JP2004169766A - Sealing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing device small in sliding resistance for suppressing eccentricity in relative movement of two members. <P>SOLUTION: A packing 1 is disposed in an annuler groove 11 formed in a piston 10 reciprocating in an axial direction to allow sealing of a clearance between the piston 11 and a housing 20. The packing 1 comprises: an outer peripheral lip 2 in press-contact with the housing 20; an inner peripheral lip 3 in press-contact with the piston 10; and projections 6, 7 disposed to the outer peripheral lip 2 and the inner peripheral lip 3, projecting into a groove part between the outer peripheral lip 2 and the inner peripheral lip 3 to control a distance between the outer peripheral lip 2 and the inner peripheral lip 3. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a technique relating to a sealing device such as a packing, and can be suitably used for a valve having a piston structure operated by a fluid such as water or air.
[0002]
[Prior art]
A packing for a valve having a piston structure is required to have low sliding resistance. For this reason, a packing having no crushing allowance and a thin lip thickness, that is, a packing having a small expansion force is used.
[0003]
As a conventional packing used for such a purpose, there is a packing shown in FIGS. 7 is a half sectional view of a conventional packing, FIG. 8 is a half sectional view showing a state where the conventional packing is mounted on a piston, and FIG. 9 is a sectional view showing a state of the conventional packing when the piston is eccentric. FIG.
[0004]
The packing 101 is formed of an annular rubber-like elastic body, and is disposed in an annular groove 111 provided in a piston 110 that reciprocates.
[0005]
Further, the packing 101 includes an outer peripheral lip 102 that extends toward the sealing target side I and is in close contact with the inner wall 121 of the tube 120 and an inner peripheral lip 103 that is in close contact with the groove bottom 112 of the annular groove 111. A substantially U-shaped groove 104 is provided between the peripheral lip 103 and the peripheral lip 103.
[0006]
When the width of the outer peripheral lip 102 and the inner peripheral lip 103 is W in a state where the piston is not attached to the annular groove 111, the piston is in a normal position, that is, the bottom of the tube inner wall 121 and the groove bottom of the annular groove 111 when there is no eccentricity. Assuming that the distance from the outer peripheral lip 102 is b, the distal end portion 105 of the outer peripheral lip 102 is provided with the interference allowance Wb = a. Therefore, this interference allows the seal between the piston 110 and the tube 120 to be maintained when the piston is in the normal position without eccentricity.
[0007]
However, as described above, since the packing used for the valve having the piston structure has a small expansion force, when the packing 101 is arranged on the piston 110 and mounted on the tube 120, the packing is not necessarily connected to the center of the tube 120. Does not always coincide with the center of the axis. Therefore, when the piston 110 is eccentrically mounted on the tube 120, a gap is generated between the piston 110 and the tube 120 when the amount of eccentricity c exceeds a certain amount as shown in FIG. Can not do it.
[0008]
In order to solve such a problem, Patent Document 1 discloses a seal for hydraulic equipment having a substantially U-shaped cross-sectional shape, and the sum of the widths of the tip ends of two seal lips is determined between the piston and the cylinder. A configuration in which the sealing effect is enhanced by increasing the width of the sealing groove is disclosed. That is, when the seal is mounted in the seal groove, the two seal lips are elastically deformed in the width direction and are mounted in the seal groove, so that the seal lip is firmly pressed against the surface to be sealed of the two members, and Even when the pressure is low, a high sealing effect can be obtained.
[0009]
[Patent Document 1]
JP 2002-147614 A
[Problems to be solved by the invention]
However, the configuration described in Patent Document 1 has the following problems.
[0011]
In other words, when eccentricity occurs when the piston is attached to the cylinder, the inner ends of the two seal lips come into close contact with each other and act to return the piston to a normal position. If there is a certain effect.
[0012]
However, even when the piston is inserted in a normal position, the inner ends of the two seal lips are always in close contact with each other, so that the sliding resistance increases and the operability of the valve increases. Will drop.
