Proportional solenoid and electromagnetic valve with position detection

Abstract

The application discloses a proportional electromagnet with position detection and a solenoid valve, and aims to solve the technical problem that the proportional electromagnet is enlarged in size when the armature position is detected. The proportional electromagnet comprises a magnetic material sleeve, an excitation coil arranged in the magnetic material sleeve and provided with a support framework, a fixed iron core coaxially arranged and fixed in the magnetic material sleeve, an armature movably arranged in the magnetic material sleeve and used for moving along the magnetic material sleeve in the axial direction, and a pipe cap used for limiting the position of the armature. A TMR sensor used for detecting the position of the armature is arranged in the pipe cap. The proportional electromagnet has the advantages of small size and high detection precision, and the solenoid valve composed of the proportional electromagnet has the characteristics of high control precision and reliability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electromagnet, in particular to a proportional electromagnet with position detection and electromagnetic valve. BACKGROUND

[0002] The proportional electromagnet is a stroke type electromagnet, which can generate an electromagnetic force or displacement proportional to the current. It works on the principle of electromagnetism, usually composed of three parts: winding, core and power supply. The winding is a coil made of wire, wound around the core. When the current passes through the winding, according to Ampere's law, a magnetic field is generated, and the magnetic field strength is proportional to the size of the current. The core enhances the strength of the magnetic field, usually made of soft magnetic material with high magnetic permeability, which can effectively concentrate and enhance the magnetic field. The power supply (DC power supply or AC power supply, depending on the application requirements) provides current to the winding, thereby generating a magnetic field. The magnetic force of the proportional electromagnet is proportional to the control signal, thereby achieving precise proportional control. By adjusting the size and voltage value of the control signal, the suction size and action direction of the proportional electromagnet can be accurately controlled. Therefore, the proportional electromagnet is widely used in the fields of automobile industry, industrial automation, aerospace industry, medical industry, etc.

[0003] In addition, the proportional electromagnet is also a key component commonly used in hydraulic control systems, which can realize precise control of the hydraulic system in cooperation with the hydraulic valve. However, with the continuous improvement of functional safety requirements of the hydraulic system, it is necessary to accurately detect the position of the core, i.e. the armature, in the proportional electromagnet.

[0004] The proportional electromagnet core position detection method known to the inventor includes using LVDT linear position sensor for position detection and using Hall sensor for position detection. However, in the process of implementing the technical solutions in the embodiments of the present application, the inventor found that when using the LVDT linear displacement sensor to detect the position of the armature, it needs to be lengthened along the axial direction of the armature, thereby increasing the axial length of the proportional electromagnet, affecting its installation applicability, and some proportional electromagnetic valves are limited by their structure and cannot be installed in the axial direction. LVDT. When using a Hall sensor to detect the position of the armature, a magnet needs to be installed at the end of the armature axis to achieve detection, which also increases the axial length of the armature and the volume of the proportional electromagnet, and increases the number of accessories and assembly difficulty.

[0005] The information disclosed in this BACKGROUND section is only for the purpose of enriching the understanding of the background of the present disclosure and should not be considered as acknowledging or implying in any form that this information constitutes prior art known to those skilled in the art. SUMMARY

[0006] The present disclosure provides a proportional electromagnet with position detection and a solenoid valve, aiming to solve the technical problem that the proportional electromagnet volume increases when the armature position detection is realized.

[0007] According to one aspect of the present disclosure, a proportional electromagnet with position detection is provided, which comprises a magnetic material sleeve, an excitation coil provided with a support framework in the magnetic material sleeve, a fixed iron core coaxially arranged in the magnetic material sleeve and fixed relative to the magnetic material sleeve, an armature movably embedded in the magnetic material sleeve and used for axial movement along the magnetic material sleeve, and a pipe cap used for limiting the position of the armature; a TMR sensor for detecting the position of the armature is embedded in the pipe cap.

[0008] In some embodiments of the present disclosure, a blind hole is formed in the end face of the pipe cap along the magnetic material sleeve, and the TMR sensor is correspondingly embedded in the blind hole.

[0009] In some embodiments of the present disclosure, the diameter of the armature is R, and the vertical distance of the TMR sensor from the central axis of the magnetic material sleeve is ΔZ, then ΔZ / R<81%.

[0010] In some embodiments of the present disclosure, R-ΔZ≥2mm.

