Tandem double-rotor structure and unmanned helicopter

Abstract

The utility model provides a tandem type double-rotor structure which comprises a first rotor assembly and a second rotor assembly, the first rotor assembly is arranged at the front end of an unmanned helicopter body, and the second rotor assembly is arranged at the rear end of the unmanned helicopter body; the bottom ends of rotor shafts of the first rotor assembly and the second rotor assembly are connected with the corresponding mounting bases correspondingly, the mounting bases are connected with the fuselage, and the mounting bases have preset forward inclination angles relative to the fuselage. The front rotor wing and the rear rotor wing incline forwards by a certain angle at the same time, so that when the unmanned helicopter flies forwards at a high speed, the helicopter body can be kept horizontal as much as possible, only the front propeller disc and the rear propeller disc incline forwards to generate forward propelling component force, and therefore the windward area of the helicopter body can still be kept minimum; according to the unmanned helicopter, the resistance of the helicopter body during forward flight can be reduced, the windward area of the propeller disc can be smaller, the forward flight resistance can be further reduced, the aerodynamic performance of the unmanned helicopter is improved, and meanwhile the applicability of the unmanned helicopter is improved.

Description

Technical Field

[0001] This utility model relates to the field of unmanned helicopter technology, and in particular to a tandem dual-rotor structure and an unmanned helicopter. Background Technology

[0002] In recent years, with the continuous advancement of technology in various fields, especially flight control, unmanned helicopters have developed rapidly and are increasingly becoming a focus of attention. In the field of unmanned helicopters, a twin-rotor configuration is commonly used, which can be divided into tandem, transverse, and coaxial configurations. The transverse configuration has two rotors distributed on either side of the fuselage, resulting in higher forward drag and is rarely used. The coaxial configuration arranges two rotors rotating in opposite directions on a single rotor shaft, with the rotor disks completely overlapping. This leads to aerodynamic interference between the upper and lower rotors, and the complex control mechanism and special rotor hub increase drag and reduce forward flight efficiency. The tandem configuration is currently the most widely used twin-rotor structure for unmanned helicopters. It has one rotor at the front and one at the rear of the fuselage. In traditional designs, the two rotors are identical but rotate in opposite directions, with a certain degree of overlap in their rotor disks and synchronized rotation phase. Therefore, to prevent the two rotors from rubbing against each other, their rotation phase must be synchronized, requiring a synchronization shaft running through the fuselage. This increases structural complexity and weight.

[0003] Some related technologies also employ a scheme where two rotors are arranged at different heights, one in front of the other. This method allows the two rotors to be staggered in height, preventing them from rubbing against each other even if their rotation phases are not synchronized. Compared to the aforementioned traditional schemes, this eliminates the need for a synchronization shaft, resulting in improved performance. With the further advancements and iterations of unmanned helicopter technology, the requirements for the aerodynamic performance of unmanned helicopters are becoming increasingly stringent, necessitating further improvements. Utility Model Content

[0004] The purpose of this invention is to address the shortcomings of the aforementioned background technology by providing a solution for an unmanned helicopter with a tandem twin-rotor structure arranged at different heights and tilted forward, so as to give the unmanned helicopter better aerodynamic performance.

[0005] To achieve the above objectives, this utility model provides a tandem dual-rotor structure, including a first rotor assembly and a second rotor assembly. The first rotor assembly is disposed at the front end of the unmanned helicopter fuselage, and the second rotor assembly is disposed at the rear end of the unmanned helicopter fuselage.

[0006] Both the first rotor assembly and the second rotor assembly include blades, rotor head, rotor shaft, cyclic pitch control module, and mounting base;

[0007] The bottom ends of the rotor shafts of the first rotor assembly and the second rotor assembly are respectively connected to the corresponding mounting bases. The mounting bases are connected to the fuselage. The mounting bases have a preset forward tilt angle relative to the fuselage, so that the first rotor assembly and the second rotor assembly as a whole have a preset forward tilt angle relative to the fuselage, thereby the propeller disk composed of the blades has a preset forward tilt angle relative to the fuselage.

[0008] Furthermore, both the first rotor assembly and the second rotor assembly have the same forward tilt angle relative to the fuselage.

