A method and system for preventing cracking of a main oil pump rotor shaft

Abstract

This invention discloses a method and system for preventing cracking of the main oil pump rotor shaft, belonging to the field of automatic control of mechanical processing. In order to solve the problems of scattered machining processes, lack of linkage control for arc transition dimensions, shallow groove parameters, interference fit, heat treatment parameters and residual stress results in the existing rotor shaft machining, this invention achieves the technical effect of closed-loop suppression of fatigue crack risk at the root of the rotor disk by acquiring key transition zone data, unified evaluation, transition zone matching and linkage machining parameter generation.

Description

Technical Field

[0001] This invention relates to the field of automatic control in machining, and in particular to a method and system for preventing cracking of the rotor shaft of a main oil pump. Background Technology

[0002] The main oil pump rotor shaft typically undergoes multiple processes, including shoulder forming, annular shallow groove machining, wheel assembly, heat treatment, and inspection. The root of the wheel is adjacent to the shoulder arc area, annular shallow groove area, and interference fit contact edge. The geometric transition morphology, assembly contact state, machining residual stress, and heat treatment microstructure all affect the fatigue crack risk in this area.

[0003] Current processing methods often control parameters for each process separately using independent process cards. There is a lack of unified evaluation and coordinated correction among the arc transition dimensions, annular shallow groove dimensions, wheel disc interference fit, heat treatment temperature and time, and residual stress test results. When the structural strengthening state formed by a certain process does not match the material microstructure strengthening state, subsequent testing often only detects abnormal results, making it difficult to pinpoint the root cause of the risk and establish a compensation or re-inspection path in a timely manner.

[0004] Therefore, there is a need for a method and system for preventing cracking of the main oil pump rotor shaft that can overcome the shortcomings of the existing technology. Summary of the Invention

[0005] One objective of this invention is to propose a method and system for preventing cracking in the rotor shaft of a main oil pump. Addressing the problem in existing technologies where shoulder forming, wheel assembly, shallow groove machining, heat treatment, and inspection are performed in a fragmented manner, and key parameters and residual stress results lack coordinated control, this invention proposes a technical solution that collects process state data from the critical transition zone, generates geometric stress concentration results, interference contact stress results, machining residual stress results, heat treatment microstructure results, and defect risk results. Furthermore, it generates coordinated machining parameters based on the transition zone matching index, confidence interval, and risk factor labels. This invention achieves the technical effect of maintaining consistency between structural strengthening, material microstructure strengthening, and inspection release results to suppress the risk of fatigue cracking.

[0006] This invention provides a method for preventing cracking in the rotor shaft of a main oil pump, comprising: S1, collecting process state data of the rotor shaft during shoulder forming, shallow groove machining, wheel assembly, heat treatment, and inspection to form a critical transition zone dataset, the process state data including shoulder arc dimensions, shallow groove dimensions, interference fit, heat treatment data, load, hardness, residual stress, and non-destructive testing data; S2, determining a unified evaluation zone composed of the shoulder arc zone, the annular shallow groove zone, and the interference fit contact edge based on the critical transition zone dataset, and generating geometric stress concentration results, interference contact stress results, machining residual stress results, heat treatment microstructure results, and defect risk results respectively; S3, combining the geometric stress concentration results, interference fit... Contact stress results, machining residual stress results, heat treatment microstructure results, and defect risk results are input into the transition zone matching module to obtain the transition zone matching index, confidence interval, and risk cause label; S4, based on the transition zone matching index, confidence interval, and risk cause label, linkage machining parameters are generated within the preset parameter value set for arc trimming, shallow groove machining, interference fit assembly, heat treatment, and compensation treatment; S5, the corresponding process or compensation process is executed according to the linkage machining parameters, and the corresponding updated process status data, including the compensated residual stress detection data and non-destructive testing data, are collected or written. After updating the transition zone matching index, confidence interval, and defect judgment information, release results, compensation results, or re-inspection results are generated.

[0007] Optionally, S1 includes:

[0008] Using the part identification of a single main oil pump rotor shaft as an index, the following data were collected: shoulder radius, shoulder width, annular shallow groove width, annular shallow groove depth, groove bottom fillet radius, inner diameter of the wheel disc before press-fitting, outer diameter of the rotor shaft mating, press-fitting force curve, heat treatment temperature curve, holding time, cooling rate, cutting force, cutting temperature, tool wear, surface hardness, residual stress detection value, and non-destructive testing defect judgment value.

[0009] The collected values ​​are associated with the corresponding design baseline values, process allowable ranges, and detection time points to form the critical transition zone dataset.

[0010] Optionally, S2 includes:

[0011] The geometric stress concentration results are generated based on the shoulder arc radius, shoulder arc width, annular shallow groove width, annular shallow groove depth, and groove bottom fillet radius;

[0012] The interference contact stress result is generated based on the inner diameter of the wheel disc before pressing, the outer diameter of the rotor shaft fit, and the pressing force curve.

[0013] The machining residual stress results are generated based on cutting force, cutting temperature, and tool wear.

[0014] The heat treatment microstructure results are generated based on the heat treatment temperature curve, holding time, cooling rate, and surface hardness.

[0015] The defect risk result is generated based on the residual stress detection value and the non-destructive testing defect judgment value.

[0016] Optionally, S3 includes:

[0017] The structural matching sub-index is generated from the geometric stress concentration results and the interference contact stress results;

[0018] Material matching sub-indices are generated from the results of the processing residual stress and the results of the heat treatment microstructure.

