JP2019065868A - Seal structure - Google Patents

Abstract

To provide a seal structure which has high durability even if high pressure is applied to a sealed fluid in a use environment where a rotation speed of a shaft relative to a housing is very high.SOLUTION: A seal structure includes: a shaft which rotates relative to a housing; a resin seal ring which inhibits leakage of a fluid from a fluid space of the housing; an annular seal device which is disposed closer to the atmosphere side than the seal ring and closes a gap between the shaft and the housing; and a drain hole which is formed at the housing and leads to a shaft hole in a position between the seal ring and the seal device. The seal ring is fitted into a peripheral groove formed at the shaft or the housing, closes the gap between the shaft and the housing, and keeps the fluid in the fluid space of the housing. The drain hole discharges the fluid that has flowed from the fluid space and passed through the seal ring.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sealing structure for sealing a gap between a housing and an axis rotatably disposed in the housing.

  Patent Document 1 discloses a sealing device for sealing a gap between a housing and a shaft rotatably disposed relative to the housing. Sealing devices of this type are used to seal fluids in various hydraulic, hydraulic and pneumatic devices. These devices include, for example, engines, motors, generators, pumps, compressors, power steering of automobiles.

Patent No. 4051865 gazette

  Sealing devices of this kind may be used to seal fluids of very high pressure. Also, such sealing devices may be used in equipment where the rotational speed of the shaft relative to the housing is very high.

  Thus, the present invention provides a sealed structure having high durability even when a high pressure is applied to the sealed fluid in a use environment where the rotational speed of the shaft relative to the housing is very high.

  A sealing structure according to an aspect of the present invention includes a housing having a fluid space in which a fluid is disposed, and an axial hole passing through the fluid space, and is disposed in the fluid space of the housing and the axial hole. An axis having a cylindrical portion that rotates relative to the housing, and the shaft or a circumferential groove formed in the housing, closing a gap between the axis and the housing; A seal ring made of resin, which suppresses the leakage of the fluid from the fluid space of the housing, a mounting portion attached to the shaft hole without a gap, and a shaft which is disposed radially inside the mounting portion It has a sliding seal portion that comes into movable contact and an elastic portion made of an elastomer that presses the sliding seal portion radially inward toward the shaft, and is closer to the atmosphere than the seal ring. Distribution And an annular sealing device closing the gap between the shaft and the housing, and formed in the housing and communicating with the axial hole at a position between the seal ring and the sealing device; And a drain hole for draining the fluid that has passed through the seal ring from a fluid space.

  In this aspect, the resin seal ring disposed on the fluid space side of the housing closes the gap between the shaft and the housing to suppress fluid leakage from the fluid space. Due to the presence of a seal ring that receives fluid pressure between the fluid space and the seal, the seal located at the atmosphere side of the seal ring is not exposed to the high pressure of the fluid to be sealed. That is, under pressure relieved by the seal ring, the seal closes the gap between the shaft and the housing. Therefore, even in the use environment where the rotational speed of the shaft relative to the housing is very high, even if high pressure is given to the sealed fluid, the sealing device and hence the sealing structure has high durability and can be used for a long time it can. The drain hole is formed at a position between the seal ring and the sealing device, and drains the sealed fluid that has passed through the seal ring from the fluid space from the axial hole and does not impose an excessive load on the sealing device. This also increases the durability of the sealing device and thus the sealing structure.

  Preferably, the seal ring is formed of an elongated curved rod having two ends, the two ends being slidably brought into contact with each other in the circumferential direction of the seal ring to form the seal The seal rings are continuous in the circumferential direction as long as the contact portions slide against each other as long as the contact portions are in contact with each other as long as the contact portions slide relative to one another.

  In this case, since the seal ring is formed of an elongated curved rod having two ends, the seal ring is mounted on the shaft so as to fit in the circumferential groove formed in the shaft or the housing. Easy to place around. Also, even if the contact portions at the two ends slide against each other, the seal ring maintains a circumferentially continuous endless ring shape as long as the contact portions are in contact with each other, so the seal ring is circumferential Even if extended, the sealing performance of the seal ring is not impaired.

  Preferably, the sliding seal portion of the sealing device is formed with a spiral groove for returning the fluid from the atmosphere side to the fluid space side according to the relative rotation of the shaft and the housing.

