DESMODROMIC PUMP WITH RADIAL WINGS

Description

Technical Field

[0001] This presentation concerns a radial vane desmodromic pump and a fluid circuit for a turbomachine. Such a pump can be used, in particular, to pump oil from various components of a turbomachine in order to recover it and return it to the lubrication circuit; it can also be part of a fuel circuit. It can be used in all types of turbomachinery, including turbojet engines for both civil and military aircraft. Previous technique

[0002] Aircraft turbojets have many mechanical components that require lubrication: these include shafts, bearings and gearboxes such as the accessory gearbox, commonly called AGB (accessory gearbox), or the transfer gearbox, commonly called TGB (transfer gearbox).

[0003] These turbojet engines are equipped with a lubrication system that supplies oil to each of their components. A feed pump generates a flow of oil which is then divided into several lines to supply the various engine components.

[0004] To save oil, this lubrication circuit operates in a closed loop, with the oil delivered to each piece of equipment being recovered by gravity in sumps and then reinjected into the lubrication circuit by as many recovery pumps.

[0005] However, such a configuration is quite bulky and heavy, as a recovery pump is required for each sump. Consequently, the volume and mass of the lubrication system increase proportionally to the number of components to be lubricated, which is generally at least four. In particular, a new recovery pump is needed for each new component to be lubricated. And any additional mass represents additional fuel consumption for the engine.

[0006] To minimize this additional mass, it is now known to use certain types of pumps, such as desmodromic vane pumps or gerotor pumps, to implement these recovery pumps. In particular, these desmodromic vane pumps, whose vanes move radially relative to the shaft and are guided by the internal surface of the stator cavity, are especially compact and therefore have a relatively low mass for a given flow rate. Documents BE 883 004, FR 2 086 986, GB 2 006 342, and DE 35 10 681 describe examples of vane pumps; however, none of them describes a pump with two separate inlets leading to a single common outlet. Nevertheless, even greater gains are sought.

[0007] There is therefore a real need for a pump and fluid circuit that are free, at least in part, from the disadvantages inherent in the aforementioned known configuration. Description of the invention

[0008] The present description relates to a desmodromic radial vane pump according to claim 1.

[0009] Thus, thanks to this configuration, it is possible to obtain a desmodromic pump with radial vanes, benefiting from the compactness of this type of pump, equipped with two separate inlets. It is then possible to use a single pump to pump fluid from two different lines.

[0010] In particular, it is possible to use such a pump to pump the contents of two different sumps. This makes it possible to halve the number of pumps required, which greatly reduces the size and weight of the lubrication system and therefore reduces engine fuel consumption accordingly.

[0011] In some embodiments, the rotor comprises at least eight vanes. Indeed, although six vanes is the minimum functional number required to ensure three sealing segments between each inlet / outlet, it is preferable to use a larger number of vanes to reduce the size of these sealing segments and thus increase the size of the inlets. This reduces the pressure drop at the inlets, thereby increasing the pump's efficiency. In particular, the inventors determined that eight vanes offered the best compromise between the favorable increase in inlet size and the unfavorable increase in the mass and complexity of the vane assembly.

[0012] In some embodiments, the pallets are regularly spaced around the tree.

[0013] In some embodiments, each stator inlet extends over an angular sector of at least 25°, preferably at least 40°, and even more preferably at least 50°. As indicated above, the larger the inlets, the lower the pressure loss.

[0014] In some embodiments, the stator inlets have different angular sectors. This allows, if desired, for a different pumping flow rate to be set for each inlet. In particular, it would be possible in this way to mix two fluids in specific predetermined proportions.

[0015] In some embodiments, the stator output extends over an angular sector of at least 70°, preferably at least 130°, and even more preferably at least 140°.

[0016] In some embodiments, at least one stator inlet or outlet is axially divided into at least two orifices. This increases the stator's mechanical strength by providing a continuous axial ring of material between the two sets of orifices.

[0017] In some embodiments, the tree comprises a central cavity and a plurality of longitudinal slots opening into the central cavity, each pallet being engaged in a longitudinal slot. Like the pallets, these slots are arranged in diametrically opposite pairs. Each pallet thus slides within a separate slot, the pallet being guided by the edges of the slot in question. In particular, the height of the slots corresponds approximately to the height of the pallets, and the width of the slots corresponds approximately to the thickness of the pallets. Preferably, the number of slots corresponds to the number of pallets.

[0018] In some embodiments, all the pallets have the same height and the same maximum depth, this maximum depth being measured in the radial direction between the most proximal point of the pallet and its most distal point.

