An adjustable rigid cushioning structure

Abstract

The application provides an adjustable rigid buffering structure, which comprises a fixing part, a clamp, a tightening screw and a pressing ring, the fixing part is provided with a through hole, and a plurality of screw holes are uniformly distributed along the circumference of the through hole; the outer wall of the clamp on one side in the axial direction is designed with a step structure, which cooperates with the through hole of the fixing part to limit the axial movement of the clamp relative to the fixing part; a plurality of tightening teeth are uniformly distributed along the circumferential direction on the other side of the clamp in the axial direction, the tightening teeth extend along the axial direction of the clamp, and the gap between the adjacent two parts of the tightening teeth is in V shape; a movable straight cylinder passes through the clamp; the pressing ring is provided with a screw hole at the position corresponding to the screw hole of the fixing part, and the tightening screw passing through the screw hole of the pressing ring and the screw hole of the fixing part changes the axial distance between the pressing ring and the fixing part by rotating, so as to adjust the friction between the tightening teeth and the movable straight cylinder. The application has simple structure, adjustable friction, does not use the spring structure and the high-temperature-resistant rubber pad structure which are prohibited in the industry standard, and can meet the use of special aircraft.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of mechanical structure design, and is used for providing displacement of two structural members in one degree of freedom under the premise of ensuring the connection strength, and eliminating the damage of strong impact on the structural members. BACKGROUND

[0002] The controllable aircraft relies on air lift or counter thrust to fly at high altitude, and relies on control devices to adjust the flight attitude. The main components include structural support, power output device, flight control system, etc. Among them, some structural members in the aircraft need to be designed as adjustable structural members to meet the assembly and limiting of the components in the aircraft. The structural members will be affected by jolting, vibration, large overload impact and other loads during the flight and landing of the aircraft. These load effects affect the structural integrity of the aircraft, and the load can cause irreversible damage to the flight control system inside the aircraft, directly affecting the service life of the entire aircraft.

[0003] The current adjustable structural members, such as height-adjustable tables and chairs, basically use movable parts to adjust the height and use screws or directly use threads for fastening. Some height-adjustable tables directly use hydraulic struts or motor-gear pairs for adjustment and fixation. For example, the metal support with adjustable height of the layer plate in the kitchen and bathroom is designed to insert the slot on the metal movable support into the insertion pair on the fixed part for insertion and fixation.

[0004] The existing similar adjustable structure is used to limit the movement of the adjustable structural member in a certain degree of freedom, without buffering and damping function, which can meet the adjustment function in the assembly process of the aircraft, but cannot meet the buffering and damping function of the load.

[0005] The structure with rigid buffering function in the existing design is a spring buffering and rubber pad buffering structure. The main reasons why the spring buffering and rubber pad buffering structure cannot meet the buffering and damping function requirements of the aircraft are as follows:

[0006] 1) The flight vibration level of the aircraft is large, and the structural member needs to have a buffering device to offset part of the impact force;

[0007] 2) In order to meet the flight reliability requirements in the industry standard, the design criteria do not allow the use of spring structure;

[0008] 3) A large amount of heat is generated by air friction during high-altitude flight, and the melting point of the rubber pad material is relatively low, which cannot meet the use requirements;

[0009] 4) For structural members with high safety factor requirements, the structural scheme in the civil field takes economy as the starting point of design, and the civil structural design method cannot meet the requirements of special aircraft.

[0010] Based on the above analysis, the current buffering technology cannot meet the use requirements of the aircraft, and the research in this direction is urgently needed. SUMMARY

[0011] In order to overcome the shortcomings of the prior art, the application provides an adjustable rigid buffering structure, which can realize the size adjustment of the aircraft and realize the buffering and damping functions.

[0012] The technical scheme adopted by the application to solve the technical problems is: an adjustable rigid buffering structure, comprising a fixing member, a clamp, a tightening screw and a pressing ring.

