JPH035693Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to shock absorbers used in vehicles, etc., and in particular,
It consists of a stepless damping force adjustment method using electrorheological fluid.

<Prior art> Switching the damping force in a conventional shock absorber of this type is as follows:
By switching and matching the opening of the passage between the upper and lower cylinder chambers provided in the piston and several types of orifices with different diameters provided in the rotary valve at the tip of the piston rod, a predetermined resistance is achieved for the oil flowing through the passage. Many configurations have been adopted in which the piston movement is restricted by having a

By the way, in the orifice switching by such mechanical operation, the opening is closed or kept in an appropriate open state during the time period during which the orifice is moved between the arrangement positions, that is, during the switching operation. As a result, the damping force could not be changed smoothly, resulting in an uncomfortable ride for the equipped vehicle.

Therefore, it is strongly desired that the damping force in this type of shock absorber be able to be changed steplessly and smoothly.

In order to meet this demand, in order to adjust the damping force by adjusting the viscosity of the liquid passing through the orifice that communicates between the upper and lower chambers of the cylinder, we developed a method using an electrorheological fluid as the working fluid (for example,
60-142334) has been proposed.

According to this means, an electrode arrangement means is provided to form an electric field acting on the passage, and by adjusting the electric field strength, the viscosity of the fluid in the passage can be changed, and the viscosity of the fluid in the passage can be changed. By adjusting the electric field strength, stepless adjustment of the damping force is possible.

<Problems to be Solved by the Invention> According to the means using this electrorheological fluid, as described above, since an electrode for applying a voltage is required as an electric field forming means, the assembly structure poses a problem. That is, when attempting to assemble it into a shock absorber, mechanical components of the interelectrode passage (for example, a harness in the case of multilayer slit formation) that can deal with problems of insulation treatment between electrodes and high-pressure high-speed liquid flow inside the shock absorber. It is difficult to maintain strength and construct an electrically insulating structure, and as a result, the degree of freedom in designing this component is limited, making it difficult to obtain the desired effect.

Therefore, this type of conventional means still leaves much room for improvement in its configuration.

Therefore, the present invention uses an electrorheological fluid and varies the viscosity of the fluid, thereby making it possible to perform stepless adjustment of the damping force in the shock absorber. The purpose of this invention is to not only improve control efficiency and adjustment accuracy by improving the formation of the liquid feeding path and the configuration of the electric field generating means that acts on it, but also to simplify the device configuration. It is.

<Means for Solving the Problems> According to the present invention, in a hydraulic shock absorber using an electroviscous liquid whose viscosity changes due to an electric field, the upper and lower chambers of the cylinder are divided by a piston. A passage connecting the two is formed by an annular gap between the outside of the cylinder and an outer cylinder surrounding the cylinder, and a part of the outer cylinder forming the annular gap is electrically insulated from other parts. This can be achieved by configuring it as an independent part and using the independent part as one electrode for generating an electric field in a cross direction with respect to the passage.

<Operation> According to the above means of the present invention, the passage connecting the upper and lower chambers of the cylinder is formed on the outside of the cylinder. The outer cylinder forming the annular gap serving as the passage acts as an external electrode that applies a cross electric field to the passage by electrically grounding the cylinder body.

Therefore, as the piston rod expands and contracts, and the piston that is integral with it moves within the cylinder,
The electrorheological fluid filled in the cylinder flows between the upper and lower chambers through the flow rate control section of the normally configured cylinder equipment, and also flows through the passageway between the upper and lower chambers as a side path of this flow rate control section. flows.

At this time, when a high voltage is applied to the electrodes to generate a cross electric field in the passage, the viscosity of the electrorheological fluid flowing through the passage changes depending on the electric field strength at that time, so the flow as it passes through the passage changes. road resistance changes,
It is possible to change the pressure in the upper and lower chambers of the piston. As a result, the damping force of the anti-vibration operation by this piston can be adjusted.

By changing the voltage applied between the electrodes, this damping force can be variably adjusted to an arbitrary value in accordance with this change.

Next, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

<Example> In a vertical cross-sectional side view of a main part showing an example of the present invention, a passage 3 is formed by an annular gap between a cylinder 1 of a double-cylinder type and its outer cylinder 2. . Reference numeral 4 denotes a piston, and the cylinder upper chamber 1a and the cylinder lower chamber 1a divided by this piston have passage ports 3a each opening toward the passage 3.
and 3b are drilled.

