Low-temperature piezoelectric tensile test device capable of precisely regulating and controlling micro stress

Abstract

The invention discloses a low-temperature piezoelectric tensile test device capable of precisely regulating and controlling micro stress. The low-temperature piezoelectric tensile test device comprises a linear guide rail, the fixed end of the micro-stress adjustable clamp is fixedly mounted on one side of the linear guide rail and is used for roughly clamping one end of a thin film to be stretched; the movable end of the micro-stress adjustable clamp is in sliding connection with the linear guide rail, and the other end of the thin film to be stretched is finely clamped. The piezoelectric motor is used for driving the movable end of the micro-stress adjustable clamp to move along the linear guide rail; a resistance detector is electrically connected with the movable end of the micro-stress adjustable clamp; displacement detection is achieved through a displacement sensor. The device can realize accurate motion control under a low-temperature condition, and realizes observation of micro-scale change of film stretching.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical fixtures, in particular to a low-temperature piezoelectric tensile testing device with precise micro-stress control. Background Art

[0002] Under extremely low temperature conditions, the physical properties of film materials change significantly, and their toughness decreases significantly, becoming more fragile and brittle. This change causes the film's ability to withstand external stress to drop sharply during mechanical property testing. If the clamping force of the fixture is inappropriate, especially if it is too large, the film will be subjected to unnecessary prestress. This clamping force will not only cause premature damage to the film specimen at the beginning of the test, but will also seriously affect the accuracy of the test results. At the same time, most of these fixtures use servo motors as a power source to provide tensile force. However, under low temperature conditions, the performance of the servo motor will be affected and easily damaged, reducing the reliability, stability and accuracy of the entire test system. Existing film clamps usually use bolts to adjust the clamping range, but the adjustable range of this adjustment method is relatively small and cannot meet the needs of film materials of different sizes. When it is necessary to fix films of different sizes, it is often necessary to replace clamps of different specifications, which not only increases the complexity of the operation, but also greatly increases the cost of equipment.

[0003] In view of the above problems, an innovative solution is urgently needed. Summary of the Invention

[0004] In order to address the deficiencies in the prior art, the present application proposes a low-temperature piezoelectric tensile testing device with precise micro-stress control, which is suitable for tensile testing of thin film materials, especially for improving the reliability, stability and accuracy of the test system.

[0005] The technical solutions adopted in the present invention are as follows:

[0006] A low-temperature piezoelectric tensile testing device with precise micro-stress control, comprising:

[0007] Linear guides;

[0008] The fixed end of the micro-stress adjustable clamp is fixedly mounted on one side of the linear guide rail to roughly clamp one end of the film to be stretched;

[0009] The movable end of the micro-stress adjustable clamp is slidably connected to the linear guide rail to precisely clamp the other end of the film to be stretched;

[0010] a piezoelectric motor for driving a movable end of a micro-stress adjustable fixture to move along a linear guide rail;

[0011] a resistance detector electrically connected to the movable end of the micro-stress adjustable fixture;

[0012] Displacement sensor.

[0013] Furthermore, there are two linear guide rails, namely a first linear guide rail and a second linear guide rail, which are arranged parallel to each other.

[0014] Furthermore, the fixed end of the micro-stress adjustable fixture includes a first micrometer screw, a second micrometer screw, a first extrusion plate, a first clamping silver rod, a first circular fixture base plate, a first trapezoidal splint, and a circular fixing platform; wherein, the side wall of the first extrusion plate is fixedly connected to the side wall of the first circular fixture base plate, the first circular fixture base plate is fixed to the first trapezoidal splint, and the first trapezoidal splint is fixed to the circular fixing platform; the first micrometer screw and the second micrometer screw are arranged on the first extrusion plate; the first clamping silver rod is rotatably installed on the first extrusion plate, and the surface of the first circular fixture base plate opposite to the bottom of the first clamping silver rod is provided with a first tooth-shaped boss.

