Variable-pitch toroidal propeller, flying vehicle comprising at least one such propeller

Abstract

Variable-pitch toroidal propeller, flying vehicle comprising at least one such propeller. The invention relates to a toroidal propeller (30) comprising at least one movable part (40) of which at least one radial edge (40.3, 40.4) forms at least a portion of the leading or trailing edge (38.3, 38.4) of a radial blade section (38) of the toroidal propeller (30). This movable part (40) is configured to occupy a first state in which the radial edge (40.3, 40.4) of the movable part (40) occupies a first position and the radial blade section (38) has a first pitch angle, and a second state in which the radial edge (40.3, 40.4) occupies a second position, different from the first position, and the radial blade section (38) has a second pitch angle different from the first pitch angle. Such a helix offers the advantages of both a toroidal helix and a variable-pitch helix according to the prior art. Figure 4

Description

Title of the invention: Variable pitch toroidal propeller, flying vehicle comprising at least one such propeller

[0001] The present application relates to a propeller for a flying vehicle, more particularly to a variable pitch toroidal propeller, as well as to a flying vehicle comprising at least one such propeller.

[0002] According to a first embodiment visible in [Fig.l], a propeller 10 comprises a hub 12 configured to pivot about an axis of rotation A12 as well as several blades 14 which each extend between first and second ends 14.1, 14.2, the first end 14.1 of each blade 14 being connected to the hub 12, the second ends 14.2 of the blades 14 being spaced apart from each other. Each blade 14 extends in a radial direction substantially perpendicular to the axis of rotation A12 and comprises leading and trailing edges. Each blade 14 has a pitch angle corresponding, in a plane approximately perpendicular to the radial direction, to the angle formed between a plane perpendicular to the axis of rotation A12 and the straight line passing through the leading and trailing edges.

[0003] According to one configuration, a propeller may have variable pitch. According to this configuration, each blade 14 is connected to the hub 12 by a pivoting connection 16 allowing the blade 14 to pivot about a pivot axis A16 substantially perpendicular to the rotation axis A12 in order to modify the pitch angle.

[0004] A variable pitch propeller 10 makes it possible to optimize its efficiency according to its rotation speed. However, it has the disadvantages of being relatively noisy and generating vortices at the tip of the blade.

[0005] According to a second embodiment visible in [Fig.2], a toroidal propeller 20 comprises a hub 22 configured to pivot about an axis of rotation A22 as well as blades 24 which each extend between first and second ends 24.1, 24.2, the first end 24.1 of each blade 24 being connected to the hub 22. Unlike the first embodiment, the second end 24.2 of each blade 24 is not free but connected to another blade.

[0006] These toroidal propellers reduce noise pollution, improve the efficiency of the propeller and prevent the appearance of vortices at the tip of the blade.

[0007] The second end 24.2 of each blade 24 being connected to another blade 24, it is not possible to modify the pitch angle by pivoting the blade 24 at the level of its junction zone with the hub 22, as in the case of the first embodiment.

[0008] The present invention aims to remedy all or part of the drawbacks of the art prior.

[0009] To this end, the invention relates to a toroidal propeller comprising a hub configured to pivot about an axis of rotation as well as at least one radial blade section which extends in a radial direction and has leading and trailing edges.

[0010] According to the invention, the toroidal propeller comprises at least one movable part, positioned at the radial blade section, comprising at least one radial edge which forms at least a part of the leading or trailing edge of the radial blade section, the movable part being configured to occupy at least first and second states; the radial edge of the movable part occupying a first position and the radial blade section having a first pitch angle in the first state, the radial edge of the movable part occupying a second position, different from the first position, and the radial blade section having a second pitch angle different from the first pitch angle in the second state.

[0011] This solution makes it possible to obtain a variable pitch toroidal propeller which combines the advantages of a toroidal propeller and a variable pitch propeller of the prior art.

[0012] According to another characteristic, the mobile part is configured to occupy a multitude of states between first and second extreme states for which the radial blade section has respectively minimum and maximum pitch angles.

