JP2005090520A - Seal member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To utilize a seal member that can be disposed to a prescribed position without causing useless stress concentration to secure prescribed seal functions permanently in such a way that it can be used for a gas spring, for example. <P>SOLUTION: The inner circumference of a base part 11 formed in a circular form having a hole having proper thickness for a rod body 2 to be inserted into a shaft core part is connected to the inner circumference of an inner circumferential side pressure contact part 12 formed in a cylindrical form at one end of the base part 11 under the structure of a curvature surface R1. Otherwise, the outer circumference of the base part 11 is connected to the outer circumference of the outer circumferential side pressure contact part 13 under the structure of the curvature surface R1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a seal member, and more particularly to an improvement of a seal member suitable for use in a gas spring.

  For example, a gas spring is mounted on a hatchback door in a vehicle, and the gas spring assists the opening operation of the hatchback door. There have been various proposals for this gas spring.

  As is the case with most types of gas springs, gas and oil in the cylinder body leaks out of the cylinder body, that is, gas and oil in the cylinder body penetrate the rod body through the shaft core. However, a seal member called U-packing is used to prevent leakage from the cylinder body through a gap that appears between the inner periphery of the bearing that seals the open end of the cylinder body and the outer periphery of the rod body. (For example, see Patent Document 1).

Therefore, in a gas spring having a sealing member called U-packing, when the sealing performance at other parts is ensured, unless the sealing member is deteriorated and the predetermined sealing function is lost. In addition, a predetermined pressure of gas and a predetermined amount of oil can be held for a long time, and a predetermined gas spring effect can be exhibited permanently.
JP 2003-14023 A (claims claim 1, paragraph 0002, paragraph 0006, paragraph 0008, paragraph 0022, paragraph 0028, paragraph 0030, FIG. 1, FIG. 2, FIG. 4 (A), (B))

  However, in the sealing member disclosed in Patent Document 1 described above, when being distributed to the predetermined position, a portion that will develop a settling time earlier than the other part in the same sealing member is generated. It may be pointed out that a predetermined sealing function over a long period cannot be guaranteed.

  That is, even in the above-described conventional seal member, the rod body is inserted through the shaft core portion with an appropriate thickness, as is the case with a seal member referred to as a U-packing of any kind. The inner peripheral side pressure contact portion and the outer peripheral side pressure contact portion, which are respectively cylindrical, are connected to one end of the annularly formed base portion having a hole. For example, the inner periphery of the base portion and the inner peripheral pressure contact portion From the cross-sectional view, the inner circumference is assumed that the so-called joint part of the two is continuous with an angle.

  On the other hand, as with the outer peripheral pressure contact portion, the inner peripheral pressure contact portion is in a state where an external force is not acting, that is, before being placed in the cylinder body, so as to ensure a so-called tightening margin, Therefore, at the time of distribution in the cylinder body, the inner circumferential side pressure contact portion is compressed to a so-called crushed state.

  At this time, in the above-described seal member, since the joint portion between the inner periphery of the base portion and the inner periphery of the inner peripheral pressure contact portion is continuous with an angle, the inner peripheral pressure contact portion is the outer periphery of the rod body. When it is pressed and crushed, the stress concentrates on the joint having this angle.

  And since the inner peripheral side pressure contact portion in the crushed state slides on the outer periphery of the rod body while being in pressure contact with the outer periphery of the rod body, there is a risk that deterioration starts from the portion where the stress is concentrated. In the case where deterioration is actually manifested, the sealing function of the sealing member as a whole is lowered and it becomes impossible to prevent leakage of gas and oil, and as a result, the gas spring effect cannot be expected to be exhibited for a long time in the gas spring. It will be.

  The present invention has been made in view of such a current situation, and the object of the present invention is to permanently prevent a predetermined sealing function from being caused by stress concentration during distribution to a predetermined position. For example, it is to provide a seal member that is optimal for expecting improvement in versatility in a gas spring.

  In order to achieve the above-described object, the structure of the sealing member according to the present invention is formed in an annular shape having an appropriate thickness and having a hole through which the rod body is inserted into the shaft core portion. In a sealing member formed by connecting an inner peripheral pressure contact portion and an outer peripheral pressure contact portion in a manner to be opposed to each other at one end of the base portion, the inner periphery of the base portion and the inner peripheral pressure contact portion It is assumed that the circumference is continuous under the curved surface structure, or the outer periphery of the base and the outer periphery of the outer peripheral pressure contact portion are continuous under the curved surface structure.

  According to claim 2, the upper and lower convergent surfaces forming the annular lip portion on the inner periphery of the inner peripheral pressure contact portion are curved surfaces, or the annular lip portion on the outer periphery of the outer peripheral pressure contact portion. It is assumed that the upper and lower converging surfaces forming the curved surface are curved surfaces.