[0011] In some embodiments of the present disclosure, a through hole is provided in the center of the pipe cap for installing a corresponding manual push rod, and ΔZ≥2mm.

[0012] In some embodiments of the present disclosure, the intersection of the end face of the magnetic material sleeve close to the pipe cap and the central axis of the magnetic material sleeve is the origin, and the vertical distance of the TMR sensor from the plane where the origin is located along the axial direction of the magnetic material sleeve is ΔY, then ΔY≥2mm.

[0013] In some embodiments of the present disclosure, ΔY<2R.

[0014] In some embodiments of the present disclosure, the TMR sensor comprises a first terminal, a second terminal, a third terminal, and a fourth terminal, and the first terminal and the second terminal, the second terminal and the third terminal, the third terminal and the fourth terminal, and the fourth terminal and the first terminal correspond to a magnetoresistance effect detection element in series, respectively, for generating a change in its own resistance value with the size of the external magnetic field.

[0015] In some embodiments of the present disclosure, the proportional electromagnet further comprises a permanent magnet arranged beside the magnetoresistance effect detection element of the TMR sensor for applying a magnetic field to the magnetoresistance effect detection element.

[0016] According to another aspect of the present disclosure, a solenoid valve is provided, which contains the above-mentioned proportional electromagnet.

[0017] The one or more technical solutions provided in the embodiments of the present application have at least any of the following technical effects or advantages: the detection of the position of the armature of the proportional electromagnet is realized by the TMR sensor embedded in the pipe cap, which can avoid the problem of the increase in the volume of the proportional electromagnet caused by the extension or the addition of magnets along the axial direction of the armature in the prior art, thereby ensuring the miniaturization of the proportional electromagnet; on the other hand, the electromagnet is easy to assemble, and the maintenance and replacement of parts are convenient during use; further, based on the boundary conditions identified by the long-term practical research experience of the inventor, the reasonable limitation of the relative installation position of the TMR sensor ensures a wide signal output range of the TMR sensor, and the detection accuracy and reliability of the proportional electromagnet for the position of the armature are effectively improved. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 FIG. 1 is a sectional structure schematic diagram of a proportional electromagnet with position detection in an embodiment of the present application.

[0019] Figure 2 FIG. 3 is a labeled schematic diagram of a proportional electromagnet in an embodiment of the present application.

[0020] Figure 3 FIG. 4 is a related curve diagram of the electromagnetic force of a proportional electromagnet in an embodiment of the present application.

[0021] Figure 4 FIG. 5 is a related curve diagram of the magnetic induction intensity of a proportional electromagnet in an embodiment of the present application.

[0022] Figure 5 FIG. 6 is an output signal curve diagram of a TMR sensor of a proportional electromagnet in an embodiment of the present application.

[0023] Figure 6 FIG. 7 is a partial structure schematic diagram of a TMR sensor in an embodiment of the present application.

[0024] Figure 7 FIG. 8 is a TMR sensor output range data table of a proportional electromagnet in an embodiment of the present application.

[0025] In the above figures, 1 is a sleeve of magnetic material, 2 is an excitation coil, 3 is a support framework, 41 is a fixed core, 42 is a magnetic shield ring, 5 is an armature, 6 is a pipe cap, 7 is a TMR sensor, 71 is a fixed layer, 72 is a middle layer, 73 is a free layer, 8 is a manual push rod, and 9 is a permanent magnet. DETAILED DESCRIPTION

[0026] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inner", "outer", "vertical", "horizontal", "clockwise", "counterclockwise" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0027] The programs involved or relied on in the following embodiments are all conventional programs or simple programs in the technical field, and those skilled in the art can make conventional choices or adaptive adjustments according to specific application scenarios. In order to better understand the technical solutions of the present application, the above technical solutions will be described in detail in combination with the drawings and specific embodiments of the specification.

