Heat treatment control system for bearing steel ball production

Abstract

The utility model discloses a heat treatment control system for bearing steel ball production, and relates to the technical field of heat treatment. The bearing steel ball temperature control system solves the problems that in the existing bearing steel ball heat treatment process, the temperature control precision is insufficient, and the cooling rate stability is poor, and comprises a distributed node unit, a central control unit and a remote monitoring unit, the central control unit coordinates the work of each node and executes a control strategy, and the remote monitoring unit provides real-time monitoring, data analysis and fault early warning functions; according to the invention, the precision of temperature control and the stability of the cooling rate are greatly improved, and the consistency and the stability of the quenching process are ensured, so that the production quality and the performance of the bearing steel balls are remarkably improved, and the production requirements of high precision and high quality are met.

Description

Technical Field

[0001] This utility model relates to the field of heat treatment technology, and more specifically to a heat treatment control system for the production of bearing steel balls. Background Technology

[0002] With the development of modern industry, bearing steel balls, as important components in mechanical transmission, face increasingly higher performance and quality requirements. Heat treatment, a crucial step in bearing steel ball production, directly impacts product quality and production efficiency due to the technological level of its control system. Therefore, optimizing the heat treatment control system has become an important direction for improving the quality of bearing steel balls.

[0003] Most existing heat treatment control systems for bearing steel ball production employ single-point heating combined with PID control algorithms to automate the heat treatment process. However, with increasing production requirements, traditional control systems are gradually revealing their shortcomings in temperature control accuracy and cooling rate stability, making it difficult to meet the demands of high-precision, high-quality production. Firstly, regarding temperature control, existing systems suffer from insufficient accuracy due to limitations in sensor precision and PID algorithms, failing to accurately control the quenching temperature and consequently affecting the microstructure and properties of the bearing steel balls. Secondly, in terms of cooling rate control, insufficient system stability leads to large fluctuations in the cooling rate, making it difficult to ensure the consistency and stability of the quenching process, thus affecting the hardness and wear resistance of the bearing steel balls. Utility Model Content

[0004] The purpose of this invention is to design a heat treatment control system for the production of bearing steel balls to address the shortcomings mentioned in the background art.

[0005] To achieve the above-mentioned technical effects, the present invention adopts the following technical solution:

[0006] A heat treatment control system for the production of bearing steel balls includes: a distributed node unit, a central control unit, and a remote monitoring unit;

[0007] The distributed node unit is used to control temperature sensors, graphite resistance heaters and cooling pipes distributed in different locations of the heat treatment furnace, and to perform local temperature monitoring, heating and cooling control.

[0008] The central control unit is used to coordinate the work of all distributed nodes, execute control strategies, and perform remote monitoring and fault diagnosis.

[0009] The remote monitoring unit is used to provide real-time monitoring, data analysis and fault early warning functions;

[0010] The output and input terminals of the distributed node unit are electrically connected to the central control unit and the remote monitoring unit; the output and input terminals of the central control unit are electrically connected to the remote monitoring unit.

[0011] Furthermore, the distributed node unit includes a temperature sensor interface, a heating drive circuit, and a cooling control circuit; the output of the temperature sensor interface unit is connected to the input of the central control unit via an SPI interface; the input of the heating drive circuit receives the PWM signal from the central control unit, and its output is connected to the graphite resistance heater via a high-voltage cable; the input of the cooling control circuit receives the PWM signal from the central control unit, and its output is connected to the flow control valve drive circuit via a control cable.

[0012] Furthermore, the heating drive circuit includes a first optocoupler isolator, a high-frequency inverter, a power amplifier, a DC power supply, and a graphite resistance heater; the anode of the first optocoupler is connected to the central control unit to receive PWM signals, the cathode is grounded, the collector is connected to the inverter power supply Vcc, and the emitter is connected to the input terminal of the high-frequency inverter; the high-frequency inverter uses an IGBT module, the collector of the IGBT module is connected to the positive terminal of the DC power supply, the emitter is connected to the negative terminal of the DC power supply and one end of the graphite resistance heater, and the gate is connected to the output side of the first optocoupler isolator; the drain of the power amplifier is connected to the emitter of the IGBT module, the source is connected to the other end of the graphite resistance heater and grounded, and the gate is connected to the gate of the IGBT module.

[0013] Furthermore, the gates of the IGBT module and the power amplifier are connected via a 10Ω current-limiting resistor.

[0014] Furthermore, the cooling control circuit includes a second optocoupler isolator and a flow control valve drive circuit; the anode of the second optocoupler is connected to the central control unit, the cathode is grounded, the collector is connected to the power supply of the flow control valve drive circuit, and the emitter is connected to the control input of the flow control valve drive circuit; the flow control valve drive circuit uses a solenoid valve driver, the input terminal IN of the solenoid valve driver is connected to the output side of the second optocoupler isolator, the output terminal OUT of the solenoid valve driver is connected to the cooling water valve coil, and the power supply terminals Vcc and GND of the solenoid valve driver are connected to the positive and negative terminals of the system power supply, respectively.

[0015] Furthermore, the central control unit includes a processor, a PID control circuit, and a communication interface circuit; the processor uses an STM32F769 to perform multi-node temperature control and data calculation; the processor's input receives temperature data signals from each distributed node, and its output sends PWM signals to the heating drive circuit and cooling control circuit through the PID control circuit; the communication interface unit's input receives data signals from the distributed nodes, and its output is connected to the distributed nodes via a CAN bus and to a remote monitoring unit via a wireless communication network.

[0016] Furthermore, the TIM1_CH1 of the STM32F769 is connected to the input terminal of the first optocoupler isolator; the TIM2_CH1 of the STM32F769 is connected to the input terminal of the second optocoupler isolator.

[0017] Furthermore, the remote monitoring unit includes a data acquisition and processing subunit, a user interface subunit, and an alarm subunit; the input end of the data acquisition and processing subunit receives data signals from the central control unit, and the output end sends processed data to the user interface subunit and the alarm subunit; the input end of the user interface subunit receives the processed data from the data acquisition and processing subunit, and the output end sends user operation instructions to the central control unit; the input end of the alarm subunit receives abnormal data from the data acquisition and processing subunit, and the output end sends alarm information to the user interface and maintenance personnel.

