Strength test restraining device for releasing rotational degree of freedom

Abstract

The invention belongs to an aircraft ground test technology, and relates to a strength test restraining device for releasing rotational degree of freedom. Comprising a rubber cushion plate, a cover plate, an adapter plate, a force bearing shaft, a rocker arm support, a bearing support, a base, a first bearing a, a second bearing b and a locking nut. The device restrains the degree of freedom and releases the degree of freedom. Translation in the X direction and the Y direction is restrained by the rocker arm support. Translational motion in the Z direction is restrained by a force bearing assembling assembly composed of a force bearing shaft, a bearing support, a first bearing, a second bearing and a locking nut; the rotation in the X direction and the rotation in the Y direction are restrained by the bearing assembling assembly and the base. When the device is used for a sleigh undercarriage static test, the real installation state of the sleigh undercarriage can be completely simulated, and the rubber cushion plate can protect the sleigh undercarriage from being knocked and can also realize the real tire contact condition; the oval areas of the cover plate and the adapter plate simulate the actual contact area of the tire and the sleigh undercarriage, and the stress area is real.

Description

Technical Field

[0001] The invention belongs to aircraft ground test technology and relates to a strength test restraint device for releasing rotational freedom. Background Art

[0002] In order to allow the aircraft to take off and land on the snow, a sled landing gear is installed on the wheeled landing gear of the aircraft. The strength of the sled landing gear needs to be verified by static testing. In the past, when the wheeled landing gear was subjected to static testing, all the degrees of freedom in the six directions were constrained. However, for the static strength test of the sled landing gear, it is necessary to provide it with translational constraints in the X, Y, and Z directions and rotational constraints in the X and Y directions, and release the Z-direction rotational degree of freedom. This is quite different from the conventional test constraint method. Therefore, a strength test constraint device that releases the rotational degree of freedom is designed to meet the constraint requirements of the static test of the sled landing gear. Summary of the invention

[0003] Purpose of the Invention

[0004] The purpose of the present invention is to design a strength test restraint device for releasing the rotational freedom. The strength test restraint device for releasing the rotational freedom provided by the present invention can provide translational restraints in the X, Y and Z directions and rotational restraints in the X and Y directions when conducting a static test on a sled landing gear, and release the rotational freedom in the Z direction.

[0005] Technical Solution

[0006] The present invention provides a strength test restraint device for releasing rotational freedom, which is used for static test restraint of a sled landing gear. The test restraint device includes a rubber pad 1, a cover plate 2, an adapter plate 3, a load-bearing shaft 4, a rocker arm support 5, a bearing support 6, a base 7, a first bearing 8a, a second bearing 8b, and a locking nut 9.

[0007] The four corners of the base 7 are fixed to the load-bearing ground rail with anchor bolts, and the first bearing 8a and the second bearing 8b are installed in the grooves on the upper and lower sides of the bearing support 6, one positive and one negative, respectively. The load-bearing shaft 4 passes through the two first bearings 8a and the second bearing 8b and stops when it contacts the first bearing 8a. A locking nut 9 is installed on the threaded end of the load-bearing shaft 4, and the second bearing 8b is pressed into the lower groove of the bearing support 6 to form a load-bearing assembly component, and then the load-bearing assembly component is installed to the end face of the base 7, and the bearing support 6 is connected to the base 7 by bolts. The load-bearing shaft 4 passes through the upper surface through hole on the base 7, and the load-bearing shaft 4 can rotate freely.

[0008] The adapter plate 3 is connected to the conical end face of the load-bearing shaft 4 by bolts, and the cover plate 2 and the rubber pad 1 are placed on the adapter plate 3 in sequence, and the three are connected by bolts. At this time, the cover plate 2 and the rubber pad 1 can rotate freely along the Z axis with the load-bearing shaft 4, but cannot move in the X, Y, and Z directions, and cannot rotate along the X and Y axes. Two symmetrical rocker arm supports 5 are fixed to the upper end faces of the bearing supports 6 by bolts.

[0009] Furthermore, the spacing of the symmetrical rocker arms 5 is determined by the rocker arm spacing of the ski landing gear.

[0010] Furthermore, a long slot hole along the X direction is provided on the bottom plate of the rocker arm support 5 .

[0011] Furthermore, the upper end surface of the bearing support 6 is provided with a long slot hole along the Y direction.

[0012] Furthermore, the sled landing gear is mounted on the surface of the rubber pad 1 and is fixed by bolts which pass through the sled landing gear, the rubber pad 1, the cover plate 2 and the adapter plate 3 in sequence.

[0013] Furthermore, the rocker arm support 5 is a fork ear structure, which limits the movement of the sled landing gear in the Y-axis direction through the end surface of the fork ear, and limits the movement of the sled landing gear in the X-axis direction through the axis in the middle of the fork ear.

[0014] Furthermore, the height of the conical end surface of the load-bearing shaft 4 is determined by the working height of the rocker arm of the sled landing gear.

