Self-detecting electromagnetic valve based on magnetic field intensity difference

Abstract

The application discloses a valve core sticking eccentric self-detection electromagnetic valve based on magnetic field strength difference, which comprises a valve block and a valve core; the valve core comprises a cylinder I, a cylinder II and a cylinder III; a permanent magnet is fixed to the lower half of the cylinder III; a first linear Hall element, a second linear Hall element, a third linear Hall element and a fourth linear Hall element are respectively fixed to the inner part of horizontal equidistance threaded holes; external measuring circuit I, external measuring circuit II, external measuring circuit III and external measuring circuit IV respectively measure the output voltage of the linear Hall elements, the output voltage is inversely proportional to the distance between the Hall element and the permanent magnet, the valve core drives the permanent magnet to generate vertical displacement by opening and closing, the eccentricity of the valve core drives the permanent magnet to generate horizontal displacement, the output voltage of different linear Hall elements is compared to obtain the eccentric distance and direction of the valve core, and the purpose of quickly detecting the valve core sticking state and eccentric fault is achieved.

Description

Technical Field

[0001] This invention relates to the field of solenoid valve monitoring technology, and in particular to a self-detecting solenoid valve for valve core jamming and eccentricity based on magnetic field strength difference. Background Technology

[0002] Solenoid valves are fundamental automation components used to control fluid flow, and are widely used in motion and production control of various engineering machinery and production equipment, including hydraulic and pneumatic systems. In engineering projects, failure to promptly determine whether a solenoid valve has already malfunctioned or is about to malfunction not only affects project efficiency and increases maintenance costs, but can also lead to safety accidents and property damage in severe cases. Therefore, rapid detection and prediction of solenoid valve malfunctions are extremely important.

[0003] There are many types of malfunctions in solenoid valves, but in industrial applications, the most common are liquid leakage caused by poor sealing between the valve core and valve body, and valve core jamming or seizure due to foreign objects inside the valve body. Both of these malfunctions are related to abnormal clearance between the valve core and valve sleeve. Therefore, to address these problems, this invention proposes a novel valve core jamming and eccentricity detection valve and valve block structure based on magnetic field detection, enabling real-time, non-disassembly-based detection of valve core jamming and eccentricity faults. Summary of the Invention

[0004] In view of the problems existing in the prior art, the present invention discloses a valve core jamming and eccentricity self-detection solenoid valve based on the difference of magnetic field strength, including a valve block and a valve core;

[0005] The valve core includes cylinder I, cylinder II, and cylinder III;

[0006] One end of cylinder I is integrally connected to one end of cylinder II;

[0007] The other end of cylinder II is integrally connected to cylinder III;

[0008] The radii of cylinder I and cylinder III are equal;

[0009] The radius of cylinder III is smaller than the radius of cylinder I;

[0010] The lower half of the cylinder III is fixed with a permanent magnet;

[0011] The valve block has a cylindrical cavity at its center to facilitate the longitudinal movement of the valve core.

[0012] A flow channel is horizontally provided at the middle position of the valve block;

[0013] Four horizontally spaced threaded holes, symmetrically positioned relative to the valve core, are provided on the lower half of the valve block.

[0014] A first linear Hall element, a second linear Hall element, a third linear Hall element, and a fourth linear Hall element are respectively fixed inside the horizontally equidistant threaded holes;

[0015] The first linear Hall element is connected to an external measurement circuit I;

[0016] The second linear Hall element is connected to the external measurement circuit II;

[0017] The third linear Hall element is connected to external measurement circuit III;

[0018] The fourth linear Hall element is connected to the external measurement circuit IV;

[0019] The external measurement circuits I, II, III, and IV have the same structure.

[0020] The external measurement circuits I, II, III, and IV measure the output voltage of the linear Hall element, which is inversely proportional to the distance between the Hall element and the permanent magnet. The valve core will cause the permanent magnet to produce a vertical displacement when it is opened and closed, and the eccentricity of the valve core will cause the permanent magnet to produce a horizontal displacement. By comparing the output voltages of different linear Hall elements, the eccentricity distance and direction of the valve core can be obtained, so as to achieve the purpose of rapid detection of valve core jamming and eccentricity fault.

