JP2024077003A - Propeller blades, propeller mechanisms and flying objects - Google Patents

Abstract

[Problem] The problem is to provide a propeller blade, a propeller mechanism, and a flying object with improved propeller efficiency. [Solution] A propeller blade 3 for use in a flying object 20, the blade 3 is composed of an inner blade 4 on the propeller shaft 2 side and an outer blade 5 provided on the outside of the inner blade, the blade angles 23 formed by the inner blade and the outer blade with the propeller rotation surface 22 are each variable, and a suppression mechanism 6 is provided near the adjacent portion of the outer blade and the inner blade, and the suppression mechanism suppresses the airflow 30 that passes between the outer blade and the inner blade and wraps around from the lower surface of the outer blade to the upper surface. [Selected Figure] Figure 1

Description

The present invention relates to a propeller blade, a propeller mechanism, and a flying object. More specifically, the present invention relates to a propeller blade, a propeller mechanism, and a flying object with a variable blade angle.

Winglets are provided at the tips of the propeller blades to prevent airflow from flowing around the upper surface based on the pressure difference between the upper and lower surfaces of the propeller blade.
For example, Patent Document 1 discloses a helicopter blade body with erected wing tips (see FIG. 6 of Patent Document 1).

Propeller aircraft use controllable pitch propellers that change the angle of the entire propeller blade depending on the speed in order to maintain an appropriate blade angle from the speed close to zero at takeoff to the high speed range during level flight.
For example, Patent Document 2 discloses the structure of a controllable pitch propeller used in a lightweight aircraft.

JP 2018-184079 A JP 2007-50869 A

In recent years, with the increasing demand for vertical take-off aircraft, there is a demand for propellers that can maintain high propeller efficiency over a wide range of speeds, from low to high.
For example, the applicant has invented a propeller mechanism that divides the propeller blades into inner and outer blades and changes the blade angle of each blade. At the dividing point between the inner and outer blades, there is a risk that an airflow due to the pressure difference from the bottom to the top may occur. This airflow may reduce the lift of the blades and reduce the propeller efficiency.

The present invention aims to provide a propeller blade, a propeller mechanism, and a flying object that improves propeller efficiency.

(1) The propeller blade of the present invention is a propeller blade used on a flying object, and is composed of an inner blade and an outer blade provided on the outside of the inner blade, the blade angles of the inner blade and the outer blade with the propeller rotation plane are each variable, and a suppression mechanism is provided near the adjacent portion of the outer blade and the inner blade, and the suppression mechanism suppresses the airflow that flows around from the lower surface of the outer blade to the upper surface thereof through the vicinity of the inner end surface of the outer blade.

(2) In such a propeller, the suppression mechanism is provided between the inner blade and the outer blade, and is a deformable member that changes shape in response to changes in the blade angles of the inner blade and the outer blade, and it is preferable that the deformable member deforms in response to changes in the blade angle so as to make the upper and lower surfaces of the inner blade and the outer blade approximately continuous.

(3) It is also preferable that the deformable member comprises a retaining member and a tubular member that is arranged around the retaining member and that deforms in response to changes in the blade angles of the inner blade and the outer blade.

(4) The propeller mechanism of the present invention is characterized in that it includes the propeller blades described above and an angle changing mechanism for changing the blade angles of the inner and outer blades.

(5) Another aspect of the propeller mechanism of the present invention is characterized in that it comprises a shaft that extends in a direction approximately perpendicular to the propeller axis and is rotatable around its own axis, a blade through which the shaft passes from its inner end to near its outer end, and an angle change mechanism that changes the blade angle of the blade, the tip of the shaft being fixed inside near the outer end of the blade and the base end of the shaft protruding inward from the inner end of the blade, and the blade angle is changed by twisting the inner end and outer end of the blade in opposite directions via the shaft using the angle change mechanism.

(6) The flying object of the present invention is characterized in that it is equipped with the above-mentioned propeller mechanism and a main body that flies by means of the propeller mechanism.

(7) Furthermore, it is preferable that the suppression mechanism of the propeller blade is a plate-like member that protrudes from at least one side of the outer blade, and that the plate-like member extends in the approximate width direction of the blade.

(8) It is further preferable that the plate-like member protrudes toward the upper surface side of the outer blade, and the plate surface of the plate-like member faces rearward and inward in the width direction.

The propeller blades, propeller mechanism and flying object of the present invention can increase the efficiency of the propeller.

FIG. 1a is a schematic diagram showing an example of a propeller blade of the present invention, and FIG. 1b is a plan view showing a hypothetical state in which the propeller blade of FIG. 1a is not rotating. FIG. 2a is a schematic diagram showing an example of the flying body of the present invention, and FIG. 2b is a schematic diagram showing an example of the propeller mechanism of the present invention. FIG. 3a is a vector diagram showing vector components acting on a portion of the wing at a specific length position in the longitudinal direction of the wing, and FIG. 3b is a schematic diagram for facilitating understanding of the vector direction. FIG. 4 is a schematic diagram showing the state of the inner and outer blades in a state such as hovering and the state of the inner and outer blades in a state of horizontal flight. FIG. 5a is a schematic plan view showing an example of a suppression member, and FIG. 5b is a schematic side view of FIG. 5a. FIG. 6a is a schematic diagram showing a modification of the suppression member of FIG. 5a, FIG. 6b is a schematic diagram showing another modification, and FIG. 6c is a schematic diagram showing yet another modification. FIG. 6 is a schematic diagram showing a modification of the restraining member of FIG. 5a. FIG. 8a is a schematic diagram showing another modified example of the suppression member of FIG. 5a, and FIG. 8b is a schematic diagram showing the state near the communication portion from the rear of the blade of FIG. 8a. FIG. 9a is a schematic diagram showing an example of another embodiment of the blade, and FIG. 9b is a schematic diagram showing a modified example of the suppression member of FIG. 9a. FIG. 10 is a schematic diagram showing another modification of the suppression member of FIG. 9a. FIG. 11 is a schematic plan view showing a modification of the deformable member 25 of FIG. 9a. FIG. 12 is a schematic diagram showing an example of another embodiment of the blade. 13a is a schematic cross-sectional view of another embodiment of the propeller mechanism 1, FIG. 13b is a cross-sectional view showing the rod in an exploded state, and FIG. 13c is a cross-sectional view showing the rod in an assembled state.