[0015] Furthermore, the movable end of the micro-stress adjustable fixture includes a third micrometer screw, a fourth micrometer screw, a second extrusion plate, a second clamping silver rod, a second circular fixture base plate, a second trapezoidal clamp plate, a trapezoidal plate, and a guide rail slide; wherein, the side wall of the second extrusion plate is fixedly connected to the side wall of the second circular fixture base plate, and the second circular clamp base plate is fixed to the second trapezoidal clamp plate; the second trapezoidal clamp plate is equipped with a trapezoidal plate, and the trapezoidal plate is kept parallel to the linear guide rail; the third micrometer screw and the fourth micrometer screw are arranged on the second extrusion plate; the second clamping silver rod is rotatably installed on the second extrusion plate, and a second toothed boss is provided on the surface of the second circular clamp base plate opposite to the bottom of the second clamping silver rod; the two sides of the second trapezoidal clamp are slidably connected to the linear guide rail through the guide rail slide.

[0016] Furthermore, the resistance detector is mounted on the guide rail slide, and the resistance detector is connected to the second clamping silver rod via a resistance tester wire.

[0017] Furthermore, the piezoelectric motor is arranged between the linear guide rails and below the trapezoidal plate.

[0018] Furthermore, a displacement sensor is installed on the third guide rail slide on the first linear guide rail.

[0019] Furthermore, the positions of the screw micrometers on the fixed end and the movable end of the microstress adjustable fixture are adjustable.

[0020] Furthermore, a spring is sleeved on the outside of the micrometer screw, and a thread is provided on the bottom end of the micrometer screw, and a thread groove is provided on the bottom plate of the clip fixture opposite to the micrometer screw.

[0021] Furthermore, the piezoelectric motor includes a piezoelectric ring, a driving beam, a V-shaped beam, a motor support frame, and a motor body. The piezoelectric ring is placed at the circular end of the driving beam with the same inner diameter as the piezoelectric ring. The bottom of the circular end of the driving beam is threaded and connected to the motor body through the thread; the triangular end of the drive is connected to the V-shaped beam, and the motor support frame is connected to the motor body through a weak spring.

[0022] Beneficial effects of the present invention:

[0023] 1. Through the design of the micro-stress adjustable fixture, the resistance change of the clamped silver rod can be used to accurately adjust the stress, which can effectively avoid the film material becoming more fragile and brittle in extreme low temperature environments, causing the film to be damaged in the early stage of the test and affecting the accuracy of the test results.

[0024] 2. By providing grooves that can change the position of the screw micrometer at both the fixed end and the movable end of the micro-stress adjustable clamp, and by mounting the movable end of the micro-stress adjustable clamp on the slide of the guide rail, the appropriate position can be set according to the films of different lengths and widths, thereby solving the problem that the existing film clamps cannot meet the needs of film materials of different sizes and avoiding the problem that the film clamps cannot be clamped due to different sizes of films.

[0025] 3. Since the piezoelectric motor can still maintain good driving performance in low temperature environments, the design of the piezoelectric motor can replace the servo motor used as the power source to provide tensile force in most fixtures, avoiding damage to the servo motor under low temperature conditions, which reduces the reliability and stability of the entire test system.

[0026] 4. In low-temperature environments, piezoelectric motors have higher displacement resolution than servo motors, can achieve precise motion control under low-temperature conditions, and can observe micro-scale changes in film stretching.

[0027] 5. By installing a displacement sensor on the slide, not only can displacement detection be achieved, but when the film stretch exceeds the preset displacement, the displacement sensor acts as a limit switch, sending an opposite signal to the central control power supply, causing the piezoelectric motor to move in the opposite direction, achieving repeated stretching of the film. The slide can be freely moved, eliminating the need for repeated installation and removal of the displacement sensor for different film lengths and different stretching lengths. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the overall structure of a preferred embodiment of the low-temperature piezoelectric tensile testing device with precise micro-stress control controlled by piezoelectricity according to the present invention;

[0029] Figure 2 This is an overall schematic diagram of the fixed end of the micro-stress clamp of the present invention;

[0030] Figure 3 for Figure 2 Side view shown;

