JP2511683B2 - Seal device - Google Patents

Description

The present invention relates to a hydraulic or pneumatic sealing device.

[Conventional technology and its problems]

Conventionally, as shown in FIG. 5, it has a cylindrical piston storage chamber 6 formed by an inner peripheral surface 3 of a circular hole 2 of an outer member 1 and a circular outer peripheral surface 5 of an inner member 4, and In the fluid device F having the cylindrical piston 43 accommodated in the piston accommodating chamber 6 so as to be movable in the axial direction as indicated by the arrow A, the seal ring 41 for the inner peripheral surface 3 and the outer peripheral surface 5 are used. At least two seal rings 42 were required.

Particularly, when the radial clearance dimension H of the piston storage chamber 6 is small-for example, 3 mm to 7 mm-to form the seal grooves 44, 45 on the outer peripheral side and the inner peripheral side of the piston 43, both seal groove 44,
It is necessary to dispose 45 apart from each other in the axial direction, and the piston length dimension L must be set long, which is a problem.
In addition, there is a problem that the strength and rigidity of the piston 43 itself are insufficient. Moreover, the depths of the seal grooves 44, 45 also become smaller by themselves, and the cross sections of the seal rings 41, 42 fitted therein also become smaller, so the sealability is reduced due to slight wear and permanent compression deformation, and the service life is reduced. There is a problem that the durability is short and the durability life is further shortened when used at high temperature.

[Means for solving problems]

A sealing device according to the present invention is configured such that a cylindrical piston storage chamber formed by an inner peripheral surface of a circular hole of an outer member and a circular outer peripheral surface of an inner member, and an axial relative movement in the piston storage chamber. A cylindrical piston housed therein; and a ring-shaped seal ring having a base end surface attached to an axial end surface of the cylindrical piston and arranged in series in the axial direction of the cylindrical piston, and From the axial end surface of the cylindrical piston, a male part having a mushroom-shaped cross section having a rounded bulge at the tip is projected toward the seal ring side, and the male end of the cylindrical piston is attached to the base end surface of the seal ring. The female portion into which the portion fits is provided as a recess, and further, an outer lip that comes into contact with the inner peripheral surface of the outer member is provided on the outer diameter side of the tip side of the seal ring,
An inner lip that contacts the outer peripheral surface of the inner member is provided on the inner diameter side of the tip side of the seal ring, and the seal ring has an outer diameter side
Except for the outer lip / inner lip on the inner diameter side, the inner peripheral surface of the outer member and the outer peripheral surface of the inner member are not in contact with each other to form a gap, and the seal ring has a cross-sectional shape elongated in the axial direction. It is U-shaped.

[Action]

It becomes possible to seal one cylindrical piston with one seal ring.

Further, since the seal ring is arranged in series with the cylindrical piston in the axial direction, the thickness dimension (radial dimension) of the seal ring is set to be substantially the same as the radial clearance dimension of the cylindrical piston housing chamber. can do.

Since the male part has a rounded tip, cracks are less likely to occur inside the seal ring (due to a sudden pressure change or the like), and the fitting operation with the female part of the seal ring can be facilitated.

Especially, the radial clearance of the piston storage chamber (for example, 3m
If it is small (m ~ 7 mm), due to variations in the size and shape of the seal ring and variations in the radial position of the male part, only one of the outer diameter side and the inner diameter side of the seal ring is strong,
There is a risk that the sliding friction resistance may become excessive due to one-side contact with the inner peripheral surface of the outer member / the outer peripheral surface of the inner member, but in the present invention, the seal ring is the inner peripheral surface of the outer member / the outer peripheral surface of the inner member. On the other hand, since the gap is formed, one-sided contact does not occur. That is, while contacting only with the lip on the tip side of the seal ring, the cross-sectional shape is an elongated shape that is long in the axial direction, and the above-mentioned variations in size and shape are sufficiently absorbed by elastic deformation of the seal ring itself, The inner and outer lips on the tip side contact with a sufficiently uniform force to always maintain good sealing performance.

〔Example〕

 Hereinafter, the illustrated embodiment will be described.

In FIGS. 1, 2, and 3, the piston storage chamber 6 is shown.
Is a cylindrical space formed by the inner peripheral surface 3 of the circular hole 2 of the cylindrical outer member 1 and the circular outer peripheral surface 5 of the round rod-shaped inner member 4. A cylindrical piston 7 is housed in the cylindrical piston housing chamber 6 so as to be movable in the axial direction as indicated by arrow A.

Then, 10 is an annular seal ring, the base end surface of which is attached to the axial end surface 8 of the cylindrical piston 7. Then, the piston 7 has a male portion having a bulge at the tip protruding from the axial end surface 8 toward the seal ring 10 side, and the male portion is fitted to the base end surface of the seal ring 10. The female part is recessed.

