Fan blade mounting structure, mounting method, and open rotor engine

Abstract

The present invention relates to a fan blade mounting structure, a mounting method, and an open rotor engine. Among them, the fan blade mounting structure is used to mount a fan blade on a hub. The fan blade includes a blade shank, and the blade shank is mounted on the hub through the fan blade mounting structure. The fan blade mounting structure includes: a bearing device, which includes, from the inside to the outside in the radial direction: a bearing inner ring, rolling elements, and a bearing outer ring. The rolling elements are respectively and rotatably connected to the bearing inner ring and the bearing outer ring at both ends; the bearing inner ring is used for interference fit with the blade shank, and the bearing outer ring is used for connection with the inner wall of the hole of the hub; wherein, the bearing outer ring includes an upper section, a middle section, and a lower section that are sequentially distributed along the axial direction.

Description

Technical Field

[0001] The present invention relates to a fan blade mounting structure, a mounting method, and an open rotor engine. Background Art

[0002] An open rotor engine is a new type of engine between turboprop and turbofan, also known as a propfan engine or a ducted fanless engine. The open rotor engine can achieve an ultra-high bypass ratio (30 - 90), has a higher propulsion efficiency than a turbofan engine under high subsonic cruise conditions, and has a fuel consumption rate 25% - 30% lower than that of the currently in-service engines. It is an important technical approach to achieve aviation carbon emission reduction.

[0003] The open fan blade is set into the hub hole through a mounting structure, and the blade can rotate in the hub hole driven by a pitch-changing mechanism. The open fan blade has a long radius and large sweep angles at the leading and trailing edges. The bending moment caused by the misalignment between the blade centroid and the rotation axis of the blade root at different pitch angles is also large. The moving blade mounting structure needs to bear huge axial forces (corresponding to centrifugal forces) and radial forces (corresponding to bending moments), as well as the torque transmitted from the pitch-changing mechanism.

[0004] The fan component of the open rotor engine has no outer casing. The airworthiness regulations require that the open fan blade and its mounting structure still have sufficient structural integrity and safety when suffering from accidental situations such as bird strikes. Under extreme conditions, when part of the fan blade flies off after being struck by foreign objects, it may cause the engine to stop. At this time, the blade still needs to be able to rotate and maintain at a suitable pitch angle to ensure flight safety. Specifically, during the operation of the engine, due to inevitable reasons such as foreign object ingestion and fatigue, huge impact and unbalanced loads are generated on the fan rotor. The impact and unbalanced loads generated by the fan rotor are transmitted to the hub through the moving blade mounting structure, and then transmitted to the load-bearing casing through the fulcrum. Excessive impact loads may cause jamming between the blade root and the hub hole, which may cause the fan blade to be at an unfavorable pitch angle, endangering flight safety. Therefore, the fan blade should still be able to rotate and maintain at a suitable pitch angle under impact and unbalanced loads.

[0005] Therefore, there is a need in the art for a fan blade mounting structure, a mounting method, and an open rotor engine to achieve a fan blade mounting structure with heavy load and large impact bearing capacity, so as to ensure sufficient functional integrity after suffering large loads. Summary of the Invention

[0006] One object of the present invention is to provide a fan blade mounting structure.

[0007] One object of the present invention is to provide a mounting method.

[0008] One object of the present invention is to provide an open rotor engine.

