Fan blade dynamic balance correction method and correction device thereof

Abstract

The application discloses a fan blade dynamic balance correction method and a correction device thereof, and belongs to the field of fan blade processing and dynamic balance correction. The method comprises the following steps: performing multiple initial dynamic balance detections on a fan blade to be corrected, and converting the detection results to the same fan blade circumferential reference; before the first time of weight removal, determining a clockwise boundary imbalance vector and an anticlockwise boundary imbalance vector according to the multiple dynamic balance detection results, and comparing the reserved correction amount and the remaining allowed correction amount on both sides of each candidate first weight removal scheme, so that the selected first weight removal position is reserved with a processing allowance matched with the subsequent correction, and the corresponding reserved correction area can be selected for further weight removal according to the offset direction of the residual imbalance phase after retesting, thereby solving the problem that the existing correction method is prone to insufficient weight removal space and cannot continue the correction due to the first weight removal position occupying the key processing area.

Description

Technical Field

[0001] This invention relates to the field of fan blade processing and dynamic balancing correction technology, specifically to a fan blade dynamic balancing correction method and correction equipment. Background Technology

[0002] During the manufacturing and assembly process, fan blades are prone to mass eccentricity due to uneven material distribution, hub machining errors, and blade size deviations. Usually, it is necessary to form a weight-reducing pit within the allowable weight-reducing area based on the unbalance amount and unbalance phase obtained from dynamic balance testing. For fan blades with large initial unbalance, it is often necessary to undergo initial weight reduction, retesting, and subsequent weight reduction to achieve the dynamic balance requirements.

[0003] Multiple tests of the same blade may result in phase fluctuations. When the blade is transferred from the test position to the de-weighting position, there may also be angle transmission errors and circumferential positioning errors. Therefore, the residual unbalance phase after the first de-weighting may be biased to either side of the first de-weighting pit, and the direction of subsequent de-weighting is difficult to determine accurately before the first processing.

[0004] After the first de-weighting pit is formed, its opening range and the required spacing between adjacent de-weighting pits will occupy part of the allowable de-weighting area. If the first de-weighting location is close to the boundary of the allowable de-weighting area or there is already a de-weighting pit, although it can reduce the current imbalance, when de-weighting needs to continue on this side after retesting, it may be impossible to complete the correction due to insufficient remaining processing range, insufficient pit spacing, or limited maximum pit depth.

[0005] Existing correction methods typically focus on the current correction effect after the first weight removal, lacking an evaluation of the remaining processing range on both sides of different first weight removal positions and the subsequent correction capability. This can easily lead to the problem that the first weight removal can reduce the imbalance, but after retesting, there are no available weight removal positions on the corresponding side, making it impossible to continue correction. Summary of the Invention

[0006] To address the problems mentioned in the background section, the present invention provides the following technical solution: A method for correcting the dynamic balance of a fan blade includes performing multiple initial dynamic balance tests on the fan blade to be corrected, converting the unbalance phases obtained from each test to the same circumferential reference of the fan blade, and obtaining the initial center unbalance vector, the clockwise boundary unbalance vector, and the counterclockwise boundary unbalance vector. Multiple candidate first-time de-weighting schemes are set within the allowable de-weighting range of the fan blade to be corrected. Each candidate first-time de-weighting scheme includes a candidate first-time de-weighting position and a candidate first-time de-weighting amount. Based on the initial correction vector corresponding to each candidate initial deduplication scheme, the expected residual unbalance vectors after initial correction of the clockwise boundary unbalance vector and the counterclockwise boundary unbalance vector are obtained respectively; according to the pre-calibrated correspondence between the unbalance phase and the deduplication azimuth, the subsequent deduplication reference azimuth on the clockwise side and the subsequent deduplication reference azimuth on the counterclockwise side are determined according to the phases of the two expected residual unbalance vectors respectively, and the portion of the corresponding expected residual unbalance exceeding the allowable residual unbalance is determined as the reserved correction amount on the clockwise side and the reserved correction amount on the counterclockwise side respectively; Based on the circumferential range occupied by the candidate first deduplication pit, the remaining allowable correction amount on the clockwise side of the candidate first deduplication pit in the subsequent deduplication reference position on the clockwise side, and the remaining allowable correction amount on the counterclockwise side in the subsequent deduplication reference position on the counterclockwise side are obtained respectively. The candidate first deduplication scheme in which the remaining allowable correction amount on both sides is not less than the corresponding side reserved correction amount is retained. Calculate the difference between the remaining allowable correction amount and the corresponding reserved correction amount on both sides of each retained candidate first deduplication scheme. Compare the two differences of the same candidate first deduplication scheme and select the candidate first deduplication scheme with the largest smaller difference as the target first deduplication scheme. The first deduplication is completed according to the target first deduplication scheme. The remaining processable range on the clockwise and counterclockwise sides of the first deduplication pit is respectively used as the clockwise reserved correction area and the counterclockwise reserved correction area. After the first weight removal, the dynamic balance of the fan blade to be corrected is re-measured. According to the pre-calibrated correspondence between the unbalance phase and the weight removal direction, and based on the offset direction of the re-measured residual unbalance phase relative to the center phase of the first weight removal pit, the clockwise reserved correction area or the counterclockwise reserved correction area is selected, and the subsequent weight removal position and subsequent weight removal amount are determined within the selected reserved correction area. If no candidate initial deduplication scheme is retained, the fan blade to be corrected is marked as exceeding the preset correction range, and the deduplication correction of the fan blade to be corrected is terminated.

[0007] In this invention, the clockwise and counterclockwise reserved correction amounts represent the minimum effective correction amounts required to reduce the corresponding expected residual imbalance to the allowable residual imbalance amount after determining the subsequent deduplication reference orientation based on the phase of the corresponding expected residual imbalance vector.

[0008] The effective correction amount of a certain subsequent deduplication pit is the component of the maximum allowable correction amount of the subsequent deduplication pit in the corresponding side's subsequent deduplication reference orientation. The remaining allowable correction amount on a certain side is the sum of the effective correction amounts of all subsequent deduplication pits that can be set on that side.

[0009] The reserved correction amount and the remaining allowable correction amount are used for screening the initial deduplication scheme. The actual subsequent deduplication location and subsequent deduplication amount are re-determined after the initial deduplication is completed and the residual unbalance vector is obtained.

[0010] Furthermore, the initial center imbalance vector, clockwise boundary imbalance vector, and counterclockwise boundary imbalance vector are obtained in the following manner: The unbalance quantity and unbalance phase obtained from each initial dynamic balance test are converted into the corresponding initial unbalance vector. The average value of the components of each initial unbalance vector in two mutually perpendicular directions is calculated, and the initial center unbalance vector is obtained based on the average value of the two components. Using the phase of the initial center unbalance vector as a reference, calculate the phase offset of each initial unbalance vector along the clockwise and counterclockwise directions respectively; The initial unbalance vector with the largest phase offset in the clockwise direction is taken as the initial clockwise boundary vector, and the initial unbalance vector with the largest phase offset in the counterclockwise direction is taken as the initial counterclockwise boundary vector. The clockwise angle transmission error, counterclockwise angle transmission error, and circumferential positioning error of the de-weighting position are obtained respectively during the process of the fan blade to be corrected being transferred from the dynamic balance detection position to the de-weighting position. The phase of the initial clockwise boundary vector is extended according to the clockwise angle transmission error and the circumferential positioning error to obtain the clockwise boundary imbalance vector; the phase of the initial counterclockwise boundary vector is extended according to the counterclockwise angle transmission error and the circumferential positioning error to obtain the counterclockwise boundary imbalance vector.

[0011] Furthermore, the remaining allowable correction amount on the candidate first deduplication pit side is calculated as follows: Based on the candidate first deduplication position and the candidate first deduplication weight, the arc segment of the pit opening occupied by the fan blade to be corrected along the pit edge of the candidate first deduplication pit is obtained. Within the allowable deduplication range on the side corresponding to the pit opening arc segment, the minimum allowable distance that needs to be retained between the candidate first deduplication pit and the adjacent deduplication pit or the boundary of the allowable deduplication range is deducted to obtain the effective machinable arc length on that side. The number of deduplication pits that this side can accommodate is determined based on the effective machinable arc length, the arc length of the opening of a single deduplication pit, and the minimum allowable distance between adjacent deduplication pits. Based on the maximum allowable pit volume at the location of each subsequent de-duplication pit, the material density of the blade to be corrected, and the distance from the center of each subsequent de-duplication pit to the rotation axis of the blade to be corrected, the maximum allowable correction amount of each subsequent de-duplication pit is obtained. According to the pre-defined correspondence between the unbalanced phase and the de-duplication orientation, the correction direction corresponding to each subsequent de-duplication pit is determined, and the effective correction amount of each subsequent de-duplication pit on the corresponding subsequent de-duplication reference orientation is obtained based on the phase difference between the correction direction and the corresponding subsequent de-duplication reference orientation. The effective correction amounts of each subsequent deduplication pit that can be accommodated on this side are added together to obtain the remaining allowable correction amount on this side.

