In a conventional manual gearbox, such as the one in your own car, the drive is briefly disconnected when the driver selects a new gear by depressing the clutch. With an F1 gearbox, it is crucial.
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Transcription
Hi, I’m Scott Mansell. In this video, I’m going to take a look at what’s inside this Formula One gearbox and explain a little bit about how it works. Today, I’m in the workshop of Mansell Motorsport who restore and look after many Formula One cars from the mid-’90s to the mid-2000s. They’ve been kind enough to give me this 1997 Jordan F1 Gearbox for me to open up and have a look at how the internals actually work.
Before I get into taking this gearbox apart, I think it’s important to understand the position of the gearbox within the Formula One car itself. Mac vmware for amd. As you know, at the front of the Formula One car where the driver sits, we have the tub which is made out of carbon fiber. Then behind that, on four studs, we have the engine bolted directly onto the tub. Behind the engine, we have the gearbox bolted directly to the engine. All of these parts are stressed members. They’re part of the chassis, meaning that the rear suspension is in fact bolted directly on to the gearbox.
This is the front of the gearbox casing. It’s made out of cast magnesium. You can see this input shaft at the bottom just down here. This is connected directly to engine and it’s where the power comes through from the engine onto the layshaft of the gearbox. In terms of changing gear, we need to head around to the side of the gearbox. What you can see just here is the change cylinder. The driver makes the shift request with the paddles on the steering wheel, either up or down. It then goes through the GCU. The change cylinder here, which, in this case, is pneumatic with air either fires the gears down or up the gearbox.
If I just put this handle on here, if you watch the end of the cylinder, you can see it moving. Obviously, the force would come from this side and it would change the gears up or down. Before we can get into the gear cluster, I need to take off the rear diff housing. In this section of the gearbox and the rear diff housing, the diff gear and diff would sit in here. In the side here come the driveshaft. We have the driveshafts would then go out to the uprights, which are then, obviously, attached to the wheels and so the power can go through the gearbox, the diff, and into the track.
Now, I’ve removed all of the nuts from the diff casing. Time to try and take it off. Now, you can see that I’ve opened up the diff casing away from the gearbox casing to my right. You can see here that this is the main shaft that comes out the top of the gearbox. This gear, this bevel gear, drives this gear, which is then, obviously, connected to this gear, which then would go behind here onto the diff gear and rotate here, which then goes onto the drive shafts, which then, obviously, goes to the uprights, and through the wheels, and into the racetrack.
This, just on the top, inside the gearbox casing here, is the gearbox oil tank. You can see it’s got an opening here. Well, behind that, if you imagine back here the diff gear coming around and around just in this position here, then all the oil that collects then gets flicked into the gearbox oil tank for then distribution around the rest of the gearbox.
If you look closely, these nuts here and take the oil tank off at the top. The cassette should come out here. We’ve got the main shaft here and the layshaft at the bottom, which I’ll explain once we’ve taken out, as it’s a little bit easier to explain once you can see all of the moving parts.
Here we go. Let’s have a look at those gears.
First of all, you can see here that we have the layshaft that runs across the bottom. That turns the main shaft that runs across here. The layshaft is the one that’s connected to the engine, the engine comes out of here and powers this layshaft. Now, none of the gears on here actually turn away from the shaft. They’re directly splined onto the shaft itself. From the size of them, with this one being the smallest just here, you can see that this is first gear, these pair of gears. This is second here and then we jump across here, third, fourth, fifth, sixth and seventh with these gears just here. The power from the engine drives the layshaft here which then turns all the gears on this top shaft.
I’ve just put this piece of wood in place so you can actually see the gears turned. We can see here because all the gears are turning freely, you imagine the engine power coming here, we’re spinning all the gears but nothing on this left-hand-side is going into the diff. You can see here that the car or the gearbox is actually in neutral because there’s no power or no drive coming at the back of the gearbox here and going to the diff.
How do we actually change gear? Well, I showed you earlier on the change cylinder on the outside of the gearbox that moves forwards and backwards and then shifted the change mechanism. Well through the internals of the gearbox that’s actually connected to this. This is the barrel and the selector shaft along here. As the change goes through the change cylinder, it actually comes here and moves this barrel around which then moves this piece here which is the selector fork across.
