A data processing method and system for tracing and analyzing the machining geometric precision of a numerical control gear hobbing machine

Abstract

The application discloses a data processing method and system for tracing analysis of machining geometric precision of a numerical control gear rolling machine, and relates to the technical field of precision detection and error tracing of the numerical control gear rolling machine. In view of the problems of mutual coupling of multi-source geometric errors, insufficient tracing positioning precision in the existing fixed counterweight detection mode, and high hardware improvement cost and poor engineering landing property of the existing improved scheme, the counterweight system is split into self-weight balance and cutting force compensation units which can be independently regulated and controlled, first error decoupling is completed through a positive and negative step counterweight sequence under no load, second error decoupling is completed through switching of a load component counterweight sequence, multiple independent error components are separated and corresponding error sources are mapped, and a counterweight dynamic operation sequence is generated by matching a machining process. The application is completely realized by relying on existing mature technologies, does not need to add hardware and complex algorithms, can realize high-precision geometric error tracing, and synchronously outputs a process optimization strategy which can be directly landed.

Description

Technical Field

[0001] This invention relates to the field of CNC gear hobbing machining accuracy detection and error tracing technology, and in particular to a data processing method and system for tracing and analyzing geometric accuracy of CNC gear hobbing. Background Technology

[0002] CNC gear hobbing machines are core equipment in gear machining, and their geometric accuracy directly determines key accuracy indicators such as tooth profile, tooth direction, and tooth pitch of the machined gear. In existing technologies, the geometric accuracy traceability of gear hobbing machines generally adopts a single-shot accuracy testing mode under fixed counterweight conditions, and infers possible error sources from the test data. However, this mode has significant technical limitations.

[0003] On the one hand, machine tool geometric accuracy errors are the result of multi-source error coupling, including inherent manufacturing and assembly errors of the guide rails and spindles, deformation errors caused by the weight of moving parts and cutting forces, and clearance and hysteresis errors of the counterweight system itself. Test data under a single fixed counterweight condition cannot effectively separate the various error components, resulting in insufficient accuracy in error tracing and making it difficult to guide targeted precision adjustments and fault location.

[0004] On the other hand, existing counterweight systems are only used as passive error compensation components, balancing the weight of moving parts with a fixed counterweight value throughout the process. Their function is singular and they are not utilized as controllable variables for active error calibration and decoupling. At the same time, the fixed counterweight mode cannot adapt to the load changes in each stage of gear hobbing, including entry, roughing, finishing, and exit. It is prone to additional deformation and vibration when switching working conditions, further increasing the difficulty of error tracing.

[0005] To address the aforementioned issues, existing improvement solutions primarily focus on adding high-precision detection hardware such as laser interferometers and force sensors, or employing artificial intelligence algorithms for error identification. The former involves high modification costs and significant on-site implementation difficulties, making it challenging to promote in existing machine tools; the latter relies on a large number of training samples, lacks robustness, and the black-box nature of the algorithms results in a lack of clear physical meaning in the traceability results, failing to support engineering-level precision adjustments. Other solutions achieve dynamic compensation by improving the counterweight structure, but this requires modifications to the machine tool itself, also resulting in high costs and long development cycles.

[0006] In summary, there is an urgent need for a technical solution that can achieve multi-source error decoupling and accurate source tracing without adding new hardware or relying on complex algorithms, but only by combining and reconstructing existing mature technologies. Summary of the Invention

[0007] To address the aforementioned issues, this application provides a data processing method and system for tracing and analyzing the geometric accuracy of CNC gear hobbing machines. This solves the problems of existing CNC gear hobbing machine accuracy tracing methods relying on single-time testing with fixed counterweights and the inability to effectively decouple the coupling of multiple geometric errors, leading to fuzzy error tracing and inaccurate fault location.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for processing data for tracing the geometric accuracy of CNC gear hobbing machining, comprising the following steps:

[0009] S1 Calibration Preparations

[0010] The counterweight system of the CNC gear hobbing machine is logically divided into an independently adjustable self-balancing counterweight unit and a cutting force compensation counterweight unit. The self-balancing counterweight unit is used to balance the weight of moving parts such as the tool holder and slide, while the cutting force compensation counterweight unit is used to offset the additional load generated by the cutting force during machining. Multiple loading levels are set for both types of counterweight units according to their rated values. Simultaneously, the geometric accuracy items of the machine tool and the workpiece to be tested are determined, and a unified reference measurement position is established.

