Three-degree-of-freedom adjustable dynamic vibration absorber for aircraft engine pylon

Abstract

This invention discloses a three-degree-of-freedom adjustable dynamic vibration absorber for an aircraft engine pylon, comprising: an engine pylon for mounting an aircraft engine; a dynamic vibration absorber bracket fixedly installed in the middle of the engine pylon, the dynamic vibration absorber bracket having a Cartesian coordinate structure; and six spring dampers movably disposed in the middle of the dynamic vibration absorber bracket, the spring dampers including a first universal joint fixedly disposed inside the dynamic vibration absorber bracket. This invention achieves passive vibration control with a small mass and wide bandwidth by combining linear and nonlinear dynamic vibration absorbers during the movement of the oscillator mass block, where two springs along the axial direction undergo linear changes while the remaining four springs undergo nonlinear changes. It provides vibration suppression capability with three degrees of freedom, thus adapting to complex multi-degree-of-freedom vibration suppression conditions under different flight attitudes and directions of the aircraft.

Description

Technical Field

[0001] This invention relates to the field of dynamic vibration damping device technology, specifically a three-degree-of-freedom adjustable dynamic vibration damper for an aircraft engine pylon. Background Technology

[0002] Modern large passenger aircraft engines are connected to the wings via a pylon structure, which transmits the thrust generated by the engine to the fuselage. Due to the complexity of the engine structure, the high precision of component manufacturing and assembly, the harsh working environment, and the enormous operating load, engine vibration is inevitable during operation. This engine vibration can cause fatigue damage to aircraft components, shorten their lifespan, severely impact the passenger experience, and even seriously jeopardize safe flight. A three-degree-of-freedom adjustable dynamic vibration absorber for aircraft engine pylons features simple structure, convenient installation and maintenance, fast response, and high reliability. Installed inside the engine pylon structure, when the vibrator mass moves, two springs along the axial direction undergo linear changes, while the remaining four springs exhibit nonlinear changes. This combination of linear and nonlinear dynamic vibration absorbers enables passive vibration control with a small mass and wide bandwidth, providing vibration suppression capability in three degrees of freedom. It offers three vibration suppression modes: translational vibration absorption, rotational vibration absorption, and a combination of translational and rotational vibration absorption. The three-degree-of-freedom dynamic vibration absorber provided by this invention can adapt to complex multi-degree-of-freedom vibration suppression conditions under different flight attitudes and directions, more efficiently absorbing engine vibration and dissipating vibration energy. It has significant development value and broad application prospects in the field of aerospace vibration reduction technology.

[0003] However, in practical use, the existing technology only reduces vibration of the engine pylon in the circumferential direction. Due to the inability of the engine pylon to move in multiple directions, the vibration reduction direction is singular and cannot adapt to the suppression of complex vibrations caused by the multi-degree-of-freedom of different flight attitudes and directions of the aircraft. Summary of the Invention

[0004] The purpose of this invention is to provide a three-degree-of-freedom adjustable dynamic vibration absorber for an aircraft engine pylon, in order to solve the problem that simply reducing vibration of the engine pylon from the circumferential position is limited by the inability of the engine pylon to move in multiple directions. This results in a single vibration reduction direction, which cannot adapt to the suppression of complex vibrations caused by multiple degrees of freedom in different flight attitudes and flight directions of the aircraft.

[0005] To achieve the above objectives, the present invention provides the following technical solution: including:

[0006] Engine pylons used for mounting aircraft engines;

[0007] A power vibration absorber bracket is fixedly installed in the middle of the engine mount, and the power vibration absorber bracket has a Cartesian space coordinate structure;

[0008] A spring damper is movably installed in the middle of the dynamic vibration absorber bracket. There are six spring dampers. Each spring damper includes a first universal joint fixedly installed inside the dynamic vibration absorber bracket. A circular guide rod is fixedly installed at one end of the first universal joint. A guide tube is movably sleeved on the surface of the circular guide rod so that the circular guide rod can move along the direction of the guide tube. A spring for damping vibration is fixedly installed at one end of the first universal joint and the guide tube corresponding to the position of the circular guide rod. A second universal joint is fixedly installed at the end of the guide tube away from the position of the spring.

