Two-plane engine damping device

Abstract

The utility model provides a kind of double plane engine damping device, it is related to power device damping field, the device includes front row damper and rear row damper, front row damper is detachably fixed on the main installation case of engine, near the centroid position of engine, for bearing the thrust and torque load of engine, with the front row damper of engine lower part fixedness vertical arrangement, it is convenient to directly hoist engine installation;Rear row damper is fixed on the auxiliary installation case of engine, release itself in thrust direction degree of freedom on structure, for balancing the deformation posture of engine and significantly inhibiting relative deformation under pitch posture.Double plane engine damping device can effectively cope with the axial thrust, pitch torque and other multidimensional complex vibration of engine, significantly improve overall damping efficiency and system operation stability.The vertical arrangement of part front row damper, realizes that engine can be completed with airplane hanger by direct hoisting and docking installation, simplifies installation process.

Description

Technical Field

[0001] This utility model relates to the field of aviation vibration reduction technology, and in particular to a dual-plane engine vibration reduction device. Background Technology

[0002] Aero engines are one of the main sources of vibration for various aircraft pylons. Engine vibrations are transmitted to the aircraft fuselage through vibration dampers, causing cabin noise and airframe vibrations, leading to damage to some airborne equipment and affecting flight safety. For turboprop engines, the vibration primarily originates from propeller rotation (first-order excitation frequency approximately 70Hz). This frequency easily couples with the natural frequencies of the engine nacelle and fuselage, leading to structural resonance risks. Furthermore, during engine start-up / shutdown, the large rate of change in engine speed causes instantaneous impact vibrations in the gearbox and transmission system, severely affecting engine lifespan and flight comfort.

[0003] Therefore, existing technologies require the installation of vibration damping devices to reduce the transmission of engine vibration to the aircraft fuselage.

[0004] The applicant has discovered at least the following technical problems with the existing technology: Existing vibration damping devices only have a certain damping effect in a single direction; their damping capacity is relatively limited for complex multi-directional vibrations. Existing vibration damping devices can only dissipate vibration energy through a single path; for some high-frequency or large-amplitude vibrations, they may not be effectively absorbed, resulting in poor damping performance. Utility Model Content

[0005] The purpose of this invention is to provide a dual-plane engine vibration damping device to solve the technical problem that existing vibration damping devices are unable to effectively dampen complex multi-directional vibrations and have poor damping effects. The various technical effects of the preferred solutions among the many technical solutions provided by this invention are detailed below.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The dual-plane engine vibration damping device provided by this utility model includes a front row of vibration dampers and a rear row of vibration dampers for fixing the engine and the aircraft pylon, wherein: The front shock absorbers are used to bear the thrust and torque loads of the engine. All front shock absorbers are detachably fixed to the main mounting housing of the engine and located near the center of gravity of the engine. The front shock absorbers fixed to the lower part of the engine are vertically arranged to facilitate direct hoisting of the engine for installation. The rear shock absorber is fixed to the auxiliary mounting box of the engine, structurally releasing its own degree of freedom in the thrust direction, which is used to balance the deformation attitude of the engine and significantly suppress the relative deformation in the pitch attitude.

[0007] Preferably, all the front shock absorbers are arranged at intervals on the mounting section of the engine and are inclined relative to the vertical line compared to the front shock absorbers fixed to the upper part of the engine. The number of rear shock absorbers is one or two. When the number of rear shock absorbers is two, the rear shock absorbers are arranged symmetrically about the axis of the engine, either vertically or horizontally.

[0008] Preferably, the front shock absorber includes a bracket and a first rubber assembly, wherein: The bracket is used for detachable and fixed connection with the engine. The first rubber assembly is fixed to the front and / or rear side of the bracket. A front locking member passes through the bracket and all the first rubber assemblies to fix the front shock absorber and the aircraft rack. The center of the front shock absorber is set off-center relative to the center of the front locking member to resist the counter-torque generated by the propeller rotation on the engine.

[0009] Preferably, the front shock absorber further includes a limiting sleeve, which passes through the first rubber assembly and the bracket. The bracket is provided with a limiting groove, and the limiting sleeve extends into the limiting groove. The front locking member passes through the limiting sleeve to fix the front shock absorber and the aircraft rack in place. The limiting sleeve cooperates with the inner wall of the limiting groove to limit the displacement of the front shock absorber.

[0010] Preferably, the first rubber assembly includes a front support plate, an elastic rubber plate, and a rear cover plate, wherein: The front support plate and the rear cover plate clamp and fix the elastic rubber plate, and the three are vulcanized integral molding structures.

