Helicopter tail rotor flexible beam flapping fatigue test piece forming mold and method

Abstract

The invention relates to a helicopter tail rotor flexible beam flapping fatigue test piece forming mold and method, and the mold comprises a mold body which is used for forming connection reinforcing parts at the two ends of a flexible beam flapping test piece, the bottom of the mold body is connected with a supporting part, and the supporting part is horizontally provided with a first connection hole in a penetrating manner; the length of the distance piece is determined according to the length of a waving deformation area of the flexible beam waving test piece; the top of the positioning part is connected with a central metal lining which is adhered to the central area of the flexible beam waving test piece and has a non-deformation characteristic, the bottom of the positioning part is provided with a second connecting hole opposite to the first connecting hole, and the distance piece penetrates through the first connecting hole and the second connecting hole respectively and is detachably connected with the first connecting hole; or the first connecting hole and the second connecting hole are detachably connected; and the mold body, the distance fixing piece and the positioning part form a simply supported beam rigid system relative to the flexible beam waving test piece, so that the axial lead of the flexible beam waving test piece is always in the same straight line.

Description

Technical Field

[0001] The invention relates to the field of aerospace technology, and more particularly to a forming die and method for a helicopter tail rotor flexible beam flapping fatigue test piece. Background Art

[0002] The tail rotor system of some helicopters realizes the flapping, shimmying and pitch-changing motion of the tail rotor blades through the elastic deformation of the carbon fiber flexible beam. The flexible beam is the core key component of the tail rotor, which is mainly divided into: the root connection area (including the centrifugal force diversion opening), the torsional deformation area, the flapping deformation area, the transition area connected to the tail rotor blade, and the tail rotor blade beam area.

[0003] The flexible beam swing fatigue test is an important means to ensure its reliability and durability. The flexible beam swing fatigue test piece is a shortened piece of the flexible beam body, retaining the swing deformation zone, with positions at both ends dedicated to laying connection reinforcement materials. The reinforcement material is a composite fiber cloth, which is heated and cured.

[0004] The original similar fatigue test pieces were formed by vacuum bag wrapping and vacuum extraction, and then mechanically processed and manually polished. This was inefficient, labor-intensive, and had unstable quality and scattered data.

[0005] Therefore, according to the above situation, in order to ensure the geometric accuracy and quality consistency of the flapping fatigue test piece, how to provide a molding mold and method for the flapping fatigue test piece of the tail rotor flexible beam of the helicopter is a problem that technical personnel in this field urgently need to solve. Summary of the invention

[0006] The present invention aims to solve one of the above-mentioned technical problems in the prior art at least to a certain extent.

[0007] Therefore, an object of the present invention is to provide a mold to ensure the geometric accuracy and quality consistency of the swing fatigue test piece.

[0008] Another object of the present invention is to provide a molding method.

[0009] The technical solution of the present invention is a forming die for a helicopter tail rotor flexible beam flapping fatigue test piece, comprising:

[0010] The mold body is used to form the connection reinforcement parts at both ends of the flexible beam swinging test piece, and the bottom of the mold body is connected to a support part, and the support part is horizontally penetrated by a first connection hole;

[0011] The distance piece, the length of which is determined according to the length of the swing deformation zone of the flexible beam swing test piece;

[0012] A positioning part, the top of which is connected to a central metal bushing with non-deformation characteristics bonded to the central area of ​​the flexible beam swinging test piece, serving as a middle positioning reference, and the bottom of which has a second connection hole opposite to the first connection hole, the distance piece passes through the first connection hole and the second connection hole respectively, and is detachably connected to the first connection hole, or is detachably connected to the first connection hole and the second connection hole;

[0013] The mold body, the distance piece and the positioning part form a simply supported beam rigid system relative to the flexible beam swinging test piece, so that the axis of the flexible beam swinging test piece is always in the same straight line.

[0014] According to the molding die of the present invention, the support portion and the bottom surface of the positioning portion are on the same horizontal plane, and the axes of the first connecting hole and the second connecting hole are on the same straight line.

[0015] According to the molding die of the present invention, the distance pieces are two horizontally arranged distance rods, and the length of the distance rods is the length of the flexible beam swinging test piece of the test piece, or is half of the length of the flexible beam swinging test piece.

