Patent Publication Number: US-2019186297-A1

Title: Fan drive gear system manifold radial tube filters

Description:
REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 14/414,550, filed on Jan. 13, 2015, which is a national phase application of International Application PCT/US2014/045346 filed on Jul. 3, 2014, which claims priority to U.S. Provisional Application No. 61/843,422 filed on Jul. 7, 2013. 
    
    
     BACKGROUND 
     A gas turbine engine typically includes a fan section, a compressor section, a combustor section and a turbine section. Air entering the compressor section is compressed and delivered into the combustion section where it is mixed with fuel and ignited to generate a high-speed exhaust gas flow. The high-speed exhaust gas flow expands through the turbine section to drive the compressor and the fan section. The compressor section typically includes low and high pressure compressors, and the turbine section includes low and high pressure turbines. 
     A speed reduction device such as an epicyclical gear assembly may be utilized to drive the fan section such that the fan section may rotate at a speed different than the turbine section so as to increase the overall propulsive efficiency of the engine. In such engine architectures, a lubricant routed through passages in a manifold to specific portions of the gear assembly. 
     The gear assembly may require lubricant in different temperatures and pressures to meet lubricant and cooling requirements. Moreover, the location of the geared architecture may provide a convenient means of directing lubricant to parts of the engine located near the gear assembly. Accordingly, the lubricant manifold includes separate passages for directing lubricant to different parts of the gear assembly and engine. A main filter is provided for the entire system and screens are placed within channels of the manifold to prevent contaminants from reaching portions of the gear assembly. The main filter is not suitable to control contaminants that may originate within the system that could interfere with gear operation. 
     Although geared architectures have improved propulsive efficiency, turbine engine manufacturers continue to seek further improvements to engine performance including improvements to thermal, transfer and propulsive efficiencies. 
     SUMMARY 
     A fan drive gear system according to an exemplary embodiment of this disclosure, among other possible things includes a geared architecture including gears supported by bearing structures for providing a speed change between an input and output, a lubricant manifold defining a first lubricant passage and a second lubricant passage, a first filtering characteristic for filtering lubricant flow to the first lubricant passage, and a second filtering characteristic for filtering lubricant flow to the second lubricant passage, wherein the second filtering characteristic is different than the first filtering characteristic. 
     In a further embodiment of the foregoing fan drive gear system, the first filtering characteristic includes a first filter element having a first porosity and the second filtering characteristic includes a second filter element having a second porosity different than the first porosity. 
     In a further embodiment of any of the foregoing fan drive gear systems, the first filter and the second filter include mesh screens. 
     In a further embodiment of any of the foregoing fan drive gear systems, mesh screens include metal mesh screens with a plurality of openings. 
     In a further embodiment of any of the foregoing fan drive gear systems, the first filter provides a first resistance to lubricant flow and the second filter provides a second resistance to lubricant flow that is less than the first resistance. 
     In a further embodiment of any of the foregoing fan drive gear systems, includes a first screen disposed within the first lubricant passage of the lubricant manifold downstream of the first filter and a second screen disposed within the second lubricant passage downstream of the second filter. 
     In a further embodiment of any of the foregoing fan drive gear systems, includes a first supply tube for supplying lubricant to the first lubricant passage and a second supply tube for supplying lubricant to the second lubricant passage. The first filter is disposed within the first supply tube and the second filter is disposed within the second supply tube. 
     In a further embodiment of any of the foregoing fan drive gear systems, at least one of the first and second filter elements is proximate a supply output end of the respective one of the first supply tube and the second supply tube. 
     In a further embodiment of any of the foregoing fan drive gear systems, the at least one of the first and second filter elements is removably positioned with the respective one of the first supply tube and the second supply tube. At least one of the first and second supply tubes is detachably connected to the geared architecture at the supply output and detaching the respective one of the first and second supply tube provides for removing and replacing the at least one of the first and second filter elements. 
