Isothermal tempering furnace production line and control method thereof

Abstract

The present application relates to the technical field of constant speed control of tempering furnace production line, and discloses a constant speed tempering furnace production line and a control method thereof, wherein the constant speed tempering furnace production line is characterized in that: the front and rear ends of the chain plate conveyor are fixedly arranged at the front and rear positions of the furnace body; the heating mechanism is arranged at the upper left and right sides of the furnace body; the hot air mixing mechanism is fixedly arranged at the upper middle position of the furnace body; the furnace door lifting mechanism is provided with two; the cooling mechanism is fixedly arranged at the upper rear end of the chain plate conveyor; and the control method of the constant speed tempering furnace production line is characterized in that: step one is setting the tempering process parameters; step two is the constant speed operation of the chain plate conveyor and the internal temperature coordinated control of the furnace body; and step three is the tempering and cooling of the transmission shaft head. The present application has the beneficial effects that: the quality problems of uneven hardness of workpieces after tempering, incomplete elimination of internal stress and easy deformation and cracking of traditional tempering equipment are solved; and the production efficiency of workpieces is greatly improved, and the present application is suitable for the production of large quantities of automobile parts.

Description

Technical Field

[0001] This invention relates to the field of constant velocity control technology for tempering furnace production lines, and particularly to a constant velocity tempering furnace production line and its control method. Background Technology

[0002] In the machining and metal heat treatment industries, tempering is a key process step to eliminate quenching internal stress in workpieces, stabilize dimensions, and improve material toughness and hardness. With the increasing demands for product consistency, production efficiency, and automation in industrial production, traditional intermittent tempering furnaces or ordinary continuous tempering equipment are no longer sufficient to meet the needs of large-scale production.

[0003] Currently, there are two main methods for conveying workpieces in conventional continuous tempering furnaces: the first is the conveyor belt method, in which sprockets are fixed at both ends of the furnace body's inlet and outlet, and the conveyor belt is fixed on both sides of the chain. The sprockets drive the chain to rotate, thereby realizing the conveying operation of the conveyor belt; the second is the multi-roller drive method, in which multiple roller groups are laid flat on the workpiece conveying channel of the entire furnace body, and the workpiece is conveyed by the synchronous operation of all rollers driven by an external motor.

[0004] However, the aforementioned existing technologies have many drawbacks. The conveyor belt is prone to damage under prolonged high-temperature conditions. Since the conveyor belt is driven only by a pair of sprockets located at both ends of the furnace body, its conveying stroke within the furnace is relatively long. Long-term exposure to workpiece pressure and high-temperature radiation easily leads to irregular deformation, resulting in relatively poor operational stability and a tendency to vibrate. The multi-roller drive system has a complex overall structure, requiring strict control of the gaps between each roller during production. When a conveying failure occurs in the furnace body, it is necessary to shut down and cool down, resulting in high maintenance costs.

[0005] Furthermore, existing continuous tempering production lines generally suffer from unstable workpiece conveying speed and uneven workpiece movement. Traditional continuous tempering furnaces often use ordinary conveying mechanisms, which are prone to fluctuations and uneven speeds. The residence time of workpieces in the high-temperature zone within the furnace varies, leading to uneven hardness and incomplete stress relief after tempering, resulting in quality problems such as deformation and cracking. Some tempering equipment operates intermittently, requiring manual loading and unloading and batch processing, which is cumbersome, results in poor production continuity, low overall production efficiency, and high labor costs. The temperature field within the furnace does not match the workpiece movement speed, leading to poor temperature control accuracy and difficulty in ensuring product consistency. The equipment has a low degree of automation, with poor coordination between feeding, conveying, and discharging, easily causing material jams and accumulation, insufficient operational stability, and high energy consumption. To address the aforementioned technical problems in the existing technology, the inventors have developed a constant-speed tempering furnace production line and its control method, which effectively solves the above-mentioned technical problems in the existing technology. Summary of the Invention

[0006] To address the problems in the prior art, this invention provides a constant-speed tempering furnace production line and its control method. Through the arrangement of the furnace body, chain conveyor, heating mechanism, hot mixing mechanism, furnace door lifting mechanism, cooling mechanism, and control system, this invention forms a complete closed-loop control system with a PLC control module as the core, which includes parameter input, status acquisition, collaborative calculation, precise execution, and safe redundant temperature control.

[0007] This invention provides a constant-speed tempering furnace production line, including a furnace body, safety railings, and a chain conveyor. The furnace body is a hollow, closed square shape. Two safety railings are fixedly installed at the front and rear ends of the furnace body. The chain conveyor is fixedly installed at both ends at the front and rear ends of the furnace body, with the chain plates inside the furnace body. The chain conveyor is used for constant-speed transport of the drive shaft head. A heating mechanism is located on the upper left and right sides of the furnace body, providing the heat required for tempering. A hot air mixing mechanism is fixedly installed in the upper middle position of the furnace body, uniformly mixing the heat generated by the heating mechanism. Two furnace door lifting mechanisms are provided, one... One door is fixedly installed at the upper front end of the furnace body, and the other is fixedly installed at the upper rear end of the furnace body; the furnace door lifting mechanism opens or closes the furnace body by raising and lowering the furnace door; the cooling mechanism is fixedly installed at the upper rear end of the chain conveyor, and is used to rapidly cool the head of the tempering drive shaft; there are two proximity switches, one fixedly installed at the right rear side of the safety fence at the front end of the furnace body, and the other fixedly installed at the right front side of the safety fence at the rear end of the furnace body, with the sensing head of the proximity switch aligned with the chain conveyor; the control system is fixedly installed at the bottom left side of the front end of the furnace body, and is used to achieve constant speed operation of the chain conveyor and coordinated temperature control inside the furnace body.

[0008] The furnace body includes a furnace shell, and a furnace lining is built on the inner wall of the furnace shell. The furnace lining is made of a mixture of refractory fiber and lightweight insulating bricks. The heat-concentrating plate is fixedly installed on the inner wall of the furnace lining by a fixing keel. The heat-concentrating plate is a smooth stainless steel plate.

[0009] The safety fence includes a fence frame, which is a hollow square body welded from square steel. The fence panel is fixedly installed on the outer side of the fence frame, and the surface of the fence panel has uniformly spaced convection heat exchange holes.

[0010] The chain conveyor includes a servo motor, which is fixedly mounted on the left side of the front safety fence frame of the furnace shell, near the upper part. The servo motor passes through the fence plate, and its power output shaft is fixedly connected to the drive shaft. Bearings are fixedly mounted at both ends of the drive shaft, which is then fixedly mounted on the upper lateral inner side of the front safety fence frame of the furnace shell via these bearings. Drive sprockets are symmetrically fixedly mounted on the drive shaft, and the left end of the drive shaft passes through the outer side of the bearing seat and is fixedly connected to the power output shaft of the servo motor. Bearings are fixedly mounted at both ends of the driven shaft, which is then fixedly mounted on the upper lateral inner side of the rear safety fence frame of the furnace shell via these bearings. Driven sprockets are symmetrically mounted on the driven shaft. A conveyor chain meshes between the drive sprockets and the driven sprockets, and chain plates are evenly and equally spaced fixedly mounted on the conveyor chain. The conveyor chain passes through the furnace openings at the front and rear ends of the furnace body.

[0011] The chain plate includes a chain plate body, which is a flat plate. A convex plate is vertically fixed in the middle of the chain plate body, and honeycomb holes are evenly opened on the chain plate body on both sides of the convex plate.

