A test device for elastic-supported dry friction damper

Abstract

The present invention provides a test device for an elastic dry friction damper, which relates to the field of damper testing technology. The damper includes an elastic support, a static friction plate, and a dynamic friction plate. The elastic support includes an inner ring, an outer ring, and an elastic element located in the annular space between the inner ring and the outer ring. The dynamic friction plate is provided on one end face of the inner ring. The test device includes a multi-degree-of-freedom motion platform, a displacement measuring device, and two sets of constraint devices arranged orthogonally around the outer ring. Each set of constraint devices includes two constraint devices, and the two constraint devices of the same set respectively abut against opposite sides of the outer ring. The elastic support retains one axial degree of freedom through the two sets of constraint devices. The two sets of constraint devices are also used to obtain the force applied to the elastic support. The static friction plate is provided on the multi-degree-of-freedom motion platform, and the dynamic friction plate abuts against the static friction plate. The displacement measuring device is used to obtain the displacement of the dynamic friction plate. The test device can perform component-level testing on the elastic dry friction damper.

Description

Technical Field

[0001] The present invention relates to the technical field of damper testing, in particular to a test device for a spring-supported dry friction damper. Background Art

[0002] In aircraft engine rotor systems, elastically supported friction dampers are used for vibration reduction and suppression due to their simple structure and ease of active control. The dynamic characteristics of elastically supported friction dampers are nonlinear and depend on the clamping force, vibration level, and relative motion trajectory.

[0003] To reveal the vibration reduction mechanism of elastic-braced friction dampers under complex motion conditions and provide a basis for their design in aircraft engine rotor systems, prior art has directly applied the elastic-braced friction dampers to the rotor and conducted dynamic characteristic tests on the entire engine together with the rotor, making it difficult to conduct component-level testing on the elastic-braced friction dampers alone. Summary of the Invention

[0004] The object of the present invention is to provide a test device for a spring-supported dry friction damper to solve the technical problem that it is difficult to perform component-level testing on the spring-supported dry friction damper.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a test device for an elastic support friction damper, wherein the damper comprises an elastic support, a static friction plate, and a dynamic friction plate. The elastic support comprises an inner ring, an outer ring, and an elastic element located in an annular space between the inner ring and the outer ring. The dynamic friction plate is provided on one end surface of the inner ring.

[0007] The test device includes a multi-degree-of-freedom motion platform, a displacement measuring device, and two sets of constraint devices arranged orthogonally around the periphery of the outer ring, each set of constraint devices includes two constraint devices, and the two constraint devices in the same set are respectively abutted against opposite sides of the outer ring; the elastic support retains one axial degree of freedom through the two sets of constraint devices; the two sets of constraint devices are used to obtain the force applied to the elastic support;

[0008] The static friction plate is arranged on the multi-degree-of-freedom motion platform, and the dynamic friction plate abuts against the static friction plate;

[0009] The displacement measuring device is used to obtain the displacement of the dynamic friction plate.

[0010] According to at least one embodiment of the present invention, the restraint device includes a base and a universal ball connected to the base, wherein the universal ball abuts against the outer ring;

[0011] In the same group of the constraint devices, one of the constraint devices includes at least one universal ball, and the other constraint device includes at least two universal balls.

[0012] According to at least one embodiment of the present invention, each group of the constraint devices includes two force sensors, one of the force sensors is arranged between the base of one of the constraint devices and the at least one universal ball, and the other force sensor is arranged between the base of another of the constraint devices and the at least two universal balls.

[0013] According to at least one embodiment of the present invention, in the same group of the constraint devices, one of the constraint devices includes one universal ball, and the other constraint device includes two universal balls. The center line connecting the three universal balls is an isosceles triangle, and the plane where the isosceles triangle is located is perpendicular to the axial direction of the elastic support.

[0014] According to at least one embodiment of the present invention, the restraint device also includes a linear motion mechanism arranged on the base, the universal ball and the force sensor are both connected to the movable end of the linear motion mechanism, and the universal ball applies a preload force on the outer ring through the linear motion mechanism.

