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THE EMERGENCE AND DEVELOPMENT OF THE AUTOMATIC GEAR.
Rakhmonchayev Dilmurodjon Tulamirzayevich
Department of Labor Protection Assistant
Andijan state technical institute
+998 979910200
Annotation.
In this work, the emergence of the automatic transmission (AUQ), its
design structure, and technological production components were studied. The historical
development of additional mechanical transmission systems in automobiles is analyzed, and the
evolutionary processes up to modern electronically controlled automatic transmissions are
highlighted. In the work, consider the power, creation of an automatic transmission, the
operating principle, and technological achievements of different generations. The industry will
reveal the importance of innovative solutions in the automotive industry in this area and will also
take a look at the trends in the production of automatic transmissions.
Keywords
: Automatic transmissions, Transmission system, AT (A), multiple automatic
transmission, Hydraulic, Planetary transmissions, Torque converter, History of the automotive
industry, Transmission system evolution, Automatic transmission.
Introduction.
Mechanical Gearbox (MG) synchronizers provide ease of gear shifting in various vehicle
speeds, but in this case require a high degree of driver attention. The possibilities of automatic
transmission are wide to free drivers from such inconveniences and moral burdens, as well as to
improve the convenience of driving[1].
In this regard, General Motors' initial automatic transmission was 4-speed, controlled by
an automatic system, and equipped with a hydraulic coupling.
It evolved over time into a hydrotransformer, making the connection more smooth and
efficient.[2]
Along with turbine and pump wheels, the hydrotransformer also has a reactor, which
transmits the torque from the engine very smoothly through the working fluid - oil. In this case,
the magnitude of the torque changes automatically (depending on the speed of the vehicle and
road conditions). The pump wheel of the AUQ is connected to the engine crankshaft, and the
turbine wheel to the drive shaft of the UQ (Fig. 1) [3].
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Figure 1. Automatic gearbox
At the same time, AUQs have the following drawbacks:
A vehicle equipped with a gearbox has higher fuel consumption compared to a vehicle
equipped with a MUQ;
A vehicle equipped with a gearbox can only be towed in exceptional cases with strict observance of
all safety measures. In such situations, it is advisable to use the services of an evacuator[4].
Sequential-type AUQ
Sequential-type automobile transmissions differ little from mechanical UQs. In it, the
gears are automatically controlled by a special hydromechanical system. The control is
controlled by the machine's electronic system, and there is no need for a clutch pedal.
Sequentiality (sequential, Eng.) in a transmission implies a strict sequence of gear transmissions,
i.e., transmissions must be driven from bottom to top and vice versa in a strict sequence across
each step [5].
Such AUQs are also widely used in tractors, since they use multiple transmissions with a
wide range of torque changes [6].
Robotic (automatically controlled manual transmission) UQ
The structure and operating principle of the robotic UQ largely correspond to the
technical characteristics of the standard mechanical transmission. It also has three main shafts
(driven, driven, and intermediate), with similar gears and gear ratios. The term "robot" means
that all processes are controlled by special devices - "servo drives" and "actuators," which
perform the function of connecting and disconnecting the transmission at the required time.
Control of these processes is carried out using a special electronic unit, which transmits control
commands to an electric motor with a reducer or hydraulic drive (Fig. 2) [7].
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Figure 2. Automatically controlled manual transmission
A driver of a vehicle equipped with a robotic UQ can hand over automatic control of the vehicle,
relying on a computer, or manually control it using a lever or leaf-shaped selector placed under
the steering wheel to switch gears [8].
Disadvantages of a robotic UQ:
in difficult driving conditions, the clutch is not smoothly controlled, as frequent gear changes cause
discomfort;
The prolonged separation of the driving and driven discs during transitions from one gear to another
reduces the engine's flexibility and leads to a slight decrease in the machine's speed [9].
Robotic UQ equipped with two clutches
To eliminate the aforementioned shortcomings, the robotic UQ was equipped with two
clutches. The use of such a design has significantly increased the capabilities of the unit, i.e.,
along with the currently operating drive, it is possible to select the drive that needs to be
connected next and connect it in advance (Fig. 3).
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Figure 3. Robotic gearbox equipped with two gears
As a result, the transition time from one gear to another is significantly reduced, the
maneuverability of the vehicle increases, and its control becomes more convenient.
The variator type of transmission is considered stepless. The worm of such a
transmission has the ability to smoothly transmit torque (Fig. 4).
In essence, a variator is a stepless "automatic" that does not have a constant transmission ratio.
Figure 4. Variator AUQ
As an automatic transmission unit, the variator has the following advantages:
there are no gears and shafts in its design, since it is not necessary to systematically change a certain
value of the torque by disconnecting the engine from the transmission;
it does not have transition stages with a given gear ratio;
The torque transmitted to the drive shaft through the variator constantly changes depending on how
the wedge-shaped belt is positioned relative to the conical pulleys;
The smoothness and softness of the transmission, equipped with a variator, are practically ideal.
Despite the fact that these achievements of variators are revolutionary designs in the
automotive industry, they are currently used in low-power vehicles. Their main disadvantages
are limited resources (about 200 thousand
km
) and high cost of maintenance.
Tiptronic
The term "Tiptronic" should be used in relation to the emergence of its functional
capabilities through the installation of an additional device in the UQ's design, and not some kind
of UQ (Fig. 5) [10].
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Figure 5. Tiptronic Function AUQ Control Lever
The standard form of the AUQ used in motor vehicles does not allow for the control of some
dynamic parameters, such as high (rapid) acceleration, engine braking, or forced transition to a
low gear, etc. In these cases, the "typtronic" function solves these problems through an auxiliary
speed control system associated with electronic control using a lever selector (Fig. 6).
Conclusion.
Modern automatic transmissions are produced in various types (hydraulic, robotic,
variable) and have such advantages as fuel efficiency, smooth operation, and accuracy in gear
shifting. Their development was an important stage in the automotive industry, which not only
created convenience for drivers, but also gave impetus to the overall advancement of automotive
technology.
In general, the creation and improvement of automatic transmissions have served to
increase the ergonomics and safety of vehicles and have become one of the integral technologies
in modern automotive manufacturing.
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Volume 15 Issue 08, August 2025
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6.995, 2024 7.75
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