A two-stage torque loading spindle strength test device

Abstract

The present application belongs to the field of aero-engine testing, and in particular relates to a two-stage torque-loaded main shaft strength test device. According to the load characteristics of the shaft test piece, the two-stage rotor main shaft strength test load is simplified, and a two-stage torque-loaded main shaft strength test scheme is designed. Through structural innovations such as fulcrum components and bending moment loading components, the difficulty of reasonable design of complex load paths in limited spaces is overcome, and two-stage torque loading of superimposed axial force and bending moment loads in the main shaft strength test is realized.

Description

Technical Field

[0001] The present application belongs to the field of aero-engine testing, and in particular relates to a two-stage torque-loaded spindle strength testing device. Background Art

[0002] The main shaft, including the low-pressure turbine shaft and high-pressure turbine shaft, is the core transmission component of the aircraft engine and must be subjected to strength assessment. The loads borne by the main shaft of the aircraft engine include torque (vibration torque), axial force and bending moment load. The low-pressure turbine rotor system of a certain type of aircraft engine has a complex structure. A two-stage rotor with a total of four turbine disks is installed on the low-pressure turbine shaft, which increases the number of test loads and the complexity of the device structure by several times. The difficulty lies in designing a reasonable test method and device structure.

[0003] At present, there is no strength test method and device for this type of main shaft equipped with a dual-rotor structure. The existing technology is for the strength test of the main shaft of a single-rotor structure. The torque load is applied through the sleeve gear end, through the force multiplication arm method or through a torque machine, and the other end acts on the rotor mounting edge through an anti-torsion spring or actuator to bear the torque; the axial force is applied through an external actuator, one end acts on the shaft end nut, and the other end acts on the rotor mounting edge; the bending moment is applied to the shaft end through the lateral force multiplication arm method or the eccentric cam method, and there is also a force couple method to load the rotor mounting edge and the shaft end. The existing technical solution is for the strength test of the main shaft installed with a single rotor structure, which cannot meet the strength test requirements of the dual-rotor structure of the low-pressure turbine shaft of this type of engine. In terms of torque, single-end torsion and torsion bearing can apply equal torque on the shaft, but cannot load double-stage torque; in terms of bending moment, the method of lateral force multiplied by the lever arm is more suitable for the situation where the test point is close to the fulcrum. If the span between the test point and the fulcrum is large, loading in this way will cause the bending moment load near the fulcrum to be too large, resulting in an unreasonable load form; the eccentric cam method is similar to the lateral force multiplied by the lever arm method, except that it is not applicable to large spans. Because it is driven by a motor, it will also bring about the problem of difficulty in synchronizing the torque and axial force of the servo control throughout the fatigue test; and the use of a couple pair method to load the bending moment will make the bending moment within the loading range equal, which may also cause overload of non-test parts. Summary of the invention

[0004] In order to solve the above problems, the present application provides a two-stage torque loading main shaft strength test device, which performs torque, bending moment and axial force load tests on the low-pressure turbine shaft, including:

[0005] A rear end support assembly and a front end support assembly respectively serving to fix and support the rear end and the front end of the low-pressure turbine shaft;

[0006] A first torque loading device for applying a first torque to the low-pressure turbine shaft and a second torque loading device for applying a second torque;

[0007] The rear end pivot assembly is generally disc-shaped, and includes an outer ring and an inner ring, the outer ring and the inner ring are connected by a bearing, the center of the inner ring is fixedly connected to the low-pressure turbine shaft, the inner ring has circumferentially arranged through holes, and the outer ring is fixedly connected to the test bench;

[0008] The first torque loading device is in a cylindrical shape, one end of which is fixed on the test bench, and the other end is fixed on the low-pressure turbine shaft through the through hole of the inner ring via a fulcrum adapter cylinder, and the wall surface of the fulcrum adapter cylinder is in a grid shape;

