Electromagnet moving iron position monitoring device

Abstract

An electromagnet moving iron position monitoring device is provided with a metal magnetic core rod sleeve, an electromagnetic coil assembly is sleeved outside the sleeve, and a moving iron is arranged inside the sleeve. When the electromagnetic coil is electrified, electromagnetic force is generated to enable the moving iron to move axially; a detection element is arranged in the sleeve to detect the position of the moving iron; a detachable processing circuit assembly with an annular shell is arranged on the sleeve in a sleeving manner; an annular shell of the processing circuit assembly is provided with a spring contact and a guide key, and the sleeve is provided with a corresponding guide key groove; a lead of the detection element penetrates through the sleeve wall and is connected to a conducting strip on the outer wall of the sleeve; when the processing circuit assembly is installed on the sleeve, the guide key is engaged with the guide key groove on the sleeve, so that the spring contact is aligned and connected with the conducting strip.

Description

Technical Field

[0001] This invention relates to an electromagnet, particularly an electromagnet for a hydraulic or pneumatic solenoid directional valve. The electromagnet has a metal magnetic core rod sleeve (referred to herein as the sleeve), one end of which is mounted on the valve body, and the other end has a tail plug. The sleeve contains a detachable electromagnetic coil assembly, including an electromagnetic coil coil frame and an electromagnetic coil housing. Inside the sleeve is a moving iron. When the electromagnetic coil is energized, it generates electromagnetic force that causes the moving iron to move axially, which in turn pushes the valve core of the solenoid valve via a push rod. Background Technology

[0002] When the solenoid directional valve is working, the moving iron inside the sleeve of the electromagnet core may get stuck, causing the solenoid directional valve to malfunction. Sometimes the solenoid coil may also overheat and burn out. Summary of the Invention

[0003] To prevent the above problems and to monitor the position of the moving iron and the working status of the electromagnetic coil in real time, this invention provides an electromagnet moving iron position monitoring device.

[0004] The electromagnet has one or more detection elements embedded within the sleeve cavity. These detection elements are metal electrodes, spring pins, or inductor coils, each located at a specific position to be monitored. When the moving iron moves, approaches, or contacts a detection element, the signal from the detection element is transmitted via a lead through the sleeve wall and spring contacts to the processing circuit assembly, which then determines the position of the moving iron.

[0005] The reason for placing the detection element inside the sleeve, rather than using photoelectric or inductive detection methods from the outside, is that the sleeve contains high-pressure oil. The moving iron moves frequently within this enclosed high-pressure oil environment. Extending the moving iron's moving part out of the sleeve for detection would require a sealing ring and would increase the size of the electromagnet. The sealing ring would also impede the movement of the moving iron and pose a risk of wear and oil leakage.

[0006] The detection element is made of materials such as copper sheet, iron sheet, and enameled wire, and can be square, round, or ring-shaped. It can be a metal induction ring, a spring pin that makes direct elastic contact with the moving iron, or an inductor coil made of enameled wire.

[0007] The metal sensing ring is a circular metal ring, 0.05–3 mm thick and 0.1–20 mm wide. Its inner diameter is 0.1–1 mm larger than the outer diameter of the moving iron, allowing the moving iron to pass through the circular metal ring without contact. The sensing element is insulated from the sleeve, and both the moving iron and the sleeve are made of metal and are always in contact and conducting. When the moving iron penetrates the inner hole of the sensing element, the capacitance of the sensing element increases.

[0008] Metal induction rings can also be made by winding enameled wire into the shape of an inductor coil, with one or both ends of the wire used directly as leads. The wire diameter of the inductor coil is 0.05–3 mm, the number of turns is 1–20, and the inner diameter of the inductor coil is 0.1–1 mm larger than the outer diameter of the moving iron.

