A wear-resistant bucket tooth wear rate test method and device

Abstract

The present application relates to the technical field of engineering machinery wear-resistant material performance detection and evaluation, and particularly relates to a wear-resistant bucket tooth wear rate testing method and device, which comprises the following steps: collecting initial mass and initial profile point cloud data of a to-be-tested bucket tooth and constructing a three-dimensional space coordinate system; controlling the to-be-tested bucket tooth to perform segmented penetration wear testing, and obtaining current period mass and current period profile point cloud data of each testing period; performing space registration and high-fixed slice processing based on the three-dimensional space coordinate system to determine tooth tip morphology degradation characteristics of each period; performing local fluctuation statistical analysis based on the morphology degradation characteristics to determine a morphology failure inflection point and extract effective service mass loss; and determining a comprehensive service wear rate in combination with the initial mass, single-period penetration action frequency and effective service mass loss. The present application accurately strips invalid wear data after morphology failure of the bucket tooth, and improves the accuracy of the wear rate.

Description

Technical Field

[0001] This invention relates to the field of performance testing and evaluation of wear-resistant materials for engineering machinery, specifically to a method and apparatus for testing the wear rate of wear-resistant bucket teeth. Background Technology

[0002] In the fields of engineering machinery manufacturing and mining, wear-resistant bucket teeth, as the terminal actuators of excavator and loader buckets, directly participate in cutting and crushing rock, soil, and ore, and are core high-frequency wear parts. When developing wear-resistant bucket teeth for different alloy ratios or heat treatment processes, it is urgent to obtain accurate wear rate evaluation indicators through standardized laboratory bench testing, so as to serve as a theoretical basis for smelting formula and process optimization.

[0003] Currently, the industry's conventional methods for testing bucket tooth wear rate are mainly based on traditional abrasive wear testing equipment, such as rubber wheel dry sand abrasion testers or rotary drum abrasion testers. The core testing logic is as follows: the bucket tooth to be tested is placed in a device containing abrasive media for continuous friction testing. A fixed test duration or cycle is preset. The initial mass of the sample before the test and the final mass of the sample after the test are weighed by an electronic balance, and the mass loss is calculated. Then, the average mass loss per unit time or per unit action cycle is calculated and used as the wear rate to evaluate the wear resistance performance of the bucket tooth.

[0004] However, the aforementioned evaluation method based on fixed test duration and overall mass loss suffers from a flaw in evaluating the effective service life wear rate at the macroscopic mechanics and practical engineering application levels. Specifically, under actual excavation conditions, bucket teeth primarily endure high-stress chiseling wear. The tooth tips are prone to rapid degradation due to localized stress concentration, causing the front-end cutting mechanism to transform into a high-resistance squeezing friction mechanism. Because existing testing methods lack dynamic monitoring of the bucket tooth's spatial geometry degradation process, they cannot accurately capture the physical critical point of morphological failure. This leads to the testing equipment continuing to operate after the bucket tooth's morphological failure, generating ineffective frictional wear that deviates from actual service conditions. Existing evaluation systems superimpose and amortize the ineffective wear mass generated at this stage with the normal wear mass within the effective service life, masking the truncation effect of morphological degradation on the actual lifespan. This results in a significant deviation between the output wear rate index and the performance under actual operating conditions.

[0005] Therefore, there is an urgent need for a testing method and system that can dynamically track the trajectory of the spatial morphology degradation of the bucket teeth and accurately extract the critical point of morphological failure, so as to strip away the invalid wear data after morphological failure and restore the true wear rate in engineering service. Summary of the Invention

[0006] To address the problem that existing bucket tooth wear rate testing methods lack morphological monitoring tools and thus cannot identify local morphological failure thresholds, resulting in invalid wear data after failure in the overall test data and distorting the wear rate evaluation index, this invention proposes a wear-resistant bucket tooth wear rate testing method and apparatus.

[0007] On one hand, the present invention provides a method for testing the wear rate of wear-resistant bucket teeth, comprising:

[0008] Step 1: Collect the initial mass and initial contour point cloud data of the bucket tooth to be tested, and construct the three-dimensional spatial coordinate system of the bucket tooth to be tested based on the initial contour point cloud data; Step 2: Control the bucket teeth under test to perform a segmented penetration wear test that includes multiple penetration digging actions, obtain the number of single-cycle penetration actions in each test cycle, and collect the current cycle quality and current cycle contour point cloud data for each test cycle. Step 3: Based on the three-dimensional spatial coordinate system, perform spatial registration and fixed-height slicing processing on the initial contour point cloud data and the current contour point cloud data of each test cycle to obtain the initial tooth tip cross-sectional area and the current tooth tip cross-sectional area of ​​each test cycle, and determine the tooth tip morphology degradation characteristics of each test cycle based on the initial tooth tip cross-sectional area and the current tooth tip cross-sectional area. Step 4: Perform local fluctuation statistical analysis based on the tooth tip morphology degradation characteristics of each test cycle to determine the morphological failure inflection point of the test tooth, and extract the effective service mass loss of the test tooth from the current cycle mass of each test cycle based on the morphological failure inflection point. Step 5: Determine the comprehensive service wear rate of the test tooth by combining the initial mass, the number of single-cycle penetration actions, the morphological failure inflection point, and the effective service mass loss.

[0009] This technical solution, from the perspective of mechanical evolution and data space dimensionality reduction, discretizes the traditional continuous and invisible macroscopic wear process into traceable spatiotemporal physical slices. By introducing a three-dimensional fixed-height slicing mechanism, it accurately maps complex surface geometric deformations into quantitative degradation characteristics directly related to digging resistance. At the same time, it uses local fluctuation statistical analysis to adaptively capture the macroscopic physical failure inflection point where the material cutting mechanism deteriorates. This allows for precise truncation and elimination of invalid wear data generated after the bucket teeth lose their effective penetration capability on the time axis, ensuring that the final comprehensive wear rate index is fully focused within the efficient service life of the bucket teeth, thus improving the accuracy of the wear rate.

