JPS6332992Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic shock absorber that is attached to a vehicle such as an automobile and is suitable for use in damping vibrations.

FIG. 1 shows a hydraulic shock absorber according to the prior art.

In the figure, 1 is a cylinder, 2 is a piston rod protruding into the cylinder 1, and 3 is a piston fixed to the piston rod 2 and sliding along the inner wall of the cylinder 1. and,
There are two oil chambers A in the cylinder 1 due to the piston 3,
A damping force is generated in the oil flowing from one oil chamber to the other oil chamber when the piston 3 is displaced as an extension stroke or a contraction stroke, thereby producing a vibration damping effect. is configured to do so.

Next, the above-mentioned damping force generation mechanism will be explained. 5 and 6 indicate valve seats formed in an annular shape near the outer periphery on both sides of the piston 3; 7 and 8 indicate protrusions provided on the inner periphery on both sides of the piston 3; It is in a slightly protruding state.
Further, 9 and 10 are fitted into the piston rod 3,
Disk valves 11 and 12 whose inner peripheral edges abut against the protrusions 7 and 8, respectively, and whose outer peripheral edges abut against the valve seats 5 and 6, separate the respective disc valves 9 and 10 from the valve seats 5 and 6, respectively. Spacers 13 and 14 allow for deformation in the sitting direction, and 13 and 14 indicate regulating portions that regulate the degree of opening of each of the disc valves 9 and 10, and the disc valve 9, the spacer 11,
The restriction part 13 is held between the piston 3 and a stepped part 2A formed on the piston rod 2, and the disc valve 10, the spacer 12, and the restriction part 14 are held between the piston 3 and a lock nut 15 screwed onto the piston rod 2. has been done. One of the disc valves 9 and 10 is made up of two overlapping disks, and the other disc valve 10 is made up of three overlapping disks. And disc valve 9,1
0 is in contact with the protrusions 7, 8 and the valve seats 5, 6, respectively, thereby forming annular oil chambers 16, 1 between the disc valves 9, 10 and each side of the piston 3.
7 is formed. Reference numerals 18 and 19 are communication passages provided in the piston 3, with one communication passage 18 communicating between the oil chamber A and the annular oil chamber 17, and the other communication passage 19 communicating between the oil chamber B and the annular oil chamber 17. The communication passages 18 and 19 are provided at an angle with respect to the axis of the piston 3. Furthermore, the innermost disk 10 of the disk valve 10
A plurality of cutouts 20, 20, . . . are formed in A so as to have a throttle and constantly communicate the oil chamber 17 and the oil chamber B.

The hydraulic shock absorber according to the prior art has the above-mentioned structure, and its operation will be explained next.

Suppose now that the piston 3 is displaced together with the piston rod 2 in the direction of the arrow X in the figure. As a result, the pressure inside the oil chamber A becomes high, and a pressure difference is generated between the oil chamber A and the oil chamber B. Therefore, the oil in the oil chamber A flows from the communication passage 18 into the annular oil chamber 17 and into the oil chamber B through the notch 20 provided in the disc valve 10. Since the flow path area of the notch 20 is constricted to form an orifice, a predetermined damping force acts upon passage through this portion. When the piston 3 is displaced at high speed, the pressure within the oil chamber A increases, and this pressure is guided into the annular oil chamber 17 and acts on the disc valve 10. And this disc valve 1
When the pressure acting on the disc valve 10 becomes greater than the spring force of the disc valve 10, its outer peripheral edge portion deforms and separates from the valve seat 6. As a result, the annular oil chamber 1
7 to the oil chamber B increases, and the damping force characteristics change in two stages.

On the other hand, when the piston 3 is displaced in the direction of the arrow Y, contrary to the above, the same operation as described above is performed. However, since the disc valve 10 uses three discs and the disc valve 9 uses two discs, the opening pressure of the disc valve 10 is higher than that of the disc valve 9, and therefore the piston 3 moves in the X direction. The extension stroke of displacement exhibits higher damping force characteristics than the contraction stroke of displacement in the Y direction.