[0009] The detection element is embedded in the inner wall of the sleeve. An insulating material is used to electrically isolate the detection element from the sleeve, and this insulating material also serves to support, fix, and seal the element. The insulating material is epoxy resin or plastic. The lead wire of the detection element is led through a through-hole in the sleeve wall to a conductive plate on the outer surface of the sleeve. A key feature of this patent is that the conductive plate is circular, elliptical, or rectangular, embedded in the outer surface of the sleeve 4, and insulated from it. The conductive plate has dimensions (length, width, or diameter) of 1–10 mm and a thickness of 0.01–3 mm. It is made of conductive materials such as copper, aluminum, stainless steel, or lead-tin alloy, and can be surface-plated. The insulating material between the conductive plate and the sleeve is fiberglass board, epoxy resin, or plastic.

[0010] Coupled to the conductive sheet are spring contacts located on the housing of the processing circuit assembly, which relay the signal from the detection element to the processing circuit assembly. The spring contact has a metal pin with a diameter of 0.4 to 10 mm, and a spring at the rear end of the pin. The compression stroke of the spring pin is 0.1 to 10 mm.

[0011] To ensure circumferential alignment between the spring contacts on the processing circuit assembly housing and the conductive plates on the sleeve, a guide key is provided on the processing circuit assembly housing, and a matching guide keyway is provided on the sleeve, allowing the processing circuit assembly to be circumferentially oriented and mounted on the sleeve. The guide key has a thickness of 0.3–3 mm, a width of 1–10 mm, and extends 0.3–5 mm. The guide keyway has a depth of 0.3–3 mm and a width 0.01–2 mm greater than the guide key width.

[0012] Along the axial direction of the sleeve, the processing circuit assembly is mounted in a fixed position, such as between the electromagnetic coil housing and the end cap, and its axial position is determined. This ensures that the spring contacts and the conductive sheet are axially aligned.

[0013] The signal transmission path from the detection element to the processing circuit assembly is: detection element → lead wire → conductive sheet → spring contact → processing circuit assembly.

[0014] The processing circuit assembly has a ring-shaped housing that fits onto a sleeve. Its shape can be circular or non-circular, such as square or other shapes. To transmit multiple signals, multiple pairs of spring contacts and conductive plates can be arranged on the circumferential surface.

[0015] To ensure good contact between the spring contacts and the conductive sheet, as well as insulation from the housing, and to prevent impurities such as water and oil from entering, sealing rings are provided on the mating surfaces of the processing circuit assembly housing and the sleeve, and on one or both sides of the conductive sheet. O-rings or other types of sealing rings can be used.

[0016] To visually observe the operating status, at least one indicator light is installed on the casing of the processing circuit assembly to indicate the operating status or the position of the moving iron. The indicator light is an LED (light-emitting diode), which can be single-color, dual-color, or tri-color. Three different colored single-color LEDs can be used to indicate different states, for example, a green LED indicates power on, a red LED indicates the moving iron is at the left position, and a blue LED indicates the moving iron is at the right position. A single green LED can indicate power, while a single red-blue dual-color indicator light indicates both positions of the moving iron; red indicates the left position, and blue indicates the right position. Two red-green-blue tri-color LEDs can be arranged on either side of the processing circuit assembly to indicate the operating status; red indicates the moving iron is at the left position, blue indicates the right position, and green indicates the center position. Various combinations of colors can be created by adjusting the drive current using dual-color or tri-color LEDs to indicate different positions of the moving iron. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0018] Figure 2 This is a schematic diagram of the sleeve of the present invention.

[0019] Figure 3 This is an outline drawing of the processing circuit assembly of the present invention.

[0020] Figure 4 This is a schematic diagram of the moving iron position in the implementation plan.

[0021] Figure 5 This is the circuit schematic diagram of the implementation plan.

