JPH0725484Y2 - Sealing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a sealing device, and more particularly to an improvement of a sealing device incorporated between two members that move relative to each other, such as a piston and a cylinder.

[Conventional technology]

The applicant of the present application has previously applied for a sealing device having a high voltage and a low sliding resistance, as shown in FIG. 4 (Japanese Utility Model Publication No. 63-3496).
No.), the present invention is a further improvement thereof.

[Problems to be solved by the device]

That is, in the sealing device of FIG. 4, it is conceivable to reduce the contact width (l) of the sliding surface (b) in order to further reduce the sliding resistance of the synthetic resin seal ring (a). The mounting groove (f) considering the overall balance
Including the above, it is necessary to reduce the cross section of the entire sealing device (to reduce the size in a similar manner). However, if the cross-section of the entire device is reduced, the pressure resistance is reduced, and the seal ring (a) may protrude into the gap (g) and be damaged. In order to improve the pressure resistance, the gap (g) may be made small, but in general, the gap (g) cannot be made so small in order to allow the eccentricity of the sliding portion. Therefore, as shown in FIG. 5, it is conceivable to insert a metal backup ring (d) into the depth of the mounting groove (f), but in this case, the eccentricity followability of the sealing device decreases. The seal will not work properly. Also, as shown in FIG.
Backup ring (d) for eccentricity tracking
If a gap (h) is set on the outer periphery of the, the packing (c) made of a rubber-like elastic material may protrude into the gap (h) and be damaged. Therefore, it is conceivable to embed a small backup ring (e) in the seal ring (a) as shown in FIG. 7, but in this case, the handling of the backup ring (e) is very complicated. Also, the eighth
As shown in the figure, if the backup ring (e) has the same thickness as the seal ring (a), the packing (c) will be sandwiched between the two (a) and (e) and damaged.

[Means for Solving the Problems]

In view of the above points, the present invention aims to reduce sliding resistance without causing the above-mentioned various inconveniences.
To achieve this object, as shown in claim 1, a seal ring made of synthetic resin having a taper at one end of a sliding surface, and a rubber-like elastic material arranged on the outer periphery of the seal ring. 1 packing, a backup ring made of metal or synthetic resin covering the other end side and the outer peripheral side of the seal ring and the packing, and a second packing made of a rubber-like elastic material arranged on the outer circumference of the backup ring. A sealing device is provided.

The sealing device according to the second aspect of the invention is a sealing ring made of synthetic resin in which the inner and outer circumferences of the sealing device of the first aspect are interchanged so that one end of the sliding surface is tapered, and A first packing made of rubber-like elastic material arranged on the circumference, a backup ring made of metal or synthetic resin covering the other end side and the inner circumference side of the seal ring and the packing, and arranged on the inner circumference of the backup ring And a second packing made of rubber-like elastic material.

Further, the sealing device according to the third aspect is characterized in that the second packing is a U-packing with reference to the first or second aspect.

[Action]

The sealing device of the present invention having the above-described structure includes the backup ring to prevent the seal ring from protruding, and also has the second packing on the outer circumference or the inner circumference of the backup ring to improve the eccentricity followability. When the U packing is used as the second packing, the eccentricity followability can be further improved.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings.
The sealing device of FIG. 1 comprises a synthetic resin seal ring (1) provided with a taper (3) at one end of a sliding surface (2), and a rubber-like elastic member arranged on the outer periphery of the seal ring (1). Material first packing (4) and the seal ring (1)
And the cross section L to cover the other end and the outer peripheral side of the packing (4).
Metal shaped backup ring (5)
And a second packing (6) made of a rubber-like elastic material arranged on the outer periphery of the backup ring (5), and these are collectively attached to a mounting groove (9) formed on the inner peripheral wall of the cylinder (8). Is incorporated into. A very small gap (10) is set on the inner periphery of the backup ring (5) when no pressure is applied, and the backup ring (5) is compressed by pressure in a pressurized state and the gap (10) is formed. It is molded from a material that has the strength to substantially eliminate 10). Further, the hardness of the second packing (6) is set lower than the hardness of the first packing (4) in order to improve the eccentricity following property.

In the sealing device, the backup ring (5) prevents the seal ring (1) from protruding, and the second packing (6) improves the eccentric followability.
As a result, even if the contact width of the sliding surface (2) is reduced to reduce the sliding resistance and the entire cross section is made smaller, it is possible to prevent the above-mentioned various inconveniences from occurring. The backup ring (5) may have a U-shaped cross section as shown in FIG. 2, but in this case, a communication hole (7) is provided. In this embodiment, the rod seal is taken as an example to assemble the sealing device on the cylinder (8) side, but the piston seal can be constructed by only reversing the inner and outer relations.

FIG. 3 shows another embodiment of the present invention in which the second packing (6) is replaced with an U ring (6) to improve the eccentricity following property. That is, according to the O-ring, when the amount of eccentricity becomes excessive, the sealing performance is deteriorated due to the reduction of the tightening margin due to the settling, and the sliding resistance caused by the contact between the piston (or rod) and the cylinder (8) due to the influence. However, the U packing (6 ') having excellent eccentricity absorbability can eliminate these concerns in advance. The replacement with the U packing (6 ') is the first
The sealing device shown in FIG. 2 is not limited to the sealing device shown in FIG.

[Effect of device]

As described above, the sealing device of the present invention is provided with the backup ring to prevent the seal ring from protruding, and to provide the second ring on the outer circumference or the inner circumference of the backup ring.
It is possible to provide an improved product in which the sliding resistance is further reduced as compared with the prior art disclosed in the above publication, by providing the packing of (1) to improve the eccentricity following property. Further, when the U packing is used for the second packing, the eccentricity followability can be further improved.

[Brief description of drawings]

1 to 3 are half-cut sectional views of a sealing device according to an embodiment of the present invention, and FIGS. 4 to 8 are half-cut sectional views of a conventional sealing device. (1) Seal ring, (2) Sliding surface, (3) Taper (4) (6) Packing, (5) Backup ring (6 ') U packing, (7) Communication hole, (8) Cylinder (9) Mounting groove

Claims (3)

[Scope of utility model registration request] 1. A synthetic resin seal ring having a taper at one end of a sliding surface, a rubber-like elastic first packing disposed on the outer periphery of the seal ring, and the seal ring and the packing. A sealing device including a metal or synthetic resin backup ring covering the other end side and the outer peripheral side, and a second packing made of a rubber-like elastic material arranged on the outer periphery of the backup ring. 2. A synthetic resin seal ring having a taper at one end of a sliding surface, a rubber-like elastic first packing arranged on an inner circumference of the seal ring, the seal ring and the packing. A sealing device including a backup ring made of metal or synthetic resin that covers the other end side and the inner peripheral side of the backup ring, and a second packing made of a rubber-like elastic material arranged on the inner periphery of the backup ring. 3. The sealing device according to claim 1 or 2, wherein the second packing is a U packing.