JPS6137488B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a damper using magnetic fluid.

Dampers are commonly used to cushion excessive shock loads. These are constructed by providing a nozzle 2 at one end of a container body with an opening and a variable internal volume, such as a telescopic and airtight bellows 1 as shown in FIG. When an impact load 3 is applied to the bellows 1, the bellows 1 contracts and the internal working fluid 4, for example air, is discharged through the nozzle 2, and the outflow resistance during this discharge produces a damping effect.

However, in a damper with such a configuration, once the inner diameter of the intake/exhaust nozzle 2 is determined, the damping characteristics are determined, and the characteristics in other areas cannot be obtained.If the inner diameter accuracy is poor, the desired characteristics may not be achieved. There are inconveniences such as not being able to obtain Moreover, when the damping effect is unnecessary, it is not possible to stop or reduce the damping effect at any time.

The present invention has been made to solve the above-mentioned disadvantages, and provides a damper whose damping characteristics can be controlled in various ways by using a magnetic fluid as the working fluid and controlling the magnetic field.

Hereinafter, details of the present invention will be explained with reference to illustrated embodiments. The magnetic fluid described later is a liquid in which colloidal fine powder, such as magnetite, is stably dispersed to prevent the powder from settling or agglomerating due to gravity or magnetic fields, and is essentially a liquid. Although it is a mixture of solid and ferromagnetic liquid, it appears to behave like a ferromagnetic liquid, and its apparent viscosity changes when the external magnetic field is changed. The fine powders include pulverized active magnetic materials such as nickel, cobalt, iron, and other ionic oxides, and the liquids used include water, carbon fluoride, kerosene, and various other materials.

FIG. 2 shows the embodiment shown in FIG. 1, in which an upper bellows 12 and a lower bellows 13 as a container body whose internal volume can be freely changed are connected via a partition plate 11.
are provided, and opposing end surfaces of both bellows 12 and 13 are fixed to a cylindrical partition plate 11.
The outer ends of both bellows 12 and 13 are connected to the upper closing plate 1
4, each is fixedly closed by a lower closing plate 15, and these upper closing plate 14 and lower closing plate 15 are
They are mutually fixed by separate support columns 16. As a result, the total height of the upper bellows 12 and lower bellows 13 is kept constant, and furthermore, both bellows 12, 13
An annular support ring 17 is fitted into the narrow diameter portion to prevent bulging in the radial direction. On the other hand, the partition plate 11 is made of a disc-shaped member, and a boss-shaped nozzle part 18 is provided in the center. A nozzle 19 is provided in the center of the bellows as an opening that penetrates vertically, so that a magnetic fluid 20 serving as a working fluid filled in each bellows 12 and 13 can freely pass therethrough. A coil 21 is provided surrounding the outside of this nozzle 19, which is connected to an electrical device 21a and is adapted to generate a magnetic field in and near the nozzle 19 by passing an electric current through it. Control allows the strength of the magnetic field to be controlled. Note that the coil 21 and the electric device 21a constitute a magnetic field generating device 21b. Bearings 22 fitted to the pillars 16 are disposed on the outer periphery of the partition plate 11, so that the partition plate 1
1 is supported so as to be movable up and down. In addition, three mounting holes are equally spaced on the outside of the partition plate 11, and three connecting columns 24 are fixed to extend in the vertical direction. A plate-shaped actuation receiver 25 is fixed. Further, a return spring 26 made of a compression coil spring is inserted between the partition plate 11 and the lower blocking plate 15, so that the partition plate 11 is constantly pressed by stoppers 27 attached to the columns 16,... ing. On the other hand, the electric device 21a, as schematically shown in FIG. 3, includes a switch 30, a power source 31, a variable resistor 32, an ammeter 3
3 connected in series, both ends of which are connected to both ends of the coil 21, respectively.

Next, the operation of the damper having the above configuration will be explained.

