Variable pole area electromagnet

Abstract

The application belongs to the technical field of electromagnetic control volume pumps, and discloses a variable magnetic pole area electromagnet which comprises an electromagnet coil, an iron core, an armature, a top rod, a diaphragm and a diaphragm housing, the iron core is fixed to the inner lower part of the electromagnet coil, the top part of the iron core is provided with a magnetic isolation sheet, the top rod penetrates the shaft center of the iron core and the magnetic isolation sheet, the lower part of the top rod is sleeved with a compression spring, the lower part of the compression spring is fixed to the diaphragm housing, the bottom of the top rod is connected with the diaphragm to drive the diaphragm to move up and down, the armature is arranged on the inner upper part of the electromagnet coil, the armature comprises an outer armature and an inner armature, the outer armature is provided with a groove around the shaft center, and the inner armature is arranged in the groove, the top part of the top rod is in contact with the shaft center of the outer armature, the sectional area of the top rod is greater than the sectional area of the shaft center of the outer armature and smaller than the sectional area of the groove, and the top rod protrudes from the shaft center of the outer armature to support the inner armature. The application solves the problems that the initial electromagnetic force of the existing planar magnetic pole electromagnet is small and the terminal electromagnetic force is large.

Description

Technical Field

[0001] This invention belongs to the technical field of electromagnetically controlled volumetric pumps, and more specifically, relates to a variable magnetic pole area electromagnet. Background Technology

[0002] NO x With increasingly stringent emission limits, the requirements for diesel engine exhaust aftertreatment are becoming more stringent. Electromagnetic diaphragm pumps rely on electromagnetic attraction and a return spring to drive the diaphragm in reciprocating motion. The diaphragm's elastic deformation causes periodic changes in the working chamber volume to draw in or discharge liquid. A key feature is that the diaphragm isolates the drive unit from the pumped liquid, eliminating dynamic seal wear issues and providing excellent sealing performance. It is widely used in diesel engine SCR urea supply units. Compared to traditional electric motor diaphragm pumps, the electromagnetic diaphragm pump's armature is directly connected to the diaphragm, eliminating the need for complex transmission mechanisms. This results in a simpler structure, more reliable operation, and higher cost-effectiveness. The reciprocating linear motion of the armature matches the motion pattern of the diaphragm center, balancing the electromagnetic force and diaphragm pressure, and eliminating radial forces, significantly improving the diaphragm's stress state and deformation.

[0003] Planar magnetic pole electromagnets are commonly used power components in electromagnetic diaphragm pumps. However, the rapidly changing attraction characteristics of planar magnetic pole electromagnets are mismatched with the relatively constant load characteristics of electromagnetic diaphragm pumps. When the initial electromagnetic force is greater than the diaphragm pump load, the excessively large final electromagnetic force can easily cause impact and noise in the electromagnet. Especially when there is no liquid or load in the pump chamber, the impact force of the armature may damage the weld between the iron core and the sleeve, and also cause significant damage to the diaphragm. Therefore, the attraction characteristics of planar magnetic pole electromagnets need to be improved. Currently, in order to increase the initial electromagnetic force and reduce the final electromagnetic force, various electromagnetic diaphragm pump drive electromagnets have been developed in the industry. In a comparative analysis of the dynamic characteristics of a high-speed electromagnet with conical and planar magnetic poles (Transactions of the Chinese Society for Agricultural Machinery, 2009, 40(3): 213-217), when the cone angle of the armature decreases, the final electromagnetic force decreases accordingly, but the initial electromagnetic force also decreases. A study on the characteristics of a DC constant force electromagnet (Transactions of the Chinese Society for Mechanical Engineering, 2008, 44(2): 244-247) discloses the construction of a non-working [electromagnet] between the yoke and the armature. The air gap is connected in series with the main working air gap to obtain a relatively flat electromagnetic attraction-air gap curve, but the magnetic resistance increases and the initial electromagnetic attraction decreases; A study on a low-power force-controlled proportional electromagnet (Journal of Coal Science and Technology, 2009, 34(6): 849-852) proposed an electromagnet with a stepped armature structure. The outer ring is the main working area, and the overlapping area of ​​the inner cylinder and the iron core hole constitutes the leakage magnetic air gap. When the air gap of the main working area decreases, the area of ​​the leakage magnetic area increases, which can keep the air gap magnetic flux and electromagnetic force of the main working area basically stable, but the initial electromagnetic force does not increase. Summary of the Invention

[0004] In view of the above-mentioned defects or improvement needs of the existing technology, the present invention provides a variable magnetic pole area electromagnet, which solves the problem that the initial electromagnetic force of the existing planar magnetic pole electromagnet is small and the final electromagnetic force is large.

