JPH06101737A - Buffer device - Google Patents

Abstract

PURPOSE:To prevent the electric shock and leakage, secure advantageousness in management and maintenance, and expect an improvement in versatileness. CONSTITUTION:A rod side chamber A and a piston side chamber B are dividedly formed in a cylinder by installing a piston part 3 in a slidable manner in the cylinder 1, and the piston side chamber is allowed to communicate to the rod side chamber through an extension side check valve 3a in the piston part, and a control gap S which communicates to the rod side chamber A and a reservoir chamber R2 is formed between the cylinder 1 and an inner tube 11. The reservoir chamber communicates to the piston side chamber through a pressure side check valve 14c in a base valve part 14 arranged at the lower edge part of the cylinder, and both the edge parts of the cylinder and the inner tube are joined with a bearing the valve body of a base valve through an insulating member 8, and the cylinder is used as one electrode member, and the inner tube is used as the other electrode member.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock absorber capable of adjusting a generated damping force by utilizing the property that an electrorheological fluid changes its viscosity according to an applied voltage.

[0002]

2. Description of the Related Art In recent years, for example, a hydraulic shock absorber used as a shock absorber for an automobile is constructed so that the generated damping force is adjusted according to the condition of the road surface of the automobile. Is desired. For that reason, in the hydraulic shock absorbers that have been conventionally proposed, in general, when the piston part slides in the cylinder due to the piston rod protruding and retracting with respect to the cylinder, damping force is generated. A predetermined damping force is generated by the passage of the hydraulic oil through the section, and the mechanism of the damping force generation in the damping force generation unit is mechanically changed, or the hydraulic oil passing through the damping force generation unit is changed. The flow rate is increased / decreased to adjust the generated damping force.

As a result, when the damping force generating section is formed of a damping characteristic such as a throttle or a valve, the damping force generated within the characteristic damping range is adjusted. Therefore, when the hydraulic shock absorber equipped with this damping force generating unit is mounted on an automobile, the initial purpose of adjusting the generated damping force according to the condition of the road surface on which the automobile is traveling. There is a danger that the

If the damping force generating portion is constructed to have a structure having various throttles, valves, etc. so as to be able to exert a damping force having various characteristics, the structure of the hydraulic shock absorber becomes complicated and its productivity is increased. Not only will the inconvenience be lowered and maintenance will be troublesome, but also the control will be complicated in response to the complicated structure, and expensive parts will be used a lot. As a result, inconveniences such as an increase in production cost are likely to occur.

In view of this, in recent years, an electrorheological fluid having a property that its viscosity changes according to an applied voltage has been discovered, and for example, it is shown in FIG. 2 disclosed in Japanese Utility Model Publication No. 3-5698. A shock absorber using an electrorheological fluid having such a structure has been proposed.

That is, the shock absorber is formed in the form of a conventional hydraulic shock absorber, and the tip of the piston rod 2 which is inserted into and retracted from the cylinder 1 slides inside the cylinder 1. It has a piston portion 3 which moves and which partitions and forms a rod side chamber A and a piston side chamber B in the cylinder 1.

The rod-side chamber A and the piston-side chamber B are filled with an electrorheological fluid, and the rod-side chamber A and the piston-side chamber B are arranged in parallel with the extension-side check valve 3a provided in the piston portion 3. It is supposed that they are communicated with each other via the diaphragm 3b.

The cylinder 1 has a port 1a at the upper end and a port 1b at the lower end, and the side chambers A and B are communicated with the outside via the ports 1a and 1b, respectively. .

A reservoir tank T is provided outside the cylinder 1, and a tank chamber T1 forming the reservoir tank T is provided with a reservoir chamber T2 and a gas chamber T therein.
3 and a compartment forming free piston T4 are slidably accommodated therein. The chamber T2 is communicated with the piston side chamber B in the cylinder 1 via the pipe P.

On the other hand, a so-called outer cylinder is provided on the outer peripheral side of the cylinder 1 so as to form a chamber R. The outer cylinder is composed of the head side cylindrical body 4 and the bottom side cylindrical body. 5 and an intermediate tubular body 6. The chamber R is supposed to communicate with the side chambers A and B via the ports 1a and 1b for opening and closing the cylinder 1.

A bearing member 7 is screwed onto the inner periphery of the upper end of the head-side tubular body 4, and a piston rod 2 is slidably inserted in the central portion of the bearing member 7. The head-side tubular body 4 has a flange portion 4a at its lower end, and is connected to the upper end of the intermediate tubular body 6 through the flange portion 4a.

