Rubber open mill permanent magnet synchronous direct drive transmission system and control method

Abstract

The present application relates to rubber processing equipment technical field, specifically to a kind of rubber open mill permanent magnet synchronous direct drive transmission system and control method;Including rack, roller, permanent magnet synchronous direct drive motor, motor fine adjustment device, connecting device, transmission device, sealing mechanism and drive control system, motor direct drive main roll, through a pair of distribution gear realizes differential transmission of vice roll, driving gear adds integral boss to facilitate large torque gear coupling installation, main and vice roll sealing adaptation pitch adjustment dynamic sealing, motor bottom fine adjustment device can accurately adjust motor coaxial degree;While supporting system integration soft start, roller speed ratio stability, double roll load balancing, temperature protection and motor efficiency energy efficiency optimization;The present application cancels multistage reduction gearbox transmission structure, improves transmission efficiency and reduces energy consumption, oil leakage, vibration problem is improved, while solving direct drive reconstruction multiple structural sealing installation problem, adapts to rubber mixing heavy load fluctuation, frequent pitch adjustment working condition, realizes the efficient and accurate intelligent driving of equipment.

Description

Technical Field

[0001] This invention relates to the field of rubber processing equipment technology, specifically to a permanent magnet synchronous direct drive transmission system and control method for a rubber open mill. Background Technology

[0002] The open mill is one of the most basic pieces of equipment in the rubber industry, and it is widely used in the plasticizing, mixing, hot refining and sheeting processes of rubber products. The open mill is mainly composed of rollers, frame, adjusting device and transmission device. The material is pulled into the gap between two counter-rotating rollers at different linear velocities under the action of friction. The rubber compound is subjected to strong shearing and extrusion through the gap between the rollers, which raises the temperature of the material and increases its plasticity, thereby achieving the purpose of rubber refining.

[0003] Traditional open mill drive systems generally employ a three-phase asynchronous motor driving a multi-stage gearbox, where the motor outputs torque, which is then amplified by the gearbox and converted into a dual-output shaft configuration. This transmission method typically results in high energy consumption of the output motor, frequent maintenance, and the gearbox requires regular upkeep and maintenance. Furthermore, it suffers from poor reliability, severe wear and heat generation in the multi-stage transmission gears, and difficult and time-consuming repairs. Moreover, existing direct-drive solutions mostly focus only on the motor itself, lacking systematic control strategies tailored to the specific operating conditions of the open mill, thus hindering the full performance of the direct-drive system. Therefore, there is an urgent need for a permanent magnet synchronous direct-drive drive system and control method for rubber open mills that can solve the aforementioned technical challenges while achieving efficient and reliable open mill drive control. Summary of the Invention

[0004] The purpose of this invention is to solve the problems in the background art and provide a permanent magnet synchronous direct drive transmission system and control method for a rubber open mill, so as to achieve efficient and reliable open mill drive control.

[0005] The above-mentioned technical objective of the present invention is achieved through the following technical solution: A permanent magnet synchronous direct drive transmission system for a rubber open mill includes a frame, rollers, a direct drive motor, a motor fine-tuning device, a connecting device, a transmission device, a transmission sealing mechanism, and a motor drive control system. The rollers include a main roller and an auxiliary roller arranged parallel to each other on the frame. The axial position of the main roller is fixed, and the auxiliary roller can move radially relative to the main roller to adjust the center distance between them. The motor fine-tuning device is located at the bottom of the direct drive motor and is used to fine-tune the distance of the direct drive motor to ensure the coaxiality between the output shaft of the direct drive motor and the main roller. The transmission device is provided with a pair of speed ratio gear pairs, including a driving gear and a driven gear that mesh with each other. The driving gear and the driven gear are coaxially fixedly connected to the main roller and the auxiliary roller, respectively. The output shaft of the direct drive motor is coaxially connected to the driving gear through a connecting device. The transmission sealing mechanism includes a main roller seal, a secondary roller seal, and a motor shaft seal. The main roller seal is located at the main through-shaft hole of the transmission device, the secondary roller seal is located at the secondary through-shaft hole of the transmission device, and the motor shaft seal is located at the motor through-shaft hole of the transmission device. The motor drive control system is electrically connected to the direct drive motor and is used to control the operating status of the direct drive motor.

[0006] Preferably, the connecting device includes a first coupling and a second coupling that are coaxially and fixedly connected to each other. The first coupling is fixedly connected to the output shaft of the direct drive motor, and the second coupling is fixedly connected to the drive gear. The drive gear has a boss with a thickness of 70-90mm on its end face facing the second coupling. The boss end face has a threaded hole for installing the second coupling and a first keyway. The end of the second coupling connected to the boss has a through hole corresponding to the threaded hole and a second keyway corresponding to the first keyway. A flat key is also provided in the first keyway and the second keyway.

[0007] Preferably, the main roller seal and the motor shaft seal have the same structure, including a first sealing plate formed by splicing two semi-circular ring plates. A felt strip groove is opened on the inner circumference of the first sealing plate, and a sealing felt strip is embedded in the groove. The diameter of the main through-shaft hole is larger than the shaft diameter of the main roller. During installation, it is not necessary to ensure that the main roller and the main through-shaft hole are concentric. The first sealing plate is installed on the outside of the main through-shaft hole, and its position can be adjusted according to the actual position of the main roller shaft.

