CN116608318A - High-speed switch valve fault identification method based on fluid noise and mechanical noise characteristics - Google Patents

Abstract

The invention provides a high-speed switch valve fault identification method based on fluid noise and mechanical noise characteristics, which can realize the identification of faults of a high-speed switch valve when the high-speed switch valve works in a hydraulic system. Judging whether the inside of the high-speed switch valve is faulty or not by comparing the theoretical time domain sound pressure signal with the maximum value point and the moment of occurrence of the maximum value point of the time domain sound pressure signal of the high-speed switch valve to be tested and the magnitudes of the maximum value point and the maximum value point; the invention can carry out fault identification according to the time domain sound pressure characteristics of mechanical noise and fluid noise generated by the movement of internal parts when the high-speed switch valve works in the hydraulic system, can analyze the cause of the fault and improves the fault identification efficiency.

Description

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

Technical Field

The invention relates to the technical field of high-speed switch valve fault identification, in particular to a high-speed switch valve fault identification method based on fluid noise and mechanical noise characteristics.

Background

The high-speed switch valve has wide application in various fields due to the characteristics of small volume, low cost, flexible control and the like. When the high-speed switching valve works without faults, the valve core of the high-speed switching valve is driven by a high-frequency PWM signal to be quickly opened and closed, so that the flow is controlled. High-speed switching valves are usually connected to a valve block in actual use, arranged in a hydraulic system. In a hydraulic system, the movement state of a valve core can be changed due to the existence of oil, and the phenomenon of blocking or stagnation occurs, so that a high-speed switch valve cannot be normally opened or closed or cannot keep up with the frequency of a driving model. The prior art does not realize fault diagnosis of the high-speed switch valve in a hydraulic system, because the volume of the high-speed switch valve is small, the valve core is surrounded by oil, and the valve core displacement of the high-speed switch valve is difficult to measure by a method of directly installing a displacement sensor and the like, so that whether the fault occurs or not is judged.

Mechanical noise and fluid noise are inevitably generated in the process of quick opening and closing of the valve core of the high-speed switch valve, the mechanical noise mainly comes from mechanical collision between a movable part and a fixed part in the high-speed switch valve, and the fluid noise mainly comes from fluid pressure impact caused by valve cavity volume change caused by valve core movement. Under the drive of periodic PWM wave, the valve core of the high-speed switch valve can be opened and closed periodically and rapidly, and periodic variation mechanical noise and fluid noise are brought. And because the sources of the mechanical noise and the fluid noise are different, and the fluid has viscosity, inertia and compressibility, the time for generating the mechanical noise and the fluid noise is different, and the characteristics of the generated mechanical noise and the fluid noise are different.

The method of the invention makes full use of the characteristics to identify faults and can identify faults of different types.

Disclosure of Invention

The invention provides a high-speed switch valve fault identification method based on the characteristics of fluid noise and mechanical noise, which adopts a sound pressure sensor to detect time domain sound pressure signals of the mechanical noise and the fluid noise of a high-speed switch valve in an actual hydraulic system according to different sound pressure contribution amounts of the mechanical noise and the fluid noise to the high-speed switch valve and different occurrence moments of the mechanical noise and the fluid noise, and carries out fault identification on different types of faults according to the characteristics.

The invention adopts the following technical scheme.

The high-speed switch valve fault identification method based on the characteristics of fluid noise and mechanical noise is characterized by comprising the following steps of: the method comprises the steps of collecting time domain sound pressure signals of fluid noise and mechanical noise and judging fault types, wherein the method firstly analyzes the characteristics of the mechanical noise and the fluid noise of the high-speed switch valve according to the reasons formed by the mechanical noise and the fluid noise of the high-speed switch valve and by combining the structural characteristics of the high-speed switch valve, and then summarizes the characteristics of the time domain sound pressure signals of the high-speed switch valve based on the analyzed characteristics of the mechanical noise and the fluid noise; then the following steps are performed;

step S100: placing an acoustic pressure sensor for measuring time domain signals of fluid noise and mechanical noise on one side of the high-speed switching valve;

step S200: PWM wave driving is carried out on the high-speed switching valve, so that the high-speed switching valve works;

step S300: the sound pressure sensor collects a time domain sound pressure signal of the high-speed switching valve, and the time domain sound pressure signal contains fluid noise and mechanical noise information of the high-speed switching valve;

step S400: analyzing and extracting the time domain sound pressure signal to obtain the frequency of the time domain sound pressure signal, the maximum value and the maximum value of the time domain signal in one period, and marking the occurrence time of the maximum value and the maximum value;

step S500: comparing the frequency of the time domain sound pressure signal with the frequency of the PWM wave, evaluating the time when the maximum value and the maximum value of the time domain sound pressure signal appear, and further judging whether the high-speed switch valve fails or not.