The bottom side tubular body 5 is provided with a pressure side check valve 5a and a throttle 5b in parallel with the pressure side check valve 5a at the lower end thick portion thereof, and the pressure side check valve 5a and the throttle 5b are provided in the reservoir tank T. The chamber T2 is communicated with the piston side chamber B. The bottom side tubular body 5 has a flange portion 5c at its upper end, and is connected to the lower end of the intermediate tubular body 6 via the flange portion 5c.

The intermediate tubular body 6 has flange portions 6a and 6b at the upper and lower ends thereof, respectively.
a and 6b are connected to the flange portion 4a of the head-side tubular body 4 and the flange portion 5c of the bottom-side tubular body 5, which are opposed to each other, by bolts and nuts 9 via an insulating material 8.

The intermediate tubular body 6 has an interval of about 1 mm between the inner circumference thereof and the outer circumference of the cylinder 1 so that a part of the chamber R is narrowed. The control gap S is supposed to be formed. The control gap S functions to change the viscosity of the electrorheological fluid interposed in the electric field to a hardening tendency according to the amount of applied voltage when the electric field is generated here.

Further, in this conventional example, the cylinder 1 is used as one electrode member, while the intermediate tubular body 6 is used as the other electrode member. The extended electric wire E1 has one electrode member, that is,
The electric wire E2 connected to the upper end side tubular body 4 electrically connected to the cylinder 1 and extended from the controller C is connected to the intermediate tubular body 6 serving as the other electrode member.

Therefore, according to this conventional proposal of the shock absorber using the electrorheological fluid, when the piston portion 3 slides in the cylinder 1 by retracting the piston rod 2 with respect to the cylinder 1, The electrorheological fluid will pass through the control gap S arranged outside the cylinder 1. At this time, a predetermined voltage is applied to both electrode members to develop an electric field in the control gap S. By doing so, the viscosity of the electrorheological fluid is changed to a hardening tendency according to the applied voltage amount in the electric field.

Therefore, on condition that the applied voltage is maintained, the flowability of the electrorheological fluid in the control gap S tends to be impeded thereafter, and as a result, the piston portion 3
Slidability in the cylinder 1 is hindered, that is, a damping action is exhibited, and by appropriately selecting the applied voltage amount to both electrode members, the degree of the damping action to be produced is arbitrary. Can be adjusted to.

If the shock absorber as the above-mentioned conventional proposal is mounted on an automobile, it becomes possible to adjust the degree of damping action according to the condition of the road surface on which the automobile travels. It can be improved to a preferable state.

[0019]

However, in the shock absorber using the electrorheological fluid as the conventional example described above,
There is a security drawback and there is a danger that the desired damping effect cannot be expected. That is, in the shock absorber according to the conventional example, the upper end side tubular body 4 and the lower end side tubular body 5 electrically connected to both electrode members, that is, the cylinder 1 which is one electrode member.
At the same time, the intermediate tubular body 6 serving as the other electrode member is exposed to the outer circumference of the shock absorber.

Therefore, both of the electrode members are in a so-called exposed state, and there is a risk of electric shock if the human body touches them. Further, even when mounted in a vehicle, there is a risk of current leakage due to contact of current with other parts through the bearing member 7 etc., resulting in power loss. In the case of the above-mentioned conventional example, the flange portions 4a, 6a and 5c, 6 are provided outside the shock absorber.
Since b is formed in a protruding form, there is a disadvantage that the chances of the electric shock and the electric leakage increase.

Further, in view of the fact that the control gap S is required to be maintained at about 1 mm, in the above-mentioned conventional example, the intermediate tubular body 6 becomes uneven. Although it is absolutely necessary to avoid such a situation as described above, there is a risk that a dent may be formed due to a stone colliding with the outer periphery of the intermediate tubular body 6 while the shock absorber is mounted on an automobile, for example. If the depression is formed, the control gap S
There is a danger that the interval of will be out of order, and the expected damping effect cannot be expected.

The maintenance of the space in the control gap S is required even when the shock absorber is transported as a product, and there is a disadvantage that its management becomes troublesome.

The present invention was devised in view of the above-mentioned circumstances, and the purpose thereof is that there is no risk of electric shock or leakage, it is advantageous in management and security, and it has a predetermined attenuation. It is an object of the present invention to provide a shock absorber using an electrorheological fluid, which can realize the action as set and which can be expected to improve its versatility.

