Bearing channel variable-speed grinding system and control method

Abstract

The invention relates to the technical field of bearing machining, and particularly discloses a bearing channel variable-speed grinding system which comprises a main shaft driving unit used for driving a grinding wheel to rotate, a workpiece shaft driving unit used for driving a workpiece to rotate, a current sensing unit, a dimensional deviation detection unit and a controller. The controller is used for executing a first speed regulation mode when the real-time grinding wheel linear speed is lower than a first preset threshold value in the grinding process, specifically, the workpiece shaft driving unit is controlled to keep the rotating speed constant, and the main shaft driving unit is controlled to increase the rotating speed; and when the dimensional deviation detection unit detects that the machining dimensional deviation tends to increase, a second speed regulation mode is executed, specifically, the main shaft driving unit is controlled to keep the rotating speed constant, and the workpiece shaft driving unit is controlled to increase the rotating speed. According to the control method of the bearing channel variable-speed grinding system, the bearing channel variable-speed grinding system needs to carry out speed regulation mode selection. According to the scheme, the grinding state can be sensed in real time, the optimal speed regulation strategy is automatically executed, and therefore the machining quality is improved.

Description

Technical Field

[0001] This invention relates to the field of bearing machining technology, specifically to a bearing raceway variable speed grinding system and control method. Background Technology

[0002] As the core load-bearing and moving surface of a bearing, the bearing raceway's geometric accuracy (such as roundness) and surface quality (such as waviness) directly determine the bearing's rotational accuracy, vibration and noise levels, and fatigue life. Grinding is the finishing process that ultimately shapes the raceway. During this process, the speed matching relationship between the spindle driving the grinding wheel and the workpiece shaft driving the bearing rings is the core parameter that determines the grinding quality.

[0003] Currently, bearing raceway grinding machines generally use the following two traditional control methods: The first type is the fixed speed ratio mode: the speed ratio between the spindle and the workpiece axis is set empirically before machining (e.g., fixed at 3:1 or 5:2) and remains unchanged throughout the machining process. This method completely ignores the dynamic changes during machining: firstly, it does not consider the different inherent requirements of grinding linear speed for workpieces with different inner diameters. For example, the required workpiece speed should differ between a 35mm inner diameter ring and a 50mm inner diameter ring to obtain uniform grinding; secondly, as machining progresses, the wear of the grinding wheel causes its diameter to decrease, which directly leads to a decrease in grinding linear speed, affecting grinding efficiency and quality.

[0004] The second method is a simple segmented speed control mode: the workpiece size is roughly divided into several ranges (such as small, medium, and large sizes), and a fixed speed ratio range is set for each range. Although this method partially considers the workpiece size, the adjustment granularity is coarse, and it still relies on the operator's experience to select the range and manually fine-tune the parameters, making it difficult to achieve precise and consistent control.

[0005] To address the quality issues arising from empirical control, particularly waviness defects, existing technologies have proposed several parameter optimization schemes based on process mechanisms. For example, Chinese Patent CN116587086A (Prior Document 1) discloses a "Method for Controlling Waviness in Bearing Surface Grinding." This scheme recognizes that when the ratio (N1 / N2) of the grinding wheel speed (N1) to the workpiece speed (N2) is an integer, regular periodic waviness is easily generated. Therefore, its core lies in presetting a set of non-integer speed ratios, preferably infinite non-repeating decimals, before processing. This scheme transforms the important process experience of "avoiding integer multiples of speed ratios" into specific, executable static parameter setting rules, representing a significant improvement over purely empirical settings. However, this scheme is essentially still an "optimized static preset." Once the parameters are set before processing, they remain unchanged throughout the grinding process, failing to address the two core dynamic variables: "dynamic wear of the grinding wheel" and "real-time changes in the workpiece's quality state." When wear of the grinding wheel causes changes in linear velocity, or when the workpiece exhibits roundness or dimensional deviations, the preset "optimization ratio" is no longer optimal and may even lead to new problems.

