Pneumatic exciter

Abstract

The application discloses a kind of pneumatic exciter, including exciter end cover, high-pressure cylinder, flow guide device, piston assembly and airflow regulating disc, one end of airflow regulating disc drive shaft is fixedly installed in the inside of shell by rotating bearing, and airflow regulating disc is fixedly installed on the airflow regulating disc drive shaft in the inside of shell one end;Airflow regulating disc drive shaft is installed with drive wheel disc at the outside of shell one end;Airflow regulating disc outer wall surface convex one side is provided with high-pressure cylinder;Piston assembly is installed in the piston chamber of shell upper portion;Flow guide device is installed in the airflow regulating disc outside of piston chamber bottom portion;Exciter end cover is installed on the side of shell opposite to drive wheel disc, and the wall surface of exciter end cover is provided with exhaust hole, for the gas in piston chamber exhaust into exhaust passage is discharged.The excitation force of a large amount of value can be output by adjusting the pressure in high-pressure cylinder, and the output excitation force of wide frequency range and higher frequency can be realized by the rapid rotation of orifice plate rotating disc.

Description

Technical Field

[0001] This invention relates to a pneumatic vibrator. Background Technology

[0002] During flight, solid rocket motors are subjected to aerodynamic forces that couple with the engine structure and internal processes, generating combustion oscillations that further induce strong pressure fluctuations, threatening normal engine operation. Therefore, it is necessary to develop an excitation device to simulate these flight aerodynamic loads.

[0003] Exciters used in solid rocket motor testing are mainly of electric and electro-hydraulic types, and consist primarily of a signal generator, a power amplifier, and an excitation device (see appendix). Figure 1 It is used to apply small-amplitude excitation to the engine during modal testing to obtain the dynamic response of different parts of the engine and to obtain multi-mode distributions. The required excitation force is typically 0–500 N, and the excitation frequency can cover 0–2 kHz.

[0004] Electric vibrator, structure shown in the appendix Figure 2 The device consists of a push rod 1, a spring 2, an excitation coil 3 installed in a magnet 4, and a drive coil 5. When the coils 5 and 3 are subjected to an amplified alternating current, according to the principle that a fluid in a magnetic field experiences force, the coils will be subjected to an electrodynamic force proportional to the current I0. This force is transmitted to the object being measured through the push rod, which is the excitation force.

[0005] The structure and working principle of the electro-hydraulic vibrator are shown in the appendix. Figure 3 The signal from the signal generator, after being amplified, is transmitted through an electro-hydraulic servo valve 7, which consists of an electric vibrator, a control valve, and a power valve, to control the oil circuit, causing the piston 8 to reciprocate. The piston is then excited by a push rod 8. Oil at a certain pressure is input to the piston end, forming a static pressure P_static, which applies a preload to the excited object. A force sensor measures the alternating excitation force P_1 and the static pressure P_static.

[0006] An electric vibrator generates an electric excitation force through alternating current in a coil, which drives a push rod to produce a periodically varying output force. An electro-hydraulic vibrator generates electro-hydraulic forces of different magnitudes and frequencies by driving an electro-hydraulic servo valve, thus achieving the excitation force output.

[0007] Electric vibrators can generate high output frequencies, up to 3kHz, but their output force is small and cannot meet the excitation force requirement of 2kN. Electro-hydraulic vibrators have larger output forces, up to 30kN or more, but their output frequency is low, usually only within 100Hz. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a pneumatic exciter to solve the problem of simultaneously achieving high excitation force output and medium-to-high excitation frequency output and adjustment.

[0009] To solve the existing technical problems, the technical solution adopted by the present invention is as follows: a pneumatic vibrator, including a vibrator end cover, a high-pressure cylinder, a flow guiding device, a piston assembly, and an airflow regulating disc. One end of the airflow regulating disc drive shaft is fixed inside the housing via a rotating bearing, and the airflow regulating disc is fixed on the airflow regulating disc drive shaft at one end inside the housing. A drive wheel is installed at the other end of the airflow regulating disc drive shaft located outside the housing. The airflow regulating disc is a circular disc with a raised outer wall surface, and an air inlet hole and an air outlet hole are respectively provided on the outer wall surface of the disc. A high-pressure cylinder is installed on the raised side of the outer wall surface of the airflow regulating disc. The high-pressure cylinder has corresponding air vents on its cylinder wall corresponding to the air inlet holes on the side wall of the airflow regulating disc. An air inlet channel is also provided on the wall surface of the high-pressure cylinder, through which gas enters the high-pressure cylinder, and then through the air inlet channel of the high-pressure cylinder. The vent hole enters the air inlet hole of the airflow regulating disk, and the gas is discharged into the exhaust channel inside the housing through the air outlet hole of the airflow regulating disk. The piston assembly is installed in the piston chamber at the top of the housing. The piston of the piston assembly is slidably sealed to the housing by a dynamic sealing ring. The top of the piston contacts the test piece to transmit the excitation force to the test piece. The flow guiding device is installed on the outside of the airflow regulating disk at the bottom of the piston chamber. The flow guiding device is provided with vent holes corresponding to the air inlet and outlet holes on the outer wall of the airflow regulating disk. When the airflow regulating disk rotates, the air inlet and outlet holes on the airflow regulating disk and the vent holes on the flow guiding device gradually connect. Through continuous air intake and exhaust, sinusoidal pressure waves with different waveforms and periods are generated. The vibrator end cover is installed on the side of the housing opposite to the drive wheel. The wall of the vibrator end cover is provided with an exhaust hole to discharge the gas discharged from the piston chamber into the exhaust channel.

