JPH0442594Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a hydraulic shock absorber, and more particularly to a hydraulic shock absorber equipped with a piston having dual inner and outer oil passages in the radial direction.

(Prior Art) In this type of hydraulic shock absorber, the valve mechanism that generates the damping force on the rebound side is usually provided for the inner oil passage (for example,
(See Publication No. 21834). This applies not only to single-effect hydraulic shock absorbers that generate damping force only on the extension side, but also to double-effect hydraulic shock absorbers that generate damping force on both the extension and compression sides. This is because the valve mechanism itself becomes large-scale.

By the way, in the case of hydraulic shock absorbers, when it is desired to change the damping force characteristics, it is advantageous to change the pressure receiving area of the valve that closes the oil passage in order to obtain the desired damping force characteristics. However, in the case of a hydraulic shock absorber that incorporates a piston with double oil passages, as described above, when attempting to expand the opening of the inner oil passage in order to expand the pressure receiving area of the valve, the installation space for the outer oil passage is correspondingly increased. will be narrowed down. For this reason, conventionally, as shown in Japanese Patent Publication No. 56-8216, for example, a valve mechanism including a piston is divided into parts to ensure a predetermined oil passage.

(Problems to be solved by the invention) However, according to the countermeasures shown in the above-mentioned Japanese Patent Publication No. 56-8216, the number of parts not only increases, but also
There were problems in that the assembly structure was complicated, requiring a large number of man-hours for assembly, and the economic burden was also large. In addition, if you try to avoid this problem, the above-mentioned
As shown in Publication No. 21834, the general method of supporting the valve with a coil spring has to be adopted, and in this case, the damping force characteristics must be changed by changing the spring constant of the coil spring. , it becomes difficult to obtain desired damping force characteristics.

(Means for solving the problems) In order to solve the above-mentioned conventional problems, the present invention
A first oil passage communicating the two chambers in the cylinder on the outside in the radial direction, and a second oil passage communicating the two chambers on the inside in the radial direction.
On one end side of the piston, each having an oil passage of
A suction valve that closes the first oil passage and always opens the second oil passage on the extension side, and a third oil that communicates with the second oil passage at the other end of the piston. a retainer having a passageway and an annular groove extending radially outward an opening on a side opposite to the piston of the third oil passage; A disc valve that generates a damping force on the side is disposed in a fixed state on the inner peripheral edge, and a plate having a hole that determines the passage area of the second and third oil passages is interposed between the piston and the retainer. The gist is that the system is configured to be equipped with

In the present invention, it is preferable that the disc valve is formed from a laminated valve made of stacked flat plates.

(Function) In the hydraulic shock absorber having the above configuration, since the retainer is connected to the lower end of the piston, even if the opening of the oil passage of this retainer is expanded radially outward, this expansion will cause the outer oil passage of the piston to open. There is no interference, and the pressure receiving area of the disc valve that generates the damping force can be easily changed to a desired size.

(Example) Hereinafter, an example of the present invention will be described based on the accompanying drawings.

1 to 3 show the basic structure of a hydraulic shock absorber according to the present invention. In these figures, 1 is a cylinder, 2 is a piston that is slidably housed in the cylinder 1, and the piston 2 is
is integrally attached to the lower end small diameter portion 3a of the piston rod 3, which extends to the outside through a rod guide (not shown) attached to the upper end opening of the cylinder 1, together with other elements described later. The piston 2 has a first oil passage 4 on its radially outer side that communicates the upper chamber A and the lower chamber B, and a second oil passage 4 that also communicates the upper chamber A and the lower chamber B on its radially inner side.
It has an oil passage 5 of. A suction valve 6 that closes the first oil passage 4 is provided at the upper part of the piston 2.
is located. That is, the suction valve 6 is connected to a spring receiver 7 attached to the piston rod 3.
Its inner peripheral edge is pressed against the end surface of the piston 2, and is always urged to close the first oil passage 4 by a coil spring 8, one end of which is seated on the spring receiver 7. This suction valve 6 also keeps the second oil passage 5 open at all times by having long holes 6a, 6a (Fig. 2) provided in the circumferential direction facing the second oil passage 5. ing.

On the other hand, a retainer 10 having a third oil passage 9 communicating with the second oil passage 5 is arranged below the piston 2 . The retainer 10 has an appropriate height projecting downward from the lower end surface 2a of the piston 2, and is provided with an annular groove 11 at its lower end that expands the opening of the third oil passage 9 radially outward. .
Reference numeral 12 denotes a disc valve that engages with the end face of the retainer 10 and closes the third oil passage 9 including the annular groove 11, and its inner peripheral edge is connected to the end face of the retainer 10 by a spacer 14 attached to the piston rod 3. is being held down by This disc valve 12
is constructed as a so-called stacked valve by stacking a plurality of ring-shaped flat plates 13, 13, . . . . Further, one flat plate 13 of the disc valve 12 located on the retainer 10 side has a plurality of notches 13a on its outer peripheral edge. This notch 13a functions as an orifice when the disc valve 12 is closed, and
A slight flow of oil is allowed through the oil passages 5 and 9.