     A lubrication system for gas turbine engine according to an exemplary embodiment of this disclosure, among other possible things includes a main lubricant passage including a main filter. A lubricant manifold is configured to receive lubricant from the main lubricant passage. The lubricant manifold defines a first lubricant passage and a second lubricant passage. A first filter element filters lubricant flow to the first lubricant passage. A second filter element filters lubricant flow to the second lubricant passage. The second filter is different than the first filter element. 
     In a further embodiment of the foregoing lubrication system, the first filter element is configured to provide lubricant flow at a first condition and the second filter element is configured to provide lubricant flow at a second condition different than the first condition. 
     In a further embodiment of any of the foregoing lubrication systems, the first condition includes a first temperature range and the second condition includes a second temperature range different than the first temperature range and the first filter is operable within the first temperature range and the second filter is operable within the second temperature range. 
     In a further embodiment of any of the foregoing lubrication systems, the first filter includes a first porosity and the second filter includes a second porosity different than the first porosity. 
     In a further embodiment of any of the foregoing lubrication systems, the first filter provides a first resistance to lubricant flow and the second filter provides a second resistance to lubricant flow that is less than the first resistance. 
     In a further embodiment of any of the foregoing lubrication systems, includes a first screen disposed within the first lubricant passage of the lubricant manifold downstream of the first filter and a second screen disposed within the second lubricant passage downstream of the second filter. 
     In a further embodiment of any of the foregoing lubrication systems, includes a first supply tube for supplying lubricant to the first lubricant passage and a second supply tube for supplying lubricant to the second lubricant passage. The first filter is disposed within the first supply tube and the second filter is disposed within the second supply tube. 
     A method of maintaining a fan drive gear system of a turbine engine according to an exemplary embodiment of this disclosure, among other possible things includes accessing a connection between a first supply tube and a lubricant manifold for supplying lubricant to a gear assembly of a fan drive gear system, removing a first filter mounted within the first supply tube, and visually checking the first filter for contaminants. 
     In a further embodiment of the foregoing method, includes accessing a connection between a second supply tube and the lubricant manifold, removing a second filter and visually checking the second filter for contaminants. 
     In a further embodiment of any of the foregoing methods, removing the first filter includes disconnecting the first supply tube from the lubricant manifold and removing the second filter comprises disconnecting the second supply tube from the lubricant manifold. 
     In a further embodiment of any of the foregoing methods, includes replacing the first filter with a filter including a flow characteristic different than a flow characteristic of the first filter. 
     Although the different examples have the specific components shown in the illustrations, embodiments of this disclosure are not limited to those particular combinations. It is possible to use some of the components or features from one of the examples in combination with features or components from another one of the examples. 
     These and other features disclosed herein can be best understood from the following specification and drawings, the following of which is a brief description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of an example gas turbine engine. 
         FIG. 2  is a schematic view of an example lubrication system for a gas turbine engine. 
         FIG. 3A  is a schematic view of an example first filter element. 
         FIG. 3B  is a schematic view of an example second filter element. 
         FIG. 3C  is a schematic view of an example third filter element. 
         FIG. 4  is a cross-sectional view of an example lubrication manifold supplying lubricant to various parts of a geared architecture. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  schematically illustrates an example gas turbine engine  20  that includes a fan section  22 , a compressor section  24 , a combustor section  26  and a turbine section  28 . Alternative engines might include an augmenter section (not shown) among other systems or features. The fan section  22  drives air along a bypass flow path B while the compressor section  24  draws air in along a core flow path C where air is compressed and communicated to a combustor section  26 . In the combustor section  26 , air is mixed with fuel and ignited to generate a high pressure exhaust gas stream that expands through the turbine section  28  where energy is extracted and utilized to drive the fan section  22  and the compressor section  24 . 
