Temperature control device and temperature control method for rotary bending fatigue test

Abstract

The invention discloses a temperature control device and a temperature control method for a rotary bending fatigue test. The rotating bending fatigue test temperature control device comprises a test platform, the upper surface of the test platform is fixedly connected with a testing machine, the testing machine is provided with a voltage transmission module, the voltage transmission module is wirelessly connected with a voltage reduction device, the voltage reduction device is connected with a temperature control device through a second compensation wire, and the temperature control device is connected with a resistance furnace through a resistance furnace control wire. A through hole is formed in the resistance furnace, the resistance furnace is connected to the testing machine in a sleeving mode, and according to the temperature control method for the rotary bending fatigue test, the temperature is controlled through the temperature control device for the rotary bending fatigue test. The thermocouple can be in direct contact with the sample, and the problems that a rotating bending test thermocouple cannot be in contact with the sample, and accurate temperature control on the test sample is difficult are solved.

Description

Technical Field

[0001] The invention belongs to the technical field of tests applying repeated force or pulsating force, relates to a temperature control device for a rotary bending fatigue test, and also relates to a temperature control method for a rotary bending fatigue test. Background Art

[0002] The rotary bending fatigue test is a key method for evaluating a material's resistance to fatigue failure under alternating bending stresses. This test applies a constant bending load to a specimen while rotating it about its axis, subjecting the specimen's cross-section to alternating bending stresses (cyclically changing from tensile to compressive stresses) until the specimen fractures. This allows the fatigue properties of the material to be studied. When testing materials that operate in high-temperature environments, thermocouples are used to monitor the surface or internal temperature of the specimen in real time to simulate the actual operating environment and ensure the test is conducted under the specified high-temperature conditions.

[0003] Thermocouple temperature control typically involves contacting the sample with a solder point at the front end of the thermocouple to sense the sample's temperature. Rotary bending fatigue testing involves subjecting the sample to a bending moment followed by high-speed rotation. During this test, if the thermocouple is attached to the sample, the high-speed rotation can cause the thermocouple to become entangled with the fixture and the sample, ultimately breaking under the force. Existing techniques typically employ two methods: direct measurement, where the thermocouple hot end directly contacts the sample's working surface. However, this method must be performed with the testing machine stopped. Indirect measurement, where the thermocouple hot end maintains a distance from the working surface, rather than directly contacting it. However, this method requires establishing a relationship between the sample's surface temperature and the temperature displayed by the thermocouple. This relationship requires a new correction for each change in material or sample size, resulting in a significant test workload. Furthermore, this correction can have significant errors, making accurate sample temperature control impossible. Furthermore, this correction can only be effective during the pre-test heat preservation phase. Once the test begins, the sample heats up during high-speed rotation, and accurate temperature control is impossible because the thermocouple cannot contact the sample during this process. Summary of the Invention

[0004] The application aims to provide a rotating bending fatigue test temperature control device and a rotating bending fatigue test temperature control method, and solve the problems in the prior art that the direct measurement method needs to stop working to measure and has low working efficiency, and the indirect measurement method needs to re-establish a correction relationship every time a material or sample size is changed, has large testing workload, and the correction relationship has large error and cannot guarantee accurate temperature control of the sample.

[0005] The technical scheme of the rotating bending fatigue test temperature control device is as follows: a test platform is provided, a testing machine is fixedly connected to the upper surface of the test platform, a voltage transmission module is installed on the testing machine, the voltage transmission module is wirelessly connected to a voltage reduction device, the voltage reduction device is connected to a temperature control device through a second compensation lead wire, the temperature control device is connected to an electric resistance furnace through an electric resistance furnace control line, the electric resistance furnace is provided with a through hole, and the electric resistance furnace is sleeved on the testing machine.

[0006] The application also has the following characteristics: The testing machine comprises a control box fixed to the test platform, a rotating motor is fixed to the side wall of the control box, a rotating main shaft and the voltage transmission module are fixed to the output end of the rotating motor, a main shaft clamp is arranged at the end of the rotating main shaft away from the control box, a connecting column is also fixed to the test platform, a loading shaft is rotatably connected to the connecting column through a ball bearing, the loading shaft is coaxial with the rotating main shaft, and a loading shaft clamp is arranged at the end of the loading shaft close to the rotating main shaft.