[0012] Furthermore, when there are existing deduplication pits within the allowed deduplication range, the candidate initial deduplication scheme is set as follows: Obtain the pit opening range of each existing deduplication pit, and extend the minimum allowable distance from the pit opening boundary of each existing deduplication pit along both sides in the circumferential direction to form the occupied arc segment corresponding to each existing deduplication pit. When two or more existing deduplication slots overlap, the overlapping slots are merged into a single continuous slot. The starting point of the merged slot is the farthest point in the counterclockwise direction among the overlapping slots, and the ending point is the farthest point in the clockwise direction among the overlapping slots. The merged slot is then used as the actual unusable slot in that area.

[0013] The occupied arc segment is the continuous angular interval covered by extending the pit opening range of the existing deduplication pit to both sides along the circumferential direction with the minimum allowable distance. The pit opening range and the extended part together constitute the complete occupied arc segment of the existing deduplication pit. No position within this arc segment can be used as a candidate first deduplication position or subsequent deduplication position to ensure that the pit opening edge distance between the newly formed deduplication pit and the existing deduplication pit is not less than the minimum allowable distance.

[0014] Subtract each occupied arc segment from the allowed deduplication range to obtain the processable arc segment available for initial deduplication; Based on the phase of the initial center unbalance vector, candidate first deduplication positions are arranged at preset circumferential intervals within the machinable arc segment, and multiple candidate first deduplication weights are set for each candidate first deduplication position. A candidate first deduplication scheme consists of a candidate first deduplication location and a candidate first deduplication weight. The arc segment of the pit corresponding to the candidate first deduplication scheme is located within the processable arc segment, and the circumferential distance between it and the existing deduplication pit is not less than the minimum allowable distance.

[0015] Furthermore, the initial correction vector and the subsequent weight reduction are obtained as follows: For the same type of fan blade, perform weight reduction calibration at different weight reduction radii, record the weight reduction amount and the change in dynamic balance before and after weight reduction, and obtain the weight reduction conversion value corresponding to each weight reduction radius. Based on the candidate initial deduplication weight, the deduplication radius corresponding to the candidate initial deduplication position, and the deduplication conversion value of the deduplication radius, the initial correction vector corresponding to the candidate initial deduplication scheme is obtained; After the initial deduplication is completed, the actual correction vector generated by the initial deduplication is obtained based on the initial center unbalance vector and the remeasured residual unbalance vector, and the deduplication conversion value corresponding to the initial deduplication position is corrected based on the actual correction vector and the actual initial deduplication weight. The subsequent weight removal weight is calculated based on the remeasured residual imbalance, the weight removal radius corresponding to the subsequent weight removal position, and the corrected weight removal conversion value. Based on the subsequent weight removal and the effective machinable arc length of the selected reserved correction area, determine the number of subsequent weight removal pits and the weight removal of each subsequent weight removal pit.

[0016] Furthermore, before forming subsequent deduplication pits, the actual correction direction generated by the initial deduplication is verified: Record the actual center phase of the first de-weighting pit. According to the correspondence between the unbalanced phase and the de-weighting orientation, convert the phase of the actual correction vector to the circumferential reference of the fan blade, and calculate the phase deviation between the converted phase and the actual center phase of the first de-weighting pit. Subsequent deduplication must simultaneously meet the following requirements: the phase deviation is within the preset phase deviation range, and the remaining allowable correction amount of the selected reserved correction area is not less than the subsequent deduplication weight; If the phase deviation exceeds the preset phase deviation range, the subsequent deduplication is stopped, and the circumferential reference feature position of the fan blade to be corrected is reacquired. The reacquired circumferential reference feature position is compared with the circumferential reference feature position recorded before the initial dynamic balancing test to obtain the circumferential reference offset angle. The circumferential reference offset angle is used to correct the residual unbalance phase of the retest, and the actual correction vector and the phase deviation are recalculated. If the corrected phase deviation still exceeds the preset phase deviation range, the deduplication of the fan blade to be corrected is terminated; if the remaining allowable correction amount in the selected reserved correction area is less than the subsequent deduplication amount, the fan blade to be corrected is recorded as exceeding the preset correction range.

[0017] A fan blade dynamic balancing correction device includes a fan blade feeding module, a fan blade picking and flipping module, a fan blade angle identification module, a dynamic balancing initial measurement module, a milling deweighting module, a dynamic balancing re-measurement module, and a qualified fan blade receiving module. The fan blade angle recognition module, dynamic balance initial measurement module, milling deweight removal module, and dynamic balance re-measurement module are sequentially arranged along the correction flow direction of the fan blade; The blade picking and flipping module covers the blade feeding module, blade angle identification module, dynamic balance initial measurement module, milling de-weighting module, dynamic balance re-measurement module and qualified blade receiving module, and is used to grab, flip and transfer the blades. The fan blade angle recognition module is used to confirm the placement angle of the fan blade when it enters the dynamic balance preliminary measurement module. The dynamic balancing initial measurement module is used to obtain the unbalance amount and unbalance phase before the fan blades are deweighted. The milling de-weighting module is used to form de-weighting pits at corresponding positions on the fan blades according to the unbalance amount and unbalance phase. The dynamic balancing retest module is used to obtain the residual unbalance and residual unbalance phase after the formation of the de-weighting pit; The qualified fan blade receiving module is used to receive fan blades whose residual imbalance meets the qualified conditions.

[0018] Furthermore, the blade picking and flipping module sequentially transfers the blades in the blade feeding module to the blade angle recognition module, the dynamic balance initial measurement module, the milling de-weighting module, and the dynamic balance re-measurement module. When the residual imbalance obtained by the dynamic balancing retest module does not meet the qualified condition, the fan blade pick-up and flip module transfers the fan blade back to the milling and de-weighting module, and the milling and de-weighting module forms subsequent de-weighting pits on the fan blade. When the residual imbalance obtained by the dynamic balancing retest module reaches the qualified condition, the fan blade pick-up and flipping module transfers the fan blade to the qualified fan blade receiving module.

[0019] In summary, the present invention has the following beneficial effects: By determining the clockwise and counterclockwise boundary imbalance vectors based on multiple dynamic balancing tests before the initial deweighting, and comparing the reserved correction amount and the remaining allowable correction amount on both sides of each candidate initial deweighting scheme, the selected initial deweighting position retains processing allowances that match the needs of subsequent corrections. Furthermore, after retesting, the corresponding reserved correction area can be selected according to the offset direction of the residual imbalance phase to continue deweighting. This solves the problem that existing correction methods only focus on the initial deweighting effect, which can easily lead to insufficient space for subsequent deweighting and inability to continue correction due to the initial deweighting position occupying a key processing area. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the overall layout of the fan blade dynamic balancing correction device of the present invention; Figure 2 This is a flowchart of the fan blade dynamic balancing correction method of the present invention; Figure 3 This is a schematic diagram illustrating the determination of the initial center imbalance vector, clockwise boundary imbalance vector, and counterclockwise boundary imbalance vector in this invention. Figure 4 This is a schematic diagram illustrating the determination of the remaining allowable correction amount on both sides of the candidate first deduplication pit in this invention; Figure 5 This is a schematic diagram illustrating the setting of the candidate initial deduplication scheme when there are existing deduplication pits within the allowable deduplication range according to the present invention; Figure 6 This is a flowchart illustrating the calibration of the deduplication conversion value and the subsequent determination of the deduplication weight in this invention. Figure 7 This is a flowchart illustrating the selection of the reserved correction area and the verification of the actual correction direction after the initial deduplication in this invention. Figure 8 This is a schematic diagram showing the fan blade flow relationship between the modules in the correction device of the present invention.

[0022] In the picture: 1. Fan blade feeding module; 2. Fan blade picking, placing and flipping module; 3. Fan blade angle recognition module; 4. Dynamic balancing initial measurement module; 5. Milling deweighting module; 6. Dynamic balancing re-measurement module; 7. Qualified fan blade receiving module. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example: The following is in conjunction with the appendix Figure 1-8 The present invention will be described in further detail below.

