Multicopter, and robot device for a multicopter

Abstract

The invention relates to a multicopter comprising a plurality of rotor devices (14), a rotor device (14) comprising at least one rotor blade (20) which is rotatable about a rotor blade axis (22). It is proposed that the rotor device (14) further comprises: a first section (24) rotatably driven about an axis of rotation (16), a second section (26) which is movable relative to the first section (24) about an axis running parallel to the axis of rotation (16) and to which the rotor blade (20) is attached or which comprises the rotor blade (20), wherein a relative position of the second section (26) in relation to the first section (24) depends on a torque (M) with which the first section (24) is driven, and a mechanical coupling (34) which couples the relative position of the first section (24) relative to the second section (26) to a rotational position of the rotor blade (20) about the rotor blade axis (22).

Description

[0001] Title : Multicopter , as well as rotor device for a

[0002] Multicopter

[0003] Description

[0004] The invention relates to a multicopter and a rotor device for a multicopter according to the preambles of the independent claims.

[0005] Drones in the form of multicopters are known from the market, usually with four rotor devices. Each rotor device comprises a rotor shaft driven by an electric motor, a rotor head coupled to the rotor shaft and at least two rotor blades attached to the rotor head. The known multicopters are normally controlled by changing the speed of the rotor devices, since this can be achieved with few moving parts. In such a

[0006] In this case, the propellers can be rigid; only a certain amount of electronics is required for motor control. Wu, Xionan, 2018, Design and Development of variable Pitch Quadcopter for long Endurance Flight, Master Thesis, Oklahoma State University, describes the use of actuators in a multicopter to actively control the position of the rotor blades around a rotor blade axis, i.e., to control the angle of attack of the rotor blades. Variable-pitch propellers are also known, for example, from EP 0 589 338 A1 and from US 1,864,045 A.

[0007] The object of the present invention is to create a multicopter which produces little noise during operation, can be controlled dynamically, is easy to manufacture and is very efficient.

[0008] This object is achieved by a multicopter and by a rotor device for a multicopter having the features of the independent claims. Advantageous further developments are mentioned in the dependent claims.

[0009] The invention solves the above problem by means of a mechanical automatic mechanism for coupling the drive torque with the blade angle of attack in rotor devices of multicopters, i.e. a blade angle adjustment or an adjustment of the rotational position or the angle of attack of the rotor blades about the rotor blade axis, which does not require active actuators and functions automatically and solely on the basis of the torque applied to the rotor shaft or a change in torque. This makes it possible to equip the multicopter according to the invention with rotor devices that have a comparatively large diameter and thus a comparatively large rotor circular area. This reduces the power required to generate a certain thrust, thus improving the efficiency of the rotor devices. Thanks to the invention, a longer flight time can be achieved with the same battery capacity.Furthermore, noise emissions decrease with a larger rotor diameter and the associated lower speeds. The multicopter according to the invention is therefore particularly quiet.

[0010] Specifically, the aforementioned advantages are realized by a multicopter comprising a plurality of rotor devices. The term “multicopter” is by no means restricted to unmanned aircraft, but also includes manned aircraft, such as E-VTOL aircraft. Typically, such a multicopter comprises two or more rotor devices. A rotor device comprises, for example, a rotor shaft driven by an electric motor, which is aligned more or less vertically in the normal operating position of the multicopter. The rotor device can also include a rotor head coupled to the rotor shaft. Typically, the rotor head is arranged at an upper end of the rotor shaft in the normal operating position of the multicopter.

[0011] The rotor device further comprises at least one rotor blade which extends radially outwards. The rotor blade is rotatable about a rotor blade axis, as a result of which the angle of attack of the rotor blade can be varied. The rotor blade axis can be understood as a longitudinal axis of the rotor blade, at least in that region in which the rotor blade is fastened ("root"). The rotor blade itself can extend essentially straight radially outwards, so that its longitudinal axis is also straight. However, slightly sickle-shaped rotor blades are also known, the projecting end of which is slightly curved.

[0012] In the multicopter according to the invention, the rotor device has a first section which is driven to rotate about an axis of rotation, and a second section which is movable relative to the first section about an axis which runs parallel to the axis of rotation. Typically, the two sections are arranged coaxially to one another, but other designs are also conceivable. The rotor blades are fastened to the second movable section, which is therefore rotatable relative to the first section to at least a certain extent. A relative position of the second section to the first section depends on a torque with which the first section is driven and set in rotation.