We’ve got the engine running. The power is coming through here onto the layshaft, the gears are turning on the main shaft at the top but the gear at the back here, the main isn’t actually turning. It’s just the gears that are spinning on top of the main shaft, we’re in neutral. Then the driver pulls a gear and it goes into first gear. You can see the selector fork here move across and we take first gear just here. Let me simulate the engine moving. Pick the shaft up again. You can see that the gear, the main shaft is actually rotating now all the way through, we’re in-gear. Then the driver selects another gear, the selector fork moves across and we take second gear. Sorry, it just fell out. Now, at the back, you can see that the main shaft is spinning again. Then we go up another gear and if you watch this selector fork, we head into third gear and again, it’s all locked up on that main barrel and we take third gear. Again into fourth, you can see this selector fork move across fourth, fifth, sixth and seventh. We’re in seventh gear, sixth gear, fifth gear, fourth gear, third gear, second gear and first gear’s just gone dog to dog.
That’s a really good way to show it. You can see that we’ve gone from first, second, third, fourth, fifth, sixth and seventh. You can see there that the timing is obviously absolutely perfect. When we go from one gear across into second– now watch this selector fork and this selector fork. We go from second here, that then comes into the neutral position into between these two dogs. Then the third gear moves across. That then moves away from the dogs and disengages this gear just before the fourth selector fork moves across and engages fourth gear and again the process continues all the way along. That’s an absolutely beautiful piece of engineering that you can see there.
To better explain the gears on the main shaft which is the more complex of the two shafts. I’ve gone and picked up a few spares off the shelf. On the layshaft, you can see here that this hub is splined. The main shaft has spline like this and this hub fits over the main shaft. Then you can see here that we are splined on the outside of the hub as well. Those splines are so this dog ring can fit over the top and stay have movements side to side, lateral movements side to side but stay connected and can drive the gear that’s attached to this hub.
Three Shaft Gear Box
Then on this section of the hub, we have a bearing as you can see in here that spins and then we have the gear that goes over the bearing. As you could see before, the gear is actually, let me just remove this dog ring, the gear is actually not connected to the hub. It is not driven all the time by the shaft. Then when we put on the dog ring and this is how we can change gear to select a fork that I showed you earlier and actually it goes over the dog ring like this. The selector fork moves across and then engages the gear, which means that the gear then drives the shaft which then goes straight to the diff and can drive the rear wheels.
One important thing to note is the cut of the dog just here, you can see that it isn’t at 90 degrees to the gate it’s actually cut like this. Now, the reason for that it’s when the gear and the dog ring come together when it’s being driven, when it’s loaded they actually pull each other together and when you put in seven or eight hundred brake hosepipe through these gears, it’s obviously very important that mechanically they drive each other together.
That’s all for this video. Thank you very much for watching and if you did enjoy this type of video, please let me know in the comments below and be sure to subscribe if you haven’t already. Thanks and I will see you next time.
Just like in your family road car, F1 cars have a clutch, gearbox and differential to transfer the 800 bhp into the rear wheels. Although they provide the same function as on a road car, the transmission system in an f1 car is radically different.
F1 Gearbox Ratio
A good engine must be installed well to perform to its ultimate ability, and it must output its power to the wheels in the best way possible. The engine is connected to the flywheel, which is linked to the drive shaft via the clutch plates. The drive shaft goes into the gearbox, which is connected to the axles (and therefore the wheels) through the gears and differential.
Having explained how the gearbox works in my article, the next thing to consider is how to change between gears. This is done using the clutch. But why? Well, with the gear wheel on the end of the drive shaft rotating in the gearbox, it is not going to be easy to move it through the gears to meet up with another gear. Any attempt to do so will result in that annoying, grinding noise heard all too often from a poorly driven car! That noise is the noise of the rotating gear wheel on the drive shaft grinding against one of the gears in the gearbox - carry on with that, and you're going to be left with a gearbox full of metal shreds! Or worst!
This is why the drive train in a car incorporates a clutch. In F1, they are multi-plate designs that are designed to give enhanced engine pick-up, and the lightweight deigns with a small diameter mean that they have low inertia, allowing faster gear changes. Flying wheel on F1 car is just 10 centimeters in diameter. The drivers do not normally use the clutch manually, apart from moving off from standstill, during pit stop and in case of emergency or spin. They simply press a gear change selector lever behind the wheel to move to the next ratio. The on-board computer automatically cuts the engine, depresses the clutch and switches ratios in the blink of an eye.
