A method for testing the dynamic characteristics of a spring-supported dry friction damper

Abstract

The application provides a kind of elastic support dry friction damper dynamics characteristic test method, it is related to the field of dynamics test technology.Test method includes: providing a test device, test device includes multiple degree of freedom motion platform and multiple constraint devices;Static friction piece is placed on multiple degree of freedom motion platform, and elastic support with dynamic friction piece is placed between multiple constraint devices, and dynamic friction piece is attached to the top of static friction piece;Based on the motion trajectory data of damper in engine rotor system, control multiple degree of freedom motion platform moves in two-dimensional plane;The displacement of dynamic friction piece and the resultant force of elastic support in radial plane are obtained, the dynamics characteristic of damper in service state is obtained, and the radial plane refers to the plane perpendicular to the central axis of the elastic support.The test method can accurately reveal the dynamics characteristic of elastic support dry friction damper.

Description

Technical Field

[0001] This invention relates to the field of dynamic testing technology, and in particular to a method for testing the dynamic characteristics of a spring-loaded dry friction damper. Background Technology

[0002] Elastic dry friction dampers play a crucial role in vibration reduction of rotor systems. They possess advantages such as simple structure and ease of active control, and have broad application prospects in vibration reduction and suppression of aero-engine rotor systems. An elastic dry friction damper consists of an elastic support and a dry friction damper. The elastic support is mounted on the bearing of the rotor shaft and moves with the shaft without rotating around its own central axis. The dry friction damper consists of a moving friction plate and a stationary friction plate. The moving friction plate is fixed to the elastic support, and the stationary friction plate is fixed to the rotor casing.

[0003] In related technologies, the dynamic characteristics of spring-loaded dry friction dampers are usually tested using whole-machine testing methods, which makes it difficult to reveal the dynamic characteristics of spring-loaded dry friction dampers. Summary of the Invention

[0004] The purpose of this invention is to provide a method for testing the dynamic characteristics of a spring-loaded dry friction damper, so as to solve the technical problem of difficulty in revealing the dynamic characteristics of the spring-loaded dry friction damper.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for testing the dynamic characteristics of a spring-loaded dry friction damper, wherein the damper is used in an engine rotor system, and the testing method includes:

[0007] A test apparatus is provided, the test apparatus comprising a multi-degree-of-freedom motion platform and multiple constraint devices;

[0008] The static friction plate is placed on the multi-degree-of-freedom motion platform, and the elastic support with the dynamic friction plate is placed between the multiple constraint devices, with the dynamic friction plate attached to the top of the static friction plate.

[0009] Based on the motion trajectory data of the damper in the engine rotor system, the multi-degree-of-freedom motion platform is controlled to move in a two-dimensional plane.

[0010] By obtaining the displacement of the dynamic friction plate and the resultant force of the elastic support in the radial plane, the dynamic characteristics of the damper under service conditions can be obtained. The radial plane refers to the plane perpendicular to the central axis of the elastic support.

[0011] According to at least one embodiment of the present invention, an elastic support with a dynamic friction plate is placed between the plurality of constraint devices, comprising:

[0012] The elastic support is restricted to having only one axial degree of freedom.

[0013] According to at least one embodiment of the present invention, the number of the restraint devices is four, the restraint devices include at least one omnidirectional ball, and the test method includes:

[0014] The four constraint devices are evenly arranged along the circumference of the elastic support, and at least one universal ball of each constraint device abuts against the outer ring of the elastic support to form a point contact.

[0015] According to at least one embodiment of the present invention, four load-bearing components are further provided on the periphery of the outer ring, and the test method includes:

[0016] Each of the constraint devices' omnidirectional balls makes point contact with the corresponding load-bearing component.

[0017] According to at least one embodiment of the present invention, the constraint device further includes a base and a linear motion mechanism disposed on the base, wherein the universal ball and the force sensor are both connected to the movable end of the linear motion mechanism, and the testing method includes:

[0018] The movable ends of the linear motion mechanisms in the two opposing constraint devices are simultaneously extended so that the point contact between the omnidirectional ball and the outer ring is fully pressed to achieve preloading.

[0019] According to at least one embodiment of the present invention, one of the two opposing constraint devices includes a gimbal ball, and the other includes two gimbal balls; the test method includes:

[0020] Adjust the two opposing constraint devices so that the line connecting the centers of the three omnidirectional balls forms an isosceles triangle, and the plane containing the isosceles triangle is perpendicular to the axial direction of the elastic support.

[0021] According to at least one embodiment of the present invention, obtaining the displacement of the dynamic friction plate and the resultant force of the elastic support in the radial plane includes:

[0022] Based on the data from the force sensors in the two opposing constraint devices, the resultant force of the elastic force and frictional force acting on the elastic support in two orthogonal directions is obtained.

