High-speed switch valve fault identification method based on fluid noise and mechanical noise characteristics

Abstract

The application provides a high-speed switch valve fault recognition method based on fluid noise and mechanical noise characteristics, which can recognize the fault of the high-speed switch valve in the hydraulic system, first uses a PWM wave to drive the high-speed switch valve, measures the time-domain sound pressure signal of the high-speed switch valve through the sound pressure sensor placed on the side of the high-speed switch valve, and the time-domain sound pressure signal contains the characteristics of the mechanical noise and the fluid noise; compares the maximum value point, the time when the maximum value point appears, the maximum value point and the maximum value point of the theoretical time-domain sound pressure signal with those of the time-domain sound pressure signal of the high-speed switch valve to be tested to determine whether the fault occurs in the high-speed switch valve; and the application can recognize the fault according to the time-domain sound pressure characteristics of the mechanical noise and the fluid noise generated by the movement of the internal components of the high-speed switch valve in the hydraulic system, can analyze the cause of the fault, and improves the fault recognition efficiency.

Description

Technical Field

[0001] This invention relates to the field of high-speed switching valve fault identification technology, and in particular to a high-speed switching valve fault identification method based on fluid noise and mechanical noise characteristics. Background Technology

[0002] High-speed switching valves are widely used in many fields due to their small size, low cost, and flexible control. When operating without faults, a high-speed switching valve has only two states: fully open and fully closed. Driven by a high-frequency PWM signal, the valve core of the high-speed switching valve opens and closes rapidly to control flow. In practical applications, high-speed switching valves are usually connected to a valve block and arranged in a hydraulic system. In a hydraulic system, the presence of oil can cause changes in the movement state of the valve core, leading to jamming or sticking, preventing the high-speed switching valve from opening and closing normally or from keeping up with the frequency of the drive. Current technology has not yet enabled fault diagnosis of high-speed switching valves in hydraulic systems because the valve core is small and surrounded by oil, making it difficult to measure the valve core displacement by directly installing displacement sensors to determine if a fault has occurred.

[0003] During the rapid opening and closing of the valve core in a high-speed switching valve, mechanical and fluid noise are inevitably generated. Mechanical noise primarily originates from the mechanical collisions between moving and stationary parts within the valve, while fluid noise mainly stems from the fluid pressure surges caused by changes in valve cavity volume due to the valve core's movement. Driven by a periodic PWM wave, the valve core of the high-speed switching valve opens and closes rapidly and periodically, resulting in periodically varying mechanical and fluid noise. Furthermore, because the sources of mechanical and fluid noise differ, and because fluids possess viscosity, inertia, and compressibility, the timing of their generation differs, leading to different characteristics in the resulting mechanical and fluid noise.

[0004] The method described in this invention makes full use of the above-mentioned characteristics for fault identification, and can identify different types of faults. Summary of the Invention

[0005] This invention proposes a fault identification method for high-speed switching valves based on the characteristics of fluid noise and mechanical noise. According to the different contributions of mechanical noise and fluid noise to the sound pressure of high-speed switching valves, and the different times when mechanical noise and fluid noise occur, a sound pressure sensor is used to detect the time-domain sound pressure signals of mechanical noise and fluid noise in the actual hydraulic system of high-speed switching valves. Based on the above characteristics, different types of faults are identified.

[0006] The present invention adopts the following technical solution.

[0007] A fault identification method for high-speed switching valves based on fluid noise and mechanical noise characteristics is characterized by the following: the method includes the acquisition of time-domain sound pressure signals of fluid noise and mechanical noise, and also includes fault type judgment. The method first analyzes the characteristics of mechanical noise and fluid noise of high-speed switching valves based on the causes of their formation and the structural characteristics of the valves. Then, based on the analyzed characteristics of mechanical noise and fluid noise, it summarizes the characteristics of the time-domain sound pressure signals of the high-speed switching valves. Finally, the following steps are performed.

[0008] Step S100: Place the acoustic pressure sensor, which is used to measure the time-domain signal of fluid noise and mechanical noise, on one side of the high-speed switching valve;

[0009] Step S200: Drive the high-speed switching valve with a PWM wave to make the high-speed switching valve work;

[0010] Step S300: The acoustic pressure sensor acquires the time-domain acoustic pressure signal of the high-speed switching valve, and the time-domain acoustic pressure signal includes fluid noise and mechanical noise information of the high-speed switching valve;

[0011] Step S400: Analyze and extract the time-domain sound pressure signal to obtain the frequency of the time-domain sound pressure signal, as well as the maximum and maximum values ​​of the time-domain signal within one period, and mark the times when the maximum and maximum values ​​occur;

[0012] Step S500: Compare the frequency of the time-domain sound pressure signal with the frequency of the PWM wave, evaluate the time when the maximum value and maximum value of the time-domain sound pressure signal occur, and then determine whether the high-speed switching valve has malfunctioned.

