Propeller comprising at least one blade holding system comprising at least one transverse groove

Abstract

Propeller comprising at least one blade holding system comprising at least one transverse groove The invention relates to a propeller which comprises a hub (42), blades (44) each provided with a root (44.1), a pivoting connection (50) connecting the root (44.1) of the blade (44) and the hub (42) and having a pivot axis (A50) as well as at least one holding system (58) for holding the blade (44) connected to the hub (42). According to the invention, the holding system (58) is reinforced and comprises at least one main stop (62) secured to the hub (42) and configured to be housed at least partially in a transverse groove (60), provided at a surface secured to the root (44.1) of the blade (44), which extends over at least part of the circumference of the root (44.1). This solution limits the risks of blade or blade debris ejection. The invention also relates to an aircraft propulsion assembly comprising at least one such propeller. Figure 5

Description

Title of the invention: Propeller comprising at least one blade holding system comprising at least one transverse groove

[0001] The present application relates to a propeller comprising at least one blade holding system comprising at least one transverse groove as well as to an aircraft propulsion assembly comprising at least one such propeller.

[0002] According to an embodiment visible in [Fig.l], an aircraft 10 comprises a fuselage 12, wings 14 positioned on either side of the fuselage as well as propulsion assemblies 16 connected to the wings 14.

[0003] According to a configuration visible in [Fig.2], an electric type propulsion assembly 16 comprises at least one motor 18, a gearbox 20 and a propeller 22 connected to an output shaft 24 of the gearbox 20. The propeller 22 comprises a hub 26 which has an axis of rotation A26 and blades 28 which each have a first end 28.1, called the foot, connected to the hub 26.

[0004] For the remainder of the description, an axial direction corresponds to a direction parallel to the axis of rotation A26 of the hub 26. A radial direction is a direction perpendicular to the axis of rotation A26.

[0005] As illustrated in [Fig.3], for each blade 28, the hub 26 comprises a housing 30, delimited by a first lateral surface S30, having an axis of revolution coinciding with a radial direction. In addition, the root 28.1 of the blade 28 is configured to be housed in the housing 30 and has a second lateral surface S28.1 of revolution as well as an axis of revolution A28.

[0006] For a given blade, a longitudinal plane is a plane containing the axis of revolution A28 of the root 28.1 of the blade 28 and a transverse plane is a plane perpendicular to the axis of revolution A28.

[0007] According to one configuration, the blades 28 have variable pitch. For this purpose, the root 28.1 of each blade 28 is connected by a pivoting connection 32 to the hub 26, a holding system 34 making it possible to keep the blade 28 connected to the hub 26. This pivoting connection 32 comprises several bearings 32.1 interposed between the first and second lateral surfaces S30 and S28.1 of the hub 26 and the blade 28. The holding system 34 comprises first and second stops 34.1, 34.2 positioned on either side of a set of bearings 32.1, the first stop 34.1 being positioned between the axis of rotation A26 of the hub 26 and the set of bearings 32.1.

[0008] The first stop 34.1 is a fillet integral with the blade 28, located at the level of the second lateral surface S28.1 of the root 28.1 of the blade 28, bearing against one of the bearings 32.1. The second stop 34.2 is a nut positioned between the first and second lateral surfaces S30 and S28.1, bearing against one of the bearings 32.1, configured to screw onto a threaded section of the first lateral surface S30 of the housing 30 of the hub 26.

[0009] According to this embodiment, in the event of damage to the bearings 32.1 positioned between the first and second stops 34.1, 34.2 of the holding system 34 of the blade 28, the risks of ejection of this blade 28 are relatively high. Consequently, the parts of the aircraft likely to be impacted by the blade 28 or the debris of this blade 28 must be reinforced, which leads to an increase in the on-board mass of the aircraft.

[0010] The present invention aims to remedy all or part of the drawbacks of the prior art.

