CN106678255A - First-order buoyancy magnetic liquid damping vibration absorber for magnetic shielding - Google Patents

Abstract

The utility model relates to a first-order buoyancy magnetic liquid damping shock absorber with magnetic shielding, which belongs to the field of mechanical engineering vibration. It successfully solves the problem that the existing magnetic liquid damping shock absorber cannot be applied in engineering practice due to various structural problems. The device includes a shell (1), an upper shield (2), an upper permanent magnet (3), a mass (4), a lower permanent magnet (5), a lower shield (6) and a magnetic liquid (7). When the outside vibrates, the mass block (4) moves in the upper and lower shields, and the magnetic liquid (7) flows in the gap between the upper and lower permanent magnets and the mass block (4), thereby absorbing energy to achieve the purpose of vibration reduction, and the upper magnet The first-order buoyancy formed by (3) and the lower permanent magnet (5) inside the magnetic fluid (7) makes a frequency difference between the mass block (4) and the housing (1), maximizing the vibration damping efficiency.

Description

A magnetically shielded first-order buoyancy magnetic liquid damping shock absorber

technical field

The invention belongs to the field of mechanical engineering vibration.

Background technique

The magnetic liquid damping shock absorber is a passive shock absorber with high sensitivity to inertial force, and has the advantages of simple structure, small size, large energy consumption and long life. Due to the special operating environment of the spacecraft, its own volume, weight and energy carried are limited to a certain extent, so the magnetic liquid damping shock absorber is very suitable for the low-frequency, small-amplitude vibration reduction of long straight objects in large spacecraft, such as The solar panels and antennas of the space station also have broad application prospects on the ground, such as the vibration reduction of high-power antennas up to 100 meters long, the vibration reduction of precision balances, and so on. However, the existing magnetic liquid damping shock absorbers cannot be applied in engineering practice due to various structural problems. The specific problems are as follows:

Now the most common magnetic liquid damping shock absorber mainly adopts the second-order buoyancy principle of magnetic liquid, as described in reference 1 (patent application for publication number CN102032304A), reference 2 (patent application for publication number CN104074903A), comparison Described in document 3 (patent application with publication number CN102042359A), described in comparative document 4 (publication number CN102494070A), described in comparative document 5 (publication number JP11-230255A) and described in comparative document 6 (publication number CN103122965A), a few adopt The principle of the first-order buoyancy of magnetic liquids, as described in reference 7 (patent application with publication number JP11-223247A).

The shock absorber device described in comparative document 1 (the patent application with the publication number of CN102032304A), the shock absorber includes a non-magnetic shell, a magnetic liquid, a permanent magnet, nuts, end caps, bolts, screws, gaskets and O-shaped sealing ring. The patent application uses a cylindrical permanent magnet as a mass, and fills the non-magnetic shell with magnetic liquid, so that the mass is suspended in the shell by using the second-order buoyancy principle of the magnetic liquid. When the outside vibrates, the relative motion between the mass block and the shell causes the magnetic fluid to flow in the gap between the mass block and the shell, resulting in viscous loss. However, the shock absorber described in this patent utilizes the second-order buoyancy principle of magnetic liquid, and the mass block must be a permanent magnet, so there are the following deficiencies in practical application: first, the magnetic field at both ends of the permanent magnet is very strong, and the magnetic The viscosity of the liquid will increase sharply under the action of the magnetic field, so the flow of the magnetic liquid between the permanent magnet and the shell will be very difficult, so it is not sensitive to the inertial force and the vibration damping effect is poor; second, the material of the permanent magnet is usually It is relatively brittle. When the spacecraft is launched into space, the acceleration is extremely high, which can easily cause the collision between the permanent magnet and the shell, and eventually cause the permanent magnet to break, thereby causing the shock absorber to fail, so it is not practical.

The shock absorber device described in comparative document 2 (patent application with publication number CN104074903A), the shock absorber includes a non-magnetic shell, bolts, nuts, permanent magnets, magnetic liquid, non-magnetic shell, O-rings, air holes , annular gap, etc. The patent application also uses the permanent magnet as a mass block, and absorbs a small amount of magnetic liquid at both ends of the permanent magnet. The second-order buoyancy principle of the magnetic liquid is used to make the permanent magnet suspend. The inner wall of the shell is processed into an arc shape to make the magnetic liquid generate elastic force. , so that the permanent magnet is always in the center of the shell, but when the permanent magnet moves along the arc-shaped surface, since the bottom surface of the permanent magnet is a plane, it is easy to rub against the arc-shaped inner wall of the shell, and when the acceleration is extremely high, it is easy to appear The permanent magnet fragmentation problem caused by the collision between the permanent magnet and the housing is not practical.