[0013] The acoustic pressure sensor is placed on the side of the high-speed switching valve, and the axis of the acoustic pressure sensor is perpendicular to the axis of the high-speed switching valve. The acoustic pressure sensor records the mechanical noise generated by the collision between the movable and fixed parts of the high-speed switching valve, and at the same time records the fluid noise caused by the pressure impact of the fluid inside the valve chamber.

[0014] The basis for determining the fault type includes a comparison between the time-domain sound pressure signal of the high-speed switching valve collected by the sound pressure sensor and the theoretical time-domain sound pressure signal.

[0015] The mechanical noise is generated as follows: When the high-speed switching valve is working, the internal movable and fixed parts collide, thereby generating mechanical noise; including: at the moment the valve port is closed, the internal movable and fixed parts of the high-speed switching valve immediately collide, generating mechanical noise one; when the valve port is at its maximum opening, the internal movable and fixed parts of the high-speed switching valve collide, generating mechanical noise two.

[0016] The fluid noise is generated as follows: the high-speed switching valve causes a fluid pressure shock at the moment of opening and closing, thereby generating fluid noise; including: the high-speed switching valve transmits fluids with inertia, viscosity, and compressibility; at the moment the valve is closed, the fluid pressure shock has not yet reached its maximum; when the fluid pressure shock reaches its maximum, fluid noise one is generated; when the high-speed switching valve is closed, the occurrence of fluid noise one lags behind mechanical noise one; at the moment the valve is opened, high-pressure fluid immediately flows through the narrow valve opening, causing a fluid pressure shock and generating fluid noise two; the high-speed switching valve requires a certain amount of time from the moment of opening to the moment the valve is at its maximum opening; when the valve is open, the occurrence of mechanical noise two lags behind fluid noise two.

[0017] Based on the different times when mechanical noise and fluid noise occur, and the different contributions of mechanical noise and fluid noise to the sound pressure level, the sound pressure level curve of the high-speed switching valve has one maximum point and three maximum points. The maximum point corresponds to the mechanical noise one generated at the moment the valve is closed, the first maximum point corresponds to the fluid noise one when the valve is closed, the second maximum point corresponds to the fluid noise two at the moment the valve is opened, and the third maximum point corresponds to the mechanical noise two when the valve is fully opened.

[0018] In high-speed switching valves, the factors affecting the theoretical time-domain sound pressure signal include mechanical noise characteristics and fluid noise characteristics;

[0019] The theoretical time-domain sound pressure signal includes the times when mechanical noise and fluid noise occur, and the contribution of mechanical noise and fluid noise to the total noise;

[0020] The mechanical noise and fluid noise contribute differently to the total noise, causing the theoretical time-domain sound pressure signal to have a maximum and a maximum value.

[0021] The mechanical noise and fluid noise occur at different times, causing the theoretical time-domain sound pressure signal to reach its maximum and maxima at different times.

[0022] Based on the difference in the contribution of mechanical noise and fluid noise to the theoretical time-domain sound pressure signal, as well as the time difference in the generation of mechanical noise and fluid noise, the theoretical time-domain sound pressure signal of the high-speed switching valve exhibits four large sound pressure amplitudes within one cycle. The largest sound pressure amplitude is the maximum value of the theoretical time-domain sound pressure signal, and the other three sound pressure amplitudes are the maximum values ​​of the theoretical time-domain sound pressure signal, namely, the first maximum value of the time-domain sound pressure signal, the second maximum value of the time-domain sound pressure signal, and the third maximum value of the time-domain sound pressure signal.

[0023] The theoretical time-domain sound pressure signal is compared with the time-domain sound pressure signal of the high-speed switching valve. If the theoretical time-domain sound pressure signal is consistent with the time-domain sound pressure signal of the high-speed switching valve, it indicates that the high-speed switching valve is fault-free. If they are inconsistent, it indicates that the high-speed switching valve is faulty.

[0024] The high-speed switching valve event corresponding to the time of the generation of the maximum value of the time-domain sound pressure signal is: the mechanical collision between the movable part and the fixed part inside the high-speed switching valve at the instant the valve port closes.

[0025] The high-speed switching valve event corresponding to the time-domain sound pressure maximum value is due to the fluid pressure impact when the valve port of the high-speed switching valve closes; in this event, at the instant the valve port closes, due to the existence of fluid inertia, viscosity and compressibility, the fluid pressure impact at the moment the valve port closes lags behind the mechanical collision.