[0006] To address the issue of decreased linear velocity caused by grinding wheel wear, existing technologies have proposed compensation schemes. For example, Chinese Patent No. CN104889888A (Prior Document 2) discloses "A Constant Linear Velocity Control System and Control Method for Grinding Wheels in a Grinding Machine." This system monitors the displacement of the grinding wheel dresser through a displacement sensor, indirectly obtaining the change in grinding wheel diameter, and adjusts the spindle speed accordingly to maintain a constant linear velocity of the grinding wheel. This scheme achieves compensation for changes in grinding wheel diameter. However, its technical means rely on the discrete event of "grinding wheel dressing," which is an intermittent and offline compensation, unable to achieve a smooth and timely response to continuous real-time wear during grinding. More importantly, this scheme only focuses on maintaining the constant linear velocity of the single variable "grinding wheel linear velocity," without considering synergistic optimization with the "workpiece spindle speed." When facing small workpieces requiring increased speed to ensure grinding uniformity, or when machining dimensional deviations increase due to clamping, blank, or other issues, single constant linear velocity control proves inadequate, failing to guarantee final geometric accuracy and surface quality. Summary of the Invention

[0007] The present invention aims to provide a bearing groove variable speed grinding system and control method, which can sense the grinding status in real time and automatically execute the optimal speed adjustment strategy, thereby improving the processing quality.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A bearing groove variable speed grinding system includes a spindle drive unit for driving the grinding wheel to rotate, a workpiece shaft drive unit for driving the workpiece to rotate, and further includes: A current sensing unit is used to monitor the operating current of the spindle drive unit; The dimensional deviation detection unit is used for online detection of machining dimensional deviations of workpieces; The controller is connected to the spindle drive unit, the workpiece axis drive unit, the current sensing unit, and the dimensional deviation detection unit. The controller is used for: The real-time linear velocity of the grinding wheel is calculated based on the monitoring data from the current sensing unit. During the grinding process, when the real-time grinding wheel linear speed is lower than the first preset threshold, the first speed regulation mode is executed: the workpiece shaft drive unit is controlled to maintain a constant rotation speed, and the spindle drive unit is controlled to increase the rotation speed. When the dimension deviation detection unit detects an increasing trend in the machining dimension deviation, the second speed regulation mode is executed: the spindle drive unit is controlled to maintain a constant speed, and the workpiece shaft drive unit is controlled to increase its speed.

[0009] The principle and advantages of this scheme are: 1. Automatic mode switching based on dual-source signal feedback is achieved: The system abandons the preset method of fixed or segmented speed ratios and introduces two independent real-time feedback signal sources—a current signal (used to calculate the grinding wheel linear speed) and a dimensional deviation trend signal. Based on these two signals, the controller can automatically determine the main problem in the current processing: whether it is insufficient grinding wheel linear speed or a problem with the uniformity of workpiece grinding. For different problems, the system automatically executes two completely different speed control strategies (first speed control mode or second speed control mode), thus realizing the transformation from open-loop preset to closed-loop dynamic adjustment.

[0010] 2. Two targeted speed control strategies are proposed: To address the contradiction of "reduced linear speed due to grinding wheel wear," a first speed control mode (constant workpiece axis speed, increased spindle speed) is adopted to directly compensate for the loss of linear speed. To address the contradiction of "increased machining dimensional deviations," a second speed control mode (constant spindle speed, increased workpiece axis speed) is adopted, optimizing grinding uniformity by increasing the workpiece speed. These two strategies directly address different root causes of the problem, overcoming the limitations of traditional single speed ratio or single axis speed control, and achieving coordinated optimization of spindle and workpiece axis speeds.

[0011] Preferably, as an improvement, the controller is further configured to: when the workpiece machining dimension deviation is less than the preset value of machining dimension deviation set in the controller, and the roundness deviation value shows an increasing trend, it serves as one of the trigger conditions for executing the second speed regulation mode.

[0012] Beneficial effect: A trigger condition based on workpiece size has been added to the second speed control mode. For workpieces within a specific size range, the system can activate the second mode in advance or pre-set according to this condition to adapt to the specific requirements of grinding uniformity for workpieces of that size.

[0013] Preferably, as an improvement, it also includes a human-machine interaction unit for inputting workpiece parameters. In specific use, workpiece parameters may include model, specifications, processing dimensions, etc.