[0012] The heating mechanism includes a protective cover, which is U-shaped and has heat dissipation holes on the left and right sides. The protective cover is fixedly installed on the upper left and right edges of the furnace shell. The heating tube is installed at the corresponding position on the protective cover. The heating tube passes through the furnace shell, furnace lining and heat-concentrating plate and extends into the interior of the furnace body. The wiring terminal of the heating tube is located at the lower part of the protective cover. The thermocouple is installed in the middle of the upper part of the furnace shell. There are two thermocouples symmetrically arranged front and back. The thermocouple passes through the furnace shell, furnace lining and heat-concentrating plate and extends into the interior of the furnace body.

[0013] The heat mixing mechanism includes a first fan motor and a second fan motor. The first fan motor and the second fan motor are fixedly installed in the upper middle position of the furnace shell by a motor bracket. The first fan motor and the second fan motor are arranged symmetrically front and back. The power output shafts of the first fan motor and the second fan motor extend into the interior of the furnace body. Impellers are fixedly installed on the bottom power output shafts of the first fan motor and the second fan motor. The first fan motor and the second fan motor are fixedly connected to the PLC control module through signal lines. The first fan motor and the second fan motor are fixedly connected to the internal power supply of the control cabinet through cables.

[0014] The furnace door lifting mechanism includes a fixed frame, with two sets of fixed frames arranged symmetrically on the left and right. One set is fixedly installed at the upper front end of the furnace shell, and the other set is fixedly installed at the upper rear end of the furnace shell. Shaft seats are fixedly installed at both ends of the sprocket shaft, and the shaft seats are fixedly installed on the inner sides of the two symmetrically arranged fixed frames. The sprockets are symmetrically mounted on the sprocket shaft. Four cylinders are provided, with two sets arranged symmetrically on the left and right. One set is located near the front end of the furnace shell, and the other set is fixedly installed near the rear end of the furnace shell. The distance between the two symmetrically arranged cylinders is... The symmetrically arranged sprockets are spaced equally apart; four chains are provided, one end of which is fixedly connected to the upper part of the furnace door, and the other end of which passes around the sprocket and is fixedly connected to the outer end of the cylinder's telescopic rod, with the chain meshing with the sprocket; the furnace door is larger than the furnace opening, and the furnace door fits against the outer wall of the furnace shell, located directly above the furnace opening; the telescopic rods of the set of cylinders located on the upper part of the furnace shell near the front face forward, and the telescopic rods of the set of cylinders located on the upper part of the furnace shell near the rear face backward; the four cylinders are fixedly connected to the PLC control module via signal lines, and the four cylinders are fixedly connected to the air source solenoid valve via air pipes.

[0015] The cooling mechanism includes an axial flow fan and a fan frame. The fan frame is a bent U-shaped plate and is horizontally fixed on the rear fence frame of the furnace body. The axial flow fan is symmetrically fixed on the fan frame. The axial flow fan is fixedly connected to the PLC control module through a signal line and to the internal power supply of the control cabinet of the control system through a cable.

[0016] The proximity switch is fixedly mounted on the upper right inner side of the fence frame via a Z-shaped bending plate; the proximity switch is fixedly connected to the PLC control module via a signal line.

[0017] The control system includes a control cabinet, which is fixedly installed at the bottom left of the front of the furnace body. The display screen is located at the upper middle of the front side of the control cabinet. The temperature controller is fixedly installed at the lower left of the display screen. The PLC control module is located inside the control cabinet behind the display screen. The AC contactor is fixedly installed at the right side of the temperature controller. The display screen and the temperature controller are fixedly connected to the PLC control module via signal lines.

[0018] This invention provides a control method for a constant-rate tempering furnace production line, mainly including the following steps:

[0019] Step 1: Setting the tempering process parameters: According to the tempering process requirements of the drive shaft head, set the tempering temperature (target temperature) inside the furnace through the display screen of the control system, and at the same time set the running speed (conveyor speed) of the chain conveyor servo motor; at the same time, set the tempering time of the drive shaft head according to the tempering process requirements of the drive shaft head.

[0020] Step Two: Coordinated Control of Constant Speed ​​Operation of the Chain Conveyor and Internal Furnace Temperature: After setting the furnace tempering temperature and chain conveyor speed in Step One, the robotic arm places the quenched drive shaft head onto the chain conveyor in one go. After the robotic arm moves away from the proximity switch at the front of the furnace, the proximity switch senses the drive shaft head and sends a position signal to the PLC control module. Simultaneously, the PLC control module sends lifting control signals to the furnace door lifting mechanisms at the front and rear ends of the furnace. Upon receiving the signal, the solenoid valve of the furnace door lifting mechanism cylinder opens, and the cylinder begins to retract, pulling the chain towards the center of the furnace. Through the rotational meshing of the chain and sprocket, the furnace door is pulled along the front end of the furnace. Alternatively, the rear sidewall may move upwards, opening the furnace door. At this time, the front and rear doors of the furnace body open simultaneously. When the cylinder's retraction stroke reaches the maximum stroke of the magnetic switch within the cylinder, the magnetic switch sends a limit signal to the PLC control module. Upon receiving the cylinder's retraction limit signal, the PLC control module sends a start control signal to the servo motor of the chain conveyor. The chain conveyor begins constant-speed operation and sends a closing control signal to the solenoid valve supplying air to the cylinder. Simultaneously, the PLC control module sends start control signals to the first and second fan motors of the heat mixing mechanism. The high-speed rotation of the impellers at the bottom of the first and second fan motors mixes the heat inside the furnace body. Meanwhile, the robotic arm... The chain conveyor continues to place the quenched drive shaft head onto the chain plate during its operating cycle. For each cycle, the robotic arm places the quenched drive shaft head onto the chain plate in one go. Based on the chain conveyor's operating speed and the time required for it to reach the rear end of the furnace, the PLC control module sends a stop signal to the chain conveyor's servo motor. The chain conveyor stops, and simultaneously sends an opening control signal to the solenoid valves supplying air to the furnace door lifting mechanism cylinders at the front and rear ends of the furnace. The cylinder's extension rod begins to extend, and due to the furnace door's own weight, the meshing of the chain and sprockets slowly lowers the furnace door to the top of the chain plate's convex plate. When the furnace body is in contact with the thermocouple, the lifting mechanisms of the furnace door at the front and rear ends close simultaneously. At the same time, the PLC control module feeds back the furnace body internal temperature value detected in real time by the thermocouple through the temperature controller. The PLC control module uses the PID control algorithm built into the temperature controller to calculate and compare the temperature with the set tempering temperature. When the furnace body internal tempering temperature is lower than the set tempering temperature, the PLC control module, together with the temperature controller, sends a control signal to the power controller to increase the power of the heating tube. When the furnace body internal tempering temperature is higher than the set tempering temperature, the PLC control module, together with the temperature controller, sends a control signal to the power controller to decrease the power of the heating tube, so that the temperature inside the furnace body is always consistent with the set tempering temperature.

[0021] Step 3: Tempering and Cooling of the Drive Shaft Head: After the constant speed operation of the chain conveyor and the constant temperature of the furnace body are completed in Step 2, the temperature inside the furnace body will be consistent with the set tempering temperature. At this time, the PLC control module will start recording the tempering time of the drive shaft head. When the tempering time of the drive shaft head reaches the set tempering time, the PLC control module will send an opening control command to the solenoid valves of the furnace door lifting mechanism cylinders at the front and rear ends of the furnace body. The cylinder extension rod will then retract, pulling the chain towards the middle of the furnace body. The chain and sprockets rotate to raise the furnace doors at the front and rear ends of the furnace body. At the same time, the PLC control module sends a start control signal to the servo motor of the chain conveyor, and the chain conveyor runs at a constant speed. When the drive shaft head, which has been tempered, moves to the position of the proximity switch at the rear end of the furnace body, the proximity switch detects the position signal of the drive shaft head and sends it to the PLC control module. The PLC control module sends a start control signal to the axial flow fan of the cooling mechanism, and the two axial flow fans simultaneously blow cooling air onto the surface of the drive shaft head for rapid cooling.

