Long stroke loading structure

Abstract

The application relates to the technical field of aircraft structure strength test, and discloses a long-stroke loading structure, which is driven to rotate by a servo motor and a speed reducer, so as to drive a spline shaft to rotate, and the rotation of the spline shaft drives a spline sleeve, a roller and a screw nut to rotate simultaneously. The relative rotation between the screw nut and the screw shaft drives the spline sleeve, the roller and the screw nut to move in the same direction, and a pull rope is gradually wound on the roller according to a predetermined track, so that the pull rope is arranged closely and neatly. In the process that the pull rope is wound on the roller, the pull rope between a movable pulley set and a fixed pulley set becomes shorter and shorter, and at this time, the loaded structure can bear a pulling load, so that the loading effect is realized. When unloading, the roller is reversely rotated by the spline shaft, the pull rope is elongated, and the pull rope between the movable pulley set and the fixed pulley set becomes longer and longer, so that the unloading is realized. Compared with an existing long-stroke hydraulic cylinder, the long-stroke loading structure is more compact, and is convenient to debug and install.

Description

Technical Field

[0001] This invention relates to the field of aircraft structural strength testing technology, and discloses a long-stroke loading structure. Background Technology

[0002] Aircraft structural strength testing involves applying simulated loads to an aircraft structure and measuring mechanical parameters such as stress, strain, and displacement. This allows for a correct evaluation and estimation of the aircraft structure's load-bearing capacity and structural lifespan, and provides a reliable basis for verifying and optimizing structural designs.

[0003] In aircraft structural strength tests, long-stroke hydraulic cylinders are conventionally used to load wings that deform significantly. However, long-stroke hydraulic cylinders are not only very long, making installation, debugging, and disassembly difficult, but also require the piston rod to extend during use, further increasing their overall length. This inevitably leads to a taller loading frame for the hydraulic cylinder, higher costs, and greater risks. Summary of the Invention

[0004] The purpose of this invention is to provide a long-stroke loading structure that is shorter, more compact, and easier to debug and install.

[0005] To achieve the above-mentioned technical effects, the technical solution adopted by the present invention is as follows:

[0006] A long-stroke loading structure includes: A base, in which a splined shaft is installed, the splined shaft being driven to rotate by a drive shaft; A roller is coaxially sleeved on the outer circumference of the splined shaft. A splined sleeve that mates with the splined shaft is fixed on the roller. The roller is used to rotate during the rotation of the splined shaft by the engagement of the splined sleeve and the splined shaft. A lead screw nut is provided at the end of the roller away from the splined sleeve to drive the roller to move axially. A lead screw shaft is fitted inside the lead screw nut, one end of which is fixed to the base and coaxial with the roller. A fixed pulley system, wherein the fulcrum of the fixed pulley system is fixed on the base; A movable pulley system, wherein the fulcrum of the movable pulley system is used for a driving connection with the loaded structure; A pull rope is wound between a fixed pulley block and a movable pulley block, and the two ends of the pull rope are respectively fixed to the drum after passing through two guide wheels fixed on the base.

[0007] Furthermore, the two guide wheels are symmetrically distributed in the plane containing the rotation center line of the roller.

[0008] Furthermore, the lead screw shaft is coaxially rotatably connected to the spline shaft.

[0009] Furthermore, the drive shaft is rotated by a servo motor and a reducer that work together.

[0010] Furthermore, the pull rope is a steel wire rope, and the lead of the lead screw shaft is twice the diameter of the pull rope.

[0011] Furthermore, the roller is provided with winding grooves that cooperate with the pull rope. The starting positions of the two sets of winding grooves are arranged opposite each other, and the spiral directions are opposite. The two ends of the pull rope are respectively fixed at the end position of one of the winding grooves.

[0012] Furthermore, the pitch of each winding groove is twice the diameter of the pull rope.

