U-shaped magnetic spring device and counterweight mechanism

Abstract

The U-shaped magnetic spring device comprises a fixed part and a movable part, a first permanent magnet face and a fourth permanent magnet face of the fixed part are parallel to each other, a stroke groove is formed between the first permanent magnet face and the fourth permanent magnet face, the movable part is installed in the stroke groove to move and comprises an assembling part, and the assembling part is provided with a second permanent magnet face facing the first permanent magnet face. The second permanent magnet face is opposite to the first permanent magnet face in magnetic pole and provided with a first magnetic end face, the assembling portion is provided with a third permanent magnet face facing the fourth permanent magnet face, and the third permanent magnet face is opposite to the fourth permanent magnet face in magnetic pole and provided with a second magnetic end face. And a constant end magnetic force is generated with the fixed part, and a restoring elastic force with doubled power density is output. According to the U-shaped magnetic spring device, the four ends of the four-row magnetic steel structure are adopted to generate larger suction force and multiplied power density, the stroke is twice after stretching, the structure is simple, and the size is small.

Description

Technical Field

[0001] The present invention relates to the field of magnetic springs, and particularly to a U-shaped magnetic spring device and a counterweight mechanism. Background Art

[0002] Magnetic spring devices incorporate magnetic materials, typically elements such as iron, cobalt, and nickel, to form a certain magnetic field and magnetic moment, enabling the magnetic spring to generate a restoring magnetic force after deformation for use in controlling switches, triggering sensors, floating control, etc.

[0003] Magnetic spring devices, being passive components, can achieve a constant elastic force output without external air supply or power supply. Most are used as counterweights in vertical motion mechanisms. Traditional counterweight devices include mechanical springs, cylinders, or cylindrical magnetic springs. Mechanical springs use the tension of extension springs for counterweight, cylinders use cylinder pressure for counterweight, and cylindrical magnetic springs output force through the attraction between permanent magnets and magnetic conductive materials.

[0004] Existing counterweight devices still have the following deficiencies:

[0005] When using a mechanical spring for counterweight, the elastic force of the mechanical spring changes with the stretching length, and the output elastic force is uneven, generally only applicable to fixed positions or short-stroke counterweights.

[0006] When using a cylinder for counterweight, the counterweight device needs to be additionally connected to an external air source. The cylinder cannot provide protection in the event of a power outage, and the cylinder device is relatively long and requires a large amount of space.

[0007] Although cylindrical magnetic springs are also passive devices, due to the use of a single permanent magnet and magnetic conductive material, they have the defects of insufficient power density, relatively long length occupying more installation space, insufficient installation positions in many compact spaces, and a bulky structure. Summary of the Invention

[0008] The purpose of the present invention is to provide a U-shaped magnetic spring device and a counterweight mechanism to solve the problems of uneven elastic force, low precision, large occupied space, and low power density.

[0009] To achieve this purpose, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention relates to a U-shaped magnetic spring device, including a fixed member and a moving member. The fixed member is provided with a first permanent magnetic surface and a fourth permanent magnetic surface. The first permanent magnetic surface and the fourth permanent magnetic surface are parallel to each other and form a travel groove. The moving member can move in the travel groove and includes an assembly portion. The assembly portion faces the first permanent magnetic surface and is provided with a second permanent magnetic surface. The second permanent magnetic surface has the opposite magnetic pole (NS pole) to the first permanent magnetic surface and has a first magnetic end face. The assembly portion faces the fourth permanent magnetic surface and is provided with a third permanent magnetic surface. The third permanent magnetic surface has the opposite magnetic pole (NS pole) to the fourth permanent magnetic surface and has a second magnetic end face. When the moving member moves within the travel range relative to the fixed member, the first magnetic end face and the second magnetic end face generate a constant end magnetic force with the fixed member to continuously output a return elastic force (F) with twice the power density.

[0011] The lengths of the magnets of the first permanent magnetic surface and the fourth permanent magnetic surface on both sides of the travel groove and the second permanent magnetic surface and the third permanent magnetic surface in the middle of the travel groove are the same. This magnet length is half of the set travel length of the U-shaped spring device. The area from the first permanent magnetic surface to the fourth permanent magnetic surface is proportional to the return elastic force.

