JP2007139055A - Sealing device and sealing structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealing device and a sealing structure for developing sealing performance over a long period. <P>SOLUTION: A sealing member 1 has lip portions 11, 12 provided on the inner and outer peripheries on the high pressure side kept in close contact with the groove bottom face of an annular groove 31 of a housing 3 and the peripheral face of a shaft 4, respectively, and a U-shaped groove 10 formed between the lip portions 11, 12. It is provided with a first tapered face 14 on the side of the shaft 4, which is inclined to be gradually farther from the shaft 4 as tending to the low pressure side, and a second tapered face 13 on the groove bottom side of the annular groove 31, which slidably abuts on a tapered face 32 formed on the groove bottom of the annular groove 31 and inclined so that the groove is gradually shallower as tending to the low pressure side. A backup ring 2 is mounted between the sealing member 1 and the side wall on the low pressure side of the annular groove 31. It is provided with an extending portion 20 extending between the first tapered face 14 and the shaft 4 and having a tapered face 21 on which the first tapered face 14 can slidably abut, and a gap between the low pressure side end face of the sealing member 1 and the high pressure side end face of the backup ring 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sealing device and a sealing structure used for, for example, a hydraulic cylinder used as an actuator for a construction machine or a transport vehicle.

  As a sealing device and a sealing structure used for a hydraulic cylinder or the like, a U-shaped packing 100 as shown in FIG. 3 is known. The U-type packing 100 is mounted in an annular groove 201 provided on the inner peripheral surface of the shaft hole of the housing 200, and seals the annular gap between the inner peripheral surface of the shaft hole and the outer peripheral surface of the shaft 300. Side oil leakage is prevented.

  The U-shaped packing 100 includes an outer peripheral lip 102 and an inner peripheral lip 103 on the high pressure side, and a U groove 104 that is recessed in a U shape is formed between the outer peripheral lip 102 and the inner peripheral lip 103 on the high pressure side end surface. An annular rubber seal member.

  The outer peripheral lip 102 protrudes toward the outer peripheral side, the inner peripheral lip 103 protrudes toward the inner peripheral side, the outer peripheral lip 102 protrudes from the groove bottom of the annular groove 201, and the inner peripheral lip 103 extends toward the outer peripheral surface of the shaft 300. , Each has a crushing allowance.

  Therefore, the outer peripheral lip 102 and the inner peripheral lip 103 are subjected to a diameter reducing force and a diameter expanding force, respectively, by the forces received from the groove bottom of the annular groove 201 and the outer peripheral surface of the shaft 300, and the groove bottom of the annular groove 201 and the shaft 300 The annular gap is sealed in close contact with the outer peripheral surface of each.

  Therefore, a compressive stress as shown by an arrow in the figure acts on the groove bottom portion of the U groove 104 surrounded by the dotted line in FIG. Even when a high hydraulic pressure used in a hydraulic cylinder or the like acts on the U-shaped packing 100, a compressive stress always acts on the groove bottom portion of the U groove 104 due to crushing allowance.

Related techniques include those shown in the following documents.
Japanese Utility Model Publication No. 63-22466

  However, when settling occurs due to long-term use or use at a high temperature, or when shrinkage or the like occurs depending on the type of oil used, the crushing margin provided on the lip may be lost.

  When hydraulic pressure is applied to the U-groove 104 in a state where there is no crushing allowance on the lip, the outer peripheral lip 102 is deformed in the outer peripheral direction and the inner peripheral lip 103 is deformed in the inner peripheral direction, thereby expanding the U-groove. As a result, a tensile stress as indicated by an arrow in FIG. 3B acts on the groove bottom portion of the U groove.

  Further, when the lip returns to its original state after being released from the hydraulic pressure, the enlarged U groove is elastically deformed so as to be reduced to the original size, so that the compressive stress is applied to the groove bottom portion of the U groove. Will work.

Therefore, when the hydraulic pressure is repeatedly activated / deactivated with no crushing margin, the deformation of the lip portion is repeated, and tensile / compressive stress acts repeatedly on the groove bottom of the U groove 104.

  If it does so, a crack etc. will generate | occur | produce in the groove bottom part of the U groove 104, oil pressure cannot be hold | maintained, oil leakage will arise, and sealing performance will fall remarkably.

  The present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide a sealing device and a sealing structure capable of exhibiting sealing performance for a long period of time.

