A coaxiality measurement method based on turntable angular swing error measurement compensation

Abstract

The application relates to a coaxiality measurement method based on a turntable angular swing error measurement compensation, and relates to a coaxiality measurement method. In order to solve the problem that the measurement reference axis is deviated due to air pressure, load and other reasons during measurement of a turntable, the measurement rotary shaft and the turntable geometric axis are deviated, rotary error is introduced, the measurement precision of an aero-engine rotor is reduced, and the coaxiality measurement precision of a part and an assembly is affected, the application comprises the following steps: step one, measuring the turntable rotary error when the workpiece height is h; step two, measuring the turntable rotary error when the workpiece height is 0; removing the equal-height block, repeating step one, and the measured turntable rotary error is recorded as r0. Step three, evaluating the turntable angular swing error; step four, evaluating the turntable rotary error when the workpiece height is H; step five, compensating the aero-engine rotor measurement rotary error; and step six, evaluating the aero-engine rotor coaxiality. The application belongs to the coaxiality measurement field.

Description

TECHNICAL FIELD

[0001] The application relates to a coaxiality measurement method and belongs to the coaxiality measurement field. BACKGROUND

[0002] Coaxiality is an important index of an aero-engine assembly, and some aero-engine main factories adopt a method of combining a precision mechanical turntable with a dial gauge to realize coaxial parameter measurement. Some units engaged in aero-engine maintenance also face the problem of low coaxiality measurement precision of aero-engine rotors, and currently, a method of combining a gas bearing turntable with a dial gauge is usually adopted to realize coaxiality measurement. However, due to reasons such as air pressure and load, the measurement reference axis will be offset during measurement, deviation of a measurement rotary shaft and a turntable geometric axis is caused, and rotary error is introduced, which reduces the measurement precision of the aero-engine rotor, affects the coaxiality measurement precision of parts and assemblies, and further causes excessive assembly error and huge economic loss caused by repeated disassembly and assembly. In order to improve the measurement precision of the aero-engine rotor, many scholars have proposed error compensation models and coaxiality measurement models. However, the existing research does not consider real-time monitoring and compensation of the rotary error of the turntable, and a coaxiality measurement method based on rotary error compensation is not proposed. Therefore, the coaxiality measurement method based on rotary error compensation has great significance for improving the coaxiality measurement precision. SUMMARY

[0003] The application is proposed to solve the problem that the measurement reference axis will be offset during measurement due to reasons such as air pressure and load of the turntable, deviation of a measurement rotary shaft and a turntable geometric axis is caused, rotary error is introduced, the measurement precision of the aero-engine rotor is reduced, and the coaxiality measurement precision of parts and assemblies is affected.

[0004] The technical scheme adopted by the application to solve the above problem is that the specific steps of the application are as follows.

[0005] Step one, measuring the rotary error of the turntable when the workpiece height is h;

[0006] Step two, measuring the rotary error of the turntable when the workpiece height is 0; removing the equal-height block, repeating step one, and recording the rotary error of the turntable as r0.

[0007] Step three, evaluating the angular swing error of the turntable;

[0008] Step four, evaluating the rotary error of the turntable when the workpiece height is H;

[0009] Step five, compensating the rotary error of the aero-engine rotor;

[0010] Step six, evaluating the coaxiality of the aero-engine rotor.

[0011] Further, the process of measuring the turntable runout error when the workpiece height is h in step one is as follows: the roundness standard and the equal-height block are placed on the turntable, and the positions are adjusted to be concentric, then the axial guide rail and the horizontal guide rail positions are adjusted, the ultra-precise displacement sensor is brought into contact with the roundness standard, the turntable is uniformly rotated at a working speed, γ represents the angle of rotation of the turntable, which is a real number between 0 and 360, and the measured turntable runout error at this time is recorded as r h .

[0012] Further, the angular swing of the turntable in step three can be expressed as:

[0013] θ γ = arctan(Δr / h) (1),

[0014] In formula (1), θ γ represents the angular swing error of the turntable, Δr = r h -r0.

[0015] Further, when the turntable is running at a certain speed, the height of the aero-engine rotor measurement section i is H, and the runout error caused by the angular swing error of the turntable at this time is:

[0016] Δr i = H x tanθ γ (2).

[0017] Further, the measurement equation of the rotor section to the center of rotation in step five is:

[0018]

[0019] In formula (3), e i represents the initial eccentricity of the measurement section i, α i represents the eccentric angle of the section i, ρ i represents the distance from the probe of the section i to the measurement center, r i represents the radius of the section i, Δr i represents the runout error of the section i due to the angular swing error, and γ i represents the data collection angle of the aero-engine rotor measurement section i.

[0020] According to the Fourier series expansion formula (3), then neglecting the high-order terms, the section profile measurement data containing the runout error can be obtained:

[0021] ρ i = e i cos(γ i -α i )+r i +Δr i (4),

[0022] Then, the aero-engine rotor cross-section profile data after rotary error real-time compensation can be expressed as:

[0023] r i = p i - e i cos (gamma i - alpha i ) - delta r i (5),

[0024] So far, the rotary reference rotary error synchronous monitoring and compensation of the rotary table can be realized.

[0025] Further, the compensated data horizontal and vertical coordinates in step six can be used to evaluate the aero-engine rotor coaxiality:

[0026]

[0027] In formula (6), x i represents the cross-section profile horizontal coordinate, and y i represents the cross-section profile vertical coordinate.

[0028] Then, the measurement cross-section center coordinates are:

[0029]

[0030] In formula (7), n represents the number of measurement points, a represents the cross-section center horizontal coordinate, and b represents the cross-section center vertical coordinate.

[0031] According to the two cross-section centers, the reference axis is determined, and the distance from the center of the kth measurement cross-section to the reference axis is e k Then, the rotary body coaxiality can be expressed as:

[0032] c = max {2 x e k} (8),

[0033] So far, the coaxiality measurement based on rotary error compensation of the rotary table measurement reference is realized.

[0034] The beneficial effects of the present application are that the present application considers the rotary error generated by the rotary table angular swing, and performs real-time monitoring and compensation, and proposes a coaxiality measurement method based on rotary error compensation, which is of great significance for aero-engine rotor coaxiality ultra-precision measurement and assembly measurement guidance. The present application solves the problem of the shift of the measurement reference axis caused by the rotary table due to air pressure, load and other reasons during measurement, reduces the rotary error introduced by the measurement rotary axis and the geometric axis line deviation of the rotary table, improves the engine rotor measurement precision, and reduces the huge economic loss caused by repeated disassembly and assembly. The coaxiality measurement method based on rotary error compensation of the present application has great significance for improving the coaxiality measurement precision. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 is the structural schematic diagram of the angular swing device of the aero-engine measuring turntable;

[0036] Figure 2 is the schematic diagram of the turntable rotation error evaluation;

[0037] Figure 3 is the measurement model schematic diagram of coupling eccentric error and rotation error;

[0038] Figure 4 is the coaxiality measurement model schematic diagram. DETAILED DESCRIPTION

[0039] Specific implementation one: combined Figures 1 to 4 To illustrate the embodiment, the coaxiality measurement method based on the turntable angular swing error measurement compensation used in the angular swing device of the aero-engine measuring turntable includes an axial guide rail 1, a horizontal guide rail 2, an ultra-precision displacement sensor 3, a roundness standard 4, an isohypse block 5, a turntable 6, and a round grating 7. The axial guide rail 1 and the turntable 6 are arranged side by side, the horizontal guide rail 2 is installed on the axial guide rail 1, and the horizontal guide rail 2 can reciprocate up and down along the axial guide rail 1, the round grating 7 is installed on the rotating shaft of the turntable 6, the isohypse block 5 is arranged on the turntable 6, the roundness standard 4 is installed on the isohypse block 6, and the ultra-precision displacement sensor 3 is installed on one end of the horizontal guide rail 2 close to the turntable 6. The specific steps of the coaxiality measurement method based on the turntable angular swing error measurement compensation are as follows:

[0040] Step one, measuring the turntable rotation error when the workpiece height is h;

[0041] Step two, measuring the turntable rotation error when the workpiece height is 0; remove the isohypse block 5 and repeat step one, and the measured turntable rotation error is recorded as r0.

[0042] Step three, evaluating the angular swing error of the turntable 6;

[0043] Step four, evaluating the turntable rotation error when the workpiece height is H;

[0044] Step five, measuring the rotation error compensation of the aero-engine rotor;

[0045] Step six, evaluating the coaxiality of the aero-engine rotor.

[0046] Specific implementation two: combined Figures 1 to 4In the embodiment, the process of measuring the rotation error of the turntable when the height of the workpiece is h in step one of the coaxiality measurement method based on the turntable angular swing error measurement compensation is as follows: the roundness standard (4) and the equal-height block (5) are placed on the turntable (6), and the positions are adjusted to be concentric, then the positions of the axial guide rail (1) and the horizontal guide rail (2) are adjusted, the ultra-precision displacement sensor (3) is brought into contact with the roundness standard (4), the turntable is uniformly rotated at a working speed, γ represents the angle through which the turntable is rotated, and is a real number between 0 and 360, and the rotation error of the turntable at this time is recorded as r h .

[0047] Specific embodiment three: combined with Figures 1 to 4 In the embodiment, the angular swing of the turntable (6) in step three of the coaxiality measurement method based on the turntable angular swing error measurement compensation can be expressed as:

[0048] θ γ = arctan (Δr / h) (1),

[0049] In formula (1), θ γ represents the angular swing error of the turntable, Δr = r h -r0.

[0050] Specific embodiment four: combined with Figures 1 to 4 In the embodiment, when the turntable is operated at a certain speed, the height of the measurement section i of the aero-engine rotor is H, and the rotation error caused by the angular swing error of the turntable at this time is:

[0051] Δr i = H x tan θ γ (2).

[0052] Specific embodiment five: combined with Figures 1 to 4 In the embodiment, the measurement equation of the distance from the rotor section to the rotation center in step five of the coaxiality measurement method based on the turntable angular swing error measurement compensation is:

[0053]

[0054] In formula (3), e i represents the initial eccentricity of the measurement section i, α i represents the eccentric angle of the center of the section i, ρ i represents the distance from the probe of the section i to the measurement center, r i represents the radius of the section i, Δr i represents the rotation error of the section i caused by the angular swing error, and γ iData acquisition angle of aero-engine rotor measurement section i;

[0055] According to Fourier series expansion formula (3), and then omit the high order term, the section profile measurement data containing the rotation error can be obtained:

[0056] ρ i = e i cos(γ i - α i ) + r i + Δr i (4),

[0057] Then, after real-time compensation of the rotation error, the aero-engine rotor section profile data can be expressed as:

[0058] r i = ρ i - e i cos(γ i - α i ) - Δr i (5),

[0059] At this point, synchronous monitoring and compensation of the rotation error of the rotation table rotation reference can be realized.

[0060] Specific implementation method six: combined with Figures 1 to 4 To illustrate this embodiment, the horizontal and vertical coordinates of the compensated data in step six of the method for measuring the coaxiality of the aero-engine rotor based on the rotation table angular swing error measurement and compensation can be used to evaluate the coaxiality of the aero-engine rotor:

[0061]

[0062] In formula (6), x i represents the horizontal coordinate of the section profile, and y i represents the vertical coordinate of the section profile.

[0063] Then, the measurement section center coordinates are:

[0064]

[0065] In formula (7), n represents the number of measurement points, a represents the horizontal coordinate of the section center, and b represents the vertical coordinate of the section center.

[0066] According to the two section centers, the reference axis thereof is determined, and the distance from the center of the kth measurement section to the reference axis thereof is e k , and the coaxiality of the rotation body can be expressed as:

[0067] c = max {2 × e k} (8),

[0068] Thus, the coaxiality measurement based on the turntable measurement reference rotation error compensation is realized.

[0069] The above is only the preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above with the preferred embodiment, it is not intended to limit the present application. Any skilled person in the art can make some changes or modifications to the above disclosed technical content without departing from the technical solution of the present application, and the equivalent embodiments with equivalent changes are equivalent. Any simple modification, equivalent replacement and improvement of the above embodiments within the technical solution of the present application, the technical essence of the present application, and the spirit and principles of the present application are still within the protection scope of the technical solution of the present application.

Claims

1. A coaxiality measurement method based on turntable angular swing error measurement compensation, wherein the angular swing device of the turntable for aircraft engine measurement used in the method comprises an axial guide rail (1), a horizontal guide rail (2), an ultra-precision displacement sensor (3), a roundness standard (4), a contour block (5), a turntable (6) and a circular grating (7); the axial guide rail (1) and the turntable (6) are arranged side by side, the horizontal guide rail (2) is installed on the axial guide rail (1), and the horizontal guide rail (2) can move up and down along the axial guide rail (1), the circular grating (7) is installed on the rotating shaft of the turntable (6), the contour block (5) is arranged on the turntable (6), the roundness standard (4) is installed on the contour block (6), and the ultra-precision displacement sensor (3) is installed on one end of the horizontal guide rail (2) close to the turntable (6); the method is characterized in that: The specific steps of the coaxiality measurement method based on turntable angular swing error measurement and compensation are as follows: Step 1: Measure the height of the workpiece h Turntable rotation error; Step 2: Measure the turntable rotation error when the workpiece height is 0; remove the equal height block (5) and repeat step 1. The turntable rotation error measured at this time is recorded as r 0; Step 3: Evaluate the angular swing error of the turntable (6); Step 4: Assess the workpiece height H Turntable rotation error; Step 5: Compensation for rotation error of aircraft engine rotor measurement; Step 6: Aero-engine rotor coaxiality assessment; The horizontal and vertical coordinates of the compensated data can be used to evaluate the coaxiality of the aircraft engine rotor: （6）， In formula (6), x i represents the horizontal coordinate of the cross-sectional morphology, y i represents the vertical coordinate of the cross-sectional morphology; The coordinates of the center of the measured section are: （7）， In formula (7), n Indicates the number of measurement points, a represents the horizontal coordinate of the center of the cross section, b Indicates the vertical coordinate of the center of the cross section; Determine the reference axis based on the two cross-section centers. k The distance from the center of the measuring section to its reference axis is e k , then the coaxiality of the rotating body can be expressed as: （8）， At this point, the coaxiality measurement based on the rotation error compensation of the turntable measurement reference is realized.

2. The coaxiality measurement method based on turntable angular pendulum error measurement and compensation according to claim 1 is characterized in that: The workpiece height measured in step 1 is h The process of measuring the turntable rotation error is as follows: put the roundness standard (4) and the equal height block (5) on the turntable (6), and adjust the position to the center, then adjust the position of the axial guide rail (1) and the horizontal guide rail (2), drive the ultra-precision displacement sensor (3) to contact the roundness standard (4), and make the turntable rotate one circle at a uniform speed at the working speed. γ Indicates the angle of the turntable rotation, which is a real number between 0 and 360. The turntable rotation error measured at this time is recorded as r h .

3. The coaxiality measurement method based on turntable angular pendulum error measurement and compensation according to claim 1 is characterized in that: The angular swing of the turntable (6) in step 3 can be expressed as: θ γ = arctan(∆ r / h )(1), In formula (1), θ γ Indicates the turntable angular error, ∆ r=r h - r 0.

4. The coaxiality measurement method based on turntable angular pendulum error measurement and compensation according to claim 1 is characterized in that: In step 4, when the turntable is running at a certain speed, the aircraft engine rotor measurement cross section i Height is H At this time, the rotation error caused by the turntable angular swing error is: ∆ r i = H ×tan θ γ (2)。 5. The coaxiality measurement method based on turntable angular pendulum error measurement and compensation according to claim 1 is characterized in that: The distance measurement equation from the rotor section to the center of rotation in step 5 is: （3）， In formula (3), e i Indicates the measurement section i The initial eccentricity, α i Represents cross section i The eccentric angle of the center of the circle, ρ i Represents cross section i The distance from the probe to the measurement center, r i Represents cross section i The radius, Δr i Represents cross section i The rotation error caused by the angular swing error is γ i Indicates the measurement cross section of an aircraft engine rotor i Data collection angle; According to the Fourier series expansion formula (3), and then ignoring the higher-order terms, the cross-sectional profile measurement data including the rotation error can be obtained: （4）， After real-time compensation of the rotation error, the cross-sectional profile data of the aircraft engine rotor can be expressed as: （5）， At this point, the synchronous monitoring and compensation of the turntable rotation reference rotation error can be achieved.

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