[0011] Preferably, the bracket includes an integrally formed base and a support plate, wherein: The base is perpendicular to the support plate, and the base is provided with holes for fixed connection with the engine; The support plate and / or the base are provided with weight reduction holes. The first rubber assembly is fixed to the front and rear sides of the support plate. A first gasket is clamped and fixed between the first rubber assembly and the support plate. A second gasket is installed at the bottom of the base. A reinforcing rib is provided between the support plate and the base.

[0012] Preferably, one of the bracket and the first rubber component is provided with a positioning hole, and the other is provided with a positioning post. There are at least two positioning holes of different sizes, and at least two positioning posts of different sizes. The positioning holes and the corresponding positioning posts are inserted and matched to ensure that the first rubber component and the bracket are accurately installed. The bottom of the bracket is provided with a protruding anti-shear positioning groove for positioning with the engine.

[0013] Preferably, the rear shock absorber includes a support frame and a second rubber assembly, wherein: The support frame has a first connecting end and a second connecting end, and a rear locking member passes through the first connecting end and the support frame, thereby detachably and fixedly connecting the rear shock absorber to the aircraft rack. The number of the second connection ends is one or more, for detachable and fixed connection with the engine.

[0014] Preferably, the support frame includes a tripod and an end frame, wherein: The second connecting end is located at the two bottom ends of the tripod, and the first connecting end is located at the top of the end frame. The end frame is provided with spaced fixing holes and mounting slots. The rear locking member passes through the fixing holes to fix or rotate the end frame to the aircraft rack, thereby allowing the rear shock absorber to structurally release its degree of freedom in the thrust direction.

[0015] The other end of the tripod extends into the mounting groove and is rotatably connected to the end frame. The second rubber assembly is located on one side or opposite sides of the mounting groove. A fixing member passes through the mounting groove and the second rubber assembly fixes the second rubber assembly at the mounting groove.

[0016] Preferably, the fastener is provided with a T-shaped limiting tube, the body of the T-shaped limiting tube passes through the second rubber assembly, and the end of the T-shaped limiting tube abuts against the outside of the second rubber assembly; The support frame is provided with a weight-reducing hollow area.

[0017] The dual-plane engine vibration damping device provided by this utility model has the following advantages compared with the prior art: Front and rear vibration dampers are installed at the front and rear ends of the engine, respectively, and are given different stiffness characteristics. The front vibration dampers bear the thrust and torque loads of the engine, while the rear vibration dampers are fixed to the engine's auxiliary mounting casing. Structurally, this releases the device's degree of freedom in the thrust direction, balancing the engine's deformation attitude and significantly suppressing relative deformation under pitch attitude. This achieves functional division and synergy, effectively and simultaneously addressing multi-dimensional complex vibrations such as axial thrust and pitch moment, significantly improving overall vibration damping efficiency and system operational stability. Furthermore, the vertical arrangement of some of the front vibration dampers allows for direct hoisting of the engine to the aircraft pylon, greatly simplifying the installation process, shortening assembly and maintenance time, ensuring the device's operational stability, installation accuracy, and structural integrity in harsh aviation environments, and improving overall reliability and safety. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the overall structure of a dual-plane engine vibration damping device; Figure 2 This is a schematic diagram assuming all front shock absorbers are arranged around the engine's axis; Figure 3 This is a schematic diagram of the arrangement structure of the front shock absorbers in this embodiment; Figure 4 This is a schematic diagram of the overall structure of the front shock absorber; Figure 5 This is an exploded view of the front shock absorber. Figure 6 This is a schematic diagram of the arrangement of the front shock absorbers and front locking components; Figure 7 This is a cross-sectional structural diagram of the front shock absorber; Figure 8 This is a schematic diagram of the fit between the limiting sleeve and the limiting groove; Figure 9 This is a structural diagram of the bracket in the front shock absorber; Figure 10 This is a structural diagram of the rear cover plate; Figure 11 This is a structural diagram of the rear shock absorber; Figure 12 This is a cross-sectional structural diagram of the rear shock absorber; Figure 13 This is a schematic diagram of the tripod structure; Figure 14 This is a structural schematic diagram of the end frame; Figure 15 It is a curve showing the relationship between transmissivity and frequency.

