A single pin blade root for facilitating folding of a rotor

Abstract

The present application belongs to the technical field of helicopter rotor system, and is a single-pin blade root facilitating folding of rotor, comprising at least two root girders, the root girders extending from the blade root, each root girder being arranged in parallel and spaced apart in the span direction of the blade root, a through hole with coincident axis being provided on each root girder, and a root bushing being arranged in the through hole; the blade pin is connected to the hub by passing through all the root bushings. The blade root configuration of the present application not only has the basic function of transmitting the load of the blade to the hub, but also facilitates folding of the rotor, reduces the number of additional components and additional weight caused by automatic folding of the rotor, and good folding effect can be obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of helicopter rotor systems and relates to a folding structure design of a helicopter rotor system, in particular to a single-pin blade root that facilitates rotor folding. Background Art

[0002] Folding a helicopter's rotors when parked significantly reduces the space required. Therefore, rotor folding technology is a key area of ​​development in helicopter rotor technology. Rotor folding is achieved by manually or motor-drivenly rotating the blades around their roots to a certain angle. Typically, motor-driven blade rotation provides a highly automated method for rotor folding. Using a blade root configuration that facilitates rotor folding simplifies the overall rotor folding system.

[0003] At present, the configurations of the rotor blade roots are diverse, including parallel double-pin structures, comb-shaped joint structures, etc. Regardless of the configuration of these blade roots, they can all achieve the basic function of transferring the blade load to the hub. However, these blade root configurations are usually double-pin or multi-pin structures, which are insufficient in achieving the rotor folding function. If manual folding is to be achieved, it is necessary to manually loosen the connection structure between the blade and the hub (release the blade). Figure 1 The connection between the middle bushing A and the hub is only connected by a pin, and then folded. This folding method is inefficient. If motor-driven automatic folding is to be achieved, an additional adapter is required. The design of the adapter to achieve the rotor folding function brings a large weight penalty and reduces the reliability of the entire system. Therefore, when designing a rotor system with folding requirements, the interface between the blade root, the hub, and the folding mechanism must be considered when designing the blade root configuration. This design simplifies the connection between the blade and other components. Summary of the Invention

[0004] In order to solve the above problems, the present invention proposes a single-pin blade root that facilitates rotor folding. This blade root configuration not only has the basic function of transferring the blade load to the hub, but also facilitates the realization of the rotor folding function, and can greatly reduce the structural weight while achieving automatic folding.

[0005] The technical solution of the present invention:

[0006] A single-pin blade root for facilitating rotor folding comprises at least two root beams extending from the blade root, each root beam being arranged in parallel and spaced apart in the span direction of the blade root, all the root beams being provided with a through hole with coinciding axes, and a root bushing being installed in the through hole; the blade pin passes through all the root bushings and is connected to the hub.

[0007] Further, the included angle between the axial direction of the root bushing and the chord line of the blade is less than 30°.

[0008] Further, the beam block is installed at the end of the root beam, and the end of the beam block is provided with a folding locking groove matched with the folding mechanism locking pin.

[0009] Further, the folding locking groove is a semicircular groove.

[0010] Further, the blade pin can rotate in the root bushing, and the root bushing is fixed relative to the root beam and the beam block.

[0011] Further, the middle section of the root bushing is a cylindrical surface, both ends of the root bushing are provided with a shoulder with a spline structure, the middle section of the root bushing is arranged in the through hole of the root beam, the connection part of the beam block and the root beam is provided with a spline matched with the shoulder of the root bushing, and the spline of the beam block is connected with the spline of the shoulder of the root bushing. This structure is easy to process, only the corresponding splines need to be designed on the outer sides of the two sides of the beam block, and then the torque of the root bushing is transmitted to the root of the beam through the fixed connection of the beam block and the root of the beam.

[0012] Further, the area of the through hole of the root beam is greater than the maximum range area of the shoulder of the root bushing, and the end of the through hole of the root beam has an arc matched with the cylindrical surface of the middle section of the root bushing; the beam filler is inserted into the other space of the through hole of the root beam.

[0013] Alternatively, the outer side of the root bushing is a spline structure, the root bushing is arranged at the connection part of the root beam and the beam block, the end of the root beam has a half internal spline matched with the root bushing, the front end of the beam block has a half internal spline matched with the root bushing, the root beam and the beam block are connected to form a complete internal spline matched with the root bushing, and the root bushing is arranged in the complete internal spline. Under this structure, the root bushing has the best effect of transmitting the torsional torque, but the machining requirements of the root beam, the beam block and the root bushing are higher.

[0014] The beneficial effects of the present application are as follows:

[0015] The single-pin blade root structure of the application has two root bushing axes coinciding to form a single-pin configuration; the folding locking groove is a semicircular structure, facilitating the locking and unlocking of the folding mechanism; the small groove / key of the blade root bushing shoulder is connected with the external folding mechanism, used for transmitting the folding load. In the helicopter flight state, the blade root folding locking groove is connected and locked with the folding mechanism, the bending moment of the blade up and down flapping is transmitted through the folding locking groove and the two root bushings, at the same time, the bending moment of the blade forward and backward oscillation and the torque required by the rotor rotation are transmitted through the two root bushings, so as to realize the basic function of transmitting the blade load to the hub. In the helicopter parking state, after the connection between the blade folding locking groove and the folding mechanism is released, the folding mechanism drives the small groove / key of the blade root bushing shoulder to rotate around the bushing axis, realizing the folding of the blade.