[0018] In summary, due to the adoption of the above technical solution, the beneficial effects of this utility model are:

[0019] 1. By introducing distributed node units, precise control of temperature sensors at different locations within the heat treatment furnace can be achieved. Compared to traditional single-point heating combined with PID control algorithms, this distributed control strategy can more comprehensively monitor and adjust the furnace temperature, thereby significantly improving the accuracy of temperature control. It solves the problem of insufficient temperature control accuracy in existing systems due to limitations in sensor accuracy and PID algorithms, ensuring precise control of the quenching temperature and thus optimizing the microstructure and properties of the bearing steel balls.

[0020] 2. The distributed node units not only control the heating process but also manage the cooling pipelines, enabling the cooling process to be localized and precise. The central control unit coordinates the cooling operations of each distributed node, ensuring the consistency and stability of the cooling rate. This solves the problem of insufficient cooling rate stability in existing systems, reduces fluctuations in the cooling rate, and thus guarantees the consistency and stability of the quenching process, contributing to improved hardness and wear resistance of bearing steel balls.

[0021] 3. The central control unit, as the core of the system, is responsible for coordinating the work of all distributed nodes and executing control strategies. Meanwhile, the remote monitoring unit provides real-time monitoring, data analysis, and fault early warning functions, enhancing the overall performance and reliability of the system. Furthermore, real-time monitoring and data analysis allow for the timely detection and handling of potential faults, reducing production interruptions and improving production efficiency. The fault early warning function can notify maintenance personnel in advance, minimizing the impact of faults on production. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, wherein:

[0023] Figure 1 This is a diagram of the overall working architecture of this utility model;

[0024] Figure 2 This is a further detailed working structure diagram of the present invention;

[0025] Figure 3 This is a schematic diagram of the control principle of this utility model. Detailed Implementation

[0026] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0027] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0028] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediary element present. Conversely, when an element is said to be "directly" connected to another element, there is no intermediary element. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0029] like Figures 1-3 As shown, a heat treatment control system for the production of bearing steel balls includes: a distributed node unit, a central control unit, and a remote monitoring unit; the output and input terminals of the distributed node unit are electrically connected to the central control unit and the remote monitoring unit; the output and input terminals of the central control unit are electrically connected to the remote monitoring unit.

[0030] The distributed node unit is used to control temperature sensors, graphite resistance heaters, and cooling pipes distributed at different locations in the heat treatment furnace, performing localized temperature monitoring, heating, and cooling control. The distributed node unit includes a temperature sensor interface, a heating drive circuit, and a cooling control circuit. The output of the temperature sensor interface unit is connected to the input of the central control unit via an SPI interface. The input of the heating drive circuit receives a PWM signal from the central control unit, and its output is connected to the graphite resistance heater via a high-voltage cable. The input of the cooling control circuit receives a PWM signal from the central control unit, and its output is connected to the flow control valve drive circuit via a control cable.

[0031] In a specific embodiment, the temperature sensor interface unit employs a fiber optic temperature sensor (such as a DTS distributed temperature sensor), featuring high accuracy (±0.5℃) and a fast response time (less than 1 second). This sensor communicates with the central control unit via an SPI interface to ensure real-time data transmission. The heating drive circuit uses a high-frequency inverter (such as an IGBT module FZ1200R17KL4C) to convert DC power into a high-frequency AC signal to drive the graphite resistance heater. The heating drive circuit receives PWM signals from the central control unit and adjusts the heating power through the IGBT module to ensure rapid heating and stable control. The cooling control circuit includes a variable frequency fan drive circuit (such as a Mitsubishi FR-E740) and a solenoid valve driver (such as a VT100) for adjusting the cooling fan speed and water flow rate. The cooling control circuit also receives PWM signals from the central control unit and dynamically adjusts the operating status of the cooling equipment to ensure the consistency and stability of the cooling rate.

[0032] In the specific implementation process, the heat treatment furnace is divided into heating zone, quenching zone, and heat preservation zone. Each node in the heating zone is equipped with an independent heating device, namely a graphite resistance heater. A GRH-5kW graphite resistance heater with a power of 5kW is selected. The graphite resistance heater is fixed to the outside of the furnace wall with high-temperature resistant bolts and isolated from the furnace interior space by a heat insulation layer to prevent heat loss to the outside. The output terminal of the heating drive circuit is equipped with a 1000V withstand voltage and a 4mm² cross-sectional area. 2 The high-voltage cable is connected to the graphite resistance heater. A WZP-230 platinum resistance temperature sensor is used, with a measurement range of 0-1000℃ and an accuracy of ±0.5℃. It is tightly mounted on the inner side of the furnace wall, close to the graphite resistance heater, using a specially designed ceramic mounting bracket to ensure accurate temperature measurement in that area. The temperature sensor interface is connected to the sensor via a three-wire connection to eliminate the influence of wire resistance on measurement accuracy. The temperature data is then transmitted to the central control unit via an SPI interface at a rate of 10Mbps.

[0033] In the quenching zone, the output of the cooling control circuit is connected to the flow control valve drive circuit via a control cable, thereby controlling the electromagnetic flow valve. A DN25 diameter valve with a flow rate adjustment range of 0-10m³ is selected. 3 An electromagnetic flow valve with a flow rate of [number] h is installed on the quenching fluid pipeline via a flange, ensuring a good seal. At the inlet node, a thermocouple temperature sensor (model WRN-231, measuring range 0-800℃, accuracy ±0.8℃) is installed to monitor the quenching fluid inlet temperature in real time. Another thermocouple of the same model is installed at the outlet node to monitor the residual temperature of the steel balls after quenching. The temperature sensor interface converts and processes the sensor signal before transmitting it to the central control unit via an SPI interface. Based on the temperature data, the central control unit controls the cooling control circuit via a PWM signal to adjust the opening of the electromagnetic flow valve, achieving precise control of the quenching cooling rate.