The sound pressure sensor is arranged on the side edge of the high-speed switch valve, the axial direction of the sound pressure sensor is perpendicular to the axial direction of the high-speed switch valve, and the sound pressure sensor records mechanical noise generated by collision between a movable part and a fixed part of the high-speed switch valve and records fluid noise caused by fluid pressure impact in the valve cavity.

The basis for judging the fault type comprises comparison of the time domain sound pressure signal acquired by the sound pressure sensor and the theoretical time domain sound pressure signal.

The mechanical noise is generated because: when the high-speed switch valve works, collision occurs between the movable part and the fixed part in the high-speed switch valve, so that mechanical noise is generated; comprising the following steps: at the moment of closing the valve port, the movable part and the fixed part in the high-speed switch valve immediately collide mechanically to generate first mechanical noise; when the valve port is at the maximum opening, the movable part and the fixed part in the high-speed switch valve collide to generate mechanical noise II;

the fluid noise is generated as follows: the valve port of the high-speed switch valve triggers fluid pressure impact at the moment of opening and closing, thereby generating fluid noise; comprising the following steps: the high-speed switch valve transmits fluid with inertia, viscosity and compressibility, fluid pressure impact is not maximum at the moment of closing the valve port, and fluid noise I is generated when the fluid pressure impact reaches the maximum; when the valve port of the high-speed switch valve is closed, the first occurrence time of the fluid noise lags behind the first mechanical noise; at the moment of opening the valve port, high-pressure fluid immediately flows through a narrow valve port, so that fluid pressure impact is caused, and second fluid noise is generated; the valve port of the high-speed switching valve needs a certain time period from the moment of opening to the moment of the maximum opening of the valve port, and when the valve port is opened, the moment of occurrence of mechanical noise II lags behind fluid noise II;

according to different occurrence moments of mechanical noise and fluid noise, and different contributions of the mechanical noise and the fluid noise to sound pressure levels, a maximum value point appears on a sound pressure level curve of the high-speed switch valve, wherein the three maximum value points correspond to mechanical noise I generated at the moment of closing a valve port, the maximum value point I corresponds to fluid noise I at the moment of closing the valve port, the maximum value point II corresponds to fluid noise II at the moment of opening the valve port, and the maximum value point III corresponds to mechanical noise II at the moment of completely opening the valve port;

in the high-speed switch valve, factors affecting the theoretical time-domain acoustic pressure signal include mechanical noise characteristics and fluid noise characteristics;

the theoretical time domain sound pressure signal comprises the time at which mechanical noise and fluid noise appear, and the contribution degree of the mechanical noise and the fluid noise to the total noise;

the contribution degree of the mechanical noise and the fluid noise to the total noise is different, and the theoretical time domain sound pressure signal has a maximum value and a maximum value;

the time at which the mechanical noise and the fluid noise occur is different, and the time at which the maximum value and the maximum value of the theoretical time domain sound pressure signal occur is different.

Based on the difference of contribution degree of mechanical noise and fluid noise to the theoretical time domain sound pressure signal and the moment difference generated by the mechanical noise and the fluid noise, the theoretical time domain sound pressure signal of the high-speed switch valve has four times of large sound pressure amplitude values in one period, the maximum sound pressure amplitude value is the maximum value of the theoretical time domain sound pressure signal, and the rest three sound pressure amplitude values are the maximum values of the theoretical time domain sound pressure signal, namely, the maximum value of the time domain sound pressure signal;

comparing the theoretical time domain sound pressure signal with the time domain sound pressure signal of the high-speed switch valve, if the theoretical time domain sound pressure signal is consistent with the time domain sound pressure signal of the high-speed switch valve, indicating that the high-speed switch valve has no fault, and if the theoretical time domain sound pressure signal is inconsistent with the time domain sound pressure signal of the high-speed switch valve, indicating that the high-speed switch valve has fault.

