CN-116097023-B - Sealing structure and method for assembling sealing structure

Abstract

The invention provides a sealing structure capable of exerting stable sealing performance for a long time and an assembling method of the sealing structure. An annular fitting groove (310) for fitting a resin gasket (100) is provided in a mounting member (300), and an annular protrusion (311) is provided at the bottom of the fitting groove (310), the annular protrusion (311) having a tapered surface (311 a) that expands in diameter from a pressurizing side (H) toward a counter-pressurizing side (L), and a tapered surface (311 b) that contracts in diameter from the pressurizing side (H) toward the counter-pressurizing side (L), the tip of the annular protrusion (311) being disposed so as to be offset toward the pressurizing side (H) from the center in the groove width direction in the fitting groove (310).

Inventors

• NAKAYAMA KENICHI

Assignees

• NOK株式会社

Dates

Publication Date

20260512

Application Date

20211006

Priority Date

20201120

Claims (5)

1. 1. A sealing structure, comprising: a mounted member having a mounting hole; A mounting member mounted to the mounting hole, and A cylindrical resin gasket for sealing a gap between a pressurizing side, which is pressurized by a pressure of a fluid to be sealed, and a counter pressurizing side, which is opposite to the pressurizing side, by an annular gap provided between the mounting hole and the mounting member, The sealing structure is characterized in that, The mounting member is provided with an annular fitting groove for fitting the resin gasket, and An annular projection having a first tapered surface that expands in diameter from the pressurizing side toward the counter-pressurizing side and a second tapered surface that reduces in diameter from the pressurizing side toward the counter-pressurizing side is provided at the bottom of the fitting groove, the tip of the annular projection being disposed so as to be offset toward the pressurizing side from the center in the groove width direction in the fitting groove, The taper angle of the first taper surface is greater than the taper angle of the second taper surface, The mounting member of the first tapered surface has a length in an axial direction shorter than a length in the axial direction of the second tapered surface.
2. 2. The seal structure of claim 1, wherein, The resin gasket is mounted in the mounting groove at a position biased toward the pressing side, and a gap is provided between the side wall surface of the mounting groove on the opposite pressing side and the resin gasket in a state where no pressure is applied from the pressing side.
3. 3. A sealing structure according to claim 1 or 2, wherein, The side wall surface on the pressing side in the fitting groove is formed of a surface perpendicular to the central axis of the resin gasket.
4. 4. A sealing structure according to claim 3, wherein, The side wall surface on the pressurizing side in the fitting groove is constituted by a surface perpendicular to the central axis of the resin gasket, the side wall surface on the counter-pressurizing side in the fitting groove is constituted by a surface perpendicular to the central axis of the resin gasket, the tapered surface of the annular protrusion is connected to the side wall surface on the pressurizing side by a curved surface, and the tapered surface of the annular protrusion is connected to the side wall surface on the counter-pressurizing side by a curved surface.
5. 5. A method for assembling a seal structure according to claim 1,2, 3 or 4, comprising: A step of, after the resin gasket is fitted into the mounting member from the pressing side, sliding the resin gasket toward the mounting groove until an end face of the pressing side of the resin gasket passes through a position of a side wall face of the pressing side of the mounting groove, thereby mounting the resin gasket in the mounting groove, and And a step of attaching the attachment member to which the resin gasket is attached to the attachment hole of the attached member.

Description

Sealing structure and method for assembling sealing structure Technical Field The present invention relates to a seal structure including a resin gasket and a method of assembling the seal structure. Background In a portion to be attached to a cylinder head of an engine by an injector, a resin gasket is provided to prevent leakage of high-pressure combustion gas from an annular gap formed between an attachment hole of the cylinder head and the injector. For example, a PTFE gasket having excellent heat resistance and pressure resistance is suitably used. However, in the case of such a gasket, creep phenomenon is advanced by long-term use, and heat shrinkage is increased with time, so that sealability is gradually lowered. Therefore, there is known a technique of providing a tapered surface that expands in diameter from a high pressure side to a low pressure side on a groove bottom surface of a gasket fitting groove provided in an injector, thereby narrowing a gap from the high pressure side to the low pressure side (see patent document 1). By adopting such a configuration, even when thermal shrinkage of the gasket is increased with time, the self-sealing function is exhibited by the pressure generated by the combustion gas, and thus the sealing performance can be maintained. However, even in the case of the above-described structure, in the gasket in which the creep phenomenon is intensified, a gap is generated between the outer peripheral surface of the gasket and the inner peripheral surface of the mounting hole in a low-temperature environment. The gap gradually widens with time, and therefore, a gradual decrease in sealability is unavoidable. Accordingly, a gasket that can further stably exert sealing properties over a long period of time is desired. Prior art literature Patent literature Patent document 1 Japanese patent No. 3830896 Disclosure of Invention Technical problem to be solved by the invention The invention aims to provide a sealing structure and an assembling method of the sealing structure, which can exert stable sealing performance for a long time. Solution for solving the technical problems The present invention adopts the following means to solve the above-described problems. Namely, the sealing structure of the present invention includes: a mounted member having a mounting hole; A mounting member mounted to the mounting hole, and A cylindrical resin gasket for sealing a gap between a pressurizing side, which is pressurized by a pressure of a fluid to be sealed, and a counter pressurizing side, which is opposite to the pressurizing side, by an annular gap provided between the mounting hole and the mounting member, The sealing structure is characterized in that, The mounting member is provided with an annular fitting groove for fitting the resin gasket, and An annular projection having a tapered surface that expands from the pressurizing side toward the counter pressurizing side and a tapered surface that contracts from the pressurizing side toward the counter pressurizing side is provided at the bottom of the fitting groove, and a tip of the annular projection is disposed so as to be offset toward the pressurizing side from a center in a groove width direction in the fitting groove. According to the present invention, when the pressure from the pressurizing side acts on the resin gasket, the resin gasket is pressed against the outer peripheral surface side by receiving the resistance from the tapered surface expanding from the pressurizing side toward the counter pressurizing side, thereby exhibiting the self-sealing function. Further, since the tip of the annular projection is disposed so as to be offset to the pressing side from the center in the groove width direction in the fitting groove, it is possible to suppress occurrence of a gap with the inner peripheral surface of the mounting hole in the vicinity of the outer peripheral surface of the gasket, particularly, offset to the pressing side. Thus, even in the gasket in which the creep phenomenon is intensified, the gap formed between the outer peripheral surface of the gasket and the inner peripheral surface of the mounting hole can be narrowed in the vicinity of the biasing side in the low-temperature environment. Therefore, the gap between the vicinity of the pressurizing side and the inner peripheral surface of the mounting hole in the outer peripheral surface of the gasket is narrowed, and thus leakage of the fluid to be sealed can be suppressed as compared with the case where the gap is wider. The resin gasket may be mounted in the mounting groove at a position biased toward the pressing side, and a gap may be provided between the side wall surface of the mounting groove on the opposite pressing side and the resin gasket in a state where no pressure is applied from the pressing side. This can suppress dispersion of resistance acting on the resin gasket due to pressure from the pressurizing side, and can improve resistance recei