[0019] In some embodiments, the proximal edge of each paddle has protruding and recessed portions, each pair of paddles having a symmetrical profile distinct from the profile of other pairs of paddles. In this way, the paddles of each pair can be in contact with each other without interfering with other pairs of paddles. In this way, the first paddle of the pair can push the second paddle of the pair outward when it is itself pushed inward by the inner surface of the cavity forming the cam surface; and vice versa.Here, it is necessary to understand that the profile of the pairs of pallets is oriented, that is to say that its orientation in the axial direction is taken into account: it is thus possible that two pairs of pallets have profiles that are symmetrical with respect to a plane transverse to the direction of the shaft but nevertheless different because they are oriented differently, one "head up", the other "head down".

[0020] In some embodiments, the projecting portions of each pair of pallets extend to the recessed portions of all other pairs of pallets. In this way, the projecting portions of the different pairs of pallets can come into contact without interfering with each other.

[0021] In some embodiments, the proximal edge of each pallet has at least two, and preferably three, protruding portions. This increases the stability of the pallet when it is pushed by the opposite pallet.

[0022] In some embodiments, the distance separating two projecting portions is the same for all pallets.

[0023] In some embodiments, the pump is configured to generate an output flow rate between 300 and 20,000 l / h, preferably between 1,000 and 15,000 l / h.

[0024] The present presentation also relates to a fluid circuit, comprising at least one pump according to any one of the preceding embodiments.

[0025] In some embodiments, the fluid circuit comprises two separate lines, the first line being connected to the first inlet of the pump and the second line being connected to the second inlet.

[0026] In some embodiments, the first and second lines are designed to carry the same fluid.

[0027] In some embodiments, the first and second lines are designed to carry two different fluids.

[0028] In some embodiments, the pressure of the line connected to the first inlet of the pump is different from the pressure of the line connected to the second inlet of the pump.

[0029] In some embodiments, the fluid circuit is a lubrication circuit. The fluid flowing through the circuit is thus a lubricant, for example oil.

[0030] The present presentation also relates to a turbomachine, comprising a fluid circuit according to any one of the preceding embodiments.

[0031] In this discussion, the terms "longitudinal," "transverse," "lower," "upper," and their derivatives are defined with respect to the shaft axis; the terms "axial," "radial," "tangential," "inner," "outer," "proximal," and "distal" are also defined with respect to the shaft axis. An "axial plane" is understood to be a plane passing through the shaft axis, and a "radial plane" is understood to be a plane perpendicular to this axis. Finally, the terms "upstream" and "downstream" are defined with respect to the fluid flow within the fluid circuit. Furthermore, it should be noted that a cylindrical surface can be generated by any direction curve, such that, unless otherwise specified, a cylinder is not necessarily a cylinder of revolution.

[0032] The aforementioned features and advantages, as well as others, will become apparent upon reading the detailed description that follows, along with examples of the pump and fluid circuit implementations. This detailed description refers to the attached drawings. Brief description of the drawings

[0033] The attached drawings are schematic and are primarily intended to illustrate the principles of the presentation.

[0034] In these drawings, from one figure to another, identical elements (or parts of elements) are identified by the same reference symbols. [ Fig. 1 ] There figure 1 is a diagram of an example fluid circuit as presented. Fig. 2 ] There figure 2 is a perspective view of an example of a pump according to the exposition. Fig. 3 ] There figure 3 is a radial cross-sectional view of the pump of the figure 2 . [ Fig. 4 ] There figure 4 is a side view, inlet side, of the pump of the figure 2 . [ Fig. 5 ] There figure 5 is a side view, outlet side, of the pump of the figure 2 . [ Fig. 6 ] There figure 6 schematically represents the different pairs of vanes of the pump. figure 2 . Description of the implementation methods

[0035] To make the explanation more concrete, an example of a pump and fluid circuit is described in detail below, with reference to the attached drawings. It should be noted that the invention is not limited to this example.

[0036] There figure 1 illustrates schematically an example of a lubrication circuit for a turbomachine.

[0037] This lubrication circuit 1 supplies oil to a plurality of equipment 3a, 3b, 3c, 3d. The lubrication circuit 1 comprises, from upstream to downstream, a reservoir 20, a strainer 21, a supply pump 22, a filter 23, a fuel / oil exchanger 24, an air / oil exchanger 25, the equipment 3a, 3b, 3c, 3d, each provided on a separate supply branch 2a, 2b, 2c, 2d in parallel with each other, strainers 26 and recovery pumps 30, downstream of the equipment 3a, 3b, 3c, 3d, allowing the oil from each supply branch 2a, 2b, 2c to be returned to the reservoir 20.

