The present invention in particular relates to a planet carrier for a speed-reducing unit with an epicyclic gear train, this planet carrier comprising a cage for receiving the sun gear and planet gears of the reduction gear.
The state of the art comprises, in particular, document US-A1-2015/0247566.
A speed-reducing unit with an epicyclic gear train of an aircraft turbine engine conventionally comprises a sun gear coupled with a first shaft and a ring gear extending around the sun gear. Planet gears are arranged between the sun gear and the ring gear and are meshed together and carried by a planet carrier coupled with a second shaft.
There are several types of planet carrier.
This second cage planet carrier technology is advantageous in that the impeller transfers less force and is therefore less stressed in operation. Moreover, the mounting of the impeller is easier here and requires less complex tools than for a cantilevered impeller planet carrier.
However, a cage planet carrier of the current art is relatively bulky in the axial direction. The impeller provided on the cage of the planet carrier is furthermore subjected to wear phenomena at its interfaces with the other parts, which limit its lifespan.
The present invention proposes an improvement of this second technology, which brings a simple, effective and economical solution to at least one of these problems.
According to the invention, this aim is achieved with a planet carrier for a speed-reducing unit with an epicyclic gear train for a turbine engine, said planet carrier comprising a cage defining an internal space for mounting a central sun gear of rotation axis A and an annular row of planet gears arranged around the axis A and meshed with said sun gear, said sun gear comprising means for coupling to a first shaft, said cage comprising two substantially parallel annular walls centred on said axis A and a cylindrical wall connecting said annular walls to their external periphery, a first of said annular walls being connected to a substantially cylindrical body comprising means for coupling to a second shaft, characterised in that a second of said annular walls is formed of a single part with lubrication means, which comprise an annular groove for receiving oil formed in said second wall and extending to the periphery of a central opening centred on the axis A of the second wall, said annular groove radially opening inwards.
The integration of the lubrication means directly in the cage makes it possible to remove the impeller of the prior art and, due to this, to reduce the axial bulkiness of the planet carrier.
The planet carrier according to the invention can comprise one or more of the following features, taken individually from one another, or in combination with one another:
The present invention also relates to a turbine engine comprising a speed-reducing unit with an epicyclic gear train whose planet carrier is such as described above.
The turbine engine can comprise means for supplying lubricant to said groove, which comprise a series of injectors which are arranged around said axis A, and which pass through said opening. The injectors are preferably configured to spray lubricant radially outwards directly into said groove.
Other features and advantages will emerge from the following description of a non-limiting embodiment of the invention in reference to the appended drawings, wherein:
The annular wall 136 is secured to a substantially cylindrical body 142, partially visible, comprising meshing means with a shaft such as a fan shaft of the turbine engine. The coupling means are, for example, longitudinal slots of the type of those which can be seen in
In the example represented, the cylindrical wall 140 is perforated and comprises through-holes 143 in the radial direction.
The wall 138 comprises a central opening 144 centred on the axis A and a series of orifices 146 regularly distributed around the axis A, the opening 144 and the orifices 146 passing through in the axial direction.
The orifices 146 serve for mounting the rotation axes 148 of the planet gears 150 schematically represented in
Although this cannot be seen, the planet gears 150 rotationally mounted on the axes 148 have their external peripheries partially passing through the through-holes 143 in view of their meshing with an external ring gear of the reduction gear intended to surround the cage 134.
The planet gears 150 mesh with the sun gear 151, which comprises internal rectilinear slots for coupling to another shaft such as a turbine shaft.
The central opening 144 is delimited externally by an annular portion of excess thickness of the wall 138, wherein is formed an annular groove 158. This groove 158 extends around the axis A and opens out radially inwards. Its radially external bottom wall comprises orifices in fluidic communication with radial channels 160, on the one hand, and radial ducts 162, on the other hand.
Inside the groove 158, fins 164 can be arranged substantially radial to facilitate the radial flow of lubricant form the internal periphery of the groove up to its bottom wall and the abovementioned orifices.
In the represented example, the number of channels 160 is equal to the number of ducts 162, which is equal to the number of axes 148 and of planet gears 150. This number is here five. The channels 160 are regularly distributed around the axis A and the ducts 162 are regularly distributed around the axis A, each duct 162 being arranged between two adjacent channels 160. The ducts and channels are formed in excess thicknesses 165, 166 of the wall 138. The excess thicknesses 165, wherein the channels 160 are formed, radially extend outwards from the excess thickness 168, wherein the groove 158 is formed. The excess thicknesses 166, wherein the ducts 162 are formed, radially extend between the excess thickness 168 and the bosses 170 of the wall 138, where the orifices 146 are formed.
Each of the channels 160 communicates at its radially external end with a longitudinal end of a tubular nozzle 172 which can be seen, in particular, in
Each of the ducts 162 communicates at its radially external end with a longitudinal end of a supply tube 178 which can be seen in
Annular gaskets 188 are advantageously provided around the tube. One or more of the first gaskets can be located at the open longitudinal end of the tube and intended to engage with the wall 138, and other gaskets can be located on either side of the slot 186 (or bores), respectively, and intended to engage with the corresponding axis 148 (see
In the example represented, each tube 178 also passes through an annular cover 189 returned and fixed, for example by screws, on the wall 138, on the side opposite the planet gears 150. Each cover 189 covers the corresponding boss 170 of the wall 138 and is intended to centre the corresponding axis 148 in the orifice 146 of the wall 138.
The invention presents numerous advantages with respect to the prior art: a reduced axial bulkiness, the removal of a countersinking part (impeller) which is difficult to machine, due to the cage, which is easier to machine by turning, less statically indeterminate during mounting, no more fretting problem in the impeller, the possibility of having the nozzles closer to the sun gear, the increased rigidity of the planet carrier, shorter and lighter nozzles (fewer dynamic problems), etc.
Number | Date | Country | Kind |
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1753669 | Apr 2017 | FR | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2018/060804 | 4/26/2018 | WO | 00 |