Automatic device for testing and analyzing viscoelasticity of sizing material

Abstract

The utility model discloses an automatic rubber viscoelasticity testing and analyzing device and belongs to the technical field of rubber vulcanization testing. An upper die body and a lower die body of the test host are vertically and oppositely arranged, the upper die body compresses the rubber material test piece, and the lower die body applies shearing force to the rubber material according to a set swing angle and torsion frequency; the input working condition monitor monitors the frequency of inputting shearing force to the rubber material test piece in real time, the output working condition monitor monitors the composite torque borne by the rubber material test piece in the shearing process in real time, and the PLC measurement and control unit is in electric signal connection with the test host, the input working condition monitor and the output working condition monitor. The PLC measurement and control unit is configured to control the upper die body to press a rubber material test piece and control the lower die body to apply shearing force to the pressed rubber material test piece, and the upper computer is in electric signal connection with the PLC measurement and control unit, sends a control instruction to the PLC measurement and control unit and receives, calculates and analyzes real-time monitoring values of the input working condition monitor and the output working condition monitor.

Description

Technical Field

[0001] The utility model relates to the technical field of rubber vulcanization testing, and particularly provides a measurement and control device for viscoelasticity analysis of a test host based on a PLC. Background Art

[0002] With the rapid development of industrial technologies such as high-speed railways, aerospace, etc., various special rubber materials, especially advanced composite rubber materials, have been widely used. At the same time, the application environment of rubber materials is also developing towards high performance and high functionality, such as extreme conditions like extreme temperatures, high speeds, and vacuums.

[0003] In view of this situation, the requirements for performance testing of rubber materials have also been greatly improved. Currently, traditional rubber vulcanization characteristic tests are usually carried out on a test host. The test of the original torque force, that is, the comprehensive torque including viscoelastic characteristics, is difficult to distinguish the changes in the viscous properties, elastic properties, and loss energy of the rubber compound. For advanced rubber composite materials, the manufacturing process is very complex, and the application environment is mostly high-speed, high-temperature, and multi-interference environments. The traditional comprehensive characteristic parameters and empirical parameters can no longer meet the application requirements, and the demand for viscoelastic parameter indicators of the rubber compound is becoming more and more urgent.

[0004] Due to the limitations of measurement methods and means, conventional test hosts lack the detection of the full-cycle torque signal during the shearing process of the rubber compound and the real-time and accurate analysis of measurement signals. The torque force signal during the swinging shearing process of the test host is the superposition of the fundamental wave of the sine signal and noise, and the signal representing the viscoelastic characteristics of the rubber compound is only the signal at a fixed frequency of the die body swing, that is, it is necessary to accurately extract and analyze the fundamental wave component. Therefore, it is necessary to seek a real-time test method that can extract the fundamental wave sine curve. Summary of the Invention

[0005] Based on this, the utility model provides an automatic device for testing and analyzing the viscoelasticity of rubber compounds to obtain the characteristic parameters of the viscosity, elasticity, and loss factor of the rubber compound in real time, which is helpful for the development of new materials, improvement, and adjustment of rubber compound formulations.

[0006] To achieve the above purpose, in the first aspect, the utility model provides an automatic device for testing and analyzing the viscoelasticity of rubber compounds, including a test host, an input working condition monitor, an output working condition monitor, a PLC measurement and control unit, and a host computer.

[0007] The test host includes an upper die body and a lower die body, a cylinder, and a driving motor. The upper die body and the lower die body are arranged vertically opposite to each other. The cylinder is drivingly connected to the upper die body to press the rubber compound test piece. The driving motor is drivingly connected to the lower die body through a crank-rocker mechanism to drive the lower die body to apply a shearing force to the rubber compound according to a set swinging angle and torsional frequency.

[0008] The input working condition monitor is configured to monitor in real time the shear frequency of the shear force input to the rubber test piece; the output working condition monitor is configured to monitor in real time the composite torque borne by the rubber test piece during the shearing process. The PLC measurement and control unit is electrically connected to the test host, the input working condition monitor and the output working condition monitor, and the PLC measurement and control unit is configured to control the upper die body to press the rubber test piece tightly and the lower die body to apply a shear force to the tightly pressed rubber test piece. The upper computer is electrically connected to the PLC measurement and control unit, and is configured to send control instructions to the PLC measurement and control unit, and receive and calculate and analyze the real-time monitoring values of the input working condition monitor and the output working condition monitor.

