Gearbox assembly with lubricant extraction volume ratio

Abstract

A gearbox assembly includes a gearbox and a sump for collecting a gearbox lubricant purge flow from the gearbox. The sump is characterized by a lubricant extraction volume ratio between 0.01 and 0.3, inclusive. A gas turbine engine includes the gearbox assembly.

Description

Technical Field

[0001] This disclosure relates to a gearbox assembly for an engine. Background Technology

[0002] Lubricant is used in power gearboxes to lubricate the gears and rotating components within the gearbox. Lubricant can be provided to lubricate the meshing between gears. As the gears of the gearbox assembly rotate during operation, the lubricant is expelled. The lubricant is also trapped in grooves. Attached Figure Description

[0003] The features and advantages of this disclosure will become apparent from the following more specific description of various exemplary embodiments, as illustrated in the accompanying drawings, wherein similar reference numerals generally denote the same, functionally similar, and / or structurally similar elements.

[0004] Figure 1 A schematic cross-sectional view of an engine taken along its centerline axis according to an embodiment of the present disclosure is shown.

[0005] Figure 2 An embodiment according to this disclosure is shown. Figure 1 A schematic detailed view of the gearbox assembly of the engine.

[0006] Figure 3 The following is illustrated according to an embodiment of the present disclosure. Figure 1 The line 3-3 was cut Figure 2 A schematic end view of the gearbox assembly, with the fan shaft omitted for clarity.

[0007] Figure 4 A graph showing the lubricant extraction volume ratio as a function of gearbox power according to an embodiment of the present disclosure is shown.

[0008] Figure 5 A graph showing the lubricant extraction volume ratio as a function of gearbox power according to an embodiment of the present disclosure is shown. Detailed Implementation

[0009] The features, advantages, and embodiments of this disclosure will be set forth or apparent from consideration of the following detailed description, drawings, and claims. Furthermore, it should be understood that the following detailed description is exemplary and intended to provide further explanation, and does not limit the scope of the claimed disclosure.

[0010] Various embodiments are discussed in detail below. Although specific embodiments are discussed, this is for illustrative purposes only. Those skilled in the art will recognize that other components and configurations can be used without departing from the spirit and scope of this disclosure.

[0011] As used herein, the terms “first,” “second,” and “third” are used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of the individual components.

[0012] The terms "front" and "rear" refer to relative positions within a gas turbine engine or vehicle, and specifically to the normal operating posture of the gas turbine engine or vehicle. For example, in the case of a gas turbine engine, "front" refers to the position closer to the engine inlet, while "rear" refers to the position closer to the engine nozzle or exhaust port.

[0013] The terms "upstream" and "downstream" refer to the relative directions of fluid flow within a fluid path. For example, "upstream" refers to the direction from which the fluid flows out, and "downstream" refers to the direction from which the fluid flows in.

[0014] The terms “connection,” “fixation,” “attachment to,” “link,” etc., refer to both direct connection, fixation, attachment, or linking, and indirect connection, fixation, attachment, or linking through one or more intermediate components or features, unless otherwise stated herein.

[0015] Unless the context clearly indicates otherwise, the singular forms “a,” “one,” and “the” include plural references.

[0016] As used herein, the terms "axial" and "axially" refer to a direction and orientation that extends substantially parallel to the centerline of the turbine engine. Furthermore, the terms "radial" and "radially" refer to a direction and orientation that extends substantially perpendicular to the centerline of the turbine engine. Additionally, as used herein, the terms "circumferential" and "circumferentially" refer to a direction and orientation that extends arcuately around the centerline of the turbine engine.

[0017] Throughout this specification and claims, scope limitations are combined and interchanged, and unless the context or language otherwise indicates otherwise, such scopes are identified and include all subscopes contained herein. For example, all scopes disclosed herein include endpoints, and endpoints may be combined independently of each other.

[0018] A turbine engine can be configured as a geared engine. A geared engine includes a power gearbox for transmitting power from the turbine shaft to a fan. This gearbox may include a sun gear, multiple planetary gears, and a ring gear. The sun gear meshes with the multiple planetary gears, and the multiple planetary gears mesh with the ring gear. In operation, the gearbox transmits torque from the turbine shaft, which operates at a first speed, to the fan shaft, which rotates at a lower second speed. In a planetary configuration of the gearbox, the sun gear may be coupled to the intermediate shaft of the low-pressure turbine, which rotates at the first speed. The planetary gears mesh with the sun gear and then transmit torque to the fan shaft via planet carriers. In a radial configuration, the ring gear is coupled to the fan shaft.

