A processing method of a steering wheel structure in a ducted tail rotor

Abstract

The application discloses a processing method of a control disc structure in a ducted tail rotor, and comprises the following steps: S1, material selection: selecting an aluminum alloy sheet metal part with a thickness of 2 mm; S2, stamping forming: performing multiple hot stamping on the aluminum alloy sheet metal part, and finally obtaining a disc-shaped structure; S3, wire cutting: placing the disc-shaped structure in step S2 on a cutting bed, and processing multiple ear pieces with an inclined angle circular arc streamline structure which are same in number with the number of blades by wire cutting, wherein the connection between the ear pieces and the disc body is smooth connection, the smooth curved surface transition connection is arranged between the two adjacent ear pieces, the included angle alpha between the ear piece and the blade axis is 6 degrees, and the control disc initial product is obtained after the cutting; and S4, grinding and filing: manually filing the cross section of the control disc initial product, the filing direction is same with the wire cutting direction, and the roughness precision of the cross section after the filing reaches 0.4. The control disc processed by the method has high strength, good fatigue resistance and long service life.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ducted tail rotor structure processing, in particular to a processing method of a control disc structure in a ducted tail rotor. BACKGROUND

[0002] The ducted tail rotor of a helicopter is used to provide lateral tension to balance the reaction torque of the main rotor, and the control assembly thereof is mainly converted from linear motion to torsional motion of the rotor blade to realize the variable pitch of the rotor blade. The control assembly of a certain type of tail rotor is designed with an ear piece, the design angle of which is consistent with the inclination angle of the variable pitch pin of the rotor blade to ensure that the ear piece control hole is perpendicular to the variable pitch pin, and the linear motion of the control assembly drives the torsion of the variable pitch pin of the rotor blade, thereby realizing the variable pitch of the rotor blade. The control assembly is an aluminum alloy sheet metal stamping structure mainly subjected to variable pitch force and its own centrifugal force.

[0003] At present, the control disc processed by the traditional processing method has low strength and poor fatigue resistance, which greatly reduces the service life of the control disc.

[0004] Therefore, how to provide a processing method of a control disc structure in a ducted tail rotor, which has high strength, good fatigue resistance and long service life, is a problem that those skilled in the art need to solve. SUMMARY

[0005] Therefore, the present application provides a processing method of a control disc structure in a ducted tail rotor, which has high strength, good fatigue resistance and long service life.

[0006] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] A processing method of a control disc structure in a ducted tail rotor, comprising the following processing steps:

[0008] Step S1: material selection: selecting an aluminum alloy sheet metal part with a thickness of 2-3 mm;

[0009] Step S2: stamping forming: the aluminum alloy sheet metal part in step S1 is subjected to multiple hot stamping to finally obtain a disc structure;

[0010] Step S3: wire cutting: placing the disc structure in step S2 on a cutting bed, and processing a plurality of ear pieces with an inclined circular arc streamline structure in the same number as the number of rotor blades by wire cutting, wherein the connection between the ear piece and the disc body is smooth connection, and the connection between the adjacent two ear pieces is smooth curved surface transition connection, the included angle a between the ear piece and the rotor blade axis is 6°, and the control disc initial product is obtained after cutting;

[0011] ​Step S4: grinding file finishing: manually file finishing the cross section of the manipulator disc rough product, the file finishing direction is the same as the wire cutting direction, and the roughness precision of the cross section after the file finishing reaches 0.4.

