Universal tool for temperature limiter counting on-off test

Abstract

The utility model provides a kind of general tool for temperature limiter counting on-off test, it is related to product quality detection technical field, the general tool for temperature limiter counting on-off test includes heating station, cooling station, multiple driving members and main controller;Every driving member is used to install the temperature limiter to be measured, and is used to drive the temperature limiter to be measured reciprocating motion between heating station and cooling station;Main controller is electrically connected with every driving member and every temperature limiter to be measured, for receiving the on-off state signal of every temperature limiter to be measured, and according to every on-off state signal, the on-off counting of corresponding temperature limiter to be measured is carried out independently, and the movement of corresponding driving member is independently controlled.Independent counting is carried out to the state of every temperature limiter to be measured by one main controller, and corresponding driving member is independently controlled, to overcome the problem of low test efficiency, different specifications products cannot be tested simultaneously and single workpiece failure affects overall test.

Description

Technical Field

[0001] This utility model relates to the field of product quality testing technology, and in particular to a universal tooling for testing the on / off state of a temperature limiter. Background Technology

[0002] Thermostats, as critical temperature-sensitive protective components, are widely used in various household appliances and industrial equipment to cut off circuits in case of abnormal temperatures, preventing overheating and damage. To ensure the reliability and safety of thermostats throughout their entire product lifecycle, rigorous durability (lifespan) testing is essential. This testing involves simulating the actual operating conditions of the thermostat, causing it to disconnect at a preset high-temperature point and reset (close) at a preset low-temperature point, repeating this cycle thousands or even tens of thousands of times. Simultaneously, the number of on / off cycles is precisely recorded to verify whether its performance meets design requirements.

[0003] In existing technologies, the life testing of temperature limiters mainly involves the following methods and their problems: The first method is traditional manual testing. Testers manually heat the thermostat using heating equipment (such as a hot air gun), wait for it to disconnect, and then allow it to cool naturally or use simple tools like fans to help it cool until it resets, manually recording the number of times. This method is not only labor-intensive, with extremely long testing cycles and low efficiency, but it is also highly susceptible to human observation and counting errors due to prolonged repetitive operations, leading to poor reliability and consistency of test results. Furthermore, manually operating high-temperature equipment also poses certain safety hazards.

[0004] The second type is a synchronous automated testing device. To improve efficiency, multiple temperature limiters are mounted on the same moving platform. This platform reciprocates between a unified heating and cooling zone, thus enabling batch and synchronous testing of all temperature limiters. However, this synchronous testing mechanism requires all temperature limiters under test to be of the same specification and model, which cannot meet the need to test different types of products with different operating temperatures and lifespan requirements simultaneously. Secondly, the speed of the entire testing process depends on the individual component with the slowest thermal response in the batch, and once a temperature limiter completes its preset number of tests ahead of schedule, it must continue to reciprocate ineffectively with the platform until all components have completed testing, resulting in a waste of time and resources. More importantly, if a single temperature limiter malfunctions or has installation problems, it may affect or even interrupt the testing of the entire batch.

[0005] Therefore, existing temperature limiter testing technology needs to be improved to overcome its shortcomings. Summary of the Invention

[0006] To overcome the problems existing in related technologies, the purpose of this utility model is to provide a universal fixture for testing the on / off state of temperature limiters. This universal fixture for testing the on / off state of temperature limiters is provided by setting up multiple independent driving components, each of which is installed and drives a temperature limiter under test. A main controller independently monitors and counts the state of each temperature limiter under test and independently controls its corresponding driving component. This overcomes the problems of low testing efficiency, inability to test different specifications of products at the same time, poor flexibility, and the impact of a single workpiece failure on the overall test in the existing technology.

[0007] A general-purpose tooling for testing the on / off state of a temperature limiter includes: Heating station and cooling station; Multiple driving components, each of which is used to mount the temperature limiter under test and to drive the temperature limiter under test to reciprocate between the heating station and the cooling station; The main controller is electrically connected to each of the driving components and each of the temperature limiters under test. It is used to receive the on / off status signal of each temperature limiter under test, and to perform independent on / off counting of the corresponding temperature limiter under test according to each on / off status signal, and to independently control the movement of the corresponding driving component.

[0008] Furthermore, it also includes multiple signal conversion circuits; Each of the temperature limiters under test is electrically connected to the main controller through one of the signal conversion circuits; The signal conversion circuit is used to convert the on / off state of the temperature limiter under test into a first control signal that the main controller can receive.

[0009] In actual circuits, the temperature limiter under test operates in a high-voltage AC circuit (e.g., 220V AC), while the input / output (I / O) modules of the main controller (e.g., PLC) operate in a low-voltage DC circuit (e.g., 24V DC). By adding a signal conversion circuit, the high-voltage AC circuit where the temperature limiter is located is isolated and converted from the low-voltage DC circuit where the main controller is located. The high-voltage on / off state generated when the temperature limiter is switched on and off is safely converted into a low-voltage first control signal that conforms to the electrical specifications of the main controller. This achieves effective conversion of high-voltage control signals to low-voltage logic signals, solving the problem of direct connection between circuits of different voltage levels. It ensures that the main controller can accurately read the state of the temperature limiter, achieves electrical isolation, effectively prevents high voltage or circuit surges from damaging the precision main controller, and greatly improves the safety, stability, and service life of the entire testing fixture.

[0010] Furthermore, the signal conversion circuit includes: The first relay, the control terminal of the first relay is connected in series with the corresponding temperature limiter to be tested; The second relay has its control terminal electrically connected to the output of the first relay, and its output terminal electrically connected to the main controller. The second relay is used to output the first control signal to the main controller.

[0011] The temperature limiter under test (TUT) is connected in series to control a first relay. The output of the first relay controls a second relay, and the output of the second relay is then connected to the main controller. Two-stage relays are used for signal transmission and isolation. The first-stage relay directly withstands the high-voltage operating circuit where the TUT is located, achieving the first level of isolation. The second-stage relay then switches the state of the first-stage relay again, providing a cleaner, more voltage-matched switching signal for connection to the main controller, achieving the second level of isolation. Compared to a single switching element, this structure further enhances the protection of the main controller through dual isolation, resulting in higher reliability.

