A method for docking and assembling a low-pressure turbine shaft and a grate disc of an aircraft engine

Abstract

A method for docking and assembling a low-pressure turbine shaft and a grate disc of an aero-engine, comprising the following steps: mounting the low-pressure turbine shaft and the grate disc on a fixture; clamping and loosening the low-pressure turbine shaft by controlling the screwing-in and screwing-out amounts of the fixture bolts; measuring the flange end faces of the low-pressure turbine shaft and the grate disc by a three-coordinate measuring instrument to obtain position coordinate information, feeding back motion instructions to a posture adjustment platform to achieve a coplanar position; measuring the spigot cylindrical surfaces of the low-pressure turbine shaft and the grate disc by a three-coordinate measuring instrument to obtain position coordinate information, feeding back motion instructions to the posture adjustment platform to achieve a concentric position; photographing the bolt holes of the low-pressure turbine shaft and the grate disc by a visual system to obtain a center-of-circle spacing value, feeding back motion instructions to the posture adjustment platform to achieve bolt hole centering; heating the spigot connection of the low-pressure turbine shaft by a heating system; and extending the spigot after the heating temperature reaches the requirement, thereby completing the docking and assembly of the low-pressure turbine shaft and the grate disc.

Description

Technical Field

[0001] The invention belongs to the technical field of aero-engine assembly, and relates to a method for butting and assembling a low-pressure turbine shaft and a grate disc of an aero-engine. Background Art

[0002] Aeroengine assembly is the final and core stage of the aircraft engine manufacturing process, and assembly quality directly impacts the engine's service performance. Aeroengine rotors are assembled in series, with rotor components being rigid rotating bodies with end connections. Flanges and spigots are the most typical connection structures between rotor components. Adjacent rotor components are positioned relative to each other in the axial direction and along the axis via the flange end faces, radially relative to each other via the spigots, and circumferentially relative to each other via connection holes distributed around the flange's outer edge.

[0003] The commonly used manual method for aircraft engine installation suffers from low automation, low attitude adjustment accuracy, and low installation efficiency. In recent years, the gradual implementation of multi-degree-of-freedom attitude adjustment mechanisms has significantly improved docking assembly accuracy. However, efficiency and safety remain to be improved, and research on guidance methods for the docking assembly process is lacking.

[0004] The docking and assembly process between the low-pressure turbine shaft and the grate disc is primarily plagued by low first-pass docking success rates, high assembly process variability, and the susceptibility to bumps and scratches. Furthermore, since the joint surfaces cannot be re-inspected after assembly, high requirements are placed on the measurement device's single-shot positioning accuracy and reliability. Summary of the Invention

[0005] The present invention aims to address the problems existing in the prior art by providing a method for docking and assembling a low-pressure turbine shaft and a grate disc of an aircraft engine. By following the relevant steps in the docking flow chart, the low-pressure turbine shaft and the grate disc can be docked and assembled efficiently and with high quality, ensuring smooth installation of the aircraft engine.

[0006] The technical solution of the present invention:

[0007] A method for docking and assembling a low-pressure turbine shaft and a grate disc of an aircraft engine, comprising the following steps:

[0008] S1. Install the low-pressure turbine shaft and the grate disc, ensuring that the axis deviation of the low-pressure turbine shaft is within the specified reasonable range after installation, and that the flange end face of the grate disc is perpendicular to the ground after installation;

[0009] S2. Use a three-coordinate measuring instrument to measure the end face of the grate disc flange and the end face of the low-pressure turbine shaft flange to obtain point cloud data (x1, y1, z1) of the measuring points on the grate disc flange end face and point cloud data (x2, y2, z2) of the measuring points on the low-pressure turbine shaft flange end face. Use the least squares method to perform plane fitting on the point cloud data (x1, y1, z1) and (x2, y2, z2) of the measuring points to obtain a fitting plane of the grate disc flange end face and a fitting plane of the low-pressure turbine shaft flange end face.