[0031] Figure 4 for Figure 2 The cross-sectional view shown;

[0032] Figure 5 This is an overall schematic diagram of the movable end of the micro-stress fixture of the present invention;

[0033] Figure 6 for Figure 5 The cross-sectional view shown;

[0034] Figure 7 is a schematic diagram of the piezoelectric motor according to the present invention;

[0035] In the figure: 101, first micrometer screw; 102, first extrusion plate; 103, bolt; 104, first clamping silver rod; 105, first circular clamp base; 106, first trapezoidal clamping plate; 107, circular fixing platform; 108, second micrometer screw; 109, first shaft; 110, nut; 111, screw; 112, first spring; 113, second spring; 114, first toothed boss; 115, bolt; 116, bearing; 117, groove; 118, nut; 119, thread groove;

[0036] 201, third micrometer screw; 202, movable slide; 203, third spring; 204, spring slot; 205, resistance tester wire; 206, resistance tester; 207, first bolt; 208, fourth micrometer screw; 209, second extrusion plate; 210, second bolt; 211, second circular clamp base; 212, second shaft; 213, second trapezoidal clamping plate; 214, trapezoidal plate; 215, second toothed boss; 216, second silver clamping rod;

[0037] 300, piezoelectric drive part; 301, V-shaped beam; 302, drive beam; 303, piezoelectric ring; 304, motor body; 305, weak spring; 306, screw; 307, motor support frame; 308, screw;

[0038] 401, first linear guide rail; 402, second linear guide rail; 403, first guide rail slide; 404, second guide rail slide; 405, third guide rail slide; 406, displacement sensor. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0040] Figure 1 This is a structural diagram of a low-temperature piezoelectric tensile testing device with precise micro-stress control according to the present invention. Figure 2 The fixed end of the micro stress adjustable fixture is shown. Figure 5 Micro stress adjustable fixture movable end, Figure 7 It consists of a piezoelectric motor, dual guide rails, a resistance detector, and a displacement sensor 406.

[0041] Figure 2 The fixed end of the micro-stress adjustable fixture includes: a first micrometer screw 101, a second micrometer screw 108, a first extrusion plate 102, a first clamping silver rod 104, a first circular fixture base 105, a first trapezoidal clamping plate 106, and a circular fixing platform 107. The specific connection relationship is:

[0042] The first extrusion plate 102 is in an inverted U shape and consists of a top plate and a side plate. It is clamped by bolts 103 on the top plate to achieve vertical fixation. The first shaft 109 with threads at both ends passes through the two side plates of the first extrusion plate 102 and is clamped by nuts 110 after being connected to the holes on the first circular clamp bottom plate 105 on both sides. The fixed connection between the first extrusion plate 102 and the first circular clamp bottom plate 105 is achieved by clamping the bolts 103 and the nuts 110.

[0043] Two equally sized, evenly spaced circular holes are located on the bottom of each side wall of the extrusion plate 102, each corresponding to the other. Each hole houses a bearing 116. The outer diameter of each bearing 116 connects to the four circular holes on the bottom of the extrusion plate 102, while the inner diameter connects to the first silver clamping rod 104. This allows the silver clamping rod 104 to be rotatably mounted on the bottom of the extrusion plate 102.

[0044] The first circular clamp bottom plate 105 is U-shaped. Figure 4 , comprising a bottom plate and side plates; a first tooth-shaped boss 114 is produced on the upper surface of the bottom plate, and the first tooth-shaped boss 114 contacts the surface of the first clamping silver rod 104 .

[0045] The first micrometer screw 101 and the second micrometer screw 108 are arranged at the position where the extrusion plate 102 applies stress, and a groove 117 is made at this position to change the position of the micrometer screw. Figure 3 A first spring 112 and a second spring 113 are provided below the groove 117, through which the first micrometer screw 101 and the second micrometer screw 108 pass. Figure 4 The bottom ends of the first micrometer screw 101 and the second micrometer screw 108 are provided with threads, which cooperate with the positions of the thread grooves 119 at the corresponding positions of the bottom plate 105 of the circular clamp.