[0024]

In order to achieve the above-mentioned object, an inner tube is arranged outside the cylinder of a shock absorber using electrorheological fluid according to the present invention, and an outer tube is arranged outside the inner tube. And a reservoir chamber is formed between the inner tube and the outer tube, and the piston portion is slidably accommodated in the cylinder to partition and form the rod side chamber and the piston side chamber in the cylinder. The piston side chamber is made to communicate with the rod side chamber via the expansion side check valve in the piston section, and a control gap is formed between the cylinder and the inner tube so as to communicate with the rod side chamber and the reservoir chamber. Is communicated with the piston side chamber via a pressure side check valve in a base valve section arranged at the lower end of the cylinder, and is connected to the cylinder. -Both ends of the tube are connected to the bearing and the valve body of the base valve through an insulating material, and the cylinder is used as one electrode member while the inner tube is used as the other electrode member. It is what

[0025]

The outer tube serves as a so-called cover body and can prevent in advance the external force such as impact from acting on the outer circumference of the inner tube which is the other electrode member forming the so-called control gap inside the shock absorber. Therefore, it becomes possible to maintain the spacing of the control gap as set. Further, the cylinder and the inner tube, which are the electrode members, are arranged in the outer tube, and since each electrode member is insulated by the insulating material, the electrode member is not exposed to the outside,
Since electric current does not flow to the outside through other members, electric shock and leakage are prevented.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the illustrated embodiment. The embodiment shown in FIG. 1 is a shock absorber for an automobile, which comprises a cylinder 1 and an inner member. It has a tube 10 and an outer tube 11, and is formed into a so-called triple cylinder type as opposed to a so-called double cylinder type.

The cylinder 1 is formed in a so-called single tube structure, the piston rod 2 is inserted into and retracted from the inside of the cylinder 1, and the rod side chamber defined by the piston portion 3 slidably accommodated in the inside thereof. A and a piston side chamber B are provided. Then, the rod side chamber A and the piston side chamber B
Is filled with an electrorheological fluid whose viscosity changes when a voltage is applied.

The cylinder 1 has a bearing member 12 whose upper end has a piston rod 2 inserted through the center thereof.
Is blocked while being connected to the
The bearing member 12 also closes the upper end of the inner tube 10 under the insulating material 8. The bearing member 12 is connected to the inner periphery of the lower end side of the cap member 13 that holds the seal member 16 and inserts the piston rod 2. The cap member 13 has the outer periphery on the lower end side connected to the inner periphery on the upper end of the outer tube 11.

The lower end of the cylinder 1 is closed by the base valve portion 14, that is, the cylinder 1 is closed while being connected to the outer circumference of the valve body 14a forming the base valve portion 14 via the insulating material 8a. ing. Then, the valve body 14a is connected to the inner tube 10
It is supposed that the lower end of is also closed under the distribution of the insulating material 8.
The valve body 14a is supported in a state of being connected to a bottom member 15 disposed below the valve body 14a. The bottom member 15 has a lower end inner circumference of the outer tube 11 continuously connected to an upper end side outer circumference thereof. I am letting you.

The base valve portion 14 has a chamber R inside thereof.
1 and has the chamber R1 as a valve body 14
While communicating with the piston side chamber B through the port 14b opened in a and the pressure side check valve 14c arranged so as to close the upper end side of the port 14b, the chamber R1 is connected to the lower end of the valve body 14a. The reservoir chamber R2 formed between the outer tube 11, that is, the inner tube 10 is communicated with the outside through the formed communication hole 14d.

The piston portion 3 has a piston body 3c.
The piston-side chamber B is communicated with the rod-side chamber A via the port 3d that is opened and the extension-side check valve 3a that is arranged so as to close the upper end side of the port 3d.

On the other hand, the port 1a is provided at the upper end of the cylinder 1.
Is opened, and the rod side chamber A is inserted through the port 1a.
Is outside the cylinder 1, that is, the cylinder 1 and the cylinder 1.
It is supposed to communicate with a control gap S formed between the inner tube 10 and the inner tube 10. The spacing of the control gap S is about 1 m, as in the case of the conventional example described above.
The thickness is about m, and in this embodiment, it is set by adjusting the so-called thickness of the insulating material 8 described above.

A port 10a is opened at the lower end of the inner tube 10 so that the control gap S and the reservoir chamber R2 communicate with each other through the port 10a. As a result, the electrorheological fluid flowing through the control gap S always tends to flow into the reservoir chamber R2.

By the way, in order to develop an electric field in the control gap S, a predetermined voltage is applied to both the positive electrode member and the negative electrode member, but in this embodiment, one electrode member is used. The cylinder 1 is set to the plus side, and the inner tube 10 serving as the other electrode member is set to the minus side. The electric wire E1 extended from the external controller C is connected to the cylinder 1, and the inner tube 1
It is assumed that the electric wire E2 extended from the controller C is connected to 0.

The wires E1 and E2 are the outer tube 1
In the case of penetrating 1 through 1, the insulating material 1 is inserted in the outer tube 11 through the insertion hole 11a opened in a liquid-tight state.
1b is said to penetrate in a liquid-tight state. Electric wire E1
Is insulated and penetrates the inner tube 1 and is connected to the cylinder 1. The connection method is not limited to this. In this embodiment, the controller C
Is input with a signal from a vehicle height sensor C1 mounted on a vehicle, and when the shock absorber is mounted on the vehicle and travels on a road surface, both electrode members are applied to both electrode members according to the situation of the traveled road surface. It is said that the applied voltage amount of is appropriately adjusted.