[0008] Preferably, the auxiliary roller seal includes a second sealing plate, the second sealing plate having a central hole adapted to the shaft of the auxiliary roller, the second sealing plate being fixedly sleeved on the auxiliary roller and laterally locked by bolts in a plurality of circumferentially distributed tightening holes on the side of the central hole; an annular felt groove is formed on the end face of the second sealing plate facing the auxiliary through-shaft hole, an annular sealing felt is embedded in the groove, and the radial coverage of the annular felt groove is greater than the maximum radial displacement of the auxiliary roller in the auxiliary through-shaft hole.

[0009] Preferably, the motor fine-tuning device includes two sets of mounting base plates and several set screw blocks fixed to the mounting base plates. The mounting base plates are fixed to the frame by bolts, and the direct drive motor is fixed to the mounting base plates by bolts. The set screw blocks are internally threaded with adjusting screws that abut against the end face of the direct drive motor's base. The horizontal position of the direct drive motor is fine-tuned by turning the adjusting screws. A height adjusting shim is also provided between the mounting base plates and the bottom surface of the direct drive motor's base for fine-tuning the height position of the direct drive motor.

[0010] Preferably, the motor drive control system includes a frequency converter, a main controller, a speed sensor, a torque sensor, a temperature sensor, and a human-machine interface. The frequency converter is electrically connected to the direct-drive motor and is used to convert industrial frequency AC power into AC power with adjustable frequency and voltage to drive the direct-drive motor. The speed sensors are respectively installed on the main roller and the auxiliary roller and are used to detect the rotational speed of the rollers in real time. The torque sensor is installed on the output shaft of the direct-drive motor and is used to detect the output torque in real time. Multiple temperature sensors are provided and are used to detect the winding temperature of the direct-drive motor, the surface temperature of the main roller and the auxiliary roller, and the ambient temperature. The main controller is electrically connected to the frequency converter, the speed sensor, the torque sensor, and the temperature sensor. The human-machine interface is electrically connected to the main controller and is used to set process parameters and display the operating status.

[0011] A control method for a permanent magnet synchronous direct drive rubber mill includes the following steps: S1. Initialization Control: Receives the rubber mixing process parameters input from the human-machine interface, including the target main roller speed n1_set, the target auxiliary roller speed n2_set, the rubber mixing time t_set, and the upper temperature limit T_max. Calculates the target speed ratio i_set=n2_set / n1_set based on n1_set and n2_set, and verifies whether i_set is consistent with the fixed tooth ratio of the driving gear and the driven gear. If they are inconsistent, an alarm is issued. S2, Soft Start Control: Controls the frequency converter to increase the output frequency of the direct drive motor according to the preset soft start curve. The soft start time is set to 10-30s, and the starting current is limited to within 1.5 times the rated current. During the soft start process, the output torque is monitored in real time. If the output torque exceeds the preset starting torque threshold, the soft start time is extended or the starting speed is reduced. S3. Steady-speed operation control: After the direct-drive motor reaches the target rotation speed, it enters the steady-speed operation phase. The main controller calculates the actual speed ratio i_real = n2_real / n1_real based on the actual main roller rotation speed n1_real and the actual auxiliary roller rotation speed n2_real fed back by the rotation speed sensor. If the deviation between i_real and i_set exceeds ±1%, the output rotation speed of the direct-drive motor is finely adjusted through the frequency converter to ensure the speed ratio of the two rollers is stable; S4. Temperature protection control: The main controller receives data from each temperature sensor in real time. When the temperature of the motor winding exceeds the first temperature threshold T1, the motor cooling fan is started or the motor output current is reduced. When the temperature of the motor winding exceeds the second temperature threshold T2, the motor rotation speed is automatically reduced. When the temperature of the motor winding exceeds the third temperature threshold T3, the motor is controlled to stop for protection, where T1<T2<T3. When the surface temperature of the rollers exceeds T_max, an alarm is issued to prompt the operator to adjust the roller temperature; S5. Shutdown control: After receiving a shutdown instruction, the main controller controls the frequency converter to reduce the motor rotation speed according to a preset deceleration curve, with the deceleration time set to 5-15s. When the motor rotation speed drops to a preset low speed threshold, braking is activated to stop the roller shaft from rotating; after the shutdown is completed, the energy consumption data, fault information, maintenance prompts and the like of this operation are recorded and uploaded to the human-machine interaction interface for display.

[0012] As a preference, in the steady-speed operation control of step S3, the main controller also performs load balancing control. The main controller compares the actual output torque T_real fed back by the torque sensor with a preset load torque curve. If T_real continues to be higher than the corresponding value of the load torque curve for more than a preset time, it is determined that the rubber material is overloaded, and the output torque is automatically reduced or an alarm is issued.

[0013] As a preference, the torque sensor further includes a main-path torque sensor and an auxiliary-path torque sensor respectively arranged on the main roller transmission path and the auxiliary roller transmission path. The main controller compares the main-path torque T_main and the auxiliary-path torque T_sub in real time. If |T_main-T_sub| / T_avg>10%, where T_avg=(T_main+T_sub) / 2, it is determined that the loads of the two rollers are unbalanced. By adjusting the output frequency of the motor, the loads of the two rollers are automatically redistributed using the friction characteristics between the rubber material and the rollers until the torque difference between the two paths is within the allowable range.

