Multi-profile coupling of pumps in a lubrication arrangement

Description

technical field

[0001] The present invention relates to the rotational coupling between two rotary pumps of an aircraft turbomachine lubrication unit. Previous art

[0002] The pumps in aircraft turbomachinery lubrication units are typically stacked, and their shafts are rotationally coupled to achieve rotary drive. A known method for this coupling is via splines. US4631009 A provides an example.

[0003] The splines are machined by electrical discharge machining (EDM) or broaching. These operations are lengthy and complex. Sometimes, the splines are so small that it is necessary to use small tools that deform, making machining virtually impossible. Summary of the invention

[0004] One object of the present invention is to obtain a lubrication unit that is easier to manufacture. To this end, the invention proposes a lubrication unit for an aircraft turbomachine comprising: a first pump comprising a first shaft; a second pump comprising a second shaft; characterized in that the first shaft and the second shaft are mechanically coupled via at least one coupling by polygonal profiles.

[0005] The coupling using polygonal profiles can be machined by milling (female) or turning (male). It is therefore easier to manufacture than the splined coupling.

[0006] Coupling by polygonal profiles is known to those skilled in the art, in particular by the DIN 32711 parts 1 and 2 standards.

[0007] According to one embodiment, the first shaft and the second shaft are coupled in rotation via at least one coupling by polygonal profiles.

[0008] According to one embodiment, the second shaft is mechanically coupled to the first shaft by a coupling element, and the coupling element includes a first end forming a male part of a first coupling by polygonal profiles and the first shaft includes a first end forming a female part of said first coupling by polygonal profiles.

[0009] According to one embodiment, the male and female parts are separated from each other.

[0010] The fact that the male and female parts are disjointed allows the gap between them to take over the misalignment defects of the trees.

[0011] According to a preferred embodiment, the invention relates to a lubrication unit for an aircraft turbomachine comprising: a first pump comprising a first shaft; a second pump comprising a second shaft mechanically coupled to the first shaft by a coupling element; characterized in that the coupling element comprises a first end forming a male part of a first coupling by polygonal profiles and the first shaft comprises a first end forming a female part of said first coupling by polygonal profiles, said male and female parts being disjoint from each other.

[0012] According to one embodiment, the profile of the first end of the coupling element and the profile of the first end of the first tree satisfy the following equalities: x α = R m − e ⋅ cos n ⋅ α ⋅ cos n ⋅ α − n ⋅ e ⋅ sin n ⋅ α ⋅ sin α y α = R m − e ⋅ cos n ⋅ α ⋅ sin n ⋅ α + n ⋅ e ⋅ sin n ⋅ α ⋅ cos α Or α is a variable, x And y are Cartesian coordinates, R m is a first parameter, e is a second parameter, and n is a third integer parameter greater than or equal to 3.

[0013] R mand e are smaller for the first end of the coupling element than for the first end of the first tree so that the female part is wider than the male part. n has the same value for the first end of the coupling element as for the first end of the first tree.

[0014] According to one embodiment, the male and female parts of the first coupling by polygonal profiles have three sides. The male and female parts are essentially triangles with rounded corners. Therefore, n = 3 in the equalities.

[0015] According to one embodiment, the male and female parts of the first coupling by polygonal profiles are separated by at least 10 µm.

[0016] According to one embodiment, the coupling element is one piece with the second shaft.

[0017] According to one embodiment, the second tree comprises a first end joined to a second end of the coupling element.

[0018] According to one embodiment, the coupling element is a different part of the second shaft.

[0019] According to one embodiment, the coupling element comprises a second end forming a male part of a second coupling by polygonal profiles and the second shaft comprises a first end forming a female part of said second coupling by polygonal profiles, said male and female parts being disjoint from each other.

[0020] According to one embodiment, the profile of the second end of the coupling element and the profile of the first end of the second tree satisfy the following equalities: x α = R m − e ⋅ cos n ⋅ α ⋅ cos n ⋅ α − n ⋅ e ⋅ sin n ⋅ α ⋅ sin α y α = R m − e ⋅ cos n ⋅ α ⋅ sin n ⋅ α + n ⋅ e ⋅ sin n ⋅ α ⋅ cos α Or α is a variable, x And y are Cartesian coordinates, R mis a first parameter, e is a second parameter, and n is a third integer parameter greater than or equal to 3.

[0021] R m And e are smaller for the second end of the coupling element than for the first end of the second shaft. n has the same value for the second end of the coupling element as for the first end of the second tree.

[0022] According to one embodiment, the male and female parts of the second coupling by polygonal profiles have three sides.

[0023] According to one embodiment, the male and female parts of the second coupling by polygonal profiles are separated by at least 10 µm.

[0024] According to one embodiment, the first and second pumps are vane pumps.

[0025] According to one embodiment, the first and second pumps are desmodromic vane pumps or gerotor pumps.