  In this case, even if the fluid to be sealed passes through the sealing device, the spiral groove returns the fluid to be sealed from the atmosphere side to the fluid space side, thereby enhancing the sealing performance of the sealing structure.

It is a sectional view showing the sealing structure concerning a 1st embodiment of the present invention. It is a front view which shows the seal ring of the sealing structure of FIG. It is a perspective view which shows the both ends of the stick | rod which comprises the seal ring of FIG. It is a front view showing a seal ring concerning a modification. FIG. 5 is a perspective view showing both ends of a rod that constitutes the seal ring of FIG. 4; It is an expanded view of the sealing lip of the sealing device of the sealing structure of FIG. It is sectional drawing which shows the sealing structure which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the sealing structure which concerns on 3rd Embodiment of this invention. It is sectional drawing which shows the sealing structure which concerns on 4th Embodiment of this invention. It is sectional drawing which shows the sealing structure which concerns on 5th Embodiment of this invention. It is sectional drawing which shows the sealing structure which concerns on 6th Embodiment of this invention. It is sectional drawing which shows the sealing structure which concerns on 7th Embodiment of this invention.

  Hereinafter, a plurality of embodiments according to the present invention will be described with reference to the attached drawings. The sealing structure according to the present invention is used to seal fluid in various hydraulic devices, hydraulic devices and pneumatic devices. These devices include, for example, engines, motors, generators, pumps, compressors, power steering of automobiles.

First Embodiment FIG. 1 is a diagram according to a first embodiment of the present invention, and shows a sealing structure 1 used for an apparatus having two members rotating in relative directions. The sealing structure 1 seals a gap between the shaft 2 and the housing 4 in which the shaft 2 is disposed, and prevents or reduces the leakage of fluid from the fluid space A inside the housing 4 to the atmosphere space B. Let The sealed fluid may be a liquid such as oil or water, or may be a gas.

  The sealing structure 1 comprises a housing 4, a shaft 2, a seal ring 6, a drain hole 8 and a sealing device 10. The housing 4 has a fluid space A in which the fluid to be sealed is disposed, and an axial hole 4A communicating with the fluid space A. The axial hole 4A includes a small diameter portion 4B having a circular cross section on the fluid space A side, and a large diameter portion 4C having a circular cross section coaxial to the small diameter portion 4B and on the atmosphere space B side.

  The shaft 2 is disposed in the fluid space A of the housing 4 and the shaft hole 4A, and rotates relative to the housing 4. That is, the shaft 2 may be a rotating shaft that rotates around the central axis Ax, or the shaft 2 may be fixed and the housing 4 may rotate around the central axis Ax. In this embodiment, the shaft 2 is a cylinder, but at least a portion disposed in the shaft hole 4A may be a cylinder.

  A circumferential groove 2A is formed on the outer peripheral surface of the shaft 2. The circumferential groove 2A is formed at a position overlapping the small diameter portion 4B of the shaft hole 4A. A seal ring 6 made of resin is fitted in the circumferential groove 2A. The seal ring 6 closes the gap between the shaft 2 and the inner peripheral surface of the small diameter portion 4B of the shaft hole 4A to confine the sealed fluid in the fluid space A of the housing 4. The outer portion of the seal ring 6 protrudes radially outward from the circumferential groove 2A, and the outer peripheral surface of the seal ring 6 contacts the inner peripheral surface of the small diameter portion 4B of the shaft hole 4A.

  The sealing device 10 is disposed closer to the atmosphere than the seal ring 6, and closes the gap between the shaft 2 and the inner peripheral surface of the large diameter portion 4C of the shaft hole 4A. The sealing device 10 is an annular shape having the central axis Ax as a symmetry axis, but only the upper part of the sealing device 10 is shown in FIG.

  The sealing device 10 has a double structure, and has an elastic body, ie, an elastic ring 12 formed of an elastomer, and a rigid body, eg, a metal reinforcing ring 14 closely attached to the elastic ring 12 and reinforcing the elastic ring 12. . The reinforcing ring 14 has an L-shaped cross-sectional shape, and the entire reinforcing ring 14 is embedded in the elastic ring 12.