[0011] To this end, the invention relates to a propeller comprising a hub, blades each provided with a root and, for each blade, a connection system connecting the blade and the hub and comprising: a. at least one first lateral surface integral with the hub, b. at least one second lateral surface, integral with the foot of the blade, having a circumference, c. a pivoting connection having a pivot axis and at least one bearing interposed between the first and second lateral surfaces, d. at least one holding system to keep the blade connected to the hub.

[0012] According to the invention, the holding system comprises at least one transverse groove, located at the level of the second lateral surface, which extends over at least part of the circumference of the second lateral surface as well as at least one main stop, integral with the hub, configured to be housed at least partially in the transverse groove.

[0013] This solution makes it possible to limit the risks of blades or blade debris being projected. Thus, it is no longer necessary to reinforce the areas which were previously likely to be impacted by the blade or blade debris.

[0014] According to another characteristic, each transverse groove extends over the entire circumference of the second lateral surface.

[0015] According to another characteristic, the connection system comprises a sleeve, interposed between the foot of the blade and the bearing(s), having an external surface at the level of which the transverse groove(s) is / are provided.

[0016] According to another characteristic, the main stop comprises at least one finger secured to the hub, oriented perpendicular to the pivot axis, which extends between first and second ends, the first end being housed in the transverse groove. In addition, the hub comprises, for each finger, an orifice configured to partially accommodate the finger, the orifice having a section substantially equal to that of the finger and being oriented perpendicular to the pivot axis.

[0017] According to another characteristic, each finger is configured to occupy a first state in which the first end of the finger is housed in the transverse groove as well as a second state in which the second end of the finger is moved away from the blade and is no longer housed in the transverse groove.

[0018] According to another characteristic, the orifice is through, the second end of the finger being positioned outside the hub.

[0019] According to another characteristic, the finger comprises at least one threaded section configured to cooperate with a tapped section of the orifice.

[0020] According to another characteristic, the holding system comprises a lock nut configured to screw onto the finger and be in contact with the hub.

[0021] According to another characteristic, the holding system comprises a flexible link connecting the second end of the finger and the hub.

[0022] According to another characteristic, the finger and the transverse groove are positioned between the bearing(s) and an axis of rotation of the hub.

[0023] According to another characteristic, the holding system comprises at least one secondary stop chosen from a fillet, a shoulder, an elastic ring secured to the blade and / or a nut or an elastic ring secured to the hub.

[0024] The invention also relates to an aircraft propulsion assembly comprising at least one propeller according to one of the preceding characteristics.

[0025] Other characteristics and advantages will emerge from the description of the invention which follows, a description given by way of example only, with reference to the appended drawings, among which:

[0026] [Fig-1] is a side view of an aircraft,

[0027] [Fig.2] is a side view of a propulsion assembly of an aircraft,

[0028] [Fig.3] is a longitudinal section of a connecting system, connecting a blade and a hub of a propeller, illustrating an embodiment of the prior art,

[0029] [Fig.4] is a longitudinal section of a connecting system, connecting a blade and a hub of a propeller, illustrating an embodiment of the invention,

[0030] [Fig.5] is a longitudinal section of a part of a connecting system, connecting a blade and a hub of a propeller, illustrating another embodiment of the invention, and

[0031] [Fig.6] is a perspective view of the blade root visible in [Fig.5].

[0032] A propeller 40 comprises a hub 42 which has an axis of rotation as well as blades 44 which each have a foot 44.1 connected to the hub 42 by a connection system 46.

[0033] According to a non-limiting application, an aircraft comprises at least one propulsion assembly comprising at least one such propeller 40. This propulsion assembly may be electric or turboprop type

[0034] The blades 44 have variable pitch. To this end, for each blade 44, the connecting system 46 comprises the root 44.1 of the blade 44, a housing 48 secured to the hub 42 and configured to receive the root 44.1 of the blade 44 as well as a pivoting connection 50, connecting the root 44.1 of the blade 44 and the hub 42, which has a pivot axis A50.

