Helicopter propeller hub pitch changing mechanism and assembling method thereof

Abstract

The invention belongs to the field of helicopter structural component design, and particularly relates to a helicopter propeller hub pitch changing mechanism and an assembling method thereof. The variable pitch mechanism comprises a tension and torsion bar and an elastic bearing, the tension and torsion bar comprises an inner layer tension and torsion bar girder, an outer layer tension and torsion bar girder, a blade end neck bush, a blade end outer side cover plate, a blade end outer bush, bolts and nuts, a blade end connecting piece, a propeller hub end outer bush, a propeller hub end neck bush and a propeller hub end outer side cover plate, and the tension and torsion bar and the elastic bearing are combined. The torsion capacity of the tension-torsion strip and the elastic bearing is integrated, so that the torsion capacity is higher; and the pulling and twisting strip is arranged in the elastic bearing, so that the space can be effectively saved.

Description

Technical Field

[0001] The present invention belongs to the field of helicopter structural component design, and particularly relates to a helicopter hub pitch-changing mechanism and an assembly method thereof. Background Art

[0002] When a helicopter rotor blade is working, it needs to twist along the blade pitch axis to complete the pitch-changing movement. Currently, there are various ways to achieve the pitch-changing movement of the blade in a helicopter.

[0003] An articulated rotor can enable the blade to perform a twisting movement through a pitch-changing hinge. A tension-torsion bar is a commonly used structure in a helicopter to achieve blade pitch change, and it replaces the pitch-changing hinge of the rotor through its own deformation. A bearingless tail rotor achieves the pitch-changing movement of the blade through the torsional deformation of a flexible beam. However, these several structures also have their own deficiencies. An articulated rotor often has a large weight. The traditional composite tension-torsion bar and metal tension-torsion bar have limited torsional ability and are not suitable for a tiltrotor with a large blade pitch range. The deformation ability of the flexible beam is also limited and is not suitable for the case of a large blade pitch change. Summary of the Invention

[0004] Object of the Invention: To provide a helicopter hub pitch-changing mechanism and an assembly method thereof, so as to achieve a large-angle torsional pitch change of the blade.

[0005] Technical Solution:

[0006] A helicopter hub pitch-changing mechanism includes: a tension-torsion bar and an elastic bearing 9. The tension-torsion bar includes: an inner-layer tension-torsion bar girder 1, an outer-layer tension-torsion bar girder 6, a blade-end inner bushing 2, a blade-end outer cover plate 4, a blade-end outer bushing 7, bolts and nuts 10, a blade-end connecting piece 11, a hub-end outer bushing 8, a hub-end inner bushing 3, and a hub-end outer cover plate 5. Among them,

[0007] The inner-layer tension-torsion bar girder 1 and the outer-layer tension-torsion bar girder 6 are composed of a plurality of strip-shaped structures with both ends turned outwards; the end faces of the blade-end inner bushing 2, the hub-end inner bushing 3, the blade-end outer bushing 7, and the hub-end outer bushing 8 are provided with a plurality of evenly distributed radial card slots;

[0008] Both ends of the inner-layer tension-torsion bar girder 1 are placed in the card slots of the blade-end inner bushing 2 and the hub-end inner bushing 3, and the blade-end inner bushing 2 and the hub-end inner bushing 3 are respectively connected to the blade-end outer cover plate 4 and the hub-end outer cover plate 5;

[0009] The outer-layer tension-torsion bar girder 6 is placed in the card slots of the blade-end outer bushing 7 and the hub-end outer bushing 8, and the blade-end outer bushing 7 and the hub-end outer bushing 8 are respectively assembled and connected to the blade-end inner bushing 2 and the hub-end inner bushing 3 with bolts. The obtained structure is passed through the elastic bearing 9 and the elastic bearing 9 is connected to the hub-end outer bushing 8. The blade-end connecting piece 11 is connected to the blade-end outer bushing 7, and the blade-end connecting piece 11 is connected to the blade.

[0010] Furthermore, the inner layer tension-torsion bar girder 1 and the outer layer tension-torsion bar girder 6 are glass fiber reinforced resin matrix composites.

[0011] Furthermore, the width of the card slot gradually increases radially outwards.

[0012] Furthermore, the inner layer tension-torsion bar girder 1 is obtained by curing through a compression molding process.

[0013] Furthermore, the blade tip connecting piece 11 and the blade tip outer bushing 7 are connected by bolts.