[1. Overview]
(Flying object 20)
First, the flying object of the present invention will be described with reference to Fig. 2a. The flying object 20 shown in the figure is composed of a main body 20a and a propeller mechanism 1 (see Fig. 2b) of the present invention provided on the main body 20a. The propeller mechanism 1 includes a propeller blade 3 of the present invention (hereinafter referred to as a blade) and an angle changing mechanism 13 that changes the angle of the blade 3.
The flying object 20 has a pair of main wings 21, 21 of approximately the same shape at the front and rear of the main body. Each main wing 21 is provided with two propeller mechanisms 1 of the present invention. In total, four propeller mechanisms 1 are provided. During takeoff and landing, the flying object 20 erects the main wings 21 and obtains buoyancy through the reaction of the force of the propeller blades 3 pushing air downward, just like a helicopter. On the other hand, during horizontal flight after takeoff, the main wings 21 are rotated to be approximately horizontal, just like a fixed-wing aircraft. Then, the altitude is maintained by utilizing the lift generated by the main wings 21. FIG. 2a shows the flying object 20 flying horizontally.

In the following explanation, the forward/backward, up/down, and left/right directions are indicated by arrows in the figures. Note that the forward/backward directions are the flight direction of the flying object 20 when it is flying horizontally.

[2. Blade angle]
(Blade angle 23, forward sweep angle 17, angle of attack 18)
3a is a schematic diagram showing vector components generated at a blade portion at a position of length r (see FIG. 3b) in the longitudinal direction from the center of rotation of the blade 3 (see symbol O in FIG. 3b). As shown in the figure, if the number of revolutions of the propeller shaft 2 is n, the blade portion 3a rotates around the propeller shaft 2 (see FIG. 2b) at a speed of 2πrn and advances at a forward speed V in the flight direction perpendicular to the rotation plane 22. Symbol Vr in the figure indicates a resultant vector of the forward speed vector V and the rotation speed vector 2πrn. The angle between the resultant vector Vr and the propeller rotation plane 22 is called the forward sweep angle 17. The blade portion 3a is further inclined by an attack angle 18 from the forward sweep angle 17, and these angles are added together to form the blade angle 23. That is, the blade angle 23 = the forward sweep angle 17 + the attack angle 18. As shown in FIG. 3b, the airflow enters the blade portion 3a in the direction of the resultant vector Vr and from the opposite direction to the resultant vector Vr.

Returning to Figure 3a, the blade portion 3a receives an air reaction force equal to the angle of attack 18. As with the main wing of a typical airplane, thrust is maximized when the angle of attack 18 is a certain value. In other words, if the forward sweep angle 18 can be calculated for the blade portion 3a at a distance r from the center O, and the blade angle 23 can be set according to the calculated forward sweep angle 18, a blade shape with high propulsion efficiency can be obtained.

[3. Configuration of the blade]
<First embodiment of blade>
(Feather 3)
Returning to Fig. 2b, the blades will be described. The blades 3 shown in Fig. 2b extend in a direction substantially perpendicular to the propeller shaft 2, i.e., in the radial direction of the rotation plane 22 (see Figs. 2a and 3a) on which the propeller rotates. The blades 3 are made up of an inner blade 4 provided on the radially inner side, an outer blade 5 adjacent to the outer side of the inner blade, and a suppression mechanism 6 provided in the vicinity 15 (see the two-dot chain line in the figure) of the adjacent portions of the inner blade 4 and the outer blade 5. The blade angles 23 (see Fig. 3a) of the inner blade 4 and the outer blade 5 are made variable by an angle changing mechanism 13.
In this embodiment, the blade 3 is divided into an inner blade 4 and an outer blade 5 near the midpoint in the longitudinal direction.
In addition, the upwardly convex curved surface of each of the blades 3, the inner blade 4 and the outer blade 5 is designated as the upper surface by the subscript a, and the other relatively flat surface is designated as the lower surface by the subscript b.

(Inner feather 4)
A through hole 4c is formed in the inner blade 4, penetrating in the direction in which the inner blade extends (longitudinal direction). A shaft 7 passes through the through hole 4c. The rotation of the propeller shaft 2 is transmitted to the inner blade 4 via the shaft 4. The inner blade 4 is supported by the shaft 7 and is rotatable about the shaft 7.

(Outer feather 5)
The tip of the shaft 7 is connected to the inner end of the outer blade 5. The rotation of the propeller shaft 2 is transmitted to the outer blade 5 via the shaft 7.

(Change in blade angle)
For example, a rotor (blade) such as an aircraft propeller receives wind at an angle that is the combination of the forward speed of the aircraft and the speed of the rotating blade (see the airflow in Figure 3b). Even if the rotor rotates at the same speed, the rotational speed of the blade changes depending on the radius, so the angle of the airflow flowing in is different between the root side and the tip side of the blade.
In order to optimize this angle difference, the blade 3 of the present invention is divided into an inner blade 4 and an outer blade 5. By changing the angles of the inner blade 4 and the outer blade 5, the angles of the inflowing airflows are effectively adjusted.

(Appearance of wing 3 during takeoff/level flight)
Figure 4 shows the state of the wing 3 when the flying body 20 (see Figure 2a) takes off, lands or hoveres vertically (state S1), and the state of the wing 3 when flying horizontally from state S1 (state S2).
In state S1, the main wing 21 is held almost vertically, and the propeller shaft 2 is aligned almost parallel to the vertical direction (not shown).
In state S2, the main wings 21 of the flying object 20 are substantially parallel to the direction of travel, which is the same as the state of the main wings in FIG.

(Wraparound airflow 30, 30a)
The blade 3 shown in Fig. 1b is in a state (S2) for horizontal flight. Fig. 1b shows a virtual state in which the blade 3 is not rotating. In the blade 3 in horizontal flight, the outer blade 5 is set to an outer blade angle β (see Fig. 4) so as to stand in the forward direction, and the inner blade 4 is set to an inner blade angle α (<β). Therefore, there is a large difference between the blade angles α and β (see Fig. 3) of the inner blade 4 and the outer blade 5. Due to this difference, a communication part S is generated between the inner blade 4 and the outer blade 5. This communication part S connects the upper surface 5a and the lower surface 5b of the outer blade 5.