[0019] In any configuration, maximizing efficiency is desirable. Several factors can negatively impact gearbox efficiency. For example, gearboxes experience wind resistance in rotating components (e.g., in bearings, rolling surfaces, and gears), meaning shear forces and drag are generated in the gears, pins, and bearings of the gearbox. In another example, the rotating components of the gearbox experience frictional losses due to the relative rotation between components. Wind resistance and frictional losses reduce gearbox efficiency. In addition to reduced efficiency, wind resistance and frictional losses also cause the gearbox to generate heat. The relative rotating surfaces between gears and the transmission of forces also generate heat within the gearbox.

[0020] When the gearbox operates at higher efficiency, a larger percentage of the input power from the LP shaft is transferred to the fan shaft. To improve gearbox efficiency, lubricant is supplied to the gearbox to provide a protective film on the rolling contact surfaces to lubricate the components and remove heat from the gearbox. However, the lubricant supplied to the gearbox needs to be removed from it. Lubricant buildup in the gearbox can reduce efficiency and may prevent heat removal. Furthermore, allowing lubricant from the gearbox to enter other parts of the engine can negatively impact the operation of those components. One method of removing lubricant from the gearbox is through grooves. Grooves collect the lubricant discharged from the gearbox during operation. Grooves are often designed to confine the gear ring without considering the requirements of the engine or gearbox. This can result in grooves that are too large or too small. Grooves larger than required by the engine occupy valuable space in the engine, increase engine weight, and reduce overall engine efficiency. Grooves smaller than required by the engine may not properly remove lubricant from the gearbox, leading to leakage from the grooves and reducing the lubricant's ability to remove heat from the gearbox. The inventors sought to improve existing groove methods to accommodate the size / capacity requirements of specific architectures, gearbox types, and / or mission requirements, and to test different groove configurations to determine which factors would affect the appropriate groove size.

[0021] Figure 1 A schematic cross-sectional view of engine 10 is shown. Engine 10 can be, for example, but not limited to, a turbine engine, such as a gas turbine engine. Engine 10 defines an axial direction A extending parallel to the longitudinal engine centerline 12, a radial direction R perpendicular to the axial direction A, and a circumferential direction C around the engine centerline 12. Figure 1 (Displayed within / outside the page). Engine 10 includes fan section 14 and core engine 16 downstream of fan section 14.

[0022] The core engine 16 includes a core engine housing 18, which is substantially tubular and defines an annular inlet 20. The core engine housing 18 surrounds, in a series flow relationship: a compressor section 22 including a low-pressure compressor 24, also referred to as a turbocharger 24, downstream of which is a high-pressure compressor 26; a combustion section 28; a turbine section 30 including a high-pressure turbine 32, downstream of which is a low-pressure turbine 34; and an exhaust nozzle section 72 downstream of the low-pressure turbine 34. A high-pressure shaft 36 drives the high-pressure turbine 32 to the high-pressure compressor 26, causing the high-pressure turbine 32 and the high-pressure compressor 26 to rotate synchronously. The compressor section 22, combustion section 28, and turbine section 30 together define a core airflow path 38 extending from the annular inlet 20 to the exhaust nozzle section 72.

[0023] The low-pressure shaft 40 drives the low-pressure turbine 34 to the supercharger 24, causing the low-pressure turbine 34 and the supercharger 24 to rotate in unison. The gearbox assembly 100 connects the low-pressure shaft 40 to the fan shaft 42 to drive the fan blades 44 of the fan section 14. The fan shaft 42 is connected to the fan frame 74 via bearings 76. The fan blades 44 extend radially outward from the engine centerline 12 in direction R. The fan blades 44 rotate about the engine centerline 12 via the fan shaft 42, which is powered by the low-pressure shaft 40 passing through the gearbox assembly 100. The gearbox assembly 100 regulates the rotational speed of the fan shaft 42, and thus regulates the rotational speed of the fan blades 44 relative to the low-pressure shaft 40. In other words, the gearbox assembly 100 is both a reduction gearbox and a power gearbox, transmitting torque from the low-pressure shaft 40, which operates at a first speed, to the fan shaft 42, which operates at a slower second speed and is connected to the fan blades 44.

[0024] exist Figure 1 In this configuration, fan section 14 includes an annular fan casing or nacelle 46 circumferentially surrounding at least a portion of fan blades 44 and / or core engine 16. Nacelle 46 is supported relative to core engine 16 by a plurality of circumferentially spaced outlet guide vanes 48. Furthermore, a rear portion 50 of nacelle 46 extends circumferentially around a portion of the outer casing of core engine 16 to define a bypass airflow passage 52 therebetween.

