A high-speed on-off valve with a spool position detection and a spool position detection method

Abstract

The application provides a high-speed switch valve with a valve core position detection and a valve core position detection method, which comprises a shell, a coil framework, an excitation coil, an induction coil, an armature, a yoke, a push rod, a valve seat, a valve core and a return spring; the excitation coil and the induction coil are wound on the fixed coil framework in the shell; the armature and the yoke are installed in the inner hole of the coil framework; the push rod slides axially in the inner hole of the yoke; one side of the push rod is in contact with the valve core, and the other side is in contact with the armature; the induction coil comprises a first induction coil and a second induction coil wound on the excitation coil; when the high-speed switch valve works, the armature drives the valve core to move through the push rod, so that the induction coil outputs a valve core position detection signal; the application can measure the displacement of the valve core of the high-speed switch valve under the conditions of oil flow and no oil flow, does not need to be connected with an expensive sensor, is more convenient to test, has lower cost, has higher precision, and is favorable for solving the problem that the displacement of the valve core of the high-speed switch valve is difficult to measure.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of intelligent digital hydraulic components, and particularly to a high-speed on-off valve with a valve core position detection and a valve core position detection method. BACKGROUND

[0002] The high-speed on-off valve is a core control component in a digital hydraulic system, which generates discrete fluid by continuous opening and closing of the valve core to achieve the control effect of continuous fluid, can greatly reduce the throttling loss of the valve control system, and improve the anti-pollution ability of the valve control system. The faster the response speed of the high-speed on-off valve is, the higher the control precision of the digital hydraulic system is. Therefore, domestic and foreign scholars are committed to studying the dynamic response characteristics of the high-speed on-off valve. However, due to the small size and compact structure of the high-speed on-off valve, the displacement of the valve core of the high-speed on-off valve is difficult to obtain directly, and thus the dynamic characteristics of the high-speed on-off valve cannot be accurately analyzed, which makes the accurate analysis of the dynamic characteristics of the high-speed on-off valve a big difficulty in the field of digital hydraulic.

[0003] In order to obtain the motion of the valve core of the high-speed on-off valve and accurately analyze the dynamic characteristics of the high-speed on-off valve, some solutions are proposed in existing researches, but there are still some deficiencies or limitations, mainly in the following aspects:

[0004] (1) The response time of the high-speed on-off valve is determined by the pressure change of the valve port. For example, the paper "High-speed on-off valve dynamic performance test device and its application research" proposes a high-speed on-off valve dynamic performance test device, which connects the working oil port of the high-speed on-off valve with a closed cavity, and estimates the action time of the high-speed on-off valve opening / closing by measuring the transient change process of the pressure of the closed cavity. The disadvantage of this method is that the pressure change of the closed cavity lags behind the motion of the valve core, and the larger the volume of the cavity is, the more serious the lag is.

[0005] (2) The response time of the high-speed on-off valve is determined by the vibration characteristics. For example, the patent CN114563175B discloses a direct detection method for dynamic characteristics of high-speed on-off valve, which connects an acceleration vibration sensor with the high-speed on-off valve in the axial direction, and uses the acceleration vibration sensor to collect the vibration signal when the valve core is opened and closed, and then determines the opening and closing state of the high-speed on-off valve. The disadvantage of this method is that the vibration signal can only determine the state of the high-speed on-off valve at the opening and closing time, and cannot detect the position change process of the valve core of the high-speed on-off valve, and other vibration interference in the test environment will cause errors in the test results.

[0006] (3) The displacement of the spool of the high-speed on-off valve is measured by a laser displacement sensor. This method leads an elongated and rigid connection from the moving parts inside the valve body to the outside of the valve body. The connection moves with the spool when the spool is opened and closed. The laser displacement sensor measures the displacement of the connection to obtain the displacement of the spool. The disadvantage of this method is that the moving parts inside the valve body need to be connected to an object, which increases the mass of the spool and adversely affects the response speed of the high-speed on-off valve. Moreover, this method can only be used when the high-speed on-off valve is not oiling.

[0007] (4) The response time of the high-speed on-off valve is determined by the inflection point of the driving current waveform of the high-speed on-off valve. Patent CN101294534B discloses a method for determining the opening and closing delay of an electromagnetic valve by using the current waveform during the driving of the electromagnetic valve. This method can only determine the electromagnetic delay and mechanical delay time of the electromagnetic valve by the inflection point of the driving current of the electromagnetic valve, and cannot detect the movement of the spool of the electromagnetic valve in real time.

[0008] In summary, the prior art can only determine the response delay time of the high-speed on-off valve, and cannot detect the movement of the spool in real time. The use of a laser displacement sensor can realize real-time detection of the displacement of the spool, but this method increases the mass of the spool and affects the response speed of the high-speed on-off valve. Moreover, this method cannot be used in the oiling condition. SUMMARY

[0009] The present application provides a high-speed on-off valve with spool position detection and a spool position detection method. The spool displacement of the high-speed on-off valve is converted into an electrical signal output using electromagnetic induction principles. This method can measure the displacement of the spool of the high-speed on-off valve in both oiling and non-oiling conditions, does not require an external expensive sensor, is more convenient to test, has lower cost, and has higher precision. This is beneficial to solving the problem of difficult measurement of the displacement of the spool of the high-speed on-off valve.

