JP2004218787A - Fixed seal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing structure capable of enduring sealing of high pressure fluid. <P>SOLUTION: A fixed seal S forming an opening channel part 3 in the direction of shaft axis by an inner lip part 1 and an outer lip part 2 is provided. This fixed seal S has small projections 20, 20 for sealing low pressure in a small triangular shape in a corner part of a rear surface 5a of a bottom wall part 5, and they come into pressure contact with an outer peripheral face 7 of a shaft and an inner peripheral face 8 of a hole by deforming plastically. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to fixed seals.
[0002]
[Prior art]
An appropriate sealing seal for sealing high-pressure gas as a fluid is hardly known, and a rubber O-ring 41 as shown in FIG. It is mounted and used in a concave circumferential groove 43 {so-called integral groove} formed integrally with 42. That is, as shown by a two-dot chain line in FIG. 7, the O-ring 41 is mounted in the concave peripheral groove 43 of the spool (shaft) 42 beyond the basic diameter end portion 44 while elastically expanding the diameter. Reference numeral 45 denotes a valve body called a housing or a body, and the O-ring 41 comes into contact with the inner peripheral surface of the hole 45a to perform a sealing action.
The reason for using such an integral groove is that, in the case of a divided groove structure, it is necessary to assemble the basic diameter end portion 44 of FIG. 7 as a separate component with a screw, a bolt, a snap ring, or the like, and This is because there is a problem such as an increase in space and an increase in the volume of valves.
[0003]
[Problems to be solved by the invention]
However, when the fluid to be sealed is a high-pressure gas of, for example, 70 MPa, there is a possibility that the rubber O-ring 41 may be blistered or excessively deformed.
In addition, in the case of a metal (metal) O-ring, as shown by a two-dot chain line in FIG. 7, the diameter cannot be expanded (stretched), and the O-ring cannot be mounted on a spool (shaft) 42 having an integrated groove structure. When the metal O-ring reciprocates with a small dimension in accordance with the increase and decrease, local wear of the hole 45a and the metal O-ring is remarkable, which is not suitable for use.
[0004]
Therefore, an object of the present invention is to provide a seal which is applicable to sealing of a high-pressure fluid as described above and has a simple and compact structure. It is another object of the present invention to provide a fixed seal that does not deform the blister or the seal, prevents external leakage of the high-pressure fluid, and has a long life.
[0005]
[Means for Solving the Problems]
The present invention provides a resin-made fixed seal in which an opening groove portion that opens in one direction of an axial center is formed by an inner lip portion that contacts an outer peripheral surface of a shaft and an outer lip portion that contacts an inner peripheral surface of a hole. In the vicinity of the other end of the bottom wall of the groove in the other direction of the axis, a low-pressure sealing small projection which is plastically deformed in the mounted state and is pressed against the outer peripheral surface of the shaft and the inner peripheral surface of the hole is provided.
[0006]
In addition, a first lip portion that is interposed between the opposed first flat surface portion and the second flat surface portion and that contacts the first flat surface portion and a second lip portion that contacts the second flat surface portion. In a resin-made fixed seal formed with an opening groove that opens in one radial direction, the first flat surface portion is plastically deformed in a mounted state near a radial other end of a bottom wall of the opening groove portion. -It has a small projection for low pressure sealing which is pressed against the second flat surface portion.
Also, the thickness of the bottom wall is set to 51% to 80% of the axial dimension, or the thickness of the bottom wall is set to 51% to 80% of the radial dimension. It is desirable.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail based on the illustrated embodiments.
1 and 2 show an embodiment of the present invention. FIG. 2 is a sectional view of a fixed seal S in a free state (unmounted state). FIG. 1 shows a fixed seal S in this free state. It is a figure explaining the positional relationship and dimensional relationship with a mounting (use) location.
[0008]
That is, the seal S is for fixing (stationary), has an inner lip portion 1 and an outer lip portion 2, and an opening groove 3 opening in one direction A of the axial center is formed by the inner and outer lip portions 1, 2. The whole is annular, and the cross-sectional shape is substantially U-shaped, and it is preferable to prevent external leakage of fluid as PTFE without filler, and in particular, creep resistance for high pressure (for example, 70 MPa) It is desirable to use a modified PTFE having excellent properties. Thus, the seal S of the present invention is a fixed part seal for high pressure fluid made of resin.
[0009]
The storage chamber portion 4 for storing the fixed seal S has a back bottom surface 6 corresponding to the back surface 5a of the bottom wall portion 5 of the opening groove portion 3 of the fixed seal S, and the opening groove portion 3 corresponds (opens). ) One axial direction A is open. In other words, the storage chamber part 4 is a space having a whole annular shape and a rectangular cross section, but is open upward in FIG.
