JPH081233B2 - Vibration damping device - Google Patents

Description

The present invention relates to a vibration damping device characterized by skillfully combining a magnet body and a magnetic fluid, and more specifically, a combination of the magnet body and the magnetic fluid. The present invention relates to a vibration damping device that utilizes the phenomenon of increase in apparent viscosity due to the magnetic field of the magnetic fluid that is caused in 1.

Conventionally, there are various types of vibration damping devices such as a spring mechanism. However, in the conventional damping device, the elastic mechanism portion in each device is made as soft as possible in addition to the demand for further enhancing the vibration damping effect, so that the vibration to be dampened is kept long in the elastic mechanism portion itself. There was a defect that they were connected and, as a result, the efficiency of vibration damping was lowered. In addition, in various conventional damping devices, it is general that the vibration source and the damping mechanism in the device are in contact with each other. The problem was that it was transmitted to the mechanical part itself, which was used as a vibration suppressor, and that it itself acted as a vibration medium.

Thus, conventionally, it has been a very important issue to improve the vibration damping ratio while eliminating the defects and the like.

The present invention was developed in view of the conventional situation as described above, and its purpose is to eliminate the above-mentioned conventional defects and inconveniences, and to promptly and efficiently attenuate various induced vibrations. At the same time, it is to provide a device having a very good vibration damping ratio.

An embodiment of the present invention will be described below with reference to the accompanying drawings.

In the present invention, the mechanism itself is not limited to this, but as shown in the figure, when the mechanism of the device is, for example, of the piston type, the magnet body is provided inside the outer cylinder part 1 made of a non-ferrous material. The inner cylindrical portion 2 made of the same is housed, and the passage portion 3 having an appropriate gap is formed between the outer peripheral surface of the inner cylindrical portion 2 and the inner peripheral surface of the outer cylindrical portion 1. Magnetic fluid 4
Has been delivered. The upper surface of the inner cylinder portion 2 is fixed to the inner cylinder portion support shaft portion 5 made of a non-ferrous material, and the inner cylinder portion support shaft portion 5 is fixed.
Above the above, through an appropriate flat plate portion 6, for example, as an application example of the present device, when the present device is used as a vibration isolation frame as described later, an upper frame A of equipment or the like is appropriately arranged, and A lower stand B is arranged on the lower surface of the outer cylinder part 1.

As shown in the illustrated example, the structure of the magnet body constituting the inner cylinder portion 2 is such that a plurality of magnet bodies 11 are laminated via a spacer 12 made of a non-magnetic material such as acrylic, and each magnet body 11 is a spacer. They are connected and fixed with 12 poles facing each other. Thus, the inner cylinder portion 2 formed in such a state induces a magnetic field in the following state on the outer peripheral side surface thereof. That is, since the magnet bodies 11 are arranged in series so that they have the same poles facing each other, each magnetic field 13 is generated as shown by the broken line in the figure, and the maximum and strong magnetic field 14 (in the figure) is generated at each intervening spacer 12. Black spots), and the magnetic field is minimum at the center of each magnet body 11. In this case, although not particularly shown, when the magnet bodies 11 are opposed to each other with different polarities, an extremely large magnetic field can be obtained at the upper and lower ends of the inner cylinder portion 2 made of the magnet body, but the outer circumference of the inner cylinder portion is large. On the side, the magnetic field will be very small. In the present invention, the arrangement combination of the magnet bodies 11 forming the inner cylinder portion 2 is
Of course, various types can be considered, and the present invention is not limited to the illustrated example.

Thus, in the device according to the present invention, the inner peripheral surface of the outer cylindrical portion 1 and the outer peripheral surface of the inner cylindrical portion 2 are prevented while avoiding the extreme nonuniformity of the magnetic field due to the continuous arrangement of the magnet bodies 11. It is possible to very effectively apply a magnetic field 14 to the magnetic fluid 4 flowing through the narrow passage portion 3 formed between the
The apparent viscosity of the magnetic fluid 4 can be further increased. The apparent viscosity of the magnetic fluid 4 can be easily adjusted by concentrating or diluting the magnetic fluid 4 itself and changing the viscosity concentration of the magnetic fluid.