[0010] The present application adopts the following technical solutions.

[0011] A high-speed on-off valve with spool position detection, the on-off valve comprising a housing (3), a coil framework (2), an excitation coil (4), an induction coil, an armature (5), a yoke (8), a push rod (9), a valve seat (10), a spool (11), and a return spring (12);

[0012] The excitation coil and the induction coil are wound on the coil framework fixed in the housing. The armature and the yoke are installed in the inner hole of the coil framework. The yoke has an inner hole. The push rod axially slides in the inner hole of the yoke, and one side of the push rod is in contact with the spool, and the other side of the push rod is in contact with the armature;

[0013] The inductive coils include a first inductive coil (6) and a second inductive coil (7); the two inductive coils are arranged in sequence on the outer side of the excitation coil in the axial direction of the coil framework, or are separately arranged on the side of the two end faces of the excitation coil; when the high-speed on-off valve works, under the electromagnetic force driving of the excitation coil and the yoke, the armature moves the valve core through the push rod, so that the inductive coil outputs the valve core position detection signal.

[0014] The working form of the high-speed on-off valve is a two-position two-way type, the valve seat is connected with the shell, an oil hole is arranged at the valve seat, the valve core and the reset spring are arranged in the valve seat, and the reset spring is used for resetting the valve core.

[0015] The first inductive coil and the second inductive coil are not connected with the excitation coil.

[0016] The initial position of the armature is located at the center line in the axial direction of the excitation coil.

[0017] When the armature moves the valve core through the push rod, the displacement of the armature is equal to the displacement of the valve core, and the change value of the displacement of the armature can be regarded as the change value of the displacement of the valve core.

[0018] The first inductive coil and the second inductive coil are symmetrically distributed along the center line in the axial direction of the excitation coil, and are distributed in the axial direction of the coil framework; the first inductive coil and the second inductive coil are reversely connected in series.

[0019] The first inductive coil and the second inductive coil have the same number of turns, the same length and the same diameter, and have the same resistance value and the same inductance value.

[0020] A valve core position detection method of a high-speed on-off valve with valve core position detection, which is used for the high-speed on-off valve with valve core position detection described above, and is characterized in that: the method drives the movement of the valve core of the high-speed on-off valve by a control circuit powered by a voltage source, and processes the output signal of the first inductive coil and the second inductive coil reversely connected in series of the high-speed on-off valve by a signal processing module to obtain a valve core displacement curve; the method specifically includes the following steps.

[0021] Step S1: the voltage source supplies power to the control circuit;

[0022] Step S2: the control circuit outputs a control voltage according to specific control requirements to excite the excitation coil of the high-speed on-off valve;

[0023] Step S3: the first inductive coil and the second inductive coil of the high-speed on-off valve are reversely connected in series and then connected to the signal processing module;

[0024] Step S4: when the armature drives the valve core to move, the movement of the armature in the induction coil generates an induced electromotive force, and the signal processing module converts the received induced electromotive force difference value of the induction coil into a corresponding valve core displacement signal;

[0025] The input signal of the signal processing module is the induced electromotive force difference value signal output by the first induction coil and the second induction coil in reverse series, the output signal of the signal processing module is the valve core displacement signal, and the signal processing module stores a function relationship corresponding to the induced electromotive force difference value signal and the valve core displacement signal.

[0026] When the switch valve works, the excitation coil drives the high-speed switch valve to move and generates a changing magnetic field, thereby generating an induced electromotive force at the induction coil, and the excitation coil is externally connected to a control circuit; the total electromotive force output by the first induction coil and the second induction coil after being connected in reverse series is the difference between the induced electromotive forces of the two induction coils, the armature is located in the magnetic path of the induction coil, and the change of the position of the armature causes the difference between the induced electromotive forces of the two induction coils to change, that is, there is a function relationship between the difference between the induced electromotive forces of the induction coil and the displacement of the armature, the first induction coil and the second induction coil are connected in reverse series and then connected to the signal processing module, and the valve core displacement is calculated through the signal processing module; specifically:

[0027] When the voltage source applies a voltage excitation to the excitation coil, the current in the excitation coil changes, and in this process, a magnetic field is established in the coil due to the change of the current, and the armature is located in the magnetic path of the coil, and the change of the position of the armature causes the difference between the induced electromotive forces of the two induction coils to change;

[0028] The excitation coil and the induction coil are regarded as a circuit in which a resistor and an inductor are connected in series, and the voltage balance equation of the excitation coil is:

[0029]

[0030] The current in the excitation coil is:

[0031]

[0032] In the formula, U0 is the excitation voltage of the excitation coil, I0 is the current of the excitation coil, and R0 is the resistance of the excitation coil;

[0033] The magnetic flux generated by the first induction coil and the second induction coil can be expressed by the formula

[0034]

[0035] In the formula, φ1 is the magnetic flux of the first induction coil, φ2 is the magnetic flux of the second induction coil, N0 is the number of turns of the excitation coil, I0 is the current of the excitation coil, R m1 is the magnetic resistance of the first induction coil, and Rm2 The magnetic reluctance of the second induction coil;

[0036] The magnetic reluctance of the first induction coil and the second induction coil is expressed by the formula as follows:

[0037]

[0038] In the formula, l i represents the length of the magnetic flux path of the magnetic conductor, μ i represents the permeability of the magnetic conductor, S i represents the cross-sectional area of the magnetic flux path of the magnetic conductor, δ represents the length of the air gap path, μ0 represents the vacuum permeability, and S0 represents the cross-sectional area of the air gap.

