CN211652352U

CN211652352U - Miniature uniaxial stretching device based on automatic sample changing

Info

Publication number: CN211652352U
Application number: CN202020111278.7U
Authority: CN
Inventors: 黄兴民; 黄沥; 陈学双; 梁红琴
Original assignee: Southwest Jiaotong University
Current assignee: Jiangsu Huju Cultural Industry Development Co ltd; Nanjing Sundeli Material Technology Co ltd
Priority date: 2020-01-17
Filing date: 2020-01-17
Publication date: 2020-10-09
Anticipated expiration: 2030-01-17

Abstract

The utility model discloses a miniature unipolar stretching device based on automatic change appearance belongs to the material test field, including mounting base and the experimental group of setting on mounting base, set up at mounting base and with experimental group's connection first actuating mechanism and set up on the chuck and be located the sample presentation group of experimental group below. The utility model realizes the uniaxial tension test which is uninterrupted, can be repeated for many times and has higher automation degree, greatly improves the test efficiency and lightens the workload of the tester; furthermore the utility model discloses help the record and the extraction of test data such as load, displacement to can cooperate laser confocal microscope (LSCM) system or Scanning Electron Microscope (SEM) system or Electron Back Scattering Diffraction (EBSD) system to survey and analyze the micro-structure dynamic evolution of test material, realize that miniature sample uniaxial tension process normal position observation test device function extends.

Description

Miniature uniaxial stretching device based on automatic sample changing

Technical Field

The utility model relates to a material test field, concretely relates to miniature unipolar stretching device based on automatic trade appearance.

Background

In recent years, with the rapid development of microscopic imaging technology and instruments, people have more in-depth knowledge on the mutual association between the microstructure and the macroscopic service performance of materials, thereby promoting the rapid development of the material field. At present, the traditional mechanical property testing equipment is automated, but the size of a used standard sample is large, and dynamic and real-time monitoring of microscopic or even microscopic scales (hundreds of micrometers or even hundreds of nanometers) cannot be carried out under a microscopic imaging instrument, namely in-situ microscopic observation. Therefore, material engineers and researchers try to complete material testing by using micro samples, and a micro in-situ mechanical testing device which can be matched with a laser confocal microscope, a scanning electron microscope and other equipment to perform microstructure characterization and observation is urgently expected to be obtained.

At present, compared with the traditional large-scale mechanical equipment, the micro in-situ mechanical testing device developed at present is smaller and more precise in structure, but the difficulty and the workload of the test operation are larger. For example, manual installation and replacement is cumbersome due to the small size of the specimen itself. Especially to the in-situ observation test that needs to carry out in vacuum state or closed test condition such as scanning electron microscope, need constantly open the chamber door and carry out manual change sample, it is consuming time more hard, the repeatability is poor and leads to manual error more.

Therefore, how to provide a miniature in-situ mechanical test device which has a compact structure, is suitable for small samples, can be matched with a microstructure characterization device to perform in-situ microscopic observation, and can realize automatic sample change is a technical problem which needs to be solved by the technical personnel in the field.

SUMMERY OF THE UTILITY MODEL

The utility model discloses to the micro observation experiment of current normal position mechanics change with the installation sample consuming time hard, precision and efficiency are lower not enough, provide a miniature unipolar stretching device based on automatic trade appearance, concrete technical scheme as follows:

a miniature uniaxial tension device based on automatic sample changing comprises a mounting base, a test group arranged in the mounting base, a first driving mechanism arranged on the mounting base and used for driving the test group, and a sample conveying group arranged at the lower end of the mounting base and used for conveying a sample to be tested into the test group;

the test groups included: the device comprises a first cross beam, a second cross beam, a chuck, a second driving mechanism, a displacement sensor and a load sensor; the first cross beam and the second cross beam are arranged on the mounting base and are parallel to each other, the chucks are respectively arranged in the first cross beam and the second cross beam, and the second driving mechanism is respectively arranged in the first cross beam and the second cross beam and is used for driving the chucks to rotate; the load sensor is arranged between the mounting base and the first cross beam, and the displacement sensor is arranged between the first cross beam and the second cross beam;

