A dowel pin tenon blade tip measurement fixture and method
By designing a pin-type tenon blade tip measuring fixture and corresponding measurement method, the accuracy problem of pin-type tenon rotor blade tip measurement was solved, realizing efficient and stable tip height and angle measurement, which is suitable for automatic measurement of large batches of blades.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- AECC AVIATION POWER CO LTD
- Filing Date
- 2024-07-05
- Publication Date
- 2026-07-28
AI Technical Summary
In the existing technology, it is difficult to accurately measure the blade tip of the pin-type tenon rotor blade, especially when the blade is thin and easily deformed, resulting in large measurement errors. In addition, it is difficult to establish the coordinate system when measuring with a coordinate measuring machine.
Design a pin-type tenon blade tip measuring fixture, including a base, a positioning pin, a smooth pressure block, and a slider. The blade tenon is pressed by the cooperation of the positioning pin and the smooth pressure block to establish an initial coordinate system. Different measurement methods (theoretical point measurement or three-point measurement when there are countless moduli) are used to improve the measurement accuracy.
It simplifies the coordinate system establishment process, improves measurement efficiency and accuracy, and is particularly suitable for rapid measurement of large batches of blades. It is also suitable for rapid batch measurement of blade tip height and angle of pin-type tenon rotor blades based on coordinate measuring machines.
Smart Images
Figure CN118636079B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of mechanical processing inspection methods, specifically to a pin-type tenon blade tip measuring fixture and method. Background Technology
[0002] The measurement reference for a certain pin-type tenon rotor blade is on the inner hole and end face of the tenon. When using a coordinate measuring machine (CMM), the accessibility of the inner hole measurement is poor, and the establishment of the coordinate system is difficult. Blade height and angle are essential characteristics that compressor rotor blades must measure. Due to the influence of blade profile thickness, the measurable area of the blade tip is very small (the thickness D of the measurable surface of some blades is less than 1 mm). The given blade tip angle is in the direction of the engine axis. Along the direction of the engine axis, the blade body cannot be measured. When using a digital model for measurement, three points are selected at the blade tip of the theoretical digital model of the blade. The blade tip height and angle are indirectly evaluated through measurement and calculation, but the result has a large error. Summary of the Invention
[0003] To address the problem in existing technologies where the thinness of the blade makes it prone to deformation, leading to significant measurement errors as the points selected in the theoretical numerical model may not accurately represent the actual blade, this invention provides a pin-type tenon blade tip measurement fixture and method. This provides an efficient, stable, and accurate method for measuring the tip height and angle of pin-type tenon rotor blades in aero-engines.
[0004] This invention is achieved through the following technical solution: A pin-type tenon blade tip measuring fixture includes a base, a positioning pin, a smooth pressure block, a positioning block, and a slider. The positioning block is fixed on the base, and the positioning pin is disposed on the positioning block. The positioning pin is used to install the positioning hole of the pin-type blade tenon. The smooth pressure block and the slider are slidably disposed on the base, and the slider and the smooth pressure block are coaxially disposed relative to each other. A circular hole is made on the positioning block, and the axis of the circular hole is parallel to the surface of the base. The smooth pressing block and the slider are set opposite to each other on both sides of the axis of the circular hole. The smooth pressing block and the slider cooperate to press and position the tenon of the blade.
[0005] Preferably, the length of the locating pin is greater than the inner hole depth of the two dowel tenons.
[0006] Preferably, it also includes a support block and a clamping screw. The support block is fixed on the base, and the clamping screw is threadedly connected to the support block. The clamping screw passes through the support block and connects to the smooth pressure block. Preferably, it also includes a guide block and a movable screw. The guide block is fixed on the base and is arranged opposite to the support block. The smooth pressure block and the slider are both located between the support block and the guide block. The slider passes through the guide block and is connected to the movable screw. The slider and the guide block are slidably connected.
[0007] Preferably, the guide block is provided with a limiting groove, which is used to limit the movement distance of the moving screw; when the moving screw is engaged with the limiting groove, the center of the blade tenon hole is located on the axis of the positioning pin.