  The sealing device 10 comprises an outer ring 15, an inner ring 16 and a flange 17. The outer annular body 15 is a mounting portion attached to the large diameter portion 4C of the shaft hole 4A without a gap. The manner of attachment may be, for example but not limited to, an interference fit. Outer ring 15 has a portion of elastic ring 12 and a portion of reinforcing ring 14. The portion of the reinforcing ring 14 of the outer annular body 15 exerts a force directed radially outward to the portion of the elastic ring 12 and presses the portion of the elastic ring 12 of the outer annular body 15 firmly against the large diameter portion 4C of the shaft hole 4A. Do.

  The inner annular body 16 is disposed radially inward of the outer annular body 15 coaxially with the outer annular body 15, and the flange 17 connects the outer annular body 15 and the inner annular body 16. The flange 17 has a portion of the elastic ring 12 and a portion of the reinforcing ring 14. The inner annular body 16 is formed only of an elastic body.

  The inner ring 16 has a sealing lip 18. The seal lip 18 is disposed radially inward of the outer annular body 15, and the outer peripheral surface of the shaft 2 slidably contacts the seal lip 18. The seal lip 18 suppresses the leakage of the sealed fluid from the fluid space A side to the atmosphere space B side.

  The seal lip 18 is a protrusion having a triangular cross section having two inclined surfaces (an inclined surface 18A on the fluid space A side and an inclined surface 18B on the atmosphere space B side). FIG. 1 shows a state in which the tip edge between the inclined surface 18A and the inclined surface 18B is deformed in contact with the outer peripheral surface of the shaft 2.

  The elastic ring 12 presses the seal lip 18, which is a sliding seal formed on the elastic ring 12, toward the shaft 2 radially inward. In addition, a garter spring 20 is wound around the inner annular body 16 to compress the inner annular body 16 radially inward. The garter spring 20 applies a force to the seal lip 18 to press the seal lip 18 against the outer peripheral surface of the shaft 2.

  A drain hole 8 is formed in the housing 4. The drain hole 8 passes through the large diameter portion 4C of the shaft hole 4A at a position between the seal ring 6 and the sealing device 10. The drain hole 8 drains the fluid that has passed from the fluid space A through the seal ring 6 and entered the large diameter portion 4C. The fluid is drained through the drain hole 8 by the pressure in the large diameter portion 4C. The number of drain holes 8 may be one or more. The shape and size of the drain hole 8 are not limited.

  As shown in FIGS. 2 and 3, the seal ring 6 is composed of an elongated curved rod having two ends 6A, 6B. The seal ring 6 is formed of a hard resin material having a small coefficient of friction, such as polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE) or the like.

  Since the seal ring 6 is formed of an elongated curved rod having two end portions 6A, the seal ring 6 is fitted in the circumferential groove 2A formed on the outer peripheral surface of the shaft 2 It is easy to arrange around the axis 2.

  The two ends 6A, 6B of the seal ring 6 are slidably brought into contact with each other in the circumferential direction of the seal ring 6 to allow circumferential expansion of the seal ring 6 (and thus radial expansion). It has contact part 6C, 6D, respectively. Each of the contact portions 6C, 6D is an inclined plane (with respect to the axial direction and circumferential direction of the seal ring 6). Even when the contact portions 6C and 6D slide relative to each other, the seal ring 6 maintains an endless ring shape continuous in the circumferential direction as long as the contact portions 6C and 6D contact each other. Therefore, even if the seal ring 6 expands in the circumferential direction (and consequently in the radial direction), the sealing performance of the seal ring 6 is not impaired.

  4 and 5 show an alternative seal ring 7 which can be used in the embodiment. The seal ring 7 is made of the same material as the seal ring 6, and is fitted into the circumferential groove 2A in the same manner as the seal ring 6. The two ends 7A, 7B of the seal ring 7 each have two contacts which allow circumferential expansion of the seal ring 7 (and thus radial expansion).

  Specifically, as shown in FIG. 5, one end 7A has a protruding contact 7E and a sliding guide 7F, and the other end 7B has a protruding contact 7G and a sliding guide 7H. Have. The protruding contact portions 7E and 7G have a shape in which the radially outer portion is extended, and have a space in the radially inner portion. The sliding guides 7F, 7H have a shape in which the radially outer portion is recessed. At the end 7A, the side surface 7E1 of the protruding contact 7E and the side surface 7F1 defining the sliding guide 7F are flush. At the end 7B, the side surface 7G1 of the protruding contact 7G and the side surface 7H1 defining the sliding guide 7H are flush.