[0022] In step two, the width of the chain plate is the distance the chain plate travels in one cycle.

[0023] In step two, the constant speed operation control method of the chain conveyor is as follows: The PLC control module calculates the instantaneous operating speed of the chain conveyor in real time based on the preset operating speed of the chain conveyor and the distance between the proximity switches at the front and rear of the furnace body. By comparing the preset operating speed of the chain conveyor with the instantaneous operating speed, the PLC control module sends a dynamic frequency modulation signal to the driver to dynamically adjust the speed of the chain conveyor servo motor, so that the chain conveyor always operates at a constant speed.

[0024] In step two, during the coordinated temperature control process inside the furnace, an AC contactor is installed on the main circuit of the heating tube. During normal operation, the heating circuit of the heating tube is controlled by a thyristor. Once a phase of the thyristor is broken down, the temperature controller alarms and the temperature controller immediately switches to the redundant temperature control system.

[0025] The beneficial effects of the present invention are as follows: The present invention, through the setting of furnace body, chain conveyor, heating mechanism, hot mixing mechanism, furnace door lifting mechanism, cooling mechanism and control system, forms a complete closed-loop control system with PLC control module as the core, which includes parameter input, status acquisition, collaborative calculation, precise execution and safe redundant temperature control.

[0026] 1. Achieve high-precision constant-speed operation of the chain conveyor: After the operator sets the conveying speed through the display screen, the PLC control module calculates the instantaneous running speed of the chain conveyor in real time by combining the spacing data of the proximity switches at the front and rear ends. It compares the speed with the preset speed and outputs a dynamic frequency modulation signal to the driver. The driver adjusts the speed of the servo motor in real time, which completely solves the problems of unstable workpiece conveying speed and uneven travel speed in traditional continuous tempering production lines. It ensures that the moving speed of all drive shaft heads in the furnace is completely consistent, and ensures that the residence time of each workpiece in the high-temperature zone of the furnace is completely uniform, eliminating the difference in tempering quality of workpieces from the conveying dimension.

[0027] 2. Achieving high-precision constant temperature control within the furnace: Real-time furnace temperature collected by thermocouples is transmitted to the PLC control module via a temperature controller. After the temperature difference is calculated using the temperature controller's built-in PID algorithm, the PLC control module sends a power adjustment command to the power controller to dynamically adjust the output power of the heating tubes, ensuring that the furnace temperature remains stable at the preset tempering temperature. Simultaneously, the AC contactor on the main heating circuit, in conjunction with the temperature controller's redundant switching function, forms dual temperature control protection, preventing overheating, heating runaway, and other faults. This solves the shortcomings of traditional tempering furnaces, such as poor temperature control accuracy and mismatch between the temperature field and the workpiece travel speed, ensuring a uniform and stable temperature field within the furnace.

[0028] 3. Automated linkage control of various mechanisms in the constant-speed tempering production line: This control system can automatically coordinate the timing of the furnace door lifting mechanism, hot air mixing mechanism, and cooling mechanism. After the workpiece is placed on the chain conveyor, the front proximity switch triggers the furnace door to open automatically. After the furnace door reaches its position, the chain conveyor and hot air mixing fan automatically start. After the workpiece is conveyed to the designated position, the furnace door automatically closes for heat preservation. After the tempering timer ends, the front and rear furnace doors automatically rise, the chain conveyor automatically starts to transport the workpiece, and when the workpiece reaches the rear proximity switch position, the axial flow fan is automatically triggered to complete the rapid cooling. The entire process requires no manual intervention, completely avoiding material jamming and accumulation problems caused by poor connection between feeding, conveying, and discharging, significantly improving the automation level of the production line and reducing labor costs.

[0029] By combining constant speed operation and constant furnace temperature control in the above-mentioned constant speed tempering production line, the quality problems of uneven workpiece hardness, incomplete elimination of internal stress, and easy deformation and cracking after tempering in traditional tempering equipment are completely solved, and the product consistency is greatly improved. At the same time, the hot air mixing and precise temperature control mode achieves energy saving and consumption reduction, improves overall production efficiency while ensuring production continuity, significantly improves operational stability, and the overhaul cycle can reach a service life of no less than 6 years. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of the present invention;

[0031] Figure 2 For the present invention Figure 1Cross-sectional view;

[0032] Figure 3 For the present invention Figure 1 Side view of the furnace body;

[0033] Figure 4 This is a schematic diagram of the chain plate structure of the chain plate conveyor of the present invention;

[0034] Figure 5 For the present invention Figure 2 A partial enlarged view of the heating mechanism;

[0035] Figure 6 For the present invention Figure 1 Enlarged view of the back end;

[0036] Figure 7 For the present invention Figure 2 Enlarged views of the mid-to-back-end and front-end areas;

[0037] Figure 8 This is a perspective view of the thermal mixing mechanism of the present invention;

[0038] Figure 9 This is a front view of the upper part of the control cabinet of the control system of the present invention;

[0039] Figure 10 This is a flowchart illustrating the coordinated control of constant speed and temperature in the constant speed tempering production line of the present invention.

[0040] Markings in the diagram: 1. Furnace body; 11. Furnace shell; 12. Furnace lining; 13. Heat-collecting plate; 14. Furnace opening; 2. Safety fence; 21. Fence frame; 22. Fence plate; 23. Convection heat exchange hole; 3. Chain conveyor; 31. Servo motor; 32. Drive shaft; 33. Drive sprocket; 34. Driven shaft; 35. Driven sprocket; 36. Chain plate; 361. Chain plate body; 362. Convex plate; 363. Honeycomb hole; 37. Conveyor chain; 4. Heating mechanism; 41. Protective cover; 42. Heating tube; 43. Thermocouple; 5. Heat mixer. 51. Fan motor 1, 52. Fan motor 2, 53. Impeller, 6. Furnace door lifting mechanism, 61. Fixing frame, 62. Protective plate, 63. Sprocket shaft, 64. Shaft seat, 65. Sprocket, 66. Cylinder, 67. Chain, 68. Furnace door, 7. Cooling mechanism, 71. Axial flow fan, 72. Fan frame, 8. Proximity switch, 9. Control system, 91. Control cabinet, 92. Display screen, 93. Temperature controller, 94. PLC control module, 95. AC contactor, 96. Driver, 97. Power controller. Detailed Implementation

[0041] The present invention will be further described below with reference to specific embodiments. These embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0042] This invention provides a constant-rate tempering furnace production line:

[0043] like Figure 1 , 2 As shown in Figure 3, the furnace body 1 is a hollow, closed square shape. The furnace body 1 includes a furnace shell 11. A furnace lining 12 is built on the inner wall of the furnace shell 11. The furnace lining 12 is made of a mixture of refractory fiber and lightweight insulating bricks. A heat-concentrating plate 13 is fixedly installed on the inner wall of the furnace lining 12 by a fixed keel. The heat-concentrating plate 13 is a smooth stainless steel plate.

