A quick test device for the service life of an armature assembly of an electro-hydraulic servo valve

Abstract

The application provides a kind of electro-hydraulic servo valve armature assembly life quick test device, comprising: fixture, counterweight, strain gauge, strain meter, laser vibration meter, fast fourier transform processor, vibration table controller, vibration table, data collector and computer;Solve the problem that the test cycle of traditional fatigue loading test is long and difficult to apply to armature assembly life test, the load of armature assembly in the test process is basically consistent with the actual use condition, the life test under different loads can be carried out by adjusting the stroke closed loop parameters, the test process can be unattended, realize the rapid iteration design of electro-hydraulic servo valve product.

Description

Technical Field

[0001] This invention belongs to the field of electro-hydraulic servo valve technology, specifically relating to a rapid testing device for the lifespan of the armature assembly of an electro-hydraulic servo valve. Background Technology

[0002] Electro-hydraulic servo valves are electro-hydraulic conversion elements that transform electrical signals into hydraulic output signals, and are the core components of electro-hydraulic servo control systems. Electro-hydraulic servo valves have advantages such as high control precision, fast dynamic response, and long service life, and are widely used in control systems in aerospace, metallurgy, chemical, and shipbuilding industries. With the rapid development of related technologies, high demands are being placed on the reliability of electro-hydraulic servo valves.

[0003] As the core component of the servo valve, the armature assembly consists of a thin-walled Bourdon tube and a slender reaction rod. The Bourdon tube and reaction rod are subjected to alternating loads during operation and are prone to fatigue failure, which is a key factor restricting the improvement of the reliability of electro-hydraulic servo valves.

[0004] Traditional fatigue loading tests have long testing cycles and are difficult to apply to small components such as armature assemblies, which cannot meet the needs of rapid product iteration design. There is an urgent need for a rapid testing device and method for the life of electro-hydraulic servo valve armature assemblies. Summary of the Invention

[0005] This invention proposes a rapid testing device for the lifespan of the armature assembly in an electro-hydraulic servo valve. This device can replace traditional fatigue loading tests, enabling the rapid and accurate determination of the armature assembly's lifespan during the product design phase and facilitating rapid iteration of product design.

[0006] This invention provides a rapid testing device for the life of an armature assembly of an electro-hydraulic servo valve, comprising: a fixture, a counterweight, a strain gauge, a strain meter, a laser vibrometer, a fast Fourier transform processor, a vibration table controller, a vibration table, a data acquisition unit, and a computer;

[0007] The fixture is fixed on the vibration table and is used to hold the armature assembly under test. The armature assembly under test is equipped with a counterweight and a strain gauge.

[0008] The strain gauge is connected to the strain meter via wires, and the strain meter is connected to the data acquisition unit via data cables.

[0009] The laser vibration meter is used to monitor the end vibration displacement of the armature assembly under test. It is connected to the fast Fourier transform processor via a data cable. The fast Fourier transform processor is connected to the vibration table controller via a data cable.

[0010] The vibration table controller is connected to the vibration table and the computer via a data cable; the data acquisition unit is connected to the computer via a data cable.

[0011] The computer is used to send the initial vibration power, preset vibration frequency, and target stroke to the vibration table controller;

[0012] The vibration table controller is used to control the vibration of the vibration table according to the initial vibration power and preset vibration frequency, drive the end of the armature assembly under test to vibrate, and adjust the output power of the vibration table according to the actual stroke and target stroke of the end of the armature assembly under test provided by the fast Fourier transform processor, until the actual stroke matches the target stroke.

[0013] The computer is used to record the vibration time and send a termination command to the vibration table controller when the strain amplitude monitored by the strain gauge decays to a preset multiple of the steady-state amplitude, thereby stopping the test and determining the life of the armature assembly under test based on the preset vibration frequency and vibration time.

[0014] Optionally, the initial vibration power P = πFxf;

[0015] Where f is the natural frequency of the armature assembly and counterweight under test; the natural frequency is obtained by establishing a finite element model and performing modal analysis; the natural frequency is less than the threshold frequency, which is the maximum frequency that the shaking table can withstand;

[0016] F is the excitation force amplitude, x is the vibration amplitude, and F and x are the excitation force amplitude and vibration amplitude at the natural frequency; F and x are obtained by establishing a finite element model and performing harmonic response simulation.

[0017] Optionally, when the natural frequency of the armature assembly under test is less than the threshold frequency, the mass of the counterweight is 0.