[0019] The defect risk results are used to generate detection correction sub-indicators;

[0020] The structural matching sub-index, the material matching sub-index, and the detection correction sub-index are weighted and fused according to a pre-defined weight table to obtain the transition zone matching index.

[0021] The transition zone matching index is used to characterize the matching relationship between structural stress demand, residual compressive stress state and microstructure hardness state within the unified evaluation zone.

[0022] Furthermore, the confidence interval is generated based on the transition zone matching index, the repeated detection discreteness of the residual stress detection value determined by the residual stress detection data, the repeated judgment difference of the non-destructive testing defect judgment value determined by the non-destructive testing data, and the deviation between the predicted value of the processing residual stress determined by the processing residual stress result and the residual stress detection value.

[0023] The risk cause label is determined based on the geometric stress concentration result, the interference contact stress result, the machining residual stress result, the heat treatment microstructure result, the defect risk result, and the deviation of the repeated judgment difference from their respective preset qualified boundaries, and is marked as the geometric parameter cause, assembly parameter cause, residual stress cause, heat treatment parameter cause, or detection uncertainty cause.

[0024] Optionally, S4 includes:

[0025] When the non-destructive testing defect judgment value determined by the non-destructive testing data is greater than the preset defect judgment threshold, linkage processing parameters for re-inspection are generated.

[0026] When the non-destructive testing defect judgment value is not greater than the preset defect judgment threshold, the transition zone matching index is not less than the preset acceptable lower limit, and the lower boundary of the confidence interval is not less than the preset acceptable lower limit, release linkage processing parameters are generated.

[0027] When the non-destructive testing defect judgment value is not greater than the preset defect judgment threshold, and the transition zone matching index is less than the preset acceptable lower limit or the lower boundary of the confidence interval is less than the preset acceptable lower limit, the parameters to be corrected are selected from the arc trimming parameters, shallow groove machining parameters, interference fit assembly parameters, heat treatment parameters and compensation processing parameters according to the risk cause label, and compensation linkage machining parameters are generated.

[0028] Furthermore, generating the compensation linkage machining parameters includes: when the risk cause label is a geometric parameter cause, adjusting at least one of the following: shoulder radius, annular shallow groove width, annular shallow groove depth, or groove bottom fillet radius;

[0029] When the main risk factor label is assembly parameter main factor, adjust the wheel interference fit amount or the press-in force curve;

[0030] When the main risk factor label is the main factor of heat treatment parameters, adjust the heat treatment temperature, holding time, or cooling rate.

[0031] When the main risk factor label is residual stress, low plasticity rolling parameters, shot peening strengthening parameters, or ultrasonic-assisted strengthening parameters are generated.

[0032] When the risk cause label is the main cause of detection uncertainty, a detection verification sub-parameter is generated as the compensation linkage processing parameter;

[0033] Furthermore, the compensation processing parameters include the area of ​​application, tool contact pressure, feed rate, number of applications, and target residual compressive stress boundary value;

[0034] The target residual compressive stress boundary value is determined based on the design reference value in the critical transition zone dataset, the material state data determined by surface hardness and the heat treatment microstructure results, and the process allowable range.

[0035] The effective area is determined based on the residual stress detection values ​​of the shoulder arc area, annular shallow groove area, and interference fit contact edge within the unified evaluation area;

[0036] The tool contact pressure, the feed rate, and the number of operations are determined based on the difference between the transition zone matching index and the preset acceptable lower limit, and in conjunction with the target residual compressive stress boundary value.

[0037] Optionally, S5 includes:

[0038] After performing the compensation process, the residual stress detection value, non-destructive testing defect judgment value, compensation processing parameters, and at least one of the following corresponding to the compensation process: shoulder arc size, shallow groove size, interference fit, or heat treatment temperature and time, are written into the critical transition zone dataset.

[0039] Based on the written key transition zone dataset, the unified evaluation, transition zone matching, and linkage parameter generation are re-executed to update the transition zone matching index, the confidence interval, the risk factor label, and the linkage processing parameters;

[0040] The release result is generated when the updated transition zone matching index is not less than the preset acceptable lower limit, the lower boundary of the updated confidence interval is not less than the preset acceptable lower limit, and the updated non-destructive testing defect judgment value is not greater than the preset defect judgment threshold.

[0041] When the updated nondestructive testing defect judgment value is greater than the preset defect judgment threshold, the re-inspection result is generated;

[0042] The compensation result is generated when the updated nondestructive testing defect judgment value is not greater than the preset defect judgment threshold, and the updated transition zone matching index is less than the preset acceptable lower limit or the lower boundary of the updated confidence interval is less than the preset acceptable lower limit.

[0043] On the other hand, the present invention also provides a main oil pump rotor shaft anti-crack machining system, comprising:

[0044] The system includes a data acquisition module for collecting process status data and forming a critical transition zone dataset; a unified evaluation module for determining the unified evaluation zone and generating the geometric stress concentration result, the interference contact stress result, the machining residual stress result, the heat treatment microstructure result, and the defect risk result; a transition zone matching module for generating the transition zone matching index, the confidence interval, and the risk cause label; a linkage parameter generation module for generating the linkage processing parameters based on the transition zone matching index, the confidence interval, and the risk cause label; and an execution update module for executing the corresponding process or compensation process, collecting or writing updated process status data corresponding to the executed linkage processing parameters, updating the transition zone matching index, the confidence interval, and the defect judgment information, and generating the release result, the compensation result, or the re-inspection result.