[0016] According to the molding die of the present invention, the positioning portion comprises:

[0017] Two support plates are arranged in parallel and provided with the second connection holes;

[0018] A middle rib plate connected between the two support plates;

[0019] A positioning plate connected to the support plate and the top of the middle rib plate;

[0020] The positioning shaft has a central metal bushing inserted into the central area of ​​the flexible beam, and is connected with the fastener through the connecting structure at the end of the positioning shaft.

[0021] According to the molding die of the present invention, the connection structure is a threaded structure, the fastener is a clamping nut, and a washer is installed between the clamping nut and the central metal bushing in the central area of ​​the flexible beam.

[0022] According to the molding die of the present invention, the die body comprises:

[0023] A lower template is fixed to the top of the support portion;

[0024] Side template 1 and side template 2 are located on both sides of the lower template and are detachably connected to the lower template;

[0025] The upper template is plugged into the plug-in area formed by the side template one and the side template two at the bottom and fixed. The upper template, the lower template, the side template one, the side template two and the back plate form a cavity, and an opening for the end of the flexible beam swinging test piece is left between the upper template and the lower template, and the shape of the opening matches the end of the flexible beam swinging test piece.

[0026] According to the molding mold of the present invention, the structures of the side template one and the side template two are mirror-arranged structures, both of which include an upper plate and a lower plate that are integrally connected, and a first plug-in portion located at the end of the upper plate, and the upper template is provided with a second plug-in portion near the first plug-in portion.

[0027] According to the molding mold of the present invention, the supporting part includes two support plates and a rib plate to form an I-shaped structure, the top surface of the I-shaped structure is fixed to the bottom surface of the lower template, the first connecting hole is arranged on the support plate, and the two ends of the distance piece are connected by locking nuts.

[0028] The forming method of the helicopter tail rotor flexible beam flapping fatigue test piece forming die of the present invention comprises the following steps:

[0029] S1, processing flexible beam swing test piece;

[0030] S2. Lay composite glass tapes and wrap glass cloth at the connection and reinforcement parts at both ends of the flexible beam swinging test piece;

[0031] S3, placing the end of the flexible beam swinging test piece processed in S2 into the area formed by the side template 1, the side template 2 and the lower template, pressurizing and locking the side template 1 and the side template 2, and then plugging the upper template;

[0032] S4, pressurizing and heating the upper template to solidify and form the end connection reinforcement part of the flexible beam swinging test piece;

[0033] S5. After cooling, open the mold and take out the parts;

[0034] S6. After cooling in S5, the end connection reinforcement parts of the flexible beam swinging test piece are reshaped, polished, and cleaned.

[0035] According to the above method of the present invention, the end connection reinforcement part of the flexible beam swinging test piece is formed by first forming a single end with one mold and then forming the other end; or forming both ends simultaneously with two molds.

[0036] It can be seen from the above technical solution that, compared with the prior art, the technical effects of the present invention are:

[0037] 1. The present invention forms the flexible beam swing fatigue test piece through a special mold, avoiding the complex process of traditional vacuum bag wrapping and vacuuming, reducing the workload of later mechanical processing and manual polishing, and improving production efficiency.

[0038] 2. The mold structure is reasonably designed, and the mold body, distance pieces and positioning parts are used to form a simply supported beam rigid system, which ensures that the axis line of the flexible beam swinging test piece is always in the same straight line, ensuring the geometric accuracy and quality consistency of the test piece.

[0039] 3. The various parts of the mold can be detachably connected, which is convenient for adjustment and maintenance. At the same time, the mold body, distance pieces and positioning parts have high matching accuracy, making the operation process simpler.

[0040] 4. Through mold forming, the connection reinforcement part at the end of the flexible beam swinging test piece is more stable, reducing the error and instability caused by manual grinding and improving the overall quality of the product.

[0041] 5. Reduce the labor intensity of workers and improve the working environment.

[0042] 6. The mold forming method makes the product quality more stable and the data is centralized, which is convenient for subsequent quality control and data analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0044] Figure 1 A cross-sectional view of a forming die for a helicopter tail rotor flexible beam flapping fatigue test piece provided by the present invention;

[0045] Figure 2 A three-dimensional diagram of a forming die for a helicopter tail rotor flexible beam flapping fatigue test piece provided by the present invention (the lower template and multiple fasteners are not shown);

[0046] Figure 3 for Figure 1 AA section view;

[0047] Figure 4 A three-dimensional diagram of the mold body is shown (the lower mold plate is not shown);

[0048] Figure 5 This is an exploded view of the mold body;

[0049] Figure 6 A schematic diagram of side template 1 or side template 2 is shown;

[0050] Figure 7 The schematic diagram of the structure of the positioning part is shown. DETAILED DESCRIPTION

[0051] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0052] In the description of the present invention, it is necessary to understand that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship 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 cannot be understood as a limitation on the present invention.