[0018] When the natural frequency of the armature assembly under test is greater than the threshold frequency, select the lightest counterweight weight that satisfies the condition that the natural frequencies of the armature assembly under test and the counterweight are less than the threshold frequency.

[0019] Optionally, the preset vibration frequency is the frequency corresponding to the maximum vibration amplitude point in the vibration amplitude-excitation frequency curve; the vibration amplitude-excitation frequency curve is obtained by performing a vibration frequency sweep on the armature assembly under test within the frequency range of 0 to the threshold.

[0020] Optionally, the armature assembly being tested is a spring tube 8 or a reaction rod 15.

[0021] Optionally, the fixture includes: a fixed base 1, bottom mounting screw holes 2, reinforcing ribs 3, spring tube mounting slots 4, reaction rod fixing slots 5, three reaction rod fixing studs 6, and three reaction rod fixing nuts 7;

[0022] The fixed base 1 is an inverted T-shape, with bottom mounting screw holes 2 on the bottom surface. It is fixedly connected to the vibration table by screws passing through the bottom mounting screw holes 2.

[0023] A reinforcing rib 3 is also provided between the bottom surface of the fixed base 1 and the upright plate;

[0024] The upright plate of the fixed base 1 is provided with a reaction rod fixing groove 5;

[0025] When the armature assembly being tested is a reaction rod 15, the head of the reaction rod 15 is set in the reaction rod fixing groove 5, and three reaction rod fixing studs 6 are inserted into the reaction rod fixing groove 5 from the top surface and both sides of the vertical plate and are pressed against the reaction rod 15; a reaction rod fixing nut 7 is respectively fitted on the three reaction rod fixing studs 6.

[0026] The bottom of the reaction rod fixing groove 5 is provided with a spring tube mounting groove 4;

[0027] When the armature assembly under test is a spring tube 8, two spring tube mounting bolts 13 pass through the spring tube mounting groove 4 to fix the spring tube 8 in the reaction rod fixing groove 5, and are tightened by the spring tube mounting nut 14.

[0028] Optionally, an armature 9 is welded onto the spring tube 8; a spring tube counterweight 10 is installed on each side of the middle part of the armature 9, and the spring tube counterweight 10 is fixed by spring tube counterweight mounting bolts 11 and counterweight mounting nuts 12.

[0029] The strain gauge is installed at the thin-walled root of the spring tube 8;

[0030] A laser vibration meter was used to measure the displacement at the end of armature 9.

[0031] Optionally, the counterweight 17 of the reaction rod is clamped to the tail of the reaction rod 15 by the counterweight screw 16 of the reaction rod;

[0032] The strain gauge is installed on the cylindrical section of the reaction rod 15;

[0033] The laser vibration meter measures the tail displacement of the reaction rod 15.

[0034] Optional, the preset multiplier is 70%.

[0035] Optionally, the computer includes a display screen;

[0036] The laser vibrometer is also connected to a data acquisition unit;

[0037] The computer is also used to display on the screen the actual travel of the end vibration of the armature assembly under test and the strain amplitude monitored by the strain gauge.

[0038] This invention proposes a rapid testing device for the life of the armature assembly of an electro-hydraulic servo valve, which solves the problems of long test cycles and difficulty in applying traditional fatigue loading tests to armature assembly life testing. The load on the armature assembly during the test is basically consistent with the actual operating conditions. By adjusting the stroke closed-loop parameters, life tests under different loads can be carried out. The test process can be unattended, enabling rapid iterative design of electro-hydraulic servo valve products. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the fixture in the rapid testing device for the lifespan of the electro-hydraulic servo valve armature assembly of the present invention.

[0040] Figure 2 Installation diagram for Bourdon tube life test Figure 1 ;

[0041] Figure 3 Installation diagram for Bourdon tube life test Figure 2 ;

[0042] Figure 4 Installation diagram for reaction bar life test;

[0043] Figure 5 Schematic diagram of rapid life test for Bourdon tubes;

[0044] Figure 6 Schematic diagram of rapid life test principle for reaction bar;

[0045] Explanation of reference numerals in the attached figures:

[0046] 1-Fixed base, 2-Bottom mounting screw hole, 3-Reinforcing rib, 4-Bourdon tube mounting slot, 5-Reaction rod fixing slot, 6-Reaction rod fixing stud, 7-Reaction rod fixing nut, 8-Bourdon tube, 9-Armature, 10-Bourdon tube counterweight, 11-Bourdon tube counterweight mounting bolt, 12-Counterweight mounting nut, 13-Bourdon tube mounting bolt, 14-Bourdon tube mounting nut, 15-Reaction rod, 16-Reaction rod counterweight screw, 17-Reaction rod counterweight. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0049] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited in each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0050] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0051] like Figure 1-6 As shown, this invention provides a rapid testing device for the lifespan of an electro-hydraulic servo valve armature assembly, including a composite special fixture for armature assembly lifespan testing, the structure of which is as follows: Figure 1 As shown, the fixture consists of a fixed base 1, bottom mounting screw holes 2, reinforcing ribs 3, spring tube mounting groove 4, reaction rod fixing groove 5, reaction rod fixing stud 6, and reaction rod fixing nut 7.

[0052] The fixture is connected to the vibration table using screws via the mounting screw holes 2 on the bottom surface of the fixed base 1. The spring tube mounting slot 4 is used to connect the spring tube 8 to the fixture. The reaction rod fixing slot 5 is used for installing the reaction rod 15. The reaction rod fixing stud 6 is used to clamp the reaction rod 15. The reaction rod fixing nut 7 is used to tighten the reaction rod fixing stud 6, preventing it from loosening during vibration. The spring tube and reaction rod are installed using different methods during testing. The spring tube installation method is as follows: Figure 2 As shown, to ensure the load on the Bourdon tube matches the actual working conditions, the armature 9 is welded to the Bourdon tube 8. Two Bourdon tube mounting bolts 13 pass through the Bourdon tube mounting slot 4 to fix the Bourdon tube 8 to the fixture and are tightened with Bourdon tube mounting nuts 14. Two Bourdon tube counterweights 10 are mounted on the head of the armature 9, and the Bourdon tube counterweights 10 are fixed by Bourdon tube counterweight mounting bolts 11 and counterweight mounting nuts 12. The reaction bar installation method is as follows. Figure 3 As shown. The head of the reaction rod 15 is placed on the lower surface of the reaction rod fixing groove 5, and three reaction rod fixing studs 6 are screwed in until the bottom surface of the reaction rod fixing studs 6 presses the head of the reaction rod 15 tightly, and then the three reaction rod fixing nuts 7 are tightened.

[0053] This application provides a rapid testing device for the lifespan of the armature assembly of an electro-hydraulic servo valve, which can achieve rapid and accurate testing of the lifespan of the core components of the armature assembly, the spring tube and the reaction rod.

[0054] The testing system consists of a special fixture, parts (spring tubes or reaction bars), counterweights, a laser vibrometer, a fast Fourier transform processor, a vibration table controller, a vibration table, strain gauges, strain meters, a data acquisition unit, and a computer.

[0055] When used for Bourdon tube life testing, the testing apparatus is as follows: Figure 5 As shown, the spring tube is mounted on a special fixture using the aforementioned method, and the special fixture is mounted on the vibration table using mounting screws.

[0056] Strain gauges are attached to the thin-walled surface of the Bourdon tube and connected to a strain gauge via wires. The strain gauge is connected to a data acquisition unit via a data cable. A laser vibrometer is used to monitor the vibration displacement of the armature at the illustrated location. It is connected to the data acquisition unit and a Fast Fourier Transform (FFT) processor via data cables. The FFT processor is connected to the vibration table controller via a data cable, and the vibration table controller is connected to the vibration table via a data cable. The data acquisition unit is connected to a computer via a data cable. The computer is connected to the vibration table controller via a data cable. The computer is used to visualize and monitor strain and vibration displacement data, and to set the vibration frequency and target stroke for the vibration table controller. The laser vibrometer monitors the displacement at the end of the armature. The displacement data is transmitted to the vibration table controller via the FFT processor. The vibration table controller compares the actual stroke with the target stroke and adjusts the output power of the vibration table until the actual stroke and target stroke are essentially matched. The strain gauge monitors the surface strain of the Bourdon tube. When the strain amplitude decays to 70% of the initial amplitude, the computer records the vibration time and sends a termination command to the vibration table controller to stop the test. At this point, the lifespan of the Bourdon tube is the vibration frequency multiplied by the vibration time.

