JP2015004394A - Sealing structure and manufacturing method of gasket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing structure which improves the sealability in a structure where a gasket is placed in close contact with three members, and to provide a manufacturing method of the gasket.SOLUTION: A sealing structure includes: an inner tube 200; an outer tube 300; a housing 400; a gasket 100 which closely contacts with these members and is made of a rubber elastic body. An axial distance from an end surface of the housing 400 to an annular protruding part 220 provided at the inner tube 200 is set so as to be longer than a radial dimension of an annular gap between the inner tube 200 and the outer tube 300. The gasket 100 includes: a cylindrical gasket body part 110 where one end surface 140 closely contacts with the end surface 410 of the housing 400 and the other end surface 150 closely contacts with a planar side surface 221 in the annular protruding part 220; a first annular protruding part 120 provided at the inner peripheral surface side of the gasket body part 110; and a second annular protruding part 130 provided at the outer peripheral surface side of the gasket body part 110.

Description

  The present invention relates to a sealing structure using a gasket and a method for manufacturing the gasket.

  2. Description of the Related Art Conventionally, there is known a technique for sealing gaps between three members by attaching gaskets to three members, respectively (see Patent Document 1). An example of such a technique will be described with reference to FIG. FIG. 7 is a schematic cross-sectional view showing a sealing structure according to a conventional example.

  In this conventional example, an O-ring 900 that is in close contact with each of three members of an inner tube 600, an outer tube 700, and a casing 800 of a device to which the inner tube 600 and the outer tube 700 are attached is provided. Yes.

  The inner tube 600 is inserted into the tube of the outer tube 700, and the outer tube 700 is fixed to the housing 800 with a fixture such as a bolt. The inner tube 600 is positioned and fixed by a tightening force by the O-ring 900 or the like. In a state where the inner tube 600 and the outer tube 700 are assembled to the housing 800, the outer peripheral surface 610 of the inner tube 600 and the inner peripheral surface of the outer tube 700 are arranged concentrically. Further, the end surface 810 of the housing 800 faces the end surface of the inner tube 600 and the end surface of the outer tube 700.

  On the inner peripheral surface side of the outer tube 700 on the distal end side, a tapered surface 710 that expands in the distal direction is provided. An annular space having a substantially triangular cross section is formed between the tapered surface 710, the outer peripheral surface 610 of the inner tube 600, and the end surface 810 of the housing 800. An O-ring 900 is disposed in the annular space. As a result, the O-ring 900 is in close contact with the tapered surface 710 of the outer tube 700, the outer peripheral surface 610 of the inner tube 600, and the end surface 810 of the housing 800. With such a configuration, the gaps between the members of the inner tube 600, the outer tube 700, and the housing 800 are sealed.

  In the case of the prior art as described above, the outer tube 700 and the casing 800 are fixed to each other because they are fixed by a fixing tool such as a bolt. However, since the inner tube 600 is only positioned by the tightening force of the O-ring 900 or the like, a gap S can be generated between the inner tube 600 and the housing 800. If this gap S becomes too large, the O-ring 900 will not provide sufficient sealing performance. Further, in order to stably exhibit the sealing performance, the O-ring 900 is sufficiently attached to each of the tapered surface 710 of the outer tube 700, the outer peripheral surface 610 of the inner tube 600, and the end surface 810 of the housing 800. It is necessary to adhere. In order to realize this, the dimensional accuracy of each member must be increased. Therefore, the processing accuracy of the tapered surface 710 must be increased. Further, in the case of the O-ring 900, even if the initial dimensional accuracy is increased, there is a problem that the dimensional accuracy deteriorates with time.

  From the above, in the case of the conventional technology as described above, it has been difficult to stably exhibit the sealing performance.

JP-A-6-213088

  The objective of this invention is providing the sealing structure and the manufacturing method of a gasket which aimed at the improvement of the sealing performance in the structure which closely_contact | adheres a gasket with respect to each of three members.

  The present invention employs the following means in order to solve the above problems.