[0009] The second torque loading

[0010] The device includes a pair of torque loading units which are parallel to each other and not in the same straight line, a torque sensor which is sleeved on the outside of the low-pressure turbine shaft, a torque adding arm which connects the torque loading unit and the torque sensor, and a simulated rotor assembly which fixes the torque sensor to the low-pressure turbine shaft; wherein the torque adding arm and the torque loading unit are perpendicular to the low-pressure turbine shaft, the simulated rotor assembly is also connected to a moment loading unit which is parallel to the low-pressure turbine shaft, the moment loading unit passes through the torque adding arm, and a moment bearing assembly which is perpendicular to the low-pressure turbine shaft is fixed at the end of the torque adding arm, and the moment bearing assembly is fixed to the test bench.

[0011] Preferably, there are two bending moment loading units, which are symmetrically arranged along the center line of the low-pressure turbine shaft.

[0012] Preferably, the first torque loading device includes a pair of torque loading units that are parallel to each other and not in the same straight line, a torque adding arm connected to the torque loading unit, a torque sensor fixedly connected to the torque adding arm, a shaft torsion connecting plate connected to the torque sensor, a shaft torsion connecting tube connected to the shaft torsion connecting plate, the shaft torsion connecting tube being connected to a fulcrum adapter tube, and the fulcrum adapter tube being fixedly connected to the low-pressure turbine shaft through a simulated short shaft.

[0013] Preferably, the outer ring of the rear end fulcrum assembly is an outer bearing mounting seat connected to the bearing, and the inner ring includes: an inner bearing mounting seat connected to the inner ring of the bearing, a connecting plate connected between the inner bearing mounting seat and the low-pressure turbine shaft, the connecting plate includes an upper connecting plate and a lower connecting plate, the upper connecting plate and the lower connecting plate bite the low-pressure turbine shaft and the inner bearing mounting seat to fix the low-pressure turbine shaft and the inner bearing mounting seat, and the upper connecting plate and the lower connecting plate are arranged circumferentially to form the through hole.

[0014] Preferably, the moment bearing assembly comprises two parallel lower bearing plates and two upper bearing plates fixed on the lower bearing plates, the upper bearing plates having U-shaped grooves, and the U-shaped grooves are arranged along the circumference.

[0015] Preferably, the torque sensor is in the shape of a hollow cylinder with a central hole, with flange edges at the upper and lower ends, and with stoppers formed by bosses at the upper and lower end surfaces.

[0016] The advantages of the present application include: 1. Realizing a dual torque load test; 2. Simplifying the bending moment loading scheme. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is the parts diagram of the low-pressure turbine shaft;

[0018] Figure 2 It is the assembly drawing of the low-pressure turbine shaft;

[0019] Figure 3 Schematic diagram of the dual-stage torque loading spindle strength test device;

[0020] Figure 4 It is the torque sensor parts diagram;

[0021] Figure 5 is a cross-sectional view of the rear end pivot assembly;

[0022] Figure 6 It is a K-direction schematic diagram of the rear-end fulcrum assembly;

[0023] Figure 7 is a schematic diagram of the moment loading unit;

[0024] Figure 8 is a schematic diagram of a moment bearing assembly;

[0025] Fig. 9 It is a schematic diagram of the moment lateral force loading form;

[0026] Fig.10 It is a schematic diagram of the loading form of the bending moment couple;

[0027] Fig.11 It is a schematic diagram of the loading form of a single force couple;