[0013] According to another characteristic, the movable part extends between first and second radial edges respectively forming at least part of the leading and trailing edges of the radial blade section.

[0014] Alternatively, one of the first and second radial edges is spaced from the leading or trailing edge of the radial blade section.

[0015] According to another characteristic, the movable part deforms to pass from one state to the other. In this case, the movable part may comprise first and second opposite walls which each extend between first and second radial edges. In addition, the first and second walls are configured to deform in opposite directions to pass from one state to the other.

[0016] According to another characteristic, the movable part is configured to pivot about a first pivot axis substantially parallel to the radial direction. In this case, for each movable part of a radial blade section, the toroidal propeller may comprise: a. a pivot shaft having a first pivot axis and extending between first and second ends, the first end being connected to the hub, b. a pivoting connection, connecting the movable part and the pivot shaft, allowing the movable part to pivot about the first pivot axis.

[0017] According to another characteristic, each movable part extending between first and second radial edges, the first pivot axis is positioned substantially equidistant from the first and second radial edges.

[0018] According to another characteristic, the toroidal propeller comprises several radial blade sections distributed around the hub as well as a movable part for each radial blade section.

[0019] According to another characteristic, the moving parts of the toroidal helix move or deform in a synchronized manner.

[0020] According to another characteristic, the toroidal propeller comprises a control system configured to control all the moving parts.

[0021] According to another characteristic, the control system comprises a control ring movable in a direction parallel to the axis of rotation and positioned around the axis of rotation as well as, for each movable part, a control link connecting the control ring and the corresponding movable part.

[0022] According to another characteristic, each control link comprises: a. a first rigid rod, oriented parallel to the axis of rotation and fixed relative to the control ring, which extends between a first end connected to the control ring and a second end, b. a second rigid rod which extends between a first end connected to the movable part and a second end connected to the second end of the first rigid rod, c. a ball joint connecting the second ends of the first and second rigid rods, d. a pivoting connection, connecting the first end of the second rigid rod and the movable part, having a second pivot axis positioned in a plane perpendicular to the first pivot axis.

[0023] The invention also relates to a flying vehicle comprising at least one toroidal propeller according to one of the preceding characteristics.

[0024] 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:

[0025] [Fig. 1] is a perspective view of a propeller illustrating a first embodiment of the prior art,

[0026] [Fig.2] is a perspective view of a propeller illustrating a second embodiment of the prior art,

[0027] [Fig.3] is a rear view of a propeller illustrating an embodiment of the invention,

[0028] [Fig.4] is a front view of a propeller illustrating another embodiment of the invention,

[0029] [Fig.5] is a side view of the propeller visible in [Fig.4],

[0030] [Fig.6] is a perspective view from a first viewing angle of the visible propeller on [Fig.4],

[0031] [Fig.7] is a perspective view from a second viewing angle of the visible propeller on [Fig.4],

[0032] [Fig.8] is a perspective view of a central part of the propeller visible on the [Fig.4],

[0033] [Fig.9] is a rear view of a peripheral fixed part of the propeller visible on the [Fig.4],

[0034] [Fig. 10] is a cross-section of a blade in a first undeformed state on part (A) and in a second deformed state on part (B) illustrating an embodiment of the invention.

[0035] According to an embodiment visible in Figures 4 to 9, a propeller 30 comprises a hub 32 configured to pivot around an axis of rotation A32 as well as several blades 34 positioned around the axis of rotation A32.

[0036] According to one application, a flying vehicle comprises at least one propeller 30.

[0037] For the remainder of the description, a longitudinal direction is a direction parallel to the axis of rotation A32. A radial direction is a direction perpendicular to the axis of rotation A32. For each blade 34, a transverse plane is a plane perpendicular to the radial direction of the blade 34. Finally, the terms front and rear refer to the direction of flow of the air propelled by the propeller 30, which goes from front to rear.

[0038] The propeller 30 is a toroidal propeller. Each blade 34 comprises a first end 34.1 connected to the hub 32 as well as a second end 34.2, connected directly or indirectly, to another blade 34 of the propeller 30.

