Three-coordinate detection and evaluation method for mortise of fir-tree-shaped turbine disc of gas turbine

Abstract

The invention provides a three-coordinate detection and evaluation method for a mortise of a fir-tree-shaped turbine disc of a gas turbine, and the method comprises the following steps: S1, placing the turbine disc on a three-coordinate detection platform, and keeping the position of a first groove of the turbine disc in the Y-axis direction of a three-coordinate machine tool; s2, importing a digital model, acquiring two points of two opposite working surfaces of a wheel disc reference surface, a reference circle and a first groove by a three-coordinate probe according to drawing requirements, and establishing a coordinate system; s3, deconstructing each size element required to be measured for the mortise; and S4, collecting geometrical characteristics in the mortise in a three-coordinate manner, constructing corresponding size elements for evaluation, judging whether the requirements of a drawing are met or not according to a preset tolerance threshold value, and completing detection. The method can be suitable for various types of gas compressor dovetail type mortises and turbine fir tree type mortises of other sizes, a complex inspection method of an auxiliary measuring tool is converted into a simple, efficient and good-universality geometric feature structure detection method, manual detection time and research and development design cost are saved, and accuracy is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of fir-tree type turbine disk tenon and groove detection, and in particular relates to a three-coordinate detection and evaluation method for a fir-tree type turbine disk tenon and groove of a gas turbine. Background Art

[0002] The impeller is a key part of the marine gas turbine, and the tenon and groove of the impeller is the interface for installing the gas turbine blades. The size of the tenon and groove is more important and is a key characteristic of the gas turbine. The processing quality of the tenon and groove of the impeller directly affects the performance of the gas turbine. Therefore, the inspection of the tenon and groove of the impeller is an effective way to ensure the performance of the engine rotor product.

[0003] During operation, the wheel rotates at high speed, driving the blades installed on the outer circular tenon of the wheel to perform work with compressed air. The assembly of the wheel tenon and blade is of utmost importance. The tenon of the wheel and the tenon of the blade are assembled by plug-in. The wheel tenon has a complex structure, mostly dovetail and fir-tree type tenons. It is difficult to process and has high dimensional accuracy. It has always been a key difficulty in manufacturing and testing.

[0004] At present, there are two common methods for detecting the fir-tree-shaped tenon groove of turbine disks. One method is to use a special tenon groove measuring tool for measurement, which requires the processing accuracy of the tenon groove measuring tool to be higher than the accuracy of the wheel tenon groove. Different types of fir-tree-shaped tenons require the design of different special measuring tools. The manufacturing cost of the measuring tool is high and the manufacturing cycle is long. In addition, there are cumulative errors when the tenon groove is detected manually using the measuring tool, which is inefficient, and the repeatability of the measurement results is poor, and the measurement results are inaccurate. The second method is to use the wheel locating hole or locating groove to establish a coordinate system in three-coordinate measurement. This method is currently a common method for three-coordinate detection of tenons and grooves. It requires high accuracy of the locating hole and groove, and ensures that there is no wear on the inner surface of the hole during the broaching process. In fact, in the process of heavy wheel broaching and hoisting, wear on the inner surface of the hole is inevitable. Using the locating hole and groove for coordinate system positioning will cause errors in the measurement results, affecting the judgment of the authenticity of the results. Summary of the invention

[0005] The purpose of the present invention is to provide a three-coordinate detection and evaluation method for the tenon groove of a fir-tree-type turbine disk of a gas turbine, which can be independent of the assistance of special measuring tools and other positioning holes and grooves, and can efficiently and accurately complete the rapid detection of the tenon groove.

[0006] A three-coordinate detection and evaluation method for a gas turbine fir-tree-shaped turbine disk tenon groove comprises the following steps:

[0007] S1, placing the turbine disc on the three-coordinate inspection platform, with the first slot position kept in the Y-axis direction of the three-coordinate machine tool;

[0008] S2, import the digital model, and according to the drawing requirements, use the three-coordinate probe to collect two points on the wheel reference surface, reference circle and two opposite working surfaces of the first slot to establish a coordinate system;

[0009] S3, deconstruct the various dimensional elements that need to be measured for the mortise and tenon;

[0010] S4, the three-coordinate system collects the geometric features in the mortise and tenon, constructs the corresponding dimensional elements for evaluation, and determines whether it meets the drawing requirements based on the preset tolerance threshold, and completes the inspection.

