Proportional valve capable of reducing hysteresis and design method thereof

Abstract

The invention provides a proportional valve capable of reducing hysteresis and a design method of the proportional valve, belongs to the technical field of valves, and solves the problems that a spring in an existing proportional valve is high in machining difficulty and low in reliability. One end of the shell is in threaded connection with an end cover, the other end of the shell is in threaded connection with a valve sleeve, a valve element assembly is movably arranged in the shell, a spring is arranged between the valve element assembly and the end cover, a coil assembly is arranged in the shell, an air inlet nozzle is fixedly installed in the valve sleeve, and a guide cylinder assembly is arranged between the coil assembly and the valve element assembly. And a non-magnetic layer is arranged on the end surface of the end cover. The air gap length of the proportional valve is increased, the high magnetic induction section of the air gap length is designed to be made of a non-magnetic-conductive material, it is guaranteed that the proportional valve works in a low magnetic induction intensity interval in the working air gap, the levelness of an electromagnetic force curve in the interval is good, and the force value is basically unchanged, so that the spring meeting the requirement is more easily matched, and the electromagnetic force and the spring force meet the balance requirement; therefore, the hysteresis of the proportional valve is reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of valves, in particular to a proportional valve with reduced hysteresis and a design method thereof. BACKGROUND

[0002] The proportional valve is a hydraulic or pneumatic control element for continuously adjusting fluid flow, pressure or direction through an electrical signal. The proportional valve replaces the original control part of the ordinary pressure valve, flow valve and directional valve with a proportional electromagnet, and continuously and proportionally controls the pressure, flow or direction of the oil flow according to the input electrical signal. The core is to convert the input electrical signal into mechanical movement in proportion, so as to realize accurate control of fluid parameters.

[0003] At present, the hysteresis of high-end micro-precision proportional valves in the world is 15%, and domestic products are difficult to achieve this precision. Most of them adopt the method of adapting electromagnetic force and spring force, but the spring adaptation of small proportional valves is difficult, and the spring force needs to meet the nonlinear change characteristics of electromagnetic force, so that the adapted spring is mostly a special hole spring, which is difficult to process and has low reliability. SUMMARY

[0004] In view of the above problems, the purpose of the present application is to provide a proportional valve with reduced hysteresis and a design method thereof. By increasing the air gap length of the proportional valve, the high magnetic induction section of the air gap length is designed as a non-magnetic material, so as to ensure that the proportional valve works in the low magnetic induction strength interval in the working air gap. In this interval, the electromagnetic force curve is horizontal, and the force value is basically unchanged. It is easier to adapt to the required spring, so that the electromagnetic force and the spring force meet the balance requirement, thereby reducing the hysteresis of the proportional valve.

[0005] The technical scheme adopted by the present application is as follows: A proportional valve with reduced hysteresis, comprising a shell, one end of the shell is threadedly connected with an end cover, the other end of the shell is threadedly connected with a valve sleeve, a valve core assembly cooperating with the valve sleeve is movably arranged in the shell, a spring is arranged between the valve core assembly and the end cover, a coil assembly is arranged in the shell, a gas inlet nozzle abutting against the valve core assembly is fixedly installed in the valve sleeve, a guide cylinder assembly is arranged between the coil assembly and the valve core assembly, and a non-magnetic layer is arranged on the end face of the end cover close to the valve core assembly.

[0006] Preferably, the guide cylinder assembly comprises a magnetic isolation ring, one end of the magnetic isolation ring is provided with a lower magnetic ring, and the other end of the magnetic isolation ring is provided with an upper magnetic ring.

[0007] Preferably, the valve core assembly comprises a valve core movably extending into the guide cylinder assembly, a sealing pad base body is connected to one end of the valve core away from the spring, a sealing diaphragm assembly is clamped between the sealing pad base body and the valve core, and a sealing pad is connected to one end of the sealing pad base body away from the spring.

[0008] Preferably, the sealing diaphragm assembly comprises a sealing diaphragm, one side of the sealing diaphragm is provided with an upper pressing ring, and the other side of the sealing diaphragm is provided with a lower pressing ring.

