JPH0446116Y2 - - Google Patents

Description

[Detailed description of the invention] A. Field of industrial application This invention is used in fluid pressure cylinders used in many industries, and is used for dual-pressure cylinders that seal the pressure of fluid from along the sliding direction with one cylinder. This invention relates to seals, and particularly to dual-pressure seals with excellent friction characteristics.

B. Prior Art Conventionally, there have been O-rings and X-rings as double-pressure seals, and improved versions of these include the seals shown in Japanese Utility Model Application No. 55-102457. These seals are U-shaped, L-shaped, V-shaped
Unlike seals such as molds, there is no directionality to pressure, and one seal can seal pressure in both directions.
Although it is suitable for the purpose of making the sealing device more compact and at low cost, it has a large sliding friction force, making it difficult to obtain smooth sliding characteristics, and tends to be inferior in durability compared to U-shaped packings. be.

C. Problems to be solved by the invention The invention aims to improve the operating characteristics and durability of the above-mentioned dual-pressure seal, and has excellent operating response at low pressures and smooth operating characteristics at low speeds. This provides a low-friction, dual-pressure seal with excellent durability.

D. Means for Solving the Problems In order to solve the above problems, the present invention provides a circular arc protrusion in the center of the moving side of the double-pressure seal, so that the protrusion and the tip of the protrusion are closer to the fixed part. A moving section consisting of a tapered surface connecting the ends of both side surfaces, and a fixed side surface located on the opposite side from the moving section separated by valleys provided on both sides, with an arc or edge in the center. A protrusion is provided, and the tip of the arc or edge of the fixed side surface and the ends of both side surfaces that are closer to the moving part than the tip of the fixed side surface are tapered at a smaller angle with respect to the axis than the tapered surface of the moving side surface. By forming the seal in the mounting groove with a tied fixing part, the part sandwiched between the valleys provided on both sides can flexibly twist in response to fluid pressure and movement of the piston rod. With,
The above problem is solved by making the entire seal easy to twist within the mounting groove around the tip of the protrusion on the fixed side surface.

E. Example One example of a piston seal, which is one of the dual-pressure seals according to the present invention, is shown in FIG. 1, and another example is shown in FIG. 2.

The double-pressure seal 1 of the present invention shown in FIG. 1 has an arcuate protrusion 4 in the center of the moving side surface, and connects the protrusion 4 with the ends 12 of both side surfaces located on the stationary side from the tip of the protrusion. Moving part 2 consisting of a tapered surface 7
A protruding portion 9 of the fixed side surface formed by an arc or an edge is provided at the center of the fixed side surface that abuts the bottom surface 22 of the annular groove 21, which is separated by the trough 8 provided on the side surfaces 5 and 6, and the protrusion of the fixed side surface is 9 and the end portions 13 of both side surfaces which are closer to the moving part than the tip of the protrusion on the fixed side surface, the angle with respect to the bottom surface 22 of the annular groove is made smaller than the angle with respect to the moving surface 20 of the tapered surface 7 of the moving side surface. Fixed part 3 tied with tapered surface 14
It has a cross-sectional shape that is vertically symmetrical.

Preferably, the height of the protrusion on the moving side is equal to or lower than the height of the protrusion on the stationary side.

However, if the angle of the tapered surface of the fixed part is equal to or greater than the tapered surface of the moving part, the side surface 6 of the fixed part becomes relatively smaller than the side surface 5 of the moving part, and the seal is basically maintained. The strength of the fixed part will be reduced. The behavior of the dual-pressure seal configured in this way is that because the fixed part has a large taper angle, the amount of twist of the entire seal around the tip 9 of the protruding part becomes large, and it is difficult to support the seal when subjected to pressure. As the area of the side surface 6 of the fixing part decreases and the strength decreases, the seal is twisted in the mounting groove and deformation of the fixing part increases, and the tip 9 of the protruding part fits into the corner of the annular groove bottom surface 22, causing the seal to twist in the mounting groove. It tends to enter at an angle, which affects sealing performance.

A plurality of radial grooves 1 are provided on both side surfaces 5 of the moving part 2.
7 or a protrusion (not shown) may be provided.

FIG. 2, which is another embodiment, shows a tapered surface of the movable portion 2 that is larger than the fixed portion 3, and a first tapered surface 15 on the side that is in contact with the circular arc, and a movable portion that is movable compared to the first tapered surface 15. 2 shows a bi-pressure seal with a dynamic side consisting of a second tapered surface 16 configured at a small angle to surface 20; Note that the second tapered surface 16 may have a smaller angle than the tapered surface of the fixing portion 3.

