Large-tonnage multi-degree-of-freedom joint

Abstract

The utility model belongs to the technical field of airplane structure test loading, and particularly relates to a large-tonnage multi-degree-of-freedom joint and connecting shaft, which comprises a shaft body and shaft necks positioned on two axial sides of the shaft body, the diameter of the shaft necks is smaller than that of the shaft body, and the shaft necks comprise short-side shaft necks and long-side shaft necks longer than the short-side shaft necks; a first thrust knuckle bearing and a second thrust knuckle bearing, the first thrust knuckle bearing is mounted on the short-side journal in an interference fit manner, and the second thrust knuckle bearing is mounted on the long-side journal in an interference fit manner; the bearing seat is in a straight cylinder shape, the first end of the bearing seat is provided with a flange edge extending outwards, the second end of the bearing seat is provided with an inner buckle, the first thrust knuckle bearing and the second thrust knuckle bearing are both installed in the bearing seat in an interference fit mode, and the inner buckle of the second end is buckled on an outer ring of the second thrust knuckle bearing; the long-side shaft neck extends out of the bearing seat through the inner buckle central channel; the end cover plate is fixed to the first end through a screw, and the end cover plate partially extends into the bearing seat cylinder to abut against the outer ring of the first thrust knuckle bearing.

Description

Technical Field

[0001] The present application belongs to the technical field of aircraft structure test loading, and in particular relates to a large-tonnage multi-degree-of-freedom joint. Background Art

[0002] In aircraft structure testing, the use of reasonable and advanced test equipment is the premise and guarantee for high-quality completion of the test. During the aircraft test, the structural test parts may be loaded in multiple directions, and deformation may occur in each direction. During the test, a hydraulic actuator is generally used for loading. The rear end of the actuator is fixed, and the front end is connected to the test piece through a connector. In order to ensure that only the load along the direction of the actuator is transmitted during the loading process, and no bending moment is transmitted ( Figure 1 As shown), while not limiting the deformation of the test piece. In the case of tension, the front end of the actuator and the test piece are generally loaded through a soft connection (such as a wire rope or a connector in series). In the case of compression, a movable seat at the front end of the actuator is generally used at the front end of the actuator. This movable seat has a 180° rotation angle in one direction and an 8° swing angle in the other direction. In the case of small deformation, these two methods can fully meet the test requirements, but if there is large structural deformation in multiple directions and there are large loads in both tension and compression, the movable seat at the front end of the actuator will not achieve the expected effect. Therefore, it is necessary to consider maximizing the rotation and swing freedom of the loading equipment to prevent the generation of additional bending moments caused by deformation, while achieving the purpose of protecting the test equipment and the test piece. Summary of the Invention

[0003] In order to solve the above problems, the present application provides a large-tonnage multi-degree-of-freedom joint, comprising:

[0004] The connecting shaft comprises a shaft body and shaft necks located on both axial sides of the shaft body, wherein the shaft neck has a diameter smaller than the shaft body and comprises a short side shaft neck and a long side shaft neck having a length greater than the short side shaft neck;

[0005] The first thrust spherical bearing and the second thrust spherical bearing are installed on the short side journal with an interference fit, and the second thrust spherical bearing is installed on the long side journal with an interference fit;

[0006] The bearing seat is straight-cylindrical, with an outward-facing flange at the first end and an inward-facing buckle at the second end. The first and second thrust spherical plain bearings are interference-fitted into the bearing seat, with the inward-facing buckle at the second end buckling onto the outer ring of the second thrust spherical plain bearing. The long-side journal extends out of the bearing seat through the inward-facing central channel.

[0007] The end cover is fixed on the first end by screws, and the end cover part extends into the bearing seat tube and abuts against the outer ring of the first thrust spherical bearing.

[0008] Preferably, the first thrust spherical bearing and the second thrust spherical bearing are installed opposite to each other.

[0009] Preferably, the long side journal has an adapter connected to the actuator.

[0010] Preferably, the bearing seat comprises two half-ring bearing seats separated along the neutral plane, the half-ring bearing seats are provided with connecting ears, and the butt bolts pass through the connecting ears to connect the two half-ring bearing seats.

[0011] Preferably, each half-ring bearing seat has an annular groove for accommodating the outer rings of the first thrust spherical plain bearing and the second thrust spherical plain bearing, so as to limit the axial displacement of the first thrust spherical plain bearing and the second thrust spherical plain bearing.

[0012] Preferably, the adapter is threadedly connected to the long-side shaft journal.

[0013] Preferably, a wrench operating surface is provided at a position where the long side journal is exposed from the bearing seat.

[0014] Preferably, the diameter of the shaft body is larger than the inner diameters of the first thrust spherical bearing and the second thrust spherical bearing but smaller than the outer diameters.