[0009] Further, the test host further includes a heating mechanism disposed between the upper die body and the lower die body. The PLC measurement and control unit is electrically connected to the heating mechanism and is configured to control the heating mechanism to heat the rubber test piece during the test.

[0010] Further, the input working condition monitor includes a key phase sensor signal-connected to the PLC measurement and control unit. The key phase sensor is disposed outside the driving motor, and the corresponding detection signal is marked as a signal screw installed on the motor output shaft. During the rotation of the driving motor, the key phase sensor receives the signal of the screw rotating with the eccentric wheel and transmits it to the PLC measurement and control unit, and the PLC measurement and control unit calculates the frequency value of the shear force applied by the driving motor to the rubber according to the screw signal.

[0011] Further, the output working condition monitor includes a torque sensor signal-connected to the PLC measurement and control unit. The torque sensor monitors in real time the shear load of the rubber and transmits it to the PLC measurement and control unit, and the PLC measurement and control unit obtains the composite torque required for rubber elasticity analysis according to the received shear load.

[0012] Further, the torque sensor is a full-bridge resistive strain sensor disposed between the upper die body and the cylinder piston, and is configured to measure the reaction force of the rubber on the upper die body during the rubber shearing process. The PLC measurement and control unit calculates the composite torque required for rubber viscoelasticity analysis according to the reaction force.

[0013] Further, the PLC measurement and control unit is provided with digital input / output ports, analog input ports, RS232 data communication ports and programming ports; the button signals such as start, stop, heating, motor start, and cylinder start of the test host are sent to the PLC measurement and control unit through the digital input ports; the pulse signals for starting the motor of the test host, the switch signals for starting heating and the cylinder, and the key direction sensor signals and other output action commands are sent to the test host through the digital output ports; the torque sensor measures the composite torque value of the rubber compound in real time and is sent to the PLC measurement and control unit through the analog input ports; the upper computer communicates with the computer program in real time through the RS232 data communication port, and the upper computer writes and reads the internal program of the PLC measurement and control unit through the programming port.

[0014] In order to achieve the above object, in a second aspect, a method for testing and analyzing the viscoelasticity of a rubber compound using the automatic device for testing and analyzing the viscoelasticity of a rubber compound includes:

[0015] S10. The PLC measurement and control unit controls the upper die body to press the rubber compound test piece, and controls the lower die body to apply a shear load to the pressed rubber compound test piece.

[0016] S20. The input condition monitor monitors the shear frequency input to the rubber compound test piece in real time, and the output condition monitor monitors the composite torque output by the rubber compound test piece during the shearing process in real time.

[0017] S30. The PLC measurement and control unit receives the shear frequency signal and converts it into a pulse signal, and calculates the pulse frequency and pulse period.

[0018] S40. The PLC measurement and control unit receives the composite torque, obtains the real-time digital signal of the torque through the built-in AD conversion function, and obtains the number of data through the built-in timer interrupt, as the torque original data sequence for the fast Fourier transform.

[0019] S50. Perform a fast Fourier transform on the torque original data sequence collected within a single period, and use the rubber viscoelastic mechanism to measure and analyze to obtain the viscoelastic curve, hysteresis angle curve and characteristic data of the rubber, and calculate the elastic torque, viscous torque and loss factor.

[0020] Further, the key direction sensor monitors the shear load period, performs a timer interrupt on the test host according to the real-time period determined by the key direction sensor, measures the composite torque sequence within one period in real time, uploads the shear load period and the measured composite torque sequence to the upper computer, and the upper computer performs Fourier transform calculation to obtain the viscoelastic parameters and display the curve.

[0021] Furthermore, a Fast Fourier Transform module is set inside the PLC measurement and control unit. According to the shear load cycle monitored by the key phase sensor, the test host is interrupted regularly. The composite torque sequence within a single cycle is measured in real time, input into the Fast Fourier Transform module for Fourier transform calculation, and the viscoelasticity results within each cycle are obtained and uploaded to the upper computer, where the viscoelasticity parameters and curves are displayed in real time.

