Rotor blades of a lift rotor

Abstract

A foldable rotor blade (152, 153) includes a hinge element (173; 240) defined by two hinge axes arranged in parallel, and two blade portions (171, 172), each blade portion being connected to the hinge element (173; 240) to be rotatable relative to the respective hinge axis. The rotor blade has an extended state in which the blade portions are substantially aligned with each other; the rotor blade has a folded state in which each blade portion rotates relative to the hinge element so that the blade portions are substantially parallel to each other. The blade has a cord (14), and the hinge axis is substantially parallel to the chord. The blade portion has an upper surface which faces each other in the folded state and is flush with the intermediate hinge element in the extended state.

Description

Technical Field

[0001] The present invention generally relates to rotor blades of a lift rotor. In the context of the present invention, a "lift rotor" is a rotor that provides lift to an aircraft, such as a helicopter or a tiltrotor. The present invention particularly relates to the field of convertible vehicles having a flight mode and a road traffic mode. Background Art

[0002] Generally, the length of a rotor blade is much greater than the width or length of the associated vehicle. This length translates into the amount of ground space occupied when the vehicle is stationary. In some cases, it is desirable to reduce the space, for example when parked inside a shelter or when transported by a truck or an aircraft.

[0003] For a rotor with two blades, the overall width of the vehicle can be reduced by aligning the rotor blades longitudinally with the vehicle. If this is not sufficient, it is well known that the rotor blades can be removed, but this requires lifting equipment and / or personnel to climb on top of the vehicle. Summary of the Invention

[0004] The above solutions are not applicable to convertible vehicles. Due to the nature of such vehicles, it must be possible for a person standing on the ground to convert it from the flight mode to the road traffic mode in a relatively simple and quick manner. In addition, in the road traffic mode, it is not desirable to discard the rotor blades, so removing the blades is not the preferred solution.

[0005] Furthermore, in the road traffic mode, simply positioning the rotor so that the rotor blades are longitudinally aligned in opposite directions is not a suitable solution. In the road traffic mode, the vehicle as a whole should comply with road traffic regulations, have a low center of gravity, and low air resistance, etc.

[0006] If the rotor blades are hinged to a central rotor hub and rotated relative to the central hub to a position parallel to each other, i.e., in the same direction parallel to the vehicle longitudinally, the above requirements can be met to a certain extent.

[0007] However, in order to perform the flight mode, a relatively large blade length is required, and the vehicle body is preferably compact. Such large blades will cause problems not only in terms of aerodynamics but also in terms of protruding from the vehicle profile. Therefore, the present invention proposes that each rotor blade be foldable.

[0008] Figure 1AFIG. 0 is a top view of the rotor blade 10. It can be seen that the rotor blade is slender, having a relatively large length and a small width. The rotor blade 10 has a proximal end 11 adapted to be connected to a rotor hub (not shown) and an opposite distal free end 12. The quarter chord line connecting the proximal end 11 and the distal end 12 is the blade centerline 13, and its length determines the length of the rotor blade 10.

[0009] Figure 1B FIG. 4 is a schematic cross-sectional view of the rotor blade 10 in a plane perpendicular to the blade centerline 13. The blade has an aerodynamic wing profile, having a leading edge 16 and a trailing edge 15. The straight line connecting the leading edge 16 and the trailing edge 15 is denoted as the chord 14. It can be seen that, measured in a direction perpendicular to the chord 14 and the blade centerline 13, the length of the chord 14 is greater than the maximum thickness of the blade 10.

[0010] Hereinafter, the virtual plane defined by the chord 14 and the blade centerline 13 is denoted as the chord plane 17. It should be noted that during operation, the rotor blade 10 will rotate about a generally vertical axis of rotation within a generally horizontal chord plane 17.

[0011] According to an important aspect of the present invention, the rotor blade includes a hinge structure between its proximal end and its distal free end, and the hinge axis of this hinge structure is generally parallel to the chord plane 17 and perpendicular to the blade centerline 13. This hinge structure allows the rotor blade to fold about the axis along a direction substantially parallel to the chord 14.