[0010] Preferably, in step one, the initial mass and initial contour point cloud data of the bucket tooth to be tested are collected, and a three-dimensional spatial coordinate system of the bucket tooth to be tested is constructed based on the initial contour point cloud data. This includes: collecting the initial mass of the bucket tooth to be tested after surface cleaning and drying, and collecting the initial contour point cloud data of the bucket tooth to be tested using a three-dimensional scanning device; extracting the central axis of the mounting pin hole from the initial contour point cloud data of the bucket tooth to be tested, and constructing a three-dimensional spatial coordinate system of the bucket tooth to be tested using the central axis of the mounting pin hole and the plane where the root mating surface of the bucket tooth to be tested is located.

[0011] This technical solution effectively avoids the coordinate system drift problem caused by wear on the outer working surface of the bucket teeth by selecting the central axis of the mounting pin hole and the tooth root mating surface, which do not directly participate in the abrasive friction contact, as the origin and reference plane of the spatial reference system. It provides an absolutely rigid three-dimensional reference positioning basis for multi-cycle point cloud alignment and spatial dimensionality reduction slicing throughout the entire life cycle.

[0012] Preferably, in step two, obtaining the number of single-cycle penetration actions for each test cycle and collecting the current cycle quality and current cycle contour point cloud data for each test cycle includes: controlling the hydraulic test bench to drive the bucket teeth under test to perform multiple penetration and digging actions in the abrasive box, setting the penetration and digging actions that reach the preset number of single-cycle penetration actions as a test cycle; pausing and cleaning the data collection after each test cycle is completed to obtain the current cycle quality for each test cycle, and using a three-dimensional scanning device to obtain the current cycle contour point cloud data for each test cycle.

[0013] Preferably, in step three, the initial tooth tip cross-sectional area and the current tooth tip cross-sectional area for each test cycle are determined as follows: The unworn mounting pin hole area point cloud is extracted from the initial contour point cloud data, and the unworn mounting pin hole area point cloud is extracted from the current cycle contour point cloud data for each test cycle; the unworn mounting pin hole area point cloud in the current cycle contour point cloud data for each test cycle is overlapped and registered with the unworn mounting pin hole area point cloud in the initial contour point cloud data using spatial translation and rotation matrices to obtain unified coordinate system contour point cloud data for each test cycle; based on the unified coordinate system contour point cloud data for each test cycle and the initial contour point cloud data, a fixed-height slicing process is performed to obtain the initial tooth tip cross-sectional area and the current tooth tip cross-sectional area for each test cycle of the bucket tooth to be tested.

[0014] This technical solution explicitly limits the use of point clouds in the unworn mounting pin hole area to perform spatial translation and rotation matrix registration, eliminating the interference caused by severe nonlinear wear deformation in the tooth tip area on the point cloud registration process, and improving the spatial position mapping accuracy of cross-cycle point cloud mapping to a unified coordinate system.

[0015] Preferably, in step three, the fixed-height slicing process includes: extracting the initial tooth tip extreme point from the initial contour point cloud data, extracting the current tooth tip extreme point from the unified coordinate system contour point cloud data of each test cycle; and generating corresponding parallel cutting planes at fixed physical distances from the initial tooth tip extreme point and from the current tooth tip extreme point, respectively, based on the vertical direction pointing to the tooth tip in the three-dimensional spatial coordinate system.

[0016] Preferably, in step three, the tooth tip morphology degradation features of each test cycle are determined as follows: the area of ​​the intersection polygon between the parallel tangent plane corresponding to the initial tooth tip extreme point and the initial contour point cloud data is extracted to obtain the initial tooth tip cross-sectional area; the area of ​​the intersection polygon between the parallel tangent plane corresponding to the current tooth tip extreme point and the unified coordinate system contour point cloud data of each test cycle is extracted to obtain the current tooth tip cross-sectional area of ​​each test cycle; the area expansion between the current tooth tip cross-sectional area and the initial tooth tip cross-sectional area is determined as the tooth tip morphology degradation feature.

[0017] This technical solution reduces the complex three-dimensional point cloud topology processing to two-dimensional cross-sectional area calculation. By generating parallel tangent planes at a fixed physical distance from the initial tooth tip extreme point, it can intuitively and efficiently capture the physical stress section that is positively correlated with the actual excavation cutting resistance. At the same time, the cross-sectional area expansion is defined as the morphological degradation characteristic, which accurately maps the material failure essence of the bucket teeth evolving from sharp penetration to flat and blunt compression of soil.

[0018] Preferably, in step four, local fluctuation statistical analysis is performed based on the tooth tip morphological degradation characteristics of each test cycle to determine the morphological failure inflection point of the test tooth, including: obtaining the degradation area change rate of each test cycle based on the difference between the tooth tip morphological degradation characteristics of each test cycle and the adjacent test cycles; after excluding a first preset number of test cycles, the subsequent consecutive test cycles are determined as a stable wear stage; the average value and sample standard deviation of the degradation area change rate of each test cycle within the stable wear stage are extracted, and a failure judgment threshold is constructed based on the average value and the sample standard deviation using the three-times standard deviation rule; after the stable wear stage, the first test cycle in which the degradation area change rate of a second preset number of consecutive test cycles is greater than the failure judgment threshold is determined as the morphological failure inflection point.

[0019] This technical solution introduces an adaptive industrial local fluctuation statistical control mechanism. By extracting statistical features of the stable wear stage to construct a dynamic judgment threshold, and in conjunction with the joint verification logic of continuously preset number of out-of-tolerance, it effectively filters out the accidental measurement jumps caused by large hard rocks in the test, and accurately captures the physical failure inflection point when the hardened layer on the surface of the bucket teeth is damaged or the cutting mechanism undergoes macroscopic deterioration.

[0020] Preferably, constructing a failure determination threshold by combining the mean and the sample standard deviation includes: summing the mean and three times the sample standard deviation based on the three-standard-deviation rule in statistics to obtain the failure determination threshold.

[0021] Preferably, in step four, extracting the effective service mass loss of the test tooth from the current cycle mass of each test cycle based on the morphological failure inflection point includes: extracting the critical cycle mass corresponding to the morphological failure inflection point from the current cycle mass of each test cycle; and determining the absolute mass difference between the initial mass of the test tooth and the critical cycle mass as the effective service mass loss of the test tooth.

