Permanent magnet type full-damping gap magnetic field adjustable magnetorheological damper

Abstract

The permanent magnet type full-damping gap magnetic field adjustable magnetorheological damper comprises a cylinder barrel, a coil groove, an electric coil, a permanent magnet and a wear-resistant magnetic conductive coating, the interior of the cylinder barrel is a cavity, a piston and a piston rod which are connected with each other are arranged in the cylinder barrel, and the cavity in the cylinder barrel is filled with magnetorheological fluid; the coil groove is formed in the inner surface of the cylinder barrel; the electric coil is wound in the coil groove; the permanent magnet is fixed on the inner surface of the cylinder barrel; the wear-resistant magnetic conductive coating is laid on the surface of the permanent magnet, and a damping gap is formed between the wear-resistant magnetic conductive coating and the piston. According to the magnetorheological damper, the permanent magnet and the electric coil are arranged in the cylinder barrel, the magnetic field generated by the permanent magnet and the electric coil can be fully distributed in the whole cavity and the damping gap of the whole damper, the overall length of the magnetic field of the damping gap is adjustable, the maximum damping force of the magnetorheological damper is increased, agglomeration and sedimentation of magnetorheological fluid can be relieved, and the damping effect of the magnetorheological damper is improved. And the long-term stability of the mechanical property of the magnetorheological damper is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of magnetorheological dampers, and in particular relates to a permanent magnet type magnetorheological damper with full damping gap and adjustable magnetic field. Background Art

[0002] Magnetorheological dampers have the characteristics of millisecond response speed, continuously adjustable damping force, and intelligent control, and have become excellent semi-active control devices in the engineering field. At present, magnetorheological dampers have been widely used in vibration reduction and anti-seismic systems of buildings and bridges, vibration reduction of railway locomotives and vehicles, and suspension systems of automobiles.

[0003] Magnetorheological damper is a semi-active control device that uses magnetorheological fluid to achieve liquid-solid two-phase inversion characteristics in a short time (milliseconds) under the action of a magnetic field. Magnetorheological fluid is a suspension formed by micron- or nano-sized ferromagnetic particles immersed in a non-magnetic carrier fluid, with a small amount of other additives. In the absence of a magnetic field, the magnetorheological fluid exhibits the characteristics of a low-viscosity Newtonian fluid; in the presence of a magnetic field, the magnetorheological fluid exhibits a high-viscosity, low-fluidity Bingham fluid, and the viscosity of the liquid has a corresponding relationship with the magnetic flux. Since the ferromagnetic particles in the magnetorheological fluid are very small and the density difference between them and the non-magnetic carrier fluid is very large, the ferromagnetic particles in the magnetorheological fluid are prone to agglomeration and sedimentation, and this problem has not been effectively solved for a long time, which has greatly limited the promotion and use of magnetorheological dampers.

[0004] In addition, according to the Bingham plate model, the maximum damping force of the magnetorheological damper is proportional to the effective length of the damping gap. Therefore, the longer the effective damping gap of the magnetorheological damper, the better. However, the traditional shear valve magnetorheological damper has a groove on the piston, and the electric coil is wound in the groove. Due to the limitations of the wire diameter and the number of turns in the electric coil, the groove usually occupies about 50% of the total length of the piston. Since the damping gap of the groove part of the winding electric coil has no magnetic field, it is an invalid length, which not only increases the volume and weight of the damper, but also reduces the maximum damping force of the magnetorheological damper. The maximum damping force loss is about 50%. Summary of the invention

[0005] In order to solve the above problems, the present invention proposes a permanent magnet full damping gap magnetorheological damper with adjustable magnetic field.

[0006] The permanent magnet full damping gap magnetic field adjustable magnetorheological damper of the present invention comprises a cylinder, an electric coil and a permanent magnet, the interior of the cylinder is a cavity, a piston and a piston rod connected to each other are arranged in the cylinder, and the cylinder cavity is filled with magnetorheological fluid; it is characterized in that a coil groove is arranged on the inner surface of the cylinder, the electric coil is wound in the coil groove, the permanent magnet is fixed on the inner surface of the cylinder, the surface of the permanent magnet is paved with a wear-resistant magnetic conductive coating, and a damping gap is formed between the wear-resistant magnetic conductive coating and the piston.

