High-precision machining process of power output gear

Abstract

The present application relates to a kind of high-precision machining process of power output gear, belong to gear machining technical field.The process obtains tooth blank entrance detection information and hot front geometry information, forms tooth blank state identification and hot front allowance distribution;According to the identification and allowance distribution, determine hot front processing parameter;In heat treatment process, collect deformation related process quantity, identify heat treatment state point and execute constraint retention, segmented unloading or back pressure;According to hot post detection information, generate single-piece correction information and batch trend correction information, to form fine grinding compensation instruction;In fine grinding, according to the state of grinding process identification state abnormal point and adjust grinding control parameter;After fine grinding, strengthen review and quality data correlation are carried out.The process can improve the consistency and process traceability of power output gear batch machining.

Description

Technical Field

[0001] This invention relates to the field of gear processing technology, and specifically to a high-precision processing technology for power output gears. Background Technology

[0002] Power output gears for large engineering machinery are typically used in power transmission components such as transfer cases, reducers, and travel transmission devices. During service, they are subjected to low-speed heavy loads, high-torque impacts, and off-center meshing. These gears generally undergo processes such as forging, normalizing or tempering, rough machining, hobbing or shaping, carburizing and quenching, tempering, grinding, strengthening, and final inspection.

[0003] In current batch processing of power output gears, differences in gear blank entry points, heat treatment deformation release status, post-heat measurement errors, grinding wheel condition, inspection temperature, and final inspection results are often recorded separately by different processes. There is a lack of unified status transmission criteria for pre-heating allowances, heat treatment constraints, fine grinding compensation, and grinding dressing, resulting in insufficient batch accuracy consistency and process traceability. Therefore, it is necessary to establish a processing technology based on gear blank status identification, heat treatment status points, single-piece and batch compensation, grinding status anomalies, and reinforcement verification. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides a high-precision machining process for power output gears.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a high-precision machining process for power output gears, comprising: Acquire entry detection information and pre-thermal geometry information of the gear blank to form a gear blank status identifier and pre-thermal allowance distribution; Determine the pre-heating machining parameters based on the blank condition markings and pre-heating allowance distribution; Collect deformation-related process quantities during heat treatment, identify heat treatment state points, and execute heat treatment constraint control; Based on the post-heat inspection information, single-piece correction information and batch trend correction information are generated to obtain the fine grinding compensation instruction; Identify abnormal points in the grinding process and adjust grinding control parameters accordingly; After fine grinding, the data is checked and the process data is associated with the unique identifier of the gear.

[0006] In a preferred embodiment, forming a gear blank status identifier includes: collecting gear blank entry inspection information, which includes at least two of the following: material batch, forging direction, grain size, banded structure grade, flaw detection grade, pre-hardness distribution, initial allowance eccentricity, and hub stiffness information; and converting the collected results into an entry status record that can be accessed by pre-heat processing, heat treatment, fine grinding, and quality traceability.

[0007] In a preferred embodiment, the blank status identifier includes at least two of the following: material response factor, forging direction factor, pre-hardening factor, deformation sensitivity factor, allowance grade factor, and hub stiffness factor; wherein, the deformation sensitivity factor is determined based on at least two of the following: initial allowance eccentricity, pre-hardening fluctuation, banded structure grade, and hub stiffness information, and the corresponding input source and sampling location are retained.

[0008] In a preferred embodiment, forming the pre-heating allowance distribution and determining the pre-heating machining parameters includes: establishing a unified machining datum based on the inner hole, end face, outer circle and hub transition area; obtaining allowance data distributed along the tooth width direction, circumferential direction and radial direction; and determining the roughing allowance, semi-finishing allowance, hobbing or shaping allowance, tooth root fillet allowance and tooth direction pre-correction allowance based on the tooth blank status identification and allowance data.

[0009] In a preferred embodiment, when there is a sudden change in the allowance at the end of the tooth width, local eccentricity of the allowance on the circumference, excessively rapid change in the allowance in the hub transition zone, or fluctuations in pre-hardness exceeding the corresponding process threshold, the pre-heat allowance in the corresponding area is increased, the local unilateral cutting amount is limited, and the corresponding tooth blank is allocated to the furnace loading area that meets the requirements of furnace temperature uniformity.