[0023] According to at least one embodiment of the present invention, obtaining the displacement of the dynamic friction plate and the resultant force of the elastic support in the radial plane further includes:

[0024] Two laser displacement sensors are orthogonally mounted on the periphery of the elastic support, wherein each laser displacement sensor is opposite to the dynamic friction plate.

[0025] According to at least one embodiment of the present invention, the dynamic friction pad is disposed on the inner ring of the elastic support via an adapter plate, and the test method further includes:

[0026] Two test pieces with flat surfaces are provided on the outer periphery of the adapter plate, so that the test pieces are away from the outer circumferential surface of the dynamic friction plate, wherein the flat surface of each test piece is opposite to the corresponding laser displacement sensor.

[0027] According to at least one embodiment of the present invention, before obtaining the displacement of the dynamic friction plate and the resultant force of the elastic support in the radial plane to obtain the dynamic characteristics of the damper under service conditions, the test method further includes:

[0028] A preset pressure is applied to the top of the elastic support.

[0029] According to at least one embodiment of the present invention, 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 an annular space between the inner ring and the outer ring. The dynamic friction plate is disposed on one end face of the inner ring.

[0030] The test apparatus 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, with the two constraint devices in the same set abutting 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 on the elastic support.

[0031] The static friction plate is disposed on the multi-degree-of-freedom motion platform, and the dynamic friction plate abuts against the static friction plate;

[0032] The displacement measuring device is used to obtain the displacement of the dynamic friction plate.

[0033] According to at least one embodiment of the present invention, the restraint device includes a base and a universal ball connected to the base, the universal ball abutting against the outer ring;

[0034] In the same group of said restraint devices, one of said restraint devices includes at least one of said omnidirectional balls, and another of said restraint devices includes at least two said omnidirectional balls.

[0035] According to at least one embodiment of the present invention, each set of the constraint devices includes two force sensors, one force sensor being disposed between the base of one constraint device and the at least one omnidirectional ball, and the other force sensor being disposed between the base of another constraint device and the at least two omnidirectional balls.

[0036] According to at least one embodiment of the present invention, in the same group of constraint devices, one constraint device includes one omnidirectional ball, another constraint device includes two omnidirectional balls, the center line of the three omnidirectional balls forms an isosceles triangle, and the plane containing the isosceles triangle is perpendicular to the axial direction of the elastic support.

[0037] According to at least one embodiment of the present invention, the constraint device further includes a linear motion mechanism disposed on the base, wherein 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 to the outer ring through the linear motion mechanism.

[0038] According to at least one embodiment of the present invention, the test apparatus further includes a pressure regulating device for regulating the pressure between the dynamic friction plate and the static friction plate.

[0039] 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 mounted on the bracket, and one end of the first rope is connected to the elastic support, while the other end passes around the pulley and is connected to the first counterweight.

[0040] According to at least one embodiment of the present invention, the pressure regulating device further includes an adapter plate and a plurality of second ropes, one side of the adapter plate being connected to one end of the first rope, and the other side being connected to the outer ring via the plurality of second ropes, the plurality of second ropes being distributed circumferentially along the outer ring.

[0041] According to at least one embodiment of the present invention, the plurality of second ropes are uniformly distributed along the circumference of the outer ring;

[0042] The outer ring has a first connecting portion connected to the second rope, and the adapter plate has a second connecting portion connected to the second rope, with each first connecting portion opposite to a corresponding second connecting portion.

[0043] According to at least one embodiment of the present invention, the pressure regulating device further includes at least one second counterweight for applying pressure to the top of the elastic support.

[0044] According to at least one embodiment of the present invention, the multi-degree-of-freedom motion platform has six degrees of freedom.

[0045] According to at least one embodiment of the present invention, the displacement measuring device includes at least two laser displacement sensors, which are orthogonally arranged along the circumference of the dynamic friction plate.

[0046] In one or more technical solutions provided in the exemplary embodiments of the present invention, at least one of the following beneficial effects can be achieved.

[0047] The exemplary embodiment of this invention discloses a method for testing the dynamic characteristics of a spring-supported dry friction damper. A static friction plate is placed on a multi-degree-of-freedom motion platform. Based on the damper's motion trajectory data in the engine rotor system, the multi-degree-of-freedom motion platform is controlled by analog signals to move in a two-dimensional plane, thus realistically simulating the damper's motion trajectory in the two-dimensional plane. A dynamic friction plate, mounted on an elastic support, abuts against the static friction plate. A constraint device abuts against the outer side of the elastic support's outer ring, ensuring the elastic support has only one axial translational degree of freedom. Therefore, the test setup can simulate the relative motion trajectory between the dynamic and static friction plates of the spring-supported dry friction damper. Through the pairwise constraint devices, the force conditions of the elastic support under service conditions can be accurately obtained, such as elastic force, frictional force, or the resultant force of both. The displacement of the dynamic friction plate can be obtained through a displacement measuring device, thereby acquiring the dynamic characteristics of the spring-supported dry friction damper. Based on this, by placing the static friction plate on the multi-degree-of-freedom motion platform—that is, applying displacement excitation to the static friction plate instead of the dynamic friction plate—the magnitude of the force on the elastic support can be accurately measured. The test method of the exemplary embodiment of the present invention can achieve accurate testing under service conditions by reproducing the arbitrary and complex two-dimensional motion trajectory of the ballistic dry friction damper, thereby revealing the dynamic characteristics of the ballistic dry friction damper. Attached Figure Description

[0048] The accompanying drawings illustrate exemplary embodiments of the invention and, together with the description thereof, serve to explain the principles of the invention. These drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification.

