JPS61109933A - Hydraulic damper - Google Patents

Abstract

PURPOSE:To obtain stable action what is called hi-cut action, by a method wherein bending characteristics of the edge of the outer circumference of an annular relief valve is changed by applying pressing force from the upper part corresponding to frequency to the edge of the relief valve. CONSTITUTION:A relief valve 50 whose edges of the inner circumference and outer circumference are supported respectively by a supporting point 52 and annular seat 53 is arranged within a piston nut 4. The relief valve 50 is made to form a flow path and generate attenuation force on an extension side due to a matter that the edge of the external circumference of the relief valve 50 is bent. A push valve 55 is abutted against the other side of the supporting point 52 of the edge of the inner circumference of the relief valve 50. A spool 57 is arranged on a coaxial line to the push valve 55 through spring 56 and the spool 57 is faced on a pressure chamber 58 communicating with an oil chamber of a cylinder through an orifice 43. Inner pressure of the pressure chamber 58 acts upon the edge of the inner circumference of the relief valve 50 as pressing force of the same through the spool 57, spring 56 and push valve 55.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hydraulic shock absorber, and more particularly to a hydraulic shock absorber capable of performing a so-called high-cut action that reduces damping force in a region above a given frequency.

[Conventional technology]

There have been various proposals in the past for performing a so-called high-cut action that reduces the damping force in a region above a given frequency.

According to these proposals, it is theoretically disclosed that a high-cut effect is exhibited in a region of a predetermined frequency or higher.

[Problem that the invention seeks to solve]

However, when using the above-mentioned conventional proposals, there are disadvantages in that the desired stable high-cutting action cannot be obtained, the number of processing steps increases to obtain the desired configuration, and the number of parts increases.

That is, the reality is that there has not yet been a proposal for a hydraulic shock absorber that can provide a stable damping force reduction effect in a frequency range above a given frequency and is also economically advantageous.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a hydraulic shock absorber having a new configuration that can perform a stable so-called high-cut action in a frequency range above a given frequency range and is economically advantageous.

[Means for solving problems]

In order to solve the above-mentioned problems, the structure of the present invention is such that the hydraulic pressure is formed so that the damping force generated by the damping force generating section C when the piston section slides can be reduced in an arbitrary frequency range or above. In the shock absorber, the damping force generating part has an annular leaf valve, and is capable of generating a damping force of a predetermined magnitude by the outer peripheral end of the leaf valve,
and the amount of deflection of the outer circumferential end is made variable by a pressing force applied to the inner circumferential end of the leaf valve, and the pressing force is formed above the inner circumferential end of the leaf valve, and the orifice is The internal pressure of the pressure chamber is obtained by the internal pressure of the pressure chamber that communicates with the oil chamber in the cylinder through the spring, and the internal pressure of the pressure chamber is applied to the spool that is in contact with the upper surface of the inner peripheral end of the leaf valve via a spring that expands and contracts as the bushing valve slides. It is characterized by being formed so that it can be transmitted.

〔Example〕

The present invention will be explained below based on the illustrated embodiments.

As shown in FIG. 1, the hydraulic shock absorber according to the present invention has a piston part 3 at the tip of a piston rod 2 that is slidably inserted into a cylinder 1, and the piston part 3 is connected to the piston rod 2. A damping force generating portion 5 is provided within a piston nut 4 fixed to the tip. In this embodiment, the hydraulic shock absorber is formed into a double cylinder type, and an outer tube 10 is disposed outside the cylinder 1.

The upper end of the cylinder 1, that is, the outer tube 1
A bearing member 11 is disposed inside the upper end of the bearing member 1, and the piston rod 2 is slidably inserted into the shaft core through-hole of the bearing member 11. A packing case 13 fixed with a ring nut 12 is disposed above the bearing member 11, and the packing case 13 has a packing 15 held by a packing plate 14.

Further, a packing spring 16 is interposed between the packing plate 14 and the lower bearing member 11,
The upper edge of the outer peripheral end of the bearing member 11 and the packing case 13
An O-link F is interposed between the lower surface of the outer periphery and the lower surface of the outer periphery.

The inside of the cylinder 1 is divided into a rod-side oil chamber A and a piston-side oil chamber B by the piston portion 3.

Although not shown, a base valve part is formed inside the lower end of the cylinder 1, and is formed between the piston side oil chamber B, the cylinder 1, and the outer tube 10 via the base valve part. It is in communication with the reservoir chamber C where the storage is carried out. Note that the upper part of the reservoir chamber C is gas 'J'.
It is said to be D. Further, leaked oil accumulated on the upper surface of the bearing member 11 flows into the gas reservoir chamber C through a port 11α formed in the bearing member 11.

