Passive tilting rotor mechanism for EVTOL

Abstract

The invention discloses a passive tilting rotor mechanism for an EVTOL. A main tilting shaft is designed to be fixed to a wing along a wingspan. A main motor is mounted at the end part of the main tilting rotating shaft through a main motor frame and can rotate around the main tilting rotating shaft; and the rotation angle of the main motor is 0-90 degrees by designing a limiting structure, and the rotation angle is measured by installing an angle sensor. A carbon tube is fixedly installed on the main motor frame, and tilting motors are symmetrically installed at the two ends of the carbon tube relative to the main motor and rotate along with the main motor. Meanwhile, a locking structure is further designed so that locking and fixing can be achieved when the rotating angle is 0 degree or 90 degrees. When the airplane takes off and lands vertically, the mechanism is locked in a 0-degree horizontal state, so that the thrust is vertically upward; in the process of transition to the cruise stage, the two tilting motors generate thrust difference through the rotating speed difference, the mechanism rotates around the main tilting shaft to the 90-degree vertical position to be locked, and thrust is horizontally forward. Compared with an existing mechanism enabling thrust to tilt through active control, the mechanism has the advantages of being high in response speed, simple and high in reliability.

Description

Technical Field

[0001] The present invention belongs to the technical field of aircraft design, and particularly relates to a passive tilt-rotor mechanism in an EVTOL (electric vertical takeoff and landing aircraft) based on a fixed wing. Compared with the tilt-rotor mechanism controlled actively, this mechanism has the advantages of fast response speed and high reliability, and is applicable to various scenarios such as low-altitude transportation, logistics, and emergency rescue. Background Art

[0002] With the rapid economic development, traditional transportation methods can no longer meet people's needs. The rapid development of the low-altitude economy has made how to make good use of the low-altitude area to achieve fast transportation an important direction for the development of aircraft. As a new type of transportation vehicle, EVTOL aircraft have the advantages of vertical takeoff and landing, flexibility, environmental protection and energy conservation, and are gradually becoming an important part of future urban transportation. Since the cruise efficiency of fixed-wing aircraft is higher than that of multi-rotor aircraft, fixed-wing EVTOLs are attracting more and more attention.

[0003] Currently, the common implementation method of fixed-wing EVTOL is the tilt-rotor type, that is, the power is upward during the vertical takeoff and landing stage and forward during the cruise stage. At present, most of the methods for realizing tilt-rotors are modeled after the V-22 Osprey of the United States, and the rotors are tilted through an active mechanism. However, the mechanical tilt mechanism composed of complex transmission parts has led to frequent accidents of the V-22 Osprey and limited reliability. The active tilt mechanism significantly increases the weight and structural complexity of the aircraft due to the need for additional transmission components. At the same time, the mechanical wear caused by the complex structure results in a high failure rate, reducing the system reliability and maintainability. Therefore, how to design a simple, reliable and efficient tilt mechanism has become a key issue in the design of tilt-rotor EVTOL. Summary of the Invention

[0004] To solve the problems existing in the prior art and aiming at the defects of the prior art, the present invention proposes a passive tilt-rotor mechanism for EVTOL, which realizes the passive tilt of EVTOL based on the differential speed of motors.

[0005] The passive tilt-rotor mechanism for EVTOL of the present invention includes a main motor, a first tilt motor, a second tilt motor, a locking mechanism, a main tilt shaft and a tilt motor mounting rod.

[0006] The main motor is installed on a main motor seat, and the main motor seat is installed at the end of the main tilt shaft through inner and outer clamping hoops to form a rotating pair; a first propeller is coaxially fixed on the output shaft of the main motor.

[0007] The first tilting motor and the second tilting motor are coaxially installed with propellers on their output shafts, which are fixedly installed on two tilting motor seats and are respectively fixed to the front and rear ends of the tilting motor mounting rod through clamps. The middle of the tilting motor mounting rod tightly fixes two clamps, and the two clamps are fixedly connected to the bottom of the main motor seat, so that the two tilting motors can rotate together with the main motor.

[0008] The axis of the above-mentioned connecting carbon tube is perpendicular to the main tilting axis and also perpendicular to the axis of the main motor; at the same time, the axes of the output shafts of the main motor, the first tilting motor, and the second tilting motor are parallel, and the positions of the first tilting motor and the second tilting motor are symmetrical with respect to the main motor.