By the way, in this embodiment, this male part is a ring-shaped protrusion 9 having a mushroom-shaped cross section. Further, the piston 7 is composed of a piston main body 7a having a minute gap between the inner peripheral surface 3 and the outer peripheral surface 5 or in slight contact, and a connecting portion 7b thinner than the piston main body 7a. .

The radial clearance H of the piston storage chamber 6 is approximately 3 mm to 1
It is as small as 0 mm.

The seal ring 10 used in the sealing device according to the present invention,
Such a cylindrical piston 7 is attached to the axial end surface 8 side by using the ring-shaped protrusion 9 having a rounded bulged portion at the tip, and is attached to the outer diameter side on the tip side to the outside. Material 1
An outer lip 11 that contacts the inner peripheral surface 3 and an inner lip 12 that contacts the outer peripheral surface 5 of the inner member 4 are integrally provided on the inner diameter side on the tip side, and have a substantially U-shaped cross section. In other words, the seal ring 10 has a gap portion in which the outer diameter side and the inner diameter side are not in contact with the inner peripheral surface 3 and the outer peripheral surface 5 except the outer lip 11 and the inner lip 12, and the seal is formed. Ring 10
The cross-sectional shape of is a slender U-shape that is long in the axial direction.

More specifically, this seal ring 10
Inserts the ring-shaped ridge 9 of the piston 7 into the concave circumferential groove 14 having a mushroom shape (a dovetail groove) in cross section as the above-mentioned female portion, and mounts it on the axial end surface 8 side of the piston 7. That is, the means G for attaching the seal ring 10 to the piston 7 is the ring-shaped protrusion 9
And a concave circumferential groove 14. It is also preferable to use an adhesive agent or a welding agent together with this. Therefore, the ring-shaped protrusion 9 of the piston 7 is inserted into the base end portion of the seal ring 10, and the rigidity of the base end portion 13 is increased.

Further, at the tip portion 15 of the seal ring 10, the lip 1
1, 12 and receives the fluid pressure P, the lips 11,1
A concave circumferential groove 16 for applying a contact force to 2 is provided as an opening in the axial direction. In addition, in the illustrated example, the inner peripheral portion of the concave circumferential groove 16 has a circular cross section, and an elastic ring 17 such as an O-ring is fitted therein, so that the lips 11 and 12 are elastically resilient to the inner peripheral surface 3 and the outer peripheral surface 5, respectively. The contact pressure is increased. Further, the elastic ring 17 is effective in the case where the operating temperature of the fluid is largely changed-for example, in the range of -30 ° C to + 150 ° C- and the high temperature exceeding 100 ° C. The material of the main body of the seal ring 10 and the elastic ring 17 may be rubber or plastic, but fluororubber is suitable for high temperatures.

The fluid device F shown in FIGS. 1 and 3 has an arrow A.
As described above, the cylindrical piston 7 reciprocates in the axial direction with respect to the stationary outer member 1 and inner member 4, but conversely, the piston 7 stands still and the outer member 1 and inner member 4 move. The same structure can be applied even when the shaft reciprocates in the axial direction.
In short, the seal ring 10 of the present invention can be used to seal a portion that relatively moves in the axial direction. Further, the fluid device F can be applied not only for hydraulic pressure such as hydraulic pressure and water pressure but also for pneumatic pressure, and in addition to the actuator that operates by receiving the pressure P, relative to the axial direction indicated by the arrow A. It does not matter even if the pressure P is generated by performing movement by human power, electric driving force, mechanical external force, or the like.

Next, FIG. 4 shows another embodiment. As is clear from the figure, a plurality of locking projections 18 having rounded ends (having a bulge) are provided at a plurality of tips protruding at a predetermined pitch along the circumferential direction of the axial end surface 8 of the piston 7. , The base end of the seal ring 10
13 has a plurality of blind holes 19 ...
The fitting means G for fitting the seal ring 10 to the piston 7 is formed by fitting. That is, in this embodiment, the locking protrusion 18 is a male part and the blind hole 19 is a female part. In addition, it is preferable to form the seal ring 10 by press-fitting by using elasticity of the seal ring 10 itself or by molding together with the piston 7 in a mold together.

Further, in the figure, instead of the elastic ring 17 of FIG.
A garter spring 20 wound in a coil is used. Alternatively, a leaf spring ring having a V or U-shaped cross section can be used. Then, in the free state, it is obvious that the outer diameter of the outer lip 11 is larger than that of the inner peripheral surface 3 and that the inner diameter of the inner lip 12 is smaller than that of the outer peripheral surface 5, as shown by the two-dot chain line in the figure. Is. The point of giving such a lip margin to both lips 11 and 12 is the same in the case of FIG.

〔The invention's effect〕

Since the present invention is configured as described above, it has the following effects.