the sample sending group comprises: the sample feeding frame, the third driving mechanism, the sample bin and the ejector rod are arranged in the sample feeding frame; the third driving mechanism is arranged on the sample feeding frame, the sample bin is arranged on the sample feeding frame and is positioned at the bottom side of the test group, the ejector rod is arranged at the output end of the third driving mechanism, and an ejector rod hole matched with the ejector rod is formed in the bottom side of the sample bin.

Preferably, the second driving mechanism comprises a second driving motor arranged on the mounting base and a threaded rod arranged at the output end of the second driving motor, a first push cylinder in threaded connection with the threaded rod is sleeved at the middle end of the threaded rod, a second push cylinder in threaded connection with the threaded rod is arranged at the front end of the threaded rod, a fixed pressing plate is arranged at the front end of the second push cylinder, and key grooves are formed in the outer sides of the first push cylinder and the second push cylinder; the chuck is provided with a mounting groove matched with the first push cylinder and the second push cylinder, and splines corresponding to the key grooves are arranged in the mounting groove.

Preferably, the chucks are all provided with sample fixing grooves, and the sample fixing grooves are arranged at the end parts of the chucks far away from the mounting grooves.

Preferably, the third driving mechanism comprises a third driving motor arranged on the sample feeding frame, a third transmission group arranged at the output end of the third driving motor, and a transmission cam arranged at the output end of the third transmission group and matched with the ejector rod.

Preferably, the third transmission set comprises a third transmission shaft arranged on the sample feeding frame and rotatably connected with the sample feeding frame, a helical gear arranged at the output end of the third driving motor and in threaded connection with the third transmission shaft, and a transmission cam arranged on the third transmission shaft.

Preferably, the sample feeding frame is arranged below the sample bin, the output end of the auxiliary motor is provided with an auxiliary cam, the sample feeding frame is arranged below the sample bin and is provided with an auxiliary ejector rod matched with the auxiliary cam, and the sample bin is internally provided with an auxiliary backing plate.

Preferably, the first driving mechanism comprises a first driving motor, a transmission part arranged at the output end of the first driving motor, and a lead screw arranged at the output end of the transmission part, the lead screw respectively passes through the first cross beam and the second cross beam and is in threaded connection with the first cross beam and the second cross beam, and the thread directions of two sides of the lead screw are opposite.

Preferably, the threaded sleeve is sleeved between the screw rod and the first cross beam, the screw rod is in threaded connection with the threaded sleeve, the threaded sleeve is in sliding connection with the first cross beam, and the first cross beam is detachably provided with a fixing pin for positioning the threaded sleeve.

Preferably, the transmission part comprises a transmission shaft arranged on the mounting base, a first transmission bevel gear arranged on the transmission shaft and in threaded connection with the output end of the first driving motor, and a second transmission bevel gear respectively arranged on the first cross beam and the second cross beam and in threaded connection with the transmission shaft.

The utility model discloses following beneficial effect has:

the utility model discloses a to await measuring the sample and place respectively on the chuck and fixed, then start first driving motor and transmit first driving motor's rotatory moment of torsion through transmission portion to the lead screw, the rotatory in-process drive of lead screw rather than threaded connection and revolve to opposite first crossbeam and second crossbeam and chuck and keep away from the motion each other, realize the tensile to the sample that awaits measuring from this. The utility model discloses help the record and the extraction of test data such as load, displacement to can cooperate laser confocal microscope or SEM system or EBSD system to survey and analyze the microscopic structure dynamic evolution of test material, the realization of the microscopic observation test device development function of normal position promptly.

