JPH04254023A - Gas damper stay - Google Patents

Abstract

PURPOSE:To obtain a gas damper stay compact and simple in structure provided with temperature self-compensating function so as to maintain the constant operating feeling regardless of temperature change. CONSTITUTION:A piston rod 28 is formed to be movable in the axial direction of a cylinder 24. High pressure gas 40 and liquid 42 are filled in a cylinder 24, and the piston rod 28 is energized in the extended direction by pressure difference applied to the face corresponding to the provided part of the piston rod 28. Nitrogen (N2) is selected as the high pressure gas 40, and n-octane is selected as the liquid. The solubility of the high pressure gas 40 into the liquid 42 is increased with temperature rise. Accordingly, even if the high pressure gas 40 is expanded due to the temperature rise of the high pressure gas 4, the solubility of the high pressure gas 40 into the liquid 42 is increased, so that the number-of-molecules of the high pressure gas 40 is reduced to prevent pressure rise in the cylinder 24. An operating feeling regarding the opening/ closing operation of a back door 14, opening speed, and the like can be thereby maintained constant regardless of temperature change.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas damper stay that biases an opening/closing body toward a main body in an opening direction.

0002

[Prior Art] A gas damper stay has been proposed in which high-pressure gas or liquid (oil, etc.) is sealed in a cylinder and the piston rod is made to protrude from the cylinder by utilizing the pressure in the cylinder to energize a vehicle back door, etc. There is.

As shown in FIG. 5, this gas damper stay 60 is composed of a cylinder 62 and a piston rod 64. Inside the gas damper stay 60,
A small amount of hydraulic oil 66 that generates damping force and high pressure gas 68
(Nitrogen gas) is sealed. The pressure of this high pressure gas 68 urges the piston rod 64 in the direction of extension with respect to the cylinder 62.

Gas damper stay 60 having such a configuration
By interposing it between the main body of the vehicle and the back door or engine hood, the operating force for opening the back door or engine hood can be reduced and the opened state can be maintained.

By the way, in the gas damper stay 60, when the temperature of the high pressure gas 68 in the cylinder 62 changes, the internal gas pressure changes according to Boyle-Shall's law, and the biasing force changes. This change affects the opening/closing force of the back door or engine hood, resulting in a large change in operational feel between summer and winter, resulting in poor operability.

FIG. 6 shows the change characteristics of the urging force of the piston rod 64, that is, the repulsion force, and the stroke due to temperature changes when the conventional gas damper stay is used. As shown in Figure 6, the repulsive force decreases at low temperatures (-30 degrees) compared to normal temperature of +20 degrees, and increases at high temperatures (+70 degrees). You can see that the feeling changes.

In order to solve this problem, it has been considered to provide an auxiliary stay in addition to the gas damper stay 60, and compensate for the temperature change with the auxiliary stay (see Japanese Patent Laid-Open No. 142178/1983). . According to this, the operating feeling can be maintained substantially constant regardless of temperature changes.

[0008]

However, the conventional structure described above requires a pair of stays, the ordinary gas damper stay 60 and an auxiliary stay, which increases the number of parts and complicates the structure. Moreover, the assembly workability for attaching the pair of stays is poor.

Here, as a means to maintain an almost constant operating feeling using a single gas damper stay, the gas damper stay is made large, the volume of gas sealed in its cylinder is increased, and the broken line in FIG. Although it is conceivable to use the gas damper in a range where changes in the pressure of the characteristic shown by are moderated (range shown by arrow A in FIG. 3), the gas damper stay becomes large, which is not preferable.

In view of the above facts, the present invention has a self-temperature compensation function, can maintain a constant operating feeling regardless of temperature changes, is small and lightweight, has a simple structure, and improves assembly workability. The purpose is to obtain a gas damper stay that can.

[0011]

[Means for Solving the Problems] A gas damper stay according to the present invention is a gas damper stay that biases an opening/closing member in the opening direction with respect to a main body, and is attached to either the main body or the opening/closing member and has a high-pressure gas damper stay. and a cylinder filled with a liquid, and a piston equipped with a rod that is attached to the other side of the main body or the opening/closing body and is moved in the axial direction by the difference between the pressure caused by the high pressure gas and liquid and the atmospheric pressure, It is characterized in that the high pressure gas and liquid are combined so that the solubility of the high pressure gas in the liquid increases as the temperature rises.