[0057] When used for reaction bar life testing, the testing device is as follows: Figure 6As shown, the reaction rod is mounted on a special fixture using the aforementioned method, and the fixture is mounted on the vibration table using mounting screws. Strain gauges are attached to the position shown on the reaction rod and connected to a strain gauge via wires. The strain gauge is connected to a data acquisition unit via a data cable. A laser vibrometer is used to monitor the vibration displacement of the small ball at the end of the reaction rod at the position shown. It is connected to the data acquisition unit and the Fast Fourier Transform (FFT) processor via data cables. The FFT processor is connected to the vibration table controller via a data cable, and the vibration table controller is connected to the vibration table via a data cable. The data acquisition unit is connected to a computer via a data cable. The computer is connected to the vibration table controller via a data cable. The computer is used to visualize and monitor strain and vibration displacement data, and to set the vibration frequency and target stroke for the vibration table controller. The laser vibrometer monitors the displacement at the end of the armature. The displacement data is transmitted to the vibration table controller via the FFT processor. The vibration table controller compares the actual stroke with the target stroke and adjusts the vibration table output power until the actual stroke and target stroke are essentially matched. Strain gauges are used to monitor the surface strain of the reaction bar. When the strain amplitude decays to 70% of the initial amplitude, the computer records the vibration time and sends a termination command to the vibration table controller to stop the test. At this time, the life of the reaction bar is the vibration frequency multiplied by the vibration time.

[0058] This application relates to a rapid testing method for the lifespan of an armature assembly in an electro-hydraulic servo valve. The implementation steps are as follows:

[0059] Step 1: Establish finite element models of the spring tube and reaction rod. Obtain the natural frequencies of the parts through modal analysis. If the natural frequencies of the parts are higher than 1000Hz, they can be analyzed according to... Figure 2 , Figure 3 Set a counterweight at the appropriate location. The mass of the counterweight can be adjusted. Perform modal analysis again. After multiple modal analyses, the mass of the counterweight can be determined.

[0060] Step 2: Establish a finite element model including the test platform, fixtures, parts and counterweights, perform harmonic response simulation, and obtain the relationship between the excitation force amplitude and the vibration amplitude. Based on the relationship between the excitation force amplitude and the vibration amplitude at the natural frequency obtained in Step 1, preliminarily determine the excitation power required by the vibration table. The excitation power can be expressed as:

[0061] P=πFxf

[0062] Where P is the excitation power, F is the excitation force amplitude, x is the vibration amplitude, and f is the excitation frequency.

[0063] Step 3: Use a vibration table to perform a vibration frequency sweep on the part, with a frequency range of (0~1000)Hz. Monitor the amplitude of the part during the frequency sweep process using a laser vibration meter. The collected data is transmitted to a computer to plot the vibration amplitude-excitation frequency curve. The frequency corresponding to the point of maximum amplitude is the natural frequency.

[0064] Step 4: Set the target stroke and vibration frequency for the life test to the vibration controller via computer, set the initial excitation power to the excitation power obtained in step 2, turn on the vibration table, and monitor the vibration displacement and strain changes via computer.

[0065] Step 5: When the number of vibration cycles reaches 10,000,000 or the strain amplitude decays to 70% of the initial amplitude, the computer automatically issues a termination command, and the vibration table stops. The number of cycles at this point is the cycle life of the part.

[0066] The above-described embodiments are merely preferred embodiments of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be included within the scope of protection of the present invention.

Claims

1. A rapid testing device for the lifespan of an armature assembly in an electro-hydraulic servo valve, characterized in that, include: Fixtures, counterweights, strain gauges, strain meters, laser vibration meters, fast Fourier transform processors, vibration table controllers, vibration tables, data acquisition units, and computers; The fixture is fixed on the vibration table and is used to hold the armature assembly under test. The armature assembly under test is equipped with a counterweight and a strain gauge. The strain gauge is connected to the strain meter via wires, and the strain meter is connected to the data acquisition unit via data cables. The laser vibration meter is used to monitor the end vibration displacement of the armature assembly under test. It is connected to the fast Fourier transform processor via a data cable. The fast Fourier transform processor is connected to the vibration table controller via a data cable. The vibration table controller is connected to the vibration table and the computer via a data cable; the data acquisition unit is connected to the computer via a data cable. The computer is used to send the initial vibration power, preset vibration frequency, and target stroke to the vibration table controller; The vibration table controller is used to control the vibration of the vibration table according to the initial vibration power and preset vibration frequency, drive the end of the armature assembly under test to vibrate, and adjust the output power of the vibration table according to the actual stroke and target stroke of the end of the armature assembly under test provided by the fast Fourier transform processor, until the actual stroke matches the target stroke. The computer is used to record the vibration time and send a termination command to the vibration table controller when the strain amplitude monitored by the strain gauge decays to a preset multiple of the steady-state amplitude, thereby stopping the test and determining the life of the armature assembly under test based on the preset vibration frequency and vibration time.