[0012] Furthermore, the first relay is an AC contactor, and the second relay is an intermediate relay.

[0013] AC contactors are specifically designed for controlling AC circuits. Their contacts and coils can operate reliably in a 220V AC environment for extended periods, perfectly matching the operating conditions of temperature limiters. Intermediate relays, on the other hand, are components specifically designed for signal transmission and logic control. Their small size, low power consumption, and fast response make them ideal as interfaces for transmitting signals to PLC inputs. Using AC contactors effectively withstands the arcing and impacts that may occur when the temperature limiter circuit is switched on and off, ensuring the stability of the high-voltage side. Using intermediate relays ensures that the signals provided to the main controller are clean, stable, and interference-free.

[0014] Furthermore, the cooling station includes multiple cooling units, each of which corresponds to one of the driving components; The main controller is electrically connected to each of the cooling units. The main controller is also used to control the operation of the cooling unit corresponding to the driving component according to the on / off state signal, so as to cool the corresponding temperature limiter under test.

[0015] Each cooling unit corresponds one-to-one with a temperature limiter under test (via its drive component), and the main controller can independently control its corresponding cooling unit based on the status of each temperature limiter. This achieves one-to-one configuration and on-demand independent control of the cooling function. When a temperature limiter reaches its high-temperature cutoff point and moves to the cooling station, the main controller only activates its corresponding cooling unit for forced cooling, while the cooling units at other stations remain closed. This significantly improves testing efficiency. The cooling process of each temperature limiter is instantaneous and independent, and its testing cycle is no longer affected by other temperature limiters in the batch. This allows temperature limiters of different specifications and response speeds to be tested in parallel, significantly saving energy. Cooling air (or other cooling media) is supplied to specific stations only when needed, avoiding the huge energy waste caused by continuous or uniform cooling of the entire cooling area.

[0016] Furthermore, each of the cooling units includes: A cooling gas pipeline is provided for connecting to a cooling gas source, and the outlet of the cooling gas pipeline faces the temperature limiter to be tested, which is moved to the cooling station. A solenoid valve, located inside the cooling gas pipeline and electrically connected to the controller, is used to control the connection and disconnection of the cooling gas pipeline and the cooling gas source under the control of the main controller.

[0017] The cooling unit consists of cooling gas pipelines and solenoid valves. The solenoid valves, controlled by the main controller, control the flow of cooling gas in the pipelines. Forced air cooling controlled by the solenoid valves is employed as the cooling method. The main controller can quickly and precisely open or close the solenoid valves with a simple electrical signal, allowing compressed air or other cooling gases to instantly purge the target temperature limiter, removing heat through forced convection heat transfer. This significantly shortens the cooling time in each test cycle, thereby greatly increasing the number of tests per unit time. The solenoid valves have a fast response speed, reliable operation, and long lifespan. Combined with a PLC or other main controller, the logic of the entire independent cooling control can be implemented simply, at low cost, and stably.

[0018] Furthermore, the heating station includes multiple heating units, each of which corresponds to one of the driving components; The main controller is electrically connected to each of the heating units. The main controller is also used to control the operation of the heating unit corresponding to the driving component according to the on / off state signal, so as to heat the corresponding temperature limiter under test.

[0019] The heating station comprises multiple independent heating units, each corresponding to a temperature limiter under test and controlled by the main controller. This breaks down the centralized heating source into multiple independently controllable heating units. Each test station has its own independent heating source, allowing for independent setting and maintenance of its operating temperature. This makes it possible to simultaneously test temperature limiters with different operating temperature specifications on the same equipment; for example, station 1 can test products that break at 85°C, while station 2 can test products that break at 105°C, greatly enhancing the flexibility and applicability of the fixture. Even when testing products of the same specification, the independent heating units can more precisely control the temperature of each station, avoiding uneven thermal fields caused by location differences, thereby improving the consistency of test conditions and the accuracy of test results.

[0020] Furthermore, each of the heating units includes: Heating elements are used to provide the heat required for testing; A temperature sensor is used to monitor the real-time temperature of the heating station; A temperature controller, electrically connected to the temperature sensor, is used to generate a second control signal based on a comparison between the real-time temperature and a preset temperature. The third relay is electrically connected to the temperature controller and the heating element, and is used to receive the second control signal to control the on / off state of the heating element.

[0021] Each heating unit is equipped with a complete closed-loop temperature control system, including a heating element, temperature sensor, temperature controller, and third relay. The temperature controller compares the real-time temperature collected by the temperature sensor with the set target temperature and precisely adjusts the power output of the heating element by controlling the third relay, thereby stabilizing the temperature of each station near the set value. It offloads the complex PID temperature regulation task from the main controller (PLC) to a specialized temperature controller, greatly simplifying the main controller's program logic and making temperature control more professional, faster, and more stable. A precise and stable temperature environment is fundamental to the effectiveness of temperature limiter life testing, directly improving the reliability and repeatability of test results.

[0022] Furthermore, the third relay is a solid-state relay.

[0023] Solid-state relays replace traditional electromagnetic relays to switch the power supply to the heating element. For precise temperature control, the temperature controller sends on / off commands to the relays at an extremely high frequency (sometimes several times per second) to achieve fine-tuning of the heating power. Solid-state relays have no mechanical contacts, resulting in fast switching speeds, no electric arcs, no noise, and an extremely long switching life. They enable very smooth power regulation, minimizing temperature fluctuations. For lifespan testing fixtures requiring tens of thousands of cycles, the number of on / off cycles of the heating control circuit is astronomical. The ultra-long lifespan of solid-state relays ensures the long-term reliability of the temperature control system, avoiding test interruptions or temperature control failures caused by contact adhesion or burning of traditional relays, significantly improving the durability and maintenance-free nature of the fixture.

[0024] Furthermore, it also includes a heating chamber, wherein the heating station is located inside the heating chamber and the cooling station is located outside the heating chamber; The driving component is a cylinder, and each cylinder is used to drive the corresponding temperature limiter under test to extend into the heating chamber, or to drive the corresponding temperature limiter under test to retract outside the heating chamber.

