Fan blade assembling structure and assembling method

Abstract

The invention relates to a fan blade assembling structure and method. The fan blade assembly structure comprises a fan disc provided with a mounting groove; the blade roots of the fan blades are mounted in the mounting grooves; the blade base plate is arranged in the mounting groove, the blade base plate is of a layered structure and comprises a first hard wear-resisting layer and a second hard wear-resisting layer, an expansion layer is arranged between the first hard wear-resisting layer and the second hard wear-resisting layer, the first hard wear-resisting layer is attached to the bottom face of the blade root, and the second hard wear-resisting layer is attached to the fan disc; the first hard wear-resistant layer, the second hard wear-resistant layer and the expansion layer are connected and fixed through bolts. According to the fan blade assembling structure and method, assembling is convenient, the overall structure is more stable, and the service life is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of aero-engine assembly, and particularly to an assembly structure and an assembly method for fan blades. Background Art

[0002] Fan blades are one of the important components of turbofan engines. Their main function is to initially compress the air entering the engine. After that, a part of the gas enters the core duct for further compression and is mixed with fuel for combustion, while another part of the gas is directly discharged at high speed through the bypass duct. The thrust generated by the fan generally accounts for more than half of the total thrust of the turbofan aero-engine. The fan blades are assembled into the dovetail grooves of the fan disk through dovetails. The gaps in the dovetail grooves need to be filled with pad-like parts to adjust the fan blade clearance, and can play certain roles in shock absorption, anti-wear, cooling to prevent high temperature, reducing fan noise, etc.

[0003] To enable the fan blade pads to achieve functions such as clearance adjustment, shock absorption, and anti-wear, generally, there is a certain dimensional interference in the design of the fan blade pads to ensure that the fan blades and the fan disk are in a tight fit state under static conditions. However, this design also makes the assembly difficult, and some structures need to be designed to achieve the positioning effect, such as using bolts and nuts to connect with the disk and the front and rear baffles. In addition, the shock absorption performance and wear resistance of the pads also need to be improved to extend the service life of the pads, reduce the replacement cycle and failure rate, and reduce blade vibration, engine noise, etc.

[0004] Chinese Patent Application for Invention CN201810059104.8, with an application date of January 22, 2018 and a publication date of June 29, 2018, discloses a vehicle rubber pad with expansion shock absorption. The vehicle rubber pad includes a bottom plate. Using polytetrafluoroethylene to make the bottom plate ensures the stability of the rubber pad. The buffer layer made of natural latex has high elasticity, and the rubber film has excellent flexural fatigue resistance, seismic resistance, and creep resistance, and can effectively absorb energy. The sealing ring made of butyl rubber, when vibrating, generates heat through the mutual friction of metal particles, and then heats the hydrogen in the hydrogen chamber through the sealing ring, thereby achieving the expansion effect, and can effectively inhibit the problem that the rubber pad of the material cannot bear due to excessive vibration force. The telescopic mechanism, while increasing the buffer effect, also increases the friction coefficient between the engine and the rubber pad through the telescopic block. This patent application has a layered structure and is mainly used for vehicle shock absorption, but is not applicable to the assembly of fan blades. Summary of the Invention

[0005] Aiming at the above problems of the prior art, the present invention proposes an assembly structure and an assembly method for fan blades, which are convenient for assembly, the overall structure is more stable, and the service life is extended.

[0006] Specifically, the present invention provides a fan blade assembly structure applicable to an aeroengine. The fan blade assembly structure includes:

[0007] A fan disk provided with an installation groove;

[0008] A fan blade, the blade root of which is installed in the installation groove;

[0009] A blade backing plate disposed in the installation groove. The blade backing plate is a layered structure, including a first hard wear-resistant layer and a second hard wear-resistant layer. An expansion layer is provided between the first and second hard wear-resistant layers. The first hard wear-resistant layer abuts against the bottom surface of the blade root, and the second hard wear-resistant layer abuts against the fan disk. The first and second hard wear-resistant layers and the expansion layer are fixedly connected by bolts.

[0010] According to an embodiment of the present invention, the first and second hard wear-resistant layers are made of a resin matrix composite material or are the same as the material of the fan blade.

[0011] According to an embodiment of the present invention, weight-reducing grooves are formed in the first and second hard wear-resistant layers.

[0012] According to an embodiment of the present invention, the expansion layer is made of an elastic material.

[0013] According to an embodiment of the present invention, the expansion coefficient of the expansion layer is greater than 5×10 -4 / °C.

[0014] According to an embodiment of the present invention, both ends of the bolt are embedded in the surface of the blade backing plate.

[0015] The present invention also provides a fan blade assembly method applicable to the aforementioned fan blade assembly structure. The fan blade assembly method includes the steps of:

[0016] S1, cryogenically freezing the blade backing plate;

[0017] S2, placing the cryogenically frozen blade backing plate into the installation groove of the fan disk, and inserting the blade root of the fan blade into the installation groove;

[0018] S3, allowing the blade backing plate to return to the room temperature of the assembly room, so that the blade backing plate is in interference fit with the installation groove.

