KR20130099435A - Damping force variable shock absorber - Google Patents

Abstract

PURPOSE: A damping force variable shock absorber is provided to improve riding quality when driving on a road of a good state or in a high speed by controlling a working fluid in a rebound chamber to move to a damping force variable valve assembly unit according to the frequency of vibration inputted in the shock absorber. CONSTITUTION: A damping force variable shock absorber comprises a base shell (12), an inner tube (14), a piston valve, a separator tube (16), and a frequency sensitive valve assembly unit. A damping force variable valve assembly is attached to the outside of the base shell. The inner tube is installed in the base shell, and a piston rod (24) is installed to be able to move in a longitudinal direction. The piston valve is connected to one end of a piston rod in order to divide the inner space of the inner tube with a rebound chamber (20) and a compression chamber. The separation tube is installed in order to divide the space between the base shell and the inner tube into a low pressure chamber (PL) and a high pressure chamber (PH) as a reservoir chamber (30). The frequency sensitive valve assembly unit includes a valve body (51) and a free piston (53). The valve body includes a penetration hole (51a) so that a working fluid in the rebound chamber flows in the high pressure chamber. The valve body is installed in between the rebound chamber and the high pressure chamber. The free piston opens or closes the penetration hole of the valve body according to the frequency inputted in the shock absorber.

Description

Damping force variable shock absorber {DAMPING FORCE VARIABLE SHOCK ABSORBER}

The present invention relates to a damping force variable shock absorber having a variable damping force valve assembly, and more particularly, to a damping force variable shock absorber having a frequency sensitive valve assembly to improve ride comfort when high frequency vibration is input.

Generally, a shock absorber is mounted on a moving means such as an automobile, and absorbs and buffers vibrations and shocks received from the road surface during traveling, thereby improving ride comfort.

Such a shock absorber includes a cylinder and a piston rod provided in the cylinder so as to be compressible and extensible, and the cylinder and the piston rod are respectively installed on a vehicle body, a wheel or an axle.

The shock absorber having a low damping force among the shock absorbers can absorb the vibration due to the unevenness of the road surface during traveling to improve ride comfort. On the other hand, the shock absorber having a high damping force has a characteristic in which the posture change of the vehicle body is suppressed and the steering stability is improved. Therefore, in the conventional vehicle, a shock absorber having a damping force characteristic different depending on the purpose of use of the vehicle is applied.

On the other hand, recently, a damping force variable valve capable of appropriately adjusting a damping force characteristic at one side of a shock absorber is installed, and a damping force variable shock which can appropriately adjust the damping force characteristic for improving ride comfort and steering stability according to the road surface and running condition, The absorber was developed.

1 is a cross-sectional view showing an example of a damping force variable shock absorber according to the prior art. The damping force variable shock absorber 10 according to the prior art includes a base shell 12 and an inner side of the base shell 12. Inner tube 14 is installed and the piston rod 24 is installed to be movable in the longitudinal direction. A rod guide 26 and a body valve 27 are provided at the upper and lower ends of the inner tube 14 and the base shell 12, respectively. A piston valve 25 is coupled to one end of the piston rod 24 in the inner tube 14 and the piston valve 25 connects the inner space of the inner tube 14 to the rebound chamber 20, Chamber 22 as shown in Fig. An upper cap 28 and a base cap 29 are provided on the upper and lower portions of the base shell 12, respectively.

Between the inner tube 14 and the base shell 12 is formed a reservoir chamber 30 for compensating for a volume change in the inner tube 14 due to the reciprocating movement of the piston rod 24. The flow of the working fluid between the reservoir chamber 30 and the compression chamber 22 is controlled by the body valve 27.

Further, a separator tube 16 is provided inside the base shell 12. The interior of the base shell 12 is divided into the high pressure chamber PH connected to the rebound chamber 20 by the separator tube 16, and the low pressure chamber PL as the reservoir chamber 30.

