TYPICAL ROTATIONAL PART CHARACTERIZATION METHOD BASED ON ACTUALLY MEASURED RUN-OUT DATA

Abstract

The present invention provides a typical rotational part characterization method based on actually measured run-out data. Aiming at the characterization of rotational parts containing morphology data, the present invention proposes a matrix form characterization method in which microscopic run-out data and macroscopic axial size are comprehensively considered. In addition, the method can be applied to an assembly accuracy calculation process, and can characterize a single part containing morphology feature quantities by using only one matrix M. The calculation process of accuracy transfer is simplified, and a high-efficiency calculation model is provided for the prediction of assembly accuracy.

Claims

1. A typical rotational part characterization method based on actually measured run-out data, comprising the following steps: 1) measuring a mating face of a rotational part by a cylindricity measuring instrument to obtain run-out data D.sub.bot of a bottom end face, radial run-out data dR.sub.bot of a bottom spigot, run-out data D.sub.top of a top end face, and radial run-out data dR.sub.top of a top spigot; 2) processing the original run-out data obtained in step 1): since the data measured by the cylindricity measuring instrument is a vector matrix with n row(s) and 1 column, i.e., the data of each end face is an axial one-dimensional run-out value, the data at each spigot is a radial one-dimensional run-out value; and a corresponding method is used to process and obtain three-dimensional coordinate data of the mating face according to actually measured radius values r.sub.bot and r.sub.top at the circular end faces and measured radius values R.sub.bot and R.sub.top at the spigots in combination with actually measured run-out data; the processing method is as follows: for the data of the bottom end face, letting $\theta ={\left[\frac{2\pi }{n},\frac{4\pi }{n},\frac{6\pi }{n},\mathrm{.Math.},2\pi \right]}^T,$ then the X and Y coordinates at a bottom end face measuring point are:
X.sub.Dbot(i)=r.sub.bot×cos θ.sub.(i)i=1,2 . . . n−1,n
Y.sub.Dbot(i)=r.sub.bot×sin θ.sub.(i)i=1,2 . . . n−1,n integrating the X and Y coordinates X.sub.Dbot and Y.sub.Dbot at the bottom end face measuring point and the run-out data D.sub.bot of the bottom end face to obtain a processed bottom end face spatial coordinate matrix D.sub.bot′, and a top end face spatial coordinate matrix D.sub.top′ can be obtained in the same way; for the radial run-out data of the bottom spigot, according to the radial run-out data dR.sub.bot and the measured radius value R.sub.bot, the X and Y coordinates at a bottom spigot measuring point are:
X.sub.Rbot(i)=(R.sub.bot+dR.sub.Rbot(i))×cos θ.sub.(i)
Y.sub.Rbot(i)=(R.sub.bot+dR.sub.Rbot(i))×cos θ.sub.(i) due to the spigot plays a centering role in assembly, the main concern is about the position of a circle center, so letting Z.sub.Rbot=0.sub.n×1; integrating the X, and Z coordinates X.sub.Rbot, Y.sub.Rbot, and Z.sub.Rbot the bottom spigot run-out measuring point to obtain the processed bottom spigot face spatial coordinate matrix dR.sub.bot′, and the top spigot face spatial coordinate matrix dR.sub.top′ can be obtained in the same way; 3) performing least square fitting on the data obtained in step 2), and extracting the corresponding feature quantities; the extracting method is as follows: fitting the processed end face data D′.sub.bot and D′.sub.top by a least square plane, and the equation of the fitted plane is:
Ax+By+Cz+D=0 this plane can be regarded as an ideal plane rotated by a certain angle around X axis and Y axis respectively, and the corresponding deflection angles are respectively: $d{\theta }_x=-\frac{B}{C};d{\theta }_y=\frac{A}{C}$ for a typical rotational part, four deflection feature quantities can be extracted from the processed end face data, which are respectively: dθ.sub.x bot, dθ.sub.y_bot, dθ.sub.x_top and dθ.sub.y_top; fitting the processed spigot face data dR′.sub.bot and dR′.sub.top a least square circle, and the equation of the fitted circle is:
R.sup.2=(x−dX).sup.2+(y−dY).sup.2 for a typical rotational part, four eccentricity feature quantities can be extracted from the processed spigot face data, which are respectively: dX.sub.bot, dY.sub.bot, dX.sub.top and dY.sub.top; therefore, for any rotational part with spigots, the deflection feature quantities dθ.sub.x bot, dθ.sub.x_bot, dθ.sub.x_top and dθ.sub.y_top of the top and bottom end faces and the eccentricity feature quantities dX.sub.botd, dY.sub.bot, dX.sub.top and dY.sub.top of the top and bottom spigots of the rotational part can be obtained by performing corresponding data processing on the actually measured run-out data of the mating faces; 4) expressing the feature quantities of the part extracted in step 3) in a matrix form: since most spigots adopt a connection form of short spigot connection, and the spigot measuring point is very close to an adjacent end face, compared with the axial height Z of the part, the axial distance between the spigot measuring point and the adjacent end face can be ignored; therefore, the end surface morphology feature quantity and the spigot morphology feature quantity are coupled into a spatial circular plane; any rotational part with spigots will include a bottom spatial circular plane and a top spatial circular plane, and the corresponding bottom circular plane and top circular plane are respectively expressed as: $P_{bot}=\left[\begin{array}{cccc}1& 0& d{\theta }_{y\_\mathrm{bot}}& d{X}_{bot}\\ 0& 1& -d{\theta }_{x\_\mathrm{bot}}& d{Y}_{bot}\\ -d{\theta }_{y\_\mathrm{bot}}& d{\theta }_{x\_\mathrm{bot}}& 1& 0\\ 0& 0& 0& 1\end{array}\right]$ $P_{top}=\left[\begin{array}{cccc}1& 0& d{\theta }_{y\_\mathrm{top}}& d{X}_{\mathrm{top}}\\ 0& 1& -d{\theta }_{x\_\mathrm{top}}& d{Y}_{\mathrm{top}}\\ -d{\theta }_{y\_\mathrm{top}}& d{\theta }_{x\_\mathrm{top}}& 1& Z\\ 0& 0& 0& 1\end{array}\right]$ 5) performing spatial eccentricity and deflection adjustment on the bottom circular plane of the part obtained in step 4): first adjusting the circle center of the bottom circular plane to the origin of absolute coordinates, and then adjusting the spatial deflection amount of the bottom circular plane to 0; i.e., the bottom plane is transformed from a spatial circular plane with a certain eccentricity amount and deflection amount into an ideal circular plane of which the circle center is located at the origin of absolute coordinates; the ideal circular plane can be expressed by a fourth-order unit matrix E, and the whole transformation process is: $i.e.:\begin{array}{c}{P}_{\mathrm{bot}}\stackrel{T}{.Math.}E\\ T\times P_{\mathrm{bot}}=E\end{array}$ then the top circular plane undergoes the same transformation, and the transformation process is: $i.e.:\begin{array}{c}{P}_{\mathrm{top}}\stackrel{T}{.Math.}{P}_{\mathrm{top}}^{\prime }\\ T\times P_{\mathrm{top}}=P_{\mathrm{top}}^{\prime }\end{array}$ at this moment, the bottom circular plane has been transformed into an ideal circular plane, which no longer contains morphology feature quantities, and the morphology of the bottom circular plane is coupled to the top circular plane; letting M=F.sub.top′, using a matrix M to characterize a rotational part that contains microscopic morphology features and macroscopic axial height, and using the matrix in sub sequent assembly accuracy calculation process.