15 is a retaining ring attached to the piston rod 3 and backs up the spacer 14; 16 is a nut screwed onto one end of the piston rod 3; the elements above the spacer 14 are attached to the nut 1;
By receiving a tightening force of 6 through the retaining ring 15, the piston rod 3 is fixed to the small diameter portion 3a of the piston rod 3 all at once.

With such a configuration, when the piston 2 moves upward (operates in the extension side), the suction valve 6 closes the first oil passage 4, and the oil in the upper chamber A flows through the suction valve 6. It flows into the second oil passage 5 and the third oil passage 9 through the long hole 6a. While the piston speed is low, the oil that has flowed in flows into the lower chamber B through the annular groove 11 of the retainer 10 and the notch 13a (orifice) of the disc valve 12, and during this period, a predetermined damping force is generated. On the other hand, when the piston speed increases, the entire disc valve 12 is bent and the third oil passage 9 including the annular groove 11 is opened, and a large amount of oil in the upper chamber A flows into the lower chamber B. During this time, the disc valve 12 is bent. A damping force is generated according to the opening degree of 12.

The opening of the third oil passage 9 is expanded radially outward due to the presence of the annular groove 11, thereby increasing the pressure receiving area of the disc valve 12 and opening the disc valve 12. The valve becomes easier. In other words, as the spring constant of the disc valve 12 becomes smaller, the damping force on the extension side is reduced, and desired damping force characteristics can be easily obtained. Note that when the piston 2 moves downward (actuates toward the contraction side), the disc valve 12 closes the second and third oil passages 5 and 9, so the oil in the lower chamber B is drained from the first oil passage 4. When the suction valve 6 is opened, the oil flows into the upper chamber A, but the first oil passage 4 is not affected by the disc valve 12, and a predetermined flow of oil can be ensured.

In the above basic structure, since a laminated valve is used as the disc valve 12, the damping force characteristics can be changed by changing the number of flat plates 13, and together with the above change in the pressure receiving area, the selection of changing the damping force on the expansion side can be made. The width can be further expanded. Further, by using the disc valve 12, the coil spring can be omitted, and the sound of the coil spring hitting the spring receiver is also eliminated, which helps to eliminate noise.

Therefore, in this embodiment, as shown in FIGS. 4 and 5, the piston 2 and the retainer 10 are
By interposing a plate 20 having holes 21, 21, . Therefore, it is also possible to change the damping force characteristics on the rebound side, and in this case, the range of selection of the damping force characteristics on the rebound side can be easily expanded while leaving the piston 2 and the retainer 10 as they are. .

Further, the disc valve 12 in the above embodiment
Of course, a single-layer valve may be used instead of a laminated valve.

Further, in the above embodiment, the inner circumferential edge of the suction valve 6 is fixed, but the present invention also includes a structure in which the suction valve 6 is arranged to be freely movable in the axial direction.

(Effects of the invention) As explained above in detail, the hydraulic shock absorber according to the invention has a retainer connected to the piston to expand the pressure receiving area of the disc valve that generates the damping force on the extension side. Therefore, the damping force characteristics can be changed by changing the pressure receiving area without interfering with the outer oil passage of the piston, and the damping force characteristics can also be changed by selecting a plate with an appropriately sized hole. This not only makes it possible to easily and reliably change the damping force characteristics, but also has the effect of expanding the range of selection.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the basic structure of the hydraulic shock absorber according to the present invention, Fig. 2 is a plan view of a suction valve, which is a part of it, and Fig. 3 is a plan view of a disc valve, which is also a part of it. A plan view, FIG. 4 is a sectional view showing an embodiment of the present hydraulic shock absorber, and FIG. 5 is a plan view of a plate that is a part thereof. DESCRIPTION OF SYMBOLS 1... Cylinder, 2... Piston, 3... Piston rod, 4... First oil passage, 5... Second oil passage, 6... Suction valve, 9... Third oil passage, 10 ... Retainer, 11 ... Annular groove, 1
2... Disc valve, 13... Flat plate, 14...
Spacer.

Claims (1)

[Scope of utility model registration request] The first chamber communicates the two chambers in the cylinder radially outward.
an oil passage on one end side of the piston, each having a second oil passage communicating the two chambers on the inside in the radial direction, closing the first oil passage on the extension side and always leaving the second oil passage open. a suction valve is disposed at the other end of the piston, and has a third oil passage communicating with the second oil passage, and an opening of the third oil passage on the side opposite to the piston is expanded radially outward. A retainer having an annular groove is connected to the retainer, and a disc valve that closes the third oil passage including the annular groove and generates a damping force on the extension side is disposed in the retainer with its inner peripheral edge fixed, and A hydraulic shock absorber, characterized in that a plate having holes for determining passage areas of the second and third oil passages is interposed between the piston and the retainer.