[0025] The heating chamber is physically separated into independent heating and cooling zones, and a cylinder is used as the linear actuator. The heating chamber creates a relatively closed and stable thermal environment, which is conducive to heat accumulation and reduces the impact of ambient temperature fluctuations on the test. Moving the temperature limiter outside the chamber for cooling achieves complete isolation from the heat source, resulting in the fastest cooling effect. This enhances the efficiency and independence of the heating and cooling processes. The stable heating environment inside the chamber improves temperature control accuracy, while thorough external cooling shortens the cycle time. The cylinder drive provides a fast, reliable, and low-cost power source for the reciprocating motion, ensuring that the entire mechanical system can perform tens of thousands of test cycles stably over a long period, providing a solid structural foundation for the high efficiency and high reliability of the entire fixture.

[0026] The beneficial effects of this utility model are as follows: This utility model provides a universal fixture for testing the continuity of temperature limiters. This fixture uses multiple independent driving components, with a main controller independently monitoring, counting, and controlling the motion of each driving component and its corresponding temperature limiter. This independent control architecture allows each testing station to operate without interference, enabling operators to install temperature limiters of different specifications, operating temperatures, and target test counts at different stations and conduct tests simultaneously. This greatly enhances the fixture's versatility and flexibility, meeting the needs of small-batch, diverse testing. Furthermore, because each station counts independently and automatically stops after reaching a preset number of tests, the completed station can promptly replace materials without waiting for other stations with longer testing cycles, effectively avoiding the ineffective use of equipment resources and significantly improving overall testing efficiency and equipment turnover rate. In addition, when the temperature limiter under test in a single station fails or is installed abnormally, the main controller only stops the operation of that station, while other stations can continue to test normally. This avoids the problem of the entire batch of tests being interrupted due to the failure of a single component, thereby significantly improving the stability and reliability of the testing process. Attached Figure Description

[0027] Figure 1 This is a circuit diagram of the temperature control section of a single heating unit provided in the embodiments of this application; Figure 2 This is a circuit schematic diagram of the logic control section provided in the embodiments of this application; Figure 3 This is a side view of the structure of a single test station provided in the embodiments of this application; Figure 4 This is a cross-sectional schematic diagram of the heating box provided in the embodiments of this application; Figure 5 This is a top view of the structure provided in the embodiments of this application, showing multiple test stations arranged side by side.

[0028] Figure label: 100. Cooling gas pipeline; 200. Heating box; 210. Heating ring; 300. Cylinder. Detailed Implementation

[0029] Preferred embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the present invention are shown in the drawings, it should be understood that the present invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art.

[0030] Example 1

[0031] like Figures 1 to 5 As shown, this embodiment provides a universal fixture for testing the on / off state of a temperature limiter, which includes: Heating station and cooling station; Multiple driving components, each of which is used to mount the temperature limiter under test and to drive the temperature limiter under test to reciprocate between the heating station and the cooling station; The main controller is electrically connected to each of the driving components and each of the temperature limiters under test. It is used to receive the on / off status signal of each temperature limiter under test, and to independently count the on / off status of the corresponding temperature limiter under test according to each on / off status signal, and to independently control the movement of the corresponding driving component.

[0032] The fixture is physically divided into a heating station and a cooling station with clearly defined functions. The heating station is used to provide a controllable high-temperature environment to cause the temperature limiter under test to reach its rated disconnection temperature; the cooling station is used to provide a rapid cooling environment to cause the disconnected temperature limiter under test to return to its rated reset (closing) temperature.

[0033] The core of the fixture consists of multiple (e.g., ten) independent drive components. Each drive component is equipped with a dedicated clamp for easy mounting and securing of a temperature limiter under test. These drive components are capable of reciprocating motion and function as actuators to precisely drive the temperature limiter under test mounted on them between the heating and cooling stations.

[0034] The main controller is connected via electrical circuits to the detection circuit of each temperature limiter under test and the control interface of each drive component. This connection enables the main controller to perform two core tasks in parallel and independently: first, to receive the on / off status signal of each temperature limiter under test in real time; and second, to send independent motion control commands to each drive component.

[0035] In traditional synchronous testing devices, all test components are bound to the same actuator, moving forward and backward simultaneously. This limits the testing speed to the slowest component and makes it incompatible with components of different specifications. This embodiment completely breaks this binding relationship by equipping each testing station with an independent drive unit, controlled independently by the main controller. The testing process of each temperature limiter under test is entirely determined by its own performance characteristics, independent of other stations. This not only greatly improves overall testing efficiency but also achieves the versatility of simultaneously testing temperature limiters of different models, operating temperatures, and lifespan requirements.

[0036] The main controller independently receives and processes the on / off status signals of each temperature limiter under test and sets up an independent counter for it. This means that the completion, failure, or need for pause of testing at any station will not affect the normal operation of other stations. For example, if the temperature limiter at station 5 completes 10,000 tests ahead of schedule, the main controller will stop the drive and counting at that station, while station 3 can continue to meet the target of 50,000 tests. This design significantly improves the reliability and intelligence of the tooling, avoiding the risk of the entire batch of tests being scrapped due to the failure of a single component.

[0037] By clearly separating the physical spaces, an optimized environment can be created for the heating and cooling processes. The heating station can be designed as a well-insulated area to achieve stable and efficient heating, while the cooling station can be equipped with powerful cooling methods to achieve rapid cooling. This maximizes the rate of temperature change, thereby greatly shortening the time required for a single on / off cycle.

[0038] Taking one of the testing stations as an example, its complete workflow is as follows: S1. Initialization: Install a temperature limiter to be tested on the corresponding drive unit, and set a target number of tests (e.g., 20,000 times) for the station through the human-machine interface (connected to the main controller).

[0039] S2, Heating Stage: When the test begins, the main controller determines that the temperature limiter is initially in a closed state, and then issues a command to control the movement of the drive components to move the temperature limiter under test to the heating station.

[0040] S3. High-temperature disconnection monitoring: In the heating station, the temperature limiter under test is heated. During this period, the main controller continuously receives its on / off status signal through electrical connection. When the temperature reaches its off point, the internal contacts of the temperature limiter open, the circuit becomes open, and its on / off status signal changes.