[0034] Each node in the insulation zone is equipped with a 3kW ceramic heating element, which is attached to the inner side of the furnace wall using high-temperature resistant adhesive. A fiber optic temperature sensor (model FOT-600, measurement range -50-600℃, accuracy ±0.3℃) is used, utilizing its anti-electromagnetic interference properties and fixed to the furnace wall near the ceramic heating element using a special clamp. The temperature sensor interface converts the optical signal from the fiber optic sensor into an electrical signal, which is then processed and transmitted to the central control unit via an SPI interface. Based on the temperature feedback, the central control unit adjusts the power of the ceramic heating element using the PWM signal of the heating drive circuit to maintain a stable temperature in the insulation zone. This distributed node layout and installation method allows each node to independently detect temperature and control heating or cooling, more accurately meeting the process requirements of different areas of the heat treatment furnace and ensuring the stability and consistency of the bearing steel ball heat treatment quality.

[0035] In practical applications, the distributed node unit operates as follows: First, fiber optic temperature sensors distributed at different locations within the heat treatment furnace collect temperature data in real time and transmit it to their respective distributed node units via the SPI interface. Each node unit, based on the received temperature data, calculates the required PWM signal using its built-in adaptive PID controller, controlling the heating power of the graphite resistance heater and the cooling rate of the cooling pipes. The heating drive circuit receives the PWM signal from the central control unit and adjusts the operating state of the heating element through the IGBT module. Specifically, the PWM signal is transmitted to the gate of the IGBT module via an optocoupler (HCPL-2630), and the IGBT gate is protected by a current-limiting resistor (e.g., 10Ω). The IGBT module converts the DC power supply into a high-frequency AC signal to drive the graphite resistance heater, ensuring rapid heating and stable control. The cooling control circuit adjusts the speed of the variable frequency fan and the opening of the solenoid valve according to the PWM signal, ensuring precise control of the cooling medium. The variable frequency fan adjusts its speed according to the PWM signal, and the solenoid valve driver adjusts the cooling water flow rate according to the PWM signal, avoiding the problem of large cooling rate fluctuations in traditional cooling systems. All distributed nodes communicate with the central control unit via CAN bus or Ethernet, uploading temperature data and receiving control commands to ensure global coordination.

[0036] Compared with existing technologies, the distributed node unit of this invention exhibits significant advantages and features in the heat treatment control system for bearing steel ball production. First, multi-point distributed temperature monitoring ensures the uniformity and accuracy of temperature distribution throughout the heat treatment furnace, overcoming the limitations of traditional single-point control systems. Second, the intelligent PID controller based on fuzzy logic and adaptive algorithms achieves faster response and higher control accuracy, making it particularly suitable for the control requirements of nonlinear and time-varying systems. Furthermore, independent cooling node control ensures a stable and consistent cooling rate for each local area, avoiding the cooling rate fluctuation problem of traditional systems, thereby improving the hardness and wear resistance of the steel balls. Modular design enhances the system's reliability and flexibility, reducing the impact of single-point failures. Remote monitoring and diagnostic functions further optimize production management and maintenance processes; maintenance personnel can view the system status and perform operations at any time through a web interface or mobile application, promptly repairing faults and avoiding production interruptions.

[0037] Furthermore, the heating drive circuit includes a first optocoupler isolator, a high-frequency inverter, a power amplifier, a DC power supply, and a graphite resistance heater. The anode of the first optocoupler is connected to the central control unit to receive a PWM signal, the cathode is grounded, the collector is connected to the inverter power supply Vcc, and the emitter is connected to the input terminal of the high-frequency inverter. The high-frequency inverter uses an IGBT module. The collector of the IGBT module is connected to the positive terminal of the DC power supply, the emitter is connected to the negative terminal of the DC power supply and one end of the graphite resistance heater, and the gate is connected to the output side of the first optocoupler isolator. The drain of the power amplifier is connected to the emitter of the IGBT module, the source is connected to the other end of the graphite resistance heater and grounded, and the gate is connected to the gate of the IGBT module. The IGBT module and the gate of the power amplifier are connected through a 10Ω current-limiting resistor.

[0038] In practice, the PWM signal from the central control unit is first transmitted to the first optocoupler isolator, specifically the PC817 model. Its function is to electrically isolate the central control unit from the downstream high-voltage circuitry, preventing interference feedback and ensuring the purity and stability of the PWM signal. When the PWM signal passes through the optocoupler isolator, it is transmitted via light. The anode receives the PWM signal, the cathode is grounded, the collector is connected to the inverter power supply Vcc, and the emitter transmits the isolated signal to the high-frequency inverter.

[0039] The high-frequency inverter uses an FGH40N60SMD IGBT module. The IGBT module plays a crucial role here due to its high voltage, high current handling capability, and fast switching characteristics. The collector is connected to the positive terminal of the DC power supply, the emitter is connected to the negative terminal of the DC power supply and one end of the graphite resistance heater, and the gate receives the signal from the output side of the first optocoupler. When the PWM signal raises the gate potential of the IGBT module to a certain level through the optocoupler, the IGBT turns on, and the DC power supply powers the graphite resistance heater. Since the heating power required during the heat treatment process is large, it is difficult to meet the demand using only the IGBT module; therefore, a power amplifier is introduced.

[0040] The power amplifier selected is the IRF540N model. Its drain is connected to the emitter of the IGBT module, its source is connected to the other end of the graphite resistance heater and grounded, and its gate is connected to the gate of the IGBT module. Both gates are connected via a 10Ω current-limiting resistor. This resistor prevents excessive current from impacting the gate, protecting the IGBT module and the power amplifier. The power amplifier further amplifies the current, ensuring sufficient power for the graphite resistance heater to achieve efficient heating. By adjusting the duty cycle of the PWM signal, the conduction time of the IGBT module and the power amplifier can be changed, thereby precisely controlling the heating power of the graphite resistance heater to meet the temperature requirements of different heat treatment stages of the bearing steel balls.