[0012] In the operating position, the rotor blade 10 is positioned at a relatively large height above the ground, as long as sufficient ground clearance can be provided. The chord 14 is substantially horizontal. When folding the rotor blade in this operating position, a hinge operation needs to be performed in a vertical plane, which is difficult or even impossible for a person standing on the ground. In the vehicle according to the present invention, the rotor hub is mounted on the top of a mast located above the vehicle. The lower end of the mast is hinged relative to the vehicle, so that the mast can be lowered to a substantially horizontal position. The axis of rotation of the rotor hub is fixed relative to the mast. Therefore, when the mast is in the lowered horizontal position, the axis of rotation of the rotor hub is also in a horizontal direction. When the mast is lowered, the two rotor blades remain parallel to the hinge axis. After the mast is lowered, the two rotor blades are still generally horizontally extended, but at this time the chord plane 17 has rotated approximately 90° to a generally vertical direction, such that the chord 14 is substantially vertical.

[0013] At this time, when the rotor blade folds about the axis along a direction substantially parallel to the chord 14, it needs to be hinged about a substantially vertical axis, that is, a displacement is generated in a horizontal plane, which can be easily completed by a person.

[0014] When folding the rotor blade 10, it is desirable that the two blade parts can be placed parallel to each other, i.e., a hinge angle of 180° should be achieved. A single-axis hinge can be used, but in this case, the hinge axis must be arranged outside the aerodynamic wing profile of the blade, which is not desirable because it increases the aerodynamic drag. If the hinge is completely within the aerodynamic wing profile of the blade, it is impossible to hinge at 180°.

[0015] To overcome these problems, the hinge structure proposed by the present invention has at least two hinge axes arranged in parallel. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] These and other aspects, features, and advantages of the present invention will be described in connection with one or more preferred embodiments with reference to the accompanying drawings, in which like reference numerals represent the same or similar components, and in which:

[0017] Figure 1A is a top view of the rotor blade;

[0018] Figure 1B is a schematic cross-sectional view of the rotor blade;

[0019] Figure 2 is a perspective view of a convertible flying / driving vehicle in a flying state according to the present invention;

[0020] Figure 3 is a side view showing the main shaft structure of the vehicle in a first intermediate state between the flying state and the road driving state;

[0021] Figure 4 is a side view showing the vehicle in a second intermediate state between the flying state and the road driving state;

[0022] Figure 5 is a top view of the vehicle in this second intermediate state;

[0023] Figure 6 is a top view of the vehicle in a third intermediate state;

[0024] Figure 7 is similar to Figure 6 a top view showing the right rotor blade of the vehicle in the road driving state;

[0025] Figure 8A is a perspective view schematically showing the main components of the hinge structure according to the present invention in a separated state;

[0026] Figure 8B is a perspective view showing a more realistic view of the components in an assembled state;

[0027] Figure 8C is similar toFigure 8B A similar view, in which one blade portion is connected to a blade connector;

[0028] Figure 9A is a perspective view of a central hinge portion of a rotor blade;

[0029] Figure 9B is similar to Figure 9A a similar view, in which one blade portion rotates;

[0030] Figure 9C is similar to Figure 9A a similar view, in which two blade portions rotate;

[0031] Figure 10A shows two blade portions interfering with each other;

[0032] Figure 10B shows two blade portions according to the present invention, in which one blade portion allows the other blade portion to rotate without interference;

[0033] Figure 11A -C schematically shows the operating principle of an embodiment of a preferred folding control device according to the present invention. Detailed Description of the Invention

[0034] Figure 2 is a perspective view of a convertible flying / driving vehicle 100 according to the present invention. The vehicle 100 includes an elongated body 110 that contains an interior compartment for accommodating passengers and is sized comparable to that of an automobile. The vehicle 100 includes a chassis system 120 that includes a front wheel 121 and two rear wheels 122, 123. The rear end of the vehicle 100 includes a propeller 130 that provides propulsion force in the flight mode and can be folded and accommodated inside the body in the driving mode.