[0012] The return elastic force F is calculated by the following formula:

[0013]

[0014] Wherein, F represents the return elastic force, that is, the rebound suction force, B represents the magnetic induction intensity on the surface of the magnet, A represents the end face area of the first magnetic end face and the second magnetic end face, μ0 represents the magnetic permeability in vacuum, g represents the air gap width, w represents the width of the magnet perpendicular to the extraction direction dimension, and k represents the edge effect coefficient.

[0015] The magnetic induction intensity B is calculated according to the correction formula of the structural dimensions of the U-shaped magnetic spring device as:

[0016]

[0017] Wherein, B r represents the remanence of the permanent magnet; L m represents the magnet length; μ r represents the relative magnetic permeability of the magnet material; g represents the air gap width. In other embodiments, the first permanent magnetic surface is formed by splicing more than one first magnetic steel component in multiple rows and / or multiple columns, the second permanent magnetic surface is formed by splicing more than one second magnetic steel component in multiple rows and / or multiple columns, the third permanent magnetic surface is formed by splicing more than one third magnetic steel component in multiple rows and / or multiple columns, and the fourth permanent magnetic surface is formed by splicing more than one fourth magnetic steel component in multiple rows and / or multiple columns.

[0018] The fixing member includes a base, a first fixing plate and a second fixing plate extending from the base. A first assembly step is provided on the inner side of the first fixing plate, and the first magnet assembly is positioned by the first assembly step and bonded to the first fixing plate with high-strength structural adhesive; a fourth assembly step is provided on the inner side of the second fixing plate, and the fourth magnet assembly is positioned by the fourth assembly step and bonded to the second fixing plate with high-strength structural adhesive.

[0019] The moving member includes a connecting portion, and an assembling portion is provided below the connecting portion. Second and third assembly steps are provided on both sides of the assembling portion. The second magnet assembly is positioned on the second assembly step and bonded to one side of the assembling portion with high-strength structural adhesive; the third magnet assembly is positioned on the third assembly step and bonded to the other side of the assembling portion with high-strength structural adhesive.

[0020] Wherein, the base of the fixing member includes a machine base connection structure, and the connecting portion of the moving member includes a counterweight connection structure.

[0021] Preferably, an air gap is provided between the first permanent magnetic surface and the opposite second permanent magnetic surface, and the range of the width of the air gap is 0.1 mm to 0.3 mm.

[0022] In a second aspect, the present invention relates to a counterweight mechanism, including at least one U-shaped magnetic spring device described in the first aspect.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] Beneficial effect 1: The U-shaped magnetic spring device of this embodiment belongs to a passive structure and does not require additional gas sources, power sources, etc., which is energy-saving and environmentally friendly. The fixing member is U-shaped, and the moving member is T-shaped and elastically moves by inserting into the U-shaped travel groove, with a simple structure. Two independent permanent magnets are provided on both sides of the moving member, which are magnetically attracted to the two permanent magnets on the inner wall surface of the travel groove, doubling the interaction force of the permanent magnets. Moreover, the length of the permanent magnet and the structural dimensions of the spring are associated with the magnetic induction intensity and are associated with the magnitude of the restoring elastic force to output a constant end magnetic force, and the magnetic force accuracy can reach within ±1%.

[0025] Beneficial effect 2: The U-shaped magnetic spring device of this embodiment adopts four rows of permanent magnetic surfaces. When the moving member extends out of the fixing member, a total of four ends can generate suction force, generating a greater magnetic suction force per unit volume, and the power density is more than twice as high. The first to fourth permanent magnetic surfaces can be formed by splicing one or more magnet assemblies in multiple rows and / or multiple columns, and the increased magnetic attraction area can generate a greater elastic magnetic suction force.

[0026] Beneficial effect 3: In the U-shaped magnetic spring device of this embodiment, the stroke length is the effective stroke. When the moving part slides relative to the fixed part to the end, the total length of the spring device is close to 2 times the effective stroke; after the moving part is received into the fixed part, the length and volume are shortened by half. Compared with the existing spring device with a fixed stroke length, the size can be shortened by half and the volume is smaller. Since the total length is half shorter than the existing counterweight device, it is convenient for installation and can be installed more simply without occupying a large installation position. Brief Description of the Drawings

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0028] The structures, ratios, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the limited conditions under which the present invention can be implemented. Therefore, they do not have technical essence. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope that can be covered by the technical content disclosed by the present invention.

