JP2002286070A - Gas spring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas spring capable of preventing an oil film from breaking even if oscillation of fine amplitude occurs and preventing the wear of a main lip and a sublip and improving the durability and coaxial property of a the mainlip and the sublip. SOLUTION: A piston rod 3 is inserted movably into a cylinder 1 through a piston 2. The piston rod 3 is always urged to the elongation direction by a gas pressure. A seal 19 and a dust lip 23 are set in the vicinity of the end of the cylinder 1. The seal 19 is constituted of a seal body 20, a main lip 22 and an outer peripheral lip 21 provided at the inner end side of the seal body 20. In the gas spring in which the main lip 22 and the dust lip 23 are brought into slidable contact with the outer periphery of the piston rod 3 and the outer peripheral lip 21 is brough into contact with the inner periphery of the cylinder 1, the insert member is buried into the seal body 20 and the dust lip 23 adjacent to the main lip 22 is integrally provided at the outer end side of the seal body 20. The main lip 22 and the dust lip 23 are brought into slidable contact with the outer periphery of the piston rod 3 and a housing room 26 for oil or grease reservoir is formed between the main lip 22 and the dust lip 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle, which is interposed between a vehicle body and a back door, between a vehicle body and an engine hood, and in a window of a building to open and close the back door, the engine hood and the window. A gas spring suitable for enhancement.

[0002]

2. Description of the Related Art Generally, in a vehicle such as an automobile, for example, a gas spring constantly urged in a direction of expansion by gas pressure is interposed between a vehicle body and a back door to unlock the back door. When this happens, the back door opens slowly and automatically with the urging force of the gas spring.
As this gas spring, for example, the one shown in FIG. 3 has been developed.

[0003] This is because a piston rod 3 is movably inserted into a cylinder 1 via a piston 2 and the piston 2
Defines a gas chamber 4 and an oil chamber 5 in the cylinder 1, and the gas chamber 4 and the oil chamber 5 are connected via a port 6 formed in the piston 2. The piston 3 is guided in the axial direction by bearings 7 and retainers 8 provided in the vicinity of the end of the cylinder 1 and at an intermediate portion thereof.
To prevent contact.

In the vicinity of the end of the cylinder 1, a seal 9 is provided on the inner end of the bearing 7, and a dust lip 10 is provided on the outer end of the bearing 7.

[0005] One end of the cylinder 1 is connected via a bracket 11 to, for example, a back door of an automobile, and an end 12 of a piston rod 3 is connected to the vehicle body. When the back door is unlocked, the gas pressure in the gas chamber 4 is increased. With piston rod 3
Extends and automatically opens the back door. At this time, port 6
The piston rod 3 elongates slowly while being attenuated by the flow resistance of the gas flowing therethrough, so that no impact is applied to the back door.

The seal 9 prevents gas and oil in the cylinder 1 from leaking to the outside, and the dust lip 10 prevents dust from entering the cylinder from outside.

The seal 9 has a single lip structure, and as shown in FIGS. 3A and 3B, a seal body 13 made of rubber or the like.
, An outer peripheral lip 14 and a main lip 15 provided upright on the inner end side of the seal body 13, and an insert metal 16 embedded in the seal body 13.

The main lip 15 slides on the outer periphery of the piston rod 3 to prevent gas and oil from leaking to the outside from the outer periphery of the piston rod 3, and the outer lip 14 abuts on the inner periphery of the cylinder 1 and Gas and oil are also prevented from leaking from the inner circumference.

As a seal, for example, a double lip structure shown in FIG. 3C may be used. The seal 9a includes a seal body 13a, an outer lip 14a and a main lip 15a provided upright on the inner end side of the seal body 13a, a sub lip 15b provided on an inner circumference side of the seal body 13a, and a main lip 15a and the sub lip. 15b and an oil sump chamber 17 formed between the main lip 15a and the outer lip 14a.
a and the sub lip 15b are in sliding contact with the outer periphery of the piston rod 3 to prevent leakage of oil and gas inside each.

[0010]

Generally, when a gas spring is used for opening and closing a back door of an automobile,
Even when the back door is closed, the gas spring may vibrate at a small amplitude due to the deformation of the door, the play of the door hinge, the deformation of the door seat rubber material, and the like while the automobile is running.

The gas spring normally contains a high-pressure gas of about 10 MPa. Therefore, for example, the single lip type seal 9 is also applied with the high pressure, and the high pressure presses the main lip 15 to generate a high surface pressure on the contact surface with the piston rod 3. In this state, when the main lip 15 is vibrated with a small amplitude of, for example, about ± 1 mm, the main lip 15 scrapes out the oil film, and the piston rod 3 and the main lip 15
The oil slick intervening between the two is broken. If this state continues, the main lip 15 may be worn due to dry friction, and oil leakage or gas leakage may occur.

