JP2020193647A - Buffer ring and ceiling system - Google Patents

Abstract

To obtain a technology that effectively buffers a fluid pressure to protect a main seal.SOLUTION: A buffer ring (11) is disposed in an annular groove (10) provided at an inner periphery of a housing (a cylinder 2) which is located closer to a sealing object fluid (O) side than a main seal which seals an annular gap between a shaft part (a rod 3) which reciprocates and the inner periphery of the housing (the cylinder 2). The buffer ring (11) includes: an annular body part (15) which can slide on the shaft part (the rod 3); a body side slit (12) provided on a surface of the body part (15) disposed at the sealing object fluid (O) side; and a lip (14) extending from an outer periphery of the body part (15) toward the seal object fluid (O) side and a bottom surface (an upper bottom surface 10a) of the annular groove (10). A lip side slit (12a) is provided at a tip of the lip (14).SELECTED DRAWING: Figure 4

Description

The present invention relates to buffering and a sealing system comprising the buffering.

In general, hydraulic cylinders that reciprocate rods by flood control are widely used in various industrial machines such as construction machines.
Conventionally, as a configuration applicable to such a hydraulic cylinder, a sealing system having a plurality of seals and sealing the oil side and the atmosphere side, which are the pressure side, is known.

Patent Document 1, which is an example of the prior art, includes a buffer portion S11 that buffers fluid pressure, a main seal portion S12 that mainly suppresses (prevents) leakage of the fluid to be sealed inside the hydraulic cylinder to the outside, and mainly dust. A sealing system S10 including a dust seal portion S13 that suppresses (prevents) the intrusion of the fluid is disclosed. Further, Patent Document 1 discloses an example in which a buffer ring and a backup ring are arranged in a buffer portion, but as another example, Patent Documents 2 and 3 include a portion sliding on a shaft portion and other parts. A buffer portion having a structure in which a member different from the portion is arranged is disclosed.

International Publication No. 2013/172094 Japanese Unexamined Patent Publication No. 2001-343074 Japanese Unexamined Patent Publication No. 2008-39080

According to the above-mentioned prior art, it is possible to seal between the inside and the outside of the fluid pressure cylinder, but there is room for improvement in the buffering of the fluid pressure.

The present invention has been made in view of the above, and an object of the present invention is to obtain a technique for protecting the main seal by effectively buffering the fluid pressure.

The present invention, which solves the above-mentioned problems and achieves the object, covers the inner circumference of the housing on the fluid side to be sealed with respect to the main seal that seals the annular gap between the reciprocating shaft portion and the inner circumference of the housing. A buffer ring arranged in the provided annular groove, the annular body portion slidable on the shaft portion, and the main body side slit provided on the surface of the body portion arranged on the sealing target fluid side. A buffer ring including a lip extending from the outer periphery of the body portion toward the fluid side to be sealed and toward the bottom surface of the annular groove, and a lip side slit provided at the tip of the lip.

In the buffering of the above configuration, it is preferable that the lip can be brought into close contact with the bottom surface of the annular groove.

Alternatively, the present invention is a sealing system including the main seal, a dust seal arranged in an annular groove provided on the inner circumference of the housing on the atmosphere side of the main seal, and a buffering having the above configuration. ..

According to the present invention, it is possible to protect the main seal by effectively buffering the fluid pressure.

It is a schematic cross-sectional view which shows the sealing system which concerns on embodiment. It is a perspective view which shows the buffering which concerns on embodiment. It is a breaking perspective view which shows by cutting out a part of the buffering shown in FIG. It is a schematic cross-sectional view which shows the buffering in the sealing system shown in FIG. It is a figure which shows the behavior when the pressure is applied from the sealing target fluid side of the buffering which concerns on embodiment. It is a figure which shows the seal state of the buffering which concerns on embodiment. It is a figure which shows the back pressure occurrence of the buffering which concerns on embodiment. It is a schematic cross-sectional view which shows the sealing system which is a comparative example. It is a perspective view which shows the buffering which is a comparative example, and is It is a breaking perspective view which shows by cutting out a part of the buffering shown in FIG. It is a comparative example, and is the schematic cross-sectional view which shows the buffering in the sealing system shown in FIG. It is a figure which shows the behavior when a pressure is applied from the sealing target fluid side of the buffering which is a comparative example. It is a figure which shows the back pressure occurrence of the buffering which is a comparative example. It is a figure which shows after the buffering which is a comparative example moved to the fluid side to be sealed.

Embodiments of the present invention will be described below with reference to the drawings.
However, the present invention is not limited to the description of the following embodiments.