[0022] Furthermore, the torque sensor monitors and obtains the analog signal of the rubber compound shear reaction force, which is input into the analog input port of the PLC measurement and control unit to obtain the time-domain signal M of the force value within a single cycle at time t. The value of each point in the torque data sequence Mt within a single cycle is Mt(i), where i = 0 to N - 1;

[0023] Perform Fourier transform at time t to obtain the elastic force M1, viscous force M2, composite torque M*, and loss factor Tanδ;

[0024] Compared with the prior art, the technical advantages of a measurement and control system and method for viscoelasticity analysis of a test host based on PLC provided by the present utility model are at least reflected in:

[0025] 1. By installing a torque sensor and a key phase sensor, signals are collected in real time and input into the PLC measurement and control unit. The FFT method is applied for viscoelasticity analysis of the rubber compound, and the characteristic parameters of the viscosity, elasticity, and loss factor of the rubber compound are obtained in real time, solving the technical problem that traditional test hosts only provide a single comprehensive torque, and being applicable to the development and improvement of new materials and the adjustment of rubber compound formulations;

[0026] 2. Combining the viscoelasticity characteristics of the vulcanization process of rubber composites, the provided measurement and control system is set based on a PLC programmable controller to achieve regular interruption control. Fourier transform is performed at a fixed sampling frequency within a whole cycle. By cooperating with the key phase and torque sensors, the viscoelasticity analysis of the rubber compound is simply, effectively, and stably realized, and it is easy to flexibly adjust according to needs;

[0027] 3. The provided test method can test the viscoelasticity characteristic parameters of rubber through the Fourier transform vulcanization test method, and deeply and specifically study the viscosity and elasticity of the rubber compound, as well as characteristic parameters such as stored energy and loss energy, reducing the experimental cycle and realizing the simulation of the application environment of multifunctional materials. It is applicable to both the viscoelasticity test of rubber composite vulcanization and the viscoelasticity characteristic test of other materials with periodic changes;

[0028] 4. The selected data acquisition uses a PLC system integrating analog and digital input and output, which can complete the functions of analog acquisition of the rubber compound torque of the test host and digital acquisition of the motor drive cycle signal, without the need for additional system modules, reducing the structural complexity and effectively reducing the complexity and usage cost of the control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0030] Figure 1 The schematic diagram of the structure principle of the measurement and control system for realizing the viscoelastic analysis of the test host based on PLC is provided;

[0031] Figure 2 Schematic diagram of viscoelastic analysis of rubber vulcanization test within one cycle;

[0032] Figure 3 The flowchart of the provided rubber viscoelasticity test and analysis method is as follows;

[0033] Figure 4 This is the fast Fourier transform signal processing flow chart.

[0034] Description of the accompanying drawings:

[0035] 1-Torque sensor, 2-Upper mold, 3-Rubber test piece, 4-Lower mold, 5-Rocker, 6-Transmission rod, 7-Eccentric wheel, 8-Signal screw, 9-Key direction sensor, 10-Drive motor. DETAILED DESCRIPTION

[0036] The utility model relates to an automated device for testing and analyzing the viscoelasticity of rubber materials, which is suitable for testing the gradual change of the viscoelasticity of rubber materials under certain temperature, pressure and shear frequency, and is particularly suitable for testing the vulcanization characteristics of unvulcanized rubber on a test host.

[0037] After extensive practice and in-depth research, the inventors discovered that the mathematical analysis method, Fourier transform, can be used to convert time-domain signals into frequency-domain signals, thereby obtaining a fundamental frequency signal with the same rotational frequency. The commonly used fast Fourier transform (FFT) method can filter out non-periodic noise from periodic signals to obtain a stable fundamental frequency signal. If the FFT method is used to process the periodic motion state signal in the vulcanization test of rubber in real time and eliminate signal interference other than non-oscillating shear in the vulcanization test, such as bearing and assembly interference, the test accuracy and stability will be greatly improved. Therefore, it is necessary to develop a real-time analysis method for the viscoelasticity of rubber materials based on FFT.