[0039] The induced electromotive force of the first induction coil and the second induction coil is expressed by the formula as follows:

[0040]

[0041] In the formula, M1 is the mutual inductance of the excitation coil and the first induction coil, and M2 is the mutual inductance of the excitation coil and the second induction coil.

[0042]

[0043] In the formula, N1 is the number of turns of the first induction coil, N2 is the number of turns of the second induction coil, and N1=N2=N i

[0044] After the first induction coil and the second induction coil are connected in reverse series, the output voltage is the difference between the induced electromotive forces, which is expressed by the formula as follows:

[0045]

[0046] Assuming that the quality factor of the excitation coil can make R0<<ωL0, formula (2) and (6) are brought in to obtain:

[0047]

[0048] When the armature moves Δx, then:

[0049]

[0050] From formula (9), it can be seen that the difference between the induced electromotive forces of the first induction coil and the second induction coil is linearly related to the displacement of the armature.

[0051] ​When the armature is in the middle initial position, if the two inductive coil parameters and the magnetic circuit size are equal, M1=M2, the initial induced electromotive force difference value is 0; when the armature position changes and affects the magnetic flux change through the inductive coil, and then the mutual inductance of the inductive coil close to the armature side is greater than that of the other side, at this time M1≠M2, the induced electromotive force difference value of the two inductive coils after reverse series connection changes, and the physical displacement change measurement signal based on the electric-magnetic field coupling change relationship is formed.

[0052] The function relationship between the induced electromotive force difference value signal and the valve displacement signal is obtained by least square algorithm fitting, and the fitting is carried out according to the following steps:

[0053] Step A1: Collect experimental data (x i , y i ) for fitting, wherein x i is the displacement of the valve core, and y i is the induced electromotive force difference value; the simulation data can also be used for fitting;

[0054] Step A2: Determine the form of the regression equation; when the induced electromotive force difference value signal and the displacement signal are approximately linear, set the regression equation as y=ax+b;

[0055] Step A3: Calculate the distance of each data point to the regression straight line, and calculate the square value of the distance;

[0056] Step A4: Sum all the square distances to obtain the residual sum of squares;

[0057] Step A5: Determine the value of the unknown parameter in the regression equation to minimize the residual sum of squares;

[0058] Step A6: Substitute the determined value of the unknown parameter into the regression equation to obtain the function relationship between the induced electromotive force difference value and the displacement of the valve core;

[0059] After obtaining the function relationship between the induced electromotive force difference value and the displacement of the valve core when the valve core is opened and reset through the above steps, the collected induced electromotive force difference value signal is converted by using the function relationship to obtain the corresponding displacement of the valve core.

[0060] Compared with the existing valve core displacement detection technology of high-speed on-off valve, the electromagnetic induction principle is used to measure the displacement of the valve core of the high-speed on-off valve, without increasing the mass of the valve core, the response speed is faster, the hysteresis is small, and the real-time monitoring of the displacement of the valve core of the high-speed on-off valve can be realized in the oil passing and non-oil passing working conditions. BRIEF DESCRIPTION OF DRAWINGS

[0061] The application will be further described in detail below in combination with the drawings and specific embodiments:

[0062] FIG.Figure 1 is the schematic diagram of the induction coil installation of the present application;

[0063] attached Figure 2 is the schematic diagram of the induction coil connection of the present application;

[0064] attached Figure 3 schematic diagram of the structure of the embodiment of the present application;

[0065] attached Figure 4 is the schematic diagram of the connection of the valve core displacement detection system of the embodiment of the present application;

[0066] attached Figure 5 is the simulation schematic diagram of the relationship between the difference of the induced electromotive force of the induction coil and the displacement of the valve core;

[0067] In the figure: 1-end cover; 2-coil skeleton; 3-housing; 4-excitation coil; 5-armature; 6-first induction coil; 7-second induction coil; 8-yoke; 9-push rod; 10-valve seat; 11-valve core; 12-return spring; 13-voltage source; 14-control circuit; 15-high-speed on-off valve with valve core position detection; 16-signal processing module. DETAILED DESCRIPTION

[0068] As shown in the figure, a high-speed on-off valve with valve core position detection, the on-off valve comprising a housing 3, a coil skeleton 2, an excitation coil 4, an induction coil, an armature 5, a yoke 8, a push rod 9, a valve seat 10, a valve core 11, and a return spring 12;