[0009] A method for designing a proportional valve with reduced hysteresis, the method comprising the steps of: S1, designing a balance structure of a spool assembly, so that the spool assembly is only subjected to electromagnetic force and spring force during movement; S2, adding a guide cylinder assembly, and improving the levelness of the electromagnetic force curve through the action of a magnetic isolation ring, wherein the position of the magnetic isolation ring is obtained through parameterized simulation; S3, increasing the air gap length of the proportional valve, wherein the high magnetic induction section of the air gap length is designed to be a non-magnetic material, so as to ensure that the proportional valve works in a low magnetic induction strength interval in the working air gap.

[0010] Preferably, in the step S1, the balance structure of the spool assembly is designed according to the following formula: wherein D is the inner diameter of the air inlet nozzle, D1 is the inner diameter of the upper pressing ring or the lower pressing ring, and D2 is the outer diameter of the sealing gasket base or the spool clamping sealing diaphragm; the sizes of D, D1 and D2 are designed according to the above formula.

[0011] Preferably, in the step S3, a non-magnetic layer is arranged on the end face of the end cover.

[0012] As described above, due to the adoption of the above technical solutions, the present application has the following beneficial effects: By increasing the air gap length of the proportional valve, and designing the high magnetic induction section of the air gap length to be a non-magnetic material, the proportional valve is ensured to work in a low magnetic induction strength interval in the working air gap, the levelness of the electromagnetic force curve is good in this interval, and the force value is basically unchanged, so it is easier to adapt to the required spring, so that the electromagnetic force and the spring force meet the balance requirement, thereby reducing the hysteresis of the proportional valve. BRIEF DESCRIPTION OF DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope, and for those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0014] Figure 1 The overall cross-sectional structure schematic diagram provided for the embodiments of the present application; Figure 2 The guide cylinder assembly cross-sectional structure schematic diagram provided for the embodiments of the present application; Figure 3 A valve core assembly cross-sectional structure schematic diagram provided for the embodiment of the present application; Figure 4 A sealing diaphragm assembly cross-sectional structure schematic diagram provided for the embodiment of the present application; Figure 5 An end cover cross-sectional structure schematic diagram provided for the embodiment of the present application; Figure 6 A magnetic isolation ring parameter setting schematic diagram provided for the embodiment of the present application; Figure 7 A curve diagram of electromagnetic force change of different Δh when θ2=30° is provided for the embodiment of the present application; Figure 8 A schematic diagram of air gap magnetic induction intensity of different magnetic isolation ring positions is provided for the embodiment of the present application; Figure 9 A curve diagram of electromagnetic force change of different Δh when θ2=60° is provided for the embodiment of the present application; Figure 10 A curve diagram of electromagnetic force change of different Δh when θ2=90° is provided for the embodiment of the present application; Figure 11 A curve diagram of electromagnetic force change of different θ2 when Δh=0.2mm is provided for the embodiment of the present application; Figure 12 A curve diagram of electromagnetic force change of different θ1 when θ2=60° and Δh=0.2mm is provided for the embodiment of the present application; Figure 13 A curve diagram of electromagnetic force change of different h when θ2=60°, Δh=0.2mm and θ1=90° is provided for the embodiment of the present application; Figure 14 A curve diagram of electromagnetic force and adaptive spring force of different voltage is provided for the embodiment of the present application; Figure 15 A proportional valve flow characteristic curve diagram is provided for the embodiment of the present application; Figure 16 A curve diagram of air gap magnetic induction intensity change is provided for the embodiment of the present application; Figure 17 A curve diagram of air gap magnetic induction intensity change after structure optimization is provided for the embodiment of the present application; Figure 18 A curve diagram of electromagnetic force and adaptive spring force change after structure optimization is provided for the embodiment of the present application; Figure 19 A proportional valve flow characteristic curve diagram after structure optimization is provided for the embodiment of the present application.

[0015] Reference numerals in the attached drawings: 1-End cap; 101-Non-magnetic layer; 2-First sealing ring; 3-Coil assembly; 4-Outer shell; 5-Spring; 6-Guide cylinder assembly; 601-Lower magnetic ring; 602-Magnetic isolation ring; 603-Upper magnetic ring; 7-Valve core assembly; 701-Sealing gasket; 702-Sealing gasket substrate; 703-Valve core; 8-Sealing diaphragm assembly; 801-Upper pressure ring; 802-Sealing diaphragm; 803-Lower pressure ring; 9-Valve sleeve; 10-Second sealing ring; 11-Air inlet; 12-Third sealing ring; 13-Working chamber A; 14-Working chamber B; 15-Fourth sealing ring. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0017] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0018] In the description of this invention, it should be noted that if terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use, they are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0019] The following is combined Figures 1-19 The present invention will be described in detail below.

