A multi-point concentric assembly method and system for an engine rotor system

Abstract

The present invention discloses a multi-point concentric assembly method and system for an engine rotor system. The assembly method includes: determining the position of the engine fulcrum; determining the engine mounting stop datum; and determining the mounting stop form and position tolerance. The present invention aims to meet the minimum performance requirements allowed by the engine, and provides a maximum allowable eccentricity tolerance requirement for the engine's end fulcrum relative to the No. 1 fulcrum, taking into account conditions such as casing deformation and processing capabilities. Based on the maximum allowable eccentricity tolerance, a reasonable margin for eccentricity control requirements can be provided, further providing a reasonable design tolerance range. Based on the tolerance margin, a maximum allowable eccentricity tolerance that meets maintenance requirements can be further provided. By directly defining the relative positional relationship between two stops on the same component, the conversion of the component's internal datum and the accumulation of form and position tolerances are avoided, transmission links are reduced, and the optimal design is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of engines, and in particular relates to a multi-support point concentric assembly method and system for an engine rotor system. Background Art

[0002] The structure of aircraft engines is very complex, which brings many problems to the assembly of the whole machine. At the same time, the rotation accuracy of the rotor is very high. If you are not careful, it will cause vibration, performance degradation, rotor scratches, vibration instability of the power turbine long shaft, or fatigue fracture. Therefore, it is urgent to solve the following problems: reduce the concentric transmission links to ensure the concentricity of the engine assembly; control the form and position tolerances that affect concentricity; improve the quality of the whole machine assembly, reduce vibration, improve operational safety, ensure engine performance and life; and improve assembly efficiency.

[0003] In engine development, ensuring a reasonable pivot concentricity design plays a very important role in improving the assembly quality of the entire machine, reducing vibration, ensuring engine performance, and improving operational safety. According to the rotor support method, engine rotors can be divided into dual-pivot rotors and multi-pivot rotors. Among them, the multi-pivot rotor system has a large number of pivots and a relatively complex layout, which makes it difficult to design. The pivot concentricity is difficult to ensure, and the measurement is complex and difficult to implement. Existing engine design or assembly benchmarks are generally selected and measured in the following ways:

[0004] 1) Select the casing aperture of the outer ring of the engine main support bearing and its mounting end surface as the first reference;

[0005] 2) Use this benchmark to define the engine parts mounting casing stop and other supporting points, such as Figure 1 As shown;

[0006] 3) During the assembly process, the components are generally assembled from left to right (such as Figure 3 To ensure that the remaining main bearing fulcrums are concentric with the first datum, each time a component casing is assembled, the component (the semi-finished product of each assembly step of the entire machine) needs to be moved onto the three-dimensional coordinate measuring machine, the support hole of the component needs to be measured and adjusted, and then the component needs to be moved back to the assembly site to continue assembly until all the assembly is completed, which is time-consuming and labor-intensive.

[0007] The existing technical solutions have the following disadvantages:

[0008] The selected fulcrum aperture datum is usually in the center or inside of the receiver, which is not conducive to the selection of the measurement datum;

[0009] For multi-support benchmarks with large spans, whether the middle supports are concentric with the No. 1 support benchmark needs to be determined by measurement;

[0010] The design selection of the assembly non-concentricity error caused by the specific engine processing and casing deformation requires the probability statistics of a large number of samples over a long period of time;

[0011] Each time a casing is assembled, the parts (semi-finished products of each assembly step of the whole machine) need to be moved to the measuring instrument to measure and adjust the support holes of the parts, which is time-consuming and labor-intensive.

[0012] The positioning of multiple stoppers within each component and the reference of bearing assembly apertures are chaotic and inconsistent. Therefore, to solve this complex measurement and time-consuming and labor-intensive problem, it is urgent to develop a multi-point concentric assembly method for the engine rotor system. Summary of the Invention

[0013] In response to the above problems, the present invention discloses a multi-point concentric assembly method for an engine rotor system, comprising:

[0014] Determine the engine pivot point position;

[0015] Determine the engine installation spigot reference;

[0016] Determine the shape and position tolerances of the mounting spigot.

