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

Abstract

The present invention proposes a high-speed switching valve fault identification method based on fluid noise and mechanical noise characteristics, which can realize fault identification when the high-speed switching valve is working in a hydraulic system. The sound pressure sensor on the side measures the time-domain sound pressure signal of the high-speed switching valve, which includes the characteristics of mechanical noise and fluid noise. By comparing the theoretical time-domain sound pressure signal with the time-domain sound pressure signal of the high-speed switching valve to be tested, the maximum point, the moment when the maximum point appears, and the size of the maximum point and the maximum point can be used to judge the interior of the high-speed switching valve. Whether there is a fault; the present invention can perform fault identification according to the time-domain sound pressure characteristics of the mechanical noise and fluid noise generated by the movement of internal components when the high-speed switching valve is working in the hydraulic system, and can analyze the cause of the fault to improve the efficiency of fault identification.

Description

Fault identification method for high-speed switching valve based on fluid noise and mechanical noise characteristics

technical field

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

Background technique

Due to its small size, low cost, and flexible control, high-speed switching valves are widely used in many fields. The high-speed switching valve has only two states of fully open and fully closed when it is working without failure. Driven by high-frequency PWM signal, the spool of the high-speed switching valve opens and closes quickly, so as to realize the flow control. In actual use, the high-speed switching valve is usually connected with the valve block and arranged in the hydraulic system. In the hydraulic system, due to the existence of oil, the movement state of the spool will change, and there will be stuck or stuck phenomenon, so that the high-speed switching valve cannot be opened and closed normally or cannot keep up with the frequency of the driving model. The existing technology has not realized the fault diagnosis of the high-speed switching valve in the hydraulic system, because the volume of the high-speed switching valve is small, the valve core is surrounded by oil, it is difficult to directly install the displacement sensor and other methods to monitor the displacement of the high-speed switching valve. measurement, so as to determine whether there is a fault.

Mechanical noise and fluid noise will inevitably be generated during the rapid opening and closing of the high-speed switching valve spool. The mechanical noise mainly comes from the mechanical collision between the movable parts and the fixed parts inside the high-speed switching valve, and the fluid noise mainly comes from the movement of the spool. The fluid pressure shock caused by the volume change of the valve cavity. Driven by periodic PWM waves, the spool of the high-speed on-off valve will open and close periodically and rapidly, resulting in periodically changing mechanical noise and fluid noise. And because the sources of mechanical noise and fluid noise are different, and fluid has viscosity, inertia, and compressibility, this leads to different moments when mechanical noise and fluid noise are generated, and the characteristics of the generated mechanical noise and fluid noise are also different.

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

Contents of the invention

The present invention proposes a fault identification method for high-speed switching valves based on the characteristics of fluid noise and mechanical noise. According to the difference in the contribution of mechanical noise and fluid noise to the sound pressure of high-speed switching valves, and the time at which mechanical noise and fluid noise appear, a sound pressure sensor is used. Detect the time-domain sound pressure signals of the mechanical noise and fluid noise of the high-speed switching valve in the actual hydraulic system, and identify different types of faults according to the above characteristics.

The present invention adopts the following technical solutions.

A fault identification method for high-speed switching valves based on fluid noise and mechanical noise features, characterized in that: the method includes time-domain sound pressure signal collection of fluid noise and mechanical noise, and also includes fault type judgment. The reasons for the formation of mechanical noise and fluid noise, combined with the structural characteristics of high-speed switching valves, analyze the characteristics of mechanical noise and fluid noise of high-speed switching valves, and then based on the analyzed characteristics of mechanical noise and fluid noise, summarize the time-domain sound pressure signals of high-speed switching valves characteristics; then perform the following steps;

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: performing PWM wave driving on the high-speed on-off valve to make the high-speed on-off valve work;

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 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 value and maximum value of the time-domain signal within one cycle, and mark the maximum value and the moment when the maximum value appears;

Step S500: Compare the frequency of the time-domain sound pressure signal with the frequency of the PWM wave, evaluate the maximum value of the time-domain sound pressure signal and the time when the maximum value appears, and then determine whether the high-speed switching valve is faulty.