[0019] The fan blade assembly structure and the assembly method provided by the present invention adopt a three-layer combined structure for the blade backing plate, with the expansion layer disposed between two wear-resistant layers, which is suitable for reducing the assembly difficulty. Cryogenic freezing assembly is adopted, making the assembly convenient, the overall structure more stable, and the service life prolonged.

[0020] It should be understood that the above general description and the following detailed description of the present invention are both exemplary and explanatory, and are intended to provide further explanation of the present invention described. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings are provided to further understand the present invention, and they are incorporated and constitute a part of this application. The drawings illustrate embodiments of the present invention and, together with this specification, serve to explain the principles of the present invention.

[0022] In the drawings:

[0023] Figure 1 FIG. shows a schematic structural diagram of a fan blade assembly structure according to an embodiment of the present invention.

[0024] Figure 2 FIG. shows a schematic structural diagram of a blade backing plate according to an embodiment of the present invention.

[0025] Figure 3 FIG. shows a flowchart of a fan blade assembly method according to an embodiment of the present invention.

[0026] Among them, the above-mentioned drawings include the following reference numerals:

[0027] Assembly structure 100

[0028] Fan disk 101

[0029] Fan blade 102

[0030] Blade backing plate 103

[0031] First hard wear-resistant layer 104

[0032] Second hard wear-resistant layer 105

[0033] Expansion layer 106

[0034] Bolt 107

[0035] Weight reduction groove 108

[0036] Blade root 109

[0037] Mounting groove 110 DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other.

[0039] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way restricts the present application and its application or use. 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.

[0040] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments of the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0041] Unless otherwise specifically stated, the relative arrangements, numerical expressions, and numerical values of the components and steps set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for the sake of convenience of description, the dimensions of the various parts shown in the drawings are not drawn in actual proportional relationships. Technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the said technologies, methods, and devices should be regarded as part of the authorized specification. In all the examples shown and discussed here, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numerals and letters denote like items in the following drawings, and thus, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0042] In the description of the present application, it should be understood that the orientation or positional relationships indicated by orientation words such as "front, rear, upper, lower, left, right", "lateral, vertical, perpendicular, horizontal", and "top, bottom" are generally based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description. Without contrary description, these orientation words do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and thus cannot be construed as limiting the scope of protection of the present application; the orientation words "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0043] For ease of description, spatial relative terms, such as "above", "over", "on the upper surface", "upper", etc., may be used herein to describe the spatial positional relationship of one device or feature to other devices or features as shown in the figures. It should be understood that the spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is inverted, a device described as "above" or "over" other devices or structures will then be positioned "below" or "under" the other devices or structures. Thus, the exemplary term "above" can include both orientations of "above" and "below". The device may also be positioned in other different ways, rotated 90 degrees or in other orientations, and the corresponding interpretations of the spatial relative descriptions used herein will be made accordingly.

[0044] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of differentiating the corresponding components. Without further statement, the above terms have no special meaning, and thus should not be construed as limiting the scope of protection of this application. In addition, although the terms used in this application are selected from well-known and commonly used terms, some of the terms mentioned in the specification of this application may be selected by the applicant according to his or her judgment, and their detailed meanings are described in the relevant parts of this description. In addition, it is required to understand this application not only through the actual terms used, but also through the meaning implied by each term.

[0045] Figure 1 The structural schematic diagram of the fan blade assembly structure according to an embodiment of the present invention is shown. Figure 2 The structural schematic diagram of the blade backing plate according to an embodiment of the present invention is shown. As shown in the figure, the present invention provides a fan blade assembly structure 100 suitable for an aeroengine. The fan blade assembly structure 100 mainly includes a fan disk 101, fan blades 102, and a blade backing plate 103.

[0046] Among them, an installation groove 110 is provided on the fan disk 101.

[0047] The blade root 109 of the fan blade 102 is installed in the installation groove 110.

[0048] The blade backing plate 103 is disposed in the installation groove 110. Refer to Figure 2, the blade backing plate 103 has a layered structure and includes a first hard wear-resistant layer 104 and a second hard wear-resistant layer 105. An expansion layer 106 is provided between the first and second hard wear-resistant layers 105. The first hard wear-resistant layer 104 is attached to the bottom surface of the blade root 109, and the second hard wear-resistant layer 105 is attached to the fan disk 101. The first and second hard wear-resistant layers 104, 105 and the expansion layer 106 are connected and fixed by bolts 107 to enhance the structural stability. Among them, the first and second hard wear-resistant layers 104, 105 have a wear-resistant function and maintain cooperation with the bottom surface of the blade root 109 and the fan disk 101. The volume of the expansion layer 106 changes with temperature and is suitable for the low-temperature freezing assembly method, which will be described in detail later.