  In order to achieve the above object, a sealing device according to the present invention is mounted in an annular groove provided in one member of a housing having a shaft hole and a shaft inserted into the shaft hole. A sealing device that seals the annular gap between the lip portions and a lip portion that is in close contact with the bottom surface of the annular groove and the peripheral surface of the other member of the two members. A sealing device comprising: a seal member having a U-shaped groove formed therein; and a backup ring mounted between the seal member and a low-pressure side wall of the annular groove. Toward the low pressure side of the annular groove, toward the low pressure side formed at the groove bottom of the annular groove on the groove bottom side of the annular groove, and on the groove bottom side of the annular groove. As the groove depth decreases A second taper surface that slidably contacts the tapered surface inclined so that the backup ring extends between the first taper surface and the other member, and the first taper. An extension portion provided with a tapered surface on which the surface can slidably contact, and a gap is provided between the low pressure side end surface of the seal member and the high pressure side end surface of the backup ring. Features.

  According to such a configuration, since the gap is provided between the low pressure side end surface of the seal member and the high pressure side end surface of the backup ring, when the hydraulic pressure acts from the high pressure side, the first taper surface of the backup ring extension portion By sliding the tapered surface and the second tapered surface on the tapered surface of the annular groove bottom, the seal member is pushed into the low pressure side.

  Therefore, when the seal member is crushed or contracted, and the crushing margin is eliminated, the seal member is caused by the taper surface of the backup ring extension portion and the taper surface of the annular groove groove by the hydraulic pressure acting from the high pressure side. It will be pushed into the narrowed space on the low pressure side, and a crushing margin will be formed in the lip portion.

  Then, since the lip portion is pressed from the groove bottom surface of the annular groove and the peripheral surface of the other member, the lip portion generates tensile stress at the groove bottom portion of the U groove even when high hydraulic pressure is applied. The deformation of the lip portion is suppressed.

  As a result, the groove bottom portion of the U groove is in a state where compressive stress is applied, and the occurrence of cracks and the like due to repeated tensile / compressive stress is suppressed in the groove bottom portion of the U groove.

Furthermore, in order to achieve the above object, a sealing structure in the present invention is a sealing structure for sealing an annular gap between a housing having a shaft hole and a shaft inserted into the shaft hole. An annular groove provided on one circumferential surface of the shaft, and a lip portion attached to the annular groove and closely contacting the groove bottom surface and the shaft hole or the other circumferential surface of the shaft A seal member having a U-shaped groove formed between the lip portions, and a backup ring mounted between the seal member and the low-pressure side wall of the annular groove. In the sealing structure, the annular groove has a tapered surface formed at the groove bottom so as to decrease the depth of the groove toward the low pressure side, and the seal member is provided on the low pressure side on the other member side. As you head toward A first tapered surface which is inclined to be separated from the square of the member,
A second taper surface slidably contacting the taper surface of the annular groove on the groove bottom side of the annular groove, and the backup ring is between the first taper surface and the other member. And an extended portion provided with a tapered surface on which the first tapered surface can slidably contact, and between the low pressure side end surface of the seal member and the high pressure side end surface of the backup ring. It is characterized in that a gap is provided in

  As described above, according to the present invention, the sealing performance of the sealing device and the sealing structure can be exhibited over a long period of time.

  The best mode for carrying out the present invention will be exemplarily 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 only to those unless otherwise specified. .

  With reference to FIG. 1 and FIG. 2, the sealing apparatus and sealing structure which concern on an Example are demonstrated. FIG. 1 is a schematic configuration diagram of a sealing structure according to the present embodiment, (a) is a schematic configuration diagram of a sealing device according to the present embodiment, and (b) is attached to the sealing device according to the present embodiment. It is a schematic block diagram of the annular groove made. 2A and 2B are schematic configuration diagrams showing a mounting state of the sealing device according to the present embodiment, where FIG. 2A shows an initial mounting state, and FIG. 2B shows a mounting state when the U-shaped packing is crushed. Indicates.

  As shown in FIG. 1 (a), the sealing device according to the present embodiment is composed of a U-shaped packing 1 and a backup ring 2, and is formed on the inner peripheral surface of the shaft hole of the housing 3 shown in FIG. 1 (b). A sealing structure according to this embodiment is configured together with the annular groove 31.

  The U-shaped packing 1 and the backup ring 2 are mounted in the annular groove 31 to seal the annular gap 5 between the inner peripheral surface of the shaft hole of the housing 3 and the outer peripheral surface of the shaft 4.