[0025] Please see Figure 1-8This invention provides a technical solution: a method for dynamic balancing of fan blades and a corresponding calibration device, such as... Figure 2 , 3 As shown in Figure 4, the process includes: performing multiple initial dynamic balance tests on the fan blade to be corrected, converting the unbalance phase obtained from each test to the same circumferential reference of the fan blade, and obtaining the initial center unbalance vector, clockwise boundary unbalance vector, and counterclockwise boundary unbalance vector. Within the allowable deduplication range of the fan blade to be corrected, multiple candidate first deduplication schemes are set. Each candidate first deduplication scheme includes the candidate first deduplication position and the candidate first deduplication weight. Based on the initial correction vector corresponding to each candidate initial deduplication scheme, the expected residual unbalance vectors of the clockwise boundary unbalance vector and the counterclockwise boundary unbalance vector after initial correction are obtained respectively. Based on the phases of the two expected residual unbalance vectors, and according to the pre-calibrated correspondence between the unbalance phase and the deweighting azimuth, the clockwise side subsequent deweighting reference azimuth corresponding to the clockwise side expected residual unbalance vector and the counterclockwise side subsequent deweighting reference azimuth corresponding to the counterclockwise side expected residual unbalance vector are determined respectively. The portion of the expected residual unbalance exceeding the allowable residual unbalance is determined as the clockwise side reserved correction amount and the counterclockwise side reserved correction amount respectively. Based on the circumferential range occupied by the candidate first deduplication pit, the remaining allowable correction amount on the clockwise side of the candidate first deduplication pit in the subsequent deduplication reference position on the clockwise side, and the remaining allowable correction amount on the counterclockwise side in the subsequent deduplication reference position on the counterclockwise side are obtained respectively. The candidate first deduplication scheme in which the remaining allowable correction amount on both sides is not less than the corresponding side reserved correction amount is retained. It should be noted that each candidate initial deduplication scheme is set with different positions within the allowed deduplication range as the candidate initial deduplication position, and the calculations of each candidate scheme are independent of each other.

[0026] When a candidate scheme is excluded because the remaining allowable correction amount on both sides does not meet the reserved correction amount on the corresponding side, the candidate first deduplication position corresponding to the scheme does not actually form a deduplication pit. Therefore, it will not occupy any available space within the allowable deduplication range. Thus, there is no need to recalculate the remaining allowable correction amount on both sides of the remaining retained candidate schemes.

[0027] Calculate the difference between the remaining allowable correction amount and the corresponding reserved correction amount on both sides of each retained candidate first deduplication scheme. Compare the two differences of the same candidate first deduplication scheme and select the candidate first deduplication scheme with the largest smaller difference as the target first deduplication scheme. Complete the initial deduplication according to the target initial deduplication plan, and use the remaining processable range on the clockwise and counterclockwise sides of the initial deduplication pit as the clockwise reserved correction area and the counterclockwise reserved correction area, respectively. After the first weight removal, the dynamic balance of the fan blade to be corrected is re-measured. According to the pre-calibrated correspondence between the unbalance phase and the weight removal direction, and based on the offset direction of the re-measured residual unbalance phase relative to the center phase of the first weight removal pit, a clockwise or counterclockwise reserved correction area is selected. The subsequent weight removal position and subsequent weight removal amount are determined within the selected reserved correction area. Within the selected reserved correction area, determine the subsequent deduplication location, specifically as follows: First, based on the remeasured residual unbalance phase, determine the theoretical deduplication location corresponding to the remeasured residual unbalance phase according to the pre-calibrated correspondence between the unbalance phase and the deduplication direction; Then, within the selected reserved correction area, select the position that is closest to the theoretical deduplication orientation angle and whose pit opening edge distance between the first deduplication pit and the existing deduplication pit is not less than the minimum allowable distance as the subsequent deduplication position.

[0028] If there are multiple positions within the selected reserved correction area that meet the above spacing requirements, then the position whose angle is closest to the theoretical deduplication orientation is selected as the subsequent deduplication position, so as to achieve effective compensation of the subsequent correction amount with the minimum angle deviation.

[0029] In this embodiment, the remeasured residual unbalance phase is 82.5°, and the theoretical deduplication orientation corresponding to the remeasured residual unbalance phase is 85.5°. This position is located within the clockwise reserved correction area, and the distance between the pit opening edge and the first deduplication pit is 3.1mm, which meets the minimum allowable distance requirement. Therefore, 85.5° is selected as the subsequent deduplication position.

[0030] If no candidate initial deduplication scheme is retained, the fan blade to be calibrated will be marked as exceeding the preset calibration range, and the deduplication calibration of the fan blade to be calibrated will be terminated.

[0031] The initial center imbalance vector, clockwise boundary imbalance vector, and counterclockwise boundary imbalance vector are obtained as follows: The unbalance quantity and unbalance phase obtained from each initial dynamic balance test are converted into the corresponding initial unbalance vector. The average value of the components of each initial unbalance vector in two mutually perpendicular directions is calculated, and the initial center unbalance vector is obtained based on the average value of the two components. Using the phase of the initial central unbalance vector as a reference, calculate the phase offset of each initial unbalance vector along the clockwise and counterclockwise directions respectively; The initial unbalance vector with the largest phase offset in the clockwise direction is taken as the initial clockwise boundary vector, and the initial unbalance vector with the largest phase offset in the counterclockwise direction is taken as the initial counterclockwise boundary vector. The clockwise angle transmission error, counterclockwise angle transmission error, and circumferential positioning error of the de-weighting position are obtained respectively during the process of the fan blade to be corrected being transferred from the dynamic balance detection position to the de-weighting position. By extending the phase of the initial clockwise boundary vector according to the clockwise angle transmission error and the circumferential positioning error, the clockwise boundary imbalance vector is obtained; by extending the phase of the initial counterclockwise boundary vector according to the counterclockwise angle transmission error and the circumferential positioning error, the counterclockwise boundary imbalance vector is obtained. In this embodiment, an aluminum alloy fan blade with an outer diameter of 260mm is used as the calibration target. The fan blade hub is equipped with an annular weight-reducing belt with a weight-reducing radius of 112mm and a material density of 2.70×10⁻⁶. -3 g / mm 3 The residual imbalance is allowed to be 0.80 g·mm according to the product technical requirements of this type of fan blade.

[0032] The de-weighting process uses a 6mm diameter flat end mill, with a maximum depth of 0.75mm for a single de-weighting pit and a minimum distance of 3mm between the edges of adjacent de-weighting pits.

[0033] The determination of the distance between the edges of adjacent de-weighting pits needs to take into account the diameter of the de-weighting tool, the minimum remaining wall thickness requirement of the fan blade hub in the de-weighting area, and the mutual influence range of material removal between adjacent pits during milling.

[0034] In this embodiment, a 6mm diameter flat-bottom end mill is used for deweighting. Finite element strength verification and milling process test were conducted on the same type of aluminum alloy fan blade hub structure. When the distance between the edges of the pits is less than 3mm, the remaining material thickness between adjacent deweighting pits is insufficient to meet the structural strength requirements of the hub at the highest working speed. Moreover, during the milling process, the insufficient local stiffness of the material can easily cause machining deformation and mutual interference, affecting the dimensional accuracy and correction effect of the deweighting pits.

[0035] The positioning notch on the fan blade hub is selected as the circumferential reference. The center line of the positioning notch is recorded as 0°. The unbalance phase and weight removal position are recorded along the fan blade rotation direction.

[0036] The dynamic balancing tester outputs the unbalanced phase of the fan blade, and the unbalanced phase obtained is at the same circumferential angle as the material removal position.

[0037] The fan blade to be calibrated was tested three times in a continuous manner with the clamping state unchanged. The resulting unbalance and unbalance phase were 9.62 g·mm and 81.3°, 9.48 g·mm and 82.8°, and 9.71 g·mm and 80.7°, respectively.

[0038] During data processing, the imbalance obtained from each detection is converted into components in two mutually perpendicular directions according to the corresponding phase. The average value of the components in the same direction is calculated, and the two average components are then combined to form the initial central imbalance vector.

[0039] The initial center imbalance is 9.60 g·mm, and the center phase is 81.6°.

[0040] With the center phase of 81.6° as the reference, the maximum detection offset in the clockwise direction is 1.2° and the maximum detection offset in the counterclockwise direction is 0.9°.

[0041] Before formal calibration, the same type of fan blade was used to move back and forth between the dynamic balance test position and the weight removal position 10 times. The clockwise angle transmission error was measured to be 0.6°, the counterclockwise angle transmission error was 0.9°, and the circumferential positioning error of the weight removal position was 0.3°.

[0042] The clockwise boundary phase is obtained by extending 82.8° by 0.9° in the clockwise direction, and the clockwise boundary imbalance vector is taken as 9.48 g·mm and 83.7°.