[0029] Figure 1 It is the first three-dimensional structure diagram of the U-shaped magnetic spring device of the present invention;

[0030] Figure 2 It is the second three-dimensional structure diagram of the U-shaped magnetic spring device of the present invention;

[0031] Figure 3 It is the end face structure diagram of the U-shaped magnetic spring device of the present invention;

[0032] Figure 4 It is the side structure diagram of the moving part of the U-shaped magnetic spring device of the present invention extending out of the fixed part;

[0033] Figure 5 It is Figure 4 The sectional magnetic force line distribution diagram along the C-C section line in

[0034] Figure 6 It is the layout schematic diagram of the first to fourth permanent magnetic surfaces of the U-shaped magnetic spring device of the present invention;

[0035] Figure 7 It is the magnetic field distribution schematic diagram of the first to fourth permanent magnetic surfaces of the U-shaped magnetic spring device of the present invention;

[0036] Figure 8This is the magnetic force simulation analysis diagram of the U-shaped magnetic spring device of the present invention using the simulation software ANSYS;

[0037] Figure 9 This is the schematic diagram of other magnetic pole structures of the U-shaped magnetic spring device of the present invention;

[0038] Figure 10 This is the parameter description diagram of the U-shaped magnetic spring device of the present invention.

[0039] Illustration:

[0040] Fixing part 1; First permanent magnetic surface 2, 200; Fourth permanent magnetic surface 3; Moving part 5; Second permanent magnetic surface 6, 600; Third permanent magnetic surface 7; Base 10; Fixing hole 101; First fixing plate 11; Second fixing plate 12; First magnet assembly 21, 22, 211, 221, 231, 211, 212, 213, 214; Fourth magnet assembly 31, 32; Connecting part 50; Assembling part 51; First assembly step 115; Fourth assembly step 125; Second assembly step 501; Third assembly step 505; Connecting hole 506; Stroke groove 18; Air gap g; Magnet length L m ; Magnet width w; Stroke length D; Elastic force length D2; Moving magnetic pole module M; Recovery elastic force F. Detailed implementation manners

[0041] To make the invention purpose, features and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the embodiments described below are only a part of the embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0042] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be an intermediate component.

[0043] The technical solutions of the present invention will be further described below with reference to the accompanying drawings and through specific implementation manners.

[0044] Please refer to Figure 1 、 Figure 2 andFigure 4 , the U-shaped magnetic spring device of the embodiment of the present invention includes a fixed member 1 and a moving member 5 having a stroke length D.

[0045] Please refer to Figure 3 , the fixed member 1 is U-shaped with a hollow middle to form a stroke groove 18 for accommodating the moving member 5, including a base 10, a first fixing plate 11 and a second fixing plate 12 extending from the base 10. The fixed member 1 is provided with a first permanent magnetic surface 2 and a fourth permanent magnetic surface 3 having a magnet length L m . The lengths of the first fixing plate 11 and the second fixing plate 12 may not be limited by the stroke length, as long as the magnetic steel assembly can be stably installed.

[0046] During installation, a first assembly step 115 is provided inside the first fixing plate 11. The first permanent magnetic surface 2 is flatly positioned through the first assembly step 115 and bonded to the first fixing plate 11 with a high-strength structural adhesive. A fourth assembly step 125 is provided inside the second fixing plate 12. The fourth permanent magnetic surface 3 is flatly positioned through the fourth assembly step 125 and bonded to the second fixing plate 12 with a high-strength structural adhesive.

[0047] The moving member 5 includes a connecting portion 50, and an assembling portion 51 is provided below the connecting portion 50. Second permanent magnetic surfaces 6 and third permanent magnetic surfaces 7 having a magnet length L m are installed on the left and right sides of the assembling portion 51.

[0048] As Figure 10 shown, the magnet lengths L of the first permanent magnetic surface and the fourth permanent magnetic surface on both sides of the stroke groove 18 and the second permanent magnetic surface and the third permanent magnetic surface in the middle of the stroke groove 18 m are the same. The magnet length L m is half of the stroke length D set for the U-shaped spring device. The area from the first permanent magnetic surface to the fourth permanent magnetic surface is proportional to the restoring elastic force.

[0049] Second assembly steps 501 and third assembly steps 505 are provided on both sides of the assembling portion 51. The second permanent magnetic surface 6 is flatly positioned on the second assembly step 501 and bonded to one side of the assembling portion 51 with a high-strength structural adhesive; the third permanent magnetic surface 7 is positioned on the third assembly step 505 and bonded to the other side of the assembling portion 51 with a high-strength structural adhesive.

