Single drive differential dual-shaft shredder differential control system

Abstract

This invention discloses a differential speed control system for a single-drive differential dual-shaft shredder, relating to the field of solid waste crushing and shredding equipment control technology. It includes a single-drive force output unit, a main shaft reference transmission unit, a secondary shaft differential coupling unit, a cutter engagement shredding unit, a working condition sensing unit, a differential speed decision unit, and a pressure relief protection unit. This invention, through a main-secondary shaft differential coupling structure under a single drive force source, uses one power source to simultaneously drive the main shaft and secondary shaft, and forms an adjustable speed difference through the differential coupling unit. This solves the problems of complex synchronous control, high cost, and numerous failure points in traditional dual-motor solutions. The structure is more compact, the transmission chain is simpler, and the reliability is higher, while retaining the core advantages of dual-shaft differential shredding.

Description

Technical Field

[0001] This invention relates to the field of solid waste crushing and shredding equipment control technology, specifically a differential speed control system for a single-drive differential speed dual-shaft shredder. Background Technology

[0002] Existing dual-shaft shredders mostly use two motors to drive the main shaft and auxiliary shaft separately. Although this can achieve a certain degree of interlocking crushing, it still has several shortcomings in engineering applications. First, the dual-motor solution needs to solve problems such as speed synchronization, load balancing, and start-stop coordination. The control logic is complex, and during long-term operation, it is prone to problems such as synchronization drift, impact amplification, and high power consumption. Second, for materials that are flexible, easily entangled, contain many impurities, or have uneven particle size, traditional equipment usually relies on a fixed blade distance and a fixed speed ratio. It is difficult to adjust the shredding intensity in real time according to the material resistance, moisture content, and entanglement, resulting in unstable shredding effect. Third, when encountering hard lumps, clumps, entangled materials, or uneven local feeding, the equipment is prone to problems such as material blockage, seizing, instantaneous torque increase, and frequent manual unblocking, affecting continuous operation capability.

[0003] Furthermore, traditional equipment often emphasizes the mechanical interlocking action between the blades, while underutilizing the relative speed difference between the blades and the toothed spacers. This results in the shredding process relying more on simple compression and shearing, lacking the ability to dynamically adjust differential speed for different materials. Especially in scenarios involving industrial solid waste, municipal solid waste, woven bags, films, rubber, and fiber mixtures, where material morphologies vary significantly, using fixed parameters can easily lead to problems such as "able to shred but inefficient," "able to break but prone to clogging," and "able to rotate but unstable." Therefore, there is an urgent need for a shredder differential speed control system that can achieve dual-axis differential speed linkage under single-drive conditions, and possesses real-time sensing, adaptive adjustment, and active pressure relief functions to improve the equipment's adaptability, stability, and continuous operation capability.

[0004] Patent CN106179643B discloses a dual-axis differential speed material shredding control method. The above patent can ensure the shredding effect and efficiency of the material, improve the production output of the equipment, and expand the range of materials that the equipment can shred.

[0005] While ensuring the shredding effect and efficiency of the material, the above-mentioned patent allows the spacing between adjacent blades on the drive shaft to be increased to 3-5mm, which reduces the material requirements of the blades on the drive shaft and greatly reduces the manufacturing cost. However, the dual-motor solution needs to solve problems such as speed synchronization, load balancing and start-stop coordination. The control logic is complex, and it is prone to problems such as synchronization drift, impact amplification and high power consumption during long-term operation.

[0006] Therefore, this application proposes a differential speed control system for a single-drive differential dual-shaft shredder, which uses a main and auxiliary shaft differential coupling structure under a single driving force source to drive the main shaft and auxiliary shaft simultaneously with one power source, and forms an adjustable speed difference through a differential coupling unit. Summary of the Invention

[0007] The purpose of this invention is to provide a differential control system for a single-drive differential dual-shaft shredder, so as to solve the technical problems of complex synchronous control, high cost and many failure points in the traditional dual-motor scheme mentioned in the background art.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a differential control system for a single-drive differential dual-shaft shredder, comprising a single drive force output unit, a main shaft reference transmission unit, a secondary shaft differential coupling unit, a cutter biting and shredding unit, a working condition sensing unit, a differential decision unit, and a pressure relief protection unit. The single drive force output unit is used to provide the sole drive source for the entire machine and drives the main shaft to form a reference rotation via the main shaft reference transmission unit. The counterspindle differential coupling unit is linked to the main spindle reference transmission unit to enable the counterspindle to form an adjustable differential speed relative to the main spindle. The cutting tool meshing and shredding units are respectively set on the main shaft and the secondary shaft to form an interlocking meshing shredding zone between the main shaft and the secondary shaft; The operating condition sensing unit is used to collect motor current, main shaft speed, secondary shaft speed, shaft torque, vibration signal, and temperature rise signal; The differential decision unit is used to construct a mapping relationship between load status and differential parameters based on the signals collected by the condition sensing unit, and output the target differential control quantity; The pressure relief protection unit is used to perform speed reduction, short-term reverse, pulse drive, differential method and local unloading control when abnormal load is detected, so as to achieve adaptive differential adjustment, material blockage suppression and continuous stable operation under single drive conditions.