[0009] A fan blade mounting structure according to a first aspect of the present invention is used to mount a fan blade on a hub. The fan blade includes a blade shank, and the blade shank is mounted on the hub through the fan blade mounting structure. The fan blade mounting structure includes: a bearing device, which includes, from the inside to the outside in the radial direction: a bearing inner ring, rolling elements, and a bearing outer ring. The rolling elements are respectively rollingly connected to the bearing inner ring and the bearing outer ring at both ends; the bearing inner ring is used for interference fit with the blade shank, and the bearing outer ring is used for connection with the inner wall of the hole of the hub; wherein, the bearing outer ring includes an upper section, a middle section, and a lower section that are sequentially distributed along the axial direction. The upper section of the bearing outer ring cooperates with a pressing member, and the middle section and the lower section cooperate with the inner wall of the hole of the hub. There is a first mechanical weak part between the upper section and the middle section of the bearing outer ring, and the lower section has a second mechanical weak part; the middle section has a first spherical hinge surface, and the inner wall of the hole of the hub has a second spherical hinge surface. The first spherical hinge surface and the second spherical hinge surface cooperate with each other to form a spherical hinge pair, and an energy-absorbing layer is arranged between the first spherical hinge surface and the second spherical hinge surface.

[0010] In one or more embodiments of the fan blade mounting structure, the fan blade mounting structure is coaxial with the blade shank of the fan blade and can simultaneously bear the axial force and the radial force from the fan blade.

[0011] In one or more embodiments of the fan blade mounting structure, the rolling elements include inclined cylindrical rolling elements and spherical rolling elements. The inclined cylindrical rolling elements and the spherical rolling elements are arranged along the axial direction to jointly support the blade shank.

[0012] In one or more embodiments of the fan blade mounting structure, the energy-absorbing layer is an artificial cartilage foam material.

[0013] In one or more embodiments of the fan blade mounting structure, when the fan is in a normal state, the bearing outer ring is relatively fixed to the inner wall of the hole of the hub, and the blade shank can rotate relative to the hub through the rolling elements.

[0014] In one or more embodiments of the fan blade mounting structure, when the impact load transmitted from the fan blade to the bearing outer ring exceeds a threshold value, the first mechanical weak part and / or the second mechanical weak part of the bearing outer ring fails. At this time, the bearing outer ring is connected to the inner wall of the hole of the hub through the spherical hinge pair formed by the inner wall of the hole of the hub and the middle section, so that the bearing outer ring and the inner wall of the hole of the hub can rotate and tilt relative to each other.

[0015] In one or more embodiments of the fan blade mounting structure, when the impact load transmitted from the fan blade to the outer bearing ring exceeds a threshold value, the first mechanically weak part and / or the second mechanically weak part of the outer bearing ring fail, and the relative movement of the ball hinge pair squeezes the energy absorption layer.

[0016] In one or more embodiments of the fan blade mounting structure, when the rollable fit between the rolling elements and the inner bearing ring and the outer bearing ring fails under the action of an impact load, the ball hinge pair between the outer bearing ring and the inner wall of the hole of the hub allows the blade shank to rotate within the hole of the hub.

[0017] According to an installation method of the second aspect of the present invention, the fan blade is installed on the hub by using the fan blade mounting structure introduced above.

[0018] According to an open rotor engine of the third aspect of the present invention, it includes a fan blade mounting structure as introduced above, as well as a fan blade and a hub. The fan blade includes a blade shank, and the blade shank is installed on the hub through the fan blade mounting structure, so that the fan blade is installed and connected to the hub.

[0019] The progressive effect of this case is that it realizes reducing the impact energy transmitted to the hub under large impact loads and preventing blade jamming. Specifically, the progressive effects include but are not limited to:

[0020] 1. Reducing impact load: When the load exceeds the threshold value, the outer bearing ring part is decoupled from the fan hub, realizing ball hinge surface fit between the two through an energy absorption structure, and absorbing impact energy through the energy absorption layer, while reducing the load transmitted to the hub to ensure the safety of the hub.

[0021] 2. Preventing jamming: When the load exceeds the threshold value, the ball hinge surface fit allows the blade shank to rotate with the fan blade mounting structure together with the fan hub, preventing the occurrence of jamming between the blade shank and the hub hole due to the failure of the rollable fit between the rolling elements and the inner and outer bearing rings. Description of the Drawings

[0022] The above-mentioned and other features, properties and advantages of the present invention will become more obvious through the following description in conjunction with the drawings and embodiments. It should be noted that the drawings are only examples, and they are not drawn according to the condition of equal proportion, and should not be used to limit the actual protection scope required by the present invention, where:

[0023] Figure 1 is a schematic structural diagram of an open rotor engine of an embodiment.