[0022] This technical solution establishes a quality cutoff evaluation criterion that eliminates false data and requires that only the critical periodic quality that strictly corresponds to the inflection point of morphological failure be extracted. This mechanism completely removes the invalid friction consumption data that the bucket teeth continuously generate in the test bench after losing their effective penetration ability, ensuring that the final calculated consumption occurs entirely within the actual service range where the bucket teeth still have efficient digging capabilities.

[0023] Preferably, in step five, determining the comprehensive service wear rate of the bucket tooth under test by combining the initial mass, the number of single-cycle penetration actions, the morphological failure inflection point, and the effective service mass loss includes: obtaining the total number of effective operating actions of the bucket tooth under test based on the morphological failure inflection point and the number of single-cycle penetration actions in each test cycle; calculating the product of the initial mass of the bucket tooth under test and the total number of effective operating actions; using the ratio of the effective service mass loss of the bucket tooth under test to the product as the reference wear rate of the bucket tooth under test; and using a preset engineering amplification factor to numerically modulate the reference wear rate to obtain the comprehensive service wear rate of the bucket tooth under test.

[0024] This technical solution accurately distributes the effective service mass loss to the single effective operation action and the unit initial mass, eliminating the evaluation error caused by the difference in initial volume or weight of different batches and specifications of bucket teeth, and uses the engineering amplification factor for standardized numerical modulation, so that the output evaluation index has both theoretical rigor and practical feasibility.

[0025] On the other hand, the present invention provides a wear-resistant bucket tooth wear rate testing device, comprising: The parameter acquisition unit is used to acquire the mass parameters and three-dimensional contour point cloud data of the bucket tooth to be tested; A penetration simulation test bench is used to drive the bucket teeth under test to perform a segmented wear test involving multiple penetration actions in an abrasive medium; The calculation and processing unit is configured to: based on the data obtained by the parameter acquisition unit and the penetration simulation test bench, execute the wear-resistant bucket tooth wear rate test method described above, so as to output the comprehensive service wear rate of the bucket tooth to be tested.

[0026] The present invention has the following effects: This invention combines three-dimensional spatial height slicing with adaptive local fluctuation statistical analysis to achieve dynamic tracking of the complex physical morphological degradation trajectory of bucket teeth and accurate identification of failure inflection points. This process removes invalid wear data generated after the bucket teeth fail and are scrapped, thereby improving the accuracy of wear rate evaluation indicators during the effective service life. Attached Figure Description

[0027] Figure 1 This is a schematic flowchart of the wear rate testing method for wear-resistant bucket teeth provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the degradation area change rate curve and morphological failure inflection point identification provided in an embodiment of the present invention; Figure 3 This is a statistical chart comparing the running cycles of the traditional testing method and the testing method of the present invention provided in the embodiments of the present invention; Figure 4 This is a comparison chart of mass loss data between the traditional testing method provided in this embodiment and the testing method of this invention. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0029] like Figure 1 As shown, the present invention provides a method for testing the wear rate of wear-resistant bucket teeth, comprising: Step 1: Collect initial data of the bucket teeth to be tested and construct a three-dimensional spatial coordinate system.

[0030] Since any wear calculation must be based on an accurate unworn reference surface, in order to accurately calculate mass changes and precisely analyze the degradation of macroscopic spatial morphology in subsequent steps, it is necessary to obtain initial data on the absolute physical state of the bucket teeth before testing, and to establish a reference coordinate system that does not undergo relative displacement throughout the entire wear cycle using a fixed structure that does not participate in wear, so as to provide an absolutely rigid reference starting point for subsequent multi-cycle spatial profile alignment and mass calculation.

[0031] Specifically, the initial mass of the bucket tooth to be tested after surface cleaning and drying is collected, and the initial contour point cloud data of the bucket tooth to be tested is collected using a three-dimensional scanning device. The central axis of the mounting pin hole in the initial contour point cloud data of the bucket tooth to be tested is extracted, and the three-dimensional spatial coordinate system of the bucket tooth to be tested is constructed using the central axis of the mounting pin hole and the plane where the tooth root mating surface of the bucket tooth to be tested is located.

[0032] In this construction process, in order to completely eliminate the residual rotational degree of freedom in the six degrees of freedom of space, the anti-rotation latch or positioning boss feature points inside the pin hole are further extracted to establish the direction vector, thereby completing the unique constraint of the absolute coordinates.

[0033] When acquiring parameters, the surface of the bucket teeth to be tested is first ultrasonically cleaned to remove rust-preventive oil and cutting impurities, and then dried with hot air to avoid surface impurities causing errors in the initial mass. Next, the initial mass of the bucket teeth to be tested is measured using a high-precision industrial electronic balance and recorded as follows: Subsequently, an industrial binocular structured light 3D scanner was used to perform an all-around scan of the bucket tooth under test to obtain initial contour point cloud data.

[0034] Since the mounting pin hole at the rear end of the bucket tooth under test and the inner cavity of the tooth root both mate with the excavator's tooth seat during actual service and do not directly contact the abrasive, no wear will occur. Based on this, using the plane where the tooth root mating surface is located as the reference plane (XY plane), and the direction perpendicular to this reference plane and pointing towards the tooth tip as the Z-axis, the central axis of the mounting pin hole is extracted, and the projection direction of the central axis on the reference plane is defined as the X-axis, thereby constructing the three-dimensional spatial coordinate system of the bucket tooth under test.

[0035] This step achieves precise initialization of physical state and geometry, obtains initial mass and initial contour point cloud data with constant coordinate system information, and eliminates the potential risk of inaccurate alignment of subsequent multi-stage scanning point clouds due to arbitrary coordinate system settings.

[0036] In a specific example, before a batch of high-manganese steel bucket teeth to be tested were placed in the test, they were ultrasonically cleaned and dried with hot air. The initial mass of the bucket teeth was measured to be 8.52 kg using an industrial electronic balance. The initial contour point cloud data of the three-dimensional coordinate points of the bucket teeth were obtained using a three-dimensional scanning device, and the origin (0,0,0) was automatically positioned at the center of the unworn mounting pin hole at the tail to establish a three-dimensional spatial coordinate system.

[0037] Step 2: Perform segmented penetration wear tests and analyze each test cycle.