Simultaneously the utility model discloses in set up the third actuating mechanism drive ejector pin on sending the appearance frame with the sample storehouse in the sample to be measured inside the chuck is pushed up, second driving motor drives the threaded rod rotatory, and through the threaded connection cooperation of first pusher, second pusher and threaded rod and first pusher, keyway on the second pusher and the spline fit in the mounting groove, make first pusher and second pusher syntropy rectilinear movement, and will release the mounting groove top with the solid fixed pressing plate that the second pusher is connected, the chuck top promptly. When the first pushing barrel is screwed with the threaded rod, the second driving motor drives the threaded rod to rotate and enables the chuck to drive the sample to be tested to rotate through the matching of the key groove and the spline. In a similar way, the second driving motor rotates reversely, the fixed pressing plate is retracted, and when the second pushing cylinder is screwed with the threaded rod, the second driving motor drives the threaded rod to rotate and enables the chuck to drive the sample to be tested to rotate reversely through the matching of the key groove and the spline. Therefore, the sample to be tested required by the next tensile test is placed in the chuck, the tensile test and in-situ observation which are uninterrupted, can be repeated for many times and have higher automation degree are realized, the test efficiency is greatly improved, and the workload of testers is reduced.

Drawings

Fig. 1 is a schematic structural view of the present invention;

fig. 2 is a schematic structural diagram of a second driving mechanism in the present invention;

fig. 3 is an exploded view of a second driving mechanism of the present invention;

fig. 4 is a cross-sectional view of a second drive mechanism of the present invention;

FIG. 5 is a schematic structural view of a sample feeding set in the present invention;

fig. 6 is a schematic structural diagram of the middle sample chamber of the present invention.

In the figure: 1-mounting a base; 2-test group; 3-a first drive mechanism; 4-sample sending group; 21-a first beam; 22-a second beam; 23-a chuck; 24-a second drive mechanism; 25-a displacement sensor; 26-a load cell; 42-sample feeding rack; 43-a third drive mechanism; 44-a sample compartment; 45-ejector pin; 46-a jack rod hole; 242-a second drive motor; 243-threaded rod; 245-a first pusher; 246-second pusher; 247-fixing a pressure plate; 248-a keyway; 241-mounting grooves; 249-spline; 6, sample fixing groove; 431-a third drive motor; 432-a third drive group; 433-a drive cam; 4321-third drive shaft; 4322-bevel gear; 5-an auxiliary motor; 51-an auxiliary cam; 52-auxiliary mandril; 441-an auxiliary backing plate; 31-a first drive motor; 32-a transmission part; 33-a lead screw; 8-thread bush; 9-a fixed pin; 321-a transmission shaft; 322-first drive bevel gear; 323-second drive bevel gear.

Detailed Description

The principles and features of the present invention are described below in conjunction with the following drawings, the examples given are only intended to illustrate the present invention and are not intended to limit the scope of the present invention.

Examples

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the accompanying drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present invention, it should be noted that the terms "first", "second", and the like are used only for distinguishing the description, and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should also be noted that, unless explicitly stated or limited otherwise, the terms "disposed," "connected," and "connected" are to be construed broadly, and may for example be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Some embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The embodiments described below and the features of the embodiments can be combined with each other without conflict.

Referring to fig. 1 and 5, the utility model discloses a mounting base 1, set up on mounting base 1 and be used for carrying on the experimental group 2 of normal position, set up on mounting base 1 and with experimental group 2 the first actuating mechanism 3 of being connected and set up on the test bench and be located experimental group 2 below send a kind group 4. The first driving mechanism 3 is used for providing tensile force required by the test group 2 in the in-situ observation test process, and the sample sending group 4 is used for placing a sample to be tested in the test group 2, so that long-time waiting of a tester is avoided.