[0039] According to one configuration, for each blade, the second end 34.2 of a first blade 34 is directly connected to a second blade at a junction zone spaced from the first end 34.1 of the second blade. According to this configuration, each blade comprises a first portion which extends between the first end 34.1 and the junction zone with a first blade, oriented in a radial direction, as well as a second curved portion, which extends between the junction zone and the second end 34.2, connecting the blade to a second blade.

[0040] According to another configuration visible in Figures 4 to 9, each blade 34 extends between first and second ends 34.1, 34.2 oriented in a radial direction. In addition, the propeller 30 comprises curved propeller portions 36 connecting the second ends 34.2 of the blades 34 two by two.

[0041] According to one embodiment, at least one of the blades 34 of the toroidal propeller 30 comprises at least one radial blade section 38 which extends between a first section transverse 38.1 connected to the hub 32 and a second transverse section 38.2, spaced from the hub 32, located at the second end 34.2 of the blade 34 or the junction zone with another blade. For a given blade 34, the first and second transverse sections 38.1, 38.2 are substantially perpendicular to the radial direction of the blade 34. This radial blade section 38 has leading and trailing edges 38.3, 38.4 connecting the first and second transverse sections 38.1, 38.2.

[0042] The toroidal propeller 30 comprises at least one movable part 40, positioned at one of the radial blade sections 38, which comprises at least one radial edge 40.3, 40.4 forming at least a part of the leading or trailing edge 38.3, 38.4 of the radial blade section 38.

[0043] According to one embodiment, the movable part 40 is delimited by at least a first end section 40.1 substantially perpendicular to the radial direction of the radial blade section 38 and oriented towards the first cross-section 38.1, at least a second end section 40.2 substantially perpendicular to the radial direction and oriented towards the second cross-section 38.2, a first radial edge 40.3 connecting the first and second end sections 40.1, 40.2 and oriented approximately in the radial direction as well as a second radial edge 40.4 connecting the first and second end sections 40.1, 40.2 and oriented approximately in the radial direction, at least one radial edge among the first and second radial edges 40.3, 40.4 forming at least a portion of the leading or trailing edge 38.3, 38.4 of the radial blade section 38.

[0044] Each movable part 40 comprises a first wall S40, oriented towards the front of the propeller 30, which extends from the first radial edge 40.3 to the second radial edge 40.4 as well as a second wall S40', opposite the first wall S40 and oriented towards the rear of the propeller 30, which extends from the first radial edge 40.3 to the second radial edge 40.4, as illustrated in [Fig. 10].

[0045] According to an arrangement visible in [Fig. 3], the first and second end sections 40.1, 40.2 of the movable part 40 are respectively merged with the first and second transverse sections 38.1, 38.2 of the radial blade section 38. According to this arrangement, the movable part 40 extends over the entire length of the radial blade section 38, the length corresponding to the dimension taken in the radial direction.

[0046] According to another arrangement visible in Figures 4 to 9, at least one of the first and second end sections 40.1, 40.2 of the movable part 40 is spaced from the first or second cross section 38.1, 38.2. According to one embodiment, the first and second end sections 40.1, 40.2 of the movable part 40 are spaced from the first and second cross sections 38.1, 38.2.

[0047] According to one configuration, the movable part 40 extends over the entire width of the radial blade section 38. According to this configuration, the first and second radial edges 40.3, 40.4 of the movable part 40 respectively form at least part of the leading and trailing edges 38.3, 38.4 of the radial blade section 38.

[0048] According to another configuration, the movable part 40 does not extend over the entire width of the radial blade section 38. According to this configuration, the first radial edge 40.3 forms at least a portion of the leading edge 38.3 of the radial blade section 38 or the second radial edge 40.4 forms at least a portion of the trailing edge 38.4 of the radial blade section 38. Thus, one of the first and second radial edges 40.3, 40.4 is spaced from the leading or trailing edge 38.3, 38.4 of the radial blade section 38.

