機(jī)械設(shè)計(jì)制造及其自動(dòng)化專(zhuān)業(yè)英文翻譯-文庫(kù)吧資料
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【正文】 nd the clutch drum. Notice the rubber seal on the piston this is one of the ponents that is replaced when your transmission gets rebuilt. One of the clutches in a transmission The next figure shows the alternating layers of clutch friction material and steel plates. The friction material is splined on the inside, where it locks to one of the gears. The steel plate is splined on the outside, where it locks to the clutch housing. These clutch plates are also replaced when the transmission is rebuilt. The clutch plates The pressure for the clutches is fed through passageways in the shafts. The hydraulic system controls which clutches and bands are energized at any given moment. FROM: 2021屆 機(jī)械設(shè)計(jì)制造及其自動(dòng)化 專(zhuān)業(yè) 外文翻譯 13 自動(dòng)變速器的工作原理 耐斯ll see how these work. Clutches and Bands in an Automatic Transmission In the last section, we discussed how each of the gear ratios is created by the transmission. For instance, when we discussed overdrive, we said: In this transmission, when overdrive is engaged, a shaft that is attached to the housing of the torque converter (which is bolted to the flywheel of the engine) is connected by clutch to the pla carrier. The small sun gear freewheels, and the larger sun gear is held by the overdrive band. Nothing is connected to the turbine。s go back to our chart again, this time with the pla carrier for input, the sun gear fixed and the ring gear for output. Ratio = 1 / (1 + S/R) = 1 / ( 1 + 36/72) = :1 So the output spins once for every twothirds of a rotation of the engine. If the engine is turning at 2021 rotations per minute (RPM), the output speed is 3000 RPM. This allows cars to drive at freeway speed while the engine speed stays nice and slow. Reverse Reverse is very similar to first gear, except that instead of the small sun gear being driven by the torque converter turbine, the bigger sun gear is driven, and the small one freewheels in the opposite direction. The pla carrier is held by the reverse band to the housing. So, according to our equations from the last page, we have: Ratio = R/S = 72/36 = :1 So the ratio in reverse is a little less than first gear in this transmission. Gear Ratios This transmission has four forward gears and one reverse gear. Let39。s a speed increase the opposite of a reduction. In this transmission, engaging the overdrive acplishes two things at once. If you read How Torque Converters Work, you learned about lockup torque converters. In order to improve efficiency, some cars have a mechanism that locks up the torque converter so that the output of the engine goes straight to the transmission. 2021屆 機(jī)械設(shè)計(jì)制造及其自動(dòng)化 專(zhuān)業(yè) 外文翻譯 9 In this transmission, when overdrive is engaged, a shaft that is attached to the housing of the torque converter (which is bolted to the flywheel of the engine) is connected by clutch to the pla carrier. The small sun gear freewheels, and the larger sun gear is held by the overdrive band. Nothing is connected to the turbine。 the ring gear (large sun gear) is held stationary by the band, and the output is the pla carrier. For this stage, with the sun as input, pla carrier as output, and the ring gear fixed, the formula is: 1 + R/S = 1 + 36/30 = :1 The pla carrier turns times for each rotation of the small sun gear. At the second stage, the pla carrier acts as the input for the second plaary gear set, the larger sun gear (which is held stationary) acts as the sun, and the ring gear acts as the output, so the gear ratio is: 1 / (1 + S/R) = 1 / (1 + 36/72) = :1 To get the overall reduction for second gear, we multiply the first stage by the second, x , to get a :1 reduction. This may sound wacky, but it works. Third Gear Most automatic transmissions have a 1:1 ratio in third gear. You39。 this bination reverses the direction. You can see that this would also cause the bigger sun gear to spin。ll put the two sets of gears together in the next section. Compound Plaary Gearset This a
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