[0014] Preferably, as an improvement, the controller further includes conflict decision logic: when the real-time grinding wheel linear speed is lower than a first preset threshold, and the size deviation detection unit detects that the machining size deviation has an increasing trend, the second speed regulation mode is executed first.

[0015] Beneficial Effects: This conflict decision-making logic provides a clear solution path for complex abnormal conditions that may occur during machining. When the system simultaneously faces two problems—insufficient grinding wheel linear speed and worsening machining dimensional deviations—simple parallel or sequential processing may lead to quality issues. This logic establishes real-time quality defect signals as the highest priority decision-making criterion. The technical consideration is that "increasing dimensional deviation trend" is an urgent signal directly indicating that the workpiece is about to exceed tolerances and be scrapped; failure to intervene immediately will result in irreversible losses. "Low linear speed" mainly affects grinding efficiency and long-term tool condition, and its impact can be mitigated through subsequent compensation. Therefore, prioritizing the execution of the second speed regulation mode (constant spindle speed, increased workpiece axis speed) directly addresses dimensional deviations, allowing for the most direct intervention in grinding force distribution and quickly curbing the worsening deviation trend. This logic simulates the decision-making of experienced operators in emergency situations, but automates the process with defined rules, avoiding hesitation or errors in human judgment. It ensures that the system can automatically make the least damaging and fastest response in complex conditions, improving the system's reliability under abnormal conditions.

[0016] Preferably, as an improvement, the controller further includes execution process taboo avoidance logic: Obtain the number of finished steel balls in the workpiece; during the grinding process, calculate in real time the ratio of the actual spindle speed to the actual workpiece spindle speed. When the difference between this ratio and an integer multiple of the number of finished steel balls is less than a preset tolerance, adjust the speed of the spindle drive unit or the workpiece spindle drive unit so that the ratio deviates from the integer multiple. The speed adjustment method is as follows: in the currently executed speed regulation mode, increase the speed of the drive unit that is controlled to remain constant.

[0017] Beneficial effects: It adds the function of real-time monitoring and adjustment of the ratio of spindle speed to workpiece spindle speed. When this ratio approaches an integer multiple of the number of finished steel balls, the system adjusts the speed to deviate from it, so as to avoid regular grinding marks that may occur under this ratio.

[0018] Preferably, as an improvement, the controller further includes a constant linear velocity compensation module, the constant linear velocity compensation module comprising: Based on the real-time current data of the current sensing unit, the real-time diameter and real-time linear velocity of the grinding wheel are continuously calculated. By fine-tuning the output frequency of the spindle drive unit, the real-time linear velocity is maintained within the preset target linear velocity range; The constant linear speed compensation module operates continuously in the first speed regulation mode, the second speed regulation mode, and the grinding process without mode switching.

[0019] Beneficial Effects: This solution enables online and continuous measurement and compensation of grinding wheel diameter and linear velocity. By establishing and applying a current-diameter mapping model, the system can continuously calculate the real-time grinding wheel diameter and linear velocity during grinding without relying on discrete events such as grinding wheel dressing. This method overcomes the shortcomings of existing technologies such as CN104889888A, which rely on offline measurement and have delayed response, and can provide a smooth and timely dynamic response to wear, ensuring the stability of the basic grinding parameters.

[0020] Secondly, this solution enables continuous operation of an independent closed loop under all working conditions (including both speed control modes and conventional grinding). This means that regardless of whether the system triggers a mode switch due to a specific problem, the constant linear speed compensation module ensures that the core process parameter of the grinding wheel linear speed remains constant in the background. Especially in the second speed control mode (constant spindle speed), the module ensures the dynamic accuracy of the "constant speed" state through continuous fine-tuning of the "constant speed" setpoint.

[0021] Preferably, as an improvement, when the operating current detected by the current sensing unit exceeds a safety threshold, an emergency stop signal is triggered to control the bearing groove variable speed grinding system to stop operation. This solution addresses the issue of abnormal current spikes caused by grinding wheel breakage, severe impacts, or other anomalies. This logic enables a rapid response and emergency stop, effectively preventing equipment damage and safety accidents. Preferably, as an improvement, in the second speed regulation mode, the constant linear velocity compensation module achieves constant grinding wheel linear velocity by finely adjusting the "constant rotation speed" setting range value of the spindle drive unit.