[0025] During operation of engine 10, a volume of air, represented by airflow 54, enters engine 10 through inlet 56 of nacelle 46 and / or fan section 14. As airflow 54 passes through fan blades 44, a first portion of airflow 54, represented by bypass airflow 58, is directed or directed into bypass airflow passage 52, and a second portion of airflow 54, represented by core airflow 60, is directed or directed into the upstream section of core airflow path 38 via annular inlet 20. The ratio between bypass airflow 58 and core airflow 60 defines the bypass ratio. As core airflow 60 is directed through high-pressure compressor 26 and into combustion section 28, the pressure of core airflow 60 increases, wherein the now high-pressure core airflow 60 mixes with fuel and combusts to provide combustion products or combustion gases, represented by flow 62.

[0026] Combustion gases are guided via flow 62 to high-pressure turbine 32 and expanded therethrough. A portion of the thermal and / or kinetic energy from the combustion gases is extracted via a sequential stage of high-pressure turbine stator blades connected to the core engine housing 18 and high-pressure turbine rotor blades 64 connected to the high-pressure shaft 36, thereby causing the high-pressure shaft 36 to rotate and thus supporting the operation of the high-pressure compressor 26. The combustion gases then enter low-pressure turbine 34 via flow 62 and expand therethrough. Here, a second portion of the thermal and kinetic energy is extracted from the combustion gases via a sequential stage of low-pressure turbine stator blades connected to the core engine housing 18 and low-pressure turbine rotor blades 66 connected to the low-pressure shaft 40, thereby causing the low-pressure shaft 40 to rotate. This, in turn, supports the operation of the supercharger 24 and the rotation of the fan blades 44 via the gearbox assembly 100.

[0027] Combustion gases are then guided via flow 62 through the injection exhaust nozzle section 72 downstream of the low-pressure turbine 34 to provide propulsive thrust. The high-pressure turbine 32, the low-pressure turbine 34, and the injection exhaust nozzle section 72 at least partially define the hot gas path 70 for guiding combustion gases through the core engine 16 via flow 62. Simultaneously, the pressure of the bypass flow 58 increases as it is guided through the bypass flow passage 52 before exiting the fan nozzle exhaust section 68 of the engine 10, also providing propulsive thrust.

[0028] Figure 1The engine 10 depicted is merely an example. In other exemplary embodiments, the engine 10 may have any other suitable configuration. For example, in other exemplary embodiments, the fan section 14 may be configured in any other suitable manner (e.g., as a fixed-pitch fan) and may also be supported using any other suitable fan frame configuration. Furthermore, it should be understood that in other exemplary embodiments, any other suitable number or configuration of compressors, turbines, shafts, or combinations thereof may be provided. In yet another exemplary embodiment, aspects of this disclosure may be incorporated into any other suitable turbine engine, such as a turbofan engine, propeller engine, turbojet engine, and / or turboshaft engine.

[0029] Figure 2 The gearbox assembly 100 is shown. Figure 1 Detailed video Figure 5 . Figure 3 The gear of gearbox assembly 100 is shown along the edge. Figure 1 A schematic axial end view taken from line 3-3. For clarity, Figure 3 The fan shaft 42 and connector 43 are omitted. (See reference...) Figure 2 and Figure 3 The gearbox assembly 100 includes a gearbox 101 and a groove 114. The gearbox 101 includes a sun gear 102, a plurality of planetary gears 104, and a ring gear 106. Low-pressure turbine 34 ( Figure 1 The low-pressure shaft 40 drives the sun gear 102, which is connected to the gearbox assembly 100. The gearbox assembly 100 then drives the fan shaft 42.

[0030] refer to Figure 2 The low-pressure shaft 40 causes the sun gear 102 to rotate about the engine centerline 12. Radially outside and meshing with the sun gear 102 are a plurality of planet gears 104 connected together by a planet carrier 108. The planet carrier 108 is connected to the engine frame 112 via a flexible mount 110. The planet carrier 108 constrains the plurality of planet gears 104 while allowing each of the plurality of planet gears 104 to rotate about its respective planet gear axis 105 on a pin 107. Figure 3 Radially outside and meshing with the plurality of planetary gears 104 is a ring gear 106, which is an annular ring gear 106. The ring gear 106 is connected to the fan shaft 42 at the coupling 43. The ring gear 106 is connected to the fan blades 44 via the fan shaft 42. Figure 1 This drives the fan blades 44 to rotate about the engine centerline 12. The groove 114 includes a groove wall 116 having an inner surface 118 and an outer surface 120. The groove volume V G It is confined within the interior 122 of the trench wall 116. The trench volume V G For the purpose of explanation Figure 2 The dashed line in the figure shows, although it is understandable, volume V G It extends all the way to the inner surface 118 of the groove 114. Although the groove 114 is depicted as having a relatively bell-shaped or teardrop shape, it is understood that the groove 114 can be depicted in any suitable shape to collect lubricant.