[0011] S2 Unloaded Positive and Negative Stepped Counterweight Sequence Detection and First-Level Error Decoupling

[0012] Under no-load and no-cutting conditions, position each motion axis of the machine tool to the reference measurement position. First, execute the forward progressive loading sequence: starting from 0 counterweight, load step by step according to preset levels to the rated total counterweight. After each level of counterweight loading is completed and the machine tool deformation stabilizes, collect the detection data of all machine tool geometric accuracy items to obtain the forward loading dataset. Then, execute the reverse progressive unloading sequence: starting from the rated total counterweight, unload step by step according to preset levels to 0 counterweight. After each level of counterweight unloading is completed and stabilized, collect the detection data of the same machine tool geometric accuracy items at the same reference measurement position to obtain the reverse unloading dataset.

[0013] Linear fitting calculations were performed on the forward loading dataset, using the counterweight loading level as the independent variable and the geometric accuracy detection value of the corresponding gear as the dependent variable in a univariate linear regression. The intercept of the fitted line represents the inherent geometric error component of the machine tool, reflecting the manufacturing and assembly accuracy of the machine tool when unaffected by gravity. The slope of the fitted line represents the gravity-induced deformation error component corresponding to a unit change in counterweight, reflecting the structural stiffness characteristics of the machine tool. By comparing the difference in detection data of the same gear between the forward loading dataset and the reverse unloading dataset, the hysteresis clearance error component of the counterweight system was obtained, corresponding to the mechanical friction hysteresis, hydraulic internal leakage, or fit clearance error of the counterweight system.

[0014] S3 Load Component Counterweight Sequence Switching Detection and Secondary Error Decoupling

[0015] At least one set of typical cutting conditions was selected, and trial cutting tests were performed for each set of conditions using two different counterweight loading sequences. The first loading sequence involved first loading the self-weight balancing counterweight to its rated value, then loading the cutting force compensation counterweight to the corresponding gear position for that condition. After completing the trial cut, the geometric accuracy data of the workpiece gear was collected to obtain the first accuracy dataset. The second loading sequence involved first loading the cutting force compensation counterweight to the corresponding gear position for that condition, then loading the self-weight balancing counterweight to its rated value. After completing the trial cut, the same workpiece geometric accuracy data was collected to obtain the second accuracy dataset.

[0016] By comparing the difference between the first and second precision datasets, the sequence-sensitive error components of the counterweight system are separated, corresponding to the directional error of the counterweight guide rail clearance and the difference error of the hydraulic cylinder friction direction. Subtracting the gravity-induced deformation error components obtained in step S2 from the two precision datasets, the cutting force-induced process deformation error components are separated, corresponding to the cutting force deformation of the tool holder system, the axial cutting force deformation of the worktable, and the force deformation error of the indexing worm gear pair.

[0017] S4 Source Mapping and Optimized Output

[0018] The various error components obtained from the separation are mapped to a preset set of machine tool error sources to generate a geometric accuracy traceability analysis report, clarifying the contribution ratio of each error source to the total accuracy error. At the same time, based on the influence weight of each error component on machining accuracy, the entry, roughing, semi-finishing, finishing, and exit stages of gear hobbing are matched to generate a dynamic operation sequence of counterweights, which is then output to the CNC system for execution.

[0019] Further, in step S1, the multi-level loading gears are set to 5 levels according to 0%, 25%, 50%, 75%, and 100% of the corresponding counterweight rating; the machine tool geometric accuracy items include guide rail straightness, spindle radial runout, spindle axial runout, worktable end face runout, and indexing positioning error; the workpiece geometric accuracy items include tooth direction error, cumulative tooth pitch error, tooth profile error, and radial runout.

[0020] Furthermore, in step S3, typical cutting conditions include roughing, semi-finishing, and finishing; the cutting force compensation counterweight gear corresponding to each condition is calculated based on the axial component of the rated cutting force for that condition.