<Embodiment>
FIG. 1 is a schematic cross-sectional view showing the sealing system 1 according to the present embodiment.
The sealing system 1 shown in FIG. 1 has a fluid O side to be sealed and an atmosphere A side in an annular gap between the rod 3 which is a reciprocating shaft portion and the inner circumference of a cylinder 2 which is a housing surrounding the rod 3. By sealing the space between the two, the leakage of the fluid O to be sealed to the atmosphere A side is prevented, and the invasion of dust to the fluid O side to be sealed is prevented.
Here, when the sealing system 1 is applied to a hydraulic cylinder, the fluid O to be sealed is oil.

The cylinder 2 has a hollow cylindrical shape having a shaft hole, and a rod 3 is arranged in the shaft hole, and the rod 3 reciprocates.
In addition, annular grooves 10, 20, and 30 are sequentially provided on the inner circumference of the shaft hole of the cylinder 2 from the fluid O side to be sealed toward the atmosphere A side.
That is, the annular groove 10 is provided on the inner circumference of the cylinder 2 on the fluid O side to be sealed with respect to the annular groove 20, and the annular groove 30 is provided on the inner circumference of the cylinder 2 on the atmosphere A side of the annular groove 20. Has been done.

The sealing system 1 shown in FIG. 1 includes a buffer ring 11 arranged in the annular groove 10, a main seal 21 and a backup ring 22 arranged in the annular groove 20, and a dust seal 31 arranged in the annular groove 30. , Equipped with.
The buffer ring 11, the main seal 21, the backup ring 22, and the dust seal 31 have an annular shape slidable on the rod 3.

The main seal 21 mainly prevents a fluid from leaking from the sealing target fluid O side.
The buffering 11 has a main body side slit 12, a lip 14, and a body portion 15, and is arranged on the sealing target fluid O side with respect to the main seal 21 to buffer the pressure of the sealing target fluid O, for example, the oil pressure.
The dust seal 31 prevents dust from entering from the atmosphere A side.

FIG. 2 is a perspective view showing the buffering 11 according to the present embodiment, and FIG. 3 is a breaking perspective view showing a part of the buffering 11 shown in FIG.
Note that FIG. 3 shows a partially enlarged view A and a partially enlarged view B.
The partially enlarged view A is an enlarged view showing a cut-out portion of the buffer ring 11 at a position of the slit 12 on the main body side.
The partially enlarged view B is an enlarged view showing a cut-out portion of the buffer ring 11 at a position where there is no slit 12 on the main body side.

As shown in FIG. 3, the buffer ring 11 is formed with a slope 13 by chamfering a part of the square ring having a substantially quadrangular cross-sectional shape.

Further, as the material of the buffering 11, polytetrafluoroethylene (PTFE) can be exemplified.
When polytetrafluoroethylene is used as the material of the buffering 11, the slidability of the buffering 11 with respect to the rod 3 can be increased.

As shown in FIGS. 1 to 3, two slits 12 on the main body side are provided on the surface of the body portion 15 of the buffer ring 11 arranged on the fluid O side to be sealed, that is, one surface substantially perpendicular to the central axis. ing.
The two main body side slits 12 face each other with the center of the buffer ring 11 interposed therebetween.
Further, a lip 14 is provided on the entire outer circumference of the body portion 15 of the buffer ring 11.

FIG. 4 is a schematic cross-sectional view showing the buffering 11 in the sealing system 1 shown in FIG.
As shown in FIG. 4, the buffer ring 11 arranged in the annular groove 10 of the cylinder 2 is chamfered with the main body side slit 12 provided on the sealing target fluid O side and the atmosphere A side and the rod 3 side. The slope 13 provided in the above and the lip 14 extending from the outer periphery of the body portion 15 toward the fluid O side to be sealed and the upper bottom surface 10a of the annular groove 10 are provided.
A lip side slit 12a is provided at the tip of the lip 14.

FIG. 5 is a diagram showing the behavior when the pressure P1 is applied from the sealing target fluid O side of the buffering 11 according to the present embodiment.
When the pressure P1 is applied from the fluid O side to be sealed, the lip 14 of the buffering 11 expands in the direction in which the tip thereof contacts the upper bottom surface 10a of the annular groove 10 due to the fluid resistance.
Here, this causes the lip 14 to come into close contact with the upper bottom surface 10a of the annular groove 10.
Further, the buffering 11 moves in the annular groove 10 toward the atmosphere A side.
Although leakage from the lip side slit 12a occurs at the tip of the lip 14, the sealing region by the lip 14 is large, and the amount of fluid leakage is small.