[0009] Furthermore, the rotor shaft lengths of the first rotor assembly and the second rotor assembly are set to be the same; or,

[0010] The rotor shaft lengths of the first rotor assembly and the second rotor assembly are set to be different.

[0011] Furthermore, the mounting base includes a base body and a plurality of connectors disposed on both sides of the base body. The base body is connected to the bottom end of the rotor shaft, and the connectors are connected to the front or rear end of the fuselage.

[0012] Furthermore, each connector consists of a pair of clamps, one of which is integrally formed or fixedly connected to the base body, and is detachably connected to the other clamp. The front and rear ends of the machine body are provided with connecting shafts, and the clamps are engaged with the connecting shafts. The connecting shafts have a preset forward tilt angle relative to the machine body.

[0013] Furthermore, universal couplings are provided at both the front and rear ends of the machine body. The universal couplings are used to connect the transmission structure in the mounting base with the transmission shaft in the machine body and rotate synchronously.

[0014] Furthermore, the forward tilt angle of both the first rotor assembly and the second rotor assembly is set to 5~10°.

[0015] This utility model also provides an unmanned helicopter, including a fuselage and a tandem dual-rotor structure as described above.

[0016] The above-mentioned solution of this utility model has the following beneficial effects:

[0017] The tandem dual-rotor structure and unmanned helicopter provided by this utility model, by tilting the front and rear rotors forward at a certain angle simultaneously, allows the unmanned helicopter to maintain its fuselage as horizontal as possible during high-speed forward flight. Only the two rotor disks tilt forward to generate forward propulsion, thus minimizing the frontal area of ​​the fuselage and reducing drag during forward flight. Furthermore, the smaller frontal area of ​​the rotor disks further reduces drag, improving the aerodynamic performance of the unmanned helicopter. At the same time, the synchronous forward tilting of the front and rear rotors ensures that the unmanned helicopter can maintain maximum lift during ascent, enhancing its applicability.

[0018] Other beneficial effects of this invention will be described in detail in the following detailed description section. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the tandem twin-rotor structure of this utility model (with hidden blades).

[0020] Figure 2 This is a schematic diagram of the forward tilt angle of this utility model;

[0021] Figure 3 This is a schematic diagram of the mounting base of this utility model;

[0022] Figure 4 This is a schematic diagram of the unmanned helicopter of this utility model (with hidden rotor blades).

[0023] [Explanation of Labels in the Attached Image]

[0024] 1-First rotor assembly; 2-Second rotor assembly; 3-Fuselage; 4-Mounting base; 5-Base; 6-Connector. Detailed Implementation

[0025] To make the technical problems, solutions, and advantages of this utility model clearer, a detailed description will be provided below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model. Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0026] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a locking connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0028] like Figures 1-3 As shown, an embodiment of this utility model provides a tandem dual-rotor structure, including a first rotor assembly 1 and a second rotor assembly 2. The first rotor assembly 1 is located at the front end of the unmanned helicopter fuselage 3, and the second rotor assembly 2 is located at the rear end of the unmanned helicopter fuselage 3. The first rotor assembly 1 includes blades, a rotor head, a rotor shaft, a cyclic pitch control module, etc., which are existing technologies and their specific structures and connections will not be described in detail here. The second rotor assembly 2 has the same structure as the first rotor assembly 1, except that the length of the rotor shaft and associated links of the second rotor assembly 2 is greater than that of the first rotor assembly 1, so that the second rotor assembly 2 and the first rotor assembly 1 form a front-to-back height-reduction layout, achieving the effect mentioned in the background art.

[0029] In this embodiment, both the first rotor assembly 1 and the second rotor assembly 2 include a mounting base 4. The bottom end of the rotor shaft and the periodic pitch control module of the two rotor assemblies are connected to the corresponding mounting base 4, and the mounting base 4 is connected to the fuselage 3. When the fuselage 3 is in a horizontal attitude, the mounting base 4 has a preset tilt angle, which is tilted forward, so that the first rotor assembly 1 and the second rotor assembly 2 as a whole have a preset forward tilt angle relative to the fuselage 3, and thus the propeller disk composed of the blades also has a preset forward tilt angle relative to the fuselage 3.

