JPH0333936B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vehicle height adjustment device using magnetic fluid.

In conventional vehicle height adjustment devices, for example, oil and compressed gas are sealed inside a cylinder mechanism, and the length of the cylinder mechanism can be adjusted by changing the amount of oil or compressed gas sealed from the outside. . Therefore, this type of vehicle height adjustment device not only allows the vehicle height to be adjusted, but also supports the vehicle body elastically using the repulsive force of the compressed gas, so there is no need to provide a separate shock absorbing coil spring. There are advantages.
Furthermore, by providing an orifice in the piston portion of the cylinder mechanism, oil flow resistance can be created and damping force can be exerted.

However, with conventional devices of this type, the damping force is uniquely determined by the opening amount of the orifice, the viscous resistance of the oil, etc., so it is not possible to obtain the desired damping force depending on the road surface condition and other conditions. There is a drawback. Furthermore, the conventional vehicle height adjustment device has a problem in that the damping force cannot be arbitrarily adjusted depending on the degree of amplitude.

The present invention has been made based on the above circumstances, and an object of the present invention is to provide a vehicle height adjustment device that can arbitrarily adjust damping force.

That is, the present invention is provided between a vehicle body and an axle-side member, and a magnetic fluid and compressed gas are sealed inside, and the length can be adjusted by changing the amount of at least either the magnetic fluid or the compressed gas. A vehicle height adjusting device characterized by comprising: a cylinder mechanism having a cylindrical structure, an orifice provided in a piston portion of the cylinder mechanism, and an electromagnetic coil provided in a cylinder body located near the outside of the piston portion. be.

In the present invention having the above configuration, by controlling the current flowing through the electromagnetic coil, the apparent specific gravity of the magnetic fluid passing through the orifice can be changed, and the damping characteristics can be changed accordingly. Further, it is possible to exert different damping forces depending on the relative position of the piston portion with respect to the electromagnetic coil, and it is possible to obtain effective damping force changes depending on the degree of amplitude and the like.

A first embodiment of the present invention will be described below with reference to FIG. In the figure, reference numeral 1 denotes a cylinder mechanism provided between the vehicle body and the axle side member, and this cylinder mechanism 1 is inserted into a cylinder body 2 and is movable in the axial direction into this cylinder body 2. a rod portion 3, and a cover 4 provided to surround the rod portion 3 and the outside of the cylinder body portion 2.
It is composed of the following.

More specifically, a mounting part 5 is provided at the lower part of the cylinder body 2 for mounting to an axle side member (not shown), and a seal is provided at the upper part of the cylinder body 2 at a portion that makes sliding contact with the rod part 3. 6 is provided. Further, a magnetic fluid storage chamber 7 is provided in the cylinder body 2, and this chamber 7 is filled with magnetic fluid.

On the other hand, the rod part 3 includes a cylindrical rod main body 10, a free piston 11 provided inside the rod main body 10, and a piston part 12 attached to the lower end of the rod main body 10. The rod body 10 includes an end member 13 provided at the upper end of the rod body 10. Threaded portion 1 of this end member 13
4 is fixed to a member 16 on the vehicle body side using a nut 15.

Further, a high-pressure gas chamber 20 for sealing nitrogen gas or the like is formed on the upper side in the figure with the free piston 11 as a boundary, and a magnetic fluid storage chamber 21 is formed on the lower side in the figure. Further, the piston portion 12 is provided with an orifice 22 for communicating the upper and lower magnetic fluid chambers 7 and 21. This orifice 22... is an elastically deformable plate valve 2.
3 and 24, the opening amount may be changed according to the fluid pressure.

The cylinder body 2 is provided with a pair of electromagnetic coils 25 and 26 located above and below the piston portion 12. Both electromagnetic coils 25 and 26 are connected to each other at a neutral position 0 that divides the distance between them into two.
They are arranged in a polar relationship such that the magnetic fields of 26 cancel each other out.

Further, an auxiliary chamber 32 is connected to the high-pressure gas chamber 20 via a pipe 30 and an on-off valve 31.
This auxiliary chamber 32 is internally partitioned by a free piston 33, and has a gas chamber 34 on its upper side and an oil chamber 35 on its lower side. A hydraulic pressure generation source 37 is connected to this oil chamber 35 via a switching valve 36. 38 is a drain.

In this embodiment configured as described above, the relative height of the rod portion 3 with respect to the cylinder body portion 2 is detected by a detector using a limit switch or the like (not shown), and the piston portion 12 is always kept at a constant neutral position 0. It is adjusted so that the That is, when the rod portion 3 is pushed down from the standard position, such as when the load on the vehicle body is large, the switching valve 36
is activated, oil from the hydraulic pressure generation source 37 is sent into the auxiliary chamber 32, and the free piston 33 is pushed up, so that the gas in the auxiliary chamber 32 is sent into the high pressure gas chamber 20 in the cylinder mechanism 1, and the free piston 33 is pushed up. Press down on 11. This causes the rod portion 3 to extend to the reference position, and the piston portion 12 to return to the predetermined neutral position 0. On the other hand, when the rod portion 3 is extended beyond the standard position due to a light load, etc., the switching valve 36 operates in the opposite manner to the above, and by removing oil from the auxiliary chamber 32, the amount of gas filled in the high-pressure gas chamber 20 is reduced. and the rod portion 3 is at the predetermined neutral position 0.
descend to Therefore, the vehicle height can always be kept constant.

Also, when the rod portion 3 expands and contracts due to unevenness of the road surface, the piston portion 12 moves up and down, causing magnetic fluid to flow through the orifice 22, damping it based on viscous resistance, ejection resistance, etc. Force arises.

