Axial force uniform distribution concentric fixture tensile testing machine

Abstract

The present invention belongs to the field of tensile test application equipment, and in particular, relates to a axial force uniformly distributed concentric clamp tensile testing machine. It includes a frame and a lower horizontal push hydraulic clamp arranged on the top of the frame, an upper horizontal push hydraulic clamp is arranged above the lower horizontal push hydraulic clamp, a loading hydraulic cylinder is also arranged on the frame, the upper horizontal push hydraulic clamp is arranged above the lower horizontal push hydraulic clamp through the loading hydraulic cylinder, four loading hydraulic cylinders are arranged on the frame, and the loading hydraulic cylinders are distributed in a matrix around the lower horizontal push hydraulic clamp, and a tension and compression sensor is arranged on the piston rod of the loading hydraulic cylinder. The present invention exposes the side space of the horizontal push clamp through the reasonable layout of the loading hydraulic cylinder, thereby facilitating maintenance and installation. At the same time, through the setting of the pull rod, the space above the frame can be used for tensile testing, and the space below the frame can be used for compression testing, thereby reducing the height of the whole machine.

Description

Technical Field

[0001] The invention belongs to the field of tensile test application equipment, and in particular relates to an axial force uniformly distributed concentric clamp tensile testing machine. Background Art

[0002] Tensile testing machine, also called material tensile testing machine and universal tensile strength testing machine, is a new generation of mechanical testing equipment that integrates computer control, automatic measurement, data acquisition, screen display, and test result processing. Tensile testing machine is mainly suitable for testing metal and non-metallic materials. In the existing tensile testing machine, the sample is clamped mainly by the upper and lower clamps, and the purpose of tensile testing is achieved by moving the clamps.

[0003] The two loading hydraulic cylinders of the existing electro-hydraulic servo tensile pressure test are respectively arranged on both sides of the main machine. When the tensile auxiliary bureau adopts a hydraulic push fixture, and the upper and lower clamp bodies adopt a cast integrated structure, the hydraulic push fixtures are respectively installed inside the upper and lower clamp bodies, and the left and right sides of the hydraulic push fixture are opposite to the piston rod of the axial loading hydraulic cylinder of the specimen. When repairing the push hydraulic cylinder of the hydraulic push fixture, the axial loading hydraulic cylinder needs to be removed before the push hydraulic cylinder can be moved out along the axis, which brings difficulties to the repair of the push hydraulic cylinder.

[0004] In addition, according to the requirements of "GB / T228.1-2010 Metal Material Tensile Test Part 1: Room Temperature Test Method" and "JB / T8612-2015 Electro-hydraulic Servo Static and Dynamic Universal Testing Machine" for the tensile specimen clamping device: During the process of applying force, the center lines of the upper and lower chucks and specimen jaws of the tensile test clamping device are coaxial with the force axis of the testing machine at any position. Due to the symmetrical setting of the loading hydraulic cylinder, the center lines of the specimens must coincide, which makes it more troublesome to install the specimens.

[0005] At the same time, the hydraulic push fixture commonly used on the tensile testing machine adopts a double hydraulic cylinder structure. The hydraulic cylinder extension rod moves relative to each other, and the specimen is clamped in a clamping manner. Whether the displacement of the two hydraulic cylinders is synchronized is the key issue. There are two main synchronization methods, one is to use a mechanical synchronization mechanism, and the other is to use a servo valve for synchronous control. When using a mechanical synchronization mechanism, a synchronous gear is often used to mesh with the left and right racks for transmission, which has the problem of difficult assembly and debugging. During long-term use, the meshing surface of the gear rack wears and the gap increases, resulting in the problem of asynchronous displacement of the two hydraulic cylinders. The displacement movement of the hydraulic cylinder is asynchronous. When the clamps at both ends of the specimen apply tension to the specimen, there is a large coaxiality error between the force center line and the specimen axis. The use of a servo valve to control the synchronous movement of the hydraulic cylinder displacement has high synchronization accuracy, but the cost of use and maintenance are high. Summary of the invention

[0006] In view of the technical problems existing in the above-mentioned tensile testing machine, the present invention proposes an axial force uniformly distributed concentric clamp tensile testing machine with reasonable design, simple structure, low cost and convenient maintenance.