[0013] However, the two sections are not completely independent of each other, because the rotor device comprises a mechanical coupling that couples the relative position of the first section relative to the second section with a rotational position of the rotor blade about its rotor blade axis. Said mechanical coupling thus couples an input variable (relative position of the sections) with an output variable (rotational position of the rotor blade). As soon as the relative position of one section to the other changes, the rotational position of the rotor blade about the rotor blade axis, i.e., the angle of attack of the rotor blade, also changes.If the torque acting on the first section is increased during operation of the multicopter - particularly quickly or even abruptly - this leads to a leading twist of the first section relative to the second section as seen in the direction of rotation of the first section due to the inertia of the second section with the rotor blade and due to the aerodynamic drag force acting against the direction of rotation, which leads to the angle of attack of the rotor blade and thus the thrust generated by the rotor device being increased. This in turn increases the aerodynamic drag, whereby an increase in speed is kept small or possibly even essentially avoided.

[0014] The inventive adaptive propeller structure with flexible elements achieves an automatic mechanical coupling of the blade pitch angle with the applied motor torque. This allows the multicopter to be controlled exclusively via motor power as usual. However, increasing motor power immediately provides greater thrust, as the propeller speed does not have to increase first. This is particularly advantageous for large propellers with a high moment of inertia, which would otherwise require a long time to accelerate.

[0015] In a further development, it is provided that the rotor device comprises a restoring device which at least temporarily urges the rotor blade in the direction of its rotational position towards an initial position, in particular comprises an elastic coupling device which elastically couples the second section to the first section. The elastic coupling is provided in the direction of rotation or counter to the direction of rotation of the first section. The relative rotation of one section to the other section thus takes place counter to a restoring force or counter to a restoring torque. This further improves the operation of the multicopter according to the invention.

[0016] In a further development of this, it is provided that the elastic coupling device comprises at least one elastic bending element, in particular comprises a plurality of elastic bending elements which are evenly distributed as seen in the circumferential direction of the rotor head, wherein the bending element or elements is or are connected at one end to the first section and at the other end to the second section. This is a structurally simple solution. Alternatively, a spiral spring arranged coaxially to the axis of rotation could be provided as the coupling device, or a tubular elastomer body arranged coaxially to the axis of rotation could be included in the coupling device. Furthermore, a bending element extending in the radial direction is also conceivable.

[0017] In a further development, the elastic coupling device has an at least approximately linear spring characteristic, preferably a progressive spring characteristic. Such a linear spring characteristic makes it possible to keep the speed more or less constant, even with a sudden increase in torque. With an appropriately dimensioned progressive characteristic, the constant speed is further improved, up to an at least approximately constant speed.

[0018] In a further development, the rotor device comprises a first stop, which at least indirectly limits the rotational movement of the rotor blade about the rotor blade axis in the direction of a "smaller angle of attack." This improves the reliability of the multicopter during operation, since a defined minimum angle of attack cannot be undercut in the event of torsional vibrations occurring between the two sections of the rotor device.

[0019] In a further development, the rotor device comprises a second stop which limits a rotational movement of the rotor blades about the rotor blade axis in the direction of a "larger angle of attack". This also improves the reliability of the multicopter during operation, since in the event of torsional vibrations occurring between the two sections of the rotor device or in the event of a significant increase in the torque acting on the first section from the drive, a defined maximum angle of attack cannot be exceeded. This defined maximum angle of attack is typically one at which, at typical speeds of the rotor device, no stall occurs on the rotor blade.

[0020] This is based on the knowledge that, particularly in the case of a sudden acceleration of the rotational speed of the rotor shaft, the torque can exceed the target torque at the new operating point by a multiple of one another. As a result, without the stop proposed here, the angle of attack of the rotor blade would also increase to a higher value than at the new operating point, which entails the risk that the rotor blade will stall before reaching the new operating point. However, at the stall point the profile drag and thus the rotor torque also increase by a multiple of one another. This would cause the rotor blade to remain in the stall region and a new equilibrium state in the stall state would be established. The technical implementation of the proposed stop is relatively simple. It could, for example, be realized using a part manufactured using 3D printing.