Here, the upper surface of the blade 3 where lift is generated is in a state of lower pressure than the lower surface. In contrast, the lower surface is maintained at atmospheric pressure or higher, and is in a state of higher pressure than the upper surface 5a. And near the inner end surface 5c of the outer blade 5 (communication part S), a flow (air flow that will go around) 30a is generated in which air is sucked up from the high-pressure lower surface 5b of the outer blade 5 toward the low-pressure upper surface 5a (see imaginary line).

Next, Figure 1a shows the state in which the blades 3 are rotating. In reality, the blades 3 are rotating at high speed, so the end face 5c side of the airflow 30a that would wrap around as mentioned above is dragged backward. As a result, the outer blades 5 are subjected to an airflow (wraparound airflow) 30 that flows diagonally downward and to the right as shown in Figure 1a.

(Decrease in propeller efficiency)
The wraparound airflow 30 may reduce the pressure on the lower surface 5 b near the inner end of the outer blade 5 , thereby reducing the lift of the blade 3 .
In addition, there is a risk of a vortex similar to a wingtip vortex being generated behind the outer blade 5. The vortex may cause induced resistance that acts as a resistance to the forward movement of the blade 3.
Therefore, there is a risk that the wraparound airflow 30 will reduce the efficiency of the propeller. To prevent this, a suppression mechanism 6 is provided at the adjacent portion 15 of the inner blade 4 and the outer blade 5 in order to suppress the wraparound airflow 30.

(Suppression Mechanism 6)
The suppression mechanism 6 is a plate-like member provided so as to protrude from the upper surface 5a of the outer blade 5. Fig. 5a is a plan view showing the vicinity of the adjacent portion 15 of the blade 3. At the adjacent portion 15 shown in Fig. 5a, a plate-like member 6 is provided on the inner edge of the outer blade 5. The plate-like member 6 extends in the width direction (front-rear direction) of the outer blade 5. In this embodiment, for example, the length is from the vicinity of the middle of the width direction of the outer blade 5 to the rear end. The plate-like member 6 prevents the wraparound airflow 30 from flowing into the upper surface 5a of the outer blade 5. This prevents the efficiency of the propeller from decreasing.
The plate-like member 6 may be extended forward of the outer blade 5. Furthermore, the plate-like member 6 may be extended to the front end of the outer blade 5.

The plate-like member 6 has a shape similar to the cross-sectional shape of a flat-bottom wing in a plan view. That is, the curved surface 6a on the outside (left side of the figure) of the plate-like member 6 is curved convexly outward from the front side to the center, and extends rearward and inward (diagonally downward and rightward in the figure) from the center to the rear side.
Fig. 5b is a schematic side view of the plate member of Fig. 5a. As shown in Fig. 5b, the plate member 6 has a front inclined portion 6b that protrudes high from the front to the center, and a rear inclined portion 6c that becomes lower from the front inclined portion 6b to the rear.

(Suppression Airflow 31)
The rotation of the blades 3 causes an airflow 31 (hereinafter referred to as a suppressed airflow) to flow inward along the curved surface 6a at an angle 6d with respect to the front-rear direction.
1a, the suppression airflow 31 almost collides with the airflow 30a that turns around the upper surface 5a. This weakens the turning airflow 30, and prevents a decrease in the efficiency of the propeller.

[4. Other Configurations]
Next, a mechanism for rotating the blade 3 and a mechanism for changing the blade angle will be described.

(Propeller shaft 2)
2b, the propeller shaft 2 is rotated by a rotary drive mechanism 19 (see dashed double-dashed line). The rotary drive mechanism 19 may be, for example, a turboshaft engine or an electric motor.

(Propeller shaft 2 and its surrounding mechanisms)
The configuration around the propeller shaft 2 will now be described. A hub 1b is connected near the tip of the propeller shaft 2, and one or more blades 3 extend outward from the hub 1b. The base end of a shaft 7 is connected to the hub 1b so as to be rotatable about its axis, and the tip side extends in a direction perpendicular to the propeller shaft 2. The hub 1b and the surrounding area are covered with a propeller cover 1c (see FIG. 3b). The hub 1b and the blades 3 constitute the propeller 1a.

(Angle changing mechanism 13)
The angle change mechanism 13 is made up of a drive mechanism 13a that generates a drive force, and a transmission mechanism 13b that transmits the drive force as a force for changing the angle.
Specifically, the angle change mechanism 13 includes, for example, a cylinder mechanism 8 as a drive mechanism 13a, and a rotating slider 9 that moves up and down by the stroke of a cylinder rod 8a of the cylinder mechanism, and an inner rod 10 and an outer rod 11 that transmit the up and down movement of the rotating slider 9 as a transmission mechanism 13b.
The inner rod 10 and the outer rod 11 are conventionally known push-pull rods capable of transmitting a pushing and pulling force in the axial direction.
The angle change mechanism 13 may be a mechanism using a rotational power such as a motor. In this case, a gear mechanism may be provided at the connection between the inner blade 4 and the outer blade 5, and the angle between the inner blade 4 and the outer blade 5 may be optimally changed by setting a gear ratio so that when one blade is rotated by a predetermined amount, the other blade rotates by an appropriate amount. The rotational power of the gear mechanism may be hydraulic, electric, or the like.

(Cylinder mechanism 8)
The cylinder mechanism 8 includes, for example, a servo motor (not shown) capable of controlling the number of revolutions. By driving the servo motor, the cylinder mechanism 8 controls the stroke amount of a cylinder rod 8a. The tip of the cylinder rod 8a is connected to a rotary slider 9.
The tip of the cylinder rod 8a may be rotatably connected to the rotary slider 9 using a ball joint or the like.

(Rotary slider 9)
The propeller shaft 2 passes through a central hole 9a formed in the center of the rotary slider 9. The rotary slider 9 moves up and down along the propeller shaft 2.

The inner blade 4, outer blade 5, angle change mechanism 13, shaft 7, cylinder mechanism 8 and rotating slider 9 rotate together with the propeller shaft 2.