As described above, for example, the present device configured by the piston system is configured such that the magnetic fluid 4 is moved as the inner cylinder 2 moves up and down.
Flows through the narrow passage portion 3 with a velocity gradient, so that a pressure difference is generated between the upper surface and the lower surface of the inner cylindrical portion 2 in proportion to the average velocity of the flow, and as a result, a braking force is generated. In addition, the braking force is further increased, and the free vibration induced by utilizing this braking force can be quickly attenuated. Further, according to the present invention, by combining the magnetic fluid 4 and each magnet body 11 as described above, the braking force itself depending on the viscosity of the magnetic fluid 4 and the gap of the passage portion 3 is By virtue of the strong magnetic field 14, the apparent viscosity of the magnetic fluid 4 is increased, and a further greater damping effect is added, so that the induced vibration is immediately and efficiently damped. It should be noted that the braking force is the same as that of the magnetic fluid 4 delivered into the outer cylindrical portion 1 as described above.
If the concentration is changed, the adjustment becomes easier, and when a further larger braking force is required, the number of laminated magnet bodies 11 forming the inner cylinder portion 2 is increased or the present apparatus itself is used in parallel. The braking force can be increased by such means.

On the other hand, the present invention has a particularly excellent damping effect as described above, and in addition to disposing the inner cylinder portion 2 composed of the magnet body 11 laminated in the magnetic fluid 4, on the outer peripheral side surface of the inner cylinder portion 2. Due to the strong magnetic field 14 generated, the inner cylindrical portion 2 is always centered without contacting the inner peripheral surface of the outer cylindrical portion 1. Therefore, this device
In other words, it can be regarded as a non-contact type damping mechanism, which completely eliminates the inconvenience that the contacted mechanical parts themselves act as vibration mediators.

One embodiment illustrated here as a mechanism example and an application example of the present apparatus is a case in which the present invention is configured by a piston system and the application is appropriately used as a vibration isolation frame for equipment and the like. Is supported on the lower pedestal B by the spring portion C, and the apparatus is installed between the upper and lower pedestals. Therefore, in the case where the damping device according to the present invention is used for such a vibration isolation mount by, for example, previously obtaining an attenuation constant from the natural period of the vibration isolation base and further adjusting the magnetic fluid 4 to an appropriate concentration, The device itself can quickly attenuate the free vibration induced in either the upper or lower pedestal A or B without acting as any vibration medium.

In addition, it is needless to say that the present device can be used for vibration damping in various fields without being limited to the above-mentioned one application example.

As described above, the present invention, which is characterized by skillfully combining the magnet body and the magnetic fluid, can solve the conventional defects and inconveniences while solving the above-mentioned conventional problems brilliantly. Since there is no contact with each other, there is no wear of each part, so that its service life is extremely long, and in the present invention, no special means for centering the inner cylindrical part is necessary, so that a bearing part is not necessary at all. In addition, the present invention in which a magnetic fluid is delivered into the outer cylinder part eliminates the need for sealing the upper surface of the outer cylinder part at all and has various excellent effects while at the same time, against various random induced vibrations. It is an extremely excellent vibration damping device that can be widely applied.

[Brief description of drawings]

FIG. 1 is a longitudinal side view of an embodiment in which the present invention is configured by a piston type mechanism and one application example of the present invention, FIG. 2 is a front view of the magnet body in FIG. 1, and FIG. FIG. 3 is a schematic side view showing an example in which the present invention uses a vibration-proof frame, and FIG. 3 (B) is a schematic plan view of the same. 1 ... Outer cylinder part, 2 ... Inner cylinder part, 3 ... Passage part, 4 ... Magnetic fluid, 5 ... Inner cylinder part support shaft part, 6 ... Flat plate part, 11 ...
Magnet body, 12 ... spacer, 13 ... magnetic field, 14 ... magnetic field.

Claims (1)

[Claims] 1. A bottomed outer cylinder part made of a non-magnetic material, a magnetic fluid housed in the outer cylinder part, and a plurality of magnet bodies having the same poles facing each other, which are integrally formed in the outer cylinder part. And a magnet body formed as an inner cylindrical portion for receiving a vibration load, which is housed in an arrangement in which an outer peripheral portion forms a passage portion of a magnetic fluid between the outer peripheral portion and an inner wall surface of the outer cylindrical portion, and receives the vibration load. Vibration of the inner cylinder part is attenuated by the viscosity of the magnetic fluid housed in the outer cylinder part and the apparent viscosity of the magnetic fluid in the passage part which is changed by the magnetic field formed in the passage part by each magnet body of the inner cylinder part. A vibration damping device characterized in that