With further reference to fig. 1 to 2, the test group 2 includes a first beam 21 disposed on the mounting base 1, a second beam 22 disposed on the mounting base 1 and parallel to the first beam 21, a collet 23 disposed in the first beam 21 and the second beam 22, second driving mechanisms 24 respectively disposed in the collet 23, and a displacement sensor 25 disposed between the first beam 21 and the second beam 22. Be equipped with the sample fixed slot 6 that is used for fixed sample that awaits measuring on chuck 23, the utility model discloses a sample fixed slot 6 that sets up on chuck 23 is fixed the sample that awaits measuring, has improved the utility model discloses to the location efficiency of the sample that awaits measuring. Be equipped with load sensor 26 between mounting base 1 and the first crossbeam 21, the utility model discloses in the load sensor 26 that sets up between mounting base 1 and second crossbeam 22 will await measuring the sample in the normal position stress condition transmission to the computer among the observation test, the testing personnel of being convenient for carry out the analysis.

With further reference to fig. 1, the first driving mechanism 3 includes a first driving motor 31, a transmission part 32 disposed at an output end of the first driving motor 31, and two lead screws 33 disposed at an output end of the transmission part 32. The screw 33 passes through the first beam 21 and is connected with the second beam 22 in a threaded manner, and the thread directions of both sides of the screw 33 are opposite. Meanwhile, the first beam 21 is also connected with the screw 33 by screw threads. The transmission part 32 includes a transmission shaft 321 provided on the mounting base 1, a first transmission bevel gear 322 provided on the transmission shaft 321 and threadedly connected to the output end of the first driving motor 31, and a second transmission bevel gear 323 provided on the first and

second beams

21 and 22, respectively, and threadedly connected to the transmission shaft 321.

During the experiment, the tester places the sample that awaits measuring on chuck 23 and fixes, then starts first driving motor 31 and transmits first driving motor's 31 rotation torque to lead screw 33 through transmission portion 32, and the rotatory in-process drive of lead screw 33 keeps away from each other with its threaded connection's first crossbeam 21 and second crossbeam 22 and chuck 23, realizes the tensile function to the sample that awaits measuring from this, the utility model discloses still can regard as equipment accessories such as laser confocal microscope (LSCM) system or SEM system or EBSD system, observe the change of the area of concern (equivalence section) interior microscopic structure among the sample tensile process to obtain miniature sample load displacement curve through displacement sensor and load sensor.

Referring further to fig. 3 to 6, the sample feeding set 4 includes a sample feeding rack 42 disposed on the mounting base 1, a third driving mechanism 43 disposed on the sample feeding rack 42, a sample chamber 44 disposed on the sample feeding rack 42 and located at the bottom side of the test set 2, and a push rod 45 disposed at the output end of the third driving mechanism 43, wherein the sample chamber 44 is slidably connected to the sample feeding rack 42. The sample chamber 44 is provided at the bottom side thereof with a pin hole 46 corresponding to the pin 45. The second driving mechanism 24 includes an installation groove 241 arranged in the chuck 23, a second driving motor 242 arranged on the installation base 1, and a threaded rod 243 arranged at an output end of the second driving motor 242, a first push cylinder 245 in threaded connection with the threaded rod 243 is sleeved outside the middle end of the threaded rod 243, a second push cylinder 246 in threaded connection with the threaded rod 243 is arranged at the front end of the threaded rod 243, a fixed pressing plate 247 penetrating through the installation groove 241 and slidably connected with the installation groove 241 is arranged at the front end of the second push cylinder 246, key grooves 248 are arranged outside the first push cylinder 245 and the second push cylinder 246, and splines 249 corresponding to the key grooves 248 are arranged in the installation groove 241. Be equipped with supplementary backing plate 441 in sample storehouse 44, the utility model discloses a sample is released to supplementary backing plate 441 that sets up in sample storehouse 44 to reach the purpose of steadily releasing and protection sample that awaits measuring.

