A thermal protector and a pressure detection device and detection method of a moving spring plate thereof

Abstract

This invention relates to a thermal protector and a pressure detection device and method for its moving spring, belonging to the field of thermal protectors. The invention includes a pin, a cover plate, a moving spring, a bimetallic strip, a stationary pin one, a stationary pin two, a heating element, a stationary pin three, and a base. The two ends of the heating element are welded to stationary pin one and stationary pin two, respectively. One end of the moving spring is electrically connected to stationary pin one, and the other end of the moving spring cooperates with one end of stationary pin three. The other end of stationary pin three is electrically connected to the pin. When the other end of the moving spring contacts the end of stationary pin three, stationary pin two, the heating element, stationary pin one, the moving spring, stationary pin three, and the pin are sequentially connected to form an electrical circuit. Its structural features include: a gasket welded to one end of the moving spring, a moving contact welded to the other end of the moving spring, a protrusion at the center of the moving spring, a stationary contact welded to one end of stationary pin three, and the gasket electrically connected to stationary pin one.

Description

Technical Field

[0001] This invention relates to a thermal protector and its moving spring pressure detection device and detection method, belonging to the field of thermal protectors, and is mainly used for over-temperature rise and over-current protection of refrigeration compressors or other motors. Background Technology

[0002] Current refrigeration compressors are all equipped with a thermal protector, which is mainly used for over-temperature and over-current protection. Existing thermal protectors consist of a pin assembly, a stationary pin assembly, a moving spring assembly, and a heating element assembly, forming a protective circuit that is electrically connected under normal conditions and disconnected under abnormal conditions. The thermal protector has a heating element and a bimetallic strip. When the refrigerator compressor stalls or the voltage becomes unstable, the current increases. When the heat generated by the heating element reaches the set operating temperature of the bimetallic strip, the thermal protector will trip and disconnect the electrical circuit. When the thermal protector reaches the set reset temperature, the bimetallic strip will reset and reconnect the electrical circuit.

[0003] In addition to their physical, chemical, and bending properties, the moving spring in a thermal protector also possesses mechanical properties. After thousands of mechanical up-and-down movements, not only do its physical, chemical, and bending properties change, but its yield strength, i.e., its elastic force, also gradually decreases. When materials meeting the elastic force requirements are needed, this can be calculated using formulas. Calculate (where F represents the bending elastic force N, K represents the bending stiffness coefficient N / m, and δ represents the tensile amount m).

[0004] In existing thermal protectors, the moving reed is usually made of nickel-copper alloy or beryllium-copper alloy. Due to the characteristics of its physical, chemical, and bending properties, the moving reed generates heat when subjected to high current and undergoes thousands or tens of thousands of opening and closing cycles, which alters the physical, chemical, and bending properties of the material.

[0005] by Figure 5 As the physical and bending properties change, the gap 'a' between the moving spring protrusion and the bimetallic strip gradually increases. At this time, the curvature formed by the moving spring changes accordingly, and the yield strength of the moving spring, i.e., the pressure attenuation, decreases. This leads to an increase in the contact resistance between the moving contact and the stationary contact, resulting in increased heat generation and affecting the service life of the contact. When the gap 'a' is greater than the upper limit, the thermal protector will operate asynchronously, i.e., flashover, and become unusable. In severe cases, it may cause the refrigeration compressor to burn out. The moving spring is made of nickel-copper alloy or beryllium copper alloy material, which has low resistance and good conductivity. However, it is easy to have poor soldering or insufficient strength when welding the moving contact and the gasket.

[0006] When a > 0.3 mm, moving spring F < 0.15 N, and the distance between the moving and stationary contacts is too small after the bimetallic strip suddenly jumps due to heating, the contacts close and conduct before the bimetallic strip cools down and resets. This phenomenon is called asynchronous reset. When a < 0.12 mm, moving spring F > 0.4 N, and the moving and stationary contacts separate before the bimetallic strip suddenly jumps due to heating, this phenomenon is called asynchronous operation. Therefore, the control of the gap a and the bending force F is very important. Thus, it is necessary to calculate and accurately control the bending force required by the moving spring through formula.

[0007] Currently, the pressure testing of moving reeds relies on manual testing using a force gauge, which results in large testing errors, inaccurate judgments, and low testing efficiency. Summary of the Invention

[0008] The purpose of this invention is to overcome the above-mentioned deficiencies in the prior art and to provide a thermal protector with a reasonable structural design and a pressure detection device and method for its moving spring.

[0009] The technical solution adopted by this invention to solve the above problems is as follows: The thermal protector includes a pin, a cover plate, a moving spring, a bimetallic strip, a stationary pin 1, a stationary pin 2, a heating element, a stationary pin 3, and a base. The two ends of the heating element are welded to stationary pin 1 and stationary pin 2 respectively. One end of the moving spring is electrically connected to stationary pin 1, and the other end of the moving spring cooperates with one end of stationary pin 3. The other end of stationary pin 3 is electrically connected to the pin. When the other end of the moving spring contacts the end of stationary pin 3, stationary pin 2, the heating element, stationary pin 1, the moving spring, stationary pin 3, and the pin are sequentially connected to form an electrical circuit. Its structural feature is that a gasket is welded to one end of the moving spring, a moving contact is welded to the other end of the moving spring, and a protrusion is provided at the center of the moving spring. The stationary pin... One end of the three is welded with a stationary contact. The pad is electrically connected to the stationary foot. When the moving contact contacts the stationary contact, the moving spring is set in an arc-shaped structure. At this time, a certain gap 'a' is maintained between the protrusion and the bimetallic strip. The gap is 0.3mm ≥ a ≥ 0.12mm, preferably a = 0.15mm. The value of the force generated by the variable when the moving spring forms an arc-shaped structure is the test value of the bending elastic force F. The value of F is in the range of 0.15N-0.4N. The moving spring is made of a multi-layer composite material of copper alloy and stainless steel, such as copper layer + stainless steel layer, copper layer + stainless steel layer + copper layer, stainless steel layer + copper layer + stainless steel layer, or copper alloy layer + stainless steel layer, copper alloy layer + stainless steel layer + copper alloy layer, stainless steel layer + copper alloy layer + stainless steel layer, etc.