[0010] Calculate the spatial angle θ1 between the normal vectors of the fitting plane of the grate disc flange end face and the fitting plane of the low-pressure turbine shaft flange end face, and adjust the spatial angle θ1 to 0, that is, to achieve the coplanarity of the low-pressure turbine shaft flange end face and the grate disc flange end face;

[0011] The spatial angle θ1 between the normal vectors of the fitting plane of the grate disc flange end face and the fitting plane of the low-pressure turbine shaft flange end face is calculated as follows:

[0012]

[0013] Where: θ1 is the spatial angle between the normal vectors of the fitting plane of the grate disc flange end face and the fitting plane of the low-pressure turbine shaft flange end face, unit: °; a1, b1, c1 are the fitting plane parameters of the grate disc flange end face; a2, b2, c2 are the fitting plane parameters of the low-pressure turbine shaft flange end face;

[0014] S3. Use a three-coordinate measuring machine to measure the convex spigot cylindrical surface of the grate disc and the concave spigot cylindrical surface of the low-pressure turbine shaft, and obtain the measuring point data of the convex spigot cylindrical surface of the grate disc as (x3, y3, z3), and the measuring point data of the concave spigot cylindrical surface of the low-pressure turbine shaft as (x4, y4, z4). Project the measuring point data (x3, y3, z3) of the convex spigot cylindrical surface of the grate disc onto the fitting plane of the grate disc flange end face to obtain the mapping point cloud data (x5, y5, z5), projecting the low-pressure turbine shaft concave spigot cylindrical surface measurement point data (x4, y4, z4) onto the fitting plane of the low-pressure turbine shaft flange end face to obtain the mapping point cloud data (x6, y6, z6), and performing plane circle fitting on the mapping point cloud data (x5, y5, z5) and (x6, y6, z6) using the least squares method to obtain the spatial center O1 of the convex spigot cylindrical surface of the grate disc and the spatial center O2 of the concave spigot cylindrical surface of the low-pressure turbine shaft;

[0015] Calculate the spatial angle θ2 between the line vector u connecting the spatial center of the convex spigot cylindrical surface of the grate disc and the spatial center of the low-pressure turbine shaft spigot cylindrical surface and the normal vector n of the fitting plane of the grate disc flange end face, and adjust the spatial angle to 0, that is, to achieve the concentricity of the spatial center of the concave spigot cylindrical surface of the low-pressure turbine shaft and the spatial center of the convex spigot cylindrical surface of the grate disc;

[0016] The spatial angle θ2 between the line vector u connecting the center O1 of the convex spigot cylindrical surface of the grate disc and the center O2 of the concave spigot cylindrical surface of the low-pressure turbine shaft and the normal vector n of the fitting plane of the grate disc flange end face is calculated as follows:

[0017]

[0018] Where: θ2 is the spatial angle between the line vector connecting the center of the cylindrical surface of the convex spigot of the grate disc and the center of the cylindrical surface of the concave spigot of the low-pressure turbine shaft and the surface, unit: °; u is the line vector connecting the center of the cylindrical surface of the convex spigot of the grate disc O1 and the center of the cylindrical surface of the concave spigot of the low-pressure turbine shaft O2; n is the normal vector of the fitting plane of the end face of the grate disc flange;

[0019] S4. Use an industrial camera equipped with a dual-view prism to photograph a pair of bolt holes on the end face of the grate disc flange and the end face of the low-pressure turbine shaft flange;

[0020] Calculate the circumferential relative angle Δβ between a pair of bolt holes on the end face of the grate disc flange and the end face of the low-pressure turbine shaft flange. Adjust the circumferential relative angle to 0 to align the bolt holes on the end face of the low-pressure turbine shaft flange with the end face of the grate disc flange.

[0021] The circumferential relative angle Δβ between a pair of bolt holes on the end face of the grate disc flange and the end face of the low-pressure turbine shaft flange is calculated as follows:

[0022]

[0023] Where: Δβ is the circumferential relative angle between the pair of bolt holes on the end face of the grate disc flange and the end face of the low-pressure turbine shaft flange, unit: °; D is the actual center distance between the pair of bolt holes on the end face of the grate disc flange and the end face of the low-pressure turbine shaft flange, unit: mm; R is the distance from the bolt holes on the end face of the grate disc flange and the end face of the low-pressure turbine shaft flange to the center of the circle, unit: mm;

[0024] S5. Heat the low-pressure turbine shaft recess and monitor the temperature to ensure that the heating temperature reaches 350°C and the maximum temperature does not exceed 380°C. The holding time is 10 minutes.

