Engine fairing

Abstract

The invention belongs to the technical field of aero-engine fans / air compressors, and discloses an engine fairing which comprises a fairing body and a connecting structure. The fairing body comprises a front conical section and a rear arc-shaped section, a plurality of bolt holes are evenly formed in the front section of the rear arc-shaped section in the circumferential direction, and the tail end of the rear arc-shaped section is in lap joint with the outer edge of the wheel disc. The connecting structure comprises an adapter shaft, the large-diameter end of the adapter shaft is fixed to the bolt hole through a first connecting assembly, and the small-diameter end of the adapter shaft is pressed and fixed to the fan shaft and the end face of the center of the wheel disc through a second connecting assembly. The engine fairing is simple in structure, easy to achieve and good in assembling performance and reliability.

Description

Technical Field

[0001] The invention belongs to the technical field of aircraft engine fans / compressors and relates to an engine fairing. Background Art

[0002] The engine fairing is located at the front end of the fan, also known as the intake cone, which provides an intake flow path for the fan. Since it is located at the front end of the intake part of the engine, it is required to have an anti-icing function. At present, for the convenience of processing or anti-icing needs, the fairing is usually designed into two parts, namely the conical or elliptical part of the front section and the conical part of the rear section. The front section and the rear section are connected as one by bolts, and then the entire fairing is connected to the front end of the fan disk by bolts. When assembling this structure, the bolts at the fairing mounting edge are installed into the bolt holes from the rear end to the front, and the nuts are tightened at the front end. Therefore, it is necessary to design the fairing mounting edge at the edge of the disk and leave enough disk edge thickness and space for axial mounting bolts, so that there is a large centrifugal load at the edge of the disk. However, when it comes to small-sized fan disks, this type of structure fairing has the disadvantage of insufficient design space. In addition, the connecting bolts and bolt holes of the fairing and the disk of this structure are located near the leading edge of the blade, which have a large disturbance and influence on the airflow entering the fan flow channel. Summary of the invention

[0003] In order to solve the technical problems of the existing two-stage structure fairing, such as airflow disturbance, insufficient design space and large centrifugal load at the edge of the wheel, the present invention discloses a novel engine fairing, which includes a fairing body and a connecting structure.

[0004] The fairing body includes a front conical section and a rear arc section, the front section of the rear arc section is evenly provided with a plurality of bolt holes along the circumferential direction, and the end of the rear arc section overlaps the outer edge of the wheel. The connection structure includes an adapter shaft, the large diameter end of the adapter shaft is fixed to the bolt hole through a first connection component, and the small diameter end is pressed and fixed to the fan shaft and the end surface of the wheel center through a second connection component.

[0005] Furthermore, a mounting portion is provided on the inner wall of the front section of the rear arc section, and the mounting portion includes a first mounting edge and a second mounting edge, the first mounting edge is parallel to the axis of the fairing body, the second mounting edge is perpendicular to the axis of the fairing body, and the bolt hole is opened on the second mounting edge.

[0006] Furthermore, the mounting portion further includes a first stop located at the connection between the first mounting edge and the second mounting edge, and the first stop overlaps the large diameter end of the adapter shaft.

[0007] Furthermore, a second stop is provided at the end of the rear arc section, and the second stop is overlapped with the outer edge of the wheel disc.

[0008] Further, the adapter shaft comprises an annular adapter plate, and the angle between the annular adapter plate and the axis of the fairing body is 40° to 60°;

[0009] A first transfer edge is provided at the large diameter end of the annular transfer plate, and an assembly hole is provided on the first transfer edge to match each of the bolt holes. A second transfer edge is provided at the small diameter end of the annular transfer plate, and the inner wall of the second transfer edge contacts the fan shaft, and the edge of the second transfer edge contacts and fits with the end face of the wheel center.

[0010] Furthermore, the annular adapter plate is provided with ventilation holes.

[0011] Furthermore, a clamping ring groove is provided on a surface of the first transition edge that contacts the inner wall of the rear arc-shaped segment, and a clamping ring is provided in the clamping ring groove.