[0009] Preferably, the single drive force output unit includes one of a variable frequency drive motor, a geared motor, and a servo motor, and the output end of the single drive force output unit is connected to the main shaft through a primary transmission mechanism. The main shaft serves as the speed reference shaft, and the primary transmission mechanism includes one or more of a gear pair, a sprocket pair, and synchronous belt pulley spokes to achieve constant transmission of the main shaft's basic speed and output torque.

[0010] Preferably, the secondary shaft differential coupling unit includes one or more of the following: differential gear assembly, planetary coupling assembly, constant speed ratio coupling assembly, flexible synchronous coupling assembly, or a combination thereof. The secondary shaft differential coupling unit is provided with an adjustable transmission ratio adjustment mechanism to make the speed difference between the secondary shaft and the main shaft continuously adjustable within a preset range, thereby forming a differential shredding mode for different material states.

[0011] Preferably, the cutting tool biting and shredding unit includes a cutter disc, a cutter holder, and a spacer respectively mounted on the main shaft and the auxiliary shaft. The cutter disc and the spacer are arranged alternately along the axial direction, and the main shaft cutter disc and the auxiliary shaft cutter disc form a asynchronous biting relationship in the circumferential direction, so that the material is subjected to shearing, squeezing, pulling and tearing actions simultaneously after entering the shredding zone, thereby improving the crushing efficiency of entangled, tough or blocky materials.

[0012] Preferably, the working condition sensing unit includes at least two of the following: current sensor, speed sensor, torque sensor, vibration sensor, and temperature sensor, and is respectively arranged at the drive end, main shaft end, and auxiliary shaft end. It is used to acquire multi-dimensional state variables corresponding to feed uniformity, instantaneous resistance, tool engagement degree, shaft load change, and thermal state, and input the multi-dimensional state variables into the differential speed decision unit.

[0013] Preferably, the differential speed decision unit includes a working condition identification module, a differential speed mapping module, and a feedback correction module. The working condition identification module is used to identify no-load, light-load, stable-load, off-center load, material blockage trend, and unblocking recovery status based on the signals collected by the working condition sensing unit. The differential speed mapping module is used to map the status to the corresponding target differential speed value, target speed ratio, and target torque distribution coefficient. The feedback correction module is used to perform rolling correction on the target differential speed value based on the real-time deviation to form a closed-loop differential speed control logic.

[0014] Preferably, the differential speed mapping module pre-stores at least two sets of material differential speed parameter libraries, and the different material differential speed parameter libraries correspond to soft and tough, hard and brittle, entangled, mixed or high moisture content materials, respectively. When the working condition identification module determines that the corresponding material state has been entered, the differential speed decision unit outputs the main and auxiliary shaft speed difference, phase difference and shredding dwell time control amount according to the corresponding material differential speed parameter library, so as to match the tool engagement depth with the material crushing characteristics.

[0015] Preferably, the pressure relief protection unit is activated when any warning condition is met, including: The motor current continuously exceeds the threshold, the shaft torque gradient rises abnormally, the main and auxiliary shaft speed difference deviates from the allowable bandwidth, the vibration amplitude exceeds the set upper limit, or the temperature rise exceeds the safety threshold. After the pressure relief protection unit is activated, it performs at least one control action: reducing the base speed of the main spindle, increasing the differential speed between the main and auxiliary spindles, short-term reverse micro-oscillation, intermittent pulse drive, or partial unloading recovery, in order to avoid stalling and maintain the system's recoverable operation.

[0016] Preferably, the control system further includes a tool wear compensation unit. The tool wear compensation unit corrects the differential speed control amount based on the reduction of the effective radius of the tool, the change in shredding resistance and the load fluctuation per unit time, and compensates and adjusts the speed ratio of the main and auxiliary shafts so that the tool maintains a stable meshing gap, shredding particle size and processing efficiency even after the tool wears.

[0017] Preferably, the differential decision unit and the pressure relief protection unit together constitute a hierarchical closed-loop control structure. The hierarchical closed-loop control structure is executed cyclically in the order of working condition identification - differential distribution - synchronous shredding - load monitoring - deviation correction - unblocking and recovery. Under normal working conditions, steady-state differential is used; during the load increase phase, differential control is used; during the abnormal load phase, pressure relief control is used; and after the load is restored, it automatically switches back to steady-state differential to achieve continuous adaptive shredding control under single-drive conditions.

[0018] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention uses a main and auxiliary shaft differential coupling structure under a single driving force source to drive the main shaft and auxiliary shaft simultaneously with one power source, and forms an adjustable speed difference through the differential coupling unit. This solves the problems of complex synchronous control, high cost and many failure points in the traditional dual-motor scheme. The structure is more compact, the transmission chain is simpler and the reliability is higher, while retaining the core advantages of dual-shaft differential shredding. 2. This invention uses a dynamic differential speed decision-making mechanism based on working condition perception to collect current, speed, torque, vibration and temperature rise data in real time, and automatically adjust the speed difference between the main and auxiliary shafts accordingly. This solves the problem that traditional shredding equipment has fixed parameters and is difficult to adapt to soft, tough, hard, brittle, entangled and mixed materials. It can automatically switch differential speed strategies according to the material state, improving crushing adaptability, shredding efficiency and output uniformity. 3. This invention uses pressure relief protection control to address the tendency of material blockage. When the load increases abnormally, it automatically performs speed reduction, reverse fine adjustment, pulse drive or differential amplification to relieve the blockage. This solves the problem of easy blockage, seizing and frequent shutdown of shredders under the conditions of hard blocks, lumps or tangled materials. It significantly reduces the probability of material blockage and the frequency of manual clearing, and improves continuous operation capability and equipment operation safety. 4. This invention compensates for tool wear and corrects it in a closed loop for long-term operation. Based on changes in tool wear, load fluctuations and shredding effect, it compensates and corrects the differential speed parameters, which solves the problems of changes in meshing relationship, unstable crushing particle size and reduced efficiency after tool wear. This allows the equipment to maintain relatively stable shredding quality and load status during long-term use, extends the effective operating cycle and reduces maintenance costs. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the differential control system structure of the present invention; Figure 2 This is a schematic diagram of the differential control process of the present invention; Figure 3 This is a schematic diagram of the pressure relief protection and recovery control of the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Example 1

[0021] Please see Figure 1 , Figure 2 and Figure 3 A differential control system for a single-drive differential dual-shaft shredder, based on the fundamental implementation of a single drive power source coupled with the main and auxiliary differential speeds: This embodiment provides a differential control system for a single-drive differential dual-shaft shredder suitable for solid waste shredding scenarios. The system includes a single drive force output unit, a main shaft reference transmission unit, a secondary shaft differential coupling unit, a cutter biting shredding unit, a working condition sensing unit, a differential decision unit, and a pressure relief protection unit.

[0022] The single-drive output unit uses a variable frequency drive motor as its sole power source. The motor output is connected to the spindle input via a reduction gearbox, and the spindle serves as the speed reference shaft, outputting the basic torque. The spindle output is further connected to a primary transmission mechanism, which can employ any one or a combination of gear pairs, sprocket pairs, or synchronous belt pulley pairs to achieve stable transmission of the spindle's basic speed. In this embodiment, a combination of gear pairs and sprocket pairs is preferred to improve transmission stability and shock resistance.

[0023] The counterspindle differential coupling unit is linked to the main spindle reference transmission unit. The counterspindle is not driven by an independent motor, but rather mechanically coupled to the main spindle via a differential gear mechanism. This differential gear mechanism includes an input gear, a differential sun gear, planetary gears, and a counterspindle output gear. When the main spindle rotates, it drives the differential mechanism to operate synchronously, and the relative angular velocity difference between the counterspindle and the main spindle is changed through a differential adjustment component. The differential adjustment component can be composed of an adjustable center distance mechanism, an adjustable gear ratio assembly, or a clutch switching assembly, thereby allowing the counterspindle speed to have a preset difference from the main spindle speed.

[0024] In the cutter-engaging shredding unit, cutter discs, cutter holders, and spacers are respectively installed on the main shaft and the secondary shaft. The outer edges of the cutter discs and the outer edges of the spacers are arranged axially in a staggered manner. The cutter discs of the main and secondary shafts are kept phase-shifted in the circumferential direction, so that the material entering the shredding zone is first gripped by the cutters and then continuously pulled by the speed difference between the main and secondary shafts. The main shaft is responsible for providing stable traction force, and the secondary shaft is responsible for creating relative displacement, thus constituting a differential shredding mode under single-drive conditions.

[0025] In this embodiment, the operating condition sensing unit includes at least a current sensor and a speed sensor. The current sensor is installed in the motor power supply circuit to detect the real-time load current of the motor; the speed sensor is installed at the end of the main shaft and the end of the auxiliary shaft to collect the real-time speed of the two shafts respectively. The controller determines the current operating condition based on the current value and the speed difference. For example, under no-load or light-load conditions, the controller maintains the basic differential speed value; under increased load conditions, the controller increases the speed difference between the auxiliary shaft and the main shaft to enhance the tearing effect and prevent the material from "dragging and accumulating" between the cutters.