[0021] Furthermore, the height of the cylinder I is less than the distance from the center of the flow channel to the top of the valve block.

[0022] Furthermore: the valve block shown is made of a material with low magnetic permeability, such as aluminum alloy, aluminum-magnesium alloy, stainless steel, or copper alloy.

[0023] Furthermore: the valve block shown is a cuboid.

[0024] Furthermore: the external measurement circuit I includes an external power supply for powering the first linear Hall element, a measuring resistor, and a voltmeter;

[0025] The positive pin 1 of the first linear Hall element is connected in parallel to the positive terminal of the external power supply;

[0026] The ground pin 2 of the first linear Hall element is connected in parallel to the negative terminal of the external power supply;

[0027] The output pin 3 of the first linear Hall element is connected to one end of the measuring resistor, and the other end of the measuring resistor is grounded.

[0028] The voltmeter and the measuring resistor are connected in parallel;

[0029] When powered by an external power source, the first linear Hall element outputs a voltage signal based on the magnetic field strength. The output voltage is applied to the measuring resistor and read by a voltmeter.

[0030] Furthermore, the calculation formula for the valve core sticking state is as follows:

[0031] When the solenoid valve is in a non-eccentric state, the output voltage U0 of the first Hall element is:

[0032]

[0033] When the valve core is vertically displaced, the output voltage U1 of the first Hall element is:

[0034]

[0035] According to equations (1) and (2), the displacement Δz of the permanent magnet can be derived:

[0036]

[0037] In the formula, K1 is the magnetic voltage coefficient of the linear Hall element, K2 is the magnetic field attenuation coefficient, B is the magnetic induction intensity, L is the distance between the linear Hall element and the center of the permanent magnet, l is the distance between the linear Hall element and the center of the permanent magnet projected onto the opening plane, and z is the distance between the center of the permanent magnet and the projection of the center of the permanent magnet projected onto the opening plane.

[0038] The Δz in formula (3) reflects the displacement of the valve core, that is, the degree of wear and jamming failure of the solenoid valve core.

[0039] Furthermore, the method for determining the eccentricity direction and distance of the valve core is as follows:

[0040] When the solenoid valve is in a non-eccentric state, the output voltages of external measuring circuit I, external measuring circuit II, external measuring circuit III, and external measuring circuit IV are the same, that is:

[0041] u1=u2=u3=u4 (4)

[0042] In the formula, u1 is the output voltage of the first linear Hall element, u2 is the output voltage of the second linear Hall element, u3 is the output voltage of the third linear Hall element, and u4 is the output voltage of the fourth linear Hall element;

[0043] If the output voltages of the four measuring circuits are different, then the valve core is determined to be eccentric. First, the displacement of the valve core on the line connecting the center of the first linear Hall element and the center of the third linear Hall element is calculated. When the valve core is eccentrically offset by Δl1 on this line, the output voltage u1 of the first linear Hall element is:

[0044]

[0045] The output voltage u3 of the third linear Hall element (4) is:

[0046]

[0047] According to equations (5) and (6), the eccentric displacement Δl1 in this direction can be calculated:

[0048]

[0049] Similarly, the displacement of the valve core along the line connecting the center of the second linear Hall element and the center of the fourth linear Hall element can be calculated. The eccentric displacement Δl2 of the valve core along this line is:

[0050]

[0051] Since the line connecting the centers of the first Hall element and the third Hall element is perpendicular to the line connecting the centers of the second Hall element and the fourth Hall element, the total eccentricity l of the valve core can be calculated according to the fundamental theorem of plane vectors as follows.