The high pressure chamber PH is connected to the rebound chamber 20 through the inner hole 14a of the inner tube 14. On the other hand, the low pressure chamber PL is a lower flow path 32 formed between the body portion of the body valve 27 and the base shell 12 (or the base cap 29), and a flow path formed in the body valve 27. It is connected to the compression chamber 22 through.

On the other hand, the shock absorber 10 according to the prior art includes a damping force variable valve assembly 40 mounted on one side of the base shell 12 to vary the damping force.

The damping force variable valve assembly 40 is formed with an oil flow path connected to the base shell 12 and the separator tube 16 and communicating with the high pressure chamber PH and the low pressure chamber PL, respectively. In addition, the damping force variable valve assembly 40 is provided with a spool 44 which is moved by the driving of the actuator 42, and the high pressure chamber PH and the low pressure chamber PL are moved by the movement of the spool 44. While communicating the internal flow path is variable, the damping force of the shock absorber 10 is variable.

However, in the damping force variable shock absorber according to the prior art, the working fluid in the rebound chamber 20 flows to the damping force variable valve assembly 40 without any resistance through the inner hole 14a and the high pressure chamber PH. There was also a problem that does not generate a damping force.

The present invention to solve the above problems, the driving fluid in the rebound chamber in accordance with the frequency of the vibration input to the shock absorber to control the flow of the damping force variable valve assembly by controlling the good road surface conditions and driving at high speed It is an object of the present invention to provide a damping force variable shock absorber having a frequency sensitive valve assembly for improvement.

According to an aspect of the present invention for achieving the above object, a damping force variable shock absorber for adjusting the damping force of the shock absorber, the base shell having a damping force variable valve assembly is attached to the outside; An inner tube installed inside the base shell and having a piston rod movable in a longitudinal direction; A piston valve coupled to one end of the piston rod to partition an inner space of the inner tube into a rebound chamber and a compression chamber; A separator tube installed to partition a space between the base shell and the inner tube into a low pressure chamber and a high pressure chamber; A frequency sensitive valve assembly installed to control the flow of the working fluid inside the rebound chamber toward the damping force variable valve assembly according to the frequency of the vibration input to the shock absorber; There is provided a damping force variable shock absorber comprising a.

The frequency sensitive valve assembly includes a valve body having a through hole formed therethrough so that the working fluid in the rebound chamber can flow into the high pressure chamber, and a valve body installed between the rebound chamber and the high pressure chamber, and a through hole of the valve body. It is preferable to include a free piston which is installed to open and close according to the frequency input to the shock absorber.

The free piston is preferably pressurized by pressurizing means so as to suppress the flow of the working fluid through the through hole when no external force is applied to the shock absorber.

In order to prevent the free piston from being separated from the valve body, a washer member for supporting the free piston is preferably fixed to the valve body.

The valve body is preferably formed integrally with a rod guide installed on the upper end of the base shell of the shock absorber.

According to the present invention as described above, the damping force variable shock absorber having a frequency-sensitive valve assembly to control the flow of the working fluid in the rebound chamber toward the variable damping force valve assembly in accordance with the frequency of the vibration input to the shock absorber. May be provided.

Accordingly, according to the shock absorber according to the present invention, it is possible to improve the riding comfort when high frequency vibration is input to the shock absorber, that is, when driving on a good road surface and driving at high speed.

1 is a cross-sectional view showing an example of a damping force variable shock absorber according to the prior art,
FIG. 2 is an enlarged cross-sectional view of an essential part of a damping force variable shock absorber having a frequency sensitive valve assembly according to the present invention, illustrating a state when high frequency vibration is input; and
3 is an enlarged cross-sectional view of an essential part of a damping force variable shock absorber having a frequency sensitive valve assembly according to the present invention, illustrating a state when low frequency vibration is input.