[0035] The vehicle 100 houses an engine (not shown for simplicity). In the driving mode, the engine power is transmitted to the rear wheels to propel the vehicle like a normal automobile on the road. In the flight mode, the engine power is transmitted to the propeller 130 to provide propulsion force in the air.

[0036] The vehicle 100 is provided with a main shaft 140, the lower end 141 of which is hinged to the top of the body 110 near the rear end of the body 110. At the top end 142 of the main shaft 140, the main shaft 140 rotatably carries a lifting rotor 150 that provides a lifting force to the vehicle 100 when rotating. Although the rotor 150 can receive engine power to rotate, the rotor can also be of the helicopter type. The rotor 150 includes a rotor hub 151 and two rotor blades 152, 153.

[0037] The vehicle 100 further includes an extendable tail structure 160, which includes two tailfoils 161, 162 mounted at the distal end of an extendable tail boom 163. The proximal end of the tail boom 163 is hinged to the main shaft 140, near the top end 142 of the main shaft. At a position behind the main shaft 140, the tail structure 160 includes a boom support 164, whose lower end is hinged to the vehicle body 110 and upper end is hinged to the tail boom 163.

[0038] Figure 2 Shows the vehicle 100 in a flying state. The propeller 130 is deployed. The main shaft 140 is rotated to a vertical position, and so is the tail boom support 164. The tail boom 163 extends and is in a raised level to extend well beyond the deployed propeller 130. The chord planes of the rotor blades 152, 153 extend substantially horizontally.

[0039] Figure 3 Is a side schematic view of the main shaft structure of the vehicle in a first intermediate state between the flying state and the road driving state. The propeller 130 is folded and retracted and not visible. The main shaft 140 is lowered to an angle of approximately 45° with respect to the horizontal plane; the tail boom support 164 and the tail boom 163 follow suit. The rotor blades 152, 153 extend in a lateral direction with respect to the vehicle, i.e., perpendicular to the plane of the drawing.

[0040] Figure 4 Is a side schematic view of the vehicle in a second intermediate state between the flying state and the road driving state. The propeller 130 is folded and retracted and not visible. The main shaft 140 is lowered to a substantially horizontal position; the tail boom support 164 and the tail boom 163 follow suit, so the tail boom 163 is also substantially horizontally placed near the top of the vehicle at this time. The rotor blades 152, 153 still extend in a lateral direction with respect to the vehicle, i.e., perpendicular to the plane of the drawing. The rotor blades 152, 153 are hinged to the rotor hub 151 about their respective hinge axes 154, 155, and the hinge axes 154, 155 are substantially parallel to the chord planes of the rotor blades. Figure 4 Clearly shows these hinge axes, which are now vertical and are usually represented by dashed lines.

[0041] Figure 5Is a top view of the vehicle in the second intermediate state. The hinge axes 154, 155 extend perpendicular to the plane of this figure. This figure clearly shows that the lengths of the rotor blades 152, 153 are much greater than the length of the vehicle body 110. According to the invention, each rotor blade 152, 153 consists of two rotor blade parts 171, 172, which are hinged together at the hinge section 173 and will be explained in more detail later. The two rotor blade parts 171, 172 have approximately equal lengths, but this is not essential for the invention. Additionally, it may be advantageous if the distal end part 172 is slightly shorter than the proximal end part 171.

