JP4396850B2 - Packing - Google Patents

Description

  The present invention relates to a packing which is a kind of sealing device, and more particularly, a reciprocating or rotating ring which is mounted on one of two members facing each other and is slidably in close contact with the other member. It relates to a cylindrical packing. The packing of the present invention is used, for example, as an X-ring that seals a reciprocating part of a carbon dioxide gas valve.

  Conventionally, packings with various cross-sectional shapes have been used as reciprocating or rotating ring-shaped packings. When low sliding of sliding parts (reduction of sliding resistance) is required, Since the ring is not twisted and the frictional characteristics of the sliding part are good, an X-ring having an X-shaped cross section is often used.

  As shown in FIG. 3, the conventional X-ring 51 is generally of a cross-sectional shape in which the tip end portion of the seal lip 52 is rounded, but the lip shape having such a round shape is used. Since the lip reaction force generated at the time of compression is not yet sufficiently reduced, there is a limit to the reduction in sliding, and thus a lip shape that can realize further reduction in sliding is desired.

  Conventionally, as shown in FIG. 4, linear chamfers 62 are formed at both axial ends of the inner peripheral surface and the outer peripheral surface, and circular portions are formed at the axial intermediate portions of the inner peripheral surface and the outer peripheral surface. An arc-shaped concave groove 63 is formed to form two substantially triangular chevron lips 64 on the inner and outer peripheral surfaces, respectively, and a first angle α that forms the axis of the chamfer 62 is 32 to 42 degrees. And an X ring 61 is proposed in which the second angle β between the both ends of the concave groove 63 and the axis is set to 41 to 51 degrees (Patent Document 1 below) This prior art was devised for the purpose of improving the sealing performance and is not intended to reduce the sliding as in the present invention, and is related to the magnitude of the lip angle with the present invention. Are set differently (in this prior art, the lip angle Contrary to the present invention, the degree relationship is set to α <β.

No. 2547035 Utility Model Registration Gazette

  An object of this invention is to provide the packing which can implement | achieve further low sliding of a lip | sliding part in view of the above point.

In order to achieve the above object, a packing according to claim 1 of the present invention is a reciprocating or rotating ring shape that is mounted on one of two members facing each other and is slidably in close contact with the other member. In the packing, a chamfered portion having a linear cross section is provided at each axial end of the packing at least on the sliding surface side, a tapered portion having a linear cross section is provided on the axially inner side of the chamfered portion, and the chamfered portion is the center. An angle formed with the axis is α, and an angle formed between the tapered portion and the central axis is β1,
α> β1
A sharp lip end that satisfies the above relationship is provided between the chamfered portion and the tapered portion, and a groove for a grease reservoir having a circular arc shape is provided between the pair of tapered portions in the axial direction, and the tapered portion is a central axis. The angle formed by β1 and the angle formed by the groove with the central axis at the axial end thereof is β2.
β1 <β2
An inner step portion that satisfies the above relationship is provided between the tapered portion and the groove portion inside the sharp lip end, and an angle α between the chamfered portion and the central axis is 40 to 50 degrees, and the tapered portion is the central axis. The angle β1 is 15 to 25 degrees, and the angle β2 the groove is formed with the central axis at the axial end is 35 to 45 degrees .

  The present invention has the following effects.

  That is, in the packing according to the first aspect of the present invention having the above-described configuration, the apex lip ends satisfying the relationship of “α> β1” are formed at both axial ends of the sliding surface. Therefore, the axial contact width of the seal lip with respect to the mating material can be set short, and the volume of the lip end is made smaller than that of the conventional seal lip, so the reaction force generated during compression can be reduced. Can be reduced.

  In addition, according to the above configuration, an annular recess is formed between the pair of axial lip ends in the axial direction, and this annular recess acts as a grease reservoir in which grease is sealed. When used in the above, the relationship of “α> β1” causes the grease to flow out from the recess moderately, whereby an oil film can always be formed on the sliding portion. On the other hand, in the prior art disclosed in the above-mentioned Patent Document 1, since the relationship of “α <β” is opposite to the present invention, the action of the grease flowing out gradually from the concave portion does not occur, Even if an oil film is formed in advance, grease is sucked toward the recess, and it becomes difficult to maintain the oil film. Therefore, the grease exudation phenomenon as in the present invention does not occur.

  Therefore, in combination with these events, it is possible to realize a low sliding of the packing sliding portion, and it is possible to realize a long life by improving the wear resistance.

In addition, in the packing according to claim 1 of the present invention having the above-described configuration, the inner stepped portions satisfying the relationship of “β1 <β2” on the inner sides of the pair of cusp-like lip ends in the axial direction. Therefore, during compression, the packing does not contact the mating material (even if the taper portion contacts the surface, the inner surface of the groove portion is in accordance with the relationship of “β1 <β2”. Therefore, the reaction force generated can be further reduced, and at this time, a grease pool can still be secured by the groove portion that does not contact the mating material.