[0015] According to at least one embodiment of the present invention, the test device further comprises a pressure regulating device, wherein the pressure regulating device is used to regulate the pressure between the dynamic friction plate and the static friction plate.

[0016] According to at least one embodiment of the present invention, the pressure regulating device includes a bracket, a pulley, a first rope and a first counterweight, the pulley is rotatably arranged on the bracket, one end of the first rope is connected to the elastic support, and the other end passes around the pulley and is connected to the first counterweight.

[0017] According to at least one embodiment of the present invention, the pressure regulating device also includes an adapter disk and a plurality of second ropes, one side of the adapter disk is connected to one end of the first rope, and the other side is connected to the outer ring through the plurality of second ropes, and the plurality of second ropes are distributed along the circumference of the outer ring.

[0018] According to at least one embodiment of the present invention, the plurality of second ropes are evenly distributed along the circumference of the outer ring;

[0019] The outer ring has a first connection portion connected to the second rope, the adapter plate has a second connection portion connected to the second rope, and each of the first connection portions is opposite to a corresponding second connection portion.

[0020] According to at least one embodiment of the present invention, the pressure regulating device further comprises at least one second counterweight, wherein the second counterweight is configured to apply pressure on the top of the elastic support.

[0021] According to at least one embodiment of the present invention, the multi-degree-of-freedom motion platform has six degrees of freedom.

[0022] According to at least one embodiment of the present invention, the displacement measuring device includes at least two laser displacement sensors, and the at least two laser displacement sensors are orthogonally arranged along the circumference of the dynamic friction plate.

[0023] One or more technical solutions provided in the exemplary embodiments of the present invention can achieve at least one of the following beneficial effects.

[0024] In a testing device for a spring-supported dry friction damper according to an exemplary embodiment of the present invention, a static friction plate is mounted on a multi-degree-of-freedom motion platform to simulate the damper's motion trajectory in a two-dimensional plane. A dynamic friction plate is mounted on one end face of the inner ring of the elastic support and abuts against the static friction plate. Two sets of orthogonally arranged restraints abut the outer side of the outer ring of the elastic support, ensuring that the elastic support has only one axial translational degree of freedom. Therefore, the testing device can accurately simulate the relative motion trajectory between the dynamic and static friction plates of the spring-supported dry friction damper. The pairwise opposing restraints accurately measure the forces acting on the spring support during service, such as the elastic force, friction force, or the combined force of the two. A displacement measurement device can be used to measure the displacement of the dynamic friction plate (inner ring), thereby determining the dynamic characteristics of the spring-supported dry friction damper during service, namely, the input (displacement)-output (combined force) variation. Based on this, the testing device according to an exemplary embodiment of the present invention can perform component-level testing on spring-supported dry friction dampers. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings illustrate exemplary embodiments of the present invention and, together with the description, serve to explain the principles of the present invention. These drawings are included to provide a further understanding of the present invention and are incorporated in and constitute a part of this specification.

[0026] Figure 1 This is a schematic diagram of the rotor system model with a spring-supported dry friction damper;

[0027] Figure 2 2 is a schematic diagram of the axonometric structure of a test device for a spring-supported dry friction damper according to an embodiment of the present invention;

[0028] Figure 3 is an axonometric structural diagram of two sets of restraint devices and a bracket according to an embodiment of the present invention;

[0029] Figure 4 is an axonometric structural diagram of a restraint device according to an embodiment of the present invention;

[0030] Figure 5 yes Figure 4 A partial enlarged view of part A;

[0031] Figure 6 is a schematic diagram of a laser optical path of a displacement measuring device according to an embodiment of the present invention;

[0032] Figure 7 is a schematic isometric structural diagram of an elastic support according to an embodiment of the present invention;

[0033] Figure 8 is a schematic diagram of the axonometric structure of the elastic support and the dynamic friction plate according to an embodiment of the present invention;

[0034] Figure 9 is an axonometric structural diagram of a multi-degree-of-freedom motion platform and a static friction plate according to an embodiment of the present invention;

[0035] Figure 10 2 is a schematic isometric structural diagram of a pressure regulating device according to an embodiment of the present invention.

