Working Principle Of Manual Gearbox

Working Principle Of Manual Gearbox. The Role Of Synchronizers.

 

Hello everyone, I wish you a very good day. Dear friends, the other day a friend asked me to work on the structure and operation of the gearbox on a car, today I would like to present the structure and main operating principle of the manual transmission, As for the automatic transmission, I would like to present it in the next video.

Operating Principle of Manual Transmission 5
Firstly, when talking about the manual transmission in particular and the gearbox in general, its effect is to change the traction of the car, when we move in different conditions and help us have can reverse. Since the change in traction is done through connecting gears of different diameters, the ratio between the diameters or the number of teeth between the gears when coupling is called the gear ratio. . Then in different situations we need to go with different levels, for example, when we start moving or climbing slopes, we have to go in low gear, and when we go on flat roads. With high speed, we have to go to high gear, then in general, these things you probably already know very well, I would like to stop talking at length, I would like to go into the structure of the manual transmission, then for each car company, they will have different manual transmission mechanisms.

Operating Principle of Manual Transmission 6
But in general, it also includes the following main parts, then on the picture is the structure of some 5-level floors, then you see that the input is on the left hand side that is the primary shaft, then this axis is receives the movement from the engine through the clutch, and the part of the shaft behind it is called the secondary shaft, and the shaft below is called the intermediate shaft, on this shaft are arranged gears and it are already engaged, the gear that is on the primary shaft and the gears that are on the intermediate shaft is locked to the shaft. What about the gears that are on the secondary shaft, it has 2 types of gears: One is the type of gears that, when engaged with the gears on the intermediate shaft, those gears will rotates smoothly and has gears to which it is fixed to the secondary shaft. But the outside of it is tucked into a sleeve, you can notice the sleeves here are metal rings that have a groove in the middle, a groove in the middle of it. will drive a bar into it, the sleeve can move along the secondary shaft.
Then when it moves left or right, it will engage the gears that are rotating smoothly on that shaft, reattach to the secondary shaft, from there it will transfer the force to the secondary shaft through. through that gear, each sleeve has a lever arm, and when we hold the gear lever we move these lever arms, these swingarms will rest on the rim of the sleeve and from there it will slide left or right or stand in the middle then when it's in the middle it won't mesh with any gear, So how does the coupling between when a gear is rotating smoothly and a gear fixed on the secondary shaft, how will it connect? Then we can observe the following illustration:

First look at the picture, we will see that the red gear is the gear that rotates smoothly on the shaft, and the blue gear is the gear that is fixed on the shaft and this gear is fixed. fits the sleeve on the inside of the sleeve it also has teeth that fit this fixed gear, so you can see that the sleeve it can slide on the wheel this fixed tooth, and when it slides it will engage with the red gear again, which means the gear has turned smoothly and then it will connect the two into a solid gear, but one problem The problem is that the gear rotates smoothly, that is, the red gear, and the fixed gear on the secondary shaft is the blue gear, when they are not engaged, their speed is different.

Operating Principle of Manual Transmission 7
So how can we coupling two gears that have different rotational speeds, linked together? Then to solve this problem, people will put a synchronous speedometer between these two gears, then the synchronizer is actually a thin ring on which it also has a tooth system, then as you observe, you can see that on the synchronizer, its teeth, it will correspond to the number of teeth that the two gears need to fit together, and the teeth that on the synchronizer with the teeth, but on the gear that rotates smoothly, the gear is red, you see it will carry a… at one end it will be carried away, how does the synchronous motor work? This speed can be described like this:

When the sleeve it needs to connect between the blue gear and the red gear, it will first engage with the synchroniser again, then when it gets on with the synchroniser then the two synchronizers and the sleeve, it will become a unified block and it goes it close to the red gear, when the synchronizer it gets close to the red gear, then with the the force that is specifically here is the frictional force between the synchronizer and the red gear, it will make this system stick together and move at the same speed, when it moving at the same speed, it's easier to slide with the sleeve in contact with the red gear, we notice that at the top of the red gear the its teeth, it's going to be carried like this, it's being carried diagonally, so if the synchro can match the red gear in any position, the he slides the sleeve over his head to match get back with red gear.

