Metal material detection equipment and detection clamp thereof

Abstract

The invention relates to the technical field of detection devices, in particular to metal material detection equipment and a detection clamp thereof. The detection clamp comprises two clamping mechanisms. Each clamping mechanism comprises two clamping assemblies, each clamping assembly comprises a clamping block and a flexible interlayer, and a pressing needle is arranged on each clamping block. When a workpiece is clamped, the pressing needle firstly makes contact with the workpiece, the pressing needle presses a pit in the workpiece, and therefore the friction force is increased through clamping. After the pressing needle presses the concave pit on the workpiece, the flexible interlayer is pushed to make contact with the workpiece, the friction force is further improved, when the pressing needle presses the concave pit on the workpiece, the flexible interlayer provides certain reverse thrust, and the situation that the concave pit pressed on the workpiece is too deep, and consequently the workpiece is damaged is prevented. The invention provides detection equipment for a metal material and a detection clamp thereof, and aims to solve the problem that when a workpiece is clamped by an existing detection device, a bulge for improving friction on the clamp is easy to generate an over-deep pit on the workpiece, so that the workpiece is damaged.

Description

Technical Field

[0001] The present invention relates to the technical field of detection devices, and particularly relates to a detection device for metal materials and a detection fixture thereof. Background Art

[0002] Metal material detection devices are widely used in multiple fields such as manufacturing, construction, aerospace, and automobile manufacturing. For example, in the manufacturing industry, by detecting the chemical composition, mechanical properties, etc. of metal materials, the quality stability of products can be ensured; in the aerospace field, non-destructive testing of metal materials is particularly important to ensure the safety and reliability of aircraft. The evolution of metal detection devices is essentially the result of cross-innovation of materials science, electronic technology, and computer science, and its development continuously promotes the upgrading of the manufacturing industry and the improvement of industrial safety levels.

[0003] By means of tensile tests, compression tests, bending tests, etc., the behavior of metal materials under stress conditions is evaluated, including indicators such as strength, hardness, and toughness. These tests are of great significance for evaluating the bearing capacity and plastic deformation ability of metal materials. These indicators need to be measured by a tensile testing machine, and the fixture is one of the key parts on the tensile testing machine.

[0004] For example, the utility model patent with the publication number CN202177546U provides a tensile fixture. The wedge-shaped tooth block can provide a reliable clamping force during the tensile process. The plug pin and the pin hole play a dual role of positioning during the installation of the specimen and providing tensile stress to make up for the insufficient clamping force during the tensile loading. However, this fixture is provided with patterns on the clamping surface of the wedge-shaped tooth block to make the metal clamping surface deformed during clamping so as to be clamped to increase the friction force. However, when the hardness of the metal material is relatively large, the clamping force is too small and it is easy for the workpiece and the fixture to come apart; when the hardness of the metal material is relatively small, it is easy to produce too deep pits, thereby damaging the workpiece and causing the workpiece to break at the clamping part with the fixture. Summary of the Invention

[0005] The present invention provides a detection device for metal materials and a detection fixture thereof to solve the problem that when the existing detection device clamps a workpiece, the protrusions for increasing friction on the fixture are likely to produce too deep pits on the workpiece, thereby damaging the workpiece.

[0006] A detection fixture of the present invention adopts the following technical solution: A detection fixture includes a bracket and two clamping mechanisms. The clamping mechanisms are arranged on the bracket, the two clamping mechanisms are distributed in sequence along the up-and-down direction, and the two clamping mechanisms can move relatively along the vertical direction.

[0007] Each clamping mechanism includes a housing and two clamping components. The two clamping components are sequentially distributed along the horizontal direction, and the direction in which the two clamping components are sequentially distributed is the first direction. The two clamping components move closer to each other to clamp the workpiece. Each clamping component includes a clamping block, a core, a flexible interlayer, and a driving unit. The clamping block is slidably disposed in the housing. Along the first direction, an installation groove is formed on one side of the clamping block close to the adjacent clamping block. A plurality of pressing needles are fixedly arranged in the installation groove. The pressing needles are horizontally arranged and are used to abut against the workpiece.