[0036] Reference numerals: 10, restraint device; 11, universal ball; 12, force sensor; 13, base; 131, end plate; 132, slide rail; 133, slider; 14, force plate; 15, linear motion mechanism;

[0037] 20. Multi-degree-of-freedom motion platform;

[0038] 30. Pressure regulating device; 31. First counterweight; 32. First rope; 33. Pulley; 34. Adapter plate; 35. Second rope; 36. Bracket;

[0039] 40. Displacement measuring device; 41. Laser displacement sensor;

[0040] 50. Damper; 51. Dynamic friction plate; 52. Elastic support; 521. Outer ring; 522. Inner ring; 523. Elastic element; 53. Loaded part; 54. Test part; 55. Static friction plate;

[0041] 60. Support structure. DETAILED DESCRIPTION

[0042] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0043] Figure 1This is a schematic diagram of the rotor system model with a spring-supported friction damper. Figure 1 As shown, a spring-loaded dry friction damper consists of an elastic support and a dry friction damper. The aircraft engine rotor is mounted on the shaft, and the elastic support is attached to the shaft's bearings. It moves linearly with the shaft, but does not rotate about its own central axis. The dry friction damper consists of a dynamic friction plate, which is fixed to the elastic support, and a static friction plate, which is fixed to the rotor casing. When the rotor vibrates, the dynamic friction plate, which is fixed to the elastic support, moves linearly with the shaft, causing relative motion with the static friction plate, which is fixed to the rotor casing. The actuator pushes the static friction plate, which in turn presses against the dynamic friction plate, generating friction. This frictional energy dissipation reduces rotor vibration.

[0044] In the related art, research on the dynamic characteristics of elastically supported friction dampers typically involves assembling the damper on a rotor and conducting complete rotor dynamic characteristic tests. Because the dynamic characteristics of an elastically supported friction damper are nonlinear and depend on the clamping force, vibration level, and relative motion trajectory, conducting complete rotor tests cannot accurately reveal the damping mechanism of the damper, and thus cannot provide a theoretical basis for the design of an elastically supported friction damper suitable for aircraft engine rotors.

[0045] To address these issues, the elastic support dry friction damper test apparatus of an exemplary embodiment of the present invention utilizes two sets of restraints to restrict the elastic support to a single axial degree of freedom. These restraints also accurately capture the forces acting on the elastic support while in service. To accurately measure the forces acting on the elastic support, a displacement excitation is applied to the static friction plate, ensuring that the restraints on the elastic support measure both elastic and friction forces. Furthermore, a displacement measurement device allows for real-time measurement of the displacement of the dynamic friction plate, thereby providing insights into the dynamic characteristics of the elastic support while in service.

[0046] Figure 2 2 is a schematic diagram of the axonometric structure of a test device for a spring-supported dry friction damper according to an embodiment of the present invention; Figure 8 is a schematic diagram of the axonometric structure of the elastic support and the dynamic friction plate according to an embodiment of the present invention; Figure 9 Schematic diagram of the axonometric structure of the multi-degree-of-freedom motion platform and the static friction plate according to an embodiment of the present invention. Figure 2 、 Figure 8 and Figure 9As shown, an exemplary embodiment of the present invention provides a test device for an elastically supported dry friction damper. The damper 50 includes an elastic support 52, a static friction plate 55, and a dynamic friction plate 51. The elastic support 52 includes an inner ring 522, an outer ring 521, and an elastic element 523 located in an annular space between the inner ring 522 and the outer ring 521. The dynamic friction plate 51 is provided on one end face of the inner ring 522. The test device includes a multi-degree-of-freedom motion platform 20, a displacement measuring device 40, and two sets of constraint devices 10 arranged orthogonally around the outer ring 521. Each set of constraint devices 10 includes two constraint devices 10, and the two constraint devices 10 in the same set abut against opposite sides of the outer ring 521 respectively. The elastic support 52 retains one axial degree of freedom through the two sets of constraint devices 10. The two sets of constraint devices 10 are used to obtain the force applied to the elastic support 52. The static friction plate 55 is provided on the multi-degree-of-freedom motion platform 20, and the dynamic friction plate 51 abuts against the static friction plate 55. The displacement measuring device 40 is used to obtain the displacement of the dynamic friction plate 51.

