JPH07238967A - Stay damper - Google Patents

Abstract

PURPOSE:To make the volume of a gas chamber alterable with a yet simpler structure by securing a stopper, regulating any elongative displacement of more than the specified value, to the specified position of a piston rod in the inner part of a cylinder. CONSTITUTION:A small hole 9A is formed in a piston 9 as a passage for interconnecting both gas chambers A1 and A2. In addition, a sliding clearance lying between this piston 9 and a cylinder 2 will function as a similar passage. Likewise a check valve 8 being opened by dint of high pressure at the side of the gas chamber A2 but closed by that of the side of the gas chamber A1 respectively is installed in an opening at the side of the gas chamber A1 of the small hole 9A. In this case, a valve opening position of this check valve 8 is regulated by a valve stop 23 clamped to a piston rod 1. In addition, a stopper 25 is secured tight to the piston rod 1 by means of caulking, and this stopper 25 comes into contact with a rebound stopper 6, thereby regulating any elongation of more than specified value of the piston rod 1. Therefore the piston rod 1 different in length is used, and a mounting position of the stopper 25 is altered according to this length, whereby different spring load is thus securable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a gas damping type stay damper for assisting opening and closing of a swing door of an automobile or the like.

[0002]

2. Description of the Related Art A gas damping type stay damper for supporting a swing door of an automobile or the like defines gas chambers on both sides of a piston housed in a cylinder, and flows between the gas chambers as the piston slides. A damping force against expansion and contraction is generated by the communication resistance of the gas, and the piston is biased in the extension direction by the pressure of the compressed gas.

In such a stay damper, the required spring load also differs depending on the weight and supporting angle of the target swing door. However, if the overall size and the design of the component parts are changed to meet these requirements, the manufacturing cost of the stay damper increases, so it is desirable to use different common parts while using different spring loads.

Therefore, for example, Japanese Utility Model Publication No. 4-22112 proposes a stay damper in which a piston rod penetrates a piston and the penetrating end projects into a gas chamber in which compressed gas is sealed. A thread is cut on the outer periphery of the penetrating portion of the piston rod, and the piston is fixed to the piston rod by tightening a nut screwed to the threaded portion. Therefore, if piston rods having different thread lengths are used, the volume of the gas chamber at the same expansion / contraction position changes, and different spring loads can be set.

[0005]

In the case of this stay damper, it is necessary to prepare a piston rod in which the length of the threaded portion is changed depending on the required spring load condition, but it is troublesome to process the piston rod having a long threaded portion. There was a problem. Further, if the threaded portion is long, the number of man-hours for tightening the nut inevitably increases.
Further, since the screw portion largely projects from the nut, it is impossible to prevent the nut from loosening by caulking the tip of the screw portion after tightening the nut, and it is necessary to prevent the nut from loosening by another method.

From the above, it cannot be said that the cost reduction effect of this stay damper is sufficiently high.

The present invention has been made to solve the above problems, and an object of the present invention is to make it possible to change the volume of a gas chamber with a simpler structure.

[0008]

According to a first aspect of the present invention, a piston is slidably accommodated in a cylinder, and a piston rod connected to the piston is slidably projected in the axial direction from the cylinder. While defining a gas chamber on both sides of the internal piston, in a stay damper in which the piston is provided with a passage that connects the gas chambers on both sides, a stopper that restricts extension displacement above a certain level is provided at a predetermined position of the piston rod inside the cylinder. It is fixed.

According to the second aspect of the invention, the distance between the piston and the stopper is set equal to the difference in the length of the piston rod.

According to a third aspect of the present invention, a piston is slidably accommodated in a cylinder, and a piston rod connected to the piston is slidably protruded from the cylinder in an axial direction. While defining the gas chamber,
In a stay damper in which a small hole that connects the gas chambers on both sides to the piston is provided, a stopper that restricts extension displacement above a certain level and a volume reducing member that reduces the volume of the gas chamber are provided at predetermined positions of the piston rod inside the cylinder. It is fixed.

According to a fourth aspect of the invention, the volume reducing member is fixed to the piston rod integrally with the piston.

According to a fifth aspect of the present invention, the piston is slidably accommodated in the cylinder, and the piston rod connected to the piston is slidably protruded from the cylinder in the axial direction. A gas chamber is defined, and at least two passages that connect the gas chambers on both sides to the piston are provided. The passage is closed by the high pressure of the gas chamber on the piston rod side, and the passage is closed for the high pressure of the other gas chamber. A stay damper provided with an opening check valve in an opening facing the gas chamber on the piston rod side of at least one of the passages,
At the predetermined position of the piston rod inside the cylinder, a stopper that restricts extensional displacement above a certain level and a volume reducing member that reduces the volume of the gas chamber are fixed, and the valve opening operation of the check valve is performed on this volume reducing member. A valve stopper that regulates at a predetermined position is integrally provided.