[0015] Furthermore, the diameter of the lower end surface of the tapered end surface is determined by the size of the selected bearing.

[0016] Furthermore, the diameter of the upper end surface of the tapered end surface is determined by the tire projection area of ​​the ski landing gear.

[0017] Furthermore, a groove is provided on the adapter plate 3 , and after the head end face of the sunken bolt extends into the groove, the sunken bolt connects the adapter plate 3 and the load-bearing shaft 4 .

[0018] Furthermore, there are a plurality of sunken bolts, which are evenly distributed on the adapter plate 3 .

[0019] Furthermore, the cover plate 2, adapter plate 3, bearing shaft 4, rocker arm support 5, bearing support 6, base 7, first bearing 8a, and second bearing 8b are all metal rigid parts. Furthermore, the bearing is a thrust spherical roller bearing, which can withstand a large axial force and a certain proportion of radial force.

[0020] The beneficial effects of this application are:

[0021] Compared with the previous device that constrained 6 degrees of freedom, this device constrained 5 degrees of freedom and released 1 degree of freedom. Among them, the translation in the X and Y directions is constrained by the rocker support 5; the translation in the Z direction is constrained by the load-bearing assembly composed of the load-bearing shaft 4, the bearing support 6, the first bearing 8a, the second bearing 8b and the locking nut 9; the rotation in the X and Y directions is constrained by the load-bearing assembly and the base 7.

[0022] When the device is used to perform a static test on a sled landing gear, the actual installation state of the sled landing gear can be fully simulated, wherein the rubber pad 1 can protect the sled landing gear from being damaged and realize a real tire contact condition; the elliptical area of ​​the cover plate 2 and the adapter plate 3 simulates the actual contact area between the tire and the sled landing gear, and the force-bearing area is real.

[0023] The device realizes translational constraints in the X, Y and Z directions and rotational constraints in the X and Y directions, and releases the rotational freedom in the Z direction, which is not common in experiments. The present invention provides a solution, and each degree of freedom can be selectively constrained and released as needed. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic diagram of the restraint device structure;

[0025] Figure 2 is a cross-sectional view of the restraint device;

[0026] Figure 3 It is a top view of the restraint device;

[0027] Figure 4 It is a schematic diagram of the rocker arm support;

[0028] Figure 5 A schematic diagram of the base. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the implementation of the present invention clearer, the technical scheme in the embodiment of the present invention will be described in more detail in combination with the embodiment of the present invention. In the example, the same or similar reference numerals throughout represent the same or similar originals or elements with the same or similar functions. The described embodiments are part of the embodiments of the present invention, not all of them. The embodiments described below by reference are exemplary and intended to be used to explain the present invention, and should not be construed as limitations on the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present invention. The following is a detailed description in combination with the embodiments of the present invention.

[0030] The rubber pad 1 is an elliptical structure, simulating the projection area of ​​the tire after compression in the plane, and is between the sled landing gear and the restraint device to protect the sled landing gear.

[0031] The cover plate 2 is an elliptical structure, simulating the projection area of ​​the tire after compression in the plane.

[0032] The adapter plate 3 is an elliptical structure with a countersunk hole in the middle and mounting holes around it.

[0033] The load-bearing shaft 4 is a stepped shaft, one end of which is connected to the sled landing gear and is designed to be conical in order to increase strength. The end face has a threaded hole for connection, and the other end of the stepped shaft is designed to be threaded for fixing.

[0034] The rocker arm support 5 is a fork-shaped structure, with a mounting hole on the fork ear connected to the rocker arm of the sled landing gear, and a long groove mounting hole on the bottom plate.

[0035] The bearing support 6 is a welded part with a conical structure, and has mounting holes on the upper and lower end faces. The mounting hole on the upper end face is in the shape of a long groove.

[0036] The base 7 is a welded piece of a steel plate and a square steel, with threaded holes on the surface of the steel plate and a through hole in the center.

[0037] The bearing 8 is a standard part and can bear a large axial force and a certain radial force.

[0038] The locking nut 9 is a machined part.

[0039] Embodiment 1:

[0040] Figure 1 , Figure 2 , Figure 3 It is a structural schematic diagram of the present invention, combined with Figure 1 , Figure 2 , Figure 3 As shown, this embodiment provides a strength test restraint device for releasing the rotational freedom, which is used for static test of sled landing gear, and the restraint device includes a rubber pad 1, a cover plate 2, an adapter plate 3, a load-bearing shaft 4, a rocker arm support 5, a bearing support 6, a base 7, a first bearing 8a / a second bearing 8b, and a locking nut 9.

[0041] After the device is assembled as shown in the figure, when the sled landing gear is installed and its rocker arm is not connected to the rocker arm support 5, the sled landing gear can rotate freely along the Z axis along the load-bearing shaft 4, and cannot move horizontally along the X, Y and Z directions, and cannot rotate along the X and Y axes, satisfying the constraint requirements. At this time, forces Fx, Fy and Fz are applied to the sled landing gear to test the strength of the main structure of the sled landing gear.

