KR20150137619A - Shock absorber with a frequency unit - Google Patents

Abstract

The present invention relates to a frequency-sensitized shock absorber having a cylinder filled with working fluid, and a piston rod having an end placed inside the cylinder and having the other end extending out of the cylinder. The shock absorber comprises: a main piston valve assembly (30) installed on one end of the piston rod and operating while bisecting the inside of the cylinder into a tension chamber (11) and a compression chamber (12) to generate a damping force which changes depending on a moving speed; and an auxiliary piston valve assembly (100) moving together with the main piston valve assembly and generating a damping force which changes depending on a frequency. The auxiliary piston valve assembly includes: a spool unit (120) for opening and closing a communicating flow path, which allows the tension chamber and the compression chamber to communicate with each other while moving vertically in the housing (110); and a lower washer (150) mounted on an opening at the lower end of the housing. The spool unit is supported by being interposed between an upper step part (130), which has been formed at the upper part of the inside of the housing, and a lower step part (140), which has been formed on the lower washer.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a frequency-responsive shock absorber,

The present invention relates to a frequency-responsive shock absorber, and more particularly, to a shock-absorbing shock absorber capable of simultaneously controlling a damping force with respect to a low amplitude and a high amplitude during compression and tensioning of a piston valve, To a frequency-responsive shock absorber having a structure that minimizes rise and is advantageous for basic design.

Generally, a vehicle is equipped with a shock absorber for improving ride comfort by absorbing shocks or vibrations that the axle receives from the road surface when the vehicle is traveling, and a shock absorber is used as one of such shock absorbers.

The shock absorber operates according to the vibration of the vehicle according to the road surface condition. At this time, depending on the operating speed of the shock absorber, that is, the operating speed is fast or slow, the damping force generated in the shock absorber changes.

The riding comfort and driving stability of the vehicle can be controlled by adjusting the damping force characteristics generated by the shock absorber. Therefore, when designing a vehicle, it is very important to adjust the damping force characteristics of the shock absorber.

Conventional piston valves are designed to have constant damping characteristics at high speed, medium speed, and low speed by using a single flow path. Therefore, if the low speed damping force is lowered to improve ride comfort, the second speed damping force may be affected. In addition, the conventional shock absorber has a structure in which the damping force changes in accordance with the speed change of the piston regardless of the frequency or the stroke. Since the damping force changed only in accordance with the speed change of the piston generates the same damping force in various road surface conditions, it is difficult to simultaneously satisfy the ride comfort and the adjustment stability.

Accordingly, it is necessary to continuously research and develop a valve structure of a shock absorber that can vary the damping force according to various road surface conditions, that is, the excitation frequency and stroke, and can satisfy the ride comfort and the adjustment stability of the vehicle at the same time.

In addition, it is possible to realize the performance desired by the designer in the structure of opening and closing the flow path for varying the damping force, but also the structure is simple and the number of parts can be reduced. Thus, the manufacturing cost can be reduced, and the shock absorber valve Structure is required.

Japan Public Utility New Public Affairs Office Open 5-36149

In order to solve such conventional problems, an auxiliary valve for generating a damping force varying according to frequency is installed together with a piston valve to satisfy the riding comfort of the vehicle and the adjustment stability, And to provide a frequency-sensitive shock absorber having a structure advantageous to design.

According to an aspect of the present invention, there is provided a shock absorber including a cylinder filled with a working fluid, a piston rod having one end located inside the cylinder and the other end extending to the outside of the cylinder, The main piston valve assembly being operated in a state where the inside of the cylinder is divided into a tension chamber and a compression chamber to generate a damping force varying with a moving speed; An auxiliary piston valve assembly moving with said main piston valve assembly and generating a damping force varying with frequency; Wherein the auxiliary piston valve assembly includes a spool unit for opening and closing a communication passage communicating between the tension chamber and the compression chamber while moving up and down in the housing; A lower washer mounted on a lower end opening of the housing; Wherein the spool unit is interposed between and supported by an upper stepped portion formed on an inner upper portion of the housing and a lower stepped portion formed on the lower washer.

The spool unit may include a spool moving up and down by an external force, and upper and lower discs sandwiching the spool.

The upper stepped portion may be formed integrally with the upper portion of the inner side of the housing so as to abut the outer circumferential portion of the upper disk, and the lower stepped portion may be integrally formed on the upper portion of the lower washer to abut the outer circumferential portion of the lower disk.

The spool unit includes a spacer interposed between the upper and lower discs such that the upper and lower discs are parallel to each other, and the spacer may be made of a material having elasticity.