That is, as in the case of a general gas spring seal, the pressure applied to the main lip 15 of the seal 9 is high, so that the entire length of the main lip 15 contacts the piston rod 3. Therefore, the piston rod 3
Is about 2 to 4 mm. If the micro-amplitude vibration occurs as described above in this state, the oil is only supplied on the rear side of the main lip 15 distant from the oil, and the oil is not supplied. I do. In order to avoid this, for example, if the length of the main lip 15 is shortened, the surface pressure of the main lip 15 generated due to the gas pressure becomes excessive, and the main lip 15
In this case, the durability of the material such as rubber exceeds the allowable value, so that the abrasion occurs. Therefore, when a double lip structure as shown in FIG. 3C is used, an oil sump chamber 17 is provided between the main lip 15a and the sub lip 15b. Cutting is slightly prevented, but even in this case, the volume of the oil sump chamber 17 is small,
When the main lip 15a and the sub lip 15b are pressurized by the gas pressure, the oil in the oil sump chamber 17 is pushed out and the oil cannot be reinforced. appear. Similarly, the back side of the sub lip 15b also has a dry oil lubrication,
5b may also be worn.

Further, in the conventional gas spring, the seal 9 is used.
And the dust lip 10 are provided apart from each other, it is difficult to ensure concentricity with the piston rod 3.
Also, in order to ensure the sealing function, it is necessary to appropriately set the distribution of the surface pressure generated in each lip. However, if eccentricity occurs, it becomes uneven in the circumferential direction, and this cannot be ensured. Further, the dust lip 10 scrapes grease for reducing friction during movement, and the dust lip becomes dry lubricated,
Wear may occur.

Accordingly, an object of the present invention is to prevent the oil film from being broken even when vibration is applied due to minute amplitude, to prevent the main lip and the dust lip from being worn, and to attain the same durability as the main lip and the dust lip. An object of the present invention is to provide a gas spring capable of improving core properties.

[0015]

In order to achieve the above-mentioned object, the present invention provides a piston rod that is movably inserted into a cylinder via a piston, and the piston rod is always extended in a direction of extension by gas pressure. A seal and a dust lip are provided near the end of the cylinder, and the seal comprises a seal body, and a main lip and an outer lip provided on the inner end side of the seal body. In a gas spring in which the outer circumference lip is in contact with the inner circumference of the cylinder, the insert member is embedded in the seal body, and the dust lip adjacent to the main lip is mounted on the outer end side of the seal body. The main lip and the dust lip are slid in contact with the outer periphery of the piston rod. It is characterized in that the chamber of use was partitioned.

In this case, the base end of the sub lip is pressed against the outer end side of the insert member, and the front end is in sliding contact with the outer periphery of the piston rod.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a gas spring according to the present invention, and FIGS. 2 and 3 show a seal used for the gas spring.

The gas spring A is basically the same as the conventional one shown in FIG.

The gas spring A includes a cylinder 1, a piston rod 3 movably inserted into the cylinder 1 via a piston 2, a gas chamber 4 and an oil chamber 5 defined within the cylinder 1 via the piston 2. A port 6 formed in the piston 2 for connecting the gas chamber 4 to the oil chamber 5; a seal 19 and a bearing 1 provided near the end of the cylinder 1.
7 and the piston 2 provided in the cylinder 1
And a retainer 8 for preventing collision with the retainer 9.

Further, the end of the cylinder 1 is
And the outer end 12 of the piston rod 3 is connected to the vehicle body side.

The seal 19 mainly prevents leakage of gas and oil in the cylinder 1, and the bearing 17 cooperates with the piston 2 to guide the piston rod 3 in the axial direction.

The port 6 is used as a flow path when the gas passes and generates a damping force by the flow resistance at that time.

When the back door is unlocked, the gas chamber 4
The back pressure is automatically opened by the piston rod 3 being extended by the gas pressure of the above and the damping force is generated at the port 6. When the back door is closed, the back door is manually pushed in the closing direction against the gas pressure.

The above gas spring A is preferably used for opening / closing a back door of an automobile, but can also be used for opening / closing windows of a building or other similar opening / closing members.

In the above gas spring A, the present invention is an improvement of the seal 19 and the bearing 17.

The seal 19 includes a seal body 20 made of a material such as rubber, an insert metal 24 as an insert member embedded in the seal body 20, and a seal body 2.
A main lip 22 and an outer peripheral lip 21 which are inclined to the inner end side, which is a pressure side of 0, and stand up integrally; It is composed of

The seal 19 is formed by a known compression molding.
A material such as rubber is placed on the insert metal 24 and molded while being compressed in a mold. At this time, a part of the material flows on the inner peripheral side of the insert metal 24 and flows to the outer end side of the insert metal 24 to form the dust lip 23 in the mold. At this time, the base end 23a of the dust lip 23 is pressed against the outer end surface of the insert metal 24. Accordingly, the dust lip 23 is formed so as to face the main lip 22 with the insert metal 24 interposed therebetween, and an annular oil sump or grease accommodating chamber 26 is defined therebetween. The dust lip 23 is formed to have a relatively large thickness while being obliquely inclined from the base end to the front end.