[0008] The core is horizontally slidably disposed in the installation groove, and the driving unit is used to drive the core to slide horizontally. A plurality of first needle holes are formed in the core. The flexible interlayer is fixedly arranged on the side of the core close to the workpiece. A plurality of second needle holes are formed in the flexible interlayer. Each pressing needle sequentially passes through a first needle hole and a second needle hole. The flexible interlayer is used to abut against the workpiece.

[0009] Further, hydraulic chambers are respectively formed on both sides of each clamping block along the second direction. The second direction is the horizontal direction and is perpendicular to the first direction. The two hydraulic chambers communicate with the installation groove. Hydraulic wing plates are respectively fixedly arranged on both sides of each core along the second direction. The hydraulic wing plates are vertically arranged, and each hydraulic wing plate is slidably disposed in a hydraulic chamber. Hydraulic oil is arranged in the hydraulic chamber. Two hydraulic ports are formed in each clamping block, and each hydraulic port communicates with the hydraulic chamber. The driving unit includes a first hydraulic cylinder. The first hydraulic cylinder is fixedly arranged on the bracket, and two hydraulic oil pipes are arranged on the first hydraulic cylinder. Each hydraulic oil pipe communicates with a hydraulic port.

[0010] Further, the two sides of the clamping block along the up-and-down direction are respectively the first side and the second side, and the side of the clamping block close to the clamping block in the adjacent clamping mechanism is the first side. The installation groove is sequentially divided into a first part, a second part, and a third part along the direction from the second side to the first side of the clamping block. Among the plurality of pressing needles in the third part of the installation groove, along the direction from the second side to the first side, the lengths of the pressing needles gradually decrease.

[0011] Further, a first inclined surface is formed on the side of the clamping block away from the workpiece along the first direction. Along the direction from the second side to the first side of the clamping block, the first inclined surface gradually approaches the workpiece. Two second inclined surfaces are formed on the housing. The two second inclined surfaces are sequentially distributed along the horizontal direction. Each second inclined surface abuts against a first inclined surface, and each second inclined surface is parallel to the first inclined surface with which it abuts.

[0012] Further, the bracket includes a base and a gantry. The gantry is fixedly arranged on the base, and a lifting platform capable of sliding up and down is arranged on the gantry. The housing of the clamping mechanism on the upper side is arranged on the lifting platform. The housing of the clamping mechanism on the lower side is fixedly arranged on the base.

[0013] Further, each clamping mechanism further includes a driving component, and the driving component includes a second hydraulic cylinder and a pressure plate. The second hydraulic cylinder is vertically arranged, and the upper end of the second hydraulic cylinder is fixedly connected to the housing. The pressure plate is fixedly arranged at the lower end of the second hydraulic cylinder. A co-location platform is fixedly arranged on the second side of the clamping block, and a semi-circular groove is formed in the co-location platform. Each pressure plate is arranged in two semi-circular grooves within one clamping mechanism.

[0014] Further, a third hydraulic cylinder is fixedly arranged on the gantry, the extending end of the third hydraulic cylinder is vertically arranged, and is fixedly connected to the lifting platform.

[0015] Further, two limiting components are arranged on each housing, the two limiting components are sequentially distributed along the first direction, each limiting component includes two limiting plates, the two limiting plates are sequentially distributed along the second direction, the limiting plates are detachable, and each clamping block is located between the two limiting plates within one limiting component.

[0016] Further, guide rails are arranged on both sides of each clamping block along the second direction, the guide rails are inclined, and each guide rail is parallel to the first inclined surface on the corresponding clamping block. A sliding groove is arranged on each limiting plate, the sliding groove is inclined, and each guide rail is slidably arranged in one sliding groove.

[0017] Further, a detection device for a metal material includes the above-mentioned detection fixture, and further includes a tensile force detector. The tensile force detector is fixedly arranged on the lifting platform, and is fixedly connected to the housing on the lifting platform. The tensile force detector is used to detect the tensile force applied to the workpiece.