[0022] In the above attached diagram, 1-electromagnetic coil; 2-electromagnetic coil frame; 3-detection element; 4-sleeve; 5-moving iron; 6-valve body; 7-guide key; 8-processing circuit assembly; 9-conductive sheet; 9'-conductive sheet; 10-spring contact; 10'-spring contact; 11-sealing ring; 11'-sealing ring; 13-tail plug; 14-lead wire; 14'-lead wire; 15-electromagnetic coil housing; 16-electromagnetic coil assembly; 17-insulating layer; 18-guide keyway; 19-tail cap; 20-cable; 21-indicator light; 21'-indicator light. Detailed Implementation

[0023] An electromagnet with a moving iron position monitoring function has a metal magnetic core sleeve 4. One end of the sleeve 4 is mounted on a valve body 6, and the other end has a tail plug 13. An electromagnetic coil assembly 16 is fitted around the sleeve 4. The electromagnetic coil assembly 16 consists of an electromagnetic coil 1, an electromagnetic coil frame 2, and an electromagnetic coil outer shell 15. The electromagnetic coil assembly 16 can be removed from the sleeve 4, and the tail cap 19 presses and fixes the electromagnetic coil assembly 16 onto the sleeve 4. There is a moving iron 5 inside the sleeve 4; when the electromagnetic coil 1 is energized, it generates electromagnetic force to move the moving iron 5.

[0024] This implementation plan is as follows: Figure 1 As shown, a detachable processing circuit assembly 8 with a circular outer shell is inserted between the electromagnetic coil assembly 16 and the tail cap 19, fitted onto the sleeve 4, and pressed and fixed by the tail cap 19. Two circular detection elements 3 are embedded in the inner wall of the sleeve 4. The detection element 3 is circular, made of brass, 1mm wide, and 0.3mm thick. Its inner diameter is slightly larger than the diameter of the moving iron 5, and the gap between it and the moving iron is 0.1-0.3mm. The detection element 3 is electrically isolated and fixed to the inner wall of the sleeve 4 by an epoxy resin insulating layer 17. The detection element 3 is connected to a conductive plate 9 on the outer surface of the sleeve 4 via a lead wire 14. The conductive plate 9 is embedded in the outer surface of the sleeve 4, with an epoxy resin insulating layer 17 between it and the sleeve 4. The conductive plate 9 is circular, made of brass, 4mm in diameter, and 0.5mm thick. Two conductive plates 9 and 9' are arranged circumferentially on the outer surface of the sleeve 4, connecting to the left and right detection elements 3 respectively. On the inner circle of the outer casing of the processing circuit assembly 8, there are two corresponding spring contacts 10 and 10', which are coupled to the conductive plates 9 and 9' respectively, introducing the signals of the two detection elements 3 to the processing circuit assembly 8. The spring contact 10 is cylindrical with a diameter of 3mm, a semi-circular front end, and a spring pressing at the rear end with a telescoping range of 2mm. The material is gold-plated brass.

[0025] When the moving iron 5 moves close to or passes through the positions of the left and right detection elements 3 respectively, the capacitance of the detection element 3 will change. The processing circuit assembly 8 monitors the change in the capacitance value of the detection element 3 and outputs the position signal of the moving iron 5 to the outside through the cable 20, and the position is displayed by indicator lights 21 and 21'.

[0026] There are two indicator lights 21 and 21' on the outer circular surface of the processing circuit assembly 8. Each indicator light 21 and 21' contains three LEDs. LED1 and LED1' emit red light, LED2 and LED2' emit green light, and LED3 and LED3' emit blue light.

[0027] When working, the moving iron 5 has two positions inside the sleeve 4. When the electromagnetic coil 1 is energized, the moving iron 5 is attracted to the leftmost position (see attached image). Figure 4 A) When electromagnetic coil 1 is de-energized, moving iron 5 is pushed back to the right position by spring (see attached). Figure 4B). The two detection elements 3 are annular and spaced apart on the right side of the moving iron 5. Their inner diameters are slightly larger than the diameter of the moving iron 5, allowing the moving iron 5 to pass through the two detection elements 3. When the moving iron 5 is in its leftmost position, both detection elements 3 are located outside the right end face of the moving iron 5 and do not coincide with it, as shown in the attached diagram. Figure 4 As shown in Figure A.