According to the above configuration, there is no need to increase the pressure of the magnetic fluid with a pump, and the use of the expensive magnetic fluid can be limited to the inside of the cylinder, and a small amount is required, resulting in a reduction in price. Furthermore, since high pressure is constantly applied to the magnetic fluid, there is no air ration at the orifice, and a stable damping force can be obtained.

This damping force can be changed as follows. That is, the upper and lower electromagnetic coils 2
When the magnetic coils 5 and 26 are energized and excited, the apparent specific gravity of the magnetic fluid changes in the area covered by the magnetic field of each electromagnetic coil 25 and 26. However, since the magnetic forces are canceled out near the neutral position 0, when the piston portion 12 moves with a small amplitude near the neutral position 0, the damping force hardly increases due to a change in the specific gravity of the magnetic fluid.
However, as the amplitude increases and the piston portion 12 approaches the electromagnetic coils 25 and 26, the specific gravity of the magnetic fluid changes in this region due to the action of the magnetic field, so the resistance of the magnetic fluid passing through the orifice 22 increases. A large damping force can be obtained. Moreover, by changing the current value applied to the electromagnetic coils 25 and 26 and changing the strength of the magnetic field, the damping force can be adjusted as desired. Furthermore, in the case of small-amplitude vibrations that occur near the neutral position 0, the resistance that the piston portion 12 receives becomes small for the above-mentioned reasons, and is effective in absorbing minute vibrations.

Furthermore, according to the embodiment described above, communication and isolation between the two gas chambers 20 and 34 can be established by opening and closing the on-off valve 31, so the magnitude of the spring constant can be changed by increasing or decreasing the volume of the gas chamber. It has the advantage of being adjustable in two stages. Furthermore, by adding an auxiliary chamber and an on-off valve, it is also possible to adjust the spring constant in multiple stages.

Note that in the above description, the height is automatically adjusted so that the piston portion 12 is always at a constant neutral position 0, but the height is not limited to this, and for example, the piston portion 12 may be adjusted manually. The standard height of the vehicle, that is, the height of the vehicle, may be arbitrarily adjusted. However, in this case, both electromagnetic coils 25 and 26 are configured to be movable in the vertical direction relative to the cylinder body 2, and the neutral position 0 of each electromagnetic coil 25 and 26 is adjusted to the reference height of the piston portion 12. Make it.

Note that FIG. 2 shows a second embodiment of the present invention, and since the basic structure is the same as that of the first embodiment, common parts are given the same reference numerals and explanations are omitted.
The differences will be explained below.

That is, in this second embodiment, the piston part 1
2 is provided with a permanent magnet 28, and an intermediate electromagnetic coil 27 is provided at a neutral position 0 between the upper and lower electromagnetic coils 25 and 26. The intermediate electromagnetic coil 27 is arranged in such a polar relationship that it cancels out the magnetic force of the permanent magnet 28 when the piston portion 12 is in the neutral position 0. Further, the upper and lower electromagnetic coils 25 and 26 are arranged with polarities that attract the permanent magnet 28, for example.

Therefore, according to this second embodiment, when the piston portion 12 is shifted vertically from the neutral position 0, a large magnetic field is generated around the piston portion 12,
A greater damping effect can be achieved compared to the first embodiment.

Also in the second embodiment, as in the first embodiment, the damping force can be changed according to the magnitude of the current applied to the electromagnetic coils 25, 26, 27, and the damping force can be changed according to the degree of amplitude. This has the effect that it can be obtained.

Further, as described in the first embodiment, the reference height of the piston portion 12 may be changed by manual operation. In this case, the neutral point of each electromagnetic coil 25, 26, 27 is 0. Each electromagnetic coil is configured to slide up and down so that it is located at the reference height of the piston portion 12.

Furthermore, in each of the above embodiments, the length of the cylinder mechanism 1 is adjusted by changing the amount of compressed gas sealed, but the length can be adjusted by changing the amount of magnetic fluid in the cylinder mechanism 1, for example. You may do so.

Furthermore, it is of course possible to carry out the present invention by variously modifying the shapes and structures of the cylinder mechanism, piston portion, orifice, electromagnetic coil, etc. without departing from the gist of the present invention. be.

As described above, according to the present invention, the damping force can be changed by controlling the magnetic field applied to the magnetic fluid, and the damping force can be changed depending on the relative position of the piston portion with respect to the electromagnetic coil provided in the cylinder body. Therefore, it is possible to provide a vehicle height adjustment device that has excellent damping force, such as being able to exhibit a damping force that varies depending on the amplitude.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of a vehicle height adjusting device showing a first embodiment of the invention, and FIG. 2 is a longitudinal sectional view showing a second embodiment of the invention. 1... Cylinder mechanism, 7... Magnetic fluid storage chamber,
12...Piston part, 20...High pressure gas chamber, 2
1... Magnetic fluid storage chamber, 22... Orifice, 2
5, 26, 27... Electromagnetic coil.

Claims (1)

[Scope of Claims] 1. A magnetic fluid and a compressed gas are sealed between the vehicle body and the axle side member, and the length can be adjusted by changing the amount of the magnetic fluid or compressed gas. A vehicle height adjustment device comprising: a cylinder mechanism; an orifice provided in a piston portion of the cylinder mechanism; and an electromagnetic coil provided in a cylinder body located near the outside of the piston portion. 2. The vehicle height adjustment device according to claim 1, wherein the electromagnetic coil is movable in the axial direction of the cylinder body.