FIG. 6 is a diagram showing a sealed state of the buffering 11 according to the present embodiment.
As described with reference to FIG. 5, in the buffering 11, the leakage of the fluid from the sealing target fluid O side is small.
Therefore, according to the buffering 11 according to the present embodiment, the movement to the atmosphere A side, which is the anti-pressure side, is completed in a short time.
That is, the buffering 11 to which the pressure is applied from the sealing target fluid O side is quickly put into the sealing state.
Therefore, the main seal 21 is protected from the application of fluid pressure in a short time.
Further, when the buffering 11 is in the sealed state, the periphery of the lip 14 is in the hydrostatic pressure state.
Therefore, an excessive force that spreads the lip 14 does not act, and it is possible to prevent the lip 14 from tearing from its root.
Therefore, according to the buffering 11 according to the present embodiment, the main seal 21 can be protected for a long period of time, and the life of the main seal 21 can be extended.

FIG. 7 is a diagram showing the time when back pressure is generated in the buffering 11 according to the present embodiment.
As shown in FIG. 7, when the back pressure P2 is generated on the main seal 21 side, the buffering 11 can leak fluid from the main body side slit 12 and the lip side slit 12a, so that the accumulated pressure can be avoided. ..
Further, even when the pressure P1 is applied from the fluid O side to be sealed and the lip 14 expands due to the fluid resistance, the contact width of the lip 14 becomes large and the areas of the main body side slit 12 and the lip side slit 12a are small. The lip 14 collapses due to the back pressure and the viscosity of the fluid.
Therefore, the fluid path is not blocked and the fluid can leak.

Here, a comparative example including the buffering 111 instead of the buffering 11 according to the present embodiment will be described.

FIG. 8 is a schematic cross-sectional view showing a sealing system 101 as a comparative example.
The sealing system 101 shown in FIG. 8 is different in that the annular groove 10 is provided with the buffering 111 in place of the buffering 11 of the sealing system 1 shown in FIG. 1, and the other configurations are the same.
The buffering 111 is arranged in the annular groove 10, and the buffering 111 is slidable with respect to the rod 3.
The buffering 111, like the buffering 11, buffers the pressure of the fluid O to be sealed, for example, the oil pressure.

FIG. 9 is a perspective view showing the buffering 111 which is a comparative example, and FIG. 10 is a fracture perspective view showing a part of the buffering 111 shown in FIG.
As shown in FIGS. 9 and 10, the buffer ring 111 is a square ring having a substantially quadrangular cross-sectional shape, but a part thereof may be chamfered as described later.

As shown in FIGS. 9 and 10, two slits 112 are provided on one of the surfaces of the buffering 111 arranged on the sealing target fluid O side, that is, a surface substantially perpendicular to the central axis.
The two slits 112 are provided so as to face each other with the center of the buffering 111 interposed therebetween.
Further, the buffering 111 is partially chamfered like the buffering 11.

FIG. 11 is a comparative example and is a schematic cross-sectional view showing the buffering 111 in the sealing system 101 shown in FIG.
As shown in FIG. 11, the buffering 111 arranged in the annular groove 10 is provided by chamfering the slit 112 provided on the sealing target fluid O side and the atmosphere A side and the rod 3 side. A slope 113 and a slope 113 are provided.
The slope 113 is the same as the slope 13 of the buffering 11 shown in FIG.
Further, a gap 115 is formed between the buffering 111 and the upper bottom surface 10a of the annular groove 10, and a gap 116 is formed between the buffering 111 and the side wall surface 10b of the annular groove 10 on the fluid O side to be sealed. Will be done.

FIG. 12 is a diagram showing the behavior of the buffering 111 when the pressure P1 is applied from the sealing target fluid O side of the buffering 111, which is a comparative example.
As shown in FIG. 12, in the buffering 111, the pressure P1 from the fluid O side to be sealed is dispersed into the pressure P3 on the side wall surface 10c on the atmospheric A side of the annular groove 10 and the pressure P4 on the rod 3. It escapes and protects the main seal 21 from the pressure P1 on the O side of the fluid to be sealed.

FIG. 13 is a diagram showing a back pressure generation of the buffering 111, which is a comparative example.
As shown in FIG. 13, when the back pressure P5 is generated on the main seal 21 side, which is the atmosphere A side, the buffering 111 moves to the sealing target fluid O side.