[0022] Beneficial effects: In the second speed control mode, the controller macroscopically commands "constant spindle speed," but the constant linear velocity compensation module fine-tunes this "constant speed" baseline value in the background to counteract the effects of continued wear on the grinding wheel. This ensures that "constant spindle speed" is not a rigid command, but a dynamic and guaranteed stable state, making the execution of the second speed control mode more precise and effective.

[0023] Preferably, as an improvement, it further includes a speed feedback unit connected to the controller. The speed feedback unit is used to collect the actual speeds of the spindle drive unit and the workpiece shaft drive unit in real time. The controller performs closed-loop speed regulation on the corresponding drive unit according to the actual speed to improve control accuracy.

[0024] Preferably, as an improvement, the controller accesses a process parameter database; the process parameter database stores process parameters related to the workpiece, the process parameters including at least one of the first preset threshold and the target linear velocity range.

[0025] Beneficial effects: This solution digitizes and standardizes optimal process parameters through a database. The system can quickly retrieve verified optimal parameters (such as initial rotational speed and threshold) based on workpiece information, significantly reducing reliance on operator experience and improving debugging efficiency and production standardization.

[0026] The present invention also provides a control method for a bearing raceway variable speed grinding system, which requires the use of the bearing raceway variable speed grinding system, and further includes the following steps: Real-time monitoring steps: During the grinding process, the operating current of the spindle motor that drives the grinding wheel is monitored in real time, and the machining dimensional deviation of the workpiece is detected online; Model Decision and Implementation Steps: Calculate the real-time linear velocity of the grinding wheel based on the operating current; If the real-time grinding wheel linear speed is lower than the first preset threshold, the first speed regulation mode is executed: the workpiece shaft speed driving the workpiece rotation is kept constant, and the speed of the spindle motor is increased; If an increasing trend in the machining dimensional deviation is detected, the second speed regulation mode is executed: the speed of the spindle motor is kept constant, while the speed of the workpiece axis is increased.

[0027] Preferably, as an improvement, the mode decision-making and execution steps further include: If the real-time grinding wheel linear speed is lower than the first preset threshold, and at the same time an increasing trend in the machining size deviation is detected, the second speed regulation mode is executed first.

[0028] Preferably, as an improvement, the conditions for executing the second speed regulation mode further include: when the workpiece processing dimension deviation is less than the preset value of processing dimension deviation set in the controller, and the roundness deviation value shows an increasing trend.

[0029] Preferably, as an improvement, it also includes process taboo avoidance steps: Obtain the number of finished steel balls for the workpiece; The ratio of the actual spindle speed to the actual workpiece spindle speed is calculated in real time, and it is determined whether the ratio is close to an integer multiple of the number of finished steel balls. If so, adjust the speed of the spindle or workpiece axis to disrupt the approximation relationship between the ratio and an integer multiple; The method for adjusting the speed is as follows: in the currently executed speed adjustment mode, increase the speed of the shaft that is kept constant.

[0030] Preferably, as an improvement, a constant linear velocity compensation step is also included: Based on the real-time monitored operating current, the real-time diameter and real-time linear velocity of the grinding wheel are continuously calculated. Compare the real-time linear velocity with the preset target linear velocity; Based on the comparison results, the drive frequency of the spindle motor is finely adjusted to maintain a constant linear velocity; The constant linear velocity compensation step is continuously executed in the first speed regulation mode, the second speed regulation mode, and the grinding process without mode switching.

[0031] Preferably, as an improvement, in the second speed regulation mode, the constant linear velocity compensation step is achieved by fine-tuning the "constant speed" setting range value of the spindle motor.

[0032] Preferably, as an improvement, a speed closed-loop correction step is also included: Real-time acquisition of the actual rotational speeds of the spindle and workpiece axis; Based on the deviation between the actual rotational speed and the target rotational speed, the speed control command of the corresponding drive unit is dynamically corrected.

[0033] Preferably, as an improvement, the method further includes a parameter initialization step: based on information related to the workpiece, querying a process parameter database to obtain process parameters, wherein the process parameters include at least one of the first preset threshold and the target linear velocity range.

