JP2681496B2 - Hydraulic shock absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a hydraulic shock absorber that damps a load acting on a piston rod by a hydraulic braking force on a piston.

[Prior art]

Conventionally, there is one disclosed in Japanese Patent Application Laid-Open No. 61-189335, in which loads in opposite directions can be buffered by one hydraulic shock absorber. In this hydraulic shock absorber, a pair of pistons each having a built-in check valve are individually slidably fitted in the hydraulic cylinder body, and the piston rods of these pistons are slidably projected from both ends of the hydraulic cylinder body. The loads acting on the piston rods on opposite sides in opposite directions are individually buffered by the hydraulic braking force for each piston, and the other piston can be returned and slid by the hydraulic pressure at the time of buffering one piston. Is.

[Problems to be solved by the invention]

However, in this type, the return sliding of the piston is performed only by the hydraulic pressure that is pushed (excluded) by the piston on the opposite side, so that it becomes inoperable if oil leaks or air is mixed. Further, since the check valve is built in the piston, there is a problem that the structure is complicated and the cost becomes high. The present invention aims to solve such problems.

[Means for Solving the Problems]

In the hydraulic shock absorber of the present invention, between the pair of pistons that are individually slidably fitted in the hydraulic cylinder body, the push rod that can slide freely in the hydraulic cylinder body independently of them is interposed. It was made.

[Action]

Therefore, when one piston slides to the other piston side while performing a buffering action, the other piston is pushed by one piston through the push rod and returns and slides. Can be done.

