CN-121977470-A - Rebound measurement and evaluation method for corrugated foil radial overlap bearing

CN121977470ACN 121977470 ACN121977470 ACN 121977470ACN-121977470-A

Abstract

The invention discloses a rebound measurement and evaluation method of a corrugated foil radial overlap bearing, and belongs to the field of precision forming and bearing manufacturing. The method comprises the steps of firstly collecting a high-resolution image of a section of a single wave foil, extracting a contour point set, obtaining an overall base circle radius through least square fitting, converting the base circle center serving as a pole to a polar coordinate system, calculating radial fluctuation, dividing lobe intervals according to a design pitch angle, and carrying out local circle fitting on each lobe to obtain wave height, local arc radius and angle. And then the rebound errors of the whole, wave height and the radius of the partial circular arc are calculated by combining the design values. On the basis, the standard deviation of each lobe is counted and normalized to obtain a consistency index, and finally a weighted comprehensive evaluation function is constructed for quantitatively evaluating and comparing rebound control levels of different shaping and heat treatment processes. The invention realizes the integrated non-contact precise measurement and quantitative evaluation of the whole rebound and the local rebound, has high efficiency and good repeatability, and provides a reliable basis for process optimization.

Inventors

CHEN LIHAI
PANG XIAOXU
WANG XIAOQIANG
JIA DONG
LI YICAN
LI ZHENSHUI
Long Yiyang
ZHANG ZHIHUI
JIA CHENHUI
YANG FANG
ZHONG ZHIDAN

Assignees

河南科技大学

Dates

Publication Date: 20260505
Application Date: 20260113

Claims (10)

1. A rebound measurement method of a corrugated foil radial lap joint bearing is characterized in that the corrugated foil radial lap joint bearing is formed by circumferentially lap-jointing and assembling M identical corrugated foils into a complete circumference, the rebound measurement method is carried out on a single corrugated foil, and the design central angle corresponding to the single corrugated foil is Z; the rebound measurement method comprises the following steps: S1, obtaining design parameters of a single-chip corrugated foil, wherein the design parameters comprise a design base radius R D , a design wave height h D , a design local arc radius R 1D and a design pitch angle theta; S2, collecting a high-resolution image of a section of the single-chip corrugated foil formed by stamping, and then sequentially carrying out graying, filtering and edge detection on the high-resolution image to obtain a profile point set { P i =(X i ,Y i ) } of the single-chip corrugated foil; S3, fitting an integral base circle and dividing lobes, namely fitting a least square circle according to the profile point set to obtain an integral base circle center O (X o ,Y o ) obtained by fitting and an actually measured integral base circle radius R, establishing a polar coordinate system by taking the integral base circle center O obtained by fitting as a pole, converting the profile point set obtained in the step S2 into a polar coordinate form to obtain a radial fluctuation curve delta d (gamma), and dividing the radial fluctuation curve into N lobe sections according to a design pitch angle theta; S4, measuring and calculating local geometric parameters, namely respectively carrying out local circle fitting on contour points in each lobe section, and measuring and calculating the measured wave height h k , the measured local arc radius R 1k and the measured local arc angle beta k of each lobe; S5, calculating rebound errors, namely respectively calculating an overall base circle radius rebound error delta R , a wave height rebound error delta h and a local arc radius rebound error delta R1 based on the design reference value R D 、h D 、R 1D , the measured overall base circle radius R obtained by measurement, the measured wave height h k of each lobe and the measured local arc radius R 1k .
2. The measurement method according to claim 1, wherein in step S2, the high resolution image is acquired by an industrial camera with a pixel resolution of not less than 300 ten thousand pixels, the filtering process includes median filtering and gaussian filtering, the edge detection employs a Canny algorithm, and a connected region with the largest length is reserved as the contour point set by connected region analysis.
3. The measurement method according to claim 1, wherein in step S3, the design pitch angle θ = Z/N, where N is the number of lobes of the monolithic foil.
4. The method according to claim 1, wherein in step S4, the measured wave height h k is a difference between the maximum radial distance d i of the profile points in the corresponding lobe segment and the measured overall base circle radius R, and the measured partial arc angle β k is obtained by calculating a polar angle difference between the profile points at both ends of the corresponding lobe segment in a polar coordinate system.
5. The measurement method according to claim 1, wherein in step S4, when fitting a local circle to each lobe, the measured local arc radius R 1k is obtained by selecting a subset of contour points in the neighborhood angle range of the lobe with the identified peak point of the lobe as the center and performing least square circle fitting.
6. The measurement method according to claim 1, wherein in step S5, the overall base radius rebound error is: 。
7. the measurement method according to claim 1, wherein in step S5, the wave height resilience error is: ; Wherein, the The average value of the measured wave heights of all the lobes; , 。
8. The method according to claim 7, wherein in step S5, the local arc radius rebound error is: ; Wherein, the The average value of the radius of the partial arc is measured for all lobes, 。
9. The method of measurement according to claim 1, wherein the monolithic foil is made of Inconel-X750 material with a thickness of 0.1mm.
10. The rebound evaluation method of the corrugated foil radial lap bearing is characterized by comprising the following steps of: P1, acquiring measurement data, namely acquiring an overall base circle radius rebound error delta R , a wave height rebound error delta h , a local arc radius rebound error delta R1 , an actual measured wave height h k of each lobe and an actual measured local arc radius R 1k of the formed monolithic corrugated foil by adopting the measurement method as claimed in claim 1; And P2, calculating standard deviation, namely respectively calculating the wave height standard deviation sigma h and the local arc radius standard deviation sigma R1 of each lobe according to the following formula: ; ; and P3, calculating consistency indexes, namely respectively calculating a wave height consistency index C h and a local arc radius consistency index C R1 according to the following formula: ; P4, comprehensively evaluating, namely presetting a maximum deviation value delta Rmax 、δ hmax 、δ R1max 、C hmax 、C R1max allowed by each evaluation index; Normalizing the whole base circle radius rebound error delta R , the wave height rebound error delta h , the local arc radius rebound error delta R1 , the wave height consistency index C h and the local arc radius consistency index C R1 into ：f 1 =δ R /δ Rmax ,f 2 =δ h /δ hmax ,f 3 =δ R1 /δ R1max ,f 4 =C h /C hmax ,f 5 =C R1 /C R1max ; Then the evaluation function is synthesized F=w 1 ·f 1 +w 2 ·f 2 +w 3 ·f 3 +w 4 ·f 4 +w 5 ·f 5 ; Where w 1 ,w 2 ,w 3 ,w 4 ,w 5 is a weight coefficient, and w 1 +w 2 +w 3 +w 4 +w 5 =1.