[0034] Preferably, as an improvement, a safety monitoring step is also included: real-time monitoring of the operating current; and performing an emergency stop operation when the operating current exceeds a safety threshold. This bearing raceway variable speed grinding system and control method monitors current and dimensional deviations in parallel and executes two different speed regulation strategies according to preset logic (the first speed regulation mode compensates for linear velocity, and the second speed regulation mode corrects problems caused by dimensional deviations).

[0035] Furthermore, this invention ensures optimal system response under complex abnormal operating conditions by introducing conflict decision rules; enhances adaptability and prevention capabilities for specific operating conditions through size-based preset triggering; internalizes core industry experience into automated execution rules through process taboo avoidance steps, suppressing specific defects at the source; provides a stable process foundation for the entire process through continuously running constant linear velocity compensation steps; and together with steps such as speed closed-loop correction and safety monitoring, it constitutes a precision-controllable, stable, reliable, and safe automated solution. This method integrates dynamic perception, intelligent decision-making, and precise execution, effectively improving the consistency of processing quality, equipment utilization, and the level of production automation. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the structural relationship of Embodiment 1 of the present invention.

[0037] Figure 2 This is a flowchart of a control method for a bearing groove variable speed grinding system according to Embodiment 2 of the present invention.

[0038] Figure 3 This is a flowchart illustrating the selection of two speed regulation modes in Embodiment 1 of the present invention. Detailed Implementation

[0039] The following detailed description illustrates the specific implementation method: The basic implementation examples are as follows: Figures 1 to 3 As shown.

[0040] Example 1 Combination Figure 1 A bearing groove variable speed grinding system includes a spindle drive unit, a workpiece shaft drive unit, a current sensing unit, a dimensional deviation detection unit, a controller, and optional human-machine interaction unit and speed feedback unit.

[0041] The spindle drive unit includes a spindle servo motor and its matching servo driver, which are used to drive the grinding wheel to rotate.

[0042] The workpiece axis drive unit includes a workpiece axis servo motor and its matching servo driver, used to drive the workpiece (bearing ring) to rotate.

[0043] The current sensing unit is a Hall current sensor installed in the power supply circuit of the spindle servo motor, used to monitor its operating current in real time.

[0044] The dimensional deviation detection unit is an active measuring instrument (such as an eddy current displacement sensor) installed on the machine tool. Its probe can measure the machining dimensions of the workpiece in online contact or non-contact, such as the inner diameter or groove diameter being machined. The dimensional deviation detection unit periodically samples the dimensions of the workpiece being machined (such as the groove diameter or inner diameter) and sends the data to the controller. The controller analyzes data from multiple consecutive sampling points (e.g., 5 points) to determine whether the dimensional deviation shows a continuously increasing trend. For example, if the inner diameter of the product to be processed is 29mm before processing and it needs to be ground to 30mm within 10 seconds, and the workpiece size is tested once per second, the controller will automatically calculate the dimensions after each second after processing begins: 29.1mm, 29.2mm, 29.3mm, 29.4mm, 29.5mm, 29.6mm, 29.7mm, 29.8mm, 29.9mm, and 30.0mm. If the dimension after the first second is 29.05mm, it means the dimensional deviation is small; if the dimension after the first second is 29.15mm, it means the dimensional deviation is large.

[0045] The speed feedback unit consists of encoders mounted on the grinding wheel spindle and the workpiece shaft, respectively, used to collect the actual speed of both in real time.

[0046] The human-computer interaction unit is an operation panel with a touch screen.

[0047] The controller is a programmable logic controller (PLC), which is electrically connected to all the above units through digital / analog input / output modules and fieldbus.

[0048] The controller accesses a built-in process parameter database. This database stores process parameters corresponding to different workpiece models, such as initial spindle speed, initial workpiece axis speed, first preset threshold (i.e., lower limit of linear velocity), second preset threshold (i.e., preset value of dimensional deviation), target linear velocity range, preset tolerance, and safety threshold.

[0049] The controller's control program enables it to perform the following workflows: Parameter initialization: The operator inputs the model or key dimensions (such as groove diameter, inner diameter) of the workpiece to be processed through the human-machine interface unit. The controller then queries the process parameter database based on this information to obtain the corresponding initial spindle speed, initial workpiece axis speed, and first preset threshold V. th1 Target linear velocity V target The parameters are set, and commands are issued to make the spindle drive unit and the workpiece axis drive unit run at the initial speed.