As described above, in the case of the hydraulic shock absorber according to the prior art, the damping force characteristics are different between the case where the oil flow path is provided by the notch 20 and the case where the oil flow path is provided by the notch 20, and the case where the oil flow path is provided by the notch 20.
Since the damping force characteristics change after the valve is opened, the vibration damping effect can be smoothly performed when the valve is installed in a vehicle or the like.

However, the above-mentioned hydraulic shock absorber has a communication passage 1 that opens on one side to the annular oil chambers 17 and 16, respectively.
Since the other side of the valve seats 6 and 5 is opened to the oil chambers A and B at the outer peripheral side of the valve seats 6 and 5, each of the communication passages 18 and 19 must be bored diagonally. There were drawbacks as described in.

First of all, the piston 3 has an oblique communication passage 18,
It is difficult to drill 19, and its workability is poor.
There were drawbacks that led to high costs. Second, due to the dimensions of the piston 3, the cross-sectional area of the communicating passages 18, 19 cannot be made large, and due to problems with their strength, it is not possible to drill a large number of communicating passages 18, 19. As a result, the communicating passages 18 and 19 act as throttles, and there is also the drawback that a hydraulic shock absorber with low damping force characteristics cannot be formed. Thirdly, because the communication passages 18 and 19 are constricted, it is not possible to create a versatile piston that can be used for both hydraulic shock absorbers with low damping force characteristics and hydraulic shock absorbers with high damping force characteristics. There were also drawbacks.

The present invention was made in view of the problems of the prior art described above, and the structure adopted by the present invention includes a piston rod inserted into a cylinder, and a piston rod provided on the piston rod that connects the inside of the cylinder.
a piston defining two oil chambers; a valve seat formed in an annular shape at each end of the piston;
A hydraulic shock absorber comprising an extension side disk valve and a contraction side disk valve provided on both sides of the piston so as to sit on and off each valve seat, the disk valve being perforated in the axial direction of the piston, and having both ends connected to each of the valves. an extension-side communication passage and a contraction-side communication passage that open toward the inner peripheral side of the seat; and an extension-side communication passage that is provided between the disc valve and one side of the piston so as to support the inner peripheral edge of the reduction disc valve; a retainer that is provided with an oil passage that closes the opening of the disc valve and communicates the contraction side communication passage with one of the oil chambers; another retainer provided between the piston and the other side and having an oil passage bored therein that closes the opening of the contraction side communication passage and communicates the extension side communication passage with the other oil chamber; The oil hole is bored and communicates the expansion side communication passage with one oil chamber, and the oil hole communicates the contraction side communication passage with the other oil chamber.

With this configuration, when the piston is in the extension stroke, one oil chamber is at high pressure, so high-pressure oil is routed from the one oil chamber to the oil hole, the extension side communication path, and the oil path of the other retainer. It flows toward the extension-side disc valve through the valve, opens the disc valve, and generates a predetermined damping force. Also, when the piston is in the contraction stroke, the other oil chamber becomes high pressure, so high-pressure oil flows from the other oil chamber to the oil hole, the contraction side communication passage, and the oil passage of one retainer to the contraction side disc valve. The disc valve is opened and a predetermined damping force is generated.

Embodiments of the present invention will be described below based on the drawings.

First, FIGS. 2 to 7 show a first embodiment of the present invention, and the same components as in FIG. 1 are designated by the same reference numerals and their explanations will be omitted. 31 indicates a piston, and the piston 31 has a large diameter portion 31A that comes into sliding contact with the inner wall of the cylinder 1, and small diameter portions 31B, 31 formed on both sides of the large diameter portion 31A.
It has C. And the small diameter portions 31B, 31C
Annular valve seats 32, 33 are formed on the outer circumferential side of the valve seats 32, 33, and recesses 34, 35 are formed on the inner circumferential side of each valve seat 32, 33.