[0010]
More specifically, in the sealing structure shown in FIG. 1, a hole 12 of a fixing member 11 such as a housing (body) of a valve, a tank, a flange, or the like, and the hole 12 is inserted into the hole 12. The storage chamber portion 4 is formed by the shaft member 14 having the step 13. The shaft member 14 has a basic diameter portion 15 and a small-diameter shaft portion 16 reduced in diameter by the step 13, and the outer diameter of the basic diameter portion 15 is slightly smaller than the inner diameter of the hole 12. The step 13 is set so as to have an orthogonal plane orthogonal to the axis L, and the above-described inner bottom surface 6 corresponds to the step 13. The small-diameter shaft portion 16 extends from the step 13 side toward the tip {the upper end in FIG. 1} with the same diameter without the small ridges. A tapered portion 17 is formed.
The fixed seal S is guided and guided by the tapered portion 17 and is smoothly fitted to the small-diameter shaft portion 16.
[0011]
In this manner, the storage chamber portion 4 is formed so as to be opened in one axial direction A by the hole portion 12 of the fixing member 11 and the shaft member 14 of the step 13 inserted into the hole portion 12. The fixed seal S can be smoothly fitted into the storage chamber 4.
[0012]
As shown in FIG. 1, with the seal S attached, the inner lip portion 1 resiliently contacts the outer peripheral surface {the shaft outer peripheral surface 7} of the small-diameter shaft portion 16 and the outer lip portion 2. Makes elastic contact with the inner peripheral surface of the hole 12 of the fixing member 11 {the inner peripheral surface 8 of the hole}.
[0013]
In FIGS. 5 and 6, and FIG. 1, the vacant chamber side in one direction A of the axial center is the high-pressure fluid chamber 18 side. S, as the opening groove 3 is expanded, the inner lip portion 1 is pressed (as indicated by the arrow F ₀ in FIG. 5) strongly Jikugaishu surface 7, the outer lip 2 into the hole inner peripheral surface 8 I pressed (as indicated by the arrow F ₀ in FIG. 5) strongly, if Takamare pressure P ₀ of the fluid chamber 18 side, with it, a self-sealing seal to press more strongly.
[0014]
However, as shown in FIG. 6, when the pressure in the fluid chamber 18 decreases (lower pressure), the inner and outer lip portions 1 and 2 contact the shaft outer peripheral surface 7 and the hole inner peripheral surface 8 as the self-sealing seal described above. The surface pressure (see arrow F ') becomes extremely low, and the sealing performance (sealing performance) is reduced. Therefore, in the fixed seal S according to the present invention, as shown in FIGS. 1 and 2, the low-pressure sealing small projections 20 and 20 are attached to the bottom wall 5 at the other end of the axial center (the direction opposite to the arrow A). It is provided in the vicinity 5b.
[0015]
In other words, in FIG. 1 and FIGS. 5 and 6, in the mounted (used) state, the low pressure sealing small projections 20, 20 are pressed against the shaft outer peripheral surface 7 and the hole inner peripheral surface 8 while being plastically deformed. As described above, for example, a small triangular mountain-shaped cross section is formed so as to protrude radially inward and radially outward. Arrow E in arrow E ₀ and in Figure 6 in FIG. 5 ', as shown in the force which the low pressure sealing small projections 20, 20 is pressed against the axial outer peripheral surface 7-hole peripheral surface 8, E ₀ and E' Are approximately the same size.
[0016]
In the embodiment shown in FIGS. 1 and 2, one low-pressure sealing small projection 20 is provided on the bottom wall 5 at the corner between the back surface 5a and the inner peripheral surface so as to project radially inward. In addition, one small-pressure sealing small protrusion 20 is provided at a corner between the back surface 5a and the outer peripheral surface so as to protrude radially outward. The cross-sectional shape of the low-pressure sealing small projection 20 may be a small triangle as shown in the drawing, a small scalene triangle inclined to the fluid chamber 18 side, or a small trapezoid or small semicircle ( (Maruyama shape) etc. are also free. Further, it is desirable that a plurality of the small protrusions 20 are arranged on the inner diameter side and the outer diameter side, respectively, to further improve the sealing property (seal property) at low pressure.
[0017]
Next, the thickness T (measured in the axial direction) of the bottom wall 5 is 51% to 80% of the dimension H in the seal axial direction, which is significantly large (compared to the conventional U-shaped seal). Set to. Thereby, high-pressure gas permeation can be reduced.