[0028] When the moving iron 5 is in the right-end position, the moving iron 5 passes through the two detection elements 3 and coincides with both detection elements 3, as shown in the attached figure. Figure 4 As shown in Figure B. Compared to when they are not aligned, when the detection element 3 aligns with the moving iron 5, the capacitance of the detection element 3 increases. When the capacitance of both detection elements increases, it indicates that both detection elements 3 align with the moving iron 5, and the moving iron 5 is in the right-hand position. When the capacitance of neither detection element 3 increases, it indicates that neither detection element 3 aligns with the moving iron 5, and the moving iron 5 is in the left-hand position. When the capacitance of one detection element 3 increases while the other does not, it indicates that the moving iron 5 is positioned between the two electrodes.

[0029] The circuit principle of the implementation scheme is attached. Figure 5 As shown. The signal transmission path is: detection element 3 → lead wire 14 → conductive sheet 9 → spring pin 10 → processing circuit assembly 8. Inside the processing circuit assembly 8, the capacitance value of detection element 3 is detected using a microcontroller (MCU) with a capacitance sensing module (CPS). The signal from detection element 3 is connected to the capacitance detection input pin of the microcontroller. The microcontroller detects the changes in the two capacitance values, and after logical judgment, outputs a high level on the corresponding output pin. When the capacitance values ​​of both detection elements 3 do not increase, the microcontroller drives the output transistor T1 to conduct and illuminates LED1 and LED1', while indicator lights 21 and 21' emit red light, indicating that the moving iron 5 is currently in the left position. When the capacitance values ​​of both detection elements 3 increase, the microcontroller drives the output transistor T2 to conduct and illuminates LED2 and LED2', while indicator lights 21 and 21' emit green light, indicating that the moving iron 5 is currently in the right position. LED3 and LED3' emit blue light and are always connected between the positive and negative power supplies. When indicator lights 21 and 21' emit a blue light component, it indicates that the power supply is on and the circuit is in working condition. The power supply and output lines of the processing circuit component 8 are led out from cable 20.

[0030] There are two sealing rings 11 and 11' between the housing of the processing circuit assembly 8 and the sleeve 4. These two sealing rings 11 and 11' are O-rings made of nitrile rubber and are located on both sides of the conductive sheets 9 and 9' respectively. They can prevent oil, water and other debris from entering the area of ​​the conductive sheets 9 and 9' to avoid poor contact with the spring contacts 10 and 10' or leakage to the housing.

Claims

1. An electromagnet moving iron position monitoring device, comprising a metal magnetic core rod sleeve (4), an electromagnetic coil assembly (16) on the outside of the sleeve (4), and a moving iron (5) inside the sleeve (4). When the electromagnetic coil assembly (16) is energized, it generates electromagnetic force to move the moving iron (5) axially. Inside the sleeve (4), there is a detection element (3) to detect the position of the moving iron (5). The lead wire (14) of the detection element (3) passes through the sleeve wall and connects to a conductive sheet (9) on the outer surface of the sleeve (4). A detachable processing circuit assembly (8) with an annular outer shell is fitted onto the sleeve (4). A spring contact (10) on the inner hole of the outer shell of the processing circuit assembly (8) contacts and conducts electricity with the conductive sheet (9) on the outer surface of the sleeve (4). The device is characterized in that: The processing circuit assembly (8) has a guide key (7) on its housing and a matching guide keyway (18) on its sleeve (4), so that the processing circuit assembly (8) is oriented and mounted on the sleeve (4).

2. The apparatus according to claim 1, further characterized in that: The conductive sheet (9) is round, elliptical or rectangular, embedded on the outer surface of the sleeve (4) and insulated from the sleeve (4).

3. The apparatus according to claim 1, further characterized in that: There is a sealing ring (11) between the housing of the processing circuit assembly (8) and the sleeve (4).

4. The apparatus according to claim 1, characterized in that: The processing circuit assembly (8) has at least one indicator light (20) on its housing to indicate the working status or the position of the moving iron (5).

5. The apparatus according to claim 1 or 4, characterized in that: The indicator lights (20) on the housing of the processing circuit assembly (8) use different luminous colors to indicate the working status or different positions of the moving iron (5).

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