[0021] In a further development, the mechanical coupling comprises a driver lever that is rigidly connected to a rotor blade (attached to the second section of the rotor device) and that is coupled to a driver section of the first section. This is a particularly simple implementation from a technical perspective.

[0022] In a further development, the rotational movement of a rotor blade around the rotor blade axis is enabled by a twisting section that is integral with the rotor blade. This is also a particularly simple and cost-effective implementation.

[0023] Embodiments of the invention are explained below with reference to the accompanying drawings. The drawings show:

[0024] Figure 1: a schematic plan view of a multicopter; Figure 2: a perspective exploded view of a first embodiment of a rotor device of the multicopter of Figure 1;

[0025] Figure 3 is a perspective view of the rotor device of Figure 2 in a first operating state;

[0026] Figure 4 is a perspective view of the rotor device of Figure 2 in a second operating state;

[0027] Figure 5 is a diagram in which a torque of a

[0028] Rotor shaft of one of the rotor devices of Figures 2-4 is plotted against an angle of attack of a rotor blade;

[0029] Figure 6 is a diagram in which a speed of a

[0030] Rotor shaft of one of the rotor devices of Figures 2-4 is plotted against an angle of attack of a rotor blade;

[0031] Figure 7a is a diagram in which an angle of attack and a thrust of the rotor device of Figures 2-4 are plotted over time;

[0032] Figure 7b is a diagram in which a speed of the rotor device of Figures 2-4 is plotted against time; Figure 8 is a perspective view of a second

[0033] Embodiment of a rotor device of the multicopter of Figure 1;

[0034] Figure 9 is a perspective view of a third

[0035] Embodiment of a rotor device of the multicopter of Figure 1;

[0036] Figure 10 is an exploded perspective view of the rotor assembly of Figure 9;

[0037] Figure 11 is a perspective view of a fourth embodiment of a rotor device of the multicopter of Figure 1;

[0038] Figure 12 is an exploded perspective view of the rotor assembly of Figure 11;

[0039] Figure 13 is a perspective view of a fifth embodiment of a rotor device of the multicopter of Figure 1;

[0040] Figure 14 is a side view of the rotor assembly of Figure 13; and

[0041] Figure 15 is a plan view of the rotor assembly of Figure 13.

[0042] In the following, functionally equivalent elements and regions in different embodiments and in different figures bear the same reference symbols. They are usually explained in detail only when first mentioned. Furthermore, for reasons of clarity, not all reference symbols may be included in all figures.

[0043] A multicopter is designated overall by reference numeral 10 in Figure 1. It comprises a basic structure with, in the present case, four booms 12 extending radially outwards. At each end of each boom there is arranged a rotor device 14 with a rotational axis or rotor shaft 16 running perpendicular to the plane of the drawing, in the present case, for example, a rotor head 18 coupled to the rotor shaft 16 and, likewise in the present case, two rotor blades 20 fastened to the rotor head 18. In principle, multicopters with fewer or more than four rotor devices are also conceivable. As will be explained further below, designs of rotor devices are also conceivable which do not have a discrete rotor head. Furthermore, designs of rotor devices are conceivable which have only one rotor blade and a corresponding counterweight, or which have more than two rotor blades.The rotor blades 20 are each rotatable relative to the rotor head 18 about a rotor blade axis 22. The rotor blade axis 22 is shown in Figure 1 only for two rotor blades 20.

[0044] Each rotor device 14 also has an electric drive motor, which is not visible in Figure 1, however. The electric drive motor is connected to the rotor shaft 16. Furthermore, the multicopter 10 includes a control and regulating device, also not shown in Figure 1, which can individually control the electric drive motors of the rotor devices 14 in order to control the multicopter in a known manner. A first possible embodiment of the rotor devices 14 will now be explained with reference to Figures 2-4, as an example for a rotor device 14. The rotor device 14 or the rotor head 18 of the rotor device 14 comprises a lower first section 24 and an upper second section 26. Both sections 24 and 26 are designed here, by way of example, as essentially circular disks.The lower first section 24 has a central, upwardly facing tubular receiving pin 28, into which a likewise central, downwardly facing axle pin (not visible) of the second section 26 engages. In this way, the second section 26 is rotatably mounted on the first section 24 and arranged coaxially to rotate and move therewith. Furthermore, the first section 24 is firmly or rigidly connected to the rotor shaft 16, indicated only by a dot-dash line.