[0028] To solve the technical problem that the existing proportional electromagnet will increase in volume or increase in the number of parts when detecting the position of the armature through the LVDT linear displacement sensor or the Hall sensor. The present example discloses a proportional electromagnet with position detection, referring to Figure 1 which includes a magnetic material sleeve 1, an excitation coil 2 and a support skeleton 3. The magnetic material sleeve 1 is a cylindrical structure composed of soft magnetic material with a certain wall thickness, and the excitation coil 2 is enclosed in the cylinder wall. The excitation coil 2 is wound by metal wire (such as copper wire, etc.), and the two ends of the coil are stretched out from the cylinder wall of the magnetic material sleeve to connect the power supply. When the excitation coil 2 is energized, it will generate an electromagnetic field and produce an electromagnetic force on the armature 5, and the action of the proportional electromagnet is realized through this electromagnetic force. In this embodiment, the magnetic material sleeve 1 used to enclose the excitation coil 2 is made of soft magnetic material, thereby realizing the guidance and concentration of the magnetic field through the magnetic material sleeve 1, avoiding magnetic leakage, and acting as a shielding element for external magnetic fields. Considering that the excitation coil 2 is thin and soft when winding, it is not easy to shape and is prone to deformation after winding due to external force, therefore, in this embodiment, the excitation coil 2 is wound on the support skeleton 3, which not only realizes the supporting effect of the excitation coil 2, but also avoids the deformation of the excitation coil 2 caused by external force interference.

[0029] To realize the action of the proportional electromagnet as needed, referring to Figure 1, a magnetic core tube is coaxially arranged in the hollow magnetic material sleeve 1 to respond to the magnetic field generated by the excitation coil 2, so as to realize the action of the electromagnet. Specifically, the magnetic core tube includes a fixed core 41, a magnetic shield ring 42, a guide sleeve 43, an armature 5, and a pipe cap 6. Among them, the fixed core 41 is arranged in the magnetic material sleeve 1 and is relatively fixed, which can concentrate the magnetic field in the inside of the excitation coil, increase the magnetic flux, and then achieve the purpose of strengthening the magnetic field strength. One end of the fixed core 41 is connected with the guide sleeve 43 through the magnetic shield ring 42, so as to realize the coaxial arrangement of the armature 5 in the excitation coil through the guide sleeve 43. In this embodiment, the fixed core 41 is a cylindrical structure with an outer contour matching the inner contour of the magnetic material sleeve, the guide sleeve 43 is coaxially arranged with the fixed core 41, and the outer contour of the guide sleeve 43 is consistent with the outer contour of the fixed core 41; the armature 5 is movably embedded in the guide sleeve 43, and one end of the armature 5 is provided with a guide rod arranged at the center axis position of the fixed core 41, which serves as the action end of the electromagnet. When the excitation coil 2 is energized to generate a magnetic field, the armature 5 is magnetized accordingly, so as to generate electromagnetic attraction between the armature 5 and the fixed core, thereby realizing the action of the armature 5, and therefore the length of the guide sleeve 43 in this example is greater than the designed movement distance of the armature 5. In addition, in order to prevent the armature 5 from falling off from the end of the guide sleeve 43, referring to Figure 1 , the pipe cap 6 is arranged at the end of the guide sleeve 43. In this embodiment, the guide sleeve 43 is threadedly connected with the pipe cap 6, and a sealing ring is embedded between the pipe cap and the inner wall of the guide sleeve to achieve good sealing effect. In addition, in some other embodiments, a through hole is arranged in the inside of the armature 5 to facilitate the passage of hydraulic oil or lubricating oil when hydraulic control is realized.

[0030] In order to realize the accurate detection of the action position of the armature in the proportional electromagnet, referring to Figure 1 , a TMR sensor 7 is embedded at the pipe cap in this embodiment. Specifically, in this embodiment, a blind hole is formed on the end surface of the pipe cap 6 along the axial direction of the magnetic core tube, i.e. the movement direction of the armature, and the TMR sensor is embedded in the blind hole and then the blind hole is plugged.

[0031] Specifically, in this embodiment, referring to Figure 2 , the diameter of the armature is R, and the vertical distance between the TMR sensor and the center axis of the magnetic material sleeve is ΔZ; the inventors found during the implementation of this embodiment that when ΔZ / R<81%, the signal strength of the TMR sensor can be effectively ensured; further, in this embodiment, considering that the TMR sensor is embedded in the blind hole formed in the pipe cap 6, R-ΔZ≥2mm is defined to ensure the integrity of the blind hole wall, so as to facilitate the installation of the pipe cap and effectively protect the TMR sensor. In addition, in this embodiment, in order to avoid the manual reset of the armature 5 when the proportional electromagnet is powered off and other problems, referring to Figure 1, the through hole is provided at the center of the pipe cap 6 along the movement direction of the armature, and the manual push rod 8 is movably embedded in the through hole. Thus, the proportional electromagnet is actuated by manually pushing the manual push rod 8. In order to ensure that the manual push rod 8 has sufficient and reliable installation space at the pipe cap 6, in the embodiment, ΔZ≥2mm, thereby avoiding problems such as exposure of the TMR sensor and contact interference with the manual push rod. In addition, referring to Figure 2 , the intersection of the end surface of the magnetic material sleeve close to the pipe cap and the central axis of the magnetic material sleeve is taken as the origin, the vertical distance of the TMR sensor from the plane where the origin is located along the axial direction of the magnetic material sleeve is taken as ΔY, and ΔY≥2mm is ensured, thereby ensuring the structural strength of the pipe cap, so as to avoid damage to the TMR sensor embedded therein due to external force interference. In the embodiment, ΔY<2R, thereby avoiding that the proportional solenoid valve is too long, which limits the use scenario, and thus the proportional solenoid valve is miniaturized.