In the world of the F1 semi-automatic gearbox, of course, there is no need for the driver to even think about this – everything is electronically controlled! All the driver is required to do is to pull paddle when he wants to change up or down a gear, and the electronics controlling the gearbox and clutch do the rest. The advantages here, over and above the fact that the driver can keep his hands on the wheel at all times, is that the whole process can be done in a split second (much quicker than a manual clutch could be operated) and also that the wear on the clutch pads is less because it is never held half-on, and so this increases reliability.
The engine and transmission of a modern Formula One car are some of the most highly stressed pieces of machinery on the planet.
Traditionally, the development of racing engines, transmissions and the rest of F1 car has always held to the rule of the great engineer Ferdinand Porsche who stated that the perfect race car crosses the finish line in first place and then falls to pieces. Although this is no longer strictly true - regulations now require engines to last five race weekends, and gearbox's four - designing modern Formula One engines remains a balancing act between the power that can be extracted and the need for JUST enough durability.
The start phase in Formula 1 is very important. Beginning and first highlight of every race. Decisive fractions of a second. So much is at stake during the first few hundred meters of a Formula 1 race today that some of the most sophisticated and secret engineering on the cars is been devoted to help a driver during those first couple of seconds, during which he attempts to get his car off the line and up to speed quicker than those around him on the grid. The prize was the order of cars into the first corner, which in today's racing so often dictates the order for the rest of the race. Of course, that was until year 2007!!! Previously the drivers could rely on highly sensitive and fast electronics during this critical phase - from 2008 no longer. With effect from this year, the regulations forbid the use of ANY start electronic assistance and traction control in race phase. With common ECU this is easily controlled by FIA. Sensitive handwork during the start is again in demand. And that should be taken literally, because in the F1 the commands to the gearbox and clutch are distributed by means of a steering wheel mounted paddles. Transmissions may not feature traction control systems, or devices that help the driver to hold the clutch at a specific point to aid getaway at the start of the race.
After abolishing all electronic help during the start phase Thomas Rudolf, engineer for clutch systems at ZF Sachs Race Engineering explained 'We see the return to handwork from a technical view point with mixed feelings'.
The ZF Sachs AG motorsport department equips the Formula 1 teams of Ferrari, Honda, Toyota and some other teams with clutches and shock absorbers.
With electronic control and help, the clutch got rid of surplus power with slips between carbon clutch plates. As a result, this important interface in the drive train was subject to extremely high loads, for up to two seconds and in exceptional cases even up to ten seconds and heated to temperatures in excess of 1000 degrees Celsius.
The engineer explains why: 'In contrast to a normal car with a clutch pedal, the Formula 1 driver doesn't feel a pressure point with his paddle. He must REMEMBER in which paddle position the gear is engaged. It is a balancing act. Even top drivers like Michael Schumacher can slip the clutch for only a maximum of half a second as to help to pull away. This is not enough, and is only a quarter of the time that the electronic help function for pulling away demanded.'
A few key figures illustrate these extreme loads that impact on the F1 clutch from ZF Sachs weighing no more than roughly 860 grams: the diaphragm springs apply 1.6 tons of pressure to the three clutch plates, and the tiny 100-millimetre titanium housing withstands temperatures of up to 700 degrees centigrade.
Does the new regulations therefore guarantee an easier time for the clutch? No. Because, where the human element is involved mistakes happen. If a driver misses the pressure point and releases too fast, the engine could stall, he disengages the clutch again, lets the engine revs skyrocket and tries to reengage the clutch again. Often, the whole process is repeated several times. As a result even higher loads and temperatures can occur. Even if such mistakes are not the rule, engineers who construct the clutch must make provision for them. That's why they have refrained from reducing the reserves released through the abolition of the electronics.
In fact the Sachs Formula 1 clutch of 2008, at the same overall dimensions as its predecessor, is even more efficient. The technicians reduced the clutch hub size of previous successful model, but anyway they gain more room for the stressed carbon disc friction faces. The diaphragm spring, which clamp the friction plates with a force of 1.6 tones, are produced from special steel alloy resistant to temperatures of up to 700 degrees Celsius. Also the tiny titanium housing with a diameter of around 100 millimeters is, thanks to an even further optimized machined contour, more robust. Sachs expects the component longevity to have increased by a factor of three. The housing is particularly stressed by engine vibrations. 'Although the engines must last a two race-weekend, the relevant key data for us remains almost unchanged. The power units still rotate at 18,000 rpm and are actually lighter rather than heavier. And the lighter an engine is, more it vibrates, which wears out the clutch housing', explain Sachs engineer.