[0014] Furthermore, the inner layer tension-torsion bar girder 1 and the outer layer tension-torsion bar girder 6 are composed of a plurality of strip-shaped structures with both ends turned outwards, and rubber is filled between each strip-shaped structure.

[0015] Furthermore, the widths of the strip-shaped structures of the inner layer tension-torsion bar girder 1 and the outer layer tension-torsion bar girder 6 are the same and evenly distributed.

[0016] Furthermore, the maximum size at the blade tip of the inner layer tension-torsion bar girder 1 and the outer layer tension-torsion bar girder 6 is smaller than the inner diameter of the elastic bearing 9.

[0017] An assembly method for a pitch change mechanism of a helicopter hub, comprising:

[0018] Step 1: Cure the strip-shaped structures of the inner layer tension-torsion bar girder 1 and the outer layer tension-torsion bar girder 6 through a compression molding process;

[0019] Step 2: Respectively place each strip-shaped structure into the card slots of the blade tip inner bushing 2 and the hub end inner bushing 3, as well as the card slots of the blade tip outer bushing 7 and the hub end outer bushing 8;

[0020] Step 3: Vulcanize and fill rubber between each strip-shaped structure;

[0021] Step 4: Respectively connect the blade tip inner bushing 2 and the hub end inner bushing 3 with the blade tip outer cover plate 4 and the hub end outer cover plate 5;

[0022] Step 5: Respectively assemble and connect the blade tip outer bushing 7 and the hub end outer bushing 8 with the blade tip inner bushing 2 and the hub end inner bushing 3 together using bolts;

[0023] Step 6: Pass the structure obtained in Step 5 through the elastic bearing 9 and connect the elastic bearing 9 with the hub end outer bushing 8, and connect the blade tip connecting piece 11 with the blade tip outer bushing 7.

[0024] Beneficial effects:

[0025] (1) The pitch-changing mechanism of the hub provided by the present invention has a stronger torsional ability because it adopts a configuration combining a tension-torsion bar and an elastic bearing, integrating the torsional capabilities of the tension-torsion bar and the elastic bearing.

[0026] (2) For the pitch-changing mechanism of the hub provided by the present invention, placing the tension-torsion bar inside the elastic bearing can effectively save space. Description of the Drawings

[0027] Figure 1 Structural diagram of the inner ring tension-torsion bar girder;

[0028] Figure 2 Structural diagram of the inner lining bushing at the blade end;

[0029] Figure 3 Structural diagram of the inner lining bushing at the hub end;

[0030] Figure 4 Structural diagram of the outer cover plate at the blade end;

[0031] Figure 5 Structural diagram of the outer cover plate at the hub end;

[0032] Figure 6 Structural diagram of the outer ring tension-torsion bar girder;

[0033] Figure 7 Structural diagram of the outer lining bushing at the blade end;

[0034] Figure 8 Structural diagram of the outer lining bushing at the hub end;

[0035] Figure 9 Structural diagram of the elastic bearing;

[0036] Figure 10 Structural diagram of the connecting piece at the blade end;

[0037] Figure 11 Assembly flow chart of the pitch-changing mechanism of the hub;

[0038] Among them, the inner layer tension-torsion bar girder 1, the inner lining bushing 2 at the blade end, the inner lining bushing 3 at the hub end, the outer cover plate 4 at the blade end, the outer cover plate 5 at the hub end, the outer layer tension-torsion bar girder 6, the outer lining bushing 7 at the blade end, the outer lining bushing 8 at the hub end, the elastic bearing 9, the bolt and nut 10, and the connecting piece 11 at the blade end. Detailed Embodiment

[0039] To make the purpose, technical solutions, and advantages of the present application more clear, the following will describe the technical solutions in the embodiments of the present application in more detail in conjunction with the drawings in the embodiments of the present application. In the drawings, the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. The described embodiments are part of the embodiments of the present application, not all of the embodiments. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present application, and should not be construed as limiting the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application. The following will describe the embodiments of the present application in detail in conjunction with the drawings.

[0040] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "center", "axial direction", "vertical", "upper", "lower", "upper end", "bottom end", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the scope of protection of the present invention.