[0025] S6. Use an industrial camera to photograph the butt clearance between the low-pressure turbine shaft and the grate disc, calculate the butt clearance d between the low-pressure turbine shaft and the grate disc, and adjust the butt clearance to 0, thus achieving the spigot insertion action;

[0026] S7. Monitor the collision force during the insertion of the stopper, and require that the collision force be less than the specified value to prevent damage to the workpiece and digital sensor caused by collision. If the collision force is normal, continue to insert the stopper until the butt joint surfaces are in contact; complete the butt joint assembly of the low-pressure turbine shaft and the grate disc.

[0027] Beneficial effects of the present invention: According to the method of the present invention, the low-pressure turbine shaft and the comb disc can be docked and assembled with high efficiency and high quality, ensuring the smooth installation of the aircraft engine. The method of the present invention formulates the assembly route of the low-pressure turbine shaft and the comb disc according to the structural characteristics of the low-pressure turbine unit body and the requirements of the test system. It is implemented according to the steps in the flow chart, which can reduce human intervention and errors in operation, improve the one-time docking success rate of the aircraft engine unit body, reduce the dispersion of the assembly process, and reduce the risk of bumps and scratches, thereby improving the efficiency and quality of engine assembly. The method of the present invention is simple and easy to implement, with clear logic and low safety risks, which makes it convenient for operators to quickly master the docking assembly technology of the low-pressure turbine shaft and the comb disc. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a flow chart of a method for docking and assembling a low-pressure turbine shaft and a grate disc of an aero-engine according to an embodiment of the present invention;

[0029] Figure 2 Schematic diagram of calculating the angle between the normal vector space between the fitting plane of the low-pressure turbine shaft flange end face and the fitting plane of the grate disc flange end face according to an embodiment of the present invention; (a) is the case where they are not coplanar, and (b) is the case where they are coplanar;

[0030] Figure 3 Schematic diagram of calculating the spatial angle θ2 between the line vector u connecting the spatial center O1 of the grate disc convex spigot cylindrical surface and the spatial center O2 of the low-pressure turbine shaft spigot cylindrical surface and the normal vector n of the fitting plane of the grate disc flange end face according to an embodiment of the present invention; wherein (a) is the non-concentric case, and (b) is the concentric case;

[0031] Figure 4 Schematic diagram of calculating the circumferential relative angle of a pair of bolt holes on the end face of a low-pressure turbine shaft flange and the end face of a grate disc flange according to an embodiment of the present invention; (a) is a schematic diagram of the calculation of the circumferential relative angle of the bolt holes, and (b) is a partial enlarged view of the calculation of the circumferential relative angle of the bolt holes;

[0032] Figure 5 The figure is a schematic diagram of the connection between the low-pressure turbine shaft and the grate disc of an aero-engine according to an embodiment of the present invention. DETAILED DESCRIPTION

[0033] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and technical solutions.

[0034] The assembly accuracy of aero-engine rotor parts is a key indicator to ensure the efficient and stable operation of the entire machine, and the assembly quality directly affects the service performance of the engine.

[0035] See also Figure 1 A method for docking and assembling a low-pressure turbine shaft of an aircraft engine and a grate disc comprises the following steps:

[0036] Start the docking assembly of the low-pressure turbine shaft and the grate disc;

[0037] S1. Install the low-pressure turbine shaft and the grate disc, ensuring that the axis deviation of the low-pressure turbine shaft is within the specified reasonable range after installation, and that the flange end face of the grate disc is perpendicular to the ground after installation;

[0038] S2. Use a three-coordinate measuring instrument to measure the end face of the grate disc flange and the end face of the low-pressure turbine shaft flange to obtain point cloud data (x1, y1, z1) of the measuring points on the grate disc flange end face and point cloud data (x2, y2, z2) of the measuring points on the low-pressure turbine shaft flange end face. Use the least squares method to perform plane fitting on the point cloud data (x1, y1, z1) and (x2, y2, z2) of the measuring points to obtain a fitting plane of the grate disc flange end face and a fitting plane of the low-pressure turbine shaft flange end face.

