If you want to know about Volvo Penta Engine Power Take-off, this article will be helpful.
P.T.O. Positions
Accessories such as compressors
and steering servo pumps etc. can be driven from different power take-off
locations on the engine. These locations vary depending on engine type, but
generally the accessories can be:
a installed on the engine and be
belt driven from a power take-off groove on the crankshaft belt pulley. If the
accessory is installed a long way from the engine, engine movement must be
taken into consideration e.g by using a spring-loaded guide roller. b installed
on the timing cover front or rear, gearwheel driven from the camshaft drive.
WARNING!
When engines are delivered
without protection all rotating parts must be protected if it, after being
built into the respective application, is necessary for personal safety.
Belt Driven P.T.O.
Crankshaft belt pulley, front end
The amount of power available at
the crankshaft belt pulley depends on power take-off belt pulley distance from
the cylinder block surface and the direction of the vector forces that affect
the belt pulley. It is also dependent on belt pulley diameter and engine rpm.
Crankshaft belt pulleys are available for every engine type. Some have an
integral power take-off groove, while others can be fitted with a bolt-on power
take-off disc.
Tightening torques
If the crankshaft belt pulley is
changed, the new pulley must be tightened to the correct torque. Tightening
torques are stated in the service manual for each engine type.
More detailed information is
available in the Sales Support Tool, Partner Network.
Belt Tension
All belt-driven power take-off
connections must have the correct belt tension, as insufficient belt tension
may cause the belts to slip at high loads and high rpm, which will shorten belt
life etc. If the power take-off is driven by the crankshaft, overtight belt
tension will cause higher side loads than necessary, which may cause damage to
the crankshaft bearing. Belt tension can be tested by applying pressure to the
middle on the greatest belt distance between two belt pulleys and adjusting the
tension until the belt only yields to a given measurement; refer to the
illustration. On installations with several belts where there are two or more
belts between two belt pulleys, the belts must have the same length in order
for the load to be distributed evenly and for the belts to last as long as
possible.
Idler Pulleys
Idler wheels used to tension
V-belts must be located on the slack side of the belt and may not be narrower
than the minimum diameter recommended by the belt manufacturer.
Belt pulleys that are too small
will shorten belt life considerably. A spring-loaded belt pulley is preferable
to one that is adjusted and fixed, as a spring-loaded pulley ensures belt
tension is maintained. This becomes more important the greater power take-off
values are, as tauter belt tension is required to avoid belt slippage, and this
causes greater side loads/bending moment on the crankshaft and its bearings.
NOTICE! It is also important to
use a spring-loaded idler pulley where internal movement may occur between a
flexibly mounted engine and driven equipment installed on a separate chassis.
Gear driven P.T.O.from Timing
Case
Limitation
Check that the engine
specifications are suitable for the installation of power take-off equipment.
- Weight: Consideration must be
given to how much the equipment to be bolted to the timing covers weighs. A
support bracket on the cylinder block must be used for heavy equipment.
- Cyclical torque: Certain
equipment, e.g. hydraulic pumps, cause large cyclical torque variations on the
timing gears. This means that the maximum torque according to the data in the
Sales Support Tool, Partner Network, may not be used. All power take-off
equipment for connection directly to the timing cover must be approved by Volvo
Penta.
PTO (Repto)
The illustration shows where the
PTO is located on TAD1370 engines.
The connection point is standard
and fits:
1 SAE-B, max load 600 Nm
2 DIN-5462, max load 650 Nm
3 DIN-5462, max load 1000 Nm
NOTICE! DIN-5462 and max load of
1000 Nm may only be ordered when purchasing new engines.
Air Compressors
Air compressors can be driven in
the following ways:
1 From the timing gear.
2 By belt drive.
Make sure that the compressor is
of a recommended type before it is installed. Otherwise information must be
sent to Volvo Penta for approval and to ascertain whether momentary torque
loads are within the engine gear wheel transfer capacity and that the
compressor is not too heavy.
Things to remember concerning
Power Take-off at the Timing
Gears
- The factor that determines
drive lifetime is torque.
- If a torque higher than that
specified is used, drive lifetime will be shortened.
- If the same power (P) is used
at a lower engine rpm, torque will be higher and drive lifetime will therefore
be shortened according to the formula:
V-Belt Transmissions
V-belt transmissions can easily
be adapted to different gear ratios (by using different drive pulley sizes).
This type of transmission provides flexible power transfer with a low noise
level and requires relatively little maintenance. However, alignment must be
accurate and belt tension must be easy to adjust.
Crankshaft Side Loadings,
Flywheel End
The permissible crankshaft
side-load magnitude depends on the type of engine, operating rpm, and engine
application. Original equipment manufacturers may contact Sales
Engineering Industrial, AB Volvo
Penta, Sweden for detailed information on maximum permissible crankshaft side
loads, and for advice regarding specific installation problems.
Direction of the Side Loadings
The engine will normally manage a
greater side load (F) below the shaft than above it, in which case the belt
drive must wherever possible be arranged such that the driven equipment is
located below the crankshaft centerline. If two or more belt drives are
required and it is possible to install them in opposite directions, their
effects will cancel each other out and minimize total side load on the
crankshaft bearings.
Unsupported P.T.O. Pulley
If it is necessary to use a power
take-off belt pulley without support, the design must be inspected and approved
by Volvo Penta.
The following information must be
provided:
1 Engine specifications:
2 A drawing of the drive
arrangements including the following:
a Average diameter of all belt
pulleys in the system.
b Power take-off belt distances
from the cylinder
block front or rear surface.
c Number, size and type of belts
to be used.
d The location of the driven
equipment in relation to the engine.
e Belt tensioning method, e.g.
adjustable fixed pulley, spring-loaded pulley etc.
f The equipment's maximum and
continuous power requirements.
P.T.O. Support Bearings
On installations where it is
necessary to transfer large forces or where several belts are required, the
power take-off shafts must be supported by bracket bearings or reinforced
support bearings. Large side loads occur in V-belt transmissions. We therefore
emphasize the importance of accurate alignment. Furthermore, V-belt tension
must be checked carefully.
This is especially important if
multi-grooved belt pulleys are to be used. If the V-belts are unevenly
tensioned in relation to each other, it will lead to increased loads on the
bearings and a displacement of the load center. Preferably, use a multi-groove
V-belt; see illustration.
WARNING!
When engines are delivered
without protection all rotating parts must be protected if it, after being
built into the respective application, is necessary for personal safety.
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