JPH0540655U - Sealing device - Google Patents

Abstract

(57) [Summary] [Purpose] Protect the main seal 3 from foreign matter in the fluid,
In addition, the structure is such that the main seal 3 can maintain good lubricity. [Structure] Seals for foreign matter 10 located on both sides in the axial direction of a main seal are fitted into an annular groove 23 on an outer peripheral surface of a piston 2 and have an annular base 11 partially cut in the circumferential direction, and the annular base 11. Fiber groups 12 that are flocked on the outer periphery of the fiber at a required density and are in sliding contact with the inner peripheral surface of the cylinder body 1, and the fiber groups 12 are flocked at both ends of the annular base 11 that closely opposes in the circumferential direction at the cut portion. Cross each other intricately.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a sealing device used for a fluid pressure cylinder such as a hydraulic cylinder.

[0002]

[Prior Art]

 Conventionally, for example, as a sealing device used for a hydraulic cylinder, there is a sealing device as shown in FIG. That is, in FIG. 4, 1 is a cylinder body, 2 is a piston that reciprocates axially in the inner circumference of the cylinder body 1, and seals the gap between the outer peripheral surface of the piston 2 and the inner peripheral surface of the cylinder body 1. The sealing device has a packing 3 as a main seal.

In a hydraulic cylinder in which pressure acts alternately from both sides of the piston 2, a pair of wear rings 4 functioning as bearings for the piston 2 are arranged on both sides in the axial direction of the packing 3, and further, the packing 3 On both sides in the axial direction and outside the wear ring 4, in order to prevent damage to the wear ring 4 and the packing 2 due to hard foreign substances such as metal powder mixed in the pressure oil, a pair of cast iron or synthetic resin is used. A foreign matter seal 5 is arranged. The packing 3 is mounted in an annular groove 21 formed substantially axially in the center of the outer peripheral surface of the piston 2, and the wear ring 4 is mounted in a pair of annular grooves 22 formed on both sides of the annular groove 21. The foreign matter seal 5 is mounted in an annular groove 23 formed further outside the annular groove 22 and is in sliding contact with the inner peripheral surface of the cylinder body 1.

[0004]

[Problems to be solved by the device]

 However, according to the above-described conventional structure, the foreign matter seal 5 has a shape in which one portion in the circumferential direction is cut in consideration of the ease of mounting in the annular groove 23, as shown in FIG. It is unavoidable that a clearance δ is formed between the cylinder body 1 and the piston 2 at 5a to allow foreign matter to pass therethrough, so foreign matter can be completely prevented from entering the sliding portions of the wear ring 4 and the packing 3. I couldn't. Further, for example, when the above-mentioned cut portion 5a is a rubbing surface extending in the circumferential direction to eliminate the gap δ, the seal 5 for foreign matter seals not only foreign matter but also oil. The wear ring 4 and the packing 3 may be damaged due to insufficient lubrication, and the original function of the foreign matter seal 5 such as protecting the wear ring 4 and the packing 3 cannot be achieved.

The present invention has been made in view of the above problems, and an object thereof is a structure capable of protecting the main seal from foreign matter in the fluid and maintaining good lubricity of the main seal. To do so.

[0006]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, in the sealing device according to the present invention, a main seal and seals for foreign matters located on both axial sides of the main seal are mounted in each of a plurality of annular grooves formed on the outer peripheral surface of the piston. The foreign matter seal is fitted in the annular groove and is cut in the circumferential direction, and the annular base is slidably contacted with the inner peripheral surface of the cylinder body with the required density of hairs planted on the outer periphery of the annular base. The fiber groups are composed of fiber groups, and the fiber groups planted at both ends of the annular base portion that closely opposes each other in the circumferential direction at the cut portion are intricately crossed with each other. Further, in this case, it is preferable that the seal for foreign matter has the fiber groups at both ends of the annular base portion at the cut portion denser than the fiber groups at other portions of the annular base portion.

[0007]

[Action]

 The foreign matter seals provided on both sides of the main seal in the axial direction block the passage of foreign matter in the fluid by the fiber groups that are planted at the required density on the outer circumference of the annular base and are in sliding contact with the inner circumferential surface of the cylinder body. It also functions as a kind of filter that allows the passage of fluid. The annular base of the foreign material seal is partially cut in the circumferential direction in order to facilitate mounting in the annular groove of the piston, but at both ends of the annular base that are closely opposed to each other in the circumferential direction at the cut portion. Since the flocked fiber groups intersect with each other, it is possible to allow foreign matter to pass through the sliding parts of the fiber groups that project toward the outer peripheral side of the annular groove and substantially block foreign matter. No circumferentially separated portion is formed.

[0008] In this case, the fiber groups at both ends of the annular base are flocked at a higher density than the fiber groups at other portions of the annular base, so that the fiber ends at the both ends have sufficient tips. Since it spreads in the circumferential direction with a certain density and intersects with each other, it is possible to prevent the density of the fibers from becoming coarse at this portion and the sealing property against foreign matter from being deteriorated.