  Therefore, in combination with these events, it is possible to realize further lower sliding of the packing sliding portion, and it is possible to realize longer life by improving the wear resistance.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a cross section of a packing 1 according to an embodiment of the present invention. The packing 1 according to this embodiment is used as a reciprocating packing in a reciprocating portion of a carbon dioxide gas valve, and is configured as follows.

  That is, the packing 1 is formed in an annular shape by a predetermined rubber-like elastic body such as EPDM rubber, and has annular recesses in the central portions of its inner peripheral surface, outer peripheral surface, and both axial side surfaces based on a rectangular cross section. 2 and having seal lips 3 at both ends in the axial direction of the inner peripheral surface and the outer peripheral surface, respectively, are formed in an X-shaped cross section. Therefore, the packing 1 may be referred to as an X ring because of its cross-sectional shape.

Respectively within axial end portions of the circumferential surface and axial end portions of the outer peripheral surface of the opposite side forming the sliding surface of the packing 1, section straight chamfered portion 4 having a predetermined axial width x ₁ is provided together are, respectively axially inward of the chamfered portion 4, sectional linear tapered portion 5 having a predetermined axial width x ₂ is provided by the chamfered portion 4 and taper portions 5 intersect each A pointed lip end 6 is formed. The angle relationship between the chamfered portion 4 and the central axis of the packing 1 is α, and the angle between the tapered portion 5 and the central axis of the packing 1 is β1.
α> β1... is set so as to satisfy the equation (1).

  The above “pointed shape” is a pointed corner as defined in the meaning of the word, but the formation of roundness that is unavoidable for molding or that is functionally effective is allowed and included, and the pointed angle is illustrated. Thus, the case where the angle formed is an obtuse angle is also included.

Further, each of the axially between the pair of tapered portions 5, and an arc-shaped cross section of the groove 7 having a predetermined axial width x ₃ is provided by the tapered part 5 and the groove 7 intersect each In addition, a convex inner stepped portion 8 is provided due to the difference in the inclination angle between the two 5 and 7. The angle relationship between the taper portion 5 and the center axis of the packing 1 is β1, and the angle between both axial ends of the groove portion 7 and the center axis of the packing 1 is β2, respectively.
β1 <β2... (2) is set to be satisfied.

  In addition, the relationship between the sizes of the respective parts is set as follows.

That, x ₁ the axial width of the chamfered portion _4, the axial width x ₂ of the tapered portion _5, the axial width of the groove 7 as x _3,
x ₂ <x ₁ <x ₃ ... (3) is set, and the radial width of the chamfered portion 4 is y ₁ , and the radial width of the tapered portion 5 is y ₂ .
y ₂ <y ₁ ... (4) is set.

  Further, the angle α formed by the chamfered portion 4 with the central axis of the packing 1 is 40 to 50 degrees (about 45 degrees in the figure), and the angle β1 formed by the tapered portion 5 with the central axis of the packing 1 is 15 to 25 degrees (see FIG. Is approximately 20 degrees), and the angle β2 between the axial ends of the groove 7 and the central axis of the packing 1 is set to about 35 to 45 degrees (about 40 degrees in the figure).

  The packing 1 having the above-described configuration is, for example, mounted in an annular packing mounting groove provided on the inner surface of a shaft hole of a housing (not shown), and a pair of seals provided at both axial ends of the inner peripheral surface that is the sliding surface. The lip 3 is slidably brought into close contact with the peripheral surface of a reciprocating shaft (not shown) which is a sliding counterpart. As described above, when the packing 1 is used as a reciprocating packing in a reciprocating portion of a carbon dioxide gas valve, high pressure gas acts on the packing 1 from both sides in the axial direction to generate a differential pressure (for example, axial direction) A high pressure gas of 20 MPa acts from one side and a high pressure gas of 19.8 MPa acts from the other side in the axial direction to generate a differential pressure of 0.2 MPa. Accordingly, the packing 1 functions to seal this differential pressure, and exhibits the following effects by the above configuration.

  That is, in the packing 1 having the above-described configuration, first, since the lip ends 6 each having an acute angle satisfying the expression (1) are formed at both ends in the axial direction of the inner peripheral surface which is a sliding surface. Further, the axial contact width of the seal lip 3 with respect to the mating member can be set short, and the volume of the lip end 6 is made smaller than that of the conventional seal lip. Can be reduced.

  Further, the recess 2 formed between the pair of pointed lip ends 6 in the axial direction acts as a grease reservoir in which grease is sealed. However, when the packing 1 is used for reciprocation, the above (1) According to the relationship of the formula, an action of the grease gradually and gradually flowing out from the concave portion is generated, whereby an oil film can always be formed on the sliding portion.