[0018] The beneficial effects of the present invention are as follows: For a detection fixture of the present invention, by arranging the clamping mechanism, the workpiece is placed between the two clamping components, and the clamping components are moved to make the two clamping components in each clamping mechanism approach each other. The pressing needles on each clamping block first contact the workpiece, and the pressing needles press pits on the workpiece, so as to be clamped to increase the friction force. While the pressing needles press pits on the workpiece, the flexible interlayer is pushed by the driving unit, so that the flexible interlayer contacts the workpiece, and the flexible interlayer fills the part where the pressing needles do not contact the workpiece, further increasing the friction force, and the friction forces of the two clamping methods are superimposed on each other, which can provide more friction force when clamping the workpiece and prevent the clamping block from separating from the workpiece. In addition, when the pressing needles press pits on the workpiece, the flexible interlayer provides a certain reaction force to prevent the pits pressed on the workpiece from being too deep, thereby damaging the workpiece. Description of the Drawings

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0020] Figure 1 A schematic diagram of the structure of a detection fixture provided by an embodiment of the present invention; Figure 2 A schematic structural diagram of a clamping mechanism of a detection fixture provided by an embodiment of the present invention; Figure 3 A partial cross-sectional view of a clamping mechanism of a detection fixture provided by an embodiment of the present invention; Figure 4 A partial structural schematic diagram of a clamping assembly of a detection fixture provided by an embodiment of the present invention; Figure 5 A partial structural cross-sectional view of a clamping assembly of a detection fixture provided by an embodiment of the present invention; Figure 6 A cross-sectional view from another perspective of a clamping assembly of a detection fixture provided by an embodiment of the present invention; Figure 7 A schematic structural diagram of a core and a flexible interlayer of a detection fixture provided in an embodiment of the present invention.

[0021] In the figure: 100, bracket; 200, tension detector; 300, lifting platform; 400, shell; 410, limit plate; 430, second hydraulic cylinder; 431, pressure plate; 440, clamping block; 441, guide rail; 442, hydraulic cavity; 443, hydraulic port; 444, pressure needle; 445, first inclined surface; 450, sandwich core; 451, flexible interlayer; 452, hydraulic wing plate; 453, first pinhole; 460, same position platform. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] Reference Figures 1 to 7 As shown, an inspection fixture provided by an embodiment of the present invention includes a bracket 100 and two clamping mechanisms. The clamping mechanisms are arranged on the bracket 100, and the two clamping mechanisms are sequentially distributed along the up-down direction, and the two clamping mechanisms can move relative to each other along the vertical direction.

[0024] Each clamping mechanism includes a housing 400 and two clamping components. The two clamping components are sequentially distributed along the horizontal direction, and the direction in which the two clamping components are sequentially distributed is the first direction. The two clamping components move closer to each other to clamp the workpiece. Each clamping component includes a clamping block 440, a clamping core 450, a flexible interlayer 451, and a driving unit. The clamping block 440 is slidably disposed in the housing 400. Along the first direction, on one side of the clamping block 440 adjacent to the adjacent clamping block 440, a mounting groove is formed. A plurality of press pins 444 are fixedly disposed in the mounting groove. The press pins 444 are horizontally arranged and are used to abut against the workpiece.

[0025] The clamping core 450 is horizontally slidably disposed in the mounting groove, and the driving unit is used to drive the clamping core 450 to slide horizontally. A plurality of first pin holes 453 are formed in the clamping core 450. The flexible interlayer 451 is fixedly disposed on the side of the clamping core 450 close to the workpiece. A plurality of second pin holes are formed in the flexible interlayer 451. Each press pin 444 sequentially passes through a first pin hole 453 and a second pin hole. The flexible interlayer 451 is used to abut against the workpiece.

