Patent Application
20210246898
The application relates generally to pumps and, more particularly, to multi-stage pumps for aircraft engines.
Aircraft engines, such as gas turbine engines or jet engines, typically include one or more pumps. Such pumps can be used for pumping oil to operate machinery implements, supplying oil to turbine engine systems, for pumping an air/oil mixture from an oil sump from a jet engine or from an airframe or engine mounted gearboxes, for instance. Various engines configurations may provide limited space for such pumps, and/or the sizes or dimensions for some pump configurations, like multi-stage pumps, may limit engine design possibilities.
In one aspect, there is provided a pump assembly having at least two pump stages operatively engaged to each other via a transmission. In one variant of the pump assembly, the transmission may be coupled to respective shafts of the at least two pump stages to transmit torque from one pump stage to the other.
In another aspect, there is provided a pump assembly comprising: at least one casing having a first pump chamber defining a first flow path and at least a second pump chamber defining a second flow path; a first pump stage including a first shaft mounted to the casing for rotation about a rotation axis, a first pair of intermeshing gears disposed in the first flow path of the first pump chamber, the first pair of intermeshing gears interfacing each other in operative engagement, one intermeshing gear of the first pump stage mounted on the first shaft; at least a second pump stage including a second shaft mounted to the casing for rotation about a rotation axis different than the rotation axis of the first shaft, a second pair of intermeshing gears disposed in the second flow path of the at least second pump chamber, the second pair of intermeshing gears interfacing each other in operative engagement, one intermeshing gear of the second pump stage mounted on the second shaft; and a transmission drivingly engaging the first shaft to the second shaft.
In a further aspect, there is provided a pump assembly for an aircraft engine, comprising a casing enclosing at least a first and a second pump stages, the at least first and second pump stages including respective pairs of intermeshing rotating components disposed in respective pump chambers of the casing, the pairs of rotating components mounted for rotation relative to the casing via at least one shaft of the first pump stage and at least one shaft of the second pump stage, a transmission drivingly engaging the pairs of rotating components of the first and second pump stages by coupling to the at least one shaft of the first pump stage and the at least one shaft of the second pump stage.
In a further aspect, there is provided a gear pump assembly comprising: a housing defining a first pump chamber and at least a second pump chamber, the first and second pump chambers forming respective first and second fluid paths; a first pump stage including a first pair of intermeshing gears in fluid-structure interaction with the first fluid path and mounted into the first pump chamber for rotation about respective rotation axes via a first shaft and a second shaft mounted to the housing; at least a second pump stage including a second pair of intermeshing gears in fluid-structure interaction with the second fluid path and mounted into the second pump chamber for rotation about respective rotation axes via a third and a fourth shafts mounted to the housing, the rotation axes of the first and the second pair of intermeshing gears radially spaced apart with respect to each other; a transmission drivingly engaging one of the first and second shafts to one of the third and fourth shafts, and a power input gear mounted on one of the first, second, third and fourth shafts, the power input gear operatively engageable to a power source to transmit torque to the first pump stage and at least the second pump stage.
Reference is now made to the accompanying figures in which:
Aircraft engines, including the type of engine shown in
Referring to
In
As shown, the power input gear 12 transmits workload from the power source to the pump stages P1 to P5. The pump stages P1 to P5 of the pump assembly 10 are all driven by workload transmitted by the power input gear 12 via the common shaft 11A, which has one of the rotating elements 14 of each pump stage P1 to P5 mounted thereto. Torque may be transferred from that rotating element 14 mounted on shaft 11A to the other rotating element 14 mounted on shaft 11B. In this case, the power input gear 12 is the only power input of the pump assembly 10 that provides power to the pump stages P1 to P5. A fuse F (e.g. mechanical or electrical fuse or switch) is located at the power input of the pump assembly 10. In case of emergency or other situations requiring sudden stop of the pump assembly 10, the fuse F may break, disengage or otherwise cut off the power supplied to the pump assembly 10. The pump assembly 10 configured with a fuse F (or other types of safety system) may be desirable in situations where, for instance, scavenge pump(s) (or scavenge pump stages of the pump assembly 10) fail(s) thus requiring the shutdown of pressure pump(s) to avoid or limit adverse effects of the absence or lack of lubricating fluid or lubricating fluid overflow in engine components fluidly supplied by the pump assembly 10.