The shock absorber device described in comparative document 3 (the patent application with the publication number of CN102042359A), the shock absorber is similar to the device structure described in comparative document 1, but comparative document 3 has 4 to 8 through magnets processed on the permanent magnet. The through hole can make the magnetic fluid flow more smoothly and increase the friction area. However, since the magnetic field at both ends of the permanent magnet is very strong, both the magnetic liquid in the through hole and the magnetic liquid between the permanent magnet and the housing will not flow normally due to excessive viscosity. The effect is not obvious; secondly, because the through holes are processed on the permanent magnets, the fragility of the permanent magnets is increased. When the acceleration is extremely high, the permanent magnet fragmentation problem caused by the collision between the permanent magnets and the shell will be more serious. Prominently, meanwhile, cylindrical permanent magnets produce a weaker magnetic field on the sides and thus provide insufficient centering force to be practical.

For the shock absorber device described in comparative document 4 (patent application with publication number CN102494070A), the principle of the shock absorber is similar to that of the device described in comparative document 1, but the device described in this patent processes the shell into a hollow spherical shape, and the permanent magnet Process into solid balls. However, the simple shape change cannot solve the problem of permanent magnet fragmentation and difficulty of magnetic fluid flowing between the permanent magnet and the housing, and thus is not practical.

Compared with the shock absorber described in Document 5 (patent application with Publication No. JP11-230255A), the shock absorber is a shock absorber for shaft vibration, which uses the second-order buoyancy principle of magnetic liquid and uses permanent magnets as A rotating mass. Although this patent installs a ceramic ring 5 on the wall of the housing to avoid the direct collision between the permanent magnet and the housing, because the brittleness of ceramics is much greater than that of the permanent magnet, when a collision occurs, the ceramic ring 5 is extremely fragile, thereby reducing pollution. The internal cavity of the vibrator reduces the vibration damping effect. At the same time, this patent cannot solve the problem that the magnetic liquid is difficult to flow between the permanent magnet and the housing, so it is not practical.

Compared with the shock absorber device described in document 6 (patent application with publication number CN103122965A), the shock absorber is a shock absorber for reducing the vibration of solar sail panels, which utilizes the second-order buoyancy principle of magnetic liquid, and the mass The block is an annular permanent magnet. This patent maintains the central position of the permanent magnet by using a gasket with a tapered angle, and prevents the second annular permanent magnet as a mass from hitting the wall by bonding the first annular permanent magnet magnetized in the radial direction on the inner wall of the housing. , the first annular permanent magnet is opposite to the second annular permanent magnet with the same pole. When the spacecraft is launched, the acceleration is extremely large, sometimes exceeding 10 gravitational accelerations, the smaller the distance between the first annular permanent magnet and the second annular permanent magnet, the greater the repulsive force, which can effectively prevent the second annular permanent magnet from moving along the radial direction. wall-crashing behavior. However, since the repulsive force between the permanent magnets is an unbalanced force, the second annular permanent magnet will also be subjected to a moment along the axial direction while being subjected to a repulsive force along the radial direction, so during the launch of the spacecraft, the moment is very large. It is easy to cause the second annular permanent magnet to collide with the end cover or the bottom surface of the casing, and eventually cause the second annular permanent magnet to be broken, which is not practical.

Compared with the shock absorber device described in Document 7 (patent application with publication number JP11-223247A), the shock absorber is a shock absorber for reducing the vibration of the rotating shaft, which utilizes the first-order buoyancy principle of the magnetic liquid, and the mass The block is a ring-shaped non-magnetic material, and a circle of permanent magnets is installed on the rotating shaft so that the mass block does not shift in the circumferential direction. However, based on the principle of first-order buoyancy of magnetic liquid, it can be known that a single set of permanent magnets is unstable for suspending non-magnetic materials, and it is easy to cause the mass block to shift and disturb in the axial direction of the rotating shaft. Therefore, this patent does not Has practical value.

Compared with the shock absorber device described in Document 8 (patent application with publication number CN104879412A), the shock absorber forms a first-order buoyancy force in a container filled with magnetic liquid by using the magnetic field formed by two permanent magnets with opposite polarities. , a spherical mass is suspended inside the container, and a magnetic shield is installed on the outside for magnetic shielding. However, relying only on the magnetic field formed by two purely opposite permanent magnets with the same poles, no effective radial force can be formed inside the magnetic liquid, making the mass block extremely easy to deflect. At the same time, the magnetic liquid of the shock absorber must be filled with the container, causing the mass of the entire shock absorber to increase.

Therefore, it is urgent to redesign and improve the structure of the magnetic liquid damping shock absorber so that it can be applied in practical engineering.