Reference numerals 36 and 37 indicate communication passages formed in the axial direction of the piston 31, and two communication passages 37 and 38 are provided at positions 180° out of phase with each other, as shown in FIG. Both ends of these communication passages 36 and 37 open into the recesses 34 and 35. Further, large diameter portions 36A and 37A are formed on the side of the communication passage 36 facing the oil chamber A and the side of the communication passage 37 facing the oil chamber B, respectively.

Next, 38 and 39 indicate retainers that close the communication passages 36 and 37, and the retainers 38 and 39 are fitted into the recesses 34 and 35 of the piston 31, respectively. Each retainer 38, 39 has protrusions 38A, 39A radially inward on its outer surface side.
The disc valves 9, 10 have their inner peripheries in contact with the protrusions 38A, 39A, respectively, and their outer peripheries in contact with the valve seats 32, 33, whereby the disc valves 9, 10 and the retainer are in contact with each other. 3
Annular oil chambers 40 and 41 are formed between the oil chambers 8 and 39. The retainer 38 also has a communication passage 37.
an oil passage 42 that communicates between the annular oil chamber 40 and the annular oil chamber 40;
However, the retainer 39 is also provided with a plurality of oil passages 43 for communicating between the communication passage 37 and the annular oil chamber 41. On the other hand, retainers 38 and 39
has a communication passage 36 radially outward on its inner surface side,
Positioning protrusions 38B and 39B protruding into the large diameter portions 36A and 37A of 37 are formed, and each retainer 38 and 39 is positioned by each of the protrusions 38B and 39B.

Further, 44 and 45 are ring grooves formed in the small diameter portions 31B and 31C of the piston 31, respectively, and each of the ring grooves 44 and 45 is a ring-shaped groove having a smaller diameter than the large diameter portions 36A and 37A of the communication passages 36 and 37. ,
The large diameter portion 36A,
37A is cut out to form oil holes 46 and 47. Therefore, the oil chambers A and B are constantly communicated with the communication passages 36 and 37 by the respective oil holes 46 and 47.

The hydraulic shock absorber according to the present invention has the above-described configuration, and during the extension stroke in which the piston 31 is displaced in the direction of the arrow X in FIG.
The oil inside flows through the oil hole 46, the communication path 36, the oil path 43, and the annular oil chamber 33 from the notch 20 of the disk 10A, which serves as an orifice, into the oil chamber B, and at this time, it causes damping against the piston 31. Force acts.
When the piston 31 is displaced at high speed, the pressure inside the oil chamber A becomes high and the pressure inside the annular oil chamber 41 also becomes high, so this pressure acts on the disc valve 10 and causes the disc valve 10 to open. Oil room A
The flow path area from the oil chamber B to the oil chamber B increases, and the damping force characteristics change.

On the other hand, in the case of the contraction stroke in which the piston 31 is displaced in the direction of the arrow Y in FIG.
The oil inside is contained in the notch 20 of the disc 10A, the annular oil chamber 41, the oil passage 43, the communication passage 36, and the oil hole 46.
The oil flows into the oil chamber A through the notch 20, and a damping force is generated when it flows through the notch 20. When the piston 31 moves at high speed, the pressure inside the oil chamber B becomes high, and this pressure is applied to the oil hole 47, the communication passage 37, the oil passage 42, and the annular oil chamber 4.
0 to the disc valve 9 to open the disc valve 9.
The flow path area increases and the damping force changes. These operations are not particularly different from those of the prior art described above.