[0041] S4, Workstation Switching: Once the main controller receives this "circuit break" signal, it immediately responds and sends a new instruction to the corresponding drive unit, causing it to quickly remove the temperature limiter under test from the heating station and move it to the cooling station.

[0042] S5. Low-temperature reset monitoring: In the cooling station, the temperature limiter under test is rapidly cooled down. The main controller continues to monitor its status. When the temperature drops to its reset point, the internal contacts of the temperature limiter close again, the circuit is restored to a closed circuit, and the on / off status signal changes again.

[0043] S6. Independent counting and loop judgment: Upon receiving the "connection" signal, the main controller determines that a complete "on-off-on" cycle has been completed. It then increments the internal counter specific to that station by 1. Next, the main controller compares the current count with a preset count of 20,000. If the count has not been reached, steps S2 to S6 are repeated to begin the next cycle; if the count has been reached, the main controller stops issuing any commands to the drive unit at that station, and the test at that station is automatically completed and stopped.

[0044] The above process is carried out simultaneously and independently at all activated test stations.

[0045] In addition to the implementation methods mentioned above, this embodiment can also be implemented in the following ways: In this embodiment, the main controller is preferably a programmable logic controller (PLC), which has high reliability and powerful logic programming capabilities in industrial environments. However, in other application scenarios, the main controller can also be an industrial computer (IPC), an embedded system (such as a control board based on ARM or FPGA), or a microcontroller (MCU), as long as it has sufficient multi-channel I / O processing capabilities and parallel logic operation capabilities.

[0046] In this embodiment, the driving component can be a cylinder 300, or an electric push rod driven by a servo motor or stepper motor. This approach allows for more precise control of the movement speed, acceleration, and position. For applications with lighter loads, actuators such as electromagnetic push-pull rods can also be used. The motion is not limited to linear reciprocating motion; it can be circular motion driven by a rotating platform, as long as it enables the switching of the temperature limiter under test between different workstations.

[0047] This embodiment describes a horizontal, in-and-out layout. In space-constrained situations, it can also be designed as a vertical lifting layout (heating at the top and cooling at the bottom or vice versa), or a rotary layout (heating and cooling stations are distributed at different angles on the rotary table).

[0048] Example 2 like Figures 1 to 5 As shown, this embodiment provides a general-purpose fixture for testing the on / off state of a temperature limiter. Based on the general-purpose fixture framework constructed in Embodiment 1, this embodiment focuses on specifying and optimizing the electrical connection interface between the temperature limiter under test and the main controller. Furthermore, this general-purpose fixture for testing the on / off state of a temperature limiter also includes multiple signal conversion circuits; Each of the temperature limiters under test is electrically connected to the main controller through one of the signal conversion circuits; The signal conversion circuit is used to convert the on / off state of the temperature limiter under test into a first control signal that the main controller can receive.

[0049] The signal conversion circuit includes: The first relay, the control terminal of the first relay is connected in series with the corresponding temperature limiter to be tested; The second relay has its control terminal electrically connected to the output of the first relay, and its output terminal electrically connected to the main controller. The second relay is used to output the first control signal to the main controller.

[0050] The first relay is an AC contactor, and the second relay is an intermediate relay.

[0051] In this embodiment, each test station is equipped with an independent signal conversion circuit. For example... Figure 2 As shown, the circuit is physically located between the temperature limiter under test and the main controller.

[0052] In this embodiment, the signal conversion circuit preferably adopts a two-stage relay architecture that is clear in structure and stable and reliable: The first stage is the high-voltage isolation stage. The core of this stage is the first relay, which is selected as an AC contactor in the circuit (e.g., Figure 2 (KM1 to KM10 in the series). The control coil of the AC contactor is connected in series with the corresponding temperature limiter under test, and is connected together between the live wire (L) and neutral wire (N) of the 220V AC power supply to form a high-voltage working circuit.

[0053] The second stage is the signal conversion stage. The core of this stage is the second relay, which is selected as an intermediate relay in the circuit (e.g., ...). Figure 2 (KA1 to KA10 in the diagram). The control coil of the intermediate relay is powered by an independent 24V DC power supply, in which a pair of normally open auxiliary contacts of an AC contactor are connected in series. The output contacts of the intermediate relay (also a pair of normally open contacts) are directly connected to the digital input ports (e.g., X0 to X9) of the main controller (Mitsubishi PLC FX5U).

[0054] The adoption of this two-stage relay architecture, rather than other simpler circuits, is based on a comprehensive consideration of safety, reliability, and maintainability: As a precision electronic device, the main controller's internal chips operate at extremely low voltages and must never come into direct contact with 220V high voltage. By using two physical barriers—an AC contactor and an intermediate relay—and utilizing the magnetic field generated by the coil to drive the contacts to close, complete electrical isolation (or potential isolation) between the high-voltage and low-voltage sides is achieved, fundamentally eliminating the risk of high voltage entering the main controller and causing it to burn out.

[0055] The first stage uses an AC contactor because it is specifically designed for frequent switching of AC loads. It typically incorporates an arc-extinguishing device to effectively suppress the high-voltage arc generated at the moment the temperature limiter contacts open, and can withstand surge currents in the circuit, ensuring stability and long lifespan on the high-voltage side. However, as a power device, the contactor's contact operation may exhibit slight chatter. The second stage uses an intermediate relay because it is a logic element specifically designed for signal transmission. It is sensitive, has a fast response, and minimal contact chatter. It transforms the potentially noisy and coarse switching signal from the AC contactor into a very clean and stable 24V DC switching signal before transmitting it to the main controller, ensuring that every on / off signal received by the main controller is clear and accurate.

[0056] Relays, as standardized industrial components, are relatively inexpensive and easy to replace. With two-stage protection, even in the event of an extreme high-voltage side electrical fault, at most only the upstream AC contactor or the downstream intermediate relay will be damaged, while the expensive main controller I / O module remains unaffected. This makes troubleshooting intuitive and repair / replacement simple and quick, greatly reducing long-term maintenance costs and downtime.