[0012] Furthermore, the second connecting assembly includes a nut and a locking plate.

[0013] Furthermore, the first connecting assembly includes a D-head bolt and a self-locking nut.

[0014] Furthermore, the angle between the taper of the front conical section and the axis of the fairing body is 23° to 28°, the axial length of the front conical section is 55% to 65% of the axial length of the fairing body, and the axial distance between the bolt hole and the outer edge of the wheel disc is 35% to 45% of the axial length of the fairing body.

[0015] Compared with the prior art, the beneficial effects that can be achieved by at least one of the above-mentioned technical solutions adopted in the embodiments of this specification include at least: the engine fairing structure of the present invention is simple and easy to implement, and has good assembly performance and reliability.

[0016] By designing the fairing body and the adapter shaft, the fairing body is connected to the fan shaft and the impeller through the connecting assembly, and the axial positioning and torque transmission of the fairing are achieved through the adapter shaft. At the same time, the conical surface of the front conical section and the arc-shaped outer cylindrical surface of the rear arc section are combined, so that it has both anti-icing function and good aerodynamic shape, and the design of the second stop at the end of the rear arc section achieves good centering.

[0017] At the same time, the position of the bolt holes on the fairing body is optimized from the position close to the wheel rim in the traditional design to a position far away from the wheel rim, reducing the disturbance of the bolt holes and bolts to the airflow entering the fan flow passage, while providing sufficient bolt assembly space, eliminating the installation edge of the wheel rim, simplifying the wheel structure, and reducing the thickness of the wheel rim and the centrifugal load.

[0018] Furthermore, the ventilation holes are designed on the adapter shaft to prevent the formation of dead space in the inner cavity of the fairing. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a cross-sectional schematic diagram of an engine fairing disclosed in an embodiment of the present invention;

[0021] Figure 2 It is a cross-sectional schematic diagram of a fairing body disclosed in an embodiment of the present invention;

[0022] Figure 3 It is a schematic diagram of the connection between the fairing body and the adapter shaft via the first connecting assembly disclosed in an embodiment of the present invention;

[0023] Among them, 2. adapter shaft; 3. wheel disc; 4. fan shaft; 5. nut; 6. locking plate; 7. D-head bolt; 8. self-locking nut; 9. retaining ring; 11. second mounting edge; 12. bolt hole; 13. second stopper; 14. front conical section; 15. rear arc section; 16. first mounting edge; 17. first stopper; 21. annular adapter plate; 22. first adapter edge; 23. assembly hole; 24. second adapter edge; 241. first matching cylinder; 242. second matching cylinder; 25. vent hole; 26. third stopper; 27. bolt stop cylinder; 28. nut tightening surface. DETAILED DESCRIPTION

[0024] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0025] The following describes the implementation methods of the present application through specific specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the following embodiments and the features of the embodiments can be combined with each other in the absence of conflict. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0026] In the description of this embodiment, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply 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 understood as a limitation on the invention.

[0027] In addition, the terms "first", "second", "third", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more features. In the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0028] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present disclosure. The illustrations only show components related to the present disclosure rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0029] The embodiment of the present invention discloses a novel engine fairing, which comprises a fairing body and a connecting structure, wherein the connecting structure is used to connect the fairing body with a wheel disc 3 and a fan shaft 4.

[0030] Among them, see Figure 1 and Figure 2 As shown, the fairing body is an integral structure, including a front conical section 14 and a rear arc section 15. The front conical section 14 has no bleed air anti-icing structure, and the anti-icing effect is achieved by the centrifugal force of the conical surface structure under the action of rotation. The rear arc section 15 is close to the wheel disc 3. The front conical section 14 and the rear arc section 15 are smoothly connected, and the entire pneumatic flow channel of the fairing is adapted to the wheel disc flow channel. The front section of the rear arc section 15 is evenly provided with a plurality of bolt holes 12 along the circumferential direction, and the end of the rear arc section 15 overlaps the outer edge of the wheel disc 3.

