FIELD OF THE INVENTION
The present invention relates to an Eddy current clutch to increase cooling rate
of engine cooling water in Broad gauge diesel electric locomotives.
BACKGROUND OF THE INVENTION
Eddy current clutch (ECC) is used for driving a radiator fan which cools the
engine cooling water in diesel electric locomotives.
The Eddy current clutch operates on outer rotor speed (input from Engine), and
mechanical power unit from diesel locomotive engine. The machine takes
mechanical power from the engine to rotate the radiator fan. The radiator fan
moves at pre-determined speed and cools the engine cooling water.
Radiator fan of ECC moves with a speed in the range 1000-1320 rpm. Radiator
fan cools the engine cooling water and engine cooling water cools the engine.
For this range of speed, cooling rate of the engine is not sufficient. So, it
becomes necessary to increase the cooling rate. For increasing the cooling rate,
the radiator fan has to move at a much faster speed. The ECC having a gear
ratio of 1.3870 (instead of 1.3125 in existing design) increases the speed of the
radiator fan and hence provides increased cooling to the engine.
OBJECT OF THE INVENTION
It is therefore an object of the invention to propose an eddy current clutch to
increase cooling rate of water available for cooling of an engine of diesel electric
locomotive.
SUMMARY OF THE INVENTION
According to the invention, the ECC is configured with a higher gear ratio
(number of teeth in the gear divided by number of teeth in the pinion) to
enhance the speed of the radiator fan. Due to increase in the speed of the
radiator fan, cooling rate of water used in the engine of diesel locomotive
engines is increased.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 - shows an eddy current clutch according to the invention.
Figure 2 - shows a sectional view of the bevel gear arrangement of the
Eddy current clutch of Figure 1.
DETAIL DESCRIPTION OF THE INVENTION
As shown in figure-1, an eddy current clutch (ECC) consists of an outer rotor (1),
an inner rotor (2), a slip ring (3), gear box (4), a spiral bevel gear (5), a radiator
fan (6), a vertical shaft (7), and a horizontal shaft (8). The horizontal shaft is
connected to the engine with the help of a coupling. When the engine is started,
the mechanical power is transmitted from the engine to the horizontal shaft (8).
The horizontal shaft (8) moves axially and it transmits power from horizontal to
vertical direction. As a result, the radiator fan starts moving. An inner face of the
outer rotor (1) is coated with copper liners. When the inner rotor (2) is rotated
inside the outer rotor (1), maintaining a small air gap, an eddy current is
generated. This eddy current allows the outer rotor (1) to rotate. The vertical
shaft (7) is supported by a pair of roller bearing (11) disposed in bearing housing
(9).
A Spiral bevel gear (5) arrangement is used to transmit the motion between the
intersecting shafts (7,8) with the usual angle of 90°C between them (Figure 2).
These gears impose radial and thrust loads on tapered roller bearings (10). The
ECC is rigidly fixed on a mounting plate (13).
A direct current in a field coil produces a magnetic field that determines the
torque transmitted from the engine rotor (input rotor) to the output rotor (8).
The ECC provides a closed loop speed regulation by varying clutch current, and
allowing the clutch to transmit enough torque to operate at the desired speed.
In the inventive ECC, the gear ratio is increased to 1.3870 to increase cooling
rate of the engine of the diesel electric locomotive. Engine cooling rate can be
increased by increasing the cooling rate of the radiator cooling water. This can
be achieved by increasing the speed of the radiator, cooling fan (6). Radiator fan
speed is controlled by regulating the engine speed through the gear box (4) of
the spiral bevel gear arrangement (5). In order to increase the radiator fan
speed, the gear ratio has been increased form 1.3125 to 1.3870 based on engine
cooling calculation. The ECC is enabled to maintain a speed range between 1000
-1386 rpm.
WE CLAIM
1. An eddy current clutch to enhance cooling of engine cooling water in
diesel electric locomotives, comprising:
- an inner rotor disposed into an outer rotor, the inner rotor rotating
inside the outer rotor maintaining a small gap in-between;
- an engine providing mechanical power to a horizontal shaft for axial
movement, the horizontal shaft having two end-bearings disposed
in respective housing;
- the outer rotor rotating when an eddy current generated through
rotation of the inner shaft maintaining said gap;
- a spiral bevel gear arrangement transmitting motion between the
inner and the outer shaft intersecting at a 90° angle;
- a vertical shaft movable vertically corresponding to the axial
movement of said horizontal shaft, the vertical shaft provided with
a pair of tapered bearing on both sides;
- a radiator fan operating to cool the engine cooling water, the
rotation of the radiator fan is interdependent with the vertical
movement of the vertical shaft; and
- a slip ring enabled to provide a closed loop speed regulation by
varying the clutch current, application of a direct current in the field
coils of the inner rotor producing a magnetic field that determines
the torque rate from the engine to be transmitted to the output
rotor.
2. An eddy current clutch to enhance cooling of engine cooling water in
diesel electric locomotives

The present invention relates to an eddy current clutch to enhance cooling of
engine cooling water in diesel electric locomotives, comprising an inner rotor
disposed into an outer rotor, the inner rotor rotating inside the outer rotor
maintaining a small gap in-between; an engine providing mechanical power to a
horizontal shaft for axial movement, the horizontal shaft having two end-
bearings disposed in respective housing; the outer rotor rotating when an eddy
current generated through rotation of the inner shaft maintaining said gap; a
spiral bevel gear arrangement transmitting motion between the inner and the
outer shaft intersecting at a 90° angle; a vertical shaft movable vertically
corresponding to the axial movement of said horizontal shaft, the vertical shaft
provided with a pair of tapered bearing on both sides; a radiator fan operating to
cool the engine cooling water, the rotation of the radiator fan is interdependent
with the vertical movement of the vertical shaft; and a slip ring enabled to
provide a closed loop speed regulation by varying the clutch current, application
of a direct current in the field coils of the inner rotor producing a magnetic field
that determines the torque rate from the engine to be transmitted to the output
rotor.