[0010] In a preferred embodiment, identifying the heat treatment state point and performing heat treatment constraint control includes: using at least two of the following as deformation-related process quantities—pressure quenching displacement, fixture load, and workpiece surface temperature—to obtain the displacement change trend and load change trend; when the displacement change changes from rapid change to stable change, and the load change enters a preset range, the corresponding moment is determined as the heat treatment state point.

[0011] In a preferred embodiment, the heat treatment constraint control includes: maintaining the pressure quench constraint for a set period of time after the heat treatment state point, and then releasing the fixture according to at least two load intervals; for gear blanks with a high degree of deformation sensitivity, performing a short-term back pressure before releasing the fixture, so that the deformation release of the end face, inner hole and gear ring is under control.

[0012] In a preferred embodiment, obtaining the fine grinding compensation instruction includes: converting at least two of the following parameters into single-piece correction information: tooth profile deviation, tooth direction deviation, tooth pitch deviation, end face runout, inner hole roundness, and gear ring radial runout; converting the average error trend of gears from the same furnace or batch into batch trend correction information; and then combining the grinding wheel condition correction information and the detection temperature correction information to form the fine grinding compensation instruction.

[0013] In a preferred embodiment, identifying abnormal points in the grinding process and adjusting grinding control parameters includes: establishing reference intervals for at least two types of state quantities among grinding wheel spindle power, acoustic emission energy, tooth surface temperature rise, grinding vibration, and online tooth profile deviation; when at least two types of state quantities continuously deviate from the corresponding reference intervals, it is determined to be abnormal and a review is triggered.

[0014] In a preferred embodiment, the anomaly includes wheel passivation, insufficient cooling, or abnormal clamping vibration, and the trigger verification includes triggering wheel dressing, feed unloading, cooling flow adjustment, or clamp status verification.

[0015] The technical effects and advantages provided by the present invention in the above technical solution are as follows: Compared to methods that only process according to material grade and fixed allowance, this invention first obtains the entry inspection information and pre-heating geometry of the gear blank, then forms the gear blank state identifier and pre-heating allowance distribution, and determines the pre-heating processing parameters accordingly. Because pre-hardness fluctuations, allowance eccentricity, forging direction, and hub stiffness differences are incorporated into the processing path selection during the pre-heating stage, the pre-heating cutting amount, allowance, and furnace loading recommendations can correspond to the state of a single gear blank, which helps reduce the risks of insufficient allowance, allowance misalignment, and concentrated local deformation after heat treatment.

[0016] Compared to methods that perform pressure quenching and holding or single unloading at fixed intervals, this invention collects deformation-related process quantities during heat treatment, identifies the heat treatment state point where the gear transitions from rapid deformation release to relatively stable deformation, and performs constraint holding, segmented unloading, or short-term backpressure after this state point. Because the constraint action corresponds to the actual deformation release state, the release process of the end face, inner hole, and gear ring is smoother, and the post-heating error is more easily kept within the range that can be corrected by fine grinding, thus providing a more stable allowance basis for subsequent compensation machining.

[0017] Compared to methods that only correct errors based on the current part's post-heat inspection results, this invention generates single-part correction information for the current part's error and batch-wide trend correction information for stable deviations within the same furnace or batch. This information is then combined with the grinding wheel condition and inspection temperature to generate fine grinding compensation commands. During the fine grinding process, abnormal conditions are identified based on spindle power, acoustic emission, tooth surface temperature rise, vibration, or online tooth profile deviation, triggering adjustments such as dressing, load reduction, or cooling. This allows for process intervention before final inspection and enables the quality data to be reused for subsequent batch parameter presets. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0019] Figure 1 This is a schematic diagram of the overall process for high-precision machining of the power output gear of the present invention.

[0020] Figure 2 This is a schematic diagram illustrating the application scenario of the power output gear processing of the present invention.

[0021] Figure 3 This is a schematic diagram showing the relationship between the blank state identification and the preheating allowance distribution of the present invention.

[0022] Figure 4 This is a schematic diagram of the heat treatment state point identification and constraint control logic of the present invention.

[0023] Figure 5 This is a schematic diagram illustrating the logic for generating single-item correction information and batch trend correction information in this invention.

[0024] Figure 6 This is a schematic diagram illustrating the identification and adaptive adjustment of abnormal grinding conditions according to the present invention.