An axial pump architecture, such as the example of pump assembly 10 shown in
A pump assembly 20 is described herein with reference to various embodiments. The pump assembly 20 defines two or more pump stages operatively engaged to each other via a transmission. In an embodiment, the transmission is drivingly engaged to respective shafts (e.g. by direct coupling or indirect coupling via an intermediary piece or component) of distinct pump stages to transmit torque from one pump stage to the other.
Referring to
The pump assembly 20 comprises a transmission 23 operatively engaging two (or more) of the pump stages 30, 40, 50. Depending on the embodiment, the transmission 23 may be configured to cause different rotational speeds in one pump stage 30 relative to another pump stage 40 drivingly engaged via the transmission 23. This may be done by having different gear ratios or transmission ratios within the transmission 23. This may allow tuning of the speed of the pump stages based on operating parameters of the engine 1 and/or engine 1 requirements, and/or allow more flexibility as to the geometry of the pump assembly 20 adapted for compact engine designs. In the depicted embodiment, the transmission 23 is one of a plurality of transmissions, with a second transmission 23′ drivingly engaging the second pump stage 40 and the third pump stage 50 to each other.
In some embodiments, such as shown in
In the depicted embodiment, the transmission gears 23A, 23B are shown as spur gears, but other geometries may be contemplated. For instance, conical gears of a transmission 23 may allow angular relative disposition of the shaft(s) of the drivingly engaged pump stages (e.g. 30, 40). That is, although not shown, a pump stage may include one or more shaft(s) extending angularly with respect to one or more shaft(s) of an adjacent pump stage. Such pump stages may be operatively engaged to each other via intermeshing conical gears and mounted respectively on a shaft of a first pump stage and a shaft of the second pump stage. The pump stages may thus be disposed at an angle with respect to each other, and operatively engaged via such transmission 23. The relative angle between the pump stages could vary depending on the embodiments and/or available space to fit the pump assembly 20 within the aircraft engine envelope, for instance.
The depicted pump assembly 20 may have a power input gear 24. The power input gear 24 may be coupled to any suitable power source for operation of the pump assembly 20, although not shown. The power input gear 24 in this embodiment is disposed at an axial end of the pump assembly 20 opposite the axial end of the pump assembly 20 at which the transmission 23 drivingly engaging the first and second pump stages 30, 40 is located. This may be different in other embodiments. As in the depicted embodiment of
Returning to
Although not shown, the embodiment of the pump assembly 20 shown in
Although part of the same pump assembly 20, the pump stages 30, 40, 50 may be associated to different functions, such as scavenge stage or pressure stage. A scavenge pump (or pump stage) receives used fluid from a component of the aircraft engine 1 (e.g. from a gearbox, or other components with lubrication, for instance), whereas a pressure pump (or pump stage) discharges fluid received from a fluid source (e.g. fluid reservoir) toward a component of the aircraft engine 1 that requires fluid to function (e.g. lubrication). For instance, in an embodiment a first pump stage 30 may be a pressure pump stage and a second pump stage 40 may be a scavenge pump stage. In some embodiments, the pressure pump stage may be operable to circulate fluid from one (e.g. a first) inlet port 21 to one outlet port 22 of the pump assembly 20 to a component of the aircraft engine 1. The scavenge pump stage may be operable to circulate fluid from another inlet port 21′ distinct from the inlet port 21 of the pressure pump stage, where such other inlet port 21′ may receive fluid from the same (or another) component of the aircraft engine 1. The scavenge pump stage may discharge fluid to another outlet port 22′ distinct from the outlet port 22 of the pressure pump stage.
Features of a first pump stage 30 will now be described. Corresponding (and/or similar) features of the other pump stages 40, 50 will be referred to later.