[0009] The locking mechanism consists of a limiting part and a locking part. Among them, the limiting part is composed of a limiting clamp tightly fixed on the main tilting axis and an inner clamp of the main motor. The upper half of the inner clamp of the main motor protrudes inward; at the same time, the rear section of the lower half of the limiting clamp protrudes outward. Thus, during the rotation of the main motor seat, through the cooperation of the protrusions on the limiting clamp and the protrusions on the inner clamp of the main motor, the rotation of the passive tilting mechanism is limited between 0 and 90 degrees.

[0010] The locking part includes a servo motor, a servo arm and a locking pin. Among them, the servo motor is fixedly installed on the servo motor mounting clamp tightly fixed on the main tilting axis through a servo motor frame. The output shaft of the servo motor is arranged parallel to the output shaft of the main motor, and is fixedly connected to the end of the servo arm. The front end of the locking pin is inserted into the through hole A opened in the front of the upper half of the servo motor mounting clamp, and at the same time, a through hole B of the same size is opened in the front of the upper half of the limiting clamp, and through holes C and D of the same size are opened in the front and rear of the upper half of the inner clamp of the main motor; the through hole A and the through hole B are coaxial, and at the same time, when the passive tilting rotor mechanism is at 0 degrees, the through hole A, the through hole B and the through hole C are symmetrically arranged, and when the passive tilting rotor mechanism is at 90 degrees, the through hole A, the through hole B and the through hole D are coaxial.

[0011] The end of the above-mentioned locking pin is designed with a driving rod perpendicular to the axial direction of the locking pin, and the driving rod is inserted into the chute opened along the axial direction of the servo arm at the front part of the servo arm. Thus, through the drive of the servo motor, the servo arm drives the locking pin to move linearly along the axis of the through hole A, and further, when the passive tilting rotor mechanism is at 0 degrees and 90 degrees, the locking pin is inserted into the corresponding through holes on the limiting clamp and the inner protection of the main motor to lock the main motor seat.

[0012] The advantages of the present invention are as follows:

[0013] 1. Compared with the tilting mechanism controlled by the active mechanism, the passive tilting rotor mechanism of the present invention reduces the complexity of the mechanism, thereby increasing the reliability and flight safety.

[0014] 2. At the same time, this passive tilt-rotor mechanism improves the rapidity, enables a faster transition from the multi-rotor takeoff and landing mode to the fixed-wing cruise mode, reduces the transition time, and decreases the accident rate during the transition process, further enhancing flight safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the overall structure of the passive tilt-rotor mechanism of the present invention;

[0016] Figure 2 Schematic diagram of the installation method of the angle sensor in the passive tilt-rotor mechanism of the present invention;

[0017] Figure 3 Schematic diagram of the first hoop structure in the passive tilt-rotor mechanism of the present invention;

[0018] Figure 4 Schematic diagram of the seventh hoop structure in the passive tilt-rotor mechanism of the present invention;

[0019] Figure 5 Schematic diagram of the locking mechanism structure in the passive tilt-rotor mechanism of the present invention;

[0020] Figure 6 Schematic diagram when the passive tilt-rotor mechanism of the present invention is in the 90° state.

[0021] In the figure:

[0022] 1 - Main motor 2 - First propeller 3 - First tilt motor

[0023] 4 - Second tilt motor 5 - Second propeller 6 - Angle sensor

[0024] 7 - Locking mechanism 8 - Main tilt shaft 9 - Tilt motor mounting rod

[0025] 10 - Intermediate plate 11 - Main motor base 12 - Tilt motor base

[0026] 13 - First hoop 14 - Second hoop 15 - Third hoop

[0027] 16 - Fourth hoop 17 - Fifth hoop 18 - Sixth hoop

[0028] 19 - Connecting carbon sheet 20 - Sleeve 21 - Seventh hoop

[0029] 22 - Servo 23 - Servo arm 24 - Locking pin

[0030] 25 - Eighth hoop 26 - Through hole A 27 - Through hole B

[0031] 28 - Through hole C 29 - Through hole D DETAILED DESCRIPTION OF THE INVENTION

[0032] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0033] The passive tilt-rotor mechanism of the present invention for EVTOL is as Figure 1 shown, and includes a main motor 1, a first propeller 2, a first tilt motor 3, a second tilt motor 4, a second propeller 5, an angle sensor 6, a locking mechanism 7, a main tilt axis 8, a tilt motor mounting rod 9 and an intermediate plate 10.

[0034] The end of the main motor 1 is fixedly installed on the top surface of the main motor base 11, and its front output shaft is coaxially fixedly installed with a first propeller 2. The first propeller 2 is a two-blade large-size propeller, which is used to provide the main power for the vertical takeoff and landing and cruise stages of the aircraft.