[0017] Furthermore, the engine support points include support point 1, support point 2, support point 3, support point 4, support point 5 and support point 6;

[0018] The No. 1 pivot and No. 2 pivot are installed in the air intake casing;

[0019] The No. 3 pivot point is installed in the compressor casing;

[0020] The No. 4 fulcrum is installed in the middle receiver;

[0021] The No. 5 fulcrum is installed in the power turbine casing;

[0022] The No. 6 fulcrum is installed in the exhaust casing.

[0023] Furthermore, the No. 1 pivot and No. 6 pivot are the main pivots of the power turbine rotor system;

[0024] The No. 2 fulcrum and No. 5 fulcrum are auxiliary fulcrums;

[0025] The No. 3 support point and the No. 4 support point are the main support points of the gas generator rotor system.

[0026] Furthermore, the engine includes an air intake component, a compressor component, a combustion chamber component, a power turbine rotor component, and an exhaust component;

[0027] The air intake component, the compressor component, the combustion chamber component, the power turbine rotor component and the exhaust component are connected in sequence through mounting spigots.

[0028] Furthermore, the specific steps of determining the engine mounting spigot reference are as follows:

[0029] Each engine component uses the first stop that is initially installed with other components as a reference to define the shape and position tolerances of another stop or the remaining stops.

[0030] Furthermore, the specific steps of determining the shape and position tolerance of the installation spigot are as follows:

[0031] Set the initial tolerance d0, the tolerance lower limit dj = 0, the calculation accuracy e0, the qualified performance index vector P0 = [p01, p02, ..., p0n], and the golden section parameter t = 0.618; where p0n is the nth qualified performance index;

[0032] Set the current tolerance di = d0, and calculate the length of the current tolerance segmentation interval b = di-dj;

[0033] Use the tolerance allocation method to allocate the current tolerance di to each assembly building block unit;

[0034] The engine is simulated and calculated for performance under the current tolerance state to obtain a current performance index vector Pi = [pi1, pi2, ..., pin]; wherein pin is the nth current performance index;

[0035] Calculate the difference between the current performance index vector and the qualified performance index vector a = [a1, a2, ..., an];

[0036] Determine whether at least one of a1, a2, ..., an is less than or equal to 0;

[0037] If yes, calculate the current tolerance segmentation interval length b = di-dj;

[0038] Determine whether b is less than or equal to e0;

[0039] If yes, record the current tolerance di.

[0040] Furthermore, after determining that at least one of a1, a2, ..., an is less than or equal to 0, the following steps are further included:

[0041] If not, set the lower limit of the tolerance value dj=di, and the current tolerance di increases by the set value as the step size.

[0042] Furthermore, after determining whether b is less than or equal to e0, the method further includes the following steps:

[0043] If not, the current tolerance di is set to decrease by the set value in steps.

[0044] Furthermore, the initial tolerance d0 is in the range of 0.5 to 1 mm;

[0045] The calculation accuracy e0 is in the range of 1×10 -3 ~1×10 -4 .

[0046] The present invention also discloses a multi-point concentric assembly system for an engine rotor system, comprising:

[0047] A fulcrum position unit, used to determine the engine fulcrum position;

[0048] Reference unit, used to determine the engine installation spigot reference;

[0049] Tolerance unit, used to determine the shape and position tolerance of the mounting spigot.

[0050] Compared with the prior art, the embodiments of the present invention have at least the following advantages:

[0051] 1) With the goal of meeting the minimum performance requirements of the engine, the maximum allowable eccentricity tolerance requirement for the engine end support relative to support No. 1 is given under conditions such as casing deformation and processing capabilities;

[0052] 2) Based on the maximum allowable eccentricity tolerance, a reasonable margin for eccentricity control requirements can be given, and further a reasonable design tolerance range can be given;

[0053] 3) Based on the tolerance margin, the maximum allowable eccentricity tolerance that meets maintenance requirements can be further given;

[0054] 4) By directly defining the relative position relationship between two stoppers on the same component, the conversion of internal datums and the accumulation of geometric tolerances can be avoided, the transfer links can be reduced, and the optimal design can be achieved;

[0055] 5) All engines designed in unit body can be designed and assembled according to this method. By controlling the transfer reference and concentric transfer route of each unit body component ("building block"), the concentricity of the fulcrum can be guaranteed to have a reasonable value range.

[0056] 6) Complete engine assembly efficiently and conveniently;

[0057] 7) Avoid instability or fatigue fracture of the power turbine long shaft;

[0058] 8) Ensure uniform clearance between compressor and turbine rotor and stator blades to improve engine performance;

[0059] 9) Control engine assembly quality;

[0060] 10) Provide measurement analysis and benchmarks for engine vibration, performance troubleshooting, etc.

[0061] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0063] Figure 1 A schematic diagram showing the existing concentric design requirements for No. 1 and No. 6 fulcrums is shown;

[0064] Figure 2 A schematic diagram of the layout of the engine rotor fulcrums according to an embodiment of the present invention is shown;

[0065] Figure 3 It shows a schematic diagram of the step-by-step installation and positioning of an engine casing according to an embodiment of the present invention;

[0066] Figure 4 A schematic diagram showing the offset of fulcrum No. 6 relative to fulcrum No. 1 according to an embodiment of the present invention is shown;

[0067] Figure 5 A flow chart showing the steps of coaxiality or circular runout tolerance design according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0068] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0069] The present invention provides a multi-point concentric assembly method for an engine rotor system, comprising the following steps:

[0070] Step S100: determining the engine fulcrum position;

[0071] The engine pivot points include pivot point 1, pivot point 2, pivot point 3, pivot point 4, pivot point 5 and pivot point 6;

[0072] The No. 1 pivot and No. 2 pivot are installed in the air intake casing;

[0073] The No. 3 pivot point is installed in the compressor casing;

[0074] The No. 4 fulcrum is installed in the middle receiver;

[0075] The No. 5 fulcrum is installed in the power turbine casing;

[0076] The No. 6 fulcrum is installed in the exhaust casing.

[0077] For the front output turboshaft engine, the general engine power turbine rotor system consists of a power turbine rotor and an output shaft assembly (or consists of a power turbine rotor end and an output shaft end in one piece), and is supported by four fulcrums. Two fulcrums are set on the rear extension section of the power turbine shaft, and two fulcrums are set on the power output shaft assembly. The layout is as follows: Figure 2 As shown in the figure, the front end of the power turbine rotor transmits the load to pivot point 1 via the output shaft assembly spline; pivot point 6 at the rear end is rigidly connected to the casing bracket; pivot point 2 is mounted on the rear of the output shaft casing via a spring-loaded support structure; pivot point 5 is mounted on the spring-loaded support. Therefore, pivot points 1 and 6 are the main pivot points of the power turbine rotor system, forming the rotor rotation center, while pivot points 2 and 5 are auxiliary pivot points.

[0078] Pivot No. 3 and Pivot No. 4 are the two main fulcrums of the gas generator rotor system and are the rotation centers of the gas generator rotor.

[0079] Pivot concentric installation requirements

[0080] like Figure 2 As shown in the figure, from the perspective of the transmission route, the span of the power turbine rotor fulcrum is large, and the concentricity involves many links, from the air intake casing, compressor casing, middle casing, power turbine casing, exhaust casing, to the power turbine bearing seat, spring support, etc. In order to reduce the adjustment links in the assembly, the positioning is carried out through the matching of the mounting stop of each casing and spring support to ensure the concentricity of the rotor fulcrum. That is, the installation of the above components adopts the installation of each component and casing step by step. The installation positioning ultimately determines the concentricity of the power turbine rotor system fulcrum. Figure 3 shown.

