Tenon morphology contour detection method and contour tolerance, pitch and cross-rod distance evaluation method

Abstract

The invention discloses a tenon morphology contour detection method and a contour tolerance, tooth pitch and cross-rod distance evaluation method in the technical field of aero-engine turbine blade detection, and the method achieves the spatial scanning of the tenon morphology contour through a four-axis coordinate device and a confocal spectrum sensor, collects data points, and can achieve the non-contact detection of the tenon morphology contour. The actual contour of the appearance contour of the tenon is obtained, the detection efficiency is higher, meanwhile, the surface of the tenon cannot be damaged, high-precision and high-efficiency detection of the appearance contour of the tenon is achieved, and the defects that current tenon measurement adopts manual operation, precision is not high, and digitization cannot be achieved are overcome. The detection requirements of large size curvature, high precision and complex evaluation parameters of the blade tenon of the aero-engine can be met at the same time.

Description

Technical Field

[0001] The invention relates to the technical field of aero-engine turbine blade detection, in particular to a tenon profile detection method and a profile degree, tooth pitch and cross-bar pitch evaluation method. Background Art

[0002] Aircraft engine turbine blades (hereinafter referred to as turbine blades) are key components of aircraft engines. They are key structural parts that withstand high-speed rotation, high temperature, high pressure and complex stress environments. Their quality directly affects the reliability, safety and performance of the engine.

[0003] Fir-tree-shaped tenon (hereinafter referred to as tenon) structure is widely used in aircraft engines to connect turbine disks and blades, thanks to the fir-tree-shaped structure's small size, multiple contact surfaces, high strength, and easy maintenance.

[0004] The tenon of turbine blades has the characteristics of withstanding high temperature, high pressure, high load and extremely high processing precision during operation. Its geometric structure is complex and some dimensions have high detection and precision requirements. For example, the precision requirement of the working surface is ≤9μm, and the tolerance band shows a continuous change trend. In the actual manufacturing process, the tenon part is usually processed by high-precision profiling grinding technology.

[0005] Currently, there are technologies on the market that use contact detection methods such as three-dimensional coordinate measuring machines and profilometers to scan the tenon profile using tiny probes. Due to the small R profile of the tenon, a probe with a diameter of 0.5mm or less must be customized to complete the scanning task. The scanning speed generally does not exceed 2mm / s. The physical rigidity of the tiny probe is poor, and the accuracy loss is serious. The accuracy and efficiency cannot meet the requirements of tenon detection. At the same time, the tiny probe is basically equivalent to a needle tip structure, and there is a risk of scratching the surface of the part.

[0006] Based on this, the present invention designs a tenon profile detection method and a profile, tooth pitch, and cross-rod spacing evaluation method to solve the above problems. Summary of the invention

[0007] To achieve the above object, the present invention provides the following technical solution: a tenon profile detection method, using a 4-axis coordinate device and a confocal spectrum sensor to achieve tenon profile scanning and acquisition and non-contact optical detection of spatial points, comprising the following steps:

[0008] S1, confocal spectral sensor focus error compensation and indication error compensation;

[0009] S2, converting the theoretical data of the tenon morphology profile into a theoretical data set of the tenon morphology profile;

[0010] The theoretical data of tenon profile include theoretical profile and tolerance band curve;

[0011] The theoretical data set includes the theoretical values, upper tolerance and lower tolerance data of points on the theoretical contour;

[0012] S3, refer to the specification for establishing the coordinate system of the tenon of an aviation blade to establish the coordinate system of the tenon;

[0013] S4, after the optical parameters of the confocal spectral sensor are adjusted, a non-contact optical scan of the tenon profile is performed to obtain the actual tenon profile.

[0014] As a further solution of the present invention, in step S2, when the theoretical data of the tenon profile does not contain a complete tolerance band curve, it is necessary to obtain a complete tolerance band curve through a tolerance continuous change transition calculation, and the tolerance value of each two adjacent points in the transition area is equal to the ratio of the point distance to the tolerance difference. The specific calculation method is expressed as:

[0015]

[0016] Where: x1, x2, y1, y2 represent the X and Y coordinates of each adjacent point, δs represents the distance between two adjacent points, S represents the total distance of all points in the transition area, LT1, LT2 represent the original tolerance values ​​of the transition area points, and LT' represents the calculated transition tolerance value.