The sound pressure sensor is placed on the side of the high-speed switching valve, and the axis direction of the sound pressure sensor is perpendicular to the axis direction of the high-speed switching valve. The sound pressure sensor records the mechanical noise generated by the collision between the movable part and the fixed part of the high-speed switching valve , while recording the fluid noise caused by the fluid pressure shock inside the valve cavity.

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

The reason for the generation of the mechanical noise is: when the high-speed switching valve is working, there is a collision between the internal movable part and the fixed part, thereby generating mechanical noise; including: when the valve port is closed, the internal movable parts and the Immediate mechanical collision of the fixed parts produces mechanical noise 1; when the valve port is at the maximum opening, the movable parts and fixed parts inside the high-speed switching valve collide, producing mechanical noise 2;

The reason for the generation of the fluid noise is: the high-speed switching valve valve port causes a fluid pressure shock at the moment of opening and closing, thereby generating fluid noise; including: the high-speed switching valve transmits inertial, viscous, and compressible fluids. At the moment of closing, the fluid pressure impact does not reach the maximum. When the fluid pressure impact reaches the maximum, fluid noise is generated; when the valve port of the high-speed switching valve is closed, the time of fluid noise lags behind the mechanical noise; when the valve port is opened In an instant, the high-pressure fluid flows through the narrow valve port immediately, causing fluid pressure shock and fluid noise; , the occurrence time of mechanical noise 2 lags behind that of fluid noise 2;

According to the different occurrence times of mechanical noise and fluid noise, and the different contributions of mechanical noise and fluid noise to the sound pressure level, a maximum point, three maximum points, and a maximum value appear on the sound pressure level curve of the high-speed switching valve. Point 1 corresponds to the mechanical noise generated at the moment the valve port is closed, maximum value point 1 corresponds to the fluid noise 1 when the valve port is closed, and maximum value point 2 corresponds to the fluid noise 2 at the moment the valve port is opened. Value point three corresponds to mechanical noise two when the valve port is fully opened;

In the high-speed switching valve, 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 moment when mechanical noise and fluid noise appear, and the contribution of mechanical noise and fluid noise to the total noise;

There are differences in the contribution of the mechanical noise and the fluid noise to the total noise, and cause the maximum and maximum values of the theoretical time-domain sound pressure signal;

There are differences in the occurrence times of the mechanical noise and the fluid noise, which make the maximum value and the maximum value of the theoretical time-domain sound pressure signal different.

Based on the difference in the contribution of mechanical noise and fluid noise to the theoretical time-domain sound pressure signal, and the time difference between mechanical noise and fluid noise, the theoretical time-domain sound pressure signal of a high-speed switching valve has four large sound pressures in one cycle Amplitude, the largest sound pressure amplitude is the maximum value of the theoretical time-domain sound pressure signal, and the remaining three sound pressure amplitudes are the maximum value of the theoretical time-domain sound pressure signal, which are respectively the maximum value of the time-domain sound pressure signal One, the maximum value of the time-domain sound pressure signal two, the maximum value of the time-domain sound pressure signal three;

Compare the theoretical time-domain sound pressure signal 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 means that the high-speed switching valve is not faulty. If not, It shows that the high-speed switching valve is faulty.

The high-speed switching valve event corresponding to the generation time of the maximum value of the time-domain sound pressure signal is: the moment the valve port of the high-speed switching valve is closed, the mechanical collision between the movable part and the fixed part inside the high-speed switching valve;

The high-speed switching valve event corresponding to the time-domain sound pressure maximum value is due to the fluid pressure impact of the high-speed switching valve valve port closing; , the moment when the fluid pressure shock occurs when the valve port is closed lags behind the mechanical collision;

The high-speed on-off valve event corresponding to the time-domain sound pressure maximum value two is due to the fluid pressure impact at the moment when the valve port of the high-speed switch valve is opened; Cause fluid pressure impact, and it takes a certain amount of time from the moment the valve port is opened to the valve port is fully opened, causing the mechanical collision when the valve port is opened to lag behind the fluid pressure impact;

The high-speed switching valve event corresponding to the time-domain sound pressure maximum value three is because the valve port of the high-speed switching valve is fully opened, and the mechanical collision between the movable part and the fixed part inside the high-speed switching valve is at the maximum opening.