The utility model discloses in send appearance frame 42 to go up and be located sample storehouse 44 below and be equipped with auxiliary motor 5, auxiliary motor 5 output is equipped with supplementary cam 51, send appearance frame 42 to go up and be located sample storehouse 44 below be equipped with supplementary cam 51 complex supplementary ejector pin 52, supplementary motor 5 drive supplementary cam 51 is rotatory, makes supplementary cam 51 jack-up supplementary ejector pin 52 and with sample storehouse 44 jack-up, shortens the distance between sample storehouse 44 and chuck 23. The sample chamber 44 is jacked up by the auxiliary jacking rod 52 and butted with the chuck 23, and then the sample to be tested in the sample chamber 44 is jacked into the chuck 23 by the jacking rod 45. After the ejector rod 45 pushes the sample to be tested in the sample chamber 44 to the chuck 23, the second driving motor 242 drives the threaded rod 243, and the first pushing cylinder 245 and the second pushing cylinder 246 linearly move in the same direction through the threaded connection and matching of the first pushing cylinder 245, the second pushing cylinder 246 and the threaded rod 243 and the matching of the key slots 248 and the splines 249 arranged on the first pushing cylinder 245 and the second pushing cylinder 246, and push the fixed pressing plate 247 connected with the second pushing cylinder 246 out of the mounting groove 241, namely above the chuck 23. When the first pushing cylinder 245 is screwed with the threaded rod 243, the second driving motor 242 rotates through the cooperation of the key slot 248 and the spline 249, and the chuck 23 drives the sample to be tested to rotate. Similarly, the second driving motor 242 rotates in the reverse direction, the fixed pressing plate 247 retracts, and when the second pushing cylinder 246 is screwed with the threaded rod 243, the second driving motor 242 drives the threaded rod 243 to rotate and the chuck 23 drives the sample to be tested to rotate in the reverse direction through the matching of the key slot 248 and the spline 249.

With further reference to fig. 4 to 5, the third driving mechanism 43 includes a third driving motor 431 disposed on the sample-feeding rack 42, a third transmission group 432 disposed at an output end of the third driving motor 431, and a transmission cam 433 disposed at an output end of the third transmission group 432 and engaged with the push rod 45. The third transmission set 432 comprises a third transmission shaft 4321 arranged on the sample feeding rack 42 and rotatably connected with the sample feeding rack 42, a helical gear 4322 arranged at the output end of the third driving motor 431 and in threaded connection with the third transmission shaft 4321, and a transmission cam 433 arranged on the third transmission shaft 4321. After the chuck 23 rotates and faces the sample chamber 44, the third driving motor 431 is started and drives the driving cam 433 to rotate through the motion transmission of the third transmission set 432, and the ejector rod 45 is lifted after the driving cam 433 contacts with the ejector rod 45, so that the function that the ejector rod 45 ejects the sample to be tested in the sample chamber 44 into the chuck 23 is realized.

The following is the utility model discloses the automatic process of changing a design of miniature unipolar stretching device based on automatic change a design explains.

Referring to fig. 2 and 3, after the test set 2 completes the tensile test, the second driving motor 242 is started to rotate, and the second driving motor 242 drives the threaded rod 243 to rotate, so that the first pushing cylinder 245 matched with the threaded rod 243 drives the chuck 23 to turn downwards through the key slot matching until the sample fixing slot 6 of the chuck 23 faces the sample sending set 4. The second driving motor 242 is activated to rotate in reverse, and the threaded rod 243 rotates in reverse, so that the first pusher 245 and the second pusher 246 engaged therewith move in a direction to approach the second driving motor 242, thereby retracting the stationary platen 247 defining the sample. The sample automatically falls off from the sample fixing groove 6 under the action of gravity. Then, the sample feeding unit 4 is started to align the sample chamber 44 containing the sample with the sample fixing groove 6, and the third driving unit 432 is driven by the third driving motor 431 to drive the push rod 45 to push the sample in the sample chamber 44 into the sample fixing groove 6. At this time, the fixed pressing plate 247 is extended from the chuck 23 by the second driving mechanism 24 according to the above-mentioned procedure and inserted between the top layer sample and the second sample, thereby fixing the sample. The sample feeding group 4 moves downwards to withdraw, the sample bin 44 is separated from the chuck 23, then the chuck 23 is overturned to the sample fixing groove 6 to be upward under the action of the second driving mechanism, the automatic sample changing operation is completed, and the sample tensile test is carried out again.