[0007] The voltage transmission module comprises a thermocouple fixing base, the thermocouple fixing base is L-shaped, one side of the thermocouple fixing base is fixed to the side wall of the rotating motor and parallel to the rotating main shaft, the length of the one side of the thermocouple fixing base is greater than the length of the rotating main shaft, and the other side of the thermocouple fixing base is directed to the axis of the rotating main shaft, a matching thermocouple fixing cover plate is arranged at the top of the thermocouple fixing base, the thermocouple fixing base and the thermocouple fixing cover plate are jointly provided with an L-shaped mounting groove which is parallel to the thermocouple fixing base, a thermocouple which is matched in shape is mounted in the mounting groove, the working end of the thermocouple protrudes from the thermocouple fixing base, the cold end of the thermocouple is connected to the first compensation lead wire, and the other end of the first compensation lead wire is connected to a signal conditioning circuit.

[0008] The thermocouple is an S-shaped armored thermocouple. The signal conditioning circuit comprises a filter connected to the thermocouple, the filter is sequentially connected to a signal amplifier, an analog-to-digital converter, a second-order filter and an MCU control chip, and the MCU control chip is connected to a signal transmission component.

[0009] The voltage reducing device comprises a power supply, which is connected with an MCU control chip, a digital-analog converter, a voltage follower, a data connector and a second compensation wire in sequence.

[0010] The signal transmitting part and the signal receiving part are wirelessly transmitted through Bluetooth.

[0011] The temperature control device comprises a temperature control meter, and the second compensation wire is connected to the temperature control meter.

[0012] The technical scheme of the temperature control method for the rotating bending fatigue test of the application is to use a rotating bending fatigue test temperature control device, and the specific steps are as follows: Step one, installing a test sample between a rotating main shaft and a loading shaft; Step two, installing a thermocouple into a thermocouple fixing device, so that the working end of the thermocouple contacts the test sample, and the cold end of the thermocouple is connected to a signal conditioning circuit; Step three, installing an electric resistance furnace, and then connecting the electric resistance furnace, the temperature control device and the voltage reducing device in sequence; Step four, turning on the electric resistance furnace, and controlling the temperature of the electric resistance furnace through a voltage transmission module, the voltage reducing device and the temperature control device.

[0013] The application has the following advantages: Firstly, the application can make the thermocouple directly contact the test sample, and changes the problem that the rotating bending test thermocouple cannot contact the test sample, can only control the temperature field, and cannot accurately control the temperature of the test sample.

[0014] Secondly, the application measures the voltage of the thermocouple, and then directly outputs the same voltage to the temperature control meter in the circuit, and obtains the temperature information through wireless transmission, because the original voltage information is transmitted, the measurement method is equivalent to directly connecting the thermocouple to the temperature control meter, can realize the measurement and control of the temperature control meter through wireless transmission, and ensures the accuracy of the temperature.

[0015] Thirdly, the application divides the temperature control into a signal transmitting end, a signal receiving end and a temperature control meter, and since the application has the signal transmitting end and a wireless receiving end, the application performs first temperature compensation through the first compensation wire in the signal transmitting end, performs second temperature compensation through the second compensation wire after outputting the voltage in the signal receiving end, performs two times of compensation, maximally avoids the interference of the room temperature environment on the test, and improves the accuracy of the remote transmission. DETAILED DESCRIPTION

[0016] Figure 1 is a schematic diagram of the overall structure of the application; Figure 2 is a schematic diagram of the overall structure of the application after the electric resistance furnace is installed; Figure 3 is the schematic diagram of the installation of the sample and thermocouple of the present application; Figure 4 is the structural diagram of the rotary motor of the present application; Figure 5 is the schematic diagram of the installation of the loading shaft of the present application; Figure 6 is the schematic diagram of the installation of the loading shaft and the installation shaft of the present application; Figure 7 is the schematic diagram of the fixation of the thermocouple of the present application; Figure 8 is the schematic diagram of the disassembly of the thermocouple and the fixation base of the thermocouple of the present application; Figure 9 is the schematic diagram of the installation of the thermocouple and the fixation base of the thermocouple of the present application; Figure 10 is the schematic diagram of the structure of the fixation cover plate of the thermocouple of the present application; Figure 11 is the schematic diagram of the data connection of the pressure reduction box of the present application; Figure 12 is the schematic diagram of the data connection of the temperature control device of the present application; Figure 13 is the schematic diagram of the installation of the sample of the present application; Figure 14 is the schematic diagram of the fixation of the sample of the present application; Figure 15 is the schematic diagram of the installation of the sample and thermocouple of the present application; Figure 16 is the schematic diagram of the contact of the sample and thermocouple of the present application.