[0009] The oscillator mass block is located in the middle of the power vibration absorber bracket. The oscillator mass block includes an oscillator center mounting block. The surface of the oscillator center mounting block is provided with six connecting shafts, which are distributed in a Cartesian coordinate structure. The six first universal joints are respectively fixed to one end of the connecting shafts on the surface of the oscillator center mounting block. When the aircraft engine is vibrated, the oscillator center mounting block moves along the direction of the connecting shafts and drives the circular guide rod and guide tube to move relative to each other, causing the spring to deform. This suppresses the vibration generated by the multi-degree-of-freedom aircraft engine.

[0010] Preferably, the power vibration absorber bracket includes six square plates, and the line connecting the middle of the six square plates forms a Cartesian coordinate system. The four corners of the square plates are fixedly connected to the middle of the engine mount by screws. A square hollow guide rod is fixedly connected to each of the four corners of the square plate at the end corresponding to the origin of the coordinate system. The ends of three adjacent square hollow guide rods are fixedly connected at their corresponding positions.

[0011] Preferably, the end of the first universal joint furthest from the circular guide rod is threadedly connected to a first screw, and the first screw is threadedly connected to one end of the connecting shaft of the oscillator center mounting block. The end of the second universal joint furthest from the guide tube is threadedly connected to a bolt. The end of the bolt furthest from the second universal joint is rotatably connected to the middle of the square plate, and the diameter of the end of the bolt furthest from the second universal joint is larger than the diameter of the end of the bolt at the corresponding second universal joint position, so that the bolt cannot penetrate the square plate from the direction of the corresponding second universal joint position.

[0012] Preferably, a first spring retainer is fixedly connected to one end of the spring corresponding to the position of the first universal joint, and the first spring retainer is tightly fitted to one end of the first universal joint; a second spring retainer is fixedly connected to one end of the spring corresponding to the position of the guide tube, and the second spring retainer is tightly fitted to one end of the guide tube; the end of the circular guide rod corresponding to the position of the first universal joint is threaded, and the circular guide rod is threaded to the inner wall of the first universal joint.

[0013] Preferably, a linear motion damper is movably provided on the inner wall of the guide tube, and the inner wall of the guide tube and the surface of the linear motion damper are in clearance fit. The linear motion damper is movably connected to the surface of the circular guide rod, and the inner wall of the linear motion damper and the surface of the circular guide rod are in transition fit.

[0014] Preferably, a shaft end retaining ring is movably provided on the inner wall of the end of the guide tube away from the linear motion damper. The side walls of the guide tube corresponding to the positions of the linear motion damper and the shaft end retaining ring are respectively threaded with fastening screws, so that the linear motion damper and the shaft end retaining ring are axially fixed to the inner wall of the guide tube. The inner wall of the shaft end retaining ring is threaded with a second screw, and the second screw is threaded with the inner wall of the second universal joint.

[0015] Preferably, the shoulder end of the circular guide rod is located on the inner wall of the guide tube, and the diameter of the shoulder end of the circular guide rod is larger than the inner diameter of the linear motion damper and the shaft end retaining ring, and the smooth end of the circular guide rod is located on the inner wall of the first universal joint.