[0046] like Figure 2The side plates of the circular clamp base plate 105 are connected to the side walls of the trapezoidal clamp 106 by four bolts 115 and nuts 118. The bottom of the trapezoidal clamp 106 is connected to the upper part of the circular fixing platform 107 by screws, and the bottom of the circular fixing platform 107 is connected to the workbench by screws 111.

[0047] Figure 5 The second extrusion plate 209 is connected to the second circular clamp bottom plate 211 through a second shaft 212 with threads on both sides and is clamped by two nuts. There are four evenly distributed circular holes at the bottom of the second extrusion plate 202. The outer diameter of the bearing is connected to the four circular holes at the bottom of the second extrusion plate 209, and the inner diameter is connected to the second clamping silver rod 216. Figure 6 The second tooth-shaped boss 215 is made on the surface of the second circular clamp bottom plate 211 and contacts the surface of the second clamping silver rod 216. The third micrometer 201 and the fourth micrometer 208 are arranged at the position where the second extrusion plate 209 applies stress, and a groove is made at this position to change the position of the micrometer. Figure 6 A third spring 203 through which a third micrometer screw 201 and a fourth micrometer screw 208 pass is provided below the slot. Figure 4 One end of the third micrometer screw 201 and the fourth micrometer screw 208 is threaded and matched with the thread groove at the corresponding position of the second circular clamp bottom plate 211. Figure 5 The second circular clamp base plate 211 is connected to the second trapezoidal clamp plate 213 by four bolts and nuts, the second trapezoidal clamp plate 213 is connected to the first linear guide rail 403 and the second guide rail slide 404 by screws, and the first linear guide rail 403 and the second guide rail slide 404 are respectively slidably connected to the first linear guide rail 401 and the second linear guide rail 402 on the same side.

[0048] The second clamping silver rod 216 is connected to the resistance tester 206 via a wire 205 .

[0049] Figure 7 The piezoelectric drive section 300 shown in the figure has a piezoelectric ring 303 placed on the round end of a drive beam 302 with the same inner diameter. The bottom of the round end of the drive beam 302 is threaded, connecting it to the motor body 304. The triangular end of the drive beam 302 is connected to the V-shaped beam 301 via screws 308. Screws 306 pass through motor support 307 and weak springs 305 to connect to the motor body.

[0050] Working principle: When the present invention is in use, the fixed end of the micro-stress adjustable clamp is first used to roughly clamp one end of the film to be stretched; specifically, the one end of the film to be stretched is placed between the first clamping silver rod 104 and the bottom surface of the first circular clamp base plate 105, and the first micrometer screw 101 and the second micrometer screw 108 are used to perform rotational clamping to achieve rough clamping.

[0051] The other end of the film to be stretched is precisely clamped by using the movable end of the micro-stress adjustable clamp; specifically, the other end of the film to be stretched is placed between the second clamping silver rod 216 and the bottom surface of the second circular clamp base plate 211, and is rotated and clamped by the third micrometer 201 and the second micrometer 208 to achieve precise clamping.

[0052] More specifically, the fixed end of the micro-stress adjustable clamp and the movable end of the micro-stress adjustable clamp are maintained in a horizontal position after the film is fixed.

[0053] The silver rod 216 is connected to the resistance tester 206 via a wire 205. As the pressure contact surface of the silver rod changes, the resistance also changes. The resistance tester 206 accurately measures the stress change through the change in resistance. The principle of micro-stress precision modulation is as follows:

[0054] According to the resistance theorem:

[0055]

[0056] L - length of wire wound into resistor

[0057] S- cross-sectional area of the wire wound into a resistor

[0058] R-resistance value

[0059] And Hooke's law:

[0060] F=-kΔx

[0061] Where k is a constant, the elastic coefficient of the object, Δx is the deformation, and F is the elastic force.

[0062] It is known that the initial length, cross-sectional area, volume and diameter of the clamping silver rod 216 are L0, S0, V0 and d0 respectively.