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

The fault judgment feature of the failure of the valve port to open is that the sound pressure signal in the time domain is flat and has no maximum value;

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

The fault judgment feature that the frequency of the spool opening and closing is inconsistent with the frequency of the driven PWM wave is that the time-domain sound pressure signal has a maximum value and three maximum values, but the frequency of the time-domain sound pressure signal and the frequency of the PWM wave Inconsistent.

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

The normally open high-speed switching valve includes a casing (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), oil inlet port (9), oil inlet P, working port A;

When the high-speed switching valve is in operation, the electromagnetic coil is driven by PWM waves to generate electromagnetic force to push the armature to move, the armature to push the push rod to move, the push rod to push the valve core to move, and when the valve core hits 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 hits the gasket, the valve port is fully opened;

The return spring keeps the armature, the push rod and the spool in contact all the time;

The mechanical noise generating parts of the high-speed switching valve include the contact parts 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; 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, and the collisions of the three places occur at the same time and generate mechanical noise. At the same time, when the valve port is closed, The cavity of the oil inlet cavity changes drastically, and the fluid pressure impacts a4 in the valve cavity, resulting in fluid noise; a collision occurs at the moment when the valve port is fully opened, specifically, the contact part of the valve core and the push rod collides b3, and the push rod Collision b2 occurs at the contact part with the armature, and b1 occurs at the contact part between the armature and the gasket. The three collisions occur simultaneously and generate mechanical noise. At the same time, when the valve port is opened, high-pressure oil flows through the narrow gap of the valve port to generate fluid pressure. Impact b4, producing fluid noise two.

According to the difference in the contribution of mechanical noise and fluid noise to the sound pressure of the high-speed switching valve, and the time at which the mechanical noise and fluid noise appear, the sound pressure sensor is used to detect the mechanical noise and fluid noise of the high-speed switching valve in the actual hydraulic system. The time-domain sound pressure signal, the present invention can perform fault identification on different types of faults based on the characteristics of the above-mentioned signals, which is helpful to realize the fault diagnosis of high-speed switching valves in the hydraulic system.

The invention can perform 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 switching valve works in a hydraulic system, and can analyze the cause of the fault to improve the efficiency of fault identification.

Description of drawings

Below in conjunction with accompanying drawing and specific embodiment the present invention is described in further detail:

Accompanying drawing 1 is the high-speed switching valve fault identification technical scheme of the preferred embodiment of the present invention;

Accompanying drawing 2 is the schematic diagram of placement mode of the sound pressure sensor of the preferred embodiment of the present invention (A1 is the sound pressure sensor, A2 is the switch valve);

Accompanying drawing 3 is the schematic structural diagram of the high-speed switching valve of the preferred embodiment of the present invention;

Accompanying drawing 4 is the schematic diagram of the location where mechanical noise and fluid noise are generated when the valve port is closed in a preferred embodiment of the present invention;

Accompanying drawing 5 preferred embodiment of the present invention is the mechanical noise and the schematic diagram of fluid noise generating position when the valve port is opened;

Accompanying drawing 6 is the time-domain sound pressure schematic diagram of mechanical noise and fluid noise of the preferred embodiment of the present invention;

In the figure: shell (1), gasket (2), electromagnetic coil (3), armature (4), push rod (5), valve core (6), valve seat (7), return spring (8), inlet Oil mouth (9), oil inlet P, working port A.

Detailed ways

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 includes time-domain sound pressure signal collection of fluid noise and mechanical noise, and also includes fault type judgment. The method First, according to the causes of the mechanical noise and fluid noise of the high-speed switching valve, combined with the structural characteristics of the high-speed switching valve, the characteristics of the mechanical noise and fluid noise of the high-speed switching valve are analyzed, and then based on the characteristics of the analyzed mechanical noise and fluid noise, the high-speed switching valve is summarized. Characteristics of the time-domain sound pressure signal; the following steps are then 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: performing PWM wave driving on the high-speed on-off valve to make the high-speed on-off valve work;

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 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 value and maximum value of the time-domain signal within one cycle, and mark the maximum value and the moment when the maximum value appears;

Step S500: Compare the frequency of the time-domain sound pressure signal with the frequency of the PWM wave, evaluate the maximum value of the time-domain sound pressure signal and the time when the maximum value appears, and then determine whether the high-speed switching valve is faulty.