[0024] Figure 2 is a schematic structural diagram of a fan blade mounting structure of an embodiment.

[0025] Reference numerals:

[0026] 100 - Open rotor engine

[0027] 10 - Fan blade mounting structure

[0028] 20 - Fan blade

[0029] 30 - Hub

[0030] 40 - Petiole

[0031] 50 - Inner wall of the hole in the hub

[0032] 501 - Second spherical hinge surface

[0033] 1 - Bearing device

[0034] 11 - Bearing inner ring

[0035] 12 - Rolling element

[0036] 121 - Obliquely arranged cylindrical rolling element

[0037] 122 - Spherical rolling element

[0038] 13 - Bearing outer ring

[0039] 131 - Upper section

[0040] 132 - Middle section

[0041] 1320 - First spherical hinge surface

[0042] 133 - Lower section

[0043] 141 - First mechanically weak part

[0044] 142 - Second mechanically weak part

[0045] 15 - Energy - absorbing layer

[0046] 2 - Compressing part. Detailed implementation manners

[0047] Reference will now be made in detail to the various embodiments of the present application, examples of which are shown in the accompanying drawings and described as follows. Although the present application will be described in conjunction with exemplary embodiments, it should be understood that this specification is not intended to limit the present application to those exemplary embodiments. On the contrary, the present application is intended to cover not only these exemplary embodiments, but also various alternative forms, modifications, equivalents and other embodiments that may be included within the spirit and scope of the present application as defined by the appended claims.

[0048] In addition, it should be understood that terms such as "one embodiment", "an embodiment", and / or "some embodiments", "one or more embodiments" mean a certain feature, structure, or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that the "one embodiment" or "an embodiment" or "some embodiments" or "one or more embodiments" mentioned twice or more at different positions in this specification do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of the present application can be appropriately combined.

[0049] In the description of the embodiments of the present application, technical terms "first", "second", such as the first paragraph, the second paragraph, etc., are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order, or primary-secondary relationship of the indicated technical features.

[0050] In the subsequent description, the orientation or positional relationship indicated by terms such as "upstream", "downstream" or other orientation terms is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the indicated device or component must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present application. In addition, in the specification of the present application, "upstream", "downstream", "front", and "rear" are distinguished based on the general flow direction of air during the operation of the engine, that is, during the operation of the engine, air generally flows from "upstream" to "downstream", from "front" to "rear", and this direction is also roughly the direction from "intake air" to "exhaust air" of the engine turbine.

[0051] As Figure 1 shown, in some embodiments, the open rotor engine 100 includes a fan blade mounting structure 10, fan blades 20, a hub 30, a pitch changing device 60, an inlet cone 70, and the fan blades 20 include blade roots 40.

[0052] The inlet cone 70 is generally located at the very front end of the open rotor engine 100, and the fan blades 20 are adjacent to the inlet cone 70. The blade roots 40 of the fan blades 20 are connected to the hub 30 through the fan blade mounting structure 10 to be introduced in detail in the following embodiments; the end of the blade root 40 cooperates with the pitch changing device 60 to realize the axial rotation of the blade root 40 driven by the pitch changing device 60 to adjust the pitch angle of the fan blades 20.

[0053] The fan blades 20 of the open rotor engine 100 generally adopt a wide chord, thin airfoil, and long span design. When they are subjected to impacts and unbalanced loads in unexpected situations such as bird strikes, the impacts are transmitted from the blade roots 40 to the hub 30 through the fan blade mounting structure 10, and further transmitted to the fulcrum and the load-bearing casing through the fan shaft 80.