The high-speed switch valve event corresponding to the time domain acoustic pressure signal maximum generation time is: mechanical collision between movable parts and fixed parts in the high-speed switch valve at the moment of closing the valve port of the high-speed switch valve;

the time domain sound pressure maximum value is corresponding to a high-speed switch valve event because of fluid pressure impact of closing of a valve port of the high-speed switch valve; in the event, at the moment of closing the valve port, the moment when the fluid pressure impact occurs is delayed from the mechanical collision due to the existence of fluid inertia, viscosity and compressibility;

the high-speed switch valve event corresponding to the time domain sound pressure maximum value II is caused by fluid pressure impact at the moment of opening the valve port of the high-speed switch valve; in the event, when the valve port is opened, oil flows through a narrow valve port to cause fluid pressure impact, and a certain time is required from the valve port opening moment to the valve port complete opening, so that the moment of mechanical collision when the valve port is opened lags behind the fluid pressure impact;

the high-speed switching valve event corresponding to the time domain sound pressure maximum value III is caused by the fact that the valve port of the high-speed switching valve is completely opened, and mechanical collision between a movable part and a fixed part in the high-speed switching valve is caused when the valve port is at the maximum opening.

The high-speed switching valve fault types comprise that a valve port cannot be opened, a valve port cannot be closed, and the frequency of opening and closing of a valve core is inconsistent with the frequency of the driven PWM wave;

the failure judgment feature that the valve port cannot be opened is that the time domain sound pressure signal is flat and has no maximum value;

the failure judgment feature that the valve port cannot be closed is that the time domain sound pressure signal has only one maximum value;

the failure judgment feature that the opening and closing frequency of the valve core is inconsistent with the frequency of the driven PWM wave 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.

The high-speed switch valve is a normally open high-speed switch valve.

The normally open high-speed switch valve comprises a shell (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 cavity (9), an oil inlet P and a working port A;

when the high-speed switching valve works, the electromagnetic coil generates electromagnetic force under the drive of PWM waves to push the armature to move, the armature pushes the push rod to move, the push rod pushes the valve core to move, and when the valve core impacts the valve seat, the valve port is closed; under the action of fluid force and spring force, the valve port is opened, and when the armature impacts the gasket, the valve port is completely opened;

the return spring enables the armature, the push rod and the valve core to be in a contact state all the time;

the mechanical noise generating part of the high-speed switching valve comprises an armature and a gasket, an armature and a push rod, a push rod and a valve core, and a contact part of the valve core and a valve seat; when the valve port is closed, the collision happens at an instant, so that the contact part of the armature and the push rod collides a1, the contact part of the push rod and the valve core collides a2, the contact part of the valve core and the valve seat collides a3, the three collisions simultaneously happen and generate mechanical noise, and meanwhile, when the valve port is closed, the oil inlet cavity changes drastically, the fluid pressure in the valve cavity impacts a4, and the fluid noise I is generated; the valve core collides with the contact part b3 of the push rod, the contact part b2 of the push rod and the armature, the contact part b1 of the armature and the gasket, the three collisions occur simultaneously and generate mechanical noise, and simultaneously, when the valve port is opened, high-pressure oil flows through a narrow gap of the valve port to generate fluid pressure impact b4 to generate fluid noise II.

According to the invention, according to the difference of the contribution quantity of mechanical noise and fluid noise to the sound pressure of the high-speed switch valve and the difference of the occurrence time of the mechanical noise and the fluid noise, the time domain sound pressure signals of the mechanical noise and the fluid noise of the high-speed switch valve in an actual hydraulic system are detected by adopting the sound pressure sensor.

The invention can carry out fault identification according to the time domain sound pressure characteristics of mechanical noise and fluid noise generated by the movement of internal parts when the high-speed switch valve works in the hydraulic system, can analyze the cause of the fault and improves the fault identification efficiency.

Drawings

The invention is described in further detail below with reference to the attached drawings and detailed description:

FIG. 1 is a diagram of a high speed switch valve fault identification technique in accordance with a preferred embodiment of the present invention;

FIG. 2 is a schematic diagram of a sound pressure sensor placement mode (A1 is a sound pressure sensor, A2 is a switch valve) according to a preferred embodiment of the invention;

FIG. 3 is a schematic view of the high-speed switching valve according to the preferred embodiment of the present invention;

FIG. 4 is a schematic diagram of the mechanical noise and fluid noise generating portion of the valve port of the preferred embodiment of the present invention when closed;

FIG. 5 is a schematic diagram of the mechanical noise and fluid noise generating portion of the preferred embodiment of the present invention when the valve port is open;

FIG. 6 is a schematic diagram of mechanical noise and fluid noise time domain acoustic pressure in accordance with a preferred embodiment of the present invention;

in the figure: the device comprises a shell (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 cavity (9), an oil inlet P and a working port A.