The sound pressure sensor is placed on the side of the high-speed switching valve, and the axis direction of the sound pressure sensor is perpendicular to the axis direction of the high-speed switching valve. The sound pressure sensor records the mechanical noise generated by the collision between the movable part and the fixed part of the high-speed switching valve , while recording the fluid noise caused by the fluid pressure shock inside the valve cavity.

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

The reason for the generation of the mechanical noise is: when the high-speed switching valve is working, there is a collision between the internal movable part and the fixed part, thereby generating mechanical noise; including: when the valve port is closed, the internal movable parts and the Immediate mechanical collision of the fixed parts produces mechanical noise 1; when the valve port is at the maximum opening, the movable parts and fixed parts inside the high-speed switching valve collide, producing mechanical noise 2;

The reason for the generation of the fluid noise is: the high-speed switching valve valve port causes a fluid pressure shock at the moment of opening and closing, thereby generating fluid noise; including: the high-speed switching valve transmits inertial, viscous, and compressible fluids. At the moment of closing, the fluid pressure impact does not reach the maximum. When the fluid pressure impact reaches the maximum, fluid noise is generated; when the valve port of the high-speed switching valve is closed, the time of fluid noise lags behind the mechanical noise; when the valve port is opened In an instant, the high-pressure fluid flows through the narrow valve port immediately, causing fluid pressure shock and fluid noise; , the occurrence time of mechanical noise 2 lags behind that of fluid noise 2;

According to the different occurrence times of mechanical noise and fluid noise, and the different contributions of mechanical noise and fluid noise to the sound pressure level, a maximum point, three maximum points, and a maximum value appear on the sound pressure level curve of the high-speed switching valve. Point 1 corresponds to the mechanical noise generated at the moment the valve port is closed, maximum value point 1 corresponds to the fluid noise 1 when the valve port is closed, and maximum value point 2 corresponds to the fluid noise 2 at the moment the valve port is opened. Value point three corresponds to mechanical noise two when the valve port is fully opened;

In the high-speed switching valve, 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 moment when mechanical noise and fluid noise appear, and the contribution of mechanical noise and fluid noise to the total noise;

There are differences in the contribution of the mechanical noise and the fluid noise to the total noise, and cause the maximum and maximum values of the theoretical time-domain sound pressure signal;

There are differences in the occurrence times of the mechanical noise and the fluid noise, which make the maximum value and the maximum value of the theoretical time-domain sound pressure signal different.

Based on the difference in the contribution of mechanical noise and fluid noise to the theoretical time-domain sound pressure signal, and the time difference between mechanical noise and fluid noise, the theoretical time-domain sound pressure signal of a high-speed switching valve has four large sound pressures in one cycle Amplitude, the largest sound pressure amplitude is the maximum value of the theoretical time-domain sound pressure signal, and the remaining three sound pressure amplitudes are the maximum value of the theoretical time-domain sound pressure signal, which are respectively the maximum value of the time-domain sound pressure signal One, the maximum value of the time-domain sound pressure signal two, the maximum value of the time-domain sound pressure signal three;

Compare the theoretical time-domain sound pressure signal 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 means that the high-speed switching valve is not faulty. If not, It shows that the high-speed switching valve is faulty.

The high-speed switching valve event corresponding to the generation time of the maximum value of the time-domain sound pressure signal is: the moment the valve port of the high-speed switching valve is closed, the mechanical collision between the movable part and the fixed part inside the high-speed switching valve;

The high-speed switching valve event corresponding to the time-domain sound pressure maximum value is due to the fluid pressure impact of the high-speed switching valve valve port closing; , the moment when the fluid pressure shock occurs when the valve port is closed lags behind the mechanical collision;

The high-speed on-off valve event corresponding to the time-domain sound pressure maximum value two is due to the fluid pressure impact at the moment when the valve port of the high-speed switch valve is opened; Cause fluid pressure impact, and it takes a certain amount of time from the moment the valve port is opened to the valve port is fully opened, causing the mechanical collision when the valve port is opened to lag behind the fluid pressure impact;

The high-speed switching valve event corresponding to the time-domain sound pressure maximum value three is because the valve port of the high-speed switching valve is fully opened, and the mechanical collision between the movable part and the fixed part inside the high-speed switching valve is at the maximum opening.

