Differential and Open differential

Differential controls the speed of the left and right wheels on your vehicle.

It allows them to rotate at different speeds while making turns, as the outer wheel path is longer in distance than the inner wheel.

Types of differentials:1)open differentials

                                  2)Limited-slip differentials

                                  3)locking differentials

Open Differential:

Open differentials have a few essential components, illustrated below. The input pinion gear is the gear that is driven from the drivetrain - typically the output shaft from the transmission. It drives the ring gear which, being larger, is what gives that final gear reduction I mentioned. Attached to the ring gear is the cage, containing two captive pinion gears that are intermeshed with the two output pinion gears, one connected to each axle. The captive pinions are free to rotate how they wish.

As the input pinion spins, it meshes with the ring gear. The ring gear spins, spinning the cage and the two captive pinions. When the vehicle is travelling in a straight line, neither drive pinion is trying to spin any differently from the other, so the captive pinions don't spin and the turning of the ring gear is translated directly to both drive pinions. These are connected to the driveshafts to the wheels, so effectively, the ring gear spins the wheels at the same speed that it is turning. When the vehicle starts to turn a corner, one of the wheels is going to want to spin more quickly than the other. At this point, the captive pinions come into play, allowing the two drive pinions to spin at slightly different speeds

How differential works:

                                         

references:     www.carbible.com

                       www.learnengineering.com

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Types of gears

1. Spur Gear
2. Helical Gear
3. Herringbone Gear
4. Bevel Gear
5. Worm Gear
6. Rack and Pinion
7. Internal and External Gear
8. Face Gear
9. Sprcokets

1. Spur Gear:Spur gears have straight teeth and are parallel to the axis of the wheel. Spur gears are the most common type of gears. The advantages of spur gears are their simplicity in design, economy of manufacture and maintenance, and absence of end thrust. They impose only radial loads on the bearings.Spur gears are known as slow speed gears. If noise is not a serious design problem, spur gears can be used at almost any speed.
   
2. Helical Gear:Helical gears have their teeth inclined to the axis of the shafts in the form of a helix, hence the name helical gears.
   
   These gears are usually thought of as high speed gears. Helical gears can take higher loads than similarly sized spur gears. The motion of helical gears is smoother and quieter than the motion of spur gears.
   
   Single helical gears impose both radial loads and thrust loads on their bearings and so require the use of thrust bearings. The angle of the helix on both the gear and the must be same in magnitude but opposite in direction, i.e., a right hand pinion meshes with a left hand gear.
   
3. Herringbone Gear:Herringbone gears resemble two helical gears that have been placed side by side. They are often referred to as "double helicals". In the double helical gears arrangement, the thrusts are counter-balanced. In such double helical gears there is no thrust loading on the bearings.
   
4. Spiral Bevel gears: In these Spiral Bevel gears, the teeth are oblique. Spiral Bevel gears are quieter and can take up more load as compared to straight bevel gears.
   
5.          Worm Gear- Worm gears are used to transmit power at 90° and where high reductions are required. The axes of worm gears shafts cross in space. The shafts of worm gears lie in parallel planes and may be skewed at any angle between zero and a right angle.In worm gears, one gear has screw threads. Due to this, worm gears are quiet, vibration free and give a smooth output.Worm gears and worm gear shafts are almost invariably at right angles.
   
6.           Rack and Pinion- A rack is a toothed bar or rod that can be thought of as a sector gear with an infinitely large radius of curvature. Torque can be converted to linear force by meshing a rack with a pinion: the pinion turns; the rack moves in a straight line. Such a mechanism is used in automobiles to convert the rotation of the steering wheel into the left-to-right motion of the tie rod(s). Racks also feature in the theory of gear geometry, where, for instance, the tooth shape of an interchangeable set of gears may be specified for the rack (infinite radius), and the tooth shapes for gears of particular actual radii then derived from that. The rack and pinion gear type is employed in a rack railway.
   
