A Tolerance Allocation Method for Large Rotary Equipment of Aero-Engines Based on Five-Parameter and Morphological Filtering

Abstract

The present invention is a tolerance allocation method for large-scale rotating equipment of aircraft engines based on five parameters and morphological filtering. The present invention relates to the field of surface profile measurement technology; according to five axial error parameters including eccentricity error, probe offset error, probe radius error, probe support rod tilt error and tilt error, five system errors, a five-bias error measurement model is established; the Monte Carlo method is used to generate the axial verticality and radial eccentricity data group of each stage of rotors of large-scale high-speed rotating equipment, the rotation angle of each stage of large-scale high-speed rotating equipment is rotated, and then the coaxiality parameters of multi-stage equipment are obtained, and the probability density function is obtained according to the drawn distribution function, and the probability relationship between the axial verticality and radial eccentricity tolerances of each stage of large-scale high-speed rotating equipment and the coaxiality tolerances of multi-stage equipment is obtained, so as to realize the allocation of tolerances of large-scale high-speed rotating equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of surface profile measurement, and is a tolerance allocation method for large rotary equipment of aero-engines based on five parameters and morphological filtering. Background Art

[0002] The assembly of aero-engines mainly involves the stacking assembly of its rotors and the assembly of large rotary equipment. In addition to the fact that the assembly quality of the rotors will significantly affect the overall performance of the engine, the large rotary equipment, which is also a rotating body, also has a huge impact on the overall performance of the engine. Therefore, the high-quality assembly of large rotary equipment and the reasonable allocation of its tolerances are also the basis for ensuring the overall assembly quality of aero-engines.

[0003] Similar to the rotor assembly, the coaxiality and perpendicularity of large rotary equipment are also the core basic indicators reflecting its static assembly performance. Exceeding the tolerance will cause obvious vibration when the engine is running at high speed. When the vibration reaches a certain level, it will cause rubbing between the rotor and the casing, directly leading to overall wear and even damage of the engine. Therefore, considering the five system errors existing during assembly and allocating tolerances to each component during the assembly process, supplemented by morphological filtering, can greatly reduce the pressure of dynamic balance and greatly improve the reliability of the engine. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art, the present invention provides a tolerance allocation method for large rotary equipment of aero-engines based on five parameters and morphological filtering.

[0005] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0006] A tolerance allocation method for large rotary equipment of aero-engines based on five parameters and morphological filtering, the method comprising the following steps:

[0007] Step 1: When measuring the eccentricity error, it causes the sampling angle to shift during the axial measurement of cylindrical rotating workpieces, and determine the actual sampling angle shift amount;

[0008] Step 2: During the measurement process, the measurement direction of the sensor cannot coincide with the sampling direction, resulting in a probe offset error of the sensor. The probe offset error of the sensor and the offset error are coupled, jointly causing the sampling angle to deviate. Determine the actual sampling angle deviation of the sensor;

[0009] Step 3: The radius error of the probe will be coupled into the measurement result. The radius error causes the measured value H of the axial profile perpendicularity to increase. Determine the deviation of the actual perpendicularity measurement value H' and the deviation of the surface runout value at the actual measurement point;

[0010] Step 4: There is a certain angle between the axis of the cylindrical rotating workpiece itself and the axis of the rotating spindle, resulting in the coupling of the tilt error of the workpiece into the measurement model. The tilt error causes the measured value of the axial profile perpendicularity to deviate. Determine the deviation of the actual perpendicularity measurement value;

[0011] Step 5: Based on five error parameters in the axial direction, including eccentricity error, probe offset error, probe radius error, probe support rod tilt error, and tilt error, which are five systematic errors, establish a five-offset error measurement model;

[0012] Step 6: Use the Monte Carlo method to generate data sets of the axial perpendicularity and radial eccentricity of the rotors at all levels of large high-speed rotating equipment. Rotate the rotation angle of all levels of large high-speed rotating equipment, and then obtain the coaxiality parameters of multi-level equipment. According to the drawn distribution function, calculate the probability density function, and obtain the probability relationship between the axial perpendicularity and radial eccentricity tolerances of all levels of large high-speed rotating equipment and the coaxiality tolerance of multi-level equipment, so as to realize the distribution of the tolerances of large high-speed rotating equipment.

[0013] Preferably, the specific content of Step 1 is as follows:

[0014] The machining error of the self-assembly surface causes the geometric center of the workpiece to be in a non-ideal position. The axis of the rotating spindle of the measuring device and the axis of the cylindrical rotating workpiece itself cannot be adjusted to an absolutely coincident state. During the measurement, there will be an eccentricity error in the cylindrical rotating workpiece. The eccentricity error causes the sampling angle to deviate during the axial measurement of the cylindrical rotating workpiece. The actual sampling angle deviation is expressed by the following formula:

[0015]

[0016] where e 0 is the initial eccentricity, α is the corresponding eccentric angle, r 0 is the fitting radius, θ' i is the actual sampling angle, and θ i is the ideal sampling angle.

[0017] Preferably, the specific content of Step 2 is as follows:

[0018] During the measurement process, the measurement direction of the sensor cannot coincide with the sampling direction, resulting in a probe offset error of the sensor. The probe offset error of the sensor and the offset error are coupled, jointly causing the sampling angle to deviate. The actual angle deviation is expressed by the following formula:

[0019] Δη i =sin -1 ((m j +p j sin(η ij -α j )) / r 0j )

[0020] Wherein, m j is the probe offset, O 2j is the instantaneous center of rotation generated by the probe offset, and Δθ ij is the offset angle of each sampling point on the cross section.