That is, the sealing structure of the present invention is
A first member having an outer peripheral surface;
A second member having an inner peripheral surface disposed concentrically with the outer peripheral surface;
A third member having an end face facing the end face of the first member and the end face of the second member;
A rubber-made elastic gasket that seals the gap between each of the members by closely contacting the first member, the second member, and the third member,
A sealing structure comprising:
A first annular projecting portion projecting radially outward from the outer peripheral surface side of the first member, or a second annular projecting portion projecting radially inward from the inner peripheral surface side of the second member; The axial distance from the end surface to the first annular protrusion or the second annular protrusion is set longer than the radial dimension of the annular gap between the outer peripheral surface of the first member and the inner peripheral surface of the second member. As
The gasket has a cylindrical gasket body portion in which one end surface is in close contact with the end surface of the third member, and the other end surface is in close contact with the planar side surface of the first annular protrusion or the second annular protrusion, A first annular convex portion provided on the inner peripheral surface side of the gasket main body portion and in close contact with the outer peripheral surface of the first member, and provided on the outer peripheral surface side of the gasket main body portion and in close contact with the inner peripheral surface of the second member. A second annular convex portion,
In a state where no external force is applied to the gasket, the distance from one end surface to the other end surface of the gasket main body is the same as that in the state where the first member, the second member, and the third member are assembled. While being set longer than the axial distance from the end face of the three members to the first annular protrusion or the second annular protrusion,
In a state where no external force is applied to the gasket, the inner diameter of the gasket main body is longer than the outer diameter of the outer peripheral surface of the first member, and the inner diameter of the tip of the first annular convex portion is the outer peripheral surface of the first member. The outer diameter of the gasket main body is shorter than the inner diameter of the inner peripheral surface of the second member, and the outer diameter of the tip of the second annular convex portion is smaller than the inner diameter of the inner peripheral surface of the second member. Is also set long.

  According to the present invention, with the above-described configuration, the cylindrical gasket main body has a longer axial dimension than the radial thickness. Therefore, the gasket main body is easily compressed in the axial direction. Therefore, even when a gap is generated between the first member and the third member or between the second member and the third member, the gasket body portion is compressed in the axial direction. The gap between the end surface of the third member and the first annular protrusion or the second annular protrusion can be stably sealed.

  Further, since the gasket is configured such that only the first annular convex portion and the second annular convex portion are compressed so as to be in close contact with the first member and the second member, the gasket is provided in the space where the gasket is mounted. The filling rate can be kept low. Therefore, the load when the gasket is attached can be kept low. Moreover, it is possible to suppress the gasket from being forcibly deformed. Along with this, the sealing performance can be stably exhibited.

In addition, the manufacturing method of the gasket of the present invention,
A molding process for molding a gasket with a mold;
A mold release process for removing the gasket from the mold;
A method for manufacturing a gasket provided in the sealing structure, comprising:
The amount of protrusion to the radially outer side of the second annular protrusion is set larger than the amount of protrusion to the radially inner side of the first annular protrusion,
In the molding process, the mold is installed so that the central axis of the gasket is in the vertical direction,
The mold is
A first mold that forms at least a vertical upper end surface portion of the gasket;
A second mold for forming at least a lower end surface portion of the gasket in the vertical direction and an inner peripheral surface portion including a portion of the first annular convex portion in the gasket;
A third mold for forming an outer peripheral surface portion including at least a portion of the second annular convex portion in the gasket;
With
In the mold release step, the gasket is temporarily held in the third mold by the fitting force to the third mold by the second annular convex portion, and then the gasket is pressed by the pressing member, It is characterized in that a gasket is pushed down from type 3.

  Thus, at the time of mold release, the gasket can be automatically collected by temporarily holding the molded gasket in the third mold and then pushing the gasket down. Accordingly, the gasket can be manufactured by an automatic molding machine.

  As described above, according to the present invention, it is possible to improve the sealing performance in the configuration in which the gasket is in close contact with each of the three members.

FIG. 1 is a schematic cross-sectional view showing a sealing structure according to an embodiment of the present invention. FIG. 2 is a partially broken sectional view of the gasket according to the embodiment of the present invention. FIG. 3 is a schematic cross-sectional view showing a state during molding of the gasket according to the embodiment of the present invention. FIG. 4 is a schematic cross-sectional view showing a state when the gasket according to the embodiment of the present invention is released. FIG. 5 is a schematic cross-sectional view showing a state when the gasket is recovered from the mold according to the embodiment of the present invention. FIG. 6 is a schematic cross-sectional view showing a sealing structure according to a modification of the present invention. FIG. 7 is a schematic cross-sectional view showing a sealing structure according to a conventional example.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be exemplarily described in detail 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 only to those unless otherwise specified. .