[0045] The beneficial effects of this invention are:

[0046] 1. By dividing the shoulder arc area, annular shallow groove area and interference fit contact edge into a unified evaluation area, and by integrating geometric stress concentration, interference contact stress, machining residual stress, heat treatment microstructure and defect risk results, the key states in the dispersed processes can be brought into the same judgment chain.

[0047] 2. By matching the transition zone index, confidence interval, and risk factor label, linkage processing parameters are generated, which can establish parameter linkage between arc trimming, shallow groove machining, interference fit assembly, heat treatment, and compensation treatment, avoiding release judgment based solely on a single test result.

[0048] 3. By collecting or writing updated process status data after compensation, and regenerating the transition zone matching index, confidence interval and defect judgment information, the release result, compensation result and re-inspection result can be separated in a closed loop, thereby timely suppressing the risk of fatigue cracks at the root of the wheel. Attached Figure Description

[0049] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0050] Figure 1 This is a flowchart of a method for preventing cracking of the rotor shaft of a main oil pump.

[0051] Figure 2 This is a flowchart of the transition region matching process in step S3 of the present invention. Detailed Implementation

[0052] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the invention, and therefore only show the components relevant to the invention.

[0053] refer to Figures 1-2A method for preventing cracking of a main oil pump rotor shaft includes: S1, collecting process state data of the rotor shaft during shoulder forming, shallow groove machining, wheel assembly, heat treatment, and inspection to form a critical transition zone dataset. The process state data includes shoulder arc dimensions, shallow groove dimensions, interference fit, heat treatment data, load, hardness, residual stress, and non-destructive testing data; S2, determining a unified evaluation zone composed of the shoulder arc zone, annular shallow groove zone, and interference fit contact edge based on the critical transition zone dataset, and generating geometric stress concentration results, interference contact stress results, machining residual stress results, heat treatment microstructure results, and defect risk results respectively; S3, combining the geometric stress concentration results and interference contact stress results... The force results, machining residual stress results, heat treatment microstructure results, and defect risk results are input into the transition zone matching module to obtain the transition zone matching index, confidence interval, and risk cause label; S4, based on the transition zone matching index, confidence interval, and risk cause label, linkage machining parameters are generated within the preset parameter value set for arc trimming, shallow groove machining, interference fit assembly, heat treatment, and compensation treatment; S5, the corresponding process or compensation process is executed according to the linkage machining parameters, and the corresponding updated process status data, including the compensated residual stress detection data and non-destructive testing data, are collected or written. After updating the transition zone matching index, confidence interval, and defect judgment information, release results, compensation results, or re-inspection results are generated.

[0054] In this specific embodiment, S1 includes:

[0055] Part markings for a single main oil pump rotor shaft The acquisition task was established using the unique index, and the shoulder forming completion time was recorded. Annular shallow groove machining completion time During the disc pressing process Heat treatment process and final inspection time The detection time point is recorded in the same part record;

[0056] exist The radius and width of the shoulder arc were measured using a coordinate measuring machine, and the units of measurement and the measuring equipment number were recorded. The width, depth, and bottom fillet radius of the annular shallow groove were measured using a profilometer, and the corresponding probe radius and sampling step distance were recorded. The inner diameter of the wheel before pressing was measured using a pneumatic gauge, and the outer diameter of the rotor shaft was measured using an outside micrometer. Simultaneously, the pressing force curve was recorded by a force sensor built into the pressing machine at a fixed sampling period, and the curve was compared with ID and... Binding, in The heat treatment temperature curve and holding time were recorded by thermocouples inside the furnace at fixed sampling intervals. Simultaneously, the cooling rate was obtained based on the ratio of temperature drop to time within a set temperature range. Surface hardness was recorded using a hardness tester after heat treatment. During the shallow groove machining process, the cutting force is recorded by a force gauge, the cutting temperature is recorded by an infrared thermometer, and the tool wear is recorded by a tool micro-measuring system. These process data are then linked to the ID and machining step number. At the same time, the residual stress detection value is recorded at the preset measurement point coordinates of the shoulder arc area, the annular shallow groove area and the contact edge of the interference fit corresponding to the unified evaluation area using an X-ray diffraction residual stress meter, and the measurement point coordinate system definition and diffraction peak fitting parameters are saved simultaneously. At the same time, the ultrasonic testing equipment is used to perform non-destructive testing on the same unified evaluation area and output the non-destructive testing defect judgment value.

[0057] The collected process status data are written into the critical transition zone dataset according to a unified field, where the status vector of a single part at a single inspection time point is denoted as:

[0058] ;

[0059] In the formula For part identification, For the detection time point and The radius of the shoulder arc, The width of the shoulder arc. The width of the annular shallow groove, The depth of the annular shallow groove. The radius of the fillet at the bottom of the groove is 1. The inner diameter of the wheel before pressing. For the outer diameter of the rotor shaft, The indentation force curve and The time variable is the pressing process. The heat treatment temperature profile and The time variable in the heat treatment process For heat preservation time, For cooling rate, For cutting force, For cutting temperature, This refers to the amount of tool wear. For surface hardness, This represents the residual stress test value. This is the defect judgment value for non-destructive testing. This indicates transpose to form a column vector;

[0060] At the same time within the dataset Each component is written with its corresponding design baseline value and the upper and lower limits of the process allowable range. A one-to-one association is established between the design baseline value source drawing number, the process allowable range source process document number, the data acquisition equipment calibration status, and the data acquisition timestamp and the corresponding component, thus forming a data acquisition system. The key transition zone dataset is indexed, organized around detection time points, and structured using a four-element relationship: "collected value - design baseline value - process allowable range - detection time point".