  When the two end portions 7A and 7B are butted, the radially inner surface (the lower surface in FIG. 5) of the protruding contact portion 7E of the end portion 7A is the radially outer surface of the sliding guide portion 7H of the end portion 7B ( 5, the radially outer surface (upper surface in FIG. 5) of the sliding guide portion 7F of the end portion 7A is in contact with the radially upper surface of the projecting contact portion 7G of the end portion 7B. It slidably contacts (the lower surface in FIG. 5). Thus, the sliding guide 7H guides the sliding of the projecting contact 7E, and the sliding guide 7F guides the sliding of the projecting contact 7G.

  Further, the side surface 7E1 of the protruding contact portion 7E of the end portion 7A contacts the side surface 7G1 of the protruding contact portion 7G of the end portion 7B and / or the side surface 7H1 on the sliding guide portion 7H. The side surface 7G1 of the protruding contact 7G of the end 7B contacts the side 7E1 of the protruding contact 7E of the end 7A and / or the side 7F1 on the sliding guide 7F.

  Since the seal ring 7 is formed of an elongated curved rod having two end portions 7A, the seal ring 7 is fitted in the circumferential groove 2A formed on the outer peripheral surface of the shaft 2 It is easy to arrange around the axis 2.

  Further, even if the end portions 7A and 7B slide on each other, the side surface 7E1 of the protruding contact portion 7E contacts the side surface 7G1 of the protruding contact portion 7G and / or the side surface 7H1 on the sliding guide portion 7H As long as the side surface 7G1 of the portion 7G is in contact with the side surface 7E1 of the projecting contact portion 7E and / or the side surface 7F1 on the sliding guide portion 7F, the outer portion of the seal ring 7 has a circumferentially continuous endless ring shape Maintain. Therefore, even if the seal ring 7 expands in the circumferential direction (and consequently in the radial direction), the sealing performance of the seal ring 7 is not impaired.

  If the circumferentially continuous endless ring shape of the seal ring is maintained even if the seal ring is expanded in the circumferential direction (and consequently in the radial direction), a seal ring having an end of another structure is used May be

  As understood from FIGS. 2, 3 and 5, the shape of the cross section of the seal rings 6, 7 in the circumferential direction is rectangular. However, the cross section of the seal rings 6 and 7 may be T-shaped, trapezoidal or inverted T-shaped.

  FIG. 6 is an exploded view of the sealing lip 18 of the sealing device 10 of the sealing structure 1. As shown in FIG. 6, a plurality of spiral grooves 19A and 19B are formed on the inclined surface 18B of the seal lip 18 on the air space B side. The grooves 19A and 19B are recessed relative to the inclined surface 18B. That is, the grooves 19A and 19B may be cut into the inclined surface 18B, or a rib may be formed on the inclined surface 18B, and portions relatively recessed with respect to the rib may be used as the grooves 19A and 19B.

  The grooves 19A and 19B play the role of returning the fluid from the atmosphere space B side to the fluid space A side according to the relative rotation of the shaft 2 and the housing 4. That is, with the relative rotation of the shaft 2 and the housing 4, the grooves 19A and 19B perform a pumping action of moving the fluid from the atmosphere space B side to the fluid space A side. The groove 19A is generally adapted to the rotational direction, and returns the fluid from the atmosphere space B side to the fluid space A side when the shaft 2 and the housing 4 rotate relative to each other normally. On the other hand, the groove 19B is normally adapted to the reverse rotation direction opposite to the rotation direction, and returns the fluid from the atmosphere space B side to the fluid space A side when the shaft 2 and the housing 4 are relatively reversely rotated.

  Therefore, even if the fluid to be sealed passes from the fluid space A through the seal ring 6 and further passes through the sealing device 10, the fluid is sealed from the air space B side to the fluid space A side by the spiral grooves 19A and 19B. Is returned, so the sealing performance of the sealing structure 1 is enhanced.

  In this embodiment, grooves 19A, 19B respectively adapted to both rotational directions are formed in the sealing device 10, but only grooves adapted to one rotational direction may be formed in the sealing device 10. The grooves 19A and 19B may be omitted.