[0013]

According to the first aspect of the invention, by changing the length of the piston rod, the volume of the gas chamber at the same expansion / contraction position of the piston rod changes, and different spring loads can be obtained. Further, the stopper restricts the extension movement of the piston rod more than necessary.

According to the second aspect of the present invention, the distance between the piston and the stopper is set equal to the difference in the length of the piston rod. It will be constant.

In the third aspect of the invention, the volume reducing member reduces the volume of the gas chamber and enables a greater change in the spring load.

According to the fourth aspect of the present invention, by fixing the volume reducing member integrally with the piston to the piston rod, the volume reducing member can be fixed without a dedicated fixing member or a fixing operation. .

According to the invention described in claim 5, the number of parts constituting the stay damper is reduced by integrally providing the volume reducing member with the valve stopper, and the structural stability of each member is secured by the integration. .

[0018]

1 to 4 show an embodiment of the present invention.

In the stay damper shown in FIG. 1, a piston 9 is slidably accommodated inside the cylinder 2, and gas chambers A ₁ and A ₂ are defined on both sides. The piston 9 is normally urged in the extension direction of the piston rod 1 by the pressure of the compressed gas filled in the gas chambers A ₁ and A ₂ . A predetermined amount of oil 15 is enclosed in the gas chambers A ₁ and A ₂ .

3 is a dust seal, 4 is a rod guide, 5
Is a packing, 6 is a rebound stopper having a fail-safe function, 11 is a lower cap for sealing the gas chamber A ₂ , and 12 is a plug provided at the inlet of the gas and oil 15.

A small hole 9A is formed in the piston 9 as a passage for connecting the gas chambers A ₁ and A ₂ . Also, the piston 9
The sliding gap between the cylinder 2 and the cylinder 2 functions as a similar passage to allow the gas to flow between the gas chambers A ₁ and A ₂ .

A check valve 8 is provided at the opening of the small hole 9A on the gas chamber A ₁ side and is opened by the high pressure on the gas chamber A ₂ side and closed by the high pressure on the gas chamber A ₁ side. The valve opening position of the check valve 8 is regulated by a valve stopper 23 fixed to the piston rod 1.

As a result, when the piston 9 contracts, gas flows through the small hole 9A and the sliding gap between the piston 9 and the cylinder 2, respectively, but when the piston 9 extends, only the sliding gap exists. The gas circulates and generates a larger damping force. It should be noted that the piston 9 and the valve stopper 23 are integrally formed by a nut 10 that is screwed into a threaded portion formed at the tip of the piston rod 1.
Fixed to.

Further, the piston rod 1 has a stopper 25.
It is fixed by caulking.

This stopper 25 is a rebound stopper 6
It has a function of restricting the extension of the piston rod 1 above a certain level by abutting against the.

Next, the operation will be described.

In this stay damper, different spring loads are realized by using piston rods of different lengths and changing the mounting position of the stopper 25 according to the lengths.

FIG. 2C shows the length L of the piston rod 1 of the stay damper shown in FIG. 1 and the fixing position of the stopper 25.

On the other hand, the length L ₁ of the piston rod 1A of the stay damper shown in FIG. 2A is equal to the length from the base end of the piston rod 1 to the stopper 25 in FIG. The length L ₂ of the piston rod 1B of the stay damper shown in (b) is equal to the length L ₁ of the piston rod 1A of FIG. 2 (a) plus the length of the stopper 25.

The stopper 25 is not attached to the piston rod 1A, and the stopper 25 is attached to the piston rod 1B at a position in contact with the piston 9.

As a result, any extension of any piston rod is restricted by the rebound stopper 6 at the same position. Therefore, when the stay damper supports the swing door, the open door position is the same regardless of which stay damper is used.

The most contracted position of the piston 9 is shown in FIGS.
Although different for each stay damper in (c), the most contracted position of the stay damper when supporting the swing door is constant because it is the closed position of the swing door. That is, all the stay dampers operate in the same stroke range when supporting the swing door.

On the other hand, the position of the piston 9 when the piston rod extends to the same position is different for each stay damper, and in the stay damper of FIG.
Compared with the stay damper of (a), the total gas volume of the gases A ₁ and A ₂ is excessively compressed by the volume of the stopper 25, and in FIG. The volume of the piston rod 1 is further compressed. Therefore, the stay dampers of FIGS. 2A to 2C have different spring loads.

Therefore, by using the piston rod and the stopper 25 having different lengths, different spring loads can be realized while the other members remain the same, which makes it easy to cope with swing doors having different weights, for example. Can be done. Since the stopper 25 is fixed by caulking, it can be easily attached. It should be noted that the piston rod simply changes its length, and it is not necessary to change the processing length of the threaded portion or the like.