[0026] The high-speed switching valve event corresponding to the second maximum time-domain sound pressure is due to the fluid pressure shock at the moment the valve port of the high-speed switching valve opens. In this event, at the moment the valve port opens, the oil flows through the narrow valve port, which will cause a fluid pressure shock. It takes a certain amount of time from the moment the valve port opens to the moment the valve port is fully opened, which causes the mechanical collision at the moment the valve port opens to occur to lag behind the fluid pressure shock.

[0027] The high-speed switching valve event corresponding to the time-domain sound pressure maximum value three is due to the mechanical collision between the movable and fixed parts inside the high-speed switching valve when the valve port is fully open and at its maximum opening.

[0028] The fault types of the high-speed switching valve include the valve port failing to open, the valve port failing to close, and the valve core opening and closing frequency being inconsistent with the driving PWM wave frequency.

[0029] The fault characteristic of the valve port failing to open is that the time-domain sound pressure signal is flat and has no maximum value;

[0030] The fault characteristic of the valve port failing to close is that the time-domain sound pressure signal has only one maximum value;

[0031] The fault diagnosis characteristic of the valve core opening and closing frequency being inconsistent with the driving PWM wave frequency is that the time-domain sound pressure signal has one maximum value and three maximum values, but the frequency of the time-domain sound pressure signal is inconsistent with the frequency of the PWM wave.

[0032] The high-speed switching valve is a normally open high-speed switching valve.

[0033] The normally open high-speed switching valve includes a housing (1), a gasket (2), an electromagnetic coil (3), an armature (4), a push rod (5), a valve core (6), a valve seat (7), a return spring (8), an oil inlet chamber (9), an oil inlet P, and a working port A;

[0034] When the high-speed switching valve is working, the electromagnetic coil generates electromagnetic force under the drive of the PWM wave, which pushes the armature to move. The armature pushes the push rod to move, and the push rod pushes the valve core to move. When the valve core hits the valve seat, the valve port closes. Under the action of fluid force and spring force, the valve port opens. When the armature hits the gasket, the valve port is fully opened.

[0035] The return spring ensures that the armature, push rod, and valve core are always in contact.

[0036] The mechanical noise generation points of the high-speed switching valve include the contact points between the armature and the gasket, the armature and the push rod, the push rod and the valve core, and the valve core and the valve seat. When the valve is closed, since the collision occurs instantaneously, the contact points between the armature and the push rod collide (a1), the contact points between the push rod and the valve core collide (a2), and the contact points between the valve core and the valve seat collide (a3). These three collisions occur simultaneously and generate mechanical noise. At the same time, when the valve is closed, the inlet cavity undergoes a drastic change, generating fluid pressure impact (a4) within the valve cavity, generating fluid noise one. Collisions occur instantaneously when the valve is fully open, specifically, the contact points between the valve core and the push rod collide (b3), the contact points between the push rod and the armature collide (b2), and the contact points between the armature and the gasket collide (b1). These three collisions occur simultaneously and generate mechanical noise. At the same time, when the valve is open, high-pressure oil flows through the narrow gap of the valve, generating fluid pressure impact (b4), generating fluid noise two.

[0037] Based on the different contributions of mechanical noise and fluid noise to the sound pressure of high-speed switching valves, and the different times when mechanical noise and fluid noise occur, this invention uses a sound pressure sensor to detect the time-domain sound pressure signals of mechanical noise and fluid noise in actual hydraulic systems. This invention can fully utilize the above signal characteristics to identify different types of faults, which helps to realize fault diagnosis of high-speed switching valves in hydraulic systems.

[0038] This invention can identify faults based on the time-domain sound pressure characteristics of mechanical noise and fluid noise generated by the movement of internal components when a high-speed switching valve operates in a hydraulic system, and can analyze the causes of faults, thereby improving fault identification efficiency. Attached Figure Description

[0039] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0040] Appendix Figure 1 This is a preferred embodiment of the high-speed switching valve fault identification technology solution of the present invention;

[0041] Appendix Figure 2 This is a schematic diagram of the placement of the sound pressure sensor according to a preferred embodiment of the present invention (A1 is the sound pressure sensor, A2 is the switching valve).

[0042] Appendix Figure 3This is a schematic diagram of the high-speed switching valve structure according to a preferred embodiment of the present invention;

[0043] Appendix Figure 4 This is a schematic diagram showing the locations where mechanical and fluid noise are generated when the valve is closed according to a preferred embodiment of the present invention.