Further, although the lower end of the cylinder 1 is not shown in the figure, it has an eye for attachment, so that it can be connected to the axle side of a vehicle.

Although not shown, the piston rod 2 is formed such that its upper end can be connected to a vehicle body plate or the like of a vehicle. An oil passage 2o is formed in the interior from the lower end to the vicinity of the lower end of the piston rod 2, and is bored through the axial core of the piston rod 2, and at the lower end of the oil passage 20. is opened on the piston-side oil chamber B side, that is, inside the piston nut 4, and is connected to the oil passage 20.
The upper end of the rod side oil chamber A is communicated with the rod side oil chamber A through a communication hole 21.

Therefore, the oil pressure in the rod side oil chamber A is
1 and the oil passage 20, and extends into the piston nut 4.

The piston part 3 has a piston body 3o that is disposed on the spigot part 22 of the piston rod 2 and fixed by the piston nut 4. It is divided into a chamber A and a piston side oil chamber B. and,
An oil passage 31 is bored in the piston body 30,
The rod side oil chamber A and the piston side oil chamber B are allowed to communicate with each other. Furthermore, a check valve 32 made of a leaf valve is disposed on the upper end opening side of the oil passage 31 so as to close the opening.

The check valve 32 is urged downward by a spring 34 whose upper end is engaged with a stopper 33 which is engaged with the stepped portion 23 of the piston rod 2. Further, the stopper 33 is formed with a notch 33α through which oil can pass, and a piston ring 35 is interposed on the outer periphery of the piston body 30.

Therefore, the oil passage 31 in the piston part 3 allows the oil in the piston-side oil chamber B to flow into the rod-side oil chamber A only when the piston part 3 is moving downward in the cylinder 1. This is a pressure side oil passage that allows for.

In this embodiment, the damping force generating section 5 in the piston nut 4 is an expansion side damping force generating section, and a block 40 disposed in the piston nut 4
0 has an annular leaf valve 50 disposed adjacent to the lower end opening of the oil passage 41, and the annular leaf valve 50 includes:
Disc 51 screwed inside the lower end of piston nut 4
The support point 52 of is supported so as to be in contact with the lower surface.

Note that the support point 52 is connected to the upper annular leaf valve 5.
On the outer peripheral side upper end surface of the disk 51 having the support point 52, there is an annular portion 53 having the same wall thickness as the leaf valve 50. is installed. The ring portion 53 may be omitted and a raised portion having the same thickness as the leaf valve 50 may be formed in advance at the upper end of the outer peripheral side of the disk 51, but as in this embodiment, Providing the ring portion 53 has the advantage of making it easier to finish the upper surface of the disk 51 and making it easier to manage machining accuracy.

The outer peripheral end of the annular leaf valve 50 is a free end, and the oil in the piston nut 4, that is, in the rod side oil chamber A, passes through the oil passage 41 of the upper block 40. The outer peripheral end of the leaf valve 5o is bent to allow the oil to flow into the piston side oil chamber B through the oil passage 54 of the disc 51, and a desired rebound damping force is generated when the outer peripheral end of the leaf valve 5o is bent. It looks like this. The expansion-side damping force is made variable by applying a pressing force from above to the inner peripheral end of the annular leaf valve 50.

That is, the bush valve 55 is in contact with the upper surface of the inner peripheral end of the annular leaf valve 5o, and the lower end of the spring 56 is in contact with the upper surface of the bush valve 55.
Moreover, a spool 57 is brought into contact with the upper end of the spring 56. The bushing valve 55, spring 56 and spool 57 are housed in a block 40 within the piston nut 4, and a pressure chamber 58 is formed in the upper surface of the spool 57. The pressure chamber 58 is defined and layered by a disc-shaped check valve 42 arranged so as to close the central opening of the upper end of the block 4o in the piston nut 4.

An orifice 43 is formed in the center of the check valve 42, and the pressure chamber 58 and the inside of the rod-side oil chamber A communicate with each other through the orifice 43.

Therefore, when the inside of the rod side oil chamber A becomes a high pressure side, the reduced pressure acts on the inside of the pressure chamber 58 through the orifice 43, that is, the pressure chamber 5
8 acts as a pressure reducing chamber, and this reduced hydraulic pressure acts on the bushing valve 55 via the spool 57 and spring 56, and the annular leaf valve 5
The inner peripheral end of 0 is pressed downward. Then, due to the pressing force from above on the inner peripheral end, the outer peripheral end of the leaf valve 50 is urged to be pressed against the lower surface of the upper block 40, that is, the outer peripheral end of the leaf valve 50 The deflection characteristics of the material will be changed. Furthermore, by changing the pressure in the pressure chamber 58, the outer peripheral end deflection characteristics of the leaf valve 50 are changed.