[0041] In actual installation, the PC817 optocoupler isolator uses a standard DIP-4 package for easy soldering on the circuit board. Its pins connect to the central control unit and the high-frequency inverter using a 0.1mm² cross-sectional area connector. 2 The single-strand tinned copper wire ensures stable signal transmission. The FGH40N60SMD IGBT module must be mounted on a metal substrate with a heatsink to ensure effective heat dissipation during operation. The IGBT module is connected to the DC power supply using a 2.5mm² cross-sectional area wire. 2 The copper busbars ensure that they can carry large currents.

[0042] The IRF540N power amplifier is also installed in a well-ventilated area, and its connection to the IGBT module and graphite resistance heater uses a 1mm² cross-sectional area connector. 2 The conductors are as follows: A 10Ω current-limiting resistor with 1% accuracy is selected to ensure the accuracy of the current-limiting effect. The graphite resistance heater is a GRH-5kW model with a power of 5kW, fixed to the outside of the furnace wall with high-temperature resistant bolts, and connected to the heating drive circuit via a 1000V withstand voltage and a 4mm² cross-sectional area. 2 The high-voltage cable is connected. The DC power supply uses a switching power supply with an output voltage of 380V to provide stable DC power to the entire heating drive circuit.

[0043] During the operation of the heat treatment system, the heating drive circuits of each node work in concert. The central control unit generates a PWM signal with a corresponding duty cycle based on the preset heat treatment process and real-time temperature data fed back from the temperature sensor. This signal is transmitted to the PC817 optocoupler isolator, and after electrical isolation, it triggers the FGH40N60SMD IGBT module. When the PWM signal is high, the gate of the IGBT module receives sufficient voltage, the IGBT turns on, and the electrical energy from the DC power supply is transferred to the graphite resistance heater through the IGBT module, causing it to start heating.

[0044] Simultaneously, the IRF540N power amplifier operates due to the gate signal while the IGBT module is turned on, further amplifying the current and enhancing the heating effect on the graphite resistance heater. If the current temperature is lower than the set value, the central control unit increases the PWM signal duty cycle, extending the conduction time of the IGBT module and power amplifier, allowing the graphite resistance heater to receive more power and its temperature to rise; conversely, if the temperature is higher than the set value, the PWM signal duty cycle decreases, reducing the heating power. Throughout the process, the 10Ω current-limiting resistor consistently restricts the current flowing into the gate, protecting the IGBT module and power amplifier, ensuring the heating drive circuit operates stably and reliably, and precisely controlling the heating process.

[0045] In implementation, optocouplers achieve strong and weak current isolation, effectively avoiding interference between circuits, improving system stability and reliability, reducing the risk of control errors caused by interference, and making temperature control more precise. Secondly, the selected IGBT module and power amplifier combination can efficiently handle high current and high power, meeting the stringent heating power requirements during the heat treatment of bearing steel balls, ensuring that the graphite resistance heater can quickly and stably provide the required heat, thus improving heating efficiency. Furthermore, adjusting the heating power via PWM signals achieves precise temperature control, helping to improve the heat treatment quality of bearing steel balls, reducing product quality problems caused by temperature fluctuations, and increasing the product qualification rate. In addition, the reasonable selection and connection of various components ensures the reliability and durability of the entire heating drive circuit, reduces maintenance costs, and improves the overall operating efficiency of the system.

[0046] Furthermore, the cooling control circuit includes a second optocoupler isolator and a flow control valve drive circuit; the anode of the second optocoupler is connected to the central control unit, the cathode is grounded, the collector is connected to the power supply of the flow control valve drive circuit, and the emitter is connected to the control input of the flow control valve drive circuit; the flow control valve drive circuit uses a solenoid valve driver, the input terminal IN of the solenoid valve driver is connected to the output side of the second optocoupler isolator, the output terminal OUT of the solenoid valve driver is connected to the cooling water valve coil, and the power supply terminals Vcc and GND of the solenoid valve driver are connected to the positive and negative terminals of the system power supply, respectively.

[0047] In a specific embodiment, the central control unit generates corresponding control signals based on a preset cooling rate and real-time temperature data fed back from temperature sensors at each node. This signal is first transmitted to a second optocoupler, specifically a TLP521-1 model, whose anode is connected to the central control unit and whose cathode is grounded. When the signal from the central control unit raises the anode potential, the LED inside the optocoupler emits light, thus connecting the collector and emitter. The collector is connected to the power supply of the flow control valve drive circuit, and the emitter is connected to the control input of the flow control valve drive circuit. This safely transmits the weak electrical signal from the central control unit to the subsequent high-voltage control circuit, achieving electrical isolation, effectively preventing interference feedback, and ensuring the stability and accuracy of the control signal.

[0048] The flow control valve drive circuit uses a ULN2003A solenoid valve driver, whose input terminal IN receives a signal from the output side of the second optocoupler isolator. When the signal turns on the Darlington transistor inside the ULN2003A, current flows from the power supply terminal Vcc through the output terminal OUT of the solenoid valve driver to the cooling water valve coil. The ULN2003A has a high current amplification factor, providing sufficient drive current to control the electromagnetic attraction of the cooling water valve coil, thereby controlling the opening degree of the cooling water valve and achieving precise regulation of the cooling water flow rate to meet the cooling rate requirements of the bearing steel balls at different stages of the quenching process.

[0049] When installing the cooling control circuit, the TLP521-1 optocoupler isolator uses a DIP-4 package for easy soldering on the circuit board. Its pins connect to the central control unit and the flow control valve drive circuit using a 0.1mm² cross-sectional area connector. 2 The single-strand tinned copper wire ensures stable signal transmission. The ULN2003A solenoid valve driver also uses a DIP-16 package and is installed in a well-ventilated area to prevent heat generated during prolonged operation from affecting its performance. It uses a 0.5mm² cross-sectional area wire for connections with optocouplers, cooling water valve coils, and system power supplies. 2 The wiring ensures reliable current transmission. The cooling water valve is a normally closed 2-position 3-way solenoid valve, model ZCF-20B, with a rated voltage of 24V and a nominal diameter of 20mm, capable of meeting the system's cooling water flow regulation requirements. The solenoid valve coil is connected to the output terminal OUT of the ULN2003A, and the valve body is connected to the cooling water pipeline via a flange to ensure a good seal and prevent cooling water leakage. The system power supply is a 24V DC power supply, with its positive and negative terminals connected to the power terminals Vcc and GND of the ULN2003A respectively, providing stable power to the entire flow control valve drive circuit.