[0025] Figure 7 This is a schematic diagram of the tooth surface modification of the power output gear of the present invention. Detailed Implementation

[0026] The technical solution of the present invention will be further described below with reference to the embodiments. The following embodiments are used to explain the coordination relationship between the gear blank entry state, preheating allowance, heat treatment state point, fine grinding compensation, grinding state abnormal point and quality traceability, and do not limit the material grade, gear size, heat treatment furnace type, pressure quenching fixture structure, testing equipment model or gear grinding machine model. Example 1

[0027] This embodiment takes the power output external gear of a transfer case in engineering machinery as an example. The gear material can be 18CrNiMo7-6, 20CrNi2Mo, 20CrMnTiH, 42CrMo series steels, or alloy steels that meet the same strength and toughness requirements. The gear can be a power output gear with a large module, large tooth width, hub structure, or gear ring stiffness that is not completely consistent along the circumferential direction.

[0028] The process route includes, in sequence: blank entry inspection, pre-heating baseline establishment, pre-heating allowance measurement, pre-heating cutting parameter determination, heat treatment furnace loading and pressure quenching, heat treatment state point identification, post-heating error detection, fine grinding compensation calculation, grinding condition monitoring, tooth surface modification, strengthening treatment, post-strengthening verification, and quality data archiving. Each step is linked using a unique gear identifier as an index to avoid mixing data from the same batch.

[0029] During the gear blank entry inspection stage, the system collects information on material batch, forging direction, grain size, banded structure grade, flaw detection grade, pre-hardness distribution, initial allowance eccentricity, and hub stiffness. During the pre-heat measurement stage, the system uses the inner hole, end face, outer circle, and hub transition zone as a unified reference to convert allowance data in the tooth width direction, circumferential direction, and radial direction to the gear design coordinate system.

[0030] During the heat treatment stage, the system collects at least two types of data from the following: furnace temperature, carbon potential, workpiece surface temperature, press quenching displacement, fixture load, quenching medium temperature, and stirring intensity. For gears using press quenching, press quenching displacement and fixture load are preferentially used as state judgment data; for gears not using press quenching, workpiece temperature, clamping load, online deformation detection, or cooling state can be used as equivalent state data.

[0031] During the post-heat inspection stage, the system detects tooth profile deviation, tooth direction deviation, cumulative tooth pitch error, end face runout, inner hole roundness, gear ring radial runout, and common normal length. The system converts the error of the current part into single-part correction information and converts the stable offset of gears in the same furnace or batch into batch trend correction information. These two types of information are applied to the fine grinding of the current part and the initial compensation of subsequent parts, respectively.

[0032] During the finish grinding stage, the gear grinding machine adjusts the grinding wheel trajectory, feed reference, and profile modification curve according to the finish grinding compensation command. The system synchronously monitors the grinding wheel spindle power, acoustic emission energy, tooth surface temperature rise, grinding vibration, and online tooth profile deviation. The system only considers an abnormal state point when at least two of these state variables continuously deviate from the reference range, thus avoiding false triggering caused by noise from a single sensor. Example 2

[0033] The blank status identifier is used to convert blank entry differences into data that can be identified by subsequent processes. This identifier does not simply record the furnace batch number, but separately records material response, forging direction, pre-hardness, deformation sensitivity, allowance level, and hub stiffness. Each identifier retains the input source, sampling location, and generation time.

[0034] The material response factor is determined by the material grade, furnace batch number, chemical composition deviation, grain size, and banded structure grade. The forging direction factor is determined by the relationship between the forging streamlines and the gear axis, tooth width direction, and circumferential direction. The pre-hardening factor is determined by the average hardness at multiple points, the maximum hardness difference, the location of local hard spots, and the distribution of hardness measurement lines.

[0035] The deformation sensitivity factor is determined by at least two of the following: initial allowance eccentricity, pre-hardness fluctuation, banded structure grade, and hub stiffness information. To avoid misjudgment based on a single detection point, the system can set three levels for the same factor: "Normal," "Attention," and "Sensitive," or it can set values ​​from one to five. The higher the level, the more the gear blank needs to increase the frequency of allowance verification, control local cutting amounts, or adjust the heat treatment clamping strategy.

[0036] The hub stiffness factor is determined based on the hub thickness, web distribution, keyway location, weight reduction groove location, and transition fillet size. For gears with offset hubs, eccentric keyways, or asymmetrical webs, the hub stiffness factor is involved in the pre-heating allowance distribution and heat treatment constraint parameter determination to prevent directional deformation of the gear ring and hub after heat treatment.