[0016] In summary, the blade root configuration of the application not only has the basic function of transmitting the blade load to the hub, but also facilitates the realization of the rotor folding function, reduces the number of additional components and additional weight brought by the automatic folding of the rotor, and can obtain good folding effect. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a schematic diagram of a conventional blade root structure of the background art;

[0018] Figure 2 is a schematic diagram of the overall structure of the blade root of the embodiment of the application;

[0019] Figure 3 is an exploded view of a root structure of the embodiment of the application;

[0020] Among them, 1—root girder, 2—girder filler, 3—root bushing, 4—girder plug. DETAILED DESCRIPTION

[0021] This part is an embodiment of the application, used to explain and illustrate the technical solution of the application. In the case of no conflict, the embodiments of the application and the features in the embodiments can be combined with each other.

[0022] In the description of the present application, it needs to be understood that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship as the orientation or positional relationship given by the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or cases referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second" and the like are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implying the number of the technical features indicated. Therefore, the features defined with "first", "second" and the like can be explicitly or implicitly included. In the description of the present application, unless otherwise stated, the meaning of "a plurality of" is two or more.

[0023] In the description of the present application, it needs to be understood that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be interpreted broadly, for example, it can be fixed connection, or detachable connection or integrated connection; it can be mechanical connection, or point connection; it can be direct connection, or indirect connection through intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0024] A single-pin blade root facilitating folding of rotor blades, comprising at least two root girders 1 extending from the blade root, each root girder being arranged in parallel and spaced apart in the spanwise direction of the blade root, each root girder 1 being provided with a through hole with coincident axis, and a root bushing 3 being arranged in the through hole; the blade pin being arranged by passing through all the root bushings 3 and being connected to the hub.

[0025] The included angle between the axial direction of the root bushing 3 and the chord line of the blade is less than 30°.

[0026] Further comprising a girder block 4 arranged at the end of the root girder 1, and the girder block 4 is provided with a folding locking groove at the end for locking the folding mechanism locking pin.

[0027] The folding locking groove is a semicircular groove.

[0028] The blade pin can rotate in the root bushing 3, and the root bushing 3 is fixed relative to the root girder 1 and the girder block 4.

[0029] The middle section of the root bushing 3 is a cylindrical surface, both ends of the root bushing 3 are provided with a shoulder with a spline structure, the middle section of the root bushing 3 is arranged in the through hole of the root beam 1, the connecting part of the beam block 4 and the root beam 1 is provided with a spline matched with the shoulder of the root bushing 3, and the spline of the beam block 4 is connected with the spline shoulder of the root bushing 3. The structure is easy to process, only the corresponding splines need to be designed on the outer sides of the two sides of the beam block 4, then the torque of the root bushing 3 is transmitted to the root beam 1 through the fixed connection of the beam block 4 and the root beam 1.

[0030] The through hole area of the root beam 1 is greater than the maximum range area of the shoulder of the root bushing 3, and the end of the through hole of the root beam 1 has an arc matched with the cylindrical surface of the middle section of the root bushing 3; the beam filling block 2 is further included, and the beam filling block 2 is inserted into the other space of the through hole of the root beam 1.

[0031] Alternatively, the outer side of the root bushing 3 is a spline structure, the root bushing 3 is arranged at the connecting part of the root beam 1 and the beam block 4, the end of the root beam 1 has a half inner spline matched with the root bushing 3, the front end of the beam block 4 has a half inner spline matched with the root bushing 3, the root beam 1 and the beam block 4 are connected to form a complete inner spline matched with the root bushing 3, and the root bushing 3 is arranged in the complete inner spline. The effect of transmitting the torsional torque of the root bushing 3 is best under this structure, but the processing requirements of the root beam 1, the beam block 4 and the root bushing 3 are higher.

[0032] An embodiment of the present application will be described below with reference to the drawings.

[0033] As shown in Figure 1 The paddle root structure of the present application comprises a root beam 1, a beam filling block 2, a root bushing 3 and a beam block 4.