[0021] Preferably, step 3 is specifically as follows:

[0022] Meanwhile, when using the sensor for measurement, the measurement point is not the contact point between the probe and the cylindrical contour surface, but the center point of the spherical probe of the sensor. Therefore, the probe radius error r will be coupled into the measurement result, and the radius error causes the measured value H of the axial contour perpendicularity to be on the high side. The offset of the actual perpendicularity measurement value H' is expressed by the following formula:

[0023] ν i =H′-H=r

[0024] During the measurement, the spherical probe needs to deflect a certain angle when measuring the cylindrical contour causing coupling between the probe support rod tilt error and the probe radius error, resulting in the surface runout Δz i at the measurement point being on the high side. Then, the offset of the surface runout value at the actual measurement point is expressed by the following formula:

[0025]

[0026] Preferably, step 4 is specifically as follows:

[0027] Due to certain machining errors on the bottom surface of the cylindrical workpiece, there will be a certain deflection angle between the axis of the cylindrical rotating workpiece itself and the axis of the rotating spindle, resulting in the coupling of the workpiece tilt error in the measurement model. This error causes the measured value of the axial contour perpendicularity to deviate. The offset of the actual perpendicularity measurement value is expressed by the following formula:

[0028] When |θ i ′-β| is within the range of 0 to π:

[0029]

[0030] When |θ i ′ - β| is in the range of π to 2π:

[0031]

[0032] where r 0 is the sampling radius, γ and β are respectively the inclination angle of the geometric axis and the angle between the projection direction of the geometric axis on the measurement plane and the initial measurement direction;

[0033] In actual measurement, the sensor automatically compensates for the error caused by the radius of the probe, and couples in the tilt error of the probe support rod, which has a certain impact on the measurement result. Finally, the perpendicularity measurement model and the actual sampling angle are determined by the following formula:

[0034] When |θ i ′ - β| is in the range of 0 to π:

[0035]

[0036] When |θ i ′ - β| is in the range of π to 2π:

[0037]

[0038] where

[0039] Preferably, step 5 is specifically:

[0040] There are five error parameters affecting in the axial direction in the radial direction, namely eccentricity error, probe offset error, probe radius error, probe support rod tilt error and tilt error, a total of five systematic errors. The derivation of each error is similar to that in the axial direction. The five-offset error measurement model is expressed by the following formula:

[0041]

[0042] where p is the number of sampling cross-sections, the number of sampling points for each cross-section is n, P ij is the measurement point i of cross-section j, O 11 and O 1j are the measurement rotation centers of the bottom surface and cross-section j, and the geometric centers of the bottom surface and cross-section j of the measured part are O 21 and O 2j respectively, and the geometric axis inclination angle and the vertical guide inclination angle are γ and φ respectively;

[0043] e j and α j are respectively the eccentricity and eccentricity angle of cross-section j, γ is the aforementioned tilt error, β jis the angle between the major axis direction of the fitted ellipse and the initial measurement direction, and the minor axis and major axis of the fitted ellipse are r oj and r lj ; d j is the offset of the sensor probe itself, and the tilting errors of the horizontal and vertical guide rails are R j-v = L j ·tanw·sinτ ij and T j-v = z j ·tanφ·sinε ij causing the probe to deviate, resulting in the measurement line not passing through the measurement rotation center, but generating an instantaneous rotation center O 3j with the sampling angle; the linear component t j-m = z j ·tanφ·cosε ij of the vertical guide rail tilting error in the measurement direction will act on the measurement result; when the above errors exist, the probe radius r interacts with each error and also affects the measurement, where O 4j is the probe center; is the tilting error of the probe rod;

[0044] Performing a power series expansion on the above formula, using d j + L j tanw sinτ ij + z j tanφsinε ij + e j sin(θ ij - α j ) as the expansion parameter and omitting the high-order terms, the seven-offset error measurement model can be obtained as:

[0045]

[0046] Preferably, the surface measurement data of large-scale high-speed rotating equipment needs to be effectively filtered before parameter evaluation to improve the measurement accuracy.

[0047] An aero-engine rotor coaxiality stacking device based on a five-offset axial measurement model, the device includes:

[0048] A sampling angle offset acquisition module, which determines the actual sampling angle offset when the sampling angle deviates during the axial measurement of cylindrical rotating workpieces caused by eccentricity errors during measurement;

[0049] A sensor actual sampling angle offset acquisition module, wherein the sensor actual sampling angle offset acquisition module determines that the sensor's measurement direction cannot coincide with the sampling direction during the measurement process, resulting in a sensor probe offset error. The sensor probe offset error and the offset error are coupled, resulting in a sampling angle offset, thereby determining the sensor's actual sampling angle offset;

[0050] A runout value offset acquisition module, wherein the runout value offset acquisition module couples the probe radius error into the measurement result, wherein the radius error causes the axial profile verticality measurement value H to increase, and determines the offset of the actual verticality measurement value H' and the surface runout value offset at the actual measurement point;

[0051] A verticality measurement value offset acquisition module is provided. The verticality measurement value offset acquisition module determines the actual verticality measurement value offset because there is a certain deflection angle between the axis of the cylindrical rotary workpiece and the axis of the rotary spindle, which causes the tilt error of the workpiece to be coupled in the measurement model. The tilt error causes the axial profile verticality measurement value to be offset.

