Many authorities have excluded steam powered, electric motorcycles or diesel-powered two-wheelers from the definition of a 'motorcycle', and credit the Daimler Reitwagen as the world's first motorcycle.[17][18][19] Given the rapid rise in use of electric motorcycles worldwide,[20] defining only internal-combustion powered two-wheelers as 'motorcycles' is increasingly problematic. The first (petroleum fueled) internal-combustion motorcycles, like the German Reitwagen, were, however, also the first practical motorcycles.[18][21][22]
Two Wheeler Mechanism Pdf Download
In the 21st century, the motorcycle industry is mainly dominated by Indian and Japanese motorcycle companies. In addition to the large capacity motorcycles, there is a large market in smaller capacity (less than 300 cc) motorcycles, mostly concentrated in Asian and African countries and produced in China and India.[citation needed] A Japanese example is the 1958 Honda Super Cub, which went on to become the biggest selling vehicle of all time, with its 60 millionth unit produced in April 2008.[41]Today, this area is dominated by mostly Indian companies with Hero MotoCorp emerging as the world's largest manufacturer of two wheelers. Its Splendor model has sold more than 8.5 million to date.[42] Other major producers are Bajaj and TVS Motors.[43]
Cars, clocks, and can openers, along with many other devices, use gears in their mechanisms to transmit power through rotation. Gears are a type of circular mechanical device with teeth that mesh to transmit rotation across axes, and they are a very valuable mechanism to know about as their applications range far and wide. In this Instructable I'll go over some basic gear concepts and interesting mechanisms, and hopefully you'll be able to design your own gear systems and make stuff like this!
Gears are a very useful type of transmission mechanism used to transmit rotation from one axis to another. As I mentioned previously, you can use gears to change the output speed of a shaft. Say you have a motor that spins at 100 rotations per minute, and you only want it to spin at 50 rotations per minute. You can use a system of gears to reduce the speed (and likewise increase the torque) so that the output shaft spins at half the speed of the motor. Gears are commonly used in high load situations because The teeth of a gear allow for more fine, discrete control over movement of a shaft, which is one advantage gears have over most pulley systems. Gears can be used to transmit rotation from one axis to another, and special types of gears can allow for the transfer of motion to non-parallel axes.
There are a handful of different types of gears and gear mechanisms, and this Instructable definitely doesn't cover all of them. I hope that this guide will give you a sense for how you can use gears to improve your mechanical design techniques. In the next few steps I'll be starting with some of the simplest types of gears and gear mechanisms and going into some of the more complicated, interesting ones as well. If you're really interested in learning more, I would suggest you check out this book, 507 Mechanical Movements, as it comes with a lot of really neat mechanisms!
Worm gears can thus be used to drastically reduce the speed and increase the torque of a system in only one step in a small amount of space. A worm gear mechanism could create a gear ratio of 40:1 with just a 40 tooth gear and a worm, while when using spur gears to do the same, you would need a small gear meshing wit another 40 times its size.
Cage and peg gears are a certain style of gear mechanisms that are much easier to make, because they can be made cheaply out of wooden boards and dowels. However, they are not very good for high speed or high load situations because they are usually made with a lot of backlash and wiggle-room. Cage and peg gears are mostly used to transmit rotation between perpendicular axes. A peg gear is basically a disc with short pegs sticking out from it around its circumference (to form a spur gear), or on its face parallel to the axis of rotation (to form a bevel gear). The pegs in these gears act as the teeth, and contact one another to spin each of the gears. A cage consists of two discs with pegs running between them parallel to the axis of rotation. A cage gear can be used like a worm gear, as each of the dowels on the gear contact the pegs on a normal peg gear. However, this system can be driven from either end.
A mutilated gear is a gear whose tooth profile does not extend all the way around its pitch circle. Mutilated gears can be useful for many different purposes. In some cases, you may not need the entire tooth profile of a gear because the gear may never need to rotate 360 degrees, and you could have a linkage, beam, or other mechanism as part of the mutilated side of the gear. In other cases, you may want the mutilated gear to rotate 360 degrees, but you may not want it to be turning another gear all the time. If you rotate a mutilated gear with half its teeth missing, whose teeth mesh with a full spur gear at one rotation every 30 seconds, the spur gear will turn for 15 seconds, and then stay put for 15 seconds. In this way you can turn continuous rotational motion into discrete rotational motion, meaning that the input shaft turns continuously and the output shaft turns a little, and then stops, then turns again, then stops again, repeatedly.