[0053] Since the original similar fatigue test piece products are formed by vacuum bag wrapping and vacuuming, and the later mechanical processing is combined with manual polishing, the efficiency is low, the work intensity is high, the quality is unstable, and the data is scattered. In view of this, the solution provided by the present invention is a helicopter tail rotor flexible beam waving fatigue test piece forming mold, see the attached Figure 1-7 ,include:

[0054] The mold body 10 is used to form the connection reinforcement parts at both ends of the flexible beam swinging test piece W, and the bottom of the mold body 10 is connected to a support part 40, and the support part 40 is horizontally penetrated by a first connection hole 41;

[0055] The distance piece 20, the length of which is determined according to the length of the swing deformation zone of the flexible beam swing test piece W;

[0056] The positioning part 30 has a central metal bushing with non-deformation characteristics bonded to the central area of ​​the flexible beam swinging test piece W at the top, which serves as a central positioning reference, and a second connection hole 31 at the bottom thereof which is opposite to the first connection hole 41. The distance piece 20 passes through the first connection hole 41 and the second connection hole 31 respectively, and is detachably connected to the first connection hole 41, or is detachably connected to the first connection hole 41 and the second connection hole 31;

[0057] The mold body 10 , the distance piece 20 and the positioning portion 30 form a simply supported beam rigid system relative to the flexible beam swinging test piece W, so that the axis L of the flexible beam swinging test piece W is always in the same straight line.

[0058] In the above embodiment, the present invention forms the flexible beam swinging fatigue test piece through a special mold, avoiding the complicated process of traditional vacuum bag wrapping and vacuum forming, reducing the workload of later mechanical processing and manual polishing, and improving production efficiency. The mold body, distance pieces and positioning parts are used to form a simply supported beam rigid system, ensuring that the axis of the flexible beam swinging test piece is always in the same straight line, ensuring the geometric accuracy and quality consistency of the test piece.

[0059] In the above embodiments, see the attached Figure 2 The support portion 40 and the bottom surface of the positioning portion 30 are on the same horizontal plane, and the axes of the first connection hole 41 and the second connection hole 31 are on the same straight line. Ensure that the axis L of the flexible beam swinging test piece W is always on the same straight line.

[0060] In one embodiment of the present invention, the distance member 20 is two horizontally arranged distance rods.

[0061] In the embodiments of the present invention, see the attached Figure 7 , the positioning portion 30 includes:

[0062] Two support plates 32 are arranged in parallel and provided with the second connection holes 31. The length of the distance rod determines whether the second connection holes 31 are provided on both support plates 32 or on one support plate 32.

[0063] A middle rib plate 34 is connected between the two support plates 32 to strengthen the rigidity of the two support plates 32;

[0064] A positioning plate 33 connected to the support plate 32 and the top of the middle rib plate 34;

[0065] The positioning shaft 35 is inserted into the central metal bushing in the central area of ​​the flexible beam, and is connected with the fastener 37 through the connection structure at the end of the positioning shaft 35. The connection structure can be a threaded structure, and the fastener 37 can be a compression nut. A washer 36 is installed between the compression nut and the central metal bushing in the central area of ​​the flexible beam. Figure 1 .

[0066] In the embodiments of the present invention, see the attached Figure 4 and 5 , the mold body 10 includes:

[0067] The lower template 14 is fixed to the top of the support portion 40;

[0068] Side template 1 12 and side template 2 13 are located on both sides of the lower template 14 and are detachably connected to the lower template 14, and form a restricted area for the end portion W of the flexible beam swinging test piece to be initially placed in the mold cavity;

[0069] The upper template 11 is inserted and fixed at the bottom in the insertion area formed by the side template 12 and the side template 2 13. The upper template 11, the lower template 14, the side template 12, the side template 2 13 and the back plate 15 form a cavity inside, and an opening for the end W of the flexible beam swinging test piece is left between the upper template 11 and the lower template 14, and the shape of the opening matches the end W of the flexible beam swinging test piece.