[0052] A five-offset error measurement model module, wherein the five-offset error measurement model module establishes a five-offset error measurement model according to five axial error parameters including eccentricity error, probe offset error, probe radius error, probe support rod tilt error and tilt error, five system errors;

[0053] An evaluation module, wherein the evaluation module uses the Monte Carlo method to generate axial verticality and radial eccentricity data sets of rotors of various stages of large-scale high-speed rotating equipment, rotates the rotation angles of various stages of large-scale high-speed rotating equipment, and then obtains the coaxiality parameters of multi-stage equipment. A probability density function is obtained based on the drawn distribution function to obtain the probability relationship between the axial verticality and radial eccentricity tolerances of various stages of large-scale high-speed rotating equipment and the coaxiality tolerances of multi-stage equipment, thereby realizing the allocation of tolerances of large-scale high-speed rotating equipment.

[0054] A computer-readable storage medium stores a computer program, which is executed by a processor to implement a tolerance allocation method for large rotating equipment of an aircraft engine based on five parameters and morphological filtering.

[0055] A computer device comprises a memory and a processor, wherein a computer program is stored in the memory. When the processor runs the computer program stored in the memory, the processor executes a tolerance allocation method for large rotating equipment of an aircraft engine based on five parameters and morphological filtering.

[0056] The present invention has the following beneficial effects:

[0057] The present invention addresses the problem of inaccurate measurement of large rotating equipment caused by the coupling among five systematic errors, namely eccentricity error, probe offset error, probe radius error, probe support rod tilt error, and tilt error, in a cylindricity measurement device. A corresponding five-system error perpendicularity measurement model is proposed and supplemented with a morphological filtering method to further improve measurement accuracy, thereby ensuring the assembly quality of large rotating equipment.

[0058] Regarding the error model proposed above, it can be seen that the sampling angles have the characteristic of uneven distribution. Therefore, a three-dimensional morphological filtering method that is more in line with the actual measurement and an intelligent evaluation method that conforms to the definition of coaxiality error are of great significance for improving the measurement and tolerance allocation of large high-speed rotating equipment. Brief Description of the Drawings

[0059] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0060] Figure 1 It is a schematic diagram of eccentricity error;

[0061] Figure 2 It is a schematic diagram of probe offset error;

[0062] Figure 3 It is a schematic diagram of probe radius error;

[0063] Figure 4 It is a schematic diagram of probe support rod tilt error;

[0064] Figure 5 It is a schematic diagram of tilt error;

[0065] Figure 6 It is a schematic diagram of the five-parameter error model;

[0066] Figure 7 Coaxiality simulation results of a small-sized stepped shaft;

[0067] Figure 8 Coaxiality simulation results of a large-sized stepped shaft;

[0068] Figure 9 Flow chart of the tolerance allocation method for large rotating equipment based on five parameters and morphological filtering. Detailed Embodiments

[0069] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work shall fall within the protection scope of the present invention.

[0070] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0071] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0072] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0073] The present invention is described in detail below in conjunction with specific embodiments. Specific Embodiment 1:

[0075] According to Figures 1 to 9 As shown, the specific optimization technical solution adopted by the present invention to solve the above technical problems is: The present invention relates to a tolerance allocation method for large rotary equipment of aero-engines based on five parameters and morphological filtering.

[0076] A tolerance allocation method for large rotary equipment of aero-engines based on five parameters and morphological filtering, the method comprising the following steps:

[0077] Step 1: When measuring the eccentricity error, the sampling angle during the axial measurement of cylindrical rotary workpieces is shifted, and the actual sampling angle shift amount is determined;

[0078] Step 2: During the measurement process, the measuring direction of the sensor cannot coincide with the sampling direction, resulting in the sensor's probe offset error. The sensor's probe offset error and offset error are coupled, resulting in a sampling angle offset. The actual sampling angle offset of the sensor is determined.

[0079] Step 3: The probe radius error is coupled into the measurement result. The radius error causes the axial profile verticality measurement value H to increase. The offset of the actual verticality measurement value H' and the offset of the surface runout value at the actual measuring point are determined.

[0080] Step 4: There is a certain deflection angle between the axis of the cylindrical rotary workpiece and the axis of the rotary spindle, which causes the tilt error of the workpiece to be coupled in the measurement model. The tilt error causes the axial profile verticality measurement value to be offset, and the actual verticality measurement value offset is determined;

[0081] Step 5: Establish a five-offset error measurement model based on five axial error parameters including eccentricity error, probe offset error, probe radius error, probe support rod tilt error and tilt error;

[0082] Step 6: Use the Monte Carlo method to generate the axial verticality and radial eccentricity data set of the rotors of each stage of large-scale high-speed rotating equipment, rotate the rotation angle of each stage of large-scale high-speed rotating equipment, and then obtain the coaxiality parameters of the multi-stage equipment. According to the drawn distribution function, the probability density function is obtained to obtain the probability relationship between the axial verticality and radial eccentricity tolerances of each stage of large-scale high-speed rotating equipment and the coaxiality tolerance of the multi-stage equipment, so as to realize the allocation of tolerances of large-scale high-speed rotating equipment. Specific embodiment 2:

[0084] The difference between the second embodiment of the present application and the first embodiment is that:

[0085] The step 1 is specifically as follows:

[0086] This method takes into account that when measuring rotating components, the machining error of the assembly surface causes the geometric center of the workpiece to be in a non-ideal position. At the same time, since the axis of the rotating spindle of the measuring device and the axis of the cylindrical rotating workpiece itself cannot be adjusted to an absolutely coincident state, there will be an eccentric error in the cylindrical rotating workpiece during measurement. Figure 1 As shown in the figure, the machining error of the assembly surface itself causes the geometric center of the workpiece to be in a non-ideal position. The axis of the rotating spindle of the measuring device and the axis of the cylindrical rotating workpiece itself cannot be adjusted to an absolutely coincident state. During measurement, the cylindrical rotating workpiece will have an eccentric error. The eccentric error causes the sampling angle of the cylindrical rotating workpiece to shift during axial measurement. The actual sampling angle offset is expressed by the following formula:

[0087]

[0088] Among them, e 0 is the initial eccentricity, α is the corresponding eccentric angle, r 0 is the fitting radius, θ' i is the actual sampling angle, θ i is the ideal sampling angle. Specific Embodiment Three:

[0090] The difference between the third embodiment of this application and the second embodiment is only that:

[0091] The specific step 2 is:

[0092] During the measurement process, the measurement direction of the sensor cannot coincide with the sampling direction, resulting in a probe offset error of the sensor. As Figure 2 shown, the probe offset error of the sensor and the offset error are coupled, jointly causing the sampling angle to deviate. The actual angle offset is expressed by the following formula:

[0093] Δη i = sin -1 ((m j + p j sin(η ij - α j )) / r 0j )

[0094] Among them, m j is the probe offset, O 2j is the instantaneous center of rotation generated by the probe offset, and Δθ ij is the offset angle of each sampling point on the cross-section. Specific Embodiment Four:

[0096] The difference between the fourth embodiment of this application and the third embodiment is only that:

[0097] The specific step 3 is:

[0098] At the same time, when applying the sensor for measurement, the measurement point is not the contact point between the probe and the cylindrical contour surface, but the center point of the spherical probe of the sensor. Therefore, the probe radius error r will be coupled into the measurement result. As Figure 3 shown. The radius error causes the measured value H of the axial contour perpendicularity to be on the high side. The offset of the actual perpendicularity measured value H' is expressed by the following formula:

[0099] ν i = H′ - H = r

[0100] During the measurement, the spherical probe needs to be deflected by a certain angle when measuring the cylindrical contour causing coupling between the probe support tilt error and the probe radius error, resulting in the surface runout Δz at the measurement point iis on the high side (schematic diagram as Figure 4 shown), then the surface runout value offset at the actual measurement point is expressed by the following formula:

[0101] Specific Embodiment Five:

[0103] The difference between Embodiment Five and Embodiment Four of this application is only that:

[0104] Step 4 is specifically:

[0105] Due to certain machining errors on the bottom surface of the cylindrical workpiece, there will be a certain included angle between the axis of the cylindrical rotating workpiece itself and the axis of the rotating spindle, resulting in the coupling of the tilt error of the workpiece in the measurement model. This error causes an offset in the measured value of the axial profile perpendicularity (schematic diagram as Figure 5 shown), and the offset of the actual perpendicularity measurement value is expressed by the following formula:

[0106] When |θ i ′ - β| is in the range of 0 to π:

[0107]

[0108] When |θ i ′ - β| is in the range of π to 2π:

[0109]

[0110] Wherein, r 0 is the sampling radius, γ and β are respectively the geometric axis tilt angle and the included angle between the projection direction of the geometric axis on the measurement plane and the initial measurement direction;

[0111] In actual measurement, the sensor automatically compensates for the error caused by the radius of the probe, and couples in the tilt error of the probe rod, which has a certain impact on the measurement result. Finally, the perpendicularity measurement model and the actual sampling angle are determined by the following formula:

[0112] When |θ i ′ - β| is in the range of 0 to π:

[0113]

[0114] When |θ i ′ - β| is in the range of π to 2π:

[0115]

[0116] Wherein, Specific Embodiment Six:

[0118] The difference between the sixth embodiment and the fifth embodiment of this application lies only in that:

[0119] Step 5 is specifically as follows:

[0120] There are five error parameters affecting in the axial direction in the radial direction, namely five systematic errors: eccentricity error, probe offset error, probe radius error, probe strut tilt error, and tilt error. The derivation of each error is similar to that in the axial direction. The five-offset error measurement model is determined and expressed by the following formula:

[0121]

[0122] Among them, p is the number of sampling cross-sections, the number of sampling points for each cross-section is n, P ij is the measurement point i of cross-section j, O 11 and O 1j are the measurement rotation centers of the bottom surface and cross-section j, and the geometric centers of the bottom surface and cross-section j of the measured part are O 21 and O 2j respectively; the geometric axis tilt angle and the vertical guide tilt angle are γ and φ respectively;

