JPH0534387Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a sealing device, in particular, to a sealing device, in particular, to a cylindrical shape of either the outer or inner cylindrical member of two cylindrical members that reciprocate or rotate in a fitted state. The present invention relates to a sealing device that seals fluid pressure between two members by mounting a seal ring in an annular mounting groove with a substantially rectangular cross section provided on a relative movement surface of the members.

(Prior Art) Conventionally, when two cylindrical members are in a fitted state and move reciprocatingly or rotationally, a generally rectangular cross section provided on the relative movement surface of either the outer or inner cylindrical member. There are known sealing devices in which a seal ring is mounted in an annular mounting groove to seal fluid pressure between both members, and one of them is mainly used in power steering devices of automobiles. There is a sealing device. Such sealing devices are constantly required to maintain sealing performance and improve reliability in order to improve steering operability.

By the way, the operating temperature range of the sealing device used in the power steering device is a very wide temperature range (-30 to +
150°C), therefore, it is required to adapt to this wide temperature range and maintain sealing performance at all times.

However, since the seal ring incorporated in the seal device is mainly made of polymeric materials such as synthetic rubber and synthetic resin, dimensional changes in the seal ring due to temperature changes over a wide range as mentioned above are unavoidable. For example, due to contraction or expansion of the seal ring, the fixing surface of the seal ring may come into close contact with the bottom of the annular mounting groove.
When fluid pressure is applied under such conditions, fluid leaks from the gap created between the seal ring and the mating moving surface, resulting in so-called blow-through leakage.

That is, FIGS. 1 to 3 are schematic explanatory diagrams of a sealing device used in a conventional power steering device, in which two members each having a cylindrical surface that makes reciprocating motion and/or rotational motion relative to each other. A mounting groove 3 provided on the cylindrical outer surface 2 of the inner member 1, a cylindrical inner surface 5 of the outer member 4, and an outer surface 6 mounted in the mounting groove 3 of the outer member 4. It consists of a seal ring 10 made of synthetic resin or synthetic rubber that is in sliding contact with the inner surface 5.

Figures 1 to 3 show a simple seal ring 10 with no notches, a seal ring 10 with a notch 7 only on the pressure side, and a seal with a notch 8 only on the fixed surface. An example of a ring 10 is shown.

However, since the seal ring 10 made of synthetic resin or synthetic rubber has a larger linear expansion coefficient depending on temperature than the inner and outer members 1 and 4, when the temperature decreases, the seal ring 10 contracts, and the outer surface 6 of the seal ring 10 contracts. creates a gap between the inner surface 5 of the outer member 4 and the inner surface 5 of the outer member 4. As shown in FIG.
2, when fluid pressure is applied from the side where the end surface 11 of the seal ring 10 is in contact with the side surface 12 of the mounting groove 3 in the direction of the arrow in each figure,
Since it is difficult for the fluid pressure to enter the fixed surface 13 side of the seal ring 10, the sealing performance is insufficient, resulting in the drawback that the blow-through leakage as described above is observed. As shown in FIG. 2, even when the notch 7 is provided, fluid pressure does not act on the fixing surface 13 of the seal ring 10. Further, even if a notch 8 is provided in the inner surface 13 as shown in FIG. 3, fluid pressure does not act on this notch.

In particular, in the example shown in FIG. 1, there is a lot of leakage and the leakage continues. Leakage cannot be stopped depending on the conditions. Figure 2,
In the example shown in FIG. 3, the responsiveness from the time fluid pressure is applied until the fluid pressure acts on the seal ring 10 and stops leaking is poor.

(Problems to be Solved by the Invention) The purpose of the present invention is to solve the problems of the prior art and provide a sealing device, especially for automobiles, which maintains sealing performance over a long period of time and improves reliability. The goal is to provide the following.