[0010] The calculation process for the bending elastic force F is as follows: (Formula 1) Where K represents the bending stiffness coefficient, and δ represents the tensile strength. (Formula 2) Where E represents the elastic modulus, b represents the width of the moving spring, h represents the thickness of the moving spring, and L represents the length of the moving spring.

[0011] Furthermore, the pins are disposed on the cover plate, and the moving spring, bimetallic strip, stationary pin one, stationary pin two, heating element, and stationary pin three are all disposed in the cavity formed by the cover plate and the base.

[0012] Furthermore, the heating element, bimetallic strip, and moving spring are arranged sequentially from bottom to top.

[0013] Furthermore, the movable spring is provided with bent reinforcing edges and positioning ears on both sides.

[0014] Furthermore, another technical objective of the present invention is to provide a pressure detection device for a moving spring.

[0015] The above-mentioned technical objective of the present invention is achieved through the following technical solution.

[0016] A pressure detection device for a movable spring is provided. This device is used to detect the pressure of a movable spring in a thermal protector. Its structural features are as follows: the pressure detection device for the movable spring includes a placement mechanism, a pressing mechanism, and a testing mechanism. The placement mechanism is located below the pressing mechanism and the testing mechanism, and the pressing mechanism and the testing mechanism cooperate with the placement mechanism.

[0017] Furthermore, the placement mechanism includes a placement seat and a cylinder, the placement seat is connected to the piston rod of the cylinder, and a first sensor and a second sensor are installed on the cylinder barrel of the cylinder.

[0018] Furthermore, the pressing mechanism includes a pressing plate and a second cylinder. The pressing plate is connected to the piston rod of the second cylinder, and a third sensor and a fourth sensor are installed on the cylinder barrel of the second cylinder.

[0019] Furthermore, the testing mechanism includes a connecting rod, cylinder three, a force sensor, cylinder four, and a pull rod. The connecting rod is connected to the cylinder barrel of cylinder three, the piston rod of cylinder three is connected to the cylinder barrel of cylinder four, the piston rod of cylinder four is connected to the force sensor, the force sensor is connected to the pull rod, and the pull rod is provided with a slot. Sensors five and six are installed on the cylinder barrel of cylinder three, and sensors seven and eight are installed on the cylinder barrel of cylinder four.

[0020] Furthermore, the pressure detection device of the moving reed is controlled by a control system, which includes a programmable controller and a force measurement and control transmitter. The programmable controller includes a central processing unit, an analog-to-digital converter, an input interface, and an output interface. The force measurement and control transmitter is connected to the analog-to-digital converter, and the analog-to-digital converter, the input interface, and the output interface are all connected to the central processing unit.

[0021] Furthermore, the positive and negative input terminals of the force sensor are respectively connected to the positive and negative excitation voltage terminals of the force measurement and control transmitter, the positive and negative output terminals of the force sensor are respectively connected to the positive and negative signal voltage terminals of the force measurement and control transmitter, and the positive and negative analog signal output terminals of the force measurement and control transmitter are respectively connected to the positive and negative terminals of the analog-to-digital converter. The digital signal after being converted by the analog-to-digital converter is input to the central processing unit. The X0 terminal of the input interface is connected to the third stationary pin of the thermal protector under test, and the second stationary pin of the thermal protector under test is connected to the negative terminal of the DC power supply. The X1-X8 terminals of the input interface are respectively connected to one end of sensor 1, sensor 2, sensor 3, sensor 4, sensor 5, sensor 6, sensor 7, and sensor 8. The other ends of sensor 1, sensor 2, sensor 3, sensor 4, sensor 5, sensor 6, sensor 7, and sensor 8 are all connected to the negative terminal of the DC power supply. The common terminal COM of the input interface is connected to the positive terminal of the DC power supply. The input signal is transmitted to the central processing unit through the input interface. The Y0-Y3 terminals of the output interface are respectively connected to one end of solenoid valve 1, solenoid valve 2, solenoid valve 3, and solenoid valve 4. The other end of solenoid valve 1, solenoid valve 2, solenoid valve 3, and solenoid valve 4 are all connected to the positive terminal of the DC power supply. The negative terminal of the output interface is connected to the negative terminal of the DC power supply. Solenoid valve 1, solenoid valve 2, solenoid valve 3, and solenoid valve 4 are respectively connected to cylinder 1, cylinder 2, cylinder 3, and cylinder 4 through air pipes. The output signal of the central processing unit controls the air path switching of each solenoid valve through the output interface, and the switched air path controls each cylinder to perform the corresponding action.

[0022] Furthermore, another technical objective of the present invention is to provide a detection method for a pressure detection device for a moving reed.

[0023] The above-mentioned technical objective of the present invention is achieved through the following technical solution.