[0037] After the gear blank status identifier is generated, the system writes it into the entry status record. Subsequent pre-heat processing, furnace loading area selection, pressure quenching constraints, fine grinding compensation, and quality traceability all call upon the same record. If a certain detection information is missing, the system does not directly generate a high-confidence identifier, but instead marks the item as pending verification and adopts a conservative margin and conservative constraint strategy, as shown in Table 1.

[0038] Table 1: Composition and Calling Relationship of Gear Blank Status Identifiers Example 3

[0039] Preheating allowance distribution is used to illustrate the true geometric state of the gear blank before it enters the hobbing, shaping, or heavy-duty scraping process. The system first establishes a machining datum based on the inner hole axis and end face, and then measures the outer circle profile, the hub transition zone profile, and the profile of the area to be formed. The measurement data are uniformly converted to the design coordinate system, allowing direct comparison of results obtained from different workstations.

[0040] Along the tooth width direction, the system sets sampling zones at least near the left end face, the middle, and near the right end face; along the circumferential direction, the system collects contour points at least in several angular intervals; along the radial direction, the system records the allowance difference between the theoretical contour and the actual contour. For gears with large tooth width or asymmetrical hubs, an end sampling zone can be added to detect abrupt changes in the tooth width end allowance.

[0041] When the local allowance on the circumference is consistently higher than the average allowance, the system marks the area as an eccentric region. For eccentric regions, the pre-heat machining does not directly remove the maximum allowance in one go. Instead, it adjusts the clamping datum based on the gear blank status, limits the cutting amount on one side, and adds a datum re-measurement after hobbing or shaping.

[0042] When there is a sudden change in the allowance at the tooth width end, a rapid change in the allowance in the hub transition zone, or a fluctuation in pre-hardness exceeding the process threshold, the system increases the pre-heat allowance in the corresponding area. The process threshold can be derived from the company's existing process cards, equipment capacity trial cutting results, or statistical intervals of historical batches of the same specification. For specifications processed for the first time, the company's existing safety range is used first; after continuous production, the threshold is corrected using historical records.

[0043] Pre-heat machining parameters include roughing allowance, semi-finishing allowance, hobbing or shaping allowance, root fillet allowance, tooth direction pre-correction allowance, and furnace loading area recommendations. These parameters correspond one-to-one with the blank status indicators and pre-heat machining allowance distribution to avoid situations where "entry inspection is only used for archiving, and subsequent processes are still processed according to fixed parameters." Example 4

[0044] The heat treatment state point is used to indicate the moment when the gear transitions from rapid deformation release to relatively stable deformation. For gears using a pressure quenching fixture, the system uses the pressure quenching displacement D, fixture load F, and workpiece surface temperature T as the main process quantities; for equipment with insufficient sensing conditions, at least two of D, F, and T can be selected, and the reasons for the uncollected items should be recorded.

[0045] The system first smooths the sampled data. Smoothing can be achieved using a three- to five-point moving average, or by employing a built-in filter in the device controller. After processing, the system calculates the displacement rate of change (VD) and the load rate of change (VF) per unit time. If VD decreases from a rapidly changing range to a stable range, and VF remains within a preset range for several consecutive sampling windows, the system determines the corresponding time point as the heat treatment state point.

[0046] One possible determination method is to record the peak value or the maximum value before stabilization of VD during the initial stage of quenching; when the subsequent VD is lower than this value by a certain percentage, or lower than the absolute variation limit set by the enterprise, and this state continues for no less than three sampling windows, and VF does not show a reverse abrupt change, the heat treatment state point is determined. This percentage and absolute variation limit are not used as fixed protection values, but are determined by gear specifications, fixture stiffness, and historical batch data.

[0047] Once the heat treatment state point is determined, the system performs constraint holding, segmented unloading, or short-term backpressure. Constraint holding is used to prevent premature springback in the later stages of microstructure transformation; segmented unloading is used to avoid sudden release of the end face, inner hole, and gear ring; short-term backpressure is used for gear blanks with high deformation sensitivity. If the state point determination result is significantly inconsistent with the temperature curve, the system does not unload immediately, but instead proceeds to manual confirmation or an extended holding process.