[0047] Figure 7 Schematic diagram of the axonometric structure of the elastic support according to the embodiment of the present invention. Figure 7 and Figure 8 As shown, the elastic support 52 consists of an inner ring 522, elastic elements 523, and an outer ring 521. There are multiple elastic elements 523, evenly distributed within the annular space between the outer circumference of the inner ring 522 and the inner circumference of the outer ring 521. One end of the elastic element 523 is connected to the outer circumference of the inner ring 522, and the other end is connected to the inner circumference of the outer ring 521. For example, the elastic element 523 is an S-shaped elastic sheet, with two adjacent S-shaped elastic sheets having opposite bends. The cavity of the inner ring 522 is used to accommodate the rotor shaft. The dynamic friction plate 51 is an annular structure fixed to one end face of the inner ring 522 to form a friction pair with the annular static friction plate 55.

[0048] In the actual operation of the rotor system, the inner ring 522 of the elastic support 52 moves linearly along the rotor axis without rotating around its own central axis. The stiffness of the elastic element 523 changes during the movement (called dynamic stiffness in vibration dynamics), and the outer ring 521 is fixed.

[0049] In practice, the static friction plate 55 is fixed to the multi-degree-of-freedom motion platform 20, and the dynamic friction plate 51 is fixed to one end surface of the inner ring 522 of the elastic support 52. The elastic support 52 is placed on top of the static friction plate 55, ensuring full contact between the dynamic friction plate 51 and the static friction plate 55. The two sets of constraint devices 10 are adjusted so that the four constraint devices 10 are evenly distributed along the circumference of the elastic support 52. That is, adjacent constraint devices 10 are arranged orthogonally to each other, and each constraint device 10 extends radially along the elastic support 52.

[0050] The two constraint devices 10 in the same set of constraint devices 10 are respectively arranged on opposite sides of the elastic support 52. The two sets of constraint devices 10 work together to make the elastic support 52 have only axial translational freedom, that is, the elastic support 52 can only translate in the vertical direction.

[0051] Furthermore, the two sets of restraint devices 10 can also be used to measure the force on the elastic support 52. For example, each set of restraint devices 10 can accurately obtain the force condition of the elastic support 52 in service state in real time by measuring the resultant force in that direction.

[0052] When the multi-degree-of-freedom motion platform 20 is controlled by a computer to perform two-dimensional motion, the static friction plate 55 can be driven to perform two-dimensional motion accordingly. The relative motion trajectory of the dynamic friction plate 51 of the elastic support 52 and the static friction plate 55 can truly reproduce the service status of the elastic support friction damper 50 without having to install it on the rotor as a whole for testing.

[0053] During the test, the displacement measuring device 40 can obtain real-time displacement of the dynamic friction plate 51 in a plane parallel to the end face of the inner ring 522. Based on this, by using two sets of constraint devices 10 to obtain the combined force of friction and elastic force acting on the elastic support 52, as well as the displacement of the dynamic friction plate 51, the input (displacement)-output (combined force) variation characteristics can be obtained, that is, the dynamic characteristics of the elastic support friction damper 50 in service.

[0054] Figure 3 is an axonometric structural diagram of two sets of restraint devices and a bracket according to an embodiment of the present invention; Figure 4 is an axonometric structural diagram of a restraint device according to an embodiment of the present invention; Figure 5 yes Figure 4 A partial enlarged view of part A. Figure 3-Figure 5 As shown, the constraint device 10 includes a base 13 and a universal ball 11 connected to the base 13, and the universal ball 11 abuts against the outer ring 521; in the same group of constraint devices 10, one constraint device 10 includes at least one universal ball 11, and the other constraint device 10 includes at least two universal balls 11.

[0055] For example, in the same set of restraint devices 10, that is, in two opposing restraint devices 10, one restraint device 10 has one universal ball 11, and the other restraint device 10 has two universal balls. The center line connecting the three universal balls 11 in the same set of restraint devices 10 forms an isosceles triangle, and the plane of the isosceles triangle is perpendicular to the axial direction of the elastic support 52.