[0020] In the diagram: 100. Front shock absorber; 1. Bracket; 10. Reinforcing rib; 11. Base; 111. Hole; 12. Support plate; 121. Positioning post; 13. Weight reduction hole; 14. Shear positioning post groove; 2. First rubber assembly; 21. Front support plate; 22. Elastic rubber plate; 23. Rear cover plate; 231. Positioning hole; 24. Limiting groove; 3. Front locking component; 4. Limiting sleeve; 5. First gasket; 6. Second gasket; 200. Rear shock absorber; 7. Support frame; 701. First connecting end; 702. Second connecting end; 71. Triangular frame; 72. End frame; 721. Fixing hole; 722. Mounting groove; 73. Weight reduction hollow area; 8. Second rubber assembly; 91. Rear locking component; 92. Fixing component; 93. T-shaped limiting sleeve; 94. Bearing. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0022] In the description of this utility model, it should be understood that the terms "center," "length," "width," "height," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and "side," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0023] This utility model provides a dual-plane engine vibration damping device for connecting an engine to an aircraft pylon, specifically, a dedicated load-bearing structure connected to the aircraft pylon, such as aircraft pylon 300. In one embodiment of this application, the device employs a dual-plane layout to achieve decoupling and isolation of complex engine loads.

[0024] The following is combined Figures 1-15 The technical solution provided by this utility model will be described in more detail.

[0025] like Figures 1-14As shown, the dual-plane engine vibration damping device provided by this utility model includes a front row of vibration dampers 100 and a rear row of vibration dampers 200 for fixing the engine and the aircraft pylon 300. The front row of vibration dampers 100 is used to bear the thrust and torque load of the engine. All front row of vibration dampers 100 are detachably fixed to the main mounting housing of the engine, specifically located at the front end of the engine and close to the center of gravity of the engine. They are vertically arranged with the front row of vibration dampers 100 fixed to the lower part of the engine, so as to facilitate the direct hoisting of the engine. The rear row of vibration dampers 200 is fixed to the auxiliary mounting housing of the engine, specifically located at the rear end of the engine. Structurally, it releases its own degree of freedom in the thrust direction, and is used to balance the deformation attitude of the engine and significantly suppress the relative deformation under pitch attitude.

[0026] See Figure 1 As shown, the front shock absorber 100 is positioned near the engine's center of gravity, which helps to effectively isolate vibrations and reduce the additional torque generated by vibrations. As the main load-bearing structure, the front shock absorber 100 withstands the axial thrust generated by the engine during operation. Figure 1 As shown, the front shock absorber 100 mainly bears the force (direction of engine thrust) and torque load of the engine along the X-axis.

[0027] See Figure 1 As shown, the rear shock absorber 200 is positioned away from the engine's center of gravity, typically at the rear of the engine. The rear shock absorber assembly primarily provides restoring torque, structurally releasing its own degree of freedom in the thrust direction. It is used to balance the engine's deformation posture and significantly suppress relative deformation under pitch posture, suppressing the pitch moment generated by factors such as thrust changes and aerodynamic disturbances, thereby maintaining engine attitude stability. See also... Figure 1 As shown, the rear shock absorber 200 mainly reduces vibration in the Y-axis and Z-axis directions.

[0028] Through this axial dual-plane layout and functional stiffness configuration, the front damper 100 and the rear damper 200 work in synergy: the former mainly bears the thrust, isolates high-frequency vibrations near the center of mass, and also resists torque; the latter mainly controls attitude and suppresses pitch. Understandably, compared to traditional single-plane damping systems, this structure helps to more comprehensively cope with the complex, multi-dimensional, coupled loads unique to turboprop engines, and the dual-plane damping device can more effectively reduce the impact of engine vibration on surrounding components.

[0029] As an alternative implementation, see [link to implementation details]. Figure 1 and Figure 3As shown, all front shock absorbers 100 are spaced apart on the engine mounting section and are inclined relative to the vertical line compared to the front shock absorbers 100 fixed to the upper part of the engine; the number of rear shock absorbers 200 is one or two. When the number of rear shock absorbers 200 is two, the rear shock absorbers 200 are arranged symmetrically about the engine axis, either vertically or horizontally.

[0030] See Figure 3 As shown in the figure, this illustrates the mounting method of the front shock absorber 100. As an optional implementation, the number of front shock absorbers 100 can be multiple (e.g., 3 to 4), see [link to relevant documentation]. Figure 3 As shown, the front shock absorber 100, which is fixed to the lower half of the engine, is vertically installed. When installing the engine and the aircraft pylon, the engine can be lifted directly from the bottom up, which is convenient for installation and the aircraft pylon structure is simple.

[0031] See Figure 2 As shown, assuming the front shock absorber 100 is set around the engine axis, that is, the front shock absorber 100 is set at an angle relative to the vertical line. During installation, since the two lower points are installed at an angle, the engine cannot be lifted directly. It is necessary to install the upper part of the aircraft rack first. After the engine is lifted, the lower part of the aircraft rack is installed with the upper part of the aircraft rack before fixing the front shock absorber 100. The structure is complex and the on-site installation is very cumbersome.

[0032] The layout of the front shock absorber 100 in this embodiment helps to simplify the installation process, reduce the need for complex alignment and multi-axial attitude adjustment, thereby shortening the assembly time and improving maintenance convenience.