[0049] Figure 1 This is a flowchart illustrating the dynamic characteristics testing method for a spring-loaded dry friction damper according to an embodiment of the present invention.

[0050] Figure 2 This is an isometric structural schematic diagram of the test apparatus for a spring-supported dry friction damper according to an embodiment of the present invention;

[0051] Figure 3 This is an isometric structural schematic diagram of two sets of constraint devices and supports according to an embodiment of the present invention;

[0052] Figure 4 This is an isometric structural schematic diagram of a constraint device according to an embodiment of the present invention;

[0053] Figure 5 yes Figure 4 A magnified view of part A;

[0054] Figure 6 This is a schematic diagram of the laser optical path of a displacement measuring device according to an embodiment of the present invention;

[0055] Figure 7 This is an isometric structural diagram of an elastic support according to an embodiment of the present invention;

[0056] Figure 8 This is an isometric structural diagram of the elastic support and dynamic friction plate according to an embodiment of the present invention;

[0057] Figure 9 This is an isometric structural diagram of a multi-degree-of-freedom motion platform and a static friction plate according to an embodiment of the present invention;

[0058] Figure 10 This is an isometric structural schematic diagram of a pressure regulating device according to an embodiment of the present invention;

[0059] Figure 11 This is a flowchart illustrating a method for testing the dynamic characteristics of a spring-loaded dry friction damper according to another embodiment of the present invention. Detailed Implementation

[0060] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0061] In related technologies, the method of testing the dynamic characteristics of spring-supported dry friction dampers by testing the damper and rotor together as a whole cannot accurately reveal the dynamic characteristics of the spring-supported dry friction damper.

[0062] Figure 1 This is a schematic flowchart of a method for testing the dynamic characteristics of a spring-loaded dry friction damper according to an embodiment of the present invention. Figure 1 As shown, the method for testing the dynamic characteristics of a spring-loaded dry friction damper provided by an exemplary embodiment of the present invention includes the following steps:

[0063] Step 101: Provide a test apparatus, which includes a multi-degree-of-freedom motion platform 20 and multiple constraint devices 10.

[0064] The six-degree-of-freedom motion platform is placed stably on the workbench, and the computer control system raises the six-degree-of-freedom motion platform to the height required for testing. At the same time, four constraint devices 10 are placed stably around the six-degree-of-freedom motion platform in appropriate positions. Two opposing constraint devices 10 form a group, and the lines connecting the two groups of constraint devices 10 are orthogonal to each other and adjusted to the corresponding height.

[0065] Step 102: Place the static friction plate 55 on the multi-degree-of-freedom motion platform 20, place the elastic support 52 with the dynamic friction plate 51 between the multiple constraint devices 10, and place the dynamic friction plate 51 against the top of the static friction plate 55.

[0066] Figure 2 This is an isometric structural schematic diagram of the test apparatus for a spring-supported dry friction damper according to an embodiment of the present invention; Figure 8 This is an isometric structural diagram of the elastic support and dynamic friction plate according to an embodiment of the present invention; Figure 9 This is an isometric structural diagram of a multi-degree-of-freedom motion platform and a static friction plate according to an embodiment of the present invention. Figure 2 , Figure 8 and Figure 9 As shown, the exemplary embodiment of the present invention provides a test apparatus for a spring-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 the annular space between the inner ring 522 and the outer ring 521. The dynamic friction plate 51 is disposed on one end face of the inner ring 522. The test apparatus 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 periphery of the outer ring 521. Each set of constraint devices 10 includes two constraint devices 10, with the two constraint devices 10 in the same set abutting against opposite sides of the outer ring 521. 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 on the elastic support 52. The static friction plate 55 is disposed 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.

[0067] Figure 7 This is an isometric structural diagram of an elastic support according to an embodiment of the present invention. Figure 7 and Figure 8As shown, the elastic support 52 consists of an inner ring 522, elastic elements 523, and an outer ring 521. Multiple elastic elements 523 are evenly distributed within the annular space between the outer circumferential surface of the inner ring 522 and the inner circumferential surface of the outer ring 521. One end of each elastic element 523 is connected to the outer circumferential surface of the inner ring 522, and the other end is connected to the inner circumferential surface of the outer ring 521. For example, the elastic element 523 may be an S-shaped elastic sheet, with adjacent S-shaped elastic sheets having opposite bending directions. The cavity of the inner ring 522 houses the rotor shaft. The moving friction plate 51 is an annular structure fixed to one end face of the inner ring 522 to cooperate with the annular static friction plate 55 to form a friction pair.