[0007] The cylinder is a hollow cylindrical cylinder, with cylinder cover plates fixed at both ends of the cylinder, the piston is a hollow cylindrical piston, the piston rod is a cylindrical piston rod, the piston rod passes through the piston from the center of the piston, and both ends pass through the center of the cylinder cover plate, and the central axes of the piston rod, piston, cylinder and cylinder cover plate coincide.

[0008] The magnetorheological fluid is filled in the cavity and the damping gap inside the cylinder.

[0009] The coil grooves include annular grooves located on the inner surfaces of both ends of the cylinder and multiple strip grooves located on the inner surface of the cylinder and arranged along the length direction of the cylinder. The multiple strip grooves are connected to the annular grooves at both ends, and the multiple strip grooves are parallel to each other and arranged at intervals.

[0010] The permanent magnet is a long strip permanent magnet with a fan-shaped cross section, and both ends of the permanent magnet are in contact with the inner surface of the cylinder cover plate.

[0011] The numbers of the strip grooves, electric coils and permanent magnets are all even numbers, and the cross-sections of the permanent magnet ring composed of multiple permanent magnets and the coil ring composed of multiple electric coils are both axisymmetric shapes.

[0012] The inner and outer magnetic poles of two adjacent permanent magnets in the permanent magnets are opposite to each other, and the magnetic field generated by the permanent magnets covers the entire damping gap.

[0013] The magnetic field generated by the electric coil after being energized covers the entire damping gap, and the magnetic field generated by the electric coil after being energized and the magnetic field generated by the permanent magnet are superimposed on or offset each other.

[0014] The beneficial effects of the present invention are as follows: the electric coil of the magnetorheological damper of the present invention is arranged in the coil groove of the cylinder, so that the diameter and number of turns of the wire in the electric coil are not limited by the diameter and length of the piston, the volume and weight of the magnetorheological damper are reduced, and the maximum damping force of the magnetorheological damper is increased; the magnetic field generated by the permanent magnet can always cover the entire cavity and damping gap of the damper, and the magnetorheological fluid can maintain a semi-solid state without flow under the action of the magnetic field, so the magnetic particles of the magnetorheological fluid do not agglomerate and settle, thereby ensuring the long-term stability of the mechanical properties of the magnetorheological damper; both the permanent magnet and the electric coil can generate a magnetic field in the entire cavity and damping gap of the damper, and the magnetic field generated by the electric coil can be superimposed on or offset by the magnetic field generated by the permanent magnet. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a longitudinal cross-sectional view of the position of the electric coil of the permanent magnet type full damping gap magnetic field adjustable magnetorheological damper of the present invention.

[0016] Figure 2 It is a longitudinal cross-sectional view of the position of the non-electric coil of the permanent magnet type full damping gap magnetic field adjustable magnetorheological damper of the present invention.

[0017] Figure 3 yes Figure 1 AA section view.

[0018] Figure 4 yes Figure 1 BB section view.

[0019] Figure 5 yes Figure 1 Schematic diagram of the magnetic circuit structure at the BB section position.

[0020] Reference numerals:

[0021] Piston rod 1; piston 2; damping gap 3; cylinder 4; strip groove 41; annular groove 42; permanent magnet 5; magnetic field 51 of permanent magnet; wear-resistant magnetic conductive coating 6; electric coil 7; magnetic field 71 after the coil is energized; cylinder cover plate 8; magnetorheological fluid 9. DETAILED DESCRIPTION