[0050] The first permanent magnet surface 2 and the fourth permanent magnet surface 3 are parallel to each other and form a stroke groove 18. The moving member 5 can move in the stroke groove 18. The assembling portion of the moving member 5 is located between the first fixing plate 11 and the second fixing plate 12. In terms of the positional relationship, the second permanent magnet surface 6 is arranged facing the first permanent magnet surface 2 at the assembling portion 51, and the second permanent magnet surface 6 has opposite magnetic poles (N-S poles) to the first permanent magnet surface 2. The third permanent magnet surface 7 is arranged facing the fourth permanent magnet surface 3 at the assembling portion 51, and the third permanent magnet surface 7 also has opposite magnetic poles (N-S poles) to the fourth permanent magnet surface 3. When the moving member 5 moves relative to the fixed member 1 within the stroke range determined by the stroke length D, a constant end magnetic force is generated with the fixed member 1, and a stable restoring elastic force F is continuously output.

[0051] Please refer to Figure 6 , the first permanent magnet surface 2 and the fourth permanent magnet surface 3 provided on the fixed member 1 are parallel to each other. The second permanent magnet surface 6 and the third permanent magnet surface 7 provided on the moving member 5 are parallel to each other. The first permanent magnet surface 2, the fourth permanent magnet surface 3, the second permanent magnet surface 6, and the third permanent magnet surface 7 are also parallel to each other. The second permanent magnet surface 6 and the third permanent magnet surface 7 form a moving magnetic pole module M that slides magnetically between the first permanent magnet surface 2 and the fourth permanent magnet surface 3.

[0052] Please refer to Figure 3 and Figure 5 , an air gap g is provided between the first permanent magnet surface 2 and the opposite second permanent magnet surface 6, and there is also an air gap g between the fourth permanent magnet surface 3 and the opposite third permanent magnet surface 7. The range value of the width g of the air gap g is 0.1 mm to 0.3 mm. For example, the S pole of the first permanent magnet surface 2 is close to the N pole of the second permanent magnet surface 6, and an air gap of 0.1 mm is maintained. The S pole of the third permanent magnet surface 7 is close to the N pole of the fourth permanent magnet surface 3, and an air gap of 0.1 mm is maintained.

[0053] In Figure 1 and Figure 2 In the illustrated embodiments, the first permanent magnet surface 2, the fourth permanent magnet surface 3, the second permanent magnet surface 6, and the third permanent magnet surface 7 are all provided as being formed by splicing two magnet components. For example, the first permanent magnet surface 2 is formed by splicing two first magnet components 21 and 22, and the sum of the lengths of the two first magnet components 21 and 22 is equal to half of the stroke length D / 2 of the spring device. The fourth permanent magnet surface 3 is formed by splicing two fourth magnet components 31 and 32, and the sum of the lengths of the two fourth magnet components 31 and 32 is also equal to half of the stroke length D / 2 of the spring device.

[0054] There are also many combinations of the first to fourth permanent magnet surfaces. In other embodiments, the first permanent magnet surface 2 may be formed by splicing more than one first magnet assembly in a multi-row and / or multi-column form. The second permanent magnet surface 6 may be formed by splicing more than one second magnet assembly in a multi-row and / or multi-column form. The third permanent magnet surface 7 may be formed by splicing more than one third magnet assembly in a multi-row and / or multi-column form. The fourth permanent magnet surface 3 may be formed by splicing more than one fourth magnet assembly in a multi-row and / or multi-column form. As Figure 9 shown in the second embodiment of the first permanent magnet surface and the second permanent magnet surface, the first permanent magnet surface 200 is formed by splicing 12 first magnet assemblies in a three-row (211, 221, 231) and four-column (for example, 211, 212, 213, 214) form. Among them, the sum of the lengths of the three first magnet assemblies (211, 221, 231) in the row is equal to half of the set stroke length D / 2. The opposite second permanent magnet surface 600 has the same magnetic pole structure as the first permanent magnet surface 200. Similarly, the third permanent magnet surface and the fourth permanent magnet surface have the same magnetic pole structure, which will not be elaborated here.