[0017] As a further solution of the present invention, in step S2, by projecting each point in the theoretical profile to the upper and lower tolerance zones in the vector direction, calculating the intersection points one by one and calculating the distance to define the tolerance value, the data is aggregated into a theoretical data set with tolerances in a unified format of X, Y, Z, I, J, K, UT, and LT;

[0018] Among them, X, Y, and Z represent the coordinates of the point, I, J, and K represent the vector of the point, UT represents the upper tolerance, and LT represents the lower tolerance.

[0019] As a further solution of the present invention, in step S3, when establishing the coordinate system of the tenon, a contact probe having a diameter equal to the diameter of the roller is used. The specific method for establishing the coordinate system of the tenon is as follows:

[0020] S31, find the center position of the probe on the tenon through three-dimensional simulation centering perception in the direction of the front edge and the rear edge of the tenon, and calculate the coordinates of the roller contact point through trigonometric function relationship. There are 4 points in total, which are represented as L1, L2, R1, R2, and the measuring point X1 of the end face of the tenon rear edge;

[0021] S32, use the four contact points of the tenon L1, L2, R1, and R2 to calculate the axis of the plane in which they are located, with the orientation being the blade stacking axis and the direction being pointing to the blade tip, and establish the origin of the Z axis;

[0022] S33, using the connecting line of L1 and L2 and the connecting line of R1 and R2 to calculate the midline to establish the axis, the direction is toward the trailing edge of the blade, and the origin of the Y axis is established;

[0023] S34, use point X1 to establish the X origin.

[0024] As a further solution of the present invention, in step S4, when the tenon profile is non-contact optically scanned, the tenon profile is symmetrically divided into two parts in the tenon width direction.

[0025] A method for evaluating the profile of a tenon of an aero-engine turbine blade, applicable to the above-mentioned non-contact detection method for the profile of a tenon of an aero-engine turbine blade, comprises the following steps:

[0026] S51, dividing the actual contour of the tenon topography into two parts: an overall contour and a working surface contour;

[0027] S52, using Gaussian least squares method to calculate the deviation and perform fitting processing on the overall profile obtained in step S51 to obtain an overall best fitting curve;

[0028] S53, based on the overall best fitting curve, the working surface contour obtained in step S51 is used to calculate the deviation and fitting processing again using the quadratic Gaussian least squares method to obtain the best fitting curve of the working surface, and the best fitting curve of the working surface is compared with the tolerance band curve and the theoretical contour to evaluate the tenon contour.

[0029] A method for evaluating the pitch of a tenon of an aeroengine turbine blade, applicable to the above-mentioned non-contact detection method for the tenon profile of an aeroengine turbine blade, comprises the following steps:

[0030] S61, importing the actual topography profile of the tenon obtained in step S4 into the tenon analysis software, and establishing two sets of virtual roller circles, where the diameter of the roller is the theoretical roller diameter required by the technology;

[0031] S62, positioning the virtual roller circle to the real roller position in the actual topographic profile of the tenon, and obtaining the first group of roller lower contact points L1, R1 and the second group of roller upper contact points L2, R2;

[0032] S63, respectively calculating the center line LINE1 and the midpoint O1 of the first group of rollers, the center line LINE2 and the midpoint O2 of the second group of rollers, and calculating the fitting line LINE3 of LINE1 and LINE2, and the midpoint O3 of O1 and O2;

[0033] S64, establish a two-dimensional pitch evaluation coordinate system with LINE3 as the X axis and 03 as the origin of X and Y;

[0034] S65, rotating the tooth pitch evaluation coordinate system by the process angle α according to the requirements on the tenon process drawing, and evaluating the left tooth distance LC and the right tooth distance RC respectively.

[0035] A method for evaluating the span of tenons of turbine blades of aircraft engines, applicable to the tenon profile detection method according to claim 1, characterized in that it comprises the following steps:

[0036] S71, importing the actual topography profile of the tenon obtained in step S4 into the tenon analysis software, establishing two virtual roller circles, and the diameter of the roller is the theoretical roller diameter required by the technology;

[0037] S72, positioning the virtual roller circle to the real roller position in the actual topographic profile of the tenon;

[0038] S73, measuring the distance between the centers of the two virtual rolling rod circles.