(Example)
With reference to FIGS. 1-5, the sealing structure and the manufacturing method of a gasket based on the Example of this invention are demonstrated. In this embodiment, a sealing structure in a pipe joint portion for attaching a double pipe to the apparatus will be described as an example.

<Sealing structure>
In particular, a sealing structure according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic cross-sectional view showing a sealing structure according to an embodiment of the present invention. In FIG. 1, for convenience of explanation, the gasket 100 is shown in a cross-sectional view in a state where no external force is received. In addition, FIG.
In FIG. 2, the inner tube 200 as the first member, the outer tube 300 as the second member, and the housing 400 of the device as the third member are indicated by dotted lines in a cross-sectional view in a state where these are assembled. Yes.

  The sealing structure according to the present embodiment includes the inner tube 200, the outer tube 300, the housing 400, and the gasket 100 made of rubber-like elastic material that is in close contact with the three members.

  The inner tube 200 is inserted into the tube of the outer tube 300, and the outer tube 300 is fixed to the housing 400 with a fixing tool such as a bolt. The inner tube 200 is positioned and fixed by the tightening force of the gasket 100 or the like. In a state where the inner tube 200 and the outer tube 300 are assembled to the housing 400, the outer peripheral surface 210 of the inner tube 200 and the inner peripheral surface 310 of the outer tube 300 are arranged concentrically. Further, the end surface 410 of the housing 400 faces the end surface of the inner tube 200 and the end surface of the outer tube 300. The casing 400 is provided with a hole 420 serving as a fluid passage. The inner pipe 200 and the outer pipe 300 are attached to the casing 400 so that the hole 420 and the inner pipe 200 are connected to each other.

  In addition, the inner tube 200 is provided with an annular protrusion (first annular protrusion) 220 that protrudes radially outward from the outer peripheral surface side. Here, the distance in the axial direction from the end surface 410 of the housing 400 to the annular protrusion 220 is larger than the radial dimension of the annular gap between the outer peripheral surface 210 of the inner tube 200 and the inner peripheral surface 310 of the outer tube 300. It is set long. With this configuration, the planar side surface 221 of the annular protrusion 220, the end surface 410 of the casing 400, the outer peripheral surface 210 of the inner tube 200, and the inner peripheral surface 310 of the outer tube 300 are substantially elongated in cross section. A rectangular annular space is formed. The gasket 100 is mounted in the annular space.

<Gasket>
In particular, the gasket 100 according to the present embodiment will be described in more detail with reference to FIGS.

  The gasket 100 includes a cylindrical gasket main body portion 110, a first annular convex portion 120 provided on the inner peripheral surface side of the gasket main body portion 110, and a second annular convex portion 130 provided on the outer peripheral surface side of the gasket main body portion 110. It consists of. The first annular convex portion 120 and the second annular convex portion 130 are provided near the center in the axial direction. In addition, the gasket 100 which concerns on a present Example is comprised so that it may become a symmetrical shape with respect to the center plane with respect to an axial direction. Thereby, it is not necessary to care about the direction when mounting the gasket 100. Further, the gasket main body 110 has a longer dimension in the axial direction than the thickness in the radial direction. For example, the radial thickness is set to 2 to 3 mm, and the axial dimension is set to about 10 to 11 mm.

  Here, one end surface 140 of the gasket main body 110 is in close contact with the end surface 410 of the housing 400, and the other end surface 150 is in close contact with the planar side surface 221 of the annular projecting portion 220. Further, the first annular convex portion 120 is in close contact with the outer peripheral surface 210 of the inner tube 200, and the second annular convex portion 130 is in close contact with the inner peripheral surface 310 of the outer tube 300.