[0044] The furnace body 1 is constructed using welded steel profiles, with the outer side panels being a single 83.0mm thick cold-rolled steel plate bent and wrapped around the surface. The furnace body surface is aesthetically pleasing with no weld points. The main purpose of this design is to improve the overall rigidity of the furnace body 1, providing stable support for the construction of the furnace lining 12 and the fixing of the heat-concentrating plate 13.

[0045] The furnace lining is constructed using a mixture of refractory fiber and lightweight insulating bricks. This structure provides excellent insulation, rapid heating, and minimal heat loss. Under normal operating conditions, the overhaul period is no less than 6 years.

[0046] The furnace lining described above is made of refractory fiber with an insulation thickness of 240mm. The main purpose of this is twofold: firstly, to provide insulation, and secondly, to prevent heat loss from the interior of the furnace body 1, thus providing a constant tempering temperature for the tempering treatment of the drive shaft head.

[0047] The main purpose of setting up the heat-collecting plate 13 is twofold: firstly, to collect heat; and secondly, to reflect heat to the center of the furnace body 1 by utilizing the reflective properties of the surface of the heat-collecting plate 13, thereby achieving energy saving and consumption reduction.

[0048] like Figure 1 , 2 As shown in Figures 6 and 7, there are two safety fences 2, which are fixedly installed at the front and rear ends of the furnace body 1 respectively. The safety fence 2 includes a fence frame 21, which is a hollow square body welded from square steel. The fence plate 22 is fixedly installed on the outer side of the fence frame 21. The surface of the fence plate 22 has uniformly cut convection heat exchange holes 23.

[0049] The safety fence 2 serves two purposes: firstly, it isolates operators from contact with the chain conveyor 3, providing safety protection; secondly, the fence frame 21 of the safety fence 2 provides fixed support for the drive shaft 32 and driven shaft 34 of the chain conveyor 3, and also provides a platform for the fixed installation of the servo motor 31.

[0050] like Figure 1 , 2As shown in Figures 6, 7, and 10, the front and rear ends of the chain conveyor 3 are fixedly installed at the front and rear positions of the furnace body 1. The chain plates of the chain conveyor 3 are installed inside the furnace body 1. The chain conveyor 3 is used to convey the shaft head of the drive shaft at a constant speed. The chain conveyor 3 includes a servo motor 31, which is fixedly installed on the left side of the fence frame 21 of the front safety fence 2 of the furnace shell 11, near the upper part. The servo motor 31 passes through the fence plate 22, and the power output shaft of the servo motor 31 is fixedly connected to the drive shaft 32. Shaft seats are fixedly installed at both ends of the drive shaft 32, and the drive shaft 32 is fixedly installed on the front fence frame 2 of the furnace shell 11 through the shaft seats at both ends. At the upper inner side of the furnace body 1, drive sprockets 33 are symmetrically fixed on drive shaft 32. The left end of drive shaft 32 passes through the outer side of bearing seat and is fixedly connected to the power output shaft of servo motor 31. Both ends of driven shaft 34 are fixedly provided with bearing seats. Driven shaft 34 is fixedly provided at the upper inner side of rear end fence frame 21 of furnace shell 11 through the bearing seats at both ends. Driven sprockets 35 are symmetrically provided on driven shaft 34. A conveyor chain 37 is meshed between drive sprockets 33 and driven sprockets 35. Chain plates 36 are evenly and equally spaced fixed on conveyor chain 37. Conveyor chain 37 passes through the furnace openings 14 at the front and rear ends of furnace body 1.

[0051] The above-mentioned arrangement of servo motor 31, drive shaft 32, drive sprocket 33, driven shaft 34, driven sprocket 35, chain plate 36 and conveyor chain 37 forms a conveying mechanism for conveying the shaft head of the transmission shaft at constant speed.

[0052] The above-mentioned configuration of servo motor 31, proximity switch 8, driver 96, and PLC control module 94 allows the PLC control module 94 to calculate the instantaneous running speed of the chain conveyor 3 in real time, based on the preset running speed of the chain conveyor 3 and the distance between the proximity switches 8 at the front and rear ends of the furnace body 1. By comparing the preset running speed of the chain conveyor 3 with the instantaneous running speed, the PLC control module 94 sends a dynamic frequency modulation signal to the driver 96 to dynamically adjust the speed of the servo motor 31 of the chain conveyor 3, ensuring that the chain conveyor 3 always operates at a constant speed.

[0053] like Figure 4 As shown, the chain plate 36 includes a chain plate body 361, which is a flat plate. A protruding plate 362 is vertically fixed in the middle position of the chain plate body 361. Honeycomb holes 363 are evenly opened on the chain plate body 361 on both sides of the protruding plate 362.

[0054] The main purpose of the above arrangement is that the chain plate body 361 on both sides of the convex plate 362 is used to place the drive shaft head. With the help of the honeycomb holes 363, when the drive shaft head is tempered inside the furnace body 1, the tempering heat inside the furnace body 1 can fully contact the surface of the drive shaft head through the honeycomb holes 363, so that the tempering hardness of the drive shaft head is uniform and the internal stress of the drive shaft head is completely eliminated.

[0055] like Figure 2 and 5 As shown, the heating mechanism 4 is located on the upper left and right sides of the furnace body 1. The heating mechanism 4 is used to provide the heat required for tempering into the furnace body 1. The heating mechanism 4 includes a protective cover 41, which is U-shaped and has heat dissipation holes on the left and right sides. The protective cover 41 is fixedly installed on the upper left and right edges of the furnace shell 11. The heating tube 42 is installed at the corresponding position of the protective cover 41. The heating tube 42 passes through the furnace shell 11, the furnace lining 12 and the heat-concentrating plate 13 and extends into the interior of the furnace body 1. The wiring terminal of the heating tube 42 is located at the lower part of the protective cover 41. Thermocouple 43 is located in the middle of the upper part of the furnace shell 11. There are two thermocouples 43 arranged symmetrically at the front and back. The thermocouple 43 passes through the furnace shell 11, the furnace lining 12 and the heat-concentrating plate 13 and extends into the interior of the furnace body 1. The thermocouple 43 is fixedly connected to the heating circuit inside the control cabinet 91 of the control system 9 through a connecting wire.

[0056] The aforementioned protective cover 41 serves two purposes: firstly, it provides dust protection for the heating tube 42; secondly, the heat dissipation holes on the left and right sides of the protective cover 41 allow the heat generated by the heating element on the upper part of the heating tube 42 to be dissipated and discharged.

[0057] The above-mentioned setup of heating tube 42, thermocouple 43, temperature controller 93, power controller 97, and PLC control module 94 allows the PLC control module 94 to receive real-time feedback from the temperature controller 93 on the internal temperature of the furnace body 1 detected by the thermocouple 43. The temperature controller 93 uses a built-in PID control algorithm to work with the PLC control module 94 to calculate and compare the temperature with the set tempering temperature. When the internal tempering temperature of the furnace body 1 is lower than the set tempering temperature, the PLC control module 94, in conjunction with the temperature controller 93, sends a control signal to the power controller 97 to increase the power of the heating tube 42. When the internal tempering temperature of the furnace body is higher than the set tempering temperature, the PLC control module 94, in conjunction with the temperature controller 93, sends a control signal to the power controller 97 to decrease the power of the heating tube 42, ensuring that the internal temperature of the furnace body 1 always matches the set tempering temperature.