[0028] Among them, 1-bearing column; 2-rear end support bearing plate; 3-torque bearing unit; 4-first torque loading unit; 5-first torque adding arm; 6-torque sensor; 7-axis torsion plate; 8-axis torsion connecting tube; 9-axial force loading unit; 10-rear end support assembly; 11-support adapter tube; 12-simulated short shaft; 13-simulated rotor assembly; 14-torque sensor; 15-second torque loading unit; 16-second torque adding arm; 17-low-pressure turbine shaft test piece; 18-bending moment loading unit; 19-front end support assembly; 20-bending moment bearing assembly; 21-simulated low-pressure compressor shaft; 22-simulated bushing; 23-torsion plate; 101-rear end support bearing plate; 102-bearing outer mounting seat; 10 3-bearing; 104-upper connecting plate; 105-bearing inner mounting seat; 106-lower connecting plate; 107-shaft test piece; 108-fulcrum adapter tube; 109-simulated inner ring; 182-connecting ear seat; 183-column; 184-servo actuator; 186-force sensor; 141-flange edge; 142-elastic section; 143-bolt hole; 144-stop; 145-middle hole; 171-front spline; 172-front internal thread; 173-bending moment test section A; 174-rotor mounting edge; 175-rear spline; 176-rear external thread; 187-adapter; 208-lower bearing plate; 209-upper bearing plate; 2010-bolt mounting hole; 2011-U-shaped groove. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical scheme and advantages of the implementation of this application clearer, the technical scheme in the implementation of this application will be described in more detail in combination with the drawings in the implementation of this application. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described implementation is a part of the implementation of this application, not all of the implementations. The implementation described below with reference to the drawings is exemplary and is intended to be used to explain this application, and cannot be understood as a limitation on this application. Based on the implementation in this application, all other implementations obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The implementation of this application is described in detail below in combination with the drawings.

[0030] The schematic diagram of the low-pressure turbine shaft structure of a certain type of aircraft engine is as follows Figure 1 As shown, it is a hollow shaft structure.

[0031] The outer side of the front end of the low-pressure turbine shaft is connected to the low-pressure compressor shaft through the front spline to transmit the torque generated by the turbine rotor to the compressor end. The inner side is connected to the bushing through the internal thread to transmit the axial force. The front low-pressure turbine rotor is installed on the rotor mounting edge of the low-pressure turbine shaft through a pin shaft, and the rear low-pressure turbine rotor is installed on the rotor mounting edge of the short shaft through a pin shaft. The short shaft is connected to the low-pressure turbine shaft through a spline. The turbine rotor generates torque, bending moment and axial force loads. The front and rear fulcrums are both composed of cylindrical roller bearings and bearing seats, which are used to radially constrain and support the low-pressure turbine shaft.

[0032] Original test load:

[0033] a) Torque load: Aerodynamic force acts on the two-stage low-pressure turbine rotor, each generating a torque load M 扭1 、M 扭2 , the direction is the same along the axis, acting on the rotor mounting edges of the low-pressure turbine shaft and the short shaft respectively;

[0034] b) Axial force load: Axial force loads F1 and F2 are also generated by aerodynamic force, and the action position is the same as above, generating tensile loads on the shaft;

[0035] c) Bending moment load: The bending moment load M is mainly generated by the gyroscopic moment of the two-stage low-pressure turbine rotor. 弯1 、M 弯2 , the direction is perpendicular to the axis, and the test position is Figure 1 Middle A section;

[0036] The test device for the low-pressure turbine shaft of the present application is as follows Figure 3 As shown, the low-pressure turbine shaft test piece 17 is fixed on the bearing column 1 through the front-end fulcrum assembly 19, the rear-end fulcrum assembly 10, and the rear-end fulcrum bearing plate 2. The front-end fulcrum assembly 19 is composed of a cylindrical roller bearing, a bearing seat and corresponding fixing fixtures; the rear-end fulcrum assembly 10 is composed of a deep groove ball bearing, a bearing seat and corresponding supporting fixtures.

[0037] The front torque loading device is composed of a second torque loading unit (15), a second torque adding arm 16, a torque sensor 14 and a simulated rotor assembly 13, etc., and is installed on the turbine rotor mounting edge of the low-pressure turbine shaft test piece 17 to apply the front torque load; the rear torque loading device includes a first torque loading unit 4, a first torque adding arm 5, a torque sensor 6, a shaft torsion plate 7, a shaft torsion connecting tube 8 and a fulcrum adapter tube 11, which is connected to the rear spline of the low-pressure turbine shaft test piece 17 through a simulated short shaft 12 to apply the rear torque load. The torque bearing device is composed of a torque bearing unit 3, a torsion plate 23 and a simulated low-pressure compressor shaft 21, which is connected to the front spline of the low-pressure turbine shaft test piece 17 and fixed on the bearing column 1.