[0013]
SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the related art, and an object of the present invention is to provide a sealing device that suppresses eccentricity when two members relatively move and has low sliding resistance. Is to do.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention,
A sealing device that is disposed in an annular groove provided in a movable member that reciprocates in an axial direction and that can seal a gap between the movable member and a housing provided coaxially with the movable member,
A first seal portion pressed against the housing;
A second seal portion pressed against the movable member;
The first seal portion and / or the second seal portion is provided on the first seal portion and / or the second seal portion, and protrudes into a groove between the first seal portion and the second seal portion, and a distance between the first seal portion and the second seal portion. And a protrusion that regulates
[0015]
In another aspect,
A sealing device that is disposed in an annular groove provided in a movable member that reciprocates in an axial direction and that can seal a gap between the movable member and a housing provided coaxially with the movable member,
A first seal portion pressed against the housing;
A second seal portion pressed against the movable member;
A first protrusion provided on the first seal portion and projecting into a groove between the first seal portion and the second seal portion;
A second protrusion provided on the second seal portion and protruding into the groove portion facing the first protrusion portion;
In the state where the movable member is inserted into the housing such that the axis center of the movable member substantially coincides with the center of the housing, a gap is formed between the first protrusion and the second protrusion. And
When the amount of eccentricity of the center of the axis of the movable member reaches a certain amount, the first protrusion and the second protrusion come into contact with each other, and regulate an interval between the first seal portion and the second seal portion. It is characterized.
[0016]
Alternatively, in another aspect,
A sealing device that is disposed in an annular groove provided in a movable member that reciprocates in an axial direction and that can seal a gap between the movable member and a housing provided coaxially with the movable member,
A first seal portion pressed against the housing;
A second seal portion pressed against the movable member;
An annular projection provided on the first seal portion or the second seal portion and projecting into a groove between the first seal portion and the second seal portion;
In a state where the movable member is inserted into the housing such that the axis center of the movable member substantially coincides with the center of the housing, the movable member is located between the protrusion and the second seal portion or the first seal portion. A gap is formed,
When the amount of eccentricity of the shaft center of the movable member reaches a certain amount, the protrusion contacts the first seal portion or the second seal portion, and a distance between the first seal portion and the second seal portion. Is regulated.
[0017]
According to the configuration described above, even if the movable member is inserted into the housing in an eccentric state, the deformation of the seal portion due to the eccentricity is regulated by the projection, so that the movable member can be moved without increasing the sliding resistance. Eccentricity with respect to the housing can be suppressed.
[0018]
In the state where the movable member is inserted into the housing such that the axis center of the movable member is substantially coincident with the center of the housing, the amount of radial deformation of the first seal portion is a, Let b be the gap between the bottom and the inner wall of the housing,
When the radial thickness of the first protrusion provided on the first seal portion is d, and the radial thickness of the second protrusion provided on the second seal portion is e,
a> b− (d + e) ≧ 0
It is preferable to have the following relationship.
[0019]
According to this configuration, the gap b between the groove bottom of the annular groove and the inner wall of the housing without eccentricity is larger than the sum (d + e) of the thickness d of the first protrusion and the thickness e of the second protrusion. Therefore, in the non-eccentric state, the projections do not come into contact with each other, and the outer peripheral lip is not pressed against the inner wall of the housing by the repulsive force, so that the sliding resistance does not increase.
[0020]
In the state where the movable member is inserted into the housing such that the axis center of the movable member is substantially coincident with the center of the housing, the amount of radial deformation of the first seal portion is a, Let b be the gap between the bottom and the inner wall of the housing,
The radial thickness of the protrusion provided on the first seal portion or the second seal portion is f, and the radial thickness of the second seal portion or the first seal portion facing the protrusion is f. g
a> b− (f + g) ≧ 0
It is preferable to have the following relationship.
[0021]
According to this configuration, the gap b between the groove bottom of the annular groove and the inner wall of the housing in a state without eccentricity is equal to the sum (f + g) of the thickness f of the projection and the thickness g of the first seal portion or the second seal portion. ), The projections do not come into contact with each other when they are not eccentric, and the outer peripheral lip is not pressed against the inner wall of the housing by the repulsive force, so that the sliding resistance does not increase.
[0022]
It is preferable that the protrusion is provided in the groove continuously in an annular manner.
[0023]
According to this configuration, the protrusion does not have a complicated shape, and the packing is easily manufactured.
[0024]
It is preferable that the protrusions are provided at equal intervals in the groove.
[0025]
According to this configuration, since the protrusions are provided at equal intervals, a force acting in the center direction of the housing is generated, and the movable member in an eccentric state gradually moves toward the center of the housing and slides. Resistance also decreases.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention thereto unless otherwise specified. Absent.
[0027]
(First Embodiment)
A packing according to a first embodiment of the present invention will be described with reference to FIGS. 1 is a half sectional view of the packing according to the present embodiment, FIG. 2 is an overall top view of the packing of FIG. 1, and FIG. 3 is a half view showing a state where the packing according to the present embodiment is mounted on a piston. FIG. 4 is a sectional view showing a state of the packing according to the present embodiment when the piston is eccentric.
