KR101217277B1 - Shock absorber with its lag restraint - Google Patents

Abstract

The present invention relates to a shock absorber, comprising providing a shock absorber configured to reduce or suppress a "lag" phenomenon in a compression chamber caused by a delay in opening of a flow path of a base valve and thus negative pressure generation of the compression chamber. For that purpose.

To this end, the shock absorber according to the present invention, the inner passage is formed by the upper and lower moving piston valve, the inner rebound chamber and the lower compression chamber; An outer cylinder provided outside the inner cylinder to form a reservoir chamber in which gas and oil are filled between the inner cylinder; A base valve formed at a portion where the inner cylinder and the outer cylinder are connected, and allowing oil flow between the reservoir chamber and the compression chamber according to the vertical movement of the piston valve; An oil replenishment flow passage provided on the side of the inner cylinder to further allow oil flow from the reservoir chamber to the compression chamber when the piston valve is raised.

Lag, Shock Absorber, Oil, Compensation, Compression, Rebound, Negative Pressure

Description

Shock absorber that lag is suppressed {SHOCK ABSORBER WITH ITS LAG RESTRAINT}

1 is a cross-sectional view showing a shock absorber according to an embodiment of the present invention, an enlarged view of the main parts.

FIG. 2 is a view for explaining the oil exchange action between the compression chamber and the reservoir chamber in the shock absorber shown in FIG. 1; FIG.

<Code Description of Major Parts of Drawing>

120: piston valve 140: inner cylinder

160: outer cylinder 180: base valve

190: oil supplement valve 192: oil supplement flow path

R: Rebound Chamber C: Compression Chamber

P: reservoir chamber

The present invention relates to a shock absorber of the present invention, and more particularly, to a shock absorber having a structure capable of suppressing or reducing a phenomenon in which negative pressure is temporarily generated under a piston valve, that is, a "lag".

The shock absorber is installed on the vehicle body, and supports the weight of the vehicle body and reduces the vibration transmitted from the road surface to the vehicle body. In addition, the shock absorber absorbs the up and down vibration energy of the wheels (wheels) due to irregularities in the road, thereby contributing to the improvement of the passenger comfort, the protection of the loaded cargo, and the protection of each part of the vehicle.

 Typically, the shock absorber includes a cylinder connected to the wheel side and a piston rod connected to the vehicle body side. The inside of the cylinder is filled with oil, and the piston rod is connected to a piston valve that divides the inside of the cylinder into a rebound chamber and a compression chamber. The piston valve includes a rebound flow path and a compression flow path connecting the rebound chamber and the compression chamber, and when the piston valve moves, oil passes through the flow path described above to generate a predetermined damping force.

On the other hand, a pressure change occurs in the compression chamber generated when the piston valve is moved, in order to cope with such pressure change, the shock absorber is composed of a structure to compensate the pressure in the compression chamber. In addition, the shock absorber is classified into a telescopic shock absorber having a single cylinder and a twin tube shock absorber having a double structure of an inner cylinder and an outer cylinder according to a pressure compensating structure.

The conventional twin tube type shock absorber is divided into a rebound chamber and a compression chamber by a piston valve while the inner cylinder is filled with oil, and a reservoir chamber in which gas and oil are filled inside the outer cylinder surrounding the inner cylinder. Is formed. And, a portion of the inner cylinder and the outer cylinder is connected to the base valve is mainly provided for generating a damping force when the piston descends, that is, when the compression stroke of the shock absorber occurs. A flow path connecting the reservoir chamber and the compression chamber is formed in the base valve, and the pressure in the compression chamber of the shock absorber may be compensated for by the oil flowing from the reservoir chamber to the compression chamber through the flow path.

However, the conventional shock absorber has a problem in that a "lag" phenomenon occurs under the piston valve, that is, in the compression chamber when the piston valve is raised by the rebound stroke. This "lag" phenomenon is caused by a delay in the flow of oil from the reservoir chamber back to the compression chamber when the oil which has flowed into the reservoir chamber by the compression stroke of the shock absorber is converted from the compression stroke to the rebound stroke. . This "lag" phenomenon causes significant distortion of the damping force in the compression section of the shock absorber. In order to prevent this "lag" phenomenon, expanding the cross-sectional area of the flow path of the base valve has been considered. However, there has been a big limitation in increasing the cross-sectional area of the flow passage from the reservoir chamber to the compression chamber in a base valve having a predetermined area requiring a flow path in both directions.

It is therefore an object of the present invention to provide a shock absorber configured to reduce or suppress the " lag " phenomenon in the compression chamber caused by the delay of opening of the flow path of the base valve and thus the negative pressure generation of the compression chamber.

The shock absorber according to the present invention for achieving the above object is provided with an inner cylinder formed of an upper rebound chamber and a lower compression chamber by a piston valve moving up and down, and provided on an outer side of the inner cylinder. An outer cylinder which forms a reservoir chamber filled with gas and oil between the inner passage, and is formed at a portion where the inner cylinder and the outer cylinder are connected, and an oil flow between the reservoir chamber and the compression chamber as the piston valve moves up and down; A base valve for allowing oil to flow and an oil replenishment flow path provided on the side of the inner cylinder to further allow oil flow from the reservoir chamber to the compression chamber when the piston valve is raised.

