1) The document discusses fluid couplings and torque converters used to transmit power between shafts without a rigid connection. 2) A fluid coupling uses an impeller and turbine runner enclosed in a casing filled with fluid. Torque is transmitted from the impeller to the turbine via centrifugal force on the fluid. 3) A torque converter is similar but can vary the output torque through a reaction vanes between the impeller and turbine. This allows torque and speed transformation between input and output shafts.

1. GUIDED BY : RESPECTED DHORAJ KAMAL JAMUWA SIR
SUBMITTED BY : DEEPAK KUMAR SOLANKI
BRANCH : MECHANICAL ENGG.
CLASS : B.TECH. 2ND YEAR, 4TH SEM.

2. FLUID COUPLING :
FUNCTION :
To transmit power from one shaft to
another, magnitudes of input and output torques are
equal.
Construction and Working :
It is consists of two shafts driving and
driven shaft which are enclosed in a single housing
without any rigid or mechanically connection
between them; contact is only through a working
fluid contained in the casing.

3. The working oil serves to transmit torque from the
pump impeller to the turbine runner. When air
From the pump impeller exerts torque sufficient
enough to overcome the inertia of turbine blades, it
also begins to run.
Operation :
When the pump impeller starts
rotating, the oil in the coupling thrown outward by
centrifugal action. The oil then enters in the turbine
and exerts a force on the runner. Magnitude of the
increases with an increase in the speed of the

4. driving shaft and eventually when this torque
overcomes in the inertia effects, the turbine runner
and the driven shaft begin to rotate. The oil thus
gains energy from the impeller and delivers it to the
runner. Further the oil circulates in the closed path;
overflow of pump comprises the inflow to turbine
and discharge from the turbine is fed back at the
suction of the pump.

5. power output
Efficiency of fluid coupling = -------------------
power input
To * Wo
η = ---------
(fc) Ti * Wi
Wi - Wo Wo
Slip S = ---------- = 1 - ----
Wi Wi

7. TORQUE CONVERTER :
Function :
To transmit increased or decreased
power from one shaft to another. A variable torque
is impressed on the driven Member without the
use of gear train or clutch.

8. Construction and Working :
A torque converter comprises :
1. Pump impeller coupled to the driving shaft ,
2. Turbine runner coupled to the driven shaft , and
3. Reaction member or fixed guide vane arranged
between the pump impeller and the turbine
runner.

10. Liquid flowing from pump impeller to turbine runner
exerts a torque on the stationary vanes. These vanes
change the direction of liquid ,Thereby making possible
a torque and speed transformation. The torque
relationship is prescribed by :
To = Ti + Tv
Where Tv is the torque of guide vanes. Then
power input = Wi * Ti
power output = Wo * To = Wo (Ti + To)

11. Efficiency of torque converter ,
Wo (Ti + Tv)
η = ------------------
Wi * Ti