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

The fault judgment feature of the failure of the valve port to open is that the sound pressure signal in the time domain is flat and has no maximum value;

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

The fault judgment feature that the frequency of the spool opening and closing is inconsistent with the frequency of the driven PWM wave is that the time-domain sound pressure signal has a maximum value and three maximum values, but the frequency of the time-domain sound pressure signal and the frequency of the PWM wave Inconsistent.

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

The normally open high-speed switching valve includes a casing 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, a working Port A;

When the high-speed switching valve is in operation, the electromagnetic coil is driven by PWM waves to generate electromagnetic force to push the armature to move, the armature to push the push rod to move, the push rod to push the valve core to move, and when the valve core hits 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 hits the gasket, the valve port is fully opened;

The return spring keeps the armature, the push rod and the spool in contact all the time;

The mechanical noise generating parts of the high-speed switching valve include the contact parts 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; 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, and the collisions of the three places occur at the same time and generate mechanical noise. At the same time, when the valve port is closed, The cavity of the oil inlet cavity changes drastically, and the fluid pressure impacts a4 in the valve cavity, resulting in fluid noise; a collision occurs at the moment when the valve port is fully opened, specifically, the contact part of the valve core and the push rod collides b3, and the push rod Collision b2 occurs at the contact part with the armature, and b1 occurs at the contact part between the armature and the gasket. The three collisions occur simultaneously and generate mechanical noise. At the same time, when the valve port is opened, high-pressure oil flows through the narrow gap of the valve port to generate fluid pressure. Impact b4, producing fluid noise two.

Example:

In this example, the technical solution is shown in Figure 1.

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

Excite the high-speed switching valve with PWM wave voltage to make the high-speed switching valve work;

Place the sound pressure sensor for measuring fluid noise and mechanical noise on one side of the high-speed switching valve; as shown in Figure 2, 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 Perpendicular to the axial direction of the high-speed switching valve, the sound pressure sensor records the mechanical noise of the high-speed switching valve due to the collision between the movable part and the fixed part, and records the fluid noise caused by the impact of the fluid pressure inside the valve cavity;

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

Analyzing and extracting the time-domain sound pressure signal, obtaining the frequency of the time-domain sound pressure signal, and the maximum value and maximum value of the signal within one cycle, and marking the moment when the maximum value and the maximum value appear;

Compare the frequency of the obtained time-domain sound pressure signal with the frequency of the driven PWM wave. The frequency of the time-domain sound pressure signal is inconsistent with the frequency of the driven PWM wave, but the time-domain sound pressure signal has a maximum value and three maximum values. value, the fault type is that the frequency of spool opening and closing is inconsistent with the frequency of the driving PWM wave

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

If the obtained sound pressure signal has no periodicity, but has a maximum value, then the failure type valve cannot be closed.

The structural diagram of the high-speed switching valve is shown in Figure 3. 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 reset Spring 8, oil inlet port 9, oil inlet port P, working port A;

When the high-speed switching valve is in operation, the electromagnetic coil is driven by PWM waves to generate electromagnetic force to push the armature to move, the armature to push the push rod to move, the push rod to push the valve core to move, and when the valve core hits 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 hits the gasket, the valve port is fully opened;

The return spring keeps the armature, the push rod and the valve core always in contact, and the mechanical noise mainly occurs at the contact parts 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; as shown in Figure 4 , when the valve port is closed, because the collision occurs in an instant, 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, and the three places The collision occurs at the same time and produces mechanical noise. At the same time, when the valve port is closed, the cavity of the oil inlet chamber changes drastically, and the fluid pressure impact a4 in the valve chamber generates the first fluid noise; as shown in Figure 5, when the valve port is fully opened When the collision occurs in an instant, the contact part of the valve core and the push rod collides b3, the contact part of the push rod and the armature collides b2, the contact part of the armature and the gasket collides b1, and the collision of the three places occurs simultaneously and produces mechanical noise. At the same time, when the valve port is opened, the high-pressure oil flows through the narrow gap of the valve port, resulting in fluid pressure shock b4 and second fluid noise;

As shown in Figure 6, the sound pressure signal contains the first mechanical noise A, the first fluid noise B, the second fluid noise C, and the second mechanical noise D. Specifically, the sound pressure signal will have a maximum point, and three The moment when the maximum point appears corresponds to the first mechanical noise A, the moment when the first maximum point appears corresponds to the first fluid noise B, and the moment when the second maximum point appears corresponds to is the second fluid noise C, and the moment when the third maximum point appears corresponds to the second mechanical noise D.