[0011] Furthermore, the S2 specifically includes the following steps:

[0012] S2-1, evenly collect three points on the datum plane of the digital model of the wheel, evenly collect three points on the datum outer circle of the digital model of the wheel, construct the outer circle with three points, select one point from each of the left and right working surfaces in the mortise and tenon groove, and construct the midpoint with two points;

[0013] S2-2, align the three points of the reference plane, rotate the outer circle to the midpoint, use the outer circle as the center of the coordinate system, use the iteration method to initially build the coordinate system, the reference plane is the coordinate system Z zero, the Z positive axis is perpendicular to the reference plane, and the outer circle is the origin of the coordinate system X and Y axes;

[0014] S2-3, repeat the above two steps, in this step, the number of iterations of the iterative method is changed to 99 times, the tolerance is changed to the minimum tolerance of the drawing, and points are taken on the wheel to measure all the above features, and the above geometric features are continuously iterated until the iterative error between the actual part and the digital model meets the requirements;

[0015] S2-4, select a sampling point at any position of the wheel to verify whether the X, Y, Z and vector direction of the sampling point and the digital-analog deviation value T meet the minimum tolerance.

[0016] Furthermore, the dimensional elements that need to be measured in S3 include:

[0017] S3-1, mortise angle α: the inclination angle of the mortise relative to the axis of the wheel disc;

[0018] S3-2, mortise and tenon N value: the positioning dimension of the mortise and tenon along the circumference of the wheel disc;

[0019] S3-3, tenon groove P point: blade tenon root positioning point;

[0020] S3-4, mortise center distance A1: the distance between the mortise point P and the center of the rotation axis in the straight line direction of the wheel disc;

[0021] S3-5, mortise center distance A2: the distance between mortise point P and the bottom surface of the mortise;

[0022] S3-6, mortise center distance U: the distance between the mortise point P and the outer circle of the wheel base;

[0023] S3-7, inclination Q1: the deflection distance of the mortise and tenon working surface from the center axis 100;

[0024] S3-8, inclination Q2: the deviation 100 distance between the symmetry plane of the mortise and tenon and the radial plane;

[0025] S3-9, mortise and tenon uniform distribution T1: position degree of each mortise and tenon.

[0026] Furthermore, the inclination Q1 is the inclination of the left evaluation line LL and the left working surface SL of the digital model tenon groove in the projection length of 100 mm and the inclination of the right evaluation line RR and the right working surface SR of the digital model tenon groove in the projection length of 100 mm.

[0027] Further, the inclination Q2 detection method 1: evaluate the inclination of the straight line FM and the dividing surface M1 in the digital model at a projection length of 100 mm;

[0028] Detection method 2: evaluate the 3D distance between point P2 and plane F;

[0029] Test method 3: Evaluate the 3D angle β between the measured midplane M and the midplane M1 in the digital model;

[0030] Use three coordinates to assign / V=TAN(β*π / 180)*100.

[0031] Furthermore, the S4 specifically includes the following steps:

[0032] S4-1, use a three-coordinate probe to collect points or scan a pair of working surfaces of the part's mortise and tenon groove to construct the left side L and the right side R;

[0033] S4-2, construct the measured median plane M of the left side L and the right side R;

[0034] S4-3, offset the measured midplane M by the theoretical distance A4 in the vector direction, and construct the offset left plane L1 and the offset right plane R1;

[0035] S4-4, offset the left surface L1 and the left surface L to construct the left straight line LL, offset the right surface R1 and the right surface R to construct the right straight line RR;

[0036] S4-5, measure the part reference surface B, measure the part reference outer circle C, offset the part reference surface B by a theoretical distance A5 in the negative direction of the Z axis, and construct the offset reference surface B1;

[0037] S4-6, construct a plane F perpendicular to the Y axis of the coordinate system;