In the state where no external force is applied to the gasket 100, the distance from one end surface 140 to the other end surface 150 in the gasket main body 110 is such that the inner tube 200 and the outer tube 300 are in relation to the housing 400. In the assembled state, it is set longer than the axial distance from the end surface 410 of the housing 400 to the annular protrusion 220. Further, in the state where no external force is applied to the gasket 100, the inner diameter of the gasket main body 110 is longer than the outer diameter of the outer peripheral surface 210 of the inner tube 200, and the inner diameter of the tip of the first annular convex portion 120 is the inner tube. 200 is shorter than the outer diameter of the outer peripheral surface 210 of the gasket 200, and the outer diameter of the gasket body 110 is the outer tube 3.
00 is shorter than the inner diameter of the inner peripheral surface 310, and the outer diameter of the tip of the second annular convex portion 130 is set longer than the inner diameter of the inner peripheral surface 310 of the outer tube 300.

  In addition, the protrusion amount of the second annular protrusion 130 to the radially outer side is set larger than the protrusion amount of the first annular protrusion 120 to the radially inner side. When the inner diameter of the gasket main body 110 is set to about 11 mm and the outer diameter is set to about 14 mm, the protruding amount of the first annular protrusion 120 is set to about 0.1 mm to 0.5 mm, and the second annular protrusion The protrusion amount of 130 is set to about 0.2 mm to 1.5 mm.

  Moreover, the front-end | tip part of the 1st cyclic | annular convex part 120 is comprised by the curved surface 121 in which a cross section swells inside circularly, and the both sides of this front-end | tip part are comprised by the curved surface 121 which a cross section is dented outside in circular arc shape. . And the curved surface of the front-end | tip part and the curved surface 121 of the both sides are connected smoothly. Note that the curved surfaces 121 on both sides of the tip end portion are set to have a relatively large curvature radius in the cross section. For example, the radius of curvature is set to about 1 mm.

  Similarly, the tip portion of the second annular convex portion 130 is configured by a curved surface that swells outward in a circular arc shape, and both sides of the tip portion are configured by curved surfaces 131 that are recessed inward in a circular arc shape. Has been. And the curved surface of the front-end | tip part and the curved surface 131 of the both sides are connected smoothly. The curved surfaces 131 on both sides of the tip end portion are set to have a relatively large curvature radius in the cross section. For example, this radius of curvature is set to about 2 mm.

<Excellent point of sealing structure according to this embodiment>
As described above, according to the sealing structure according to the present embodiment, the cylindrical gasket body 110 has a longer axial dimension than the radial thickness. Therefore, the gasket main body 110 is easily compressed in the axial direction.

  Here, in the case of the present embodiment, the outer tube 300 and the casing 400 are fixed to each other because they are fixed by a fixing tool such as a bolt. However, since the inner tube 200 is only positioned by the tightening force of the gasket 100 or the like, a gap S may be generated between the inner tube 200 and the housing 400.

  However, in the present embodiment, as described above, the gasket main body 110 is configured to be easily compressed in the axial direction. And the clearance gap between the side surface 221 of the cyclic | annular protrusion part 220 can be sealed stably.

  Further, the first annular convex portion 120 in the gasket 100 is in close contact with the outer peripheral surface 210 of the inner tube 200, and the second annular convex portion 130 is in close contact with the inner peripheral surface 310 of the outer tube 300, whereby the inner tube 200 and the outer tube are in close contact. The annular gap between 300 is sealed. Here, in a state where no external force is applied to the gasket 100, the inner diameter of the gasket main body 110 is longer than the outer diameter of the outer peripheral surface 210 of the inner tube 200, and the inner diameter of the tip of the first annular convex portion 120 is the inner diameter. The outer diameter of the outer peripheral surface 210 of the tube 200 is shorter, the outer diameter of the gasket body 110 is shorter than the inner diameter of the inner peripheral surface 310 of the outer tube 300, and the outer diameter of the tip of the second annular convex portion 130 is the outer tube. It is set longer than the inner diameter of the inner peripheral surface 310 of 300. Thereby, since only the part of the 1st cyclic | annular convex part 120 and the 2nd cyclic | annular convex part 130 is compressed and it is comprised so that it may closely_contact | adhere to the inner tube | pipe 200 and the outer tube | pipe 300, it is a gasket in the space where the gasket 100 is mounted | worn. The filling rate of 100 can be kept low. Therefore, the load when mounting the gasket 100 can be suppressed low. Further, the gasket 100 can be prevented from being forcibly deformed. Along with this, the sealing performance can be stably exhibited.

