KR100819425B1 - Shock absorber having self pumping unit - Google Patents

Abstract

A shock absorber having a self-pumping unit is provided to compensate for the lack of air in a reservoir chamber by obtaining compression air using energy generated by a reciprocating movement of a piston rod. A shock absorber having a self-pumping unit comprises an inner sleeve(140), which is divided into a rebound chamber(R) and a compression chamber(C), and an outer sleeve(160) which has a reservoir chamber(P) for supplying oil to the compression chamber during a rebound stroke and collecting oil during a compression stroke. A high-pressure tank(170) is installed at a lower side of the outer sleeve and has a high-pressure chamber(172), which communicates with the reservoir chamber through a two-direction valve. The self-pumping unit sucks outside air and then pumps out the air to the high pressure chamber by utilizing energy formed when a piston rod reciprocates.

Description

Shock absorber with self-pumping unit {SHOCK ABSORBER HAVING SELF PUMPING UNIT}

1 is a schematic diagram schematically showing a shock absorber according to an embodiment of the present invention.

2 and 3 are views for explaining the operation of the shock absorber according to an embodiment of the present invention.

4 is a view for explaining a control concept of the shock absorber according to an embodiment of the present invention.

<Description of Signs of Major Parts of Drawings>

120: piston valve 130: self pumping unit

140: inner cylinder 150: electronic control unit

160: outer cylinder 180: body valve

The present invention relates to a shock absorber, and more particularly, to a shock absorber provided with a self-pumping unit below the outer cylinder, which can obtain a compressed gas by itself using energy from vertical movement of the piston rod. Specifically, the compressed gas obtained from the self-pumping unit is selectively supplied to the reservoir chamber, whereby a negative pressure is generated temporarily below the piston valve when changing from, for example, a compression stroke to a rebound stroke, that is, "lag" lag) &quot;.

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.

In the case of a twin-tube shock absorber, the inner chamber is filled with oil and divided into a rebound chamber and a compression chamber by a piston valve, and a reservoir chamber in which gas and oil are filled inside the outer cylinder surrounding the inner cylinder. Is formed. And, the body valve is installed in the portion where the inner cylinder and the outer cylinder is connected. The body valve is formed with a flow path connecting the compression chamber and the reservoir chamber. When the piston valve rises, that is, during the rebound stroke of the shock absorber, the oil flows from the reservoir chamber to the compression chamber through the flow path. The pressure in the compression chamber of the absorber can be compensated. When the piston valve is lowered, that is, when the compression stroke of the shock absorber occurs, the body valve mainly produces a damping force.

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 such a "lag" phenomenon, expanding the flow path cross-sectional area of the body valve has been considered. However, there is a limitation in increasing the cross-sectional area of the flow passage from the reservoir chamber to the compression chamber in a body valve having a predetermined area requiring a flow path in both directions.

In addition, the conventional shock absorber may not supply enough oil into the compression chamber in the rebound stroke because the gas pressure in the own chamber chamber falls below a certain value as the service life becomes longer, which also prevents the damping force distortion. It could be one cause of the "lag" causing it.

Accordingly, an object of the present invention is a shock absorber configured to suck external gas (air) as the piston rod moves up and down to obtain a compressed gas by itself, and to use the obtained compressor body for suppressing the "lag" phenomenon of the shock absorber. To provide.

In order to achieve the above object, the present invention, the piston valve is connected to one end of the piston rod which is accommodated inside the inner cylinder and moves in the rebound stroke and the compression stroke, the inner cylinder inside the rebound chamber and the compression by the piston valve In the shock absorber is formed in the chamber, the outer cylinder outside the inner cylinder is provided on the lower side of the outer cylinder in the reservoir chamber is formed with a reservoir chamber for supplying oil to the compression chamber in the rebound stroke and recovering oil in the compression stroke. A high pressure tank having a high pressure chamber in both directions communicated with the reservoir chamber by selectively opened bidirectional valves; A self-pumping unit that pumps the external gas by pumping the external gas by using the energy generated by the vertical movement of the piston rod; It is comprised to include.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. In the accompanying drawings, components of the shock absorber are omitted or schematically illustrated for better understanding of the invention.

1 is a schematic diagram of a shock absorber according to an embodiment of the present invention. As shown, the shock absorber 100 according to the present embodiment, the piston valve 120, the inner cylinder 140 for receiving the piston valve 120 therein, and installed so as to surround the inner cylinder 140 It includes an outer cylinder 160. A body valve 180 is installed at the lower end of the inner cylinder 140 to connect 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 installed to the rod guide 102 so as to seal sealingly. The piston rod 110 is connected to the piston valve 120 in the inner cylinder 140.