[0030] By setting the forward tilt angle, the fuselage 3 of the unmanned helicopter can remain as horizontal as possible during high-speed forward flight. Only the two rotor discs tilt forward to generate forward force, thus minimizing the frontal area of ​​the fuselage 3 (typically, the frontal area is smallest when the fuselage 3 is horizontal). This reduces drag during forward flight and achieves higher aerodynamic performance. Furthermore, this configuration in this embodiment allows the unmanned helicopter to maintain the same forward flight speed with a smaller rotor disc tilt angle compared to existing technologies due to the better aerodynamic performance of the fuselage 3. This further reduces the frontal area of ​​the rotor discs and decreases forward drag. These combined effects significantly improve the aerodynamic performance of the unmanned helicopter.

[0031] It should be noted that the forward-tilt configuration of both the front and rear rotors relative to the fuselage 3 in this embodiment requires the first rotor assembly 1 and the second rotor assembly 2 to remain horizontal during vertical takeoff and landing, resulting in a nose-up attitude for the fuselage 3. Maintaining this attitude ensures that both rotor disks remain horizontal, maximizing lift. Therefore, in this embodiment, both the first rotor assembly 1 and the second rotor assembly 2 have the same forward tilt angle relative to the fuselage to ensure they remain horizontal simultaneously, maximizing lift. Compared to configurations where the two rotor assemblies have inconsistent forward tilt angles or only one rotor assembly has a forward tilt angle, this configuration offers greater adaptability to different operating conditions.

[0032] It should be noted that when both the first rotor assembly 1 and the second rotor assembly 2 have a forward tilt angle relative to the fuselage, and such forward tilt angles are set equally in this embodiment, the rotor shafts are also tilted forward relative to the fuselage. Therefore, even with the front-to-back height adjustment, the blades of the first rotor assembly 1 and the second rotor assembly 2 may still interfere with each other. Based on this, it is necessary to readjust the height of the front and rear rotor shafts, or not use the front-to-back rotor shaft height adjustment at all, as long as the two rotors can be prevented from rubbing against each other. Those skilled in the art can make adjustments based on the actual situation.

[0033] In this embodiment, the mounting base 4 includes a base body 5 and connectors 6 disposed on both sides of the base body 5. The base body 5 provides rotational support for the bottom end of the rotor shaft and enables the rotor shaft to be connected to the drive shaft within the fuselage 3. Additionally, the base body 5 supports some components of the periodic pitch control module. The connectors 6 are in the form of clamps, with multiple connectors arranged on both sides of the base body 5. Each connector 6 consists of a pair of clamps. For each connector 6, one clamp is integrally formed or fixedly connected to the base body 5, while the other clamp is detachably connected. The pair of clamps are secured by bolt holes at the edge of the clamps and mounting bolts. For the fuselage 3, connecting shafts are provided at both its front and rear ends. The connectors 6 engage with the connecting shafts, fixing the mounting base 4 to both ends of the fuselage 3. Therefore, in this embodiment, the connecting shafts at the front and rear ends of the fuselage 3 are tilted forward at a predetermined angle relative to the fuselage 3, so that after the connectors 6 of the two mounting bases 4 are connected to the connecting shafts, the first rotor assembly 1 and the second rotor assembly 2 can tilt forward at a predetermined angle.

[0034] As can be seen from the above, the first rotor assembly 1 and the second rotor assembly 2 provided in this embodiment are both fixed forward tilt angles, which can ensure high aerodynamic performance when the unmanned helicopter is flying forward and maintain a pitched-up attitude to maximize lift during vertical ascent. In other embodiments, an angle-adjustable method can also be used, that is, an angle adjustment mechanism can be set to adjust the angle of the mounting base 4 relative to the fuselage 3. It is understood that this angle adjustment mechanism is relatively complex, increasing the complexity of the internal structure and the weight, etc. Therefore, the preferred embodiment still uses the first rotor assembly 1 and the second rotor assembly 2 with fixed forward tilt angles, which can meet the requirements of high aerodynamic performance.

[0035] In addition, since both the front and rear mounting bases 4 are tilted relative to the fuselage 3, and the transmission shaft inside the fuselage 3 that connects to the engine is usually arranged parallel to the fuselage 3, universal couplings need to be further installed at the front and rear ends of the fuselage 3. Through the universal couplings, the transmission structure inside the mounting base 4 can be connected to the transmission shaft and rotate synchronously to achieve the purpose of driving the blade to rotate.

