CN112364448A - Method for realizing linear assembly of aero-engine rotor - Google Patents

Abstract

The invention provides a method for realizing linear assembly of an aircraft engine rotor, and belongs to the technical field of precision assembly. The invention provides a feasible method aiming at optimizing rotor assembly phase as a target aiming at the 'bending' phenomenon after rotor assembly, which takes the actual rotation axis of a multi-stage rotor as a reference and adjusts the assembly phase of each stage of rotor step by step so as to ensure that the center of each stage of rotor is on the actual rotation axis as much as possible, thereby fundamentally lightening the 'bending' phenomenon after rotor assembly and improving the rotor assembly quality and the one-time assembly success rate.

Description

Method for realizing linear assembly of aero-engine rotor

Technical Field

The invention relates to a method for realizing linear assembly of an aircraft engine rotor, and belongs to the technical field of precision assembly.

Background

The core technology of the aircraft engine, as the bright bead on the industrial crown, is a typical high-precision technology product, is monopolized by a few developed countries for a long time, and strict technical blockade is implemented in China, so that a large amount of engineering experience and long-term technical accumulation far lead China. The rotor is taken as a core component of an aircraft engine, the assembly technology of the rotor is always the key point of the research field of the aircraft engine, although a large number of published documents simulating the rotor assembly technology can be found, due to the reasons of core technology blocking protection, military confidentiality, commercial confidentiality and the like, an engineering case and related result data aiming at the assembly technology of a real rotor system of the aircraft engine are almost blank, and the technical barrier is difficult to break.

The rotors are generally manufactured in a grading way and assembled in a stacking way, because the current domestic rotor assembly also depends on experience and trial and error methods in a large quantity, the offset of the centers of all levels of rotors relative to the actual rotation axis is often overlarge, and then a bent rotor is generated, and the bent rotor is easy to generate faults of vibration, friction and the like in a high-speed rotation state, so that the performance of an aeroengine is seriously influenced. Therefore, the assembly quality of the rotor is not high at present and only meets the requirement basically. With the increasing overall performance of the aircraft engine, the requirement on the core component rotor is also increased at a very high speed, and the assembly precision of the rotor is difficult to improve by purely depending on manual experience and trial and error.

Aiming at the problem of the bent rotor, the invention provides a linear assembly method based on the actual rotary axis, which seeks the optimal assembly phase between each stage of rotor through an assembly joint surface rotation matrix, further minimizes the distance from the center of each stage of rotor to the actual rotary axis, realizes the real linear assembly and improves the one-time assembly success rate of the rotor.

Disclosure of Invention

The method for realizing linear assembly of the rotor of the aircraft engine is characterized in that an actual rotation axis which passes through the center of the bottom surface of a bottom-stage rotor and is perpendicular to the bottom surface is used as a measurement standard of coaxiality during assembly, coordinate changes of the centers of all stages of rotors are expressed by means of a transformation matrix of assembly characteristics of two adjacent stages of rotors, the centers of all stages of rotors are enabled to be on the actual rotation axis as much as possible by the condition of minimizing the coaxiality, linear assembly of the rotors is really realized, and the success rate of primary assembly of the rotors is improved.

The technical scheme of the invention is as follows:

a method for realizing linear assembly of an aircraft engine rotor comprises the following steps:

step (1), a precision rotary table system is used as a basis, a monomer transformation matrix of each stage of rotor assembly characteristics is established through test data, the assembly process of two adjacent stages of rotors is represented by a rotation matrix of assembly joint surface characteristics, and a comprehensive transformation matrix from a bottom stage rotor to a top stage rotor is established by a rotor stacking theory;

four groups of data, namely the end face runout and the radial runout of the upper assembling face and the lower assembling face are measured according to the assembling characteristics of the single-stage rotor, and a transformation matrix from the lower assembling face to the upper assembling face of the single-stage rotor is established by using the groups of data as follows:

due to the existence of the processing error of the rotor, improper adjustment in the assembly test process and other factors, the joint end face of the spigot can incline when the two-stage rotor is assembled, the good centering and restraining effect of the spigot is considered, the assembly optimization of the two-stage rotor can be realized only by rotating the rotor around the z axis, and the assembly joint face rotating matrix T is introduced_1-1’As follows:

thus, the transformation matrix T of the assembly characteristics 0-2 at the time of assembly of the two-stage rotor_0-2Write as:

T_0-2＝T_0-1*T_1-1’*T_1‘-2

similarly, when the n-level rotor is assembled, the comprehensive transformation matrix is as follows:

T_0-n＝T_0-1*T_1-1’*T_1‘-2*……*T_m-m’*T_m’-n

wherein m is n-1;

T_0-nthe structure of (A) is as follows:

wherein R is_xyzRepresenting rotation of the bottom-stage rotor to the top-stage rotor about x, y, z, p_xyz＝[d_xn d_yn z_n]^TRepresenting the translation of the bottom-stage rotor to the top-stage rotor in the x, y, z directions;

step (2), an optimization method for seeking an optimal assembly phase by minimizing coaxiality is provided; the translation vector p in the comprehensive transformation matrix during the assembly of the n-level rotor_xyzCenter O characterizing Assembly feature 0₀How to change to the center O of the assembly feature n_nWherein the sum of the x and y components represents O_nDistance to the actual axis of revolution; the coaxiality is defined as: 2 [ (d)_xn)2+(d_yn)2]^1/2A function f (θ) as follows_zi) From the above analysis, f (θ) is known as an optimization target_zi) About theta_ziIn min { f (θ) }_zi) Solving to obtain the optimal phase when assembling the multistage rotor as an optimization target;

f(θ_zi)＝[(d_xn)²+(d_yn)²]；n＝2,3,4……；i＝1,2,3……n-1；

take two-stage rotor assembly as an example, i.e. when n is 2 and i is 1, θ_z1The direction of the adjustment phase of the lower-level rotor relative to the upper-level rotor is determined by the right-hand rule, and if the upper-level rotor needs to be adjusted during assembly, the rotating direction is the reverse direction; on the basis, 3 and 4 stages are optimized to n stages.

Step (3), rotor assembly visualization and comparison effect

And drawing an equivalent schematic diagram of the assembled rotor to check the actual pose of the rotor and compare the actual pose with the assembling effect during random assembly.

The invention has the beneficial effects that: the invention provides a feasible method aiming at optimizing rotor assembly phase as a target aiming at the 'bending' phenomenon after rotor assembly, which takes the actual rotation axis of a multi-stage rotor as a reference and adjusts the assembly phase of each stage of rotor step by step so as to ensure that the center of each stage of rotor is on the actual rotation axis as much as possible, thereby fundamentally lightening the 'bending' phenomenon after rotor assembly and improving the rotor assembly quality and the one-time assembly success rate.

Drawings

FIG. 1 is a flow chart of the present invention.

Fig. 2 is a single stage rotor transformation matrix definition.

Fig. 3a is a schematic diagram of random assembly of a two-stage rotor.

Fig. 3b is a schematic diagram of the optimized assembly of the two-stage rotor.

Fig. 4 shows the coaxiality contrast in the two assembly modes.

Detailed Description

The invention is further described below with reference to the accompanying drawings, taking a 3-stage rotor assembly as an example.

Step one, single-stage rotor transformation matrix definition

And fitting the radial run-out and end run-out data based on a least square method By considering the eccentric error of rotor installation to obtain a fitting circle center (dx, dy) and a fitting plane Ax + By + Cz + D which is 0. (dx, dy) is an eccentric coordinate, d θ_x-B/C is the angle of rotation of the fitting plane about the x-axis relative to the reference plane, d θ_yAnd A/C is the rotation angle of the fitting plane relative to the reference plane around the y axis, and the rotation direction follows the right-hand spiral rule. Wherein, O_EIs the origin of a reference coordinate system, O₀Is the center of the lower bottom surface of the rotor, O₁The center of the upper bottom surface of the rotor, E represents a reference surface, 0 represents a lower bottom surface, and 1 represents an upper bottom surface, as shown in FIG. 2. The transformation matrix from E to 0 is T_E-0Transformation matrix from E to 1 as T_E-1So that the transformation matrix T is from 0 to 1_0-1＝T^-1 _E-0*T_E-1. The same method obtains the monomer transformation matrix of 2 and 3-stage rotors, as shown in table 1.

TABLE 1

Step two, establishing a stacking model

An optimized schematic diagram of a 2-stage rotor assembly is established considering the inclination of the joint surface of the two-stage rotor assembly, as shown in fig. 3. And simultaneously establishing a comprehensive change matrix during the assembly of the 2-stage and 3-stage rotors, thus obtaining the translation change of the center of the bottom-stage rotor to the centers of the 2 nd-stage and 3 rd-stage rotors about the x and y directions, namely f (theta)_zi). Using matlab to solve f (theta)_z1),f(θ_z2) Minimum assembly phase θ_z1＝230°,θ_z2＝215°。

And step three, establishing coaxiality contrast of optimized assembly and random assembly of the three-stage rotor.

Substituting the assembly phase solved in the second step into a comprehensive transformation matrix to obtain the coaxiality of the 2-level and 3-level rotor during optimization assembly; substituting a group of random assembly phases into the comprehensive transformation matrix to obtain the coaxiality of 2 and 3-level rotors during random assembly; line graphs were plotted for comparison, as in FIG. 4. Analysis shows that the coaxiality of the 2-level rotor and the 3-level rotor after optimized assembly is obviously reduced compared with random assembly, namely the rotors well realize 'linear assembly', and the assembly precision and quality are improved.

Claims (1)

1. A method for realizing linear assembly of an aircraft engine rotor is characterized by comprising the following steps:

step (1), a precision rotary table system is used as a basis, a monomer transformation matrix of each stage of rotor assembly characteristics is established through test data, the assembly process of two adjacent stages of rotors is represented by a rotation matrix of assembly joint surface characteristics, and a comprehensive transformation matrix from a bottom stage rotor to a top stage rotor is established by a rotor stacking theory;

four groups of data, namely the end face runout and the radial runout of the upper assembling face and the lower assembling face are measured according to the assembling characteristics of the single-stage rotor, and a transformation matrix from the lower assembling face to the upper assembling face of the single-stage rotor is established by using the groups of data as follows:

when the two-stage rotor is assembled, the joint end face of the spigot is inclined, the good centering and restraining effects of the spigot are considered, the assembly optimization of the two-stage rotor can be realized only by rotating the rotor around the z axis, and therefore the rotating matrix T of the joint surface is introduced_1-1’As follows:

thus, the transformation matrix T of the assembly characteristics 0-2 at the time of assembly of the two-stage rotor_0-2Write as:

T_0-2＝T_0-1*T_1-1’*T_1‘-2

similarly, when the n-level rotor is assembled, the comprehensive transformation matrix is as follows:

T_0-n＝T_0-1*T_1-1’*T_1‘-2*……*T_m-m’*T_m’-n

wherein m is n-1;

T_0-nthe structure of (A) is as follows:

wherein R is_xyzRepresenting rotation of the bottom-stage rotor to the top-stage rotor about x, y, z, p_xyz＝[d_xn d_yn z_n]^TRepresenting the translation of the bottom-stage rotor to the top-stage rotor in the x, y, z directions;

step (2), an optimization method for seeking an optimal assembly phase by minimizing coaxiality is provided; the translation vector p in the comprehensive transformation matrix during the assembly of the n-level rotor_xyzCenter O characterizing Assembly feature 0₀How to change to the center O of the assembly feature n_nWherein the sum of the x and y components represents O_nDistance to the actual axis of revolution; the coaxiality is defined as: 2 [ (d)_xn)2+(d_yn)2]^1/2A function f (θ) as follows_zi) From the above analysis, f (θ) is known as an optimization target_zi) About theta_ziIn min { f (θ) }_zi) Solving to obtain the optimal phase when assembling the multistage rotor as an optimization target;

f(θ_zi)＝[(d_xn)²+(d_yn)²]；n＝2,3,4……；i＝1,2,3……n-1；

take two-stage rotor assembly as an example, i.e. when n is 2 and i is 1, θ_z1The direction of the adjustment phase of the lower-level rotor relative to the upper-level rotor is determined by the right-hand rule, and if the upper-level rotor needs to be adjusted during assembly, the rotating direction is the reverse direction; on the basis, optimizing 3 and 4 to n levels;

step (3), rotor assembly visualization and comparison effect

And drawing an equivalent schematic diagram of the assembled rotor to check the actual pose of the rotor and compare the actual pose with the assembling effect during random assembly.

Images