[0031] See also Figure 1 As shown, the connection structure includes an adapter shaft 2, which is a rotating part. The large diameter end of the adapter shaft 2 is fixed to the bolt hole 12 through a first connection component, and the small diameter end is pressed and fixed to the fan shaft 4 and the end surface of the center of the wheel disc 3 through a second connection component. The large diameter end is used to connect with the fairing body, and the small diameter end is used to fit with the center of the wheel disc 3 for axial positioning.

[0032] Further, see Figure 1 , Figure 2 and Figure 3 As shown, a mounting portion is provided on the inner wall of the front section of the rear arc section 15, and the mounting portion includes a first mounting edge 16 and a second mounting edge 11, the first mounting edge 16 is parallel to the axis of the fairing body, the second mounting edge 11 is perpendicular to the axis of the fairing body, and the bolt hole 12 is opened on the second mounting edge 11.

[0033] Further, see Figure 1 , Figure 2 and Figure 3 As shown, the mounting portion further includes a first stop 17 located at the connection between the first mounting edge 16 and the second mounting edge 11 , and the first stop 17 overlaps the large diameter end of the adapter shaft 2 .

[0034] Further, see Figure 1 , Figure 2 and Figure 3 As shown, the end of the rear arc section 15 is provided with a second stop 13, and the second stop 13 overlaps the outer edge of the wheel disc 3, and the second stop 13 can play a positioning / centering role. It should be noted that the fairing body and the edge of the wheel disc 3 retain an axial gap of 0.3mm to 0.6mm to prevent over-positioning.

[0035] Further, see Figure 1 As shown, the adapter shaft 2 includes an annular adapter plate 21, and the angle between the annular adapter plate 21 and the axis of the fairing body is 40° to 60°. The large diameter end of the annular adapter plate 21 is provided with a first adapter edge 22, and the first adapter edge 22 is provided with an assembly hole 23 that matches each of the bolt holes 12. The small diameter end of the annular adapter plate 21 is provided with a second adapter edge 24, and the inner wall of the second adapter edge 24 contacts the fan shaft 4, and the edge of the second adapter edge 24 contacts and fits with the end surface of the center of the wheel 3.

[0036] Furthermore, to prevent the inner cavity of the fairing from becoming a dead space, see Figure 1 As shown, the annular adapter plate 21 is provided with a vent hole 25. In this specific embodiment, the vent hole 25 can be set to one or more.

[0037] Further, see Figure 1 and Figure 3 As shown, a clamping ring groove is provided on the first transition edge 22 and on the side in contact with the inner wall of the rear arc-shaped section 15, and a clamping ring 9 is provided in the clamping ring groove.

[0038] Further, see Figure 1 and Figure 3As shown, the second connecting assembly includes a nut 5 and a locking plate 6.

[0039] Further, see Figure 1 As shown, the first connecting assembly includes a D-head bolt 7 and a self-locking nut 8.

[0040] Furthermore, the angle between the taper of the front conical section 14 and the axis of the fairing body is 23° to 28°, the axial length of the front conical section 14 is 55% to 65% of the axial length of the fairing body, and the axial distance between the bolt hole 12 and the outer edge of the wheel disc 3 is 35% to 45% of the axial length of the fairing body.

[0041] During assembly, first install the wheel disc 3 into the fan shaft 4, then install the D-head bolt 7 into the assembly hole 23 of the adapter shaft 2, install the retaining ring 9 into the retaining groove of the D-head bolt 7, install the adapter shaft 2 with the D-head bolt 7 onto the fan shaft 4, make the inner wall surface of the second adapter edge 24 close to the fan shaft 4, make the end face of the second adapter edge 24 of the adapter shaft 2 axially match the end face close to the center of the wheel disc 3, install the locking plate 6, screw the nut 5 into the thread of the fan shaft 4, and lock the locking plate 6; then install the fairing body onto the adapter shaft 2, align the bolt hole 12 of the fairing body with the screw of the D-head bolt 7, tighten the self-locking nut 8 after the fairing body is assembled in place, and the assembly is completed.