[0034] The root beam 1 of the present application is a composite material beam, which is the main load-bearing member of the paddle root, and there are two beams, each of which extends to the inside of the paddle after winding one root bushing 3;

[0035] The beam filling block 2 of the present application is made into a prefabricated part before the root beam 1 is formed, and plays a supporting role when the root beam 1 is formed, and can be made of composite material or rubber;

[0036] The root bushing 3 of the application is used to transfer the load of the root beam 1 to the blade pin, and is of double-shoulder type, and is bonded to the beam when the root beam is of type 1. The axes of the two bushing bores coincide, and the included angle with the blade chord is less than 30°. The shoulders at both ends of the bushing are provided with small grooves / keys, and a part of the small grooves / keys forms a mating surface with the small grooves / keys of the beam block, and bears a part of the load transferred by the beam block 4. Another part of the small grooves / keys cooperates with the driving device of the folding system to transfer the driving torque of the driving mechanism, and drives the blade to rotate around the root; the design of the key is to better fix the beam block, and on the other hand, it can cooperate with other mechanisms to transfer the rotating torque

[0037] The root of each beam is provided with a set of beam blocks 4, which can be made of composite material or metal. Each set of beam blocks 4 can be divided into two blocks, and the inner cavity of the beam block 4 is consistent with the shape of the root beam, and is bonded to the root beam to form a secondary shape. The beam block 4 is provided with a small groove / key for cooperation with the bushing. The other end of the beam block is provided with a folding locking groove (half circle and whole circle are available, and the half circle design is more flexible, and the locking pin can be moved forward and backward to lock and unlock), which is used to cooperate with the locking pin of the folding mechanism.

[0038] The working principle of the blade root configuration of the application is as follows: in the flight state of the helicopter, the axis of the blade root bushing 3 bore is close to the horizontal direction, and the folding locking groove of the beam block 4 is connected and locked with the locking pin of the folding system, at this time, the hub transfers the torque required by the blade rotation to the blade root through the front and rear blade root bushings 3; the bending moment of the blade in the forward and backward swing direction in the rotation plane is transmitted to the hub through the front and rear blade root bushings 3; the bending moment of the blade in the up and down flap direction in the vertical rotation plane is transmitted to the hub and the folding mechanism through the blade root bushing 3 and the folding locking pin. In the stop state, when the rotor starts to fold, first, the blade pitch is adjusted to the highest or lowest pitch, at this time, the axis of the blade root bushing 3 bore is close to the vertical direction; second, the locking pin of the folding system exits the folding locking groove of the beam block 4; third, the driving mechanism of the folding system drives the blade to rotate around the root through the small groove / key of the blade root bushing 3, and the folding of the rotor is realized.

[0039] The axes of the two root bushing bores coincide, and are of single-pin type, and the angle between the axis of the bore and the blade chord is less than 30°;

[0040] The root bushing is of double-shoulder type, and the key groove is formed on the shoulder to form a small groove / key;

[0041] Each set of beam blocks is divided into two blocks, and is bonded to the root beam to form a secondary shape, and the cooperation part of the beam block with the blade root bushing is provided with a small groove / key, and the small groove / key of the beam block cooperates with the small groove / key of the blade root bushing;

[0042] The end of the beam block has a round groove for cooperating with the locking pin of the folding mechanism.

[0043] The above merely describes specific embodiments of the present application, and the detailed description is not exhaustive of conventional technology. However, the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. The protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A single pin blade root facilitating folding of a rotor, characterized in that, The invention relates to a blade root structure, comprising at least two root beams (1) extending from the blade root, each root beam being arranged in parallel and spaced apart in the spanwise direction of the blade root, each root beam (1) being provided with a through hole with an axis of alignment, a root bushing (3) being arranged in the through hole, a blade pin being arranged to pass through all root bushings (3) and being connected to the hub, a beam plug (4) being arranged at the end of the root beam (1), the beam plug (4) being provided with a folding locking groove for locking the folding mechanism pin, the blade pin being rotatable in the root bushing (3), the root bushing (3) being fixed relative to the root beam (1) and the beam plug (4), the middle section of the root bushing (3) being a cylindrical surface, the two ends of the root bushing (3) being provided with a shoulder with a spline structure, the middle section of the root bushing (3) being arranged in the through hole of the root beam (1), the connection between the beam plug (4) and the root beam (1) being provided with a spline for matching the shoulder of the root bushing (3), the spline of the beam plug (4) being connected with the spline of the shoulder of the root bushing (3), the area of the through hole of the root beam (1) being larger than the maximum area of the shoulder of the root bushing (3), the end of the through hole of the root beam (1) having an arc for matching the cylindrical surface of the middle section of the root bushing (3), a beam filler (2) being arranged in the other space of the through hole of the root beam (1).

2. A single pin blade root for facilitating folding of a rotor blade as defined in claim 1, characterized in that The angle between the axial direction of the root bushing (3) and the chord line of the blade is less than 30°.

3. A single pin blade root for facilitating folding of a rotor blade as defined in claim 1, wherein, The folding locking groove is a semicircular groove.

4. A single pin blade root for facilitating folding of a rotor according to claim 1, wherein, The outer side of the root bushing (3) is provided with a spline structure, the root bushing (3) being arranged at the connection between the root beam (1) and the beam plug (4), the end of the root beam (1) having a half internal spline for matching the root bushing (3), the front end of the beam plug (4) having a half internal spline for matching the root bushing (3), the root beam (1) and the beam plug (4) being connected to form a complete internal spline for matching the root bushing (3), the root bushing (3) being arranged in the complete internal spline.

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