[0039] The measuring points of the grate disc flange end face and the low-pressure turbine shaft flange end face adopt a double-ring, evenly distributed measuring point scheme with 28 measuring points. The radius of the first ring is R1 = 149 mm, and the radius of the second ring is R2 = 125 mm.

[0040] Calculate the spatial angle θ1 between the normal vectors of the fitting plane of the grate disc flange end face and the fitting plane of the low-pressure turbine shaft flange end face, and adjust the spatial angle θ1 to 0, that is, to achieve the coplanarity of the low-pressure turbine shaft flange end face and the grate disc flange end face;

[0041] The spatial angle θ1 between the normal vectors of the fitting plane of the grate disc flange end face and the fitting plane of the low-pressure turbine shaft flange end face is calculated as follows:

[0042]

[0043] Where: θ1 is the spatial angle between the normal vectors of the fitting plane of the grate disc flange end face and the fitting plane of the low-pressure turbine shaft flange end face, unit: °; a1, b1, c1 are the fitting plane parameters of the grate disc flange end face; a2, b2, c2 are the fitting plane parameters of the low-pressure turbine shaft flange end face;

[0044] S3. Use a three-coordinate measuring machine to measure the convex spigot cylindrical surface of the grate disc and the concave spigot cylindrical surface of the low-pressure turbine shaft, and obtain the measuring point data of the convex spigot cylindrical surface of the grate disc as (x3, y3, z3), and the measuring point data of the concave spigot cylindrical surface of the low-pressure turbine shaft as (x4, y4, z4). Project the measuring point data (x3, y3, z3) of the convex spigot cylindrical surface of the grate disc onto the fitting plane of the grate disc flange end face to obtain the mapping point cloud data (x5, y5, z5), projecting the low-pressure turbine shaft concave spigot cylindrical surface measurement point data (x4, y4, z4) onto the fitting plane of the low-pressure turbine shaft flange end face to obtain the mapping point cloud data (x6, y6, z6), and performing plane circle fitting on the mapping point cloud data (x5, y5, z5) and (x6, y6, z6) using the least squares method to obtain the spatial center O1 of the convex spigot cylindrical surface of the grate disc and the spatial center O2 of the concave spigot cylindrical surface of the low-pressure turbine shaft;

[0045] The measurement point strategy for the convex spigot cylindrical surface of the grate disc and the concave spigot cylindrical surface of the low-pressure turbine shaft adopts a single-ring evenly distributed measurement point scheme with 36 measurement points;

[0046] Calculate the spatial angle θ2 between the line vector u connecting the spatial center of the convex spigot cylindrical surface of the grate disc and the spatial center of the low-pressure turbine shaft spigot cylindrical surface and the normal vector n of the fitting plane of the grate disc flange end face, and adjust the spatial angle to 0, that is, to achieve the concentricity of the spatial center of the concave spigot cylindrical surface of the low-pressure turbine shaft and the spatial center of the convex spigot cylindrical surface of the grate disc;

[0047] The spatial angle θ2 between the line vector u connecting the center O1 of the convex spigot cylindrical surface of the grate disc and the center O2 of the concave spigot cylindrical surface of the low-pressure turbine shaft and the normal vector n of the fitting plane of the grate disc flange end face is calculated as follows:

[0048]

[0049] Where: θ2 is the spatial angle between the line vector connecting the center of the cylindrical surface of the convex spigot of the grate disc and the center of the cylindrical surface of the concave spigot of the low-pressure turbine shaft and the surface, unit: °; u is the line vector connecting the center of the cylindrical surface of the convex spigot of the grate disc O1 and the center of the cylindrical surface of the concave spigot of the low-pressure turbine shaft O2; n is the normal vector of the fitting plane of the end face of the grate disc flange;

[0050] S4. Use an industrial camera equipped with a dual-view prism to photograph a pair of bolt holes on the end face of the grate disc flange and the end face of the low-pressure turbine shaft flange;

[0051] Calculate the circumferential relative angle Δβ between a pair of bolt holes on the end face of the grate disc flange and the end face of the low-pressure turbine shaft flange. Adjust the circumferential relative angle to 0 to align the bolt holes on the end face of the low-pressure turbine shaft flange with the end face of the grate disc flange.