[0024] A detection method for a pressure detection device for a movable reed, characterized in that: the detection method is as follows: S1. Set the range parameters for the dynamic spring force test of the thermal protector, and set the lower limit F1 = 0.15N and the upper limit F2 = 0.4N respectively; S2. Place the thermal protector under test on the placement base. After the test starts, the central processing unit automatically runs the test process according to the program design requirements. First, it checks whether each test action is in the original position through the input interface. The original position signal of cylinder one, i.e., sensor one, has an on signal. The original position signal of cylinder two, i.e., sensor three, has an on signal. The original position signal of cylinder three, i.e., sensor five, has an on signal. The original position signal of cylinder four, i.e., sensor seven, has an on signal. The X0 terminal of the input interface should have an on signal, i.e., the thermal protector under test should be in the closed state. If all positions are in the original position, proceed to the next action. S3. When the output interface is connected to the Y0 terminal control signal, the solenoid valve is energized, and the air circuit control cylinder sends the thermal protector under test to the designated test position. After receiving the delivery signal from the second sensor, the X2 terminal of the input interface will proceed to the next action control. S4. When the output interface is connected to the Y1 terminal control signal, the second solenoid valve is energized, and the second pneumatic control cylinder pushes the pressing plate to the designated position above the placement seat. After the X4 terminal of the input interface receives the pressing signal from the fourth sensor, it will proceed to the next action control. S5. When the output interface is connected to the Y3 terminal control signal, the solenoid valve four is energized, and the air circuit control cylinder four, along with the power sensor and the lever, descends to one side of the moving contact. After receiving the descent signal from sensor number eight, the X8 terminal of the input interface performs the next action control. S6, when the output interface connects to the Y2 terminal control signal, the solenoid valve three is energized, the air circuit control cylinder three drives the cylinder four, the force sensor and the pull rod to move the slot to the inside of the moving contact. After receiving the moving signal from sensor six at the X6 terminal of the input interface, the next action control is performed. S7: When the output interface cuts off the control signal at the Y3 terminal, the solenoid valve four is de-energized, and the pneumatic control cylinder four, along with the power sensor and the pull rod, slowly rises. At this time, the force sensor generates a force sampling electrical signal under force. This signal is transformed and amplified by the force measurement and control transmitter to generate an analog signal proportional to the pressure of the moving spring. Then, it is transformed into a digital signal by the analog-to-digital converter and sent to the central processing unit for processing. When the moving contact separates from the stationary contact, the X0 terminal of the input interface receives the contact disconnection signal. At this time, the data obtained by the central processing unit after processing is the bending elastic force F of the moving spring, which is saved. After receiving the rising to the upper limit signal from the No. 7 sensor, the X7 terminal of the input interface proceeds to the next action control. S8. When the output interface connects to the Y3 terminal control signal, solenoid valve four is energized, and pneumatic control cylinder four lowers the power sensor and pull rod. When the output interface disconnects the Y2 terminal control signal, solenoid valve three is de-energized, and pneumatic control cylinder three drives cylinder four, the force sensor, and the pull rod to move the slot to the outside of the moving contact. When the output interface disconnects the Y3 terminal control signal, solenoid valve four is de-energized, and pneumatic control cylinder four raises the power sensor and pull rod. When the output interface disconnects the Y1 terminal control signal, solenoid valve two is de-energized, and pneumatic control cylinder two raises the pressing plate. When the output interface disconnects the Y0 terminal control signal, solenoid valve one is de-energized, and pneumatic control cylinder one moves the placement seat back. At this time, all test actions have returned to their original positions. After the input interface receives the original position signals from sensor number seven, sensor number five, sensor number three, and sensor number one, the test cycle of one product ends. S9. The central processing unit compares the stored bending elasticity F with the set lower limit value F1 and upper limit value F2 for judgment. If F1 < F < F2, the tested thermal protector is a qualified product; if F < F1 or F > F2, the tested thermal protector is a defective product.

[0025] Compared with the prior art, the present invention has the following advantages: the moving spring in the thermal protector is made of double or multiple layers of copper (or copper alloy) and stainless steel composite processing, which combines the physical, chemical and bending properties of the stainless steel material and the copper alloy material, thereby enhancing the welding strength of the moving contact and the gasket, and strengthening the yield strength of the moving spring. The heating generated by the large current and the curvature change formed by the moving spring after thousands or tens of thousands of opening and closing cycles are reduced.

[0026] In other words, the moving spring of this thermal protector combines the physical, chemical, and bending properties of stainless steel and copper (or copper alloy) materials, thus achieving excellent welding results, meeting rigidity requirements, and improving product lifespan. By replacing manual inspection with pressure testing, production efficiency and accuracy are greatly improved, and problems caused by human error are avoided, while reducing labor costs. Attached Figure Description

[0027] Figure 1 This is a three-dimensional structural diagram of the thermal protector according to an embodiment of the present invention.

[0028] Figure 2 This is a schematic diagram of the internal structure of the thermal protector according to an embodiment of the present invention.

[0029] Figure 3 This is an exploded structural diagram of the thermal protector according to an embodiment of the present invention.

[0030] Figure 4 This is a three-dimensional structural diagram of the moving spring according to an embodiment of the present invention.

[0031] Figure 5This is a cross-sectional structural diagram of the thermal protector according to an embodiment of the present invention.

[0032] Figure 6 This is a three-dimensional structural schematic diagram of the pressure detection device according to an embodiment of the present invention.

[0033] Figure 7 This is a three-dimensional structural diagram of the placement mechanism according to an embodiment of the present invention.

[0034] Figure 8 This is a three-dimensional structural diagram of the pressing mechanism according to an embodiment of the present invention.

[0035] Figure 9 This is a three-dimensional structural diagram of the testing mechanism according to an embodiment of the present invention.

[0036] Figure 10 This is a circuit diagram of the control system according to an embodiment of the present invention.

[0037] In the diagram: Pin 1, Cover plate 2, Moving spring 3, Bimetallic strip 4, Stationary pin 1 5, Stationary pin 2 6, Heating element 7, Stationary pin 3 8, Base 9. 3-1 Pad, 3-2 Moving Contact, 3-3 Raised Point, 3-4 Reinforcing Edge, 3-5 Positioning Ear Static contact 8-1, Placement mechanism A, pressing mechanism B, testing mechanism C, Placement seat A1, cylinder A2, Press plate B1, cylinder B2, Connecting rod C1, cylinder three C2, force sensor C3, cylinder four C4, pull rod C5 Card slot C5-1, Sensor 1 (SQ1), Sensor 2 (SQ2), Sensor 3 (SQ3), Sensor 4 (SQ4), Sensor 5 (SQ5), Sensor 6 (SQ6), Sensor 7 (SQ7), Sensor 8 (SQ8) Programmable Logic Controller (PLC), Force Measurement and Control Transmitter (CK), Central Processing Unit (CPU), Analog-to-Digital Converter (AD), Input Interface (IN), Output Interface (OUT) Solenoid valve 1 FA2, solenoid valve 2 FB2, solenoid valve 3 FC2, solenoid valve 4 FC4. Detailed Implementation

[0038] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The following embodiments are explanations of the present invention, but the present invention is not limited to the following embodiments.