Here, the oil replenishment flow passage is preferably provided with an oil replenishment valve configured to open the oil replenishment flow passage only when the piston valve is raised, wherein the oil replenishment valve includes: a first hole formed at a side of the inner cylinder; A valve cover attached to an outer side of the inner cylinder to cover the first hole at the same time as having a second hole for forming the oil replenishing flow passage, and installed to be movable within the valve cover, and the piston valve being raised And a valve plate member for opening said second hole which forms said oil replenishing flow path.

Example

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

1 shows a shock absorber according to an embodiment of the present invention. As shown in FIG. 1, the shock absorber 100 according to the present embodiment includes a piston valve 120, an inner cylinder 140 accommodating the piston valve 120, and an inner cylinder 140. It includes an outer cylinder 160 installed to surround. Then, the base valve 180 is installed in the portion connecting them at the lower end of the inner cylinder 140 and the outer cylinder 160. The rod guide 102 is installed at the upper ends of the inner cylinder 140 and the outer cylinder 160, and the piston rod 110 is slidably installed at the rod guide 102. The piston rod 110 is connected to the piston valve 120 in the inner cylinder 140. In addition, the shock absorber 100 further includes an oil supplement valve 190 used for pressure compensation of the compression chamber C together with the base valve 180. It will be described in more detail.

The inner cylinder 140 is filled with oil, and the upper and lower portions of the inner cylinder 140 are divided into a rebound chamber (R) and a compression chamber (C) by the piston valve 120. do. In addition, a reservoir chamber P filled with gas and oil to form an upper and a lower layer is formed between the inner cylinder 140 and the outer cylinder 160. The base valve 180 is formed between the reservoir chamber P and the compression chamber C while forming a boundary.

Referring to the enlarged view "A" of FIG. 1, the piston valve 120 includes a valve body 121 in which a rebound flow passage 121a and a compression flow passage 121b are formed. In addition, the piston valve 120 is provided with valve disks 122a and 122b provided at the lower and upper ends of the valve body 121 so as to open the rebound flow path 121a and the compression flow path 121b only by their rising and lowering. It includes.

When the piston valve 120 is raised in accordance with the rebound stroke, the valve disks 122a located at the bottom of the valve body 121 are bent and deformed due to the increase in the oil pressure in the rebound chamber R. The closed rebound flow passage 121a is opened. At this time, the shock absorber generates a predetermined damping force in the rebound section by oil passing through the rebound flow passage 121a while bending the valve discs 122a.

In addition, when the piston valve 120 is lowered according to the compression stroke, one valve disk 122b is flipped as the pressure in the compression chamber C increases, and the compression passage 121b is opened. The oil may flow from the compression chamber C to the rebound chamber R through the compression passage 121b.

In response to the above-described rebound stroke and compression stroke, the base valve 180 is configured to exchange oil between the compression chamber C and the reservoir chamber P in accordance with the vertical movement of the piston valve 120. Referring to the enlarged view “B” of FIG. 1, the base valve 180 includes a valve body 181, and first and second fixed passages 181a and 181b are formed in the valve body 181. have. The first fixed passage 181a is closed by a plurality of valve disks 182a located at the bottom of the valve body 181, which are connected to the compression stroke and the piston valve 120. It is configured to open the first fixed passage 181a while being warped and deformed by an increase in the oil pressure of the compression chamber C according to the lowering. At this time, the oil passes through the first fixing channel 181a while bending and deforming the valve disks 182a, thereby generating a predetermined damping force in the compression section of the shock absorber. In addition, the second fixed flow path 181b is closed by one valve disks 182b located on the upper end of the valve body 181, and the valve disk 182b is rebounded according to the rise of the piston valve 120. It is configured to open the first fixed passage 181b while being turned over.

When there is a rebound stroke, that is, when the piston valve 120 rises, the pressure drops below the piston valve 120, that is, in the compression chamber C. Accordingly, oil in the reservoir chamber (P) flows into the compression chamber (C) while opening the second fixed passage (181b) of the base valve (180). The pressure in the compression chamber C can be compensated for. However, a significant delay inevitably occurs in the flow of oil from the reservoir chamber P to the compression chamber C, especially when the rapid return from the compression stroke to the rebound stroke is made. . This delay results in a phenomenon commonly referred to as "lag" in the compression chamber (C), which causes cavitation in the compression chamber (C) and also in subsequent compression strokes. Cause severe distortion.

The shock absorber 100 according to the present invention is an oil replenishment flow path for replenishing oil to the compression chamber C without passing through the base valve 180 from the reservoir chamber P to suppress the above "lag" phenomenon ( 192 (indicated by arrows). In the present embodiment, the oil replenishment flow passage 192 is provided with an oil replenishment valve 190 which will be described in detail below. The opening 192 is configured to close the oil replenishment flow passage 192 so as not to affect the damping force of the shock absorber during the compression stroke.