[0045] The two rotor blades 20 are attached to the second section 26 and, as already mentioned above, are rotatably mounted relative to the rotor head 18 about the rotor blade axis 22. For this purpose, the second section 26 has two tubular receiving pins 30 pointing in the radial direction, into which a respective radially inwardly pointing axle pin 32 of a rotor blade 20 engages.

[0046] The rotor head 18 also includes two mechanical couplings 34, each of which is assigned to a rotor blade 20. Since both mechanical couplings 34 are constructed identically, only one of the two mechanical couplings 34 will be described below. The mechanical coupling 34 here comprises, by way of example, a driver lever 36 which is rigidly connected to the rotor blade 20. The driver lever 36 projects downwards in the direction of the first section 24 in the region of a root 38 of the rotor blade 20, orthogonal to the rotor blade axis 22. The mechanical coupling 34 further comprises a driver section 40 which is coupled to the first section 24.

[0047] In the present example, the driver section 40 is designed as a receiving opening that is open radially outwards and is formed between two rod-shaped extensions 42 that extend radially outwards from the first section 24. The driver lever 36 is received in the driver section 40 with a slight amount of play. As will be explained later, the mechanical coupling 34 automatically and mechanically couples a torque-dependent position of the first section 24 relative to the second section 26 with a rotational position of the rotor blade 20 about the rotor blade axis 22 and thus with an angle of attack of the rotor blade 20.

[0048] The rotor device 14 further comprises an elastic coupling device 44 which elastically couples the second section 26 to the first section 24. In the present case, highly schematically and by way of example, the elastic coupling device 44 comprises a spiral spring, one end of which is connected to a rod-shaped holding section 46 extending downwards from the second section 26, and the other end of which is connected to a rod-shaped holding section 48 extending upwards from the first section 24. The elastic coupling device 44 shown here by way of example is a tension spring. The two holding sections 46 and 48 are therefore urged towards one another by the elastic coupling device 44.

[0049] The rotor device 14 further comprises a first stop 50 and a second stop 52. The two stops 50 and 52 are formed in the present case by the axial end regions of a circumferentially extending slot 54, which is formed in the lower first section 24 and into which the holding section 46 engages. The relative rotational movement of the second section 26 relative to the first section 24 is thus limited to the angular range between the first stop 50 and the second stop 52.

[0050] The operation of the rotor device 14 will now be explained in particular with reference to Figures 3 and 4. Figure 3 shows the rotor device 14 in a first operating state, in which the rotor shaft 16 and with it the two sections 24 and 26 of the rotor device 14 rotate at a constant speed, driven by the aforementioned electric drive motor. The rotational movement is indicated in Figures 3 and 4 by arrows 56.

[0051] In the first operating state shown in Figure 3, the holding section 46 of the second section 26 is pulled by the elastic coupling device 44 against the first stop 50. In this relative position of the two sections 24 and 26, the driver lever 36 projects downwards substantially parallel to the rotor shaft 16. Accordingly, an angle of attack (not shown) of the two rotor blades 20 is comparatively small. Thus, the first stop 50 limits a rotational movement of the two rotor blades 20 about the rotor blade axis.

[0052] 22 towards "smaller angle of attack".

[0053] Figure 4 shows the rotor device 14 in a second operating state immediately after an increase in the torque ("drive torque") acting from the electric drive motor on the rotor shaft 16 and thus on the first section 24. Due to the increased drive torque, the lower first section 24, which is rigidly coupled to the rotor shaft 16, is rotated in advance of the second section 26 in the direction of rotation 56. As a result, the elastic coupling device 44 is stretched, and the holding section 46 is moved in the slot 54 against the second stop 52, according to an arrow 57 in Figure 4.

[0054] Due to the relative rotation between the first section 24 and the second section 26, the driver lever 36 is driven by the driver section 40 (automatic mechanical coupling), whereby the respective rotor blade 20 is rotated about the rotor blade axis 22 such that the angle of attack of the respective rotor blade 20 is increased. Thus, the second stop 52 limits a rotational movement of the two rotor blades 20 about the rotor blade axis 22 in the direction of a "larger angle of attack". The second stop 52 is selected such that the maximum aerodynamically sensible angle of attack of the rotor blades 20 is prevented from being exceeded.