[0069] The coil skeleton fixed in the housing is wound with the excitation coil and the induction coil, the armature and the yoke are installed in the inner hole of the coil skeleton, the yoke is provided with an inner hole, the push rod axially slides in the inner hole of the yoke, one side of the push rod is in contact with the valve core, and the other side is in contact with the armature;

[0070] The induction coil comprises a first induction coil 6 and a second induction coil 7; the two induction coils are arranged in the axial direction of the coil skeleton and are sequentially arranged outside the excitation coil (as shown in a of Figure 1 ), or are separately arranged beside the two end faces of the excitation coil (as shown in b of Figure 1 ); when the high-speed on-off valve works, the armature is driven by the electromagnetic force of the excitation coil and the yoke, the valve core is pushed by the push rod to move, and the induction coil outputs the valve core position detection signal.

[0071] The working form of the high-speed on-off valve is two-position two-way, the valve seat is connected with the housing, an oil hole is arranged at the valve seat, the valve core and the return spring are installed inside the valve seat, the return spring is used for resetting the valve core, and one end of the housing is connected with the end cover 1.

[0072] The first induction coil and the second induction coil are not connected with the excitation coil.

[0073] The initial position of the armature is located at the center line of the axial direction of the exciting coil.

[0074] When the armature drives the spool to move, the displacement of the armature is equal to the displacement of the spool, and the change value of the displacement of the armature can be regarded as the change value of the displacement of the spool.

[0075] The first and second induction coils are symmetrically distributed along the center line of the axial direction of the exciting coil and are distributed along the axial direction of the coil framework; and the first and second induction coils are reversely connected in series.

[0076] The first and second induction coils have the same number of turns, the same length, and the same diameter, and have the same resistance value and the same inductance value.

[0077] A spool position detection method of a high-speed on-off valve with spool position detection, for the high-speed on-off valve 15 with spool position detection described above, characterized in that the method drives the spool movement of the high-speed on-off valve by a control circuit 14 powered by a voltage source 13, and processes data of the output signal of the first and second induction coils of the high-speed on-off valve reversely connected in series by a signal processing module 16 to obtain a spool displacement curve; and specifically includes the following steps:

[0078] Step S1: the voltage source powers the control circuit;

[0079] Step S2: the control circuit outputs a control voltage according to specific control requirements to excite the exciting coil of the high-speed on-off valve;

[0080] Step S3: the first and second induction coils of the high-speed on-off valve reversely connected in series are connected to the signal processing module;

[0081] Step S4: when the armature drives the spool to move, the movement of the armature in the induction coil causes the induction coil to generate an induced electromotive force, and the signal processing module converts the received difference value of the induced electromotive force of the induction coil into a corresponding spool displacement signal;

[0082] The input signal of the signal processing module is the difference value signal of the induced electromotive force output by the first and second induction coils reversely connected in series, the output signal of the signal processing module is the spool displacement signal, and the signal processing module stores a function relationship corresponding to the difference value signal of the induced electromotive force and the spool displacement signal.

[0083] When the switch valve works, the excitation coil drives the high-speed switch valve to move and generates a changing magnetic field, thereby generating an induced electromotive force at the induction coil, and the excitation coil is externally connected to a control circuit; the total electromotive force output by the first induction coil and the second induction coil after being connected in reverse series is the difference between the induced electromotive forces of the two induction coils, the armature is located in the magnetic path of the induction coil, and the change of the position of the armature causes the difference between the induced electromotive forces of the two induction coils to change, that is, there is a functional relationship between the difference between the induced electromotive forces of the induction coils and the displacement of the armature, the first induction coil and the second induction coil are connected in reverse series and connected to a signal processing module, and the displacement of the valve core is calculated through the signal processing module; specifically:

[0084] When the voltage source applies voltage excitation to the excitation coil, the current in the excitation coil changes, and in this process, a magnetic field is established in the coil due to the change of the current, and the armature is located in the coil magnetic path, and the change of the position of the armature will cause the difference between the induced electromotive forces of the two induction coils to change;

[0085] The excitation coil and the induction coil are regarded as a circuit in which resistance and inductance are connected in series, and the voltage balance equation of the excitation coil is:

[0086]

[0087] The current in the excitation coil is:

[0088]

[0089] In the formula, U0 is the excitation voltage of the excitation coil; I0 is the current of the excitation coil; R0 is the resistance of the excitation coil;

[0090] The magnetic flux generated by the first induction coil and the second induction coil is expressed by the formula

[0091]

[0092] In the formula, φ1 is the magnetic flux of the first induction coil; φ2 is the magnetic flux of the second induction coil; N0 is the number of turns of the excitation coil; I0 is the current of the excitation coil; R m1 is the magnetic resistance of the first induction coil; R m2 is the magnetic resistance of the second induction coil;

[0093] The magnetic resistance of the first induction coil and the second induction coil is expressed by the formula

[0094]

[0095] In the formula, l i represents the length of the magnetic flux path of the magnetic conductor, μ i represents the magnetic permeability of the magnetic conductor, and S irepresents the cross-sectional area of the magnetic flux path of the magnetic conductor, δ represents the length of the air gap path, μ0 represents the vacuum permeability, and S0 represents the cross-sectional area of the air gap;

[0096] The induced electromotive forces of the first and second induction coils are expressed by the following formula:

[0097]

[0098] In the formula, M1 represents mutual inductance of the excitation coil and the first induction coil, and M2 represents mutual inductance of the excitation coil and the second induction coil.

