JPH0547878Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a stay damper that can increase the holding force during extension and cutting.

[Conventional technology]

If the stay damper does not have sufficient holding force when fully extended, for example, when the stay damper is used to keep the rear door of a car open, the rear door may suddenly close due to a slight external force such as wind. This is extremely dangerous and can lead to unexpected accidents.

Therefore, as a structure for ensuring the holding force when the stay damper is extended and cut, there has been a proposal as shown in FIG. 6, for example.

That is, the piston rod 2 inserted into the cylinder 1 so as to be freely retractable has a piston part 3 that is slidably housed in the cylinder 1 at its tip (right end in the figure). However, the portion near the tip is a bulged portion whose diameter is expanded by interposing a collar 4 or the like, for example.

On the other hand, the cylinder 1 is formed so that the protruding and retracting end is in a sealed state, and a packing 5 is disposed on the inner periphery of the protruding and retracting end, and the inner periphery of the packing 5 is connected to the piston rod. It is in sliding contact with the outer periphery of 2.

A stopper 6 is fixedly disposed inside the cylinder 1 in the vicinity of the protruding and retracting end, and when the stay damper approaches the fully extended state, the outer periphery of the collar 4 etc. slides on the inner periphery of the stopper 6. It is said that it will be in touch.

A sealing member 7 is disposed inside the vicinity of the protruding and retracting end, that is, between the stopper 6 and the seal 5, and when the stay damper approaches the fully extended state, the sealing member 7 It is assumed that the outer periphery of the collar 4 etc. is in sliding contact with the periphery.

Furthermore, the space between the seal member 7 and the packing 5 is defined as a negative pressure chamber R when the stay damper is extended or extended.

Therefore, when the piston rod 2 makes a large stroke in the extension direction (to the left in the figure) inside the cylinder 1 and the stay damper reaches the fully extended state (the state shown in the figure), the stopper 6 prevents the further stroke of the piston rod 2. This is prevented, and the stay damper becomes fully extended.

When the stay damper is compressed from this state due to the action of an external force such as wind, the piston rod 2 is stroked in the compression direction, and therefore, a negative pressure is created in the negative pressure chamber R. A repulsive force is generated in the negative pressure chamber R that prevents the piston rod 2 from stroking in the compression direction, and this repulsive force becomes a holding force when the stay damper is extended or fully extended.

Therefore, when setting the stay damper to increase the holding force when it is fully extended, it is necessary to select the material and structure of the seal member 7, or use a plurality of seal members 7, etc. to increase the sealing force. It is enough to improve performance.

[The problem that the idea aims to solve]

However, the above-mentioned conventional proposal has the disadvantage that it tends to increase the cost of the stay damper.

That is, in the above conventional proposal, the holding force when the stay damper is fully extended, that is, the negative pressure in the negative pressure chamber R, is partially related to the sealing performance of the seal member 7. However, since an expensive sealing member 7 with improved sealing performance or a plurality of sealing members 7 are interposed, the cost of the final product of the stay damper tends to increase unnecessarily.

In addition, in the above conventional proposal, the compression operation force when releasing the extended state of the stay damper is proportional to the selection of the seal member 7 so as to generate a high negative pressure in the negative pressure chamber R. There is also the disadvantage that the stay damper tends to lack so-called operability as the stay damper becomes larger.

In view of the above-mentioned circumstances, this invention provides a new stay damper that not only does not have a fixed operability but also avoids the use of expensive sealing members and avoids the unnecessary increase in costs. The purpose is to

[Means to solve the problem]

In order to achieve the above object, the structure of the stay damper according to this invention is such that a piston rod is inserted into the cylinder so as to be retractable, and a rod-side oil chamber is defined in the cylinder by a piston section connected to the tip of the piston rod. In the stay damper, the stay damper has a negative pressure chamber defined by a stopper in the rod-side oil chamber, and the stopper is provided with a port that communicates the negative pressure chamber and the rod-side oil chamber. At the same time, a stop rubber is adjacent to the end face of the stopper on the rod side oil chamber side so as to be able to be seated and removed, and the opening of the port on the rod side oil chamber side is formed so as to be closed when the stopper is adjacent to the stop rubber. It is characterized by:

[Effect]

Therefore, until the piston rod makes a large stroke in the extension direction in the cylinder and the stay damper is fully extended, the hydraulic oil in the negative pressure chamber flows out to the rod side oil chamber through the port, and the stay damper expands. Enables disconnection.

