Gear operation

Introduction

In a manual transmission for a rear-wheel drive vehicle, the gear train is
built up on three shafts. The input shaft extends from the front of the transmission.

An external parallel-splined section engages with internal splines on the clutch-driven plate.A main-drive gear is an integral part of the shaft. It meshes constantly with a mating gear on a counter-shaft which has a number of gears
formed on it.These gears mesh with mating gears on the mainshaft, or output. These mainshaft gears are supported on bearings on the shaft. They can rotate
without turning the output.


Each mainshaft gear has an external toothed section on one side. The
teeth face an internally-toothed engagement sleeve located on a central
hub, which is itself splined to the mainshaft. The engagement sleeve can slide in either direction to engage the external teeth on the appropriate gear. This locks the gear through the sleeve and hub, to the mainshaft.

The engagement sleeve can slide in either direction to engage the external
teeth on the appropriate gear. This locks the gear through the sleeve and
hub, to the mainshaft.Before engagement of the components occurs, a synchromesh devicebetween the sleeve and gear synchronizes them.
The gears constantly in mesh, have their teeth cut on a helix, at an angle
to the gear center line.This reduces gear noise and distributes load more evenly, as several teeth are in contact at any one time. Teeth on the reverse idler are normally straight cut or spur gears, cut parallel to the gear center line.
When reverse is selected, this connects the reverse idler with mating
gears on the countershaft and mainshaft. The reverse idler rotates on a plain shaft fixed in the casing. It transfers the drive from one shaft to the other, and reverses the direction of rotation of the mainshaft.

Differential

 

Introduction

Car wheels spin at different speeds, especially when turning . wheel travels a different distance through the turn, and that the inside wheels travel a shorter distance than the outside wheels. For the non-driven wheels 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 tire would have to slip. With modern tires 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.

How Differential Work

The drive shaft ends in a pinion gear inside the differential. When the drive shaft turns, the pinion drives a ring gear that is part of the differential housing, so that both housing and ring gear rotate together. Inside the housing are two pinion gears and two side gears; each side gear is connected, via an axle, to a drive wheel. When the car drives straight ahead and the axle shafts turn at the same speed, the differential housing rotates, but no differential action occurs. When the car negotiates a turn, however, the differential must compensate for the difference in distance traveled by the drive wheels. The opinions roll around the side gears, allowing the inside wheel to turn more slowly and the outside wheel to turn more slowly and the outside wheel to turn faster.

1.       The differential on a vehicle, be it a front- or rear-wheel drive, is the final gear reduction for the transmission. It not only reduces the ratio, but supplies the engine power to the drive wheels. The picture above illustrates the gear locations within the carrier.

2.       The power from the engine is transmitted through the pinion gear at the top. The pinion gear turns the large ring gear, which changes the direction of the power 90 degrees so that it can be transmitted to the wheels. The drawing depicts the axles and tires on both sides. These axles have splines on the ends, and are inserted into the side gears in the differential (marked in yellow). The axles are held in the side gears by the splines so that the side gear and axle move as one.

3.       The spider gears are the small gears in the top and bottom of the chunk. They are in between and mesh with both side gears. When the vehicle is going straight, both axles turn at the same speed and the spider gears do not rotate. All they do is lock up both axles so they turn at the same speed. When the vehicle turns, the spider gears will rotate, allowing one axle to turn at a different speed than the other--hence the name, "differential."

4.       This is a depiction of an open differential, which is commonly found in most vehicles. They are quite trouble-free, but do have one disadvantage. On a dry road with good traction, the power is evenly applied to both wheels. When one of the tires hits ice or a slippery surface, it begins to spin and the majority of torque is directed to the spinning wheel, leaving very little for the wheel with the good traction. This is how vehicles can get stuck in snow or mud.

5.       Another type of differential is the limited slip differential, which is an option on most new cars. It has a distinct advantage by having a set of clutches and springs within the differential. Their function is to apply pressure to the side gears should one of the tires begin to slip. By applying pressure to the opposite wheel from the one spinning, it allows for more torque to be applied to the wheel with traction. If is far superior to the open differential when it comes to traction in bad weather.