[0057] In this embodiment, the signal transmission process of the signal conversion circuit is as follows: S1. When the temperature limiter is closed: When the internal contacts of the temperature limiter under test are closed, a 220V AC circuit is formed. Current flows through the coil of the AC contactor (KM), causing it to be energized and attracted.

[0058] S2, First signal transmission: After KM is energized, its normally open auxiliary contact closes. This enables the 24V DC circuit to conduct, and current flows through the coil of the intermediate relay (KA), energizing and energizing it.

[0059] S3, Second signal transmission: When KA is energized, its normally open output contact closes. This completes the circuit connected to the main controller input port (e.g., X0), and the X0 port detects a 24V high level. The main controller interprets this state as "on" or "closed" in its program logic.

[0060] S4. When the temperature limiter is disconnected: The internal contacts of the temperature limiter under test open, cutting off the 220V AC circuit. The coil of the AC contactor (KM) is de-energized, and its auxiliary contacts are reset and open under the action of the spring.

[0061] S5, Signal chain interruption: The disconnection of the KM auxiliary contact cuts off the 24V power supply to the intermediate relay (KA) coil, causing KA to de-energize and reset, and its output contacts also disconnect.

[0062] S6, State Change: The loop connected to the main controller input port X0 is broken, and port X0 detects a 0V low level. The main controller interprets this state as "open circuit" or "OFF".

[0063] In addition to the implementation methods mentioned above, this embodiment can also be implemented in the following ways: Mechanical relays can be replaced by optocouplers or solid-state relay modules with integrated optocouplers. The principle is as follows: on the high-voltage side, the on / off state of a temperature limiter controls the illumination of a light-emitting diode (LED); on the low-voltage side, a phototransistor receives the light signal emitted by the LED and converts it into an electrical signal, which is then sent to the main controller. The advantages of this approach are the absence of mechanical contacts, extremely fast response speed, and theoretically unlimited lifespan. The disadvantages are its relatively weak driving capability and higher requirements for surge suppression design in the external circuitry.

[0064] Some high-end PLC models offer dedicated "AC input modules," which integrate the aforementioned opto-isolation and signal conditioning circuits. Using such modules can greatly simplify external wiring. However, their disadvantages include high cost, and a module typically contains multiple input points; if one point fails, the entire module may need to be replaced, making it less flexible and economical than the discrete component solution described in this embodiment.

[0065] A special relay with both a 220VAC coil and 24VDC contact capacity can be used to achieve single-stage switching. However, this would sacrifice the dual protection and signal shaping functions offered by a two-stage solution, and the system's extreme anti-interference capability and reliability would be reduced.

[0066] Example 3 like Figures 1 to 5 As shown, this embodiment provides a universal fixture for testing the on / off state of a thermostat counting device. Based on the universal fixture framework constructed in Embodiment 1, this embodiment elaborates on the internal structure and operation of the cooling station. Furthermore, the cooling station of this universal fixture for testing the on / off state of a thermostat counting device includes multiple cooling units, each cooling unit corresponding to one of the driving components. The main controller is electrically connected to each of the cooling units. The main controller is also used to control the operation of the cooling unit corresponding to the driving component according to the on / off state signal, so as to cool the temperature limiter under test.

[0067] Each of the cooling units includes: Cooling gas pipeline 100, the cooling gas pipeline 100 is connected to a cooling gas source, and the outlet of the cooling gas pipeline 100 faces the temperature limiter to be tested that is moved to the cooling station. A solenoid valve is installed inside the cooling gas pipeline 100 and electrically connected to the controller. It is used to control the connection and disconnection between the cooling gas pipeline 100 and the cooling gas source under the control of the main controller.

[0068] In this embodiment, the cooling station is not a general open area, but an array of multiple highly integrated and independent cooling units. The core of this design is that each cooling unit has a strict one-to-one correspondence with a driving component (and the temperature limiter it carries), ensuring the accuracy of control.

[0069] Specifically, each cooling unit comprises the following two core components: Cooling gas conduit 100 is a specially laid conduit that connects at one end to a centralized cooling gas source (e.g., a compressed air system in a factory) and at the other end to one or more precisely oriented nozzles. The physical positions of these nozzles are carefully designed to ensure that when the drive unit moves the temperature limiter under test to the cooling station, the nozzles are directly facing the critical heat dissipation parts of the temperature limiter under test.

[0070] Solenoid valves, such as Figure 2 As shown in YV1 to YV10, each cooling gas pipe 100 has a solenoid valve installed in series. This solenoid valve is an electrically controlled switch, and its control terminal is electrically connected to an independent output port of the main controller (PLC). The main controller can precisely control the opening and closing of the solenoid valve by outputting a simple switching electrical signal (e.g., 24V DC).

[0071] The physical form of the entire cooling station is that each test channel is equipped with an independently controllable forced air cooling system consisting of solenoid valves and nozzles.

[0072] The adoption of this independent, active cooling unit design, rather than traditional natural cooling or zone fan cooling, is based on the following in-depth considerations: The life test cycle of a temperature limiter consists of alternating heating and cooling processes. In many cases, passive or slow cooling is the bottleneck of the entire test cycle. This design employs a solenoid valve-controlled forced air cooling method, utilizing the principle of forced convection heat transfer, which has a much higher heat dissipation efficiency than natural cooling. This allows the temperature of the temperature limiter under test to drop rapidly to the reset point after disconnection, thereby greatly shortening the single cycle time. When conducting tens of thousands of life tests, this efficiency improvement is exponential.

[0073] Using a single large fan to cool all workstations uniformly makes on-demand control impossible. In this design, however, the main controller can operate only the solenoid valve corresponding to a specific workstation based on its monitored on / off status signal. This means that cooling air is precisely supplied only when needed, to the required object, and for the required time period. This perfectly supports the overall concept of parallel testing of temperature limiters of different specifications and testing processes.

[0074] Compared to a continuously running high-power cooling fan, this solution consumes extremely little energy. Compressed air is only consumed during the few seconds of cooling; for the majority of the remaining time (heating and waiting phases), the solenoid valve remains closed, resulting in virtually no energy waste. This pulsed energy usage pattern gives the tooling significant economic and environmental advantages during long-term operation.