[0013] Furthermore, the roller is provided with a polygonal hole at the position where the lead screw nut is installed. The outer wall of the lead screw nut is a polygonal structure that fits into the polygonal hole. The outer wall of the lead screw nut is floatingly inserted into the polygonal hole. Limiting plates are provided on both end faces of the lead screw nut to prevent the polygonal outer wall of the lead screw nut from coming out of the polygonal hole.

[0014] Compared with existing technologies, the advantages of this invention are as follows: This invention utilizes the rotation of a drive shaft to drive the rotation of a spline shaft, which in turn drives the spline sleeve, roller, and lead screw nut to rotate simultaneously. The relative rotation between the lead screw nut and the lead screw shaft causes the spline sleeve, roller, and lead screw nut to move in one direction simultaneously. The pull rope gradually winds around the roller along a predetermined trajectory, arranging itself tightly and neatly. As the pull rope winds around the roller, the pull rope between the movable and fixed pulley groups becomes shorter and shorter, at which point the loaded structure bears tensile load, thus achieving the loading effect. During unloading, the spline shaft drives the roller to rotate in the opposite direction, the pull rope lengthens, and the pull rope between the movable and fixed pulley groups becomes longer and longer, achieving unloading. Compared with existing long-stroke hydraulic cylinders, the long-stroke loading structure of this invention is shorter, more compact, and easier to debug and install. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the long-stroke loading structure in the embodiment; Figure 2 This is a schematic diagram showing the positional relationship between the roller and the lead screw nut in the embodiment; Figure 3 This is a schematic diagram of the structure of the limiting piece in the embodiment; Among them, 1. movable pulley block; 2. fixed pulley block; 3. lead screw shaft; 4. lead screw nut; 5. roller; 6. spline shaft; 7. spline sleeve; 8. servo motor; 9. base; 10. guide wheel; 11. pull rope; 12. loaded structure; 13. limit plate. Detailed Implementation

[0016] The present invention will now be described in further detail with reference to the embodiments and accompanying drawings. However, this should not be construed as limiting the scope of the above-described subject matter of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0017] Example See Figures 1 to 3 A long-stroke loading structure, comprising: Base 9, in which a splined shaft 6 is installed, the splined shaft 6 being driven to rotate by a drive shaft; A roller 5 is coaxially sleeved around the outer periphery of the spline shaft 6. A spline sleeve 7 that mates with the spline shaft 6 is fixed on the roller 5. The roller 5 is used to rotate during the rotation of the spline shaft 6 by the mate between the spline sleeve 7 and the spline shaft 6. A lead screw nut 4 is provided at the end of the roller 5 away from the spline sleeve 7 to drive the roller 5 to move axially. The lead screw shaft 3 is fitted inside the lead screw nut 4. One end of the lead screw shaft 3 is fixed on the base 9 and is coaxially arranged with the roller 5. Fixed pulley block 2, the fulcrum of which is fixed on base 9; A movable pulley block 1, wherein the fulcrum of the movable pulley block 1 is used for driving connection with the loaded structure 12; The pull rope 11 is wound between the fixed pulley block 2 and the movable pulley block 1. The two ends of the pull rope 11 are respectively fixed to the roller 5 through two guide wheels 10 fixed on the base 9.

[0018] In this embodiment, by fixing the base 9 to the frame, the servo motor 8 and reducer drive the shaft to rotate, thereby rotating the spline shaft 6. The rotation of the spline shaft 6 causes the spline sleeve 7, the roller 5, and the lead screw nut 4 to rotate simultaneously. The relative rotation between the lead screw nut 4 and the lead screw shaft 3 causes the spline sleeve 7, the roller 5, and the lead screw nut 4 to move in one direction simultaneously. The pull rope 11 is wound onto the roller 5 through the guide wheel 10, and the pull rope 11 is gradually wound onto the roller 5 according to a predetermined trajectory, arranged tightly and neatly. During the process of the pull rope 11 winding onto the roller 5, the pull rope 11 between the movable pulley group 1 and the fixed pulley group 2 becomes shorter and shorter. At this time, the loaded structure 12 will bear the tensile load, thereby achieving the loading effect. The unloading process is the opposite. The spline shaft 6 drives the roller 5 to rotate in the opposite direction, the pull rope 11 extends, and the pull rope 11 between the movable pulley group 1 and the fixed pulley group 2 becomes longer and longer, thereby achieving the unloading process. Compared with the existing long-stroke hydraulic cylinder, the long-stroke loading structure of the present invention is shorter, more compact, and easier to debug and install.

