JPS6334333B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic fluid damper that is effective for use in engine mounts and the like.

Conventionally, various engine mounts have been proposed in which the spring constant (damping coefficient) can be changed depending on the driving condition. For example, in the engine mount structure shown in FIG. 1, on the engine mount 2 attached to the frame (not shown) through the hole 1,
An engine (not shown) is attached through the hole 3.

Now, in response to vibrations transmitted to the engine mount 2, the fluid in the chamber 4 moves by deforming the rubber plate 5, but in response to large vibrations, small holes 6 are provided to make it difficult for fluid to pass through. and absorb it. Also, against small vibrations from the engine, the cylindrical rubber member 7 of the engine mount 2 body
The vibrations were absorbed by softening the rubber material, slightly changing the volume of the chamber 4, and moving the fluid up and down through the small holes 6.

However, in this conventional mechanism, the softness of the rubber member 7,
Not only is it extremely difficult to set the size of the small hole 6, but once it has been determined, it is almost impossible to change it again. Therefore, it was not possible to finely change the size of the small hole in response to the magnitude of vibration and control vibration absorption in response to each of the vibrations, so it was insufficient as a vibration absorption mechanism.

The present invention was proposed in order to eliminate the above-mentioned drawbacks of the conventional technology, and it is possible to arbitrarily change the spring constant by enclosing a magnetic fluid and controlling the flow of the fluid electrically, thereby improving vibration absorption. The present invention aims to provide a magnetorheological damper that can be precisely controlled.

The present invention will be explained below with reference to the embodiments shown in the drawings. Fig. 1 shows the first embodiment of the invention, and Fig. 2 shows the second embodiment of the invention.
This is an example. In FIG. 1, 8 is an electromagnet, and as shown in FIG. 3, the electromagnet 8 is orthogonal to the axis of the chamber 4, and a coil 10 is wound around a circular iron core 9 arranged to surround the axis. It is composed of
The coil 10 is taken out to the outside as a lead wire 11 and connected to a power source (not shown). Further, the electromagnet 8 is mounted inside a chamber made of a non-magnetic material 12.

A part of the iron core 9 is cut out to form an orifice 13, and the coil 10 is inserted into the orifice 13.
The orifice 13 is arranged to coincide with the small hole 6.
The small hole 6 communicates the chamber 4 with the chamber 14 below the rubber plate 5 through holes 15, 15 provided in the non-magnetic material 12. and chambers 4, 14, holes 15, 15,
The small holes 6 are filled with magnetic fluid. A magnetic fluid is made by mixing solid particles such as SF ₃ O ₄ in a fluid such as water or oil in an amount of about 4 to 18% by volume.

When a current is passed through the coil 10, magnetic flux is concentrated in the orifice 13 where the iron core 9 is cut. Therefore, while current is flowing through the electromagnet 8, the apparent viscosity of the magnetic fluid changes in the small hole 6, and this apparent viscosity changes with the magnitude of the current (magnetic field) as shown in Figure 5. Change over time. Therefore, the flow resistance of the small hole 6 changes. Note that both ends of the iron core 9 may be cut at right angles as shown in FIG.
It may be cut diagonally so that the central portion protrudes as shown in FIG. 7, or the protruding portions 16, 16 may be provided in the center as shown in FIG. If the center portions of both ends are made to protrude as shown in FIGS. 7 and 8, a strong magnetic flux can be formed in these portions. Further, reference numeral 17 in FIG. 1 is an iron ring that prevents the rubber member 7 from bulging outward.

Next, to explain the operation, when the rubber member 7 is deformed due to vibration when no current is passed through the electromagnet 8, the small holes located in the orifices 13 at both ends of the iron core 9
Through this, the magnetic fluid in the chambers 4 and 14 deforms the rubber plate 5 and moves. However, in this case, small hole 6
Since the magnitude of is constant, vibration absorption cannot be precisely controlled.

Next, when the electromagnet 8 is energized, the orifice 13,
That is, the magnetic flux is concentrated in the small hole 6 portion, and the apparent viscosity value of the magnetic fluid in the small hole 6 portion changes with the magnitude of the current. Therefore, the flow resistance of the small hole 6 can be changed arbitrarily, and vibration absorption can be controlled more precisely.

FIG. 2 shows a second embodiment, and the difference from FIG.
8, only water or oil is placed in the chamber 4, and magnetic fluid is filled only in the chamber 14 that includes the small holes 6, but there is no difference in operation and effect. That is, the deformation of the rubber member 7 is transmitted to the magnetic fluid in the chamber 14 via the water or oil in the chamber 4 and the rubber plate 18, and the magnetic fluid moves through the small holes 6.