[0055] The larger angle of attack results in greater thrust from the rotor device 14. Furthermore, the increased angle of attack of the two rotor blades 20 increases the aerodynamic drag of the two rotor blades 20, exerting a counter-torque on the rotor shaft 16 that opposes the drive torque exerted by the electric motor on the rotor shaft 16. This means that even a sudden increase in the drive torque, if any, leads only to a comparatively small increase in the speed of the rotor shaft 16.

[0056] How the speed and thrust behave when the drive torque changes depends to a considerable extent on the characteristics of the elastic coupling device 44.

[0057] A speed that is almost constant over a wide range can be achieved even in the event of a sudden change in the drive torque using an elastic coupling device 44 that has at least approximately linear elastic behavior, i.e. an at least approximately linear spring characteristic. This is shown in the diagrams in Figures 5 and 6, in which the drive torque M on the rotor shaft 16 or the first section 24 is plotted against the angle of attack A of the rotor blades 20 (Figure 5) and the speed R of the rotor shaft 16 or the first section 24 is plotted against the thrust T (Figure 6). In Figure 5, the actual torque is shown as a solid line, whereas the dashed line represents the idealized approximation of the actual torque using linear spring elements.In Figure 6, the actual speed of rotation is plotted as a solid line for the rotor device 14 of Figures 1-4, and as a dashed line for a conventional propeller.

[0058] If an even more constant speed is required when the drive torque changes, then this can be achieved with an elastic coupling device 44 which has progressive elastic behavior, i.e. a progressive spring characteristic curve. This is shown in Figures 7a and 7b, in which the angle of attack A and the thrust T are plotted against time t in one diagram and the speed R is plotted against time t in the other diagram. The sudden change in the drive torque, which is used as an example here, occurs at a time t1. The solid lines correspond to the behavior of the rotor device 14 in Figures 1-4, the dashed lines to a conventional propeller.

[0059] An alternative embodiment of a rotor device 14 is shown in Figure 8. This differs from the embodiment in Figures 2-4 primarily in the design of the elastic coupling device 44. In the present case and highly exemplary, this comprises a plurality of elastic bending elements 58, which in turn are arranged, highly exemplary, evenly distributed in the circumferential direction of the sections 24 and 26. The bending elements 58 are designed in the form of rectangular bending plates, for example made of GRP or CFRP, which are flat and planar in the unloaded state, the longitudinal axis of which runs parallel to the axis of the rotor shaft 16 and the planes of which are aligned radially. An upper end of a bending element 58 in Figure 8 is received in a receiving section 60 of the upper second section 26 of the rotor device 14 and fastened there.A lower end of a bending element 58 in Figure 8 is received in a receiving section 62 of the lower first section 24 of the rotor device 14 and fastened there.

[0060] When the drive torque changes, which is applied to the

[0061] Rotor shaft 16 and thus acts on the lower first section 24 of the rotor device 14, the bending elements 58 are bent from their straight, flat shape shown in Figure 8 into a bent, curved shape by the lower first section 24 leading in the direction of rotation 56.

[0062] In the embodiment of Figures 9 and 10, the rotary movement of a rotor blade 20 is made possible by a twisting section 64 which is integral with the rotor blade 20. This twisting section is elastically twisted when the rotor blade 20 rotates about the rotor blade axis 22. The twisting section 64 is preferably made of a suitable plastic material. Due to its elasticity, the connecting section 64 additionally acts as an elastic coupling device 44, as described above. The two rotor blades 20 are fastened to the upper second section 26 of the rotor head 18 in the exemplary embodiment shown in Figures 9 and 10 by means of screws 66.

[0063] In the embodiment of Figures 11 and 12, two star-shaped elastic coupling devices 44 are pushed onto the rotor shaft 16 and rigidly fastened thereto, for example by adhesive bonding. Each of the two elastic coupling devices 44 has a central body 68 which is pushed onto the rotor shaft 16 and adhesively bonded thereto. Four plate-shaped, elongated bending elements 58 extend radially outward in a star shape from the central body 68. These can be made, for example, from a thin plastic material, optionally with fiber reinforcement, for example glass fibers or carbon fiber.

