Unmanned aerial vehicle

Abstract

The unmanned aerial vehicle provided by the invention is uniform in lift force and relatively small in overall size of the fuselage. The unmanned aerial vehicle has four propeller shafts extending horizontally from a fuselage along diagonals, and four propellers each including two blades having a folding mechanism. Rotation of the engine is transmitted to the propeller through a gear. The unmanned aerial vehicle is characterized in that all the propellers are located at the same height from the ends of the propeller shafts; the rotation range is overlapped with the rotation range of the adjacent propeller; the mounting angle is set to deviate from the mounting angle of the adjacent propeller by 90 degrees; and the rotation direction is opposite to the rotation direction of the adjacent propeller.

Description

Technical Field

[0001] The present invention relates to an unmanned aerial vehicle, and more particularly, to an unmanned aerial vehicle having a foldable propeller, wherein the foldable propeller is located at the same height as an adjacent propeller and can rotate with an overlapping rotation range. Background Art

[0002] Unmanned aerial vehicles are usually transported by, for example, loading them onto a truck and then transporting them to an airport. A 2-ton truck, for example, has a box that is 3.1 meters long, 1.6 meters wide, and 0.4 meters high. It is desirable that the size of the unmanned aerial vehicle be suitable for loading onto such a truck. If the unmanned aerial vehicle is equipped with four horizontally rotating propellers, each 1.8 meters long and arranged so as not to overlap each other, the overall size of the aircraft becomes 3.6 meters in length and width. Therefore, it is impossible to load it onto a 2-ton truck box. By making the propellers foldable, the length of each propeller can be reduced to 0.9 meters, thereby obtaining an overall size of 1.8 meters in length and width. However, it still cannot be loaded onto a 1.6-meter wide truck box.

[0003] In order to enable the UAV to be loaded onto a 2-ton truck, it is conceivable to reduce its overall size by overlapping the rotation range of the propellers. In this case, to prevent the propellers from colliding, the height of the propellers is adjusted to ensure their correct overlap. If adjacent propellers overlap by about 0.5 meters, its overall size can be reduced to 0.8 meters in length (1.8 meters - 0.5 meters × 2), making it possible to load the UAV onto a 2-ton truck bed.

[0004] When each propeller is driven by its own motor, it is effective to eliminate the collision of the propellers by creating a height difference between the propellers. However, from the perspective of uniform lift and stability of the unmanned aerial vehicle, it is not desirable to create a height difference between the propellers. In contrast, if the propellers are driven by an engine through gears, each propeller can rotate synchronously with the other propellers, maintaining a constant positional relationship. This allows the propellers to be placed at the same height without causing collisions between them. Patent document 1 (JP2020-100241A) discloses an unmanned aerial vehicle equipped with an engine, wherein its propellers are driven by gears. However, the document does not disclose folding the propellers or arranging them in an overlapping manner.

[0005] Prior art literature Patent Document 1: JP2020-100241A Summary of the invention Technical issues An object of the present invention is to provide an unmanned aerial vehicle that can achieve uniform lift and reduce the overall size of the aircraft.

[0006] Solution to the problem According to the present invention, an unmanned aerial vehicle comprises: four propeller shafts extending from a fuselage and arranged horizontally in a diagonal direction; four propellers, each of which comprises two blades having a folding mechanism; and a gear for transmitting the rotation of an engine to the propellers. The four propellers are located at the same height relative to each end of the respective corresponding propeller shafts, adjacent propellers have overlapping rotation ranges, the propellers are installed at an offset installation angle of 90° with each adjacent propeller, and the adjacent propellers rotate in opposite directions.

[0007] The folding mechanism includes a knob, a spring, a pin and a rubber damper surrounding the pin. The knob is pulled to release the engagement between the pin and the blade so that the blade rotates around the rotation axis.

