Locking system for a tilting system of an aircraft

Abstract

The present invention relates to a locking system (40) for a tilting system (10) of an aircraft, in particular a VTOL aircraft, as well as to a tilting system (10) and an aircraft comprising the locking system (10) according to the invention. The locking system (40) comprises a locking element (41) which is designed and arranged to be movable in one direction with respect to a fastening element (1231) to which the locking element (41) is fastened, a ring element (1225) comprising at least one locking counter-element (44a, 44b) which is designed to receive the locking element (41) in a locked state of the locking system (40), a spring element (45) which is designed and arranged to apply a force to the locking element (41), wherein the locking counter-element (44a, 44b), the locking element (41) and the spring element (45) are designed such thatthat when a defined limit torque on the ring element (1225) is exceeded, the locking element (41) is pressed out of the locking counter-element (44a, 44b) due to a rotation of the ring element (1225) against the force of the spring element (45) in order to transfer the locking system (40) into an unlocked state.

Description

[0001] The present invention relates to a locking system for a tilting system of an aircraft, in particular a VTOL aircraft, as well as a tilting system and an aircraft with the locking system according to the invention.

[0002] VTOL aircraft are capable of vertical takeoff and landing without moving horizontally ("vertical takeoff and landing"). In other words, VTOL aircraft have propulsion units capable of generating thrust in the aircraft's vertical direction, and thus in the direction of the yaw axis. Various types of propulsion units and aircraft concepts are known from the prior art for generating this thrust. For the purposes of this application, a propulsion unit is understood to mean any device that generates thrust capable of propelling an aircraft. In particular, a propulsion unit within the scope of this application relates to propellers, in particular jet propellers and fans. Propulsion units such as jet propellers or open propellers can be arranged in the fuselage or wings of an aircraft to generate thrust in the vertical direction.Document US 20 2014 8376 A1 discloses an aircraft having a plurality of propellers, each of which is connected to an electric drive motor via a coupling. Document WO 2023 183 515 A1 discloses an aircraft having a propeller and a drive device with two electric motors mounted on the propeller, the propeller being arranged to generate vertical thrust.

[0003] Other propulsion unit concepts include a movable and adjustable thrust channel to direct the thrust in the desired direction in a specific flight mode.

[0004] Some aircraft concepts for VTOL aircraft use tilt systems to tilt the propulsion unit according to the aircraft's flight mode. When the aircraft is about to take off or land vertically, the propulsion units are oriented to generate thrust in the aircraft's vertical direction. When the aircraft is in a regular cruise mode, the propulsion units can be rotated to provide thrust along the aircraft's roll (longitudinal) axis. Document DE 60017567 T2 describes an aircraft with multiple propellers that can be adjusted between a vertical orientation and a horizontal orientation, wherein multiple propulsion units are provided, each of which can adjust one propeller or, by actuating at least one hydraulic clutch, multiple propellers.By means of the hydraulic coupling, the propellers can be connected to a common shaft in order to drive several propellers via a single drive unit. Document WO 2021255374 A1 discloses a tiltable propeller of an aircraft, wherein the propeller can be coupled to a propeller motor via a coupling. Document US 6,719,244 B1 describes an adjustment device for two propellers of a VTOL, in which the two propellers can be adjusted between a vertical and a horizontal orientation and a separate drive unit is provided for adjusting the propellers for each propeller. Document WO 2015 / 189684 A1 describes a VTOL with two jet propellers, each provided on a wing and adjustable between a horizontal and vertical orientation, wherein the jet propellers can be adjusted by a redundant adjustment device with two actuators.Document EP 3 838 753 A1 discloses a redundant propulsion system for multiple propellers of a VTOL.

[0005] To lock the propulsion units in a specific position, particularly in a vertical or horizontal position, the tilt systems may include locking mechanisms. In a vertical position / state / orientation, the propulsion unit generates thrust in a vertical direction of the aircraft along its yaw axis. In a horizontal position / state / orientation, however, the propulsion unit generates thrust in a horizontal direction of the aircraft. The vertical state is used for hover mode during vertical takeoff and landing, while the horizontal state is used during the aircraft's normal cruise mode in the horizontal direction.