On the other hand, when the stay damper is in the fully extended state, the stop rubber slides and is brought into contact with the end surface of the stopper on the rod side oil chamber side, and the stop rubber is moved to the end surface of the stopper on the rod side oil chamber side, and
Further stroke of the stay damper is prevented, and the stay damper becomes fully extended.

The opening of the port is closed by the stop rubber adjoining the end face of the stopper on the rod side oil chamber side.
The flow of hydraulic oil between the negative pressure chamber and the rod-side oil chamber, especially the flow of hydraulic oil into the negative pressure chamber, is prevented with high closing performance.

Therefore, even if the stay damper is compressed from the fully extended state due to the action of an external force such as wind and the piston rod is stroked in the compression direction, the inflow of hydraulic oil into the negative pressure chamber will be limited to the port. Therefore, a negative pressure is generated in the negative pressure chamber, that is, a repulsive force that prevents the piston rod from stroking in the compression direction, and this repulsive force is used as a holding force to prevent the stay damper from extending or opening. maintain the condition.

When the stay damper in the fully extended state is compressed with a force stronger than the negative pressure, the expanded diameter portion of the piston rod slides on the inner circumference of the stopper, and the inner circumference of the stopper and the outer circumference of the piston rod slide. Hydraulic oil flows into the negative pressure chamber through the gap, the negative pressure phenomenon in the negative pressure chamber is released, the piston rod is allowed to stroke in the compression direction, and the stay damper is returned to its compressible state. .

〔Example〕

Hereinafter, this invention will be explained in detail based on the illustrated embodiments.

As shown in FIG. 1, a stay damper according to an embodiment of this invention has a piston rod 2 inserted into a cylinder 1 so as to be able to protrude and retract, and a piston part 3 connected to the tip of the piston rod 2 to move the piston rod 2 into the cylinder 1. Rod side oil chamber A and piston side oil chamber B inside
It is formed by forming a partition.

In this embodiment, although not shown, a gas chamber partitioned by a free piston is formed in the pistonner side oil chamber B, and the stay damper is always extended by the gas pressure in the gas chamber. energized in the direction.

The protruding and retracting end of the cylinder 1 is closed by a cap 7 and a packing 5 arranged in parallel on its inner periphery, and the outer periphery of the piston rod 2 is brought into sliding contact with the inner periphery of the cap 7 and packing 5. It is formed to be in a predetermined sealed state.

The cap 7 is fixed in a predetermined position by caulking the outer periphery of the protruding and retracting end of the cylinder 1, and the packing 5 has a metal 5a on the surface adjacent to the cap 7.

A stopper 6 is disposed inside the cylinder 1 in the vicinity of the protruding and retracting end thereof, and is fixed at a predetermined position by caulking the outer periphery of the cylinder 1 .

The stopper 6 has an insertion hole for the piston rod 2 in its axial center, and the stopper 6 has an insertion hole for the piston rod 2, which will be described later.
It has a through hole 6a which serves as a sliding contact hole for the enlarged diameter portion of the hole, and also has a port 6b opened in the thick portion thereof.

As shown in FIG. 2, the port 6b is connected to the negative pressure chamber R defined by the stopper 6, the packing 5, and the piston rod 2 when the stay damper is fully extended. , allowing communication with the rod side oil chamber A.

A sealing O-ring 60 that comes into sliding contact with the expanded diameter portion of the piston rod 2 is interposed on the inner periphery of the stopper 6 together with a back-up spring 61, and on the outer periphery of the stopper 6, the cylinder 1 An O-ring 62 adjacent to the inner periphery is interposed.

By the way, a stop rubber 8 is adjoined to the end face 6c of the stopper 6, which is on the rod side oil chamber A side, and can be moved in and out of position.When the stop rubber 8 is adjacent to the end face 6c, the rod side oil of the port 6b is The opening on the chamber A side is formed to be closed.

A through hole 8a is bored on the inner circumferential side of the stop rubber 8;
As shown in FIG. An appropriate distance is formed between the outer periphery of the expanded diameter portion and the outer periphery of the expanded diameter portion.

The piston rod 2 has a spigot part 2a at its tip.
A collar 4 is interposed therein, and a piston part 3 is connected to the collar 4.

The collar 4 increases the diameter of the portion of the piston rod 2 near the piston portion 3. That is, it is provided for the purpose of forming an enlarged diameter portion, and in this embodiment, it is fixed by tightening a piston nut 20 that fixes the piston portion 3 to the piston rod 2.