[0026] Place the workpiece between the two clamping components and move the clamping components so that the two clamping components in each clamping mechanism move closer to each other. The press pins 444 on each clamping block 440 first contact the workpiece, and the press pins 444 press pits on the workpiece, thereby achieving a snap fit to increase the friction force. While the press pins 444 press pits on the workpiece, the flexible interlayer 451 is pushed by the driving unit so that the flexible interlayer 451 contacts the workpiece. The flexible interlayer 451 fills the part where the press pins 444 do not contact the workpiece, further increasing the friction force. Moreover, the friction forces of the two clamping methods are superimposed on each other, providing more friction force when clamping the workpiece and preventing the clamping block 440 from separating from the workpiece. In addition, when the press pins 444 press pits on the workpiece, the flexible interlayer 451 provides a certain reaction force to prevent the pits pressed on the workpiece from being too deep and thus damaging the workpiece.

[0027] In this embodiment, on both sides of each clamping block 440 along the second direction, hydraulic chambers 442 are respectively formed. The second direction is the horizontal direction and is perpendicular to the first direction. The two hydraulic chambers 442 communicate with the mounting groove. On both sides of each clamping core 450 along the second direction, hydraulic wing plates 452 are respectively fixedly disposed. The hydraulic wing plates 452 are vertically arranged, and each hydraulic wing plate 452 is slidably disposed in a hydraulic chamber 442. Hydraulic oil is provided in the hydraulic chamber 442. Two hydraulic ports 443 are formed in each clamping block 440, and each hydraulic port 443 communicates with the hydraulic chamber 442. The driving unit includes a first hydraulic cylinder. The first hydraulic cylinder is fixedly disposed on the bracket 100, and two hydraulic oil pipes are provided on the first hydraulic cylinder. Each hydraulic oil pipe communicates with a hydraulic port 443.

[0028] The diameter and density of the first pinhole 453 are the same as those of the pressing pin 444. The cooperation between the pressing pin 444 and the first pinhole 453 prevents the hydraulic oil from leaking out. In addition, the flexible sandwich layer 451 is a flexible layer, and its material can be wear-resistant rubber. The diameter of the second pinhole is the same as that of the pressing pin 444, which further prevents the hydraulic oil in the hydraulic chamber 442 from leaking out.

[0029] In this embodiment, the two sides of the clamping block 440 along the up-and-down direction are respectively the first side and the second side. The side of the clamping block 440 close to the clamping block 440 in the adjacent clamping mechanism is the first side, and the side of the clamping block 440 far from the clamping block 440 in the adjacent clamping mechanism is the second side. The installation groove is sequentially divided into a first part, a second part, and a third part along the direction from the second side to the first side of the clamping block 440. Among them, for the multiple pressing pins 444 in the third part of the installation groove, along the direction from the second side to the first side, the length of the pressing pin 444 gradually decreases.

[0030] When the clamping block 440 clamps the workpiece, the closer to the first side of the clamping block 440, the greater the reaction force of the pressing pin 444 received by the workpiece. Therefore, when the workpiece contacts the pressing pins 444 in the third part, it is easy to break here. Therefore, by gradually reducing the length of the multiple pressing pins 444 in the third part along the direction from the second side to the first side, the workpiece is prevented from breaking at the clamping position.

[0031] In this embodiment, on the side of the clamping block 440 away from the workpiece along the first direction, a first inclined surface 445 is provided. Along the direction from the second side to the first side of the clamping block 440, the first inclined surface 445 gradually approaches the workpiece. Two second inclined surfaces are provided on the housing 400. The two second inclined surfaces are sequentially distributed along the horizontal direction. Each second inclined surface abuts against a first inclined surface 445, and each second inclined surface is arranged in parallel with the first inclined surface 445 against which it abuts.

[0032] When the clamping block 440 moves along the direction from the second side to the first side of the clamping block 440, under the action of the first inclined surface 445 and the second inclined surface, the two clamping blocks 440 approach each other.

[0033] In this embodiment, the bracket 100 includes a base and a gantry. The gantry is fixedly arranged on the base, and a lifting platform 300 capable of sliding up and down is arranged on the gantry. The housing 400 of the clamping mechanism on the upper side is arranged on the lifting platform 300. The housing 400 of the clamping mechanism on the lower side is fixedly arranged on the base.