[0038] S4-7, bottom surface D of the structural part mortise and tenon groove;

[0039] S4-8, construct the intersection line FM of plane F and measured median plane M, the line FM pierces the bottom surface D of the mortise groove, and constructs point D1;

[0040] S4-9, projecting the part reference outer circle C onto the offset reference plane B1 to construct a projection circle C1;

[0041] S4-10, the center of the projected circle C1 and the point P construct a straight line PC1, the straight line PC1 pierces the projected circle C1, and a point P1 is constructed;

[0042] S4-11, collect the digital model of the left working surface SL and the right working surface SR of the tenon groove; the digital model dividing surface M1 of the construction surface SL and the surface SR;

[0043] S4-11, construct a straight line 1 that is 100 mm away from point P in the positive direction of the X axis and whose vector direction is the Y axis;

[0044] S4-12, straight line 1 pierces the measured construction point P2 of the midpoint M.

[0045] The beneficial effects of the present invention are as follows: the present invention uses an iterative method to establish a coordinate system, the part coordinate system is continuously iterated with the digital model coordinate system to the drawing accuracy, and for the mortise and tenon that needs to be detected, the turbine disc mortise and tenon are deconstructed in the coordinate system, and then converted into measurement values ​​of various dimensional elements, and then compared with the tolerance threshold of the mortise and tenon in the drawing, it can be judged whether the position size of the mortise and tenon is qualified; the method can be applied to various types of compressor dovetail mortise and tenon and other sizes of turbine fir-tree mortise and tenon, and by converting the complex inspection method of auxiliary measuring tools into a simple, efficient and versatile inspection method of geometric feature structure, it saves manual inspection time and R&D design costs and improves accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 This is a schematic diagram of the digital model of the roulette wheel of the present invention;

[0047] Figure 2 A is a schematic diagram of the inspection of the mortise and tenon groove of the wheel according to the present invention;

[0048] Figure 3 Schematic diagram B of the inspection of the mortise and tenon groove of the wheel of the present invention;

[0049] Figure 4 Schematic diagram C of the inspection of the mortise and tenon groove of the wheel according to the present invention;

[0050] Figure 5 This is a schematic diagram D of the inspection of the mortise and tenon groove of the wheel according to the present invention;

[0051] Figure 6 Schematic diagram E of the inspection of the mortise and tenon groove of the wheel according to the present invention;

[0052] Figure 7 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0053] The present invention is further described below in conjunction with the accompanying drawings.

[0054] like Figure 1-Figure 7 As shown, a three-coordinate detection and evaluation method for the tenon groove of a fir-tree-shaped turbine disk of a gas turbine comprises the following steps:

[0055] S1, placing the turbine disc on the three-coordinate inspection platform, with the first slot position kept in the Y-axis direction of the three-coordinate machine tool;

[0056] S2, import the digital model, and according to the drawing requirements, use the three-coordinate probe to collect two points on the wheel reference surface, reference circle and two opposite working surfaces of the first slot to establish a coordinate system;

[0057] S2-1, evenly collect three points on the datum plane of the digital model of the wheel, evenly collect three points on the datum outer circle of the digital model of the wheel, construct the outer circle with three points, select one point from each of the left and right working surfaces in the mortise and tenon groove, and construct the midpoint with two points;

[0058] S2-2, align the three points of the reference plane, rotate the outer circle to the midpoint, use the outer circle as the center of the coordinate system, use the iteration method to initially build the coordinate system, the reference plane is the coordinate system Z zero, the Z positive axis is perpendicular to the reference plane, and the outer circle is the origin of the coordinate system X and Y axes;

[0059] S2-3, repeat the above two steps, in this step, the number of iterations of the iterative method is changed to 99 times, the tolerance is changed to the minimum tolerance of the drawing, and points are taken on the wheel to measure all the above features, and the above geometric features are continuously iterated until the iterative error between the actual part and the digital model meets the requirements;

[0060] S2-4, select a sampling point at any position of the wheel, and verify whether the X, Y, Z and vector direction of the sampling point and the digital-analog deviation value T meet the minimum tolerance;

[0061] S3, deconstruct the various dimensional elements that need to be measured for the mortise and tenon;

[0062] S3-1, mortise angle α: the inclination angle of the mortise relative to the axis of the wheel disc;

[0063] Detection method: evaluate the 3D angle between the measured plane M and the Z axis;

[0064] S3-2, mortise and tenon N value: the positioning dimension of the mortise and tenon along the circumference of the wheel disc;

[0065] Detection method: 3D distance between evaluation point D1 and reference surface B;

[0066] S3-3, tenon groove P point: blade tenon root positioning point;

[0067] Detection method: the evaluation line LL and the line RR pierce the offset reference plane B1 respectively, constructing points DL and DR, points DL and DR construct the line LR, the line LR pierces the measured median plane M, and constructs point P;

[0068] S3-4, mortise center distance A1: the distance between the mortise point P and the center of the rotation axis in the straight line direction of the wheel disc;

[0069] Detection method: 2D distance between evaluation point P and the center of the reference outer circle;

[0070] S3-5, mortise center distance A2: the distance between mortise point P and the bottom surface of the mortise;

[0071] Detection method: 2D distance between evaluation point P and bottom surface D of mortise and tenon groove;

[0072] S3-6, mortise center distance U: the distance between the mortise point P and the outer circle of the wheel base;

[0073] Detection method: evaluate the 2D distance between point P and point P1 parallel to the X-axis;

[0074] S3-7, inclination Q1: the deflection of the mortise and tenon working surface from the center axis;

[0075] Testing method: evaluate the inclination of the left straight line LL and the left working surface SL of the digital mold tenon groove at a projection length of 100mm; evaluate the inclination of the right straight line RR and the right working surface SR of the digital mold tenon groove at a projection length of 100mm;

[0076] S3-8, inclination Q2: the deviation 100 distance between the symmetry plane of the mortise and tenon and the radial plane;

[0077] Test method 1: Evaluate the inclination of the straight line FM and the dividing surface M1 in the digital model at a projection length of 100 mm;

[0078] Detection method 2: 3D distance between evaluation point P2 and plane F

[0079] Test method 3: Evaluate the 3D angle β between the measured midplane M and the midplane M1 in the digital model.

[0080] Use three coordinates for assignment / V = ​​TAN (β * π / 180) * 100;

[0081] S3-9, mortise and tenon uniform distribution T1: position of each mortise and tenon;

[0082] Detection method: Select any point on the working surface of a mortise and tenon on the digital model, select the array function in the three-coordinate system, array the same point at the same position of all mortise and tenon on the digital model, and automatically collect the points arrayed on the digital model on the part, and evaluate the deviation T1 between the measured point and the theoretical point of the digital model;

[0083] The inclination Q1 is the inclination of the left evaluation line LL and the left working surface SL of the digital mold tenon groove at a projection length of 100 mm and the inclination of the right evaluation line RR and the right working surface SR of the digital mold tenon groove at a projection length of 100 mm;

[0084] The inclination Q2 detection method 1: evaluate the inclination of the straight line FM and the dividing surface M1 in the digital model at a projection length of 100 mm;

[0085] Detection method 2: evaluate the 3D distance between point P2 and plane F;

[0086] Test method 3: Evaluate the 3D angle β between the measured midplane M and the midplane M1 in the digital model;

[0087] Use three coordinates to assign / V=TAN(β*π / 180)*100.

[0088] S4, the three-coordinate system collects the geometric features in the mortise and tenon, constructs the corresponding dimensional elements for evaluation, and determines whether it meets the drawing requirements based on the preset tolerance threshold, and completes the inspection.

[0089] S4-1, use a three-coordinate probe to collect points or scan a pair of working surfaces of the part's mortise and tenon groove to construct the left side L and the right side R;

[0090] S4-2, construct the measured median plane M of the left side L and the right side R;

[0091] S4-3, offset the measured midplane M by the theoretical distance A4 in the vector direction, and construct the offset left plane L1 and the offset right plane R1;

[0092] S4-4, offset the left surface L1 and the left surface L to construct the left straight line LL, offset the right surface R1 and the right surface R to construct the right straight line RR;

[0093] S4-5, measure the part reference surface B, measure the part reference outer circle C, offset the part reference surface B by a theoretical distance A5 in the negative direction of the Z axis, and construct the offset reference surface B1;

[0094] S4-6, construct a plane F perpendicular to the Y axis of the coordinate system;

[0095] S4-7, bottom surface D of the structural part mortise and tenon groove;

[0096] S4-8, construct the intersection line FM of plane F and measured median plane M, the line FM pierces the bottom surface D of the mortise groove, and constructs point D1;

[0097] S4-9, projecting the part reference outer circle C onto the offset reference plane B1 to construct a projection circle C1;

[0098] S4-10, the center of the projected circle C1 and the point P construct a straight line PC1, the straight line PC1 pierces the projected circle C1, and a point P1 is constructed;

[0099] S4-11, collect the digital model of the left working surface SL and the right working surface SR of the tenon groove; the digital model dividing surface M1 of the construction surface SL and the surface SR;

[0100] S4-11, construct a straight line 1 that is 100 mm away from point P in the positive direction of the X axis and whose vector direction is the Y axis;

[0101] S4-12, straight line 1 pierces the measured construction point P2 of the midpoint M.

[0102] The present invention is aimed at the inspection of the tenon of a fir-tree-type turbine disc of a gas turbine, and specifically mainly includes the measurement of key elements such as the tenon angle α, the tenon N value, the tenon P point, the tenon center distance A1, the tenon center distance A2, the tenon center distance U, the inclination Q1, the inclination Q2, the tenon uniform distribution T1 position and the like.

[0103] The above measurement dimensions have a great impact on the use of turbine blades during operation. The mortise angle α is the angular direction of the blade after the turbine blade is assembled, which is used to ensure that the air flow path can work according to the design requirements; the mortise N value can ensure that the position of the turbine blade installed on the mortise meets the design requirements when the turbine blade is installed in the mortise; the mortise P point, mortise center distance A1, mortise center distance A2, and mortise center distance U are mainly used to control the tip diameter of the turbine blade after the turbine blade is assembled, so that the air flow rate works according to the design drawings and ensures the output of the gas turbine power; the inclination Q1, inclination Q2, and mortise uniform distribution T1 position are used to evaluate the groove type of the mortise to ensure that the mating surface of the turbine blade and the mortise assembly meets the design drawings.

[0104] 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 three-coordinate detection and evaluation method for the tenon groove of a fir-tree-shaped turbine disk of a gas turbine, characterized in that: The following steps are involved: S1, placing the turbine disc on the three-coordinate inspection platform, with the first slot position kept in the Y-axis direction of the three-coordinate machine tool; S2, import the digital model, and according to the drawing requirements, use the three-coordinate probe to collect two points on the wheel reference surface, reference circle and two opposite working surfaces of the first slot to establish a coordinate system; S3, deconstruct the various dimensional elements that need to be measured for the mortise and tenon; S4, the three-coordinate system collects the geometric features in the mortise and tenon, constructs the corresponding dimensional elements for evaluation, and determines whether it meets the drawing requirements based on the preset tolerance threshold, and completes the inspection.

2. A three-coordinate detection and evaluation method for the tenon groove of a fir-tree-shaped turbine disk of a gas turbine according to claim 1, characterized in that: The S2 specifically includes the following steps: S2-1, evenly collect three points on the datum plane of the digital model of the wheel, evenly collect three points on the datum outer circle of the digital model of the wheel, construct the outer circle with three points, select one point from each of the left and right working surfaces in the mortise and tenon groove, and construct the midpoint with two points; S2-2, align the three points of the reference plane, rotate the outer circle to the midpoint, use the outer circle as the center of the coordinate system, use the iteration method to initially build the coordinate system, the reference plane is the coordinate system Z zero, the Z positive axis is perpendicular to the reference plane, and the outer circle is the origin of the coordinate system X and Y axes; S2-3, repeat the above two steps, in this step, the number of iterations of the iterative method is changed to 99 times, the tolerance is changed to the minimum tolerance of the drawing, and points are taken on the wheel to measure all the above features, and the above geometric features are continuously iterated until the iterative error between the actual part and the digital model meets the requirements; S2-4, select a sampling point at any position of the wheel to verify whether the X, Y, Z and vector direction of the sampling point and the digital-analog deviation value T meet the minimum tolerance.