[0050] Grinding and Real-time Monitoring: As the grinding wheel begins grinding the workpiece grooves, the controller performs the following parallel monitoring throughout the process: Current and linear velocity calculation: The real-time diameter of the grinding wheel is indirectly calculated based on the preset current-diameter model, and the current linear velocity of the grinding wheel is calculated in combination with the real-time spindle speed.

[0051] Dimensional Deviation Trend Judgment: The dimensional deviation detection unit periodically samples the dimensions (such as groove diameter or inner diameter) of the workpiece being processed and sends the data to the controller. The controller analyzes the data from multiple consecutive sampling points (e.g., 5 points) to determine whether the dimensional deviation value shows a continuously increasing trend.

[0052] Safe current monitoring: The controller continuously compares the real-time current value I with the preset safe threshold Imax in the database.

[0053] During the grinding process, the controller makes decisions based on the grinding process and real-time monitoring results: Triggering the first speed regulation mode: When the calculated real-time linear velocity V of the grinding wheel... curr Persistently below V th1 At this point, the controller determines that the grinding wheel wear is causing insufficient linear speed. Immediately, the controller sends a command to the servo driver of the workpiece axis drive unit to lock its output frequency, thus maintaining a constant workpiece axis speed. Simultaneously, the controller controls the spindle drive unit to increase its speed until V... curr Rebound to V target Nearby. This is the first speed regulation mode of "constant speed of workpiece axis - dynamic speed increase of spindle".

[0054] Triggering the second speed control mode: When the dimensional deviation reported by the dimensional deviation detection unit shows an increasing trend, the controller determines that an emergency quality anomaly has occurred. Immediately, the controller executes the second speed control mode: sending a "speed hold" command to the servo driver of the spindle drive unit; simultaneously, controlling the workpiece axis drive unit to increase its speed. This is the second speed control mode of "constant spindle speed - dynamic workpiece axis speed increase," which improves grinding uniformity by increasing the workpiece speed.

[0055] If the conditions for triggering both the first and second speed control modes are met simultaneously, the controller will prioritize the execution of the second speed control mode based on the preset conflict decision logic, in order to address the more pressing risk of dimensional deviations.

[0056] If the workpiece machining dimension deviation is less than the preset value of machining dimension deviation set in the controller, and the roundness deviation value shows an increasing trend, it will be used as one of the trigger conditions for executing the second speed regulation mode. In this case, it indicates that the machining speed is slow and the roundness does not meet the requirements. If it is not adjusted in time, the machined size will be too small, but the roundness will not meet the requirements, and the subsequent products will be scrapped because they cannot be reworked. When this problem is detected, this solution will actively adjust the grinding mode to correct it in time and reduce the scrap rate.

[0057] Throughout the grinding process, the controller synchronously executes process taboo avoidance logic. This logic reads the number Z of finished steel balls on the workpiece, pre-input via the human-machine interface unit, and calculates the actual speed ratio R between the spindle and workpiece axes in real time. The controller determines whether R is close to an integer multiple of Z (k×Z, k=1,2,3…), setting a tolerance of Δ (e.g., 0.1). If |R - k×Z| < Δ, an avoidance action is triggered: in the currently executed speed control mode, the speed of the drive unit controlled to remain constant is increased. For example, if the current speed control mode is the first mode (constant workpiece axis speed), the spindle speed is increased; if the current speed control mode is the second mode (constant spindle speed), the workpiece axis speed is increased. This operation quickly disrupts harmful speed ratios, avoiding regular vibration patterns.

[0058] Furthermore, the system monitored the real-time current I exceeding the safety threshold I throughout the grinding process. max The controller immediately sends an emergency stop signal to all drive units, and the system shuts down.

[0059] Example 2 This embodiment provides a control method for a bearing raceway variable speed grinding system, which requires the bearing raceway variable speed grinding system of Embodiment 1 above. The control method includes the following steps: S1: Parameter Initialization The human-machine interface unit inputs information about the workpiece to be processed (such as model or inner diameter) and the number of finished steel balls. The controller queries the process parameter database based on the identification information to obtain and set the initial spindle speed, initial workpiece axis speed, first preset threshold, target linear velocity range, preset tolerance, and safety threshold.