[0034] In this embodiment, each clamping mechanism further includes a driving component, and the driving component includes a second hydraulic cylinder 430 and a pressure plate 431. The second hydraulic cylinder 430 is vertically arranged, and the upper end of the second hydraulic cylinder 430 is fixedly connected to the housing 400. The pressure plate 431 is fixedly arranged at the lower end of the second hydraulic cylinder 430. A co-positioning platform 460 is fixedly arranged on the second side of the clamping block 440, and a semi-circular groove is formed in the co-positioning platform 460. Each pressure plate 431 is arranged in the two semi-circular grooves within one clamping mechanism.

[0035] Start the second hydraulic cylinder 430. The second hydraulic cylinder 430 extends, thereby pushing the pressure plate 431 to move. The pressure plate 431 drives the clamping block 440 to move through the co-positioning platform 460, and the clamping block 440 moves along the direction from the second side to the first side of the clamping block 440.

[0036] In this embodiment, a third hydraulic cylinder is fixedly arranged on the gantry. The extending end of the third hydraulic cylinder is vertically arranged and is fixedly connected to the lifting platform 300. Start the third hydraulic cylinder to move the lifting platform 300 up and down.

[0037] In this embodiment, two limiting components are arranged on each housing 400. The two limiting components are sequentially distributed along the first direction. Each limiting component includes two limiting plates 410, and the two limiting plates 410 are sequentially distributed along the second direction. The second direction is the horizontal direction, and the second direction is perpendicular to the first direction. The limiting plates 410 are detachable, and each clamping block 440 is located between the two limiting plates 410 within one limiting component. The limiting plates 410 are used to limit the movement of the clamping block 440 along the second direction.

[0038] In this embodiment, guide rails 441 are arranged on both sides of each clamping block 440 along the second direction. The guide rails 441 are inclined, and each guide rail 441 is parallel to the first inclined surface 445 on the corresponding clamping block 440. One chute is arranged on each limiting plate 410. The chute is inclined, and each guide rail 441 is slidably arranged in one chute.

[0039] In this embodiment, a detection device for a metal material includes the above-mentioned detection fixture, and further includes a tensile force detector 200. The tensile force detector 200 is fixedly arranged on the lifting platform 300, and the tensile force detector 200 is fixedly connected to the housing 400 located on the lifting platform 300. The tensile force detector 200 is used to detect the tensile force applied to the workpiece.

[0040] Working process: Place the lower end of the workpiece at the clamping mechanism on the lower side, and then start the third hydraulic cylinder. According to the length of the workpiece, move the lifting platform 300 to a suitable position so that the upper end of the workpiece is at the clamping mechanism on the upper side. At this time, the two clamping blocks 440 in each clamping mechanism are respectively located on both sides of the workpiece along the first direction.

[0041] Activate the second hydraulic cylinder 430. The second hydraulic cylinder 430 extends, thereby pushing the pressure plate 431 to move. The pressure plate 431 drives the clamping block 440 to move through the same-position platform 460. The clamping block 440 moves along the direction from the second side to the first side of the clamping block 440. Due to the mutual cooperation of the first inclined surface 445 and the second inclined surface, the moving directions of the clamping blocks 440 along the vertical direction approach each other. The pressing pins 444 on each clamping block 440 first contact the workpiece, and the pressing pins 444 press pits on the workpiece, thereby achieving clamping to increase the frictional force. After the pressing pins 444 press pits on the workpiece, the flexible interlayer 451 contacts the workpiece, and the flexible interlayer 451 fills the part where the pressing pins 444 do not contact the workpiece, further increasing the frictional force. The frictional forces of the two clamping methods are superimposed on each other, and more frictional force can be provided when clamping the workpiece to prevent the clamping block 440 from separating from the workpiece.