[0012] Compared with the prior art, the machining method of the manipulator disc structure in the ducted tail rotor provided by the present application considers the uneven local thickness caused by the stamping process of the sheet metal stamping part, and the overall thickness of the aluminum alloy sheet metal stamping part is designed to be 3.4 mm through strength calculation and analysis. In order to eliminate the fatigue source of the main stress part as much as possible, the roughness of the stress part, especially the roughness of the stress section of the plate, is designed to be 0.4, so that the influence of the surface finish on the fatigue performance can be reduced. The wire cutting is used for the ear piece forming of the thin-walled stamping structure, and in order to ensure the consistency of the main stress direction of the adjacent ear piece transition area and eliminate the fatigue stress, the wire cutting direction is consistent with the file finishing direction. In addition, the inclined angle arc streamline design is used between the ear pieces and the ear piece, and the smooth connection is used between the ear piece and the disc body. The design focuses on details, eliminates the unsmooth phenomenon of the large stress transition area between the two ear pieces and the ear piece and the body, ensures the smooth transition requirement of the transition area, and eliminates the stress concentration caused by the unsmoothness as much as possible. At the same time, in order to ensure the strength of the overall sheet metal stamping part and improve the fatigue performance, considering that the manipulator disc is provided with ear pieces and is an aluminum alloy thin-walled structure part, the structure is complex, and the machining is difficult. Therefore, the manipulator disc is processed by using the sheet metal multiple stamping process. Therefore, the present application considers the strength reduction caused by the local thickness reduction of the aluminum alloy sheet metal stamping part, enhances the overall strength, considers the influence of the surface finish of the aluminum alloy sheet metal stamping structure on the fatigue performance, and eliminates the fatigue source and reduces the stress concentration from the manufacturing details as much as possible, so as to improve the fatigue performance of the component and finally improve the service life of the part. Therefore, the manipulator disc processed by the present application has high strength, good fatigue resistance and long service life.

[0013] Further, the wire cutting starting point in step S3 is from the highest point of the ear piece.

[0014] The beneficial effects produced by the above technical scheme are that in order to ensure the stress concentration caused by the cutting starting point, the cutting starting point should avoid the two ear piece transition areas of the main stress part, so that the starting point is at the top of the ear piece.

[0015] Further, in step S3, an ear piece hole is wire cut on the ear piece, and a wear-resistant bushing for a blade variable pitch pin is fixed in the ear piece hole.

[0016] Further, the wear-resistant bushing is bonded and fixed with the ear piece hole.

[0017] The beneficial effect produced by the above technical solution is that the wear-resistant bushing is arranged to make the paddle pitch pin rotate flexibly and reduce wear.

[0018] Further, in the step S2, the working surface of the stamping die is cleaned and lubricated before each stamping.

[0019] The beneficial effect produced by the above technical solution is that the material and the stamping die are prevented from adhering to each other during stamping, thereby affecting the quality of the to-be-stamped part. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings in the following description only represent some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of the provided drawings.

[0021] Figure 1 The drawing is a process flow diagram of a machining method of a control disc structure in a ducted tail rotor.

[0022] Figure 2 The drawing is a structural schematic diagram of the control disc provided by the present application.

[0023] Figure 3 The drawing is a top view structural schematic diagram of the control disc.

[0024] Figure 4 The drawing is a structural schematic diagram of the ear piece wire cutting and filing direction consistency. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments only represent some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort fall within the scope of protection of the present application.

[0026] The embodiment of the present application discloses a machining method of a control disc structure in a ducted tail rotor, comprising the following machining steps:

[0027] Step S1: material selection: selecting an aluminum alloy sheet metal part with a thickness of 2-3 mm;

[0028] ​Step S2: punch forming: the aluminum alloy sheet metal part in step S1 is subjected to multiple hot stamping, and finally a disc-shaped structure 1 is obtained; specifically, the steering disc is a disc-shaped aluminum alloy structure, thin-walled, and is formed by multiple stamping using a mold, and heat treatment is performed before each stamping to make the material in a soft state, i.e. to increase the ductility of the material, and after stretching, heat treatment is performed again, and this is repeated 4 times, and the designed structure can be obtained;

[0029] Step S3: wire cutting: the disc-shaped structure 1 in step S2 is placed on a cutting bed, and multiple ear pieces 2 in the form of inclined circular arc streamline structures are machined by wire cutting, the number of which is the same as the number of blades, wherein the connection between the ear piece 2 and the disc body is smooth connection, and the connection between the adjacent two ear pieces 2 is smooth curved surface transition connection, the included angle α between the ear piece 2 and the blade axis is 6°, and the steering disc is obtained after cutting;

[0030] Step S4: grinding and filing: the cross section of the steering disc is filed by hand, and the filing direction is the same as the wire cutting direction, i.e. the filing direction is processed according to the wire cutting feeding direction, and the roughness precision of the cross section after filing reaches 0.4.

