JPH0650375A - Buffer device - Google Patents

Abstract

PURPOSE:To control the damping force to a constant value or different value by allowing a rod side chamber and a piston side chamber to communicate through an extension side control gap and allowing the piston side chamber and a reservoir chamber to communicate through a pressure side control gap. CONSTITUTION:During the extension/contraction operation of a buffer device, the electric viscous fluid in a rod side chamber A flows into a piston side chamber B through each control gap S1, S2 reservoir chamber R2, and a base valve part 14. When a prescribed voltage is applied to the cylinder 1 and the inner tube 10b of one electrode member and the inner tube 10a of the other electrode member, each electric field is generated in the control gas S1 and S2 between the electrode members, and the viscosity of the electric viscous fluid which flows in the electric field changes instantly to increase, and acts so as to obstruct the flow of the electric viscous fluid in the electric field. Accordingly, the sliding of a piston part 3 in the cylinder 1 is prevented, and the damping action can be adjusted by properly controlling the applied voltage quantity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic shock absorber, or a shock absorber capable of adjusting a generated damping force by utilizing a 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.

Therefore, in the hydraulic shock absorbers conventionally proposed for that purpose, in general, when the piston portion slides in the cylinder by retracting the piston rod with respect to the cylinder, A predetermined damping force is generated by the hydraulic fluid passing through the damping force generation unit, and the mechanism of the damping force generation in the damping force generation unit is mechanically changed or passes through the damping force generation unit. It is configured so that the generated damping force can be adjusted to high or low by increasing or decreasing the flow rate of hydraulic oil.

As a result, when the damping force generating section is constituted by 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 various throttles, valves, etc. so as to be able to exert damping force of 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.

Therefore, in recent years, an electrorheological fluid having a property that its viscosity changes with an applied voltage has been discovered, and for example, it is shown in FIG. 3 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 part 3 which moves and which partitions and forms a rod 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 chambers A and B communicate with the outside through the ports 1a and 1b, respectively. .

A reservoir tank T is disposed 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 through the pipe P.

On the other hand, it is assumed that 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 communicated with the side chambers A and B through the ports 1a and 1b for opening the cylinder 1.

The head-side tubular body 4 has a bearing member 7 screwed onto the inner periphery of its upper end, and a piston rod 2 is slidably inserted in the center 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 via 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 wall thickness 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 its upper and lower ends, 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 periphery thereof and the outer periphery of the cylinder 1 so that a part of the chamber R is so-called 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 in accordance with the applied voltage amount when the electric field is developed therein.

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 that is connected to the upper end side tubular body 4 that is electrically connected to the cylinder 1 and that extends from the controller C is connected to the intermediate portion 6 which is the other electrode member.

Therefore, according to the shock absorber using the electrorheological fluid as the conventional proposal, 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, the damping action is announced, and the degree of the damping action to be announced can be arbitrarily set by appropriately selecting the applied voltage amounts to both electrode members. Can be adjusted to.

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

[0025]

However, in the shock absorber using electrorheological fluid as the conventional example shown in Japanese Utility Model Publication No. 3-5698, the same control is performed on the extension side and the compression side. Since the gap S is used, it is difficult to separately control the damping force generated during extension and during compression.

In order to change this, it is necessary to change the applied voltage at the time of expansion and at the time of compression. At this time, it is not known from the outside whether it is in the extension stroke or the pressure stroke, so this is detected. It requires a sensor to operate, which increases cost.

The present invention was devised in view of the above-mentioned circumstances, and its purpose is to automatically and freely set the extension side damping force and the compression side damping force so as to be the same or different. The purpose is to provide a shock absorber that can be manufactured at low cost.

[0028]

To achieve the above object, the structure of the present invention is such that a piston rod is movably inserted into a cylinder via a piston portion, and the rod side chamber and the piston are inserted into the cylinder by the piston portion. In the shock absorber in which the two chambers are partitioned from each other, the two oil chambers are connected to each other through the first check valve provided in the piston portion and opened at the time of compression, and the reservoir chamber is defined outside the cylinder. The piston side chamber is communicated with the expansion side control gap, the piston side chamber is communicated with the reservoir via the pressure side control gap, and the piston side chamber and the reservoir chamber are communicated with each other via a second check valve opened at the time of extension. The expansion side control gap and the compression side control gap are separated by an electrode member consisting of a cathode and an anode, and the inlet and outlet of the expansion side control gap are the third and fourth checkers that are opened during extension. Valve openably provided, the inlet of the compression side control gap is characterized in that the fifth check valve that opens when pressure side is provided so as to be freely opened and closed.