[0008] Effects of the Invention The unmanned aerial vehicle of the present invention has the following technical effects: (1) By positioning all four propellers at the same height, uniform lift is achieved. (2) By providing overlapping rotation ranges for adjacent propellers and introducing a folding mechanism for each propeller, the overall size of the aircraft is reduced so that it can be loaded onto a small truck and transported on public roads. (3) By driving the propellers with gears, offsetting the installation angles of adjacent propellers by 90°, and making the rotation directions of adjacent propellers opposite, the propellers can be located at the same height and have overlapping rotation ranges without colliding with each other.

[0009] By providing the blades with a folding mechanism comprising a knob, a spring, a pin and a rubber damper around the pin, the knob can be manually pulled to release the engagement between the pin and the blade, thereby enabling the blade to rotate about the axis of rotation. This enables the propeller to fold. By providing the rubber damper on the pin, the load applied to the pin when the propeller starts to rotate can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 A plan view of an unmanned aerial vehicle of the present invention is shown with the propeller in a rotating state; Figure 2 A plan view of the unmanned aerial vehicle of the present invention is shown with the propeller in a stopped state; Figure 3 Shows Figure 2 A plan view of the unmanned aerial vehicle with its propeller folded; Figure 4 A plan view of the main bevel gear driving the four propellers is shown; Figure 5 An internal structural diagram of the mechanism driving the first and third propellers is shown; Figure 6 An internal structural diagram of the mechanism driving the second and fourth propellers is shown; Figure 7 Shows Figure 5 Detailed view of section A showing the folding mechanism of the blades. DETAILED DESCRIPTION

[0011] The unmanned aerial vehicle of the present invention is described in detail below with reference to the accompanying drawings.

[0012] Example Figure 1 The plan view of the unmanned aerial vehicle 100 of the present invention with the propeller in the rotating state is shown. The unmanned aerial vehicle 100 is equipped with four propellers 6 surrounding the fuselage 5. The four propellers 6 are the first propeller 1, the second propeller 2, the third propeller 3 and the fourth propeller 4 in clockwise order. The fuselage 5 is provided with a first propeller shaft 21, a second propeller shaft 22, a third propeller shaft 23 and a fourth propeller shaft 24, which are all arranged horizontally along the diagonal direction. The propellers 6 are mounted on a vertical shaft arranged at the end of each propeller shaft so that they can rotate horizontally. The rotation ranges of the propellers 6 are arranged to overlap each other. The rotation range of the first propeller 1 overlaps with the rotation range of the fourth propeller 4 on the left and the second propeller 2 in front. The rotation range of the second propeller 2 overlaps with the rotation range of the first propeller 1 at the rear and the third propeller 3 on the left. The rotation range of the third propeller 3 overlaps with the rotation range of the second propeller 2 on the right and the fourth propeller 4 at the rear. The rotation range of the fourth propeller 4 overlaps with the rotation ranges of the third propeller 3 in front and the first propeller 1 on the right. All four propellers 6 are arranged at the same height.

[0013] Figure 2 A plan view of an unmanned aerial vehicle with the propellers of the present invention in a stopped state is shown. Each propeller 6 consists of two blades, each of which is referred to as a blade 6a. When the propellers stop, the first propeller 1 and the third propeller 3 stop toward the left and right, while the second propeller 2 and the fourth propeller 4 stop toward the front and back. In this embodiment, the propellers 6 are rotated by a drive shaft 12 (described later) disposed behind a clutch on the engine crankshaft. Although the stop positions of the propellers are not always consistent when they stop, they can be manually rotated to a predetermined position after stopping. After the propellers stop, the drive shaft 12 can also be rotated to a predetermined position by a drive motor, without being limited to manual adjustment. The propellers 6 are installed at an offset angle of 90° to each other to prevent them from colliding.