[0123] e j and α j are the eccentricity and eccentricity angle of cross-section j respectively, γ is the aforementioned tilt error, β j is the angle between the long axis direction of the fitted ellipse of the cross-section and the initial measurement direction, and the short axis and long axis of the fitted ellipse are r oj and r lj respectively; d j is the offset of the sensor probe itself, and the horizontal and vertical guide tilt errors are R j-v =L j ·tanw·sinτ ij and T j-v =z j ·tanφ·sinε ij cause the probe to offset, resulting in the measurement line not passing through the measurement rotation center but generating an instantaneous rotation center O 3j along with the sampling angle; the linear component t j-m =z j ·tanφ·cosε ij of the vertical guide tilt error in the measurement direction will act on the measurement result; when the above errors exist, the probe radius r interacts with each error and will also affect the measurement, where O 4j is the probe center; is the probe strut tilt error;

[0124] Expand the above formula into a power series, with d j +L j tanw sinτ ij +zj tanφsinε ij +e j sin(θ ij -α j ) is the expansion parameter, and by omitting the high-order terms, the seven-offset error measurement model can be obtained as follows:

[0125] Specific Embodiment Seven:

[0127] The difference between Embodiment Seven and Embodiment Six of this application is only that:

[0128] Step 6 is specifically as follows:

[0129] Apply the Monte Carlo method to generate 10,000 groups of axial perpendicularity and radial eccentricity data for each level of the rotor of the large high-speed rotating equipment. Rotate the rotation angle of each level of the large high-speed rotating equipment, and then obtain 10,000 groups of coaxiality parameters of the multi-level equipment. According to the drawn distribution function, the probability density function is obtained, and the probability relationship between the axial perpendicularity and radial eccentricity tolerances of each level of the large high-speed rotating equipment and the coaxiality tolerance of the multi-level equipment is obtained, so as to realize the distribution of the tolerances of the large high-speed rotating equipment.

[0130] The surface measurement data of the large high-speed rotating equipment needs to be effectively filtered before parameter evaluation to further improve the measurement accuracy. Compared with the median filtering, envelope filtering such as morphological filtering filters from the functional aspect and can simulate the mating situation of the contact surface during the assembly of the low-pressure turbine shaft. Most of the domestic and foreign scholars' research on morphological filters focuses on two-dimensional contours and does not consider the influence of the existence of measurement system errors on the true sampling angle distribution.

[0131] For the error model proposed above, it can be seen that its sampling angle has the characteristic of uneven distribution. Therefore, a three-dimensional morphological filtering that is more in line with the actual measurement and an intelligent evaluation method that conforms to the definition of coaxiality error are of great significance for improving the measurement and tolerance distribution of large high-speed rotating equipment.

[0132] The surface measurement data of the large high-speed rotating equipment needs to be effectively filtered before parameter evaluation to improve the measurement accuracy. Specific Embodiment Eight:

[0134] The difference between Embodiment Eight and Embodiment Seven of this application is only that:

[0135] The present invention provides an aero-engine rotor coaxiality stacking device based on a five-offset axial measurement model, and the device includes:

[0136] Sampling angle offset acquisition module, which determines the actual sampling angle offset when the sampling angle during the axial measurement of cylindrical rotating workpieces is offset due to the eccentricity error during measurement.

[0137] Sensor actual sampling angle offset acquisition module, which determines the actual sampling angle offset of the sensor when the measurement direction of the sensor cannot coincide with the sampling direction during the measurement process, resulting in a probe offset error of the sensor. The probe offset error of the sensor and the offset error are coupled, jointly causing the sampling angle to be offset.

[0138] Runout value offset acquisition module, which determines the offset of the actual perpendicularity measurement value H and the surface runout value offset at the actual measurement point when the radius error of the probe is coupled into the measurement result, and the radius error causes the axial profile perpendicularity measurement value H to increase.

[0139] Perpendicularity measurement value offset acquisition module, which determines the actual perpendicularity measurement value offset when there is a certain angle between the axis of the cylindrical rotating workpiece itself and the axis of the rotating spindle, resulting in the coupling of the tilt error of the workpiece into the measurement model, and the tilt error causes the axial profile perpendicularity measurement value to be offset.

[0140] Five-offset error measurement model module, which establishes a five-offset error measurement model based on five error parameters in the axial direction, including eccentricity error, probe offset error, probe radius error, probe support rod tilt error, and tilt error, which are five systematic errors.

[0141] Evaluation module, which uses the Monte Carlo method to generate data sets of the axial perpendicularity and radial eccentricity of the rotors at all levels of large high-speed rotating equipment, rotates the rotation angle of all levels of large high-speed rotating equipment, and then obtains the coaxiality parameters of multi-level equipment. According to the drawn distribution function, the probability density function is obtained, and the probability relationship between the axial perpendicularity and radial eccentricity tolerances of all levels of large high-speed rotating equipment and the coaxiality tolerance of multi-level equipment is obtained, so as to realize the distribution of the tolerances of large high-speed rotating equipment. Specific Example Nine:

[0142] The difference between the ninth embodiment of this application and the eighth embodiment is only that:

[0143] The present invention provides a computer-readable storage medium, on which a computer program is stored, and the program is executed by a processor to implement a tolerance distribution method for large rotating equipment of an aero-engine based on five parameters and morphological filtering. Specific Example Ten:

[0145] The difference between the tenth embodiment of this application and the ninth embodiment is only that:

[0146] The present invention provides a computer device, including a memory and a processor. A computer program is stored in the memory. When the processor runs the computer program stored in the memory, the processor executes a tolerance allocation method for large rotary equipment of an aero-engine based on five parameters and morphological filtering. Specific Embodiment XI:

[0148] The difference between Embodiment XI and Embodiment X of this application lies only in that:

[0149] The verticality measurement model and the actual sampling angles are respectively

[0150]

[0151]

[0152] For the model given above, 10,000 groups of axial verticality and radial eccentricity data of rotors at all levels of large high-speed rotary equipment can be generated according to the Monte Carlo method. By rotating the rotation angles of large high-speed rotary equipment at all levels, 10,000 groups of coaxiality parameters of multi-level equipment can be obtained. According to the drawn distribution function, the probability density function is obtained, and the probability relationship between the axial verticality and radial eccentricity tolerances of large high-speed rotary equipment at all levels and the coaxiality tolerance of multi-level equipment is realized, so as to achieve the allocation of tolerances for large high-speed rotary equipment.

[0153] For the sampling angle distribution under the five-parameter model, analysis can be carried out to give the true sampling angle distribution function. Subsequently, a morphological filter based on non-equidistant sampling angles can be designed by its center line and envelope filtering technology, which can reduce the filtering error to a certain extent, thereby improving the filtering accuracy of the circular contour of large rotary equipment.

[0154] Analyze the effectiveness of the non-equidistant three-dimensional morphological filter. Use the surface contour data of stepped shafts sampled at equal intervals and non-equidistant intervals respectively, and process them with the morphological filter model given in the present invention. When the alpha ball in morphological filtering rolls over the inner surface of the stepped shaft, the radius of the alpha ball should be smaller than the contour radius. Alpha balls with radii of 59.5 mm, 39.5 mm and 29.5 mm, 19.5 mm are selected for the large and small stepped shafts respectively. The coaxiality simulation results under equal-interval filtering and non-equidistant filtering can be obtained under different error levels as Figure 7 、 8 shown.

[0155] Note: The theoretical values of the coaxiality errors of the large and small stepped shafts are both 2.29 μm.

[0156] Group 1: e = 1 μm, γ = 10″, d = 50 μm, r = 2.5 mm, w = 1″,

[0157] Group 2: e = 5μm, γ = 30″, d = 100μm, r = 2mm, w = 3″,

[0158] Group 3: e = 10μm, γ = 60″, d = 200μm, r = 1.5mm, w = 8″,

[0159] Group 4: e = 20μm, γ = 120″, d = 300μm, r = 1mm, w = 12″,

[0160] Group 5: e = 30μm, γ = 200″, d = 500μm, r = 0.5mm, w = 20″,

[0161] The morphological filter can smooth the contour data and filter out noise. It can be seen from the simulation results that when the error magnitude is relatively small at 1, the equal-interval and non-equal-interval three-dimensional morphological filtering accuracies of stepped shafts with different sizes are basically the same. When the error magnitude increases, the coaxiality errors obtained after processing by the two filtering methods are gradually increasing. Compared with the equal-interval filtering, the coaxiality measurement accuracy of stepped shafts with different sizes obtained after non-equal-interval morphological filtering is gradually improving. For example, when the error magnitude is 5, the coaxiality accuracies of the large and small stepped shafts are improved by 2.34μm and 2.07μm respectively, which proves the effectiveness of the non-equal-interval three-dimensional morphological filter for large offset errors.

[0162] In view of the problem that the inaccurate measurement of large rotary equipment is caused by the coupling among five systematic errors, namely the eccentricity error, probe offset error, probe radius error, probe support rod tilt error, and tilt error, in the cylindricity measurement device, the present invention proposes a corresponding five-system error perpendicularity measurement model and supplements it with a morphological filtering method to further improve the measurement accuracy, so as to ensure the assembly quality of large rotary equipment. The distribution process is as Figure 9 shown.

[0163] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or N embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples. Furthermore, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" can explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "N" is at least two, such as two, three, etc., unless otherwise specifically defined. Any process or method description represented in a flowchart or described in other ways herein can be understood as representing a module, segment, or part of code including one or more N executable instructions for implementing a customized logical function or process, and the scope of the preferred embodiments of the present invention includes additional implementations, where the functions can be executed in a manner not shown or discussed, including in a substantially simultaneous manner according to the functions involved or in a reverse order, which should be understood by those skilled in the art of the embodiments of the present invention. The logic and / or steps represented in a flowchart or described in other ways herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be specifically implemented in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other systems that can fetch and execute instructions from the instruction execution system, apparatus, or device), or in combination with these instruction execution systems, apparatuses, or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transmit a program for use by or in combination with an instruction execution system, apparatus, or device. More specific examples (non-exhaustive list) of computer-readable media include the following: an electrical connection portion (electronic device) having one or N wirings, a portable computer diskette (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM).In addition, the computer-readable medium can even be paper or other suitable media on which the program can be printed, because the program can be obtained electronically, for example, by optically scanning the paper or other media, followed by editing, interpretation, or other appropriate processing as necessary, and then stored in a computer memory. It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, any one or a combination of the following techniques well known in the art can be used: discrete logic circuits having logic gate circuits for implementing logical functions on data signals, application-specific integrated circuits having appropriate combinational logic gate circuits, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), and the like.