[0038] After establishing static physical and geometric benchmarks, considering that traditional drum wear testing methods often involve running the bucket teeth in the drum for a fixed time, this continuous friction cannot truly reflect the physical force state of the bucket teeth chiseling and cutting into the material in actual mines, and the continuous wear process masks the dynamic morphological degradation trajectory.

[0039] Therefore, this step aims to build a dynamic evolution observation platform that conforms to real working conditions. It simulates real penetration action through hydraulic drive and discretizes the continuous wear process into multiple test cycles with clear boundaries. Through periodic pauses and data acquisition, discrete snapshots on the time series are generated. The purpose is to provide continuous multi-dimensional data support for subsequent tracking of the physical evolution of bucket teeth from sharp to blunt.

[0040] Specifically, the hydraulic test bench is controlled to drive the bucket teeth under test to perform multiple penetration and digging actions in the abrasive box. The penetration and digging actions that reach the preset number of penetration actions per cycle are set as a test cycle. After each test cycle is completed, the data is paused for cleaning and collection to obtain the current cycle quality of each test cycle. The current cycle contour point cloud data of each test cycle is obtained using a 3D scanning device.

[0041] First, a test scenario is set up. The bucket tooth to be tested is fixed to the robotic arm of the hydraulic test bench by a pin. An abrasive box containing compacted graded quartz sand and gravel is set under the hydraulic test bench. The robotic arm is controlled to cut into the abrasive box at a 30-degree angle, which is the normal operating angle of the excavator, and the rated thrust is applied to press the bucket tooth to be tested into the abrasive box to the set depth. Then, it is flipped and pulled out to complete one penetrating excavation action.

[0042] To prevent the graded quartz sand and gravel in the abrasive box from undergoing compaction and hardening effects with increasing penetration times, which could lead to a drift in the boundary conditions of cutting resistance in the later stages of the test, the fluidization and loosening device at the bottom of the abrasive box is automatically activated during the intervals between multiple penetration actions to maintain the global dynamic constant density of the abrasive medium.

[0043] To quantify the testing progress, a pre-set number of penetration actions per cycle is used as the workload for one testing cycle. This number of penetration actions per cycle is usually set to 500. This is because too few actions will lead to excessive downtime and affect efficiency, while too many actions will result in a large morphological degradation span between two cycles, causing the loss of critical failure inflection point information.

[0044] When the test reaches 500 times, the hydraulic test bench is paused, the bucket teeth to be tested are removed, and the surface sand and gravel are cleaned with a high-pressure air gun. The current mass is weighed again using a balance to obtain the current mass of each test cycle. At the same time, the bucket teeth to be tested are fixed on a special fixture, and their current shape is obtained using a 3D scanning device to obtain the current contour point cloud data of each test cycle.

[0045] This step successfully transforms the wear process into visible time-series data, yielding quality and three-dimensional profile snapshots for each test cycle.

[0046] Following the example from step one, the bucket tooth to be tested, with an initial mass of 8.52 kg, is installed on a hydraulic test bench. The number of penetration actions per cycle is set to 500. After the hydraulic test bench completes the 4th test cycle, that is, after a cumulative total of 2000 penetration and digging actions, the equipment is paused, the bucket tooth to be tested is cleaned, and then weighed. The current cycle mass of the 4th test cycle is 8.315 kg. At the same time, the current cycle contour point cloud data of the 4th test cycle is generated by scanning with a 3D scanning device.

[0047] Step 3: Extract the tooth tip morphology degradation features for each test cycle.

[0048] After acquiring independent 3D point cloud snapshots for each test cycle, these point cloud data are spatially isolated. Directly observing or calculating the overall mass difference cannot quantify the most critical cutting morphology changes at the front end of the bucket teeth. Since bucket tooth failure is essentially caused by the flattening of the tooth tips, leading to a shift from cutting to compression, a single overall mass reduction cannot quantify this local morphological degradation. This step utilizes the coordinate system established in step one to map the independent point cloud data from each test cycle to the same space. Through spatial height slicing, the complex 3D deformation is reduced to a physical expansion process of a 2D cross-sectional area, accurately extracting the macroscopic physical quantities directly related to the actual penetration resistance.

[0049] Therefore, this step aims to establish an absolute spatial mapping relationship. By extracting the unworn area as a rigid reference, the point cloud is overlaid and registered, and sliced ​​at a fixed physical height. This step is essentially a physical expansion process of reducing the complex three-dimensional deformation to a two-dimensional cross-sectional area. The purpose is to accurately peel out the local degradation features that are positively correlated with the actual excavation cutting resistance, so that the morphological failure has a calculable mathematical basis.

[0050] Specifically, based on a three-dimensional spatial coordinate system, spatial registration and height-fixed slicing are performed on the initial contour point cloud data of the test tooth and the current contour point cloud data of each test cycle to obtain the initial tooth tip cross-sectional area and the current tooth tip cross-sectional area of ​​each test cycle. Based on the initial tooth tip cross-sectional area and the current tooth tip cross-sectional area, the tooth tip morphological degradation characteristics of each test cycle are determined, including: The point cloud of the unworn mounting pin hole region is extracted from the initial contour point cloud data, and the point cloud of the unworn mounting pin hole region in the current cycle contour point cloud data of each test cycle is also extracted. Using spatial translation and rotation matrices, the point cloud of the unworn mounting pin hole region in the current cycle contour point cloud data of each test cycle is aligned with the point cloud of the unworn mounting pin hole region in the initial contour point cloud data. In calculating the registration matrix, an iterative nearest-point algorithm is used to minimize and converge the error, and an RMSE (root mean square error) threshold is set to ensure the rigidity of the alignment, resulting in contour point cloud data in a unified coordinate system for each test cycle.

[0051] First, the mounting pin hole area point cloud, which is at the rear and does not participate in wear, is extracted from the point cloud of each test cycle as an alignment reference. A rigid transformation algorithm (spatial translation and rotation matrix) is used to forcibly align the mounting pin hole area point cloud of each test cycle to the mounting pin hole area point cloud of the initial contour, so that all point clouds are mapped to the unique three-dimensional spatial coordinate system established in step one, and the unified coordinate system contour point cloud data of each test cycle is obtained.