[0017] In the figure: 1, testing machine; 101, control box; 102, rotary motor; 103, rotary main shaft; 1031, main shaft clamp; 104, loading shaft; 1041, loading shaft clamp; 105, connecting column; 106, sample; 2, voltage transmission module; 201, fixation cover plate of thermocouple; 202, fixation base of thermocouple; 203, thermocouple; 204, installation groove; 205, signal conditioning circuit; 3, pressure reduction device; 301, pressure reduction box; 302, data joint; 303, second compensation wire; 4, temperature control device; 401, temperature control meter; 402, control wire of resistance furnace; 5, resistance furnace; 6, testing platform. DETAILED DESCRIPTION

[0018] The following will be described in detail in combination with specific embodiments.

[0019] The temperature control device of the rotary bending fatigue test of the present application, like Figure 1 , Figure 2As shown, it includes a test platform 6, the upper surface of the test platform 6 is fixedly connected to a test machine 1, a voltage transmission module 2 is installed on the test machine 1, the voltage transmission module 2 is wirelessly connected to the step-down device 3, the step-down device 3 is connected to the temperature control device 4 through the second compensation wire 303, the temperature control device 4 is connected to the resistance furnace 5 through the resistance furnace control line 402, the resistance furnace 5 is provided with a through hole, and the resistance furnace 5 is sleeved on the test machine 1.

[0020] like Figure 3 As shown, the test machine 1 includes a control box 101 fixed on the test platform 6, and a rotating motor 102 is fixed to the side wall of the control box 101. Figure 4 As shown, the output end of the rotating motor 102 is fixedly connected to the rotating main shaft 103 and the voltage transmission module 2, as shown in FIG. Figure 5 As shown, a spindle fixture 1031 is provided at one end of the rotating spindle 103 away from the control box 101, and a connecting column 105 is also fixed to the test platform 6. Figure 6 As shown, a loading shaft 104 is rotatably connected to the connecting column 105 via a ball bearing. The loading shaft 104 is coaxial with the rotating main shaft 103 . A loading shaft fixture 1041 is provided at one end of the loading shaft 104 close to the rotating main shaft 103 .

[0021] Voltage transmission module 2 thermocouple fixing base 202, such as Figure 7 As shown, the thermocouple fixing base 202 is L-shaped, one side of which is fixed to the side wall of the rotating motor 102 and parallel to the rotating main shaft 103, and the length is greater than the length of the rotating main shaft 103, and the other side is toward the axis of the rotating main shaft 103. Figure 9 、 Figure 10 As shown, a matching thermocouple fixing cover 201 is provided on the top of the thermocouple fixing base 202. Figure 8 As shown, the thermocouple fixing base 202 and the thermocouple fixing cover 201 are jointly provided with an L-shaped mounting groove 204 in the same direction as the thermocouple fixing base 202, and a thermocouple 203 of matching shape is installed in the mounting groove 204. The end of the thermocouple 203 away from the rotating motor 102 protrudes from the thermocouple fixing base 202, and the end of the thermocouple 203 close to the rotating motor 102 is connected to the first compensation wire, and the other end of the first compensation wire is connected to the signal conditioning circuit 205.

[0022] Thermocouple 203 is an S-type armored thermocouple.

[0023] The signal conditioning circuit 205 includes a filter connected to the thermocouple 203 , the filter is sequentially connected to a signal amplifier, an analog-to-digital converter, a second-order filter and an MCU control chip, and the MCU control chip is connected to a signal transmission component.

[0024] The voltage reducing device 3 includes a power supply, such as Figure 11As shown, the power supply is connected to the MCU control chip, the digital-to-analog converter, the voltage follower, the data connector 302 and the second compensation wire 303 in sequence, and the MCU control chip is connected with the signal receiving component matched with the signal transmission component.