[0033] Specifically, this dual-plane engine vibration damping device requires precise distribution of three-dimensional stiffness through geometric design. For example, the front damper can increase the x-axis stiffness by increasing the rubber bearing area, while the rear damper can optimize the y and z-axis flexibility through shear deformation design.

[0034] The following provides a specific implementation of the front shock absorber 100: See [link] Figures 4-7 As shown, the front shock absorber 100 includes a bracket 1 and a first rubber assembly 2, wherein: the bracket 1 is used for detachable fixed connection with the engine, the first rubber assembly 2 is fixed to the front and / or rear side of the bracket 1, and a front locking member 3 passes through the bracket 1 and all the first rubber assemblies 2 for fixed connection of the front shock absorber 100 and the aircraft rack.

[0035] Furthermore, to address the counter-torque unique to turboprop engines generated by propeller rotation, an eccentric design can be employed in the front shock absorber 100 in this embodiment. See also Figure 6The center of the front shock absorber 100 is offset from the center of the front locking member 3 to resist the counter-torque generated by the propeller rotation on the engine.

[0036] like Figure 6 As shown, the purpose of the above structure is to resist the counter-torque generated by the propeller's torsion on the engine. This eccentric design can be understood as follows: the elastic center C1 of the first rubber component 2 (i.e., the center of symmetry of its geometry and elastic properties under no-stress conditions) has a predetermined offset distance relative to the center C2 of the locking element connecting it to the aircraft pylon (typically the center of the axis of the front locking element 3, such as a long bolt, passing through the entire front shock absorber 100). When the propeller rotates, the engine generates a counter-torque, and the entire front shock absorber 100 will rotate slightly around the center C2 of the front locking element 3. Due to the offset of the elastic center C1, the first rubber component 2 will generate a restoring torque to resist this rotation, thereby effectively absorbing and balancing the counter-torque and preventing it from being transmitted to the airframe structure. After the deflection, the center of the front shock absorber 100 coincides with the center of the front locking element 3. This structure integrates anti-torsion function into the shock absorber itself, resulting in a compact structure.

[0037] The bracket 1 can be made of high-strength alloy materials (such as titanium alloy or high-strength steel), and its shape can be optimized according to the installation position, for example, it can be designed as a T-shape.

[0038] As an alternative implementation, see [link to implementation details]. Figure 4 , Figure 5 and Figure 7 , Figure 9 As shown, the bracket 1 includes an integrally formed base 11 and a support plate 12, wherein: the base 11 is perpendicularly arranged to the support plate 12, and the base 11 is provided with holes 111 for fixed connection with the engine; the support plate 12 and / or the base 11 are provided with weight reduction holes 13, the first rubber assembly 2 is fixed to the front and rear sides of the support plate 12, and the support plate 12 and the base 11 are provided with reinforcing ribs 10.

[0039] Considering the high-temperature environment during engine operation, embodiments of this application also include a thermal protection structure. For example... Figure 5 As shown, a first gasket 5 is clamped and fixed between the first rubber assembly 2 and the support plate 12, and a second gasket 6 is installed at the bottom of the base 11. The first gasket 5 and the second gasket 6 can be heat insulation pads, which are typically made of materials with extremely low thermal conductivity, such as mica sheets or ceramic fiber composite materials. In this embodiment, mica material with a thermal conductivity of less than 0.1 W / m·Kelvin can be selected. By setting a heat insulation pad with a thickness not exceeding 2 mm after compression, the surface temperature near the engine casing, which may reach up to 400°C, can be effectively isolated, ensuring that the operating temperature of the first rubber assembly 2 remains within its permissible range (e.g., below 130°C), thereby guaranteeing its performance and lifespan.

[0040] For example, the base 11 can be fixed to the engine by passing multiple high-strength bolts (such as 4 bolts) through the hole 111.

[0041] To ensure safety in extreme conditions, a through-type limiting structure is installed inside the shock absorber. As an optional implementation, see [link to alternative implementation]. Figure 8 As shown, the front shock absorber 100 also includes a limiting sleeve 4, which passes through the first rubber assembly 2 and the bracket 1. The bracket 1 (specifically the support plate 12) is provided with a limiting groove 24. The limiting sleeve 4 extends into the limiting groove 24. The front locking member 3 passes through the limiting sleeve 4 to fix the front shock absorber 100 and the aircraft rack. The limiting sleeve 4 cooperates with the inner wall of the limiting groove 24 to limit the displacement of the front shock absorber 100.