[0013] The fixing member is provided with a through hole, and a plurality of screw holes are uniformly distributed along the circumference around the through hole;

[0014] The outer wall of the clamp on one side in the axial direction is designed with a step structure, which cooperates with the through hole on the fixing member to limit the axial movement of the clamp relative to the fixing member; a plurality of tightening teeth are uniformly distributed in the circumferential direction on the other side of the clamp in the axial direction, the tightening teeth extend in the axial direction of the clamp, and the gap between adjacent two tightening teeth is in V shape; the movable straight cylinder passes through the clamp;

[0015] The inner diameter of the pressing ring is smaller than the outer diameter of the clamp at the position of the extending tightening teeth and larger than the outer diameter of the tightening teeth all gathered to form a circular shape; the pressing ring is provided with a screw hole at the position corresponding to the screw hole of the fixing member, and the tightening screw passing through the screw hole of the pressing ring and the screw hole of the fixing member changes the axial distance between the pressing ring and the fixing member by rotating, so as to adjust the friction force between the tightening teeth and the movable straight cylinder.

[0016] The clamp is made of flexible polytetrafluoroethylene.

[0017] The tightening teeth are designed as 12 teeth.

[0018] The outer wall of the tightening teeth is designed as a wedge-shaped structure with an inclined surface.

[0019] The included angle of the inclined surface of the outer wall of the tightening teeth relative to the axis is 8°.

[0020] The inner wall of the pressing ring has a chamfer towards the edge of the clamp side and is designed as a matching surface with the same inclination as the wedge-shaped structure of the tightening teeth.

[0021] The beneficial effects of the application are: by designing the clamp-pressing ring device between the butt joint surface of the movable straight cylinder and the fixing member, the buffering function under the condition of rigid body impact vibration is realized. By using the friction force, on the one hand, the adjustable moving part is fixed according to the use requirements, and on the other hand, the adjustable moving part can unload the impact force by sliding through friction when subjected to the impact force.

[0022] The buffer device used in the application only has two structural members, i.e. the clamp and the pressing ring, compared with the existing adjustable movable components, such as the screw positioning structural member, the hydraulic support rod or the adjusting structure of the motor-gear pair, the buffer and shock absorption advantages are obtained, and compared with the hydraulic support rod structure and the motor-gear pair structure, the simple structure, the flexible realization and the low cost advantages are obtained.

[0023] According to the different movable component external structures, the envelope size of the clamp and the pressing ring can be freely designed, and the flexible and wide application characteristics are obtained.

[0024] The spring structure and the high-temperature-resistant rubber pad structure which are forbidden in the industry standard are not used, the use of the special aircraft can be met, and the buffer member design in other special industries can be popularized.

[0025] The metal structural member is fastened by the friction force, the friction force size can be adjusted, the materials with different friction resistance values can be changed according to the different fastening requirements, and the flexible and adjustable characteristics are obtained. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is the assembly schematic diagram of the application;

[0027] Figure 2 is the friction pre-tightening force adjustment process schematic diagram of the application;

[0028] Figure 3 is the buffer and shock absorption structure function verification test device schematic diagram;

[0029] Figure 4 is the buffer and shock absorption structure function verification test result comparison situation schematic diagram, wherein (a) is the impact response curve of the rigid connection, and (b) is the impact response curve of the buffer and shock absorption device;

[0030] In the figure, 1-M3x20 tightening long screw; 2-clamp; 3-pressing ring; 4-adjustable straight cylinder section. DETAILED DESCRIPTION

[0031] The application will be further described below in combination with the drawings and the embodiments, and the application includes but is not limited to the following embodiments.

[0032] The adjustable structure provided by the application comprises a fixed part 1, a clamp 2, a pressing ring 3 and a movable straight cylinder segment 4, so that the movable straight cylinder segment has size adjustment and impact buffering capability relative to the X direction (axial direction). The working principle of the adjustable rigid buffering structure is as follows: the clamp is made of flexible polytetrafluoroethylene, the clamp is designed to have petals arranged in the axial direction and has a certain expansion angle of the tightening teeth. The clamp is assembled in the fixed part and remains unchanged, the tightening teeth are in an expanded state at this time, the inner diameter of the expanded segment is larger than the outer diameter of the movable straight cylinder segment, and the movable straight cylinder segment can freely adjust the size in the axial direction (X direction). When the straight cylinder segment needs to be limited, another structure, i.e., the pressing ring, is sleeved outside the tightening teeth of the clamp, the pressing ring is moved towards the fixed part by using six M3*20mm long screws, the expansion angle of the pressing ring is continuously reduced, until the tightening teeth are tightly attached to the movable straight cylinder segment, the friction force between the tightening teeth and the straight cylinder segment is increased, and the purpose of fastening the straight cylinder segment is achieved.

[0033] In the formula, the tightening teeth are designed to be 12, the single tightening tooth is designed to have a wedge-shaped structure with a certain slope (8°) (the friction coefficient between the surface of the tightening tooth and the metal surface is 0.1-0.15), the inner hole of the pressing ring is designed to have a chamfer and the inner circular surface is designed to have the same slope as the wedge-shaped structure of the tightening tooth, and the pressure on the tightening tooth is increased. The fastening force of the clamp and the straight cylinder segment is the friction force, so that the straight cylinder segment has the buffering and damping function when the axial impact force exceeding the friction force is applied to the straight cylinder segment. The size of the fastening force of the straight cylinder segment can be adjusted by adjusting the fastening force of the pressing ring on the clamp, and the buffering and damping capability of the straight cylinder segment can be adjusted.

[0034] As shown in the embodiment of the application, Figure 1 , Figure 2 first, the clamp is clamped in the center hole of the fixed part (the clamp is designed to have a limiting surface), the pressing ring is sleeved outside the adjustable straight cylinder segment (the straight cylinder segment is not shown in the Figure 1 ), and the straight cylinder segment is inserted into the inner hole of the clamp. After the M3*20 screw is inserted into the corresponding screw hole of the pressing ring through the through hole of the fixed part, the six M3*20mm long screws are continuously screwed, the pressing ring is moved towards the fixed part (as shown in Figure 2 ), and the expansion angle of the tightening tooth is continuously pressed during the movement of the pressing ring, so that the contact surface between the tightening tooth and the straight cylinder segment is continuously increased. When the friction force between the tightening tooth and the straight cylinder segment reaches the preset value, the purpose of fastening the straight cylinder segment is achieved (the movement of the straight cylinder segment in the X direction is limited).

[0035] The adjustable rigid buffering structure is applied to the structure of the bearing flight control system for impact response test verification:

[0036] After the product provided with the adjustable rigid buffering structure is installed on the test tool, the whole is installed on the vibration test table for impact test verification, and the assembly condition is as shown inFigure 3 as shown.

[0037] The test conditions are: along the axial frequency 10Hz-1000Hz\9dB / OCT, 1000Hz-5000Hz\1800g impact response test. The test is carried out in two states of installing buffer damping device and not installing buffer damping device, and the test results are shown in Figure 4 .

[0038] From Figure 4 it can be seen that in the low frequency vibration range of 10Hz-1000Hz, the vibration retention effect of the rigid connection structure and the buffer device connection structure on the flight control device is basically the same; under the high frequency vibration condition of 1000Hz-5000Hz, the shock absorption effect of the structure with the buffer damping device on the flight control device is obviously better than that of the pure rigid structure, as shown by the point marked on the right end of the curve in Figure 4 the buffer damping device buffers the impact vibration.

Claims

1. An adjustable rigid buffer structure, comprising a fastener, a clamp, a tightening screw, and a pressure ring, characterized in that, The fastener has a through hole, and several screw holes are evenly distributed around the through hole along the circumference. The clamp has a stepped structure on the outer wall on one axial side, which cooperates with the through hole on the fastener to restrict the axial movement of the clamp relative to the fastener. Several tightening teeth are evenly distributed circumferentially on the other axial side of the clamp. The tightening teeth extend along the clamp's axial direction, and the gap between two adjacent tightening teeth is V-shaped. The movable straight section passes through the clamp. The inner diameter of the pressure ring is smaller than the outer diameter of the clamp extending from the tightening teeth position and larger than the outer diameter of the circle formed by all the tightening teeth. The pressure ring has screw holes corresponding to the screw holes of the fastener. The tightening screws passing through the screw holes of the pressure ring and the fastener change the axial distance between the pressure ring and the fastener by rotation, thereby adjusting the friction between the tightening teeth and the movable straight section. The clamp is made of flexible polytetrafluoroethylene. The outer wall of the tightening teeth is designed as a wedge-shaped structure with an inclined surface. The angle between the inclined surface of the outer wall of the tightening teeth and the axis is 8°.

2. The adjustable rigid buffer structure according to claim 1, characterized in that, The tightening teeth are designed with 12 teeth.

3. The adjustable rigid buffer structure according to claim 1, characterized in that, The inner wall of the pressure ring has a chamfered edge on the side facing the clamp, and the inner wall is designed as a mating surface with the same slope as the tightening tooth wedge structure.

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