[0006] Various locking systems or locking devices are disclosed in the prior art. Document KR 20170132996 A discloses a propeller of a VTOL that can be adjusted between a vertical orientation and a horizontal orientation, wherein the propeller can be fixed in the various orientations by a lever-like locking element that interacts with a corresponding opening in the propeller. The locking element can be actively actuated by an actuator. Document CN 108216618 A discloses a locking device for locking a propeller of a VTOL that can be adjusted between various positions, wherein a locking element is coupled to an adjustment device such that the locking element is displaced from a locking position to a release position by actuating the adjustment device.The propeller can only be adjusted once the locking element has been moved into the release position. Document WO 2019073417 A1 describes another embodiment of a locking device for an adjustable jet propeller of an aircraft.

[0007] Against the background of the prior art outlined above, the object of the present invention is to provide an alternative locking system for a tilting system of an aircraft, with which a specific position of a drive unit can be locked. A further object is to provide a locking system with minimal energy consumption and low complexity in terms of design, assembly, and maintenance. Furthermore, a tilting system and an aircraft with the locking system according to the invention are to be provided.

[0008] This object is achieved by the subject matter of the independent claims. Advantageous embodiments of the locking system according to the invention are disclosed in the dependent claims.

[0009] The locking system according to the invention for a tilting system of an aircraft, in particular a VTOL aircraft, comprises a locking element that is designed and arranged to be movable in one direction with respect to a fastening element to which the locking element is attached, a ring element comprising at least one locking counter-element that is designed to receive the locking element in a locked state of the locking system, a spring element that is designed and arranged to apply a force to the locking element, wherein the locking counter-element, the locking element, and the spring element are designed such that when a defined limit torque on the ring element is exceeded, the locking element is pressed out of the locking counter-element due to a rotation of the ring element against the force of the spring element,to bring the locking system into an unlocked state.

[0010] The term "fastening element" refers to an element that cannot be moved and is therefore fixed. The locking element is attached to the fastening element. However, it does not have to be directly attached to it. The position of the locking counter-element defines the position in which the ring element, and thus the locking system, is locked. The locked state of the locking system therefore defines a state in which rotation of the ring element is not possible. The ring element is connected directly or via any power transmission to a shaft of the tilting system to which the aircraft's drive units are connected. This means that when the locking system and thus also the ring element are locked, the tilting movement of the shaft and thus the drive unit is prevented. The locked state remains until a certain, predefined limit torque is applied to the ring element.If the limit torque is exceeded, the locking element is moved out of the locking counter-element due to the shape of the locking element and the locking counter-element and pressed against the force exerted on the locking element by the spring element. Preferably, the locking element and the locking counter-element should be shaped and designed such that their resistance to rotational movement of the ring element is minimal. This means that the limit torque is primarily defined by the spring stiffness of the spring element. The term "spring element" refers to any element that can be elastically deformed and can therefore exert a force on the locking element in an at least partially deformed state.Therefore, the spring element is preferably designed to apply a force to the locking element that is high enough to hold the locking element in the locking counter-element during normal operation of the aircraft, so that any force exerted by the drive unit on the ring element can be absorbed by the locking system. On the other hand, the spring element is preferably designed to apply a force to the locking element that is low enough to overcome a force or torque provided by an actuator of the tilting system so that the locking system transitions from a locked state to an unlocked state. In the unlocked state, the locking element is not absorbed by the locking counter-element.

[0011] In this way, a locking system can be provided that operates without an additional actuator for unlocking or locking the locking system. Transitioning from an unlocked state to a locked state is performed automatically by the actuator of the tilting system itself. An additional actuator is therefore not required. Furthermore, the locking system is robust and has low maintenance requirements and can be implemented using simple technical features.

[0012] In an advantageous embodiment of the invention, the locking element has a cylindrical shape and preferably a circular cross-section. Furthermore, it is preferably arranged to rotate about a rotation axis, or it comprises a casing that is rotatably attached to a body of the locking element. These features make it possible to reduce the resistance caused by the shape and properties of the locking element when leaving the locking counter-element when the locking system is transferred from a locked state to an unlocked state or vice versa. The rotatable design of the locking element itself or of the casing results in the effect that the locking element can easily roll over the locking counter-element.This is preferable because, due to the shape and properties of the locking element and the locking counter-element, a lower resistance results in a greater influence of the spring element on the resistance that must be overcome by the limiting torque. The influence of the spring element can be easily defined by defining a corresponding spring resistance. Consequently, the limiting torque for changing from a locked to an unlocked state can be defined more precisely.