2. The rapid testing device for the lifespan of the armature assembly of an electro-hydraulic servo valve according to claim 1, characterized in that, Initial vibration power P = πFxf; Where f is the natural frequency of the armature assembly and counterweight under test; the natural frequency is obtained by establishing a finite element model and performing modal analysis; the natural frequency is less than the threshold frequency, which is the maximum frequency that the shaking table can withstand; F is the excitation force amplitude, x is the vibration amplitude, and F and x are the excitation force amplitude and vibration amplitude at the natural frequency; F and x are obtained by establishing a finite element model and performing harmonic response simulation.

3. The rapid testing device for the lifespan of the armature assembly of an electro-hydraulic servo valve according to claim 1, characterized in that, When the natural frequency of the armature assembly being tested is less than the threshold frequency, the mass of the counterweight is 0. When the natural frequency of the armature assembly under test is greater than the threshold frequency, select the lightest counterweight weight that satisfies the condition that the natural frequencies of the armature assembly under test and the counterweight are less than the threshold frequency.

4. The rapid testing device for the lifespan of the armature assembly of an electro-hydraulic servo valve according to claim 1, characterized in that, The preset vibration frequency is the frequency corresponding to the maximum vibration amplitude point in the vibration amplitude-excitation frequency curve; the vibration amplitude-excitation frequency curve is obtained by performing a vibration frequency sweep on the armature assembly under test within the frequency range of 0 to the threshold.

5. The rapid testing device for the lifespan of the armature assembly of an electro-hydraulic servo valve according to claim 1, characterized in that, The armature assembly under test is a spring tube (8) or a reaction rod (15).

6. The rapid testing device for the lifespan of the armature assembly of an electro-hydraulic servo valve according to claim 5, characterized in that, The fixture includes: a fixed base (1), screw holes on the bottom surface (2), reinforcing ribs (3), spring tube mounting slots (4), reaction rod fixing slots (5), three reaction rod fixing studs (6) and three reaction rod fixing nuts (7); The fixed base (1) is an inverted T-shape, with bottom mounting screw holes (2) on the bottom surface. It is fixedly connected to the vibration table by screws passing through the bottom mounting screw holes (2). A reinforcing rib (3) is also provided between the bottom surface of the fixed base (1) and the upright plate; The upright plate of the fixed base (1) is provided with a reaction rod fixing groove (5); When the armature assembly under test is a reaction rod (15), the head of the reaction rod (15) is set in the reaction rod fixing groove (5), and three reaction rod fixing studs (6) are inserted into the reaction rod fixing groove (5) from the top surface and two sides of the vertical plate and press against the reaction rod (15); reaction rod fixing nuts (7) are respectively fitted on the three reaction rod fixing studs (6); The bottom of the reaction rod fixing groove (5) is provided with a spring tube mounting groove (4); When the armature assembly under test is a spring tube (8), two spring tube mounting bolts (13) pass through the spring tube mounting groove (4) to fix the spring tube (8) in the reaction rod fixing groove (5) and tighten it with the spring tube mounting nut (14).

7. The rapid testing device for the lifespan of the armature assembly of an electro-hydraulic servo valve according to claim 6, characterized in that, An armature (9) is welded onto the spring tube (8); a spring tube counterweight (10) is installed on each side of the middle part of the armature (9), and the spring tube counterweight (10) is fixed by spring tube counterweight mounting bolts (11) and counterweight mounting nuts (12); The strain gauge is installed at the thin-walled root of the spring tube (8); The laser vibration meter measures the displacement of the end of the armature (9).

8. The rapid testing device for the lifespan of the armature assembly of an electro-hydraulic servo valve according to claim 6, characterized in that, The counterweight (17) of the reaction rod is clamped to the tail of the reaction rod (15) by the counterweight screw (16); The strain gauge is installed on the cylindrical section of the reaction rod (15); The laser vibration meter measures the tail displacement of the reaction rod (15).

9. The rapid testing device for the lifespan of the armature assembly of an electro-hydraulic servo valve according to claim 1, characterized in that, The preset multiplier is 70%.

10. The rapid testing device for the lifespan of the armature assembly of an electro-hydraulic servo valve according to claim 1, characterized in that, A computer includes a display screen; The laser vibrometer is also connected to a data acquisition unit; The computer is also used to display on the screen the actual travel of the end vibration of the armature assembly under test and the strain amplitude monitored by the strain gauge.

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