[0026] With this structure, this embodiment realizes the basic function of dual-shaft shredding driven by a single power source, avoiding the complexity brought about by dual-motor synchronous control, while retaining the crushing advantages of dual-shaft differential shredding. Example 2

[0027] Please see Figure 1 , Figure 2 and Figure 3 A differential speed control system for a single-drive differential dual-shaft shredder, specifically designed for enhanced differential speed control of entangled materials: Based on Example 1, this embodiment optimizes materials that are prone to entanglement, such as films, woven bags, fiber ropes, fishing nets, tapes, and strips of cloth, with a focus on enhancing the differential control logic's ability to identify and process "entanglement trends".

[0028] The system incorporates vibration and torque sensors in its operating condition sensing unit. Vibration sensors are mounted on the frame and bearing housings to detect abnormal vibration peaks; torque sensors are positioned at the main shaft input or auxiliary shaft output to detect changes in engagement resistance. The controller has a built-in library of winding material parameters and preset control templates for winding materials, including large main and auxiliary shaft speed differences, long engagement dwell times, and strong transient tensile movements.

[0029] During operation, when the sensor detects one or more of the following characteristics, the controller determines that it has entered the winding enhancement mode: First, the motor current increases in a stepwise manner but does not form a continuous stall; second, the torque fluctuation periodically increases, indicating that the material is winding between the shafts; third, the vibration signal shows a low-frequency periodic peak, indicating that the friction between the tool and the material is enhanced. At this time, the differential speed decision unit will output a higher target differential speed value, so that the sub-shaft maintains a more obvious speed difference relative to the main shaft.

[0030] For example, when processing woven bags and film mixtures, the main shaft maintains a continuous gripping speed at a reference speed, while the auxiliary shaft operates at a slightly lower but stable reverse speed. Due to the speed difference between the main and auxiliary shafts, once the material is gripped by the cutter head, a continuous pulling sensation is created between the main and auxiliary shafts. This prevents the entangled material from accumulating around the shafts and instead causes it to gradually break apart during relative motion. Simultaneously, the pressure relief protection unit does not initiate a forced shutdown at this time. Instead, it releases the entanglement stress through a short-term differential speed amplification, allowing the material to self-untangle without disassembling the machine.

[0031] This embodiment is particularly suitable for fibrous, membrane, and soft strip mixtures, and can significantly reduce the probability of tangling and sticking, and improve continuous feeding capability. Example 3

[0032] Please see Figure 1 , Figure 2 and Figure 3 A differential speed control system for a single-drive differential dual-shaft shredder, designed for low-impact differential control of hard and brittle materials: This embodiment is designed for hard and brittle materials, such as hard plastic blocks, rubber blocks, light metal scraps, compressed hard blocks, and hard lumps containing impurities. It focuses on solving the problems of large impact from hard blocks, sudden changes in tool force, and high shaft vibration.

[0033] The system incorporates a hard and brittle material control template within the differential speed decision unit. Template parameters typically include a small speed difference, high torque stability requirements, and stringent vibration constraints. The controller determines whether to enter the hard and brittle mode by collecting current, torque, and vibration data.

[0034] In hard-brittle mode, the main spindle maintains stable output through a single drive force output unit, while the secondary spindle differential coupling unit limits the speed difference between the main and secondary spindles to a narrow range. This ensures that the action of the tool on the material is primarily shearing and localized compression, avoiding impact-induced tearing caused by excessive differential speed. If the feed is detected to be momentarily too hard, the controller prioritizes a gradual speed increase strategy rather than immediately increasing the differential speed. That is, it first reduces the main spindle acceleration and then fine-tunes the secondary spindle speed difference, thereby reducing the instantaneous impact on the tooth surface and cutting edge.

[0035] For example, when a hard plastic shell enters the shredding zone, the torque will briefly increase, and the current will rise synchronously. However, if the vibration is still within the allowable range, the controller will only perform a small differential speed compensation, allowing the material to gradually break up through multiple interlocking engagements, rather than a one-time high-impact tear. If the vibration peak continues to rise, the system will enter a pressure relief protection state, performing a short-term deceleration and micro-reverse action to reposition the hard block before resuming shredding.

[0036] This embodiment is suitable for scenarios where the uniformity of crushed particle size is required and the risk of material impact is high. It can reduce the probability of tool breakage and extend the life of the shaft system. Example 4

[0037] Please see Figure 1 , Figure 2 and Figure 3 A differential speed control system for a single-drive differential dual-shaft shredder, achieving material blockage detection, pressure relief and recovery, and closed-loop back-cutting: This embodiment focuses on illustrating the collaborative working mode of the pressure relief protection unit and the differential speed decision unit, especially for material blockage trend identification, local jamming relief, and operation recovery logic.

[0038] During operation, the system continuously collects data on the main shaft current, secondary shaft speed, main-secondary shaft speed difference, shaft torque, and vibration signals, and sets multiple threshold levels: the first-level threshold is used for mild load anomaly alerts, the second-level threshold is used for judging material blockage trends, and the third-level threshold is used for triggering forced pressure relief actions. The controller can make judgments based on the data trend within a continuous sampling window rather than single-point data, thereby reducing the probability of false triggers.