FIG. 3 shows a second embodiment of the present invention. Here, the collar 26 is used as the volume reducing member in order to make it possible to change the spring load to a greater extent that cannot be dealt with only by changing the length of the piston rod. Color 26
Is fixed to the outer circumference of the piston rod 1 by caulking or press fitting. As a result, the enclosed gas is further compressed by the volume of the collar 26, which is effective, for example, when the length of the piston rod is increased to the limit but the spring load is still insufficient. Further, since the collar 26 is fixed by caulking or press fitting, the fixing work is easy. In addition, the fixing by press fitting is done by the collar 26 on the piston rod 1.
Since the positioning and fixing can be performed at the same time as the insertion, the manufacturing cost can be further reduced as compared with the fixing by caulking.

FIG. 4 shows still another embodiment relating to the volume reducing member, in which the collar 26 is formed in a cylindrical shape with a bottom, the piston rod 1 is penetrated together with the piston 9, and the nut 10 is attached to the piston rod 1. Fix it together. The collar 26 also serves as the valve stopper 23 shown in FIG. With such a configuration, the number of parts is reduced, and the structural stability is increased by the integration, and it is possible to suppress rattling of the collar 26 and generation of a hitting sound due to the operation.

[0037]

As described above, according to the first aspect of the present invention, by changing the length of the piston rod, the spring load can be easily changed while the unnecessary extension operation is restricted by the stopper. You can

Therefore, it is possible to easily and inexpensively cope with the required difference in spring load.

According to the second aspect of the invention, the most extended position of the stay damper can be made to coincide with each other regardless of the length of the piston rod by the mounting position of the stopper.

According to the third aspect of the invention, since the volume reducing member enables the spring load to be changed more significantly,
The spring load range of the stay damper is increased.

According to the fourth aspect of the invention, since the volume reducing member is fixed to the piston rod integrally with the piston, the volume reducing member can be easily fixed to the piston rod without increasing the number of parts for fixing. .

According to the fifth aspect of the present invention, since the valve stopper is formed integrally with the volume reducing member, the number of parts constituting the stay damper is reduced, and the structural stability is improved by the integration.

Therefore, according to the present invention, the spring load of the stay damper can be changed inexpensively and easily.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a stay damper showing an embodiment of the present invention.

FIG. 2 is a schematic vertical sectional view of a stay damper using piston rods having different lengths.

FIG. 3 is a vertical cross-sectional view of a main portion of a stay damper showing another embodiment of the present invention.

FIG. 4 is a longitudinal sectional view of a main part of a stay damper showing still another embodiment.

[Explanation of symbols]

1 Piston Rod 2 Cylinder 8 Check Valve 9 Piston 9A Small Hole 23 Valve Stopper 25 Stopper 26 Collar A ₁ , A ₂ Gas Chamber

Claims (5)

[Claims] 1. A piston is slidably housed in a cylinder, and a piston rod connected to the piston is slidably projected in the axial direction from the cylinder to define gas chambers on both sides of the piston inside the cylinder. A stay damper having a small hole for communicating a gas chamber on both sides with a piston, wherein a stopper for restricting extension displacement above a certain level is fixed to a predetermined position of a piston rod inside a cylinder. 2. The stay damper according to claim 1, wherein the distance between the piston and the stopper is set equal to the difference in the length of the piston rod. 3. A piston is slidably accommodated in a cylinder, and a piston rod coupled to the piston is slidably protruded from the cylinder in an axial direction so as to define a gas chamber on both sides of the piston inside the cylinder. In a stay damper in which a small hole that connects the gas chambers on both sides to the piston is provided, a stopper that restricts extension displacement above a certain level at a predetermined position of the piston rod inside the cylinder, and a volume reducing member that reduces the volume of the gas chamber, A stay damper characterized by fixing. 4. The stay damper according to claim 3, wherein the volume reducing member is fixed to the piston rod integrally with the piston. 5. A piston is slidably accommodated in a cylinder, a piston rod connected to the piston is slidably projected in the axial direction from the cylinder, and a gas chamber is defined on both sides of the piston inside the cylinder. The piston is provided with at least two passages communicating with the gas chambers on both sides, and a check valve for closing the passage by the high pressure of the gas chamber on the piston rod side and opening the passage for the high pressure of the other gas chamber is provided in the passage. In a stay damper provided in an opening facing at least one piston rod-side gas chamber, a stopper for restricting extension displacement at a predetermined position or more at a predetermined position of the piston rod inside the cylinder, and a volume reduction for reducing the volume of the gas chamber The member is fixed, and a valve stopper for restricting the opening operation of the check valve at a predetermined position is integrally provided with the volume reducing member. Stay damper to be.