[0035] The inner and outer sides of the bottom surface of the main motor base 11 are respectively fixedly connected to the upper halves of the first clamp 13 and the second clamp 14 by bolts. The upper halves of the first clamp 13 and the second clamp 14 are respectively matched with the lower halves of the first clamp 13 and the second clamp 14 to clamp and fix the main motor base 11 on two bearings installed at the end of the main tilt axis 8; so that the entire main motor base 10 together with the main motor 1 can rotate around the main tilt axis 8.

[0036] The ends of the first tilt motor 3 and the second tilt motor 4 are respectively fixedly installed on two tilt motor bases 12. The two tilt motor bases 12 are respectively fixedly installed on the upper halves of the third clamp 15 and the fourth clamp 16 by bolts. The upper halves of the third clamp 15 and the fourth clamp 16 are respectively matched with the lower halves of the third clamp 15 and the fourth clamp 16 to clamp and fix the first tilt motor 3 and the second tilt motor 4 at both ends of the tilt motor mounting rod 9. The tilt motor mounting rod 9 is made of a carbon tube, and a fifth clamp 17 and a sixth clamp 18 are clamped and fixed in the middle. The upper halves of the fifth clamp 17 and the sixth clamp 18 are respectively fixedly installed on the front and rear sides of the bottom surface of the intermediate plate 10 by bolts. Further, the inner and outer sides of the top surface of the intermediate plate 10 are fixed on the lower halves of the first clamp 13 and the second clamp 14. Thus, a passive tilt-rotor mechanism is formed. In this mechanism, the axis of the tilt motor mounting rod 9 is perpendicular to the main tilt axis 8 and also perpendicular to the axis of the main motor 1; at the same time, the axes of the output shafts of the main motor 1, the first tilt motor 2, and the second tilt motor 3 are parallel, and the first tilt motor 2 and the second tilt motor 3 are symmetrically located relative to the main motor 1.

[0037] The output shafts of the above-mentioned first tilt motor 2 and the second tilt motor 3 are coaxially installed with three-blade small-size propellers, and the power is less than that of the main motor; the size of the propeller blades is specifically selected according to the required thrust, so that the thrust ratio generated by the large propeller and the small propeller during the vertical takeoff and landing stage is 6:4. Furthermore, a torque is generated by the differential speed of the first tilt motor 2 and the second tilt motor 3, so that the main motor 1 rotates around the main tilt axis 8.

[0038] The passive tilt-rotor mechanism of the present invention is different from the existing actively controlled tilt mechanisms. The current tilt angle of the passive tilt-rotor mechanism is unknown. Therefore, an angle sensor 6 is installed on the passive tilt-rotor mechanism to measure the tilt angle of the current passive tilt-rotor mechanism in real time, so as to better control the flight during the tilting process.

[0039] The angle sensor 6 has an external cylindrical part and an internal rotating shaft part. The two parts can rotate relative to each other, and the relative rotation angle between the two parts can be measured. As Figure 2 shown, the external cylindrical part of the angle sensor 6 is fixedly connected to the center position of the front surface of the connecting carbon sheet 19 by screws; the connecting carbon sheet 19 is fixedly connected to the second hoop 14 near the end of the main tilt shaft 8 by bolts, so that the external cylindrical part can rotate together with the main motor 1.

[0040] The internal rotating shaft part of the angle sensor 6 is coaxially fixedly installed with a sleeve 20 by 502 glue. The sleeve 20 is coaxially fixed inside the main tilt shaft 4 and fixed by a pin. Thus, the inside of the angle sensor 6 is fixed and the outside rotates, so that the rotation angle of the passive tilt-rotor mechanism can be measured.

[0041] To improve the reliability of the passive tilt-rotor mechanism during the vertical takeoff and landing stage and the cruise stage, a locking mechanism 7 is added to it. The locking mechanism 7 consists of a limiting part and a locking part. Among them, the limiting part is realized by the cooperation of the seventh hoop 21 and the first hoop 13. Specifically:

[0042] As Figure 3 、 Figure 4 shown, the thickness of the upper half of the first hoop 13 is designed to be greater than that of the lower half. When it is clamped with the main tilt shaft 8, the outer sides of the upper half and the lower half of the first hoop 3 are flush, so that the upper half of the hoop 3 has a convex part protruding inward relative to its lower half. The seventh hoop 21 is clamped and fixed on the main tilt shaft 8 through the cooperation of its upper half and lower half. The thickness of the rear half of the lower half of the seventh hoop 21 is greater than that of the rest of the position. When it is clamped and fixed with the main tilt shaft 8, the inner sides of the upper half and the lower half of the seventh hoop 21 are flush, so that the rear half of the lower half of the seventh hoop 21 has a convex part protruding inward, and the outer side of the convex part is attached to the inner side of the lower half of the first hoop 13. Thus, since the seventh hoop 21 is fixedly clamped on the main tilt shaft 8 and does not move, during the rotation of the passive tilt-rotor mechanism around the main tilt shaft 8, through the cooperation of the convex part on the outside of the seventh hoop 21 and the convex part on the inside of the first hoop, the rotation of the passive tilt mechanism can be limited between 0 and 90 degrees. Specifically:

[0043] When the passive tilting mechanism is at 90°, the axes of the three propellers are perpendicular to the fuselage cross-section, and the front half of the protruding part of the upper half of the first hoop 13 contacts and limits the protruding part of the lower half of the seventh hoop 21, as shown in Figure 6 shown. When the passive tilt-rotor mechanism is at 0°, the axes of the three propellers are parallel to the fuselage cross-section. At this time, the rear half of the protruding part of the upper half of the first hoop 13 contacts and limits the protruding part of the lower half of the seventh hoop 21.

[0044] The locking part consists of a servo 22, a servo arm 23 and a locking pin 24, as shown in Figure 5 shown. Among them, the servo 22 is installed on the servo frame, and the servo frame is fixedly installed on the side wall of the upper half of the eighth hoop 25. The eighth hoop 25 is clamped and fixed to the main rotating shaft 8 through its upper half and lower half. The output shaft of the servo 22 is arranged parallel to the output shaft of the main motor 1 and is fixedly connected to the end of the servo arm 23. The front end of the locking pin 24 is inserted into the through hole A26 opened in the front of the upper half of the eighth hoop 25. At the same time, through holes B27 of the same size are opened in the front of the upper half of the seventh hoop 21, and through holes C28 and D29 of the same size are opened in the front and rear of the upper half of the first hoop 13. The above-mentioned through hole A26 and through hole B27 are coaxial. At the same time, when the passive tilt-rotor mechanism is at 0°, the positions of through hole A26, through hole B27 and through hole C28 are symmetrical. When the passive tilt-rotor mechanism is at 90°, through hole A26, through hole B27 and through hole D29 are coaxial.

[0045] A driving rod perpendicular to the axial direction of the locking pin 24 is designed at the end of the above-mentioned locking pin 24, and the driving rod is inserted into the chute opened along the axial direction of the servo arm 23 in the front part of the servo arm 23. Thus, the servo 22 drives the servo arm 23 to rotate around the output shaft of the servo 22, and then the locking pin 24 can be translated along the axis of the through hole A26 under the drive of the servo arm 23. Furthermore, when the passive tilt-rotor mechanism is at 0° and 90°, the translation of the locking pin 24 enables it to be inserted into the corresponding through holes on the seventh hoop 21 and the eighth hoop 25, thereby locking the first hoop 13 and making the passive tilt-rotor mechanism unable to rotate around the main tilting shaft 8. A chamfer is designed at the front end of the above-mentioned locking pin 24 so that the front end of the locking pin 24 can still be inserted into each through hole even when there is a slight angle error.

[0046] In order to facilitate the production and processing of the passive tilt-rotor mechanism, the connection between components and the realization of the limiting part, all hoops in the present invention are designed as square hoops. Specifically: the upper half and the lower half of the hoop are rectangular structures of the same size, and semi-circular notches are opened in the middle of the opposite sides; after the upper half and the lower half are fixed, the whole is a square with a circular hole in the middle.

[0047] The passive tilt-rotor mechanism of the present invention is installed on both sides of the wings of the aircraft through the main tilt axis 8, and the main tilt axis 8 is arranged along the wingspan and fixed inside the wing. During the vertical takeoff and landing process of the aircraft, the passive tilt-rotor mechanism is locked at the 0-degree position by the locking mechanism 7, so that the thrust is vertically upward; when the aircraft transitions from the vertical takeoff and landing stage to the fixed-wing cruise stage, the control servo 22 drives the servo arm 23 to pull the locking pin 24 inward, so that the passive tilt-rotor mechanism is disengaged from the locked state, and then the passive tilt-rotor mechanism rotates around the main tilt axis 8 through the speed difference between the first tilt motor 2 and the second tilt motor 3; when the aircraft reaches the fixed-wing cruise stage, the passive tilt-rotor mechanism is at the 90-degree position, and at this time the control servo 22 drives the servo arm 23 to push the locking pin 24 inward to lock the passive tilt-rotor mechanism, so that the thrust is horizontally forward.