[0036] In one specific embodiment of this example, the forward tilt angle of both the first rotor assembly 1 and the second rotor assembly 2 is set to 5~10°, for example, it can be set to 7°. After actual debugging, this can bring about a better aerodynamic performance improvement effect.

[0037] Based on the same innovative concept, this embodiment also provides an unmanned helicopter, such as Figure 4As shown, the helicopter includes a fuselage 3 and the aforementioned first rotor assembly 1 and second rotor assembly 2, located at the front and rear ends of the fuselage 3. This type of unmanned helicopter can be either gasoline-powered or electric, both of which improve aerodynamic performance. In this embodiment, regardless of whether it is gasoline-powered or electric, the engine is located in the middle of the fuselage 3 to ensure a more even weight distribution and thus better flight stability. For gasoline-powered helicopters, a gearbox is typically also required, which is also located in the middle of the fuselage 3. The drive shaft is located at the top of the fuselage 3 and extends to both ends along the length of the fuselage 3. The gearbox and drive shaft are connected by a transmission structure.

[0038] In summary, the tandem dual-rotor structure and unmanned helicopter provided in this embodiment, by tilting the front and rear rotors forward at a certain angle simultaneously, allows the fuselage 3 to remain as horizontal as possible during high-speed forward flight. Only the two rotor disks tilt forward to generate forward propulsion, thus minimizing the frontal area of ​​the fuselage 3 and reducing drag during forward flight. Furthermore, the smaller frontal area of ​​the rotor disks further reduces drag, improving the aerodynamic performance of the unmanned helicopter. At the same time, the synchronous forward tilting of the front and rear rotors ensures that the unmanned helicopter can maintain maximum lift during ascent, enhancing its applicability.

[0039] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0040] The above embodiments are merely illustrative of several implementation methods of this application, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A tandem twin-rotor structure, characterized in that, It includes a first rotor assembly and a second rotor assembly, wherein the first rotor assembly is disposed at the front end of the unmanned helicopter fuselage and the second rotor assembly is disposed at the rear end of the unmanned helicopter fuselage; Both the first rotor assembly and the second rotor assembly include blades, rotor head, rotor shaft, cyclic pitch control module, and mounting base; The bottom ends of the rotor shafts of the first rotor assembly and the second rotor assembly are respectively connected to the corresponding mounting bases. The mounting bases are connected to the fuselage. The mounting bases have a preset forward tilt angle relative to the fuselage, so that the first rotor assembly and the second rotor assembly as a whole have a preset forward tilt angle relative to the fuselage, thereby the propeller disk composed of the blades has a preset forward tilt angle relative to the fuselage.

2. The tandem twin-rotor structure according to claim 1, characterized in that, Both the first rotor assembly and the second rotor assembly have the same forward tilt angle relative to the fuselage.

3. The tandem twin-rotor structure according to claim 1, characterized in that, The rotor shaft lengths of the first rotor assembly and the second rotor assembly are set to be the same; or, The rotor shaft lengths of the first rotor assembly and the second rotor assembly are set to be different.

4. The tandem twin-rotor structure according to claim 1, characterized in that, The mounting base includes a base body and multiple connectors disposed on both sides of the base body. The base body is connected to the bottom end of the rotor shaft, and the connectors are connected to the front or rear end of the fuselage.

5. A tandem twin-rotor structure according to claim 4, characterized in that, Each connector consists of a pair of clamps, one of which is integrally or fixedly connected to the base and detachably connected to the other clamp. The front and rear ends of the body are provided with connecting shafts, and the clamps engage with the connecting shafts. The connecting shafts have a preset forward tilt angle relative to the body.

6. The tandem twin-rotor structure according to claim 1, characterized in that, Universal couplings are provided at both the front and rear ends of the machine body. The universal couplings are used to connect the transmission structure in the mounting base with the transmission shaft in the machine body and rotate synchronously.

7. A tandem twin-rotor structure according to any one of claims 1-6, characterized in that, The forward tilt angle of both the first rotor assembly and the second rotor assembly is set to 5~10°.

8. An unmanned helicopter, characterized in that, It includes the fuselage and a tandem twin-rotor structure as described in any one of claims 1-6.

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