  In this embodiment, the resin seal ring 6 disposed on the fluid space A side of the housing 4 closes the gap between the shaft 2 and the housing 4 to prevent leakage of the sealed fluid from the fluid space A. Suppress. Since the seal ring 6 which receives the pressure of the sealed fluid is interposed between the fluid space A and the sealing device 10, the sealing device 10 disposed on the atmosphere side of the seal ring 6 remains at the high pressure of the sealed fluid. Not exposed. That is, under the pressure relieved by the seal ring 6, the sealing device 10 closes the gap between the outer peripheral surface of the shaft 2 and the housing 4. Therefore, in a use environment where the rotational speed of the shaft 2 relative to the housing 4 is very high, the sealing structure 1 has high durability and can be used for a long time even if high pressure is given to the sealed fluid . This effect is achieved in the other embodiments described later.

  Further, in this embodiment, since the seal ring 6 for suppressing the leakage of the sealed fluid is interposed between the fluid space A and the sealing device 10, the sealed fluid in the fluid space A has a high temperature. Even if the sealing device 10 disposed closer to the atmosphere than the seal ring 6 is not exposed to the high temperature of the fluid to be sealed. That is, under the temperature relieved by the seal ring 6, the sealing device 10 closes the gap between the outer peripheral surface of the shaft 2 and the housing 4. Therefore, in a use environment where the rotational speed of the shaft 2 relative to the housing 4 is very high, the sealed structure 1 has high durability and can be used for a long time even if the sealed fluid has a high temperature it can. This effect is achieved also in the second to fourth embodiments described later.

  The sealing structure 1 according to this embodiment includes a sealing device 10 which has a simpler structure and can be manufactured at lower cost than the sealing devices according to second to fourth embodiments described later. However, since the sealing device 10 disposed on the atmosphere side of the seal ring 6 is not directly exposed to the high pressure of the fluid to be sealed, the sealing device 10 can have a simple structure and can be manufactured inexpensively. Compared with the case without 6, it has high durability and can be used for a long time.

  Further, in this embodiment, the drain hole 8 is formed at a position between the seal ring 6 and the sealing device 10, and the fluid to be sealed which has passed through the seal ring 6 from the fluid space A is the large diameter of the shaft hole 4A. It discharges from the part 4C and does not impose an excessive burden on the sealing device 10. This also enhances the durability of the sealing device 10 and hence the sealing structure 1. This effect is achieved in the other embodiments described later.

Second Embodiment FIG. 7 shows a sealing structure 1 according to a second embodiment of the present invention. In the drawings from FIG. 7 onwards, the same reference numerals are used to indicate the already described components, and these components will not be described in detail.

  In this embodiment, the sealing device 10 has a dust lip 22 in addition to the same structure as that of the first embodiment. The dust lip 22 extends obliquely from the inner annular body 16 of the sealing device 10 to the atmosphere space B side and radially inward. The dust lip 22 plays a role of preventing or reducing the entry of foreign matter (eg, mud, dust, liquid different from the sealed fluid) from the air space B side to the fluid space A side.

  The other features are the same as in the first embodiment. Further, the deformation of the seal ring 6 and the deformation of the spiral groove described above in relation to the first embodiment are also applicable to this embodiment.

Third Embodiment FIG. 8 shows a sealing structure 1 according to a third embodiment of the present invention. In this embodiment, the sealing structure 1 comprises a sealing device 30 different from the sealing device 10.

  The sealing device 30 has an elastic ring 12 and two reinforcing rings 32, 34. The reinforcing rings 32, 34 are formed of a rigid body, such as metal. The materials of the reinforcing rings 32, 34 may be the same or different. The reinforcing rings 32 and 34 are in close contact with the elastic ring 12 and reinforce the elastic ring 12.

  The reinforcing ring 32 has an L-shaped cross-sectional shape, and a portion of the reinforcing ring 32 is embedded in the elastic ring 12. The reinforcing ring 34 has a substantially L-shaped cross-sectional shape, and the radially inner end 36 of the reinforcing ring 34 is curved. The entire reinforcing ring 34 is embedded in the elastic ring 12.