[0068] In the actual operation of the rotor system, the inner ring 522 of the elastic support 52 moves along the rotor shaft without rotating around its own central axis. The stiffness of the elastic element 523 changes during the movement (called dynamic stiffness in vibration dynamics), while the outer ring 521 remains fixed.

[0069] In practical applications, the static friction plate 55 is fixedly mounted on the multi-degree-of-freedom motion platform 20, and the dynamic friction plate 51 is fixedly mounted on one end face of the inner ring 522 of the elastic support 52. The elastic support 52 is placed on top of the static friction plate 55 so that the dynamic friction plate 51 and the static friction plate 55 are in full contact.

[0070] For example, four restraint devices 10 are evenly arranged along the circumference of the elastic support 52, and at least one universal ball 11 of each restraint device 10 abuts against the outer ring 521 of the elastic support 52 to form point contact. For example, the two sets of restraint devices 10 are adjusted so that the four restraint devices 10 are evenly distributed along the circumference of the elastic support 52, that is, two adjacent restraint devices 10 are orthogonally arranged to each other, and each restraint device 10 extends radially along the elastic support 52.

[0071] For example, when four load-bearing members 53 are provided on the periphery of the outer ring 521, the universal ball 11 of each constraint device 10 makes point contact with the corresponding load-bearing member 53.

[0072] It should be noted that the inner ring 522 of the aforementioned elastic support 52 is circular, while the inner circumferential surface of the outer ring 521 is circular. The outer circumferential surface can be set according to the actual situation and does not necessarily have to be circular. For example, on the sides where the four load-bearing members 53 are located, the corresponding portion of the outer circumferential surface of the outer ring 521 is a plane. Therefore, the axial and radial directions of the aforementioned elastic support 52 can be the axial and radial directions of the inner ring 522.

[0073] By using the four constraint devices 10 arranged in pairs and orthogonally in two groups, the circumferential degree of freedom of the elastic support 52 is restricted, limiting the elastic support 52 to having only one axial degree of freedom. Specifically, two constraint devices 10 in the same group are respectively arranged on opposite sides of the elastic support 52. The two groups of constraint devices 10 work together so that the elastic support 52 has only an axial translational degree of freedom, that is, the elastic support 52 can only translate in the vertical direction, so that in the test method of the following embodiment, the pressure of the elastic support 52 on the static friction plate can be changed by a corresponding adjustment method.

[0074] Step 103: Based on the motion trajectory data of the damper 50 in the engine rotor system, control the multi-degree-of-freedom motion platform 20 to move in a two-dimensional plane.

[0075] For example, the motion trajectory data of the spring-loaded dry friction damper 50 in the engine rotor system is first acquired. Based on this motion trajectory data, it is converted into analog control signals by a data processing unit and input into a computer. The computer then outputs these analog control signals to a driver. The driver is communicatively connected to the hydraulic devices in each multi-degree-of-freedom motion platform 20, controlling the multi-degree-of-freedom motion platform 20 to reproduce the target motion trajectory. When the multi-degree-of-freedom motion platform 20 performs two-dimensional motion, it can drive the static friction plate 55 to perform two-dimensional motion accordingly. Therefore, the relative motion trajectory between the dynamic friction plate 51 and the static friction plate 55 of the elastic support 52 can realistically reproduce the service state of the spring-loaded dry friction damper 50 without requiring it to be installed on the rotor for overall testing.

[0076] Step 104: Obtain the displacement of the dynamic friction plate 51 and the resultant force of the elastic support 52 in the radial plane to obtain the dynamic characteristics of the damper 50 in service. The radial plane refers to the plane perpendicular to the central axis of the elastic support 52.

[0077] For example, the two sets of constraint devices 10 can also be used to measure the force on the elastic support 52. For example, each set of constraint devices 10 can obtain the force on the elastic support 52 in service condition in real time by measuring the resultant force in that direction.

[0078] In some embodiments, the resultant force of the elastic force and frictional force acting on the elastic support 52 in two orthogonal directions can be obtained based on the data from the force sensors 12 in the two opposing constraint devices 10.

[0079] Furthermore, during the test, the displacement measuring device 40 can acquire the displacement of the dynamic friction plate 51 in the plane parallel to the end face of the inner ring 522 in real time. Based on this, by acquiring the resultant force of the frictional force and elastic force on the elastic support 52 and the displacement of the dynamic friction plate 51 in real time through the two sets of constraint devices 10, the input (displacement)-output (resultant force) variation characteristics can be obtained, that is, the dynamic characteristics of the elastic dry friction damper 50 under service conditions can be obtained.