[0015] Advantages of this application include:

[0016] 1) Able to withstand large tonnage loads in both tension and compression;

[0017] 2) There is 360° rotational freedom along the axis and at least 15° of swing freedom in any radial direction.

[0018] 3) Ability to develop joints of various specifications according to the specifications of thrust spherical plain bearings. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the technical background of this application;

[0020] Figure 2 This is a diagram of the large-tonnage multi-degree-of-freedom joint of the present application in the coaxial state of the actuator and the bearing seat;

[0021] Figure 3 This is a diagram of the large-tonnage multi-degree-of-freedom joint in the present application when the actuator and the bearing seat are not in the same axis;

[0022] Figure 4 This is the structural diagram of the integral large-tonnage multi-degree-of-freedom joint of this application;

[0023] Figure 5 This is a structural diagram of a separate large-tonnage multi-degree-of-freedom joint in this application. DETAILED DESCRIPTION

[0024] To make the technical solution and its advantages of the present application clearer, the technical solution of the present application will be described in further detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only some embodiments of the present application and are only used to explain the present application, not to limit the present application. It should be noted that, for ease of description, only the parts related to the present application are shown in the accompanying drawings, and other related parts can refer to the general design. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments can be combined with each other to obtain new embodiments.

[0025] The main structure of the invention is divided into thrust spherical bearing, connecting shaft, bearing seat, end cover plate and adapter. Figure 2-Figure 4 ;

[0026] The thrust spherical plain bearing can be determined according to the load it can bear and the size of its inner hole. Two thrust spherical plain bearings of exactly the same model should be selected for installation.

[0027] The connecting shaft is designed as a stepped shaft, consisting of a central shaft section and two journal sections on either side. The shaft diameter should be larger than the inner diameter of the thrust spherical plain bearing but smaller than the outer diameter of the inner ring of the thrust spherical plain bearing. Its length is determined by the diameter of the selected hemisphere of the inner ring of the thrust spherical plain bearing. It must be ensured that the centers of the hemispheres completely overlap after the two bearings are installed relative to each other. The journal has a long side and a short side. The short side journal and the thrust spherical plain bearing are installed with an interference fit, and its length is consistent with the total height of the bearing. In addition to being consistent with the short side journal, the long side extends outward for a wrench operation flat, followed by an external thread for installing an adapter. The maximum outer diameter of the wrench operation flat and the threaded section cannot exceed the shaft journal diameter.

[0028] Bearing seats can be divided into two types: integral and split. The integral type has an annular main structure. The inner diameter of the main structure is determined by the outer diameter of the selected thrust spherical plain bearing. It is installed with an interference fit with the thrust spherical plain bearing. The inner diameter depth should not be less than the distance between the outermost ends of the two bearings after installation. The outer diameter is designed according to the load capacity. One end of the bearing seat is designed as an inward buckle to fix the outer ring of the thrust spherical plain bearing installed on the long end of the stepped shaft. The inner diameter of the inward buckle part should not limit the maximum swing angle of the thrust spherical plain bearing. The other end is designed with a docking flange for docking with the test piece. The center of the flange is sunken to a certain height, and the outer diameter is slightly larger than the inner diameter of the bearing seat. It is used to install the end cover and fix the outer ring of the thrust spherical plain bearing on the short side of the stepped shaft. The split bearing seat is a two-part semi-annular structure with similar main installation dimensions. The two parts are designed with docking ears along the radial direction at the docking point to achieve docking between the two parts and then fix the outer ring of the bearing.

[0029] The end cover is mainly used to axially fix the bearing at the short side of the stepped shaft. The structure must achieve axial tightening of the bearing. It is assembled with the bearing seat through a flange-like structure and is flush with the surface of the bearing seat flange after assembly.

[0030] The adapter is threaded both inside and outside. The internal thread connects to the long side thread of the stepped shaft, and the external thread connects to the loading actuator or force sensor.

[0031] Reference Attachment Figure 4 , an embodiment of the present application includes: (1) an integral structure

[0032] The overall structure diagram is as follows Figure 3 As shown, it mainly includes screws 1, end cover 2, bearing seat 3, thrust spherical plain bearings 4 and 5, connecting shaft 6, and adapter 7. The inner rings of thrust spherical plain bearings 4 and 5 are installed relative to each other. The thrust spherical plain bearing 4 is installed on the short side journal of the connecting shaft 6 by interference fit, and the thrust spherical plain bearing 5 is installed on the long side journal of the connecting shaft 6 by interference fit, and the inner rings are both close to the shaft shoulder. Then, it is installed on the bearing seat 3 by interference fit, with the short side of the connecting shaft 6 facing the flange of the bearing seat 3. The outer ring of the thrust spherical plain bearing 5 is fixed by the inner buckle part of the bearing seat 3 to achieve axial fixation of the thrust spherical plain bearing 5. The end cover 2 is connected to the flange of the bearing seat 3 by screw 1. The inner ring of the end cover 2 is close to the outer ring of the thrust spherical plain bearing 4 to achieve axial fixation of the thrust spherical plain bearing 4. The adapter 7 is installed on the external threaded part of the long side of the connecting shaft by thread.