[0018]
In the embodiment shown in FIG. 1, the storage chamber portion 4 is “open” in one direction A of the axial center when the small ridge (small projection) on which the inner lip portion 1 is hooked is the axis. It means that the small ridge (small protrusion) that does not exist on the outer peripheral surface 7 and the outer lip portion 2 is hooked on does not exist on the inner peripheral surface 8 of the hole. In other words, the opening groove 3 of the seal S directly faces the high-pressure fluid chamber 18.
[0019]
Next, FIGS. 3 and 4 show another embodiment of the present invention. FIG. 4 is a sectional view of the fixed seal S in a free state (unmounted state), and FIG. 3 is a view for explaining a positional relationship and a dimensional relationship between the fixed seal S shown in the free state and a mounting (use) location. FIG. The seal S is also fixed (stationary), is made of the same material, and is interposed between the first flat surface portion 21 and the second flat surface portion 22 which are relatively opposed to each other. The cross-sectional shape is substantially U-shaped as in the above-described embodiment, but the direction of the opening groove portion 3 is a radial (inside / outside) one direction R (the drawing shows a case where the direction is a radial inward direction). Suitable for
[0020]
The first lip portion 1a contacts the first flat surface portion 21, and the second lip portion 2a contacts the second flat surface portion 22. The opening groove portion 3 opens in one radial direction R, and faces inward in the radial direction in FIG. 3. The inner peripheral side of the seal S is the high-pressure fluid chamber 18.
Then, the first and second flat surface portions 21 and 22 are plastically deformed in the mounted state in the vicinity 5c of the edge of the bottom wall portion 5 of the opening groove portion 3 in the other radial direction {the direction opposite to the arrow R}. The small projections 20 and 20 for low pressure sealing which are pressed into contact with are provided.
[0021]
The storage chamber portion 4 for storing the fixed seal S has a rear bottom surface 6 corresponding to the back surface (outer peripheral surface) 5a of the bottom wall portion 5 of the seal S, and a radial direction R corresponding to the opening groove 3 of the seal S. Is open. That is, the storage chamber portion 4 is a space having a generally annular shape and a rectangular cross section, and is open in the inner diameter direction (radial inward direction) as shown in FIG.
Specifically, the fixing member 11a such as a housing (body), a tank or a flange of the fluid device has a shallow (circular) recess 23, and the bottom surface of the shallow recess 23 corresponds to the first flat surface portion 21. I do.
[0022]
A lid member 24 such as a flange or a casing (of another fluid device) is fixed to the fixing member 11a by a fixing tool or a connecting tool (not shown). A protruding portion 25 is formed so as to be fitted to face the surface 23a, and a distal end surface of the protruding portion 25 corresponds to the second flat surface portion 22. And, being opened in the radial inward direction R means that even if the seal S is reduced in diameter, there are no small projections, small ridges or walls on which the first and second lip portions 1a, 2a are hooked. Say.
[0023]
In FIG. 4, a relational expression of 0.51 × H ′ ≦ T ≦ 0.80 × H ′ is established between the thickness dimension T of the bottom wall 5 and the seal radial dimension H ′. Set the dimensions so that The reason is the same as in the above-described embodiment of FIGS.
[0024]
In the embodiment shown in FIGS. 3 and 4, the first lip portion 1a comes into contact with the first flat surface portion 21 and the second lip portion 2a comes into contact with the second flat surface portion 22 in a resilient manner. ing. When pressure is applied from the high-pressure fluid chamber 18 side, the first and second lip portions 1a and 2a are opened legs so that the opening groove portion 3 expands (similar to that already described with reference to FIG. 5). The flat surface fixed seal S also acts as a seal.
[0025]
However, when the pressure in the fluid chamber 18 decreases, the surface pressure at which the first and second lip portions 1a and 2a come into contact as a self-sealing seal decreases extremely, so that the sealing performance (sealing performance) at low pressure deteriorates. However, since the low-pressure sealing small projections 20 and 20 are strongly pressed against the first and second flat surface portions 21 and 22, external leakage occurs even when the pressure is reduced (at low pressure). Absent.
[0026]
In FIGS. 3 and 4, the small projections 20 having a small triangular cross section project from the corner near the edge 5c in both axial directions, and the first projections 20 and 20 are plastically deformed in the mounted state. Pressing against the second flat surface portions 21 and 22. The cross-sectional shape of the low-pressure sealing small projection 20 may be a small triangle, a trapezoidal shape, a small semicircle (circular mountain shape), or the like, in addition to the small triangle shown in FIG. Two or more strips may be arranged concentrically.