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

Claims (9)

1. The high-speed switching valve fault identification method based on fluid noise and mechanical noise characteristics, it is characterized in that: described method comprises the time-domain sound pressure signal collection of fluid noise and mechanical noise, also comprises fault type judgment, and described method first according to high-speed The causes of the mechanical noise and fluid noise of the switching valve, combined with the structural characteristics of the high-speed switching valve, analyze the characteristics of the mechanical noise and fluid noise of the high-speed switching valve, and then based on the characteristics of the analyzed mechanical noise and fluid noise, summarize the time-domain noise of the high-speed switching valve characteristics of the pressure signal; then perform the following steps; 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: performing PWM wave driving on the high-speed on-off valve to make the high-speed on-off valve work; 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 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 value and maximum value of the time-domain signal within one cycle, and mark the maximum value and the moment when the maximum value appears; Step S500: Compare the frequency of the time-domain sound pressure signal with the frequency of the PWM wave, evaluate the maximum value of the time-domain sound pressure signal and the time when the maximum value appears, and then determine whether the high-speed switching valve is faulty. 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 sound pressure sensor is placed on the side of the high-speed switching valve, and the axial direction of the sound pressure sensor is in line with the high-speed switching valve. The axial direction of the switching valve is vertical, and the sound pressure sensor records the mechanical noise generated by the collision between the movable part and the fixed part of the high-speed switching valve, and records the fluid noise caused by the impact of the fluid pressure inside the valve cavity. 3. The method for identifying faults of high-speed switching valves based on fluid noise and mechanical noise features according to claim 1, wherein: the basis for determining the type of fault includes the time domain of the high-speed switching valve collected by the sound pressure sensor Comparison of the sound pressure signal with the theoretical time domain sound pressure signal. 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 generation of the mechanical noise is caused by: when the high-speed switching valve is working, internal movable parts and fixed Collision between parts, resulting in mechanical noise; including: at the moment the valve port is closed, the internal movable parts and fixed parts of the high-speed switching valve have mechanical collision immediately, resulting in mechanical noise; when the valve port is at the maximum opening, high-speed The movable parts and fixed parts inside the switch valve collide, generating mechanical noise; The reason for the generation of the fluid noise is: the high-speed switching valve valve port causes a fluid pressure shock at the moment of opening and closing, thereby generating fluid noise; including: the high-speed switching valve transmits inertial, viscous, and compressible fluids. At the moment of closing, the fluid pressure impact does not reach the maximum. When the fluid pressure impact reaches the maximum, fluid noise is generated; when the valve port of the high-speed switching valve is closed, the time of fluid noise lags behind the mechanical noise; when the valve port is opened In an instant, the high-pressure fluid flows through the narrow valve port immediately, causing fluid pressure shock and fluid noise; , the occurrence time of mechanical noise 2 lags behind that of fluid noise 2; According to the different occurrence times of mechanical noise and fluid noise, and the different contributions of mechanical noise and fluid noise to the sound pressure level, a maximum point, three maximum points, and a maximum value appear on the sound pressure level curve of the high-speed switching valve. Point 1 corresponds to the mechanical noise generated when the valve port is closed, maximum value point 1 corresponds to fluid noise 1 when the valve port is closed, and maximum value point 2 corresponds to fluid noise 2 when the valve port is opened. Value point three corresponds to mechanical noise two when the valve port is fully opened; In the high-speed switching valve, 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 moment when mechanical noise and fluid noise appear, and the contribution of mechanical noise and fluid noise to the total noise; There are differences in the contribution of the mechanical noise and the fluid noise to the total noise, and cause the maximum and maximum values of the theoretical time-domain sound pressure signal; There are differences in the occurrence times of the mechanical noise and the fluid noise, which make the maximum value and the maximum value of the theoretical time-domain sound pressure signal different. 