[0014] Preferably, the main controller is also configured to perform energy efficiency optimization control. During the steady-speed operation phase, the main controller calculates the actual output power P_real = T_real × n_real / 9550 at the current operating point based on the real-time monitored actual output torque T_real and actual speed n_real. Combined with the efficiency diagram of the direct drive motor, it determines whether the current operating point is in the high-efficiency zone. If the current operating point deviates from the high-efficiency zone by more than a threshold, the operating point is guided to the high-efficiency zone by fine-tuning the target speed or prompting the operator to adjust the roller gap, so as to achieve the optimization of system energy efficiency.

[0015] In summary, the beneficial effects of this invention are as follows: 1. The present invention discloses a permanent magnet synchronous direct drive transmission system and control method for a rubber open mill. It adopts a three-phase permanent magnet synchronous multi-stage motor for direct drive, replacing the traditional drive mode of asynchronous motor plus multi-stage gearbox. The system transmission efficiency is effectively improved. At the same time, the multi-stage gearbox is eliminated, and only one pair of necessary speed ratio distribution gears are retained, which greatly reduces the failure points in the transmission environment. It also eliminates the need for frequent gear oil changes, completely eliminates the risk of oil leakage, reduces maintenance costs, eliminates the mechanical loss of multi-stage gear transmission, and reduces working energy consumption. 2. The permanent magnet synchronous direct drive transmission system and control method for a rubber open mill described in this invention have a compact transmission system structure, reducing the overall volume of the permanent magnet synchronous direct drive motor and the distribution gearbox, thus significantly reducing the equipment's footprint. Simultaneously, a boss structure is designed on the end face of the main gear inside the distribution gearbox, and a coupling is directly installed on the boss. This solves the problem of insufficient coupling connection space and poor connection stability caused by excessively thick distribution gears in the application of high-torque direct drive motors, ensuring the overall strength of the gears and the reliability of the transmission. 3. The permanent magnet synchronous direct drive transmission system and control method for a rubber open mill described in this invention enlarges the main through-shaft hole on the distribution gearbox. During installation, it is not necessary to deliberately ensure the concentricity of the hole and the roller shaft. After installation, the roller is sealed, which greatly reduces the installation accuracy and facilitates subsequent disassembly and maintenance. At the same time, a sealing structure that moves with the roller is designed on the auxiliary roller, realizing full-stroke dynamic sealing during the adjustment process of the auxiliary roller, and completely solving the sealing problem of the adjustment auxiliary roller. 4. The permanent magnet synchronous direct drive transmission system and control method for a rubber open mill described in this invention adopts a collaborative control method designed for the special working conditions of the open mill, including soft start control, speed ratio stabilization control, load balancing control, temperature monitoring and protection control, and energy efficiency optimization control. This fully leverages the performance advantages of the permanent magnet direct drive transmission system and realizes intelligent, precise, and efficient rubber mixing process. Attached Figure Description

[0016] Figure 1This is a schematic diagram of the permanent magnet synchronous direct drive transmission system for a rubber open mill according to the present invention; Figure 2 This is a schematic diagram of the transmission device of the present invention; Figure 3 This is a schematic diagram of the connecting device of the present invention; Figure 4 This is a schematic diagram of the structure of the drive gear of the present invention; Figure 5 This is a schematic diagram of the structure of the second coupling of the present invention; Figure 6 This is a schematic diagram of the main roller seal of the present invention; Figure 7 This is a schematic diagram of the structure of the semi-circular ring plate of the present invention; Figure 8 This is a schematic diagram of the structure of the auxiliary roller seal of the present invention; Figure 9 This is a schematic diagram of the structure of the second sealing plate of the present invention; Figure 10 This is a schematic diagram of the motor fine-tuning device of the present invention; Figure 11 This is a schematic diagram of the height adjustment shim of the present invention; Figure 12 This is a schematic block diagram of the motor drive control system of the present invention; Figure 13 This is a flowchart of the control method of the present invention.

[0017] Markings in the diagram: 1. Frame; 2. Roller; 21. Main roller; 22. Auxiliary roller; 3. Direct drive motor; 4. Motor fine-tuning device; 41. Mounting base plate; 42. Set screw block; 43. Adjusting screw; 44. Height adjustment shim; 5. Connecting device; 51. First coupling; 52. Second coupling; 521. Through hole; 522. Second keyway; 6. Transmission device; 61. Drive gear; 611. Boss; 612. Threaded hole; 613. First keyway; 614. Flat key; 62. Driven gear; 63. Main through-shaft hole; 64. Auxiliary through-shaft hole; 65. Motor through-shaft hole; 7. Transmission sealing mechanism; 71. Main roller seal; 711. Semi-circular ring plate; 712. 713. First sealing plate; 72. Felt strip groove; 73. Secondary roller seal; 74. Second sealing plate; 75. Center hole; 76. Tightening wire hole; 77. Annular felt groove; 77. Motor shaft seal; 88. Motor drive control system; 89. Frequency converter; 80. Main controller; 81. Speed ​​sensor; 82. Main roller speed sensor; 83. Secondary roller speed sensor; 84. Torque sensor; 85. Output torque sensor; 86. Main torque sensor; 87. Secondary torque sensor; 88. Temperature sensor; 89. Motor temperature sensor; 80. Roller temperature sensor; 81. Ambient temperature sensor; 82. Human-machine interface. Detailed Implementation

[0018] The following specific embodiments are merely illustrative of the present invention and are not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to these embodiments without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of the present invention.