[0061] In this specific embodiment, S2 includes:

[0062] The unified evaluation module reads the same part identifier from the critical transition zone dataset. corresponding to The design baseline value field and process allowable range field of the part are also included, and a unified evaluation area is constructed under the data coordinate system definition written in S1. ,in From the shoulder arc area Circular shallow trench area and the contact edge of the interference fit It is constructed by splicing the ends together, and all three are positioned with the rotor shaft axis as the reference. Covering the shoulder radius in the axial direction The corresponding arc transition range covers the rotor shaft surface radially to a depth of 1.0 mm below the design reference surface. The width of the annular shallow groove is covered in the axial direction. The corresponding slot range covers the bottom of the slot radially to a depth of 1.0 mm below the bottom, and the center position of this slot range is determined by the design datum coordinate field of the part in the dataset. The last 1.0mm edge band near the root of the wheel disc is covered in the axial direction of the contact area between the wheel disc and the rotor shaft, and the outer diameter of the contact area is covered in the radial direction. The corresponding contact surface extends to a depth of 1.0 mm below the surface, and then... The system automatically categorizes each measuring point into a preset set of measuring point coordinates. or A list of measurement points for each zone is generated to ensure that subsequent results correspond one-to-one with the unified evaluation area;

[0063] The result of geometric stress concentration is denoted as The geometric profile of the sub-model was obtained through calculation using a three-dimensional finite element sub-model, and the sub-model's geometric profile is determined by the radius of the shoulder arc. Shoulder radius width Width of the annular shallow groove Circular shallow groove depth With the radius of the bottom fillet Parameterized generation and retention of only overlays For local entities, the material parameters of the sub-model are taken as the elastic modulus. Compared with Poisson Furthermore, the element type is an eight-node hexahedral reduced integral element, and... A mesh density of 0.20 mm element side length is applied within the critical area, while a mesh density of 1.00 mm element side length is applied in the non-critical area. The boundary conditions are set to fully constrain axial displacement and rotation at one end, and apply a unit bending moment load about the axis and radial direction at the other end to form a nominal stress field. Take as Maximum equivalent stress inside and far away The ratio of the nominal equivalent stress of the reference section and the Write the result to the geometric stress concentration field;

[0064] The interference contact stress result is denoted as , Inner diameter before pressing by the wheel disc Rotor shaft mating outer diameter With the indentation force curve Generate, where first of all, with Determine whether the geometric interference of the part is within the corresponding process allowable range in the dataset and use the press-fit force curve. The end sample value defines the pressure at the end of the pressurization process. And with The maximum sampling value defines the peak pressing force. Then, the design reference value of the corresponding wheel mating length for this part is read and the friction coefficient is taken. Will Based on the contact circumference length The average contact pressure of the edge band is converted from the mating length to obtain the desired result. and will Peak pressing force and The results are jointly written into the interference contact stress field to support subsequent traceability;

[0065] The result of machining residual stress is denoted as Cutting force collected by S1 Cutting temperature With tool wear Generated using a linear prediction model with fixed parameters, and the model is:

[0066] ;

[0067] In the formula The residual stress is predicted and expressed in MPa, with negative values ​​representing residual compressive stress. For the intercept term and take Let be the cutting force coefficient and take Let be the cutting temperature coefficient and take Let be the tool wear coefficient and take The average cutting force in the stable segment of the shallow groove machining step is given, and the unit is . The average cutting temperature of the stable segment of the same step, in units of The wear amount on the flank face of the tool in the same machining step is expressed in mm, and the unit is... The start and end timestamps of the stable segment value window are written into the machining residual stress result field;

[0068] The microstructure result of heat treatment is denoted as , From the heat treatment temperature curve Insulation time Cooling rate With surface hardness Generate and solidify records in a hierarchical manner, from Extracting the highest temperature And the temperature is not lower than The cumulative duration is used as the effective duration of austenitization, and the data is read simultaneously. and The organization status level is given according to a fixed criterion, with a value of 2 indicating that the organization status level is 2. And the effective duration of austenitization is not less than 20 minutes. and An organization status level of 1 indicates that the organization status level is not met, but is met even though it is 2. and The organization status level is set to 0 to represent all other cases, and will... Austenitization effective duration The organization status level is written together with the heat treatment organization status result field.

[0069] Defect risk results are denoted as Residual stress test values Defect judgment value of non-destructive testing Generate and solidify records based on the worst-case scenario principle of a unified evaluation area, where in and Within the three partitions respectively Take the maximum value to obtain the maximum tensile stress tendency of the partition and then... The maximum value is taken to obtain the most unfavorable defect judgment for that partition. Simultaneously, the maximum value of the most unfavorable values ​​from the three partitions is taken again as the global most unfavorable value for the unified evaluation area. A defect risk level is then given according to a fixed criterion, with a defect risk level of 2 indicating... A defect risk level of 1 indicates And the most unfavorable overall evaluation area A defect risk level of 0 indicates all other cases, and will ultimately be... , and Output as a unified evaluation module and identified by part. Write back the critical transition zone dataset for use in step S3.