In order to facilitate the insertion of the fixed pressing plate 247 between the top layer sample and the second sample during the sample changing process, ring-shaped gaskets may be sleeved on both sides of the samples during the sample preparation process, so as to form an insertion gap between two adjacent samples in the sample chamber 44, or both ends of the samples may be machined into wedge-shaped surfaces.

The utility model discloses a both ends of the sample that will await measuring are placed respectively on chuck 23 and are fixed, then start first driving motor 31 and transmit first driving motor 31's torsional moment to lead screw 33 through transmission portion 32, lead screw 33 is rotatory in-process drive rather than threaded connection and revolve to opposite first crossbeam 21 and second crossbeam 22 and chuck 23 keep away from each other, realize from this the normal position unipolar stretching of the sample that awaits measuring, and observe each item data and the microcosmic change in the sample that awaits measuring stretching process through laser confocal microscope (LSCM) system or SEM/EBSD system and displacement sensor 25, then place the sample that awaits measuring that next normal position observation test needs in chuck 23 through sending appearance group 4, realized incessantly, can be repeated many times, tensile test and normal position observation that degree of automation is higher, test efficiency has been improved by a wide margin, the workload of the testing personnel is reduced.

Meanwhile, in the test process, the tester adjusts the angle of the chuck 23 by using the second driving motor 242, so that the tester can observe the surface texture of the sample by using the SEM system, and can also convert the angle to obtain fine texture information such as texture, grain size and the like by using the EBSD system. The threaded sleeve 8 is sleeved outside the screw rod 33 and between the screw rod and the second cross beam 22, the second cross beam 22 is provided with a fixing pin 9, and the fixing pin 9 penetrates through the second cross beam 22 and is detachably connected with the threaded sleeve 8. When the tester needs to dismantle the device or debug manually, the tester can take out the fixed pin 9 on the second crossbeam 22, but make be in slidable state and reverse rotation thread bush 8 between second crossbeam 22 and the thread bush 8, make thread bush 8 resume initial position, then slide second crossbeam 22 and make second crossbeam 22 also resume initial position, insert fixed pin 9 and make and be connected fixedly between second crossbeam 22 and the thread bush 8, long-time the waiting that resets has been avoided from this.

It is to be noted that, in this document, the terms "comprises", "comprising" or any other variation thereof are intended to cover a non-exclusive inclusion, so that an article or apparatus including a series of elements includes not only those elements but also other elements not explicitly listed or inherent to such article or apparatus. Without further limitation, an element defined by the phrase "comprising … …" does not exclude the presence of additional like elements in the article or device comprising the element.

The above description is only for the preferred embodiment of the present invention, and should not be construed as limiting the present invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.

Claims

1. The utility model provides a miniature uniaxial tension device based on automatic change appearance which characterized in that includes: the device comprises a mounting base (1), a test group (2) arranged in the mounting base (1), a first driving mechanism (3) arranged on the mounting base (1) and used for driving the test group (2), and a sample conveying group (4) arranged at the lower end of the mounting base (1) and used for conveying a sample to be tested into the test group (2);

the test group (2) comprises: a first beam (21), a second beam (22), a chuck (23), a second driving mechanism (24), a displacement sensor (25) and a load sensor (26); the first cross beam (21) and the second cross beam (22) are arranged on the mounting base (1) and are parallel to each other, the chucks (23) are respectively arranged in the first cross beam (21) and the second cross beam (22), and the second driving mechanism (24) is respectively arranged in the first cross beam (21) and the second cross beam (22) and is used for driving the chucks (23) to rotate; the load sensor (26) is arranged between the mounting base (1) and the first cross beam (21), and the displacement sensor (25) is arranged between the first cross beam (21) and the second cross beam (22);

the sample presentation group (4) comprises: a sample feeding frame (42), a third driving mechanism (43), a sample bin (44) and a mandril (45); the third driving mechanism (43) is arranged on the sample feeding frame (42), the sample bin (44) is arranged on the sample feeding frame (42) and located at the bottom side of the test group (2), the ejector rod (45) is arranged at the output end of the third driving mechanism (43), and an ejector rod hole (46) matched with the ejector rod (45) is formed in the bottom side of the sample bin (44).