[0081] Seam design

[0082] In order to ensure the concentric design of the fulcrum and the coaxial force transmission route of the fulcrum, not only the installation coordination of each receiver and ammunition support is required to be reasonable, but also the reference and form and position tolerances of the mounting stop of each receiver and ammunition support need to be reasonably designed to reduce the influence of the transmission link and achieve the purpose of reducing radial deviation.

[0083] Step S200: determining the engine mounting spigot reference;

[0084] The two end portions of the sequentially installed components are set as stopper structures and set as the transfer reference for the assembly of the components (such as the intake components, compressor components, combustion chamber components, power turbine rotor components and exhaust components, etc., which are related to the assembly of the present invention);

[0085] The air intake component, the compressor component, the combustion chamber component, the power turbine rotor component and the exhaust component are connected in sequence through the mounting spigots;

[0086] Each engine component uses the first stop at which it is initially installed with other components as a reference to define the shape and position tolerance of the other stop. If a component has multiple stop locations, these stop locations (including the spring-loaded stop) should all be based on the first stop at which the component is initially installed, reducing conversion steps. If this is not possible in practice, the conversion reference of the other transfer reference should also minimize the error with the component's first reference to ensure high accuracy.

[0087] Step S300: Determine the shape and position tolerance of the installation stop.

[0088] As mentioned above, pivot points 1 and 6 constitute the rotor rotation center. Errors and eccentricity are inevitable during the processing and assembly process, such as Figure 4 To this end, the golden section method is used to design the transfer reference between components and the position tolerance of each fulcrum for offset, such as the coaxiality or circular runout tolerance of fulcrum No. 6 to fulcrum No. 1. The design steps are as follows, and the process is shown in Figure 5 .

[0089] Step S301: Start;

[0090] Step S302: Based on past experience, set the initial tolerance d0, the tolerance lower limit dj = 0, the calculation accuracy e0, the qualified performance index vector P0 = [p01, p02, ..., p0n], and the golden section parameter t = 0.618; where p0n is the nth qualified performance index;

[0091] Step S303: Set the current tolerance di = d0, and calculate the length of the current tolerance segmentation interval b = (di - dj);

[0092] Step S304: using a tolerance allocation method (such as the "extreme value method" or the "statistical square method") to allocate di to each assembly building block unit (i.e., each component);

[0093] Step S305: Performing a performance simulation calculation on the engine based on the current tolerance state to obtain a current performance index vector Pi = [pi1, pi2, ..., pin]; wherein pin is the nth current performance index;

[0094] Step S306: Calculate the difference a=[a1, a2, ..., an] between the current performance indicator vector and the qualified performance indicator vector; where an is the nth difference;

[0095] Step S307: Is a≤0 (i.e., determine whether at least one of a1, a2, ..., an is less than or equal to 0); if so, go to step S308; if not, set dj=di, di=di+b×t, and go to step S304;

[0096] Step S308: Calculate the current tolerance segmentation interval length b=(di-dj);

[0097] Step S309: Is b≤e0? If yes, go to step S311; if no, go to step S310;

[0098] Step S310: Set di = di - b × t, and go to step S304;

[0099] Step S311: Record the current tolerance di;

[0100] Step S312: End.

[0101] Among them, the initial tolerance d0 ranges from 0.5 to 1 mm;

[0102] The calculation precision e0 is in the range of 1×10 -3 ~1×10 -4 .

[0103] The final di calculated according to the above steps is the allowable tolerance value, which is the critical value between qualified and unqualified engine performance; when taking the actual value, appropriate margin should be left and the tolerance should be smaller.

[0104] If a calculated in step S306 is less than 0, it indicates that the performance does not meet the requirements, and the current tolerance di needs to be reduced in steps of b×t, that is, di=di-b×t; if it is greater than 0, it indicates that the performance meets the requirements, and the current tolerance di needs to be increased in steps of b×t, that is, di=di+b×t.