[0016] Preferably, a bearing is rotatably connected to the surface of the connecting shaft of the oscillator center mounting block. The surface of the connecting shaft of the oscillator center mounting block has a groove, and a bearing retainer is engaged with the inner wall of the groove. The bearing retainer is tightly fitted to one end of the bearing. The bearing is located between the bearing retainer and the shoulder of the connecting shaft of the oscillator center mounting block, so that the bearing is axially fixed to the connecting shaft of the oscillator center mounting block. The outer ring of the bearing is transitionally fitted with a square hollow guide rod, so that the bearing rotates on the surface of the square hollow guide rod. The inner ring of the bearing is transitionally fitted with the surface of the connecting shaft of the oscillator center mounting block. The inner wall of the bearing retainer is clearance-fitted with the inner wall of the groove on the surface of the connecting shaft of the oscillator center mounting block.

[0017] Compared with the prior art, the beneficial effects of the present invention are:

[0018] 1. This invention combines a linear motion damper and springs, featuring a simple structure, convenient installation and maintenance, fast response, and high reliability. When installed inside the engine mount structure, as the vibrator mass moves, two springs along the axial direction exhibit linear changes, while the remaining four springs undergo nonlinear changes. This combination of linear and nonlinear dynamic vibration absorbers enables passive vibration control with a small mass and wide bandwidth, providing vibration suppression capabilities in three degrees of freedom: translational vibration absorption, rotational vibration absorption, and a combination of translational and rotational vibration absorption. Furthermore, the three-degree-of-freedom dynamic vibration absorber provided by this invention can adapt to complex multi-degree-of-freedom vibration suppression conditions under different flight attitudes and directions, more efficiently absorbing engine vibration and dissipating vibration energy. It has significant development value and broad application prospects in the field of aerospace vibration reduction technology. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of a three-degree-of-freedom adjustable dynamic vibration absorber for an aircraft engine pylon according to the present invention.

[0020] Figure 2 This is a partial schematic diagram of the overall structure of a three-degree-of-freedom adjustable dynamic vibration absorber for an aircraft engine pylon according to the present invention. Figure 1 ;

[0021] Figure 3 This is a partial schematic diagram of the overall structure of a three-degree-of-freedom adjustable dynamic vibration absorber for an aircraft engine pylon according to the present invention. Figure 2 ;

[0022] Figure 4 This is a partial schematic diagram of the overall structure of a three-degree-of-freedom adjustable dynamic vibration absorber for an aircraft engine pylon according to the present invention. Figure 3 ;

[0023] Figure 5 This is a schematic diagram of the support structure of a three-degree-of-freedom adjustable dynamic vibration absorber for an aircraft engine pylon according to the present invention.

[0024] Figure 6 This is a schematic diagram of a three-degree-of-freedom adjustable dynamic vibration absorber spring damper structure for an aircraft engine pylon according to the present invention.

[0025] Figure 7 This is a cross-sectional view of a three-degree-of-freedom adjustable dynamic vibration absorber spring damper structure for an aircraft engine pylon according to the present invention.

[0026] Figure 8 This invention relates to a three-degree-of-freedom adjustable dynamic shock absorber and spring damper structure for an aircraft engine pylon. Figure 1 ;

[0027] Figure 9 This invention relates to a three-degree-of-freedom adjustable dynamic shock absorber and spring damper structure for an aircraft engine pylon. Figure 2 ;

[0028] Figure 10 This is a schematic diagram of the oscillator mass block structure of a three-degree-of-freedom adjustable dynamic vibration absorber for an aircraft engine pylon according to the present invention.

[0029] Figure 11 This is an exploded view of the oscillator mass block structure of a three-degree-of-freedom adjustable dynamic vibration absorber for an aircraft engine pylon according to the present invention.

[0030] Figure 12 This is a cross-sectional view of the oscillator mass block structure of a three-degree-of-freedom adjustable dynamic vibration absorber for an aircraft engine pylon according to the present invention.

[0031] Figure 13This is a schematic diagram of the translational vibration absorption and suppression control of a three-degree-of-freedom adjustable dynamic vibration absorber for an aircraft engine pylon according to the present invention.

[0032] Figure 14 This is a schematic diagram of the rotational vibration absorption and suppression control of a three-degree-of-freedom adjustable dynamic vibration absorber for an aircraft engine pylon according to the present invention.