[0064] A hollow, cylindrical coupling ring 70 is firmly connected to the drive motor (not shown), which may be a brushless electric motor, for example, and whose rotating section (not shown). This coupling ring has 2 x 4 receiving sections 62 on its inside for receiving the projecting ends of the flexural elements 58. The flexural elements 58 can be glued into the receiving sections 62, for example. In this way, the rotor shaft 16 is connected to the coupling ring 70 in a flexurally elastic manner via the flexural elements 58.

[0065] Rigidly attached to the upper end of the rotor shaft 16 in Figures 11 and 12 is a receiving section 72 having receiving slots 74 extending transversely to the longitudinal axis of the rotor shaft 16. Four leaf-like, elongated fastening tongues 76 of two rotor blades 20 can engage in these slots. The four fastening tongues 76 are, for example, glued into the complementary receiving slots 74.

[0066] The fastening tongues 76 extend from the root 38 of a rotor blade 20 at least approximately parallel to the rotor blade axis 22 such that a radially outer narrow side 77 of the fastening tongues 76 lies on an imaginary enveloping cylinder wall. Or, in other words: the blade planes of two opposite fastening tongues 76 lie in the same plane, whereas the blade planes of two connecting tongues 76 adjacent in the circumferential direction are orthogonal to one another. It is understood that in other embodiments there may be more or fewer than four fastening tongues, or a completely different form of torsionally elastic but flexurally rigid coupling may be present. The fastening tongues 76 are made of a thin plastic material, optionally with fiber reinforcement, for example glass fibers or carbon fibers.They can be very thin, for example, in the range of a thickness of only 0.2 mm. The fastening tongues 76 connect the two rotor blades 20 to the receiving section 72 in a manner that is, on the one hand, very rigid about axes orthogonal to the rotor blade axis 22, but, on the other hand, elastically rotatable about the rotor blade axis 22. In this respect, the fastening tongues 76 form the twisting section 64 already mentioned above.

[0067] From the root 38 of a rotor blade 20, the driver lever 36 extends orthogonally to the rotor blade axis 22, the projecting end of which is connected in the present case, for example, to a bending element 78 which extends on the outside of the coupling ring 70 from a radially projecting fastening section 80 approximately in the circumferential direction of the coupling ring 70.

[0068] During operation, the coupling ring 70 is rotated by the drive motor, and the rotor shaft 16 and, with it, the two rotor blades 20 are also rotated via the elastic coupling devices 44. If the torque of the drive motor is increased, the coupling ring 70 advances ahead of the receiving section 72, as already explained above in connection with the other embodiments. In this case, the bending elements 58 are bent in the same direction.

[0069] By changing the relative position between the coupling ring 70 on the one hand and the receiving section 72 on the other hand, and by the mechanical coupling 34 of the rotor blades 20 to the coupling ring 70 by the driver lever 36, the two rotor blades 20 are rotated about the rotor blade axis 22 in the direction of larger angles of attack. In this respect, the coupling ring 70 forms the above-described "first section 24," and the receiving section 72 forms the above-mentioned "second section 26."

[0070] In the embodiment of a rotor device 14 shown in Figures 13-15, the rotor shaft 16 is fastened with a flat fastening flange 70, which in turn can be connected to the rotating section of the drive motor (not shown). As in the embodiment of Figures 11-12, the two rotor blades 20 are connected to the receiving section 72 via fastening tongues 76. In a particularly preferred embodiment, the fastening flange 70, rotor blades 20, fastening tongues 76 and receiving section 72 / rotor shaft 16 are manufactured as a one-piece part, for example by an injection molding process or by 3D printing, for example from plastic.

[0071] A special feature of the embodiment of Figures 13-15 is that the rotor blade axis 20 is arranged offset upwards by a distance 84 in a direction parallel to the rotor shaft 16 relative to a central axis 82 of the unit formed from the four fastening tongues 76. In an upper end face of the rotor shaft 16, shown in the figures, there are two recesses 54 which are slightly laterally offset from one another and into which a pin 46 engages, extending parallel to the rotor blade axis 22 from the root 38 to the rotor shaft 16. The drive motor (not shown) again causes the fastening flange 70 to rotate, and with it the two rotor blades 20 are rotated via the rotor shaft 16.When the torque increases, the rotor blades 22 tilt backward, due to the distance 84 around the central axis 82, against the direction of rotation 56, again due to inertia and aerodynamic drag forces, resulting in an increase in the angle of attack. This rotation is in turn enabled by the elastic fastening tongues 76, which also generate the necessary restoring force against the tilting direction of the rotor blades 20.