[0056] Due to the rolling characteristics of the universal ball 11, the universal ball 11 forms point contact with the outer ring 521. The constraint device 10 only provides radial force to the outer ring 521 but not axial force, and will not affect the pressure between the dynamic friction plate 51 and the static friction plate 55. Moreover, the friction forces measured in the two orthogonal directions can be decoupled from each other.

[0057] Furthermore, the line connecting the centers of the three universal balls 11 forms an isosceles triangle, which prevents the constraint device 10 from imparting any shear force or bending moment in the radial plane to the elastic support 52, thereby restricting the elastic support 52's rotational freedom in the radial plane. The coordinated operation of the two sets of constraint devices 10, with orthogonal force transmission paths, allows the elastic support 52 to retain only axial translational freedom.

[0058] It should be noted that the radial plane refers to a plane perpendicular to the central axis of the elastic support 52 .

[0059] like Figure 4 and Figure 5 As shown, each set of restraint devices 10 includes two force sensors 12 , one force sensor 12 is arranged between the base 13 of one restraint device 10 and at least one universal ball 11 , and the other force sensor 12 is arranged between the base 13 of another restraint device 10 and at least two universal balls 11 .

[0060] In the same group of constraint devices 10, one constraint device 10 has a universal ball 11, which is set on a mounting seat, and the mounting seat is connected to the force sensor 12 through a screw, and the force sensor 12 is set on the base 13 through another screw; the other constraint device 10 has two universal balls 11, which are set on a mounting seat, and the mounting seat is connected to the force sensor 12 through a screw, and the force sensor 12 is set on the base 13 through another screw.

[0061] The values ​​measured by the two force sensors 12 of the same set of restraint devices 10 can be used to obtain the resultant elastic force and friction force acting on the outer ring 521 of the elastic support 52 in one radial direction. The values ​​measured by the four force sensors 12 of the two sets of restraint devices 10 can be used to obtain the elastic force and friction force acting on the outer ring 521 in two orthogonal radial directions.

[0062] In some embodiments, in the test device provided by the exemplary embodiment of the present invention, the restraint device 10 also includes a linear motion mechanism 15 provided on the base 13, the universal ball 11 and the force sensor 12 are both connected to the movable end of the linear motion mechanism, and the universal ball 11 can apply a preload force on the outer ring 521 through the linear motion mechanism 15.

[0063] For example, the linear motion mechanism 15 may be a hydraulic cylinder, an electric cylinder, or a pneumatic cylinder. The following description will take the hydraulic cylinder as an example.

[0064] The base 13 includes two slide rails 132, an end plate 131 detachably connected to the two slide rails 132, a slider 133 and a force-bearing plate 14. The slider 133 is slidably arranged between the two slide rails 132, and slide grooves that cooperate with the two slide rails 132 are respectively provided on both sides of the slider 133. The support structure 60 is fixed to the ground or the base. The support structure 60 includes a vertically arranged mounting rod. The slider 133 is provided with a through hole for the mounting rod to pass through, and is fixed to the mounting rod by a fastening screw provided on the side of the slider 133. The two slide rails 132 can move along the slide groove of the slider 133 to adjust the relative position of the universal ball 11 and the outer ring 521 to form point contact.

[0065] The two slide rails 132 and the end plate 131 form a rectangular frame structure. The end plate 131 is generally U-shaped, comprising an end plate body and connecting plates connected to both sides of the end plate body. The two connecting plates are respectively attached to the outer side walls of the two slide rails 132, and each connecting plate has an elongated slot extending in the same direction as the slide rail 132. Fastening screws can be used to secure the connecting plate to the outer side of the slide rail 132 through the slot. The slot also allows the relative position between the end plate 131 and the slide rail 132 to be adjusted and fixed.

[0066] It should be noted that the universal ball transfer 11 and force sensor 12 are mounted on the side of the end plate 131 facing away from the slide rails 132; the load plate 14 is secured to the other side via two studs. The load plate 14 is secured to the movable end of the hydraulic cylinder, thus indirectly connecting the universal ball transfer 11 and force sensor 12 to the movable end of the hydraulic cylinder. For example, a mounting base for the hydraulic cylinder is located between the two slide rails 132 and near the end plate 131, with the fixed end of the hydraulic cylinder mounted on this base.