     Although the disclosed non-limiting embodiment depicts a turbofan gas turbine engine, it should be understood that the concepts described herein are not limited to use with turbofans as the teachings may be applied to other types of turbine engines; for example a turbine engine including a three-spool architecture in which three spools concentrically rotate about a common axis and where a low spool enables a low pressure turbine to drive a fan via a gearbox, an intermediate spool that enables an intermediate pressure turbine to drive a first compressor of the compressor section, and a high spool that enables a high pressure turbine to drive a high pressure compressor of the compressor section. 
     The example engine  20  generally includes a low speed spool  30  and a high speed spool  32  mounted for rotation about an engine central longitudinal axis A relative to an engine static structure  36  via several bearing systems  38 . It should be understood that various bearing systems  38  at various locations may alternatively or additionally be provided. 
     The low speed spool  30  generally includes an inner shaft  40  that connects a fan  42  and a low pressure (or first) compressor section  44  to a low pressure (or first) turbine section  46 . The inner shaft  40  drives the fan  42  through a speed change device, such as a geared architecture  48 , to drive the fan  42  at a lower speed than the low speed spool  30 . The high-speed spool  32  includes an outer shaft  50  that interconnects a high pressure (or second) compressor section  52  and a high pressure (or second) turbine section  54 . The inner shaft  40  and the outer shaft  50  are concentric and rotate via the bearing systems  38  about the engine central longitudinal axis A. 
     A combustor  56  is arranged between the high pressure compressor  52  and the high pressure turbine  54 . In one example, the high pressure turbine  54  includes at least two stages to provide a double stage high pressure turbine  54 . In another example, the high pressure turbine  54  includes only a single stage. As used herein, a “high pressure” compressor or turbine experiences a higher pressure than a corresponding “low pressure” compressor or turbine. 
     The example low pressure turbine  46  has a pressure ratio that is greater than about 5. The pressure ratio of the example low pressure turbine  46  is measured prior to an inlet of the low pressure turbine  46  as related to the pressure measured at the outlet of the low pressure turbine  46  prior to an exhaust nozzle. 
     A mid-turbine frame  58  of the engine static structure  36  is arranged generally between the high pressure turbine  54  and the low pressure turbine  46 . The mid-turbine frame  58  further supports bearing systems  38  in the turbine section  28  as well as setting airflow entering the low pressure turbine  46 . 
     Airflow through the core airflow path C is compressed by the low pressure compressor  44  then by the high pressure compressor  52  mixed with fuel and ignited in the combustor  56  to produce high speed exhaust gases that are then expanded through the high pressure turbine  54  and low pressure turbine  46 . The mid-turbine frame  58  includes vanes  60 , which are in the core airflow path and function as an inlet guide vane for the low pressure turbine  46 . Utilizing the vane  60  of the mid-turbine frame  58  as the inlet guide vane for low pressure turbine  46  decreases the length of the low pressure turbine  46  without increasing the axial length of the mid-turbine frame  58 . Reducing or eliminating the number of vanes in the low pressure turbine  46  shortens the axial length of the turbine section  28 . Thus, the compactness of the gas turbine engine  20  is increased and a higher power density may be achieved. 
     The disclosed gas turbine engine  20  in one example is a high-bypass geared aircraft engine. In a further example, the gas turbine engine  20  includes a bypass ratio greater than about six (6), with an example embodiment being greater than about ten (10). The example geared architecture  48  is an epicyclical gear train, such as a planetary gear system, star gear system or other known gear system, with a gear reduction ratio of greater than about 2.3. 
     In one disclosed embodiment, the gas turbine engine  20  includes a bypass ratio greater than about ten (10:1) and the fan diameter is significantly larger than an outer diameter of the low pressure compressor  44 . It should be understood, however, that the above parameters are only exemplary of one embodiment of a gas turbine engine including a geared architecture and that the present disclosure is applicable to other gas turbine engines. 