[0058] like Figure 1 , 2As shown in Figure 8, the hot air mixing mechanism 5 is fixedly installed at the upper middle position of the furnace body 1. The hot air mixing mechanism 5 is used to uniformly mix the heat generated by the heating mechanism 4. The hot air mixing mechanism 5 includes a fan motor 51 and a fan motor 52. The fan motor 51 and the fan motor 52 are fixedly installed at the upper middle position of the furnace shell 11 through a motor bracket. The fan motor 51 and the fan motor 52 are arranged symmetrically front and back. The power output shafts of the fan motor 51 and the fan motor 52 extend into the interior of the furnace body 1. Impellers 53 are fixedly installed on the bottom power output shafts of the fan motor 51 and the fan motor 52. The fan motor 51 and the fan motor 52 are fixedly connected to the PLC control module 94 through signal lines. The fan motor 51 and the fan motor 52 are fixedly connected to the internal power supply of the control cabinet 91 through cables.

[0059] With the arrangement of the fan motor 51, fan motor 52 and impeller 53, when the heating tube of the heating mechanism 4 starts to heat, the high-speed rotation of the impeller 53 can mix the heat generated by the heating tube 42, thereby improving the uniformity of heat inside the furnace body 1.

[0060] The opening and closing of the aforementioned fan motor 1 51 and fan motor 2 52 are automatically controlled by the PLC control module 94. The PLC control module 94 starts the fan motor 1 51 and fan motor 2 52, and the trigger signal is at the same time that the heating tube of the heating mechanism 4 starts heating.

[0061] like Figure 1 , 2As shown in Figure 6, there are two furnace door lifting mechanisms 6, one fixedly installed at the upper front end of the furnace body 1, and the other fixedly installed at the upper rear end of the furnace body 1. The furnace door lifting mechanism 6 opens or closes the furnace body 1 by lifting and lowering the furnace door. The furnace door lifting mechanism 6 includes a fixing frame 61, which is provided in two sets. Two fixing frames 61 are arranged symmetrically on the left and right as one set. One set is fixedly installed at the upper front end of the furnace shell 11, and the other set is fixedly installed at the upper rear end of the furnace shell 11. Shaft seats 64 are fixedly installed at both ends of the sprocket shaft 63. The shaft seats 64 are fixedly installed on the inner side of the two symmetrically arranged fixing frames 61. The sprockets 35 are symmetrically arranged on the sprocket shaft 63. There are four cylinders 66, which are arranged symmetrically on the left and right as one set. One set is located near the fixing frame 61 at the front end of the furnace shell 11, and the other set is fixedly installed near the fixing frame 61 at the rear end of the furnace shell 11. The fixed bracket 61 at the rear end of the furnace shell 11 is positioned as follows: the distance between the two symmetrically arranged cylinders 66 is equal to the distance between the symmetrically arranged sprockets 35; four chains 67 are provided, one end of which is fixedly connected to the upper part of the furnace door 68, and the other end of which passes around the sprocket 35 and is fixedly connected to the outer end of the telescopic rod of the cylinder 66, with the chain 67 meshing with the sprocket 35; the furnace door 68 is larger than the furnace opening 14, and the furnace door 68 is attached to the outer wall of the furnace shell 11, located directly above the furnace opening 14; the telescopic rods of a group of cylinders 66 located near the front end of the upper part of the furnace shell 11 face forward, and the telescopic rods of a group of cylinders 66 located near the rear end of the upper part of the furnace shell 11 face backward; the four cylinders 66 are fixedly connected to the PLC control module 94 via signal lines, and the four cylinders 66 are fixedly connected to the gas source solenoid valve via air pipes.

[0062] The aforementioned installation of furnace door lifting mechanisms 6 at the front and rear ends of the furnace body 1 serves two purposes. Firstly, the lifting and lowering of the two furnace door lifting mechanisms 6 provides trigger signals for the opening and closing of the chain conveyor 3. Specifically, when the chain conveyor 3 is running, the furnace doors 68 of the two furnace door lifting mechanisms 6 are open; when the furnace doors 68 of the two furnace door lifting mechanisms 6 are closed, the chain conveyor 3 is stopped. This achieves a safety interlock function between the furnace door lifting mechanisms 6 and the chain conveyor 3. Secondly, when the furnace doors 68 of the two furnace door lifting mechanisms 6 are closed, the tempering temperature inside the furnace body 1 is kept constant. Conversely, when the furnace doors 68 of the two furnace door lifting mechanisms 6 are open, the chain conveyor 3 can normally transport the drive shaft head.

[0063] The aforementioned arrangement of sprocket shaft 63, symmetrically arranged sprockets 65, double chains 67, and double cylinders 66 improves the uniformity of the lifting and lowering force on the furnace door 68, making the raising and lowering of the furnace door 68 more stable.

[0064] like Figure 1 , 2As shown in Figures 6 and 7, the cooling mechanism 7 is fixedly installed at the upper rear end of the chain conveyor 3. The cooling mechanism 7 is used to rapidly cool the head of the tempering drive shaft. The cooling mechanism 7 includes an axial flow fan 71 and a fan frame 72. The fan frame 72 is a bent U-shaped plate. The fan frame 72 is horizontally fixed on the rear end fence frame 21 of the furnace body 1. The axial flow fan 71 is symmetrically fixed on the fan frame 72. The axial flow fan 71 is fixedly connected to the PLC control module 94 through a signal line. The axial flow fan 71 is fixedly connected to the internal power supply of the control cabinet 91 of the control system 9 through a cable.

[0065] The aforementioned arrangement of axial flow fans 71 and fan frame 72, which are symmetrically arranged on the left and right, enables rapid cooling of the drive shaft head after tempering using dual axial flow fans 71.

[0066] The automatic control of the axial flow fan 71 is triggered by the proximity switch 8 at the rear end of the furnace body 1 (that is, when the chain conveyor 3 transports the tempered drive shaft head to the position of the proximity switch 8 at the rear end of the furnace body 1, the proximity switch 8 at the rear end of the furnace body 1 senses the position signal of the drive shaft head, and the PLC control module 94 receives the position signal of the drive shaft head sensed by the proximity switch 8). The automatic control of the axial flow fan 71 is realized through the PLC control module 94.

[0067] like Figure 1 and 2 As shown, there are two proximity switches 8. One is fixedly installed on the right rear side of the safety fence 2 at the front end of the furnace body 1, and the other is fixedly installed on the right front side of the safety fence 2 at the rear end of the furnace body 1. The sensing head of the proximity switch 8 is aligned with the chain conveyor 3.

[0068] The aforementioned proximity switch 8 is fixed on a Z-shaped bending plate, which is fixedly located on the right rear side of the front fence frame 21 of the furnace body 1 or on the right front side of the rear fence frame 21 of the furnace body 1.

[0069] The proximity switch 8 installed on the right rear side of the safety fence 2 at the front end of the furnace body 1 serves two purposes: firstly, it detects the position of the drive shaft head when the robotic arm places it on the chain plate 36; secondly, it provides an automatic control trigger signal to the PLC control module 94 for the lifting of the furnace door 68 of the furnace door lifting mechanism 6.

[0070] The proximity switch 8 installed on the right front side of the safety fence 2 at the rear end of the furnace body 1 serves to provide an automatic control trigger signal to the PLC control module 94 for the opening and closing of the cooling mechanism 7, thereby realizing automatic linkage control between the cooling mechanism 7 and the PLC control module 94.

[0071] like Figure 9 and 10As shown, the control system 9 is fixedly installed at the bottom left front end of the furnace body 1. The control system 9 is used to achieve constant speed operation of the chain conveyor and coordinated temperature control inside the furnace body. The control system 9 includes a control cabinet 91, which is fixedly installed at the bottom left front end of the furnace body 1. The display screen 92 is installed at the middle of the upper front side of the control cabinet 91. The temperature controller 93 is fixedly installed at the lower left side of the display screen 92. The PLC control module 94 is installed inside the control cabinet 91 behind the display screen 92. The AC contactor 95 is fixedly installed at the right side of the temperature controller 93. The display screen 92 and the temperature controller 93 are fixedly connected to the PLC control module 94 through signal lines.