[0052]

[0053] By employing the above technical solution, this invention provides a self-detecting solenoid valve for valve core jamming and eccentricity based on magnetic field strength difference. The valve core and valve block integrate a linear Hall element and a permanent magnet, reducing the valve block volume. The valve block is made of a low-permeability material to ensure magnetic signal transmission. This invention utilizes a simple fault monitoring circuit to quickly calculate valve core displacement and to monitor the direction and degree of valve core eccentricity in real time by comparing the output voltages of different circuits. It has a simple structure and is easy to apply. Attached Figure Description

[0054] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0055] Figure 1 This is a schematic front view of a valve core stuck eccentric self-detection solenoid valve based on magnetic field strength difference according to the present invention.

[0056] Figure 2 This is a top view schematic diagram of a valve core jamming and eccentricity self-detection solenoid valve based on magnetic field strength difference according to the present invention.

[0057] Figure 3 This is a schematic diagram of the external measurement circuit of the present invention;

[0058] Figure 4 This is a simplified schematic diagram (I) of a valve core stuck eccentric self-detection solenoid valve based on magnetic field strength difference according to the present invention;

[0059] Figure 5 This is a simplified schematic diagram (II) of a valve core jamming and eccentricity self-detection solenoid valve based on magnetic field strength difference according to the present invention.

[0060] In the diagram: 1. Valve core, 2. Valve block, 3. Permanent magnet, 4. First linear Hall element, 5. Second linear Hall element, 6. Third linear Hall element, 7. Fourth linear Hall element, 8. External power supply, 9. Measuring resistor, 10. Voltmeter. Detailed Implementation

[0061] To make the technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention:

[0062] A valve core stuck eccentricity self-detection solenoid valve based on magnetic field strength difference includes valve block 2 and valve core 1;

[0063] The valve core 1 is made of ordinary alloy or stainless steel;

[0064] The valve core 1 includes cylinder I, cylinder II, and cylinder III;

[0065] The three cylinders, I, II, and III, belong to a single long cylindrical valve core. In terms of manufacturing, a slightly smaller cylinder II is machined near the middle of valve core I. When the solenoid valve is closed, it is normally open, and the valve core position is as follows... Figure 1 As shown, the distance from the top of cylinder I to the top of the valve body is the displacement of valve core 1. There is no specific requirement for the height of cylinder I. It is only necessary to ensure that cylinder II has part or all of its height at the same height as the valve body flow channel. Because cylinder II has a small radius, it cannot block the flow channel. The hydraulic oil or other flow medium in the flow channel can flow from the left side of the flow channel to the right side of the flow channel. At this time, the solenoid valve is turned on. The height of cylinder III must be greater than the height of the flow channel. That is, after the hydraulic valve is opened, the valve core moves upward under the action of electromagnetic force. Cylinder III needs to completely block the flow channel. At this time, the solenoid valve is not turned on. In addition, the height of cylinder III should be sufficient to open a hole for installing a permanent magnet.

[0066] One end of cylinder I is integrally connected to one end of cylinder II;

[0067] The other end of cylinder II is integrally connected to cylinder III;

[0068] The radii of cylinder I and cylinder III are equal;

[0069] The radius of cylinder III is smaller than the radius of cylinder I;

[0070] The lower half of the cylinder III is fixed with a permanent magnet 3; the permanent magnet 3 is installed and fixed through a threaded hole; thus, the displacement of the valve core 1 is equivalent to the displacement of the permanent magnet 3. In addition, the permanent magnet 3 is machined with matching external threads for easy installation.

[0071] The valve block 2 has a cylindrical cavity at its center to facilitate the longitudinal movement of the valve core 1;

[0072] A flow channel for hydraulic oil or other hydraulic medium is horizontally provided at the middle position of the valve block 2;

[0073] The lower half of the valve block 2 is provided with four horizontally equidistant threaded holes that are symmetrical about the valve core 1.

[0074] The four horizontally equidistant threaded holes are located at four positions on the same horizontal plane, one in front, one behind, one in the left, and one in the right.

[0075] A first linear Hall element 4, a second linear Hall element 5, a third linear Hall element 6, and a fourth linear Hall element 7 are respectively fixed inside the horizontally equidistant threaded holes;

[0076] The first linear Hall element 4 is connected to the external measurement circuit I;

[0077] The second linear Hall element 5 is connected to the external measurement circuit II;

[0078] The third linear Hall element 6 is connected to the external measurement circuit III;

[0079] The fourth linear Hall element 7 is connected to the external measurement circuit IV;

[0080] The external measurement circuits I, II, III, and IV have the same structure.