[0052] Then, the initial tooth tip extreme point is extracted from the initial contour point cloud data, and the corresponding current tooth tip extreme point is extracted from the unified coordinate system contour point cloud data of each test cycle. Based on the three-dimensional spatial coordinate system, along the Z-axis direction pointing to the tooth tip, a tangent plane parallel to the tooth root reference plane (XY plane) is generated at a distance of 15 mm from the initial tooth tip extreme point and at a distance of 15 mm from the current tooth tip extreme point of each test cycle. 15 mm is an empirical value set in combination with the average particle size and cutting depth of the local ore during actual mining, and is used to characterize the key section height that the bucket tooth mainly bears the penetration resistance.

[0053] Next, the area of ​​the intersection polygon between the parallel tangent plane and the initial contour point cloud data is extracted to obtain the initial tooth tip cross-sectional area. The area of ​​the intersection polygon between the parallel tangent plane and the unified coordinate system contour point cloud data of each test cycle is extracted to obtain the current tooth tip cross-sectional area of ​​each test cycle.

[0054] Finally, the tooth cusp morphology degradation characteristics are calculated, satisfying the following relationship:

[0055] In this relation, This is the sequence number of the test cycle. For the first The tooth tip morphology degradation characteristics over each test cycle reflect the physical expansion of the front-end cross-sectional area. For the first The current tooth tip cross-sectional area of ​​a test cycle reflects the cross-sectional size of the current test cycle. The larger the value, the wider the cross-section. The initial tooth tip cross-sectional area is a benchmark value that reflects the sharpness of the bucket tooth under test when it is not worn.

[0056] This formula assesses the loss of sharpness increment due to tooth tip wear. It merges the two area terms through subtraction, taking into account that in actual excavation and cutting processes, the real factor affecting operational efficiency is the loss of sharpness increment due to tooth tip wear. After several cycles of penetrating excavation, the current tooth tip cross-sectional area will be significantly larger than the initial tooth tip cross-sectional area, leading to a gradual increase in the final morphological degradation characteristics. This corresponds to the phenomenon of continuously increasing excavator bucket cutting resistance in physical scenarios.

[0057] In this way, by calculating the difference in area, the minute three-dimensional deformation is transformed into a two-dimensional area increment that reflects the loss of penetrability, thus achieving the effect of accurately quantifying local morphological degradation.

[0058] Following the example from step two, after aligning the point cloud for the fourth cycle, establish parallel tangent planes at points 15 mm vertically descending from the initial tooth tip extreme point and at points 15 mm vertically descending from the current tooth tip extreme point in the fourth cycle, respectively, and calculate the initial tooth tip cross-sectional area. The current tooth tip cross-sectional area is 120 square millimeters in the fourth test cycle. The area is 210 square millimeters, then the tooth tip morphology degradation characteristics of the 4th cycle are... Square millimeters, which means that after 2000 diggings, the contact surface of the tested bucket tooth expanded by 90 square millimeters.

[0059] Step 4: Extract the morphological failure inflection point and the effective service quality loss.

[0060] The surface of bucket teeth usually has a hardened layer. When the hardened layer is worn through or the shape causes severe soil accumulation, the expansion rate of the wear area will undergo a step-like change. At this time, the bucket teeth have essentially lost their efficient working ability, and subsequent wear and tear tests are meaningless.

[0061] Therefore, this step aims to establish an adaptive data truncation mechanism. By analyzing the rate of change of degradation area in adjacent cycles and constructing a judgment threshold based on statistical benchmarks in the stable wear stage, this mechanism captures the moment of sudden change caused by material structure deterioration or cutting mechanism transformation, accurately locates the inflection point of physical failure, thereby cutting off subsequent ineffective and blind frictional consumption that has no engineering significance, and extracting the quality loss that truly reflects the effective service life.

[0062] Specifically, based on the tooth tip morphology degradation characteristics of each test cycle, local fluctuation statistical analysis is performed to determine the morphological failure inflection point of the test tooth, and based on the morphological failure inflection point, the effective service quality loss of the test tooth is extracted from the current cycle quality of each test cycle.

[0063] First, based on the difference in tooth tip morphological degradation characteristics between adjacent test cycles, the degradation area change rate is obtained. This indicator represents the rate of wear development, for example: , For the first The rate of change of degraded area over each test period For the first Tooth tip morphology degradation characteristics over one test cycle. For the first Tooth tip morphology degradation characteristics over a test cycle.

[0064] When new bucket teeth are first tested, they usually experience a very short initial break-in period. During this period, the microscopic protrusions on the surface are quickly smoothed out or the decarburized layer peels off, and the wear rate is unstable. Therefore, the initial two very short test cycles (the first preset number) are used as the break-in period for elimination. Subsequently, the hardened layer on the surface of the bucket teeth plays a major role in anti-wear, and the wear enters a stable period. The six consecutive test cycles after the break-in period (the second preset number), namely the third to the eighth test cycles, are determined as the stable wear stage.

[0065] Then, the average value of the rate of change of degradation area during the steady wear stage is calculated. and sample standard deviation To ensure the mathematical validity of the algorithm under extreme distributions, a lower bound for variance bias prevention was set. ,like Then force Assign a lower limit value To prevent computational anomalies, a failure threshold is constructed based on the statistical rule of three standard deviations, satisfying the following relationship:

[0066] In this relation, The failure threshold reflects the statistical upper limit of the area expansion rate of bucket teeth under normal and stable wear conditions. The average value of the rate of change of degradation area during the stable wear stage reflects the average degradation rate when the hardened layer provides stable wear resistance. The larger the value, the worse the wear resistance of the material base. The sample standard deviation of the degradation area change rate during the stable wear stage reflects the degree of fluctuation in the degradation rate; the larger the value, the more uneven the wear.