In addition, the tip spigot part 2 of the piston rod 2
A seal ring 21 adjacent to the inner circumference of the collar 4 is interposed on the outer circumference of a.

The piston portion 3 includes a piston body 30, a valve 31, and a valve stopper 32.

The piston main body 30 is formed so that its outer periphery is in sliding contact with the inner periphery of the cylinder 1, and is interposed in the tip spigot portion 2a of the piston rod 2.

The piston main body 30 has a port 30a formed in the thick part thereof so as to pass through the thick part in the axial direction.

The port 30a allows communication between the rod side oil chamber A and the piston side oil chamber B in the cylinder 1.

The valve 31 is arranged adjacent to the end surface of the piston body 30 on the rod-side oil chamber A side (left side in the figure), and closes the opening of the port 30a on the rod-side oil chamber A side.

Then, the valve 31 allows the hydraulic oil to flow from the piston side oil chamber B into the rod side oil chamber A through the port 30a by a lift movement that is a movement to the left in the drawing. At that time, a predetermined damping force is generated.

Note that a notch hole 31 is provided in the thick wall portion of the valve 31.
a is formed, so that even when the valve 31 is closed, the hydraulic oil from the rod side oil chamber A flows into the notch hole 31.
It is possible to flow to the piston side oil chamber B under the flow path resistance caused by a.

The valve stopper 32 regulates the amount of lift of the valve 31, and has a cutout hole 32a on its inner peripheral side.

Since the stay damper according to this embodiment is formed as described above, when the stay damper is extended and cut, it operates as follows.

First, when the external force that prevents the stay damper from extending is released, the piston part 3 slides in the cylinder 1 in the extension direction (to the left in the figure), and the piston rod 2 moves from the protruding and retracting end of the cylinder 1. The stay damper will be extended to the outside.

At this time, as the piston rod 2 withdraws, the hydraulic oil in the rod side oil chamber A flows into the piston side oil chamber B through the notch hole 31a of the valve 31 and the port 30a of the piston body 30.

Next, as the movement of the piston rod 2 progresses and the stay damper approaches its fully extended state, the tip of the collar 4 constituting the expanded diameter portion of the piston rod 2 is inserted into the through hole 8a on the inner peripheral side of the stop rubber 8. At the same time, it penetrates into the through hole 6a on the inner peripheral side of the stopper 6 adjacent to the stop rubber 8.

Therefore, a negative pressure chamber R is defined on one end side of the stopper 6, that is, on the left end side in the figure, by the stopper 6, the packing 5, and the piston rod 2.
The hydraulic oil in the stopper bar 8 is prevented from flowing through the through hole 8a on the inner circumferential side of the stopper 8. Therefore, the hydraulic oil in the negative pressure chamber R flows through the port 6b of the stopper 6 into the stopper bar 8. It will flow out to the side rod side oil chamber A side.

Then, as shown in FIG. 2, when the piston rod 2 moves further and the stay damper reaches the fully extended state, the valve stopper 32 of the piston portion 3 is adjacent to the stop rubber 8, and the stop rubber 8 is moved closer to the stopper 6. Since it is adjacent to the end surface 6c on the side of the piston-side oil chamber B, further extension of the stay damper is prevented.

End face 6c of the stopper 6 of the stopper lever 8
, the port 6b of the stopper 6 is closed, thereby preventing the hydraulic oil from flowing out from the negative pressure chamber R, and preventing the hydraulic oil from flowing into the negative pressure chamber R. The influx of people is also blocked.

Therefore, even if the stay damper is compressed from the fully extended state by the action of an external force such as wind and the piston rod 2 is stroked in the compression direction (rightward direction in the figure), the stopper 6 Since the port 6b is closed by the stop rubber 8,
Hydraulic oil is not allowed to flow into the negative pressure chamber R, and therefore a negative pressure, ie, a repulsive force that prevents the piston rod 2 from stroking in the compression direction, is generated within the negative pressure chamber R.

The repulsive force is then used as a holding force to maintain the extended state of the stay damper.

When the stay damper in the fully extended state is compressed with a force stronger than the negative pressure, the section where the expanded diameter portion of the piston rod 2 comes into sliding contact with the sealing O-ring 60 mounted on the inner circumferential side of the stopper 6 In this case, since the flow of hydraulic oil into the negative pressure chamber R is blocked, the negative pressure chamber R becomes a negative pressure, and the negative pressure at this time, that is, the repulsive force is caused by the collar 4.
This is generated by the pressure-receiving area that is set to have a cross-sectional area that is the outer diameter circle of , and therefore, the repulsive force increases only in this section.