[0029]

In the extension and the compression, the expansion side control gap and the compression side control gap respectively flow, so that independent damping forces are generated in the respective gaps, and the magnitude of the damping force is applied to the electrode members that control the respective gaps. It is controlled by the applied voltage.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail based on the illustrated embodiments. The embodiment shown in FIG. 1 is a shock absorber using an electrorheological fluid for automobiles. , Cylinder 1 and two inner tubes 10a,
10b and the outer tube 11, and is formed into a so-called quadruple cylinder type as opposed to a so-called double cylinder type. The shock absorber may be a multiple-type hydraulic shock absorber including an ordinary triple cylinder.

The cylinder 1 shown in FIG. 1 is formed in a so-called single tube structure in which a piston rod 2 is inserted in a retractable manner, and is partitioned and formed by a piston portion 3 slidably accommodated therein. And a rod side chamber A and a piston side chamber B.

The rod-side chamber A and the piston-side chamber B are 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 includes inner tubes 10a, 1a.
The upper end of 0b is also closed under the distribution of the insulating material 8.

The bearing member 12 is the seal member 1.
It is connected to the inner periphery of the lower end side of the cap member 13 which holds 6 and allows the piston rod 2 to be inserted.

The cap member 13 has its lower end connected to 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.

The valve body 14a closes the lower end of the inner tube 10 under the insulating material 8a. The valve body 14a is assumed to be supported in a state of being connected to a bottom member 15 disposed below the valve body 14a, and the bottom member 15 has the lower end of the outer tube 11 continuously connected to the upper end side thereof. .

The base valve portion 14 is a valve body 14
The port 14b opened in a and the second pressure side check valve 1 arranged so as to close the upper end side of the port 14b.
4c through the piston side chamber B to the inner tube 10b
The reservoir chamber R2 is formed between the outer tube 11 and the outer tube 11. The check valve 14c opens on the extension side.

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 first extension side check valve 3a that is arranged so as to close the upper end side of the port 3d. The first check valve 3d opens during compression.

On the other hand, a port 1a is formed in the bearing member 12 and the insulating material 8, and ports 1b and 1c are formed in the lower valve body 14a and the insulating material 8a. The ports 1a and 1b are the cylinder 1 and the inner tube 10.
They communicate with each other through an expansion side control gap S1 formed between a and a.

The port 1c is the inner tube 10a, 1
0b and the pressure side control gap S2 formed between the pipe 1 and
It is connected to the reservoir R2 via 8.

The control gap S1 is opened and closed by the rod side chamber A through a third check valve 19 which is opened when the port 1a on the inlet side is extended, and the fourth check valve 19 in the port 1b which is also on the outlet side is opened. It is opened and closed by the piston side chamber B via.

The control gap S2 is opened and closed by the piston side chamber B via a fifth check valve 21 which opens at the time of compression in the port 1c which is the inlet.

By the way, the expansion side and compression side control gaps S1,
In order to make S2 speak the electric field, a predetermined voltage is applied to both the positive electrode member and the negative electrode member. In this embodiment, however, one of the cylinders is used as an anode electrode member. 1 and the inner tube 10b are set on the plus side, for example, and the inner tube 10a serving as the electrode member of the other cathode is set on the minus side.

Then, the cylinder 1 and the inner tube 1
0b is connected with an electric wire E1 extended from an external controller C or a power source, and the inner tube 10
It is assumed that the electric wire E2 extended from the controller C is connected to a.

The wires E1 and E2 are the outer tube 1
In the case of penetrating through No. 1, the insulating material which is inserted into the insertion hole opened in the outer tube 11 under the liquid tight state is penetrated under the liquid tight state. The electric wires E1 and E2 are connected while penetrating the inner tubes 10a and 10b while being insulated.

The connection method is not limited to this. Further, the control gaps S1 and S2 are provided in the outer tube 11
Alternatively, a pipe or a hose formed of an electrode member may be formed outside the.

In this embodiment, the controller C receives the signal from the vehicle height sensor C1 mounted on the automobile, and when the shock absorber is mounted on the automobile and travels on the road, It is said that the amount of voltage applied to both electrode members is appropriately adjusted according to the condition of the traveling road surface.

Therefore, in the shock absorber using the electrorheological fluid according to this embodiment, which is formed as described above, when the shock absorber in which the piston rod 2 is retracted with respect to the cylinder 1 is expanded and contracted, the rod side chamber A is placed in the chamber A. A certain electrorheological fluid will flow into the piston side chamber B via the control gaps S1 and S2, the reservoir chamber R2 and the base valve portion 14.

That is, in the shock absorber, during the expansion and contraction operation, the electrorheological fluid from the rod side chamber A is always provided with the control gap S.
1 and S2 will be distributed, and it will function as what is called a one-way type.