[0052] The circumferential relative angle Δβ between a pair of bolt holes on the end face of the grate disc flange and the end face of the low-pressure turbine shaft flange is calculated as follows:

[0053]

[0054] Where: Δβ is the circumferential relative angle between the pair of bolt holes on the end face of the grate disc flange and the end face of the low-pressure turbine shaft flange, unit: °; D is the actual center distance between the pair of bolt holes on the end face of the grate disc flange and the end face of the low-pressure turbine shaft flange, unit: mm; R is the distance from the bolt holes on the end face of the grate disc flange and the end face of the low-pressure turbine shaft flange to the center of the circle, unit: mm;

[0055] S5. Heat the low-pressure turbine shaft recess and monitor the temperature to ensure that the heating temperature reaches 350°C and the maximum temperature does not exceed 380°C. The holding time is 10 minutes.

[0056] S6. Use an industrial camera to photograph the butt clearance between the low-pressure turbine shaft and the grate disc, calculate the butt clearance d between the low-pressure turbine shaft and the grate disc, and adjust the butt clearance to 0, thus achieving the spigot insertion action;

[0057] S7. Monitor the collision force during the insertion of the stopper, and ensure that the collision force is less than the specified value to prevent damage to the workpiece and the digital sensor caused by collision. If the collision force is normal, continue to insert the stopper until the mating surfaces are in contact.

[0058] Complete the docking assembly of the low-pressure turbine shaft and the grate disc.

[0059] The method for docking and assembling the low-pressure turbine shaft and the grate disc of an aircraft engine proposed in an embodiment of the present invention is simple and easy to implement under existing conditions, has clear logic, and has low safety risks, and can meet the requirements for docking and assembling the low-pressure turbine shaft and the grate disc of an aircraft engine. The method proposed in the present invention is used to perform docking installation or debugging of the low-pressure turbine shaft and the grate disc of an aircraft engine, so that the installer can quickly master the docking skills of the low-pressure turbine shaft and the grate disc, master the technical points of the whole machine assembly, and promote the product to meet the conditions for the delivery of the whole machine.

[0060] The above-described embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present application, and should all be included in the scope of protection of the present application.