First, the lower blocking plate 15 is fixed, and the present damper is installed and used so that a load is applied to the actuating receiving plate 25, and the damping characteristics are adjusted according to the expected impact load. That is, when the switch 30 is closed and current is applied to the coil 21, a magnetic field is generated within the nozzle 19 and its vicinity. As a result, the apparent viscosity of the magnetic fluid 20 in this portion changes due to the magnetic force. Since the damping characteristics change due to this change in apparent viscosity, the relationship between the current value of the coil 21, the apparent viscosity, the damping characteristics, etc. should be experimentally confirmed in advance, and the variable resistor should be adjusted to obtain the desired damping characteristics. Adjust 32. The preparations are now complete and the operation begins. Thus, when the impact load 35 acts on the actuation receiving plate 25, the actuation receiving plate 25 and the partition plate 11
begin to descend as one. This causes the lower bellows 13 to contract, while the upper bellows 12 to expand. Then, a part of the magnetic fluid 20 is transferred to the nozzle 1
9 and from the lower bellows 13 to the upper bellows 12
move towards. At this time, since it passes through the nozzle 19 with a viscosity set by the magnetic force, a damping effect occurs due to the resistance, and the desired effect is obtained. When the load stops, the spring 26 returns to its initial state. Upon recovery, if the current is stopped, the recovery will occur quickly.
Note that the same effect can be obtained even if the upper bellows 12 is made of a cylindrical member that does not expand or contract.

Next, FIG. 4 shows a second embodiment in which the damper is constructed without using bellows. The upper cylinder 42 is attached to the lower cylinder 41, and the gaskets 43, 43
They are slidably fitted together to form the container body 41a. A ventilation hole 45 is provided in the upper surface 44 of the upper cylinder 42, and a nozzle mounting hole 47 is provided in the center of the lower bottom 46. A nozzle 19 having a coil 21 wound around the outside thereof is inserted and fixed into the nozzle mounting hole 47 . A magnetic fluid 20 is housed inside. Otherwise, the electric device 21 is the same as in the first embodiment.

The operation of the damper of the second embodiment is as follows:
When an impact load is applied to 4 and the upper cylinder 42 descends, the magnetic fluid 20 passes through the nozzle 19 and moves from the lower cylinder 41 to the upper cylinder 42, producing a damping effect, but the effect is the same as in the first embodiment. Therefore, detailed explanation will be omitted.

As detailed above, since the damper of the present invention uses magnetic fluid as the working fluid, by adjusting the strength of the magnetic field, the magnetic flux density flowing in the magnetic fluid is changed, and the magnetic flux generated when entering and exiting the opening is changed. By changing the viscous resistance, desired damping characteristics can be easily obtained from a wide range.
Furthermore, if an electromagnetic coil is used to generate the magnetic field, the damping characteristics can be changed instantaneously. Therefore, when used in vehicles where the number of passengers, cargo, etc. often vary significantly, the damper can always be maintained at its optimum characteristics. Also,
If the damping effect is adjusted to be small in order to speed up the response, even if a sudden shock load is applied, this can be alleviated by rapidly increasing the current. Furthermore, even if the dimensional accuracy of the aperture is poor, desired damping characteristics can be obtained by adjusting the current, so that various effects such as ease of manufacture are achieved.

Although an electromagnetic coil is used as the magnetic field generator in this embodiment, a permanent magnet may also be used. Further, the number of openings may be plural, and the cross-sectional shape may be arbitrarily formed such as an ellipse, polygon, or other irregular shape.

[Brief explanation of the drawing]

Figure 1 is a partially sectional front view showing the main parts of a conventional example;
FIG. 2 is a cutaway front view of the main part of the first embodiment of the present invention, FIG. 3 is a schematic explanatory diagram of the main part, and FIG. 4 is a sectional front view of the second embodiment. 11: Partition plate (partition member), 12: Upper bellows (second member), 13: Lower bellows (first member), 1
9: Nozzle (communication hole), 20: Magnetic fluid, 21:
Coil, 21a: Electric device (power supply device), 21
b: Magnetic field generator, 41: Lower cylinder (first member), 42: Upper cylinder (second member).

Claims (1)

[Claims] 1. A damper characterized by having the following configuration. (a) A first member having a first storage chamber. (b) A second member having at least a continuous portion connected to the first member so as to be movable relative to the first member, and having a second storage chamber. (c) A communication hole is formed in the continuous portion and connects the first storage chamber and the second storage chamber, and moves forward and backward integrally with the second member. A partition member that changes the internal volume of at least the first storage chamber. (d) A magnetic fluid contained in the first storage chamber and the second storage chamber. (e) A magnetic field generating device that generates a magnetic field at a portion of the partition wall member where the continuous holes are formed to control the viscous resistance of the magnetic fluid passing through the communication holes as the second member advances and retreats. 2. The damper according to claim 1, wherein the first member and the second member are expandable bellows. 3. The damper according to claim 1, wherein the first member and the second member are a pair of cylinders that fit into each other. 4. The damper according to claim 1, wherein the magnetic field generating device includes a coil wound around the communication hole and a power feeding device that feeds power to the coil to generate a magnetic field.