[0042] The distance between the end of the pressing pin 444 in contact with the workpiece and the side of the sandwich core 450 in contact with the workpiece is the target distance. Before the clamping mechanism clamps the workpiece, first, according to the hardness of the workpiece, activate the first hydraulic cylinder, and introduce hydraulic oil into the hydraulic cavity 442 through the hydraulic oil pipe, thereby pushing the sandwich core 450 to slide along the first direction in the installation groove to change the size of the target distance, so that the target distance is within the first preset value.

[0043] When the workpiece is relatively soft, the pits pressed by the pressing pins 444 are likely to be too deep, which is likely to cause damage to the metal phase of the metal material. At this time, the flexible interlayer 451 needs to provide a large frictional force to reduce the depth of the pits on the workpiece surface while ensuring that the frictional force provided by the clamping block 440 is sufficient. When the workpiece is relatively hard, it is not easy to press pits on the surface of the workpiece. Therefore, the flexible interlayer 451 needs to provide a large frictional force to enable the clamping block 440 to provide sufficient frictional force to prevent separation from the workpiece.

[0044] Therefore, when the workpiece is relatively soft or hard, it is necessary to make the first preset value smaller, so that the flexible interlayer 451 provides a large frictional force. When the hardness of the workpiece is moderate, the flexible interlayer 451 does not need to provide a large frictional force. In the range where the hardness of the workpiece gradually changes from relatively soft to moderate, the first preset value is positively correlated with the hardness of the workpiece, and the first preset value gradually increases. In the range where the hardness of the workpiece gradually changes from moderate to relatively hard, the first preset value is negatively correlated with the hardness of the workpiece, and the first preset value gradually decreases.

[0045] After that, while the pressing pins 444 are in contact with the workpiece, activate the third hydraulic cylinder to pull the lifting platform 300 upward. At the same time, activate the first hydraulic cylinder again to introduce hydraulic oil into the hydraulic cavity 442, thereby pushing the sandwich core 450 to continue approaching the workpiece, and further changing the size of the target distance on the premise that the target distance is within the first preset value, so that the target distance is within the second preset value.

[0046] The second preset value is adjusted according to the tensile capacity of the workpiece. When the tensile capacity of the workpiece is strong, it is not necessary for the flexible sandwich layer 451 to provide a large frictional force. Therefore, the sandwich core 450 moves less toward the workpiece, and the difference between the first preset value and the second preset value is small. When the tensile capacity of the workpiece is weak, it is necessary for the flexible sandwich layer 451 to provide a large frictional force to prevent tearing between the pressing needle 444 and the workpiece. Therefore, the sandwich core 450 moves more toward the workpiece, and the difference between the first preset value and the second preset value is large.

[0047] When the lifting platform 300 moves upward, the clamping mechanism on the lifting platform 300 stretches the workpiece, and the tensile force detector 200 detects the workpiece. When the detection is completed, the clamping mechanism resets and takes out the workpiece.

[0048] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A detection fixture, characterized in that: It includes a bracket and two clamping mechanisms; the clamping mechanisms are arranged on the bracket, the two clamping mechanisms are sequentially distributed along the up and down directions, and the two clamping mechanisms can move relative to each other along the vertical direction; Each clamping mechanism comprises a housing and two clamping assemblies; the two clamping assemblies are sequentially distributed along a horizontal direction, the direction in which the two clamping assemblies are sequentially distributed is a first direction, and the two clamping assemblies are close to each other for clamping a workpiece; each clamping assembly comprises a clamping block, a sandwich core, a flexible interlayer and a driving unit; the clamping block is slidably arranged in the housing, and a mounting groove is provided on one side of the clamping block close to an adjacent clamping block along the first direction, and a plurality of pressing pins are fixedly arranged in the mounting groove, the pressing pins are horizontally arranged, and the pressing pins are used to abut against the workpiece; The core is horizontally slidably arranged in the installation groove, and the driving unit is used to drive the core to slide horizontally; a plurality of first pinholes are opened on the core, and the flexible interlayer is fixedly arranged on the side of the core close to the workpiece, and a plurality of second pinholes are opened on the flexible interlayer, and each pressure needle passes through a first pinhole and a second pinhole in sequence; the flexible interlayer is used to abut against the workpiece.