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) is formed between the inner cylinder 140 and the outer cylinder 160 such that gas and oil form upper and lower layers. In addition, the body valve 180 described above forms a boundary between the reservoir chamber P and the compression chamber C.

The piston valve 120 includes a valve body 121 in which a rebound flow path and a compression flow path are formed. In addition, the rebound flow path and the compression flow path are provided with a rebound valve element 122a and a compression valve element 122b that open the rebound flow path and the compression flow path in opposite directions as the piston valve 120 moves. . Typically, the rebound valve element 122a includes a plurality of valve discs that open while generating a desired damping force by oil pressure in the rebound stroke, and the compression valve element 122b is compressed from the rebound chamber in the compression stroke. It consists of at least one valve disc which opens to allow oil flow into the chamber.

When the piston valve 120 is raised in accordance with the rebound stroke, the rebound valve element 122a opens the rebound flow path by increasing the oil pressure in the rebound chamber R, and the oil passes through the open rebound flow path. The shock absorber 100 generates a predetermined damping force in the rebound section. In addition, when the piston valve 120 is lowered according to the compression stroke, the compression valve element 122b opens the compression flow path as the pressure in the compression chamber C increases, thereby opening the opened compression flow path. Through this, the flow of oil from the compression chamber C to the rebound chamber R is allowed.

In response to the rebound stroke and the compression stroke described above, the body 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. The body valve 180 includes a valve body 181, and first and second body flow paths are formed in the valve body 181. The first body flow path is closed by a first body valve element 182a, which is the oil of the compression chamber C in accordance with the compression stroke and the lowering of the piston valve 120. A plurality of valve discs is included to open the first body flow path upon pressure increase. At this time, the oil passes through the first body flow path while bending the valve discs, thereby generating a predetermined damping force in the compression section of the shock absorber. In addition, the second body flow path is closed by a second body valve element 182b including at least one valve disc, which is second body as the piston valve 120 rises. Configured to open the flow path.

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, the oil in the reservoir chamber P flows into the compression chamber C while opening the second body flow path of the body 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.

 According to the exemplary embodiment of the present invention, a high pressure tank 170 in which a high pressure gas is filled is installed below the outer cylinder 160. That is, the high pressure chamber 172 of the high pressure tank 170 is located below the reservoir chamber P.

The shock absorber 100 according to the present embodiment uses the kinetic energy of the piston rod 110 that moves in accordance with the relative movement of the vehicle body and the wheel when installed in the vehicle, and sucks the gas from the outside and absorbs the sucked gas. It includes a self-pumping unit 130 for pumping and filling the high-pressure chamber 172 of the high-pressure tank 170 of its own.

According to the exemplary embodiment of the present invention, the self pumping unit 130 includes a pumping rod 135 connected to the same axis as the piston rod 110. The pumping rod 135 penetrates the lower end of the body valve 180 and the inner cylinder 140 in a sealing manner. A rod guide 112 is installed at the lower end of the body valve 180 and the inner cylinder 140, and the pumping rod 135 slidably penetrates the rod guide 112.

In addition, the self pumping unit 130 includes a pumping chamber 133 to slidably receive the pumping rod 135 to allow the pumping rod 135 to retreat and move forward. The pumping chamber 133 is formed in the pumping block 132 installed inside the high pressure tank 170. Therefore, the pumping chamber 133 is located below the compression chamber C. As shown in FIG.

In addition, the self pumping unit 130 is formed in the pumping block 132 so as to be connected to the pumping chamber 133 and the high pressure chamber 172 of the outside air and the high pressure tank 170, respectively. Two pumping flow paths 134a and 134b. In addition, pumping first and second check valves 136a and 136b are installed in the first and second pumping passages 134a and 134b, and the first and second check valves 136a and 136b are pumped. As the rod 135 retreats and moves forward, the first and second pumping passages 134a and 134b are opened in order.

When the piston rod 110 rises due to the rebound stroke of the shock absorber, the pumping rod 135 connected thereto also rises and retreats in the pumping chamber 133, whereby the pressure in the pumping chamber 133 is caused to flow to the outside atmosphere. Lower than the pressure, the first check valve 136a may open the first pumping passage 134a. Accordingly, atmospheric gas is sucked into the pumping chamber 133 through the first pumping passage 134a. Following the rebound stroke, when the piston rod 110 is lowered by the compression stroke of the shock absorber, the pumping rod 135 connected thereto is also lowered and advanced in the pumping chamber 133, whereby the pumping chamber As the pressure in 133 increases, the second check valve 136b may open the second pumping passage 134a. By opening the second pumping passage 134b, the gas sucked into the pumping chamber 133 in the rebound stroke is pumped and filled into the high pressure chamber 172 of the high pressure tank 170 described above. At this time, when the first pumping passage 134a is opened by the configuration of the first and second check valves 136a and 136b, the second pumping passage 134b is closed and the second pumping passage 134b is closed. It goes without saying that the first pumping passage 134a is closed.