[0042] When the rocker arm of the sled landing gear is connected to the rocker arm support 5 and the rocker arm support 5 is connected to the bearing support 6, the sled landing gear cannot rotate along the Z axis, and the rotational freedom is limited by the rocker arm support 5. At this time, a torque Mz is applied to the sled landing gear to test the strength of the rocker arm of the sled landing gear. In order to make the left and right rockers of the sled landing gear symmetrical along the XZ plane passing through the axis of the load-bearing shaft 4 and ensure that the rocker arm support 5 can be connected to the bearing support 6, the connecting holes of the rocker arm support 5 and the bearing support 6 are designed to be long grooves at 90° to each other, so that the installation range of the connecting bolts is increased. At this time, the restraining force that limits the rotational freedom comes from the friction between the two, which is related to the pre-tightening force of the connecting bolts between the two, which is an unstable factor. Therefore, after determining the position of the rocker arm support 5 and connecting it to the bearing support 6, positioning pins are respectively arranged on both sides of each rocker arm support, and the restraining force that limits the rotational freedom becomes the friction between the two and the positioning pins to be shared, which can ensure a firm installation.

[0043] It is understood by those skilled in the art that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as the general understanding of ordinary technicians in the field to which the present invention belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and unless defined as here, will not be interpreted with idealized or overly formal meanings. The specific implementation methods described above further describe the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the present invention. Within the spirit and principle of the present invention, any technician familiar with the profession may use the above disclosed technical content to change or modify it into an equivalent embodiment of equivalent changes for application in other fields, but any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the technical solution content of the present invention, any modification, equivalent replacement, improvement, etc., made according to the technical essence of the present invention, should be included in the protection scope of the present invention.

Claims

1. A strength test restraint device for releasing rotational freedom, characterized in that: It includes a rubber pad, a cover plate, an adapter plate, a load-bearing shaft, a rocker arm support, a bearing support, a base, a first bearing, a second bearing, and a locking nut; The four corners of the base are fixed to the load-bearing ground rails with anchor bolts, and the first bearing a and the second bearing b are respectively installed in the grooves on the upper and lower sides of the bearing support, one positive and one negative, and the load-bearing shaft passes through the two first bearings and the second bearing until it contacts the first bearing and stops, and a locking nut is installed on the threaded end of the load-bearing shaft, and the second bearing is pressed into the lower groove of the bearing support to form a load-bearing assembly component, and then the load-bearing assembly component is installed to the end face of the base, and the bearing support is connected to the base by bolts, and the load-bearing shaft passes through the upper surface through hole on the base, and the load-bearing shaft can rotate freely; The adapter plate is connected to the conical end face of the load-bearing shaft by bolts, and a cover plate and a rubber pad are placed on the adapter plate in sequence, and the three are connected by bolts. At this time, the cover plate and the rubber pad can rotate freely along the Z axis with the load-bearing shaft, but cannot move horizontally along the X, Y, and Z directions, and cannot rotate along the X and Y axes; two symmetrical rocker arm supports are fixed to the upper end face of the bearing support by bolts.

2. The restraint device according to claim 1, characterized in that The spacing of the symmetrical rocker arm supports is determined by the spacing of the rocker arms of the sled landing gear; a long slot hole along the X direction is arranged on the bottom plate of the rocker arm support; and a long slot hole along the Y direction is arranged on the upper end surface of the bearing support.

3. The restraint device according to claim 1, characterized in that: The sled landing gear is installed on the surface of the rubber pad and is fixed after bolts pass through the sled landing gear, the rubber pad, the cover plate and the adapter plate in sequence.

4. The restraint device according to claim 1, characterized in that: The rocker arm support is a fork ear structure, which limits the movement of the sled landing gear in the Y-axis direction through the end surface of the fork ear, and limits the movement of the sled landing gear in the X-axis direction through the axis in the middle of the fork ear.

5. The restraint device according to claim 1, characterized in that: The height of the conical end surface of the load-bearing shaft is determined by the working height of the rocker arm of the sled landing gear.

6. The restraint device according to claim 1, characterized in that: The diameter of the lower end face of the tapered end face is determined by the size of the selected bearing; the diameter of the upper end face of the tapered end face is determined by the tire projection area of ​​the sled landing gear.

7. The restraint device according to claim 1, characterized in that: The adapter plate is provided with a groove, and after the head end face of the sunken bolt extends into the groove, the sunken bolt connects the adapter plate and the load-bearing shaft.

8. The restraint device according to claim 1, characterized in that There are several sunken bolts, which are evenly distributed on the adapter plate.

9. The restraint device according to claim 1, characterized in that: The cover plate, the adapter plate, the load-bearing shaft, the rocker arm support, the bearing support, the base, the first bearing and the second bearing are all metal rigid parts.

10. The restraint device according to claim 1, characterized in that The bearing is a thrust spherical roller bearing.

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