機(jī)械設(shè)計(jì)制造及其自動(dòng)化專業(yè)英文翻譯-文庫吧
2024-11-16 00:00 本頁面
【正文】 39。s take a look at a single plaary gearset. One of the plaary gearsets from our transmission has a ring gear with 72 teeth and a sun gear with 30 teeth. We can get lots of different gear ratios out of this gearset. Input Output Stationary Calculation Gear Ratio A Sun (S) Pla Carrier (C) Ring (R) 1 + R/S :1 B Pla Carrier (C) Ring (R) Sun (S) 1 / (1 + S/R) :1 C Sun (S) Ring (R) Pla Carrier (C) R/S :1 Also, locking any two of the three ponents together will lock up the whole device at a 1:1 gear reduction. Notice that the first gear ratio listed above is a reduction the output speed is slower than the input speed. The second is an overdrive the output speed is faster than the input speed. The last is a reduction again, but the output direction is reversed. There are several other ratios that can be gotten out of this plaary gear set, but these are the ones that are relevant to our automatic transmission. You can try these out in the animation below: 2021屆 機(jī)械設(shè)計(jì)制造及其自動(dòng)化 專業(yè) 外文翻譯 5 So this one set of gears can produce all of these different gear ratios without having to engage or disengage any other gears. With two of these gearsets in a row, we can get the four forward gears and one reverse gear our transmission needs. We39。ll put the two sets of gears together in the next section. Compound Plaary Gearset This automatic transmission uses a set of gears, called a pound plaary gearset, that looks like a single plaary gearset but actually behaves like two plaary gearsets bined. It has one ring gear that is always the output of the transmission, but it has two sun gears and two sets of plas. Let39。s look at some of the parts: How the gears in the transmission are put together Left to right: the ring gear, pla carrier, and two sun gears The figure below shows the plas in the pla carrier. Notice how the pla on the right sits lower than the pla on the left. The pla on the right does not engage the ring gear it engages the other pla. Only the pla on the left engages the ring gear. 2021屆 機(jī)械設(shè)計(jì)制造及其自動(dòng)化 專業(yè) 外文翻譯 6 Pla carrier: Note the two sets of plas. Next you can see the inside of the pla carrier. The shorter gears are engaged only by the smaller sun gear. The longer plas are engaged by the bigger sun gear and by the smaller plas. Inside the pla carrier: Note the two sets of plas. 2021屆 機(jī)械設(shè)計(jì)制造及其自動(dòng)化 專業(yè) 外文翻譯 7 Automatic Transmission Gears First Gear In first gear, the smaller sun gear is driven clockwise by the turbine in the torque converter. The pla carrier tries to spin counterclockwise, but is held still by the oneway clutch (which only allows rotation in the clockwise direction) and the ring gear turns the output. The small gear has 30 teeth and the ring gear has 72, so the gear ratio is: Ratio = R/S = 72/30 = :1 So the rotation is negative :1, which means that the output direction would be opposite the input direction. But the output direction is really the same as the input direction this is where the trick with the two sets of plas es in. The first set of plas engages the second set, and the second set turns the ring gear。 this bination reverses the direction. You can see that this would also cause the bigger sun gear to spin。 but because that clutch is released, the bigger sun gear is free to spin in the opposite direction of the turbine (counterclockwise). Second Gear 2021屆 機(jī)械設(shè)計(jì)制造及其自動(dòng)化 專業(yè) 外文翻譯 8 This transmission does something really neat in order to get the ratio needed for second gear. It acts like two plaary gearsets connected to each other with a mon pla carrier. The first stage of the pla carrier actually uses the larger sun gear as the ring gear. So the first stage consists of the sun (the smaller sun gear), the pla carrier, and the ring (the larger sun gear). The input is the small sun gear。 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
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