[0020] Example: A proportional valve for reducing hysteresis includes a housing 4, an end cap 1 threaded to one end of the housing 4, a valve sleeve 9 threaded to the other end of the housing 4, a valve core assembly 7 movably disposed in the housing 4 and cooperating with the valve sleeve 9, a spring 5 disposed between the valve core assembly 7 and the end cap 1, a coil assembly 3 disposed in the housing 4, an air inlet 11 fixedly installed in the valve sleeve 9 and abutting against the valve core assembly 7, a guide cylinder assembly 6 disposed between the coil assembly 3 and the valve core assembly 7, and a non-magnetic layer 101 disposed on the end face of the end cap 1 near the valve core assembly 7.

[0021] By increasing the air gap length of the proportional valve and designing the high magnetic induction section of the air gap with a non-magnetic material (i.e., the non-magnetic layer 101), the proportional valve can be ensured to operate in the low magnetic induction intensity range within the working air gap. In this range, the electromagnetic force curve has good horizontality and the force value remains basically unchanged. This makes it easier to adapt the spring 5 to meet the requirements, so that the electromagnetic force and the spring force can reach the balance requirement, thereby reducing the hysteresis of the proportional valve.

[0022] The guide cylinder assembly 6 includes a magnetic shielding ring 602, with a lower magnetic guide ring 601 at one end and an upper magnetic guide ring 603 at the other end. The magnetic shielding ring 602 is welded and fixed to the lower magnetic guide ring 601 and the upper magnetic guide ring 603.

[0023] The valve core assembly 7 includes a valve core 703 that extends movably into the guide cylinder assembly 6. A sealing gasket base 702 is connected to the end of the valve core 703 away from the spring 5. A sealing diaphragm assembly 8 is sandwiched between the sealing gasket base 702 and the valve core 703. A sealing gasket 701 is connected to the end of the sealing gasket base 702 away from the spring 5. The sealing gasket 701 is fixed to the sealing gasket base 702 by vulcanization bonding, and the sealing gasket base 702 and the valve core 703 are connected by an interference fit. The sealing gasket 701 ensures the sealing performance of the air inlet nozzle 11 end face.

[0024] The sealing diaphragm assembly 8 includes a sealing diaphragm 802. An upper pressure ring 801 is provided on one side of the sealing diaphragm 802, and a lower pressure ring 803 is provided on the other side. The sealing diaphragm 802 has an annular structure. It is fitted onto the protrusion of the sealing gasket base 702 and clamped by the sealing gasket base 702 and the valve core 703. The upper pressure ring 801 and the lower pressure ring 803 are then clamped by the valve sleeve 9 and the outer shell 4, thus achieving a fixed installation of the sealing diaphragm 802.

[0025] The coil assembly 3 has a first sealing ring 2 and a fourth sealing ring 15 on its two ends respectively. The first sealing ring 2 is mounted on the end cover 1 and the fourth sealing ring 15 is mounted on the outer shell 4. The valve sleeve 9 is fitted with a second sealing ring 10 on its outer side and the air inlet 11 is fitted with a third sealing ring 12 on its outer side.

[0026] When the proportional valve is not energized, the sealing gasket 701 of the valve core assembly 7 is tightly pressed against the air inlet 11 under the action of the spring 5, and the inlet and outlet are blocked. When the proportional valve is energized, as the control voltage increases, the electromagnetic force also increases. Since the electromagnetic force and the spring force are balanced, the valve core assembly 7 will slowly open the air inlet 11, thereby continuously increasing the output flow until it is fully open. When the control voltage decreases, the electromagnetic force also decreases, and the spring force that balances it also decreases and gradually resets. The valve core assembly 7 slowly closes under the action of the spring 5, thereby continuously reducing the output flow until it is fully closed.