[0009]

【Example】

 FIG. 1 shows an embodiment of a sealing device according to the present invention. As with the conventional structure of FIG. 4 described above, 3 is mounted in the annular groove 21 of the piston 2 and the inner circumference of the cylinder body 1 is shown. A packing 4 as a main seal that is in airtight sliding contact with the surface is a pair of wear rings mounted in the annular grooves 22 on both axial sides of the annular groove 21. A pair of foreign matter seals 10 are disposed on both sides of the packing 3 in the axial direction and outside the wear ring 4, and are mounted in the outermost annular grooves 23 on the outer peripheral surface of the piston 2, respectively.

As shown in FIGS. 2 and 3, the foreign matter seal 10 is made of a synthetic resin annular base portion 11 fitted to the bottom of the annular groove 23 and partially cut in the circumferential direction, and the annular base portion. The fiber group 12 is electrostatically flocked on the outer periphery of the fiber 11 at a required density so that the tips of the fibers are in sliding contact with the inner surface of the cylinder body 1. The fiber group 12 is in contact with the inner side surface of the annular groove 23 on both sides in the axial direction (width direction), and in the fiber group 12, both end portions of the annular base portion 11 which face each other in the circumferential direction at the cutting portion 10a face each other. In the fiber group 12a planted in 11a, the hair tips protruding toward the outer peripheral side of the annular groove 23 spread in the circumferential direction and intersect each other. Furthermore, the fiber group 12a in this portion is the fiber group 12b in the other portion. The hair is densely planted.

That is, in this embodiment, since the foreign substance seal 10 has the annular base portion 11 partially cut in the circumferential direction in order to facilitate the mounting of the piston 2 in the annular groove 23, A gap δ opened in the circumferential direction is formed between the both ends 11a, 11a of the annular base portion 11 that closely opposes each other in the circumferential direction at the cutting portion 10a. Due to the high density, the tips of the hair are spread in the circumferential direction and intersect each other while maintaining the required density. For this reason, the sliding portion of the fiber group 12 protruding to the outer peripheral side of the annular groove 23 does not form a circumferentially separated gap through which foreign matter can pass, and the dense fiber group 12 is formed in the cylinder. Hard foreign matter such as metal powder mixed in the oil is separated from the oil entering the sliding portion between the inner peripheral surface of the body 1 and the wear ring 4 and the packing 3.

[0012] Fig. 2 shows that the annular base portion 11 of the foreign matter seal 10 is cut straight, but this is cut into a bias shape as shown in Fig. 5, or in the axial direction. Various shapes can be applied, such as a cut shape having a stepped rubbing portion extending in the circumferential direction, and the flock density of the fiber group 12 can be arbitrarily selected in consideration of the viscosity of the fluid and the like. good. Further, the packing 3 which is the main seal is not limited to the example shown in the drawing, and various structures can be applied.

[0013]

[Effect of the device]

 According to the sealing device of the present invention, the seals for foreign matters in which fiber groups are planted are provided on both sides in the axial direction of the main seal. Despite the fact that some parts have been cut off, the sliding part of the fiber group that effectively blocks foreign matter does not have a gap through which foreign matter can pass. It is possible to prevent this invasion, and to further enhance this effect by flocking the fibers at both ends of the annular base cut in the circumferential direction with high density. Moreover, since this foreign matter seal allows the passage of fluid, it is possible to prevent foreign matter from entering while maintaining good lubricity of the main seal.

[Brief description of drawings]

FIG. 1 is a half cross-sectional view of a sealing device according to an embodiment of the present invention in a mounted state in relation to a hydraulic cylinder.

FIG. 2 is a perspective view of an essential part in the same mounted state.

FIG. 3 is a front view of relevant parts in the same mounted state.

FIG. 4 is a half cross-sectional view of a conventional sealing device in a mounted state in relation to a hydraulic cylinder.

FIG. 5 is a partial perspective view of the same as the mounted state.

[Explanation of symbols]

 1 Cylinder Body 2 Piston 3 Packing (Main Seal) 4 Wear Ring 10 Foreign Object Seal 10a Cutting Part 11 Annular Base 11a Ends 12, 12a, 12b Fiber Group 21,22,23 Annular Groove δ Gap

Claims (2)

[Scope of utility model registration request] 1. A main seal 3 and a seal 10 for foreign matter located on both axial sides of the main seal 3 are a piston 2
The foreign substance seal 10 is attached to each of the plurality of annular grooves 21 and 23 formed on the outer peripheral surface of the, and the annular base portion 11 is fitted in the annular groove 23 and partially cut in the circumferential direction. The cutting portion 1 is composed of a fiber group 12 which is planted on the outer periphery of the base portion 11 at a required density and is in sliding contact with the inner peripheral surface of the cylinder body 1.
Both ends 11 of the annular base 11 that face each other in the circumferential direction at 0a
A sealing device characterized in that the fiber groups 12a planted on a are intricately crossed with each other. 2. The seal 10 for foreign matter according to claim 1, wherein the fiber group 12a of both end portions 11a of the annular base portion 11 of the cutting portion 10a is higher than the fiber group 12b of the other portion of the annular base portion 11. A sealing device characterized by being flocked at a density.