FIG. 2 is a view illustrating an operation of sucking the external gas into the pumping chamber 133 by the self pumping unit 130 as the piston rod 110 rises due to the rebound stroke, and FIG. 3 is a self pumping unit ( 130 is a view for explaining an operation of pumping an external gas from the pumping chamber 133 to the high pressure chamber 172 of the high pressure tank 170 as the piston rod 110 descends due to the compression stroke.

As shown in FIG. 2, when there is a rebounding stroke of the shock absorber in which the pumping rod 135 rises and retracts together with the piston rod 110, the pumping chamber 133 closed by the first and second check valves 136a and 136b. ) Is reduced below atmospheric pressure, whereby the first check valve 136a opens the first pumping passage 134a. Therefore, external gas is sucked into the pumping chamber 133 through the first pumping passage 134a. This is followed by a compression stroke of the shock absorber as shown in FIG.

As shown in FIG. 3, when the pumping rod 135 moves forward together with the piston rod 110, the pressure inside the pumping chamber 133 in which the outside gas is sucked is moved by the pumping rod 135. As a result, the second pumping passage 134b is opened by the second check valve 136b while the first pumping passage 134a is closed. Accordingly, the gas sucked into the pumping chamber 133 is pumped into and flows into the high pressure chamber 172 of the high pressure tank 170 through the opened second pumping passage 134b.

2 and 3 above is performed repeatedly, so that the high pressure chamber 172 in the high pressure tank 170 may be filled with compressed gas. In this case, when the pressure in the high pressure chamber 172 becomes a predetermined pressure or more, it is preferable to exhaust the filled gas to the outside. For this purpose, although not shown, the gas of the high pressure chamber 172 can be exhausted to the outside. It is preferable that a drain valve is provided.

The shock absorber 100, when the pressure in the reservoir chamber (P) by the rebound stroke drops, the high-pressure gas stored in the high-pressure chamber 172 in the high-pressure tank 170 to the reservoir chamber (P). The shock absorber 100 is configured to supplement the pressure dropped in the reservoir chamber P. On the contrary, the shock absorber 100 is reduced in pressure by the aforementioned gas supply from the reservoir chamber P, which has become high pressure by a compression stroke. And recover gas back into the high pressure chamber 172. To this end, bidirectional flow paths are formed between the high pressure chamber 172 and the reservoir chamber P, and these bidirectional flow paths are formed by the first and second valve elements 192 and 194, which are bidirectional valves, which will be described in detail below. Optionally opened and closed, the first and second valve elements 192, 194 are one flow path from the high pressure chamber 172 to the reservoir chamber P in the bidirectional flow path and the high pressure chamber 172 from the reservoir chamber P. Select and open the other flow path leading to). Connecting pipes 193 and 195 are connected to the first and second valve elements 192 and 194, respectively, and an upper end of the connecting pipe 193 is positioned above the reservoir chamber P. Therefore, the high pressure chamber 172 is air circulated in the upper portion of the reservoir chamber (P).

As a method of supplying or recovering the gas filled in the high pressure chamber 172 of the high pressure tank 170 to the reservoir chamber P, various methods may be used, but in the present embodiment, as shown in FIG. 4. Follow the electronic control method.

As described above, the first and second valve elements 192, 194 are provided in bidirectional flow paths between the reservoir chamber P and the high pressure chamber 172. In this case, the first and second valve elements 192 and 194 (hereinafter referred to as “electronic valve elements”) may be configured to be controlled by the electronic control unit 150 as shown in FIG. 4. To this end, the shock absorber 100 according to the present embodiment further includes a pressure sensor 152 that measures the pressure of the reservoir chamber P, and the electronic control unit 150 includes the pressure sensor 152. According to the pressure information measured at, the first and second solenoid valve elements 192, 194 are configured to control.