In the depicted embodiment, the pump chamber 31 of the first pump stage 30 defines a first flow path 31A. In the depicted embodiment, the first pump stage 30 includes shafts 32A, 32B mounted to the casing 20A for rotation about respective rotation axes R1, R2, with a pair of intermeshing gears 33A, 33B disposed in the flow path 31A of the first pump chamber 31. The intermeshing gears 33A, 33B define the rotating elements moving the volume of fluid within the pump chamber 31 to give motive flow to the fluid. During rotation, the intermeshing gears 33A, 33B in the fluid in the pump chamber 31 induces fluid circulation in the flow path 31A. Such pair of intermeshing gears 33A, 33B intermesh each other for reciprocal rotation. One intermeshing gear 33A of the first pump stage 30 is mounted on the first shaft 32A rotating about rotation axis R1 and may be regarded as a drive gear to impart rotation to the other gear 33B. Pump stages with such shafts and gears arrangement may be referred to as gear (or external gear) pumps (or stages of a gear pump).
Other types of pump arrangement may be contemplated in other embodiments. For instance, as shown in
Returning to
In the depicted embodiment, shafts 32A, 42A extend parallel to each other, though this is optional. The shafts 32A, 42A extend along respective rotation axes R1 and R3, with their rotation axes being parallel to each other. The shafts 32A, 42A are radially spaced apart from each other by a distance D1 (see
In the depicted embodiment, the transmission 23 drivingly engages shaft 32A in the first stage 30 and shaft 42A in the second pump stage 40. In other words, the transmission 23 forms a mechanical link between the shaft 32A of the first pump stage 30 and the shaft 42A of the second pump stage 40. The transmission 23 may therefore transmit torque from one shaft 32A to the other shaft 42A. Having a transmission 23 operatively engaging the pump stages 30, 40 may allow the pump stages 30 and 40 to be side by side as opposed to being axially stacks, which may result in a reduced axial footprint AFP of the pump assembly 20 in comparison to a pump assembly having a same number of stages but arranged in an axial stack. The transmission 23 may thus allow a radial disposition of the pump stages with respect to each other instead of an axial disposition along one shaft of the pump assembly 20, as shown in
The components of the third pump stage 50 are now described, similarly as above for the other pump stages 30, 40.
The pump chamber 51 defines a third flow path 51A. In the depicted embodiment, the flow path 51A extends from a fluid inlet port 21″ distinct from that of the flow paths 31A and 41A of the first and second pump stages 30, 40. The flow path 51A extends to a distinct fluid outlet port 22′ than that of the first and second pump stages 30, 40. Such flow path interaction(s) may be interchangeable in other embodiments. In the depicted embodiment, the third pump stage 50 includes shafts 52A, 52B mounted to the casing 20A for rotation about respective rotation axes R5, R6, with a pair of intermeshing gears 53A, 53B disposed in the flow path 51A of the third pump chamber 51. The third pair of intermeshing gears 52A, 52B intermeshing each other for joint rotation. The shaft 52A is rotatably supported relative to the casing 20A for rotation about a rotation axis R5 different than the rotation axis R1 of the shaft 32A of the first stage 30. One intermeshing gear 52A of the third pump stage 50 is mounted on the shaft 52A. The other intermeshing gear 52B of the third pump stage 50 is mounted on shaft 52B.
The second transmission 23′ drivingly engages the shaft 52A of the third pump stage 50 to the shaft 42A of the second pump stage 40, such that the second pump stage 40 and the third pump stage 50 are operatively engaged to each other via the second transmission 23′. The pump stages 30, 40, 50 may be said to be mounted in mechanical cascade (or in series) with respect to each other via the first and second transmissions 23, 23′. In an embodiment, none of R1, R2, R3, R4, R5 and R6 are coincident or coaxial. They may all be parallel to one another.
In some embodiments, the pump assembly 20 may include a pump stage disposed axially with respect to another pump stage. This will now be described with reference to
The embodiments described in this document provide non-limiting examples of possible implementations of the present technology. Upon review of the present disclosure, a person of ordinary skill in the art will recognize that changes may be made to the embodiments described herein without departing from the scope of the present technology. For example, the pump architecture described above with reference to various embodiments may be applied to gerotor pump or other types of rotating shaft pumps. Yet further modifications could be implemented by a person of ordinary skill in the art in view of the present disclosure, which modifications would be within the scope of the present technology.