These double-pressure seals according to the present invention are made of a material selected from among various elastic materials such as synthetic rubber and elastomer.

Functions and Effects When a seal made of synthetic rubber or the like is in a stationary state, a phenomenon of sticking occurs between it and the moving surface of the other party, increasing the starting friction. This tendency is particularly strong in squeeze seals such as O-rings.

The double-pressure seal 1 according to the present invention is also a squeeze seal in which the inner and outer protrusions are compressed, and has the property of increasing the starting friction force as described above. As shown in FIG. 2, the frictional force generated at the time of startup is absorbed by the twisting of the moving part 2 around the thin wall part 10 sandwiched between the valley parts 8 and the double-pressure seal around the tip of the protruding part 9 of the fixed part 3. Due to the overall twist, the contact portion of the protrusion 4 of the moving part 2 that is in contact with the moving surface 20 is
It is made smaller by rotating and moving along the circular arc.

In addition, in the figure, the code 24 is the cylinder tube surface,
25 represents a piston.

When the contact part rotates and moves, the radius of torsion of the moving part 2 and the radius of torsion of the entire double-pressure seal centered on the tip of the protrusion 9 are larger than the radius of the arc of the protrusion 4. , the crushing margin of the seal is reduced and the frictional force is reduced.

Therefore, the double pressure seal 1 according to the present invention has the following characteristics:
Even if settings are made to increase the crushing margin to improve sealing performance and durability, the increase in frictional force is small.

By making the height of the protruding part 4 of the moving part 2 lower than the height of the protruding part 9 of the fixed part 3, the moving part 2
and the entire double-pressure seal 1 is easily twisted;
Contributes to reducing frictional force.

When the dual-pressure seal of the present invention has a longitudinal cross section with a height in the axial direction larger than the width in the outward and inner directions,
The tapered surface 7 of the moving part becomes long, and the side surface 5 of the moving part 2 becomes narrow, and cannot have sufficient strength against fluid pressure. As shown in FIG.
and a second tapered surface 16 located on the side surface side at a smaller angle than the first tapered surface, the width of the side surface 5 of the exercise section 2 can be maintained and the strength can be maintained.

According to this configuration, the area of the side surface 5 of the moving part 2 against such pressure can be increased to ensure strength, and at the same time, when the torsion of the moving part 2 or the entire torsion becomes large, the second taper The side surface side of the surface 16 contacts the mating surface 20 to prevent excessive twisting and ensure proper sealing performance.

A plurality of grooves 17 or protrusions (not shown) provided on the side surface 5 of the movement section 2 are arranged so that the movement section 2 has an annular groove on the side surface 2.
This is a pressure introduction path for easily introducing fluid pressure into the valley portion 8 and preventing a blow-through phenomenon even when the groove portion 3 is in close contact with the valley portion 8 .

[Brief explanation of the drawing]

1 and 2 are cross-sectional views of one side of an embodiment of the present invention, and FIG. 3 is a cross-sectional view of the piston portion of a fluid pressure cylinder incorporating the dual-pressure seal of the present invention. It is a figure which shows a twisted state. 1...Seal for both pressures. 2...Exercise club. 3...Fixed part. 4... Protrusion. 7...Tapered surface. 8...
Tanibe. 9...Protrusion. 14...Tapered surface. 15
...First tapered surface. 16...Second tapered surface. 20...Motor aspect. 21...Annular groove. 22...
Annular groove bottom. 23... Annular groove side surface. 24... Cylinder tube surface. 25... Piston.

Claims (1)

[Claims for Utility Model Registration] (1) Two cylindrical members that move relative to each other with a slight gap between them. ,
In a single seal that prevents fluid pressure from leaking from both directions, a circular arc protrusion is provided in the center of the movable side surface, and the protrusion and the ends of both side surfaces that are closer to the fixed part than the tip of the protrusion are connected to each other. A protruding part formed by an arc or an edge is provided at the center of the fixed side surface that abuts the bottom surface of the annular groove, which is separated by a moving part consisting of a tapered surface and a valley provided on both sides. A vertically symmetrical cross-section characterized by comprising a fixed part that connects the tip of the edge and the ends of both sides on the side of the moving part from the tip with a tapered surface having a smaller angle than the tapered surface of the moving side. Double pressure seal. (2) The tapered surfaces constituting the moving side surface are divided into a first tapered surface on the arc side that is in contact with the arc, and a second tapered surface on the side surface that is at a smaller angle to the moving surface than the first tapered surface on the arc side. The dual-pressure seal according to claim 1 of the registered utility model, characterized in that it is composed of a face and a face.