[0054] ReferenceFigure 1 and Figure 2 As shown, the fan blade mounting structure 10 is coaxial with the blade handle 40 and can simultaneously bear the axial force (corresponding to the centrifugal force) and the radial force (corresponding to the bending moment) from the fan blade 20.

[0055] Continue to refer to Figure 1 and Figure 2 As shown, in some embodiments, the fan blade mounting structure 10 includes: a bearing device 1, which includes, from the inside to the outside in the radial direction: a bearing inner ring 11, rolling elements 12, and a bearing outer ring 13. The rolling elements 12 are respectively rollingly connected to the bearing inner ring 11 and the bearing outer ring 13 at both ends.

[0056] The bearing inner ring 11 is used for interference fit with the blade handle 40.

[0057] The bearing outer ring 13 is used for connection with the inner wall 50 of the hole of the hub; wherein, the bearing outer ring 13 includes an upper section 131, a middle section 132, and a lower section 133 that are sequentially distributed along the axial direction. The upper section 131 of the bearing outer ring cooperates with the pressing member 2. The pressing member 2 can be, for example, the pressing nut shown in the figure, but is not limited thereto. The middle section 132 and the lower section 133 cooperate with the inner wall 50 of the hole of the hub. There is a first mechanical weak part 141 between the upper section 131 and the middle section 132 of the bearing outer ring, and the lower section 133 has a second mechanical weak part 142.

[0058] The specific structures of the first mechanical weak part 141 and the second mechanical weak part 142, for example Figure 2 As shown, there may be an arc-shaped thinning section between the upper section 131 and the middle section 132 with a thickness thinner than that of the upper section 131 and the middle section 132, and the lower section 133 has an arc-shaped thinning section with a thickness thinner than that of the lower section 133, but is not limited thereto. It may also be other shapes of thinning, or in the form of a material that is weaker than the upper section 131, the middle section 132, and the lower section 133, and is not limited thereto.

[0059] The middle section 132 has a first spherical hinge surface 1320, and the inner wall 50 of the hole of the hub has a second spherical hinge surface 501. The first spherical hinge surface 1320 and the second spherical hinge surface 501 cooperate with each other to form a spherical hinge pair, and an energy absorption layer 15 is provided between the first spherical hinge surface 1320 and the second spherical hinge surface 501.

[0060] The beneficial effects of adopting the above embodiments are as follows: reducing the impact energy transmitted to the hub under large impact loads and preventing blade jamming. Specifically, the beneficial effects include, but are not limited to: being able to reduce the impact load. When the load exceeds the threshold, the outer ring part of the bearing is decoupled from the fan hub, and a ball-joint surface fit is achieved between the two through an energy-absorbing structure, and the impact energy is absorbed through the energy-absorbing layer, while reducing the load transmitted to the hub to ensure the safety of the hub. In addition, it can also achieve the effect of anti-jamming. When the load exceeds the threshold, the ball-joint surface fit allows the petiole to drive the fan blade mounting structure to rotate with the fan hub, preventing the occurrence of jamming between the petiole and the hub hole due to the failure of the rolling elements to roll-fit with the inner and outer rings of the bearing.

[0061] In some embodiments, the material of the energy-absorbing layer 15 can be artificial cartilage foam material (ACF). Specifically, it is a typical soft matrix hybrid pore material, and at the same time, it is a bionic metamaterial with a three-dimensional ultramicrostructure designed based on the function and structure of human knee cartilage. There are micron-sized holes inside the material, and there is a certain connection between the holes. The surfaces of the holes are distributed with groove-like protrusions, and the heights of these are all at the nanometer level. The beneficial effect of this is that it can better achieve the effect of energy absorption.

[0062] In some embodiments, the specific structure of the rolling elements 12 can be that the rolling elements 12 include inclined cylindrical rolling elements 121 and spherical rolling elements 122. The inclined cylindrical rolling elements 121 and the spherical rolling elements 122 are arranged axially to jointly support the petiole 40. The beneficial effect of this is that it can provide a more stable support effect.