[0032] Referring to Figure 2 , in the embodiment, the air gap GAP between the end surface of the armature 5 close to the fixed core 41 and the fixed core 41 is taken as the independent variable, and referring to Figure 3 , a relationship curve between the air gap GAP and the electromagnetic force of the proportional electromagnet is obtained. In the embodiment, the diameter of the armature 5 is 22mm. As can be seen from the relationship curve between the air gap GAP and the electromagnetic force, when the air gap GAP between the armature 5 and the fixed core 41 is 2-5mm, the electromagnetic force of the proportional electromagnet is basically constant, which can meet the proportional control requirement of the proportional solenoid valve. Thus, the proportional solenoid valve with the armature diameter of 22mm is taken as an example for description.

[0033] Specifically, in the embodiment, the diameter of the armature of the proportional electromagnet is 22mm, the installation position of the TMR sensor at the pipe cap satisfies ΔY=12mm and ΔZ=6mm, the relationship experiment between the air gap GAP and the magnetic induction intensity of the electromagnet is carried out based on the proportional electromagnet, and the experimental results are shown in Figure 4 . Thus, it can be seen that the magnetic induction intensity mainly appears in the Y and Z components, and the X component can be ignored. Thus, in the embodiment, a comparative experiment is carried out between the TMR sensor and the Hall sensor used in the prior art, and the experimental results are shown in Figure 5 . Figure 5 The proportional electromagnet air gap GAP and the relationship curve between the TMR sensor signal and the Hall sensor signal are shown in the figure. The driving voltage of the TMR sensor and the Hall sensor is 1V. In the figure, the Hall curve represents the Hall sensor signal, and the MRsensor curve represents the TMR sensor signal. As can be seen from Figure 5It can be seen that when the air gap GAP changes from 2mm to 5mm, the signal change of the Hall sensor is only 0.6mV, while the signal change of the TMR sensor is 40.6mV, that is, under the same air gap change, the signal change of the TMR sensor is much larger than that of the Hall sensor, and the larger signal change can effectively increase the stability of the signal and prevent false detection caused by external disturbance, thereby enabling the TMR sensor to achieve high-precision detection of the armature displacement.

[0034] To achieve accurate detection output of the TMR sensor, in the embodiment, the TMR sensor includes a first terminal V, a second terminal V1, a third terminal G, and a fourth terminal V2, wherein the first terminal V and the second terminal V1, the second terminal V1 and the third terminal G, the third terminal G and the fourth terminal V2, and the fourth terminal V2 and the first terminal V are respectively connected in series with a magnetoresistance effect detection element, which can generate a change in its own resistance value with the change in the size of the external magnetic field. In this example, the TMR detection element is connected in series to form a Wheatstone bridge, and in other embodiments, the TMR detection element is connected in parallel to form a Wheatstone bridge.