[0028]
The packing 1 is arranged in an annular groove 11 provided in a reciprocating piston 10 shown in FIG.
[0029]
The packing 1 includes an outer peripheral lip 2 that extends toward the sealing target side I and is in close contact with the inner wall 21 of the tube 20 and an inner peripheral lip 3 that is in close contact with the groove bottom 12 of the annular groove 11. A substantially U-shaped concave groove portion 4 is provided between the peripheral lip 3 and the peripheral lip 3.
[0030]
The packing 1 has a width W between the outer peripheral lip 2 and the inner peripheral lip 3 when not installed in the annular groove 11, and a groove between the tube inner wall 21 and the annular groove 11 at a position where the piston is normal, that is, at a position where there is no eccentricity. When the distance from the bottom 12 is b, the interference margin of Wb = a is provided at the tip 5 of the outer peripheral lip 2.
[0031]
A projection 6 is provided partially on the U groove side of the outer lip 2, and a projection 7 is provided on the U groove side of the inner lip 3 at a position facing the projection 6.
[0032]
The packing 1 is made of a rubber-like elastic body, and suitably employs, for example, NBR (nitrile rubber), EPDM (ethylene propylene rubber), FKM (fluoro rubber), AU (urethane rubber), or the like. be able to.
[0033]
Next, the configuration of the protrusions 6 and 7 will be described in more detail below.
[0034]
When the piston 6 is at a normal position without eccentricity, the projection 6 and the projection 7 keep a state with a gap without contacting each other. This is because when the piston is in the normal position, no external force is required to move the position of the center axis of the piston, and therefore, it is preferable that no crush occurs between the protrusion 6 and the protrusion 7. Because.
[0035]
That is, the outer peripheral lip thickness d of the projection 6 and the inner peripheral lip thickness e of the projection 7 at the place where the projection 6 and the projection 7 are in contact with each other,
b− (d + e) ≧ 0
It is good to set so that. Here, b is the distance between the tube inner wall 21 and the groove bottom 12 of the annular groove 11 when the piston is in a normal position, that is, without eccentricity. If b− (d + e) <0 is set, the packing 1 is always inserted into the annular groove 11, and when the packing 1 is inserted into the tube 20, crushing always occurs between the protrusion 6 and the protrusion 7. Therefore, the sliding resistance is always high, and the operability of the valve is reduced.
[0036]
On the other hand, when the piston 10 is inserted into the tube 20 in an eccentric state, an external force for moving the piston 10 to the center of the tube 20 is required. Therefore, the outer peripheral lip thickness d of the projection 6 and the inner peripheral lip thickness e of the projection 7 are
b− (d + e) <a
It is good to set so that. Here, a is the size of the interference allowance of the outer peripheral lip 2.
[0037]
The reason for setting as described above is that the maximum value of the eccentricity c in the present embodiment is b− (d + e) even when the projection does not crush, so that the eccentricity c is smaller than the interference a. 4, no gap is generated at any position on the peripheral edge, and high sealing performance can be maintained.
[0038]
When b− (d + e)> a is set, a gap is formed between the distal end portion 5 of the outer peripheral lip 2 and the inner wall 21 of the tube 20 even if the eccentric amount is such that the projection is not crushed. Although it may occur, the center axis of the piston 10 at the time of eccentricity is not moved to the center position of the tube 20 due to the repulsive force of the crushing, and the sealing property between the piston 10 and the tube 20 can be satisfied. Gone.
[0039]
From the above, in the present embodiment, the outer peripheral lip thickness d of the projection 6 and the inner peripheral lip thickness e of the projection 7 are defined as:
a> b− (d + e) ≧ 0
It is particularly preferable to set the following.
[0040]
According to this configuration, when the piston 10 is inserted in a state where the piston 10 is not eccentric with respect to the tube 20 or in a state where the amount of eccentricity is small, the protrusion does not crush, so that the sliding resistance does not increase and the operation of the valve is not performed. Is performed smoothly. On the other hand, when the piston 10 is inserted in an eccentric state with respect to the tube 20, the protrusion is crushed, and the eccentricity of the piston 10 is suppressed by the repulsive force of the protrusion. The central axis of the piston 10 is corrected to the position. Therefore, leakage due to the gap can be prevented, and the sliding resistance can be reduced while satisfying the sealing property.
[0041]
In addition, by making the protrusions 6 convex, the rigidity of the outer peripheral lip 2 can be reduced, and the sliding resistance between the outer peripheral lip 2 and the tube inner wall 21 can be reduced.