(Inner rod 10, outer rod 11, link 12)
The inner rod 10 and the outer rod 11 transmit power for changing the blade angle to the inner blade 4 and the outer blade 5, respectively. The base ends (the lower ends in the figure) of the inner rod 10 and the outer rod 11 are each connected to the rotating slider 9. The connecting parts of each rod are freely rotatable around an axis parallel to the extension direction of the shaft 7.
The tip of the inner rod 10 (the upper end in the figure) is connected to the inner end surface of the inner blade 4. The connection portion of the inner rod 10 is freely rotatable around an axis parallel to the direction in which the shaft 7 extends.
One end of the link 12 is connected to the shaft 7 between the inner blade 4 and the propeller shaft 2 and is integrated therewith.
The tip of the outer rod 11 (the upper end in the figure) is connected to the other end of the link 12. The connecting portion of the outer rod 11 is rotatable about an axis parallel to the extending direction of the shaft 7. Therefore, when the outer rod 11 moves up and down, the shaft 7 rotates via the link 12. The link 12 is attached to the thinner side of the inner blade 4 (hereinafter referred to as the rear side) with respect to the shaft 7.

(Amount of rotation of the inner blade 4 and the outer blade 5)
In this embodiment, the rotation amount of two blades, the inner blade 4 and the outer blade 5, is changed by the vertical movement of one cylinder rod 8a.
For this reason, the amount of rotation of the inner blade 4 and the amount of rotation of the outer blade 5 are adjusted so that they are approximately theoretically calculated values or approach the calculated values. Specifically, the adjustment is performed by changing the length of the link 12, the stroke amount of the cylinder rod 8a, and the distance between the connecting part of the inner rod 10 of the inner blade 4 and the shaft 7.

(Inner blade angle α, outer blade angle β)
In this embodiment, the forward sweep angle 17 of each of the inner blade 4 and the outer blade 5 is calculated from the rotation speed 2πrn (see FIG. 3A) at the respective intermediate positions of the inner blade 4 and the outer blade 5 and the forward sweep speed V of the flying object 20. Then, the theoretical inner blade angle and outer blade angle are obtained by adding the attack angle 18 to the obtained forward sweep angle 17.
The inner blade angle α and the outer blade angle β are approximate values obtained by adjusting the amount of rotation of the link 12 (described later) so as to approach theoretical angles. Alternatively, the values may be theoretical values.

5. Other embodiments
(Variation 1)
6a is a schematic plan view showing a modified example of the suppression mechanism 6. In the modified examples and embodiments described below, only the parts different from the first embodiment described above will be described, the same parts are given the same reference numerals, and the description thereof will be omitted.
The suppression mechanism 14a of the first modified example shown in Fig. 6a does not have a curved surface 6a that is convex outward like the plate-shaped member 6. The suppression mechanism 14a has a flat plate shape. The plate surface of the flat plate-shaped suppression mechanism 14a extends obliquely backward and inward of the outer blade 5 (toward the lower right in the figure). Therefore, a suppression airflow 31 flows backward and inward (diagonally downward right in the figure) along the suppression mechanism 14a. The suppression airflow 31 prevents the wraparound airflow 30 from flowing into the upper surface 5a of the outer blade 5.

(Variation 2)
6b is a schematic plan view showing another modified example of the suppression mechanism 6. The suppression mechanism 14b of the modified example 2 shown in FIG. 6b has a flat plate shape. The flat plate-shaped suppression mechanism 14b extends straight in the front-rear direction from its front end to the vicinity beyond the middle. The suppression mechanism 14b curves inward at the rear side and extends rearward and to the right (diagonally downward right direction in the figure). Therefore, a suppression airflow 31 flows rearward and inward (diagonally downward right direction in the figure) along the plate surface of the suppression mechanism 14b. The suppression airflow 31 prevents the wraparound airflow 30 from flowing into the upper surface 5a of the outer blade 5.

(Variation 3)
Fig. 6c is a schematic plan view showing yet another modified example of the suppression mechanism 6. The suppression mechanism 14c of the modified example 3 shown in Fig. 6c has a plate shape and extends almost straight in the front-rear direction. The plate-shaped member acts like a wall that prevents the wraparound airflow 30 (see Fig. 1a) from flowing into the upper surface 5a of the outer blade 5.

(Variation 4)
Fig. 7 is a schematic plan view showing yet another modified example of the suppression mechanism 6. In the suppression mechanism 14d of the modified example 4 shown in Fig. 7, a bracket 28 extends below the portion protruding from the upper surface 5a of the outer blade 5. The bracket 29 is provided between the inner blade 4 and the outer blade 5, and is fixed to the end surface 5c of the outer blade 5 (see Fig. 1b). In this embodiment, the shaft 7 passes through the bracket 29.

(Variation 5)
Fig. 8a is a schematic plan view showing yet another modified example of the suppression mechanism 6. In a suppression mechanism 14e of the fifth modified example shown in Fig. 8a, a plate-like member 14e is protruded to the lower surface side of the outer blade 5.
Fig. 8b is a schematic diagram showing the vicinity of the communication part S from the rear of the blade 3. The suppression mechanism 14e of the modified example 5 shown in Fig. 8b is arranged so that the inner blade 4 and the outer blade 5 close the communication part S. This is expected to prevent the inflow of the wraparound airflow 30 to the upper surface 5a near the end surface 5c of the outer blade 5, and to suppress the wraparound airflow 32 from the lower surface 4b of the inner blade 4 to the upper surface 4a.

The plate-like member 14e has a curved surface 6a (hidden in FIG. 8a) on its outer side (left side of the figure). The rear side of the curved surface 6a extends rearward and inward (diagonally downward and to the right of the figure). This causes an inward suppression airflow 31 to be generated along the curved surface 6a. The suppression airflow 31 prevents the wraparound airflow 30 from flowing onto the upper surface 5a of the outer blade 5.

(others)
Although not shown, the bracket 28 of the fourth modification may be used in other modifications and embodiments.
In addition, in the first embodiment and the first to fifth modified examples, each plate-like member may protrude from both the upper and lower surfaces of the outer blade 5. By using them on both the upper and lower surfaces, it is expected that the effects obtained by using them on each surface can be achieved. In this case, different types of plate-like members may be used on the upper and lower surfaces.