Description

Rebound measurement and evaluation method for corrugated foil radial overlap bearing Technical Field The invention relates to the field of precision forming and bearing manufacturing, in particular to a rebound measuring and evaluating method of a corrugated foil radial lap joint bearing. Background Radial gas Foil bearings (Foil bearings) are widely used in tip equipment such as micro gas turbines, air circulators, high speed turbomachinery, and the like due to their outstanding advantage of not requiring external lubrication under high speed, high temperature environments. The core elastic element of the bearing, namely the corrugated foil, is usually manufactured by precision stamping, roll bending forming and heat treatment of high-temperature high-elasticity alloy thin strips (the thickness is about 0.05-0.15 mm) such as Inconel-X750 and the like. The corrugated foil has radial lap joint corrugated structures which are periodically distributed along the circumferential direction, and the geometric accuracy after forming, particularly the rebound caused by elastic recovery of materials, directly determines the assembly pretightening force of the corrugated foil and the top foil, the initial clearance of the bearing, the rigidity of an oil film and the dynamic stability, and is a key factor influencing the final performance of the bearing. At present, for the complex thin-wall elastic element with integral arc bending and a plurality of local convex peaks, the control and detection of the forming precision mainly face the following technical problems (1) the prior art relies on a single measuring mode. For example, a contact profiler (e.g., a three-coordinate measuring machine) is used to measure a profile along the cross-section of the corrugated foil, but the contact probe is prone to additional deformation of the flexible foil, resulting in measurement distortion and inefficiency. Or simply comparing by using an optical projector, but only obtaining the dimension of a single dimension (such as the whole radius or the height of each peak), and not separating and quantifying the whole base circle bending rebound and the local peak geometric rebound under the same measuring frame simultaneously and accurately. This results in a lack of comprehensive data support for process adjustments and (2) existing quality control mostly relies on trial and error experience and mold compensation, with repeated trial and error to bring product dimensions into tolerance. This approach lacks quantitative and comprehensive rebound evaluation indexes, and cannot scientifically correlate the process parameters such as "punching pressure", "die gap", "heat treatment system", etc. with the final "comprehensive rebound state". The process development period is long, the cost is high, and the process development period is difficult to meet the requirements of customized production with multiple specifications and small batches, and (3) for the corrugated foil with multiple identical lobes, the consistency of the geometric shapes (wave height and curvature) of each lobe is important for the uniform distribution of bearing load of a shaft. The existing method lacks effective quantitative evaluation of consistency among various lobes, and is difficult to identify and eliminate the difference among the lobes caused by uneven material flow or die abrasion. Therefore, a non-contact detection method aiming at a radial lap-joint wave foil structure and capable of realizing integral and local measurement and quantitative comprehensive evaluation is needed to accurately guide the optimization and stable production of a forming process. Disclosure of Invention The invention aims to overcome the defects of the prior art and provides a rebound measurement and evaluation method of a corrugated foil radial lap joint bearing. The method aims at realizing (1) obtaining the whole set of geometric parameters such as the whole base circle radius of the wave foil, the wave height of each lobe, the radius of the local circular arc, the angle and the like at one time through non-contact optical imaging and digital image processing. (2) The overall and local spring back errors are accurately calculated and the consistency between lobes is quantified. (3) And constructing a comprehensive rebound evaluation function, and providing objective and quantitative decision basis for comparing the merits of different process parameter combinations, thereby guiding process optimization efficiently. In order to achieve the above purpose, the invention adopts the following specific scheme: in a first aspect, the invention provides a rebound measurement method of a corrugated foil radial lap joint bearing, wherein M corrugated foils with the same thickness are circumferentially lap-jointed and assembled into a complete circumference, the rebound measurement method is carried out on a single corrugated foil, and the design central angle corresponding to the single