[0049] The movable part 40 is configured to occupy at least first and second states, a first state in which at least one radial edge 40.3, 40.4 of the movable part 40 forming at least in part the leading or trailing edges 38.3, 38.4 of the radial blade section 38 occupies a first position and the radial blade section 38 has a first pitch angle as well as a second state in which said radial edge 40.3, 40.4 of the movable part 40 occupies a second position, different from the first position, and the radial blade section 38 has a second pitch angle different from the first pitch angle.

[0050] A pitch angle corresponds, in a transverse plane situated between the first and second end sections 40.1, 40.2 of the movable part 40, to an angle formed between a straight line passing through the leading and trailing edges 38.1, 38.2 of the radial blade section 38 and a plane perpendicular to the axis of rotation A32.

[0051] Being able to modify the pitch angle of the radial blade section 38 makes it possible to obtain a toroidal propeller 30 with variable pitch which has the advantages of a toroidal propeller (reduction of noise pollution and absence of vortex at the tip of the blade) and those of a variable pitch propeller (adaptation of the geometry of the blades in particular as a function of the rotation speed of the propeller to optimize its efficiency).

[0052] According to one embodiment, the movable part 40 is configured to occupy a multitude of states between first and second extreme states for which the radial blade section 38 has respectively minimum and maximum pitch angles. According to one arrangement, the pitch angles vary progressively between the minimum and maximum pitch angles during a progressive transition from the first extreme state to the second extreme state or vice versa.

[0053] According to one embodiment, the toroidal propeller 30 comprises several radial blade sections 38 distributed around the hub 32 as well as a movable part 40 for each radial blade section 38.

[0054] According to a first configuration visible in [Fig. 10], the mobile part 40 deforms to pass from one state to the other. According to one arrangement, the first and second walls S40, S40' are configured to deform, elastically, in first and second directions corresponding respectively to a stretching and a contraction between the first and second radial edges 40.3, 40.4, the first and second walls S40, S40' deforming in opposite directions. Thus, when the first wall S40 stretches between the first and second radial edges 40.3, 40.4, the second wall S40' contracts between the first and second radial edges 40.3, 40.4. Conversely, when the first wall S40 contracts between the first and second radial edges 40.3, 40.4, the second wall S40' stretches between the first and second radial edges 40.3, 40.4.

[0055] According to this first configuration, when the mobile part 40 occupies a first state as illustrated in part (A) of [Fig. 10], the radial blade section 38 has a first setting angle A1.

[0056] When the mobile part 40 occupies a second state, after a deformation of the first wall S40 in a first direction (corresponding to a stretching) and a deformation of the second wall S40' in a second direction opposite to the first direction (corresponding to a contraction) as illustrated in part (B) of [Fig. 10], the radial blade section 38 has a second pitch angle A2 different from the first pitch angle A1.

[0057] According to a second configuration visible in Figures 4 to 9, the movable part 40 is configured to pivot around a first pivot axis A42 oriented in the radial direction of the radial blade section 38 at which the movable part 40 is positioned.

[0058] According to an embodiment visible in [Fig.8], for each mobile part 40 of a radial blade section 38, the propeller 30 comprises: a. a pivot shaft 42 which has a first pivot axis A42 and extends, in the radial direction of the radial blade section 38, between first and second ends 42.1, 42.2, the first end 42.1 being connected to the hub 32, b. a pivoting connection connecting the movable part 40 and the pivot shaft 42 allowing the movable part 40 to pivot about the first pivot axis A42.

[0059] According to one arrangement, the first pivot axis A42 is positioned substantially equidistant from the first and second radial edges 40.3, 40.4. Alternatively, the first pivot axis A42 may be positioned closer to the first radial edge 40.3 than to the second radial edge 40.4 or vice versa or be positioned at the first or second radial edge 40.3, 40.4.

[0060] According to one configuration, for each blade 34 comprising a movable part 40, the latter is adjacent to the hub 32 or slightly spaced from the latter.

[0061] Of course, the invention is not limited to the first and second configurations for making the movable part 40 mobile, at least one radial edge 40.3, 40.4 of which forms at least a part of the leading or trailing edge 38.3, 38.4 of the radial blade section 38.