Second Embodiment
Another embodiment of the blade 3 of the present invention will be described below. This embodiment is almost the same as the first embodiment described above, so only the different parts will be described and the description of the same parts will be omitted.
Fig. 9a shows a schematic plan view of another embodiment of the blade 3. The blade 24 shown in Fig. 9a is different from the blade 3 of the first embodiment in the suppression mechanism 6. As shown in the figure, the suppression mechanism 25 is interposed between the inner blade 4 and the outer blade 5, and the upper and lower surfaces of the blades are continuous. There is no gap between the inner blade 4 and the outer blade 5.
In addition, the suppression mechanism 25 can be deformed according to the change in the blade angle of the inner blade 4 and the outer blade 5. Next, when the blade angle of the inner blade 4 and the outer blade 5 returns to the original shape, the suppression mechanism 25 is a member (hereinafter, referred to as a deformable member) that can return from the deformed shape to the original shape. Such a deformable member 25 can be made of an elastic material such as rubber or synthetic resin having elasticity. The deformable member 25 is provided to be rotatable relative to the shaft 7.
According to the deformable member 25 of the present embodiment, the communication portion S (see FIG. 1a) formed with the change in the blade angle of the inner blade 4 and the outer blade 5 is blocked. Therefore, the airflow through the communication portion S, for example, the wraparound airflow 30 (see FIG. 1a) from the lower surface to the upper surface of the outer blade 5, is suppressed. This improves the propeller efficiency.

(Variation 6)
FIG. 9b is a schematic plan view showing a modified example of the deformable member 25. As shown in FIG.
The deformable member 26 of the sixth modified example shown in Fig. 9b is arranged so that multiple plate materials 26a are overlapped between the inner blade 4 and the outer blade 5. The dashed line in the figure is an illustration in which the multiple plate materials 26a are omitted. The blade equipped with the deformable member 26 is referred to as the blade 24a.
Each of these plate materials 26a is rotatable about the shaft 7. The amount of rotation increases by a predetermined amount from the inner blade 4 to the outer blade 5 in accordance with the change in the blade angle of the inner blade 4 and the outer blade 5. As a result, the multiple plate materials 26a form upper and lower surfaces that are almost continuous between the inner blade 4 and the outer blade 5 as a whole.
As a mechanism for such rotation, a link mechanism, a gear mechanism, or other known mechanism is used.
For example, in the case of a link mechanism, the amount of rotation of the plate material 26a on the adjacent outer blade 5 side is configured to be increased by a predetermined amount relative to a predetermined amount of rotation of the plate material 26a on the inner blade 4 side.
Furthermore, in the case of a gear mechanism, for example, the gear of the plate material 26a on the inner blade 4 side meshes with the gear of the plate material 26a on the adjacent outer blade 5 side. At that time, the rotation amount of the plate material 26a on the adjacent outer blade 5 side is configured to be increased by a predetermined amount with respect to a predetermined rotation amount of the plate material 26a on the inner blade 4 side.

(Variation 7)
FIG. 10 is a schematic plan view showing another modified example of the deformable member 25. As shown in FIG.
10, the deformable member 27 of the seventh modified example is composed of a retaining member 27a fixed to the shaft 7, and a tubular member 27b that covers the retaining member 27a and connects the inner blade 4 and the outer blade 5. The blade equipped with the deformable member 27 is referred to as a blade 24b.
In this embodiment, the holding member 27a is a plate-like member. The holding member 27a is housed in the cylindrical member 27b and maintains the shape of the cylindrical member 27b from the inside. In this embodiment, six holding members 27a are arranged in parallel at a predetermined interval. It is sufficient that there is one or more holding members 27a.
The cylindrical member 27b can be deformed according to the change in the blade angle of the inner blade 4 and the outer blade 5. At this time, the holding member 27a is provided inside the cylinder, so that the cylindrical member 27b is prevented from bending or twisting midway. In addition, when the blade angles of the inner blade 4 and the outer blade 5 return to their original shape, the cylindrical member 27b can also return to its original shape. The cylindrical member 27b can be made of an elastic material such as rubber or an elastic synthetic resin.
The holding member 27 a may be rotatable about the shaft 7 .

(Variation 8)
FIG. 11 is a schematic plan view showing a modification of the blade 24 (see FIG. 9a).
11 shows a blade 24c of the eighth modified example, which has a different deforming member. The deforming member 32 of the blade 24c extends in the direction in which the shaft 7 extends, as compared to the deforming member 25. The deforming member 32 has a length equal to or greater than half the total length of the blade 3.
In this embodiment, the deformation member 32 is an elastic member that connects the inner blade 4 and the outer blade 5. The shaft 7 passes through a through hole 32a formed in the deformation member 32. The deformation member 32 is provided so as to be freely rotatable with respect to the shaft 7. If the deformation member 24 is cylindrical, the through hole 32a is not necessary. A tip portion 7a of the shaft 7 is fixed inside the outer blade 5. The shaft 7 pivots the inner blade 4 and the deformation member 28. The reference numeral 12 on the inner blade 4 denotes a link 12. The shaft 7 passes through the center of the link 12.
In this embodiment, the vertical movement of one cylinder rod 8a changes the amount of rotation of two blades, the inner blade 4 and the outer blade 5. This rotation elastically deforms the deformable member 32. The overall shape of the blade 3 including the deformable member 32 is adapted to approach a shape that provides high propeller efficiency according to the forward speed of the aircraft or the takeoff/level flight state.

The inner blade 4, the outer blade 5 and the deformable member 32 may be integrated into one member. The one member may be integrally formed. The inner blade 4, the outer blade 5 and the deformable member 32 may be made of the same material.
The deformable member 32 is preferably one that can be twisted when a force is applied in the opposite directions to the distal end side and the proximal end side, and returns to its original shape when the force is released. The deformable member 32 may be made of, for example, an internal core material and an outer skin that covers the outer periphery of the core material. For example, the core material may be a foam, a honeycomb material, or even wood. The material of the outer skin may be carbon fiber reinforced plastics (CFRP), metals such as aluminum, rubber, synthetic resin, or the like.

