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CN-121990164-A - Aircraft seat vibration reduction system and design method thereof

CN121990164ACN 121990164 ACN121990164 ACN 121990164ACN-121990164-A

Abstract

The invention discloses an aircraft seat vibration reduction system and a design method thereof, and belongs to the technical field of aircraft structural dynamic strength. The system comprises two vibration absorbers distributed left and right, each vibration absorber consists of a shell, a spring piston rod system, a wear-resisting system, a motion connecting piece and a fastening screw, wherein the spring piston rod system is accommodated in the shell and keeps a radial gap of 1-2mm with the inner wall of the shell, a piston rod of the spring piston rod system is coaxial with the shell, and an upper spring and a lower spring are pre-compressed in parallel. The design method comprises the steps of determining vibration isolation target frequency based on a PSD curve of the seat joint, calculating system design frequency and total rigidity, calculating single spring rigidity according to a parallel structure, determining geometric parameters of the single spring rigidity, designing all part sizes in a coordinated mode, performing interference inspection, and finally manufacturing and installing. The system has compact structure, adjustable rigidity and high vibration isolation rate, can effectively attenuate the vibration transmitted to the seat by the machine body, has scientific design method, and solves the problems that the vibration environment of the aircraft seat is difficult to predict and the later optimization is difficult.

Inventors

  • LUO JIE
  • MA JUNFENG
  • LIU JIJUN
  • WANG CHUN
  • LI KAIXIANG

Assignees

  • 中国飞机强度研究所

Dates

Publication Date
20260508
Application Date
20260115

Claims (10)

  1. 1. The aircraft seat vibration reduction system is characterized by comprising two vibration absorbers distributed left and right, wherein the vibration absorbers comprise a shell (1), a spring piston rod system (2), a wear-resistant system (3), a motion connecting piece (4) and a fastening screw (5); The shell (1) comprises a straight cylinder (102) and left and right connecting lugs (101) arranged on the side part of the straight cylinder (102), a reserved internal thread (103) is arranged at the top of the straight cylinder (102), a clamp spring reserved groove (105) is formed in the top end surface of the straight cylinder (102), and a bottom hole (106) is formed in the bottom of the straight cylinder; The spring piston rod system (2) and the wear-resistant system (3) are accommodated in a straight cylinder (102) of the shell (1); the spring piston rod system (2) comprises an upper spring (201) and a lower spring (202) which are coaxially arranged on a piston rod (203), the piston rod (203) and the straight cylinder (102) are coaxially arranged, and the lower end of the piston rod (203) is provided with external threads and extends out of the bottom hole (106) to be connected with the motion connecting piece (4); The fastening screw (5) is connected with the reserved internal thread (103) through an external thread, the lower end face of the fastening screw (5) is used for compressing the spring piston rod system (2), and the clamp spring reserved groove (105) is used for accommodating a clamp spring so as to axially lock the fastening screw (5) after being screwed.
  2. 2. The aircraft seat vibration reduction system according to claim 1, wherein the piston rod (203) is of an integrally formed structure comprising an upper link (20301), a middle platform (20302) and a lower link (20303), the outer diameter of the middle platform (20302) being greater than the outer diameters of the upper and lower springs (201, 202), the diameters of the upper and lower links (20301, 20303) being smaller than the inner diameters of the upper and lower springs (201, 202).
  3. 3. Aircraft seat vibration damping system according to claim 2, characterized in that the intermediate platform (20302) is provided with an annular groove for mounting a wear ring (302).
  4. 4. Aircraft seat vibration damping system according to claim 1, characterized in that the radially outermost end of the spring piston rod system (2) has a radial clearance of 1mm to 2mm with the inner wall of the straight barrel (102).
  5. 5. Aircraft seat vibration damping system according to claim 1 or 4, characterized in that the upper spring (201) and the lower spring (202) are of the same stiffness and geometry and are both in a pre-compressed state, together forming a parallel spring structure.
  6. 6. The aircraft seat vibration reduction system according to claim 1 or 4, wherein the wear block (3) comprises a wear block (304), the wear block (304) being provided with a first boss (30401), a second boss (30402) and a third boss (30403) nested within each other, wherein the first boss (30401) cooperates with the bottom hole (106) and the third boss (30403) provides a support surface for the lower spring (202).
  7. 7. A method of designing an aircraft seat vibration reduction system, comprising the steps of: acquiring a vibration environment PSD curve at the joint of the aircraft seat, and extracting the energy concentration frequency as a vibration isolation target frequency ; According to a single degree of freedom vibration isolation theory, setting a damping ratio and a target vibration isolation rate of a seat system, calculating a required frequency ratio according to the damping ratio and the target vibration isolation rate, and further according to the vibration isolation target frequency Determining the design frequency of the vibration damping system in relation to said frequency ratio ; Based on the total mass of the seating system The design frequency Using the formula Calculating the total stiffness required for a vibration damping system ; According to the structure that the vibration reduction system is formed by connecting two vibration absorbers in parallel and each vibration absorber comprises two springs connected in parallel, the design rigidity of a single spring is calculated And according to the design rigidity Determining geometric parameters of the spring according to installation space constraint and rigidity requirements; Taking the geometric parameters of the springs as references, coordinating and designing the sizes of a shell (1), a spring piston rod system (2), a wear-resisting system (3), a moving connecting piece (4) and a fastening screw (5) of the shock absorber, and performing interference check to ensure that the shock absorbing system does not collide with a rear structure of the seat; the shock absorber is manufactured and assembled to design dimensions and the assembled shock absorbing system is installed at the aircraft seat joint.
  8. 8. The design method of claim 7, wherein the target vibration isolation ratio is greater than 80%.
  9. 9. The design method according to claim 7, wherein the formula is Calculating the design stiffness of a single spring 。
  10. 10. Design method according to claim 7, characterized in that the upper spring (201) and the lower spring (202) of the spring piston rod system (2) are precompressed by screwing the fastening screw (5) when the shock absorber is assembled, and after reaching the amount of precompression determined according to the design, a snap spring is installed in a snap spring reserve groove (105) of the housing (1) to fix the fastening screw (5).