[0067] This formula combines the average rate term and the three-times upper limit of fluctuation term through addition, and its design logic originates from the three-times standard deviation rule in industrial quality control. In normal wear scenarios, due to the random distribution of test sand particles, the rate of change will fluctuate around the mean. The reference position has been determined. It provides a tolerant fluctuation range, and the threshold formed by adding the two means that if the rate of change in a certain test period exceeds... The probability of this fluctuation being merely a random occurrence caused by encountering a large, hard rock is extremely small. However, the most likely cause is a fundamental change in the physical structure, such as the exhaustion of the high-hardness surface layer or a severely compressed and bridging effect due to an excessively blunt tip. This allows for adaptive alarm threshold setting, accurately filtering out random measurement noise, and identifying genuine physical failure mutations.

[0068] Finally, after the stable wear stage, each test cycle was monitored sequentially. To prevent false judgments, a verification mechanism was set up for a preset number of consecutive cycles. When the rate of change of degradation area for three consecutive test cycles was strictly greater than the failure judgment threshold, the failure was determined. Only when this point was reached was irreversible morphological failure determined, indicating that the high-hardness layer had completely failed. The first test cycle of these three consecutive test cycles was then identified as the inflection point of morphological failure. After finding the inflection point, the total number of test cycles corresponding to the inflection point of this failure mode is recorded as follows: The current period mass corresponding to this period is retrieved as the critical period mass. , initial mass Subtract the critical period mass The absolute difference was calculated to obtain the effective service mass loss after removing the ineffective frictional wear in the later stages. .

[0069] Following the example from step three, after calculating the data from the initial stable wear stage, the average value of the degradation area change rate is obtained. For 15 square millimeters per test cycle, the sample standard deviation is... Failure determination threshold: 2 square millimeters per test cycle In each test cycle, the calculated degradation area change rate was 23, 25, and 26 square millimeters per test cycle for cycles 25, 26, and 27, respectively. Since the rate was greater than 21 for three consecutive cycles, the 25th test cycle was automatically determined as the morphological failure inflection point. The current cycle mass for the 25th test cycle was then retrieved, and the critical cycle mass was determined to be 7.92 kg. The absolute difference between the initial mass and the critical cycle mass was taken as the effective service mass loss. kilogram.

[0070] Step 5: Determine the overall service wear rate.

[0071] After extracting the mass loss that truly reflects the effective operating range, in order to establish a fair lateral comparison system between bucket teeth of different batches and specifications, it is necessary to eliminate the error caused by the initial volume or weight difference.

[0072] This step removes the effective mass loss after ineffective friction and accurately distributes it to a single effective working action and the unit initial mass, completing multi-parameter normalization calculations to ensure that the indicators objectively reflect its actual comprehensive wear resistance properties in the mine.

[0073] Specifically, the comprehensive service wear rate of the bucket tooth under test is determined by combining the initial mass, the number of single-cycle penetration actions, the morphological failure inflection point, and the effective service mass loss. This includes: obtaining the total number of effective operating actions of the bucket tooth under test based on the morphological failure inflection point and the number of single-cycle penetration actions in each test cycle; calculating the product of the initial mass of the bucket tooth under test and the total number of effective operating actions; using the ratio of the effective service mass loss of the bucket tooth under test to this product as the reference wear rate of the bucket tooth under test; and using a preset engineering amplification factor to numerically modulate the reference wear rate to obtain the comprehensive service wear rate of the bucket tooth under test.

[0074] First, multiply the total number of cycles corresponding to the morphological failure inflection point by the number of penetration actions per cycle to obtain the total number of effective operating actions that the bucket teeth could actually perform before failure. Multiply this total number by the initial mass of the bucket teeth to form a denominator term.

[0075] Next, the overall service wear rate is calculated, satisfying the following relationship:

[0076] In this relation, The comprehensive service wear rate of the bucket teeth under test is used to characterize the mass consumed per unit initial mass in each effective digging action. The smaller the value, the better the comprehensive wear resistance of the material. The effective service mass loss of the bucket tooth under test reflects the absolute wear of the bucket tooth during its penetrating ability. The smaller the value, the more wear-resistant it is. Let be the initial mass of the bucket tooth to be tested. This is the inflection point of morphological failure. For the number of times per cycle, This represents the total number of effective operating actions, reflecting the lifespan of the bucket teeth before they reach their functional failure state. The larger the value, the longer the bucket teeth remain sharp. The preset engineering magnification factor is usually taken as... It is used to convert the extremely small basic amount of wear from a single effective action into an intuitive value that is easy to record in engineering and compare laterally, that is, to convert the unit dimension of the calculation result from kilogram to milligram.

[0077] In this step, to absolutely prevent unexpected division-to-zero crashes during automated calculation, boundary condition constraint logic is added to forcibly verify that the denominator variable must satisfy... The specific constraint mechanism is as follows: before performing the division operation, determine the value of the morphological failure inflection point; if... This indicates that the tested bucket teeth failed to reach the stable wear stage before experiencing early brittle fracture and other failures. To ensure the integrity of the testing and evaluation system, an extreme value penalty mechanism will be triggered, forcibly setting... Furthermore, the mass difference during the shutdown due to failure is used as the effective service mass loss and substituted into the subsequent comprehensive service wear rate calculation, ensuring that the testing device can still output effectively when faced with extremely abnormal samples.

[0078] This formula integrates the effective wear amount with the test benchmark through division, distributing the absolute wear amount evenly across each working action and each kilogram of initial body weight. This represents the total service workload. When the material is of high quality, the effective service mass loss is small, and it can be maintained for a very long time before a morphological change occurs, resulting in a large total number of effective operating actions. This increases the denominator and decreases the numerator, ultimately leading to a significantly lower overall service wear rate, signifying the high-quality wear-resistant characteristics of the bucket teeth. Conversely, if the material surface hardness is insufficient, rapid wear occurs, resulting in a small total number of effective operating actions and a large overall service wear rate. Since the wear amount of a single action is extremely small, an engineering amplification factor is used for numerical modulation and multiplication amplification, changing the unit of the final result from kilograms to micrograms, facilitating direct recording and comparison by engineers.

[0079] In this way, by dividing the physical wear data by the frequency of action and weight benchmarks, the interference of invalid data continuously generated in the test bench after the bucket teeth are scrapped is eliminated, and an accurate evaluation of the wear resistance of real engineering service is achieved.