[0062] According to one embodiment, each radial blade section 38 comprises at least one movable part 40. Of course, the invention is not limited to this embodiment. According to one configuration, at least one radial blade section 38 of the toroidal propeller 30 comprises at least one movable part 40 and at least one radial blade section 38 of the toroidal propeller 30 does not comprise any movable part 40.

[0063] According to one embodiment, the toroidal helix 30 comprises, in addition to the movable part(s) 40, at least one fixed part 44 (visible in [Fig.9]), the movable part(s) 40 and the fixed part(s) 44 having complementary shapes so as to form the entire toroidal helix 30.

[0064] According to one embodiment, the fixed part 44 comprises several sections connected to each other. The fixed part 44 can optionally deform elastically in at least one zone to follow the movements of at least one mobile part 40.

[0065] According to one configuration, the fixed part 44 is connected to the hub 32 and comprises, for each mobile part 40, a recess 46 (visible in [Fig.9]) to at least partially house the mobile part 40.

[0066] According to another configuration, at least one movable part 40 separates the hub 32 and the fixed part 44 or two portions of the fixed part 44. According to this configuration, the toroidal helix 30 comprises at least one connecting element which extends on either side of the movable part 40 and has a first end connected to the hub 32 (or a first portion of the fixed part 44) as well as a second end connected to the fixed part (or a second portion of the fixed part). By way of example, the connecting element also provides the function of pivot shaft 42.

[0067] According to a first variant, the moving parts 40 of the toroidal helix 30 move or deform in a synchronized manner. According to another variant, the moving parts 40 of the toroidal helix 30 move or deform independently of each other.

[0068] According to a first mode of operation, the moving parts 40 of the toroidal propeller 30 are self-adaptive and move or deform autonomously and automatically. According to this first mode of operation, the moving parts 40 of the toroidal propeller 30 move or deform as a function of at least one external constraint such as the difference between the pressures of the air flow circulating around the moving part 40 applied to the first and second walls S40, S40' of the moving part 40.

[0069] According to a second mode of operation, the moving parts 40 of the propeller toroidal propeller 30 are driven and move or deform in a controlled manner. For this purpose, the toroidal propeller 30 comprises at least one control system 48 for controlling the movements or deformations of at least one moving part 40.

[0070] According to one configuration, the toroidal propeller 30 comprises a control system 48 for each moving part 40.

[0071] According to another configuration, the toroidal helix 30 comprises a control system 48 configured to control all the movable parts 40. According to this configuration, the control system 48 comprises a control disc or ring 50 movable in the longitudinal direction and positioned around the axis of rotation A32 as well as, for each movable part 40, a control link 52 connecting the control disc or ring 50 and the corresponding movable part 40. According to an arrangement visible in FIGS. 5 and 8, each control link 52 comprises: a. a first rigid rod 54, oriented parallel to the axis of rotation A32 and fixed relative to the control disc or ring 50, which extends between a first end 54.1 connected to the control disc or ring 50 and a second end 54.2, b. a second rigid rod 56 which extends between a first end 56.1 connected to the movable part 40 and a second end 56.2 connected to the second end 54.2 of the first rigid rod 54, c. a ball joint 58 connecting the second ends 54.2, 56.2 of the first and second rigid rods 54, 56, d. a pivoting connection 60 which connects the first end 56.1 of the second rigid rod 56 and the movable part 40 and has a second pivot axis A60 positioned in a plane perpendicular to the first pivot axis A42.

[0072] In addition, the control system 48 may comprise a guide ring 62 positioned around the axis of rotation A32, between the disc or the control ring 50 and the blades 34, which has, for each first rigid rod 54, a through-orifice 62.1 configured to guide said first rigid rod 54.

[0073] Of course, the invention is not limited to this embodiment for the control system 48.

Claims

Claims

1. Toroidal propeller (30) comprising a hub (32) configured to pivot about an axis of rotation (A32) and at least one radial blade section (38) which extends in a radial direction and has leading and trailing edges (38.3, 38.4), characterized in that the toroidal propeller (30) comprises at least one movable part (40), positioned at the radial blade section (38), comprising at least one radial edge (40.3, 40.4) which forms at least a part of the leading or trailing edge (38.3, 38.4) of the radial blade section (38), the movable part (40) being configured to occupy at least first and second states, the radial edge (40.3, 40.4) of the movable part (40) occupying a first position and the radial blade section (38) having a first angle of wedging in the first state, the radial edge (40.3, 40.4) of the movable part (40) occupying a second position, different from the first position, and the radial blade section (38) having a second pitch angle different from the first pitch angle in the second state.