[0038] In this example, components 3a, 3b, 3c, and 3d may include gearboxes, and in particular the turbomachine's accessory gearbox. More specifically, the lubrication circuit 1 comprises a plurality of nozzles located inside the accessory gearbox to spray oil onto its gears and onto at least some of the internal walls of its housing. The sprayed oil is then collected in a sump at the lowest point of the accessory gearbox. Components 3a, 3b, 3c, and 3d may also include other gearboxes, housings for other accessories, or bearing enclosures. Some of these components 3a, 3b, 3c, and 3d may be driven by the accessory gearbox via a mechanical transmission.It goes without saying that the lubrication circuit 1 can supply any number of equipment 3a, 3b, 3c, 3d and not just four as shown on the diagram. figure 1 .

[0039] A particular feature of the recovery pumps 30 described herein is that they have two separate inlets for a common outlet. Thus, in the present example, which includes four pieces of equipment 3a, 3b, 3c, 3d, the lubrication circuit 1 includes only two recovery pumps 30, the first being connected to the recovery lines 27a, 27b of the first two pieces of equipment 3a, 3b and the second being connected to the recovery lines 27c, 27d of the last two pieces of equipment 3c, 3d.

[0040] A recovery pump 30 will now be described in more detail with reference to figures 2 à 6 All 30 recovery pumps are identical or at least have a similar structure, even if they are not configured in the same way.

[0041] This recovery pump 30 comprises a stator 40 and a rotor 50. The stator 40 has a generally cylindrical shape of revolution with main axis A. It comprises a cylindrical cavity 41 whose central axis B is parallel but eccentric with respect to the main axis A of the stator.

[0042] The rotor 50 includes a shaft 51, extending along the main axis A and thus longitudinally passing through the cavity 41 of the stator 40. This shaft 51 carries a plurality of vanes 52, here eight in number, arranged in pairs 52a, 52b, 52c, 52d.

[0043] These 52 pallets are more visible on the figure 6 They all have the same height and maximum depth. Their distal edges 53 are all identical: they are straight and extend in the axial direction along the entire height of the pallet 52. The proximal edges 54 of each pair 52a, 52b, 52c, 52d of pallets 52, however, have different profiles. More specifically, these proximal edges 54 have projecting portions 54s and recessed portions 54r.

[0044] The two pallets 52 of the same pair 52a, 52b, 52c, 52d have the same profile such that their protruding portions 54s are in contact with each other when assembled on the shaft 51. On the other hand, the protruding portions 54s of each pair of pallets 52a, 52b, 52c, 52d coincide with recessed portions 54r for all other pairs of pallets 52a, 52b, 52c, 52d when assembled on the shaft 51 such that the protruding portions 54s of all pairs 52a, 52b, 52c, 52d can come into contact without being hindered by the protruding portions 54s of the other pairs 52a, 52b, 52c, 52d.

[0045] In this example, each pallet 52 has three projecting portions 54s, each with a height equal to 1 / 12 of the total height of the pallet 52. Furthermore, each projecting portion 54s is separated from its neighbor by a distance equal to 3 / 12 of the total height of the pallet 52. It can then be observed that the profile of each pair 52a, 52b, 52c, 52d comprises the same pattern offset by a distance equal to 1 / 12 of the total height of the pallet 52. It can also be noted that, thanks to the symmetries, there are only two different geometries of pallet 52, which simplifies manufacturing.

[0046] To allow the assembly of the pallets 52, the shaft 51 has an internal cavity 55 and a plurality of slots 56, the number of which is equal to the number of pallets 52, spaced regularly around the shaft 51. Each slot 56 extends axially and has dimensions corresponding substantially to the height and thickness of the pallets 52.

[0047] Each pallet 52 is thus engaged in a light 56 ​​which holds it and guides it in translation. Thus each pallet 52 is radially mobile in translation, along a diametrical plane of the shaft 51.

[0048] The internal surface 42 of the stator cavity 40 forms a cam surface which, as the shaft 51 rotates, acts on the vanes 52. When, for a given vane 52, the distance between the shaft 51 and the cam surface 42 decreases, the cam surface 42 pushes the vane 52 inwards as the distance decreases, thus maintaining the seal at the end of the vane 52. Then, when, for the same vane 52, the distance between the shaft 51 and the cam surface 42 increases again, the distance between the shaft 51 and the cam surface 42 decreases symmetrically for the opposite vane 52 of the same pair 52a, 52b, 52c, 52d: consequently, the opposite vane 52 is pushed inwards and then pushes the first vane 52 outwards, thus maintaining contact with the cam surface 42 and therefore the end seal. of palette 52. This results in a desmodromic mechanism.