In the outer cylinder 2, the part 2a forming the annular gap is formed of a cylindrical body made of a conductive material that is separate from the other part 2b which is attached integrally with the cylinder body. Flanges 5a and 5b are provided at the ends of the tubes that join these two parts 2a and 2b, respectively, and both flanges 5a and 5 are provided with an insulating material 6 made of rubber or the like that also functions as a packing.
b with bolts 7, and these two parts 2
a and 2b are attached integrally.

The piston 4 is provided with a flow rate control section 8 and a check valve 9 having a conventionally well-known configuration, while a check valve 10 and a flow rate control section 11 provided at the bottom of the cylinder lower chamber 1a are provided. An external pressurized tank 12 is connected thereto. The pressurized tank 12 is configured to transmit the pressure of the high-pressure gas chamber 13 to the storage chamber 15 via a free piston 14.

The cylinder portion and pressurized tank portion are filled with an electrorheological fluid 16.

Additionally, 17 indicates a piston rod.

According to the embodiment having such a configuration, when the piston rod 17 on the vehicle body connection side first moves in the direction of extension as the vehicle body vibrates, when the piston rod 17 is installed in a vehicle, the piston integrated therewith moves. 4
moves to the upper left in FIG.

This movement causes the electrorheological fluid 16 in the cylinder upper chamber 1a to flow to the flow rate control section 8 provided in the piston 4.
It flows through the piston lower chamber 1b, and also flows through a flow path system that passes from the passage port 3a to the passage 3 and from the other passage port 3b to the cylinder lower chamber 1b.

On the other hand, a voltage corresponding to the current state of vibration detected by a vibration detection mechanism (not shown) is applied to the part 2a of the outer cylinder 2 between the cylinder 1 and the passage 3 between the parts 2a and 2a. A cross electric field is applied depending on the voltage. Therefore, the viscosity of the electrorheological fluid 16 passing through this electric field changes depending on the electric field strength at that time, thereby changing the flow path resistance when passing through the passage 3. As a result, the damping force is automatically adjusted to change the pressure in the cylinder upper chamber 1a according to the state of vibration. Moreover, since the adjustment of this damping force corresponds to the voltage applied between the previous portion 2a and the cylinder 1, it is easily possible to control this damping force steplessly. In particular, when the passage 3 is formed by an annular gap as in this embodiment, the surface area of the passage can be increased and the flow can be made laminar. Since pressure loss is proportional to viscosity, this structure is easy to design and control.

Also, when the piston rod 17 moves toward the pressure side, by setting the operating point of the check valve 9 of the piston 4 to a certain level, the lower piston chamber 1 is moved when the piston 4 moves toward the right in FIG.
Since a part of the electrorheological fluid 16 of b can flow back into the passage 3, the damping force can be adjusted in the same manner as described above.

<Effects of the invention> As described above, according to the shock absorber of the present invention, the electric field strength of the fluid passing through the electric field is changed by using an electrorheological fluid whose viscosity changes according to the cross electric field strength, and the damping effect is reduced. In order to enable stepless adjustment of the force, this fluid passage is formed outside the cylinder, and the electrodes can also be placed outside, so the area and length of the passage consisting of the annular gap can be increased. Since it is possible to obtain a large flow path resistance with a relatively low viscosity during this period, it is possible to adjust the damping force over a wide control range even with relatively low voltage control. In addition to exhibiting excellent functional effects, the passage between the upper and lower chambers of the cylinder and the main mechanical parts such as the electrodes are located outside the cylinder, making it easy to process and assemble, while maintaining electrical insulation and mechanical strength. The shock absorber of the present invention has a simple structure and excellent effects as a mechanism of this type, and is extremely useful in practice.

In addition to the configuration of the illustrated embodiment, the shock absorber of the present invention has the following features:
Of course, the present invention can also be applied to a single cylinder gas type hydraulic shock absorber.

[Brief explanation of the drawing]

The drawing is a longitudinal sectional side view of the main parts of an embodiment of the shock absorber of the present invention. DESCRIPTION OF SYMBOLS 1... Cylinder, 1a... Cylinder upper chamber, 1b... Cylinder lower chamber, 2... Outer cylinder, 3... Passage, 3a, 3b...
Passage port, 4...piston, 5a, 5b...flange,
6... Insulating material, 16... Electrorheological fluid.

Claims (1)

[Scope of utility model registration request] In a hydraulic shock absorber using an electrorheological liquid whose viscosity changes due to an electric field, a passage connecting the upper and lower chambers of the cylinder, which are separated by a piston, is connected between the outside of the cylinder and the outer cylinder surrounding it. an annular gap, and a part of the outer cylinder forming the annular gap is configured as an independent part electrically insulated from other parts, and the independent part generates an electric field in a cross direction with respect to the passage. A variable damping force type hydraulic shock absorber, characterized in that one electrode is used for damping.