【Example】

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view of the hydraulic shock absorber according to the present invention taken along the axis. The hydraulic cylinder body 1 has an inner cylinder 2 and an outer cylinder 3 fixed concentrically on both sides of the intermediate cover 4 one by one, that is, the inner cylinders 2 on both sides and the outer cylinders 3 on both sides via the intermediate cover 4. The outer ends of the inner cylinders 2 on both sides are liquid-tightly closed by the outer end covers 5 screwed into the outer cylinders 3, and the outer end of the outer cylinder 3 is liquid-tight by the collar portion 6 of the outer end of the inner cylinder 2. It is a closed one. Between the inner cylinder 2 and the outer cylinder 3 of each set, a front accumulation chamber 8 and a rear accumulation chamber 9 are formed which are partitioned by an annular convex portion 7 in the inner peripheral surface middle portion of the outer cylinder 3. And the front accumulation chamber 8 is the inner cylinder 2
It is communicated with the inside of the inner cylinder 2 through a communication hole 10 formed in the inner cylinder 2. Further, the rear storage chamber 9 is provided with a plurality of orifices 11 which are bored in the inner cylinder 2 at intervals in the axial direction, and correspond to the orifices 11 as shown in FIGS. 2 and 3 (developed view). The throttle groove 12 is dug on the inner peripheral surface of the annular convex portion 7 of the outer cylinder 3 by changing the depth in the circumferential direction. The outer peripheral surface of the inner cylinder 2 is dug so as to traverse these throttle grooves 12. It communicates with the inside of the inner cylinder 2 through the communication groove 13. At the same time, the front accumulation chamber 8 and the rear accumulation chamber 9 of each set are also communicated with each other through the communication groove 13. Further, the rear accumulation chambers 9 on both sides of the intermediate cover 4 are communicated with each other through a communication lateral hole 14 provided in the intermediate cover 4.
The front storage chamber 8, the rear storage chamber 9 and the inner cylinder 2 which communicate with each other in this manner are filled with an oil liquid. Note that
Reference numeral 15 is an oil filler plug, and 16 is a set screw for restricting rotation of the outer cylinder 3 with respect to the intermediate cover 4. Each inner cylinder 2 on both sides has a piston 17
Are slidably fitted. Piston rods 18 projecting from these pistons 17 have outer end covers 5 at both ends.
The liquid-tight protrusions are slidable in opposite directions from each other. In addition, a guide hole formed along the axis of the intermediate cover 4
A push rod 19 is pierced therethrough for free sliding. Both side portions of the push rod 19 project into the inner cylinders 2 on both sides in a liquid-tight manner from the guide holes 19. Rod receiving recesses 260 are provided on the inner end surfaces of the pistons 17 on both sides, and both end portions of the push rod 19 are pistons on both sides.
It is slidably and liquid-tightly fitted in the rod receiving recess 21 of 17. On both end faces of the push rod 19, there are rod receiving recesses.
Slots 22 'are provided for venting air when fitting into 21 and assembling, and each piston 17 further has an axial hole 22 drilled from the blind end of this rod receiving recess 21.
And a hole 23 that is orthogonal to this and opens on both sides of the peripheral surface on the piston rod 18 side. Next, the operation of this hydraulic shock absorber will be described. When a load is applied to the right piston rod 18 in the state shown in FIG. 1, the right piston 17 slides to the left while pushing the oil liquid in the right inner cylinder 2 and the push rod 19. As a result, the oil liquid in the inner cylinder 2 on the right side is allowed to flow through the orifice 12, the throttle groove 12 and the communication groove 13 of the inner cylinder 2.
To the front chamber 8 on the right side, further through the communication hole 10 to the front chamber of the right inner cylinder 19 formed on the front side of the piston 17, and to the rear chamber 9 on the right side. Can also flow into the rear storage chamber 9 on the left side through the communication lateral hole 14. The oil in the inner cylinder 2 on the right side is the orifice 1 as described above.
1, the right piston 1 due to the resistance when passing through the throttle groove 12
7 pushes the push rod 19 while performing a buffering action, and further pushes the left side piston 17 therethrough.
Therefore, the piston 17 on the left side is pushed leftward while the piston rod 18 is projected, and the oil liquid in the inner cylinder 2 on the left side flows into the communication hole 10, the front accumulation chamber 8, and the communication groove 13, and It also flows into the rear chamber of the inner cylinder 2 formed on the rear side of the left piston 17. After the left piston rod 18 projects in this way, when a load is next applied to it, the left piston 17 pushes the right piston 17 via the push rod 19 while performing a buffering action, contrary to the above. To do. The buffering action of the piston 17 due to the resistance when the oil liquid passes through the orifice 11 and the throttle groove 12 as described above is that the inner cylinder 2 is rotated with respect to the intermediate cover 4 to reduce the throttle gap between the orifice 11 and the throttle groove 12. Can be adjusted by changing. Moreover, since the adjustment can be performed separately in the inner cylinders 2 on both sides, the cushioning action of the left and right pistons 17 can be made different from each other. The hydraulic shock absorber according to the present invention is mounted on a moving body 24 that repeatedly reciprocates within a certain range as shown in FIG. 4, for example, and is used to buffer the moving body 24 at both ends of movement. In the figure, reference numeral 25 denotes a fixed position stopper that collides with the piston rod 18 and is adjustable in expansion and contraction.

【The invention's effect】

According to the hydraulic shock absorber of the present invention, when one piston slides toward the other piston side while performing a buffering action, the other piston is pushed by the one piston via the push rod and returns and slides. Even if oil leaks or air is mixed, it will not be disabled. Further, it is not necessary to return the piston with a return spring or the like, so that when the thrust is small, the return spring does not make it possible to determine the position. Further, since it is not necessary to incorporate a check valve in the piston, the structure is simple and the cost can be provided at a lower cost than before.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of an embodiment of the present invention, FIG. 2 is a horizontal sectional view taken along the line I--I of FIG. 1, FIG. 3 is a developed view of a portion for performing a diaphragm action, and FIG. It is explanatory drawing of an example. 1 …… hydraulic cylinder body, 17 …… piston, 18 …… piston rod, 19 …… push rod.

Claims (1)

(57) [Claims] 1. A pair of pistons are individually slidably fitted in a hydraulic cylinder main body, and piston rods of these pistons are slidably projected from both ends of the hydraulic cylinder main body so that the piston rods on both sides are mutually slidable. In the hydraulic shock absorber capable of individually damping the load acting in the opposite direction by the hydraulic braking force for each piston, and returning and sliding the other piston due to the buffering action by one piston, between the pair of pistons, A hydraulic shock absorber characterized by interposing a push rod capable of freely sliding in the hydraulic cylinder body independently of them.