[0008] A method for using a pin-type tenon blade tip measuring fixture involves aligning the positioning hole of the pin-type blade tenon with the positioning pin of the measuring fixture and inserting it to connect the two, so that the end face of the blade tenon is in close contact with the positioning block, and then using a slider and a smooth pressure block to press the blade tenon tightly.
[0009] Preferably, a clearance fit is used between the locating pin and the locating hole of the tenon of the pin-type blade.
[0010] Preferably, the gap is no greater than 0.005 mm.
[0011] A method for measuring the tip of a pin-type tenon blade includes the following steps: Step 1: Use a pin-type tenon blade tip measuring fixture to clamp the pin-type tenon blade and establish an initial coordinate system with the base as the first measuring reference and the positioning pin as the second measuring reference. Step two: Use different measurement methods depending on whether there is a blade digital model or not.
[0012] Preferably, in step two, when there is a numerical model, the measurement is performed by taking theoretical points; when there is no numerical model, the measurement is performed by taking three points.
[0013] Preferably, when there are no moduloes, the specific operation of the three-point measurement is as follows: S1, Extract measurement points: For the actual blade, three points are measured at the blade base 1 mm away from the blade tip tenon, and recorded as PP1(X). P1 Y P1 Z P1 ), PP2(X P2 Y P2 Z P2 ), PP3(X P3 Y P3 Z P3 ); Three points were measured on the back of the blade, 1 mm away from the blade tip tenon, and denoted as PB1(X). B1 Y B1 Z B1 ), PB2(X B2 Y B2 Z B2 ), PB3(X B3 Y B3 Z B3Points PP1, PB1 and PP3, PB3 are located at 1 / 10 of the total blade tip length from the inlet and outlet edges of the blade, respectively, and points PP2 and PB2 are on the blade overlap axis. Measure three points at the tip of the leaf blade, denoted as P1(X1, Y1, Z1), P2(X2, Y2, Z2), and P3(X3, Y3, Z3), where X1 = X P1 =X B1 X2 = X P2 =X B2 =0、X3= X P3 =X B3 Y1 = (Y P1 +Y B1 ) / 2, Y2= (Y P2 +Y B2 ) / 2、Y3= (Y P3 +Y B3 ) / 2; S2, the measurement points P1 and P3 are transformed into PA1 and PA3 along the engine axis using trigonometric functions, that is, P1(X1, Y1, Z1) is transformed into point PA1(X1, Y1, Z2). A1 Point P3(X3, Y3, Z3) is transformed into point PA3(X3, Y3, Z3). A3 Z A1 = Z A3 = ; S3, calculate the blade tip angle based on the converted PA1 and PA3. θ And confirm θ Whether it is qualified or not, when θ In ( α - β )~( α + β When the blade tip angle is within acceptable limits, the blade tip angle is within acceptable limits. α It is the theoretical blade tip angle. β It's a tolerance; The blade tip height is deemed acceptable based on the Z value measured at point P2. When Z is within the tolerance range, the blade tip height is considered acceptable.
[0014] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a pin-type tenon rotor blade tip measuring fixture. By positioning the blade using this fixture, the process of establishing a coordinate system is simplified, improving measurement efficiency. Different measurement methods can be selected for different measurement conditions, enabling the measurement and evaluation of blade tip height and angle. Without moving the measuring fixture, the original coordinate system only needs to be established once during manual measurement; all other measurements are performed automatically. This method is particularly suitable for measuring large batches of blades and can be extended to automatic blade measurement units. It is applicable to the rapid batch measurement of blade tip height and angle using a coordinate measuring machine-based pin-type tenon rotor blade.
