DESCRIPTION OF THE DRAWINGS
Reference is now made to the accompanying figures depicting aspects of the present invention, in which:
FIG. 1 is a schematic cross-sectional view of a gas turbine engine;
FIG. 2 is an enlarged schematic cross-sectional view of the fan and compressor section of the gas turbine engine, illustrating the emplacement of the No. 1 bearing, No. 2 bearing, the No. 3 bearing, the upper towershaft (UTS) gear mesh and the UTS bearing of the gas turbine engine shown in FIG. 1,
FIG. 3 is a perspective view of an oil distributing unit for providing individual jets for the No. 1, No. 2 & No. 3 bearings, the UTS gear mesh and the UTS bearing shown in FIG. 2;
FIG. 4 is a cross-sectional view showing an outlet transfer port of the oil distribution unit attached to a first transfer tube for directing oil forward to No. 1 bearing of the gas turbine engine shown in FIG. 1;
FIG. 5 is a cross-sectional view showing another outlet transfer port of the oil distribution unit attached to a second transfer tube for directing oil rearward to the No. 3 bearing damper of the gas turbine engine shown in FIG. 1;
FIG. 6 is a cross-sectional view of a portion of the oil distributing unit of FIG. 2, showing a nozzle thereof in spaced relation with the No. 2 bearing of the gas turbine engine shown in FIG. 1; and
FIG. 7 is a cross-sectional view of a portion of the oil distributing unit of FIG. 2, showing anther nozzle thereof in spaced relation with an upper towershaft bearing of the gas turbine engine of FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates a gas turbine engine 10 of a type preferably provided for use in subsonic flight, generally comprising in serial flow communication a fan 12 through which ambient air is propelled, a multistage compressor 14 for pressurizing the air, a combustor 16 in which the compressed air is mixed with fuel and ignited for generating an annular stream of hot combustion gases, and a turbine section 18 for extracting energy from the combustion gases.
Generally, the gas turbine engine 10 comprises a low pressure shaft 20 and a high pressure shaft 22 concentrically mounted about an engine centerline 24 as shown in FIGS. 1 and 2. The low pressure (LP) shaft 20 connects a low pressure turbine (LPT) 18b to fan 12, and the high pressure (HP) shaft 22 connects a high pressure turbine (HPT) 18a to the high pressure compressor (HPC) 14. Both high and low pressure rotor assemblies include multiple components. A tower shaft 105 is in meshing engagement with the high pressure shaft 22 to drive an accessory gearbox (AGB) 108, as well known in the art.
FIG. 2 shows three bearings 39, 40 and 42 respectively commonly referred to as the No. 1, No. 2 and No. 3 bearings of the engine 10. In the illustrated example, the No. 2 and No. 3 bearings (bearings 40 and 42) are located in a same bearing compartment 44. The No. 1 bearing (bearing 39) is located in a separate compartment. However, it is understood that all three bearings 39, 40 and 42 could be located in a common bearing compartment. The No. 1 and No. 2 bearings (bearing 39 and 40) provide support to the LP shaft 20, whereas the No. 3 bearing (bearing 42) provides support to the HP shaft 22.
The bearing compartment 44 houses other components, such as upper tower shaft bearing 106 and the upper tower shaft gear mesh 120, that also need to be lubricated. The space available in the bearing compartment 44 to house all these components and bearings is very limited.
As shown in FIGS. 2 and 3, an oil distributing unit 50 is mounted in the bearing compartment 44 in accordance with a particular embodiment of the present invention. The oil distributing unit 50 comprises a central body 52 having a single inlet port 54 in fluid communication with multiple outlet ports 56a, 56b, 56c . . . . The oil distributing unit 50 is configured for fitting into the bearing compartment 44 having a three dimensional shape accommodating the tight clearances between the various static and rotating components.
More particularly, the central body 52 has an elongated cylindrical shape defining a central conduit 58 along a line of sight 59 as shown in FIG. 3. The central conduit 58 is in fluid communication with the inlet port 54. A first transfer port 60 extends from a first end 62 of the central body 52 in fluid communication with central conduit 58. The first transfer port 60 is adapted to direct a flow of oil forward to a first additional oil system including the No. 1 bearing 39 and associated damper 64 (FIGS. 2 and 4). Particularly, the first transfer port 60 includes a bore 66 for receiving a first transfer tube 68 attached therein as shown in FIGS. 3 and 4.