2. Toroidal propeller (30) according to claim 1, characterized in that the movable part (40) is configured to occupy a multitude of states between first and second extreme states for which the radial blade section (38) has respectively minimum and maximum pitch angles.

3. Toroidal propeller (30) according to one of claims 1 to 2, characterized in that the movable part (40) extends between first and second radial edges (40.3, 40.4) respectively forming at least part of the leading and trailing edges (38.3, 38.4) of the radial blade section (38).

4. Toroidal propeller (30) according to one of claims 1 to 2, characterized in that the movable part (40) extends between first and second radial edges (40.3, 40.4), one of the first and second radial edges (40.3, 40.4) being spaced from the leading or trailing edge (38.3, 38.4) of the radial blade section (38).

5. Toroidal helix (30) according to one of the preceding claims, characterized in that the movable part (40) deforms to pass from one state to the other.

6. Toroidal helix (30) according to the preceding claim, characterized in that the movable part (40) comprises first and second walls (S40, S40') opposite each extending between first and second radial edges (40.3, 40.4) and in that the first and second walls (S40, S40') are configured to deform in opposite directions in order to pass from one state to the other.

7. Toroidal helix (30) according to one of claims 1 to 4, characterized in that the movable part (40) is configured to pivot about a first pivot axis (A42) substantially parallel to the radial direction.

8. Toroidal propeller according to the preceding claim, characterized in that, for each movable part (40) of a radial blade section (38), the toroidal propeller (30) comprises: a. a pivot shaft (42) which has a first pivot axis (A42) and extends between first and second ends (42.1, 42.2), the first end (42.1) being connected to the hub (32), b. a pivoting connection, connecting the movable part (40) and the pivot shaft (42), which allows the movable part (40) to pivot about the first pivot axis (A42).

9. Toroidal helix according to the preceding claim, characterized in that, each movable part (40) extending between first and second radial edges (40.3, 40.4), the first pivot axis (A42) is positioned substantially equidistant from the first and second radial edges (40.3, 40.4).

10. Toroidal propeller (30) according to one of the preceding claims, characterized in that the toroidal propeller (30) comprises several radial blade sections (38) distributed around the hub (32) as well as a movable part (40) for each radial blade section (38).

11. Toroidal helix (30) according to the preceding claim, characterized in that the movable parts (40) of the toroidal helix (30) move or deform in a synchronized manner.

12. Toroidal helix according to one of claims 10 to 11, characterized in that the toroidal helix (30) comprises a control system (48) configured to control all the moving parts (40).

13. Toroidal propeller according to the preceding claim, characterized in that the control system (48) comprises a control disc or ring (50) movable in a direction parallel to the axis of rotation (A32) and positioned around the axis of rotation (A32) as well as, for each moving part (40), a control link (52) connecting the control disc or ring (50) and the corresponding moving part (40).

14. Toroidal helix according to the preceding claim, characterized in that each control link (52) comprises: a. a first rigid rod (54), oriented parallel to the axis of rotation (A32) and fixed relative to the control disc or ring (50), which extends between a first end (54.1) connected to the control disc or ring (50) and a second end (54.2), b. a second rigid rod (56) which extends between a first end (56.1) connected to the movable part (40) and a second end (56.2) connected to the second end (54.2) of the first rigid rod (54), c. a ball joint (58) connecting the second ends (54.2, 56.2) of the first and second rigid rods (54, 56), d. a pivoting connection (60), connecting the first end (56.1) of the second rigid rod (56) and the movable part (40), which has a second pivot axis (A60) positioned in a plane perpendicular to the first pivot axis (A42).

15. Flying vehicle comprising at least one toroidal propeller according to one of the preceding claims.

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