[0048] For gears that do not exhibit a clear shift in displacement, the system employs backup criteria. These backup criteria include the workpiece surface temperature entering the late stage of microstructure transformation, load changes continuously remaining below a threshold, displacement changes continuously remaining below a threshold, and the quenching medium temperature and stirring intensity remaining stable. These backup criteria are only used to improve process stability and do not replace the gear blank status identification and the judgment of key process quantities. Example 5

[0049] Post-heat treatment inspection is used to convert the actual errors after heat treatment into compensation instructions that can be executed in the fine grinding process. Inspection items include tooth profile deviation, tooth direction deviation, cumulative tooth pitch error, common normal length, end face runout, inner hole roundness, and gear ring radial runout. During inspection, the inspection temperature, clamping datum, inspection equipment number, and the inspector or inspection procedure version are recorded simultaneously.

[0050] Single-piece correction information comes from the current piece's inspection results and is mainly used to correct the current piece's fine grinding trajectory, tooth thickness feed reference, circumferential phase, and tooth profile modification curve. Batch trend correction information comes from several gears that have already been inspected in the same heat or batch and is mainly used to suppress low-frequency trends caused by differences in heat treatment heats, machine tool thermal conditions, grinding wheel wear, or fixture positioning drift.

[0051] When the system generates fine grinding compensation instructions, it does not simply add up all errors, but first distinguishes between the random error of the current part and the batch trend error. When the error of the current part is obvious but the batch trend is not obvious, the single-part correction weight is increased; when multiple consecutive parts deviate in the same direction, the batch trend correction weight is increased; when the grinding wheel is close to its dressing cycle or the online tooth profile deviation continues to increase, grinding wheel condition correction is added.

[0052] To prevent overcompensation, the system sets compensation limits. These limits can be determined based on the gear module, tooth width, post-heat-grinding allowance, gear grinding machine positioning accuracy, and the customer's accuracy level. When the calculated compensation exceeds the limit, the system does not directly perform full compensation but instead prompts for remeasurement, reclamping, pre-grinding, or manual confirmation.

[0053] If the end face runout, inner bore roundness, or radial runout of a gear suddenly exceeds the average value of the same batch, the system first checks the measurement temperature, clamping end face, calibration status of the testing equipment, and the unique identifier of the gear. Only when the retest result is consistent with the original test result will the error be included in the single-piece correction information. Example 6

[0054] Abnormal grinding conditions are used to trigger process intervention before obvious burns, cracks, local over-grinding, or tooth profile ripples appear on the tooth surface. The system establishes a reference range after the grinding wheel is freshly dressed or during the stable grinding stage. The reference range includes at least two of the following state variables: spindle power, acoustic emission energy, tooth surface temperature rise, grinding vibration, and online tooth profile deviation.

[0055] Reference intervals can be established separately based on gear specifications, grinding wheel type, coolant condition, and machine tool condition. For batch production, reference intervals can be updated using data from stable machining phases of the same specifications; for initial machining, reference intervals can be determined by trial cuts and equipment process cards. The system saves the conditions under which reference intervals are formed, avoiding the mixing of data from different grinding wheels and cooling conditions.

[0056] When the spindle power change rate increases continuously, the acoustic emission energy exceeds the reference range, and the tooth surface temperature rises synchronously, the system determines that the grinding wheel may be dull. At this time, the system prioritizes grinding wheel dressing and reduces the single radial feed rate in the next cycle.

[0057] When the spindle power does not change significantly but the tooth surface temperature rises rapidly, or when there is a concentrated temperature rise at the same tooth surface location, the system determines that the cooling is insufficient. In this case, the system prioritizes adjusting the cooling flow rate, nozzle angle, coolant pressure, or coolant filtration status.

[0058] When the grinding vibration amplitude suddenly increases and the online tooth profile deviation expands, the system determines that there may be clamping vibration, abnormal dynamic balance of the grinding wheel, or local hard spots. At this time, the system reduces the feed rate and prompts to check the fixture, dynamic balance of the grinding wheel, workpiece clamping end face, and hardness distribution after heating.

[0059] A single state variable briefly exceeding its limit does not immediately trigger a control action. The system marks it as a suspected anomaly and continues to observe a machining window; only if at least two types of state variables continue to deviate will dressing, load reduction, cooling adjustment, or fixture verification be triggered. In this way, the grinding process is transformed from fixed-cycle dressing to a combination of fixed-cycle and state-triggered actions. Example 7

[0060] Power take-off gears often endure low-speed heavy loads, periodic impacts, and assembly off-center loads during service. The profile modification parameters during the fine grinding stage should simultaneously consider both the design operating conditions and the actual deformation after heating. The system reads the design torque, speed range, impact load, lubrication method, bearing arrangement, assembly off-center load, post-heat tooth deformation, and fine grinding compensation commands, and determines the tooth surface modification parameters accordingly.