[0050] During the operation of the heat treatment system, the cooling control circuit continuously monitors and responds to temperature changes during the quenching process. When the bearing steel ball enters the quenching stage, the temperature sensor monitors the temperature of the steel ball and the quenching area in real time and feeds the data back to the central control unit. The central control unit generates a corresponding control signal based on the preset cooling curve and the current temperature. If the current temperature is higher than the preset cooling temperature, the central control unit outputs a high-level signal to the anode of the TLP521-1 optocoupler isolator, the optocoupler conducts, and the signal is transmitted to the input terminal IN of the ULN2003A solenoid valve driver. The internal circuit of the ULN2003A activates, ensuring sufficient current flows to the cooling water valve coil at the output terminal OUT, generating electromagnetic attraction, overcoming the spring force, opening the normally closed cooling water valve, and allowing cooling water to flow. As the temperature decreases, the central control unit gradually adjusts the duty cycle of the output signal based on the temperature feedback, causing the current output by the ULN2003A to change accordingly, thereby precisely controlling the opening degree of the cooling water valve, regulating the cooling water flow rate, and achieving precise control of the cooling rate. When the temperature reaches the preset value, the central control unit outputs a low-level signal, the optocoupler is cut off, the ULN2003A has no output, the cooling water valve closes, and cooling stops.

[0051] In practical implementation, this cooling control circuit, within the bearing steel ball heat treatment control system, effectively isolates strong and weak currents through an optocoupler isolator, significantly improving the system's anti-interference capability. This ensures accurate transmission of control signals, avoids cooling control errors caused by interference, and thus improves the stability of the product's quenching quality. Secondly, by using a ULN2003A solenoid valve actuator in conjunction with a suitable cooling water valve, the cooling water flow rate can be precisely adjusted, achieving accurate control of the cooling rate. This meets the quenching process requirements of bearing steel balls of different specifications, effectively improving the product's hardness, wear resistance, and other performance indicators, while reducing the scrap rate. Furthermore, the entire cooling control circuit has a reasonable structural design, uses highly reliable components, is easy to install, maintain, and replace, reducing system maintenance costs, improving equipment operating efficiency, and enhancing the stability and reliability of the entire heat treatment system, providing a strong guarantee for the high-quality production of bearing steel balls.

[0052] The central control unit coordinates the operation of all distributed nodes, executes control strategies, and performs remote monitoring and fault diagnosis. The central control unit includes a processor, a PID control circuit, and a communication interface circuit. The processor uses an STM32F769 to perform temperature control and data calculation for multiple nodes. The processor's input receives temperature data signals from each distributed node, and its output sends PWM signals to the heating drive circuit and cooling control circuit through the PID control circuit. The communication interface unit's input receives data signals from the distributed nodes, and its output connects to the distributed nodes via a CAN bus and to the remote monitoring unit via a wireless communication network. The STM32F769's TIM1_CH1 is connected to the input of the first optocoupler; the STM32F769's TIM2_CH1 is connected to the input of the second optocoupler.

[0053] In a specific embodiment, temperature sensors at each distributed node collect temperature data in real time and convert it into electrical signals, which are then transmitted to the central control unit. After receiving these temperature data signals, the input of the STM32F769 processor analyzes and calculates them using internal algorithms based on preset heat treatment process requirements and control strategies. For example, the real-time temperature is compared with the target temperature to obtain a temperature deviation value. Based on this deviation value, the PID control circuit generates corresponding control signals according to proportional (P), integral (I), and derivative (D) arithmetic rules. This control signal, after processing, is sent as a PWM signal to the heating drive circuit and cooling control circuit via the output of the STM32F769 processor. Specifically, the STM32F769's TIM1_CH1 is connected to the input of the first optocoupler, controlling the heating drive circuit and adjusting the duty cycle of the PWM signal to change the heating power of the graphite resistance heater; the STM32F769's TIM2_CH1 is connected to the input of the second optocoupler, controlling the cooling control circuit and adjusting the opening of the cooling water valve to control the cooling rate.

[0054] Meanwhile, the communication interface circuit acts as a data transmission bridge in the system. Its input receives various data signals from distributed nodes, including temperature data and equipment status. Its output enables high-speed and reliable data exchange with the distributed nodes via the CAN bus, ensuring real-time control and monitoring of each node. Simultaneously, it connects to a remote monitoring unit via a wireless communication network (such as a 4G or Wi-Fi module) to achieve remote monitoring and management functions.

[0055] The central control unit, an STM32F769 processor core board, uses a standard pin interface and is fixed to a custom circuit board via soldering or plug-in. This circuit board is equipped with corresponding power management circuitry to provide stable 3.3V and 1.2V operating voltages for the STM32F769. The CAN bus interface circuit uses an MCP2515 controller and a TJA1050 transceiver. The MCP2515 connects to the STM32F769 via an SPI interface, while the TJA1050 converts the CAN bus signals into level signals suitable for processing by the MCP2515. The CAN bus uses shielded twisted-pair cable with a characteristic impedance of 120Ω to ensure interference immunity during data transmission. For wireless communication network connection, a SIM7600CE 4G module (if 4G communication is used) is selected and connects to the STM32F769 via a serial port to achieve data interaction with the remote monitoring unit. The module's power pins are connected to the 5V output of the system power supply, and a power conversion chip provides a suitable operating voltage. The entire control cabinet has neat wiring, with strong and weak currents separated to avoid electromagnetic interference. The modules are connected by ribbon cables or DuPont wires to ensure a secure and reliable connection.