Hereinafter, a damping force variable shock absorber according to a preferred embodiment of the present invention will be described in detail with reference to the drawings.

2 and 3, the damping force variable shock absorber according to the present invention can control the flow of the working fluid in the rebound chamber toward the damping force variable valve assembly according to the frequency of the vibration input to the shock absorber. So that it has a frequency sensitive valve assembly. Hereinafter, the same components as those described with reference to FIG. 1 will be described with the same reference numerals for convenience.

The damping force variable shock absorber according to the present invention includes a base shell 12 having a damping force variable valve assembly 40 attached to the outside, similar to the damping force variable shock absorber according to the related art described with reference to FIG. The inner tube 14 is installed inside the base shell 12 and the piston rod 24 is movable in the longitudinal direction, and the inner space of the inner tube 14 includes the rebound chamber 20 and the compression chamber ( The low pressure chamber PL as the reservoir chamber 30 and the high pressure space are formed between the piston valve 25 coupled to one end of the piston rod 24 so as to be partitioned into 22 and the space between the base shell 12 and the inner tube 14. A separator tube 16 is installed to partition into the seal PH.

As shown in FIG. 1, the conventional rebound chamber 20 communicates with the damping force variable valve assembly 40 through the inner hole 14a and the high pressure chamber PH, but as shown in FIGS. 2 and 3. According to the present invention, the rebound chamber 20 is in communication with the damping force variable valve assembly 40 through the frequency sensitive valve assembly and the high pressure chamber PH.

Since the damping force variable shock absorber of the present invention is provided with a frequency sensitive valve assembly, when the oscillating displacement is small, that is, when the frequency input to the shock absorber is small and the displacement is small, the frequency sensitive valve assembly cannot be opened. It is possible to suppress the flow of the working fluid between the rebound chamber 20 and the high-pressure chamber (PH), thereby improving the riding comfort during high-speed driving and driving in a good road surface, such as when driving on the highway.

The frequency sensitive valve assembly has a through hole 51a formed therethrough so that the working fluid in the rebound chamber 20 can flow into the high pressure chamber PH, and is installed between the rebound chamber 20 and the high pressure chamber PH. And a free piston 53 provided to open and close the through-hole 51a of the valve body 51 according to the frequency input to the shock absorber.

The free piston 53 is pressurized by a spring 55 as a pressurizing means so as to suppress the flow of the working fluid through the through hole 51a when no external force is applied to the shock absorber.

In addition, a washer member 57 for supporting the free piston 53 is provided on the valve body 51 to prevent the free piston 53 pressurized by the spring 55 from being detached from the valve body 51. It is fixedly installed.

The valve body 51 of the frequency sensitive valve assembly may be integrally formed with the rod guide 26 installed on the top of the shock absorber base shell 12. 2 and 3 illustrate a valve body 51 integrally formed to extend from the bottom of the rod guide 26, the present invention is not limited to this and the valve body 51 is separate from the rod guide 26. Of course it can be formed. When the valve body 51 is formed separately from the rod guide 26, the upper end of the inner circumferential surface of the valve body 51 may be deformed so as to prevent the spring 55 from being separated from the valve body 51. Can be.

The valve body 51 preferably has a substantially cylindrical shape so that the free piston 53 can move in the vertical direction.

A band 54 of a material having a small coefficient of friction, such as Teflon, may be attached to at least one of the outer circumferential surface and the inner circumferential surface of the free piston 53 to reduce frictional force during vertical movement. 2 and 3 illustrate that the band 54 is attached only to the outer circumferential surface of the free piston 53, but the band may be attached only to the inner circumferential surface of the free piston 53 or may be modified to attach the band to both the outer and inner circumferential surfaces thereof. have.

The spring 55 may be seated on a seating surface formed on the lower surface of the rod guide 26 and the upper surface of the free piston 53, respectively. A seating groove may be formed in the seating surface to prevent left and right swinging of the spring.