[0019] In actual installation, the frame only needs to be fixed on the foundation platform of the test site, and one end of the load-bearing structure 12 to be tested is connected to the bearing hanging point of the moving pulley block 1, and the other end is fixed to the corresponding fixed end of the frame to complete the installation. Unlike long-stroke hydraulic cylinders, there is no need to reserve extra telescopic installation space. For large-span and long-stroke loading tests, the footprint of the entire structure can be reduced by more than 30%, making it more adaptable to projects with limited test site space.

[0020] In this embodiment, the two guide wheels 10 are symmetrically distributed in the plane containing the rotation center line of the roller 5. This arrangement ensures that the pull rope 11 is always under uniform force during winding and releasing, and will not shift laterally due to asymmetry in the tension on both sides. This avoids the pull rope 11 from stacking or misaligning on the roller 5, further ensuring the regularity of the winding arrangement of the pull rope 11, and also extending the service life of the pull rope 11 and reducing the replacement and maintenance costs caused by uneven wear.

[0021] In addition, this design uses a servo motor 8 as the power source. Compared with the traditional hydraulic cylinder loading method that relies on the hydraulic system for pressure regulation and control, it can more accurately control the rotation angle and speed of the roller 5. This also allows for precise control of the length of the pull rope 11 and the loading speed. Whether it is a slow loading of small loads or a fast loading of large loads, the test requirements can be easily achieved by preset the operating parameters of the servo motor 8. The loading accuracy can be controlled within 0.5%, which is far higher than the accuracy level of the traditional hydraulic loading method. It can meet the mechanical performance testing requirements of various long-stroke structures.

[0022] In this embodiment, the lead screw shaft 3 and the spline shaft 6 are coaxially rotatably connected. This coaxial connection ensures the stability of power transmission to the spline shaft 6 and prevents unbalanced radial displacement at the far end of the spline shaft 6. In actual operation, the rotational power output by the servo motor 8 is directly transmitted to the spline shaft 6 through the transmission gear set, but it does not drive the lead screw shaft 3 to rotate synchronously. This does not affect the axial movement of the lead screw nut 4 and ensures that the spline shaft 6 continuously and stably outputs rotational power.

[0023] In this embodiment, the pull rope 11 is a steel wire rope, and the lead of the lead screw shaft 3 is twice the diameter of the pull rope 11. Each time the lead screw nut 4 moves the pulley seat by one lead, the steel wire rope wound around the outer wall of the drum 5 can be tightly arranged. Under the same displacement conditions of the loaded structure 12, the axial dimension of the drum 5 can be reduced, making the overall layout of the loading structure more compact and effectively reducing the overall footprint of the equipment. This makes it easier for companies to complete equipment layout in limited laboratory spaces. At the same time, this tightly wound arrangement also avoids problems such as rope stacking, jamming, and skipping during the wire rope winding and unwinding process, reducing the squeezing friction between the wire ropes. This extends the service life of the wire rope and ensures the stability of the tensile loading process, avoiding unnecessary fluctuations in the loading force due to wire rope misalignment, and improving the accuracy of the test data.

[0024] In this embodiment, the roller 5 is provided with winding grooves that cooperate with the pull rope 11. The starting positions of the two sets of winding grooves are opposite, and the spiral directions are opposite. The two ends of the pull rope 11 are respectively fixed to the end position of one of the winding grooves. When the roller 5 rotates to pull or release the wire rope, the two wire ropes can simultaneously pull inward or release outward, keeping the tension on both sides of the roller 5 in a balanced state. This ensures that each section of wire rope can fit into the winding groove to complete the pulling and releasing, and it is not easy for the wire rope to become loose and slip out of the groove.

