JP2008267495A - Sealing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing device comprising a housing and a shaft member to be threaded into an insertion hole of the housing, for preventing the occurrence of biting between cut portions of backup rings adjacent to each other and mounted in an annular groove portion of the shaft member when threading the shaft member into the insertion hole. <P>SOLUTION: The first back-up ring 110 is mounted in the annular groove portion formed in the outer peripheral face of the shaft member 104 so that the cut direction of its cut face from an insertion port side 200 to a corner side 202 is a direction 221 having a component in a thread rotating direction 210 in view from the outer peripheral face side of the shaft member 104. The second back-up ring 112 is mounted in the annular groove portion so that the cut direction of its cut face from the insertion port side 200 to the corner side 202 is a direction 223 having no component in the thread rotating direction 210 in view from the outer peripheral face side thereof. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a seal device used in, for example, a piping portion of an injector of an internal combustion engine, and more particularly to a seal device that combines a seal ring such as an O-ring and a backup ring that prevents protrusion damage of the seal ring.

  As a conventional combination type sealing device of this type, for example, sealing devices disclosed in Patent Literature 1 and Patent Literature 2 are known. Patent Document 1 discloses a sealing device having a housing and a shaft that are concentrically assembled with each other. Patent Document 2 discloses a sealing device including a backup ring in which a part of the circumference is cut obliquely.

  Here, the configuration of a conventional sealing device will be described with reference to FIG.

  FIG. 7 is a cross-sectional configuration diagram illustrating a schematic configuration of the sealing device 100. In FIG. 7, the sealing device 100 includes a housing 102 and a shaft member 104. An insertion hole 102a is formed in the housing 102, and a first screw portion 103 having a thread is formed on a part of the wall surface of the insertion hole 102a. A second screw portion 105 having a thread is also formed on a part of the inner peripheral surface of the shaft member 104 inserted into the insertion hole 102a. The shaft member 104 is fixed to the insertion hole 102a of the housing 102 by screwing the first screw portion 103 and the second screw portion 105 together.

  An annular groove 106 is formed on the outer peripheral surface of the shaft member 104 in the radial direction along the circumferential direction, and a taper is formed on the wall surface of the annular groove 106 on the insertion port side 200 of the insertion hole 102a. A portion 106a is formed. A second backup ring 112, a first backup ring 110, and an O-ring 114 are attached to the annular groove portion 106 from the insertion port side 200. On the inner peripheral surface of the second backup ring 112, a truncated cone-shaped tapered surface 112a is formed along the tapered portion 106a. The tapered surface 112a has a diameter increasing from the back side 202 of the insertion hole 102a toward the insertion port side 200. The taper angles of the tapered surface 112a and the tapered portion 106a are set equal.

  Further, when the first backup ring 110 and the second backup ring 112 are subjected to pressure through the O-ring 114, the diameter of the first backup ring 110 and the second backup ring 112 are cut off in order to closely contact the wall surface of the insertion hole. Yes.

Japanese Patent Laid-Open No. 11-72162 JP 2000-46195 A

  By the way, with the second backup ring 112, the first backup ring 110, and the O-ring 114 attached to the annular groove portion 106 of the shaft member 104, the shaft member 104 is rotated in the screw rotation direction 210, and screwed into the insertion hole 102a. As shown in FIG. 8, when the shaft member 104 is fixed to the housing 102, the cut portion 110 b of the first backup ring may bite into the gap 130 of the cut portion 112 b of the second backup ring 112. .

  The present invention provides a sealing device including a housing and a shaft member screwed into an insertion hole formed in the housing, and adjacent to each other mounted in an annular groove portion of the shaft member when the shaft member is screwed into the insertion hole. The purpose is to prevent the biting that occurs at the cut portion of the backup ring.

  A sealing device according to the present invention includes a shaft member having an annular groove formed in an outer peripheral surface along a circumferential direction, and a housing having an insertion hole into which the shaft member is inserted and screwed to a position including at least the annular groove. A seal ring that is mounted in the annular groove, a first backup ring that is mounted in the annular groove on the insertion port side of the insertion hole from the seal ring, and in which a part of the circumference is cut, and A second backup ring mounted on the annular groove on the insertion port side of the insertion hole from one backup ring, wherein a part of the circumference is inserted into the shaft member when viewed from the outer peripheral surface side of the shaft member And a second backup ring cut obliquely from the insertion hole side toward the back side in a direction not having a component in the screw rotation direction when screwed into the hole.