[0043] The counterclockwise boundary phase is obtained by extending 80.7° by 1.2° in the counterclockwise direction, and the counterclockwise boundary imbalance vector is taken as 9.71 g·mm and 79.5°.

[0044] During the boundary phase expansion process, only the phase is adjusted, and the boundary imbalance amount still adopts the imbalance amount in the corresponding initial detection result.

[0045] The clockwise and counterclockwise boundary imbalance vectors are used to characterize the phase boundaries that may appear during multiple detection results and angle transmission. The boundary imbalance amount is the measured imbalance amount in the corresponding boundary detection results, and is not used as the upper limit of the imbalance amount in all detection results.

[0046] Based on the processable range of the deweighting zone, three candidate initial deweighting schemes are set near the center phase. Scheme A has a deweighting position of 80.9° and a candidate deweighting amount of 0.050g, Scheme B has a deweighting position of 81.6° and a candidate deweighting amount of 0.052g, and Scheme C has a deweighting position of 82.3° and a candidate deweighting amount of 0.050g.

[0047] The initial correction value for schemes A and C is 5.60 g·mm, and the initial correction value for scheme B is 5.82 g·mm.

[0048] The expected residual imbalance is obtained by component subtraction. First, the boundary imbalance vector and the initial correction vector are converted into components in two mutually perpendicular directions. Then, the correction components in the corresponding directions are subtracted. Finally, the remaining components are converted into the expected residual imbalance and the expected residual imbalance phase.

[0049] The clockwise and counterclockwise reserved correction amounts are respectively taken as the portion of the expected residual imbalance in the corresponding direction that exceeds 0.80 g·mm.

[0050] The remaining allowable correction amount on both sides of each candidate initial de-duplication pit is obtained based on the remaining machinable arc length, pit opening arc length, minimum allowable spacing, allowable pit depth, and de-duplication radius.

[0051] The comparison results of each candidate initial deduplication scheme are shown in Table 1.

[0052] The remaining allowable correction amounts on the clockwise and counterclockwise sides in Table 1 are obtained by summing the effective correction amounts of each configurable subsequent deduplication pit on the corresponding side's subsequent deduplication reference orientation.

[0053] The effective correction amount for each subsequent deduplication pit is determined based on the maximum allowable correction amount of the pit and the phase difference between its correction direction and the corresponding subsequent deduplication reference orientation.

[0054] Table 1: Comparison Results of Candidate Initial Deduplication Schemes The remaining allowable correction amounts on both sides of the three candidate schemes can meet the reserved correction requirements in the corresponding directions.

[0055] The smaller of the two differences in Scheme A is 0.75 g·mm, which is greater than 0.40 g·mm in Scheme B and 0.52 g·mm in Scheme C. Therefore, Scheme A is selected as the target initial deduplication scheme.

[0056] If no candidate solution is found that can meet the reserved correction requirements on both sides, the current fan blade will not be milled and will be recorded as exceeding the preset correction range.

[0057] According to scheme A, the first de-weighting pit is formed at 80.9°. The milling depth is set to 0.66mm, the actual pit depth is 0.65mm, and the actual removed mass is 0.049g.

[0058] The actual initial weight reduction is calculated based on the tool diameter, actual feed depth, and shape of the weight reduction pit recorded by the milling weight reduction module. The actual pit volume is then converted based on the material density of the fan blade to be corrected. If weighing conditions are available, the weight difference of the fan blade before and after the initial weight reduction can also be used for verification.

[0059] The opening of the first de-weighting pit occupies 79.4° to 82.4° circumferentially. Combining the minimum allowable spacing of 3mm and the machinable boundary of the de-weighting zone, 85.5° to 94.7° is designated as the clockwise reserved correction zone, and 67.0° to 76.3° is designated as the counterclockwise reserved correction zone.

[0060] The residual imbalance after the first deweighting was 4.12 g·mm, and the phase of the residual imbalance was 82.5°.

[0061] The residual unbalanced phase after retesting is shifted clockwise relative to the center phase of the initial deduplication pit. Therefore, the subsequent deduplication position is selected from the clockwise reserved correction area.

[0062] The subsequent de-weighting position is set at 85.5°, the subsequent de-weighting mass is set at 0.0304g, and the subsequent de-weighting pit processing depth is set at 0.40mm.

[0063] The distance between the edges of the subsequent de-duplication pit and the initial de-duplication pit is 3.1mm, which meets the minimum allowable distance requirement.

[0064] The residual imbalance after subsequent weight removal is 0.74 g·mm, which is lower than the allowable residual imbalance of 0.80 g·mm.

[0065] like Figure 5 As shown, the remaining allowable correction amount on one side of the candidate initial deduplication pit is calculated as follows: Based on the candidate first deduplication position and the candidate first deduplication weight, the arc segment of the pit opening occupied by the fan blade to be corrected along the pit edge of the candidate first deduplication pit is obtained. Within the allowable deduplication range on the corresponding side of the pit opening arc segment, the minimum allowable distance that needs to be retained between the candidate first deduplication pit and the adjacent deduplication pit or the boundary of the allowable deduplication range is deducted to obtain the effective machinable arc length on that side. The number of deduplication pits that can be accommodated on this side can be determined based on the effective machinable arc length, the arc length of the opening of a single deduplication pit, and the minimum allowable distance between adjacent deduplication pits. Based on the maximum allowable pit volume at the location of each subsequent de-duplication pit, the material density of the blade to be corrected, and the distance from the center of each subsequent de-duplication pit to the rotation axis of the blade to be corrected, the maximum allowable correction amount of each subsequent de-duplication pit is obtained. According to the pre-defined correspondence between the unbalanced phase and the de-duplication orientation, the correction direction corresponding to each subsequent de-duplication pit is determined, and the effective correction amount of each subsequent de-duplication pit on the corresponding subsequent de-duplication reference orientation is obtained based on the phase difference between the correction direction and the corresponding subsequent de-duplication reference orientation. The effective correction amounts of each subsequent deduplication pit that can be accommodated on this side are added together to obtain the remaining allowable correction amount on this side.

[0066] Wherein, the maximum allowable correction amount for a certain subsequent deduplication pit is . Its correction direction is related to the subsequent deduplication reference orientation on the corresponding side. The phase difference is The effective correction amount for the pit is: .

[0067] The remaining allowable correction amount on a certain side is the sum of the effective correction amounts of all subsequent deduplication pits that can be set on that side.

[0068] When existing deduplication slots exist within the allowed deduplication range, the candidate initial deduplication scheme should be set as follows: Obtain the pit opening range of each existing deduplication pit, and extend the minimum allowable distance from the pit opening boundary of each existing deduplication pit along both sides in the circumferential direction to form the occupied arc segment corresponding to each existing deduplication pit. Subtract each occupied arc segment from the allowed deduplication range to obtain the processable arc segments available for initial deduplication; Based on the phase of the initial center unbalance vector, candidate first deduplication positions are arranged at preset circumferential intervals within the machinable arc segment, and multiple candidate first deduplication weights are set for each candidate first deduplication position. A candidate first deduplication scheme consists of a candidate first deduplication location and a candidate first deduplication weight. The arc segment of the pit corresponding to the candidate first deduplication scheme is located within the processable arc segment, and the circumferential distance between it and the existing deduplication pit is not less than the minimum allowable distance.

[0069] In this embodiment: when a fan blade of the same model that has already formed a deduplication pit re-enters the calibration process, the center position, pit opening range and pit depth of the existing deduplication pit are first obtained.

[0070] In this specific embodiment, the allowable deduplication range is 50° to 115°. The center position of the first existing deduplication pit is 70.0°, the pit opening diameter is 6.1mm, and the pit depth is 0.31mm. The center position of the second existing deduplication pit is 96.0°, the pit opening diameter is 6.0mm, and the pit depth is 0.28mm.

[0071] Based on a de-weighting radius of 112mm, the arc of the pit opening of the first existing de-weighting pit is 68.4° to 71.6°, and the arc of the pit opening of the second existing de-weighting pit is 94.5° to 97.5°.

[0072] After converting the minimum allowable spacing of 3mm into a circumferential interval of 1.5°, the occupied arc segment corresponding to the first existing deduplication pit is 66.9° to 73.1°, and the occupied arc segment corresponding to the second existing deduplication pit is 92.9° to 99.1°.

[0073] After deducting the two occupied arc segments from the allowable deduplication range, the remaining machinable arc segments are 50.0° to 66.9°, 73.1° to 92.9°, and 99.1° to 115.0°, respectively.