[0025] The signal transmission component and the signal receiving component are wirelessly transmitted through Bluetooth.

[0026] As shown in the figure, Figure 11 The temperature control device 4 includes a temperature control meter 401, the second compensation wire 303 is connected to the temperature control meter 401, and the temperature control meter 401 is connected to the electric resistance furnace 5 through an electric resistance furnace control line 402.

[0027] The temperature control method of the rotating bending fatigue test of the application uses a rotating bending fatigue test temperature control device, and the specific steps are: Step one, as shown in the figure, Figure 13 The sample 106 is installed between the rotating main shaft 103 and the loading shaft 104; Step two, install the thermocouple 203 into the thermocouple fixing device, as shown in the figure, Figure 15 , 16 The working end of the thermocouple 203 contacts the sample 106, and the cold end of the thermocouple 203 contacts the signal conditioning circuit 205; Step three, install the electric resistance furnace 5, and then connect the electric resistance furnace 5, the temperature control device 4 and the voltage reduction device 3 in sequence; Step four, turn on the electric resistance furnace 5, and control the temperature of the electric resistance furnace 5 through the voltage transmission module 2, the voltage reduction device 3 and the temperature control device 4.

[0028] Example one The rotating bending fatigue test temperature control device includes a test platform 6, the upper surface of the test platform 6 is fixedly connected with a testing machine 1, the testing machine 1 is installed with a voltage transmission module 2, the voltage transmission module 2 is wirelessly connected with a voltage reduction device 3, the voltage reduction device 3 is connected with a temperature control device 4 through a second compensation wire 303, the temperature control device 4 is connected with an electric resistance furnace 5 through an electric resistance furnace control line 402, the electric resistance furnace 5 is provided with a through hole, and the electric resistance furnace 5 is sleeved on the testing machine 1.

[0029] Wireline breakage may cause current leakage, equipment short circuit, and even mechanical accidents caused by winding rotating components; wireless transmission has no physical connection, which eliminates such risks from the root, has strong anti-interference ability, can avoid signal loss caused by poor contact in wired transmission, and ensures complete recording of temperature data, which is crucial for fatigue test, and the data integrity directly affects the reliability of the conclusion.

[0030] Example two As shown in the figure, Figure 3 The testing machine 1 includes a control box 101 fixedly connected to the test platform 6, and the control box 101 is fixedly connected with a rotating motor 102 on the side wall,Figure 4 As shown, the output end of the rotary motor 102 is fixed with a rotating main shaft 103 and a voltage transmission module 2, like Figure 5 As shown, the end of the rotating main shaft 103 away from the control box 101 is provided with a main shaft clamp 1031, and a connecting column 105 is also fixed on the test platform 6, like Figure 6 As shown, the connecting column 105 is rotatably connected with a loading shaft 104 through a ball bearing, the loading shaft 104 is coaxial with the rotating main shaft 103, and the loading shaft 104 is provided with a loading shaft clamp 1041 at the end close to the rotating main shaft 103.

[0031] When the thermocouple and the sample rotate synchronously, they remain absolutely relatively stationary and will not produce friction or displacement due to speed difference, solving the problem that the thermocouple may be separated from the surface of the sample due to centrifugal force and vibration when rotating asynchronously, ensuring that the thermocouple is always closely attached to the sample. After the thermocouple and the sample are synchronously fixed, they become a rigid whole, and the mass distribution and the direction of the centrifugal force are consistent, so they will not exert additional torque, bending moment or tension on the sample. During rotation, the motor, bearing and other components inside the equipment will produce electromagnetic interference, but when rotating synchronously, the relative positions of the thermocouple, the transmitter and the interference source are fixed, and the change in interference intensity is regular, which can be pre-compensated by filtering algorithm.