Detailed Description

As shown in the figure, the high-speed switching valve fault identification method based on the characteristics of fluid noise and mechanical noise is characterized in that: the method comprises the steps of collecting time domain sound pressure signals of fluid noise and mechanical noise and judging fault types, wherein the method firstly analyzes the characteristics of the mechanical noise and the fluid noise of the high-speed switch valve according to the reasons formed by the mechanical noise and the fluid noise of the high-speed switch valve and by combining the structural characteristics of the high-speed switch valve, and then summarizes the characteristics of the time domain sound pressure signals of the high-speed switch valve based on the analyzed characteristics of the mechanical noise and the fluid noise; then the following steps are performed;

step S100: placing an acoustic pressure sensor for measuring time domain signals of fluid noise and mechanical noise on one side of the high-speed switching valve;

step S200: PWM wave driving is carried out on the high-speed switching valve, so that the high-speed switching valve works;

step S300: the sound pressure sensor collects a time domain sound pressure signal of the high-speed switching valve, and the time domain sound pressure signal contains fluid noise and mechanical noise information of the high-speed switching valve;

step S400: analyzing and extracting the time domain sound pressure signal to obtain the frequency of the time domain sound pressure signal, the maximum value and the maximum value of the time domain signal in one period, and marking the occurrence time of the maximum value and the maximum value;

step S500: comparing the frequency of the time domain sound pressure signal with the frequency of the PWM wave, evaluating the time when the maximum value and the maximum value of the time domain sound pressure signal appear, and further judging whether the high-speed switch valve fails or not.

The sound pressure sensor is arranged on the side edge of the high-speed switch valve, the axial direction of the sound pressure sensor is perpendicular to the axial direction of the high-speed switch valve, and the sound pressure sensor records mechanical noise generated by collision between a movable part and a fixed part of the high-speed switch valve and records fluid noise caused by fluid pressure impact in the valve cavity.

The basis for judging the fault type comprises comparison of the time domain sound pressure signal acquired by the sound pressure sensor and the theoretical time domain sound pressure signal.

The mechanical noise is generated because: when the high-speed switch valve works, collision occurs between the movable part and the fixed part in the high-speed switch valve, so that mechanical noise is generated; comprising the following steps: at the moment of closing the valve port, the movable part and the fixed part in the high-speed switch valve immediately collide mechanically to generate first mechanical noise; when the valve port is at the maximum opening, the movable part and the fixed part in the high-speed switch valve collide to generate mechanical noise II;

the fluid noise is generated as follows: the valve port of the high-speed switch valve triggers fluid pressure impact at the moment of opening and closing, thereby generating fluid noise; comprising the following steps: the high-speed switch valve transmits fluid with inertia, viscosity and compressibility, fluid pressure impact is not maximum at the moment of closing the valve port, and fluid noise I is generated when the fluid pressure impact reaches the maximum; when the valve port of the high-speed switch valve is closed, the first occurrence time of the fluid noise lags behind the first mechanical noise; at the moment of opening the valve port, high-pressure fluid immediately flows through a narrow valve port, so that fluid pressure impact is caused, and second fluid noise is generated; the valve port of the high-speed switching valve needs a certain time period from the moment of opening to the moment of the maximum opening of the valve port, and when the valve port is opened, the moment of occurrence of mechanical noise II lags behind fluid noise II;

according to different occurrence moments of mechanical noise and fluid noise, and different contributions of the mechanical noise and the fluid noise to sound pressure levels, a maximum value point appears on a sound pressure level curve of the high-speed switch valve, wherein the three maximum value points correspond to mechanical noise I generated at the moment of closing a valve port, the maximum value point I corresponds to fluid noise I at the moment of closing the valve port, the maximum value point II corresponds to fluid noise II at the moment of opening the valve port, and the maximum value point III corresponds to mechanical noise II at the moment of completely opening the valve port;

in the high-speed switch valve, factors affecting the theoretical time-domain acoustic pressure signal include mechanical noise characteristics and fluid noise characteristics;

the theoretical time domain sound pressure signal comprises the time at which mechanical noise and fluid noise appear, and the contribution degree of the mechanical noise and the fluid noise to the total noise;

the contribution degree of the mechanical noise and the fluid noise to the total noise is different, and the theoretical time domain sound pressure signal has a maximum value and a maximum value;

the time at which the mechanical noise and the fluid noise occur is different, and the time at which the maximum value and the maximum value of the theoretical time domain sound pressure signal occur is different.