[0033] Figure 15 This is a schematic diagram of the translational and rotational vibration absorption and suppression control of a three-degree-of-freedom adjustable dynamic vibration absorber for an aircraft engine pylon according to the present invention.

[0034] In the picture: 1. Engine hoist;

[0035] 201. Square plate; 202. Square hollow guide rod;

[0036] 301. First screw; 302. First universal joint; 303. First spring retainer; 304. Spring; 305. Second spring retainer; 306. Circular guide rod; 307. Linear motion damper; 308. Guide tube; 309. Shaft end retaining ring; 310. Second screw; 311. Second universal joint; 312. Bolt;

[0037] 401. Oscillator center mounting block; 402. Bearing; 403. Bearing retainer ring. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] Please see Figure 1-15 The present invention provides a technical solution comprising:

[0040] Engine pylon 1 for mounting aircraft engines;

[0041] A power vibration absorber bracket is fixedly installed in the middle of the engine mount 1. The power vibration absorber bracket has a Cartesian space coordinate structure.

[0042] A spring damper is movably installed in the middle of the dynamic vibration absorber bracket. There are six spring dampers. The spring damper includes a first universal joint 302 fixedly installed inside the dynamic vibration absorber bracket. A circular guide rod 306 is fixedly installed at one end of the first universal joint 302. A guide tube 308 is movably sleeved on the surface of the circular guide rod 306 so that the circular guide rod 306 can move along the direction of the guide tube 308. A spring 304 for suppressing vibration is fixedly installed at one end of the first universal joint 302 and the guide tube 308 corresponding to the position of the circular guide rod 306. A second universal joint 311 is fixedly installed at one end of the guide tube 308 away from the position of the spring 304.

[0043] The oscillator mass block, which is located in the middle of the dynamic vibration absorber bracket, includes an oscillator center mounting block 401. The surface of the oscillator center mounting block 401 is provided with six connecting shafts, which are distributed in a Cartesian coordinate structure. The six first universal joints 302 are respectively fixedly installed at one end of the connecting shafts on the surface of the oscillator center mounting block 401. When the aircraft engine is vibrated, the oscillator center mounting block 401 moves along the direction of the connecting shafts and drives the circular guide rod 306 and the guide tube 308 to move relative to each other, causing the spring 304 to deform. This achieves the effect of suppressing the vibration generated by the multi-degree-of-freedom of the aircraft engine.

[0044] The power vibration absorber bracket includes six square plates 201, and the line connecting the six square plates 201 forms a Cartesian coordinate system. The four corners of the square plates 201 are fixedly installed in the middle of the engine mount 1 by screws. Square hollow guide rods 202 are fixedly installed at the four corners of the square plates 201 corresponding to the origin of the coordinate system. The corresponding ends of three adjacent square hollow guide rods 202 are fixedly installed.

[0045] The first universal joint 302 is threaded to a first screw 301 at the end furthest from the circular guide rod 306, and the first screw 301 is threaded to one end of the connecting shaft of the oscillator center mounting block 401. The second universal joint 311 is threaded to a bolt 312 at the end furthest from the guide tube 308. The end of the bolt 312 furthest from the second universal joint 311 is rotatably connected to the middle of the square plate 201, and the diameter of the end of the bolt 312 furthest from the second universal joint 311 is larger than the diameter of the end of the bolt 312 at the corresponding position of the second universal joint 311, so that the bolt 312 cannot penetrate the square plate 201 from the direction of the corresponding position of the second universal joint 311.

[0046] A first spring retainer 303 is fixedly installed at one end of spring 304 corresponding to the position of the first universal joint 302, and the first spring retainer 303 is tightly fitted to one end of the first universal joint 302. A second spring retainer 305 is fixedly installed at one end of spring 304 corresponding to the position of guide tube 308, and the second spring retainer 305 is tightly fitted to one end of guide tube 308. A circular guide rod 306 is threaded at one end corresponding to the position of the first universal joint 302, and the circular guide rod 306 is threaded to the inner wall of the first universal joint 302.

[0047] A linear motion damper 307 is movably provided on the inner wall of the guide tube 308, and the inner wall of the guide tube 308 is clearance-fitted with the surface of the linear motion damper 307. The linear motion damper 307 is movably connected to the surface of the circular guide rod 306, and the inner wall of the linear motion damper 307 is transition-fitted with the surface of the circular guide rod 306.

[0048] A shaft end retaining ring 309 is movably provided on the inner wall of the end of the guide tube 308 away from the linear motion damper 307. The side walls of the guide tube 308 corresponding to the positions of the linear motion damper 307 and the shaft end retaining ring 309 are respectively threaded with fastening screws so that the linear motion damper 307 and the shaft end retaining ring 309 are axially fixed to the inner wall of the guide tube 308. The inner wall of the shaft end retaining ring 309 is threaded with a second screw 310, and the second screw 310 is threaded with the inner wall of the second universal joint 311.

[0049] The shoulder end of the circular guide rod 306 is located on the inner wall of the guide tube 308, and the diameter of the shoulder end of the circular guide rod 306 is larger than the inner diameter of the linear motion damper 307 and the shaft end retaining ring 309. The smooth end of the circular guide rod 306 is located on the inner wall of the first universal joint 302.

[0050] A bearing 402 is rotatably connected to the surface of the connecting shaft of the oscillator center mounting block 401. A groove is formed on the surface of the connecting shaft of the oscillator center mounting block 401, and a bearing retainer 403 is engaged with the inner wall of the groove. The bearing retainer 403 is tightly fitted to one end of the bearing 402. The bearing 402 is located between the bearing retainer 403 and the shoulder of the connecting shaft of the oscillator center mounting block 401, so that the bearing 402 and the connecting shaft of the oscillator center mounting block 401 are axially fixed. The outer ring of the bearing 402 is transitionally fitted with the square hollow guide rod 202, so that the bearing 402 rotates on the surface of the square hollow guide rod 202. The inner ring of the bearing 402 is transitionally fitted with the surface of the connecting shaft of the oscillator center mounting block 401, and the inner wall of the bearing retainer 403 is clearance fitted with the inner wall of the groove on the surface of the connecting shaft of the oscillator center mounting block 401.

[0051] The combination of linear motion damper 307 and spring 304 has the advantages of simple structure and convenient disassembly and assembly. Different specifications of parts can be replaced according to actual needs, that is, the damping of linear motion damper 307 is adjustable, and the stiffness of spring 304 is adjustable.

[0052] The geometric shape of the oscillator center mounting block 401 in the oscillator mass block is variable, that is, the mass of the oscillator mass block is adjustable. There are 7 structures in total: a single oscillator center six-axis structure, a solid and hollow sphere oscillator center six-axis structure, a solid and hollow cylinder oscillator center six-axis structure, and a solid and hollow cube oscillator center six-axis structure. The hollow part inside the oscillator center mounting block 401 can be filled with materials of different densities to change the mass of the oscillator mass block.

[0053] The dynamic vibration absorber bracket and the oscillator center mounting block 401 are both made of high-strength lightweight alloys, such as titanium alloy or aluminum alloy. The spring damper can perform telescopic and rotational movements, and the bearing 402 can roll on the square hollow guide rod 202.