[0031] Although Figure 2 Not depicted in the text; for clarity, only partially shown. Figure 3 In this gearbox, each of the sun gear 102, the plurality of planetary gears 104, and the ring gear 106 includes teeth surrounding their periphery for meshing with the teeth of adjacent gears. The gearbox 101 has a gearbox diameter D defined by the outer diameter of the gearbox 101. GB The outer diameter of gearbox 101 can be the outer diameter of gear ring 106, such that the gearbox diameter D... GB Defined by the outer diameter of gear ring 106. (Reference) Figure 2 The sun gear 102, multiple planetary gears 104, and ring gear 106 are axially aligned such that the front ends 124 and rear ends 126 of the gears are coplanar. The gearbox 101 has an axial gearbox length L defined from the front ends 124 to the rear ends 126 of the gears. GB .

[0032] refer to Figure 3 The groove 114 may be circular and may be wholly or partially external to the gears of the gearbox assembly 100. For example, the groove 114 may be wholly or partially external to the ring gear 106. Therefore, the groove 114 is located radially outside the sun gear 102, the plurality of planetary gears 104, and the ring gear 106. The groove 114 does not rotate with the gears of the gearbox assembly 100.

[0033] The groove 114 includes a clearing port 115 located at or near the bottom of the groove 114. The clearing port 115 allows the removal of lubricant collected in the groove 114 from the gearbox assembly 100. Although shown as a large opening in the groove 114, the clearing port 115 can be any size or shape of hole or port that allows fluid to flow from the interior 122 of the groove 114 to the exterior of the gearbox assembly 100. By positioning the clearing port 115 at or near the bottom of the groove 114, gravity can help direct lubricant flow toward the clearing port 115, thus facilitating the removal of lubricant from the gearbox assembly 100. Once removed from the groove 114, the lubricant can pass through the lubricant passage 128 (…). Figure 2 Recycled and / or collected elsewhere for disposal and / or removal.

[0034] Figure 2 and Figure 3The gearbox assembly 100 is a star-configured gearbox assembly, wherein the planet carrier 108 is held fixed (e.g., fixed to the engine frame 112 via a flexible mount 110) and the ring gear 106 is allowed to rotate. That is, the fan section 14 is driven by the ring gear 106. However, other suitable types of gearbox assemblies 100 may be used. In a non-limiting example, the gearbox assembly 100 may be a planetary configuration, wherein the planet carrier 108 is coupled to the fan shaft 42 via an output shaft ( Figure 1 This allows the fan shaft 42 to rotate while the gear ring 106 remains stationary or fixed. In this example, fan segment 14 ( Figure 1 The gearbox assembly 100 is driven by the planet carrier 108. In another non-limiting example, the gearbox assembly 100 may be a differential gearbox, in which both the ring gear 106 and the planet carrier 108 are allowed to rotate.

[0035] During engine operation, refer to Figure 2 and Figure 3 The gears of gearbox assembly 100 rotate as previously described. Lubricant is provided to lubricate the rotating parts of gearbox assembly 100, including the sun gear 102, a plurality of planetary gears 104, a ring gear 106, and pins 107. A lubricant system (not shown for clarity) supplies a flow F1 (also referred to as the first lubricant flow F1) of lubricant through lubricant channel 128 to supply lubricant to gearbox assembly 100. As the gears of gearbox assembly 100 rotate, centrifugal force displaces the lubricant radially outward away from the engine centerline 12, as shown by flow F2, also referred to as the second lubricant flow F2, or gearbox purging flow F2. Flow F2 flows around the ring gear 106 and / or through the ring gear channel 130 to be collected by groove 114. Lubricant flows into groove inlet 113. In this way, the lubricant supplied through lubricant channel 128 is collected in groove 114 after flowing through and around the gears and other rotating parts of gearbox assembly 100.

[0036] As the volume of gearbox 101 increases, the diameter D of the gearbox also increases. GB As the power output of gearbox 101 increases, the heat generated also increases. This increased heat generation increases the amount of lubricant required to operate the gearbox, necessitating an increase in the groove volume V for clearing lubricant trapped by the system and recirculating it. G However, there is also a desire to reduce the overall coverage of the gearbox, oil, and scavenging systems, with a focus on reducing the packaging space available for the gearbox and oil scavenging systems, particularly for engines with power gearboxes that operate at relatively high gear ratios (e.g., between 2.5-3.5, 3.0, 3.25, 4.0 and above, including the endpoints).