  The U-type packing 1 is a rubber annular seal member having a U-groove 10 on the high-pressure side, and as its material, for example, nitrile rubber, hydrogenated nitrile rubber, fluorine rubber or the like is appropriately selected depending on use conditions and the like. .

  The backup ring 2 is an annular member made of a resin material. For example, a tetrafluoroethylene resin (PTFE) or a polyamide resin (PA) having a low friction and good wear resistance is appropriately selected as the material. .

  The U-shaped packing 1 is provided with an outer peripheral lip 11 in close contact with the groove bottom surface of the annular groove 31 of the housing 3 and an inner peripheral lip 12 in close contact with the outer peripheral surface of the shaft 4 on the inner and outer peripheral surfaces on the high pressure side. A U-shaped annular groove 10 is formed between the outer peripheral lip 11 and the inner peripheral lip 12 on the end face on the high pressure side.

  The outer peripheral lip 11 and the inner peripheral lip 12 have crushing allowances with respect to the groove bottom surface of the annular groove 31 and the outer peripheral surface of the shaft 4, respectively, and are pressed from the groove bottom surface of the annular groove 31 and the outer peripheral surface of the shaft 4, respectively. It is in the state that was done.

  Further, the U groove 10 receives a hydraulic pressure from the high pressure side, thereby generating a diameter expanding force on the outer peripheral lip 11 and a diameter reducing force on the inner peripheral lip 12 to enhance the adhesion of the lip.

  However, since the lip is pressed by the crushing margin even when the hydraulic pressure is activated, compressive stress is applied to the groove bottom portion of the U groove.

  Further, the outer peripheral surface from the outer peripheral lip 11 to the low-pressure side end surface is inclined so that the outer diameter becomes smaller toward the low-pressure side (outer peripheral tapered surface 13), and from the inner peripheral lip 12 to the low-pressure side end surface. The inner peripheral surface is inclined so that the inner diameter becomes larger toward the low pressure side (inner peripheral tapered surface 14).

  In other words, the U-shaped packing 1 has a shape in which the inner diameter gradually increases, the outer diameter decreases, and the axial cross section becomes smaller toward the low pressure side.

  The backup ring 2 is provided with an extending portion 20 that protrudes in a cylindrical shape in the high pressure side direction on the inner peripheral side of the high pressure side end surface.

  The extending portion 20 extends between the inner peripheral tapered surface 14 of the U-shaped packing 1 and the outer peripheral surface of the shaft 4 so that the outer diameter of the extending portion 20 decreases as the outer peripheral surface moves toward the high pressure side. (Tapered surface 21) has a tapered shape.

  Further, the inner peripheral surface of the extending portion 20 is in contact with the outer peripheral surface of the shaft 4, and the outer peripheral tapered surface 21 is in contact with the inner peripheral tapered surface 14 of the U-shaped packing 1.

  The inclination angle of the inner peripheral tapered surface 14 of the U-type packing 1 and the inclination angle of the taper surface 21 of the extending portion 20 are set to the same inclination angle, and in the mounted state of the U-type packing 1 and the backup ring 2. The inner circumferential tapered surface 14 and the tapered surface 21 are slidably in contact with each other.

  The shape and dimensions of the U-type packing 1 and the backup ring 2 are such that there is a gap between the low-pressure side end surface of the U-type packing 1 and the high-pressure side end surface of the backup ring 2 when the U-type packing 1 and the backup ring 2 are attached. It is set to be formed.

  As shown in FIG. 1B, the annular groove 31 provided in the inner peripheral surface of the shaft hole of the housing 3 is a taper that is inclined so that the depth of the groove becomes shallower toward a low pressure side at a part of the groove bottom. A surface 32 is formed.

  The tapered surface 32 is set to have the same inclination angle as that of the outer peripheral tapered surface 13 of the U-shaped packing 1, and when the U-shaped packing 1 is mounted, as shown in FIG. They are slidably in contact with each other.

  As shown in FIG. 2, the space in which the U-shaped packing 1 is mounted is gradually increased toward the low pressure side by the tapered surface 21 of the extending portion 20 of the backup ring 2 and the tapered surface 32 of the groove bottom of the annular groove 31. It is formed to be narrow.

  Accordingly, since a gap is provided between the low pressure side end surface of the U-type packing 1 and the high pressure side end surface of the backup ring 2, when hydraulic pressure is applied from the high pressure side, the U-type packing 1 slides on each tapered surface. It will be pushed into a narrow space on the low pressure side.