[0015] Because the blade blade is relatively thin and prone to deformation, the points selected in the theoretical model may not necessarily be able to measure the actual blade. It is necessary to take one point each on the blade's base and back, calculate the blade tip measurement position, and obtain the blade tip height and angle values through measurement and calculation. Without a theoretical model, it is necessary to measure the three points at the blade tip and then calculate to transfer the measured points to the engine axis. Attached Figure Description
[0016] Figure 1 A schematic diagram of a dowel-type tenon blade; Figure 2 This is a front view of a pin-type tenon blade tip measuring fixture according to the present invention; Figure 3 This is a top view of a pin-type tenon blade tip measuring fixture according to the present invention; Figure 4 This is a schematic diagram of a smooth-surfaced pressing block; Figure 5 This is a schematic diagram of the movable screw; Figure 6 This is a schematic diagram of the boot block; Figure 7 A schematic diagram of the measurement characteristics of the blade tip; Figure 8 A schematic diagram of the coordinate measurement at the blade tip; Figure 9 This is a schematic diagram of the engine's cross-section.
[0017] In the diagram, 1 is the locating pin; 2 is the cylindrical pin; 3 is the base; 4 is the first connecting screw; 5 is the support block; 6 is the clamping screw; 7 is the smooth pressing block; 8 is the locating block; 9 is the guide block; 10 is the slider; 11 is the second connecting screw; 12 is the cover plate; and 13 is the moving screw. Detailed Implementation
[0018] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.
[0019] This invention discloses a pin-type tenon blade tip measuring fixture, with reference to Figure 2 , 3 It includes a base 3, a positioning pin 1, a smooth pressing block 7, a positioning block 8, and a slider 10. The positioning block 8 is fixed to the base 3 by a cylindrical pin 2. The positioning pin 1 is set on the positioning block 8. The positioning pin 1 is used to install the positioning hole of the pin-type leaf tenon. The length of the positioning pin 1 is greater than the inner hole depth of the two pin-type tenons.
[0020] A circular hole is made on the positioning block 8. The axis of the circular hole is parallel to the surface of the base 3. The smooth pressing block 7 and the slider 10 are arranged opposite to each other on both sides of the axis of the circular hole. The smooth pressing block 7 is used to press and position the blade tenon, and the slider 10 is used to press and position the blade tenon. That is, the smooth pressing block 7 and the slider 10 cooperate to press and position the blade tenon.
[0021] Reference Figure 2 , 3 4. The smooth pressing block 7 and the slider 10 are slidably disposed on the base 3, and the slider 10 and the smooth pressing block 7 are coaxially disposed relative to each other. In this embodiment, the smooth pressing block 7 is installed by a support block 5 and a clamping screw 6. The support block 5 is fixed to the base 3 by a cylindrical pin 2. The clamping screw 6 is threadedly connected to the support block 5, and the clamping screw 6 passes through the support block 5 and connects to the smooth pressing block 7. The smooth pressing block 7 moves left and right under the drive of the clamping screw 6.
[0022] Reference Figure 2 , 5 6. The slider 10 is installed via the guide block 9 and the moving screw 13. The guide block 9 is positioned opposite the support block 5 and is fixed to the base 3 by the cylindrical pin 2. The smooth pressure block 7 and the slider 10 are both located between the support block 5 and the guide block 9. The slider 10 passes through the guide block 9 and is connected to the moving screw 13. The slider 10 and the guide block 9 are in a smooth sliding connection. The moving screw 13 drives the guide block 9 to move left and right. In this embodiment, the slider 10 is installed through the top opening of the guide block 9. The opening is fixed to the cover plate 12 by the second connecting screw 11.
[0023] In this embodiment, a limiting groove is provided on the guide block 9. The limiting groove is used to limit the movement distance of the moving screw 13. When the moving screw 13 is engaged with the limiting groove, the center of the blade tenon hole is located on the axis of the positioning pin 1.
[0024] This invention also discloses a method for using a pin-type tenon blade tip measuring fixture. The positioning hole of the pin-type blade tenon is aligned with the positioning pin 1 of the measuring fixture and inserted to connect them, ensuring the blade tenon end face is firmly against the positioning block 8. Then, the blade tenon is pressed tightly using the slider 10 and the smooth pressure block 7. The positioning pin 1 and the positioning hole of the pin-type blade tenon are fitted with a clearance fit, and the clearance is no greater than 0.005 mm.