(Means for Solving the Problems) Thus, the gist of the present invention is that the seal ring is made of synthetic rubber or synthetic resin, has a substantially rectangular cross section, and has a mating seal ring that is made of synthetic rubber or synthetic resin and has a substantially rectangular cross section. A first notch is provided that communicates a moving surface that is in contact with the moving surface and a fixed surface that faces the bottom surface of the mounting groove, and the first notch is provided in the fixed surface.
This is a sealing device characterized by providing a notch and a second notch that communicates with each other at least in part.

The purpose of the present invention can be achieved by providing one pair of first and second notches, but from the perspective of balancing the action of fluid pressure, two pairs of first and second notches are required. It is preferable to provide them symmetrically.

The dimensions of the first notch are not specified, but when the side surface of the seal ring on the side where fluid pressure acts comes into close contact with the pressure side side surface 6 of the mounting groove due to back pressure etc., the fluid pressure is It is sufficient that the fluid necessary to act on the fixing surface passes through the notch and passes through the second notch of the seal ring.

(Operation) Next, the present invention will be explained in more detail with reference to the accompanying drawings.

4 to 8 show a seal ring device according to the present invention. Identical members are indicated by the same reference numerals.

FIG. 4A is a sectional view of the seal ring according to the present invention, and FIG. 4B is a plan view of FIG. 4A.

The seal ring 10 has a fixed surface 13, a moving surface 6, an end surface 11 on which fluid pressure acts, and a side surface 14 opposite thereto. According to the present invention, the end surface 11
A first notch 15 is provided on the fixing surface 13, and a second notch 16 is provided on the fixing surface 13, and these are in communication at least in part.

5 and 6 are explanatory diagrams of the usage situation of the sealing device according to the present invention, and FIG. 5 shows the situation when the seal ring 10 is contracted, and when fluid pressure is applied at this time, it is immediately fixed. Fluid pressure acts on the surface 13 to expand the sealing ring and restore the sealing function. The situation at this time is shown in FIG. As a result of fluid pressure being applied not only from the pressure side end surface 11 but also from the fixed surface 13, when the seal ring 10 expands and contracts, the seal ring 10 is moved against the groove side surface 14' and the moving surface 5, respectively, as shown by the small arrows in the figure. As shown in the figure, fluid pressure acts in the pressing direction to achieve a sealed state.

FIG. 7 shows another modification, in which the second notch 16 of the seal ring 10 is located on the pressure side end surface 11.
It is a schematic cross-sectional view showing a case where the hole is penetrated to the side surface 14 on the opposite side. In comparison with the case of FIG. 4, the same members are represented by the same reference numerals.

FIG. 8 shows still another modification, and is a schematic partial sectional view of the case where the inner circumferential surface of the seal ring 10 is in contact with the mating motion surface 5. In the case of this example, the outer circumferential surface of the seal ring 10 forms a fixing surface 13, and a notch 16 is provided here.

In this way, the seal ring 10 expands or contracts due to temperature changes, and the fixing surface 13 moves into the mounting groove 3.
When fluid pressure is applied at that time, the fluid pressure passes through the gap created between the moving surface 6 of the seal ring 10 and the mating moving surface 5, causing leakage.

However, according to the present invention, the second notch 16
The end face 11 on the side where pressure is applied to the fixing face 13 of the seal ring 10 and the side face 14 on the non-pressure side opposite thereto are located at a position such that at least a part of the first notch 15 communicates with each other. By connecting them, even in the above-mentioned conditions,
Fluid pressure passes through the first notch 15 and the second notch 1
6 to lift the seal ring 10 from the bottom surface of the mounting groove 3, and further apply fluid pressure to the entire surface of the fixed surface 13 to bring the moving surface 6 of the seal ring 10 into contact with the mating moving surface 5 to maintain sealing performance. let

Therefore, the larger the area of the second notch 16, the better the sealing performance when the seal ring 10 contacts the bottom surface of the mounting groove 3, but if the second notch 16 is too large, the strength of the seal ring decreases. However, wear, etc. will be accelerated and the life of the seal will be shortened.