[0042] See Figure 8 As shown, the limiting sleeve 4 passes through the center hole of the support plate 12 and the first rubber assembly 2, and the front locking member 3 passes through the limiting sleeve 4 and locks with the aircraft pylon. Under normal operation, the front shock absorber 100 undergoes elastic deformation, and the limiting sleeve 4 does not contact the limiting groove 24. However, in the event of an accident, the displacement of the engine will be restricted by the limiting sleeve 4 and the limiting groove 24, and the bracket 1 will directly and rigidly contact the limiting sleeve 4 or the front locking member 3, thereby maintaining the mechanical connection between the engine and the aircraft pylon, preventing excessive engine movement, and providing ultimate fail-safe protection.

[0043] The structure of this embodiment has a failure prevention function: the high-strength front locking member 3 passes through the first rubber assembly 2 and the limiting sleeve 4 to connect with the aircraft pylon. This ensures that the engine will not detach from the aircraft pylon. Under the pre-tightening force of the front locking member 3, the two front support plates 21 + limiting sleeve 4 + bracket 1 are rigidly fitted together, ensuring an effective connection between the engine and the aircraft. Even if the first rubber assembly 2 is completely damaged or burned, it can still ensure that the engine will not detach from the aircraft pylon and no safety issues will occur.

[0044] As an alternative implementation, see [link to implementation details]. Figure 5 and Figure 7 As shown, the first rubber assembly 2 includes a front support plate 21, an elastic rubber plate 22, and a rear cover plate 23, wherein the front support plate 21 and the rear cover plate 23 clamp and fix the elastic rubber plate 22, and the three are vulcanized integral molding structures.

[0045] The front support plate 21 can be made of metal and is mainly used to bear various loads acting on the front shock absorber 100, especially the yaw load; the elastic rubber plate 22 is used to absorb the vibration generated by the engine and its propeller and prevent the transmission of vibration between the fuselage and the engine; the rear cover plate 23 and the elastic rubber plate 22 together serve as a limit.

[0046] The first rubber assembly 2 is used to achieve vibration damping. In one embodiment of this application, the front support plate 21, the elastic rubber plate 22, and the rear cover plate 23 are integrally formed by a high-temperature and high-pressure vulcanization process to ensure high bonding strength and reliability between the rubber and the metal parts. It should be noted that the rubber material can be selected from silicone rubber or fluororubber, which have high damping, high temperature resistance (e.g., can work in environments above 130°C for a long time), and excellent aging resistance.

[0047] Adding at least one layer of spacer inside the elastic rubber sheet 22 between the front support plate 21 and the rear cover plate 23 can effectively improve the load-bearing capacity and extend the service life of the first rubber assembly 2.

[0048] The geometry of the first rubber component 2 is also specially designed, for example, by using a rectangular cross-section. The purpose is to provide a larger force-bearing area in a limited radial space compared to a circular cross-section, thereby increasing the axial and radial area of ​​the first rubber component 2, increasing the compressive stiffness and shear stiffness, and thus achieving the required stiffness characteristics in different directions.

[0049] To improve assembly accuracy and prevent incorrect installation, a mis-assembly prevention structure can be provided between the first rubber assembly 2 of the front shock absorber 100 and the bracket 1. Alternatively, one of the bracket 1 and the first rubber assembly 2 may have a positioning hole 231, and the other may have a positioning post 121. (See [reference]). Figure 9 and Figure 10 As shown, in this embodiment, the bracket 1 is provided with positioning posts 121, and the rear cover plate 23 is provided with positioning holes 231. There are at least two positioning holes 231 of different sizes, and there are at least two positioning posts 121 of different sizes. The positioning holes 231 are inserted and matched with the corresponding size positioning posts 121 to ensure that the first rubber component 2 and the bracket 1 are accurately installed.

[0050] See Figure 9 and Figure 10 As shown, since the size and shape combination of the positioning post 121 and the positioning hole 231 is unique, the bracket 1 and the first rubber component 2 can only be assembled in the preset correct relative position and direction, thereby effectively avoiding misassembly and ensuring the correctness of the eccentric design and the realization of overall performance.

[0051] The main load-bearing components have undergone ultimate strength testing, and the safety factor is greater than or equal to 2.

[0052] The vibration damping device in this embodiment also has a large load-bearing capacity: see [link / reference] Figure 9The front shock absorber bracket 1 (T-type) is the main load-bearing part. There are 4 bolts at the connection between the bracket 1 and the engine. It is easy to cause danger if the tangential load is supported by only 4 bolts. Therefore, the bottom of the bracket 1 is provided with a protruding anti-shear positioning column 121 groove for positioning with the engine.

[0053] The above structure can greatly improve shear resistance. The reinforcing ribs 10 at the bottom and vertical part of the support frame 7 are also designed to improve shear resistance.