[0035] According to one embodiment, the housing 48 of the hub 42 comprises a first lateral surface S48 having an axis of revolution coinciding with the pivot axis A50 when the blade 44 is connected to the hub 42. In addition, the root 44.1 of the blade 44 comprises a second lateral surface S52 having an axis of revolution coinciding with the pivot axis A50 when the blade 44 is connected to the hub 42.

[0036] The pivoting connection 50 comprises at least one bearing 54 interposed between the first and second lateral surfaces S48, S52 and configured to allow the root 44.1 of the blade 44 to pivot along the pivot axis A50 relative to the hub 42. According to one configuration, the pivoting connection 50 comprises several bearings 54, interposed between the first and second lateral surfaces S48, S52, offset relative to each other in a direction parallel to the pivot axis A50.

[0037] According to one configuration, each bearing 54 has an internal diameter substantially equal to the external diameter of the second lateral surface S52 of the foot 44.1 as well as an external diameter substantially equal to the internal diameter of the first surface S48.

[0038] Whatever the embodiment, the connection system 46 comprises at least one first lateral surface S48 secured to the hub 42, at least one second lateral surface S52 secured to the root 44.1 of the blade 44 as well as a pivoting connection 50 which has a pivot axis A50 and at least one bearing 54 interposed between the first and second lateral surfaces S48, S52. The first lateral surface S48 may be the lateral surface of the hub 42 or of any other part integral with the hub 42 and inserted between the latter and the bearing(s) 54. The second lateral surface S52 may be the lateral surface of the root 44.1 of the blade 44 or of any other part integral with the blade 44 and inserted between the latter and the bearing(s) 54. Thus, as illustrated in dotted lines in [Fig.5], the connecting system 46 may comprise a sleeve 56 inserted between the root 44.1 of the blade 44 and the bearing(s) 54, immobilized at least in rotation relative to the root 44.1 of the blade 44 and having an external surface which forms the second lateral surface S52, in contact with the bearing(s) 54 and oriented towards the first lateral surface S48 secured to the hub 42.

[0039] The connecting system 46 comprises at least one holding system 58 making it possible to keep the blade 44 connected to the hub 42. This holding system 58 comprises at least one transverse groove 60, located at the level of the second lateral surface S52, which extends over at least part of the circumference of the second lateral surface S52 as well as at least one main stop 62, integral with the hub 42, configured to be housed at least partially in the transverse groove 60 so as to immobilize the blade 44 relative to the hub 42 in the longitudinal direction (parallel to the pivot axis A50) and to allow the blade 44 to pivot relative to the hub 42 around the pivot axis A50.

[0040] According to one embodiment, each transverse groove 60 extends over the entire circumference of the second lateral surface S52.

[0041] Each transverse groove 60 comprises a first annular edge 60.1 positioned in a first transverse plane perpendicular to the pivot axis A50, a second annular edge 60.2 positioned in a second transverse plane perpendicular to the pivot axis A50 as well as a bottom 60.3, connecting the first and second annular edges 60.1, 60.2, cylindrical and coaxial with the pivot axis A50. Each transverse groove 60 has a given width (dimension taken in the longitudinal direction between the first and second annular edges 60.1, 60.2).

[0042] According to one embodiment, the transverse groove 60 is provided at the level of the outer surface of the sleeve 56 forming the second lateral surface S52. Thus, the blade 44 can be made of composite material and the sleeve 56 of another material, for example metallic.

[0043] According to one arrangement, the holding system 58 comprises first and second transverse grooves 60, 60' positioned on either side of the bearing(s) 54, the first transverse groove 60 being offset towards the axis of rotation of the hub 42 relative to the bearing(s) 54.

[0044] According to one embodiment, the main stop 62 comprises at least one finger 64, integral with the hub 42 and oriented perpendicular to the pivot axis A50, which extends between first and second ends 64.1, 64.2, the first end 64.1 being housed in the transverse groove 60, between the first and second annular edges 60.1, 60.2. The finger 64 (more particularly its first end 64.1) has a section equal to or very slightly less than the width of the transverse groove 60 in which the first end 64.1 is housed.