Hereinafter, the structure of the oil replenishment valve 190 according to a preferred embodiment of the present invention will be described, but the oil replenishment valve 190 has various structures that can replenish oil into the compression chamber C only during the rebound stroke. It may be made of a valve (eg, check valve, relief valve, etc.).

Referring to the enlarged view "C" of FIG. 1, a first hole 192a is formed in the side surface of the inner cylinder 140. The oil fill valve 190 includes a valve cover 193 having a second hole 192b that forms an oil fill channel 192 together with the first hole 192a. In addition, the valve cover 193 is attached to the inner cylinder 140 to cover the first hole 192a. In addition, a valve plate member 194 is slidably installed in the valve cover 193 by oil pressure, and the valve plate member 194 is changed by a pressure change when the piston valve 120 is raised. The oil refill passage 192 is opened by opening the second hole 192b while slidingly moving in the valve cover 193.

The valve plate member 194 includes, on the outer circumferential surface, a pair of orifices 194a and 194b forming the oil replenishment flow passage 192 together with the above-described holes 192a and 192b. In addition, the front surface of the valve plate member 194 has a circular shape for blocking the second hole 192b of the valve cover 193 from the oil replenishment flow passage 192 in contact with the inner surface of the valve cover 193. A blocking protrusion 194c is formed.

In addition, the valve plate member 194 is slidably moved to the position where the blocking protrusion 194 closes the oil replenishment flow passage 192 due to the pressure change according to the compression stroke of the shock absorber. Block the flow of oil between the reverser chamber (R) (see Figure 2 (a)). In addition, the valve plate member 194 is integrally provided with a circular spacer protrusion 194d contacting the outer surface of the inner cylinder 140 and spaced apart between the valve plate member 194 and the inner cylinder 140. An orifice 194e is formed in the circular spacer protrusion 194d to allow flow of oil through the oil replenishment flow passage 192 from the rebound chamber P to the compression chamber C in the rebound stroke.

In the rebound stroke of the valve plate member 194 shock absorber, the spaced protrusion 194e is moved to a position in contact with the outer surface of the inner cylinder 140 due to the pressure change, and the oil is replenished by the spaced gap in the position. The flow path 194 may be kept open (see FIG. 2B).

2 (a) and 2 (b) are conceptual views for explaining the oil exchange action between the reservoir chamber C and the compression chamber R in the compression stroke and the rebound stroke of the shock absorber. In FIG. 2, components such as the base valve and the piston valve of the shock absorber are omitted for convenience.

In the compression stroke shown in FIG. 2A, the oil in the compression chamber C flows into the reservoir chamber P as the pressure in the compression chamber C increases. At this time, the oil is made only through the flow path of the base valve 180 (see FIG. 1), which is not shown in FIG. 2A, and the oil replenishment valve 190 described above is connected to the valve plate member 194. Since 192 is blocked, the flow of oil through the oil replenishment flow passage 192 is not made.

On the other hand, in the rebound stroke shown in FIG. 2B, the oil in the reservoir chamber P flows into the compression chamber C as the pressure in the compression chamber C decreases, and the pressure in the compression chamber C is reduced. To compensate. At about the same time, the valve plate member 194 of the oil refill valve 190 described above is moved to open the oil replenishment flow passage 192, thereby adding an additional portion between the reservoir chamber P and the compression chamber C. FIG. Oil compensation path is formed. By the addition of such an oil compensation path, the delay of the oil flow from the reservoir chamber P to the compression chamber C can be suppressed.

While the present invention has been particularly shown and described with reference to specific embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the present invention as defined by the appended claims. And should not be construed as limiting the scope of the present invention, but rather should be construed as exemplifying the invention.

According to the embodiment of the present invention, during the rebound stroke of the shock absorber, it prevents the "lag" phenomenon in which the oil flow from the reservoir chamber to the compression chamber is delayed, and the damping force in the compression stroke caused by the "lag" phenomenon is prevented. It can suppress the distortion.

Claims (3)

An inner passage formed of an upper rebound chamber and a lower compression chamber by an upward and downward moving piston valve; An outer cylinder provided outside the inner cylinder to form a reservoir chamber in which gas and oil are filled between the inner cylinder; A base valve formed at a portion where the inner cylinder and the outer cylinder are connected, and allowing oil flow between the reservoir chamber and the compression chamber according to the vertical movement of the piston valve; An oil replenishment flow passage provided on the side of the inner cylinder to further allow oil flow from the reservoir chamber to the compression chamber when the piston valve is raised, The oil replenishment flow passage is provided with an oil replenishment valve configured to open the oil replenishment flow passage only when the piston valve is raised. The oil fill valve includes a valve cover attached to an outer side of the inner cylinder to cover the first hole while having a second hole forming the oil replenishing flow path together with a first hole formed on a side of the inner cylinder; And a valve plate member installed to be movable within the valve cover and opening the second hole forming the oil replenishment flow path when the piston valve is raised. delete delete

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