[0039] Example

[0040] See Figures 1 to 10As shown in the accompanying drawings, the structures, proportions, sizes, etc., depicted are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness or purpose of the invention, should still fall within the scope of the disclosed technical content. Furthermore, the use of terms such as "upper," "lower," "left," "right," "middle," and "one" in this specification is merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0041] The thermal protector in this embodiment (such as...) Figures 1-5 As shown), it includes pin 1, cover plate 2, moving spring 3, bimetallic strip 4, stationary foot 1 5, stationary foot 2 6, heating element 7, stationary foot 3 8 and base 9. Pin 1 is set on cover plate 2. Moving spring 3, bimetallic strip 4, stationary foot 1 5, stationary foot 2 6, heating element 7 and stationary foot 3 8 are all set in the cavity formed by cover plate 2 and base 9. Heating element 7, bimetallic strip 4 and moving spring 3 are arranged in order from bottom to top.

[0042] In this embodiment, the two ends of the heating element 7 are welded to stationary foot 5 and stationary foot 6 respectively. One end of the moving spring 3 is electrically connected to stationary foot 5, and the other end of the moving spring 3 is engaged with one end of stationary foot 8. The other end of stationary foot 8 is electrically connected to pin 1. When the other end of the moving spring 3 contacts one end of stationary foot 8, stationary foot 6, heating element 7, stationary foot 5, moving spring 3, stationary foot 8, and pin 1 are connected in sequence to form an electrical circuit.

[0043] In this embodiment, the movable spring 3 has bent reinforcing edges 3-4 and positioning ears 3-5 on both sides. A pad 3-1 is welded to one end of the movable spring 3, and a movable contact 3-2 is welded to the other end. A protrusion 3-3 is provided in the center of the movable spring 3. A stationary contact 8-1 is welded to one end of the stationary foot 3-5. The pad 3-1 is electrically connected to the stationary foot 5. When the movable contact 3-2 contacts the stationary contact 8-1, the movable spring 3 is arranged in an arc-shaped structure. At this time, a certain gap α (0.3 mm) is maintained between the protrusion 3-3 and the bimetallic strip 4. mm≥a≥0.12mm, preferably a=0.15mm. When the moving spring 3 forms an arc-shaped structure, the value of the force generated by the variable is the test value of the bending elastic force F. The value range of F is 0.15N-0.4N. The moving spring 3 is made of multi-layer composite material of copper alloy and stainless steel, that is, copper layer + stainless steel layer, copper layer + stainless steel layer + copper layer, stainless steel layer + copper layer + stainless steel layer, or copper alloy layer + stainless steel layer, copper alloy layer + stainless steel layer + copper alloy layer, stainless steel layer + copper alloy layer + stainless steel layer, etc.

[0044] The calculation process for the bending elastic force F is as follows: (Formula 1) Where K represents the bending stiffness coefficient (N / m), δ represents the tensile amount (m), and 0.0003m ≥ δ ≥ 0.00012m. (Formula 2) Where E represents the elastic modulus GPa, b represents the width of the moving spring m, h represents the thickness of the moving spring m, and L represents the length of the moving spring m.

[0045] In other words, by substituting the known quantities E, b, h, and L into Formula 2, we can obtain K. Then, by substituting the known quantity δ and K obtained from Formula 2 into Formula 1, we can obtain F.

[0046] Example 1: When the moving spring 3 is made of nickel-copper alloy, where E=130GPa, b=0.006m, h=0.00015m, L=0.022m, and δ=0.0003m, then a=0.12mm, meaning the moving spring 3 undergoes maximum deformation, and the gap a is at its minimum. F = 0.298N (which fits the range of F: 0.15N-0.4N) Example 2: When the moving spring 3 is made of stainless steel alloy, where E=200GPa, b=0.006m, h=0.00015m, L=0.022m, and δ=0.0003m, then a=0.12mm, meaning the moving spring 3 undergoes maximum deformation, and the gap a is at its minimum. F = 0.458N (This does not meet the range of F values, which is 0.15N-0.4N). Example 3: When the moving spring 3 is made of a composite material of stainless steel alloy and copper alloy, where E=170GPa, b=0.006m, h=0.00015m, L=0.022m, and δ=0.0003m, then a=0.12mm, meaning the moving spring 3 undergoes maximum deformation, and the gap a is at its minimum. F = 0.389N (which fits the range of F: 0.15N-0.4N) In the above example, after thousands of up-and-down mechanical movements, the tensile amount δ decreases, causing the bending elastic force F to decrease. When the tensile amount δ decreases to 0.00012 m (i.e., the moving spring 3 undergoes minimum deformation, at which point the gap a is at its maximum), the bending elastic force F is 0.119 N when using a nickel-copper alloy material (which does not meet the value range of 0.15 N-0.4 N), 0.183 N when using a stainless steel alloy material (which meets the value range of 0.15 N-0.4 N), and 0.155 N when using a stainless steel alloy and copper alloy composite material (which meets the value range of 0.15 N-0.4 N). Therefore, when the tensile amount δ of the stainless steel alloy and nickel-copper alloy composite material decreases from 0.0003 m to 0.00012 m, it meets the value range of 0.15 N-0.4 N. Compared with nickel-copper alloy and stainless steel alloy materials, it better meets the elastic force control requirements, improves the welding process strength, and further enhances product quality and lifespan.