[0074] Based on the phase of the initial center unbalanced vector, candidate first deduplication positions are arranged at 1.5° intervals within each machinable arc segment.

[0075] If the opening range of a candidate deduplication pit exceeds the boundary of the machinable arc segment, the candidate position will not be retained.

[0076] Taking a candidate first deduplication pit with a center position of 81.9° as an example, its pit opening arc ranges from 80.4° to 83.4°, and the occupied range after taking into account the minimum allowable spacing is from 78.9° to 84.9°.

[0077] The available arcs on the counterclockwise side of the candidate first de-cracking pit are 50.0° to 66.9° and 73.1° to 78.9°.

[0078] An arc segment of 50.0° to 66.9° can accommodate three subsequent deduplication pits, while an arc segment of 73.1° to 78.9° is insufficient to accommodate a complete deduplication pit while preserving the distance between the two ends.

[0079] The maximum permissible depths of the three counterclockwise side subsequent de-duplication pits are 0.24 mm, 0.23 mm and 0.22 mm respectively, and the corresponding maximum permissible correction amounts are 2.05 g·mm, 1.97 g·mm and 1.88 g·mm respectively.

[0080] The remaining allowable correction amount on the counterclockwise side of the candidate position is 5.90 g·mm.

[0081] The available arcs on the clockwise side of the candidate initial deduplication pit are 84.9° to 92.9° and 99.1° to 115.0°, and the two arc lengths can accommodate a total of 4 subsequent deduplication pits.

[0082] The maximum permissible depths of the four clockwise side de-duplication pits are 0.20 mm, 0.21 mm, 0.20 mm and 0.19 mm, respectively, and the corresponding maximum permissible correction amounts are 1.71 g·mm, 1.79 g·mm, 1.71 g·mm and 1.62 g·mm, respectively.

[0083] The remaining allowable correction amount on the clockwise side of the candidate position is 6.83 g·mm.

[0084] For other candidate initial deduplication positions, the occupied arc segment of the existing deduplication pit is deducted in the same way, and the number of deduplication pits that can be accommodated on the clockwise side and the counterclockwise side and the remaining allowable correction amount are calculated respectively.

[0085] If the distance between the edge of the candidate first de-duplication pit and the existing de-duplication pit is less than 3mm, or if the pit opening of the candidate first de-duplication pit exceeds the machinable arc segment, the candidate first de-duplication scheme will not be included in the subsequent comparison.

[0086] The preset circumferential interval is determined based on the minimum positioning resolution of the circumferential turntable, the width of the pit angle formed by the de-weighting tool at the corresponding de-weighting radius, and the calculation amount of the candidate scheme. The preset circumferential interval is not less than the minimum positioning resolution of the circumferential turntable.

[0087] The candidate initial weight removal is set between zero and the maximum allowable weight removal for a single weight removal pit, and is arranged in ascending order of the removal mass corresponding to the minimum feed rate of the milling part.

[0088] This allows the candidate initial deduplication scheme to cover the actual deduplication locations and amounts that the equipment can perform.

[0089] like Figure 6 As shown, the initial correction vector and subsequent weight reduction are obtained as follows: For the same type of fan blade, perform weight reduction calibration at different weight reduction radii, record the weight reduction amount and the change in dynamic balance before and after weight reduction, and obtain the weight reduction conversion value corresponding to each weight reduction radius. Based on the candidate initial deduplication weight, the deduplication radius corresponding to the candidate initial deduplication position, and the deduplication conversion value of the deduplication radius, the initial correction vector corresponding to the candidate initial deduplication scheme is obtained; After the initial deduplication is completed, the actual correction vector generated by the initial deduplication is obtained based on the initial center unbalance vector and the remeasured residual unbalance vector. The deduplication conversion value corresponding to the initial deduplication position is then corrected based on the actual correction vector and the actual initial deduplication weight. Based on the remeasured residual unbalance phase, and according to the correspondence between the unbalance phase and the deduplication direction, the subsequent deduplication position is determined within the selected reserved correction area, and the phase difference between the correction direction corresponding to the subsequent deduplication position and the remeasured residual unbalance vector direction is determined. The subsequent weight of deweighting is calculated based on the portion of the residual imbalance exceeding the allowable residual imbalance, the phase difference, the deweighting radius corresponding to the subsequent deweighting position, and the corrected deweighting conversion value. Based on the subsequent weight removal and the effective machinable arc length of the selected reserved correction area, determine the number of subsequent weight removal pits and the weight removal of each subsequent weight removal pit; When there is a phase difference between the correction direction corresponding to the subsequent deweighting position and the direction of the remeasured residual unbalance vector, the correction amount corresponding to the subsequent deweighting position is converted into an effective correction amount along the direction of the remeasured residual unbalance vector according to the phase difference, and the subsequent deweighting amount is determined accordingly.

[0090] Based on the subsequent weight removal and the effective machinable arc length of the selected reserved correction area, determine the number of subsequent weight removal pits and the weight removal of each subsequent weight removal pit; In this embodiment, the deweight conversion value is calibrated before the formal calibration of the same type of fan blade. The fan blade used for calibration and the fan blade to be calibrated use the same material, the same hub structure and the same deweight belt size.

[0091] In this specific implementation, six fan blades from the same batch were selected, and two fan blades were used for calibration at three weight-reduction radii of 105mm, 112mm, and 118mm.

[0092] During the calibration process, the actual removal mass and the change in imbalance before and after weight removal were recorded. The calibration results are shown in Table 2.

[0093] Table 2: De-duplication calibration results for different de-duplication radii When the candidate initial deweighting position is located at a deweighting radius of 112 mm, the initial estimate is made according to a correction amount of 0.1120 g·mm for every 0.001 g of material removed.

[0094] The candidate weight reduction for Scheme A is 0.050g, and the corresponding expected initial correction amount is 5.60g·mm.

[0095] After the initial deweighting, the actual correction amount obtained from the initial center unbalance vector and the remeasured residual unbalance vector was 5.48 g·mm, and the actual removed mass was 0.049 g.

[0096] The actual correction amount generated by removing 0.001g of material from the fan blades is 0.1118g·mm, and this value is used for subsequent weight calculations.

[0097] The residual imbalance was measured to be 4.12 g·mm. After selecting 85.5° as the subsequent weight reduction position, a subsequent correction amount of approximately 3.40 g·mm is required.

[0098] The calculation is based on the fact that 0.1118 g·mm correction is generated for every 0.001 g of material removed, and the subsequent removal mass is taken as 0.0304 g.

[0099] The volume to be removed for 0.0304g of material is 11.26mm³. When machining with a 6mm diameter flat-bottom end mill, the pit depth is 0.40mm.

[0100] The weight removed in this subsequent process is less than the maximum allowable weight removed by a single weight removal pit, so a single subsequent weight removal pit will be used to complete the processing.

[0101] When the subsequent weight removal exceeds the maximum allowable weight removal of a single weight removal pit, the number of weight removal pits that can be set is first determined based on the effective machinable arc length of the target reserved correction area, and then the subsequent weight removal is allocated to each weight removal pit.

[0102] The depth of each subsequent deduplication pit shall not exceed 0.75 mm, and the distance between the pit opening edges of adjacent subsequent deduplication pits and between subsequent deduplication pits and existing deduplication pits shall not be less than 3 mm.

[0103] like Figure 7 As shown, the actual correction direction generated by the first deduplication is verified before the formation of subsequent deduplication pits: Record the actual center phase of the first de-balance pit. According to the correspondence between the unbalanced phase and the de-balance orientation, convert the phase of the actual correction vector to the circumferential reference of the fan blade, and calculate the phase deviation between the converted phase and the actual center phase of the first de-balance pit. Subsequent deduplication must simultaneously meet the following requirements: the phase deviation is within the preset phase deviation range, and the remaining allowable correction amount of the selected reserved correction area is not less than the subsequent deduplication weight; If the phase deviation exceeds the preset phase deviation range, stop the subsequent deduplication and reacquire the circumferential reference feature position of the fan blade to be corrected; The reacquired circumferential reference feature position is compared with the circumferential reference feature position recorded before the initial dynamic balancing test to obtain the circumferential reference offset angle. The circumferential reference offset angle is used to correct the residual unbalance phase of the remeasurement, and the actual correction vector and phase deviation are recalculated. If the corrected phase deviation still exceeds the preset phase deviation range, the deduplication of the fan blade to be corrected will be terminated; if the remaining allowable correction amount in the selected reserved correction area is less than the subsequent deduplication amount, the fan blade to be corrected will be recorded as exceeding the preset correction range. In this embodiment, the allowable phase deviation in the first de-weighting direction is taken as 1.5° based on the repeated clamping and transfer calibration results of the same type of fan blade.