[0099]

[0100] In the formula, N1 represents the number of turns of the first induction coil, N2 represents the number of turns of the second induction coil, and N1=N2=N i .

[0101] After the first and second induction coils are connected in reverse series, the output voltage is the difference between the induced electromotive forces, which is expressed by the following formula:

[0102]

[0103] Assuming that the quality factor of the excitation coil can make R0<<ωL0, formula (2) and (6) are brought in to obtain:

[0104]

[0105] When the armature moves Δx, then:

[0106]

[0107] It is known from formula (9) that the difference between the induced electromotive forces of the first and second induction coils is linearly related to the displacement of the armature.

[0108] When the armature is at the initial middle position, if the parameters of the two induction coils and the sizes of the magnetic circuits are equal, M1=M2, and the initial difference between the induced electromotive forces is 0. When the position of the armature changes and affects the change in the magnetic flux passing through the induction coils, the mutual inductance of the induction coil close to the armature is greater than that of the other side, and at this time, M1≠M2. The difference between the induced electromotive forces output by the two induction coils connected in reverse series changes, forming a physical displacement change measurement signal based on the change relationship of the electric-magnetic field coupling.

[0109] The functional relationship between the difference between the induced electromotive forces and the valve displacement signal is obtained by least square fitting, and the fitting is performed according to the following steps:

[0110] Step A1: Collecting experimental data x i , yi , where x i It is the valve core displacement, y i It is the induced electromotive force difference value; it can also be used for fitting through simulation data;

[0111] Step A2: Determine the form of the regression equation; when the induced electromotive force difference signal and the displacement signal are approximately linearly related, set the regression equation as y = ax + b;

[0112] Step A3: Calculate the distance from each data point to the regression line, and calculate the square of the distance;

[0113] Step A4: Sum all squared distances to obtain the residual sum of squares;

[0114] Step A5: Determine the values ​​of the unknown parameters in the regression equation that minimize the sum of squared residuals;

[0115] Step A6: Substitute the determined values ​​of the unknown parameters into the regression equation to obtain the functional relationship between the induced electromotive force difference and the valve core displacement;

[0116] After obtaining the functional relationship between the induced electromotive force difference of the induction coil and the valve core displacement when the valve core is opened and reset through the above steps, the collected induced electromotive force difference signal is converted using this functional relationship to obtain the corresponding valve core displacement.

[0117] Example:

[0118] like Figure 3 As shown, this embodiment provides a high-speed switching valve with valve core position detection, which operates in a two-position two-way manner. The high-speed switching valve with valve core position detection consists of an end cap 1, a coil frame 2, a housing 3, an excitation coil 4, an armature 5, a first induction coil 6, a second induction coil 7, a yoke 8, a push rod 9, a valve seat 10, a valve core 11, and a return spring 12. The end cap 1 is connected to the housing 3. The excitation coil 4 is wound on the coil frame 2, and the first induction coil 6 and the second induction coil 7 are wound radially outward from the excitation coil 4. It should be noted that the excitation coil and the induction coils do not contact each other. The armature 5 and the yoke 8 are installed in the inner hole of the coil frame 2. The yoke 8 has an inner hole, and the push rod 9 slides axially in the inner hole of the yoke 8. One side of the push rod 9 contacts the valve core 11, and the other side contacts the armature 5. The valve seat 10 is connected to the housing 3, and an oil hole is provided on the valve seat 10. The valve core 11 and the return spring 12 are installed inside the valve seat 10.

[0119] The first induction coil 6 and the second induction coil 7 are distributed along the axial direction of the coil frame 2. In this embodiment, the first induction coil 6 is installed to the left of the second induction coil 7, and the first induction coil 6 and the second induction coil 7 are installed radially outside the excitation coil, as shown below. Figure 1As shown by a in the figure, the two induction coils are symmetrically distributed about the axial center line of the exciting coil 4, and the axial center line of the exciting coil 4 is as shown by a dashed line in the figure. Figure 3 As shown by a dashed line in the figure.

[0120] The first induction coil 6 and the second induction coil 7 have the same number of turns, the same length and diameter, and the same resistance and inductance.

[0121] The first induction coil 6 and the second induction coil 7 are reversely connected in series, that is, the like-named ends of the two coil windings are connected, and the purpose is to make the total electromotive force output the difference between the electromotive forces of the two coil windings.

[0122] The initial position of the armature 5 is located at the axial center line of the exciting coil, and when the high-speed on-off valve is working, the armature 5 pushes the valve core 11 to move through the push rod 9, so the displacement of the armature is equal to the displacement of the valve core, and the purpose of detecting the displacement of the valve core can be achieved by detecting the change of the displacement of the armature.

