CLUTCHES

A clutch is a mechanical device which provides for the transmission of power (and therefore usually motion) from one component (the driving member) to another (the driven member). The opposite component of the clutch is the brake.

Clutches are used whenever the ability to limit the transmission of power or motion needs to be controlled either in amount or over time. Clutches control whether automobiles transmit engine power to the wheels.

In the simplest application clutches are employed in devices which have two rotating shafts. In these devices one shaft is typically attached to a motor or other power unit (the driving member) while the other shaft (the driven member) provides output power for work to be done. The clutch connects the two shafts so that they may be locked together and spin at the same speed (engaged), locked together but spinning at different speeds (slipping), or unlocked and spinning at different speeds (disengaged).
Friction disk clutches generally are classified as "Push Type" or "Pull Type" depending on the location of the pressure plate fulcrum points. In a pull type clutch, the action of pressing the pedal pulls the release bearing, pulling on the diaphragm spring and disengaging the vehicle drive. The opposite is true with a push type, the release bearing is pushed into the clutch disengaging the vehicle drive. In this instance, the release bearing can be known as a thrust bearing.


 

http://en.wikipedia.org/wiki/Clutch

http://www.8thcivic.com/forums/mechanical-problems-technical-chat/201490-2nd-gear-grind-theory-please-read-7.html

http://www.carcraft.com/techarticles/clutch_basics/photo_06.html

C.V JOINTS & DRIVESHAFTS

 

C.V JOINTS

 

All front-wheel drive cars have Constant Velocity joints or CV joints on both ends of the drive shafts (half shafts); the inner CV joints connect the drive shafts to the transmission and the outer CV joints connect the drive wheels to the drive shafts (see the picture). Many rear- and four-wheel drive cars and trucks have CV joints as well. The CV joints are needed to transfer the torque at a constant speed to the steered wheels as well as to accommodate up and down motion of the suspension.

A CV joint is packed with a grease and sealed tight by the rubber or plastic boot. A CV joint doesn't need any maintenance and can last very long, as long as the protective CV joint boot is not damaged.

There are two most commonly used types of CV joints: a ball-type and a tripod-type. Ball-type CV joints are commonly used on the outer side of the drive shaft, while the tripod-type CV joints mostly used on the inner side.

http://www.samarins.com/glossary/cv_joint.html

http://blog.micksgarage.ie/post/MicksGarage-Tuesday-Tip-Common-issues-with-CV-joints.aspx 

http://forums.nasioc.com/forums/showthread.php?t=1377786

DRIVESHAFT

A driveshaft, also referred to as a propeller shaft, is a mechanical component that sends torque, or the force of motion, to other car parts. Driveshafts can connect to other components that work together in a drive train, or system used to create and transmit power to a surface, such as a road.

A driveshaft's main purpose is to transmit torque between multiple car components. Driveshafts typically receive torque from the transmission and engine and carry it over to the other end of the car. Two other, shorter driveshafts then typically send torque to the wheels.

Driveshafts are designed to handle shear stress, which is the force applied parallel to material. Drive shafts also handle torsion, or the twisting of an object resulting from torque. Driveshafts hold and transfer such energy without adding significant inertia, which is the resistance of these forces. 

http://www.ehow.com/facts_7177571_purpose-drive-shaft_.html#ixzz1P6MDN5lh

http://www.dimensionsguide.com/drive-shaft-dimensions/

Differentials

The differential has three jobs:

1. To transfer the drive from the drive shaft to the wheels

2. To act as the final gear reduction in the vehicle, slowing the rotational speed of the transmission one final time before it hits the wheels

3. To transmit the power to the wheels while allowing them to rotate at different speeds (This is the one that earned the differential its name.)

Car wheels spin at different speeds, especially when turning. Each wheel travels a different distance through the turn, and that the inside wheels travel a shorter distance than the outside wheels. Since speed is equal to the distance traveled divided by the time it takes to go that distance, the wheels that travel a shorter distance travel at a lower speed. Also the front wheels travel a different distance than the rear wheels.
 

For the non-driven wheels on your car -- the front wheels on a rear-wheel drive car, the back wheels on a front-wheel drive car -- this is not an issue. There is no connection between them, so they spin independently. But the driven wheels are linked together so that a single engine and transmission can turn both wheels. If your car did not have a differential, the wheels would have to be locked together, forced to spin at the same speed. This would make turning difficult and hard on your car: For the car to be able to turn, one tyre would have to slip. With modern tyres and concrete roads, a great deal of force is required to make a tire slip. That force would have to be transmitted through the axle from one wheel to another, putting a heavy strain on the axle components and gearbox.

http://www.howstuffworks.com/differential.htm

http://www.team-bhp.com/forum/attachments/4x4-vehicles/301364d1267847120-mpfi-gypsy-king-bought-mayapuri-differential-diagram.jpg

MANUAL TRANSMISSION

We are currently studying about front wheel drive gear boxes.

The gearbox I was working on today was never opened up before. The external physical condition of the gearbox looked very good, it had no damage or cracks.

When I opened the rear case, I saw the fifth gear driver and driven gear. I unbolted the nuts on the gears. Now, the gears did not come out easily. I used a three legged puller to remove the gear from its place.

I opened all the remaining bolts, and also i had to remove the plunger from the selector interlock mechanism. A few bolts inside the bell housing had to be removed as well for the gearbox body assembly to dismantle fully apart.

Gearbox Operation

In the front wheel drive gearbox, there are two main shafts, the primary and secondary (Input and output shafts). 

When for example, the first gear is selected, the 1st & 2nd gear shfit fork which is holding the 1st & 2nd syncro sleeve is moved over the 1st gear driven dog teeth which than connects the 1st gear driver gear.

The Synchromesh

A synchro is a device that allows the dog gear to come to a speed matching the helical gear before the dog teeth attempt to engage. In this way, you don’t need to ‘blip’ the throttle and double-clutch to change gears because the synchro does the job of matching the speeds of various gearbox components for you.

Types of gears

The most basic type of gear is called a spur gear, and it has straight-cut teeth, where the angle of the teeth is parallel to the axis of the gear. Wider gears and those that are cut for smoother meshing are often cut with the teeth at an angle, and these are called helical gears. Because of the angle of cut, helical gear teeth have a much more gradual engagement with each other, and as such they operate a lot more smoothly and quietly than spur gears. Gearboxes for cars and motorbikes almost always use helical gears because of this.