[0014] refer to Figure 2 , the propellers 6 are installed so that the first propeller 1 and the third propeller 3 face left and right, while the second propeller 2 and the fourth propeller 4 face front and back. In this embodiment, the first propeller 1 and the third propeller 3 rotate clockwise, while the second propeller 2 and the fourth propeller 4 rotate counterclockwise. The rotation of the first propeller 1 to the fourth propeller 4 alternates between clockwise and counterclockwise: right, left, right, left. This can prevent the blades 6a from colliding with each other in the area where the propellers 6 overlap. Reference Figure 1 When the blade 6a of the first propeller 1 facing the left side in the overlap region rotates rightward and points backward, the blade 6a of the fourth propeller 4 facing forward enters the overlap region. Therefore, the blade 6a of the first propeller 1 and the blade 6a of the fourth propeller 4 do not collide.

[0015] Figure 3 Shows Figure 2 The propeller of the unmanned aerial vehicle is folded. After the engine stops, Figure 2 As shown, the blades 6a of the propeller 6 protrude from the fuselage 5 to the right and left and to the front and rear. By folding these blades inward, the overall size of the unmanned aerial vehicle can be reduced. Figure 3 In the figure, the blades 6a of the first propeller 1 and the blades 6a of the second propeller 2 are shown in an overlapping manner, and since the blades 6a are installed at a certain angle, they do not actually collide. The folding of the propeller 6 is performed by a folding mechanism 13 (described later) located at the bottom of each blade 6a.

[0016] Figure 4 A plan view of the main bevel gear 7 driving the four propellers 6 is shown. In this embodiment, the engine is a horizontal engine with the crankshaft oriented vertically. The drive shaft 12 connected to the crankshaft through a clutch is also oriented vertically. The main bevel gear 7 is mounted on the drive shaft 12. The main bevel gear 7 is meshed with the first secondary bevel gear 8, the second secondary bevel gear 9, the third secondary bevel gear 10 and the fourth secondary bevel gear 11. Each secondary bevel gear transmits the rotation of the engine to the first propeller shaft 21, the second propeller shaft 22, the third propeller shaft 23 and the fourth propeller shaft 24 respectively. From the top view, if the main bevel gear 7 rotates clockwise, the first secondary bevel gear 8, the second secondary bevel gear 9, the third secondary bevel gear 10 and the fourth secondary bevel gear 11 all rotate counterclockwise when viewed from one end.

[0017] Figure 5 The internal structure diagram of the mechanism for driving the first propeller and the third propeller is shown. The mechanism for the first propeller 1 and the mechanism for the third propeller 3 have the same structure. Figure 5As shown, the rotation of the first propeller shaft 21 is converted into reverse rotation by two bevel gears 25 and 26 and transmitted to the vertical shaft 30. Then, the rotation of the vertical shaft 30 is transmitted to the blades 6a, 6a of the first propeller 1. Figure 4 As shown, the first bevel gear 8 located at one end of the first propeller shaft 21 rotates counterclockwise, so when viewed from the left side, the first bevel gear 8 located at one end of the first propeller shaft 21 rotates counterclockwise. Figure 5 The bevel gear 25 at the other end of the first propeller shaft 21 rotates clockwise, and when viewed from below, the bevel gear 26 on the vertical shaft 30 rotates counterclockwise. Therefore, the first propeller 1 rotates clockwise when viewed from above (in a plan view).

[0018] Similarly, if Figure 5 As shown, the rotation of the third propeller shaft 23 is converted into reverse rotation by two bevel gears 25 and 26 and transmitted to the vertical shaft 30. Then, the rotation of the vertical shaft 30 is transmitted to the blades 6a, 6a of the third propeller 3. Figure 4 As shown, the third bevel gear 10 located at one end of the third propeller shaft 23 rotates counterclockwise, so when viewed from the left side, the third bevel gear 10 located at one end of the third propeller shaft 23 rotates counterclockwise. Figure 5 The bevel gear 25 at the other end of the first propeller shaft 23 rotates clockwise, and the bevel gear 26 on the vertical shaft 30 rotates counterclockwise when viewed from below. Therefore, the third propeller 3 rotates clockwise when viewed from above (in a plan view).