Claims

1. A method for docking and assembling a low-pressure turbine shaft of an aircraft engine and a grate disc, characterized in that: Here are the steps: S1. Install the low-pressure turbine shaft and the grate disc, ensuring that the axis deviation of the low-pressure turbine shaft is within the specified reasonable range after installation, and that the flange end face of the grate disc is perpendicular to the ground after installation; S2. Use a three-coordinate measuring instrument to measure the end face of the grate disc flange and the end face of the low-pressure turbine shaft flange to obtain point cloud data (x1, y1, z1) of the measuring points on the grate disc flange end face and point cloud data (x2, y2, z2) of the measuring points on the low-pressure turbine shaft flange end face. Use the least squares method to perform plane fitting on the point cloud data (x1, y1, z1) and (x2, y2, z2) of the measuring points to obtain a fitting plane of the grate disc flange end face and a fitting plane of the low-pressure turbine shaft flange end face. Calculate the spatial angle θ1 between the normal vectors of the fitting plane of the grate disc flange end face and the fitting plane of the low-pressure turbine shaft flange end face, and adjust the spatial angle θ1 to 0, that is, to achieve the coplanarity of the low-pressure turbine shaft flange end face and the grate disc flange end face; The spatial angle θ1 between the normal vectors of the fitting plane of the grate disc flange end face and the fitting plane of the low-pressure turbine shaft flange end face is calculated as follows: Where: θ1 is the spatial angle between the normal vectors of the fitting plane of the grate disc flange end face and the fitting plane of the low-pressure turbine shaft flange end face, unit: °; a1, b1, c1 are the fitting plane parameters of the grate disc flange end face; a2, b2, c2 are the fitting plane parameters of the low-pressure turbine shaft flange end face; S3. Use a three-coordinate measuring machine to measure the convex spigot cylindrical surface of the grate disc and the concave spigot cylindrical surface of the low-pressure turbine shaft, and obtain the measuring point data of the convex spigot cylindrical surface of the grate disc as (x3, y3, z3), and the measuring point data of the concave spigot cylindrical surface of the low-pressure turbine shaft as (x4, y4, z4). Project the measuring point data (x3, y3, z3) of the convex spigot cylindrical surface of the grate disc onto the fitting plane of the grate disc flange end face to obtain the mapping point cloud data (x5, y5, z5), projecting the low-pressure turbine shaft concave spigot cylindrical surface measurement point data (x4, y4, z4) onto the fitting plane of the low-pressure turbine shaft flange end face to obtain the mapping point cloud data (x6, y6, z6), and performing plane circle fitting on the mapping point cloud data (x5, y5, z5) and (x6, y6, z6) using the least squares method to obtain the spatial center O1 of the convex spigot cylindrical surface of the grate disc and the spatial center O2 of the concave spigot cylindrical surface of the low-pressure turbine shaft; Calculate the spatial angle θ2 between the line vector u connecting the spatial center of the convex spigot cylindrical surface of the grate disc and the spatial center of the low-pressure turbine shaft spigot cylindrical surface and the normal vector n of the fitting plane of the grate disc flange end face, and adjust the spatial angle to 0, that is, to achieve the concentricity of the spatial center of the concave spigot cylindrical surface of the low-pressure turbine shaft and the spatial center of the convex spigot cylindrical surface of the grate disc; The spatial angle θ2 between the line vector u connecting the center O1 of the convex spigot cylindrical surface of the grate disc and the center O2 of the concave spigot cylindrical surface of the low-pressure turbine shaft and the normal vector n of the fitting plane of the grate disc flange end face is calculated as follows: Where: θ2 is the spatial angle between the line vector connecting the center of the cylindrical surface of the convex spigot of the grate disc and the center of the cylindrical surface of the concave spigot of the low-pressure turbine shaft and the surface, unit: °; u is the line vector connecting the center of the cylindrical surface of the convex spigot of the grate disc O1 and the center of the cylindrical surface of the concave spigot of the low-pressure turbine shaft O2; n is the normal vector of the fitting plane of the end face of the grate disc flange; S4. Use an industrial camera equipped with a dual-view prism to photograph a pair of bolt holes on the end face of the grate disc flange and the end face of the low-pressure turbine shaft flange; Calculate the circumferential relative angle Δβ between a pair of bolt holes on the end face of the grate disc flange and the end face of the low-pressure turbine shaft flange. Adjust the circumferential relative angle to 0 to align the bolt holes on the end face of the low-pressure turbine shaft flange with the end face of the grate disc flange. The circumferential relative angle Δβ between a pair of bolt holes on the end face of the grate disc flange and the end face of the low-pressure turbine shaft flange is calculated as follows: Where: Δβ is the circumferential relative angle between the pair of bolt holes on the end face of the grate disc flange and the end face of the low-pressure turbine shaft flange, unit: °; D is the actual center distance between the pair of bolt holes on the end face of the grate disc flange and the end face of the low-pressure turbine shaft flange, unit: mm; R is the distance from the bolt holes on the end face of the grate disc flange and the end face of the low-pressure turbine shaft flange to the center of the circle, unit: mm; S5. Heat the low-pressure turbine shaft recess and monitor the temperature to ensure that the heating temperature reaches 350°C and the maximum temperature does not exceed 380°C. The holding time is 10 minutes. S6. Use an industrial camera to photograph the butt clearance between the low-pressure turbine shaft and the grate disc, calculate the butt clearance d between the low-pressure turbine shaft and the grate disc, and adjust the butt clearance to 0, thus achieving the spigot insertion action; S7. Monitor the collision force during the insertion of the stopper, and require that the collision force be less than the specified value to prevent damage to the workpiece and digital sensor caused by collision. If the collision force is normal, continue to insert the stopper until the butt joint surfaces are in contact; complete the butt joint assembly of the low-pressure turbine shaft and the grate disc.

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