  The sealing device 30 comprises an outer ring 15, an inner ring 16 and a flange 17. The outer annular body 15 is a mounting portion attached to the large diameter portion 4C of the shaft hole 4A without a gap. The manner of attachment may be, for example but not limited to, an interference fit. The outer ring 15 has a portion of the elastic ring 12 and a portion of the reinforcing ring 34. The portion of the reinforcing ring 34 of the outer annular body 15 exerts a force directed radially outward to the portion of the elastic ring 12 and presses the portion of the elastic ring 12 of the outer annular body 15 firmly against the large diameter portion 4C of the shaft hole 4A. Do.

  The inner annular body 16 is disposed radially inward of the outer annular body 15 coaxially with the outer annular body 15, and the flange 17 connects the outer annular body 15 and the inner annular body 16. The flange 17 has a portion of the elastic ring 12 and a portion of the reinforcing ring 34.

  The inner ring 16 has a portion of the elastic ring 12, a portion of the reinforcing ring 32 and a portion of the end 36 of the reinforcing ring 34. The portion of the elastic ring 12 of the inner ring 16 has a sealing lip 18 and a dust lip 22.

  The other features are the same as in the first embodiment. Further, the deformation of the seal ring 6 and the deformation of the spiral groove described above in relation to the first embodiment are also applicable to this embodiment.

Fourth Embodiment FIG. 9 shows a sealing structure 1 according to a fourth embodiment of the present invention. In this embodiment, the sealing structure 1 comprises a sealing device 40 different from the sealing device 10, 30.

  The sealing device 40 has an elastic ring 12, a reinforcing ring 14, and a sliding sealing member (sliding sealing portion) 42 made of a heat-resistant resin.

  The sliding sealing member 42 has an L-shaped cross-sectional shape, and a portion of the sliding sealing member 42 is embedded in the elastic ring 12.

  The sealing device 40 comprises an outer ring 15, an inner ring 16 and a flange 17. The outer annular body 15 is a mounting portion attached to the large diameter portion 4C of the shaft hole 4A without a gap. The manner of attachment may be, for example but not limited to, an interference fit. Outer ring 15 has a portion of elastic ring 12 and a portion of reinforcing ring 14. The portion of the reinforcing ring 14 of the outer annular body 15 exerts a force directed radially outward to the portion of the elastic ring 12 and presses the portion of the elastic ring 12 of the outer annular body 15 firmly against the large diameter portion 4C of the shaft hole 4A. Do.

  The inner annular body 16 is disposed radially inward of the outer annular body 15 coaxially with the outer annular body 15, and the flange 17 connects the outer annular body 15 and the inner annular body 16. The flange 17 has a portion of the elastic ring 12 and a portion of the reinforcing ring 14.

  The inner annular body 16 has a portion of the elastic ring 12, a portion of the sliding sealing member 42, and a portion of the radially inner end of the reinforcing ring 14. The portion of the elastic ring 12 of the inner ring 16 has a dust lip 22. A portion of the sliding seal member 42 is embedded in the portion of the elastic ring 12 of the inner annular body 16.

  The sliding sealing member 42 is formed of a hard resin material such as PEEK, PPS, or PTFE that has high heat resistance and a small coefficient of friction. The outer peripheral surface of the shaft 2 slidably contacts the inner peripheral surface of the sliding sealing member 42. The elastic ring 12 presses the sliding sealing member 42, which is a sliding sealing portion fixed to the elastic ring 12, toward the shaft 2 radially inward.

  Preferably, on the inner peripheral surface of the sliding sealing member 42, a spiral groove similar to the grooves 19A and 19B (see FIG. 6) of the first embodiment is formed. Grooves that respectively fit in both rotational directions may be formed in the sliding seal member 42, or only grooves that fit in one rotational direction may be formed in the sliding seal member 42.

  In this embodiment, the sealing device 40 has a sliding sealing member 42 made of a hard resin material having high heat resistance and a small friction coefficient, instead of the sealing lip 18. Therefore, the durability of the sealing device 40 and hence the sealing structure 1 may be further enhanced.

  The other features are the same as in the first embodiment. Further, the modification of the seal ring 6 described above in relation to the first embodiment is also applicable to this embodiment.

  In addition to the sealing devices according to the second to fourth embodiments, various sealing devices can be used in the sealing structure according to the present invention.