[0037] Given the above, it is desirable to improve or at least maintain the target efficiency of the gearbox without making the size of the groove or cleaning system excessive, or simultaneously reduce its size to accommodate the required or adaptable increase in weight or volume. When developing a gas turbine engine, the interactions between components can make selecting or developing a component (e.g., groove 114) particularly difficult during engine design and prototyping, especially when some components are at different stages of completion. For example, one or more components may be nearing completion, while one or more other components may be in the initial or preliminary stages. It is desirable to achieve the possible results early in the design process, thus making it more possible to select the optimal candidate design from the options, with trade-offs in mind. To date, this process has sometimes been more ad hoc, selecting one design or another without knowing the effects when the concept was first considered. For example, various aspects of the design of fan section 14, compressor section 22, combustion section 28, and / or turbine section 30 may not be known when designing the groove, but these components affect the required size of gearbox 101 and the amount of lubricant required, and thus influence the design of groove 114.

[0038] The inventors sought a more favorable balance between maximizing gearbox clearance flow collection and minimizing other potential negative impacts on previously addressed incorrect choices of groove size, such as conducting multivariate trade studies that may or may not have yielded improved or best-matched groove / clearance for a particular architecture. Unexpectedly, a relationship was found between groove volume and gearbox volume that uniquely identifies a limited and easily determined number of embodiments (in light of this disclosure) suitable for a particular architecture, improving the weight-volume-clearance effectiveness tradeoff for that architecture. The inventors refer to this relationship as Lubricant Extraction Volume Ratio (LEVR):

[0039]

[0040] V G Represents the trench volume, such as according to Figure 2 and Figure 3 Yes, it is definite. The trench volume can be determined by calculating the volume within the trench's cross-section. V GB The gearbox volume is defined as follows (2). For engine power between 18kHP and 35kHP (inclusive), the gearbox volume V is... GB In 800in 3 (cubic inches) and 2000in 3 Between, including the endpoints. In some examples, the engine is a turbofan engine. The inventors discovered that the trench volume V G The selection range should be 0.01≤LEVR≤0.3 (the groove volume is between 1% and 30% of the gearbox volume, including the endpoints).

[0041]

[0042] L GB Represents the length of the gearbox, as shown in the figure. Figure 2 Certainly. Although in Figure 2 The description refers to gears of the same length. In cases where the gears have different lengths, the gearbox length can be defined by any one of the sun gear 102, planet gear 104, or ring gear 106. In (2), D GB Represents the diameter of the gearbox, as shown in the figure. Figure 3 It's confirmed.

[0043] In some embodiments, and as Figure 4 As shown in region 400, the LEVR is between 0.01 and 0.3, including the endpoint, and the maximum power of the gearbox is between 35 kHP and 90 kHP, including the endpoint. In some embodiments, and as... Figure 5 As shown in region 500, for a maximum gearbox power less than or equal to 35 kHP, LEVR is between 0.03 and 0.3, including the endpoints.

[0044] If the groove volume relative to the gearbox volume exceeds the LEVR limit (e.g., "large groove"), the volume within the groove is too large, exceeding the volume required for gearbox lubricant removal. This can lead to increased lubricant turbulence losses and lubricant foaming within the groove, resulting in increased power losses across the entire gearbox assembly. Foaming in the groove creates resistance and negatively impacts gearbox performance, ultimately affecting engine performance. Furthermore, large grooves require more radial space, and the added material, mass, and size of large grooves encroach on other system components within the engine (e.g., core flow paths), again negatively impacting gearbox performance. LEVR is chosen to balance gearbox lubricant removal recovery with its impact on engine operation and efficiency.

[0045] If the groove volume relative to the gearbox volume violates the lower LEVR limit (e.g., "small groove"), the volume within the groove required for gearbox lubricant removal is too small. The groove will not completely capture the gearbox lubricant removal (e.g., flow F2), resulting in insufficient removal of lubricant from the gearbox oil sump. This can cause lubricant leakage back into the gearbox and / or other areas of the engine, negatively impacting gearbox and engine performance. The lower LEVR limit is chosen to balance gearbox lubricant removal recovery with its impact on gearbox and engine operation and efficiency (e.g., volume and weight losses).

[0046] Considering the above factors in selecting the upper and lower limits, LEVR can also be defined based on power factor, flow transition time, and heat density parameters:

[0047]

[0048] Where PF represents the power factor, FT represents the flow transition time, and HDP represents the heat density parameter. The power factor PF is defined in (4) as:

[0049] PF=PD*(1-η) (4)

[0050] Where PD represents gearbox power density and η represents gearbox efficiency. Power density PD is the ratio of gearbox power to gearbox volume, and is defined as 15000 hp / ft. 3 and 45000hp / ft 3 Between, including the endpoints. Gearbox efficiency is between 99.2% and 99.8%, including the endpoints.