[0063] In some embodiments, when the fan is in a normal state, the outer ring 13 of the bearing is relatively fixed to the inner wall 50 of the hole of the hub, without relative sliding. The petiole 40 can rotate relative to the hub 30 through the rolling elements 12, that is, the relative rotation between the petiole 40 and the hub hole required for adjusting the pitch angle of the fan blade 20 is realized by the rolling elements 12 in the fan blade mounting structure 10 to ensure the normal operation of the fan blade 20.

[0064] When the impact load transmitted from the fan blade 20 to the outer ring 13 of the bearing exceeds the threshold, the first mechanically weak part 141 and / or the second mechanically weak part 142 of the outer ring 13 of the bearing fails. That is, at this time, the upper section 131 and the lower section 133 of the outer ring 13 of the bearing are disconnected from the inner wall 50 of the hole of the hub, and at this time, the outer ring 13 of the bearing and the inner wall 50 of the hole of the hub form a ball-joint pair connection through the inner wall 50 of the hole of the hub and the middle section 132, so that the outer ring 13 of the bearing and the inner wall 50 of the hole of the hub can rotate and tilt relative to each other, and at the same time, it can provide partial restraint to ensure that the petiole 40 will not fly out.

[0065] In addition, when the impact load transmitted from the fan blade 20 to the outer bearing ring 13 exceeds the threshold value, the first mechanically weak part 141 and / or the second mechanically weak part 142 of the outer bearing ring 13 fail, and the relative movement of the ball hinge pair squeezes the energy absorption layer 15 to absorb the impact energy and reduce the load transmitted to the hub 30.

[0066] That is, the failure of the first mechanically weak part 141 and / or the second mechanically weak part 142 on the outer bearing ring 13 reduces the load transmission path from the blade handle 40 to the hub 30 on the one hand, and the relative movement of the ball hinge pair squeezes the energy absorption layer 15 to absorb the impact energy and reduce the load transmitted to the hub 30, ensuring the safety of the hub 30.

[0067] In addition, when the rollable fit between the rolling elements 12 and the inner bearing ring 11 and the outer bearing ring 13 fails under the action of an impact load, the ball hinge pair between the outer bearing ring 13 and the inner wall 50 of the hole of the hub allows the blade handle 40 to rotate in the hole of the hub 30, that is, the ball hinge pair allows the blade handle 40 to still rotate in the hub hole under the drive of the pitch-changing device 60, so that the fan blade 20 can be adjusted to an appropriate pitch angle to ensure the safety of the engine.

[0068] It can be understood that, as described above, the present application also provides an installation method, and the fan blade 20 is installed on the hub 30 by using the fan blade installation structure 10 introduced in the above embodiments.

[0069] In summary, the beneficial effects of adopting the above embodiments are to reduce the impact energy transmitted to the hub under large impact loads and prevent blade jamming. Specifically, the beneficial effects include but are not limited to:

[0070] 1. Reducing impact load: When the load exceeds the threshold value, the outer bearing ring part is decoupled from the fan hub, realizing ball hinge surface fit between the two through the energy absorption structure, and absorbing the impact energy through the energy absorption layer, while reducing the load transmitted to the hub and ensuring the safety of the hub.

[0071] 2. Anti-jamming: When the load exceeds the threshold value, the ball hinge surface fit allows the blade handle to rotate with the fan blade installation structure together with the fan hub, preventing the occurrence of jamming between the blade handle and the hub hole due to the failure of the rollable fit between the rolling elements and the inner and outer bearing rings.

[0072] Although the present invention is disclosed as above in the above embodiments, it is not used to limit the present invention. Any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present invention. Therefore, any modification, equivalent change and decoration made to the above embodiments according to the technical essence of the present invention without departing from the technical solution of the present invention shall fall within the protection scope defined by the claims of the present invention.