[0039] The present invention has the following beneficial effects:

[0040] The present invention realizes spatial scanning and data point collection of the tenon morphology contour through a four-axis coordinate device and a confocal spectral sensor, can perform non-contact detection of the tenon morphology contour, and obtain the actual contour of the tenon morphology contour, with higher detection efficiency. At the same time, it will not cause damage to the tenon surface, and can achieve high-precision and high-efficiency detection of the tenon morphology contour, which makes up for the shortcomings of current tenon measurement such as manual operation, low precision, and inability to digitize, and can simultaneously meet the detection requirements of large size curvature, high precision, and complex evaluation parameters of the tenon of aero-engine blades.

[0041] In addition to the above-described purposes, features and advantages, the present invention has other purposes, features and advantages. The present invention will be further described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0043] Figure 1 This is the process drawing of a certain type of turbine blade tenon.

[0044] Figure 2 The present invention is a flow chart of the non-contact detection method for the tenon profile of aero-engine turbine blades.

[0045] Figure 3 This is a schematic diagram of the tenon tolerance zone curve.

[0046] Figure 4 Schematic diagram of the tenon theory data set.

[0047] Figure 5 A schematic diagram is established for the tenon coordinate system in step S3.

[0048] Figure 6 Schematic diagram of theoretical contour separation.

[0049] Figure 7 This is a schematic diagram of the error of conventional means for evaluating tenon pitch.

[0050] Figure 8 This is a schematic diagram of the error of conventional means for evaluating tenon pitch.

[0051] Fig. 9 Schematic diagram for virtual roller circle in tenon pitch evaluation.

[0052] Fig.10 A schematic diagram is established for the evaluation coordinate system in the tenon pitch evaluation.

[0053] Fig.11 A schematic diagram is established for the evaluation coordinate system in the tenon pitch evaluation. DETAILED DESCRIPTION

[0054] The embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0055] See also Figure 1-11 The present invention provides a technical solution: a tenon profile detection method, using a 4-axis coordinate device and a confocal spectrum sensor to achieve tenon profile scanning and acquisition and non-contact optical detection of spatial points, including the following steps:

[0056] S1, confocal spectral sensor focus error compensation and indication error compensation;

[0057] Due to the high processing precision of the tenon profile, the confocal spectral sensor needs to compensate for the focal length error and indication error;

[0058] S2, converting the theoretical data of the tenon morphology profile into a theoretical data set of the tenon morphology profile;

[0059] like Figure 3 As shown, the theoretical data of the tenon profile include the theoretical profile and the tolerance band curve;

[0060] like Figure 4 As shown, the theoretical data set includes the theoretical values, upper tolerance and lower tolerance data of points on the theoretical contour;

[0061] S3, refer to the aviation blade tenon coordinate system establishment specification, establish the tenon coordinate system, this coordinate system is used as the three-dimensional spatial positioning basis for confocal spectroscopy detection;

[0062] S4, after the optical parameters of the confocal spectral sensor are adjusted, a non-contact optical scanning of the tenon profile is performed to obtain the actual profile of the tenon;

[0063] According to the size, position and curvature of the tenon, determine the appropriate scanning speed, acceleration and point density, probe angle, turntable angle, optical tracking, optical frequency, light intensity, filtering and other parameters to ensure measurement efficiency and accuracy.

[0064] The above method can be used to perform non-contact detection of the tenon profile and obtain the actual contour of the tenon profile, which has higher detection efficiency and will not cause damage to the tenon surface. High-precision and high-efficiency detection of the tenon profile can be achieved, which makes up for the current shortcomings of manual operation, low precision and inability to digitize the tenon measurement. It can also meet the detection requirements of large size curvature, high precision and complex evaluation parameters of the tenon of aero-engine blades.

[0065] Specifically, as shown in the figure, in step S1, the focal error compensation needs to use a matte white ceramic ball as a standard to ensure the quality of light reflection. The spiral line is scanned in the ±30° area of ​​the spherical crown, with a total of 5 layers, using a point density of 0.1mm / point and a scanning speed of 10mm / second. The scanning point set uses a fixed sphere diameter algorithm to fit and iteratively calculate the sphere center coordinates to calibrate the focal error of the sensor. Three measurement steps are performed continuously at the three positions of the sensor range of -80%, 0%, and +80%, and the average of the three measurement steps is calculated to complete the calibration compensation of the sensor.