[0056] During the operation of the heat treatment system, the central control unit works continuously. Distributed nodes continuously transmit temperature data to the central control unit, which receives and processes this data in real time. For example, during the heating phase, if the temperature of a node is lower than the target value, the processor calculates the temperature deviation. The PID control circuit generates a corresponding PWM signal based on this deviation and sends it to the first optocoupler via TIM1_CH1. This, in turn, adjusts the heating drive circuit, increasing the power of the graphite resistance heater and raising the temperature of that node. During the cooling phase, if the temperature is higher than the preset value, the processor similarly calculates the deviation and sends a PWM signal to the second optocoupler via TIM2_CH1. This controls the cooling control circuit, increasing the opening of the cooling water valve and accelerating the cooling rate. Simultaneously, the communication interface circuit feeds back data from each node and system status information to the distributed nodes in real time via the CAN bus, enabling local real-time monitoring and control. Furthermore, data is transmitted to a remote monitoring unit via a wireless communication network, allowing operators to view the system's operating status and adjust process parameters in real time. If a system fault occurs, the central control unit can quickly diagnose the faulty node and its cause and promptly notify the operators via the communication network for timely repair measures.

[0057] In implementation, the powerful computing and control capabilities of the central control unit ensured precise temperature control across multiple nodes, effectively improving the heat treatment quality of bearing steel balls, reducing product defects caused by improper temperature control, and increasing the product qualification rate. Secondly, the combination of CAN bus and wireless communication network enabled local and remote monitoring and management of the system, allowing operators to access system information and adjust parameters anytime, anywhere, improving production flexibility and convenience. Furthermore, the fault diagnosis function can quickly locate system faults, reducing equipment downtime, lowering maintenance costs, and improving system reliability and stability. Overall, the central control unit significantly enhances the automation level and production efficiency of the entire heat treatment control system, providing a strong guarantee for the high-quality, large-scale production of bearing steel balls.

[0058] The remote monitoring unit provides real-time monitoring, data analysis, and fault early warning functions. It includes a data acquisition and processing subunit, a user interface subunit, and an alarm subunit. The data acquisition and processing subunit receives data signals from the central control unit at its input and sends processed data to the user interface subunit and the alarm subunit at its output. The user interface subunit receives processed data from the data acquisition and processing subunit at its input and sends user operation commands to the central control unit at its output. The alarm subunit receives abnormal data from the data acquisition and processing subunit at its input and sends alarm information to the user interface and maintenance personnel at its output.

[0059] In a specific embodiment, the data acquisition and processing subunit, acting as the front line of information collection, establishes a communication connection with the central control unit to receive a large amount of data signals, such as temperature and equipment operating status, from various distributed nodes. For example, a high-performance data acquisition module (such as Advantech ADAM-4017+) is used, which can acquire analog data at high speed and high precision and convert it into digital signals for preliminary processing. This data may include real-time temperatures of different nodes, operating parameters of heating and cooling equipment, etc. The data acquisition and processing subunit uses specific algorithms to perform in-depth analysis of the acquired data, such as using statistical methods to determine whether the data fluctuation range is within the normal range, or using machine learning algorithms to predict equipment operating trends. The processed data is then sent to the user interface subunit and the alarm subunit respectively.

[0060] The user interface subunit is designed to provide operators with an intuitive and convenient interactive platform. It receives processed data and uses graphical interface development tools (such as the Qt framework) to present the data in visual formats such as charts and curves, facilitating real-time monitoring of the system's operating status. Simultaneously, operators can input operating commands through the user interface, which are then sent to the central control unit for remote control of the heat treatment process.

[0061] The alarm subunit focuses on monitoring and reporting system anomalies. When the data acquisition and processing subunit detects abnormal data, such as a node temperature exceeding a set threshold, the alarm subunit immediately receives this abnormal information. It has a built-in alarm logic judgment program that, based on the anomaly type and preset alarm rules, sends alarm information to maintenance personnel via SMS (e.g., SIM800C) and simultaneously displays an alarm notification on the user interface, ensuring relevant personnel are promptly informed and can address the issue.

[0062] During system operation, the data acquisition and processing subunit continuously acquires data from the central control unit, collecting temperature data and equipment operating status data from each node every second. The acquired data is immediately processed to analyze whether it conforms to the preset normal range. For example, for a certain heating node, if the temperature fluctuates by more than ±5℃ within a short period, it is considered abnormal.

[0063] The processed data is transmitted to the user interface subunit in real time. On the industrial tablet PC's monitoring software interface, the temperature change trends of each node are displayed as dynamic curves, and the equipment operating parameters are presented in tabular form. Operators can view this information in real time. If a problem is detected, commands can be entered through the interface, such as adjusting the heating power or cooling rate of a node. These commands are sent to the central control unit via the network for execution. Simultaneously, the alarm subunit constantly monitors for abnormal data. Once abnormal data is received from the data acquisition and processing subunit, the alarm mechanism is immediately triggered. First, the audible and visual alarm sounds, attracting the attention of personnel in the monitoring room. Simultaneously, the SIM800C SMS module sends an SMS message containing details of the abnormality to the pre-set maintenance personnel's mobile phone number, such as "The temperature of a certain node in the heating zone has exceeded the upper limit; please handle it immediately," ensuring that the problem is resolved promptly and guaranteeing the stable operation of the heat treatment system.

[0064] The remote monitoring unit brings significant positive effects to the heat treatment control system for bearing steel ball production. Firstly, it enables real-time monitoring, allowing operators to fully grasp the system's operating status without being physically present on-site, improving the convenience and timeliness of monitoring and helping to promptly identify potential problems and prevent production accidents. Secondly, the data analysis function, by uncovering patterns in the data, provides a basis for optimizing the heat treatment process, thereby improving product quality and reducing production costs. Thirdly, the fault early warning function greatly shortens fault response time, reduces the impact of equipment failures on production, and improves equipment reliability and production efficiency. Overall, the remote monitoring unit enhances the intelligence level of the entire heat treatment control system and strengthens the company's competitiveness.