[0104] In this specific embodiment, the actual correction amount corresponding to the difference between the initial center unbalance vector and the residual unbalance vector after the first deduplication is 5.48 g·mm, and the actual correction phase is 80.92°.

[0105] The actual center phase of the first deduplication pit is 80.9°, and the deviation between the actual corrected phase and the center phase of the first deduplication pit is 0.02°.

[0106] The phase deviation did not exceed 1.5°, and the remaining allowable correction amount in the clockwise reserved correction area was sufficient to meet the subsequent correction requirements of 3.40 g·mm. Therefore, the subsequent deduplication was continued.

[0107] Another fan blade in the same production batch showed an abnormal phase deviation after the first deweighting. The phase at the center of the first deweighting pit was 78.6°, and the actual corrected phase obtained from the initial and retest results was 81.1°.

[0108] The phase deviation of the fan blade is 2.5°, and subsequent deduplication will not be carried out for the time being.

[0109] After re-acquiring the position of the blade positioning notch, the phase of the positioning notch recorded before the initial dynamic balance test was 0.2°, and the phase of the positioning notch obtained again was 1.9°.

[0110] The circumferential reference offset angle between the two positioning notch positions is 1.7°, and the residual unbalance phase of the remeasurement is corrected according to this offset angle.

[0111] The corrected phase was 79.4°, which deviated from the initial deduplication pit center phase by 0.8°.

[0112] The corrected phase deviation is within the allowable range of 1.5°, and the remaining allowable correction amount in the target reserved correction area can meet the subsequent deduplication needs. Therefore, the fan blade continues to undergo subsequent deduplication.

[0113] Fan blades whose phase deviation still exceeds 1.5° after recalibrating the circumferential reference will no longer be milled and will be recorded as phase verification abnormalities.

[0114] If the remaining allowable correction amount in the target reserved correction zone is less than the subsequent weight reduction of the fan blades, milling will not continue, and it will be recorded as exceeding the preset correction range.

[0115] like Figure 1 and 8 As shown, the components include: a blade feeding module 1, a blade picking and flipping module 2, a blade angle recognition module 3, a dynamic balance initial measurement module 4, a milling weight removal module 5, a dynamic balance re-measurement module 6, a qualified blade receiving module 7, and a calibration control unit. The fan blade angle recognition module 3, the dynamic balance initial measurement module 4, the milling deweight removal module 5, and the dynamic balance re-measurement module 6 are set sequentially along the correction flow direction of the fan blade; The blade picking and flipping module 2 covers the blade feeding module 1, blade angle identification module 3, dynamic balance initial measurement module 4, milling weight removal module 5, dynamic balance re-measurement module 6, and qualified blade receiving module 7, and is used to grab, flip, and transfer the blades. The blade angle recognition module 3 is used to confirm the placement angle of the blades when they enter the dynamic balance preliminary measurement module 4; The dynamic balancing initial measurement module 4 is used to obtain the unbalance amount and unbalance phase before the fan blades are ballasted. The milling de-weighting module 5 is used to form de-weighting pits at the corresponding positions of the fan blades according to the amount and phase of the imbalance. The dynamic balancing retest module 6 is used to obtain the residual unbalance and residual unbalance phase after the formation of the de-weighting pit; The qualified fan blade receiving module 7 is used to receive fan blades whose residual imbalance meets the qualified conditions.

[0116] The fan blade picking and flipping module 2 sequentially transfers the fan blades in the fan blade feeding module 1 to the fan blade angle recognition module 3, the dynamic balance initial measurement module 4, the milling deweight removal module 5, and the dynamic balance re-measurement module 6. When the residual imbalance obtained by the dynamic balancing retest module 6 does not meet the qualified conditions, the fan blade pick-up and flip module 2 transfers the fan blade back to the milling and weight removal module 5, and the milling and weight removal module 5 forms subsequent weight removal pits on the fan blade. When the residual imbalance obtained by the dynamic balance retest module 6 does not meet the qualified condition, the correction control unit verifies the actual correction direction generated by the first weight removal. When the phase deviation of the actual correction direction is within the preset phase deviation range, and the remaining allowable correction amount of the selected reserved correction area is not less than the subsequent weight removal, the fan blade pick-up and flip module 2 transfers the fan blade back to the milling weight removal module 5, and the milling weight removal module 5 forms the subsequent weight removal pit. When the phase deviation of the actual correction direction exceeds the preset phase deviation range, the fan blade pick-up and flip module 2 transfers the fan blade to the fan blade angle recognition module 3 and reacquires the circumferential reference feature position of the fan blade; if the corrected phase deviation still exceeds the preset phase deviation range, or if the remaining allowable correction amount of the selected reserved correction area is less than the subsequent weight reduction, the correction control unit stops continuing to reduce the weight of the fan blade and outputs an abnormality flag. When the residual imbalance obtained by the dynamic balance retest module 6 reaches the qualified condition, the fan blade pick-up and flip module 2 transfers the fan blade to the qualified fan blade receiving module 7. The correction control unit is connected to the blade angle identification module 3, the dynamic balancing initial measurement module 4, the milling deweighting module 5, and the dynamic balancing re-measurement module 6, respectively. It is used to receive multiple initial dynamic balancing test results, determine the clockwise boundary imbalance vector and the counterclockwise boundary imbalance vector, compare the reserved correction amount and the remaining allowable correction amount on both sides of each candidate first deweighting scheme, determine the target first deweighting scheme, and output the first deweighting position and the first deweighting amount to the milling deweighting module 5. The correction control unit is also used to select the corresponding reserved correction area according to the residual imbalance phase obtained by the dynamic balancing re-measurement module 6, and output the subsequent deweighting position and the subsequent deweighting amount to the milling deweighting module 5.

[0117] In this embodiment, the fan blade feeding module 1 to be inspected adopts a horizontally arranged feeding tray with multiple fan blade placement slots spaced apart on the feeding tray. The fan blade to be corrected is placed in the fan blade placement slot with the hub facing upward.

[0118] The fan blade picking and flipping module 2 uses a six-axis robot arm. The end of the robot arm is equipped with a two-finger gripper. The gripper clamps the fan blade from both sides of the inner hole of the fan blade hub, avoiding the positioning notch and the area where weight can be removed.

[0119] After the equipment is installed, the robot arm is taught to the feeding tray, angle recognition position, initial measurement fixture, milling fixture, re-measurement fixture and receiving tray respectively, and the gripping height, placement height, gripper opening and closing distance and robot wrist rotation angle corresponding to each position are saved.

[0120] The fan blade angle recognition module 3 includes an industrial camera and a ring light. The industrial camera is installed above the fan blade hub, and the ring light is positioned between the industrial camera and the fan blade.

[0121] The industrial camera's acquisition range covers the outer circumference of the wheel hub and the positioning notch on the wheel hub, while the ring illumination element is used to reduce the impact of wheel hub surface reflection on the edge recognition of the positioning notch.

[0122] Before the equipment is put into use, a circular calibration piece with circumferential engravings is placed at the angle recognition position, so that the center of the calibration piece coincides with the placement center of the fan blade hub, and the correspondence between the image angle and the fan blade circumferential angle is determined according to the circumferential engravings on the calibration piece.

[0123] After the robotic arm places the fan blade to be corrected at the angle recognition position, the industrial camera acquires an image of the hub and uses the center line between the two edges of the positioning notch as the angle reference for the fan blade.

[0124] When the center line of the positioning notch deviates from the predetermined direction, the robot arm re-grips the fan blade and rotates it by the corresponding angle until the center line of the positioning notch enters the preset angle range.

[0125] This embodiment uses aluminum alloy fan blades with an outer diameter of 260mm. The annular weight-reducing area on the fan blades is located 112mm from the axis of rotation. The density of the fan blade material is 2.70×10⁻⁶. -3 g / mm³, with an allowable residual imbalance of 0.80 g·mm.

[0126] The determination of permissible residual imbalance shall be based on the currently effective international standard ISO 21940-11 "Mechanical vibration rotor balancing - Part 11: Procedures and tolerances for rigid rotors" and the national standard GB / T 9239.1 "Quality requirements for mechanical vibration constant-state (rigid) rotor balancing".

[0127] In this embodiment, the fan blades are rigid rotors with a maximum operating speed of 1200 r / min. Referring to the balance quality level recommendations for fan rotors in ISO 1940-1, the balance quality level G6.3 is selected. The allowable residual imbalance is calculated to be approximately 0.78 g·mm using the allowable imbalance calculation method corresponding to this balance quality level. After rounding, 0.80 g·mm is taken as the allowable residual imbalance in this embodiment.