[0044] Appendix Figure 5 A preferred embodiment of the present invention is a schematic diagram showing the locations where mechanical noise and fluid noise are generated when the valve is opened;

[0045] Appendix Figure 6 This is a schematic diagram of the time-domain sound pressure of mechanical noise and fluid noise according to a preferred embodiment of the present invention;

[0046] In the diagram: outer casing (1), gasket (2), electromagnetic coil (3), armature (4), push rod (5), valve core (6), valve seat (7), return spring (8), oil inlet cavity (9), oil inlet P, working port A. Detailed Implementation

[0047] As shown in the figure, a fault identification method for high-speed switching valves based on fluid noise and mechanical noise characteristics is characterized by: the method including the acquisition of time-domain sound pressure signals of fluid noise and mechanical noise, and fault type judgment. The method first analyzes the characteristics of mechanical noise and fluid noise of high-speed switching valves based on the causes of mechanical noise and fluid noise formation and the structural characteristics of high-speed switching valves, and then summarizes the characteristics of time-domain sound pressure signals of high-speed switching valves based on the analyzed characteristics of mechanical noise and fluid noise; then, the following steps are performed.

[0048] Step S100: Place the acoustic pressure sensor, which is used to measure the time-domain signal of fluid noise and mechanical noise, on one side of the high-speed switching valve;

[0049] Step S200: Drive the high-speed switching valve with a PWM wave to make the high-speed switching valve work;

[0050] Step S300: The acoustic pressure sensor acquires the time-domain acoustic pressure signal of the high-speed switching valve, and the time-domain acoustic pressure signal includes fluid noise and mechanical noise information of the high-speed switching valve;

[0051] Step S400: Analyze and extract the time-domain sound pressure signal to obtain the frequency of the time-domain sound pressure signal, as well as the maximum and maximum values ​​of the time-domain signal within one period, and mark the times when the maximum and maximum values ​​occur;

[0052] Step S500: Compare the frequency of the time-domain sound pressure signal with the frequency of the PWM wave, evaluate the time when the maximum value and maximum value of the time-domain sound pressure signal occur, and then determine whether the high-speed switching valve has malfunctioned.

[0053] The acoustic pressure sensor is placed on the side of the high-speed switching valve, and the axis of the acoustic pressure sensor is perpendicular to the axis of the high-speed switching valve. The acoustic pressure sensor records the mechanical noise generated by the collision between the movable and fixed parts of the high-speed switching valve, and at the same time records the fluid noise caused by the pressure impact of the fluid inside the valve chamber.

[0054] The basis for determining the fault type includes a comparison between the time-domain sound pressure signal of the high-speed switching valve collected by the sound pressure sensor and the theoretical time-domain sound pressure signal.

[0055] The mechanical noise is generated as follows: When the high-speed switching valve is working, the internal movable and fixed parts collide, thereby generating mechanical noise; including: at the moment the valve port is closed, the internal movable and fixed parts of the high-speed switching valve immediately collide, generating mechanical noise one; when the valve port is at its maximum opening, the internal movable and fixed parts of the high-speed switching valve collide, generating mechanical noise two.

[0056] The fluid noise is generated as follows: the high-speed switching valve causes a fluid pressure shock at the moment of opening and closing, thereby generating fluid noise; including: the high-speed switching valve transmits fluids with inertia, viscosity, and compressibility; at the moment the valve is closed, the fluid pressure shock has not yet reached its maximum; when the fluid pressure shock reaches its maximum, fluid noise one is generated; when the high-speed switching valve is closed, the occurrence of fluid noise one lags behind mechanical noise one; at the moment the valve is opened, high-pressure fluid immediately flows through the narrow valve opening, causing a fluid pressure shock and generating fluid noise two; the high-speed switching valve requires a certain amount of time from the moment of opening to the moment the valve is at its maximum opening; when the valve is open, the occurrence of mechanical noise two lags behind fluid noise two.

[0057] Based on the different times when mechanical noise and fluid noise occur, and the different contributions of mechanical noise and fluid noise to the sound pressure level, the sound pressure level curve of the high-speed switching valve has one maximum point and three maximum points. The maximum point corresponds to the mechanical noise one generated at the moment the valve is closed, the first maximum point corresponds to the fluid noise one when the valve is closed, the second maximum point corresponds to the fluid noise two at the moment the valve is opened, and the third maximum point corresponds to the mechanical noise two when the valve is fully opened.

[0058] In high-speed switching valves, the factors affecting the theoretical time-domain sound pressure signal include mechanical noise characteristics and fluid noise characteristics;

[0059] The theoretical time-domain sound pressure signal includes the times when mechanical noise and fluid noise occur, and the contribution of mechanical noise and fluid noise to the total noise;

[0060] The mechanical noise and fluid noise contribute differently to the total noise, causing the theoretical time-domain sound pressure signal to have a maximum and a maximum value.

[0061] The mechanical noise and fluid noise occur at different times, causing the theoretical time-domain sound pressure signal to reach its maximum and maxima at different times.

[0062] Based on the difference in the contribution of mechanical noise and fluid noise to the theoretical time-domain sound pressure signal, as well as the time difference in the generation of mechanical noise and fluid noise, the theoretical time-domain sound pressure signal of the high-speed switching valve exhibits four large sound pressure amplitudes within one cycle. The largest sound pressure amplitude is the maximum value of the theoretical time-domain sound pressure signal, and the other three sound pressure amplitudes are the maximum values ​​of the theoretical time-domain sound pressure signal, namely, the first maximum value of the time-domain sound pressure signal, the second maximum value of the time-domain sound pressure signal, and the third maximum value of the time-domain sound pressure signal.

[0063] The theoretical time-domain sound pressure signal is compared with the time-domain sound pressure signal of the high-speed switching valve. If the theoretical time-domain sound pressure signal is consistent with the time-domain sound pressure signal of the high-speed switching valve, it indicates that the high-speed switching valve is fault-free. If they are inconsistent, it indicates that the high-speed switching valve is faulty.

[0064] The high-speed switching valve event corresponding to the time of the generation of the maximum value of the time-domain sound pressure signal is: the mechanical collision between the movable part and the fixed part inside the high-speed switching valve at the instant the valve port closes.

[0065] The high-speed switching valve event corresponding to the time-domain sound pressure maximum value is due to the fluid pressure impact when the valve port of the high-speed switching valve closes; in this event, at the instant the valve port closes, due to the existence of fluid inertia, viscosity and compressibility, the fluid pressure impact at the moment the valve port closes lags behind the mechanical collision.

[0066] The high-speed switching valve event corresponding to the second maximum time-domain sound pressure is due to the fluid pressure shock at the moment the valve port of the high-speed switching valve opens. In this event, at the moment the valve port opens, the oil flows through the narrow valve port, which will cause a fluid pressure shock. It takes a certain amount of time from the moment the valve port opens to the moment the valve port is fully opened, which causes the mechanical collision at the moment the valve port opens to occur to lag behind the fluid pressure shock.

[0067] The high-speed switching valve event corresponding to the time-domain sound pressure maximum value three is due to the mechanical collision between the movable and fixed parts inside the high-speed switching valve when the valve port is fully open and at its maximum opening.

[0068] The fault types of the high-speed switching valve include the valve port failing to open, the valve port failing to close, and the valve core opening and closing frequency being inconsistent with the driving PWM wave frequency.

[0069] The fault characteristic of the valve port failing to open is that the time-domain sound pressure signal is flat and has no maximum value;

[0070] The fault characteristic of the valve port failing to close is that the time-domain sound pressure signal has only one maximum value;

[0071] The fault diagnosis characteristic of the valve core opening and closing frequency being inconsistent with the driving PWM wave frequency is that the time-domain sound pressure signal has one maximum value and three maximum values, but the frequency of the time-domain sound pressure signal is inconsistent with the frequency of the PWM wave.

[0072] The high-speed switching valve is a normally open high-speed switching valve.

[0073] The normally open high-speed switching valve includes a housing 1, a gasket 2, an electromagnetic coil 3, an armature 4, a push rod 5, a valve core 6, a valve seat 7, a return spring 8, an oil inlet chamber 9, an oil inlet P, and a working port A;

[0074] When the high-speed switching valve is working, the electromagnetic coil generates electromagnetic force under the drive of the PWM wave, which pushes the armature to move. The armature pushes the push rod to move, and the push rod pushes the valve core to move. When the valve core hits the valve seat, the valve port closes. Under the action of fluid force and spring force, the valve port opens. When the armature hits the gasket, the valve port is fully opened.

[0075] The return spring ensures that the armature, push rod, and valve core are always in contact.

[0076] The mechanical noise generation points of the high-speed switching valve include the contact points between the armature and the gasket, the armature and the push rod, the push rod and the valve core, and the valve core and the valve seat. When the valve is closed, since the collision occurs instantaneously, the contact points between the armature and the push rod collide (a1), the contact points between the push rod and the valve core collide (a2), and the contact points between the valve core and the valve seat collide (a3). These three collisions occur simultaneously and generate mechanical noise. At the same time, when the valve is closed, the inlet cavity undergoes a drastic change, generating fluid pressure impact (a4) within the valve cavity, generating fluid noise one. Collisions occur instantaneously when the valve is fully open, specifically, the contact points between the valve core and the push rod collide (b3), the contact points between the push rod and the armature collide (b2), and the contact points between the armature and the gasket collide (b1). These three collisions occur simultaneously and generate mechanical noise. At the same time, when the valve is open, high-pressure oil flows through the narrow gap of the valve, generating fluid pressure impact (b4), generating fluid noise two.