[0055] Please refer to Figure 6 , when the moving member 5 moves to the right and extends the elastic length D2 of the fixing member 1, the moving magnetic pole module M of the moving member 5 will generate a constant end magnetic suction force (F) with the magnetic pole module of the fixing member 1, so as to continuously output a stable return elastic force F. The range of the constant magnetic suction force depends on the lengths of the first to fourth permanent magnet surfaces (2, 3, 6, 7).

[0056] Please also refer to Figure 7 , in Figure 6 the shown state, the moving magnetic pole module M of the moving member 5 includes the second permanent magnet surface 6 and the third permanent magnet surface 7. The left end of the moving magnetic pole module M generates end magnetic suction forces with the first and second permanent magnet surfaces 2 and 3 of the fixing member 1 respectively due to the magnetic field change. Similarly, the right end of the moving magnetic pole module M generates end magnetic suction forces with the first and second permanent magnet surfaces 2 and 3 respectively due to the magnetic field change, and the end magnetic suction force will not change with the position change of the moving member 5 relative to the fixing member 1, and can maintain a basic constant force state.

[0057] The magnetic field distributions of the first to fourth permanent magnet surfaces are as Figure 5 shown. The N poles of the two first magnet assemblies (21, 22) are close to the S poles of the two second magnet assemblies arranged on the second permanent magnet surface 6, and there is an air gap of 0.1 mm. The S poles of the two fourth magnet assemblies (31, 32) are close to the N poles of the two third magnet assemblies arranged on the third permanent magnet surface 7, and there is an air gap of 0.1 mm.

[0058] As Figure 8As shown, simulation is carried out using the simulation software ANSYS. Except for the positions 5 mm from both ends at the end, the magnetic force changes greatly. Within the entire effective stroke in the middle, a stable end magnetic suction force, that is, the restoring elastic force F, can be maintained between the fixed part 1 and the moving part 5.

[0059] In this embodiment, the edge effect mechanism dominates the restoring elastic force F. When the moving part is moved out of the fixed part, due to magnetic field distortion, the magnetic induction lines at the edge of the end of the magnetic spring bend, resulting in a local magnetic flux density higher than the assumed value of the uniform field. As Figure 7 shown in the force source distribution, during the extraction process, the edge region, especially the part about to break contact, contributes the main magnetic force.

[0060] In this embodiment, different from the magnetic conduction design, two independent permanent magnets are arranged on both sides of the moving part and magnetically attract two independent permanent magnets on the inner wall surface of the stroke groove, doubling the interaction force between the permanent magnets. In addition, the length of the permanent magnet and the structural dimensions of the spring are associated with the magnetic induction intensity. By reasonably setting the end areas of the first magnetic end face and the second magnetic end face, and reasonably setting the lengths and structural dimensions of the first to fourth permanent magnet faces, the power density of the restoring elastic force can be further improved. The magnitude of the restoring elastic force F is related to the end cross-sectional area and the magnetic field strength. The suction force of the permanent magnet can be calculated by the following formula:

[0061]

[0062] Among them, F represents the restoring elastic force, that is, the spring-back suction force, B represents the magnetic induction intensity of the permanent magnet, A represents the areas of the first inner magnetic end face and the second inner magnetic end face, μ0 represents the magnetic permeability in vacuum, g represents the air gap width, w represents the width of the magnet perpendicular to the extraction direction, and k represents the edge effect coefficient.

[0063] A is the end face area, A = w * h, which has nothing to do with the extraction direction and is consistent with the magnetic field direction. For example, if the rectangular first inner magnetic end face or the second inner magnetic end face is cut into a semicircle, that is, the area is reduced, the measured restoring elastic force F will decrease in proportion to the reduction of A.

[0064] Please refer to Figure 10 together. The magnetic induction intensity B can be further improved by reasonably setting the lengths and structural dimensions of the first to fourth permanent magnet faces according to the structural dimensions of the U-shaped magnetic spring device, as well as the magnetic induction intensity and the power density of the restoring elastic force. The correction formula is calculated as:

[0065]

[0066] Among them, B r represents the remanence of the permanent magnet; L m represents the length of the magnet; μ rIt represents the relative permeability of the magnet material, dimensionless. For example, the relative permeability of NdFeB is about 1.05, and that of ferrite is about 1.1 - 1.3; g represents the air gap width.

[0067] In addition, the U-shaped magnetic force spring device is also provided with a connection structure. The base 10 of the fixing member 1 includes a machine base connection structure, such as a fixing hole 101. The connecting portion 50 of the moving member 5 includes a counterweight connection structure, such as a connecting hole 506.