[0038] The axial force loading unit 9 is used to apply axial force load, and is composed of a servo actuator, a force sensor, a loading rod and other tools. One end is installed on the shaft torsion plate 7, and the other end is connected to the front end thread of the low-pressure turbine shaft test piece 17 through a simulated bushing 22 to achieve internal force balance when the axial force load is applied.

[0039] The distributed moment loading unit 18 is used to apply a moment load in the form of a single couple, one end of which is mounted on the simulated rotor assembly 13 , and the other end of which is fixed to the bearing column 1 through a moment bearing assembly 20 .

[0040] In the test, multiple loads are loaded in a coordinated manner, and closed-loop control of the load is achieved by servo actuators, sensors (force and torque), and controllers.

[0041] The large-aperture double-flange torque sensor in the test device is a newly designed large-aperture double-flange torque sensor adapted to the tester structure. Figure 4 As shown in the figure, the main structural features are: the center hole can be sleeved outside the low-pressure turbine shaft, leaving deformation space; the axial dimension is as short as possible, and on the basis of the double-sided flange edges meeting the strength requirements, Figure 4 The G dimension is designed as the limit dimension that can be loaded with bolts on both sides; because the torque is carried by the bolts, the bolt size, quantity and strength grade need to be designed according to the load; the two sides are designed with stoppers for positioning. The key dimensions of the 50,000 Nm torque sensor designed according to the above principles are: φA: 350; φB: 290; φD: 200; H: 25; F: 150; I: 5; unit: mm. The specifications and quantity of the connecting bolts are: M20, grade 12.9, 16 evenly distributed.

[0042] b) Rotatable fulcrum assembly

[0043] In order to avoid interference between the fulcrum adapter tube and the rear fulcrum assembly during torsional deformation, this project designed a rotatable fulcrum assembly with the following structure: Figure 5 and Figure 6 As shown in the figure, the key points of the structure are as follows: the external bearing is adopted to move the rotating surface outward. The simulated inner ring 109 is fixed on the shaft test piece 107, and the fulcrum adapter tube 108 is sleeved on the outside of the shaft test piece 107. The openings are evenly distributed in the axial direction, and the upper connecting plate 104 and the lower connecting plate 106 are installed. The inner side of the bearing 103 is connected to the upper connecting plate 104 and the lower connecting plate 106 through the bearing inner mounting seat 105, and the outer side is installed on the rear end fulcrum bearing plate 101 through the bearing outer mounting seat 102. The connection between the upper connecting plate 104, the lower connecting plate 106 and the simulated inner ring 109 adopts a hook structure to improve the moment bearing capacity.

[0044] c) Single-couple moment loading device

[0045] In order to apply the moment load more reasonably, this project designed a single-couple moment loading device with the following structure: Figure 7As shown, the moment loading unit is composed of a servo actuator 184, a force sensor 186 and a transfer fixture 187, and is controlled by an external controller. The loading units in this project are all of this type. The front and rear ends of the moment loading unit are connected to the upper bearing plate 209 and the simulated rotor assembly 13 through connecting single ears, respectively. The simulated rotor assembly 13 is connected to the rotor mounting edge of the shaft test piece. The two upper bearing plates 209 are connected to the two lower bearing plates 208 by bolts to form a hollow moment bearing structure, as shown in FIG. Figure 7 As shown, it is fixed on the column 183. During the test, the two actuators on both sides apply loads in opposite directions to form a force couple, so as to apply a bending moment load to the shaft test piece. The U-shaped groove 2011 of the upper bearing plate 209 in the bending moment bearing structure is used to adjust the position of the loading actuator. The same structure is also designed on the simulated rotor assembly 13, which is convenient for the arrangement of multiple actuators when a rotational bending load needs to be applied; to ensure that the test results are true and valid, the test boundary conditions should simulate the actual state of the engine as much as possible. The positions of the front and rear fulcrums need to be designed according to the engine size. On the engine, the axial direction of the low-pressure turbine shaft can be positioned by the front and rear components, but the corresponding components are missing under the test conditions, so the rear end fulcrum is changed to a deep groove ball bearing for axial positioning and bearing the deadweight of the device.

