Power transmission in battlebot

Hi guys , hope you are having nice days. Today I am going to post my next blog based on battlebot.
My next topic is based on power transmission in battlebot. You all know the material which is required to make a battlebot by my previous blogs but today I am going to tell you that how to transmit power in your battlebot.

Power transmission is main thing which gives power to the whole battlebot and it's weapon system. There are many ways to transfer power easily in your battlebot. I am going to describe all the possible way to transfer power. These are described as:-
1:- Gears: There are 3 main types of gears, as pictured in the next page:
(a) cylindrical gears, with straight or helical teeth;
(b)conical gears, which have perpendicular and convergent axes; and
(c) worm gears, consisting of a worm (which is a gear in the form of a screw) that meshes with a worm gear (which is similar in appearance to a spur gear, and is also called a worm wheel), where the worm and worm gear have perpendicular axes that do not converge.

Among the cylindrical gears, the straight-toothed ones don’t generate axial forces, but they are noisier than the helical ones. The helical-toothed gears are more resistant, however they generate axial forces, except for the double helical ones, which cancel these loads. Grease them well before use, to increase their service life. The TWM 3M gearboxes that drive our middleweights Titan and Touro only use straight-toothed cylindrical gears, in two stages.
The gears are made out of hardened steel to resist impacts. Avoid using cast iron or mild steel gears, they might not resist the rigors of combat.
Conical gears are an efficient option to transmit power at 90 degrees. The gearbox of the weapon system of our spinner Titan uses a large conical gear attached to the weapon shaft, powered in parallel by two S28-150 Magmotors, each one with a smaller conical gear. In the same way as with cylindrical gears, the reduction ratio between two conical gears only depends on the ratio between the number of teeth of each of them. For instance, if the motor gear has 20 teeth and the weapon gear 30 teeth, then the reduction ratio is 30/20 = 1.5, meaning that the torque of each motor will be multiplied by 1.5, and the weapon speed will be 1.5 times slower than the motor speed.
Worm gears are used in several gearmotors, because they can have a large reduction ratio with a single stage. This ratio is equal to the number of teeth of the driven worm gear, which can be a large number. Most of them are self-locking, meaning that the driven worm gear can be designed so that it can’t turn the worm. This can be dangerous in combat, because a large impact can cause the worm gear to break its teeth due to self-locking. Another disadvantage is due to the low efficiency (high power loss) caused by the functional sliding between the worm and worm gear. Because of that,avoid using electric windshield wiper motors, they have low power-to-weight ratios, and the power losses due to the worm gears are high.
2- Belts: Belts are flexible machine elements used to transmit force and power to relatively long distances, driven by pulleys. These elements can replace gears in many cases,with several advantages: besides being relatively quiet, belts
help to absorb impacts and vibrations through their flexibility, and they tolerate some misalignment between the
pulleys. 

The main types of belts are the timing belts (a.k.a. synchronous or toothed belts) and the V-belts manufactured in standard sizes in rubber or polymeric base, in general reinforced with high resistance fibers.
Timing belts keep the relative position between the pulleys, synchronizing the movements and preventing sliding. They can be used to transmit power to the drive system. They can also be used in the robot weapon system, but in this case it is recommended to use some type of torque limiter (discussed ahead) to bear impact loads. V-belts on the other hand, allow the pulleys to have some relative sliding, working as a clutch. This is very useful in combat robot weapons, allowing some sliding at the moment of impact against the opponent, which is good not to stress too much the motor or to rupture the belt. Touro uses a pair V-belts to power its drum.
For small diameter pulleys, use cogged V-belts they are more flexible and dissipate heat better because of the cogged design. Note that they're not timing belts, the cogs are not used as teeth.
If your V-belt broke off in combat and you don't have time during a pitstop to open up your robot to install a new one, then a good alternative is to use an adjustable-length V-belt. Sold by the foot, it is perfect for making replacement V-belts, easily installed by simply twisting its sections for coupling or uncoupling. Its only problem is that it tends to stretch with use, so standard or cogged V-belts are better if you have time to install them.
There are still round belts (with circular cross section), but in general they are only used in low power applications, such as in sewing machines, or in lighter combat robots such as insects.
3: Chains: Chains are also flexible elements used to transmit force and power. They are a good option because they are cheap and they can have any length, you only need to custom define their size using specific tools. Their disadvantages are: they are less efficient than belts, which results in certain power loss; they are noisy; they need tensioners to keep the chains stretched; and they can come out from the sprocket due to misalignments or other deformations, or due to large impacts. 

Since combat robots will suffer several impacts, care should be taken with such transmission type. To avoid these problems, it is a good idea to use short chains, eliminating the need for tensioners, and to protect them very well.

4: Flexible Coupling: Flexible couplings allow a shaft to efficiently transmit power to another one, even in the
presence of misalignments. They consist of 2 rigid coupling hubs, usually made out of cast iron, fixed to each shaft usually using keyways, and of an elastic element (rubber spider) between them, see the picture to the right. They are used in general to connect the motor shaft to the wheel shaft. Besides
tolerating misalignments, they absorb impacts and vibrations, which is highly advisable if your drive system gears aren’t very resistant. 

Our middleweight Ciclone uses such couplings between its wheels and the 18V DeWalt gearmotors that drive them, which helps to prevent an infamous plastic gear inside very old versions of the DeWalt gearbox from breaking. An inconvenience of flexible couplings is their overall length (right figure above), which is relatively large, increasing the distance between the motors and the wheels, which can make your robot become too wide.Avoid using these couplings to power impact weapons, it is likely that the rubber spider won’t take the high impact torques.
Another method to couple misaligned shafts is through universal joints (a.k.a. universal or U-joint). Avoid using them: they are heavy, their strength is relatively low (their pins, which have a much smaller
diameter than the joint itself, are the weakest point), and the energy efficiency is low, getting worse if the shafts have large
misalignments. In combat robots, always try to replace universal joints with belt or chain transmissions.

5: Torque Limiter: Torque limiters are power transmission elements that allow relative sliding between the coupled components, acting as a clutch. They are an important component in impact weapons that do not use V-belts or some other element that acts as a clutch to limit the torques transmitted back to the robot. 

The figure  shows the torque limiter used by our middleweight bar spinner Ciclone, the DSF/EX 2.90, manufactured by the Italian company Comintec. The spinning bar is sandwiched between 2 flanges, one fixed and the other movable. The movable flange is fastened onto the bar, applying a constant pressure with the aid of a Belleville washer, in such a way to transmit friction torques to accelerate the weapon bar. The flanges allow the bar to slide in the event of an impact, acting as a clutch.
It is not necessary to buy an off-the-shelf torque limiter. It is possible to build yourself much smaller, lighter, more resistant and cheaper versions. You basically need two flanges attached to a shaft, which can be two sturdy hardened steel shaft collars – a plain one and a threaded one to be tightened with the aid of a Belleville washer against the driven element such as the weapon bar.
Phenolic laminates such as garolite are a good clutch material to be inserted in between the collars and the bar. The torque limiter from our spinner Titan is much smaller than Ciclone’s, because the lower flange is already embedded onto the weapon shaft, saving weight and increasing strength. It is then enough to use a Belleville washer and a threaded collar to attach its weapon bar.

This is the all information related to the transmission of power in your battlebot. If you guys have any questions related to this then comment down below all your queries so that I can help you to overcome it. Also don't forget to see my previous blogs based on battlebot and many other technical stuffs. I hope you like my today's blog. I am providing link to my previous blogs below.

https://indianmegabot.blogspot.com/2018/06/material-required-to-build-battlebot.html?m=1

Thanks!!!