  Therefore, in the first aspect of the invention, the joint portion between the inner periphery of the base portion and the inner periphery of the inner peripheral pressure contact portion is continuous with a curved surface having no angle. Even when the outer periphery of the base plate is pressed and crushed, stress is not concentrated on the joint, and the joint between the outer periphery of the base portion and the outer periphery of the outer peripheral pressure contact portion is continuous with a curved surface having no angle. Therefore, even if the outer peripheral pressure contact portion is pressed against the inner periphery of the cylinder body and is crushed, stress is not concentrated on the joint portion.

  In the invention of claim 2, the upper and lower converging surfaces forming the annular lip portion on the inner periphery of the inner peripheral pressure contact portion are curved surfaces, and the outer periphery of the outer peripheral pressure contact portion is annular Since the upper and lower convergent surfaces forming the lip portion are curved surfaces, stress is not concentrated on the roots from which the lip portion protrudes.

  As a result, according to the present invention, stress concentration is not incurred at the time of distribution to a predetermined position, and a predetermined sealing function can be permanently secured. For example, it is expected to improve versatility in a gas spring. It will be optimal.

  In the following, the present invention will be described based on the illustrated embodiment. The sealing member according to the present invention is embodied in a gas spring as shown in FIG. The rod body 2 is inserted into the cylinder body 1 so as to be able to protrude and retract, and a piston 3 slidably accommodated in the cylinder body 1 is connected to the tip of the rod body 2.

  In this gas spring, the piston 3 defines a piston-side gas chamber G1 and a rod-side gas chamber G2 in the cylinder body 1, and the piston-side gas chamber G1 and the rod-side gas chamber G2 are connected to the piston. 3 is communicated with a port 3a opened.

  In this gas spring, the opening end which is the lower end of the cylinder body 1 in the drawing is closed by the bearing member 4, and at this time, when the rod body 2 penetrates the shaft core portion of the bearing member 4. Therefore, the seal member is used to prevent oil and gas in the cylinder body 1 from leaking out of the cylinder body 1 through a gap that appears between the inner periphery of the bearing member 4 and the outer periphery of the rod body 2. 10 are distributed.

  In this gas spring, the retainer 5 is fixed to the inner periphery of the cylinder body 1 in the rod side gas chamber G2, and the rod body 2 protrudes from the cylinder body 1 with a large stroke. When the piston 3 comes into contact with the retainer 5 during the full extension operation, the piston 3 is prevented from coming into direct contact with the seal member 10, while the empty space A between the retainer 5 and the seal member 10 has oil, That is, lubricating oil is stored.

  In addition, although piston ring 31 is interposed in said piston 3, the technical idea in the sealing member 10 by this invention which may be generally called U packing is this piston ring so that it may mention later. 31 may be embodied.

  When the gas spring is formed as described above, the sealing member 10 according to the present invention is disposed at the upper end side in the drawing before being inserted into a predetermined position in the cylinder body 1 as shown in FIG. The leading end side becomes a so-called expanded state.

  Therefore, when the seal member 10 is disposed at a predetermined position in the cylinder body 1, for example, as shown in FIG. 1, an inner peripheral side pressure contact portion 12 described later is pressed against the outer periphery of the rod body 2. The outer peripheral side pressure contact portion 13 is pressed against the inner periphery B of the cylinder body 1, and gas and oil in the cylinder body 1 can be prevented from leaking out of the cylinder body 1.

  To explain a little, the seal member 10 basically has an appropriate thickness and has a base 11 formed in an annular shape having a hole (not shown) through which the rod body 2 is inserted in the shaft core portion. The inner peripheral pressure contact portion 12 and the outer peripheral pressure contact portion 13 are connected to each other so as to be opposed to each other by being formed in a cylindrical shape at one end as the upper end.

  Incidentally, the base 11 has an insert metal 14, and the mechanical strength of the insert metal 14 prevents the base 11 from being unnecessarily deformed. In the present invention, the base 11 is inserted metal. 14 is not a problem, and therefore the illustrated implementation base 11 may not have the insert metal 14.

  By the way, when the sealing member 10 according to the present invention is formed in the basic structure as described above, the inner periphery of the base portion 11 and the inner periphery of the inner peripheral pressure contact portion 12 are under the curved surface structure, that is, the curved surface R1. It is going to be continued in.

  Further, in the seal member 10, as shown in the figure, an annular lip portion 12 a is formed on the inner periphery of the inner peripheral pressure contact portion 12. It consists of a curved surface, that is, the above curved surface R1 which is an upper curved surface R2 and a lower curved surface.

  At this time, as shown in the figure, the curved surface R1, which is a continuous surface of the inner periphery of the base 11 and the inner periphery of the inner peripheral pressure contact portion 12, is simultaneously a curved surface which is a lower converging surface forming the lip portion 12a. However, considering the actual size of the seal member 10, it is difficult to form the curved surface R1 and the curved surface forming the lip portion 12a separately.