[0026] According to one embodiment, the lubrication group further comprises a third pump comprising a third shaft mechanically coupled to the second shaft by another coupling element, in which the other coupling element comprises another first end forming a male part of another coupling by polygonal profiles and the second shaft comprises a second end forming a female part of said other coupling by polygonal profiles, the male and female parts of said other coupling by polygonal profiles being disjointed from each other.

[0027] The invention further proposes an aircraft comprising a lubrication group as described in this document. Brief description of the figures

[0028] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, for an understanding of which reference should be made to the attached figures, among which: there figure 1 is a diagram of a lubrication group compatible with the invention, the figure 2 is a diagram of another lubrication group compatible with the invention, the figure 3 is a cross-sectional view of a coupling using polygonal profiles compatible with the invention, the figure 4 is a cross-sectional view of a polygonal profile compatible with the invention, and the figure 5 is a cross-sectional view of another polygonal profile compatible with the invention. Embodiments of the invention

[0029] The present invention is described with particular embodiments and references to figures, but the invention is not limited by them. The drawings or figures described are schematic only and are not limiting. Furthermore, the functions described can be performed by structures other than those described in this document.

[0030] In the context of this document, the terms "first" and "second" serve only to differentiate the different elements and do not imply any order between these elements.

[0031] In the figures, identical or analogous elements may bear the same references.

[0032] There figure 1This illustrates a lubrication unit 1 according to an embodiment of the invention. It comprises a first pump 10 including a first shaft 11 and a second pump 20 including a second shaft 21. The shafts 11 and 21 are mechanically coupled in rotation such that one of them can drive the other in rotation. This coupling is achieved via a coupling element 30 which comprises a first end 31 and a second end 32, opposite the first end 31.

[0033] The first shaft 11 comprises a first end 12. The second shaft 21 comprises a first end 22 and a second end 23. The first end 31 of the coupling element 30 is engaged in the first end 12 of the first shaft 11. The first end 31 of the coupling element 30 thus forms a male portion 41 of a first coupling by polygonal profiles 40 (which will be described with reference to the figure 3), the first end 12 of the first tree 11 forming a female part 42 of said first coupling by polygonal profiles 40.

[0034] In the implementation of the figure 1 The second end 32 of the coupling element 30 is engaged in the first end 22 of the second shaft 21. The second end 32 of the coupling element 30 thus forms a male part 41 of a second coupling by polygonal profiles 40 (which will be described with reference to the figure 3 ), the first end 22 of the second tree 21 forming a female part 42 of said second coupling by polygonal profiles 40.

[0035] In the implementation of the figure 2 , the second end 32 of the coupling element 30 is joined to the first end 22 of the second shaft 21 so that the coupling element 30 and the second shaft 21 form a single piece.

[0036] The lubrication group 1 may include a third pump, a fourth, etc. The pumps are stacked, and their shafts are rotationally coupled via polygonal profile couplings 40. For example, a third shaft of a third pump may be mechanically coupled to the second end 23 of the second shaft 22 by another coupling element, which includes another first end. The other first end forms a male portion of another polygonal profile coupling, and the second end 23 of the second shaft 22 forms a female portion of said other polygonal profile coupling.

[0037] Pumps 10, 20 are preferably vane pumps, for example desmodromic, or gerotor pumps.

[0038] There figure 3 is an example of coupling by polygonal profiles 40 between a male part 41 and a female part 42 disjointed from each other. The coupling 40 illustrated by the figure 3This may be a first (references 12 and 31 correspond to this), a second, and / or another coupling by polygonal profiles of this disclosure. The fact that the male part 41 and the female part 42 are disjoint implies that they are not fixed to each other. Furthermore, even if they may be in contact during training, at rest there is a space 45 around the male part 41, which separates it from the female part 42. The distance 46 between the male part 41 and the female part 42 can be at least 10 µm, preferably at least 100 µm. This distance 46 is measured in a cross-sectional plane, for example when the male parts 41 and 42 are aligned on the same axis.

[0039] There figure 4This shows a triangular polygonal profile, with a Cartesian coordinate system (x, y) and a polar coordinate system (r, ϕ). In general, a polygonal profile is defined by the following equalities in Cartesian coordinates: x α = R m − e ⋅ cos n ⋅ α ⋅ cos n ⋅ α − n ⋅ e ⋅ sin n ⋅ α ⋅ sin α y α = R m − e ⋅ cos n ⋅ α ⋅ sin n ⋅ α + n ⋅ e ⋅ sin n ⋅ α ⋅ cos α

[0040] In polar coordinates, this translates to ρ α = R m − e ⋅ cos n ⋅ α 2 + n ⋅ e ⋅ sin n ⋅ α 2 Φ α = α + arctan n ⋅ e ⋅ sin n ⋅ α R m − e ⋅ cos n ⋅ α

[0041] α is a variable, R m is a first parameter, e is a second parameter, and n is a third parameter. n is an integer greater than or equal to 3. 3 is required for the figure 4 (triangular polygonal profile), and 4 for the figure 5 (polygonal profile in quadrilateral). α varies in such a way as to traverse the curve of the polygonal profile. n is identical for the male part 41 and the female part 42. R m And eare smaller for the male part 41 than for the female part 42. In other words, the female part 42 has a wider profile than the male part 41.