Fifth Embodiment FIG. 10 shows a sealing structure 1 according to a fifth embodiment of the present invention. In this embodiment, the sealing structure 1 includes an elastic ring 9 fitted in the circumferential groove 2A of the shaft 2 in addition to the configuration of the first embodiment.

  The elastic ring 9 is an endless ring formed of an elastic body having a higher elasticity than the material of the seal ring 6, for example, an elastomer. As the elastic ring 9, an O-ring, or a ring having a non-compressed cross-sectional shape that is circular can be used. Also, elastic rings of various other cross-sectional shapes may be used. For example, an X ring having an X-shaped cross-sectional shape, a D ring having a D-shaped cross-sectional shape, and a ring having a triangular cross-sectional shape can be used.

  The elastic ring 9 is disposed inside the seal ring 6 and is sandwiched between the bottom surface of the circumferential groove 2A of the shaft 2 and the inner peripheral surface of the seal ring 6. The outer portion of the seal ring 6 protrudes radially outward from the circumferential groove 2A, and the outer peripheral surface of the seal ring 6 contacts the inner peripheral surface of the small diameter portion 4B of the shaft hole 4A. The elastic ring 9 disposed inside the seal ring 6 presses the seal ring 6 radially outward. Also, the leakage of the fluid to be sealed between the inner peripheral surface of the seal ring 6 and the bottom surface of the circumferential groove 2A is prevented or reduced by the elastic ring 9. Therefore, according to this embodiment, the leakage of the fluid to be sealed between the outer peripheral surface of the seal ring 6 and the inner peripheral surface of the small diameter portion 4B of the axial hole 4A is further reduced.

  The elastic ring 9 is constrained by the hard seal ring 6 inside the circumferential groove 2A. Therefore, even if high pressure is applied to the fluid space A, the elastic ring 9 is unlikely to move from the inside of the circumferential groove 2A to the outside.

  The other features are the same as in the first embodiment. Further, the deformation of the seal ring 6 and the deformation of the spiral groove described above in relation to the first embodiment are also applicable to this embodiment. Furthermore, the elastic ring 9 may be used in a sealing structure having the sealing device according to any of the second to fourth embodiments or another sealing device.

Sixth Embodiment FIG. 11 shows a sealing structure 1 according to a sixth embodiment of the present invention. In this embodiment, unlike the configuration of the first embodiment, a circumferential groove 4D is formed on the inner peripheral surface of the small diameter portion 4B of the shaft hole 4A of the housing 4, and a seal ring 56 made of resin is fitted in the circumferential groove 4D. It is done. The circumferential groove 2A is not formed on the shaft 2.

  The seal ring 56 closes the gap between the outer peripheral surface of the shaft 2 and the inner peripheral surface of the small diameter portion 4 B of the shaft hole 4 A, and encloses the sealed fluid in the fluid space A of the housing 4. The inner portion of the seal ring 6 protrudes radially inward from the circumferential groove 4 D, and the inner peripheral surface of the seal ring 6 contacts the outer peripheral surface of the shaft 2.

  The seal ring 56 may be formed of the same material as the seal rings 6, 7 described above for the first embodiment and may be of the same type as the seal ring 6. Although a seal ring 56 similar to the seal ring 7 may be used, in this case, the protruding contact portions 7E and 7G are disposed on the inner side and the sliding guide portion on the outer side, contrary to FIGS. 4 and 5. Preferably, 7F and 7H are arranged. In this case, even if the seal ring 56 expands in the circumferential direction, the inner portion of the seal ring 56 maintains an endless ring shape continuous in the circumferential direction, and the inner peripheral surface of the seal ring 6 extends to the outer peripheral surface of the shaft 2 Maintain contact with

  The other features are the same as in the first embodiment. The deformation of the spiral groove described above in relation to the first embodiment is also applicable to this embodiment. Furthermore, the circumferential groove 4D and the seal ring 56 may be used in a sealing structure having the sealing device according to any of the second to fourth embodiments or another sealing device.

Seventh Embodiment FIG. 12 shows a sealing structure 1 according to a seventh embodiment of the present invention. In this embodiment, the sealing structure 1 includes an elastic ring 59 fitted in the circumferential groove 4D of the shaft hole 4A in addition to the configuration of the sixth embodiment.