[0007] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is as follows: the present invention provides an axial force uniformly distributed concentric clamp tensile testing machine, including a frame and a lower horizontal push hydraulic clamp arranged on the top of the frame, an upper horizontal push hydraulic clamp is arranged above the lower horizontal push hydraulic clamp, and a loading hydraulic cylinder is also arranged on the frame. The upper horizontal push hydraulic clamp is arranged above the lower horizontal push hydraulic clamp through the loading hydraulic cylinder. Four loading hydraulic cylinders are arranged on the frame, and the loading hydraulic cylinders are distributed in a matrix around the lower horizontal push hydraulic clamp. A tension and compression sensor is arranged on the piston rod of the loading hydraulic cylinder, and the loading hydraulic cylinder is fixedly connected to the upper horizontal push hydraulic clamp through the tension and compression sensor. The upper horizontal push hydraulic clamp and the lower horizontal push hydraulic clamp both include a clamp body and a clamping slot arranged in the middle of the clamp body, the side walls of the clamping slot are provided with fixed jaws and movable jaws arranged opposite to each other, the end of the fixed jaw away from the movable jaw is provided with a jaw fixing mechanism, the end of the movable jaw away from the fixed jaw is provided with a jaw pushing mechanism, the jaw pushing mechanism includes a horizontal push hydraulic cylinder arranged in the clamp body, the horizontal push hydraulic cylinder includes a cylinder barrel and a pushing piston sleeved on the cylinder barrel, the cylinder barrel is arranged close to the movable jaw, the pushing piston is fixedly connected to the clamp body, a moving chamber for moving the cylinder barrel is provided in the clamp body, and the cylinder barrel is connected to the movable jaw.

[0008] Preferably, a pull rod is further provided on the upper horizontal push hydraulic clamp, and the pull rod is evenly distributed around the upper horizontal push hydraulic clamp. The pull rod passes through the lower horizontal push hydraulic clamp, and a pressure plate is provided below the lower horizontal push hydraulic clamp. One end of the pull rod passes through the lower horizontal push hydraulic clamp and is evenly distributed on the pressure plate. The pull rod is detachably fixedly connected to the pressure plate.

[0009] Preferably, an extension rod is provided between the cylinder and the movable jaw, and the extension rod is eccentrically arranged between the cylinder.

[0010] Preferably, the movable cavity is arranged through one side of the clamp body, a piston flange is arranged on the clamp body, and the pushing piston is fixed on the clamp body through the piston flange.

[0011] Preferably, a guide ring for guiding is mounted on the cylinder.

[0012] Preferably, the jaw fixing mechanism includes a clamping shaft connected to the fixed jaw and a fixed screw rod arranged at one end of the clamping shaft away from the fixed jaw, a fixing nut is mounted on the fixed screw rod, and an anti-rotation pin is arranged between the fixing nut and the clamping shaft.

[0013] Preferably, a locking screw is provided between the fixed screw and the tightening shaft, and the locking screw passes through the fixed screw.

[0014] Preferably, V-shaped clamping grooves are provided on the opposing surfaces of the fixed jaw and the movable jaw.

[0015] Preferably, a protective door is also provided on the frame.