[0021] Furthermore, in step S4, the specific dynamic operation sequence of the counterweight is as follows: during the cutting stage, the counterweight is loaded to a preset level lower than the rated total counterweight to reduce the fluctuation of the tool post feed force; during the roughing stage, the self-weight balancing counterweight and the cutting force compensation counterweight are simultaneously loaded to the full value of the corresponding working condition to balance the maximum cutting load; during the semi-finishing stage, the rated value of the self-weight balancing counterweight is maintained, and the cutting force compensation counterweight level is reduced; during the finishing stage, the cutting force compensation counterweight level is further reduced to suppress the vibration transmission of the counterweight system; during the cutting-out stage, the counterweight is unloaded step by step to avoid tool retraction impact deformation.

[0022] A data processing system for tracing and analyzing the geometric accuracy of CNC gear hobbing machines, characterized in that it includes:

[0023] The counterweight condition control module is used to divide the gear hobbing machine counterweight system into a self-weight balancing counterweight unit and a cutting force compensation counterweight unit, which are set with multiple loading levels respectively, and output counterweight loading and unloading control commands according to preset positive and negative step sequences, component sequence switching sequences, and process dynamic sequences.

[0024] The multi-source data acquisition module receives the working condition trigger signal output by the counterweight working condition control module. It is used to collect machine tool geometric accuracy detection data under no-load conditions and workpiece gear geometric accuracy detection data under trial cutting conditions, and stores them according to the counterweight working condition.

[0025] The error decoupling calculation module receives datasets from the multi-source data acquisition module and performs linear fitting and differential calculations on the unloaded positive and negative stepped counterweight datasets to separate the machine tool's inherent geometric error components, gravity-induced deformation error components, and counterweight system hysteresis clearance error components; it also performs differential comparison and error subtraction on the load component sequential switching datasets to separate the counterweight system sequential sensitive error components and cutting force-induced process deformation error components.

[0026] The traceability mapping output module receives various error components output by the error decoupling calculation module, and maps each error component to a preset set of error sources to generate a traceability analysis report and matches the processing steps to generate a dynamic operation sequence for counterweight.

[0027] The CNC system adapter module receives the counterweight dynamic operation sequence output by the traceability mapping output module, and converts the counterweight dynamic operation sequence into control commands that the CNC system can recognize, and sends them to the gear hobbing machine for execution.

[0028] One or more technical solutions provided in this application embodiment have at least the following technical effects or advantages compared with the prior art:

[0029] 1. First-level decoupling is achieved through an unloaded positive and negative ladder sequence, and second-level decoupling is achieved through sequential switching of load components. Five independent error components can be separated, which solves the technical problems of multi-source error coupling and fuzzy source tracing under traditional single-condition detection. It can accurately locate the contribution ratio of each error source.

[0030] 2. It relies entirely on the original counterweight system, built-in detection device and classical numerical calculation method of the gear hobbing machine. Innovation is achieved only by reconstructing and combining the operation sequence. There is no need to modify the machine tool structure or add new sensors and detection equipment. The modification cost is extremely low and it can be directly applied to existing machine tools.

[0031] 3. Breaking away from the traditional perception that counterweights are merely passive compensation components, the counterweight system is transformed into a controllable variable for active error calibration. By designing differentiated loading sequences and working condition sequences to create controllable boundary conditions, a completely new path is provided for tracing the geometric accuracy of machine tools.

[0032] 4. It not only completes the location analysis of error sources, but also outputs a dynamic operation sequence of counterweights that is adapted to the entire processing process. It can be directly embedded into existing processing programs to improve the actual processing geometric accuracy without changing other process parameters, making it highly practical for engineering applications.

[0033] 5. The overall design adopts a modular approach, which can be connected to the existing PLC and CNC system of different models of CNC gear hobbing machines. The algorithm logic is simple and reliable, with low requirements for the on-site environment, making it suitable for batch applications in various gear processing workshops.

[0034] Other advantages, objectives and features of the invention will be set forth in the following description and will be apparent to those skilled in the art upon examination of the following description, or may be learned from practice of the invention. Attached Figure Description

[0035] Figure 1 This is a flowchart of the CNC gear hobbing machining geometric accuracy traceability analysis data processing method of the present invention;

[0036] Figure 2 This is a timing diagram of the unloaded positive and negative stepped counterweight detection operation of the present invention;

[0037] Figure 3 This is a flowchart of the sequential switching test cutting detection comparison of the counterweight unit of the present invention;

[0038] Figure 4 This is a timing diagram of the dynamic operation sequence of weight adjustment for each process in the gear hobbing process of the present invention. Detailed Implementation

[0039] 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.