0012

According to the present invention, the combination of high-pressure gas and liquid sealed in the cylinder is selected so that the amount of high-pressure gas dissolved in the liquid increases as the temperature rises.

Examples of combinations of high pressure gas (gas) and liquid (solvent) to provide the above properties will be shown below.

[0014]

[Table 1]

By selecting high-pressure gas and liquid in combinations corresponding to the circles in the table above, it is possible to prevent the high-pressure gas from expanding due to high temperature and increasing the biasing force. Therefore, the operating feeling can be maintained constant regardless of temperature changes. Furthermore, there is no need to provide a separate rod for temperature compensation, and the structure is simplified. By simplifying the structure, the workability of assembling the main body and the opening/closing body is improved.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 shows the rear part of a vehicle 12 to which a gas damper stay 10 according to the present invention is applied.

The back door 14, which is an opening and closing body, is pivotally supported by a roof portion 18 of a vehicle body 16, which is a main body, via a hinge 20, and can be opened and closed about an axis L.

Brackets 22 are attached to the vehicle body 16 in correspondence with both sides of the back door 14. This bracket 22 includes a gas damper stay 10 according to the present invention.
A cylinder 24 is attached. A ball joint portion 26 is interposed between the cylinder 24 and the bracket 22. A piston rod 28 projects from the tip of the cylinder 24.

As shown in FIG. 1, a seal packing 30 and a bearing 32 are provided on the protruding portion of the piston rod 28 of the cylinder 24.
is penetrated. The seal packing 30 seals the inside of the cylinder 24, and the bearing 32 restricts movement of the piston rod 28 in directions other than the axial direction.

As shown in FIG. 1, the piston rod 28 is attached to a piston 34 housed within the cylinder 24, and is movable in the axial direction of the cylinder 24.

The distal end of the piston rod 28 in the extending direction is attached to a bracket 38 attached to the back door 14 via a ball joint 36.

A high pressure gas 40 and a liquid 42 are sealed inside the cylinder 24. Further, the piston 34 is provided with an orifice 44. The chambers 46 and 48 in the cylinder 24, which are divided into two by the piston 34, have a constant pressure P because the orifice 44 is provided. Here, a piston rod 28 is attached to the chamber 46 side, and the cylinder 24 is attached to both end surfaces of the piston 34 excluding the piston rod 28.
Since a certain internal pressure is applied, the pressing force on the piston 34 due to this pressure is canceled out.

However, on the side of the chamber 46, atmospheric pressure P0 acts on the cross-sectional area of the piston rod 28 (symbol S in FIG. A pressure P is applied. Here, since the pressure P inside the cylinder 24 is higher than the atmospheric pressure P0, the piston 34 is pushed toward the chamber 46,
The piston rod 28 is urged in the extending direction.

By the way, the operation feeling in the opening direction of the back door 14 is determined by the relational expression (PV=nRT) representing the well-known Boyle Schall's law, as the temperature rises.
When the pressure inside the cylinder 24 increases, the piston rod 2
8 increases, the rotational force of the back door 14 in the opening direction increases, and the rotation speed increases.

Furthermore, when the temperature decreases, the pressure inside the cylinder 24 decreases, and the pressure that urges the piston rod 28 decreases, reducing the rotational force of the back door 14 in the opening direction and slowing the rotation speed. .

Therefore, in this embodiment, the above PV=nR
Focusing on the relational expression of T, as the temperature T rises, the number of molecules n decreases, PV=constant, and in order to maintain the pressure in the cylinder 24 constant, the high pressure gas 40 in the cylinder 24 is
N2 (nitrogen) is applied to the liquid 42, and n-octane is applied to the liquid 42. This combination is such that the amount of high-pressure gas 40 dissolved into liquid 42 increases as the temperature rises. For this reason, high pressure gas 4
The temperature of zero increases, it expands, and the pressure increases.
This is prevented by dissolving the high pressure gas into the liquid 42 and reducing the number n of molecules of the high pressure gas 40.

The operation of this embodiment will be explained below. When the back door 14 is opened from a closed state, the lock of the back door 14 to the vehicle body 16 is released. By this unlocking, the back door 14 is opened to the cylinder 2.
As the piston rod 28, which has a biasing force due to the difference between the pressure inside the piston rod 4 and the atmospheric pressure, begins to extend, the axis L moves in the opening direction.
It is rotated around.