[0016] Compared with the prior art, the advantages and positive effects of the present invention are:

[0017] 1. The present invention provides an axial force uniformly distributed concentric clamp tensile testing machine. Through the reasonable layout of the loading hydraulic cylinders, the side space of the horizontal push clamp is exposed, which is convenient for maintenance and installation. At the same time, through the setting of the pull rod, the space above the frame can be used for tensile testing, and the space below the frame can be used for compression testing, thereby reducing the height of the whole machine. In addition, four loading hydraulic cylinders are fixed on the lower horizontal push hydraulic clamp to apply axial load to the upper horizontal push hydraulic clamp. The upper clamp body and the lower clamp body are four-point supports, which enhances the stability of the whole machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0019] Figure 1 A schematic diagram of the structure of the axial force uniformly distributed concentric fixture tensile testing machine provided in Example 1;

[0020] Figure 2 A schematic diagram of the structure of the axial force uniformly distributed concentric clamp tensile testing machine provided in Example 1 without the sealing door;

[0021] Figure 3 A front view of the axial force uniformly distributed concentric fixture tensile testing machine provided in Example 1;

[0022] Figure 4 A cross-sectional view of the upper horizontal push hydraulic clamp provided in Example 1;

[0023] Figure 5 It is the axial force diagram of the traditional tensile testing machine;

[0024] Figure 6 The axial force diagram of the axial force uniformly distributed concentric fixture tensile testing machine provided in Example 1;

[0025] In the above figures, 1, frame; 11, sealing door; 2, lower horizontal push hydraulic clamp; 3, upper horizontal push hydraulic clamp; 31, clamp body; 311, clamping notch; 312, piston flange; 32, fixed jaws; 33, movable jaws; 34, jaw fixing mechanism; 341, clamping shaft; 342, fixed screw rod; 343, fixing nut; 344, anti-rotation pin shaft; 345, locking screw; 35, jaw pushing mechanism; 351, cylinder barrel; 352, pushing piston; 353, extending rod; 354, guide ring; 4, loading hydraulic cylinder; 5, tension and compression sensor; 6, pull rod; 7, pressure plate. DETAILED DESCRIPTION

[0026] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0027] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments of the following disclosure.

[0028] Embodiment 1, as Figure 1 to Figure 4 As shown, the present embodiment aims to solve the technical problems existing in the tensile testing machine. To this end, the present embodiment provides an axial force uniformly distributed concentric clamp tensile testing machine, comprising a frame 1 and a lower horizontal push hydraulic clamp 2 arranged on the top of the frame 1. In the present embodiment, the frame 1 is a square frame, and a platform is arranged on the top of the frame. In the present embodiment, most of the lower horizontal push hydraulic clamp 2 is arranged extending out of the top of the frame 1, and an upper horizontal push hydraulic clamp 3 is arranged above the lower horizontal push hydraulic clamp 2. A loading hydraulic cylinder 4 is also arranged on the frame 1, and the upper horizontal push hydraulic clamp 3 is arranged above the lower horizontal push hydraulic clamp 2 through the loading hydraulic cylinder 4. A sealing door 11 is arranged on the frame 1 to shield the frame formed by the frame 1 and the dangers that may occur during the tensile test. The above structure is an existing common structure, so it is not described in detail in the present embodiment.

[0029] In order to facilitate the maintenance and installation of the lower hydraulic clamp 2 and the upper hydraulic clamp 3, in this embodiment, the two loading hydraulic cylinders 4 set on the left and right are set to four, and the loading hydraulic cylinders 4 are distributed in a matrix around the lower hydraulic clamp 2. The purpose of this setting is not only to leave space for the lower hydraulic clamp 2 and the upper hydraulic clamp 3, but also to evenly distribute the axial tension. At the same time, in order to accurately ensure the uniformity of the tension, a tension and compression sensor 5 is set on the piston rod of the loading hydraulic cylinder 4, and the loading hydraulic cylinder 4 is fixedly connected to the upper hydraulic clamp 3 through the tension and compression sensor 5. In this embodiment, the tension and compression sensor 5 is a tension and compression bidirectional column sensor, and its two ends are studs, which are respectively threadedly connected to the piston rod of the loading hydraulic cylinder 4 and the upper hydraulic clamp 3. In this embodiment, a sensor extension rod is set on the top of the bidirectional column sensor, and the sensor extension rod is fixed to the upper hydraulic clamp 3 through a leveling nut. In this way, the balance of the tension is ensured by four evenly distributed tension and compression sensors 5, thereby ensuring the accuracy of the test.