[0105] Among them, pi1, pi2, pi3, etc. in the current performance index vector are all parameters greater than zero, representing a series of performance requirements, such as engine power, fuel economy (=1 / fuel consumption rate), vibration index (=1 / total vibration), casing strength index (=1 / maximum casing stress) and stiffness index (=1 / maximum casing displacement). When using simulation methods to calculate these parameters, the influence of part deformation should be considered;

[0106] Allocate the di tolerance to each assembly building block unit, including the tolerance of the casing stop of each component; each component is further allocated from the stop to the casing stop, bearing mounting hole and end face within the component;

[0107] The calculation accuracy e0 can also be the measurement accuracy.

[0108] Installation of spigot fit control

[0109] The hole-shaft fit of the mounting spigots located along the concentricity transmission path should be a tight fit, i.e., an interference fit, transition fit, or small clearance fit, to ensure the concentricity of the assembly between the receiver (or support). This also reduces the concentricity error caused by wear due to repeated assembly. Clearance fit has an adverse effect on the concentricity of the assembly support point and is the key control object in the design. The misalignment caused by excessive clearance should be avoided.

[0110] The fit of the installation stop should take into account the temperature influence of the working conditions of the selected material to ensure that the gap changes caused by thermal expansion and contraction at high and low temperatures do not affect the reliable fit of the two casing stop positioning, that is, the fit that was originally an interference fit in the cold state should still remain a tight fit at high temperatures.

[0111] Based on the above-mentioned multi-point concentric assembly method of the engine rotor system, this embodiment provides a multi-point concentric assembly system of the engine rotor system, comprising:

[0112] A fulcrum position unit, used to determine the engine fulcrum position;

[0113] Reference unit, used to determine the engine installation spigot reference;

[0114] Tolerance unit, used to determine the shape and position tolerance of the mounting spigot.

[0115] Benchmark unit, specifically used for:

[0116] Each engine component uses the first stop that is initially installed with other components as a reference to define the shape and position tolerances of another stop or the remaining stops.

[0117] The present invention proposes a multi-point concentric assembly method and system for an engine rotor system, which aims to meet the minimum performance requirements allowed by the engine, and gives the maximum allowable eccentricity tolerance requirement of the engine end support to the No. 1 support under conditions such as casing deformation and processing capacity; based on the maximum allowable eccentricity tolerance, a reasonable margin for eccentricity control requirements can be given, and a reasonable design tolerance range can be further given; based on the tolerance margin, a maximum allowable eccentricity tolerance that meets maintenance requirements can be further given; by directly defining the relative position relationship between the two stoppers on the same component, the conversion of the internal datum of the component and the accumulation of form and position tolerances are avoided, the transmission links are reduced, and the optimal design is achieved; engines designed as unit bodies can be designed and assembled according to this method, and by controlling the transmission datum and concentric transmission route of each unit body component ("building block") itself, a reasonable range of fulcrum concentricity values ​​is guaranteed.

[0118] Although the present invention 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; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-point concentric assembly method for an engine rotor system, characterized in that: include: Determine the engine pivot point position; Determine the engine installation spigot reference; Determine the shape and position tolerance of the installation spigot; The specific steps for determining the engine mounting spigot reference are as follows: Each engine component uses the first stop that is initially installed with other components as a reference to define the shape and position tolerance of the other stop or the remaining stops; The engine pivot points include pivot point 1, pivot point 2, pivot point 3, pivot point 4, pivot point 5 and pivot point 6; The No. 1 pivot and No. 2 pivot are installed in the air intake casing; The No. 3 pivot point is installed in the compressor casing; The No. 4 fulcrum is installed in the middle receiver; The No. 5 fulcrum is installed in the power turbine casing; The No. 6 pivot point is installed in the exhaust casing; The specific steps for determining the shape and position tolerance of the installation spigot are as follows: Set the initial tolerance d0, the lower limit of the tolerance dj = 0, the calculation accuracy e0, the qualified performance index vector P0 = [p01, p02, ..., p0n], and the golden section parameter t = 0.618; where p0n is the nth qualified performance index; Set the current tolerance di=d0 and calculate the length of the current tolerance segmentation interval b=di-dj; Use the tolerance allocation method to allocate the current tolerance di to each assembly building block unit; The engine performance is simulated and calculated based on the current tolerance state to obtain the current performance index vector Pi = [pi1, pi2, ..., pin]; where pin is the nth current performance index; Calculate the difference a=[a1, a2, ..., an] between the current performance index vector and the qualified performance index vector; Determine whether at least one of a1, a2, ..., an is less than or equal to 0; If yes, calculate the current tolerance segmentation interval length b=di-dj; Determine whether b is less than or equal to e0; If yes, record the current tolerance di.