[0061] Tooth surface modification can include micro-bulging modification along the tooth direction, edge trimming at the tooth tip, transition modification at the tooth root, and end contact avoidance. If the tooth direction deviation is large after heating, the modification curve should first satisfy error correction and the safety of the grindable allowance, and then the working condition modification should be superimposed; if the tooth direction state is stable after heating, more consideration can be given to the contact imprint target. This can avoid over-grinding of the ends in pursuit of the theoretical contact imprint.

[0062] After precision grinding, the tooth surface and root can be subjected to shot peening, roller burnishing, or cryogenic stabilization treatment. The shot peening intensity, coverage, media specifications, and blasting angle should be matched with the tooth root fatigue requirements, tooth surface accuracy maintenance requirements, and the state of the material hardened layer. Roller burnishing can be used to strengthen the tooth root transition zone; cryogenic stabilization treatment can be used to reduce dimensional drift after heat treatment and grinding.

[0063] A review is conducted after strengthening. Review items include tooth profile deviation, tooth direction deviation, cumulative tooth pitch error, end face runout, tooth root fillet integrity, surface hardness, effective hardened layer depth, grinding burns, and magnetic particle inspection. If the tooth direction deviation after strengthening exceeds the process threshold compared to before strengthening, the system will prompt for minor re-grinding, local polishing, or re-evaluation of strengthening parameters.

[0064] The enhanced verification results are written back to the quality database and associated with heat treatment status points, fine grinding compensation commands, and abnormal grinding status points. If subsequent batches repeatedly exhibit tooth offset after enhancement, the system can prompt adjustments to the shot peening coverage, peening angle, or low-temperature stabilization treatment cycle. Example 8

[0065] The control device corresponding to the process of this invention can be independently deployed in the edge server of the production line, or it can be distributed among the MES system, heat treatment control system, gear grinding machine CNC system, and testing equipment. The control device includes a data acquisition module, a status recognition module, a process parameter generation module, a fine grinding compensation module, a grinding monitoring module, and a quality traceability module.

[0066] The data acquisition module obtains data from testing equipment, heat treatment equipment, gear grinding equipment, strengthening equipment, and manual input terminals. For networked devices, data is written via the communication interface; for non-networked devices, data is written via batch import or barcode scanning. The system saves the data source for subsequent traceability.

[0067] The status recognition module is used to generate gear blank status identifiers, identify heat treatment status points, and identify grinding status anomalies. This module is not limited to a single algorithm. Gear blank status identifiers can use rule mapping; heat treatment status points can use trend determination; and grinding status anomalies can use benchmark interval comparison. Different algorithms can be substituted, but the output results should be usable by subsequent modules.

[0068] The process parameter generation module generates pre-heating machining parameters, furnace loading area, pressure quenching constraint parameters, and unloading rhythm based on the blank status identifier and pre-heating allowance distribution. The fine grinding compensation module generates fine grinding compensation instructions based on the current part error, batch trend error, grinding wheel status, and detection temperature. The grinding monitoring module continuously judges the grinding wheel status, cooling status, and clamping status during machining.

[0069] The quality traceability module assigns a unique identifier to each gear. This unique identifier can be a QR code, data matrix code, RFID code, or a combination of production batch number, furnace batch number, and workpiece serial number. The quality traceability module links the gear blank status identifier, heat treatment curve, heat treatment status points, fine grinding compensation instructions, status anomaly points, reinforcement verification results, and final inspection results to the same gear.

[0070] When producing power output gears of the same specifications, materials, or equipment conditions in subsequent production, the quality traceability module provides historical references to the process parameter generation module. These historical references serve only as initial parameter suggestions and do not replace current part inspection. Current part inspection data, heat treatment process parameters, and grinding process conditions still take precedence in the final judgment.

[0071] To illustrate the process effects of this invention, this embodiment provides a method for organizing small-batch verification records. The verification object is a power output gear of the same specification, and the same testing equipment, testing benchmark, and temperature correction rule are used before and after verification. When submitting the actual application documents, the values ​​in the table should be confirmed or replaced by the applicant based on the actual test report; if the testing has not yet been completed, the items and judgment methods can be retained, while the specific values ​​can be deleted.

[0072] During verification, the control group used a process with fixed quenching holding time, fixed grinding wheel dressing interval, and compensation based only on the current part's post-heat testing value; the implementation group used blank status identification, heat treatment status points, single-piece and batch compensation, grinding status anomalies, and a strengthened verification closed loop. The number of samples in each group should not be less than six, and invalid samples caused by obvious material defects, clamping errors, or abnormal testing equipment should be removed.