Contents of the invention

The technical problem to be solved by the present invention is that the current magnetic liquid damping shock absorber has difficulty in the flow of the magnetic liquid due to various structural defects, the permanent magnet is easily broken, the centering effect is not good, the viscous energy consumption efficiency is not high, and the quality is large And other problems, making it impossible to be applied in engineering practice. A magnetically shielded first-order buoyancy magnetic liquid damping shock absorber is specially provided.

The technical solution adopted by the present invention to solve its technical problems is:

The shock absorber includes a shell, an upper shield, an upper permanent magnet, a quality block, a lower permanent magnet, a lower shield and magnetic liquid.

The upper shield is an inverted "concave" shape structure, the upper surface of the upper permanent magnet is installed in the groove of the upper shield and fixedly connected; the lower shield is an upright "concave" shape structure, the lower surface of the lower permanent magnet is installed in the groove of the lower shielding case, and fixedly connected. The lower surface of the upper permanent magnet and the upper surface of the lower permanent magnet are respectively injected with magnetic liquid.

Both the upper shield and the lower shield are made of magnetically permeable materials, and their external dimensions are identical; the external dimensions of the upper permanent magnet and the lower permanent magnet are identical; The shape of the groove is the same as that of the lower shield, but the size is smaller than the groove size of the upper shield and the lower shield, which is a clearance fit.

The thickness of the upper permanent magnet and the lower permanent magnet is smaller than the depth of the grooves of the upper shielding case and the lower shielding case. In this way, the upper and lower permanent magnets can respectively form magnetic circuits in the upper and lower shields. At the same time, the magnetic liquid can respectively form a tapered magnetic liquid layer between the groove bosses of the upper and lower shields and the upper and lower permanent magnets. This magnetic liquid layer will generate a strong body force pointing to the origin, so it can ensure that the masses are suspended in the grooves of the upper shield and the lower shield. This invention is different from the purpose of the first annular permanent magnet and the second annular permanent magnet opposite to each other in order to prevent the second annular permanent magnet from hitting the wall in the prior art (device described in reference 6), and also avoids the existing The technology (the device described in reference 7) increases the disturbance problem caused by the unstable centering of the mass produced by installing permanent magnets on the rotating shaft. It also avoids the problem that the prior art (the device described in Reference 8) cannot form an effective radial force inside the magnetic liquid, making the mass block extremely easy to deflect. In addition, this method will make the magnetic liquid no longer need to fill the shell, so that the quality of the shock absorber is greatly reduced, thereby completely solving the problem of the existing technology (the devices described in references 1, 3, 4 and 5) ) in the case where the permanent magnet is placed inside the casing, the injection of the magnetic liquid is difficult or even impossible to fill.

The casing is a thin-walled cavity structure, and the upper surface of the upper shielding cover equipped with the upper permanent magnet is installed on the upper surface of the inner cavity of the casing. The lower surface of the lower shielding case equipped with the lower permanent magnet is installed on the lower surface of the housing cavity. The shell material can be non-magnetic material or magnetic material.

Put the mass into the housing so that the mass is suspended between the upper permanent magnet and the lower permanent magnet.

The outer shape of the mass block is the same as the outer shape of the grooves of the upper shield and the lower shield, but the size is smaller than the groove size of the upper shield and the lower shield. The gap between the mass and the upper shield and the gap between the mass and the lower shield should be larger than the vibration amplitude. The mass block can be in any shape, preferably cylindrical or polygonal, and the material is a non-magnetic material. The material of the mass block is a non-magnetic material, which can completely solve the magnetic viscosity effect caused when the mass block is a permanent magnet in the prior art (the devices described in Documents 1, 3, 4, and 5), resulting in a problem between the mass block and the shell. The problem of difficult flow of magnetic fluid between. In the present invention, since the mass block is a non-magnetic material, it can choose a material whose hardness is much smaller than that of the shell material, such as solid wood, aluminum, titanium, gold, silver, and copper. It only deforms without breaking, and still maintains a good damping effect. When used on the ground, the mass block is made of a material with a density greater than that of the selected magnetic liquid, so that it can be better centered. When used in space, there is no requirement for the density of the mass block.