Similarly, a second transfer port 70 extends from a second end 72 of the central body 52 in fluid communication with central conduit 58. The second transfer port 70 is adapted to direct a flow of oil rearward to a second additional oil system shown as the No. 3 bearing damper 74 in FIG. 5. Particularly, the second transfer port 70 includes a bore 76 for receiving a second transfer tube 78 attached therein as shown in FIGS. 3 and 5.
Still referring to FIG. 3, the oil distributing unit 50 further comprises first, second and third cylindrical members 80, 82 and 84 respectively extending from the central body 52 in different three-dimensional directions determined by the location of the components in the bearing compartment 44 which require lubrication. The first member 80 defines conduit 86 extending along a line of sight 88 and in fluid communication with the central conduit 58. The first member 80 branches off into first and second nozzles 90 and 92 adapted for spraying the No. 2 bearing 40, as shown in FIG. 6, and the No. 3 bearing 44 respectively. Each nozzle 90 and 92 defines a spray orifice 94 and 96 respectively that communicates with conduit 86 of the first member 80.
The second member 82 similarly defines conduit 98 extending along a line of sight 100 and in fluid communication with the central conduit 58. The second member 82 branches off into first and second nozzles 102 and 104 adapted for spraying the upper towershaft (UTS) bearing 106, as shown in FIG. 7, and the No. 3 bearing 44 respectively. Each nozzle 102 and 104 defines a spray orifice 110 and 112 respectively that communicates with conduit 98 of the second member 82.
The third member 84 similarly defines conduit 114 extending along a line of sight 116 and in fluid communication with the central conduit 58. The third member 84 branches off into nozzle 118 adapted for spraying the upper towershaft (UTS) gearmesh 120. Nozzle 118 defines a spray orifice 122 that communicates with conduit 114 of the third member 84.
It should be understood that the nozzles 90, 92, 102, 104 and 118 of the oil distributing unit 50 are spaced from the respective components in the bearing compartment 44 a predetermined clearance for optimizing the use of space in the compartment 44 and for ensuring proper lubrication.
Still referring to FIG. 3, the oil distributing unit 50 further comprises an attachment feature 124 for mating engagement with a corresponding feature 126 at attachment site 128 adjacent a main oil supply feed line 128. The attachment feature 124 connects the inlet port 54 to the main oil supply feed line 128. More specifically, the attachment feature 124 is exemplified as a bolt 130, tab washer 132, pin (not shown) and packing (not shown).
In operation, the main oil supply feed line 128 of the engine 10 supplies a continuous flow of oil to the oil distributing unit 50 through inlet port 54. The flow of oil travels through the central conduit 58 defined in the central body 52 and subsequently branches out to first, second and third conduits 86, 98 and 114 to spray the components requiring lubrication. The flow of oil is also directed forward and rearward through first and second transfer ports to additional oil systems as described above. Notably, the flow rate is controlled by the diameter of the ports, conduits and orifices. The oil flow rate is preferably maintained below 10 ft/s so as to avoid cavitations.
The oil distributing unit 50 presented above advantageously combines nozzles that were previously individual components and transfer ports for directing oil to additional oil systems. Such a combination of outlets into one unit that is fed by a single inlet reduces overall part count as a single attachment feature is required.
Furthermore, the oil distributing unit 50 above-described is manufactured in accordance with a particular method of the present invention. The oil distributing unit 50 is cast as a single piece having a predetermined geometry that enables the unit 50 to be assembled in the bearing compartment 44 of the engine 10. Notably the oil distributing unit 50 is cast in a light weight aluminium material. The conduits 58, 86, 98 and 114 are preferable drilled along the respective line of sites 60, 88, 100 and 116 and then plugged to ensure that the oil flow is distributed to the nozzles. Similarly, the inlet 54 and bores 66 and 76 of transfer ports 60 and 70 are straight drilled to tap off of the central conduit 58
The method of manufacturing presented above is advantageous because the use of cores during casting to cast core passages is avoided as the latter tend to shift, trap dirt or are difficult to clean. In the case of ceramic cores that generally do not move, a time consuming etching process for removal thereof is required. In the above method, simple straight drilling is done to machine the conduits, thus time is saved in manufacturing the oil distributing unit.
The above description is meant to be exemplary only, and one skilled in the art will recognize that changes may be made to the embodiments described without department from the scope of the invention disclosed. For example, the oil distributing unit may be configured to direct oil to any number of additional oil systems and may comprises any number of nozzles for lubricating components in the bearing compartment in which the unit is provided. Still other modifications which fall within the scope of the present invention will be apparent to those skilled in the art, in light of a review of this disclosure, and such modifications are intended to fall within the appended claims.
Patent Application
20080083227