Formula 1 Transmission System
The new gearboxes that have to last for four races also have no influence on the clutch. From the technical point of view Formula 1 racers do not require a clutch to shift in the higher gears. The loads resulting from this have already been taken into account for years.
For safety reasons all cars must have a means of disengaging the clutch that is operable from outside the cockpit by marshals. This control is usually situated just ahead of the cockpit opening and is marked on the car's body by a red letter 'N' within a white circle.
When you hit the throttle, the engine spins the flywheel, as we explained before. The flywheel transfers energy to the gearbox that is transferred to the differential, who's duty is to spin the tires putting the power to the ground. One very important part of the machinery lay in between differential and the wheel. The drive shaft, some time called half shaft, is only link between the gearbox/differential and the rear wheel. The problem is that the common view about the drives haft is 'it's a simple link'. The fact is, while you can't gain horsepower through the drives haft, you can certainly lose it. Drive shafts are carriers of torque: they are subject to torsion and shear stress, equivalent to the difference between the input torque and the load. They must therefore be strong enough to bear the stress, whilst avoiding too much additional weight as that would in turn increase their inertia.
To allow for variations in the alignment and distance between the Differential and upright, drives hafts must incorporate one or more universal joints. In Formula 1, there is only one joint called yoke, slip yoke or slip joint, located on one end of the drives haft, connecting point between differential and drives haft. The slip-yoke and the pinion-yoke take a lot of abuse in a high-performance application. These are the physical connectors to the transmission, drives haft, and differential. All torque and power is transferred trough this joints. In most applications a cast pinion-yoke is usually strong enough to handle more than 800 hp. That number has some fudge room, though, as a lightweight Formula 1 car with 800 hp will usually put less strain on the yokes than a 2 tonne car with slick tires and 500 horses. When the slip-yoke fail, it can wipe out just about everything it could in his vicinity.
What the drives haft is made of is just as important as its length and diameter. Some time ago, drives haft use to be made of chrome-moly or lightweight aluminum. Chrome-moly, is the strongest possible metallic material and usually seen in Pro Stock cars. Chrome-moly steel tubing can be heat-treated as well, raising the torsional strength 22 percent and increasing the critical speed 19 percent. The problem with steel is it is heavy, which increases the load on the drivetrain. Aluminum is probably the most common performance drives haft material.
The lightweight aluminum shaft reduces rotational mass, freeing up horsepower from the engine and reducing parasitic loss. An aluminum drives haft will support 900 and up to 1,000 hp, making it a great lightweight choice for most muscle cars. However, it is not as strong as steel, so some custom drives haft shops do not have twist guarantees on aluminum drives hafts.
Modern Formula 1 use carbon fiber. Carbon-fiber tubes are the most expensive, but they are also the most efficient. When you are looking at power figures up to 1,500 hp, carbon fiber is a great choice. Carbon-fiber drives hafts are not only strong, but they also have a surprisingly high torsional strength, resisting twisting and reducing the shock factor on the rear end. Carbon fiber also has the highest critical speed module of elasticity, meaning the shaft won't flex at slower speeds, unlike other material components. Coupled with the highest critical speed and the light weight, a carbon-fiber drives haft can free up some horse power over aluminum, and especially over chrome - moly tubing. When winning is everything, that might make the difference.
What is most often cause of drives haft failure is reaching critical speed. All drives hafts have a critical speed. Critical speed is the RPM at which the drives haft becomes unstable and begins to bend into an S shape. The longer and smaller diameter a drives haft is, the lower its critical speed. Critical speed is felt as excessive vibration that will cause the unit to fail. To calculate the critical speed, the length, diameter, wall thickness, and material module of elasticity must be known. There is a complex formula to calculate the critical speed for every drives haft. The module of elasticity of the shaft material is an important part of the equation. For steel, the basic MOE is 30, aluminum is 10, and carbon fiber depends on the manufacturing processes used, so no numbers are available.
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