The bearing 17 has an annular groove 27 at the upper portion on the inner peripheral side.
When the seal 19 is placed on the bearing 17, the dust lip 23 is received in the annular groove 27 so that the dust lip 23 does not interfere with the bearing 17.

In the seal 19, the lip tips of the main lip 22 and the dust lip 23 are in sliding contact with the outer peripheral surface of the piston rod 3 to prevent oil and gas from leaking from the outer periphery of the piston rod 3, and conversely, dust from the outside. Intrusion is prevented. The oil in the oil chamber 5 and the oil or grease in the chamber 26 are used as lubricating oil.

The outer peripheral lip 21 contacts the inner periphery of the cylinder 1 to prevent oil and gas from leaking from the inner periphery of the cylinder 1.

In this case, since the dust lip 23 is disposed at the base end on the outer end side of the insert metal 24, in other words, on the non-pressurization side where the gas pressure of the gas chamber 4 does not act, a high pressure is applied to the tip of the lip. Does not work. For this reason, even when vibrations due to minute amplitudes occur while the vehicle is running, the dust lip 23
Does not cut off the oil film on the outer periphery of the piston rod 3 and the oil or grease in the chamber 26 is always supplied as lubricating oil to prevent dry lubrication.

Further, a high surface pressure is generated on the contact surface between the main lip 22 and the piston rod 3 due to the gas pressure of the gas chamber 4. On the back side, there is a chamber 26 containing oil or grease, so that the oil film on the outer periphery of the piston rod 3 is not cut.
In addition, since the volume of the chamber 26 is increased at a position where the dust lip 23 is located away from the main lip 22, even if the main seal 19 is pressurized and compressed, oil or grease in the chamber 26 does not disappear. Thus, an oil film can always be formed.

[0034]

According to the present invention, the following effects can be obtained.

(1) According to the invention of each claim, the dust lip is provided on the outer end side of the seal body, in other words, on the outer end side of the insert member where the gas pressure of the gas chamber does not act. Does not have a high surface pressure between the piston rod. For this reason, even when the dust lip is vibrated while the automobile is running and does not vibrate, the oil film on the outer periphery of the piston rod will not be cut, so that dry lubrication will not occur, and the dust lip will be prevented from being worn and durable. Performance and prevent leakage of oil and gas in the cylinder.

(2) Similarly, since the dust lip is provided on the outer end side of the seal main body, the distance between the main lip and the main lip can be increased, thereby increasing the volume of the chamber between the main lip and the dust lip. Therefore, even if the gas pressure acts on the lip body and the main lip to compress the lip body and the main lip, the entire amount of oil or grease in the chamber is not pushed out to the oil chamber side. For this reason, oil always remains on the back side of the main lip, and even if the main lip is vibrated by a minute amplitude under high surface pressure, the oil in the oil sump is supplied to the back side of the main lip. It does not cut the oil film. Therefore, the main lip is not dry-lubricated, so that abrasion is prevented, durability is improved, and leakage of oil and gas is prevented.

(3) Since the main lip and the dust lip are integrally formed, the concentricity of both can be accurately secured, the surface pressure distribution of both can be appropriately set, and the number of parts can be reduced.
Processability, assemblability, and economy are also improved.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view of a gas spring according to one embodiment of the present invention.

FIG. 2 is a partially enlarged sectional view of a seal.

FIG. 3A is a vertical sectional front view of a conventional gas spring. (B) (C) It is a partial expanded sectional view of a seal.

[Explanation of symbols]

 Reference Signs List 1 cylinder 2 piston 3 piston rod 19 seal 20 seal body 21 outer peripheral lip 22 main lip 23 dust lip 24 insert metal as insert member 26 chamber

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Etsuro Nakata 2-4-1 Hamamatsucho, Minato-ku, Tokyo World Trade Center Building Kayaba Industry Co., Ltd. F-term (reference) 3J069 AA01 CC22 DD07

Claims (2)

[Claims] 1. A piston rod is movably inserted into a cylinder via a piston, the piston rod is constantly urged in a direction of extension by gas pressure, and a seal and a dust lip are provided near an end of the cylinder. The seal consists of a seal body, a main lip and an outer lip provided on the inner end side of the seal body, and the main lip and the dust lip are slid on the outer circumference of the piston rod, and the outer lip is brought into contact with the inner circumference of the cylinder. In the gas spring, the insert member is embedded in the seal body, and a dust lip adjacent to the main lip is integrally provided on the outer end side of the seal body,
A gas spring in which a main lip and a dust lip are slidably contacted with the outer periphery of a piston rod and a chamber for oil sump or grease is defined between the main lip and the dust lip. 2. The gas spring according to claim 1, wherein a proximal end of the dust lip is pressed against an outer end of the insert member, and a distal end thereof is in sliding contact with the outer periphery of the piston rod.