[0042] Figure 6 Is a schematic top view of the vehicle in the third intermediate state. Compared with the Figure 5 second intermediate state in, one of the rotor blades 153 has been (manually) rotated towards the rear of the vehicle body 110 by an angle of approximately 60°, and it should be noted that the exact value of this angle is not relevant. Additionally, the distal end part 172 has been rotated forward relative to the proximal end part 171 in order to "fold" this rotor blade. Note that the proximal end part 171 can be rotated to the rear first, and then the distal end part 172 can be folded forward relative to the proximal end part 171, but it is also possible to first fold the distal end part 172 forward relative to the proximal end part 171 and then rotate the folded blade 153 to the rear. The rotation and folding operations can also be carried out simultaneously.

[0043] Figure 7 Is a top view similar to Figure 6 showing the right rotor blade 153 of the vehicle 100 in the road driving state. The distal end part 172 has been rotated forward 180 degrees relative to the proximal end part 171 and is parallel to the corresponding proximal end part 171. In turn, the proximal end part 171 has been rotated further to the rear and now extends substantially parallel to the main shaft 140 in the longitudinal direction of the vehicle. The hinge section 173 is located at the rear end of the vehicle body 110 and there is no need to extend beyond the rear. When both rotor blades 152 and 153 are folded in this way, the main shaft 140 is located between them, the width of the tail is greater than that of the vehicle body 110 and also greater than that of the rotor blades in this folded state, so that the tail beam 163 can be pushed in, enabling the tail wing to be located outside the vehicle body close to the vehicle body and close to the folded rotor blades, as shown. The vehicle as a whole is now very compact and suitable for use as an "ordinary" car.

[0044] An important aspect of the invention relates to the design of the hinge section 173 of each rotor blade. Hereinafter, the hinge structure of this hinge part is generally denoted by the reference numeral 200. The object of the invention is to provide a hinge design such that in the extended state of the rotor blades 152, 153, the blade parts 171, 172 together with the hinge section 173 provide an aerodynamically continuous outer blade surface without components such as interruptions, recesses or protrusions that may interfere with the air flow, thereby increasing drag and reducing efficiency.

[0045] Figure 8A and 8B is a perspective view of the main components of the hinge structure 200 according to an embodiment of the present invention. Figure 8A is a schematic view of these components in a disassembled state, while Figure 8B is a more realistic view of these components in an assembled state.

[0046] The hinge structure 200 includes a first blade connector 210, a central hinge element 240, and a second blade connector 270.

[0047] The central hinge element 240 has a central body 241, a first set of parallel connecting flanges 242, and a second set of parallel connecting flanges 243. The first set of parallel connecting flanges 242 extends away from the central body 241 in a first direction, and the second set of parallel connecting flanges 243 extends away from the central body 241 in an opposite second direction. A first cylindrical hole 244 vertically penetrates the first flange 242, and a second cylindrical hole 245 vertically penetrates the second flange 243. It should be noted that the number of connecting flanges is not particularly relevant to the present invention. In fact, a hinge having only one connecting flange in each direction is also possible.

[0048] The first blade connector 210 includes a blade connection portion 211 and a hinge portion 212. The blade connection portion 211 is designed to allow connection with the first blade portion; its precise shape will be designed in combination with the corresponding blade portion. The hinge portion 212 includes a set of parallel connecting flanges 213, which are directly or through an intermediate body portion connected to the connection portion 211. A cylindrical hole 214 vertically penetrates the connecting flange 213. Similarly, the number of connecting flanges here is not particularly relevant to the present invention, and this number can also be as low as one.

[0049] The design of the second blade connector 270 is equivalent to that of the first blade connector 210 and may even be the same. It includes a blade connection portion 271 and a hinge portion 272. The hinge portion 272 is provided with a set of parallel connecting flanges 273 connected to the connection portion 271, and a cylindrical hole 274 vertically penetrating the connecting flange 273.

[0050] The flanges 242, 243, 213, 273 have parallel sides that extend perpendicular to the axes of the cylindrical holes 214, 244, 245, 275. The flanges match each other, that is, the widths of the flanges 213, 273 of the blade connectors 210, 270 correspond to the distance between the flanges 242, 243 of the central hinge element 240. Conversely, the widths of the flanges 242, 243 of the central hinge element 240 correspond to the distance between the flanges 213, 273 of the blade connectors 210, 270.