When the collar 4 separates from the sealing O-ring 60, the negative pressure phenomenon in the negative pressure chamber R is released, the piston rod 2 is allowed to stroke in the compression direction, and the stay damper becomes compressible. Will be reinstated.

FIG. 3 shows stay dampers according to other embodiments of this invention, and the structure of each stay damper is basically the same as the structure of the stay damper of the embodiment shown in FIG. 1 described above. Therefore, the same reference numerals are used in the figures, and detailed explanation thereof will be omitted.

However, in the stay damper shown in FIG. 3, the packing 5 is formed in a simplified form without the metal 5a (see FIG. 1) on the surface adjacent to the cap 7.

Further, the stopper 6 is formed to be considerably shorter than the stopper 6 in the embodiment described above, and a sealing O-ring 60 disposed on the inner periphery of the stopper 6 is formed.
A back-up spring 61 parallel to the back-up spring 61 and an O-ring 62 disposed around the outer periphery of the back-up spring 61 are formed to have a considerably smaller diameter than those of the above-mentioned embodiment.

Therefore, according to the embodiment shown in FIG. 3, it is possible to increase the effective stroke of the piston rod 2 within the cylinder 1, and there is an advantage that the stay damper can be shortened when necessary.

FIG. 4 shows a stay damper according to still another embodiment of the invention, and the structure of each stay damper is also basically different from the structure of the stay damper of the embodiment shown in FIG. Therefore, the same reference numerals are given in the drawings, and detailed explanation thereof will be omitted.

However, in the case of the stay damper shown in FIG. 4, the stopper 6 includes a sealing O-ring 60 (see FIG. 3) on the inner circumferential side and a back-up spring 61 (see FIG. 3) parallel to this. omitting the arrangement, and instead, on the outer periphery of the collar 4 on the opposite side,
A sealing O-ring 40 and a back-up spring 41 parallel to the sealing O-ring 40 are provided.

Therefore, according to the embodiment shown in FIG. 4, the need for grooving the stopper 6 can be reduced, so there is an advantage that the strength of the stopper 6 can be maintained at a high level.

In each of the embodiments shown in FIGS. 1, 3, and 4 described above, the sealing O-rings 60, 40 disposed between the stopper 6 and the collar 4 are provided with the following: Backup spring 61, 41
Although the backup springs 61 and 41 are not necessarily provided, they may be omitted.

Furthermore, as shown in FIG. 5, the stopper lever 8 in each of the embodiments described above may have a reinforcing metal 8b disposed in the center thereof to increase its strength. The annular protrusion 8c may be formed on the surface or only on one end surface to improve sealing performance.

[Effect of idea]

As described above, according to this invention, it is possible to generate high negative pressure in the negative pressure chamber when the stay damper is extended, so it is easy to ensure sufficient holding force when the stay damper is extended. Of course, in doing so, it does not require high-performance and expensive sealing members or the use of multiple sealing members, so the stay damper can be manufactured under economically advantageous conditions, and its operability is also improved. It has many effects, such as preventing deterioration.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway front view showing a stay damper according to an embodiment of the invention, Fig. 2 is a partially cutaway front view showing the stay damper in its extended state, and Figs. 3 and 4 are respectively the same. FIG. 5 is a partially enlarged sectional view showing another embodiment of the stop rubber; FIG. 6 is a partially enlarged sectional view showing a stay damper according to another embodiment of the invention in an extended state; FIG. FIG. 2 is a partially cutaway front view showing the state in a partially broken state. Explanation of symbols: 1...Cylinder, 1a...Open end, 2...Piston rod, 3...Piston part,
6... Stopper, 6b... Port, 6c... End face, 8... Stop rubber, A... Rod side oil chamber, R... Negative pressure chamber.

Claims (1)

[Scope of utility model registration request] A piston rod is inserted into the cylinder so as to be retractable and retractable, and a piston part connected to the tip of the piston rod defines a rod-side oil chamber in the cylinder, and a stopper defines the rod-side oil chamber. In the stay damper having a negative pressure chamber formed therein, the stopper is provided with a port that communicates the negative pressure chamber and the rod side oil chamber, and
A stop rubber is adjacent to the end face of the stopper on the rod side oil chamber side so as to be able to be seated and removed, and the opening of the port on the rod side oil chamber side is formed so as to be closed when the stop rubber is adjacent to the stop rubber. A stay damper characterized by: