Sliding type auxiliary clamp capable of releasing constraint degree of freedom

Abstract

The invention provides a sliding type auxiliary clamp capable of releasing constraint degree of freedom, which comprises a guide rail, a connecting rod and a ball bearing group, and the ball bearing group is positioned on the inner side of the guide rail and is connected with a sample to be tested; a plurality of ball bearing groups can be arranged on the inner sides of the guide rails; a connecting rod is arranged on one side of the guide rail and connected with an external stretching device. According to the sliding type auxiliary clamp capable of releasing the constraint freedom degree, the structural design is simple, the manufacturing cost is low, and the economic applicability is improved.

Description

Technical Field

[0001] The invention relates to the technical field of auxiliary clamps, and in particular to a sliding auxiliary clamp capable of releasing a constrained degree of freedom. Background Art

[0002] In the field of material mechanical properties testing, the design of the fixture is crucial to the accuracy and reliability of the experiment. Traditional fixtures usually adopt a fixed design to firmly clamp the specimen in a certain position for tensile or compression testing. However, this fixed fixture has limitations in some special tests. For example, the two ends of the specimen are fixed, which limits the deformation of the ends, resulting in stress concentration at the ends of the specimen clamping, while the deformation is concentrated in the middle part of the specimen, so that the overall uniform deformation of the specimen cannot be observed, and some important deformation features may be ignored. In order to overcome the above-mentioned shortcomings of traditional fixtures, it is of great significance to develop a new type of fixture that allows the ends of the specimen to move freely while maintaining sufficient clamping force to improve the accuracy and applicability of material testing. This fixture can not only help researchers better understand the overall behavior of materials and structures, but also may reveal important characteristics that are overlooked under traditional testing methods. Summary of the invention

[0003] The purpose of the present invention is to provide a sliding auxiliary clamp capable of releasing the constraint degree of freedom, which has a simple structural design, low manufacturing cost and improved economic applicability.

[0004] To achieve the above object, the present invention provides a sliding auxiliary fixture capable of releasing the constraint degree of freedom, comprising a guide rail, a connecting rod and a ball bearing group.

[0005] The ball bearing group is located inside the guide rail and connected to the sample to be tested; multiple groups of ball bearing groups can be arranged inside the guide rail;

[0006] A connecting rod is provided on one side of the guide rail, and the connecting rod is connected to an external stretching device.

[0007] Preferably, a transmission shaft is provided on the ball bearing group, a first bearing and a second bearing are sleeved on the transmission shaft, a sample to be tested is clamped between the first bearing and the second bearing, and rings are provided on the outer sides of the first bearing and the second bearing.

[0008] Preferably, the guide rail has a C-shaped cross-section, and is specifically provided with a first connecting plate, a first rib plate and a second rib plate are respectively provided on both sides of the first connecting plate, and a first side wing and a second side wing are respectively provided on the other sides of the first rib plate and the second rib plate.

[0009] Preferably, a distance is provided between the first side wing and the second side wing, the distance being greater than the diameter of the ball bearing, the major axis direction of the guide rail cross section is parallel to the transmission shaft, and the width of the first side wing and the second side wing is slightly greater than the thickness of the roller bearing.

[0010] Preferably, the transmission shaft passes through the sample to be tested, and gaps are provided between the two ends of the transmission shaft and the first rib plate and the second rib plate, so that they are not in direct contact.

[0011] Preferably, the ferrule material has a low elastic modulus, is usually an elastomer, and has an interference fit with the transmission shaft.

[0012] Preferably, the guide rails are symmetrically distributed at both ends of the sample to be tested, and the ball bearing groups are arranged in a matrix and stacked with the central axis of the segmented portion of the sample.

[0013] Preferably, the guide rails may be provided in multiple groups in different directions of the sample to be tested.

[0014] Preferably, a connecting piece may be further provided between the connecting rod and the first connecting plate, and the shapes of the connecting piece and the connecting rod may be changed according to the setting of the external stretching device.