[0080] Figure 3 This is an isometric structural schematic diagram of two sets of constraint devices and supports according to an embodiment of the present invention; Figure 4 This is an isometric structural schematic diagram of a constraint device according to an embodiment of the present invention; Figure 5 yes Figure 4 A magnified view of part A. (See image below.) Figures 3-5 As shown, the restraint device 10 includes a base 13 and a universal ball 11 connected to the base 13. The universal ball 11 abuts against the outer ring 521. In the same group of restraint devices 10, one restraint device 10 includes at least one universal ball 11, and another restraint device 10 includes at least two universal balls 11.

[0081] For example, in the same set of constraint devices 10, that is, in two opposing constraint devices 10, one constraint device 10 has one universal ball 11, and the other constraint device 10 has two universal balls. The line connecting the centers of the three universal balls 11 in the same set of constraint devices 10 forms an isosceles triangle, and the plane containing the isosceles triangle is perpendicular to the axial direction of the elastic support 52.

[0082] Due to the rolling characteristics of the universal ball 11, the universal ball 11 forms point contact with the outer peripheral surface of the outer ring 521. The constraint device 10 only provides radial force to the outer ring 521 and does not provide axial force. It 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.

[0083] In some embodiments, the two opposing constraint devices 10 are adjusted so that the line connecting the centers of the three universal balls 11 forms an isosceles triangle, and the plane containing the isosceles triangle is perpendicular to the axial direction of the elastic support 52. This isosceles triangle formation prevents the constraint devices 10 from providing any shear force or bending moment in the radial plane to the elastic support 52, thus restricting the rotational freedom of the elastic support 52 in the radial plane. Through the coordinated operation of the two sets of constraint devices 10 with orthogonal force transmission paths, the elastic support 52 retains only the axial translational degree of freedom.

[0084] It should be noted that the radial plane refers to the plane perpendicular to the central axis of the elastic support 52.

[0085] like Figure 4 and Figure 5 As shown, each set of restraint devices 10 includes two force sensors 12. One force sensor 12 is disposed between the base 13 of one restraint device 10 and at least one universal ball 11, and the other force sensor 12 is disposed between the base 13 of another restraint device 10 and at least two universal balls 11.

[0086] In the same set of constraint devices 10, one constraint device 10 has a universal ball 11, which is mounted on a mounting base. The mounting base is connected to a force sensor 12 via a screw, and the force sensor 12 is mounted on a base 13 via another screw. The other constraint device 10 has two universal balls 11, which are mounted on a mounting base. The mounting base is connected to a force sensor 12 via a screw, and the force sensor 12 is mounted on a base 13 via another screw.

[0087] The resultant force of the elastic force and friction force on the outer ring 521 of the elastic support 52 in one radial direction can be obtained by measuring the values ​​obtained by the two force sensors 12 of the same set of constraint devices 10. The elastic force and friction force on the outer ring 521 in two orthogonal radial directions can be obtained by measuring the values ​​obtained by the four force sensors 12 of the two sets of constraint devices 10.

[0088] In some embodiments, the test method provided by the exemplary embodiments of the present invention further includes a linear motion mechanism 15 disposed 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. The universal ball 11 can apply a preload force on the outer ring 521 through the linear motion mechanism 15.

[0089] For example, the linear motion mechanism 15 can be one of a hydraulic cylinder, an electric cylinder, or a pneumatic cylinder. The following description uses a hydraulic cylinder as an example.

[0090] 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 disposed between the two slide rails 132, and each side of the slider 133 has a groove that mates with the two slide rails 132. The support structure 60 is fixed to the ground or a base platform. The support structure 60 includes a vertically arranged mounting rod. The slider 133 has a through hole for the mounting rod to pass through, and is fixed to the mounting rod by fastening screws disposed around the slider 133. The two slide rails 132 can move along the grooves of the slider 133 to adjust the relative position of the universal ball 11 and the outer ring 521 to form point contact.

[0091] Two slide rails 132 and an end plate 131 form a rectangular frame structure. The end plate 131 is roughly U-shaped and includes a main body and connecting plates on both sides of the main 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. The extension direction of the slot is the same as the extension direction of the slide rail 132. Fastening screws can be used to fix the connecting plate to the outside of the slide rail 132 through the slot, and the relative position between the end plate 131 and the slide rail 132 can be adjusted and fixed through the slot.

[0092] It should be noted that the universal ball 11 and the force sensor 12 are disposed on the side of the end plate 131 facing away from the slide rail 132; the force plate 14 is fixed to the other side by two studs. The force plate 14 is fixed to the movable end of the hydraulic cylinder, therefore, the universal ball 11 and the force sensor 12 are indirectly connected to the movable end of the hydraulic cylinder. For example, a mounting seat for the hydraulic cylinder is provided between the two slide rails 132, near the end plate 131, and the fixed end of the hydraulic cylinder is disposed on this mounting seat.