Note that the disk-shaped check valve 42 is pushed downward by a spring 44 whose upper end is locked to the piston nut 4.
That is, it is energized toward the top surface of the block 40.

Therefore, when the pressure inside the rod side oil chamber A becomes low, the check valve 42 is opened and the pressure inside the pressure chamber 58 is eliminated without any pressure accumulation.

The operation of the hydraulic shock absorber according to the present invention formed as described above will be briefly explained.

During the extension stroke when the piston part 3 moves up inside the cylinder 1,
The inside of the rod side oil chamber A becomes a high pressure side, and the oil in the rod side oil chamber A flows into the piston nut 4 via the communication hole 21 and the oil passage 20. A part of the oil that has flowed into the piston nut 4 flows into the pressure chamber 58 through the orifice 43 of the check valve 42, and the other oil flows through the oil passage 41 of the block 40 into the leaf valve. The outer peripheral end of 40 is bent, and the oil flows into the piston side oil chamber B.

At this time, when the vibration frequency in the oil chamber A on the rond side exceeds a certain range, high pressure is no longer generated in the pressure chamber 58, that is, the inner peripheral end of the lift valve 50 is pressed, and the outer peripheral end thereof is pressed. When the leaf valve 50 is pressed against the block 40, the pressing force that would generate a high damping force is no longer generated, and as a result, the leaf valve 50 is returned to its initial deflection characteristics,
This results in a so-called high-cut phenomenon in which the generation of high damping force is stopped.

That is, as shown in Figure 2, a bushing valve 55 is connected to the leaf valve 50 between the oil pressure P above the check valve 42 on the high pressure side and the oil P2 in the pressure chamber 58 below the check valve 42. The following equation (1) holds true in relation to the force F/ that presses the inner peripheral end.

Here, t: Time Pl; High pressure side 1 pressure Pko, -Next lag pressure chamber side pressure K Spring constant A of second spring 56 Pressure receiving area R of spool 57/Fluid resistance of oil flowing through niorifice 43 R2= This is the fluid resistance of oil flowing around the outer circumference of the spool 57.

Therefore, for example, if Pl changes in a sinusoidal half wave as shown in equation (2) below, P2 changes as shown in Figure 3 by solving equation (1).

p/=p1oJ' Z rL2πft (0-=t≦7/
2πf) ---(2) where Plo: constant.

Therefore, as can be seen from FIG. 3, as the frequency f of Pl increases, P- becomes smaller than Pl in most of the time domain. In other words, the damping force can be reduced. The rate of decrease and the frequency at which the decrease starts can be arbitrarily selected by appropriately selecting the spring constant of the spool 57, the pressure receiving area A of the spool 57, the fluid resistance R of the oil, and R2. This means that desired characteristics can be obtained.

FIG. 4 shows a hydraulic shock absorber according to another embodiment of the present invention, and the operation in this embodiment is the same as that on the actual flow side in FIG. 1.

However, there are some modifications in the configuration, and the modified portions will be explained below.

The piston body 30 of the piston portion 3 is provided with an oil passage 36 on the expansion side in addition to an oil passage 31 on the compression side. The check valve 32 has a notch 32α at a portion facing the upper end opening of the oil passage 36.

The lower end opening of the oil passage 36 is opposed to the upper end opening of an oil passage 45 bored in the piston nut 4.

Furthermore, the lower end of the oil passage 45 opens inside the piston nut 4.

That is, the oil passage 36 is replaced with the communication hole 21 and the oil passage 20 in the piston rod 2 in the embodiment shown in FIG.
and 45 are bored in the piston body 30 and the piston nut 4, respectively.

In this embodiment, the disk 51 is fixed to the lower end of the piston nut 4 by caulking.

FIG. 5 shows an embodiment in which the base valve part 6 is used as the expansion side valve part in the piston part 3 part of the fan 1 diagram.

That is, the outer tube 1 is attached to the lower end of the cylinder 1.
A base valve case 60 is provided between the base valve case 60 and the cap member 18 that seals the lower end of the base valve case 60, and a compression side damping force generating section is provided within the base valve case 60, and a check valve section 7 is provided at the upper end of the base valve case 60. It is something that Note that an eye 19 is fixed to the cap member 18.

Inside the base valve case 60, a block 61, a leaf valve 62, a disk 63, an annular portion 64, a check valve 65, and a spring 66 are arranged.
Inside the flock 61 is a bushing valve 67 and a spring 6.
8. A spool 69 is provided. The configuration inside the gas valve 60 and the configuration inside the block 61 are as follows:
The structure inside the piston nut 4 and the structure inside the block 40 in FIG. The oil in the side oil chamber B is formed so as to flow into the base valve case 60, and when the oil flows in, a desired compression side damping force is generated and a so-called high cut effect is exerted in a region above a given frequency. It is something.