[0070] In this specific embodiment, S3 includes:

[0071] The transition zone matching module reads the same part identifier from the critical transition zone dataset. Corresponding geometric stress concentration results Interference contact stress results Results of machining residual stress Results of heat treatment microstructure and defect risk results The above five types of results are then uniformly converted into a range of values. The pass / fail scores are used to achieve weighted fusion, among which the pass / fail scores are used to achieve weighted fusion. Set qualified boundaries and the boundary of full marks ,when The geometric pass score is denoted as ,when hour Mapping from 1 to 0 in a linear decreasing manner, when hour ;

[0072] against Set the lower limit of the qualified range Upper limit of the qualified range and target center value ,when Falling The assembly qualification score is recorded as follows: and exist Take 1 and follow Deviation Decrease linearly to... or When 0 is taken, When it falls outside the interval ;

[0073] against Set full score boundary With qualified boundary ,when The residual stress pass rate score during machining is denoted as: ,when hour Mapping from 1 to 0 in a linear decreasing manner, when hour ;

[0074] against Take its level value Mapped to a heat treatment pass rate score at a fixed ratio ;

[0075] against Take its level value Mapped to a pass / fail score at a fixed ratio ;

[0076] In obtaining Sub-indices for structural matching are generated later. Generate material matching sub-indices Generate detection correction sub-indices And according to the pre-calibrated and fixed weight coefficients in the weight table. Perform weighted fusion to obtain the transition zone matching index Its calculation formula is In the formula The transition zone matching index has a value range of 1. For the weights of the structure matching sub-indicators, Weights for the material matching sub-index. To test the weights of the corrected sub-indicators, For structural matching sub-indicators, For material matching sub-index, To detect the correction sub-indicators;

[0077] To generate confidence intervals, the transition region matching module uses a unified evaluation region. Internal residual stress test value Perform repeated inspections and determine the defect value for non-destructive testing. Repeated judgments are performed, with residual stress detection in Three consecutive measurements were taken at each preset measurement point in the three zones, and the average values ​​were taken to form the mean sequence for that measurement point. Simultaneously, the standard deviation of the three measurements at each measurement point was calculated, and the arithmetic mean of the standard deviations of all measurement points was taken as the repeated detection discrete quantity. Non-destructive testing involves scanning twice consecutively along the same scanning path and obtaining two judgment values. and ,Will As a measure of difference in duplicate determination Simultaneously, the predicted value of residual stress during processing will be... Arithmetic mean of the residual stress measurements at all points within the unified evaluation area The absolute value of the difference As the deviation between prediction and measurement ;

[0078] Will By fixing the sensitivity coefficient Converted to the overall uncertainty of the matching index The formula for its calculation is:

[0079] ;

[0080] In the formula To match the comprehensive uncertainty of the index and the range of values ​​is , This is the sensitivity coefficient for repeatedly detecting discrete quantities to the matching index. The discrete quantity for repeated detection of residual stress. The sensitivity coefficient for repeatedly determining the difference in the matching index. To repeatedly determine the difference in non-destructive testing, The sensitivity coefficient for predicting the deviation from the measured value to the matching index. This refers to the deviation between the predicted value of residual stress and the average value of residual stress detected during processing.

[0081] The confidence interval is set at a confidence level of 1. Its lower boundary is denoted as Its upper boundary is denoted as and will and The output is the confidence interval for that part;

[0082] To generate risk principal cause labels, the transition zone matching module uses preset acceptable boundaries to determine whether each result exceeds the limit and calculates the deviation. Geometric parameter principal causes are... or As a trigger condition and relatively The excess ratio is used as the geometric deviation, and the main cause of the assembly parameters is... or As a trigger condition and The proportion of deviation relative to the nearest acceptable boundary is taken as the assembly deviation, and the main cause of residual stress is... or As a trigger condition and relatively The excess ratio is used as the residual stress deviation, and the main factor is the heat treatment parameters. or As a trigger condition and As a deviation from heat treatment, the main cause of detection uncertainty is... or As a trigger condition and As a deviation from uncertainty;

[0083] The category corresponding to the largest of the five deviations is determined as the main risk factor label and output as the main risk factor for geometric parameters, assembly parameters, residual stress, heat treatment parameters, or detection uncertainty. Confidence interval The risk factor labels are written into the critical transition zone dataset for use in step S4.

[0084] In this specific embodiment, S4 includes:

[0085] The linkage parameter generation module reads part identifiers from the critical transition zone dataset. Corresponding non-destructive testing defect judgment value Transition zone matching index Lower boundary of confidence interval Along with the risk cause label, simultaneously read the geometric stress concentration results used for parameter linkage. Interference contact stress results Predicted values ​​of residual stress during processing Heat treatment microstructure grade and unified evaluation area Residual stress test values ​​at each measuring point inside ;

[0086] Preset defect judgment threshold within the module Compared with the preset lower limit of acceptance And solidify the preset value set of arc trimming parameters. Shallow groove processing parameter preset value set , Preset value set for interference fit assembly parameters Constraint set with indentation force curve and Preset set of heat treatment parameters , The set of preset values ​​for compensation processing parameters , And among them For tool contact pressure, For tool feed rate, The number of times it is applied;

[0087] when At the same time, the linkage processing parameters for re-inspection are generated and their purpose is marked as re-inspection. Simultaneously, the detection and verification sub-parameters are solidified as being used in the unified evaluation area. Repeat the same scanning path 3 times and take the maximum value of the three judgment values ​​as the verification judgment value. Increase the ultrasonic gain by 6dB, fix the scanning step distance to 0.5mm, and return the suspicious echo position to the preset measurement point coordinate system of step S1 for positioning output.

[0088] when and and When the release linkage processing parameters are generated and their purpose is marked as release, the release linkage processing parameters specify that the part will keep the data collected and written in step S1 unchanged in subsequent processes and enter the execution update record of S5.

[0089] when and or At the same time, the linkage machining parameters for compensation are generated and their purpose is marked as compensation, while the matching gap is calculated. In the formula To determine the matching gap for the compensation strength, To preset the lower limit of acceptance, This represents the lower boundary of the confidence interval;

[0090] When the risk factor label is a geometric parameter factor, select "Reduce". The one-way rule will, within the preset value set, and At the same time, it will be promoted to the next level in its respective set and Fixed at 2.0mm, Fixed at 0.22mm, where if If it's already at 2.4mm, then maintain that position. And only The diameter is increased to 0.80mm, and the target size values ​​of arc trimming and shallow groove machining are output as compensation linkage machining parameters to drive the corresponding CNC program to call the corresponding tool compensation number and contour interpolation segment;

[0091] When the main risk factor label is assembly parameter as the main factor, Return to the assembly qualification range Adjust the geometric interference within a preset set of values ​​to achieve the target. Constrained by the indentation force curve, where when When Upgrade to the next level and Fixed as And Fixed at 32kN, when When Downgrade to the next level and maintain And Fixed at 32kN, and Corresponding inner diameter of the wheel Correction amount and rotor shaft mating outer diameter The correction amount allocation rule is fixed as "the correction amount of the inner diameter of the wheel accounts for..." Shaft outer diameter correction accounts for "Then it is output to the assembly station and the preceding finishing station;

[0092] When the main risk factor label is heat treatment parameter, the heat treatment parameter will be fixed within the preset value set. The parameter set ternary is written into the linkage processing parameters to drive the switching of heat treatment formula number, and the thermocouple sampling period is required to be consistent with step S1 to ensure that the data can be written back.

[0093] When the primary risk factor is labeled as residual stress, low-plasticity rolling compensation parameters are generated and output as a 5-tuple: "target residual compressive stress boundary value, application area, tool contact pressure, feed rate, and number of applications," where the target residual compressive stress boundary value is denoted as... And by Determined as hour ,when hour ,when hour The area of ​​effect is denoted as And all those that meet the requirements within the unified evaluation area The measuring points are constructed according to the principle of "centered on each measuring point, extending 2.0 mm axially and circumferentially". The method of merging adjacent areas to form a continuous rolling path, and the tool contact pressure Feed rate With the number of times Depend on The rule is determined and determined when Time to take ,when Time to take ,when Time to take And the start and end coordinates of the rolling path and the overlap rate per circle. The roller radius of 5mm is output along with the accompanying parameter for compensation processing to ensure that the equipment can execute it directly;

[0094] When the main risk factor label is the main cause of detection uncertainty, the generated detection verification sub-parameters are used as compensation linkage processing parameters and solidified into residual stress detection. , Each measuring point is tested repeatedly 5 times, the average value is taken, and the standard deviation is recorded. Non-destructive testing is repeated 3 times, and the maximum value is taken. The probe model and coupling method must be consistent for all three scans. These verification requirements are then combined with… Bind the output to the testing station.

[0095] In this specific embodiment, S5 includes:

[0096] The execution update module receives the linkage machining parameters output by the linkage parameter generation module and identifies them with part identifiers. Perform process dispatch and closed-loop recording, and write the purpose mark of the linkage processing parameters into the execution task sheet of the part, and limit the value of the purpose mark to release, compensation or re-inspection.

[0097] When the purpose is marked as release, the update module does not change the process status data collected and written in step S1. It only writes a release flag for the part in the critical transition zone dataset and locks the critical fields of the part as read-only to prevent subsequent accidental writing. At the same time, it binds the release flag to the release timestamp. ;

[0098] When the purpose is marked as re-inspection, the update module sends the inspection review sub-parameters to the non-destructive testing equipment and forces the same scanning path, step size and gain settings as in step S4. After the re-inspection is completed, the non-destructive testing defect judgment value obtained from the re-inspection is written into the critical transition zone dataset and the re-inspection time point is used as the new inspection time point. At the same time, the dual-value record of the original non-destructive testing defect judgment value and the re-inspection value is retained to support the update of the repeated judgment difference in the subsequent confidence interval calculation.

[0099] When the purpose is marked as compensation, the execution update module calls the corresponding compensation path according to the risk cause label and writes back the actual execution value. Specifically, when the compensation path is arc trimming or shallow groove machining, the execution update module will set the target size. and The data is sent to the CNC system and, after processing, the above dimensions are remeasured using the measuring equipment and conditions specified in step S1. The remeasured dimensions are written into the critical transition zone dataset as updated process status data, and the remeasurement time point is used as the new inspection time point.

[0100] When the compensation path is an interference fit, the update module will adjust the geometric interference. The actual pressing force curve is recorded and sent to the press-fitting machine under the constraint of the pressing force curve. The full sampling data was collected, and the inner diameter of the wheel before pressing was re-acquired. outer diameter that mates with the rotor shaft ,Will The intermediate values ​​required for the interference contact stress results generated therefrom are also written into the critical transition zone dataset;

[0101] When the compensation path is heat treatment, the update module sends the heat treatment formula parameters to the heat treatment furnace and records the heat treatment temperature curve according to the sampling period consistent with step S1. Insulation time With cooling rate After heat treatment, the surface hardness was retested. And This data is written into the critical transition zone dataset as updated process status data.