[0025] This invention also discloses a method for measuring the tip of a pin-type tenon blade, comprising the following steps: Step 1: Use a pin-type tenon blade tip measuring fixture to clamp the pin-type tenon blade and establish an initial coordinate system with base 3 as the first measuring reference and positioning pin 1 as the second measuring reference. Step two: Use different measurement methods depending on whether there is a blade digital model or not.
[0026] Preferably, in step two, when there is a numerical model, the measurement is performed by taking theoretical points; when there is no numerical model, the measurement is performed by taking three points.
[0027] Taking a pin-type tenon blade as an example, the blade tip measurement process is as follows: Step 1: Use a pin-type tenon blade tip measuring fixture to clamp the pin-type tenon blade and establish an initial coordinate system with base 3 as the first measuring reference and positioning pin 1 as the second measuring reference. Install the blade: Support the measuring instrument with three pads and fix it to the measuring machine platform with the first connecting screw 4 and the screw rod. Insert the blade pin hole into the positioning pin 1 so that the blade tenon end face is in close contact with the positioning block 8. First tighten the moving screw 13, and then tighten the embossed round head clamping screw 6.
[0028] Establish the initial coordinate system: Measure a plane on the bottom surface of base 33 to determine the direction of the Z-axis of the coordinate system. Measure positioning pin 11 to determine the direction of the Y-axis and the zero points of the X and Z axes. Measure a point on the end face of positioning block 88 to determine the zero point of the Y-axis. Then, offset the Y-axis zero point by value B and the Z-axis zero point by value L, and save this coordinate system as the external coordinate system. When batch measuring blades without moving the measuring tool, there is no need to re-establish the coordinate system or change blades; simply call the external coordinate system to directly measure the blade tip height and angle. Here, B is the distance from the blade end face to the blade overlap axis, and L is the distance from the center of the pin-type tenon hole to the engine center.
[0029] Step two: Use different measurement methods depending on whether there is a blade digital model or not.
[0030] When a digital model is available, the measurement is performed using theoretical points, as detailed below: (1) Taking the theoretical point The theoretical point is extracted from the tip of the theoretical numerical model of the measured blade, referring to... Figure 7 , 8 Three points PP1(X) were extracted at the leaf base, 1 mm from the leaf tip towards the tenon. P1 Y P1 Z P1 ), PP2(X P2 Y P2Z P2 ), PP3(X P3 Y P3 Z P3 ), extract three points PB1(X) on the underside of the leaf, 1 mm from the leaf tip towards the tenon. B1 Y B1 Z B1 ), PB2(X B2 Y B2 Z B2 ), PB3(X B3 Y B3 Z B3 Points PP1, PB1 and PP3, PB3 are located at 1 / 10 of the total blade tip length from the inlet and outlet edges of the blade, respectively. Points PP2 and PB2 are on the blade overlap axis. Theoretical points P1(X1, Y1, Z1), P2(X2, Y2, Z2), and P3(X3, Y3, Z3) are taken at the blade tip, where X1 = X P1 =X B1 X2 = X P2 =X B2 =0、X3= X P3 =X B3 Z P1 = Z B1 Z P3 = Z B3 Y1 = (Y P1 +Y B1 ) / 2, Y2=(Y P2 +Y B2 ) / 2、Y3= (Y P3 +Y B3 ) / 2.
[0031] (2) Measurement Measurement point PP1(X) P1 Y P1 Z P1 ), PP2(X P2 Y P2 Z P2 ), PP3(X P3 Y P3 Z P3 ), PB1(X B1 Y B1 Z B1 ), PB2(X B2 Y B2 Z B2 ), PB3(X B3 Y B3 Z B3), P1(X1, Y1, Z1), P2(X2, Y2, Z2), P3(X3, Y3, Z3).
[0032] (3) Analysis By comparing the Z values of measurement points P1 and P3 with the digital model, the Z coordinate deviation ΔZ and the measured X coordinate values of points P1 and P3 are analyzed, and the angle is calculated. β =arctg (△Z1- △Z3) / (X1-X3) is considered acceptable if the deviation of the Z value at measurement point P2, △Z2, is within the tolerance range of the blade tip angle.