[0070] In this embodiment, the various parts of the mold can be detachably connected, which is convenient for adjustment and maintenance. At the same time, the mold body, the distance piece and the positioning part have high matching accuracy, making the operation process simpler. Through mold forming, the connection reinforcement part at the end of the flexible beam swinging test piece is more stable, reducing the error and instability caused by manual grinding, and improving the overall quality of the product. It reduces the labor intensity of workers and improves the working environment.

[0071] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0072] See attached Figure 6 The structures of the side template 12 and the side template 2 13 are mirror-arranged structures, both of which include an upper plate 121 and a lower plate 122 that are integrally connected, and a first plug-in portion 123 located at the end of the upper plate 121, and the upper template 11 is provided with a second plug-in portion 111 near the first plug-in portion 123.

[0073] The first plug-in portion 123 and the second plug-in portion 111 are mutually matched structures, which can be a matching form of multiple contact planes or multiple inclined surfaces, to ensure that after plugging, the upper template and the side template 1 12 and the side template 2 13 fit tightly together, have a certain fixing effect and no interference.

[0074] See attached Figure 4 and 5 The support portion 40 includes two support plates 42 and a rib plate 43 to form an I-shaped structure. The top surface of the I-shaped structure is fixed to the bottom surface of the lower template 14. The first connecting hole 41 is provided on the support plate 42. Both ends of the distance piece 20 are connected by locking nuts 21.

[0075] In the embodiment of the present invention, the two support plates 42, the rib plate 43 and the lower template 14 can be welded as a whole, and the two support plates 32, the middle rib plate 34 and the positioning plate 33 can be welded as a whole.

[0076] The mold body is made of hot-done mold steel, the distance rod is made of GCr15 cold-drawn round steel with high tensile strength, yield strength and high contact fatigue strength, the positioning part is made of high-quality carbon structural steel, and the welding connection part of the mold is made of low-carbon easy-to-weld steel. The rest are standard fasteners.

[0077] In the present invention, unless otherwise clearly stipulated and limited, the terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; it can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0078] The present invention also provides a forming method of the helicopter tail rotor flexible beam flapping fatigue test piece forming die, comprising the following steps:

[0079] S1, processing flexible beam swing test piece;

[0080] S2. Lay composite glass tapes and wrap glass cloth at the connection and reinforcement parts at both ends of the flexible beam swinging test piece;

[0081] S3, placing the end of the flexible beam swinging test piece processed in S2 into the area formed by the side template 1, the side template 2 and the lower template, pressurizing and locking the side template 1 and the side template 2, and then plugging the upper template;

[0082] S4. Pressurize and heat the upper template to solidify and form the end connection reinforcement part of the flexible beam swinging test piece; the pressurization pressure is determined according to actual needs and can be 10t;

[0083] S5. After cooling, open the mold and take out the parts; natural cooling can be adopted;

[0084] S6. After cooling in S5, the end connection reinforcement parts of the flexible beam swinging test piece are reshaped, polished, and cleaned.

[0085] The end connection reinforcement part of the flexible beam swing test piece is formed by first forming one end of a mold and then forming the other end. The length of the distance rod corresponding to this method is half the length W of the flexible beam swing test piece of the test piece; or two molds are used to form both ends at the same time, and the corresponding distance rod is the length W of the flexible beam swing test piece. The attached drawings of the present invention illustrate the former.

[0086] The method of the present invention makes product quality more stable and data centralized, which is convenient for subsequent quality control and data analysis.

[0087] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0088] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A forming die for a helicopter tail rotor flexible beam waving fatigue test piece, characterized in that: include: The mold body (10) is used to form the connection reinforcement parts at both ends of the flexible beam swinging test piece (W), and the bottom of the mold body is connected to a support part (40), and the support part (40) is horizontally penetrated by a first connection hole (41); A distance piece (20), the length of which is determined according to the length of the swing deformation zone of the flexible beam swing test piece (W); A positioning portion (30), the top of which is connected to a central metal bushing with non-deformation characteristics and bonded to the central area of ​​the flexible beam swinging test piece (W), serving as a central positioning reference, and the bottom of which is provided with a second connection hole (31) opposite to the first connection hole (41); the distance piece (20) passes through the first connection hole (41) and the second connection hole (31) respectively, and is detachably connected to the first connection hole (41), or is detachably connected to the first connection hole (41) and the second connection hole (31); The mold body (10), the distance piece (20) and the positioning portion (30) form a simply supported beam rigid system relative to the flexible beam swinging test piece (W), so that the axis (L) of the flexible beam swinging test piece (W) is always in the same straight line.