[0030] In addition, if Figure 5 , Figure 6 As shown, the traditional tensile testing machine must ensure that the center line of the sample jaws is coaxial with the test machine force axis. It is necessary to ensure that L1 and L2 are equal to ensure the accuracy of the tensile test. Therefore, it is necessary to repeatedly measure when doing the tensile test to ensure that the placement position is in the center. The axial force uniform distribution concentric clamp tensile testing machine provided in this embodiment adopts four uniformly distributed tension and compression sensors 5 and loading hydraulic cylinders 4, so that the axial force within the range of the upper and lower horizontal push hydraulic clamps 2 is the same. In this way, no matter where the sample is clamped, that is, L1 and L2 do not need to be equal, the same tension can be ensured, thereby reducing the cumbersome installation steps. In the case of eccentric installation, the accuracy of the test is also ensured. At the same time, the setting of four loading hydraulic cylinders 4 makes the lower horizontal push hydraulic clamp 2 and the upper horizontal push hydraulic clamp 3 four-point support, ensuring the stability of the whole machine. Of course, the number of loading hydraulic cylinders 4 is not necessarily set to only 4. Under the condition of ensuring the uniform distribution of axial force, corresponding adjustments can also be made. This embodiment only provides the best implementation plan.

[0031] In order to cooperate with the use of four loading hydraulic cylinders 4 and reduce the cost of use, in this embodiment, the lower horizontal push hydraulic clamp 2 and the upper horizontal push hydraulic clamp 3 both include a clamp body 31 and a clamping notch 311 arranged in the middle of the clamp body 31. In this embodiment, the clamp body 31 is arranged in a rectangular parallelepiped shape as a whole. The clamp body 31 is made of an integrated casting and has a semi-open entity structure. The purpose of such a setting is to improve the rigidity of the entire clamp. A notch is arranged in the middle of the clamp body 31 to form a clamping notch 311 for clamping test, and a clamping notch 311 is arranged on the side wall of the clamping notch 311. There are fixed jaws 32 and movable jaws 33 arranged opposite to each other. As the name implies, the fixed jaws 32 are fixed on the clamp body 31 and do not need to be moved, while the movable jaws 33 are used to move and cooperate with the fixed jaws 32 to clamp and release the sample. For this purpose, a jaw fixing mechanism 34 is provided at one end of the fixed jaw 32 away from the movable jaw 33, and a jaw pushing mechanism 35 is provided at one end of the movable jaw 33 away from the fixed jaw 32. Of course, a chamber for placing the jaw fixing mechanism 34 and the jaw pushing mechanism 35 is provided in the clamp body 31. In this embodiment, in order to facilitate movement, the fixed jaws 32 and the movable jaws 33 are both cylindrically arranged, and V-shaped clamping grooves are arranged on the opposite end faces thereof. A number of protrusions are arranged on the side walls of the V-shaped clamping grooves to increase friction and improve the clamping effect.

[0032] Taking into account the existing push hydraulic cylinder uses the extension and contraction of the pushing piston 352 to drive the movement of the movable jaw 33, this also results in the clamping force at the center point of the entire movable jaw 33 being the largest, and this also requires that the specimen must be placed at the center of the movable jaws 33 of the upper and lower clamps in order to be effectively clamped. In order to disperse the clamping force and make the clamping force of the movable jaw 33 uniform, in this embodiment, the jaw pushing mechanism 35 includes a push hydraulic cylinder arranged in the clamp body 31, the push hydraulic cylinder includes a cylinder barrel 351 and a pushing piston 352 mounted on the cylinder barrel 351. In this embodiment, the cylinder barrel 351 is arranged close to the movable jaw 33, the pushing piston 352 is fixedly connected to the clamp body 31, and a moving chamber for the movement of the cylinder barrel 351 is arranged in the clamp body 31, and the cylinder barrel 351 is connected to the movable jaw 33. In this way, when the push hydraulic cylinder is working, since the push piston 352 adopts a fixed connection method, the cylinder 351 moves. Since the area of ​​the cylinder 351 is large, the clamping force it generates covers the entire movable jaw 33, which also makes the force at various parts of the movable jaw 33 more uniform, thereby meeting the clamping of shorter specimens and improving the application range of the single push hydraulic cylinder.