[0027]
Although not shown, the inner and outer radial directions are reversed from those in FIGS. 3 and 4 so that the opening groove 3 is directed radially outward (outer radial direction) so that high pressure acts from the outer peripheral side. May be configured. In this case, the storage chamber portion 4 has a shape in which the inner bottom surface is disposed on the inner diameter side and the outer diameter side is open.
[0028]
In each of the embodiments of the present invention, a spring is provided in the opening groove 3 (not shown) so that the inner and outer lip portions 1 and 2 or the first and second lip portions 1a and 2a are resiliently provided. You are free to increase your power. However, as shown in FIGS. 1 to 6, omitting the spring has the advantage that the number of components is minimized, the structure is simplified, and the cost can be reduced.
[0029]
Also, as shown in FIG. 1 or FIG. 3, small projections (small protrusions) are formed so that the inner and outer lip portions 1 and 2 or the first and second lip portions 1a and 2a can be hooked. It is omitted on the side that opens to the 18 side, and has the advantage that the shape and structure of the shaft member 14 or the fixing member 11a and the like can be simplified, and that the work of mounting (assembling) the seal S becomes easy. There is.
[0030]
【The invention's effect】
The present invention has the following significant effects by the above configuration.
(According to claim 1) At the time of high pressure operation, the self-sealing action of the inner and outer lip portions 1 and 2 exerts a sealing property (sealability). Sealability (sealability) can be maintained.
In addition, in many cases, the metal spring mounted in the opening groove portion 3 can be omitted, so that the number of parts can be reduced, the structure can be simplified, and manufacturing can be facilitated.
[0031]
(According to claim 2) At the time of high pressure, the self-sealing action of the first and second lip portions 1a, 2a exerts a sealing property (sealing property). On the other hand, at the time of low pressure, the low pressure sealing small projections 20, By virtue of 20, the sealing property (sealability) can be reliably maintained.
In addition, in many cases, the metal spring mounted in the opening groove portion 3 can be omitted, so that the number of parts can be reduced, the structure can be simplified, and manufacturing can be facilitated.
[0032]
According to the third and fourth aspects, permeation of a fluid such as a high-pressure gas can be prevented.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an embodiment of the present invention and illustrating a positional relationship and a dimensional relationship of components.
FIG. 2 is a sectional view of a seal.
FIG. 3 is a view showing another embodiment and explaining a positional relationship and a dimensional relationship of components.
FIG. 4 is a sectional view of a seal.
FIG. 5 is an operation explanatory diagram at the time of high pressure.
FIG. 6 is an explanatory diagram of an operation at a low pressure.
FIG. 7 is an explanatory sectional view showing a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Inner lip part 1a 1st lip part 2 Outer lip part 2a 2nd lip part 3 Opening groove part 4 Storage room part 5 Bottom wall part 5a Back surface 5b Near end part 5c Near end edge 6 Back bottom surface 7 Shaft outer peripheral surface 8 Hole inner periphery Surface 20 Small protrusion 21 for low-pressure sealing First flat surface portion 22 Second flat surface portion A One-way H, H 'seal axis direction dimension R One-way radial direction S Fixed seal T Thickness dimension

Claims (4)

An opening groove (3) opening in one direction (A) of the shaft center by an inner lip (1) contacting the shaft outer peripheral surface (7) and an outer lip (2) contacting the hole inner peripheral surface (8). In the fixed seal made of resin, the outer peripheral surface of the shaft is plastically deformed in the mounted state near the end (5b) of the bottom wall (5) of the opening groove (3) in the other direction of the axis. (7) A fixed seal characterized by comprising small projections (20) and (20) for low pressure sealing which are pressed against the inner peripheral surface (8) of the hole. A first lip portion (1a) interposed between the opposed first flat surface portion (21) and the second flat surface portion (22) and in contact with the first flat surface portion (21); In a resin-made fixed seal having an opening groove (3) opened in one radial direction (R) by the second lip portion (2a) in contact with the surface portion (22), the opening groove (3) is formed. A small low-pressure sealing small protrusion that presses against the first flat surface portion (21) and the second flat surface portion (22) while being plastically deformed in a mounted state in the vicinity (5c) of the edge in the radial other direction of the bottom wall portion (5). (20) A fixed seal comprising (20). The fixed seal according to claim 1, wherein a thickness (T) of the bottom wall (5) is set to 51% to 80% of an axial dimension (H). 3. The fixed seal according to claim 2, wherein the thickness (T) of the bottom wall (5) is set to 51% to 80% of the radial dimension (H ').

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