[0066] Specifically, as shown in the figure, in step S1, the method for compensating the indication error of the confocal spectral sensor is to use a step gauge or a standard instrument flat crystal and a gauge block combination to build a standard step difference model, use the confocal spectral sensor to detect the standard step height, evaluate the sensor measurement error, and use the step gauge or flat crystal reference plane of the standard instrument reference system to establish the first reference of the coordinate system, establish the Z axis, and measure 4 points; use the step gauge or the side of the flat crystal to establish the second reference of the coordinate system, establish the X axis, and measure 2 to 3 points; use the step gauge or the flat crystal third plane to establish the X origin; measure the distance from the step cabinet or the gauge block surface to the Z plane of the reference system, and compare it with the agreed true value of the standard instrument to obtain the error compensation measurement value.

[0067] Specifically, in step S2, since the tolerance zone of the tenon morphology profile is a variable tolerance curve, it is very difficult to draw and define manually, and it is easy to produce a problem of uneven transition area, resulting in curve error. In order to improve accuracy and efficiency, a drawing software can be used to draw a theoretical profile and tolerance zone and import it into the tenon analysis software to mirror out a graphic consistent with the design;

[0068] Specifically, in step S2, when the theoretical data of the tenon profile does not contain a complete tolerance band curve, it is necessary to obtain a complete tolerance band curve through tolerance continuous change transition calculation. The tolerance value of each two adjacent points in the transition area is equal to the ratio of the point distance to the tolerance difference. The specific calculation method is expressed as:

[0069]

[0070] Where: x1, x2, y1, y2 represent the X and Y coordinates of each adjacent point, δs represents the distance between two adjacent points, S represents the total distance of all points in the transition area, LT1, LT2 represent the original tolerance values ​​of the transition area points, and LT' represents the calculated transition tolerance value.

[0071] The "not including the complete tolerance zone curve" mentioned here means that there is no tolerance zone curve in the area other than the working surface and the arc area. The working surface and the arc area have tolerance zone curves on the design drawing. The above method is how to calculate the tolerance zone of the transition area between the working surface and the arc area.

[0072] Specifically, in step S2, if Figure 4 As shown, when the theoretical data of the tenon profile includes a complete tolerance zone curve, each point in the theoretical profile is projected to the upper and lower tolerance zones in the vector direction, the intersection points are calculated one by one, and the distance is calculated to define the tolerance value, and the data is summarized into a theoretical data set with tolerances in a unified format of X, Y, Z, I, J, K, UT, and LT;

[0073] Among them, X, Y, and Z represent the coordinates of the point, I, J, and K represent the vector of the point, UT represents the upper tolerance, and LT represents the lower tolerance.

[0074] Specifically, in step S3, when establishing the coordinate system of the tenon, refer to the aviation blade tenon coordinate system establishment specification, use a physical roller to contact the blade working surface, and complete the coordinate system establishment after obtaining the roller contact point. This method is used in the calculation of bearing raceways and gear spans, such as Figure 5 As shown, in order to improve the detection efficiency, a contact probe with a diameter equal to the roller diameter is used. The specific method for establishing the coordinate system of the tenon is as follows:

[0075] S31, find the center position of the probe on the tenon through three-dimensional simulation centering perception in the direction of the front edge and the rear edge of the tenon, and calculate the coordinates of the roller contact point through trigonometric function relationship. As shown in the figure, there are 4 points in total, represented by L1, L2, R1, R2, and the measuring point X1 of the end face of the tenon rear edge is X1, which is the reference point specified on the tenon process drawing;

[0076] S32, use the four contact points of the tenon L1, L2, R1, and R2 to calculate the axis of the plane in which they are located, with the orientation being the blade stacking axis and the direction being pointing to the blade tip, and establish the origin of the Z axis;

[0077] S33, using the connecting line of L1 and L2 and the connecting line of R1 and R2 to calculate the midline to establish the axis, the direction is toward the trailing edge of the blade, and the origin of the Y axis is established;

[0078] S34, use point X1 to establish the X origin.

[0079] The purpose of establishing the tenon coordinates is to ensure that when a non-contact method is used to detect the tenon profile, the non-contact sensor carried by the detection device needs to accurately reach the location of the tenon scanning section.

[0080] Specifically, because the surface of the blade tenon is bright after high-precision shaping and grinding, the confocal spectral sensor has the ability to detect bright surfaces, but it also requires fine adjustment of optical parameters to achieve this. Before starting the scanning task, when the white light is focused on the surface of the part, the exposure time is automatically adjusted to make the monitoring light intensity signal between 15% and 40%, achieving the best;

[0081] Further, in step S4, if Figure 6 As shown, when the tenon profile is non-contact optically scanned, the tenon profile is symmetrically divided into two parts in the tenon width direction to facilitate scanning by a 4-axis coordinate (XYZR) device.