[0063] The initial resistance is:

[0064]

[0065] Take the case where pressure is applied to the movable end of the micro-stress adjustable fixture as an example:

[0066] The third micrometer screw 201:

[0067] F1=-kΔx1

[0068] Fourth micrometer screw 208:

[0069] F2=-kΔx2

[0070] Since the change in length and cross-sectional area of the clamping silver rod is more sensitive to resistance, we assume that the clamping silver rod is still cylindrical when clamping the film. It can be seen that the resistance of the clamping silver rod changes with the modulation of the micrometer screw, and the changed resistance R1 can be read by the resistance tester 206. Since the initial diameter of the clamping silver rod is d0, when the micrometer screws 201 and 208 are modulated to Δx1 and Δx2 respectively, the diameter of the clamping silver rod is adjusted to d1 = d0 - Δx1 - Δx2, and the area changes to The length is changed to After stress modulation, the resistance becomes

[0071] The relationship between the deformation and the resistance R1 after stress modulation can be derived:

[0072]

[0073] The relationship between microstress and resistance R1 after stress modulation can be derived:

[0074]

[0075] The above is the principle of micro-stress precision modulation.

[0076] Among them, the fixed end and the movable end of the micro-stress adjustable fixture both have slots that can change the position of the screw micrometer, which can avoid the problem that film fixtures of different widths cannot be clamped.

[0077] The piezoelectric drive principle is based on the structure of Langevin oscillators. The longitudinal vibration of two Langevin oscillators creates an elliptical motion trajectory, thereby driving the linear slide to output linear motion. When a DC excitation voltage is applied to the piezoelectric ring 303, the properties of the piezoelectric ceramic material cause the drive beam 302 and the other drive beam to vibrate longitudinally and transversely. Screws 308 connect the drive beam 302 to the V-beam 301. This vibration is transmitted through the V-beam 301 to the contact, forming an elliptical motion trajectory at the contact. This elliptical motion trajectory effectively converts the vibration of the drive beam into linear motion.

[0078] The trapezoidal plate 214 is rigidly connected to the bottom of the second trapezoidal clamping plate 213, and the second trapezoidal clamping plate 213 is connected to the first guide rail slide 403 and the second guide rail slide 404. The piezoelectric motor drives the trapezoidal plate 214 to perform precise linear motion to achieve the film stretching function.

[0079] The displacement detection unit, a displacement sensor 406, is mounted on the third guide rail slide 405 on the first linear guide rail 401. This displacement sensor 406 is connected to a central control power supply to detect displacement. When the piezoelectric drive unit stretches the film, if the film's stretched length exceeds a preset displacement, the displacement sensor acts as a limit switch, sending an opposing signal to the central control power supply, causing the piezoelectric motor to move in the opposite direction, achieving repeated stretching of the film. The slide is also freely movable, eliminating the need for repeated installation and removal of the displacement sensor for different film lengths and different stretching lengths.

[0080] The above embodiments are intended only to illustrate the design concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. The scope of protection of the present invention is not limited to the above embodiments. Therefore, any equivalent changes or modifications made based on the principles and design concepts disclosed in the present invention are within the scope of protection of the present invention.

Claims

1. A low-temperature piezoelectric tensile testing device with precise micro-stress control, characterized in that: include: Linear guides; The fixed end of the micro-stress adjustable clamp is fixedly mounted on one side of the linear guide rail to roughly clamp one end of the film to be stretched; The movable end of the micro-stress adjustable clamp is slidably connected to the linear guide rail to precisely clamp the other end of the film to be stretched; a piezoelectric motor for driving a movable end of a micro-stress adjustable fixture to move along a linear guide rail; a resistance detector electrically connected to the movable end of the micro-stress adjustable fixture; Displacement sensor.

2. A low-temperature piezoelectric tensile testing device with precise micro-stress control according to claim 1, characterized in that: The linear guide rails are provided with two, namely a first linear guide rail (401) and a second linear guide rail (402), which are arranged parallel to each other.