[0080] Following the example from step four, the initial mass of the bucket tooth to be tested is known. kilograms, effective service mass loss The weight is 0.6 kg, the morphological failure inflection point is the 25th cycle, the number of penetration actions per cycle is 500, therefore the total number of effective operation actions is... Second, engineering magnification factor Take 1,000,000 and substitute it into the calculation: Comprehensive service wear rate The physical meaning of this comprehensive service wear rate is: the mass loss generated per kilogram of initial bucket teeth in a single effective digging action, and its calculation unit is milligrams. This comprehensive service wear rate eliminates all invalid blind friction losses after the 25th test cycle, providing production personnel with a true material wear benchmark.

[0081] To visually verify the technical effectiveness of this invention in extracting morphological failure inflection points and eliminating invalid wear data, a comparative verification test was conducted using a high-manganese steel bucket tooth with an initial mass of 8.52 kg as an example, in an abrasive box filled with graded quartz sand and crushed stone. The single-cycle penetration action was set to 500 times, and the running data was continuously recorded and compared. The results are as follows: Figures 2 to 4The test process and results are shown in the comparison chart.

[0082] Combination Figure 2 Analysis shows that the curve objectively reflects the local physical degradation trajectory of the bucket teeth during the testing cycle. In the initial stage of testing, the bucket teeth are in a break-in period with microscopic protrusions on the surface, and the fluctuations are irregular. After entering the 3rd to 8th cycles, the surface hardened layer begins to play a stable anti-wear role, and the rate of change of degradation area enters a stable fluctuation range. Statistical characteristics of this range are extracted, and the failure judgment threshold T is calculated to be 20.53. When the test progresses to the 25th cycle, the rate of change of degradation area first exceeds this threshold and then oscillates violently at a high level in subsequent cycles. From an engineering mechanics perspective, this physical phenomenon indicates that the shape of the front tooth tip of the bucket teeth becomes severely blunt, causing the cutting mechanism to change into a squeezing mechanism with extremely high resistance. The 25th cycle is precisely identified as the inflection point of morphological failure.

[0083] Combination Figure 3 Analysis shows that the statistical chart reflects the macroscopic difference in equipment operating costs between the two testing methods. The traditional fixed-duration testing method executes a preset 35 test cycles, while the present invention immediately stops the effectiveness evaluation after identifying the failure inflection point in the 25th cycle. The extra 10 test cycles occur during the operational phase when the bucket teeth lose their actual penetration capability. The adaptive cutoff mechanism of the present invention avoids the test data generated by meaningless test bench operation.

[0084] Combination Figure 4 Analysis shows that the comparison chart reveals the data quality that leads to the distortion of traditional wear assessment. Under the traditional method, the total mass loss included in the calculation is as high as 0.952 kg, which includes 0.385 kg of invalid wear caused by continued friction after the failure of the bucket tooth shape. This calculation method conflates the extrusion wear after passivation with the cutting wear during the sharp period, diluting the true wear rate in the early stage. In contrast, this invention uses physical truncation based on the failure inflection point of the 25th cycle, extracting only 0.567 kg of effective service mass loss. Through the stripping process, it ensures that the comprehensive service wear rate calculated subsequently focuses on the actual service cycle in which the bucket tooth has efficient operation capability, thus ensuring the purity of the evaluation index.

[0085] This invention also provides a wear-resistant bucket tooth wear rate testing device, which is an automated bench integrating a heavy-duty hydraulic servo system and a digital precision measurement system. The core consists of a servo hydraulic robotic arm with multi-degree-of-freedom motion trajectory. Engineers fix the bucket tooth to be tested to the end of the robotic arm with a pin. A large abrasive box is set below it. The abrasive box is filled with graded quartz sand and crushed stone mixed in a specific ratio. In order to simulate the hard strata of real mines, the bottom of the box is equipped with a fluidizing and loosening device to ensure that the compaction and physical properties of the abrasive remain dynamically consistent before each penetration action, avoiding experimental errors caused by compaction hardening.

[0086] On the outside of the platform, the device integrates a high-precision industrial structured light 3D scanner and a thousand-level electronic balance. After the robotic arm completes the preset 500 cycles of pressing, flipping and pulling out, the device will automatically guide the robotic arm to the cleaning position, peel off the surface attachments with a high-pressure air gun, and then the scanner and balance will simultaneously collect the residual mass of the bucket teeth and the surface point cloud data.

[0087] The core control unit of the device is the computing processing unit, which is responsible for transmitting the collected periodic point cloud data to the algorithm module in real time and performing spatial alignment based on the pin hole reference. Engineers can intuitively see the area expansion trajectory of the bucket tooth tip due to wear through the monitoring terminal. When the system detects a step change in the cross-sectional area expansion rate, that is, when the failure threshold is triggered, the device will automatically lock that moment as the inflection point of morphological failure and output the comprehensive service wear rate.

[0088] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for testing the wear rate of wear-resistant bucket teeth, characterized in that, include: Step 1: Collect the initial mass and initial contour point cloud data of the bucket tooth to be tested, and construct the three-dimensional spatial coordinate system of the bucket tooth to be tested based on the initial contour point cloud data; Step 2: Control the bucket teeth under test to perform a segmented penetration wear test that includes multiple penetration digging actions, obtain the number of single-cycle penetration actions in each test cycle, and collect the current cycle quality and current cycle contour point cloud data for each test cycle. Step 3: Based on the three-dimensional spatial coordinate system, perform spatial registration and fixed-height slicing processing on the initial contour point cloud data and the current contour point cloud data of each test cycle to obtain the initial tooth tip cross-sectional area and the current tooth tip cross-sectional area of ​​each test cycle, and determine the tooth tip morphology degradation characteristics of each test cycle based on the initial tooth tip cross-sectional area and the current tooth tip cross-sectional area. Step 4: Perform local fluctuation statistical analysis based on the tooth tip morphology degradation characteristics of each test cycle to determine the morphological failure inflection point of the test tooth, and extract the effective service mass loss of the test tooth from the current cycle mass of each test cycle based on the morphological failure inflection point. Step 5: Determine the comprehensive service wear rate of the test tooth by combining the initial mass, the number of single-cycle penetration actions, the morphological failure inflection point, and the effective service mass loss.