  The elastic ring 59 is an endless ring made of an elastic body, such as an elastomer, having higher elasticity than the material of the seal ring 56. As the elastic ring 59, an O-ring, or a ring having a non-compressed cross-sectional shape that is circular can be used. Also, elastic rings of various other cross-sectional shapes may be used. For example, an X ring having an X-shaped cross-sectional shape, a D ring having a D-shaped cross-sectional shape, and a ring having a triangular cross-sectional shape can be used.

  The elastic ring 59 is disposed outside the seal ring 56 and is sandwiched between the bottom surface of the circumferential groove 4D of the shaft hole 4A and the outer peripheral surface of the elastic seal ring 56. The inner portion of the seal ring 56 protrudes radially outward from the circumferential groove 4 D, and the inner peripheral surface of the seal ring 56 contacts the outer peripheral surface of the shaft 2. An elastic ring 59 disposed on the outside of the seal ring 56 presses the seal ring 56 radially inward. Also, the leakage of the fluid to be sealed between the outer peripheral surface of the seal ring 56 and the bottom surface of the circumferential groove 4D is prevented or reduced by the elastic ring 59. Therefore, according to this embodiment, leakage of the fluid to be sealed between the inner peripheral surface of seal ring 56 and the outer peripheral surface of shaft 2 is further reduced.

  The elastic ring 59 is constrained by the hard seal ring 56 inside the circumferential groove 4D. Therefore, even if high pressure is applied to the fluid space A, the elastic ring 59 is unlikely to move from the inside to the outside of the circumferential groove 4D.

  The other features are the same as in the sixth embodiment. Also, the deformation of the seal ring 56 described above with respect to the sixth embodiment and the deformation of the spiral groove with respect to the first embodiment are also applicable to this embodiment. Furthermore, the circumferential groove 4D, the seal ring 56, and the elastic ring 59 may be used in a sealing structure having the sealing device according to any of the second to fourth embodiments or another sealing device.

  Although the embodiments of the present invention have been described above, the above description does not limit the present invention, and various modifications including deletion, addition, and replacement of components can be considered within the technical scope of the present invention. .

A Fluid space B Atmospheric space 1 Sealed structure 2 Shaft 2A circumferential groove 4 housing 4A axial hole 4D circumferential groove 6, 7, 56 seal ring 6A, 6B, 7A, 7B end 6C, 6D contact portion 7E, 7G projecting contact portion 8 Drain hole 10 Sealing device 12 Elastic ring (elastic part)
14 Reinforcement ring 15 Outer ring body (attachment part)
16 inner annular body 17 flange 18 seal lip (sliding seal portion)
19A, 19B spiral groove 30 sealing device 32, 34 reinforcing ring 40 sealing device 42 sliding sealing member (sliding sealing portion)

Claims (3)

A housing having a fluid space in which fluid is disposed, and an axial hole passing through the fluid space;
An axis disposed in the fluid space and the axial hole of the housing and having a cylindrical portion that rotates relative to the housing;
A resin, which is fitted in a circumferential groove formed in the shaft or the housing, and closes a gap between the shaft and the housing to suppress leakage of the fluid from the fluid space of the housing. With seal rings,
A mounting portion attached to the shaft hole without a gap, a sliding sealing portion disposed radially inward of the mounting portion and in which the shaft slidably contacts, and the sliding sealing portion as the shaft An annular sealing device having an elastic portion made of an elastomer, which is pressed radially inward, disposed closer to the atmosphere than the seal ring, and closing a gap between the shaft and the housing; ,
And a drain hole formed in the housing and communicating with the shaft hole at a position between the seal ring and the sealing device, and discharging the fluid having passed through the seal ring from the fluid space. Sealed structure. The seal ring is formed of an elongated curved rod having two ends,
The two ends respectively have contact portions slidably brought into contact with each other in the circumferential direction of the seal ring to allow expansion in the circumferential direction of the seal ring, and the contact portions slide against each other The seal structure according to claim 1, wherein the seal ring is circumferentially continuous as long as the contact portions are in contact with each other. The sliding seal portion of the sealing device is formed with a spiral groove for returning the fluid from the atmosphere side to the fluid space side according to the relative rotation of the shaft and the housing. The sealed structure according to item 1 or 2.

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