[0060] S2: Grinding Start-up and Real-time Monitoring Initiate the grinding process, rotating the spindle and workpiece axis at their initial speeds. Simultaneously, execute the following monitoring sub-steps in parallel: S2a (Current and Linear Velocity Monitoring): The operating current of the spindle motor is monitored in real time through the current sensing unit, and the real-time diameter and linear velocity of the grinding wheel are continuously calculated based on the current value and the pre-stored current-diameter model.

[0061] S2b (Dimensional Deviation Monitoring): The dimensional deviation detection unit detects the machining dimensions of the workpiece online and analyzes continuous sampling data to determine whether the dimensional deviation is increasing.

[0062] S2c (Safe Current Monitoring): Continuously compares the real-time operating current with the safe threshold obtained from the database.

[0063] S2d (Speed ​​Feedback Monitoring): The actual speed of the spindle and workpiece axis is collected in real time through the speed feedback unit.

[0064] S3: Constant linear velocity compensation This step begins with the start of grinding and runs as an independent and continuous background process in all subsequent steps, unaffected by the main process decisions. Specifically, it involves comparing the real-time grinding wheel linear velocity calculated in step S2a with the target linear velocity range, and fine-tuning the output frequency of the spindle drive unit based on the comparison result to stabilize the real-time grinding wheel linear velocity within the target range.

[0065] S4: Pattern Decision-Making and Implementation Based on the monitoring results of step S2, the controller makes decisions and executes according to the following logic: Case 1: If the real-time grinding wheel linear velocity calculated in step S2a is lower than the first preset threshold, then the first speed regulation mode is executed. Specifically, the workpiece shaft drive unit is controlled to maintain its current rotational speed constant, and the spindle drive unit is controlled to increase its rotational speed.

[0066] Scenario 2: If step S2b determines that the machining dimensional deviation is trending upwards, then the second speed regulation mode is executed. Specifically, the spindle drive unit is controlled to maintain its current constant speed, while the workpiece shaft drive unit is controlled to increase its speed. In this mode, step S3 (constant linear velocity compensation) fine-tunes the setting value of "constant spindle speed" to collaboratively stabilize the grinding wheel linear velocity.

[0067] Case 3 (Conflict Decision): If the conditions of Case 1 and Case 2 are met simultaneously, the second speed regulation mode shall be executed first.

[0068] Case 4: If step S2b determines that the machining dimension deviation is less than the preset value of machining dimension deviation set in the controller, and the roundness deviation value has an increasing trend, the above-mentioned second speed regulation mode is also executed.

[0069] S5: Process Taboos and Avoidance During any speed adjustment mode in step S4, this step is performed synchronously: The ratio of the actual spindle speed to the actual workpiece axis speed is calculated in real time; it is determined whether this ratio approaches (i.e., the difference between the two is less than the preset tolerance) an integer multiple of the number of finished steel balls; if so, the speed is adjusted to disrupt this approach. Specifically, in the currently executed speed adjustment mode, the speed of the drive unit (or axis) that is controlled to remain constant is increased. For example, the spindle speed is increased in the first speed adjustment mode, and the workpiece axis speed is increased in the second speed adjustment mode.

[0070] S6: Speed ​​Closed-Loop Correction While executing the speed regulation mode in step S4, the speed regulation command for the spindle drive unit or workpiece axis drive unit can be dynamically corrected based on the deviation between the actual speed and the target speed fed back from step S2d, so as to form a closed-loop speed control and improve the speed control accuracy.

[0071] S7: Safety Monitoring and Emergency Stop In all the above steps, if the S2c step detects that the operating current exceeds the safety threshold, it immediately sends an emergency stop command to all drive units to control the entire system to stop running.