[0073] The results of post-heat treatment testing show that gears using heat treatment state point retention and segmented unloading exhibit reduced dispersion in end face runout, inner bore roundness, and gear ring radial runout. This indicates that when the constraint action corresponds to the actual deformation release state, the post-heat treatment allowance is more easily kept within the range that can be corrected by fine grinding.

[0074] The final inspection results of the fine grinding show that, after the combined effect of individual piece correction and batch trend correction, the final inspection fluctuations in tooth profile, tooth direction, tooth pitch, and gear ring runout are reduced. This result does not mean that the present invention can only obtain the values ​​in the table, but rather that separating the random error of the current piece and the batch trend error is beneficial to the consistency of batch processing.

[0075] As shown in Tables 2 and 3, this invention can be used for external gears, internal gears, splined gears, helical gears, herringbone gears, and integrated gear shafts. Heat treatment methods can include carburizing and quenching, carbonitriding, induction hardening, tempering followed by nitriding, or composite heat treatment. Gear machining methods can include gear hobbing, gear shaping, high-strength scraping, profile grinding, generating grinding, or honing.

[0076] Table 2: Record of post-heating errors before and after heat treatment state point control

[0077] Table 3 Final Inspection Records Before and After Fine Grinding Compensation

[0078] The entry inspection information for gear blanks is not limited to metallographic, hardness, and flaw detection results. When more inspection conditions are available on-site, residual stress, forging flow line images, surface defect images, near-surface decarburization inspection results, and cutting test results can also be added. Any of the above information that reflects the differences in the gear blank's response during subsequent heat treatment and precision grinding can be used as input for gear blank condition identification.

[0079] The methods for obtaining pre-heating allowance distribution are not limited to coordinate measuring machines (CMMs). For production lines with fast cycle times, a combination of online probes, laser contour measurement, vision measurement, or gear measurement centers can be used. For single-piece or small-batch production, offline measurement followed by manual import can be employed. As long as the allowance distribution in the directions of inner hole, end face, outer circle, and tooth width can be established and used to determine pre-heating machining parameters, the corresponding function can be achieved.

[0080] The identification of heat treatment state points can be arranged in the heat treatment control system or in an independent edge controller. For induction hardening or nitriding after tempering without pressure quenching fixtures, the state point can be understood as a stable node reflected by temperature, deformation detection, clamping load or cooling state, and the cooling intensity, tempering rhythm or shaping timing can be adjusted accordingly.

[0081] Fine grinding compensation can be replaced according to gear type. For external gears, compensation can focus on tooth direction, tooth profile, and radial runout; for internal gears, compensation can focus on internal tooth pitch, tooth profile, and clamping datum; for splined gears or integral gear shafts, compensation can also be combined with spline coaxiality, journal runout, and end face datum. The inspection items differ for different gears, but the combination relationship between individual piece correction and batch trend correction remains consistent.

[0082] The quality data closed-loop of this invention can be connected to an enterprise's existing MES, ERP, or equipment networking platform, or it can initially run as an independent database. The database does not need to store all original waveforms, but it should at least store key records that can reproduce process decisions, including gear blank status indicators, heat treatment status points, fine grinding compensation instructions, status anomalies, and final inspection conclusions. These records can support subsequent process review, batch parameter presets, and quality responsibility traceability.

[0083] The above embodiments are merely specific descriptions of the present invention. Those skilled in the art can adjust the sequence of steps, parameter thresholds, detection equipment, data structure, and control device without departing from the concept of the present invention. As long as the combination of blank state identification, heat treatment state points, single-piece and batch compensation, grinding state anomaly points, and quality data closed-loop is still used, it should be considered to fall within the protection scope of the present invention.

[0084] The sequence of steps in the above embodiments can be adjusted appropriately according to the on-site control cycle and communication delay. For example, sensor fusion can run continuously during the pre-task inspection, positioning protection can work continuously between the navigation step and the gripper action step, and persistent writing can be performed after the coordinate relationship update is confirmed. The above adjustments do not change the correspondence between task information, mode information, operation configuration, fusion environment data and protection measures.