[0039] The system determines a material blockage trend when any of the following conditions occur: the motor current continuously rises within a preset time and exceeds the upper limit; the speed difference between the main and auxiliary shafts significantly narrows and cannot recover in a short time; the torque change rate exceeds the set threshold; or the vibration signal exhibits continuous high-amplitude impacts. At this time, the pressure relief protection unit is activated. First, it reduces the base speed of the main shaft to decrease the force on the material; then, it controls the auxiliary shaft to perform a short-term reverse micro-oscillation, causing displacement of the clamping point; if necessary, it uses a pulse-type start-stop method to loosen the blockage and reintroduce it into the engagement zone.

[0040] For example, when processing a mixture containing cardboard and wet clumps of debris, if the cardboard becomes laterally stuck, the controller immediately decelerates upon detecting a rapid increase in current. It then instructs the secondary shaft to perform a small-angle reverse oscillation, using the speed difference to "shake" the stuck material edges apart, gradually restoring normal differential shredding. This process requires no manual disassembly and can restore production continuity in a short time.

[0041] Furthermore, during the recovery process, the system adopts a back-cut strategy, that is, it first runs in a low differential speed and low torque mode for a period of time, and after the current and vibration return to normal, it gradually recovers to the steady-state differential speed parameters, thereby avoiding the re-induction of material blockage due to too fast recovery. Example 5

[0042] Please see Figure 1 , Figure 2 and Figure 3 A differential speed control system for a single-drive differential dual-shaft shredder achieves tool wear compensation and long-term stable operation. This embodiment illustrates how the system maintains stable shredding performance after the tool wears, focusing on the tool wear compensation unit in the claims.

[0043] During long-term operation, the cutting edges of the main shaft cutter head and the auxiliary shaft cutter head will wear down due to repeated contact with the material. Cutter wear leads to a reduction in the effective engagement depth and changes in the relative cutting relationship between the cutter and the toothed spacer, thus affecting shredding efficiency and output particle size. Therefore, this embodiment establishes a cutter wear compensation model in the controller. The model considers at least the following parameters: the attenuation of the effective cutter radius, the change in the average current per unit time, the change in the torque fluctuation amplitude, and the change in material throughput time.

[0044] When the system detects a slight increase in the average current, increased torque fluctuation, and coarser output particle size under the same material conditions, the controller determines that the tool wear has reached the compensation trigger condition. At this time, the differential speed decision unit automatically corrects the main and auxiliary spindle speed ratio, appropriately increasing the differential speed value of the auxiliary spindle relative to the main spindle to compensate for the insufficient tearing caused by the decrease in tool cutting capability. Simultaneously, if the wear is mainly manifested in localized tool dulling, the controller can use a finer-grained differential speed control step size to reduce the impact of localized failures on the overall performance.

[0045] For example, after two weeks of continuous treatment of industrial solid waste, if the system detects that the current is significantly higher under the same load than the initial operating conditions, and the proportion of insufficiently shredded long strips in the output increases, the controller will add the tool wear compensation to the differential speed control value, slightly increasing the speed difference between the main and auxiliary shafts. Through this compensation, the equipment can maintain relatively stable shredding quality without replacing the tools.

[0046] This embodiment enables the system to maintain performance by no longer relying solely on mechanical backlash, but by dynamically compensating for tool status through control logic, thereby improving the long-term applicability and maintenance economy of the entire machine. Example 6

[0047] Please see Figure 1 , Figure 2 and Figure 3 A differential speed control system for a single-drive differential dual-shaft shredder, featuring multi-material adaptive parameter library switching: This embodiment further illustrates the material identification and parameter switching capabilities of the differential decision unit, which is suitable for scenarios involving the mixing of multiple materials and significant fluctuations in feed composition.

[0048] The differential speed decision unit has multiple preset material differential speed parameter libraries. Each parameter library corresponds to a major material type, including but not limited to soft and tough, hard and brittle, entangled, mixed, and high-moisture materials. Each parameter library contains at least the following parameters: target main and auxiliary shaft speed difference, torque limit, allowable vibration range, pressure relief start threshold, and recovery cut-back threshold.

[0049] During system operation, the operating condition sensing unit first collects data on current, torque, speed difference, vibration, and temperature rise within a short time window. Then, the operating condition identification module classifies and judges the material's state. For example, if the current rises steadily, vibration is low, and torque is relatively stable, it tends to be a soft and pliable material; if the torque fluctuates greatly but the vibration is strong, it may be a hard and brittle mixed material; if the current and vibration exhibit periodic shaking synchronously, it is more likely to be an entangled material. After the judgment result is output, the controller switches to the corresponding parameter library.