[0128] Before the equipment is put into use, the amplitude and phase of the initial dynamic balance test module and the re-dynamic balance test module are calibrated using the same standard rotor to determine the amplitude correction coefficient and phase zero-point deviation between the two test modules.

[0129] The residual unbalance and residual unbalance phase output by the dynamic balancing retest module are converted to the same detection benchmark as the initial dynamic balancing test module according to the amplitude correction coefficient and phase zero deviation, and then vector operations are performed with the initial center unbalance vector.

[0130] The dynamic balancing initial test module 4 uses a dynamic balancing test machine that can output the unbalance quantity and unbalance phase. The test fixture of the dynamic balancing test machine includes a hub support shaft and an axial clamping component.

[0131] The hub support shaft restricts the radial position of the fan blades, the axial clamping component restricts the axial movement of the fan blades during the testing process, and the angle mark on the testing fixture maintains a predetermined correspondence with the center line of the positioning notch.

[0132] After the fan blades are installed, the dynamic balancing testing machine drives the fan blades to rotate at 1200 r / min, and collects vibration signals and speed reference signals within 8 seconds after the speed stabilizes.

[0133] The same blade was tested three times consecutively without being unclamped, and the resulting unbalance values ​​and phases were 9.58 g·mm and 81.4°, 9.63 g·mm and 81.9°, and 9.55 g·mm and 81.2°, respectively.

[0134] After converting the three test results to the same angular reference, the initial center imbalance of the fan blade was found to be 9.59 g·mm, and the initial center imbalance phase was 81.5°.

[0135] The milling de-weighting module 5 includes a machining fixture, a circumferential rotary table, and a vertical milling component. The machining fixture is fixed on the circumferential rotary table, and the vertical milling component is located above the machining fixture.

[0136] The machining fixture is equipped with angle marks corresponding to the positioning notch. After the fan blade is installed in the machining fixture, the center line of the positioning notch and the zero position of the circumferential turntable maintain a fixed angle relationship.

[0137] Before formal calibration, based on the three-dimensional structure of the hub of the same type of fan blade, the local wall thickness at each circumferential position, and the minimum remaining wall thickness to be retained after weight removal, the maximum allowable pit depth and the maximum allowable pit volume at each circumferential position within the allowable weight removal range are determined, and a correspondence table between the weight removal position and the maximum allowable pit depth is formed.

[0138] When calculating the remaining allowable correction amount on each side, the maximum allowable pit volume for each subsequent deduplication position is read from the corresponding table.

[0139] This machining process uses a 6mm diameter flat end mill, a spindle speed of 12000r / min, a downward feed rate of 60mm / min, and a maximum allowable depth of 0.75mm for a single de-duplication pit.

[0140] The robotic arm places the fan blades, after initial measurement, into the machining fixture. The circumferential turntable rotates the fan blades to the initial weight-removal position of 81.0°. After the machining fixture locks the fan blades, the milling cutter feeds downwards by 0.65mm from a safe position above the hub surface.

[0141] Based on the milling cutter diameter, feed depth, and blade material density, the initial mass removal is estimated to be approximately 0.0496 g, and the correction amount formed at the 112 mm removal radius is approximately 5.56 g·mm.

[0142] After the initial weight reduction is completed, the milling cutter first retracts to a safe position, the machining fixture is then released from clamping, and the robot arm sends the fan blade into the dynamic balancing retest module 6.

[0143] The dynamic balancing retest module 6 uses the same type of dynamic balancing testing machine as the dynamic balancing initial test module 4. The retest fixture uses the same hub support method and angle reference, and the test speed and sampling time are also consistent with the initial test.

[0144] The results of the three retests after the initial deduplication were 4.06 g·mm and 82.0°, 4.02 g·mm and 82.4°, and 4.05 g·mm and 82.1°, respectively.

[0145] After converting the results of the three retests to the same angular reference, the residual unbalance was found to be 4.04 g·mm, and the residual unbalance phase was 82.2°.

[0146] Since 4.04 g·mm is greater than 0.80 g·mm, the robot arm sends the fan blade back to the milling and weight removal module 5.

[0147] After the robot arm reloads the fan blades into the machining fixture, the circumferential turntable rotates the fan blades to the subsequent weight removal position at 85.7°. The milling cutter feeds downwards by 0.40mm and forms the subsequent weight removal pit.

[0148] The center angle interval between the first and subsequent de-duplication pits is 4.7°, and the corresponding center arc length at the 112mm de-duplication radius is approximately 9.19mm.

[0149] Both de-weighting pits were machined using a 6mm diameter milling cutter. The distance between the edges of the pits was approximately 3.19mm, which is greater than the minimum allowable distance of 3mm.

[0150] Based on the milling cutter diameter, subsequent feed depth, and blade material density, the subsequent mass removal is estimated to be approximately 0.0305g, and the correction amount formed at the 112mm deweighting radius is approximately 3.42g·mm.

[0151] After the subsequent weight reduction was completed, the robotic arm sent the fan blades back into the dynamic balancing retest module 6. The final test results for the three tests were 0.66 g·mm and 63.5°, 0.68 g·mm and 64.1°, and 0.67 g·mm and 63.8°, respectively.

[0152] The vector average of the three final measurements was approximately 0.67 g·mm and 63.8°, which is lower than the allowable residual imbalance of 0.80 g·mm.

[0153] The qualified fan blade receiving module 7 uses a receiving tray that is separate from the feeding tray. The receiving tray is equipped with multiple fan blade receiving slots. The robot arm puts the fan blades that have passed the final test into the empty fan blade receiving slots.

[0154] If the remeasured residual imbalance is still greater than the allowable residual imbalance, first check whether there are still processing positions within the allowable deweighting area that meet the requirements for pit spacing and maximum pit depth.

[0155] When a suitable processing position is found, the robot arm sends the fan blade back into the milling and weight removal module 5. When no suitable processing position is found, processing stops and the fan blade is removed from the flow area of ​​qualified fan blades.

[0156] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0157] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A method for dynamic balancing correction of fan blades, characterized in that, include: Multiple initial dynamic balance tests were performed on the fan blade to be corrected. The results of each test were converted to the same circumferential reference of the fan blade to obtain the initial center unbalance vector, clockwise boundary unbalance vector and counterclockwise boundary unbalance vector. Multiple candidate first-time de-weighting schemes are set within the allowable de-weighting range of the fan blade to be corrected. Each candidate first-time de-weighting scheme includes a candidate first-time de-weighting position and a candidate first-time de-weighting amount. Based on the initial correction vector corresponding to each candidate initial deduplication scheme, the expected residual unbalance vectors after the initial correction of the clockwise boundary unbalance vector and the counterclockwise boundary unbalance vector are obtained respectively. According to the pre-calibrated correspondence between the unbalance phase and the deduplication azimuth, the subsequent deduplication reference azimuth on the clockwise side and the subsequent deduplication reference azimuth on the counterclockwise side are determined according to the phases of the two expected residual unbalance vectors respectively. The portion of the corresponding expected residual unbalance exceeding the allowable residual unbalance is determined as the reserved correction amount on the clockwise side and the reserved correction amount on the counterclockwise side respectively. Based on the circumferential range occupied by the candidate first deduplication pit, the remaining allowable correction amount on the clockwise and counterclockwise sides of the candidate first deduplication pit is obtained respectively, and the candidate first deduplication scheme in which the remaining allowable correction amount on both sides is not less than the corresponding side reserved correction amount is retained. Calculate the difference between the remaining allowable correction amount on the clockwise side and the reserved correction amount on the clockwise side, and the difference between the remaining allowable correction amount on the counterclockwise side and the reserved correction amount on the counterclockwise side for each retained candidate initial deduplication scheme. Take the smaller of the two differences as the comparison value of the corresponding candidate initial deduplication scheme. Compare the comparison values ​​of each retained candidate initial deduplication scheme, and determine the candidate initial deduplication scheme with the largest comparison value as the target initial deduplication scheme; The first deduplication is completed according to the target first deduplication scheme. The remaining processable range on the clockwise and counterclockwise sides of the first deduplication pit is respectively used as the clockwise reserved correction area and the counterclockwise reserved correction area. After the initial weight reduction, the dynamic balance of the fan blades to be corrected is re-measured. According to the pre-calibrated correspondence between the unbalance phase and the weight reduction direction, the corresponding reserved correction area is selected based on the offset direction of the residual unbalance phase relative to the center phase of the initial weight reduction pit. The subsequent weight reduction position and subsequent weight reduction amount are determined within the selected reserved correction area.

