Manual Drive Trains and Axles
Introduction
An automobile can be divided into four major systems or basic components : 1 the engine, which serves as source of power: 2) the power train, or drive, which transmits the engine’s power to the car’s wheels ; 3) the chassis, which supports the engine and body and includes the brake, steering, and suspension system;
and 4) the car’s body, interior, and accessories, which include the
seats, heater and air conditioner, lights, windshield wipers, and other
comport and safety features.
Basically,
the drive train has four primary purposes: to connect and disconnect
the engine’s power to the wheels, to select different speed rations, to
provide a way to move the car in reverse, and to control the power to
drive wheel for safe turning of the automobile. The main components of
the manual drive train are the : clutch, transmission, differential, and
drive axles ( figure 1-1). The exact components used in vehicle’s drive
train depend on whether the vehicle is equipped with front-wheel drive,
rear-wheel drive, or four-wheel drive.
Today,
most cars are front-wheel drive ( FWD). Power flow through the drive
train of FWD vehicles passes though the clutch or torque converter,
through the transmission, and then moves to front differential, the
driving axles, and onto the front wheels. The transmission and
differential are housed in a single unit ( figure 1-2) called a trans
axle.
Some
large and many performance cars are rear-wheel drive (RWD). Most
pick-up trucks and many SUV's are also RWD vehicles. Power flow in a
RWD vehicle passes through the clutch or torque converter, transmission,
and the drive line ( drive shaft assembly ). Then it goes through the
rear differential, the rear-driving axles, and onto the rear wheels.
Four-wheel
drive ( 4WD ) or all-wheel drive (AWD) vehicles combine features of
both rear- and front-wheel drive systems so power can be delivered to
all wheel all the time or when the conditions or driver selects
two-wheel or four-wheel drive. Normally, a 4WD pi Normally, a 4WD pi
Normally, a 4WD pickup or full-size SUV has 4WD; the drive train is
based on a RWD vehicle modified to include a front drive axle and
transfer case. When a smaller SUV or car has AWD or 4WD, the drive
train is modified system. Modification include a rear drive axle and
assembly that transfers some of the engine’s power to the rear drive
axle.
There
are two sets of gear in the drive train: the transmission and the
differential. The transmission allows the gear ratio to change and the
differential unit changes the power output from the transmission and
allows the drive wheels to rotate at different speeds during turns; this
prevents tire scuffing. Through the use of different gear ratios,
torques is multiplied.