Description

Aircraft seat vibration reduction system and design method thereof Technical Field The invention belongs to the technical field of dynamic strength of aircraft structures, and particularly relates to an aircraft seat vibration reduction system and a design method thereof. Background When the aircraft flies in the air, the aircraft is influenced by pneumatic load, an engine and airborne equipment, and vibration is inevitably generated. These vibrations are transmitted through the fuselage structure to the pilot's seat, which can cause discomfort to the pilot, affect its piloting operation and precise handling of the weapon equipment system, and may even induce flight accidents in severe cases. In conventional aircraft seat designs, the static and dynamic nature of the seat itself is often focused on, and there is a lack of effective means of predicting vibration transfer from the fuselage joints after installation. Often, vibration problems are only exposed when the aircraft is flown. However, at this point the aircraft has entered or completed the navigable approval stage, any minor modification to the aircraft structure or seating system may trigger the re-approval process, resulting in significant effort and cost. In addition, the dynamic characteristic coupling between the aircraft structure and the seat system is complex, and the optimal design of the aircraft structure and the seat system is a challenge. Therefore, there is a need for a vibration damping system and a matching design method that has a simple structure, high-efficiency vibration isolation, easy installation, and no influence on the original performance of an aircraft, so as to effectively attenuate the vibration transmitted to a seat in the later stage of the aircraft design or in the refitting stage, and ensure safety and comfort of pilots. Disclosure of Invention The invention aims to provide an aircraft seat vibration reduction system and a design method thereof, aiming at the defects that the vibration of an aircraft seat is difficult to predict and the optimization of later vibration reduction is difficult in the prior art. The system can be directly arranged at the joint of the existing seat, the vibration level transmitted from the machine body to the seat is obviously reduced by utilizing the single-frequency vibration isolation characteristic of the system, and the design method is scientific and efficient based on the actually measured vibration environment, so that the rapid customized design of the system can be realized. In order to achieve the above purpose, the invention adopts the following technical scheme: in a first aspect, the present invention provides an aircraft seat vibration reduction system comprising two vibration absorbers distributed symmetrically or asymmetrically about the aircraft seat. The single shock absorber includes a housing, a spring piston rod system, a wear system, a kinematic connection and a fastening screw. The shell comprises a straight cylinder and left and right connecting lugs arranged on the side part of the straight cylinder. The top of the straight cylinder is provided with a reserved internal thread, the end face of the top is provided with a reserved groove for the clamp spring, and the bottom is provided with a bottom hole. The left and right connecting lugs are provided with mounting holes for being connected with the aircraft seat joint through bolts, and the specific shape and the specific size of the mounting holes can be adjusted according to the positions of the seat joint connecting holes and the supporting surface; The spring piston rod system and the wear-resistant system are accommodated in a straight cylinder of the shell; The spring piston rod system comprises a piston rod, an upper spring and a lower spring coaxially sleeved on the piston rod, the piston rod is coaxially arranged with a straight cylinder of the shell, the lower end of the piston rod is provided with external threads, and the lower end of the piston rod extends out of a bottom hole at the bottom of the shell and is used for being in threaded connection with the motion connecting piece; The wear-resisting system comprises an upper gasket, a lower gasket, a wear-resisting ring and a wear-resisting block, and is used for reducing wear between kinematic pairs; The fastening screw is connected with the reserved internal thread at the top of the shell through the external thread, the lower end face of the fastening screw is used for downwards compressing the spring piston rod system, the reserved groove of the clamping spring is used for installing the clamping spring after the fastening screw is screwed to a designed position, and the fastening screw is axially locked to prevent the fastening screw from loosening. Preferably, the piston rod is of an integrated structure and comprises an upper connecting rod, a middle platform and a lower connecting rod. The outer diameter of the middle platform is larger than t