[0032] Example Three The thermocouple fixing base 202 of the voltage transmission module 2, like Figure 7 As shown, the thermocouple fixing base 202 is L-shaped, one side of which is fixed to the side wall of the rotary motor 102 and parallel to the rotating main shaft 103, and the length is greater than the length of the rotating main shaft 103, and the other side is towards the axis of the rotating main shaft 103, like Figure 9 、 Figure 10 As shown, the top of the thermocouple fixing base 202 is provided with a matching thermocouple fixing cover plate 201, like Figure 8 As shown, the thermocouple fixing base 202 and the thermocouple fixing cover plate 201 are jointly provided with an L-shaped mounting groove 204 in the same direction as the thermocouple fixing base 202, and a thermocouple 203 matching in shape is mounted in the mounting groove 204. The end of the thermocouple 203 away from the rotary motor 102 protrudes from the thermocouple fixing base 202, and the end of the thermocouple 203 close to the rotary motor 102 is connected to the first compensation lead, and the other end of the first compensation lead is connected to the signal conditioning circuit 205.

[0033] In fatigue test, the sample will bear alternating bending stress and high-frequency vibration, and the thermocouple is easy to loosen or even separate from the contact point due to vibration, centrifugal force or slight deformation of the sample, causing abnormal temperature signal. The fixing device firmly fixes the thermocouple at the preset contact point through rigid clamping, ensuring that the contact state is always stable regardless of the movement of the sample, and the fixing device can stabilize the pressure in a reasonable range, balancing the needs of heat conduction efficiency and sample protection.

[0034] Embodiment Four The thermocouple 203 is an S-type armored thermocouple.

[0035] The hot electrode of the S-type thermocouple is composed of a noble metal platinum-rhodium alloy and pure platinum, and has a wide temperature measurement range, which can cover the fatigue test scenarios from room temperature to high temperature. The oxidation resistance and chemical stability of the platinum-rhodium alloy can maintain stable thermoelectric properties at high temperatures, ensuring long-term temperature measurement accuracy. In addition, in the rotary bending fatigue test, the high-speed rotation of the sample will generate strong vibration and centrifugal force, and the armored S-type thermocouple is tightly filled with internal magnesium oxide insulation powder through a metal armored tube, forming a rigid overall structure that can withstand high-frequency vibration and ensure that it will not break or loosen during sample rotation and bending deformation.

[0036] Embodiment Five The signal conditioning circuit 205 includes a filter connected with the thermocouple 203, the filter is connected with a signal amplifier, an analog-to-digital converter, a second-order filter and an MCU control chip in sequence, and the MCU control chip is connected with a signal transmission component.

[0037] The signal output by the thermocouple is a weak millivolt thermoelectric potential, which is easily affected by external electromagnetic interference. The front-end filter can filter out interference components higher than the thermocouple signal frequency, avoid noise amplification by subsequent links, purify the signal from the source, and the millivolt signal output by the thermocouple cannot be accurately recognized by the analog-to-digital converter. The signal amplifier can improve the signal-to-noise ratio of the signal by fixed gain to improve the signal amplitude to the voltage level, provide a large enough signal amplitude for the subsequent analog-to-digital converter conversion, reduce quantization error, and the analog-to-digital converter converts the amplified analog signal into a binary digital signal, realizes the digitization of the signal, and lays a foundation for subsequent digital filtering, operation and transmission. The digital signal converted by the analog-to-digital converter may still have quantization noise or high-frequency interference that has not been completely filtered out by the front-end filter, and the second-order filter can further smooth the signal through an algorithm.

[0038] Embodiment Six The voltage reduction device 3 includes a power supply, such as Figure 11 As shown, the power supply is connected with the MCU control chip, the digital-to-analog converter, the voltage follower, the data joint 302 and the second compensation lead 303 in sequence, and the MCU control chip is connected with a signal receiving component matched with the signal transmission component.

[0039] The signal receiving component of the MCU control chip is matched with the signal transmission component of the signal conditioning circuit, can receive front end data in real time, provides basis for the control decision of the MCU control chip, and based on the received real time data, the MCU control chip can adjust the output of the subsequent link to realize closed loop control; the MCU outputs digital signals, while the back end devices such as the temperature controller and the resistance furnace usually need analog voltage signals as control instructions, and need a digital to analog converter to convert the digital control signals of the MCU into continuous analog voltage signals, so as to ensure that the control instructions match the input range of the back end devices, the digital to analog converter of the front stage and the output signal of the MCU can be affected by power fluctuation and digital circuit noise, while the data connector of the back stage and the second compensation wire 303 can introduce load fluctuation due to the change of line length and contact resistance, the voltage follower can block the direct electrical connection between the front stage and the back stage, avoid the influence of the load change of the back stage on the output accuracy of the digital to analog converter of the front stage, and ensure the stability of the output voltage, the second compensation wire 303 is used as the transmission carrier of the control signal, and the material thereof can reduce line resistance loss and electromagnetic interference, so as to ensure that the control signal output from the voltage follower can be accurately transmitted to the temperature controller, and avoid the voltage reduction caused by the resistance of the wire itself.