3. The three-coordinate detection and evaluation method for the tenon groove of a fir-tree-shaped turbine disk of a gas turbine according to claim 1, characterized in that: The dimensional elements that need to be measured in S3 include: S3-1, mortise angle α: the inclination angle of the mortise relative to the axis of the wheel disc; S3-2, mortise and tenon N value: the positioning dimension of the mortise and tenon along the circumference of the wheel disc; S3-3, tenon groove P point: blade tenon root positioning point; S3-4, mortise center distance A1: the distance between the mortise point P and the center of the rotation axis in the straight line direction of the wheel disc; S3-5, mortise center distance A2: the distance between mortise point P and the bottom surface of the mortise; S3-6, mortise center distance U: the distance between the mortise point P and the outer circle of the wheel base; S3-7, inclination Q1: the deflection distance of the mortise and tenon working surface from the center axis by 100 degrees; S3-8, inclination Q2: the deviation 100 distance between the symmetry plane of the mortise and tenon and the radial plane; S3-9, mortise and tenon uniform distribution T1: position degree of each mortise and tenon.

4. A three-coordinate detection and evaluation method for the tenon groove of a fir-tree-shaped turbine disk of a gas turbine according to claim 3, characterized in that: The inclination Q1 is the inclination of the left evaluation line LL and the left working surface SL of the digital model tenon groove in the projection length of 100 mm, and the inclination of the right evaluation line RR and the right working surface SR of the digital model tenon groove in the projection length of 100 mm.

5. The three-coordinate detection and evaluation method for the tenon groove of a fir-tree-shaped turbine disk of a gas turbine according to claim 3, characterized in that: The inclination Q2 detection method 1: evaluate the inclination of the straight line FM and the dividing surface M1 in the digital model at a projection length of 100 mm; Detection method 2: evaluate the 3D distance between point P2 and plane F; Test method 3: Evaluate the 3D angle β between the measured midplane M and the midplane M1 in the digital model; Use three coordinates to assign / V=TAN(β*π / 180)*100.

6. A three-coordinate detection and evaluation method for the tenon groove of a fir-tree-shaped turbine disk of a gas turbine according to claim 1, characterized in that: The S4 specifically comprises the following steps: S4-1, use a three-coordinate probe to collect points or scan a pair of working surfaces of the part's mortise and tenon groove to construct the left side L and the right side R; S4-2, construct the measured median plane M of the left side L and the right side R; S4-3, offset the measured midplane M by the theoretical distance A4 in the vector direction, and construct the offset left plane L1 and the offset right plane R1; S4-4, offset the left surface L1 and the left surface L to construct the left straight line LL, offset the right surface R1 and the right surface R to construct the right straight line RR; S4-5, measure the part reference surface B, measure the part reference outer circle C, offset the part reference surface B by a theoretical distance A5 in the negative direction of the Z axis, and construct the offset reference surface B1; S4-6, construct a plane F perpendicular to the Y axis of the coordinate system; S4-7, bottom surface D of the structural part mortise and tenon groove; S4-8, construct the intersection line FM of plane F and measured median plane M, the line FM pierces the bottom surface D of the mortise groove, and constructs point D1; S4-9, projecting the part reference outer circle C onto the offset reference plane B1 to construct a projection circle C1; S4-10, the center of the projected circle C1 and the point P construct a straight line PC1, the straight line PC1 pierces the projected circle C1, and a point P1 is constructed; S4-11, collect the digital model of the left working surface SL and the right working surface SR of the tenon groove; the digital model dividing surface M1 of the construction surface SL and the surface SR; S4-11, construct a straight line 1 that is 100 mm away from point P in the positive direction of the X axis and whose vector direction is the Y axis; S4-12, straight line 1 pierces the measured construction point P2 of the midpoint M.

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