[0042] In other words, the invention relates to a lubrication group 1 comprising two pumps 10, 20 whose shafts 11, 21 are coupled in rotation via at least one coupling by polygonal profiles 40.

[0043] The present invention has been described in relation to specific embodiments, which are purely illustrative and should not be considered limiting. In general, the present invention is not limited to the examples illustrated and / or described above. The use of the verbs "to include," "to comprise," or any other variant thereof, as well as their conjugations, does not in any way preclude the presence of elements other than those mentioned. The use of the indefinite article "a," "an," or the definite article "it," "a," or "I" to introduce an element does not preclude the presence of a plurality of such elements. The reference numbers in the claims do not limit their scope.

Claims

1. Lubrication assembly (1) for an aircraft turbine engine comprising: - a first pump (10) comprising a first shaft (11); - a second pump (20) comprising a second shaft (21); characterized in that the first shaft (11) and the second shaft (21) are mechanically coupled by means of at least one polygonal profile (40) coupling.

2. Lubrication assembly according to claim 1, wherein the first shaft (11) and the second shaft (21) are rotatably coupled by means of the at least one polygonal profile (40) coupling.

3. Lubrication assembly according to claim 1 or 2, wherein the second shaft (21) is mechanically coupled to the first shaft (11) by a coupling element (30), and wherein the coupling element (30) comprises a first end (31) forming a male part (41) of a first polygonal profile (40) coupling and the first shaft (11) comprises a first end (12) forming a female part (42) of said first polygonal profile (40) coupling.

4. Lubrication assembly according to the preceding claim, wherein said male (41) and female (42) parts are separated from one another.

5. Lubrication assembly according to any one of claims 3 or 4, wherein the profile of the first end (31) of the coupling element (30) and the profile of the first end (12) of the first shaft (11) satisfy the following equalities: x α = R m − e ⋅ cos n ⋅ α ⋅ cos n ⋅ α − n ⋅ e ⋅ sin n ⋅ α ⋅ sin α y α = R m − e ⋅ cos n ⋅ α ⋅ sin n ⋅ α + n ⋅ e ⋅ sin n ⋅ α ⋅ cos α where a is a variable, x and y are Cartesian coordinates, Rm is a first parameter, e is a second parameter, and n is a third integer parameter, greater than or equal to 3.

6. Lubrication assembly according to any one of claims 3 to 5, wherein the male part and the female part of the first polygonal profile (40) coupling have three sides.

7. Lubrication assembly according to any one of claims 3 to 6, wherein the male part and the female part of the first polygonal profile (40) coupling are distant by at least 10µm.

8. Lubrication assembly according to any one of claims 3 to 7, wherein the coupling element (30) is a part with the second shaft (21).

9. Lubrication assembly according to the preceding claim, wherein the second shaft (21) comprises a first end (22) joined to a second end (32) of the coupling element (30).

10. Lubrication assembly according to any one of claims 3 to 7, wherein the coupling element (30) is a part which is different from the second shaft (21).

11. Lubrication assembly according to the preceding claim, wherein the coupling element (30) comprises a second end (32) forming a male part (41) of a second polygonal profile (40) coupling and the second shaft (21) comprises a first end (22) forming a female part (42) of said second polygonal profile (40) coupling, said male (41) and female (42) parts being separated from one another.

12. Lubrication assembly according to the preceding claim, wherein the profile of the second end (32) of the coupling element (30) and the profile of the first end (22) of the second shaft (21) satisfy the following equalities: x α = R m − e ⋅ cos n ⋅ α ⋅ cos n ⋅ α − n ⋅ e ⋅ sin n ⋅ α ⋅ sin α y α = R m − e ⋅ cos n ⋅ α ⋅ sin n ⋅ α + n ⋅ e ⋅ sin n ⋅ α ⋅ cos α where α is a variable, x and y are Cartesian coordinates, Rm is a first parameter, e is a second parameter, and n is a third integer parameter greater than or equal to 3.

13. Lubrication assembly according to any one of the preceding claims, wherein the first (10) and second (20) pumps are vane pumps, preferably desmodromic vane pumps or gerotor pumps.

14. Lubrication assembly according to any one of the preceding claims, further comprising a third pump comprising a third shaft, mechanically coupled to the second shaft (21) by another coupling element, wherein the other coupling element comprises another first end forming a male part and another polygonal profile coupling and the second shaft (21) comprises a second end (23) forming a female part of said other polygonal profile coupling, the male and female parts of said other polygonal profile coupling being separated from one another.

15. Aircraft comprising a lubrication assembly according to any one of the preceding claims.