7.    Face Gears- Face gears transmit power at (usually) right angles in a circular motion. Face gears are not very common in industrial application.
   
8. Sprockets-Sprockets are used to run chains or belts. They are typically used in conveyor systems.
   ref:www.mech4study.blogspot.com

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Types of clutches

Single Plate Clutch:

The diagram shows the pressure plate pulled back by the release levers against the compression springs; so that the friction linings on the clutch plate are free of flywheel and pressure plate. The flywheel rotates without driving the clutch plate and hence the shaft.

When the pressure of the thrust race is released the compression springs are free to move the pressure plate to the left bringing it in contact with the clutch plate.

The pressure plate moves to the left, sliding the clutch plate on its splined hub, along the driven shaft until the friction lining touches the flywheel.

The compression springs now cause the linings to be gripped between the pressure plate and the flywheel and the friction between the linings and flywheel and pressure plate causes the clutch plate to revolve, turning the driven shaft.

Multi plate clutch:

When a great amount of torque is to be transmitted, instead of single plate a number of friction plates are employed. This increases the number of mating friction surfaces, hence it is called multiplate clutch.

These clutches are used in heavy commercial vehicles, racing cars and motor cycles for transmitting high torque

cone clutch:It consists of a flywheel and a cone mounted on driving and driven shafts respectively. The shape of the side of the flywheel facing the cone is as to accommodate the cone readily when the clutch is engaged. The surfaces of contact are lined with the friction lining (Asbestos, leather etc.). The cone can be disengaged from flywheel by mechanism which operates in the groove of the cone.

centrifugal clutch:A centrifugal clutch is a clutch that uses centrifugal force to connect two concentric shafts, with the driving shaft nested inside the driven shaft. It engages more at higher speeds.

The input of the clutch is connected to the engine crankshaft while the output may drive a shaft, chain, or belt. As engine revolutions per minute increase, weighted arms in the clutch swing outward and force the clutch to engage. The most common types have friction pads or shoes radially mounted that engage the inside of the rim of a housing. On the center shaft there are an assorted number of extension springs, which connect to a clutch shoe. When the central shaft spins fast enough, the springs extend causing the clutch shoes to engage the friction face. It can be compared to a drum brake in reverse.

ref:www.mech4study.blogspot.com

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Clutch and its compnents

CLUTCH:A clutch is a mechanical device that engages and disengages the power transmission, especially from driving shaft to driven shaft. It is located between flywheel and gearbox.

1)Primary components

   Flywheel

   Clutch disc

   Pressure plate

   Release (Throw out) bearing

2)Secondary components 

   Pilot bearing 

   Release fork 

   Slave cylinder

        

    

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Transmission system

Transmission system:Transmission is the mechanism that transmits the power from the engine crankshaft to the wheels, providing the variable speed and torque at the road wheels as per the requirement

Types of transmission systems:

1)Manual Transmission

2)Fully-Automatic Transmission

3)Semi-Automatic Transmission

4)Continuously Variable Transmission

1)Manual Transmission:In case of the manual transmission system, the vehicle is driven with the assistance of gearshift and clutch. The other components, which are used in this process, are flywheel, pressure plate and ring gears.

2)Automatic transmission:In case of the automatic transmission system, the gears are changed automatically corresponding with the vehicle's speed. The basic components essential for this process are modulator, torque converter, planetary gears, governor, computer, seals and hydraulic designs.

3)continuous variable transimmision:The most basic CVT has two variable pulleys and either a steel-core rubber pull-belt or a steel alloy push-belt. One pulley is connected to the flywheel and the other to the gearbox output shaft. The belt loops around between the two. On simple scooter-type CVTs, the pulleys change geometry simply by rotational forces - the faster the engine pulley spins, the more it closes up and the faster the output pulley spins, the more it opens out. In automotive applications, the geometry of the pulley is governed by a hydraulic piston connected to the ECU. The pulley itself is basically a splined shaft with a pair of sliding conical wedges on it (called 'Sheaves').

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