[0042]
Further, either the protrusion 6 or the protrusion 7 may be provided on the outer peripheral lip 2 or the inner peripheral lip 3 continuously in an annular manner. By providing the ring-shaped portion continuously, the protrusion does not have a complicated shape, and the packing 1 is easily manufactured. More preferably, the annular continuous projection is provided on the inner peripheral lip 3 rather than the outer peripheral lip 2. According to this configuration, it is possible to prevent the rigidity from increasing due to the increase in the thickness of the outer peripheral lip, and to suppress the sliding resistance between the outer peripheral lip 2 and the inner wall 21 of the tube.
[0043]
(Second embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a half sectional view of the packing according to the present embodiment, and FIG. 6 is an overall top view of the packing of FIG. Note that the same or corresponding components as those of the first embodiment are denoted by the same reference numerals, and detailed description is omitted.
[0044]
The feature of the present embodiment is the shape of the projection 8 provided in the groove 4, which will be described in detail below.
[0045]
When there is no eccentricity and the piston is at a normal position, the projection 8 keeps a gap without contacting each other. This is because, when the piston is in the normal position, no external force is required to move the position of the center axis of the piston, so that no crush occurs between the projection 8 and the inner peripheral lip 3. This is because it is preferable.
[0046]
That is, the outer peripheral lip thickness f and the inner peripheral lip thickness g of the projection 8 at the place where the projection 8 contacts the inner peripheral lip 3
b− (f + g) ≧ 0
It is good to set so that. If b− (f + g) <0 is set, the packing 1 is always inserted between the projection 8 and the inner peripheral lip 3 when the packing 1 is inserted into the mounting groove 11 and inserted into the tube 20. Therefore, the sliding resistance is always high, and the operability of the valve is reduced.
[0047]
On the other hand, when the piston 10 is inserted into the tube 20 in an eccentric state, an external force for moving the piston 10 to the center of the tube 20 is required. Therefore, the outer peripheral lip thickness f of the projection 8 and the inner peripheral lip thickness g of the inner peripheral lip 3
b− (f + g) <a
It is good to set so that.
[0048]
The reason for setting as described above is that the maximum value of the eccentricity c in the present embodiment is b− (f + g) even when the projection does not crush, so that the eccentricity c is smaller than the interference a. No gap is generated anywhere on the peripheral edge, and high sealing performance can be maintained.
[0049]
If b− (f + g)> a is set, a gap is formed between the distal end portion 5 of the outer lip 2 and the inner wall 21 of the tube 20 even if the eccentric amount is such that the projection is not crushed. Although it may occur, the center axis of the piston 10 at the time of eccentricity is not moved to the center position of the tube 20 due to the repulsive force of the crushing, and the sealing property between the piston 10 and the tube 20 can be satisfied. Gone.
[0050]
From the above, in the present embodiment, the outer peripheral lip thickness f of the projection 8 and the inner peripheral lip thickness g of the inner peripheral lip 3 are defined as:
a> b− (f + g) ≧ 0
It is particularly preferable to set the following. According to this configuration, when the piston 10 is not eccentric with respect to the tube 20 or is inserted with a small amount of eccentricity, the protrusion does not crush, so that the sliding resistance does not increase and the operation of the valve does not occur. Is performed smoothly.
[0051]
On the other hand, when the piston 10 is inserted in an eccentric state with respect to the tube 20, the protrusion is crushed, and the eccentricity of the piston 10 is suppressed by the repulsive force of the protrusion. The central axis of the piston 10 is corrected to the position. Therefore, leakage due to the gap can be prevented, and the sliding resistance can be reduced while satisfying the sealing property.
[0052]
In particular, in the present embodiment, the protrusion 8 is formed such that the width of the gap h between the protrusion 8 and the inner peripheral lip 3 becomes constant or narrow toward the groove bottom of the groove 4, so that injection molding is performed. It can be more easily manufactured with a press die or the like.
[0053]
In the present embodiment, the configuration in which the protrusion 8 is provided on the outer lip 2 has been described in detail, but more preferably, the protrusion 8 is provided on the inner lip 3. Thereby, the rigidity of the outer peripheral lip does not increase, and the sliding resistance between the outer peripheral lip 2 and the inner wall 21 of the tube can be suppressed low.
[0054]
【The invention's effect】
As described above, in a state where there is no eccentricity, by providing the protrusions so that a gap is formed between the outer peripheral lip and the inner peripheral lip of the packing, the sliding resistance when the two members relatively move is reduced. In addition, since the distance between the outer peripheral lip and the inner peripheral lip is restricted by the projection, eccentricity can be suppressed, and sealing performance can be ensured.
