JPH0128372Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to a sealing device that prevents the flow of fluid between two cylindrical members that make relative reciprocating or rotating motion, and relates to a sealing device that uses fluid pressure or It is widely used as a seal for piston cylinder devices, valves, power steering devices, etc. that generate electricity.

(B) Prior art and its problems A conventional technology is installed in a groove provided on either surface of two relatively movable surfaces of two cylindrical members that reciprocate or rotate relative to each other. A back ring made of elastic synthetic rubber is attached to the bottom of the back ring, and a synthetic rubber back ring is provided on the groove opening side of the back ring to prevent fluid flow between the two cylindrical members (hereinafter also referred to as a "seal"). A seal device that combines a seal ring made of resin or thermoplastic elastomer is generally called a slipper seal. In particular, the seal ring of a slipper seal used for purposes such as power steering devices that require high sealing performance has a pressure introduction groove provided on the side surface of the seal ring.

FIG. 4 shows a conventional seal ring, and FIG. 5 is an explanatory diagram of a state in which this conventional seal ring is installed. The pressure introduction grooves 2, 2' provided in the conventional seal ring 1 are of the same size on the side of the seal ring on both the sealing surface side and the back ring side, that is, they are substantially perpendicular to the sealing surface. A conventional example equipped with a seal ring having pressure introducing grooves 2, 2' having such a shape will be described with reference to FIG. The two cylindrical members 4 and 5 perform a reciprocating or rotational movement relative to each other about the axis x-x. The groove 6 of the cylindrical member 4 is an annular groove 6 with a rectangular cross section formed in the radial direction from the surface of the cylindrical member 4 among the two surfaces on which the cylindrical members 4 and 5 move relative to each other. , the central axis of the groove is the same axis x-x as the cylindrical members 4 and 5.
An elastic back ring 3, which is an annular body with a circular cross section, is pushed into the bottom of this annular groove 6, and a seal ring 1 is attached to the outside of the back ring 3. The outer circumferential surface of the seal ring, which is pushed outward by the force and serves as a sealing surface, is pressed against the moving surface of the cylindrical member 5. The pressure introduction grooves 2, 2' function to apply a pressing force to the sealing surface of the seal ring 1 against the moving surface of the cylindrical member 5 in accordance with fluctuations in fluid pressure, thereby enhancing the sealing effect. In a sealing device having such a configuration, when the pressure inside the annular groove 6 increases during use, the back ring 3 gradually deforms, and a portion of it deforms into the pressure introduction grooves 2 and 2' provided on the side surface of the seal ring. Back ring 3, particularly when used under high pressure or for long periods of time.
There was a tendency for blistering to occur, which caused fluid leakage.

(d) Means for solving the problem The present invention provides a method for solving the problem by reducing the pressure in the back ring 3 without losing the function of the pressure introduction groove provided in the seal ring 1.
In order to prevent peeling, the pressure introduction grooves 2 and 2' provided in the seal ring 1 are made deeper on the sealing surface side and shallower on the back ring 3 side, so that the back ring 3 is deformed by pressure and a part of it is The purpose of the present invention is to prevent or minimize the possibility that the back ring 3 will peel off, and to prevent or minimize the possibility that fluid will enter the pressure introduction grooves 2, 2'. The object of the present invention is to provide a device with no or very little leakage.

(e) Examples Two examples of the seal ring of the present invention are shown in Figs. 1 and 2, and Fig. 3 shows these seal rings 1.
It is an explanatory view where A and 1B are installed in the groove. As can be seen in the figure, the pressure introduction grooves 2A and 2'A of the seal ring 1A in Fig. 1 are formed with a deep curved surface on the sealing surface side and a shallow curved surface on the back ring side. The introduction grooves 2B and 2'B are formed with a deep plane on the sealing surface side and a shallow plane on the backling side.

(F) Function and Effect As mentioned above, the pressure introduction groove of the seal ring of the present invention is a tapered groove that is sufficiently shallow on the back ring side compared to the sealing surface side. When installed in the groove as shown in Figure 3, even if pressure is applied to the back ring, the back ring side is shallow (narrow), so it will hardly get stuck in the groove, and therefore the back ring 3 will hardly be peeled off and the durability of the sealing device will be improved. This is something that can improve performance and reliability.

Note that the pressure introduction groove provided on the side of the seal ring is
If the seal ring is simply made shallow, the seal ring will come into pressure contact with the side surface of the groove due to the fluid pressure and protrude into the gap between the two cylindrical members 4 and 5, and the effect of introducing pressure will be lost.

[Brief explanation of the drawing]

Figures 1 and 2 are diagrams of the seal ring of the present invention, Figure 3 is an explanatory diagram of the seal ring of the present invention installed in a groove, Figure 4 is a diagram of the conventional seal ring, and Figure 5 is a diagram of the conventional seal ring. The figure is an explanatory diagram of a conventional seal ring installed in a groove. 1, 1A, 1B... Seal ring, 2, 2A,
2B...Pressure introduction groove cross section, 2', 2'A, 2'B...
... Pressure introduction groove seen from above, 3... Back ring, 4, 5... Cylindrical member, 6... Annular groove.

Claims (1)

[Scope of utility model registration request] An elastic back ring attached to the bottom of a groove provided on either surface of two relatively movable surfaces of two cylindrical members that reciprocate or rotate relative to each other; In a sealing device that is combined with a seal ring that is attached to the groove opening side and prevents the flow of fluid between the two cylindrical members, the side surface of the seal ring is deep on the sealing surface side and shallow on the back ring side. A sealing device characterized by having a tapered groove.