[0164] Those of ordinary skill in the art can understand that all or part of the steps carried by the methods in the above embodiments can be completed by instructing relevant hardware through a program. The program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiments. In addition, in each embodiment of the present invention, the functional units can be integrated into a processing module, or each unit can exist physically alone, or two or more units can be integrated into one module. The above integrated module can be implemented in the form of hardware or in the form of a software functional module. When the above integrated module is implemented in the form of a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0165] The above is only a preferred embodiment of a tolerance allocation method for large rotary equipment of aeroengines based on five parameters and morphological filtering. The protection scope of a tolerance allocation method for large rotary equipment of aeroengines based on five parameters and morphological filtering is not limited to the above embodiments. All technical solutions falling within this concept belong to the protection scope of the present invention. It should be noted that for those skilled in the art, several improvements and changes made without departing from the principle of the present invention should also be regarded as within the protection scope of the present invention.

Claims

1. A tolerance allocation method for large rotary equipment of aero-engines based on five parameters and morphological filtering, Characterized in that: The method comprises the following steps: Step 1: When measuring the eccentricity error, the sampling angle during the axial measurement of cylindrical rotary workpieces is shifted, and the actual sampling angle shift amount is determined; Step 2: During the measurement process, the measurement direction of the sensor cannot coincide with the sampling direction, resulting in a probe offset error of the sensor. The probe offset error of the sensor and the offset error are coupled, jointly causing the sampling angle to shift, and the actual sampling angle shift amount of the sensor is determined; Step 3: The probe radius error is coupled into the measurement result, and the radius error causes the measured value H of the axial profile perpendicularity to increase. The offset amount of the actual perpendicularity measurement value H' and the offset amount of the surface runout value at the actual measurement point are determined; Step 4: There is a certain included angle between the axis of the cylindrical rotary workpiece itself and the axis of the rotary main shaft, resulting in the coupling of the tilt error of the workpiece into the measurement model. The tilt error causes the measured value of the axial profile perpendicularity to shift, and the offset amount of the actual perpendicularity measurement value is determined; Step 5: According to five error parameters in the axial direction, including eccentricity error, probe offset error, probe radius error, probe support rod tilt error, and tilt error, five systematic errors, a five-offset error measurement model is established; Step 6: The Monte Carlo method is used to generate the axial perpendicularity and radial eccentricity data sets of the rotors at all levels of the large high-speed rotary equipment. The rotation angle of the large high-speed rotary equipment at all levels is rotated, and then the coaxiality parameters of the multi-level equipment are obtained. According to the drawn distribution function, the probability density function is obtained, and the probability relationship between the axial perpendicularity and radial eccentricity tolerances of the large high-speed rotary equipment at all levels and the coaxiality tolerance of the multi-level equipment is obtained, realizing the tolerance allocation of the large high-speed rotary equipment.

2. A tolerance allocation method for large rotary equipment of aero-engines based on five parameters and morphological filtering according to claim 1, Characterized in that: The specific content of the said Step 1 is: The machining error of the self-assembly surface causes the geometric center of the workpiece to be in a non-ideal position. The axis of the rotary main shaft of the measuring device and the axis of the cylindrical rotary workpiece itself cannot be adjusted to an absolutely coincident state. When measuring, there will be an eccentricity error in the cylindrical rotary workpiece. The eccentricity error causes the sampling angle during the axial measurement of the cylindrical rotary workpiece to shift. The actual sampling angle shift amount is expressed by the following formula: where, e 0 is the initial eccentricity, α is the corresponding eccentric angle, r 0 is the fitting radius, θ' i is the actual sampling angle, θ i is the ideal sampling angle.

3. A tolerance allocation method for large rotary equipment of aero-engines based on five parameters and morphological filtering according to claim 2, Characterized in that: The specific content of the said Step 2 is: During the measurement process, the measurement direction of the sensor cannot coincide with the sampling direction, resulting in a probe offset error of the sensor. The probe offset error of the sensor and the offset error are coupled, jointly causing the sampling angle to shift. The actual angle shift amount is expressed by the following formula: Δη i = sin -1 ((m j + p j sin(η ij - α j )) / r 0j ) where m j is the probe offset, O 2j is the instantaneous center of rotation generated by the probe offset, and Δθ ij is the offset angle of each sampling point of the cross-section.

4. A tolerance allocation method for large rotary equipment of aero-engines based on five parameters and morphological filtering according to claim 3, Characterized in that: The specific content of the said Step 3 is: When using a sensor for measurement, the measurement point is not the contact point between the probe and the cylindrical contour surface, but the center point of the spherical probe of the sensor. Therefore, the radius error r of the probe will be coupled into the measurement result, and the radius error causes the measured value H of the axial contour perpendicularity to be on the high side. The offset of the actual perpendicularity measurement value H' is expressed by the following formula: ν i = H′ - H = r In measurement, when a spherical probe measures a cylindrical profile, the probe rod needs to be deflected by a certain angle which causes coupling between the probe support rod tilt error and the probe radius error, resulting in a surface runout Δz i at the measurement point being on the high side. Then, the offset of the surface runout value at the actual measurement point is expressed by the following formula:

5. A tolerance allocation method for large rotary equipment of an aero-engine based on five parameters and morphological filtering according to claim 4, characterized in that: The specific steps of step 4 are as follows: Due to certain machining errors on the bottom surface of the cylindrical workpiece, there will be a certain angle deviation between the axis of the cylindrical rotary workpiece itself and the axis of the rotary spindle, resulting in the coupling of the tilt error of the workpiece into the measurement model. This error causes the measured value of the axial contour perpendicularity to deviate. The offset of the actual perpendicularity measurement value is expressed by the following formula: When |θ′ i -β| is in the range from 0 to π: When |θ′ i - β| is in the range of π to 2π: where r 0 is the sampling radius, and γ and β are the inclination angle of the geometric axis and the angle between the projection direction of the geometric axis on the measurement plane and the initial measurement direction, respectively; In actual measurement, the sensor automatically compensates for the error caused by the probe radius, and the tilt error of the probe rod is coupled in, which has a certain impact on the measurement result. Finally, the perpendicularity measurement model and the actual sampling angle are determined by the following formula: When |θ′ i - β| is in the range of 0 to π: When |θ′ i - β| is in the range of π to 2π: Among them, 6. A tolerance allocation method for large rotary equipment of an aero-engine based on five parameters and morphological filtering according to claim 5, characterized in that: The specific steps of step 5 are as follows: There are five error parameters shown axially in the radial direction, namely eccentricity error, probe offset error, probe radius error, probe rod tilt error, and tilt error. The derivation of each error is similar to that in the axial direction. The five-offset error measurement model is determined by the following formula: where i is the number of sampling cross-sections, the number of sampling points for each cross-section is n, O 11 and O 1j are the measured rotation centers of the bottom surface and cross-section j, and the geometric centers of the bottom surface of the measured part and cross-section j are O 21 and O 2j respectively, and the geometric axis inclination angle and the vertical guide rail inclination angle are γ and φ respectively; e j and α j are respectively the eccentricity and the eccentric angle of section j, γ is the aforementioned tilt error, and β j is the angle between the major axis direction of the fitted ellipse of the section and the initial measurement direction. The minor axis and the major axis of the fitted ellipse are r oj and r lj ; d j is the offset of the sensor probe itself. The tilt errors of the horizontal and vertical guide rails are respectively R j-v = L j ·tanw·sinτ ij and T j-v = z j ·tanφ·sinε ij which cause the probe to offset, resulting in the measurement line not passing through the measurement rotation center but generating an instantaneous rotation center O 3j with the sampling angle; the linear component t j-m = z j ·tanφ·cosε ij of the tilt error of the vertical guide rail in the measurement direction will act on the measurement result; when the above errors exist, the probe radius r interacts with each error and will also affect the measurement, where O 4j is the probe center; is the tilt error of the probe support rod; Perform a power series expansion on the above formula, with as the expansion parameter, and omitting the high-order terms, the seven-offset error measurement model can be obtained as follows:

7. A tolerance allocation method for large rotary equipment of an aero-engine based on five parameters and morphological filtering according to claim 6, characterized in that: The surface measurement data of large high-speed rotary equipment needs to be effectively filtered before parameter evaluation to improve the measurement accuracy.

8. An aero-engine rotor coaxiality stacking device based on a five-offset axial measurement model, characterized in that: The device includes: A sampling angle offset acquisition module, which determines the actual sampling angle offset when the sampling angle of the axial measurement of the cylindrical rotary workpiece is offset during the measurement of the eccentricity error; A sensor actual sampling angle offset acquisition module, which determines the actual sampling angle offset of the sensor when the measurement direction of the sensor cannot coincide with the sampling direction during the measurement process, resulting in a probe offset error of the sensor. The probe offset error of the sensor and the offset error are coupled, jointly causing the sampling angle to deviate; A runout value offset acquisition module, which determines the offset of the actual perpendicularity measurement value H' and the surface runout value offset at the actual measurement point when the radius error of the probe is coupled into the measurement result, and the radius error causes the measured value H of the axial contour perpendicularity to increase; Verticality measurement value offset acquisition module. When there is a certain angular deviation between the axis of the cylindrical rotating workpiece itself and the axis of the rotating spindle, the tilt error of the workpiece is coupled into the measurement model, and the tilt error causes the verticality measurement value of the axial profile to deviate, so as to determine the actual verticality measurement value offset. Five-offset error measurement model module. The five-offset error measurement model module establishes a five-offset error measurement model according to five axial error parameters, including five systematic errors: eccentricity error, probe offset error, probe radius error, probe support rod tilt error, and tilt error. Evaluation module. The evaluation module uses the Monte Carlo method to generate axial verticality and radial eccentricity data sets of rotors at all levels of large high-speed rotating equipment, rotates the rotation angles of large high-speed rotating equipment at all levels, and then obtains the coaxiality parameters of multi-level equipment. According to the drawn distribution function, the probability density function is obtained, and the probability relationship between the axial verticality and radial eccentricity tolerances of large high-speed rotating equipment at all levels and the coaxiality tolerance of multi-level equipment is obtained, so as to realize the distribution of tolerances of large high-speed rotating equipment.

9. A computer-readable storage medium, on which a computer program is stored, characterized in that, when the program is executed by a processor, it is used to implement a method for tolerance allocation of a large rotating equipment of an aero-engine based on five parameters and morphological filtering as described in any one of claims 1-7.

10. A computer device, characterized in that, it includes a memory and a processor. A computer program is stored in the memory. When the processor runs the computer program stored in the memory, the processor executes a method for tolerance allocation of a large rotating equipment of an aero-engine based on five parameters and morphological filtering as described in any one of claims 1-7.

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