  In one aspect of the sealing device according to the present invention, the direction of the cut surface of the second backup ring is a direction having a negative component when the screw rotation direction at the time of screwing is positive. And

  In one aspect of the sealing device according to the present invention, the cutting direction of the cut surface of the first backup ring is a direction having a component in the screw rotation direction.

  In one aspect of the sealing device according to the present invention, the inner circumferential surface of the second backup ring on the annular groove side is formed with a tapered surface that expands from the back side toward the insertion side, The annular groove has a tapered portion corresponding to the tapered surface.

  According to the present invention, in a sealing device including a housing and a shaft member that is screwed into an insertion hole formed in the housing, the shaft member is attached to the annular groove portion of the shaft member when screwed into the insertion hole. The biting that occurs at the cut portions of the backup rings adjacent to each other can be prevented.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment specifically showing the best mode for carrying out the invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional configuration diagram of a sealing device 10 according to the present embodiment. The sealing device 10 includes, for example, an inner peripheral surface of an insertion hole formed in a housing and an outer peripheral surface of a shaft member inserted into the insertion hole in a driving force transmission unit of a device on which a high-pressure sealing fluid acts. It is used to prevent the sealing fluid from leaking from the annular gap between the two.

  In FIG. 1, an insertion hole 102 a for inserting a shaft member 104 is formed in the housing 102. A first screw portion 103 having a thread is formed on the wall surface of the insertion hole 102a. Further, a tapered portion 102 b is formed on the wall surface of the insertion hole 102 a so that the opening diameter of the insertion hole 102 a increases from the base end portion 103 a of the first screw portion 103 toward the insertion port side 200.

  An annular groove 106 is formed on the outer peripheral surface of the shaft member 104 inserted into the insertion hole 102 a, and is inserted into the wall surface on the insertion port side 200 of the annular groove 106 from the insertion port side 200 to the back side 202. A tapered portion 106a is formed so that the gap between the hole 102a and the wall surface is wide. Further, the shaft member 104 has a flange 104a on the inner side 202 of the annular groove 106, and a second screw portion 105 that is screwed with the first screw portion 103 is formed on the outer peripheral surface of the flange 104a. .

  Further, an O-ring 114 of a rubber-like elastic body as a seal ring, a first backup ring 110, and a second backup ring 112 are attached to the annular groove portion 106 from the back side 202.

  The first backup ring 110 and the second backup ring 112 are connected to an annular gap between the wall surface of the insertion hole 102a of the housing 102 and the outer peripheral surface of the shaft member 104 when the O-ring 114 receives pressure from the back side 202. Prevent overhang.

  In addition, the first backup ring 110 and the second backup ring 112 are made of a material that does not undergo large elastic deformation when subjected to pressure through the O-ring 114 and has a low sliding resistance, such as a fluorine-based resin such as PTFE. The material is selected.

  Further, the first backup ring 110 and the second backup ring 112 have a substantially rectangular cross section because they can be attached to the annular groove portion 106 and expand when the pressure is applied to closely contact the wall surface of the insertion hole 102a. It is a shape, and a part of the circumference is cut.

  As shown in FIG. 2A, the first backup ring 110 has a cylindrical surface in which the outer peripheral surface 110 e and the inner peripheral surface 110 f are parallel to the axial direction 204, and both side surfaces 110 g and 110 h are orthogonal to each other orthogonal to the axial direction 204. It is composed of surfaces. The rear side surface 110 h contacts the insertion port side side surface of the O-ring 114, and the insertion port side surface 110 g contacts the rear side surface of the second backup ring 112.

  As shown in FIG. 2B, the second backup ring 112 has a cylindrical surface whose outer peripheral surface 112 e is parallel to the axial direction 204, and whose both side surfaces 112 g and 112 h are orthogonal surfaces orthogonal to the axial direction 204. Yes. The inner peripheral surface of the second backup ring 112 is formed by a tapered surface 112a that gradually increases in diameter from the back side toward the insertion port side. The taper surface 112a is set to have a taper angle substantially equal to the taper portion 106a included in the annular groove portion 106.