[0013] For the same reason, an embodiment of the invention is preferred in which the locking counter-element has a round shape. This means that the locking counter-element has no sharp edges. Preferably, the locking counter-element is formed by a recess between two preferably round-shaped elevations on the ring element, and the recess is preferably shaped to correspond to a cross-section of the locking element. In other words, the locking element and the locking counter-element have at least partially oppositely shaped cross-sections.

[0014] In a further advantageous embodiment of the invention, the locking system further comprises a rotary element that is rotatably mounted on one side of the fastening element at a pivot point, wherein the locking element and preferably also the spring element are directly connected to the rotary element. The rotary element can define the movement of the locking element attached thereto. However, other embodiments are also possible in which the locking element is guided in a guide of the fastening element.

[0015] The tilting system according to the invention for at least one drive unit of an aircraft comprises a locking system according to the invention.

[0016] Preferably, the ring element of the locking system is arranged around an output shaft of an actuator of the tilting system or around a shaft of the tilting system to which the drive unit is connected.

[0017] The aircraft according to the invention comprises a tilting system according to the invention.

[0018] Advantageous aspects and embodiments of the invention are explained in more detail below with reference to the attached figures. Fig. 1 shows a schematic view of a tilting system 10 according to the invention for two drive units 20 of an aircraft. Fig. Figure 2a shows a cross-sectional view of an actuating system 12 used in a tilting system 10 according to Fig. 1 is used, in a horizontal state of the drive units 20. Fig. 2b shows a cross section through the actuation system 12 according to Fig. 2a in a vertical state of the drive units 20. Fig. 3 shows a detailed view of a locking system 40 in an embodiment according to the invention.

[0019] Fig. Figure 1 shows a schematic view of a tilting system 10 from a bird's eye view in an embodiment according to the invention. The tilting system 10 is designed to rotate two propulsion units 20 of an aircraft by at least 90 degrees from a horizontal position / state (shown in Fig. 1) in a vertical position / state. Designs are also possible in which the tilting system 10 rotates the drive units 20 by more than 90 degrees. The horizontal position of the drive units 20 is characterized in that the thrust generated by the drive units 20 is directed along a longitudinal axis of the aircraft, referred to as the roll axis x. The vertical position of the drive units 20, on the other hand, is characterized in that the thrust generated by the drive units 20 is directed along a vertical axis of the aircraft, referred to as the yaw axis, which is Fig. 1 extends into the drawing plane.

[0020] The tilting system 10 comprises a shaft 11 which extends through the fuselage 30 of the aircraft and is attached thereto via a plurality of bearings 13 so that the shaft 11 can rotate about its shaft axis y. In the Fig. In the embodiment shown in Figure 1, the shaft axis y corresponds to a transverse axis of the aircraft, which is referred to as the pitch axis. The drive units 20 according to the embodiment shown in Fig. The embodiment shown in Figure 1 is designed as jet propellers. However, the tilting system 10 according to the invention is also suitable for any type of drive unit, such as open propellers or turbines. The connection between the shaft 11 and the drive units 20 is designed to absorb a torque about the shaft axis y, so that the drive units 20 rotate when the shaft 11 rotates about its shaft axis y.

[0021] In the embodiment shown, two drive units 20 are connected to the shaft 11, with each drive unit 20 located on each side of the aircraft's fuselage 30. Other embodiments of the tilting system 10 according to the invention, in which more than two or only one drive unit 20 is connected to the shaft, are also possible.

[0022] In addition, an actuating system 12 is arranged for rotating the shaft 11 and thus also the drive units 20 from a horizontal position to a vertical position and vice versa. The actuating system 12 is described with reference to the Fig. 2a and Fig. 2b.

[0023] Fig. 2a and Fig. 2b show a cross-sectional view of an actuating system 12 used in the tilting system 10 according to Fig. 1 is used. Fig. Figure 2a shows the actuation system 12 in a state in which the drive units 20 are in a horizontal position, while Fig. Figure 2b shows the actuation system 12 in a state in which the drive units 20 are in a vertical position.