[0047] Specifically, the thermal protector is connected to the compressor via the compressor's three-core terminal block. Simply insert pin 1 into the compressor's three-core terminal block; at the same time, the connecting tab of stationary pin 2 6 is used for power connection; after inserting the starter into the compressor's three-core terminal block and making electrical connection, it can be put into normal use. When the mains voltage is too high or too low or when the refrigeration system malfunctions, the bimetallic strip 44 deforms due to heat, pushing the contact of the moving spring 3 away from the contact of stationary pin 3 8, and the thermal protector activates, thereby cutting off the above-mentioned protective circuit and protecting the compressor motor.

[0048] The pressure detection device in this embodiment (such as...) Figures 6-10 (As shown) is used to detect the pressure of the moving spring 3 in the thermal protector. The pressure detection device of the moving spring includes a placement mechanism A, a pressing mechanism B and a testing mechanism C. The placement mechanism A is located below the pressing mechanism B and the testing mechanism C, and the pressing mechanism B and the testing mechanism C are both in cooperation with the placement mechanism A.

[0049] In this embodiment, the placement mechanism A includes a placement seat A1 and a cylinder A2. The placement seat A1 is connected to the piston rod of the cylinder A2. Sensor SQ1 and sensor SQ2 are mounted on the cylinder barrel of the cylinder A2. The pressing mechanism B includes a pressing plate B1 and a cylinder B2. The pressing plate B1 is connected to the piston rod of the cylinder B2. Sensor SQ3 and sensor SQ4 are mounted on the cylinder barrel of the cylinder B2. The testing mechanism C includes a connecting rod C1, a cylinder C2, and a force transmitter. The system includes a sensor C3, a cylinder C4, and a tie rod C5. A connecting rod C1 is connected to the cylinder barrel of a cylinder C2. The piston rod of a cylinder C2 is connected to the cylinder barrel of a cylinder C4. The piston rod of a cylinder C4 is connected to a force sensor C3. The force sensor C3 is connected to the tie rod C5. A slot C5-1 is provided on the tie rod C5. Sensors SQ5 (number 5) and SQ6 (number 6) are installed on the cylinder barrel of a cylinder C2. Sensors SQ7 (number 7) and SQ8 (number 8) are installed on the cylinder barrel of a cylinder C4.

[0050] The pressure detection device of the moving reed is controlled by a control system, which includes a programmable logic controller (PLC) (model FP2SH) and a force transmitter (CK) (model TB3K1). The PLC includes a central processing unit (CPU) (model FP2-C2L), an analog-to-digital converter (AD) (model FP2-AD8VI), an input interface (IN) (model FP2-X16D2), and an output interface (OUT) (model FP2-Y16T). The force transmitter (CK) is connected to the AD, and the AD, the input interface (IN), and the output interface (OUT) are all connected to the CPU.

[0051] The positive input terminal I+ and negative input terminal I- of force sensor C3 are connected to the positive excitation voltage terminal EXC+ and negative excitation voltage terminal EXC- of force measurement and control transmitter CK, respectively. The positive output terminal O+ and negative output terminal O- of force sensor C3 are connected to the positive signal voltage terminal SIG+ and negative signal voltage terminal SIG- of force measurement and control transmitter CK, respectively. The positive analog signal output terminal A+ and negative analog signal output terminal A- of force measurement and control transmitter CK are connected to the positive + terminal and negative - terminal of analog-to-digital converter AD, respectively. The digital signal after being converted by analog-to-digital converter AD is input to the central processing unit (CPU).

[0052] The X0 terminal of the input interface IN is connected to pin 3 (8) of the thermal protector RB under test. Pin 2 (6) of the thermal protector RB under test is connected to the negative terminal V- of the DC power supply. The X1-X8 terminals of the input interface IN (i.e., X1, X2, X3, X4, X5, X6, X7, and X8) are respectively connected to one end of sensor SQ1, sensor SQ2, sensor SQ3, sensor SQ4, sensor SQ5, sensor SQ6, sensor SQ7, and sensor SQ8. The other end of sensor SQ1, sensor SQ2, sensor SQ3, sensor SQ4, sensor SQ5, sensor SQ6, sensor SQ7, and sensor SQ8 is connected to the negative terminal V- of the DC power supply. The common terminal COM of the input interface IN is connected to the positive terminal V+ of the DC power supply. The input signal is transmitted to the central processing unit (CPU) through the input interface IN.

[0053] The Y0-Y3 terminals (i.e., Y0, Y1, Y2, and Y3 terminals) of the output interface OUT are respectively connected to one end of solenoid valve FA2, solenoid valve FB2, solenoid valve FC2, and solenoid valve FC4. The other end of solenoid valve FA2, solenoid valve FB2, solenoid valve FC2, and solenoid valve FC4 are all connected to the positive terminal V+ of the DC power supply. The negative terminal - of the output interface OUT is connected to the negative terminal V- of the DC power supply. Solenoid valve FA2, solenoid valve FB2, solenoid valve FC2, and solenoid valve FC4 are respectively connected to cylinder A2, cylinder B2, cylinder C2, and cylinder C4 through air pipes. The output signal of the central processing unit (CPU) controls the air path switching of each solenoid valve through the output interface OUT, and the switched air path controls each cylinder to perform the corresponding action.

[0054] The testing method for the pressure detection device is as follows: S1. Set the range parameters for the force test of the moving spring 3 of the thermal protector, and set the lower limit F1 = 0.15N and the upper limit F2 = 0.4N respectively.

[0055] S2. Place the thermal protector RB under test on the placement seat A1. After the test starts, the central processing unit (CPU) automatically runs the test process according to the program design requirements. First, it checks whether each test action is in its original position through the input interface IN. The original position signal of cylinder 1 A2 (i.e., sensor SQ1) should be on, the original position signal of cylinder 2 B2 (i.e., sensor SQ3) should be on, the original position signal of cylinder 3 C2 (i.e., sensor SQ5) should be on, and the original position signal of cylinder 4 C4 (i.e., sensor SQ7) should be on. The X0 terminal of the input interface IN should also be on, meaning that the thermal protector RB under test should be in the closed state. If all positions are in their original positions, proceed to the next action.