The surplus electrorheological fluid in the rod side chamber A during the pressure side operation of the shock absorber is the control gap S2.
The electrorheological fluid that flows into the reservoir chamber R2 via the and is insufficient in the piston side chamber B during the expansion side operation of the shock absorber,
It is replenished from the reservoir chamber R2 via the base valve portion 14.

That is, at the time of extension, the electrorheological fluid in the rod side chamber A flows out to the piston side chamber B through the third check valve 19-port 1a-controlling gap S1-port 1b-fourth check valve 20, and The discharged volume of fluid is replenished to the piston side chamber B from the reservoir R2 via the port 14b and the second check valve 1b.

On the other hand, during compression, a part of the fluid in the piston side chamber B flows out to the rod side chamber A via the first check valve 3a and to the reservoir R2 via the port 1c and the fifth check valve 21.

When a predetermined voltage is applied to the cylinder 1 and the inner tube 10b, which are one of the electrode members, and the inner tube 10a, which is the other electrode member, when the shock absorber expands and contracts, it is formed between both electrode members. An electric field is developed in the control gaps S1 and S2.

The expression of the electric field causes the viscosity of the electrorheological fluid interposed therein, that is, flowing therethrough, to be instantly changed to a hardening tendency, and therefore the viscosity is changed. The electrorheological fluid will be hereafter referred to as the control gaps S1, S2.
Acts to prevent the flow of the electrorheological fluid.

As a result, the outflow of the electrorheological fluid from the rod side chamber A is hindered, and the slidability of the piston part 3 in the cylinder 1 is hindered, which is stated 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 ride comfort of the automobile can be improved to a preferable state.

A plurality of inner tubes may be provided to form a multiple type, and the width of the control gap may be widened or the length may be long, narrow or short.

FIG. 3 shows another embodiment. This forms ports 22 and 24 in the piston part 3 and the base valve 14, and in the middle of each port 22 and 24, damping force generating parts 23 and 2 which consist of an orifice, a leaf valve, or a combination thereof.
5 is provided. In this embodiment, the degree of freedom in setting the damping force increases. The other structure is the same as that of the embodiment of FIG.

[0060]

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

Since the rod side chamber and the piston side chamber communicate with each other through the expansion side control gap, and the piston side chamber and the reservoir chamber communicate with each other through the compression side control gap, the expansion side damping force and the compression side damping force are respectively generated. Independently controlled via the control gap.

Therefore, the magnitude of the damping force can be the same or different.

Moreover, since a sensor for detecting the pressure stroke and the extension stroke is not necessary, the cost can be reduced.

When the cylinder and the inner tube are electrode members, since the fluid is a shock absorber using an electrorheological fluid, the amount of applied voltage is appropriately controlled to immediately and smoothly perform a predetermined damping action. When this is used as a shock absorber mounted on an automobile, the damping force can be adjusted according to the condition of the road surface of the automobile, and the riding comfort of the automobile can be improved satisfactorily. It will be.

When the control gap is formed by the cylinder and the inner tube so that the external impact does not act directly, 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, and both electrode members are not exposed to the outside, so that electric shock or leakage is prevented. Furthermore, if the ends of the cylinder and the inner tube are insulated, no current will flow through other members such as bearings to other members regardless of whether the current is DC or AC, and leakage is prevented and power loss is prevented. It 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 of a shock absorber according to another embodiment.

FIG. 3 is a sectional view showing a shock absorber using an electrorheological fluid as a conventional example.

[Explanation of symbols]

 1 Cylinder 2 Piston rod 3 Piston part 3a First check valve 8,8a Insulating material 10a, 10b Inner tube which is an electrode member 11 Outer tube 14 Base valve part 14c Second check valve 19 Third check valve 20 Fourth Check valve 21 Fifth check valve A Rod side chamber B Piston side chamber R2 Reservoir chamber S1 Extension side control gap S2 Pressure side control gap

Claims (1)

[Claims] 1. A piston rod is movably inserted into a cylinder via a piston part, and a rod part chamber and a piston side chamber are partitioned by the piston part in the cylinder, and two oil chambers are provided in the piston part. In a shock absorber which is communicated through a first check valve which is opened at the time of compression and has a reservoir chamber defined outside the cylinder, a rod side chamber and a piston side chamber are communicated with each other through an expansion side control gap, and a piston The side chamber and the reservoir are communicated with each other through the pressure side control gap, the piston side chamber and the reservoir chamber are communicated with each other through a second check valve which is opened during extension, and the extension side control gap and the pressure side control gap are connected with the cathode and the anode. The third and fourth check valves that are opened at the time of extension are opened and closed at the inlet and outlet of the expansion side control gap, and the pressure side is provided at the inlet of the pressure side control gap. A shock absorber, which is provided with a fifth check valve that opens at times so as to be openable and closable.