The communication passage includes a connecting passage in the piston rod, an upper space in the housing, a through hole formed in the upper and lower disks, a lower space in the housing, and a hole formed in the lower washer .

According to the present invention as described above, it is possible to provide a frequency-sensitive shock absorber including an auxiliary valve for generating a damping force varying in frequency.

Accordingly, the shock absorber manufactured by the manufacturing method according to the present invention can satisfy the riding comfort and stability stability of the vehicle at the same time, minimizes cost increase, and has a structure favorable for basic design.

1 is a sectional view showing a valve structure of a frequency-responsive shock absorber according to the present invention,
FIG. 2 is a sectional view of a main part for explaining a valve structure of a frequency-responsive shock absorber according to the present invention in low-
3 is a cross-sectional view of a main part for explaining a valve structure of a frequency-sensitive shock absorber according to the present invention when a low frequency is pulled, and
4 is a cross-sectional view illustrating a valve structure of a frequency-responsive shock absorber according to a modification of the present invention.

Hereinafter, a valve structure of a frequency-sensitive shock absorber according to a preferred embodiment of the present invention will be described in detail with reference to the drawings.

1, a frequency-responsive shock absorber according to the present invention includes a substantially cylindrical cylinder 10, which is filled with a working fluid such as oil, and a cylindrical body 10 having one end located inside the cylinder and the other end located outside the cylinder And a piston rod 20 extending therefrom.

The valve structure of the shock absorber according to the present invention is provided at one end of the piston rod 20 and operates in a state where the inside of the cylinder is divided into the tension chamber 11 and the compression chamber 12, And a subsidiary valve assembly 100 that moves with the main piston valve assembly 30 and generates a damping force that varies with frequency.

The main piston valve assembly 30 and the auxiliary valve assembly 100 are installed at the ends of the piston rod 20 in series. The other end side of the piston rod 20 is slidable with respect to the rod guide and the oil seal and extends axially through the cylinder to the outside of the cylinder.

In the main piston valve assembly 30, at least one main compression passage 32 through which the working fluid passes during compression of the shock absorber, and at least one main tension passage 33 through which the working fluid passes when the shock absorber is tensioned A main compression valve portion 35 disposed at an upper portion of the main piston body 31 to generate a damping force against the pressure of the working fluid that has passed through the main compression passage 32, And a main tension valve portion 37 disposed at a lower portion of the piston main body 31 to generate a damping force against the pressure of the working fluid passing through the main tension passage 33.

The outer peripheral surface of the main piston body 31 may be provided with a band 39 made of Teflon for adhesion with the inner circumferential surface of the cylinder 10 and prevention of abrasion.

The main piston valve assembly 30 is not limited to only the configuration shown in FIG. 1, and the present invention is not limited by the configuration of the main piston valve assembly 30. FIG. The configuration of the main piston valve assembly 30 shown in Fig. 1 is only an example.

The auxiliary valve assembly 100 according to the present embodiment includes a hollow housing 110 mounted at the lower end of the piston rod 20 so as to be disposed below the main piston valve assembly 30 and hollow inside, And a lower washer 150 mounted to close the lower end opening of the housing 110. The spool unit 120 includes a spool unit 120 for opening /

The inner space of the housing 110 can be divided into an upper space 111 and a lower space 112 by the spool unit 120. [ An upper space 111 which is an upper space of the spool unit 120 in the inner space of the housing 110 can communicate with the tension chamber 11 through a connection passage 21 formed inside the piston rod 20 . The lower space 112 which is the lower space of the spool unit 120 in the inner space of the housing 110 can communicate with the compression chamber 12 through the hole 151 formed in the lower washer 150.

The connecting passage 21 formed inside the piston rod 20 is illustrated as being formed by perforating the longitudinal passage 21a and the transverse passage 21b so as to intersect each other as shown in FIG. May have a different structure than that shown in Figure 1 if it can connect the tension chamber 11 with the inner space of the housing 110 (and hence the compression chamber 12)

An upper stepped portion 130 for supporting the spool unit 120 from above is formed in an inner upper portion of the housing 110 in a substantially annular shape. A lower step portion 140 for supporting the spool unit 120 from below is formed in an upper portion of the lower washer 150 so as to protrude in a substantially annular shape. The upper stepped portion 130 of the housing 110 and the lower stepped portion 140 of the lower washer 150 can move the spool unit 120 upward and downward when the lower washer 150 is coupled to the housing 110. [ As shown in Fig.

The upper stepped portion 130 is formed integrally with the housing 110 and the lower stepped portion 140 is formed integrally with the upper washer 150.