[0045] According to one configuration, each finger 64 is configured to occupy a first state in which the first end 64.1 of the finger 64 is housed in the transverse groove 60 as well as a second state in which the second end 64.1 of the finger 64 is spaced from the blade 44 and is no longer housed in the transverse groove 60. In this second state, the blade 44 can be dismantled.

[0046] According to one configuration, the finger 64 is cylindrical. In addition, the hub 42 comprises, for each finger 64, an orifice 66 configured to partially house the finger 64, the orifice 66 having a section substantially equal to that of the finger and being oriented perpendicular to the pivot axis A50.

[0047] According to one arrangement, the orifice 66 is a through orifice. In addition, the second end 64.2 of the finger 64 is positioned outside the hub 42 so as to be easily accessible for mounting or dismounting the finger 64.

[0048] According to one embodiment, the finger 64 comprises at least one threaded section configured to cooperate with a tapped section of the orifice 66. To prevent the finger 64 from unscrewing, the holding system 58 comprises a locknut 68 configured to screw onto the finger 64 and be in contact with the hub 42. Thus, it is possible to position the finger 64 in the first or second state by screwing or unscrewing it.

[0049] According to one configuration, the holding system 58 comprises a flexible link 70 connecting the finger 64, more particularly its second end 64.2, and the hub 42, more particularly a screw 72 screwed into a tapped hole provided in the hub 42. This configuration makes it possible to keep the finger 64 connected to the hub 42 when it is dismantled.

[0050] According to one arrangement, the main stop 62 comprises a single finger 64. As a variant, the main stop 62 comprises several fingers 64, cooperating with the same transverse groove 60, distributed around the pivot axis A50.

[0051] According to a configuration visible in [Fig.4], the finger 64 and the transverse groove 60 are further apart than the bearings 54 of the axis of rotation of the hub 42.

[0052] According to another configuration visible in [Fig.5], the finger 64 and the transverse groove 60 are positioned between the bearings 54 and the axis of rotation of the hub 42. For this purpose, the root 44.1 of the blade 44 comprises an extension which extends beyond the bearings 54 in the direction of the axis of rotation of the hub 42.

[0053] Of course, the invention is not limited to these embodiments for the main stop 62. Whatever the embodiment, the main stop 62 is integral with the hub 42 and has a part housed in the transverse groove 60 to immobilize the blade 44 relative to the hub 42 in the longitudinal direction (parallel to the pivot axis A50). The holding system 58 makes it possible to limit the risks of projection of blades or blade debris. Thus, it is no longer necessary to reinforce the areas which were previously likely to be impacted by the blade or blade debris.

[0054] The holding system 58 may comprise at least one secondary stop 74, 74', 74'' to limit the movements of the blade 44 relative to the hub 42 in the longitudinal direction (parallel to the pivot axis A50), chosen from a fillet, a shoulder, an elastic ring secured to the blade 44 and / or a nut or an elastic ring secured to the hub 42.

[0055] According to an embodiment visible in [Fig.5], the holding system 58 comprises a first secondary stop 74 in the form of a fillet or a shoulder provided at the second lateral surface S52 and / or a second secondary stop 74' in the form of an elastic ring partially housed in a transverse groove 60' provided at the second lateral surface S52, the first and second secondary stops 74, 74' being positioned on either side of the bearings 54.

[0056] According to another embodiment visible in [Fig. 3], the holding system 58 comprises a first secondary stop 74 in the form of a fillet or a shoulder provided at the level of the second lateral surface S52 and / or a second secondary stop 74” in the form of a nut configured to be screwed onto a threaded section of the first lateral surface S48 of the housing 48, the first and second secondary stops 74, 74” being positioned on either side of the bearings 54.

[0057] Of course, the invention is not limited to these embodiments for the secondary stops 74, 74', 74”. These secondary stops make it possible to reinforce the capacities of the holding system 58 to hold the blade 44 connected to the hub 42.