[0033] Considering that both the movable jaw 33 and the cylinder 351 are columnar structures, in order to reduce the rotational freedom of the cylinder 351, in this embodiment, a protruding rod 353 is provided between the cylinder 351 and the movable jaw 33, and the protruding rod 353 and the cylinder 351 are eccentrically arranged. The rotational freedom of the cylinder 351 is limited by the eccentric arrangement. At the same time, the eccentric arrangement of the protruding rod 353 and the cylinder 351 means that the diameter of the protruding rod 353 must be smaller than the diameter of the cylinder 351, thus reducing the force area and improving the clamping force. Of course, the diameter of the protruding rod 353 is at least the same as the diameter of the movable jaw 33.

[0034] Considering that the push hydraulic cylinder is a power element, it is inevitable that it will have problems such as wear. Therefore, in order to facilitate maintenance, in this embodiment, a moving cavity is set through one side of the clamp body 31, and a piston flange 312 is set on the clamp body 31. The pushing piston 352 is fixed to the clamp body 31 through the piston flange 312, and the piston flange 312 completes the sealing of the moving cavity.

[0035] In order to further limit the rotational freedom of the cylinder 351 , a guide ring 354 is mounted on the cylinder 351 for guidance.

[0036] Taking into account that the fixed jaw 32 may need to be fine-tuned for different samples, in this embodiment, the jaw fixing mechanism 34 includes a clamping shaft 341 connected to the fixed jaw 32 and a fixed screw rod 342 arranged at the end of the clamping shaft 341 away from the fixed jaw 32. In this way, the telescopic range of the fixed jaw 32 can be adjusted by rotating the fixed screw rod 342. Similarly, in order to limit the rotational freedom of the clamping shaft 341, a fixing nut 343 is mounted on the fixing screw rod, and an anti-rotation pin shaft 344 is arranged between the fixing nut 343 and the clamping shaft 341.

[0037] In order to enable the rotation of the fixed screw 342 to drive the tightening shaft 341 to move, a locking screw 345 is provided between the fixed screw 342 and the tightening shaft 341, and the locking screw 345 is provided through the fixed screw. In this way, by rotating the fixed screw, the position of the fixed jaw 32 can be adjusted, thereby completing the accurate clamping of different samples and ensuring the coaxiality.

[0038] Through the above settings, first adjust the position of the fixed jaws 32, then place the two ends of the sample in two clamps set up above and below, control the clamping of the horizontal push hydraulic cylinder, and then carry out the relevant tensile test.

[0039] In order to further increase the function of the testing machine, in the present embodiment, a pull rod 6 is further provided on the upper horizontal push hydraulic clamp 3. The pull rod 6 is a common optical axis in existing machinery, and is also rectangular and evenly distributed on the clamp body 31 of the upper horizontal push hydraulic clamp 3. The pull rod 6 passes through the lower horizontal push hydraulic clamp 2. A pressure plate 7 is provided below the lower horizontal push hydraulic clamp 2. The pressure plate 7 is square in shape. The pull rod 6 passes through one end of the lower horizontal push hydraulic clamp 2 and is evenly distributed on the pressure plate 7. The pull rod 6 is fixedly connected to the pressure plate 7. In this way, by providing a spherical pressure plate 7 at the bottom of the lower clamp body 31 and the top of the pressure plate 7, the compression function can be realized, thereby enabling the present tensile testing machine to have the functions of tensile and compression tests.

[0040] At the same time, in order to improve the guiding accuracy and anti-tilting and overturning ability of the loading hydraulic cylinder 4 and ensure the synchronous operation of the four hydraulic cylinders, in this embodiment, multiple sealing rings and support rings are arranged in the guide sleeve of the loading hydraulic cylinder 4 to improve its guiding accuracy and anti-tilting and overturning ability.