[0054] See Figure 1 and Figure 11 As shown, the main function of the rear shock absorber 200 is to structurally release its own degree of freedom in the thrust direction, balance the deformation posture of the engine, and significantly suppress the relative deformation under pitch posture.

[0055] In this embodiment, see Figures 11-14 As shown, the rear shock absorber 200 includes a support frame 7 and a second rubber assembly 8. The support frame 7 has a first connecting end 701 and a second connecting end 702. A rear locking member 91 passes through the first connecting end 701 to detachably and securely connect the rear shock absorber 200 to the aircraft pylon. The number of second connecting ends 702 is one or more, used for detachably and securely connecting to the engine mounting section. The structure of the second rubber assembly 8 may include rubber blocks clamped between two plates, etc., and is not limited here.

[0056] See Figures 11-13 As shown, in this embodiment, there are two second connecting ends 702. The support frame 7 is generally A-shaped. The three ends of the A-shape are a first connecting end 701 and two second connecting ends 702. The second connecting ends 702 are located at the bottom of the support frame 7. Multiple holes for connecting to the engine are provided at the bottom end. The middle is a weight-reducing hollow area 73. The second connecting ends 702 are firmly connected to the engine mounting section.

[0057] When the engine pitches upwards or downwards, the rear shock absorber 200 is subjected to a vertical force, causing the second rubber assembly 8 to undergo shear or compression deformation, generating a restoring force. Because its mounting position is far from the center of gravity, this restoring force forms an effective restoring torque, thereby suppressing pitch movement.

[0058] As an alternative implementation, see [link to implementation details]. Figures 11-14As shown, the support frame 7 includes a tripod 71 and an end frame 72, wherein: the second connecting end 702 is located at the two bottom ends of the tripod 71, the first connecting end 701 is located at the top of the end frame 72, the end frame 72 is provided with spaced fixing holes 721 and mounting grooves 722, the rear locking member 91 passes through the fixing holes 721 to fix or rotate the end frame 72 to the aircraft rack; the other end of the tripod extends into the mounting groove 722 and rotates to connect with the end frame 72, the second rubber assembly 8 is located on one side or opposite sides of the mounting groove 722, and a fixing member 92 (which can be a high-strength bolt) passes through the mounting groove 722 and the second rubber assembly 8 to fix the second rubber assembly 8 to the outside of the mounting groove 722 on both sides.

[0059] The other end of the tripod 71 extends into the mounting groove 722 and is rotatably connected to the end frame 72 via a bearing 94. In this embodiment, the bearing 94 at the upper end of the rear shock absorber 200 support frame 7 is connected to the aircraft rack, and the tripod 71 is connected to the engine. The middle part is a flexible structure (the flexible structure is: the structure of the second rubber component 8, and the tripod 71 is rotatably connected to the end frame 72), which can achieve the function of auxiliary vibration reduction while releasing the degree of freedom.

[0060] At the same time, considering that the engine will experience axial elongation or shortening due to thermal expansion and contraction during operation, such as Figure 12 As shown, a dimensional clearance is reserved at the mating point between the mounting slot 722 of the end bracket 72 and the tripod 71 to form a thermal expansion clearance. This clearance allows for slight axial movement of the engine to compensate for thermal deformation, avoiding excessive thermal stress inside the damper, thereby improving the reliability of the entire device under wide temperature range operation.

[0061] Similar to the front shock absorber 100, see [link / reference]. Figure 12 The rear shock absorber 200 has a T-shaped limiting cylinder 93 on its fixing component 92. The cylinder of the T-shaped limiting cylinder 93 passes through the second rubber component 8, and the end of the T-shaped limiting cylinder 93 abuts against the outside of the second rubber component 8. The support frame 7 is provided with a weight-reducing hollow area 73.

[0062] The rear shock absorber 200 is also equipped with a T-shaped limit sleeve 4 as a fail-safe mechanism. It will not separate from the support frame 7 even if the second rubber assembly 8 is damaged (consistent with the fail-safe design principle mentioned above).

[0063] See Figure 1 and Figure 3As shown, the installation method may include the following steps: The engine, pre-installed with the vibration damping device of this embodiment, is lifted as a whole to a predetermined installation position below the aircraft pylon using ground hoisting equipment. The engine is then linearly lifted in a single vertical direction. During this process, the mounting interface of the front shock absorber 100 at the bottom of the engine is aligned with the corresponding load-bearing structure on the aircraft pylon and inserted into it to complete preliminary docking and positioning. The remaining shock absorbers are then fixed, for example, by using the front locking member 3 to completely and securely connect all the front shock absorbers 100 to the aircraft pylon. The rear shock absorbers 200 are connected and fixed, and after tightening and checking all connection points, the entire engine installation process is completed. Accordingly, by using the above method, the engine installation process can be simplified to primarily unidirectional hoisting and docking, which helps reduce the need for complex tooling and multi-axial precise alignment, thereby improving assembly efficiency.