Compared with the prior art, the present invention has the beneficial effects: (1) the structure of the upper and lower shields makes it unnecessary to fill up the magnetic liquid, so that the quality of the shock absorber is greatly reduced; (2) the upper and lower end covers The material is a material with excellent magnetic permeability, and the upper and lower permanent magnets make the magnetic liquid form a liquid layer with a tapered surface, which greatly improves the centering effect of the mass block; (3) due to the upper and lower permanent magnets Magnetic circuits can be formed in the upper and lower shields respectively, so there is no need to have special requirements for the installation direction of the upper and lower permanent magnet poles, and the housing does not need to be made of magnetically permeable materials; (4) The shape of the mass block can be changed Diversification; (5) The mass blocks are made of non-magnetic materials, so materials with lower hardness and greater plasticity can be selected, which can effectively solve the problem of mass block fragmentation after hitting the wall, and also avoid the damage caused by the magnetic viscous effect. Mobility problems.

Description of drawings

Fig. 1 A magnetically shielded first-order buoyancy magnetic liquid damping shock absorber.

In FIG. 1 : a housing 1 , an upper shield 2 , an upper permanent magnet 3 , a mass 4 , a lower permanent magnet 5 , a lower shield 6 and a magnetic liquid 7 .

detailed description

The present invention will be further described with accompanying drawing as specific embodiment:

A magnetic liquid shock absorber based on the first-order buoyancy principle of a double cone angle, as shown in Figure 1, the shock absorber includes: a housing 1, an upper shield 2, an upper permanent magnet 3, a mass 4, a lower permanent magnet 5, a lower Shield 6 and magnetic fluid 7.

Connections between the parts making up the device:

The upper shield 2 is an inverted "concave" structure, and the upper surface of the upper permanent magnet 3 is installed in the groove of the upper shield 2 and fixedly connected. The lower shield 6 is an upright "concave" shape structure, and the lower surface of the lower permanent magnet 5 is installed in the groove of the lower shield 6 and fixedly connected.

The housing 1 is a thin-walled cavity structure, and the upper surface of the upper shield 2 equipped with the upper permanent magnet 3 is installed on the upper surface of the inner cavity of the housing 1 . The lower surface of the lower shield 6 equipped with the lower permanent magnet 5 is installed on the lower surface of the inner cavity of the housing 1 .

The lower surface of the upper permanent magnet 3 and the upper surface of the lower permanent magnet 5 are respectively injected with magnetic liquid 7 .

The mass block 4 is put into the housing 1 , so that the mass block 4 is suspended between the upper permanent magnet 3 and the lower permanent magnet 5 .

Claims (4)

1. A magnetically shielded first-order buoyancy magnetic liquid damping shock absorber is characterized in that: it comprises a housing (1), an upper shield (2), an upper permanent magnet (3), a mass (4), and a lower permanent magnet. magnet (5), lower shielding case (6) and magnetic liquid (7); The upper shield (2) is an inverted "concave" shape structure, the upper surface of the upper permanent magnet (3) is installed in the groove of the upper shield (2), and fixedly connected; the lower shield (6) It is an upright "concave" shape structure, the lower surface of the lower permanent magnet (5) is installed in the groove of the lower shielding cover (6), and fixedly connected; The housing (1) is a thin-walled cavity structure, and the upper surface of the upper shield (2) with the upper permanent magnet (3) is installed on the upper surface of the inner cavity of the housing (1); The lower surface of the lower shield (6) of the lower permanent magnet (5) is installed on the lower surface of the inner cavity of the housing (1); Injecting the lower surface of the upper permanent magnet (3) and the upper surface of the lower permanent magnet (5) into the magnetic liquid (7); The mass block (4) is put into the casing (1), so that the mass block (4) is suspended between the upper permanent magnet (3) and the lower permanent magnet (5). 2. A magnetically shielded first-order buoyancy magnetic liquid damping shock absorber according to claim 1, characterized in that: The upper shielding case (2) and the lower shielding case (6) are both magnetically conductive materials, and the external dimensions are identical; the external dimensions of the upper permanent magnet (3) and the lower permanent magnet (5) are identical; The profile of the permanent magnet (3) and the lower permanent magnet (5) is the same as the groove shape of the upper shield (2) and the lower shield (6), but the size is smaller than that of the upper shield (2) and the lower shield (6) Groove dimensions for a clearance fit. 3. A magnetically shielded first-order buoyancy magnetic liquid damping shock absorber according to claim 1 or 2, characterized in that: The thickness of the upper permanent magnet (3) and the lower permanent magnet (5) is smaller than the depth of the grooves of the upper shielding case (2) and the lower shielding case (6). 4. A magnetically shielded first-order buoyancy magnetic liquid damping shock absorber according to claim 1, characterized in that: The shape of the mass block (4) is the same as the shape of the grooves of the upper shield (2) and the lower shield (6), but the size is smaller than the groove size of the upper shield (2) and the lower shield (6); The gap between the mass block (4) and the upper shielding case (2) and the gap between the mass block (4) and the lower shielding case (6) should be greater than the vibration amplitude.