[0041] The above description is only a preferred embodiment of the present invention and does not limit the present invention in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes and apply it to other fields. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. An axial force uniformly distributed concentric clamp tensile testing machine, comprising a frame and a lower horizontal push hydraulic clamp arranged on the top of the frame, an upper horizontal push hydraulic clamp is arranged above the lower horizontal push hydraulic clamp, and a loading hydraulic cylinder is also arranged on the frame, and the upper horizontal push hydraulic clamp is arranged above the lower horizontal push hydraulic clamp through the loading hydraulic cylinder, characterized in that: The frame is provided with four loading hydraulic cylinders, which are distributed in a matrix shape around the lower horizontal push hydraulic clamp, and a tension and compression sensor is provided on the piston rod of the loading hydraulic cylinder, and the loading hydraulic cylinder is fixedly connected to the upper horizontal push hydraulic clamp through the tension and compression sensor. The upper horizontal push hydraulic clamp and the lower horizontal push hydraulic clamp both include a clamp body and a clamping notch arranged in the middle of the clamp body, and the side walls of the clamping notch are provided with relatively arranged fixed jaws and movable jaws, and a jaw fixing mechanism is provided at one end of the fixed jaw away from the movable jaw, and a jaw pushing mechanism is provided at one end of the movable jaw away from the fixed jaw, and the jaw pushing mechanism includes a horizontal push hydraulic cylinder arranged in the clamp body, the horizontal push hydraulic cylinder includes a cylinder barrel and a pushing piston sleeved on the cylinder barrel, the cylinder barrel is arranged close to the movable jaw, the pushing piston is fixedly connected to the clamp body, a moving chamber for cylinder barrel movement is provided in the clamp body, and the cylinder barrel is connected to the movable jaw.

2. The axial force uniformly distributed concentric fixture tensile testing machine according to claim 1, characterized in that: The upper horizontal push hydraulic clamp is also provided with a pull rod, which is evenly distributed around the upper horizontal push hydraulic clamp and passes through the lower horizontal push hydraulic clamp. A pressure plate is provided below the lower horizontal push hydraulic clamp, and one end of the pull rod passes through the lower horizontal push hydraulic clamp and is evenly distributed on the pressure plate. The pull rod is detachably fixedly connected to the pressure plate.

3. The axial force uniformly distributed concentric fixture tensile testing machine according to claim 2, characterized in that: An extension rod is arranged between the cylinder barrel and the movable jaw, and the extension rod is eccentrically arranged between the cylinder barrel.

4. The axial force uniformly distributed concentric fixture tensile testing machine according to claim 3, characterized in that: The moving cavity is arranged through one side of the clamp body, a piston flange is arranged on the clamp body, and the pushing piston is fixed on the clamp body through the piston flange.

5. The axial force uniformly distributed concentric fixture tensile testing machine according to claim 4, characterized in that: A guide ring for guiding is sleeved on the cylinder barrel.

6. The axial force uniformly distributed concentric fixture tensile testing machine according to claim 5, characterized in that: The jaw fixing mechanism includes a clamping shaft connected to the fixed jaw and a fixed screw rod arranged at one end of the clamping shaft away from the fixed jaw, a fixing nut is sleeved on the fixed screw rod, and an anti-rotation pin is arranged between the fixing nut and the clamping shaft.

7. The axial force uniformly distributed concentric fixture tensile testing machine according to claim 6, characterized in that: A locking screw is arranged between the fixed screw rod and the tightening shaft, and the locking screw passes through the fixed screw rod.

8. The axial force uniformly distributed concentric fixture tensile testing machine according to claim 7, characterized in that: The opposite surfaces of the fixed jaw and the movable jaw are provided with V-shaped clamping grooves.

9. The axial force uniformly distributed concentric fixture tensile testing machine according to claim 8, characterized in that: The frame is also provided with a protective door.

Images