[0038] In addition, the test host measurement and control system needs to have the comprehensive integration function of independent control and data acquisition, and should have outstanding stability and reliability. As a programmable logic controller, PLC has flexible control logic programmability; adopting industrial-level design and manufacturing standards, it has high reliability and stability; supporting a variety of input and output modules, it can be conveniently connected and integrated with other devices and systems; more than 90% of the mechanical equipment in industrial enterprises is controlled by PLC, which is the most widely used and popular device control core in industrial enterprises. Therefore, developing a test host measurement and control system based on PLC has good industrial prospects.

[0039] On the basis of the above research, in order to overcome the shortcoming that traditional vulcanization tests only provide a single comprehensive torque, by installing a torque sensor and a key-phase sensor, the signal is collected in real time and input into the PLC measurement and control unit, and the FFT method is applied to analyze the viscoelasticity of the rubber compound. Without changing the original test method, compared with the traditional test host, the characteristic parameters of the viscosity, elasticity and loss factor of the rubber compound can be obtained in real time, which is helpful for the development of new materials, improvement and adjustment of the rubber compound formula.

[0040] The utility model develops a measurement and control system for viscoelasticity analysis of a test host based on PLC, including a rubber vulcanization measurement and control unit built by PLC, and a sensor unit for measuring the torque of the rubber compound and the periodic key-phase signal; the system software mainly includes a fast Fourier algorithm for viscoelasticity analysis of measurement data, and a calculation method for characteristic data of viscous torque, elastic torque, hysteresis angle and modulus; the PLC measurement and control system can be separated from the upper computer, independently complete the acquisition of torque force signals and the basic control functions of the test host, and obtain the conventional measurement data of rubber vulcanization; the viscoelasticity analysis of vulcanized rubber can be realized on the premise of adding the upper computer algorithm, or can be realized by programming in the PLC and then uploaded to the upper computer for display.

[0041] Next, the technical solutions in the embodiments will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present utility model.

[0042] As Figure 1 and Figure 3 shown, the present utility model provides an automatic device for testing and analyzing the viscoelasticity of a rubber compound, which includes a test host, an input working condition monitor, an output working condition monitor, a PLC measurement and control unit and an upper computer.

[0043] Among them, the test host includes an upper die body 2, a lower die body 4, a cylinder, and a driving motor 10. The upper die body 2 and the lower die body 4 are arranged vertically opposite to each other. The cylinder is drivingly connected to the upper die body 2 to press the rubber compound test piece 3. The driving motor 10 is drivingly connected to the lower die body 4 through a crank-rocker mechanism to drive the lower die body 4 to apply a shearing force to the rubber compound according to a set swing angle and torsional frequency. <

[0044] Specifically, the test host is a device for realizing the vulcanization test of rubber compounds, which can apply a shear deformation force to the rubber compound test piece at a certain temperature and pressure according to a specified swing angle and torsional frequency. The specific test process is as follows: the cylinder descends and the upper die body 2 presses the rubber compound test piece 3, and the rubber compound test piece 3 is between the lower die body 4 and the upper die body 2; the driving motor 10 drives the lower die body 4 to generate a sinusoidal swing through a crank-rocker mechanism, that is, the driving motor 10 drives the eccentric wheel 7 to rotate. As the crank of the four-bar linkage mechanism, the crank is connected to the transmission rod 6, the transmission rod is connected to the rocker 5, and the rocker 5 is rigidly connected to the lower die body 4 to realize a sinusoidal swing at a fixed frequency.

[0045] The input condition monitor is configured to monitor in real time the shear frequency of the shear force input to the rubber compound test piece 3. The output condition monitor is configured to monitor in real time the composite torque borne by the rubber compound test piece 3 during the shearing process. The PLC measurement and control unit is electrically connected to the test host, the input condition monitor, and the output condition monitor. The PLC measurement and control unit is configured to control the upper die body 2 to press the rubber compound test piece 3, and the lower die body 4 to apply a shear force to the pressed rubber compound test piece 3. The upper computer is electrically connected to the PLC measurement and control unit and is configured to send control instructions to the PLC measurement and control unit, and receive and calculate and analyze the real-time monitoring values of the input condition monitor and the output condition monitor.

[0046] In some preferred embodiments, the test host further includes a heating mechanism disposed between the upper die body 2 and the lower die body 4. The PLC measurement and control unit is electrically connected to the heating mechanism and is configured to control the heating mechanism to heat the rubber compound test piece 3 during the test process.