  In the sealing device 10 configured as described above, in order to screw the shaft member 104 into the insertion hole 102a, at least the annular groove 106 is inserted into the insertion hole 102a in a state in which the rings 110, 112, 114 are attached to the annular groove 106. The shaft member 104 may be inserted into the insertion hole 102a while rotating in the screw rotation direction about the shaft center until it fits inside.

  By the way, conventionally, as shown in FIG. 3, the first backup ring 110 has a screw rotation direction when the cutting direction from the insertion port side 200 to the back side 202 of the cut surface is viewed from the outer peripheral surface side of the shaft member 104. It was attached to the annular groove 106 so that the direction 220 had no component in 210. Further, the second backup ring 112 has an annular groove 106 so that the cutting direction of the cut surface from the insertion port side 200 to the back side 202 is a direction 222 having a component in the screw rotation direction 210 when viewed from the outer peripheral surface side. It was attached to.

  However, when the shaft member 104 is screwed into the insertion hole 102a with the cut surface of each backup ring mounted in the annular groove 106 with the cutting direction as described above, the cut portion of the first backup ring 110 is And the cutting portion of the second backup ring 112 may be bitten.

  That is, when the O-ring 114 comes into contact with the tapered portion 102b of the insertion hole 102a as shown in FIG. 1 when screwing into the insertion hole 102a while rotating the shaft member 104, the screw rotation direction of the O-ring 114 is caused by friction. The rotation of 210 is restricted. Further, the rotation of the first backup ring 110 in contact with the side surface of the insertion port side 200 of the O-ring 114 in the screw rotation direction 210 is also restricted. When the shaft member 104 is inserted into the insertion hole 102a, the O-ring 114 is pushed up to the insertion port side 200 due to the inclination of the tapered portion 102b of the insertion hole 102a. As the O-ring 114 is further pushed up, the first backup ring 110 and the second backup ring 112 are also pushed up to the insertion port side 200. Then, as shown in FIG. 4A, the first backup ring 110 and the second backup ring 112 are expanded in diameter by the inclination of the tapered portion 106a formed in the annular groove portion 106, and the interval between the cut portions of the backup rings is increased. Thereafter, when the shaft member 104 is further rotated and inserted into the insertion hole 102a, as shown in FIG. 4B, the push-up by the O-ring 114 is stopped, and the first backup ring 110 and the second backup ring 112 again. The interval between the cut portions is narrowed.

  Here, when the friction coefficient at the contact surface between the first backup ring 110 and the second backup ring 112 is relatively small, as described above, the second backup ring 112 has a lower rotation than the first backup ring 110 whose rotation is restricted. However, the rotation angle in the screw rotation direction 210 is larger. That is, a relative rotation angle difference is generated between the rotation angle of the first backup ring 110 and the rotation angle of the second backup ring 112. Then, as shown in FIG. 8, the cut portion 110 b of the first backup ring 110 enters the gap 130 of the cut portion 112 b where the second backup ring 112 spreads, and the rotation angle is relatively larger than that of the first backup ring 110. Due to the large rotation of the second backup ring 112, the cutting part 110 b of the first backup ring 110 is pushed up to the insertion port side 200. When the shaft member 104 is further inserted in a state where the end portion is pushed up in this way, the interval between the cut surfaces of the first backup ring 110 and the second backup ring 112 is reduced again, and the first backup ring 110. Biting occurs between the cutting portion 110b of the second backup ring 112 and the cutting portion 112b of the second backup ring 112.

  Therefore, in this embodiment, the cutting direction of the cut surface of the first backup ring 110 and the cut surface of the second backup ring 112 is set to a direction different from the conventional direction shown in FIG.