[0041] Such as Figures 1-11 , an efficient helicopter hub pitch-changing mechanism includes two parts: a tension-torsion bar and an elastic bearing 9. The tension-torsion bar part includes: an inner-layer tension-torsion bar girder 1, an outer-layer tension-torsion bar girder 6, a blade-end inner bushing 2, a blade-end outer cover plate 4, a blade-end outer bushing 7, bolts and nuts 10, a blade-end connecting member 11, a hub-end outer bushing 8, a hub-end inner bushing 3, and a hub-end outer cover plate 5. Each part is as shown in the attached Figure 1 shown, and the structural assembly flow chart is as shown in the attached Figure 2 shown. The blade-end connecting member 11 and the elastic bearing 9 can be respectively connected to the blade structure and the hub structure.

[0042] The inner-layer tension-torsion bar girder 1 and the outer-layer tension-torsion bar girder 6 are composed of a plurality of strip-shaped structures with turned-out ends at both ends;

[0043] The end faces of the blade-end inner bushing 2, the hub-end inner bushing 3, the blade-end outer bushing 7, and the hub-end outer bushing 8 are provided with a plurality of evenly distributed radial card slots.

[0044] The inner-layer tension-torsion bar girder 1 and the outer-layer tension-torsion bar girder 6 are glass fiber reinforced resin-based composite materials and are one of the main load-bearing structures of the tension-torsion bar assembly. The inner-layer tension-torsion bar girder 1 can be obtained by curing through a compression molding process. Then, the two ends of the inner-layer tension-torsion bar girder 1 are placed into the blade-end inner bushing 2 and the hub-end inner bushing 3 through the card slots, and the blade-end inner bushing 2 and the hub-end inner bushing 3 are respectively assembled with the blade-end outer cover plate 4 and the hub-end outer cover plate 5.

[0045] The card slot gradually increases in radial outward width.

[0046] In the same way, the outer pull-twist bar girder 6 is placed into the blade tip outer bushing 7 and the hub end outer bushing 8 through the card slot, and the blade tip outer bushing 7 and the hub end outer bushing 8 are respectively assembled and connected to the blade tip inner bushing 2 and the hub end inner bushing 3 using bolts. The obtained structure is passed through the elastic bearing 9, and the elastic bearing 9 is connected to the hub end outer bushing 8. Then, the blade tip connecting member 11 is connected to the blade tip outer bushing 7, which can be fixed by using the bolt connection method, and the blade tip connecting member 11 can be connected to the blade structure.

[0047] The pitch-changing mechanism of the helicopter hub adopts a configuration that combines a pull-twist bar and an elastic bearing. By utilizing the torsional functions of both the elastic bearing and the pull-twist bar, the hub has a relatively high torsional pitch-changing ability.

[0048] The cross-section of the pull-twist bar girder is circular and contains at least one circle of load-bearing structure. When there are two or more circles, each circle can achieve the torsional function.

[0049] The inner and outer pull-twist bar girders are made of composite materials with relatively high tensile strength.

[0050] The inner pull-twist bar girder 1 is fitted with the blade tip inner bushing 2 and the hub end inner bushing 3 through their shapes and the bonding process is used to ensure the connection strength.

[0051] The outer pull-twist bar girder 6 is fitted with the blade tip outer bushing 7 and the hub end outer bushing 8 through their shapes and the bonding process is used to ensure the connection strength.

[0052] There is a bolt connection method, and mechanical positioning can be adopted to ensure the stable cooperation of each part.

[0053] The elastic bearing is composed of rubber and metal materials and can achieve the functions of torsion and pressure bearing.

[0054] The inner and outer pull-twist bar girders 6 can adopt thermoplastic resin materials to improve the mechanical properties of the materials.

[0055] Resin is allowed to be filled between the composite strips in the inner pull-twist bar girder 1 to ensure firm bonding between the resin and the glass fiber composite strips.

[0056] Resin is allowed to be filled between the composite strips in the outer pull-twist bar girder 6 to ensure firm bonding between the resin and the glass fiber composite strips.

[0057] An assembly method for a pitch-changing mechanism of a helicopter hub, comprising:

[0058] Step 1: Cure the strip structures of the inner pull-twist bar girder 1 and the outer pull-twist bar girder 6 through a compression molding process.