[0064] This embodiment also includes a vibration reduction efficiency analysis: The analysis of the overall vibration reduction efficiency requires the following conditions to be clarified: (1) Excitation frequency. In combination with the working characteristics of the engine, the vibration load is mainly caused by the imbalance of the rotor system, including the rotation of the high-pressure rotor, low-pressure rotor and propeller blades of the engine.

[0065] Based on the project background, the engine excitation frequency mainly includes the frequency of 2000 r / min; (2) Calculate the natural frequency of the selected vibration damper: The natural frequency of the vibration damper depends on its design and material properties, and the modal analysis results of the natural frequency of the whole machine are obtained.

[0066] (3) Frequency ratio (λ): The frequency ratio λ is the ratio of the equipment interference frequency to the vibration damper's natural frequency, i.e., z=f / f0.

[0067] (4) Calculation of force transmissibility (TA): Force transmissibility TA describes the effectiveness of the vibration damper in reducing vibration transmission. According to the vibration damping principle, the formula for calculating force transmissibility may vary depending on the type of vibration damper.

[0068] (5) Calculate the vibration reduction efficiency: The vibration reduction efficiency can be calculated by subtracting the force transmission rate TA from 1, that is, vibration reduction efficiency = 1 - TA. This formula gives the percentage effect of the vibration damper in reducing vibration transmission.

[0069] Damping ratio and transfer function: The vibration reduction effect of a vibration damping system mainly considers the isolation of total vibration energy at the propeller's primary passing frequency and across the entire frequency domain. Vibration transmissibility is determined only by the transmissibility of two modes: the highest mode of force and torque. According to the modal transmissibility formula, the effectiveness of an engine vibration damping system is often measured by transmissibility, which is defined as:

[0070] Where FT represents the acceleration value at the response point, F0 is the acceleration value at the input point, ζ is the damping ratio ζ=c / cc, the damping coefficient is c, the critical damping is cc, and λ is the frequency ratio (i.e., the excitation force frequency or the natural frequency of the engine and propeller / the natural frequency of the system or the natural frequency of the damper).

[0071] The damping ratio is an inherent property of damping materials. The damping ratio (ζ) is an important concept in structural dynamics, primarily used to describe the normalized damping magnitude of a structure. It is the ratio of the damping coefficient to the critical damping coefficient, dimensionless, and represents the decay form of the structure's vibration after excitation. The magnitude of the damping ratio determines the vibration characteristics of the structure and has a significant impact on its stability and reliability. The magnitude of the damping ratio is related to various factors such as the structure's materials, manufacturing process, and surrounding medium. The selection of the damping ratio is crucial to the stability of the vibration system. By choosing an appropriate damping ratio, the vibration amplitude can be effectively reduced, improving the system's stability and reliability.

[0072] According to technical requirements, the shock absorber should have appropriate damping to avoid being in the resonance zone as much as possible, so that the response of the engine during start-up and shutdown through transient resonance is not too large. Based on past experience data, the resonance amplification factor of the engine vibration damping system should not be greater than 5.

[0073] Damping ratio (ζ) and resonance amplification factor are both important parameters in structural dynamics describing the vibration characteristics of a system, but they each have different meanings and effects. Damping ratio is a dimensionless parameter that represents the decay form of a structure's vibration after excitation. It is defined as the ratio of the damping coefficient to the critical damping coefficient, used to express the magnitude of structural damping, and is one of the dynamic characteristics of a structure. See also... Figure 15 As shown, Figure 15 It is a curve showing the relationship between transmissivity and frequency.

[0074] The damping ratio determines the decay rate and vibration mode of a system's vibration, significantly impacting the stability and reliability of the structure. The resonance amplification factor describes the degree to which the vibration amplitude is amplified at the resonant frequency. When a system is subjected to an external excitation close to its natural frequency, resonance occurs, significantly increasing the vibration amplitude. The resonance amplification factor quantifies this amplitude increase. Based on material properties, the damping ratio of damping rubber materials is... ; Based on the engine's main excitation frequency, the vibration reduction effect of the vibration reduction system at the main operating frequency is calculated.

[0075] Table of frequency doubling vibration reduction efficiency (%)

[0076] Calculation results: Based on vibration transmissibility calculations, the vibration damper demonstrates significant damping efficiency at both the first and second harmonic frequencies, exceeding 96% in both cases, meeting the technical requirements. The overall damping efficiency is above 80%, fulfilling the functional requirements for absorbing and reducing vibrations generated by the engine and its propeller.

[0077] The specific features, structures, or characteristics described in this specification may be combined in any suitable manner in one or more embodiments or examples.