[0049] The stator 40 also includes a first inlet 43, a second inlet 44 and an outlet 45 made radially in the wall 46 surrounding the cavity 41 so as to put different sectors of the cavity 41 into communication with the outside.

[0050] By turning in the counterclockwise direction, that is to say according to the direction of rotation of the shaft 51, from the origin point O where the distance between the shaft 51 and the cam surface 42 is minimal, we thus find a first sealing sector 47, the first inlet 43, a second sealing sector 47, the second inlet 44, a third sealing sector 47 then, in the second half where the distance between the shaft 51 and the cam surface 42 decreases, the outlet 45 then we find the first sealing sector 47 and the origin point O.

[0051] The sealing sectors 47 extend over an angular sector at least equal to, and preferably substantially equal to, the angle separating two consecutive pallets 52, i.e., 45° in the present example. In the present example, each inlet 43, 44 extends over an angular sector θ, φ of 45°, while the outlet 45 extends over an angular sector ψ of 135°.

[0052] We can also observe on the figures 4 et 5 that, for structural reasons, each inlet 43, 44 as well as the outlet 45 is divided into two orifices 43a, 43b, 44a, 44b, 45a, 45b separated axially by a continuous ring 48 devoid of any opening.

[0053] Although the present invention has been described with reference to specific embodiments, it is evident that modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the claims. In particular, individual features of the various embodiments illustrated / mentioned can be combined in additional embodiments. Therefore, the description and drawings should be considered in an illustrative rather than restrictive sense.

[0054] It is also evident that all the characteristics described with reference to a process are transposable, alone or in combination, to a device, and conversely, all the characteristics described with reference to a device are transposable, alone or in combination, to a process.

Claims

1. A desmodromic radial vane pump for a turbomachine, comprising: a stator (40), including a cylindrical cavity (41), and a rotor (50), including a shaft (51), passing eccentrically through the cavity (41) of the stator (40), and a plurality of vanes (52), arranged in pairs (52a, 52b, 52c, 52d), movably assembled on the shaft (51) and flush with the surface of the cavity (41) of the stator (40), the vanes (52) of the same pair (52a, 52b, 52c, 52d) extending in contact with each other in the same diametral plane of the shaft (51) while being movable in said diametral plane relative to the shaft (51), wherein the rotor (50) comprises at least six vanes (52), and characterized in that the stator (40) comprises two distinct inlets (43, 44) and a common outlet (45), sealing segments (47) being disposed between the two distinct inlets (43, 44) and between each of the two distinct inlets (43, 44) and the common outlet (45).

2. The pump according to claim 1, wherein the rotor (50) comprises at least eight vanes (52).

3. The pump according to claim 1 or 2, wherein each inlet (43, 44) of the stator (40) extends over an angular sector (θ, φ) at least equal to 25°, preferably at least equal to 40°, even more preferably at least equal to 50°.

4. The pump according to any one of claims 1 to 3, wherein the inlets (43, 44) of the stator (40) have different angular sectors (θ, φ).

5. The pump according to any one of claims 1 to 4, wherein the shaft (51) comprises a central cavity (55) and a plurality of longitudinal slots (56) opening out into the central cavity (55), each vane (52) being engaged in a longitudinal slot (56).

6. The pump according to any one of claims 1 to 5, wherein the proximal edge (54) of each vane (52) has protruding portions (54s) and recessed portions (54r), each pair of vanes (52a, 52b, 52c, 52d) having a symmetrical profile, distinct from the profile of the other pairs of vanes (52a, 52b, 52c, 52d), and wherein the protruding portions (54s) of each pair of vanes (52a, 52b, 52c, 52d) extend to the level of recessed portions (54r) of all the other pairs of vanes (52a, 52b, 52c, 52d).

7. A fluid circuit, comprising at least one pump (30) according to any one of claims 1 to 6.

8. The fluid circuit according to claim 7, wherein the pressure of the line (27b) connected to the first inlet (43) of the pump (30) is different from the pressure of the line (27a) connected to the second inlet (44) of the pump (30).

9. A turbomachine, comprising a fluid circuit (1) according to claim 7 or 8.