[0067] In actual application, adjust the position of the slider 133 on the mounting rod and fix the height position of the slider 133 by tightening the screws; then move the slider 133 in the sliding groove through the slide rail 132 and fix it with the tightening screws to make the universal ball 11 abut against the outer ring 521 to form a point contact; loosen the screws in the slot of the connecting plate of the end plate 131; extend the movable end of the hydraulic cylinder, and connect the force plate 14, the end plate 131 and the force sensor 12 and the universal ball 11 connected to the end plate 131 at the movable end, and apply a radial preload force to the elastic support 52 along the radial direction of the elastic support 52, so that the point contact between the universal ball 11 and the outer ring 521 is completely tightened, and finally tighten the screws in the slot of the connecting plate of the end plate 131 to fix the end plate 131 to the slide rail 132.

[0068] The above-mentioned preloading process of the same group of restraint devices 10 is the same and performed simultaneously, and finally the radial preloading of the four restraint devices 10 is completed, so that the elastic support 52 retains only one axial translational degree of freedom.

[0069] For example, Figure 2 and Figure 3 As shown, the support structure 60 fixes the vertical mounting rod on the base through two supporting legs. The base is provided with multiple mounting slots. Each supporting leg is provided with multiple long strip slots. The fastening bolts provided in the mounting slots can pass through the slots on the supporting legs and the supporting legs can be fixed to the base with nuts. The slots of the above-mentioned supporting legs are conducive to fine-tuning the position of the mounting rod.

[0070] Because the dynamic characteristics of a spring-loaded dry friction damper are nonlinear and dependent on the pressure between the dynamic friction plate 51 and the static friction plate 55, testing the dynamic characteristics of the damper 50 under various pressures is necessary to reveal its vibration reduction mechanism under complex motion conditions. Furthermore, since the elastic support 52 is located above the static friction plate 55 and has a significant deadweight, it effectively applies a certain amount of pressure to the static friction plate 55. Therefore, it is impossible to obtain a precise pressure value, resulting in data loss during the dynamic characteristics testing of the damper 50.

[0071] In response to the above problems, Figure 2 and Figure 10 As shown, the test device provided by the exemplary embodiment of the present invention further includes a pressure regulating device 30, which is used to regulate the pressure between the dynamic friction plate 51 and the static friction plate 55, wherein: Figure 10 2 is a schematic isometric structural diagram of a pressure regulating device according to an embodiment of the present invention.

[0072] The pressure regulating device 30 includes a bracket 36, a pulley 33, a first rope 32 and a first counterweight 31. The pulley 33 is rotatably mounted on the bracket 36. One end of the first rope 32 is connected to the elastic support 52, and the other end passes around the pulley 33 and is connected to the first counterweight 31.

[0073] For example, the bracket 36 consists of a horizontal bar, a vertical bar, and a support leg that secures the vertical bar to the base. The support leg has an elongated slot through which bolts pass to secure the vertical bar to the base, allowing for fine adjustment. The vertical bar is located below and in the middle of the horizontal bar. Pulleys 33 are located at each end of the top of the horizontal bar. One end of the first rope 32 is connected to the elastic support 52 and is located directly above it. The other end passes through two pulleys 33 and connects to the first counterweight 31. By varying the weight of the first counterweight 31, the effect of the weight of the elastic support 52 and the dynamic friction plate 51 on the pressure can be reduced. When the required pressure exceeds the weight of the elastic support 52 and the dynamic friction plate 51, a second counterweight included in the pressure regulating device 30 can be added to the top of the outer ring 521 of the elastic support 52. By adding second counterweights of varying weights, the pressure applied to the static friction plate 55 can be varied. Based on this, the adjustment of any pressure size can be achieved, thereby effectively revealing the vibration reduction mechanism of the elastic-supported dry friction damper.

[0074] Exemplarily, the first counterweight 31 and the second counterweight may be weights.