3. The low-temperature piezoelectric tensile testing device with precise micro-stress control according to claim 1, characterized in that: The fixed end of the micro-stress adjustable clamp comprises a first micrometer screw (101), a second micrometer screw (108), a first extrusion plate (102), a first clamping silver rod (104), a first round-shaped clamp bottom plate (105), a first trapezoidal clamp plate (106), and a round-shaped fixing platform (107); wherein the side wall of the first extrusion plate (102) is fixedly connected to the side wall of the first round-shaped clamp bottom plate (105), and the first round-shaped clamp bottom plate (105) is fixed on The first trapezoidal clamping plate (106) is fixed on a circular fixed platform (107); the first micrometer (101) and the second micrometer (108) are arranged on the first extrusion plate (102); the first clamping silver rod (104) is rotatably mounted on the first extrusion plate (102); and the surface of the first circular clamp bottom plate (105) opposite to the bottom of the first clamping silver rod (104) is provided with a first tooth-shaped boss (114).

4. The low-temperature piezoelectric tensile testing device with precise micro-stress control according to claim 1, characterized in that: The movable end of the micro-stress adjustable clamp comprises a third screw micrometer (201), a fourth screw micrometer (208), a second extrusion plate (209), a second clamping silver rod (216), a second circular clamp bottom plate (211), a second trapezoidal clamping plate (213), a trapezoidal plate (214), and a guide rail slide; wherein the side wall of the second extrusion plate (209) is fixedly connected to the side wall of the second circular clamp bottom plate (211), and the second circular clamp bottom plate (211) is fixed on the second trapezoidal clamping plate (213); the second trapezoidal clamping plate (213) is fixedly connected to the second trapezoidal clamping plate (214); 13) is provided with a trapezoidal plate (214), which is kept parallel to the linear guide rail; a third micrometer (201) and a fourth micrometer (208) are provided on the second extrusion plate (209); a second clamping silver rod (216) is rotatably installed on the second extrusion plate (209), and a second tooth-shaped boss (215) is provided on the surface of the second circular clamp base plate (211) opposite to the bottom of the second clamping silver rod (216); both sides of the second trapezoidal clamp plate (213) are slidably connected to the linear guide rail through a guide rail slide.

5. The low-temperature piezoelectric tensile testing device with precise micro-stress control according to claim 1, characterized in that: The resistance detector (206) is mounted on the guide rail slide, and the resistance detector (206) is connected to the second clamping silver rod (216) via a resistance tester lead (205).

6. The low-temperature piezoelectric tensile testing device with precise micro-stress control according to claim 1, characterized in that: The piezoelectric motor is arranged between the linear guide rails and is located below the trapezoidal plate (214).

7. The low-temperature piezoelectric tensile testing device with precise micro-stress control according to claim 1, characterized in that: A displacement sensor (406) is installed on the third guide rail slide (405) on the first linear guide rail (401).

8. The low-temperature piezoelectric tensile testing device with precise micro-stress control according to claim 1, characterized in that: The positions of the screw micrometers on the fixed end and the movable end of the microstress adjustable fixture are adjustable.

9. The low-temperature piezoelectric tensile testing device with precise micro-stress control according to claim 1, characterized in that: A spring is sleeved on the outside of the micrometer screw, and a thread is arranged on the bottom end of the micrometer screw. A thread groove is arranged on the bottom plate of the clip fixture opposite to the micrometer screw.

10. The low-temperature piezoelectric tensile testing device with precise micro-stress control according to claim 1, characterized in that: The piezoelectric motor comprises a piezoelectric ring (303), a driving beam (302), a V-shaped beam (301), a motor support frame (307), and a motor body (304). The piezoelectric ring (303) is placed on the round end of the driving beam (302) having the same inner diameter as the piezoelectric ring (303). The bottom of the round end of the driving beam (302) is provided with a thread and is connected to the motor body (304) through the thread. The triangular end of the driving beam (302) is connected to the V-shaped beam (301), and the motor support frame (307) is connected to the motor body through a weak spring (305).

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