[0056] S3, when the output interface OUT connects to the control signal at the Y0 terminal, the solenoid valve FA2 is energized, and the air circuit control cylinder A2 sends the thermal protector RB under test to the designated test position. After receiving the signal from the second sensor SQ2 at the X2 terminal of the input interface IN, the next action control is performed.

[0057] S4, when the output interface OUT connects to the control signal at the Y1 terminal, the solenoid valve FB2 is energized, and the air circuit control cylinder B2 pushes the pressing plate B1 to the designated position above the placement seat A1. After the input interface IN receives the pressing signal from sensor SQ4, it proceeds to the next action control.

[0058] S5, when the output interface OUT connects to the control signal at the Y3 terminal, the solenoid valve FC4 is energized, and the pneumatic control cylinder C4, along with the power sensor C3 and the pull rod C5, descends to one side of the moving contact 3-2. After receiving the descent signal from sensor SQ8 at the X8 terminal of the input interface IN, the next action control is performed.

[0059] S6, when the output interface OUT connects to the control signal at the Y2 terminal, the solenoid valve FC2 is energized, and the air circuit control cylinder C2 drives the cylinder C4, force sensor C3 and pull rod C5 to move the slot C5-1 to the inside of the moving contact 3-2. After receiving the move-in signal from sensor SQ6 at the X6 terminal of the input interface IN, the next action control is performed.

[0060] S7, the output interface OUT cuts off the control signal at the Y3 terminal, solenoid valve FC4 is de-energized, and the pneumatic control cylinder C4 slowly rises with the power sensor C3 and the pull rod C5. At this time, the force sensor C3 is subjected to force and generates a force sampling electrical signal. This signal is transformed and amplified by the force measurement and control transmitter CK to generate an analog signal proportional to the pressure of the moving spring. Then, it is transformed into a digital signal by the analog-to-digital converter AD and sent to the central processing unit (CPU) for processing. When the moving contact 3-2 separates from the stationary contact 8-1, the X0 terminal of the input interface IN receives the contact disconnection signal. At this time, the data obtained by the CPU after processing is the bending elastic force F of the moving spring 3, which is saved. After receiving the rising position signal from sensor SQ7 at the X7 terminal of the input interface IN, the next action control is performed.

[0061] S8. When the output interface OUT connects to the Y3 terminal control signal, solenoid valve FC4 is energized, and pneumatic control cylinder C4, along with force sensor C3 and lever C5, descends. When the output interface OUT disconnects the Y2 terminal control signal, solenoid valve FC2 is de-energized, and pneumatic control cylinder C2 drives cylinder C4, force sensor C3, and lever C5 to move slot C5-1 to the outside of moving contact 3-2. When the output interface OUT disconnects the Y3 terminal control signal, solenoid valve FC4 is de-energized, and pneumatic control cylinder C4, along with force sensor C3 and lever C5, descends. As the device rises, the output interface OUT cuts off the control signal at the Y1 end, solenoid valve FB2 is de-energized, and pneumatic control cylinder B2 drives the pressing plate B1 to rise. The output interface OUT cuts off the control signal at the Y0 end, solenoid valve FA2 is de-energized, and pneumatic control cylinder A2 drives the placement seat A1 to retract. At this time, all test actions have returned to their original positions. After the input interface IN receives the original position signals from sensor SQ7, sensor SQ5, sensor SQ3, and sensor SQ1, the test cycle of one product ends.

[0062] S9. The central processing unit (CPU) compares the stored bending elasticity F with the set lower limit value F1 and upper limit value F2 for judgment. If F1 < F < F2, the tested thermal protector RB is a qualified product; if F < F1 or F > F2, the tested thermal protector RB is a defective product.

[0063] Force sensor C3: Samples the pressure signal of the moving reed 3, and converts the force sampling signal into a weak electrical signal, which is then input to the force measurement and control transmitter CK for processing.

[0064] Force measurement and control transmitter CK: The positive terminal EXC+ and negative terminal EXC- of the excitation voltage provide the working power for the force sensor C3. It receives the force sampling electrical signal input by the force sensor C3, performs transformation and amplification processing, and outputs analog signals from the output terminals A+ and A- to the input terminals of the analog-to-digital converter AD.

[0065] Analog-to-digital converter (AD): Converts analog signals into digital signals and sends them to the central processing unit (CPU).

[0066] Input interface IN: Receives switching signals from various sensors and switches and transmits them to the central processing unit (CPU).

[0067] Output interface OUT: Outputs the execution signals of the central processing unit (CPU) to each actuator, which then performs the corresponding actions.

[0068] Central Processing Unit (CPU): The core control component of the control system. Its working principle is to receive input signals from the input interface IN and the analog-to-digital converter AD, perform logic control and data processing according to the program design requirements, and output corresponding control signals at the output interface OUT based on the processing results to realize the control of various functions.

[0069] Solenoid valve FA2: It receives electrical control from the Y0 terminal of the output interface OUT and controls cylinder A2 to perform actions through air circuit switching.

[0070] Solenoid valve FB2: It receives electrical control from the Y1 terminal of the output interface OUT and controls cylinder B2 to perform actions through air circuit switching.

[0071] Solenoid valve FC2: It receives electrical control from the Y2 terminal of the output interface OUT and controls cylinder C2 to perform actions through air circuit switching.

[0072] Solenoid valve FC4: It accepts electrical control from the Y3 terminal of the output interface OUT and controls cylinder C4 to perform actions through air circuit switching.

[0073] Furthermore, it should be noted that the specific embodiments described in this specification may differ in the shape and name of their components, etc. The above description is merely illustrative of the structure of the present invention. All equivalent or simple variations made based on the structure, features, and principles described in this invention are included within the scope of protection of this invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to substitute them, as long as they do not depart from the structure of the invention or exceed the scope defined by the claims, all of which should fall within the scope of protection of this invention.