[0082] At present, when evaluating the contour of turbine blade tenons, the method mainly relies on the use of standard magnified images, and uses large vertical projectors for contour comparison and qualitative detection. The magnified images are printed by magnifying the tenon contour and tolerance band by 25 to 50 times using materials such as polyester film. The tenon contour and the magnified image are manually projected and magnified under the same light source system. This method has the problems of long manual debugging cycle, large error in magnified image printing, low detection efficiency, poor repeatability, inability to obtain detection values ​​such as contour, misalignment, pitch, and inability to digitize.

[0083] Therefore, a method for evaluating the tenon profile of an aircraft engine turbine blade is proposed, which is applicable to the above-mentioned non-contact detection method of the tenon profile of an aircraft engine turbine blade. The actual tenon profile is imported into the tenon profile analysis software to perform profile analysis, including the following steps:

[0084] S51, dividing the actual contour of the tenon topography into two parts: an overall contour and a working surface contour;

[0085] S52, using Gaussian least squares method to calculate the deviation and perform fitting processing on the overall profile obtained in step S51 to obtain an overall best fitting curve;

[0086] S53, using the working surface profile obtained in step S51 to calculate the deviation and fit again using the quadratic Gaussian least squares method based on the overall best fitting curve, to obtain the working surface best fitting curve, and comparing the working surface best fitting curve with the tolerance band curve and the theoretical profile to evaluate the tenon profile;

[0087] The general expression is as follows:

[0088]

[0089] Where:

[0090] θ is the optimal fitting parameter

[0091] S is the residual sum of squares

[0092] x i ,y i For data points

[0093] This method uses the working surface as the tenon contour weight set, performs the best fitting of the tolerance band under the weight mode for the actual morphological contour of the entire tenon, and obtains the contour analysis data. Since the tenon of an aircraft engine turbine blade is a typical variable tolerance band contour assessment, the tolerance of the working surface is usually very small and the tolerance of the arc part is usually large. According to the actual assembly needs of the blade tenon on the aircraft engine turbine disk, the tenon working surface is the key part of the entire tenon. During the evaluation process, it is necessary to first ensure that the contour points of the working surface are within the tolerance band (when the working surface contour is out of tolerance, a high-level weighted fitting is required to prioritize ensuring that the most points enter the tolerance band), and then determine whether the remaining contours (mainly the arc transition part) are within the tolerance band, so as to finally meet the technical requirements for tenon contour fitting.

[0094] The working surface of the tenon of the aircraft engine turbine blade is very short, and the tolerance requirements are extremely strict. Generally, the tolerance requirements are at the micron level. There are two conventional methods, such as Figure 7 As shown in the figure, one is to directly evaluate the distance between the two working surfaces (lines). When the vertical distance is directly calculated, due to the short working surface, a small detection error will cause the error to be extended and amplified, such as Figure 8 As shown in the figure, it is a method to calculate the projection by referring to the center line of the centering circle of the single span rod as the reference of the coordinate system. Since the working surface is single-sided, the centering circle needs to be calculated using the opposite surface, which will cause the problem of asymmetric contact points of the centering circles on both sides;

[0095] Therefore, a method for evaluating the pitch of the tenon of an aero-engine turbine blade is proposed, which is applicable to the non-contact detection method of the tenon profile of the aero-engine turbine blade, and includes the following steps:

[0096] S61, such as Fig. 9As shown, the actual morphology profile of the tenon obtained in step S4 is imported into the tenon analysis software to establish two sets of virtual roller circles, and the diameter of the virtual roller circle is the theoretical roller diameter required by the technology;

[0097] S62, such as Fig.10 As shown, the virtual roller circle is positioned to the real roller position in the actual topographic profile of the tenon, and the first group of roller lower contact points L1, R1 and the second group of roller upper contact points L2, R2 are obtained;

[0098] The two virtual roller circles of the same group are respectively set on both sides of the actual topographic contour of the tenon. The virtual roller circles are in contact with the two upper and lower adjacent working surfaces at the same time to obtain the real roller position.