[0050] For example, in a mixed packaging scenario for kitchen waste, the system first identifies a high proportion of wet, soft materials and adopts a higher differential speed and greater stretching mode. Subsequently, upon detecting the intrusion of a hard plastic box, the system switches to a low-impact mode, briefly reducing the speed difference between the main and auxiliary shafts to prevent excessive impact from the hard block. When the mixture of soft and hard materials increases again, it switches back to the mixed mode and performs dynamic differential oscillation. Through this parameter library switching method, the system achieves continuous adaptation under multiple material conditions.

[0051] This embodiment enables the control system to have a "recognition-switching-feedback-re-recognition" cycle capability, further improving the stability of the single-drive differential dual-shaft shredder when facing complex materials. Example 7

[0052] Please see Figure 1 , Figure 2 and Figure 3 A differential control system for a single-drive differential dual-shaft shredder, achieving layered closed-loop differential control and load distribution: This embodiment provides a more detailed explanation of the collaborative closed-loop process between the differential decision unit and the pressure relief protection unit.

[0053] The control system adopts a hierarchical control structure. The first layer is the working condition identification layer, which is responsible for determining the current load type from sensor data. The second layer is the differential distribution layer, which is responsible for calculating the target differential value, target speed ratio, and target torque distribution coefficient. The third layer is the execution feedback layer, which is responsible for driving the differential coupling unit and the spindle drive unit to perform adjustments. The fourth layer is the safety protection layer, which is responsible for triggering pressure relief and recovery actions under abnormal conditions.

[0054] During operation, the system can define a target differential control value ΔV, which is derived from the combined results of operating conditions, material type, and load trends. The controller does not directly use a single fixed value, but updates dynamically according to the following logic: when the load increases but has not yet reached the stall danger zone, ΔV is gradually increased; when the load decreases, ΔV is gradually decreased to save energy; when the load suddenly increases and is accompanied by excessive vibration, the pressure relief protection is activated, temporarily amplifying ΔV and coordinating with deceleration.

[0055] For example, during a mixing process, the system detects a gradual increase in main shaft current and torque, but the rotational speed has not yet decreased significantly, indicating that the material has entered a heavy load state. The controller first slightly increases the speed difference of the auxiliary shaft. If the vibration then increases rapidly, it indicates abnormal friction or material blockage. The controller immediately switches to the pressure relief mode, causing the main and auxiliary shafts to perform short-term reverse fine-tuning, and then gradually restores the normal operating state. The entire process realizes closed-loop control of "load sensing - differential speed adjustment - abnormal protection - recovery operation".

[0056] As can be seen from this embodiment, the differential control of the present invention is not a simple mechanical differential, but a complete control system that includes load distribution, state recognition, control switching and safety recovery, and therefore can more fully support the system function limitations in the aforementioned claims.

[0057] The control principle of this invention is not simply "rotate faster" or "rotate slower", but rather actively manages the relative linear velocity difference between the main shaft and the secondary shaft to ensure that the blade tip and the toothed spacer always form differential tearing conditions suitable for the current material characteristics.

[0058] The instantaneous angular velocities of the main spindle and the secondary spindle can be denoted as ω1 and ω2, respectively; the equivalent radius of the tool tip can be denoted as R1; and the equivalent radius of the toothed spacer can be denoted as R2. Then, the effective relative linear velocity of the meshing region can be expressed as: V = ω1·R1 + ω2·R2 When the two shafts rotate in opposite directions, the larger V is, the stronger the clamping and tearing effect on the material; when V is too large, it may cause increased energy consumption and intensified impact; when V is too small, it will reduce shredding efficiency and increase the probability of entanglement. Therefore, this invention adjusts V to a target range that matches the material state through a control system.

[0059] Furthermore, the control system generates a differential speed correction ΔV based on the feed characteristics and load feedback, which can be expressed by the following relationship: ΔV=f(I,T,n,L,M) Where: I is the motor current or current fluctuation value; T is the shaft torque or torque fluctuation value; n is the difference in speed between the main and auxiliary shafts; L is the feed load level; M is the material property parameter, including at least hardness, toughness, moisture content, entanglement and blockiness grade.

[0060] Based on the preset target shredding state, the controller adjusts the main and auxiliary shaft speeds in real time, which enhances the biting and tearing ability of the system under high load, reduces ineffective energy consumption under light load, and quickly enters the pressure relief action when the tendency of material blockage occurs.

[0061] The differential control process of this invention can be summarized as follows: S1: Operating Condition Identification After the system starts, it collects the motor's no-load current, the initial speed of the main and auxiliary shafts, the status of the feed gate, and historical operating parameters to establish a baseline for the current operating condition. If the type of feed material is known, the corresponding differential speed parameter template is loaded.