[0035] Referring to Figure 6 , the TMR detection element includes a free layer 73, an intermediate layer 72, and a fixed layer 71. The magnetization direction of the fixed layer does not change with the change in the external magnetic field, and the magnetization direction of the free layer changes with the change in the external magnetic field. When the included angle between the magnetization directions of the free layer and the fixed layer changes, the resistance value of the TMR detection element will change accordingly. In order to change the magnetization direction of the free layer, in this example, the X-direction component and the Y-direction component of the external magnetic field need to change at the same time, and Figure 4 The results show that the X-direction component is basically zero, that is, it does not change, and only the Y-direction component changes. If a common TMR detection element is used, the magnetization direction of the free layer is always parallel to the Y-direction. In this case, when the Y-direction magnetic field changes, the magnetization direction of the free layer always remains in the Y-direction, that is, the included angle between the magnetization directions of the free layer and the fixed layer does not change, resulting in no change in the signal output of the TMR, that is, it cannot detect the position of the armature. Therefore, in this embodiment, referring to Figure 6 , a permanent magnet 9 is built-in in the +X direction and the -X direction of the TMR detection element. The permanent magnet 9 generates a built-in magnetic field along the X direction in the TMR detection element. The generation of the built-in magnetic field makes the magnetization direction of the free layer not parallel to the Y direction, and the magnetization direction of the free layer changes with the change in the size of the Y-direction magnetic field component, thereby achieving the function of detecting the position of the armature.

[0036] In this example, a large number of experimental studies on the TMR signal output range under different combinations of ΔY and ΔZ values are carried out, and the results are shown in Figure 7, the combination of different numerical values of ΔY and ΔZ in the figure corresponds to the signal range output by the TMR sensor when the air gap of the armature varies in the range of 2mm to 5mm. It is found from practical experience combined with the data in the figure that when ΔZ / R<81%, the output range of the TMR sensor is not less than 20mV, thereby ensuring the strength of the sensor signal and ensuring the detection accuracy.

[0037] In addition, the example also discloses an electromagnetic valve comprising the proportional electromagnet, which comprises the proportional electromagnet and a hydraulic valve, the hydraulic valve is coaxially fixedly connected with the magnetic core tube of the proportional electromagnet, and the valve core in the hydraulic valve is coaxially drivingly connected with the armature of the proportional electromagnet, so that the armature is controlled to act corresponding to the energization of the excitation coil, thereby driving the hydraulic valve core to act, realizing the conduction of the corresponding degree, and the position of the armature is accurately detected by the TMR sensor at the pipe cap of the proportional electromagnet, so as to determine the position of the hydraulic valve core, and realize the accurate control of the electromagnetic valve.

[0038] Although some preferred embodiments of the present application have been described, those skilled in the art can make additional changes and modifications to these embodiments once they know the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0039] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalent technologies, the present application also intends to include these modifications and variations.

Claims

1. A proportional solenoid with position detection, characterized by, The application relates to a magnetic material sleeve, a magnetic exciting coil provided with a supporting framework in the magnetic material sleeve, a fixed iron core coaxially arranged in the magnetic material sleeve and fixed relative to the magnetic material sleeve, a movable armature movably arranged in the magnetic material sleeve and used for axial movement along the magnetic material sleeve, and a pipe cap used for limiting the position of the armature; a blind hole is arranged at a non-central position of the end surface of the pipe cap and axially extends along the magnetic material sleeve, and a TMR sensor for detecting the position of the armature is embedded in the blind hole; the TMR sensor comprises a magnetoresistance effect detecting element and a permanent magnet arranged beside the magnetoresistance effect detecting element and used for applying a magnetic field to the magnetoresistance effect detecting element; the diameter of the armature is R, the vertical distance between the TMR sensor and the central axis of the magnetic material sleeve is Delta Z, and Delta Z / R is less than 81%; and R-Delta Z is greater than or equal to 2 mm.

2. The proportional electromagnet according to claim 1, characterized in that A through hole for arranging a corresponding manual push rod is arranged at the center of the pipe cap, and Delta Z is greater than or equal to 2 mm.

3. The proportional electromagnet according to claim 2, characterized in that The intersection between the end surface of the magnetic material sleeve close to the pipe cap and the central axis of the magnetic material sleeve is the original point, the vertical distance between the TMR sensor and the plane where the original point is located along the axial direction of the magnetic material sleeve is Delta Y, and Delta Y is greater than or equal to 2 mm.

4. The proportional electromagnet according to claim 3, characterized in that Delta Y is less than 2R.

5. The proportional electromagnet of claim 1, wherein The TMR sensor comprises a first terminal, a second terminal, a third terminal and a fourth terminal, and the first terminal and the second terminal, the second terminal and the third terminal, the third terminal and the fourth terminal and the fourth terminal and the first terminal are respectively connected in series with the magnetoresistance effect detecting element used for changing the resistance value of the magnetoresistance effect detecting element with the size of the external magnetic field.

6. An electromagnetic valve characterized by comprising: The application relates to a proportional electromagnet.

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