[0027] A method for designing a proportional valve to reduce hysteresis, the method comprising the following steps: S1. Design a balanced structure for valve core assembly 7 so that valve core assembly 7 is only subjected to electromagnetic force and spring force during movement; S2. Add guide cylinder assembly 6 to improve the horizontality of the electromagnetic force curve through the action of magnetic shielding ring 602. The position of magnetic shielding ring 602 is obtained through parametric simulation. S3. Increase the air gap length of the proportional valve. The high magnetic induction section of the air gap is designed with a non-magnetic material to ensure the proportional valve operates within a low magnetic induction intensity range in the working air gap. In step S3, a non-magnetic layer 101 is provided on the end face of the end cap 1 to remove the area with high magnetic induction intensity in the air gap section.

[0028] In step S1, the balance structure of valve core assembly 7 is designed according to the following formula: Where D is the inner diameter of the air inlet 11, D1 is the inner diameter of the upper pressure ring 801 or the lower pressure ring 803, and D2 is the outer diameter of the sealing gasket base 702 or the valve core 703 where the sealing diaphragm 802 is clamped; the sizes of D, D1 and D2 are designed according to the above formula.

[0029] The above formula references the document "Calculation and Influencing Factor Analysis of Effective Diameter of Pressure Reducing Valve Diaphragm Element Based on Finite Element Method". Its principle is as follows: the sealing diaphragm 802 divides the proportional valve's inlet into working chamber A13 and working chamber B14. Working chambers A13 and B14 are connected through the central hole of the valve core assembly 7. The valve core assembly 7, the outer shell 4, and the guide cylinder assembly 6 are clearance-fitted to ensure equal pressure in working chambers A13 and B14. It is only necessary to ensure that the effective area S of the sealing diaphragm 802 and the inlet area are equal. Equal forces ensure that the valve core assembly 7 is in a balanced state.

[0030] In step S2, the proportional valve of this application will be used as an example for explanation: The parameter settings for the magnetic shielding ring 602 are as follows: Figure 6 As shown, the initial position of the magnetic isolation ring 602 is ABCD. The angle between AD and the vertical direction is θ1, and the angle between BC and the vertical direction is θ2. AB is the length h of the magnetic isolation ring 602. The magnetic isolation ring 602 moves vertically to a new position A'B'C'D', with a moving distance of Δh, where upward is positive and downward is negative. At the initial position B, it is flush with the valve core 703 before it is engaged. AB=CD=h=1mm, θ1=θ2=90°, and Δh=0mm.

[0031] a) Electromagnetic force changes at different Δh values ​​when θ2=30° With θ2 = 30° and Δh values ​​of 0 mm, 0.2 mm, 0.4 mm, -0.2 mm, and -0.4 mm respectively, and the remaining parameters being the initial values, the electromagnetic force-displacement curve is obtained as follows: Figure 7 As shown. From Figure 7 The simulation results show that when θ2 = 30°, the electromagnetic force of the electromagnet gradually decreases as the position of the magnetic shielding ring 602 moves upward. This is because the magnetic induction intensity at the working air gap decreases as the position of the magnetic shielding ring 602 moves upward (e.g., ...). Figure 8 As shown). But the levelness ( It's getting better and better, at Δh=0.2mm ( ) and Δh=0.4mm ( The horizontal level is close at Δh=0.2mm, but the electromagnetic force is greater at Δh=0.2mm, so the position of Δh=0.2mm is preferred.

[0032] b) Electromagnetic force changes at different Δh values ​​when θ2 = 60° With θ2 = 60° and Δh values ​​of 0 mm, 0.2 mm, 0.4 mm, -0.2 mm, and -0.4 mm respectively, and the remaining parameters being the initial values, the electromagnetic force-displacement curve is obtained as follows: Figure 9 As shown. From Figure 9 The simulation results show that when θ2=60°, the electromagnetic force of the electromagnet gradually decreases as the position of the magnetic isolation ring 602 moves upward. This is because the magnetic induction intensity at the working air gap decreases as the position of the magnetic isolation ring 602 moves upward. However, the levelness improves, and the levelness is basically the same at Δh=0.2mm and Δh=0.4mm, but the electromagnetic force is greater at Δh=0.2mm. Therefore, the position Δh=0.2mm is preferred.