Hereinafter, the operation of the frequency sensitive valve assembly installed in the damping force variable shock absorber of the present invention will be described with reference to FIGS. 2 and 3.

2 shows a state of the frequency sensitive valve assembly when high frequency vibration is input to the shock absorber.

In the case of high-speed driving on a highway with good road conditions, high frequency vibration, that is, high frequency low amplitude vibration, may be input to the shock absorber. Since the free piston 53 included in the frequency-sensitive valve assembly of the present invention is supported by the spring 55, the working fluid in the rebound chamber 20 is applied until an external force greater than the elastic force of the spring 55 is input. It cannot flow into the high pressure chamber (PH).

At this time, the damping force generated in the frequency sensitive valve assembly is governed by the inherent spring constant of the spring 55, a relatively soft damping force is generated.

Figure 3 shows the state of the frequency sensitive valve assembly when low frequency vibration is input to the shock absorber.

When driving on a road with poor road conditions or when crossing a mound, low frequency vibration, that is, low frequency high amplitude vibration, may be input to the shock absorber. Since the free piston 53 included in the frequency sensitive valve assembly of the present invention is supported by the spring 55, when the low frequency high amplitude vibration greater than the elastic force of the spring 55 is input, the free piston 53 is spring ( The through hole 51a can be opened by moving while compressing 55.

When the through hole 51a is opened, the working fluid in the rebound chamber 20 may flow into the high pressure chamber PH. When the through hole 51a is opened, the spring 55 no longer affects the damping force.

At this time, the damping force generated in the frequency sensitive valve assembly is controlled by the piston valve 25, the body valve 27 and the damping force variable valve assembly 40 installed in the damping force variable shock absorber, and the relatively hard damping force. Is generated.

Although the present invention has been described above with reference to the illustrated drawings, the present invention is not limited to the embodiments and drawings described above, and those skilled in the art to which the present invention pertains within the scope of the claims. Various modifications and variations can be made by, of course.

10 damping force variable shock absorber 12 base shell
14: inner tube 16: separator tube
20: rebound chamber 22: compression chamber
24: piston rod 25: piston valve
26: rod guide 27: body valve
30 reservoir chamber 40 damping force variable valve assembly
51 valve body 51a through hole
53: free piston 54: band
55: spring 57: washer member
PL: low pressure chamber PH: high pressure chamber

Claims (5)

A damping force variable shock absorber that adjusts the damping force of the shock absorber.
A base shell to which the damping force variable valve assembly is attached to the outside;
An inner tube installed inside the base shell and having a piston rod movable in a longitudinal direction;
A piston valve coupled to one end of the piston rod to partition an inner space of the inner tube into a rebound chamber and a compression chamber;
A separator tube installed to partition a space between the base shell and the inner tube into a low pressure chamber and a high pressure chamber;
A frequency sensitive valve assembly installed to control the flow of the working fluid inside the rebound chamber toward the damping force variable valve assembly according to the frequency of the vibration input to the shock absorber;
Damping force variable shock absorber comprising a. The method according to claim 1,
The frequency sensitive valve assembly includes a valve body having a through hole formed therethrough so that the working fluid in the rebound chamber can flow into the high pressure chamber, and a valve body installed between the rebound chamber and the high pressure chamber, and a through hole of the valve body. A damping force variable shock absorber comprising a free piston installed to open and close according to the frequency input to the shock absorber. The method according to claim 2,
The free piston is variable damping force absorber, characterized in that the pressurizing means is pressed by the pressing means to suppress the flow of the working fluid through the through hole when no external force is applied to the shock absorber. The method according to claim 2,
The damper force variable shock absorber, characterized in that the washer member for supporting the free piston is fixed to the valve body to prevent the free piston from being separated from the valve body. The method according to claim 2,
The valve body is a damping force variable shock absorber, characterized in that formed integrally with the rod guide is installed on the top of the base shell of the shock absorber.

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