5. The high-speed switching valve fault identification method based on fluid noise and mechanical noise features according to claim 4, characterized in that: based on the contribution of mechanical noise and fluid noise to the theoretical time-domain sound pressure signal difference, and mechanical noise and The time difference of fluid noise generation, the theoretical time-domain sound pressure signal of the high-speed switching valve has four large sound pressure amplitudes in one cycle, the largest sound pressure amplitude is the maximum value of the theoretical time-domain sound pressure signal, and the rest The three sound pressure amplitudes are the maximum value of the theoretical time-domain sound pressure signal, respectively, the maximum value of the time-domain sound pressure signal is 1, the maximum value of the time-domain sound pressure signal is 2, and the maximum value of the time-domain sound pressure signal is 3; Compare the theoretical time-domain sound pressure signal 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 means that the high-speed switching valve is not faulty. If not, It shows that the high-speed switching valve is faulty. 6. The high-speed switching valve fault identification method based on fluid noise and mechanical noise characteristics according to claim 3, characterized in that: the high-speed switching valve event corresponding to the generation time of the maximum value of the time-domain sound pressure signal is: high-speed switching valve The moment the port is closed, the mechanical collision between the movable part and the fixed part inside the high-speed switching valve; The high-speed switching valve event corresponding to the time-domain sound pressure maximum value is due to the fluid pressure impact of the high-speed switching valve valve port closing; , the moment when the fluid pressure shock occurs when the valve port is closed lags behind the mechanical collision; The high-speed on-off valve event corresponding to the time-domain sound pressure maximum value two is due to the fluid pressure impact at the moment when the valve port of the high-speed switch valve is opened; Cause fluid pressure impact, and it takes a certain amount of time from the moment the valve port is opened to the valve port is fully opened, causing the mechanical collision when the valve port is opened to lag behind the fluid pressure impact; The high-speed switching valve event corresponding to the time-domain sound pressure maximum value three is because the valve port of the high-speed switching valve is fully opened, and the mechanical collision between the movable part and the fixed part inside the high-speed switching valve is at the maximum opening. 7. The high-speed switching valve fault identification method based on fluid noise and mechanical noise characteristics according to claim 5, characterized in that: the high-speed switching valve fault types include valve port cannot be opened, valve port cannot be closed, valve core opening and closing The frequency of the drive is inconsistent with the frequency of the PWM wave; The fault judgment feature of the failure of the valve port to open is that the sound pressure signal in the time domain is flat and has no maximum value; The fault judgment feature that the valve port cannot be closed is that the sound pressure signal in the time domain has only one maximum value; The fault judgment feature that the frequency of the spool opening and closing is inconsistent with the frequency of the driven PWM wave is that the time-domain sound pressure signal has a maximum value and three maximum values, but the frequency of the time-domain sound pressure signal and the frequency of the PWM wave Inconsistent. 8. The method for identifying faults of high-speed on-off valves based on fluid noise and mechanical noise characteristics according to claim 7, wherein the high-speed on-off valve is a normally open high-speed on-off valve. 9. The fault identification method for high-speed switching valves based on fluid noise and mechanical noise characteristics according to claim 8, characterized in that: the normally open high-speed switching valve includes a housing (1), a gasket (2), an electromagnetic coil (3), armature (4), push rod (5), valve core (6), valve seat (7), return spring (8), oil inlet port (9), oil inlet port P, working port A; When the high-speed switching valve is in operation, the electromagnetic coil is driven by PWM waves to generate electromagnetic force to push the armature to move, the armature to push the push rod to move, the push rod to push the valve core to move, and when the valve core hits 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 hits the gasket, the valve port is fully opened; The return spring keeps the armature, the push rod and the spool in contact all the time; The mechanical noise generating parts of the high-speed switching valve include the contact parts 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; 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, and the collisions of the three places occur at the same time and generate mechanical noise. At the same time, when the valve port is closed, The cavity of the oil inlet cavity changes drastically, and the fluid pressure impacts a4 in the valve cavity, resulting in fluid noise; a collision occurs at the moment when the valve port is fully opened, specifically, the contact part of the valve core and the push rod collides b3, and the push rod Collision b2 occurs at the contact part with the armature, and b1 occurs at the contact part between the armature and the gasket. The three collisions occur simultaneously and generate mechanical noise. At the same time, when the valve port is opened, high-pressure oil flows through the narrow gap of the valve port to generate fluid pressure. Impact b4, producing fluid noise two.