[0033] C) Electromagnetic force changes at different Δh values ​​when θ2 = 90° With θ2 = 90° and Δh values ​​of 0 mm, 0.2 mm, 0.4 mm, -0.2 mm, and -0.4 mm respectively, and the remaining parameters being the initial values, the electromagnetic force-displacement curve is obtained as follows: Figure 10 As shown. From Figure 10 The simulation results show that when θ2=90°, the electromagnetic force of the electromagnet gradually decreases as the position of the magnetic isolation ring 602 moves upward. This is because the magnetic induction intensity at the working air gap decreases as the position of the magnetic isolation ring 602 moves upward. However, the levelness improves, and the levelness is basically the same at Δh=0.2mm and Δh=0.4mm, but the electromagnetic force is greater at Δh=0.2mm. Therefore, the position Δh=0.2mm is preferred.

[0034] d) Changes in electromagnetic force at different θ2 values ​​for Δh=0.2mm Simulations using a), b), and c) revealed that, regardless of the different values ​​of θ2, the electromagnetic force-displacement curves at Δh = 0.2 mm all exhibited good horizontal characteristics. Comparisons showed that... Figure 11 The simulation results. From Figure 11 The simulation results show that when Δh=0.2mm, the electromagnetic force of the electromagnet decreases as θ2 increases, and the levelness of the electromagnetic force-displacement curve is best when θ2=60°. Therefore, the parameters of the magnetic isolation ring 602 are selected as θ2=60° and Δh=0.2mm.

[0035] e) Electromagnetic force variation at different θ1 values: θ2 = 60°, Δh = 0.2mm Based on d), the preferred parameters for the magnetic shielding ring 602 are determined to be θ2 = 60° and Δh = 0.2 mm. When θ1 = 30°, θ1 = 60°, and θ1 = 90°, the remaining parameters are the initial values. The electromagnetic force variation curve is shown below. Figure 12 As shown. From Figure 12 The simulation results show that when θ2 = 60° and Δh = 0.2 mm, the electromagnetic force-displacement curves almost coincide when θ1 = 30°, θ1 = 60°, and θ1 = 90°. Therefore, θ1 has little effect on the magnitude and levelness of the electromagnetic force. Considering the ease of processing, θ1 = 90° is chosen.

[0036] f) Electromagnetic force variation curves with θ2=60° and Δh=0.2mm at different h values. Based on the simulations in the previous sections, the parameters of the 602 magnetic shielding ring are determined to be θ2=60°, Δh=0.2mm, and θ1=90°. The electromagnetic force variation curves when h=1mm, h=1.5mm, h=2mm, and h=2.5mm are shown below. Figure 13 As shown. From Figure 13 The simulation results show that when θ2=60°, Δh=0.2mm, and θ1=90°, the levelness of the electromagnetic force remains basically unchanged, but the force value decreases as h increases. Therefore, h=1mm is chosen.

[0037] Through the above parametric simulation, the parameters of the magnetic shielding ring 602 were finally determined as θ2=60°, Δh=0.2mm, θ1=90°, and h=1mm.

[0038] In step S3, the electromagnetic force curve is relatively flat in this range (low magnetic induction intensity range), and the force value remains basically unchanged. This makes it easier to adapt a spring that meets the requirements, so that the electromagnetic force and the spring force can reach the balance requirement, thereby reducing the hysteresis of the proportional valve.

[0039] Specifically: Through the simulation operation in step S2, it can be seen that adding the magnetic isolation ring 602 can improve the levelness of the electromagnetic force curve. However, due to the change in the air gap magnetic induction intensity during the movement of the valve core 703, the electromagnetic force increases sharply with the increase of the displacement of the valve core 703 (high magnetic induction segment). In actual design, this stage needs to be removed (designed as a non-magnetic material) to ensure that the proportional valve in the working air gap works in the low magnetic induction intensity range. In this range, the levelness of the electromagnetic force curve is good and the force value remains basically unchanged.

[0040] Taking the proportional valve of this application as an example: Because electromagnets inherently possess hysteresis, and are potentially affected by spring force and friction during the operation of proportional valves, the relationship between control current and output flow rate is not linear. The same input current will result in different output flow rates during the opening and closing of the proportional valve; that is, the output flow rate of the proportional valve exhibits hysteresis. The calculation formula is as follows: Where H represents hysteresis, This represents the maximum value of the output flow difference corresponding to the increase or decrease of the electrical signal. This represents the maximum output flow rate.

