Here is the slide of Fluid coupling and Torque Converter.. It is a part of Hydraulic Physics...

1. FLUID COUPLING
AND
HYDRAULIC TORQUE
CONVERTER
By
VIKASH KUMAR
And
SHIVAM NEGI

2. CONTENTS
• 1) Introduction of HYDRAULIC COUPLING and HYDRAULIC TORQUE
CONVERTER
• 2) Construction of HYDRAULIC COUPLING and HYDRAULIC TORQUE
CONVERTER
• 3) Working of HYDRAULIC COUPLING and HYDRAULIC TORQUE
CONVERTER
• 4) Efficiency of HYDRAULIC COUPLING and HYDRAULIC TORQUE
CONVERTER
• 5) Uses of HYDRAULIC COUPLING and HYDRAULIC TORQUE
CONVERTER

3. What is a Fluid Coupling?
• A fluid coupling or hydraulic coupling is a device which is employed
for transmission of power from one shaft to another through a liquid
medium.
• It has no mechanical connection or face to face contact.
• The magnitude of input and output torques are equal.

4. Histoty
• The fluid coupling originates from the work of Dr. Hermann fottinger ,
who was the chief designer at the AG Vulcan Works in Stettin.
• Hermann Fottinger (born 9 February1877 in Nuremberg; died 28 April
1945 in Berlin) was a German engineer and inventor.

5. Construction of a Fluid Coupling
It consists of the following two rotating elements
(i) Pump impeller. It is attached to a driving shaft
of the prime mover which may be an I.C.engine,a
steam engine or an electric motor
(ii) Turbine runner. It is attached to a driven
shaft.
Both the above units are enclosed in a
single housing filled with a liquid,usually oil, because
of its lubricating power ,availability and stability.This
oil impeller to the turbine runner.There is no direct
contact between the driving and driven parts.

6. Working of a Fluid Coupling
• As soon as the prime mover starts rotating, the pump impeller also
starts rotating and throws the oil outward by centrifugal action.The oil
then enters the turbine runner and exerts a force on the runner
blades.The magnitude of the torque increases with an increase in the
speed of the driving shaft and eventually when this torque overcomes
the inertia effects, the turbine runner and the driven shaft begin to
rotate.The oil from the runner then flows back into the pump
impeller,thus a complete hydraulic(oil) circuit is established.

8. Efficiency of HYDRAULIC COUPLING
• The efficiency (ŋ) of the hydraulic coupling is defined as the ratio of
power output to power input..
Power output (𝑝0) 𝑇 𝑡 𝑤𝑡 𝑤𝑡
= =
Powere Input (𝑝𝑖) 𝑇𝑝 𝑤 𝑝 𝑤 𝑝
Where,
𝑇 𝑡=Torque on the turbine or driven shaft’2’
𝑤𝑡=Angular speed of the turbine shaft or driven shaft ‘2’
𝑇𝑝 = Torque on the pump or driving shaft ′
1′
𝑤 𝑝= Angular speed of the turbine shaft or driven shaft’1’

9. Uses of hydraulic coupling
• Although a hydraulic or fluid coupling has a low value of transmission
efficiency when compared to mechanical coupling,yet it is widely
used in the following fields:
(i) Automobiles, marine engines, rope way cable drive units and such
other application where driven shaft is required to run at a speed close
to that of the driving shaft:
(ii) These couplings are particularly useful where large initial loads
are involved and smooth shock-free operations are
requied.
It has been used in automobiles
transmissions as an alternative to a mechanical Clutch

10. Advantages and Disadvantages
Advabtages
1) Makes it easy the gently
accelerate the driven
machines
2) Limites torques,Provied load
sharing,dampen torque
vibrations
3) During start up will reduce
current draw on your electric
moter by 33%
Disadvantages
1) Under stall conditions all of
the engines power would be
dissipated in the fluid coupling
as heat leading to damage
2) Fluid coupling can not develop
output torque when the input
and output angular velocities
are indentical

11. Materials
• Fluid couplings are relatively simple components to produce.For
example,the trubines can be aluminium castings or steel
stampings,and the housing can also be a casting or made from
stamped or forged steel.

12. What is a HYDRAULIC TORQUE CONVERTER
• Hydraulic torque converter is a device used for transmitting increased
or decrease power from one shaft to another.
• A variable torque is impressed on the driven member without the use
of a gear train or clutch.
• The torque at the driven shaft may be increased about five times the
torque available at the driving shaft with an efficiency of about 90%

13. Construction of HYDRAULIC TORQUE
CONVERTER
• The hydraulic torque converter consists of
the following:
1) Pump impeller coupled to the driving
shaft,
2) Turbine runner coupled to the driven
shaft,and
3) Stationary/fixed guide vanes(also known
as reaction members) Provided between
the impeller and the turbine runner.

14. Working of HYDRAULIC TORQUE
CONVERTER
• The liquid flowing from the pump impeller to turbine runner exerts a
torque on the stationary guide vanes which changes the directions of
liquied,thereby making possible the transformation of torque and
speed.Thus by suitably designing the stationary guide vanes the
torque transmitted to the driving unit can be either increase or
decrease.
• The torque relationship is given as:
𝑇𝑡 = 𝑇𝑝 + 𝑇𝑣
Where,
𝑇𝑝=Torque of pump impeller
𝑇𝑣=variation of torque caused by fixed guide vanes..

16. Efficiency of HYDRAULIC TORQUE
CONVERTER
• The efficiency (ŋ) of the hydraulic torque is defined as the ratio of power output
to power input..
Power output (𝑝0) (𝑇 𝑝 𝑇𝑣)𝑤𝑡
=
Powere Input (𝑝𝑖) 𝑇𝑝 𝑤 𝑝
Where,
𝑇𝑣=variation of torque caused by fixed guide vanes..
𝑤𝑡=Angular speed of the turbine shaft or driven shaft
𝑇𝑝 = Torque on the pump or driving shaft
𝑤 𝑝= Angular speed of the turbine shaft or driven shaft

17. Uses of HYDRAULIC TORQUE
CONVERTER
• Automatic transmissions on automobiles, such as cars, buses, and
on/off highway trucks.
• Forwarders and other heavy duty vehicles.
• Marine propulsion systems.
• Industrial power transmission such as conveyor drives, almost all
modern forklifts, winches, drilling rigs, construction equipment,
and railway locomotives.

18. What is a difference and similarities between a fluid
coupling & a fluid torque converter?
• Both are used for same purpose that is transmitting power from one shaft
to another but the Torque converter has a stator between the turbine and
the impeller which multiplies the torque about 5 times of the driving shaft
to the driven shaft.
• fluid coupling consists of two members the driving and driven member as
shown. The driving member is attached to the engine and the driven
member to the transmission shaft.
• In fluid coupling the two members do not have any direct contact.
• The construction of fluid torque converter is very similar to that of the
fluid flywheel expect for an additional stationary member called stator.
• In fluid torque converter all the members have blades or vanes of specific
shape.Even though the construction is similar, the operation is not.
• The fluid flywheel transmits the same torque as given as given to it by the
engine shaft whereas the torque converter increases the torque in the ratio
of 2:1 or 3:1

19. Thank You