[0051] In the assembled state ( Figure 8B ), the flanges are positioned in an intermeshing position, and the flanges 213, 273 of the blade connectors 210, 270 are located between the flanges 242, 243 of the central hinge element 240, and the flanges 242, 243 of the central hinge element 240 are located between the flanges 213, 273 of the blade connectors 210, 270, and the corresponding holes 214, 244 and 274, 245 are aligned with each other. The first cylindrical hinge shaft 251 is pushed into the aligned holes 214, 244, and the second cylindrical hinge shaft 252 is pushed into the aligned holes 274, 245. It should be clear that now the first blade connector 210 can rotate relative to the central hinge element 240 about the first cylindrical hinge shaft 251, and the second blade connector 270 can rotate relative to the central hinge element 240 about the second cylindrical hinge shaft 252.

[0052] In Figure 8B the important features of the hinge structure 200 according to the present invention can be seen. The central hinge element 240 has an upper surface 246 which is common to the central body 241 and all the flanges 242, 243. The flange 213 of the first blade connector 210 has a flush upper surface 215, and the flange 273 of the second blade connector 270 has a flush upper surface 275. In the extended state of the hinge structure 200, the flange 213 of the first blade connector 210 extends to the central body 241 of the central hinge element 240 without any gap, and the flange 273 of the second blade connector 270 extends to the central body 241 of the central hinge element 240 without any gap. The upper surface 246 of the central hinge element 240 is flush and adjacent to the upper surface 215 of the flange 213 of the first blade connector 210, and is flush and adjacent to the upper surface 275 of the flange 273 of the second blade connector 270.

[0053] Figure 8C is a view similar to Figure 8B where a blade portion (e.g., 171) is connected to the second blade connector 270. The outer skin of the blade portion 171 is completely flush with the flange 273 of the second blade connector 270. This also applies to the other blade portion connected to the first blade connector 210, which is not shown separately in the figure. It can be seen that in the forward and backward directions, i.e., in the direction parallel to the hinge axis, the blade portion 171 extends beyond the hinge profile, and at these positions, the blade portion extends further longitudinally such that in the extended state, the ends of the two blade portions contact each other or are as close as possible to obtain a nearly seamless transition between the two blade portions.

[0054] It should be clear that in the extended state of the hinge, the two blade portions 171, 172 together with the hinge structure 200 define a seamless and flush upper blade surface without interruption.Figure 9A This is also schematically illustrated. On the lower side, the outer surfaces of the blade portions 171 and 172 are connected to each other in a flush manner, so the exact shape of the lower surface of the blade connector and the central hinge element is not particularly relevant.

[0055] Figure 9A is a schematic perspective view of the central hinge portion of a rotor blade, showing the central hinge element 240 and two blade portions 171, 172, which have a single seam 174 at their contact point.

[0056] Considering that the hinge structure 200 has two hinge axes arranged parallel to each other at a certain distance, and the two blade portions 171, 172 meet each other at a position between these two axes, the two blade portions 171, 172 must not rotate simultaneously, otherwise they will interfere with each other. This is as Figure 10A shown. The two blade portions 171, 172 meet each other at an upper point A above the hinge plane and at a lower point B below the said plane, and this hinge plane is defined by the hinge axes 251, 152. Assume that the two blade portions 171, 172 are folded upwards, as shown by the arrow P1. It can be easily seen that at the lower point B, the two blade portions 171, 172 will move away from each other, as shown by the arrow P2, but at the upper point A, the two blade portions 171, 172 will (try to) move closer to each other.