  Therefore, in combination with these events, the sliding of the packing sliding portion can be reduced, the wear resistance can be improved, and the life of the packing 1 can be extended.

  In addition to this, in the packing 1 having the above-described configuration, the inner stepped portion 8 that satisfies the relationship of the above expression (2) is provided on the inner side of the pair of pointed lip ends 6 in the axial direction. During compression, the packing 1 does not make solid contact with the mating material, so that the reaction force generated can be further reduced, and at this time, a grease pool can still be secured by the groove portion 7 not making solid contact with the mating material. it can. When the packing 1 is compressed in the radial direction, there is a possibility that the taper portion 5 will hit a solid surface, but since the inner surface of the groove portion 7 having a larger inclination angle does not contact the solid surface, the groove portion 7 ensures a grease pool. can do.

  Therefore, in combination with these events, the sliding of the packing sliding portion can be further reduced, the wear resistance can be improved, and the life of the packing 1 can be extended.

  The applicant of the present application conducted a performance comparison test using the product according to the embodiment of the present invention and the product according to the conventional example, and the contents and results will be described below.

<< Comparison Test 1 >>
1. Test conditions (1) Shape of test product As an example of the present invention, a sample having a cross-sectional shape shown in FIG. 1 was used, and a conventional product having a cross-sectional shape shown in FIG. 3 was used. In any case, the compression ratio of the packing is 10%.
(2) Material of Test Product Both the examples of the present invention and the conventional product were EPDM materials (JIS A80 °).
(3) Test apparatus As the test apparatus, a tribology tester (manufactured by CENTER FOR TRIBLOGY) shown in FIG. 2 was used. This test apparatus 21 is a combination of a reciprocating piston 23 connected to a load cell (tribology tester) 22 and a fixed housing 24, and a housing 24 in which the packing 1 is mounted in a packing mounting groove 25 provided on the outer periphery of the piston 23. The sliding resistance was measured in the pulling process (arrow A) and pushing process (arrow B) of the piston 23 by sliding with the inner periphery.
(4) Stroke: 3mm
(5) Speed: 20mm / sec
(6) Surface condition: (A) No grease
(B) With grease (Grease used: Oxigenex FF250)
(7) Number of times: 10 round trips (measurement results show an average of 10 round trips)

（Ｂ）グリース有の場合の摺動抵抗

2. Test result (A) Sliding resistance without grease

(B) Sliding resistance with grease

  As shown in Tables 1 and 2 above, the test results confirmed that the sliding resistance was remarkably reduced according to the present invention both in the absence of grease and in the presence of grease.

<< Comparison Test 2 >>
In addition, under the same conditions as in Comparative Test 1, the “reaction force” and “contact width (width of two lips)” of the example and the conventional product were compared by FEM analysis. However, the following measurement results were obtained.

  Therefore, as shown in Table 3 above, it was confirmed that both the “reaction force” and the “contact width” were significantly reduced according to the present invention.

Sectional drawing of the principal part of the packing which concerns on the Example of this invention Illustration of comparative test equipment Main part sectional drawing of the packing which concerns on a prior art example Cross-sectional view of main parts of a packing according to another conventional example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Packing 2 Recessed part 3 Seal lip 4 Chamfered part 5 Taper part 6 Lip end 7 Groove part 8 Inner level | step difference part 21 Test apparatus 22 Load cell 23 Piston 24 Housing 25 Packing installation groove

Claims (1)

In the ring-shaped packing (1) for reciprocating or rotating mounted on one of the two members facing each other and slidably in close contact with the other member,
The packing (1) is provided with a chamfered portion (4) having a linear cross section at least at both ends in the axial direction on the sliding surface side, and a taper portion (5) having a linear cross section on the axially inner side of the chamfered portion (4). ), The angle formed by the chamfered portion (4) with the central axis is α, and the angle formed by the tapered portion (5) with the central axis is β1.
α> β1
A cusp-like lip end (6) satisfying the above relationship is provided between the chamfered portion (4) and the tapered portion (5) ,
A grease retaining groove (7) having an arcuate cross section is provided between the pair of taper portions (5) in the axial direction, the angle formed by the taper portion (5) and the central axis is β1, and the groove portion (7) is The angle formed with the central axis at the axial end is β2,
β1 <β2
An inner stepped portion (8) that satisfies the above relationship is provided between the tapered portion (5) and the groove portion (7) on the inner side of the pointed lip end (6),
The angle α between the chamfered portion (4) and the central axis is 40 to 50 degrees, the angle β1 between the tapered portion (5) and the central axis is 15 to 25 degrees, and the groove (7) is at the axial end thereof. An angle β2 formed with the central axis is 35 to 45 degrees .

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