[0081] The external measurement circuits I, II, III, and IV measure the output voltage of the linear Hall element, which is inversely proportional to the distance between the Hall element and the permanent magnet. The opening and closing of the valve core 1 will cause the permanent magnet 3 to produce a vertical displacement, and the eccentricity of the valve core 1 will cause the permanent magnet 3 to produce a horizontal displacement. That is, the valve core displacement can be calculated by measuring the output voltage of the linear Hall element. By comparing the output voltages of different linear Hall elements, the valve core eccentricity distance and direction can be obtained, so as to achieve the purpose of rapid detection of valve core jamming and eccentricity fault.

[0082] When the solenoid valve is closed, the solenoid valve is normally open, and the valve core position is as follows: Figure 1As shown, at this time, the distance from the top of cylinder I to the top of the valve body is the displacement of the valve core switch. At this time, part of cylinder II is at the same height as the flow channel of the valve body. Because the radius of cylinder II is small, it cannot block the flow channel. The hydraulic oil or other flow medium in the flow channel can flow from the left side of the flow channel to the right side of the flow channel. At this time, the hydraulic valve is turned on, that is, after the hydraulic valve is opened, the valve core moves upward under the action of electromagnetic force. Cylinder III completely blocks the flow channel. At this time, the solenoid valve is not turned on.

[0083] Furthermore, the height of cylinder I is less than the distance from the center of the flow channel to the top of valve block 2. This is because the distance from the center of the flow channel at the center of valve core 1 to the top of valve block 2 consists of three parts, from top to bottom: a displacement for the vertical movement of cylinder I, cylinder I, and a portion of cylinder II, such as... Figure 1 As shown.

[0084] Furthermore, the valve block 2 is made of a low magnetic permeability material, such as aluminum alloy, aluminum-magnesium alloy, stainless steel, or copper alloy, to ensure the transmission of magnetic signals.

[0085] Furthermore, the valve block 2 is a cuboid.

[0086] Furthermore: the external measurement circuit I includes an external power supply 8 for powering the first linear Hall element 4, a measuring resistor 9, and a voltmeter 10;

[0087] The positive pin 1 of the first linear Hall element 4 is connected in parallel to the positive terminal of the external power supply 8;

[0088] The ground pin 2 of the first linear Hall element 4 is connected in parallel to the negative terminal of the external power supply 8;

[0089] The output pin 3 of the first linear Hall element 4 is connected to one end of the measuring resistor 9, and the other end of the measuring resistor 9 is grounded.

[0090] The resistance value of the measuring resistor 9 should be much larger than the resistance value of the wires in the test circuit, which can be several thousand ohms.

[0091] The voltmeter 10 and the measuring resistor 9 are connected in parallel.

[0092] When the first linear Hall element 4 is powered by the external power supply 8, it will output a voltage signal according to the magnetic field strength. The output voltage is applied to the measuring resistor 9 and read by the voltmeter 10.

[0093] Furthermore, the calculation formula for the stuck state of the measuring valve core 1 is as follows:

[0094] The non-eccentric state of the solenoid valve refers to the valve core not being eccentric. This excludes the possibility that valve core eccentricity would cause horizontal displacement of the permanent magnet, thus affecting the calculation of the valve core jamming state. In the non-eccentric state of the solenoid valve, the output voltage U0 of the first Hall element 4 is:

[0095]

[0096] When valve core 1 is vertically displaced, the output voltage U1 of the first Hall element (4) is:

[0097]

[0098] According to equations (1) and (2), the displacement Δz of the permanent magnet can be derived:

[0099]

[0100] In the formula, K1 is the magnetic voltage coefficient of the linear Hall element, K2 is the magnetic field attenuation coefficient, B is the magnetic induction intensity, L is the distance between the linear Hall element and the center of the permanent magnet, l is the distance between the linear Hall element and the center of the permanent magnet projected onto the opening plane, and z is the distance between the center of the permanent magnet and the projection of the center of the permanent magnet projected onto the opening plane.