[0102] When the compensation path is low-plasticity rolling, the update module will update the effective area in the compensation processing parameters. Tool contact pressure Feed rate Number of times of action Boundary value of target residual compressive stress The data is sent to the rolling equipment and the deviation between the rolling path coordinates and the execution trajectory is recorded. After rolling is completed, the residual stress value is measured in a unified evaluation area using the same coordinate system of the measuring points as in step S1. The non-destructive testing (NDT) values ​​are obtained by performing the tests within the same uniform evaluation area. After compensation After compensation ,as well as The data is written into the critical transition zone dataset and this time point is used as the new detection time point.

[0103] When the compensation path is detection and verification, the update module collects residual stress repeated detection data and non-destructive repeated judgment data according to the number of verifications and value rules solidified in step S4, and writes the mean and standard deviation of each measuring point and the maximum value of multiple judgments into the key transition zone dataset to update the repeated detection discreteness and repeated judgment difference required for subsequent confidence intervals.

[0104] After any of the above compensation writes are completed, the update module re-triggers the unified evaluation module based on the written key transition zone dataset to generate updated geometric stress concentration results, interference contact stress results, machining residual stress results, heat treatment microstructure results, and defect risk results, and re-triggers the transition zone matching module to generate updated transition zone matching indices. Updated lower boundary of confidence interval With the updated risk cause label, the linkage parameter generation module is simultaneously triggered again to generate linkage processing parameters consistent with the updated state, thus forming a closed-loop iteration.

[0105] The update module generates a release result, compensation result, or re-inspection result based on the updated judgment value, wherein the release result satisfies the judgment formula:

[0106] ;

[0107] In the formula This is the updated non-destructive testing defect judgment value. To set the preset defect judgment threshold Matching index for the updated transition zone. This is the lower boundary of the updated confidence interval. The preset lower limit for compliance is set to 0.75. For the logical AND operator, when The re-inspection results are generated and the usage flag is switched to re-inspection to enter the re-inspection closed loop. and or The compensation result is generated and the purpose is switched to compensation to enter the compensation closed loop.

[0108] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0109] This invention incorporates the geometry, assembly, processing, heat treatment, and testing data of the critical transition zone into a single closed loop, so that parameter corrections for each process are no longer performed in isolation, but are generated and updated in a linked manner based on the transition zone matching index, confidence interval, and risk factor label.

[0110] The transition zone matching module and execution update module set up in this invention change the traditional processing structure that judges each process separately, so that the residual stress detection data, non-destructive testing data and corresponding process status data after the compensation process can be re-evaluated, thereby better supporting the release, compensation and re-inspection judgment in the crack prevention process.

Claims

1. A method for preventing cracking of a main oil pump rotor shaft, characterized in that, include: S1. Collect process status data of the rotor shaft during shoulder forming, shallow groove machining, wheel assembly, heat treatment, and inspection to form a critical transition zone dataset. The process status data includes shoulder arc dimensions, shallow groove dimensions, interference fit, heat treatment data, load, hardness, residual stress, and non-destructive testing data. S2. Based on the critical transition zone dataset, determine a unified evaluation zone consisting of the shoulder arc zone, the annular shallow groove zone, and the interference fit contact edge, and generate geometric stress concentration results, interference contact stress results, machining residual stress results, heat treatment microstructure results, and defect risk results, respectively. S3. Input the geometric stress concentration results, interference contact stress results, machining residual stress results, heat treatment microstructure results, and defect risk results into the transition zone matching module to obtain the transition zone matching index, confidence interval, and risk main cause label. S4. Based on the transition zone matching index, confidence interval, and risk cause label, generate linkage processing parameters within the preset parameter value set for arc trimming, shallow groove machining, interference fit assembly, heat treatment, and compensation treatment; S5. Execute the corresponding process or compensation process according to the linkage processing parameters, collect or write the corresponding updated process status data, including the compensated residual stress detection data and non-destructive testing data, update the transition zone matching index, confidence interval, and defect judgment information, and then generate the release result, compensation result, or re-inspection result.

2. The method for preventing cracking of the main oil pump rotor shaft according to claim 1, characterized in that, S1 includes: Using the part identification of a single main oil pump rotor shaft as an index, the following parameters are collected: shoulder radius, shoulder width, annular shallow groove width, annular shallow groove depth, groove bottom fillet radius, inner diameter of the wheel before press-fitting, outer diameter of the rotor shaft mating, press-in force curve, heat treatment temperature curve, holding time, cooling rate, cutting force, cutting temperature, tool wear, surface hardness, residual stress detection value, and non-destructive testing defect judgment value. The collected values ​​are then correlated with the corresponding design reference value, process allowable range, and detection time point to form the critical transition zone dataset.

3. The method for preventing cracking of the main oil pump rotor shaft according to claim 1, characterized in that, S2 includes: The geometric stress concentration results are generated based on the shoulder arc radius, shoulder arc width, annular shallow groove width, annular shallow groove depth, and groove bottom fillet radius; The interference contact stress result is generated based on the inner diameter of the wheel disc before pressing, the outer diameter of the rotor shaft fit, and the pressing force curve; the machining residual stress result is generated based on the cutting force, cutting temperature, and tool wear; the heat treatment microstructure result is generated based on the heat treatment temperature curve, holding time, cooling rate, and surface hardness; and the defect risk result is generated based on the residual stress detection value and the non-destructive testing defect judgment value.

4. The method for preventing cracking of the main oil pump rotor shaft according to claim 1, characterized in that, S3 includes: generating a structural matching sub-index from the geometric stress concentration results and the interference contact stress results; generating a material matching sub-index from the processing residual stress results and the heat treatment microstructure results; generating a detection correction sub-index from the defect risk results; and weighting and fusing the structural matching sub-index, the material matching sub-index, and the detection correction sub-index according to a pre-calibrated weight table to obtain the transition zone matching index; the transition zone matching index is used to characterize the matching relationship between structural stress requirements, residual compressive stress state, and microstructure hardness state within the unified evaluation zone.