[0123] As shown in the figure, Figure 4 As shown in the figure, a valve core displacement detection system connection diagram of the valve core position detection high-speed on-off valve is provided, which is composed of a voltage source 13, a control circuit 14, a valve core position detection high-speed on-off valve 15, and a signal processing module 16; the voltage source 13 is used to power the control circuit 14; the control circuit 14 is used to drive the valve core position detection high-speed on-off valve 15 to move; and the signal processing module 16 is used to process the output signal of the reversely connected first induction coil 6 and second induction coil 7 of the high-speed on-off valve to obtain a valve core displacement curve.

[0124] The exciting coil needs to drive the high-speed on-off valve to move and generate a changing magnetic field, so as to generate an induced electromotive force at the induction coil, and therefore the exciting coil needs to be externally connected to a control circuit; the total electromotive force output by the two induction coils after being reversely connected in series is the difference between the induced electromotive forces of the two induction coils, and since the armature is in the coil magnetic path, the change of the position of the armature will cause the difference between the induced electromotive forces of the two induction coils to change, that is, there is a certain functional relationship between the difference between the induced electromotive forces of the induction coils and the displacement of the armature, and therefore the first induction coil 6 and the second induction coil 7 are reversely connected in series and connected to the signal processing module 16, and the valve core displacement can be calculated through the signal processing module.

[0125] When the voltage source applies voltage excitation to the exciting coil, the current in the exciting coil changes, and in this process, a magnetic field is established in the coil due to the change of the current, and since the armature is in the coil magnetic path, the change of the position of the armature will cause the difference between the induced electromotive forces of the two induction coils to change.

[0126] The exciting coil and the induction coil are regarded as a circuit in which resistance and inductance are connected in series, and the voltage balance equation of the exciting coil is:

[0127]

[0128] The current in the excitation coil is:

[0129]

[0130] wherein U0 is the excitation voltage of the excitation coil; I0 is the current of the excitation coil; R0 is the resistance of the excitation coil;

[0131] The magnetic flux generated by the first and second induction coils is expressed by the formula

[0132]

[0133] wherein φ1 is the magnetic flux of the first induction coil; φ2 is the magnetic flux of the second induction coil; N0 is the number of turns of the excitation coil; I0 is the current of the excitation coil; R m1 is the magnetic resistance of the first induction coil; R m2 is the magnetic resistance of the second induction coil;

[0134] The magnetic resistance of the first and second induction coils is expressed by the formula

[0135]

[0136] wherein l i represents the length of the magnetic flux path of the magnetic conductor, μ i represents the magnetic permeability of the magnetic conductor, S i represents the cross-sectional area of the magnetic flux path of the magnetic conductor, δ represents the length of the air gap path, μ0 represents the vacuum permeability, and S0 represents the cross-sectional area of the air gap;

[0137] The induced electromotive force of the first and second induction coils is expressed by the formula

[0138]

[0139] wherein M1 is the mutual inductance between the excitation coil and the first induction coil; M2 is the mutual inductance between the excitation coil and the second induction coil;

[0140]

[0141] wherein N1 is the number of turns of the first induction coil; N2 is the number of turns of the second induction coil; N1 = N2 = N i ;

[0142] After the first and second induction coils are connected in reverse series, the output voltage is the difference between the induced electromotive forces, which is expressed by the formula

[0143]

[0144] Assuming the quality factor of the excitation coil can make R0<<ωL0, formula (2), (6) is brought in, and the following can be obtained:

[0145]

[0146] When the armature moves Δx, then:

[0147]

[0148] It is known from formula (9) that the difference between the induced electromotive forces of the first and second induction coils is linearly related to the displacement of the armature;

[0149] When the armature is at the initial middle position, if the parameters and the magnetic circuit size of the two induction coils are ensured to be equal, M1=M2, and the initial difference between the induced electromotive forces is 0; when the position of the armature changes, the change in the magnetic flux passing through the induction coils is affected, and the mutual inductance of the induction coil close to the armature is greater than that of the other side, at this time M1≠M2, the difference between the induced electromotive forces output by the two induction coils after being connected in reverse series changes. According to the above principle and the induction process, the purpose of measuring the physical displacement change can be achieved by using the change relationship between the electric field and the magnetic field.

[0150] Figure 5 The simulation diagram of the difference between the induced electromotive forces of the first and second induction coils 6 and 7 and the displacement of the valve core in the embodiment is shown, curve 1 is the curve of the difference between the induced electromotive forces and the displacement of the valve core when the valve core is opened (the valve core moves from 0 mm to 0.2 mm); curve 2 is the curve of the difference between the induced electromotive forces and the displacement of the valve core when the valve core is reset (the valve core moves from 0.2 mm to 0 mm); in the embodiment, since the magnetic circuit size of the first and second induction coils is not completely equal, the difference between the induced electromotive forces when the valve core just starts to move is not zero, as can be seen from the figure, during the opening and resetting movement of the valve core, the relationship between the difference between the induced electromotive forces of the first and second induction coils 6 and 7 and the displacement of the valve core is approximately linear, therefore, after fitting the relationship between the induced electromotive force difference and the displacement of the valve core, the displacement of the valve core can be detected through the induced electromotive force difference of the first and second induction coils 6 and 7;

[0151] The specific detection process is carried out according to the following steps:

[0152] Step S1: The voltage source supplies power to the control circuit;

[0153] Step S2: The control circuit outputs a control voltage according to the specific control requirement to excite the excitation coil of the high-speed on-off valve;

[0154] Step S3: The first and second induction coils of the high-speed on-off valve are connected in reverse series and connected to the signal processing module.