[0101] The Δz in formula (3) reflects the displacement of the valve core, that is, the degree of wear and jamming failure of the solenoid valve core.

[0102] Furthermore, the method for determining the eccentricity direction and distance of the valve core 1 is as follows:

[0103] When the solenoid valve is in a non-eccentric state, the output voltages of external measuring circuit I, external measuring circuit II, external measuring circuit III, and external measuring circuit IV are the same, that is:

[0104] u1=u2=u3=u4 (4)

[0105] In the formula, u1 is the output voltage of the first linear Hall element 4, u2 is the output voltage of the second linear Hall element 5, u3 is the output voltage of the third linear Hall element 6, and u4 is the output voltage of the fourth linear Hall element 7.

[0106] If the output voltages of the four measuring circuits are different, then it is determined that the valve core 1 is eccentric. First, calculate the displacement of the valve core on the line connecting the center of the first linear Hall element 4 and the center of the third linear Hall element 6. When the valve core is eccentric Δl1 on this line, the output voltage u1 of the first linear Hall element 4 is:

[0107]

[0108] The output voltage u3 of the third linear Hall element 4 is:

[0109]

[0110] According to equations (5) and (6), the eccentric displacement Δl1 in this direction can be calculated:

[0111]

[0112] Similarly, the displacement of valve core 1 along the line connecting the center of the second linear Hall element 5 and the center of the fourth linear Hall element 7 can be calculated. The eccentric displacement Δl2 of valve core 1 along this line is:

[0113]

[0114] Since the line connecting the centers of the first and third linear Hall elements is a perpendicular bisector to the line connecting the centers of the second and fourth linear Hall elements, the total eccentricity l of the valve core can be calculated according to the fundamental theorem of plane vectors as follows:

[0115]

[0116] This invention utilizes a simple measurement circuit to quickly calculate valve core displacement and to monitor the direction and degree of valve core eccentricity in real time by comparing the output voltages of different circuits. It has a simple structure and is easy to integrate and apply.

[0117] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A self-detecting solenoid valve for valve core sticking and eccentricity based on magnetic field strength difference, characterized in that: Includes valve block (2) and valve core (1); The valve core (1) includes cylinder I, cylinder II and cylinder III; One end of cylinder I is integrally connected to one end of cylinder II; The other end of cylinder II is integrally connected to cylinder III; The radii of cylinder I and cylinder III are equal; The radius of cylinder III is smaller than the radius of cylinder I; The lower half of the cylinder III is fixed with a permanent magnet (3); The valve block (2) has a cylindrical cavity at its center to facilitate the longitudinal movement of the valve core (1); A flow channel is horizontally provided at the middle position of the valve block (2); Four horizontally spaced threaded holes, symmetrically positioned relative to the valve core (1), are provided on the lower half of the valve block (2); A first linear Hall element (4), a second linear Hall element (5), a third linear Hall element (6), and a fourth linear Hall element (7) are respectively fixed inside the horizontally equidistant threaded holes; The first linear Hall element (4) is connected to the external measurement circuit I; The second linear Hall element (5) is connected to the external measurement circuit II; The third linear Hall element (6) is connected to the external measurement circuit III; The fourth linear Hall element (7) is connected to the external measurement circuit IV; The external measurement circuits I, II, III, and IV have the same structure. The external measurement circuits I, II, III and IV measure the output voltage of the linear Hall element respectively. The output voltage is inversely proportional to the distance between the Hall element and the permanent magnet. The valve core (1) will drive the permanent magnet (3) to produce a vertical displacement when it is opened and closed. The eccentricity of the valve core (1) will drive the permanent magnet (3) to produce a horizontal displacement. By comparing the output voltages of different linear Hall elements, the eccentricity distance and direction of the valve core can be obtained, so as to achieve the purpose of rapid detection of valve core jamming and eccentricity fault.