[0024] The shaft 11 is attached to the fuselage 30 of the aircraft via a bearing 13, whereby a rotation about the shaft axis y (along a direction in the plane of the drawing of Fig. 2a and Fig. 2b) is possible. To effect the rotation, an actuator 123 in the form of an electric motor is provided, which drives a power transmission 122. The power transmission 122 is connected to a connecting element 121, which transmits a torque provided by the actuator 123 and the power transmission 122 to the shaft 11. The power transmission 122 is formed by a transmission element 1221, which connects a first lever arm 1222 on one side and a second lever arm 1224 on the other side. Both connections are formed by pivot bearings 1223. The second lever arm 1224 is connected to an output shaft of the actuator 123. The actuator 123 can be designed, for example, as an electric motor.

[0025] The connecting element 121 can be designed as a clutch that, in the engaged state, enables the power transmission as described above and, in the disengaged state, does not transmit the power to the shaft 11. Preferably, the clutch is designed as an electromagnetic clutch to enable short reaction times of the clutch.

[0026] A rotary movement of the actuator 123 is transmitted to the connecting element 121 and the shaft 11 via the second lever arm 1224, the transmission element 1221 and the first lever arm 1222. Consequently, the shaft 11 can be rotated by actuating the actuator 123 and from the Fig. 2a shown position into the Fig. 2b. Other types of actuators 123, such as linear actuators, are also conceivable.

[0027] The tilting system 10 further includes a locking system 40, which in the illustrated embodiments is arranged on the actuator 123. In other embodiments, the locking system 40 can also be arranged on the shaft 11.

[0028] The locking system 40 is described with reference to Fig. 3 is explained in more detail. Fig. Figure 3 shows the actuator 123 and parts of the power transmission 122, such as the second lever arm 1224 and the transmission element 1221 with the pivot bearing 1223 located therebetween. The second lever arm 1224 is formed integrally with a ring element 1225, which encloses an output shaft 1232 of the actuator 123. In other embodiments, the second lever arm 1224 and the ring element 1225 are not formed integrally, but are connected to one another. The ring element 1225 does not necessarily have to be shaped as a closed ring, but can also be shaped, for example, as a ring section.

[0029] A fastening element 1231 is attached to the actuator 123 in such a way that it is not movable. A rotary element 42 is attached to the fastening element 1231 via a pivot point 43 about which the rotary element 42 can be rotated. A locking element 41 is attached to the rotary element 42 such that the locking element 41 is attached to the fastening element 1231 via the rotary element 42. In the Fig. In the state shown in Figure 3, the locking element 41 is received by a first locking counter-element 44a, which is arranged on the ring element 1225. A second locking counter-element 44b is also arranged on the ring element 1225, which is offset by an angle of 180 degrees from the first locking counter-element 44a. The locking counter-elements 44a, 44b are each formed by a recess 442 located between two elevations 441. Both the elevations 441 and the recess 442 have a round shape without edges.

[0030] The locking element 41 is formed from a cylindrical body 411 and a casing 412 surrounding the body 411. The casing 412 is rotatably mounted around the body 411. A cross-sectional shape of the locking element 41 is partially opposite to the cross-sectional shape of the recess 442 of the locking counter-elements 44a, 44b. In other words, the diameter of the cylindrical shape of the locking element 41 corresponds to the diameter of the recess 442, so that the locking element 41 can be received in the locking counter-elements 44a, 44b by a partial positive fit.

[0031] Furthermore, a spring element 45 is attached to the rotating element 42 and a clamping element 46, which in turn is connected to the fastening element 1231. As a result, the spring element 45 is clamped between the immovable clamping element 46 and the rotating element 42 and thus subjected to a preload. The preload, in turn, exerts a force on the rotating element 42 in a direction in which the locking element 41 attached to the rotating element 42 is pressed into the recess 442 of the first locking counter-element 44a.

[0032] The Fig. The locking system 40 shown in Figure 3 is shown in the locked state. If, during normal operation of the aircraft, a force or torque is applied by the drive unit 20 to the ring element 1225 via the load path of the power transmission 122, the locking element 41 does not exit the first locking counter-element 44a. In a locked state, the actuator 123 is thus freed from all forces of the drive units 20 that could be transmitted via the power transmission 122 during operation of the drive units 20.