[0005] To achieve the above objectives, according to one aspect of the present invention, a variable pole area electromagnet is provided, comprising an electromagnet coil, an iron core, an armature, a push rod, a diaphragm, and a diaphragm housing, wherein: the iron core is fixed to the lower inner part of the electromagnet coil and a magnetic shielding sheet is provided on the top of the iron core; the push rod passes through the axis of the iron core and the magnetic shielding sheet; a compression spring is sleeved on the lower part of the push rod, the lower part of the compression spring is fixed to the diaphragm housing, and the bottom of the push rod is connected to the diaphragm to drive the diaphragm to move up and down, thereby changing the pressure in the working chamber of the diaphragm; the armature is disposed in the upper inner part of the electromagnet coil, the armature comprising an outer armature and an inner armature, a groove is provided around the axis of the outer armature, and the inner armature is disposed in the groove; the top of the push rod contacts the axis of the outer armature, and the cross-sectional area of ​​the push rod is larger than the cross-sectional area of ​​the axis of the outer armature and smaller than the cross-sectional area of ​​the groove, thereby the push rod protrudes from the axis of the outer armature to support the inner armature.

[0006] In a further preferred embodiment, the cross-section of the magnetic shielding sheet has the same shape as the cross-section of the inner armature, and the cross-sectional area of ​​the magnetic shielding sheet is less than or equal to the cross-sectional area of ​​the inner armature.

[0007] In a further preferred embodiment, the magnetic shielding sheet is annular, loop-shaped, or a regular polygon. In a further preferred embodiment, in the power-off state, the gap between the magnetic shielding sheet and the inner armature is greater than the minimum stroke of the diaphragm but less than the maximum stroke of the diaphragm, and the gap between the outer armature and the iron core is equal to the maximum working stroke of the diaphragm.

[0008] In a further preferred embodiment, the inner armature shaft is a hollow cylinder, and the outer armature shaft is a cylinder.

[0009] Another embodiment of this application provides a variable pole area electromagnet, including an electromagnet coil, an iron core, an armature, a push rod, a diaphragm, and a diaphragm housing, wherein: the iron core is fixed to the lower inner part of the electromagnet coil, and a magnetic shielding sheet is provided on the top of the iron core; the push rod passes through the axis of the iron core and the magnetic shielding sheet; a compression spring is sleeved on the lower part of the push rod, and the lower part of the compression spring is fixed to the diaphragm housing; the bottom of the push rod is connected to the diaphragm to drive the diaphragm to move up and down, thereby changing the pressure in the working chamber of the diaphragm; the armature is disposed in the upper inner part of the electromagnet coil, and the armature includes an outer armature and an inner armature; a groove is provided around the axis of the outer armature, and the inner armature is disposed in the groove; the top of the inner armature is connected to the top of the groove by a spring; the top of the push rod contacts the axis of the outer armature, and the cross-sectional area of ​​the push rod is less than or equal to the cross-sectional area of ​​the axis of the outer armature.

[0010] In a further preferred embodiment, under power-off conditions, there is a gap between the inner armature and the magnetic shielding sheet, and the height of the gap is greater than the minimum stroke of the diaphragm but less than the maximum stroke of the diaphragm.

[0011] In summary, compared with the prior art, the variable pole area electromagnet for urea diaphragm pumps provided by the present invention has the following beneficial effects:

[0012] 1. The armature of this application adopts a combination structure of inner and outer armatures. During the descent of the armature, when the inner armature contacts the magnetic shielding sheet, the magnetism of the inner armature is isolated, thereby reducing the magnetic pole area of ​​the electromagnet. As a result, the electromagnet with a variable magnetic pole area has a larger initial electromagnetic force and a smaller final electromagnetic force, which can better adapt to the load characteristics of the electromagnetic diaphragm pump, reduce the impact, noise and overheating of the electromagnet and improve the service life of the electromagnetic diaphragm pump.

[0013] 2. The magnetic shielding sheet of this application can be adjusted as needed to meet different magnetic performance requirements, and has strong versatility and wide applicability.

[0014] 3. This application achieves magnetic force change through a spring, an inner armature, and a magnetic shield, avoiding the introduction of additional power, and is simple and easy to operate. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the variable pole area electromagnet in the first scheme of this application.