Description

DESCRIPTION OF DRAWINGS

[0027] FIG. 1 is a schematic diagram of a spatial circular plane of a typical rotational part.

[0028] FIG. 2 shows a transformation process of a bottom circular plane of a part.

[0029] FIG. 3a shows actual measured run-out data of end faces of an aeroengine compressor rotor part.

[0030] FIG. 3b shows actual measured radial run-out data of spigots of an aeroengine compressor rotor part.

[0031] FIG. 4a is a least square fitting plane.

[0032] FIG. 4b is a least square fitting circle.

DETAILED DESCRIPTION

[0033] To make the purpose, the technical solution and the advantages of the present invention more clear, the technical solution in the present invention will be fully described below by taking a typical rotational part (a certain type of engine rotor part) as an example in combination with the drawings of the present invention.

[0034] An existing iMap4 integrated measurement and assembly platform from a company is used to measure the rotor, wherein a set of inner ring run-out data and a set of outer ring run-out data are measured for each end face, and only one set of radial run-out data is measured for each spigot. The measured data is shown in FIG. 3.

[0035] The measuring point positions in a test process are: r.sub.bot1=123, r.sub.bot2=133, r.sub.top1=168, r.sub.top2=178, R.sub.bot=120 and R.sub.top=165. The axial height of the part is Z=120. The spatial point cloud data D.sub.bot_n×3 and D.sub.top_n×3 at the end faces and the spatial point cloud data dR.sub.bot_n×3 and dR.sub.top_n×3 at the spigots can be obtained by using the method in step 2 to process the actually measured data.

[0036] Least square plane fitting is performed on the processed spatial point cloud data at the end faces, and least square circle fitting is performed on the processed spatial point cloud data at the spigots. The fitting effect is shown in FIG. 4.

[0037] The corresponding morphology feature quantities of the mating faces can be extracted by fitting, as shown in Table 1:

TABLE-US-00001 Morphology feature quantities Value dθ.sub.x.sub.—.sub.bot (10.sup.−5 rad) 0.5129 dθ.sub.y.sub.—.sub.bot (10.sup.−5 rad) 2.0986 dθ.sub.x.sub.—.sub.top (10.sup.−5 rad) −1.0230 dθ.sub.y.sub.—.sub.top (10.sup.−5 rad) 1.5391 dX.sub.bot (10.sup.−6 m) −4.1 dY.sub.bot (10.sup.−6 m) −2.7 dX.sub.top (10.sup.−6 m) −2.2 dY.sub.top (10.sup.−6 m) 3.5

[0038] The morphology feature quantities in Table 1 and the axial height Z of the part are respectively substituted into the matrices P.sub.bot and P.sub.top to obtain the bottom circular plane matrix and the top circular plane matrix of the part.

[0039] Eccentricity and deflection adjustment is performed on the bottom circular plane by the method of matrix transformation, and a transformation matrix T=P.sub.not.sup.−1 of the bottom circular plane can be obtained by the method described in step 5. Multiplying the top circular plane matrix P.sub.top by the matrix T, the transformed top circular plane matrix P.sub.top′ can be obtained.

[00006]$P_{\mathrm{top}}^{\prime }=\left[\begin{array}{cccc}1& 0& -0.5595E^{-5}& 0.6E^{-6}\\ 0& 1& 1.5359E^{-5}& 6.8E^{-6}\\ 0.5595E^{-5}& -1.5359E^{-5}& 1& 120\\ 0& 0& 0& 1\end{array}\right]$

[0040] Letting M=P.sub.top′, the matrix M is used to characterize the engine rotor part with the morphology features of the mating faces and the macroscopic axial size taken into consideration.