[0019] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0020] Example

[0021] according to Figure 1 , Figure 2 As shown, a permanent magnet synchronous direct drive transmission system for a rubber open mill includes a frame 1, a roller 2, a direct drive motor 3, a motor fine-tuning device 4, a connecting device 5, a transmission device 6, a transmission sealing mechanism 7, and a motor drive control system 8. The roller 2 includes a main roller 21 and an auxiliary roller 22 arranged parallel to each other on the frame 1. The axial position of the main roller 21 is fixed, and the auxiliary roller 22 can move radially relative to the main roller 21 to adjust the center distance between the two. The motor fine-tuning device 4 is located at the bottom of the direct drive motor 3 and is used to fine-tune the distance of the direct drive motor 3 to ensure the coaxiality between the output shaft of the direct drive motor 3 and the main roller 21. The transmission device 6 is equipped with a pair of speed ratio gear pairs, including a driving gear 61 and a driven gear 62 that mesh with each other. The driving gear 61 and the driven gear 62 are coaxially fixedly connected to the main roller 21 and the auxiliary roller 22, respectively. The output shaft of the direct drive motor 3 is coaxially connected to the driving gear 61 through the connecting device 5. The transmission sealing mechanism 7 includes a main roller seal 71, a secondary roller seal 72, and a motor shaft seal 73. The main roller seal 71 is located at the main through-shaft hole 63 of the transmission device 6, the secondary roller seal 72 is located at the secondary through-shaft hole 64 of the transmission device 6, and the motor shaft seal 73 is located at the motor through-shaft hole 65 of the transmission device 6. The motor drive control system 8 is electrically connected to the direct drive motor 3 and is used to control the operating status of the direct drive motor 3.

[0022] according to Figures 3-5 As shown, the connecting device 5 includes a first coupling 51 and a second coupling 52 that are coaxially and fixedly connected to each other. The first coupling 51 is fixedly connected to the output shaft of the direct drive motor 3, and the second coupling 52 is fixedly connected to the drive gear 61. The drive gear 61 has a boss 611 with a thickness of 80mm on its end face facing the second coupling 52. The end face of the boss 611 has a threaded hole 612 for installing the second coupling 52 and a first keyway 613. The end of the second coupling 52 connected to the boss 611 has a through hole 521 corresponding to the threaded hole 612 and a second keyway 522 corresponding to the first keyway 613. A flat key 614 is also provided in the first keyway 613 and the second keyway 522.

[0023] The first coupling 51 and the second coupling 52 are fixedly connected by a pin. The first coupling 51 is fixedly connected to the output shaft of the direct drive motor 3 by a spline or a tightening sleeve. The second coupling 52 is fixedly connected to the drive gear 61. Since the drive gear 61 needs to transmit large torque and has a thick tooth width, a boss 611 is provided on the end face facing the second coupling 52. The boss 611 is integrally formed with the drive gear 61, and the boss 611 is provided with a threaded hole 612 and a first key. During installation, the mounting surface of the second coupling 52 corresponds to the boss 611. The flat key 614 is embedded in the first keyway 613 and the second keyway 522. Then, high-strength bolts are passed through the through hole 521 and the threaded hole 612 to lock and fix the second coupling 52 onto the boss 611. The torque is transmitted by the preload of the bolts and the flat key 614. The boss 611 ensures the overall strength of the transmission and provides sufficient installation space and connection reliability for the second coupling 52.

[0024] according to Figures 6-9As shown, the main roller seal 71 and the motor shaft seal 73 have the same structure, including a first sealing plate 712 formed by splicing two semi-circular ring plates 711. A felt strip groove 713 is opened on the inner circumference of the first sealing plate 712, and a sealing felt strip is embedded in the groove. The diameter of the main through-shaft hole 63 is larger than the shaft diameter of the main roller 21. During installation, it is not necessary to ensure that the main roller 21 and the main through-shaft hole 63 are concentric. The first sealing plate 712 is installed on the outside of the main through-shaft hole 63, and its position can be adjusted according to the actual position of the main roller 21 shaft. The auxiliary roller seal 72 includes a second sealing plate. The second sealing plate 721 has a central hole 722 that matches the shaft of the auxiliary roller 22. The second sealing plate 721 is fixedly sleeved on the auxiliary roller 22 and is laterally locked by bolts in a plurality of circumferentially distributed tightening holes 723 on the side of the central hole 722. An annular felt groove 724 is provided on the end face of the second sealing plate 721 facing the auxiliary shaft hole 64. An annular sealing felt is embedded in the groove, and the radial coverage of the annular felt groove 724 is greater than the maximum radial displacement of the auxiliary roller 22 in the auxiliary shaft hole 64.