[0016] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0017] 1-Pump body; 2-Inlet check valve; 3-Outlet check valve; 4-Diaphragm; 5-Working chamber; 6-Compression spring; 7-Electromagnet coil; 8-Push rod; 9-Iron core; 10-Magnetic shield; 11-Inner armature; 12-Outer armature; 13-Diaphragm housing. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0019] The first aspect of this invention provides a variable pole area electromagnet, wherein the armature of this application adopts an inner and outer combined structure. When the electromagnet coil is energized, the electromagnetic forces generated by the inner and outer armatures work together to drive the diaphragm to move. Since the initial working air gap of the inner armature is small, the initial electromagnetic force generated by the inner and outer armatures is large. When the inner armature touches the magnetic isolation ring, the inner armature stops moving, and the electromagnetic force of the electromagnet is equal to the electromagnetic attraction force of the annular outer armature, which is less than the electromagnetic attraction force of a single planar magnetic pole electromagnet. Therefore, it can solve the problem of the small initial electromagnetic force and the large final electromagnetic force of planar magnetic pole electromagnets. This variable pole area electromagnet mainly includes an electromagnet coil 7, an iron core 9, an armature, a push rod 8, a diaphragm 4, and a diaphragm housing 13, the specific structure of which is as follows.

[0020] The iron core 9 is fixed to the lower inner part of the electromagnet coil 7, and a magnetic shielding sheet 10 is provided on the top of the iron core 9. The top rod 8 passes through the axis of the iron core 9 and the magnetic shielding sheet 10. The function of the magnetic shielding sheet is to maintain a certain magnetic resistance between the inner armature and the iron core during the armature attraction process, and to maintain a certain magnetic potential between the outer armature and the iron core.

[0021] The lower part of the push rod 8 is fitted with a compression spring 6, the lower part of the compression spring 6 is fixed to the diaphragm housing 13, and the bottom of the push rod 8 is connected to the diaphragm 4 to drive the diaphragm to move up and down, thereby changing the pressure in the working chamber of the diaphragm 4.

[0022] The armature is disposed in the upper inner part of the electromagnet coil. The armature includes an outer armature 12 and an inner armature 11. The outer armature 12 has a groove around its axis, and the inner armature 11 is disposed in the groove.

[0023] The top of the push rod 8 contacts the axis of the outer armature 12, and the cross-sectional area of ​​the push rod 8 is larger than the cross-sectional area of ​​the axis of the outer armature 12 but smaller than the cross-sectional area of ​​the groove. Thus, the push rod 8 protrudes from the axis of the outer armature 12 to support the inner armature 11. In the de-energized state, there is a gap between the upper part of the inner armature 11 and the top of the groove, allowing the inner armature 11 to move up and down within the groove. Two working air gaps are formed between the armature and the iron core. The working air gap of the outer armature is equal to the diaphragm pump stroke, while the working air gap of the inner armature is always smaller than that of the outer armature. Therefore, in the initial stage, the sum of the electromagnetic attraction forces of the inner and outer armatures is greater than the electromagnetic attraction force of a single planar armature. In the final stage, the stroke of the inner armature is restricted by the magnetic isolation ring, and the electromagnetic force of the electromagnet is only equal to the electromagnetic attraction force of the annular outer armature, which is less than the electromagnetic attraction force of a single planar armature. The armature is connected to the diaphragm via a push rod. Under the alternating action of electromagnetic attraction and return spring, it drives the diaphragm to reciprocate, changing the volume of the working chamber between the diaphragm 4 and the pump body 1, thereby realizing the intake and discharge of liquid.

[0024] In a further preferred embodiment, the initial working air gap of the outer armature is equal to the maximum working stroke of the diaphragm pump, and the initial working air gap of the inner armature is smaller than the initial working air gap of the outer armature.

[0025] In a further preferred embodiment, the cross-section of the magnetic shielding sheet has the same shape as the cross-section of the inner armature, and the cross-sectional area of ​​the magnetic shielding sheet is less than or equal to the cross-sectional area of ​​the inner armature.

[0026] In a further preferred embodiment, the magnetic shielding sheet is annular, spiral-shaped, or a regular polygon, and the corresponding cross-sectional shape of the inner armature is annular, spiral-shaped, or a regular polygon, with annular being a further preferred embodiment.

[0027] In a further preferred embodiment, the inner armature shaft is a hollow cylinder, and the outer armature shaft is a cylinder.

[0028] In a further preferred embodiment, under power-off conditions, the gap between the magnetic shielding sheet and the inner armature is greater than the minimum stroke of the diaphragm but less than the maximum stroke of the diaphragm.