2. The miniature uniaxial stretching device based on automatic sample changing according to claim 1, wherein the second driving mechanism (24) comprises a second driving motor (242) arranged on the mounting base (1) and a threaded rod (243) arranged at the output end of the second driving motor (242), a first push cylinder (245) in threaded connection with the threaded rod (243) is sleeved at the middle end of the threaded rod (243), a second push cylinder (246) in threaded connection with the threaded rod (243) is arranged at the front end of the threaded rod (243), a fixed pressing plate (247) is arranged at the front end of the second push cylinder (246), and key grooves (248) are arranged on the outer sides of the first push cylinder (245) and the second push cylinder (246);

the clamping head (23) is provided with a mounting groove (241) matched with the first push cylinder (245) and the second push cylinder (246), and a spline (249) corresponding to the key groove (248) is arranged in the mounting groove (241).

3. The miniature uniaxial stretching device based on automatic sample changing according to claim 2, wherein each of the chucks (23) is provided with a sample fixing groove (6), and the sample fixing grooves (6) are arranged at the end parts of the chucks (23) far away from the mounting groove (241).

4. The automatic sample changing-based micro uniaxial stretching device according to claim 2, wherein the third driving mechanism (43) comprises a third driving motor (431) arranged on the sample sending rack (42), a third transmission group (432) arranged at the output end of the third driving motor (431), and a transmission cam (433) arranged at the output end of the third transmission group (432) and matched with the mandril (45).

5. The automatic sample changing-based micro uniaxial stretching device according to claim 4, wherein the third transmission set (432) comprises a third transmission shaft (4321) arranged on the sample feeding frame (42) and rotatably connected with the sample feeding frame (42), a helical gear (4322) arranged at the output end of the third driving motor (431) and in threaded connection with the third transmission shaft (4321), and the transmission cam (433) is arranged on the third transmission shaft (4321).

6. The automatic sample changing-based miniature single-shaft stretching device according to claim 5, wherein an auxiliary motor (5) is arranged on the sample feeding frame (42) and below the sample bin (44), an auxiliary cam (51) is arranged at the output end of the auxiliary motor (5), an auxiliary mandril (52) matched with the auxiliary cam (51) is arranged on the sample feeding frame (42) and below the sample bin (44), and an auxiliary backing plate (441) is arranged in the sample bin (44).

7. The automatic sample changing-based micro uniaxial stretching device according to any one of claims 1 to 6, wherein the first driving mechanism (3) comprises a first driving motor (31), a transmission part (32) arranged at the output end of the first driving motor (31), and a lead screw (33) arranged at the output end of the transmission part (32), the lead screw (33) respectively passes through the first beam (21) and the second beam (22) and is in threaded connection with the first beam (21) and the second beam (22), and the thread directions of two sides of the lead screw (33) are opposite.

8. The automatic sample changing-based micro uniaxial stretching device according to claim 7, wherein a threaded sleeve (8) is sleeved between the lead screw (33) and the first beam (21), the lead screw (33) is in threaded connection with the threaded sleeve (8), the threaded sleeve (8) is in sliding connection with the first beam (21), and a fixing pin (9) for positioning the threaded sleeve (8) is detachably arranged on the first beam (21).

9. The micro uniaxial stretching device based on the automated sample changing according to claim 7, wherein the transmission part (32) comprises a transmission shaft (321) arranged on the mounting base (1), a first transmission helical gear (322) arranged on the transmission shaft (321) and in threaded connection with the output end of the first driving motor (31), and a second transmission helical gear (323) arranged on the first beam (21) and the second beam (22) respectively and in threaded connection with the transmission shaft (321).