[0031] The wire cutting starting point in step S3 is the highest point 201 of the ear piece 2.

[0032] In step S3, an ear piece hole 202 is wire cut on the ear piece 2, and a wear-resistant bushing 3 for the blade variable moment pin is inserted into the ear piece hole 202, the wear-resistant bushing 3 is made of tungsten carbide, and the inner surface of the bushing has a lubricating layer.

[0033] The wear-resistant bushing 3 is bonded and fixed with the ear piece hole 202.

[0034] In step S2, the working surface of the stamping die is cleaned before each stamping, and the lubrication is strengthened.

[0035] In the method, the uneven local thickness caused by stamping process of the sheet metal stamping part is considered, the overall thickness of the aluminum alloy sheet metal stamping part is designed to be 3.4mm through strength calculation analysis; in order to eliminate the fatigue source of the main stress position as much as possible, the roughness of the stress position is improved, especially the roughness of the stress section of the plate, the roughness is designed to be 0.4, so that the influence of surface finish on fatigue performance can be reduced; the wire cutting is adopted for the ear forming of the thin-walled stamping structure, so that the ear processing is simple, in order to ensure the consistency of the main stress direction of the adjacent ear transition area and eliminate the fatigue stress, the wire cutting direction is consistent with the file direction; and the inclined angle arc streamline design is adopted between the ears and the shape of the ears, the smooth connection is adopted between the ears and the disc, the detail design is paid attention to, the unsmooth phenomenon of the two ears and the large stress transition area of the ear and the body is eliminated, the smooth transition requirement of the transition area is ensured, and the stress concentration caused by the unsmooth is eliminated as much as possible; meanwhile, in order to ensure the strength of the whole sheet metal stamping part and improve the fatigue performance, considering that the control disc is provided with ears and is an aluminum alloy thin-walled structure part, the design structure is complex, and the machining difficulty is too large, the sheet metal multiple stamping process is selected for the control disc. Therefore, the control disc processed by the present application has high strength, good fatigue resistance and long service life.

[0036] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. For the device disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple, and the related parts can be referred to the method part.

[0037] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to the embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for processing a control disc structure in a ducted tail rotor, characterized in that: The processing steps include: Step S1: Material selection: Select thickness mm aluminum alloy sheet metal parts; Step S2: stamping: the aluminum alloy sheet metal part in step S1 is subjected to multiple hot stamping processes to obtain a disk-shaped structure (1); Step S3: Wire cutting: placing the disc-shaped structure (1) in step S2 on a cutting bed, and processing a plurality of lugs (2) with an oblique arc streamline structure, which are the same number as the blades, by wire cutting, wherein the connection between the lugs (2) and the disc body is smooth, and the connection between two adjacent lugs (2) is a smooth curved surface transition, and the angle α between the lugs (2) and the blade axis is 6°. After the cutting is completed, the initial product of the control disc is obtained; Step S4: Grinding and filing: Manually file the cross section of the initial product of the control plate. The filing direction is the same as the wire cutting direction. The cross section roughness accuracy after filing reaches 0.4; The starting point of the line cutting in step S3 is the highest point (201) of the ear piece (2).

2. The method for processing a control disc structure in a ducted tail rotor according to claim 1, characterized in that: In step S3, an ear hole (202) is cut on the ear (2), and a wear-resistant bushing (3) for the blade torque converter pin to pass through is passed through the ear hole (202).

3. The method for processing a control disc structure in a ducted tail rotor according to claim 2, characterized in that: The wear-resistant bushing (3) is bonded and fixed to the ear hole (202).

4. The method for processing a control disc structure in a ducted tail rotor according to claim 1, characterized in that: In step S2, the working surface of the stamping die is cleaned and lubricated before each stamping.

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