Although rare in industry, non-circular gears are pretty interesting mechanisms. The diameter of the gears where they are contacting each other change as the gears rotate, so the output speed of the system oscillates as the gears rotate. Non-circular gears can take almost any shape. If the two axes constraining the gears are fixed, then the sum of the radii of the gears at the point where they mesh should always be equal to the distance between the two axes.
A ratchet is a fairly simple mechanism that only allows a gear to turn in one direction. A ratchet system consists of a gear (sometimes the teeth are different than the standard profile) with a small lever or latch that rotates about a pivot point and catches in the teeth of the gear. The latch is designed and oriented such that if the gear were to turn in one direction, the gear could spin freely and the latch would be pushed up by the teeth, but if the gear were to spin in the other direction, the latch would catch in the teeth of the gear and prevent it from moving.
Clutches are mechanisms found primarily in cars and other road vehicles, and they are used to change the speed of the output shaft, as well as disengage or engage the turning of the output shaft. A clutch mechanism involves at least two shafts, the input shaft, driven by a power source, and the output shaft, which drives the final mechanism. As an example, I'll explain a simple 2 gear clutch mechanism, referencing the image above. The input shaft would have two gears on it of different sizes (the two blue gears on the top shaft), and the output shaft contains two gears that mesh with the gears on the input shaft (the red and green gears), but can rotate freely around the output shaft, so they do not drive it. A clutch disc (the blue grooved piece in the middle) sits between the two gears, rotates with the output shaft, and can slide along it. If the clutch disc is pressed against the red gear, the output shaft would engage and turn at the speed defined by the gear ratio of that set of gears (3:2). If the clutch disc presses against the green gear, the output shaft drives at a different gear ratio, defined by that gear set (2:3). If the clutch disc sits between the two gears, then the output shaft is in neutral and is not being driven.
A gear differential is a pretty interesting mechanism involving a ring bevel gear and four smaller bevel gears (two sun gears and two planet gears that orbit around them), acting sort of like a planetary gearbox. It is used mostly on cars and other vehicles, because it has one input shaft that drives two output shafts (which would connect to the wheels), and allows for the two output shafts to spin at different velocity if they need to. It ends up that the average of the rotational velocities of each output shaft always has to equal the rotational velocity of the ring gear.
I'll explain how a differential works using the images above. The input shaft spins the yellow bevel gear, which spins the green bevel ring gear. A carriage is fixed to the ring gear that spins with it. Both the carriage and the ring gear rotate around (but do not directly turn) the axis of the red output shafts. The two blue bevel gears turn in big circles around the central axis, the axis the output shafts go through. Lets imagine this differential sits with the output shafts connected to the back two wheels of a car. If the car is going straight, the two blue bevel gears will spin around the output shafts, because of the rotation of the carriage, without rotating about their own axis. Their teeth will push the two red gears at the same speed, each connected to their respective output shafts. Thus, the wheels spin at the same speed and the car goes straight. You'll notice the blue gears have the ability to spin about their axis though, which is important to the mechanism. Keep reading!
Should the car turn, then the two wheels will want to spin at different speeds. The inner wheel will want spin at a velocity slower than the outer one because it is closer to the center point of the car's turn. If the two wheels were connected on the same shaft, then the car would have a difficult time turning: one wheel would want to spin slower than the other, so it would drag. With the differential gear mechanism, the two shafts not only allow the wheels to spin at their own speeds, but also are still powered by the input shaft. If one wheel is spinning faster than the other, the blue planetary bevel gears just rotate about their axes instead of staying fixed. Now, the planetary gears are both rotating about their axes and about the output shafts (because of the carriage), thus powering both wheels, but allowing one to spin faster than the other. 2ff7e9595c
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