Based on the difference of contribution degree of mechanical noise and fluid noise to the theoretical time domain sound pressure signal and the moment difference generated by the mechanical noise and the fluid noise, the theoretical time domain sound pressure signal of the high-speed switch valve has four times of large sound pressure amplitude values in one period, the maximum sound pressure amplitude value is the maximum value of the theoretical time domain sound pressure signal, and the rest three sound pressure amplitude values are the maximum values of the theoretical time domain sound pressure signal, namely, the maximum value of the time domain sound pressure signal;

comparing the theoretical time domain sound pressure signal with the time domain sound pressure signal of the high-speed switch valve, if the theoretical time domain sound pressure signal is consistent with the time domain sound pressure signal of the high-speed switch valve, indicating that the high-speed switch valve has no fault, and if the theoretical time domain sound pressure signal is inconsistent with the time domain sound pressure signal of the high-speed switch valve, indicating that the high-speed switch valve has fault.

The high-speed switch valve event corresponding to the time domain acoustic pressure signal maximum generation time is: mechanical collision between movable parts and fixed parts in the high-speed switch valve at the moment of closing the valve port of the high-speed switch valve;

the time domain sound pressure maximum value is corresponding to a high-speed switch valve event because of fluid pressure impact of closing of a valve port of the high-speed switch valve; in the event, at the moment of closing the valve port, the moment when the fluid pressure impact occurs is delayed from the mechanical collision due to the existence of fluid inertia, viscosity and compressibility;

the high-speed switch valve event corresponding to the time domain sound pressure maximum value II is caused by fluid pressure impact at the moment of opening the valve port of the high-speed switch valve; in the event, when the valve port is opened, oil flows through a narrow valve port to cause fluid pressure impact, and a certain time is required from the valve port opening moment to the valve port complete opening, so that the moment of mechanical collision when the valve port is opened lags behind the fluid pressure impact;

the high-speed switching valve event corresponding to the time domain sound pressure maximum value III is caused by the fact that the valve port of the high-speed switching valve is completely opened, and mechanical collision between a movable part and a fixed part in the high-speed switching valve is caused when the valve port is at the maximum opening.

The high-speed switching valve fault types comprise that a valve port cannot be opened, a valve port cannot be closed, and the frequency of opening and closing of a valve core is inconsistent with the frequency of the driven PWM wave;

the failure judgment feature that the valve port cannot be opened is that the time domain sound pressure signal is flat and has no maximum value;

the failure judgment feature that the valve port cannot be closed is that the time domain sound pressure signal has only one maximum value;

the failure judgment feature that the opening and closing frequency of the valve core is inconsistent with the frequency of the driven PWM wave 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.

The high-speed switch valve is a normally open high-speed switch valve.

The normally open high-speed switch valve comprises a shell 1, a gasket 2, an electromagnetic coil 3, an armature 4, a push rod 5, a valve core 6, a valve seat 7, a reset spring 8, an oil inlet cavity 9, an oil inlet P and a working port A;

when the high-speed switching valve works, the electromagnetic coil generates electromagnetic force under the drive of PWM waves to push the armature to move, the armature pushes the push rod to move, the push rod pushes the valve core to move, and when the valve core impacts the valve seat, the valve port is closed; under the action of fluid force and spring force, the valve port is opened, and when the armature impacts the gasket, the valve port is completely opened;

the return spring enables the armature, the push rod and the valve core to be in a contact state all the time;

the mechanical noise generating part of the high-speed switching valve comprises an armature and a gasket, an armature and a push rod, a push rod and a valve core, and a contact part of the valve core and a valve seat; when the valve port is closed, the collision happens at an instant, so that the contact part of the armature and the push rod collides a1, the contact part of the push rod and the valve core collides a2, the contact part of the valve core and the valve seat collides a3, the three collisions simultaneously happen and generate mechanical noise, and meanwhile, when the valve port is closed, the oil inlet cavity changes drastically, the fluid pressure in the valve cavity impacts a4, and the fluid noise I is generated; the valve core collides with the contact part b3 of the push rod, the contact part b2 of the push rod and the armature, the contact part b1 of the armature and the gasket, the three collisions occur simultaneously and generate mechanical noise, and simultaneously, when the valve port is opened, high-pressure oil flows through a narrow gap of the valve port to generate fluid pressure impact b4 to generate fluid noise II.

Examples:

in this example, the technical scheme is shown in fig. 1.