2. The multi-point concentric assembly method of an engine rotor system according to claim 1, characterized in that: The No. 1 pivot point and No. 6 pivot point are the main pivot points of the power turbine rotor system; The No. 2 fulcrum and No. 5 fulcrum are auxiliary fulcrums; The No. 3 support point and the No. 4 support point are the main support points of the gas generator rotor system.

3. The multi-point concentric assembly method of an engine rotor system according to claim 1, characterized in that: The engine includes an air intake component, a compressor component, a combustion chamber component, a power turbine rotor component and an exhaust component; The air intake component, the compressor component, the combustion chamber component, the power turbine rotor component and the exhaust component are connected in sequence through mounting spigots.

4. The multi-point concentric assembly method of an engine rotor system according to claim 1, characterized in that: After determining that at least one of a1, a2, ..., an is less than or equal to 0, the following steps are further included: If not, set the lower limit of the tolerance value dj=di, and the current tolerance di increases by the set value as the step size.

5. The multi-point concentric assembly method of an engine rotor system according to claim 1, characterized in that: After determining whether b is less than or equal to e0, the following steps are further included: If not, the current tolerance di is set to decrease by the set value in steps.

6. The multi-point concentric assembly method of an engine rotor system according to claim 1, characterized in that: The initial tolerance d0 ranges from 0.5 to 1 mm; The calculation accuracy e0 is in the range of 1×10 -3 ~ 1×10 -4 .

7. A multi-point concentric assembly system for an engine rotor system, characterized in that: include: A fulcrum position unit, used to determine the engine fulcrum position; Reference unit, used to determine the engine installation spigot reference; Tolerance unit, used to determine the shape and position tolerance of the installation spigot; The specific steps for determining the engine mounting spigot reference are as follows: Each engine component uses the first stop that is initially installed with other components as a reference to define the shape and position tolerance of the other stop or the remaining stops; The engine pivot points include pivot point 1, pivot point 2, pivot point 3, pivot point 4, pivot point 5 and pivot point 6; The No. 1 pivot and No. 2 pivot are installed in the air intake casing; The No. 3 pivot point is installed in the compressor casing; The No. 4 fulcrum is installed in the middle receiver; The No. 5 fulcrum is installed in the power turbine casing; The No. 6 pivot point is installed in the exhaust casing; The specific steps for determining the shape and position tolerance of the installation spigot are as follows: Set the initial tolerance d0, the lower limit of the tolerance dj = 0, the calculation accuracy e0, the qualified performance index vector P0 = [p01, p02, ..., p0n], and the golden section parameter t = 0.618; where p0n is the nth qualified performance index; Set the current tolerance di=d0 and calculate the length of the current tolerance segmentation interval b=di-dj; Use the tolerance allocation method to allocate the current tolerance di to each assembly building block unit; The engine performance is simulated and calculated based on the current tolerance state to obtain the current performance index vector Pi = [pi1, pi2, ..., pin]; where pin is the nth current performance index; Calculate the difference a=[a1, a2, ..., an] between the current performance index vector and the qualified performance index vector; Determine whether at least one of a1, a2, ..., an is less than or equal to 0; If yes, calculate the current tolerance segmentation interval length b=di-dj; Determine whether b is less than or equal to e0; If yes, record the current tolerance di.

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