2. A detection fixture according to claim 1, characterized in that: Each clamping block is provided with hydraulic cavities on both sides along the second direction, the second direction is horizontal, and the second direction is perpendicular to the first direction, and the two hydraulic cavities are connected with the mounting groove; each sandwich core is fixedly provided with hydraulic wing plates on both sides along the second direction, the hydraulic wing plates are vertically arranged, and each hydraulic wing plate is slidably arranged in a hydraulic cavity; hydraulic oil is arranged in the hydraulic cavity; each clamping block is provided with two hydraulic ports, and each hydraulic port is connected with the hydraulic cavity; the driving unit includes a first hydraulic cylinder, the first hydraulic cylinder is fixedly arranged on the bracket, and the first hydraulic cylinder is provided with two hydraulic oil pipes, and each hydraulic oil pipe is connected with a hydraulic port.

3. A detection fixture according to claim 2, characterized in that: The two sides of the clamping block along the up and down directions are respectively the first side and the second side, and the side of the clamping block close to the clamping block in the adjacent clamping mechanism is the first side; the mounting groove is divided into a first part, a second part and a third part in sequence along the direction from the second side to the first side of the clamping block, wherein the multiple pressing pins in the third part of the mounting groove have a length that gradually decreases along the direction from the second side to the first side.

4. A detection fixture according to claim 3, characterized in that: Along the first direction, a first inclined surface is provided on the side of the clamping block away from the workpiece, and along the direction from the second side to the first side of the clamping block, the first inclined surface gradually approaches the workpiece; two second inclined surfaces are provided on the outer shell, and the two second inclined surfaces are distributed in sequence along the horizontal direction, each second inclined surface is offset against a first inclined surface, and each second inclined surface is arranged parallel to the first inclined surface it is offset against.

5. The detection fixture according to claim 1, characterized in that: The bracket includes a base and a gantry, the gantry is fixedly arranged on the base, and a lifting platform capable of sliding up and down is arranged on the gantry; the shell of the clamping mechanism on the upper side is arranged on the lifting platform; the shell of the clamping mechanism on the lower side is fixedly arranged on the base.

6. A detection fixture according to claim 3, characterized in that: Each clamping mechanism also includes a driving assembly, which includes a second hydraulic cylinder and a pressure plate; the second hydraulic cylinder is vertically arranged, and the upper end of the second hydraulic cylinder is fixedly connected to the outer shell; the pressure plate is fixedly arranged at the lower end of the second hydraulic cylinder; a positioning platform is fixedly arranged on the second side of the clamping block, and a semicircular groove is opened in the positioning platform; each pressure plate is arranged in two semicircular grooves in a clamping mechanism.

7. The detection fixture according to claim 5, characterized in that: A third hydraulic cylinder is fixedly arranged on the gantry, and an extended end of the third hydraulic cylinder is vertically arranged and fixedly connected to the lifting platform.

8. The detection fixture according to claim 4, characterized in that: Two limit assemblies are arranged on each shell, and the two limit assemblies are distributed in sequence along the first direction. Each limit assembly includes two limit plates, and the two limit plates are distributed in sequence along the second direction. The limit plates are detachable, and each clamping block is located between the two limit plates in a limit assembly.

9. A detection fixture according to claim 8, characterized in that: Each clamping block is provided with guide rails on both sides along the second direction, the guide rails are inclined, and each guide rail is parallel to the first inclined surface on the clamping block; each limiting plate is provided with a slide groove, the slide groove is inclined, and each guide rail is slidably arranged in a slide groove.

10. A metal material testing device, comprising a testing fixture as claimed in any one of claims 1 to 9, characterized in that: It also includes a tension detector, which is fixedly arranged on the lifting platform and fixedly connected to a shell on the lifting platform. The tension detector is used to detect the tension applied to the workpiece.

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