  If the U-type packing is damaged due to long-term use or high-temperature use, or shrinkage occurs due to the type of oil used, the crushing allowance provided on the lip will be reduced or eliminated. There is a case.

  In such a case, as shown in FIG. 2 (b), the U-shaped packing 1 is moved to the low pressure side by the hydraulic pressure acting from the high pressure side, and is pushed into a narrower space formed on the low pressure side. There is a crushing cost.

  That is, a crushing margin is formed in the lip portion even if settling or shrinkage occurs, and the sealing performance by the lip is maintained for a long time.

  Further, since the outer peripheral lip 11 and the inner peripheral lip 12 are pressed from the groove bottom surface of the annular groove 31 and the outer peripheral surface of the shaft 4, compressive stress acts on the groove bottom portion of the U groove 10.

  Therefore, even if a high hydraulic pressure is applied to the high pressure side, deformation of the lip that causes tensile stress in the groove bottom portion of the U groove 10 is suppressed. The occurrence of repeated tensile / compressive stress is suppressed, and the life of the U-type packing 1 can be extended.

  In this embodiment, only the case where the sealing device is mounted on the housing 3 side has been described, but it is of course possible to mount the sealing device on the shaft 4 side.

  Therefore, for example, in the case of a hydraulic cylinder, an annular groove is provided on the outer peripheral surface of the piston, a sealing device is mounted, and an extending portion 20 is provided on the outer peripheral side of the backup ring 2 so The extension part 20 of the ring 2 can be configured to be in sliding contact with the inner circumferential surface of the cylinder.

  Further, the inclination angle of each tapered surface in the sealing device and the sealing structure according to the present embodiment, the width of the gap between the low-pressure side end surface of the U-shaped packing 1 and the high-pressure side end surface of the backup ring 2, and the like are employed. It is set as appropriate according to the specifications of the device.

It is a schematic block diagram of the sealing device and sealing structure which concern on a present Example. It is a schematic block diagram which shows the mounting state of the sealing device which concerns on a present Example. It is a schematic block diagram of the sealing device and sealing structure which concern on a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 U type packing 10 U groove 11 Outer periphery lip 12 Inner periphery lip 13 Outer periphery taper surface 14 Inner periphery taper surface 2 Backup ring 20 Extension part 21 Tapered surface 3 Housing 31 Annular groove 32 Tapered surface 4 Shaft 5 Annular gap

Claims (2)

A sealing device that is attached to an annular groove provided in one member of a housing having a shaft hole and a shaft inserted into the shaft hole, and seals an annular gap between the two members,
A seal member provided on the inner and outer periphery of the high-pressure side with a lip portion closely contacting the groove bottom surface of the annular groove and the peripheral surface of the other member of the two members, and a U-shaped groove formed between the lip portions; ,
In a sealing device composed of a backup ring mounted between the seal member and a low-pressure side wall of the annular groove,
The sealing member is
A first tapered surface that is inclined toward the other member side so as to be separated from the other member toward the low pressure side;
A second taper surface slidably abutting on the groove bottom side of the annular groove so as to decrease the depth of the groove toward the low pressure side formed on the groove bottom of the annular groove; With
The backup ring includes an extending portion provided between the first tapered surface and the other member and provided with a tapered surface on which the first tapered surface can slidably contact,
A sealing device, wherein a gap is provided between a low pressure side end surface of the seal member and a high pressure side end surface of the backup ring. A sealing structure for sealing an annular gap between a housing having a shaft hole and a shaft inserted into the shaft hole,
An annular groove provided on a peripheral surface of either the shaft hole or the shaft;
A lip portion mounted on the annular groove and in close contact with the bottom surface of the annular groove and the other peripheral surface of the shaft hole or the shaft is provided on the inner and outer periphery of the high-pressure side, and a U-shape is formed between the lip portions. A seal member formed with a groove;
In a sealing structure composed of a backup ring mounted between the seal member and the low-pressure side wall of the annular groove,
The annular groove has a tapered surface inclined at the groove bottom so as to reduce the depth of the groove toward the low pressure side,
The sealing member is
A first tapered surface that is inclined toward the other member side so as to be separated from the other member toward the low pressure side;
A second taper surface slidably contacting the taper surface of the annular groove on the groove bottom side of the annular groove;
The backup ring includes an extending portion provided between the first tapered surface and the other member and provided with a tapered surface on which the first tapered surface can slidably contact,
A sealing structure, wherein a gap is provided between a low pressure side end surface of the seal member and a high pressure side end surface of the backup ring.

Images