[0093] In practical applications, the position of slider 133 on the mounting rod is adjusted and the height of slider 133 is fixed by fastening screws; then, slide rail 132 moves in the groove of slider 133 and is fixed by fastening screws to form point contact between the universal ball 11 and the outer ring 521; loosen the screws in the slot of the connecting plate of end plate 131; extend the movable end of the hydraulic cylinder, and apply 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 fully pressed, and finally tighten the screws in the slot of the connecting plate of end plate 131 to fix end plate 131 to slide rail 132.

[0094] The preloading process of the same set of constraint devices 10 is the same and carried out simultaneously, and finally the radial preloading of the four constraint devices 10 is completed, so that the elastic support 52 retains only one axial translational degree of freedom.

[0095] For example, such as Figure 2 and Figure 3 As shown, the support structure 60 fixes the vertical mounting rod to the base platform through two legs. The base platform is covered with multiple mounting slots, and each leg is provided with multiple elongated slot holes. Fastening bolts provided in the mounting slots can pass through the slot holes on the legs and the legs can be fixed to the base platform with nuts. The slot holes of the legs are conducive to fine-tuning the position of the mounting rod.

[0096] Figure 11 This is a schematic flowchart of a method for testing the dynamic characteristics of a spring-loaded dry friction damper according to another embodiment of the present invention. Figure 11 As shown, the method for testing the dynamic characteristics of a spring-loaded dry friction damper according to an exemplary embodiment of the present invention includes the following steps:

[0097] Step 1101: Place the static friction plate on the multi-degree-of-freedom motion platform, and place the elastic support with the dynamic friction plate between multiple constraint devices.

[0098] Specifically, the universal ball 11 is fixedly connected to the universal ball base by its own M5 bolts, and then the universal ball base is fixedly connected to the force sensor 12 by its own M5 threaded hole and its own M5 bolts.

[0099] The end plate 131 is fixedly connected to the force sensor 12 by M5 bolts, and the force plate 14 is fixedly connected to the end plate 131 by two M5 bolts.

[0100] Connect slider 133 to mounting rod with four M8 bolts; initially connect slider 133 to slide rail 132 with four M8 bolts so that slide rail 132 can still move along slide groove of slider 133.

[0101] The hydraulic cylinder is connected to the slide rail 132 by bolts; the end plate 131 is connected to the slide rail 132 by M8 bolts, but not completely fixed, so as to facilitate the subsequent preloading of the elastic support by the hydraulic cylinder.

[0102] Adjust the height of the six-degree-of-freedom motion platform so that the groove of the loaded component 53 is flush with the center of the omnidirectional ball 11.

[0103] By moving the slide rail 132 along the slide groove of the slider 133, the distance between the universal ball 11 and the load-bearing component 53 is adjusted so that the universal ball 11 and the side of the load-bearing component 53 form point contact; tighten the four bolts used to connect the slider 133 and the slide rail 132.

[0104] At this point, one restraint device is installed. Repeat this step to complete the installation of the other three restraint devices 10. When installing the other three restraint devices 10, the lines connecting the three contact points formed by two opposing restraint devices 10 and the load-bearing member 53 form an isosceles triangle.

[0105] The screws in the slots of the connecting plate of the end plate 131 are used to extend the movable end of the hydraulic cylinder. The force plate 14, the end plate 131, the force sensor 12 and the universal ball 11 connected to the movable end are used to 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 fully pressed. Finally, the screws in the slots of the connecting plate of the end plate 131 are tightened to fix the end plate 131 to the slide rail 132, thus completing the preload.

[0106] The preloading process of the same group of constraint devices 10 is the same and carried out simultaneously, and finally the radial preloading of the four constraint devices 10 is completed.

[0107] Step 1102: Apply a preset pressure to the top of the elastic support or reduce the weight of the elastic support and the dynamic friction plate.

[0108] Since the dynamic characteristics of the spring-supported dry friction damper are nonlinear and related to the pressure between the dynamic friction plate 51 and the static friction plate 55, it is necessary to conduct experiments on the dynamic characteristics of the damper 50 under different pressure conditions in order to reveal the vibration reduction mechanism of the spring-supported dry friction damper under complex motion conditions.

[0109] Meanwhile, since the elastic support 52 is located above the static friction plate 55, and the weight of the elastic support 52 is relatively large, it is equivalent to applying a certain pressure to the static friction plate 55. Therefore, it is impossible to obtain any pressure value between the two, resulting in missing data for the dynamic characteristic test of the damper 50.

[0110] In response to the above problems, such as Figure 2 and Figure 10 As shown, in the test method provided by the exemplary embodiment of the present invention, the test apparatus 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. Figure 10 This is an isometric structural diagram of a pressure regulating device according to an embodiment of the present invention.

[0111] 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.