[0072] In this respect, the fastening tongues 76 also form the above-mentioned twisting section 64, into which the elastic coupling device 44 is integrated. The entirety of the fastening flange 70 and the rotor shaft 16 forms the above-mentioned rotatably driven first section 24, whereas the two rotor blades 20 form the above-mentioned second section 26, or are encompassed by it, which is movable relative to the first section 24 about an axis that runs parallel to the axis of rotation or the rotating shaft 16, due to the tilting movement.

[0073] The mechanical coupling 34, which couples the relative position of the first section 24 relative to the second section 26 with a rotational position of the rotor blade 20 about the rotor blade axis 22, is realized in the present case by the distance 84 between the two axes 22 and 82.

[0074] The recesses 54 form with their lateral ends first and second stops 50 and 52, by which the maximum and minimum tilt angle and thus the maximum and minimum angle of attack of the rotor blades 20 are limited.

Claims

A multicopter (10) comprising a plurality of rotor devices (14), wherein a rotor device (14) comprises at least one rotor blade (20) which is rotatable about a rotor blade axis (22), characterized in that the rotor device (14) has: a first section (24) which is driven rotatably about a rotational axis (16), a second section (26) which is movable relative to the first section (24) about an axis which runs parallel to the rotational axis (16) and to which the rotor blade (20) is fastened or which comprises the rotor blade (20), wherein a relative position of the second section (26) to the first section (24) depends on a torque (M) with which the first section (24) is driven, and a mechanical coupling (34) which links the relative position of the first section (24) relative to the second section (26) with a rotational position of the rotor blade (20) about the rotor blade axis (22). coupled.Multicopter (10) according to claim 1, characterized in that the rotor device (14) comprises a return device (44) which at least temporarily acts on the rotor blade (20) in the direction of an initial position with regard to its rotational position, in particular comprises an elastic coupling device (44) which resets the second. Section (26) elastically and at least indirectly coupled to the first section (24). Multicopter (10) according to claim 2, characterized in that the elastic coupling device (44) comprises at least one elastic bending element (58), in particular comprises a plurality of elastic bending elements (58) which, viewed in the circumferential direction of the first section (24), are preferably arranged so as to be evenly distributed, wherein the bending element (58) or the bending elements (58) is or are connected at one end to the first section (24) and at the other end to the second section (26). Multicopter (10) according to at least one of claims 2 or 3, characterized in that the elastic coupling device (44) has an at least approximately linear spring characteristic, preferably a progressive spring characteristic.Multicopter (10) according to at least one of the preceding claims, characterized in that the rotor device (14) comprises a first stop (50) that at least indirectly limits a rotational movement of the rotor blade (20) about the rotor blade axis (22) in the direction of a "smaller angle of attack." Multicopter (10) according to at least one of the preceding claims, characterized in that the rotor device (14) comprises a second stop (52) that at least indirectly limits a rotational movement of the rotor blade (20) about the rotor blade axis (22) in the direction of a "larger angle of attack." Multicopter (10) according to at least one of the preceding claims, characterized in that the mechanical coupling (34) comprises a driver lever (36) that is rigidly connected to the rotor blade (20) and coupled to a driver section (40) of the first section (24). Multicopter (10) according to at least one of the preceding claims, characterized in that the rotational movement of the rotor blade (20) about the rotor blade axis (22) is enabled by a twisting section (64) that is integral with the rotor blade (20).Rotor device (14) for a multicopter (10), which comprises at least one rotor blade (20) which is rotatable about a rotor blade axis (22), characterized in that it has: a first section (24) which is driven so as to be rotatable about an axis of rotation (116), a second section (26) which is movable relative to the first section (24) about an axis which runs parallel to the axis of rotation (16) and to which the rotor blade (20) is fastened, wherein a relative position of the second section (26) to the first section (24) depends on a torque (M) with which the first section (24) is driven, and a mechanical coupling (34) which couples the relative position of the first section (24) relative to the second section (26) to a rotational position of the rotor blade (20) about the rotor blade axis (22).

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