[0049] Preferably, the first and second hard wear-resistant layers 104, 105 are made of resin-based composite materials or the same material as that of the fan blade 102. This structure is beneficial to improving the wear resistance of the contact surfaces between the first and second hard wear-resistant layers 104, 105 and adjacent components and extending the service life of the overall structure.

[0050] Preferably, weight-reducing grooves 108 are provided on the first and second hard wear-resistant layers 104, 105 to reduce the weight of the overall structure.

[0051] Preferably, the expansion layer 106 is made of an elastic material. A material with certain elasticity is selected to enhance the shock absorption performance. More preferably, the expansion coefficient of the expansion layer 106 is greater than 5×10-4 / °C. Selecting a material with a relatively large thermal expansion coefficient and moderate hardness to make the expansion layer 106 will be beneficial to reducing the assembly difficulty.

[0052] Preferably, both ends of the bolt 107 are buried in the surface of the blade backing plate 103 to reduce surface interference and facilitate positioning and assembly.

[0053] Figure 3 The flowchart of the fan blade assembly method according to an embodiment of the present invention is shown. As shown in the figure, the present invention also provides a fan blade assembly method applicable to the aforementioned fan blade assembly structure 100. The fan blade assembly method includes the steps:

[0054] S1, freeze the blade backing plate 103 at a low temperature. Specifically, it is to put the blade backing plate 103 into a low-temperature environment for freezing and cooling to significantly reduce the size of the expansion layer 106. Such treatment enables the blade backing plate 103 to be easily installed in the installation groove 110 of the fan disk 101.

[0055] S2, put the blade backing plate 103 frozen at a low temperature into the installation groove 110 of the fan disk 101, and insert the blade root 109 of the fan blade 102 into the installation groove 110. Assemble according to the structure of the fan blade 102.

[0056] S3. The blade backing plate 103 returns to the room temperature of the assembly chamber so that the blade backing plate 103 has an interference fit with the mounting groove 110. During the process of returning to room temperature, the size of the expansion layer 106 gradually increases, enabling the blade backing plate 103 to have an interference fit with the fan disk 101 and the blade root 109, and making the overall structure stable, so as to achieve the functions of shock absorption and wear resistance of the blade backing plate 103.

[0057] A fan blade assembly structure and an assembly method provided by the present invention can effectively reduce the assembly difficulty, improve the shock absorption performance and wear resistance of the blade backing plate, and achieve a certain degree of noise reduction, weight reduction, and the function of assisting the dynamic balance of the fan rotor. It has the following advantages:

[0058] 1. The blade backing plate adopts a three-layer composite structure. The upper and lower layers are hard wear-resistant layers, which play the roles of wear resistance and fitting, and can assist in weight reduction and dynamic balance; the middle layer is an expansion layer, and a material with a relatively large coefficient of thermal expansion and moderate hardness is selected. While reducing the assembly difficulty, it can reduce weight and enhance the shock absorption performance.

[0059] 2. Low-temperature freezing assembly is adopted to achieve an interference fit after returning to room temperature.

[0060] It is obvious to those skilled in the art that various modifications and variations can be made to the above exemplary embodiments of the present invention without departing from the spirit and scope of the present invention. Therefore, it is intended that the present invention cover the modifications and variations of the present invention that fall within the scope of the appended claims and their equivalent technical solutions.

Claims

1. A fan blade assembly structure, suitable for an aircraft engine, the fan blade assembly structure comprising: A fan tray having a mounting slot; A fan blade, the root of which is installed in the installation groove; A blade pad is arranged in the installation groove. The blade pad is a layered structure, including a first hard wear-resistant layer and a second hard wear-resistant layer. An expansion layer is provided between the first and second hard wear-resistant layers. The first hard wear-resistant layer fits the bottom surface of the blade root, and the second hard wear-resistant layer fits the fan disk. The first, second hard wear-resistant layers and the expansion layer are fixed by bolts.

2. The fan blade assembly structure according to claim 1, characterized in that: The first and second hard wear-resistant layers are made of resin-based composite materials, or are the same as the material used to make the fan blades.

3. The fan blade assembly structure according to claim 1, characterized in that: Weight-reducing grooves are provided on the first and second hard wear-resistant layers.

4. The fan blade assembly structure according to claim 1, characterized in that: The expansion layer is made of elastic material.

5. The fan blade assembly structure according to claim 1, characterized in that: The expansion coefficient of the expansion layer is greater than 5×10 -4 / ℃.

6. The fan blade assembly structure according to claim 1, characterized in that: Both ends of the bolt are embedded in the surface of the blade pad.

7. A fan blade assembly method, applicable to the fan blade assembly structure according to claim 1, characterized in that: The fan blade assembly method comprises the steps of: S1, freezing the blade pad at low temperature; S2, placing the cryogenically frozen blade pad into the mounting groove of the fan disk, and installing the blade root of the fan blade into the mounting groove; S3, the blade pad is restored to the room temperature of the assembly room so that the blade pad is interference fit with the installation groove.

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