[0041] Without adding non-magnetic materials in the high magnetic induction stage, the electromagnetic force curves under different voltages and the adaptive spring force curves are obtained as follows: Figure 14 As shown. From Figure 14 The curves of electromagnetic force and spring force under different voltages show that the electromagnetic force increases sharply after the stroke of valve core 703 exceeds 0.2mm. In the later curve segments, the spring force cannot cover the maximum electromagnetic force value. This will cause the proportional valve in the actual product to only achieve force balance in a certain range. Beyond this range, the electromagnetic force and spring force will no longer be balanced, resulting in a deterioration of the proportional valve's proportional characteristics and an increase in flow hysteresis.

[0042] Without adding non-magnetic materials during the high magnetic induction stage, the flow characteristic curve of the proportional valve obtained from the experiment is as follows: Figure 15 As shown. From Figure 15 The test results show that as the control current increases, the flow rate of the proportional valve gradually increases, with a maximum flow rate of 107 L / min. As the control current decreases, the flow rate of the proportional valve gradually decreases. However, during the opening and closing process, the output flow rate curves do not coincide. The maximum flow rate difference is 64.8 L / min when the control current is 0.27 A. The flow rate hysteresis of the proportional valve can be calculated to be 60.6% using the proportional valve flow rate hysteresis formula.

[0043] Cause analysis: From Figure 15The proportional valve test results show that the flow curve has a long horizontal segment when the proportional valve is closed. This means that valve core 703 remains stationary during this phase, and the flow rate is consistently at its maximum. This results in a larger difference in output flow rate, causing greater flow hysteresis in the proportional valve. Since the proportional valve is mainly acted upon by electromagnetic force and spring force during operation, the fact that valve core 703 remains stationary when closed indicates that the electromagnetic force is greater than the spring force at this point. This can be verified using the formulas for electromagnetic force and magnetic induction intensity. Once the proportional valve is designed, the magnetic pole surface area S remains unchanged, and the air permeability... Therefore, the magnitude of the electromagnetic force is mainly determined by the magnetic induction intensity B, so the magnetic induction intensity must be reduced in the attracted state.

[0044] The change in magnetic induction intensity at the working air gap during the movement of the proportional valve core 703 is as follows: Figure 16 As shown. From Figure 16 The simulation results show that as the displacement of valve core 703 increases, the air gap magnetic induction intensity also increases. When the displacement of valve core 703 is greater than 0.2 mm, the air gap magnetic induction intensity increases rapidly. Figure 14 The electromagnetic force variation curve shows that the electromagnetic force increases rapidly after the displacement of valve core 703 exceeds 0.2 mm.

[0045] Structural optimization: As can be seen from the simulation results above, when the valve core 703 travels beyond a certain position, the magnetic induction intensity will increase rapidly, causing the electromagnetic force to increase rapidly. When the proportional valve is closed, the electromagnetic force in this travel segment will remain at a large value for a long time, preventing the valve core 703 from resetting, thus causing the proportional valve flow to stagnate and increase. Therefore, this travel segment must be removed when optimizing the proportional valve structure.

[0046] Therefore, the structural optimization scheme for the proportional valve is to increase the actual air gap length, remove the stage with high magnetic induction intensity, ensure that the 0.26mm working stroke of the proportional valve is in the stage with low magnetic induction intensity, reduce the electromagnetic force during the closing stage of the proportional valve, and reduce the holding time at the maximum position of the valve core 703, thereby reducing the flow hysteresis of the proportional valve.

[0047] In this application, the actual air gap length of the proportional valve is increased to 0.36 mm. The curve showing the change in air gap magnetic induction intensity with valve core 703 displacement during this stroke range is as follows. Figure 17 As shown. From Figure 17 The simulation results show that the magnetic induction intensity does not change much within the 0.26mm working stroke range of the proportional valve, thus ensuring that the electromagnetic force of the proportional valve does not change significantly during the working stroke range.

[0048] The curves showing the changes in electromagnetic force and adapting spring force after structural optimization are as follows: Figure 18 As shown. From Figure 18The curves showing the changes in electromagnetic force and spring force under different voltages show that the spring force is completely enveloped within the family of electromagnetic force curves. This allows for the adaptation of a spring that satisfies the changes in electromagnetic force, ensuring that the electromagnetic force and spring force remain balanced throughout the entire working stroke, thereby reducing the hysteresis of the proportional valve.