     A significant amount of thrust is provided by airflow through the bypass flow path B due to the high bypass ratio. The fan section  22  of the engine  20  is designed for a particular flight condition—typically cruise at about 0.8 Mach and about 35,000 feet. The flight condition of 0.8 Mach and 35,000 ft., with the engine at its best fuel consumption—also known as “bucket cruise Thrust Specific Fuel Consumption (‘TSFC’)”—is the industry standard parameter of pound-mass (lbm) of fuel per hour being burned divided by pound-force (lbf) of thrust the engine produces at that minimum point. 
     “Low fan pressure ratio” is the pressure ratio across the fan blade alone, without a Fan Exit Guide Vane (“FEGV”) system. The low fan pressure ratio as disclosed herein according to one non-limiting embodiment is less than about 1.50. In another non-limiting embodiment the low fan pressure ratio is less than about 1.45. 
     “Low corrected fan tip speed” is the actual fan tip speed in ft/sec divided by an industry standard temperature correction of [(Tram ° R.)/(518.7° R.)] 0.5 . The “Low corrected fan tip speed”, as disclosed herein according to one non-limiting embodiment, is less than about 1150 ft/second. 
     The example gas turbine engine includes the fan  42  that comprises in one non-limiting embodiment less than about twenty-six (26) fan blades. In another non-limiting embodiment, the fan section  22  includes less than about twenty (20) fan blades. Moreover, in one disclosed embodiment the low pressure turbine  46  includes no more than about six (6) turbine rotors schematically indicated at  34 . In another non-limiting example embodiment the low pressure turbine  46  includes about three (3) turbine rotors. A ratio between the number of fan blades  42  and the number of low pressure turbine rotors is between about 3.3 and about 8.6. The example low pressure turbine  46  provides the driving power to rotate the fan section  22  and therefore the relationship between the number of turbine rotors  34  in the low pressure turbine  46  and the number of blades  42  in the fan section  22  disclose an example gas turbine engine  20  with increased power transfer efficiency. 
     Referring to  FIG. 2  with continued reference to  FIG. 1 , the example turbine engine  20  includes a lubrication system  62  that provides lubricant flow at desired temperatures and pressures to various elements throughout the engine  20 . The lubrication system includes a pump  68 , a main supply  64  and a main filter  66 . A return circuit  112  returns lubricant to the supply  64 . Lubricant is pumped through a main lubricant circuit  70  to different passages that supply lubricant to various bearing assemblies  38  located throughout the engine  20  and to a lubricant manifold  72  mounted proximate the geared architecture  48 . 
     The lubricant manifold  72  provides lubricant to the geared architecture  48  and also to elements proximate to the lubricant manifold  72 . A first filter element  86  is disposed within a tube extending radially from the lubricant to the manifold  72 . The first filter  86  is in addition to the main filter  66  provided in the main lubricant circuit  70 . 
     The example lubricant system  62  supplies lubricant to the manifold  72 . The manifold  72  includes a first lubricant passage  74 , a second lubricant passage  76  and a third lubricant passage  78 . Each of the first, second and third lubricant passages  74 ,  76  and  78  are separate from the other such that the lubricant manifold  72  provides for different lubricant flows, temperatures, and other conditions of lubricant to be transmitted through the manifold  72  to various elements requiring lubrication and cooling. 
     The first passage  74  defined within the lubricant manifold  72  receives lubricant through a first lubricant circuit  80 . A second lubricant circuit  82  supplies the second passage  76  and a third lubricant circuit  84  supplies the third passage  78 . 
     The first lubricant circuit  80  includes a radially extending tube  81  that is connected to an inlet  92  of the manifold  72 . Disposed within tube  81  is the first filter element  86 . 
     The second circuit  82  includes a second radial tube  83  that is connected to a second inlet  94  and includes a second filter element  88 . The second filter element  88  is different than the first filter element  86 . 
     The third circuit  84  includes a third radial tube  85  that is connected to a third inlet  96  and includes a third filter element  90 . 