[0054] Working principle: In use, the oscillator mass block is located at the center of the dynamic vibration absorber bracket space. At this time, the springs 304 of the six spring dampers are all in their original length, so the oscillator mass block is stationary. When the engine mount 1 of the vibration damping system has an initial velocity and begins to move (that is, the engine mount 1 initially has a certain amount of energy), it will inevitably drive the dynamic vibration absorber of the vibration damping system to move. That is, the oscillator mass block in this technical solution moves under the traction of the spring dampers. When the oscillator mass block moves in translational motion along the direction of a certain square hollow guide rod 202, such as... Figure 13 As shown, a force F is generated along the axial direction, which can suppress the translational vibration of the engine mount 1 along this axial direction. At this time, the vibrator mass block has a translational vibration absorption and suppression mode; when the vibrator mass block rotates circumferentially around a certain connecting shaft, as... Figure 14 As shown, a circumferential torque T is generated around a certain connecting shaft, which can suppress the circumferential rotational vibration of the engine mount 1 around the connecting shaft. At this time, the oscillator mass block has a rotational vibration absorption and suppression mode; when the oscillator mass block moves both axially along a certain connecting shaft and circumferentially around a certain connecting shaft, as shown... Figure 15 As shown, an axial force F and a circumferential moment T are generated, which can suppress the translational vibration of the engine pylon 1 along the axial direction of the connecting shaft and the circumferential rotational vibration of the connecting shaft. At this time, the oscillator mass block has translational vibration absorption and rotational vibration absorption and suppression modes. This is a dynamic vibration absorption system. When the aircraft engine acts on the engine pylon 1 with energy, this technical solution has a good vibration absorption effect, that is, the vibration absorption system can absorb more energy, thereby reducing the excess energy of the engine pylon 1 and reducing the vibration of the engine pylon 1, thus achieving the effect of vibration reduction, vibration absorption and suppression.

[0055] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0056] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A three-degree-of-freedom adjustable dynamic vibration absorber for an aircraft engine pylon, characterized in that: include: Engine pylon for mounting aircraft engines (1); A power vibration absorber bracket is fixedly installed in the middle of the engine mount (1), and the power vibration absorber bracket is in the form of a Cartesian space coordinate structure; A spring damper is movably installed in the middle of the dynamic vibration absorber bracket. There are six spring dampers. Each spring damper includes a first universal joint (302) fixedly installed inside the dynamic vibration absorber bracket. A circular guide rod (306) is fixedly installed at one end of the first universal joint (302). A guide tube (308) is movably sleeved on the surface of the circular guide rod (306) so that the circular guide rod (306) can move along the direction of the guide tube (308). A spring (304) for suppressing vibration is fixedly installed at one end of the first universal joint (302) and the guide tube (308) corresponding to the position of the circular guide rod (306). A second universal joint (311) is fixedly installed at one end of the guide tube (308) away from the position of the spring (304). The oscillator mass block is set in the middle of the power vibration absorber bracket. The oscillator mass block includes an oscillator center mounting block (401). The surface of the oscillator center mounting block (401) is provided with six connecting shafts, and the six shafts are distributed in a Cartesian space coordinate structure. The six first universal joints (302) are respectively fixedly set at one end of the connecting shaft on the surface of the oscillator center mounting block (401). When the aircraft engine is vibrated, the oscillator center mounting block (401) moves along the direction of the connecting shaft and drives the circular guide rod (306) and the guide tube (308) to move relative to each other, causing the spring (304) to deform, thereby suppressing the vibration generated by the multi-degree-of-freedom of the aircraft engine.

2. The three-degree-of-freedom adjustable dynamic vibration absorber for an aircraft engine pylon according to claim 1, characterized in that: The power vibration absorber bracket includes six square plates (201), and the line connecting the middle of the six square plates (201) forms a Cartesian coordinate system. The four corners of the square plates (201) are fixedly connected to the middle of the engine mount (1) by screws. The four corners of the square plates (201) corresponding to the origin of the coordinate system are respectively fixedly connected to square hollow guide rods (202). The corresponding ends of three adjacent square hollow guide rods (202) are fixedly connected.