2. The method for testing the wear rate of wear-resistant bucket teeth according to claim 1, characterized in that, In step one, the initial mass and initial contour point cloud data of the bucket tooth to be tested are collected, and a three-dimensional spatial coordinate system of the bucket tooth to be tested is constructed based on the initial contour point cloud data, including: The initial mass of the bucket tooth to be tested after surface cleaning and drying is collected, and the initial contour point cloud data of the bucket tooth to be tested is collected using a three-dimensional scanning device; the central axis of the mounting pin hole in the initial contour point cloud data of the bucket tooth to be tested is extracted, and the three-dimensional spatial coordinate system of the bucket tooth to be tested is constructed using the central axis of the mounting pin hole and the plane where the tooth root mating surface of the bucket tooth to be tested is located.

3. The method for testing the wear rate of wear-resistant bucket teeth according to claim 1, characterized in that, In step two, the number of penetration actions per test cycle is obtained, and the current cycle quality and current cycle contour point cloud data are collected for each test cycle, including: The hydraulic test bench is controlled to drive the bucket teeth under test to perform multiple penetration and digging actions in the abrasive box. The penetration and digging action that reaches the preset number of single-cycle penetration actions is set as a test cycle. After each test cycle is completed, a pause and cleanup process is performed to obtain the current cycle quality of each test cycle, and the current cycle contour point cloud data of each test cycle is obtained using a 3D scanning device.

4. The method for testing the wear rate of wear-resistant bucket teeth according to claim 1, characterized in that, In step three, the initial tooth tip cross-sectional area and the current tooth tip cross-sectional area for each test cycle are determined as follows: Extract the unworn mounting pin hole area point cloud from the initial contour point cloud data, and the unworn mounting pin hole area point cloud from the current cycle contour point cloud data of each test cycle. Using spatial translation and rotation matrices, the unworn mounting pin hole area point cloud in the current period contour point cloud data of each test cycle is superimposed and registered with the unworn mounting pin hole area point cloud in the initial contour point cloud data to obtain the unified coordinate system contour point cloud data for each test cycle. Based on the unified coordinate system contour point cloud data of each test cycle and the initial contour point cloud data, a fixed-height slicing process is performed to obtain the initial tooth tip cross-sectional area of ​​the test tooth and the current tooth tip cross-sectional area of ​​each test cycle.

5. The method for testing the wear rate of wear-resistant bucket teeth according to claim 4, characterized in that, Step three, the fixed-height slicing process includes: The initial tooth tip extreme point is extracted from the initial contour point cloud data, and the current tooth tip extreme point of each test cycle is extracted from the unified coordinate system contour point cloud data of each test cycle. Based on the vertical direction pointing to the tooth tip in the three-dimensional spatial coordinate system, corresponding parallel tangent planes are generated at fixed physical distances from the initial tooth tip extreme point and from the current tooth tip extreme point, respectively.

6. The method for testing the wear rate of wear-resistant bucket teeth according to claim 5, characterized in that, In step three, the tooth tip morphology degradation characteristics for each test cycle are determined as follows: Extract the area of ​​the polygon intersecting the parallel tangent plane and the initial contour point cloud data corresponding to the initial tooth tip extreme point to obtain the initial tooth tip cross-sectional area; Extract the area of ​​the intersection polygon between the parallel tangent plane corresponding to the current tooth tip extreme point and the unified coordinate system contour point cloud data of each test cycle to obtain the current tooth tip cross-sectional area of ​​each test cycle. The area expansion between the current tooth tip cross-sectional area and the initial tooth tip cross-sectional area is determined as the tooth tip morphological degradation feature.

7. The method for testing the wear rate of wear-resistant bucket teeth according to claim 1, characterized in that, In step four, local fluctuation statistical analysis is performed based on the tooth tip morphological degradation characteristics of each test cycle to determine the morphological failure inflection point of the tested bucket tooth, including: Based on the difference in the tooth tip morphology degradation characteristics between adjacent test cycles, the degradation area change rate of each test cycle is obtained; after excluding the first preset number of test cycles, the subsequent consecutive test cycles are determined as the stable wear stage. The average value and sample standard deviation of the degradation area change rate of each test cycle within the stable wear stage are extracted. A failure judgment threshold is constructed based on the average value and the sample standard deviation using the three-times standard deviation rule. After the stable wear stage, the first test cycle in which the degradation area change rate of a second consecutive preset number of test cycles is greater than the failure judgment threshold is determined as the morphological failure inflection point.

8. The method for testing the wear rate of wear-resistant bucket teeth according to claim 1, characterized in that, In step four, the effective service mass loss of the test tooth is extracted from the current cycle mass of each test cycle based on the morphological failure inflection point, including: Extract the critical cycle mass corresponding to the inflection point of the morphological failure from the current cycle mass of each test cycle; The absolute mass difference between the initial mass of the bucket tooth under test and the critical periodic mass is determined as the effective service mass loss of the bucket tooth under test.

9. The method for testing the wear rate of wear-resistant bucket teeth according to claim 1, characterized in that, Step five involves determining the overall service wear rate of the tested bucket tooth by combining the initial mass, the number of single-cycle penetration actions, the morphological failure inflection point, and the effective service mass loss, including: Based on the morphological failure inflection point and the number of single-cycle penetration actions in each test cycle, the total number of effective operating actions of the test tooth is obtained, and the product of the initial mass of the test tooth and the total number of effective operating actions is calculated. The ratio of the effective service mass loss of the bucket tooth under test to the product is used as the reference wear rate of the bucket tooth under test. The reference wear rate is numerically modulated using a preset engineering amplification factor to obtain the comprehensive service wear rate of the bucket tooth under test.

10. A device for testing the wear rate of wear-resistant bucket teeth, characterized in that, include: The parameter acquisition unit is used to acquire the mass parameters and three-dimensional contour point cloud data of the bucket tooth to be tested; A penetration simulation test bench is used to drive the bucket teeth under test to perform a segmented wear test involving multiple penetration actions in an abrasive medium; The calculation and processing unit is configured to: based on the data acquired by the parameter acquisition unit and the penetration simulation test bench, execute the wear-resistant bucket tooth wear rate test method as described in any one of claims 1-9, so as to output the comprehensive service wear rate of the bucket tooth to be tested.

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