WEBVTT 00:00:00.704 --> 00:00:04.459 Some technologies are easier to understand with the help of 3D animation. 00:00:07.040 --> 00:00:10.412 But, what about the 6-Speed automatic transmission from Allison. 00:00:13.263 --> 00:00:16.954 To visualize and understand this beautiful planetary gear set mechanism, 00:00:17.060 --> 00:00:19.236 a 2D animation will be ideal. 00:00:19.835 --> 00:00:23.737 You can consider this 2D drawing as a cross section of the 3D model. 00:00:25.040 --> 00:00:28.807 A planetary gear set has 2 inputs and 1 output. 00:00:29.880 --> 00:00:33.250 If you properly understand working of a planetary gear set, 00:00:33.250 --> 00:00:37.340 you can easily understand automatic transmissions from the 2D animation. 00:00:41.990 --> 00:00:44.467 The essence of the planetary gear set is that 00:00:44.467 --> 00:00:47.832 just by giving different speeds to the ring and sun gears, 00:00:47.832 --> 00:00:50.580 you will be able to get different speeds at the output. 00:01:00.070 --> 00:01:02.379 The beauty of automatic transmissions lies 00:01:02.379 --> 00:01:05.036 in how these different input speeds are transmitted. 00:01:05.449 --> 00:01:07.720 Let's see it in the 2D animation. 00:01:11.100 --> 00:01:15.155 This 3D planetary set is represented in 2D as shown. 00:01:17.920 --> 00:01:19.766 In an automatic transmission, 00:01:19.766 --> 00:01:22.430 the input and the output are not directly connected. 00:01:22.653 --> 00:01:25.788 They are connected through an intermediate shaft as shown. 00:01:26.920 --> 00:01:30.003 Now, a small suggestion before you proceed. 00:01:30.003 --> 00:01:32.941 You will be able to explain all seven gears by yourself 00:01:32.941 --> 00:01:36.611 by pausing the video for a moment and understanding the mechanism. 00:01:36.850 --> 00:01:39.140 Please try that at every single gear. 00:01:39.140 --> 00:01:42.252 You will be amazed by the brilliance of this mechanism. 00:01:43.540 --> 00:01:45.617 If you press clutch C1, 00:01:45.617 --> 00:01:48.031 the input will be connected to the sun gear. 00:01:48.402 --> 00:01:52.510 If you press clutch C5, the output rain gear will be stationary. 00:01:53.090 --> 00:01:55.298 This will result in the first gear. 00:01:58.200 --> 00:02:00.245 Now let's add one more gear set. 00:02:00.494 --> 00:02:02.009 Here comes the tricky part. 00:02:02.009 --> 00:02:05.921 The carrier of this set is connected to the ring gear of the first set. 00:02:06.060 --> 00:02:07.170 This simply means that 00:02:07.170 --> 00:02:11.129 the output of the second set is connected to the input of the first set. 00:02:11.810 --> 00:02:16.264 Think for a moment about what happens when you apply C1 and C4. 00:02:19.683 --> 00:02:24.109 Since C4 is applied, the ring gear of the second set will be stationary. 00:02:24.350 --> 00:02:26.148 This makes the carrier turn. 00:02:26.470 --> 00:02:29.549 This carrier is connected to the ring gear of the first set. 00:02:29.720 --> 00:02:32.958 So, the ring gear of the first set will also turn. 00:02:33.180 --> 00:02:36.757 This, in turn, will increase the output speed 00:02:36.920 --> 00:02:39.221 or we will get the second gear. 00:02:40.990 --> 00:02:46.649 To obtain a fourth gear or direct drive, a rotating clutch module is also used. 00:02:47.810 --> 00:02:49.706 We know that for a direct drive, 00:02:49.706 --> 00:02:53.338 both the sun and the ring gear should rotate at the input speed. 00:02:54.283 --> 00:02:59.050 If we press C2 and C1 together, this is what happens. 00:03:01.190 --> 00:03:03.223 In the very same mechanism, 00:03:03.223 --> 00:03:08.132 if you apply C2 and C4 you will get very high speed at the output. 00:03:08.536 --> 00:03:11.390 Think for a moment and try to understand this. 00:03:11.390 --> 00:03:15.430 It is clear that the carrier of the second set will turn at the input speed. 00:03:15.680 --> 00:03:18.645 However, here the ring gear is stationary. 00:03:20.680 --> 00:03:24.701 This makes the sun gear turn at almost three times the speed of the input. 00:03:24.820 --> 00:03:25.710 Eventually, 00:03:25.710 --> 00:03:28.339 a very high output speed is obtained. 00:03:30.640 --> 00:03:34.155 One more gear set is used to obtain the remaining gear ratios. 00:03:34.330 --> 00:03:38.304 However, the sun gear of this set is not connected to the shaft. 00:03:38.410 --> 00:03:41.864 Instead, it is connected to the rotating clutch module. 00:03:41.980 --> 00:03:45.657 So, this sun gear will always turn at the input speed. 00:03:46.260 --> 00:03:47.565 And here again, 00:03:47.565 --> 00:03:51.066 the output of the set is connected to the input of the adjacent set. 00:03:51.950 --> 00:03:55.900 For the remaining gear ratios, C3 is always applied. 00:03:55.900 --> 00:03:59.494 This means that the brown carrier or ring gear of the second set 00:03:59.494 --> 00:04:02.796 will turn at one-third of the input speed for the remaining cases. 00:04:05.550 --> 00:04:08.816 For the third gear, apply see one as well. 00:04:13.200 --> 00:04:17.603 For the fifth gear, apply C2 along with C3. 00:04:22.075 --> 00:04:24.372 The reverse is an interesting mechanism. 00:04:24.620 --> 00:04:28.060 Here, C5 is applied along with C3. 00:04:28.220 --> 00:04:31.785 So here, the carrier of the second set is stationary. 00:04:33.034 --> 00:04:36.957 This means that the planet gears of this set will not be able to revolve 00:04:37.330 --> 00:04:39.030 and that they will simply spin. 00:04:40.160 --> 00:04:43.037 This spin is in the same direction as the input. 00:04:43.205 --> 00:04:44.801 This planetary spin will make 00:04:44.801 --> 00:04:47.931 the corresponding sun gear spin in the opposite direction. 00:04:48.295 --> 00:04:52.951 As a result, the output sun gear will also turn in the opposite direction 00:04:52.951 --> 00:04:54.813 and we will get the the reverse gear. 00:04:55.700 --> 00:04:59.365 We hope that you enjoyed the brilliance of the Allison transmission mechanism. 00:04:59.365 --> 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