[0051] The flow transition time FT is given by the following formula:

[0052]

[0053] Where V G Represents trench volume, such as regarding Figure 2 and Figure 3 As determined. V dot This represents the volumetric flow rate of the lubricant. The lubricant volumetric flow rate is limited by the gearbox power and efficiency. Because the low efficiency of the gearbox generates heat, a certain amount of lubricant is needed to dissipate this heat. The flow transition time is the time required for the lubricant to traverse the entire groove volume. The flow transition time indirectly relates the groove volume to the gearbox volume. The flow transition time ranges from 1.5 to 11 seconds, including the endpoints.

[0054] The thermal density parameter HDP is defined as follows:

[0055] HDP=ρ*C*ΔT (6)

[0056] Where ρ represents fluid density, C represents specific heat of lubricant, and ΔT represents temperature rise in lubricant, between 20 degrees Celsius and 45 degrees Celsius, including the endpoints.

[0057] Table 1 describes exemplary embodiments 1 and 2 for identifying LEVRs for various engines. Embodiments 1 and 2 are for narrow-body turbofan engines. However, the LEVRs of this disclosure are not limited to such engines and can be applied to a wide range of thrust levels and engine designs, including, for example, wide-body engines. In some examples, the engine may include, but is not limited to, commercial jet propulsion engines, small turbofan engines, open rotor engines, marine and industrial turbine engines, including portable power generation units, and marine propulsion for ships.

[0058]

[0059] Table 1

[0060] As gearbox power and therefore gearbox size / volume increase, the groove volume must also increase to ensure proper groove function. However, the relationship between LEVR and gearbox (fan) power is not linear. Furthermore, different gearbox configurations (such as planetary and differential gearboxes) may require higher lubricant flow rates due to lower efficiency compared to planetary gearbox configurations. Therefore, these higher-power gearboxes with different operating configurations can produce LEVRs close to 0.3. Table 1 illustrates this relationship for planetary gearbox configurations.

[0061] Therefore, the groove volume is crucial for minimizing lubricant removal losses as the lubricant leaves the gearbox and is redirected to the groove's removal port.

[0062] Therefore, this disclosure defines a lubricant extraction volume ratio for improving or maintaining gearbox efficiency, while ensuring that the grooves in which the gearbox is located are not too large or too small relative to the gearbox requirements. By keeping the grooves within the range defined by the lubricant extraction volume ratio, the negative effects of grooves that could lead to reduced gearbox efficiency (e.g., increased system weight and size) are minimized, thereby maximizing scavenging and collection.

[0063] Further aspects of this disclosure are provided through the subject matter of the following clauses.

[0064] According to an aspect of this disclosure, a gearbox assembly includes a gearbox and a groove. The groove is used to collect a gearbox lubricant scavenging flow from the gearbox, and the groove is characterized in that the lubricant extraction volume ratio is between 0.01 and 0.3, and includes endpoints.

[0065] According to the gearbox assembly of the foregoing clause, wherein for gearbox power less than or equal to 35 kHP, the lubricant extraction volume ratio is between 0.03 and 0.3, including the endpoints.

[0066] The gearbox assembly according to any of the preceding clauses, wherein the lubricant extraction volume ratio is defined by the ratio of the groove volume to the gearbox volume.

[0067] The gearbox assembly according to any of the preceding clauses, wherein the groove volume is defined by the inner surface of the groove wall of the groove.

[0068] The gearbox assembly according to any of the preceding clauses, wherein the gearbox volume is defined by the outer diameter of the gearbox and the gearbox length of the gearbox.

[0069] The gearbox assembly according to any of the preceding clauses, wherein the outer diameter of the gearbox is the outer diameter of the gear ring.

[0070] The gearbox assembly according to any of the preceding clauses, wherein the length of the gearbox is defined between the foremost front end and the rearmost rear end of the gear in the gearbox.

[0071] The gearbox assembly according to any of the preceding clauses, wherein the gearbox includes a sun gear, a plurality of planetary gears and a ring gear.

[0072] The gearbox assembly according to any of the preceding clauses, wherein the lubricant extraction volume ratio is defined by the ratio of the groove volume to the gearbox volume.

[0073] The gearbox assembly according to any of the preceding clauses, wherein the gearbox volume is defined by the outer diameter of the gear ring and the length of the gearbox.

[0074] The gearbox assembly according to any of the preceding clauses, wherein the lubricant extraction volume ratio is defined by power factor, flow transition time, and thermal density parameters.

[0075] The gearbox assembly according to any of the preceding clauses, wherein the flow transition time is defined by the groove volume of the groove and the lubricant volumetric flow rate through the gearbox.