3. The three-degree-of-freedom adjustable dynamic vibration absorber for an aircraft engine pylon according to claim 2, characterized in that: The first universal joint (302) is threaded to a first screw (301) at the end away from the circular guide rod (306), and the first screw (301) is threaded to one end of the connecting shaft of the oscillator center mounting block (401). The second universal joint (311) is threaded to a bolt (312) at the end away from the guide tube (308). The bolt (312) is rotatably connected to the middle of the square plate (201) at the end away from the second universal joint (311), and the diameter of the bolt (312) at the end away from the second universal joint (311) is greater than the diameter of the bolt (312) at the end of the second universal joint (311) corresponding to the second universal joint (311), so that the bolt (312) cannot penetrate the square plate (201) from the direction of the corresponding second universal joint (311).

4. The three-degree-of-freedom adjustable dynamic vibration absorber for an aircraft engine pylon according to claim 3, characterized in that: One end of the spring (304) corresponding to the position of the first universal joint (302) is fixedly connected to a first spring retainer (303), and the first spring retainer (303) is tightly fitted to one end of the first universal joint (302). One end of the spring (304) corresponding to the position of the guide tube (308) is fixedly connected to a second spring retainer (305), and the second spring retainer (305) is tightly fitted to one end of the guide tube (308). One end of the circular guide rod (306) corresponding to the position of the first universal joint (302) is threaded, and the circular guide rod (306) is threaded to the inner wall of the first universal joint (302).

5. A three-degree-of-freedom adjustable dynamic vibration absorber for an aircraft engine pylon according to claim 4, characterized in that: The inner wall of the guide tube (308) is movably provided with a linear motion damper (307), and the inner wall of the guide tube (308) and the surface of the linear motion damper (307) are clearance-fitted. The linear motion damper (307) is movably connected to the surface of the circular guide rod (306), and the inner wall of the linear motion damper (307) and the surface of the circular guide rod (306) are transition-fitted.

6. A three-degree-of-freedom adjustable dynamic vibration absorber for an aircraft engine pylon according to claim 5, characterized in that: A shaft end retaining ring (309) is movably provided on the inner wall of one end of the guide tube (308) away from the linear motion damper (307). The side walls of the guide tube (308) corresponding to the positions of the linear motion damper (307) and the shaft end retaining ring (309) are respectively threaded with fastening screws so that the linear motion damper (307) and the shaft end retaining ring (309) are axially fixed to the inner wall of the guide tube (308). The inner wall of the shaft end retaining ring (309) is threaded with a second screw (310), and the second screw (310) is threaded with the inner wall of the second universal joint (311).

7. A three-degree-of-freedom adjustable dynamic vibration absorber for an aircraft engine pylon according to claim 6, characterized in that: The shoulder end of the circular guide rod (306) is located on the inner wall of the guide tube (308), and the diameter of the shoulder end of the circular guide rod (306) is greater than the inner diameter of the linear motion damper (307) and the shaft end retaining ring (309). The smooth end of the circular guide rod (306) is located on the inner wall of the first universal joint (302).

8. A three-degree-of-freedom adjustable dynamic vibration absorber for an aircraft engine pylon according to claim 7, characterized in that: A bearing (402) is rotatably connected to the surface of the connecting shaft of the oscillator center mounting block (401). A groove is formed on the surface of the connecting shaft of the oscillator center mounting block (401), and a bearing retainer (403) is engaged with the inner wall of the groove. The bearing retainer (403) is tightly fitted to one end of the bearing (402). The bearing (402) is located between the bearing retainer (403) and the shoulder of the connecting shaft of the oscillator center mounting block (401) so that the bearing (402) is axially fixed to the connecting shaft of the oscillator center mounting block (401). The outer ring of the bearing (402) is transitionally fitted with the square hollow guide rod (202) so that the bearing (402) rotates on the surface of the square hollow guide rod (202). The inner ring of the bearing (402) is transitionally fitted with the surface of the connecting shaft of the oscillator center mounting block (401). The inner wall of the bearing retainer (403) is clearance fitted with the inner wall of the groove on the surface of the connecting shaft of the oscillator center mounting block (401).

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