[0075] In order to minimize the influence of the first counterweight 31 on the elastic support 52 in the radial plane to generate shear force or bending moment, as shown in FIG. Figure 10 As shown, the pressure regulating device 30 provided by the exemplary embodiment of the present invention also includes an adapter disk 34 and a plurality of second ropes 35. One side of the adapter disk 34 is connected to one end of the first rope 32, and the other side is connected to the outer ring 521 through the plurality of second ropes 35. The plurality of second ropes 35 are distributed along the circumference of the outer ring 521.

[0076] Exemplarily, multiple second ropes 35 are evenly distributed along the circumference of the outer ring 521; the outer ring 521 has a first connection portion connected to the second ropes 35, and the adapter plate 34 has a second connection portion connected to the second ropes 35, and each first connection portion is opposite to the corresponding second connection portion.

[0077] The adapter plate 34 can be a circular disc. When the other end of the first rope 32 is connected to the first counterweight 31, each second rope 35 is in a vertical position, that is, the entire adapter plate 34 is parallel to the end surface of the outer ring 521. In other words, the first counterweight 31 only provides axial force to the elastic support 52, thereby adjusting the pressure of the elastic support 52 and the dynamic friction plate 51 on the static friction plate 55 to zero. By replacing the first counterweight 31 with a lighter one, the pressure on the static friction plate 55 can be gradually increased until the first counterweight 31 is zero and the pressure on the static friction plate 55 is equal to the weight of the elastic support 52 and the dynamic friction plate 51.

[0078] like Figure 9As shown, in order to realize the trajectory of arbitrary two-dimensional motion of the elastic support friction damper to simulate its actual displacement load in service state, the multi-degree-of-freedom motion platform 20 is a six-degree-of-freedom motion platform.

[0079] Exemplarily, the six-degree-of-freedom motion platform includes a platform, and five telescopic cylinders are hinged at the bottom of the platform. The fixed end of each telescopic cylinder is hinged on the annular base. The extension and retraction of the five telescopic cylinders are controlled by a computer, thereby realizing any motion trajectory of the platform in a two-dimensional plane, that is, the simulation of any motion trajectory of the static friction plate 55 in a two-dimensional plane can be realized.

[0080] like Figure 7 and Figure 8 As shown, four load-bearing parts 53 are further provided on the circumferential side of the outer ring 521. The universal balls 11 of the two sets of constraint devices 10 respectively make point contact with the corresponding load-bearing parts 53. For example, the load-bearing parts 53 have a flat surface, and the universal balls 11 abut against the corresponding load-bearing parts 53. Optionally, the load-bearing parts 53 have a cross-shaped groove to facilitate positioning of one or two universal balls 11 of the constraint device 10. When the constraint device 10 has one universal ball 11, the universal ball 11 can make point contact with the load-bearing part 53 at the center of the cross-shaped groove; when the constraint device 10 has two universal balls 11, the two universal balls 11 can be arranged along the horizontal groove of the cross-shaped groove, respectively making point contact with the load-bearing parts 53.

[0081] Figure 6 FIG. 1 is a schematic diagram of the laser optical path of a displacement measuring device according to an embodiment of the present invention. Figure 6 As shown, the displacement measuring device 40 includes at least two laser displacement sensors 41 , and along the circumference of the dynamic friction plate 51 , the at least two laser displacement sensors 41 are orthogonally arranged.

[0082] In practice, the two laser displacement sensors 41 can measure tiny displacement changes of the dynamic friction plate 51 in two orthogonal radial directions. The dynamic friction plate 51 is fixedly mounted on one end face of the inner ring 522 via an adapter plate. The two laser displacement sensors 41 require a laser illumination plane for measurement, which is limited in its measurement range. To account for potential space constraints, two flat test pieces 54 are installed on the outer circumference of the adapter plate of the dynamic friction plate 51. The planes of the test pieces 54 are perpendicular to the radial planes and away from the outer circumference of the dynamic friction plate 51, shortening the measurement path of the laser displacement sensors 41 within the limited space.

[0083] Exemplarily, the tested parts 54 are orthogonally distributed along the circumference of the dynamic friction plate 51 so as to be opposite to the corresponding laser displacement sensors 41 .