[0057] To avoid this situation, in the present invention, the ends of the two blade portions 171, 172 facing each other, that is, the proximal end of the distal blade portion 172 and the distal end of the proximal blade portion 171, are shaped such that one allows the other to rotate without interference, as Figure 10B shown. In particular, above the said hinge plane, the ends of the two blade portions 171, 172 may have a cylindrical profile around the first hinge axis 251, as shown at 175. Now it can be seen that the second blade portion 172 cannot be hinged, but the first blade portion 171 can rotate without interfering with the second blade portion 172 - see Figure 9B . After completing this rotation, the second blade portion 172 can be rotated without interfering with the first blade portion 171 - see Figure 9C .

[0058] For the reverse rotation, that is, unfolding, the rotation sequence should be reversed.

[0059] Figure 9A -C schematically shows the rotor blade 153 in the normal operating direction, that is, the chord 14 is basically horizontal. It can be seen that after folding, the upper surfaces 171u, 172u of the blade portions 171, 172 face each other ( Figure 9C) and in the extended state, the upper surfaces 171u, 172u are flush with each other and the central hinge element 240 is located therebetween. Figure 9A ) Refer to Figures 4 - 5 -6-7, it should be noted that in fact, in the folded state, the blade has rotated approximately 90°, such that the chord 14 is substantially vertical.

[0060] As can be seen from the above, the two blade parts 171, 172 should be folded and unfolded in the correct folding sequence. Preferably, the folding sequence is not determined by the user's skill, but the hinge structure 200 is provided with safety features that ensure the correct folding sequence without the user having to consider.

[0061] Figure 11A -C schematically shows the operating principle of an embodiment of the preferred folding control device 300 according to the present invention. The first hinge shaft 251 is provided with a first groove 311, and the second hinge shaft 252 is provided with a second groove 312. The central hinge element 240 is provided with a locking pin 330, which is located between the two hinge shafts 251, 252, and can axially slide in the chamber 320 of the central hinge element 240, and the length of the locking pin 330 is greater than the mutual distance between the two hinge shafts 251, 252.

[0062] The angular position of the first groove 311 relative to the first hinge shaft 251 is such that the groove aligns with the first end of the locking pin 330 when the first blade connector 210 is in the extended state. The angular position of the second groove 312 relative to the second hinge shaft 252 is such that the groove aligns with the opposite second end of the locking pin 330 when the second blade connector 270 is in the folded state.

[0063] Figure 11A shows the hinge structure 200 in the fully extended state, i.e., the flight state. The first end of the locking pin 330 extends into the first groove 311, thereby preventing the first hinge shaft 251 connected to the first blade connector 210 from rotating relative to the central hinge element 240. The other end of the locking pin 330 abuts against the outer surface of the second hinge shaft 252 to prevent the locking pin 300 from releasing the first hinge shaft 251. The second blade connector 270 can freely rotate upward.

[0064] When the second blade connector 270 reaches its folded state, the second groove 312 aligns with the locking pin 330. The locking pin 330 now moves, and its second end enters the second groove 312 to lock the second blade connector 270 and prevent it from folding. This situation is as shown in Figure 11B shown.

[0065] When the first end of the locking pin 330 completely leaves the first groove 311, the first blade connector 210 can freely rotate upward - see Figure 11C .

[0066] It should be noted that the user only needs to hold the outer blade part and push it in the folding direction. In the first rotation stage (usually the first 90° of rotation), the second hinge axis 252 will rotate as the active hinge, and then in the subsequent second rotation stage, the first hinge axis 251 automatically becomes the active hinge. In this regard, it does not matter whether the outer blade part or the inner blade part rotates first relative to the central hinge element 240.

[0067] For reverse rotation, to open the folding blades, the user only needs to hold the outer blade part again and push it in the usage direction. First, the first hinge axis 251 automatically becomes the active hinge, causing the first blade connector 210 to remain extended - from Figures 11C to 11B When the first blade connector 210 reaches its extended state defined by a stop block (not shown for simplicity), the second hinge axis 252 becomes active after the locking pin moves.