[0040] Embodiment seven The signal transmitting component and the signal receiving component are wirelessly transmitted through Bluetooth.

[0041] The voltage transmission module 2 needs to rotate with the rotating motor 102, needs to consider the load, and therefore a relatively small Bluetooth transmission module is used, and because the rotating bending fatigue test temperature control device is used for long time test, the Bluetooth module has low power consumption, can meet the demand of one test after being charged by a battery, and can meet the demand of the present application after the battery is replaced after test without being connected to a power supply for charging.

[0042] Embodiment eight As shown in Figure 11 The temperature control device 4 includes a temperature controller 401, the second compensation wire 303 is connected to the temperature controller 401, and the temperature controller 401 is connected to the resistance furnace 5 through a resistance furnace control line 402.

[0043] The temperature controller 401 can be compatible with multiple thermocouple types, matches the graduation number of the thermocouple through internal parameter setting, and eliminates the error caused by the signal difference of different thermocouples. Meanwhile, part of the advanced temperature controller supports program heating function, can simulate the temperature change process in the actual working condition, and is closer to the real use environment of the material.

[0044] The second compensation wire 303 adopts an alloy material same as or equivalent to the material of the thermocouple electrode, can extend the cold end from the wiring end of the temperature control meter to a temperature stable area, offset the influence of the cold end temperature change through the thermoelectric characteristics of the compensation wire itself, ensure that the signal transmitted to the temperature control meter truly reflects the actual temperature of the hot end, and avoid measurement errors caused by cold end fluctuations.

[0045] The heating element of the resistor 5 needs to be connected to strong current when working, and the control signal output by the temperature control meter 401 is weak current. The resistor furnace control 402 is an intermediate connection carrier of strong current and weak current, can realize electrical isolation of the two, avoid damage to the precision circuit in the temperature control meter caused by strong current impact, and prevent the weak current signal of the temperature control meter from being interfered by strong current.

[0046] Embodiment Nine The rotating bending fatigue test temperature control method of the application uses a rotating bending fatigue test temperature control device, and the specific steps are: Step one, installing the sample 106 between the rotating main shaft 103 and the loading shaft 104; Step two, installing the thermocouple 203 into the thermocouple fixing device, so that the working end of the thermocouple 203 contacts the sample 106, and the cold end of the thermocouple 203 is connected to the signal conditioning circuit 205; Step three, installing the resistor furnace 5, and then sequentially connecting the resistor furnace 5, the temperature control device 4 and the voltage reduction device 3; Step four, turning on the resistor furnace 5, and controlling the temperature of the resistor furnace 5 through the voltage transmission module 2, the voltage reduction device 3 and the temperature control device 4.

[0047] The thermocouple directly contacts the surface or the inside of the sample, can directly capture the real temperature of the sample itself, rather than the temperature of the surrounding environment. The material in the rotating bending fatigue test may generate local heat due to internal friction, plastic deformation and other reasons under alternating stress, and the temperature difference with the environment temperature is significant. Direct contact can eliminate environmental interference and ensure that the temperature measurement data reflect the actual thermodynamic state of the sample.

[0048] In the rotating bending test, the sample needs to continuously rotate around the axis. If the thermocouple signal is transmitted in a wired manner, the wire will be wound, pulled or worn due to the rotation of the sample, which not only may be broken to cause signal interruption, but also may exert additional centrifugal force or torque on the sample, interfere with the original bending stress state and damage the accuracy of the test load. The wireless device is small in size and light in weight, can be integrated on the rotating part, and has little influence on the rotation balance of the sample.