  Therefore, according to the present invention, the curved surface R1 which is a continuous surface between the inner periphery of the base portion 11 and the inner periphery of the inner peripheral pressure contact portion 12, and the lip portion 12a The curved surface, which is the lower converging surface that forms the surface, is configured separately, but this can be said in principle, as described above, from the fact that the sealing member 10 is formed. Then, it cannot be clearly separated, and it can be said that even if a single curved surface R1 is used, the establishment of the present invention is not hindered.

  FIG. 3 schematically shows a conventional seal member. In this seal member, the joint between the inner periphery of the base 11 and the inner periphery of the inner peripheral pressure contact portion 12 is shown. Has an angle C1, and the root of the annular lip portion 12a that is locked to the inner periphery of the inner peripheral pressure contact portion 12 has an angle C2.

  Therefore, in this conventional seal member, when the inner peripheral pressure contact portion 12 is pressed against the outer periphery of the rod body 2, the stress concentrates on the portion having the angles C1 and C2 and is larger than the other portions. As a result, premature deterioration appears as pointed out in the present invention.

  However, even if it is at the joint or root having this angle C1, C2, it can be said that it is continuous with a so-called round when viewed microscopically, so the so-called continuous part has a round. That is, it is not necessarily a new matter to be formed with a curved surface.

  However, the phenomenon of stress concentration at the joint as described above is not a phenomenon expressed when viewed microscopically, but a phenomenon expressed when viewed with the naked eye. In other words, the portion having the angles C1 and C2 in the conventional seal member is composed of the curved surfaces R1 and R2. Obviously the configuration is different.

  Therefore, in the sealing member 10 according to the present invention, the joint between the inner periphery of the base portion 11 and the inner periphery of the inner peripheral pressure contact portion 12 is continuous at a curved surface without an angle. Even when the side pressure contact portion 12 is pressed against the outer periphery of the rod body 2 and is crushed, stress is not concentrated on the joint portion.

  As a result, since stress concentration is not expressed, even if it is slidably contacted with the outer periphery of the rod body 2 in a state in which this stress concentration is not expressed, this portion does not deteriorate earlier than the other part, The sealing function of this is permanently expressed and can be sustained.

  By the way, although the above-mentioned place has taken as an example the case where the inner peripheral side pressure contact portion 12 in the seal member 10 is disposed in a state of sliding in contact with the outer periphery of the rod body 2, The piston ring 31 (see FIG. 1) can be used as a piston ring 31 (see FIG. 1) which is interposed on the outer periphery of the piston 3 (see FIG. 1) and is arranged in a state where the outer peripheral pressure contact portion 13 is in sliding contact with the inner periphery of the cylinder body become.

  That is, as shown in FIG. 4, in the piston ring 31 that is the seal member 10, the joint portion between the outer periphery of the base portion 11 and the outer periphery of the outer peripheral pressure contact portion 13 is continuous on the curved surface R <b> 1, and the outer peripheral pressure contact portion 13. In the drawing in which the annular lip portion 13a is formed on the outer periphery, the lower converging surface in the figure may be formed of the curved surface R2.

  Even when the seal member 10 is the piston ring 31, even if the outer peripheral pressure contact portion 13 is pressed against the inner periphery of the cylinder body 1 and is crushed, stress is concentrated on the joint portion. Disappear.

  Therefore, since stress concentration is not expressed, even if it is slidably contacted with the inner periphery of the cylinder body 1 in a state where this stress concentration is not expressed, this portion does not deteriorate earlier than the other parts, The predetermined sealing function can be permanently expressed and sustained.

It is a figure which shows the gas spring which has a sealing member by this invention. It is sectional drawing which shows one Embodiment of a sealing member. It is a figure which shows the conventional sealing member typically. It is a figure which shows embodiment which makes the seal member of this invention the piston ring interposed in the piston.

Explanation of symbols

2 Rod body 10 Seal member 11 Base 12 Inner peripheral side press contact part 12a, 13a Lip part 13 Outer peripheral side press contact part R1, R2 Curved surface

Claims (2)

An inner peripheral pressure contact portion and an outer peripheral pressure contact portion are formed in a cylindrical shape at one end of an annularly formed base portion having an appropriate thickness and having a hole through which the rod body is inserted into the shaft core portion. The base member and the inner periphery of the inner peripheral pressure contact portion are continuous under the curved surface structure, or the outer periphery of the base member and the outer periphery of the outer peripheral pressure contact portion are curved surface structures. A sealing member characterized by being continuous below The upper and lower convergent surfaces that form the annular lip portion on the inner circumference of the inner circumferential pressure contact portion are curved surfaces, or the upper and lower convergent surfaces that form the annular lip portion on the outer periphery of the outer circumferential side pressure contact portion are curved. The sealing member according to claim 1, wherein the sealing member is a surface.

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