[Brief description of the drawings]
FIG. 1 is a half sectional view of an AA part of a packing according to a first embodiment.
FIG. 2 is an overall top view from the direction B of the packing according to the first embodiment.
FIG. 3 is a half sectional view showing a state in which the packing according to the first embodiment is mounted on a piston.
FIG. 4 is a cross-sectional view showing a state of the packing according to the first embodiment when the piston is eccentric.
FIG. 5 is a half sectional view of a DD section of the packing according to the second embodiment.
FIG. 6 is an overall top view of a packing according to a second embodiment, as viewed from a direction E.
FIG. 7 is a half sectional view of a conventional packing.
FIG. 8 is a half sectional view showing a state in which a conventional packing is mounted on a piston.
FIG. 9 is a sectional view showing a state of a conventional packing when a piston is eccentric.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 packing 2 outer lip 3 inner lip 4 groove 5 tip 6, 7, 8 protrusion 10 piston 11 annular groove 12 groove bottom 20 tube 21 tube inner wall 101 packing 102 outer lip 103 inner lip 104 groove 105 tip 110 piston 111 annular groove 112 groove bottom 120 tube 121 tube inner wall a interference allowance d, f outer lip thickness e, g inner lip thickness

Claims (9)

A sealing device that is disposed in an annular groove provided in a movable member that reciprocates in an axial direction and that can seal a gap between the movable member and a housing provided coaxially with the movable member,
A first seal portion pressed against the housing;
A second seal portion pressed against the movable member;
The first seal portion and / or the second seal portion is provided on the first seal portion and / or the second seal portion, and protrudes into a groove between the first seal portion and the second seal portion, and a distance between the first seal portion and the second seal portion. And a projection that regulates the pressure. A sealing device that is disposed in an annular groove provided in a movable member that reciprocates in an axial direction and that can seal a gap between the movable member and a housing provided coaxially with the movable member,
A first seal portion pressed against the housing;
A second seal portion pressed against the movable member;
A first protrusion provided on the first seal portion and projecting into a groove between the first seal portion and the second seal portion;
A second protrusion provided on the second seal portion and protruding into the groove portion facing the first protrusion portion;
In the state where the movable member is inserted into the housing such that the axis center of the movable member substantially coincides with the center of the housing, a gap is formed between the first protrusion and the second protrusion. And
When the amount of eccentricity of the center of the axis of the movable member reaches a certain amount, the first protrusion and the second protrusion come into contact with each other, and regulate an interval between the first seal portion and the second seal portion. A sealing device. In the state where the movable member is inserted into the housing such that the axis center of the movable member is substantially coincident with the center of the housing, the amount of radial deformation of the first seal portion is a, Let b be the gap between the bottom and the inner wall of the housing,
When the radial thickness of the first protrusion provided on the first seal portion is d, and the radial thickness of the second protrusion provided on the second seal portion is e,
a> b− (d + e) ≧ 0
3. The sealing device according to claim 2, wherein: 4. The sealing device according to claim 2, wherein the first protrusion or the second protrusion is provided in the groove continuously in an annular manner. 5. The sealing device according to claim 2, wherein the first protrusion or the second protrusion is provided at equal intervals in the groove. A sealing device that is disposed in an annular groove provided in a movable member that reciprocates in an axial direction and that can seal a gap between the movable member and a housing provided coaxially with the movable member,
A first seal portion pressed against the housing;
A second seal portion pressed against the movable member;
An annular projection provided on the first seal portion or the second seal portion and projecting into a groove between the first seal portion and the second seal portion;
In a state where the movable member is inserted into the housing such that the axis center of the movable member substantially coincides with the center of the housing, the movable member is located between the protrusion and the second seal portion or the first seal portion. A gap is formed,
When the amount of eccentricity of the shaft center of the movable member reaches a certain amount, the protrusion contacts the first seal portion or the second seal portion, and a distance between the first seal portion and the second seal portion. A sealing device characterized by regulating the following. In the state where the movable member is inserted into the housing such that the axis center of the movable member is substantially coincident with the center of the housing, the amount of radial deformation of the first seal portion is a, Let b be the gap between the bottom and the inner wall of the housing,
The radial thickness of the protrusion provided on the first seal portion or the second seal portion is f, and the radial thickness of the second seal portion or the first seal portion facing the protrusion is f. g
a> b− (f + g) ≧ 0
The sealing device according to claim 6, wherein the sealing device has the following relationship. The sealing device according to claim 6, wherein the protrusion is provided in the groove continuously in an annular manner. The sealing device according to claim 6, wherein the protrusions are provided at equal intervals in the groove.

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