[0072] The aforementioned display screen 92 serves two purposes: firstly, as a human-machine interface, allowing operators to input core process parameters such as the target tempering temperature inside the furnace, the running speed of the chain conveyor servo motor, and the tempering time of the drive shaft head, according to the tempering process requirements of the drive shaft head; secondly, as a status display interface, synchronously displaying the current operating status of the production line, real-time furnace temperature, conveying speed, and other operating data, facilitating operators to intuitively grasp the equipment's operating conditions.

[0073] The temperature controller 93, as described above, can receive real-time temperature signals detected by thermocouples inside the furnace and feed them back to the PLC control module. Furthermore, its built-in PID control algorithm can work with the PLC control module to calculate and compare the real-time furnace temperature with the preset tempering temperature. Additionally, it has built-in alarm contacts that can trigger an alarm and automatically switch to the redundant temperature control system when a fault such as a thyristor breakdown occurs in the heating circuit, providing redundant protection for temperature control safety.

[0074] The aforementioned configuration of the PLC control module 94 serves as the core control hub of the entire production line. Installed inside the control cabinet behind the display screen, the PLC module performs several functions: First, it receives workpiece position signals from proximity switches, limit signals from cylinder magnetic switches, real-time furnace temperature signals from the temperature controller, and process parameters input by operators via the display screen. Second, it sends start / stop control commands to the cylinder solenoid valves of the furnace door lifting mechanism, the two fan motors of the hot mixing mechanism, the servo motor of the chain conveyor, and the axial flow fan of the cooling mechanism, coordinating the timing of all components on the production line. Third, it performs real-time calculation of the instantaneous operating speed of the chain conveyor, compares it with the preset speed, and outputs a dynamic frequency modulation signal to ensure stable and constant-speed operation of the chain conveyor. Fourth, in the furnace temperature control stage, it outputs heating tube power adjustment commands and simultaneously records the tempering time of the drive shaft head inside the furnace, achieving precise timing control of the tempering process.

[0075] The AC contactor 95 is installed on the right side of the temperature controller inside the control cabinet, on the main circuit of the heating tube, as a hardware-level safety protection component for the heating circuit. Under normal operating conditions, the heating circuit of the heating tube is controlled by a thyristor for routine temperature control. When one phase of the thyristor breaks down unexpectedly, the AC contactor can work with the redundant temperature control system to cut off or protect the main circuit, avoiding over-temperature faults caused by uncontrolled heating circuits and improving the operational safety of the temperature control system.

[0076] The aforementioned settings of the driver 96 are mainly responsible for receiving the dynamic frequency modulation signal sent by the PLC control module, dynamically adjusting the running speed of the chain conveyor servo motor, compensating for possible speed deviations in the operation of the conveyor chain and sprocket through real-time speed adjustment, offsetting speed changes caused by load fluctuations, and ensuring that the chain conveyor always maintains the preset constant speed state.

[0077] The power controller 97, as the power actuator for the heating tube, receives power adjustment signals from the PLC control module. When the actual tempering temperature in the furnace is lower than the preset value, the heating power of the heating tube is increased to raise the furnace temperature; when the actual tempering temperature in the furnace is higher than the preset value, the heating power of the heating tube is reduced to lower the furnace temperature. This dynamically adjusts the output power of the heating tube to keep the furnace temperature stable near the set tempering target value.

[0078] like Figure 1-10 As shown, the present invention provides a control method for a constant-rate tempering furnace production line, which mainly includes the following steps:

[0079] Step 1: Setting the tempering process parameters: According to the tempering process requirements of the drive shaft head, set the tempering temperature (target temperature) inside the furnace body 1 through the display screen 92 of the control system 9, and at the same time set the running speed (conveyor speed) of the servo motor 31 of the chain conveyor 3; at the same time, set the tempering time of the drive shaft head according to the tempering process requirements of the drive shaft head.

[0080] Step Two: Coordinated Control of Constant Speed ​​Operation of the Chain Conveyor and Internal Furnace Temperature: After the tempering temperature of furnace body 1 and the running speed of the chain conveyor are set in Step One, the robotic arm places the quenched drive shaft head onto the chain plate 36 of the chain conveyor 3 in one go. After the robotic arm leaves the proximity switch 8 at the front end of furnace body 1, the proximity switch 8 senses the drive shaft head and sends a position signal to the PLC control module 94. At the same time, the PLC control module 94 sends lifting control signals to the furnace door lifting mechanism 6 at the front and rear ends of furnace body 1. At this time, the solenoid valve of cylinder 66 of furnace door lifting mechanism 6 receives the signal and opens, and cylinder 66 extends its rod. The retraction action begins, pulling chain 67 towards the center of furnace body 1. Through the rotational meshing of chain 67 and sprocket 65, furnace door 68 is pulled upward along the front or rear side wall of the furnace body, thus opening furnace door 68. At this time, furnace doors 68 at the front and rear ends of furnace body 1 open simultaneously. When the retraction stroke of cylinder 66 reaches the maximum stroke of the magnetic switch in cylinder 66, the magnetic switch sends a limit signal of cylinder 66 to PLC control module 94. After receiving the retraction action limit signal of cylinder 66, PLC control module 94 sends a start control signal to servo motor 31 of chain conveyor 3, and chain conveyor 3 begins to move at a constant speed. The system operates and sends a closing control signal to the solenoid valve supplying air to cylinder 66; simultaneously, the PLC control module 94 sends a start control signal to the fan motor 51 and fan motor 52 of the heat mixing mechanism 5, utilizing the high-speed rotation of the impellers 53 at the bottom of fan motors 51 and 52 to mix the heat inside the furnace body 1; at the same time, the robotic arm continues to place the quenched drive shaft head onto the chain plate 36 according to the running rhythm of the chain conveyor 3. For each cycle of the chain conveyor 3, the robotic arm places the quenched drive shaft head onto the chain plate 36 in one go; the PLC control module 94, according to the chain conveyor... The PLC control module 94 sends a stop control signal to the servo motor 31 of the chain conveyor 3 when the running speed of the conveyor 3 is measured and the time required for the chain conveyor 3 to reach the position near the rear end of the furnace body 1. The chain conveyor 3 stops running and at the same time sends an opening control signal to the solenoid valves of the cylinder 66 of the furnace door lifting mechanism 6 at the front and rear ends of the furnace body 1. The telescopic rod of the cylinder 66 begins to extend. At this time, due to the weight of the furnace door 68, the furnace door 68 is slowly lowered to contact the top of the convex plate 362 of the chain plate 36 through the meshing action of the chain 67 and the sprocket 65. At this time, the furnace door lifting mechanism 6 at the front and rear ends of the furnace body 1 closes at the same time.Meanwhile, the PLC control module 94 feeds back the internal temperature value of the furnace body 1, which is detected in real time by the thermocouple 43, to the PLC control module 94 via the temperature controller 93. The temperature controller 93 uses its built-in PID control algorithm to calculate and compare the value with the set tempering temperature. When the internal tempering temperature of the furnace body 1 is lower than the set tempering temperature, the PLC control module 94, in conjunction with the temperature controller 93, sends a control signal to the power controller 97 to increase the power of the heating tube 42. When the internal tempering temperature of the furnace body is higher than the set tempering temperature, the PLC control module 94, in conjunction with the temperature controller 93, sends a control signal to the power controller 97 to decrease the power of the heating tube 42, ensuring that the internal temperature of the furnace body 1 always matches the set tempering temperature. Each cycle of the chain conveyor 3 is equal to the width of the chain plate 36. The constant speed operation control method for the chain conveyor is as follows: PLC control module... 94. Based on the preset running speed of the chain conveyor 3 and the distance between the proximity switches 8 at the front and rear ends of the furnace body 1, the PLC control module 94 calculates the instantaneous running speed of the chain conveyor 3 in real time. The PLC control module 94 compares the preset running speed with the instantaneous running speed and sends a dynamic frequency modulation signal to the driver 96 to dynamically adjust the speed of the servo motor 31 of the chain conveyor 3, ensuring the chain conveyor 3 always operates at a constant speed. During the furnace body internal temperature control process, an AC contactor 95 is installed on the main circuit of the heating tube 42. Under normal operation, the heating circuit of the heating tube 42 is controlled by a thyristor. If one phase of the thyristor breaks down, the temperature controller 93 alarms and immediately switches to the redundant temperature control system.