[0065] The following specific embodiments illustrate the heat treatment control system for bearing steel ball production:

[0066] In a box-type heat treatment furnace, heat transfer mainly occurs through three mechanisms: thermal radiation, thermal conduction, and thermal convection. In the heating zone, heat diffuses outwards from the central area, while the corners, due to their larger contact area with the external environment, experience faster heat dissipation through radiation. Heat loss increases after conduction to the furnace wall, easily leading to low-temperature zones. This system employs a high-precision platinum resistance temperature sensor, utilizing the characteristic of platinum metal resistance changing with temperature (exhibiting a relatively stable linear relationship within the 0-1000℃ range) to accurately sense the temperature. Its special ceramic encapsulation is not only high-temperature resistant and oxidation-resistant but also allows for a tight fit against the furnace wall, minimizing thermal resistance and accurately feeding back the true temperature at the corners, ensuring the system monitors the dynamics of heat transfer. For example, when the furnace temperature rises, the sensor's resistance value changes in real time, and this change is converted into a digital signal by the ADC on the control circuit board for subsequent processing.

[0067] In the quenching zone, the quenching fluid flows in and undergoes intense heat exchange with the steel balls, involving a complex convective heat transfer process. Thermocouple temperature sensors, utilizing the principle of thermoelectric potential generated by different metals under temperature changes (measurement range 0-800℃, accuracy ±0.8℃), rapidly capture sudden temperature changes during quenching. Their stainless steel protective sleeve effectively resists corrosion from the quenching fluid, ensuring stable sensing performance and allowing the system to monitor the quenching initiation temperature in real time, laying the foundation for precise control of the cooling rate.

[0068] The fiber optic temperature sensor in the insulation zone is based on the propagation characteristics of light. It measures the temperature by utilizing the changes in parameters such as light intensity and wavelength when light passes through the optical fiber under different temperature conditions (-50 to 600℃, accuracy ±0.3℃). The optical signal transmission is resistant to electromagnetic interference and is suitable for the complex electromagnetic environment of the insulation zone, providing accurate temperature data for stable insulation.

[0069] The graphite resistance heaters at the corners of the heating zone follow Joule's law; when current passes through high-purity graphite material (with moderate resistivity), electrical energy is efficiently converted into heat energy. The 5kW power is set based on simulation calculations of heat loss at the corners, allowing for rapid heat compensation as needed. The microcontroller (such as an STM32 series) on the control circuit board collects temperature data at 1-second intervals. Using a preset PID algorithm (Kp = 0.8 for fast response deviation, Ki = 0.05 to eliminate steady-state error, Kd = 0.02 to predict temperature trends), it precisely regulates the heater power via PWM signals to ensure coordinated temperature control between the corners and the center.

[0070] The electromagnetic flow valves at the inlet and outlet of the quenching zone, based on electromagnetic principles, control the valve core displacement by changing the current in the electromagnetic coil, thereby precisely regulating the quenching fluid flow rate (DN25, 0-10m). 3 / h adjustment range). A pressure sensor (range 0.1MPa, accuracy ±0.01MPa) monitors pipeline pressure in real time to ensure stable flow. A microcontroller (such as Arduino Mega) collects temperature and pressure signals, and communicates with the central control unit in real time via Ethernet according to the steel ball parameters (size, quantity) and central commands to finely control the cooling process.

[0071] In practice, temperature sensors constantly monitor the corners of the heating zone. Once the microcontroller detects that the measured temperature deviates from the target value (set based on the process curve, slightly higher than the center by 10-15℃) by more than ±2℃, it immediately drives the control circuit board to adjust the heater. If the corner temperature lags behind during the heating phase, the PWM duty cycle is increased to boost power; if the temperature exceeds the limit during the heat preservation phase, the power is reduced.

[0072] The inlet and outlet temperatures of the quenching fluid are monitored by thermocouples at the quenching zone inlet and outlet. At the inlet, if the temperature deviates from the target of 2030℃, the central control unit is notified to activate the cooling cycle to stabilize the temperature. At the outlet, the residual temperature of the steel balls is monitored; if it exceeds 100℃, the central control unit is prompted to increase the quenching fluid flow rate. The electromagnetic flow valve dynamically adjusts according to the diameter and batch of steel balls; for example, for 10mm diameter steel balls, the initial flow rate is 5m. 3 The flow rate is adjusted by 0.1 m³ / h as the quenching process progresses. 3 / h step size optimization.

[0073] In the middle and transition zone of the insulation area, fiber optic temperature sensors collect data periodically (every 5 seconds). A microcontroller (such as the MSP430 series) compares the temperature with the set temperature (550-600℃ in the middle, with fluctuations of ±3℃, and slightly lower and gentler gradient in the transition zone). If the deviation exceeds the standard, a PID algorithm (with parameters such as Kp=0.6) is used to adjust the power of the ceramic heating element. At the same time, data is exchanged with the central control via wireless communication such as ZigBee to maintain the insulation effect.

[0074] The central control unit receives data from each node and compares process parameters in real time. It immediately issues warnings and commands upon encountering node anomalies (temperature runaway, flow abnormalities). Furthermore, based on long-term accumulated data, it uses machine learning to optimize node PID coefficients and other parameters to adapt to diverse operating conditions and ensure high-precision, high-quality production.

[0075] Under stable operation, the temperature at the corners of the heating zone approaches that of the center, ensuring uniform heating of the steel balls. The graphite resistance heater operates smoothly according to temperature control with minimal power fluctuations. In the quenching zone, the inlet and outlet temperatures are precisely monitored, the quenching fluid flow rate and velocity are stable, the steel balls enter and exit the quenching environment in an orderly manner, the cooling rate is constant, the pressure sensor readings are stable, and the electromagnetic flow valve operates precisely. The central part of the holding zone maintains a constant temperature, the transition zone experiences a gradual temperature drop, the ceramic heating elements supply power as needed, all sensors provide stable feedback, and distributed nodes communicate smoothly with the central control unit. During dynamic adjustments, such as steel ball batch switching or process changes, the system responds swiftly. The heating zone quickly resets the target corner temperature and adjusts the heaters; the quenching zone optimizes cooling parameters based on the characteristics of the new steel balls; and the holding zone fine-tunes the temperature to adapt to new requirements. The central control unit efficiently coordinates all nodes to achieve a new balance in a short time, ensuring continuous production and stable product quality.