[0078] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0079] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. A dual-plane engine vibration damping device, characterized in that, Includes front and rear shock absorbers for connecting the engine and aircraft pylon, wherein: The front shock absorbers are used to bear the thrust and torque loads of the engine. All front shock absorbers are detachably fixed to the main mounting housing of the engine and located near the center of gravity of the engine. The front shock absorbers fixed to the lower part of the engine are vertically arranged to facilitate direct hoisting of the engine for installation. The rear shock absorber is fixed to the auxiliary mounting box of the engine, structurally releasing its own degree of freedom in the thrust direction, which is used to balance the deformation attitude of the engine and significantly suppress the relative deformation in the pitch attitude.

2. The dual-plane engine vibration damping device according to claim 1, characterized in that, All of the aforementioned front shock absorbers are arranged at intervals on the mounting section of the engine and are inclined relative to the vertical line of the front shock absorbers fixed to the upper part of the engine. The number of rear shock absorbers is one or two. When the number of rear shock absorbers is two, the rear shock absorbers are arranged symmetrically about the axis of the engine, either vertically or horizontally.

3. The dual-plane engine vibration damping device according to claim 1, characterized in that, The front shock absorber includes a bracket and a first rubber assembly, wherein: The bracket is used for detachable and fixed connection with the engine. The first rubber assembly is fixed to the front and / or rear side of the bracket. A front locking member passes through the bracket and all the first rubber assemblies to fix the front shock absorber and the aircraft rack. The center of the front shock absorber is set off-center relative to the center of the front locking member to resist the counter-torque generated by the propeller rotation on the engine.

4. The dual-plane engine vibration damping device according to claim 3, characterized in that, The front shock absorber also includes a limiting sleeve, which passes through the first rubber assembly and the bracket. The bracket is provided with a limiting groove, and the limiting sleeve extends into the limiting groove. The front locking member passes through the limiting sleeve to fix the front shock absorber and the aircraft rack in place. The limiting sleeve cooperates with the inner wall of the limiting groove to limit the displacement of the front shock absorber.

5. The dual-plane engine vibration damping device according to claim 3, characterized in that, The first rubber assembly includes a front support plate, an elastic rubber plate, and a rear cover plate, wherein: The front support plate and the rear cover plate clamp and fix the elastic rubber plate, and the three are vulcanized integral molding structures.

6. The dual-plane engine vibration damping device according to claim 3, characterized in that, The bracket includes an integrally formed base and a support plate, wherein: The base is perpendicular to the support plate, and the base is provided with holes for fixed connection with the engine; The support plate and / or the base are provided with weight reduction holes. The first rubber assembly is fixed to the front and rear sides of the support plate. A first gasket is clamped and fixed between the first rubber assembly and the support plate. A second gasket is installed at the bottom of the base. A reinforcing rib is provided between the support plate and the base.

7. The dual-plane engine vibration damping device according to claim 3, characterized in that, Of the bracket and the first rubber component, one is provided with a positioning hole and the other is provided with a positioning post. There are at least two positioning holes of different sizes and at least two positioning posts of different sizes. The positioning holes and the corresponding positioning posts are inserted and matched to ensure that the first rubber component and the bracket are accurately installed. The bottom of the bracket is provided with a protruding shear positioning post for positioning with the engine.

8. The dual-plane engine vibration damping device according to claim 1, characterized in that, The rear shock absorber includes a support frame and a second rubber assembly, wherein: The support frame has a first connecting end and a second connecting end, and a rear locking member passes through the first connecting end and the support frame, thereby detachably and fixedly connecting the rear shock absorber to the aircraft rack. The number of the second connection ends is one or more, for detachable and fixed connection with the engine.

9. The dual-plane engine vibration damping device according to claim 8, characterized in that, The support frame includes a tripod and end frames, wherein: The second connecting end is located at the two bottom ends of the tripod, and the first connecting end is located at the top of the end frame. The end frame is provided with spaced fixing holes and mounting slots. The rear locking member passes through the fixing holes to fix or rotate the end frame to the aircraft rack, thereby allowing the rear shock absorber to structurally release its degree of freedom in the thrust direction. The other end of the tripod extends into the mounting groove and is rotatably connected to the end frame. The second rubber assembly is located on one side or opposite sides of the mounting groove. A fixing member passes through the mounting groove and the second rubber assembly fixes the second rubber assembly at the mounting groove.

10. The dual-plane engine vibration damping device according to claim 9, characterized in that, The fastener is fitted with a T-shaped limiting tube, the body of which passes through the second rubber assembly, and the end of which abuts against the outside of the second rubber assembly. The support frame is provided with a weight-reducing hollow area.

Images