[0022] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0023] like Figure 1-Figure 5As shown, the permanent magnet full damping gap magnetic field adjustable magnetorheological damper of the present invention comprises: a cylinder 4, a coil groove, an electric coil 7, a permanent magnet 5 and a wear-resistant magnetic conductive coating 6. The interior of the cylinder 4 is a cavity, and a piston 2 and a piston rod 1 connected to each other are arranged in the cylinder 4, and the cylinder 4 is filled with a magnetorheological fluid 9; the coil groove is arranged on the inner surface of the cylinder 4; the electric coil 7 is wound in the coil groove, which can reduce the volume and weight of the magnetorheological damper and increase the maximum damping force of the magnetorheological damper; the permanent magnet 5 is fixed on the inner surface of the cylinder 4; the wear-resistant magnetic conductive coating 6 is laid on the surface of the permanent magnet 5, and a damping gap 3 is formed between the wear-resistant magnetic conductive coating 6 and the piston 2. The magnetorheological fluid 9 is filled in the cavity and the damping gap 3 inside the cylinder 4. The cross section of the damping gap 3 is annular, and the length of the damping gap 3 is consistent with the length of the piston 2.

[0024] The cylinder 4 is a hollow cylindrical cylinder, and cylinder cover plates 8 are fixed at both ends of the cylinder 4. The piston 2 is a hollow cylindrical piston, and the piston rod 1 is a cylindrical piston rod. The piston rod 1 passes through the piston from the center of the piston 2, and both ends pass through the center of the cylinder cover plate 8. The central axis of the piston rod 1, the piston 2, the cylinder 4 and the cylinder cover plate 8 coincide. The setting of the hollow piston can reduce the weight of the magnetorheological damper. The piston 2 and the piston rod 1 can be an integrally formed structure, and the piston rod 2 can drive the piston to move in the cylinder.

[0025] The coil groove includes an annular groove 42 located on the inner surface of both ends of the cylinder 4 and a plurality of strip grooves 41 located on the inner surface of the cylinder 4 and arranged along the length direction of the cylinder. The plurality of strip grooves 41 are connected to the annular grooves 42 at both ends, and the plurality of strip grooves 41 are parallel to each other and arranged at intervals. The coil groove is used to place the electric coil 7, so the electric coil 7 is arranged at intervals along the inner surface of the cylinder 4. The permanent magnet 5 is arranged inside the electric coil 7, that is, the permanent magnet 5 is connected to the electric coil 7 and the inner surface of the cylinder 4.

[0026] The permanent magnet 5 is a long strip permanent magnet with a sector-shaped cross section, and both ends of the permanent magnet 5 are in contact with the inner surface of the cylinder cover plate 8. A plurality of permanent magnets 5 form a ring shape.

[0027] The numbers of the strip grooves, the electric coils 7 and the permanent magnets 5 are all even numbers, and the cross-sections of the permanent magnet ring composed of the plurality of permanent magnets 5 and the coil ring composed of the plurality of electric coils 7 are both axisymmetric shapes.

[0028] like Figure 5 As shown, the inner and outer magnetic poles of two adjacent permanent magnets 5 among the permanent magnets 5 are opposite, and the magnetic field generated by the permanent magnets 5 covers the entire damping gap.

[0029] The magnetic field generated by the electric coil 7 after being energized covers the entire damping gap 3 , and the magnetic field generated by the electric coil 7 after being energized and the magnetic field generated by the permanent magnet 5 are superimposed on or offset each other.

[0030] When the magnetic field of the electric coil 7 is in the same direction as the magnetic field of the permanent magnet 5, the magnetic field of the magnetorheological damper will be strengthened, and when the magnetic field of the electric coil 7 is in the opposite direction to the magnetic field of the permanent magnet 5, the magnetic field of the magnetorheological damper will gradually weaken. The direction of the current in the electric coil 7 determines the direction of the magnetic field of the electric coil 7, thereby achieving adjustable magnetic field of the damping gap 3.

[0031] When subjected to external vibration, the electric coil 7 is energized, and the magnetic field of the electric coil 7 is aligned with the magnetic field direction of the permanent magnet 5, thereby enhancing the total magnetic field of the magnetorheological damper, and increasing the viscosity of the magnetorheological fluid 9 in the cylinder 4, thereby increasing the damping force of the magnetorheological damper. Therefore, the damping force of the magnetorheological damper can be adjusted by adjusting the magnitude and direction of the current in the electric coil 7.