[0076] Compared to existing technologies, this system features distributed temperature measurement, with multiple types of high-precision sensors providing comprehensive coverage of critical areas. For example, precise monitoring of the heating zone's corners compensates for uneven heat loss, ensuring uniform heating of the steel balls throughout the process. This lays a solid foundation for the formation of ideal microstructures, significantly improving product quality stability and reducing scrap rates. The central control unit adjusts parameters in real time based on operating conditions, overcoming the poor adaptability of traditional fixed parameters. It can precisely control temperature at each stage, from heating and holding to quenching and cooling, meeting the high-precision heat treatment requirements of modern bearing steel balls. Furthermore, the system features precise monitoring of the quenching zone's inlet and outlet, real-time adjustment of the electromagnetic flow valve, and precise liquid supply based on the steel ball's real-time condition. Pressure monitoring ensures a stable flow rate, guaranteeing consistent cooling rates, uniform internal stress in the steel balls, and stable improvements in hardness and wear resistance. The system can flexibly customize cooling strategies based on different steel ball sizes, materials, and batches, providing precise control from initial flow setting to dynamic adjustments. Existing technologies often use a one-size-fits-all approach, failing to meet diverse production needs. This system empowers personalized, high-quality production.

[0077] While specific embodiments of this utility model have been described above, those skilled in the art should understand that these specific embodiments are merely illustrative. Those skilled in the art can omit, substitute, and modify the details of the above methods and systems in various ways without departing from the principles and essence of this utility model. For example, combining the above method steps to perform substantially the same function and achieve substantially the same result according to substantially the same method falls within the scope of this utility model. Therefore, the scope of this utility model is defined only by the appended claims.

Claims

1. A heat treatment control system for the production of bearing steel balls, characterized in that: include: Distributed node units, central control unit, and remote monitoring unit; The distributed node unit is used to control temperature sensors, graphite resistance heaters and cooling pipes distributed in different locations of the heat treatment furnace, and to perform local temperature monitoring, heating and cooling control. The central control unit is used to coordinate the work of all distributed nodes, execute control strategies, and perform remote monitoring and fault diagnosis. The remote monitoring unit is used to provide real-time monitoring, data analysis and fault early warning functions; The output and input terminals of the distributed node unit are electrically connected to the central control unit and the remote monitoring unit; the output and input terminals of the central control unit are electrically connected to the remote monitoring unit.

2. The heat treatment control system for bearing steel ball production according to claim 1, characterized in that: The distributed node unit includes a temperature sensor interface, a heating drive circuit, and a cooling control circuit. The output of the temperature sensor interface unit is connected to the input of the central control unit via an SPI interface. The input of the heating drive circuit receives the PWM signal from the central control unit, and its output is connected to the graphite resistance heater via a high-voltage cable. The input of the cooling control circuit receives the PWM signal from the central control unit, and its output is connected to the flow control valve drive circuit via a control cable.

3. The heat treatment control system for bearing steel ball production according to claim 2, characterized in that: The heating drive circuit includes a first optocoupler, a high-frequency inverter, a power amplifier, a DC power supply, and a graphite resistance heater. The anode of the first optocoupler is connected to the central control unit to receive a PWM signal, the cathode is grounded, the collector is connected to the inverter power supply Vcc, and the emitter is connected to the input terminal of the high-frequency inverter. The high-frequency inverter uses an IGBT module. The collector of the IGBT module is connected to the positive terminal of the DC power supply, the emitter is connected to the negative terminal of the DC power supply and one end of the graphite resistance heater, and the gate is connected to the output side of the first optocoupler. The drain of the power amplifier is connected to the emitter of the IGBT module, the source is connected to the other end of the graphite resistance heater and grounded, and the gate is connected to the gate of the IGBT module.

4. A heat treatment control system for producing bearing steel balls according to claim 3, characterized in that: The IGBT module and the gate of the power amplifier are connected by a 10Ω current-limiting resistor.

5. A heat treatment control system for bearing steel ball production according to claim 2, characterized in that: The cooling control circuit includes a second optocoupler isolator and a flow control valve drive circuit. The anode of the second optocoupler is connected to the central control unit, the cathode is grounded, the collector is connected to the power supply of the flow control valve drive circuit, and the emitter is connected to the control input of the flow control valve drive circuit. The flow control valve drive circuit uses a solenoid valve driver. The input terminal IN of the solenoid valve driver is connected to the output side of the second optocoupler isolator, the output terminal OUT of the solenoid valve driver is connected to the cooling water valve coil, and the power supply terminals Vcc and GND of the solenoid valve driver are connected to the positive and negative terminals of the system power supply, respectively.

6. A heat treatment control system for producing bearing steel balls according to claim 1, characterized in that: The central control unit includes a processor, a PID control circuit, and a communication interface circuit. The processor uses an STM32F769 to perform multi-node temperature control and data calculation. The processor's input receives temperature data signals from each distributed node, and its output sends PWM signals to the heating drive circuit and cooling control circuit through the PID control circuit. The communication interface circuit's input receives data signals from the distributed nodes, and its output connects to the distributed nodes via a CAN bus and to a remote monitoring unit via a wireless communication network.

7. A heat treatment control system for producing bearing steel balls according to claim 6, characterized in that: The STM32F769's TIM1_CH1 is connected to the input of the first optocoupler isolator; the STM32F769's TIM2_CH1 is connected to the input of the second optocoupler isolator.

8. A heat treatment control system for producing bearing steel balls according to claim 1, characterized in that: The remote monitoring unit includes a data acquisition and processing subunit, a user interface subunit, and an alarm subunit. The input terminal of the data acquisition and processing subunit receives data signals from the central control unit, and the output terminal sends processed data to the user interface subunit and the alarm subunit. The input terminal of the user interface subunit receives the processed data from the data acquisition and processing subunit, and the output terminal sends user operation commands to the central control unit. The input terminal of the alarm subunit receives abnormal data from the data acquisition and processing subunit, and the output terminal sends alarm information to the user interface and maintenance personnel.

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