The spool unit 120 includes a spool 121 that moves up and down in accordance with a frequency (amplitude) in an internal space of the housing 110 and a spool 121 which is disposed above and below the spool 121, And upper and lower discs 122 and 123 supporting the upper and lower discs 122 and 123 and a lower disc 122 and 123 interposed between the upper and lower discs 122 and 123 such that the upper and lower discs 122 and 123 have approximately the same thickness as the spool 121, And includes a spacer 124.

The spool 121 has a disc shape in which the thickness of the center portion is thicker than the thickness of the outer circumferential portion. The upper and lower protrusions 121a and 121b are formed in the central portion of the spool 121 and the upper and lower protrusions 121a and 121b are formed in the central hole formed in the center of the upper and lower discs 122 and 123, And can be abutted against each other.

The upper and lower disks 122 and 123 are provided with through holes 122a and 123a so that the working fluid can flow between the upper space 111 and the lower space 112 without an external force being applied to the spool 121. [ .

The spacer 124 may be made of an O-ring having a circular cross section, and is made of a material having elasticity such as rubber.

The upper stepped portion 130 is formed on the inner upper portion of the housing 110 so as to abut the outer circumferential portion of the upper disk 122 of the spool unit 120 in order to maintain the spool 121 in the neutral position when no external force is applied And the lower stepped portion 140 is formed on the upper portion of the lower washer 150 so as to abut the outer circumferential portion of the lower disk 123 of the spool unit 120.

The spool 121 moves upward and the upper surface of the spool 121, that is, the upper surface of the upper convex portion 121a is connected to the connecting passage (not shown) formed in the piston rod 20 21, that is, when the opening of the vertical passage 21a is closed, the flow of the working fluid is blocked. Alternatively, when the spool 121 moves downward according to the input frequency and the lower surface of the spool 121, that is, the lower surface of the lower convex portion 121b blocks the hole 151 formed in the lower washer 150 The flow of the working fluid is cut off.

In order to more reliably block the flow of the working fluid at this time, the sealing layer may be formed of a material having elasticity such as rubber on the upper portion of the lower washer 150, though not shown. Although not shown, the sealing layer can be formed of a material having elasticity such as rubber on the lower end surface of the piston rod 20 in which the opening of the connecting passage 21 is formed.

Although not shown, by covering the outer surface of the spool 120, at least the upper surface and the lower surface of the spool 120 with an elastic material such as rubber, The flow of the working fluid can be more reliably blocked when the hole 151 or the hole 151 of the lower washer 150 is closed.

The flow of the working fluid can be reliably blocked when the metal spool 120 is brought into contact with the material having elasticity in comparison with the case where the metal spool 120 is also configured to block the hole formed in the metal lower washer or the piston rod, .

1, the upper and lower disks 122 and 123, which hold the spool 121 therebetween, are each formed of a single disk. However, if the working fluid can flow through the disk, The upper and lower discs may be formed in a structure in which two or more discs are superimposed on each other. In the case where a plurality of disks are stacked, a through hole may be formed in each disk, or a slit or an opening of a different shape may be formed, and a passage of a certain area may be formed when superimposed.

The lower washer 150 that closes the lower end opening of the housing 110 is fixed by screwing the housing 110 to the housing 110 or by inserting the lower washer and deforming the housing, And can be fixed by fastening the fastening member to the housing.

4, substantially cylindrical protrusions 121c and 121d may protrude from the upper and lower protrusions 121a and 121b of the spool 121, respectively, as shown in FIG. 4 . The projection 121c protruding from the upper convex portion 121a loosely fits within the vertical passage 21a formed in the piston rod 20 and the projection 121d protruding from the lower convex portion 121b is engaged with the lower washer 150. [ And is loosely fitted in the hole 151 of the housing 151.

The protrusions 121c and 121d projecting in a substantially cylindrical shape are loosely inserted into the vertical passage 21a of the piston rod 20 and the hole 151 of the lower washer 150, The moving direction of the spool 121 can be guided so as to move substantially linearly without being distorted when the spool 121 moves up and down.

Hereinafter, the operation of the valve structure according to the preferred embodiment of the present invention will be described with reference to Figs.

1 shows the position of the spool unit 120 at high frequency (i.e., low amplitude) and FIGS. 2 and 3 show the position of the spool unit 120 at low frequency (i.e., high amplitude). More specifically, FIG. 2 shows the position of the spool unit 120 during low-frequency compression, and FIG. 3 shows the position of the spool unit 120 during low-frequency pulling.

The spool unit 120 can move up and down while deforming the upper and lower disks 122 and 123 when an external force such as inertia and working fluid pressure is applied. That is, if the magnitude of the external force acting on the spool unit 120 is large enough to deform the upper and lower disks 122 and 123, the spool 121 moves upward or downward.