[0112] For example, the bracket 36 consists of a horizontal bar, a vertical bar, and legs for fixing the vertical bar to the base. The legs have elongated slots through which bolts pass to fix the vertical bar to the base, allowing for fine-tuning. The vertical bar is located below the horizontal bar and in the middle of the horizontal bar. Pulleys 33 are installed at both ends 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 the elastic support 52; the other end passes around the two pulleys 33 and connects to the first counterweight 31. By changing the weight of the first counterweight 31, the influence of the self-weight of the elastic support 52 and the dynamic friction plate 51 on the pressure can be reduced. When the required pressure is greater than the self-weight of the elastic support 52 and the dynamic friction plate 51, a second counterweight, including the pressure adjusting device 30, can be added to the top of the outer ring 521 of the elastic support 52. By adding second counterweights of different weights, the pressure applied to the static friction plate 55 can be changed. Based on this, the pressure between the elastic support 52 and the dynamic friction plate 51 can be adjusted arbitrarily, thereby effectively revealing the vibration reduction mechanism of the elastic support dry friction damper.

[0113] For example, the first counterweight 31 and the second counterweight mentioned above can be weights.

[0114] To minimize the impact of the first counterweight 31 on the elastic support 52 in the radial plane, such as Figure 10 As shown, the pressure regulating device 30 provided in the exemplary embodiment of the present invention further includes an adapter plate 34 and a plurality of second ropes 35. One side of the adapter plate 34 is connected to one end of the first rope 32, and the other side is connected to the outer ring 521 through a plurality of second ropes 35. The plurality of second ropes 35 are distributed along the circumference of the outer ring 521.

[0115] For example, a plurality of second ropes 35 are evenly distributed along the circumference of an outer ring 521; the outer ring 521 has a first connecting portion connected to the second ropes 35, and the adapter plate 34 has a second connecting portion connected to the second ropes 35, with each first connecting portion opposite to a corresponding second connecting portion.

[0116] 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, all the second ropes 35 are in a vertical state, that is, the entire adapter plate 34 is parallel to the end face of the outer ring 521. In other words, the first counterweight 31 only provides the axial force of 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. Then, by replacing the first counterweight 31 with a lighter one, the pressure on the static friction plate 55 is gradually increased until the first counterweight 31 is zero, and the pressure on the static friction plate 55 is the weight of the elastic support 52 and the dynamic friction plate 51.

[0117] Step 1103: Based on the motion trajectory data of the damper in the engine rotor system, control the multi-degree-of-freedom motion platform to move in a two-dimensional plane.

[0118] like Figure 9 As shown, in order to realize the trajectory of arbitrary two-dimensional motion of the spring-loaded dry friction damper, and to simulate its actual displacement load under service conditions, the aforementioned multi-degree-of-freedom motion platform 20 is a six-degree-of-freedom motion platform.

[0119] For example, the six-degree-of-freedom motion platform includes a platform with five telescopic cylinders hinged to the bottom of the platform. The fixed end of each telescopic cylinder is hinged to an 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, simulating any motion trajectory of the static friction plate 55 in a two-dimensional plane.

[0120] like Figure 7 and Figure 8 As shown, four load-bearing components 53 are also provided around the outer ring 521. The universal balls 11 of the two sets of restraint devices 10 respectively make point contact with the corresponding load-bearing components 53. For example, the load-bearing component 53 has a plane, and the universal ball 11 abuts against the corresponding load-bearing component 53. Optionally, the load-bearing component 53 has a cross-shaped groove to facilitate the positioning of one or two universal balls 11 of the restraint device 10. When the restraint device 10 has one universal ball 11, the universal ball 11 can make point contact with the load-bearing component 53 at the center of the cross-shaped groove; when the restraint device 10 has two universal balls 11, the two universal balls 11 can be arranged along the horizontal groove of the cross-shaped groove and make point contact with the load-bearing component 53 respectively.

[0121] Step 1104: Obtain the displacement of the dynamic friction plate and the resultant force of the elastic support in the radial plane to obtain the dynamic characteristics of the damper under service conditions.

[0122] Figure 6 This 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, which are orthogonally arranged along the circumference of the dynamic friction plate 51.

[0123] In practical applications, two laser displacement sensors 41 can measure minute displacement changes of the moving friction plate 51 in two orthogonal radial directions. The moving 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 irradiation plane for measurement. However, the laser displacement sensors 41 have limitations in their measurement range. Considering the potential space constraints, two test pieces 54 with planes are provided on the outer periphery of the adapter plate of the moving friction plate 51. The planes of the test pieces 54 are perpendicular to the radial plane and away from the outer circumferential surface of the moving friction plate 51, so as to shorten the measurement path of the laser displacement sensors 41 within a limited space.

[0124] For example, the two test pieces 54 are orthogonally distributed along the circumference of the dynamic friction plate 51, that is, the phase difference between the two test pieces 54 in the circumference of the dynamic friction plate 51 is 90°, so that the test pieces 54 are opposite to the corresponding laser displacement sensor 41.

[0125] For example, such as Figure 2 As shown, the laser displacement sensor 41 is a non-contact displacement measuring instrument. The laser displacement sensor 41 can be installed by placing the mounting bracket stably on the ground, so that the laser of each laser displacement sensor 41 can irradiate the plane of the corresponding measured part 54.