Therefore, in the shock absorber using the electrorheological fluid according to this embodiment formed as described above, the rod side chamber A is operated when the shock absorber in which the piston rod 2 is retracted from the cylinder 1 is extended and retracted. The electrorheological fluid in the above state flows into the piston side chamber B via the control gap S, the reservoir chamber R2 and the base valve portion 14. That is, the electro-rheological fluid from the rod side chamber A always flows through the control gap S during the expansion and contraction operation of the shock absorber, and functions as a so-called one-way type.

Then, the surplus electrorheological fluid in the rod side chamber A during the pressure side operation of the shock absorber is the control gap S.
The electrorheological fluid that flows into the reservoir chamber R2 via the base valve portion 14 and is deficient in the piston side chamber B during the expansion side operation of the shock absorber is replenished from the reservoir chamber R2 via the base valve portion 14.

When a predetermined voltage is applied to the cylinder 1 which is one of the electrode members and the inner tube 10 which is the other of the electrode members during the expansion and contraction operation of the shock absorber, the control gap S formed between the two electrode members. An electric field is developed in. The expression of the electric field results in that the viscosity of the electrorheological fluid interposed there, that is, the viscosity of the electrorheological fluid flowing therethrough, is instantaneously changed to a hardening tendency, and therefore the electrorheological fluid with the changed viscosity After that, the fluid acts so as to prevent the electrorheological fluid from flowing through the control gap S.

As a result, the outflow of the electrorheological fluid from the rod side chamber A is hindered, and the slidability of the piston portion 3 in the cylinder 1 is hindered, which is manifested as a damping action. Of the piston rod 2 into the cylinder 1 and the piston rod 2 in the cylinder 1
The protrusion from the inside is hindered, and the shock absorber functions as a so-called shock absorber.

Therefore, if the applied voltage amount is appropriately controlled,
It becomes possible to immediately perform the damping action according to the applied voltage amount and smoothly perform a predetermined damping force adjustment without any steps.
When the shock absorber is mounted on an automobile, the damping action can be adjusted according to the condition of the road surface of the automobile, and the riding comfort of the automobile can be improved to a preferable state.

It should be noted that a plurality of inner tubes may be provided so as to be of a multiple type, the control gap may be lengthened, and a large fluid resistance may not be generated in the vicinity of the ports opening to the rod side chamber and the reservoir chamber.

[0042]

As described above, the present invention has the following effects.

By appropriately controlling the applied voltage amount, it becomes possible to immediately and smoothly execute a predetermined damping action. When this is used as a shock absorber mounted on an automobile, the traveling road surface of the automobile can be controlled. The damping force can be adjusted according to the situation, and the riding comfort of the automobile can be improved satisfactorily.

Since the control gap is formed inside the so-called shock absorber so that the impact from the outside does not directly act, the external force such as the impact on the outer periphery of the electrode member forming the control gap can be blocked in advance. As a result, the control gap can be maintained as set.

Both electrode members are not exposed to the outside, and electric shock and leakage are prevented.

Since the cylinder and the inner tube are insulated from each other at their ends, leakage does not occur through the other members such as bearings, regardless of whether the current is direct current or alternating current. Power loss can be prevented.

[Brief description of drawings]

FIG. 1 is a sectional view showing a shock absorber using an electrorheological fluid according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a shock absorber using an electrorheological fluid as a conventional example.

[Explanation of symbols]

 1 Cylinder 3 Piston part 3a Extension side check valve 8 Insulation material 10 Inner tube 11 Outer tube 14 Base valve part 14c Pressure side check valve A Rod side chamber B Piston side chamber R2 Reservoir chamber S Control clearance

Claims (1)

[Claims] 1. An inner tube is provided outside the cylinder, an outer tube is provided outside the inner tube, and a reservoir chamber is formed between the inner tube and the outer tube. Further, a piston is provided inside the cylinder. Part is slidably accommodated to partition and form a rod side chamber and a piston side chamber in the cylinder, while the piston side chamber is communicated with the rod side chamber via an extension side check valve in the piston part, and the cylinder and the inner tube are connected. A control gap that communicates with the rod side chamber and the reservoir chamber is formed between
Further, the reservoir chamber is communicated with the piston side chamber through the pressure side check valve in the base valve portion arranged at the lower end of the cylinder, and the both ends of the cylinder and the inner tube are connected to the bearing and the base through the insulating material. A shock absorber, characterized in that it is connected to a valve body of a valve, and a cylinder is used as one electrode member while an inner tube is used as the other electrode member.