[0033] For non-linear measurements, a three-point method is used, as follows: (1) Measurement For the actual blade, measure three points PP1(X) at the leaf base, 1 mm away from the blade tip and moving towards the tenon. p1 Y P1 Z P1 ), PP2(X P2 Y P2 Z P2 ), PP3(X P3 Y P3 Z P3 ), extract three points PB1(X) on the underside of the leaf, 1 mm from the leaf tip towards the tenon. B1 Y B1 Z B1 ), PB2(X B2 Y B2 Z B2 ), PB3(X B3 Y B3 Z B3 Points PP1, PB1 and PP3, PB3 are located at 1 / 10 of the total blade tip length from the inlet and exhaust edges of the blade, respectively. Points PP2 and PB2 are on the blade overlap axis. P1 =X B1 X P2 =X B2 =0、X P3 =X B3 Z P1 = Z B1 Z P3 = Z B3 The blade tip thickness D1 is equal to the Y-axis distance between PB1 and PP1, the blade tip thickness D2 is equal to the Y-axis distance between PB2 and PP2, and the blade tip thickness D3 is equal to the Y-axis distance between PB3 and PP3.
[0034] Measurement points are P1(X1, Y1, Z1), P2(X2, Y2, Z2), and P3(X3, Y3, Z3) at the leaf tip, where X1 = X P1 =X B1 X2 = X P2 =X B2 =0、X3= X P3 =X B3 Y1 = (Y P1 +Y B1 ) / 2, Y2= (Y P2 +Y B2 ) / 2, Y3=(Y P3 +Y B3 ) / 2.
[0035] (2) Transformation Reference Figure 9 The measurement points P1(X1, Y1, Z1) and P3(X3, Y3, Z3) are transformed to the direction of the engine axis using trigonometric functions. Point P1(X1, Y1, Z1) is transformed into point PA1(X1, Y1, Z3). A1 Point P3(X3, Y3, Z3) is transformed into point PA3(X3, Y3, Z3). A3 Assignment: Z A1 = Z A3 = .
[0036] (3) Analysis Calculate the tip angle based on the converted PA1 and PA3. θ And confirm θ Whether it is qualified or not, when θ In ( α - β )~( α + β When the blade tip angle is within acceptable limits, the blade tip angle is within acceptable limits. α It is the theoretical blade tip angle. β It's a tolerance; The measured Z value of measurement point P2 is considered qualified if it falls within the range of blade tip height (H+L)+a and (H+L)-a, where H is the theoretical height of the blade, L is the distance from the blade zero point to the engine shaft center, and a is the tolerance.
[0037] The above description is merely a preferred embodiment of the present invention and is not intended to limit the technical solution of the present invention in any way. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solution can be modified and replaced in several simple ways, and these modifications and replacements are all within the scope of protection covered by the claims.