[0015] Therefore, the present invention adopts the above-mentioned sliding auxiliary clamp that can release the constraint freedom. By introducing a sliding guide rail in the clamp design, the ball bearing and the sample are connected and clamped in multiple sections, and the axial constraint freedom along the guide rail direction can be released during the tensile and compression tests of the sample, so that the sample can slide freely within a certain range when a tensile or compressive force is applied. This sliding auxiliary clamp avoids the unnecessary boundary stress introduced by the traditional fixed clamp, allows the entire sample structure to deform uniformly, and can observe some deformation modes that cannot be seen under the fixed clamp, which is helpful for in-depth research on the mechanical properties of materials and structures. In addition, this auxiliary clamp has a simple structural design and a low manufacturing cost, which improves economic applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of the connection between a sliding auxiliary fixture capable of releasing the constraint degree of freedom and a lattice material assembly proposed by the present invention;

[0017] Figure 2 The right side schematic diagram of the assembly of a sliding auxiliary fixture capable of releasing the constraint degree of freedom and a lattice material proposed by the present invention;

[0018] Figure 3 A schematic diagram of a sliding guide structure of a sliding auxiliary fixture capable of releasing a constraint degree of freedom proposed by the present invention;

[0019] Figure 4A front view of a sliding guide rail structure of a sliding auxiliary fixture capable of releasing a constraint degree of freedom proposed by the present invention;

[0020] Figure 5 It is a right side view of a sliding guide rail structure of a sliding auxiliary fixture capable of releasing the constraint degree of freedom proposed by the present invention;

[0021] Figure 6 A schematic diagram of the structure of a ball bearing group of a sliding auxiliary fixture capable of releasing a constraint degree of freedom proposed by the present invention;

[0022] Figure 7 A front view of a ball bearing group structure of a sliding auxiliary fixture capable of releasing a constraint degree of freedom proposed by the present invention;

[0023] Figure 8 This is a right side view of the ball bearing group structure of a sliding auxiliary fixture capable of releasing the constraint freedom proposed by the present invention.

[0024] Reference numerals

[0025] 1. Guide rail; 11. Connecting plate; 12. First rib; 13. First wing; 14. Second rib; 15. Second wing; 16. First connecting plate; 2. Ball bearing assembly; 21. Transmission shaft; 22. Ring; 23. First bearing; 24. Second bearing; 3. Sample to be tested; 4. Connecting rod. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0027] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0028] Embodiment 1

[0029] The present invention provides a sliding auxiliary clamp capable of releasing a constraint degree of freedom, comprising a guide rail 1, a connecting rod 4 and a ball bearing group 2.

[0030] A transmission shaft 21 is provided on the ball bearing group 2. The transmission shaft 21 passes through the sample 3 to be tested. A first bearing 23 and a second bearing 24 are sleeved on the transmission shaft 21. The sample 3 to be tested is clamped between the first bearing 23 and the second bearing 24. Rings 22 are provided on the outer sides of the first bearing 23 and the second bearing 24. The rings 22 are used to fix the positions of the first bearing 23 and the second bearing 24 on the transmission shaft 21. The elastic modulus of the material of the rings 22 is low, and it is usually an elastomer, and it has an interference fit with the transmission shaft 21.

[0031] The ball bearing group 2 is located on the inner side of the guide rail 1 , and the ball bearing group 2 slides on the inner side of the guide rail 1 ; multiple groups of ball bearing groups 2 can be arranged on the inner side of the guide rail 1 , and are arranged according to the size of the sample 3 to be tested.

[0032] The two sides of the sample 3 to be tested connected to the guide rail 1 need to be designed in sections, each section is tightly connected to the transmission shaft 21, and multiple sets of slidable ball bearing groups 2 are installed at different positions to achieve uniform force on different parts of the sample 3 to be tested.