Furthermore, when closing the back door 14,
The back door 14 is pressed in the closing direction with a force greater than the biasing force. As a result, the piston rod 28 is pushed back into the cylinder 24, and the back door 14 can be closed.

By the way, a high-pressure gas 40 is sealed in the cylinder 24, and due to the nature of the gas, it may expand due to a rise in temperature and change the biasing force. Changes in the biasing force affect the operation feeling of the backdoor 14, such as the opening/closing force and opening speed.

However, in this embodiment, the high-pressure gas 40 and liquid 42 to be sealed are selected in order to maintain a constant operational feeling regardless of this temperature change.

In this embodiment, N2 (nitrogen) is selected as the high pressure gas 40 in the cylinder 24, and n-octane is selected as the liquid 42. This selection is based on Table 1 shown in the Operation of the Invention section.

With this combination, the solubility of the high pressure gas 40 in the liquid 42 increases as the temperature rises. Therefore, for example, even if the temperature T of the high-pressure gas 40 becomes high and the high-pressure gas expands, the solubility in the liquid 42 increases, so some of the high-pressure gas 40 dissolves in the liquid 42 and the high-pressure gas 40 The number of molecules n decreases, PV=constant, and an increase in pressure within the cylinder 24 can be prevented. As a result, as shown in FIG. 3, the biasing force of the gas damper stay 10 against the backdoor 14 can be maintained almost constant regardless of temperature changes (-30 degrees, plus 20 degrees, and plus 70 degrees). .

Furthermore, as shown by the solid line in FIG. 4, even if the volume is small, there is little pressure change, so the range of use (range shown by arrow B in FIG. 4) can be the small volume part, and the gas damper The stay 10 itself can be made smaller and lighter.

Furthermore, since it has a temperature compensation function,
A separate auxiliary stay for temperature compensation is not required, simplifying the structure. Therefore, assembly workability can also be improved.

In this example, from Table 1, high pressure gas 4
N2 (nitrogen) is selected as 0, and as liquid 42,
Although n-octane was selected, similar effects can be obtained by using the combinations indicated by the circles in Table 1.

Furthermore, although the high-pressure gas 40 and liquid 42 shown in Table 1 are currently applicable to the gas damper stay 10, the solubility of the high-pressure gas 40 in the liquid 42 increases as the temperature rises. Substances other than those shown in Table 1 can also be used in combination.

Further, in this embodiment, the back door 14 of the vehicle 10 is used as the opening/closing body to which the gas damper stay 10 is attached.
However, it can also be applied to other opening/closing bodies such as engine hoods and side doors.

[0038]

[Effects of the Invention] As explained above, the gas damper stay according to the present invention has a self-temperature compensation function and can maintain a constant operating feeling regardless of temperature changes.
It has the excellent effect of being small and lightweight, having a simple structure, and improving assembly workability.

[Brief explanation of the drawing]

FIG. 1 is an axial cross-sectional view of a gas damper stay according to the present embodiment.

FIG. 2 is a perspective view showing the rear part of a vehicle to which the gas damper stay of the present invention is applied.

FIG. 3 is a stroke-repulsion force characteristic diagram of the gas damper stay according to the present embodiment.

FIG. 4 is a characteristic diagram showing the relationship between gas volume and pressure inside the cylinder.

FIG. 5 is a sectional view showing the internal structure of a conventional gas damper stay.

FIG. 6 is a stroke-repulsion characteristic diagram of a conventional gas damper stay.

[Explanation of symbols]

10 Gas damper stay 14 Back door (opening/closing body) 16 Vehicle body (main body) 24 Cylinder 28 Piston rod (rod) 34 Piston 40 High pressure gas 42 Liquid

Claims (1)

[Claims] 1. A gas damper stay that urges an opening/closing body relative to a main body in an opening direction, the stay comprising: a cylinder attached to one of the main body or the opening/closing body and filled with high-pressure gas and liquid; a piston equipped with a rod attached to the other side of the body and moved in the axial direction by the pressure of the high pressure gas and liquid, so that the solubility of the high pressure gas in the liquid increases as the temperature rises. A gas damper stay characterized by combining the high pressure gas and liquid.