[0155] Step S4: The signal processing module converts the received induced electromotive force difference value into a corresponding spool displacement signal;

[0156] The signal processing module internally contains a function relationship between the induced electromotive force difference value signal and the displacement signal, and the function relationship between the induced electromotive force difference value signal and the displacement signal is fitted by a least square algorithm, and the fitting is performed according to the following steps:

[0157] Step S1: Collect a set of experimental data (x i , y i ), wherein x i is the spool displacement, y i is the induced electromotive force difference value, and in this embodiment, simulation data is used for fitting;

[0158] Step S2: Determine the form of the regression equation, in this embodiment, it can be seen from the simulation curve that the induced electromotive force difference value signal and the displacement signal have an approximate linear relationship, so the regression equation y = ax + b can be set;

[0159] Step S3: Calculate the distance of each data point to the regression straight line, and calculate the square value of the distance;

[0160] Step S4: Sum all the squared distances to obtain the residual sum of squares;

[0161] Step S5: Determine the value of the unknown parameter in the regression equation to minimize the residual sum of squares;

[0162] Step S6: Substitute the determined value of the unknown parameter into the regression equation to obtain the function relationship between the induced electromotive force difference value and the spool displacement.

[0163] Through the above steps, the function relationship between the induced electromotive force difference value of the induction coil and the spool displacement when the spool is opened and reset can be obtained, and the collected induced electromotive force difference value signal can be converted to obtain the corresponding spool displacement.

[0164] The above is only a preferred embodiment of the present application, and is not intended to limit the present application in other forms. Any skilled person in the art can modify or change the above disclosed technical content to obtain equivalent embodiments. However, any simple modification, equivalent change and modification of the above embodiments without departing from the technical solution of the present application, and according to the technical essence of the present application, still belongs to the protection scope of the present application.

Claims

1. A high-speed switching valve with valve core position detection, characterized in that: The switching valve includes a housing (3), a coil frame (2), an excitation coil (4), an induction coil, an armature (5), a yoke (8), a push rod (9), a valve seat (10), a valve core (11), and a return spring (12); An excitation coil and an induction coil are wound on a coil skeleton fixed inside the housing. The armature and yoke are installed in the inner hole of the coil skeleton. The yoke has an inner hole. The push rod slides axially in the inner hole of the yoke. One side of the push rod contacts the valve core, and the other side contacts the armature. The induction coil includes a first induction coil (6) and a second induction coil (7); the two induction coils are arranged sequentially on the outside of the excitation coil in the axial direction of the coil frame, or placed on the sides of the two end faces of the excitation coil; when the high-speed switching valve is working, under the electromagnetic force of the excitation coil and the yoke, the armature pushes the valve core to move through the push rod, so that the induction coil outputs the valve core position detection signal; The first induction coil and the second induction coil are symmetrically distributed along the center line of the excitation coil axis, and also distributed along the axial direction of the coil frame; the first induction coil and the second induction coil are connected in reverse series. The first and second induction coils have the same number of turns, the same length, the same diameter, the same resistance, and the same inductance.

2. A high-speed switching valve with valve core position detection according to claim 1, characterized in that: The high-speed switching valve operates in a two-position two-way manner. Its valve seat and outer shell are connected, and an oil hole is opened at the valve seat. The valve core and the return spring are installed inside the valve seat. The return spring is used to reset the valve core. One end of the outer shell is connected to the end cover (1).

3. A high-speed switching valve with valve core position detection according to claim 1, characterized in that: Neither the first induction coil nor the second induction coil is connected to the excitation coil.

4. A high-speed switching valve with valve core position detection according to claim 1, characterized in that: The initial position of the armature is located at the center line of the excitation coil axis.

5. A high-speed switching valve with valve core position detection according to claim 1, characterized in that: When the armature pushes the valve core to move through the push rod, the armature displacement is equal to the valve core displacement, and the change in armature displacement is regarded as the change in valve core displacement.

6. A method for detecting the valve core position of a high-speed switching valve with valve core position detection, used in the high-speed switching valve with valve core position detection as described in claim 1, characterized in that: The method uses a control circuit powered by a voltage source to drive the valve core of a high-speed switching valve, and a signal processing module to process the output signals of the first and second induction coils of the high-speed switching valve in reverse series to obtain the valve core displacement curve; specifically, it includes the following steps; Step S1: The voltage source supplies power to the control circuit; Step S2: The control circuit outputs a control voltage according to the specific control requirements to excite the excitation coil of the high-speed switching valve; Step S3: The first and second induction coils of the high-speed switching valve are connected in reverse series and then connected to the signal processing module. Step S4: When the armature drives the valve core to move, the movement of the armature in the induction coil causes the induction coil to generate an induced electromotive force. The signal processing module converts the received difference in induced electromotive force of the induction coil into the corresponding valve core displacement signal. The input signal of the signal processing module is the induced electromotive force difference signal output by the first induction coil and the second induction coil in reverse series, and the output signal of the signal processing module is the valve core displacement signal. The signal processing module stores the functional relationship between the induced electromotive force difference signal and the valve core displacement signal.