[0068] Moving the locking pin 330 may require user operation. To assist the user, the folding control device 300 may include a biasing member 340, such as a spring, which is arranged in the chamber 320 or another suitable position, and the biasing member 340 applies a biasing force on the locking pin 330, thereby pressing the locking pin 330 towards the second hinge axis 252. Alternatively or additionally, in a preferred embodiment, the second end of the locking pin 330 has a bevel, and so does the second recess 312, such that the force applied on the second blade connector 270 will force the second end of the locking pin 330 out of the second groove 312, and at the same time the first end of the locking pin 330 enters the first groove 311, so that the second blade connector 270 can rotate further - from Figures 11B to 11A Similarly, in a preferred embodiment, the first end of the locking pin 330 has a bevel, and so does the first groove 311, forcing the first end of the locking pin 330 out of the first groove 311 at the end of the folding operation, from Figure 11A the position in Figure 11B to the position in

[0069] The extended and deployed states of the hinge structure 200 can be restricted and fixed by the first pin hole device and the second pin hole device respectively. The first pin hole device is used to define the extended position of the first blade connector 210 relative to the central hinge element 240, and the second pin hole device is used to define the extended position of the second blade connector 270 relative to the central hinge element 240. This means that before the user folds the blade, he must remove these two pins, and after deploying the blade, he needs to place these pins. In the further elaboration of the present invention, such a fixed arrangement is no longer required because the extended and deployed states of the hinge structure 200 are defined by the stop blocks, and the precise design and position of such stop blocks are not necessary. Such stop blocks can be arranged on the central hinge element, or on the blade connector, or on both. The first such stop block defines the extended position of the first blade connector 210 relative to the central hinge element 240, and the second such stop block defines the extended position of the second blade connector 270 relative to the central hinge element 240. For the user, the advantage of this is that he can start folding the blade without first removing the pins, and he can deploy the blade until the blade reaches the stop block without the need to place any pins. In the operating state, such a pin hole arrangement device is not required to keep the blade deployed because the forces on the blade are sufficient to keep it automatically extended.

[0070] It should be noted that in an embodiment having the folding control device 300, one of the above-mentioned stop blocks can be omitted.

[0071] In summary, the foldable rotor blade includes a hinge element defined by two hinge axes arranged in parallel and two blade portions. Each blade portion is connected to the hinge element so as to hinge relative to the respective hinge axis. The rotor blade has an extended state in which the blade portions are substantially aligned with each other; the rotor blade has a folded state in which each blade portion rotates relative to the hinge element such that the blade portions are substantially parallel to each other. The blade has a chord, and the hinge axis is substantially parallel to the chord. The blade portion has an upper surface and a hinge unit located in the middle of the blade. The upper surfaces face each other in the folded state and are aligned with each other in the extended state.

[0072] Those skilled in the art should be clear that the present invention is not limited to the exemplary embodiments discussed above, but rather several variations and modifications can be made within the scope of the present invention defined by the appended claims. For example, the hinge structure of the present invention can also be applied to fixed-wing aircraft. In addition, a hinge structure 200 of the blade connector connected to the blade portion can be replaced by a blade connector integrated with the blade portion (i.e., the blade portion is provided with hinge portions such as 212 or 272).

[0073] Even if certain features are recited in different dependent claims, the present invention also relates to embodiments that include these common features. Even if certain features have been described in combination with each other, the present invention also relates to embodiments in which one or more of these features are omitted. Features that are not explicitly described as necessary may also be omitted. Any reference signs in the claims shall not be construed as limiting the scope of the claim.

Claims

1. A vehicle (100) provided with a lifting rotor (150) and foldable rotor blades (152, 153), wherein the total number of the rotor blades is two; Each of the rotor blades includes a hinge element (173; 240) defining two hinge axes arranged in parallel, and two blade portions (171, 172), each blade portion (171, 172) being connected to the hinge element (173; 240) to be rotatable relative to its respective hinge axis; Among them, The rotor blades have an extended state, in which the blade portions are substantially aligned with each other; And wherein the rotor blades have a folded state, in which each blade portion rotates relative to the hinge element such that the blade portions are substantially parallel to each other; Wherein the blade has a chord (14), and is characterized in that the hinge axis is substantially parallel to the chord (14); Wherein the hinge element (240) has - A central body (241); - At least one first connecting flange (242), the first connecting flange (242) extending away from the central body (241) in a first direction, and a first cylindrical hole (244) vertically penetrating the first connecting flange (242); - At least one second connecting flange (243), the second connecting flange (243) extending away from the central body (241) in an opposite second direction, and a second cylindrical hole (245) vertically penetrating the second connecting flange (243); Wherein one end of the first blade portion (171) of the blade portions is provided with a hinge portion (212), the hinge portion (212) including at least one connecting flange (213) and a cylindrical hole (214) vertically penetrating the connecting flange (213); Wherein one end of the second blade portion (172) of the blade portions is provided with a hinge portion (272), the hinge portion (272) including at least one connecting flange (273) and a cylindrical hole (274) vertically penetrating the connecting flange (273); And wherein the rotor blade further includes - A first cylindrical hinge axis (251) disposed in the aligned holes (214, 244) of the first blade portion (171) and the hinge element (240); and - A second cylindrical hinge axis (252) disposed in the aligned holes (274, 245) of the second blade portion (172) and the hinge element (240); The vehicle has a body (110) and a main shaft (140) hinged to the body (110); Wherein the lifting rotor (150) includes a rotor hub (151), the rotor hub (151) being mounted on the top end (142) of the main shaft (140) such that the rotation axis of the rotor hub is fixed relative to the main shaft; And the proximal blade portion (171) of each foldable rotor blade is hinged to the rotor hub, wherein the hub hinge axis (154, 155) between the rotor hub (151) and the proximal blade portion (171) is substantially parallel to the chord (14) of the rotor blade; wherein the length of the rotor blade is greater than the length of the vehicle body (110); wherein the flight states of the vehicle are: the main shaft is in a vertical position, the chord planes of the two rotor blades are in a horizontal direction; and wherein the compact state of the vehicle for road travel is: the main shaft (140) is lowered to a horizontal position, the rotation axis of the rotor hub (151) is in a horizontal direction; the proximal blade portion (171) extends from the rotor hub (151) to the rear end of the vehicle body (110) parallel to the main shaft (140); the hub hinge axis (154, 155) extends vertically, the chord (14) of the rotor blade is in a vertical direction.

2. The vehicle according to claim 1, wherein, The extended state of the rotor blade is defined by at least one stop in the hinge element and at least one of the blade portions.

3. The vehicle according to claim 1 or 2, wherein the blade portions (171, 172) have upper surfaces (171u, 172u) and an intermediate hinge element (240), the upper surfaces facing each other in the folded state and being flush with each other in the extended state.

4. The vehicle according to claim 3, further comprising a priority folding control device (300) for ensuring a priority rotation sequence of the first blade portion (171) and the second blade portion (172).

5. The vehicle according to claim 4, wherein the priority folding control device (300) has a first locked state in which the first blade portion (171) is locked in an extended state relative to the hinge element (240) and the second blade portion (172) is allowed to rotate.

6. The vehicle according to claim 4 or 5, wherein the priority folding control device (300) has a second locked state in which the second blade portion (172) is locked in a folded state relative to the hinge element (240) and the first blade portion (171) is allowed to rotate.

7. The vehicle according to claim 6, wherein the hinge element (240) is provided with an axially movable locking pin (330) having a first end and a second end opposite the first end, wherein the first end engages with the first blade portion (171) to lock it, or the second end engages with the second blade portion (172) to lock it.

8. The vehicle according to claim 7, wherein the first end and the second end each have a bevel.

9. The vehicle according to claim 7 or 8, further comprising a biasing member (340) for applying a biasing force on the locking pin (330).

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