FIG. 14 is a diagram showing the buffering 111, which is a comparative example, after being moved to the sealing target fluid O side.
As shown in FIG. 14, when the buffering 111 moves to the fluid O side to be sealed, a gap 115 is formed between the buffering 111 and the upper bottom surface 10a of the annular groove 10, and the buffering 111 and the annular groove 10 are formed. A gap 117 is formed between the side wall surface 10c and the side wall surface 10c.
In this way, as shown in FIG. 14, a leak path is generated from the atmosphere A side through the gap 117, the gap 115, and the slit 112, and the pressure accumulation due to the pressure P5 can be avoided.

However, the buffering 111, which is a comparative example, may take time to reach the sealed state.
When the rod 3 is driven from the atmosphere A side to the sealing target fluid O side while the buffering 111 is in contact with the surface of the annular groove 10 on the sealing target fluid O side, a back pressure pressure P5 is generated.
Then, when the pressure P1 is applied from the sealing target fluid O side, the buffering 111 starts moving, and the sealing target fluid on the sealing target fluid O side moves to the atmosphere A side through the slit 112 and the gaps 115 and 117. Leak.
The buffering 111 that has started to move moves to the atmosphere A side, and the fluid on the sealing target fluid O side leaks between the annular groove 10 and the buffering 111.
When the buffering 111 reaches the side wall surface 10c on the atmosphere A side of the annular groove 10, the sealed state is reached.

As described above, according to the buffering 111 which is a comparative example, a fluid leak occurs from the sealing target fluid O side, whereby the pressure P1 is applied on the sealing target fluid O side until the sealed state is reached. It may take some time.
Then, it is difficult to protect the main seal 21 from the pressure of the fluid O to be sealed due to the leak of the fluid until the sealed state is reached.

On the other hand, according to the above-described embodiment, the main seal is provided for a long period of time by buffering the fluid pressure of the object to be sealed and leaking the back pressure on the main seal side in a short time after the pressure is applied. It can be protected and the life of the sealing system can be extended.

The sealing system according to the present embodiment and the sealing system as a comparative example are the same except for the buffering configuration. The sealing system according to the present embodiment can be realized without changing the number of parts by the same cylinder in which the same annular groove is formed as in the comparative example. However, the present invention is not limited to this, and may be realized by cylinders having different shapes in which an annular groove different from that of the comparative example is formed.

In the above-described embodiment, a mode in which two slits facing each other across the center of the buffering are provided has been described, but the present invention is not limited to this, and the number and positions of the slits are appropriately used. It is selectable.

Further, in the above-described embodiment, the embodiment in which the lip is provided over the entire circumference of the buffering has been described, but the present invention is not limited to this, and the lip may be provided only partially. ..

Further, in the above-described embodiment, the embodiment in which the buffering is chamfered has been described, but the present invention is not limited to this, and the buffering may not be chamfered.

Further, in the above-described embodiment, the mode in which the buffering lip is in close contact with the upper and lower surfaces of the annular groove has been described, but the present invention is not limited to this, and the buffering lip is attached to the upper and lower surfaces of the annular groove. It does not have to be in close contact with. This is because if the sealing area due to the buffering lip is large, even if a fluid leak occurs, the amount of the leak is small, so the effect is small.

Further, various industrial machines such as construction machines have been exemplified as fields to which the present invention can be applied, but the present invention is not limited to this, and can be applied to various machines operated by a hydraulic cylinder.

1,101 Sealing system 2 Cylinder 3 Rod 10,20,30 Circular groove 10a Upper bottom surface 10b, 10c Side wall surface 11,111 Buffering 12,112 Body side slit 12a Lip side slit 13,113 Slope 14 Lip 15 Body part 21 Main Seal 22 Backup ring 31 Dust seal 115, 116, 117 Gap

Claims (3)

A buffer ring arranged in an annular groove provided on the inner circumference of the housing on the fluid side to be sealed with respect to the main seal that seals the annular gap between the reciprocating shaft portion and the inner circumference of the housing.
An annular body that can slide on the shaft,
A slit on the main body side provided on the surface of the body portion arranged on the fluid side to be sealed, and
A lip extending from the outer periphery of the body portion toward the fluid side to be sealed and toward the bottom surface of the annular groove is provided.
A buffer ring provided with a slit on the lip side at the tip of the lip. The buffering according to claim 1, wherein the lip can be brought into close contact with the bottom surface of the annular groove. With the main seal
A dust seal arranged in an annular groove provided on the inner circumference of the housing on the atmosphere side of the main seal, and
A sealing system comprising the buffering according to claim 1 or 2.

Images