦材料是模鍛的或者是編制的石棉,摩擦材料鉚接或粘合在金屬圓片上。離合器片的厚度或成彎曲狀的表面能使離合器的結(jié)合比較的柔和。螺旋彈簧經(jīng)常安裝在輪轂上來(lái)協(xié)助提供對(duì)離合器結(jié)合事的扭曲力的一個(gè)較軟的阻抗。當(dāng)離合器結(jié)合時(shí),花鍵轂緊密結(jié)合到變速器花鍵軸上。
分離軸承通常是一個(gè)安放在分離套筒上的球軸承,并接觸在分離杠桿上,它的作用是給與壓盤接觸的膜片彈簧或者分離杠桿提供壓力。當(dāng)離合器踏板被踩下時(shí),分離軸承或者分離杠桿的壓力驅(qū)動(dòng)壓盤的內(nèi)部連接,放松離合器片,中斷動(dòng)力的傳輸。分離軸承并不是一直與壓盤接觸的,這就該設(shè)置一個(gè)清楚間隙的調(diào)節(jié)器。
離合器踏板給駕駛員提供一個(gè)機(jī)械的方式來(lái)控制離合器的結(jié)合和分離。踏板用鋼索或者桿等機(jī)械連接,鋼索或者桿直接連接到分離軸承的分離叉上。
當(dāng)離合器踏板踩下時(shí),連接系驅(qū)動(dòng)分離軸承的分離叉。分離杠桿接觸在分離軸承的另一端,分離軸承跨在在變速器、離合器軸上,和內(nèi)部的壓盤分離指或者膜片彈簧上。內(nèi)在的壓力作用在分離指上和壓盤的內(nèi)在連接桿上,實(shí)現(xiàn)離合器片離開飛輪,中斷動(dòng)力傳輸。
當(dāng)離合器踏板被踩下,動(dòng)力傳輸被切斷,變速器移動(dòng)到任何齒輪。離合器踏板緩慢的放松,在壓盤彈簧壓力下,離合器片漸漸的向飛輪移動(dòng)。在離合器踏板放開和發(fā)動(dòng)機(jī)轉(zhuǎn)速升高時(shí),離合器片和飛輪之間的摩擦力變大。當(dāng)車輛開始移動(dòng),離合器滑動(dòng)的必要性就減少,離合器踏板就可以完全的放開。
對(duì)于避免發(fā)動(dòng)機(jī)拋錨,動(dòng)力傳動(dòng)系統(tǒng)的組件的沖擊,過多的離合器滑磨和過熱,加速踏板和離合器踏板的協(xié)調(diào)是非常重要的。
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