[0042] When designing the fairing body, the inner surface of the fairing is contoured to the flow channel surface so that the part maintains a certain wall thickness, and the part wall thickness should meet the strength design requirements.

[0043] The second mounting edge 11 is arranged at the inner wall of the fairing. The height dimension H of the second mounting edge 11 ensures that there is enough structural space to install the adapter shaft 2 and the D-head bolt 7. When designing, the size of the D-head bolt 7 is first selected, and then the height of the second mounting edge 11 is set according to the selected diameter of the D-head bolt 7. In general, in order to ensure that there is enough connection wall thickness on both sides of the bolt hole 12, the size of the second mounting edge 11 needs to be 6mm to 7mm larger than the diameter of the D-head bolt 7. If the D-head bolt 7 of MJ5 is selected, its size should be 11mm to 12mm. The diameter of the bolt hole 12 is designed according to the size of the D-head bolt 7. Generally, the diameter of the bolt hole 12 is 0.2mm to 0.3mm larger than the thread diameter of the D-head bolt 7. Furthermore, the bolt diameter design on the fairing body should not be too large, and it is sufficient to meet the connection and torque transmission requirements, because the bolt hole 12 needs to penetrate the aerodynamic surface of the fairing, and the bolt hole 12 is too large. The influence on the aerodynamic surface is also greater. The bolt holes 12 are evenly arranged in 8 or 10. The second stop 13 (i.e., annular stop) designed near the wheel end of the fairing body is used to cooperate with and center the wheel 3. The diameter of the second stop 13 is determined according to the rim size of the wheel 3. During the design, a small gap of less than 0.03mm on one side is maintained.

[0044] When designing the adapter shaft 2, the adapter shaft 2 is a rotating part with a conical surface. The angle between the conical surface of the annular adapter disk 21 and the axis is in the range of 40° to 60°. The end with a larger diameter is provided with a third stop 26 for connection, which maintains a small clearance of less than 0.03 mm on a single side in the radial direction with the second mounting edge 11 of the fairing body. A groove is provided on the end face of the first adapter edge 22 that is in contact with the fairing body to install the retaining ring 9. A bolt stop cylinder 27 can also be provided on the adapter shaft 2. The bolt stop cylinder 27 is used to prevent the D-head bolt 7 from rotating. The second adapter edge 24 including the first mating cylinder 241 and the second mating cylinder 242 is arranged at the end with a smaller diameter on the adapter shaft 2. The first mating cylinder 241 is used to connect with the fan shaft to transmit torque. The diameter of the first mating cylinder 241 is designed to maintain an interference fit of 0.01mm to 0.03mm on one side of the fan shaft. To facilitate the disassembly of parts, the axial mating length of the first mating cylinder 241 should not be too long, and the reliable transmission of torque is ensured. The recommended mating length is 3mm to 5mm. The second mating cylinder 242 is arranged at one end of the first mating cylinder 241. The second mating cylinder 242 is used to press with the center of the wheel disc to play an axial positioning role. A nut pressing surface 28 is arranged on the adapter shaft 2. The nut pressing surface 28 is used for the tight fit and pressing of the locking plate 6 when the nut 5 is tightened. The axial position of the nut pressing surface 28 should protrude from the left end face of the fan shaft by about 1mm to 2mm. The axial distance of the nut pressing surface 28 is designed to keep a certain gap between the fairing and the wheel disc edge after assembly to prevent the fairing from being over-positioned. The gap is in the range of 0.3mm to 0.6mm. The diameter of the vent hole 25 can be designed to be 2mm to 3mm.

[0045] The engine fairing of the present invention has a simple structure, is easy to implement, and has good assembly performance and reliability.