[0076] The gearbox assembly according to any of the preceding clauses, wherein the flow transition time is between 1.5 seconds and 11 seconds, including the endpoints.

[0077] The gearbox assembly according to any of the preceding clauses, wherein the power factor is defined by the power density of the gearbox and the efficiency of the gearbox.

[0078] The gearbox assembly according to any of the foregoing clauses, wherein the power density is 15000 hp / ft 3 and 45000hp / ft 3 Between, including the endpoints, and the efficiency is between 99.2% and 99.8%, including the endpoints.

[0079] According to an aspect of this disclosure, a gas turbine engine includes a gearbox assembly comprising a gearbox and a groove. The groove is used to collect a gearbox lubricant scavenging flow from the gearbox, and is characterized in that the lubricant extraction volume ratio is between 0.01 and 0.3, and includes an end point.

[0080] According to any of the preceding clauses, in a gas turbine engine, when the gas turbine engine has an engine power of 35 kHP or greater, the lubricant extraction volume ratio is between 0.01 and 0.3, including the endpoints.

[0081] The gas turbine engine according to any of the preceding clauses, wherein the engine power is between 35 kHP and 90 kHP, including the endpoints.

[0082] The gas turbine engine according to any of the preceding clauses, wherein the lubricant extraction volume ratio is between 0.03 and 0.3, including the endpoints.

[0083] According to any of the preceding clauses, in a gas turbine engine, when the gas turbine engine has an engine power of less than or equal to 35 kHP, the lubricant extraction volume ratio is between 0.03 and 0.3, including the endpoints.

[0084] According to any of the preceding clauses, in a gas turbine engine, the lubricant extraction volume ratio is defined by the ratio of the groove volume to the gearbox volume.

[0085] In a gas turbine engine according to any of the preceding clauses, the volume of the groove is defined by the inner surface of the groove wall.

[0086] The gas turbine engine according to any of the preceding clauses, wherein the gearbox volume is defined by the outer diameter of the gearbox and the gearbox length of the gearbox.

[0087] In a gas turbine engine according to any of the preceding clauses, the outer diameter of the gearbox is the outer diameter of the gear ring.

[0088] In a gas turbine engine according to any of the preceding clauses, the length of the gearbox is limited between the foremost and rearmost ends of the gears in the gearbox.

[0089] The gas turbine engine according to any of the preceding clauses, wherein the gearbox includes a sun gear, a plurality of planetary gears and a ring gear.

[0090] According to any of the preceding clauses, in a gas turbine engine, the lubricant extraction volume ratio is defined by the ratio of the groove volume to the gearbox volume.

[0091] In a gas turbine engine according to any of the preceding clauses, the gearbox volume is defined by the outer diameter of the gear ring and the length of the gearbox.

[0092] The gas turbine engine according to any of the preceding clauses, wherein the lubricant extraction volume ratio is defined by power factor, flow transition time, and thermal density parameters.

[0093] The gas turbine engine according to any of the preceding clauses, wherein the power factor is defined by the power density of the gearbox and the efficiency of the gearbox.

[0094] The gas turbine engine according to any of the foregoing clauses, wherein the power density is 15000 hp / ft 3 and 45000hp / ft 3 Between, including the endpoints, and the efficiency is between 99.2% and 99.8%, including the endpoints.

[0095] The gas turbine engine according to any of the preceding clauses, wherein the flow transition time is defined by the groove volume of the groove and the lubricant volumetric flow rate of the lubricant through the gearbox.

[0096] The gas turbine engine according to any of the preceding clauses, wherein the flow transition time is between 1.5 seconds and 11 seconds, including the endpoints.

[0097] The gas turbine engine according to any of the preceding clauses, wherein the gearbox includes a sun gear, a plurality of planetary gears and a ring gear, and wherein the groove is external to the ring gear.

[0098] In a gas turbine engine according to any of the preceding clauses, the groove is completely external to the gear ring.

[0099] In a gas turbine engine according to any of the preceding clauses, the groove is partially external to the gear ring.

[0100] The gas turbine engine according to any of the preceding clauses, wherein the groove is located radially outside the gearbox.

[0101] The gas turbine engine according to any of the preceding clauses, wherein the trench further includes a clearing port located near the bottom of the trench.

[0102] The gas turbine engine according to any of the foregoing clauses, wherein the gearbox is in a radial configuration.

[0103] The gas turbine engine according to any of the foregoing clauses, wherein the gearbox is a planetary configuration.

[0104] The gas turbine engine according to any of the foregoing clauses, wherein the gearbox is a differential gearbox.

[0105] According to any of the preceding clauses, the gas turbine engine, wherein when the engine power is between 18 kHP and 35 kHP (inclusive), the gearbox volume is 800 in. 3 and 2000in 3 Between, including the endpoints.