However, since the communicating passages 36 and 37 are formed in the axial direction of the piston 31, they are easy to process, and the area of the passages can be increased, and a plurality of them can be provided. For this reason, the communication passages 36 and 37 do not serve as constrictions in the flow of oil. Therefore, by changing the passage area of the oil passages 42, 43 formed in the retainers 38, 39, desired passage resistance can be generated in the oil flowing through the oil passages 42, 43. Also, the protrusions 38A, 3 of the retainers 38, 39
By setting the thickness of 9A to an appropriate value within a range that does not protrude from the valve seats 32, 33, a desired initial load can be applied to the disc valves 9, 10, so that the opening pressure of each disc valve 9, 10 can be increased. can also be set freely. Therefore, without making any changes to the piston 31, the damping force characteristics of the hydraulic shock absorber can be freely changed by simply designing the shapes of the retainers 38 and 39 and the passage areas of the oil passages 42 and 43 as appropriate. This allows the piston 31 to have versatility.

Next, FIGS. 8 to 11 show a second embodiment of the present invention. In the figures, the same components as those shown in the first embodiment are denoted by the same reference numerals and explained. shall be omitted. However,
In this embodiment, a hydraulic shock absorber is shown in which the damping force characteristics on the extension side and the damping force characteristics on the contraction side of the piston 31 are independently set. For this purpose, the large diameter portions 3 of the communication passages 36, 37
6A, 37A are provided with one-way valves 51, 52, and the one-way valves 51, 52 are always supported by springs 53, 4.
The oil holes 46 and 47 are closed by the force. Then, depending on the displacement of the piston 31, the oil chamber A or B
When the pressure becomes high, the one-way valve 51 or 5
2 is opened, and the oil chamber A and the communication passage 36 or the oil chamber B and the communication passage 37 can be communicated with each other. Further, the disc 9A inside the disc valve 9 is provided with a plurality of notches 55, 55, . . . which have a throttle and constantly communicate the oil chamber 40 and the oil chamber B.

In the figure, reference numeral 56 indicates a positioning pin 56 protruding from the retainer 38, and the pin 56 is fitted into a recess 57 formed in the end surface of the piston 31. The retainer 39 also has a pin similar to the pin 56 and a recess similar to the recess 57 described above on the side surface of the piston 31 facing the pin.

The present embodiment is configured as described above, and its operation will be explained next. First, when the piston 31 is displaced in the direction of the arrow X in FIG. 8 and enters an extension stroke, the pressure inside the oil chamber A becomes high. When the pressure inside this oil chamber A becomes equal to or higher than a predetermined value, the one-way valve 51 opens,
The oil in the oil chamber A is caused to flow into the communication path 36. When the opening amount of this one-way valve 51 is smaller than the passage area of the notch 20, the one-way valve 51 acts as a constriction part, and when the oil passes through this part, the first stage damping force is applied. to occur. Next, when the pressure in the oil chamber A becomes high and the opening amount of the one-way valve 51 becomes larger than the passage area of the notch 20, the notch 20 becomes a constriction part and the damping force characteristics change. And oil chamber A
When the internal pressure becomes even higher, the disc valve 10 opens, the flow path area from the oil chamber A to the oil chamber B increases, and the damping force characteristics change in three stages. in this case,
The oil in the oil chamber A flows into the annular oil chamber 40 through the notch 55 and flows into the communication passage 37 through the oil passage 42, but since the one-way valve 52 is in the closed state, The oil in the communication path 37 does not flow into the oil chamber B.

On the other hand, when the piston 31 is displaced in the direction of the arrow Y in FIG.
Next, a second stage of damping force is generated by the notch 55, and a third stage of damping force is generated by opening the disc valve 9, and the damping force characteristics change in three stages.