[0010] Furthermore, the air inlet and outlet holes of the airflow regulating disc of the present invention preferably include L-shape, circle or rectangle.

[0011] Furthermore, the piston bottom of the piston assembly described in this invention is preferably arc-shaped.

[0012] This device employs a pneumatic excitation mode, using a rotary table with different channels to regulate the pressure of the gas flowing out of the high-pressure cylinder, generating a pressure wave of a specific frequency. This wave then acts on a standard piston, achieving a sinusoidal output excitation force with adjustable frequency and force. This device can meet the requirements for high-force output as well as medium-to-high excitation frequency output and adjustment, combining the advantages of both electric and electro-hydraulic vibrators.

[0013] This vibrator controls the magnitude and waveform of the excitation force output through the combined action of cylinder pressure, airflow regulating disc, and piston area. The airflow regulating disc, by setting airflow channels of different shapes on the side and cooperating with the airflow channels on the shell partition, realizes the output and adjustment of different pressure waveforms. The orifice plate shape includes L-shaped, rectangular, and circular. The airflow regulating disc is driven to rotate by an asynchronous motor. During the rotation, the frequency of the output force is adjusted by adjusting the speed of the two rows of air holes. The piston assembly has an arc-shaped bearing surface, which can be matched with the shape of the airflow regulating disc and the shell partition, and transmits the excitation force to the test piece through a pin device.

[0014] This invention provides an adjustable output force of 0–20 kN and an adjustable frequency of 0–1000 Hz. Compared with traditional excitation force simulation devices, this device has advantages such as a larger output force and more precise controllable output force. It can provide technical support for the study of combustion stability in solid rocket motors.

[0015] The vibrator of this invention can output a large amount of excitation force by adjusting the pressure inside the high-pressure cylinder, with the excitation force reaching more than 20kN, thus making up for the limited output force of electric vibrators.

[0016] The vibrator of this invention can achieve a wide frequency range and a high frequency output excitation force through the rapid rotation of the perforated plate turntable, covering a range of 0 to 1 kHz, thus making up for the deficiency of the low output frequency of the electro-hydraulic vibrator. Attached Figure Description

[0017] Figure 1 : Existing exciter composition diagram;

[0018] Figure 2 : Schematic diagram of the structure and working principle of an electric vibrator. The symbols in the diagram are: 1-Push rod, 2-Spring, 3-Excitation coil, 4-Magnet, 5-Drive coil;

[0019] Figure 3 : Schematic diagram of the structure and working principle of the electro-hydraulic vibrator. In the diagram, the following are marked: 6-top rod, 7-electro-hydraulic servo valve, 8-piston;

[0020] Figure 4 : Pneumatic vibrator structure diagram, labeled as follows: 9-vibrator end cover, 10-airflow regulating disc drive shaft, 11-rotating bearing, 12-high pressure cylinder, 13-flow guide device, 14-piston assembly, 15-airflow regulating disc, 16-drive wheel, 17-airflow regulating disc base;

[0021] Figure 5 Piston assembly structure diagram, labeled: 18 - Piston chamber;

[0022] Figure 6: Airflow regulating disc structure diagram, labeled: 19 - inner air outlet, 20 - outer air inlet;

[0023] Figure 7 : Pneumatic vibrator system composition diagram, labeled as: 21-stepper motor, 22-clutch, 23-pneumatic vibrator device, 24-air supply system. Detailed Implementation

[0024] The present invention will be further described below with reference to the embodiments. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0025] As attached Figure 4 As shown, a pneumatic vibrator mainly consists of a vibrator end cover 9, an airflow regulating disc drive shaft 10, a rotating bearing 11, a high-pressure cylinder 12, a flow guiding device 13, a piston assembly 14, an airflow regulating disc 15, and a drive wheel 16. Its working principle is as follows: nitrogen or air is pressurized to a set pressure in the high-pressure cylinder 12, and then enters the piston chamber through the air inlet of the airflow regulating disc 15 and the flow guiding device 13. During this process, the airflow regulating disc 15 and the flow guiding device 13 work together to generate a sinusoidal pressure wave, driving the piston assembly 14 to generate a sinusoidal excitation force. The frequency of the sinusoidal excitation force is determined by the rotational speed of the drive wheel 16 and the airflow regulating disc drive shaft 10. The airflow regulating disc 15 is mounted on the airflow regulating disc drive shaft 10 and is limited by the rotating bearing 11.

[0026] The high-pressure cylinder 12 is made of high-strength alloy steel and has an inflation pressure range of 0 to 20 MPa. The wall of the high-pressure cylinder 12 is provided with an air inlet channel and a pressure monitoring channel for inflation and real-time monitoring of cylinder pressure.

[0027] Airflow regulating disc 15, the structure of which is shown in the appendix. Figure 6 The airflow regulating disc 15 is a circular turntable with a ring of air inlet and outlet holes on its side wall. The controlled shapes include L-shapes, circles, and rectangles. The airflow regulating disc 15 works in conjunction with the vents of the flow guide device 13. When the pulley drives the airflow regulating disc 15 to rotate, the different shaped vents on the airflow regulating disc 15 gradually connect with the vents on the flow guide device 13. Through continuous air intake and exhaust, sinusoidal pressure waves of different waveforms and periods are generated. The faster the rotation speed of the airflow regulating disc 15, the higher the output frequency of the pressure waves.

[0028] Piston assembly 14, as attached Figure 5As shown, the piston is made of high-strength alloy steel and cooperates with the airflow regulating wheel 15 and the flow guiding device 13. The piston is located in the piston chamber 18 and is slidably sealed to the housing by a dynamic sealing ring. Once the bottom area of ​​the piston is determined, a specific excitation force can be output. The top of the piston contacts the test specimen to transmit the excitation force to the test specimen. Different materials and structures of contacts can be set according to the shape of the contact surface of the test specimen.

[0029] The vibrator end cover 9 has an exhaust hole on its wall surface to discharge the gas from the piston chamber.

[0030] The pneumatic vibrator also includes a stepper motor 21, a clutch 22, and a power supply system 24 to provide power and continuous air supply. See attached diagram for its components. Figure 7 .

[0031] The device described in this invention can output step pressure and sinusoidal pressure waves of a certain frequency after the piston assembly is removed. Therefore, it can be used as a dynamic pressure source to calibrate or standardize pressure sensors.

[0032] This invention is used in a solid rocket motor test apparatus. During the engine test, an excitation force is applied to the front end face of the casing. The excitation frequencies are 100Hz, 300Hz, 500Hz, 800Hz, 1000Hz, and 1200Hz, and the excitation force is adjustable from 1 to 20kN. This shows that the invention can meet the usage requirements and make up for the shortcomings of existing exciters.

Claims

1. A pneumatic vibrator, comprising a vibrator end cap (9), an airflow regulating disc drive shaft (10), a high-pressure cylinder (12), a flow guiding device (13), a piston assembly (14), and an airflow regulating disc (15), characterized in that: One end of the airflow regulating disk drive shaft (10) is fixed inside the housing via a rotating bearing (11), and the airflow regulating disk (15) is fixed inside the housing on one end of the airflow regulating disk drive shaft (10); the other end of the airflow regulating disk drive shaft (10) located outside the housing is equipped with a drive wheel (16); The airflow regulating plate (15) is a circular turntable with a raised outer wall. An air inlet hole and an air outlet hole are respectively provided on the outer wall of the turntable. A high-pressure cylinder (12) is installed on the raised side of the outer wall of the airflow regulating plate (15). The high-pressure cylinder (12) has corresponding air holes on its cylinder wall corresponding to the air inlet holes on the outer wall of the airflow regulating plate (15). The high-pressure cylinder (12) also has an air inlet channel on its wall. Gas enters the high-pressure cylinder (12) through the air inlet channel and then enters the air inlet hole of the airflow regulating plate (15) through the air inlet hole of the high-pressure cylinder (12). Gas is discharged into the exhaust channel inside the housing through the air outlet hole of the airflow regulating plate (15). The piston assembly (14) is installed in the piston chamber (18) at the top of the housing. The piston of the piston assembly (14) is slidably sealed to the housing by a dynamic sealing ring. The top of the piston contacts the test piece to transmit the excitation force to the test piece. The flow guiding device (13) is installed on the outside of the airflow regulating plate (15) at the bottom of the piston chamber (18). The flow guiding device (13) is provided with air vents corresponding to the air inlet and air outlet on the outer wall of the airflow regulating plate (15). When the airflow regulating plate (15) rotates, the air inlet and air outlet on the airflow regulating plate (15) and the air vents on the flow guiding device (13) gradually connect. Through continuous air intake and exhaust, sinusoidal pressure waves with different waveforms and different periods are generated. The exciter end cover (9) is installed on the side of the housing opposite to the drive wheel disk (16). The wall of the exciter end cover (9) is provided with an exhaust hole for discharging the gas from the piston chamber into the exhaust channel.

2. The pneumatic vibrator according to claim 1, characterized in that: The air inlet and outlet of the airflow regulating disc (15) include L-shaped, circular and rectangular shapes.

3. The pneumatic vibrator according to claim 1, characterized in that: The piston bottom of the piston assembly (14) is arc-shaped.

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