In another aspect, the second notch 16 is provided only on the side of the end face 11 on the side where pressure acts, of the fixed face 13 of the seal ring 10, and the second notch 16 is provided only on the end face 11 side on the side where pressure is applied
It can also be provided so as not to penetrate up to 4.
In such a configuration, the volume of the side surface 14 on the non-pressure side of the seal ring 10 is increased, so the strength of the seal ring is maintained, and the seal ring is inserted into the gap between the two members on the non-pressure side. It is difficult to protrude and is effective when pressure is high. In terms of the strength of the seal ring, good results can be obtained if the axial length of the second notch 16 is about 2/3 or less of the total thickness of the seal ring, and a depth of 1 mm or less is sufficient. .

Next, the dimensional relationship between the seal ring and the seal ring mounting groove in the seal device according to the present invention _is as follows:
When there is an extreme difference between the axial dimension (H) of the mounting groove, the radial width dimension (W ₁ ) of the seal ring, and the radial width dimension (W) of the mounting groove, that is, the difference between the seal ring and the mounting groove. If the gap between the grooves is too large, it will be difficult for the fluid pressure to press the seal ring against the sealing surface, and the fluid pressure will leak from between the seal ring fixing surface and the bottom of the mounting groove, causing a blow-by phenomenon. Does not maintain seal function.

However, those skilled in the art can appropriately set the appropriate dimensional relationship based on the above description depending on the fluid pressure used.

Next, examples will be described to clarify the effects of the present invention.

Embodiment The seal ring according to the present invention is characterized in that first and second notches are provided on the fluid pressure acting end surface and the fixed surface, respectively.In this example, both of these notches are provided. The purpose of this study is to clarify the synergistic effects of

As an example of the present invention, a seal ring shown in FIG. 4 was used, while as a comparative example, seal rings having structures shown in FIGS. 1, 2, and 3 were used.

The oil leakage properties at low temperatures of sealing devices using each seal ring were evaluated. The material of the seal rings was the same in all cases, and fluorine resin was used.

The results are summarized graphically in Figure 9. The curves represent an example of the present invention, and the curves , , , , , , , , , , , , , , , , , , , , , , , , , , 11, , 10, 10, 10, 10, and 10, respectively, respectively, show the results when the seal rings of FIGS. 1, 2, and 3 are used).

In the case of the comparative examples, the oil leakage rate never becomes less than 200c.c./min in the low temperature range below 0℃, but in the present example, the oil leakage rate does not always decrease under the temperature condition of 0℃ or below.
It never exceeded 100c.c./min.

Moreover, while there was a delay in response in the comparative example, there was no such delay in the example of the present invention.

[Brief explanation of the drawing]

1 to 3 are schematic illustrations of a conventional sealing device; FIGS. 4A and 4B are a sectional view and a plan view, respectively, of a seal ring according to the present invention; FIGS. 5 and 6 are A schematic explanatory diagram of the sealing device according to the present invention: FIGS. 7 and 8 are a schematic cross-sectional view and a schematic partial cross-sectional view, respectively, showing still another modification of the seal ring according to the present invention;
and FIG. 9 is a graph showing test results of the sealing performance of the sealing device according to the present invention together with those of a comparative example. 3... Mounting groove, 5, 6... Movement surface, 10... Seal ring, 11... End surface, 13... Fixed surface, 1
5...first notch, 16...second notch.

Claims (1)

[Claims for Utility Model Registration] (1) An end face 1 made of synthetic rubber or synthetic resin, exhibiting a substantially rectangular cross section, and on the side where fluid pressure is applied.
1, the mating motion surface 5 of the seal ring 10
A first notch 15 is provided that communicates the moving surface 6 in contact with the fixed surface 13 facing the bottom surface of the mounting groove 3, and at least a portion of the first notch 15 and each other are provided in the fixed surface 13. A sealing device characterized in that a second notch 16 is provided in which the two notches communicate with each other. (2) The sealing device according to claim 1, wherein the second notch 16 does not communicate between the end surface 11 and the side surface 14 of the seal ring 10. (3) The sealing device according to claim 1 or 2, wherein two or more pairs of the first notch 15 and the second notch 16 are symmetrically provided in the seal ring 1.