2. The helicopter tail rotor flexible beam flapping fatigue test piece forming die according to claim 1, characterized in that: The support portion (40) and the bottom surface of the positioning portion (30) are located on the same horizontal plane, and the axes of the first connecting hole (41) and the second connecting hole (31) are located on the same straight line.

3. The helicopter tail rotor flexible beam flapping fatigue test piece forming die according to claim 1, characterized in that: The distance pieces (20) are two horizontally arranged distance rods, and the length of the distance rods is the length of the flexible beam swinging test piece (W) of the test piece, or is half the length of the flexible beam swinging test piece (W).

4. The helicopter tail rotor flexible beam flapping fatigue test piece forming die according to claim 1, characterized in that: The positioning portion (30) comprises: Two support plates (32) are arranged in parallel and are provided with the second connection holes (31); A middle rib plate (34) connected between the two support plates (32); A positioning plate (33) connected to the support plate (32) and the top of the middle rib plate (34); A positioning shaft (35) is inserted with a central metal bushing in the central area of ​​the flexible beam, and is connected to a fastener (37) through a connecting structure at the end of the positioning shaft (35).

5. The helicopter tail rotor flexible beam flapping fatigue test piece forming die according to claim 4, characterized in that: The connection structure is a threaded structure, the fastener (37) is a compression nut, and a washer (36) is installed between the compression nut and the central metal bushing in the central area of ​​the flexible beam.

6. The helicopter tail rotor flexible beam flapping fatigue test piece forming die according to claim 1, characterized in that: The mold body (10) comprises: A lower template (14) is fixed to the top of the support portion (40); Side template one (12) and side template two (13) are located on both sides of the lower template (14) and are detachably connected to the lower template (14); The upper template (11) is plugged and fixed at its bottom in a plug-in area formed by the side template one (12) and the side template two (13); the upper template (11), the lower template (14), the side template one (12), the side template two (13) and the back plate (15) form a cavity inside; and an opening for the end of the flexible beam swinging test piece (W) is left between the upper template (11) and the lower template (14); the shape of the opening matches the end of the flexible beam swinging test piece (W).

7. The helicopter tail rotor flexible beam flapping fatigue test piece forming die according to claim 6, characterized in that: The structures of the side template 1 (12) and the side template 2 (13) are mirror-image structures, both of which include an upper plate (121) and a lower plate (122) that are integrally connected, and a first plug-in portion (123) located at the end of the upper plate (121), and the upper template (11) is provided with a second plug-in portion (111) near the first plug-in portion (123).

8. The helicopter tail rotor flexible beam flapping fatigue test piece forming die according to claim 6, characterized in that: The support portion (40) comprises two support plates (42) and a rib plate (43) forming an I-shaped structure, the top surface of the I-shaped structure is fixed to the bottom surface of the lower template (14), the first connecting hole (41) is arranged on the support plate (42), and the two ends of the distance piece (20) are connected by a locking nut (21).

9. The method for forming a helicopter tail rotor flexible beam flapping fatigue test piece forming die according to any one of claims 6 to 8, characterized in that: The following steps are involved: S1, processing flexible beam swing test piece; S2. Lay composite glass tapes and wrap glass cloth at the connection and reinforcement parts at both ends of the flexible beam swinging test piece; S3, placing the end of the flexible beam swinging test piece processed in S2 into the area formed by the side template 1, the side template 2 and the lower template, pressurizing and locking the side template 1 and the side template 2, and then plugging the upper template; S4, pressurizing and heating the upper template to solidify and form the end connection reinforcement part of the flexible beam swinging test piece; S5. After cooling, open the mold and take out the parts; S6. After cooling in S5, the end connection reinforcement parts of the flexible beam swinging test piece are reshaped, polished, and cleaned.

10. The method according to claim 9, characterized in that The end connection reinforcement part of the flexible beam swinging test piece is formed by first forming a single end with one mold and then forming the other end; or forming both ends at the same time with two molds.

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