7. The valve core position detection method for a high-speed switching valve with valve core position detection according to claim 6, characterized in that: When the switching valve is working, the excitation coil drives the high-speed switching valve to move and generates a changing magnetic field, thereby generating an induced electromotive force (EMF) at the induction coil. The excitation coil is externally connected to a control circuit. The total EMF output by the first and second induction coils after being connected in reverse series is the difference between the induced EMFs of the two induction coils. The armature is located in the magnetic circuit path of the induction coil. The change in the position of the armature causes a change in the difference between the induced EMFs of the two induction coils. That is, there is a functional relationship between the difference in the induced EMFs of the induction coils and the displacement of the armature. The first and second induction coils are connected in reverse series and then connected to a signal processing module. The signal processing module calculates the valve core displacement. Specifically: When the voltage source applies voltage excitation to the excitation coil, the current in the excitation coil changes. During this process, the change in current will establish a magnetic field in the coil, and the armature is in the magnetic circuit path of the coil. The change in the position of the armature will cause the difference in induced electromotive force between the two induction coils to change. If we consider the excitation coil and the induction coil as a circuit consisting of a resistor and an inductor connected in series, then the voltage balance equation for the excitation coil is: The current in the excitation coil is: In the formula: U0 is the excitation voltage of the excitation coil; I0 is the current of the excitation coil; R0 is the resistance of the excitation coil; The magnetic flux generated by the first and second induction coils can be expressed by the formula: In the formula: φ1 is the magnetic flux of the first induction coil; φ2 is the magnetic flux of the second induction coil; N0 is the number of turns of the excitation coil; I0 is the current of the excitation coil; R m1 R is the magnetic reluctance of the first induction coil; m2 The magnetic reluctance of the second induction coil; The magnetic reluctance of the first and second induction coils is given by the following formula: In the formula, l i μ represents the length of the magnetic flux path of the magnetic conductor. i S represents the permeability of a magnetic material. i δ represents the cross-sectional area of ​​the magnetic flux path of the magnetic conductor, δ represents the length of the air gap path, μ0 represents the permeability of free space, and S0 represents the cross-sectional area of ​​the air gap. The induced electromotive force of the first and second induction coils can be expressed by the following formula: In the formula: M1 is the mutual inductance between the excitation coil and the first induction coil; M2 is the mutual inductance between the excitation coil and the second induction coil; In the formula: N1 is the number of turns of the first induction coil; N2 is the number of turns of the second induction coil; N1 = N2 = N i ; When the first and second induction coils are connected in reverse series, their output voltage is the difference in induced electromotive force, which can be expressed by the formula: Assuming the quality factor of the excitation coil is such that R0 << ωL0, substituting equations (2) and (6) into the equations, we get: When the armature moves by Δx, then: From formula (9), we know that the difference in induced electromotive force between the first induction coil and the second induction coil is linearly related to the armature displacement; When the armature is in the initial middle position, if the parameters and magnetic circuit dimensions of the two induction coils are equal, then M1 = M2, and the initial induced electromotive force difference is 0. When the position of the armature changes, it affects the change in magnetic flux passing through the induction coils, which in turn makes the mutual inductance between the induction coil closer to the armature side greater than that between the two sides. At this time, M1 ≠ M2. After the two induction coils are connected in reverse series, the induced electromotive force difference output changes, forming a physical displacement change measurement signal based on the change relationship of electric-magnetic field coupling.

8. The valve core position detection method for a high-speed switching valve with valve core position detection according to claim 6, characterized in that: The functional relationship between the induced electromotive force difference signal and the valve displacement signal is obtained by fitting using a least squares algorithm. The fitting is performed according to the following steps: Step A1: Collect experimental data (x) for fitting. i y i ), where x i It is the valve core displacement, y i It is the induced electromotive force difference value; it is used for fitting through simulation data; Step A2: Determine the form of the regression equation; When the induced electromotive force difference signal and the displacement signal are approximately linearly related, the regression equation is set as y = ax + b; Step A3: Calculate the distance from each data point to the regression line, and calculate the square of the distance; Step A4: Sum all squared distances to obtain the residual sum of squares; Step A5: Determine the values ​​of the unknown parameters in the regression equation that minimize the sum of squared residuals; Step A6: Substitute the determined values ​​of the unknown parameters into the regression equation to obtain the functional relationship between the induced electromotive force difference and the valve core displacement; After obtaining the functional relationship between the induced electromotive force difference of the induction coil and the valve core displacement when the valve core is opened and reset through the above steps, the collected induced electromotive force difference signal is converted using this functional relationship to obtain the corresponding valve core displacement.

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