[0075] The working process of the cooling unit in this embodiment is as follows, taking station 5 as an example: S1, Trigger Cooldown: When the main controller detects that the temperature limiter under test at station 5 has changed from a closed circuit to an open circuit, it will immediately execute two parallel actions: S11. Control drive unit 5 to move the temperature limiter from the heating station to the cooling station; S12 outputs a 24V ON signal to the coil of the solenoid valve (YV5) of cooling unit 5.

[0076] S2, Perform cooling: Upon receiving the signal, solenoid valve YV5 opens instantly, and high-pressure cooling gas is immediately ejected from the nozzle through cooling gas pipe 100, directly and forcefully blowing onto the surface of the temperature limiter under test (YV5), causing its temperature to drop rapidly. At this time, all other solenoid valves (YV1-YV4, YV6-YV10) remain closed.

[0077] S3, Stop cooling: While performing cooling, the main controller continuously monitors the status of temperature limiter #5. When its temperature drops to the reset point and its status changes from open circuit to closed circuit, the main controller immediately cancels the ON signal to solenoid valve YV5. The solenoid valve closes due to de-energization, and gas injection stops.

[0078] S4, Standby: The cooling unit then enters standby mode, awaiting the cooling command for the next cycle at this workstation.

[0079] In addition to the implementation methods mentioned above, this embodiment can also be implemented in the following ways: For some precision temperature limiters that are prone to oxidation at high temperatures, the cooling gas source can be replaced by inert gases such as nitrogen (N2) instead of compressed air to provide protection during the cooling process. For extreme tests that require even faster cooling rates, cryogenic gases pre-cooled by refrigeration equipment can even be used.

[0080] While solenoid valves offer simple and reliable on / off control, they can be replaced with proportional valves in certain research and development tests that require simulating specific cooling profiles. By outputting an analog signal (such as 4-20mA) from the main controller, the valve opening can be precisely controlled, thereby regulating the flow rate of cooling gas and achieving programmed control of the cooling rate.

[0081] Besides gas cooling, contact cooling can also be used for certain specially packaged temperature limiters. For example, the cooling station can be designed as a metal heat sink driven by a thermoelectric cooler (TEC) or circulating chilled water. The driving component moves the temperature limiter under test to the cooling station and makes it fit tightly against the heat sink to achieve more efficient heat conduction. In this case, the main controller will control the start and stop of the TEC or chilled water circulation pump.

[0082] Example 4 like Figures 1 to 5 As shown, this embodiment provides a general-purpose fixture for testing the on / off state of a thermostat. Based on the general-purpose fixture framework constructed in Embodiment 1, this embodiment elaborates on the specific technical implementation scheme of its heating station. Furthermore, the heating station of this general-purpose fixture for testing the on / off state of a thermostat includes multiple heating units, each heating unit corresponding to one of the driving components. The main controller is electrically connected to each of the heating units. The main controller is also used to control the operation of the heating unit corresponding to the driving component according to the on / off state signal, so as to heat the temperature limiter under test.

[0083] Each of the heating units includes: Heating elements are used to provide the heat required for testing; A temperature sensor is used to monitor the real-time temperature of the heating station; A temperature controller, electrically connected to the temperature sensor, is used to generate a second control signal based on a comparison between the real-time temperature and a preset temperature. The third relay is electrically connected to the temperature controller and the heating element, and is used to receive the second control signal to control the on / off state of the heating element.

[0084] The third relay is a solid-state relay.

[0085] See Figure 1The diagram shows the circuit schematic of a single heating unit. Each heating unit consists of a complete closed-loop temperature control system, specifically including the following four core components: The heating element, as the direct source of heat, provides the high-temperature environment required for testing the temperature limiter under test. In this embodiment, the heating element is preferably a ring-shaped heating ring 210. This structure surrounds the temperature limiter under test, achieving more uniform and efficient heat transfer.

[0086] The temperature sensor's function is to monitor the current temperature of the heating station in real time and accurately, and convert the temperature information into an electrical signal to feed back to the temperature controller. In this embodiment, to ensure temperature measurement accuracy and long-term stability, the temperature sensor is preferably an industrial-grade PT-100 resistance temperature detector (RTD), with one temperature sensor corresponding to each testing station.

[0087] The temperature controller's function is to execute high-precision temperature regulation logic. In this embodiment, the temperature controller is preferably an AI-SINK brand intelligent temperature controller (model AI-516). It receives real-time temperature signals from a temperature sensor and continuously compares them with the user-preset target temperature value. Based on the deviation between the two, the temperature controller intelligently calculates the required heating power through its built-in PID (proportional, integral, derivative) control algorithm and generates a corresponding second control signal.

[0088] The third relay, acting as an actuator switch connecting the temperature controller and the heating element, receives the low-voltage second control signal from the temperature controller and uses it to control the on / off state of the high-voltage AC power supply to the heating element. Since the PID algorithm generates high-frequency on / off commands to achieve precise power regulation, the third relay must possess extremely high switching speed and an ultra-long service life. In this embodiment, the third relay is preferably a solid-state relay (SSR, model SSR-40DA), whose absence of mechanical contacts perfectly meets this requirement.

[0089] The adoption of this distributed, closed-loop independent heating unit design is mainly based on the following considerations: To achieve versatility, by equipping each workstation with an independent temperature controller, operators can set a test temperature of 85°C for workstation 1 to test model A temperature limiter, and simultaneously set a test temperature of 105°C for workstation 2 to test model B temperature limiter. This flexibility is unmatched by centralized heating systems, greatly expanding the applicability of the tooling.

[0090] Achieving high precision hinges on the operating temperature of the temperature limiter, a critical performance indicator as any deviation from the ambient temperature directly impacts the validity of the test results. Employing a professional temperature controller with PID closed-loop control, compared to simple on / off control by a main controller (PLC), minimizes temperature fluctuations (e.g., ±0.5℃), ensuring both the stringency of the testing conditions and the reliability of the results.