Third Embodiment
Another embodiment of the blades 3, 24 of the present invention will be described below. This embodiment is almost the same as the first and second embodiments and the modified example described above, so only the different parts will be described and the description of the same parts will be omitted.
Fig. 12 shows a schematic plan view of another embodiment of the blade 24. The blade 33 shown in Fig. 12 is different from the blade 24 of the second embodiment and the blade 24c of the ninth modification in terms of the deformable member 34. The deformable member 34 extends further in the direction in which the shaft 7 extends than the deformable member 32. The deformable member 34 is provided so as to be rotatable relative to the shaft 7. If the deformable member 34 is cylindrical, the through hole 32a is not necessary.
The length of the deformable member 34 is about 90% or more of the total length of the blade 3. The inner blade (inner portion) 4 and the outer blade (outer portion) 5 act as base members for elastically deforming the deformable member 34. The inner blade 4 and the outer blade 5 may have some effect of generating lift as a blade.
Furthermore, when the blades have almost no effect of generating lift, they may be referred to as the inner portion (inner portion) and the outer portion (outer portion) of the blade 3, rather than the inner blade 4 and the outer blade 5. The inner portion 4 is a plate-like member for fixing the link 12. It serves as a portion for supporting the inner end of the blade. The outer portion 5 is a portion for fixing the tip portion 7a of the shaft.
The shaft 7 passes through the blade 3 from the inner end to near the outer end. A tip portion 7a of the shaft 7 is fixed inside the outer end portion 4 of the blade 3, and a base end of the shaft 7 protrudes inward from the inner end of the blade 3.
In this embodiment, the outer blade 5 is solid and is fixed near the tip 7a of the shaft 7. The outer blade 5 may be cylindrical. In the case of a cylindrical shape, the tip 7a is fixed by a bracket (not shown) provided inside the outer blade 5.

The inner blade 4, the outer blade 5 and the deformable member 34 may be integrated into one member. The one member may be formed by integral molding. The inner blade 4, the outer blade 5 and the deformable member 32 may be formed of the same material.
The deformable member 34 is preferably one that can be twisted when a force is applied in the opposite directions to the distal end side and the proximal end side, and returns to its original shape when the force is released. The deformable member 34 may be made of, for example, an internal core material and an outer skin that covers the outer periphery of the core material. For example, the core material may be a foam, a honeycomb material, or even wood. The material of the outer skin may be carbon fiber reinforced plastics (CFRP), metals such as aluminum, rubber, synthetic resin, or the like.

(Another embodiment of the propeller mechanism)
The following describes another embodiment of the propeller mechanism 1. Since this embodiment has some overlapping parts with the first embodiment described above, only the different parts will be described and a description of the overlapping parts will be omitted.

Figure 13a shows a schematic cross-sectional view of another embodiment of the propeller mechanism 1. The angle change mechanism 35 of the propeller mechanism 41 shown in Figure 13a includes a cylinder mechanism 36. The cylinder mechanism 36 is provided on the hub 1a. The hub 1a is formed with a cylinder case 37 of the cylinder mechanism 36. A piston 38 is provided in the cylinder case 37 and moves inside (up and down in the figure). A propeller shaft (rod) 39 extends from the piston 38 to the outside of the cylinder case 37 (down in the figure). A bulge 39a is provided in the middle of the rod 39. The bulge 39a moves up and down together with the piston 38. The bulge 39a is connected to the link 12. The link 12 is configured to rotate by the up and down movement of the bulge 39a.

13b shows a schematic cross-sectional view of the rod 39. As shown in FIG. 13b, the rod 39 is made up of a shaft member 42 and a cylindrical member 43.
The shaft member 42 comprises a large diameter base portion 42a, a shaft portion 42b extending upward from the base portion 42a via a step portion, and a protruding portion 42c protruding upward from the tip of the shaft portion 42b via a step portion 42d.
The cylindrical member 43 is composed of a cylindrical portion 43a and a large diameter portion (piston) 38 at the upper end of the cylindrical portion 43a. An opening 43b is formed in the center of the large diameter portion 38.

A fluid supply passage 44 for driving the cylinder mechanism 36 is formed in the axial direction of the shaft member 42. Oil holes 44a, 44b that communicate with the supply passage 44 are formed at the upper and lower ends of the shaft member 42, respectively. The space formed between the cylinder case 37 and the piston 38 (see FIG. 13a) is a hydraulic chamber 45. The oil hole 44a communicates with the hydraulic chamber 45. The arrows near the oil holes 44a, 44b show the direction of oil flow toward the hydraulic chamber 45. The direction opposite to the arrows is the direction in which oil is discharged from the hydraulic chamber 45.

The shaft member 42 is housed in the tubular member 43 and is integrated with it (see FIG. 13c). The side peripheral surface of the base 42a of the shaft member 42 is almost in contact with the inner peripheral surface of the tubular portion 43a of the tubular member 43. The protruding portion 42b of the shaft member 42 is passed through the opening 43b of the large diameter portion 38. The outer peripheral surface of the protruding portion 42b is almost in contact with the inner surface of the opening 43b. The step portion 42d of the shaft member 42 is in contact with the ceiling surface of the tubular portion 43a. Almost in contact means that the protruding portion 42b is in contact to such an extent that oil does not leak during operation of the cylinder mechanism 36. The space formed by the shaft member 42 and the tubular member 43 is the second supply passage 46. Oil holes 46a and 46b that communicate with the second supply passage 46 are formed at the top and bottom of the side wall of the tubular portion 43a of the tubular member 43. The upper oil hole 46a communicates with the cylinder case 37. On the other hand, the lower oil hole 46b is formed outside the cylinder case 37. The space formed between the piston 38 and the second piston 40 (see FIG. 13a) is the second hydraulic chamber 47. The oil hole 46a is connected to the second hydraulic chamber 47. The arrows near the oil holes 46a and 46b show the direction in which the oil flows toward the second hydraulic chamber 47. The direction opposite to the arrows is the direction in which the oil is discharged from the hydraulic chamber 45.

A second piston 40 is slidably provided on the rod 39. The rod 39 passes through the second piston 40. The second piston 40 is pivotally supported by the rod 39. The second piston 40 moves up and down inside the cylinder case 37. A cylindrical portion 40a is provided below the second piston 40. The rod 39 passes through the cylindrical portion 40a. The cylindrical portion 40a extends to the outside of the cylinder case 37 (toward the bottom in the figure). A bulge 40b is provided at the lower end of the cylindrical portion 40a. The bulge 40b is connected to the shaft 7. The shaft 7 is configured to rotate due to the up and down movement of the bulge 40b. The rotation direction of the shaft 7 is opposite to the rotation direction of the link 12.
The cylinder mechanism 36 constitutes a drive mechanism 13a of the angle changing mechanism 35. The link 12, the bulging portion 39a, and the bulging portion 40b constitute a transmission mechanism 13b of the angle changing mechanism 35.

When hydraulic pressure is applied to the hydraulic chamber 45 via the supply passage 44, the piston 38 descends, and the inner blade 4 rotates in the L direction via the link 12.
On the other hand, when hydraulic pressure is applied to the second hydraulic chamber 47 via the second supply passage 46, a force acts in a direction to move the second piston 40 downward, and a force acts in a direction to rotate the outer blade (outer portion) 5 in the R direction via the shaft 7. The second piston 40 may be allowed to move downward to some extent. The downward movement allows the outer blade (outer portion) 5 to rotate in the R direction via the shaft 7.
As a result, the blade 3 can be twisted by applying force from the vicinity of the inner end and the vicinity of the outer end. The amount of twisting is based on the amount that the piston 38 descends.

When the piston 38 is lowered, hydraulic pressure is released from the second hydraulic chamber 47. When the piston 38 has lowered a predetermined amount, hydraulic pressure is applied to the second hydraulic chamber 47. This maintains the piston 38 at a predetermined lowering amount, and the blade 3 is twisted by an amount based on that lowering amount.

Alternatively, the base end of the shaft 7 or the link 12 may be fixed to a member on the aircraft body side, and the other may be rotated hydraulically.
Furthermore, the shaft 7 may be connected to the swollen portion 39 a of the rod 39 , and the link 12 may be connected to the swollen portion 40 a of the second piston 40 .

[6. Other]
The above-described embodiments and modifications can be used in appropriate combination.
The flying object 20 may not fly, but may be an aircraft 20 that is propelled on the ground by a propeller mechanism 1, such as a car or a hovercraft.
The flying vehicle 20 may be piloted or may be remotely controlled from a ground control station or air traffic control.
The flying object 20 may be an airplane, a helicopter, a drone, or the like. Also, the propeller shaft 2 may be tilted without tilting the main wing 21. For example, the propeller mechanism 1 may be provided at the tip of the main wing 21, and the propeller shaft 2 may be tilted.
Furthermore, in the case of a drone, for example, the main wing 21 and the propeller shaft 2 may not be tilted, but the entire flying object may be tilted.
For example, in this embodiment, the flying object 20 is used as a vertical take-off and landing aircraft (VTOL aircraft) or a short take-off and vertical landing aircraft (STOVL aircraft) that runs a short distance during take-off and lands vertically during landing.

In this embodiment, the number of blades 3 is two, but three or more blades may be used. In that case, an inner rod 10 and an outer rod 11 for the new blade, and further angle changing mechanisms 13 and 35 may be provided.
In this embodiment, one blade 3 has one inner blade 4, but a plurality of inner blades may be provided.
In this embodiment, the blade 3 is divided into the inner blade 4 and the outer blade 5 at a midpoint in the longitudinal direction of the blade 3, but the blade 3 may be divided at another position.
The overall shape of the blades 3, 24 (24a, 24b, 24c) including the inner blade 4, the outer blade 5 and the deformable members 25, 26, 27, 32, and further the blade 33, i.e., in a non-rotating state, may be previously set to have a predetermined blade angle according to the longitudinal distance. For example, the blade may be previously set to have a blade angle suitable for vertical takeoff, and the inner blade (inner portion) 4 and the outer blade (outer portion) 5 may be rotated according to the rotation speed of the propeller shaft 2 during horizontal flight.

The angle changing mechanisms 13 and 35 may be any known technology for changing the blade angle of a helicopter or airplane propeller.
A separate link 12 may be connected to the inner rod 4 .
The cylinder mechanism 8 may be one that is driven by hydraulic pressure or the like.
Instead of the push-pull rods 10, 11, a control cable consisting of a push-pull cable and a conduit may be used.

In this embodiment, the blade 3 is divided into the inner blade 4 and the outer blade 5 at the midpoint in the length direction, but the blade 3 may be divided at other positions.

[7. Summary]
(1) The blade 3 of the present invention is a blade 3 used for a flying body 20, and comprises an inner blade 4 and an outer blade 5 provided outside the inner blade 4, the blade angles 23 formed by the inner blade 4 and the outer blade 5 with the propeller rotation plane 22 are each variable, and a suppression mechanism 6 is provided near the adjacent portion of the outer blade 5 and the inner blade 4, and the suppression mechanism 6 is characterized in that it suppresses the airflow 30 that flows around from the lower surface 5b of the outer blade 5 to the upper surface 5a of the outer blade 5 via the vicinity of the inner end face 5c of the outer blade 5.
The circumnavigating air current 30 tends to reduce the air pressure on the lower surface 5b near the inner end of the outer blade 5. Furthermore, it tends to cause a vortex to be generated behind the blade 3. The vortex may cause induced resistance that acts as a resistance to the forward movement of the flying object 20.
That is, by suppressing the wraparound airflow 30, it is possible to suppress the decrease in pressure on the lower surface 5b of the outer blade 5, and further reduce the resistance to the forward movement of the flying object 20. This makes it possible to increase the ratio of the work of the propeller 1a to the work of the rotary drive mechanism 19 that rotates the propeller shaft 2. In other words, since the efficiency of the propeller is high, there is little waste and energy is saved.

(2) Furthermore, if the suppression mechanism 6 is a deformable member 25 provided between the inner blade 4 and the outer blade 5, and changes shape in response to changes in the blade angles of the inner blade 4 and the outer blade 5, and the deformable member 6 deforms in response to changes in the blade angle so as to make the upper and lower surfaces of the inner blade 4 and the outer blade 5 almost continuous, the generation of the circumferential airflow 30 can be suppressed. This improves the propeller efficiency.

(3) Furthermore, when the deformable member 25 is composed of a retaining member 27a and a tubular member 27b that is arranged around the retaining member 27a and that deforms in response to changes in the blade angles of the inner blade 4 and the outer blade 5, the simple configuration can accommodate changes in the blade angles of the inner blade 4 and the outer blade 5, and the simple configuration can also maintain the overall shape of the blade 3.

(4) (6) The propeller mechanism 1 of the present invention includes the propeller blades 3 described above and an angle changing mechanism 13 for changing the blade angles of the inner blades 4 and the outer blades 5. The flying object 20 of the present invention includes the propeller mechanism 1 described above and a main body 20a that flies due to the propeller mechanism 1.
Since the propeller mechanism 1 can change the inner blade angle α and the outer blade angle β separately for the inner blade 4 and the outer blade 5, it is possible to approximate a shape suitable for the speed (or airspeed) of the aircraft propelling the blades 3 and the rotation speed of the propeller shaft 2. For example, it is possible to approximate a propeller shape suitable for each of the following conditions: a low speed state during vertical takeoff, a high speed state during horizontal flight, or a state in which the propeller shaft 2 is tilted obliquely. Therefore, the ratio of the work of the propeller 1a to the work of the rotary drive mechanism 19 that rotates the propeller shaft 2 is high. In other words, the efficiency of the propeller is high.
In addition, the suppression mechanism 6 can suppress the airflow 30 that passes between the inner blade 4 and the outer blade 5 and flows around from the lower surface of the blade 3 to the upper surface.
This allows the propeller to be more efficient, resulting in less waste and more energy savings.

(5) Another aspect 41 of the propeller mechanism of the present invention includes a shaft 7 extending in a direction approximately perpendicular to the propeller shaft 39 and rotatable about its own axis, a blade 3 through which the shaft passes from its inner end to near its outer end, and an angle changing mechanism 36 for changing the blade angle of the blade, wherein the vicinity of the tip of the shaft 7 is fixed inside the blade 3 near its outer end and the base end of the shaft 7 protrudes inward from the inner end of the blade 3, and the blade angle is changed by twisting the blade 3 near its inner end 4 and the blade 3 near its outer end 5 in opposite directions via the shaft 7 by the angle changing mechanism 36.
This allows the propeller to be more efficient, resulting in less waste and more energy savings.

(7) In such a blade 3, the suppression mechanism 6 is a plate-like member that protrudes from at least one side of the outer blade 5, and the plate-like member extends in the approximate width direction of the blade 3, so that it can obstruct the airflow that wraps around the upper surface. This reduces the induced resistance to the flying object 20, and improves the propeller efficiency.

(8) Furthermore, when the plate-like member 6 protrudes toward the upper surface 5a of the outer blade 5 and the plate surface of the plate-like member 6 faces rearward and inward in the width direction, the suppression airflow C31 guided along the plate surface almost collides with the circulating airflow 30, thereby weakening the circulating airflow 30 and improving the propeller efficiency.

1 Propeller mechanism 1a Propeller 1b Hub 1c Propeller cover 2 Propeller shaft 3 Blade 3a Upper surface 3b Lower surface 3c Blade portion 4 Inner blade 4a Upper surface 4b Lower surface 4c Through hole 5 Outer blade 5a Upper surface 5b Lower surface 5c End surface 6 Suppression mechanism 6a Curved surface 6b Front inclined portion 6c Rear inclined portion 6d Angle 6e Height 7 Shaft 8 Cylinder mechanism 8a Cylinder rod 9 Rotating slider 9a Central hole 10 Inner rod 11 Outer rod 12 Link 13 Angle change mechanism 13a Drive mechanism 13b Transmission mechanism 14a Suppression mechanism (variation example 1)
14b Suppression mechanism (variation 2)
14c Suppression mechanism (variation 3)
14d Suppression mechanism (variation 4)
14e Suppression mechanism (variation 5)
15 Adjacent portion 16 Gap 17 Forward sweep angle 18 Attack angle 19 Drive mechanism 20 Flying body 20a Body 21 Main wing 22 Rotation surface 23 Blade angle 24 Blade (Second embodiment)
24a Blade (Modification 6)
24b Blade (Modification 7)
25 Suppression mechanism (deformable member)
26 Deformable member (Modification 6)
26a Plate material 27 Deformable member (Modification 7)
27a Holding member 27b Cylindrical member 28a Angle (Modification 1)
28b Angle (Modification 2)
28c Angle (variation 3)
29 Bracket 30 Airflow that turns around 30a Airflow that will turn around 31 Suppression airflow 32 Deformation member (Modification 8)
32a Through hole 33 Blade (third embodiment)
34 Deformable member (Modification 9)
35 Angle change mechanism 36 Cylinder mechanism 37 Cylinder case 38 Piston 39 Rod 39a Expanded portion 40 Second piston 40a Cylindrical portion 40b Expanded portion 41 Propeller mechanism 42 Shaft member 42a Base portion 42b Shaft portion 42c Projecting portion 42d Step portion 43 Cylindrical member 43a Cylindrical portion 43b Opening 44 Supply passage 44a Oil hole 44b Oil hole 45 Hydraulic chamber 46 Second supply passage 46a Oil hole 46b Oil hole 47 Second hydraulic chamber α Inner blade angle β Outer blade angle

Claims (8)

A propeller blade for use in an aerial vehicle,
It is composed of an inner wing and an outer wing provided on the outside of the inner wing,
The blade angles of the inner blade and the outer blade relative to the rotation plane of the propeller are variable,
A suppression mechanism is provided near adjacent portions of the outer blade and the inner blade,
The suppression mechanism suppresses airflow that flows around from the lower surface to the upper surface of the outer blade via the vicinity of the inner end surface of the outer blade. The suppression mechanism is a deformable member provided between the inner blade and the outer blade, and changes its shape in response to changes in the blade angles of the inner blade and the outer blade,
2. A propeller blade according to claim 1, wherein the deformable member deforms in response to a change in the blade angle so as to make upper and lower surfaces of the inner blade and the outer blade substantially continuous. The deformation member includes a holding member,
5. The propeller blade according to claim 4, further comprising a tubular member disposed around the retaining member and adapted to deform in response to changes in the blade angles of the inner blade and the outer blade. A propeller blade according to any one of claims 1, 2 and 3;
A propeller mechanism comprising an angle changing mechanism for changing the blade angle. A shaft extending in a direction substantially perpendicular to the propeller shaft and rotatable about its own axis;
A blade through which the shaft passes from an inner end to a vicinity of an outer end;
an angle changing mechanism for changing the blade angle of the blade,
a tip end of the shaft is fixed inside the outer end of the blade, and a base end of the shaft protrudes inward from the inner end of the blade;
A propeller mechanism in which the angle change mechanism twists the inner end and the outer end of the blade in opposite directions via the shaft, thereby changing the blade angle. A flying object comprising the propeller mechanism according to claim 4 or 5 and a main body that flies using the propeller mechanism. The suppression mechanism is a plate-like member protruding from at least one surface side of the outer blade,
2. The propeller blade of claim 1, wherein the plate-like member extends generally in the width direction of the blade. The plate-like member protrudes toward the upper surface of the outer blade,
8. The propeller blade according to claim 7, wherein the plate surface of the plate-like member faces rearward and inward in the width direction.

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