[0032] When the piston rod 1 drives the piston 2 to move left and right in the cylinder 4 along the axial direction, the magnetorheological fluid 9 in the left and right cavities can flow back and forth in the left and right cavities through the damping gap 3, thereby generating a damping force. The magnitude of the damping force is related to the magnetic field strength. The greater the magnetic field strength, the greater the shear yield strength of the magnetorheological fluid, and the greater the damping force of the damper. The flow direction of the magnetorheological fluid 9 in the cylinder 4 is perpendicular to the direction of the magnetic field, so the shear yield strength of the magnetorheological fluid can be effectively changed, and the full length of the damping gap 3 is effective, which maximizes the maximum output of the magnetorheological damper and reduces the volume and mass of the magnetorheological damper.

[0033] In the description of the present invention, it is necessary to understand that the terms "center", "length", "width", "thickness", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply 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 understood as a limitation on the present invention.

[0034] In addition, in the description of the present invention, “plurality” means at least two, for example, two, three, etc., unless otherwise clearly and specifically defined.

[0035] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0036] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0037] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0038] Although the above embodiments have been shown and described, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those of ordinary skill in the art are all within the scope of protection of the present invention.

Claims

1. A permanent magnet full damping gap magnetic field adjustable magnetorheological damper, comprising a cylinder, an electric coil and a permanent magnet, wherein the interior of the cylinder is a cavity, a piston and a piston rod connected to each other are arranged in the cylinder, and the cylinder cavity is filled with magnetorheological fluid; characterized in that: The inner surface of the cylinder is provided with a coil groove, the electric coil is wound in the coil groove, the permanent magnet is fixed on the inner surface of the cylinder, the surface of the permanent magnet is paved with a wear-resistant magnetic conductive coating, and a damping gap is formed between the wear-resistant magnetic conductive coating and the piston.

2. The permanent magnet full damping gap magnetic field adjustable magnetorheological damper according to claim 1 is characterized in that: The cylinder is a hollow cylindrical cylinder, with cylinder cover plates fixed at both ends of the cylinder, the piston is a hollow cylindrical piston, the piston rod is a cylindrical piston rod, the piston rod passes through the piston from the center of the piston, and both ends pass through the center of the cylinder cover plate, and the central axes of the piston rod, piston, cylinder and cylinder cover plate coincide.

3. The permanent magnet full damping gap magnetic field adjustable magnetorheological damper according to claim 1 is characterized in that: The magnetorheological fluid is filled in the cavity and the damping gap inside the cylinder.

4. The permanent magnet full damping gap magnetic field adjustable magnetorheological damper according to claim 1, characterized in that: The coil grooves include annular grooves located on the inner surfaces of both ends of the cylinder and multiple strip grooves located on the inner surface of the cylinder and arranged along the length direction of the cylinder. The multiple strip grooves are connected to the annular grooves at both ends, and the multiple strip grooves are parallel to each other and arranged at intervals.

5. The permanent magnet full damping gap magnetic field adjustable magnetorheological damper according to claim 4 is characterized in that: The permanent magnet is a long strip permanent magnet with a fan-shaped cross section, and both ends of the permanent magnet are in contact with the inner surface of the cylinder cover plate.

6. The permanent magnet full damping gap magnetic field adjustable magnetorheological damper according to claim 5, characterized in that: The numbers of the strip grooves, the electric coils and the permanent magnets are equal and are all even numbers, and the cross-sections of the permanent magnet ring composed of multiple permanent magnets and the coil ring composed of multiple electric coils are both axisymmetric shapes.

7. The permanent magnet full damping gap magnetic field adjustable magnetorheological damper according to claim 6, characterized in that: The inner and outer magnetic poles of two adjacent permanent magnets in the permanent magnets are opposite, and the permanent magnetic field generated by the permanent magnets can cover the entire damping gap and the cavity between the inner side of the cylinder cover plate and the outer side of the piston.

8. The permanent magnet full damping gap magnetic field adjustable magnetorheological damper according to claim 1, characterized in that: The magnetic field generated by the electric coil after being energized can cover the entire damping gap and the cavity between the inner side of the cylinder cover plate and the outer side of the piston, and the magnetic field generated by the electric coil after being energized and the permanent magnetic field generated by the permanent magnet can overlap or offset each other, thereby achieving adjustable magnetic field of the entire damping gap.

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