[0081] Step 3: Tempering and Cooling of the Drive Shaft Head: After the constant speed operation of the chain conveyor 3 in Step 2 and the constant temperature coordination inside the furnace body 1 are completed, the temperature inside the furnace body 1 will be consistent with the set tempering temperature. At this time, the PLC control module 94 will start recording the tempering time of the drive shaft head. When the tempering time of the drive shaft head reaches the set tempering interval, the PLC control module 94 will send an opening control command to the solenoid valves of the furnace door lifting mechanism 6 cylinder 66 at the front and rear ends of the furnace body 1. The telescopic rod of the cylinder 66 will begin to retract, driving the chain 67 to pull towards the middle position of the furnace body 1. The meshing rotation of chain 67 and sprocket 65 raises the furnace doors 68 at the front and rear ends of furnace body 1; at the same time, PLC control module 94 sends a start control signal to servo motor 31 of chain conveyor 3, and chain conveyor 3 runs at a constant speed; when the drive shaft head after tempering moves to the position of proximity switch 8 at the rear end of furnace body 1, proximity switch 8 detects the position signal of drive shaft head and sends it to PLC control module 94, PLC control module 94 sends a start control signal to axial flow fan 71 of cooling mechanism 7, and two axial flow fans 71 simultaneously blow cooling air radially to the surface of drive shaft head for rapid cooling.

[0082] Various modifications to the above embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be adapted to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A constant-rate tempering furnace production line, comprising a furnace body, safety railings, and a chain conveyor; the furnace body is a hollow, enclosed square shape; two safety railings are respectively fixedly installed at the front and rear ends of the furnace body; characterized in that: The chain conveyor is fixedly installed at both ends of the furnace body, with the chain plates inside the furnace body. The chain conveyor is used to convey the drive shaft head at a constant speed. The heating mechanism is located on the upper left and right sides of the furnace body, providing the heat required for tempering. The hot air mixing mechanism is fixedly installed in the middle of the upper part of the furnace body, uniformly mixing the heat generated by the heating mechanism. Two furnace door lifting mechanisms are provided, one fixedly installed at the upper front end of the furnace body, and the other at the upper rear end. These mechanisms allow the furnace body to be closed or opened by raising and lowering the furnace door. The cooling mechanism is fixedly installed at the upper rear end of the chain conveyor, rapidly cooling the tempering drive shaft head. Two proximity switches are provided, one fixedly installed on the right rear side of the front safety fence of the furnace body, and the other on the right front side of the rear safety fence of the furnace body. The proximity switch sensors are aligned with the chain conveyor. The control system is fixedly installed at the bottom left side of the front end of the furnace body, coordinating the constant speed operation of the chain conveyor and the internal temperature control of the furnace body.

2. The constant-rate tempering furnace production line according to claim 1, characterized in that: The furnace body includes a furnace shell, and a furnace lining is built on the inner wall of the furnace shell. The furnace lining is made of a mixture of refractory fiber and lightweight insulating bricks. The heat-concentrating plate is fixedly installed on the inner wall of the furnace lining by a fixing keel. The heat-concentrating plate is a smooth stainless steel plate.

3. The constant-rate tempering furnace production line according to claim 1, characterized in that: The safety fence includes a fence frame, which is a hollow square body welded from square steel. The fence panel is fixedly installed on the outer side of the fence frame, and the surface of the fence panel has uniformly spaced convection heat exchange holes.

4. The constant-rate tempering furnace production line according to claim 1, characterized in that: The chain conveyor includes a driver, which is fixedly installed on the left side of the front safety fence frame of the furnace shell, near the upper part. The driver passes through the fence plate, and its power output shaft is fixedly connected to the drive shaft. Bearings are fixedly installed at both ends of the drive shaft, which is then fixedly installed on the upper lateral inner side of the front fence frame of the furnace shell via the bearings at both ends. Drive sprockets are symmetrically fixedly installed on the drive shaft, and the left end of the drive shaft passes through the outer side of the bearing seat and is fixedly connected to the power output shaft of the driver. Bearings are fixedly installed at both ends of the driven shaft, which is then fixedly installed on the upper lateral inner side of the rear fence frame of the furnace shell via the bearings at both ends. Driven sprockets are symmetrically installed on the driven shaft. A conveyor chain is meshed between the drive sprocket and the driven sprocket, and chain plates are evenly and equally spaced fixedly installed on the conveyor chain. The conveyor chain passes through the furnace openings at the front and rear ends of the furnace body. Each chain plate includes a chain plate body, which is a flat plate. A convex plate is vertically fixedly installed in the middle of the chain plate body, and honeycomb holes are evenly opened on both sides of the chain plate body.

5. The constant-rate tempering furnace production line according to claim 1, characterized in that: The heating mechanism includes a protective cover, which is U-shaped and has heat dissipation holes on the left and right sides. The protective cover is fixedly installed on the upper left and right edges of the furnace shell. The heating tube is installed at the corresponding position on the protective cover. The heating tube passes through the furnace shell, furnace lining and heat-concentrating plate and extends into the interior of the furnace body. The wiring terminal of the heating tube is located at the lower part of the protective cover. The thermocouple is installed in the middle of the upper part of the furnace shell. There are two thermocouples symmetrically arranged front and back. The thermocouple passes through the furnace shell, furnace lining and heat-concentrating plate and extends into the interior of the furnace body.

6. The constant-rate tempering furnace production line according to claim 1, characterized in that: The heat mixing mechanism includes a first fan motor and a second fan motor. The first fan motor and the second fan motor are fixedly installed in the upper middle position of the furnace shell by a motor bracket. The first fan motor and the second fan motor are arranged symmetrically front and back. The power output shafts of the first fan motor and the second fan motor extend into the interior of the furnace body. Impellers are fixedly installed on the bottom power output shafts of the first fan motor and the second fan motor. The first fan motor and the second fan motor are fixedly connected to the PLC control module through signal lines. The first fan motor and the second fan motor are fixedly connected to the internal power supply of the control cabinet through cables.