Claims

1. Rotary bending fatigue test temperature control device, characterized in that: The invention comprises a test platform (6), wherein the upper surface of the test platform (6) is fixedly connected to a test machine (1), the test machine (1) is installed with a voltage transmission module (2), the voltage transmission module (2) is wirelessly connected to a step-down device (3), the step-down device (3) is connected to a temperature control device (4) via a second compensation wire (303), the temperature control device (4) is connected to a resistance furnace (5) via a resistance furnace control wire (402), the resistance furnace (5) is provided with a through hole, and the resistance furnace (5) is sleeved on the test machine (1).

2. The temperature control device for the rotary bending fatigue test according to claim 1, characterized in that: The testing machine (1) includes a control box (101) fixedly connected to a test platform (6), a rotating motor (102) fixedly connected to a side wall of the control box (101), an output end of the rotating motor (102) fixedly connected to a rotating spindle (103) and a voltage transmission module (2), an end of the rotating spindle (103) away from the control box (101) is provided with a spindle clamp (1031), a connecting column (105) is further fixedly connected to the test platform (6), a loading shaft (104) is rotatably connected to the connecting column (105) via a ball bearing, the loading shaft (104) is coaxial with the rotating spindle (103), and an end of the loading shaft (104) close to the rotating spindle (103) is provided with a loading shaft clamp (1041).

3. The temperature control device for the rotary bending fatigue test according to claim 2, characterized in that: The voltage transmission module (2) has a thermocouple fixing base (202), and the thermocouple fixing base (202) is L-shaped, one side of which is fixed to the side wall of the rotating motor (102) and is parallel to the rotating main shaft (103), and the length is greater than the length of the rotating main shaft (103), and the other side faces the axis of the rotating main shaft (103). A matching thermocouple fixing cover (201) is provided on the top of the thermocouple fixing base (202). The thermocouple fixing base (202) and the thermocouple fixing cover are connected to each other. (201) is jointly provided with an L-shaped installation groove (204) in the same direction as the thermocouple fixing base (202), and a thermocouple (203) of matching shape is installed in the installation groove (204), and the end of the thermocouple (203) away from the rotating motor (102) protrudes from the thermocouple fixing base (202), and the end of the thermocouple (203) close to the rotating motor (102) is connected to the first compensation wire, and the other end of the first compensation wire is connected to the signal conditioning circuit (205).

4. The temperature control device for the rotary bending fatigue test according to claim 3, characterized in that: The thermocouple (203) is an S-type armored thermocouple.

5. The temperature control device for the rotary bending fatigue test according to claim 3, characterized in that: The signal conditioning circuit (205) includes a filter connected to the thermocouple (203), the filter being sequentially connected to a signal amplifier, an analog-to-digital converter, a second-order filter, and an MCU control chip, and the MCU control chip being connected to a signal transmission component.

6. The temperature control device for a rotary bending fatigue test according to claim 5, characterized in that: The voltage reduction device (3) comprises a power supply, which is sequentially connected to an MCU control chip, a digital-to-analog converter, a voltage follower, a data connector (302), and a second compensation wire (303), and the MCU control chip is connected to a signal receiving component that matches the signal transmission component.

7. The temperature control device for a rotary bending fatigue test according to claim 6, characterized in that: The signal transmitting component and the signal receiving component perform wireless transmission via Bluetooth.

8. The temperature control device for a rotary bending fatigue test according to claim 7, characterized in that: The temperature control device (4) includes a temperature control meter (401), the second compensation wire (303) is connected to the temperature control meter (401), and the temperature control meter (401) is connected to the resistance furnace (5) via a resistance furnace control line (402).

9. Rotary bending fatigue test temperature control method, characterized in that: Using the temperature control device for the rotary bending fatigue test according to claim 8, the specific steps are as follows: Step 1: Install the sample (106) between the rotating spindle (103) and the loading shaft (104); Step 2: Install the thermocouple (203) into the thermocouple fixture so that the working end of the thermocouple (203) contacts the sample (106) and the cold end of the thermocouple (203) is connected to the signal conditioning circuit (205); Step 3: Install the resistance furnace (5), and then connect the resistance furnace (5), the temperature control device (4), and the pressure reduction device (3) in sequence; Step 4: Open the resistance furnace (5) and control the temperature of the resistance furnace (5) through the voltage transmission module (2), the voltage reduction device (3) and the temperature control device (4).

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