Semi-automatic Gearbox
The semiautomatic Gearboxes are also known as “clutch less manual
transmissions” or “automated manual transmissions”, “e-gears”,
or “paddle shift gearboxes” In semiautomatic gear boxes, there are
sensors, processors and actuators. These things help in shifting the gears
on the command of the drivers. The requirement of the clutch pedal is taken
off in semiautomatic gearbox. Otherwise, it is needed to a driver to depress
the clutch pedal before changing the gear. In semiautomatic gearbox, the
clutch is put into action by electronic action which can again exactly
adjust the mechanical rotation and timing of the gears. This makes them more
quicker, accurate and smoother. The first design of the semiautomatic
gearbox system was designed by the European Automobile manufacturer. The
objective behind the designing purpose was to avail a better driving
experience specially in those cities where high and frequent road-jam
problem is present.
Types of Semiautomatic Gearboxes
There are two most important types of semiautomatic gearboxes present.
These two types are:
A Twin-Clutch Gearbox
A Twin-Clutch Gearbox is also called as Dual Clutch Transmission (DTC).
This is a kind of semi-automatic gearbox with disperse clutches for even as
well as odd number of gears. The external clutch causes the movement of
gears 1, 2, and 5 and also the reverse gear. The internal clutch is
responsible for the movement of gears 2, 4, and 6. By applying the engine's
torque to one clutch just disconnecting the torque from another clutch,
shifts can be a completed. While driving the car in the even gear, the odd
gear can be moved which is selected by the synchronizers. The opposite one
is also possible. The configuration of DTC's makes the shift faster even
than the formula one cars and other single-clutch automated-manual
gearboxes. The torque converter is removed from a twin-clutch gearbox which
is the prime source of chronic loss in the traditional automatic gearboxes.
In the market, the available twin-clutch gearboxes use wet multi-plate
clutches. These wet multi-plate clutches are also used in the traditional
automatic gearboxes.
Saxomat Semiautomated Gearbox
Saxomat is a type of automatic clutch which was found on Fiat 1800,
Borgward, Opel, NSU, BMW, DKW, Volkswagen etc., as an option. Different
automobile companies sold them in different names. Like Opel sold them as
Olymat etc. In 1990's, these Saxomat was appeared in the market in the
Santroric cars without having any clutch plates. Sexomat Semiautomatic
gearboxes contained two integrated but independent sub-system. These two
subsystems are: centrifugal clutch and servo clutch. The first clutch system
i.e. Centrifugal clutch system is integrated upon some specific RPM engines
by centrifugal force. It acts inside the clutch on the spinning weight just
like the centrifugal governor. The another sub-system, servo clutch uses an
electric switch that furnished vacuum through an actuator valve to a
reservoir which freed the clutch from engagement. The auto disengagement is
taken place on the clutch as soon as the accelerator is freed out or the
gear shift lever is touched.