[0040] It should be noted that the terms "vertical," "horizontal," "up," "down," "left," "right," and similar expressions used in this article are for illustrative purposes only and do not represent the only possible implementation.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to limit the invention; the term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0042] The following is in conjunction with the appendix Figure 1-4 The invention will be further illustrated by the illustrations and specific embodiments shown.

[0043] This embodiment uses a certain model of vertical CNC gear hobbing machine as the application object. The original hydraulic counterweight system of this machine tool has a rated total counterweight corresponding to 105% of the weight of the tool post slide. The machine tool is equipped with a grating ruler, spindle encoder and indexing encoder, and has basic position detection capabilities.

[0044] Step 1: Preparations before calibration

[0045] The existing counterweight system of the machine tool is logically decomposed into a self-weight balancing counterweight unit and a cutting force compensation counterweight unit. The rated value of the self-weight balancing counterweight corresponds to the total self-weight of the tool post slide and is used to balance the static self-weight of moving parts. The rated value of the cutting force compensation counterweight corresponds to the axial component of the machine tool's maximum cutting force and is used to offset the dynamic cutting load during machining. Both types of counterweight units are set with five loading levels: 0%, 25%, 50%, 75%, and 100%, which can be independently controlled by the machine tool's existing PLC.

[0046] Determine the inspection items and reference positions: Machine tool geometric accuracy items include X-axis guide rail straightness, Z-axis guide rail straightness, hob spindle radial runout, hob spindle axial runout, table end face runout, and indexing worm gear pair positioning error; workpiece geometric accuracy items include tooth direction error, cumulative total tooth pitch deviation, tooth profile error, and gear ring radial runout. The reference measurement positions are set as the table rotation center and the midpoint of the tool post slide stroke.

[0047] Step 2: Decoupling of unloaded positive and negative stepped counterweight sequence detection and first-level error.

[0048] The machine tool is in an unloaded, non-cutting state, with each motion axis positioned at the reference measurement position, and the spindle and worktable stationary. First, a forward progressive loading sequence is executed: starting from 0% of the total counterweight, loading is performed sequentially to 25%, 50%, 75%, and 100% of the rated total counterweight. After each loading stage, a 3-second wait is allowed for the machine tool to stabilize due to elastic deformation. All geometric accuracy data are collected using the machine tool's built-in linear scale and encoder, resulting in the forward loading datasets D0, D1, D2, D3, and D4. Then, a reverse progressive unloading sequence is executed: starting from 100% of the rated total counterweight, unloading is performed sequentially to 75%, 50%, 25%, and 0% of the total counterweight. After each unloading stage, a 3-second wait is allowed for stabilization. Data of the same accuracy are collected at the same reference position, resulting in the reverse unloading datasets D4', D3', D2', D1', and D0'.

[0049] A univariate linear regression was performed on the forward loading dataset to obtain the fitted equation y = kx + b. Here, the intercept b represents the machine tool's inherent geometric error component, which is independent of the gravity load and entirely determined by the guide rail manufacturing precision, spindle assembly quality, and the inherent precision of the indexing worm gear pair. The slope k represents the gravity-induced deformation error component corresponding to a unit change in counterweight, reflecting the machine tool's structural stiffness characteristics; a larger slope indicates weaker structural stiffness. The difference ΔD between the reverse and forward data at the same gear was calculated. n =D n '-D n This difference is the hysteresis clearance error component of the counterweight system, which corresponds to error sources such as internal leakage of the hydraulic counterweight, frictional hysteresis of the counterweight guide rail, and fit clearance. The larger the difference, the more significant the hysteresis characteristics of the counterweight system.