When the "lag" phenomenon occurs in the rebound stroke of the shock absorber, the electronic control unit 150 determines that the pressure of the reservoir chamber P measured by the pressure sensor 152 has fallen below a predetermined reference value, The first solenoid valve element 192 of the bidirectional valve is opened to supply the high pressure gas of the high pressure chamber 172 in the high pressure tank 170 to the reservoir chamber P. At this time, since the internal pressure of the reservoir chamber P is in response to the rebound stroke, the gas in the high pressure chamber 172 which is in a relatively high pressure state by itself to open the first solenoid valve element 192 is relatively high. It can be quickly supplied into the reservoir chamber (P) in a low pressure state. When gas is replenished in the reservoir chamber P, the oil in the reservoir chamber P passes through the second body channel of the body valve 180 opened by the second body valve element 182b and the compression chamber C. ) Is more quickly supplied to the compression chamber C, so that the "lag" phenomenon due to the oil compensation delay can be suppressed.

When there is a compression stroke subsequent to the rebound stroke, the oil in the compression chamber C is recovered again into the reservoir chamber P via the first body channel of the body valve 180, whereby the reservoir The pressure in the chamber P rises again. The electronic control unit 150 controls to open the second solenoid valve element 194 of the bidirectional valves when the pressure of the reservoir chamber P measured by the pressure sensor 152 is equal to or greater than a predetermined reference value. At this time, since the pressure of the reservoir chamber P is greater than the pressure of the high pressure chamber 172, the gas of the reservoir chamber P is the high pressure chamber by itself only by opening the second solenoid valve element 194. 172 may be recovered.

In the above-described embodiment, the shock absorber 100 includes a pressure sensor 152 and an electronic control unit 150, based on the pressure information in the reservoir chamber P measured by the pressure sensor 152. It has been described that the control unit 150 controls the bidirectional valves including the first and second solenoid valve elements 192, 194 to open and close the bidirectional flow path between the reservoir chamber P and the high pressure chamber 172.

However, by configuring the first and second solenoid valve elements 192 and 194 constituting the bidirectional valves with the first and second check valves which open themselves by the change of gas pressure, the pressure sensor 152 and the electronic control The use of unit 150 may be omitted, which is also within the scope of the present invention. However, in order to supply gas and recover gas between the high pressure chamber and the reservoir chamber accurately and reliably, a configuration for electronically controlling the two-way valves is required, and when the electronic control unit and the pressure sensor are not used, gas flows. In addition to the pressure between the reservoir chamber and the high pressure chamber, the consideration of the gas pressure required to open the bidirectional check valve should be taken into account.

While the invention has been described above with reference to specific embodiments, various modifications, changes or modifications may be made in the art within the spirit and scope of the appended claims, and thus, the foregoing description and drawings It should be construed as illustrating the present invention rather than limiting the technical spirit of the present 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 thus in the compression stroke caused by the "lag" phenomenon. Attenuation force can be suppressed. In addition, the shock absorber according to the embodiment of the present invention can compensate for the gas loss in the reservoir chamber according to the increase in the service life of the shock absorber, thereby preventing the attenuation distortion caused by the gas loss in the reservoir chamber. Can be.

Claims (5)

The piston valve is connected to one end of the piston rod accommodated inside the inner cylinder and moved to the rebound stroke and the compression stroke, and the inner cylinder is partitioned into the rebound chamber and the compression chamber by the piston valve. A shock absorber having a reservoir chamber for supplying oil to a compression chamber in a rebound stroke and recovering oil in a compression stroke, A high pressure tank disposed below the outer cylinder and having a high pressure chamber communicating in both directions with the reservoir chamber by bidirectional valves selectively opened; A self-pumping unit that pumps the external gas by pumping the external gas by using the energy generated by the vertical movement of the piston rod; Shock absorber comprising a. The pumping rod of claim 1, wherein the self pumping unit is connected to the piston rod and moves together with the piston rod, and is provided to the atmospheric and high pressure chambers by first and second pumping passages, respectively. A pumping chamber provided inside the high pressure tank to allow retreat and forward, and the first pumping channel and the second pumping channel are opened in order by retreating and advancing the pumping rod, thereby allowing external gas to flow into the pumping chamber. And a first check valve and a second check valve operative to suck and supply the sucked gas to the high pressure chamber. The shock absorber according to claim 1 or 2, wherein the bidirectional valves are installed to open any one of the bidirectional flow paths according to the pressure change in the reservoir chamber according to the rebound stroke and the compression stroke of the piston rod. The body valve according to claim 1 or 2, wherein a body valve having a flow path connecting the compression chamber and the reservoir chamber is installed at a lower end of the inner cylinder, and the pumping rod is connected to the same axis as the piston rod so that the body A shock absorber, characterized in that penetrates through the valve and the lower end of the inner cylinder in a sealing manner. The shock absorber according to claim 1 or 2, wherein the high pressure chamber is air circulated in an upper portion of the reservoir chamber through a connecting pipe.

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