     The first passage  74  supplies lubricant to an outlet  100  that, in turn, supplies oil to journal bearings  126  ( FIG. 4 ) of the geared architecture  48 . As appreciated, although journal bearings are described by way of example in this disclosure other bearing arrangements such as for example roller, cylindrical and the like requiring lubricant are within the contemplation of this disclosure. 
     The second passage  76  provides lubricant to gears  120 , 122 ,  124  ( FIG. 4 ) within the geared architecture  48  along with a torque frame  130  ( FIG. 4 ) and other elements of the geared architecture  48  that require lubrication. 
     The third passage  78  provides a conduit through the lubricant manifold  72  to an outlet  102  to supply lubricant to other features that are proximate the geared architecture  48  and the lubricant manifold  72 . For example, other features that may receive lubricant directed through the lubricant manifold  72  can include bearing assemblies  38  proximate the geared architecture  48  to support rotation of the fan  42  or that are present in a forward portion to support rotation of the inner shaft  40 . Accordingly, the third passage  78  does not provide lubricant directly to the geared architecture  48 , but provides lubricant to other components that are proximate the geared architecture  48 . 
     It should be appreciated that each of the elements that are supplied lubricant through corresponding first, second and third passages  74 ,  76 , and  78  require lubricant to be supplied in different conditions. Such conditions include for example, different flow rates, temperatures, and pressures. Because each of the lubricant&#39;s circuits  80 ,  82  and  84  provide lubricant at different flows and temperatures, the filtering requirements at each of the connection points are different. Each of the first, second and third filters  86 , 88 , and  90  provide a different filtering or flow characteristic such as for example a desired resistance to flow and desired porosity to filter out contaminants of varying sizes, depending on the structure that is receiving that lubricant. For example, the journal bearings  126  may require a first porosity determined to provide lubricant at a first fluid flow rate to meet desired operational capacities. Moreover, the porosity may also be provided to prevent contaminants of a predetermined size. 
     The second filter element  88  supplying lubrication to the gears may require lubricant flow at a second rate that is different than the journal bearings  126 . Accordingly, the second filter element  88  will include a second porosity and size that is different than the first porosity and size of the first filter element  86 . 
     The third filter element  90  would also be of a different porosity and size to provide the desired lubricant flows from the outlet  102 . 
     Referring to  FIGS. 3A, 3B and 3C  with continued reference to  FIG. 2 , the example filter elements  86 ,  88 , and  90  are illustrated schematically. In this example, the first filter element  86  ( FIG. 3A ) includes a first porosity and is of a first size to provide a first resistance to flow. The second filter element  88  ( FIG. 3B ) is of a second porosity and a second size different than the first porosity and size. In this example, the second filter element  88  is larger than the first filter element  86  and includes a lower porosity and greater resistance to lubricant flow than the first filter element  86 . 
     The third filter element  90  includes larger openings and, thereby, a greater porosity than either of the first and second filter elements  86 ,  88 . Accordingly, the third filter element  90  is larger in size than the first and second filter elements  86 ,  88  and includes an increased porosity as compared to the first and second filter elements  86 ,  88 . 
     The filter elements  86 ,  88  and  90  are disposed within each of the radial tubes  81 ,  83  and  85  proximate corresponding inlets  92 ,  94  and  96  of the lubricant manifold  72 . Each of the radial tubes  81 ,  83  and  85  include a corresponding connection  114 ,  116  and  118  that attach to the corresponding inlets  92 ,  94  and  96  of the manifold  72 . 
     The first, second and third filter elements  86 ,  88  and  90  can be formed of metal mesh material including a desired number and size of openings to provide the desired porosity. Moreover, the first, second and third filter elements  86 ,  88  and  90  may be formed of porous synthetic material or any material that provides the desired porosity while being compatible with the pressures and temperatures encountered within the lubricant system  62 . 