[0046] Design of loading scheme for each test load:

[0047] Torque load: Torque is the most important load in shaft strength test. In order to obtain the real test results, it is necessary to design a two-stage torque loading device according to its structural characteristics to load M 扭1 、M 扭2 ; Force transmission path: Torque loads are applied to the two-stage low-pressure turbine rotors respectively. The load-bearing end simulates the low-pressure compressor shaft with reference to the engine structure design, and the torque is transmitted through the splines.

[0048] There are two prominent design difficulties in two-stage torque loading:

[0049] a) Apply torque to the middle section of the test piece. In the case of small deformation, the force and lever arm loading form can be used to directly apply force load, but due to the large torsional deformation in this test, the lever arm will change and it is impossible to apply accurate torque load. Therefore, a torque sensor is used in this project to directly measure torque, which requires the torque sensor to be assembled outside the shaft. Due to the large outer diameter of the shaft, there is no suitable torque sensor available on the market, so this project has designed a new torque sensor. The structure is detailed in Figure 4 ;

[0050] b) Torsional interference problem of the fulcrum. Due to size and space limitations, the torque load of the rear low-pressure turbine rotor can only be loaded at the rear end of the shaft and applied to the test piece through tooling such as the adapter cylinder. Since the axial direction passes through the rear end fulcrum, the adapter cylinder needs to have an opening on the side for the fulcrum assembly to pass through. If the fulcrum assembly is designed according to the conventional structure, that is, the bearing is installed on the shaft and the bearing seat adopts a fixed support, when the torque is loaded, the torsional deformation of the test piece drives the circumferential rotation of the adapter cylinder, which will contact the fulcrum assembly, resulting in failure to load. For this reason, this project innovatively designed a rotatable fulcrum assembly;

[0051] Simplification of axial force and bending moment loads: Ideally, axial force and bending moment loads should also be applied in stages. However, due to space limitations, a two-stage design for all three loads would make the device structure too large and complex to implement, which is not conducive to test stability and cost control. Therefore, in this solution, the axial force (F 合 = F1 + F2) is applied to the rear turbine rotor, resulting in a combined bending moment (M 弯合 =M 弯1 +M 弯2 ) is applied to the front turbine rotor. After calculation, the load distribution according to this scheme still meets the test assessment requirements.

[0052] Axial force loading scheme: Due to the hollow structure, the axial force loading device can be designed to be fixed on the rear turbine rotor through a loading unit at one end, and the other end can act on the simulated bushing with an internal push rod structure to achieve axial force loading on the entire test piece;

[0053] Bending moment load loading scheme: The bending moment test position is Figure 1 For the middle A section, there are two previous methods of moment loading: Fig. 9 The figure shows the lateral force loading method. The loading point is the spline at the front end of the shaft. The loading method is simple, but due to the large span, the loading position is far away from the moment test section. From the moment diagram, it can be seen that this method will cause the moment load of the front section of section A to be too large. Fig.10 The figure shows a couple loading method. The advantage is that the two ends of the loading device can be placed on the turbine rotor end and the torsion bearing device end respectively, so as to achieve the internal force balance of the axial force and simplify the structure. However, it can be seen from the bending moment diagram that this method makes the front bending moment of the turbine rotor a constant value and the rear bending moment zero. Since the actual engine bending moment comes from the turbine rotor, it can be seen that this bending moment method is still quite different from the actual one. Fig.11 The figure shows the single-couple loading method adopted in this scheme. From the bending moment diagram, it can be seen that this scheme is closest to the actual load of the engine.

[0054] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A two-stage torque loading main shaft strength test device, which performs torque, bending moment and axial force load tests on a low-pressure turbine shaft (17), wherein the low-pressure turbine shaft (17) has a rotor mounting edge (174) that bears a first torque and a rear end spline (175) that bears a second torque; It is characterized in that include: A rear end support assembly (10) and a front end support assembly (19) for respectively fixing and supporting the rear end and the front end of the low-pressure turbine shaft (17); A first torque loading device for applying a first torque to a low-pressure turbine shaft (17) and a second torque loading device for applying a second torque; The rear end fulcrum assembly (10) is generally disc-shaped and comprises an outer ring and an inner ring, the outer ring and the inner ring are connected by a bearing (103), the center of the inner ring is fixedly connected to the low-pressure turbine shaft (17), the inner ring has circumferentially arranged through holes, and the outer ring is fixedly connected to the test bench; The first torque loading device is in the shape of a cylinder, one end of which is fixed on the test bench, and the other end of which is fixed on the low-pressure turbine shaft (17) through the through hole of the inner ring via a fulcrum adapter cylinder (11), and the wall surface of the fulcrum adapter cylinder (11) is in the shape of a grid; The second torque loading device comprises a pair of second torque loading units (15) which are parallel to each other and not in the same straight line, a torque sensor (14) sleeved on the outside of a low-pressure turbine shaft (17), a second torque adding arm (16) connecting the second torque loading unit (15) and the torque sensor (14), and a simulated rotor assembly (13) which fixedly connects the torque sensor (14) and the low-pressure turbine shaft (17); wherein the second torque adding arm (16) and the second torque loading unit (15) are perpendicular to the low-pressure turbine shaft (17), the simulated rotor assembly (13) is further connected to a bending moment loading unit (18) which is parallel to the low-pressure turbine shaft (17), the bending moment loading unit (18) passes through the second torque adding arm (16), the end of which is fixed with a bending moment bearing assembly (20) which is perpendicular to the low-pressure turbine shaft (17), and the bending moment bearing assembly (20) is fixed to the test bench.

2. The two-stage torque loading spindle strength test device according to claim 1 is characterized in that: There are two bending moment loading units (18), which are symmetrically arranged along the center line of the low-pressure turbine shaft (17).

3. The two-stage torque loading spindle strength testing device according to claim 1 is characterized in that: The first torque loading device comprises a pair of first torque loading units (4) which are parallel to each other and not in the same straight line, a first torque applying arm (5) connected to the first torque loading unit (4), an axis torsion connecting tube (8) fixedly connected to the first torque applying arm (5), the axis torsion connecting tube (8) being connected to a fulcrum adapter tube (11), and the fulcrum adapter tube (11) being fixedly connected to a low-pressure turbine shaft (17) via a simulated short shaft (12).

4. The two-stage torque loading spindle strength testing device according to claim 1, characterized in that: The outer ring of the rear end fulcrum assembly (10) is a bearing outer mounting seat (102) connected to the bearing (103), and the inner ring comprises: a bearing inner mounting seat (105) connected to the inner ring of the bearing (103), a connecting plate connected between the bearing inner mounting seat (105) and the low-pressure turbine shaft (17), the connecting plate comprising an upper connecting plate (104) and a lower connecting plate (106), the upper connecting plate (104) and the lower connecting plate (106) engaging with the bearing inner mounting seat (105), and the upper connecting plate (104) and the lower connecting plate (106) are arranged in a circumferential direction to form the through hole.

5. The two-stage torque loading spindle strength testing device according to claim 1, characterized in that: The moment bearing assembly (20) comprises two parallel lower bearing plates (208) and two symmetrically mounted upper bearing plates (209) fixed on the lower bearing plates (208); the upper bearing plates (209) have U-shaped grooves (2011) arranged along a circumference.

6. The two-stage torque loading spindle strength testing device according to claim 1, characterized in that: The torque sensor (14) is in the shape of a hollow cylinder with a central hole (145), and has flange edges (141) at its upper and lower ends, and stoppers (144) formed by bosses at its upper and lower end surfaces.

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