[0077] Example:

[0078] In this example, the technical solution is as follows: Figure 1 As shown.

[0079] Based on the aforementioned fault identification method, the fault detection steps include:

[0080] The high-speed switching valve is excited by a PWM wave voltage to make it work.

[0081] The acoustic pressure sensor used to measure fluid noise and mechanical noise is placed on one side of the high-speed switching valve; for example... Figure 2 As shown, the sound pressure sensor A1 is placed on the side of the high-speed switching valve A2, and the axial direction of the sound pressure sensor is perpendicular to the axial direction of the high-speed switching valve. The sound pressure sensor records the mechanical noise generated by the collision between the movable and fixed parts of the high-speed switching valve, and at the same time records the fluid noise caused by the pressure impact of the fluid inside the valve chamber.

[0082] The acoustic pressure sensor acquires the time-domain acoustic pressure signal of the high-speed switching valve, and the time-domain acoustic pressure signal of the high-speed switching valve includes fluid noise and mechanical noise information of the high-speed switching valve;

[0083] The time-domain sound pressure signal is analyzed and extracted to obtain the frequency of the time-domain sound pressure signal, as well as the maximum and maximum values ​​of the signal within one period, and the times when the maximum and maximum values ​​occur are marked.

[0084] The frequency of the obtained time-domain sound pressure signal is compared with the frequency of the driving PWM wave. If the frequency of the time-domain sound pressure signal is inconsistent with the frequency of the driving PWM wave, but the time-domain sound pressure signal has one maximum value and three maximum values, then the fault type is that the valve core opening and closing frequency is inconsistent with the driving PWM wave frequency.

[0085] If the obtained sound pressure signal is not periodic and the time-domain sound pressure signal is flat with no maximum value, then the fault type is that the valve port cannot be opened.

[0086] If the obtained sound pressure signal is not periodic but has a maximum value, then the fault type valve port cannot be closed.

[0087] The structural diagram of the high-speed switching valve is as follows: Figure 3 As shown, the normally open high-speed switching valve includes a housing 1, a gasket 2, an electromagnetic coil 3, an armature 4, a push rod 5, a valve core 6, a valve seat 7, a return spring 8, an oil inlet chamber 9, an oil inlet P, and a working port A;

[0088] When the high-speed switching valve is working, the electromagnetic coil generates electromagnetic force under the drive of the PWM wave, which pushes the armature to move. The armature pushes the push rod to move, and the push rod pushes the valve core to move. When the valve core hits the valve seat, the valve port closes. Under the action of fluid force and spring force, the valve port opens. When the armature hits the gasket, the valve port is fully opened.

[0089] The return spring keeps the armature, push rod, and valve core in contact at all times. Mechanical noise is mainly generated at the contact points between the armature and the gasket, the armature and the push rod, the push rod and the valve core, and the valve core and the valve seat. Figure 4As shown, when the valve is closed, because the collision occurs instantaneously, collisions occur at three points: a1 between the armature and the push rod, a2 between the push rod and the valve core, and a3 between the valve core and the valve seat. These three collisions occur simultaneously and generate mechanical noise. At the same time, when the valve is closed, the inlet chamber undergoes a drastic change in volume, generating fluid pressure impact a4 within the valve chamber, thus producing the first fluid noise. Figure 5 As shown, when the valve port is fully open, the collision occurs in an instant. The valve core collides with the push rod at the contact point b3, the push rod collides with the armature at the contact point b2, and the armature collides with the gasket at the contact point b1. The three collisions occur simultaneously and generate mechanical noise. At the same time, when the valve port is open, the high-pressure oil flows through the narrow gap of the valve port, generating fluid pressure impact b4, which generates a second fluid noise.

[0090] like Figure 6 As shown, the sound pressure signal contains a first mechanical noise A, a first fluid noise B, a second fluid noise C, and a second mechanical noise D. Specifically, the sound pressure signal will have one maximum point and three maximum points. The time when the maximum point occurs corresponds to the first mechanical noise A, the time when the first maximum point occurs corresponds to the first fluid noise B, the time when the second maximum point occurs corresponds to the second fluid noise C, and the time when the third maximum point occurs corresponds to the second mechanical noise D.