[0033] There are multiple groups of ball bearings 2, each group is connected to the end section of the sample 3. At the same time, the sample 3 is supported to contact the upper and lower inner walls of the guide rail 1 and slide in the guide rail 1 to release the degree of freedom along the guide rail 1.

[0034] A connecting rod 4 is provided on one side of the guide rail 1, and the connecting rod 4 is connected to the external stretching device. A connecting piece 11 may also be provided between the connecting rod 4 and the first connecting plate 16, and the shapes of the connecting piece 11 and the connecting rod 4 are changed according to the setting of the external stretching device. The connecting piece 11 provided in this embodiment is wedge-shaped.

[0035] The guide rail 1 has a C-shaped cross-section, and is specifically provided with a first connecting plate 16. The first ribs 12 and the second ribs 14 are respectively provided on both sides of the first connecting plate 16. The first side wings 13 and the second side wings 15 are respectively provided on the other sides of the first ribs 12 and the second ribs 14. The first connecting plate 16 and the first ribs 12 and the second ribs 14 provided on both sides, and the first side wings 13 and the second side wings 15 provided on one side of the first ribs 12 and the second ribs 14 form a cavity, and the ball bearing group 2 is located in this cavity. The first bearing 23 and the second bearing 24 contact with the inner wall of the guide rail 1 and slide under the action of tension and compression. The sliding process should be ensured to be smooth and the friction between the contact surfaces should be reduced as much as possible. Lubricating oil can be applied to the inner wall of the guide rail 1 to eliminate additional friction or stress during the sliding process.

[0036] There is a distance between the first wing 13 and the second wing 15, which is greater than the diameters of the first bearing 23 and the second bearing 24. The long axis direction of the cross section of the guide rail 1 is parallel to the transmission shaft 21, and the width of the first wing 13 and the second wing 15 is slightly greater than the thickness of the roller bearing.

[0037] The transmission shaft 21 passes through the sample 3 to be tested, and gaps are provided between the two ends of the transmission shaft 21 and the first rib 12 and the second rib 14 so as not to be in direct contact with each other.

[0038] The material of the ferrule 22 has a low elastic modulus and is usually an elastomer, and has an interference fit with the transmission shaft 21 .

[0039] The guide rails 1 are symmetrically distributed at both ends of the sample 3 to be tested, and the ball bearing groups 2 are arranged in a matrix and stacked with the central axis of the segmented parts of the sample 3 to be tested. During the compression process of the sample 3 to be tested, the symmetrically distributed double-row first bearings 23 and second bearings 24 contact the inner wall of the sliding guide rail 1 to avoid the eccentric effect.

[0040] The guide rails 1 may also be arranged in multiple groups in different directions of the sample 3 to be tested, and the above conditions can be met as long as the number of the guide rails 1 is double. In this embodiment, two symmetrical groups of guide rails 1 are arranged.

[0041] from Figure 2 As can be seen from the schematic diagram on the right side of the structure, the sample 3 to be tested is not directly connected to the fixture, but is connected to the inner wall of the guide rail 1 through the ball bearing group 2 fixed on the sample 3 to be tested. Through the contact between the roller bearing group 2 and the inner wall of the first side wing 13 and the second side wing 15, the auxiliary fixture can perform both tensile tests and compression tests. This auxiliary fixture avoids the defect that the traditional fixture tightly clamps the sample 3 to be tested, resulting in the end of the sample 3 to be tested being unable to deform. By sliding the ball bearing group 2 on the smooth guide rail 1 to release the degree of freedom along the guide rail 1, the deformation of the structure can be uniform within the overall range.