[0050] Step 3: Load component counterweight sequence switching detection and secondary error decoupling

[0051] Three typical cutting conditions—roughing, semi-finishing, and finishing—were selected, with corresponding cutting force compensation weights of 100%, 50%, and 25% of their rated values, respectively. For each condition, two loading sequences were used for trial cutting tests, with the workpieces and machining parameters being completely identical. Sequence A: First, the self-weight balancing weight was loaded to 100% of its rated value, then the cutting force compensation weight was loaded to the corresponding setting. After the weight stabilized, a trial cut was performed. After machining, the workpiece's geometric accuracy was checked using a gear measuring instrument, obtaining the first accuracy dataset E_A. Sequence B: First, the cutting force compensation weight was loaded to the corresponding setting, then the self-weight balancing weight was loaded to 100% of its rated value. After the weight stabilized, a trial cut was performed with the same parameters, and the workpiece's geometric accuracy was checked, obtaining the second accuracy dataset E_B.

[0052] The difference between the two datasets, ΔE = E_A - E_B, is the sequence-sensitive error component of the counterweight system. Due to the gaps in the counterweight guide rails and the directional differences in hydraulic cylinder friction, different loading sequences will cause deviations in the final equilibrium position of the counterweight system. This type of error cannot be identified separately under the traditional fixed counterweight loading method. Subtracting the gravity-induced deformation error components obtained in step 2 from E_A and E_B respectively, the remaining amounts are the cutting force-induced process deformation error components, corresponding to the bending deformation of the tool holder caused by the cutting force, the end face deformation of the worktable caused by the axial cutting force, and the transmission error caused by the force on the indexing worm gear pair, etc.

[0053] Step 4: Source Mapping and Output Optimization

[0054] An error source mapping relationship is established: inherent geometric errors correspond to guide rail manufacturing and assembly errors, spindle assembly errors, and inherent errors of the indexing worm gear pair; gravity-induced deformation errors correspond to insufficient guide rail stiffness and insufficient spindle system stiffness; counterweight hysteresis clearance errors correspond to counterweight guide rail friction and hydraulic system leakage; counterweight sequence sensitivity errors correspond to the difference in counterweight guide rail clearance direction and hydraulic cylinder friction direction; cutting force-induced deformation errors correspond to the tool post system stiffness and worktable system stiffness. The five types of error components are substituted into the mapping relationship to generate a geometric accuracy source analysis report, clarifying the contribution ratio of each error source and guiding subsequent accuracy adjustments.

[0055] Simultaneously, a dynamic operation sequence for counterweight is generated by matching the gear hobbing process:

[0056] Cutting phase: The counterweight is loaded to 75% of the rated total counterweight to reduce the impact fluctuation when the tool holder cuts into the workpiece;

[0057] Roughing stage: 100% self-weight balancing counterweight + 100% cutting force compensation counterweight to balance the maximum cutting load;

[0058] Semi-finishing stage: 100% self-weight balancing counterweight + 50% cutting force compensation counterweight to reduce vibration transmission of the counterweight system;

[0059] Precision cutting stage: 100% self-weight balancing counterweight + 25% cutting force compensation counterweight further suppresses vibration and ensures precision machining accuracy;

[0060] Cutting stage: unload the counterweight in stages of 50%, 25%, and 0% to avoid end face tooth profile errors caused by tool retraction impact.

[0061] The counterweight operation sequence is converted into a CNC macro program, sent to the machine tool CNC system, and embedded into the existing machining process for automatic execution.

[0062] This embodiment corresponds to the CNC gear hobbing machining geometric accuracy traceability analysis data processing system of the above method, which includes five functional modules, all of which are implemented based on existing mature software and hardware module combinations.

[0063] The counterweight working condition control module is based on the machine tool's original PLC for logic configuration. It has three types of control logic built-in: forward and reverse step loading, component sequence switching, and process dynamic matching. It can automatically output counterweight loading and unloading instructions according to preset timing, without the need for additional control hardware.

[0064] The multi-source data acquisition module acquires real-time position data from the grating ruler and encoder via the machine tool's existing Profibus bus. It also reserves a standard data interface to support offline data import from external dial indicators and gear measuring instruments. All data is stored in categories according to the counterweight working condition label.

[0065] The error decoupling calculation module runs on the machine tool's host industrial computer. It uses only the classic linear regression algorithm and the difference calculation algorithm to perform first-level decoupling and second-level decoupling calculations in sequence, and outputs five types of independent error component data. The calculation process is transparent and the physical meaning is clear.