[0091] In this example, the theoretical time-domain sound pressure signal data used for fault diagnosis is obtained based on the hardware design characteristics of the high-speed switching valve, either provided by the manufacturer or collected by conducting high-speed on / off tests on a newly purchased high-speed switching valve.

Claims

1. A high-speed switching valve fault identification method based on fluid noise and mechanical noise characteristics, characterized in that: The method includes the acquisition of time-domain sound pressure signals of fluid noise and mechanical noise, and also includes fault type judgment. The method first analyzes the characteristics of mechanical noise and fluid noise of high-speed switching valve based on the causes of mechanical noise and fluid noise formation and the structural characteristics of high-speed switching valve, and then summarizes the characteristics of time-domain sound pressure signals of high-speed switching valve based on the analyzed characteristics of mechanical noise and fluid noise; then the following steps are performed. Step S100: Place the acoustic pressure sensor, which is used to measure the time-domain signal of fluid noise and mechanical noise, on one side of the high-speed switching valve; Step S200: Drive the high-speed switching valve with a PWM wave to make the high-speed switching valve work; Step S300: The acoustic pressure sensor acquires the time-domain acoustic pressure signal of the high-speed switching valve, and the time-domain acoustic pressure signal includes fluid noise and mechanical noise information of the high-speed switching valve; Step S400: Analyze and extract the time-domain sound pressure signal to obtain the frequency of the time-domain sound pressure signal, as well as the maximum and maximum values ​​of the time-domain signal within one period, and mark the times when the maximum and maximum values ​​occur; Step S500: Compare the frequency of the time-domain sound pressure signal with the frequency of the PWM wave, evaluate the time when the maximum value and maximum value of the time-domain sound pressure signal occur, and then determine whether the high-speed switching valve has malfunctioned. The basis for determining the fault type includes a comparison between the time-domain sound pressure signal of the high-speed switching valve collected by the sound pressure sensor and the theoretical time-domain sound pressure signal. The mechanical noise is generated as follows: When the high-speed switching valve is working, the internal movable and fixed parts collide, thereby generating mechanical noise; including: at the moment the valve port is closed, the internal movable and fixed parts of the high-speed switching valve immediately collide, generating mechanical noise one; when the valve port is at its maximum opening, the internal movable and fixed parts of the high-speed switching valve collide, generating mechanical noise two. The fluid noise is generated as follows: the high-speed switching valve causes a fluid pressure shock at the moment of opening and closing, thereby generating fluid noise; including: the high-speed switching valve transmits fluids with inertia, viscosity, and compressibility; at the moment the valve is closed, the fluid pressure shock has not yet reached its maximum; when the fluid pressure shock reaches its maximum, fluid noise one is generated; when the high-speed switching valve is closed, the occurrence of fluid noise one lags behind mechanical noise one; at the moment the valve is opened, high-pressure fluid immediately flows through the narrow valve opening, causing a fluid pressure shock and generating fluid noise two; the high-speed switching valve requires a certain amount of time from the moment of opening to the moment the valve is at its maximum opening; when the valve is open, the occurrence of mechanical noise two lags behind fluid noise two. Based on the different times when mechanical noise and fluid noise occur, and the different contributions of mechanical noise and fluid noise to the sound pressure level, the sound pressure level curve of the high-speed switching valve has one maximum point and three maximum points. The maximum point corresponds to the mechanical noise one generated at the moment the valve is closed, the first maximum point corresponds to the fluid noise one when the valve is closed, the second maximum point corresponds to the fluid noise two at the moment the valve is opened, and the third maximum point corresponds to the mechanical noise two when the valve is fully opened. In high-speed switching valves, the factors affecting the theoretical time-domain sound pressure signal include mechanical noise characteristics and fluid noise characteristics; The theoretical time-domain sound pressure signal includes the times when mechanical noise and fluid noise occur, and the contribution of mechanical noise and fluid noise to the total noise; The mechanical noise and fluid noise contribute differently to the total noise, causing the theoretical time-domain sound pressure signal to have a maximum and a maximum value. The mechanical noise and fluid noise occur at different times, causing the theoretical time-domain sound pressure signal to reach its maximum and maxima at different times. Based on the difference in the contribution of mechanical noise and fluid noise to the theoretical time-domain sound pressure signal, as well as the time difference in the generation of mechanical noise and fluid noise, the theoretical time-domain sound pressure signal of the high-speed switching valve exhibits four large sound pressure amplitudes within one cycle. The largest sound pressure amplitude is the maximum value of the theoretical time-domain sound pressure signal, and the other three sound pressure amplitudes are the maximum values ​​of the theoretical time-domain sound pressure signal, namely, the first maximum value of the time-domain sound pressure signal, the second maximum value of the time-domain sound pressure signal, and the third maximum value of the time-domain sound pressure signal. The theoretical time-domain sound pressure signal is compared with the time-domain sound pressure signal of the high-speed switching valve. If the theoretical time-domain sound pressure signal is consistent with the time-domain sound pressure signal of the high-speed switching valve, it indicates that the high-speed switching valve is fault-free. If they are inconsistent, it indicates that the high-speed switching valve is faulty. The high-speed switching valve event corresponding to the time of the generation of the maximum value of the time-domain sound pressure signal is: the mechanical collision between the movable part and the fixed part inside the high-speed switching valve at the instant the valve port closes. The high-speed switching valve event corresponding to the time-domain sound pressure maximum value is due to the fluid pressure impact when the valve port of the high-speed switching valve closes; in this event, at the instant the valve port closes, due to the existence of fluid inertia, viscosity and compressibility, the fluid pressure impact at the moment the valve port closes lags behind the mechanical collision. The high-speed switching valve event corresponding to the second maximum time-domain sound pressure is due to the fluid pressure shock at the moment the valve port of the high-speed switching valve opens. In this event, at the moment the valve port opens, the oil flows through the narrow valve port, which will cause a fluid pressure shock. It takes a certain amount of time from the moment the valve port opens to the moment the valve port is fully opened, which causes the mechanical collision at the moment the valve port opens to occur to lag behind the fluid pressure shock. The high-speed switching valve event corresponding to the third maximum time-domain sound pressure value is due to the mechanical collision between the movable and fixed parts inside the high-speed switching valve when the valve port is fully open and at its maximum opening. The fault types of the high-speed switching valve include the valve port failing to open, the valve port failing to close, and the valve core opening and closing frequency being inconsistent with the driving PWM wave frequency. The fault characteristic of the valve port failing to open is that the time-domain sound pressure signal is flat and has no maximum value; The fault characteristic of the valve port failing to close is that the time-domain sound pressure signal has only one maximum value; The fault diagnosis characteristic of the valve core opening and closing frequency being inconsistent with the driving PWM wave frequency is that the time-domain sound pressure signal has one maximum value and three maximum values, but the frequency of the time-domain sound pressure signal is inconsistent with the frequency of the PWM wave.