[0025] The main through-shaft hole 63 has a diameter 10-20mm larger than the shaft diameter of the main roller 21. This eliminates the need to ensure concentricity between the main through-shaft hole 63 and the main roller 21 during installation, reducing the requirements for machining and installation precision. Two semi-circular ring plates 711, designed in half, are joined to form the first sealing plate 712. After positioning, the first sealing plate 712 can be directly locked onto the distribution gearbox, facilitating installation and disassembly. The auxiliary roller 22, requiring adjustment relative to the main roller 21, needs to ensure a tight seal during adjustment. Therefore, the second sealing plate 721 is fixed to the shaft of the auxiliary roller 22 by heat fitting process, and locked to the shaft by multiple tightening holes 723. At the same time, the radial coverage of the annular felt groove 724 on the second sealing plate 721 is greater than the maximum radial displacement of the auxiliary roller 22 in the auxiliary shaft hole 64, so that the auxiliary roller 22 can achieve full-stroke dynamic sealing at any position of the maximum and minimum adjustment distance. The second sealing plate 721 moves with the auxiliary roller 22, which completely solves the problem of dynamic sealing during the adjustment process.

[0026] according to Figure 10 , Figure 11 As shown, the motor fine-tuning device 4 includes two sets of mounting base plates 41 and several set screw blocks 42 fixed on the mounting base plates 41. The mounting base plates 41 are fixed to the frame 1 by bolts. The direct drive motor 3 is fixed to the mounting base plates 41 by bolts. The set screw blocks 42 are internally threaded with adjusting screws 43 that abut against the end face of the base of the direct drive motor 3. The horizontal position of the direct drive motor 3 is fine-tuned by turning the adjusting screws 43. A height adjusting shim 44 is also provided between the mounting base plates 41 and the bottom surface of the base of the direct drive motor 3 for fine-tuning the height position of the direct drive motor 3.

[0027] The motor fine-tuning device 4 has two sets of mounting base plates 41 located at the bottom of the direct drive motor 3's base. These plates are used to fine-tune the horizontal and vertical positions of the direct drive motor 3. The mounting base plates 41 are fixed to the frame 1 with bolts, and the base of the direct drive motor 3 is locked to the mounting base plates 41 with bolts. Adjusting screws 43 are internally threaded onto the set screw blocks 42 in different directions on the mounting base plates 41. By turning the adjusting screws 43 in different directions, the horizontal position of the direct drive motor 3 can be fine-tuned. By replacing the height adjusting shims 44 of different heights, the height position of the direct drive motor 3 can be fine-tuned, making the adjustment of the direct drive motor 3 during installation and alignment more convenient.

[0028] according to Figure 12 As shown, the motor drive control system 8 includes a frequency converter 81, a main controller 82, a speed sensor 83, a torque sensor 84, a temperature sensor 85, and a human-machine interface 86. The frequency converter 81 is electrically connected to the direct drive motor 3 and is used to convert the industrial frequency AC power into AC power with adjustable frequency and voltage to drive the direct drive motor 3. The speed sensor 83 is respectively installed on the main roller 21 and the auxiliary roller 22 and is used to detect the speed of the roller 2 in real time. The torque sensor 84 is installed on the output shaft of the direct drive motor 3 and is used to detect the output torque in real time. Multiple temperature sensors 85 are provided and are used to detect the winding temperature of the direct drive motor 3, the surface temperature of the main roller 21 and the auxiliary roller 22, and the ambient temperature. The main controller 82 is electrically connected to the frequency converter 81, the speed sensor 83, the torque sensor 84, and the temperature sensor 85. The human-machine interface 86 is electrically connected to the main controller 82 and is used to set process parameters and display the operating status.

[0029] The inverter 81 is electrically connected to the direct drive motor 3, employing vector control or direct torque control to convert the mains frequency AC power into AC power with adjustable frequency and voltage to drive the direct drive motor 3. The inverter 81's power is matched to the direct drive motor 3, and it has overload protection, overcurrent protection, overvoltage protection, and undervoltage protection functions. The speed sensor 83 includes a main roller speed sensor 831 located on the main roller 21 and an auxiliary roller speed sensor 832 located on the auxiliary roller 22. These can be encoders or rotary transformers, used to detect the real-time speeds n1_real and n2_real of the two rollers. The torque sensor 84 includes an output torque sensor 841 located on the output shaft of the direct drive motor 3, used to detect the real-time output torque T_real. It also includes sensors located on the main roller drive path and the auxiliary roller drive path. The main torque sensor 842 and the auxiliary torque sensor 843 on the roller drive path are used to detect T_main and T_sub in real time, respectively. The temperature sensor 85 includes a motor temperature sensor 851 installed at the stator winding of the direct drive motor 3, a roller temperature sensor 852 installed on the main roller 21 and the auxiliary roller 22, and an ambient temperature sensor 853. The main controller 82 adopts a PLC or industrial control computer and is electrically connected to the frequency converter 81, speed sensor 83, torque sensor 84 and temperature sensor 85, respectively. The main controller 82 has a built-in control algorithm optimized for open mill operating conditions. The human-machine interface 86 is electrically connected to the main controller 82 and adopts a touch screen for operators to set process parameters, display the operating status in real time and receive fault alarms.