Claims

1. A pressure detection device for a moving spring in a thermal protector, the pressure detection device for the moving spring (3) in the thermal protector being used to detect the pressure, characterized in that: The pressure detection device for the movable spring includes a placement mechanism (A), a pressing mechanism (B), and a testing mechanism (C). The placement mechanism (A) is located below the pressing mechanism (B) and the testing mechanism (C), and both the pressing mechanism (B) and the testing mechanism (C) cooperate with the placement mechanism (A). The placement mechanism (A) includes a placement seat (A1) and a cylinder (A2). The placement seat (A1) is connected to the piston rod of the cylinder (A2). A sensor (SQ1) and a second sensor (SQ2) are installed on the cylinder barrel of the cylinder (A2). The pressing mechanism (B) includes a pressing plate (B1) and a cylinder two (B2). The pressing plate (B1) is connected to the piston rod of the cylinder two (B2). Sensors No. 3 (SQ3) and No. 4 (SQ4) are installed on the cylinder barrel of the cylinder two (B2). The testing mechanism (C) includes a connecting rod (C1), cylinder three (C2), a force sensor (C3), cylinder four (C4), and a pull rod (C5). The connecting rod (C1) is connected to the cylinder barrel of cylinder three (C2), the piston rod of cylinder three (C2) is connected to the cylinder barrel of cylinder four (C4), the piston rod of cylinder four (C4) is connected to the force sensor (C3), the force sensor (C3) is connected to the pull rod (C5), and the pull rod (C5) is provided with a slot (C5-1). Sensors No. 5 (SQ5) and No. 6 (SQ6) are installed on the cylinder barrel of cylinder three (C2), and sensors No. 7 (SQ7) and No. 8 (SQ8) are installed on the cylinder barrel of cylinder four (C4). The pressure detection device of the moving spring is controlled by a control system, which includes a programmable logic controller (PLC) and a force transmitter (CK). The PLC includes a central processing unit (CPU), an analog-to-digital converter (AD), an input interface (IN), and an output interface (OUT). The force transmitter (CK) is connected to the analog-to-digital converter (AD), and the analog-to-digital converter (AD), the input interface (IN), and the output interface (OUT) are all connected to the central processing unit (CPU). The positive and negative input terminals of the force sensor (C3) are connected to the positive and negative excitation voltage terminals of the force measurement and control transmitter (CK), respectively. The positive and negative output terminals of the force sensor (C3) are connected to the positive and negative signal voltage terminals of the force measurement and control transmitter (CK), respectively. The positive and negative analog signal output terminals of the force measurement and control transmitter (CK) are connected to the positive and negative terminals of the analog-to-digital converter (AD), respectively. The digital signal after being converted by the analog-to-digital converter (AD) is input to the central processing unit (CPU). The X0 terminal of the input interface (IN) is connected to the third (8) stationary pin of the thermal protector (RB) under test, and the second (6) stationary pin of the thermal protector (RB) under test is connected to the negative terminal of the DC power supply. The X1-X8 terminals of the input interface (IN) are respectively connected to one end of sensor 1 (SQ1), sensor 2 (SQ2), sensor 3 (SQ3), sensor 4 (SQ4), sensor 5 (SQ5), sensor 6 (SQ6), sensor 7 (SQ7), and sensor 8 (SQ8). The other end of sensor 1 (SQ1), sensor 2 (SQ2), sensor 3 (SQ3), sensor 4 (SQ4), sensor 5 (SQ5), sensor 6 (SQ6), sensor 7 (SQ7), and sensor 8 (SQ8) are all connected to the negative terminal of the DC power supply. The common terminal COM of the input interface (IN) is connected to the positive terminal of the DC power supply. The input signal is transmitted to the central processing unit (CPU) through the input interface (IN). The Y0-Y3 terminals of the output interface (OUT) are respectively connected to one end of solenoid valve 1 (FA2), solenoid valve 2 (FB2), solenoid valve 3 (FC2), and solenoid valve 4 (FC4). The other end of solenoid valve 1 (FA2), solenoid valve 2 (FB2), solenoid valve 3 (FC2), and solenoid valve 4 (FC4) are all connected to the positive terminal of the DC power supply. The negative terminal of the output interface (OUT) is connected to the negative terminal of the DC power supply. Solenoid valve 1 (FA2), solenoid valve 2 (FB2), solenoid valve 3 (FC2), and solenoid valve 4 (FC4) are respectively connected to cylinder 1 (A2), cylinder 2 (B2), cylinder 3 (C2), and cylinder 4 (C4) through air pipes. The output signal of the central processing unit (CPU) controls the air path switching of each solenoid valve through the output interface (OUT), and the switched air path controls each cylinder to perform the corresponding action. When the force sensor (C3) and the pull rod (C5) rise, the force sensor (C3) generates a force sampling electrical signal. This signal is transformed and amplified by the force measurement and control transmitter (CK) to generate an analog signal proportional to the pressure of the moving spring. Then, it is transformed into a digital signal by the analog-to-digital converter (AD) and sent to the central processing unit (CPU) for processing. When the moving contact (3-2) separates from the stationary contact (8-1), the input interface (IN) of the programmable controller (PLC) receives the contact disconnection signal. At this time, the data obtained by the central processing unit (CPU) after processing is the bending elastic force F of the moving spring (3). The thermal protector includes pins, a cover plate, a moving spring, a bimetallic strip, a stationary foot one, a stationary foot two, a heating element, a stationary foot three, and a base. A pad is welded to one end of the moving spring, and a moving contact is welded to the other end of the moving spring. A protrusion is provided in the center of the moving spring. A stationary contact is welded to one end of the stationary foot three. The pad is electrically connected to the stationary foot one. When the moving contact (3-2) contacts the stationary contact (8-1), the moving spring (3) is arranged in an arc shape. At this time, a gap a is maintained between the protrusion (3-3) and the bimetallic strip (4). The value of the force generated by the variable when the moving spring (3) forms an arc shape is the test value of the bending elastic force F. The moving spring (3) is made of a multi-layer composite material of copper alloy and stainless steel. The calculation process for the bending elastic force F is as follows: Where K represents the bending stiffness coefficient, and δ represents the tensile strength. Where E represents the elastic modulus, b represents the width of the moving spring, h represents the thickness of the moving spring, and L represents the length of the moving spring.