7. The constant-rate tempering furnace production line according to claim 1, characterized in that: The furnace door lifting mechanism includes a fixed frame, with two sets of fixed frames arranged symmetrically on the left and right. One set is fixedly located at the upper front end of the furnace shell, and the other set is fixedly located at the upper rear end of the furnace shell. Shaft seats are fixedly installed at both ends of the sprocket shaft, and the shaft seats are fixedly located inside the two symmetrically arranged fixed frames. The sprockets are symmetrically arranged on the sprocket shaft. Four cylinders are provided, arranged symmetrically on the left and right as a group. One set is located near the front end of the furnace shell, and the other set is fixedly located near the rear end of the furnace shell. The distance between the two symmetrically arranged cylinders is equal to the distance between the symmetrically arranged sprockets. Four chains are provided, one end of which is fixedly connected to the upper part of the furnace door, and the other end of which passes around the sprocket and is fixedly connected to the outer end of the cylinder's telescopic rod. The chains and sprockets are in meshing contact. The furnace door is larger than... The furnace opening dimensions are as follows: the furnace door fits snugly against the outer wall of the furnace shell, and is located directly above the furnace opening; the telescopic rods of a group of cylinders located near the front end of the upper part of the furnace shell face forward, and the telescopic rods of a group of cylinders located near the rear end of the upper part of the furnace shell face backward; the four cylinders are fixedly connected to the PLC control module via signal lines, and the four cylinders are fixedly connected to the air source solenoid valve via air pipes; the cooling mechanism includes an axial flow fan and a fan frame, the fan frame being a bent U-shaped plate, the fan frame being horizontally fixedly mounted on the rear fence frame of the furnace body, and the axial flow fan being symmetrically fixedly mounted on the fan frame; the axial flow fan is fixedly connected to the PLC control module via signal lines, and the axial flow fan is fixedly connected to the internal power supply of the control cabinet of the control system via a cable; the proximity switch is fixedly mounted on the upper right inner side of the fence frame via a Z-shaped bent plate; the proximity switch is fixedly connected to the PLC control module via signal lines.

8. The constant-rate tempering furnace production line according to claim 1, characterized in that: The control system includes a control cabinet, which is fixedly installed at the bottom left of the front of the furnace body. The display screen is located at the upper middle of the front side of the control cabinet. The temperature controller is fixedly installed at the lower left of the display screen. The PLC control module is located inside the control cabinet behind the display screen. The AC contactor is fixedly installed at the right side of the temperature controller. The display screen and the temperature controller are fixedly connected to the PLC control module via signal lines.

9. A control method for a constant-rate tempering furnace production line, characterized in that: Step 1: Setting Tempering Process Parameters: According to the tempering process requirements for the drive shaft head, set the tempering temperature (target temperature) inside the furnace through the control system's display screen, and simultaneously set the running speed (conveyor speed) of the chain conveyor drive; also set the tempering time for the drive shaft head according to the tempering process requirements. Step 2: Coordinated Control of Chain Conveyor Speed ​​and Furnace Internal Temperature: After setting the furnace tempering temperature and chain conveyor speed in Step 1, the robotic arm places the quenched drive shaft head onto the chain conveyor in one go. After the robotic arm moves away from the proximity switch at the front of the furnace, this... When the proximity switch senses the drive shaft head, it sends a position signal to the PLC control module. Simultaneously, the PLC control module sends lifting control signals to the furnace door lifting mechanisms at the front and rear ends of the furnace body. Upon receiving the signal, the solenoid valve of the furnace door lifting mechanism cylinder opens, and the cylinder begins to retract, pulling the chain towards the center of the furnace body. Through the rotational meshing of the chain and sprocket, the furnace door is pulled upwards along the front or rear side wall of the furnace body, thus opening the furnace door. At this time, the front and rear furnace doors open simultaneously. When the cylinder's retraction stroke reaches the maximum stroke of the magnetic switch within the cylinder, the magnetic switch sends a control signal to the PLC control module. Upon receiving the limit signal from the cylinder's retraction action, the PLC control module sends a start control signal to the chain conveyor's driver. The chain conveyor begins constant-speed operation and sends a close control signal to the solenoid valve supplying air to the cylinder. Simultaneously, the PLC control module sends start control signals to the first and second fan motors of the heat mixing mechanism, utilizing the high-speed rotation of the impellers at the bottom of the first and second fan motors to mix the heat inside the furnace. Meanwhile, the robotic arm continues to place the quenched drive shaft end on the chain according to the chain conveyor's operating rhythm. For each cycle of the chain conveyor, the robotic arm... The processed drive shaft head is placed on the chain plate at once; based on the running speed of the chain plate conveyor and the time required for the chain plate conveyor to reach the rear end of the furnace body, the PLC control module sends a stop control signal to the driver of the chain plate conveyor. The chain plate conveyor stops running and simultaneously sends an opening control signal to the solenoid valves supplying air to the cylinders of the furnace door lifting mechanism at the front and rear ends of the furnace body. The extension rod of the cylinder begins to extend. At this time, due to the weight of the furnace door itself, the furnace door slowly falls down and contacts the top of the convex plate of the chain plate through the meshing action of the chain and sprocket. At this time, the furnace door lifting mechanism at the front and rear ends of the furnace body closes at the same time.Meanwhile, the PLC control module feeds back the furnace internal temperature value detected in real time by the thermocouple through the temperature controller. The temperature controller's built-in PID control algorithm, in conjunction with the PLC control module, calculates and compares the temperature with the set tempering temperature. When the furnace internal tempering temperature is lower than the set tempering temperature, the PLC control module, in conjunction with the temperature controller, sends a control signal to the power controller to increase the heating tube power. When the furnace internal tempering temperature is higher than the set tempering temperature, the PLC control module, in conjunction with the temperature controller, sends a control signal to the power controller to decrease the heating tube power, ensuring that the furnace internal temperature always matches the set tempering temperature. Step 3: Tempering and cooling of the drive shaft head: After the constant speed operation of the chain conveyor in Step 2 and the constant temperature operation of the furnace internal temperature are completed, the furnace internal temperature will match the set tempering temperature. At this point, the PLC control module begins recording the tempering time of the drive shaft head. Once the tempering time reaches the set time, the PLC control module sends an opening control command to the solenoid valves of the furnace door lifting mechanism cylinders at the front and rear ends of the furnace body. The cylinder's telescopic rod retracts, pulling the chain towards the center of the furnace body. The chain, through its meshing with the sprocket, rotates and raises the furnace doors at the front and rear ends. Simultaneously, the PLC control module sends a start control signal to the chain conveyor driver, and the chain conveyor runs at a constant speed. When the tempered drive shaft head moves to the proximity switch position at the rear end of the furnace body, the proximity switch detects the position signal of the drive shaft head and sends it to the PLC control module. The PLC control module then sends a start control signal to the axial flow fans of the cooling mechanism. Both axial flow fans simultaneously blow cooling air onto the surface of the drive shaft head for rapid cooling.

10. The control method for a constant-rate tempering furnace production line according to claim 9, characterized in that: In step two, the width of the chain plate is the distance the chain plate travels in one cycle. In step two, the constant-speed operation control method of the chain conveyor is as follows: The PLC control module calculates the instantaneous operating speed of the chain conveyor in real time based on the preset operating speed of the chain conveyor and the distance between the proximity switches at the front and rear of the furnace body. By comparing the preset operating speed with the instantaneous operating speed, the PLC control module sends a dynamic frequency modulation signal to the frequency converter to dynamically adjust the speed of the chain conveyor driver, so that the chain conveyor always operates at a constant speed. In step two, during the coordinated temperature control process inside the furnace body, an AC contactor is installed on the main circuit of the heating tube. During normal operation, the heating circuit of the heating tube is controlled by a thyristor. Once a phase of the thyristor is broken down, the temperature controller alarms and the temperature controller immediately switches to the redundant temperature control system.

Images