[0030] according to Figure 13 As shown, this embodiment also provides a control method for permanent magnet synchronous direct drive of a rubber open mill, including the following steps: Step S1, Initialization Control: Before the open mill is started and the equipment is not running, the system executes the following initialization procedure: S11. System power-on self-test: After the main controller 82 is powered on, it sequentially checks the status of the frequency converter 81, the status of the direct drive motor 3, the communication status of each sensor, and the temperature status of each part. If any fault is detected, the fault code is displayed on the human-machine interface 86 and the start is locked. After the fault is cleared, the self-test is repeated. After all self-tests pass, the system enters the standby state and waits for the operator to input process parameters.

[0031] S12. Process Parameter Setting: The operator inputs the rubber mixing process parameters through the human-machine interface 86, including the target main roller speed n1_set, the target auxiliary roller speed n2_set, the rubber mixing time t_set, and the upper temperature limit T_max; the main controller 82 automatically calculates the target speed ratio i_set=n2_set / n1_set and verifies whether the target speed ratio is consistent with the fixed tooth ratio of the driving gear 61 and the driven gear 62 in the distribution gearbox; if they are inconsistent, it indicates that the process parameter setting is incorrect or the gear configuration is incorrect, and the main controller 82 displays a fault alarm on the human-machine interface 86; if they are consistent, proceed to the next step.

[0032] Step S2, Soft Start Control: The operator issues a start command through the human-machine interface 86. The main controller 82 controls the frequency converter 81 to increase the output frequency according to the preset soft start curve. The soft start time is set to 20s, and the starting current is limited to within 1.5 times the rated current. During the soft start process, the main controller 82 monitors the output torque T_real fed back by the output torque sensor 841 in real time. If T_real exceeds the preset starting torque threshold, the main controller 82 automatically extends the soft start time to 30s or reduces the starting acceleration to avoid motor overcurrent or mechanical shock.

[0033] Step S3, Steady-speed operation control: When the speed of the direct-drive motor 3 reaches the target value, it enters the steady-speed operation stage, and the main controller 82 executes the following cooperative control subroutine: S31. Speed ​​Ratio Stability Control: The main controller 82 calculates the actual speed ratio i_real = n2_real / n1_real based on the actual main roller speed n1_real and actual auxiliary roller speed n2_real fed back by the main roller speed sensor 831 and the auxiliary roller speed sensor 832. Since the gear ratio of the two gears is fixed, i_real should be equal to i_set under normal circumstances. However, due to factors such as gear wear and load fluctuations, the actual speed ratio may deviate. If |i_real-i_set| / i_set>1%, the main controller 82 finely adjusts the motor speed by finely adjusting the output power of the frequency converter 81 to compensate for the speed ratio deviation, ensure the speed ratio stability of the two rollers, and ensure the quality of rubber mixing.

[0034] S32, Output shaft load balancing control: The main controller 82 compares the actual output torque T_real fed back by the output torque sensor 841 with the preset load torque curve. If T_real is continuously higher than the corresponding value of the load torque curve for more than a preset time, it is determined that the rubber material is overloaded, and the output torque is automatically reduced or an alarm is issued.

[0035] S33. Roller load balancing control: The main controller 82 compares in real time the main path torque T_main detected by the main path torque sensor 842 and the auxiliary path torque T_sub detected by the auxiliary path torque sensor 843. If |T_main-T_sub| / T_avg>10%, where T_avg=(T_main+T_sub) / 2, it is determined that the loads of the two rollers are unbalanced, which may be caused by uneven distribution of the rubber material or difference in the surface state of the rollers. The main controller 82 finely adjusts the output power of the frequency converter 81, and automatically redistributes the loads of the two rollers by using the friction characteristics between the rubber material and the rollers, until the torque difference between the two paths is within the allowable range.

[0036] S34. Energy efficiency optimization control: The main controller 82 calculates the actual output power P_real=T_real×n_real / 9550 at the current operating point according to the actually monitored actual output torque T_real and actual rotational speed n_real. The main controller 82 has a built-in efficiency map of the direct drive motor 3, and judges whether the T_real and n_real of the current operating point are in the high-efficiency zone. If the current operating point deviates from the high-efficiency zone by more than a preset threshold, the main controller 82 gives an alarm prompt on the human-machine interaction interface 86. The operator can finely adjust the target rotational speed or adjust the roller gap according to the prompt, to guide the operating point to the vicinity of the high-efficiency zone, so as to realize the optimization of the system energy efficiency.

[0037] Step S4. Temperature protection control: The main controller 82 receives data from each temperature sensor 85 in real time. When the motor winding temperature detected by the motor temperature sensor 851 exceeds the first temperature threshold T1, the motor cooling fan is started or the motor output current is reduced. When the motor winding temperature exceeds the second temperature threshold T2, the motor speed is automatically reduced. When the motor winding temperature exceeds the third temperature threshold T3, the motor is controlled to stop for protection, where T1<T2<T3. When the roller surface temperature detected by the roller temperature sensor 852 exceeds T_max, an alarm is issued to prompt the operator to adjust the roller temperature.