Based on the fault identification method, the implemented fault detection steps include:

PWM wave voltage excitation is carried out on the high-speed switching valve, so that the high-speed switching valve works;

placing an acoustic pressure sensor for measuring fluid noise and mechanical noise on one side of the high-speed switching valve; as shown in fig. 2, the sound pressure sensor A1 is disposed at the side of the high-speed switch valve A2, and the axial direction of the sound pressure sensor is perpendicular to the axial direction of the high-speed switch valve, and records the mechanical noise of the high-speed switch valve caused by the collision of the movable part and the fixed part, and simultaneously records the fluid noise caused by the impact of the fluid pressure in the valve cavity;

the sound pressure sensor collects a time domain sound pressure signal of the high-speed switching valve, and the time domain sound pressure signal of the high-speed switching valve comprises fluid noise and mechanical noise information of the high-speed switching valve;

analyzing and extracting the time domain sound pressure signal to obtain the frequency of the time domain sound pressure signal, the maximum value and the maximum value of the signal in one period, and marking the occurrence time of the maximum value and the maximum value;

comparing the obtained frequency of the time domain sound pressure signal with the frequency of the driving PWM wave, wherein 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, and the fault type is that the opening and closing frequency of the valve core is inconsistent with the frequency of the driving PWM wave

If the obtained sound pressure signal has no periodicity, the time domain sound pressure signal is flat and has no maximum value, and the fault type is that the valve port cannot be opened;

if the obtained sound pressure signal is not periodic but has a maximum value, the fault type valve port cannot be closed.

The structure diagram of the high-speed switch valve is shown in fig. 3, and the normally open high-speed switch valve comprises a shell 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 cavity 9, an oil inlet P and a working port A;

when the high-speed switching valve works, the electromagnetic coil generates electromagnetic force under the drive of PWM waves to push the armature to move, the armature pushes the push rod to move, the push rod pushes the valve core to move, and when the valve core impacts the valve seat, the valve port is closed; under the action of fluid force and spring force, the valve port is opened, and when the armature impacts the gasket, the valve port is completely opened;

the return spring enables the armature, the push rod and the valve core to be in contact all the time, and mechanical noise mainly generates contact parts between the armature and the gasket, between the armature and the push rod, between the push rod and the valve core, between the valve core and the valve seat; as shown in fig. 4, when the valve port is closed, since the collision occurs at a moment, the contact part of the armature and the push rod collides a1, the contact part of the push rod and the valve core collides a2, the contact part of the valve core and the valve seat collides a3, the three collisions occur simultaneously and generate mechanical noise, and meanwhile, when the valve port is closed, the cavity of the oil inlet cavity changes drastically, the fluid pressure in the valve cavity impacts a4, and the first fluid noise is generated; as shown in fig. 5, when the valve port is completely opened, the collision occurs at a moment, the valve core collides with the contact part of the push rod b3, the push rod collides with the contact part of the armature b2, the armature collides with the contact part of the gasket b1, the three collisions occur simultaneously and generate mechanical noise, and simultaneously when the valve port is opened, high-pressure oil flows through a narrow gap of the valve port to generate fluid pressure impact b4 to generate second fluid noise;

as shown in fig. 6, the sound pressure signal includes a first mechanical noise a, a first fluid noise B, a second fluid noise C, and a second mechanical noise D, which are specifically expressed as: the sound pressure signal can appear a maximum point, and three maximum points, and the moment that the maximum point appears corresponds first mechanical noise A, and the moment that the first maximum point appears corresponds first fluid noise B, and the moment that the second maximum point appears corresponds second fluid noise C, and the moment that the third maximum point appears corresponds second mechanical noise D.

In this example, the theoretical time domain sound pressure signal data for fault judgment is obtained according to the hardware design characteristics of the high-speed switch valve, or provided by a manufacturer, or a high-speed on-off test is performed by using a newly purchased high-speed switch valve to collect related data.

Claims (9)

1. The high-speed switch valve fault identification method based on the characteristics of fluid noise and mechanical noise is characterized by comprising the following steps of: the method comprises the steps of collecting time domain sound pressure signals of fluid noise and mechanical noise and judging fault types, wherein the method firstly analyzes the characteristics of the mechanical noise and the fluid noise of the high-speed switch valve according to the reasons formed by the mechanical noise and the fluid noise of the high-speed switch valve and by combining the structural characteristics of the high-speed switch valve, and then summarizes the characteristics of the time domain sound pressure signals of the high-speed switch valve based on the analyzed characteristics of the mechanical noise and the fluid noise; then the following steps are performed;