     Referring to  FIG. 4  with continued reference to  FIG. 2  the example lubricant manifold  72  is shown in cross-sectioning with the first radial tube  81  shown inserted into the first inlet  92 . Lubricant flow  18 A communicated through the through the first circuit  80  passes through the first filter element  86  and into the first passage  74  of the lubricant manifold  72 . The first lubricant passage  74  communicates the first lubricant flow  18 A to the journal bearing  126 . The example journal bearing  126  includes an inner cavity in which is provided a screen  128  to capture contaminants that may be communicated through the lubricant manifold  72 . 
     In this example, the geared architecture  48  includes a sun gear  120  that drives planet gears  122  (only one shown here) that, in turn, drives a ring gear  124 . In this example, there are a plurality of planet gears  122  that are supported on corresponding one journal bearings  126 . The journal bearings  126  held within a carrier/torque frame assembly  130  to prevent rotation about the axis A. The journal bearing  126  is supplied with the first lubricant flow through the first lubricant passage  74  to provide lubrication to facilitate operation of the geared architecture  48 . 
     The second passage  76  through the manifold  72  supplies a second lubricant flow  18 B to the carrier/torque frame assembly  130  and also to other portions of the geared architecture, such as spray bars and other devices that communicate lubricant to elements within the geared architecture  48  other than the journal bearings  126 . 
     The third passage  78  communicates a third lubricant flow  18   c  out of the lubricant manifold  72  through outlet  105  to bearing assemblies and other structures that are proximate the geared architecture  48  and lubricant manifold  72 . 
     The use of the individual filter elements  86 ,  88  and  90  external to the lubricant manifold  72  within the radial tubes  81 ,  83  and  85  provides a secondary means of preventing contaminants from entering the geared architecture  48 . Moreover, because each of the first, second and third filter elements  86 ,  88  and  90  are disposed outside of the lubricant manifold  72 , maintenance and visual inspection is greatly simplified. As appreciated, each of the first, second and third filter elements  86 ,  88  and  90  can be accessed by disconnecting the corresponding radial tubes  81 ,  83  and  85  from the lubricant manifold  72  without disassembling the lubricant manifold or removing it from the geared architecture  48  or static support structure. 
     Accordingly, maintenance of the example geared architecture  48  can include inspection of the filter elements  86 ,  88  and  90  to determine if contaminants are present within the lubrication system  62 . Such maintenance includes accessing the connection point between the corresponding radial tubes  81 ,  83  and  85 . Disconnecting the radial tube, removing the corresponding filter elements  86 ,  88  and  90  and visually inspecting the filter element for contaminants that may have been captured within that element. 
     Maintenance may further include removal of one of the filter elements  86 ,  88 , and  90  and replacement with a filter element providing a different filtering characteristic, or flow characteristic. 
     Moreover, because each of the filter elements  86 ,  88  and  90  are different from each other, they provide a corresponding size and configuration to capture contaminants expected within each specific lubricant system. Moreover, the specific size and configuration of each of the filter elements  86 ,  88  and  90  are tailored to the requirements for oil supplied through that specific passage. In other words, contaminants with the journal bearing  126  may have a tolerance for contaminants of a specific size, whereas, the gears and carrier/torque frame assembly  130  can tolerate contaminants of another nature. Accordingly, each of the first, second and third filter elements  86 ,  88  and  90  are tailored to the tolerances of the specific features to which lubricant is supplied. 
     Moreover, the first, second and third lubricant flows  18 A,  18 B and  18 C may be of different pressures, temperatures and flow rates that in turn determine the specific nature, porosity, size and material of the corresponding filter. 
     Accordingly, the example lubricant manifold system provides for the tailoring of contaminant prevention and lubricant flow to each specific element by providing different filter elements of different configurations for communicating lubricant to each of the features. 
     Although an example embodiment has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this disclosure. For that reason, the following claims should be studied to determine the scope and content of this disclosure.