In addition, in each of the above-mentioned embodiments, the retainer 3
Although the projections 38A and 39A of the retainers 8 and 39 have been described as being integrally formed, the projections 38A and 39A can be formed separately from the retainers 38 and 39. In addition, the number of discs in disc valves 9 and 10 is 2 and 3 as shown in the drawing.
The number of discs is not limited to one, but any suitable number may be used, and the number of discs on both sides of the disc valve may be the same. Furthermore, although the discs 9 and 10 are provided with notches 20 and 55, for example, one
When a disk valve is formed from a single disk, a through hole may be used instead of the above-mentioned notch. Furthermore, in the second embodiment, the springs 53, 5
If the spring force of 4 is reduced, the one-way valves 51 and 52
As soon as the oil chambers A and B become high pressure, they open fully, so the damping force characteristics change in two stages. Furthermore, if only the one-way valve 51 is provided and no one-way valve is provided in the large diameter portion 37A of the communication path 37,
During the contraction stroke of the piston 31, the notches 20 and 55 serve as passage areas, and low damping force characteristics can be obtained during the contraction stroke. Furthermore, if the piston 31 or the one-way valves 51, 52 are provided with orifices that communicate the oil chambers A, B with the communication passages 36, 37 through a restriction, the damping force characteristics can be changed in four stages.

As described in detail above, according to the hydraulic shock absorber according to the present invention, since the communication passage is formed in the axial direction of the piston, the communication passage can also be formed at the same time when the piston is molded, so that the machining is easy. This becomes easy and the flow area of the communication path can be increased. Since a retainer having an oil passage for applying the pressure in the communication passage to the disc valve is provided between the piston and the disc valve, it is only necessary to change the shape of the retainer and the passage area of the oil passage. The damping force characteristics of the hydraulic shock absorber can be changed, and the same piston can be used for both low damping force characteristic hydraulic shock absorbers and high damping force characteristic hydraulic shock absorbers, making it a versatile piston. It has various effects such as being able to

[Brief explanation of the drawing]

FIG. 1 is a partial longitudinal sectional view showing a conventional hydraulic shock absorber, FIGS. 2 to 7 show a first embodiment of the present invention, and FIG. 2 is a partial longitudinal sectional view of the hydraulic shock absorber. , Fig. 3 is an external view of the piston in Fig. 2 with some parts omitted, Fig. 4 is a left side view of Fig. 3 with the retainer removed, Fig. 5 is an external view of the retainer, and Fig. 6 is an external view of the piston in Fig. 2. 5 is a right side view of FIG. 5, FIG. 7 is a plan view of FIG. 5, FIGS. 8 to 11 show a second embodiment of the present invention, and FIG. 8 is a partial longitudinal sectional view of a hydraulic shock absorber. Figure 9 is a sectional view in the - arrow direction of Figure 8, and Figure 10 is the 8th cross-sectional view.
FIG. 11 is a left side view of the piston shown in the figure, and FIG. 11 is a left side view of the retainer shown in FIG. 1...Cylinder, 2...Piston rod, 9,
10... Disc valve, 31... Piston, 3
2, 33... Valve seat, 36, 37... Communication path,
38, 39... retainer, 42, 43... oil path,
46, 47...Oil hole, 51, 52...One-way valve.

Claims (1)

[Claims for Utility Model Registration] A piston rod inserted into a cylinder, and a piston rod provided on the piston rod that connects the inside of the cylinder.
a piston defining two oil chambers; a valve seat formed in an annular shape at each end of the piston;
A hydraulic shock absorber comprising an extension side disk valve and a contraction side disk valve provided on both sides of the piston so as to sit on and off each valve seat, the disk valve being perforated in the axial direction of the piston, and having both ends connected to each of the valves. an extension side communication passage and a contraction side communication passage opening on the inner peripheral side of the seat; and a communication passage provided between the disc valve and one side of the piston so as to support the inner peripheral edge of the reduction side disc valve; a retainer, which is provided with an oil passage that closes the opening of the passage and communicates the contraction side communication passage with one of the oil chambers; another retainer provided between the other side of the piston and having an oil passage bored therein that closes the opening of the contraction side communication passage and communicates the extension side communication passage with the other oil chamber; and the piston. 1. A hydraulic shock absorber comprising: an oil hole that is drilled in and that communicates the extension-side communication passage with one oil chamber; and an oil hole that communicates the contraction-side communication passage with the other oil chamber.