2. The high-speed switching valve fault identification method based on fluid noise and mechanical noise characteristics according to claim 1, characterized in that: The acoustic pressure sensor is placed on the side of the high-speed switching valve, and the axis of the acoustic pressure sensor is perpendicular to the axis of the high-speed switching valve. The acoustic pressure sensor records the mechanical noise generated by the collision between the movable and fixed parts of the high-speed switching valve, and at the same time records the fluid noise caused by the pressure impact of the fluid inside the valve chamber.

3. The high-speed switching valve fault identification method based on fluid noise and mechanical noise characteristics according to claim 1, characterized in that: The high-speed switching valve is a normally open high-speed switching valve.

4. The high-speed switching valve fault identification method based on fluid noise and mechanical noise characteristics according to claim 3, characterized in that: The normally open high-speed switching valve includes a housing (1), a gasket (2), an electromagnetic coil (3), an armature (4), a push rod (5), a valve core (6), a valve seat (7), a return spring (8), an oil inlet chamber (9), an oil inlet P, and a working port A; When the high-speed switching valve is working, the electromagnetic coil generates electromagnetic force under the drive of the PWM wave, which pushes the armature to move. The armature pushes the push rod to move, and the push rod pushes the valve core to move. When the valve core hits the valve seat, the valve port closes. Under the action of fluid force and spring force, the valve port opens. When the armature hits the gasket, the valve port is fully opened. The return spring ensures that the armature, push rod, and valve core are always in contact. The mechanical noise generation points of the high-speed switching valve include the contact points between the armature and the gasket, the armature and the push rod, the push rod and the valve core, and the valve core and the valve seat. When the valve is closed, since the collision occurs instantaneously, the contact points between the armature and the push rod collide (a1), the contact points between the push rod and the valve core collide (a2), and the contact points between the valve core and the valve seat collide (a3). These three collisions occur simultaneously and generate mechanical noise. At the same time, when the valve is closed, the inlet cavity undergoes a drastic change, generating fluid pressure impact (a4) within the valve cavity, generating fluid noise one. Collisions occur instantaneously when the valve is fully open, specifically, the contact points between the valve core and the push rod collide (b3), the contact points between the push rod and the armature collide (b2), and the contact points between the armature and the gasket collide (b1). These three collisions occur simultaneously and generate mechanical noise. At the same time, when the valve is open, high-pressure oil flows through the narrow gap of the valve, generating fluid pressure impact (b4), generating fluid noise two.

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