[0068] Embodiment 2

[0069] This embodiment relates to a counterweight mechanism, including at least one U-shaped magnetic force spring device in the above embodiments. As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A U-shaped magnetic spring device, characterized in that, It includes a fixed part and a moving part. A first permanent magnet surface and a fourth permanent magnet surface are provided on the fixed part. The first permanent magnet surface and the fourth permanent magnet surface are parallel to each other and a travel slot is formed therebetween. The moving part can move in the travel slot and includes an assembly part. A second permanent magnet surface is provided on the assembly part facing the first permanent magnet surface. The second permanent magnet surface has the opposite magnetic pole (NS pole) to the first permanent magnet surface and has a first magnetic end face. A third permanent magnet surface is provided on the assembly part facing the fourth permanent magnet surface. The third permanent magnet surface has the opposite magnetic pole (NS pole) to the fourth permanent magnet surface and has a second magnetic end face. When the moving part moves relative to the fixed part within the travel range, the first magnetic end face and the second magnetic end face generate a constant end magnetic force with the fixed part and continuously output a restoring force (F) with double power density.

2. The U-shaped magnetic spring device according to claim 1, characterized in that, The first permanent magnet surface and the fourth permanent magnet surface on both sides of the travel slot have the same magnet length as the second permanent magnet surface and the third permanent magnet surface in the middle of the travel slot. The magnet length is half of the travel length set by the U-shaped spring device. The magnet area from the first permanent magnet surface to the fourth permanent magnet surface is proportional to the restoring force.

3. The U-shaped magnetic force spring device according to claim 1, wherein The restoring force F is calculated by the following formula: Wherein, F represents the restoring force, that is, the rebound suction force, B represents the magnetic induction intensity on the magnet surface, A represents the end face area of the first magnetic end face and the second magnetic end face, μ0 represents the magnetic permeability in vacuum, g represents the air gap width, w represents the magnet width perpendicular to the extraction direction dimension, and k represents the edge effect coefficient.

4. The U-shaped magnetic spring device according to claim 3, wherein The magnetic induction intensity is calculated according to the correction formula of the structural dimensions of the U-shaped magnetic force spring device as: Among them, B r represents the remanence of the permanent magnet; L m represents the length of the magnet; μ r represents the relative permeability of the magnet material; g represents the air gap width.

5. The U-shaped magnetic spring device according to claim 2, wherein The first permanent magnet surface is formed by splicing one or more first magnet assemblies in a multi-row and / or multi-column form. The second permanent magnet surface is formed by splicing one or more second magnet assemblies in a multi-row and / or multi-column form. The third permanent magnet surface is formed by splicing one or more third magnet assemblies in a multi-row and / or multi-column form. The fourth permanent magnet surface is formed by splicing one or more fourth magnet assemblies in a multi-row and / or multi-column form.

6. The U-shaped magnetic spring device according to claim 5, characterized in that, The fixed part includes a base and a first fixing plate and a second fixing plate extending from the base. A first assembly step is provided inside the first fixing plate. The first magnet assembly is positioned through the first assembly step and bonded to the first fixing plate with high-strength structural adhesive; a fourth assembly step is provided inside the second fixing plate. The fourth magnet assembly is positioned through the fourth assembly step and bonded to the second fixing plate with high-strength structural adhesive.

7. The U-shaped magnetic spring device according to claim 6, wherein The moving part includes a connecting part. The assembly part is provided below the connecting part. Second assembly steps and third assembly steps are provided on both sides of the assembly part. The second magnet assembly is positioned on the second assembly step and bonded to one side of the assembly part with high-strength structural adhesive; the third magnet assembly is positioned on the third assembly step and bonded to the other side of the assembly part with high-strength structural adhesive.

8. The U-shaped magnetic spring device according to claim 1, characterized in that, The base of the fixed part includes a machine base connection structure, and the connecting part of the moving part includes a counterweight connection structure.

9. The U-shaped magnetic spring device according to claim 1, characterized in that, An air gap is provided between the first permanent magnetic surface and the facing second permanent magnetic surface, and an air gap is provided between the fourth permanent magnetic surface and the facing third permanent magnetic surface. The range of the width of the air gap is 0.1 mm to 0.3 mm.

10. A counterweight mechanism, characterized in that, The U-shaped magnetic spring device according to any one of claims 1-9 is adopted.

Images