[0091] To achieve high reliability and modularity, the complex temperature control tasks are separated from the main controller (PLC) and handled by individual independent temperature controllers. This design distributes the control tasks, simplifies the main controller's program logic, and allows it to focus more on core tasks such as sequential control, counting, and safety interlocking. Furthermore, each heating unit is a standardized module; a failure in any one unit will only affect that single workstation, preventing system-wide failure, and replacement and maintenance are extremely convenient.

[0092] The working process of the cooling unit in this embodiment is as follows: S1. Parameter settings: Set a target temperature for the workstation, such as 90℃, through the panel on the temperature controller or communication with the host computer.

[0093] S2, Closed-loop control start: When the main controller drives the temperature limiter under test into the heating station, the temperature controller starts to work.

[0094] S3, Real-time adjustment process: S31. The temperature controller reads the current temperature, for example, 30℃, from the PT-100 temperature sensor.

[0095] S32, the temperature controller compares it with the set value of 90℃ and finds a huge temperature difference of 60℃. Based on this, the PID algorithm calculates that 100% power output is required.

[0096] S33. The temperature controller sends a continuous on signal (second control signal) to the solid-state relay (SSR). The SSR remains on, the heating ring 210 operates at full power, and the temperature rises rapidly.

[0097] S34. When the temperature approaches 90℃ (for example, reaching 88℃), the PID algorithm will reduce the power output in advance, and the temperature controller will start sending pulse-type on / off signals to the SSR at a very high frequency. By adjusting the duty cycle of the pulse, the average power of the heating ring 210 is precisely controlled.

[0098] S35. The system reaches dynamic equilibrium around 90℃, and the temperature controller continuously makes fine adjustments to compensate for the heat lost to the environment and keep the temperature firmly locked at the set value.

[0099] In addition to the implementation methods mentioned above, this embodiment can also be implemented in the following ways: In addition to the heating ring 210, depending on the shape of the temperature limiter under test and the testing requirements, a flat plate heater, ceramic heating element, high-power infrared lamp, or hot air circulation system can also be used as the heat source.

[0100] The PT-100 resistance temperature detector (RTD) is the preferred choice for medium and low temperature ranges. For testing scenarios with higher temperatures, thermocouples with different calibrations, such as type K and type J, can be selected.

[0101] In some high-end applications, a high-performance PLC module with integrated multi-channel PID control can be selected to centralize the temperature control task in the main controller. However, this increases the cost and programming complexity of the PLC. For applications where high precision is not required, a simple on / off control using ordinary temperature relays or thermostats can be used, but this will sacrifice temperature stability.

[0102] Example 5 like Figures 1 to 5 As shown, this embodiment provides a general-purpose tooling for testing the on / off state of a thermostat counting device. Based on the general-purpose tooling framework constructed in Embodiment 1, this embodiment provides a preferred specific implementation scheme for the overall physical layout and driving method of the tooling. Furthermore, the heating station of this general-purpose tooling for testing the on / off state of a thermostat counting device also includes a heating chamber 200, the heating station being located inside the heating chamber 200, and the cooling station being located outside the heating chamber 200. The driving component is a cylinder 300. Each cylinder 300 is used to drive the corresponding temperature limiter under test to extend into the heating chamber 200, or to drive the corresponding temperature limiter under test to retract outside the heating chamber 200.

[0103] The tooling in this embodiment is structurally centered around one or more heating chambers 200 (accommodating a total of ten workstations). Each heating chamber 200 is a box with good thermal insulation properties, and its internal space is defined as the heating workstation. Conversely, the surrounding area outside the heating chamber 200 is defined as the cooling workstation. The walls of the heating chamber 200 physically separate the high-temperature heating zone and the ambient-temperature cooling zone.

[0104] To facilitate the transfer of the temperature limiter under test between the heating station inside the chamber and the cooling station outside the chamber, the driving component in this embodiment is specifically a cylinder 300. Each testing station is independently equipped with a cylinder 300. These cylinders 300 are fixedly mounted on the frame of the fixture, with the axis of motion of their piston rods perpendicular to the wall of the heating chamber 200. A through hole is provided on the wall of the heating chamber 200 corresponding to the position of each cylinder 300. A special clamp is installed at the end of the piston rod of the cylinder 300 to firmly hold the temperature limiter under test. In the initial or cooling state, the piston rod of the cylinder 300 is in the retracted position, and the temperature limiter under test is located in the cooling station outside the chamber; when the piston rod of the cylinder 300 extends, it passes through the through hole in the chamber wall, precisely delivering the temperature limiter under test into the heating station inside the heating chamber 200.

[0105] This layout of cooling and heating stations, combined with the 300-cylinder drive design, is primarily based on the following considerations: To maximize thermal efficiency and temperature control accuracy, the primary purpose of the heating chamber 200 is to create a stable, uniform, and energy-concentrated thermal field. The chamber structure effectively reduces heat loss to the surrounding environment and isolates it from external airflow and other environmental factors. This not only saves heating energy but, more importantly, provides an ideal working environment for the precision temperature control system described in Example 4, thus ensuring high stability and consistency of the test temperature—a prerequisite for accurate and reliable test results.

[0106] To achieve the fastest cooling speed, the cooling station is located outside the heating chamber 200 to completely physically isolate the heat source. When the cylinder 300 pulls the scorching hot temperature limiter out of the chamber, the limiter instantly enters the cooler external environment, creating a huge temperature difference and greatly improving heat dissipation efficiency. This design allows the forced air cooling described in Example 3 to achieve maximum effectiveness, thereby minimizing the cooling time and thus shortening the single cycle of the entire test.

[0107] Reasons for choosing cylinder 300 as the drive component: High speed and high reliability are required, and life testing demands that the actuator complete tens of thousands or even hundreds of thousands of reciprocating motions in a very short time. The 300 cylinder, powered by compressed air, features fast response and decisive action, meeting the need for rapid switching between workstations. At the same time, its simple and robust structure, extremely low failure rate, and ability to handle long-term, high-frequency repetitive work are all well-suited to this task.

[0108] Cost-effectiveness and ease of control: Pneumatic systems (cylinder 300, solenoid valves, air pipes, etc.) are technologically mature and inexpensive, making them a highly cost-effective choice for industrial automation. Their control logic is simple; the digital output port of the main controller (PLC) can directly drive the solenoid valve, thereby controlling the extension and retraction of cylinder 300. The control scheme is simple and reliable.