<Gasket manufacturing method>
In particular, a method for manufacturing the gasket 100 according to the present embodiment will be described with reference to FIGS. The gasket 100 according to the present embodiment is manufactured by molding such as injection molding.

  FIG. 3 is a schematic cross-sectional view showing a state during vulcanization molding in the molding step. In the molding step, the mold is installed so that the central axis of the gasket 100 obtained by molding is in the vertical direction.

  The mold includes a first mold 510, a second mold 520, and a third mold 530. The first mold 510 plays a role of forming at least an upper end surface portion (one end surface 140 portion) in the vertical direction of the gasket 100. The annular groove portion 511 provided in the first mold 510 forms at least the upper end surface portion of the gasket 100 in the vertical direction. The second mold 520 plays a role of forming at least an inner peripheral surface portion including a lower end surface portion in the vertical direction (the other end surface 150 portion) in the gasket 100 and a portion of the first annular convex portion 120 in the gasket 100. ing. The annular groove portion 521 provided in the second mold 520 forms at least the lower end surface portion of the gasket 100 in the vertical direction. Further, the outer peripheral surface 522 of the substantially cylindrical portion provided in the second mold 520 forms an inner peripheral surface portion including at least the portion of the first annular convex portion 120 in the gasket 100. The third mold 530 has a role of forming an outer peripheral surface portion including at least a portion of the second annular convex portion 130 in the gasket 100. In addition, the inner peripheral surface 531 in the third mold 530 forms an outer peripheral surface portion including at least the portion of the second annular convex portion 130 in the gasket 100.

  In the mold release step, as shown in FIG. 4, the first mold 510 is moved upward and the second mold 520 is moved downward. Here, as described above, in the gasket 100, the protrusion amount of the second annular protrusion 130 to the radially outer side is set larger than the protrusion amount of the first annular protrusion 120 to the radially inner side. . Therefore, the molded gasket 100 is left behind by the third mold 530 and held by the third mold 530 by the fitting force to the third mold 530 by the portion of the second annular convex portion 130.

  Here, the part of the 1st annular convex part 120 will be what is called undercut. However, as described above, in the first annular convex portion 120, the tip portion constituted by the curved surface and the curved surfaces 121 on both sides thereof are smoothly connected. Further, the curved surfaces 121 on both sides of the tip portion are set to have a relatively large curvature radius in the cross section. Therefore, the second mold 520 can be moved downward without damaging the first annular convex portion 120.

  After that, as shown in FIG. 5, the gasket 100 can be automatically recovered by moving the pin 600 as the pressing member in the P direction and pressing the gasket 100 to push the gasket 100 down from the third mold 530. it can. Here, as described above, in the second annular convex portion 130, the tip portion formed of a curved surface and the curved surfaces 131 on both sides thereof are smoothly connected. Further, the curved surfaces 131 on both sides of the tip end portion are set to have a relatively large curvature radius. Therefore, the gasket 100 can be pushed down without scratching the second annular convex portion 130.

  By adopting the above manufacturing method, the gasket 100 can be manufactured by an automatic molding machine.

(Modification)
In the embodiment described above, the configuration is shown in which the annular protrusion 220 is provided on the inner tube 200 as the first member, and the other end face 150 of the gasket 100 is in close contact with the annular protrusion 220. However, it is also possible to employ a configuration in which an annular protrusion is provided on the outer tube 300 as the second member, and the other end face 150 of the gasket 100 is in close contact with the annular protrusion. With reference to FIG. 6, the modification of the sealing structure based on the Example of this invention is demonstrated easily. FIG. 6 is a schematic cross-sectional view showing a sealing structure according to a modification of the present invention. In FIG. 6, the same components as those in the above embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In this modification, the inner tube 200 as the first member is not provided with an annular protrusion. Instead, an annular protrusion (second annular protrusion) 320 that protrudes radially inward from the inner peripheral surface side of the outer tube 300 as the second member is provided. Even in such a configuration, the planar side surface 321 of the annular protrusion 320, the end surface 410 of the housing 400, the outer peripheral surface 210 of the inner tube 200, and the inner peripheral surface 310 of the outer tube 300 are elongated. A substantially rectangular annular space is formed. The gasket 100 is mounted in the annular space. Therefore, the same effect as in the case of the above embodiment can be obtained.