[0058] According to a first configuration, the transverse groove 60 and the main stop 62 are adjusted together (no play in the longitudinal direction is present between the transverse groove 60 and the main stop 62). In this case, the transverse groove 60 and the main stop 62 contribute to maintaining the blade 44 in normal configuration by offering an additional solution for transferring the forces from the blade 44 to the hub 42 in addition to a prior art maintaining system comprising at least one element from a bearing, a stop or a nut for example.

[0059] According to a second configuration, the holding system 58 has a clearance in the longitudinal direction between the transverse groove 60 and the main stop 62. In this case, the transverse groove 60 and the main stop 62 offer a standby solution for transferring the forces from the blade 44 to the hub 42. This standby solution will then be active in the event of breakage of the holding system of the prior art comprising at least one element among a bearing, a stop or a nut for example.

Claims

Claims

1. Propeller comprising a hub (42), blades (44) each provided with a root (44.1) and, for each blade (44), a connecting system (46) connecting the blade (44) and the hub (42) and comprising: a. at least one first lateral surface (S48) integral with the hub (42), b. at least one second lateral surface (S52), integral with the root (44.1) of the blade (44), having a circumference, c. a pivoting connection (50) having a pivot axis (A50) and at least one bearing (54) interposed between the first and second lateral surfaces (S48, S52), d.at least one holding system (58) for holding the blade (44) connected to the hub (42), characterized in that the holding system (58) comprises at least one transverse groove (60), located at the level of the second lateral surface (S52), which extends over at least part of the circumference of the second lateral surface (S52) as well as at least one main stop (62), integral with the hub (42), configured to be housed at least partially in the transverse groove (60).

2. Propeller according to claim 1, characterized in that each transverse groove (60) extends over the entire circumference of the second lateral surface (S52).

3. Propeller according to one of the preceding claims, characterized in that the connecting system (46) comprises a sleeve (56), interposed between the root (44.1) of the blade (44) and the bearing(s) (54), having an external surface at the level of which the transverse groove(s) (60) is (are) provided.

4. Propeller according to one of the preceding claims, characterized in that the main stop (62) comprises at least one finger (64), integral with the hub (42) and oriented perpendicular to the pivot axis (A50), which extends between first and second ends (64.1, 64.2), the first end (64.1) being housed in the transverse groove (60), and in that the hub (42) comprises, for each finger (64), an orifice (66) configured to partially house the finger (64), the orifice (66) having a section substantially equal to that of the finger (64) and being oriented perpendicular to the pivot axis (A50).

5. Propeller according to the preceding claim, characterized in that each finger (64) is configured to occupy a first state in which the first end (64.1) of the finger (64) is housed in the transverse groove (60) as well as a second state in which the second end (64.1) of the finger (64) is spaced from the blade (44) and is no longer housed in the transverse groove (60).

6. Propeller according to one of claims 4 to 5, characterized in that the orifice (66) is through, the second end (64.2) of the finger (64) being positioned outside the hub (42).

7. Propeller according to the preceding claim, characterized in that the finger (64) comprises at least one threaded section configured to cooperate with a tapped section of the orifice (66).

8. Propeller according to the preceding claim, characterized in that the holding system (58) comprises a lock nut (68) configured to screw onto the finger (64) and be in contact with the hub (42).

9. Propeller according to one of claims 6 to 8, characterized in that the holding system (58) comprises a flexible link (70) connecting the second end (64.2) of the finger (64) and the hub (42).

10. Propeller according to one of claims 4 to 9, characterized in that the finger (64) and the transverse groove (60) are positioned between the bearing(s) (54) and an axis of rotation of the hub (42).

11. Propeller according to one of the preceding claims, characterized in that the holding system (58) comprises at least one secondary stop (74, 74', 74”) chosen from a fillet, a shoulder, an elastic ring secured to the blade (44) and / or a nut or an elastic ring secured to the hub (42).

12. Aircraft propulsion assembly comprising at least one propeller according to one of the preceding claims.

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