[0084] For example, Figure 2As shown, the laser displacement sensor 41 is a non-contact displacement measuring instrument. The laser displacement sensor 41 can be stably placed on the ground by placing the mounting frame so that the laser of each laser displacement sensor 41 is irradiated onto the plane of the corresponding test piece 54.

[0085] During the test, the six-degree-of-freedom motion platform drives the static friction plate 55 to move along any arbitrary trajectory within a two-dimensional plane. The static friction plate 55, in turn, drives the inner ring 522 of the elastic support 52 through friction. The outer ring 521 of the elastic support 52 remains stationary due to the four restraint devices 10. In the radial plane, the paired force sensors 12 within the same set of restraint devices 10 measure the combined elastic and friction forces acting on the outer ring 521 of the elastic support 52 in real time and accurately. A laser displacement sensor measures minute displacement changes of the dynamic friction plate 51 in two orthogonal radial directions. The pressure between the dynamic and static friction plates 51 and 55 can be adjusted using a pressure regulating device 30. This allows testing of a spring-loaded friction damper under varying pressure and arbitrary two-dimensional relative motion trajectories, reproducing the dynamic characteristics of the spring-loaded friction damper in service and revealing the vibration reduction mechanism of the spring-loaded friction damper in an aircraft engine rotor.

[0086] It should be understood by those skilled in the art that the above embodiments are merely for the purpose of illustrating the present invention clearly, and are not intended to limit the scope of the present invention. For those skilled in the art, other changes or modifications may be made based on the above disclosure, and such changes or modifications are still within the scope of the present invention.

Claims

1. A test device for a spring-loaded friction damper, characterized in that: The damper includes an elastic support, a static friction plate and a dynamic friction plate, wherein the elastic support includes an inner ring, an outer ring and an elastic element located in an annular space between the inner ring and the outer ring, and the dynamic friction plate is provided on one end surface of the inner ring; The test device includes a multi-degree-of-freedom motion platform, a displacement measuring device, and two sets of constraint devices arranged orthogonally around the periphery of the outer ring, each set of constraint devices including two constraint devices, two of the constraint devices in the same set abutting opposite sides of the outer ring respectively; the elastic support retains one axial degree of freedom through the two sets of constraint devices; the two sets of constraint devices are also used to obtain the force applied to the elastic support; The static friction plate is arranged on the multi-degree-of-freedom motion platform, and the dynamic friction plate abuts against the static friction plate; The displacement measuring device is used to obtain the displacement of the dynamic friction plate.

2. The test device according to claim 1, characterized in that The restraint device includes a base and a universal ball connected to the base, wherein the universal ball abuts against the outer ring; In the same group of the constraint devices, one of the constraint devices includes at least one universal ball, and the other constraint device includes at least two universal balls.

3. The test device according to claim 2, characterized in that Each group of the constraint devices includes two force sensors, one of which is arranged between the base of one constraint device and the at least one universal ball, and the other of which is arranged between the base of the other constraint device and the at least two universal balls.

4. The test device according to claim 3, characterized in that In the same group of the constraint devices, one constraint device includes one universal ball, and the other constraint device includes two universal balls.

5. The test device according to claim 3, characterized in that The restraint device further includes a linear motion mechanism provided on the base, the universal ball and the force sensor are both connected to the movable end of the linear motion mechanism, and the universal ball applies a pre-tightening force on the outer ring through the linear motion mechanism.

6. The test device according to claim 3, characterized in that The test device further comprises a pressure regulating device, which is used to regulate the pressure between the dynamic friction plate and the static friction plate.

7. The test device according to claim 6, characterized in that The pressure regulating device includes at least one second counterweight for applying pressure on the top of the elastic support.

8. The test device according to claim 7, characterized in that The multi-degree-of-freedom motion platform has six degrees of freedom.

9. The test device according to claim 8, characterized in that The displacement measuring device includes at least two laser displacement sensors.

10. The test device according to claim 9, characterized in that At least two laser displacement sensors are arranged orthogonally along the circumference of the dynamic friction plate.

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