step S100: placing an acoustic pressure sensor for measuring time domain signals of fluid noise and mechanical noise on one side of the high-speed switching valve;

step S200: PWM wave driving is carried out on the high-speed switching valve, so that the high-speed switching valve works;

step S300: the sound pressure sensor collects a time domain sound pressure signal of the high-speed switching valve, and the time domain sound pressure signal contains fluid noise and mechanical noise information of the high-speed switching valve;

step S400: analyzing and extracting the time domain sound pressure signal to obtain the frequency of the time domain sound pressure signal, the maximum value and the maximum value of the time domain signal in one period, and marking the occurrence time of the maximum value and the maximum value;

step S500: comparing the frequency of the time domain sound pressure signal with the frequency of the PWM wave, evaluating the time when the maximum value and the maximum value of the time domain sound pressure signal appear, and further judging whether the high-speed switch valve fails or not.

2. The method for identifying faults of a high-speed switching valve based on characteristics of fluid noise and mechanical noise according to claim 1, characterized in that: the sound pressure sensor is arranged on the side edge of the high-speed switch valve, the axial direction of the sound pressure sensor is perpendicular to the axial direction of the high-speed switch valve, and the sound pressure sensor records mechanical noise generated by collision between a movable part and a fixed part of the high-speed switch valve and records fluid noise caused by fluid pressure impact in the valve cavity.

3. The method for identifying faults of a high-speed switching valve based on characteristics of fluid noise and mechanical noise according to claim 1, characterized in that: the basis for judging the fault type comprises comparison of the time domain sound pressure signal acquired by the sound pressure sensor and the theoretical time domain sound pressure signal.

4. A method for identifying a high-speed switching valve fault based on fluid noise and mechanical noise characteristics according to claim 3, wherein: the mechanical noise is generated because: when the high-speed switch valve works, collision occurs between the movable part and the fixed part in the high-speed switch valve, so that mechanical noise is generated; comprising the following steps: at the moment of closing the valve port, the movable part and the fixed part in the high-speed switch valve immediately collide mechanically to generate first mechanical noise; when the valve port is at the maximum opening, the movable part and the fixed part in the high-speed switch valve collide to generate mechanical noise II;

the fluid noise is generated as follows: the valve port of the high-speed switch valve triggers fluid pressure impact at the moment of opening and closing, thereby generating fluid noise; comprising the following steps: the high-speed switch valve transmits fluid with inertia, viscosity and compressibility, fluid pressure impact is not maximum at the moment of closing the valve port, and fluid noise I is generated when the fluid pressure impact reaches the maximum; when the valve port of the high-speed switch valve is closed, the first occurrence time of the fluid noise lags behind the first mechanical noise; at the moment of opening the valve port, high-pressure fluid immediately flows through a narrow valve port, so that fluid pressure impact is caused, and second fluid noise is generated; the valve port of the high-speed switching valve needs a certain time period from the moment of opening to the moment of the maximum opening of the valve port, and when the valve port is opened, the moment of occurrence of mechanical noise II lags behind fluid noise II;

according to different occurrence moments of mechanical noise and fluid noise, and different contributions of the mechanical noise and the fluid noise to sound pressure levels, a maximum value point appears on a sound pressure level curve of the high-speed switch valve, wherein the three maximum value points correspond to mechanical noise I generated at the moment of closing a valve port, the maximum value point I corresponds to fluid noise I at the moment of closing the valve port, the maximum value point II corresponds to fluid noise II at the moment of opening the valve port, and the maximum value point III corresponds to mechanical noise II at the moment of completely opening the valve port;

in the high-speed switch valve, factors affecting the theoretical time-domain acoustic pressure signal include mechanical noise characteristics and fluid noise characteristics;

the theoretical time domain sound pressure signal comprises the time at which mechanical noise and fluid noise appear, and the contribution degree of the mechanical noise and the fluid noise to the total noise;

the contribution degree of the mechanical noise and the fluid noise to the total noise is different, and the theoretical time domain sound pressure signal has a maximum value and a maximum value;

the time at which the mechanical noise and the fluid noise occur is different, and the time at which the maximum value and the maximum value of the theoretical time domain sound pressure signal occur is different.