2. The fan blade dynamic balancing correction method according to claim 1, characterized in that, If no candidate initial deduplication scheme is retained, the fan blade to be corrected is marked as exceeding the preset correction range, and the deduplication correction of the fan blade to be corrected is terminated. The initial center imbalance vector, clockwise boundary imbalance vector, and counterclockwise boundary imbalance vector are obtained as follows: The unbalance quantity and unbalance phase obtained from each initial dynamic balance test are converted into the corresponding initial unbalance vector. The average value of the components of each initial unbalance vector in two mutually perpendicular directions is calculated, and the initial center unbalance vector is obtained based on the average value of the two components. Using the phase of the initial center unbalance vector as a reference, calculate the phase offset of each initial unbalance vector along the clockwise and counterclockwise directions respectively; The initial unbalance vector with the largest phase offset in the clockwise direction is taken as the initial clockwise boundary vector, and the initial unbalance vector with the largest phase offset in the counterclockwise direction is taken as the initial counterclockwise boundary vector. The clockwise angle transmission error, counterclockwise angle transmission error, and circumferential positioning error of the de-weighting position are obtained respectively during the process of the fan blade to be corrected being transferred from the dynamic balance detection position to the de-weighting position. The phase of the initial clockwise boundary vector is extended according to the clockwise angle transmission error and the circumferential positioning error to obtain the clockwise boundary imbalance vector; the phase of the initial counterclockwise boundary vector is extended according to the counterclockwise angle transmission error and the circumferential positioning error to obtain the counterclockwise boundary imbalance vector.

3. The fan blade dynamic balancing correction method according to claim 1, characterized in that, The remaining allowable correction amount on the candidate first deduplication pit side is calculated as follows: Based on the candidate first deduplication position and the candidate first deduplication weight, the arc segment of the pit opening occupied by the fan blade to be corrected along the pit edge of the candidate first deduplication pit is obtained. Within the allowable deduplication range on the side corresponding to the pit opening arc segment, the minimum allowable distance that needs to be retained between the candidate first deduplication pit and the adjacent deduplication pit or the boundary of the allowable deduplication range is deducted to obtain the effective machinable arc length on that side. The number of deduplication pits that this side can accommodate is determined based on the effective machinable arc length, the arc length of the opening of a single deduplication pit, and the minimum allowable distance between adjacent deduplication pits. Based on the maximum allowable pit volume at the location of each subsequent de-duplication pit, the material density of the blade to be corrected, and the distance from the center of each subsequent de-duplication pit to the rotation axis of the blade to be corrected, the maximum allowable correction amount of each subsequent de-duplication pit is obtained. According to the pre-defined correspondence between the unbalanced phase and the de-duplication orientation, the correction direction corresponding to each subsequent de-duplication pit is determined, and the effective correction amount of each subsequent de-duplication pit on the corresponding subsequent de-duplication reference orientation is obtained based on the phase difference between the correction direction and the corresponding subsequent de-duplication reference orientation. The effective correction amounts of each subsequent deduplication pit that can be accommodated on this side are added together to obtain the remaining allowable correction amount on this side.

4. The fan blade dynamic balancing correction method according to claim 3, characterized in that, When there are existing deduplication pits within the allowed deduplication range, the candidate initial deduplication scheme is set as follows: Obtain the pit opening range of each existing deduplication pit, and extend the minimum allowable distance from the pit opening boundary of each existing deduplication pit along both sides in the circumferential direction to form the occupied arc segment corresponding to each existing deduplication pit. Subtract each occupied arc segment from the allowed deduplication range to obtain the processable arc segment available for initial deduplication; Based on the phase of the initial center unbalance vector, candidate first deduplication positions are arranged at preset circumferential intervals within the machinable arc segment, and multiple candidate first deduplication weights are set for each candidate first deduplication position. A candidate first deduplication scheme consists of a candidate first deduplication location and a candidate first deduplication weight. The arc segment of the pit corresponding to the candidate first deduplication scheme is located within the processable arc segment, and the circumferential distance between it and the existing deduplication pit is not less than the minimum allowable distance.

5. The fan blade dynamic balancing correction method according to claim 1, characterized in that, The initial correction vector and subsequent weight removal are obtained as follows: For the same type of fan blade, perform weight reduction calibration at different weight reduction radii, record the weight reduction amount and the change in dynamic balance before and after weight reduction, and obtain the weight reduction conversion value corresponding to each weight reduction radius. Based on the candidate initial deduplication weight, the deduplication radius corresponding to the candidate initial deduplication position, and the deduplication conversion value of the deduplication radius, the initial correction vector corresponding to the candidate initial deduplication scheme is obtained; After the initial deduplication is completed, the actual correction vector generated by the initial deduplication is obtained based on the initial center unbalance vector and the remeasured residual unbalance vector, and the deduplication conversion value corresponding to the initial deduplication position is corrected based on the actual correction vector and the actual initial deduplication weight. The subsequent weight removal weight is calculated based on the remeasured residual imbalance, the weight removal radius corresponding to the subsequent weight removal position, and the corrected weight removal conversion value. Based on the subsequent weight removal and the effective machinable arc length of the selected reserved correction area, determine the number of subsequent weight removal pits and the weight removal of each subsequent weight removal pit.

6. The fan blade dynamic balancing correction method according to claim 5, characterized in that, Before forming subsequent deduplication pits, the actual correction direction generated by the first deduplication is verified: Record the actual center phase of the first de-weighting pit. According to the correspondence between the unbalanced phase and the de-weighting orientation, convert the phase of the actual correction vector to the circumferential reference of the fan blade, and calculate the phase deviation between the converted phase and the actual center phase of the first de-weighting pit. Subsequent deduplication must simultaneously meet the following requirements: the phase deviation is within the preset phase deviation range, and the remaining allowable correction amount of the selected reserved correction area is not less than the subsequent deduplication weight; If the phase deviation exceeds the preset phase deviation range, the subsequent deduplication is stopped, and the circumferential reference feature position of the fan blade to be corrected is reacquired. The reacquired circumferential reference feature position is compared with the circumferential reference feature position recorded before the initial dynamic balancing test to obtain the circumferential reference offset angle. The circumferential reference offset angle is used to correct the residual unbalance phase of the retest, and the actual correction vector and the phase deviation are recalculated. If the corrected phase deviation still exceeds the preset phase deviation range, the deduplication of the fan blade to be corrected is terminated; if the remaining allowable correction amount in the selected reserved correction area is less than the subsequent deduplication amount, the fan blade to be corrected is recorded as exceeding the preset correction range.

7. A calibration device for implementing the dynamic balancing calibration method for fan blades according to any one of claims 1 to 6, characterized in that, include: The module includes: a fan blade feeding module (1), a fan blade picking and flipping module (2), a fan blade angle identification module (3), a dynamic balance initial measurement module (4), a milling weight removal module (5), a dynamic balance re-measurement module (6), and a qualified fan blade receiving module (7). The fan blade angle identification module (3), dynamic balance initial measurement module (4), milling deweight removal module (5) and dynamic balance re-measurement module (6) are set sequentially along the correction flow direction of the fan blade; The blade picking and flipping module (2) covers the blade feeding module (1), blade angle identification module (3), dynamic balance initial measurement module (4), milling weight removal module (5), dynamic balance re-measurement module (6) and qualified blade receiving module (7) for picking, flipping and transferring blades; The fan blade angle recognition module (3) is used to confirm the placement angle of the fan blade when it enters the dynamic balance preliminary measurement module (4); The dynamic balancing initial measurement module (4) is used to obtain the unbalance amount and unbalance phase before the fan blades are de-weighted; The milling de-weighting module (5) is used to form de-weighting pits at the corresponding positions of the fan blades according to the unbalance amount and unbalance phase. The dynamic balancing retest module (6) is used to obtain the residual unbalance amount and residual unbalance phase after the formation of the de-weighting pit; The qualified fan blade receiving module (7) is used to receive fan blades whose residual imbalance reaches the qualified condition.

8. The calibration device according to claim 7, characterized in that, The blade picking and flipping module (2) sequentially transfers the blades in the blade feeding module (1) to the blade angle identification module (3), dynamic balance initial measurement module (4), milling weight removal module (5) and dynamic balance re-measurement module (6). When the residual imbalance obtained by the dynamic balance retest module (6) does not meet the qualified condition, the fan blade pick-up and flip module (2) transfers the fan blade back to the milling de-weighting module (5), and the milling de-weighting module (5) forms a subsequent de-weighting pit on the fan blade. When the residual imbalance obtained by the dynamic balance retest module (6) reaches the qualified condition, the fan blade pick-up and flip module (2) transfers the fan blade to the qualified fan blade receiving module (7).

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