  More specifically, as shown in FIG. 5, the first backup ring 110 is configured so that the cutting direction from the insertion port side 200 to the back side 202 in the cut surface is a screw rotation as viewed from the outer peripheral surface side of the shaft member 104. It is attached to the annular groove 106 so as to be a direction 221 having a component in the direction 210. That is, when the screw rotation direction 210 is “positive”, the first backup ring 110 has a part of the circumference from the insertion port side 200 toward the back side 202 so as to have a “positive” component. It is cut diagonally. Further, the second backup ring 112 has an annular groove portion so that a cutting direction from the insertion port side 200 to the back side 202 in the cut surface is a direction 223 having no component in the screw rotation direction 210 when viewed from the outer peripheral surface side. 106. In other words, the second backup ring 112 is inserted at a part of the circumference so as to have a “negative” component when the screw rotation direction 210 is “positive” when viewed from the outer peripheral surface side of the shaft member 104. It is cut obliquely from the mouth side 200 toward the back side 202. As shown in FIG. 6, the first backup ring 110 and the second backup ring 112 are attached to the annular groove 106 and the shaft member 104 is screwed into the insertion hole 102a so that the cutting direction is such a direction. Thus, even if the cutting portion 110b of the first backup ring 110 enters the gap 130 of the cutting portion 112b that the second backup ring 112 spreads, the cutting portion 110b of the first backup ring 110 is rotated by the rotation of the second backup ring 112. Is pushed down to the back side 202. Therefore, when the shaft member 104 is screwed into the insertion hole 102a, it is possible to suppress biting that may occur between the cutting portion 110c of the first backup ring 110 and the cutting portion 112c of the second backup ring 112. .

  In the above embodiment, the example in which the inner peripheral surface of the first backup ring 110 is a cylindrical surface parallel to the axial direction 204 has been described. However, like the inner peripheral surface of the second backup ring 112, the inner peripheral surface of the first backup ring may be a tapered surface that gradually increases in diameter from the back side toward the insertion port side. Further, the present invention can be applied to a case where a plurality of annular groove portions are formed on the outer peripheral surface of the shaft member 104, and an O-ring and a plurality of backup rings having a part of the circumference cut adjacent to each annular groove portion. .

It is a section lineblock diagram of a seal device concerning this embodiment. It is a perspective schematic diagram of the 1st backup ring. It is a perspective schematic diagram of the 2nd backup ring. It is a figure for demonstrating the direction of the cut surface formed in each backup ring in the conventional sealing device. It is a figure for demonstrating the motion of each member at the time of screwing a shaft member in an insertion hole. It is a figure for demonstrating the motion of each member at the time of screwing a shaft member in an insertion hole. It is a figure for demonstrating the direction of the cut surface formed in each backup ring in the sealing device of this embodiment. In the sealing device of this embodiment, it is a figure for demonstrating a motion of the cutting part vicinity of each backup ring at the time of screwing a shaft member in an insertion hole. It is a cross-sectional block diagram of the conventional sealing device. In the conventional sealing apparatus, it is a figure for demonstrating the biting which occurs between the cutting parts of each backup ring which generate | occur | produces when screwing a shaft member in an insertion hole.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10,100 Seal apparatus, 102b Tapered part, 102 Housing, 102a Insertion hole, 103 1st thread part, 104 Shaft member, 105 2nd thread part, 106a Tapered part, 106 Annular groove part, 110 1st backup ring, 112a Tapered surface , 112 Second backup ring, 114 O-ring, 200 insertion port side, 202 back side.

Claims (4)

A shaft member formed with an annular groove along the circumferential direction on the outer peripheral surface;
A housing having an insertion hole into which the shaft member is inserted and screwed to a position including at least the annular groove;
A seal ring mounted in the annular groove;
A first backup ring that is attached to the annular groove on the insertion port side of the insertion hole from the seal ring, and a part of the circumference is cut;
A second backup ring mounted in the annular groove on the insertion port side of the insertion hole from the first backup ring, wherein a part of the circumference of the shaft member is seen from the outer peripheral surface side of the shaft member; A second backup ring that is cut obliquely from the insertion port side to the back side in a direction that does not have a component in the screw rotation direction when screwed into the insertion hole;
A sealing device comprising: The sealing device according to claim 1,
The direction of the cut surface of the second backup ring is a direction having a negative component when the screw rotation direction at the time of screwing is positive.
A sealing device characterized by that. The sealing device according to claim 1 or 2,
The cutting direction of the cut surface of the first backup ring is a direction having a component in the screw rotation direction.
A sealing device characterized by that. The sealing device according to any one of claims 1 to 3,
On the inner circumferential surface of the second backup ring on the annular groove side, a tapered surface is formed that expands from the back side toward the insertion side,
The annular groove has a tapered portion corresponding to the tapered surface.
A sealing device characterized by that.

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