[0109] In this embodiment, the complete movement flow of a workstation is as follows: S1. Enter the heating station: When the main controller determines that a certain temperature limiter under test needs to be heated, it outputs an extension signal to the solenoid valve controlling the cylinder 300 at that position. The solenoid valve reverses, and compressed air enters the rodless chamber of cylinder 300, pushing the piston rod to extend. The piston rod drives the temperature limiter under test smoothly through the chamber wall, into the heating chamber 200, and stops at the preset heating position (this position is directly opposite the heating ring 210).

[0110] S2, Return to cooling station: Once the main controller detects that the temperature limiter under test has been successfully disconnected, it immediately sends a retraction signal to the solenoid valve. The solenoid valve then reverses direction, and compressed air enters the rod chamber of cylinder 300. The piston rod retracts rapidly, pulling the temperature limiter under test out of the heating chamber 200, exposing it completely to the cooling station outside the chamber. At the same time, the main controller activates the corresponding cooling unit to force-cool it.

[0111] In addition to the implementation methods mentioned above, this embodiment can also be implemented in the following ways: In addition to cylinder 300, electric actuators can also be used, such as ball screw actuators driven by servo motors or stepper motors. The advantage of electric actuators is that they allow for more precise programmable control of the speed, acceleration, and stopping position, but they are relatively more expensive and more complex to control.

[0112] The heating chamber 200 can be placed above or below the workstation, and the driving component (such as a cylinder 300 or an electric push rod) is vertically installed, moving the temperature limiter to be tested into or out of the heating chamber 200 by vertical movement. This layout helps to save the floor space of the equipment.

[0113] Multiple temperature limiters to be tested can also be mounted on the edge of a rotatable disc. The heating station (e.g., an arc-shaped heating hood) and the cooling station (e.g., an area with an air nozzle) are fixed at different angular positions on the disc. The main controller controls the stepping rotation of the disc, sequentially feeding each temperature limiter to be tested into the heating and cooling zones. The driving component in this case is the rotating indexing disc.

[0114] The heating chamber 200 is not limited to a closed chamber; it can also be in the form of a heating tunnel or a heating hood. The core purpose is to create a relatively independent and controllable heating area.

[0115] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of this application. Any specific values ​​in all examples shown and discussed herein should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0116] Furthermore, it should be noted that the use of terms such as "first" and "second" is merely for ease of distinction, and unless otherwise stated, these terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application.

[0117] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A universal tooling for testing the on / off state of a temperature limiter, characterized in that, include: Heating station and cooling station; Multiple driving components, each of which is used to mount the temperature limiter under test and to drive the temperature limiter under test to reciprocate between the heating station and the cooling station; The main controller is electrically connected to each of the driving components and each of the temperature limiters under test. It is used to receive the on / off status signal of each temperature limiter under test, and to perform independent on / off counting of the corresponding temperature limiter under test according to each on / off status signal, and to independently control the movement of the corresponding driving component.

2. The universal tooling for testing the on / off state of a temperature limiter according to claim 1, characterized in that, It also includes multiple signal conversion circuits; Each of the temperature limiters under test is electrically connected to the main controller through one of the signal conversion circuits; The signal conversion circuit is used to convert the on / off state of the temperature limiter under test into a first control signal that the main controller can receive.

3. The universal tooling for testing the on / off state of a temperature limiter according to claim 2, characterized in that, The signal conversion circuit includes: The first relay, the control terminal of the first relay is connected in series with the corresponding temperature limiter to be tested; The second relay has its control terminal electrically connected to the output of the first relay, and its output terminal electrically connected to the main controller. The second relay is used to output the first control signal to the main controller.

4. The universal tooling for testing the on / off state of a temperature limiter according to claim 3, characterized in that, The first relay is an AC contactor, and the second relay is an intermediate relay.

5. The universal tooling for testing the on / off state of a temperature limiter according to claim 1, characterized in that, The cooling station includes multiple cooling units, and each cooling unit corresponds to one of the driving components. The main controller is electrically connected to each of the cooling units. The main controller is also used to control the operation of the cooling unit corresponding to the driving component according to the on / off state signal, so as to cool the corresponding temperature limiter under test.

6. The universal tooling for testing the on / off state of a temperature limiter according to claim 5, characterized in that, Each of the cooling units includes: A cooling gas pipe (100) is used to connect to a cooling gas source, and the outlet of the cooling gas pipe (100) faces the temperature limiter to be moved to the cooling station. A solenoid valve is located inside the cooling gas pipeline (100) and electrically connected to the controller. It is used to control the connection and disconnection between the cooling gas pipeline (100) and the cooling gas source under the control of the main controller.

7. The universal tooling for testing the on / off state of a temperature limiter according to claim 1, characterized in that, The heating station includes multiple heating units, and each heating unit corresponds to one of the driving components. The main controller is electrically connected to each of the heating units. The main controller is also used to control the operation of the heating unit corresponding to the driving component according to the on / off state signal, so as to heat the corresponding temperature limiter under test.

8. The universal tooling for testing the on / off state of a temperature limiter according to claim 7, characterized in that, Each of the heating units includes: Heating elements are used to provide the heat required for testing; A temperature sensor is used to monitor the real-time temperature of the heating station; A temperature controller, electrically connected to the temperature sensor, is used to generate a second control signal based on a comparison between the real-time temperature and a preset temperature. The third relay is electrically connected to the temperature controller and the heating element, and is used to receive the second control signal to control the on / off state of the heating element.

9. The universal tooling for testing the on / off state of a temperature limiter according to claim 8, characterized in that, The third relay is a solid-state relay.

10. The universal tooling for testing the on / off state of a temperature limiter according to claim 1, characterized in that, It also includes a heating chamber (200), the heating station being located inside the heating chamber (200), and the cooling station being located outside the heating chamber (200); The driving component is a cylinder (300), and each cylinder (300) is used to drive the corresponding temperature limiter under test to extend into the heating box (200), or to drive the corresponding temperature limiter under test to retract outside the heating box (200).

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