The thickness dimension (radial dimension) of the seal ring 10 can be set to be substantially the same as the radial clearance dimension H of the cylindrical piston storage chamber 6, and when the radial clearance dimension H is small (for example, about 3 .About.7 mm), the outer lip 11 and the inner lip 12 can secure a sufficient margin.

Since a sufficient margin can be secured, even if the inner and outer lips 12 and 11 are slightly worn or permanently deformed by compression, the hermeticity can be sufficiently maintained, the durability is excellent, and the life is long.

Compared with the conventional one shown in FIG. 5, since it is not necessary to attach a seal ring to the inner and outer peripheral surfaces of the piston itself by axially shifting it, the length dimension of the piston body 7a of the piston 7 can be reduced, Along with being compact,
Since it is not necessary to form a concave groove for fitting the seal ring on the outer peripheral surface and the inner peripheral surface of the piston 7, this sealing device can be easily manufactured at low cost.

Since the male portion is provided on the axial end surface 8 of the cylindrical piston 7 and the female portion to which the male portion fits is provided on the base end surface of the seal ring 10, the seal ring 10 and the piston 7 are securely connected. In addition, the rigidity of the base end portion 13 of the seal ring 10 increases.

The male part protruding from the piston reinforces the seal ring 10 from the inside like an internal bone,
Is always held in the cylindrical piston storage chamber 6 in a stable posture (without being twisted or tilted). Therefore, the sealing performance is always stable and good.

Since the male part has a rounded tip, cracks are unlikely to occur inside the seal ring 10.

In particular, when the radial clearance H of the piston storage chamber 6 is small (for example, 3 mm to 7 mm), the size of the seal ring 10
Due to variations in shape and variations in the radial position of the male part,
Only one of the outer diameter side and the inner diameter side of the seal ring 10 is strong, and the inner peripheral surface 3 of the outer member 1 and the outer peripheral surface 5 of the inner member 4 are strong.
In addition, the sliding friction resistance may become excessive due to one-sided contact. However, in the present invention, the seal ring 10 has the inner peripheral surface 3 of the outer member 1.
Since a gap is formed on the outer peripheral surface 5 of the inner member 4, one-sided contact does not occur. That is, the contact is made only by the lip on the tip side of the seal ring 10, and the cross-sectional shape is an elongated shape that is long in the axial direction, and the above variations in size and shape are sufficiently absorbed by the elastic deformation of the seal ring 10 itself. Then, the inner and outer lips 12, 11 on the tip side contact with a sufficiently uniform force to always maintain good sealing performance.

[Brief description of drawings]

FIG. 1 is a partial sectional side view showing an embodiment of the present invention, and FIG.
1 is a sectional view taken along the line II-II of FIG. 1, FIG. 3 is an enlarged view of an essential portion of FIG. 1, and FIG. 4 is a sectional view of an essential portion showing a modified example replacing FIG. FIG. 5 is a partial sectional side view showing a conventional example. 1 ... Outer member, 2 ... Circular hole, 3 ... Inner peripheral surface, 4 ... Inner member, 5 ... Circular outer peripheral surface, 6 ... Piston storage chamber, 7 ...
… Cylindrical piston, 8 …… Axial end face, 10 …… Seal ring, 11 …… Outer lip, 12 …… Inner lip.

Front page continuation (56) References Open 54-87345 (JP, U) Open 53-57155 (JP, U) Open 54-32685 (JP, U) Open 61-15343 (JP) , Y2)

Claims (1)

(57) [Claims] 1. A cylindrical piston accommodating chamber formed by an inner peripheral surface of a circular hole of an outer member and a circular outer peripheral surface of the inner member,
A cylindrical piston accommodated in the piston accommodating chamber so as to be relatively movable in the axial direction, and a base end surface thereof is attached to an axial end surface of the cylindrical piston and arranged in series in the axial direction with the cylindrical piston. An annular seal ring is provided, and from the axial end surface of the cylindrical piston, a mushroom-shaped male portion having a mushroom-shaped cross section having a bulged portion with a rounded tip is provided to protrude toward the seal ring side, and On the base end face of the seal ring,
A female portion into which the male portion of the cylindrical piston fits is provided in a concave shape, and further, an outer lip that comes into contact with the inner peripheral surface of the outer member is provided on the outer diameter side of the tip end side of the seal ring, and the seal ring An inner lip that contacts the outer peripheral surface of the inner member is provided on the inner diameter side of the tip side, and the seal ring has an outer diameter side and an inner diameter side other than the outer lip and the inner lip, and the inner peripheral surface of the outer member and the outer periphery of the inner member. As a non-contact with the surface, forming a gap,
The sealing device is characterized in that a cross-sectional shape of the seal ring is an elongated U-shape that is long in the axial direction.