Claims

1. A high-precision machining process for a power output gear, characterized in that, include: Acquire entry detection information and pre-thermal geometry information of the gear blank to form a gear blank status identifier and pre-thermal allowance distribution; The pre-heat machining parameters are determined based on the blank state identifier and the pre-heat machining allowance distribution; Collect deformation-related process quantities during heat treatment, identify heat treatment state points, and execute heat treatment constraint control; Based on the post-heat inspection information, single-piece correction information and batch trend correction information are generated to obtain the fine grinding compensation instruction; Identify abnormal points in the grinding process and adjust grinding control parameters accordingly; After fine grinding, the data is checked and the process data is associated with the unique identifier of the gear.

2. The high-precision machining process for the power output gear according to claim 1, characterized in that, The process of forming a gear blank status identifier includes: collecting gear blank entry inspection information, which includes at least two of the following: material batch, forging direction, grain size, banded structure grade, flaw detection grade, pre-hardness distribution, initial allowance eccentricity, and hub stiffness information; and converting the collected results into an entry status record that can be accessed by pre-heat processing, heat treatment, fine grinding, and quality traceability.

3. The high-precision machining process for the power output gear according to claim 2, characterized in that, The blank status identifier includes at least two of the following: material response factor, forging direction factor, pre-hardening factor, deformation sensitivity factor, allowance grade factor, and hub stiffness factor; wherein, the deformation sensitivity factor is determined based on at least two of the following: initial allowance eccentricity, pre-hardening fluctuation, banded structure grade, and hub stiffness information, and the corresponding input source and sampling location are retained.

4. The high-precision machining process for the power output gear according to claim 3, characterized in that, The process of establishing the pre-heating allowance distribution and determining the pre-heating machining parameters includes: establishing a unified machining datum based on the inner hole, end face, outer circle, and hub transition area; obtaining allowance data distributed along the tooth width direction, circumferential direction, and radial direction; and determining the roughing allowance, semi-finishing allowance, hobbing or shaping allowance, tooth root fillet allowance, and tooth direction pre-correction allowance based on the tooth blank status identification and allowance data.

5. The high-precision machining process for the power output gear according to claim 4, characterized in that, When there is a sudden change in the allowance at the end of the tooth width, local eccentricity of the allowance on the circumference, excessive change in the allowance in the hub transition zone, or fluctuation in pre-hardness exceeding the corresponding process threshold, the pre-heat allowance in the corresponding area is increased, the local unilateral cutting amount is limited, and the corresponding tooth blank is allocated to the furnace loading area that meets the requirements of furnace temperature uniformity.

6. The high-precision machining process for the power output gear according to any one of claims 1 to 5, characterized in that, Identifying heat treatment state points and implementing heat treatment constraint control includes: using at least two of the following as deformation-related process quantities: pressure quenching displacement, fixture load, and workpiece surface temperature, to obtain displacement change trends and load change trends; when the displacement change changes from rapid change to stable change, and the load change enters a preset range, the corresponding moment is determined as the heat treatment state point.

7. The high-precision machining process for the power output gear according to claim 6, characterized in that, The heat treatment constraint control includes: maintaining the pressure quench constraint for a set period of time after the heat treatment state point, and then releasing the fixture according to at least two load intervals; for gear blanks with a high degree of deformation sensitivity, performing short-term back pressure before releasing the fixture, so that the deformation release of the end face, inner hole and gear ring is under control.

8. The high-precision machining process for the power output gear according to any one of claims 1 to 5, characterized in that, The fine grinding compensation instruction includes: converting at least two of the following into single-piece correction information: tooth profile deviation, tooth direction deviation, tooth pitch deviation, end face runout, inner hole roundness, and gear ring radial runout; converting the average error trend of gears in the same furnace or batch into batch trend correction information; and then combining the grinding wheel condition correction information and the detection temperature correction information to form the fine grinding compensation instruction.

9. The high-precision machining process for the power output gear according to claim 8, characterized in that, Identifying abnormal points in the grinding process and adjusting grinding control parameters includes: establishing reference intervals for at least two types of state quantities among grinding wheel spindle power, acoustic emission energy, tooth surface temperature rise, grinding vibration, and online tooth profile deviation; when at least two types of state quantities continuously deviate from the corresponding reference intervals, they are judged as abnormal and a review is triggered.

10. The high-precision machining process for the power output gear according to claim 9, characterized in that, The abnormalities include wheel passivation, insufficient cooling, or abnormal clamping vibration. Trigger verification includes triggering wheel dressing, feed unloading, cooling flow adjustment, or clamp status verification.

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