[0066] The traceability mapping output module has a built-in error source mapping table, which can automatically match error components to the corresponding machine tool structure error sources, generate a standardized traceability analysis report, and automatically generate a dynamic operation sequence of counterweights based on process characteristics.

[0067] The CNC system adapter module supports G-code macro program format output, which can directly convert the counterweight operation sequence into control code that the machine tool can recognize, embed it into the original machining program to achieve automatic operation, without changing the original machining process framework.

[0068] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A method for processing data for tracing the geometric accuracy of CNC gear hobbing machining, characterized in that, Includes the following steps: S1 calibration preparation: The counterweight system of the CNC gear hobbing machine is divided into an independently adjustable self-weight balancing counterweight unit and a cutting force compensation counterweight unit. Multiple loading levels are set for the two types of counterweight units according to the rated values. The geometric accuracy items of the machine tool and the geometric accuracy items of the workpiece to be tested are determined, and a unified reference measurement position is set. S2 No-load forward and reverse stepped counterweight sequence detection and first-level error decoupling: In the no-load, no-cutting state, each motion axis of the machine tool is positioned to the reference measurement position; first, a forward step-by-step loading sequence is executed: starting from 0 counterweight, the counterweight is loaded step-by-step according to the preset gear to the rated total counterweight. After each counterweight loading is completed and stabilized, the detection data of all machine tool geometric accuracy items are collected to obtain the forward loading dataset; then, a reverse step-by-step unloading sequence is executed: starting from the rated total counterweight, the counterweight is unloaded step-by-step according to the preset gear to 0 counterweight. After each counterweight unloading is completed and stabilized, the detection data of the same machine tool geometric accuracy items are collected at the same reference measurement position to obtain the reverse unloading dataset; linear fitting is performed on the forward loading dataset to separate the machine tool's inherent geometric error component and gravity-induced deformation error component; the difference between the detection data of the same gear in the forward loading dataset and the reverse unloading dataset is compared to separate the counterweight system hysteresis clearance error component; S3 Load Component Counterweight Sequence Switching Detection and Secondary Error Decoupling: Select at least one set of typical cutting conditions, and perform trial cutting tests with two different counterweight loading sequences for each set of conditions: The first loading sequence is to first load the self-weight balancing counterweight to the rated value, and then load the cutting force compensation counterweight to the corresponding gear for the condition. After completing the trial cutting, collect the geometric accuracy data of the workpiece gear to obtain the first accuracy dataset; The second loading sequence is to first load the cutting force compensation counterweight to the corresponding gear for the condition, and then load the self-weight balancing counterweight to the rated value. After completing the trial cutting, collect the same workpiece geometric accuracy data to obtain the second accuracy dataset; Compare the difference between the first accuracy dataset and the second accuracy dataset to separate the counterweight system sequence-sensitive error component; Subtract the gravity-induced deformation error component obtained in step S2 from the two sets of accuracy datasets to separate the cutting force-induced process deformation error component. S4 Source Mapping and Optimization Output: The various error components obtained by separation are mapped to the preset set of machine tool error sources to generate a geometric accuracy source analysis report; at the same time, according to the influence weight of each error component on the machining accuracy, the dynamic operation sequence of counterweight is generated by matching each process stage of gear hobbing and output to the CNC system for execution.

2. The data processing method for tracing and analyzing the geometric accuracy of CNC gear hobbing as described in claim 1, characterized in that, In step S1, the multi-level loading gears are set to 5 levels according to 0%, 25%, 50%, 75%, and 100% of the corresponding counterweight rating; the machine tool geometric accuracy items include guide rail straightness, spindle radial runout, spindle axial runout, worktable end face runout, and indexing positioning error; the workpiece geometric accuracy items include tooth direction error, cumulative tooth pitch error, tooth profile error, and radial runout.

3. The data processing method for tracing the geometric accuracy of CNC gear hobbing as described in claim 1, characterized in that, In step S2, the specific method for linear fitting of the forward loading dataset is as follows: using the counterweight loading level as the independent variable and the geometric accuracy detection value of the corresponding gear as the dependent variable, a univariate linear regression is performed. The intercept value of the fitted line is the machine tool's inherent geometric error component, and the slope value of the fitted line is the gravity-induced deformation error component corresponding to a unit counterweight change.