So if I don't know how to present it, can you imagine it? But in terms of structure it will be like that, it takes advantage of the friction between the synchronizer and the gears, it will make them move at the same speed, then the coupling it will be easier. So the principle of this synchroniser is generally the same, but on each car company, people design the structure, it's a little different in detail, you can see that There are cars that when in gear it is very smooth, and cars when it is not very smooth when it is in gear, it is all because of this speedometer.

If you want to go into gears smoothly, this synchroniser, it will have to work smoothly, then you can see the illustration above, this is the mechanism that when people put into gear, from the number 1, 2, 3, 4 and then there is the number 5, with each sleeve on the secondary axis, it will fit into two numbers again, ie sliding to the left is a number that misses to the right is a number, the thing that slides back and forth is that it's because our gear lever will push the pushers, make the sleeve move, then that's the case and forward gear if we have reverse gear.

Operating Principle of Manual Transmission 8
That is, we have to reverse the rotation of the secondary shaft, then one will add an intermediate gear, then here the mechanism that shows reverse is shown in those three gears. are red, green and blue, then the red gear and the green gear are fixed on its shafts i.e. red gear it is fixed on the secondary shaft, and the green gear is fixed on the intermediate shaft. These two gears, normally it will not mesh with each other, only when the blue gear it engages with both, then these two gears will have the movement through. together. In this place, when people put the intermediate gear in place, they will push the whole gear in. Then people design the mechanism that fits without such a synchronous gear for a purpose that is, we can only stop the car completely, then we can enter the reverse gear.

So, on cars with manual or other gears, we cannot enter reverse while the car is running, it must be stopped completely before we can match these gears together. , because between them the articulating mechanism does not have a synchronizer, and in the gearing processes, in order to prevent these sleeves from sliding freely, they are arranged in spindles. the pusher, the grooves, and it has the ball and the spring is attached, then when the shuttle pushes it slide it has only three positions, it will hold those three positions, it is the one that holds the position, the position of its sleeve in the middle matching the left side and matching the right side, then once it's matched, it avoids making the sleeve slip. Well that's the general principle of the gear shift, then I think I should just present this issue, as for the gear ratio and how the gear box layout is, then the You can refer to the websites that have also been very specific about this issue.

Well, I only consider the aspect of the mechanism when it is geared, how does it work from the synchroniser, then by the way, I will talk about some other issues about the gearbox. In general and manual gearboxes in particular, the first thing you look at is the gear that when it fits together. Then their tooth system… its not going to be straight, it will be carrying it a little diagonally, why do people do it like that? Because, when the gears are aligned with each other, even though they are close together, in fact it still has a gap, then if we design it with a straight gear shape, the collision will keep these teeth it will directly impact that tooth and it will make its tooth wear down faster. Then they make it bevel a little to reduce the force of the angular force on the tooth, it will be more durable, and when it engages in this way, the mechanism engages so it will be quieter. .

And the second problem I want to present here, is that when we learn to drive, the teachers advise that we go uphill with any number, we will go downhill with that number, why? again like that? Then when we go uphill, we will of course need a low gear, when the number is low, the pull it will be large, from which we will go uphill more easily. Then according to physics, the Newton's law says that the force and the reaction always go together and have the same magnitude, so if the force acting is larger, the force will be exhausted. greater.

So when we go downhill, because it's low, it gives us great traction. It means that the resistance it corresponds to is also large, so when going downhill we will take advantage of this resistance we move downhill slowly, then it will be safe. than. Especially on steep but dangerous roads, the thing that goes to low gear when going downhill, drivers often call it engine braking, that is, we take advantage of the great resistance of the engine when driving downhill. but in low gear so that we slow down the slope slowly. So above, I have presented about the gearshift mechanism of the manual transmission, and the other types of gearboxes, I would like to present in the next session.

So today's video, I would like to pause here, if there is anything you need to comment or share, please comment below. Thank you very much for your follow up and friends! Hello and see you in the next videos.

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