Claims

1. A passive tilt-rotor mechanism for EVTOL, characterized by: It includes a main motor, a first tilt motor, a second tilt motor, a locking mechanism, a main tilt axis and a tilt motor mounting rod; The main motor is installed on the main motor seat, and the main motor seat is installed on the end of the main tilt shaft through inner and outer clamps to form a rotation pair; the first propeller is coaxially fixed on the output shaft of the main motor; The propellers are coaxially mounted on the output shafts of the first tilt motor and the second tilt motor, fixedly mounted on the two tilt motor seats, and respectively fixed to the front and rear ends of the tilt motor mounting rod through clamps; two clamps are clamped and fixed in the middle of the tilt motor mounting rod and are fixedly connected to the bottom of the main motor seat through the two clamps; The axis of the connecting carbon tube is perpendicular to the main tilt axis and the axis of the main motor; the output axes of the main motor, the first tilt motor and the second tilt motor are parallel, and the first tilt motor and the second tilt motor are symmetrical relative to the main motor; The locking mechanism is composed of a limiting part and a locking part; wherein the limiting part is composed of a limiting clamp fixed on the main tilt shaft and an inner clamp of the main motor; wherein the upper half of the inner clamp of the main motor protrudes inward; and at the same time, the rear section of the lower half of the limiting clamp protrudes outward, so that during the rotation of the main motor seat, the rotation of the passive tilt mechanism is limited between 0 and 90 degrees by the cooperation of the protrusion on the limiting clamp and the protrusion on the inner clamp of the main motor; The locking part includes a servo, a servo arm and a locking pin; wherein the servo is fixedly mounted on the servo mounting clamp fixed on the main tilt shaft through a servo frame; the servo output shaft is arranged parallel to the main motor output shaft, and is connected and fixed to the end of the servo arm; the front end of the locking pin is inserted into a through hole A opened in the front of the upper half of the servo mounting clamp, and at the same time, a through hole B of equal size is opened in the front of the upper half of the limit clamp, and a through hole C and a through hole D of equal size are opened in the front and rear of the upper half of the clamp on the inner side of the main motor; the through hole A is coaxial with the through hole B, and when the passive tilt-rotor mechanism is at 0 degrees, the through hole A, the through hole B and the through hole C are symmetrically positioned, and when the passive tilt-rotor mechanism is at 90 degrees, the through hole A, the through hole B and the through hole D are coaxial; The end of the locking pin is designed with a driving rod perpendicular to the axial direction of the locking pin, and the driving rod is inserted into a slide groove opened along the axial direction of the servo arm at the front part of the servo arm; thereby, the servo arm drives the locking pin to move horizontally along the axis of the through hole A through the servo drive, and then when the passive tilt-rotor mechanism is at 0 degrees and 90 degrees, the locking pin is inserted into the corresponding through hole on the limit clamp and the inner side protection of the main motor to realize the locking of the main motor seat.

2. A passive tilt-rotor mechanism for EVTOL according to claim 1, characterized in that: The propellers installed on the output shafts of the first tilt motor and the second tilt motor are smaller in size than the propeller installed on the output shaft of the main motor.

3. A passive tilt-rotor mechanism for EVTOL according to claim 1, characterized in that: It also has an angle sensor; the outer cylindrical part of the angle sensor is fixed to the outer clamp of the main motor through a mounting plate; the inner shaft part of the angle sensor 6 is coaxially fixed with a mounting sleeve, and the sleeve is coaxially fixed in the main tilt shaft.

4. A passive tilt-rotor mechanism for EVTOL according to claim 1, characterized in that: The upper and lower halves of the limit clamp and the inner clamp of the main motor are rectangular structures of equal size, with a semicircular notch in the middle of the opposite side; after the upper and lower halves are fixed, the whole is a square with a circular hole in the middle.

5. A passive tilt-rotor mechanism for EVTOL according to claim 1, characterized in that: During the vertical take-off and landing process of the aircraft, the passive tilt-rotor mechanism is locked at the 0 degree position by the locking mechanism, so that the thrust is vertically upward; when the aircraft transitions from the vertical take-off and landing stage to the fixed-wing cruise stage, the control servo drives the servo arm to pull the locking pin inward to make the passive tilt-rotor mechanism out of the locked state, and then the passive tilt-rotor mechanism is rotated around the main tilt axis through the speed difference between the first tilt motor and the second tilt motor; when the aircraft reaches the fixed-wing cruise stage, the passive tilt-rotor mechanism is at a 90 degree position. At this time, the control servo drives the servo arm to push the locking pin inward to lock the passive tilt-rotor mechanism, so that the thrust is horizontally forward.

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