5. The method for preventing cracking of the main oil pump rotor shaft according to claim 4, characterized in that, The confidence interval is generated based on the transition zone matching index, the repeated detection discreteness of the residual stress detection value determined by the residual stress detection data, the repeated judgment difference of the non-destructive testing defect judgment value determined by the non-destructive testing data, and the deviation between the predicted value of the processing residual stress determined by the processing residual stress result and the residual stress detection value. The risk cause label is determined based on the geometric stress concentration result, the interference contact stress result, the machining residual stress result, the heat treatment microstructure result, the defect risk result, and the deviation of the repeated judgment difference from their respective preset qualified boundaries, and is marked as the geometric parameter cause, assembly parameter cause, residual stress cause, heat treatment parameter cause, or detection uncertainty cause.

6. The method for preventing cracking of the main oil pump rotor shaft according to claim 1, characterized in that, S4 includes: When the non-destructive testing defect determination value determined by the non-destructive testing data is greater than the preset defect determination threshold, linkage processing parameters for re-inspection are generated; when the non-destructive testing defect determination value is not greater than the preset defect determination threshold, the transition zone matching index is not less than the preset acceptable lower limit, and the lower boundary of the confidence interval is not less than the preset acceptable lower limit, linkage processing parameters for release are generated; when the non-destructive testing defect determination value is not greater than the preset defect determination threshold, and the transition zone matching index is less than the preset acceptable lower limit or the lower boundary of the confidence interval is less than the preset acceptable lower limit, parameters to be corrected are selected from the arc trimming parameters, shallow groove processing parameters, interference fit assembly parameters, heat treatment parameters, and compensation processing parameters according to the risk cause label, and linkage processing parameters for compensation are generated.

7. The method for preventing cracking of the main oil pump rotor shaft according to claim 6, characterized in that, The generation of the compensation linkage processing parameters includes: when the main risk factor label is a geometric parameter, adjusting at least one of the following: shoulder radius, annular shallow groove width, annular shallow groove depth, or groove bottom fillet radius; when the main risk factor label is an assembly parameter, adjusting the wheel interference fit or press-fit force curve; when the main risk factor label is a heat treatment parameter, adjusting the heat treatment temperature, holding time, or cooling rate; when the main risk factor label is a residual stress, generating low-plasticity rolling parameters, shot peening strengthening parameters, or ultrasonic-assisted strengthening parameters; and when the main risk factor label is a detection uncertainty, generating detection verification sub-parameters as the compensation linkage processing parameters.

8. The method for preventing cracking of the main oil pump rotor shaft according to claim 7, characterized in that, The compensation parameters include the application area, tool contact pressure, feed rate, number of applications, and target residual compressive stress boundary value. The target residual compressive stress boundary value is determined based on the design reference value in the key transition zone dataset, material state data determined by surface hardness and the heat treatment microstructure results, and the allowable process range. The application area is determined based on the residual stress detection values ​​of the shoulder arc area, annular shallow groove area, and interference fit contact edge within the unified evaluation area. The tool contact pressure, feed rate, and number of applications are determined based on the difference between the transition zone matching index and the preset acceptable lower limit, combined with the target residual compressive stress boundary value.

9. The method for preventing cracking of the main oil pump rotor shaft according to claim 8, characterized in that, S5 includes: after performing the compensation process, writing the compensated residual stress detection value, non-destructive testing defect judgment value, compensation processing parameters, and at least one of the following corresponding to the compensation process: shoulder arc dimension, shallow groove dimension, interference fit, or heat treatment temperature and time, into the critical transition zone dataset; re-executing unified evaluation, transition zone matching, and linkage parameter generation based on the written critical transition zone dataset to update the transition zone matching index, the confidence interval, the risk cause label, and the linkage processing parameters; generating the release result when the updated transition zone matching index is not less than the preset acceptable lower limit, the lower boundary of the updated confidence interval is not less than the preset acceptable lower limit, and the updated non-destructive testing defect judgment value is not greater than the preset defect judgment threshold; generating the re-inspection result when the updated non-destructive testing defect judgment value is greater than the preset defect judgment threshold; generating the compensation result when the updated non-destructive testing defect judgment value is not greater than the preset defect judgment threshold, and the updated transition zone matching index is less than the preset acceptable lower limit or the lower boundary of the updated confidence interval is less than the preset acceptable lower limit.

10. A main oil pump rotor shaft anti-crack machining system, used to perform the main oil pump rotor shaft anti-crack machining method according to any one of claims 1 to 9, characterized in that, include: The data acquisition module is used to collect the process status data and form the key transition zone dataset; A unified evaluation module is used to determine the unified evaluation area and generate the geometric stress concentration result, the interference contact stress result, the machining residual stress result, the heat treatment microstructure result, and the defect risk result. The transition zone matching module is used to generate the transition zone matching index, the confidence interval, and the risk factor label; The linkage parameter generation module is used to generate the linkage processing parameters based on the transition zone matching index, the confidence interval, and the risk cause label; the execution update module is used to execute the corresponding process or compensation process, collect or write the updated process status data corresponding to the executed linkage processing parameters, update the transition zone matching index, the confidence interval, and the defect judgment information, and generate the release result, the compensation result, or the re-inspection result.

Images