[0029] During operation, when the electromagnet coil 7 is de-energized, the push rod 8 and armature reset under the spring force of the compression spring 6, causing the diaphragm 4 to move upward. This increases the volume of the working chamber, reducing the pressure to below atmospheric pressure, and the inlet check valve 2 opens, allowing liquid to be drawn into the working chamber 5. When the electromagnet coil 7 is energized, the armature is attracted by electromagnetic force, pushing the push rod 8 and diaphragm 4 downward. This reduces the volume of the working chamber, increases the pressure, and the outlet check valve 3 opens, allowing liquid to be discharged from the working chamber 5. The armature stroke is divided into two stages. In the initial stage, the inner armature 11 and the outer armature 12 jointly push the diaphragm 4. After the inner armature 11 contacts the magnetic shielding plate 10, only the outer armature 12 is attracted by electromagnetic force, allowing the diaphragm 4 to continue working. Using a PWM power supply, the armature is driven to reciprocate linearly within the guide sleeve, driving the diaphragm pump to draw in and discharge liquid, achieving continuous fluid output. The output flow rate of the electromagnetic diaphragm pump can be controlled by adjusting the frequency of the PWM power supply.

[0030] Another aspect of the present invention provides a variable pole area electromagnet, which includes an electromagnet coil, an iron core, an armature, a push rod, a diaphragm, and a diaphragm housing, wherein:

[0031] The iron core is fixed to the lower inner part of the electromagnet coil and a magnetic shielding sheet is provided on the top of the iron core. The top rod passes through the axis of the iron core and the magnetic shielding sheet.

[0032] The lower part of the push rod is fitted with a compression spring, the lower part of the compression spring is fixed to the diaphragm housing, and the bottom of the push rod is connected to the diaphragm to drive the diaphragm to move up and down, thereby changing the pressure in the working chamber of the diaphragm.

[0033] The armature is disposed in the upper inner part of the electromagnet coil. The armature includes an outer armature and an inner armature. The outer armature has a groove around its shaft, and the inner armature is disposed in the groove.

[0034] The top of the inner armature is connected to the top of the groove by a spring;

[0035] The top of the push rod is in contact with the axis of the outer armature, and the cross-sectional area of ​​the push rod is less than or equal to the cross-sectional area of ​​the axis of the outer armature.

[0036] In a further preferred embodiment, under power-off conditions, there is a gap between the inner armature and the magnetic shielding sheet, and the height of the gap is greater than the minimum stroke of the diaphragm but less than the maximum stroke of the diaphragm. The gap between the outer armature and the iron core is equal to the maximum working stroke of the diaphragm.

[0037] The difference between this embodiment and the above embodiments is that this embodiment uses a spring to connect the inner armature to overcome the problem that the inner armature will fall downward due to gravity. Its working principle is the same as that of the first scheme, and will not be described again here.

[0038] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements 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 diaphragm pump having a variable pole area electromagnet, characterized by, It includes an electromagnet coil (7), an iron core (9), an armature, a push rod (8), a diaphragm (4), and a diaphragm housing (13), wherein: The iron core is fixed to the lower inner part of the electromagnet coil (7) and a magnetic shielding sheet (10) is provided on the top of the iron core (9). The top rod (8) passes through the axis of the iron core (9) and the magnetic shielding sheet (10). The lower part of the top rod (8) is fitted with a compression spring (6), the lower part of the compression spring (6) is fixed to the diaphragm housing (13), and the bottom of the top rod (8) is connected to the diaphragm (4) to drive the diaphragm to move up and down and change the pressure in the working chamber of the diaphragm (4). The armature is disposed in the upper inner part of the electromagnet coil (7). The armature includes an outer armature (12) and an inner armature (11). The outer armature has a groove around its shaft, thus forming a shaft column at the shaft center. The inner armature (11) is disposed in the groove. The top of the push rod (8) contacts the axis of the outer armature, and the cross-sectional area of ​​the push rod (8) is larger than the cross-sectional area of ​​the axis and smaller than the cross-sectional area of ​​the groove. Thus, the push rod protrudes from the axis of the outer armature to support the inner armature. During the descent of the armature, when the inner armature (11) contacts the magnetic shielding sheet (10), the magnetism is isolated, the magnetic pole area decreases, and the magnetism of the armature decreases. In the power-off state, the gap between the magnetic shielding sheet (10) and the inner armature (11) is greater than the minimum stroke of the diaphragm and less than the maximum stroke of the diaphragm (4), and the gap between the outer armature (12) and the iron core (9) is equal to the maximum working stroke of the diaphragm (4).

2. The diaphragm pump with a variable pole area electromagnet according to claim 1, characterized in that The cross-section of the magnetic shielding sheet (10) has the same shape as the cross-section of the inner armature (11), and the cross-sectional area of ​​the magnetic shielding sheet (10) is less than or equal to the cross-sectional area of ​​the inner armature (11).

3. The diaphragm pump with a variable magnetic pole area electromagnet according to claim 1 or 2, characterized in that, The magnetic shielding sheet (10) is annular, spiral, or regular polygonal.

4. The diaphragm pump with a variable magnetic pole area electromagnet according to claim 1, characterized in that, The inner armature (11) has a hollow cylinder as its axis, and the outer armature (12) has a cylinder as its axis.

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