[0059] Step 2: Place each strip structure into the card slots of the blade end inner bushing 2 and the hub end inner bushing 3, as well as into the card slots of the blade end outer bushing 7 and the hub end outer bushing 8;

[0060] Step 3: Vulcanize and fill rubber between each strip structure;

[0061] Step 4: Connect the blade end inner bushing 2 and the hub end inner bushing 3 to the blade end outer cover plate 4 and the hub end outer cover plate 5 respectively;

[0062] Step 5: Assemble and connect the blade end outer bushing 7 and the hub end outer bushing 8 to the blade end inner bushing 2 and the hub end inner bushing 3 respectively using bolts;

[0063] Step 6: Pass the structure obtained in Step 5 through the elastic bearing 9 and connect the elastic bearing 9 to the hub end outer bushing 8, and connect the blade end connecting member 11 to the blade end outer bushing 7.

[0064] As described above, it is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any change or replacement that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claimed rights.

Claims

1. A variable pitch mechanism for a helicopter hub, characterized in that, Comprising: A tension-torsion bar and an elastic bearing. The tension-torsion bar includes: an inner tension-torsion bar girder, an outer tension-torsion bar girder, a blade-end inner bushing, a blade-end outer side cover plate, a blade-end outer bushing, a bolt and nut, a blade-end connecting member, a hub-end outer bushing, a hub-end inner bushing, and a hub-end outer side cover plate. Among them, The inner tension-torsion bar girder and the outer tension-torsion bar girder are composed of multiple strip-shaped structures with both ends turned outwards; multiple evenly distributed radial card slots are provided on the end faces of the blade-end inner bushing, the hub-end inner bushing, the blade-end outer bushing, and the hub-end outer bushing; Both ends of the inner tension-torsion bar girder are placed in the card slots of the blade-end inner bushing and the hub-end inner bushing, and the blade-end inner bushing and the hub-end inner bushing are respectively connected to the blade-end outer side cover plate and the hub-end outer side cover plate; The outer tension-torsion bar girder is placed in the card slots of the blade-end outer bushing and the hub-end outer bushing, and the blade-end outer bushing and the hub-end outer bushing are respectively assembled and connected to the blade-end inner bushing and the hub-end inner bushing using bolts. The obtained structure is passed through the elastic bearing and the elastic bearing is connected to the hub-end outer bushing. The blade-end connecting member is connected to the blade-end outer bushing, and the blade-end connecting member is connected to the blade.

2. The pitch-changing mechanism of the helicopter hub according to claim 1, characterized in that The inner tension-torsion bar girder and the outer tension-torsion bar girder are glass fiber reinforced resin matrix composites.

3. The pitch change mechanism of the helicopter hub according to claim 1, characterized in that, The width of the card slot gradually increases radially outwards.

4. The helicopter hub pitch-changing mechanism according to claim 1, characterized in that, The inner tension-torsion bar girder is obtained by curing through a compression molding process.

5. The pitch change mechanism of the helicopter hub according to claim 1, characterized in that The blade-end connecting member is connected to the blade-end outer bushing by bolts.

6. The pitch change mechanism of the helicopter hub according to claim 1, characterized in that, The inner tension-torsion bar girder and the outer tension-torsion bar girder are composed of multiple strip-shaped structures with both ends turned outwards, and rubber is filled between each strip-shaped structure.

7. The variable pitch mechanism of the helicopter hub according to claim 1, characterized in that, The widths of the strip-shaped structures of the inner tension-torsion bar girder and the outer tension-torsion bar girder are the same and evenly distributed.

8. The pitch change mechanism of the helicopter hub according to claim 1, characterized in that, The maximum size of the blade end of the inner tension-torsion bar girder and the outer tension-torsion bar girder is smaller than the inner diameter of the elastic bearing.

9. An assembly method for a pitch change mechanism of a helicopter hub according to any one of claims 1-8, characterized in that, Comprising: Step 1: Cure the strip-shaped structures of the inner tension-torsion bar girder and the outer tension-torsion bar girder through a compression molding process; Step 2: Place each strip-shaped structure into the card slots of the blade-end inner bushing and the hub-end inner bushing, and into the card slots of the blade-end outer bushing and the hub-end outer bushing respectively; Step 3: Vulcanize and fill rubber between each strip-shaped structure; Step 4: Connect the blade-end inner bushing and the hub-end inner bushing to the blade-end outer side cover plate and the hub-end outer side cover plate respectively; Step 5: Assemble and connect the blade-end outer bushing and the hub-end outer bushing to the blade-end inner bushing and the hub-end inner bushing using bolts respectively; Step 6: Pass the structure obtained in Step 5 through the elastic bearing and connect the elastic bearing to the hub-end outer bushing 8, and connect the blade-end connecting member to the blade-end outer bushing.

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