[0047] In some preferred embodiments, the input condition monitor includes a key-phase sensor 9 signal-connected to the PLC measurement and control unit. The key-phase sensor 9 is disposed outside the driving motor 10, and the corresponding detection signal is marked as a signal screw 8 installed on the motor output shaft. During the rotation of the driving motor 10, the key-phase sensor 9 receives the signal of the screw rotating with the eccentric wheel and transmits it to the PLC measurement and control unit. The PLC measurement and control unit calculates the frequency value of the shear force applied by the driving motor 10 to the rubber compound according to the screw signal.

[0048] In a specific embodiment, the key direction sensor 9 is a capacitive proximity switch mounted on a motor drive system with a periodic rotation function. The detected signal is marked by a protruding signal screw 8, which is mounted on an eccentric wheel 7. The eccentric wheel 7 is mounted on the output shaft of the drive motor 10 and is connected to the lower mold body 4 via a rocker 5 and a transmission rod 6. The key direction sensor 9 receives a signal with each rotation. The key direction sensor 9 is mounted on the motor fixing bracket. A signal screw 8 is mounted on the side of the eccentric wheel 7 as a key phase detection point to obtain a key phase pulse signal. The distance between the key direction sensor 9 and the key phase detection point is always maintained at 1mm to 3mm. The key direction sensor 9 uses external excitation with an excitation voltage of 24V.

[0049] In some preferred embodiments, the output working condition monitor includes a torque sensor 1 connected to the signal of the PLC measurement and control unit. The torque sensor 1 monitors the shear load of the rubber in real time and transmits it to the PLC measurement and control unit. The PLC measurement and control unit obtains the composite torque required for the elastic analysis of the rubber based on the received shear load.

[0050] In practice, the torque sensor 1 is a full-bridge resistance strain gauge, installed in series between the upper mold and the piston rod of the cylinder. It measures the reaction force exerted by the rubber on the upper mold during shearing. The real-time torque of the rubber test piece is the composite torque used in rubber viscoelastic analysis. The torque sensor also uses external excitation at a voltage of 24V.

[0051] In some preferred embodiments, the torque sensor 1 is a full-bridge resistance strain sensor arranged between the upper mold body 2 and the cylinder piston, and is configured to measure the reaction force of the rubber on the upper mold body 2 during the shearing process of the rubber. The PLC measurement and control unit calculates the composite torque required for the viscoelastic analysis of the rubber based on the reaction force.

[0052] In implementation, the PLC measurement and control unit is provided with a digital input / output port, an analog input port, an RS232 data communication port and a programming port; the button signals of the test host such as start, stop, heating, motor start, cylinder start, etc. are transmitted to the PLC measurement and control unit through the digital input port; the output action commands such as the pulse signal of the start motor of the test host, the start heating, the switch signal of the cylinder, the key direction sensor 9 signal, etc. are transmitted to the test host through the digital output port; the torque sensor 1 measures the composite torque value of the rubber material in real time and transmits it to the PLC measurement and control unit through the analog input port; the host computer communicates with the computer program in real time through the RS232 data communication port, and the host computer writes and reads the internal program of the PLC measurement and control unit through the programming port.

[0053] The utility model person's research found that the displacement excitation applied in the vulcanization test (i.e., the shear excitation at a fixed swing frequency of the lower die body) corresponds to the fundamental frequency signal (i.e., the elastic characteristics of the rubber compound), and there is an angular difference in phase. According to the viscoelastic theory, the phase difference between the viscous characteristics and the elastic characteristics is 90°.

[0054] The signal processing flow of the data acquisition device includes: calculating the reciprocating swing frequency of the die body through the key-to-signal, obtaining the torque signal in real time through the PLC analog port and forming an equidistant torque array, and performing a fast Fourier transform on the full-cycle signal to obtain the viscoelastic characteristic parameters of the rubber compound. The characteristic parameters include elastic torque, viscous torque, and loss factor.