[0106] The gas turbine engine according to any of the preceding clauses, wherein the groove volume is between 0.01 and 0.3 times the gearbox volume, including the endpoints.

[0107] The gearbox assembly according to any of the preceding clauses, wherein the gearbox includes a sun gear, a plurality of planetary gears and a ring gear, and wherein the groove is external to the ring gear.

[0108] The gearbox assembly according to any of the foregoing clauses, wherein the groove is completely external to the gear ring.

[0109] The gearbox assembly according to any of the preceding clauses, wherein the groove is partially external to the gear ring.

[0110] The gearbox assembly according to any of the preceding clauses, wherein the groove is located on the radially outer side of the gearbox.

[0111] The gearbox assembly according to any of the preceding clauses, wherein the groove further includes a clearing port located near the bottom of the groove.

[0112] The gearbox assembly according to any of the foregoing clauses, wherein the gearbox is in a star configuration.

[0113] The gearbox assembly according to any of the foregoing clauses, wherein the gearbox is in a planetary configuration.

[0114] The gearbox assembly according to any of the preceding clauses, wherein the gearbox is a differential gearbox.

[0115] According to any of the preceding clauses, the gearbox assembly wherein, when the engine power is between 18 kHP and 35 kHP (inclusive), the gearbox volume is 800 in. 3 and 2000in 3 Between, including the endpoints.

[0116] The gearbox assembly according to any of the preceding clauses, wherein the groove volume is between 0.01 and 0.3 times the gearbox volume, including the endpoints.

[0117] While the foregoing description is directed to preferred embodiments, other variations and modifications will be apparent to those skilled in the art and can be made without departing from the spirit or scope of this disclosure. Furthermore, features described in connection with one embodiment may be used in conjunction with other embodiments, even if not explicitly stated above.

Claims

1. A gearbox assembly, characterized in that, include: Gearbox; and A groove for collecting gearbox lubricant scavenging flow from the gearbox, characterized in that, for a maximum gearbox power greater than 35 kHP and less than or equal to 90 kHP, the lubricant extraction volume ratio is between 0.01 and 0.3, including the endpoints; or for a maximum gearbox power less than or equal to 35 kHP, the lubricant extraction volume ratio is between 0.03 and 0.3, including the endpoints, the lubricant extraction volume ratio being defined as: ,in It is the trench volume. That is the volume of the gearbox.

2. The gearbox assembly according to claim 1, characterized in that, in, The volume of the trench is defined by the inner surface of the trench wall.

3. The gearbox assembly according to claim 1, characterized in that, in, The volume of the gearbox is defined by the outer diameter of the gearbox and the length of the gearbox.

4. The gearbox assembly according to claim 3, characterized in that, in, The outer diameter of the gearbox is the outer diameter of the gear ring.

5. The gearbox assembly according to claim 3, characterized in that, in, The length of the gearbox is limited between the frontmost end and the rearmost end of the gears in the gearbox.

6. The gearbox assembly according to claim 1, characterized in that, in, The gearbox includes a sun gear, multiple planetary gears, and a ring gear.

7. The gearbox assembly according to claim 6, characterized in that, in, The volume of the gearbox is defined by the outer diameter of the gear ring and the length of the gearbox.

8. The gearbox assembly according to claim 1, characterized in that, in, The lubricant extraction volume ratio is limited by power factor, flow transition time, and thermal density parameters.

9. The gearbox assembly according to claim 8, characterized in that, in, The flow transition time is defined by the groove volume of the groove and the lubricant volumetric flow rate through the gearbox.

10. The gearbox assembly according to claim 8, characterized in that, in, The flow transition time is between 1.5 seconds and 11 seconds, including the endpoints.

11. The gearbox assembly according to claim 8, characterized in that, in, The power factor is defined by the power density of the gearbox and the efficiency of the gearbox.

12. The gearbox assembly according to claim 11, characterized in that, in, The power density is 15000 hp / ft 3 and 45000 hp / ft 3 Between, including the endpoints, and the efficiency is between 99.2% and 99.8%, including the endpoints.

13. A gas turbine engine, characterized in that, include: Gearbox assembly, the gearbox assembly comprising: Gearbox; and A groove for collecting gearbox lubricant scavenging flow from the gearbox, characterized in that, for a maximum gearbox power greater than 35 kHP and less than or equal to 90 kHP, the lubricant extraction volume ratio is between 0.01 and 0.3, including the endpoints; or for a maximum gearbox power less than or equal to 35 kHP, the lubricant extraction volume ratio is between 0.03 and 0.3, including the endpoints, the lubricant extraction volume ratio being defined as: ,in It is the trench volume. That is the volume of the gearbox.

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