[0038] Step S5. Shutdown control: When the rubber mixing time reaches t_set, or after the operator manually issues a stop command, the main controller 82 executes shutdown control. The main controller 82 controls the frequency converter 81 to reduce the motor speed according to a preset deceleration curve, with a deceleration time of 10s, and an S-shaped deceleration curve is adopted to avoid inertial impact of the rubber material. When the motor speed drops to a preset low speed threshold, braking is activated to make the main roller 21 and the auxiliary roller 22 stop rotating quickly within 1 / 4 revolution, meeting the requirements of safety specifications. After the shutdown is completed, the main controller 82 records the total energy consumption data, average rotational speed, average torque, maximum temperature, fault information and maintenance prompts of this operation, generates an operation report and uploads it to the human-machine interaction interface 86 for display. Meanwhile, the data can be stored in a local database or uploaded to a cloud system, which is convenient for production management and equipment maintenance decision-making.

Claims

1. A permanent magnet synchronous direct drive transmission system for a rubber open mill, characterized in that, It includes a frame (1), rollers (2), direct drive motor (3), motor fine-tuning device (4), connecting device (5), transmission device (6), transmission sealing mechanism (7), and motor drive control system (8). The roller (2) includes a main roller (21) and a secondary roller (22) arranged parallel to each other on the frame (1). The axial position of the main roller (21) is fixed, and the secondary roller (22) can move radially relative to the main roller (21) to adjust the center distance between the two. The motor fine-tuning device (4) is located at the bottom of the direct drive motor (3) and is used to fine-tune the distance of the direct drive motor (3) to ensure the coaxiality between the output shaft of the direct drive motor (3) and the main roller (21). The transmission device (6) is provided with a pair of speed ratio gear pairs, including a driving gear (61) and a driven gear (62) that mesh with each other. The driving gear (61) and the driven gear (62) are coaxially fixedly connected to the main roller (21) and the auxiliary roller (22) respectively. The output shaft of the direct drive motor (3) is coaxially connected to the driving gear (61) through the connecting device (5). The transmission sealing mechanism (7) includes a main roller seal (71), a secondary roller seal (72), and a motor shaft seal (73). The main roller seal (71) is located at the main through-shaft hole (63) of the transmission device (6), the secondary roller seal (72) is located at the secondary through-shaft hole (64) of the transmission device (6), and the motor shaft seal (73) is located at the motor through-shaft hole (65) of the transmission device (6). The motor drive control system (8) is electrically connected to the direct drive motor (3) and is used to control the operating status of the direct drive motor (3).

2. The permanent magnet synchronous direct drive transmission system for a rubber open mill according to claim 1, characterized in that, The connecting device (5) includes a first coupling (51) and a second coupling (52) that are coaxially and fixedly connected to each other. The first coupling (51) is fixedly connected to the output shaft of the direct drive motor (3), and the second coupling (52) is fixedly connected to the drive gear (61). The drive gear (61) has a boss (611) with a thickness of 70-90mm on the end face facing the second coupling (52). The end face of the boss (611) has a threaded hole (612) for installing the second coupling (52) and a first keyway (613). The end of the second coupling (52) connected to the boss (611) has a through hole (521) corresponding to the threaded hole (612) and a second keyway (522) corresponding to the first keyway (613). A flat key (614) is also provided in the first keyway (613) and the second keyway (522).

3. The permanent magnet synchronous direct drive transmission system for a rubber open mill according to claim 1, characterized in that, The main roller seal (71) and the motor shaft seal (73) have the same structure, including a first sealing plate (712) formed by splicing two semi-circular ring plates (711). The inner circumferential surface of the first sealing plate (712) is provided with a felt strip groove (713), and a sealing felt strip is embedded in the groove. The diameter of the main through-shaft hole (63) is larger than the shaft diameter of the main roller (21). During installation, it is not necessary to ensure that the main roller (21) and the main through-shaft hole (63) are concentric. The first sealing plate (712) is installed on the outside of the main through-shaft hole (63), and its position can be adjusted according to the actual position of the shaft of the main roller (21).

4. The permanent magnet synchronous direct drive transmission system for a rubber open mill according to claim 1, characterized in that, The auxiliary roller seal (72) includes a second sealing plate (721). The second sealing plate (721) has a central hole (722) that matches the shaft of the auxiliary roller (22). The second sealing plate (721) is fixedly sleeved on the auxiliary roller (22) and is laterally locked by bolts in a plurality of circumferentially distributed tightening holes (723) on the side of the central hole (722). The second sealing plate (721) has an annular felt groove (724) on one end face facing the auxiliary through-shaft hole (64). An annular sealing felt is embedded in the groove, and the radial coverage of the annular felt groove (724) is greater than the maximum radial displacement of the auxiliary roller (22) in the auxiliary through-shaft hole (64).

5. The permanent magnet synchronous direct drive transmission system for a rubber open mill according to claim 1, characterized in that, The motor fine-tuning device (4) includes two sets of mounting base plates (41) and several set screw blocks (42) fixed on the mounting base plates (41). The mounting base plates (41) are fixed to the frame (1) by bolts. The direct drive motor (3) is fixed to the mounting base plates (41) by bolts. The set screw blocks (42) are internally threaded with adjusting screws (43) that abut against the end face of the base of the direct drive motor (3). The horizontal position of the direct drive motor (3) is fine-tuned by turning the adjusting screws (43). A height adjustment shim (44) is also provided between the mounting base plates (41) and the bottom surface of the base of the direct drive motor (3) for fine-tuning the height position of the direct drive motor (3).