2. The self-detecting solenoid valve for valve core jamming and eccentricity based on magnetic field strength difference as described in claim 1, further characterized in that: The height of the cylinder I is less than the distance from the center of the flow channel to the top of the valve block (2).

3. The self-detecting solenoid valve for valve core jamming and eccentricity based on magnetic field strength difference as described in claim 1, further characterized in that: The valve block (2) shown is made of a material with low magnetic permeability, such as aluminum alloy, aluminum-magnesium alloy, stainless steel or copper alloy.

4. The self-detecting solenoid valve for valve core jamming and eccentricity based on magnetic field strength difference as described in claim 1, further characterized in that: The valve block (2) shown is a cuboid.

5. The self-detecting solenoid valve for valve core jamming and eccentricity based on magnetic field strength difference according to claim 1, further characterized in that: The external measurement circuit I includes an external power supply (8) for powering the first linear Hall element, a measuring resistor (9), and a voltmeter (10); The positive pin of the first linear Hall element (4) is connected in parallel to the positive terminal of the external power supply (8); The ground pin of the first linear Hall element (4) is connected in parallel to the negative terminal of the external power supply (8); The output pin of the first linear Hall element (4) is connected to one end of the measuring resistor (9), and the other end of the measuring resistor (9) is grounded; The voltmeter (10) and the measuring resistor (9) are connected in parallel; When powered by an external power supply (8), the first linear Hall element (4) outputs a voltage signal based on the magnetic field strength. The output voltage is applied to the measuring resistor (9) and read by a voltmeter (10).

6. The self-detecting solenoid valve for valve core jamming and eccentricity based on magnetic field strength difference according to claim 1, further characterized in that: The formula for calculating the valve core sticking state is as follows: When the solenoid valve is in a non-eccentric state, the output voltage U0 of the first Hall element (4) is: When the valve core (1) is vertically displaced, the output voltage U1 of the first Hall element (4) is: According to equations (1) and (2), the displacement Δz of the permanent magnet can be derived: In the formula, K1 is the magnetic voltage coefficient of the linear Hall element, K2 is the magnetic field attenuation coefficient, B is the magnetic induction intensity, L is the distance between the linear Hall element and the center of the permanent magnet, l is the distance between the linear Hall element and the center of the permanent magnet projected onto the opening plane, and z is the distance between the center of the permanent magnet and the projection of the center of the permanent magnet projected onto the opening plane. The Δz in formula (3) reflects the displacement of the valve core, that is, the degree of wear and jamming failure of the solenoid valve core.

7. The self-detecting solenoid valve for valve core jamming and eccentricity based on magnetic field strength difference according to claim 1, further characterized in that: The method for determining the eccentricity direction and distance of the valve core (1) is as follows: When the solenoid valve is in a non-eccentric state, the output voltages of external measuring circuit I, external measuring circuit II, external measuring circuit III, and external measuring circuit IV are the same, that is: u1=u2=u3=u4 (4) In the formula, u1 is the output voltage of the first linear Hall element (4), u2 is the output voltage of the second linear Hall element (5), u3 is the output voltage of the third linear Hall element (6), and u4 is the output voltage of the fourth linear Hall element (7). If the output voltages of the four measuring circuits are different, then the valve core is determined to be eccentric. First, the displacement of the valve core on the line connecting the center of the first linear Hall element (4) and the center of the third linear Hall element (6) is calculated. When the valve core is eccentric Δl1 on this line, the output voltage u1 of the first linear Hall element (4) is: The output voltage u3 of the third linear Hall element (4) is: According to equations (5) and (6), the eccentric displacement Δl1 in this direction can be calculated: Similarly, the displacement of the valve core (1) on the line connecting the center of the second linear Hall element (5) and the center of the fourth linear Hall element (7) can be calculated. The eccentric displacement Δl2 of the valve core (1) on this line is: Since the line connecting the centers of the first Hall element and the third Hall element is perpendicular to the line connecting the centers of the second Hall element and the fourth Hall element, the total eccentricity l of the valve core can be calculated according to the fundamental theorem of plane vectors as follows.

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