[0072] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A bearing groove variable speed grinding system, comprising a spindle drive unit for driving the grinding wheel to rotate and a workpiece shaft drive unit for driving the workpiece to rotate, characterized in that, Also includes: A current sensing unit is used to monitor the operating current of the spindle drive unit; The dimensional deviation detection unit is used for online detection of machining dimensional deviations of workpieces; The controller is connected to the spindle drive unit, the workpiece axis drive unit, the current sensing unit, and the dimensional deviation detection unit. The controller is used for: The real-time linear velocity of the grinding wheel is calculated based on the monitoring data from the current sensing unit. During the grinding process, when the real-time grinding wheel linear speed is lower than the first preset threshold, the first speed regulation mode is executed: the workpiece shaft drive unit is controlled to maintain a constant rotation speed, and the spindle drive unit is controlled to increase the rotation speed. When the dimension deviation detection unit detects an increasing trend in the machining dimension deviation, the second speed regulation mode is executed: the spindle drive unit is controlled to maintain a constant speed, and the workpiece shaft drive unit is controlled to increase its speed.

2. The bearing raceway variable speed grinding system according to claim 1, characterized in that: The controller is also used as one of the trigger conditions for executing the second speed regulation mode when the workpiece machining dimension deviation is less than the preset value of machining dimension deviation set in the controller and the roundness deviation value shows an increasing trend.

3. The bearing raceway variable speed grinding system according to claim 2, characterized in that: The controller also includes conflict decision logic: when the real-time grinding wheel linear speed is lower than the first preset threshold, and the size deviation detection unit detects that the machining size deviation is increasing, the second speed regulation mode is executed first.

4. The bearing raceway variable speed grinding system according to claim 1, characterized in that: The controller also includes process taboo avoidance logic: Obtain the number of finished steel balls for the workpiece; During the grinding process, the ratio of the actual spindle speed to the actual workpiece spindle speed is calculated in real time. When the difference between this ratio and an integer multiple of the number of finished steel balls is less than a preset tolerance, the speed of the spindle drive unit or the workpiece spindle drive unit is adjusted so that the ratio deviates from the integer multiple. The method for adjusting the speed is as follows: in the currently executed speed regulation mode, increase the speed of the drive unit that is controlled to remain constant.

5. The bearing raceway variable speed grinding system according to claim 1, characterized in that: The controller further includes a constant linear velocity compensation module, which includes: Based on the real-time current data of the current sensing unit, the real-time diameter and real-time linear velocity of the grinding wheel are continuously calculated. By fine-tuning the output frequency of the spindle drive unit, the real-time linear velocity is maintained within the preset target linear velocity range; The constant linear speed compensation module operates continuously in the first speed regulation mode, the second speed regulation mode, and the grinding process without mode switching.

6. The bearing raceway variable speed grinding system according to claim 5, characterized in that: In the second speed regulation mode, the constant linear speed compensation module achieves constant grinding wheel linear speed by finely adjusting the "constant rotation speed" setting range value of the spindle drive unit.

7. The bearing raceway variable speed grinding system according to claim 1, characterized in that: It also includes a speed feedback unit connected to the controller, which is used to collect the actual speed of the spindle drive unit and the workpiece shaft drive unit in real time; the controller performs closed-loop speed regulation of the corresponding drive unit according to the actual speed.

8. The bearing raceway variable speed grinding system according to claim 1, characterized in that: The controller accesses a process parameter database; The process parameter database stores process parameters related to the workpiece, including at least one of the first preset threshold and the target linear velocity range.

9. A control method for a bearing raceway variable speed grinding system, characterized in that: The bearing raceway variable speed grinding system according to any one of claims 1-8 is required, and further includes the following steps: Real-time monitoring steps: During the grinding process, the operating current of the spindle motor that drives the grinding wheel is monitored in real time, and the machining dimensional deviation of the workpiece is detected online; Model Decision and Implementation Steps: Calculate the real-time linear velocity of the grinding wheel based on the operating current; If the real-time grinding wheel linear speed is lower than the first preset threshold, the first speed regulation mode is executed: the workpiece shaft speed driving the workpiece rotation is kept constant, and the speed of the spindle motor is increased; If an increasing trend in the machining dimensional deviation is detected, the second speed regulation mode is executed: the speed of the spindle motor is kept constant, while the speed of the workpiece axis is increased.

10. The control method for a bearing raceway variable speed grinding system according to claim 9, characterized in that: The pattern decision-making and execution steps also include: If the real-time grinding wheel linear speed is lower than the first preset threshold, and at the same time an increasing trend in the machining size deviation is detected, the second speed regulation mode is executed first.

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