Claims
1. A method for measuring the tip of a dowel-type tenon blade, characterized in that, Includes the following steps: Step 1: Use a pin-type tenon blade tip measuring fixture to clamp the pin-type tenon blade and establish an initial coordinate system with the base (3) as the first measuring reference and the positioning pin (1) as the second measuring reference. The pin-type tenon blade tip measuring fixture includes a base (3), a positioning pin (1), a smooth pressing block (7), a positioning block (8), and a slider (10). The positioning block (8) is fixed on the base (3), and the positioning pin (1) is set on the positioning block (8). The positioning pin (1) is used to install the positioning hole of the pin-type blade tenon. The smooth pressing block (7) and the slider (10) are slidably set on the base (3), and the slider (10) and the smooth pressing block (7) are coaxially arranged relative to each other. A circular hole is made on the positioning block (8), the axis of the circular hole is parallel to the surface of the base (3), and the smooth pressing block (7) and the slider (10) are arranged opposite to each other on both sides of the axis of the circular hole. The smooth pressing block (7) and the slider (10) cooperate to press and position the blade tenon. Step two: Different measurement methods are used depending on whether there is a blade digital model. When there is a digital model, the measurement is performed by taking theoretical points; when there is no digital model, the measurement is performed by three points. When there are no moduli, the specific operation for three-point measurement is as follows: S1, Extract measurement points: For the actual blade, three points are measured at the blade base 1 mm away from the blade tip tenon, and recorded as PP1(X). P1 Y P1 Z P1 ), PP2(X P2 Y P2 Z P2 ), PP3(X P3 Y P3 Z P3 ); Three points were measured on the back of the blade, 1 mm away from the blade tip tenon, and denoted as PB1(X). B1 Y B1 Z B1 ), PB2(X B2 Y B2 Z B2 ), PB3(X B3 Y B3 Z B3 Points PP1, PB1 and PP3, PB3 are located at 1 / 10 of the total blade tip length from the inlet and outlet edges of the blade, respectively, and points PP2 and PB2 are on the blade overlap axis. Measure three points at the tip of the leaf blade, denoted as P1(X1, Y1, Z1), P2(X2, Y2, Z2), and P3(X3, Y3, Z3), where X1 = X P1 =X B1 X2 = X P2 =X B2 =0、X3= X P3 =X B3 Y1 = (Y P1 +Y B1 ) / 2, Y2= (Y P2 +Y B2 ) / 2、Y3= (Y P3 +Y B3 ) / 2; S2, the measurement points P1 and P3 are transformed into PA1 and PA3 along the engine axis using trigonometric functions, that is, P1(X1, Y1, Z1) is transformed into point PA1(X1, Y1, Z2). A1 Point P3(X3, Y3, Z3) is transformed into point PA3(X3, Y3, Z3). A3 Z A1 = Z A3 = ; S3, calculate the blade tip angle based on the converted PA1 and PA3. θ And confirm θ Whether it is qualified or not, when θ In ( α - β )~( α + β When the blade tip angle is within acceptable limits, the blade tip angle is within acceptable limits. α It is the theoretical blade tip angle. β It's a tolerance; The blade tip height is deemed acceptable based on the Z value measured at point P2. When Z is within the tolerance range, the blade tip height is considered acceptable.
2. The method for measuring the tip of a dowel-type blade according to claim 1, characterized in that, The length of the locating pin (1) is greater than the depth of the inner hole of the two dowel tenons.
3. The method for measuring the tip of a dowel-type blade according to claim 1, characterized in that, It also includes a support block (5) and a clamping screw (6). The support block (5) is fixed on the base (3), and the clamping screw (6) is threadedly connected to the support block (5). The clamping screw (6) passes through the support block (5) and connects to the smooth pressure block (7).
4. The method for measuring the tip of a dowel-type blade according to claim 1, characterized in that, It also includes a guide block (9) and a moving screw (13). The guide block (9) is fixed on the base (3). The guide block (9) is set opposite to the support block (5). The smooth pressure block (7) and the slider (10) are both located between the support block (5) and the guide block (9). The slider (10) passes through the guide block (9) and is connected to the moving screw (13). The slider (10) and the guide block (9) are smoothly connected.
5. The method for measuring the tip of a dowel-type blade according to claim 1, characterized in that, The guide block (9) is provided with a limiting groove, which is used to limit the movement distance of the moving screw (13); when the moving screw (13) is engaged with the limiting groove, the center of the blade tenon hole is located on the axis of the positioning pin (1).
6. The method for measuring the tip of a pin-type tenon blade according to claim 1, characterized in that, The method of using the pin-type tenon blade tip measuring fixture is as follows: align the positioning hole of the pin-type blade tenon with the positioning pin (1) of the measuring fixture and insert it to connect the two, so that the end face of the blade tenon is in close contact with the positioning block (8), and then use the slider (10) and the smooth pressing block (7) to press the blade tenon.
7. The method for measuring the tip of a pin-type tenon blade according to claim 6, characterized in that, The positioning pin (1) and the positioning hole of the tenon of the pin-type blade adopt a clearance fit.
8. The method for measuring the tip of a dowel-type blade according to claim 7, characterized in that, The gap should not exceed 0.005mm.