[0099] S63, such as Fig.10 As shown, the center line LINE1 and the midpoint O1 of the first group of rollers, the center line LINE2 and the midpoint O2 of the second group of rollers are calculated respectively, and the fitting line LINE3 of LINE1 and LINE2, and the midpoint O3 of O1 and O2 are calculated;

[0100] S64, such as Fig.11 As shown, a two-dimensional pitch evaluation coordinate system is established with LINE3 as the X-axis and 03 as the origin of X and Y;

[0101] S65, such as Fig.11 As shown, the tooth pitch evaluation coordinate system is rotated by the process angle α according to the requirements on the tenon process drawing, and the left tooth distance LC and the right tooth distance RC are evaluated respectively.

[0102] like Figure 1 This is the process drawing of a certain type of turbine blade tenon. Figure 1 It can be seen that the theoretical roller diameter is 2.7 mm and the process angle α is 50°.

[0103] This method uses the centerline fitting method of two groups of virtual roller circles as the baseline method to calculate the tooth pitch. This method fits the upper and lower groups of virtual roller circle positions and calculates the tooth pitch in the fitting coordinate system. This method fully considers the problem of inconsistent processing status of different groups of roller positions, and achieves good repeatability of small tooth pitch calculation and good symmetry of calculation results.

[0104] The span is the distance between the centers of the rollers. The traditional measurement method is to make two physical rollers with very high precision, manually hold the two rollers on the tenon, and then use a measuring tool such as a micrometer to measure. It cannot be digitized and is also affected by manual measurement, with poor repeatability and unreliable measurement.

[0105] Therefore, a method for evaluating the span of tenons of turbine blades of aircraft engines is proposed, which is applicable to the non-contact detection method of the tenon profile of turbine blades of aircraft engines, and includes the following steps:

[0106] S71, importing the actual topography profile of the tenon obtained in step S4 into the tenon analysis software, and establishing two virtual roller circles, the diameter of the virtual roller circle being the theoretical roller diameter required by the technology;

[0107] S72, positioning the virtual roller circle to the real roller position in the actual topographic profile of the tenon;

[0108] S73, measuring the distance between the centers of the two virtual rolling rod circles.

[0109] The method adopts a virtual rolling rod circle to replace the traditional physical rolling rod, making the measurement of the tenon span distance more simple, convenient and accurate.

[0110] When positioning the virtual roller circle to the real roller position, the following four modes can be used:

[0111] 1. Point mode: small amount of calculation, fast speed, can quickly virtualize the bottom circle tangent to the curve. This algorithm is sensitive to point density and quality, and has low repeatability. It is suitable for curve data types with high point density.

[0112] 2. Cubic spline interpolation mode: The amount of calculation increases, but the algorithm is simple and easy to program. The curve is decomposed into individual line segments to calculate the tangent circle. To a certain extent, it avoids the curve data type with high point density and can achieve a certain accuracy.

[0113] 3. Linear interpolation (linear spline) mode: Generate B-spline curves from curve points, and calculate the lowest circle by tangent between the curve and the circle. It has high repeatability and accuracy and is suitable for curves with uniform point density.

[0114] 4. Segmented cubic interpolation (Akima spline) mode: a curve interpolation method that takes into account the slope and curvature of the curve. It is better than the cubic algorithm under conditions of non-uniform point density. In the invention, considering that the optical scanning data exhibits non-uniform point density, the use of the Akima algorithm has advantages.

[0115] Since different confocal spectral sensors have different capabilities, the point density of the actual morphological contour of the tenon measured by them is different. The above four different calculation methods can be selected according to the actual situation.

[0116] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A tenon profile detection method, using a 4-axis coordinate device and a confocal spectrum sensor to achieve tenon profile scanning and acquisition and non-contact optical detection of spatial points, characterized in that: The following steps are involved: S1, confocal spectral sensor focus error compensation and indication error compensation; S2, converting the theoretical data of the tenon morphology profile into a theoretical data set of the tenon morphology profile; The theoretical data of tenon profile include theoretical profile and tolerance band curve; The theoretical data set includes the theoretical values, upper tolerance and lower tolerance data of points on the theoretical contour; S3, refer to the specification for establishing the coordinate system of the tenon of an aviation blade to establish the coordinate system of the tenon; S4, after the optical parameters of the confocal spectral sensor are adjusted, a non-contact optical scan of the tenon profile is performed to obtain the actual tenon profile.