[0046] It has the following advantages:

[0047] 1. Through the design of the fairing body and the adapter shaft, the fairing body is connected to the fan shaft and the impeller through the connecting assembly, and the axial positioning and torque transmission of the fairing are realized through the adapter shaft. At the same time, the conical surface of the front conical section and the arc-shaped outer cylindrical surface of the rear arc section are combined, so that it has both anti-icing function and good aerodynamic shape, and the design of the second stop at the end of the rear arc section realizes good centering.

[0048] 2. The position of the bolt holes on the fairing body is optimized from the position close to the wheel rim in the traditional design to a position far away from the wheel rim, which reduces the disturbance of the bolt holes and bolts to the airflow entering the fan flow channel, while providing sufficient bolt assembly space, eliminating the installation edge of the wheel rim, simplifying the wheel structure, and reducing the thickness of the wheel rim and the centrifugal load.

[0049] 3. The vent hole is designed on the adapter shaft to prevent the formation of dead space in the inner cavity of the fairing.

[0050] Obviously, those skilled in the art should understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the embodiments of the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0051] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. An engine cowling, characterized in that: include; A fairing body, the fairing body comprising a front conical section (14) and a rear arc section (15), the front section of the rear arc section (15) being evenly provided with a plurality of bolt holes (12) along the circumferential direction, and the end of the rear arc section (15) being overlapped with the outer edge of the wheel disc (3); A connection structure, the connection structure comprising an adapter shaft (2), the large diameter end of the adapter shaft (2) being fixed to the bolt hole (12) via a first connection component, and the small diameter end being pressed and fixed to the fan shaft (4) and the center end surface of the wheel disc (3) via a second connection component.

2. The engine cowling according to claim 1, characterized in that: A mounting portion is provided on the inner wall of the front section of the rear arc section (15), and the mounting portion comprises a first mounting edge (16) and a second mounting edge (11), the first mounting edge (16) is parallel to the axis of the fairing body, the second mounting edge (11) is perpendicular to the axis of the fairing body, and the bolt hole (12) is provided on the second mounting edge (11).

3. The engine cowling according to claim 2, characterized in that: The mounting portion further comprises a first stop (17) located at the connection between the first mounting edge (16) and the second mounting edge (11), and the first stop (17) overlaps the large diameter end of the adapter shaft (2).

4. The engine cowling according to claim 1, characterized in that: A second stop (13) is provided at the end of the rear arc section (15), and the second stop (13) overlaps the outer edge of the wheel disc (3).

5. The engine cowling according to claim 1, characterized in that: The adapter shaft (2) comprises an annular adapter plate (21), and the angle between the annular adapter plate (21) and the axis of the fairing body is 40° to 60°; The large-diameter end of the annular adapter plate (21) is provided with a first adapter edge (22), and the first adapter edge (22) is provided with an assembly hole (23) that matches each of the bolt holes (12). The small-diameter end of the annular adapter plate (21) is provided with a second adapter edge (24), the inner wall of the second adapter edge (24) is in contact with the fan shaft (4), and the edge of the second adapter edge (24) is in contact with the end surface of the center of the wheel disc (3).

6. The engine cowling according to claim 5, characterized in that: The annular adapter plate (21) is provided with a vent hole (25).

7. The engine cowling according to claim 5, characterized in that: A clamping ring groove is provided on the first transition edge (22) on a side in contact with the inner wall of the rear arc-shaped section (15), and a clamping ring (9) is provided in the clamping ring groove.

8. The engine cowling according to claim 1, characterized in that: The second connecting assembly comprises a nut (5) and a locking plate (6).

9. The engine cowling according to claim 1, characterized in that: The first connecting assembly comprises a D-head bolt (7) and a self-locking nut (8).

10. The engine cowling according to any one of claims 1 to 9, characterized in that: The angle between the taper of the front conical section (14) and the axis of the fairing body is 23° to 28°, the axial length of the front conical section (14) is 55% to 65% of the axial length of the fairing body, and the axial distance between the bolt hole (12) and the outer edge of the wheel disc (3) is 35% to 45% of the axial length of the fairing body.

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