Note that a cutout 60α is formed at the lower end of the base valve case 60, and communication between the inside of the base valve case 60 and the reservoir chamber C is made possible through the cutout 60a. Further, a bushing valve 67, a spring 68, and a spool 69 are housed in the block 61.

In addition, the base valve case 60 has a communication hole 72 in the thick part at the upper end that allows communication between the inside of the piston side oil chamber B and the inside of the Zaha chamber C, and the upper end opening of the communication hole 72 is closed. A leaf valve 73 is provided as a check valve. The leaf valve 73 serving as the check valve is biased downward by a spring 75 whose upper end is brought into contact with a stopper 74 that is engaged with the set bolt 70 . Further, the stopper 74 has a notch 74α formed therein.

The check valve 73 acts on the first
It is similar to the check valve 32 in the figure, and only allows oil to pass from the lower oil chamber to the upper oil chamber.

FIG. 6 shows a modification of the base valve section 6 and check valve 7 of FIG. 5, with respect to FIG. 1. This is a modification similar to the modification shown in FIG.

In other words, the compression side damping force generating section in the base valve case 60 is constructed in the same manner as in the case shown in FIG. is omitted, and instead, an oil passage 76 parallel to the communication hole 72 is bored in the thick upper end of the base valve case 60, and the lower end of the oil passage 76 is inserted into the base valve case 6o. The notch 73 of the leaf valve 73 is opened at the upper end of the oil passage 76.
α is facing. As a result of this button, the oil in the piston side oil chamber B flows into the base valve case 6o via the notch 73α of the leaf valve 73 and the oil passage 76, and the pressure side damping force generating portion in the base valve case 60 is caused to flow into the base valve case 6o. flows into. Then, a desired compression damping force is generated and a so-called high-cut action is performed in a region above an arbitrary frequency.

〔Effect of the invention〕

As described above, according to the present invention, a stable damping force lowering effect, that is, a high-cut effect can be obtained in a region above a given frequency, and, for example, the riding comfort in a vehicle can be improved.

Further, according to the present invention, the structure of the damping force generating section does not require any special processing inside or outside the piston nut, and especially when the damping force generating section is disposed inside the piston nut, it is so-called compact. This results in a reduction in the number of parts and the number of processing steps, which is economically advantageous.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional front view partially showing a hydraulic shock absorber according to an embodiment of the present invention, Fig. 2 is an enlarged mechanical diagram showing a damping force generating section according to the present invention, and Fig. 3 is a frequency change FIG. 4 is a longitudinal sectional front view showing an embodiment of a hydraulic shock absorber according to a modification of FIG. 1, and FIG. 5 is a partial diagram of a hydraulic shock absorber according to another embodiment. 6 is a longitudinal sectional front view showing an embodiment of a hydraulic shock absorber according to a modification of FIG. 5. FIG. 1...Cylinder, 2...Piston loft, 3...
Piston part, 4... Piston nut, 5... Damping force generating part, 40.61... Block, 42.65...
Check valve, 50.62...Leaf valve, 51
．． 63... Disk, 53j64... Ring part, 55,
67...Push valve, 56.68...Spring, 57.69...Spool, 58...Pressure chamber, A
...Rod side oil chamber, B...Piston side oil chamber, C...
・Reservoir room, D...gas chamber.

Claims (3)

[Claims] (1) In a hydraulic shock absorber that is formed to be able to reduce the damping force generated by the damping force generating part when the piston part slides in a region above a given frequency, the damping force generating part is an annular leaf valve. It is possible to generate a damping force of a predetermined magnitude by the deflection of the outer peripheral end of the leaf valve, and the outer peripheral end is generated by the pressing force applied to the inner peripheral end of the leaf valve. The leaf valve is formed to have a variable amount of deflection, and the pressing force is obtained by the internal pressure of a pressure chamber formed above the inner circumferential end of the leaf valve and communicating with the oil chamber in the cylinder via an orifice. The leaf valve is also characterized in that the internal pressure of the pressure chamber is transmitted to the spool that is in contact with the upper surface of the inner peripheral end of the leaf valve via a spring that expands and contracts as the push valve slides. Hydraulic shock absorber. (2) The hydraulic shock absorber according to claim 1, wherein the damping force generating section is housed in a piston nut that fixes the piston section to the tip of the piston rod inserted into the cylinder. (3) The hydraulic shock absorber according to claim 1, wherein the damping force generating section is housed in a base valve section disposed at the lower end of the cylinder.