[0033] In order for the locking system 40 to change from a locked state to an unlocked state, the actuator 123 exerts a torque about a rotational axis r on the ring element 1225 in the direction of the Fig.3 (clockwise). When a defined limit torque is exceeded, the locking element 41 creeps up the elevation 441 on the side of the recess 442 of the first locking counter-element 44a against the force applied by the preloaded spring element 45 until it is no longer received by the first locking counter-element 44a. The round-shaped elevations 441 and recesses 442, as well as the cylindrical shape and the rotatable casing 412 of the locking element 41, offer the least possible resistance to the movement of the ring element 1225, so that the limit torque required to override the state of the locking system 40 is determined almost exclusively by the force exerted by the spring element 45 on the rotating element 42. Consequently, the value of the limit torque can be defined by the spring stiffness of the spring element 45.The limit torque is preferably defined such that it is sufficiently large so that a force transmitted from the drive unit 20 to the ring element 1225 during operation of the aircraft does not cause the locking system 40 to leave the locked state, but is small enough so that the locked state can be left by applying the torque by the actuator 123.

[0034] The torque of the actuator 123 is applied until the ring element 1225 is rotated 180 degrees and the locking element 41 is received by the second locking counter-element 44b. The locking system 40 is thus again in a locked state, but in a different position than before. The different positions of the locking counter-elements 44a, 44b therefore mark the different positions in which the shaft 11 and the connected drive units 20 can be locked. Preferably, a locking state is marked by a position in which the drive units 20 are in a horizontal state for cruise mode, and a locking state is marked by a position in which the drive units 20 are in a vertical state for vertical thrust and hover mode during vertical takeoff and landing.

[0035] In other embodiments, more different locking counter elements 44a, 44b may be arranged on the ring element 1225 to provide more different locking positions for the drive units 20.

[0036] The locking system 40 according to the invention represents a structurally simple possibility of providing a locking system 40 for a tilting system 10 of drive units 20 without an additional actuator for actuating the locking effect, and also forms a robust and low-maintenance solution. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 20 2014 8376 A1

[0002] WO 2023 183 515 A1

[0002] DE 60017567 T2

[0004] WO 2021255374 A1

[0004] US 6 719 244 B1

[0004] WO 2015 / 189684 A1

[0004] EP 3 838 753 A1

[0004] KR 20170132996 A

[0006] CN 108216618 A

[0006] WO 2019073417 A1

[0006]

Claims

[1] Locking system (40) for a tilting system (10) of an aircraft, comprising a locking element (41) designed and arranged to be movable in one direction with respect to a fastening element (1231) to which the locking element (41) is attached, a ring element (1225) comprising at least one locking counter-element (44a, 44b) designed to receive the locking element (41) in a locked state of the locking system (40), a spring element (45) designed and arranged to exert a force on the locking element (41), wherein the locking counter-element (44a, 44b), the locking element (41) and the spring element (45) are designed such that when a defined limit torque on the ring element (1225) is exceeded, the locking element (41) is pressed out of the locking counter-element (44a, 44b) by a rotation of the ring element (1225) against the force of the spring element (45) in order to transfer the locking system (40) into an unlocked state. [2] Locking system (40) according to the preceding claim, wherein the locking element (41) has a cylindrical shape, preferably with a circular cross-section. [3] Locking system (40) according to one of the preceding claims, wherein the locking element (41) is arranged to be rotatable about an axis of rotation. [4] Locking system (40) according to one of the preceding claims 1 or 2, wherein the locking element (41) comprises a casing (412) rotatably mounted on a body (411) of the locking element (41). [5] Locking system (40) according to one of the preceding claims, wherein the locking counter-element (44a, 44b) is formed by a recess between two preferably round-shaped elevations (441) and the recess is preferably shaped according to a cross-section of the locking element (41). [6] Locking system (40) according to one of the preceding claims, wherein the locking system (40) further comprises a rotary element (42) which is rotatably attached on one side to a fastening element (1231) via a pivot point (43), wherein the locking element (41) and preferably also the spring element (45) are directly connected to the rotary element (42). [7] Tilting system (10) for at least one drive unit (20) of an aircraft, comprising a locking system (40) according to the invention. [8] Tilting system (10) according to the preceding claim, wherein the ring element (1225) of the locking system (40) is arranged around an output shaft (1232) of an actuator (123) of the tilting system (10) or around a shaft (11) of the tilting system (10) to which the drive unit (20) is connected. [9] Aircraft comprising a tilting system (10) according to one of the preceding claims 7 or 8.

Images