2. The pressure detection device for the moving spring in the thermal protector according to claim 1, characterized in that: The pin (1) is set on the cover plate (2). The moving spring (3), bimetallic strip (4), stationary foot one (5), stationary foot two (6), heating element (7), and stationary foot three (8) are all set in the cavity formed by the cover plate (2) and the base (9). The heating element (7), bimetallic strip (4) and moving spring (3) are arranged sequentially from bottom to top.

3. The pressure detection device for the moving spring in the thermal protector according to claim 1, characterized in that: The two ends of the heating element (7) are welded to stationary foot one (5) and stationary foot two (6) respectively. One end of the moving spring (3) is electrically connected to stationary foot one (5). The other end of the moving spring (3) is matched with one end of stationary foot three (8). The other end of stationary foot three (8) is electrically connected to pin (1). When the other end of the moving spring (3) contacts one end of stationary foot three (8), stationary foot two (6), heating element (7), stationary foot one (5), moving spring (3), stationary foot three (8), and pin (1) are connected in sequence to form an electrical circuit.

4. A detection method for the pressure detection device of the movable spring as described in claim 3, characterized in that: The detection method is as follows: S1. Set the range parameters for the force test of the moving spring (3) of the thermal protector, and set the lower limit F1 = 0.15N and the upper limit F2 = 0.4N respectively; S2. Place the thermal protector (RB) under test on the placement seat (A1). After the test starts, the central processing unit (CPU) will automatically run the test process according to the program design requirements. First, it will check whether each test action is in the original position through the input interface (IN). If each position is in the original position, it will execute the next action. S3. When the output interface (OUT) is connected to the Y0 terminal control signal, the solenoid valve one (FA2) is energized, and the air circuit control cylinder one (A2) sends the thermal protector under test (RB) to the designated test position. After the X2 terminal of the input interface (IN) receives the delivery signal from the second sensor (SQ2), it will proceed to the next action control. S4. When the output interface (OUT) is connected to the control signal at the Y1 end, the second solenoid valve (FB2) is energized, and the second pneumatic control cylinder (B2) pushes the pressing plate (B1) to the designated position above the placement seat (A1). After the X4 end of the input interface (IN) receives the pressing signal from the fourth sensor (SQ4), it proceeds to the next action control. S5, when the output interface (OUT) connects to the control signal at the Y3 terminal, the solenoid valve four (FC4) is energized, and the pneumatic control cylinder four (C4) with the power sensor (C3) and the lever (C5) descends to one side of the moving contact (3-2). After receiving the descent signal from sensor eight (SQ8) at the X8 terminal of the input interface (IN), the next action control is performed. S6, when the output interface (OUT) connects to the control signal at the Y2 terminal, the solenoid valve three (FC2) is energized, and the air circuit control cylinder three (C2) drives cylinder four (C4), force sensor (C3) and pull rod (C5) to move the slot (C5-1) to the inside of the moving contact (3-2). After receiving the move-in signal from sensor six (SQ6) at the X6 terminal of the input interface (IN), the next action control is performed. S7, the output interface (OUT) cuts off the control signal at the Y3 end, the solenoid valve four (FC4) is de-energized, the pneumatic control cylinder four (C4) drives the power sensor (C3) and the pull rod (C5) to rise slowly. At this time, the force sensor (C3) is subjected to force and generates a force sampling electrical signal. This signal is transformed and amplified by the force measurement and control transmitter (CK) to generate an analog signal proportional to the pressure of the moving spring. Then, it is transformed into a digital signal by the analog-to-digital converter (AD) and sent to the central processing unit (CPU) for calculation and processing. When the moving contact (3-2) separates from the stationary contact (8-1), the X0 end of the input interface (IN) receives the contact disconnection signal. At this time, the data obtained by the central processing unit (CPU) after calculation and processing is the bending elastic force F of the moving spring (3), which is saved at the same time. After receiving the rising position signal from the No. 7 sensor (SQ7) at the X7 end of the input interface (IN), the next action control is performed. S8. When the output interface (OUT) connects to the Y3 terminal control signal, solenoid valve four (FC4) is energized, and pneumatic control cylinder four (C4) lowers the force sensor (C3) and pull rod (C5). When the output interface (OUT) disconnects the Y2 terminal control signal, solenoid valve three (FC2) is de-energized, and pneumatic control cylinder three (C2) drives cylinder four (C4), force sensor (C3), and pull rod (C5) to move the slot (C5-1) to the outside of the moving contact (3-2). When the output interface (OUT) disconnects the Y3 terminal control signal, solenoid valve four (FC4) is de-energized, and pneumatic control cylinder four (C4) lowers the force sensor (C3) and pull rod (C5). The lever (C5) rises; the output interface (OUT) cuts off the control signal at the Y1 end, solenoid valve two (FB2) is de-energized, and the pneumatic control cylinder two (B2) drives the pressing plate (B1) to rise; the output interface (OUT) cuts off the control signal at the Y0 end, solenoid valve one (FA2) is de-energized, and the pneumatic control cylinder one (A2) drives the placement seat (A1) to retract. At this time, all test actions have returned to their original positions. After the input interface (IN) receives the original position signals from sensor No. 7 (SQ7), sensor No. 5 (SQ5), sensor No. 3 (SQ3), and sensor No. 1 (SQ1), the test cycle of one product ends. S9. The central processing unit (CPU) compares the stored bending elasticity F with the set lower limit value F1 and upper limit value F2 for judgment. If F1 < F < F2, the tested thermal protector (RB) is a qualified product; if F < F1 or F > F2, the tested thermal protector (RB) is a defective product.

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