6. The permanent magnet synchronous direct drive transmission system for a rubber open mill according to claim 1, characterized in that, The motor drive control system (8) includes a frequency converter (81), a main controller (82), a speed sensor (83), a torque sensor (84), a temperature sensor (85), and a human-machine interface (86). The frequency converter (81) is electrically connected to the direct drive motor (3) and is used to convert the industrial frequency AC power into AC power with adjustable frequency and voltage to drive the direct drive motor (3). The speed sensor (83) is respectively installed on the main roller (21) and the auxiliary roller (22) to detect the rotational speed of the roller (2) in real time. The torque sensor (84) is installed on the main roller (21) and the auxiliary roller (22). The output shaft of the direct drive motor (3) is used to detect the output torque in real time; multiple temperature sensors (85) are provided, which are used to detect the winding temperature of the direct drive motor (3), the surface temperature of the main roller (21) and the auxiliary roller (22), and the ambient temperature; the main controller (82) is electrically connected to the frequency converter (81), the speed sensor (83), the torque sensor (84) and the temperature sensor (85), respectively; the human-machine interface (86) is electrically connected to the main controller (82) and is used to set process parameters and display the operating status.

7. A control method for a permanent magnet synchronous direct drive of a rubber open mill, comprising the permanent magnet synchronous direct drive transmission system for a rubber open mill as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Initialization Control: Receives the rubber mixing process parameters input from the human-machine interface, including the target main roller speed n1_set, the target auxiliary roller speed n2_set, the rubber mixing time t_set, and the upper temperature limit T_max. Calculates the target speed ratio i_set=n2_set / n1_set based on n1_set and n2_set, and verifies whether i_set is consistent with the fixed tooth ratio of the driving gear and the driven gear. If they are inconsistent, an alarm is issued. S2, Soft Start Control: Controls the frequency converter to increase the output frequency of the direct drive motor according to the preset soft start curve. The soft start time is set to 10-30s, and the starting current is limited to within 1.5 times the rated current. During the soft start process, the output torque is monitored in real time. If the output torque exceeds the preset starting torque threshold, the soft start time is extended or the starting speed is reduced. S3. Steady-speed operation control: After the direct drive motor reaches the target speed, it enters the steady-speed operation stage. The main controller calculates the actual speed ratio i_real=n2_real / n1_real based on the actual main roller speed n1_real and the actual auxiliary roller speed n2_real fed back by the speed sensor. If the deviation between i_real and i_set exceeds ±1%, the output speed of the direct drive motor is finely adjusted through the frequency converter to ensure the stability of the speed ratio between the two rollers. S4. Temperature protection control: The main controller receives data from each temperature sensor in real time. When the temperature of the motor winding exceeds the first temperature threshold T1, the motor cooling fan is started or the motor output current is reduced. When the temperature of the motor winding exceeds the second temperature threshold T2, the motor speed is automatically reduced. When the temperature of the motor winding exceeds the third temperature threshold T3, the motor is controlled to stop for protection, where T1<T2<T3. When the surface temperature of the roller exceeds T_max, an alarm is issued to prompt the operator to adjust the roller temperature; S5. Shutdown control: After receiving the shutdown instruction, the main controller controls the frequency converter to reduce the motor speed according to the preset deceleration curve, with the deceleration time set to 5-15s. When the motor speed drops to the preset low speed threshold, braking is activated to stop the roller shaft from rotating; After the shutdown is completed, the energy consumption data, fault information, maintenance prompts and the like of this operation are recorded and uploaded to the human-machine interaction interface for display.

8. The control method for a permanent magnet synchronous direct drive rubber mill according to claim 7, characterized in that, In the speed-stable operation control of step S3, the main controller also executes load balancing control. The main controller compares the actual output torque T_real fed back by the torque sensor with the preset load torque curve. If T_real continuously exceeds the corresponding value of the load torque curve for a preset time, it is determined that the rubber material is overloaded, and the output torque is automatically reduced or an alarm is issued.

9. The control method for a permanent magnet synchronous direct drive of a rubber open mill according to claim 8, characterized in that, The torque sensor further includes a main path torque sensor and a secondary path torque sensor respectively arranged on the transmission path of the main roller and the transmission path of the secondary roller. The main controller compares the main path torque T_main and the secondary path torque T_sub in real time. If |T_main-T_sub| / T_avg>10%, where T_avg=(T_main+T_sub) / 2, it is determined that the loads of the two rollers are unbalanced. By adjusting the output frequency of the motor, the loads of the two rollers are automatically redistributed using the friction characteristics between the rubber material and the rollers until the torque difference between the two paths is within the allowable range.

10. The control method for a permanent magnet synchronous direct drive of a rubber open mill according to claim 8, characterized in that, The main controller is further configured to execute energy efficiency optimization control. During the speed-stable operation phase, the main controller calculates the actual output power P_real=T_real×n_real / 9550 at the current operating point according to the real-time monitored actual output torque T_real and actual rotational speed n_real, and judges whether the current operating point is in the high-efficiency zone in combination with the efficiency map of the direct-drive motor; If the current operating point deviates from the high-efficiency zone beyond the threshold, the operating point is guided to the high-efficiency zone by finely adjusting the target rotational speed or prompting the operator to adjust the roller gap, so as to realize the optimization of the system energy efficiency.

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