[0049] The optimized proportional valve flow rate change curve was tested as follows: Figure 19 As shown. From Figure 19 The flow test results show that the maximum flow holding time during the closing phase of the optimized proportional valve is significantly shortened. The maximum flow rate is 107 L / min, and the maximum flow rate difference is 15.4 L / min when the control current is 0.34 A. The flow hysteresis is calculated to be 14.4% using the flow hysteresis formula, which shows a significant reduction in flow hysteresis.

[0050] Advantages of this application: (1) A pressure-balanced valve core assembly 7 was designed so that the valve core assembly 7 is not affected by hydraulic pressure during the movement. In this way, the electromagnetic force and the spring force can be easily balanced, which facilitates continuous control of the output flow. (2) A guide cylinder assembly 6 with a magnetic shielding ring 602 was designed. By optimizing the position and size of the magnetic shielding ring 602, the horizontality of the electromagnetic force curve was improved. (3) An end cap 1 with a non-magnetic layer 101 was designed to remove the stage with a large magnetic induction intensity in the air gap section. This makes it easier to ensure that the spring force falls completely within the electromagnetic force curve family when the working air gap is in the stage with a small magnetic induction intensity (horizontal section of the electromagnetic force curve). This reduces the difficulty of adapting the spring 5, and makes it easier to achieve a balance between electromagnetic force and spring force, thereby reducing the flow hysteresis of the proportional valve.

[0051] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A proportional valve for reducing hysteresis, comprising a housing (4), one end of which is threadedly connected to an end cap (1), and the other end of which is threadedly connected to a valve sleeve (9), a valve core assembly (7) movably disposed within the housing (4) and cooperating with the valve sleeve (9), a spring (5) disposed between the valve core assembly (7) and the end cap (1), a coil assembly (3) disposed within the housing (4), and an air inlet (11) fixedly installed within the valve sleeve (9) and abutting against the valve core assembly (7), characterized in that, A guide tube assembly (6) is provided between the coil assembly (3) and the valve core assembly (7), and a non-magnetic layer (101) is provided on the end face of the end cap (1) near the valve core assembly (7).

2. A proportional valve for reducing hysteresis according to claim 1, characterized in that, The guide cylinder assembly (6) includes a magnetic shielding ring (602), with a lower magnetic guide ring (601) at one end of the magnetic shielding ring (602) and an upper magnetic guide ring (603) at the other end of the magnetic shielding ring (602).

3. A proportional valve for reducing hysteresis according to claim 1, characterized in that, The valve core assembly (7) includes a valve core (703) that extends movably into the guide cylinder assembly (6). A sealing gasket base (702) is connected to one end of the valve core (703) away from the spring (5). A sealing diaphragm assembly (8) is sandwiched between the sealing gasket base (702) and the valve core (703). A sealing gasket (701) is connected to one end of the sealing gasket base (702) away from the spring (5).

4. A proportional valve for reducing hysteresis according to claim 3, characterized in that, The sealing diaphragm assembly (8) includes a sealing diaphragm (802), an upper pressure ring (801) is provided on one side of the sealing diaphragm (802), and a lower pressure ring (803) is provided on the other side of the sealing diaphragm (802).

5. A proportional valve design method for reducing hysteresis, characterized in that, The design method for the proportional valve according to any one of claims 1-4 includes the following steps: S1. Design a balanced structure for the valve core assembly (7) so that the valve core assembly (7) is only subjected to electromagnetic force and spring force during the movement. S2. Add a guide cylinder assembly (6) to improve the levelness of the electromagnetic force curve through the action of the magnetic shielding ring (602). The position of the magnetic shielding ring (602) is obtained through parametric simulation. S3. Increase the air gap length of the proportional valve. In the high magnetic induction section of the air gap, the material is designed to be non-magnetic to ensure that the proportional valve operates in the low magnetic induction intensity range within the working air gap.

6. The proportional valve design method for reducing hysteresis according to claim 5, characterized in that, In step S1, the balance structure of the valve core assembly (7) is designed according to the following formula: Wherein, D is the inner diameter of the air inlet (11), D1 is the inner diameter of the upper pressure ring (801) or the lower pressure ring (803), and D2 is the outer diameter of the sealing gasket base (702) or the valve core (703) where the sealing diaphragm (802) is clamped; the sizes of D, D1 and D2 are designed according to the above formula.

7. The proportional valve design method for reducing hysteresis according to claim 5, characterized in that, In step S3, a non-magnetic layer (101) is provided on the end face of the end cap (1).

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