5. The method for identifying faults of a high-speed switching valve based on characteristics of fluid noise and mechanical noise according to claim 4, wherein the method comprises the following steps: based on the difference of contribution degree of mechanical noise and fluid noise to the theoretical time domain sound pressure signal and the moment difference generated by the mechanical noise and the fluid noise, the theoretical time domain sound pressure signal of the high-speed switch valve has four times of large sound pressure amplitude values in one period, the maximum sound pressure amplitude value is the maximum value of the theoretical time domain sound pressure signal, and the rest three sound pressure amplitude values are the maximum values of the theoretical time domain sound pressure signal, namely, the maximum value of the time domain sound pressure signal;

comparing the theoretical time domain sound pressure signal with the time domain sound pressure signal of the high-speed switch valve, if the theoretical time domain sound pressure signal is consistent with the time domain sound pressure signal of the high-speed switch valve, indicating that the high-speed switch valve has no fault, and if the theoretical time domain sound pressure signal is inconsistent with the time domain sound pressure signal of the high-speed switch valve, indicating that the high-speed switch valve has fault.

6. A method for identifying a high-speed switching valve fault based on fluid noise and mechanical noise characteristics according to claim 3, wherein: the high-speed switch valve event corresponding to the time domain acoustic pressure signal maximum generation time is: mechanical collision between movable parts and fixed parts in the high-speed switch valve at the moment of closing the valve port of the high-speed switch valve;

the time domain sound pressure maximum value is corresponding to a high-speed switch valve event because of fluid pressure impact of closing of a valve port of the high-speed switch valve; in the event, at the moment of closing the valve port, the moment when the fluid pressure impact occurs is delayed from the mechanical collision due to the existence of fluid inertia, viscosity and compressibility;

the high-speed switch valve event corresponding to the time domain sound pressure maximum value II is caused by fluid pressure impact at the moment of opening the valve port of the high-speed switch valve; in the event, when the valve port is opened, oil flows through a narrow valve port to cause fluid pressure impact, and a certain time is required from the valve port opening moment to the valve port complete opening, so that the moment of mechanical collision when the valve port is opened lags behind the fluid pressure impact;

the high-speed switching valve event corresponding to the time domain sound pressure maximum value III is caused by the fact that the valve port of the high-speed switching valve is completely opened, and mechanical collision between a movable part and a fixed part in the high-speed switching valve is caused when the valve port is at the maximum opening.

7. The method for identifying faults of a high-speed switching valve based on characteristics of fluid noise and mechanical noise according to claim 5, characterized in that: the high-speed switching valve fault types comprise that a valve port cannot be opened, a valve port cannot be closed, and the frequency of opening and closing of a valve core is inconsistent with the frequency of the driven PWM wave;

the failure judgment feature that the valve port cannot be opened is that the time domain sound pressure signal is flat and has no maximum value;

the failure judgment feature that the valve port cannot be closed is that the time domain sound pressure signal has only one maximum value;

the failure judgment feature that the opening and closing frequency of the valve core is inconsistent with the frequency of the driven PWM wave 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.

8. The method for identifying faults of a high-speed switching valve based on characteristics of fluid noise and mechanical noise according to claim 7, wherein the method comprises the following steps: the high-speed switch valve is a normally open high-speed switch valve.

9. The method for identifying faults of a high-speed switching valve based on characteristics of fluid noise and mechanical noise according to claim 8, wherein the method comprises the following steps: the normally open high-speed switch valve comprises a shell (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 cavity (9), an oil inlet P and a working port A;

when the high-speed switching valve works, the electromagnetic coil generates electromagnetic force under the drive of PWM waves to push the armature to move, the armature pushes the push rod to move, the push rod pushes the valve core to move, and when the valve core impacts the valve seat, the valve port is closed; under the action of fluid force and spring force, the valve port is opened, and when the armature impacts the gasket, the valve port is completely opened;

the return spring enables the armature, the push rod and the valve core to be in a contact state all the time;

the mechanical noise generating part of the high-speed switching valve comprises an armature and a gasket, an armature and a push rod, a push rod and a valve core, and a contact part of the valve core and a valve seat; when the valve port is closed, the collision happens at an instant, so that the contact part of the armature and the push rod collides a1, the contact part of the push rod and the valve core collides a2, the contact part of the valve core and the valve seat collides a3, the three collisions simultaneously happen and generate mechanical noise, and meanwhile, when the valve port is closed, the oil inlet cavity changes drastically, the fluid pressure in the valve cavity impacts a4, and the fluid noise I is generated; the valve core collides with the contact part b3 of the push rod, the contact part b2 of the push rod and the armature, the contact part b1 of the armature and the gasket, the three collisions occur simultaneously and generate mechanical noise, and simultaneously, when the valve port is opened, high-pressure oil flows through a narrow gap of the valve port to generate fluid pressure impact b4 to generate fluid noise II.