U.S. patent application number 10/491668 was filed with the patent office on 2005-02-17 for dry sump lubrication system with removable oil reservoir for wind turbine gearbox.
Invention is credited to Flamang, Peter, Smook, Warren.
Application Number | 20050034925 10/491668 |
Document ID | / |
Family ID | 9923316 |
Filed Date | 2005-02-17 |
United States Patent
Application |
20050034925 |
Kind Code |
A1 |
Flamang, Peter ; et
al. |
February 17, 2005 |
Dry sump lubrication system with removable oil reservoir for wind
turbine gearbox
Abstract
A gear unit for use in wind turbine applications has a dry sump
and is lubricated from an external reservoir whereby routine oil
change may be undertaken by removing an external reservoir
containing used oil and replacing it by a reservoir containing
fresh oil.
Inventors: |
Flamang, Peter; (Edegem,
BE) ; Smook, Warren; (Edegem, BE) |
Correspondence
Address: |
YOUNG & THOMPSON
745 SOUTH 23RD STREET
2ND FLOOR
ARLINGTON
VA
22202
US
|
Family ID: |
9923316 |
Appl. No.: |
10/491668 |
Filed: |
October 21, 2004 |
PCT Filed: |
October 4, 2002 |
PCT NO: |
PCT/IB02/04375 |
Current U.S.
Class: |
184/6.12 |
Current CPC
Class: |
Y02E 10/72 20130101;
F16H 1/46 20130101; F16H 57/0402 20130101; Y02E 10/722 20130101;
F16H 57/0434 20130101; F03D 15/00 20160501; F05B 2260/40311
20130101; F03D 15/10 20160501; F16H 57/0482 20130101; F03D 80/70
20160501 |
Class at
Publication: |
184/006.12 |
International
Class: |
F01M 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 5, 2001 |
GB |
01239730 |
Claims
1. Gear unit for use in wind turbine applications characterised by
the fact that the gear unit has a dry sump and is lubricated from
an external reservoir
2. Gear unit according to claim 1 characterised by the fact that
the gear unit consist of several modules each of which receives
fresh oil from the lubrication system and returns the used oil to
the external reservoir.
3. Gear unit according to claim 2 characterised by the fact that
each return line is equipped with a debris trap device allowing
evaluation of each of the modules.
4. Gear unit according to claim 1 characterised by the fact that
the regular oil change is carried out by removing the complete
external oil reservoir and replacing it with a fresh oil
reservoir
5. Gear unit according to claim 3 characterised by the fact that
not only the oil reservoir is exchanged at the time of oil change,
but also a number of dedicated parts of the oil conditioning system
attached to the reservoir.
6. Gear unit according to claim 2 characterised by the fact that
the gear unit comprises an integrated wind turbine rotor bearing
arrangement that is also lubricated with fresh oil from the same
reservoir.
7. Gear unit according to claim 5 characterised by the fact that
the gear unit is sealed at a large diameter by a sealing
arrangement whose function is based on non contacting sealing
principles.
Description
[0001] The present invention relates to a gear unit and
particularly but not exclusively to a gear unit for a wind
turbine.
[0002] Because of their position high up in the nacelle, a key
success factor of gear units for wind turbines is to provide low
weight and compactness. This has lead in the last decade to the
quasi general introduction of planetary low speed gear stages for
gear units in the power range beyond 500 kW and is now, in the
development of multi-MegaWatt turbines, leading to more and more
gear units with planetary low speed and intermediate gear
stages.
[0003] This evolution is leading to new challenges for the
designers of such turbines.
[0004] A basic characteristic of a planetary gear stage is that it
can contain only a very limited quantity of oil. A minimum quantity
of oil however is required in the lubrication system of the gear
unit to ensure that the oil does not degrade too fast and oil
change intervals are maximized.
[0005] At the same time, requiring large oil quantities complicates
oil changes on top of the nacelle due to cost and time involved in
the transport of oil barrels, draining and filling of the gear unit
By the nature of its construction, there are several disadvantages
to using the gear unit housing as the oil reservoir: the oil is
continuously churned around which leads to efficiency losses and
high cold-start torques, as well as possibly faster oxidation
because of a more intense contact of the oil with air, foam
building that can disturb lubrication systems and for instance oil
level alarms, etceteras.
[0006] Gear units typically contain several oil pockets that are
hard to flush when the oil is changed. Also, contamination of the
oil bath due to a failing component may easily lead to
consequential damage of other components as the particles from the
failing component are coming in the common oil sump of the gear
unit.
[0007] The present invention provides a novel solution for the
specific problems mentioned above.
[0008] The basic idea of the present invention is to completely
eliminate the oil sump in the gear unit. A seperate oil reservoir
is installed, from which well conditioned (cooled and filtered) oil
is fed to the gear unit. Although central lubrication systems exist
that provide oil for instance to different gear units in the same
plant or even to a single gear unit, these gear units mostly still
also need to enjoy the benefit of their own oil baths. Also the use
of external oil reservoirs, which in general would be regarded as
contrary to the objective of compactness, is not known in wind
turbine gear unit design.
[0009] Eliminating the oil bath in the gear unit as a whole however
can solve a number of the issues mentioned above. The uncoupling of
the gear unit lubrication circuit from the oil conditioning circuit
by means of an external oil reservoir moreover simplifies the
monitoring of the oil conditioning equipment itself, such as oil
heaters, cooling systems and filter systems.
[0010] As a further part of this invention, the gear unit is
constructed in such a way that the main gear stages are forming
seperate modules, each of which receives fresh conditioned oil from
the lubrication system and returns the used oil seperately to the
external oil reservoir. This has the advantage that contaminating
particles in one of the modules, for instance created by a failing
component or by external factors such as dirt or water
accumulation, are not allowed to contaminate the other modules, but
are intercepted by the separate oil conditioning system of the
reservoir.
[0011] Each of the return lines can be provided with a debris trap
device for instance by means of a transparent small reservoir
provided with a magnet and allowing visual inspection of the
presence of particles or debris.
[0012] Furthermore, the present invention also proposes to use an
oil reservoir that can be easily removed from the nacelle and
replaced by another fresh oil reservoir that contains well
conditioned oil. This exchange may include the most important parts
of the oil conditioning unit such as heaters, coolers and
filtration systems. The lubrication system thus receives a complete
"reset" at any oil change, removing all possibly accumulated dirt
or debris and also avoiding time consuming flushing of oil tanks
on-board of the nacelle. Against a background of a growing
off-shore market for wind turbines that are even more difficult to
service, this may be a large advantage.
[0013] A particulary interesting embodiment of the present
invention is shown in FIG. 1 which shows a schematic diagram of
cross-section of a gear unit and plural lubrication circuits A, B,
C and each serving a different module of the gear unit.
[0014] The shown gear unit consists of three modules comprising two
planetary gear stages 1 and 2 and a helical high speed gear stage
3. The wind turbine rotor bearing arrangement is integrated in the
gear unit. Fresh oil is fed from the external reservoir 4 by means
a pump 6 and via a flow distributor 7 to the three different
modules of the gear unit, and returned from these modules back to
the reservoir. The reservoir is provided with a separate oil
conditioning circuit 5.
[0015] For this particular construction, the invention with a dry
sump offers the additional advantage that the sealing arrangement
which has to be provided at a very large diameter, does not have to
seal of against any hydrostatic pressure that would be present in
case of an oil sump, and can therefore be based on non-contacting
sealing principles.
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