[0055] The implementation method for obtaining the viscoelastic characteristic parameters of the rubber compound is as follows: obtaining the torque M in real time through the PLC analog port, that is, obtaining the real-time digital signal of the torque through the built-in AD conversion function, and using the PLC timed interruption to obtain the number of equidistant data as the original data sequence Mt for the fast Fourier transform. Performing a fast Fourier transform on the original data sequence Mt of the torque force collected within a full cycle to obtain the relationships among the elastic torque M1, viscous torque M2, complex torque M*, and loss factor Tanδ, as shown in the appendix Figure 4 .

[0056] As Figure 2 shown, based on the provided automatic device for testing and analyzing the viscoelasticity of rubber compounds, the utility model provides a method for testing and analyzing the viscoelasticity of rubber compounds. The steps include:

[0057] S10. The PLC measurement and control unit controls the upper die body 2 to press the rubber compound test piece 3, and controls the lower die body 4 to apply a shear load to the pressed rubber compound test piece 3;

[0058] S20. The input condition monitor monitors the shear frequency input to the rubber compound test piece 3 in real time, and the output condition monitor monitors the complex torque output by the rubber compound test piece 3 during the shear process in real time;

[0059] S30. The PLC measurement and control unit receives the shear frequency signal and converts it into a pulse signal, and calculates the pulse frequency and pulse period;

[0060] S40. The PLC measurement and control unit receives the complex torque, obtains the real-time digital signal of the torque through the built-in AD conversion function, and uses the built-in timed interruption to obtain the number of data as the original data sequence of the torque for the fast Fourier transform;

[0061] S50. Perform a fast Fourier transform on the original data sequence of the torque collected within a single cycle, and use the viscoelastic mechanism of rubber to measure and analyze to obtain the viscoelastic curve, hysteresis angle curve, and characteristic data of the rubber, and calculate the elastic torque, viscous torque, and loss factor.

[0062] Among them, the key direction sensor 9 monitors the shear load cycle, performs timed interruption of the test host according to the real-time cycle determined by the key direction sensor 9, measures the composite torque sequence within a cycle in real time, uploads the shear load cycle and the measured composite torque sequence to the host computer, and the host computer performs Fourier transform calculation to obtain viscoelastic parameters and display the curve.

[0063] Among them, a fast Fourier transform module is set inside the PLC measurement and control unit, and the shear load cycle is monitored by the key direction sensor 9 to perform a timed interruption of the test host, and the composite torque sequence within a single cycle is measured in real time. The fast Fourier transform module is input to perform Fourier transform calculation to obtain the viscoelastic results within each cycle, which are uploaded to the host computer, and the host computer displays the viscoelastic parameters and curves in real time.

[0064] During the implementation process, the torque sensor 1 monitors and obtains an analog signal of the rubber shear reaction force, which is input into the analog input port of the PLC measurement and control unit to obtain a force value time domain signal M of a single cycle at time t. The value of each point in the torque data sequence Mt within a single cycle is Mt(i), where i=0 to N-1.

[0065] Perform Fourier transform at time t, and obtain the elastic force M1 from formula 1, the viscous force M2 from formula 2, the composite torque M* after Fourier transform from formula 3, and the loss factor Tanδ from formula 4;

[0066] In one embodiment, the specific implementation process is as follows:

[0067] Preparation before viscoelasticity test: Set the temperature and measurement time of the test host, and check the air source pressure of the test host, which should be no less than 0.5 MPa. Then weigh the unvulcanized sample of standard weight, usually 5g±0.5g, and place it between two layers of high-temperature resistant cellophane. Note that the diameter of the cellophane should exceed the diameter of the mold sealing ring to prevent the rubber test piece 3 from sticking to the mold sealing ring.

[0068] Viscoelasticity Test: Place the adhesive test piece 3 with cellophane film inside the lower mold 4. Press the start button, close the upper mold 2, and begin the test. At this point, the drive motor 10 drives the eccentric wheel 7 with a deflection angle of 0.5° (or 1°) and an oscillation frequency of 1.67Hz (cycle 0.6 seconds, 100 rpm), driving the transmission rod 6 and rocker 5, causing the lower mold 4 to oscillate 0.5° (or 1°). The lower mold 4 drives the adhesive test piece 3, generating a shearing force that is transmitted to the upper mold 2 and then to the torque sensor 1.