[0062] S2: Target Differential Setting The controller calculates the target speed ratio, phase difference, and speed difference between the main shaft and the secondary shaft based on the material type and the current load. For materials that are tough and easily entangled, the differential speed is increased appropriately; for materials that are brittle and easily broken, the differential speed is decreased to reduce excessive impact.

[0063] S3: Synchronous Reverse Drive After the single drive power source outputs, the main shaft and the countershaft rotate in opposite directions under the action of the differential transmission mechanism. The main shaft provides a stable reference torque, and the countershaft is adjusted according to the differential control signal to ensure that the two shafts form a stable relative motion in the meshing area.

[0064] S4: Differential bite tearing After the material is fed between the two shafts, it is first gripped by the blade tip, and then a speed difference is created between the blade tip and the outer edge of the toothed spacer. The blade tip applies an initial pulling force to the material, while the toothed spacer restricts and shears the material, causing large pieces of material to gradually break down and be discharged from the outlet.

[0065] S5: Load Feedback Correction During the shredding process, the controller continuously monitors changes in current, torque, and shaft speed. When the load increases but does not reach the stall threshold, the system automatically increases the differential speed or reduces the local feed speed; when the load increases abnormally, the system enters the anti-blocking mode and outputs short-term reverse fine-tuning or pulse-type load reduction control.

[0066] S6: Complete material discharge and status recovery After the material passes through, the system returns to normal differential speed mode or energy-saving mode, waiting for the next batch of material to be fed. During long-term operation, the controller can also gradually adjust the target differential speed parameters according to the degree of tool wear to compensate for the change in effective radius caused by tool wear.

[0067] Working principle: This system uses a single power source as the core of the machine's drive. The torque output by the motor is first transmitted to the main shaft via the main shaft reference transmission unit, enabling the main shaft to form a stable reference rotation. Subsequently, the secondary shaft differential coupling unit, in conjunction with the main shaft, establishes an adjustable relative speed difference, causing the secondary shaft to operate in the opposite direction to the main shaft with a speed difference, thus forming a continuously changing shredding engagement relationship between the main and secondary shafts. Due to the staggered arrangement of cutter discs, cutter holders, and toothed spacers on the main and secondary shafts, the material entering the shredding zone is simultaneously subjected to gripping, shearing, squeezing, and pulling actions, thereby being gradually crushed and conveyed to the discharge end.

[0068] During system operation, the operating condition sensing unit continuously collects signals such as motor current, main and auxiliary shaft speeds, shaft torque, vibration, and temperature rise, and inputs these signals into the differential speed decision unit. Based on different material states, load variation trends, and tool engagement characteristics, the differential speed decision unit dynamically calculates the target differential speed control value, and then performs rolling corrections on the auxiliary shaft speed difference, main and auxiliary shaft speed ratio, and torque distribution relationship. This ensures that the equipment always maintains a differential shredding state suitable for the current material characteristics, avoiding efficiency fluctuations and material blockage risks caused by fixed parameters.

[0069] When the system detects abnormal load, sudden increase in torque, abnormal reduction in speed difference, or excessive vibration, the pressure relief protection unit immediately intervenes, executing control actions such as speed reduction, short-term reverse, pulse drive, or differential amplification to first release the stuck stress and then restore the normal differential state. Thus, the system forms a closed-loop control logic of "sensing—decision-execution—feedback—pressure relief and recovery," achieving dual-axis differential tearing, active anti-blocking, and continuous stable operation under single-drive conditions.

[0070] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A differential speed control system for a single-drive differential dual-shaft shredder, comprising a single-drive force output unit, a main shaft reference transmission unit, a secondary shaft differential coupling unit, a cutter biting and shredding unit, a working condition sensing unit, a differential speed decision unit, and a pressure relief protection unit, characterized in that: The single drive force output unit is used to provide the only drive source for the whole machine, and drives the spindle to form a reference rotation through the spindle reference transmission unit; The counterspindle differential coupling unit is linked to the main spindle reference transmission unit to enable the counterspindle to form an adjustable differential speed relative to the main spindle. The cutting tool meshing and shredding units are respectively set on the main shaft and the secondary shaft to form an interlocking meshing shredding zone between the main shaft and the secondary shaft; The operating condition sensing unit is used to collect motor current, main shaft speed, secondary shaft speed, shaft torque, vibration signal, and temperature rise signal; The differential decision unit is used to construct a mapping relationship between load status and differential parameters based on the signals collected by the condition sensing unit, and output the target differential control quantity; The pressure relief protection unit is used to perform speed reduction, short-term reverse, pulse drive, differential method and local unloading control when abnormal load is detected, so as to achieve adaptive differential adjustment, material blockage suppression and continuous stable operation under single drive conditions.