[0126] During the test, the six-degree-of-freedom motion platform drives the static friction plate 55 to move along any trajectory in a two-dimensional plane. The static friction plate 55, in turn, drives the inner ring 522 of the elastic support 52 to move through friction. The outer ring 521 of the elastic support 52 remains stationary under the action of the four constraint devices 10. In the radial plane, the values ​​measured by the paired force sensors 12 in the same set of constraint devices 10 can accurately obtain the resultant force of the elastic force and friction force on the outer ring 521 of the elastic support 52 in real time. The laser displacement sensor can obtain the minute displacement changes of the dynamic friction plate 51 in two orthogonal radial directions. The pressure between the dynamic friction plate 51 and the static friction plate 55 can be adjusted by the pressure adjustment device 30. Based on this, by changing the size of the first or second counterweight and the output settings of the six-degree-of-freedom motion platform, the test of the spring-supported dry friction damper under a combination of variable pressure and arbitrary two-dimensional relative motion trajectory can be realized, reproducing the dynamic characteristics of the spring-supported dry friction damper in service. The test method of the exemplary embodiment of the present invention can accurately reveal the vibration reduction mechanism of the spring-supported dry friction damper.

[0127] Those skilled in the art should understand that the above embodiments are merely for illustrating the present invention and are not intended to limit the scope of the invention. Those skilled in the art can make other changes or modifications based on the above disclosure, and these changes or modifications still fall within the scope of the present invention.

Claims

1. A method for testing the dynamic characteristics of a pinned-end dry-friction damper, characterized by, The damper is used in an engine rotor system, and the damper comprises an elastic support, a static friction sheet and a dynamic friction sheet, 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, and the dynamic friction sheet is arranged on one end face of the inner ring; the test method comprises: Providing a test device, the test device comprising a multi-degree-of-freedom motion platform and a plurality of constraint devices; Fixing the static friction sheet on the multi-degree-of-freedom motion platform, placing the elastic support with the dynamic friction sheet between the plurality of constraint devices, limiting the elastic support to have only one axial degree of freedom, and making the dynamic friction sheet adhere to the top of the static friction sheet; Controlling the multi-degree-of-freedom motion platform to move in a two-dimensional plane based on the motion trajectory data of the damper in the engine rotor system; Obtaining the displacement of the dynamic friction sheet and the resultant force of the elastic support in a radial plane to obtain the dynamic characteristics of the damper in the service state, the radial plane being a plane perpendicular to the central axis of the elastic support.

2. The test method of claim 1, wherein, The number of the constraint devices is four, the constraint devices comprising at least one universal ball, and the test method comprising: Arranging the four constraint devices uniformly along the circumference of the elastic support, and abutting the at least one universal ball of each constraint device against the outer ring of the elastic support to form a point contact.

3. The test method of claim 2, wherein, The circumference of the outer ring is further provided with four load receivers, and the test method comprising: Respectively making the universal balls of each constraint device point-contact with the corresponding load receivers.

4. The test method of claim 2, wherein, The constraint device further comprises a base and a linear motion mechanism arranged on the base, and the universal ball and the force sensor are connected to the movable end of the linear motion mechanism, and the test method comprising: Simultaneously elongating the movable ends of the linear motion mechanisms of the two oppositely arranged constraint devices to completely compress the point contact between the universal ball and the outer ring to realize preloading.

5. The test method of claim 4, wherein, One of the two oppositely arranged constraint devices comprises one universal ball, and the other comprises two universal balls, and the test method comprising: Adjusting the two oppositely arranged constraint devices to make the center line of the three universal balls form an isosceles triangle, and the plane of the isosceles triangle being perpendicular to the axial direction of the elastic support.

6. The test method of claim 4, wherein, Obtaining the displacement of the dynamic friction sheet and the resultant force of the elastic support in a radial plane, comprising: According to the data of the force sensors of the two oppositely arranged constraint devices, obtaining the resultant force of the elastic force and the friction force received by the elastic support in two orthogonal directions.

7. The test method of claim 6, wherein, Obtaining the displacement of the dynamic friction sheet and the resultant force of the elastic support in a radial plane, further comprising: Orthogonally installing two laser displacement sensors on the periphery of the elastic support, wherein each laser displacement sensor is opposite to the dynamic friction sheet.

8. The test method of claim 7, wherein, The dynamic friction sheet is arranged on the inner ring of the elastic support through an adapter disc, and the test method further comprising: Two test pieces with flat surfaces are arranged on the outer circumferential side of the adapter plate, so that the test pieces are away from the outer circumferential surface of the dynamic friction plate, wherein the flat surface of each test piece is opposite to the corresponding laser displacement sensor.

9. The test method of claim 6, wherein, Before obtaining the displacement of the dynamic friction plate and the resultant force of the elastic support in the radial plane, the test method further comprises: A preset pressure is applied to the top of the elastic support.

Images