[0033] Reference Attachment Figure 5 An embodiment of the present application includes: (2) a separate structure, which mainly includes a screw 1, an end cover plate 2, a half-ring bearing seat 8, thrust spherical bearings 4 and 5, a connecting shaft 6, an adapter 7, and a docking bolt 9. The inner rings of the thrust spherical bearings 4 and 5 are installed relative to each other, the thrust spherical bearing 4 is installed on the short side journal of the connecting shaft 6 by interference fit, and the thrust spherical bearing 5 is installed on the long side journal of the connecting shaft 6 by interference fit, and the inner rings are both close to the shaft shoulders, the two semi-ring bearing seats 8 are enclosed in the outside of the thrust spherical bearings 4 and 5, and are docked by docking bolts 9 through the docking ears on the semi-ring bearing seats 8, the short side of the connecting shaft 6 is facing the flange of the bearing seat 3, and the outer ring of the thrust spherical bearing 5 is fixed by the buckled part of the semi-ring bearing seat 8 to achieve axial fixation of the thrust spherical bearing 5, the end cover plate 2 is docked with the flange of the bearing seat 3 by the screw 1, the inner ring of the end cover plate 2 is close to the outer ring of the thrust spherical bearing 4, to achieve axial fixation of the thrust spherical bearing 4, and the adapter 7 is installed on the external threaded part of the long side of the connecting shaft by thread.

[0034] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A large-tonnage multi-degree-of-freedom joint, characterized in that: include: A connecting shaft (6) includes a shaft body and shaft necks located on both axial sides of the shaft body, wherein the shaft neck has a diameter smaller than the shaft body and includes a short side shaft neck and a long side shaft neck having a length greater than the short side shaft neck; A first thrust spherical bearing (4) and a second thrust spherical bearing (5), wherein the first thrust spherical bearing (4) is installed on the short side journal with an interference fit, and the second thrust spherical bearing (5) is installed on the long side journal with an interference fit; The bearing seat (3) is in the shape of a straight cylinder, with an outward-extending flange at the first end and an inward-facing buckle at the second end. The first thrust spherical bearing (4) and the second thrust spherical bearing (5) are both installed in the bearing seat (3) with an interference fit, and the inward-facing buckle at the second end is buckled on the outer ring of the second thrust spherical bearing (5); the long side journal extends out of the bearing seat (3) through the inward-facing central channel; The end cover plate (2) is fixed to the first end by means of screws (1), and a portion of the end cover plate (2) extends into the cylinder of the bearing seat (3) and abuts against the outer ring of the first thrust spherical bearing (4).

2. The large-tonnage multi-degree-of-freedom joint according to claim 1, characterized in that: The first thrust spherical bearing (4) and the second thrust spherical bearing (5) are installed relative to each other.

3. The large-tonnage multi-degree-of-freedom joint according to claim 1, characterized in that: The long side journal is provided with an adapter (7) connected with the actuator.

4. The large-tonnage multi-degree-of-freedom joint according to claim 1, characterized in that: The bearing seat (3) comprises two half-ring bearing seats (8) separated along a neutral plane. The half-ring bearing seats (8) are provided with connecting lugs. Butt bolts (9) pass through the connecting lugs to connect the two half-ring bearing seats (8).

5. The large-tonnage multi-degree-of-freedom joint according to claim 4, characterized in that: Each half-ring bearing seat (8) has an annular groove for accommodating the outer rings of the first thrust spherical bearing (4) and the second thrust spherical bearing (5), and is used to limit the axial displacement of the first thrust spherical bearing (4) and the second thrust spherical bearing (5).

6. The large-tonnage multi-degree-of-freedom joint according to claim 3, characterized in that: The adapter (7) is threadedly connected to the long side journal.

7. The large-tonnage multi-degree-of-freedom joint according to claim 3, characterized in that: A wrench operating plane is provided at a position where the long side journal is exposed from the bearing seat (3).

8. The large-tonnage multi-degree-of-freedom joint according to claim 3, characterized in that: The diameter of the shaft body is larger than the inner diameters of the first thrust spherical bearing (4) and the second thrust spherical bearing (5) but smaller than the outer diameter.

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