2. The differential speed control system for a single-drive differential dual-shaft shredder according to claim 1, characterized in that: The single drive force output unit includes one of a variable frequency drive motor, a geared motor, and a servo motor. The output end of the single drive force output unit is connected to the main shaft through a primary transmission mechanism. The main shaft serves as the speed reference shaft. The primary transmission mechanism includes one or more of a gear pair, a sprocket pair, and a synchronous belt pulley spoke, in order to achieve the constant transmission of the main shaft's basic speed and output torque.

3. The differential speed control system for a single-drive differential dual-shaft shredder according to claim 1, characterized in that: The secondary shaft differential coupling unit includes one or more of the following structures: differential gear assembly, planetary coupling assembly, constant speed ratio coupling assembly, flexible synchronous coupling assembly, or a combination thereof. The secondary shaft differential coupling unit is provided with an adjustable transmission ratio adjustment mechanism to make the speed difference between the secondary shaft and the main shaft continuously adjustable within a preset range, thereby forming a differential shredding mode for different material states.

4. The differential speed control system for a single-drive differential dual-shaft shredder according to claim 1, characterized in that: The cutting tool biting and shredding unit includes a cutter disc, a cutter holder, and a spacer respectively installed on the main shaft and the auxiliary shaft. The cutter disc and the spacer are arranged alternately along the axial direction, and the main shaft cutter disc and the auxiliary shaft cutter disc form a asynchronous biting relationship in the circumferential direction, so that the material is subjected to shearing, squeezing, pulling and tearing actions simultaneously after entering the shredding zone, thereby improving the crushing efficiency of entangled, tough or blocky materials.

5. The differential speed control system for a single-drive differential dual-shaft shredder according to claim 1, characterized in that: The working condition sensing unit includes at least two of the following: current sensor, speed sensor, torque sensor, vibration sensor, and temperature sensor, which are respectively arranged at the drive end, main shaft end, and auxiliary shaft end. It is used to acquire multi-dimensional state variables corresponding to feed uniformity, instantaneous resistance, tool engagement degree, shaft load change, and thermal state, and input the multi-dimensional state variables into the differential speed decision unit.

6. The differential speed control system for a single-drive differential dual-shaft shredder according to claim 1, characterized in that: The differential speed decision unit includes a working condition identification module, a differential speed mapping module, and a feedback correction module. The working condition identification module is used to identify no-load, light-load, stable-load, off-center-load, material blockage trend, and unblocking recovery status based on the signals collected by the working condition sensing unit. The differential speed mapping module is used to map the status to the corresponding target differential speed value, target speed ratio, and target torque distribution coefficient. The feedback correction module is used to perform rolling corrections on the target differential value based on the real-time deviation, so as to form a closed-loop differential control logic.

7. The differential speed control system for a single-drive differential dual-shaft shredder according to claim 6, characterized in that: The differential speed mapping module pre-stores at least two sets of material differential speed parameter libraries, with different material differential speed parameter libraries corresponding to soft and tough, hard and brittle, entangled, mixed or high moisture content materials, respectively. When the working condition identification module determines that the corresponding material state has been entered, the differential speed decision unit outputs the main and auxiliary shaft speed difference, phase difference and shredding dwell time control amount according to the corresponding material differential speed parameter library, so as to match the tool engagement depth with the material crushing characteristics.

8. The differential speed control system for a single-drive differential dual-shaft shredder according to claim 1, characterized in that: The pressure relief protection unit is activated when any of the following warning conditions are met: The motor current continuously exceeds the threshold, the shaft torque gradient rises abnormally, the main and auxiliary shaft speed difference deviates from the allowable bandwidth, the vibration amplitude exceeds the set upper limit, or the temperature rise exceeds the safety threshold. After the pressure relief protection unit is activated, it performs at least one control action: reducing the base speed of the main spindle, increasing the differential speed between the main and auxiliary spindles, short-term reverse micro-oscillation, intermittent pulse drive, or partial unloading recovery, in order to avoid stalling and maintain the system's recoverable operation.

9. The differential speed control system for a single-drive differential dual-shaft shredder according to claim 1, characterized in that: The control system also includes a tool wear compensation unit. The tool wear compensation unit corrects the differential speed control amount based on the reduction of the effective radius of the tool, the change in shredding resistance and the load fluctuation per unit time, and compensates and adjusts the speed ratio of the main and auxiliary shafts so that the tool maintains a stable meshing gap, shredding particle size and processing efficiency even after the tool wears.

10. The differential speed control system for a single-drive differential dual-shaft shredder according to claim 1, characterized in that: The differential decision unit and the pressure relief protection unit together constitute a hierarchical closed-loop control structure. The hierarchical closed-loop control structure is executed cyclically in the order of working condition identification - differential distribution - synchronous shredding - load monitoring - deviation correction - unblocking and recovery. Under normal working conditions, steady-state differential is used, differential control is used during the load increase phase, pressure relief control is used during the abnormal load phase, and it automatically switches back to steady-state differential after the load is restored, so as to achieve continuous adaptive shredding control under single-drive conditions.

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