(Other)
In the above embodiment, the outer tube 300 and the housing 400 are fixed by a fixing tool such as a bolt and are in close contact with each other, and the gasket 100 is in an environment where a gap S may be generated between the inner tube 200 and the housing 400. The case where is used has been described. However, the gasket 100 is preferably used even in an environment in which the inner tube 200 and the housing 400 are fixed to each other by a fixing tool such as a bolt and are in close contact with each other, and a gap may be generated between the outer tube 300 and the housing 400. be able to.

DESCRIPTION OF SYMBOLS 100 Gasket 110 Gasket main-body part 120 1st cyclic | annular convex part 121 Curved surface 130 2nd cyclic | annular convex part 131 Curved surface 140 End surface 150 End surface 200 Inner pipe 210 Outer peripheral surface 220 Annular protrusion part 221 Side surface 300 Outer pipe 310 Inner peripheral surface 320 Annular protrusion Part 321 Side surface 400 Case 410 End surface 420 Hole 510 First type 511 Groove part 520 Second type 521 Groove part 522 Outer peripheral surface 530 Third type 531 Inner peripheral surface 550 Pin

Claims (2)

A first member having an outer peripheral surface;
A second member having an inner peripheral surface disposed concentrically with the outer peripheral surface;
A third member having an end face facing the end face of the first member and the end face of the second member;
A rubber-made elastic gasket that seals the gap between each of the members by closely contacting the first member, the second member, and the third member,
A sealing structure comprising:
A first annular projecting portion projecting radially outward from the outer peripheral surface side of the first member, or a second annular projecting portion projecting radially inward from the inner peripheral surface side of the second member; The axial distance from the end surface to the first annular protrusion or the second annular protrusion is set longer than the radial dimension of the annular gap between the outer peripheral surface of the first member and the inner peripheral surface of the second member. As
The gasket has a cylindrical gasket body portion in which one end surface is in close contact with the end surface of the third member, and the other end surface is in close contact with the planar side surface of the first annular protrusion or the second annular protrusion, A first annular convex portion provided on the inner peripheral surface side of the gasket main body portion and in close contact with the outer peripheral surface of the first member, and provided on the outer peripheral surface side of the gasket main body portion and in close contact with the inner peripheral surface of the second member. A second annular convex portion,
In a state where no external force is applied to the gasket, the distance from one end surface to the other end surface of the gasket main body is the same as that in the state where the first member, the second member, and the third member are assembled. While being set longer than the axial distance from the end face of the three members to the first annular protrusion or the second annular protrusion,
In a state where no external force is applied to the gasket, the inner diameter of the gasket main body is longer than the outer diameter of the outer peripheral surface of the first member, and the inner diameter of the tip of the first annular convex portion is the outer peripheral surface of the first member. The outer diameter of the gasket main body is shorter than the inner diameter of the inner peripheral surface of the second member, and the outer diameter of the tip of the second annular convex portion is smaller than the inner diameter of the inner peripheral surface of the second member. The sealing structure is characterized by being set longer. A molding process for molding a gasket with a mold;
A mold release process for removing the gasket from the mold;
A method for manufacturing a gasket provided in the sealing structure according to claim 1, comprising:
The amount of protrusion to the radially outer side of the second annular protrusion is set larger than the amount of protrusion to the radially inner side of the first annular protrusion,
In the molding process, the mold is installed so that the central axis of the gasket is in the vertical direction,
The mold is
A first mold that forms at least a vertical upper end surface portion of the gasket;
A second mold for forming at least a lower end surface portion of the gasket in the vertical direction and an inner peripheral surface portion including a portion of the first annular convex portion in the gasket;
A third mold for forming an outer peripheral surface portion including at least a portion of the second annular convex portion in the gasket;
With
In the mold release step, the gasket is temporarily held in the third mold by the fitting force to the third mold by the second annular convex portion, and then the gasket is pressed by the pressing member, A method for manufacturing a gasket, characterized in that the gasket is pushed down from the mold 3.

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