[0069] Real-time data analysis: The keyway sensor 9 collects the periodic rotation signal of the eccentric wheel 7. The periodic signal is input into the high-speed pulse input port of the PLC through the sensor, and the pulse period of real-time test is obtained in the internal program of the PLC.

[0070] The torque sensor 1 monitors the analog signal of the change value of the reaction force of the rubber compound test piece 3 during shearing. The signal is input into the analog input port of the PLC through the sensor, and the force value time-domain signal Mt of the entire cycle at time t is obtained. The theoretical period of the test host is 0.6 seconds. Taking a sampling interval of 10 milliseconds as an example, the sampling frequency is 100 Hz, and there are 60 force value points in one cycle. The value of each point in the entire cycle torque data sequence Mt is Mt(i), where i = 0 to N - 1 (where N = 60).

[0071] Perform the Fourier transform at time t to realize the viscoelastic analysis of rubber. The elastic force M1 is obtained from formula (1), the viscous force M2 is obtained from formula (2), the composite torque M* after Fourier transform is obtained from formula (3), and the loss factor Tanδ is obtained from formula (4).

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that it is still possible to modify the specific implementation manners of the present invention or perform equivalent replacements for some technical features. As long as it does not depart from the spirit of the technical solutions of the present invention, it should be covered by the scope of the technical solutions claimed in the present invention.

Claims

1. An automated device for testing and analyzing the viscoelasticity of rubber compounds, characterized in that: It includes a test mainframe, an input working condition monitor, an output working condition monitor, a PLC measurement and control unit, and a host computer; The test mainframe includes an upper die body (2) and a lower die body (4), a cylinder, and a driving motor (10). The upper die body (2) and the lower die body (4) are arranged vertically opposite to each other. The cylinder is drivingly connected to the upper die body (2) to compress the rubber compound test piece (3). The driving motor (10) is drivingly connected to the lower die body (4) through a crank-rocker mechanism to drive the lower die body (4) to apply a shear force to the rubber compound according to a set swing angle and torsion frequency; The input working condition monitor is configured to monitor in real time the shear frequency of the shear force input to the rubber compound test piece (3); The output working condition monitor is configured to monitor in real time the composite torque borne by the rubber compound test piece (3) during the shearing process; The PLC measurement and control unit is electrically connected to the test mainframe, the input working condition monitor, and the output working condition monitor. The PLC measurement and control unit is configured to control the upper die body (2) to compress the rubber compound test piece (3), and the lower die body (4) to apply a shear force to the compressed rubber compound test piece (3); The host computer is electrically connected to the PLC measurement and control unit, and is configured to send control commands to the PLC measurement and control unit, and receive and calculate and analyze the real-time monitoring values of the input working condition monitor and the output working condition monitor; The test mainframe further includes a heating mechanism arranged between the upper die body (2) and the lower die body (4). The PLC measurement and control unit is electrically connected to the heating mechanism and is configured to control the heating mechanism to heat the rubber compound test piece (3) during the test; The input working condition monitor includes a keyway sensor (9) signal-connected to the PLC measurement and control unit. The keyway sensor (9) is arranged outside the driving motor (10). The corresponding detection signal is marked as a signal screw (8) installed on the motor output shaft. During the rotation of the driving motor (10), the keyway sensor (9) receives the signal of the screw rotating with the eccentric wheel and transmits it to the PLC measurement and control unit. The PLC measurement and control unit calculates the frequency value of the shear force applied by the driving motor (10) to the rubber compound according to the screw signal.

2. The automated device for testing and analyzing the viscoelasticity of rubber compounds according to claim 1, characterized in that: The output working condition monitor includes a torque sensor (1) signal-connected to the PLC measurement and control unit. The torque sensor (1) monitors the shear load of the rubber compound in real time and transmits it to the PLC measurement and control unit. The PLC measurement and control unit obtains the composite torque required for rubber compound elasticity analysis according to the received shear load.

3. The automated device for testing and analyzing the viscoelasticity of the rubber compound according to claim 2, wherein: The torque sensor (1) is a full-bridge resistive strain sensor arranged between the upper die body (2) and the cylinder piston, and is configured to measure the reaction force of the rubber compound on the upper die body (2) during the shearing process of the rubber compound. The PLC measurement and control unit calculates the composite torque required for rubber compound viscoelasticity analysis according to the reaction force.

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