Turbomachine lubrication unit and method of manufacture
An aircraft bypass turbojet engine lubrication unit includes from three to five superposed pumps, a body housing the pumps and an internal passage in the body for communicating with each of the pumps. The material of the body exhibits a stack of layers in a direction of stacking, the pumps being housed in the said stack of layers. The passage exhibits an end in the direction of stacking of the layers and an internal profile, for example triangular, with two straight lines which form the said end and which are inclined with respect to the stacked layers. The lubrication unit may be manufactured by additive manufacturing in layers.
1. A lubrication unit for a turbojet engine, the lubrication unit comprising:
at least two pumps; and
a body which exhibits a passage communicating with each of the pumps;
wherein the body is made by additive manufacturing thus exhibiting a stack of layers in a direction of stacking, the pumps being housed in the said stack of layers;
wherein the passage comprises an internal surface having a first ruled surface and a second ruled surface, both ruled surfaces comprising a plurality of first straight lines and a plurality of second straight lines, each of the first straight lines and each of the second straight lines being inclined with respect to the direction of stacking,
wherein the passage exhibits an end in the direction of stacking of the layers, and a profile with a first straight line of plurality of first straight lines and a second straight line of the plurality of second straight lines which form the said end.
2. The lubrication unit according to claim 1 , wherein the first and second ruled surfaces are a first place and a second plane.
3. The lubrication unit according to claim 1 , wherein the profile forms a triangle or a pentagon with a principal elongation in the direction of stacking, perpendicular to the layers.
4. The lubrication unit according to claim 1 , wherein the internal surface of the passage further comprises:
a third ruled surface made of a plurality of third straight lines, wherein a third straight line of the plurality of third straight lines is inclined with respect to the first straight line of the plurality of first straight lines and with respect to the second straight line of the plurality of second straight lines, and is inclined with respect to the layers, the said third straight line of the plurality of third straight lines connecting the first straight line of the plurality of first straight lines to the second straight line of the plurality of second straight lines.
5. The lubrication unit according to claim 1 , wherein the end of the profile comprises:
a fillet radius connecting the first straight line of the plurality of first straight lines to the second straight line of the plurality of second straight lines, the fillet radius being less than or equal to: 10 mm or 4 mm.
6. The lubrication unit according to claim 1 , wherein the passage extends over the majority of the body in the direction of stacking.
7. The lubrication unit according to claim 1 , wherein the first straight line of the plurality of first straight lines is inclined by at most 15° with respect to the direction of stacking.
8. The lubrication unit according to claim 1 , wherein the second straight line of the plurality of second straight lines is inclined by at least 30° with respect to the layers.
9. The lubrication unit according to claim 1 , wherein the body exhibits a main housing accommodating the at least two pumps, the housing exhibiting a main axis in the direction of stacking.
10. The lubrication unit according to claim 9 , wherein the direction of stacking is more inclined with respect to the first straight line of the plurality of first straight lines and/or with respect to the second straight line of the plurality of second straight lines than with respect to the main axis.
11. The lubrication unit according to claim 1 , wherein each pump comprises:
a rotor with an axis of rotation in the direction of stacking, the rotors possibly being superposed in the direction of stacking.
12. The lubrication unit according to claim 1 , further comprising:
a drive shaft for driving the pumps, the drive shaft passing through most of the layers.
13. The lubrication unit according to claim 1 , wherein the at least two pumps comprise:
at least three pumps or at least five pumps communication directly with the passage.
14. The lubrication unit according to claim 1 , further comprising:
at least one auxiliary well or at least two auxiliary wells with auxiliary axes arranged transversely with respect to the layers.
15. The lubrication unit according to claim 1 , further comprising:
a duct in which the passage is formed and which has a triangular or pentagonal external profile.
16. The lubrication unit according to claim 15 , wherein the body exhibits two opposite faces, the duct extending from one opposite face to the other.
17. The lubrication unit according to claim 15 , wherein the duct comprises:
a principle elongation forming a first curvature and then a second curvature in the opposite direction to the first curvature.