1 shows a state in which the amplitude of the movement of the piston rod of the shock absorber is small and the number of vibrations is high so that the magnitude of the external force acting on the spool 121 is not large enough to deform the upper and lower disks 122 and 123 have. The working fluid can flow through the through holes 122a and 123a formed in the upper and lower disks 122 and 123 without the spool 121 moving.

The spool 121 moves so that the upper surface or the lower surface of the spool 121 closes the opening of the connecting passage 21 formed in the piston rod 20 or the lower washer 150 The through holes 122a and 123a formed in the upper and lower disks 122 and 123 are in an open state even when the magnitude of the external force acting on the spool 121 is not large enough to block the hole 151 in the upper and lower disks 122 and 123 .

At this time, the auxiliary valve assembly 100 generates the damping force by the flow of the working fluid generated by the movement of the spool 121.

At this time, the flow path between the compression chamber 12 and the tension chamber 11 (i.e., the connecting passage 21 in the piston rod 20, the upper space 111 in the housing 110, the upper and lower disks 122, The through holes 122a and 123a of the upper and lower washers 123 and 123 and the lower space 112 in the housing 110 and the holes 151 in the lower washer 150 are open.

2 and 3, the amplitude of the movement of the piston rod of the shock absorber is large and the number of vibrations is small so that the magnitude of the external force acting on the spool 121 causes the spool to move while the upper and lower disks 122 and 123 are deformed, 121 are so large as to block the opening of the connecting passage 21 formed in the piston rod 20 or to block the hole 151 of the lower washer 150. [

At this time, the upper surface of the spool 121 closes the opening of the connection passage 21 formed in the piston rod 20, or the lower surface of the spool 121 penetrates through the hole 151 of the lower washer 150 The flow of the working fluid through the holes 122a and 123a is blocked and the flow path between the compression chamber 12 and the tension chamber 11 is closed.

In this manner, the damping force can be obtained by the main piston valve assembly 30 since the flow of the working fluid through the auxiliary valve assembly 100 is closed at the low frequency and high vacuum.

As described above, the frequency-sensitive shock absorber according to the present invention has been described with reference to the drawings. However, the present invention is not limited to the above-described embodiments and drawings, It is to be understood that various changes and modifications may be made by those skilled in the art.

10: cylinder 11: tension chamber
12: Compression chamber 20: Piston rod
21: connecting passage 30: main piston valve assembly
31: main piston body 32: main compression passage
33: main tension passage 35: main compression valve section
37: main tension valve part 39: band
100: auxiliary valve assembly 110: housing
111: upper space 112: lower space
120: spool unit 121: spool
121a: upper convex portion 121b: lower convex portion
122: upper disk 122a, 123a: through hole
123: Lower disk 124: Spacer
130: upper step 140: lower step
150: lower washer 151: hole

Claims (5)

A shock absorber having a cylinder (10) filled with a working fluid, a piston rod (20) having one end located inside the cylinder and the other end extending outside the cylinder,
A main piston valve assembly 30 installed at one end of the piston rod and operated in a state where the inside of the cylinder is divided into a tension chamber 11 and a compression chamber 12 to generate a damping force varying with a moving speed; An auxiliary piston valve assembly (100) that moves with the main piston valve assembly and generates a damping force that varies with frequency; / RTI >
The auxiliary piston valve assembly includes a spool unit (120) for opening and closing a communication passage communicating between the tension chamber and the compression chamber while vertically moving within the housing (110); A lower washer 150 mounted to the lower end opening of the housing; / RTI >
Wherein the spool unit is interposed and supported between an upper stepped portion formed on an inner upper portion of the housing and a lower stepped portion formed on the lower washer. The method according to claim 1,
The spool unit includes a spool (121) moving up and down by an external force, and upper and lower discs (122, 123) sandwiching the spool. The method of claim 2,
The upper stepped portion 130 is integrally formed on the inner upper portion of the housing 110 so as to abut the outer circumferential portion of the upper disk 122. The lower stepped portion 140 is formed integrally with the outer circumferential portion of the lower disk 123, Is formed integrally with the upper portion of the lower washer (150) so as to abut the portion of the lower washer (150). The method of claim 2,
The spool unit 120 includes a spacer 124 interposed between the upper and lower disks 122 and 123 such that the upper and lower disks 122 and 123 are parallel to each other, A frequency-sensitive shock absorber made of a material. The method according to claim 1,
The communication passage includes a connection passage 21 in the piston rod 20, an upper space 111 in the housing 110, through holes 122a and 122b formed in the upper and lower disks 122 and 123, 123a), a lower space (112) in the housing (110), and a hole (151) formed in the lower washer (150).

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