[0042] Figure 6 The figure is a schematic diagram of the connection part between the ball bearing group and the experimental sample. The sample 3 to be tested and the first bearing 23 and the second bearing 24 are connected through the transmission shaft 21, and the ring 22 is used to fix the position of the bearing. Four bearings are set on each side of the end of the sample 3 to be tested, and the ball bearings are arranged orthogonally. It should be noted that the relative position between the bearings needs to be considered in combination with the bearing radius and the cross-sectional dimensions of the end of the sample to be tested. The lateral and longitudinal spacing of each transmission shaft 21 needs to be slightly larger than the diameter of the roller bearing. Secondly, the maximum distance between the upper and lower double-row ball bearings needs to be less than the height of the first rib 12 and the second rib 14. Thirdly, the distance between the upper row of transmission shafts and the edge of the sample should be less than the maximum radius of the roller bearing to ensure smooth contact between the bearing and the inner wall of the guide rail 1. Figure 7 and Figure 8 The front view and right side view of the connection between the ball bearing group 2 and the sample 3 to be tested are shown to illustrate the position of the bearing on the sample 3 to be tested. The bearing can be installed on the sample 3 to be tested by assembling suitable standard parts, but the shaft hole for arranging the transmission shaft 21 on the sample 3 to be tested needs to be designed in advance, and a certain assembly error needs to be considered.

[0043] Therefore, the present invention adopts the above-mentioned sliding auxiliary clamp capable of releasing the constrained degree of freedom, which has a simple structural design and a low manufacturing cost, thereby improving economic applicability.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A sliding auxiliary fixture capable of releasing the constraint degree of freedom, characterized in that: Including guide rails, connecting rods and ball bearing sets, The ball bearing group is located inside the guide rail and connected to the sample to be tested; multiple groups of ball bearing groups can be arranged inside the guide rail; A connecting rod is provided on one side of the guide rail, and the connecting rod is connected to an external stretching device.

2. A sliding auxiliary fixture capable of releasing the constraint degree of freedom according to claim 1, characterized in that: The ball bearing group is provided with a transmission shaft, and the transmission shaft is sleeved with a first bearing and a second bearing. The sample to be tested is clamped between the first bearing and the second bearing, and rings are provided on the outer sides of the first bearing and the second bearing.

3. A sliding auxiliary fixture capable of releasing the constraint degree of freedom according to claim 1, characterized in that: The guide rail has a C-shaped cross-section and is specifically provided with a first connecting plate. The first connecting plate is provided with a first rib plate and a second rib plate on both sides thereof. The first rib plate and the second rib plate are provided with a first side wing and a second side wing on the other sides thereof.

4. A sliding auxiliary fixture capable of releasing the constraint degree of freedom according to claim 3, characterized in that: A distance is set between the first side wing and the second side wing, which is greater than the diameter of the ball bearing. The long axis direction of the guide rail cross section is parallel to the transmission shaft. The width of the first side wing and the second side wing is slightly greater than the thickness of the roller bearing.

5. The sliding auxiliary clamp capable of releasing the constraint degree of freedom according to claim 2, characterized in that: The transmission shaft passes through the sample to be tested, and gaps are provided between the two ends of the transmission shaft and the first rib plate and the second rib plate, so that they are not in direct contact.

6. A sliding auxiliary fixture capable of releasing the constraint degree of freedom according to claim 2, characterized in that: The elastic modulus of the ring material is relatively low, and the ring is usually an elastomer, and has an interference fit with the transmission shaft.

7. A sliding auxiliary fixture capable of releasing the constraint degree of freedom according to claim 1, characterized in that: The guide rails are symmetrically distributed at both ends of the sample to be tested, and the ball bearing groups are arranged in a matrix and stacked with the central axis of the segmented parts of the sample.

8. The sliding auxiliary fixture capable of releasing the constraint degree of freedom according to claim 1, characterized in that: The guide rails can also be arranged in multiple groups in different directions of the sample to be tested.

9. The sliding auxiliary clamp capable of releasing the constraint degree of freedom according to claim 1, characterized in that: A connecting piece may be further provided between the connecting rod and the first connecting plate, and the shapes of the connecting piece and the connecting rod may be changed according to the setting of the external stretching device.

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