Claims

1. A fan blade mounting structure (10), characterized in that, For mounting a fan blade (20) to a hub (30), the fan blade (20) includes a blade shank (40), and the blade shank (40) is mounted to the hub (30) through the fan blade mounting structure (10). The fan blade mounting structure (10) includes: A bearing device (1) which includes, from inside to outside in the radial direction: a bearing inner ring (11), rolling elements (12), and a bearing outer ring (13). The rolling elements (12) are respectively in rolling connection with the bearing inner ring (11) and the bearing outer ring (13) at both ends; The bearing inner ring (11) is used for interference fit with the blade shank (40); The bearing outer ring (13) is used for connection with the inner wall of the hole of the hub (50); Wherein, the bearing outer ring (13) includes an upper section (131), a middle section (132), and a lower section (133) which are sequentially distributed along the axial direction. The upper section (131) of the bearing outer ring cooperates with a pressing member (2), and the middle section (132) and the lower section (133) cooperate with the inner wall of the hole of the hub (50). There is a first mechanical weak part (141) between the upper section (131) and the middle section (132) of the bearing outer ring, and the lower section (133) has a second mechanical weak part (142); The middle section (132) has a first spherical hinge surface (1320), and the inner wall of the hole of the hub (50) has a second spherical hinge surface (501). The first spherical hinge surface (1320) and the second spherical hinge surface (501) cooperate with each other to form a spherical hinge pair, and an energy absorption layer (15) is arranged between the first spherical hinge surface (1320) and the second spherical hinge surface (501); The fan blade mounting structure (10) is coaxial with the blade shank of the fan blade and can simultaneously bear the axial force and the radial force from the fan blade (20); The rolling elements (12) include inclined cylindrical rolling elements (121) and spherical rolling elements (122). The inclined cylindrical rolling elements (121) and the spherical rolling elements (122) are arranged along the axial direction to jointly support the blade shank (40); When the fan is in a normal state, the bearing outer ring (13) is relatively fixed to the inner wall of the hole of the hub (50), and the blade shank (40) can rotate relative to the hub (30) through the rolling elements (12); When the rollable fit between the rolling elements (12) and the bearing inner ring (11) and the bearing outer ring (13) fails under the action of an impact load, the spherical hinge pair between the bearing outer ring (13) and the inner wall of the hole of the hub (50) allows the blade shank (40) to rotate in the hole of the hub (30).

2. The fan blade mounting structure (10) according to claim 1, wherein, The energy absorption layer (15) is an artificial cartilage foam material.

3. The fan blade mounting structure (10) according to claim 1, characterized in that, When the impact load transmitted from the fan blade (20) to the outer bearing ring (13) exceeds a threshold value, the first mechanically weak part (141) and / or the second mechanically weak part (142) of the outer bearing ring (13) fails. At this time, a spherical hinge pair is formed between the outer bearing ring (13) and the inner wall (50) of the hole of the hub through the inner wall (50) of the hole of the hub and the middle section (132), so that the outer bearing ring (13) and the inner wall (50) of the hole of the hub can rotate and tilt relative to each other.

4. The fan blade mounting structure (10) according to claim 3, wherein, When the impact load transmitted from the fan blade (20) to the outer bearing ring (13) exceeds a threshold value, the first mechanically weak part (141) and / or the second mechanically weak part (142) of the outer bearing ring (13) fails, and the relative movement of the spherical hinge pair squeezes the energy absorption layer (15).

5. An installation method, characterized in that, The fan blade (20) is mounted to the hub (30) by using the fan blade mounting structure (10) according to any one of claims 1-4.

6. An open rotor engine (100), characterized in that, It includes the fan blade mounting structure (10) according to any one of claims 1-4, a fan blade (20), and a hub (30). The fan blade (20) includes a blade shank (40), and the blade shank (40) is mounted to the hub (30) by the fan blade mounting structure (10) so that the fan blade (20) is mounted and connected to the hub (30).

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