4. The data processing method for tracing the geometric accuracy of CNC gear hobbing as described in claim 3, characterized in that, In step S2, the hysteresis clearance error component of the counterweight system is specifically: the difference between the detection value of the reverse unloading sequence and the detection value of the forward loading sequence under the same counterweight gear. This difference corresponds to the mechanical friction hysteresis, hydraulic internal leakage, or fit clearance error of the counterweight system.

5. The data processing method for tracing the geometric accuracy of CNC gear hobbing as described in claim 1, characterized in that, In step S3, the typical cutting conditions include roughing, semi-finishing, and finishing; the cutting force compensation counterweight gear corresponding to each condition is calculated based on the axial component of the rated cutting force of that condition.

6. The data processing method for tracing the geometric accuracy of CNC gear hobbing as described in claim 5, characterized in that, In step S3, the sequential sensitive error component of the counterweight system corresponds to the directional error of the counterweight guide rail clearance and the difference error of the hydraulic cylinder friction direction; the cutting force induced process deformation error component corresponds to the cutting force deformation of the tool holder system, the axial cutting force deformation of the worktable, and the stress deformation error of the indexing pair.

7. The data processing method for tracing and analyzing the geometric accuracy of CNC gear hobbing as described in claim 1, characterized in that, In step S4, the preset set of machine tool error sources includes guide rail manufacturing and assembly error sources, spindle system stiffness error sources, indexing transmission pair error sources, counterweight mechanism performance error sources, and process system stress deformation error sources.

8. The data processing method for tracing the geometric accuracy of CNC gear hobbing as described in claim 1, characterized in that, In step S4, the gear hobbing process includes the following stages: entry stage, roughing stage, semi-finishing stage, finishing stage, and exit stage; the specific dynamic operation sequence of the counterweight is as follows: Cut-in phase: The counterweight is loaded to a preset level lower than the rated total counterweight to reduce the fluctuation of the tool post feed force; Roughing stage: Simultaneously apply self-weight balancing counterweight and cutting force compensation counterweight to the full value of the corresponding working condition to balance the maximum cutting load; Semi-finishing stage: Maintain the rated value of the self-weight balance counterweight and reduce the cutting force compensation counterweight setting; Precision cutting stage: Further reduce the cutting force to compensate for the counterweight setting and suppress the vibration transmission of the counterweight system; Cutting stage: Unload the counterweight in stages to avoid deformation caused by impact during tool retraction.

9. The data processing method for tracing the geometric accuracy of CNC gear hobbing as described in claim 1, characterized in that, All geometric accuracy test data came from the gear hobbing machine's built-in grating ruler, spindle encoder, and indexing encoder, as well as external dial indicators, mandrels, and gear measuring instruments.

10. A data processing system for tracing and analyzing the geometric accuracy of CNC gear hobbing, characterized in that, include: The counterweight condition control module is used to divide the gear hobbing machine counterweight system into a self-weight balancing counterweight unit and a cutting force compensation counterweight unit, and set multiple loading levels for each. It outputs counterweight loading and unloading control commands according to preset positive and negative step sequences, component sequence switching sequences, and process dynamic sequences. The multi-source data acquisition module receives the working condition trigger signal output by the counterweight working condition control module, and is used to collect machine tool geometric accuracy detection data under no-load conditions and workpiece gear geometric accuracy detection data under trial cutting conditions, and stores them according to the counterweight working condition. The error decoupling calculation module receives the dataset from the multi-source data acquisition module and performs linear fitting and difference calculation on the unloaded positive and negative stepped counterweight dataset to separate the machine tool's inherent geometric error components, gravity-induced deformation error components, and counterweight system hysteresis clearance error components. It is used to perform differential comparison and error subtraction on the load component sequential switching dataset, and separate the counterweight system sequential sensitive error component and the cutting force induced process deformation error component. The traceability mapping output module receives various error components output by the error decoupling calculation module, maps each error component to a preset set of error sources, generates a traceability analysis report, and matches the processing steps to generate a dynamic operation sequence for counterweight. The CNC system adapter module receives the counterweight dynamic operation sequence output by the traceability mapping output module, and converts the counterweight dynamic operation sequence into control commands that the CNC system can recognize, and sends them to the gear hobbing machine for execution.

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