2. The tenon profile detection method according to claim 1, characterized in that: In step S2, when the theoretical data of the tenon profile does not contain a complete tolerance band curve, it is necessary to obtain a complete tolerance band curve through tolerance continuous change transition calculation. The specific calculation method is expressed as follows: Where: x1, x2, y1, y2 represent the X and Y coordinates of each adjacent point, δs represents the distance between two adjacent points, S represents the total distance of all points in the transition area, LT1, LT2 represent the original tolerance values ​​of the transition area points, and LT' represents the calculated transition tolerance value.

3. The tenon profile detection method according to claim 1, characterized in that: In step S2, by projecting each point in the theoretical profile to the upper and lower tolerance zones in the vector direction, calculating the intersection points one by one and calculating the distance to define the tolerance value, the data is summarized into a theoretical data set with tolerance in a unified format of X, Y, Z, I, J, K, UT, and LT; Among them, X, Y, and Z represent the coordinates of the point, I, J, and K represent the vector of the point, UT represents the upper tolerance, and LT represents the lower tolerance.

4. The tenon profile detection method according to claim 1, characterized in that: In step S3, when establishing the coordinate system of the tenon, a contact probe having a diameter equal to the diameter of the roller is used. The specific method for establishing the coordinate system of the tenon is as follows: S31, find the center position of the probe on the tenon through three-dimensional simulation centering perception in the direction of the front edge and the rear edge of the tenon, and calculate the coordinates of the roller contact point through trigonometric function relationship. There are 4 points in total, which are represented as L1, L2, R1, R2, and the measuring point X1 of the end face of the tenon rear edge; S32, use the four contact points of the tenon L1, L2, R1, and R2 to calculate the axis of the plane in which they are located, with the orientation being the blade stacking axis and the direction being pointing to the blade tip, and establish the origin of the Z axis; S33, using the connecting line of L1 and L2 and the connecting line of R1 and R2 to calculate the midline to establish the axis, the direction is toward the trailing edge of the blade, and the origin of the Y axis is established; S34, use point X1 to establish the X origin.

5. The tenon profile detection method according to claim 1, characterized in that: In step S4, when the tenon profile is non-contact optically scanned, the tenon profile is symmetrically divided into two parts in the tenon width direction.

6. A method for evaluating the tenon profile of an aircraft engine turbine blade, applicable to the tenon profile detection method according to claim 1, characterized in that: The following steps are involved: S51, dividing the actual contour and theoretical contour of the tenon profile into two parts: an overall contour and a working surface contour; S52, using Gaussian least squares method to calculate the deviation and perform fitting processing on the overall profile obtained in step S51 to obtain an overall best fitting curve; S53, based on the overall best fitting curve, the working surface contour obtained in step S51 is used to calculate the deviation and fitting processing again using the quadratic Gaussian least squares method to obtain the best fitting curve of the working surface, and the best fitting curve of the working surface is compared with the tolerance band curve and the theoretical contour to evaluate the tenon contour.

7. A method for evaluating the pitch of a tenon of an aircraft engine turbine blade, applicable to the tenon profile detection method according to claim 1, characterized in that: The following steps are involved: S61, importing the actual topography profile of the tenon obtained in step S4 into the tenon analysis software, and establishing two sets of virtual roller circles, where the diameter of the roller is the theoretical roller diameter required by the technology; S62, positioning the virtual roller circle to the real roller position in the actual topographic profile of the tenon, and obtaining the first group of roller lower contact points L1, R1 and the second group of roller upper contact points L2, R2; S63, respectively calculating the center line LINE1 and the midpoint O1 of the first group of rollers, the center line LINE2 and the midpoint O2 of the second group of rollers, and calculating the fitting line LINE3 of LINE1 and LINE2, and the midpoint O3 of O1 and O2; S64, establish a two-dimensional pitch evaluation coordinate system with LINE3 as the X axis and 03 as the origin of X and Y; S65, rotating the tooth pitch evaluation coordinate system by the process angle α according to the requirements on the tenon process drawing, and evaluating the left tooth distance LC and the right tooth distance RC respectively.

8. A method for evaluating the span of tenons of turbine blades of aircraft engines, applicable to the tenon profile detection method of claim 1, characterized in that: The following steps are involved: S71, importing the actual topography profile of the tenon obtained in step S4 into the tenon analysis software, establishing two virtual roller circles, and the diameter of the roller is the theoretical roller diameter required by the technology; S72, positioning the virtual roller circle to the real roller position in the actual topographic profile of the tenon; S73, measuring the distance between the centers of the two virtual rolling rod circles.

Images