[0019] Figure 6 The internal structure diagram of the mechanism driving the second and fourth propellers is shown. The mechanism for the second propeller 2 and the mechanism for the fourth propeller 4 have the same structure. The rotation of the second propeller shaft 22 is converted into the same direction by two bevel gears 27 and 28 and transmitted to the vertical shaft 30. Then, the rotation of the vertical shaft 30 is transmitted to the blades 6a, 6a of the second propeller 2. Figure 4 As shown, the second bevel gear 9 located at one end of the second propeller shaft 22 rotates counterclockwise, so Figure 6 The bevel gear 27 at the other end of the second propeller shaft 22 rotates clockwise, and, when viewed from below, the bevel gear 28 on the vertical shaft 30 rotates clockwise. Therefore, the second propeller 2 rotates counterclockwise when viewed from above (in a plan view).

[0020] refer to Figure 6 The rotation of the fourth screw shaft 24 is converted into the same direction by two bevel gears 27 and 28 and transmitted to the vertical shaft 30. Then, the rotation of the vertical shaft 30 is transmitted to the blades 6a, 6a of the fourth propeller 4. Figure 4 As shown, the fourth bevel gear 11 located at one end of the fourth propeller shaft 24 rotates counterclockwise. Figure 6The bevel gear 27 at the other end of the fourth propeller shaft 24 rotates clockwise, and the bevel gear 28 on the vertical shaft 30 rotates clockwise when viewed from below. Therefore, the fourth propeller 4 rotates counterclockwise when viewed from above (in a plan view). Figure 5 and Figure 6 As shown, the vertical shafts 30 have the same length, and the first propeller 1, the second propeller 2, the third propeller 3 and the fourth propeller 4 are all at the same height relative to the ends of their respective shafts.

[0021] Figure 7 yes Figure 5 A detailed view of part A in FIG. 1 shows the folding mechanism 13 of the blade 6a. Figure 5 As shown, the folding mechanism 13 is provided at the bottom of the blade 6a. The folding mechanism 13 includes a pin 13a, a rubber damper 13b surrounding the pin 13a, a spring 13c and a knob 13d. When the knob is manually pulled, the engagement between the pin 13a and the blade 6a is released, so that the blade 6a can rotate around the rotation axis 14. This allows the blade 6a to rotate horizontally by 90 degrees. By providing the rubber damper 13b, it is possible to reduce the load applied to the pin 13a when the propeller starts to rotate.

[0022] Industrial Applicability The present invention is suitable for use in unmanned aerial vehicles because the propellers are configured to be foldable, have a rotation range that overlaps with adjacent propellers, and rotate in opposite directions. These features achieve uniform lift and reduce the overall size of the aircraft.

[0023] Description of Reference Numerals 1. First propeller 2. Second propeller 3. The third propeller 4. Fourth propeller 5. Body 6. Propeller 6a. Leaves 7. Main bevel gear 8. First bevel gear 9. Second bevel gear 10. The third bevel gear 11. The fourth bevel gear 12. Drive shaft 13. Folding mechanism 13a. Sales 13b. Rubber damper 13c. Spring 13d. Knob 14. Rotation axis 15. Propeller retainer 21. First propeller shaft 22. Second propeller shaft 23. Third propeller shaft 24. Fourth propeller shaft 25,26. Bevel gear 27,28. Bevel gear 30. Vertical axis 100. Unmanned aerial vehicles.

Claims

1. An unmanned aerial vehicle, comprising: four propeller shafts extending from the fuselage and arranged horizontally along a diagonal line; four propellers, each of which comprises two blades with a folding mechanism; and a gear that transmits the rotation of the engine to the propellers; The four propellers are located at the same height relative to each end of their respective corresponding propeller shafts, adjacent propellers have overlapping rotation ranges, each propeller is offset by 90° from the installation angle of the adjacent propeller, and the adjacent propellers rotate in opposite directions.

2. The unmanned aerial vehicle according to claim 1, characterized in that: The folding mechanism includes a knob, a spring, a pin, and a rubber damper surrounding the pin, wherein the knob is pulled to release the engagement between the pin and the blade to allow the blade to rotate about a rotation axis.

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