[0025] In this embodiment, the pitch of each winding groove is twice the diameter of the pull rope 11. When the roller 5 is rotated to wind and unwind the wire rope, each pull rope 11 can move in an orderly manner in the corresponding winding groove. The adjacent rope segments will not be squeezed together due to the small gap between the grooves, nor will the rope shake and misalign due to the large gap. This ensures the tightness of the winding.

[0026] In this embodiment, the roller 5 has a polygonal hole at the position where the lead screw nut 4 is installed. The outer wall of the lead screw nut 4 is a polygonal structure that fits into the polygonal hole. The outer wall of the lead screw nut 4 is floatingly inserted into the polygonal hole. Limiting plates 13 are provided on both end faces of the lead screw nut 4 to prevent the polygonal outer wall of the lead screw nut 4 from dislodging from the polygonal hole. This ensures that the lead screw nut 4 can stably transmit rotational power to the roller 5, driving the roller 5 to rotate synchronously to complete the rope winding and unwinding actions. At the same time, a certain amount of small axial movement space is reserved. When adjacent rope segments overlap during wire rope (or tension) winding, the position of the roller 5 can be automatically adjusted by axial floating to prevent the rope segments of adjacent turns from overlapping and wearing. It can also buffer the axial stress between the lead screw nut 4 and the lead screw shaft 3, avoiding fatigue wear of the threads of the lead screw shaft 3 or the lead screw nut 4 after long-term stress, and further improving the stability of power transmission.

[0027] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A long-stroke loading structure, characterized in that, include: A base, in which a splined shaft is installed, the splined shaft being driven to rotate by a drive shaft; A roller is coaxially sleeved on the outer circumference of the splined shaft. A splined sleeve that mates with the splined shaft is fixed on the roller. The roller is used to rotate during the rotation of the splined shaft by the engagement of the splined sleeve and the splined shaft. A lead screw nut is provided at the end of the roller away from the splined sleeve to drive the roller to move axially. A lead screw shaft is fitted inside the lead screw nut, one end of which is fixed to the base and coaxial with the roller. A fixed pulley system, wherein the fulcrum of the fixed pulley system is fixed on the base; A movable pulley system, wherein the fulcrum of the movable pulley system is used for a driving connection with the loaded structure; A pull rope is wound between a fixed pulley block and a movable pulley block, and the two ends of the pull rope are respectively fixed to the drum after passing through two guide wheels fixed on the base.

2. The long-stroke loading structure according to claim 1, characterized in that, The two guide wheels are symmetrically distributed in the plane containing the rotation center line of the roller.

3. The long-stroke loading structure according to claim 1, characterized in that, The lead screw shaft and the spline shaft are coaxially rotatably connected.

4. The long-stroke loading structure according to claim 1, characterized in that, The drive shaft is rotated by a servo motor and a reducer that work together.

5. The long-stroke loading structure according to claim 1, characterized in that, The pull rope is a steel wire rope, and the lead of the lead screw shaft is twice the diameter of the pull rope.

6. The long-stroke loading structure according to claim 1, characterized in that, The roller is provided with winding grooves that cooperate with the pull rope. The starting positions of the two sets of winding grooves are arranged opposite each other, and the spiral directions are opposite. The two ends of the pull rope are respectively fixed at the end position of one of the winding grooves.

7. The long-stroke loading structure according to claim 6, characterized in that, The pitch of each winding groove is twice the diameter of the pull rope.

8. The long-stroke loading structure according to claim 1, characterized in that, The roller has a polygonal hole at the position where the lead screw nut is installed. The outer wall of the lead screw nut is a polygonal structure that fits into the polygonal hole. The outer wall of the lead screw nut is floatingly inserted into the polygonal hole. Limiting plates are provided on both end faces of the lead screw nut to prevent the polygonal outer wall of the lead screw nut from coming out of the polygonal hole.

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