Next, a method of controlling the magnitude of the current flowing through the electromagnet 8 will be explained with reference to the system diagram in FIG. 4. Vibrations come from the engine 19, vibrations come from the displacement of the suspension 20 from the road surface,
Possible causes include the magnitude of the pressing force on the brake 21.

The vibration coming from the engine 19 changes depending on the number of rotations, and this can be determined by the tachometer 22. Also, the speed can be determined by the increase in rotational speed from the speedometer 23 and by the magnitude of the brake pedal force. The acceleration/deceleration due to this speed and brake pedal force is determined by the engine 19 and the G sensor 2.
Measurement can be performed by attaching 4.

Therefore, the engine 19 and the suspension 2
0, vibration data from the brake 21, tachometer 22, speedometer 23, etc. is stored in the microcomputer 25, and according to the input from each part,
A command is sent from the microcomputer 25 to the variable resistor 26, and the variable resistor 26 operates, sending a current of a magnitude corresponding to each input to the electromagnet 8, and depending on this current value, the magnetic fluid in the small hole 6 is increased. The apparent viscosity value is controlled to absorb vibrations more precisely.

Figure 5 shows the relative viscosity value and the strength of viscosity and magnetization M _H
A diagram showing the relationship between is shown. The relative viscosity value represents the viscosity of the magnetic fluid, and the viscosity η at a certain magnetization strength
It is expressed as the ratio η/η _O of the viscosity η _O at the magnetization strength OO _e .

Figure 6 is a diagram showing the relative displacement of the mount, 2
7 indicates vibrations coming from the engine, and large waves 28 indicate vibrations coming from the road surface.

As explained in detail above, the present invention is configured, and the magnetic flux generated in the orifices at both ends of the iron core of the electromagnet is aligned with the orifices according to the magnitude of the current according to the state of each vibration change. The apparent viscosity of the magnetic fluid in the pores changes. Therefore, the flow resistance of the small hole is controlled, a spring constant adapted to each vibration can be obtained, and vibration absorption can be controlled more precisely.

Further, the present invention provides a circular electromagnetic iron core that is perpendicular to the axis of each chamber and surrounds the axis, and that a part of the iron core is cut out to form an orifice, and a portion other than the orifice is disposed. Since the coil is wound around the iron core and the orifice is aligned with the small hole, the space in the height direction of the damper can be reduced, and the number of turns of the coil can be increased with a shorter length. You can take it. Furthermore, with the above configuration, all of the magnetic flux generated by the coil can be transmitted to the orifice, making it possible to further improve efficiency.

[Brief explanation of drawings]

1 and 2 are vertical cross-sectional views of a damper showing an embodiment of the present invention, and FIG. 3 is an A of FIG. 1 and FIG. 2.
~ A sectional view, FIG. 4 is a system diagram in which a microcomputer is connected to a vibration generation source that generates vibrations that are absorbed by a damper, showing an embodiment of the present invention;
Figure 5 is a diagram showing the relative viscosity of the magnetic fluid and the relationship between viscosity and magnetization strength M _H. Figure 6 is a diagram showing the relative displacement of the mount. It is a top view showing an iron core different from the figure. Explanation of the main parts of the diagram, 2... Engine mount (damper), 4, 14... Chamber, 5... Rubber plate, 6
...Small hole, 7...Rubber member, 8...Electromagnet, 9...
...Iron core, 10...Coil, 13...Orifice,
19... Engine (vibration body), 20... Suspension (vibration source), 21... Brake (vibration source),
25... Microcomputer (mechanism into which data is input), 26... Variable resistor (mechanism that sends a current of a magnitude depending on its state).

Claims (1)

[Claims] 1. A chamber interposed between a frame and a vibrating body disposed on the frame, the peripheral wall of which is formed of a cylindrical rubber member, and the chamber whose upper surface is formed of a rubber plate are connected through small holes. In the damper, each chamber is filled with a liquid so that when the rubber member is deformed due to vibration, the liquid moves through the small hole to absorb the vibration. A circular electromagnet's iron core is arranged perpendicularly to the core and surrounds the axis, a part of the iron core is cut out to form an orifice, a coil is wound around the iron core in a part other than the orifice, and a coil is wound around the iron core in a part other than the orifice. are made to coincide with the small holes, and a magnetic fluid is used as the liquid moving through the small holes, and a microcomputer is separately provided into which vibration data from the vibrating body and other vibration sources is input, and each of the above A magnetic fluid type damper, characterized in that it is provided with a mechanism configured to send a current of a magnitude corresponding to the state to the electromagnet when a state of vibration change is input.